JP2011048959A - Electrode sheet for dye-sensitized solar cell, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of fabricating a durable current-collecting wire protective membrane in which the protective membrane has such a multi-layered constitution that after the protective membrane composed of a fluorine polymer compound is formed on the current-collecting wire, the protective membrane composed of a photopolymerized compound durable in ultra-violet ozone is formed in order to have superior resistance against electrolytic liquid used for a dye-sensitized solar cell, improving power generating characteristics, and sufficiently protecting the current-collecting wire against an electrolyte. <P>SOLUTION: An electrode sheet has a semiconductor porous layer and a metallic current-collecting wire on a transparent conductive layer of a transparent substrate having the transparent conductive layer. In the electrode sheet, the protective membrane composed of the fluorine polymer compound is formed on the metallic current-collecting wire, and the protective membrane is covered with the membrane in which a photopolymerized compound is cured. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a dye-sensitized solar cell electrode sheet excellent in durability. Specifically, an electrode sheet for a dye-sensitized solar cell that uses a composition that functions as a protective film for a current collector that has excellent workability and has excellent electrolyte sealing performance in a dye-sensitized solar cell, and its It relates to a manufacturing method.

  In a dye-sensitized solar cell, it is indispensable to provide an electrolyte layer between a semiconductor electrode and a counter electrode, and an electrolyte solution containing iodine or the like is generally used for the electrolyte layer. On the other hand, a current collector for deriving the generated electric power is attached to the electrode, and silver or copper having high conductivity is often applied by printing or the like to form the current collector. However, iodine, etc. contained in the electrolyte solution forming the electrolyte layer easily binds to the metal forming the current collector and dissolves the metal, thereby losing the electrical conductivity of the current collector and significantly reducing power generation efficiency. There is a fear.

  In order to cope with these problems, a metal wiring layer and a transparent conductive layer electrically connected to the metal wiring layer are provided, and the metal wiring layer is insulated by an insulating layer mainly composed of heat-resistant ceramics. An electrode substrate of a dye-sensitized solar cell is disclosed (for example, Patent Document 1). In addition, an example is disclosed in which a protective layer can be easily formed by plating the current collector or by forming an oxide film to protect the current collector. (For example, Patent Document 2 and Patent Document 3)

  Thus, for the current collector of the dye-sensitized solar cell, for example, when the conventional current collector described in Patent Document 1 is used, the arranged current collector is covered with an insulating material containing heat-resistant ceramics or a glass component. It is necessary and the process becomes complicated, and it is difficult to make the thickness of the insulating layer to be coated constant, and the power generation efficiency is reduced by covering an extra portion, or the portion where the coating is not sufficient May occur, resulting in insufficient protection of the current collector. The method of forming a current collector described in Patent Document 2 is based on one or both of an alkaline solution and an organic solvent using a photoresist agent on a conductive film or a photoelectrode layer formed on a substrate. A layer forming step of forming a strippable photoresist agent layer excluding a portion where a current collector is formed, and plating for forming a current collector by performing metal plating on a portion where the photoresist agent layer is not applied And a peeling step for peeling the photoresist agent layer from the conductive film. The photoresist has a long process, and an unnecessary portion of the resist must be removed with a solvent or the like. In addition, manufacturing costs are also incurred. Furthermore, since photoresist is liable to cause defects at the time of peeling, it is difficult to say that the yield is poor and it is extremely practical.

  Therefore, it is still possible to provide a protective film resistant to the electrolyte, as well as providing the current collector by printing with silver or copper, in order to improve the yield and further improve the performance of the dye-sensitized solar cell. Is necessary.

  Recently, a fluoropolymer compound has been introduced as a sealing material resistant to electrolytes. Originally fluorinated materials are hard and poor in chemical resistance, but due to their low surface tension, their adhesion to various base materials is inferior, so they have the disadvantage of poor workability, but they incorporate an ether bond in the skeleton. Thus, since there is a silicon group that is flexible even at room temperature and has a high reactivity at the skeleton end, it can be cured by a hydrosilyl reaction using a thermal catalyst.

  With this compound, it is fluid at room temperature, so it is possible to screen-print with this compound after creating a current collector, and to have a very good electrolyte resistance with moderate elasticity by heat treatment. Therefore, it is a material suitable as a protective film for collecting current collector. (Patent Document 4)

  However, when creating a dye-sensitized solar cell, there are steps required to increase the photoelectric conversion efficiency. For example, the organic matter contamination of the semiconductor porous electrode causes a decrease in the photoelectric conversion efficiency. It is known to apply UV ozone irradiation treatment to metal oxide semiconductor electrodes (Patent Document 5), but created a protective film made of fluoropolymer compound to cover the current collector formed on the substrate After that, when the UV ozone treatment is performed, the protective film of the above-mentioned fluoropolymer compound becomes brittle and destroyed, and as a result, the electrolyte penetrates and the electric wire is destroyed. There was a fatal defect that could not be used as. On the other hand, the film made of the fluoropolymer compound alone was not contaminated by the electrolyte as described above, but the power generation characteristic was significantly lowered due to organic contamination, and this was not practically usable.

