JP6802802B2 - Sealant - Google Patents

Description

The present invention relates to a sealant particularly suitable for the manufacture of photoelectric conversion elements, which has excellent adhesiveness under low temperature curing conditions.

Solar cells, which are attracting attention as a clean energy source, have been used for general houses in recent years, but have not yet become sufficiently widespread. The reason is that it is hard to say that the power generation performance of the solar cell itself is sufficiently excellent, so the module has to be enlarged, and the productivity in module manufacturing is low, resulting in high cost. That can be mentioned.

Photoelectric conversion elements used in solar cells generally protect photoelectric conversion materials such as silicon, gallium-arsenide, and copper-indium-selenium with a transparent protective material at the top and a substrate protective material at the bottom, and the photoelectric conversion material and the protective material. And are fixed with a sealant and packaged. Therefore, as a sealant used in the manufacture of a photoelectric conversion element, good adhesion to upper and lower protective materials, excellent flexibility and durability, and the like are required as important performances.

For example, at present, an ethylene-vinyl acetate copolymer having a high vinyl acetate content is used as a sealant for a photoelectric conversion element in a solar cell module from the viewpoint of flexibility, transparency and the like. However, since the copolymer has insufficient heat resistance and adhesiveness, it is necessary to use an organic peroxide or the like for the purpose of further promoting the copolymerization reaction. In this case, a two-step step is required in which a sheet of an ethylene-vinyl acetate copolymer containing these organic peroxides is first prepared, and then the photoelectric conversion material is sealed using this sheet. Then, in the sheet manufacturing stage, it is necessary to mold at a low temperature so that the organic peroxide does not decompose, so that the extrusion molding speed cannot be increased. On the other hand, in the stage of sealing the photoelectric conversion material (curing adhesion), a step of temporarily adhering with a laminator over several minutes to a dozen minutes and a process of temporarily adhering the organic peroxide in the oven at a high temperature of several tens of minutes to 1 It is necessary to go through a two-step process consisting of a process of main bonding over time. Therefore, it takes time and effort to manufacture the photoelectric conversion element, and in addition, there is an inconvenience that the adhesiveness and moisture resistance reliability are not sufficient. Solar cell modules and solar cells using such a photoelectric conversion element become expensive and unsatisfactory in their performance.

Further, when the copolymer and an ionomer having a low melting point are used in combination as a sealing material for a photoelectric conversion element, the heat resistance is not sufficient and there is a risk of deformation due to a temperature rise during use as a solar cell. Further, when the photoelectric conversion element is manufactured by the heat-bonding method, these sealing materials may flow out more than necessary to cause burrs, which is not preferable. Further, as the size of the photoelectric conversion element has increased in recent years, the stress applied to the seal portion during the processing process has become much larger than before, and the seal wire length has also become longer. From these facts, a coating type sealant having excellent moisture resistance and reliability, making it possible to narrow the line width of the seal, making the distance between the conductive supports uniform, and having excellent adhesion and flexibility. Development is required.

On the other hand, a method of using a thermosetting epoxy resin as a sealing agent has been studied (Patent Document 1). In this case, the sealant is applied to the conductive support by a method such as dispenser or screen printing, leveling is performed with or without heating, and then the upper and lower conductive supports are bonded together using the alignment mark, and the sealant is used. Cell production is performed in the process of pressing. As the curing agent for the thermosetting epoxy resin used here, a phenol novolac resin is used. However, such a sealant for a photoelectric conversion element has an inconvenience that the adhesive performance is inferior in terms of long-term sealing performance under high temperature and high humidity, and the electrolytic solution leaks. Further, there is an inconvenience that the manufacturing load is large, such as a high temperature of 120 ° C. or higher is required when the sealant is cured. As a method for solving this inconvenience, Patent Document 2 discloses a resin composition using a hydrogenated bisphenol type epoxy resin. However, even in this case, the long-term sealing property under high temperature and high humidity cannot be imparted, and an event that the electrolytic solution leaks has been shown.

JP-A-2002-368236 JP-A-2007-087684

C. J. Barbe, F Arendse, P Compt and M. Graetzel J.M. Am. Seram. Soc. , 80, 12, 3157-71 (1997).

An object of the present invention is that the upper and lower conductive supports can be easily bonded at the time of manufacturing a photoelectric conversion element, and can be cured at a low temperature, and the obtained seal portion has adhesive strength, moisture resistance reliability, and heat resistance. An object of the present invention is to provide a sealant for a photoelectric conversion element having excellent properties. That is, an object of the present invention is to provide a sealant particularly suitable for manufacturing a photoelectric conversion element.

