JP6127789B2 - Copolymer, organic semiconductor material, organic electronic device and solar cell module - Google Patents

Description

  The present invention relates to copolymers, and organic semiconductor materials, organic electronic devices and solar cell modules containing the copolymers.

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

  Specifically, Non-Patent Document 1 describes a copolymer having an imidothiophene skeleton and a dithienocyclopentadiene skeleton, and a photoelectric conversion element using the copolymer. Non-Patent Documents 1, 2, 3 and Patent Document 1 describe a copolymer having an imidothiophene skeleton and a dithienosilole skeleton, and a photoelectric conversion element using the copolymer. Further, Non-Patent Document 2 describes a copolymer having an imidothiophene skeleton and a dithienogermol skeleton, and a photoelectric conversion element using the copolymer.

International Publication No. 2011/028827

J. et al. Mater. Chem. , 2011, 21, 3895-3902 J. et al. Am. Chem. Soc. , 2011, 133, 10062-10065 Chem. Commun. , 2011, 47, 4920-4922.

In order to fabricate an organic electronic device more easily, a solution in which an organic semiconductor material is dissolved (hereinafter sometimes referred to as ink) is produced, and the organic semiconductor material is formed by applying the ink. desirable. When used as a p-type semiconductor, a copolymer having a larger molecular weight is more effective for improving efficiency.
However, the inventors of the present application have investigated that an ink containing the above-described copolymer synthesized with a larger molecular weight and an organic solvent is gelled only by standing at room temperature for a few minutes. The problem of low storage stability was found. Moreover, when the said copolymer was used for the photoelectric conversion element, the photoelectric conversion efficiency obtained was inadequate.

  An object of the present invention is to provide a copolymer that can be used as a semiconductor material and has high stability when in solution. Moreover, it aims at providing the copolymer for manufacturing the photoelectric conversion element which has high conversion efficiency.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a repeating unit having a dithieno-fused ring skeleton and two or more kinds of repeating units having a dioxopyrrole-fused ring skeleton and different substituents from each other. The present copolymer was found to be highly stable when in solution despite having a larger molecular weight, and the present invention was completed based on this finding.

That is, the gist of the present invention is as follows.
[1] A copolymer comprising a repeating unit represented by the following formula (1A), a repeating unit represented by the formula (1B), and a repeating unit represented by the formula (1C).

(In Formula (1A), Formula (1B) and Formula (1C), A ¹ and A ² each independently represent an atom selected from Group 16 of the Periodic Table, and Q is selected from Group 14 of the Periodic Table) R ¹ represents a linear alkyl group that may have a substituent, R ² represents a branched alkyl group that may have a substituent, or a cycloalkyl that may have a substituent A group, an aromatic hydrocarbon group which may have a substituent, or a heterocyclic group which may have a substituent, each of R ³ and R ⁴ independently has a hetero atom; Represents a good hydrocarbon group.)
[2] The copolymer according to [1], comprising a repeating unit represented by the following formula (2A) and formula (2B).

(In Formula (2A) and Formula (2B), Q ¹ and Q ² each independently represent an atom selected from Group 14 of the periodic table, and A ¹ , A ² , R ^{1 to} R ⁴ represent the above formula ( The same meaning as in 1), R ⁵ and R ⁶ each independently represents a hydrocarbon group optionally having a hetero atom.
[3] An organic semiconductor material comprising the copolymer according to [1] or [2]. [4] An organic electronic device comprising the organic semiconductor material according to [3].
[5] The organic electronic device according to [4], which is a photoelectric conversion element.
[6] The organic electronic device according to [4], which is a solar cell.
[7] A solar cell module comprising the organic electronic device according to [6].

  A copolymer that can be used as a semiconductor material and has high stability when in solution can be provided. Moreover, the copolymer for manufacturing the photoelectric conversion element which has high conversion efficiency can be provided by using the copolymer which concerns on this invention.

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 requirements described below is an example (representative example) of an embodiment of the present invention, and the present invention is not specified in these contents unless it exceeds the gist.
<1. Copolymer according to the present invention>
The copolymer according to the present invention includes a repeating unit represented by the following formula (1A), a repeating unit represented by (1B) and a repeating unit represented by formula (1C). The copolymer according to the present invention is suitable for coating film formation because it is difficult to gel when dissolved. Further, the copolymer according to the present invention is preferable in that the light absorption wavelength region is at a longer wavelength, the light absorption is high, and the mobility is higher. In addition, the copolymer according to the present invention is preferable in that it can be easily obtained having a high molecular weight.

In Formula (1A) and Formula (1B), A ¹ and A ² each independently represent an atom selected from Group 16 of the periodic table. Specific examples of A ¹ and A ² include an oxygen atom, a sulfur atom, a selenium atom, and a tellurium atom. Among these, an oxygen atom, a sulfur atom or a selenium atom is preferred from the viewpoint of ease of synthesis, more preferably a sulfur atom or an oxygen atom, and particularly preferably a sulfur atom. A ¹ and A ² may be the same or different, preferably the same.

In formula (1C), Q represents an atom selected from Group 14 elements of the periodic table. Specific examples of atoms selected from Group 14 elements of the periodic table include carbon atoms, silicon atoms, germanium atoms, tin atoms, and lead atoms. Q is preferably a carbon atom, a silicon atom, a germanium atom and a tin atom, and more preferably a carbon atom, a silicon atom and a germanium atom. More preferably, they are a silicon atom or a germanium atom. Since silicon atoms and germanium atoms have a larger atomic radius than carbon atoms, steric hindrance due to substituents R ³ and R ⁴ that inhibit π-π stacking can be reduced. This is preferable in that the intermolecular interaction between the copolymers can be maintained moderately.

In formula (1A), R ¹ is a linear alkyl group which may have a substituent. This is preferable from the viewpoint of moderately strengthening the interaction between the polymers.
The carbon number of the linear alkyl group is usually 1 or more, preferably 3 or more, more preferably 4 or more, and usually 30 or less, preferably 20 or less, more preferably 16 or less, and still more preferably 12 or less. It is preferable from the point of solubility improvement that carbon number of a linear alkyl group is in the said range.

Examples of the linear alkyl group include a methyl group, an n-propyl group, an n-butyl group, an n-hexyl group, an n-octyl group, an n-decyl group, an n-dodecyl group, an n-tetradecyl group, and an n-hexadecyl group. Group, n-icosyl group, n-tetracosyl group, n-triacontyl group and the like.
Among these, n-butyl group, n-hexyl group, n-octyl group, n-decyl group, n-dodecyl group, n-tetradecyl group, n-hexadecyl group, n-icosyl group, n-tetracosyl group or an n-triacontyl group, and more preferably an n-butyl group and an n-hexyl group in that the charge transfer can be promoted by maintaining the solubility of the copolymer at a high level and by not separating the intermolecular distance of the copolymer too much. , N-octyl group, n-decyl group, or n-dodecyl group.
In Formula (1B), R ² represents a branched alkyl group that may have a substituent, a cycloalkyl group that may have a substituent, an aromatic hydrocarbon group that may have a substituent, or The heterocyclic group which may have a substituent is represented. It is considered that such a combination of R ¹ and R ² can suppress a decrease in solubility and gelation caused by regular alignment of polymer main chains, and can improve ink storage stability. It is done.
R ² is preferably a branched alkyl group which may have a substituent or an aromatic hydrocarbon group which may have a substituent, more preferably a substituent. A good branched alkyl group.

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

A branched primary alkyl group is preferable from the viewpoint of moderately strengthening intermolecular interaction and improving mobility, and a branched secondary alkyl group is preferable from the viewpoint of improving solubility.
The carbon number of the branched primary alkyl group is usually 3 or more, preferably 6 or more, more preferably 8 or more, and usually 30 or less, preferably 20 or less, more preferably 16 or less, and further preferably 12 or less. is there. It is preferable from the point of solubility improvement that the carbon number of the branched primary alkyl group is in the above range.

  Examples of the branched primary alkyl group include 2-ethylhexyl group, 2-methylpropyl group, 2,2-dimethylpropyl group, 2-ethylbutyl group, 2,4-dimethylhexyl group, 2-methylpentyl group, 2, 3-dimethylbutyl group, 2-hexyldecyl group, 2,2-dimethylbutyl group, 2-methylheptyl group, 2-butyloctyl group, 2-propylpentyl group, 2-methyloctyl group, 2-methyldodecyl group or Examples include 2,5-dimethylhexyl group.

  Among them, 2-ethylhexyl group, 2,4-dimethylhexyl group, 2,6-dimethylheptyl group, 2-hexyldecyl group, 2-methylheptyl group, 2-butyloctyl group, 2-propylpentyl group, 2 A methyl octyl group or a 2,5-dimethylhexyl group is preferable, and a 2-ethylhexyl group, a 2-hexyldecyl group, a 2-butyloctyl group or a 2-hexyloctyl group is more preferable.

The carbon number of the branched secondary alkyl group is usually 3 or more, preferably 4 or more, more preferably 5 or more, and usually 30 or less, preferably 20 or less, more preferably 16 or less, and still more preferably 12 or less. A branched secondary alkyl group having a carbon number within the above range is preferable in that the solubility can be improved.
Examples of the branched secondary alkyl group include 1-methylpropyl group, 1-methylheptyl group, 1-ethylhexyl group, 1-methylpentyl group, 1-methyloctyl group, 1-ethylbutyl group, 1-butylheptyl group, 4-methyl-1-propylhexyl group, 1,3-dimethylpentyl group, 1-ethyl-2-methylpentyl group, 1,2-dimethylpentyl group, 1-butylhexyl group, 1,3-dimethyldecyl group, Or 1-propyl heptyl group etc. are mentioned.

Among them, preferably 1-ethylhexyl group, 1-ethyl-2-methylpropyl group, 1-butylheptyl group, 1-ethyloctyl group, 1-propylhexyl group, 4-ethyl-1-methyloctyl group, 4- A methyl-1-propylhexyl group, a 1-ethyl-2-methylpentyl group, a 1-butylhexyl group or a 1-propylheptyl group;
The carbon number of the branched tertiary alkyl group is usually 4 or more, on the other hand, usually 30 or less, preferably 20 or less, more preferably 16 or less, and further preferably 12 or less.

  Examples of the branched tertiary alkyl group include t-butyl group, 2-ethyl-1,1-dimethylpentyl group, 1-ethyl-1,2-dimethylpropyl group, 1,1-dibutyldodecyl group, 1-butyl. -1-ethylhexyl group, 1-ethyl-1-propylpentyl group, 1,1-dimethylheptyl group, 1,1-dimethyldecyl group, 1,1-dimethylpentyl group, 1,1-dibutylpentyl group, 1- Examples thereof include a butyl-1-propylpentyl group, 1-hexyl-1-methylnonyl group, 1-ethyl-1-methylpropyl group, 1,1,2,2-tetramethylpropyl group, and the like.

Of these, a t-butyl group or a 1,1-dimethylpropyl group is preferable, and a t-butyl group is more preferable.
The carbon number of the cycloalkyl group is usually 3 or more, more preferably 4 or more, and usually 30 or less, preferably 20 or less, more preferably 16 or less, and still more preferably 12 or less.
Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, and a cyclolauryl group. Of these, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group or a cyclooctyl group is preferable.

The aromatic hydrocarbon group has usually 6 or more carbon atoms, usually 30 or less, preferably 20 or less, more preferably 14 or less. Examples of such an aromatic hydrocarbon group include a phenyl group, a naphthyl group, an indanyl group, an indenyl group, a fluorenyl group, an anthracenyl group, and an azulenyl group. Of these, a phenyl group or a naphthyl group is preferable.
Examples of the heterocyclic group include an aliphatic heterocyclic group and an aromatic heterocyclic group. The carbon number of the aliphatic heterocyclic group is usually 2 or more, on the other hand, usually 20 or less, preferably 14 or less, more preferably 12 or less, still more preferably 10 or less, and particularly preferably 6 or less. Examples of such an aliphatic heterocyclic group include an oxetanyl group, a pyrrolidinyl group, a tetrahydrofuryl group, a tetrahydrothienyl group, a piperidinyl group, a tetrahydropyranyl group, and a tetrahydrothiopyranyl group.

