JP2013237813A - π-ELECTRON CONJUGATED POLYMER, AND ORGANIC SEMICONDUCTOR DEVICE USING THE SAME - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a π-electron conjugated polymer which is excellent in heat stability and is small in band gap.SOLUTION: A π-electron conjugated polymer is represented by formula (1), wherein U is Si or Ge; Yis N and Yis CH or CF, or Yis CH or CF and Yis N; Z is one selected from the group consisting of S, Se and N-R; R, Rand Rare each independently a hydrogen atom, a fluorine atom, a 1-20C alkyl group which may have a substituent, a 6-20C aryl group which may have a substituent; and n is a positive number of ≥2.

Description

  The present invention relates to a π-electron conjugated polymer and an organic semiconductor device using the same.

  Solar cells are currently attracting attention as an effective energy source for increasing energy problems. As semiconductor materials for photovoltaic elements in solar cells, inorganic semiconductors such as compound semiconductors, amorphous silicon, polycrystalline silicon, and single crystal silicon are used. However, solar cell power generation is expensive compared to thermal power generation and nuclear power generation, which are currently mainstream, due to the high manufacturing cost of the inorganic semiconductor. A main factor that increases the manufacturing cost is that a thin film is formed by a vapor deposition process under high temperature and vacuum conditions. On the other hand, when an organic material such as a conjugated polymer is used as a semiconductor material, there is an advantage that a vapor deposition process is unnecessary and the manufacturing process can be simplified. For this reason, studies on organic solar cells using organic semiconductors and organic dyes have been underway.

Factors that determine the performance of the solar cell mainly include short-circuit current density (J _SC ), open-circuit voltage (V _OC ), and fill factor (FF). In particular, since the short-circuit current density greatly depends on the light absorption characteristics of the semiconductor material, a material having a wide light absorption region of the material can convert more light into electricity. In an organic material, a compound having a wide light absorption region requires a small energy difference (band gap) between the highest occupied orbital (HOMO) level and the lowest unoccupied orbital (LUMO) level. In addition, from the viewpoint of the processability of compounds at the time of device fabrication, research on polymers rather than small molecules has been actively promoted.

  A narrow band gap polymer (LBGP) is mentioned as a compound having these characteristics. For example, Non-Patent Document 1 discloses an example of an alternating copolymer of cyclopentadithiophene as a donor molecule and benzothiadiazole as an acceptor molecule as an example of LBGP. Examples of alternating copolymers with benzothiadiazole using dithienosilol as a donor molecule so as to have a wider light absorption region are disclosed in Patent Document 1 and Non-Patent Document 2. Non-Patent Document 3 discloses an alternating copolymer with cyclopentadithiophene using pyridinothiadiazole as an acceptor molecule.

  However, the conversion efficiency of the organic solar cell manufactured using LBGP disclosed in Patent Document 1 and Non-Patent Documents 1 to 3 is only about 5%. For further performance enhancement, HOMO and LUMO There is a need to develop materials with smaller band gaps. Further, the alternating copolymer of cyclopentadithiophene and pyridinothiadiazole disclosed in Non-Patent Document 3 has a problem that the thermal stability is poor and the durability of the organic solar cell is low, and improvement has been desired.

JP 2010-507233 A

J. et al. Peet et al. , Nature Materials, 2007, Vol. 6, 497-500. Jianhui Hou et al. , Journal of the American Chemical Society, 2008, 130, 16144-16145. Lei Ying et al. , Journal of the American Chemical Society, 2011, 133, 18538-18541.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a π-electron conjugated polymer having excellent thermal stability and a small band gap. Moreover, it aims at providing the organic-semiconductor device containing such a pi-electron conjugated polymer.

［式中、ＵはＳｉ又はＧｅであり、Ｙ^１がＮでＹ^２がＣＨ若しくはＣＦであるか、又はＹ^１がＣＨ若しくはＣＦでＹ^２がＮであり、ＺはＳ、Ｓｅ及びＮ-Ｒ^３からなる群から選択される１種であり、Ｒ^１、Ｒ^２及びＲ^３はそれぞれ独立して水素原子、フッ素原子、置換基を有してもよい炭素数１〜２０のアルキル基、置換基を有してもよい炭素数６〜２０のアリール基又は置換基を有してもよい炭素数４〜２０のヘテロアリール基であり、ｎは２以上の正数である。］
で示されるπ電子共役重合体を提供することによって解決される。このとき、上記π電子共役重合体の数平均分子量が１，０００〜１，０００，０００ｇ／モルであることが好適である。 The above problem is solved by the following general formula (1):

[Wherein U is Si or Ge and Y ¹ is N and Y ² is CH or CF, or Y ¹ is CH or CF and Y ² is N, Z is S, Se and N − R 1 is selected from the group consisting of R ³ , R ¹ , R ² and R ³ are each independently a hydrogen atom, a fluorine atom, a C 1-20 alkyl group which may have a substituent, It is a C6-C20 aryl group which may have a substituent, or a C4-C20 heteroaryl group which may have a substituent, and n is a positive number of 2 or more. ]
This is solved by providing a π-electron conjugated polymer represented by: At this time, it is preferable that the number average molecular weight of the π-electron conjugated polymer is 1,000 to 1,000,000 g / mol.

  Moreover, it is suitable that it is an organic-semiconductor composition containing the said (pi) electron conjugated polymer, and it is suitable that it is an organic semiconductor device containing the said (pi) electron conjugated polymer. Moreover, it is a suitable embodiment of this invention that an organic-semiconductor device is an organic transistor, and it is also a suitable embodiment of this invention that an organic-semiconductor device is a photoelectric conversion element.

  According to the present invention, a π-electron conjugated polymer having excellent thermal stability and a small band gap can be provided. In addition, it is possible to manufacture an organic semiconductor device having both high performance and stability.

It is a schematic cross section of a field effect transistor in which the π-electron conjugated polymer of the present invention is contained in an organic semiconductor layer. It is a schematic cross section of the photoelectric conversion element with which the pi-electron conjugated polymer of this invention contained in the photoactive layer.