As a result of diligent research, the present inventors have found that a resin composition having a specific composition solves the above-mentioned problems, and have completed the present invention.
That is, each aspect of the present invention is as follows.
[1]. (A), characterized in that it contains an amine as the epoxy resin and (b) heat-curing agent, photoelectric conversion換素Ko sealant.
[2]. The above [1] contains (a) an amount of (b) a thermosetting agent in which the amount of active hydrogen in the thermosetting agent is 0.8 to 3.0 equivalents with respect to 1 equivalent of an epoxy group in the epoxy resin. ] photoelectric conversion換素Ko sealing agent according to claim.
[3]. (B) The sealant for a photoelectric conversion element according to the above item [1] or [2], wherein the thermosetting agent is an amine adduct.
[4]. (B) The above [1] to [3], wherein the thermosetting agent contains at least two kinds of amines including at least one kind of guanamines and / or imidazoles and at least one kind of other amines. The sealant for a photoelectric conversion element according to any one of the items.
[5]. The sealant for a photoelectric conversion element according to the above item [4], wherein the imidazoles contain 2-undecylimidazole.
[6]. (C) The sealant for a photoelectric conversion element according to any one of the above items [1] to [5], which contains a filler.
[7]. (C) The filler is one or more selected from the group consisting of hydrous magnesium silicate, calcium carbonate, aluminum oxide, crystalline silica and fused silica, and the average particle size thereof is 50 μm or less. The sealant for a photoelectric conversion element according to item [6].
[8]. (D) The sealant for a photoelectric conversion element according to any one of the above items [1] to [7], which contains a silane coupling agent.
[9]. (D) The sealant for a photoelectric conversion element according to the above item [8], wherein the silane coupling agent is glycidyl ethoxysilanes or glycidyl methoxysilanes.
[10]. A first conductive support having a semiconductor-containing layer, a second conductive support having counter electrodes provided at positions where the semiconductor-containing layer and a counter electrode face each other at predetermined intervals, first and second A photoelectric conversion element including a charge transfer layer sandwiched between the conductive supports of the above and a seal provided around the first and second conductive supports and surrounding the charge transfer layer. A photoelectric conversion element in which the seal is a seal formed from the sealant for a photoelectric conversion element according to any one of the above items [1] to [9].
[11]. A solar cell having the photoelectric conversion element according to the above item [10].

Since the sealant for a photoelectric conversion element of the present invention contains amines (preferably amine adduct) as a thermosetting agent, it has workability for coating on a substrate, adhesiveness, adhesive strength, and usable time at room temperature (pot). Life), excellent in low temperature curability. Therefore, the contamination of the charge transfer layer in the manufacturing process of the photoelectric conversion element is extremely low. The photoelectric conversion element of the present invention obtained by using such a sealing agent is excellent in adhesiveness and moisture resistance reliability with little deterioration in power generation performance due to contamination of the charge transfer layer. Further, when a photoelectric conversion element is manufactured using the sealant for a photoelectric conversion element of the present invention, it is possible to manufacture an element having high reliability at a low temperature in a short time without causing performance defects. Enables increased productivity.

It is sectional drawing of the main part explaining the structure of the dye-sensitized electric conversion element prepared by using the sealant of this invention.

The photoelectric conversion element sealant of the present invention (hereinafter, sometimes simply referred to as "sealant") is, (a) an epoxy resin and (b) photoelectric containing amines as hardener varying換素Ko curable It is a resin composition. This sealant preferably has a first conductive support having a semiconductor-containing layer, and a second conductive support having counter electrodes provided at positions where the semiconductor-containing layer and counter electrodes face each other at predetermined intervals. Includes a support, a charge transfer layer sandwiched between the first and second conductive supports, and a seal provided around the first and second conductive supports and surrounding the charge transfer layer. It is used as a raw material for the seal in a photoelectric conversion element.
Unless otherwise specified, the sealant of the present invention refers to a composition in a state before being subjected to a thermosetting process.

As the (a) epoxy resin used in the present invention, an epoxy resin having at least two or more epoxy groups in one molecule is usually used. Examples of such an epoxy resin include novolak type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, triphenylmethane type epoxy resin and the like. More specifically, bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, terpendiphenol, 4,4'-biphenol, 2,2'-biphenol, 3,3', 5,5'-tetramethyl-[ 1,1'-biphenyl] -4,4'-diol, hydroquinone, resorcin, naphthalenediol, tris- (4-hydroxyphenyl) methane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, phenol (Phenols, alkyl-substituted phenols, naphthols, alkyl-substituted naphthols, dihydroxybenzene, dihydroxynaphthalene, etc.) and formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, o-hydroxybenzaldehyde, p-hydroxyacetophenone, o-hydroxyacetophenone, dicyclo pentadiene, furfural, 4,4'-bis (chloro-methyl) -1,1'-biphenyl, 4,4'-bis (methoxymethyl) -1,1'-biphenyl, 1,4-bis (chloromethyl) Polycondensate with benzene, 1,4-bis (methoxymethyl) benzene, etc. and their modified products, halogenated bisphenols such as tetrabromobisphenol A, glycidyl etherified products derived from alcohols, alicyclic epoxy resin , Solid or liquid epoxy resins such as glycidylamine-based epoxy resin and glycidyl ester-based epoxy resin, but are not limited thereto. These may be used alone or in combination of two or more. These epoxy resins are useful for lowering the viscosity of the sealant for a photoelectric conversion element of the present invention, and may have an action of enabling laminating work at room temperature and facilitating gap formation. Among these epoxy resins, it is preferable to use a novolak type epoxy resin and / or a bisphenol A type epoxy resin and / or a bisphenol F type epoxy resin, and it is also preferable to use a novolak type epoxy resin and a bisphenol A type epoxy resin in combination. .. It is also preferable to use two types of epoxy resins having different epoxy equivalents in combination. In one embodiment, 30-300 g / eq . Epoxy resin and 200-600 g / eq . A mixture with the epoxy resin of the above may be used. Further, as one embodiment, 30 to 300 g / eq . Novolac type epoxy resin and / or bisphenol A type epoxy resin and / or bisphenol F type epoxy resin, and 200 to 600 g / eq . A mixture of novolak type epoxy resin and / or bisphenol A type epoxy resin and / or bisphenol F type epoxy resin may be used.

