JP5377120B2 - Photoelectric conversion element and manufacturing method thereof - Google Patents

Description

  The present invention relates to a photoelectric conversion element and a manufacturing method thereof.

  Photoelectric conversion elements such as dye-sensitized solar cells are expected as photoelectric conversion elements that can exhibit high photoelectric conversion efficiency. The structure of the dye-sensitized solar cell includes a working electrode composed of a porous oxide layer of oxide semiconductor such as titanium dioxide on which a photosensitizing dye is supported on a transparent electrode substrate such as ITO, and is opposed to this working electrode. The structure includes a counter electrode having tin-containing indium oxide (ITO) and carbon arranged, and an electrolyte layer between the working electrode and the counter electrode.

However, an electrode on which a metal oxide such as ITO constituting the working electrode and counter electrode of the dye-sensitized solar cell is formed has a problem that a film forming process by vapor deposition is required and the manufacturing cost is expensive.
In particular, when a conductive electrode substrate such as glass or film having platinum supported on the counter electrode or a metal substrate is used as in the past, platinum is expensive, and vacuum process such as sputtering is one of the film forming methods. In some cases, the manufacturing cost becomes very high. Further, when an electrode having a platinum film is used as a counter electrode, the platinum film may be detached and dissolved during long-term use, and power generation characteristics may deteriorate.

  On the other hand, when a paste containing carbon powder is applied to a substrate and baked to produce a counter electrode, if baked at a high temperature, the carbon may be oxidized or the substrate may be deteriorated. . Therefore, there exists a fault that the adhesive force of a board | substrate and carbon and carbon particle and carbon particle is low. In some cases, a paste containing an organic binder or the like is used to increase the adhesion, but the binder remains in the produced porous carbon electrode, so that the area of carbon effective for the electrode reaction is reduced. Yes (Patent Document 1).

  There has also been a proposal for producing a long-term stable counter electrode by electrodepositing a carbon nanotube solution on a substrate (Patent Document 2). However, since carbon nanotubes are simply mixed in an organic solvent, there is a problem that the carbon nanotubes are not sufficiently dispersed, and therefore sufficient conductivity is not exhibited. Moreover, an electrodeposition process is required, and the manufacturing process is complicated and expensive.

  Since carbon nanotubes were discovered by Iijima et al. In 1991 (Non-patent Document 1), their physical properties have been evaluated and their functions have been elucidated, and research and development relating to their applications have been actively conducted. However, since carbon nanotubes are manufactured in an entangled state, there is a problem that handling becomes very complicated. When mixed in a resin or solution, the carbon nanotubes further aggregate, and there is a problem that the original characteristics of the carbon nanotubes cannot be expressed.

  In order to improve the dispersibility of such carbon nanotubes, a composition containing carbon nanotubes and a water-soluble conductive polymer, and a conductor produced from the composition have been proposed, and include such organisms. It has been shown that the solution has excellent dispersibility and excellent long-term storage stability in a solution state (Patent Document 3).

Japanese Patent Laid-Open No. 2004-127849 JP 2008-66018 A International Publication No. 2004/039893 Pamphlet

S. Iijima, Nature, 354, 56 (1991)

  However, no proposal has been made to use the composition described in Document 3 for a photoelectric conversion element such as a dye-sensitized solar cell. There is also a need for a photoelectric conversion element that is highly efficient and has excellent long-term stability of photoelectric conversion efficiency.

  This invention is made | formed in view of the said situation, and it aims at providing the photoelectric conversion element excellent in high efficiency and long-term stability, and its manufacturing method.

In order to solve the above problems, the first of the present invention is a working electrode having an oxide semiconductor porous film layer carrying a dye supported on at least a part of a conductive layer formed on a substrate, and the action A photoelectric conversion element comprising a counter electrode disposed opposite to an electrode and having a conductive layer formed on a substrate, and an electrolyte layer between the working electrode and the counter electrode, wherein the working electrode and / or or counter electrode conductive layer, water-soluble electroconductive polymer having a sulfonic acid group and / or carboxy group (a), and a photoelectric conversion device having a carbon nanotube-containing layer formed from a composition comprising a carbon nanotube (B) About.

A second aspect of the present invention is a working electrode having an oxide semiconductor porous membrane layer carrying a dye supported on at least a part of a conductive layer formed on a substrate, and disposed opposite to the working electrode. A photoelectric conversion element comprising a counter electrode having a conductive layer formed on a substrate, and an electrolyte layer between the working electrode and the counter electrode, the photoelectric conversion element being selected from the working electrode, the counter electrode, and the electrolyte layer Further, a carbon nanotube-containing composition containing a water-soluble conductive polymer (A) having a sulfonic acid group and / or a carboxy group, a carbon nanotube (B) , and a solvent (C) is applied on at least one surface. This is a method for producing a photoelectric conversion element for forming a carbon nanotube-containing layer.

  The photoelectric conversion element of the present invention generates electricity with high efficiency and is excellent in long-term stability. Moreover, according to the manufacturing method of the photoelectric conversion element of this invention, it can manufacture with a coating process and can manufacture at low cost.

Hereinafter, the present invention will be described in detail.
<Photoelectric conversion element (dye-sensitized solar cell)>
The photoelectric conversion element of the present invention is disposed so as to face a working electrode having an oxide semiconductor porous film layer carrying a dye on at least a part of a conductive layer formed on a substrate, and the working electrode. And a counter electrode having a conductive layer formed on a substrate, and an electrolyte layer between the working electrode and the counter electrode.

The conductive layer of the counter electrode is formed from a carbon nanotube-containing composition containing a water-soluble conductive polymer (A), a carbon nanotube (B), and a solvent (C) in order to give conductivity to the surface of the substrate. The carbon nanotube-containing layer can be used. This layer can also be provided via a transparent conductive film formed of ITO, fluorine-doped tin oxide (FTO), tin oxide [SnO ₂ ], or the like.

  Since the carbon nanotube-containing layer can be formed by a coating process using the carbon nanotube-containing composition, the film formation is easy and the manufacturing cost is low. The conductive layer may be a carbon nanotube-containing layer and a metal oxide laminated. As the metal oxide, ITO or FTO is preferable, and a single layer film made of only ITO or a FTO film laminated on an ITO film. A laminated film may be used. If such a transparent conductive film is used, a transparent conductive film with a small amount of light absorption in the visible region and a high conductivity can be formed.

  On the other hand, a light-transmitting substrate is used for the working electrode, and a porous semiconductor film carrying a sensitizing dye is provided through a transparent conductive film (layer) for providing conductivity. As the transparent conductive film (layer), the carbon nanotube-containing layer can be used. Since this layer can be formed by a coating process, film formation is easy and the manufacturing cost is low.

  As the transparent base material used for the working electrode, a substrate made of a light-transmitting material is used, and glass, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyethersulfone, etc. are usually transparent base materials for solar cells. Anything can be used as long as it is used as A transparent base material is appropriately selected from these in consideration of resistance to an electrolytic solution. Moreover, the board | substrate which is excellent in the light transmittance as much as possible for a use is preferable, and the board | substrate whose transmittance | permeability is 90% or more is more preferable.

  As a base material used for the counter electrode, in addition to the base material used for the working electrode, a metal substrate such as titanium can also be used.

The working electrode is formed of oxide semiconductor fine particles such as titanium oxide on the transparent conductive film of the substrate, and forms an oxide semiconductor porous film carrying a photosensitizing dye. The oxide semiconductor porous film may be one or _{two of} titanium oxide (TiO ₂ ), tin oxide (SnO ₂ ), tungsten oxide (WO ₃ ), zinc oxide (ZnO), niobium oxide (Nb ₂ O ₅ ), and the like. It is a porous thin film mainly composed of oxide semiconductor fine particles having an average particle diameter of 1 to 1000 nm and having a thickness of about 0.5 to 50 μm.

  As a method for forming the oxide semiconductor porous film, for example, a dispersion in which commercially available oxide semiconductor fine particles are dispersed in a desired dispersion medium, or a colloidal solution that can be adjusted by a sol-gel method is used as necessary. After adding the desired additives, it is applied by known methods such as screen printing, ink jet printing, roll coating, doctor blade, spin coating, spray coating, etc., and the electrode substrate is immersed in a colloidal solution. Electrophoretic electrodeposition method in which oxide semiconductor fine particles are adhered to the electrode substrate by electrophoresis, a method in which a foaming agent is mixed and applied to a colloidal solution or dispersion, and then sintered and made porous. After mixing and coating, this polymer microbead is removed by heat treatment or chemical treatment to form voids and make it porous. It can be applied.