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

The π-electron conjugated polymer of the present invention is represented by the general formula (1). In the π-electron conjugated polymer represented by the general formula (1), U is Si or Ge. Since U is Si or Ge, it has an advantage of excellent thermal stability. In the π-electron conjugated polymer represented by the general formula (1), Y ¹ is N and Y ² is CH or CF, or Y ¹ is CH or CF and Y ² is N. Among these, from the viewpoint of ease of synthesis and production cost, it is preferable that Y ¹ is N and Y ² is CH, or Y ¹ is CH and Y ² is N. Z is one selected from the group consisting of S, Se and N—R ³ . Among these, Z is preferably S or Se from the viewpoint of narrowing the band gap. R ¹ , R ² and R ³ are each independently a hydrogen atom, a fluorine atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, or an alkyl group having 6 to 20 carbon atoms which may have a substituent. It is a C4-C20 heteroaryl group which may have an aryl group or a substituent. From the viewpoint of ease of synthesis and production cost, R ¹ and R ² are preferably alkyl groups that may have a substituent. From the viewpoint of further expanding the π-conjugated system of the π-electron conjugated polymer of the present invention, the aryl group having 6 to 20 carbon atoms which may have a substituent or the number of carbons which may have a substituent. It is preferably a 4-20 heteroaryl group. The substituents that R ¹ , R ² and R ³ may have may be the same or different. In the polymer represented by the general formula (1), n is a positive number of 2 or more.

The alkyl group used for R ¹ , R ² and R ³ in the general formula (1) may be a linear or branched alkyl group or a cyclic cycloalkyl group. For example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, tert-pentyl group, linear or branched alkyl groups such as n-hexyl group, isohexyl group, 2-ethylhexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, dodecyl group; cyclopropyl group, Examples thereof include cycloalkyl groups such as a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, a cycloundecyl group, and a cyclododecyl group.

The alkyl group in R ¹ , R ² and R ³ may have a substituent. Examples of the substituent include aryl groups such as a phenyl group, a naphthyl group, an anthryl group, and a phenanthryl group; a pyridyl group, Heteroaryl groups such as thienyl group, furyl group, pyrrolyl group, imidazolyl group, pyrazinyl group, oxazolyl group, thiazolyl group, pyrazolyl group, benzothiazolyl group, benzoimidazolyl group; methoxy group, ethoxy group, n-propyloxy group, isopropoxy group , N-butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group, pentyloxy group, isopentyloxy group, neopentyloxy group, n-hexyloxy group, cyclohexyloxy group, heptyloxy group, n-octyl Oxy group, nonyloxy group, n-decyloxy Group, alkoxy group such as n-dodecyloxy group; alkylthio group such as methylthio group, ethylthio group, propylthio group, butylthio group; arylthio group such as phenylthio group, naphthylthio group; methoxycarbonyl group, ethoxycarbonyl group, propoxycarbonyl group, Alkoxy such as isopropoxycarbonyl group, n-butoxycarbonyl group, isobutoxycarbonyl group, sec-butoxycarbonyl group, tert-butoxycarbonyl group, pentyloxycarbonyl group, hexyloxycarbonyl group, heptyloxycarbonyl group, octyloxycarbonyl group Carbonyl group; alkyl sulfenyl group such as methyl sulfoxide group and ethyl sulfoxide group; aryl sulfoxide group such as phenyl sulfoxide group; Sulphonic acid ester groups such as onyloxy group, ethylsulfonyloxy group, phenylsulfonyloxy group, methoxysulfonyl group, ethoxysulfonyl group, phenyloxysulfonyl group; dimethylamino group, diphenylamino group, methylphenylamino group, methylamino group, ethyl Primary or secondary amino group such as amino group; methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl substituted with acetyl group, benzoyl group, benzenesulfonyl group, tert-butoxycarbonyl group, etc. Group, an amino group optionally substituted with an alkyl group such as a tert-butyl group or a phenyl group or an aryl group; a cyano group; a nitro group; a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom or an iodine atom; Can be mentioned

Examples of the aryl group used in R ¹ , R ² and R ³ in the general formula (1) include a phenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. These aryl groups may have a substituent, and as such a substituent, a substituent other than the aryl group exemplified in the description of the alkyl group, the above-described alkyl group, and the like can be used.

Examples of the heteroaryl group used in R ¹ , R ² and R ³ in the general formula (1) include a pyridyl group, a thienyl group, a furyl group, and a pyrrolyl group. These heteroaryl groups may have a substituent, and as such a substituent, a substituent other than the heteroaryl group exemplified in the description of the alkyl group, the above-described alkyl group, and the like can be used.

As the monomer unit contained in the π-electron conjugated polymer of the present invention represented by the general formula (1), only the same monomer including the structures of R ¹ , R ² and R ³ may be used. And unless the effect of this invention is impaired, another monomer may be contained.

  The π-electron conjugated polymer of the present invention represented by the general formula (1) includes a donor molecule monomer represented by the following general formula (2) and an acceptor represented by the following general formula (3) in the presence of a catalyst. It can be produced by polymerizing a molecular monomer by a so-called coupling reaction.

In the general formulas (2) and (3), U, R ¹ , R ² , Y ¹ , Y ² and Z have the same meanings as the general formula (1). M ^p1 and M ^p2 are not the same and are each independently a halogen atom, boronic acid, boronic ester, -MgX, -ZnX, -SiX ₃ and -SnRa ₃ (where Ra is a linear alkyl group having 1 to 4 carbon atoms) , X is one selected from the group consisting of halogen atoms. That is, when M ^p1 is a halogen atom, M ^p2 is one selected from the group consisting of boronic acid, boronic acid ester, —MgX, —ZnX, —SiX ₃ and —SnRa ₃ (wherein X and Ra are the same as above). It is. Conversely, when M ^p2 is a halogen atom, M ^p1 is selected from the group consisting of boronic acid, boronic ester, —MgX, —ZnX, —SiX ₃ and —SnRa ₃ (wherein X and Ra are the same as above) It is a seed. Examples of the halogen atom used for X include fluorine, chlorine, bromine and iodine.

In addition, the π-electron conjugated polymer of the present invention represented by the general formula (1) is a compound represented by the above general formulas (2), (3) and the formula Ar- ^Mq (hereinafter abbreviated as a terminal blocking agent). It is also possible to produce by carrying out a coupling reaction using However, Ar is an aryl group. M ^q is M ^r or a halogen atom. M ^r is one boronic acid, boronic acid ester, -MgX, -ZnX, -SiX ₃ and -SnRa ₃ (wherein X and Ra are said similar) is selected from the group consisting of.

  It is preferable to use a transition metal complex as the catalyst. 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 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, such as a nitrogen-containing ligands such as acetonitrile can be preferably used.

  In addition, although the usage-amount of a complex changes with pi electron conjugated polymers of this invention shown by the said General formula (1) to manufacture, 0.001-0.1 mol is preferable with respect to a monomer. When there are too many catalysts, it will cause the molecular weight fall of the polymer obtained. It is also economically disadvantageous. On the other hand, when there are too few catalysts, reaction rate will become slow and stable production will become difficult.

