JP5736456B2 - Conjugated block copolymer and photoelectric conversion element using the same - Google Patents

Description

  The present invention relates to a conjugated block copolymer that forms an organic thin film that serves as an organic photoelectric conversion layer of a photoelectric conversion element, and a photoelectric conversion element produced using the same.

  Solar cells are attracting attention as a powerful energy source that is friendly to the environment. At present, inorganic materials such as silicon-based materials such as single crystal silicon, polycrystalline silicon, and amorphous silicon, and compound semiconductor materials such as GaAs, CIGS, and CdTe are used as photoelectric conversion elements for solar cells. These photoelectric conversion elements have a relatively high photoelectric conversion efficiency, but are expensive compared to other power supply costs. The cause of the high cost is the process in which the semiconductor thin film must be manufactured under high vacuum and high temperature. Therefore, organic semiconductor cells using organic semiconductors such as conjugated polymers and organic crystals and organic dyes are being studied as semiconductor materials that are expected to simplify the manufacturing process. Since these organic semiconductor materials can be formed into a film by a coating method or a printing method, they are attracting attention because the manufacturing process is simplified, mass production is possible, and inexpensive organic solar cells can be obtained.

An organic solar cell has a structure in which an organic photoelectric conversion layer is provided between two different electrodes. Generally, the organic photoelectric conversion layer is formed from a mixture of a conjugated polymer and a fullerene derivative. Representative examples include compositions containing poly (3-hexylthiophene) as a conjugated polymer and [6,6] -phenyl C ₆₁ butyric acid methyl ester (PC ₆₁ BM) as a fullerene derivative.

  The problem of the organic solar cell is to increase the photoelectric conversion efficiency, and in particular, reports have been made on improving the photoelectric conversion efficiency by changing the morphology of the organic photoelectric conversion layer. Methods for changing the morphology of the organic photoelectric conversion layer include, for example, a method of treating with heat or solvent vapor, a method of devising a solvent that dissolves a conjugated polymer or fullerene derivative, a method of adding a high-boiling compound, and a low volatilization rate of the solvent. The method of doing is mentioned.

  As another approach, there has been a report aiming at improving the photoelectric conversion efficiency by controlling the morphology of the organic photoelectric conversion layer using a conjugated block copolymer. It is known that block copolymers usually undergo microphase separation if they have a sufficient molecular weight. Also in the conjugated block copolymer, it has been reported that the conversion efficiency is improved by microphase separation and controlling the structure of the active layer which is an organic photoelectric conversion layer (Patent Documents 1 to 8, Non-Patent Document 1). ~ 7).

  Non-Patent Document 1 proposes a conjugated block copolymer in which a polar group is introduced into one block of the block copolymer to improve the microphase separation performance. However, since the polarity is very high and the affinity with the fullerene derivative, which is an N-type organic semiconductor, is small, the fullerene derivative easily aggregates, and sufficient conversion efficiency cannot be obtained. This may be because the fullerene derivative is aggregated and a good morphology is not formed.

  Similarly, in the case of a block copolymer of a conjugated polymer and a non-conjugated polymer, high performance cannot be expected because the non-conjugated polymer does not contribute to power generation. Moreover, even in the case of a block copolymer of a conjugated polymer and a conjugated polymer, in the case of a block copolymer containing a conjugated polymer typified by polythiophene, phase separation between a crystal part and an amorphous part has been observed, Often not microphase separation of block copolymers. The reason for this is that since it is difficult to synthesize these conjugated block copolymers, two types of monomers having similar side chains are often used. Therefore, the resulting conjugated block copolymers also have a similar skeleton. It becomes a thing, and a co-crystal is made or it melt | dissolves in an amorphous part. Moreover, when forming a co-crystal, the micro phase separation peculiar to a block copolymer is not formed, but crystal-amorphous phase separation is only observed. In such a case, the morphology control by microphase separation, which is an advantage of using a conjugated block copolymer, cannot be achieved, and for example, an acceptor material such as a fullerene derivative can be unevenly distributed in one polymer domain of the block copolymer. Therefore, improvement in conversion efficiency cannot be expected so much.

  For this reason, what can control morphology by micro phase separation and can obtain sufficient photoelectric conversion efficiency is desired.

International Publication No. 2009/056496 US Pat. No. 7,452,958 US Patent Application Publication No. 2008/0315751 JP 2007-2111237 A Japanese Patent Laid-Open No. 2008-2223015 JP 2010-074127 A JP 2010-43217 A Japanese Patent No. 4126019

High Performance Polymers, 2007, Vol. 19, pages 684-699 Macromolecules, 2007, 40, 4733-4735 Macromolecules, 2008, 41, 5289-5294 Macromolecules, 2009, 42, 7008-7015 Macromolecules, 2010, 43, 3306-3313 Advanced Materuals, 2010, Vol. 22, pp. 763-768 Macromolecules, 2011, 44, 530-539

  The present invention has been made in order to solve the above-mentioned problems. A conjugated block copolymer having good solubility in a solvent and capable of forming an organic thin film with controlled morphology by microphase separation, and It aims at providing the photoelectric conversion element which has the photoelectric conversion efficiency which was excellent using the organic thin film to contain.

  The conjugated block copolymer according to claim 1, which has been made to achieve the above object, contains a divalent heterocyclic group in the main chain and is substituted with a fluorine atom or a hydroxyl group. A conjugated block copolymer containing at least two kinds of conjugated polymer blocks containing a side chain which is an alkyl group or an alkoxy group, wherein the conjugated polymer block has a maximum solubility parameter; A difference in solubility parameter from a conjugated polymer block having a minimum parameter is from 0.6 to 2.0.

  The conjugated block copolymer according to claim 2 is the conjugated block copolymer according to claim 1, wherein the conjugated polymer block includes at least one thiophene ring as a part of a chemical structure. And a divalent heterocyclic group having at least one heterocyclic skeleton selected from a carbazole skeleton, a dibenzosilole skeleton, and a dibenzogermol skeleton in the main chain.

  The conjugated block copolymer according to claim 3 is the one according to claim 1, wherein the conjugated polymer block includes a cyclopentadithiophene diyl group, a dithienopyrrole diyl group, and a dithienosilole diyl group. At least one divalent heterocyclic group selected from dithienogermolediyl group, benzodithiophenediyl group, naphthodithiophenediyl group, thienothiophenediyl group, thienopyrroledionediyl group and diketopyrrolopyrrolediyl group It is contained in the main chain.

  The conjugated block copolymer according to claim 4 is the one described in any one of claims 1 to 3, wherein two types of the conjugated polymer block are minimum in the divalent heterocyclic group. A conjugated polymer block in which a side chain of an alkyl group or an alkoxy group having 8 carbon atoms is bonded to the same or different divalent heterocyclic group is an alkyl group or an alkoxy group having 6 carbon atoms at the maximum It is characterized by being a conjugated polymer block to which side chains are bonded.

  The conjugated block copolymer according to claim 5 is the conjugated block copolymer according to claim 3, wherein the total number of carbon atoms in one side chain of one conjugated polymer block and the side chain of the other conjugated polymer block. The difference from the total number of carbon atoms is 6 or more and 16 or less.

  The conjugated block copolymer according to claim 6 is the one described in any one of claims 1 to 3, wherein two types of the conjugated polymer block are fluorine atoms in the divalent heterocyclic group. A conjugated polymer block to which a side chain of an alkyl group or an alkoxy group which is not contained is bonded, and an alkyl group substituted with at least three fluorine atoms on the same or different divalent heterocyclic group, or It is characterized by being a conjugated polymer block to which a side chain which is an alkoxy group is bonded.

  The composition of Claim 7 contains the conjugated block copolymer in any one of Claims 1-6, and a fullerene derivative, It is characterized by the above-mentioned.

  The organic thin film of Claim 8 contains the conjugated block copolymer in any one of Claims 1-6, It is characterized by the above-mentioned.

  The organic thin film element of Claim 9 equips a board | substrate with the organic thin film of Claim 8. It is characterized by the above-mentioned.

  The photoelectric conversion element according to claim 10 is characterized in that the organic thin film according to claim 6 is sandwiched between at least two electrodes.

  The conjugated block copolymer of the present invention contains at least two kinds of conjugated polymer blocks, and microphase separation can be formed by adjusting the solubility parameter thereof. With this microphase separation structure, it is possible to form an organic thin film with high photoelectric conversion efficiency with controlled morphology.

  The composition of the present invention forms an organic thin film in which the morphology is controlled by microphase separation using a conjugated block copolymer which is an organic semiconductor material and has a good affinity with an acceptor material contained together. be able to.

  The organic thin film of this invention can provide the photoelectric conversion element which has the outstanding photoelectric conversion efficiency.

  The photoelectric conversion element of the present invention has excellent photoelectric conversion performance, and can be applied to various photoelectric conversion devices using a photoelectric conversion function and an optical rectification function.

  Hereinafter, although the form for implementing this invention is demonstrated in detail, the scope of the present invention is not limited to these forms.

  The conjugated block copolymer of the present invention is a block copolymer in which at least two types of conjugated polymer blocks, for example, conjugated polymer block A and conjugated polymer block B are copolymerized and bonded. The conjugated polymer block constituting each block is a polymer composed of a conjugated divalent monomer, which contains a divalent heterocyclic group in its main chain and is substituted with a fluorine atom or a hydroxyl group. There are those containing a side chain which is an alkyl group which may be substituted or an alkoxy group which may be substituted with a fluorine atom or a hydroxyl group. Here, the main chain refers to the longest chain of a compound composed of a divalent heterocyclic group. The conjugated divalent monomer constituting the conjugated polymer block is a divalent group in which electrons of bonds in the molecule are delocalized, and is a compound composed of a divalent heterocyclic group. .

  Specific examples of the divalent heterocyclic group include dibenzosiloldiyl group, dibenzogermolediyl group, dibenzofurandiyl group, carbazolediyl group, thiophenediyl group, furandyl group, pyrrolediyl group, benzothiadiazolediyl group, and thienylene. Examples include vinylene diyl group and benzotriazole diyl group. Examples of the thiophenediyl group include a thiophenediyl group having a monocyclic structure and a thiophenediyl group having a condensed ring structure, and a thiophenediyl group having a condensed ring structure is more preferable. As the thiophene diyl group having a condensed ring structure, cyclopentadithiophene diyl group, dithienopyrrole diyl group, dithienosilole diyl group, dithienogermol diyl group, benzodithiophene diyl group, naphthodithiophene diyl group, thienothiophene Examples thereof include a diyl group, a thienopyrrole dione diyl group, and a diketopyrrolopyrrole diyl group. The thiophenediyl group of these condensed ring structures may be a polycyclic structure in which a monocyclic or condensed aromatic ring or heterocyclic ring is directly bonded. Examples of the monocyclic or condensed aromatic ring or heterocyclic ring include thiophene, furan, benzene, naphthalene, pyrrole, and pyridine, and thiophene is preferable. These aromatic rings or heterocyclic rings directly bonded to the condensed thiophenediyl group are conjugated with a divalent heterocyclic group constituting the main chain and π electrons, and are part of the main chain skeleton.

  Among these divalent heterocyclic groups, a condensed π-conjugated skeleton containing at least one thiophene ring as a part of the chemical structure, carbazole, from the viewpoint that the morphology is easy to control and the performance as a photoelectric conversion element is high. A skeleton, a dibenzosilole skeleton, or a dibenzogermol skeleton is preferable, and a condensed π-conjugated skeleton including at least one thiophene ring as a part of the chemical structure is more preferable. On the other hand, a thiophenediyl group having a monocyclic structure is easy to synthesize, but the wavelength range of light to be absorbed is a short wavelength, and when used for a photoelectric conversion element, the photoelectric conversion efficiency may not be high.

  The connection structure of two or more kinds of conjugated polymer blocks contained in the conjugated block copolymer of the present invention is not particularly limited. In the case of containing two kinds of conjugated polymer blocks, for example, an AB type diblock copolymer, an AB type triblock copolymer, an AB type AB block tetrablock copolymer And A-B-A-B-A type pentablock copolymer. In the case of containing three types of conjugated polymer blocks, examples include an ABC type triblock copolymer and an ABAC type tetrablock copolymer.

  The bonding mode of the conjugated block copolymer is not particularly limited as long as microphase separation of the conjugated block copolymer is formed. As the bonding mode, a linear conjugated block copolymer in which the ends of the conjugated polymer block are bonded to each other, or a T-type conjugated block copolymer in which the end of the conjugated polymer block is bonded to other than the end of the conjugated polymer block. It may be. The binding sites may be linked by π conjugation or may be bound by a non-conjugated structure.

  The monomer unit of the conjugated polymer block is not limited to one unit having a structure in which only the monomer unit -a- is repeated, for example, as long as it has a plurality of constant repeating structures in the conjugated polymer block. This includes a structure in which a plurality of valent heterocyclic groups are linked, for example, the monomer unit -ab- as one unit. That is, the complete alternating copolymer block of the monomer unit -a- and the monomer unit -b- is a homopolymer of the monomer unit -ab as long as it is a repeating unit having the same substituent. It shall be regarded as a block. In the conjugated polymer block A and the conjugated polymer block B, the total number of only carbon atoms constituting the ring structure excluding a substituent in one type of monomer unit including up to the embodiment of the monomer unit -ab- Is preferably 6-30. In the case of such a monomer unit -ab-, the alkyl group or alkoxy group which may be substituted with a fluorine atom or a hydroxyl group as a side chain is at least the monomer unit -a- or the monomer unit-. What is necessary is just to couple | bond with either of b-.