  The sensitizing dye supported on the oxide semiconductor porous film is not particularly limited. For example, a ruthenium complex or iron complex having a ligand containing a bipyridine structure, a terpyridine structure, or the like, a porphyrin series, or a phthalocyanine series. In addition to these metal complexes, organic dyes such as eosin, rhodamine, merocyanine, and coumarin can be appropriately selected and used according to the application and the material of the oxide semiconductor porous film.

  As the electrolyte layer sealed between the counter electrode and the working electrode, a known electrolyte layer can be used. For example, a porous oxide semiconductor layer impregnated with an electrolytic solution, or an oxide semiconductor porous film After impregnating the electrolytic solution, the electrolytic solution is gelled (pseudo-solidified) using an appropriate gelling agent and formed integrally with the porous oxide semiconductor layer, or the oxidation of the ionic liquid Examples thereof include a gel electrolyte containing physical semiconductor particles and conductive particles. As said electrolyte solution, what melt | dissolved electrolyte components, such as an iodine, iodide ion, and tertiary butyl pyridine, in organic solvents, such as ethylene carbonate and methoxyacetonitrile, is used. Examples of the gelling agent used for gelling the electrolytic solution include polyvinylidene fluoride, a polyethylene oxide derivative, and an amino acid derivative.

Further, the ionic liquid is not particularly limited, and examples thereof include room temperature meltable salts which are liquid at room temperature and have a quaternized nitrogen atom-containing compound as a cation or an anion. Examples of the cation of the room temperature molten salt include quaternized imidazolium derivatives, quaternized pyridinium derivatives, and quaternized ammonium derivatives. Examples of the anion of the room temperature molten salt include BF ⁴⁻ , PF ⁶⁻ , F (HF) ⁿ⁻ , bistrifluoromethylsulfonylimide [N (CF ₃ SO ₂ ) ²⁻ ], iodide ion, and the like. Specific examples of the ionic liquid include salts comprising a quaternized imidazolium meter cation and iodide ion or bistrifluoromethylsulfonylimide ion.

[Water-soluble conductive polymer (A)]
The water-soluble conductive polymer (A) is a conductive polymer having an acidic group composed of a sulfonic acid group and / or a carboxy group. Since the water-soluble conductive polymer (A) improves the solubility / dispersibility of the carbon nanotube (B) and a stable carbon nanotube-containing composition is obtained, as a result, from the composition containing the carbon nanotube. It plays a role of further improving the physical properties such as strength and hardness of the formed layer, conductivity, and the like.

  As the water-soluble conductive polymer (A), a π-conjugated polymer containing phenylene vinylene, vinylene, thienylene, pyrrolylene, phenylene, iminophenylene, isothianaphthene, furylene, carbazolylene or the like as a repeating unit can be used. Among these, a conductive polymer having a skeleton containing thienylene, pyrrolylene, iminophenylene, phenylene vinylene, carbazolylene, and isothianaphthene is particularly preferable.

  The water-soluble conductive polymer (A) can be used as a π-conjugated water-soluble conductive polymer having an acidic group or a salt thereof from the viewpoints of solubility, conductivity, film formability, etc., and is used as the former. It is preferable. Here, as the water-soluble conductive polymer (A), an acid group, an alkyl group substituted with an acidic group, or an acidic group is substituted on the skeleton of a π-conjugated polymer or a nitrogen atom in the polymer. And conductive polymers having an alkyl group containing an ether bond.

Moreover, as a salt of the said water-soluble conductive polymer (A), a water-soluble conductive polymer (A), ammonium salt, and / or amine are made to react, and an acidic group is made into ammonium salt (-SO4) of a sulfonic acid group. ₃ ^- M ^<+> ) and / or an ammonium salt of a carboxy group (-COO ^- M ^<+> ) can be used. Here, the ammonium ion (M ⁺ ) of the ammonium salt is represented by the following general formula (1).

(In the formula (1), R ^{1 to} R ⁴ are each independently hydrogen, alkyl having 1 to 24 carbon atoms, aryl or aralkyl group, phenyl group, benzyl group, R ⁵ OH, CONH ₂ or NH ₂ ; ^At least one of ^{1 to} R ⁴ is a group having 5 or more carbon atoms, wherein R ⁵ is an alkylene, arylene or aralkylene group having 1 to 24 carbon atoms.

  Examples of the water-soluble conductive polymer (A) include JP-A 61-197633, JP-A 63-39916, JP-A 01-301714, JP-A 05-504153, and JP-A 05-. No. 503953, JP 04-32848, JP 04-328181, JP 06-145386, JP 06-56987, JP 05-226238, JP 05-17889. JP, JP 06-293828, JP 07-118524, JP 06-32845, JP 06-87949, JP 06-256516, JP 07-41756, JP 07-48436 A, JP 04-268331 A, JP 09-59376 A, 2000-172384, JP-A No. 06-49183, JP-was disclosed in JP-A-10-60108 water-soluble electroconductive polymer is preferably used.

  Further, as a preferable water-soluble conductive polymer (A), at least one or more repeating units selected from the following general formulas (2) to (10) are contained in an amount of 20 to 100% in the total number of repeating units of the whole polymer. A conductive polymer.

(In the formula ^{(2), R 6, R} 7 each _{^{independently, H, -SO 3 -, -SO}} 3 - M +, -SO 3 H
_{^{, -R 8 SO 3 -, -R}} 8 SO 3 - M +, -R 8 SO 3 H, -OCH 3, -CH 3, -C 2 H 5, -F, -Cl, -Br, -I, _{^{-N (R 8) 2, -NHCOR}} 8, -OH, -O -, -SR 8, -OR 8, -OCOR 8, -NO 2, -COO - M +, -COOH, -R 8 COOH, - R ⁸ COO ^— M ⁺ , —COOR ⁸ , —COR ⁸ , —CHO and —CN, wherein M ⁺ is an ammonium ion represented by the formula (1), and R ⁸ is An alkyl, aryl or aralkyl group having 1 to 24 carbon atoms, or an alkylene, arylene or aralkylene group, and at least one of R ⁶ and R ⁷ is —SO ₃ ^— , —SO ₃ H, —R ⁸ SO ₃ ^— , -R ⁸ SO ₃ H, -COO , + ^-R 8 COOH, and _{^{-SO 3 M, -R 8 SO 3}} - M +, -COO - M +, -R 8 COO - is a group selected from the group consisting of ^{M +.} )

(In the formula ^{(3), R 9, R} 10 are each _{^{independently, H, -SO 3 -, -SO}} 3 - M +, -SO 3 H, -R 11 SO 3 -, -R 11 SO 3 - M _{^{+, -R 11 SO 3 H,}} -OCH 3, -CH 3, -C 2 H 5, -F, -Cl, -Br, -I, -N (R 11) 2, -NHCOR 11, -OH, ^{-O -, -SR 11, -OR 11} , -OCOR 11, -NO 2, -COO - M +, -COOH, -R 11 COOH, -R 11 COO - M +, -COOR 11, -COR 11, Selected from the group consisting of —CHO and —CN, wherein M ⁺ is an ammonium ion represented by the formula (1), and R ¹¹ is an alkyl, aryl or aralkyl group or alkylene having 1 to 24 carbon atoms, An arylene or aralkylene group And ^{R 9,} at least one of ^{R 10} is _{^{-SO 3 -, -SO 3 H,}} -R 11 SO 3 -, -R 11 SO 3 H, -COOH, -R 11 COOH, and _-SO ³ - ^{M + _{, -R 11 SO 3 - M +}} , -COO - M +, -R 11 COO - is a group selected from the group consisting of ^{M +).}

(In the formula ^{(4), R} 12 ~R ¹⁵ are each independently _{^{H, -SO 3 -, -SO 3}} - M +, -SO 3 H, -R 16 SO 3 -, -R 16 SO 3 - M + _{^{, -R 16 SO 3 H, -OCH}} 3, -CH 3, -C 2 H 5, -F, -Cl, -Br, -I, -N (R 16) 2, -NHCOR 16, -OH, - ^{O -, -SR 16, -OR 16} , -OCOR 16, -NO 2, -COO - M +, -COOH, -R 16 COOH, -R 16 COO - M +, -COOR 16, -COR 16, - Selected from the group consisting of CHO and —CN, wherein M ⁺ is an ammonium ion represented by the formula (1), and R ¹⁶ is an alkyl, aryl or aralkyl group or alkylene or arylene having 1 to 24 carbon atoms. Or an aralkylene group And at least one of _-SO ³ of _{^{R 12 ~R 15 -, -SO 3}} H, -R 16 SO 3 -, -R 16 SO 3 H, -COOH, -R 16 COOH, and _-SO ³ - ^{M + _{, -R 16 SO 3 - + M}} , -COO - M +, -R 16 COO - as ^{M +} group selected from the group consisting of).

