JP6904252B2 - Copolymers, photoelectric conversion elements, solar cells and solar cell modules - Google Patents

Description

The present invention relates to copolymers, photoelectric conversion elements, solar cells and solar cell modules.

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 organic solar cells, it is desired to improve the absorption efficiency of sunlight, and it is important to develop a polymer capable of absorbing long-wavelength light. An example has been reported in which a copolymer of a donor monomer and an acceptor monomer (hereinafter referred to as a copolymer) is used as a photoelectric conversion element in order to achieve a longer absorption wavelength.

Specifically, Patent Documents 1 to 3 describe a photoelectric conversion element using a copolymer having a naphthobisthiadiazole unit. Further, Non-Patent Documents 1 and 2 describe examples of photoelectric conversion elements using a copolymer having a naphthobisthiadiazole unit and a benzodithiophene unit.

Chinese Application Publication No. 102060982 International Publication No. 2013/015298 Pamphlet International Publication No. 2012/133793 Pamphlet

J. Am. Chem. Soc. 2011, 133, 9638-9641 Adv. Funct. Mater. 2015, DOI: 10.10012 / adfm. 201501878

High conversion efficiency is required for the practical use of organic thin-film solar cells. However, according to the studies by the present inventors, it may not be possible to obtain sufficient conversion efficiency with the organic thin-film solar cells using the copolymers described in Patent Documents 1 to 3 and Non-Patent Documents 1 and 2. found. The present invention solves the above problems, and an object of the present invention is to provide a photoelectric conversion element having high conversion efficiency.

As a result of diligent studies to solve the above problems, the inventors of the present application have found that the above problems can be solved by using a copolymer having a specific repeating unit, and have achieved the present invention. That is, the first aspect of the present invention has the following gist.
[1] A copolymer having a repeating unit represented by the following formula (I) and a repeating unit represented by the following formula (II) different from the above formula (I).

（式（Ｉ）中、Ｘ¹及びＸ²はそれぞれ独立して周期表第１６族元素から選ばれる原子を表し、Ｒ¹及びＲ²の一方が１価の有機基で他方が水素原子またはハロゲン原子であり、Ｒ³及びＲ⁴の一方が１価の有機基で他方が水素原子またはハロゲン原子を表し、Ｄ１はドナー性構成単位を表す。式（ＩＩ）中、Ａｒ³およびＡｒ⁴はそれぞれ独立して、置換基を有していてもよい芳香族基を表し、ｃ及びｄはそれぞれ独立して０以上２以下の整数を表し、Ａはアクセプター性構成単位又は直接結合を表し、Ｄ２はドナー性構成単位を表す。なお、式（ＩＩ）において、Ａが直接結合である場合、式（ＩＩ）中のｃ及びｄはそれぞれ独立して１又は２である。）
［２］前記式（Ｉ）において、Ｒ^１およびＲ⁴は独立して１価の有機基であり、Ｒ^２およびＲ^３は独立して水素原子またはハロゲン原子である、［１］に記載のコポリマー。
［３］前記式（Ｉ）中、Ｄ１が下記式（ＩＶ）又は下記式（Ｖ）で表わされる構成単位であることを特徴とする［１］又は［２］に記載のコポリマー。

(In formula (I), X ¹ and X ² each independently represent an atom selected from Group 16 elements of the periodic table, ^one of R ^{1 and R 2} is a monovalent organic group and the other is a hydrogen atom or halogen. It is an atom, one of R ³ and R ⁴ represents a monovalent organic group and the other represents a hydrogen atom or a halogen atom, and D1 represents a donor constituent unit. In formula (II), Ar ³ and Ar ⁴ are respectively. Independently, an aromatic group which may have a substituent is represented, c and d each independently represent an integer of 0 or more and 2 or less, A represents an accepting structural unit or a direct bond, and D2 represents a direct bond. Represents a donor constituent unit. In formula (II), when A is a direct bond, c and d in formula (II) are independently 1 or 2, respectively.)
[2] In the above formula (I), R ¹ and R ⁴ are independently monovalent organic groups, and R ² and R ³ are independently hydrogen atoms or halogen atoms, according to [1]. Copolymer.
[3] The copolymer according to [1] or [2], wherein D1 is a structural unit represented by the following formula (IV) or the following formula (V) in the above formula (I).

（式（ＩＶ）中、Ａｒ⁵及びＡｒ⁶は、それぞれ独立して、置換基を有していてもよい芳香環を表し、Ｘ³及びＸ⁴は、それぞれ独立して、Ｑ¹（Ｒ⁵）（Ｒ⁶）、Ｑ²（Ｒ⁷）、硫黄原子（Ｓ）、酸素原子（Ｏ）又は直接結合を表す。ただし、Ｘ³及びＸ⁴の一方が直接結合である場合、Ｘ³及びＸ⁴のうちの他方の基は、Ｑ¹（Ｒ⁵）（Ｒ⁶）、Ｑ²（Ｒ⁷）、硫黄原子（Ｓ）又は酸素原子（Ｏ）である。なお、Ｑ¹は、周期表第１４族元素から選ばれる原子を表し、Ｑ²は、周期表第１５族元素から選ばれる原子を表し、Ｒ⁵及びＲ⁶はそれぞれ独立して、水素原子、ハロゲン原子又は１価の有機基を表し、Ｒ⁷は水素原子、ハロゲン原子又は１価の有機基を表す。式（Ｖ）中、Ａｒ⁷及びＡｒ⁸は、それぞれ独立して、置換基を有していてもよい芳香環を表し、Ｘ⁵及びＸ⁶はそれぞれ独立して、Ｑ³（Ｒ⁸）で表わされる基を表す。なお、Ｑ³は、周期表第１４族元素から選ばれる原子を表し、Ｒ⁸は水素原子、ハロゲン原子又は１価の有機基を表す。
［４］前記式（ＩＩ）で表わされる繰り返し単位が下記式（ＶＩＩ）で表わされる繰り返し単位であることを特徴とする［１］〜［３］のいずれかに記載のコポリマー。

(In formula (IV), Ar ⁵ and Ar ⁶ each independently represent an aromatic ring which may have a substituent, and X ³ and X ⁴ each independently ^{represent Q 1} (R ^5). ) (R ⁶ ), Q ² (R ⁷ ), sulfur atom (S), oxygen atom (O) or direct bond. However, if one of X ³ and X ⁴ is a direct bond, X ³ and X the other group of ^{4, Q 1 (R 5) (} R 6), Q 2 (R 7), a sulfur atom (S) or oxygen atom (O). in addition, Q ¹ is the periodic table ^{Q 2} represents an atom selected from Group 14 elements, Q 2 represents an atom selected from Group 15 elements in the periodic table, and R ⁵ and R ⁶ independently represent a hydrogen atom, a halogen atom, or a monovalent organic group. ^{R 7} represents a hydrogen atom, a halogen atom or a monovalent organic group. In the formula (V), Ar ⁷ and Ar ⁸ each independently represent an aromatic ring which may have a substituent. , X ⁵ and X ⁶ each independently represent a group represented by ^{Q 3} (R ^{8 ). Q 3} represents an atom selected from Group 14 elements of the periodic table, and R ⁸ is a hydrogen atom. Represents a halogen atom or a monovalent organic group.
[4] The copolymer according to any one of [1] to [3], wherein the repeating unit represented by the formula (II) is a repeating unit represented by the following formula (VII).

（式（ＶＩＩ）中、Ｘ⁷及びＸ⁸はそれぞれ独立して、周期表第１６族元素から選ばれる原子を表し、Ｒ¹¹〜Ｒ¹⁴はそれぞれ独立して水素原子、ハロゲン原子又は１価の有機基を表し、Ａはアクセプター性構成単位又は直接結合を表し、Ｄ２はドナー性構成単位を表す。）
［５］前記式（ＩＩ）中のＡが式（ＶＩＩＩ）又は式（ＩＸ）で表わされる構成単位である、［１］〜［４］のいずれかに記載のコポリマー。

(In formula (VII), X ⁷ and X ⁸ each independently represent an atom selected from the Group 16 elements of the periodic table, and R ^{11 to} R ¹⁴ independently represent a hydrogen atom, a halogen atom or a monovalent atom. Represents an organic group, A represents an acceptor component or a direct bond, and D2 represents a donor component.)
[5] The copolymer according to any one of [1] to [4], wherein A in the formula (II) is a structural unit represented by the formula (VIII) or the formula (IX).

（式（ＶＩＩＩ）中、Ａｒ⁹は、置換基を有していてもよい芳香族炭化水素環、置換基を有していてもよい芳香族複素環、又は置換基を有していてもよい脂肪族複素環を表し、Ｘ⁹及びＸ¹⁰はそれぞれ独立して、窒素原子（Ｎ）又はＱ⁴（Ｒ¹⁵）を表す。なお、Ｑ⁴は周期表第１４族元素から選ばれる原子を表し、Ｒ¹⁵は、水素原子、ハロゲン原子又は１価の有機基を表す。式（ＩＸ）中、Ａｒ¹⁰は、置換基を有していてもよい芳香族炭化水素環、置換基を有していてもよい芳香族複素環、又は置換基を有していてもよい脂肪族複素環を表し、Ｘ¹¹は、周期表第１６族元素から選ばれる原子を表す。
［６］前記式（ＩＩ）中、Ｄ２が下記式（ＩＶ）又は下記式（Ｖ）で表わされる繰り返し単位である、［１］〜［５］のいずれかに記載のコポリマー。

(In formula (VIII), Ar ⁹ may have an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocycle which may have a substituent, or a substituent. It represents an aliphatic heterocycle, and X ⁹ and X ¹⁰ independently represent a nitrogen atom (N) or Q ⁴ (R ¹⁵ ). Q ⁴ represents an atom selected from Group 14 elements of the periodic table. , R ¹⁵ represents a hydrogen atom, a halogen atom or a monovalent organic group. In the formula (IX), Ar ¹⁰ has an aromatic hydrocarbon ring and a substituent which may have a substituent. It represents an aromatic heterocycle which may have a substituent, or an aliphatic heterocycle which may have a substituent, and X ¹¹ represents an atom selected from the Group 16 elements of the periodic table.
[6] The copolymer according to any one of [1] to [5], wherein D2 is a repeating unit represented by the following formula (IV) or the following formula (V) in the above formula (II).

（式（ＩＶ）中、Ａｒ⁵及びＡｒ⁶は、それぞれ独立して、置換基を有していてもよい芳香環を表し、Ｘ³及びＸ⁴は、それぞれ独立して、Ｑ¹（Ｒ⁵）（Ｒ⁶）、Ｑ²（Ｒ⁷）、硫黄原子（Ｓ）、酸素原子（Ｏ）又は直接結合を表す。ただし、Ｘ³及びＸ⁴の一方が直接結合である場合、Ｘ³及びＸ⁴のうちの他方の基は、Ｑ¹（Ｒ⁵）（Ｒ⁶）、Ｑ²（Ｒ⁷）、硫黄原子（Ｓ）又は酸素原子（Ｏ）である。なお、Ｑ¹は、周期表第１４族元素から選ばれる原子を表し、Ｑ²は、周期表第１５族元素から選ばれる原子を表し、Ｒ⁵及びＲ⁶はそれぞれ独立して、水素原子、ハロゲン原子又は１価の有機基を表し、Ｒ⁷は水素原子、ハロゲン原子又は１価の有機基を表す。式（Ｖ）中、Ａｒ⁷及びＡｒ⁸は、それぞれ独立して、置換基を有していてもよい芳香環を表し、Ｘ⁵及びＸ⁶はそれぞれ独立して、Ｑ³（Ｒ⁸）で表わされる基を表す。なお、Ｑ³は、周期表第１４族元素から選ばれる原子を表し、Ｒ⁸は水素原子、ハロゲン原子又は１価の有機基を表す。）
［７］前記式（Ｉ）中、Ｄ１が下記式（ＶＩ）で表わされる繰り返し単位であり、前記式（ＩＩ）中、Ａが式（Ｘ）で表わされる繰り返し単位であり、Ｄ２が式（ＶＩ）で表わされる繰り返し単位である、［１］〜［６］のいずれかに記載のコポリマー。

(In formula (IV), Ar ⁵ and Ar ⁶ each independently represent an aromatic ring which may have a substituent, and X ³ and X ⁴ each independently ^{represent Q 1} (R ^5). ) (R ⁶ ), Q ² (R ⁷ ), sulfur atom (S), oxygen atom (O) or direct bond. However, if one of X ³ and X ⁴ is a direct bond, X ³ and X the other group of ^{4, Q 1 (R 5) (} R 6), Q 2 (R 7), a sulfur atom (S) or oxygen atom (O). in addition, Q ¹ is the periodic table ^{Q 2} represents an atom selected from Group 14 elements, Q 2 represents an atom selected from Group 15 elements in the periodic table, and R ⁵ and R ⁶ independently represent a hydrogen atom, a halogen atom, or a monovalent organic group. ^{R 7} represents a hydrogen atom, a halogen atom or a monovalent organic group. In the formula (V), Ar ⁷ and Ar ⁸ each independently represent an aromatic ring which may have a substituent. , X ⁵ and X ⁶ each independently represent a group represented by ^{Q 3} (R ^{8 ). Q 3} represents an atom selected from Group 14 elements of the periodic table, and R ⁸ is a hydrogen atom. Represents a halogen atom or a monovalent organic group.)
[7] In the formula (I), D1 is a repeating unit represented by the following formula (VI), in the formula (II), A is a repeating unit represented by the formula (X), and D2 is a repeating unit represented by the formula (X). The copolymer according to any one of [1] to [6], which is a repeating unit represented by VI).

（式（Ｘ）中、Ｒ¹⁶及びＲ¹⁷は、水素原子、ハロゲン原子又は１価の有機基を表す。式（ＶＩ）中、Ｒ⁹及びＲ¹⁰はそれぞれ独立して、水素原子、ハロゲン原子又は１価の有機基を表す。）
［８］前記式（Ｉ）中、Ｒ¹、Ｒ⁴がそれぞれ独立して、炭素数１以上２０以下の脂肪族炭化水素基である、［１］〜［７］のいずれかに記載のコポリマー。
［９］コポリマー中、前記式（ＩＩ）で表わされる繰り返し単位数に対する前記式（Ｉ）で表わされる繰り返し単位数の比率が０．１以上９以下である、［１］〜［８］のいずれかに記載のコポリマー。
［１０］重量平均分子量が１０，０００以上３００，０００以下である、［１］〜［９］のいずれかに記載のコポリマー。
［１１］基材上に、一対の電極と、該一対の電極間に活性層と、を有する光電変換素子であって、前記活性層が［１］〜［１０］のいずれかに記載のコポリマーを含有することを特徴とする光電変換素子。［１２］［１１］に記載の光電変換素子を有する太陽電池モジュール。

(In formula (X), R ¹⁶ and R ¹⁷ represent hydrogen atoms, halogen atoms or monovalent organic groups. In formula (VI), R ⁹ and R ¹⁰ are independent hydrogen atoms and halogen atoms, respectively. Or it represents a monovalent organic group.)
[8] The copolymer according to any one of [1] to [7], ^{wherein R 1} and R ⁴ are independently aliphatic hydrocarbon groups having 1 to 20 carbon atoms in the above formula (I). ..
[9] Any of [1] to [8], wherein the ratio of the number of repeating units represented by the formula (I) to the number of repeating units represented by the formula (II) in the copolymer is 0.1 or more and 9 or less. Copolymer described in Crab.
[10] The copolymer according to any one of [1] to [9], which has a weight average molecular weight of 10,000 or more and 300,000 or less.
[11] A photoelectric conversion element having a pair of electrodes and an active layer between the pair of electrodes on a substrate, wherein the active layer is the copolymer according to any one of [1] to [10]. A photoelectric conversion element characterized by containing. [12] A solar cell module having the photoelectric conversion element according to [11].

The present invention also provides the following second aspect.
[13] A copolymer having a repeating unit represented by the following formula (I).

(In formula (I), X ¹ and X ² each independently represent an atom selected from Group 16 elements of the periodic table, and R ¹ and R ⁴ are independent and linear with 9 or more carbon atoms. It represents an aliphatic hydrocarbon group or a branched aliphatic hydrocarbon group having 9 or more carbon atoms in the main chain and 5 or less carbon atoms in the side chain, and R ² and R ³ are independent of each other. , Hydrogen atom or halogen atom. D1 represents a structural unit represented by the formula (IV) or the formula (V).

(In formula (IV), Ar ⁵ and Ar ⁶ each independently represent an aromatic ring which may have a substituent. X ³ and X ⁴ each independently ^{represent Q 1} (R ^5). ) (R ⁶ ), Q ² (R ⁷ ), sulfur atom (S), oxygen atom (O) or direct bond. However, if one of X ³ and X ⁴ is a direct bond, X ³ and X The other group of ^{4 is Q 1} (R ⁵ ) (R ⁶ ), Q ² (R ⁷ ), sulfur atom (S) or oxygen atom (O). Q ¹ is Group 14 of the periodic table. Represents an atom selected from an element, R ⁵ and R ⁶ independently represent a hydrogen atom, a halogen atom or a monovalent organic group. Q ² represents an atom selected from the Group 15 element of the periodic table, and R ⁷ represents a hydrogen atom, a halogen atom or a monovalent organic group.)

(In the formula (V), Ar ⁷ and Ar ⁸ each independently represent an aromatic ring which may have a substituent. X ⁵ and X ⁶ are represented by ^{Q 3} (R ⁸ ), respectively. Q ³ represents an atom selected from the Group 14 elements of the periodic table, and R ⁸ represents a hydrogen atom, a halogen atom, or a monovalent organic group.)
[14] The copolymer according to [13], wherein D1 is a structural unit represented by the following formula (III) in the above formula (I).

(In formula (III), X ¹² and X ¹³ each independently represent an atom selected from the Group 16 elements of the periodic table. R ⁹ and R ¹⁰ independently represent a hydrogen atom, a halogen atom or a monovalent atom, respectively. Represents an organic group of.)
[15] The copolymer according to [14], wherein the structural unit represented by the formula (III) is a structural unit represented by the formula (XV).

(In the formula (XV), X ¹² ~X ¹⁵ are each independently, .R ²⁰ to R ²⁵ representing an atom selected from the Periodic Table Group 16 element, each independently, a hydrogen atom, a halogen atom Alternatively, it represents a monovalent organic group, ^{one of R 20 to} R ²² is a monovalent organic group, and the remaining two groups are independently hydrogen or halogen atoms, R ^{23 to} R ^25. One of the groups is a monovalent organic group, and the remaining two groups are independently hydrogen or halogen atoms.)
[16] A photoelectric conversion element having a pair of electrodes and an active layer between the pair of electrodes on a substrate, wherein the active layer is the copolymer according to any one of [13] to [15]. A photoelectric conversion element containing.
[17] A solar cell module having the photoelectric conversion element according to [16].

According to the first aspect of the present invention, it is possible to provide a photoelectric conversion element having high conversion efficiency. Furthermore, according to the first aspect of the present invention, it is possible to provide a photoelectric conversion element having high light resistance. Further, according to the second aspect of the present invention, it is possible to provide a photoelectric conversion element having high conversion efficiency.

It is sectional drawing which shows typically the structure of the photoelectric conversion element as one Embodiment of this invention. It is sectional drawing which shows typically the structure of the solar cell as one Embodiment of this invention. It is sectional drawing which shows typically the structure of the solar cell module as one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail. The description of the constituent elements described below is an example (representative example) of the embodiment of the present invention, and the present invention is not specified in these contents unless the gist thereof is exceeded. That is, each embodiment described in the present specification can be variously modified within a range that does not deviate from the gist thereof, and within a feasible range, the features described by the other embodiments. Can be combined.

<1. Copolymer according to the first aspect of the present invention>
The copolymer according to the embodiment of the present invention (copolymer according to the first aspect) has a repeating unit represented by the following formula (I) and a repeating unit represented by the following formula (II) different from the following formula (I). It has a unit and. In the present invention, the repeating unit represented by the formula (II) different from the formula (I) is a repeating unit in which the repeating unit represented by the formula (II) is the same as the repeating unit represented by the formula (I). It means that it is not. That is, even when the repeating unit represented by the formula (I) and the repeating unit represented by the formula (II) differ only in the substituent in the present invention, the repeating unit represented by the formula (I) and the repeating unit represented by the formula (II) are used. It is a repeating unit different from the represented repeating unit.

It should be noted that the copolymer according to the embodiment of the present invention has the repeating unit represented by the formula (I) and the repeating unit represented by the formula (II) to improve the conversion efficiency of the photoelectric conversion element. The reason can be considered. That is, when the copolymer has only the repeating unit represented by the formula (I), it tends to be difficult to obtain high conversion efficiency because the solubility is low and only light in a specific absorption wavelength region range can be absorbed. is there. On the other hand, when the copolymer has a repeating unit represented by the formula (II) in addition to the repeating unit represented by the formula (I), the solubility can be improved and light in a wider wavelength region can be absorbed. High conversion efficiency can be obtained because it is possible.

In addition, since organic thin-film solar cells are expected to be used in an environment exposed to sunlight, it is desirable not only to improve conversion efficiency but also to improve light resistance in order to put organic thin-film solar cells into practical use. Is done. However, according to the study by the present inventors, even a photoelectric conversion device using a copolymer having a repeating unit represented by the formula (I), the combination of and R ¹ to R ^4, by further repeating units contained It has been found that when irradiated with light, the element may deteriorate and the conversion efficiency may decrease. It is considered that this is mainly because the copolymer constituting the photoelectric conversion element is deteriorated by light. In the copolymer of the first aspect of the present invention, the copolymer has a repeating unit represented by the formula (II) in addition to the repeating unit represented by the formula (I), and ^one of R ^{1 and R 2} is monovalent. Since the other is a hydrogen atom or a halogen atom and one of R ³ and R ⁴ is a monovalent organic group and the other is a hydrogen atom or a halogen atom, the conversion efficiency is high even after irradiation with light. It is possible to provide a photoelectric conversion element having high light resistance and which is less likely to decrease. This mechanism is not clear, but the following reasons can be considered. By adding the repeating unit represented by the formula (II) in addition to the repeating unit represented by the formula (I), the crystallinity of the copolymer and / or the rigidity of the copolymer is relaxed, and a dense film is likely to be formed, resulting in a dense film. It is considered that the resistance to photooxidation in the atmosphere is improved because oxygen and water are less likely to enter the membrane. Further, it is considered that the progress of aggregation of the copolymer in the membrane can be suppressed under light irradiation. Further, ^one of R 1 and R ² is a monovalent organic group and the other is a hydrogen atom or a halogen atom, and one of R ³ and R ⁴ is a monovalent organic group and the other is a hydrogen atom or a halogen atom. As a result, steric hindrance in the copolymer is suppressed, which makes it easier to obtain flatness. For the above reasons, it is considered that a copolymer having high light resistance can be obtained and a photoelectric conversion element having high light resistance can be provided. Furthermore, since the copolymer has high light resistance, it can be manufactured with high productivity even in a light irradiation environment when manufacturing a photoelectric conversion element.

In formula (I), X ¹ and X ² each independently represent an atom selected from the elements of Group 16 of the periodic table, and specifically, an oxygen atom (O), a sulfur atom (S), and a selenium atom (Se). ) Or tellurium atom (Te). Among them, X ¹ and X ² are preferably sulfur atoms (S) because they exhibit good semiconductor characteristics.

In formula (I), ^one of R 1 and R ² is a monovalent organic group and the other is a hydrogen atom or a halogen atom, and one of R ³ and R ⁴ is a monovalent organic group and the other is a hydrogen atom or a halogen. Represents an atom. In the present invention, the monovalent organic group means a monovalent group having one or more carbon atoms. The number of carbon atoms of the monovalent organic group is not particularly limited, but is usually 1 or more, preferably 4 or more in order to improve solubility, more preferably 6 or more, and 10 or more. On the other hand, in order to prevent the steric hindrance with the adjacent constituent units from becoming large, it is preferably 30 or less, more preferably 20 or less, and particularly preferably 18 or less.

Specific examples of the monovalent organic group are not particularly limited, but in order to improve the solubility and the π stackability between the copolymers, a chain aliphatic hydrocarbon group, an alkoxy group, an alkylcarbonyl group, and an alkoxy group are used. Examples thereof include a carbonyl group and an alkylthio group.

Examples of the chain-shaped aliphatic hydrocarbon group include a linear aliphatic hydrocarbon group and a branched aliphatic hydrocarbon group. The number of carbon atoms constituting the aliphatic hydrocarbon group is not particularly limited, but is usually 1 or more, preferably 4 or more in order to improve solubility, and preferably 6 or more. Further preferably, it is particularly preferably 10 or more, while it is preferably 30 or less, more preferably 20 or less, and 18 or less in order to prevent steric hindrance with adjacent constituent units from becoming large. It is particularly preferable to have.

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, but for example, an n-butyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-decyl group, an n-dodecyl group, a tridecyl group, a tetradecyl group. , Pentadecyl group, hexadecyl group, heptadecyl group or octadecyl 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 one that can form a bond with another free valence as described in the Organic Chemistry / Biochemical Nomenclature (above) (Revised 2nd Edition, Nankodo, published in 1992).

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

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

The branched tertiary alkyl group is not particularly limited, but for example, 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 a 1-methyl-2-propenyl group, a 2-methyl-3-butenyl group, a 4-methyl-2-hexenyl group and the like.

The alkoxy group is not particularly limited, and examples thereof include a hexyloxy group, a decyloxy group, and a dodecyloxy group.

The alkylcarbonyl group is not particularly limited, and examples thereof include a hexanoyl group, a decanoyl group, and a dodecanoyl group.

The alkoxycarbonyl group is not particularly limited, and examples thereof include a hexyloxycarbonyl group, a decyloxycarbonyl group, and a dodecyloxycarbonyl group.

The alkylthio group is not particularly limited, and examples thereof include a thiohexyl group, a thiodecyl group, and a thiododecyl group.

The above-mentioned chain aliphatic hydrocarbon group, alkoxy group, alkoxycarbonyl group, alkylcarbonyl group, and alkylthio group may further have a substituent. The substituent includes, but is not limited to, a chain aliphatic hydrocarbon group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, an alkylthio group or a halogen atom. The total number of carbon atoms and heteroatoms constituting the substituent is preferably 6 or less, preferably 4 or less, and particularly preferably 2 or less. Further, it may have two or more kinds of substituents.

^{Among these, R 1} and R ⁴ are monovalent organic groups, respectively, in order to prevent steric hindrance with adjacent naphthobisthiadiazole units from becoming large, maintain high π stackability, and improve conversion efficiency. It is preferable that R ² and R ³ are hydrogen atoms or halogen atoms. Further, the monovalent organic group is preferably a chain aliphatic hydrocarbon group which may have a substituent in order to improve the solubility of the copolymer. That is, a combination in which R ¹ and R ⁴ are chain aliphatic hydrocarbon groups which may have a substituent and R ² and R ³ are hydrogen atoms or halogen atoms is preferable. Among them, R ¹ and R ⁴ are chain aliphatic hydrocarbon groups having 4 to 30 carbon atoms which may have substituents, and R ² and R ³ are hydrogen atoms or halogen atoms. A combination is more preferable, in which R ¹ and R ⁴ are linear alkyl groups having 4 to 30 carbon atoms which may have substituents, and R ² and R ³ are hydrogen atoms or halogen atoms. It is particularly preferable that R ¹ and R ⁴ are linear alkyl groups having 8 or more and 20 or less carbon atoms.

In formula (I), D1 represents a donor component. The donor structural unit is a structural unit having a small ionization potential and a strong tendency to donate electrons, and is an aromatic group which may have a substituent. Specifically, the donor structural unit D1 is a structural unit having a smaller ionization potential and electron affinity than the naphthothiadiazole unit in the above formula (I). That is, in the present invention, the donor structural unit D1 is a structural unit having a higher HOMO energy level and a higher LUMO energy level than the naphthobisthiadiazole unit that functions as the acceptor structural unit in the above formula (I). .. The HOMO energy level and LUMO energy level of the acceptor component unit and the donor component unit are photoelectron yield spectroscopy (PYS) measurement, ultraviolet photoelectron spectroscopy (UPS) measurement, back light electron spectroscopy (IPES) measurement, and cyclic voltammetry measurement. In addition to being able to make an experimental estimate using the above, it can also be calculated by quantum chemical calculations such as the molecular orbital method (MO method) and the density half-function method (DFT method). When calculating the HOMO energy level and the LUMO energy level of the accepting structural unit and the donor structural unit, the terminal portion of each structural unit is replaced with a hydrogen atom.