  More specifically, for example, when the cyclopentadithiophene diyl group (a) and the benzothiadiazole diyl group (b) are alternately bonded, the adjacent cyclopentadithiophene diyl group (a) and the benzothiadiazole diyl group The group (b) can be regarded as a monomer unit of the present invention as one monomer unit -ab.

  The conjugated block copolymer of the present invention includes a conjugated polymer block A having a maximum solubility parameter and a conjugated polymer block B having a minimum solubility parameter among the solubility parameters of the conjugated polymer block constituting each block. The difference is 0.6 or more and 2.0 or less. The difference between the maximum value and the minimum value of the solubility parameter is preferably 0.6 or more and 1.8 or less, and more preferably 0.6 or more and 1.6 or less.

  When the difference between the maximum value and the minimum value of the solubility parameter is 0.6 or more, the conjugated block copolymer can be microphase-separated. When it is less than 0.6, the polarities of the conjugated polymer blocks of the respective blocks are close to each other, and phase separation is difficult. It is also important that the difference between the maximum and minimum solubility parameters is 2.0 or less. When the difference between the maximum value and the minimum value of the solubility parameter is larger than 2.0, the solubility in the solvent is remarkably lowered, and it becomes difficult to obtain a thin film, or the conjugated block copolymer has a micelle structure. When a thin film is produced by dissolving in a solvent, a morphology that retains a micelle structure is formed, and an ideal microphase separation structure cannot be formed, and high conversion efficiency cannot be obtained when a photoelectric conversion element is obtained. There is a case.

  An ideal microphase separation structure indicates that two or more block components contained in a conjugated block copolymer have a co-continuous structure. It is also important that one domain of these phase separation structures contains a fullerene derivative that is more electron accepting material than the other domains. By forming such a morphology, charges can be transported to the electrode without recombination or deactivation, so that the short-circuit current density is increased and a high-performance photoelectric conversion element can be manufactured.

  The solubility parameter of the conjugated polymer block can be controlled by its molecular structure. As a method for controlling the solubility parameter, for example, when a diblock copolymer is considered, it is possible to adjust the solubility parameter by changing the main chain skeleton of the conjugated polymer block. However, since the main chain skeleton of the conjugated polymer is generally similar, it is preferable to adjust the solubility parameter by the side chain structure or the side chain density. When controlling the solubility parameter by changing the side chain structure, it can be controlled by the number of carbons in the side chain, the type of atoms bonded to the side chain carbon, and the functional group bonded to the side chain, but the conjugated polymer block In order to impart crystallinity, it is important that the side chain is an alkyl group or an alkoxy group which may be substituted with a fluorine atom or a hydroxyl group. Here, the side chain means a portion having carbon branched from a conjugated main chain. When the solubility parameter is controlled by changing the side chain structure of the copolymer block having a plurality of side chains in the main chain, the solubility parameter can be controlled by changing the structure of different side chains. Here, different side chains refer to side chains having different structures in each copolymer block. The number of carbon atoms in the side chain is preferably 1 or more, more preferably 2 or more, and further preferably 3 or more. Further, the number of carbon atoms in the side chain is preferably 20 or less, and more preferably 16 or less. Here, the carbon number of the side chain means the carbon number per side chain bonded to the main chain.

  When the conjugated polymer block has a plurality of different types of side chains, at least one of them may be an alkyl group or an alkoxy group which may be substituted with a fluorine atom or a hydroxyl group. The content of the side chain other than the alkyl group or alkoxy group is not particularly limited as long as the difference in solubility parameter can be adjusted. Examples of such other side chains include acyl groups and ester groups.

  It is not preferable to control the solubility parameter by the type of the functional group bonded to the carbon of the alkyl group or alkoxy group which may be substituted with a fluorine atom or a hydroxyl group as a side chain. For example, introduction of a functional group such as an ether group, an epoxy group, an amino group, an amide group, or an iodine atom is not preferable in that the packing of the polymer is inhibited, the crystallinity is lowered, and the hole movement does not occur smoothly. In addition, when the functional group bonded to the alkyl group or alkoxy group which may be substituted with a fluorine atom or a hydroxyl group is a bulky functional group, crystallization is inhibited, and hole movement does not occur smoothly.

  On the other hand, unlike other halogen atoms, a fluorine atom is useful because it does not inhibit crystallization but rather promotes crystallization. A hydroxyl group is also useful because it can be expected to be crystallized by hydrogen bonding. However, when two or more hydroxyl groups are present per side chain, crystallization may be inhibited by forming strong hydrogen bonds between them or by hydrogen bonding between side chains in one polymer. This is not preferable.

  Specific examples of the preferred alkyl group substituted with a hydroxyl group include hydroxymethyl group, 2-hydroxyethyl group, 3-hydroxypropyl group, 3-hydroxyisopropyl group, 4-hydroxybutyl group, 3-hydroxybutyl group, 3 -Hydroxyisobutyl group, hydroxy tert-butyl group, 5-hydroxypentyl group, 4-hydroxyisopentyl group, 6-hydroxyhexyl group, 6-hydroxy-2-ethylhexyl group, 7-hydroxyheptyl group, 8-hydroxyoctyl group , 9-hydroxynonyl group, 10-hydroxydecyl group, 12-hydroxydodecyl group, 16-hydroxyhexadecyl group, 8-hydroxy-3,7-dimethyloctyl group, etc. other than ω-hydroxyalkyl group and ω-position An alkyl group having a hydroxy group The

  Specific examples of the preferred alkoxy group substituted with a hydroxyl group include a hydroxymethoxy group, a 2-hydroxyethoxy group, a 3-hydroxypropoxy group, a 3-hydroxyisopropoxy group, a 4-hydroxybutoxy group, a 3-hydroxybutoxy group, 3-hydroxyisobutoxy group, hydroxy tert-butoxy group, 5-hydroxypentyloxy group, 4-hydroxyisopentyloxy group, 6-hydroxyhexyloxy group, 6-hydroxy-2-ethylhexyloxy group, 7-hydroxyheptyloxy Group, 8-hydroxyoctyloxy group, 9-hydroxynonyloxy group, 10-hydroxyoxy group, 12-hydroxydodecyloxy group, 16-hydroxyhexadecyloxy group, 8-hydroxy-3,7-dimethyloctyloxy group, etc. of Except ω- hydroxyalkoxy group or ω- position and an alkoxy group having a hydroxy group.

  When adjusting the difference in solubility parameter using the number of carbons in the side chain, it is possible to adjust to the desired difference in solubility parameter by combining conjugated polymer blocks having different alkyl groups or alkoxy groups. Among them, a combination of a conjugated polymer block mainly containing at least a side chain having 8 carbon atoms and a conjugated polymer block mainly containing at most a side chain having 6 carbon atoms is preferable, and has 8 or more carbon atoms. A combination of a conjugated polymer block mainly containing 20 or less side chains and a conjugated polymer block mainly containing side chains having 3 to 6 carbon atoms is more preferred. Also, from the viewpoint of adjusting the solubility parameter difference, there is a certain difference between the total number of carbon atoms in the side chain of one conjugated polymer block and the total number of carbon atoms in the side chain of the other conjugated polymer block. preferable. The difference in the total number of carbon atoms in the side chain is preferably 6 or more and 16 or less, and more preferably 6 or more and 10 or less.

  When the conjugated polymer block constituting the conjugated block copolymer has a plurality of side chains, when comparing at least one different side chain among the side chains contained in each monomer unit, It is preferred that the combined block has a minimum of 8 carbon side chains and the other conjugated polymer block has a maximum of 6 carbon side chains.

  In the case of a conjugated polymer block having a side chain with a small number of carbon atoms, it is possible to increase the value of the solubility parameter. However, if the number of carbon atoms is too small, the solubility of the conjugated block copolymer in the solvent decreases. Therefore, a preferable organic thin film cannot be obtained. In the case of a conjugated polymer block having a side chain with a large number of carbon atoms, it is possible to reduce the value of the solubility parameter, but when the number of carbon atoms is as large as 20 or more, it is difficult for the conjugated polymer block chains to approach each other, The movement of charges and excitons between conjugated polymer block chains is difficult to occur, and components that do not contribute to photoelectric conversion increase, resulting in a decrease in short-circuit current density. These side chains do not have to be all side chains limited to the number of carbon atoms in the conjugated polymer block, and can be combined with other side chains.

  Specific examples of preferred alkyl groups when adjusting the solubility parameter of the conjugated polymer block using the carbon number of the side chain include methyl, ethyl, n-propyl, isopropyl, n-butyl, and isobutyl groups. , Sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, tert-pentyl group, n-hexyl group, isohexyl group, 2-ethylhexyl group, n-heptyl group, n-octyl group, Examples include n-nonyl group, n-decyl group, n-hexadecyl group, 3,7-dimethyloctyl group, n-dodecyl group and the like.

  Specific examples of preferred alkoxy groups when adjusting the solubility parameter of the conjugated polymer block using the carbon number of the side chain include methoxy group, ethoxy group, n-propyloxy group, isopropyloxy group, n-butoxy group, n-hexyl group, n-octyloxy group, n-decyloxy group, 2-ethylhexyloxy group, n-dodecyloxy group, n-hexadecyloxy group, 3,7-dimethyloctyloxy group, n-dodecyloxy group, etc. Is mentioned.

  When adjusting the difference in solubility parameter depending on the type of atom bonded to the side chain carbon, the difference in solubility parameter can be adjusted by combining conjugated polymer blocks having side chains in which different atoms are bonded to the side chain carbon. Is possible. In that case, fluorine atoms are particularly useful because they have the greatest Pauling electronegativity. When fluorine atoms are bonded to carbon instead of hydrogen atoms, the number of fluorine atoms depends on the number of carbons in the side chain, but when the number of carbon atoms is 6 or more, the number of fluorine atoms contains 3 or more. A side chain is preferred, a side chain containing 5 or more is more preferred, and a side chain containing 5 or more and 13 or less is more preferred. When the polymer block has a plurality of side chains, when comparing at least one different side chain among the side chains contained in each monomer unit, one polymer block contains 3 or more fluorine atoms It is preferable to have a side chain.

By combining such a conjugated polymer block having a side chain and a conjugated polymer block having a side chain not containing a fluorine atom, a conjugated block copolymer having a desired difference in solubility parameter can be obtained. In this case, the solubility parameter of the conjugated polymer block having a side chain containing a fluorine atom decreases as the number of fluorine atoms increases. In the case of a conjugated polymer block having a side chain with a small number of fluorine atoms, the solubility parameter can be increased. However, if the number of fluorine atoms is too small, the difference between the maximum value and the minimum value of the solubility parameter becomes small.

  On the other hand, in the case of a conjugated polymer block having a side chain with a large number of fluorine atoms, the solubility parameter can be reduced, but if the number of fluorine atoms is too large, the difference between the maximum and minimum solubility parameters becomes too large. End up. Moreover, when there are too many fluorine atoms, a conjugated block copolymer will become difficult to melt | dissolve in a solvent. These side chains containing fluorine atoms do not have to be all side chains in the conjugated polymer block, and may be combined with other side chains.

  When adjusting the solubility parameter of a conjugated polymer block by designing a side chain in which a fluorine atom is bonded to a side chain carbon, specific examples of preferred fluorinated alkyl groups include trifluoromethyl group, 2,2,2-trimethyl. Fluoroethyl group, 2,2,2,1,1-pentafluoroethyl group, 4,4,4-trifluorobutyl group, 6,6,6-trifluorohexyl group, 5,5,6,6,6 -Pentafluorohexyl group, 7,7,7-trifluoroheptyl group, 4,4,5,5,6,6,7,7,7-nonafluoroheptyl group, 8,8,8-trifluorooctyl group , 7,7,8,8,8-pentafluorooctyl group, 5,5,6,6,7,7,8,8,8-nonafluorooctyl group, Fluoroalkyl group That.

  When adjusting the solubility parameter of the conjugated polymer block by designing a side chain in which a fluorine atom is bonded to a side chain carbon, specific examples of preferred fluorinated alkoxy groups include trifluoromethoxy group, 2,2,2-trimethyl Fluoroethoxy group, 2,2,2,1,1-pentafluoroethoxy group, 4,4,4-trifluorobutoxy group, 6,6,6-trifluorohexyloxy group, 5,5,6,6, 6-pentafluorohexyloxy group, 7,7,7-trifluoroheptyloxy group, 4,4,5,5,6,6,7,7,7-nonafluoroheptyloxy group, 8,8,8- Ω- such as trifluorooctyloxy group, 7,7,8,8,8-pentafluorooctyloxy group, 5,5,6,6,7,7,8,8,8-nonafluorooctyloxy group Trifle B and methyl alkoxy group or a perfluoroalkoxy group.