The sealant of the present invention preferably contains as little hydrolyzable chlorine as possible in the sealant in order to minimize contamination of the charge transfer layer by the sealant. Therefore, as for (a) epoxy resin, the amount of hydrolyzable chlorine contained therein is preferably 600 ppm or less, more preferably 500 ppm or less, even more preferably 400 ppm or less, and even more preferably 300 ppm or less. It is preferable that it is 200 ppm or less, more preferably 100 ppm or less, or substantially zero. The amount of hydrolyzable chlorine is quantified by, for example, dissolving about 0.5 g of epoxy resin in 20 ml of dioxane, refluxing it in 5 ml of 1N KOH / ethanol solution for 30 minutes, and then titrating it with 0.01N silver nitrate solution. can do.

The content of the (a) epoxy resin in the sealant of the present invention is usually 5 to 80% by mass, preferably 10 to 70% by mass, and more preferably 20 to 60% by mass.

The sealant of the present invention (b) contains amines as a thermosetting agent. The amines are not particularly limited, but polyfunctional amines having two or more amino groups in the molecule are preferably used. Preferred specific examples of polyfunctional amines having two or more amino groups in the molecule are synthesized from dimers of diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, linolenic acid and ethylenediamine. Polyamide resin, amine adduct and the like can be mentioned. One of the particularly preferred amines is amine adducts.
As the thermosetting agent in the present application, a curing agent capable of curing the seal at a temperature lower than 120 ° C. can be preferably used. More preferably, a curing agent capable of curing the seal at a temperature lower than 110 ° C. can be used. More preferably, a curing agent capable of curing the seal can be used at a temperature lower than 105 ° C., most preferably around 100 ° C. (or 100 ° C. or lower).

The above-mentioned amine adduct is an amine compound obtained by chemically reacting an epoxy resin with polyfunctional amines. Specific examples of Amin Adduct include product name, Hardener X-3661S, Hardener X-3670S (manufactured by ACR Co., Ltd.), Amicure PN-23, PN-31, PN-40, MY-24 (Ajinomoto Fine Techno). (Made by Asahi Kasei E-Materials Co., Ltd.), NovaCure HX-3742, HX-3721, HX-3722, HX-3088, HX-3741 (manufactured by Asahi Kasei E-Materials Co., Ltd.) and the like.
The "amine adduct" as a component of the sealant of the present invention referred to here is a reaction product of (a) epoxy resin and (b) amines obtained by subjecting the sealant to a thermosetting process. Does not contain amine adduct as one of. Although not intended to be bound by theory, this amine adduct needs to be in the form of adduct prior to thermosetting, as it is added primarily for the purpose of lowering the temperature of thermosetting.

It is preferable that these amine adducts have a fine particle size and are uniformly dispersed in the epoxy resin so as to act as a latent curing agent. The average particle size of the amine adduct obtained by chemically reacting polyfunctional amines or this with an epoxy resin is the cell gap of the photoelectric conversion element (distance between the first conductive support and the second conductive support). ), It is possible to successfully form a gap when the two substrates (conductive supports) of the photoelectric conversion element are bonded together. Therefore, the average particle size may be usually cell gap or less, preferably 15 μm or less, more preferably 12 μm or less, still more preferably 9 μm or less. The particle size of these amines can be measured by, for example, a laser diffraction / scattering type particle size distribution measuring device (dry type) (LMS-30, manufactured by Seishin Enterprise Co., Ltd.).

As the (b) thermosetting agent contained in the sealant of the present invention, at least one of guanamines and / or imidazoles and at least one of other amines (preferably the above-mentioned amine adduct) are used in combination. You may. The combination can guanamines, not particularly limited, for example, dicyandiamide, o- tolyl biguanide, acetoguanamine, benzoguanamine, full E sulfonyl acetamide guanamines and the like.