  The π-electron conjugated polymer of the present invention represented by the general formula (1) is preferably produced in the presence of a solvent. The solvent that can be used for the production needs to be properly selected depending on the kind of the π-electron conjugated polymer of the present invention represented by the above general formula (1) to be produced. it can. Examples of the solvent used here include 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. Ether solvents such as methyl ether and diphenyl ether; aliphatic or alicyclic saturated hydrocarbon solvents such as pentane, hexane, heptane and cyclohexane; aromatic hydrocarbon solvents such as benzene, toluene and xylene; Alkyl halide solvents; aromatic aryl halide solvents such as chlorobenzene and dichlorobenzene; solvents such as dimethylformamide, diethylformamide and N-methylpyrrolidone De solvents; such as water and mixtures thereof. The amount of the solvent used is preferably in the range of 1 to 1000 times the mass of the monomer of the π-electron conjugated polymer represented by the general formula (1) to be produced. Among these, from the viewpoint of the solubility of the obtained π-electron conjugated polymer represented by the above general formula (1) and the stirring efficiency of the reaction solution, it is more preferably 10 mass times or more, and from the viewpoint of the reaction rate, 100 mass. It is more preferable that the ratio is not more than twice.

  In the present invention, the polymerization temperature varies depending on the kind of the π-electron conjugated polymer of the present invention represented by the general formula (1) to be produced, but is usually in the range of −80 ° C. to 200 ° C. In the present invention, the pressure of the reaction system is not particularly limited, but is preferably from 0.1 to 10 atm, and more preferably at about 1 atm. The reaction time is preferably 20 minutes to 150 hours.

  The π-electron conjugated polymer represented by the general formula (1) can be used for normal operations such as reprecipitation, solvent removal under heating, solvent removal under reduced pressure, and solvent removal with steam (steam stripping). Can be isolated and obtained from the reaction solution. The crude product thus obtained can be purified by washing or extraction using a commercially available solvent using a Soxhlet extractor. Examples of the solvent used here include ether solvents such as tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, dimethyl ether, and ethyl methyl ether; aliphatic or alicyclic saturation such as pentane, hexane, heptane, and cyclohexane. Hydrocarbon solvents; aromatic hydrocarbon solvents such as benzene, toluene and xylene; ketone solvents such as acetone, ethyl methyl ketone and diethyl ketone; alkyl halide solvents such as dichloromethane and chloroform; chlorobenzene and dichlorobenzene Aromatic aryl halide solvents; amide solvents such as dimethylformamide, diethylformamide, N-methylpyrrolidone; water and mixtures thereof.

The π-electron conjugated polymer of the present invention represented by the general formula (1) has M ^p1 and M ^p2 as end groups (where M ^p1 and M ^p2 are as defined in the general formulas (2) and (3)), Alternatively, they may have a detached hydrogen atom. Further, a terminal structure in which these terminal groups are substituted with an end-capping agent such as an aryl group may be used.

  The number average molecular weight of the π-electron conjugated polymer of the present invention represented by the general formula (1) is 1,000 to 1,000,000 g / mol from the viewpoint of processability, crystallinity, solubility, photoelectric conversion characteristics, and the like. Preferably, it is 5,000-200,000 g / mol. If the number average molecular weight is too high, the solubility is lowered, and the workability of a thin film or the like may be lowered. On the other hand, if the number average molecular weight is too low, the crystallinity, film stability, photoelectric conversion characteristics and the like may be deteriorated. Here, the number average molecular weight means a molecular weight in terms of polystyrene by gel permeation chromatography (hereinafter sometimes referred to as GPC). The number average molecular weight of the π-electron conjugated polymer of the present invention represented by the general formula (1) can be obtained by ordinary GPC using a solvent such as tetrahydrofuran (THF), chloroform, dimethylformamide (DMF) or the like. it can. However, some of the π-electron conjugated polymers of the present invention represented by the general formula (1) have low solubility around room temperature. In such a case, the high temperature GPC chromatography using dichlorobenzene, trichlorobenzene or the like as a solvent. You may obtain | require a number average molecular weight.

  The decomposition temperature of the π-electron conjugated polymer of the present invention represented by the general formula (1) is preferably 400 ° C. or higher from the viewpoint of producing an organic semiconductor device having good durability. Here, the decomposition temperature is a temperature at which the weight of the polymer is reduced by 10%.

  The band gap (Eg) of the π-electron conjugated polymer of the present invention represented by the general formula (1) is 1.45 eV or less from the viewpoint of converting light on a longer wavelength side into electric energy and obtaining a high current. Preferably, it is 1.40 eV or less, and more preferably 1.35 eV or less. Moreover, the band gap (Eg) of the π-electron conjugated polymer of the present invention represented by the general formula (1) is usually 1.10 eV or more.

  The π electron conjugated polymer of the present invention represented by the general formula (1) can be suitably used as an organic semiconductor material. Among these, it can be used for organic semiconductor devices such as organic transistors such as field effect transistors and photoelectric conversion elements such as organic thin film solar cells.

  The organic semiconductor composition containing the π-electron conjugated polymer in the present invention is not particularly limited as long as it contains the π-electron conjugated polymer of the present invention, organic semiconductor materials other than the present invention, solvents, crystallization agents, It includes compositions with antioxidants, various forms of metal materials, inorganic crystals and so on. When the π-electron conjugated polymer of the present invention is formed into a film by a coating process, it may be in the form of a solution containing at least one component that can dissolve the π-electron conjugated polymer of the present invention. Further, when the π-electron conjugated polymer of the present invention is used as a device, it may be a solution to which a poor solvent is added in order to improve the crystallinity of the polymer, and the stability of the π-electron conjugated polymer of the present invention. Stabilizers such as antioxidants may be included for the purpose of improving the resistance. A thin film after the above solution is formed by various coating methods and the solvent is distilled off is also included in the composition of the present invention. In addition, when the π-electron conjugated polymer of the present invention is used as an organic photoelectric conversion element, an electron-accepting semiconductor may be included.

  Next, an organic field effect transistor will be described with reference to the drawings as an example of an organic semiconductor device including the π-electron conjugated polymer of the present invention represented by the general formula (1).

