JP2006282970A - Laminated film for dye-sensitized solar cell and electrode for the dye-sensitized solar cell using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated polyester film excellent in close adhesiveness of a transparent electroconductive layer with a porous semiconductor layer and by using which a dye-sensitized solar cell having high power generation with durability can be prepared, and provide electrodes. <P>SOLUTION: The laminated film for the dye-sensitized solar cell comprises the polyester film having ≤5% light transmission at 380 nm wavelength, ≤50% light transmission at 400 nm and ≥70% light transmission at 420 nm and the transparent electroconductive layer having ≥40mN/m surface tension and installed to the one face of the polyester film. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a dye-sensitized solar cell laminated film and a dye-sensitized solar cell electrode.

  The dye-sensitized solar cell has been proposed since a photoelectric conversion element using dye-sensitized semiconductor fine particles was proposed ["Nature", Vol. 353, pages 737-740 (1991)]. It is attracting attention as a new solar battery that replaces batteries. In particular, dye-sensitized solar cells using a plastic film as a support can be made flexible and lightweight, and many studies have been made.

  However, when a plastic film is used as a support, it is difficult to process the porous semiconductor layer on the transparent conductive layer, and it is difficult to ensure adhesion between the transparent conductive layer and the porous semiconductor. There are many problems compared to the case of using as

  Among plastic films, a polyester film is a material useful as a support for a dye-sensitized solar cell because it is inexpensive but highly transparent and has heat resistance. However, if the surface characteristics of the transparent conductive layer on the polyester film are not appropriate, it is very difficult to ensure the adhesion between the transparent conductive layer and the porous semiconductor layer, and there is a problem that the photovoltaic performance is lowered.

  In addition, in a dye-sensitized solar cell, a metal oxide semiconductor that is activated by light (especially ultraviolet rays) is used as an electrode material, so that the dye adsorbed as a photosensitizer deteriorates and the photovoltaic efficiency is improved. There is a problem of gradual decline.

  On the other hand, Japanese Patent Application Laid-Open No. 2003-217690 proposes a method of providing a resin layer containing an ultraviolet absorber by coating. However, it is difficult to shield 400 nm, which is the excitation wavelength of titanium oxide, which is a metal oxide semiconductor widely used in dye-sensitized solar cells. Therefore, to obtain a sufficient ultraviolet shielding effect by these ultraviolet absorbers, it is necessary to increase the thickness of the resin layer, which is technically difficult and uneconomical. Further, in the case of these ultraviolet absorbers, when the absorption wavelength is widely applied to visible light, there is a problem that the photovoltaic efficiency is lowered.

JP-A-11-288745 JP 2001-160426 A JP 2002-50413 A

  The present invention solves the problems of the prior art, improves the workability and adhesion of the porous semiconductor layer, and suppresses deterioration of the dye due to photoexcitation of the metal oxide semiconductor even when exposed to sunlight for a long time. It is an object of the present invention to provide a laminated film for a dye-sensitized solar cell that can maintain high photovoltaic power generation efficiency.

  That is, an object of the present invention is to provide a dye-sensitized solar cell that is excellent in adhesion between the transparent conductive layer and the porous semiconductor layer, and that can produce a dye-sensitized solar cell having high photovoltaic power generation performance while having durability. It is providing the laminated film for dyes, and the electrode for dye-sensitized solar cells.

  That is, the present invention was provided on a polyester film having a light transmittance at a wavelength of 380 nm of 5% or less, a light transmittance at 400 nm of 50% or less and a light transmittance at 420 nm of 70% or more, and one surface thereof. A laminated film for a dye-sensitized solar cell, comprising a transparent conductive layer having a surface tension of 40 mN / m or more.

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in the adhesiveness of a transparent conductive layer and a porous semiconductor layer, and can produce a dye-sensitized solar cell with high photovoltaic power generation performance while having durability. A laminated film and an electrode for a dye-sensitized solar cell can be provided.

Hereinafter, the present invention will be described in detail.
[Polyester film]
The polyester film in the present invention has a light transmittance at a wavelength of 380 nm of 5% or less, a light transmittance at 400 nm of 50% or less, and a light transmittance at 420 nm of 70% or more. When the light transmittance at a wavelength of 380 nm exceeds 5% or the light transmittance at 400 nm exceeds 50%, when a dye-sensitized solar cell is prepared, the metal oxide semiconductor such as titanium oxide contained therein is excited by light. The dye adsorbed on the surface of the metal oxide semiconductor is deteriorated. If the light transmittance at 420 nm is less than 70%, the amount of transmitted light is reduced and the photovoltaic power generation efficiency is lowered.

[polyester]
In the present invention, the polyester constituting the polyester film is a linear saturated polyester synthesized from an aromatic dibasic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof.

  Specific examples of such polyesters include polyethylene terephthalate, polyethylene isophthalate, polyethylene isophthalate, polybutylene terephthalate, poly (1,4-cyclohexylenedimethylene terephthalate), polyethylene-2,6-naphthalate, and the like. It may be a blend of these copolymers or a small proportion of other resins. Among these polyesters, polyethylene terephthalate and polyethylene-2,6-naphthalate are preferable because of a good balance between mechanical properties and optical properties.

  The polyester may be a homopolymer or a copolymer obtained by copolymerizing the third component, but a homopolymer is preferred. When the polyester is polyethylene terephthalate, isophthalic acid copolymerized polyethylene terephthalate is optimal as the copolymer. The isophthalic acid copolymerized polyethylene terephthalate preferably contains 5 mol% or less of isophthalic acid. The polyester may be copolymerized with a copolymer component or copolymer alcohol component other than isophthalic acid in a range that does not impair the properties thereof, for example, in a proportion of 3 mol% or less with respect to the total acid component or the total alcohol component. . Examples of the copolymer acid component include aromatic dicarboxylic acids such as phthalic acid and 2,6-naphthalenedicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, and 1,10-decanedicarboxylic acid. Examples of the alcohol component include aliphatic diols such as 1,4-butanediol, 1,6-hexanediol and neopentyl glycol, and alicyclic diols such as 1,4-cyclohexanedimethanol. it can. These can be used alone or in combination of two or more.