Although there are several methods for measuring and calculating the solubility parameter, the Bicerano method is used in the present invention. Other methods include, for example, the Hildebrand method, Small method, Fedors method, Van Krevelen method, Hansen method, Hoy method, Ascadskii method, Okitsu method, etc. Cannot be used because it cannot be calculated or is not accurate. The calculation method by the Bicerano method is described in “Prediction of Polymer Properties, 3rd Ed.” (2002), CRC Press, written by Jozef Bicerano. The unit of the solubility parameter is MPa ^1/2 . Various computer software can be used when calculating solubility parameters using the Bicerano method. Examples of the computer software include Scigress Explorer Professional 7.6.0.52 (Fujitsu) and Polymer-Design Tools (DTW Associates, Inc). When dealing with elements that have no data in the Bicerano method, substitute elements that are the same element in the periodic table and that have a smaller cycle number. For example, when there is no silicon data, the solubility parameter calculated with the structure substituted with carbon is used.

  In the conjugated block copolymer of the present invention, it is necessary to calculate a solubility parameter for the conjugated polymer block constituting each block of the conjugated block copolymer. When the conjugated polymer block constituting each block of the conjugated block copolymer is a random copolymer, the solubility parameter of the random copolymer is calculated as shown in the following formula (A).

[Solubility parameter of random copolymer] = Σ (δi × φi) (A)
δi = Solubility parameter of a polymer consisting only of i units that are components of a random copolymer φi = Weight fraction of i units that are components of a random copolymer (Σφi = 1)

  The mass ratio of each of the two or more conjugated polymer blocks contained in the conjugated block copolymer of the present invention is not particularly limited, but is preferably 95: 5 to 5:95 mass ratio, and 90:10 to 10 : 90 mass ratio is more preferable, and it is further more preferable in it being 85: 15-15: 85. Of the two or more types of conjugated polymer blocks contained in the conjugated block copolymer, it is preferable that the content of the conjugated polymer block giving higher photoelectric conversion efficiency is larger.

  The number average molecular weight of the conjugated block copolymer is not particularly limited, but is preferably 600 to 1,000,000 g / mol and more preferably 5,000 to 500,000 g / mol from the viewpoint of hole mobility and mechanical properties. It is preferably 10,000 to 200,000 g / mol. Here, the number average molecular weight means a molecular weight in terms of polystyrene by gel permeation chromatography.

  In the conjugated block copolymer, at least one block is preferably a crystalline polymer from the viewpoint of hole mobility. The crystalline polymer here is a polymer in which a part of the polymer is crystallized or in a liquid crystal state. Discrimination of the crystalline polymer can be analyzed by X-ray diffraction or DSC. In the present invention, the weak polymer packing state observed only by the aromatic ring π-π stack by the X-ray diffraction method is judged as having crystallinity.

  In the conjugated block copolymer of the present invention, a divalent group other than the divalent heterocyclic group can be copolymerized in the conjugated block copolymer and in the conjugated polymer block constituting each block. it can. When copolymerizing a divalent group other than a divalent heterocyclic group, the copolymerization rate is preferably 30% by mass or less, more preferably 20% by mass or less, based on the conjugated block copolymer. More preferably, it is 10 mass% or less. When the copolymerization rate is too high, the performance of the photoelectric conversion element may deteriorate. Specific examples of the divalent group other than the divalent heterocyclic group include an acetylene group and an arylene group.

  The conjugated block copolymer of the present invention may contain a conjugated polymer in addition to the exemplified conjugated polymer block. The content is preferably 50% by mass or less, more preferably 30% by mass or less, and more preferably 20% by mass from the viewpoint of controlling the morphology and the conversion efficiency of the photoelectric conversion element obtained by controlling the morphology. % Or less is more preferable. The conjugated polymer other than the conjugated block copolymer of the present invention is preferably a conjugated polymer having the same structure as one block of the conjugated block copolymer of the present invention.

  Furthermore, the conjugated block copolymer may contain other non-conjugated polymer blocks as long as it contains two or more kinds of conjugated polymer blocks. The content of the non-conjugated polymer block is not particularly limited as long as it does not decrease the conversion efficiency of the photoelectric conversion element, but is preferably 50% by mass or less, and preferably 30% by mass or less with respect to the total mass of the conjugated block copolymer. More preferred is 10% by mass or less. Such non-conjugated polymer blocks are not involved in the solubility parameter in the present invention.

  As an example of the production method of the conjugated block copolymer of the present invention, each reaction step and production method will be described in detail.

  As a first method for producing a conjugated block copolymer, at least two kinds of conjugated polymer blocks constituting each block, for example, conjugated polymer block A and conjugated polymer block B are synthesized separately, There is a method of connecting the two (hereinafter, referred to as “connection method”). As a second method, there is a method in which the conjugated polymer block A and the conjugated polymer block B are sequentially polymerized by pseudo-living polymerization (hereinafter sometimes referred to as “sequential polymerization method”). As a third method, there is a method of polymerizing the conjugated block B in the presence of the conjugated polymer block A (hereinafter sometimes referred to as “macroinitiator method”). As the linking method, sequential polymerization method, and macroinitiator method, an optimum method can be used depending on the conjugated block copolymer to be synthesized. .

Coupling method, as shown in the following reaction formula (I), the out the coupling reaction with the compound B-M ^p with Compound A-X and the conjugated polymer block B having a conjugated polymer block A in the presence of a catalyst Can be manufactured.

In the formula (I), A and B are conjugated polymer blocks, X is a halogen atom, M ^p is boronic acid, boronic acid ester, -MgX, -ZnX, -SnR ^a ₃ (where R ^a has 1 to 4 carbon atoms) A straight-chain alkyl group, and X is as defined above.

In the conjugated polymer block A and the conjugated polymer block B, terminal substituents may be exchanged, and as shown in the following reaction formula (II), the compound BX having the conjugated polymer block B and the conjugated polymer block the compound a-M ^p with a can be prepared by carrying out the coupling reaction in the presence of a catalyst.

In the formula (II), B and A are conjugated polymer blocks, X is a halogen atom, M ^p is boronic acid, boronic acid ester, -MgX, -ZnX, -SnR ^a ₃ (where R ^a has 1 to 4 carbon atoms) A straight-chain alkyl group, and X is as defined above.

According to the following reaction formula (III), the monomers M ^q1 -YM ^q1 and M ^q2 -ZM ^q2 are reacted in the presence of a catalyst, and the conjugated polymer block A or conjugated heavy is reacted by a so-called coupling reaction. Compound AX or compound BX containing combined block B can be prepared. Y and M represent a heterocyclic skeleton constituting at least a part of the monomer unit of the conjugated block copolymer of the present invention.

In formula (III), M ^q1 and M ^q2 are not the same and are each independently a halogen atom, or a boronic acid, boronic acid ester, —MgX, —ZnX, —SnR ^a ₃ (wherein R ^a has 1 to 4 carbon atoms) A represents a copolymer of Y and Z, and M ^p represents a boronic acid, a boronic acid ester, —MgX, —ZnX, —SnR ^a ₃ . . That is, when M ^q1 is a halogen atom, M ^q2 is boronic acid, boronic acid ester, —MgX, —ZnX, —SnR ^a ₃ , and conversely, when M ^q2 is a halogen atom, M ^q1 is boronic acid, boronic acid ester, -MgX, -ZnX, -SnR ^a ₃

Conjugated polymer block A or a conjugated polymer block B may be carried out a coupling reaction using a compound represented as compound ^{M q1 -Y-M} q1 Compound ^{M q2 -Z-M} q2 the formula ^{Ar-M r} It is also possible to manufacture by. However, Ar is an aryl group, ^{M r} represents ^{M p} or X, ^{M p} is boronic acid, boronic acid _{^{ester, -MgX, -ZnX, -SnR a 3}} (R a represents an alkyl group having 1 to 4 carbon atoms) , X represents a halogen atom.

In this way, the functional group for linking only to one end group of the polymer block A and the polymer block B, such as the compound ^AX , the compound ^BX , the compound A-M ^p , and the compound B-M ^p. It becomes easy to introduce.

  When the main chain skeleton of the conjugated polymer block A or the conjugated polymer block B of the compound AX or the compound BX is polythiophene, the conjugated polymer block A or the conjugated polymer is obtained by the pseudo-living polymerization method described in the sequential polymerization method. Block B can also be manufactured.

  Next, the sequential polymerization method will be described in detail. The sequential polymerization method is an effective method particularly when polythiophene is used as the main chain skeleton of both the conjugated polymer block A and the conjugated polymer block B. The basic polymerization reaction can be produced using the method shown below. The order of producing the conjugated polymer block may be the conjugated polymer block B after the conjugated polymer block A, or vice versa, and the optimum order is selected according to the intended conjugated block copolymer. it can.

In an inert solvent, the following chemical formula (IV)

(Wherein W is a divalent thienylene group which may have a substituent, X is a halogen atom, and two X's may be the same or different); , Grignard reagent represented by the following chemical formula (V)

(In the formula (V), R ′ is an alkyl group having 1 to 10 carbon atoms, and X is a halogen atom) The Grignard metathesis reaction, which is an exchange reaction with an organomagnesium halogen compound, represents the following chemical formula (VI)

  (In the formula (VI), W is a divalent thienylene group which may have a substituent, X is a halogen atom, and two X's are the same or different).

A conjugated block copolymer is obtained from the obtained organomagnesium compound (VI) by a so-called coupling reaction in a solvent in the presence of a metal complex catalyst. A series of reactions is shown in the schematic reaction formula (VII).

  In formula (VII), W of the resulting conjugated block copolymer is a copolymer composed of a divalent thienylene group which may have a substituent.

  Next, the macro initiator method will be described in detail. The macroinitiator method is a method in which the conjugated polymer block B is polymerized by allowing the terminal functionalized conjugated polymer block A to coexist in the initial stage of polymerization of the conjugated polymer block B or in the middle of polymerization. The order in which the conjugated polymer block is produced may be obtained by polymerizing the conjugated polymer block B in the presence of the conjugated polymer block A, or vice versa, depending on the target conjugated block copolymer. You can choose.

According to the following reaction formula (VIII), the conjugated polymer block A ^AX and the monomers M ^q1 -YM ^q1 and M ^q2 -ZM ^q2 are reacted in the presence of a catalyst to form a so-called cup. The conjugated block copolymer of the present invention can be obtained after the polymerization by bonding the terminal of the conjugated polymer block A and the polymerizable monomer of the conjugated polymer block B or the polymer block B during the polymerization by a ring reaction. it can. Further, by reacting an ^{M q1 -Y-M} q1 and ^{M q2 -Z-M} q2 is monomer in the presence of ^{A-M p} and catalyst is a conjugated polymer block A according to the following reaction formula (IX) The conjugated block copolymer of the present invention is obtained after the polymerization by bonding the terminal of the conjugated polymer block A and the polymerizable monomer of the conjugated polymer block B or the polymer block B during the polymerization by a coupling reaction. be able to.

In formula (VIII) and formula (IX), M ^q1 and M ^q2 are not the same and are each independently a halogen atom, or a boronic acid, boronic acid ester, —MgX, —ZnX, —SnR ^a ₃ (where R ^a is C represents a linear alkyl group having 1 to 4 carbon atoms, X represents the same as above, A and B represent a copolymer of Y and Z, M ^p represents boronic acid, boronic ester, -MgX, -ZnX,- Represents SnR ^a ₃ . That is, when M ^q1 is a halogen atom, M ^q2 is boronic acid, boronic acid ester, —MgX, —ZnX, —SnR ^a ₃ , and conversely, when M ^q2 is a halogen atom, M ^q1 is boronic acid, boronic acid ester, -MgX, -ZnX, -SnR ^a ₃

  It is necessary to use a transition metal complex as a catalyst for both the linking method, sequential polymerization method and macroinitiator method. Usually, transition metal complexes belonging to groups 3 to 10 of the periodic table (Group 18 long-period type periodic table), especially 8 to 10 are listed. Specifically, known complexes such as Ni, Pd, Ti, Zr, V, Cr, Co, and Fe can be used. Of these, Ni complexes and Pd complexes are more preferable. Moreover, as a ligand of the complex to be used, tridentate phosphine coordination such as trimethylphosphine, triethylphosphine, triisopropylphosphine, tri-t-butylphosphine, tricyclohexylphosphine, triphenylphosphine, tris (2-methylphenyl) phosphine Diphenylphosphinomethane (dppm), 1,2-diphenylphosphinoethane (dppe), 1,3-diphenylphosphinopropane (dppp), 1,4-diphenylphosphnobutane (pdbb), 1,3- Bidentate phosphine compounds such as bis (dicyclohexylphosphino) propane (dcpp), 1,1′-bis (diphenylphosphino) ferrocene (dppf), 2,2-dimethyl-1,3-bis (diphenylphosphino) propane Lico; tetramethyl ester Diamine, bipyridine, it is preferable that such a nitrogen-containing ligands such as acetonitrile is contained.

  The amount of the complex used varies depending on the kind of the conjugated block copolymer to be produced together with the linking method, the sequential polymerization method, and the macroinitiator method, but is preferably 0.001 to 0.1 mol with respect to the monomer. . If the amount of the catalyst is too large, it will cause a decrease in the molecular weight of the resulting polymer, which is also disadvantageous economically. On the other hand, if the amount is too small, the reaction rate becomes slow and stable production becomes difficult.