  In an organic field effect transistor, a gate electrode layer to which a voltage is applied, an insulator layer, a source-drain electrode layer serving as a current path, and an organic semiconductor layer are stacked on a substrate. There are a bottom gate / top contact type, a bottom gate / bottom contact type, a top gate / bottom contact type, and a top gate / top contact type, depending on the stacking arrangement of each layer. As the organic semiconductor material forming the organic semiconductor layer 1, the π-electron conjugated polymer of the present invention represented by the general formula (1) of the present invention is used.

  A preferred embodiment of the organic field effect transistor is shown in FIG.

  As shown in FIG. 1A, the organic field effect transistor 10 includes a gate electrode layer composed of a gate electrode 5, an insulator layer 4, a source electrode 2, and a drain electrode 3 on an insulating support substrate 6 that is a substrate. The bottom-gate / bottom-contact type is an organic semiconductor layer 1 containing a source-drain electrode layer and a polymer represented by the general formula (1) of the present invention. The gate electrode 5 controls the current flowing in the current path, and is isolated from the organic semiconductor layer 1 and the source-drain electrode layer by the insulator layer 4. The source-drain electrode layer is deposited on the organic semiconductor layer 1 and forms a channel region that becomes a current path between the source electrode 2 and the drain electrode 3.

  The arrangement of these layers and electrodes can be appropriately selected depending on the use of the electronic device. As shown in FIG. 1B, the organic field effect transistor 10 includes a gate electrode 5, an insulator layer 4, an organic semiconductor layer 1, and a source electrode 2 and a drain electrode on an insulating substrate 6 that is a substrate. 3 may be a bottom-gate / top-contact type in which source-drain electrode layers composed of 3 are sequentially stacked. The structure of the organic field effect transistor 10 is not particularly limited. For example, when the organic semiconductor layer 1 is exposed, a protective film for minimizing the influence of outside air on the organic semiconductor layer 1 is the organic semiconductor layer 1. It may be formed on the top.

  The organic field effect transistor 10 generates an electric field when a voltage is applied to the gate electrode 5, and forms a channel region L serving as a current path between the source electrode 2 and the drain electrode 3 in the source-drain electrode layer. In the source-drain electrode layer and the organic semiconductor layer 1, electrons are supplied from the source electrode 2 to the organic semiconductor layer 1, electrons are discharged from the organic semiconductor layer 1 to the drain electrode 3, and a current flows. . The transistor operation is performed by changing the carrier density of the organic semiconductor layer 1 and the insulator layer 4 and changing the amount of current flowing between the source electrode 2 and the drain electrode 3.

  The material of the organic semiconductor layer 1 is the π electron conjugated polymer of the present invention represented by the general formula (1). The thickness of the organic semiconductor layer 1 is preferably about 1 nm to 10 μm, and more preferably about 10 to 500 nm. The organic semiconductor layer 1 is formed by dissolving the π-electron conjugated polymer of the present invention represented by the general formula (1) in a solvent and applying it by a cast, dip, spin coating method, or by vacuum deposition can do. The organic semiconductor layer 1 may contain other components such as a surfactant, a binder resin, and a filler as long as the object of the present invention is not impaired.

  Moreover, a photoelectric conversion element is illustrated suitably as an example of the organic-semiconductor device containing the (pi) electron conjugated polymer of this invention shown by General formula (1) of this invention. Hereinafter, description will be given with reference to the drawings.

  A preferable embodiment of the photoelectric conversion element is shown in FIG.

  As shown in FIG. 2, the photoelectric conversion element 20 includes a positive electrode 25 that is a transparent electrode, a hole transport layer 24 that is an arbitrary smooth layer, a π of the present invention represented by the general formula (1), on a substrate 26. A photoelectric conversion active layer 23 containing an electron conjugated polymer, an electron transport layer 22 which is an arbitrary smooth layer, and a negative electrode (electrode) 21 are sequentially laminated. The structure of the photoelectric conversion element 20 is not limited to these, and the positive electrode and the negative electrode, the hole transport material, and the electron transport material may be interchanged depending on the characteristics of the material.

  The π-electron conjugated polymer of the present invention represented by the general formula (1) can be used for the photoelectric conversion active layer 23 of the photoelectric conversion element 20 by forming an organic semiconductor composition with an electron accepting material. The electron-accepting material constituting the composition is not particularly limited as long as it is an organic material exhibiting n-type semiconductor characteristics. For example, 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA), 3,4 , 9,10-perylenetetracarboxylic dianhydride (PTCDA), N, N′-dioctyl-3,4,9,10-naphthyltetracarboxydiimide (NTCDI-C8H), 2- (4-biphenylyl) -5 Oxazole derivatives such as (4-t-butylphenyl) -1,3,4-oxadiazole and 2,5-di (1-naphthyl) -1,3,4-oxadiazole; 3- (4-biphenylyl) ) -4-azole-5- (4-tert-butylphenyl) -1,2,4-triazole and other triazole derivatives; phenanthroline derivatives , C60, C70 and the like fullerene derivatives; carbon nanotubes (CNT), poly-p-phenylene vinylene-based polymers introduced with a cyano group (CN-PPV), and the like. These may be used alone or in combination of two or more. Among these, fullerene derivatives are preferably used from the viewpoint of an n-type semiconductor that is stable and excellent in carrier mobility.

  The fullerene derivatives include unsubstituted ones such as C60, C70, C76, C78, C82, C84, C90, and C94, and [6,6] -phenyl C61 butyric acid methyl ester ([6,6]- C61-PCBM), [5,6] -phenyl C61 butyric acid methyl ester, [6,6] -phenyl C61 butyric acid n-butyl ester, [6,6] -phenyl C61 butyric acid i-butyl ester [6,6] -phenyl C61 butyric acid hexyl ester, [6,6] -phenyl C61 butyric acid dodecyl ester, [6,6] -diphenyl C62 bis (butyric acid methyl ester) ([6,6 ] -C62-bis-PCBM), [6,6] -phenyl C71 And substituted derivatives, including Ji butyric acid methyl ester ([6,6] -C71-PCBM) and the like.

  In the present invention, the above fullerene derivatives can be used alone or as a mixture thereof. From the viewpoint of solubility in organic solvents, [6,6] -C61-PCBM, [6,6] -C62-bis-PCBM ), [6,6] -C71-PCBM is preferably used.

  The ratio of the electron-accepting material in the composition is preferably 10 to 1000 parts by mass, and 50 to 500 parts per 100 parts by mass of the π-electron conjugated polymer of the present invention represented by the general formula (1). More preferably, it is part by mass.

  The composition may contain other components such as a surfactant, a binder resin, a metal, and a filler as long as the object of the present invention is not impaired.