  In addition, after forming a semiconductor porous electrode on a substrate and then performing UV ozone treatment, when forming a current collector or forming a protective film, a large amount of organic matter is contaminated at that time, resulting in a UV ozone treatment effect. Since it reduces, it is not preferable. For this reason, UV ozone treatment is most suitable for forming a semiconductor porous electrode by forming a current collector on a substrate and then forming a protective film and then performing UV ozone treatment. The UV ozone treatment is not particularly limited before and after forming the metal oxide semiconductor electrode.

By the way, generally, the functions shown in the following items (1) to (4) are regarded as important for the protection of the collector line of the dye-sensitized solar cell.
(1) Solvent resistance that electrolytes (such as acetonitrile) do not penetrate into the membrane,
(2) iodine resistance in which iodine contained in the electrolyte does not penetrate into the membrane;
(3) Self-adhesiveness that does not create a gap with the electrode substrate,
(4) resistance to oxidation treatment,
It is. Here, the reason why the above items (1) and (2) are regarded as important is to prevent a decrease in power generation characteristics due to destruction of the collector line due to electrolyte penetration. The reason why the above item (3) is regarded as important is to prevent power generation characteristics from being deteriorated due to leakage and intrusion from the air gap. Moreover, the reason why the above item (4) is regarded as important is that it is an indispensable process for producing a high-performance photoelectrode.

  In light of such requirements, elastic materials having electrolyte resistance that are easy to process have already been introduced. Materials that have an olefin hydrocarbon skeleton in the main chain, that is, an alkene structure, are inherently highly hydrophobic and are considered to be resistant to various electrolytes, such as polyethylene, polypropylene, polybutadiene, polyisoprene, and amorphous polyalphaolefin. Typical examples of such olefin polymers and modified products thereof. For example, as disclosed in Patent Document 6, when a sealing material is formed using hydrogenated polybutadiene acrylate and polyisobutylene, a photopolymerization initiator and an acrylate-based elastic material, resistance to organic solvents such as acetonitrile is good, but long-term In this case, the iodine resistance is poor, and the power generation characteristics may be deteriorated due to leakage of the electrolyte. In addition, in a composition in which polyisobutylene, which is a saturated elastomer, is blended in a proportion of 20 to 80 parts by weight with respect to 100 parts by weight of hydrogenated polybutadiene acrylate, the adhesiveness after curing does not disappear, and as a protective material for a current collector Unsuitable. Further, the organic solvent and iodine resistance contained in the electrolyte are remarkably superior in the fluoropolymer system.

  Furthermore, although the composition comprising hydrogenated polybutadiene acrylate, polyisobutylene, photopolymerizable initiator, extender pigment, and monofunctional monomer as a photopolymerizable composition is resistant to UV ozone treatment, it is a long-term viewpoint from the viewpoint of electrolyte resistance. Then, it is inferior to the fluoropolymer system.

  Therefore, the current situation is that a current collector protective material having all the functions shown in the items (1) to (4) has not yet been obtained.

JP 2005-78857 A JP 2006-342100 A JP 2006-286434 A JP 2007-286434 A JP 2005-203360 A JP 2006-008819 A

  The present invention has an excellent resistance to an electrolyte used in a dye-sensitized solar cell, improves power generation characteristics, and sufficiently protects the current collector from the electrolyte. After providing a protective film made of a compound, a protective film made of a photopolymerizable compound that can withstand UV ozone is formed. Its purpose is to provide a method.

  As a result of intensive studies by the present inventors, when a protective film is formed on the current collector, a film made of a fluorine polymer compound having excellent electrolyte resistance is first provided, and then a light having a strong film resistant to UV ozone treatment is provided. The present inventors have found that by forming a plurality of so-called protective films provided with a film made of a polymerizable composition, a protective film having the ability to withstand UV ozone treatment while having electrolyte resistance can be obtained.

  That is, the present invention is an electrode sheet having a semiconductor porous layer and a metal current collector on the transparent conductive layer of a transparent substrate having a transparent conductive layer, and comprising a fluoropolymer compound on the metal current collector The present invention relates to an electrode sheet in which a film is provided and the protective film is further coated with a film obtained by curing a photopolymerizable composition.

  The present invention also relates to the above electrode sheet, wherein the fluoropolymer compound includes a fluorinated polyether skeleton and a silicon skeleton.

  The present invention also relates to the above electrode sheet, wherein the photopolymerizable composition comprises polyalkene acrylate, polyalkene, photopolymerizable initiator, extender pigment, and monofunctional monomer.

  The present invention also relates to the above electrode sheet, wherein the polyalkene acrylate is polybutadiene having a (meth) acryl group at the terminal and hydrogenated main skeleton.

  Moreover, this invention relates to the said electrode sheet characterized by polyalkene being less than 20 weight part with respect to 100 weight part of polyalkene acrylate.