  Solvents that can be used for the production of the conjugated block copolymer need to be properly used depending on the type of the conjugated block copolymer to be produced, but are generally commercially available for both the linking method, sequential polymerization method and macroinitiator method. A solvent can be selected. For example, ether solvents such as tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, dimethyl ether, ethyl methyl ether, diethyl ether, dipropyl ether, butyl methyl ether, t-butyl methyl ether, dibutyl ether, cyclopentyl methyl ether, diphenyl ether , Aliphatic or alicyclic saturated hydrocarbon solvents such as pentane, hexane, heptane, cyclohexane, aromatic hydrocarbon solvents such as benzene, toluene, xylene, alkyl halide solvents such as dichloromethane and chloroform, chlorobenzene, di Aromatic aryl halide solvents such as chlorobenzene, amide solvents such as dimethylformamide, diethylformamide, N-methylpyrrolidone, water, and mixtures thereof And the like.

  The amount of the organic solvent used is preferably in the range of 1 to 1000 times by weight with respect to the monomer of the conjugated block copolymer to be produced, from the viewpoint of the solubility of the resulting conjugate and the stirring efficiency of the reaction solution. Is preferably 10 times by weight or more, and preferably 100 times by weight or less from the viewpoint of reaction rate.

  The polymerization temperature varies depending on the type of conjugated block copolymer to be produced. The linking method, sequential polymerization method and macroinitiator method are usually carried out in the range of -80 ° C to 200 ° C. Although the pressure of a reaction system is not specifically limited, 0.1-10 atmospheres is preferable. The reaction is usually carried out at around 1 atm. Moreover, although reaction time changes with the polymer block A and the polymer block B to manufacture, it is 20 minutes-100 hours normally.

  Conjugated block copolymers obtained by the linking method, sequential polymerization method and macroinitiator method are, for example, reprecipitation, solvent removal under heating, solvent removal under reduced pressure, and solvent removal with steam (steam stripping). The conjugated block copolymer can be separated and obtained from the reaction mixture by a normal operation for isolating the conjugated block copolymer from the solution. The obtained crude product can be purified by washing or extraction using a commercially available solvent using a Soxhlet extractor.

  For example, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, dimethyl ether, ethyl methyl ether, diethyl ether, dipropyl ether, butyl methyl ether, t-butyl methyl ether, dibutyl ether, cyclopentyl methyl ether, diphenyl ether and ether solvents , Aliphatic or alicyclic saturated hydrocarbon solvents such as pentane, hexane, heptane, cyclohexane, aromatic hydrocarbon solvents such as benzene, toluene, xylene, ketone solvents such as acetone, ethyl methyl ketone, diethyl ketone, Alkyl halide solvents such as dichloromethane and chloroform, aromatic aryl halide solvents such as chlorobenzene and dichlorobenzene, dimethylformamide, diethylformamide Amide solvents such as N- methylpyrrolidone, water and mixtures thereof.

  The conjugated block copolymer of the present invention has, as a terminal group, a halogen atom, a trialkyltin group, a boronic acid group, a boronic acid ester group or other coupling residue, or a hydrogen atom from which these atoms or groups are eliminated. It may have a terminal structure in which these terminal groups are further substituted with a terminal blocking agent composed of an aromatic halide such as benzene bromide or an aromatic boronic acid compound.

  The conjugated block copolymer thus obtained can be used as a composition that is an organic semiconductor material that forms an organic thin film by being mixed with a fullerene derivative that is an electron-accepting material. These conjugated block copolymers may be used individually by 1 type in a composition, and may be used in combination of 2 or more type.

  In the composition of the present invention, at least a conjugated block copolymer and a fullerene derivative are mixed in the presence of a solvent. This composition is useful, for example, as a functional layer of a photoelectric conversion element.

  The ratio of the conjugated block copolymer and the fullerene derivative in the composition is preferably 10 to 1000 parts by weight and more preferably 50 to 500 parts by weight with respect to 100 parts by weight of the conjugated block copolymer. preferable.

  In addition to the conjugated block copolymer and fullerene derivative, which are essential components in this composition, contains a third component such as a non-conjugated polymer, a surfactant, a high-boiling solvent such as 1,8-diiodooctane, etc. You may do it. The content of the third component is preferably 30% by mass or less and 10% by mass or less with respect to the total weight of the conjugated block copolymer and the fullerene derivative from the viewpoint of the performance of the photoelectric conversion element. And more preferred.

Specific examples of the fullerene derivative contained in the composition include C ₆₀ , C ₇₀ , C ₈₄ and derivatives thereof. Specific structural examples of the fullerene derivative are shown in the following chemical formulas (a) to (nu).

  The mixing method of the conjugated block copolymer and the fullerene derivative is not particularly limited. As a mixing method of the conjugated block copolymer and the fullerene derivative, for example, after adding to a solvent at a desired ratio, one or a plurality of methods such as heating, stirring and ultrasonic irradiation are combined and dissolved and mixed in the solvent. A method is mentioned.

  The solvent used when mixing the conjugated block copolymer and the fullerene derivative is not particularly limited as long as it is a solvent that can be mostly dissolved. Specific examples of the solvent include ethers such as tetrahydrofuran, halogen solvents such as methylene chloride and chloroform, and aromatic solvents such as benzene, toluene, orthoxylene, chlorobenzene, orthodichlorobenzene and pyridine.

  The composition containing the conjugated block copolymer and the fullerene derivative can form an organic thin film by a known printing method or coating method. Specific film forming methods include spin coating, casting, micro gravure coating, gravure coating, slot die coating, bar coating, roll coating, dip coating, spray coating, screen printing, flexographic printing. Known methods such as a printing method, an offset printing method, an ink jet printing method, a nozzle coating method, and a capillary coating method can be used.

  The obtained organic thin film is useful as an organic transistor or a photoelectric conversion element. The film thickness of the organic thin film containing the conjugated block copolymer is difficult to determine in general depending on the intended use, but is usually 1 nm to 1 μm, preferably 2 nm to 1000 nm, more preferably 5 nm. It is -500 nm, More preferably, it is 20 nm -300 nm. When used as a photoelectric conversion element, if the film thickness is too thin, light is not sufficiently absorbed, and conversely if it is too thick, it becomes difficult for carriers to reach the electrode and high conversion efficiency cannot be obtained.

  An example is given and demonstrated about the photoelectric conversion element using the organic thin film formed into a film from the composition of this invention.

  The photoelectric conversion element of the present invention has an organic photoelectric conversion layer formed by using the conjugated block copolymer of the present invention between at least two different electrodes, that is, a positive electrode and a negative electrode.

  It is preferable that the electrode of a photoelectric conversion element has a light transmittance in either a positive electrode or a negative electrode. The optical transparency of the electrode is not particularly limited as long as incident light reaches the organic photoelectric conversion layer and an electromotive force is generated. The thickness of an electrode should just be the range which has a light transmittance and electroconductivity, and although it changes with electrode materials, 20 nm-300 nm are preferable. Note that in the case where one electrode has light transparency, the light transmission property is not necessarily required as long as the other electrode has conductivity. Furthermore, the thickness of this electrode is not particularly limited.

  As an electrode material, it is preferable to use a conductive material having a high work function for one electrode and a conductive material having a low work function for the other electrode. An electrode using a conductive material having a large work function is a positive electrode. Conductive materials with a large work function include metals such as gold, platinum, chromium and nickel, transparent metal oxides such as indium and tin, composite metal oxides (indium tin oxide (ITO), indium Zinc oxide (IZO), fluorine-doped tin oxide (FTO), etc.) are preferably used. Here, the conductive material used for the positive electrode is preferably an ohmic junction with the organic photoelectric conversion layer. Furthermore, when a hole transport layer described later is used, it is preferable that the conductive material used for the positive electrode is an ohmic contact with the hole transport layer.

  An electrode using a conductive material having a low work function serves as a negative electrode. As the conductive material having a low work function, alkali metal or alkaline earth metal, specifically, lithium, magnesium, or calcium is used. Tin, silver, and aluminum are also preferably used. Furthermore, an electrode made of an alloy made of the above metal or a laminate of the above metal is also preferably used.

  Further, it is possible to improve the extraction current by introducing a metal fluoride such as lithium fluoride or cesium fluoride at the interface between the negative electrode and the electron transport layer described later. Here, the conductive material used for the negative electrode is preferably one that is in ohmic contact with the organic photoelectric conversion layer. Furthermore, when the electron transport layer is used, it is preferable that the conductive material used for the negative electrode is in ohmic contact with the electron transport layer.

  The photoelectric conversion element is usually formed on a base material. This substrate may be any substrate that does not change when the electrode is formed and the organic photoelectric conversion layer is formed. Examples of substrate materials include inorganic materials such as non-alkali glass and quartz glass, metal films such as aluminum, polyester, polycarbonate, polyolefin, polyamide, polyimide, polyphenylene sulfide, polyparaxylene, epoxy resin, fluorine resin, and the like. A film or plate produced from any organic material by any method can be used. If an opaque substrate is used, the opposite electrode, i.e. the electrode far from the substrate, must be transparent or translucent. Although the film thickness of a board | substrate is not specifically limited, Usually, it is the range of 1 micrometer-10 mm.

  Further, in order to improve the wettability of the substrate and the interfacial adhesion between the organic layer having an organic photoelectric conversion layer between the positive electrode or the negative electrode and the substrate, ultraviolet ozone treatment, corona discharge treatment, plasma treatment It is preferable to clean and modify the surface by physical means such as A method of chemically modifying the surface of the solid substrate such as a silane coupling agent, a titanate coupling agent, or a self-assembled monolayer is also effective.

In the photoelectric conversion element, a hole transport layer may be provided between the positive electrode and the organic photoelectric conversion layer as necessary. As a material for forming the hole transport layer, conductive polymers such as polythiophene polymers, poly-p-phenylene vinylene polymers, polyfluorene polymers, phthalocyanine derivatives (H ₂ Pc, CuPc, ZnPc, etc.) ), Low molecular organic compounds exhibiting p-type semiconductor properties such as porphyrin derivatives are preferably used. In particular, polyethylenedioxythiophene (PEDOT) which is a polythiophene polymer or PEDOT to which polystyrene sulfonate (PSS) is added is preferably used. The hole transport layer preferably has a thickness of 5 nm to 600 nm, more preferably 20 nm to 300 nm.

  A photoelectric conversion element may provide an electron carrying layer between a negative electrode and an organic photoelectric conversion layer as needed. As a material for forming the electron transport layer, n-type semiconductor materials such as phenanthrene compounds such as bathocuproine, naphthalenetetracarboxylic acid anhydride, naphthalenetetracarboxylic acid diimide, perylenetetracarboxylic acid anhydride, perylenetetracarboxylic acid diimide, and N-type inorganic oxides such as titanium oxide, zinc oxide, and gallium oxide, and alkali metal compounds such as lithium fluoride, sodium fluoride, and cesium fluoride can be used. A layer made of a single n-type semiconductor material used for the bulk heterojunction layer can also be used.

  The photoelectric conversion element may further have an inorganic layer. Examples of the material contained in the inorganic layer include titanium oxide, tin oxide, zinc oxide, iron oxide, tungsten oxide, zirconium oxide, hafnium oxide, strontium oxide, indium oxide, cerium oxide, yttrium oxide, lanthanum oxide, and vanadium oxide. , Metal oxides such as niobium oxide, tantalum oxide, gallium oxide, nickel oxide, strontium titanate, barium titanate, potassium niobate, sodium tantalate; silver iodide, silver bromide, copper iodide, copper bromide, Metal halides such as lithium fluoride; metals such as zinc sulfide, titanium sulfide, indium sulfide, bismuth sulfide, cadmium sulfide, zirconium sulfide, tantalum sulfide, molybdenum sulfide, silver sulfide, copper sulfide, tin sulfide, tungsten sulfide, and antimony sulfide Sulfide; Cadmium selenide Metal selenides such as zirconium selenide, zinc selenide, titanium selenide, indium selenide, tungsten selenide, molybdenum selenide, bismuth selenide, lead selenide; cadmium telluride, tungsten telluride, molybdenum telluride, tellurium Metal tellurides such as zinc phosphide and bismuth telluride; metal phosphides such as zinc phosphide, gallium phosphide, indium phosphide and cadmium phosphide; gallium arsenide, copper-indium selenide, copper-indium sulfide, Examples thereof include silicon and germanium, and a mixture of two or more of these may be used. Examples of the mixture include a mixture of zinc oxide and tin oxide, a mixture of tin oxide and titanium oxide, and the like.

  The photoelectric conversion element of this invention is obtained by the following manufacturing processes, for example. A composition prepared from a conjugated block copolymer and an electron-accepting material is formed on a substrate on which a positive electrode is formed on a glass by using the above-described film forming method, and then dried to form an organic material. A photoelectric conversion layer is formed. A photoelectric conversion element can be manufactured by forming the electrode used as a negative electrode on this organic photoelectric converting layer.

  The photoelectric conversion element of the present invention can be applied to various photoelectric conversion devices using a photoelectric conversion function, an optical rectification function (photo diode), and the like. For example, it is useful for optical recording materials such as photovoltaic cells such as solar cells, optical sensors, optical switches, electronic devices such as phototransistors, and optical memories.

  Examples of the present invention will be described in detail below, but the scope of the present invention is not limited to these examples.

  Synthesis examples of conjugated polymer blocks constituting the conjugated block copolymer are shown in Polymerization Examples 1 to 8, and synthesis of the conjugated block copolymer of the present invention using the same is shown in Examples 1 to 8. Comparative examples 1 to 9 show the non-application of the present invention.

(Polymerization example 1)
The conjugated polymer block A1 was synthesized according to the following reaction formula (1). In the following reaction formula, ethylhexyl as a substituent is abbreviated as EtHex or HexEt.