The imidazoles that can be used in combination are not particularly limited, and for example, 2-ethylimidazole, 2-methylimidazole, 2-phenylimidazole, 2-undecyl imidazole, 2-heptadecyl imidazole, 2-ethyl-4-methyl imidazole, 2-Phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2 -Undecylimidazole, 2,4-dicyano-6 (2'-methylimidazole (1')) ethyl-s-triazine, 2,4-dicyano-6 (2'-undecylimidazole (1')) ethyl- Examples thereof include s-triazine. Of these, 2-methylimidazole, 2-undecylimidazole, and 2-heptadecylimidazole are preferable. 2-Undecylimidazole is more preferable from the viewpoint of curability at low temperature, pot life, sealing properties after curing, and the like. (B) As the thermosetting agent, the combined use of amine adduct and guanamines or imidazoles is preferable, the combined use of amine adduct and imidazoles is more preferable, and the combined use of amine adduct and 2-undecylimidazole is most preferable.

Other heat-curing agents that can be used in combination include, for example, phenol-formaldehyde polycondensate, cresol-formaldehyde polycondensate, hydroxybenzaldehyde-phenol polycondensate, cresol-naphthol-formaldehyde polycondensate, resorcin-formaldehyde polycondensate. Phosphorus, furfural-phenol polycondensate, polyfunctional novolacs such as α-hydroxyphenyl-ω-hydropoly (biphenyldimethylene-hydroxyphenylene), bisphenol A, bisphenol F, bisphenol S, thiodiphenol, 4,4'- Biphenylphenol, dihydroxynaphthalene, fluorenbisphenol, terpendiphenol, 2,2'-biphenol, 3,3', 5,5'-tetramethyl- [1,1'-biphenyl] -4,4'-diol, hydroquinone , Resolcin, naphthalenediol, tris- (4-hydroxyphenyl) methane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, phenols (phenols, alkyl-substituted phenols, naphthols, alkyl-substituted naphthols, dihydroxybenzenes) Etc.) and formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, o-hydroxybenzaldehyde, p-hydroxyacetophenone, o-hydroxyacetophenone, dicyclopentadiene, furfural, 4,4'-bis (chloromethyl) -1,1' Polycondensate with -biphenyl, 4,4'-bis (methoxymethyl) -1,1'-biphenyl, 1,4'-bis (chloromethyl) benzene, 1,4'-bis (methoxymethyl) benzene, etc. And these modified products, halogenated bisphenols such as tetrabromobisphenol A, polyhydric phenolic curing agents such as condensates of terpenes and phenols, or phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, anhydrous. Acid anhydride-based curing agents such as maleic acid, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, benzophenonetetracarboxylic acid anhydride, and having 5 or less carbon atoms. Examples include aliphatic hydrazides. Any one of these thermosetting agents that can be used in combination may be used, or two or more types may be used in combination.
The amount of these thermosetting agents that can be used in combination is usually 0% by mass or more and 50% by mass or less, preferably 30% by mass or less, based on the total amount of the (b) thermosetting agent in the sealant of the present invention. In one embodiment, the sealant does not contain these thermosetting agents (other than amines) that can be used in combination. In another embodiment, the sealant thermosetting agent comprises only amines (particularly preferably amine adducts) or guanamines or imidazoles and other amines (particularly preferably amine adducts). You can.

The content of (b) the thermosetting agent used in the sealant for a photoelectric conversion element of the present invention is based on (a) one equivalent of an epoxy group in the epoxy resin used in the sealant for a photoelectric conversion element of the present invention. (B) The amount of active hydrogen in the thermosetting agent is usually 0.8 to 3.0 equivalents, preferably 0.8 to 2.5 equivalents, more preferably 0.8 to 2.0 equivalents, and even more preferably 0. The amount is 9 to 2.0 equivalents, most preferably 0.9 to 1.8 equivalents. The active hydrogen referred to here means a hydrogen atom bonded to a hetero atom of a thermosetting agent capable of reacting with an epoxy group contained in an epoxy resin.
In one embodiment, the sealant for a photoelectric conversion element of the present invention is, as a curing agent, either a polythiol compound having two or more thiol groups in the molecule and a polyhydrazide compound having two or more hydrazide groups in the molecule. It may not include both.

The sealant for a photoelectric conversion element of the present invention may contain (c) a filler, if necessary. Specific examples of the filler used (c) include fused silica, crystalline silica, silicon carbide, silicon nitride, boron nitride, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, and alumina (aluminum oxide). ), Magnesium oxide, zirconium oxide, aluminum hydroxide, magnesium hydroxide, hydrous magnesium silicate, calcium silicate, aluminum silicate, lithium aluminum silicate, zirconium silicate, barium titanate, glass fiber, carbon fiber, molybdenum disulfide, asbestos, etc. Can be mentioned. Of these, preferred examples include hydrous magnesium silicate, calcium carbonate, aluminum oxide, crystalline silica and fused silica. These may be surface-treated by chemical treatment or the like. The surface treatment can be performed with an organic compound such as a silane coupling agent. Any one of these fillers may be used, or two or more of these fillers may be mixed and used. The filler (c) that can contain the sealant of the present invention preferably has an average particle size of 50 μm or less, more preferably an average particle size of 40 μm or less, and even more preferably an average particle size of 30 μm or less. The average particle size of 20 μm or less is even more preferable, the average particle size of 10 μm or less is even more preferable, and the average particle size of 5 μm or less is most preferable. When the average particle size is 50 μm or less, an appropriate gap can be formed when the upper and lower substrates are bonded at the time of manufacturing the photoelectric conversion element. The average particle size of the filler here is, for example, the particle size in which the cumulative amount from the smaller particle is 50% by mass in the particle size distribution curve measured using a laser diffraction / scattering type particle size analyzer. Is.