Among them, in order to relax the rigidity of the copolymer and arrange the copolymers regularly, it is preferable that the donor structural unit D1 is a structural unit represented by the following formula (IV) or the following formula (V), respectively.

In formula (IV), Ar ⁵ and Ar ⁶ each independently represent an aromatic ring which may have a substituent. The aromatic ring represents an aromatic hydrocarbon ring or an aromatic heterocycle.

The aromatic hydrocarbon ring is not particularly limited, but an aromatic hydrocarbon ring having 6 or more and 30 or less carbon atoms constituting the ring is preferable. Specifically, monocyclic aromatic hydrocarbon rings such as benzene rings; condensed polycycles such as naphthalene ring, indan ring, inden ring, phenanthrene ring, fluorene ring, anthracene ring, azulene ring, pyrene ring, and perylene ring. The aromatic hydrocarbon ring of the formula can be mentioned. Of these, a benzene ring or a naphthalene ring is preferable.

The aromatic heterocycle is not particularly limited, but an aromatic heterocycle having 3 or more and 30 or less atoms constituting the ring is preferable. 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 fused polycyclic aromatic heterocycles such as a ring, a benzoxazole ring, a benzotriazole ring, and a thiadiazolopyridine ring. Of 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 are preferable.

The substituents that the aromatic hydrocarbon ring and the aromatic heterocycle may have are not particularly limited, and examples thereof include a halogen atom and a monovalent organic group. The number of carbon atoms constituting the monovalent organic group is not particularly limited, but is preferably 1 or more and 30 or less. Specific examples of the monovalent organic group include an aliphatic hydrocarbon group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, an alkylthio group, an aromatic hydrocarbon group, an aliphatic heterocyclic group or an aromatic heterocyclic group. Be done.

In the above formula (IV), X ³ and X ⁴ are independently Q ¹ (R ⁵ ) (R ⁶ ), Q ² (R ⁷ ), sulfur atom (S), oxygen atom (O) or directly. Represents a bond. However, when one of X ³ and X ⁴ is a direct bond, the other group of ^{X 3} and X ^{4 is Q 1} (R ⁵ ) (R ⁶ ), Q ² (R ⁷ ), sulfur atom ( S) or oxygen atom (O). Note that Q1 represents an atom selected from the Group 14 elements of the periodic table, and is preferably a carbon atom (C), a silicon atom (Si), or a germanium atom (Ge). Q ² represents an atom selected from the Group 15 elements of the periodic table, preferably a nitrogen atom (N) or a phosphorus atom (P).

R ⁵ and R ⁶ each ^{represent a group bonded to Q 1,} and independently represent a hydrogen atom, a halogen atom, or a monovalent organic group. In addition, R ⁵ and R ⁶ may be the same group or may be different groups from each other. Further, R ⁷ is a ^{group bonded to Q 2} and represents a hydrogen atom, a halogen atom or a monovalent organic group.

The monovalent organic group is not particularly limited, but is preferably an organic group having 1 or more and 30 or less carbon atoms. Among them, preferred groups include an aliphatic hydrocarbon group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, and an aliphatic complex which may have a substituent. It has a ring group, an aromatic heterocyclic group which may have a substituent, an alkoxy group which may have a substituent, an alkoxycarbonyl group which may have a substituent, and a substituent. Examples thereof include an alkylcarbonyl group which may have a substituent and an alkylthio group which may have a substituent.

The aliphatic hydrocarbon group is not particularly limited, and examples thereof include a chain aliphatic hydrocarbon group and a cyclic aliphatic hydrocarbon group. The chain-like aliphatic hydrocarbon group is not particularly limited, but preferred groups include the chain-like aliphatic hydrocarbon groups described in ^{R 1 to} R ^4.

The cyclic aliphatic hydrocarbon group is not particularly limited, but the number of carbon atoms is preferably 4 or more, preferably 6 or more, and on the other hand, 30 or less, preferably 20 or less. Is particularly preferable. Specific examples thereof include a cyclobutyl group, a cyclohexyl group, a cyclooctyl group, a cyclononyl 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 number of carbon atoms contained in the aromatic hydrocarbon group is preferably 6 or more, while it is preferably 30 or less, more preferably 20 or less, and particularly preferably 14 or less. Specific examples thereof include a phenyl group, a naphthyl group, an indanyl group, an indenyl group, a fluorenyl group, an anthrasenyl group, an azulenyl group and the like. Of these, a phenyl group is preferable.

The aliphatic heterocyclic group is not particularly limited, but the number of atoms constituting the ring is preferably 3 or more, while it is preferably 30 or less, more preferably 14 or less, and 10 or less. The following is particularly preferable. Specific examples thereof include an oxetanyl group, a pyrrolidinyl group, a tetrahydrofuryl group, a tetrahydrothienyl group, a piperidinyl group, a tetrahydropyranyl group or 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 aromatic heterocyclic group is not particularly limited, but the number of atoms constituting the ring is preferably 3 or more, while it is preferably 30 or less, more preferably 20 or less. It is particularly preferably 14 or less. Specifically, a thienyl group, a furanyl group, a pyridyl group, a pyrrolyl group, an imidazolyl group, a pyrimidyl group, a thiazolyl group, an oxazolyl group, an isooxazolyl group, an isothiazolyl group, a pyrazolyl group, a triazolyl group, a benzothiophenyl group, a benzofuranyl group and a benzothiazolyl group. Examples include groups, benzoxazolyl groups or benzotriazolyl groups. Among these, a thienyl group, a pyridyl group, a pyrimidyl group, a thiazolyl group or an oxazolyl group can be mentioned.

Preferred groups of the alkoxy group, the alkoxycarbonyl group, the alkylcarbonyl group and the alkylthio group include the groups listed in ^{R 1 to} R ^4.

The halogen atom is not particularly limited, and examples thereof include a fluorine atom.

The substituents that the aliphatic hydrocarbon group, the aromatic hydrocarbon group, the aliphatic heterocyclic group, the aromatic heterocyclic group, the alkoxy group, the alkoxycarbonyl group, the alkylcarbonyl group, and the alkylthio group may have are However, there are no particular restrictions, and examples thereof include an aromatic hydrocarbon group, an aliphatic heterocyclic group, an aromatic heterocyclic group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, an alkylthio group and a halogen atom.

A specific example of the structural unit represented by the formula (IV) is shown below. The structural unit represented by the formula (IV) is not limited to the following structural units.

In formula (V), Ar ⁷ and Ar ⁸ each independently represent an aromatic ring which may have a substituent. Examples of the aromatic ring include an aromatic hydrocarbon ring or an aromatic heterocycle. The substituents that the aromatic hydrocarbon ring, the aromatic heterocycle and the aromatic ring may have are not particularly limited, and for example, the aromatic hydrocarbon ring and the aromatic ring ^{mentioned in Ar 5} and Ar ^{6 above.} Heterocycles are mentioned, and so are preferred rings.

In the above formula (V), X ⁵ and X ⁶ each independently represent a group represented by ^{Q 3} (R ^8). Q ³ are represent the atoms selected from periodic table group 14 element, carbon atoms (C), silicon atoms (Si) or germanium atom (Ge) and the like.

R ⁸ represents a group bonded to Q ³ and represents a hydrogen atom, a halogen atom or a monovalent organic group. The monovalent organic group is not particularly limited, but is preferably a group having 1 or more and 30 or less carbon atoms. Specific examples of the monovalent organic group include an aliphatic hydrocarbon group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, and a substituent. It has an aliphatic heterocyclic group, an aromatic heterocyclic group which may have a substituent, an alkoxy group which may have a substituent, an alkoxycarbonyl group which may have a substituent, and a substituent. Examples thereof include an alkylcarbonyl group which may have a substituent, or an alkylthio group which may have a substituent. Specific examples of these groups include the groups listed in the ^{above-mentioned monovalent organic groups of R 5 to} R ^7. Further, as the substituents that these groups may have, the substituents described in the monovalent organic groups of ^{R 5 to} R ^{7 can be mentioned.}

A specific example of the structural unit represented by the equation (V) is shown below. The structural unit represented by the equation (V) is not limited to the following structural units.

Among these, the donor structural unit (D1) in the above formula (I) is preferably the donor structural unit represented by the above formula (V) in order to improve the conversion efficiency. Among them, the donor-based structural unit represented by the formula (V) is preferably the donor-based structural unit represented by the formula (III) in order to obtain higher conversion efficiency. In order to obtain higher conversion efficiency, the donor component represented by the formula (III) is preferably the donor component represented by the following formula (VI).

In formula (III), X ¹² and X ¹³ each independently represent an atom selected from the Group 16 elements of the Periodic Table. Specific examples thereof include an oxygen atom (O), a sulfur atom (S), a selenium atom (Se), and a tellurium atom (Te). Among them, X ¹² and X ¹³ are preferably sulfur atoms (S), respectively, because the copolymer exhibits good semiconductor properties.

In formula (III), R ⁹ and R ¹⁰ each independently include a hydrogen atom, a halogen atom, or a monovalent organic group. The monovalent organic group is not particularly limited, but is preferably a group having 1 or more and 30 or less carbon atoms. Specific examples of the monovalent organic group include an aliphatic hydrocarbon group which may have a substituent, an alkoxy group which may have a substituent, and an alkoxycarbonyl group which may have a substituent. , An alkylcarbonyl group which may have a substituent, an alkylthio group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, and a substituent which may have a substituent. Examples thereof include an aliphatic heterocyclic group or an aromatic heterocyclic group which may have a substituent. Specific examples of these groups include the groups listed in the ^{above-mentioned monovalent organic groups of R 5 to} R ^7. Further, as the substituents that these groups may have, the substituents described in the monovalent organic groups of ^{R 5 to} R ^{7 can be mentioned.} R ⁹ and R ¹⁰ may be the same group or different groups.

Among them, in order to improve the solubility, R ⁹ and R ¹⁰ have an aliphatic hydrocarbon group which may have a substituent independently and an aromatic hydrocarbon group which may have a substituent, respectively. Alternatively, it is preferably an aromatic heterocyclic group which may have a substituent. Among these, in order to extend the electron conjugate, it is preferable that R ⁹ and R ¹⁰ are aromatic heterocyclic groups which may independently have a substituent.

It is particularly preferable that the structural unit represented by the formula (III) is the structural unit represented by the following formula (VI).

Wherein (VI), R ⁹ and R ¹⁰ has the same meaning as R ⁹ and R ¹⁰ in formula (III).

Among them, in order to improve the solubility, R ⁹ and R ¹⁰ have an aliphatic hydrocarbon group which may have a substituent independently and an aromatic hydrocarbon group which may have a substituent, respectively. Alternatively, it is preferably an aromatic heterocyclic group which may have a substituent. Among them, in order to extend the electron conjugate, it is preferable that R ⁹ and R ¹⁰ are aromatic heterocyclic groups which may independently have a substituent. Aromatic heterocyclic groups include, but are not particular limitation, preferably, aromatic heterocyclic groups listed R ⁵ to R ^7. Among them, in order to improve the conversion efficiency, ^{it is particularly preferable that R 9} and R ¹⁰ are thienyl groups which may have substituents, respectively. The substituent is not particularly limited and may be a monovalent organic group. Specifically, the substituents described in the monovalent organic groups of ^{R 5 to} R ^{7 can be mentioned.} Among them, the substituent is preferably an aliphatic hydrocarbon group having 8 or more carbon atoms and 20 or less carbon atoms, and particularly preferably an alkyl group having 8 or more carbon atoms and 20 or less carbon atoms.

As described above, the copolymer according to the first aspect of the present invention has a repeating unit represented by the following formula (II) in addition to the repeating unit represented by the above formula (I).

In the above formula (II), Ar ³ and Ar ⁴ each independently represent an aromatic group which may have a substituent. Examples of the aromatic group include an aromatic hydrocarbon group and an aromatic heterocyclic group. Among these, Ar ³ and Ar ⁴ are preferably groups having a high degree of freedom of rotation with respect to adjacent constituent units. If Ar ³ and Ar ⁴ are groups with a high degree of freedom of rotation, the rigidity of the copolymer can be relaxed, so that the copolymers can be arranged regularly and the conversion efficiency can be improved. For this reason, Ar ³ and Ar ⁴ are preferably groups whose three-dimensional structure is not too large, and specifically, they are preferably aromatic groups in which the number of atoms constituting the aromatic ring is 14 or less. It is more preferable that the aromatic group has 10 or less atoms constituting the aromatic ring, and the aromatic group has 8 or less atoms constituting the aromatic ring in order to improve the solubility. Is particularly preferable. On the other hand, the number of atoms constituting the aromatic ring is usually 3 or more, and is particularly preferably 5 or more in order to improve carrier mobility. Examples of the aromatic hydrocarbon group include a phenyl group and a naphthyl group. Examples of the aromatic heterocyclic group include a thienyl group (thiophene), a furanyl group (furan), a thiazolyl group, a thienotienyl group, a thienofuranyl group or a thienophenyl. Further, the substituent that the aromatic group may have is not particularly limited, and examples thereof include monovalent organic groups. The monovalent organic group is not particularly limited, but when improving the solubility of the copolymer, it is preferably a group having 6 or more carbon atoms, more preferably 10 or more carbon atoms, while adjacent constituent units. In order to prevent the steric hindrance from becoming large, it is preferably 20 or less, and particularly preferably 16 or less.

The monovalent organic group is not particularly limited, and examples thereof include a chain aliphatic hydrocarbon group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, and an alkylthio group, and among these, a chain fat. It is preferably a group hydrocarbon group. In addition, these groups may further have a substituent. The substituent is not particularly limited, and examples thereof include the groups listed in the monovalent organic group. The monovalent organic group described above may have a plurality of substituents within a substitutable range. Further, it may have two or more kinds of substituents.

In the above formula (II), c and d represent integers of 0 or more and 2 or less, respectively. When c is 2, two ^{groups represented by Ar 3} are linked. In this case, the ^{groups represented by two Ar 3} may be the same group or different groups. Good. Similarly, when d is 2, two ^{groups represented by Ar 4} are linked, but in this case, the ^{groups represented by two Ar 4} may be the same group or different groups. May be good. Among these, it is preferable that both c and d are 1 in order to exhibit a point where the solubility of the copolymer can be adjusted, a point where the crystallinity can be adjusted, and good semiconductor characteristics.

Among these, the repeating unit represented by the above formula (II) is preferably a structural unit represented by the following formula (VII).

In formula (VII), X ⁷ and X ⁸ represent atoms selected from Group 16 elements of the periodic table, respectively, and specifically, oxygen atom (O), sulfur atom (Si), selenium atom (Se) or selenium atom (Se). The tellul atom (Te) can be mentioned. Among them, a sulfur atom (S) is preferable in order to improve the semiconductor characteristics.

In formula (VII), R ^{11 to} R ¹⁴ independently represent a hydrogen atom, a halogen atom or a monovalent organic group. The monovalent organic group is not particularly limited, but has a chain aliphatic hydrocarbon group which may have a substituent, an alkoxy group which may have a substituent, and a substituent. Examples thereof include an alkoxycarbonyl group, an alkylcarbonyl group which may have a substituent, and an alkylthio group which may have a substituent. Specific examples of these groups include the groups listed in ^{R 1 to} R ^4. Among these, in order to prevent deterioration of semiconductor characteristics, R ^{11 to} R ¹⁴ are preferably hydrogen atoms, halogen atoms or chain aliphatic hydrocarbon groups. Further, when A in the formula (VII) is a structural unit represented by the formula (VIII) described later or a structural unit represented by the formula (IX), each structural unit can be easily arranged on the same plane. ^{11 to} R ¹⁴ are preferably hydrogen atoms, halogen atoms or aliphatic hydrocarbon groups having 1 or more and 3 or less carbon atoms, and more preferably hydrogen atoms or aliphatic hydrocarbon groups having 1 or more and 3 or less carbon atoms. .. Further, when A in the formula (II) is not a direct bond, R ² and R ³ in the formula (I) are hydrogen atoms, respectively, and R ¹ and R ⁴ are monovalent organic groups, the appropriateness of the copolymer is also suitable. R ^{11 to} R ¹⁴ are preferably hydrogen atoms, halogen atoms or aliphatic hydrocarbon groups having 1 or more and 3 or less carbon atoms, and hydrogen atoms or aliphatic hydrocarbons having 1 or more and 3 carbon atoms or less. It is more preferably a hydrogen group. Examples of the aliphatic hydrocarbon group having 1 or more and 3 or less carbon atoms include an alkyl group, more preferably a methyl group or an ethyl group, and further preferably a methyl group.
In these cases, one of R ¹¹ and R ¹² is a hydrogen atom, the other is an aliphatic hydrocarbon group having 1 or more and 3 or less carbon atoms, one of R ¹³ and R ¹⁴ is a hydrogen atom, and the other is carbon. A combination of 1 or more and 3 or less aliphatic hydrocarbon groups is more preferable, and R ¹¹ and R ¹⁴ are aliphatic hydrocarbon groups having 1 or more and 3 or less carbon atoms, and R ¹² and R ¹³ are hydrogen atoms. Is particularly preferable. When A is a direct bond, R ^{11 to} R ¹⁴ are preferably hydrogen atoms or halogen atoms. The halogen atom is preferably a fluorine atom.

In formulas (II) and (VII), D2 represents a donor component, similar to D1 in formulas (I) and III. That is, D2 is a structural unit having a higher HOMO energy level and a higher LUMO energy level than the acceptable structural unit (A) in the formula (II), and is an aromatic group that may have a substituent. is there. The HOMO energy level and the LUMO energy level can be measured by the methods listed in the item of donor constitutive unit D1.

The donor structural unit D2 is not particularly limited, but like the donor structural unit D1, it is preferably a structural unit represented by the above formula (IV) or a structural unit represented by the above formula (V). , The structural unit represented by the above formula (V) is more preferable, and the structural unit represented by the above formula (VI) is particularly preferable. It should be noted that D1 and D2 may be the same structural unit or different structural units, respectively, but in order to match the energy band gaps of the units contained in the copolymer and maintain good charge separation. It is preferable that D1 and D2 are the same structural unit.

In the above formulas (II) and (VII), A represents an accepting structural unit or a direct bond. In formula (II), when A is a direct bond, c and d in formula (II) are 1 or 2, respectively. When A is a direct bond, the fact that c and d are 1 or 2 causes − (Ar ³ ) _c − (Ar ⁴ ) _d − to function as an acceptor building unit. In the present invention, the acceptor-like structural unit is a structural unit having a high electron affinity and a strong tendency to accept electrons, and examples thereof include aromatic groups that may have a substituent. Specifically, the acceptor-like structural unit A is a structural unit having a larger ionization potential and electron affinity than the donor-like structural unit D2. That is, in the present invention, the acceptable structural unit is a structural unit having a lower HOMO energy level and a lower LUMO energy level than the donor structural unit D2. The HOMO energy level and the LUMO energy level can be measured by the method described in the item of donor constitutional unit D1.

Among them, the acceptable structural unit is preferably a structural unit different from the naphthithiadiazole unit in the formula (I) from the viewpoint of photoelectric conversion efficiency. The reason for this is that the acceptable structural unit (A) is a structural unit different from the naphthothiadiazole unit in the formula (I), so that the energy band gap and the absorption wavelength can be adjusted, so that light can be efficiently used. This is because absorption becomes possible, and as a result, the conversion efficiency of the photoelectric conversion element is improved.

Among these, the acceptable structural unit (A) is preferably a structural unit represented by the following formula (VIII) or the following formula (IX).

In formula (VIII), Ar ⁹ is an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocycle which may have a substituent, or a fat which may have a substituent. Represents a group heterocycle.

The aromatic hydrocarbon ring and the aromatic heterocycle are not particularly limited, and examples thereof include the aromatic hydrocarbon ring and the aromatic heterocycle ^{mentioned in Ar 5} and Ar ^{6 described above.} Of 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 are preferable.

The aliphatic heterocycle is not particularly limited, but is preferably an aliphatic heterocycle in which the number of atoms constituting the ring is 4 or more and 8 or less. Specific examples thereof include a pyrrolidine ring or a piperidine ring.

The substituents that the aromatic hydrocarbon ring, the aromatic heterocycle and the aliphatic heterocycle may have are not particularly limited, and examples thereof include monovalent organic groups. The monovalent organic group is not particularly limited, and is an aliphatic hydrocarbon group, an aromatic hydrocarbon group, an aliphatic heterocyclic group, an aromatic heterocyclic group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, or an alkylthio. The group is mentioned.

In the above formula (VIII), X ⁹ and X ¹⁰ independently represent a nitrogen atom (N) or Q ⁴ (R ¹⁵ ). Q ⁴ are represent the atoms selected from periodic table group 14 element, and among them, preferably a carbon atom (C). Further, R ¹⁵ represents a group bonded to Q ⁴ and represents a hydrogen atom, a halogen atom or a monovalent organic group. The monovalent organic group is not particularly limited and has an aliphatic hydrocarbon group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, and a substituent. May be an aliphatic heterocyclic group, an aromatic heterocyclic group which may have a substituent, an alkoxy group which may have a substituent, an alkoxycarbonyl group which may have a substituent, and a substituent. Examples thereof include an alkylcarbonyl group which may have a substituent, or an alkylthio group which may have a substituent. Specifically, the groups listed in ^{R 5 to} R ^{7 described above can be mentioned.}

An example of the structural unit represented by the formula (VIII) is shown below. The structural unit represented by the formula (VIII) is not limited to the following.

In the above formula (IX), Ar ¹⁰ may have an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocycle which may have a substituent, or a substituent. Represents an aliphatic heterocycle. The aromatic hydrocarbon ring, aromatic heterocycle, and aliphatic heterocycle are not particularly limited, but specifically, the aromatic hydrocarbon ring, aromatic heterocycle, and aliphatic heterocycle mentioned ^{in Ar 9 are used.} Can be mentioned. The substituents that the aromatic hydrocarbon ring, the aromatic heterocycle and the aliphatic heterocycle may have are not particularly limited, and specifically, the aromatic hydrocarbon ring mentioned ^{in Ar 9} Examples thereof include substituents similar to the substituents that the aromatic heterocycle and the aliphatic heterocycle may have.

In the above formula (IX), X ¹¹ represents an atom selected from the elements of Group 16 of the periodic table, and specifically, an oxygen atom (O), a sulfur atom (S), a selenium atom (Se), or a tellurium atom ( Te) can be mentioned. ^{Among them, X 11} is preferably a sulfur atom in order to improve the semiconductor characteristics.

An example of the structural unit represented by the formula (IX) is shown below. The structural unit represented by the formula (IX) is not limited to the following.

Among these, the acceptable structural unit (A) is preferably the structural unit represented by the formula (VIII), and in order to improve the conversion efficiency, it is the structural unit represented by the following formula (X). Is particularly preferred.

In the above formula (X), R ¹⁶ and R ¹⁷ represent a hydrogen atom, a halogen atom or a monovalent organic group. The monovalent organic group is not particularly limited, but has an aliphatic hydrocarbon group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, and a substituent. May be an aliphatic heterocyclic group, an aromatic heterocyclic group which may have a substituent, an alkoxy group which may have a substituent, an alkoxycarbonyl group which may have a substituent, and a substituent. Examples thereof include an alkylcarbonyl group which may have a substituent, or an alkylthio group which may have a substituent. Specific examples of these include the groups listed in ^{R 5 to} R ^7. Among these, R ¹⁶ and R ¹⁷ are preferably chain aliphatic hydrocarbon groups or halogen atoms having 1 or more and 20 or less carbon atoms, respectively. Among them, it is particularly preferable that both ^{R 16} and R ¹⁷ are fluorine atoms in order to strengthen the packing between the polymer main chains by the interaction between dipoles and to adjust the energy gap by the effect of electron attraction. ..

Among the above, D1 in the formula (I) is a repeating unit represented by the formula (VI), A in the formula (II) is a repeating unit represented by the formula (X), and D2 is a repeating unit represented by the formula (X). A combination that is a repeating unit represented by VI) is preferable.

The copolymer containing the repeating unit represented by the formula (I) and the formula (II) according to the first aspect of the present invention is the repeating unit represented by the formula (I) and the repeating unit represented by the formula (II). May be contained one by one, and either one or both may be contained in two or more kinds.
Further, the copolymer according to the first aspect of the present invention is 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 effect of the present invention is not impaired. It may have a unit. The other repeating unit is not particularly limited, and examples thereof include the acceptor-type structural unit and the donor-type structural unit described above.

In the copolymer according to the first aspect of the present invention, the arrangement states of the repeating unit represented by the above formula (I) and the repeating unit represented by the above formula (II) and other repeating units are alternately blocked. Or it may be random. That is, the copolymer according to the first aspect of the present invention may be either an alternating copolymer, a block copolymer or a random copolymer. Further, among these copolymers, a copolymer having an intermediate structure, for example, a random copolymer having a blocking property may be used. Also included are copolymers with branches in the main chain and three or more ends, and dendrimers. Among them, block copolymers or random copolymers are preferable because they are easy to synthesize and the regularity can be further reduced, and the solubility of the copolymer is improved and the storage stability of the ink in which the copolymer is dissolved is improved. Random copolymers are more preferred in that they can.

The terminal portion of the copolymer according to the first aspect of the present invention is not particularly limited, but is preferably end-gap with an aromatic hydrocarbon ring, an aromatic heterocycle, or a hydrogen atom.

In the copolymer according to the first aspect of the present invention, the ratio (I / II) of the number of repeating units represented by the above formula (I) to the number of repeating units represented by the above formula (II) is not particularly limited. , 0.1 or more, preferably 0.2 or more, in order to maintain the energy band gap of the structural unit represented by the formula (I), absorb in the long wavelength region, and adjust the solubility of the copolymer. Is more preferable, and 0.3 or more is particularly preferable. On the other hand, the ratio of the number of repeating units represented by the above formula (I) to the number of repeating units represented by the above formula (II) adjusts the energy band gap of the polymer, widens the absorption region, and the main chain. In order to change the rotation barrier and flatness of the main chain and adjust the interaction between the main chains, the value is preferably 9 or less, more preferably 4 or less, further preferably 3 or less, and 2.3. The following is particularly preferable.

Among the copolymers according to the first aspect of the present invention, the repeating units represented by the above formula (I) and the repeating units represented by the above formula (II) with respect to the total number of repeating units constituting the copolymer according to the first aspect of the present invention. The ratio of the total number of units (the ratio of the total number of repeating units represented by the formula (I) and the total number of repeating units represented by the formula (II) to the total number of constituent units constituting the copolymer) is not particularly limited. However, in order to obtain good semiconductor characteristics, it is preferably 0.1 or more, more preferably 0.3 or more, and particularly preferably 0.5 or more. On the other hand, the upper limit is 1.

Particularly preferably, does the copolymer according to the first aspect of the present invention contain a repeating unit represented by the formula (I) and a repeating unit represented by the formula (II), and is composed only of these repeating units? , Or a polymer chain containing these repeating units and consisting only of these repeating units.

<1-2. Copolymer according to the second aspect of the present invention>
The copolymer according to another embodiment of the present invention (the copolymer according to the second aspect) has a structural unit represented by the following formula (I).

In formula (I), X ¹ and X ² each independently represent an atom selected from the Group 16 elements of the Periodic Table. Specific examples thereof include an oxygen atom (O), a sulfur atom (S), a selenium atom (Se), and a tellurium atom (Te). Among them, X ¹ and X ² are preferably sulfur atoms (S), respectively, in order to improve the semiconductor properties of the copolymer.

