High molecular compound, method for producing high molecular compound, organic thin film solar cell material, and organic thin film solar cell

Abstract

To provide a polymer compound that has excellent photoelectric conversion efficiency, a method for producing a polymer compound, an organic thin film solar cell material and an organic thin film solar cell.SOLUTION: A polymer compound includes a repeat unit represented by formula (1). In formula (1), R1 and R2 independently represent a hydrogen atom, a halogen atom, or an alkyl group; A1 and A2 independently represent CM1 or N; M1 is a hydrogen atom, a halogen atom, or an alkyl group.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a polymer compound, a method for producing the polymer compound, an organic thin-film solar cell material, and an organic thin-film solar cell.

Background Art

[0002] A solar cell is a device that exhibits an electrical output in response to light input. Against the backdrop of the depletion problem of fossil fuels and the global warming problem, it has attracted attention as a clean energy source and has been put into practical use. So far, silicon-based solar cells have been widely put into practical use, but organic thin-film solar cells have attracted attention as a new solar cell technology because they can be manufactured by a coating process, can be made flexible, and can be made see-through. Various organic thin-film solar cell materials have been developed with the aim of improving efficiency.

[0003] As an organic thin-film solar cell material that functions as an electron donor, an electron-deficient skeleton based on naphthalene is known. Since this skeleton has a wide π-conjugation, it has been used as a building unit of a semiconductor polymer. For example, Patent Document 1 discloses a polymer compound (for example, polymer compound P1) having a structure in which two thiophene rings are bonded to a naphthodithiophene ring in a polymer main chain.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Although various organic thin-film solar cell materials have been disclosed so far, material development is still in the process of development, and there is a demand for organic thin-film solar cell materials that are more excellent in characteristics such as photoelectric conversion efficiency.

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to provide a polymer compound exhibiting good photoelectric conversion efficiency, a method for producing the polymer compound, an organic thin film solar cell material, and an organic thin film solar cell.

Means for Solving the Problems

[0007] The present inventors have intensively studied the above problems and completed the present invention. That is, the gist of the present invention is as follows.

[0008] [1] Formula (1):

Chemical formula

[0009] [2] Formula (10):

Chemical formula

Chemical formula

[0010] [3] Formula (9):

Chemical formula

[0011] [4] Formula (8):

Chemical formula

[0012] [5] Formula (7):

Chemical formula

[0013] [6] Formula (5): [Chemical formula] (In formula (5), A 1 and A 2 are each independently CM 1 or N; M 1 is a hydrogen atom, a halogen atom, or an alkyl group; R 3 is an alkyl group) and a compound represented by Formula (6): [Chemical formula] (In formula (6), X is a halogen atom) are reacted to obtain a compound represented by the above formula (7). The method for producing a polymer compound according to [5].

[0014] [7] Formula (4): [Chemical formula] (In formula (4), A 1 and A 2 are each independently CM 1 or N; M 1 is a hydrogen atom, a halogen atom, or an alkyl group; R 3 and R 5 are each independently an alkyl group) and a desilylating agent are reacted to obtain a compound represented by the above formula (5). The method for producing a polymer compound according to [6].

[0015] [8] Formula (3): [Chemical formula] (In formula (3), A 1 and A 2 are each independently CM 1 or N; M 1is a hydrogen atom, a halogen atom, or an alkyl group; R 3 is an alkyl group; Z is a halogen atom), reacting a compound represented by the formula (4) with a trialkylsilylacetylene to obtain a compound represented by the formula (4), the method for producing a polymer compound according to [7].

[0016] [9] Formula (2): [Chemical formula] (In formula (2), A 1 and A 2 are independently of each other CM 1 or N; M 1 is a hydrogen atom, a halogen atom, or an alkyl group; Z is a halogen atom), reacting a compound represented by the formula (3) with a lithium amide reagent and then reacting with a trialkylsilyl compound to obtain a compound represented by the formula (3), the method for producing a polymer compound according to [8].

[0017]

[10] I) A first step of reacting a compound represented by the formula (2) with a lithium amide reagent and then reacting with a trialkylsilyl compound to produce a compound represented by the formula (3), II) A second step of reacting the compound represented by the formula (3) obtained in the first step with a trialkylsilylacetylene to produce a compound represented by the formula (4), III) A third step of reacting the compound represented by the formula (4) obtained in the second step with a desilylating agent to produce a compound represented by the formula (5), IV) A fourth step of reacting the compound represented by the formula (5) obtained in the third step with the compound represented by the formula (6) to produce a compound represented by the formula (7), V) A fifth step of reacting the compound represented by the formula (7) obtained in the fourth step with a sulfurizing agent to produce a compound represented by the formula (8), VI) A sixth step of reacting the compound represented by the formula (8) obtained in the fifth step with a desilylating agent to produce a compound represented by the formula (9), VII) Step 7 of reacting the compound represented by the formula (9) obtained in Step 6 with a halogenating agent to produce the compound represented by the formula (10), and VIII) Step 8 of reacting the compound represented by the formula (10) obtained in Step 7 with the compound represented by the formula (11) to produce a polymer compound containing the repeating unit represented by the formula (1), the method for producing a polymer compound according to [1].

[0018]

[11] An organic thin-film solar cell material containing the polymer compound according to [1].

[0019]

[12] The organic thin-film solar cell material according to

[11] , further containing a non-fullerene-based n-type organic semiconductor material.