  When the polyester is polyethylene-2,6-naphthalenedicarboxylate, naphthalenedicarboxylic acid is used as the main dicarboxylic acid component, and ethylene glycol is used as the main glycol component. Examples of naphthalenedicarboxylic acid include 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, and 1,5-naphthalenedicarboxylic acid. Among these, 2,6-naphthalenedicarboxylic acid is preferable. Here, “main” means at least 90 mol%, preferably at least 95 mol% of all repeating units in the constituent components of the polymer that is a component of the film of the present invention.

  In the case of a copolymer, a compound having two ester-forming functional groups in the molecule can be used as a copolymer component constituting the copolymer. Examples of such a compound include oxalic acid, adipic acid, phthalic acid, and sebacic acid. , Dodecanedicarboxylic acid, isophthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, phenylindanedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, tetralindicarboxylic acid, decalindicarboxylic acid, diphenylether Dicarboxylic acids such as dicarboxylic acids, oxycarboxylic acids such as p-oxybenzoic acid and p-oxyethoxybenzoic acid, or propylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, cyclohexane Glycol, neopentyl glycol, ethylene oxide adduct of bisphenol sulfone, ethylene oxide adduct of bisphenol A, diethylene glycol, can be preferably used dihydric alcohols such as polyethylene glycol.

  These compounds may be used alone or in combination of two or more. Among these, preferably the acid component is isophthalic acid, terephthalic acid, 4,4′-diphenyldicarboxylic acid, 2,7-naphthalenedicarboxylic acid, p-oxybenzoic acid, and the glycol component is trimethylene glycol, It is an ethylene oxide adduct of cyclohexane dimethylene glycol, neopentyl glycol and bisphenol sulfone.

  The polyethylene-2,6-naphthalenedicarboxylate may be one in which a terminal hydroxyl group and / or a carboxyl group is partially or entirely blocked with a monofunctional compound such as benzoic acid or methoxypolyalkylene glycol. Further, it may be one obtained by copolymerizing a very small amount of an ester-forming compound such as trimellitic acid, glycerin, pentaerythritol and the like within a range in which a substantially linear polymer is obtained.

  The polyester in the present invention is a conventionally known method, for example, a method of directly obtaining a low polymerization degree polyester by reaction of dicarboxylic acid and glycol, or a lower alkyl ester of dicarboxylic acid and glycol are conventionally known transesterification catalysts, such as sodium It can be obtained by performing a polymerization reaction in the presence of a polymerization catalyst after reacting with one or more of compounds containing potassium, magnesium, calcium, zinc, strontium, titanium, zirconium, manganese, and cobalt. it can. Polymerization catalysts include antimony compounds such as antimony trioxide and antimony pentoxide, germanium compounds represented by germanium dioxide, tetraethyl titanate, tetrapropyl titanate, tetraphenyl titanate or partial hydrolysates thereof, and titanyl ammonium oxalate. , Titanium compounds such as potassium titanyl oxalate and titanium trisacetylacetonate can be used.

  When polymerization is performed via a transesterification reaction, a phosphorus compound such as trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, or normal phosphoric acid is usually added for the purpose of deactivating the transesterification catalyst before the polymerization reaction. However, the content of polyethylene-2,6-naphthalenedicarboxylate as the phosphorus element is preferably 20 to 100 ppm from the viewpoint of thermal stability of the polyester.

  The polyester may be converted into chips after melt polymerization, and further subjected to solid phase polymerization under heating under reduced pressure or in an inert gas stream such as nitrogen.

  In the present invention, the polyester is preferably a polyester containing 90 mol% or more, preferably 95% or more, more preferably 97% or more of ethylene terephthalate units or ethylene-2,6-carboxylate units. This polyester is preferable because it has a high aromatic ring content and sufficient heat resistance.

  The intrinsic viscosity of the polyester is preferably 0.40 dl / g or more, more preferably 0.40 to 0.90 dl / g. If the intrinsic viscosity is less than 0.40 dl / g, process cutting may occur frequently, which is not preferable. If it exceeds 0.9 dl / g, the melt viscosity is high and melt extrusion becomes difficult, and the polymerization time is long and uneconomical.

  It is preferable that the polyester film in the present invention contains substantially no particles. If the particles are contained, high transparency is impaired, or the surface becomes rough and processing of the transparent conductive layer becomes difficult, which is not preferable.

[Ultraviolet absorber]
In the present invention, it is important that the polyester constituting the polyester film has a light transmittance at a wavelength of 380 nm of 5% or less, a light transmittance at 400 nm of 50% or less, and a light transmittance at 420 nm of 70% or more. It is.

  The polyester film of the present invention having this light transmittance preferably contains 0.05 to 30% by weight, more preferably 0.08 to 20% by weight of an ultraviolet absorber in the polyester described later, thereby forming a film. Obtainable. When the blending amount of the ultraviolet absorber is within this range, it is preferable because the ultraviolet absorbing effect can be exhibited and uniformly dispersed.

で表わされる環状イミノエステル及び下記式（ＩＩ）

（ここで、Ａは下記式（ＩＩ）−ａ

で表わされる基であるか又は
下記式（ＩＩ）−ｂ

で表わされる基であり；Ｒ_１およびＲ_２は同一もしくは異なる１価の炭化水素残基であり、Ｘ_３はナフタレン環残基である。） As the ultraviolet absorber, it is preferable to use at least one compound selected from cyclic imino esters represented by the following formulas (I) and (II).

And a cyclic imino ester represented by the following formula (II)

(Where A is the following formula (II) -a

Or a group represented by the following formula (II) -b

R ₁ and R ₂ are the same or different monovalent hydrocarbon residues, and X ₃ is a naphthalene ring residue. )

In the formula (I), X ₁ is a divalent aromatic residue in which the two bonds from X ₁ represented by the above formula are in the 1-position and 2-position positional relationship. Examples of the binding site when X ₁ is a naphthalene residue include the 1,2-position and the 2-, 3-position, but the 2-position is more preferred. X ₁ may be partially substituted. Examples of the substituent include alkyl having 1 to 10 carbon atoms such as methyl, ethyl, propyl, hexyl and decyl; aryl having 6 to 12 carbon atoms such as phenyl; cycloalkyl having 5 to 12 carbon atoms such as cyclopentyl and cyclohexyl; Aralkyl having 8 to 20 carbon atoms such as phenylethyl; alkoxy having 1 to 10 carbon atoms such as methoxy, ethoxy, decyloxy and the like; nitro; ester; amide; imide; halogen such as chlorine and bromine; Proponyl, zenzoyl, decanoyl and the like.