  The present invention also relates to the above electrode sheet, wherein the transparent substrate is a resin substrate.

  The present invention also provides a dye-sensitized solar cell in which the electrode sheet and the counter electrode are arranged to face each other with an electrolyte, and the dye having a sensitizing dye adsorbed on the semiconductor porous layer of the electrode sheet The present invention relates to a sensitized solar cell.

  The present invention is also a method for producing the above electrode sheet, wherein a protective film made of a fluoropolymer compound is provided on a metal collector wire, and the protective film is further covered with a film obtained by curing the photopolymerizable composition. The present invention relates to a method for producing an electrode sheet, which includes Step 1, Step 2 of forming a semiconductor porous layer on the transparent conductive layer, and Step 3 of performing UV ozone treatment.

  The current collector protective material for a dye-sensitized solar cell according to the present invention has a laminated structure of an electrolyte resistant film composed of a fluorine-based polymer and a UV ozone resistant film made of a photopolymerizable compound. Therefore, it has excellent resistance to the electrolyte (acetonitrile, etc.) enclosed in the dye-sensitized solar cell, can prevent deterioration in power generation characteristics due to electrolyte leakage, and gas generated from the electrolyte It has low permeability such as (volatile solvent, sublimated iodine, etc.), is strong against oxidation treatment such as UV ozone, and prevents power generation characteristics from being reduced due to reduction in redox capacity due to gas leakage. Can do.

  A protective film in direct contact with the current collector has a linear fluoropolyether compound having at least two alkenyl groups in one molecule and a perfluoropolyether structure in the main chain of the molecule, and one molecule It is used as a solar cell because the current collector is not attacked by the electrolyte when it is composed of an organic silicon compound having at least two hydrosilyl groups therein and a hydrosilylation reaction catalyst as essential components. Stable electricity can be collected even when the ambient temperature changes. In addition, since the protective film itself has excellent elasticity and does not lose rubber elasticity even at low temperatures, it has resistance to compression set against the weight of the electrode substrate and low modulus to follow electrode substrate deformation that changes with temperature changes. It becomes good. This is because the three-dimensional cross-linked structure is made, and therefore, the electrolytic solution resistance and the adhesion to the electrode substrate are further improved.

FIG. 1 is a schematic side sectional view of a dye-sensitized solar cell test sample.

  The present invention will be specifically described below with reference to the drawings.

  FIG. 1 shows an embodiment of a method for forming a current collector for a dye-sensitized solar cell according to the present invention, and is a cross-sectional view showing a formed electrode substrate. A transparent conductive layer 2 is formed on the transparent substrate 1, and a metal collecting wire 3 is provided in a strip shape on the conductive layer 2. Before and after the metal collector wire 3 is provided, a protective film 4 made of a fluoropolymer compound, and a protective film 5 made of a cured film of a photopolymerizable composition are provided to form a semiconductor porous layer 8 adsorbing a dye. After the UV ozone treatment, the dye is adsorbed on the porous semiconductor layer to obtain an electrode sheet. The opposing counter electrode is formed by forming the conductive layer 11 on the substrate 10 and providing the metal collector wire 3 in a strip shape on the conductive layer 11. After the metal collector wire 3 is provided, a protective film 4 made of a fluoropolymer compound is present as an essential component. At this time, the counter electrode may or may not have the protective film 5 made of a cured film of the photopolymerizable composition. The electrode sheet and the counter electrode are bonded together via the main seal material 7, and at this time, the electrolyte 6 is sealed to complete the dye-sensitized solar cell.

(Electrode sheet)
(Transparent substrate with a transparent conductive layer)
The transparent substrate used for the electrode having an electrically conductive surface is not particularly limited as long as it is a material that absorbs less light from the visible to the near infrared region of sunlight. Glass substrates such as quartz, ordinary glass, BK7, lead glass, polyethylene terephthalate, polyethylene naphthalate, polyimide, polyester, polyethylene, polycarbonate, polyvinyl butyrate, polypropylene, tetraacetylcellulose, syndiocta polystyrene, polyphenylene sulfide, polyarylate, Resin substrates such as polysulfone, polyester sulfone, polyetherimide, cyclic polyolefin, brominated phenoxy, and vinyl chloride can be used. Among these, polyethylene naphthalate is excellent in terms of heat resistance and transparency, but is not limited thereto.

(Transparent conductive layer)
The transparent conductive layer is not particularly limited as long as it is a conductive material that absorbs little light from the visible to the near infrared region of sunlight. However, ITO (indium-tin oxide) or tin oxide (fluorine-doped material) can be used. Metal oxides having good electrical conductivity such as zinc oxide are preferable.

  The transparent conductive layer is formed on the transparent substrate by vapor deposition, and the film thickness is about 0.1 to 1 μm.

(Metal collector)
The metal collector wire is formed by screen printing on the transparent conductive layer, and is divided into about 50 mm at equal intervals in the vertical direction. The width of the formed metal power collection wire is about 0.1 to 1.0 mm.