[0020]

[13] An organic thin-film solar cell having a photoactive layer containing the organic thin-film solar cell material according to

[11] or

[12] . [Advantages of the Invention]

[0021] According to the present invention, it is possible to provide a polymer compound, a method for producing a polymer compound, an organic thin-film solar cell material, and an organic thin-film solar cell that exhibit good photoelectric conversion efficiency. [Brief Description of the Drawings]

[0022]

Figure 1

[0023] (Polymer Compound) The polymer compound according to the present embodiment contains a repeating unit represented by the formula (1) (hereinafter referred to as "polymer compound (1)"). R in the formula (1) 1 , R 2 and M 1The number of carbon atoms of the alkyl group contained therein is preferably 6 to 30. These alkyl groups may be linear or branched, but considering film formation by a coating method such as a wet film formation method, a branched alkyl group is preferred.

[0024] The weight average molecular weight of the polymer compound (1) is preferably in the range of 10,000 to 1,000,000. Also, the number average molecular weight is preferably in the range of 10,000 to 200,000. The average molecular weight is measured by applying a polystyrene standard sample and using gel permeation chromatography (GPC) or the like. For example, the Prominence (registered trademark) GPC system of Shimadzu Corporation can be used.

[0025] (Method for producing the polymer compound (1)) The method for producing the polymer compound (1) is not particularly limited. As an example, the polymer compound (1) can be produced from commercially available compounds. Preferred steps are described along the following reaction scheme, and a more specific example is described in the examples below.

[0026]

Chemical formula

[0027] In the above formula, A 1 and A 2 are each independently CM 1 or N, M 1 is a hydrogen atom, a halogen atom, or an alkyl group, R 1 and R 2 are each independently a hydrogen atom, a halogen atom, or an alkyl group, R 3 , R 4 , and R 5 are each independently an alkyl group. Also, X, Y, and Z are each independently a halogen atom, and examples include fluorine, chlorine, bromine, and iodine. Also, n is an integer meaning a repeating unit.

[0028] <Raw material production process> A compound represented by general formula (i) (hereinafter referred to as "compound (i)") is used to produce a compound represented by general formula (2) (hereinafter referred to as "compound (2)").

[0029] In the raw material production process, compound (2) can be produced from compound (i) according to the methods described in "J. Mater. Chem. A, 1, 14538 (2013)" and "Chem. Commun. 48, 8919 (2012)". Specifically, for example, compound (i) is reacted with a halogenating agent to produce compound (2). The halogenating agent is not particularly limited as long as the reaction proceeds. Examples include N-bromosuccinimide; N-iodosuccinimide; halogens such as bromine and iodine, and halide salts thereof; etc. The halogenating agent can be used in a proportion of preferably 1 to 20 equivalents, more preferably 1 to 10 equivalents, per 1 equivalent of compound (i). The reaction in the raw material production process can usually be carried out in the presence of a solvent. The reaction temperature is usually preferably 0 to 200°C, more preferably 0 to 120°C. The reaction time is usually 1 to 48 hours. The obtained compound (2) may be purified. Also, it is preferable to purify compound (2) before subjecting it to the following first step.

[0030] <First Step> Next, a compound represented by the general formula (3) (hereinafter referred to as "compound (3)") is produced from compound (2) (the first step). Specifically, the first step is a step of reacting compound (2) with a lithium amide reagent and then reacting with a trialkylsilyl compound to produce compound (3). Examples of the lithium amide reagent include lithium diisopropylamide, lithium 2,2,6,6-tetramethylpiperidide, and lithium hexamethyldisilazide. Examples of the trialkylsilyl compound include trialkylsilyl chlorides such as tert-butyldimethylsilyl chloride; trialkylchlorosilanes such as trimethylchlorosilane, trimethylmethoxysilane, and triethylethoxysilane; and the like. The reaction can be carried out in the presence of a solvent as necessary. Any solvent that is inert to the reaction may be used. For example, an amine base such as 2,2,6,6-tetramethylpiperidineamine; an aprotic polar solvent such as N,N-dimethylformamide or acetonitrile; an ether such as tetrahydrofuran (THF); and the like. One or more of these can be appropriately selected. The reaction temperature is usually preferably from -78°C to 50°C, more preferably from -40°C to 40°C. The reaction time is usually from 0.5 to 48 hours. The obtained compound (3) may be purified. Also, it is preferable to purify compound (3) before subjecting it to the second step described below.

[0031] <Second step> Next, a compound represented by the general formula (4) (hereinafter referred to as "compound (4)") is produced from compound (3) (the second step). Specifically, the second step is a step of reacting compound (3) with trialkylsilylacetylene to obtain compound (4).

[0032] For example, compound (3) can react with trialkylsilylacetylene in the presence of a catalyst to produce compound (4). Trialkylsilylacetylene is not particularly limited as long as the reaction proceeds. Examples thereof include trimethylsilylacetylene and triethylsilylacetylene. Trialkylsilylacetylene can be used in a ratio of preferably 2 to 20 equivalents, more preferably 2 to 10 equivalents, per 1 equivalent of compound (3). Examples of the catalyst include tetrakis(triphenylphosphine)palladium (Pd(PPh3)4), bis(triphenylphosphine)palladium(II) dichloride (Pd(PPh3)2Cl2), tris(dibenzylideneacetone)dipalladium(0) (Pd2(dba)3), and copper(I) iodide (CuI). As the ligand, triphenylphosphine or tri(o-tolyl)phosphine may be added. The reaction in the second step can usually be carried out in the presence of a base and a solvent. The base is not particularly limited as long as the reaction proceeds. The base can be used in a ratio of preferably 1 to 40 equivalents, more preferably 1 to 20 equivalents, per 1 equivalent of compound (3). As the solvent, any solvent that is inert to the reaction may be used. For example, ethers such as tetrahydrofuran (THF); solvents that also function as bases, such as triethylamine and piperidine; etc. One or more of these can be appropriately selected. The reaction temperature is usually preferably 0 to 200°C, more preferably 0 to 120°C. The reaction time is usually 1 to 48 hours. Compound (4) is preferably purified before being subjected to the following third step.