In a 100 mL three-necked flask under a nitrogen atmosphere, 2,6-dibromo-4,4′-bis (2-ethylhexyl) -cyclopenta [2,1-b: 3,4-b ′] dithiophene (1.50 g, 2.68 mmol). ), 4,7-bis (3,3,4,4-tetramethyl-2,5,1-dioxaborolan-1-yl) benzo [c] [1,2,5] thiadiazole (1.04 g, 2. 68 mmol), toluene (50 mL), 2M aqueous potassium carbonate solution (25 mL, 50 mmol), tetrakis (triphenylphosphine) palladium (0) (Pd (PPh ₃ ) ₄ ) (61.9 mg, 53.5 μmol), aliquat 336 (2 mg, 4.95 μmol) was added, followed by stirring at 80 ° C. for 2 hours. Thereafter, phenylboronic acid pinacol ester (273 mg, 1.34 mmol) was added, and the mixture was stirred at 80 ° C. for 18 hours. After completion of the reaction, the reaction solution was poured into methanol (500 mL), the precipitated solid was collected by filtration, washed with water (100 mL) and methanol (100 mL), and the resulting solid was dried under reduced pressure to obtain a crude product. It was. The crude product was washed with acetone (200 mL) and hexane (200 mL) using a Soxhlet extractor and then extracted with chloroform (200 mL). The obtained solution was poured into methanol (2 L), and the precipitated solid was collected by filtration and dried under reduced pressure to obtain a conjugated polymer block A1 as a black purple solid (1.04 g, 41%).

The obtained conjugated polymer block A1 was subjected to physicochemical analysis.
^The molecular structure was identified by ¹ H-NMR (nuclear magnetic resonance) measurement.
¹ H-NMR (270 MHz): δ = 8.10-7.95 (m, 2H), 7.80-7.61 (m, 2H), 2.35-2.12 (m, 4H), 1 .60-1.32 (m, 18H), 1.18-0.82 (m, 12H)
The number average molecular weight (Mn) and the weight average molecular weight (Mw) were both determined in terms of polystyrene based on measurement by gel permeation chromatography (GPC). Here, HLC-8320GPC manufactured by Tosoh Corporation was used as the GPC apparatus, and TSKgel SuperMultipore HZ-M manufactured by Tosoh Corporation was connected in series as the column. Using the values of the number average molecular weight (Mn) and the weight average molecular weight (Mw), the dispersity (PDI) was determined by (Mw) / (Mn).
GPC (CHCl ₃ ): Mn = 19600 g / mol, Mw = 45500 g / mol, PDI = 2.32
This physicochemical analysis result supports the chemical structure shown in the reaction formula (1).

(Polymerization example 2)
The conjugated polymer block A2 was synthesized according to the following reaction formula (2).

  In a 100 mL three-necked flask under a nitrogen atmosphere, 2,6-dibromo-4,4′-bis (2-ethylhexyl) -dithieno [3,2-b: 2 ′, 3′-d] germole (1.66 g, 2. 68 mmol), 4,7-bis (3,3,4,4-tetramethyl-2,5,1-dioxaborolan-1-yl) benzo [c] [1,2,5] thiadiazole (1.04 g, 2 .68 mmol), toluene (50 mL), 2M aqueous potassium carbonate solution (25 mL, 50 mmol), tetrakis (triphenylphosphine) palladium (0) (61.9 mg, 53.5 μmol), aliquat 336 (2 mg, 4.95 μmol) were added. Thereafter, the mixture was stirred at 80 ° C. for 2 hours. Thereafter, phenylboronic acid pinacol ester (273 mg, 1.34 mmol) was added, and the mixture was stirred at 80 ° C. for 18 hours. After completion of the reaction, the reaction solution was poured into methanol (500 mL), the precipitated solid was collected by filtration, washed with water (100 mL) and methanol (100 mL), and the resulting solid was dried under reduced pressure to obtain a crude product. It was. The crude product was washed with acetone (200 mL) and hexane (200 mL) using a Soxhlet extractor and then extracted with chloroform (200 mL). The obtained solution was poured into methanol (2 L), and the precipitated solid was collected by filtration and dried under reduced pressure to obtain a conjugated polymer block A2 as a black purple solid (1.03 g, 38%).

In the same manner as in Polymerization Example 1, the obtained conjugated polymer block A2 was subjected to physicochemical analysis.
¹ H-NMR (270 MHz), δ = 8.20-7.95 (m, 2H), 7.90-7.12 (m, 2H), 2.34-2.10 (m, 4H), 1 .59-1.33 (m, 18H), 1.19-0.81 (m, 12H)
GPC (CHCl ₃ ): Mn = 17500 g / mol, Mw = 42400 g / mol, PDI = 2.42
This physicochemical analysis result supports the chemical structure shown in the reaction formula (2).

(Polymerization Example 3)
The conjugated polymer block A3 was synthesized according to the following reaction formula (3).

  To an eggplant flask A thoroughly dried and purged with argon, 25 mL of tetrahydrofuran (THF) subjected to dehydration and peroxide removal treatment, 1.865 g (5 mmol) of 2-bromo-5-iodo-3-hexylthiophene, Then, 2.5 mL of a 2.0M solution of i-propylmagnesium chloride was added and stirred at 0 ° C. for 30 minutes to synthesize an organomagnesium compound solution represented by the chemical formula (a1) in the above reaction formula.

To the dried argon-substituted eggplant flask B, 25 mL of THF and 27 mg (0.05 mmol) of dehydrated and peroxide-removed treatment and 27 mg (0.05 mmol) of NiCl ₂ (dppp) were added and heated to 35 ° C. Then, the organic magnesium compound solution (a1 ) Was added. After stirring with heating at 35 ° C. for 1.5 hours, 50 mL of 5M hydrochloric acid was added and stirred at room temperature for 1 hour. This reaction solution was extracted with 450 mL of chloroform, and the organic layer was washed with 100 mL of sodium bicarbonate water and 100 mL of distilled water in this order. The organic layer was dried over anhydrous sodium sulfate and concentrated to dryness. The obtained black-purple solid was dissolved in 30 mL of chloroform, reprecipitated into 300 mL of methanol, and sufficiently dried, and purified using a preparative GPC column to give a conjugated polymer block A3 ( 690 mg) was obtained.

  In addition, THF as a solvent was purified by distillation of dehydrated tetrahydrofuran (without stabilizer) manufactured by Wako Pure Chemical Industries, Ltd. in the presence of metallic sodium, and then on molecular sieves 5A manufactured by Wako Pure Chemical Industries, Ltd. for one day or more. Purification was carried out by contact. The polymer was purified using a preparative GPC column. The apparatus used was Recycling Preparative HPLC LC-908 manufactured by Japan Analytical Industry. In addition, the kind of column connects the two styrene polymer columns 2H-40 and 2.5H-40 by Nippon Analytical Industry in series. Further, chloroform was used as an elution solvent.

In the same manner as in Polymerization Example 1, the obtained conjugated polymer block A3 was subjected to physicochemical analysis.
¹ H-NMR: δ = 6.97 (s, 1H), 2.80 (t, J = 8.0 Hz, 2H), 1.89-1.27 (m, 10H), 0.91 (t, J = 6.8Hz, 3H)
GPC (CHCl ₃ ): Mn = 21000 g / mol, Mw = 24150 g / mol, PDI = 1.15
This physicochemical analysis result supports the chemical structure shown in the reaction formula (3).

Example 1
The conjugated block copolymer 1 was synthesized according to the following reaction formula (4). In the structural formulas or reaction formulas of the conjugated block copolymers in the following examples, “-b-” indicates block copolymerization, and “-r-” or “-ran-” indicates random copolymerization. .

  Under a nitrogen atmosphere, a conjugated polymer block A1 (0.80 g), a conjugated polymer block A3 (0.80 g), toluene (20 mL), a 2M aqueous potassium carbonate solution (10 mL, 20 mmol), tetrakis (triphenylphosphine) in a 100 mL three-necked flask. ) Palladium (0) (20.5 mg, 17.7 μmol) and aliquat 336 (0.8 mg, 1.98 μmol) were added, followed by stirring at 80 ° C. for 24 hours. After completion of the reaction, the reaction solution was poured into methanol (200 mL), the precipitated solid was collected by filtration, washed with water (20 mL) and methanol (20 mL), and the resulting solid was dried under reduced pressure to obtain a crude product. It was. The crude product was washed with acetone (100 mL) and hexane (100 mL) using a Soxhlet extractor, and then extracted with chloroform (100 mL). The obtained solution was poured into methanol (1 L), and the precipitated solid was collected by filtration and dried under reduced pressure to obtain a conjugated block copolymer 1 as a black purple solid (0.53 g, 33%).

In the same manner as in Polymerization Example 1, the obtained conjugated block copolymer 1 was subjected to physicochemical analysis.
¹ H-NMR (270 MHz): δ = 8.12-7.94 (m, 2H), 7.80-7.61 (m, 2H), 6.97 (s, 1H) 2.35-2. 12 (m, 6H), 1.62-1.31 (m, 26H), 1.19-0.83 (m, 15H)
GPC (CHCl ₃ ): Mn = 41000 g / mol, Mw = 86100 g / mol, PDI = 2.10
This physicochemical analysis result supports the chemical structure shown in the reaction formula (4).

(Example 2)
The conjugated block copolymer 2 was synthesized according to the following reaction formula (5).

  Under a nitrogen atmosphere, a conjugated polymer block A2 (0.80 g), a conjugated polymer block A3 (0.80 g), toluene (20 mL), a 2M aqueous potassium carbonate solution (10 mL, 20 mmol), tetrakis (triphenylphosphine) in a 100 mL three-necked flask. ) Palladium (0) (20.5 mg, 17.7 μmol) and aliquat 336 (0.8 mg, 1.98 μmol) were added, followed by stirring at 80 ° C. for 24 hours. After completion of the reaction, the reaction solution was poured into methanol (200 mL), the precipitated solid was collected by filtration, washed with water (20 mL) and methanol (20 mL), and the resulting solid was dried under reduced pressure to obtain a crude product. It was. The crude product was washed with acetone (100 mL) and hexane (100 mL) using a Soxhlet extractor, and then extracted with chloroform (100 mL). The obtained solution was poured into methanol (1 L), and the precipitated solid was collected by filtration and dried under reduced pressure to obtain a conjugated block copolymer 2 as a black purple solid (0.53 g, 33%).

In the same manner as in Polymerization Example 1, the obtained conjugated block copolymer 2 was subjected to physicochemical analysis.
¹ H-NMR (270 MHz): δ = 8.21-7.94 (m, 2H), 7.92-7.13 (m, 2H), 6.97 (s, 1H), 2.35-2 .11 (m, 6H), 1.61-1.31 (m, 26H), 1.19-0.83 (m, 15H)
GPC (CHCl ₃ ): Mn = 41000 g / mol, Mw = 86100 g / mol, PDI = 2.10
This physicochemical analysis result supports the chemical structure shown in the reaction formula (5).

(Polymerization example 4)
The conjugated polymer block A4 was synthesized according to the following reaction formula (6).

  In a 100 mL three-necked flask under a nitrogen atmosphere, 2,6-dibromo-4,4′-bis (2-ethylhexyl) -cyclopenta [2,1-b: 3,4-b ′] dithiophene (1.50 g, 2.68 mmol). ), 4,7-bis (3,3,4,4-tetramethyl-2,5,1-dioxaborolan-1-yl) benzo [c] [1,2,5] thiadiazole (1.04 g, 2. 68 mmol), toluene (50 mL), 2M aqueous potassium carbonate solution (25 mL, 50 mmol), tetrakis (triphenylphosphine) palladium (0) (61.9 mg, 53.5 μmol), and aliquat 336 (2 mg, 4.95 μmol). Stir at 80 ° C. for 2 hours. Thereafter, phenyl bromide (210 mg, 1.34 mmol) was added, and the mixture was stirred at 80 ° C. for 18 hours. After completion of the reaction, the reaction solution was poured into methanol (500 mL), the precipitated solid was collected by filtration, washed with water (100 mL) and methanol (100 mL), and the resulting solid was dried under reduced pressure to obtain a crude product. It was. The crude product was washed with acetone (200 mL) and hexane (200 mL) using a Soxhlet extractor and then extracted with chloroform (200 mL). The obtained solution was poured into methanol (2 L), and the precipitated solid was collected by filtration and dried under reduced pressure to obtain a conjugated polymer block A4 as a black purple solid (1.06, 42%).

In the same manner as in Polymerization Example 1, the obtained conjugated polymer block A4 was subjected to physicochemical analysis.
¹ H-NMR (270 MHz): δ = 8.10-7.96 (m, 2H), 7.81-7.61 (m, 2H), 2.35-2.13 (m, 4H), 1 .59-1.32 (m, 18H), 1.18-0.81 (m, 12H)
GPC (CHCl ₃ ): Mn = 20100 g / mol, Mw = 44300 g / mol, PDI = 2.20
This physicochemical analysis result supports the chemical structure shown in the reaction formula (6).

(Polymerization Example 5)
The conjugated polymer block A5 was synthesized according to the following reaction formula (7).

