JP4876450B2 - Porous electrode, composite element having the porous electrode, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode with high light utilization efficiency and high flexibility, and a manufacturing method of the electrode. <P>SOLUTION: The porous electrode has through holes with average diameter d1 of 0.02 to 3&mu;m, and a conductive material selected from a group consisted of conductor and semiconductor is filled in the through holes of a porous film (A) of which porosity is 40 to 90%. The manufacturing method of the porous electrode comprises a process of applying a liquid containing conductive material selected from a group consisted of conductor and semiconductor on a surface of the porous film (A) having through holes with average diameter d1 of 0.02 to 3&mu;m, of which porosity is 40 to 90%, and filling the conductive material in the through holes of the porous film (A). <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

The present invention relates to a porous electrode, a composite element having the porous electrode, and a dye-sensitized solar cell and an electric double layer capacitor including the porous electrode or the composite element as constituent members. The present invention also relates to a method for manufacturing the porous electrode and the composite element.

Photoelectric conversion elements such as solar cells are greatly expected as clean energy sources, and pn junction type silicon solar cells have already been put into practical use. However, since the silicon-based solar cell requires a raw material of high-purity material, and the manufacturing process also requires a high-temperature process or a vacuum process at about 1000 ° C., reduction of manufacturing cost is a major issue. Therefore, in recent years, wet solar cells that do not necessarily require high-purity materials and high-energy processes and perform charge separation by a potential gradient generated at a solid-liquid interface have attracted attention.

In particular, research on so-called dye-sensitized solar cells that improve the photoelectric conversion efficiency by adsorbing light-absorbing dye on the surface of the semiconductor electrode and absorbing visible light with a wavelength longer than the band gap of the semiconductor electrode. Has been actively conducted.

However, conventional dye-sensitized solar cells have extremely poor light utilization efficiency. Conventionally, single crystal and polycrystalline semiconductors used for semiconductor electrodes have a smooth surface and no pores inside. Therefore, the effective area on which the sensitizing dye is supported is only about the same as the electrode area, and only an electrode having a small amount of sensitizing dye can be obtained. In such an electrode, only a monomolecular sensitizing dye supported on the surface of the electrode can contribute to the generation of energy, and the amount of light absorption is 1% or less of incident light even at the maximum absorption wavelength. It wasn't too much. Attempts have been made to make the sensitizing dye multilayer in order to increase the light collecting ability, but generally a sufficient effect has not been obtained.

Under such circumstances, Gretzel et al. Proposed a method of making the titanium oxide electrode porous, supporting a sensitizing dye, and significantly increasing the internal area as means for solving the above problems (Non-patent Document 1). , See Patent Document 1).

Thus, by adsorbing a sensitizing dye on the surface of porous titanium oxide, it has become possible to dramatically improve the amount of injected electrons and increase the light collecting ability.

FIG. 1 is a schematic diagram showing a cross-sectional structure of a dye-sensitized solar cell described in Non-Patent Document 1 described above. Light enters from the transparent substrate 11 side. As the current collecting electrode 12, a transparent conductive film such as a tin oxide film is used because the photoelectric conversion layer exists under the current collecting electrode. Reference numeral 13 denotes a semiconductor electrode layer carrying a sensitizing dye. The semiconductor electrode layer 13 has a porous structure in which titanium oxide having a particle size of approximately 50 nm or less is sintered on the collector electrode 12. Reference numeral 14 denotes an electrolyte solution, which is provided so as to infiltrate the semiconductor electrode layer 13 carrying the pigment. Reference numeral 15 denotes a counter electrode. The counter electrode is provided on the substrate 16.

The dye-sensitized solar cell having the above configuration performs photoelectric conversion by the following mechanism. First, light incident on the dye-sensitized solar cell passes through a light-transmitting current collecting electrode, is absorbed by the sensitizing dye 17 adsorbed on the semiconductor, and generates excited electrons. The generated excited electrons move to the semiconductor and reach the negative electrode through the semiconductor electrode layer 13. The dye that has lost the excited electrons receives electrons from the electrolyte in the reduced state among the redox substances contained in the electrolyte solution and returns to the original state. The redox substance contained in the electrolyte solution that has lost electrons and is in an oxidized state receives electrons from the counter electrode 15 having the platinum film and returns to the reduced state.

B. Oregan, M. Gratzel, Nature, 353, 737 (1991) Japanese Patent Laid-Open No. 1-220380

However, in a conventional dye-sensitized solar cell, when a flexible plastic film is used as the transparent substrate 11, the semiconductor electrode layer made of titanium oxide cannot cope with the flexibility of the film, and cracking or peeling may occur. there were. It is possible to reduce cracking and peeling to some extent by reducing the weight (application amount) of the titanium oxide ultrafine particles and reducing the thickness of the semiconductor electrode layer itself, but in this case, the amount of titanium oxide per light-receiving area is reduced. There is a problem in that the light utilization efficiency decreases because of a decrease.

Several solutions have been proposed for this issue. WO 93/20569 discloses a method of adding a nonionic surfactant “TRITON X-100” to a titanium oxide paste in order to reduce cracks in a coating film. However, the surfactant is added as much as 40% by weight with respect to the titanium oxide, which may inhibit the electron transfer in the titanium oxide film. Japanese Patent Application Laid-Open No. 2003-272722 proposes a method of using about 1% of titanium oxide as a binder with respect to titanium oxide. However, since the amount of the binder added is small, flexibility is inferior. It was enough. Solar energy vol. 29, No. 4, 2003 proposes a method for improving the bonding property between particles after coating titanium oxide particles to which a small amount of a binder is added. However, this method is not preferable because the porous structure of the titanium oxide particles is destroyed by the compressive force.

The present inventors should use a structure like an “intestine” of an animal, which has both high flexibility and surface area, as an electrode having high light utilization efficiency and high flexibility. As a result of intensive studies, the inventors have found that an electrode formed with a porous film having a microporous structure as a template can effectively solve the above-described problems, and completed the present invention.