[0033] <Step 3> Next, compound (4) is used to produce a compound represented by general formula (5) (hereinafter referred to as "compound (5)") (the third step). Specifically, the third step is a step of reacting compound (4) with a desilylating agent to obtain compound (5). As the desilylating agent, it is preferable to use an inorganic base. Examples of the inorganic base include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; carbonates such as potassium carbonate and cesium carbonate; and the like. As the solvent, for example, one or more selected and mixed from alcohols such as methanol, ethanol, and 2-propanol; aliphatic halogenated hydrocarbons such as dichloromethane and chloroform; and the like can be appropriately used. The reaction temperature is usually preferably 0 to 200°C, more preferably 0 to 120°C. The reaction time is usually 1 to 48 hours. The obtained compound (5) may be purified. Further, it is preferable to purify compound (5) before subjecting it to the following fourth step.

[0034] <Fourth Step> Next, compound (5) is used to produce a compound represented by general formula (7) (hereinafter referred to as "compound (7)") (the fourth step).

[0035] The fourth step is specifically a step of reacting compound (5) with a compound represented by general formula (6) (hereinafter referred to as "compound (6)") to produce compound (7). The raw material compound (6) can be synthesized based on "S. Mataka et al., Bull. Chem. Soc. Jpn., 64, 68 (1991)". Compound (5) and compound (6) are put into a solvent, and a catalyst is added for reaction. Examples of the catalyst include tetrakis(triphenylphosphine)palladium (Pd(PPh3)4), bis(triphenylphosphine)palladium(II) dichloride (Pd(PPh3)2Cl2), tris(dibenzylideneacetone)dipalladium(0) (Pd2(dba)3), copper(I) iodide (CuI), etc. Any solvent that is inert to the reaction can be used as the solvent. For example, ethers such as tetrahydrofuran (THF); solvents that also function as bases, such as triethylamine and piperidine; etc. One or more of them can be appropriately selected. The reaction temperature is usually preferably 0 to 200 °C, more preferably 0 to 120 °C. The reaction time is usually 1 to 48 hours. Compound (7) is preferably purified before being subjected to the following fifth step.

[0036] <The fifth step> Next, compound (8) represented by general formula (8) (hereinafter referred to as "compound (8)") is produced from compound (7) (the fifth step).

[0037] The fifth step is specifically a step of producing compound (8) by reacting compound (7) with a sulfurizing agent. The sulfurizing agent is not particularly limited as long as it is a sulfurizing agent that allows the reaction to proceed. Examples thereof include sulfur, sulfur monochloride, sulfur dichloride, thionyl chloride, sulfuryl chloride, 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide, and the like. As the sulfurizing agent, a ratio of 1 to 20 equivalents, more preferably 2 to 5 equivalents, can be used per 1 equivalent of compound (7). The reaction in the fifth step can usually be carried out in the presence of a base and a solvent. The base is not particularly limited as long as it is a base that allows the reaction to proceed. The base can be used in a ratio of 1 to 20 equivalents, more preferably 2 to 10 equivalents, per 1 equivalent of compound (7). The solvent is not particularly limited as long as it is a solvent that allows the reaction to proceed. The reaction temperature is usually preferably 0 to 250°C, more preferably 0 to 200°C. The reaction time is usually 1 to 48 hours. Compound (8) is preferably purified before being subjected to the sixth step.

[0038] <Sixth Step> Next, compound (9) represented by the general formula (9) (hereinafter referred to as "compound (9)") is produced from compound (8) (sixth step).

[0039] Step 6 is specifically a step of reacting compound (8) with a desilylating agent to produce compound (9). Examples of the desilylating agent include inorganic bases; metal alkoxides; fluorides; and the like. The desilylating agent may be used alone or in combination of two or more. Also, commercially available desilylating agents can be used. Examples of the inorganic base include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, potassium carbonate, cesium carbonate, and the like. Examples of the metal alkoxide include sodium tert-butoxide, potassium tert-butoxide, sodium methoxide, potassium methoxide, sodium ethoxide, potassium ethoxide, sodium trimethylsilyloxide, and potassium trimethylsilyloxide. Examples of the fluoride include trifluoroacetic acid, pyridine hydrofluoride, potassium fluoride, cesium fluoride, tetra-n-butylammonium fluoride, and the like. The amount of the desilylating agent used can be preferably 1 to 10 equivalents, more preferably 1 to 5 equivalents, relative to 1 equivalent of compound (8).

[0040] Examples of the solvent used as needed in the desilylation reaction include aliphatic halogenated hydrocarbons such as dichloromethane and chloroform; aprotic polar solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpropionamide, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, and hexamethylphosphoric triamide; ether solvents such as tetrahydrofuran, diethyl ether, and 4-methyltetrahydropyran; primary alcohols having 1 to 4 carbon atoms such as methanol, ethanol, 1-propanol, and 1-butanol; secondary alcohols such as isopropyl alcohol; tertiary alcohols such as tert-butyl alcohol; and the like.