  The mixing method of the π-electron conjugated polymer of the present invention represented by the general formula (1) and the electron-accepting material is not particularly limited, but after adding the solvent in a desired ratio, heating, stirring, Examples thereof include a method in which one or more methods such as sonication are combined and dissolved in a solvent to form a solution.

  Although it does not specifically limit as a solvent, For each of the pi-electron conjugated polymer and the electron-accepting material of the present invention represented by the general formula (1), it is preferable to use a solvent having a solubility at 20 ° C. of 1 mg / mL or more. It is preferable from the viewpoint on the film. When the solubility is 1 mg / mL or less, it is difficult to produce a homogeneous organic thin film, and the composition of the present invention cannot be obtained. Furthermore, from the viewpoint of arbitrarily controlling the film thickness of the organic thin film, the solubility at 20 ° C. is 3 mg / mL or more for each of the π electron conjugated polymer of the present invention represented by the general formula (1) and the electron accepting material. It is more preferable to use the solvent. Further, the boiling point of these solvents is preferably in the range of room temperature to 200 ° C. from the viewpoint of film forming properties and the manufacturing process described later.

  Examples of the solvent include tetrahydrofuran, 1,2-dichloroethane, cyclohexane, chloroform, bromoform, benzene, toluene, o-xylene, chlorobenzene, bromobenzene, iodobenzene, o-dichlorobenzene, anisole, methoxybenzene, trichlorobenzene, pyridine, and the like. Is mentioned. These solvents may be used alone or as a mixture of two or more. However, the solubility of the π electron conjugated polymer of the present invention represented by the general formula (1) and the electron accepting material is particularly high. -Dichlorobenzene, chlorobenzene, bromobenzene, iodobenzene, chloroform and mixtures thereof are preferred. More preferably, o-dichlorobenzene, chlorobenzene and a mixture thereof are used.

  The solution may contain an additive having a boiling point higher than that of the solvent in addition to the π-electron conjugated polymer of the present invention represented by the general formula (1) and the electron-accepting material. In the process of forming an organic thin film by containing an additive, a fine and continuous phase separation structure of the π-electron conjugated polymer and the electron-accepting material of the present invention represented by the general formula (1) is formed. It becomes possible to obtain the photoelectric conversion active layer 23 excellent in photoelectric conversion efficiency. Examples of the additive include octanedithiol (boiling point: 270 ° C.), dibromooctane (boiling point: 272 ° C.), diiodooctane (boiling point: 327 ° C.) and the like.

  The addition amount of the additive is not particularly limited as long as the π-electron conjugated polymer and the electron-accepting material of the present invention represented by the general formula (1) do not precipitate and give a uniform solution. On the other hand, the volume fraction is preferably 0.1% to 20%. When the additive amount is less than 0.1%, a sufficient effect cannot be obtained to form a fine and continuous phase separation structure. When the additive amount is more than 20%, The drying speed becomes slow and it becomes difficult to obtain a homogeneous organic thin film. More preferably, it is in the range of 0.5% to 10%.

  The film thickness of the organic photoelectric conversion layer 23 is usually 1 nm to 1 μm, preferably 2 nm to 1000 nm, more preferably 5 nm to 500 nm, and further preferably 20 nm to 300 nm. If the film thickness is too thin, the light is not sufficiently absorbed, and conversely if it is too thick, the carriers are difficult to reach the electrode.

  The method for coating the substrate or the support containing the π-electron conjugated polymer of the present invention represented by the general formula (1) and the electron-accepting material is not particularly limited, and a liquid coating material is used. Any conventionally known coating method can be employed. For example, dip coating method, spray coating method, ink jet method, aerosol jet method, spin coating method, bead coating method, wire bar coating method, blade coating method, roller coating method, curtain coating method, slit die coater method, gravure coater method , Slit reverse coater method, micro gravure method, comma coater method, etc. can be adopted, and the coating method can be selected according to the coating film properties to be obtained, such as coating thickness control and orientation control. That's fine.

  The organic photoelectric conversion layer 23 may be further subjected to thermal annealing as necessary. Thermal annealing is performed by holding the substrate on which the organic thin film is formed at a desired temperature. Thermal annealing may be performed under reduced pressure or in an inert gas atmosphere, and a preferable temperature is 40 ° C to 300 ° C, more preferably 70 ° C to 200 ° C. If the temperature is low, a sufficient effect cannot be obtained. If the temperature is too high, the organic thin film is oxidized and / or decomposed, and sufficient photoelectric conversion characteristics cannot be obtained.

  The substrate 26 on which the photoelectric conversion element 20 is formed may be any substrate that does not change when the electrode or the organic photoelectric conversion layer 23 is formed. For example, inorganic materials such as alkali-free glass and quartz glass, metal films such as aluminum, and any organic material such as polyester, polycarbonate, polyolefin, polyamide, polyimide, polyphenylene sulfide, polyparaxylene, epoxy resin and fluorine resin Films and plates produced by the method can be used. When a transparent substrate is used, the substrate-side electrode is preferably transparent or translucent. Although the film thickness of the board | substrate 26 is not specifically limited, Usually, it is the range of 1 micrometer-10 mm.

  In the said photoelectric conversion element 20, it is preferable that any one electrode of the positive electrode 25 and the negative electrode 21 has a light transmittance. The light transmittance of the electrode is not particularly limited as long as incident light reaches the organic photoelectric conversion layer 23 and an electromotive force is generated. The thickness of the electrode may be in a range having light transparency and conductivity, and is preferably 20 nm to 300 nm, although it varies depending on the electrode material.

  Examples of the electrode material having optical transparency include a conductive metal oxide film and a translucent metal thin film. Specifically, indium oxide, zinc oxide, tin oxide, and their composites, indium tin oxide (ITO), fluorine tin oxide (FTO), antimony tin oxide, indium zinc oxide A film made using a conductive material made of (IZO), gallium / zinc / oxide, aluminum / zinc / oxide, antimony / zinc / oxide, or an ultrathin film of gold, platinum, silver, or copper is used. Of these, ITO, FTO, IZO, and tin oxide are preferable. Examples of the method for producing the electrode include a vacuum deposition method, a sputtering method, an ion plating method, and a plating method. Moreover, you may use organic transparent conductive films, such as polyaniline and its derivative (s), polythiophene, and its derivative (s) as a transparent electrode material.