  The metal collector wire can be prepared by a known method such as a printing method using a silver paste, a metal foil transfer method, or a plating method using a photoresist. In the present invention, a method of forming a current collector with a silver paste is preferable, but the present invention is not limited thereto.

(Protective film)
Next, an example of a method for forming a protective film is shown. First, a protective film made of a fluoropolymer compound is printed on the metal current collector formed on the transparent conductive layer on the transparent substrate so as to completely cover the metal current collector by screen printing, and then dried. Thus, a protective film made of a fluoropolymer having a film thickness of about 4 to 20 μm is formed. With this protective film sufficiently dried, a protective film made of a photopolymerizable composition composed of urethanized polybutadiene acrylate, polyisobutylene, photopolymerizable initiator, extender pigment, and monofunctional monomer is screen printed by 4 to 4 Print to a thickness of 10 μm. Then, the entire surface is exposed by an ultraviolet irradiation device, cured by reaction, and a metal collector wire with a protective film is formed on the transparent conductive layer.

  There is no particular limitation as long as a fluorine-based polymer excellent in electrolyte resistance is used to protect the metal collector wire, but preferably it has at least two alkenyl groups in one molecule, A material comprising a linear fluoropolyether compound having a perfluoropolyether structure in the main chain, an organosilicon compound having at least two hydrosilyl groups in one molecule, and a hydrosilylation reaction catalyst as essential components is used. . That is, by using such a material, excellent elasticity is obtained, and the compression set resistance against the weight of the electrode substrate and the low modulus following the deformation of the electrode substrate are improved, and the three-dimensional crosslinking is also achieved. Thus, the electrolytic solution resistance and the adhesion to the electrode substrate are excellent.

  The specific linear fluoropolyether compound having an alkenyl group is not particularly limited, and preferred examples include those represented by the following general formula (1).

  Further, it is necessary that one molecule of the fluoropolyether compound has at least two alkenyl groups. Examples of the alkenyl group include vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group and the like.

  As the curing agent used together with the specific linear fluoropolyether compound having the alkenyl group, as described above, an organosilicon compound having at least two hydrosilyl groups in one molecule is used. The hydrosilyl group refers to a group in which a hydrogen atom is bonded to at least one of four bonds of a silicon atom.

  The hydrosilylation reaction catalyst used together with the fluoropolyether compound and the organosilicon compound is not particularly limited as long as it can exhibit a catalytic function for the crosslinking reaction. For example, chloroplatinic acid, chloroplatinic acid and alcohol, aldehyde , Complexes with ketones, platinum / vinyl siloxane complexes, platinum / olefin complexes, platinum / phosphite complexes, platinum, alumina, silica, carbon black and the like on which solid platinum is supported. Examples of catalysts other than platinum compounds include palladium compounds, rhodium compounds, iridium compounds, ruthenium compounds and the like. These may be used alone or in combination of two or more.

  Examples of the organosilicon compound include organohydrogenpolysiloxane. The organohydrogenpolysiloxane here refers to a polysiloxane having a hydrocarbon group or a hydrogen atom on the Si atom.

  For example, “Syfer 2662” manufactured by Shin-Etsu Chemical Co., Ltd. can be cited as an optimal compound containing a fluorine-based polymer. Although it is a material that can be cured at a low temperature, it may be made by itself if necessary.

  Next, a protective film composed of a cured film of a photopolymerizable composition that can be used in the present invention will be described. A protective film made of a cured film of a photopolymerization composition is formed on a protective film made of a fluoropolymer compound as a base, and adheres well, and forms a strong film that can withstand UV ozone treatment and an electrolyte in a subsequent process. The

  The protective film made of a cured film of the photopolymerizable composition preferably has a composition that adheres well to the film made of a fluoropolymer, and is preferably a material having high hydrophobicity and rubber elasticity at room temperature. In particular, if the composition is composed of urethane-modified hydrogenated polybutadiene and polyisobutylene having an acrylic group at the end, a photopolymerization initiator and isoboronyl acrylate, it is used for adsorbing dyes to metal oxide semiconductors as well as electrolyte resistance. The composition is resistant to solvents. In addition, a composition having resistance to a solvent used for adsorbing the dye to the metal oxide semiconductor film is preferable.

  However, when a sealing material was formed using hydrogenated polybutadiene acrylate and polyisobutylene, a photopolymerization initiator and an acrylate-based elastic material, polyisobutylene was blended in less than 20 parts by weight with respect to 100 parts by weight of hydrogenated polybutadiene acrylate. In composition, since the adhesiveness after reaction hardening lose | disappears, it is suitable as a protective material for collector wires. On the other hand, when the amount of polyisobutylene is 20 parts by weight or more, the adhesiveness after curing does not disappear and film breakage tends to occur, which is not preferable.

(UV ozone treatment)
After the formation of the protective film by the cured film of the photopolymerizable composition, a semiconductor porous layer is prepared, and UV ozone treatment is performed before and after that.