[0041] The reaction temperature in the desilylation reaction is preferably 0 to 150°C, more preferably 25 to 80°C. The reaction time in the desilylation reaction is usually 1 to 48 hours. Compound (9) is preferably purified before being subjected to Step 7.

[0042] <Step 7> Next, a compound represented by the general formula (10) (hereinafter referred to as "compound (10)") is produced from compound (9) (Step 7).

[0043] Specifically, Step 7 is a step of producing compound (10) by reacting compound (9) with a halogenating agent. The halogenating agent is not particularly limited as long as the reaction proceeds. Examples thereof include N-bromosuccinimide, N-iodosuccinimide; halogens such as bromine and iodine, and halide salts thereof; and the like. The halogenating agent can be used in a proportion of preferably 2 to 20 equivalents, more preferably 2 to 10 equivalents, relative to 1 equivalent of compound (9). The reaction of Step 7 can usually be carried out in the presence of a solvent. The reaction temperature is usually preferably 0 to 200°C, more preferably 0 to 120°C. The reaction time is usually 1 to 48 hours. Also, it is preferable to purify compound (10) before subjecting it to the following Step 8.

[0044] <Step 8> Next, a polymer compound (1) is produced from compound (10) and a compound represented by the general formula (11) (hereinafter referred to as "compound (11)") (Step 8). Compound (11) can be synthesized with reference to "Advanced Materials, 27, 4655, (2015)".

[0045] The eighth step is specifically a step of producing the polymer compound (1) by reacting the compound (10) with the compound (11). The compound (10) and the compound (11) are reacted in the presence of a catalyst in a solvent. Examples of the solvent include toluene, chlorobenzene, dimethylformamide (DMF), tetrahydrofuran (THF), and the like. Examples of the catalyst include tetrakis(triphenylphosphine)palladium (Pd(PPh3)4), bis(triphenylphosphine)palladium(II) dichloride (Pd(PPh3)2Cl2), tris(dibenzylideneacetone)dipalladium(0) (Pd2(dba)3), and the like. The reaction temperature can be, for example, 80°C to 200°C. The obtained polymer compound (1) may be purified. In this way, the polymer compound (1) of the present invention can be produced.

[0046] (Organic thin-film solar cell material) The polymer compound (1) can be used as an organic thin-film solar cell material. The organic thin-film solar cell material can form a photoactive layer of an organic solar cell by a coating method such as a wet film-forming method. The polymer compound (1) functions as an electron donor as a so-called p-type organic semiconductor.

[0047] The organic thin-film solar cell material may contain only the polymer compound (1) or may contain other organic solar cell materials and other components. The organic thin-film solar cell material preferably contains an electron-accepting compound that functions as an electron acceptor. The electron-accepting compound may be a compound that functions as a so-called n-type organic semiconductor material, and known compounds are used.

[0048] The organic thin-film solar cell material may contain only the polymer compound (1), or may contain other organic solar cell materials and other components. The organic thin-film solar cell material preferably contains an electron-accepting compound that exhibits a function as an electron acceptor. The electron-accepting compound may be any substance that functions as a so-called n-type organic semiconductor material, and known substances can be used. For example, fullerene-based materials and non-fullerene-based compounds can be mentioned. Mixing a non-fullerene-based compound with the polymer compound (1) to form a photoactive layer is preferable because excellent photoelectric conversion efficiency can be obtained. Examples of the non-fullerene-based compound include the following compounds. Y6 (2,2’-((2Z,2’Z)-((12,13-bis(2-ethylhexyl)-3,9-didodecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2’’,3’’:4’,5’]thieno[2’,3’:4,5]pyrrolo[3,2-g]thieno[2’,3’:4,5]thieno[3,2-b]indole-2,10-diyl)bis(methylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile) Y6-5 (12,13-bis(2-ethylhexyl)-3,9-didodecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2’’,3’’:4’,5’]thieno[2’,3’:4,5]pyrrolo[3,2-g]thieno[2’,3’:4,5]thieno[3,2-b]indole-2,10-dicarbaldehyde) Y7 (2,2’-((2Z,2’Z)-((12,13-bis(2-ethylhexyl)-3,9-didodecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2’’,3’’:4’,5’]thieno[2’,3’:4,5]pyrrolo[3,2-g]thieno[2’,3’:4,5]thieno[3,2-b]indole-2,10-diyl)bis(methylidene))bis(5,6-dichloro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile) Y12(2,2'-((2Z,2'Z)-((12,13-bis(2-butyloctyl)-3,9-didodecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2'',3'':4',5']thieno[2',3':4,5]pyrrolo[3,2-g]thieno[2',3':4,5]thieno[3,2-b]indole-2,10-diyl)bis(methylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-2,1-diylidene))dimalononitrile) BTP-eC9(2,2'-[[12,13-bis(2-butyloctyl)-12,13-dihydro-3,9-dinonyldithieno[2'',3'':4',5']thieno[2',3':4,5]pyrrolo[3,2-e:2',3'-g][2,1,3]benzothiadiazolo-2,10-diyl]bis[methylidene(5,6-chloro-3-oxo-1H-inden-2,1(3H)-diylidene)]]bis[propanedinitrile]) IT-4F(3,9-bis(2-methylene-((3-1,1-dicyanomethylene)-6,7,-difluoro)-indanone))-5,5,11,11,-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2',3'-d']-s-indaceno[1,2-b:5,6-b']dithiophene)