In formula (I), R ¹ and R ⁴ are independent of each other and have a linear aliphatic hydrocarbon group having 9 or more carbon atoms or a main chain having 9 or more carbon atoms and a side chain having 9 or more carbon atoms. Represents a branched aliphatic hydrocarbon group having a value of 5 or less. In the present invention, the main chain in the branched aliphatic hydrocarbon group means the carbon chain having the maximum number of carbon atoms in the branched aliphatic hydrocarbon group. The side chain means a carbon chain portion branched from the main chain. Further, in the present invention, the carbon number of the side chain of 5 or less means that when the branched aliphatic hydrocarbon group has a plurality of side chains, the carbon number of each side chain is 5 or less. ..
Highly soluble copolymers are obtained when R ¹ and R ⁴ are linear aliphatic hydrocarbon groups having 9 or more carbon atoms or branched aliphatic hydrocarbon groups having 9 or more carbon atoms in the main chain. Furthermore, it is considered that the conversion efficiency of the photoelectric conversion element can be improved by the conjugate structure of the copolymer and the interaction between the main chains in the active layer of the photoelectric conversion element. In order to further enhance the solubility and interaction of the polymer, the number of carbon atoms of the linear aliphatic hydrocarbon group is more preferably 10 or more, further preferably 12 or more, and 13 or more. Is particularly preferred. Similarly, the number of carbon atoms in the main chain of the branched aliphatic hydrocarbon group is more preferably 10 or more, further preferably 12 or more, and particularly preferably 13 or more.

On the other hand, the upper limit of the carbon number of the linear aliphatic hydrocarbon group and the carbon number of the main chain of the branched aliphatic hydrocarbon group is not particularly limited, but R ^{1 while maintaining high solubility.} In ^{order to prevent steric hindrance between the 5-membered ring having R 4} and the donor constituent unit represented by D1 in the adjacent formula (I) and to maintain the flatness of the copolymer, the carbon number is set. It is preferably 25 or less, more preferably 20 or less, and particularly preferably 16 or less. By maintaining the flatness of the copolymer, the copolymers tend to be arranged regularly in the active layer of the photoelectric conversion element, and high conversion efficiency tends to be obtained.

Further, when R ¹ and / or R ⁴ is a branched aliphatic hydrocarbon group, the number of carbon atoms in the side chain is set to 5 or less, so that the five members having ^{R 1} and R ^{4 in the formula (I) are used.} Steric hindrance with the donor structural unit represented by D1 in the formula (I) adjacent to the ring is less likely to occur, and the flatness of the copolymer is easily obtained. Therefore, the copolymers can be easily arranged regularly in the active layer, and the conversion efficiency of the photoelectric conversion element can be improved. In addition, in order to further reduce the steric hindrance with the donor structural unit, the number of carbon atoms in the side chain is more preferably 4 or less, and further preferably 2 or less.

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

Specific examples of the linear alkyl group include a decyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, an icosyl group and the like.

Specific examples of the linear alkenyl group include a decenyl group, a dodecenyl group, a tridecenyl group, a tetradecenyl group, a pentadecenyl group, a hexadecenyl group and the like.

Specific examples of the linear alkynyl group include a decynyl group, a dodecynyl group, a tridecynyl group, a tetradecynyl group, a pentadecynyl group, a hexadecynyl group and the like.

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 an ethyldecyl group, an ethyldodecyl group, an ethylpentadecyl group, a 2,6-dimethyldecyl group, a 2,6-dimethyldodecyl group and the like.

Examples of the branched alkenyl group include an ethyldecenyl group, an ethyldodecenyl group, an ethylpentadecenyl group, a 2,6-dimethyldecenyl group, a 2,6-dimethyldodecenyl group and the like.

Examples of the branched alkynyl group include an ethyldecynyl group, an ethyldodecynyl group, an ethylpentadecynyl group, a 2,6-dimethyldecynyl group, a 2,6-dimethyldodecynyl group and the like.

Among these, the aliphatic hydrocarbon group is preferably a linear aliphatic hydrocarbon group in order to maintain the flatness of the polymer.

In addition, a part or all hydrogen atoms contained in an aliphatic hydrocarbon group may be substituted with a fluorine atom. In the present invention, an aliphatic hydrocarbon group in which some or all hydrogen atoms are substituted with fluorine atoms is also regarded as an aliphatic hydrocarbon group.

In formula (I), R ² and R ³ independently represent a hydrogen atom or a halogen atom, respectively. When R ² and R ³ are hydrogen atoms or halogen atoms, it is possible to suppress the occurrence of steric hindrance between the ^{5-membered ring having R 2} and the 5-membered ring ^{having R 3 and the adjacent naphthithiadiazole unit.} , Copolymers can be regularly arranged in the active layer of the photoelectric conversion element. Among them, ^{both R 2} and R ³ are preferably hydrogen atoms or fluorine atoms, and more preferably both hydrogen atoms.

In formula (I), D1 represents a donor component. The donor structural unit is a structural unit having a small ionization potential and a strong tendency to donate electrons, and is an aromatic group which may have a substituent. Specifically, the donor structural unit D1 is a structural unit having a smaller ionization potential and electron affinity than the naphthothiadiazole unit in the formula (I). That is, in the present invention, the donor structural unit D1 is a structural unit having a higher HOMO energy level and a higher LUMO energy level than the naphthobisthiadiazole unit in the formula (I). The HOMO energy level and LUMO energy level of the naphthobistiaziazole unit and the donor component unit are photoelectron yield spectroscopy (PYS) measurement, ultraviolet photoelectron spectroscopy (UPS) measurement, back light electron spectroscopy (IPES) measurement, and cyclic voltammetry measurement. It can be estimated experimentally by such means. In addition, the HOMO energy level and LUMO energy level of the naphthobistiaziazole unit and the donor constituent unit can be calculated by quantum chemistry calculations such as the molecular orbital method (MO method) and the density semi-functional method (DFT method). .. When calculating the HOMO energy level and LUMO energy level of the naphthobisthiadiazole unit and the donor component unit, the terminal portion of each component unit is replaced with a hydrogen atom.

Among them, in order to relax the rigidity of the copolymer and arrange the copolymers regularly, it is preferable that the donor structural unit D1 is a structural unit represented by the following formula (IV) or the following formula (V), respectively.

In formula (IV), Ar ⁵ and Ar ⁶ each independently represent an aromatic ring which may have a substituent. The aromatic ring represents an aromatic hydrocarbon ring or an aromatic heterocycle.

The number of carbon atoms constituting the aromatic hydrocarbon ring is preferably 6 or more and 30 or less. Specifically, monocyclic aromatic hydrocarbons such as benzene rings; fused polycyclics such as naphthalene ring, indan ring, inden ring, phenanthrene ring, fluorene ring, anthracene ring, azulene ring, pyrene ring, and perylene ring. Aromatic hydrocarbons can be mentioned. Of these, a benzene ring or a naphthalene ring is preferable.

The sum of the numbers of carbon atoms and heteroatoms constituting the ring of the aromatic heterocycle is preferably 3 or more and 30 or less. Examples of the hetero atom include a nitrogen atom, an oxygen atom, a sulfur atom and the like. Specific examples of the aromatic heterocycle include a monocyclic aromatic heterocycle such as a thiophene ring, a furan ring, a pyridine ring, a pyrimidine ring, a thiazole ring, an oxazole ring, and a triazole ring; or a thienothiophene ring or a benzothiophene ring. Examples thereof include fused polycyclic aromatic heterocycles such as a ring, a benzofuran ring, a benzothiazole ring, a benzoxazole ring, a benzotriazole ring, and a thiadiazolopyridine ring. Of 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 are preferable.

The substituents that the aromatic hydrocarbon ring and the aromatic heterocycle may have are not particularly limited, and examples thereof include a halogen atom and a monovalent organic group. The number of carbon atoms of the monovalent organic group is not particularly limited, but is preferably 1 or more and 30 or less. Specific examples of the monovalent organic group include an aliphatic hydrocarbon group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, an alkylthio group, an aromatic hydrocarbon group, an aliphatic heterocyclic group or an aromatic heterocyclic group. Be done.

In the above formula (IV), X ³ and X ⁴ are independently Q ¹ (R ⁵ ) (R ⁶ ), Q ² (R ⁷ ), sulfur atom (S), oxygen atom (O) or directly. Represents a bond. However, when one of X ³ and X ⁴ is a direct bond, the other group of ^{X 3} and X ^{4 is Q 1} (R ⁵ ) (R ⁶ ), Q ² (R ⁷ ), sulfur atom ( S) or oxygen atom (O). Note that Q ¹ represents an atom selected from the Group 14 elements of the periodic table, and is preferably a carbon atom (C), a silicon atom (Si), or a germanium atom (Ge). Q ² represents an atom selected from the Group 15 elements of the periodic table, preferably a nitrogen atom (N).

R ⁵ and R ⁶ each ^{represent a group bonded to Q 1,} and independently represent a hydrogen atom, a halogen atom, or a monovalent organic group. R ⁵ and R ⁶ may be the same group or different groups from each other. R ⁷ is a ^{group bonded to Q 2} and represents a hydrogen atom, a halogen atom or a monovalent organic group.

The monovalent organic group is not particularly limited, but is preferably a group having 1 or more and 30 or less carbon atoms. Specific examples of the monovalent organic group include an aliphatic hydrocarbon group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, and a substituent. It has an aliphatic heterocyclic group, an aromatic heterocyclic group which may have a substituent, an alkoxy group which may have a substituent, an alkoxycarbonyl group which may have a substituent, and a substituent. Examples thereof include an alkylcarbonyl group which may have a substituent, or an alkylthio group which may have a substituent.

The aliphatic hydrocarbon group is not particularly limited, and examples thereof include a chain aliphatic hydrocarbon group and a cyclic aliphatic hydrocarbon group.

The carbon number of the chain aliphatic hydrocarbon group is preferably 4 or more, more preferably 6 or more in order to improve the solubility of the copolymer, and 30 or less in order to avoid steric hindrance. It is preferably present, and more preferably 20 or less.

Examples of the chain-shaped aliphatic hydrocarbon group include a linear aliphatic hydrocarbon group and a branched aliphatic hydrocarbon group.

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 an n-butyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-decyl group or an n-dodecyl group.

The linear alkenyl group is not particularly limited, and examples thereof include a 5-hexenyl group, a 7-octynyl group, and an 11-dodecenyl 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 one that can form a bond with another free valence as described in the Organic Chemistry / Biochemical Nomenclature (above) (Revised 2nd Edition, Nankodo, published in 1992).

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

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

The branched tertiary alkyl group is not particularly limited, but for example, 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 a 1-methyl-2-propynyl group, a 2-methyl-3-butynyl group, and a 4-methyl-2-hexynyl group.

The number of carbon atoms of the cyclic aliphatic hydrocarbon group is not particularly limited, but is preferably 4 or more, preferably 6 or more, and on the other hand, preferably 30 or less, and preferably 20 or less. Is particularly preferable. Specific examples thereof include a cyclobutyl group, a cyclohexyl group, a cyclooctyl group, a cyclononyl group and the like.

The number of carbon atoms of the alkoxy group is not particularly limited, but is preferably 4 or more, preferably 6 or more, while preferably 30 or less, and particularly preferably 20 or less. Specific examples thereof include a hexyloxy group, a decyloxy group and a dodecyloxy group.

The number of carbon atoms of the alkylcarbonyl group is not particularly limited, but is preferably 4 or more, preferably 6 or more, while preferably 30 or less, and particularly preferably 20 or less. Specific examples thereof include a hexanoyl group, a decanoyle group, and a dodecanoyl group.

The number of carbon atoms of the alkoxycarbonyl group is not particularly limited, but is preferably 4 or more, preferably 6 or more, while preferably 30 or less, and particularly preferably 20 or less. Specific examples thereof include a hexyloxycarbonyl group, a decyloxycarbonyl group and a dodecyloxycarbonyl group.

The number of carbon atoms of the alkylthio group is not particularly limited, but is preferably 4 or more, preferably 6 or more, while preferably 30 or less, and particularly preferably 20 or less. Specific examples thereof include a thiohexyl group, a thiodecyl group, and a thiododecyl group.

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 number of carbon atoms of the aromatic hydrocarbon group is not particularly limited, but is preferably 6 or more, while it is preferably 30 or less, more preferably 20 or less, and preferably 14 or less. Especially preferable. Specific examples thereof include a phenyl group, a naphthyl group, an indanyl group, an indenyl group, a fluorenyl group, an anthrasenyl group, an azulenyl group and the like.

The aliphatic heterocyclic group is not particularly limited, but the number of atoms constituting the ring is preferably 3 or more, while it is preferably 30 or less, more preferably 14 or less, and 10 or less. The following is particularly preferable. The atoms constituting the ring are not particularly limited, and examples thereof include carbon atoms, nitrogen atoms, oxygen atoms, and sulfur atoms. Specific examples thereof include an oxetanyl group, a pyrrolidinyl group, a tetrahydrofuryl group, a tetrahydrothienyl group, a piperidinyl group, a tetrahydropyranyl group or 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 aromatic heterocyclic group is not particularly limited, but the number of atoms constituting the ring is preferably 3 or more, while it is preferably 30 or less, more preferably 20 or less. It is particularly preferably 14 or less. The atoms constituting the ring are not particularly limited, and examples thereof include carbon atoms, nitrogen atoms, oxygen atoms, and sulfur atoms. Specifically, a thienyl group, a furanyl group, a pyridyl group, a pyrrolyl group, an imidazolyl group, a pyrimidyl group, a thiazolyl group, an oxazolyl group, an isooxazolyl group, an isothiazolyl group, a pyrazolyl group, a triazolyl group, a benzothiophenyl group, a benzofuranyl group and a benzothiazolyl group. Examples include groups, benzoxazolyl groups or benzotriazolyl groups. Among these, a thienyl group, a pyridyl group, a pyrimidyl group, a thiazolyl group or an oxazolyl group can be mentioned.

The halogen atom is not particularly limited, and examples thereof include a fluorine atom.

It should be noted that the substituents that the aliphatic hydrocarbon group, the alkoxy group, the alkoxycarbonyl group, the alkylcarbonyl group, and the alkylthio group, the aromatic hydrocarbon group, the aliphatic heterocyclic group and the aromatic heterocyclic group may have. Is not particularly limited, for example, an aliphatic hydrocarbon group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, and an alkylthio group, an aromatic hydrocarbon group, an aliphatic heterocyclic group, an aromatic heterocyclic group and a halogen. Examples include atoms.

A specific example of the structural unit represented by the formula (IV) is shown below. The structural unit represented by the formula (IV) is not limited to the following structural units.

In formula (V), Ar ⁷ and Ar ⁸ each independently represent an aromatic ring which may have a substituent. Examples of the aromatic ring include an aromatic hydrocarbon ring or an aromatic heterocycle. The aromatic hydrocarbon ring and the aromatic heterocycle are not particularly limited, and examples thereof include the aromatic hydrocarbon ring and the aromatic heterocycle ^{mentioned in Ar 5} and Ar ^{6 described above, and the same applies to preferred rings.} ..

In the above formula (V), X ⁵ and X ⁶ each independently represent a group represented by ^{Q 3} (R ^8). Q ³ are represent the atoms selected from periodic table group 14 element, carbon atoms (C), silicon atoms (Si) or germanium atom (Ge) and the like.

R ⁸ represents a group bonded to Q ³ and represents a hydrogen atom, a halogen atom or a monovalent organic group. The monovalent organic group is not particularly limited, but is preferably an organic group having 1 or more and 30 or less carbon atoms. Specific examples of the monovalent organic group include an aliphatic hydrocarbon group which may have a substituent, an alkoxy group which may have a substituent, and an alkoxycarbonyl group which may have a substituent. , An alkylcarbonyl group which may have a substituent, an alkylthio group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, and a substituent which may have a substituent. Examples thereof include an aliphatic heterocyclic group or an aromatic heterocyclic group which may have a substituent. Specific examples of these groups include the groups listed in the ^{above-mentioned monovalent organic groups of R 5 to} R ^7. Further, as the substituents that these groups may have, the substituents described in the monovalent organic groups of ^{R 5 to} R ^{7 can be mentioned.}

A specific example of the structural unit represented by the equation (V) is shown below. The structural unit represented by the equation (V) is not limited to the following structural units.

Among these, the donor structural unit (D1) in the above formula (I) is preferably the donor structural unit represented by the above formula (V) in order to improve the conversion efficiency. Among them, the donor-based structural unit represented by the formula (V) is preferably the donor-based structural unit represented by the following formula (III) in order to obtain higher conversion efficiency.

In formula (III), X ¹² and X ¹³ each independently represent an atom selected from the Group 16 elements of the Periodic Table. Specific examples thereof include an oxygen atom (O), a sulfur atom (S), a selenium atom (Se), and a tellurium atom (Te). Among them, X ¹² and X ¹³ are preferably sulfur atoms (S), respectively, because the copolymer exhibits good semiconductor properties.

In formula (III), R ⁹ and R ¹⁰ each independently include a hydrogen atom, a halogen atom, or a monovalent organic group. The monovalent organic group is not particularly limited, but is preferably an organic group having 1 or more and 30 or less carbon atoms. Specific examples of the monovalent organic group include an aliphatic hydrocarbon group which may have a substituent, an alkoxy group which may have a substituent, and an alkoxycarbonyl group which may have a substituent. , An alkylcarbonyl group which may have a substituent, an alkylthio group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, and a substituent which may have a substituent. Examples thereof include an aliphatic heterocyclic group or an aromatic heterocyclic group which may have a substituent. Specific examples of these groups include the groups listed in the ^{above-mentioned monovalent organic groups of R 5 to} R ^7. Further, as the substituents that these groups may have, the substituents described in the monovalent organic groups of ^{R 5 to} R ^{7 can be mentioned.} R ⁹ and R ¹⁰ may be the same group or different groups.

Among them, in order to improve the solubility, R ⁹ and R ¹⁰ have an aliphatic hydrocarbon group which may have a substituent independently and an aromatic hydrocarbon group which may have a substituent, respectively. Alternatively, it is preferably an aromatic heterocyclic group which may have a substituent.

Among these, in order to extend the electron conjugate, it is preferable that R ⁹ and R ¹⁰ are aromatic heterocyclic groups which may independently have a substituent. Among them, the structural unit represented by the formula (III) is particularly preferably the structural unit represented by the following formula (XV).

Wherein (XV), X ¹² and X ¹³ has the same meaning as X ¹² and X ¹³ in formula (III). Further, X ¹⁴ and X ¹⁵ each independently represent an atom selected from the Group 16 elements of the periodic table. That is, X ^{12 to} X ¹⁵ independently represent atoms selected from the elements of Group 16 of the periodic table. Specific examples of the atom selected from the elements of Group 16 of the periodic table include an oxygen atom (O), a sulfur atom (S), a selenium atom (Se), and a tellurium atom (Te). Among them, X ^{12 to} X ¹⁵ are preferably sulfur atoms (S), respectively, because the copolymer exhibits good semiconductor properties.

R ^{20 to} R ²⁵ represent hydrogen atoms, halogen atoms or monovalent organic groups, respectively.

The monovalent organic group is not particularly limited, but is preferably an organic group having 1 or more and 30 or less carbon atoms. Specific examples of the monovalent organic group include a chain aliphatic hydrocarbon group having 1 to 30 carbon atoms which may have a substituent and 1 to 30 carbon atoms which may have a substituent. It has the following alkoxy group, an alkoxycarbonyl group having 1 to 30 carbon atoms which may have a substituent, an alkylcarbonyl group having 1 to 30 carbon atoms which may have a substituent, or a substituent. Examples thereof include an alkylthio group having 1 or more and 30 or less carbon atoms which may be used. Specific examples of these groups include the chain aliphatic hydrocarbon group, alkoxy group, alkoxycarbonyl group, alkylcarbonyl group, and alkylthio group ^{mentioned in R 5 to} R ^{7 described above.}

Among these, in order to reduce steric hindrance, ^{it is preferable that one group of R 20 to} R ²² is a monovalent organic group and the remaining two groups are hydrogen atoms. Similarly, ^{it is preferable that one group of R 23 to} R ²⁵ is a monovalent organic group and the remaining two groups are hydrogen atoms.

Among them, ^{it is preferable that R 20} is a monovalent organic group and R ²¹ and R ²² are hydrogen atoms for the following reasons. According to the studies by the present inventors, it is considered preferable to reduce steric hindrance in the copolymer and maintain the flatness and the conjugated structure in order to obtain high conversion efficiency. Therefore, it is preferable that there are no adjacent structural units or substituents of the adjacent structural units in the extension direction ^{of R 1} and R ⁴ in the formula (I). Here, the extending direction of the R ^22, 5-membered ring adjacent to the naphthoquinone jumping steel thiadiazole units, or to the 5-membered ring has groups (R ¹ or R ⁴⁾ are present, R ²² is these and steric hindrance It is preferably a hydrogen atom that is difficult to generate. Further, in the 5-membered ring having ^{R 20 to} R ^{22 , R 20} is bonded to the 5-position of the ring, and R ²¹ is bonded to the 4-position of the ring. Here, since the ring has ^{an atom selected from the elements of Group 16 of the periodic table as represented by X 14} , the distance between the 2nd and 5th positions of the ring is the distance of the ring. It is longer than between the 2nd and 4th place. Therefore, if R ²⁰ is a monovalent organic group and R ²¹ is a hydrogen atom, steric hindrance with the 5-membered ring adjacent to the naphthothiadiazole unit can be further reduced.

For the same reason, it is preferable that ^{R 23} is a monovalent organic group and R ²⁴ and R ^{25 are hydrogen atoms.}

In this case, R ²⁰ and R ²³ are preferably branched aliphatic hydrocarbon groups for the following reasons. ^{Since the groups represented by R 1} and R ⁴ of the formula (I) have a limited number of carbon atoms and their shapes, there is a limit to improving the solubility of the copolymer. On the other hand, even if R ²⁰ and R ²³ are branched aliphatic hydrocarbon groups, the flatness of the copolymer is maintained because steric hindrance with other rings and substituents is unlikely to occur due to the above reason. At the same time, it is considered that the solubility can be improved.

Among them, when R ²⁰ and R ²³ are branched aliphatic hydrocarbon groups, the aliphatic hydrocarbon groups are used in order to improve the solubility and the interaction between the conjugated structure and the main chain. The number of carbon atoms is preferably 7 or more, more preferably 12 or more, more preferably 14 or more, while preferably 24 or less, further preferably 20 or less, and 18 The following is more preferable, and 16 is most preferable.

The copolymer according to the second aspect of the present invention may have a repeating unit other than the repeating unit represented by the formula (I) as long as the effect of the present invention is not impaired. The other repeating unit is not particularly limited, and examples thereof include the acceptor-type structural unit and the donor-type structural unit described above. The ratio of the number of repeating units represented by the formula (I) to the total number of repeating units constituting the copolymer according to the present invention is not particularly limited, but is usually 0.02 or more, preferably 0.1 or more, more preferably. Is 0.25 or more, more preferably 0.5 or more, still more preferably 0.7 or more, and the upper limit is 1.

The terminal portion of the copolymer according to the second aspect of the present invention is not particularly limited, but is preferably end-gap with an aromatic hydrocarbon ring, an aromatic heterocycle, or a hydrogen atom.

The polystyrene-equivalent weight average molecular weight (Mw) of the copolymer according to the first aspect of the present invention is not particularly limited, but may be 10,000 or more in order to obtain a long wavelength and high carrier mobility. It is preferably 30,000 or more, more preferably 40,000 or more, while it is preferably 300,000 or less, preferably 250,000 or less, in order to appropriately ensure solubility. It is more preferably present, and particularly preferably 245,000 or less. The weight average molecular weight is preferably in this range from the viewpoint of lengthening the light absorption wavelength, achieving high absorbance, achieving high carrier transfer, and solubility in an organic solvent.

The polystyrene-equivalent weight average molecular weight (Mw) of the copolymer according to the second aspect of the present invention is not particularly limited, but may be 10,000 or more in order to obtain a long wavelength and high carrier mobility. Preferably, it is more preferably 100,000 or more, particularly preferably 150,000 or more, while it is preferably 450,000 or less, preferably 400,000 or less, in order to appropriately ensure solubility. It is more preferably present, and particularly preferably 380,000 or less. The weight average molecular weight is preferably in this range from the viewpoint of lengthening the light absorption wavelength, achieving high absorbance, achieving high carrier transfer, and solubility in an organic solvent.

The polystyrene-equivalent number average molecular weight (Mn) of the copolymer according to one aspect of the present invention is not particularly limited, but is preferably 5,000 or more in order to obtain a long wavelength and high carrier mobility. It is more preferably 10,000 or more, particularly preferably 15,000 or more, and on the other hand, it is preferably 100,000 or less, and 80,000 or less in order to appropriately ensure solubility. Is more preferable, and 60,000 or less is particularly preferable.

The molecular weight distribution (PDI, (weight average molecular weight / number average molecular weight (Mw / Mn))) of the copolymer according to one aspect of the present invention is usually 1.0 or more, preferably 1.1 or more, and 1 It is more preferably 2 or more, and particularly preferably 1.3 or more. On the other hand, the molecular weight distribution of the copolymer according to the present invention is usually 50.0 or less, preferably 20.0 or less, more preferably 15.0 or less, and particularly preferably 10.0 or less. ..

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

The solubility of the copolymer according to one aspect of the present invention is not particularly limited, but the solubility in chlorobenzene at 25 ° C. is usually 0.1% by mass or more, preferably 0.5% by mass or more, and more preferably 1% by mass. 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.

It is preferable that the copolymer according to one aspect of the present invention causes an appropriate interaction between molecules. In the present specification, the interaction between molecules means that the distance between polymer chains is shortened due to the interaction such as π-π stacking between molecules. The stronger the interaction, the higher the mobility and / or the tendency to show crystallinity, and thus it is considered to be suitable as a semiconductor material. That is, since electron transfer between molecules is likely to occur in a copolymer that interacts between molecules, for example, when the copolymer according to the present invention is used in the active layer in a photoelectric conversion element, the p-type semiconductor compound in the active layer It is considered that the 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).

Examples of the method for measuring crystallinity include an X-ray diffraction method (XRD). In the present specification, having crystallinity means that the X-ray diffraction spectrum obtained by the XRD measurement has a diffraction peak. Having crystallinity is considered to mean having a laminated structure in which molecules are arranged, and is preferable in that the active layer described later tends to be thickened. The XRD measurement can be performed based on the method described in a known document (X-ray crystallography guide (Applied Physics Selection 4)).

The hole mobility (sometimes referred to as hole mobility) of the copolymer according to one aspect of 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 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 ^{It is 2} cm ² / Vs or less, and particularly preferably 1.0 × 10 cm ² / Vs or less. Since 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, the balance between the mobility of the n-type semiconductor compound and the mobility of the p-type semiconductor compound is important. When the copolymer according to the present invention is used as a p-type semiconductor compound in a photoelectric conversion element, the positive mobility of the copolymer according to the present invention is considered 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. It is preferable that the hole mobility is in this range. The FET method can be mentioned as a method for measuring the hole mobility. The FET method can be performed by the method described in a publicly known document (Japanese Patent Laid-Open No. 2010-545186).

The copolymer according to one aspect of the present invention preferably has high storage stability in a solution state. High storage stability means that it does not easily aggregate when made into a solution. More specifically, cooling is started when 2 mg of the copolymer according to the present invention is 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. It is preferable that the gel does not gel for 5 minutes or more, and more preferably 1 hour or more.

It is preferable that the amount of impurities in the copolymer according to one aspect of the present invention is as small as possible. In particular, when a transition metal catalyst such as palladium or copper is used when synthesizing a copolymer having a repeating unit represented by the formula (1), these may remain in the copolymer. If these metal catalysts remain in the copolymer, exciton traps are generated due to the heavy atomic effect of the transition metal, which hinders charge transfer. As a result, when the copolymer according to the present invention is used for a photoelectric conversion element, photoelectric is used. There is a risk of reducing conversion efficiency. Therefore, the concentration of the transition metal catalyst is usually 1000 ppm or less, preferably 500 pm or less, and more preferably 100 ppm or less per 1 g of the 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. The ICP mass spectrometry method can be carried out by the method described in a publicly known document (“Plasma Ion Source Mass Spectrometry” (Society Publishing Center)). Specifically, for palladium atoms and copper atoms, after wet decomposition of the sample, Pd and Sn in the decomposition liquid are subjected to calibration curve method using an ICP mass spectrometer (ICP mass spectrometer 7500ce type manufactured by Agilent Technologies). Can be quantified.