  In a 100 mL three-necked flask under a nitrogen atmosphere, 2,6-dibromo-4,4′-dihexadecylcyclopenta [2,1-b: 3,4-b ′] dithiophene (2.05 g, 2.68 mmol), 4 , 7-bis (3,3,4,4-tetramethyl-2,5,1-dioxaborolan-1-yl) benzo [c] [1,2,5] thiadiazole (1.04 g, 2.68 mmol), Toluene (50 mL), 2M aqueous potassium carbonate solution (25 mL, 50 mmol), tetrakis (triphenylphosphine) palladium (0) (61.9 mg, 53.5 μmol), and aliquat 336 (2 mg, 4.95 μmol) were added at 80 ° C. Stir for 2 hours. Thereafter, phenylboronic acid pinacol ester (273 mg, 1.34 mmol) was added, and the mixture was stirred at 80 ° C. for 18 hours. After completion of the reaction, the reaction solution was poured into methanol (500 mL), the precipitated solid was collected by filtration, washed with water (100 mL) and methanol (100 mL), and the resulting solid was dried under reduced pressure to obtain a crude product. It was. The crude product was washed with acetone (200 mL) and hexane (200 mL) using a Soxhlet extractor and then extracted with chloroform (200 mL). The obtained solution was poured into methanol (2 L), and the precipitated solid was collected by filtration and then dried under reduced pressure to obtain a conjugated polymer block A5 as a black purple solid (1.11 g, 36%).

In the same manner as in Polymerization Example 1, physicochemical analysis of the resulting conjugated polymer block A5 was performed.
¹ H-NMR (270 MHz): δ = 8.13-7.95 (m, 2H), 7.82-7.35 (m, 2H), 3.04-2.89 (m, 4H), 2 .34-2.13 (m, 8H), 1.55-1.42 (m, 12H), 1.35-1.09 (m, 36H), 0.82 (m, 6H)
GPC (CHCl ₃ ): Mn = 18900 g / mol, Mw = 37200 g / mol, PDI = 1.97
This physicochemical analysis result supports the chemical structure shown in the reaction formula (7).

(Polymerization Example 6)
The conjugated polymer block A6 was synthesized according to the following reaction formula (8).

  In a 100 mL three-necked flask under a nitrogen atmosphere, 2,6-dibromo-4,4′-bis (4,4,5,5,6,6,7,7,7-nonafluoroheptyl) -cyclopenta [2,1- b: 3,4-b ′] dithiophene (2.29 g, 2.68 mmol), 4,7-bis (3,3,4,4-tetramethyl-2,5,1-dioxaborolan-1-yl) benzo [C] [1,2,5] thiadiazole (1.04 g, 2.68 mmol), toluene (50 mL), 2M aqueous potassium carbonate solution (25 mL, 50 mmol), tetrakis (triphenylphosphine) palladium (0) (61.9 mg) , 53.5 μmol) and aliquat 336 (2 mg, 4.95 μmol) were added, followed by stirring at 80 ° C. for 2 hours. Thereafter, phenylboronic acid pinacol ester (273 mg, 1.34 mmol) was added, and the mixture was stirred at 80 ° C. for 18 hours. After completion of the reaction, the reaction solution was poured into methanol (500 mL), the precipitated solid was collected by filtration, washed with water (100 mL) and methanol (100 mL), and the resulting solid was dried under reduced pressure to obtain a crude product. It was. The crude product was washed with acetone (200 mL) and hexane (200 mL) using a Soxhlet extractor and then extracted with chloroform (200 mL). The obtained solution was poured into methanol (2 L), and the precipitated solid was collected by filtration and dried under reduced pressure to obtain conjugated polymer block A6 as a black purple solid (1.20 g, 43%).

In the same manner as in Polymerization Example 1, physicochemical analysis of the resulting conjugated polymer block A6 was performed.
¹ H-NMR (270 MHz): δ = 8.12-7.97 (m, 2H), 7.90-7.32 (m, 2H), 2.75 (t, J = 7.56 Hz, 4H) 2.31-1.92 (m, 8H)
GPC (CHCl ₃ ): Mn = 1920 g / mol, Mw = 42700 g / mol, PDI = 2.22
This physicochemical analysis result supports the chemical structure shown in the reaction formula (8).

(Polymerization Example 7)
The conjugated polymer block A7 was synthesized according to the following reaction formula (9).

  Under a nitrogen atmosphere, 2,6-dibromo-4,4′-bis (6,6,6-trifluorohexyl) -cyclopenta [2,1-b: 3,4-b ′] dithiophene (1 .64 g, 2.68 mmol), 4,7-bis (3,3,4,4-tetramethyl-2,5,1-dioxaborolan-1-yl) benzo [c] [1,2,5] thiadiazole ( 1.04 g, 2.68 mmol), toluene (50 mL), 2M aqueous potassium carbonate (25 mL, 50 mmol), tetrakis (triphenylphosphine) palladium (0) (61.9 mg, 53.5 μmol), aliquat 336 (2 mg, 4. (95 μmol), and the mixture was stirred at 80 ° C. for 2 hours. Thereafter, phenylboronic acid pinacol ester (273 mg, 1.34 mmol) was added, and the mixture was stirred at 80 ° C. for 18 hours. After completion of the reaction, the reaction solution was poured into methanol (500 mL), the precipitated solid was collected by filtration, washed with water (100 mL) and methanol (100 mL), and the resulting solid was dried under reduced pressure to obtain a crude product. It was. The crude product was washed with acetone (200 mL) and hexane (200 mL) using a Soxhlet extractor and then extracted with chloroform (200 mL). The obtained solution was poured into methanol (2 L), and the precipitated solid was collected by filtration and dried under reduced pressure to obtain a conjugated polymer block A7 as a black purple solid (1.18 g, 44%).

In the same manner as in Polymerization Example 1, the obtained conjugated polymer block A7 was subjected to physicochemical analysis.
¹ H-NMR (270 MHz): δ = 8.12-7.97 (m, 2H), 7.90-7.32 (m, 2H), 2.75 (t, J = 7.56 Hz, 4H) 2.31-1.92 (m, 16H)
GPC (CHCl ₃ ): Mn = 20600 g / mol, Mw = 46000 g / mol, PDI = 2.23
This physicochemical analysis result supports the chemical structure shown in the reaction formula (9).

(Example 3)
The conjugated block copolymer 3 was synthesized according to the following reaction formula (10).

  Under a nitrogen atmosphere, a conjugated polymer block A4 (0.80 g), a conjugated polymer block A5 (0.80 g), toluene (20 mL), a 2M aqueous potassium carbonate solution (10 mL, 20 mmol), tetrakis (triphenylphosphine) in a 100 mL three-necked flask. ) Palladium (0) (20.5 mg, 17.7 μmol) and aliquat 336 (0.8 mg, 1.98 μmol) were added, followed by stirring at 80 ° C. for 24 hours. After completion of the reaction, the reaction solution was poured into methanol (200 mL), the precipitated solid was collected by filtration, washed with water (20 mL) and methanol (20 mL), and the resulting solid was dried under reduced pressure to obtain a crude product. It was. The crude product was washed with acetone (100 mL) and hexane (100 mL) using a Soxhlet extractor, and then extracted with chloroform (100 mL). The obtained solution was poured into methanol (1 L), and the precipitated solid was collected by filtration and dried under reduced pressure to obtain a conjugated block copolymer 3 as a black purple solid (0.58 g, 36%).

In the same manner as in Polymerization Example 1, the obtained conjugated block copolymer 3 was subjected to physicochemical analysis.
¹ H-NMR (270 MHz): δ = 8.13-7.94 (m, 4H), 7.82-7.35 (m, 4H), 3.04-2.90 (m, 4H) 35-2.12 (m, 12H), 1.60-1.30 (m, 30H), 1.35-1.20 (m, 36H), 1.18-0.82 (m, 18H)
GPC (CHCl ₃ ): Mn = 39600 g / mol, Mw = 83700 g / mol, PDI = 2.11
This physicochemical analysis result supports the chemical structure shown in the reaction formula (10).

Example 4
The conjugated block copolymer 4 was synthesized according to the following reaction formula (11).

  Under a nitrogen atmosphere, a polymer block A4 (0.80 g) and a polymer represented by the polymer block A6 (0.80 g), toluene (20 mL), 2M aqueous potassium carbonate solution (10 mL, 20 mmol), tetrakis (tri Phenylphosphine) palladium (0) (20.5 mg, 17.7 μmol) and aliquat 336 (0.8 mg, 1.98 μmol) were added, followed by stirring at 80 ° C. for 24 hours. After completion of the reaction, the reaction solution was poured into methanol (200 mL), the precipitated solid was collected by filtration, washed with water (20 mL) and methanol (20 mL), and the resulting solid was dried under reduced pressure to obtain a crude product. It was. The crude product was washed with acetone (100 mL) and hexane (100 mL) using a Soxhlet extractor, and then extracted with chloroform (100 mL). The obtained solution was poured into methanol (1 L), and the precipitated solid was collected by filtration and dried under reduced pressure to obtain a conjugated block copolymer 4 as a black purple solid (0.67 g, 42%).

In the same manner as in Polymerization Example 1, the obtained conjugated block copolymer 4 was subjected to physicochemical analysis.
¹ H-NMR (270 MHz): δ = 8.12-7.96 (m, 4H), 7.85-7.32 (m, 4H), 2.74 (t, J = 7.58 Hz, 4H) 2.35-1.31 (m, 30H), 1.19-0.82 (m, 12H)
GPC (CHCl ₃ ): Mn = 40200 g / mol, Mw = 86100 g / mol, PDI = 2.14
This physicochemical analysis result supports the chemical structure shown in the reaction formula (11).

(Example 5)
The conjugated block copolymer 5 was synthesized according to the following reaction formula (12).

  To a eggplant flask A thoroughly dried and purged with argon, 20 mL of THF subjected to dehydration and peroxide removal treatment, 1.512 g (4.05 mmol) of 2-bromo-5-iodo-3-hexylthiophene, i, 2 mL of a 2.0M solution of propylmagnesium chloride was added and stirred at 0 ° C. for 30 minutes to synthesize an organic magnesium compound solution (a1-1). In another eggplant flask B that had been thoroughly dried and replaced with argon, 5 mL of THF and 2,5-dibromo-3- [6- (2-tetrahydropyranyl) oxyhexyl] thiophene subjected to dehydration and peroxide removal treatment 403 g (0.95 mmol) and 0.95 mL of a 1.0M solution of t-butylmagnesium chloride were added and stirred at 60 ° C. for 2 hours to synthesize an organic magnesium compound solution (a1-2).

To an eggplant flask C sufficiently dried and purged with argon, 25 mL of THF and 27 mg (0.05 mmol) of dehydrated and peroxide-removed treatment and 27 mg (0.05 mmol) of NiCl ₂ (dppp) were added and heated to 35 ° C. 70% of the organomagnesium compound solution (a1-1) was added, and the mixture was heated and stirred at 35 ° C. for 1.5 hours. Subsequently, the remaining organomagnesium compound solution (a1-1) and organomagnesium compound solution (a1-2) were added and reacted at 35 ° C. for 2 hours. After completion of the reaction, 1.0M of t-butylmagnesium chloride
2 mL of THF solution was added and stirred at 35 ° C. for 1 hour, and then 30 mL of 5M hydrochloric acid was added and stirred at room temperature for 1 hour. This reaction solution was extracted with 450 mL of chloroform, and the organic layer was washed with 100 mL of sodium bicarbonate water and 100 mL of distilled water in this order. The organic layer was dried over anhydrous sodium sulfate and concentrated to dryness. By dissolving the obtained black-purple solid in 30 mL of chloroform, reprecipitating it in 300 mL of methanol, and thoroughly drying it using a preparative GPC column in the same manner as in Polymerization Example 3 Conjugated block copolymer 5 (650 mg) was obtained.

The number average molecular weight (Mn), weight average molecular weight (Mw), and dispersity (PDI) of the conjugated block copolymer 5 obtained were determined in the same manner as in Polymerization Example 1.
GPC (CHCl ₃ ): Mn = 20,800, Mw = 23,400, PDI = 1.13

(Example 6)
The conjugated block copolymer 6 was synthesized according to the following reaction formula (13).

To a eggplant flask A thoroughly dried and purged with argon, 21 mL of THF subjected to dehydration and peroxide removal treatment, 1.573 g (4.2 mmol) of 2-bromo-5-iodo-3-hexylthiophene, i, -2.1 mL of a 2.0M solution of propylmagnesium chloride was added and stirred at 0 ° C for 30 minutes to synthesize an organic magnesium compound solution (a2-1). In another eggplant flask B that had been thoroughly dried and purged with argon, 4 mL of THF subjected to dehydration and peroxide removal treatment and 0.393 g of 2,5-dibromo-3- (6,6,6-trifluorohexyl) thiophene ( 0.8 mmol) and 0.8 mL of a 1.0M solution of t-butylmagnesium chloride were added and stirred at 60 ° C. for 2 hours to synthesize an organomagnesium compound solution (a2-2).
To an eggplant flask C sufficiently dried and purged with argon, 25 mL of THF and 27 mg (0.05 mmol) of dehydrated and peroxide-removed treatment and 27 mg (0.05 mmol) of NiCl ₂ (dppp) were added and heated to 35 ° C. The organomagnesium compound solution (a2-1) was added, and the mixture was stirred with heating at 35 ° C. for 1.5 hours. Next, an organomagnesium compound solution (a2-2) was added and reacted at 35 ° C. for 2 hours. After completion of the reaction, 1.0M of t-butylmagnesium chloride
2 mL of THF solution was added and stirred at 35 ° C. for 1 hour, and then 30 mL of 5M hydrochloric acid was added and stirred at room temperature for 1 hour. This reaction solution was extracted with 450 mL of chloroform, and the organic layer was washed with 100 mL of sodium bicarbonate water and 100 mL of distilled water in this order. The organic layer was dried over anhydrous sodium sulfate and concentrated to dryness. By dissolving the obtained black-purple solid in 30 mL of chloroform, reprecipitating it in 300 mL of methanol, and thoroughly drying it using a preparative GPC column in the same manner as in Polymerization Example 3 Conjugated block copolymer 6 (699 mg) was obtained.