[0049] (Organic thin-film solar cell) The organic thin-film solar cell uses the above-mentioned organic thin-film solar cell material for the photoactive layer. The structure of the organic thin-film solar cell is not particularly limited as long as it has a structure with a photoactive layer between a pair of electrodes. Examples of the configuration of the organic thin-film solar cell include the following aspects. Here, the p-layer and p-material refer to the layer and material containing the above-mentioned organic thin-film solar cell material, and the n-layer and n-material refer to the layer and material containing the above-mentioned electron-accepting compound. (A) Electrode / Mixed layer of p-material and n-material / Electrode (B) Electrode / p-layer / Mixed layer of p-material and n-material / n-layer / Electrode (C) Electrode / p-layer / n-layer / Electrode

[0050] Since the polymer compound (1) has a structure with an extended π-conjugated system, it has strong intermolecular interactions and high crystallinity. For these reasons, when used in the photoactive layer of an organic thin-film solar cell, characteristics such as the photoelectric conversion efficiency are good.

Example

[0051] Hereinafter, based on the examples, the synthesis, physical properties of a polymer compound (organic semiconductor material) having dithieno[3,2-b:2',3'-d]naphtho[2,1-f][1,3,2]thiadiazole (TNT), and the characteristics of an organic thin-film solar cell will be described. The present invention is not limited to these examples.

[0052] <Synthesis Example 1> (Synthesis of Compound 2) 2-Bromo-3-(2-hexyldecyl)thiophene (Compound 1) was synthesized in advance with reference to "J. Mater. Chem. A, 1, 14538 (2013)" and "Chem. Commun. 48, 8919 (2012)". 2,2,6,6-Tetramethylpiperidine (3.67 g, 26 mmol) and tetrahydrofuran (25 mL) were placed in a 100 mL eggplant flask, cooled to 0 °C, and n-butyllithium (15 mL, 24 mmol) was added dropwise, followed by stirring for 30 minutes. Compound 1 (9.03 g, 20 mmol) was slowly added dropwise to the reaction solution, and stirring was continued at 0 °C for 30 minutes. Then, tert-butyldimethylsilyl chloride was added, and the mixture was stirred at room temperature for 2 hours. Water (30 mL) was added to the reaction solution to quench it, and extraction was performed 3 times with hexane (10 mL). The organic layer was washed with brine (30 mL) and water (30 mL) respectively, and dried over anhydrous sodium sulfate. Then, filtration and concentration were carried out, and purification by silica gel column chromatography using hexane as the developing solvent gave Compound 2 (9.13 g, 18.2 mmol, yield 91%). The reaction formula is shown below.

[0053]

Chemical formula

[0054] The physical property data of Compound 2 are as follows.1 1H NMR (400 MHz, CDCl3): δ 6.86 (s, 1H), 2.49 (d, 2H), 1.64 (m, 1H), 1.30 - 1.23 (m, 24H), 0.87 (t, 6H).

[0055] <Synthesis Example 2> (Synthesis of Compound 3) Under an argon atmosphere, into a 100 mL three-necked flask equipped with a reflux tube, Compound 2 (10.0 g, 19.1 mmol), copper(I) iodide (0.18 g, 0.957 mmol), triphenylphosphine (0.3 g, 1.15 mmol), and trimethylsilylacetylene (2.82 g, 28.7 mmol) were added. A mixed solvent of triethylamine (20 mL) and tetrahydrofuran (20 mL) was added, and the mixture was degassed with argon for 30 minutes. Subsequently, tetrakis(triphenylphosphine)palladium was added as a catalyst, and the mixture was stirred at 90 °C for 12 hours. Thereafter, the reaction solution was concentrated and purified by silica gel column chromatography using hexane as the developing solvent to obtain Compound 3 (10.0 g, 18.3 mmol, yield 95%). The reaction formula is shown below.

[0056] [Chemical formula]

[0057] The physical property data of Compound 3 are as follows. 1 1H NMR (400 MHz, CDCl3): δ 6.88 (s, 1H), 2.61 (d, 2H), 1.69 (m, 1H), 1.35 - 1.20 (m, 24H), 0.89 (m, 15H), 0.26 (s, 6H), 0.23 (s, 9H).

[0058] <Synthesis Example 3> (Synthesis of Compound 4) In a 100 mL three-necked flask equipped with a reflux tube under an argon atmosphere, a mixed solvent of compound 3 (10.4 g, 19 mmol), dichloromethane (20 mL), and methanol (20 mL) was added. Potassium carbonate (2.9 g, 20.9 mmol) was added, and the mixture was stirred for 12 hours. Water (50 mL) was added to the reaction solution, and the mixture was extracted three times with dichloromethane (10 mL). The organic layer was washed with brine (30 mL) and water (30 mL) respectively, and dried over anhydrous sodium sulfate. Then, filtration and concentration were performed, and compound 4 (7.9 g, 17.7 mmol, yield 93%) was obtained by purification using silica gel column chromatography with hexane as the developing solvent. The reaction formula is shown below.

[0059] [Chemical formula]

[0060] The physical property data of compound 4 are as follows. 1 H NMR (400 MHz, CDCl3): 1 H NMR (400 MHz, CDCl3): δ 6.91 (s, 1H), 3.47 (s, 1H), 2.63 (d, 2H), 1.68 (m, 1H), 1.35 - 1.20 (m, 24H), 0.89 (m, 15H), 0.27 (s, 6H).