(C) The content when the filler is used is usually 0 to 60% by mass or less, preferably 5 to 60% by mass, and more preferably 15 to 50% by mass in the sealant for a photoelectric conversion element of the present invention. .. When the content of the filler is 60% by mass or less, it is possible to form an appropriate cell gap for holding the charge transfer layer when the photoelectric conversion element is manufactured.

In the sealant for a photoelectric conversion element of the present invention, (d) a silane coupling agent can be used in order to improve the adhesive strength. (D) As the silane coupling agent, any silane coupling agent can be used as long as it improves the adhesive strength between the sealing agent and the conductive support. Specific examples of the silane coupling agent that can be used, 3-glycidoxypropyltrimethoxysilane, glycidyl silane such as 3-glycidoxypropyl methyldimethoxysilane Sila emissions, 2- (3,4-epoxycyclohexyl) ethyl trimethoxysilane, N- phenyl--γ- aminopropyltrimethoxysilane, N- (2- aminoethyl) aminopropyl methyl dimethoxy Sila down, 3-aminopropyltriethoxysilane, 3-mercaptopropyl triethoxysilane, vinyl Trimethoxysilane, N- (2- (vinylbenzylamino) ethyl) 3-aminopropyltriethoxysilane hydrochloride, 3-methacryloxypropyltriethoxysilane, 3-chloropropylmethyldiethoxysilane, 3-chloropropyltriethoxy Examples thereof include glycidylethoxysilanes such as silane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane. Among these, glycidyl ethoxysilanes or glycidyl methoxysilanes are preferable. Of these, a silane coupling agent having an amino group is preferable in order to obtain good adhesive strength. As preferable of the above silane coupling agent, N- (2- aminoethyl) aminopropyl methyl dimethoxy Sila down, 3-aminopropyltriethoxysilane, N-(2-(vinyl benzylamino) ethyl ) 3-Aminopropyltriethoxysilane hydrochloride and the like. One of these silane coupling agents may be used, or two or more of these silane coupling agents may be mixed and used. The content of the silane coupling agent used in the present invention is usually 0 to 2 % by mass , preferably 0.1 to 2 % by mass, and more preferably 0.2 to 1 % by mass in the sealant for a photoelectric conversion element of the present invention. It is 5% by mass. Further, in one embodiment, the silane coupling agent used in the present invention is (a) 100 parts by mass of the epoxy resin, for example, 0 to 20 parts by mass, and typically 0.1 to 10 parts by mass. Parts, preferably 0.5 to 10 parts by mass, more preferably 1 to 10 parts by mass, still more preferably more than 1 part by mass and up to 10 parts by mass, most preferably 1.5 to 10 parts by mass. It is 8 parts by mass.

The sealant for a photoelectric conversion element of the present invention may contain an organic solvent, an organic filler, a stress relaxation agent and the like, if necessary. In addition, additives such as pigments, leveling agents, defoaming agents, and viscosity modifiers can be further added to the sealing agent. The additives that can be blended are not particularly limited, and the amount of the additives to be added may be appropriately selected according to the purpose. These additives are preferably those having low contamination with the charge transfer layer.

The sealant for a photoelectric conversion element of the present invention comprises the above-mentioned (a) epoxy resin, (b) thermosetting agent containing amines, optionally (c) filler, (d) silane coupling agent and various additives. , In any order, preferably mixed with stirring so as to have each of the above-mentioned contents, and then uniformly mixed by a mixing device such as a three-roll, sand mill, or ball mill. Can be done. If necessary, filtration may be performed to remove contaminants after mixing is complete.

The sealant for a photoelectric conversion element of the present invention is suitable for a method for producing a photoelectric conversion element in which a charge transfer layer is injected from an injection port after two substrates (conductive supports) are bonded together. Sealing can be performed by heating and curing the weir of the sealant of the present invention sandwiched between two substrates. Examples of the method for applying the sealant of the present invention to the substrate include coating methods such as a bar coater method, a dip coating method, a spin coating method, a spray method, a screen printing method, a doctor blade method, and a dispensing method. , Can be appropriately selected or used in combination depending on the form. From the viewpoint of productivity, it is preferable to use the spray method, the screen printing method, and the dispense method. The sealant for a photoelectric conversion element of the present invention can be generally applied to any photoelectric conversion element capable of converting light energy into electrical energy. A solar cell is a closed circuit in which lead wires are arranged so that the current generated from the photoelectric conversion element can be taken out. The sealant for a photoelectric conversion element of the present invention is particularly suitable for manufacturing a dye-sensitized photoelectric conversion element and a solar cell having the photoelectric conversion element.