X ₂ is a 1, 2 or trivalent aromatic residue. X ₂ is monovalent when n = 1, and similarly bivalent when n = 2 and trivalent when n = 3. When X ₂ is a naphthalene residue and n = 1, the binding site may be the 1-position or 2-position. More preferred is the second position. When X ₂ is a naphthalene residue and n = 2, the binding sites are 1, 2, 1, 3, 1, 4, 1, 5, 1, 6, 6, 1, 7, 8th, 2, 3rd, 2, 6th, 2nd and 7th are listed. More preferably, they are the 1,3-position, 1,4-position, 1,5-position, 1,6-position, 2,6-position, and 2,7-position where the bonding groups are separated from each other. More preferably, it is the 2nd and 6th positions. When X2 is a naphthalene residue and n = 3, 1, 2, 3 position, 1, 2, 4 position, 1, 2, 5 position, 1, 2, 6 position, 1, 2, 7 position, 1, 2,8, 2,3,5, 2,3,6, 1,3,5, 1,3,6, 1,3,7, 1,3,8, 1,4 , 5th, 1, 4th, 6th. More preferred are 1,3,5, 1,3,6, 1,3,7, 1,4,6, which are separated from each other.

X ₂ may be partially substituted. Examples of the substituent include alkyl having 1 to 10 carbon atoms such as methyl, ethyl, propyl, hexyl and decyl; aryl having 6 to 12 carbon atoms such as phenyl; cycloalkyl having 5 to 12 carbon atoms such as cyclopentyl and cyclohexyl; Aralkyl having 8 to 20 carbon atoms such as phenylethyl; alkoxy having 1 to 10 carbon atoms such as methoxy, ethoxy and decyloxy; nitro; halogen such as chlorine and bromine; acyl having 2 to 10 carbon atoms such as acetyl, proponyl, zenzoyl and decanoyl And so on. Examples of the formula (I) include the following compounds.

ここで芳香族環の一部が置換されていても良い。置換基としては前記置換基が挙げられる。 When n = 1

Here, a part of the aromatic ring may be substituted. Examples of the substituent include the above substituents.

ここで芳香族環の一部が置換されていても良い。置換基としては前記置換基が挙げられる。 When n = 2

Here, a part of the aromatic ring may be substituted. Examples of the substituent include the above substituents.

ここで芳香族環の一部が置換されていても良い。置換基としては前記置換基が挙げられる。 When n = 3

Here, a part of the aromatic ring may be substituted. Examples of the substituent include the above substituents.

In the formula (II), X ₃ is a tetravalent naphthalene ring. The binding sites for cyclic iminoester and A are 1,2- and 3,4-positions, 1,2- and 5,6-positions, 1,2- and 6,7-positions, 1,2- and 7,8-positions. 2,3 and 5,6, 2,3,6,7. More preferably, they are the 1st, 2nd and 5th, 6th, 1st, 2nd and 6th, 7th, 2nd, 3rd and 6th, 7th positions. X ₃ may be partially substituted. Examples of the substituent include alkyl having 1 to 10 carbon atoms such as methyl, ethyl, propyl, hexyl and decyl; aryl having 6 to 12 carbon atoms such as phenyl; cycloalkyl having 5 to 12 carbon atoms such as cyclopentyl and cyclohexyl; Aralkyl having 8 to 20 carbon atoms such as phenylethyl; alkoxy having 1 to 10 carbon atoms such as methoxy, ethoxy and decyloxy; nitro; halogen such as chlorine and bromine; acyl having 2 to 10 carbon atoms such as acetyl, proponyl, zenzoyl and decanoyl And so on.

R ₁ and R ₂ may be a monovalent hydrocarbon group. For example, alkyl having 1 to 10 carbon atoms such as methyl, ethyl, propyl, hexyl, decyl, etc .; aryl having 6 to 12 carbon atoms such as phenyl; cycloalkyl having 5 to 12 carbon atoms such as cyclopentyl, cyclohexyl and the like; Aralkyl such as phenylethyl, etc .; alkoxy having 1 to 10 carbon atoms such as methoxy, ethoxy, decyloxy, etc .; ester; amide; imide; nitro; halogen such as chlorine, bromine and the like; acyl having 2 to 10 carbon atoms such as acetyl, proponyl, zenzoyl , Decanoyl, etc .; phenyl, naphthyl group and the like.

ここで芳香族環の一部が置換されていても良い。置換基としては前記置換基が挙げられる。 Examples of the compound (I) include the following compounds.

Here, a part of the aromatic ring may be substituted. Examples of the substituent include the above substituents.

  The addition of the ultraviolet absorber to the polyester can be carried out, for example, by a method such as a polyester polymerization step, kneading into a polymer in a melting step before film formation, or impregnation into a biaxially stretched film. In particular, kneading into the polymer in the melting step before film formation is also preferred in order to prevent a decrease in the degree of polymerization of the polyester. At that time, the kneading of the ultraviolet absorber can be performed by a direct addition method of a compound powder, a master batch method or the like.

  In the polyester film of the present invention, the absolute value of the difference in heat shrinkage between the longitudinal direction and the width direction of the film when treated at 200 ° C. for 10 minutes is preferably 0.8% or less, more preferably 0.5% or less, Particularly preferably, it is 0.3% or less. If the absolute value of the difference in thermal shrinkage exceeds 0.8%, the adhesion between the transparent conductive layer of the laminated film and the porous semiconductor deteriorates, and sufficient photovoltaic performance is obtained when a dye-sensitized solar cell is produced. It is not preferable because it disappears. In addition, the thermal contraction rate in the longitudinal direction of the film is preferably 0 to 0.5%, more preferably 0 to 0.3%. If it exceeds 0.5%, a dimensional change occurs at the time of final cell assembly, which is not preferable.

[Film properties]
In order to perform photovoltaic power generation more efficiently, the polyester film in the present invention preferably has a haze value of 1.5% or less, more preferably 1.0% or less, and particularly preferably 0.5% or less. Within this range, efficient photovoltaic power generation can be performed.