In one aspect, the present invention has through-holes, an average pore diameter d1 of 0.02 to 3 μm, and a porosity of 40 to 90% in the through-holes of the porous film (A). Provided is a porous electrode filled with a conductive material selected from the group consisting of a body and a semiconductor. The term “porous electrode” is used to distinguish it from the “counter electrode” and “collecting electrode” used in some aspects of the present invention, and the constituent material “porous” is used. It was named after “Quality Film (A)”. The prefix “porous” in the name “porous electrode” is not intended as a structural limitation for this electrode. That is, even an electrode in which all the through holes of the porous film (A) are closed with a conductive substance is referred to as a “porous electrode”.
In another aspect, the present invention provides a through hole in the porous film (A) having through holes, an average pore diameter d1 of 0.02 to 3 μm, and a porosity of 40 to 90%. A porous film having through-holes having an average pore diameter smaller than the average pore diameter d1 of the porous film (A) on one side of a porous electrode filled with a conductive material selected from the group consisting of a body and a semiconductor ( A composite element in which B) is laminated is provided.
In another aspect, the present invention provides a first electrode and a second substrate facing each other, and a counter electrode, a porous electrode and a current collecting electrode arranged between the two substrates in order from the first substrate, and A dye-sensitized solar cell having an electrolyte disposed between a counter electrode and a collecting electrode via a porous electrode, wherein the porous electrode has a through-hole and an average pore diameter d1 of 0. In the through hole of the porous film (A) having a porosity of 40 to 90% and a semiconductor filled, and the second substrate is a transparent substrate, Provided is a dye-sensitized solar cell, wherein the semiconductor and the counter electrode are not in contact with each other, and a sensitizing dye is supported on the surface of the semiconductor.
In another aspect, the present invention provides a first electrode and a second substrate facing each other, and a counter electrode, a porous electrode and a current collecting electrode arranged between the two substrates in order from the first substrate, and An electric double layer capacitor having an electrolyte disposed between the counter electrode and the collecting electrode via the porous electrode, the porous electrode having a through hole and an average pore diameter d1 of 0 0.02 to 3 μm, and the porous film (A) having a porosity of 40 to 90% is an electrode filled with a conductor, and the conductor and the counter electrode are in contact with each other. An electric double layer capacitor is provided.
In another aspect, the present invention provides a conductor and a semiconductor on the surface of the porous film (A) having through holes, an average pore diameter d1 of 0.02 to 3 μm, and a porosity of 40 to 90%. There is provided a method for producing a porous electrode, which comprises a step of applying a liquid containing a conductive substance selected from the group consisting of and filling the through hole of a porous film (A) with the conductive substance.
In another aspect, the present invention provides a through hole in the porous film (A) having through holes, an average pore diameter d1 of 0.02 to 3 μm, and a porosity of 40 to 90%. Applying a polymer solution containing a polymer and a solvent to one side of a porous electrode filled with a conductive material selected from the group consisting of a body and a semiconductor to form a polymer solution layer; And production of a composite element having a step of removing the solvent from the polymer solution layer to form a porous film (B) having through holes having an average pore diameter smaller than the average pore diameter d1 of the porous film (A). Provide a method.

The porous electrode of the present invention has high light utilization efficiency and high flexibility. The composite element of the present invention has high light utilization efficiency and high flexibility. Furthermore, the dye-sensitized solar cell or the electric double layer capacitor having the porous electrode or the composite element of the present invention as a constituent member has high light utilization efficiency and high flexibility.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is a schematic diagram showing a cross-sectional structure of a dye-sensitized solar cell using the porous electrode of the present invention. In FIG. 2, the code | symbol 21 shows a transparent substrate and the code | symbol 22 shows a current collection electrode. Reference numeral 23 represents a porous electrode of the present invention on which a sensitizing dye 27 is supported. The conductive substance 231 in the porous electrode 23 is a substance having a large surface area per unit volume, which is formed by densely filling a particulate conductive substance into the through holes of the porous film (A) 232. is there. Reference numeral 24 denotes an electrolyte solution, which is provided so as to infiltrate the porous electrode 23 carrying the pigment. Reference numeral 25 denotes a counter electrode, which is provided on the substrate 26.

Although the glass substrate and metal foil which have flexibility can also be used as the transparent substrate 21, use of a film substrate is preferable for production of a flexible solar cell module. Further, since the transparent substrate 21 functions as a light incident substrate, it is preferably a transparent film using a material having a HAZE value of 2% or less per 100 μm thickness. Such films include cellulose films such as diacetate cellulose film, triacetate cellulose film, tetraacetyl cellulose film, polyethylene film, polypropylene film, polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, polyethylene terephthalate film, polycarbonate. Film, Polyethylene naphthalate film, Polyethersulfone film, Polyetheretherketone film, Polysulfone film, Polyetherimide film, Polyimide film, Polyamideimide film, Polyamide film, Polyarylate film, Cycloolefin polymer film, Norbornene resin film , Polystyrene film Rubber hydrochloride film, nylon film, a polyacrylate film, polyvinyl fluoride films, such as polytetrafluoroethylene films may be used. Among these, a polyethylene terephthalate film, a polyethylene naphthalate film, a polyether sulfone film, a polyimide film, a polyarylate film, a cycloolefin polymer film, and a norbornene resin film are particularly preferably used because they are excellent in toughness and heat resistance.

The collector electrode 22 disposed on one surface of the transparent substrate 21 is a conductor layer and functions as a negative electrode of the photoelectric conversion element.

Preferred conductors include transparent conductive metal oxides such as indium tin oxide (ITO), fluorine-doped tin oxide (FTO), indium oxide (IO), tin oxide (SnO ₂ ) and the like. Examples include those doped with antimony, metals such as aluminum, nickel, cobalt, platinum, silver, gold, copper, molybdenum, titanium, tantalum, alloys containing these, or various carbon materials such as graphite. One of these can be used alone, or two or more can be used in combination.

The average thickness of the current collecting electrode 22 is appropriately set depending on the material, use, and the like, and is not particularly limited. For example, it can be as follows.
When the current collecting electrode 22 is composed of the metal oxide (transparent conductive metal oxide), the average thickness is preferably 0.05 to 5 μm, and preferably 0.1 to 1.5 μm. It is more preferable.

When the current collecting electrode 22 is composed of the above-mentioned metal or an alloy containing these or various carbon materials, the average thickness is preferably 0.01 to 1 μm, preferably 0.03 to 0.1 μm. More preferably.

The collector electrode 22 preferably has a low surface resistance value. The range of the surface resistance value is preferably 50 Ω / cm ² or less, more preferably 30 Ω / cm ² or less. Although there is no restriction | limiting in particular in a lower limit, Usually, it is 0.1 ohm / cm < ² > or more.

The light transmittance of the current collecting electrode 22 is preferably high. A preferable light transmittance range is 50% or more, and more preferably 80% or more. This is because sufficient light can be incident on the electrode 231. When the transparent collector electrode 22 is used, light is preferably incident from the side of the collector electrode 22 on which the electrode 23 carrying the sensitizing dye is deposited.

The method for producing a porous electrode according to the present invention includes a step of applying a liquid containing a conductive substance on the surface of the porous film (A) 232 and filling the through hole of the porous film (A) with the conductive substance. including. The liquid containing the conductive substance may be a liquid conductive substance or may be a liquid in which the conductive substance is dissolved in a solvent. Alternatively, a liquid in which conductive material particles are dispersed in a solvent may be used. Specifically, a method of applying a liquid containing a conductive substance to the porous film (A) using a doctor blade or bar coater and drying, a spray method, a dip coating method, a screen printing method, a gravure printing method, a spin method The method of apply | coating and drying by methods, such as a coating method, is mentioned. In applying and drying, in order to remove the dispersion medium more efficiently, it is also effective to suck the dispersion medium from the opposite surface of the application surface during and / or after application of the liquid containing the conductive substance. In addition, when the porous film (A) is filled with the conductive material using the dispersion liquid of the conductive material particles, the adhesion between the conductive material particles is improved by heat treatment or pressing after the filling. It is also effective. The filling amount of the conductive material into the porous film (A) can be controlled by repeating the coating amount of the liquid containing the conductive material, coating drying and pressing.

The filling amount of the conductive material 231 in the porous film (A) 232 is preferably in the range of 0.5 to 500 g / m ² , more preferably 5 to 250 g / m ² , and still more preferably. 25 to 150 g / m ² , and the most preferable range is 50 to 100 g / m ² . This is because, within this range, a sufficient photoelectric conversion effect is obtained and the flexibility is excellent.