  As the counter electrode material, a known metal, a conductive polymer, or the like can be used, and it may not have optical transparency, and may be transparent or translucent. Preferably, one of the pair of electrodes is preferably made of a material having a low work function. For example, metals such as lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, aluminum, scandium, vanadium, zinc, yttrium, indium, cerium, samarium, europium, terbium, ytterbium, and two of them One or more alloys, or one or more of them, and an alloy of one or more of gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten, tin, graphite, or a graphite intercalation compound are used. It is done. Examples of the alloy include magnesium-silver alloy, magnesium-indium alloy, magnesium-aluminum alloy, indium-silver alloy, lithium-aluminum alloy, lithium-magnesium alloy, lithium-indium alloy, calcium-aluminum alloy, and the like.

  The electrode used for the photoelectric conversion element of the present invention preferably uses a conductive material having a high work function on one side and a conductive material having a low work function on the other side. At this time, an electrode using a conductive material having a high work function is a positive electrode, and an electrode using a conductive material having a low work function is a negative electrode. In the photoelectric conversion element 20 shown in FIG. 2, the substrate side is a positive electrode 25 that is a transparent electrode, and the side far from the substrate is a negative electrode 21 that is a counter electrode.

  In the photoelectric conversion element 20, a hole transport layer 24 may be provided between the positive electrode 25 and the organic photoelectric conversion layer 23 as necessary. The material for forming the hole transport layer 24 is not particularly limited as long as it has p-type semiconductor characteristics. However, the polythiophene polymer, the polyaniline polymer, the poly-p-phenylene vinylene polymer, and the polyfluorene polymer are not particularly limited. Conductive polymers such as polymers, low molecular organic compounds exhibiting p-type semiconductor properties such as phthalocyanine derivatives (H2Pc, CuPc, ZnPc, etc.), porphyrin derivatives, metal oxides such as molybdenum oxide, zinc oxide, and vanadium oxide. Preferably used. The thickness of the hole transport layer 24 is preferably 1 nm to 600 nm, and more preferably 20 nm to 300 nm.

  When the hole transport layer 24 is formed between the positive electrode 25 and the organic photoelectric conversion layer 23, for example, in the case of a conductive polymer soluble in a solvent, a dip coating method, a spray coating method, an ink jet method, an aerosol jet method. , Spin coating method, bead coating method, wire bar coating method, blade coating method, roller coating method, curtain coating method, slit die coater method, gravure coater method, slit reverse coater method, micro gravure method, comma coater method, etc. can do. When using a low molecular weight organic material such as a phthalocyanine derivative or a porphyrin derivative, it is preferable to apply a vapor deposition method using a vacuum vapor deposition machine. Further, the electron transport layer 22 described below can be similarly produced.

  In the photoelectric conversion element 20, an electron transport layer 22 may be provided between the negative electrode 21 and the organic photoelectric conversion layer 23 as necessary. The material for forming the electron transport layer 22 is not particularly limited as long as it has n-type semiconductor characteristics, but the above-described electron-accepting materials (NTCDA, PTCDA, NTCDI-C8H, oxazole derivatives, triazole derivatives, phenanthroline derivatives, Fullerene derivatives, CNT, CN-PPV, etc.) are preferably used. The thickness of the electron transport layer 22 is preferably 1 nm to 600 nm, and more preferably 5 nm to 100 nm.

  In the photoelectric conversion element 20, a metal fluoride may be provided as a buffer layer that further facilitates charge transfer between the negative electrode 21 and the organic photoelectric conversion layer 23. Examples of the metal fluoride include lithium fluoride, sodium fluoride, potassium fluoride, magnesium fluoride, calcium fluoride, cesium fluoride, and particularly preferably lithium fluoride and cesium fluoride. The buffer layer preferably has a thickness of 0.05 nm to 50 nm, more preferably 0.5 nm to 20 nm. The buffer layer may be used in combination with the electron transport layer 22 described above, and when used in combination, the buffer layer is preferably formed on the electrode side.

  The photoelectric conversion element 20 can be applied to various photoelectric conversion devices using a photoelectric conversion function, an optical rectification function, and the like. For example, it is useful for photovoltaic cells (such as solar cells), electronic elements (such as optical sensors, optical switches, and phototransistors), optical recording materials (such as optical memories), and the like.

  Examples of the present invention will be described in detail below, but the present invention is not limited to these examples. In addition, the physical-property measurement and refinement | purification of the (pi) electron conjugated polymer of this invention manufactured at each said process and the following process were performed as follows.

(Weight average molecular weight (Mw) / Number average molecular weight (Mn))
The number average molecular weight and the weight average molecular weight are both determined in terms of polystyrene based on measurement by gel permeation chromatography (GPC). Here, HLC-8020 (product number) manufactured by Tosoh Corporation was used as the GPC apparatus, and two TSKgel Multipore HZs manufactured by Tosoh Corporation were connected in series as the column.

(Measurement of thermal decomposition temperature)
The pyrolysis temperature was measured using a differential thermal-thermogravimetric simultaneous measurement device (TG-DTA; Thermo Plus 8120) manufactured by Rigaku Corporation. Specifically, the temperature at which the weight of each polymer was reduced by 10% during the temperature rising process from room temperature to 600 ° C. at a temperature rising rate of 10 ° C./min was evaluated as the thermal decomposition temperature.

(Measurement of band gap (Eg))
The measurement of the band gap was performed using an ultraviolet-visible-near infrared spectrophotometer (Solid Spec 3700) manufactured by Shimadzu Corporation. Specifically, the wavelength of the absorption edge of the absorption spectrum is expressed by the following photon energy equation: E = hν = h (c / λ)
Was obtained as an optical band gap.
h: Planck constant (J · s), E: energy (eV), ν: frequency (Hz), c: speed of light (m / s), λ: wavelength (nm)

Synthesis Example 1 [Synthesis of 4,7-dibromo [1,2,5] selenadiazolo [3,4-c] pyridine represented by Formula (3a)]

  The three-necked flask was filled with argon gas, 1.33 g (4.99 mmol) of 3,4-diamino 1,5-dibromopyridine represented by the formula (4) and 27 ml of ethanol were added and refluxed. In a refluxed state, 0.573 g (5.16 mmol) of selenium dioxide dissolved in 11 ml of warm water was added dropwise. After refluxing for 3 hours, the mixture was filtered off, and the resulting yellow solid was recrystallized from ethyl acetate. ] Pyridine (sometimes abbreviated as PSeA) was obtained (1.13 g, 3.31 mmol, 66.5% yield).