(In the formula ^{(5), R} 17 ~R ²¹ are each _{^{independently, H, -SO 3 -, -SO}} 3 - M +, -SO 3 H, -R 22 SO 3 -, -R 22 SO 3 - M _{^{+, -R 22 SO 3 H,}} -OCH 3, -CH 3, -C 2 H 5, -F, -Cl, -Br, -I, -N (R 22) 2, -NHCOR 22, -OH, ^{-O -, -SR 22, -OR 22} , -OCOR 22, -NO 2, -COO - M +, -COOH, -R 22 COOH, -R 22 COO - M +, -COOR 22, -COR 22, Selected from the group consisting of —CHO and —CN, wherein M ⁺ is an ammonium ion represented by the above formula (1), R ²² is an alkyl, aryl or aralkyl group or alkylene having 1 to 24 carbon atoms, An arylene or aralkylene group And at least one of _-SO ³ of _{^{R 17 ~R 21 -, -SO 3}} H, -R 22 SO 3 -, -R 22 SO 3 H, -COOH, -R 22 COOH, and -SO ₃ ^- M _{^{+, -R 22 SO 3 - M}} +, -COO - M +, -R 22 COO - is a group selected from the group consisting of ^{M +).}

(In the formula ^{(6), R} 23 _{^{is, -SO 3 -, -SO 3 H}} , -R 24 SO 3 -, -R 24 SO 3 H, -COOH, -R 24 COOH, and _-SO ³ - ^{M + _{, -R 25 SO 3 - + M}} , -COO - M + and ^-R 25 ^COO - selected from the group consisting of ^{M +,} wherein, ^{M +} is an ammonium ion represented by the formula (1), R ²⁴ is an alkyl, aryl or aralkyl group having 1 to ²⁴ carbon atoms or an alkylene, arylene or aralkylene group, and R ²⁵ is an alkylene, arylene or aralkylene group having 1 to 24 carbon atoms.

(In the formula (7), R ^{26 to} R ³¹ are each independently H, —SO ₃ ^— , —SO ₃ ^— M ⁺ , —SO ₃ H, —R ³² SO ₃ ^— , —R ³² SO ₃ ^— M. _{^{+, -R 32 SO 3 H,}} -OCH 3, -CH 3, -C 2 H 5, -F, -Cl, -Br, -I, -N (R 32) 2, -NHCOR 32, -OH, ^{-O -, -SR 32, -OR 32} , -OCOR 32, -NO 2, -COO - M +, -COOH, -R 32 COOH, -R 32 COO - M +, -COOR 32, -COR 32, Selected from the group consisting of —CHO and —CN, wherein M ⁺ is an ammonium ion represented by the formula (1), and R ³² is an alkyl, aryl or aralkyl group or alkylene having 1 to 24 carbon atoms, An arylene or aralkylene group And at least one of _-SO of _{^{R 26 ~R 31 3 -, -SO}} 3 H, -R 5 SO 3 -, -R 32 SO 3 H, -COOH, -R 32 COOH, and -SO ₃ ^- M _{^{+, -R 32 SO 3 - +}} M, -COO - M +, -R 32 COO - a ^{M +} group selected from the group consisting of, Ht ^consists NR 33, S, O, Se and Te A heteroatom group selected from the group, wherein R ³³ represents hydrogen and a linear or branched alkyl group having 1 to 24 carbon atoms or a substituted or unsubstituted aryl group, and a hydrocarbon chain of R ^{26 to} R ³¹ Are bonded to each other at any position to form a divalent chain that forms a cyclic structure of at least one or more 3- to 7-membered saturated or unsaturated hydrocarbons with carbon atoms substituted by such groups. May be formed like this Carbonyl annularly connecting chain, ether, ester, amide, sulfide, sulfinyl, sulfonyl, may include imino at an arbitrary position, n _a is sandwiched benzene ring having a substituent group R ²⁷ to R ³⁰ and heterocycle Represents the number of condensed rings formed, and is an integer of 0 or 1 to 3.)

(In the formula ^(8), the R 34 ^{to R 42} are each _{^{independently, H, -SO 3 -, -SO}} 3 - M +, -SO 3 H, -R 43 SO 3 -, -R 43 SO 3 - M _{^{+, -R 43 SO 3 H,}} -OCH 3, -CH 3, -C 2 H 5, -F, -Cl, -Br, -I, -N (R 43) 2, -NHCOR 43, -OH, ^{-O -, -SR 43, -OR 43} , -OCOR 43, -NO 2, -COO - M +, -COOH, -R 43 COOH, -R 43 COO - M +, -COOR 43, -COR 43, Selected from the group consisting of —CHO and —CN, wherein M ⁺ is an ammonium ion represented by the formula (1), and R ⁴³ is an alkyl, aryl or aralkyl group or alkylene having 1 to 24 carbon atoms, An arylene or aralkylene group And at least one of _-SO of _{^{R 34 ~R 42 3 -, -SO}} 3 H, -R 43 SO 3 -, -R 43 SO 3 H, -COOH, -R 43 COOH, and -SO ₃ ^- M _{^{+, -R 43 SO 3 - M}} +, -COO - M +, -R 43 COO - a group selected from the group consisting of ^{M +,} _{n b} is a benzene ring having a substituent ^{R 34} and ^{R 35} This represents the number of condensed rings sandwiched between benzene rings having substituents R ^{37 to} R ⁴⁰ , and is an integer of 0 or 1-3.

(In the formula (9), R ^{44 to} R ⁵³ are each independently H, —SO ₃ ^— , —SO ₃ ^— M ⁺ , —SO ₃ H, —R ⁵⁴ SO ₃ ^— , —R ⁵⁴ SO ₃ ^— M. _{^{+, -R 54 SO 3 H,}} -OCH 3, -CH 3, -C 2 H 5, -F, -Cl, -Br, -I, -N (R 54) 2, -NHCOR 54, -OH, ^{-O -, -SR 54, -OR 54} , -OCOR 54, -NO 2, -COO - M +, -COOH, -R 54 COOH, -R 54 COO - M +, -COOR 54, -COR 54, Selected from the group consisting of —CHO and —CN, wherein M ⁺ is an ammonium ion represented by the formula (1), R ⁵⁴ is an alkyl, aryl or aralkyl group or alkylene having 1 to 24 carbon atoms, An arylene or aralkylene group And at least one of _-SO of _{^{R 44 ~R 53 3 -, -SO}} 3 H, -R 54 SO 3 -, -R 54 SO 3 H, -COOH, -R 54 COOH, and -SO ₃ ^- M _{^{+, -R 54 SO 3 - M}} +, -COO - M +, -R 54 COO - a group selected from the group consisting of ^{M +,} _{n c} is a benzene ring having a substituent ^R 44 ^{to R 46} This represents the number of condensed rings sandwiched between benzoquinone rings and is an integer of 0 or 1-3.)

(In the formula ^(10), each independently R 55 ^{to R 59 _{is, H, -SO 3 -, -SO}} 3 - M +, -SO 3 H, -R 60 SO 3 -, -R 60 SO 3 - M _{^{+, -R 60 SO 3 H,}} -OCH 3, -CH 3, -C 2 H 5, -F, -Cl, -Br, -I, -N (R 60) 2, -NHCOR 60, -OH, ^{-O -, -SR 60, -OR 60} , -OCOR 60, -NO 2, -COO - M +, -COOH, -R 60 COOH, -R 60 COO - M +, -COOR 60, -COR 60, Selected from the group consisting of —CHO and —CN, wherein M ⁺ is an ammonium ion represented by the above formula (1), R ⁶⁰ is an alkyl, aryl or aralkyl group or alkylene having 1 to 24 carbon atoms, An arylene or aralkylene group Ri, and at least one of _-SO ³ of _{^{R 55 ~R 59 -, -SO 3}} H, -R 60 SO 3 -, -R 60 SO 3 H, -COOH, -R 60 COOH, and -SO ₃ ^{- _{M +, -R 60 SO 3 -}} M +, -COO - M +, -R 60 COO - is a group selected from the group consisting of ^{M +, X a-} is chloride, bromide, iodide, Fluorine ion, nitrate ion, sulfate ion, hydrogen sulfate ion, phosphate ion, borofluoride ion, perchlorate ion, thiocyanate ion, acetate ion, propionate ion, methanesulfonate ion, p-toluenesulfonate ion, A is an at least one anion selected from the group of 1 to 3 anions composed of trifluoroacetate ions and trifluoromethanesulfonate ions, Of represents an ion valence, an integer of 1 to 3, p is doping ratio, its value is 0.001.)