When the conductive material is an aggregate of conductive material particles, a porous electrode is manufactured using a liquid in which the conductive material particles are dispersed in a solvent. The particles of the conductive material particles in the dispersion at this time are manufactured. The diameter is preferably in the range of 1 to 1000 nm. This is because within this range, the electrolyte can sufficiently penetrate into the porous film (A) 232 to obtain excellent photoelectric conversion characteristics. A particularly preferable range of the particle diameter of the conductive substance particles is 5 to 100 nm.

The conductive substance 231 is a substance selected from the group consisting of a conductor and a semiconductor, and may be a conductor, a semiconductor, or a combination (mixture) of both.
Semiconductors include metal elements such as Cd, Zn, In, Pb, Mo, W, Sb, Bi, Cu, Hg, Ti, Ag, Mn, Fe, V, Sn, Zr, Sr, Ga, Si, and Cr. Oxides; perovskites such as SrTiO ₃ and CaTiO ₃ ; sulfides such as CdS, ZnS, In ₂ S ₃ , PbS, Mo ₂ S, WS ₂ , Sb ₂ S ₃ , Bi ₂ S ₃ , ZnCdS ₂ and Cu ₂ S Metal chalcogenides such as CdSe, In ₂ Se ₃ , WSe ₂ , HgS, PbSe, CdTe; other GaAs, Si, Se, Cd ₂ P ₃ , Zn ₂ P ₃ , InP, AgBr, PbI ₂ , HgI ₂ , BiI ₃ A composite containing at least one selected from the conductive materials, for example, CdS / TiO ₂ , CdS / AgI, Ag ₂ S / AgI, CdS / ZnO, CdS / HgS, CdS / Pb S, ZnO / ZnS, ZnO / ZnSe, CdS / HgS, CdS x / CdSe 1-x, CdS x / Te 1-x, CdSe x / Te 1-x, ZnS / CdSe, ZnSe / CdSe, CdS / ZnS, Examples thereof include TiO ₂ / Cd ₃ P ₂ , CdS / CdSeCd _y Zn _1-y S, CdS / HgS / CdS, and the like. Of these, TiO ₂ is preferred in that it can avoid photodissolution in the electrolyte solution and achieve high photoelectric conversion characteristics in the Gretzel cell.
Examples of the conductor include carbonaceous powders such as graphite, activated carbon, and carbon black, and metals such as copper, iron, aluminum, and gold.
When the porous electrode of the present invention is used as an element of an electric double layer capacitor, it is common to use a conductor as the conductive substance, and as the conductor, carbonaceous powder is preferable, and activated carbon is particularly preferable. . From the viewpoint of the electrostatic capacitance of the electric double layer capacitor, the specific surface area of the carbonaceous powder is preferably from 700~2500m ² / g, particularly preferably 1000~1800m ² / g. In addition to the activated carbon powder, materials having a large specific surface area such as carbon black and polyacene can be preferably used. In particular, it is preferable to use a mixture of activated carbon powder having a high specific surface area and carbon black.

As the porous film (A) 232, a porous film for a filter for filtration (membrane filter), a known porous film for a primary or secondary battery separator, and the like can be used. The porous film (A) must have through holes (voids) that lead from the surface of the film to the back so that the electrolyte in the electrolyte solution can pass through. The through-hole which a porous film (A) has may be a hole which penetrates the other surface linearly from one surface of the film. The through-hole is defined in the porous film (A) by a three-dimensional network structure formed of the material constituting the film, and communicates from one surface of the film to the other surface. It may be a three-dimensional network-like space. As an example of the porous film which has a through-hole which consists of such a three-dimensional network-like space, the porous film described in the claim and the specification of US Patent Publication No. 2002-0192454 can be given.

The material constituting the porous film (A) 232 includes polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate; polyamides; polyimide; acetalized polyvinyl alcohol (vinylon); vinyl chloride-vinyl acetate copolymer. Polyphenylene sulfide is preferred. The porous material may be a single material or a mixture of two or more types.

The thickness of the porous film (A) 232 is not particularly limited, but is generally 0.1 to 50 μm. If the porous film (A) 232 is too thick, the electrolyte travel distance becomes long, and the battery performance tends to be lowered.

The porosity of the porous film (A) 232 is 40 to 90%. If the porosity is lower than 40%, the amount of the conductive material supported is reduced and the movement of the electrolyte solution is hindered, thereby reducing the energy conversion efficiency. If the porosity is 90% or more, it is the same as using a substrate that does not substantially have through holes, resulting in poor energy efficiency and poor flexibility.

The porosity of the porous film (A) is defined by porosity = (1−V1 / V) × 100. Here, V1 is the true volume of the film, and V is the apparent volume of the same film. The porosity can be determined by the following method. First, the porous film is punched into a disk shape having a diameter of 32 mm, and the apparent volume (V) of the obtained test piece is measured by an underwater substitution method. On the other hand, the true volume (V1) of a similar test piece taken from the same porous film is measured using an autopicometer Accupic 1320 model manufactured by Shimadzu Corporation. The porosity is calculated using the obtained V value and V1 value.

The average pore diameter d1 of the porous film (A) 232 is 0.02 to 3 μm, preferably 0.04 to 1 μm. If the average pore diameter d1 is too small, it is difficult to fill the conductive material 231. If the average pore diameter d1 is too large, the surface area per unit volume of the conductive material becomes small, and the photoelectric conversion effect becomes insufficient.

The average pore diameter d1 of the porous film (A) is a value obtained by doubling the average pore radius r (μm) obtained by the mercury intrusion method according to JIS K1150, that is, 2r. The average pore radius is measured using Autopore III9420 (manufactured by MICROMERITICS).

When the conductive material particles are filled into the pores of the porous film (A) 232 to form a porous electrode, the lower limit of the pore size of the porous film (A) 232 is substantially equal to the particle size of the conductive material particles. It is preferable.

Such a porous film (A) 232 can generally have a Gurley value (according to JIS P8117) of 10 to 500 seconds / 100 cm ³ per 25 μm thickness.

A porous electrode filled with a conductive substance in the through-hole of the porous film (A) as described above has high light utilization efficiency and excellent flexibility. In addition, it is resistant to tensile stress, and it undergoes severe mechanical deformation such as the process of pasting with the collector electrode using the roll-to-roll method, the supporting process of the sensitizing dye described later, and the slit process of cutting to the desired width. Even if it passes through the process accompanied by, it is not destroyed and is excellent in productivity.
In the present invention, the entire amount of the conductive substance may be accommodated in the through holes in the porous film (A), and a part of the conductive substance is on the surface of the porous film (A). May be present. An embodiment in which an appropriate amount of conductive material is present on the surface of the porous film (A) is one of the preferred embodiments. However, if it exists on the surface of the porous film in an excessive amount, cracks are likely to occur when the porous electrode is deformed.