The carbon number of the aromatic heterocyclic group is usually 2 or more, on the other hand, usually 30 or less, preferably 20 or less, more preferably 14 or less. Examples of such aromatic heterocyclic groups include thienyl, furanyl, pyridyl, pyrimidyl, thiazolyl, oxazolyl, triazolyl, benzothiophenyl, benzofuranyl, benzothiazolyl, and benzoxazolyl groups. Or a benzotriazolyl group etc. are mentioned. Of these, a thienyl group, a pyridyl group, a pyrimidyl group, a thiazolyl group, or an oxazolyl group is preferable. The substituent that R ¹ and R ² may “have” is not particularly limited as long as the effects of the present invention are not impaired, but preferably a halogen atom, a hydroxyl group, a carboxyl group, a carbamoyl group, an acyl group, Alkoxycarbonyl group, aryloxycarbonyl group, alkylsulfonyl group, arylsulfonyl group, boryl group, alkyl group, alkenyl group, alkynyl group, alkoxy group, aryloxy group, alkylthio group, arylthio group, amino group, substituted amino group, silyl Group, substituted silyl group, aliphatic heterocyclic group, aromatic hydrocarbon group or aromatic heterocyclic group. Among these, a halogen atom, an alkoxy group, or an alkylthio group is preferable because the intramolecular polarity of the copolymer according to the present invention can be controlled.

R ³ and R ⁴ each independently represents a hydrocarbon group which may have a hetero atom. Specifically, a linear alkyl group that may have a substituent, a branched alkyl group that may have a substituent, a cycloalkyl group that may have a substituent, and a substituent An aromatic hydrocarbon group that may be present, and a heterocyclic group that may have a substituent, are the same as those defined for R ¹ and R ² . R ³ and R ⁴ may be the same or different.

Among them, preferably, at least one of R ³ and R ⁴ may have an alkyl group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, or a substituent. Good aromatic heterocyclic group.
From the viewpoint of improving the solubility, both R ³ and R ⁴ are more preferably an alkyl group which may have a substituent, and more preferably a branched alkyl group which may have a substituent, Particularly preferred is a branched primary alkyl optionally having a substituent.

Further, alternatively, Q is a chiral atom, the resulting copolymer is, since it is possible to have a number of diastereomers, because it can improve the solubility, is R ^3, a substituent More preferably a linear alkyl group that may be substituted, and a branched alkyl group in which R ⁴ may have a substituent, and particularly preferably a linear alkyl group in which R ³ may have a substituent, R ⁴ is a branched primary alkyl group which may have a substituent.

The substituent that R ³ and R ⁴ may have have the same meaning as the substituent that R ¹ and R ² may have. Among them, a substituent consisting of an atom selected from the group containing a hydrogen atom and a hetero atom is preferable, and more preferably a halogen atom such as a fluorine atom in terms of increasing polarity, or an aminocarbonyl in terms of having hydrogen bonding ability. Or a group having an amide bond such as a carbonylamino group.

Moreover, it is also preferable that at least one of R ³ and R ^{4 is} a branched alkyl group having no substituent. Particularly preferred are 2-ethylhexyl group, 2-ethylheptyl group, 2-ethyloctyl group, 2-ethylnonyl group, 2-ethyldecanyl group and the like.
It is preferable that at least one of R ³ and R ⁴ contains a branched alkyl group, and that both of them are branched alkyl groups from the viewpoint of increasing solubility.

In the formula (1A) and the formula (1B), when the substituents of R ¹ and R ² are different, the distance between the polymers can be made non-uniform, so that the solubility of the copolymer is improved.
This is preferable in that the solubility of the copolymer according to the present invention in an organic solvent is likely to be improved, and the copolymer according to the present invention can be easily formed by coating. Further, it is also preferable in that storage stability can be improved by suppressing the precipitation or gelation of the copolymer when the copolymer according to the present invention is used as a solution.

  The repeating unit having a linear alkyl group on the dioxopyrrole condensed ring and the repeating unit having a branched alkyl group on the dioxopyrrole condensed ring have a spatial extension with the repeating unit having a linear substituent, respectively. It is considered to be a repeating unit having a substituent having. Therefore, a portion where the intermolecular distance between the copolymers according to the present invention having the above repeating unit can be appropriately separated and a portion close to each other can coexist, and an irregular distance can be provided between the copolymers. We think that we can plan improvement of.

In addition, since the copolymer of the present invention has a repeating unit having a linear substituent and a repeating unit having a spatial extension, a dithieno condensed ring and a dioxopyrrole condensed between a plurality of copolymers. The intermolecular interaction between the rings and / or between the dithieno-fused rings is appropriately adjusted. Therefore, although it is a high molecular weight substance, at the same time, the solubility is improved and the copolymer is suppressed from aggregation, crystallization or gelation, and as a result, the stability of the ink containing the copolymer can be improved. Think.

The copolymer according to the present invention includes two or more of each of one or more of the repeating unit represented by the formula (1A), the repeating unit represented by the formula (1B), and the repeating unit represented by the formula (1C). The above may be included.
The copolymer according to the present invention may contain a repeating unit other than the repeating unit represented by the formula (1A), (1B) or (1C) as long as the effects of the present invention are not impaired. The proportion of the repeating unit represented by the formula (1A), the repeating unit represented by the formula (1B), and the repeating unit represented by the formula (1C) in the repeating unit constituting the copolymer according to the present invention. Is not particularly limited, but is usually 2 mol% or more, preferably 10 mol% or more, more preferably 25 mol% or more, more preferably 50 mol% or more, still more preferably 70 mol% or more, still more preferably 90% or more. Particularly preferably, the copolymer according to the present invention comprises a repeating unit represented by the formula (1A), a repeating unit represented by the formula (1B), and a repeating unit represented by the formula (1C) and these repeating units. It is composed only of units, or includes a polymer chain that includes these repeating units and is composed only of these repeating units.

The proportion of the repeating unit represented by the formula (1A) in the repeating unit constituting the copolymer according to the present invention is not particularly limited, but is usually 1 mol% or more, preferably 2 mol% or more, more preferably It is 10 mol% or more, more preferably 30 mol% or more. On the other hand, it is usually 99 mol% or less, preferably 90 mol% or less, more preferably 70 mol% or less.
The proportion of the repeating unit represented by the formula (1B) in the repeating unit constituting the copolymer according to the present invention is not particularly limited, but is usually 1 mol% or more, preferably 10 mol% or more, more preferably It is 30 mol% or more. On the other hand, it is usually 99 mol% or less, preferably 90 mol% or less, more preferably 70 mol% or less.

The proportion of the repeating unit represented by the formula (1C) in the repeating unit constituting the copolymer according to the present invention is not particularly limited, but is usually 1 mol% or more, preferably 2 mol% or more, more preferably It is 10 mol% or more, more preferably 30 mol% or more. On the other hand, it is usually 99 mol% or less, preferably 90 mol% or less, more preferably 70 mol% or less.
In the copolymer according to the present invention, the number ratio of repeating units represented by formula (1C) to the number of repeating units represented by formula (1A) + formula (1B) (1C / 1A + 1B) is Although there is no restriction | limiting, Usually, 0.01 or more, Preferably it is 0.1 or more, More preferably, it is 0.5 or more. On the other hand, it is usually 100 or less, preferably 10 or less, more preferably 2 or less.

  In the copolymer according to the present invention, the arrangement state of the repeating units represented by formula (1A), formula (1B) and formula (1C) may be either block or random. That is, the copolymer according to the present invention may be either a block copolymer or a random copolymer. In addition, a copolymer having an intermediate structure among these copolymers, for example, a random copolymer having a block property may be used. Also included are copolymers and dendrimers that are branched in the main chain and have three or more terminal portions. Among them, a block copolymer or a random copolymer is preferable because synthesis is easy and regularity can be further lowered, and the solubility of the copolymer is improved and the storage stability of the ink in which the copolymer is dissolved is more improved. In view of improvement, a random copolymer is more preferable.

Especially, it is preferable that the copolymer which concerns on this invention has a repeating unit represented by following formula (2A) and formula (2B). A copolymer having repeating units represented by the following formulas (2A) and (2B) is preferable in that the charge separation state can be more easily maintained.

In formula (2A) and formula (2B), A ¹ , A ² , and R ^{1 to} R ⁴ have the same meanings as described above.
In formula (2A) and formula (2B), Q ¹ and Q ² each independently represents an atom selected from Group 14 elements of the periodic table. Q ¹ and ^{Q 2} are the same as ^{Q 1} and ^{Q 2} in the formula (1B) and (1C).
R ⁵ and R ⁶ each independently represent a hydrocarbon group that may have a hetero atom, and have the same meanings as R ³ and R ⁴ .

The copolymer according to the present invention may contain two or more of each one or more of the repeating units represented by the formula (2A) and (2B).
The copolymer according to the present invention may contain a repeating unit other than the repeating unit represented by the formula (2A) or (2B) as long as the effects of the present invention are not impaired. The total proportion of the repeating unit represented by the formula (2A) and the repeating unit represented by the formula (2B) in the repeating units constituting the copolymer according to the present invention is not particularly limited, but is usually 2 mol%. More preferably, it is 10 mol% or more, more preferably 25 mol% or more, more preferably 50 mol% or more, still more preferably 70 mol% or more, and still more preferably 90% or more. Particularly preferably, the copolymer according to the present invention comprises a repeating unit represented by the formula (2A) and a repeating unit represented by the formula (2B) and is composed only of these repeating units, or these repeating units. A polymer chain containing units and composed only of these repeating units is included.

The proportion of the repeating unit represented by the formula (2A) in the repeating unit constituting the copolymer according to the present invention is not particularly limited, but is usually 1 mol% or more, preferably 10 mol% or more, more preferably It is 20 mol% or more. On the other hand, it is usually 99 mol% or less, preferably 90 mol% or less, more preferably 70 mol% or less.
The proportion of the repeating unit represented by the formula (2B) in the repeating unit constituting the copolymer according to the present invention is not particularly limited, but is usually 1 mol% or more, preferably 10 mol% or more, more preferably It is 20 mol% or more. On the other hand, it is usually 99 mol% or less, preferably 90 mol% or less, more preferably 70 mol% or less.

The number ratio (2A / 2B) of the number of repeating units represented by the formula (2A) to the number of repeating units represented by the formula (2B) in the copolymer according to the present invention is not particularly limited. 0.01 or more, preferably 0.1 or more, more preferably 0.2 or more. On the other hand, it is usually 100 or less, preferably 10 or less, more preferably 5 or less.
In the copolymer according to the present invention, the arrangement state of the repeating units represented by the formula (2A) and the formula (2B) may be alternating, block or random. That is, the copolymer according to the present invention may be an alternating copolymer, a block copolymer, or a random copolymer. In addition, a copolymer having an intermediate structure among these copolymers, for example, a random copolymer having a block property may be used. Also included are copolymers and dendrimers that are branched in the main chain and have three or more terminal portions. Among these, a block copolymer or a random copolymer is preferable because it is easy to synthesize and regularity can be lowered, and the solubility of the copolymer is improved and the storage stability of the ink in which the copolymer is dissolved is improved. In view of this, a random copolymer is more preferable.

  Preferred specific examples of the copolymer according to the present invention are shown below. However, the copolymer according to the present invention is not limited to the following examples. In the following examples, m and n represent mole fractions, and are positive numbers such that m + n = 1.

The polystyrene-converted weight average molecular weight (Mw) of the copolymer according to the present invention is usually 2.0 × 10 ⁴ or more, preferably 3.0 × 10 ⁴ or more, more preferably 4.0 × 10 ⁴ or more, and still more preferably. It is 5.0 × 10 ⁴ or more, more preferably 7.0 × 10 ⁴ or more, and particularly preferably 1.0 × 10 ⁵ or more. On the other hand, it is preferably 1.0 × 10 ⁷ or less, more preferably 1.0 × 10 ⁶ or less, and particularly preferably 5.0 × 10 ⁵ or less. The weight average molecular weight is preferably in this range from the viewpoint of increasing the light absorption wavelength, from the viewpoint of realizing high absorbance, from the viewpoint of realizing high carrier movement, and from the viewpoint of solubility in an organic solvent.