The NMR data and mass spectrometry result of PSeA represented by the formula (3a) were as follows.
¹ H-NMR (CDCl ₃ , 400 MHz): δ = 8.396 (s, 1H)
¹³ C-NMR (CDCl ₃ , 400 MHz): δ = 158.38, 154.37, 144.21, 139.64, 114.26
MS: m / z = 343

(Example 1) [Synthesis of polymer represented by formula (1a)]

1,1-bis (2-ethylhexyl) -3,6-bis (trimethylstannyl) dithieno [3,2-b: 2 ′, represented by the formula (2a) as a donor molecule monomer in a two-necked flask 3′-d] germole (which may be abbreviated as DTGSn2, DTGSn2 is synthesized by the method described in Organometallics, 2007, Vol. 6, 497-500), 0.296 g (0.375 mmol) Filled with argon gas. Thereafter, 4,7-dibromo [1,2,5] thiadiazolo [3,4-c] pyridine represented by the formula (3b) as a monomer of the acceptor molecule (sometimes abbreviated as PTA, PTA is Journal) of Materials Chemistry, 2011, Vol. 21, pp. 13247-13255) 0.1187 g (0.402 mmol), tris (dibenzylideneacetone) dipalladium (Pd ₂ (dba) ₃ 7.4 mg (8.08 μmol), tri (o-tolyl) phosphine (sometimes abbreviated as P (o-Tol) ₃ ) 12.4 mg (40.7 μmol) and 10 ml of chlorobenzene. added. After degassing, the reaction solution was refluxed. The mixture was allowed to react for 5 days, returned to room temperature, and the precipitated solid was filtered off.

  30 mL of an aqueous solution in which 3.1 g of sodium N, N-diethylcarbamate trihydrate was dissolved was added to the filtrate, and the mixture was stirred and heated at 80 ° C. for 2 hours. The temperature was returned to room temperature, and the organic layer was washed twice with water, twice with a 3% aqueous acetic acid solution, and further twice with water. The organic layer was taken and dried over anhydrous magnesium sulfate, and then the solvent was distilled off with an evaporator. It was dissolved in a minimum amount of chloroform, reprecipitated with methanol, and the precipitate was filtered with a cylindrical filter paper. Thereafter, the precipitate was subjected to Soxhlet washing in the order of methanol, hexane, acetone, and ethyl acetate. The precipitate remaining on the cylindrical filter paper was recovered by Soxhlet with chloroform. The solvent was distilled off with an evaporator, dissolved in chloroform, and reprecipitated with ethyl acetate. The precipitate was collected by filtration and dried under reduced pressure to obtain a black polymer represented by the formula (1a) (95.3 mg, 0.159 mmol, yield 40%).

The NMR data, number average molecular weight, weight average molecular weight and polydispersity of the polymer represented by the formula (1a) were as follows.
¹ H-NMR (CDCl ₃ , 400 MHz): δ = 8.8-8.6 (m, 2H), 8.2 (s, 1H), 2-1.1 (m, 22H), 1.1- 0.7 (m, 12H)
GPC: Mn = 4600, Mw = 7200, polydispersity (Mw / Mn) = 1.57

(Example 2) [Synthesis of polymer represented by formula (1b)]

1,1-bis (2-ethylhexyl) -3,6-bis (trimethylstannyl) dithieno [3,2-b: 2 ′, represented by the formula (2b) as a donor molecule monomer in a two-necked flask 3′-d] silole (sometimes abbreviated as DTSSn2, DTSSn2 is synthesized by the method described in Journal of the American Chemical Society, 2008, Vol. 130, pages 16144-16145). 98.8 mg (0.133 mmol) was added and filled with argon gas. Thereafter, 39.3 mg of the PTA of the formula _{(3b) (0.133mmol), Pd} 2 (dba) 3 and 2.5mg (2.73μmol), P (o -Tol) 3 and 4.1 mg (13. 5 μmol) and 10 ml of chlorobenzene were added to obtain a polymer represented by the formula (1b) in the same manner as in Example 1 (32.2 mg, 0.0581 mmol, yield 44%).

The NMR data, number average molecular weight, weight average molecular weight and polydispersity of the polymer represented by the formula (1b) were as follows.
¹ H-NMR (CDCl ₃ , 400 MHz): δ = 8.8-8.7 (m, 2H), 8.2 (s, 1H), 1.5 (Br, 2H), 1.2 (m, 20H), 0.9 (m, 12H)
GPC: Mn = 7400, Mw = 1500, polydispersity (Mw / Mn) = 1.69

(Example 3) [Synthesis of polymer represented by formula (1c)]

As a donor molecule monomer, 0.359 g (0.455 mmol) of DTGSn2 represented by the formula (2a) was placed in a two-necked flask and filled with argon gas. Then, equation PSeA represented by _{(3a) 0.155g (0.453mmol),} Pd 2 (dba) 3 and 8.4mg (9.17μmol), P (o -Tol) 3 and 14.0 mg (46. 0 μmol) and 15 ml of chlorobenzene were added to obtain a polymer represented by the formula (1c) in the same manner as in Example 1 (144.5 mg, 0.224 mmol, yield 49%).

The NMR data, number average molecular weight, weight average molecular weight and polydispersity of the polymer represented by the formula (1c) were as follows.
¹ H-NMR (CDCl ₃ , 400 MHz): δ = 8.7-8.4 (m, 2H), 8.1 (s, 1H), 1.6-1.2 (m, 22H), 0. 856 (s, 12H)
GPC: Mn = 3900, Mw = 6100, polydispersity (Mw / Mn) = 1.56

(Example 4) [Synthesis of polymer represented by formula (1d)]

In a two-necked flask, 176.3 mg (0.237 mmol) of DTSSn2 represented by the formula (2b) as a monomer of a donor molecule was placed and filled with argon gas. Then, 81.0 mg (0.237 mmol) of PSeA represented by the formula (3a), 4.4 mg (4.80 μmol) of Pd ₂ (dba) ₃ , and 7.2 mg (23.23 of P (o-Tol) ₃ ). 7 μmol) and 10 ml of chlorobenzene were added to obtain a polymer represented by the formula (1d) in the same manner as in Example 1 (14.9 mg, 0.0248 mmol, yield 10%).

The NMR data, number average molecular weight, weight average molecular weight and polydispersity of the polymer represented by the formula (1d) were as follows.
¹ H-NMR (CDCl ₃ , 400 MHz): δ = 8.8-8.4 (m, 3H), 8.1 (s, 1H), 1.5 (Br, 2H), 1.3-1. 1 (m, 20H), 0.8 (m, 12H)
GPC: Mn = 2500, Mw = 3700, polydispersity (Mw / Mn) = 1.48

(Comparative Example 1) [Synthesis of polymer represented by formula (5)]

  An alternating copolymer of cyclopentadithiophene and pyridinothiadiazole represented by the above formula (5) was synthesized. Detailed procedures for the synthesis of the polymer represented by the above formula (5) are described in Advanced Functional Materials, 2011, Vol. 133, pages 4632-4644.