<2-1. Method for producing copolymer according to the first aspect of the present invention>
The method for producing the copolymer according to the first aspect of the present invention is not particularly limited, and for example, a compound represented by the following formula (XI), a compound represented by the following formula (XII), and the following formula ( It can be produced by a polymerization reaction between a compound represented by XIII) and a compound represented by the following formula (XIV).

X ^1, X ^2, R ¹ in the formula ^{(XI), R 2, R} 3 and R ^4, X ^1, X ² of the formula (I) described in the copolymers according to the first aspect, respectively, Synonymous with R ¹ , R ² , R ³ and R ^4. A in the above formula ^{(XII), Ar 3, Ar} 4, c and d are as defined ^{A, Ar 3, Ar 4,} c and d of the above formula (II). D1 in the above formula (XIII) is synonymous with D1 in the above formula (I). D2 in the above formula (XIV) is synonymous with D2 in the above formula (II). When D1 and D2 are the same structural unit, a copolymer is obtained by a polymerization reaction between the compound represented by the above formula (XI), the compound represented by the above formula (XII), and the compound represented by the above formula (XIII). Can be manufactured.

^{Y 1 to Y 8} in the formulas (XI) to (XIV) are active groups. The active group is not particularly limited and may be arbitrarily selected depending on the type of synthetic reaction. Specific active groups include, for example, a halogen atom, an alkylstanyl group, an alkylsulfo group, an arylsulfo group, an arylalkylsulfo group, a borate ester residue, a sulfonium methyl group, a phosphonium methyl group, a phosphonate methyl group, and a mono. Examples thereof include a methyl halide group, a boric acid residue (-B (OH) ₂ ), a formyl group, an alkenyl group, an alkynyl group and the like.

The polymerization reaction of the copolymer is not particularly limited as long as the copolymer of the present invention can be obtained. For example, Suzuki-Miyaura cross-coupling reaction method, Stille coupling reaction method, Yamamoto coupling reaction method, Grignard reaction method, Heck. Examples thereof include a reaction method, a garden reaction method, a reaction method _{using an oxidizing agent such as FeCl 3} , a method using an electrochemical oxidation reaction, and a reaction method by decomposing an intermediate compound having an appropriate leaving group. Among these, the Suzuki-Miyaura coupling reaction method, the Stille coupling reaction method, the Yamamoto coupling reaction method, and the Grignard reaction method are preferable because the structure can be easily controlled. In particular, the Suzuki-Miyaura cross-coupling reaction method, the Stille coupling reaction method, and the Grignard reaction method are preferable from the viewpoints of easy availability of materials and ease of reaction operation. These reactions are "Cross Coupling-Basics and Industrial Applications- (CMC Publishing)", "Transition Metal Catalyzed Reactions for Organic Synthesis (Jiro Tsuji: Edited by Society of Synthetic Organic Chemistry)", "For Organic Synthesis" It can be carried out according to the method described in publicly known documents such as "Catalytic Reaction 103 (Taejiro Hiyama: Tokyo Kagaku Dojin)".

More specifically, compounds represented by the above formulas (XI) to (XIV) are produced by a known Stille coupling reaction ^{, using Y 1 to Y 4} as an alkylstanyl group and Y ^{5 to Y 8 as halogen atoms.} A method for ^{producing Y 1 to Y 4} as a borate ester residue or a borate residue and Y ^{5 to Y 8} as a halogen atom by a known Suzuki-Miyaura coupling reaction, Y ^{1 to Y 4} as a silyl. As a group, a method of producing by a Hiyama coupling reaction using ^{Y 5 to Y 8 as halogen atoms can be mentioned.}

If necessary, a catalyst may be used in the polymerization reaction.

It is preferable to carry out end treatment of the copolymer obtained by the polymerization reaction. By performing the end treatment of the copolymer, ^{the residual amount of the terminal residues of the copolymer (Y 1 to Y 8} described above) can be reduced. By performing such end treatment, the amount of active groups such as halogen atoms and alkylstanyl groups can be reduced in the obtained copolymer, so that the conversion efficiency and durability of the photoelectric conversion element can be improved. Can be done.

The method for producing the compounds represented by the above formulas (XI) to (XIV) is not particularly limited and can be produced by a known method. For example, as a method for producing the compound represented by the above formula (XI), it can be produced by a known method of Japanese Patent Application Laid-Open No. 2014-009163. Further, as a method for producing the compounds represented by the above formulas (XI) to (XIV), for example, 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. Mol. Mater. Chem. , 2011, 21, 3895-3902, J. Mol. Am. Chem. Soc. , 2011, 133, 10021-10065 or Chem. Commun. , 2011, 47, 4920, WO2013 / 180243 and the like.

<2-2. Method for producing copolymer according to the second aspect of the present invention>
The method for producing a copolymer according to the second aspect of the present invention is not particularly limited, and is, for example, by a polymerization reaction between a compound represented by the following formula (XI) and a compound represented by the following formula (XIII). Can be manufactured.

X ¹ in the formula ^{(XI), X 2, R} 1, R 2, R 3 and R ⁴ respectively, X ¹ in formula (I) described in the copolymers according to the second aspect, X ^2, R It is synonymous with ¹ , R ² , R ³ and R ^4. D1 in the above formula (XIII) is synonymous with D1 in the above formula (I).

^{Y 1} and Y ^{2 in} formula (XI) and Y ^{5 and Y 6 in} formula (XIII) represent active groups, respectively. The active group is not particularly limited and may be arbitrarily selected depending on the type of synthetic reaction. Specific active groups include, for example, a halogen atom, an alkylstanyl group, an alkylsulfo group, an arylsulfo group, an arylalkylsulfo group, a borate ester residue, a sulfonium methyl group, a phosphonium methyl group, a phosphonate methyl group, and a mono. Examples thereof include a methyl halide group, a boric acid residue (-B (OH) ₂ ), a formyl group, an alkenyl group, an alkynyl group and the like.

The polymerization reaction of the copolymer is not particularly limited as long as the copolymer of the present invention can be obtained, and the method described in the method for producing a copolymer of the first aspect can be used.

More specifically, compounds represented by the above formulas (XI) and (XIII) are produced by a known Stille coupling reaction ^{, using Y 1} and Y ² as an alkylstanyl group and Y ⁵ and Y ^{6 as halogen atoms.} A method for ^{producing Y 1} and Y ² as borate ester residues or borate residues, and Y ⁵ and Y ⁶ as halogen atoms by a known Suzuki-Miyaura coupling reaction, and Y ¹ and Y ² being silyl. As a group, a method of producing by Hiyama coupling reaction using ^{Y 5} and Y ^{6 as halogen atoms can be mentioned.}

If necessary, a catalyst may be used in the polymerization reaction.

It is preferable to carry out end treatment of the copolymer obtained by the polymerization reaction. By performing the end treatment of the copolymer, ^{the residual amount of the terminal residues of the copolymer (Y 1 to Y 2} and Y ^{5 to Y 6} described above) can be reduced. By performing such end treatment, the amount of active groups such as halogen atoms and alkylstanyl groups can be reduced in the obtained copolymer, so that the conversion efficiency and durability of the photoelectric conversion element can be improved. Can be done.

The method for producing the compounds represented by the above formulas (XI) and (XIII) is not particularly limited, and can be produced by the known method described in the method for producing a copolymer of the first aspect.

<3. Photoelectric conversion element>
The copolymer according to the present invention can be used as a material for a photoelectric conversion element. Specifically, since the active layer of the photoelectric conversion element contains the copolymer according to the present invention, it has both high conversion efficiency and 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 the present invention has 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 the 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 is a lower electrode 101, a lower buffer layer 102, an active layer 103, an upper buffer layer 104, and an upper electrode on a base material 106. It has a layered structure in which 105 and 105 are sequentially formed. In the present invention, the lower electrode means an electrode laminated on the base material 106 side, and the upper electrode means an electrode laminated on the upper side of the lower base electrode when the base material 106 is 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. Further, the lower buffer layer 102 and the upper buffer layer 104 are not essential configurations and may be provided arbitrarily, and may have only one of the lower buffer layer 102 and the upper buffer layer 104. Further, 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. Base material 106>
The photoelectric conversion element 107 is usually formed on a base material 106 that serves as a support. There are no particular restrictions on the material of the base material 106. Preferable examples of the material of the base material 106 include an inorganic material such as quartz, glass, sapphire or titania, a flexible base material and the like. Specific examples of the flexible substrate include, but are not limited to, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, polyimide, nylon, polystyrene, polyvinyl alcohol, ethylene vinyl alcohol copolymer, fluororesin film, and vinyl chloride. Or a polyolefin such as polyethylene; an organic material (resin base material) such as cellulose, polyvinylidene chloride, aramid, polyphenylene sulfide, polyurethane, polycarbonate, polyarylate, polynorbornene or epoxy resin; a paper material such as paper or synthetic paper; stainless steel, Examples thereof include composite materials such as those obtained by coating or laminating the surface of a metal foil such as titanium or aluminum in order to impart insulating properties. Examples of the glass include soda glass, blue plate glass, non-alkali glass and the like. Of these, non-alkali glass is preferable because the amount of eluted ions from the glass is small.

There are no particular restrictions on the shape, composition, etc. of the base material 106, and well-known techniques can be referred to. For example, those described in International Publication No. 2011/016430 or Japanese Patent Application Laid-Open No. 2012-191194 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. Therefore, the pair of electrodes includes an electrode suitable for collecting holes (hereinafter, may be referred to as an anode) and an electrode suitable for collecting electrons (hereinafter, also referred to as a cathode). It is preferable to use it. It is preferable that one of the pair of electrodes has translucency, and both electrodes may have translucency. In addition, having translucency means that sunlight is transmitted by 40% or more. Further, the solar light transmittance of the transparent electrode is preferably 70% or more in order to allow the transparent electrode to pass through and allow light to reach the active layer. The light transmittance can be measured with a normal spectrophotometer.

The anode is an electrode having a function of collecting holes generated by the active layer 3 absorbing light, and the cathode has a function of collecting electrons generated in the active layer 3. It is an electrode. When the lower electrode 101 is used as an anode, the upper electrode 105 is preferably used as a cathode, and when the lower electrode 101 is used as a cathode, the upper electrode 105 may be used as an anode.

The material for forming the lower electrode 101 and the upper electrode 105 is not particularly limited, and nickel oxide, tin oxide, indium oxide, indium tin oxide (ITO), indium-zirconium oxide (IZO), titanium oxide, indium oxide or zinc oxide. Conductive metal oxides such as gold, platinum, silver, copper, iron, tin, zinc, aluminum, indium, chromium, lithium, sodium, potassium, cesium, calcium or magnesium or cobalt and other metals or alloys thereof. ..

Among the above materials, when the lower electrode 101 is used as an anode and the upper electrode 105 is used as a cathode, it is preferable to use a material having a work function larger than that of the upper electrode 105. On the other hand, when the lower electrode 101 is used as a cathode and the upper electrode 105 is used as an anode, the lower electrode 101 is preferably formed of a material having a work function smaller than that of the upper electrode 105. When the photoelectric conversion element has the lower buffer layer 102 and / or the upper buffer layer 104 as described later, the lower electrode 101 and the upper portion can be adjusted by adjusting the work function of the lower buffer layer 102 and / or the upper buffer layer 104. The electrode 105 can also be formed of a material having the same work function.

The lower electrode 101 and the upper electrode 105 may be single-layered or laminated, respectively.

When the base material 106 side is the light receiving surface, the lower electrode 101 preferably has translucency. On the other hand, when the upper electrode 105 side is used as the light receiving surface, the lower electrode 2 may have translucency or has translucency as long as the upper electrode 105 has translucency. You don't have to.

The film thicknesses of the lower electrode 101 and the upper electrode 105 are not particularly limited, but are preferably 10 nm or more, more preferably 20 nm or more, and particularly preferably 50 nm or more in order to suppress sheet resistance. On the other hand, it is preferably 10 μm or less, more preferably 1 μm or less, and particularly preferably 500 nm or less in order to ensure high translucency.

The method for forming the lower electrode 101 and the upper electrode 105 is not particularly limited, and may be formed by a known method according to the material to be used. For example, a vacuum film forming method such as a vapor deposition method or a sputtering method, or a wet coating method in which an ink containing nanoparticles or a precursor is applied to form a film can be mentioned. The electrical characteristics, wetting characteristics, and the like may be improved by performing surface treatment on the lower electrode 101 and the upper electrode 105.

<3-3. Active layer 103>
The active layer 103 contains a p-type semiconductor compound and an n-type semiconductor compound, and is a layer on which photoelectric conversion is performed. 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 taken out from the anode and the cathode. Is done.

The layer structure of the active layer 103 includes a thin film laminated type in which a layer containing a p-type semiconductor compound and a layer containing an n-type semiconductor compound are laminated, or a layer in which a p-type semiconductor compound and an n-type semiconductor compound are mixed. The bulk heterojunction type having is mentioned. The bulk heterojunction type 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 are further laminated in addition to the mixed layer. From the viewpoint that high photoelectric conversion efficiency can be expected, the bulk heterojunction type is preferable.

The active layer 103 preferably contains the copolymer according to the present invention as a p-type semiconductor compound. When the active layer 103 contains the copolymer according to the present invention, it is possible to provide a photoelectric conversion element having high conversion efficiency.

The active layer 103 may contain other p-type semiconductor compounds in addition to the copolymer according to the present invention. The other p-type semiconductor compound may be a low molecular weight organic compound or a high molecular weight compound. Although there are no particular restrictions on these p-type semiconductor compounds, those described in publicly known documents such as International Publication No. 2011/016430 or Japanese Patent Application Laid-Open No. 2012-191194 can be used.

The n-type semiconductor compound is not particularly limited, but for example, a fullerene; a fullerene derivative; a quinolinol derivative metal complex typified by 8-hydroxyquinolin aluminum; a fused ring such as naphthalenetetracarboxylic acid diimide or perylenetetracarboxylic acid diimide. Diimides of tetracarboxylic acid; perylene diimide derivative, terpyridine metal complex, tropolone metal complex, flavonol metal complex, perinone derivative, benzimidazole derivative, benzoxazole derivative, thiazole derivative, benzthiazole derivative, benzothiazol derivative, oxadiazole derivative, thiadiazol Derivatives, triazole derivatives, aldazine derivatives, bisstyryl derivatives, pyrazine derivatives, phenanthroline derivatives, quinoxalin derivatives, benzoquinoline derivatives, bipyridine derivatives, borane derivatives; total fluorides of condensed polycyclic aromatic hydrocarbons such as anthracene, pyrene, naphthacene or pentacene. Examples thereof include single-layer carbon nanotubes and n-type polymers (n-type polymer semiconductor materials).

Among these, fullerene compounds, borane derivatives, thiazole derivatives, benzothiazole derivatives, benzothiasiazol derivatives, N-alkyl substituted naphthalenetetracarboxylic acid diimides, N-alkyl substituted perylenediimide derivatives or n-type polymer semiconductor materials. Is preferable, a fullerene compound, an N-alkyl substituted perylenemidi derivative, an N-alkyl substituted naphthalene tetracarboxylic acid diimide or an n-type polymer semiconductor compound are more preferable, and a fullerene compound is particularly preferable. As these compounds, there are no particular restrictions, but for example, those described in publicly known documents such as International Publication No. 2011/016430 or Japanese Patent Application Laid-Open No. 2012-191194 can be used. One of the above compounds may be used, or 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 film thickness of the active layer 103 is not particularly limited, but is preferably 10 nm or more, more preferably 50 nm or more, and further preferably 100 nm or more in order to improve the uniformity of the film and suppress a short circuit. It is particularly preferable, on the other hand, it is preferably 1 μm or less, more preferably 500 nm or less, and particularly preferably 200 nm or less in order to reduce the internal resistance and improve the diffusion of electric charges.

The method for producing the active layer 103 is not particularly limited, but it is preferably formed by a coating method because it improves productivity. Specifically, it is preferable to apply the composition for forming an active layer containing the copolymer according to the present invention to form the active layer 103.

Any method can be used as the coating method, for example, spin coating method, reverse roll coating method, gravure coating method, kiss coating method, roll brushing method, spray coating method, air knife coating method, wire barber coating method, pipe. Doctor method, impregnation / coating method, curtain coating method and the like can be mentioned.

When forming a laminated active layer, at least an active layer forming ink containing the 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 by a coating method. The p-type semiconductor-containing layer and the n-type semiconductor-containing layer may be laminated to form an active layer. On the other hand, when forming a bulk heterotype active layer, a bulk heterotype active layer is formed by a coating method using at least a copolymer according to the present invention as a p-type semiconductor compound and an active layer forming composition containing an n-type semiconductor compound. It suffices to form an active layer of.

The above-mentioned composition for forming an active layer usually contains a solvent in addition to the above-mentioned compounds. The solvent is not particularly limited, but for example, aliphatic hydrocarbons such as hexane, heptane, octane, isooctane, nonane, tetraline or decane; Aromatic hydrocarbons; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclohexane, cycloheptane, cyclooctane, tetraline or decalin; lower alcohols such as methanol, ethanol or propanol; acetone, methyl ethyl ketone, cyclopentanone Alternatively, aliphatic ketones such as cyclohexanone; aromatic ketones such as acetophenone or propiophenone; esters such as ethyl acetate, butyl acetate or methyl lactate; halogen hydrocarbons such as chloroform, methylene chloride, dichloroethane, trichloroethane or trichloroethylene. ; Ethers such as ethyl ether, tetrahydrofuran or dioxane; or amides such as dimethylformamide or dimethylacetamide can be mentioned.

As the solvent, one kind of solvent may be used alone, or any two or more kinds of solvents may be used in combination at any 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-boiling and high-boiling solvents include non-halogen aromatic hydrocarbons and alicyclic hydrocarbons, non-halogen aromatic hydrocarbons and aromatic ketones, ethers and alicyclic hydrocarbons. Examples thereof include hydrogens, ethers and aromatic ketones, aliphatic ketones and alicyclic hydrocarbons, or aliphatic ketones and aromatic ketones. Specific examples of preferable combinations include toluene and tetraline, xylene and tetraline, toluene and acetophenone, xylene and acetophenone, tetrahydrofuran and tetraline, tetrahydrofuran and acetophenone, methyl ethyl ketone and tetraline, methyl ethyl ketone and acetophenone, and the like.

In addition to the above-mentioned compounds, the composition for forming an active layer may contain other additives and the like as long as the effects according to the present invention are not impaired.

<3-4. Lower buffer layer 102 and upper buffer layer 104>
The photoelectric conversion element according to the embodiment of the present invention has a lower buffer layer 102 between the lower electrode 101 and the active layer 103, and an 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. The 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 the 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 do not have to have the lower buffer layer 102 and the upper buffer layer 104, which are not essential components of the photoelectric conversion element according to the present invention. Further, it may have only one of the layers.

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 preferably a hole extraction layer. On the other hand, when the lower electrode 101 is an anode and the upper electrode 105 is a cathode, it is preferable that the lower buffer layer 102 is a hole extraction layer and the upper buffer layer 104 is an electron extraction layer.

<3-4-1. Electronic 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 electron extraction from the active layer 103 to the cathode, and examples thereof include an inorganic compound and an organic compound.

Examples of the inorganic compound include salts of alkali metals such as Li, Na, K or Cs; _{n-type semiconductor oxides such as titanium oxide (TiO x} ) 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 operating mechanism of such a material is unknown, it is conceivable to reduce the work function of the cathode when combined with a cathode composed of Al or the like and increase the voltage applied to the inside of 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 a triarylphosphine oxide compound; substituents such as vasocuproin (BCP) or vasofenantrene (Bphenyl). A phenanthrene compound in which the 1-position and the 10-position may be replaced with a hetero atom; a boron compound such as triarylboron; an organic _{substance such as (8-hydroxyquinolinato) aluminum (Alq 3).} Metal oxides; compounds having one or two ring structures that may have substituents, such as oxadiazole compounds or benzoimidazole compounds; naphthalenetetracarboxylic acid anhydrides (NTCDA) or perylenetetracarboxylic acid anhydrides. Examples thereof include aromatic compounds having a condensed dicarboxylic acid structure such as a dicarboxylic acid anhydride such as a substance (PTCDA).

The film thickness of the electron extraction layer is usually 0.1 nm or more, preferably 1 nm or more, and more preferably 10 nm or more. On the other hand, it is usually 400 nm or less, preferably 200 nm or less. When the film thickness of the electron extraction layer is 0.1 nm or more, it functions as a buffer material, and when the film thickness of the electron extraction layer is 400 nm or less, electrons can be easily extracted and the photoelectric conversion efficiency is improved. Can be improved.

The LUMO energy level of the material of the electron extraction layer is not particularly limited, but is usually -4.0 eV or more, preferably -3.9 eV or more. On the other hand, it is usually -1.9 eV or less, preferably -2.0 eV or less. It is preferable that the LUMO energy level of the material of the electron extraction layer is -1.9 eV or less in that charge transfer can be promoted. It is preferable that the LUMO energy level of the material of the electron extraction layer is -4.0 eV or more because the back electron transfer to the n-type semiconductor material can be prevented.

The HOMO energy level of the material of the electron extraction layer is not particularly limited, but is usually −9.0 eV or higher, preferably −8.0 eV or higher. On the other hand, it is usually −5.0 eV or less, preferably −5.5 eV or less. It is preferable that the HOMO energy level of the material of the electron extraction layer is -5.0 eV or less in that holes can be prevented from moving.

Examples of the method for calculating the LUMO energy level and the HOMO energy level of the material of the electron extraction layer include a cyclic voltammogram measurement method. For example, it can be carried out with reference to the method described in a publicly known document (International Publication No. 2011/016430).

When the material of the electron extraction layer is an organic compound, the glass transition temperature of this compound (hereinafter, may be referred to as Tg) as measured by the DSC method is not particularly limited, but is not observed or is observed. It is preferably 55 ° C. or higher. If the glass transition temperature is not observed by the DSC method, it means that there is no glass transition temperature. Specifically, it is determined by the presence or absence of a glass transition temperature of 400 ° C. or lower. A material in which the glass transition temperature is not observed by the DSC method is preferable because it has high thermal stability.

Further, among the compounds having a glass transition temperature of 55 ° C. or higher as measured by the DSC method, the glass transition temperature is preferably 65 ° C. or higher, more preferably 80 ° C. or higher, still more preferably 110 ° C. or higher, particularly preferably 110 ° C. or higher. A compound having a temperature of 120 ° C. or higher is desirable. On the other hand, the upper limit of the glass transition temperature is not particularly limited, but is usually 400 ° C. or lower, preferably 350 ° C. or lower, and more preferably 300 ° C. or lower. Further, it is preferable that the material of the electron extraction layer is one in which the glass transition temperature by the DSC method is not observed at 30 ° C. or higher and lower than 55 ° C.

The glass transition temperature in the present specification is defined as a temperature at which local molecular motion is started by thermal energy in an amorphous solid, and is defined as a point at which the specific heat changes. When the temperature rises further than Tg, the solid structure changes and crystallization occurs (the temperature at this time is defined as the crystallization temperature (Tc)). When the temperature rises further, it generally melts at the melting point (Tm) and changes to a liquid state. However, these phase transitions may not be observed due to molecular decomposition or sublimation at high temperatures.

The DSC method is a method for measuring thermophysical properties (differential scanning calorimetry) defined in JIS K-0129 “General rules for thermal analysis”. In order to determine the glass transition temperature more clearly, it is desirable to measure after rapidly cooling the sample once heated to a temperature above the glass transition point. For example, the measurement can be carried out by the method described in the publicly known document (International Publication No. 2011/016430).

When the glass transition temperature of the compound used for the electron extraction layer is 55 ° C. or higher, the structure of this compound is unlikely to change due to external stress such as applied electric field, flowing current, stress due to bending or temperature change. , Preferred in terms of durability. Furthermore, since the crystallization of the thin film of the compound tends to be difficult to proceed, the compound is difficult to change between the amorphous state and the crystalline state in the operating temperature range, so that the stability as an electron extraction layer is good. Therefore, it is preferable in terms of durability. This effect becomes more pronounced as the glass transition temperature of the material increases.

There is no limitation on the method of forming the electron extraction layer. For example, when a sublimable material is used, it can be formed by a vacuum vapor deposition method or the like. Further, for example, when a material soluble in a solvent is used, it can be formed by a wet coating method such as spin coating or inkjet.

When the electron extraction layer is formed by the coating method, the coating liquid may further contain a surfactant. The use of the surfactant suppresses the occurrence of dents and / or uneven coating in the drying process due to the adhesion of minute bubbles or foreign substances. As the surfactant, known surfactants (cationic surfactants, anionic surfactants, nonionic surfactants) can be used. Of these, silicon-based surfactants, acetylenediol-based surfactants, and fluorine-based surfactants are preferable. As the surfactant, only one type may be used, or two or more types may be used in any combination and ratio.
Specifically, for example, when an alkali metal salt is used as a material for the electron extraction layer, the electron extraction layer can be formed by using a vacuum deposition method such as vacuum deposition or sputtering. Above all, it is desirable to form an electron extraction layer by vacuum deposition by resistance heating. By using vacuum deposition, damage to other layers such as the active layer can be reduced.

On the other hand, with respect to the metal oxide of the n-type semiconductor, for example, when zinc oxide ZnO is used as the material of the electron extraction layer, a vacuum film forming method such as a sputtering method can be used, but electrons are used by using a coating method. It is desirable to form a take-out layer. For example, Sol-Gel Science, C.I. J. Brinker, G.M. W. An electron extraction layer composed of zinc oxide can be formed according to the sol-gel method described in Academic Press (1990) by Scherer. In this case, the film thickness is usually 0.1 nm or more, preferably 2 nm or more, more preferably 5 nm or more, and usually 1 μm or less, preferably 100 nm or less, more preferably 50 nm or less. If the electron extraction layer is too thin, the effect of improving the electron extraction efficiency is not sufficient, and if it is too thick, the electron extraction layer acts as a series resistance component, which tends to impair the characteristics of the device.

<3-4-2. Hole extraction layer>
The material of the hole extraction layer is not particularly limited, and is not particularly limited as long as it is a material capable of improving the efficiency of extraction of holes from the active layer 103 to the anode. Specifically, a conductive polymer obtained by doping polythiophene, polypyrrole, polyacetylene, triphenylenediamine, polyaniline, etc. with sulfonic acid and / or iodine, a polythiophene derivative having a sulfonyl group as a substituent, a conductive organic substance such as arylamine, etc. Examples thereof include compounds, metal oxides such as copper oxide, nickel oxide, manganese oxide, molybdenum oxide, vanadium oxide or tungsten oxide, nafion, and p-type semiconductors described later. Among them, a conductive polymer doped with sulfonic acid is preferable, and a polythiophene derivative is preferably doped with polystyrene sulfonic acid (3,4-ethylenedioxythiophene) poly (styrene sulfonic acid) (PEDOT: PSS). Is. Further, a thin film of a metal such as gold, indium, silver or palladium can also be used. A thin film such as a metal may be formed alone or in combination with the above-mentioned organic material.

The film thickness of the hole extraction layer is usually 0.1 nm or more. On the other hand, it is usually 400 nm or less, preferably 200 nm or less. When the film thickness of the hole extraction layer is 0.1 nm or more, it functions as a buffer material, and when the film thickness of the hole extraction layer is 400 nm or less, holes can be easily extracted and photoelectric. Conversion efficiency can be improved.

There is no limitation on the method of forming the hole extraction layer. For example, when a material having sublimation property is used, it can be formed by a vacuum vapor deposition method or the like. Further, for example, when a material soluble in a solvent is used, it can be formed by a wet coating method such as a spin coating method or an inkjet method. When a semiconductor material is used for the hole extraction layer, the precursor may be converted into a semiconductor compound after forming a layer using the precursor, as in the case of the low molecular weight organic semiconductor compound in the active layer.
Among them, when PEDOT: PSS is used as the material of the hole extraction layer, it is preferable to form the hole extraction layer by a method of applying a dispersion liquid. Examples of the PEDOT: PSS dispersion liquid include the CLEVIOSTM series manufactured by Heraeus and the ORGACONTM series manufactured by Agfa.