[0061] <Synthesis Example 4> (Synthesis of Compound 6) 5,10-Dibromonaphtho[1,2-c:5,6-c']bis([1,2,5]thiadiazole) (Compound 5) was synthesized in advance with reference to "Bull. Chem. Soc. Jpn., 64, 68 (1991)". Under an argon atmosphere, into a 200 mL three-necked flask connected with a reflux tube were added Compound 4 (3.7 g, 7.3 mmol), Compound 5 (1.2 g, 2.9 mmol), copper(I) iodide (27.8 mg, 0.15 mmol), and triphenylphosphine (168.7 mg, 0.15 mmol). A mixed solvent of triethylamine (20 mL) and tetrahydrofuran (20 mL) was added, degassed with argon for 30 minutes, and tetrakis(triphenylphosphine)palladium was added as a catalyst, followed by stirring at 90 °C for 12 hours. The reaction solution was filtered through celite, concentrated, and then purified by silica gel column chromatography using a mixed solvent of dichloromethane:hexane (gradient from 1:50 to 1:5) as the developing solvent to obtain Compound 6 (2.1 g, 1.87 mmol, yield 64%). The reaction formula is shown below.

[0062] [Chemical formula]

[0063] The physical property data of Compound 6 are as follows. 1 H NMR (400 MHz, CDCl3): δ 8.98 (s, 2H), 7.02 (s, 2H), 2.87 (d, 4H), 1.83 (m, 2H), 1.40 - 1.13 (m, 48H), 0.95 (s, 9H), 0.80 - 0.89 (m, 12H), 0.33 (s, 6H).

[0064] [Synthesis Example 5] (Synthesis of Compound 7) Compound 6 (2.0 g, 1.76 mmol), sulfur (1.8 g, 7.1 mmol), and N,N-dimethylacetamide (26 mL) were placed in a reaction vial and sealed. Using a microwave reactor, the reaction was carried out at 200 °C for 45 minutes. Then, it was cooled to room temperature, water was added to the reaction solution, and the mixture was extracted three times with chloroform. The organic layer was washed with brine and dried over anhydrous magnesium sulfate. Then, filtration and concentration were performed, and purification was carried out by silica gel column chromatography using a dichloromethane:hexane (gradient from 1:50 to 1:5) mixed solvent as the developing solvent to obtain Compound 7 (833 mg, 0.72 mmol, yield 41%). The reaction scheme is shown below.

[0065] [Chemical Formula]

[0066] The physical property data of Compound 7 are as follows. 1 H NMR (400 MHz, CDCl3): δ 8.20 (s, 2H), 7.12 (s, 2H), 2.96 (d, 4H), 1.82 (m, 2H), 1.35 - 1.10 (m, 48H), 1.00 (s, 9H), 0.78 - 0.83 (m, 12H), 0.36 (s, 6H).

[0067] [Synthesis Example 6] (Synthesis of Compound 8) Compound 7 (0.83 g, 0.71 mmol) was dissolved in dichloromethane (30 mL), then trifluoroacetic acid (10 mL) was added, and the mixture was stirred at room temperature for 2 hours. A saturated aqueous sodium bicarbonate solution was added to the reaction solution to quench it, and the mixture was extracted three times with dichloromethane. The organic layer was washed with brine and dried over anhydrous magnesium sulfate. Then, the solvent was distilled off, and purification was carried out by silica gel column chromatography using chloroform as the developing solvent, followed by recrystallization using a chloroform / ethanol mixed solvent to obtain Compound 8 (0.66 g, 0.71 mmol, yield 99%). The reaction scheme is shown below.

[0068] [Chemical formula]

[0069] The physical property data of Compound 8 are as follows. 1 H NMR (400 MHz, CDCl3): δ 8.12 (s, 2H), 7.36 (d, 2H), 7.03 (d, 2H), 2.94 (d, 4H), 2.19 (m, 2H), 1.35 - 1.10 (m, 48H), 0.75 - 0.84 (m, 12H).

[0070] [Synthesis Example 7] (Synthesis of Compound 9) Under an argon atmosphere, Compound 10 (0.66 g, 0.71 mmol) was placed in a 100 mL three-necked flask, dissolved in 20 mL of chloroform, and then N-bromosuccinimide (394.5 mg, 2.22 mmol) was added, followed by stirring at room temperature for 6 hours. A saturated aqueous sodium hydrogen carbonate solution was added to the reaction solution to quench it, and the mixture was extracted three times with chloroform. The organic layer was washed with brine and dried over anhydrous magnesium sulfate. Then, the solvent was distilled off, and purification was performed by silica gel column chromatography using chloroform as the developing solvent, followed by recrystallization using a chloroform / ethanol mixed solvent, to obtain Compound 9 (0.78 g, 0.71 mmol, yield 99%). The reaction formula is shown below.

[0071] [Chemical formula]

[0072] The physical property data of Compound 9 are as follows. 1 H NMR (400 MHz, CDCl3): δ 7.97 (s, 2H), 6.97 (s, 2H), 2.85 (d, 4H), 1.74 (m, 2H), 1.35 - 1.10 (m, 48H), 0.80 - 0.90 (m, 12H).