The polystyrene-reduced number average molecular weight (Mn) of the copolymer according to the present invention is usually 5.0 × 10 ³ or more, preferably 1.0 × 10 ⁴ or more, more preferably 2.0 × 10 ⁴ or more, and still more preferably. It is 2.5 × 10 ⁴ or more, particularly preferably 3.0 × 10 ⁴ or more. On the other hand, it is preferably 1.0 × 10 ⁷ or less, more preferably 1.0 × 10 ⁶ or less, further preferably 5.0 × 10 ⁵ or less, even more preferably 2.0 × 10 ⁵ or less, and particularly preferably 1 0.0 × 10 ⁵ or less. The number average molecular weight is preferably in this range from the viewpoint of increasing the light absorption wavelength, from the viewpoint of realizing high absorbance, from the viewpoint of realizing high carrier movement, and from the viewpoint of solubility in an organic solvent.

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

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

The copolymer according to the present invention preferably has a light absorption maximum wavelength (λ _max ) of usually 470 nm or more, preferably 480 nm or more, while usually 1200 nm or less, preferably 1000 nm or less, more preferably 900 nm or less. Further, the full width at half maximum of the absorption maximum wavelength on the longest wavelength side in the range of 350 nm to 850 nm is usually 10 nm or more, preferably 20 nm or more, and usually 300 nm or less. Moreover, when using the copolymer which concerns on this invention for a solar cell use, it is so desirable that the absorption wavelength range of a copolymer is near the wavelength range of sunlight.

The solubility of the copolymer according to the present invention is not particularly limited, but preferably the solubility in chlorobenzene at 25 ° C. is usually 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 1% by mass or more. On the other hand, it is usually 30% by mass or less, preferably 20% by mass. High solubility is preferable because a thicker film can be formed by coating.
The copolymer according to the present invention preferably has an appropriate interaction between molecules. In the present specification, the interaction between molecules means that the distance between polymer chains is shortened by an interaction such as π-π stacking between molecules. The stronger the interaction, the higher the mobility and / or crystallinity, and the more suitable the semiconductor material is. That is, in a copolymer that interacts between molecules, electron transfer between molecules is likely to occur. For example, when the copolymer according to the present invention is used in an active layer in a photoelectric conversion element, a p-type semiconductor compound in the active layer is used. It is considered that holes generated at the interface between the n-type semiconductor compound and the n-type semiconductor compound can be efficiently transported to the electrode (anode).

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

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

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

  The impurities in the copolymer according to the present invention are preferably as few as possible. In particular, when a transition metal catalyst such as palladium or copper remains, exciton trapping occurs due to the heavy atom effect of the transition metal, which inhibits charge transfer. As a result, the copolymer according to the present invention was used in a photoelectric conversion element. In some cases, the photoelectric conversion efficiency may be reduced. The concentration of the transition metal catalyst is usually 1000 ppm or less, preferably 500 pm or less, more preferably 100 ppm or less, per 1 g of 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.

  In the copolymer according to the present invention, the residual amount of atoms constituting the terminal residue (for example, X and Y in the formulas (3A) to (3C) described later) is not particularly limited, but usually per 1 g of the copolymer. It is 6000 ppm or less, preferably 4000 ppm or less, more preferably 3000 ppm or less, further preferably 2000 ppm or less, still more preferably 1000 ppm or less, particularly preferably 500 ppm or less, and most preferably 200 ppm or less. On the other hand, it is usually greater than 0 ppm, preferably 1 ppm or more, more preferably 3 ppm or more.

In particular, the residual amount of Sn atoms in the copolymer according to the present invention is usually 5000 ppm or less, preferably 4000 ppm or less, more preferably 2500 ppm or less, further preferably 1000 ppm or less, even more preferably 750 ppm or less, especially 1 g of copolymer. Preferably it is 500 ppm or less, and most preferably 100 ppm or less. On the other hand, it is usually greater than 0 ppm, preferably 1 ppm or more, more preferably 3 ppm or more. The remaining amount of Sn atoms of 5000 ppm or less is preferable because it means that there are few alkylstannyl groups and the like that are easily thermally decomposed, and high performance can be obtained in terms of stability.

  Further, the residual amount of halogen atoms in the copolymer according to the present invention is usually 5000 ppm or less, preferably 4000 ppm or less, more preferably 2500 ppm or less, further preferably 1000 ppm or less, even more preferably 750 ppm or less, and particularly preferably, per 1 g of the copolymer. Is 500 ppm or less, most preferably 100 ppm or less. On the other hand, it is usually greater than 0 ppm, preferably 1 ppm or more, more preferably 3 ppm or more. It is preferable to set the residual amount of halogen atoms to 5000 ppm or less because performances such as the photoelectric conversion characteristics and durability of the copolymer tend to be improved.

The residual amount of atoms constituting the terminal residue (for example, X and Y in formulas (3A) to (3C) described later) in the copolymer can be determined by measuring the element amount. The elemental analysis of the copolymer can be carried out by ICP mass spectrometry for Pd and Sn, for example, and can also be carried out by ICP mass spectrometry for bromine ions (Br ⁻ ) and iodine ions (I ⁻ ).

ICP mass spectrometry can be carried out by a method described in a known document (“Plasma ion source mass spectrometry” (Academic Publishing Center)). Specifically, for Pd and Sn, after wet decomposition of the sample, Pd and Sn in the decomposition solution are quantified by a calibration curve method using an ICP mass spectrometer (ICP mass spectrometer 7500ce type manufactured by Agilent Technologies). be able to. For Br ⁻ and I ⁻ , the sample was burned with a sample combustion device (sample combustion device QF-02 type manufactured by Mitsubishi Chemical Analytech Co., Ltd.), and the combustion gas was absorbed into an alkaline absorbent containing a reducing agent. Br ⁻ and I ⁻ in the absorbing solution can be quantified by a calibration curve method using an ICP mass spectrometer (ICP mass spectrometer 7500ce type manufactured by Agilent Technologies).

<2. Method for producing copolymer according to the present invention>
The method for producing the copolymer according to the present invention is not particularly limited. For example, the copolymer can be produced by a known method using a compound having a dioxopyrrole condensed ring and a compound having a dithieno condensed ring. As a preferable method, a compound represented by the following general formula (3A), a compound represented by the following general formula (3B), and a compound represented by the following general formula (3C) are suitably used if necessary. And polymerization in the presence of a catalyst.

In formula (3A), R ¹ and A ¹ have the same meaning as defined in formula (1A), and
In B), R ² and A ² have the same meaning as defined in formula (1B). In formula (3C), R ³ , R ⁴ and Q have the same meanings as defined in formula (1C).
In formulas (3A) to (3C), X and Y can be appropriately selected according to the type of polymerization reaction. For example, the copolymer according to the present invention can be produced by a polymerization reaction using a coupling reaction. Usable reactions include a Suzuki-Miyaura cross-coupling reaction method, a Stille coupling reaction method, a Yamamoto coupling reaction method, a Grignard reaction method, a Heck reaction method, a Sonogashira reaction method, and a reaction using an oxidizing agent such as FeCl _3. And a method using an electrochemical oxidation reaction, a reaction method by decomposition of an intermediate compound having an appropriate leaving group, and the like. Among these, the Suzuki-Miyaura coupling reaction method, the Stille coupling reaction method, the Yamamoto coupling reaction method, and the Grignard reaction method are preferable in terms of easy structure control. In particular, the Suzuki-Miyaura cross-coupling reaction method, the Stille coupling reaction method, and the Grignard reaction method are preferable from the viewpoint of easy availability of materials and easy reaction operation. These reactions are described in "Cross Coupling-Fundamentals and Industrial Applications (CMC Publishing)", "Transition Metal Catalyzed Reactions for Organic Synthesis (edited by Jiro Jiro: edited by Organic Synthetic Chemical Society)", "For Organic Synthesis" The reaction can be carried out according to a method described in known literature such as “catalytic reaction 103 (Teijiro Hatakeyama: Tokyo Kagaku Dojin)”.

Examples of X and Y are each independently a halogen atom, alkylstannyl group, alkylsulfo group, arylsulfo group, arylalkylsulfo group, boric acid ester residue, sulfoniummethyl group, phosphoniummethyl group, phosphonatemethyl Group, monohalogenated methyl group, boric acid residue (-B (OH) ₂ ), formyl group, silyl group, alkenyl group or alkynyl group.

As the halogen atom, a bromine atom or an iodine atom is preferable. Examples of the alkenyl group include alkenyl groups having 2 to 12 carbon atoms.
Examples of the boric acid ester residue include those represented by the following formula. In the following formulae, Me represents a methyl group, and Et represents an ethyl group.

  Examples of the alkylstannyl group include those represented by the following formula. In the following formulae, Me represents a methyl group, and Bu represents an n-butyl group.

From the viewpoints of synthesis of compounds represented by formulas (3A) to (3C) and ease of reaction, one of X and Y is a halogen atom, and the other is an alkylstannyl group or borate ester. It is preferably a residue or a boric acid residue (—B (OH) ₂ ).
The polymerization reaction can be performed according to a known method. For example, when X or Y is an alkylstannyl group, the reaction may be performed in accordance with known Stille coupling reaction conditions. In addition, when X or Y is a boric acid ester residue or a boric acid residue, the reaction may be performed according to the conditions of a known Suzuki-Miyaura coupling reaction. Furthermore, when X or Y is a silyl group, the reaction may be carried out in accordance with known Hiyama coupling reaction conditions. As a catalyst for the coupling reaction, for example, a combination of a transition metal such as palladium and a ligand (for example, a phosphine ligand such as triphenylphosphine) can be used.

Hereinafter, a method for producing the copolymer according to the present invention using the Stille coupling reaction method will be described. When the Stille coupling reaction method is used, in the formulas (3A) to (3C), X is a halogen atom and Y is an alkylstannyl group, or X is an alkylstannyl group and Y is a halogen atom. Preferably there is.
The ratio ((3A + 3B) / 3C) of the sum of the amount of the compound represented by the formula (3C) to the amount of the compound represented by the formula (3A) and the formula (3B) used in the polymerization reaction is mol In terms of ratio, it is usually 0.90 or more, preferably 0.95 or more, and is usually 1.3 or less, preferably 1.2 or less. It is preferable that the ratio is in such a range in that a high molecular weight product can be obtained with a higher yield.

  The ratio (3A / 3B) of the amount of the compound represented by the formula (3B) to the amount of the compound represented by the formula (3A) used in the polymerization reaction is appropriately set depending on the purpose without any particular limitation. However, in terms of molar ratio, it is usually 0.01 or more, preferably 0.1 or more, more preferably 0.5 or more. On the other hand, it is usually 100 or less, preferably 10 or less, more preferably 2 or less.

When it is desirable that the copolymer according to the present invention has a high purity, it is preferable to carry out the polymerization reaction after purifying the monomer before polymerization (compounds represented by formulas (3A) to (3C)). Examples of the purification method include distillation, sublimation purification, column chromatography, recrystallization, and the like.
For example, when the copolymer according to the present invention is used as a material for an organic photoelectric conversion device, it is desirable that the copolymer has a high purity since the device characteristics can be improved due to its high purity. When the copolymer according to the present invention is used as a material for an organic photoelectric conversion element, the purity of each of the compounds represented by formulas (3A) to (3C) is usually 90% or more, preferably 95% or more.

Examples of the catalyst used for the promotion of polymerization in the polymerization reaction include transition metal catalysts. What is necessary is just to select a transition metal catalyst according to the kind of superposition | polymerization. Examples of transition metal catalysts include homogeneous transition metal catalysts and heterogeneous transition metal catalysts.
The homogeneous transition metal catalyst is preferably one that is sufficiently soluble in the solvent used for the polymerization reaction. Preferred examples include late transition metal complex catalysts containing palladium, nickel, iron, or copper, among others. Specific examples include zero-valent palladium catalysts such as tetrakis (triphenylphosphine) palladium (Pd (PPh ₃ ) ₄ ) or tris (dibenzylideneacetone) dipalladium (Pd ₂ (dba) ₃ ); bis (tri Palladium (Pd) catalysts such as phenylphosphine) palladium chloride (PdCl ₂ ((PPh ₃ )) ₂ ) or divalent palladium catalysts such as palladium acetate; nickel such as Ni (dppp) Cl ₂ or Ni (dppe) Cl ₂ Catalysts: iron catalysts such as iron chloride; copper catalysts such as copper iodide. Here, dba represents dibenzylideneacetone, dppp represents 1,2-bis (diphenylphosphino) propane, and dppe represents 1,2-bis (diphenylphosphino) ethane.