  The UV ozone treatment may be performed either before or after the formation of the semiconductor porous layer. If there is no concern about contamination with organic substances, the UV ozone treatment may be performed before the semiconductor porous layer is formed before the dye is adsorbed.

  The UV ozone treatment is performed on the same surface where the metal current collector is formed so that it does not overlap with the metal current collector or the current collector protective film, but before and after the formation of the semiconductor porous layer. Either may be sufficient. In the dye-sensitized photo semiconductor electrode of the present invention, the amount of current generated by the battery when it is incorporated into a dye-sensitized solar cell depends on the amount of dye adsorbed on the semiconductor porous layer and the bonding state. The performance can be improved by performing an oxidation treatment before and after the formation of the semiconductor porous layer before the dye adhesion. As the oxidation treatment method, any treatment method that can oxidize the surface of the semiconductor porous layer may be used, but the UV ozone treatment method can most effectively remove unnecessary organic substances that lower the photoelectric conversion efficiency.

More specifically, UV (ultraviolet light) is irradiated to a substrate formed up to a protective film made of a cured film of a photopolymerizable composition in the presence of oxygen. Examples of the light source include sunlight, a high-pressure mercury lamp, and a xenon lamp. Irradiation intensity 0.001 ~10W / cm ^2, more 0.01 to 10 W / cm ² is preferred. If the irradiation intensity is lower than this, the oxidation does not proceed sufficiently. The treatment temperature is preferably -50 ° C to 400 ° C, more preferably 0 ° C to 200 ° C. If the temperature is higher than this, excessive oxidation occurs, and if it is lower, the oxidation does not proceed sufficiently. The treatment time is preferably 0.1 minute to 50 hours, more preferably 1 minute to 10 hours. If the time is longer than this, excessive oxidation occurs, and if it is shorter, the oxidation does not proceed sufficiently. Oxygen present in the atmosphere is activated by irradiating UV (ultraviolet rays) to the atmosphere containing oxygen compounds that generate ozone by UV (ultraviolet rays) irradiation, or the semiconductor porous layer, as well as oxygen-containing gases such as air. Any atmosphere containing oxygen or an oxygen compound capable of reacting on the surface of the semiconductor porous layer may be used.

(Semiconductor porous layer adsorbing dye)
The semiconductor porous layer adsorbing the dye is formed by applying and drying a paste containing metal oxide semiconductor particles and a metal atom complex on the transparent conductive layer, and then dissolving the dye in a solvent and performing immersion drying. The target photoelectrode is obtained.

  Examples of the material as the metal oxide semiconductor particles contained in the semiconductor porous layer used in the present invention include silicon, germanium, III-V group semiconductor, and metal chalcogenide. In addition, mention may be made of titanium oxide, tin oxide, tungsten oxide, zinc oxide, indium oxide, niobium oxide, iron oxide, nickel oxide, cobalt oxide, strontium oxide, tantalum oxide, antimony oxide, lanthanoid oxide, yttrium oxide, vanadium oxide, etc. However, these make a paste with a metal atom complex in the same solution, sinter by heating after film formation to form a semiconductor porous layer, and further connect a sensitizing dye to visible light and / or The present invention is not limited to this as long as photoelectric conversion up to the near infrared region is possible. In order for the semiconductor porous layer surface to be sensitized by the sensitizing dye, it is desirable that the conduction band of the semiconductor porous layer be present at a position where electrons are easily received from the photoexcitation order of the sensitizing dye. For this reason, titanium oxide, tin oxide, zinc oxide, niobium oxide and the like are particularly used among the metal oxide semiconductor particles. Further, titanium oxide is particularly used from the viewpoint of price and environmental hygiene. In the present invention, one or a plurality of types can be selected and combined from the metal oxide semiconductor particles and the metal oxide semiconductor particles as the metal oxide semiconductor particles having an average particle diameter of 100 nm or less. As the crystal structure of titanium oxide, rutile type (tetragonal high temperature type), anatase type (tetragonal low temperature type), and brookite type (orthorhombic crystal) are known. In the present invention, the anatase type is preferably an alkali metal. Is preferably used because it can contain.

  The metal atom complex used in the present invention can be printed with a material that can be adsorbed on the surface of the metal oxide semiconductor particles and function as a dispersing agent. Furthermore, after this paste is applied to the transparent conductive layer to form a semiconductor porous layer, it can provide high adhesion and conversion efficiency.

  The formation of the semiconductor porous layer can be made, for example, from metal oxide semiconductor particles described in JP-A 2009-16224, for example, titanium oxide paste. As a matter of course, the semiconductor porous layer is formed on the transparent conductive layer other than the protective film of the current collector covered with the photopolymerizable composition.