[0073] [Synthesis Example 8] (Synthesis of Polymer Compound P1) 4,8-Bis(5-(2-ethylhexyl)-4-fluorothiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene-2,6-diyl)bis(trimethylstannane) (Compound 10) was synthesized in advance with reference to "Adv. Mater., 27, 4655, (2015)". Compound 9 (33.8 mg, 0.03 mmol), Compound 10 (28.2 mg, 0.03 mmol), tris(dibenzylideneacetone)(chloroform)dipalladium(0) (0.32 mg, 0.0003 mol), tri(o-tolyl)phosphine (1.22 mg, 0.008 mol), and toluene (2 mL) were placed in a reaction vial, sealed with nitrogen, and tightly capped. Using a microwave reactor, the reaction was carried out at 140 °C for 1 hour. After cooling to room temperature, the reaction solution was poured into a 5% hydrochloric acid / methanol solution and stirred for 3 hours. The precipitated solid was collected by filtration, washed with methanol, n-hexane, and dichloromethane using a Soxhlet extractor, and then extracted with chloroform. The obtained solution was concentrated and reprecipitated in methanol to obtain the polymer compound P1 (45 mg, yield 95%) as a shiny black solid (number average molecular weight 77,000). The reaction formula is shown below.

[0074]

Chemical formula

[0075] Examples of the polymer compound (1) include the compounds shown in Table 1 below. In the table, C-2-hexyldecyl represents a 2-hexyldecyl group bonded to a carbon atom, C-2-butyloctyl represents a 2-butyloctyl group bonded to a carbon atom, C-2-decyltetradecyl represents a 2-decyltetradecyl group bonded to a carbon atom, 2-ethylhexyl represents a 2-ethylhexyl group bonded to a carbon atom, and C-H represents a hydrogen atom bonded to a carbon atom, respectively. These compounds can be produced according to the production method of the aforementioned polymer compound (1) and the description of the examples.

[0076]

Table 1

[0077] Next, a solar cell device was fabricated using the synthesized polymer compound P1, and the photoelectric conversion efficiency was evaluated.

[0078] (Evaluation of Solar Cell Device Using Polymer Compound P1) After thoroughly cleaning a glass substrate with a patterned ITO film, UV ozone treatment was performed. Next, an aqueous solution of PEDOT (poly(3,4-ethylenedioxythiophene)):PSS (polystyrene sulfonic acid) was spin-coated at 5000 rpm for 30 seconds (thickness: approximately 40 nm). By heating the substrate at 120 °C for 10 minutes, a hole extraction layer was formed. The substrate with the hole extraction layer formed was brought into a glove box, and a chloroform solution containing the polymer compound P1 and the n-type low-molecular material Y6 (2,2'-((2Z,2'Z)-((12,13-bis(2-ethylhexyl)-3,9-didodecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2'',3'':4',5']thieno[2',3':4,5]pyrrolo[3,2-g]thieno[2',3':4,5]thieno[3,2-b]indole-2,10-diyl)bis(methylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile) (weight ratio of polymer compound P1 / Y6 = 1 / 1.2) was used to form a photoactive layer by spin coating (film thickness: 150 nm). Further, as an electron extraction layer on the active layer, a PDINO (2,9-bis[3-(dimethyl oxide amino)propyl]anthra [2,1,9-def:6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetrone) film was spin-coated at 3000 rpm for 30 seconds (thickness: approximately 20 nm). Next, a silver film with a thickness of 220 nm was sequentially formed as an electrode layer by resistance heating type vacuum evaporation method to fabricate an organic thin film solar cell device with a diameter of 4 mm. The chemical formulas of Y6 and PDINO are shown below.

[0079] [Chemical Formula]

[0080] The obtained organic thin-film solar cell was irradiated with constant light using a solar simulator (AM1.5G filter, irradiance 100 mW / cm 2 ), and the generated current and voltage were measured. A graph of the current density-voltage characteristics is shown in Fig. 1.

[0081] From the obtained Fig. 1, the short-circuit current density Jsc (mA / cm -2 ), open-circuit voltage Voc (V), and fill factor FF were determined and summarized in Table 2. For P1, Jsc = 26.0 mA / cm 2 , Voc = 0.86 V, and FF = 0.65. When the photoelectric conversion efficiency (η) was calculated from the formula η = (Jsc × Voc × FF) / 100, it was 14.6%.

[0082]

Table 2

Industrial Applicability

[0083] The polymer compound according to the present invention can be used as an organic thin-film solar cell material for forming the photoactive layer of an organic thin-film solar cell. cell.

Claims

1. Formula (1): 【Chemical 1】 (In formula (1), R １ and R ２ are each independently a hydrogen atom, a halogen atom, or an alkyl group; A １ is CM １ (where M １ is an alkyl group); A2 is CH), a polymer compound containing a repeating unit represented by the formula.

2. Formula (10): 【Chemical Formula 2】 (In formula (10), A １ is CM １ (provided that M １ is an alkyl group); A2 is CH; Y is a halogen atom), and a compound represented by formula (11): 【Chemical Formula 3】 (In formula (11), R １ and R ２ are each independently a hydrogen atom, a halogen atom, or an alkyl group; R ４ is an alkyl group), the method for producing a polymer compound according to claim 1, comprising the step of reacting a compound represented by the formula.