  In order to facilitate the processing of the transparent conductive layer, the polyester film in the present invention has a surface three-dimensional centerline average roughness of preferably 0.0001 to 0.02 μm on both sides, more preferably 0.0001 to 0. .015 μm, particularly preferably 0.0001 to 0.010 μm. And the three-dimensional centerline average roughness of at least one side is preferably 0.0001 to 0.005 μm, more preferably 0.0005 to 0.004 μm. This range is preferable because the transparent conductive layer can be easily processed.

  The thickness of the polyester film in the present invention is preferably 10 to 500 μm, more preferably 20 to 400 μm, and particularly preferably 50 to 300 μm. This range is preferable because the transparent conductive layer can be easily processed.

[Production method of polyester film]
Next, the preferable manufacturing method of the polyester film in this invention is demonstrated. The glass transition temperature is abbreviated as Tg.

  In the polyester film of the present invention, the polyester is melt-extruded into a film shape, cooled and solidified with a casting drum to form an unstretched film, and this unstretched film is Tg to (Tg + 60) ° C. once or twice or more in the longitudinal direction. The film is stretched so that the magnification is 3 to 6 times, and then stretched so that the magnification is 3 to 5 times in the width direction at Tg to (Tg + 60) ° C., and further 1 to 1 at Tm 180 ° C. to 255 ° C. if necessary. It can be obtained by performing a heat treatment for 60 seconds. In order to reduce the difference in thermal shrinkage between the longitudinal direction and the width direction of the polyester film and the thermal shrinkage in the longitudinal direction, a method of shrinking in the longitudinal direction in a heat treatment step as disclosed in JP-A-57-57628 Alternatively, a method of relaxing heat treatment of a film in a suspended state as disclosed in JP-A-1-275031 can be used.

[Transparent conductive layer]
In the present invention, the transparent conductive layer formed on the polyester film is usually a conductive metal oxide (fluorine-doped tin oxide, indium-tin composite oxide (ITO), metal thin film (for example, platinum, gold, Silver, copper, aluminum, etc.) and carbon materials can be used.This conductive layer may be a laminate or composite of two or more types, among which ITO has high light transmittance and low resistance. The surface resistance of the transparent conductive layer is preferably 100 Ω / □ or less, more preferably 40 Ω / □ or less, and if it exceeds 100 Ω / □, the generated photocurrent cannot sufficiently flow, which is not preferable. .

  The thickness of the transparent conductive layer is preferably 100 to 500 nm. If it is thinner than this, the surface resistance value cannot be lowered sufficiently, and if it is thicker, the light transmittance is lowered and the transparent conductive layer is easily broken, which is not preferable.

  The surface tension of the transparent conductive layer in the present invention is 40 mN / m or more, preferably 65 mN / m or more. When the surface tension is less than 40 mN / m, the adhesion between the transparent conductive layer and the porous semiconductor is poor. When the surface tension is 65 mN / m or more, it is preferable because the porous semiconductor layer can be easily formed by application of an aqueous coating liquid in which the main component of the solvent is water. The practical upper limit of the surface tension of the transparent conductive layer is about 75 mN / m, which makes it easy to apply a complete aqueous coating material.

  As means for achieving the above surface tension, for example, (1) a method of activating the surface of a transparent conductive thin film with an acidic or alkaline solution, (2) activation by irradiating the surface of the thin film with ultraviolet rays or electron beams And (3) a method of activating by applying corona treatment or plasma treatment. Among these, the method of activating the surface by plasma treatment is particularly preferable because high surface tension can be obtained.

[Easily adhesive layer]
Moreover, in order to improve the adhesiveness of a polyester film and a transparent conductive layer, it is preferable to provide an easily bonding layer between a polyester film and a transparent conductive layer. The thickness of the easy adhesion layer is preferably 10 to 200 nm, more preferably 20 to 150 nm. If the thickness of the easy-adhesion layer is less than 10 nm, the effect of improving the adhesion is poor, and if it exceeds 200 nm, cohesive failure of the easy-adhesion layer tends to occur and the adhesion may be lowered.

  As a method of providing the easy-adhesion layer, a method of applying by coating in the production process of the polyester film is preferable, and it is preferable to apply to the polyester film before the orientation crystallization is completed. Here, the polyester film before the crystal orientation is completed is an unstretched film, a uniaxially oriented film in which the unstretched film is oriented in either the longitudinal direction or the transverse direction, and further in two directions, the longitudinal direction and the transverse direction. And the like that have been oriented at a low magnification (biaxially stretched film before being finally re-stretched in the machine direction or the transverse direction to complete orientation crystallization). In particular, it is preferable to apply the aqueous coating liquid of the above composition to an unstretched film or a uniaxially stretched film oriented in one direction, and perform longitudinal stretching and / or lateral stretching and heat setting as it is.

  As a constituent material of the easy-adhesion layer, it is preferable to use a resin that exhibits excellent adhesion to both the polyester film and the transparent conductive layer. Specific examples include polyester resins, acrylic resins, urethane acrylic resins, silicon acrylic resins, melamine resins, and polysiloxane resins. These resins can be used alone or as a mixture of two or more.

[Hard coat]
Furthermore, a hard coat layer may be provided between the easy-adhesion layer and the transparent conductive layer in order to improve the adhesion between the polyester film and the transparent conductive layer, particularly the durability of the adhesion. The hard coat layer is preferably a method in which a hard coat constituent coating liquid is applied onto a polyester film provided with an easy-adhesion layer. The hard coat layer may be composed of any material that exhibits excellent adhesion to both the easy-contact layer and the transparent conductive layer, such as an acrylic resin, a urethane resin, a silicon resin, a UV curable resin, and an epoxy resin. Examples thereof include a resin component such as a resin and a mixture of these with inorganic particles such as alumina, silica and mica. The thickness of the hard coat layer is preferably 0.01 to 20 μm, more preferably 1 to 10 μm. If it is less than 0.01 μm, it is not preferable because the durability of adhesion is not sufficiently improved, and if it exceeds 20 μm, the light transmittance may decrease particularly when fine particles are added, which is not preferable.

[Antireflection layer]
In the laminated film of the present invention, an antireflection layer is preferably provided on the surface opposite to the transparent conductive layer for the purpose of increasing the light transmittance and increasing the photovoltaic power generation efficiency. For the antireflection layer, a method in which a material having a refractive index different from that of the polyester film is formed in a single layer or two or more layers is preferably employed. In the case of a single layer structure, it is better to use a material having a refractive index smaller than that of the base film, and in the case of a multilayer structure of two or more layers, the layer adjacent to the laminated film is larger than the polyester film. It is preferable to select a material having a refractive index smaller than that of a material having a high refractive index and a layer laminated thereon.