  Another preferred water-soluble conductive polymer (A) is polyethylene dioxythiophene polystyrene sulfate. This water-soluble conductive polymer has a structure in which polystyrene sulfonic acid is added as a dopant, although no sulfonic acid group is introduced into the skeleton of the conductive polymer. Moreover, as the water-soluble conductive polymer (A) having an ammonium salt of an acidic group (a), polyethylenedioxythiophene polystyrene sulfonate ammonium or substituted ammonium salt can also be used. This water-soluble conductive polymer has a structure in which ammonium sulfonate is not introduced into the skeleton of the conductive polymer, but polystyrene sulfonate ammonium salt is added as a dopant.

As specific examples of these water-soluble conductive polymers (A), 3,4-ethylenedioxythiophene (Baytron M manufactured by Bayer) is polymerized with an oxidizing agent such as iron toluenesulfonate (Baytron C manufactured by Bayer). And an adduct of polyethylenedioxythiophene and polystyrene sulfonic acid produced by the above, or a product obtained by reacting this adduct with amines or ammonia. Moreover, what was obtained by reacting Baytron P (manufactured by Bayer) or Baytron P with amines and / or ammoniums can be used.

  Among these other preferable water-soluble conductive polymers (A), those containing 20 to 100% of the repeating unit represented by the following general formula (11) in the total number of repeating units of the whole polymer are more preferable. preferable.

(In formula (11), y represents an arbitrary number of 0 <y <1, and R ^{61 to} R ⁷⁸ are each independently H, —SO ₃ ⁻ , —SO ₃ ⁻ M ⁺ , —SO ₃ H, _{^{-R 79 SO 3 -, -R 79}} SO 3 - M +, -R 79 SO 3 H, -OCH 3, -CH 3, -C 2 H 5, -F, -Cl, -Br, -I, - _{^{N (R 79) 2, -NHCOR}} 79, -OH, -O -, -SR 79, -OR 79, -OCOR 79, -NO 2, -COO - M +, -COOH, -R 79 COOH, -R ⁷⁹ COO ⁻ M ⁺ , —COOR ⁷⁹ , —COR ⁷⁹ , —CHO and —CN, wherein M ⁺ is an ammonium ion represented by the formula (1), and R ⁷⁹ is carbon. An alkyl, aryl or aralkyl group of 1 to 24 or alkylene Arylene or aralkylene ^group, at least one of _-SO of _{^{R 61 ~R 78 3 -, -SO}} 3 H, -R 79 SO 3 -, -R 79 SO 3 H, -COOH, -R 79 COOH, and _{^{-SO 3 - M +, -R 79}} SO 3 - M +, -COO - M +, -R 79 COO - is a group selected from the group consisting of ^{M +).}

  Among the water-soluble conductive polymers (A), a repeating group having an acidic group (a) with respect to the total number of repeating units of the polymer, because the solubility in a solvent such as an organic solvent or a water-containing organic solvent is very good. The unit content is preferably 50% or more. The content of the repeating unit having an acidic group (a) is more preferably 70% or more, further preferably 90% or more, and particularly preferably 100%.

  The substituent added to the aromatic ring is preferably an alkyl group, an alkoxy group, or a halogen group from the viewpoint of conductivity and solubility, and particularly preferably an alkoxy group having an electron donating property. Among these combinations, the most preferable water-soluble conductive polymer (A) is represented by the following general formula (12).

(In the formula ^{(12), R} 80 ~R ⁸³ is a sulfonic acid group, a carboxy group, and alkali metal salts thereof, is one group selected from the group consisting of ammonium salts and substituted ammonium ^{salts, R 80} ~ At least one of R ⁸³ is a group selected from the group consisting of a sulfonic acid group, a carboxy group, and ammonium salts thereof, and R ⁸⁴ is a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, n-butyl, iso-butyl, sec-butyl, tert-butyl, dodecyl, tetracosyl, methoxy, ethoxy, n-propoxy, iso-butoxy, sec-butoxy, tert-butoxy Group, heptoxy group, hexoxy group, octoxy group, dodecoxy group, tetracosoxy group, fluoro group, chloro group and bromo group 1 represents a group selected from the group consisting of: x represents an arbitrary number of 0 <x <1, m represents a degree of polymerization and is 3 or more.) R ^{80 to} R ⁸³ are, among others, conductive In view of high properties, sulfonic acid groups and alkali metal salts, ammonium salts and substituted ammonium salts of sulfonic acid groups are preferred.

  The water-soluble conductive polymer (A) in the present invention can be obtained by various synthetic methods such as chemical polymerization or electrolytic polymerization. For example, the synthesis methods described in JP-A-7-196791 and JP-A-7-324132 proposed by the present inventors can be applied. That is, one compound selected from the group consisting of an acidic group-substituted aniline represented by the following general formula (13), an alkali metal salt thereof, an ammonium salt, and a substituted ammonium salt is oxidized with an oxidizing agent in a solution containing a basic compound. A water-soluble conductive polymer (A) can be obtained by polymerization.

(In the formula ^{(13), R} 85 ~R ⁹⁰ are each _{^{independently, H, -SO 3 -, -SO}} 3 - M +, -SO 3 H, -R 91 SO 3 -, -R 91 SO 3 - M _{^{+, -R 91 SO 3 H,}} -OCH 3, -CH 3, -C 2 H 5, -F, -Cl, -Br, -I, -N (R 91) 2, -NHCOR 91, -OH, ^{-O -, -SR 91, -OR 91} , -OCOR 91, -COO - M +, -COOH, -R 91 COOH, -R 91 COO - M +, -COOR 91, -COR 91, -CHO and - Selected from the group consisting of CN, wherein M ⁺ is an ammonium ion represented by the formula (1), and R ⁹¹ is an alkyl, aryl or aralkyl group or alkylene, arylene or aralkylene group having 1 to 24 carbon atoms. And R ⁸⁵ At least one of _-SO ³ of _{^{~R 90 -, -SO 3 H,}} -R 91 SO 3 -, -R 91 SO 3 H, -COOH, -R 91 COOH, and _-SO ³ - ^M +, -R ⁹¹ SO ₃ ⁻ M ⁺ , —COO ⁻ M ⁺ , and —R ⁹¹ COO ⁻ M ⁺ .

  A particularly preferred water-soluble conductive polymer (A) can be obtained by polymerizing an alkoxy group-substituted aminobenzenesulfonic acid, its alkali metal salt, ammonium salt, or substituted ammonium salt with an oxidizing agent in a solution containing a basic compound. It is a water-soluble conductive polymer.

  A simple method for synthesizing a water-soluble conductive polymer having an ammonium salt of a sulfonic acid group and / or an ammonium salt of a carboxy group from the water-soluble conductive polymer (A) is represented by the following general formula (14). And a method in which an amine represented by the following general formula (15) and the water-soluble conductive polymer (A) are reacted in a solution.

(In the formula (14), R ^{101 to} R ¹⁰⁴ are each independently hydrogen, R ¹⁰⁵ OH, alkyl having 1 to 24 carbon atoms, aryl or aralkyl group, phenyl group, benzyl group, CONH ₂ or NH ₂ , and At least one of R ^{101 to} R ¹⁰⁴ is a group having 5 or more carbon atoms, R ¹⁰⁵ is an alkylene, arylene or aralkylene group having 1 to 24 carbon atoms, and Y ^b− is a hydroxide ion, a chlorine ion, or a bromine. Ion, iodine ion, fluorine ion, nitrate ion, sulfate ion, hydrogen sulfate ion, amidosulfuric acid ion, sulfite ion, phosphinate ion, phosphate ion, pyrophosphate ion, tripolyphosphate ion, borofluoride ion, perchlorate ion , Thiocyanate ion, acetate ion, propionate ion, methanesulfonate ion, p-tolu Sulfonate ion, valerate ion, dodecylbenzene sulfonate ion, camphor sulfonate ion, butyrate ion, formate ion, trimethyl acetate ion, bromoacetate ion, lactate ion, citrate ion, succinate ion, oxalate ion, tartaric acid ion , Fumarate ion, maleate ion, malonate ion, ascorbate ion, anisate ion, anthranilate ion, benzoate ion, cinnamic acid ion, phenylacetate ion, phthalate ion, aniline sulfonate ion, thiocarboxylate ion And at least one anion selected from the group of 1 to 3 anions consisting of methylsulfinate ion, trifluoroacetate ion, and trifluoromethanesulfonate ion, and b is the ionic valence of Y. Yes, an integer from 1 to 3 Shown, j is an integer of 1-3.)