(Comparative Example 2) [Synthesis of polymer represented by formula (6)]

  An alternating copolymer of dithienogermol and benzothiadiazole represented by the above formula (6) was synthesized. Detailed procedures for the synthesis of the polymer represented by the above formula (6) are described in Organometallics, 2007, Vol. 6, pp. 497-500.

(Comparative Example 3) [Synthesis of polymer represented by formula (7)]

  An alternating copolymer of dithienosilol and benzothiadiazole represented by the above formula (7) was synthesized. The detailed procedure for synthesizing the polymer represented by the above formula (7) is described in Journal of the American Chemical Society, 2008, Vol. 130, pages 16144-16145 (Non-patent Document 2).

  The measurement of the decomposition temperature of each polymer obtained in Examples 1 and 2 and Comparative Example 1 was performed using a differential thermal-thermogravimetric simultaneous measurement apparatus (TG-DTA). Table 1 shows the temperature (decomposition temperature) at which the weight of each polymer decreases by 10%.

  As shown in Table 1, the polymer of the present invention obtained in Examples 1 and 2 has a higher decomposition temperature than the polymer obtained in Comparative Example 1, and has excellent thermal stability. Met.

  Table 2 shows the band gap (Eg) calculated from the absorption edge in the absorption spectrum of the chloroform solution of each polymer obtained in Examples 1 to 4 and Comparative Examples 2 and 3.

  As shown in Table 2, the polymers of the present invention obtained in Examples 1 to 4 have a small band gap (Eg) compared to the polymers obtained in Comparative Examples 2 and 3, and are excellent. It had a light absorption characteristic.

  The photoelectric conversion element was produced using each polymer obtained in Examples 1-4 and Comparative Examples 2 and 3, and the photoelectric conversion wavelength band of the photoelectric conversion element was measured. The photoelectric conversion element was produced by the following method.

  3.0 mg of the π-electron conjugated polymers (1a) to (1d) of the present invention obtained in Examples 1 to 4 and 10.8 mg of PC71BM (E110 manufactured by Frontier Carbon Co.) as an electron-accepting material and 2 as a solvent 0.3 mL of chlorobenzene containing 5 vol% 1,8-diiodooctane was mixed at 100 ° C. for 6 hours. Thereafter, the mixture was cooled to 20 ° C. and filtered through a PTFE filter having a pore size of 1.0 μm to prepare a composition solution containing the π-electron conjugated polymer of the present invention and PC71BM. A composition solution containing PC71BM was produced by the same method for the π-electron conjugated polymers (6) and (7) obtained in Comparative Examples 2 and 3.

  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 Co., Ltd .: CLEVIOS PH500) serving as a hole transport layer was formed on the substrate to a thickness of 40 nm by a spin coating method, and dried by heating at 140 ° C. for 20 minutes using a hot plate . Next, the composition solution was applied by spin coating and vacuum dried for 3 hours to form a photoelectric conversion layer (film thickness of about 100 nm) as a thin film. Next, lithium fluoride was vapor-deposited with a film thickness of 0.5 nm by a vacuum vapor deposition method, and then Al was vapor-deposited with a film thickness of 100 nm. Thereby, each photoelectric conversion element containing each polymer obtained in Examples 1 to 4 or Comparative Examples 2 and 3 was created. The light receiving surface shape of the photoelectric conversion element was a regular square of 5 × 5 mm.

  The photoelectric conversion wavelength band of the photoelectric conversion element produced as described above was measured under the following measurement conditions using a spectral sensitivity measuring device. The irradiation intensity at a specific wavelength at the time of measurement was calibrated using a photodiode (S1337-66BQ, manufactured by Hamamatsu Photonics). At the time of measurement, an irradiation light mask having the same area as the light receiving area of the photoelectric conversion element was worn to eliminate excessive light incidence. Table 3 shows the measurement results of the produced photoelectric conversion element.

(Measurement condition)
Apparatus: Spectral sensitivity measuring device SM-250 (manufactured by Spectrometer Co., Ltd.)
Light receiving area: 0.25 cm ²
Source meter: Keithley 2400 (manufactured by KEITHLEY)

  As shown in Table 3, the photoelectric conversion element including the π-electron conjugated polymer of the present invention obtained in Examples 1 to 4 is the photoelectric conversion element including the π-electron conjugated polymer obtained in Comparative Examples 2 and 3. Light can be absorbed to a longer wavelength side than the conversion element, and a wide photoelectric conversion wavelength band was shown. This is because when the π-electron conjugated polymer of the present invention is used, the light absorption region is wide, so that more light can be absorbed and converted into electricity, which is useful for organic devices such as photoelectric conversion elements. It shows that there is.

DESCRIPTION OF SYMBOLS 1 Organic-semiconductor layer 2 Source electrode 3 Drain electrode 4 Insulator layer 5 Gate electrode 6 Insulating support substrate 7 Gate electrode substrate 8 Gate contact 10 Organic field effect transistor 10a Organic thin-film transistor 20 Photoelectric conversion element 21 Negative electrode 22 Electron transport layer 23 Photoelectric conversion Active layer 24 Hole transport layer 25 Positive electrode 26 Substrate L Channel region

Claims (6)

The following general formula (1):

[Wherein U is Si or Ge and Y ¹ is N and Y ² is CH or CF, or Y ¹ is CH or CF and Y ² is N, Z is S, Se and N − R 1 is selected from the group consisting of R ³ , R ¹ , R ² and R ³ are each independently a hydrogen atom, a fluorine atom, a C 1-20 alkyl group which may have a substituent, It is a C6-C20 aryl group which may have a substituent, or a C4-C20 heteroaryl group which may have a substituent, and n is a positive number of 2 or more. ]
A π-electron conjugated polymer represented by   The π-electron conjugated polymer according to claim 1, wherein the number average molecular weight is 1,000 to 1,000,000 g / mol.   An organic semiconductor composition comprising the π electron conjugated polymer according to claim 1.   An organic semiconductor device comprising the π-electron conjugated polymer according to claim 1.   The organic semiconductor device according to claim 4, wherein the organic semiconductor device is an organic transistor.   It is a photoelectric conversion element, The organic-semiconductor device of Claim 4 characterized by the above-mentioned.

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