As a material constituting such an antireflection treatment layer, any material that satisfies the above-described refractive index relationship may be used regardless of whether it is an organic material or an inorganic material. Preferred examples include CaF ₂ , Mg ₂ , Examples of the dielectric include NaAlF ₄ , SiO ₂ , ThF ₄ , ZrO ₂ , Nd ₂ O ₃ , SnO ₂ , TiO ₂ , CeO ₂ , ZnS, and In ₂ O ₃ .

  The method for laminating the antireflection treatment layer may be a dry coating method such as a vacuum deposition method, a sputtering method, a CVD method, or an ion plating method, or a wet coating method such as a gravure method, a reverse method, or a die method. Furthermore, prior to the lamination of the antireflection treatment layer, a known pretreatment such as a corona discharge treatment, a plasma treatment, a sputter etching treatment, an electron beam irradiation treatment, an ultraviolet ray irradiation treatment, a primer treatment, and an easy adhesion treatment may be performed.

[electrode]
The dye-sensitized solar cell electrode in the present invention is formed by laminating a porous semiconductor layer on a transparent conductive layer. The semiconductor material constituting the porous semiconductor layer is an n-type semiconductor such as titanium oxide (TiO ₂ ), zinc oxide (ZnO), or tin oxide (SnO ₂ ), and a semiconductor in which a plurality of these semiconductors are combined. Materials can also be used.

  The porous semiconductor layer has a structure in which ultrafine particles of semiconductor are sintered or fused, and the particle size thereof is preferably 5 to 100 nm, more preferably 5 to 50 nm in terms of the average particle size of primary particles. If it is less than 5 nm, the primary particle interface is not preferred because the movement of electrons is hindered, and if it exceeds 100 nm, the specific surface area of the particles is reduced and the amount of adsorbed dye is reduced.

  Two or more kinds of fine particles having different particle size distributions may be mixed, and semiconductor particles having a large particle size, for example, about 300 nm may be mixed for the purpose of scattering incident light and improving the light capture rate.

  Ultrafine particles constituting the porous semiconductor layer may be, for example, a known sol-gel method or gas phase pyrolysis method (published by Technical Education Publishing Co., 2001, supervised by Shozo Yanagida, “Basics and Applications of Dye-sensitized Solar Cells” or 1995. (See “Thin-film coating technology by sol-gel method” published by Japan Technical Information Association).

  The method for forming the porous semiconductor layer is not particularly limited, but for example, a coating method, that is, a dispersion containing the porous semiconductor is applied onto the transparent conductive layer of the laminated film and dried by heating to support the porous layer. Preferably it is immobilized on top. At this time, in order to adjust the dispersion of semiconductor fine particles, in addition to the sol-gel method described above, a method of precipitating fine particles in a solvent as a coprecipitation product of a chemical reaction, A method of pulverizing and dispersing can be used.

  As a dispersion medium, water or various organic solvents are used. When dispersing, for example, a polymer such as polyethylene glycol, hydroxyethyl cellulose, carboxymethyl cellulose, a surfactant, an acid or a chelating agent is used as a dispersion aid. Add a small amount, apply onto a support, and form a film. This coating should be performed using any method conventionally used for coating processing, such as roller method, dipping method, air knife method, blade method, wire bar method, slide hopper method, extrusion method, curtain method, etc. Can do. Further, a spin method or a spray method using a general-purpose machine can also be used. Application may be made using wet printing such as intaglio, rubber plate, screen printing, as well as the three major printing methods of letterpress, offset and gravure. From these, a preferred film forming method is selected according to the liquid viscosity and the wet thickness.

  150 to 250 ° C., preferably 170 to 230 ° C., more preferably 180 to 230 ° C. in order to reinforce the electronic contact between the semiconductor fine particles and improve the adhesion to the support with respect to the coated layer of semiconductor fine particles. Heat treatment is preferably performed at 220 ° C. By performing the heat treatment at 150 to 250 ° C., the resistance increase of the porous semiconductor layer can be reduced while preventing deformation of the polyester film support due to heating. Furthermore, the semiconductor fine particles may be irradiated with ultraviolet light that is strongly absorbed by the fine particles, or the fine particle layer may be heated by irradiating the microwaves to enhance the physical bonding between the fine particles. it can.

  For forming the porous semiconductor layer, a method of supporting a thin film of particles by electrodeposition can also be used. That is, the semiconductor fine particles are added to an appropriate low-conductivity solvent such as pure water, polar organic solvents such as alcohol, acetonitrile and THF, nonpolar organic solvents such as hexane and chloroform, or a mixed solvent thereof, so that there is no aggregation. The conductive resin sheet electrode to be electrodeposited and the counter electrode are made to face each other in parallel at a constant interval, the dispersion liquid is injected into the gap, and a DC voltage is applied between the electrodes. In this way, by selecting the concentration of the dispersion and the electrode interval, a porous semiconductor layer, which is an electrodeposition film having a constant and uniform thickness, is formed on the substrate electrode.

The thickness of the porous semiconductor layer is preferably 1 to 30 μm, more preferably 2 to 10 μm. High transparency can be obtained in this range. The coating amount of the coating liquid is preferably 0.5 to 5 to 20 g / m ² , particularly preferably 5 to 10 g / m ² per 1 m ² of the semiconductor fine particle support. If it is less than 0.5 g, the amount of dye adsorbed is small, which is not preferable, and if it exceeds 20 g, the semiconductor layer tends to be brittle.

For the purpose of preventing the transparent conductive layer carrying the porous semiconductor from being electrically short-circuited with the counter electrode, an undercoat layer may be provided on the transparent conductive layer in advance. As the undercoat layer, TiO ₂ , SnO ₂ , ZnO, Nb ₂ O ₅ , particularly TiO ₂ is preferable. This undercoat layer can be provided by, for example, a sputtering method in addition to the spray pyrolysis method described in Electrochim, Acta 40, 643 to 652 (1995). The thickness of the undercoat layer is preferably 5 to 1000 nm, particularly preferably 10 to 500 nm. If the thickness is less than 5 nm, the target short-circuit prevention performance is insufficient because it is insufficient, and if it exceeds 1000 nm, the thickness of the entire layer tends to be too thick and becomes brittle.