Specific examples of the zero-valent Pd catalyst include Pd (PPh ₃ ) ₄ , Pd (P (o-tolyl)
_{3) 4, Pd (PCy 3} ) 2, Pd 2 (dba) 3, PdCl 2 (PPh 3)) 2 and the like. When a divalent Pd catalyst such as PdCl ₂ ((PPh ₃ )) ₂ or palladium acetate is used, it is preferably used in combination with an organic ligand such as PPh ₃ or P (o-tolyl) ₃ . Here, Ph represents a phenyl group, Cy represents a cyclohexyl group, and o-tolyl represents a 2-tolyl group.

  Examples of the heterogeneous transition metal catalyst include a catalyst obtained by supporting a homogeneous transition metal catalyst as described above on a carrier. Preferable examples of the transition metal included in the heterogeneous transition metal catalyst include late transition metals including palladium, nickel, iron, or copper. As an organic ligand which a heterogeneous transition metal complex catalyst has, the same thing as what was mentioned about the homogeneous transition metal complex catalyst can be used. In addition, organic ligands described in known literature (Strem, “Heterogeneous Catalysts” (2011)) can also be used. Examples of the carrier include metals, nanocolloids, nanoparticles, magnetic compounds, metal oxides, porous materials, clays, polymers such as urea resins, and dendrimers. Specific examples of the porous material include microporous material, mesoporous material, activated carbon, silica gel, alumina, and zeolite. In particular, it is preferable to use a heterogeneous transition metal complex catalyst supported on a polymer because the heterogeneous transition metal complex catalyst can be easily recovered. Moreover, it is more preferable that the polymer is porous in terms of promoting the reaction.

  In the polymerization reaction, it is preferable to use two or more transition metal complex catalysts in that a high molecular weight copolymer can be obtained. For example, two or more kinds of homogeneous transition metal complexes may be used, two or more kinds of heterogeneous transition metal complexes may be used, or a combination of a homogeneous transition metal complex and a heterogeneous transition metal complex may be used. May be used. Of these two or more transition metal complex catalysts, at least one of them is preferably a heterogeneous metal complex catalyst in that a monomer can be quickly converted into an oligomer under coupling reaction conditions. In addition, since oligomerization tends to decrease the polymerization reaction rate due to the heterogeneous metal catalyst, it is preferable to induce the oligomer to the polymer with the homogeneous metal catalyst in order to obtain a high molecular weight product. From this viewpoint, it is more preferable that at least one of the two or more transition metal complex catalysts is a heterogeneous metal complex catalyst and at least one is a homogeneous metal complex catalyst.

The addition rate of the transition metal complex with respect to the total amount of the compounds represented by formulas (3A) to (3C) is usually 1 × 10 ⁻⁴ mol% or more, preferably 1 × 10 ⁻³ mol% or more, more preferably and a 1 × ¹⁰ -2 mol% or more, whereas, usually 1 × ¹⁰ 2 mol%, more preferably at most 5 mol%. It is preferable that the addition ratio of the catalyst is within this range because a copolymer having a higher molecular weight tends to be obtained at a lower cost and a higher yield.
When using a transition metal catalyst, an alkali, a cocatalyst or a phase transfer catalyst may be used in combination.

Examples of the alkali include inorganic bases such as potassium carbonate, sodium carbonate and cesium carbonate; organic bases such as triethylamine.
Examples of the cocatalyst include inorganic salts such as cesium fluoride, copper oxide, and copper halide. The addition rate of the cocatalyst is usually 1 × 10 ⁻⁴ mol% or more, preferably 1 × 10 ⁻³ mol% or more, based on the total amount of the compounds represented by formulas (3A) to (3C). Preferably, it is 1 × 10 ⁻² mol% or more, and is usually 1 × 10 ⁴ mol% or less, preferably 1 × 10 ³ mol% or less, more preferably 1.5 × 10 ² mol% or less. It is preferable that the addition rate of the cocatalyst is within this range because the copolymer tends to be obtained at a lower cost and with a higher yield.

Phase transfer catalysts include tetraethylammonium hydroxide or Aliquat 3
And quaternary ammonium salts such as 36 (manufactured by Aldrich). The addition rate of the phase transfer catalyst is usually 1 × 10 ⁻⁴ mol% or more, preferably 1 × 10 ⁻³ mol% or more, based on the total amount of the compounds represented by formulas (3A) to (3C), More preferably, it is 1 × 10 ⁻² mol% or more, while it is usually 5 mol% or less, more preferably 3 mol% or less. The addition rate of the phase transfer catalyst within this range is preferable because the copolymer tends to be obtained at a lower cost and with a higher yield.

  Examples of the solvent used in the polymerization reaction include saturated hydrocarbons such as pentane, hexane, heptane, octane, and cyclohexane; aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene; halogens such as chlorobenzene, dichlorobenzene, and trichlorobenzene. Aromatic hydrocarbons; alcohols such as methanol, ethanol, propanol, isopropanol, butanol or t-butyl alcohol; water; ethers such as dimethyl ether, diethyl ether, methyl t-butyl ether, tetrahydrofuran, tetrahydropyran or dioxane; DMF And aprotic polar organic solvents such as These solvents may be used alone or in combination of two or more.

The addition rate of the solvent is usually 1 × 10 ⁻² mL or more, preferably 1 × 10 ⁻¹ mL or more, more preferably ¹ mL with respect to 1 g of the total of the compounds represented by formulas (3A) to (3C). On the other hand, it is usually 1 × 10 ⁵ mL or less, preferably 1 × 10 ³ mL or less, more preferably 2 × 10 ² mL or less. It is preferable that the addition rate of the solvent is within this range because the control of the reaction becomes easier.

The reaction temperature of the polymerization reaction is usually 0 ° C. or higher, preferably 20 ° C. or higher, more preferably 40 ° C. or higher, and further preferably 60 ° C. or higher. On the other hand, it is usually 300 ° C. or lower, preferably 250 ° C. or lower, more preferably 200 ° C. or lower, further preferably 180 ° C. or lower, and particularly preferably 160 ° C. or lower. The heating method is not particularly limited, but examples include oil bath heating, thermocouple heating, infrared heating, microwave heating, heating by contact using an IH heater, and the like. The time for the polymerization reaction is usually 1 minute or more, preferably 10 minutes or more, while it is usually 160 hours or less, preferably 120 hours or less, more preferably 100 hours or less. The polymerization reaction is preferably performed in a nitrogen (N ₂ ) or argon (Ar) atmosphere. By carrying out the reaction under these reaction conditions, the copolymer can be obtained in a shorter time and with a higher yield.

  It is preferable to further end-treat the copolymer obtained by the polymerization reaction. By performing the terminal treatment of the copolymer, the residual amount of the terminal residues (X and Y described above) can be reduced. For example, when a copolymer is polymerized by a Stille coupling reaction, halogen atoms such as bromine (Br) and iodine (I) and alkylstannyl groups present at the terminal of the copolymer can be reduced by terminal treatment. This terminal treatment is preferable because a copolymer having better performance in terms of efficiency and durability can be obtained.

The terminal treatment method of the copolymer after the polymerization reaction is not particularly limited, and examples thereof include a method of substituting the terminal residue with another substituent such as an aromatic group.
For example, as a terminal treatment method when a copolymer is polymerized by a Stille coupling reaction, the following method may be mentioned. The method for terminal treatment of the halogen atom of the copolymer can be carried out by adding aryltrialkyltin as a terminal treatment agent to the reaction system after the polymerization reaction and before purification, followed by heating and stirring. Examples of aryltrialkyltin include phenyltrimethyltin or thienyltrimethyltin. Substitution of a halogen atom at the terminal of the copolymer with an aromatic group is preferable because the copolymer becomes more stable due to the conjugate stability effect.

The addition amount of the end treatment agent is not particularly limited, but is usually 1.0 × 10 ^{−2 with} respect to the amount of the monomer having a halogen atom at the end (3A and 3B, or 3C) used in the polymerization reaction. The molar equivalent or higher, preferably 0.1 molar equivalent or higher, more preferably 1 molar equivalent or higher, and usually 50 molar equivalents or lower, preferably 20 molar equivalents or lower, more preferably 10 molar equivalents or lower. The reaction temperature of the halogen atom terminal treatment is usually 0 ° C. or higher, preferably 20 ° C. or higher, more preferably 40 ° C. or higher, and further preferably 60 ° C. or higher. On the other hand, it is usually 300 ° C. or lower, preferably 250 ° C. or lower, more preferably 200 ° C. or lower, further preferably 180 ° C. or lower, and particularly preferably 160 ° C. or lower. The heating method is not particularly limited, and examples thereof include oil bath heating, thermocouple heating, infrared heating, microwave heating, heating by contact using an IH heater, and the like. The reaction time of the terminal treatment of the halogen atom of the copolymer is not particularly limited, but is usually 30 minutes or longer, preferably 1 hour or longer, and is usually 50 hours or shorter, preferably 20 hours or shorter. By performing the reaction under these reaction conditions, the terminal treatment can be performed in a shorter time and with a higher conversion rate.

  Further, the terminal treatment method of the alkylstannyl group of the copolymer can be carried out by adding an aryl halide as a terminal treating agent in the reaction system after the polymerization reaction and before purification, followed by heating and stirring. Examples of aryl halides include iodothiophene, iodobenzene, bromothiophene or bromobenzene. By substituting the alkylstannyl group at the terminal of the copolymer with another substituent, the Sn atom in the alkylstannyl group which is easily thermally decomposed does not exist in the copolymer, and deterioration of the copolymer over time can be suppressed. Further, substitution of the alkylstannyl group at the terminal of the copolymer with an aryl group is also preferable in that the copolymer can be more stable due to the conjugate stability effect.

The addition amount of the end treatment agent is not particularly limited, but is usually 1.0 × 10 ^{− with} respect to the amount of the monomer (3A and 3B, or 3C) having an alkylstannyl group used for polymerization. ^{It is 2} molar equivalents or more, preferably 0.1 molar equivalents or more, more preferably 1 molar equivalents or more, and is usually 50 molar equivalents or less, preferably 20 molar equivalents or less, more preferably 10 molar equivalents or less. As the reaction temperature and reaction conditions for the terminal treatment of the alkylstannyl group, those similar to the terminal treatment of the halogen atom of the copolymer can be used. By performing the reaction under these reaction conditions, the terminal treatment can be performed in a shorter time and with a higher conversion rate.

  Moreover, the following method is mentioned as a method of terminal treatment at the time of polymerizing a copolymer by Suzuki-Miyaura cross-coupling reaction. Examples of the method for terminal treatment of the halogen atom of the copolymer include a method in which arylboronic acid is added and then heated and stirred. Examples of the terminal treatment method of the boron atom-containing group of the copolymer include a method in which an aryl halide is added as a terminal treatment agent and then heated and stirred.

There are no particular restrictions on the terminal treatment method for terminal residue X and the terminal treatment method for terminal residue Y, but it is preferable to carry out each independently. In addition, there is no special restriction | limiting in the order of each terminal process, It can select suitably.
Further, the terminal treatment may be performed before the purification of the copolymer, but may be performed after the purification of the copolymer. When the end treatment is performed after the copolymer purification, the copolymer and one of the end treatment agents (for example, aryl halide or aryltrialkyltin) are dissolved in an organic solvent, and then a reaction is performed by adding a transition metal catalyst such as a palladium catalyst. Further, the other end treatment agent (aryltrialkyltin or aryl halide) may be added to carry out the reaction. From the viewpoint of accelerating the reaction, it is preferable to perform heating and stirring during the terminal treatment, as in the case where the terminal treatment is performed before the purification of the copolymer. Moreover, it is also preferable to perform reaction under nitrogen conditions from a viewpoint of improving a yield. The reaction time is not particularly limited, but is usually 30 minutes or longer, preferably 1 hour or longer, and is usually 25 hours or shorter, preferably 10 hours or shorter.

The addition amount of the transition metal catalyst is not particularly limited, but is usually 5.0 × 10 ⁻³ molar equivalents or more with respect to the total amount of the compounds represented by formulas (3A) to (3C), preferably Is 1.0 × 10 ⁻² molar equivalent or more, and is usually 1.0 × 10 ⁻¹ molar equivalent or less, preferably 5.0 × 10 ⁻² molar equivalent or less. When the addition amount of the catalyst is within this range, the end treatment can be performed at a lower cost and at a higher conversion rate.