(In the formula (15), R ^{106 to} R ¹⁰⁸ are each independently hydrogen, alkyl having 1 to 24 carbon atoms, aryl or aralkyl group, phenyl group, benzyl group, R ¹⁰⁵ OH, CONH ₂ or NH ₂ ; And at least one of R ^{106 to} R ¹⁰⁸ is a group having 5 or more carbon atoms, wherein R ¹⁰⁵ is an alkylene, arylene or aralkylene group having 1 to 24 carbon atoms.

  Examples of ammonium salts include alkyldimethylbenzylammonium halides such as benzalkonium chloride and trimethylbenzylammonium chloride, alkyldiethylbenzylammonium halides such as alkyldiethylbenzylammonium chloride and triethylbenzylammonium bromide, and trioctylmethylammonium chloride. Preferred are tetraalkylammonium halides and trimethylbenzylammonium hydroxide.

  Examples of amines include benzylamine, tri-n-octylamine, di-n-octylamine, 2-ethylhexylamine, 3- (2-ethylhexyloxy) propylamine, aniline, dimethylaniline, diethylaniline, di- Anilines such as n-propylaniline and di-iso-propylaniline are preferred.

  The water-soluble conductive polymer (A) has a mass average molecular weight of preferably 2,000 to 3,000,000, preferably 3,000 to 1,000, in terms of polyethylene glycol in gel permeation chromatography (GPC). Is more preferably 5,000 to 500,000. When the water-soluble conductive polymer (A) has a mass average molecular weight of 2,000 or more, sufficient film strength, film formability, and conductivity are easily obtained. Moreover, if the water-soluble conductive polymer (A) has a mass average molecular weight of 3,000,000 or less, excellent solubility is easily obtained.

Although the said water-soluble conductive polymer (A) can be used as it is, what carried out the doping process method by the acid of a well-known method, and provided the external dopant may be used. For example, the doping treatment can be performed by a treatment such as immersing the water-soluble conductive polymer (A) in an acidic solution.
Specifically, the acidic solution used for the doping treatment includes inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid; organic acids such as p-toluenesulfonic acid, camphorsulfonic acid, benzoic acid, and derivatives having these skeletons; polystyrene sulfonic acid , Polyvinyl sulfonic acid, poly (2-acrylamido-2-methylpropane) sulfonic acid, polyvinyl sulfuric acid and aqueous solutions containing polymer acids such as derivatives having these skeletons, or water-organic solvent mixed solutions. These inorganic acids, organic acids, and polymer acids may be used alone, or two or more kinds may be mixed and used in an arbitrary ratio.

[Carbon nanotube (B)]
Examples of the carbon nanotube (B) in the present invention include fullerene, metal-encapsulated fullerene, onion-like fullerene, carbon nanotube, carbon nanohorn, carbon nanofiber, peapod, vapor grown carbon (VGCF), graphite, graphene, and carbon nanoparticle. , Ketjen black and the like. Among these, carbon nanotubes are preferred from the viewpoint of conductivity and transparency in practical use.

  The carbon nanotube (B) is not particularly limited, and normal carbon nanotubes can be used. For example, single-walled carbon nanotubes, multi-walled carbon nanotubes in which several layers are concentrically stacked, and these are coiled. A thing etc. can be used.

  Further, the carbon nanotube (B) has a single-layer or multiple-nested cylinder with a graphite-like carbon atom surface in a layer of several atoms in thickness, and has an extremely small outer diameter on the order of nm. Materials. In addition, a carbon nanohorn having a shape in which one side of the carbon nanotube is closed, a cup-shaped nanocarbon material having a hole in the head thereof, or the like can also be used.

  The method for producing the carbon nanotube (B) is not particularly limited. Specifically, catalytic hydrogen reduction of carbon dioxide, arc discharge method, laser evaporation method, CVD method, vapor phase growth method, gas phase flow method, carbon monoxide is reacted with iron catalyst at high temperature and high pressure in the gas phase. Examples include HiPco method for growth.

  The carbon nanotubes (B) are preferably single-walled carbon nanotubes and multi-walled carbon nanotubes obtained by these production methods. From the viewpoint that various functions are more easily expressed, cleaning methods, centrifugal separation methods, and filtration methods are further used. More preferably, the carbon nanotube is more highly purified by various purification methods such as an oxidation method and a chromatographic method.

  As the carbon nanotube (B), the above-mentioned materials are pulverized using a ball-type kneader such as a ball mill, a vibration mill, a sand mill, a roll mill or the like, or cut short by chemical and physical treatments. What has been used can also be used.

[Solvent (C)]
The solvent (C) in the present invention plays a role of further improving dispersibility of the water-soluble conductive polymer (A) and the carbon nanotube (B), and improving coating properties, operability and the like. The solvent (C) is not particularly limited as long as it dissolves or disperses the carbon nanotube (B), but a solvent (C) that dissolves or disperses the water-soluble conductive polymer (A) is preferable.

Examples of the solvent (C) include water, methanol, ethanol, isopropyl alcohol, propyl alcohol, butanol and other alcohols; acetone, methyl ethyl ketone, ethyl isobutyl ketone, methyl isobutyl ketone, diacetone alcohol and the like ketones; ethyl acetate, acetic acid Esters such as n-butyl, isobutyl acetate, n-amyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate; ethylene glycols such as ethylene glycol, ethylene glycol methyl ether, ethylene glycol mono-n-propyl ether; propylene glycol, Propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol butyl ether, propylene glycol propyl ether Propylene glycols such as tellurium and propylene glycol monomethyl ether acetate; amides such as dimethylformamide and dimethylacetamide; pyrrolidones such as N-methylpyrrolidone and N-ethylpyrrolidone; dimethylsulfoxide, γ-butyrolactone, methyl lactate, ethyl lactate , Hydroxy esters such as methyl β-methoxyisobutyrate and methyl α-hydroxyisobutyrate; anilines such as aniline and N-methylaniline, aromatic hydrocarbons such as benzene, toluene and xylene, m-cresol, acetonitrile, tetra Hydrofuran, 1,4-dioxane, ethyl cellosolve, butyl cellosolve, and methoxypropanol are preferred.
Among these, water or a water-containing organic solvent is more preferable from the viewpoint of the solubility of the water-soluble conductive polymer (A) and the dispersibility of the carbon nanotube (B).

[Basic compound (D)]
The carbon nanotube-containing composition in the present invention preferably further contains a basic compound (D) in addition to the water-soluble conductive polymer (A), carbon nanotube (B), and solvent (C) described above. When the basic compound (D) is added to the carbon nanotube-containing composition, the water-soluble conductive polymer (A) as a constituent component is dedoped, and the solubility in the composition is further improved. The solubilization or dispersion of the nanotube (B) in the composition is promoted.

The basic compound (D) is not particularly limited, but ammonia, fatty amines, cyclic saturated amines, cyclic unsaturated amines, ammonium salts, and inorganic bases are preferable.
The structural formula of ammonia and fatty amines is shown in the following general formula (16). The structural formula of ammonium salts is shown in the following general formula (17).

(In the formula ^{(16), R} 201 ~R ²⁰³ is each independently of the other represents hydrogen, an alkyl group having 1 to 4 carbon _{atoms, CH 2 OH, CH 2 CH} 2 OH, a CONH ₂ or NH _2.)

(In the formula ^(17), the R 204 ^{to R 207} are each independently of one another, represent hydrogen, an alkyl group having 1 to 4 carbon _{atoms, CH 2 OH, CH 2 CH} 2 OH, a CONH ₂ or NH _2, Z ^- is OH ⁻ , 1/2 · SO ₄ ²⁻ , NO ₃ ⁻ , 1 / 2CO ₃ ²⁻ , HCO ₃ ⁻ , 1/2 · (COO) ₂ ²⁻ , or R ²⁰⁸ COO ⁻ , R ²⁰⁸ represents carbon (It is a C 1-3 alkyl group.)

As the cyclic saturated amines, piperidine, pyrrolidine, morpholine, piperazine, derivatives having these skeletons, and ammonium hydroxide compounds thereof are preferable.
As the cyclic unsaturated amines, pyridine, α-picoline, β-picoline, γ-picoline, quinoline, isoquinoline, pyrroline, derivatives having these skeletons, and ammonium hydroxide compounds thereof are preferable.
As the inorganic base, hydroxide salts such as sodium hydroxide, potassium hydroxide and lithium hydroxide are preferable.