When the hole extraction layer is formed by the coating method, the coating liquid may further contain a surfactant. The use of the surfactant suppresses the occurrence of dents and / or uneven coating in the drying process due to the adhesion of minute bubbles or foreign substances. As the surfactant, known surfactants (cationic surfactants, anionic surfactants, nonionic surfactants) can be used. Of these, silicon-based surfactants, acetylenediol-based surfactants, and fluorine-based surfactants are preferable. As the surfactant, only one type may be used, or two or more types may be used in any combination and ratio.

Although the example of the photoelectric conversion element according to the embodiment of the present invention has been described above, the structure of the photoelectric conversion element according to the present invention is not limited to the above structure. For example, the photoelectric conversion element may have a tandem type structure having two or more active layers 103.

<3-5. Manufacturing method of photoelectric conversion element>
The photoelectric conversion element 107 having the configuration shown in FIG. 1 has a lower electrode 101, a lower buffer layer 102, an active layer 103, an upper buffer layer 104, and an upper electrode on the base material 106 according to the above-mentioned method described for each layer. It can be produced by sequentially laminating 105.

After laminating the lower electrode 101 and / or the upper electrode 105, annealing treatment may be performed by heating. The adhesion of each layer can be improved by performing the annealing treatment. When the annealing treatment is performed, the heating temperature is not particularly limited, but in order to improve the adhesion of each layer, it is preferably 50 ° C. or higher, more preferably 80 ° C. or higher, while the photoelectric conversion element. In order to suppress thermal decomposition of the material constituting the above, the temperature is preferably 300 ° C. or lower, and particularly preferably 250 ° C. or lower.

The heating time is not particularly limited, but is preferably 1 minute or more, more preferably 3 minutes or more, and more preferably 3 hours or less, further preferably 1 hour or less. .. Further, the annealing treatment is preferably carried out under normal pressure and in an atmosphere of an inert gas.

The heating may be performed by placing the photoelectric conversion element on a heat source such as a hot plate, or by placing the photoelectric conversion element in a heating atmosphere such as an oven. Further, the heating may be performed by a batch method or a continuous method.

Each layer constituting the photoelectric conversion element according to the present invention is not particularly limited and may be formed by a sheet-to-sheet (single-wafer) method or a roll-to-roll method.

The roll-to-roll method is a method in which a flexible base material wound in a roll shape is unwound and processed intermittently or continuously while being wound by a take-up roll. is there. According to the roll-to-roll method, since it is possible to collectively process long substrates on the order of km, it is a production method more suitable for mass production than the sheet-to-sheet method.

<3-6. Photoelectric conversion characteristics>
The photoelectric conversion characteristics of the photoelectric conversion element 107 can be obtained as follows. Irradiate the photoelectric conversion element 107 with light under AM1.5G condition with a solar simulator. Intensity 100 mW / cm2
Irradiate with and measure the current-voltage characteristics. 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, and more preferably 2% or more. On the other hand, there is no particular upper limit, and the higher the limit, the better.

Further, as a method of measuring the durability of the photoelectric conversion element, there is a method of determining the maintenance rate of the photoelectric conversion efficiency before and after exposing the photoelectric conversion element to the atmosphere.
(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 being simple and inexpensive to manufacture. From this viewpoint, the maintenance rate of the photoelectric conversion efficiency before and after exposure to the atmosphere for one week is preferably 60% or more, more preferably 80% or more, and the higher the better.

<4. Solar cells ＞
The photoelectric conversion element according to the above-described embodiment is preferably used as a solar cell element of a solar cell, particularly a thin-film solar cell. FIG. 2 is a cross-sectional view schematically showing the configuration of a thin-film solar cell as an embodiment of the present invention. As shown in FIG. 2, the thin film solar cell 14 of the present embodiment includes a weather resistant protective film 1, an ultraviolet cut film 2, a gas barrier film 3, a getter film 4, a sealing material 5, and a photoelectric conversion element. 6, the sealing material 7, the getter material film 8, the gas barrier film 9, and the back sheet 10 are provided in this order. Then, in the thin film solar cell, light is usually irradiated from the side where the weather resistant protective film 1 is formed (lower part in the figure), and the photoelectric conversion element 6 generates electricity. The thin-film solar cell does not have 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 publicly known documents such as International Publication No. 2011/016430 or Japanese Patent Application Laid-Open No. 2012-191194 can be used.

The application of the solar cell according to the present invention, particularly the thin-film solar cell 14 described above, is not particularly limited and can be used in any application. Examples thereof include solar cells for building materials, solar cells for automobiles, solar cells for spacecraft, 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 may be used as a solar cell module by installing the solar cell on a substrate, for example. For example, as shown in FIG. 3, as a solar cell module 13 having a thin-film solar cell 14 on a base material 12, it can be installed and used at a place of use. As the base material 12, a well-known technique can be used, and for example, those described in International Publication No. 2011/016430 or Japanese Patent Application Laid-Open No. 2012-191194 can be used. For example, when a plate material for building materials is used as the base material 12, a solar cell panel can be manufactured as a solar cell module 13 by providing a thin-film solar cell 14 on the surface of the plate material.

Hereinafter, embodiments of the present invention will be described with reference to examples, but the present invention is not limited thereto as long as the gist of the present invention is not exceeded.
The items described in this example were measured by the following methods.

[Measurement method of 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: Polymer Laboratories GPC column (PLgel MIXED-B 10 μm, inner diameter 7.5 mm, length 30 cm) Used by connecting two in series Pump: LC-10AT (manufactured by Shimadzu Corporation)
Oven: CTO-10A (manufactured by Shimadzu Corporation)
Detectors: Differential Refractometer Detector (Shimadzu Corporation, RID-10A), UV-vis Detector (Shimadzu Corporation, RID-10A) and UV-vis Detector (Shimadzu Corporation, SPD-10A)
Sample: 1 μL of a solution prepared by dissolving 1 mg of a sample in orthodichlorobenzene (200 mg).
Mobile phase: orthodichlorobenzene
Flow velocity: 1.0 mL / min
Temperature: 80 ° C
Analysis: LC-Solution (manufactured by Shimadzu Corporation)

<Synthesis Example 1A: Synthesis of Copolymer 1A>

3,7-Di (2-bromo-3-dodecylthiophene-5-5) obtained as a monomer in a 50 mL two-port eggplant flask under a nitrogen atmosphere by referring to the method described in US Patent Application Publication No. 2012/0227812. Il) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A1) (29.8 mg, 0.033 mmol), with reference to Japanese Patent Application Laid-Open No. 2014-501032. 4,7-Bis- (5-bromo-thiophen-2-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound A2) (16.3 mg, 0.033 mmol) , And 4,8-bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6-bis (trimethyl) obtained with reference to the method described in Japanese Patent Application Laid-Open No. 2014-501032. Stanyl) -benzo [1,2-b: 4,5-b'] dithiophene (Compound D1) (74.5 mg, 0.066 mmol) was added, and tris (dibenzylideneacetone) dipalladium chloroform complex (2. 7 mg, 4.0 mol%), tris (2-methylphenyl) phosphine (6.4 mg, 32 mol%) and chlorobenzene (5.0 mL) were added, and the mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 1 hour. As a terminal treatment, trimethyl (phenyl) tin (0.03 mL) and chlorobenzene (5.0 mL) were added to the reaction solution, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, and then bromobenzene (1.0 mL) was further added. The reaction solution was poured into methanol by heating and stirring at 110 ° C. for 1.0 hour, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 1A was obtained in a yield of 74%. The weight average molecular weight Mw of the obtained copolymer 1A was 187,000, and the PDI was 4.5.

<Synthesis Example 2A: Synthesis of Copolymer 2A>

3,7-di (2-bromo-3-dodecylthiophene-5-5) obtained as a monomer in a 50 mL two-necked eggplant flask under a nitrogen atmosphere by referring to the method described in US Patent Application Publication No. 2012/0227812. Il) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A1) (59.6 mg, 0.066 mmol), and JP-A-2014-501032. 4,8-Bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6-bis (trimethylstanyl) -benzo [1,2-b] obtained with reference to the above method. : 4,5-b'] Dithiophene (Compound D1) (74.5 mg, 0.066 mmol) was added, and tetrakis (triphenylphosphine) palladium (0) (2.3 mg, 3.00 mol%) and triphenylphosphine were added. Non-uniform palladium complex catalyst Pd-EnCatTPP30 (manufactured by Aldrich, 3.0 mg, 1.53 mol%), toluene (4.0 mL), and N, N-dimethylformamide (1.0 mL) were added and at 100 ° C. The mixture was stirred for 1 hour and then at 110 ° C. for 2 hours. The reaction mixture is diluted 2-fold with toluene and heated and stirred at 110 ° C. for an additional 0.5 hours, then trimethyl (phenyl) tin (0.03 mL) is added as a terminal treatment, and the reaction mixture is heated and stirred at 110 ° C. for 1.0 hour. Then, bromobenzene (1.00 mL) was further added, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, the reaction solution was poured into methanol, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 2A was obtained in a yield of 87%. The weight average molecular weight Mw of the obtained copolymer 2A was 52,000, and the PDI was 2.2.

<Synthesis Example 3A: Synthesis of Copolymer 3A>

In a nitrogen atmosphere, in a 50 mL two-necked eggplant flask, 4,7-bis- (5-bromo-thiophen-2-yl) -5, 6- obtained as a monomer with reference to Japanese Patent Publication No. 2014-501032 Difluoro-benzo [1,2,5] thiadiazole (Compound A2) (32.6 mg, 0.066 mmol), and 4,8-bis- obtained by referring to the method described in JP-A-2014-501032. [5- (2-Hexyldecyl) -thiophen-2-yl] -2,6-bis (trimethylstanyl) -benzo [1,2-b: 4,5-b'] dithiophene (Compound D1) (74 Add .5 mg, 0.066 mmol), and further add tris (dibenzylideneacetone) dipalladium chloroform complex (2.73 mg, 4.00 mol%), tris (2-methylphenyl) phosphine (3.21 mg, 16.00 mol%). , Chlorobenzene (5.0 mL) was added, and the mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 2 hours. The reaction mixture is diluted 2-fold with chlorobenzene and stirred at 110 ° C. for an additional 0.5 hour, then trimethyl (phenyl) tin (0.03 mL) is added as a terminal treatment, and the mixture is heated and stirred at 110 ° C. for 1.0 hour. Then, bromobenzene (1.00 mL) was further added, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, the reaction solution was poured into methanol, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 3A was obtained in a yield of 56%. The weight average molecular weight Mw of the obtained copolymer 3A was 199,000, and the PDI was 4.1.

<Synthesis Example 4A: Synthesis of Copolymer 4A>

A 3,7-di (2-bromo-3-dodecylthiophene-5-5) obtained as a monomer in a 50 mL twin-necked eggplant flask under a nitrogen atmosphere by referring to the method described in US Patent Application Publication No. 2012/0227812. Il) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A1) (29.8 mg, 0.033 mmol), published literature (Chem. Mater., 2008, 20,4045-4050), 4,7-bis- (5-bromo-thiophen-2-yl) -benzo [1,2,5] thiadiazole (Compound A3) (15.1 mg, 0) .033 mmol) and 4,8-bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6- obtained by referring to the method described in JP-A-2014-501032. Bis (trimethylstanyl) -benzo [1,2-b: 4,5-b'] dithiophene (Compound D1) (74.5 mg, 0.066 mmol) was added, and tetrakis (triphenylphosphine) palladium (0) was added. (2.3 mg, 3.00 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 3.0 mg, 1.53 mol%), toluene (4.0 mL), and N, N -Dimethylformamide (1.0 mL) was added and stirred at 100 ° C. for 1 hour, followed by 110 ° C. for 2 hours. The reaction mixture is diluted 2-fold with toluene and heated and stirred at 110 ° C. for an additional 0.5 hours, then trimethyl (phenyl) tin (0.03 mL) is added as a terminal treatment, and the reaction mixture is heated and stirred at 110 ° C. for 1.0 hour. Then, bromobenzene (1.00 mL) was further added, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, the reaction solution was poured into methanol, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 4A was obtained in a yield of 84%. The weight average molecular weight Mw of the obtained copolymer 4A was 54,000, and the PDI was 2.4.

<Synthesis Example 5A: Synthesis of Copolymer 5A>

3,7-Di (2-bromo-3-dodecylthiophene-5-5) obtained as a monomer in a 50 mL two-necked eggplant flask under a nitrogen atmosphere by referring to the method described in US Patent Application Publication No. 2012/0227812. Il) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A1) (17.9 mg, 0.020 mmol), with reference to Japanese Patent Application Laid-Open No. 2014-501032. 4,7-Bis- (5-bromo-thiophen-2-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound A2) (22.8 mg, 0.046 mmol) , And 4,8-bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6-bis (trimethyl) obtained with reference to the method described in JP-A-2014-50132. Stanyl) -benzo [1,2-b: 4,5-b'] dithiophene (Compound D1) (74.5 mg, 0.066 mmol) was added, and tetrakis (triphenylphosphine) palladium (0) (2. 3 mg, 3.00 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 3.0 mg, 1.53 mol%), toluene (4.0 mL), and N, N-dimethylformamide. (1.0 mL) was added, and the mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 2 hours. The reaction mixture is diluted 2-fold with toluene and heated and stirred at 110 ° C. for an additional 0.5 hours, then trimethyl (phenyl) tin (0.03 mL) is added as a terminal treatment, and the reaction mixture is heated and stirred at 110 ° C. for 1.0 hour. Then, bromobenzene (1.00 mL) was further added, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, the reaction solution was poured into methanol, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 5A was obtained in a yield of 56%. The weight average molecular weight Mw of the obtained copolymer 5A was 67,000, and the PDI was 3.0.

<Synthesis Example 6A: Synthesis of Copolymer 6A>

A 3,7-di (2-bromo-3-dodecylthiophene-5-5) obtained as a monomer in a 50 mL twin-necked eggplant flask under a nitrogen atmosphere by referring to the method described in US Patent Application Publication No. 2012/0227812. Il) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A1) (29.8 mg, 0.033 mmol), with reference to Japanese Patent Application Laid-Open No. 2014-501032. 4,7-Bis- (5-bromo-thiophen-2-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound A2) (16.3 mg, 0.033 mmol) , 4,8-Bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6-Bis (trimethylsta) obtained with reference to the method described in JP-A-2014-501032. Nyl) -benzo [1,2-b: 4,5-b'] dithiophene (Compound D1) (37.3 mg, 0.033 mmol) is added and known literature (ACS Macro Lett., 2013, 2,605-). 4,8-Bis- [5- (2-butyloctyl) -thiophen-2-yl] -2,6-bis (trimethylstanyl) -benzo [1] obtained with reference to the method described in 608). , 2-b: 4,5-b'] Dithiophene (Compound D2) (33.6 mg, 0.033 mmol) was added, and tetrakis (triphenylphosphine) palladium (0) (2.3 mg, 3.00 mol%), Triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (manufactured by Aldrich, 3.0 mg, 1.53 mol%), toluene (4.0 mL), and N, N-dimethylformamide (1.0 mL) were added. The mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 2 hours. The reaction mixture is diluted 2-fold with toluene and heated and stirred at 110 ° C. for an additional 0.5 hours, then trimethyl (phenyl) tin (0.03 mL) is added as a terminal treatment, and the reaction mixture is heated and stirred at 110 ° C. for 1.0 hour. Then, bromobenzene (1.00 mL) was further added, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, the reaction solution was poured into methanol, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 6A was obtained in a yield of 86%. The weight average molecular weight Mw of the obtained copolymer 6A was 47,000 and the PDI was 2.5.

<Synthesis Example 7A: Synthesis of Copolymer 7A>

3,7-Di (2-bromo-3-dodecylthiophene-5-5) obtained as a monomer in a 50 mL two-necked eggplant flask under a nitrogen atmosphere by referring to the method described in US Patent Application Publication No. 2012/0227812. Il) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A1) (29.8 mg, 0.033 mmol), with reference to Japanese Patent Application Laid-Open No. 2014-501032. 4,7-Bis- (5-bromo-thiophen-2-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound A2) (16.3 mg, 0.033 mmol) , And 4,8-bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6-bis (trimethyl) obtained with reference to the method described in JP-A-2014-50132. Stanyl) -benzo [1,2-b: 4,5-b'] dithiophene (Compound D1) (74.5 mg, 0.066 mmol) was added, and tetrakis (triphenylphosphine) palladium (2.3 mg, 3) was added. .0 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (purchased from Aldrich, 3.0 mg, 3 mol%), toluene (4.0 mL), and N, N-dimethylformamide (1.0 mL) ) Was added, and the mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 1 hour. As a terminal treatment, trimethyl (phenyl) tin (0.03 mL) and chlorobenzene (5.0 mL) were added to the reaction solution, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, and then bromobenzene (1.0 mL) was further added. The reaction solution was poured into methanol by heating and stirring at 110 ° C. for 1.0 hour, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 7A was obtained in 79% yield. The weight average molecular weight Mw of the obtained copolymer 7A was 72,000, and the PDI was 2.7.

<Synthesis Example 8A: Synthesis of Copolymer 8A>
[Synthesis example: Synthesis of 4-tetradecyl-2-trimethylstanylthiophene (Compound T2)]

2,2,6,6-tetramethylpiperidin (2.18 g, 15 mmol) was added to a 50 mL two-necked flask, and nitrogen substitution was performed three times. 10 mL of dry THF was added, and the mixture was cooled to −78 ° C. in a dry ice acetone bath. n-Butyllithium (1.6M, 8.9 mL, 14.3 mmol) was added dropwise at −78 ° C., the mixture was stirred for 30 minutes, and then the temperature was raised to 0 ° C. in an ice bath. On the other hand, 3-tetradecylthiophene (Compound T1) (4.3 g, 15 mmol) was added to a 500 mL four-necked flask, and nitrogen substitution was carried out three times. 190 mL of dry THF was added, and the mixture was cooled to −40 ° C. in a dry ice acetone bath. The previously prepared LiTMP was slowly added dropwise at −40 ° C., and after the completion of the addition, the mixture was stirred for another 1 hour, trimethyltin chloride (1 Min THF 15 mL, 15 mmol) was added dropwise, and the mixture was stirred for 30 minutes. 100 mL of distilled water was added to quench the reaction, and the aqueous layer was extracted once with hexane. The organic layer was washed 3 times with water and dried over anhydrous sodium sulfate. The solvent was distilled off with an evaporator and dried under reduced pressure (oil pump) at 40 ° C. to obtain 4-tetradecyl-2-trimethylstanylthiophene (Compound T2). As a result of proton NMR, the purity of the tin body was 70%.

[Synthesis example: Synthesis of 3,7-di (3-tetradecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound T4) ]

4-Tetradecyl-2-trimethylstanylthiophene (Compound T2) (2.37 g (P.70%) 3.75 mmol), 3,7-dibromo-naphtho [1,2-c: 5,] in a 50 mL two-necked flask. 6-c] Bis [1,2,5] thiadiazole (Compound T3) (603 mg, 1.5 mmol) was added, and nitrogen substitution was performed three times. Tetrakistriphenylphosphine palladium (34.9 mg, 0.02 mmol) was added and nitrogen substitution was performed twice. 70 mL of dehydrated toluene and 7 mL of dehydrated DMF were added, and the mixture was stirred at 115 ° C. for 3 hours. Toluene was distilled off after cooling to room temperature. 20 mL of ethyl acetate was added, the mixture was stirred, and the mixture was filtered off. The separated solid was sprinkled with ethyl acetate three times, washed and dried. The obtained orange solid was dissolved by heating in 300 mL of chloroform and purified by a short-pass silica gel column. By distilling off the solvent and drying under reduced pressure, 3,7-di (3-tetradecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5 ] Thiadiazole (Compound T4) was obtained in 1.13 g with a yield of 94%.

[Synthetic example: 3,7-di (2-bromo-3-tetradecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (compound) Synthesis of A4)]

3,7-Di (3-tetradecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound T4) (1) in a 2L eggplant flask .13 g, 1.42 mmol) was added, 1000 mL of chloroform was added, and the mixture was heated and stirred using a dryer. After cooling to room temperature and shading the flask with aluminum foil, a chloroform solution of bromine (493 mg, 3.09 mmol) was quickly added dropwise at room temperature. After stirring at room temperature for 1 hour, 90% of the solvent was distilled off. The obtained red slurry liquid was filtered under reduced pressure and sprinkled with chloroform three times for washing. By drying at 50 ° C. under reduced pressure, 3,7-di (2-bromo-3-tetradecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2, 5] Thiadiazole (Compound A4) was obtained in 1.34 g with a yield of 98%.

[Synthesis example: Synthesis of copolymer 8A]

In a nitrogen atmosphere, in a 50 mL two-necked eggplant flask, as a monomer, 3,7-di (2-bromo-3-tetradecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A4) (31.6 mg, 0.033 mmol), 4,7-bis- (4,7-bis-) obtained with reference to JP-A-2014-501032. 5-Bromo-thiophen-2-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound A2) (16.3 mg, 0.033 mmol), and JP-A-2014-501032. 4,8-Bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6-bis (trimethylstanyl) -benzo [1,2-b] obtained with reference to the above method. : 4,5-b'] Dithiophene (Compound D1) (74.5 mg, 0.066 mmol) was added, and tris (dibenzylideneacetone) dipalladium chloroform complex (2.7 mg, 4.0 mol%) and tris (2) were added. -Methylphenyl) phosphene (3.2 mg, 16 mol%) and chlorobenzene (5.0 mL) were added, and the mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 1 hour. As a terminal treatment, trimethyl (phenyl) tin (0.03 mL) and chlorobenzene (5.0 mL) were added to the reaction solution, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, and then bromobenzene (1.0 mL) was further added. The reaction solution was poured into methanol by heating and stirring at 110 ° C. for 1.0 hour, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 8A was obtained in a yield of 77%. The weight average molecular weight Mw of the obtained copolymer 8A was 162,000, and the PDI was 4.2.

<Synthesis Example 9A: Synthesis of Copolymer 9A>
[Synthesis example: Synthesis of 4-decyl-2-trimethylstanylthiophene (Compound T6)]

2,2,6,6-tetramethylpiperidin (3.15 g, 22.3 mmol) was added to a 100 mL two-necked flask, and nitrogen substitution was performed three times. 15 mL of dry THF was added, and the mixture was cooled to −78 ° C. in a dry ice acetone bath. n-Butyllithium (1.54M, 13.7 mL, 21.1 mmol) was added dropwise at −78 ° C., the mixture was stirred for 30 minutes, and then the temperature was raised to 0 ° C. in an ice bath. On the other hand, 3-decylthiophene (Compound T5) (5 g, 22.3 mmol) was added to a 500 mL four-necked flask, and nitrogen substitution was carried out three times. 250 mL of dry THF was added and cooled to −30 ° C. in a dry ice acetone bath. The previously prepared LiTMP was slowly added dropwise at −30 ° C., and after completion of the addition, the mixture was further stirred for 45 minutes, then a THF solution of trimethyltin chloride (4.45 g, 22.3 mmol) was added dropwise, and the mixture was stirred for 45 minutes. 100 mL of distilled water was added to quench the reaction, and the aqueous layer was extracted once with hexane. The organic layer was washed 3 times with water and dried over anhydrous sodium sulfate. The solvent was distilled off with an evaporator and dried under reduced pressure (oil pump) at 40 ° C. to obtain 4-decyl-2-trimethylstanylthiophene (Compound T6). As a result of proton NMR, the purity of the tin body was 86.9%.

[Synthesis example: Synthesis of 3,7-di (3-decylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (compound T7)]

4-decyl-2-trimethylstanylthiophene (Compound T6) (1.14 g (P.86.9%) 2.5 mmol), 3,7-dibromo-naphtho [1,2-c:] in a 100 mL two-necked flask. 5,6-c] bis [1,2,5] thiadiazole (Compound T3) (403 mg, 1 mmol) was added, and nitrogen substitution was performed three times. Tetrakistriphenylphosphine palladium (23.1 mg, 0.02 mmol) was added and nitrogen substitution was performed twice. 45 mL of dehydrated toluene and 4.5 mL of dehydrated DMF were added, and the mixture was stirred at 115 ° C. for 3 hours. After cooling to room temperature, 20 mL of ethyl acetate was added, the mixture was stirred, and the mixture was filtered off. The separated solid was sprinkled with ethyl acetate three times, washed and dried. The obtained orange solid was dissolved by heating in 200 mL of chloroform and purified by a short-pass silica gel column. By distilling off the solvent and drying under reduced pressure, 3,7-di (3-decylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] Thiadiazole (Compound T7) was obtained. It was used as it was in the next process.

[Synthetic example: 3,7-di (2-bromo-3-decylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A5) ) Synthesis]

Put 3,7-di (3-decylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound T7) in a 1 L eggplant flask. 500 mL of chloroform was added, and the mixture was heated and stirred using a dryer. After cooling to room temperature and shading the flask with aluminum foil, a chloroform solution of bromine (450 mg, 2.8 mmol) was quickly added dropwise at room temperature. After stirring at room temperature for 1 hour, 90% of the solvent was distilled off. The obtained red slurry liquid was filtered under reduced pressure and sprinkled with chloroform three times for washing. By drying at 50 ° C. under reduced pressure, 3,7-di (2-bromo-3-decylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5 ] Thiadiazole (Compound A5) was obtained in 717 mg, yield 84% (two steps).

[Synthesis example: Synthesis of copolymer 9A]

In a nitrogen atmosphere, in a 50 mL two-port eggplant flask, as a monomer, 3,7-di (2-bromo-3-decylthiophene-5-yl) -naphtho [1,2-c: 5] obtained by the above method. , 6-c] bis [1,2,5] thiadiazole (Compound A5) (27.4 mg, 0.032 mmol), 4,7-bis- (5) obtained with reference to Japanese Patent Application Laid-Open No. 2014-501032. -Bromo-thiophen-2-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound A2) (16.0 mg, 0.032 mmol), and JP-A-2014-501032. 4,8-Bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6-bis (trimethylstanyl) -benzo [1,2-b: obtained by referring to the method: 4,5-b'] Dithiophene (Compound D1) (74.5 mg, 0.066 mmol) was added, and tris (dibenzylideneacetone) dipalladium chloroform complex (2.7 mg, 4.0 mol%) and tris (2-). Methylphenyl) phosphene (3.2 mg, 16 mol%) and chlorobenzene (5.0 mL) were added, and the mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 1 hour. As a terminal treatment, trimethyl (phenyl) tin (0.03 mL) and chlorobenzene (5.0 mL) were added to the reaction solution, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, and then bromobenzene (1.0 mL) was further added. The reaction solution was poured into methanol by heating and stirring at 110 ° C. for 1.0 hour, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 9A was obtained in a yield of 77%. The weight average molecular weight Mw of the obtained copolymer 9A was 162,000, and the PDI was 5.9.

<Synthesis Example 10A: Synthesis of Copolymer 10A>
[Synthesis example: Synthesis of 3-pentadecylthiophene (Compound T9)]

[1,3-Bis (diphenylphosphino) propane] dichloronickel (542 mg, 1 mmol) was added to a 500 mL four-necked flask, and nitrogen substitution was performed three times. 100 mL of dry diethyl ether was added, and a THF solution of pentadecylmagnesium bromide (0.4 M, 5 mL, 2 mmol) was slowly added dropwise at room temperature. Then 3-bromothiophene (Compound T8) (16.3 g, 100 mmol) was added. A THF solution of pentadecylmagnesium bromide (0.4M, 245 mL, 98 mmol) was added dropwise, and the mixture was further stirred for 2 hours. The reaction was quenched by adding 20 mL of 1N hydrochloric acid, and the aqueous layer was extracted once with hexane. The organic layer was washed once with water and once with saturated aqueous sodium chloride solution and dried over anhydrous sodium sulfate. The solvent was distilled off with an evaporator, and the origin component was removed by a short-pass silica gel column. The alkyl residue was removed under reduced pressure (oil pump) at 100 ° C. to obtain 26.7 g of 3-pentadecylthiophene (Compound T9) in a yield of 90%.