  The dye adsorbed on the semiconductor porous layer has a role of injecting excited electrons by absorbing light in a wavelength region where the semiconductor porous layer cannot photoelectrically convert into the valence band of the semiconductor porous layer. Ruthenium dyes (N719 dye, etc.) that can be obtained from Pexel Technologies, etc. are typical examples, but there are concerns about resource depletion and cost in terms of using rare elements, and in recent years organic sensitization that replaces this has been a concern. Many pigments have been developed. Coumarin-based, cyanine-based, rhodanine-based, squarylium-based, diketopyrrolopyrrole-based, phenylene vinylene-based, fluorene-based dyes, merocyanine-based dyes, and the like, which can also be used as the sensitizing dye of the present invention. Some of these organic dyes exhibit a bright red or blue color, and there is an advantage that they can be selected and used according to the use in which design properties are emphasized. Among these organic dyes, merocyanine dyes of Mitsubishi Paper Industries Co., Ltd. are well known, and D77, D102, D149, etc. can be obtained from the company, but are not limited to these as long as they exhibit functions.

  The solvent for preparing the dye solution needs to be a solvent that dissolves the dye and can mediate dye adsorption on the metal oxide layer. In order to dissolve the sensitizing dye, heating, addition of a solubilizing agent, and filtration of insoluble matter may be performed as necessary. Two or more types of solvents may be used as a mixture, such as ethanol, isopropyl alcohol, benzyl alcohol and other alcohol solvents, acetonitrile, propionitrile and other nitrile solvents, ethyl acetate, butyl acetate and other esters. Solvents, ketone solvents such as acetone, methyl ethyl ketone and cyclohexanone, carbonate solvents such as diethyl carbonate and propylene carbonate, carbohydrate solvents such as hexane, octane, toluene and xylene, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, 1 , 3-dimethylimidazolinone, N-methylpyrrolidone, water and the like can be used, but are not limited thereto.

(Counter electrode)
The conductive counter electrode used in the present invention functions as a positive electrode of a dye-sensitized solar cell, and has a conductive layer formed on a substrate. Specific examples of the material for the conductive layer used for the counter electrode include metals (for example, platinum, gold, silver, copper, aluminum, rhodium, indium, etc.), metal oxides (ITO (indium-tin oxide)) and FTO ((fluorine-doped oxide). Tin), zinc oxide), carbon, etc. The film thickness of the conductive layer of the counter electrode is not particularly limited, but is preferably 5 nm or more and 10 μm or less. An organic material such as a material or a polyethylene naphthalate film can be used, but is not limited thereto.

(Electrolyte layer)
The electrolyte layer used in the present invention is preferably composed of an electrolyte, a medium, and an additive. The electrolyte of the present invention is a mixture of I ₂ and iodide (for example, LiI, NaI, KI, CsI, MgI ₂ , CaI ₂ , CuI, tetraalkylammonium iodide, pyridinium iodide, imidazolium iodide, etc.), Br ₂ Mixtures of bromide and bromide (for example, LiBr, etc.), molten salts described in Inorg. Chem. 1996, 35, 1168-1178, etc. can be used, but not limited thereto. Among these, electrolytes in which LiI, pyridinium iodide, imidazolium iodide, etc. are mixed as a combination of I2 and iodide are preferable in the present invention, but are not limited to this combination.

The preferable electrolyte concentration is 0.01 M to 0.5 M in the medium I ₂ and 0.1 M to 15 M in the iodide mixture.

  The medium used for the electrolyte layer in the present invention is desirably a compound that can exhibit good ionic conductivity. Solution media include ether compounds such as dioxane and diethyl ether, chain ethers such as ethylene glycol dialkyl ether, propylene glycol dialkyl ether, polyethylene glycol dialkyl ether, and polypropylene glycol dialkyl ether, methanol, ethanol, and ethylene glycol monoalkyl. Alcohols such as ether, propylene glycol monoalkyl ether, polyethylene glycol monoalkyl ether, polypropylene glycol monoalkyl ether, polyhydric alcohols such as ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, glycerin, acetonitrile, glutarodinitrile, Methoxyacetonitrile, propioni Lil, nitrile compounds such as benzonitrile, ethylene carbonate, carbonate compounds such as propylene carbonate, 3-methyl-2-oxazolidinone heterocyclic compounds such as dimethyl sulfoxide, can be used aprotic polar substances such as sulfolane, water, and the like.

  In addition, a polymer can be included for the purpose of using a solid (including gel) medium. In this case, a polymer such as polyacrylonitrile or polyvinylidene fluoride is added to the solution-like medium, or a polyfunctional monomer having an ethylenically unsaturated group is polymerized in the solution-like medium to make the medium solid. To do.

  As the electrolyte layer, an electrolyte that does not require CuI or CuSCN medium, and 2,2 ′, 7,7′-tetrakis (N, N—) described in Nature, Vol. 395, 8 Oct. 1998, p583-585. Hole transport materials such as di-p-methoxyphenylamine) 9,9'-spirobifluorene can be used.

  The electrolyte layer used in the present invention may contain an additive that functions to improve the electrical output of the dye-sensitized solar cell or improve the durability. Examples of additives that improve electrical output include 4-t-butylpyridine, 2-picoline, 2,6-lutidine, and cyclodextrin. MgI etc. are mentioned as an additive which improves durability.