The basic compound (D) may be used alone or in combination of two or more. For example, the conductivity of the carbon nanotube-containing layer obtained can be further improved by using a mixture of amines and ammonium salts. Specifically, NH ₃ / (NH ₄ ) ₂ CO ₃ , NH ₃ / (NH ₄ ) HCO ₃ , NH ₃ / CH ₃ COONH ₄ , NH ₃ / (NH ₄ ) ₂ SO ₄ , N (CH ₃ ) ₃ / CH ₃ COONH ₄ , N (CH ₃ ) ₃ / (NH ₄ ) ₂ SO _4, etc. may be used in combination. Further, the mixing ratio (mass ratio) of these can be any ratio, but is preferably amines / ammonium salts = 1/10 to 10/1.

[Polymer Compound (E)]
Moreover, it is preferable that the carbon nanotube containing composition in this invention further contains a high molecular compound (E). By including the polymer compound (E), the substrate adhesion and strength of the water-resistant conductor can be further improved.
The polymer compound (E) is not particularly limited as long as it can be dissolved or dispersed in the carbon nanotube-containing composition in the present invention. For example, polyvinyl alcohols such as polyvinyl alcohol, polyvinyl formal, and polyvinyl butyral; polyacrylamide , Polyacrylamides such as poly (Nt-butyl acrylamide), polyacrylamide methylpropane sulfonic acid; polyvinylpyrrolidones, polystyrene sulfonic acid and its soda salts, cellulose, alkyd resin, melamine resin, urea resin, phenol Resin, epoxy resin, polybutadiene resin, acrylic resin, urethane resin, vinyl ester resin, urea resin, polyimide resin, maleic acid resin, polycarbonate resin, vinyl acetate resin, chlorinated polyethylene Resins, chlorinated polypropylene resins, styrene resins, acryl / styrene copolymer resin, a vinyl acetate / acrylic copolymer resin, polyester resin, styrene / maleic acid copolymer resins, fluorine resins and copolymers thereof and the like can be used.
These high molecular compounds (E) may be used individually by 1 type, and may use 2 or more types together.

  Among these polymer compounds (E), when a conductive polymer having an ammonium salt of a sulfonic acid group and / or an ammonium salt of a carboxy group is used as the water-soluble conductive polymer (A), solubility in a solvent, composition Alkyd resin, melamine resin, urea resin, phenol resin, epoxy resin, polybutadiene resin, acrylic resin, urethane resin, vinyl ester resin, urea resin, polyimide resin, maleic acid resin, polycarbonate Resin, vinyl acetate resin, styrene resin, acrylic / styrene copolymer resin, vinyl acetate / acrylic copolymer resin, polyester resin, styrene / maleic acid copolymer resin are preferable, phenol resin, epoxy resin, polybutadiene resin, acrylic resin, urethane Resin, acrylic / steel Copolymer resin, vinyl acetate / acrylic copolymer resin, it is particularly preferred to use a mixture of one or more of the polyester resin.

  In the case of using the water-soluble conductive polymer (A) having an acidic group (a) that does not form an ammonium salt, the solubility of the water-soluble polymer compound or the polymer compound that forms an emulsion in an aqueous system in a solvent. In view of the stability and conductivity of the composition, a polymer compound having an anion group is preferable, and water-based fluorine such as water-based acrylic resin, water-based polyester resin, water-based urethane resin, water-based chlorinated polyolefin resin, and tetrafluoroethylene resin. It is more preferable to use a mixture of one or more of the resins.

[Surfactant (F)]
The carbon nanotube-containing composition in the present invention may further contain a surfactant (F). By containing the surfactant (F), the solubilization or dispersion of the carbon nanotube (B) is further promoted, and the flatness, coating property, conductivity and the like of the carbon nanotube-containing layer are improved.

  Examples of the surfactant (F) include alkylsulfonic acid, alkylbenzenesulfonic acid, alkylcarboxylic acid, alkylnaphthalenesulfonic acid, α-olefinsulfonic acid, dialkylsulfosuccinic acid, α-sulfonated fatty acid, and N-methyl-N. -Oleyl taurine, petroleum sulfonic acid, alkyl sulfuric acid, sulfated oil, polyoxyethylene alkyl ether sulfuric acid, polyoxyethylene styrenated phenyl ether sulfuric acid, alkyl phosphoric acid, polyoxyethylene alkyl ether phosphoric acid, polyoxyethylene alkyl phenyl ether phosphorus Anionic surfactants such as acids, naphthalenesulfonic acid formaldehyde condensates and their salts; primary to tertiary fatty amines, quaternary ammonium, tetraalkylammonium, trialkylbenzylammonium Rualkylpyridinium, 2-alkyl-1-alkyl-1-hydroxyethylimidazolinium, N, N-dialkylmorpholinium, polyethylene polyamine fatty acid amide, urea condensate of polyethylene polyamine fatty acid amide, urea condensate of polyethylene polyamine fatty acid amide Cationic surfactants such as quaternary ammonium and salts thereof; N, N-dimethyl-N-alkyl-N-carboxymethylammonium betaine, N, N, N-trialkyl-N-sulfoalkylene ammonium betaine, Betaines such as N, N-dialkyl-N, N-bispolyoxyethyleneammonium sulfate betaine, 2-alkyl-1-carboxymethyl-1-hydroxyethylimidazolinium betaine, N, N-dialkylaminoalkylene Amphoteric surfactants such as aminocarboxylic acids such as rubonic acid salts; polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene polystyryl phenyl ether, polyoxyethylene-polyoxypropylene glycol, polyoxyethylene-poly Oxypropylene alkyl ether, polyhydric alcohol fatty acid partial ester, polyoxyethylene polyhydric alcohol fatty acid partial ester, polyoxyethylene fatty acid ester, polyglycerin fatty acid ester, polyoxyethylenated castor oil, fatty acid diethanolamide, polyoxyethylene alkylamine, Non-ionic surfactants such as triethanolamine fatty acid partial esters and trialkylamine oxides; and fluoroalkyl carboxylic acids, perfur B alkyl carboxylic acids, perfluoro benzene sulfonic acid, fluorine-based surfactants such as perfluoroalkyl polyoxyethylene ethanol. Here, the alkyl group preferably has 1 to 24 carbon atoms, and more preferably 3 to 18 carbon atoms. These surfactants (F) may be used alone or in combination of two or more.

[Particulate matter (G)]
Further, the carbon nanotube-containing composition of the present invention may further contain a particulate material (G). By including the particulate material (G), the conductivity of the carbon nanotube-containing layer can be further improved.
The particulate material (G) is not particularly limited as long as it is a particulate material having conductivity, and examples thereof include organic particles, inorganic particles, ceramic particles, metal oxide particles, metal particles, dyes, and pigments. Is mentioned.

  Specifically, acrylic resin particles, silica, colloidal silica, plate-like alumina, fibrous alumina, zirconia, spinel, talc, mullite, cordierite, silicon carbide, aluminum oxide, titanium oxide, yttrium oxide, cerium oxide, Samarium oxide, lanthanum oxide, terbium oxide, europium oxide, neodymium oxide, zinc oxide, titanium oxide, tin oxide, copper oxide, holmium oxide, bismuth oxide, cobalt oxide, gnesium fluoride, tin oxide, indium oxide, tin oxide containing antimony (ATO), tin-containing indium oxide (ITO), zinc antimonate, antimony pentoxide, gold, silver, copper, nickel and other metal particles, hematite, cobalt blue, cobalt violet, cobalt green, magnetite, Mn-Zn ferrite Ni-Zn ferrite, barium titanate, and magnesium hydroxide.

Among these granular substances (G), yttrium oxide, cerium oxide, samarium oxide, lanthanum oxide, terbium oxide, europium oxide, neodymium oxide, zinc oxide, titanium oxide, magnesium fluoride, tin oxide are more excellent in conductivity. Metal particles such as indium oxide, antimony-containing tin oxide (ATO), tin-containing indium oxide (ITO), zinc antimoate, antimony pentoxide, gold, silver, copper, and nickel are preferable.
In addition, zinc oxide, tin oxide, indium oxide, antimony-containing tin oxide (ATO), tin-containing indium oxide (ITO), zinc antimonate, antimony pentoxide, gold, silver are excellent in dispersibility in the solvent (C). Metal particles such as copper and nickel are preferred.

In addition, the carbon nanotube-containing composition in the present invention may further include a plasticizer, a dispersant, a coating surface modifier, a fluidity modifier, an ultraviolet absorber, a storage stabilizer, an adhesion aid, and a thickener as necessary. , Thermoplastic polymers other than the water-soluble conductive polymer (A), slip agents, leveling agents, ultraviolet absorbers, polymerization inhibitors, antistatic agents, inorganic fillers, organic fillers, surface organically treated inorganic fillers, etc. These various substances may be included.
In addition, in order to further improve the conductivity of the layer formed from the carbon nanotube-containing composition, the carbon nanotube-containing composition can contain a conductive substance. Examples of the conductive material include carbon-based materials such as carbon fiber, conductive carbon black, and graphite.