[Synthesis example: Synthesis of 4-pentadecylic-2-trimethylstanylthiophene (Compound T10)]

TMPMgCl.LiCl (1.0 M THF solution, 12 mL, 12 mmol) was added to a nitrogen-substituted 50 mL two-necked flask, and 3-pentadecylthiophene (Compound T9) (2.95 g, 10 mmol) and 5 mL of dry THF were added. After stirring for 2 hours, the mixture was cooled in an ice bath, and a dry THF solution of trimethyltin chloride (2.4 g, 12 mmol) was slowly added dropwise. The temperature was raised to room temperature, the mixture was stirred for 1 hour, and then quenched with water. The aqueous layer was extracted once with hexane, the organic layer was washed 3 times with water and dried over anhydrous sodium sulfate. The solvent was distilled off with an evaporator and dried under reduced pressure (oil pump) at 50 ° C. 4-Pentadecylic-2-trimethylstanylthiophene (Compound T10) was obtained by purification with recycled preparative GPC. As a result of proton NMR, the purity of the tin body was 90%.

[Synthesis example: Synthesis of 3,7-di (3-pentadecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound T11) ]

4-Pentadecyl-2-trimethylstanylthiophene (Compound T10) (656 mg (P.90%), 1.29 mmol), 3,7-dibromo-naphtho [1,2-c: 5,6] in a 100 mL two-necked flask. -C] Bis [1,2,5] thiadiazole (Compound T3) (200 mg, 0.497 mmol) was added, and nitrogen substitution was performed three times. Tetrakistriphenylphosphine palladium (11.5 mg, 0.01 mmol) was added and nitrogen substitution was performed twice. 20 mL of dehydrated toluene and 2 mL of dehydrated DMF were added, and the mixture was stirred at 115 ° C. for 3 hours. After cooling to room temperature, 10 mL of ethyl acetate was added, the mixture was stirred, and the mixture was filtered off. The separated solid was sprinkled with ethyl acetate three times, washed and dried. The obtained orange solid was dissolved by heating in 200 mL of chloroform and purified by a short-pass silica gel column. By distilling off the solvent and drying under reduced pressure, 3,7-di (3-pentadecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5 ] Thiadiazole (Compound T11) was obtained in 410 mg with a yield of 99%.

[Synthetic example: 3,7-di (2-bromo-3-pentadecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (compound) Synthesis of A6)]

3,7-di (3-pentadecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound T11) (410 mg) in a 1 L eggplant flask , 0.497 mmol) was added, 400 mL of chloroform was added, and the mixture was heated and stirred using a dryer. After cooling to room temperature and shading the flask with aluminum foil, a chloroform solution of bromine (238 mg, 1.49 mmol) was quickly added dropwise at room temperature. After stirring at room temperature for 1 hour, 90% of the solvent was distilled off. The obtained red slurry liquid was filtered under reduced pressure and sprinkled with chloroform three times for washing. By drying at 50 ° C. under reduced pressure, 3,7-di (2-bromo-3-pentadecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2, 5] Thiadiazole (Compound A6) was obtained in 485 mg in a yield of 99%.

[Synthesis example: Synthesis of copolymer 10A]

In a nitrogen atmosphere, in a 50 mL two-necked eggplant flask, as a monomer, 3,7-di (2-bromo-3-pentadecylthiophene-5-yl) -naphtho [1,2-c: obtained by the above method. 5,6-c] bis [1,2,5] thiadiazole (Compound A6) (32.6 mg, 0.033 mmol), 4,7-bis- (4,7-bis-) obtained with reference to Japanese Patent Application Laid-Open No. 2014-501032. 5-Bromo-thiophen-2-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound A2) (16.3 mg, 0.033 mmol), and JP-A-2014-501032. 4,8-Bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6-bis (trimethylstanyl) -benzo [1,2-b] obtained with reference to the above method. : 4,5-b'] Dithiophene (Compound D1) (74.5 mg, 0.066 mmol) was added, and tris (dibenzylideneacetone) dipalladium chloroform complex (2.7 mg, 4.0 mol%) and tris (2) were added. -Methylphenyl) phosphene (3.2 mg, 16 mol%) and chlorobenzene (5.0 mL) were added, and the mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 1 hour. As a terminal treatment, trimethyl (phenyl) tin (0.03 mL) and chlorobenzene (5.0 mL) were added to the reaction solution, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, and then bromobenzene (1.0 mL) was further added. The reaction solution was poured into methanol by heating and stirring at 110 ° C. for 1.0 hour, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 10A was obtained in a yield of 75%. The weight average molecular weight Mw of the obtained copolymer 10A was 244,000, and the PDI was 4.8.

<Synthesis Example 11A: Synthesis of Copolymer 11A>
[Synthesis example: Synthesis of 4-octadecyl-2-trimethylstanylthiophene (Compound T13)]

TMPMgCl · LiCl (1.0 M THF solution, 12 mL, 12 mmol) was added to a nitrogen-substituted 50 mL two-necked flask, and a dry THF (5 mL) solution of 3-octadecylthiophene (Compound T12) (3.35 g, 10 mmol) was added at room temperature. added. After stirring for 2 hours, the mixture was cooled in an ice bath, and a dry THF solution of trimethyltin chloride (2.4 g, 12 mmol) was slowly added dropwise. The temperature was raised to room temperature, the mixture was stirred for 1 hour, and then quenched with water. The aqueous layer was extracted once with hexane, the organic layer was washed 3 times with water and dried over anhydrous sodium sulfate. The solvent was distilled off with an evaporator and dried under reduced pressure (oil pump) at 50 ° C. 4-Octadecyl-2-trimethylstanylthiophene (Compound T13) was obtained by purification with recycled preparative GPC. As a result of proton NMR, the purity of the tin body was 68%.

[Synthesis example: Synthesis of 3,7-di (3-octadecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound T14)]

4-Octadecyl-2-trimethylstanylthiophene (Compound T13) (988 mg (P.68%), 1.32 mmol), 3,7-dibromo-naphtho [1,2-c: 5,6] in a 100 mL two-necked flask. -C] Bis [1,2,5] thiadiazole (Compound T3) (200 mg, 0.497 mmol) was added, and nitrogen substitution was performed three times. Tetrakistriphenylphosphine palladium (11.5 mg, 0.01 mmol) was added and nitrogen substitution was performed twice. 20 mL of dehydrated toluene and 2 mL of dehydrated DMF were added, and the mixture was stirred at 115 ° C. for 3 hours. After cooling to room temperature, 10 mL of ethyl acetate was added, the mixture was stirred, and the mixture was filtered off. The separated solid was sprinkled with ethyl acetate three times, washed and dried. The obtained orange solid was dissolved by heating in 200 mL of chloroform and purified by a short-pass silica gel column. By distilling off the solvent and drying under reduced pressure, 3,7-di (3-octadecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] Thiadiazole (Compound T14) was obtained in 440 mg, yield 97%.

[Synthetic example: 3,7-di (2-bromo-3-octadecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A7) ) Synthesis]

3,7-di (3-octadecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound T14) (444 mg,) in a 1 L eggplant flask. 0.486 mmol) was added, 500 mL of chloroform was added, and the mixture was heated and stirred using a dryer. After cooling to room temperature and shading the flask with aluminum foil, a chloroform solution of bromine (408 mg, 2.55 mmol) was quickly added dropwise at room temperature. After stirring at room temperature for 1 hour, 90% of the solvent was distilled off. The obtained red slurry liquid was filtered under reduced pressure and sprinkled with chloroform three times for washing. By drying at 50 ° C. under reduced pressure, 3,7-di (2-bromo-3-octadecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5 ] Thiadiazole (Compound A7) was obtained in 494 mg, yield 95%.

[Synthesis example: Synthesis of copolymer 11A]

In a nitrogen atmosphere, in a 50 mL two-necked eggplant flask, as a monomer, 3,7-di (2-bromo-3-octadecylthiophene-5-yl) -naphtho [1,2-c: 5] obtained by the above method. , 6-c] bis [1,2,5] thiadiazole (Compound A7) (35.4 mg, 0.033 mmol), 4,7-bis- (5) obtained with reference to Japanese Patent Application Laid-Open No. 2014-501032. -Bromo-thiophen-2-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound A2) (16.3 mg, 0.033 mmol), and JP-A-2014-501032. 4,8-Bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6-bis (trimethylstanyl) -benzo [1,2-b: obtained by referring to the method: 4,5-b'] Dithiophene (Compound D1) (74.5 mg, 0.066 mmol) was added, and tris (dibenzylideneacetone) dipalladium chloroform complex (2.7 mg, 4.0 mol%) and tris (2-). Methylphenyl) phosphene (3.2 mg, 16 mol%) and chlorobenzene (5.0 mL) were added, and the mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 1 hour. As a terminal treatment, trimethyl (phenyl) tin (0.03 mL) and chlorobenzene (5.0 mL) were added to the reaction solution, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, and then bromobenzene (1.0 mL) was further added. The reaction solution was poured into methanol by heating and stirring at 110 ° C. for 1.0 hour, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 11A was obtained in a yield of 75%. The weight average molecular weight Mw of the obtained copolymer 11A was 149,000, and the PDI was 4.4.

<Synthesis Example 12A: Synthesis of Copolymer 12A>
[Synthesis example: Synthesis of 3,4-didodecylthiophene (Compound T16)]

In a 500 mL two-necked eggplant flask, add 3,4-dibromothiophene (Compound T15) (5.09 g, 20.7 mmol) and [1,3-bis (diphenylphosphino) propane] dichloronickel (224 mg, 0.41 mmol). In addition, nitrogen substitution was performed 3 times. 200 mL of dry diethyl ether was added and the mixture was cooled to 0 ° C. A THF solution of dodecylmagnesium bromide (1.0 M, 45.5 mL, 45.5 mmol) was slowly added, and after completion of the dropwise addition, the temperature was raised until reflux was achieved, and the mixture was stirred for 10 hours. The mixture was cooled to 0 ° C. again, hydrochloric acid water was added, and quenching was performed. The aqueous layer was extracted once with hexane and the organic layer was washed twice with water. After drying over anhydrous sodium sulfate, the solvent was distilled off. The origin component was removed by short-pass silica gel column chromatography using hexane as the developing solution. After distilling off the solvent, the low boiling point component was removed under reduced pressure to obtain 8.5 g of 3,4-didodecylthiophene (Compound T16) in a yield of 97%.

[Synthesis example: Synthesis of 3,4-didodecyl-2-trimethylstanylthiophene (Compound T17)]

3,4-Didodecylthiophene (Compound T16) (4.2 g, 9.98 mmol) was added to a 100 mL two-necked eggplant flask, and nitrogen substitution was carried out three times. 20 mL of dry THF was added and cooled in an ice bath. N-Butyllithium (1.6 M, 6.3 mL, 10 mmol) was added dropwise at 0 ° C., and the mixture was stirred for 1 hour and 30 minutes, and then a dry THF solution of trimethyltin chloride (2 g, 10 mmol) was slowly added dropwise. Water was added and quenched, the aqueous layer was extracted once with hexane, and the organic layer was washed 3 times with water. After drying over anhydrous sodium sulfate, the solvent was distilled off. By drying under reduced pressure (oil pump) at 40 ° C., 5.5 g of 3,4-didodecyl-2-trimethylstanylthiophene (Compound T17) was obtained in a yield of 94%.

[Synthetic example: 3,7-di (3,4-didodecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound T18) Synthesis]

3,4-Didodecyl-2-trimethylstanylthiophene (Compound T17) (1.46 g, 2.5 mmol), 3,7-dibromo-naphtho [1,2-c: 5,6] in a 100 mL two-necked eggplant flask. -C] Bis [1,2,5] thiadiazole (Compound T3) (403 mg, 1.0 mmol), dichlorobis [di-t-butyl (p-dimethylaminophenyl) phosphino] palladium (14.4 mg, 0.02 mmol) Was added and nitrogen substitution was performed 3 times. 16 mL of dry toluene and 4 mL of dry DMF were added, and the mixture was stirred at 100 ° C. for 8 hours. The mixture was cooled to room temperature, and methanol was added to cool the mixture. The precipitated solid was filtered and dried under reduced pressure. The origin component was removed by short-pass silica gel column chromatography using chloroform as the developing solution. Purified by recycled preparative GPC using chloroform as the developing solvent, 3,7-di (3,4-didodecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [ 1,2,5] Thiadiazole (Compound T18) was obtained at 568 mg in a yield of 52%.

[Synthetic example: 3,7-di (2-bromo-3,4-didodecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole Synthesis of (Compound A8)]

3,7-di (3,4-didodecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c'] bis [1,2,5] thiadiazole (Compound T18) (568 mg, (0.525 mmol) was added with 14 mL of ortodichlorobenzene and heated to 90 ° C. N-Bromosuccinimide (186 mg, 1.04 mmol) and 1.0 mL of acetic acid were added, and the mixture was stirred for 1 hour. The mixture was cooled to room temperature, methanol was added, and ultrasonic cleaning was performed. The precipitated solid was separated by filtration and dried under reduced pressure at 50 ° C. to 3,7-di (2-bromo-3,4-didodecylthiophene-5-yl) -naphtho [1,2-c: 5, 6-c] bis [1,2,5] thiadiazole (Compound A8) was obtained at 613 mg in a yield of 94%.

[Synthesis example: Synthesis of copolymer 12A]

In a nitrogen atmosphere, in a 50 mL two-port eggplant flask, as a monomer, 3,7-di (2-bromo-3,4-didodecylthiophene-5-yl) -naphtho [1,2-yl] obtained by the above method. c: 5,6-c] bis [1,2,5] thiadiazole (Compound A8) (39.3 mg, 0.032 mmol), 4,7-bis obtained with reference to Japanese Patent Application Laid-Open No. 2014-501032. -(5-Bromo-thiophen-2-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound A2) (15.7 mg, 0.032 mmol), and JP-A-2014-501032. 4,8-Bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6-bis (trimethylstanyl) -benzo [1,2] obtained with reference to the method described in 1. −B: 4,5-b'] Dithiophene (Compound D1) (74.5 mg, 0.066 mmol) was added, and tris (dibenzylideneacetone) dipalladium chloroform complex (2.7 mg, 4.0 mol%) and tris were added. (2-Methylphenyl) phosphene (3.2 mg, 16 mol%) and chlorobenzene (5.0 mL) were added, and the mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 1 hour. As a terminal treatment, trimethyl (phenyl) tin (0.03 mL) and chlorobenzene (5.0 mL) were added to the reaction solution, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, and then bromobenzene (1.0 mL) was further added. The reaction solution was poured into methanol by heating and stirring at 110 ° C. for 1.0 hour, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 12A was obtained in a yield of 73%. The weight average molecular weight Mw of the obtained copolymer 12A was 66,000, and the PDI was 2.2.

<Synthesis Example 13A: Synthesis of Copolymer 13A>
[Synthesis example: Synthesis of 3-dodecyl-2-bromothiophene (Compound T20)]

To a 200 mL two-necked eggplant flask, 3-dodecylthiophene (Compound T19) (10.5 g, 39.8 mmol), 50 mL of chloroform and 50 mL of acetic acid were added. After cooling in an ice bath and shading the flask with aluminum foil, NBS (6.38 g, 35.8 mmol) was added little by little. After confirming that the raw material had disappeared by TLC, ice was added and quenching was performed. The aqueous layer was extracted once with hexane. The organic layer was washed 3 times with water and 3 times with saturated brine, and dried over anhydrous sodium sulfate. The solvent was evaporated by evaporation and the crude product was purified by silica gel column chromatography to obtain 12.7 g of 3-dodecyl-2-bromothiophene (Compound T20) in a yield of 96%.

[Synthesis example: Synthesis of 3-dodecyl-2-trimethylstanylthiophene (Compound T21)]

3-Bromo-2-dodecylthiophene (Compound T20) (12.6 g, 38 mmol) was added to a 300 mL two-necked eggplant flask, and nitrogen substitution was carried out three times. 115 mL of dry THF was added and the mixture was cooled to 0 ° C. Isopropylmagnesium chloride lithium chloride complex (1.18M, 35mL, 41.3 mmol) was added. The temperature was raised to room temperature, and the mixture was stirred for 1 hour. The mixture was cooled to 0 ° C. again, trimethyltin chloride (1.0 M in THF 42 mL, 42 mmol) was added, and the mixture was stirred for 1 hour. Water was added and quenched, and the aqueous layer was extracted 3 times with hexane. The organic layer was washed 3 times with water and 1 time with saturated brine. The mixture was dried over anhydrous sodium sulfate and the solvent was distilled off to obtain 16.2 g of 3-dodecyl-2-trimethylstanylthiophene (Compound T21). As a result of proton NMR, the purity of the tin body was 80%.

[Synthesis example: Synthesis of 3,7-di (3-dodecylthiophen-2-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (compound T22)]

3-Dodecyl-2-trimethylstanylthiophene (Compound T21) (969 mg, 1.87 mmol), 3,7-dibromo-naphtho [1,2-c: 5,6-c] bis in a 100 mL twin-necked eggplant flask. [1,2,5] Thiadiazole (Compound T3) (300 mg, 0.746 mmol) and dichlorobis [di-t-butyl (p-dimethylaminophenyl) phosphino] palladium (10.6 mg, 0.015 mmol) were added and nitrogen substitution was performed. Was performed 3 times. 24 mL of dry toluene and 6 mL of dry DMF were added, and the mixture was stirred at 100 ° C. for 6 hours. It was cooled to room temperature, methanol was added and ultrasonic waves were applied. It was filtered and dried under reduced pressure. The origin component was removed by short-pass silica gel column chromatography using chloroform as the developing solvent, and reprecipitated with ethyl acetate to cause 3,7-di (3-dodecylthiophen-2-yl) -naphtho [1,2]. -C: 5,6-c] bis [1,2,5] thiadiazole (Compound T22) was obtained at 532 mg in a yield of 82%.

[Synthetic example: 3,7-di (2-bromo-4-dodecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A9) ) Synthesis]

3,7-Di (3-dodecylthiophen-2-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound T22) (74.5 mg, 0. 5 mL of ortodichlorobenzene was added to 1 mmol) and heated to 90 ° C. N-Bromosuccinimide (41.6 mg, 0.23 mmol) and 0.5 mL of acetic acid were added, and the mixture was stirred for 4 hours. The mixture was cooled to room temperature, methanol was added, and the mixture was filtered. By drying the obtained solid at 50 ° C. under reduced pressure, 3,7-di (2-bromo-4-dodecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [ 1,2,5] Thiadiazole (Compound A9) was obtained in 73.6 mg in a yield of 81%.

[Synthesis example: Synthesis of copolymer 13A]

In a nitrogen atmosphere, in a 50 mL two-necked eggplant flask, as a monomer, 3,7-di (2-bromo-4-dodecylthiophene-5-yl) -naphtho [1,2-c: 5] obtained by the above method. , 6-c] bis [1,2,5] thiadiazole (Compound A9) (28.6 mg, 0.032 mmol), 4,7-bis- (5) obtained with reference to Japanese Patent Application Laid-Open No. 2014-501032. -Bromo-thiophen-2-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound A2) (15.7 mg, 0.032 mmol), and JP-A-2014-501032. 4,8-Bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6-bis (trimethylstanyl) -benzo [1,2-b: obtained by referring to the method: 4,5-b'] Dithiophene (Compound D1) (74.5 mg, 0.066 mmol) was added, and tris (dibenzylideneacetone) dipalladium chloroform complex (2.7 mg, 4.0 mol%) and tris (2-). Methylphenyl) phosphene (3.2 mg, 16 mol%) and chlorobenzene (5.0 mL) were added, and the mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 1 hour. As a terminal treatment, trimethyl (phenyl) tin (0.03 mL) and chlorobenzene (5.0 mL) were added to the reaction solution, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, and then bromobenzene (1.0 mL) was further added. The reaction solution was poured into methanol by heating and stirring at 110 ° C. for 1.0 hour, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 13A was obtained in a yield of 51%. The weight average molecular weight Mw of the obtained copolymer 13A was 124,000, and the PDI was 4.5.

<Synthesis Example 14A: Synthesis of Copolymer 14A>
[Synthesis example: Synthesis of 5-trimethylsilyl-2-trimethylstanylthiophene (Compound T24)]

2-Trimethylsilylthiophene (Compound T23) (1.57 g, 10 mmol) was added to a 100 mL two-necked flask, and nitrogen substitution was carried out three times. 30 mL of dry THF was added, and the mixture was cooled to −78 ° C. in a dry ice acetone bath. LDA (1.13M, 7.9 mL, 9 mmol) was added dropwise at −78 ° C., and the mixture was stirred for 1 hour, trimethyltin chloride (1.79 g, 9 mmol) was added, and the mixture was stirred for 1 hour. Distilled water was added to quench the reaction, and the aqueous layer was extracted once with hexane. The organic layer was washed 3 times with water and dried over anhydrous sodium sulfate. The solvent was distilled off with an evaporator and dried under reduced pressure (oil pump) to obtain 2.3 g of 5-trimethylsilyl-2-trimethylstanylthiophene (Compound T24). As a result of proton NMR, the purity of the tin body was 90%.

[Synthesis example: Synthesis of 3,7-di (5-trimethylsilylthiophen-2-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound T25)]

5-trimethylsilyl-2-trimethylstanylthiophene (Compound T24) (886 mg (P.90%) 2.5 mmol), 3,7-dibromo-naphtho [1,2-c: 5,6--] in a 100 mL two-necked flask c] Bis [1,2,5] thiadiazole (Compound T3) (402 mg, 1.0 mmol) was added, and nitrogen substitution was performed three times. Tetrakistriphenylphosphine palladium (23.1 mg, 0.02 mmol) was added and nitrogen substitution was performed twice. 50 mL of dehydrated toluene and 5 mL of dehydrated DMF were added, and the mixture was stirred at 115 ° C. for 7 hours. Toluene was distilled off after cooling to room temperature. Methanol was added, the mixture was stirred, and the mixture was filtered off. The obtained orange solid was dissolved by heating in 250 mL of chloroform and purified by short-pass silica gel column chromatography. By distilling off the solvent and drying under reduced pressure, 3,7-di (5-trimethylsilylthiophen-2-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] Thiadiazole (Compound T25) was obtained in 528 mg, yield 95%.

[Synthesis example: Synthesis of 3,7-di (2-bromothiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A10)]

In a 2L eggplant flask, 3,7-di (5-trimethylsilylthiophen-2-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound T25) (528 mg, 0.95 mmol) was added, 1000 mL of chloroform was added, and the mixture was heated and stirred using a dryer. After cooling to room temperature and shading the flask with aluminum foil, a chloroform solution of bromine (323 mg, 2.02 mmol) was quickly added dropwise at room temperature. After stirring at room temperature for 1 hour, 90% of the solvent was distilled off. The obtained red slurry liquid was filtered under reduced pressure and sprinkled with chloroform three times for washing. By drying at 50 ° C. under reduced pressure, 3,7-di (2-bromothiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (compound) A10) was obtained in 540 mg with a yield of 100%.

[Synthesis example: Synthesis of copolymer 14A]

In a nitrogen atmosphere, in a 50 mL two-port eggplant flask, as a monomer, 3,7-di (2-bromo-thiophene-5-yl) -naphtho [1,2-c: 5,6-yl] obtained by the above method. c] Bis [1,2,5] thiadiazole (Compound A10) (17.6 mg, 0.031 mmol), 4,7-bis- (5-bromo-) obtained with reference to Japanese Patent Application Laid-Open No. 2014-501032. Thiophene-2-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound A2) (15.3 mg, 0.031 mmol), and the method described in JP-A-2014-501032. 4,8-Bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6-bis (trimethylstanyl) -benzo [1,2-b: 4,5 -B'] Dithiophene (Compound D1) (74.5 mg, 0.066 mmol) was added, and tris (dibenzylideneacetone) dipalladium chloroform complex (2.7 mg, 4.0 mol%) and tris (2-methylphenyl) were added. Phosphene (3.2 mg, 16 mol%) and chlorobenzene (5.0 mL) were added, and the mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 1 hour. As a terminal treatment, trimethyl (phenyl) tin (0.03 mL) and chlorobenzene (5.0 mL) were added to the reaction solution, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, and then bromobenzene (1.0 mL) was further added. The reaction solution was poured into methanol by heating and stirring at 110 ° C. for 1.0 hour, and the precipitated precipitate was collected by filtration. The obtained solid was insoluble in solvents such as chloroform, toluene and orthodichlorobenzene.

<Synthesis Example 15A: Synthesis of Copolymer 15A>

In a nitrogen atmosphere, in a 50 mL two-port eggplant flask, as a monomer, 3,7-di (2-bromo-3-dodecylthiophene-5-5) obtained by referring to the method described in US Patent Application Publication No. 2012/0227812 was obtained. Il) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A1) (29.8 mg, 0.033 mmol), known literature (Materials Chemistry, 2011, 21, 11, 4,7-Bis- (5-bromo-thiophen-2-yl)-[1,2,5] thiadiazole [3,4-c] pyridine (Compound A11) obtained with reference to 13247-13255) ( 15.2 mg, 0.033 mmol), and 4,8-bis- [5- (2-hexyldecyl) -thiophen-2-yl] obtained with reference to the methods described in JP-A-2014-501032. -2,6-bis (trimethylstanyl) -benzo [1,2-b: 4,5-b'] dithiophene (Compound D1) (74.5 mg, 0.066 mmol) was added, and tris (dibenzylideneacetone) was added. ) Dipalladium chloroform complex (2.7 mg, 4.0 mol%), tris (2-methylphenyl) phosphine (3.2 mg, 16 mol%), and chlorobenzene (5.0 mL) were added, followed by 1 hour at 100 ° C. The mixture was stirred at 110 ° C. for 1 hour. As a terminal treatment, trimethyl (phenyl) tin (0.03 mL) and chlorobenzene (5.0 mL) were added to the reaction solution, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, and then bromobenzene (1.0 mL) was further added. The reaction solution was poured into methanol by heating and stirring at 110 ° C. for 1.0 hour, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 15A was obtained in 80% yield. The weight average molecular weight Mw of the obtained copolymer 15A was 120,000 and the PDI was 4.4.

<Synthesis Example 16A: Synthesis of Copolymer 16A>

3,7-Di (2-bromo-3-tetradecylthiophene-5-5) obtained as a monomer in a 50 mL two-port eggplant flask under a nitrogen atmosphere by referring to the method described in US Patent Application Publication No. 2012/0227812. -Il) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A4) (44.5 mg, 0.046 mmol), Non-Patent Known Documents (Chem. Mater. 4,5'-dibromo-3,3'-difluoro-2,2'-bithiophene (Compound A12) (7.2 mg, 0.020 mmol) obtained by the method described in 2014, 26, 4214-4220), and a special table. 4,8-Bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6-bis (trimethylstanyl)-obtained by referring to the method described in 2014-50132 Add benzo [1,2-b: 4,5-b'] dithiophene (Compound D1) (76.3 mg, 0.068 mmol) and tris (dibenzylideneacetone) dipalladium chloroform complex (2.8 mg, 4.). 0 mol%), tris (2-methylphenyl) phosphine (6.6 mg, 32 mol%) and chlorobenzene (5.0 mL) were added, and the mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 1 hour. As a terminal treatment, trimethyl (phenyl) tin (0.03 mL) and chlorobenzene (2.5 mL) were added to the reaction solution, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, and then bromobenzene (1.0 mL) was further added. The reaction solution was poured into methanol by heating and stirring at 110 ° C. for 1.0 hour, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 16A was obtained in a yield of 75%. The weight average molecular weight Mw of the obtained copolymer 16A was 161,000, and the PDI was 3.9.