The addition amount of the terminal treatment agent for the alkylstannyl group at the time of the terminal treatment after the purification of the copolymer is not particularly limited, but the monomer having the alkylstannyl group used for the polymerization (3B and 3C, or 3A) ) Is usually 1.0 × 10 ⁻² molar equivalent or more, preferably 1.0 × 10 ⁻¹ molar equivalent or more, more preferably 1 molar equivalent or more, while usually 50 molar equivalent or less, Preferably it is 20 molar equivalents or less, More preferably, it is 10 molar equivalents or less. When the added amount of the end treatment agent is within this range, the end treatment can be performed at a lower cost and at a higher conversion rate.

The addition amount of the halogen atom end treatment agent at the end treatment after the formation of the copolymer is not particularly limited, but the amount of the monomer (3A and 3B, or 3C) having a halogen atom at the terminal used for polymerization is not limited. On the other hand, it is usually 1.0 × 10 ⁻² mole equivalent or more, preferably 1.0 × 10 ⁻¹ mole equivalent or more, more preferably 1 mole equivalent or more, and usually 50 mole equivalent or less, preferably 20 moles. The equivalent or less, more preferably 10 molar equivalent or less. When the added amount of the end treatment agent is within this range, the end treatment can be performed at a lower cost and at a higher conversion rate.

  Although there is no limitation in particular as a process performed after a polymerization reaction, Usually, the process of isolate | separating a copolymer is performed. When the terminal treatment of the copolymer is performed, it is preferable to perform a step of separating the copolymer after the terminal treatment. If necessary, further copolymer separation and purification may be performed prior to copolymer termination. From the viewpoint of obtaining the copolymer in a shorter processing step, it is preferable to carry out the terminal treatment of the copolymer, separation of the copolymer and purification of the copolymer in this order after the polymerization reaction.

As a method for separating the copolymer, for example, the reaction solution and a poor solvent are mixed to precipitate the copolymer, or the active species in the reaction solution is quenched with water or hydrochloric acid, and then the copolymer is extracted with an organic solvent. Examples include a method of distilling off the organic solvent.
Examples of the purification method of the copolymer include known methods such as reprecipitation purification, extraction using a Soxhlet extractor, gel permeation chromatography, or metal removal using a scavenger.

[2-1. Method for producing compounds represented by formulas (3A) to (3C)]
The compounds represented by the formulas (3A) and (3B) used as raw materials for the polymerization reaction are described in J. Org. Am. Chem. Soc. 2010, 132 (22), 7595-7597. In addition, the compound represented by the formula (3C) is described in J. Org. Mater. Chem. , 2011, 21, 3895, and J.A. Am. Chem. Soc. 2008, 130, 16144-16145.

A particularly preferred method for producing the compound represented by the formula (3C) includes a method using the compound represented by the following formula (4C) as a raw material. More specifically, the compound represented by the formula (3C) can be obtained by reacting the compound represented by the formula (4C) with a non-nucleophilic base and then reacting with an electrophile. . According to this method, it is possible to reduce the amount of by-products generated when producing the compound represented by the formula (3C), for example, having only one substituent Y. A small amount of by-products is preferable in that the copolymer according to the present invention obtained by the polymerization reaction can have a higher molecular weight.

In the formula (4C), Q and R ^{3 to} R ⁴ are the same as those defined in the formula (3C).
Examples of the non-nucleophilic base include a metal hydride, a metal alkoxide having a bulky substituent, an amine, a phosphazene base, a metal magnesium reagent having a bulky substituent (Grignard reagent), or a metal amide. . The use of a non-nucleophilic base is preferable in that it can effectively suppress nucleophilic attack on the condensed ring of the compound represented by formula (4C) and can suppress the formation of by-products. . From the viewpoint of high basicity and low nucleophilicity, the non-nucleophilic base is preferably a metal amide, and particularly preferably a metal amide having a bulky substituent.

The compound represented by the general formula (3C) is obtained by deprotonating the compound represented by the general formula (4C) using a non-nucleophilic base and then reacting the generated anion species with an electrophile. Can be obtained.
In the case where the substituent Y is an alkylstannyl group, the electrophile is not particularly limited, and examples thereof include a trialkyltin halide compound. When the substituent Y is a boric acid residue or a boric acid ester residue, the electrophile is not particularly limited, but a boric acid triester is preferably used. A compound having a boric acid ester residue obtained by a reaction with a boric acid triester can be isolated as it is, or after the boric acid ester residue is hydrolyzed and led to a boric acid residue, the compound is simply used. May be separated.

  The purification method after the reaction of the compound represented by the formula (3C) is not particularly limited, and a known method can be used. A particularly preferred method is a method using zeolite. More specifically, the obtained compound may be contacted with zeolite. This method is preferable because the compound can be purified more easily while preventing the compound represented by (3C) from being decomposed. As the zeolite, aluminosilicate zeolite such as aluminosilicate, metallosilicate or silicalite; or phosphate zeolite such as aluminophosphate, gallophosphate or berylphosphate is preferable.

As a method of bringing the obtained compound represented by the formula (3C) into contact with zeolite, (1) preparing a layer containing zeolite and allowing the compound to pass through, (2) charging the zeolite into the composition, Thereafter, a method of removing the zeolite, and the like can be mentioned.
There is no particular limitation on the amount of the non-nucleophilic base added to the compound represented by the formula (4C), and usually 2 mole equivalents or more of the non-nucleophilic base with respect to the compound represented by the formula (4C). A base is used. On the other hand, in order to reduce the amount of reagent used, the amount of non-nucleophilic base is usually 20 molar equivalents or less, preferably 10 molar equivalents or less, more preferably 5 molar equivalents or less. There is no particular limitation on the amount of the electrophile added to the compound represented by the formula (4C), and usually 2 mole equivalent or more of the electrophile is used with respect to the compound represented by the formula (4C). . On the other hand, in order to reduce the amount of the reagent used, the amount of the electrophilic reagent is usually 20 mole equivalents or less, preferably 10 mole equivalents or less, more preferably 5 mole equivalents or less.

The compound represented by the formula (4C) can be produced using a known method, but is particularly preferably produced using the method shown below. That is, the compound represented by the formula (4C) can be obtained by removing the silyl group from the compound obtained by adding a silyl group to the compound represented by the formula (4C). This method is preferable in that the compound represented by the formula (4C) can be obtained with higher yield.

  For example, the compound represented by the formula (4C) can be produced by a desilylation reaction using an acid of the compound represented by the following formula (5C).

In the formula (5C), Q and R ^{3 to} R ⁴ are the same as those defined in the formula (3C). In (5C), R ^{5 to} R ⁶ represent a silyl group which may have a substituent. The two substituents R ⁷ may be different from each other. Examples of the silyl group that may have a substituent include a trialkylsilyl group, a dialkylarylsilyl group, an alkyldiarylsilyl group, and a triarylsilyl group. The acid used in the desilylation reaction is not particularly limited, and an inorganic acid or an organic acid can be used. There are no particular limitations on the type of inorganic acid, and hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, or the like can be used. There are no particular limitations on the type of organic acid, and acetic acid, trifluoroacetic acid, oxalic acid, citric acid, benzoic acid, chlorobenzoic acid, p-toluenesulfonic acid, and the like can be used.

When Q is a silicon atom or a germanium atom, the compound represented by the formula (5C) can be obtained, for example, by treating a bithiophene compound with a base and reacting with a silyl halide or a germanyl halide. As a more specific example, 5,5′-bis (trimethylsilyl) -3,3′-dibromo-2,2′-bithiophene is treated with n-butyllithium, and R ³ R ⁴ SiCl ₂ , R ³ R By reacting ⁴ SiBr ₂ , R ³ R ⁴ GeCl ₂ , or R ³ R ⁴ GeBr ₂ , a compound represented by the formula (5C) can be obtained. A compound represented by the formula (3C) or (4C) is also synthesized using R ³ R ⁴ SiCl ₂ , R ³ R ⁴ SiBr ₂ , R ³ R ⁴ GeCl ₂ , or R ³ R ⁴ GeBr _2. sell. In this case, R ³ R ⁴ SiCl ₂ , R ³ R ⁴ SiBr ₂ , R ³ R ⁴ GeCl ₂ , or R ³ R ⁴ GeBr ₂ is preferably purified by distillation under reduced pressure. In order to carry out vacuum distillation at a vacuum degree that can be easily achieved and at a lower temperature, the number of carbon atoms of R ³ and R ⁴ is preferably 15 or less, and more preferably 8 or less.

<3. Organic Semiconductor Material Containing Copolymer According to the Present Invention>
The copolymer according to the present invention has solubility in a solvent and light absorption in a long wavelength region, and is suitable as an organic semiconductor material.
The organic semiconductor material according to the present invention includes at least the copolymer according to the present invention. The organic semiconductor material according to the present invention may contain one of the copolymers according to the present invention, or may contain two or more kinds in any combination. Further, the organic semiconductor material according to the present invention may be composed only of the copolymer according to the present invention, but contains other components (for example, other polymers, monomers, various additives, etc.). May be.

The organic semiconductor material according to the present invention is suitable as a material for an organic semiconductor layer or an organic active layer of an organic electronic device described later. In this case, an organic semiconductor material is preferably used after being formed into a film. In this case, physical properties such as the solubility of the copolymer according to the present invention in an organic solvent and its excellent processability are preferably used. A method of using the organic semiconductor according to the present invention in an organic electronic device will be described later.

The organic semiconductor material according to the present invention exhibits semiconductor characteristics. For example, in the field effect mobility measurement, the hole mobility (sometimes referred to as hole mobility) 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, particularly preferably 1.0 × 10 ⁻⁴ cm ² / Vs or more, On the other hand, the hole mobility is usually 1.0 × 10 ⁴ cm ² / Vs or less, preferably 1.0 × 10 ³ cm ² / Vs or less, more preferably 1.0 × 10 ² cm ² / Vs or less, particularly Preferably, it is 1.0 × 10 cm ² / Vs or less. As a method for measuring the hole mobility, there is an FET method. The FET method can be carried out by a method described in a known document (Japanese Patent Laid-Open No. 2010-045186).

The organic semiconductor material according to the present invention can be used alone or as a material of an organic semiconductor layer of an organic electronic device, but can also be mixed and / or laminated with other organic semiconductor materials. Other organic semiconductor materials that can be used in combination with the organic semiconductor material according to the present invention include poly (3-hexylthiophene) (P3HT), poly [2,6- (4,4-bis [2-ethylhexyl] -4H- Cyclopenta [2,1-b: 3,4-b ′] dithiophene) -alt-4,7- (2,1,3-benzothiadiazole)] (PCPDTBT), benzoporphyrin (BP), pentacene, etc. organic semiconductor materials and the like, further, perylene known as n-type semiconductor compound - bisimide, [6,6] - phenyl _{-C 61} - butyric acid methyl ester ([60] PCBM) or larger fullerenes _{C 70,} etc. PCBM with, [6,6] - phenyl _{-C 61} - butyric acid n- butyl ester ([60] PCBNB) or larger fullerenes _{C 70,} etc. Examples thereof include fullerene derivatives such as PCBNB, but are not particularly limited thereto.

  The organic semiconductor material according to the present invention may be used in the form of a solution. Since the copolymer according to the present invention has high stability when made into a solution, the solution containing the organic semiconductor material according to the present invention and the solvent, that is, the solution containing the copolymer according to the present invention and the solvent is applied by a coating method. Can be preferably used for forming an organic semiconductor layer. In this case, it is preferable that the semiconductor layer obtained by applying the solution exhibits the semiconductor characteristics described above.

  The solvent is not particularly limited as long as it can uniformly dissolve or disperse the copolymer according to the present invention. For example, aliphatic hydrocarbons such as hexane, heptane, octane, isooctane, nonane or decane; toluene, xylene, Aromatic hydrocarbons such as chlorobenzene or orthodichlorobenzene; lower alcohols such as methanol, ethanol or propanol; ketones such as acetone, methyl ethyl ketone, cyclopentanone or cyclohexanone; esters such as ethyl acetate, butyl acetate or methyl lactate Halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethane, trichloroethane or trichloroethylene; ethers such as ethyl ether, tetrahydrofuran or dioxane; dimethylformamide or dimethylacetate Amides such as bromide, and the like. Among them, preferred are aromatic hydrocarbons such as toluene, xylene, chlorobenzene or orthodichlorobenzene, and halogen hydrocarbons such as chloroform, methylene chloride, dichloroethane, trichloroethane or trichloroethylene.