[Preparation of dye-sensitized solar cell]
In order to produce a dye-sensitized solar cell using the electrode of the present invention, a known method can be used.
(1) A dye is adsorbed on the porous semiconductor layer of the electrode of the present invention. It has the property of absorbing light in the visible and infrared regions, such as organometallic complex dyes represented by ruthenium bipyridine complexes (ruthenium complexes), cyanine dyes, coumarin dyes, xanthene dyes, porphyrin dyes, etc. A dye solution is prepared by dissolving a dye in a solvent such as alcohol or toluene, and the porous semiconductor layer is immersed, or sprayed or applied to the porous semiconductor layer. (Electrode A)
(2) As the counter electrode, a thin platinum layer formed by sputtering on the transparent conductive layer side of the laminated film of the present invention is used. (Electrode B)
(3) The electrode A and the electrode B are overlapped by inserting a thermocompression-bondable polyethylene film frame spacer (thickness 20 μm), the spacer portion is heated to 120 ° C., and both electrodes are pressure-bonded. Further, the edge portion is sealed with an epoxy resin adhesive.
(4) An electrolyte aqueous solution containing lithium iodide and iodine (molar ratio 3: 2) and 3% by weight of nylon beads having an average particle diameter of 20 μm as spacers is passed through a small hole for injecting electrolyte provided in advance in the corner of the sheet. inject. Thoroughly deaerate the inside and finally seal the small holes with an epoxy resin adhesive.

Next, the present invention will be described in more detail with reference to examples.
In addition, each characteristic value in an example was measured with the following method.
(1) Intrinsic viscosity Intrinsic viscosity ([η] dl / g) was measured with an o-chlorophenol solution at 35 ° C.

(2) Film thickness Using a micrometer (K-402B type manufactured by Anritsu Co., Ltd.), measurement is performed at 10 cm intervals in the continuous film forming direction and the width direction of the film, and a total of 300 film thicknesses are measured. did. The average value of the film thicknesses of the obtained 300 locations was calculated and used as the film thickness.

(3) Light transmittance The light transmittance at wavelengths of 370 nm and 400 nm was measured using a spectrophotometer MPC3100 manufactured by Shimadzu Corporation.

(4) Haze value In accordance with JIS K6714-1958, the total light transmittance Tt (%) and the scattered light transmittance Td (%) were measured using a haze measuring device (NDH-20) manufactured by Nippon Denshoku Industries Co., Ltd. The haze (%) was calculated from the following formula.
Haze value (%) = (Td / Tt) × 100

(5) Thermal contraction rate The film was held in an oven set at a temperature of 200 ° C. for 10 minutes without tension, and the dimensional change before and after each heat treatment in the film longitudinal direction (MD) and width direction (TD). Was calculated by the following equation as the heat shrinkage rate, and the heat shrinkage rate in the longitudinal direction (MD) and the width direction (TD) was obtained.
Thermal shrinkage% = ((L0−L) / L0) × 100
However, L0: Distance between gauge points before heat treatment, L: Distance between floating points after heat treatment

(6) Thickness of coating layer A small piece of film is embedded in an epoxy resin (Epomount manufactured by Refinetech Co., Ltd.), sliced to a thickness of 50 nm together with the embedded resin using Microtome 2050 manufactured by Reichert-Jung, and transmitted. The film was observed with a scanning electron microscope (LEM-2000) at an acceleration voltage of 100 KV and a magnification of 100,000, and the thickness of the coating layer was measured.

(7) Surface resistance value Any five points were measured using a 4-probe type surface resistivity measuring device [Made by Mitsubishi Chemical Corporation, Loresta GP], and the average value was used as a representative value.

(8) Surface tension Contact angle: θw, θy of water having a known surface tension and water-containing methylene to the transparent conductive thin film using a contact angle meter (“CA-X type” manufactured by Kyowa Interface Science Co., Ltd.) It measured on 25 degreeC and 50% RH conditions. Using these measured values, the surface tension γs of the transparent conductive thin film was calculated as follows.
The surface tension γs of the transparent conductive thin film is the sum of the dispersive component γsd and the polar component γsp. That is,
γs = γsd + γsp (Formula 1)
From the Young equation,
γs = γsw + γw · cos θw (Formula 2)
γs = γsy + γy · cos θy (Formula 3)
Here, γsw is the tension acting between the transparent conductive thin film and water, γsw is the tension acting between the transparent conductive thin film and methylene iodide, γw is the surface tension of water, and γy is the surface tension of methylene iodide. It is.

From the Fowkes equation,
γ _sw = γ _s + γ _w −2 × (γ _sd · γ _wd ) ^1/2 −2 × (γ _sp · γ _wp ) ^1/2 (Formula 4)
γ _sy = γ _s + γ _y −2 × (γ _sd · γ _yd ) ^1/2 −2 × (γ _sp · γ _yp ) ^1/2 (Formula 5)
It is. Here, γ _wd is a dispersive component of the surface tension of water, γ _wp is a polar component of the surface tension of water, γ _yd is a dispersive component of the surface tension of methyl iodide, and γ _yp is a surface tension of methylene iodide. It is a polar component.

By solving the simultaneous equations of Formulas 1 to 5, the surface tension γ _s = γ _sd + γ _sp of the transparent conductive thin film can be calculated. At this time, the surface tension of water (γ _w ): 72.8 mN / m, the surface tension of methylene iodide (γ _y ): 50.5 mN / m, the dispersive component of the surface tension of water (γ _wd ): 21. 8 mN / m, polar component of surface tension of water (γ _wp ): 51.0 mN / m, dispersive component of surface tension of methylene iodide (γ _y d): 49.5 mN / m, surface tension of methylene iodide Polar component (γ _yp ): 1.3 mN / m was used.

(9) Adhesiveness of porous semiconductor layer Gauze was reciprocated 5 times at a load of 50 g / cm ^{2 on} the surface of the porous semiconductor layer, and the degree of peeling was evaluated with the aim. The case where peeling was not observed was indicated by ◯, the case where peeling was partially observed was indicated by Δ, and the case where peeling was completely observed was indicated by ×.