(How to assemble)
A dye-sensitized solar cell is formed by combining the electrode sheet of the present invention and the counter electrode described above via an electrolyte layer. In order to prevent leakage and volatilization of the electrolyte layer as necessary, sealing is performed using a main seal material around the dye-sensitized solar cell. For sealing, a thermoplastic resin, a photocurable resin, glass frit, or the like can be used as a sealing material.

Examples will be specifically shown below, but the present invention is not limited to the following examples. The part in a present Example represents a weight part.

Example 1
Preparation of current collector on transparent conductive film on transparent substrate Using PEX film with ITO film using stainless steel mesh screen (# 400) patterned with conductive paste REXALPHA RA FS 015 (Toyo Ink Manufacturing Co., Ltd.) It was obtained by heating to 140 ° C. for 1 hour to form a dry film.

Preparation of protective film made of fluoropolymer compound Fluoropolymer compound Seiffel 2662 (manufactured by Shin-Etsu Chemical Co., Ltd.) A transparent electrode using a stainless steel mesh screen (# 400) with a pattern that completely covers the current collector and its periphery It was obtained by coating on the current collector on the substrate and heating to 150 ° C. for 1 hour to form a dry film.

Preparation of a protective film comprising a cured film of a photopolymerizable composition 26.05 parts hydrogenated polybutadiene diacrylate TEAI-1000 (manufactured by Nippon Soda Co., Ltd.), 18.12 parts hydrogenated polybutadiene diacrylate SPBDA-S30 (Osaka Organic Chemical Industry) Co., Ltd.), polyisobutylene TETRAX 3T 6.59 parts (manufactured by Nippon Oil Corporation), isobornyl acrylate IBXA 35.48 parts (manufactured by Kyoeisha Chemical Co., Ltd.), hydrophobic silica R974 10 parts (Japan) Aerosil Co., Ltd.) and Irgacure 184 3.75 parts (manufactured by Ciba Specialty Chemicals Co., Ltd.) were kneaded with a ceramic three roll adjusted to 100 ° C. to obtain the desired photopolymerization composition. This is applied to the protective film made of fluoropolymer compound by using a stainless steel mesh screen (# 400) used to apply the fluoropolymer compound to the protective film made of fluoropolymer compound, and the ultraviolet curing device made by Toshiba. The film was cured by applying an energy of 800 mJ / cm ² with a system equipped with a TOSCURE 120W ultra high pressure mercury lamp. The surface of the film at this time was not sticky.

Next, UV ozone treatment was performed at a temperature of 140 ° C. for 15 minutes using a UV ozone treatment apparatus (UV and OZONE dry stripper model UV-300) manufactured by Samco.

Preparation of porous semiconductor layer Preparation of metal oxide semiconductor paste Mixing 8 parts of titanium acetylacetonate (Ti = O (acac) ₂ ) with 45 parts of 1-octanol, and titanium oxide P-25 (average particle) manufactured by Nippon Aerosil Co., Ltd. 45 parts (diameter 24 nm) was added, mixed with zirconia beads, dispersed using a paint shaker, and further 2 parts of ethylcellulose (N-200 manufactured by Hercules Co.) was dissolved and kneaded to obtain a metal oxide semiconductor paste.

  This paste was applied to the above-mentioned UV ozone-treated transparent electrode substrate using a stainless steel mesh screen (# 200) formed with a pattern designed so as not to overlap the current collector and its protective film, and 140 ° C. for 1 hour. The semiconductor porous layer was formed by heating and forming a dry film.

Adsorption of sensitizing dye Dissolve 5 × 10 ^-4 M sensitizing dye (Nex 719 manufactured by Pexel Technologies) and 1.0 × 10 ^-3 M additive chenodeoxycholic acid in a 1: 1 mixture of t-butyl alcohol and acetonitrile. Further, insoluble matter was removed with a membrane filter. The electrode sheet is immersed in this dye solution and left at 40 ° C. for 1 hour. The colored electrode surface was washed with the solvent used and then dried to obtain an electrode sheet having a sensitizing dye adsorbed on the semiconductor porous layer.

Preparation of electrolyte solution An electrolyte solution was obtained according to the following formulation.
Solvent 3-methoxyacetonitrile LiI 0.1M
I ₂ 0.05M
1-propyl-2,3-dimethylimidazolium iodide 0.6M

Assembling the dye-sensitized solar cell A test sample of the dye-sensitized solar cell was assembled as shown in FIG.
For the counter electrode, an ITO film is used as a conductive layer on the substrate, and a protective film made of a fluoropolymer compound covering the current collector and the current collector is formed on the ITO film by the same formation method as before. . As the resin film spacer, a 50 μm thick “High Milan” film manufactured by Mitsui DuPont Polychemical Co., Ltd. was used.

  The prepared dye-sensitized solar cell was placed in a constant temperature environment of 85 ° C., and after 720 hours, the current collecting wire and the weekly electric wire protective film were evaluated. As a result, there was no electrolyte permeation and the protective film was collected due to floating off. It was proved to be an excellent protective film with no electric wire dissolution by electrolyte.