<4. Electronic Device Containing Organic Semiconductor Material According to the Present Invention>
Next, the organic electronic device according to the present invention will be described. The organic electronic device according to the present invention is manufactured using the organic semiconductor material according to the present invention. That is, the organic electronic device according to the present invention includes the organic semiconductor material according to the present invention. As long as the organic semiconductor material according to the present invention can be applied, the type of the organic electronic device according to the present invention is not particularly limited. Examples include a light emitting element, a switching element, a photoelectric conversion element, an optical sensor using photoelectric conductivity, and the like.

Examples of the light emitting element include various light emitting elements used for display devices. Specific examples include a liquid crystal display element, a polymer dispersion type liquid crystal display element, an electrophoretic display element, an electroluminescent element, an electrochromic element, and the like.
Specific examples of the switching element include a diode (pn junction diode, Schottky diode, MOS diode, etc.), a transistor (bipolar transistor, field effect transistor (FET), etc.), a thyristor, and a composite element thereof (for example, TTL). Etc.).

Specific examples of the photoelectric conversion element include a thin film solar cell, a charge coupled device (CCD), a photomultiplier tube, and a photocoupler. Moreover, what utilized these photoelectric conversion elements is mentioned as an optical sensor using photoelectric conductivity.
In which part of the organic electronic device the organic semiconductor material according to the present invention is used is not particularly limited, and can be used in any part. In order to utilize the semiconductor characteristics of the organic semiconductor material according to the present invention, it is preferable to use the organic semiconductor material according to the present invention in the semiconductor layer of the organic electronic device. Particularly in the case of a photoelectric conversion element, the organic semiconductor layer containing the organic semiconductor material according to the present invention is usually used as an organic active layer.

<5. Photoelectric conversion element>
The photoelectric conversion element according to the present invention is a photoelectric conversion element including a pair of electrodes and an active layer disposed between the electrodes, and the active layer contains the copolymer according to the present invention.

[5-1. Configuration of photoelectric conversion element]
FIG. 1 shows an embodiment of a photoelectric conversion element according to the present invention. The photoelectric conversion element shown in FIG. 1 is a photoelectric conversion element used in a general organic thin film solar cell, but the photoelectric conversion element according to the present invention is not limited to that shown in FIG. A photoelectric conversion element 107 according to an embodiment of the present invention includes a base material 106, an anode 101, a hole extraction layer 102, an active layer 103 (a mixed layer of a p-type semiconductor material and an n-type semiconductor material), and an electron extraction layer 104. , And a layer structure including the cathode 105. Note that FIG. 1 illustrates an example of a photoelectric conversion element in which each layer is stacked in the order described above, but the photoelectric conversion element 107 includes a base material 106, a cathode 105, an electron extraction layer 104, an active layer 103, and holes. The structure which has the taking-out layer 102 and the anode 101 in this order may be sufficient. The active layer 103 may have a structure in which a p-type semiconductor material and an n-type semiconductor material are stacked. Further, the hole extraction layer 102 and the electron extraction layer 104 are not essential components and may be provided arbitrarily.

  The layer structure of the active layer 103 is preferably a mixed layer of a p-type semiconductor material and an n-type semiconductor material (sometimes referred to as a bulk heterojunction type), but may be another structure. For example, it may be a thin film laminated type in which a p-type semiconductor material and an n-type semiconductor material are laminated, or a structure having a mixed layer (i layer) of a p-type semiconductor material and an n-type semiconductor material in an intermediate layer of the thin film laminated type. . In addition, as the p-type semiconductor material of the active layer 103, it is preferable to use the copolymer according to the present invention.

  Further, another layer may be inserted between the layers of the photoelectric conversion element 107 to the extent that the functions of the layers described later are not affected.

The substrate 106, the anode 101, the hole extraction layer 102, the n-type semiconductor material of the active layer 103, the electron extraction layer 104, and the cathode 105 may be formed using known materials and methods. Specifically, it is as described in Solar Energy Materials & Solar Cells 96 (2012) 155-159, International Publication No. 2011-016430 or JP 2012-191194 A. Note that the p-type semiconductor material of the active layer 103 may also be used in combination with a p-type semiconductor material described in the above-mentioned publicly known document in addition to the copolymer according to the present invention. Moreover, the preferable film thickness of each layer which comprises the board | substrate 106 and the photoelectric conversion element 107 is also as having described in the said well-known literature. Note that among the materials described in the above-described publicly known documents, preferable materials for the layers constituting the substrate 106 and the photoelectric conversion element are described below.

  As the substrate 106, an inorganic material substrate such as a glass substrate, a plastic substrate such as polyethylene terephthalate, polyethylene naphthalate or polyimide, a substrate made of paper material such as paper or synthetic paper, and insulated from metals such as stainless steel, copper, titanium or aluminum Examples thereof include a substrate made of a composite material such as a surface coated or laminated for imparting properties. It is preferable to use a plastic substrate or a substrate made of a composite material as the material of the substrate 106 in that a lightweight and flexible photoelectric conversion element can be obtained.

  Examples of the cathode 105 include indium tin oxide (ITO), silver, copper, and aluminum.

  As the electron extraction layer 104, either an inorganic compound or an organic compound may be used, but titanium oxide (TiOx) or zinc oxide (ZnO) is preferable in terms of excellent film formation stability and reduced production cost.

  The LUMO energy level of the n-type semiconductor compound of the active layer 103 is not particularly limited. For example, the value with respect to the vacuum level calculated by a cyclic voltammogram measurement method is usually −4.0 eV or more, preferably − A material that is 3.9 eV or higher is preferred. Since the open-circuit voltage (Voc) depends on the difference between the HOMO energy level of the p-type semiconductor compound and the LUMO energy level of the n-type semiconductor compound, increasing the LUMO energy level of the n-type semiconductor compound increases Voc. Tend. On the other hand, if the LUMO energy level is too high, electron transfer from the p-type semiconductor compound is difficult to occur, and is usually −1.0 eV or less, preferably −2.0 eV or less, more preferably −3.0 eV or less. More preferably, it is −3.3 eV or less. When the LUMO energy level of the n-type semiconductor compound is in the above range, the open-circuit voltage (Voc) and the short-circuit current density (Jsc) can be increased at the same time.

  The HOMO energy level of the n-type semiconductor compound is not particularly limited, but is usually −5.0 eV or less, preferably −5.5 eV or less. On the other hand, it is usually −7.0 eV or more, preferably −6.6 eV or more. It is preferable that the HOMO energy level of the n-type semiconductor compound is −7.0 eV or more because light absorption of the n-type semiconductor compound can also be used for power generation. The HOMO energy level of the n-type semiconductor compound is preferably −5.0 eV or less from the viewpoint of preventing reverse movement of holes.

The electron mobility of the n-type semiconductor compound is not particularly limited, but is usually 1.0 × 10 ⁻⁶ cm ² / Vs or more, preferably 1.0 × 10 ⁻⁵ cm ² / Vs or more. 0 × 10 ⁻⁵ cm ² / Vs or more is more preferable, and 1.0 × 10 ⁻⁴ cm ² / Vs or more is more preferable. On the other hand, it is usually 1.0 × 10 ⁴ cm ² / Vs or less, preferably 1.0 × 10 ³ cm ² / Vs or less, and more preferably 5.0 × 10 ² cm ² / Vs or less. It is preferable that the electron mobility of the n-type semiconductor compound be in the above range in that an effect such as improvement in conversion efficiency can be obtained in combination with the copolymer of the present invention. As a method for measuring the electron mobility, an FET method can be mentioned, which can be performed by a method described in a known document (Japanese Patent Laid-Open No. 2010-045186).

The n-type semiconductor compound is preferably dissolved in an organic solvent because it is easy to achieve high photoelectric conversion efficiency in combination with the copolymer of the present invention. The solubility in toluene at 25 ° C. is preferably 0.5% by weight or more, more preferably 1.0% by weight or more, and further preferably 1.5% by weight or more. On the other hand, it is usually preferably 90% by weight or less, more preferably 80% by weight or less, and further preferably 70% by weight or less. When the solubility of the n-type semiconductor compound in toluene at 25 ° C. is 0.5% by weight or more, the dispersion stability of the n-type semiconductor compound in the solution is improved, and aggregation, sedimentation, separation, and the like are less likely to occur. Therefore, it is preferable.

  Specifically, a fullerene derivative having a substituent is preferable because it is easy to form an ideal phase separation structure with the copolymer of the present invention, and PCBM is particularly preferable.

  The hole extraction layer 102 is not limited, but is preferably a material having a Fermi level of −5.0 eV or less (or a work function of 5.0 eV or more). More preferably, the Fermi level is −5.1 eV or less (work function is 5.1 eV or more), and particularly preferably, the Fermi level is −5.2 eV or less (work function is 5.2 eV or more). When the Fermi level (or work function) is in the above range, holes can be easily extracted from the polymer of the present invention, and a photoelectric conversion element excellent in photoelectric conversion efficiency and durability can be provided. There is no particular limitation as long as the material satisfies such conditions. For example, polythiophene, polypyrrole, polyacetylene, triphenylenediamine, polyaniline, or the like is doped with a sulfonic acid and / or iodine or the like, a sulfonyl group. Examples thereof include polythiophene derivatives having a substituent, conductive organic compounds such as arylamine, and metal oxides such as molybdenum trioxide. Is preferred.

  The anode 101 is not particularly limited, and a conductive metal oxide such as indium tin oxide (ITO), a metal such as silver, gold, platinum, chromium, or cobalt, or an alloy thereof can be used.

<6. Solar Cell According to the Present Invention>
The photoelectric conversion element 107 according to the present invention is preferably used as a solar cell, particularly a solar cell element of a thin film solar cell.
FIG. 2 is a cross-sectional view schematically showing the configuration of a thin film solar cell as one embodiment of the present invention. As shown in FIG. 2, the thin film solar cell 14 of this embodiment includes a weather-resistant protective film 1, an ultraviolet cut film 2, a gas barrier film 3, a getter material film 4, a sealing material 5, and a solar cell element. 6, a sealing material 7, a getter material film 8, a gas barrier film 9, and a back sheet 10 are provided in this order. And light is irradiated from the side (downward in the figure) where the weather-resistant protective film 1 is formed, and the solar cell element 6 generates power. In addition, when using a highly waterproof sheet such as a sheet in which a fluororesin film is bonded to both surfaces of an aluminum foil as the back sheet 10 described later, the getter material film 8 and / or the gas barrier film 9 may not be used depending on the application. Good.

For the above-described configuration and the manufacturing method thereof, a well-known technique can be used, and specifically, those described in known documents such as International Publication No. 2011/016430 can be adopted.
There is no restriction | limiting in the use of the solar cell which concerns on this invention, especially the thin film solar cell 14 mentioned above, It can use for arbitrary uses. Examples of the field to which the thin-film solar cell according to the present invention is applied include building material solar cells, automobile solar cells, interior solar cells, railway solar cells, marine solar cells, airplane solar cells, and spacecrafts. Solar cells, 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 a solar cell may be installed on a substrate and used as a solar cell module. For example, as schematically shown in FIG. 3, a solar cell module 13 including a thin film solar cell 14 on a base material 12 is prepared and used at a place of use. For the base material 12, well-known techniques can be used, and specifically those described in publicly known documents such as International Publication No. 2011-016430 can be adopted.

  As a specific example, when a building material plate is used as the base material 12, a solar cell panel can be produced as the solar cell module 13 by providing the thin film solar cell 14 on the surface of the plate material.

Hereinafter, embodiments of the present invention will be described by way of examples. However, the present invention is not limited to these examples as long as the gist of the present invention is not exceeded. The items described in the examples were measured by the following methods.
[Method for measuring weight average molecular weight and number average molecular weight]
The weight average molecular weight (Mw) and number average molecular weight (Mn) in terms of polystyrene were determined by gel permeation chromatography (GPC). The molecular weight distribution (PDI) represents Mw / Mn.

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

[Storage stability test of copolymer-containing ink]
The storage stability test of the copolymer-containing ink was carried out by the following method. 2 mg of the copolymer was placed in a 2 mL screw vial, and o-xylene was added thereto to a concentration of 1.5% by mass. The vessel was sealed with a lid and heated until the copolymer dissolved. The resulting copolymer-containing ink was cooled to room temperature and the time until gelation was measured. As a method for determining gelation, the gel was gelled when no fluidity was observed after standing for 1 minute with the screw vial turned upside down after a predetermined time. Specifically, the container was removed from the heat source and gelled after 5 minutes from the time of standing at room temperature, and whether gelled after 1 hour was determined.