<Synthesis Example 17A: Synthesis of Copolymer 17A>

In a nitrogen atmosphere, in a 50 mL two-necked eggplant flask, as a monomer, 3,7-di (2-bromo-3-dodecylthiophene-5-5) obtained by referring to the method described in US Patent Application Publication No. 2012/0227812 was obtained. Il) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiazazole (Compound A1) (29.2 mg, 0.032 mmol), known literature (Materials Chemistry C, 2015, 3) , 8916-8925), 2,2'-bis- (5-bromo-thiophen-2-yl) -2,5-difluoro-1,4-phenylene (Compound A13) (14.1 mg) , 0.032 mmol), and 4,8-bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2, obtained with reference to the method described in JP-A-2014-501032. 6-Bis (trimethylstanyl) -benzo [1,2-b: 4,5-b'] dithiophene (Compound D1) (74.5 mg, 0.066 mmol) was added, and tris (dibenzylideneacetone) dipalladium was added. Add chloroform complex (2.7 mg, 4.0 mol%), tris (2-methylphenyl) phosphine (3.2 mg, 16 mol%) and chlorobenzene (5.0 mL) at 100 ° C for 1 hour, followed by 110 ° C. The mixture was stirred for 1 hour. As a terminal treatment, trimethyl (phenyl) tin (0.03 mL) and chlorobenzene (5.0 mL) were added to the reaction solution, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, and then bromobenzene (1.0 mL) was further added. The reaction solution was poured into methanol by heating and stirring at 110 ° C. for 1.0 hour, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 17A was obtained in 79% yield. The weight average molecular weight Mw of the obtained copolymer 17A was 98,000, and the PDI was 3.7.

<Synthesis Example 18A: Synthesis of Copolymer 18A>

In a nitrogen atmosphere, in a 50 mL two-necked eggplant flask, as a monomer, 3,7-di (2-bromo-3-dodecylthiophene-5-5) obtained by referring to the method described in US Patent Application Publication No. 2012/0227812 was obtained. Il) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A1) (29.2 mg, 0.032 mmol), with reference to Japanese Patent Application Laid-Open No. 2014-501032. 4,7-Bis- (5-bromo-thiophen-2-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound A2) (8.0 mg, 0.016 mmol) , 2,2'-bis- (5-bromo-thiophen-2-yl) -2,5-difluoro-1, obtained with reference to known literature (Materials Chemistry C, 2015, 3, 8916-8925), 4-Phenylene (Compound A13) (7.1 mg, 0.016 mmol) and 4,8-bis- [5- (2-hexyldecyl) obtained by referring to the methods described in JP-A-2014-501032. ) -Thiophen-2-yl] -2,6-bis (trimethylstanyl) -benzo [1,2-b: 4,5-b'] dithiophene (Compound D1) (74.5 mg, 0.066 mmol) Add tris (dibenzylideneacetone) dipalladium chloroform complex (2.7 mg, 4.0 mol%), tris (2-methylphenyl) phosphine (3.2 mg, 16 mol%), and chlorobenzene (5.0 mL). The mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 1 hour. As a terminal treatment, trimethyl (phenyl) tin (0.03 mL) and chlorobenzene (5.0 mL) were added to the reaction solution, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, and then bromobenzene (1.0 mL) was further added. The reaction solution was poured into methanol by heating and stirring at 110 ° C. for 1.0 hour, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 18A was obtained in a yield of 78%. The weight average molecular weight Mw of the obtained copolymer 18A was 116,000, and the PDI was 4.5.

<Synthesis Example 19A: Synthesis of Copolymer 19A>
[Synthesis example: Synthesis of 4,7-bis (3-dodecyl [2,2'-bithiophene] -5-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (compound T28)]

2-Tributylstanylthiophene (Compound T27) (0.73 g, 1.96 mmol) in a 50 mL two-necked flask, 4,7-bis (5-bromo-4) obtained with reference to Japanese Patent Application Laid-Open No. 2014-501032. -Dodecylthiophen-2-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound T28) (0.65 g, 0.78 mmol) was added, and nitrogen substitution was performed three times. Tetrakistriphenylphosphine palladium (37.5 mg, 0.03 mmol) was added and nitrogen substitution was performed twice. 8 mL of dehydrated toluene and 2 mL of dehydrated DMF were added, and the mixture was stirred at 115 ° C. for 3 hours. Toluene was distilled off after cooling to room temperature. 20 mL of methanol was added, the mixture was stirred, and the mixture was filtered off. The filtered solid was sprinkled with methanol three times, washed and dried. The obtained orange solid was dissolved by heating in 50 mL of chloroform and purified by a short-pass silica gel column. By distilling off the solvent and drying under reduced pressure, 4,7-bis (3-dodecyl [2,2'-bithiophene] -5-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound T29) was obtained in an amount of 0.55 g and a yield of 84%.

[Synthetic example: 4,7-bis (5'-bromo-3-dodecyl [2,2'-bithiophene] -5-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound A14) ) Synthesis]

4,7-Bis (3-dodecyl [2,2'-bithiophene] -5-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound T29) (0.55 g) in a 2 L eggplant flask , 0.66 mmol) was added, 10.5 mL of chloroform and 3.5 mL of acetic acid were added, and the mixture was stirred. N-Bromosuccinimide (234 mg, 1.31 mmol) was added, and the mixture was heated with stirring at 75 ° C. for 3 hours. After cooling to room temperature, 20 mL of methanol was added, the mixture was stirred, and the mixture was filtered off. The filtered solid was sprinkled with methanol three times, washed and dried. 4,7-Bis (5'-bromo-3-dodecyl [2,2'-bithiophene] -5-yl) -5,6-difluoro-benzo [1,2,5] by drying at 50 ° C. under reduced pressure. ] Thiadiazole (Compound A14) was obtained in 0.61 g with a yield of 93%.

[Synthesis example: Synthesis of copolymer 19A]

In a nitrogen atmosphere, in a 50 mL two-port eggplant flask, as a monomer, 3,7-di (2-bromo-3-dodecylthiophene-5-5) obtained by referring to the method described in US Patent Application Publication No. 2012/0227812 was obtained. Il) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A1) (29.8 mg, 0.033 mmol), 4,7 obtained by the method described above. -Bis (5'-bromo-3-dodecyl [2,2'-bithiophene] -5-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound A14) (32.8 mg, 0) .033 mmol) and 4,8-bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6- obtained by referring to the method described in JP-A-2014-501032. Bis (trimethylstanyl) -benzo [1,2-b: 4,5-b'] dithiophene (Compound D1) (74.5 mg, 0.066 mmol) was added, and tris (dibenzylideneacetone) dipalladium chloroform complex was added. Add (2.7 mg, 4.0 mol%), tris (2-methylphenyl) phosphine (3.2 mg, 16 mol%) and chlorobenzene (5.0 mL) at 100 ° C for 1 hour, followed by 110 ° C for 1 hour. Stirred. As a terminal treatment, trimethyl (phenyl) tin (0.03 mL) and chlorobenzene (5.0 mL) were added to the reaction solution, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, and then bromobenzene (1.0 mL) was further added. The reaction solution was poured into methanol by heating and stirring at 110 ° C. for 1.0 hour, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 19A was obtained in a yield of 81%. The weight average molecular weight Mw of the obtained copolymer 19A was 222,000, and the PDI was 4.0.

<Synthesis Example 20A: Synthesis of Copolymer 20A>
[Synthesis example: Synthesis of 4,7-bis (4'-dodecyl [2,2'-bithiophene] -5-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (compound T31)]

2-trimethylstanyl-4-dodecylthiophene (Compound T30) (1.50 g, 3.61 mmol) obtained in a 50 mL two-necked flask with reference to the method described in US Patent Application Publication No. 2012/0227812, special table. 4,7-Bis- (5-bromo-thiophen-2-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound A2) (Compound A2) obtained with reference to Publication No. 2014-501032. 0.71 g (1.44 mmol) was added, and nitrogen substitution was carried out three times. Tetrakistriphenylphosphine palladium (50.0 mg, 0.04 mmol) was added and nitrogen substitution was performed twice. 12 mL of dehydrated toluene and 3 mL of dehydrated DMF were added, and the mixture was stirred at 115 ° C. for 3 hours. Toluene was distilled off after cooling to room temperature. 30 mL of methanol was added, the mixture was stirred, and the mixture was filtered off. The filtered solid was sprinkled with methanol three times, washed and dried. The obtained orange solid was dissolved by heating in 50 mL of chloroform and purified by a short-pass silica gel column. By distilling off the solvent and drying under reduced pressure, 4,7-bis (4'-dodecyl [2,2'-bithiophene] -5-yl) -5,6-difluoro-benzo [1,2,5] Thiadiazole (Compound T31) was obtained in 0.98 g with a yield of 82%.

[Synthetic example: 4,7-bis (5'-bromo-4'-dodecyl [2,2'-bithiophene] -5-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (compound) Synthesis of A15)]

4,7-Bis (4'-dodecyl [2,2'-bithiophene] -5-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound T31) (0. 63 g, 0.76 mmol) was added, 12.0 mL of chloroform and 4.0 mL of acetic acid were added, and the mixture was stirred. N-Bromosuccinimide (283 mg, 1.52 mmol) was added, and the mixture was heated with stirring at 75 ° C. for 3 hours. After cooling to room temperature, 20 mL of methanol was added, the mixture was stirred, and the mixture was filtered off. The filtered solid was sprinkled with methanol three times, washed and dried. By drying at 50 ° C. under reduced pressure, 4,7-bis (5'-bromo-4'-dodecyl [2,2'-bithiophene] -5-yl) -5,6-difluoro-benzo [1,2, 5] Thiadiazole (Compound A15) was obtained in 0.72 g with a yield of 95%.

[Synthesis example: Synthesis of copolymer 20A]

In a nitrogen atmosphere, in a 50 mL two-port eggplant flask, as a monomer, 3,7-di (2-bromo-3-dodecylthiophene-5-5) obtained by referring to the method described in US Patent Application Publication No. 2012/0227812 was obtained. Il) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A1) (29.8 mg, 0.033 mmol), 4,7 obtained by the method described above. -Bis (5'-bromo-4'-dodecyl [2,2'-bithiophene] -5-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound A15) (32.8 mg, 0.033 mmol) and 4,8-bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6 obtained with reference to the method described in JP-A-2014-50132. -Bis (trimethylstanil) -benzo [1,2-b: 4,5-b'] dithiophene (Compound D1) (74.5 mg, 0.066 mmol) was added, and tris (dibenzylideneacetone) dipalladium chloroform was added. Add the complex (2.7 mg, 4.0 mol%), tris (2-methylphenyl) phosphine (3.2 mg, 16 mol%) and chlorobenzene (5.0 mL) for 1 hour at 100 ° C, followed by 1 at 110 ° C. Stirred for hours. As a terminal treatment, trimethyl (phenyl) tin (0.03 mL) and chlorobenzene (5.0 mL) were added to the reaction solution, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, and then bromobenzene (1.0 mL) was further added. The reaction solution was poured into methanol by heating and stirring at 110 ° C. for 1.0 hour, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 20A was obtained in a yield of 83%. The weight average molecular weight Mw of the obtained copolymer 20A was 200,000, and the PDI was 4.4.

<Synthesis Example 21A: Synthesis of Copolymer 21A>

In a nitrogen atmosphere, in a 50 mL two-port eggplant flask, as a monomer, 3,7-di (2-bromo-3-dodecylthiophene-5-5) obtained by referring to the method described in US Patent Application Publication No. 2012/0227812 was obtained. Il) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A1) (40.0 mg, 0.044 mmol), 4,7 obtained by the method described above. -Bis (5'-bromo-3-dodecyl [2,2'-bithiophene] -5-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound A14) (18.9 mg, 0) .019 mmol) and 4,8-bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6- obtained by referring to the method described in JP-A-2014-501032. Bis (trimethylstanyl) -benzo [1,2-b: 4,5-b'] dithiophene (Compound D1) (74.5 mg, 0.066 mmol) was added, and tris (dibenzylideneacetone) dipalladium chloroform complex was added. Add (2.7 mg, 4.0 mol%), tris (2-methylphenyl) phosphine (3.2 mg, 16 mol%) and chlorobenzene (5.0 mL) at 100 ° C for 1 hour, followed by 110 ° C for 1 hour. Stirred. As a terminal treatment, trimethyl (phenyl) tin (0.03 mL) and chlorobenzene (5.0 mL) were added to the reaction solution, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, and then bromobenzene (1.0 mL) was further added. The reaction solution was poured into methanol by heating and stirring at 110 ° C. for 1.0 hour, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 21A was obtained in 79% yield. The weight average molecular weight Mw of the obtained copolymer 21A was 86,000, and the PDI was 2.6.

<Synthesis Example 22A: Synthesis of Copolymer 22A>

3,7-Di (2-bromo-3-dodecylthiophene-5-5) obtained as a monomer in a 50 mL two-port eggplant flask under a nitrogen atmosphere by referring to the method described in US Patent Application Publication No. 2012/0227812. Il) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A1) (40.0 mg, 0.044 mmol), 4,7 obtained by the method described above. -Bis (5'-bromo-4'-dodecyl [2,2'-bithiophene] -5-yl) -5,6-difluoro-benzo [1,2,5] thiadiazole (Compound A15) (18.9 mg, 0.019 mmol) and 4,8-bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6 obtained with reference to the methods described in JP-A-2014-50132. -Bis (trimethylstanil) -benzo [1,2-b: 4,5-b'] dithiophene (Compound D1) (74.5 mg, 0.066 mmol) was added, and tris (dibenzylideneacetone) dipalladium chloroform was added. Add the complex (2.7 mg, 4.0 mol%), tris (2-methylphenyl) phosphine (3.2 mg, 16 mol%) and chlorobenzene (5.0 mL) for 1 hour at 100 ° C, followed by 1 at 110 ° C. Stirred for hours. As a terminal treatment, trimethyl (phenyl) tin (0.03 mL) and chlorobenzene (5.0 mL) were added to the reaction solution, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, and then bromobenzene (1.0 mL) was further added. The reaction solution was poured into methanol by heating and stirring at 110 ° C. for 1.0 hour, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 22A was obtained in 80% yield. The weight average molecular weight Mw of the obtained copolymer 22A was 145,000, and the PDI was 4.1.

<Example 1A: Fabrication and evaluation of photoelectric conversion element 1A>
[Preparation of composition for forming active layer]
As a p-type semiconductor compound, the copolymer 1A obtained in Synthesis Example 1A, and as an n-type semiconductor compound, a mixture of PC61BM (phenyl C61 butyric acid methyl ester) and PC71BM (phenyl C71 butyric acid methyl ester), which are fullerene compounds (Frontier Carbon Co., Ltd., nanom semiconductor E123) was dissolved in a mixed solvent of o-xylene and tetraline (volume ratio 9: 1) in a nitrogen atmosphere so as to have a concentration of 3.6% by mass. The mass ratio of the p-type semiconductor compound to the n-type semiconductor compound was set to p-type semiconductor compound: n-type semiconductor compound = 1: 2. The 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 prepare a composition for forming an active layer.

A glass substrate (manufactured by Geomatec) in which an indium tin oxide (ITO) transparent conductive film is patterned is ultrasonically cleaned with acetone, then ultrasonically cleaned with isopropanol, then dried with a nitrogen blow and UV-ozone treatment. went.

Next, a mixed solvent (volume ratio 100:) of 2-methoxyethanol (Aldrich) and ethanolamine (Aldrich) was added so that zinc acetate (II) dihydrate (Wako Pure Chemical Industries, Ltd.) had a concentration of 105 mg / mL. The solution (about 0.1 mL) dissolved in 3) was spin-coated at a rate of 3000 rpm, treated with UV-ozone, 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, cooled, and then spin-coated with the active layer coating composition (0.12 mL) prepared as described above. An active layer having a film thickness of about 200 nm was formed. Then, it was heated at 140 ° C. for 10 minutes on a hot plate. Next, the substrate on which the active layer was formed was taken out from the glove box, allowed to stand in the air (25 ° C., humidity 1% or less) for 3 hours under light shielding, and then brought back into the glove box.

Next, a 1.5 nm thick molybdenum trioxide (MoO3) film was formed on the active layer as a hole extraction layer, and then a 100 nm thick silver film was formed as an upper electrode by a resistance heating type vacuum deposition method. A 5 mm square photoelectric conversion element was produced by sequentially forming a film. The photoelectric conversion element 1A-1 thus produced was evaluated by measuring the current-voltage characteristics as described above, and the photoelectric conversion efficiency (PCE) was determined.

In addition, after taking out the substrate having the film formed up to the active layer from the glove box, instead of allowing it to stand in the air (25 ° C., humidity 1% or less) for 3 hours under light shielding, it is exposed to the fluorescent lamp and in the air (25). The photoelectric conversion element 1A-2 was produced in the same manner as the photoelectric conversion element 1A-1 except that the film was allowed to stand at ° C. and humidity of 1% or less) for 3 hours. The 1A-2 conversion efficiency of the photoelectric conversion element thus obtained was obtained, and the retention rate with respect to the conversion efficiency of the photoelectric conversion element 1A-1 whose active layer was not exposed (light-shielding) (conversion efficiency of the photoelectric conversion element 1A-2). / Conversion efficiency of photoelectric conversion element 1A-1) was calculated as light resistance. The results obtained are shown in Table 1.

<Reference Example 1A: Fabrication and evaluation of photoelectric conversion element 2A>
A photoelectric conversion element 2A was prepared and evaluated in the same manner as in Example 1A except that the copolymer 2A obtained in Synthesis Example 2A was used instead of the copolymer 1A. The results obtained are shown in Table 1.

<Reference Example 2A: Fabrication and evaluation of photoelectric conversion element 3A>
A photoelectric conversion element 3A was prepared and evaluated in the same manner as in Example 1A except that the copolymer 3A obtained in Synthesis Example 3A was used instead of the copolymer 1A. The results obtained are shown in Table 1.

<Example 2A: Fabrication and evaluation of photoelectric conversion element 4A>
A photoelectric conversion element 4A was prepared and evaluated in the same manner as in Example 1A except that the copolymer 4A obtained in Synthesis Example 4A was used instead of the copolymer 1A. The results obtained are shown in Table 1.

<Example 3A: Fabrication and evaluation of photoelectric conversion element 5A>
A photoelectric conversion element 5 was produced and evaluated in the same manner as in Example 1A except that the copolymer 5A obtained in Synthesis Example 5A was used instead of the copolymer 1A. The results obtained are shown in Table 1.

<Example 4A: Fabrication and evaluation of photoelectric conversion element 6A>
A photoelectric conversion element 6A was prepared and evaluated in the same manner as in Example 1A except that the copolymer 6A obtained in Synthesis Example 6A was used instead of the copolymer 1A. The results obtained are shown in Table 1.

<Example 5A: Fabrication and evaluation of photoelectric conversion element 7A>
A photoelectric conversion element 7A was prepared and evaluated in the same manner as in Example 1A except that the copolymer 6A obtained in Synthesis Example 7A was used instead of the copolymer 1A. The results obtained are shown in Table 1.

<Example 6A: Fabrication and evaluation of photoelectric conversion element 8A>
A photoelectric conversion element 8A was prepared and evaluated in the same manner as in Example 1A except that the copolymer 8A obtained in Synthesis Example 8A was used instead of the copolymer 1A. The results obtained are shown in Table 1.

<Example 7A: Fabrication and evaluation of photoelectric conversion element 9A>
A photoelectric conversion element 9A was prepared and evaluated in the same manner as in Example 1A except that the copolymer 9A obtained in Synthesis Example 9A was used instead of the copolymer 1A. The results obtained are shown in Table 1.

<Example 8A: Fabrication and evaluation of photoelectric conversion element 10A>
A photoelectric conversion element 10A was prepared and evaluated in the same manner as in Example 1A except that the copolymer 10A obtained in Synthesis Example 10A was used instead of the copolymer 1A. The results obtained are shown in Table 1.

<Example 9A: Fabrication and evaluation of photoelectric conversion element 11A>
A photoelectric conversion element 11A was prepared and evaluated in the same manner as in Example 1A except that the copolymer 11A obtained in Synthesis Example 11A was used instead of the copolymer 1A. The results obtained are shown in Table 1.

<Reference Example 3A: Fabrication and Evaluation of Photoelectric Conversion Element 12A>
A photoelectric conversion element 12A was prepared and evaluated in the same manner as in Example 1A except that the copolymer 12A obtained in Synthesis Example 12A was used instead of the copolymer 1A. The results obtained are shown in Table 1.

<Example 10A: Fabrication and evaluation of photoelectric conversion element 13A>
A photoelectric conversion element 13A was prepared and evaluated in the same manner as in Example 1A except that the copolymer 13A obtained in Synthesis Example 13A was used instead of the copolymer 1A. The results obtained are shown in Table 1.

<Reference Example 4A: Fabrication and evaluation of photoelectric conversion element 14A>
An attempt was made to prepare a photoelectric conversion element 14A by the same method as in Example 1A, except that the copolymer 14A obtained in Synthesis Example 14A was used instead of the copolymer 1A. However, the copolymer 14A did not dissolve in a solvent such as chloroform, toluene, orthodichlorobenzene, and a photoelectric conversion element could not be produced. Therefore, the photoelectric conversion efficiency and the light resistance could not be evaluated.

<Example 11A: Fabrication and evaluation of photoelectric conversion element 15A>
A photoelectric conversion element 15A was prepared and evaluated in the same manner as in Example 1A except that the copolymer 15A obtained in Synthesis Example 15A was used instead of the copolymer 1A. The results obtained are shown in Table 1.

<Example 12A: Fabrication and evaluation of photoelectric conversion element 16A>
A photoelectric conversion element 16A was prepared and evaluated in the same manner as in Example 1A except that the copolymer 16A obtained in Synthesis Example 16A was used instead of the copolymer 1A. The results obtained are shown in Table 1.

<Example 13A: Fabrication and evaluation of photoelectric conversion element 17A>
A photoelectric conversion element 17A was prepared and evaluated in the same manner as in Example 1A except that the copolymer 17A obtained in Synthesis Example 17A was used instead of the copolymer 1A. The results obtained are shown in Table 1.

<Example 14A: Fabrication and evaluation of photoelectric conversion element 18A>
A photoelectric conversion element 18A was prepared and evaluated in the same manner as in Example 1A except that the copolymer 18A obtained in Synthesis Example 18A was used instead of the copolymer 1A. The results obtained are shown in Table 1.

<Example 15A: Fabrication and evaluation of photoelectric conversion element 19A>
A photoelectric conversion element 19A was prepared and evaluated in the same manner as in Example 1A except that the copolymer 19A obtained in Synthesis Example 19A was used instead of the copolymer 1A. The results obtained are shown in Table 1.

<Example 16A: Fabrication and evaluation of photoelectric conversion element 20A>
A photoelectric conversion element 20A was prepared and evaluated in the same manner as in Example 1A except that the copolymer 20A obtained in Synthesis Example 20A was used instead of the copolymer 1A. The results obtained are shown in Table 1.

<Example 17A: Fabrication and evaluation of photoelectric conversion element 21A>
A photoelectric conversion element 21A was prepared and evaluated in the same manner as in Example 1A except that the copolymer 21A obtained in Synthesis Example 21A was used instead of the copolymer 1A. The results obtained are shown in Table 1.

<Example 18A: Fabrication and evaluation of photoelectric conversion element 22A>
A photoelectric conversion element 22A was prepared and evaluated in the same manner as in Example 1A except that the copolymer 22A obtained in Synthesis Example 22A was used instead of the copolymer 1A. The results obtained are shown in Table 1.

From the results in Table 1, the conversion efficiencies of the photoelectric conversion elements obtained by Reference Example 1A and Reference Example 2A were 5.75% and 0.76%, respectively, whereas the copolymer 2 of Reference Example 1A had a conversion efficiency of 5.75% and 0.76%, respectively. The conversion efficiency of the photoelectric conversion element according to Example 1A using the copolymer 1 having both the constitutional unit and the constitutional unit of the copolymer 3 of Reference Example 2A is 8.76%, and the two repetitions. It can be confirmed that the conversion efficiency is significantly improved by using the unit. Further, the retention rates of the photoelectric conversion elements obtained in Reference Example 1A and Reference Example 2A were 79% and 54%, respectively, whereas the retention rates of the photoelectric conversion elements obtained in Example 1A were It is 96%, and it can be confirmed that not only the conversion efficiency but also the light resistance is improved.

^{Further, since the copolymer 14A in which R 1 to} R ⁴ represented by the formula (I) are all hydrogen atoms was not dissolved in a solvent such as chloroform, toluene, orthodichlorobenzene, a photoelectric conversion element could not be manufactured. Furthermore, the conversion efficiency of the photoelectric conversion element according to Reference Example 3A using the copolymer 12A in which ^{R 1 to} R ^{4 were all monovalent organic groups was 5.39%, and the exposure resistance was 57%.} against a was the, a conversion efficiency are both high values of the photoelectric conversion device according to example 1A and example 10A using the selected copolymers 1A and copolymers 13A in accordance with the present invention the group R ¹ to R ⁴ It was. From this result, like the copolymer according to the first embodiment, it has a structural unit represented by the formula (I) and the formula (II), and further, the substituent on the 5-membered ring in the formula (I). It can be confirmed that high conversion efficiency and high light resistance can be obtained by adjusting the position. Further, it can be seen that the photoelectric conversion elements according to Examples 2A to 18A also have high conversion efficiency and high light resistance as in Example 1A.

<Synthesis Example 1B: Synthesis of Copolymer 1B>

3,7-Di (2-bromo-3-dodecylthiophene-) obtained as a monomer in a 50 mL twin-necked eggplant flask under a nitrogen atmosphere by referring to the method described in Japanese Patent Application Publication No. 2012/0227812. 5-Il) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiazazole (Compound A1) (60.0 mg, 0.066 mmol), publicly known literature (J. Am. Chem) Soc., 2011, 133,9638-9641), 4,8-bis-[(4,5-dihexyl) -thiophen-2-yl] -2,6-bis (Trimethylstanyl) -benzo [1,2-b: 4,5-b'] dithiophene (Compound B1) (69.0 mg, 0.068 mmol) was added, and tetrakis (triphenylphosphine) palladium (0) ( 2.8 mg, 3.00 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 3.6 mg, 1.53 mol%), toluene (4.8 mL), and N, N- Dimethylformamide (1.2 mL) was added and stirred at 100 ° C. for 1 hour, followed by 110 ° C. for 2 hours. The reaction mixture is diluted 2-fold with toluene and heated and stirred at 110 ° C. for an additional 0.5 hours, then trimethyl (phenyl) tin (0.03 mL) is added as a terminal treatment, and the reaction mixture is heated and stirred at 110 ° C. for 1.0 hour. Then, bromobenzene (1.00 mL) was further added, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, the reaction solution was poured into methanol, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 1B was obtained in a yield of 61%. The weight average molecular weight Mw of the obtained copolymer 1B was 34,000, and the PDI was 1.7.

<Synthesis Example 2B: Synthesis of Copolymer 2B>

3,7-di (2-bromo-3-dodecylthiophene-) obtained as a monomer in a 50 mL two-necked eggplant flask under a nitrogen atmosphere by referring to the method described in Japanese Patent Application Publication No. 2012/0227812. 5-Il) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A1) (60.0 mg, 0.066 mmol), known literature (ACS Macro Lett., 4,8-Bis- [5- (2-butyloctyl) -thiophen-2-yl] -2,6-bis (trimethylsta) obtained with reference to the method described in 2013, 2,605-608). Nyl) -benzo [1,2-b: 4,5-b'] dithiophene (Compound D2) (68.0 mg, 0.067 mmol) was added, and tetrakis (triphenylphosphine) palladium (0) (2.3 mg) was added. , 3.00 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 3.0 mg, 1.53 mol%), toluene (4.0 mL), and N, N-dimethylformamide ( 1.0 mL) was added, and the mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 2 hours. The reaction mixture is diluted 2-fold with toluene and heated and stirred at 110 ° C. for an additional 0.5 hours, then trimethyl (phenyl) tin (0.03 mL) is added as a terminal treatment, and the reaction mixture is heated and stirred at 110 ° C. for 1.0 hour. Then, bromobenzene (1.00 mL) was further added, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, the reaction solution was poured into methanol, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 2 was obtained in a yield of 76%. The weight average molecular weight Mw of the obtained copolymer 2 was 42,000, and the PDI was 2.4.