In the porous electrode of the present invention, the conductive material is preferably filled with a density gradient in the thickness direction of the porous film (A). The degree of the density gradient is preferably such that the value of the ratio of the density of the conductive material on one surface of the porous film (A) to the density of the conductive material on the other surface is 2 or more. More preferably, it is more preferably 5 or more. Further, the value of this ratio is preferably 15 or less, more preferably 10 or less. The porous electrode formed by filling the conductive material with a density gradient in the thickness direction of the porous film (A) has higher flexibility. In view of the principle of operation when actually functioning as a battery, in view of the fact that the diffusion gradient of the electrolyte provides electromotive force, the surface facing the collector electrode 22 is filled with the conductive material in the porous film (A). By setting the porous electrode so that the surface having a high rate and the surface facing the counter electrode 25 are surfaces having a low conductive material filling rate, further increase in efficiency of light utilization can be expected.

The density gradient of the conductive material in the thickness direction of the porous film (A) is determined by adjusting the conductive material particle diameter, the concentration of the conductive material particle dispersion or the hydrogen ion concentration, the pore diameter of the porous film, the porous It can be controlled by application conditions (line speed, drying speed, etc.) of the conductive material particle dispersion on the film. If the particle size of the conductive material particles is too small compared to the pore size of the porous film, the density gradient is difficult to be applied. If the particle size is too large, the conductive material particles tend not to be filled into the through holes of the porous film. Even if conductive material particles with a sufficiently small particle size are used, if the concentration of the dispersion liquid is high or the conductive material particles are secondary aggregated due to the influence of the hydrogen ion concentration, etc. It may be difficult to fill the conductive material particles as in the case where the material particle size is large.

As a method of measuring the density gradient of the conductive substance, there is a method of measuring the spatial distribution of the element concentration of interest with an EPMA (Electron Probe Microanalyzer) while observing the cross section of the porous electrode 23 with an electron microscope. it can. In addition, TOF-SIMS, Auger electron spectroscopy, or the like may be used.

Further, by using a porous film (A) in which the inner wall of the through hole is coated with a metal, electrons injected into the conductive material can be efficiently guided to the current collecting electrode. The use of such a porous film (A) is particularly effective when the conductive material particles are isolated in the porous film (A), or when the mutual adhesion is insufficient and the grain boundary resistance is large. is there. FIG. 3 shows that electrons (e−) excited by the sensitizing dye 27 in the conductive material 231 are transmitted to the metal coating 34 through the conductive material 231 in the pores of the porous film (A), and are collected. A mode that it is conveyed toward an electric electrode is shown typically.

A known method can be used as a method of forming a metal coating on the pore inner wall of the porous film. For example, a vapor deposition method (JP-A-60-261502), a metal electroless plating method (JP-A-64-56106, JP-A-6-304454), a sputtering method (JP-A-63-152404), and the like can be mentioned. It is done.

Among these, a particularly preferable method is a method of performing electroless metal plating after etching the inner wall surface of the through hole of the porous film as proposed in JP-A-6-304454. According to this method, the inner wall surface of the through-hole and the metal coating can be firmly adhered, so that a porous electrode that is superior in flexibility can be obtained.

When high-concentration etching treatment is performed on a resin, carbon radicals, carboxyl groups (—COOH), carbonyl groups (—C═O), hydroxyl groups are obtained by dehydrogenation of the resin, oxidation of the resin, cleavage of the resin, hydrolysis, etc. Functional groups capable of chemically bonding to metal such as (—OH) group, sulfone group (—SO ₃ H), and nitrile group (—CN) are generated on the resin side. By combining these functional groups with metal atoms or metal ions (M), for example, -CM group, -COOM group, -COM group, -OM group, -SO ₃ M group, -CNM group are formed. The metal chemically bonds to the resin.

The etching treatment solution may be any one that can introduce a functional group capable of chemically bonding to a metal into the resin, such as a high concentration chromic acid / sulfuric acid solution, a high concentration sulfuric acid / nitric acid mixture, Examples include strong bases such as potassium hydroxide, ammonium hydrogen fluoride, nitric acid and the like. The etching treatment solution only needs to have a concentration capable of introducing a functional group into the resin. Specifically, a chromic acid / sulfuric acid solution having a chromic acid concentration of 30 to 50% and a sulfuric acid concentration of 10 to 40%, 10 to 30% Strong sulfuric acid, sulfuric acid / nitric acid mixed solution composed of 10-30% sulfuric acid and 10-30% nitric acid, ammonium hydrogen fluoride / nitric acid mixed solution composed of 10-40% ammonium hydrogen fluoride and 40-70% nitric acid. It is done.

In the electroless treatment for chemically bonding the metal to the pore inner wall of the porous film, it is desirable to chemically bond the metal through a catalyst that promotes the reduction reaction of the metal. It is desirable to interpose a catalyst metal such as Pd or Pd, Sn that becomes a catalyst for electroless treatment. In this case, the catalytic metal is once bonded to the inner wall of the hole.

When the resin to which the catalytic metal is bonded is treated with a metal solution containing a metal ion, a complexing agent, and a reducing agent, a reduction reaction of the metal ion occurs on the surface of the catalytic metal, and a metal layer is uniformly formed. There is a case.

The metal salt for generating metal ions during the electroless treatment is not particularly limited as long as it is water-soluble such as sulfate, chloride, and nitrate. Examples of the metal that covers the pore inner wall of the porous film by electroless treatment include at least one of Ni, Co, Fe, Mo, W, Cu, Re, Au, and Ag. As the reducing agent, known compounds such as formalin and glucose are used in addition to phosphorus compounds such as sodium hypophosphite and boron compounds such as hydrogen borohydride. The complexing agent is not particularly limited as long as it can form a stable complex with a metal ion, and examples thereof include ammonia, citric acid, tartaric acid, oxalic acid and the like.

The electroless plated porous film may be further subjected to electrolytic treatment. Examples of the metal to be electrolytically treated include Cr, Zn, Ag, Au, Pt, Al, Mn, Bi, Se, Te, Cd, Ir, Ti, and Ni.

The thickness of the metal coating is not particularly limited, but is preferably about 0.001 μm to 1 μm. If the metal film is too thin, the conductivity tends to be difficult to maintain, and if it is too thick, the flexibility may be impaired.

FIG. 4 is a schematic diagram showing a cross-sectional structure of a dye-sensitized solar cell using the composite element of the present invention. The porous film (B) 432 is a layer that does not substantially contain a conductive material, and is a so-called separator having a function of preventing a short circuit due to physical contact between the conductive material 231 and the counter electrode 25. A device in which the porous electrode 23 and the porous film (B) 432 are combined is a composite device 43.

The composite element of the present invention comprises a porous electrode filled with a conductive substance in the through-hole of the porous film (A), and a porous film (B) laminated on one surface thereof.
The porous film (B) 432 needs to have a through hole so that the conductive substance 231 and the counter electrode 45 are isolated from each other so as not to be short-circuited, and electrolyte ions can move.

The material constituting the porous film (B) 432 includes polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate; polyamides; polyimide; acetalized polyvinyl alcohol (vinylon); vinyl chloride-vinyl acetate copolymer Polyphenylene sulfide is preferred. The porous material may be a single material or a mixture of two or more types.

The thickness of the porous film (B) 432 is not particularly limited, but is preferably 0.1 to 10 μm from the viewpoint of ease of movement of the electrolyte and insulation.