(10) IV characteristics (photocurrent-voltage characteristics)
A 25 mm ² large dye-sensitized solar cell was formed, and the photovoltaic power generation efficiency was calculated by the following method. A 500 W xenon lamp (made by USHIO ELECTRIC CO., LTD.) Is equipped with a correction filter for sunlight simulation (AM1.5 Global made by Oriel), and simulated solar light with an incident light intensity of 100 mW / cm ² is applied to the above photovoltaic power generation device. Irradiation was performed by changing the incident angle with respect to the horizontal plane. The system was left indoors at a temperature of 18 ° C. and a humidity of 50%. Using a current-voltage measuring device (Keutley source measure unit 238 type), the DC voltage applied to the system is scanned at a constant speed of 10 mV / second, and the photocurrent output from the device is measured, so that photocurrent-voltage The characteristics were measured, and the photovoltaic power generation efficiency was calculated.

(11) Wrinkle resistance acceleration test Using a sunshine weather meter (Suga Test Instruments Co., Ltd., WEL-SUN-HCL type), an exposure acceleration test was conducted by irradiating for 1000 hours according to JIS-K-6783. .

[Example 1]
<Creation of polyester film>
A polyethylene naphthalene dicarboxylate (inherent viscosity: 0.61) containing 0.5% by weight of an ultraviolet absorber represented by the following formula (A) is melt-extruded on a rotating cooling drum maintained at 60 ° C. did.

Subsequently, after extending | stretching 3.3 times at 140 degreeC to the vertical direction, the following coating agent A was apply | coated uniformly with the roll coater on the both surfaces.
Subsequently, this coated film was subsequently dried at 120 ° C., stretched 3.5 times at 145 ° C. in the transverse direction, and heat-set by shrinking 2% in the width direction at 240 ° C. to obtain a laminated film having a thickness of 100 μm. It was. This laminated film had a coating thickness of 0.08 μm, a light transmittance at a wavelength of 380 nm of 3.5%, a light transmittance at 400 nm of 35%, and a light transmittance at 420 nm of 84%.

<Coating agent A>
48 parts of dimethyl 2,6-naphthalenedicarboxylate, 14 parts of dimethyl isophthalate, 4 parts of dimethyl 5-sodiumsulfoisophthalate, 31 parts of ethylene glycol and 2 parts of diethylene glycol are charged into a reactor, and 0.05 part of tetrabutoxy titanium Was added and heated under a nitrogen atmosphere while controlling the temperature at 230 ° C., and the produced methanol was distilled off to conduct a transesterification reaction. Subsequently, the temperature of the reaction system was gradually raised to 255 ° C., and the pressure inside the system was reduced to 1 mmHg to carry out a polycondensation reaction to obtain a polyester. 25 parts of this polyester was dissolved in 75 parts of tetrahydrofuran, and 75 parts of water was dropped into the resulting solution under high-speed stirring at 10,000 rpm to obtain a milky white dispersion. Then, this dispersion was subjected to a reduced pressure of 20 mmHg. Distillation was performed, and tetrahydrofuran was distilled off to obtain an aqueous dispersion of polyester having a solid content of 25% by weight.

  Next, 3 parts of sodium lauryl sulfonate as a surfactant and 181 parts of ion-exchanged water are charged into a four-necked flask and the temperature is raised to 60 ° C. in a nitrogen stream, and then 0.5% ammonium persulfate is used as a polymerization initiator. Part, 0.2 part of sodium hydrogen nitrite is added, and further monomers are methyl methacrylate 30.1 parts, 2-isopropenyl-2-oxazoline 21.9 parts, polyethylene oxide (n = 10) methacrylic acid A mixture of 39.4 parts and 8.6 parts of acrylamide was added dropwise over 3 hours while adjusting the liquid temperature to 60 to 70 ° C. After the completion of dropping, the reaction was continued with stirring while maintaining the same temperature range for 2 hours, and then cooled to obtain an acrylic aqueous dispersion having a solid content of 35% by weight.

  On the other hand, 0.2% by weight of silica filler (average particle size: 100 nm) (trade name Snowtex ZL manufactured by Nissan Chemical Co., Ltd.), polyoxyethylene (n = 7) lauryl ether (Sanyo Chemical Co., Ltd.) as a wetting agent An aqueous solution containing 0.3% by weight of the trade name NAROACTY N-70) was prepared.

  Coating agent A was prepared by mixing 10 parts by weight of the above polyester aqueous dispersion, 5 parts by weight of the acrylic water dispersion and 85 parts by weight of the aqueous solution.

<Hard coat>
Using the obtained laminated film, a UV curable hard coat agent (Desolite R7501 manufactured by JSR) was applied to the easy-contact layer side so as to have a thickness of about 5 μm, and UV cured to form a hard coat layer.

<Transparent conductive layer formation>
A transparent conductive layer made of ITO having a film thickness of 400 nm was formed on one surface on which the hard coat layer was formed by a direct current magnetron sputtering method using an ITO target (tin concentration was 10% by weight in terms of tin dioxide). The transparent conductive layer is formed by sputtering, after the chamber is evacuated to 5 × 10 ⁻⁴ Pa before plasma discharge, and then a mixed gas of argon and oxygen (oxygen concentration is 0.5% by volume) is introduced into the chamber. Then, the pressure was set to 0.3 Pa, and 1000 W was applied to the ITO target. The surface resistance value of the transparent conductive layer was 15Ω / □.

  Next, using a normal pressure plasma surface treatment apparatus (AP-T03-L manufactured by Sekisui Chemical Co., Ltd.), the surface of the transparent conductive layer was subjected to plasma treatment at 1 m / min under a nitrogen stream (60 L / min). At this time, the surface resistance value was 16Ω / □, and the surface tension was 70.5 mN / m.

<Antireflection layer formation>
On the surface opposite to the surface on which the transparent conductive layer of the laminated film is formed, a TiO _X layer having a thickness of 80 nm and a refractive index of 1.75, a TiO ₂ layer having a thickness of 70 nm and a refractive index of 2.1, and On top of that, SiO ₂ having a thickness of 95 nm and a refractive index of 1.45 was formed by a high frequency sputtering method to form an antireflection layer. In forming each electrostatic thin film, the degree of vacuum was 5 × 10 ⁻⁴ Torr, and Ar: 55 sccm and O ₂ : 5 sccm were flowed as gases. The substrate was kept at room temperature without heating or cooling during the film forming process.