3. Formula (9): 【Chemical 4】 (In formula (9), A １ is CM １ (wherein M １ is an alkyl group); A2 is CH), and reacting the compound represented by the formula with a halogenating agent to obtain the compound represented by the formula (10). The method for producing a polymer compound according to claim 2, comprising the step of

4. Formula (8): 【Chemical Formula 5】 (In formula (8), A １ is CM １ (wherein M １ is an alkyl group); A2 is CH; R ３ is an alkyl group), reacting the compound represented by the formula with a desilylating agent to obtain the compound represented by the formula (9), the method for producing a polymer compound according to claim 3.

5. Formula (7): 【Chemical Formula 6】 (In formula (7), A １ is CM １ (provided that M １ is an alkyl group); A2 is CH; R ３ is an alkyl group), reacting a compound represented by the formula with a sulfurizing agent to obtain a compound represented by the formula (8), the method for producing a polymer compound according to claim 4.

6. Formula (5): 【Chemical Formula 7】 (In formula (5), A １ is CM １ (provided that M １ is an alkyl group); A2 is CH; R ３ is an alkyl group), and a compound represented by Formula (6): 【Chemical Formula 8】 (In formula (6), X is a halogen atom), and reacting the compound represented thereby to obtain a compound represented by the said formula (7), the manufacturing method of the high molecular compound according to Claim 5.

7. Formula (4): 【Chemical Formula 9】 (In formula (4), A １ is CM １ (wherein M １ is an alkyl group); A2 is CH; R ３ and R ５ are each independently an alkyl group), reacting a compound represented by the formula with a desilylating agent to obtain a compound represented by the formula (5), the method for producing a polymer compound according to claim 6.

8. Formula (3): 【Chemical Formula 10】 (In formula (3), A １ is CM １ (wherein M １ is an alkyl group); A2 is CH; R ３ is an alkyl group; Z is a halogen atom), reacting a compound represented by the formula with trialkylsilylacetylene to obtain a compound represented by the formula (4), the method for producing a polymer compound according to claim 7.

9. Formula (2): 【Chemical Formula 11】 (In formula (2), A １ is CM １ (wherein M １ is an alkyl group); A2 is CH; Z is a halogen atom)), reacting the resulting compound with a lithium amide reagent and then reacting with a trialkylsilyl compound to obtain the compound represented by the formula (3), the method for producing a polymer compound according to claim 8, comprising the step of

10. I) Formula (2): 【Chemical 12】 (In formula (2), A1 is CM1 (where M1 is an alkyl group); A2 is CH; Z is a halogen atom), reacting the compound represented thereby with a lithium amide reagent, and then reacting with a trialkylsilyl compound to obtain a compound represented by formula (3): 【Chemical 13】 (In formula (3), A1 is CM1 (where M1 is an alkyl group); A2 is CH; R3 is an alkyl group; Z is a halogen atom), the first step of manufacturing a compound represented thereby. II) Reacting the compound represented by the said formula (3) obtained in the first step with a trialkylsilylacetylene to obtain a compound represented by formula (4): 【Chemical 14】 (In formula (4), A1 is CM1 (where M1 is an alkyl group); A2 is CH; R3 and R5 are each independently an alkyl group), the second step of manufacturing a compound represented thereby. III) Reacting the compound represented by the said formula (4) obtained in the second step with a desilylating agent to obtain a compound represented by formula (5): 【Chemical Formula 15】 (In formula (5), A1 is CM1 (where M1 is an alkyl group); A2 is CH; R3 is an alkyl group), the third step of manufacturing a compound represented thereby. IV) Reacting the compound represented by the said formula (5) obtained in the third step with a compound represented by formula (6): 【Chemical Formula 16】 (In formula (6), X is a halogen atom) to obtain a compound represented by formula (7): 【Chemical 17】 (In formula (7), A1 is CM1 (where M1 is an alkyl group); A2 is CH; R3 is an alkyl group), the fourth step of manufacturing a compound represented thereby. V) Reacting the compound represented by the said formula (7) obtained in the fourth step with a sulfurizing agent to obtain a compound represented by formula (8): 【Chemical Formula 18】 (In formula (8), A1 is CM1 (where M1 is an alkyl group); A2 is CH; R3 is an alkyl group), the fifth step of manufacturing a compound represented thereby. VI) Reacting the compound represented by the formula (8) obtained in the fifth step with a desilylating agent to obtain a compound represented by the formula (9): 【Chemical Formula 19】 (In the formula (9), A1 is CM1 (where M1 is an alkyl group); A2 is CH) The sixth step of producing a compound represented by, VII) Reacting the compound represented by the formula (9) obtained in the sixth step with a halogenating agent to obtain a compound represented by the formula (10): 【Chemical 20】 (In the formula (10), A1 is CM1 (where M1 is an alkyl group); A2 is CH; Y is a halogen atom) The seventh step of producing a compound represented by, and VIII) Reacting the compound represented by the formula (10) obtained in the seventh step with a compound represented by the formula (11): 【Chemical 21】 (In the formula (11), R1 and R2 are each independently a hydrogen atom, a halogen atom, or an alkyl group; R4 is an alkyl group) The method for producing a polymer compound containing the repeating unit represented by the formula (1) according to claim 1, which includes the eighth step of producing a polymer compound containing the repeating unit represented by the formula (1).

11. An organic thin-film solar cell material containing the polymer compound according to claim 1.

12. The organic thin-film solar cell material according to claim 11, further containing a non-fullerene-based n-type organic semiconductor material.

13. An organic thin-film solar cell having a photoactive layer containing the organic thin-film solar cell material according to claim 11 or 12.

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