The porous film (B) 432 preferably has a porosity of 40 to 90% from the viewpoint of ease of movement of the electrolyte.

If the average pore diameter of the porous film (B) is larger than the average pore diameter d1 of the porous film (A), when stress is applied to the composite element, only the porous film (A) contracts and the porous film There is a possibility that the conductive material filled in (A) protrudes from the porous film (A), contacts the counter electrode 45 through the through hole of the porous film (B), and is short-circuited. Therefore, the porous film (B) has pores having an average pore diameter smaller than the average pore diameter d1 of the porous film (A).
The average pore diameter of the porous film (B) is preferably 0.002 μm to 0.7d1. Here, d1 is the average pore diameter of the porous film (A). If the average pore size of the porous film (B) is too small, the electrolyte may be difficult to move.

The manufacturing method of a composite element is divided roughly into two types.
First, a porous material is first prepared by filling a through hole in the porous film (A) with a conductive substance, and then a porous film (B) is formed on one surface of the porous electrode. It is a method of arrangement. Specifically, for example, on one side of the porous electrode in which the through hole of the porous film (A) having the through hole is filled with a conductive material selected from the group consisting of a conductor and a semiconductor. A method of providing a porous film (B) by applying a polymer solution in which a polymer is dissolved in a solvent to form a polymer solution layer and then removing the solvent from the polymer solution layer. is there.

The second is a method of first producing a laminated porous film comprising a porous film (A) and a porous film (B), and then filling only a through-hole of the porous film (A) with a conductive material. It is.
Specifically, for example, the conductive material is applied to the surface of the porous film (A) in the laminated porous film in which the porous film (A) and the porous film (B) produced by an appropriate method are laminated. The method of having the process of apply | coating the liquid which contains and filling a through-hole of a porous film (A) with an electroconductive substance is mentioned. However, in this case, it is necessary to prevent the porous film (B) from being filled with a conductive substance. For example, as a liquid containing a conductive substance, a conductive substance particle dispersion having a particle diameter smaller than the average pore diameter of the porous film (A) and larger than the average pore diameter of the porous film (B) may be used.

Although there is no restriction | limiting in particular about the method of obtaining the lamination | stacking porous film which consists of porous film (B) 432 and porous film (A) 232, The method of following (1), (2) and (3) is illustrated. Is done.
(1) Method of laminating separately prepared porous film (A) and porous film (B) by a known method such as thermal bonding or dry laminating method (2) Two types of resin materials containing filler Are laminated by a coextrusion method to obtain a two-layer coextrusion, and then stretched to make each layer porous (3) as disclosed in JP-A-9-38475 and JP-A-2003-40999, On the surface of one porous film, a solution of the material of the other porous film is applied to form a solution layer, and then the solvent is removed from the solution layer to form a new porous layer on the original porous film. Examples include a method of forming a quality film.
In order to obtain a composite element that satisfies the requirement that the average pore diameter of the porous film (B) is smaller than the average pore diameter d1 of the porous film (A), in the method (1), for example, the porous film (A A porous film having an average pore size smaller than the average pore size d1) may be selected. In the method (2), for example, a filler having a particle size smaller than the particle size of the filler to be blended with the porous film (A) material may be blended with the porous film (B) material. Further, in the method (3), for example, the concentration of the solution to be applied may be adjusted, or the solution may be rapidly cooled after the solution is applied to cause the solute and the solvent to undergo microphase separation.

As the sensitizing dye to be carried on the surface of the conductive substance, any dye that is commonly used in conventional dye-sensitized photoelectric conversion elements can be used. Such dyes are, for example, RuL ₂ (H ₂ O) 2 type ruthenium-cis-diaqua-bipyridyl complexes, ruthenium-tris (RuL ₃ ), ruthenium-bis (RuL ₂ ), osnium-tris (OsL ₃ ). , An osmium-bis (OsL ₂ ) type transition metal complex, zinc-tetra (4-carboxyphenyl) porphyrin, iron-hexocyanide complex, phthalocyanine, and the like. As organic dyes, 9-phenylxanthene dyes, coumarin dyes, acridine dyes, triphenylmethane dyes, tetraphenylmethane dyes, quinone dyes, azo dyes, indigo dyes, cyanine dyes, merocyanine dyes Examples thereof include dyes and xanthene dyes. Among these, ruthenium-bis (RuL ₂ ) derivatives are particularly preferable because they have a broad absorption spectrum in the visible light region.

Examples of the method of supporting the sensitizing dye on the surface of the conductive material include a method of immersing a porous electrode filled with the conductive material in a solution in which the sensitizing dye is dissolved. Any solvent can be used as the solvent for the solution as long as it can dissolve the sensitizing dye, such as water, alcohol, toluene, and dimethylformamide. Further, when the porous electrode is immersed in the sensitizing dye solution, it can be heated or an ultrasonic wave can be applied. After removing the porous electrode from the sensitizing dye solution, the porous electrode may be washed with alcohol at an appropriate temperature (for example, room temperature or boiling point) in order to remove the sensitizing dye not fixed to the conductive material. desirable.

The loading amount of the sensitizing dye in the conductive material may be in the range of 1 × 10 ⁻⁸ to 1 × 10 ⁻⁶ mol / cm ² , and in particular 1 × 10 ^{−8 to} 9.0 × 10 ^{−. 7} mol / cm ² is preferred. Within this range, the effect of improving the photoelectric conversion efficiency can be obtained economically and sufficiently.

When producing the dye-sensitized solar cell or the electric double layer capacitor by arranging the porous electrode or the composite element of the present invention between the counter electrode and the collector electrode, in general, the counter electrode and the collector electrode There is an electrolyte solution in between. The electrolyte solution is also present inside the through hole of the porous electrode or the composite element. The electrolyte solution is composed of an electrolyte and a solvent.
As the electrolyte, LiI, NaI, KI, CsI, and an iodide such as iodine salt of CaI metal iodide such as _2, and tetraalkylammonium iodide, pyridinium iodide, imidazolium iodide and quaternary ammonium compounds, I combination of _{2; LiBr, NaBr, KBr,} CsBr, CaBr metal bromide such as _2, and tetraalkyl ammonium bromide, and bromide such as bromine salts of quaternary ammonium compounds such as pyridinium bromide, combination of Br _2; ferrocyanide acid Metal complexes such as salt-ferricyanate and ferrocene-ferricinium ions; sulfur compounds such as sodium polysulfide and alkylthiol-alkyldisulfides; viologen dyes, hydroquinone-quinones and the like. Among these, LiI, pyridinium iodide, and a combination of imidazolium iodide and I ₂ are preferable. Two or more of the above electrolytes may be mixed and used.

As the solvent, a compound that exhibits a low viscosity, an improved ion mobility, a high dielectric constant, and an excellent ion conductivity that improves the effective carrier concentration is desirable. Examples of such solvents include carbonate compounds such as ethylene carbonate and propylene carbonate; heterocyclic compounds such as 3-methyl-2-oxazolidinone; ether compounds such as dioxane and diethyl ether; ethylene glycol dialkyl ether, propylene glycol dialkyl ether, polyethylene Chain ethers such as glycol dialkyl ether and polypropylene glycol dialkyl ether; alcohols such as methanol, ethanol, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, polyethylene glycol monoalkyl ether and polypropylene glycol monoalkyl ether; ethylene glycol, Propylene glycol, polyethylene glycol, polyp Propylene glycol, polyhydric alcohols such as glycerin; acetonitrile, glutarodinitrile, methoxy acetonitrile, propionitrile, nitrile compounds such as benzonitrile; like water; dimethyl sulfoxide, aprotic polar substances such as sulfolane.