Hereinafter, the photoelectric conversion element and the solar cell manufactured by using the sealant for the photoelectric conversion element of the present invention will be described in detail. The following specific embodiments are merely examples, and the present invention is not limited thereto.
In general, a dye-sensitized photoelectric conversion element includes a first conductive support (oxide semiconductor electrode) having a dye-sensitized semiconductor-containing layer on its surface, and a second conductive support as a counter electrode. And the charge transfer layer is configured as a main component. The sealant for a photoelectric conversion element of the present invention is used for the purpose of adhering the first and second conductive supports and holding a charge transfer layer between the two supports. As the conductive support, for example, a conductive substance typified by FTO (fluorine-doped tin oxide), ATO (antimony-doped tin oxide), and ITO (indium-doped tin oxide) is used as glass, plastic, polymer film, quartz, or silicon. A thin film is used on the surface of the substrate. The thickness of the substrate is usually 0.01 to 10 mm, and the shape can take various forms from a film shape to a plate shape, but a light-transmitting substrate is used for at least one of the two substrates. .. The conductivity of the conductive support is usually 1000 [Omega] / cm ² or less, preferably 100 [Omega / cm ² or less.

As the oxide semiconductor used for preparing the semiconductor-containing layer, fine particles of metal carkenide are preferable. Specific examples Ti, Zn, Sn, Nb, W, In, Zr, Y, La, oxides of transition metals such as Ta, an oxide of Al, an oxide of _{Si, SiTiO 3, CaTiO 3,} BaTiO 3 Perovskite-type oxides and the like can be mentioned. Of these, TiO ₂ , ZnO, and SnO ₂ are particularly preferable. These may be used as a _mixture, SnO 2 -ZnO mixed system may be mentioned as preferred examples. In the case of a mixed system, it may be mixed in the state of fine particles, mixed in the state of slurry or paste described below, or each component may be used in layers. The concentration of the oxide semiconductor in the slurry or paste is usually 1 to 90% by mass, preferably 5 to 80% by mass. The primary particle size of the oxide semiconductor used is usually 1 to 200 nm, preferably 1 to 50 nm.

The semiconductor-containing layer can be prepared by directly forming a thin film made of an oxide semiconductor on a substrate by vapor deposition, applying or coating a slurry or paste on the substrate, and then applying pressure to prepare the substrate. There are a method of electrically precipitating, a method of applying or coating a slurry or a paste on a substrate, and then drying, curing or firing. Examples of the coating or coating method include a bar coater method, a dip coating method, a spin coating method, a spray method, a screen printing method, a doctor blade method, a dispensing method and the like. These methods can be appropriately selected or used in combination depending on the type and form of the substrate. From the viewpoint of the performance of the oxide semiconductor electrode, the method using a slurry or a paste is preferable. The slurry is prepared, for example, by dispersing fine particles of a secondary agglomerated oxide semiconductor in a dispersion medium so that the average primary particle size is usually 1 to 200 nm using a dispersant, or by a sol-gel method. It is obtained by hydrolyzing alcokiside or the like, which is a precursor of an oxide semiconductor. Further, fine particles of oxide semiconductors having different particle size distributions may be mixed and used.

The dispersion medium for dispersing the slurry is not particularly limited as long as it can disperse the fine particles of the oxide semiconductor. As the dispersion medium, water, alcohols such as ethanol and tarpineol, ketones such as acetone and acetylacetone, and organic solvents such as hydrocarbons such as hexane are used. These may be mixed and used. The use of water is preferable in that the change in viscosity of the slurry is reduced.

A dispersion stabilizer or the like may be added to the slurry for the purpose of obtaining stable primary fine particles. Specific examples of the dispersion stabilizer used include polyhydric alcohols such as polyethylene glycol, self-cocondensates such as monohydric alcohols such as phenol and octyl alcohol, and copolymers between them; hydroxypropylmethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, etc. Cellulous derivatives such as carboxymethyl cellulose; polyacrylamide; acrylamide, (meth) acrylate or salts thereof, (meth) acrylate ester (methyl (meth) acrylate, ethyl (meth) acrylate, etc.), etc. Cocondensate; Polyacrylic acid-based derivative that is a copolymer of acrylamide, (meth) acrylic acid or a salt thereof, (meth) acrylic acid ester, etc. and a hydrophobic monomer such as styrene, ethylene, propylene, etc. and is water-soluble; Melamine Salts of sulfonic acid formaldehyde condensate; salts of naphthalene sulfonic acid formaldehyde condensate; high molecular weight lignin sulfonates; acids such as hydrochloric acid, nitric acid, acetic acid and the like, but are not limited thereto. Further, these dispersion stabilizers may be used alone or in combination of two or more.

Of these, polyhydric alcohols such as polyethylene glycol, self-condensates such as phenol and octyl alcohol, or cocondensates between them, poly (meth) acrylic acid, sodium poly (meth) acrylate, potassium poly (meth) acrylate. , Poly (meth) acrylate lithium, carboxymethyl cellulose, hydrochloric acid, nitrate, acetic acid and the like are preferable.