[Measurement method of photoelectric conversion efficiency]
A 4 mm square metal mask is attached to the photoelectric conversion element, and an air mass (AM) 1.5 G and an irradiance 100 mW / cm 2 solar simulator (WXS-100SU-10, AM1.5G, manufactured by Wacom Denso Co., Ltd.) are used as the irradiation light source. The current-voltage characteristics between the ITO electrode and the silver electrode were measured with a source meter (Keisley, Model 2400). The open circuit voltage Voc (V), the short circuit current density Jsc (mA / cm 2), the shape factor FF, and the photoelectric conversion efficiency PCE (%) were calculated. Here, the open circuit voltage Voc is a voltage value when the current value = 0 (mA / cm ² ), and the short circuit current density Jsc is a current density when the voltage value = 0 (V). The form factor FF is a factor representing the internal resistance, and is represented by the following expression when the maximum output is Pmax.
FF = Pmax / (Voc × Jsc)
Further, the photoelectric conversion efficiency PCE is given by the following equation when the incident energy is Pin.
PCE = (Pmax / Pin) × 100 = (Voc × Jsc × FF / Pin) × 100
<Synthesis Example 1: Synthesis of Compound E2>

  In a 200 mL four-necked eggplant flask under a nitrogen atmosphere, 4,4-bis (2-ethylhexyl) -2,6-bis (trimethylsilyl) -dithieno [3,2-b: 2 ′, 3′-d] silole ( Compound E1, Non-Patent Document J. Am. Chem. Soc. 2008, 130, 16144-16145, synthesized, 1.03 g, 1.786 mmol) was added and dissolved in chloroform (50 mL). Further, trifluoroacetic acid (0.265 mL, 3.573 mmol) was added dropwise, followed by stirring for about 3.5 hours. Water was added to the reaction solution, the lower layer was washed with water, dried over sodium sulfate, and concentrated under reduced pressure. By dissolving in hexane and subjecting to silica gel column chromatography (solvent: hexane), 4,4-bis (2-ethylhexyl) -dithieno [3,2-b: 2 ′, 3′-d] silole (compound E2 ) Was obtained as a pale yellow oil (702 mg, 94% yield).

Compound E2: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 7.18 (d, 2H, J = 4.8 Hz), 7.08 (d, 2H, J = 4.8 Hz), 1.43- 1.35 (m, 2H), 1.28-1.09 (m, 16H), 0.98-0.80 (m, 10H), 0.75 (d, 6H, J = 7.3 Hz).
<Synthesis Example 2: Synthesis of Compound E3>

Under a nitrogen atmosphere, Compound E2 (100 mg, 0.239 mmol) was placed in a 20 mL Schlenk tube, dissolved in tetrahydrofuran (THF, 2.5 mL), and cooled to -78 ° C. Further, a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentration 1.11 M, 0.258 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0 M, 0.287 mL, 1.2 eq) was added dropwise, and the temperature was gradually raised to room temperature. After cooling again to −78 ° C., a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentration 1.11 M, 0.258 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0 M, 0.287 mL, 1.2 eq) was added dropwise, and the temperature was gradually raised to room temperature. After cooling to −78 ° C. again, a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentration 1.11 M, 0.258 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0 M, 0.310 mL, 1.3 eq) was added dropwise, and the temperature was gradually raised to room temperature. Water was added to the reaction solution, followed by extraction with hexane, and the organic layer was washed with water. The organic layer was dried over sodium sulfate, filtered, concentrated under reduced pressure, and then dried under vacuum, whereby 4,4-bis (2-ethylhexyl) -2,6-bis (trimethyltin) -dithieno [3, 2-b: 2 ′, 3′-d] silole (compound E3) was quantitatively obtained as a yellow-green oil.

Compound E3: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 7.07 (s, 2H), 1.45-1.37 (m, 2H), 1.32-1.08 (m, 16H) 0.99-0.80 (m, 10H), 0.77 (t, 6H, J = 7.3 Hz), 0.36 (s, 18H).
<Synthesis Example 3: Synthesis of Compound E5>

  In a 300 mL four-necked eggplant flask under nitrogen atmosphere, 4,4-bis (2-ethylhexyl) -dithieno [3,2-b: 2 ′, 3′-d] germole (compound E4, J. Am. Chem. Soc., 2011, 133, 10062-10065, 7.43 g, 16.0 mmol) was added, dissolved in anhydrous tetrahydrofuran (THF, 150 mL), and cooled to -78 ° C. Further, a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentration 1.11 M, 17.3 mL, 1.2 eq) was added dropwise and stirred for 30 minutes. Subsequently, a solution of trimethyltin chloride in tetrahydrofuran (Aldrich, 1.0M, 19.2 mL, 1.2 eq) was added dropwise and stirred for 30 minutes. Further, a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentration 1.11 M, 17.3 mL, 1.2 eq) was added dropwise, stirred for 30 minutes, and a tetrahydrofuran solution of trimethyltin chloride (Aldrich). Manufactured, 1.0M, 19.2 mL, 1.2 eq) was added dropwise and stirred for 30 minutes. Again, a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentration 1.11 M, 17.3 mL, 1.2 eq) was added dropwise, stirred for 30 minutes, and a tetrahydrofuran solution of trimethyltin chloride (Aldrich). Manufactured, 1.0M, 20.8 mL, 1.3 eq) was added dropwise, and the mixture was stirred for 30 minutes and warmed to room temperature. Water was added to the reaction solution, followed by extraction with hexane, and the organic layer was washed with water. The organic layer was dried over sodium sulfate and filtered through zeolite. The organic layer was concentrated under reduced pressure, washed with methanol, and then dried under vacuum, whereby 4,4-bis (2-ethylhexyl) -2,6-bis (trimethyltin) -dithieno [3,2- b: 2 ′, 3′-d] germol (compound E5) was quantitatively obtained as a yellow-green oil.

Compound E5: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 7.07 (s, 2H), 1.48 (m, 2H), 1.35-1.12 (m, 20H), 0.85 -0.75 (m, 12H), 0.37 (s, 18H).
Example 1: Synthesis of Copolymer 1

1,3-Dibromo-5-octyl obtained by referring to a method described in a known document (Organic Letters Vol. 6, pp. 3383-1384, 2004) as a monomer in a 50 mL two-necked eggplant flask under a nitrogen atmosphere -4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound E6, 57.8 mg, 0.137 mmol), known literature (Organic Letters 6, 3383-1384, 2004) 1,3-dibromo-5-isopentyl-4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound E7, 52.1 mg) 0.138 mmol), compound E3 (218.9 mg, 0.294 mmol) obtained in Synthesis Example 2 was added, and tetrakis was added. (Triphenylphosphine) palladium (0) (10 mg, 3 mol%), heterogeneous complex catalyst Pd-EnCatTPP30 (Aldrich, 22 mg, 3 mol%), toluene (4.9 mL), and N, N-dimethylformamide ( 1.2 mL) and stirred at 90 ° C. for 1 hour and then at 100 ° C. for 10 hours. The reaction solution was diluted 4-fold with toluene and further stirred with heating for 0.5 hour, then, as a terminal treatment, trimethyl (phenyl) tin (0.04 mL) was added and stirred with heating for 8 hours, and further bromobenzene (0. 2 mL) was added, and the mixture was heated and stirred for 8 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was separated by filtration to obtain the desired copolymer 1 (144 mg). The weight average molecular weight Mw was 1.56 × 10 ⁵ and the PDI was 3.1.
<Example 2: Synthesis of copolymer 2>

In a 50 mL two-necked eggplant flask under a nitrogen atmosphere, the compound E6 (91.4 mg, 0.216 mmol) used in Example 1 was used as a monomer and described in known literature (Organic Letters 6, 3383-1384, 2004). 1,3-dibromo-5-hexadecyl-4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound E8, 22.8 mg, 0. 054 mmol), compound E5 (229.0 mg, 0.290 mmol) obtained in Synthesis Example 3 was added, tetrakis (triphenylphosphine) palladium (0) (10 mg, 3 mol%), heterogeneous complex catalyst Pd-EnCatTPP30 (Aldrich, 22 mg, 3 mol%), toluene (4.8 mL), and N, N- Put methylformamide (1.1 mL), 1 hour at 90 ° C., followed by stirring for 10 hours at 100 ° C.. The reaction solution was diluted 4-fold with toluene and further stirred with heating for 0.5 hour, then, as a terminal treatment, trimethyl (phenyl) tin (0.04 mL) was added and stirred with heating for 8 hours, and further bromobenzene (0. 2 mL) was added, and the mixture was heated and stirred for 8 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was separated by filtration to obtain the desired copolymer 2 (150 mg). The weight average molecular weight Mw was 2.13 × 10 ⁵ and the PDI was 4.5.
<Example 3: Synthesis of copolymer 3>

In a 50 mL two-necked flask under nitrogen, as a monomer, the compound E6 used in Example 1 (116 mg, 0.274 mmol), a method described in a known document (Organic Letters 6, Vol. 3381-3384, 2004) was referred. 1,3-dibromo-5- (p-xylyl) -4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound E9, 114 mg, 0.274 mmol) Compound E3 (439.0 mg, 0.590 mmol) obtained in Synthesis Example 2 was added, tetrakis (triphenylphosphine) palladium (0) (20 mg, 3 mol%), heterogeneous complex catalyst Pd-EnCatTPP30 (Aldrich) , 44 mg, 3 mol%), toluene (9.2 mL), and N, N-dimethyl Put formamide (2.2 mL), 1 hour at 90 ° C., followed by stirring for 10 hours at 100 ° C.. The reaction solution was diluted 4 times with toluene and further stirred with heating for 0.5 hour, then, as a terminal treatment, trimethyl (phenyl) tin (0.4 mL) was added and stirred with heating for 8 hours, and further bromobenzene (4 mL). Was added with stirring for 8 hours, the reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was separated by filtration to obtain the desired copolymer 3 (325 mg). The weight average molecular weight Mw was 1.94 × 10 ⁵ and the PDI was 3.5.
<Example 4: Synthesis of copolymer 4>

  In a nitrogen atmosphere, in a first 50 mL two-necked eggplant flask (A), the compound E6 (118 mg, 0.280 mmol) used in Example 1 and the compound E3 (224 mg, 0) obtained in Synthesis Example 2 were used as monomers. .301 mmol), tetrakis (triphenylphosphine) palladium (0) (10 mg, 3 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (manufactured by Aldrich, 22 mg, 3 mol%), toluene ( 4.7 mL) and N, N-dimethylformamide (1.1 mL) were added, and the mixture was stirred at 90 ° C. for 1 hour and then at 100 ° C. for 1 hour.