The electrolyte concentration in the electrolyte solution is preferably about 0.1 to 5 mol / l. Further, the addition concentration when iodine is added to the electrolyte solution is preferably about 0.01 to 0.5 mol / l.

The electrolyte solution includes J.I. Am. Ceram. Soc. , 80 (12) 3157-3171 (1997), basic compounds such as ter-butylpyridine, 2-picoline, and 2,6-lutidine can also be added. The addition concentration when adding the basic compound is preferably about 0.05 to 2 mol / l.

A solid electrolyte may be used in place of the electrolyte solution. Here, the solid electrolyte is a mixture of an electrolyte and an ion conductive polymer compound. Examples of the ion conductive polymer compound include polar polymer compounds such as polyethers, polyesters, polyamines, and polysulfides.

Moreover, it may replace with electrolyte solution and may use the gel electrolyte produced using electrolyte, a solvent, and a gelatinizer. As the gelling agent, a polymer gelling agent is preferably used. Examples thereof include polymer gelling agents such as crosslinked polyacrylic resin derivatives, crosslinked polyacrylonitrile derivatives, polyalkylene oxide derivatives, silicon resins, and polymers having a nitrogen-containing heterocyclic quaternary compound salt structure in the side chain.

Furthermore, a molten salt gel can be used instead of the electrolyte solution. In this case, the molten salt is an electrolyte. As the molten salt gel, one obtained by adding a normal temperature type molten salt to a gel material can be used. As room temperature type molten salts, nitrogen-containing heterocyclic quaternary ammonium salt compounds such as pyridinium salts and imidazolium salts are preferably used.

The counter electrode functions as a positive electrode when the photoelectric conversion element is a photoelectrochemical cell, and generally comprises a support substrate and a conductive layer made of a conductive material formed thereon. Examples of conductive materials include metals (for example, platinum, gold, silver, copper, aluminum, magnesium, indium, etc.), carbon, and conductive metal oxides (indium-tin composite oxide, tin oxide doped with fluorine, etc.) Is mentioned. Of these, platinum, gold, silver, copper, aluminum and magnesium are preferred. The support substrate is preferably a glass substrate or a plastic substrate. The conductive layer is formed by applying or vapor-depositing the conductive material on a support substrate. The thickness of the conductive layer is not particularly limited, but is preferably 3 nm to 10 μm. The surface resistance is low Moderately of the counter electrode, preferably at 50 [Omega / cm ² or less, more preferably 20 [Omega / cm ² or less.

The substrate 26 can use the same material as the transparent substrate 21. Since the translucency of the substrate may be either transparent or opaque, a metal foil such as nickel, zinc or titanium can be used. However, if it is transparent, light can be incident from the substrates 21 and 26 on both sides. Therefore, it is preferable.

Since the porous electrode of the present invention or the composite element in which the porous film (B) is laminated on the porous electrode is excellent in photoelectric conversion efficiency and excellent in flexibility, a dye-sensitized solar cell or an electric double layer is used. It is suitably used as a component member of a capacitor.

A dye-sensitized solar cell according to one aspect of the present invention includes a first and second substrates facing each other, a counter electrode disposed between the two substrates in order from the first substrate, and a porous electrode And a collector electrode, and a dye-sensitized solar cell having an electrolyte disposed between the counter electrode and the collector electrode via a porous electrode, the porous electrode having a through hole The second substrate is an electrode in which a semiconductor is filled in a through hole of a porous film (A) having an average pore diameter d1 of 0.02 to 3 μm and a porosity of 40 to 90%. Is a transparent substrate in which the semiconductor and the counter electrode are not in contact, and a sensitizing dye is supported on the surface of the semiconductor. In order to reliably achieve non-contact between the semiconductor and the counter electrode, the average pore diameter d1 of the porous film (A) laminated on the surface of the porous electrode between the porous electrode and the counter electrode It is preferable that the porous film (B) which has a through-hole whose average pore diameter is smaller than is arrange | positioned. This improved embodiment is an application of the composite element of the present invention. It is preferable that the through hole of the porous film (B) is not substantially filled with a conductive substance. In addition, it is preferable that the through-hole of a porous film (A) is filled with the conductor with the semiconductor.

A dye-sensitized solar cell is placed in a container by sandwiching a counter electrode, a porous electrode (however, a conductive material contains at least a semiconductor) or a composite element, and a collector electrode in this order between a substrate and a transparent substrate. It is prepared by injecting an electrolyte solution or an equivalent thereof into a container, preferably under reduced pressure, sufficiently impregnating a porous electrode or a composite element with the electrolyte solution or an equivalent thereof, and then sealing the container. Can do. When a composite element in which a porous film (B) is laminated on a porous electrode is used, the porous film (B) side of the composite element and the counter electrode are laminated. In the production of a dye-sensitized solar cell, a porous electrode carrying a sensitizing dye is used.

An electric double layer capacitor according to one aspect of the present invention includes a first substrate and a second substrate facing each other, a counter electrode disposed between the two substrates in order from the first substrate, a porous electrode, An electric double layer capacitor having a current collecting electrode and an electrolyte disposed between the counter electrode and the current collecting electrode via the porous electrode, the porous electrode having a through hole; An average pore diameter d1 is 0.02 to 3 μm, and a porous film (A) having a porosity of 40 to 90% is an electrode filled with a conductor, and is opposed to the conductor. The electric double layer capacitor is not in contact with the electrode. In order to reliably achieve non-contact between the conductor and the counter electrode, the average pore diameter of the porous film (A) laminated on the surface of the porous electrode between the porous electrode and the counter electrode It is preferable that the porous film (B) which has a through-hole whose average hole diameter is smaller than d1 is arrange | positioned. This improved embodiment is an application of the composite element of the present invention. The conductor is preferably carbonaceous powder, and more preferably activated carbon.

An electric double layer capacitor is, for example, an electric double layer capacitor sandwiched between two substrates in the order of a counter electrode, a porous electrode (however, a conductive substance is a conductor) or a composite element, and a collecting electrode. The container is housed in a container, and a nonaqueous electrolyte solution or an equivalent thereof is injected into the container preferably under reduced pressure. After the electrolyte solution or the equivalent is sufficiently impregnated into the porous electrode or the composite element, the container is It can be manufactured by sealing. When a composite element in which a porous film (B) is laminated on a porous electrode is used, the porous film (B) side of the composite element and the counter electrode are laminated.

Hereinafter, based on an Example, this invention is demonstrated more concretely. However, the present invention is not limited to the following examples.

(1) Film thickness measurement The film thickness was measured at 10 points in the width direction and length direction using a digital micrometer VL-50 manufactured by Mitsutoyo, and the average value of all measured values was calculated. did. The average value was taken as the thickness of the film.