After the slurry coated on the conductive support is dried, the firing treatment can be performed at a temperature equal to or lower than the melting point (or softening point) of the substrate used for the conductive support. The firing temperature is usually 100 to 900 ° C, preferably 100 to 600 ° C. The firing time is not particularly limited, but is generally within 4 hours. The film thickness of the semiconductor-containing layer provided on the conductive support is usually 1 to 50 μm.

The semiconductor-containing layer may be subjected to a secondary treatment for the purpose of improving the surface smoothness (see Non-Patent Document 1). For example, a conductive support in which a thin film of the semiconductor-containing layer prepared by the above method is provided in a solution of the same metal alcoxide or chloride, nitrate, sulfide, etc. used for preparing the semiconductor-containing layer. The smoothness of the semiconductor-containing layer can be enhanced by directly immersing the body and drying it, or by optionally firing (re-baking) it in the same manner as described above. Here, examples of the metal alcoholide include titanium ethoxide, titanium isopropoxide, titanium t-butoxide, n-dibutyl-diacetyltin, and the like, and an alcohol solution thereof is used. In the case of chloride, for example, titanium tetrachloride, tin tetrachloride, zinc chloride and the like can be mentioned, and an aqueous solution thereof is used. The specific surface area of the semiconductor-containing layer made of the oxide semiconductor fine particles thus obtained is usually 1 to 1000 m ² / g, preferably 10 to 500 m ² / g.

Next, a step of supporting the sensitizing dye on the semiconductor-containing layer will be described. The sensitizing dye is not particularly limited as long as it has an action of sensitizing light absorption together with the semiconductor fine particles constituting the semiconductor-containing layer. As the sensitizing dye, a metal complex dye containing a metal element such as ruthenium or an organic dye containing no metal may be used alone, or several types may be mixed and used at an arbitrary ratio. When used in combination, any of a plurality of types of metal complex dyes, a plurality of types of organic dyes, and a combination of the metal complex dye and the organic dye may be used. By mixing a plurality of types of dyes having different absorption wavelength regions, a wide range of absorption wavelengths can be used, and a solar cell having high conversion efficiency can be obtained.

The metal complex dye that can be supported is not particularly limited, but phthalocyanine, porphyrin, and the like are preferable, and a ruthenium complex is more preferable. The organic pigments that can be carried are also not particularly limited. For example, methine pigments such as metal-free phthalocyanines, porphyrins and cyanines, merocyanines, oxonors, triphenylmethanes, acrylic acid pigments, pyrazolone methine pigments, and xanthene pigments. , Azo-based, anthraquinone-based, perylene-based pigments and the like. International Publication Patent WO2002-001667, International Patent WO2002-011213, International Patent WO2002-071530, JP2002-334729, JP2003-007358, JP2003-017146 , JP-A-2003-059547, JP-A-2003-086557, JP-A-2003-115333, JP-A-2003-132965, JP-A-2003-142172, JP-A-2003-151649, Kai 2003-157915, JP2003-282165, JP2004-014175, JP2004-022222, JP2004-022387, JP2004-227825, JP2005 -005026, Japanese Patent Application Laid-Open No. 2005-0119130, Japanese Patent Application Laid-Open No. 2005-135656, Japanese Patent Application Laid-Open No. 2006-079898, Japanese Patent Application Laid-Open No. 2006-134649, International Patent Publication No. WO2006-082061, etc. It is preferable to have. It is more preferable to use merocyanine, the above-mentioned methine-based pigments such as acrylic acid, and the like. The ratio of each dye when a plurality of kinds of dyes are mixed and used is not particularly limited, but it is generally preferable to use at least about 10 mol% or more of each dye. When the dye is supported on the semiconductor-containing layer by using a solution in which two or more kinds of dyes are dissolved or a dispersed dispersion, the total concentration of the dyes in the solution may be the same as in the case where only one kind is supported. As the solvent when a plurality of types of dyes are mixed and used, the above-mentioned solvent can be used for the oxide semiconductor, and the solvent for each dye used may be the same or different.

Examples of the method for supporting the sensitizing dye include a method of immersing the conductive support provided with the semiconductor-containing layer in a solution in which the dye is dissolved in a solvent or a dispersion in which the dye is dispersed in the solvent. The concentration of the dye in the solution or dispersion may be appropriately determined depending on the type and solubility of the dye. The immersion temperature is generally from room temperature to the boiling point of the solvent, and the immersion time may be about 1 hour to 72 hours. Specific examples of the solvent that can be used to dissolve the sensitizing dye include methanol, ethanol, acetone, acetonitrile, dimethylsulfoxide, dimethylformamide, t-butanol, tetrahydrofuran and the like. These may be used alone, or a plurality of them may be mixed and used at an arbitrary ratio. The concentration of the sensitizing dye in the solution is usually 1 × 10 ^-6 M to ¹ M, preferably 1 × 10 ^-5 M to ¹ × 10 ^-1 M. In this way, a conductive support having a dye-sensitized semiconductor-containing layer used as an oxide semiconductor electrode can be obtained.