Next, in a second 50 mL two-necked eggplant flask (B) under a nitrogen atmosphere, the compound E9 (116 mg, 0.280 mmol) used in Example 3 and the compound E3 obtained in Synthesis Example 2 were used as monomers. (224 mg, 0.301 mmol), tetrakis (triphenylphosphine) palladium (0) (10 mg, 3 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (manufactured by Aldrich, 22 mg, 3 mol%) ), Toluene (4.7 mL), and N, N-dimethylformamide (1.1 mL) were added, and the mixture was stirred at 90 ° C. for 1 hour and then at 100 ° C. for 1 hour. Here, the reaction solution of the flask (B) was added to the reaction solution of the flask (A) and stirred at 100 ° C. for 10 hours. After diluting 4 times with toluene and heating and stirring at 100 ° C. for another 0.5 hours, as a terminal treatment, trimethyl (phenyl) tin (0.4 mL) was added and heating and stirring at 100 ° C. for 8 hours. Further, bromobenzene (4.0 mL) was added, and the mixture was stirred with heating at 100 ° C. for 8 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was separated by filtration to obtain the target copolymer 4 (361 mg). The resulting copolymer 4 had a weight average molecular weight Mw of 1.94 × 10 ⁵ and a PDI of 3.7.
<Comparative Example 1: Synthesis of Copolymer 5>

In a nitrogen atmosphere, a compound of E6 (138 mg, 0.33 mmol) used in Example 1 and Compound E3 (255 mg, 0.34 mmol) obtained in Synthesis Example 2 were added as monomers to a 50 mL two-necked eggplant flask, Tetrakis (triphenylphosphine) palladium (0) (12 mg, 3 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (manufactured by Aldrich, 23 mg, 3 mol%), toluene (5.3 mL), and N , N-dimethylformamide (1.3 mL) was added, and the mixture was stirred at 90 ° C. for 1 hour and then at 100 ° C. for 10 hours. After the reaction solution was diluted 4-fold with toluene and heated and stirred at 100 ° C. for another 0.5 hours, as a terminal treatment, trimethyl (phenyl) tin (0.3 mL) was added and heated and stirred at 100 ° C. for 8 hours. Bromobenzene (1.5 mL) was further added, and the mixture was heated and stirred at 100 ° C. for 8 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was separated by filtration to obtain the target copolymer 5 (174 mg). The weight average molecular weight Mw of the obtained copolymer 5 was 1.37 * 10 < ⁵ >, and PDI was 3.3.
<Comparative Example 2: Synthesis of Copolymer 6>

In Comparative Example 1, synthesis was performed in the same manner as in Comparative Example 1 except that Compound E5 obtained in Synthesis Example 3 was used instead of Compound E3 obtained in Synthesis Example 2, and the target copolymer 6 ( 392 mg). The resulting copolymer 6 had a weight average molecular weight Mw of 1.87 × 10 ⁵ and a PDI of 5.7.
Example 5 Synthesis of Copolymer 7

In a 50 mL two-necked eggplant flask under nitrogen, the method described in Example 1 as compound E6 (169.3 mg, 0.400 mmol), known literature (Organic Letters 6: 3381-3384, 2004) as a monomer. 1,3-dibromo-5- (p-xylyl) -4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound E9, 41.5 mg, 0.100 mmol), compound E3 (400.0 mg, 0.537 mmol) obtained in Synthesis Example 2 was added, tetrakis (triphenylphosphine) palladium (0) (20 mg, 3 mol%), heterogeneous complex catalyst Pd -EnCatTPP30 (Aldrich, 44 mg, 3 mol%), toluene (9.2 mL), and N, N-di Placed a solution of triethylsilane (2.2 mL), 1 hour at 90 ° C., followed by stirring for 10 hours at 100 ° C.. The reaction solution was diluted 4 times with toluene and further stirred with heating for 0.5 hour, then, as a terminal treatment, trimethyl (phenyl) tin (0.4 mL) was added and stirred with heating for 8 hours, and further bromobenzene (4 mL). Was added with stirring for 8 hours, the reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was separated by filtration to obtain the desired copolymer 7 (270 mg). The weight average molecular weight Mw was 1.65 × 10 ⁵ and the PDI was 2.6.
<Example 6: Synthesis of copolymer 8>

In a nitrogen atmosphere, in a first 50 mL two-necked flask (A), as a monomer, the compound E6 (432 mg, 1.02 mmol) used in Example 1 and the compound E3 (800 mg, 1) obtained in Synthesis Example 2 were used. 0.07 mmol), tetrakis (triphenylphosphine) palladium (0) (40 mg, 3 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (manufactured by Aldrich, 88 mg, 3 mol%), toluene ( 18.4 mL) and N, N-dimethylformamide (4.4 mL) were added, and the mixture was stirred at 90 ° C. for 1 hour and then at 100 ° C. for 1 hour.
Next, in a second 50 mL two-necked eggplant flask (B) in a nitrogen atmosphere, the compound E9 (104 mg, 0.250 mmol) used in Example 3 and the compound E3 obtained in Synthesis Example 2 were used as monomers. (200 mg, 0.269 mmol), tetrakis (triphenylphosphine) palladium (0) (10 mg, 3 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 22 mg, 3 mol%) ), Toluene (4.6 mL), and N, N-dimethylformamide (1.1 mL) were added, and the mixture was stirred at 90 ° C. for 1 hour and then at 100 ° C. for 1 hour. Here, the reaction solution of the flask (B) was added to the reaction solution of the flask (A) and stirred at 100 ° C. for 10 hours. After diluting 4 times with toluene and heating and stirring at 100 ° C. for another 0.5 hours, as a terminal treatment, trimethyl (phenyl) tin (1.0 mL) was added and heating and stirring at 100 ° C. for 8 hours. Further, bromobenzene (10.0 mL) was added, and the mixture was stirred with heating at 100 ° C. for 8 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was separated by filtration to obtain the target copolymer 8 (670 mg). The resulting copolymer 8 had a weight average molecular weight Mw of 3.10 × 10 ⁵ and a PDI of 3.7.
<Comparative Example 3: Synthesis of Copolymer 9>

1,3-dibromo-5- (2-ethylhexyl)-obtained by referring to a method described in known literature (J. Am. Chem. Soc. 2010, 132, 7595-7597) instead of the compound E6 Comparative example except that 4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound E8 (250 mg, 0.59 mmol) was used, and other reagents were used in the same ratio) The target copolymer 9 was obtained in the same manner as in 1. The obtained copolymer 9 had a weight average molecular weight Mw of 2.00 × 10 ⁵ and a PDI of 3.2.

  Each of the copolymers obtained in Examples 1 to 6 and Comparative Examples 1 to 3 was subjected to a storage stability test of the copolymer-containing ink by the above method. The results are listed in Table 1 below. In Table 1, x indicates that gelation was confirmed within 5 minutes from the time when the container was removed from the heat source and allowed to stand at room temperature, and ○ indicates that gelation was not confirmed after 5 minutes, but 1 hour. Gelation was confirmed at a later time point, and ◎ represents that gelation was not confirmed even at a time point after 1 hour. Moreover, in Table 1, molar ratio (%) represents the molar ratio of the repeating unit represented by Formula (2A) and (2B) among the repeating units which comprise each copolymer.

<Example 7: Production of photoelectric conversion element 1>

  Copolymer 7 obtained in Example 5 as a p-type semiconductor compound, and a mixture of PC61BM (phenyl C61 butyric acid methyl ester) and PC71BM (phenyl C71 butyric acid methyl ester) which are fullerene compounds as an n-type semiconductor compound (Frontier Carbon Corporation, nanom spectra E123) was dissolved in a mixed solvent (volume ratio 9: 1) of o-xylene and tetralin in a nitrogen atmosphere so as to have a concentration of 1.8% by mass. At this time, the mass ratio of the p-type semiconductor compound and the n-type semiconductor compound was 1: 2. This solution was stirred and mixed on a hot stirrer at a temperature of 80 ° C. for 1 hour. The solution after stirring and mixing was filtered through a 1 μm polytetrafluoroethylene (PTFE) filter to obtain an ink for coating an active layer.

A glass substrate (manufactured by Geomatic Co., Ltd.) patterned with an indium tin oxide (ITO) transparent conductive film is subjected to ultrasonic cleaning with acetone, followed by ultrasonic cleaning with isopropanol, followed by drying with nitrogen blow and UV-ozone treatment. went. Next, a mixed solvent of 2-methoxyethanol (Aldrich) and ethanolamine (Aldrich) at a concentration of 105 mg / mL of zinc (II) acetate dihydrate (Wako Pure Chemical Industries) (volume ratio 100: The solution (about 0.1 mL) dissolved in 3) was spin-coated at a speed of 3000 rpm, subjected to UV-ozone treatment, and then heated in an oven at 200 ° C. for 15 minutes to form an electron extraction layer. By bringing the substrate on which the electron extraction layer is formed into a glove box, heat-treating at 150 ° C. for 3 minutes in a nitrogen atmosphere, and spin-coating the active layer coating ink (0.12 mL) prepared as described above after cooling. An active layer was formed. Further, a molybdenum trioxide (MoO 3) film having a thickness of 1.5 nm as a hole extraction layer and a silver film having a thickness of 100 nm as an electrode layer are sequentially formed on the active layer by a resistance heating vacuum deposition method. A 5 mm square photoelectric conversion element was produced. The photoelectric conversion efficiency of the thus produced photoelectric conversion element was measured by the above method. The results are shown in Table 2 together with the thickness of the active layer.
<Example 8: Production of photoelectric conversion element 2>

A photoelectric conversion element was produced in the same manner as in Example 1 except that the copolymer 8 obtained in Example 6 was used as the p-type semiconductor compound, and the photoelectric conversion efficiency was measured. The results are shown in Table 1.
<Comparative Example 4: Production of photoelectric conversion element 3>

A photoelectric conversion element was produced in the same manner as in Example 1 except that the copolymer 5 obtained in Comparative Example 1 was used as the p-type semiconductor compound, and the photoelectric conversion efficiency was measured. The results are shown in Table 1.

As described above, although the copolymers of Comparative Examples 1 to 3 have a high molecular weight, it is understood that the storage stability of the ink containing these polymers is not good. On the other hand, it can be seen that all of the copolymers of Examples 1 to 6, which are copolymers according to the present invention, have a high molecular weight and good storage stability of the ink containing the copolymer.
In particular, in the copolymer 9 of Comparative Example 3 in which the substituent of the nitrogen atom of the imide thiophene ring of the copolymer 5 of Comparative Example 1 is replaced with an 2-ethylhexyl group (branched alkyl group) from an octyl group (linear alkyl group), the ink The storage stability of was not improved.

However, in the case of the copolymer 2 described in Example 2 having both of these substituents (octyl group and 2-ethylhexyl group), the solubility was improved and the storage stability of the ink was good. Furthermore, as shown in Examples 3 to 6, the imidothiophene ring in which the substituent that the nitrogen atom has is an o-xylenyl group (aromatic group) is also an imidothiophene ring in which the substituent that the nitrogen atom has is an octyl group. By using in combination, solubility was improved.
As described above, when the copolymer having only the repeating unit represented by the formula (1A) or the formula (1B) is used as the imidothiophene ring, the formula (1A) and the formula ( By combining the linearity of the substituent of 1B) and the effect of the spatial spread of the substituent, it is possible to increase the storage stability of the ink without impairing the properties of the copolymer.

  Thus, the storage stability of the ink containing the copolymer containing the repeating unit represented by the formula (1A), the repeating unit represented by the formula (1B) and the repeating unit represented by the formula (1C) is high, Since it is easy to carry out coating film formation using this ink, it can be seen that the copolymer according to the present invention is suitable for use as a photoelectric conversion element material.

  Moreover, the photoelectric conversion element produced using the copolymer which concerns on this invention improved the photoelectric conversion efficiency significantly compared with the photoelectric conversion element produced using the conventional copolymer. Also from this result, a photoelectric conversion element having high photoelectric conversion efficiency can be produced by using the copolymer according to the present invention.

DESCRIPTION OF SYMBOLS 101 Anode 102 Hole taking-out layer 103 Active layer 104 Electron taking-out layer 105 Cathode 106 Base material 107 Photoelectric conversion element 1 Weatherproofing protective film 2 Ultraviolet cut film 3, 9 Gas barrier film 4, 8 Getter material film 5, 7 Sealing material 6 Solar cell element 10 Back sheet 12 Base material 13 Solar cell unit 14 Thin film solar cell

Claims (7)

A copolymer comprising a repeating unit represented by the following formula (1A), a repeating unit represented by the formula (1B), and a repeating unit represented by the formula (1C).
(In Formula (1A), Formula (1B) and Formula (1C), A ¹ and A ² each independently represent an atom selected from Group 16 of the Periodic Table, and Q is selected from Group 14 of the Periodic Table) R ¹ represents a linear alkyl group that may have a substituent, R ² represents a branched alkyl group that may have a substituent, or a cycloalkyl that may have a substituent A group, an aromatic hydrocarbon group which may have a substituent, or a heterocyclic group which may have a substituent, each of R ³ and R ⁴ independently has a hetero atom; Represents a good hydrocarbon group.) The copolymer of Claim 1 containing the repeating unit represented by a following formula (2A) and a formula (2B).
(In Formula (2A) and Formula (2B), Q ¹ and Q ² each independently represent an atom selected from Group 14 of the periodic table, and A ¹ , A ² , R ^{1 to} R ⁴ represent the above formula ( The same meaning as in 1), R ⁵ and R ⁶ each independently represents a hydrocarbon group optionally having a hetero atom.   An organic semiconductor material comprising the copolymer according to claim 1.   An organic electronic device comprising the organic semiconductor material according to claim 3.   The organic electronic device according to claim 4 which is a photoelectric conversion element.   The organic electronic device according to claim 4 which is a solar cell.   A solar cell module comprising the organic electronic device according to claim 6.