The carbon nanotube-containing composition in the present invention is a composition containing the water-soluble conductive polymer (A), the carbon nanotube (B), and the solvent (C) as described above. A compound (D), a high molecular compound (E), surfactant (F), and a granular material (G) can be contained.
Hereinafter, these composition ratios will be described.

  The usage ratio of the water-soluble conductive polymer (A) and the solvent (C) is such that the water-soluble conductive polymer (A) is 0.001 to 50 parts by mass with respect to 100 parts by mass of the solvent (C). It is preferable that it is 0.01-30 mass parts. When the water-soluble conductive polymer (A) is 0.001 part by mass or more, sufficient conductivity is easily obtained, and the efficiency of solubilization or dispersion of the carbon nanotube (B) is further improved. Moreover, if a water-soluble conductive polymer (A) is 50 mass parts or less, it will be easy to suppress the fall of the efficiency of solubilization or dispersion | distribution of the carbon nanotube (B) by high viscosity. Further, even when the water-soluble conductive polymer (A) exceeds 50 parts by mass, the conductivity does not increase any more.

  The use ratio of the carbon nanotube (B) and the solvent (C) is preferably 0.0001 to 20 parts by mass of the carbon nanotube (B) with respect to 100 parts by mass of the solvent (C). More preferably, the content is 0.001 to 10 parts by mass. If the said carbon nanotube (B) is 0.0001 mass part or more, the performance by carbon nanotube (B), such as electroconductivity, will fully be acquired easily. Moreover, if a carbon nanotube (B) is 20 mass parts or less, it will be easy to suppress that the efficiency of solubilization or dispersion | distribution of a carbon nanotube (B) falls.

  The use ratio of the basic compound (D) and the solvent (C) is preferably 0.00001 to 10 parts by mass of the basic compound (D) with respect to 100 parts by mass of the solvent (C). More preferably, it is 0.0005-5 mass parts. When the basic compound (D) is 0.00001 parts by mass or more, the solubility of the water-soluble conductive polymer (A) is increased, and the solubilization or dispersion of the carbon nanotubes (B) in the solvent (C) is improved. This promotes the conductivity of the layer formed from the carbon nanotube-containing composition. Moreover, when a basic compound (D) exceeds 10 mass parts, there exists a possibility that the electroconductivity of a water-soluble conductive polymer may fall.

  The use ratio of the polymer compound (E) and the solvent (C) is preferably 0.1 to 400 parts by mass of the polymer compound (E) with respect to 100 parts by mass of the solvent (C). More preferably, it is 5-300 mass parts. When the polymer compound (E) is 0.1 part by mass or more, the film formability, moldability, and strength are further improved. Further, when the polymer compound (E) is 400 parts by mass or less, the solubility of the water-soluble conductive polymer (A) and the carbon nanotube (B) is hardly decreased, and excellent conductivity is easily maintained.

  The use ratio of the surfactant (F) and the solvent (C) is preferably 0.0001 to 10 parts by mass of the surfactant (F) with respect to 100 parts by mass of the solvent (C). More preferably, the content is 0.01 to 5 parts by mass. When the surfactant (F) is 0.0001 part by mass or more, the coating property, conductivity, and solubilization or dispersion of the carbon nanotube (B) are further improved. Further, when the surfactant (F) exceeds 10 parts by mass, the coating property is improved, but a phenomenon such as poor conductivity occurs, and the efficiency of solubilization or dispersion of the carbon nanotube (B) is reduced. There is a risk.

  The use ratio of the particulate matter (G) and the solvent (C) is preferably such that the particulate matter (G) is 0.0001 to 50 parts by weight with respect to 100 parts by weight of the solvent (C). More preferably, it is -30 mass parts. When the particulate material (G) is 0.0001 part by mass or more, it is easy to efficiently form a conduction path in the carbon nanotube (B) in the carbon-containing composite, and it is easy to improve conductivity and transparency. Moreover, if a granular material (G) is 50 mass parts or less, it will be easy to suppress the fall of the efficiency of solubilization or dispersion | distribution of a carbon nanotube (B) and a granular material (G).

[Method for producing carbon nanotube-containing composition]
The water-soluble conductive polymer (A), the carbon nanotube (B), the solvent (C), and the basic compound (D), if necessary, the polymer compound (essential components of the carbon nanotube-containing composition in the present invention) When mixing E), surfactant (F), particulate matter (G), etc., stirring or kneading devices such as ultrasonic waves, homogenizers, spiral mixers, planetary mixers, dispersers, and hybrid mixers are used. Among them, it is preferable to mix the water-soluble conductive polymer (A), the carbon nanotube (B), the solvent (C), or other components, and irradiate this with ultrasonic waves. It is particularly preferable to perform the treatment using a homogenizer in combination (ultrasonic homogenizer).

The conditions of the ultrasonic irradiation treatment are not particularly limited, and the ultrasonic intensity and treatment sufficient to uniformly disperse or dissolve the carbon nanotube (B) or the particulate material (G) in the solvent (C). If it is time. For example, the rated output of the ultrasonic oscillator is preferably 0.1 to 500 watts / cm ² per unit bottom area of the ultrasonic oscillator. The oscillation frequency is preferably 10 to 200 kHz, and more preferably 20 to 100 kHz. In addition, the time for the ultrasonic irradiation treatment is preferably 1 minute to 48 hours, and more preferably 5 minutes to 48 hours. In addition, the temperature of the carbon nanotube-containing composition when performing the ultrasonic irradiation treatment is preferably 60 ° C. or less, and more preferably 40 ° C. or less, from the viewpoint of improving dispersibility.
Moreover, it is preferable to thoroughly disperse or dissolve after the ultrasonic irradiation treatment using a ball kneader such as a ball mill, a bead mill, a vibration mill, a sand mill, or a roll mill.

  When mixing predetermined components, all components may be added at once, or after preparing a concentrated carbon nanotube-containing composition using a small amount of the solvent (C), the remaining components You may dilute to a predetermined density | concentration with a solvent (C). When two or more kinds of solvents (C) are used in combination, a concentrated carbon nanotube-containing composition is prepared using one or more components of the solvent (C) to be used, and then other solvents (C It may be diluted with component C).

<Method for producing carbon nanotube-containing layer>
In the method for producing a carbon nanotube-containing layer of the present invention, a coating film is formed by applying the above-described carbon nanotube-containing composition onto at least one surface of a substrate.

  Examples of the base material that can be used in the photoelectric conversion element of the present invention include a polymer compound, plastic, wood, paper material, ceramics, fiber, nonwoven fabric, carbon fiber, carbon fiber paper, and films, foams, and porous materials thereof. A film, an elastomer, a glass plate, a metal plate, etc. are mentioned.

Specific examples of the polymer compound, plastic and film include, for example, polyethylene, polyvinyl chloride, polypropylene, polystyrene, ABS (acrylonitrile-butadiene-styrene) resin, AS (acrylonitrile-styrene) resin, methacrylic resin, polybutadiene, polycarbonate, Polyarylate, polyvinylidene fluoride, polyester, polyamide, polyimide, polyaramide, polyphenylene sulfide, polyether ether ketone, polyphenylene ether, polyether nitrile, polyamide imide, polyether sulfone, polysulfone, polyether imide, polybutylene terephthalate, polyurethane, These films, foams, elastomers and the like can be mentioned.
These films are preferably subjected to corona surface treatment or plasma treatment on the surface for the purpose of forming a carbon nanotube-containing layer on at least one surface and improving the adhesion of the layer.

  The method of forming a carbon nanotube-containing layer by coating a carbon nanotube-containing composition on a substrate may be any method that can form a desired carbon nanotube-containing layer. For example, a gravure coater, a roll coater, a curtain flow coater Application methods such as spin coater, bar coater, reverse coater, kiss coater, phantom coater, rod coater, air doctor coater, knife coater, blade coater, cast coater, screen coater, spray coating such as air spray, airless spray, etc. Spraying methods, dipping methods such as dipping, and the like are used.

The film thickness of the carbon nanotube-containing layer is preferably 0.01 to 100 μm, and more preferably 0.1 to 50 μm.
When the film thickness of the carbon nanotube-containing layer is 0.01 μm or more, a uniform carbon nanotube-containing layer with good film formability is easily obtained. Moreover, if the film thickness of the carbon nanotube-containing layer is 100 μm or less, the flexibility of the carbon nanotube-containing layer is maintained.