(2) Average pore diameter Based on JIS K1150, the average pore radius r (μm) was measured with Autopore III9420 (manufactured by MICROMERITICS) by mercury porosimetry, and the average pore diameter was 2r.

(3) The porosity film is punched into a disk shape having a diameter of 32 mm, and the apparent volume (V) is measured by substituting in water. Separately, the true volume (V1) is measured using an autopicometer AccuPick 1320 manufactured by Shimadzu Corporation. The porosity of the film is assumed to be porosity = (1−V1 / V) × 100.

(4) Flexibility test As shown in FIG. 5, the film was folded at 180 ° and spread so as to sandwich a wire having a diameter of 2 mm. Next, the back side was similarly folded with a wire and the film was expanded. When folding the back, it was folded at the same position as the front. It was visually confirmed whether or not there were cracks in the folds. If there is no crack, it indicates that there is flexibility.

Example 1
56% by weight of calcium carbonate (Vigot 10, manufactured by Shiroishi Calcium Co., Ltd., average particle size 0.1 μm), 32% by weight of polyethylene powder (Hi-Zex Million 340M, manufactured by Mitsui Chemicals, weight average molecular weight 3 million, melting point 136 ° C.) High wax 110P, manufactured by Mitsui Chemicals, weight average molecular weight 1000, melting point 110 ° C.) 12% by weight of mixed polyethylene resin is kneaded using a segment designed biaxial kneader (Plastics Engineering Laboratory). A resin composition was obtained. By rolling this resin composition (roll temperature: 151 ° C.), an original film having a film thickness of about 60 μm was produced.

The obtained raw film was uniaxially stretched about 6.5 times at a stretching temperature of 110 ° C. by a tenter stretching machine to obtain a porous film. The obtained porous film is immersed in an aqueous acid solution (hydrochloric acid concentration 2 mol / L, containing 0.4% by weight of surfactant) to remove calcium carbonate, and a porous film (A) containing no calcium carbonate is obtained. It was.
The obtained porous film (A) had a thickness of 14 μm, a porosity of 48%, and an average pore diameter of 0.1 μm.
Next, a titania sol solution (catalyzed chemical HPW-18NR: TiO2 is 15 nm) and a 4% by weight surfactant aqueous solution (surfactant: Sanyo Kasei Sanmorin 11) were mixed at a weight ratio of 100: 7 to obtain a lipophilic titania sol. A solution was prepared, and this solution was manually bar-coated on a porous film (A) fixed on an aluminum plate. A glass rod was used as the bar, and a spacer was laid so that the liquid film thickness was 50 μm. Thereafter, it was dried at room temperature (25 ° C.) to produce an electrode. When the basis weight of the obtained electrode was measured and the basis weight of the applied titania was determined, it was about 13 g / m ² . Next, in order to measure the density gradient of the semiconductor of this electrode, after embedding the electrode in an epoxy resin, the thickness direction cross section is cut out with a cryomicrotome, and the distribution of titanium element in titania while observing with SEM (electron microscope) Was measured by EPMA (Electron Probe Microanalyzer). The measurement conditions are as follows.
(1) Model EPMA-1610 (manufactured by Shimadzu Corporation)
(2) Acceleration voltage 15 kV
(3) Beam current 30.2 nA
(4) Beam diameter approx. 1μm
(5) Measurement time per point 5 msec.
(6) Detection wavelength 2.7 angstrom (Ti Kα)
4.7 angstrom (Cl Kα)
24 angstrom (O Kα)
(7) Spectroscopic crystal PET (pentaerythritol; Ti, Cl)
LS5A (Cumulative membrane; O)
The obtained EPMA image is shown in FIG. In 61, the area | region 62 is an electrode part of this invention, and the area | region 63 is the epoxy resin used for embedding. That is, the direction 64 is the depth direction of the porous film (A), the 65 side is the coating surface, and the 66 side is the coating back surface. FIG. 6 (68) shows a density distribution chart of the titanium element in the region 67 of the electrode. Corresponding to the EPMA image, the chart 68 is laid out so that the titanium density distribution can be easily understood.
The density gradient of the semiconductor was calculated as follows assuming that it was equal to the density gradient of titanium element.
As can be seen from the chart 68, the titanium element concentration has a maximum value at a depth of 1 μm from the coating surface 65, and then gradually decreases. The reason why the maximum value is not obtained on the surface and the maximum value is obtained at a position slightly deeper than that is because the beam diameter is about 1 μm, and the 100% beam is not used on the outermost surface. Therefore, the maximum value of 1 μm depth is set as the titanium element concentration on the outermost surface of the porous film (A).
On the other hand, the titanium concentration on the back of the coating is set to a value of 1 μm from the surface for the same reason. Since the intensity (count number) of the radiation proportional to the element concentration is 75 on the coated surface and 9.0 on the coated back surface, the ratio is approximately 8: 1. When a flexibility test was performed using the obtained electrode, no cracks were generated.

(Example 2)
Composite element (1) Synthesis of para-aramid solution Poly (paraphenylene terephthalamide) (hereinafter referred to as PPTA) using a 5 liter (l) separable flask having a stirring blade, a thermometer, a nitrogen inlet tube and a powder addition port (Abbreviated) was synthesized. 4200 g of NMP was put into a well-dried flask, and 272.65 g of calcium chloride dried at 200 ° C. for 2 hours was added, and the temperature was raised to 100 ° C. After calcium chloride was completely dissolved, the temperature was returned to room temperature, and 132.91 g of paraphenylenediamine (hereinafter abbreviated as PPD) was added and completely dissolved. While maintaining this solution at 20 ± 2 ° C., 243.32 g of terephthalic acid dichloride (hereinafter abbreviated as TPC) was added in 10 divided portions every about 5 minutes. Thereafter, the solution was kept at 20 ± 2 ° C. for 1 hour, and stirred for 30 minutes under reduced pressure to remove bubbles. The obtained polymerization liquid showed optical anisotropy. A part was sampled, reprecipitated with water and taken out as a polymer, and the intrinsic viscosity of the obtained PPTA was measured and found to be 1.97 dl / g. Next, 100 g of this polymerization solution was weighed into a 500 ml separable flask having a stirring blade, a thermometer, a nitrogen inlet tube and a liquid addition port, and the NMP solution was gradually added. Finally, a PPTA solution having a PPTA concentration of 2.0% by weight was prepared, and this was used as a P solution.

(2) Application of para-aramid solution and preparation of laminated porous film The porous film (A) described in Example 1 was fixed on a glass plate, and P liquid was applied by a bar coater (gap 200 μm) manufactured by Tester Sangyo Co., Ltd. did. Thereafter, PPTA is deposited under the conditions of a humidity of 50% and a temperature of 23 ° C., and then immersed in ion-exchanged water. After 5 minutes, the film-like material is peeled off from the glass plate, and the ion-exchanged water is sufficiently flowed. After washing with water, the membrane was dried while reducing the pressure at 60 ° C. to obtain a laminated porous film. The laminated porous film was a film obtained by laminating a porous film (B) made of PPTA on a porous film (A).
The obtained laminated porous film had a thickness of 18 μm, a porosity of 51%, and an average pore diameter of 0.029 μm.