Example 2
The blending ratio of the photopolymerizable composition was 26.05 parts of hydrogenated polybutadiene diacrylate TEAI-1000 (manufactured by Nippon Soda Co., Ltd.), 13.71 parts of hydrogenated polybutadiene diacrylate SPBDA-S30 (manufactured by Osaka Organic Chemical Industry Co., Ltd.) ), 11 parts of polyisobutylene TETRAX 3T (manufactured by Nippon Oil Corporation), 35.48 parts of isobornyl acrylate IBXA (manufactured by Kyoeisha Chemical Co., Ltd.), 10 parts of hydrophobic silica R974 (manufactured by Nippon Aerosil Co., Ltd.) , Irgacure 184 3.75 parts (manufactured by Ciba Specialty Chemicals Co., Ltd.) were used to prepare an electrode sheet in the same manner as in Example 1. Next, at the stage of producing the dye-sensitized solar cell, the adhesiveness on the surface of the film did not disappear, and the counter electrode was stuck at the stage of sealing with the main sealing material, and the film was broken.

Comparative Example 1
An electrode sheet was prepared in the same manner as in Example 1 except that a protective film was not formed with a photopolymerizable compound, a dye-sensitized solar cell was prepared, and placed in a constant temperature environment of 85 ° C. When the membrane was evaluated, the electrolyte permeated from the protective membrane and the current collector was dissolved in 1 hour, so a long-term test could not be performed.

Comparative Example 2
A photoelectrode was prepared in the same manner as in Example 1 except that UV ozone treatment was not performed, a dye-sensitized solar cell was prepared, placed in a constant temperature environment of 85 ° C., and after 720 hours, a current collector and a weekly wire protective film As a result, it was determined that the protective film was peeled off and was not practical. The reason why the partial peeling occurred was determined to be due to the residual organic matter due to the cleaning effect at the interface between the substrate and the protective film.

Comparative Example 3
A photoelectrode was prepared in the same manner as in Example 1 except that a protective film made of a fluoropolymer compound was not prepared, a dye-sensitized solar cell was prepared, and placed in a constant temperature environment of 85 ° C. As a result, the electrolyte permeated from the protective film, and the current collector was dissolved in 24 hours, so a long-term test could not be performed.

Comparative Example 4
The surface of the coating disappears at the stage of creating a photoelectrode and a dye-sensitized solar cell in the same manner as in Example 1 except that the protective film is not made with the photopolymerizable composition and UV ozone treatment is not performed. Without being able to be evaluated, it was stuck to the counter electrode at the stage of sealing with the main sealing material, and the film was destroyed.

  According to the present invention, it is possible to provide a current collector that is not affected at all by the electrolyte even under severe storage conditions at high temperatures. Although the protective film has a multi-layer structure for each function, it can be produced by a printing method that allows easy copying of a large number of sheets. Therefore, it can be used for the development of solar cells for new applications.

1. 1. Transparent substrate 2. Transparent conductive layer 3. Metal collector wire 4. Protective film made of fluoropolymer compound 5. Protective film comprising a cured film of the photopolymerizable composition Electrolyte 7. Main seal material8. 8. Semiconductor porous layer adsorbed with dye End seal material 10. Substrate 11. Conductive layer

Claims (8)

An electrode sheet having a semiconductor porous layer and a metal collector wire on the transparent conductive layer of the transparent substrate having a transparent conductive layer, and a protective film made of a fluoropolymer compound is provided on the metal collector wire, Further, an electrode sheet in which the protective film is coated with a film obtained by curing the photopolymerizable composition. The electrode sheet according to claim 1, wherein the fluoropolymer compound includes a fluorinated polyether skeleton and a silicon skeleton. The electrode sheet according to claim 1 or 2, wherein the photopolymerizable composition comprises polyalkene acrylate, polyalkene, photopolymerizable initiator, extender pigment, and monofunctional monomer. The electrode sheet according to any one of claims 1 to 3, wherein the polyalkene acrylate is a polybutadiene having a (meth) acryl group at a terminal and having a hydrogenated main skeleton. The electrode sheet according to any one of claims 1 to 4, wherein the polyalkene is less than 20 parts by weight with respect to 100 parts by weight of the polyalkene acrylate. 6. The electrode sheet according to claim 1, wherein the transparent substrate is a resin substrate. A dye-sensitized solar cell in which the electrode sheet according to any one of claims 1 to 6 and a counter electrode are arranged to face each other with an electrolyte, and the sensitizing dye is adsorbed to the semiconductor porous layer of the electrode sheet. Dye-sensitized solar cell. It is a manufacturing method of the electrode sheet in any one of Claims 1-6,
A step of providing a protective film made of a fluoropolymer compound on a metal collector wire, and further covering the protective film with a film obtained by curing the photopolymerizable composition;
The manufacturing method of an electrode sheet including the process 2 which forms a semiconductor porous layer on the said transparent conductive layer, and the process 3 which performs UV ozone treatment.

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