  A method for doping with an acid for further improving the conductivity of the carbon nanotube-containing layer is not particularly limited, and a known method can be used. For example, the doping process can be performed by a process such as immersing the carbon nanotube-containing layer coated on the base material in an acidic solution. Specifically, the acidic solution includes inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid, organic acids such as p-toluenesulfonic acid, camphorsulfonic acid, benzoic acid and derivatives having these skeletons, polystyrene sulfonic acid, polyvinyl It is an aqueous solution containing a polymer acid such as sulfonic acid, poly (2-acrylamido-2-methylpropane) sulfonic acid, polyvinylsulfuric acid and derivatives having these skeletons, or a mixed solution of water-organic solvent. In addition, these inorganic acids, organic acids, and polymer acids may be used alone or in admixture of two or more at any ratio.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited by the following description.
(Production Example 1) Water-soluble conductive polymer (A-1)
Synthesis of poly (2-sulfo-5-methoxy-1,4-iminophenylene):
100 mmol of 2-aminoanisole-4-sulfonic acid was stirred and dissolved in 40 mL of a 4 mol / L triethylamine aqueous solution at 25 ° C., and an aqueous solution of 100 mmol of ammonium peroxodisulfate was added dropwise thereto. After completion of the dropwise addition, the mixture was further stirred at 25 ° C. for 12 hours, and then the reaction product was filtered, washed and dried to obtain 15 g of polymer powder (water-soluble conductive polymer (A-1)). The volume resistance value of this water-soluble conductive polymer (A-1) was 9.0 Ω · cm.

The carbon nanotube (B) used the following.
Carbon nanotube (B): Multi-walled carbon nanotube “trade name: NC7000” manufactured by Nanosil Corporation by CVD (chemical vapor deposition method).
Hereinafter, the carbon nanotube may be abbreviated as “CNT”.

<Carbon nanotube-containing composition>
(Production Example 2) Compositions 1 to 4
The water-soluble conductive polymer (A), carbon nanotube (B), basic compound (D), and polymer compound (E) of Production Example 1 having the composition shown in Table 1 were mixed with 100 masses of water as the solvent (C). The mixture was mixed at room temperature and subjected to ultrasonic homogenizer treatment (Vibra cell 20 kHz, manufactured by SONIC) for 1 hour to prepare compositions 1 to 4.

<Example 1>
(Counter electrode)
An appropriate amount of the carbon nanotube-containing composition 1 is dropped on a titanium substrate and applied by spin coating (coating conditions: 350 rpm × 10 seconds → 1500 rpm × 60 seconds) to form a carbon nanotube-containing layer, and then 80% on a hot plate. A counter electrode was prepared by heat treatment at 2 ° C. for 2 minutes.

(Working electrode)
As a transparent electrode substrate, a glass substrate with a fluorine-doped SnO ₂ (FTO) film is used, and a titanium oxide having an average particle size of 20 nm is applied in a slurry-like dispersion on the surface of the transparent electrode substrate on the FTO film (conductive layer) side. Then, after drying, the oxide semiconductor porous film having a thickness of 7 μm was formed by heat treatment at 450 ° C. for 1 hour. Further, the working electrode was prepared by immersing the ruthenium complex (N3 dye or black dye dye) in an ethanol solution overnight to support the dye.

(Electrolytes)
As the electrolytic solution, a solution obtained by dissolving a predetermined amount of lithium iodide, iodine, and 4-t-butylpyridine in 1-hexyl-3-methylimidazolium iodide (HMIm-I) was used.
In addition, in order to fully infiltrate electrolyte solution in a counter electrode, it was previously immersed in the electrolyte solution of the same composition for one night or more.

Two working electrodes were bonded together using a polypropylene spacer having a predetermined thickness and a thermoplastic resin sheet with a counter electrode sandwiched between them, and the electrolyte was filled from a liquid injection hole provided in advance, thereby closing the hole. At this time, in order to secure a current extraction terminal, the two working electrodes were bonded to each other while being shifted from each other by several mm.
Further, in order to secure a current extraction terminal from the counter electrode, sealing was performed in such a manner that a part of the counter electrode protruded from the short side direction of the working electrode. In order to prevent liquid leakage from the protruding portion of the counter electrode, a UV curable acrylic base resin layer was further formed around the sealing portion.
As described above, a test cell for a photoelectric conversion element having light receiving portions on both sides was produced.

<Example 2>
A counter electrode was produced in the same manner as in Example 1 except that the carbon nanotube-containing composition 2 was used in place of the carbon nanotube-containing composition 1.
Using this counter electrode, a photoelectric conversion element was produced in the same manner as in Example 1.

<Example 3>
An appropriate amount of the carbon nanotube-containing composition 3 is dropped on a glass substrate and applied by spin coating (coating conditions: 350 rpm × 10 seconds → 1500 rpm × 60 seconds) to form a carbon nanotube-containing layer, and then 80% on a hot plate. A transparent electrode substrate was produced by heat treatment at 2 ° C. for 2 minutes. By applying a slurry-like dispersion aqueous solution of titanium oxide having an average particle diameter of 20 nm to the surface of the transparent electrode substrate on the carbon nanotube-containing composite side, drying, and heat-treating at 450 ° C. for 1 hour, a thickness of 7 μm An oxide semiconductor porous film was formed. Further, a photoelectric conversion element was produced in the same manner as in Example 1 except that a working electrode prepared by immersing in an ethanol solution of a ruthenium complex (N3 dye or black dye dye) overnight to carry the dye was used.

<Comparative Example 1>
A counter electrode was produced by forming a conductive film made of platinum on a titanium substrate by a vapor deposition method. A photoelectric conversion element was produced in the same manner as in Example 1 except that the counter electrode thus obtained was used.

<Comparative example 2>
A counter electrode was produced in the same manner as in Example 1 except that the carbon nanotube-containing composition 4 was used in place of the carbon nanotube-containing composition 1.
Using this counter electrode, a photoelectric conversion element was produced in the same manner as in Example 1.

  An evaluation test was performed on the photoelectric conversion elements of Examples and Comparative Examples prepared as described above.

(Photoelectric conversion efficiency)
The photoelectric conversion efficiency was measured about the photoelectric conversion element of each Example and the comparative example.
(Long-term stability)
Changes in photoelectric conversion efficiency between the cell immediately after fabrication and the cell after 1000 hours of light irradiation were examined. A case where the photoelectric conversion efficiency after 1000 hours of light irradiation was within 10% of the initial conversion efficiency was defined as “no change”. The above evaluation results are shown in Table 2.

  In Comparative Example 2, since the dispersibility of carbon nanotubes in the carbon nanotube-containing composition was low, a carbon nanotube-containing layer in which carbon nanotubes were uniformly dispersed on a titanium substrate could not be obtained. Therefore, long-term stability evaluation was not performed.

  The present invention is applicable to a photoelectric conversion element and a method for manufacturing a photoelectric conversion element.

Claims (6)

A working electrode having an oxide semiconductor porous membrane layer carrying a dye supported on at least a part of the conductive layer formed on the substrate, and the conductive layer disposed on the substrate so as to face the working electrode A photoelectric conversion element comprising: a counter electrode formed of; and an electrolyte layer between the working electrode and the counter electrode,
Conductive layer of the working electrode and / or counter electrode, a water-soluble electroconductive polymer having a sulfonic acid group and / or carboxy group (A), and a carbon nanotube-containing layer formed from a composition comprising a carbon nanotube (B) A photoelectric conversion element having Claim conductive layer of the working electrode, water-soluble electroconductive polymer having a sulfonic acid group and / or carboxy group (A), and having a carbon nanotube-containing layer formed from a composition comprising a carbon nanotube (B) 1. The photoelectric conversion element according to 1. Conductive layer of the counter electrode, water-soluble electroconductive polymer having a sulfonic acid group and / or carboxy group (A), as well as claim 1 having a carbon nanotube-containing layer formed from a composition comprising a carbon nanotube (B) The photoelectric conversion element as described in 2. A working electrode having an oxide semiconductor porous membrane layer carrying a dye supported on at least a part of the conductive layer formed on the substrate, and the conductive layer disposed on the substrate so as to face the working electrode And a working electrode and an electrolyte layer between the counter electrode and a method for producing a photoelectric conversion element comprising at least one selected from the working electrode, the counter electrode, and the electrolyte layer A carbon nanotube-containing composition containing a water-soluble conductive polymer (A) having a sulfonic acid group and / or a carboxy group, a carbon nanotube (B) , and a solvent (C) is coated on the surface. The manufacturing method of the photoelectric conversion element which forms a layer. The method for producing a photoelectric conversion element according to claim 4, wherein the carbon nanotube-containing composition further contains a basic compound (D). The method for producing a photoelectric conversion element according to claim 4, wherein the carbon nanotube-containing composition further contains a polymer compound (E).