<Porous semiconductor layer formation>
On the transparent conductive layer of the laminated film, a commercially available paste for forming a low-temperature-forming porous titanium dioxide layer (SP-200 manufactured by Showa Denko) is applied with a bar coater and heat-treated at 160 ° C. for 30 minutes in the atmosphere. And a porous titanium dioxide layer was formed to a thickness of 4 μm to prepare an electrode of a dye-sensitized solar cell. When the adhesion was evaluated, no peeling was observed and the evaluation was good.

<Creation of dye-sensitized solar cell>
This electrode was immersed in a 300 μM ethanol solution of a ruthenium complex (Ru535bisTBA, Solaronix) for 24 hours to adsorb the ruthenium complex on the surface of the photoactive electrode. A counter electrode was prepared by depositing a Pt film on the transparent conductive layer of the laminated film by sputtering. The electrode and the counter electrode are overlapped via a thermocompression-bondable polyethylene film frame spacer (thickness 20 μm), the spacer portion is heated to 120 ° C., and both electrodes are pressure-bonded. Further, the edge portion is sealed with an epoxy resin adhesive. After injecting an electrolyte solution (3-methoxypropionitrile solution containing 0.5% lithium iodide, 0.05M iodine, 0.5M tert-butylpyridine, 3% by weight of nylon beads having an average particle size of 20 μm) And sealed with an epoxy adhesive.

As a result of performing IV measurement (effective area 25 mm ² ) of the completed dye-sensitized solar cell, the open circuit voltage, short circuit current density, and fill factor were 0.70 V, 6.2 mA / cm ² , 0.56, respectively. As a result, the photovoltaic power generation efficiency was 2.5%.

Next, a weather resistance test was performed and IV measurement was performed. The open-circuit voltage, short-circuit current density, and fill factor are 0.69 V, 5.9 mA / cm ² , and 0.57, respectively. As a result, the photovoltaic efficiency is 2.4%, and the photovoltaic efficiency is greatly reduced. It was small.

[Example 2]
A polyester film was prepared in the same manner as in Example 1 except that the addition amount of the ultraviolet absorber contained in polyethylene terephthalate was changed to 1% by weight. The light transmittance at a wavelength of 380 nm was 3.0%, the light transmittance at 400 nm was 29%, and the light transmittance at 420 nm was 84%.

  Similarly to Example 1, a hard coat layer and a transparent conductive layer were provided. The surface resistance value of the transparent conductive layer surface was 20Ω / □. Next, using the atmospheric pressure plasma surface treatment apparatus used in Example 1, plasma treatment was performed on the surface of the transparent conductive layer at a rate of 1 m / min in a mixed gas stream of oxygen 30% and nitrogen 70% (60 L / min). went. At this time, the surface resistance value was 21Ω / □, and the surface tension was 43.2 mN / m.

  Further, in the same manner as in Example 1, an antireflection layer and a porous semiconductor layer were formed to produce an electrode. When the adhesion evaluation of the porous semiconductor layer was performed, no peeling was observed, and the evaluation was good.

Using this electrode, a dye-sensitized solar cell was prepared in the same manner as in Example 1 and subjected to IV measurement (effective area 25 mm ² ). As a result, the open-circuit voltage, short-circuit current density, and fill factor were 0. 73 V, 6.1 mA / cm ² , 0.56. As a result, the photovoltaic efficiency was 2.6%.

Next, a weather resistance test was performed and IV measurement was performed. The open circuit voltage, short circuit current density, and fill factor are 0.74 V, 5.9 mA / cm ² , and 0.55, respectively. As a result, the photovoltaic efficiency is 2.5%, and the degradation of photovoltaic efficiency is extremely low It was small.

[Comparative Example 1]
A dye-sensitized solar cell electrode was prepared in the same manner as in Example 1 except that no ultraviolet absorber was added to polyethylene terephthalate. The light transmittance of the polyester film at a wavelength of 380 nm was 22%, the light transmittance at 400 nm was 81.0%, and the light transmittance at 420 nm was 86.0%. Using this electrode, a dye-sensitized solar cell was prepared in the same manner as in Example 1 and subjected to IV measurement (effective area 25 mm ² ). As a result, the open-circuit voltage, short-circuit current density, and fill factor were 0. 71 V, 6.3 mA / cm ² , 0.57. As a result, the photovoltaic power generation efficiency was 2.6%.

Next, a weather resistance test was performed and IV measurement was performed. The open circuit voltage, short circuit current density, and fill factor are 0.63 V, 2.2 mA / cm ² , and 0.56, respectively. As a result, the photovoltaic efficiency is 0.8%, and the photovoltaic efficiency is significantly reduced. Met.

  The laminated film for a dye-sensitized solar cell of the present invention can be used as a member of a dye-sensitized solar cell.

Claims (6)

  A polyester film having a light transmittance at a wavelength of 380 nm of 5% or less, a light transmittance at 400 nm of 50% or less and a light transmittance at 420 nm of 70% or more, and a surface tension provided on one side thereof of 40 mN / A laminated film for a dye-sensitized solar cell, comprising a transparent conductive layer of m or more.   The laminated film for a dye-sensitized solar cell according to claim 1, wherein the transparent conductive layer has a surface tension of 65 mN / m or more.   The laminated film for dye-sensitized solar cells according to claim 1 or 2, wherein the polyester film contains 0.05 to 30% by weight of an ultraviolet absorber. The ultraviolet absorber contained in the polyester film is represented by the following formula (I)

And a cyclic imino ester represented by the following formula (II)

(Where A is the following formula (II) -a

Or a group represented by the following formula (II) -b

R ₁ and R ₂ are the same or different and are monovalent hydrocarbon residues; X ₃ is a naphthalene ring residue. )
The laminated film for dye-sensitized solar cells according to claim 3, which is at least one compound selected from cyclic iminoesters represented by:   The laminated film for a dye-sensitized solar cell according to any one of claims 1 to 4, wherein the laminated film has an antireflection layer on a surface opposite to the transparent conductive layer.   The laminated film for dye-sensitized solar cells according to any one of claims 1 to 5, and titanium oxide, zinc oxide and tin oxide provided on the transparent conductive layer of the laminated film for dye-sensitized solar cells An electrode for a dye-sensitized solar cell comprising a porous semiconductor layer made of at least one oxide selected from the group consisting of: