JP2009231203A - Sealer for dye-sensitized solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealer for a dye-sensitized solar cell, having a high working efficiency, and preventing leakage of an electrolyte by satisfying characteristics for a sealer such as gas barrier characteristics, solvent resistance, and adhesion characteristics. <P>SOLUTION: The sealer for the dye-sensitized solar cell includes: an inner frame 10 coming in contact with an electrolyte 5; and an outer frame 7 arranged on the outside of the inner frame 10, and the outer frame 7 and the inner frame 10 are composed of frame materials 8, 11 having gas barrier properties and adherent coating films 9, 12 formed on the surfaces coming in contact with two electrolyte substrates 13, 14 of the frame materials, the adherent coating film 9 of the outer frame is composed of a resin composition containing following (X) as an essential ingredient, and the adherent coating film 12 of the inner frame is composed of resin composition containing following (Y) as an essential ingredient and has higher solvent resistance than the adherent coating film 9 of the outer from. The (X) is a fluorine compound. The (Y) is a fluorine compound different from the (X). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sealing material for a dye-sensitized solar cell, and more specifically, is provided between electrode substrates of a dye-sensitized solar cell and seals an electrolytic solution in the dye-sensitized solar cell. It is related with the sealing material for dye-sensitized solar cells for this.

  The dye-sensitized solar cell announced by Gretzell et al. In 1991 operates by a mechanism different from that of a silicon semiconductor pn junction solar cell and requires no capital investment such as CVD (Chemical Vapor Deposition). Has the advantage of being cheap. This solar cell is also called a wet solar cell because an electrolyte is sealed inside. Specifically, the dye-sensitized solar cell has a structure as shown in FIG. That is, in FIG. 5, transparent conductive films 2 and 2 'are formed on the inner surfaces of the transparent substrates 1 and 1' facing each other. The upper transparent substrate 1 'and the transparent conductive film 2' serve as an electrode substrate that serves as an anode. On the other hand, in the transparent substrate 1 and the transparent conductive film 2 on the lower side, a porous film 3 is formed on the transparent conductive film 2 by uniformly applying and heating semiconductor particles such as titanium oxide. A sensitizing dye 4 that can efficiently absorb sunlight such as a ruthenium complex is adsorbed on the film 3. What combined these 1-4 becomes the electrode substrate used as a cathode. In the conventional dye-sensitized solar cell, the conductive film sides of the two electrode substrates are opposed to each other as shown in the figure, and bonded through a coating material 17 (main seal). The electrolyte solution 15 is injected into a substantially sealed space formed by the sealing material 17 and then the opening or hole for injecting the electrolyte solution is closed with a sealing material (end seal, not shown) or the like. It is configured.

  The mechanism by which the conventional dye-sensitized solar cell of FIG. 5 generates electricity is as follows. That is, when light strikes the transparent substrate 1 on the cathode side, the sensitizing dye 4 absorbs light and emits electrons. The electrons move to the porous film 3 made of semiconductor particles and are transmitted to the transparent conductive film 2 (electrode). Then, the electrons move to the transparent conductive film 2 ′ (electrode) on the anode side, whereby ions in the electrolytic solution 15 are reduced. The reduced ions move through the electrolytic solution 15 and are oxidized again on the sensitizing dye 4 on the cathode side. By repeating this, electricity is generated.

  As described above, the dye-sensitized solar cell requires an electrolyte such as an electrolytic solution for transferring electrons. Examples of the electrolyte include a gel electrolyte and a solid electrolyte. From the viewpoint of power generation efficiency, an electrolyte solution 15 that is a liquid is often used as shown in FIG. As the electrolytic solution 15, an iodine solution, a bromine solution, and a transition metal complex solution that transports unbound electrons are preferably used, and an organic solvent such as acetonitrile is used for these solutions.

  In FIG. 5, the sealing material 17 not only functions as a spacer for forming a space for enclosing the electrolyte solution between the two electrode substrates, but also prevents the electrolyte solution from leaking from the battery. The function as a sealing material is also required. As such a sealing material, a liquid curable resin such as an epoxy resin or a silicone resin is used (see Patent Document 1). However, the electrolytic solution is liable to corrode these resins, and has a drawback that the electrolytic solution leaks due to swelling or deterioration due to contact with the electrolytic solution for a long time.

On the other hand, as the sealing material 17, a material using a polyisobutylene-based, isoprene-based or methacrylate-based elastic material as a forming material has been proposed. By using such an elastic material, the compression set resistance against the weight of the electrode substrate and the low modulus following the deformation of the electrode substrate can be obtained, so that a good sealing property can be obtained (Patent Document) 2-5).
JP 2000-30767 A JP 2004-95248 A JP 2004-311036 A JP 2005-302564 A JP 2006-185646 A

  By the way, the functions shown in the following items (1) to (5) are regarded as important for sealing the electrolyte solution of the dye-sensitized solar cell. (1) Solvent resistance that does not allow electrolyte solution (eg acetonitrile) to leak out, (2) Gas barrier property that does not leak gas generated from electrolyte solution (volatile solvent, sublimated iodine, etc.), (3) Electrode substrate Self-adhesiveness that does not create a gap with (4), (4) room temperature curability in which the sealing material is cured at room temperature, and (5) workability that enables uniform sealing.

  The reason why the above items (1) and (2) are regarded as important is to prevent deterioration of power generation characteristics due to leakage of electrolyte solution or volatile gas of the electrolyte solution. The reason why the item (3) is regarded as important is to prevent power generation characteristics from being deteriorated due to leakage and intrusion from the air gap. The reason why the above item (4) is regarded as important is that the power generation characteristics of the electrode to which the dye having low thermal stability is adsorbed are markedly reduced when a high temperature treatment is performed during curing. Further, in the case of a UV curable resin, not only does UV light adversely affect the pigment and the power generation characteristics of the electrode are deteriorated, but also a large facility is required. The reason why the above item (5) is regarded as important is that work efficiency and productivity are poor because uniform application of the thickness of the sealing material is difficult.

  The conventional sealing material and the proposed sealing material cannot sufficiently satisfy all the items (1) to (5). In particular, if the encapsulant does not satisfy the characteristics of solvent resistance, gas barrier property, and adhesiveness, the electrolyte solution leaks, and thus a highly reliable dye-sensitized solar cell cannot be formed. Moreover, since the item (5) is a problem in actual production, there is an influence of materials used, conditions of use, etc., and it is difficult to achieve a desired result. In particular, since the main seal by application is difficult to provide a multilayer structure and to control the thickness of the sealing coating film uniformly, excess or deficiency of the sealing material forming material on the application surface, generation of bubbles, etc. As a result of this phenomenon, it is difficult to obtain sufficient adhesion reliability. In addition, there is a method using a squeegee method (making a step with a mending tape or the like and stretching the resin with a glass rod or the like) or a dispenser, but these operations are complicated and inferior in productivity. However, since mass production cannot be expected without improving productivity and workability, improvement and improvement of item (5) above are now envied.

  The present invention has been made in view of such circumstances, and has excellent workability and a dye that prevents leakage of the electrolyte by satisfying the characteristics required of a sealing material such as gas barrier properties, solvent resistance, and adhesive strength. The purpose is to provide a sealing material for a sensitized solar cell.

In order to achieve the above object, in the dye-sensitized solar cell, the present invention is interposed between the two electrode substrates to form a space for encapsulating the electrolyte between the two electrode substrates facing each other. A sealing material that includes an inner frame that is in contact with the electrolytic solution and an outer frame that is provided outside the sealing member. The outer frame and the inner frame have a gas barrier property, and the frame. An adhesive coating film formed on the surface of the material in contact with the two electrode substrates, the adhesive coating film of the outer frame body is made of a resin composition having the following (X) as an essential component, A sealing material for a dye-sensitized solar cell, in which the adhesive coating film of the inner frame is composed of a resin composition having the following (Y) as an essential component and is more solvent resistant than the adhesive coating film of the outer frame. The gist.
(X) Fluorine compound.
(Y) A fluorine compound different from the above (X).

  That is, the present inventors are bound by the technical common sense that a sealing material (coating film) is formed by coating a sealing material material on an electrode substrate in order to improve the production workability of a dye-sensitized solar cell. First, research was repeated based on the idea of preparing a frame body in advance using a sealing material and then sealing the frame body using the frame body. In the course of the research, the required physical properties are different on the electrolyte side and the outside side of the encapsulant, so in order to obtain a more reliable dye-sensitized solar cell with one frame We thought that there was a certain limit to correspondence. Therefore, the sealing material has a two-frame structure of an inner frame body and an outer frame body, and the constitution of the resin composition for an adhesive coating film used for the inner frame body and the outer frame body is changed to the component (X), (Y ) By using it separately from the component, it is possible to finely cope with the different physical properties required for the electrolyte side and the outside side of the sealing material, thereby not only improving workability but also adhesiveness, gas barrier properties, resistance The inventors have found that the properties required for a sealing material called solvent can be satisfied, and have reached the present invention.

  As described above, in the dye-sensitized solar cell, the present invention is a sealing interposed between the two electrode substrates in order to form a space for enclosing the electrolyte between the two electrode substrates facing each other. An outer frame provided on the outer side of the inner frame in contact with the electrolytic solution, the outer frame and the inner frame having a gas barrier property, and the above frame material An adhesive coating film formed on a surface in contact with two electrode substrates, and the adhesive coating film of the outer frame body is made of a resin composition containing a fluorine compound (X) as an essential component, and the inner frame The body-adhesive coating film is made of a resin composition containing a fluorine compound (Y) different from the above (X) as an essential component, and has a higher solvent resistance than the adhesive coating film of the outer frame body. Sealing material. That is, according to the present invention, the frame body (sealing material) has a two-frame structure of the inner frame body and the outer frame body, and the adhesive coating film of the inner frame body is more than the adhesive coating film of the outer frame body. Because it is made of a resin composition containing a fluorine compound that is rich in solvent resistance as an essential component, it not only excels in workability, but also has characteristics required for sealing materials such as solvent resistance, gas barrier properties, and adhesiveness. Can be satisfied, and leakage of the electrolyte can be prevented. Further, since the sealing material is formed of the frame material and the adhesive coating film according to the present invention, it is unnecessary to apply the liquid sealing material to the electrode substrate, and the frame body is used for both substrates at the time of sealing. It is sufficient to intervene between them. This eliminates the need for complicated operations such as coating using a sealant material dispenser, selection of coating solvents, and management of coating conditions at the production site, greatly improving production efficiency. It becomes like this.

  Moreover, when the adhesive coating film of the said outer side frame body and an inner side frame body consists of a room temperature curable resin composition, it will come to prevent the pigment deterioration by UV light irradiation or heat processing.

  Furthermore, when the frame material having gas barrier properties is made of a resin composition containing ethylene-vinyl alcohol copolymer (EvOH) as a main component, the solvent resistance and gas barrier properties are further improved.

And if the resin composition which has said (X) as an essential component is a resin composition which has the following (a)-(c) as a main component, it will be excellent by the solvent resistance of an outer side frame, and gas barrier property. Become.
(A) A fluoropolyether compound having at least two hydroxyl groups in one molecule and having a perfluoropolyether structure in the main chain of the molecule.
(B) Isocyanate compound.
(C) Reaction catalyst.

  When the component (Y) is a fluoropolyether compound having at least two hydrolyzable groups in one molecule and having a perfluoropolyether structure in the main chain of the molecule, It becomes more excellent in the solvent resistance and gas barrier properties of the body.

  Next, embodiments of the present invention will be described in detail.

  The encapsulant for a dye-sensitized solar cell of the present invention is preliminarily made of an encapsulant material as illustrated in the plan view of FIG. 1A and the AA ′ cross-sectional view of FIG. 1B. The outer frame body 7 and the inner frame body 10 are formed of two frames. The outer frame body 7 and the inner frame body 10 are for forming a space in which the electrolytic solution 5 is sealed between the two electrode substrates 13 and 14 facing each other. 14 is interposed.

  Here, the electrolytic solution 5 is a component that acts as a charge transfer medium, and includes a highly polar organic solvent and a redox agent. As the high-polarity organic solvent, those known as reaction media in electrochemical reactions are desirable, and among them, those having a high dielectric constant and capable of dissolving salts as used in lithium ion batteries are preferred. Examples of such solvents include cyclic carbonates such as propylene carbonate, acyclic carbonates such as dimethyl carbonate, ethers such as dioxane, tetrahydrofuran, 2-methyltetrahydrofuran and ethylene glycol dialkyl ether, nitriles such as acetonitrile, Examples include sulfoxides such as dimethyl sulfoxide, aprotic positive solvents such as dimethyl sulfoxide, lactones such as γ-butyrolactone, amides such as dimethylformamide, and heterocyclic rings such as 3-methyl-2-oxazolinone. It is done. These may be used alone or in combination of two or more.

  As the redox agent, iodine and a metal iodine compound are preferable. Examples of the metal iodine compound include lithium iodide, sodium iodide, potassium iodide, cesium iodide and the like. Examples of the redox agent combined with iodine include not only the above metal iodine compounds but also iodide salts of quaternary pyridinium salts and quaternary imidazolium salts. Furthermore, hetero compounds such as amines and thiols can also be used as reducing aids, and redox catalysts such as ferrocyanates can be added.

  The electrode substrate 13 (cathode side) in contact with both frame bodies (sealing material) of the present invention comprises a conductive film 2a, a porous film 3a, and a sensitizing dye 4a on one side of the base substrate 1a. The electrode substrate 14 (anode side) includes a conductive film 2b on one side of the base substrate 1b.

  The base substrates 1a and 1b according to the present invention are not particularly limited as long as they have a substrate shape, and examples thereof include a glass substrate and a resin substrate. Examples of the glass substrate include those made of a hard substance mainly composed of silicate. Examples of the resin substrate include those formed from a resin composition containing a synthetic resin as a main component. Examples of the synthetic resin include acrylic resin, polycarbonate, polystyrene, polyethylene terephthalate, polyethylene naphthalate (PEN), polyvinyl alcohol (PVA), and the like. These may be used alone or in combination of two or more. A glass substrate is preferable in that it can sufficiently exhibit the adhesiveness of the sealing material. In addition, in order for the sensitizing dye to absorb light, at least one of the base substrates 1a and 1b may be any material and shape that easily transmits light, and is preferably transparent.

  In addition, in this invention, a main component means the component which occupies the majority of the whole, and is the meaning including the case where the whole consists only of a main component. In the base substrate, a reinforcing material or the like can be contained as necessary in addition to the main component.

  The conductive films 2a and 2b are transparent as long as at least one of the conductive films 2a and 2b easily transmits light, so that the sensitizing dye absorbs light as in the base substrate. It is preferable. As the transparent conductive film, the smaller the sheet resistance, the better. For example, indium-tin composite oxide (ITO), tin oxide doped with fluorine (FTO), tin oxide doped with antimony (ATO), tin oxide Etc. are used. These may be used alone or in combination of two or more. Further, since the conductive film 2b on the anode side is in direct contact with the electrolytic solution, it is also preferable to use a highly corrosion-resistant conductive material such as platinum (Pt) or titanium (Ti).

  The porous film 3a is obtained by sintering semiconductor particles such as titanium oxide. Examples of the semiconductor particles include titanium oxide, zinc oxide, tungsten oxide, niobium oxide, strontium titanate, and tin oxide. Among these, titanium oxide is preferable. These may be used alone or in combination of two or more. The porous membrane 3a preferably has a large surface area so that a large amount of the sensitizing dye 4a can be adsorbed.

  The sensitizing dye 4a adsorbed on the porous film 3a exhibits a sensitizing action. For example, xanthene dyes, cyanine dyes, basic dyes, other azo dyes, porphyrin compounds, phthalocyanine compounds, coumarin compounds , Ruthenium complexes, bipyridine complexes, terpyridine complexes, anthraquinone dyes, polycyclic quinone dyes, squarylium dyes, and the like. These may be used alone or in combination of two or more.

  Next, a sealing material (frame body) interposed between the two electrode substrates will be described.

  As illustrated in FIG. 1, the frame body that is the sealing material of the present invention is configured by a two-frame structure of a ring-shaped outer frame body 7 and a ring-shaped inner frame body 10 having a smaller diameter. In addition, the outer frame body 7 and the inner frame body 10 are configured by forming a material having a rectangular cross section into a ring shape. The shape is not limited to the rectangle, and may be a circle or the like. There may be a gap between the two frames 7 and 10, but it is preferable that there is no gap in terms of solvent resistance and gas barrier properties. Hereinafter, the outer frame body 7 and the inner frame body 10 will be described separately.

<Outer frame>
The outer frame 7 is composed of a frame member 8 and an adhesive coating film 9 formed on at least the surfaces (upper and lower surfaces) of the frame member in contact with the electrode substrate. From the viewpoint of productivity and workability of the dye-sensitized solar cell, it is preferable that the adhesive coating film 9 is coated on the entire surface of the frame member 8 as shown in FIG. The case where the adhesive coating film 9 is coated only on the surface of the material 8 in contact with the electrode substrate may be used.

<Frame material: For outer frame>
The frame material 8 of the outer frame body 7 is formed in a ring shape by casting, embossing, injection molding or the like using a mold in advance using a frame material forming material. It is preferable that the material is formed into a resin film and is cut into an arbitrary shape such as a circle. The frame material 8 is not limited to the ring shape, and is not particularly limited as long as it has a frame shape. However, the frame material 8 has a frame shape such as a circular frame or a square frame having self-retaining properties. Preferably used. And it is preferable that such a frame material has the hardness which can be handled.

  The material for forming the frame material 8 is made of a material having a gas barrier property against a volatile gas from the electrolytic solution, and is preferably composed of a resin composition for a frame material mainly composed of a resin having a gas barrier property. . Examples of the resin having gas barrier properties include ethylene-vinyl alcohol copolymer (EvOH), polyvinylidene chloride (PVDC), polyvinyl alcohol (PVA), polychlorinated alcohol, nylon, polyacrylonitrile, polyethylene, polyethylene terephthalate, and the like. These may be used alone or in combination of two or more. Among these, EvOH is particularly preferable. The molecular weight of the gas barrier resin is particularly preferably in the range of 1500 to 20000.

  The resin composition for a frame material mainly composed of a resin having a gas barrier property as described above may contain a resin that does not have a gas barrier property in some cases, but the resin having the gas barrier property is a resin for a frame material. It is preferable to occupy a proportion of 40% by volume or more of the entire composition. In the present invention, having a gas barrier property means that the dye-sensitized solar cell produced by using the sealing material of the present invention is heat-treated at 85 ° C. for 20 hours, and then the dye-sensitized solar cell. It means that no bubbles are generated inside.

Further, the frame material 8 is formed by forming the forming material by a method such as molding and then depositing a silicon (Si) compound or an aluminum (Al) compound on the surface of the frame material. It is preferable in terms of further improvement. Examples of the Si compound include Si, SiO, SiO ₂ , SiN, and SiAlO. Examples of the Al compound include Al, Al ₂ O ₃ , AlO, SiAlO, and the like. These may be used alone or in combination of two or more. Among these, SiO ₂ is particularly preferable. In the present invention, the silicon compound is intended to include Si alone, and the aluminum compound is intended to include Al alone. In addition to the silicon compound or the aluminum compound, a metal such as gold, platinum, silver, copper, zinc, or nickel may be used for vapor deposition.

  The vapor deposition method is not particularly limited, and examples thereof include a sputtering method and an electrodeposition method. Among these, the sputtering method is particularly preferable.

<Adhesive coating film: for outer frame>
The adhesive coating film 9 is formed on the surface of the frame material 8 in contact with the electrode substrate, and the outer frame body 7 is formed from the adhesive coating film 9 and the frame material 8. Simultaneously with the formation of the adhesive coating film 9 by curing or the like, the outer frame 7 and the electrode substrate are bonded and integrated by the adhesive force of the adhesive coating film 9. And the said adhesive coating film 9 consists of a resin composition which has a fluorine compound (X) as an essential component, and it is preferable that it is a room temperature curable resin composition. This is because, when it can be cured at room temperature, UV light irradiation and heat treatment are not necessary, and pigment deterioration can be prevented. Examples of the resin composition containing the fluorine compound (X) as an essential component include a fluoropolyether having at least two hydroxyl groups in one molecule and a perfluoropolyether structure in the main chain of the molecule. Examples thereof include a resin composition (composition I) containing the compound (a), an isocyanate compound (b) and a reaction catalyst (c) as main components. Here, in the present invention, the essential component refers to an optional component that is included in an optional component.

  The composition I will be described. As the fluoropolyether compound (a) having at least two hydroxyl groups in one molecule and having a perfluoropolyether structure in the main chain of the molecule, those having a molecular weight of 2000 to 10,000 are preferable. It is because the tendency to be inferior to solvent resistance is seen as it is less than the said lower limit, and the tendency to be inferior to adhesiveness is seen when it exceeds the said upper limit.

  More preferably, what is shown in following General formula (1) is mention | raise | lifted.

  The isocyanate compound (b) used together with the component a is not particularly limited, but an organic isocyanate compound having at least two isocyanate groups in one molecule is preferably used.

  Specific examples of the isocyanate compound (b) include 4,4′-diphenylmethane diisocyanate (MDI), 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2, 6-TDI), 3,3′-vitrylene-4,4′-diisocyanate, 3,3′-dimethyldiphenylmethane-4,4′-diisocyanate, 2,4-tolylene diisocyanate uretidinedione (2,4-TDI) Dimer), 1,5-naphthylene diisocyanate, metaphenylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI), carbodiimide-modified MDI, orthotoluidine diisocyanate, xylene diiso Examples thereof include diisocyanates such as anate, paraphenylene diisocyanate and lysine diisocyanate methyl ester, triisocyanates such as triphenylmethane-4,4 ′, 4 ″ -triisocyanate, and polymeric MDI. These may be used alone or in combination of two or more. Used.

  The NCO / OH index (number of isocyanate groups / number of hydroxyl groups × 100) of the specific fluoropolyether compound (a) and the isocyanate compound (b) is preferably set to 100 to 300, particularly preferably 150 ~ 250. That is, if the amount is less than the above lower limit value, the adhesive force tends to deteriorate because crosslinking is not sufficiently performed. Conversely, if the value exceeds the upper limit value, unreacted isocyanate groups are likely to be generated, and the curing rate is reduced. There is a tendency to lead to delays.

  The reaction catalyst (c) used together with the components a and b is not particularly limited as long as it can exhibit a catalytic function for the crosslinking reaction, but a urethanization reaction catalyst is preferable. Examples of the urethanization reaction catalyst include amine compounds such as triethylenediamine, organometallic compounds such as organotin compounds, 1,8-diazabicyclo (5,4,0) -undecene-7 (DBU), 1,5- Examples thereof include diazabicyclo (4,3,0) -nonene-5 (DBN) and diazabicycloamine salts. In addition, the compounding quantity of the said reaction catalyst (c) is set to the range of 0.01-5 parts with respect to 100 weight part (henceforth "part") of the said specific fluoropolyether compound (a). It is preferable.

  All or part of the fluoropolyether compound (a) having the above characteristics and all or part of the isocyanate compound (b) may be used as a prepolymer reacted in advance as necessary.

  In this prepolymer, for example, the fluoropolyether compound (a) having the above characteristics and the isocyanate compound (b) are placed in a separable flask or the like, and mixed partly or entirely with a stirring blade at 80 ° C. for several hours. It is obtained by reacting. By prepolymerization, it is possible to suppress the generation of bubbles in the sealing material and to improve the workability when applying the sealing material.

  Next, the inner frame 10 will be described.

<Inner frame>
As shown in FIG. 1, the inner frame 10 includes a frame member 11 and an adhesive coating film 12 formed on at least the surfaces (upper and lower surfaces) of the frame member that are in contact with the electrode substrate. From the viewpoint of productivity and workability of the dye-sensitized solar cell, as shown in FIG. 1, it is preferable that the adhesive coating film 12 is coated on the entire surface of the frame material 11. The case where the adhesive coating film 12 is coated only on the surface in contact with the electrode substrate may be used.

<Frame material: For inner frame>
The frame material 11 of the inner frame 10 is the same as the outer frame 8 described above, and is formed into a ring shape or the like using the same frame material. In other words, the frame material forming material is formed in advance by casting using a mold, embossing, injection molding, etc., and the frame material forming material is formed into a resin film, and this is arbitrarily formed into a circular shape. It is preferably formed by cutting into a shape.

  The material for forming the frame member 11 is made of a material having a gas barrier property against a volatile gas from the electrolytic solution, and is preferably composed of a resin composition for a frame member whose main component is a resin having a gas barrier property. . Examples of the resin having gas barrier properties include ethylene-vinyl alcohol copolymer (EvOH), polyvinylidene chloride (PVDC), polyvinyl alcohol (PVA), polychlorinated alcohol, nylon, polyacrylonitrile, polyethylene and polyethylene terephthalate. These may be used alone or in combination of two or more. Among these, EvOH is particularly preferable as in the case of the outer frame 8. The molecular weight of the resin having gas barrier properties is particularly preferably in the range of 1500 to 20000. In addition, it may be the same as or different from the material for forming the frame member 8 of the outer frame.

Further, as in the case of the outer frame 8, the frame member 11 is formed by forming the forming material by a method such as molding, and then deposits a silicon (Si) compound or an aluminum (Al) compound on the surface of the frame member. Is preferable from the viewpoint of improving gas barrier properties. Examples of the Si compound include Si, SiO, SiO ₂ , SiN, and SiAlO. Examples of the Al compound include Al, Al ₂ O ₃ , AlO, SiAlO, and the like. These may be used alone or in combination of two or more. Among these, SiO ₂ is particularly preferable.

  The vapor deposition method is not particularly limited, and as in the case of the outer frame 8, for example, a sputtering method, an electrodeposition method, and the like can be mentioned, and among these, the sputtering method is particularly preferable.

<Adhesive coating film: for inner frame>
The adhesive coating film 12 is formed on the surface of the frame material 11 in contact with the electrode substrate, and the inner frame body 10 is formed from the adhesive coating film 12 and the frame material 11. Simultaneously with the formation of the adhesive coating film 12 by curing or the like, the inner frame body 10 and the electrode substrate are bonded and integrated by the adhesive force of the adhesive coating film 12. And the said adhesive coating film 12 consists of a resin composition which has as an essential component the fluorine compound (Y) different from the fluorine compound (X) used for the adhesive coating film of the said outer side frame, The said outer side frame 7 The resin composition for the adhesive coating film 9 is made of a resin composition that is richer in solvent resistance than the resin composition for the adhesive coating film 9. The resin composition containing the component (Y) as an essential component is preferably a room temperature curable resin composition. This is because, when it can be cured at room temperature, UV light irradiation and heat treatment are not necessary, and pigment deterioration can be prevented. Examples of the room temperature curable resin composition include a one-component RTV (Room Temperature Vulcanizing) or a two-component RTV fluorine-based resin composition that is cured into an elastomer at room temperature by contact with moisture in the air. Can be given.

  Examples of the one-component RTV fluorine-based resin composition include deoxime-type, dealcohol-free type, deacetic acid-type, deamidated-type, and deacetone-type, and the two-component RTV fluorine-based resin composition includes Examples thereof include dealcohol-type, dehydroxylamine-type, and dehydrogenation-type. Among these, a one-component type is preferable from the viewpoint of workability, and a deoxime type is preferable from the viewpoint of adhesion and odor.

  Examples of the fluorine compound (Y) include fluoropolyether compounds having at least two hydrolyzable groups or hydroxyl groups in one molecule and having a perfluoropolyether structure in the main chain of the molecule. It is done. And it is preferable to have this specific fluoropolyether compound as a main component.

  Examples of the hydrolyzable group of the specific fluoropolyether compound include an oxime group such as a methylethylketoxime group and a dimethylketoxime group, an alkoxy group such as a methoxy group, an ethoxy group, and a propoxy group, and an isopropenoxy group. Examples thereof include an alkenyloxy group and a trimethoxysilylpropyl group. These may be used alone or in combination of two or more. Among these, an oxime group is preferable from the viewpoint of adhesiveness and odor.

  And as said specific fluoro polyether compound, Preferably, what is shown to following General formula (2) is mention | raise | lifted.

  Moreover, you may contain a catalyst with the said (Y) component in the said resin composition for adhesive coating films. This catalyst is a component for accelerating the curing reaction of the resin composition containing (Y) as an essential component. Examples of the catalyst include organic titanium compounds such as tetraisopropoxy titanium, tetra-t-butoxy titanium, titanium di (isopropoxy) bis (ethylacetoacetate), titanium di (isopropoxy) bis (acetylacetonate); Organotin compounds such as dibutyltin dilaurate, dibutyltin bisacetylacetonate, tin octylate; metal dicarboxylates such as lead dioctylate; organozirconium compounds such as zirconium tetraacetylacetonate; organoaluminum compounds such as aluminum triacetylacetonate And amines such as hydroxylamine and tributylamine. Among these, an organic titanium compound is preferable, and in order to obtain the improved adhesiveness and storage stability of the present composition, a titanate ester and a titanium chelate catalyst are particularly preferable. These may be used alone or in combination of two or more.

  The amount of the catalyst is a catalyst amount, and is usually in the range of 0.01 to 10 parts, preferably in the range of 0.05 to 7 parts, with respect to 100 parts of the (Y) component. If the blending amount is less than the above lower limit value, the curability of the present composition tends to decrease, and if it exceeds the upper limit value, the storage stability tends to deteriorate.

  In addition to the above-described components, the frame materials 8 and 11 and the adhesive coating films 9 and 12 may be made of a surfactant, a curing accelerator, a plasticizer, a filler, a curing delay, if necessary. Other additives such as an agent, a processing aid, a flame retardant, an anti-aging agent, an antioxidant, an ultraviolet absorber, a colorant, and a curing agent can be appropriately blended. These may be used alone or in combination of two or more.

《Dye-sensitized solar cell manufacturing method》
Here, the manufacturing method is demonstrated using FIGS. 1-4 about the dye-sensitized solar cell in which the sealing material of this invention is used. In addition, the dye-sensitized solar cell obtained and its manufacturing method are not limited to FIGS. 1-4, Moreover, the sealing material for dye-sensitized solar cells of this invention is also the shape shown in FIGS. It is not limited to the usage pattern.

  First, prior to the method for producing a dye-sensitized solar cell, a frame material and an adhesive coating film resin composition that constitute the sealing material (outer frame and inner frame) are prepared and produced.

<Production of frame material>
The forming materials for the frame members 8 and 11 described above are kneaded as necessary to obtain resin compositions for frame members for the outer frame and the inner frame. The frame resin compositions for the frame members 8 and 11 may be the same or different. The obtained frame resin composition is cut into an arbitrary shape such as a circular frame. Thus, the frame members 8 and 11 illustrated in FIG. 2B which is a plan view of FIG. Moreover, you may produce the frame material which vapor-deposited the silicon compound or the aluminum compound on this surface.

<Preparation of resin composition for adhesive coating film>
Next, preparation of the resin composition for an adhesive coating film will be described. First, the materials for forming the adhesive coating films 9 and 12 are kneaded using a stirring blade, a Banbury mixer, a kneading roll or the like to prepare resin compositions for the adhesive coating films, respectively. As long as the obtained resin composition for the adhesive coating film 9 for the outer frame material is richer in solvent resistance than the resin composition for the adhesive coating film 12 for the inner frame body, the preparation method is the same. May be different.

<Preparation of dye-sensitized solar cell>
The dye-sensitized solar cell according to the present invention includes the following (I) to (III) using the frame materials 8 and 11 and the resin composition for the adhesive coating films 9 and 12 obtained as described above. Manufactured via a process.

(I) Two electrode substrates and a frame material are prepared.
As shown in FIG. 1, in the electrode substrate 13 to be a cathode, a conductive film 2a is formed on one surface of a base substrate 1a, and semiconductor particles such as titanium oxide are uniformly applied on the conductive film 2a and heated. The porous film 3a is provided, and the porous film 3a is further adsorbed with a sensitizing dye 4a such as a ruthenium complex. The electrode substrate 14 serving as an anode is configured by forming a conductive film 2b on one surface of a base substrate 1b similar to the above.

  Next, at least the surfaces (upper and lower surfaces) in contact with the electrode substrate of the frame member 8 shown in FIG. 2 manufactured as described above are immersed in a liquid resin composition for the adhesive coating film 9 to obtain a resin. The composition is attached to the surface. Similarly, at least the surfaces (upper and lower surfaces) in contact with the electrode substrate of the frame member 11 are immersed in the liquid resin composition for the adhesive coating film 12 to adhere the resin composition to the surface.

  In addition, it is preferable from the viewpoint of solvent resistance and workability that the adhesive coating film is formed not only on the upper and lower surfaces of the frame material but also on the entire frame material. FIGS. 3A and 3B show a state where an adhesive coating film is formed on the entire frame member 8. In addition, you may form the said coating film by application | coating.

(II) Overlay the frame material and the electrode substrate.
As shown in FIGS. 4A and 4B, the frame material 8 in which the resin composition for the adhesive coating film 9 is attached on the electrode substrate 13, that is, the composition for the frame body 7, and the adhesive coating film. The frame material 11 to which the resin composition for 12 adheres, that is, the composition for the frame body 10 is disposed. In order to improve the adhesion to the electrode substrate 13, it is preferable to appropriately perform primer treatment on the adherend surface. And the electrode substrate 14 is made to oppose the said electrode substrate 13, and it overlaps | superposes through the frame materials 8 and 11 to which the said resin composition for adhesive coating films adhered.

(III) The electrode substrate is bonded.
In a state where the electrode substrates are overlapped as described above, the two electrode substrates are bonded using the resin composition for an adhesive coating film attached to the frame members 8 and 11. That is, the resin composition for an adhesive coating film is cured (preferably left at room temperature of 25 ° C. ± 10 ° C. for 30 to 200 minutes) with the electrode substrates stacked, and formed on the adhesive coating films 9 and 12. To do. Thereby, the frame bodies 7 and 10 which consist of the frame materials 8 and 11 and the adhesive coating films 9 and 12 are formed, and at the same time, the frame bodies 7 and 10 and the electrode substrate are bonded and integrated. And the electrolyte solution 5 is inject | poured from the injection hole 16 drilled in the said electrode board | substrate 14, and the said injection hole 16 is block | closed after that, A dye-sensitized solar cell as shown in FIG. 1 is obtained.

  Regarding the dye-sensitized solar cell, the width of the outer frame 7 is not particularly limited, but is preferably in the range of 0.5 to 5 mm, and the thickness of the outer frame 7 is not particularly limited, but is 11 to 11. It is preferable that it is 150 micrometers. More specifically, the thickness of the frame member 8 constituting the outer frame body 7 is not particularly limited, but is preferably in the range of 10 to 100 μm, and particularly preferably in the range of 20 to 50 μm. Further, the thickness of the adhesive coating 9 applied on the frame member 8 is not particularly limited, but is preferably in the range of 1 to 50 μm, and particularly preferably in the range of 1 to 5 μm.

  The width of the inner frame 10 is not particularly limited, but is preferably in the range of 0.5 to 5 mm, and the thickness of the inner frame 10 is not particularly limited, but is preferably 11 to 150 μm. More specifically, the thickness of the frame member 11 constituting the inner frame body 10 is not particularly limited, but is preferably in the range of 10 to 100 μm, and particularly preferably in the range of 20 to 50 μm. Further, the thickness of the adhesive coating 12 applied on the frame member 11 is not particularly limited, but is preferably in the range of 1 to 50 μm, and particularly preferably in the range of 1 to 5 μm.

  The outer frame and the inner frame according to the present invention are not limited to the configuration of the frame members 8 and 11 and the adhesive coating films 9 and 12 as illustrated in FIG. Other resin layers, rubber layers, and the like may be formed between the adhesive coating films 9 and 12.

  Next, examples will be described together with comparative examples. However, the present invention is not limited to these examples.

[Example 1]
<For outer frame: Preparation of resin composition for adhesive coating film>
100 parts of a linear fluoropolyether compound (manufactured by Solvay Solexis, Fluorolink D4000) having at least two hydroxyl groups in one molecule and having a perfluoropolyether structure in the main chain of the molecule; 7 parts of an isocyanate compound (manufactured by BASFINOAC polyurethane, Lupranate M20S) was previously stirred with a stirring blade at 80 ° C. for 4 hours to prepare a prepolymer. Then, 0.3 part of a urethanation reaction catalyst (Kao Corporation, KAO No. 31) was added to the prepolymer, and kneading was carried out using a stirring blade, whereby an adhesive coating film for an outer frame was obtained. A preparation composition was prepared and prepared.

<Inner frame: Preparation of resin composition for adhesive coating>
RTV fluororubber (manufactured by ThreeBond Co., Ltd.) prepared as a linear fluoropolyether compound having at least two hydrolyzable groups in one molecule and having a perfluoropolyether structure in the main chain of the molecule. ThreeBond 1119) was prepared by preparing a resin composition for an adhesive coating for an inner frame.

<Production of frame material>
In addition, a resin film (Kuraray Co., Ltd., Eval EF-F, thickness: 30 μm) made of EvOH is used as a circular frame (cross-sectional thickness: 30 μm, cross-sectional width: 1.5 mm) using a punching blade. A frame material forming an inner frame body was prepared. Also, as the frame material for the outer frame body, a material prepared in the same manner as the frame material for the inner frame body was prepared except that the size of the circular frame was changed to 34 mm in diameter.

<Production of simulated battery>
Next, using these materials, a simulated dye-sensitized solar cell was produced according to the steps described above. First, two transparent conductive glass plates (manufactured by Geomat Co., Ltd., heat-resistant transparent ITO glass, 5 cm × 5 cm × thickness 1.5 mm) are prepared. In addition, the resin composition for an adhesive coating for the outer frame is applied to the entire surface of the frame material for the outer frame, and the resin composition for the adhesive coating for the inner frame is applied to the inner frame. It apply | coated to the whole surface of the frame material for bodies. In this state, the both frame members were sandwiched between the glass substrates. Next, the resin composition for an adhesive coating film is cured (left) at room temperature (25 ° C. × 3 hours) to form an adhesive coating film, and from the coating film and the frame material by the adhesive force of the coating film. The frame body and the substrate were bonded and integrated. Next, from a hole (injection port) having a diameter of 1.5 mm previously formed on one side of the glass substrate, an electrolytic solution (solvent [γ-butyrolactone, manufactured by Wako Pure Chemical Industries, Ltd.], solute [iodine: 50 mM, LiI: 500 mM]. , T-butylpyridine: 580 mM, manufactured by Wako Pure Chemical Industries, Ltd.]) is injected in a vacuum state, and then the injection port is prepared as a 5 mm × 5 mm × 1.5 mm thick preparation with the adhesive coating resin composition applied thereto. A simulated dye-sensitized solar cell was fabricated by closing with. In addition, the width | variety of the said outer side frame and an inner side frame is about 1.5 mm, respectively, and is about 3.0 mm collectively. The thickness of the frame material constituting this frame was 30 μm, and the thickness of the adhesive coating film was 5 μm.

[Comparative Example 1]
A frame having a one-frame structure was produced using the frame material and the adhesive coating film, which are the materials for forming the inner frame in Example 1. The frame has a diameter of 34 mm and a width of about 3.0 mm. Moreover, the thickness of the frame material which comprises this frame was 30 micrometers, and the thickness of the adhesive coating film was 5 micrometers. Otherwise, a simulated dye-sensitized solar cell was produced in the same manner as in Example 1 above.

[Comparative Example 2]
A frame having a one-frame structure was produced using the frame material and the adhesive coating film, which are the materials for forming the outer frame in Example 1. The frame has a diameter of 34 mm and a width of about 3.0 mm. Moreover, the thickness of the frame material which comprises this frame was 30 micrometers, and the thickness of the adhesive coating film was 5 micrometers. Otherwise, a simulated dye-sensitized solar cell was produced in the same manner as in Example 1 above.

[Comparative Example 3]
The resin composition for an adhesive coating film of Comparative Example 1 was not used as an adhesive coating film for a frame, but was used as a sealing material composition that formed the entire sealing material by itself. That is, no frame material was used. Specifically, two transparent conductive glass plates (manufactured by Geomatek Co., Ltd., heat-resistant transparent ITO glass, 5 cm × 5 cm × thickness 1.5 mm) are prepared, and one of them is provided with the composition for sealing material. After coating in a frame shape so as to have a uniform thickness, the remaining glass substrate is overlaid on the composition for sealing material, and a substantially sealed space is formed by both glass substrates and the frame-shaped sealing material composition. Formed. Thereafter, the encapsulant composition is cured (left) at room temperature (25 ° C. × 3 hours), and the substrate and the encapsulant composition are joined. A hole (injection port) having a diameter of 1.5 mm is preliminarily formed on one side of the glass substrate. From this injection port, (solvent [γ-butyrolactone, manufactured by Wako Pure Chemical Industries, Ltd.], solute : Iodine (50 mM), LiI (500 mM), t-butylpyridine (580 mM), manufactured by Wako Pure Chemical Industries, Ltd.) in a vacuum state, and then the injection port is a glass plate of 5 mm × 5 mm × thickness 1.5 mm A simulated dye-sensitized solar cell is produced by closing the single-sided surface with the composition for sealing material applied thereto. The sealing material had a diameter of 34 mm, a width of about 3.0 mm, and a thickness of 40 μm.

[Comparative Example 4]
After the composition for sealing material of Comparative Example 3 was cured at room temperature, an EvOH aqueous solution (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., 16D) was applied to the outer peripheral surface of the frame-shaped sealing material, dried, and sealed. An EvOH layer was formed on the outer peripheral surface of the material. Other than that was carried out similarly to the comparative example 3, and produced the simulated dye-sensitized solar cell. The EvOH layer had a width of 100 μm and a thickness of 40 μm.

  The simulated dye-sensitized solar cell thus obtained was evaluated for electrolytic solution leakage prevention and workability according to the following criteria. These results are also shown in Table 1 below.

<Electrolytic solution leakage prevention>
The prepared dye-sensitized solar cell was put in a 95 ° C. heat oven and heat-treated for 1000 hours. The weight change rate due to electrolyte leakage after this heat treatment was calculated based on the following formula (i), and the electrolyte leakage prevention property was evaluated according to the following criteria.
○: The weight change rate is less than 10%.
X: The weight change rate is 10% or more.

[Equation 1]
Weight change rate (%) = [(initial weight−weight after evaluation test) / weight of electrolytic solution] × 100 (i)

<Workability>
The workability when producing each of the dye-sensitized solar cells was evaluated according to the following criteria.
○… The squeegee method is unnecessary.
×… Applicable only if the squeegee method is used.

  From the above results, it can be seen that the dye-sensitized solar cells of the examples are excellent in solvent resistance, gas barrier properties, and adhesiveness because the electrolyte solution is very difficult to leak. Moreover, it turns out that it is excellent also in the evaluation of workability.

  On the other hand, in all the comparative examples, the electrolyte solution leaked, resulting in poor electrolyte solution leakage prevention properties. Moreover, since the comparative example 3 did not use the frame, it resulted in inferior workability | operativity to apply | coat to uniform thickness. And since the process of forming the gas barrier layer is increasing in the comparative example 4 in addition to the process of the comparative example 3, it became a result inferior to workability compared with the comparative example 2.

By the way, regarding Example 1, when SiO ₂ was vapor-deposited on the surface of the frame material used therefor, various performances similar to Example 1 described above were confirmed, and gas barrier properties of the dye-sensitized solar cell were confirmed. Was confirmed to be even higher.

  The sealing material for a dye-sensitized solar cell of the present invention is provided between the electrode substrates of the dye-sensitized solar cell, and is used as a sealing material for sealing an electrolyte in the dye-sensitized solar cell. In addition to being used, it can also be used as a sealing material (adhesive) to prevent gas leakage and liquid leakage from the joint interface between the solid gasket and the electrode substrate in conventional dye-sensitized solar cells. it can.

It is the top view (A) which shows an example of the dye-sensitized solar cell using the sealing material for dye-sensitized solar cells of this invention, and its A-A 'sectional drawing (B). In the sealing material for dye-sensitized solar cells of this invention, it is the top view (A) which shows a frame material, and its A-A 'sectional drawing (B). In the sealing material for dye-sensitized solar cells of this invention, it is the top view (A) which shows the state (frame body) which formed the adhesive coating film in the frame material, and its AA 'sectional drawing (B). . In the manufacture of a dye-sensitized solar cell, there are a plan view (A) showing a state in which the frame body of the present invention is disposed on an electrode substrate, and an A-A ′ sectional view (B) thereof. It is sectional drawing which shows an example of the conventional dye-sensitized solar cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 5 Electrolyte solution 7 Outer frame 10 Inner frame 8,11 Frame material which has gas-barrier property 9,12 Adhesive coating film 13,14 Electrode board

Claims (7)

In a dye-sensitized solar cell, a sealing material interposed between the two electrode substrates to form a space for enclosing the electrolyte solution between two opposing electrode substrates, the electrolyte solution and A frame member having a gas barrier property and a surface of the frame member in contact with the two electrode substrates; and an inner frame member that is in contact with the outer frame member. The adhesive coating film of the outer frame is made of a resin composition having the following (X) as an essential component, and the adhesive coating film of the inner frame is: A sealing material for a dye-sensitized solar cell, comprising a resin composition containing Y) as an essential component and having a higher solvent resistance than an adhesive coating film of an outer frame.
(X) Fluorine compound.
(Y) A fluorine compound different from the above (X).   The encapsulant for a dye-sensitized solar cell according to claim 1, wherein the adhesive coating film of the outer frame body and the inner frame body is made of a room temperature curable resin composition.   The encapsulant for a dye-sensitized solar cell according to claim 1 or 2, wherein the frame material having gas barrier properties is made of a resin composition containing ethylene-vinyl alcohol copolymer (EvOH) as a main component. The dye sensitization according to any one of claims 1 to 3, wherein the resin composition containing the fluorine compound (X) as an essential component is a resin composition mainly containing the following (a) to (c). Type solar cell encapsulant.
(A) A fluoropolyether compound having at least two hydroxyl groups in one molecule and having a perfluoropolyether structure in the main chain of the molecule.
(B) Isocyanate compound.
(C) Reaction catalyst. The said (a) component is what is shown to following General formula (1), The sealing material for dye-sensitized solar cells of Claim 4.

  The component (Y) is a fluoropolyether compound having at least two hydrolyzable groups in one molecule and having a perfluoropolyether structure in the main chain of the molecule. The sealing material for dye-sensitized solar cells as described in any one of Claims. The said (Y) component is what is shown to following General formula (2), The sealing material for dye-sensitized solar cells as described in any one of Claims 1-6.

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