The number average molecular weight (Mn), weight average molecular weight (Mw), and dispersity (PDI) of the conjugated block copolymer 6 obtained were determined in the same manner as in Polymerization Example 1.
GPC (CHCl ₃ ): Mn = 21,100, Mw = 25,100, PDI = 1.19
(Polymerization Example 8)
The conjugated polymer block A8 was synthesized according to the following reaction formula (14). In the following reaction formulas, 3-heptyl as a substituent is abbreviated as 3-Hep or Hep-3. In the following reaction formulas, methyl as a substituent is abbreviated as Me.

  Under a nitrogen atmosphere, 2,6-bis (trimethyltin) -4,8-didodecylbenzo [1,2-b: 4,5-, which is a monomer constituting conjugated polymer block A8, in a 50 ml eggplant flask b ′] dithiophene (0.64 g, 0.75 mmol) and 1- (4,6-dibromothieno [3,4-b] thiophen-2-yl) -2-ethylhexane-1-one (0.32 g, 0 .75 mmol), DMF (6.2 mL), toluene (25 mL), tetrakis (triphenylphosphine) palladium (0) (9.2 mg, 7.8 μmol) were added, and the mixture was heated at 115 ° C. for 1 hour 30 minutes. Next, 2,5-dibromothiophene (1.84 g, 7.6 mmol) was added as a linker compound and heated at 115 ° C. for 16 hours. After completion of the reaction, the reaction solution was concentrated, poured into methanol (500 mL), the precipitated solid was collected by filtration, and the obtained solid was dried under reduced pressure to obtain a crude product. The crude product was washed with acetone (200 ml) and hexane (200 mL) using a Soxhlet extractor and then extracted with chloroform (200 mL). The organic layer was concentrated to dryness, and the resulting black purple solid was dissolved in chloroform (30 mL) and reprecipitated with methanol (300 mL).

  Purification of the resulting conjugated polymer A8 was performed using a preparative GPC column. As a device for purification, Recycling Preparative HPLC LC-908 manufactured by Japan Analytical Industry Co., Ltd. was used. In addition, the kind of column connects two styrene-type polymer columns 2H-40 and 2.5H-40 by Nippon Analysis Industry Co., Ltd. in series. The column and injector were 145 ° C., and the elution solvent was chloroform.

The number average molecular weight (Mn) and the weight average molecular weight (Mw) were both determined in terms of polystyrene based on measurement by gel permeation chromatography (GPC).
Here, GPC / V2000 manufactured by Waters was used as the GPC device, and a Shodex AT-G806MS manufactured by Showa Denko was connected in series as the column. The column and injector were 145 ° C., and o-dichlorobenzene was used as an elution solvent.

The resulting conjugated polymer block A8 (0.51 g, 86%) had a weight average molecular weight (Mw) of 33,100, a number average molecular weight (Mn) of 14,600, and a polydispersity of 2.27.
1H NMR (270 MHz, CDCl3): δ = 7.60-7.30 (br, 3H), 3.30-3.00 (Br, 5H), 2.00-1.10 (br, 52H), 1 .00-0.70 (br, 12H)
(Example 7)
The conjugated block copolymer 7 was synthesized according to the following reaction formula (15).

Under an argon atmosphere, conjugated polymer block A8 (160.0 mg, 0.12 mol) and 2,6-bis (trimethyltin) -4,8-bis ( 2-Ethylhexyloxy) benzo [1,2-b: 4,5-b ′] dithiophene (113.0 mg, 0.16 mmol), 2,6-bis (trimethyltin) -4,8-dipropylbenzo [1 , 2-b: 4,5-b ′] dithiophene (40.9 mg, 0.07 mmol) and 1- (4,6-dibromothieno [3,4-b] thiophen-2-yl) -2-ethylhexane- 1-one (86.0 mg, 0.20 mmol) was added, DMF (0.3 mL), toluene (1.4 mL), tetrakis (triphenylphosphine) palladium (0) (3.4 mg). 2.98Myumol) were added and the vessel was bubbled 20 minutes with argon gas, and heated at 110 ° C. 10 hours. After completion of the reaction, the reaction solution was poured into methanol (500 mL), the precipitated solid was collected by filtration, and the obtained solid was dried under reduced pressure to obtain a crude product. The crude product was washed with acetone (200 mL) and hexane (200 mL) using a Soxhlet extractor and then extracted with chloroform (200 mL). The obtained solution was poured into methanol (300 mL), and the precipitated solid was collected by filtration and dried under reduced pressure to obtain conjugated block copolymer 7 (221.0 mg, 75.4%) as a black purple solid. The obtained conjugated block copolymer 7 was purified by the same method and conditions as in Polymerization Example 8.
The obtained conjugated block copolymer 7 was subjected to physicochemical analysis under the same method and conditions as in Polymerization Example 8. The following physicochemical analysis results support the chemical structure shown in the above reaction formula.
¹ H-NMR (270 MHz, CDCl ₃ ): δ = 7.60-7.30 (br, 3H), 4.40-4.00 (br, 4H), 3.30-3.00 (Br, 4H) ), 2.00-0.60 (br, 51H)
GPC (CHCl ₃ ): Mn = 28800 g / mol, Mw = 86400 g / mol, PDI = 2.99
(Example 8)
The conjugated block copolymer 8 was synthesized according to the following reaction formula (16).

  Conjugated polymer block A8 (0.59 g, 0.75 mmol), 2,6-bis (trimethyltin) -4,8-bis (5- (2-ethylhexyl) thiophene as a monomer constituting polymer block B 2-yl) benzo [1,2-b: 4,5-b ′] dithiophene (0.68 g, 0.75 mmol) and 1- (4,6-dibromothieno [3,4-b] thiophen-2-yl ) Conjugated block copolymer 8 was obtained using the same method as in Example 7 except that 2-ethylhexane-1-one (0.32 g, 0.75 mmol) was used (0.48 g, 76%). ).

The obtained conjugated block copolymer 8 was subjected to physicochemical analysis in the same manner and under the same conditions as in Polymerization Example 8. The following physicochemical analysis results support the chemical structure shown in the above reaction formula.
1H-NMR (270 MHz, CDCl ₃ ): δ = 7.60-7.30 (br, 8H), 6.95-6.85 (br, 2H), 3.30-3.00 (br, 6H) 2.85-2.75 (Br, 4H), 2.00-0.60 (br, 104H)
GPC (CHCl ₃ ): Mn = 27,500 g / mol, Mw = 67,600 g / mol, PDI = 2.46

(Comparative Example 1)
The glass eggplant flask A that had been sufficiently dried was sufficiently purged with argon, and then 45 parts by mass of THF and 0.054 parts by mass of NiCl 2 (dppp) as a polymerization catalyst were added. In another dried eggplant flask B, 29 parts by mass of THF, 2.8 parts by mass of 2-bromo-5-iodo-3-hexylthiophene, and 3.5 parts by mass of a 2.0 M solution of i-propylmagnesium bromide were added. In addition, the mixture was stirred at 0 degree for 30 minutes. Thereafter, the reaction solution was added to eggplant flask A, and polymerization was carried out at 35 ° C. for 90 minutes. Thereafter, in another dried eggplant flask C, 16 parts by mass of THF, 1.4 parts by mass of 2-bromo-5-iodo-3- (2-ethyl) hexylthiophene, and a 2.0 M solution of i-propylmagnesium bromide The solution which added 1.7 mass parts and was made to react at 0 degreeC for 30 minutes was added to the eggplant flask A, and it reacted for 7 hours. After the reaction, 4 parts by mass of 1.0M THF solution of t-butylmagnesium chloride was added and stirred for 1 hour, and further 100 parts by mass of 5M hydrochloric acid was added and stirred for 1 hour to terminate the polymerization. Thereafter, the mixture was extracted with 900 parts by mass of chloroform, washed with 200 parts by mass of sodium bicarbonate water and 200 parts by mass of distilled water, and concentrated to dryness. The obtained black-purple solid was dissolved in 56 parts by mass of chloroform, reprecipitated in 600 parts by mass of acetone, sufficiently dried, and conjugated block copolymer C1 [Polymer name: poly (3-hexylthiophene-block] -3- (2-Ethylhexyl) thiophene)] (P1).

  According to the same GPC measurement as in Polymerization Example 1, the obtained conjugated block copolymer C1 had a weight average molecular weight of 21,600 and a number average molecular weight of 17,900. The content of the poly (3-hexylthiophene) block was 79 mol%.

(Comparative Example 2)
A conjugated block copolymer C2 was synthesized according to the following reaction formula (17).

  To a eggplant flask A thoroughly dried and purged with argon, 21 mL of THF subjected to dehydration and peroxide removal treatment, 1.573 g (4.2 mmol) of 2-bromo-5-iodo-3-hexylthiophene, i, -2.1 mL of 2.0M solution of propylmagnesium chloride was added and stirred at 0 ° C for 30 minutes to synthesize an organic magnesium compound solution (a3-1). In another eggplant flask B that had been thoroughly dried and replaced with argon, 4 mL of THF and 2,5-dibromo-3- (4,4,5,5,6,6,7,7) were subjected to dehydration and peroxide removal treatment. , 7-Nonafluoroheptyl) thiophene 0.393 g (0.8 mmol) and 1.0 M solution of t-butylmagnesium chloride 0.8 mL were added, and the mixture was stirred at 60 ° C. for 2 hours to obtain an organomagnesium compound solution (a3-2 ) Was synthesized.

To an eggplant flask C sufficiently dried and purged with argon, 25 mL of THF and 27 mg (0.05 mmol) of dehydrated and peroxide-removed treatment and 27 mg (0.05 mmol) of NiCl ₂ (dppp) were added and heated to 35 ° C. The organomagnesium compound solution (a3-1) was added, and the mixture was heated and stirred at 35 ° C. for 1.5 hours. Next, an organomagnesium compound solution (a3-2) was added and reacted at 35 ° C. for 2 hours. After completion of the reaction, 1.0M of t-butylmagnesium chloride
2 mL of THF solution was added and stirred at 35 ° C. for 1 hour, and then 30 mL of 5M hydrochloric acid was added and stirred at room temperature for 1 hour. This reaction solution was extracted with 450 mL of chloroform, and the organic layer was washed with 100 mL of sodium bicarbonate water and 100 mL of distilled water in this order. The organic layer was dried over anhydrous sodium sulfate and concentrated to dryness. By dissolving the obtained black-purple solid in 30 mL of chloroform, reprecipitating it in 300 mL of methanol, and thoroughly drying it using a preparative GPC column in the same manner as in Polymerization Example 3 A conjugated block copolymer C2 (721 mg) was obtained.

  According to the same GPC measurement as in Polymerization Example 1, the obtained conjugated block copolymer C2 has a weight average molecular weight (Mw) of 23,400, a number average molecular weight (Mn) of 20,800, and a dispersity (Mw / Mn) of 1.13.

(Comparative Example 3)
A diblock copolymer having a molar ratio of 3-hexylthiophene and 3-phenoxymethylthiophene of 1: 1 was synthesized to obtain a conjugated block copolymer C3 of Comparative Example 3. The detailed procedure of the synthesis of the conjugated block copolymer C3 followed Non-Patent Document 3. The resulting conjugated block copolymer C3 had a weight average molecular weight (Mw) of 22,500, a number average molecular weight (Mn) of 19,800, and a dispersity (Mw / Mn) of 1.14.

(Comparative Example 4)
A diblock copolymer having a molar ratio of 3-hexylthiophene and 3- [2- (2-methoxyethoxy) ethoxy] methylthiophene of 1: 1 was synthesized to obtain a conjugated block copolymer C4 of Comparative Example 4. . The detailed procedure of the synthesis of the conjugated block copolymer C4 followed Non-Patent Document 1. The resulting conjugated block copolymer C4 had a weight average molecular weight (Mw) of 25,100, a number average molecular weight (Mn) of 20,200, and a dispersity (Mw / Mn) of 1.24.

(Comparative Example 5)
A diblock copolymer having a molar ratio of 3-hexylthiophene to styrene of 1: 1 was synthesized to obtain a non-conjugated block copolymer C5 of Comparative Example 5. The detailed procedure for the synthesis of the non-conjugated block copolymer C5 followed Non-Patent Document 2. The obtained nonconjugated block copolymer C5 had a weight average molecular weight (Mw) of 24,000, a number average molecular weight (Mn) of 16,900, and a dispersity (Mw / Mn) of 1.42.

(Comparative Example 6)
A conjugated block copolymer C6 was synthesized according to the following reaction formula (18).

  Under a nitrogen atmosphere, a 100 mL three-necked flask was charged with a conjugated polymer block A4 (0.80 g) and a polymer represented by a conjugated polymer block A7 (0.80 g), toluene (20 mL), 2M aqueous potassium carbonate solution (10 mL, 20 mmol), tetrakis. (Triphenylphosphine) palladium (0) (20.5 mg, 17.7 μmol) and aliquat 336 (0.8 mg, 1.98 μmol) were added, followed by stirring at 80 ° C. for 24 hours. After completion of the reaction, the reaction solution was poured into methanol (200 mL), the precipitated solid was collected by filtration, washed with water (20 mL) and methanol (20 mL), and the resulting solid was dried under reduced pressure to obtain a crude product. It was. The crude product was washed with acetone (100 mL) and hexane (100 mL) using a Soxhlet extractor, and then extracted with chloroform (100 mL). The obtained solution was poured into methanol (1 L), and the precipitated solid was collected by filtration and dried under reduced pressure to obtain a conjugated block copolymer C6 as a black purple solid (0.67 g, 42%).

In the same manner as in Polymerization Example 1, physicochemical analysis of the resulting conjugated block copolymer C6 was performed.
¹ H-NMR (270 MHz): δ = 8.12-7.96 (m, 4H), 7.85-7.32 (m, 4H), 2.74 (t, J = 7.58 Hz, 4H) 2.35-1.31 (m, 38H), (m, 12H)
GPC (CHCl ₃ ): Mn = 36000 g / mol, Mw = 80900 g / mol, PDI = 2.25
This physicochemical analysis result supports the chemical structure shown in the reaction formula (14).

(Comparative Example 7)
The conjugated polymer block A1 was designated as conjugated polymer C7 of Comparative Example 7.

(Comparative Example 8)
The conjugated polymer block A3 was designated as conjugated polymer C8 of Comparative Example 8.

(Comparative Example 9)
The conjugated polymer C9 was synthesized according to the following reaction formula (19).

2,6-bis (trimethyltin) -4,8-dipropylbenzo [1,2-b: 4,5-b ′, which is a monomer constituting the conjugated polymer C9, in a 50 ml eggplant flask under a nitrogen atmosphere ] Dithiophene (0.45 g, 0.75 mmol) and 1- (4,6-dibromothieno [3,4-b] thiophen-2-yl) -2-ethylhexane-1-one (0.32 g, 0.75 mmol) ), DMF (6.2 mL), chlorobenzene (25 mL), tetrakis (triphenylphosphine) palladium (0) (9.2 mg, 7.8 μmol), and heated at 135 ° C. for 1 hour 30 minutes. Next, 2,5-dibromothiophene (1.84 g, 7.6 mmol) was added as a terminal blocking agent and heated at 115 ° C. for 16 hours. After completion of the reaction, the reaction solution was concentrated, poured into methanol (500 mL), the precipitated solid was collected by filtration, and the obtained solid was dried under reduced pressure to obtain a crude product. The crude product was washed with acetone (200 ml) and hexane (200 mL) using a Soxhlet extractor and then extracted with chlorobenzene (200 mL). The organic layer was concentrated to dryness, and the resulting black purple solid was dissolved in chlorobenzene (30 mL) and reprecipitated with methanol (300 mL).
The obtained conjugated polymer C9 (0.31 g, 77%) was subjected to physicochemical analysis in the same manner and under the same conditions as in Polymerization Example 8. The following physicochemical analysis results support the chemical structure shown in the above reaction formula.
1H NMR (270 MHz, CDCl3): δ = 7.60-7.30 (br, 3H), 3.30-3.00 (Br, 5H), 2.00-1.10 (br, 12H), 1 .00-0.70 (br, 12H)
GPC (CHCl ₃ ): Mn = 10,400 g / mol, Mw = 24,400 g / mol, PDI = 2.34

(Comparative Example 10)
A polymer blend D1 was prepared by mixing the conjugated polymer block A8 obtained in Polymerization Example 8 and the conjugated polymer C9 obtained in Comparative Example 9 at a weight fraction of 50:50.

(Production of mixed solution of conjugated block copolymer and electron accepting material)
16.0 mg of the conjugated block copolymer 1 obtained in Example 1, 12.8 mg of PCBM (E100H manufactured by Frontier Carbon Co.) as an electron-accepting material, and 1 mL of chlorobenzene as a solvent at 40 ° C. over 6 hours. Mixed. Then cooled to room temperature 20 ° C., to produce a solution containing conjugated block copolymer and _PC 61 BM was filtered through a PTFE filter having a pore size of 0.45 [mu] m.

A solution containing PC ₆₁ BM was produced by the same method for each of the polymers obtained in Examples 2, 5, 6 and Comparative Examples 1-5, 8.

For each of the polymers obtained in Examples 3 and 4 and Comparative Examples 6 and 7, 5.0 mg of the polymer and 20.0 mg of PC ₆₁ BM (E100H manufactured by Frontier Carbon Co.) were used as the electron-accepting material. Except for the above, a solution containing the polymer and PC ₆₁ BM was produced in the same manner as in the conjugated block copolymer 1.

For each of the polymers obtained in Examples 7 and 8 and Comparative Example 9, and for the polymer blend D1 obtained from Comparative Example 10, 10.0 mg of the polymer was used as an electron-accepting material, and PC ₇₁ BM (manufactured by Frontier Carbon Co., Ltd.) 1 mL of chlorobenzene mixed with 1,8-diiodooctane at a volume fraction of 2.5% was added as a solvent to the powder mixed with 15.0 mg of E110) as a solvent and mixed at 100 ° C. for 6 hours. Then cooled to room temperature 20 ° C., to produce a solution containing was filtered through a PTFE filter having a pore size of 1.00μm polymer and _PC 71 BM.

(Production and evaluation of organic solar cells)
A glass substrate provided with an ITO film (resistance value 10Ω / □) with a thickness of 150 nm by sputtering was subjected to surface treatment by ozone UV treatment for 15 minutes. A PEDOT: PSS aqueous solution (manufactured by HC Starck: CLEVIOS PH500) serving as a hole transport layer was formed on the substrate to a thickness of 40 nm by a spin coating method. After heating and drying at 140 ° C. for 20 minutes by a hot plate, a solution containing the polymer prepared above by spin coating and PC ₆₁ BM or a solution containing the polymer and PC ₇₁ BM was applied, and the organic thin film solar An organic photoelectric conversion layer (film thickness: about 100 nm) of the battery was obtained. After vacuum drying for 3 hours, Examples 1, 2, 5, 6 and Comparative Examples 1-5, 8 were subjected to thermal annealing at 120 ° C. for 30 minutes. Then, lithium fluoride was vapor-deposited with a film thickness of 1 nm by a vacuum vapor deposition machine, and aluminum was vapor-deposited with a film thickness of 100 nm. The degree of vacuum at the time of vapor deposition was 2 × 10 ⁻⁴ Pa or less. As a result, an organic thin film solar cell which is a photoelectric conversion element using a conjugated block copolymer was obtained. The shape of the organic thin film solar cell was a 5 × 5 mm regular square.

(Measurement of photoelectric conversion efficiency and solubility parameter)
The photoelectric conversion efficiencies of the organic thin-film solar cells obtained in each of the examples and comparative examples were measured with a 300 W solar simulator (trade name PEC L11: AM1.5G filter, irradiance 100 mW / cm ² , manufactured by Pexel Technology). . The measurement results are shown in Table 1, Table 2, and Table 3. Further, the solubility parameter of each polymer block constituting the conjugated block copolymer of each example was calculated by the Bicerano method using computer software Scigress Explorer Professional 7.6.0.52 (manufactured by Fujitsu). The solubility parameter of each polymer of Comparative Examples was also measured by the same method. The results are also shown in Tables 1 to 3.

Table 1 (Examples 1 to 4), Table 2 (Examples 5 to 8), Table 3 (Comparative Examples 1 to 5), and Table 4 (Comparative Examples 6 to 10) constitute conjugated block copolymers. The structure of the conjugated polymer block, the solubility parameter (SP value) of the conjugated polymer block, the difference in SP value, and the photoelectric conversion efficiency of the organic thin film solar cell are shown. Of the conjugated polymer blocks constituting the conjugated block copolymer, the conjugated polymer block having the maximum solubility parameter is the conjugated polymer block A, and the conjugated polymer block having the minimum solubility parameter is the conjugated polymer. Shown as block B. In addition, about the polymer blend D1 obtained in the comparative example 10, the difference of SP value of each blended homopolymer was shown in the table | surface.

  As can be seen from the evaluation, among the solubility parameters of the conjugated polymer block constituting each block, the difference between the maximum value (polymer block A) and the minimum value (polymer block B) is 0.6 or more and 2.0 or less. It can be seen that the organic thin-film solar cell using the conjugated block copolymer has higher conversion efficiency than the conventional conjugated block copolymer.

  Comparison between Example 1 and Comparative Examples 7 and 8, and further comparison between Examples 7 and 8 and Comparative Example 9, the conjugated block copolymer was converted from a conjugated polymer (conjugated homopolymer) consisting of a single monomer unit. It turns out that efficiency is high. In Examples 1 and 2, it is understood that the solubility parameter can be adjusted by changing the divalent heterocyclic group of the main chain, and a preferred conjugated block copolymer can be synthesized. By changing the length of the side chain (Example 3) or by appropriately selecting the number of fluorine atoms bonded to the side chain (Examples 4 and 6), each polymer block has a favorable solubility parameter difference. It can be seen that a conjugated block copolymer can be synthesized. It can also be seen that the solubility parameter can be appropriately adjusted by bonding a hydroxyl group to the side chain (Example 5). From Examples 5 and 7, it can be seen that the polymer block A or B may be a polymer block made of a random copolymer.

On the other hand, the difference between the maximum value (conjugated polymer block A) and the minimum value (conjugated polymer block B) among the solubility parameters of the conjugated polymer block constituting each block from Comparative Examples 1, 2, 3, and 6 is 0. It can be seen that high conversion efficiency cannot be obtained unless the range is from .6 to 2.0. Even if the difference in solubility parameter is within the prescribed range of the present invention, the block containing mainly Comparative Example 4 and an unconjugated polymer block having an alkyl group substituted with a functional group other than a fluorine atom and a hydroxyl group in the side chain. It turns out that the comparative example 5 which is a polymer has low conversion efficiency. Further, even in the case of a polymer blend obtained by blending polymers having a solubility parameter difference of 0.6 or more and 2.0 or less than Comparative Example 10, the conversion efficiency as in the conjugated block copolymer of the present invention may not be obtained. Recognize.

  The conjugated block copolymer which is a π-conjugated system of the present invention can be used as a photoelectric conversion layer of a photoelectric conversion element. Moreover, the photoelectric conversion element which consists of the conjugated block copolymer is used widely as various photosensors including a solar cell.

Claims (10)

A conjugated block copolymer containing at least two types of conjugated polymer blocks containing a divalent heterocyclic group in the main chain and containing a side chain which is an alkyl group or an alkoxy group which may be substituted with a fluorine atom or a hydroxyl group. A polymer comprising:
The difference in solubility parameter between the conjugated polymer block having the maximum solubility parameter and the conjugated polymer block having the minimum solubility parameter is 0.6 or more and 2.0 or less. Copolymer.   The conjugated polymer block has at least one heterocyclic skeleton selected from a condensed π-conjugated skeleton containing at least one thiophene ring as a part of the chemical structure, a carbazole skeleton, a dibenzosilole skeleton, and a dibenzogermol skeleton. The conjugated block copolymer according to claim 1, comprising a valent heterocyclic group in the main chain.   The conjugated polymer block is a cyclopentadithiophene diyl group, a dithienopyrrole diyl group, a dithienosilole diyl group, a dithienogermol diyl group, a benzodithiophene diyl group, a naphthodithiophene diyl group, a thienothiophene diyl group, The conjugated block copolymer according to claim 1, wherein the main chain contains at least one divalent heterocyclic group selected from a thienopyrrole dione diyl group and a diketopyrrolopyrrole diyl group.   Two types of the conjugated polymer block are the same or different types of the conjugated polymer block in which a side chain which is an alkyl group or alkoxy group having a minimum of 8 carbon atoms is bonded to the divalent heterocyclic group. The conjugate according to any one of claims 1 to 3, which is a conjugated polymer block in which a side chain which is an alkyl group or alkoxy group having a maximum of 6 carbon atoms is bonded to a valent heterocyclic group. Block copolymer.   The difference between the total number of carbon atoms in the side chain of one conjugated polymer block and the total number of carbon atoms in the side chain of the other conjugated polymer block is 6 or more and 16 or less. Conjugated block copolymer.   Two types of the conjugated polymer block are the same or different types of the divalent conjugated polymer block in which a side chain that is an alkyl group or an alkoxy group that does not contain fluorine is bonded to the divalent heterocyclic group. A conjugated polymer block in which a side chain which is an alkyl group or an alkoxy group substituted with a minimum of three fluorine atoms is bonded to the heterocyclic group of The conjugated block copolymer described in 1.   A composition comprising the conjugated block copolymer according to any one of claims 1 to 6 and a fullerene derivative.   An organic thin film comprising the conjugated block copolymer according to claim 1.   An organic thin film element comprising the organic thin film according to claim 8 on a substrate.   The organic thin film of Claim 8 is pinched | interposed between at least two electrodes, The photoelectric conversion element characterized by the above-mentioned.