<Synthesis Example 3B: Synthesis of Copolymer 3B>

3,7-Di (2-bromo-3-dodecylthiophene-) obtained as a monomer in a 50 mL two-port eggplant flask under a nitrogen atmosphere by referring to the method described in Japanese Patent Application Publication No. 2012/0227812. 5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A1) (60.0 mg, 0.066 mmol), refer to the method described in Patent 5698371. 4,8-Bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6-bis (trimethylstanyl) -benzo [1,2-b: 4,5 -B'] Dithiophene (Compound D1) (74.7 mg, 0.067 mmol) was added, and tris (dibenzylideneacetone) dipalladium chloroform complex (2.7 mg, 4.00 mol%), tris (2-methylphenyl). Phosphine (6.4 mg, 32.00 mol%) and chlorobenzene (5.0 mL) were added, and the temperature was raised from 45 ° C. to 105 ° C. every 5 minutes, and after 1 hour, the temperature was raised to 115 ° C. After 3 hours, the temperature was raised to 130 ° C. and the mixture was stirred for 2.5 hours. The reaction mixture is diluted 2-fold with chlorobenzene, and as a terminal treatment, trimethyl (phenyl) tin (0.03 mL) is added, the mixture is heated and stirred at 130 ° C. for 1.5 hours, and bromobenzene (1.00 mL) is further added. The mixture was heated and stirred at 130 ° C. for 2.0 hours. The reaction solution was poured into methanol, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred for 30 minutes at room temperature and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 3B was obtained in a yield of 72%. The weight average molecular weight Mw of the obtained copolymer 3B was 150,000, and the PDI was 4.5.

<Synthesis Example 4B: Synthesis of Copolymer 4B>

In a nitrogen atmosphere, 3,7-di (2-bromo-3-dodecylthiophene-) was obtained as a monomer in a 50 mL two-necked eggplant flask by referring to the method described in Japanese Patent Application Publication No. 2012/0227812. 5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A1) (59.6 mg, 0.066 mmol), refer to the method described in Patent 5698371. 4,8-Bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6-bis (trimethylstanyl) -benzo [1,2-b: 4,5 -B'] Dithiophene (Compound D1) (37.3 mg, 0.033 mmol) was added, and 4,8-bis- obtained by referring to the method described in (Macromolecules, 2011, 44, 7207-7219). [(2-Hexyldecyl) oxy] -2,6-bis (trimethylstanyl) -benzo [1,2-b: 4,5-b'] dithiophene (Compound B4) (32.9 mg, 0.033 mmol) , Tris (dibenzylideneacetone) dipalladium chloroform complex (2.73 mg, 4.00 mol%), tris (2-methylphenyl) phosphine (3.21 mg, 16.00 mol%), chlorobenzene (5.0 mL). Was added, and the mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 2 hours. The reaction mixture is diluted 2-fold with toluene and heated and stirred at 110 ° C. for an additional 0.5 hours, then trimethyl (phenyl) tin (0.03 mL) is added as a terminal treatment, and the reaction mixture is heated and stirred at 110 ° C. for 1.0 hour. Then, bromobenzene (1.00 mL) was further added, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, the reaction solution was poured into methanol, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 4B was obtained in a yield of 82%. The weight average molecular weight Mw of the obtained copolymer 4B was 116,000, and the PDI was 4.5.

<Synthesis Example 5B: Synthesis of Copolymer 5B>

In a nitrogen atmosphere, in a 50 mL two-necked eggplant flask, 3,7-di (2-bromo-3-dodecylthiophene-) was obtained as a monomer by referring to the method described in Japanese Patent Application Publication No. 2012/0227812. 5-Il) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A1) (58.6 mg, 0.065 mmol), known literature (ACS Macro Lett., 4,8-Bis- [5- (2-octyldodecyl) -thiophen-2-yl] -2,6-bis (trimethylsta) obtained with reference to the method described in 2013, 2,605-608). Nyl) -benzo [1,2-b: 4,5-b'] dithiophene (Compound B5) (80.5 mg, 0.065 mmol) was added, and tris (dibenzylideneacetone) dipalladium chloroform complex (2.7 mg) was added. , 4.00 mol%), tris (2-methylphenyl) phosphine (6.3 mg, 32.00 mol%) and chlorobenzene (5.0 mL) were added, and the mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 2 hours. .. The reaction mixture was diluted 2-fold with chlorobenzene and heated and stirred at 110 ° C. for another 1 hour. Then, as a terminal treatment, trimethyl (phenyl) tin (0.03 mL) was added and heated and stirred at 110 ° C. for 1.0 hour. Further, bromobenzene (1.0 mL) was added, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, the reaction solution was poured into methanol, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 5 was obtained in a yield of 83%. The weight average molecular weight Mw of the obtained copolymer 5 was 119,000, and the PDI was 4.2.

<Synthesis Example 6B: Synthesis of Copolymer 6B>
[Synthesis example: Synthesis of 4-tetradecyl-2-trimethylstanylthiophene (Compound T2)]

2,2,6,6-tetramethylpiperidin (2.18 g, 15 mmol) was added to a 50 mL two-necked flask, and nitrogen substitution was performed three times. 10 mL of dry THF was added, and the mixture was cooled to −78 ° C. in a dry ice acetone bath. n-Butyllithium (1.6M, 8.9 mL, 14.3 mmol) was added dropwise at −78 ° C., the mixture was stirred for 30 minutes, and then the temperature was raised to 0 ° C. in an ice bath. On the other hand, 3-tetradecylthiophene (Compound T1) (4.3 g, 15 mmol) was added to a 500 mL four-necked flask, and nitrogen substitution was carried out three times. 190 mL of dry THF was added, and the mixture was cooled to −40 ° C. in a dry ice acetone bath. The previously prepared LiTMP was slowly added dropwise at −40 ° C., and after the completion of the addition, the mixture was stirred for another 1 hour, trimethyltin chloride (1 Min THF 15 mL, 15 mmol) was added dropwise, and the mixture was stirred for 30 minutes. 100 mL of distilled water was added to quench the reaction, and the aqueous layer was extracted once with hexane. The organic layer was washed 3 times with water and dried over anhydrous sodium sulfate. The solvent was distilled off with an evaporator and dried under reduced pressure (oil pump) at 40 ° C. to obtain 4-tetradecyl-2-trimethylstanylthiophene (Compound T2). As a result of proton NMR, the purity of the tin body was 70%.

[Synthesis example: Synthesis of 3,7-di (3-tetradecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound T4) ]

4-Tetradecyl-2-trimethylstanylthiophene (Compound T2) (2.37 g (P.70%) 3.75 mmol), 3,7-dibromo-naphtho [1,2-c: 5,] in a 50 mL two-necked flask. 6-c] Bis [1,2,5] thiadiazole (Compound T3) (603 mg, 1.5 mmol) was added, and nitrogen substitution was performed three times. Tetrakistriphenylphosphine palladium (34.9 mg, 0.02 mmol) was added and nitrogen substitution was performed twice. 70 mL of dehydrated toluene and 7 mL of dehydrated DMF were added, and the mixture was stirred at 115 ° C. for 3 hours. Toluene was distilled off after cooling to room temperature. 20 mL of ethyl acetate was added, the mixture was stirred, and the mixture was filtered off. The separated solid was sprinkled with ethyl acetate three times, washed and dried. The obtained orange solid was dissolved by heating in 300 mL of chloroform and purified by a short-pass silica gel column. By distilling off the solvent and drying under reduced pressure, 3,7-di (3-tetradecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5 ] Thiadiazole (Compound T4) was obtained in 1.13 g with a yield of 94%.

[Synthetic example: 3,7-di (2-bromo-3-tetradecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (compound) Synthesis of A4)]

3,7-Di (3-tetradecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound T4) (1) in a 2L eggplant flask .13 g, 1.42 mmol) was added, 1000 mL of chloroform was added, and the mixture was heated and stirred using a dryer. After cooling to room temperature and shading the flask with aluminum foil, a chloroform solution of bromine (493 mg, 3.09 mmol) was quickly added dropwise at room temperature. After stirring at room temperature for 1 hour, 90% of the solvent was distilled off. The obtained red slurry liquid was filtered under reduced pressure and sprinkled with chloroform three times for washing. By drying at 50 ° C. under reduced pressure, 3,7-di (2-bromo-3-tetradecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2, 5] Thiadiazole (Compound A4) was obtained in 1.34 g with a yield of 98%.

[Synthesis Example 6B: Synthesis of Copolymer 6B]

In a nitrogen atmosphere, in a 50 mL two-necked eggplant flask, as a monomer, 3,7-di (2-bromo-3-tetradecylthiophene-5-yl) -naphtho [1,2-c: obtained by the above method. 5,6-c] bis [1,2,5] thiadiazole (Compound A4) (38.4 mg, 0.040 mmol), the method described in the known literature (ACS Macro Let., 2013, 2,605-608). 4,8-Bis- [5- (2-butyloctyl) -thiophen-2-yl] -2,6-bis (trimethylstanyl) -benzo [1,2-b: 4, obtained as a reference 5-b'] Dithiophene (Compound D2) (40.7 mg, 0.040 mmol) was added, and tris (dibenzylideneacetone) dipalladium chloroform complex (1.65 mg, 4.00 mol%) and tris (2-methylphenyl) were added. ) Phosphine (1.95 mg, 16.00 mol%) and chloroform (3.0 mL) were added, and the mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 2 hours. The reaction mixture is diluted 2-fold with chlorobenzene and stirred at 110 ° C. for an additional 0.5 hour, then trimethyl (phenyl) tin (0.03 mL) is added as a terminal treatment, and the mixture is heated and stirred at 110 ° C. for 1.0 hour. Then, bromobenzene (1.00 mL) was further added, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, the reaction solution was poured into methanol, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 6B was obtained in a yield of 76%. The weight average molecular weight Mw of the obtained copolymer 6B was 270,000, and the PDI was 8.7.

<Synthesis Example 7B: Synthesis of Copolymer 7B>

In a nitrogen atmosphere, in a 50 mL two-necked eggplant flask, as a monomer, 3,7-di (2-bromo-3-tetradecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A4) (62.0 mg, 0.065 mmol), the method described in the known literature (ACS Macro Let., 2013, 2,605-608). 4,8-Bis- [5- (2-butyloctyl) -thiophen-2-yl] -2,6-bis (trimethylstanyl) -benzo [1,2-b: 4, obtained as a reference 5-b'] Dithiophene (Compound D2) (32.9 mg, 0.032 mmol), 4,8-bis- [5-(5-( 2-Hexyldecyl) -thiophen-2-yl] -2,6-bis (trimethylstanyl) -benzo [1,2-b: 4,5-b'] dithiophene (Compound D1) (36.5 mg, 0) .032 mmol) is added, and tris (dibenzylideneacetone) dipalladium chloroform complex (2.7 mg, 4.00 mol%), tris (2-methylphenyl) phosphene (6.3 mg, 32.00 mol%), chlorobenzene (5). .0 mL) was added and stirred at 100 ° C. for 1 hour, followed by 110 ° C. for 2 hours. The reaction mixture was diluted 2-fold with chlorobenzene and heated and stirred at 110 ° C. for another 1 hour. Then, as a terminal treatment, trimethyl (phenyl) tin (0.03 mL) was added and heated and stirred at 110 ° C. for 1.0 hour. Further, bromobenzene (1.0 mL) was added, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, the reaction solution was poured into methanol, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 7B was obtained in a yield of 86%. The weight average molecular weight Mw of the obtained copolymer 7B was 367,000 K, and the PDI was 8.2.

<Synthesis Example 8B: Synthesis of Copolymer 8B>

In a nitrogen atmosphere, in a 50 mL two-necked eggplant flask, as a monomer, 3,7-di (2-bromo-3-tetradecylthiophene-5-yl) -naphtho [1,2-c: obtained by the above method. 5,6-c] Bis [1,2,5] Thiadiazole (Compound A4) (62.0 mg, 0.065 mmol), obtained by referring to the method described in Japanese Patent Application Laid-Open No. 2014-501032 4 , 8-bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6-bis (trimethylstanyl) -benzo [1,2-b: 4,5-b'] dithiophene ( Compound D1) (73.0 mg, 0.065 mmol) was added, and tris (dibenzylideneacetone) dipalladium chloroform complex (2.7 mg, 4.00 mol%) and tris (2-methylphenyl) phosphine (6.3 mg, 32.00 mol%) and chloroform (5.0 mL) were added, and the mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 2 hours. The reaction mixture was diluted 2-fold with chlorobenzene and heated and stirred at 110 ° C. for another 1 hour. Then, as a terminal treatment, trimethyl (phenyl) tin (0.03 mL) was added and heated and stirred at 110 ° C. for 1.0 hour. Further, bromobenzene (1.0 mL) was added, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, the reaction solution was poured into methanol, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 8B was obtained in 90% yield. The weight average molecular weight Mw of the obtained copolymer 8B was 291,000, and the PDI was 6.4.

<Synthesis Example 9B: Synthesis of Copolymer 9B>

In a nitrogen atmosphere, in a 50 mL two-necked eggplant flask, as a monomer, 3,7-di (2-bromo-3-tetradecylthiophene-5-yl) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A4) (60.7 mg, 0.063 mmol), the method described in the known literature (ACS Macro Let., 2013, 2,605-608). 4,8-Bis- [5- (2-octyldodecyl) -thiophen-2-yl] -2,6-bis (trimethylstanyl) -benzo [1,2-b: 4, obtained as a reference 5-b'] Dithiophene (Compound B5) (78.5 mg, 0.063 mmol) was added, and tris (dibenzylideneacetone) dipalladium chloroform complex (2.6 mg, 4.00 mol%) and tri-1-naphthylphosphine were added. (8.3 mg, 32.00 mol%) and chlorobenzene (5.0 mL) were added, and the mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 2 hours. The reaction mixture was diluted 2-fold with chlorobenzene and heated and stirred at 110 ° C. for another 1 hour. Then, as a terminal treatment, trimethyl (phenyl) tin (0.03 mL) was added and heated and stirred at 110 ° C. for 1.0 hour. Further, bromobenzene (1.0 mL) was added, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, the reaction solution was poured into methanol, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 9B was obtained in a yield of 85%. The weight average molecular weight Mw of the obtained copolymer 9B was 261,000, and the PDI was 5.6.

<Synthesis Example 10B: Synthesis of Copolymer 10B>

3,7-Di (2-bromo-3-hexylthiophene-) obtained as a monomer in a 50 mL two-necked eggplant flask under a nitrogen atmosphere by referring to the method described in Japanese Patent Application Publication No. 2012/0227812. 5-Il) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiazazole (Compound A17) (40.0 mg, 0.054 mmol), publicly known literature (J. Am. Chem) Soc., 2011, 133,9638-9641), 4,8-bis-[(4,5-dihexyl) -thiophen-2-yl] -2,6-bis (Trimethylstanyl) -benzo [1,2-b: 4,5-b'] dithiophene (Compound B1) (57.0 mg, 0.056 mmol) was added, and tetrakis (triphenylphosphine) palladium (0) ( 2.3 mg, 3.00 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 3.0 mg, 1.53 mol%), toluene (4.0 mL), and N, N- Dimethylformamide (1.0 mL) was added and stirred at 100 ° C. for 1 hour, followed by 110 ° C. for 2 hours. The reaction mixture is diluted 2-fold with toluene and heated and stirred at 110 ° C. for an additional 0.5 hours, then trimethyl (phenyl) tin (0.03 mL) is added as a terminal treatment, and the reaction mixture is heated and stirred at 110 ° C. for 1.0 hour. Then, bromobenzene (1.00 mL) was further added, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, the reaction solution was poured into methanol, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 10B was obtained in a yield of 51%. The weight average molecular weight Mw of the obtained copolymer 10B was 24,000, and the PDI was 1.9.

<Synthesis Example 11B: Synthesis of Copolymer 11B>

3,7-Di (2-bromo-3-hexylthiophene-) obtained as a monomer in a 50 mL two-necked eggplant flask under a nitrogen atmosphere by referring to the method described in Japanese Patent Application Publication No. 2012/0227812. 5-Il) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A17) (40.0 mg, 0.054 mmol), Japan Special Table 2014-501032 4,8-Bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6-bis (trimethylstanyl) -benzo [1, 2-b: 4,5-b'] dithiophene (Compound D1) (63.0 mg, 0.056 mmol) was added, and tetrakis (triphenylphosphine) palladium (0) (2.3 mg, 3.00 mol%), Triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (manufactured by Aldrich, 3.0 mg, 1.53 mol%), toluene (4.0 mL), and N, N-dimethylformamide (1.0 mL) were added. The mixture was stirred at 100 ° C. for 1 hour and then at 110 ° C. for 2 hours. The reaction mixture is diluted 2-fold with toluene and heated and stirred at 110 ° C. for an additional 0.5 hours, then trimethyl (phenyl) tin (0.03 mL) is added as a terminal treatment, and the reaction mixture is heated and stirred at 110 ° C. for 1.0 hour. Then, bromobenzene (1.00 mL) was further added, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, the reaction solution was poured into methanol, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 11B was obtained in a yield of 51%. The weight average molecular weight Mw of the obtained copolymer 11B was 38,000, and the PDI was 2.3.

<Synthesis Example 12B: Synthesis of Copolymer 12B>

3,7-di (2-bromo-3-dodecylthiophene-5-5) obtained as a monomer in a 50 mL two-necked eggplant flask under a nitrogen atmosphere by referring to the method described in US Patent Application Publication No. 2012/0227812. Il) -naphtho [1,2-c: 5,6-c] bis [1,2,5] thiadiazole (Compound A1) (59.6 mg, 0.066 mmol), and JP-A-2014-501032. 4,8-Bis- [5- (2-hexyldecyl) -thiophen-2-yl] -2,6-bis (trimethylstanyl) -benzo [1,2-b] obtained with reference to the above method. : 4,5-b'] Dithiophene (Compound D1) (74.5 mg, 0.066 mmol) was added, and tetrakis (triphenylphosphine) palladium (0) (2.3 mg, 3.00 mol%) and triphenylphosphine were added. Non-uniform palladium complex catalyst Pd-EnCatTPP30 (manufactured by Aldrich, 3.0 mg, 1.53 mol%), toluene (4.0 mL), and N, N-dimethylformamide (1.0 mL) were added and at 100 ° C. The mixture was stirred for 1 hour and then at 110 ° C. for 2 hours. The reaction mixture is diluted 2-fold with toluene and heated and stirred at 110 ° C. for an additional 0.5 hours, then trimethyl (phenyl) tin (0.03 mL) is added as a terminal treatment, and the reaction mixture is heated and stirred at 110 ° C. for 1.0 hour. Then, bromobenzene (1.00 mL) was further added, and the mixture was heated and stirred at 110 ° C. for 1.0 hour, the reaction solution was poured into methanol, and the precipitated precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added, and the mixture was stirred at room temperature for 1 hour and passed through a short column of acidic silica gel. By concentrating the solution, the desired copolymer 12B was obtained in a yield of 87%. The weight average molecular weight Mw of the obtained copolymer 12B was 52,000, and the PDI was 2.2.

Hereinafter, Examples 1B to 10B will be read as Reference Examples 3B to 12B.
<Example 1B: Fabrication and evaluation of photoelectric conversion element>
[Preparation of composition for forming active layer]
As a p-type semiconductor compound, the copolymer 1B obtained in Synthesis Example 1B, and as an n-type semiconductor compound, a mixture of PC61BM (phenyl C61 butyric acid methyl ester) and PC71BM (phenyl C71 butyric acid methyl ester), which are fullerene compounds (Frontier Carbon Co., Ltd., nanom semiconductor E123) was dissolved in a mixed solvent of o-xylene and tetraline (volume ratio 9: 1) in a nitrogen atmosphere so as to have a concentration of 3.6% by mass. The mass ratio of the p-type semiconductor compound to the n-type semiconductor compound was set to p-type semiconductor compound: n-type semiconductor compound = 1: 2. The 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 prepare a composition for forming an active layer.

A glass substrate (manufactured by Geomatec) in which an indium tin oxide (ITO) transparent conductive film is patterned is ultrasonically cleaned with acetone, then ultrasonically cleaned with isopropanol, then dried with a nitrogen blow and UV-ozone treatment. went.

Next, a mixed solvent (volume ratio 100:) of 2-methoxyethanol (Aldrich) and ethanolamine (Aldrich) was added so that zinc acetate (II) dihydrate (Wako Pure Chemical Industries, Ltd.) had a concentration of 105 mg / mL. The solution (about 0.1 mL) dissolved in 3) was spin-coated at a rate of 3000 rpm, treated with UV-ozone, 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, cooled, and then spin-coated with the active layer coating composition (0.12 mL) prepared as described above. An active layer having a film thickness of about 300 nm was formed. Then, it was heated at 140 ° C. for 10 minutes on a hot plate.

Next, a 1.5 nm thick molybdenum trioxide (MoO ₃ ) film is formed on the active layer as a hole extraction layer, and then a 100 nm thick silver film is formed as an upper electrode by a resistance heating type vacuum deposition method. To produce a 5 mm square photoelectric conversion element. The photoelectric conversion element 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 determined. The results obtained are shown in Table 2.

<Example 2B: Fabrication and evaluation of photoelectric conversion element>
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1B except that the copolymer 2 obtained in Synthesis Example 2B was used instead of the copolymer 1B. The results obtained are shown in Table 2.

<Example 3B: Fabrication and evaluation of photoelectric conversion element>
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1B except that the copolymer 3B obtained in Synthesis Example 3B was used instead of the copolymer 1B. The results obtained are shown in Table 2.

<Example 4B: Fabrication and evaluation of photoelectric conversion element>
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1B except that the copolymer 4B obtained in Synthesis Example 4B was used instead of the copolymer 1B. The results obtained are shown in Table 2.

<Example 5B: Fabrication and evaluation of photoelectric conversion element>
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1B except that the copolymer 5B obtained in Synthesis Example 5B was used instead of the copolymer 1B. The results obtained are shown in Table 2.

<Example 6B: Fabrication and evaluation of photoelectric conversion element>
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1B except that the copolymer 6B obtained in Synthesis Example 6B was used instead of the copolymer 1. The results obtained are shown in Table 2.

<Example 7: Fabrication and evaluation of photoelectric conversion element>
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1B except that the copolymer 7B obtained in Synthesis Example 7B was used instead of the copolymer 1B. The results obtained are shown in Table 2.

<Example 8B: Fabrication and evaluation of photoelectric conversion element>
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1B except that the copolymer 8B obtained in Synthesis Example 8B was used instead of the copolymer 1B. The results obtained are shown in Table 2.

<Example 9B: Fabrication and evaluation of photoelectric conversion element>
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1B except that the copolymer 9B obtained in Synthesis Example 9B was used instead of the copolymer 1B. The results obtained are shown in Table 2.

<Example 10B: Fabrication and evaluation of photoelectric conversion element>
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1B except that the copolymer 12B obtained in Synthesis Example 9B was used instead of the copolymer 1B. The results obtained are shown in Table 2.

<Reference Example 1B: Fabrication and evaluation of photoelectric conversion element>
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1B except that the copolymer 10B obtained in Synthesis Example 10B was used instead of the copolymer 1B. The results obtained are shown in Table 2.

<Reference Example 2B: Fabrication and evaluation of photoelectric conversion element>
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1B except that the copolymer 11B obtained in Synthesis Example 11B was used instead of the copolymer 1B. The results obtained are shown in Table 2.

表２中、Ｃ６はｎ−ヘキシル基、Ｃ１２はｎ−ドデシル基、Ｃ１４はｎ−テトラデシル基、Ｈは水素原子をそれぞれ表す。

In Table 2, C6 represents an n-hexyl group, C12 represents an n-dodecyl group, C14 represents an n-tetradecyl group, and H represents a hydrogen atom.

From the results in Table 2, the photoelectric conversion element according to Example 1B has obtained higher conversion efficiency than the photoelectric conversion element according to Reference Example 1B and Reference Example 2B. From this result, it can be seen that the conversion efficiency of the photoelectric conversion element is improved by using ^{R 1} and R ⁴ in the formula (I) as a specific aliphatic hydrocarbon group. Further, it can be seen that the conversion efficiency of the photoelectric conversion elements according to Examples 2B to 9B is significantly improved with respect to the photoelectric conversion elements according to Example 1B. ^{From this result, R 1} and R ⁴ in the formula (I) are ^{designated as specific aliphatic hydrocarbon groups, and R 21} , R ²² , R ²⁴ and R ²⁵ are designated as hydrogen atoms in the formula (XV), and R ^20. It can be seen that by using R ²³ as a branched aliphatic hydrocarbon group having a specific carbon number, steric hindrance in the copolymer can be suppressed and the conversion efficiency is significantly improved. Further, when Example 3B and Example 10B having the same repeating unit are compared, it can be seen that the conversion efficiency is further improved in Example 3B having a large molecular weight.

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 Weatherproof protective film 2 UV cut film 3, 9 Gas barrier film 4, 8 Getter film 5, 7 Encapsulant 6 Solar cell element 10 Back sheet 12 Base material 13 Solar cell unit 14 Thin-film solar cell

Claims (6)

It has a repeating unit represented by the following formula (I) and a repeating unit represented by the following formula (II) different from the above formula (I), and is represented by the above formula (I) with respect to the total number of repeating units. The ratio of the repeating unit to the total number of repeating units represented by the formula (II) is 1 , and the ratio of the number of repeating units represented by the formula (I) to the number of repeating units represented by the formula (II) (I). / II) is a copolymer having 0.1 or more and 9 or less.

(In formula (I), X ¹ and X ² each independently represent an atom selected from Group 16 elements of the periodic table.
One of R ¹ and R ² is the other is hydrogen atom in the alkyl group of 10-18 carbon atoms,
The other one of R ³ and R ⁴ an alkyl group of 10-18 carbon atoms represents a hydrogen atom,
D1 represents a repeating unit represented by the following formula (VI).

(In formula (VI), R ⁹ and R ¹⁰ are independent of hydrogen atom, halogen atom or monovalent atom.
Represents an organic group. )
In formula (II), Ar ³ represents a repeating unit represented by the following formula (XVI).

(X ⁷ represents a sulfur atom, and R ^{11 to} R ¹² are independent hydrogen atoms, halogen atoms or 1
Represents a valent organic group. )
And Ar ⁴ represent the repeating unit represented by the following formula (XVII).

(X ⁸ represents a sulfur atom, and R ^{13 to} R ¹⁴ independently represent a hydrogen atom, a halogen atom, or 1
Represents a valent organic group. )
c and d independently represent integers of 0 or more and 2 or less, respectively.
A is a structural unit represented by the following formula (VIII) or the following formula (IX).

(In formula (VIII), Ar ⁹ is an aromatic hydrocarbon ring that may have a substituent, a substituent.
It represents an aromatic heterocycle which may have or an aliphatic heterocycle which may have a substituent, and X ⁹ and X ¹⁰ are independently nitrogen atoms (N) or Q ⁴ (R ^15). ). In addition, Q ⁴ Zhou
Represents an atom selected from Group 14 elements in the timetable, where R ¹⁵ is a hydrogen atom, halogen atom or monovalent atom.
Represents an organic group. In formula (IX), Ar ¹⁰ is an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocycle which may have a substituent, or a fat which may have a substituent. It represents a group heterocycle, where X ¹¹ represents an atom selected from the Group 16 elements of the periodic table. )
D2 represents a repeating unit represented by the following formula (VI).

(In formula (VI), R ⁹ and R ¹⁰ are independent of hydrogen atom, halogen atom or monovalent atom.
Represents an organic group. ) ) In the formula (I), ^{R 1} and R ⁴ is an alkyl group of 10-18 carbon atoms independently, ^{R 2} and ^{R 3} are independently hydrogen atom, the copolymer of claim 1. In the formula (I), A is a repeating unit of the formula (X), a copolymer according to claim 1 or 2.

(In formula (X), R ¹⁶ and R ¹⁷ represent hydrogen atoms, halogen atoms or monovalent organic groups .) The copolymer according to any one of claims 1 to 3 , wherein the copolymer has a weight average molecular weight of 10,000 or more and 300,000 or less. A photoelectric conversion element having a pair of electrodes and an active layer between the pair of electrodes on a base material.
A photoelectric conversion element in which the active layer contains the copolymer according to any one of claims 1 to 4. A solar cell module having the photoelectric conversion element according to claim 5.

Images