Next, as in Example 1, titania sol solution (catalyst conversion NR-18: TiO2 is 15 nm) and 4% by weight surfactant aqueous solution (surfactant: Sanyo Kasei Sanmorin 11) are in a weight ratio of 100: 7. To prepare a lipophilic titania sol solution, which was applied to the porous film (A) side of the laminated porous film, and then dried at room temperature (25 ° C.) to produce an electrode. When the basis weight of the obtained composite element was measured and the basis weight of the applied titania was determined, it was about 12 g / m ² .

When the flexibility test of the obtained composite element was performed, no cracks were generated.
Further, SEM observation (10,000 times magnification) was performed on each surface of the obtained composite element, and titania was observed on the porous film (A) surface side, but titania on the porous film (B) surface side. Was not observed.
That is, it was confirmed that the porous film (B) was acting as an insulating layer.

(Comparative Example 1)
The lipophilic titania sol solution described in Example 1 was applied to a commercially available PET film (Toyobo: A4100) and dried at 30 ° C. to obtain an electrode.
When the basis weight of the obtained electrode was measured and the coating basis weight of titania was determined, it was 4 g / m ² .
When the flexibility test of the obtained electrode was performed, many cracks were generated.

It is an example of schematic sectional drawing of the conventional dye-sensitized solar cell. It is an example of schematic sectional drawing of the dye-sensitized solar cell of this invention. 1 is an example of a schematic cross-sectional view of a porous film (A) in which pore inner walls are coated with metal. It is an example of schematic sectional drawing of the dye-sensitized solar cell of this invention. It is the schematic of a flexibility test method. (A) It is the EPMA image of the thickness direction cross section of the electrode obtained in Example 1. FIG. (B) It is a titanium element density chart of the area | region 67 of (a).

Explanation of symbols

11 .. Transparent substrate 12 .. Collecting electrode 13 ... Semiconductor electrode layer 14 ... Electrolyte solution
15 .. Conductive film
16. · Substrate 17 ·· Sensitizing dye 21 ·· Transparent substrate 22 ·· Current collecting electrode 23 ·· Porous electrode 231 ·· Conductive substance 232 ·· Porous film (A)
24..Electrolyte solution
25 .. Counter electrode 26.. Substrate 27. Sensitizing dye 34. Metal coating 43. Composite element 432 Porous film (B)
51..Electrode or composite element 52..Wire (diameter 2 mm)
61..EPMA image 62..Electrode part 63..Epoxy resin 64 used for embedding..Depth direction 65..Coating surface 66..Coating back surface 67..Titanium element analysis area 68..Titanium Density distribution chart

Claims (22)

Selected from the group consisting of a conductor and a semiconductor in the through hole of the porous film (A) having a through hole, an average pore diameter d1 of 0.02 to 3 μm, and a porosity of 40 to 90% A porous electrode filled with a conductive material. The porous electrode according to claim 1, wherein the porous film (A) has an average pore diameter d1 of 0.04 to 1 μm. The porous electrode according to claim 1 or 2, wherein the conductive material is filled in a density gradient in the thickness direction of the porous film (A). The porous electrode according to claim 3, wherein the ratio of the density of the conductive material on one surface of the porous film (A) to the density of the conductive material on the other surface is 2 or more. The porous electrode according to any one of claims 1 to 4, wherein the inner wall of the through hole of the porous film (A) is coated with a metal. The porous electrode according to claim 1, wherein the conductive substance is a semiconductor. The porous electrode according to claim 1, wherein the conductive substance is titanium oxide. The porous electrode according to any one of claims 1 to 7, wherein a sensitizing dye is supported on the surface of the conductive substance. The porous electrode according to claim 1, wherein the conductive substance is a conductor. The porous electrode according to claim 9, wherein the conductive substance is a carbonaceous powder. Selected from the group consisting of a conductor and a semiconductor in the through hole of the porous film (A) having a through hole, an average pore diameter d1 of 0.02 to 3 μm, and a porosity of 40 to 90% Composite element in which a porous film (B) having a through hole whose average pore diameter is smaller than the average pore diameter d1 of the porous film (A) is laminated on one surface of a porous electrode filled with a conductive material . Composite element according to claim 11, the porous film conductive material in the through hole of the (B) is equal to or unfilled. A first electrode and a second substrate facing each other, and a counter electrode, a porous electrode and a collector electrode arranged between the two substrates in order from the first substrate, and the counter electrode and the collector electrode A dye-sensitized solar cell having an electrolyte disposed therebetween with a porous electrode, the porous electrode having through holes, an average pore diameter d1 of 0.02 to 3 μm, and pores The electrode is filled with a semiconductor in the through-hole of the porous film (A) having a rate of 40 to 90%, the second substrate is a transparent substrate, and the semiconductor and the counter electrode are in contact with each other. A dye-sensitized solar cell, wherein a sensitizing dye is supported on the surface of the semiconductor. The dye-sensitized solar cell according to claim 13, wherein the through-hole of the porous film (A) is further filled with a conductor. Between the porous electrode and the counter electrode, a porous film (B) having through-holes laminated on the surface of the porous electrode and having an average pore diameter smaller than the average pore diameter d1 of the porous film (A) Is arranged, The dye-sensitized solar cell of Claim 13 or 14 characterized by the above-mentioned. The dye-sensitized solar cell according to claim 15, the porous film (B) conductive material in the through hole of the characterized in that the unfilled. A first electrode and a second substrate facing each other, and a counter electrode, a porous electrode and a collector electrode arranged between the two substrates in order from the first substrate, and the counter electrode and the collector electrode An electric double layer capacitor having an electrolyte disposed therebetween via the porous electrode, the porous electrode having through holes, an average pore diameter d1 of 0.02 to 3 μm, and pores An electrode in which a through-hole of the porous film (A) having a rate of 40 to 90% is filled with a conductor, and the conductor and the counter electrode are not in contact with each other. Multilayer capacitor. Between the porous electrode and the counter electrode, a porous film (B) having through-holes laminated on the surface of the porous electrode and having an average pore diameter smaller than the average pore diameter d1 of the porous film (A) The electric double layer capacitor according to claim 17, wherein: Electric double layer capacitor of claim 18, the porous film (B) conductive material in the through hole of the characterized in that the unfilled. The electric double layer capacitor according to claim 17, wherein the conductor is a carbonaceous powder. Conductivity selected from the group consisting of a conductor and a semiconductor on the surface of the porous film (A) having through holes, an average pore diameter d1 of 0.02 to 3 μm, and a porosity of 40 to 90%. A method for producing a porous electrode, comprising a step of applying a liquid containing a conductive substance and filling the through hole of the porous film (A) with the conductive substance. Selected from the group consisting of a conductor and a semiconductor in the through hole of the porous film (A) having a through hole, an average pore diameter d1 of 0.02 to 3 μm, and a porosity of 40 to 90% Forming a polymer solution layer by applying a polymer solution containing a polymer and a solvent to one side of a porous electrode filled with a conductive material, and a solvent from the polymer solution layer The manufacturing method of the composite element which has the process of removing and forming the porous film (B) which has a through-hole whose average hole diameter is smaller than the average hole diameter d1 of a porous film (A).

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