When the dye is supported on the semiconductor-containing layer, it is effective to support the dye in the coexistence of the clathrate compound in order to prevent the association of the dye particles. Here, examples of the clathrate compound include steroid compounds such as cholic acid, crown ether, cyclodextrin, calixarene, polyethylene oxide and the like. Preferred are cholic acids such as cholic acid, deoxycholic acid, chenodeoxycholic acid, cholic acid methyl ester, sodium cholic acid and ursodeoxycholic acid, polyethylene oxide and the like. As a form of use of these clathrate compounds, the clathrate compound may be added to the dye solution, or the clathrate compound may be previously dissolved in a solvent and then the dye may be dissolved or dispersed. Two or more kinds of these clathrate compounds can be used in combination, and the ratio thereof can be arbitrarily selected.
Further, after supporting the dye, the semiconductor-containing layer may be treated with an amine compound such as 4-t-butylpyridine. As a treatment method, for example, a method of immersing a conductive support provided with a semiconductor-containing layer carrying a dye in an ethanol solution of an amine compound is adopted.

On the counter electrode, conductive fine particles such as platinum, carbon, rhodium, and ruthenium that act catalytically on the reduction reaction of the redox electrolyte are deposited on the surface of a conductive support such as FTO conductive glass, or these A precursor coated with conductive fine particles and fired is used.

Next, the conductive support (oxide semiconductor electrode) and the counter electrode having the semiconductor-containing layer sensitized with the dye obtained as described above are subjected to the sealing agent for the photoelectric conversion element of the present invention. The method of pasting together will be described.
First, the sealant of the present invention to which a spacer (gap control material) is added is applied by a dispenser, a screen printing machine, or the like, leaving an injection port of a charge transfer layer around the conductive surface of one of the conductive supports. After the coating is applied in a weir shape, the other conductive support can be overlapped and heated so that the conductive surfaces of the first and second conductive supports face each other, and the sealant can be cured. Here, as the spacer, for example, glass fiber, silica beads, polymer beads and the like, and metal-coated fine particles such as gold pearl and silver pearl are used. The average diameter varies depending on the purpose, but is usually 1 to 100 μm, preferably 10 to 40 μm. The amount used is usually 0.1 to 10 parts by mass, preferably 0.5 to 5 parts by mass, and more preferably 1 to 2.5 parts by mass with respect to 100 parts by mass of the sealant of the present invention. The conditions for heat curing of the sealant are usually 80 to 120 ° C. for 1 to 3 hours. As a method of heat curing, a method of sandwiching the sandwich with a heat press machine having two hot plates, a method of fixing with a jig and then performing in an oven, and the like can be adopted. The gap between the first and second conductive supports is usually 1 to 100 μm, preferably 4 to 50 μm.

The dye-sensitized electric conversion element of the present invention is completed by injecting a charge transfer layer into the gap between a pair of conductive supports bonded as described above. As the charge transfer layer, a solution in which a redox electrolyte pair, a hole transport material, or the like is dissolved in a solvent or a room temperature molten salt (ionic liquid) is used. As the redox electrolyte used, a halogen compound having a halogen ion as a counter ion and a halogen redox electrolyte composed of halogen molecules, a metal such as ferrocyanate-ferricanate, ferrocene-ferricinium ion, and cobalt complex. Examples thereof include metal redox electrolytes such as complexes, organic redox electrolytes such as alkylthiol-alkyldisulfides, viologen dyes, and hydroquinone-quinone. Halogen redox electrolytes are preferred. Examples of the halogen molecule in the halogen redox electrolyte include iodine molecule and bromine molecule, and iodine molecule is preferable. Examples of the halogen compound include metal halide salts such as LiI, NaI, KI, CsI, CaI ₂ , and CuI, or tetraalkylammonium iodide, imidazolium iodide, and 1-methyl-3-alkylimidazolium iodide. , Organic quaternary ammonium salt of halogen such as pyridinium iodide and the like. A salt compound having an iodine ion as a counter ion is preferable. Specific examples thereof include lithium iodide, sodium iodide, trimethylammonium iodide salt and the like. These may be used alone or in combination of two or more.

When the charge transfer layer is composed of a solution containing a redox electrolyte, an electrochemically inert solvent is used as the solvent. Specific examples of the solvent used include acetonitrile, valeronitrile, propylene carbonate, ethylene carbonate, 3-methoxypropionitrile, 3-butoxypropionitrile, methoxyacetonitrile, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol and dimethoxy. Ethan, diethyl carbonate, diethyl ether, dimethyl carbonate, 1,2-dimethoxyethane, dimethylformamide, dimethylsulfoxide, 1,3-dioxolane, methylformate, 2-methylnitrile, 3-methyloxazolidin-2-one, Examples thereof include γ-butyrolactone, sulfolane, tetrahydrofuran, water and the like. Among these, acetonitrile, propylene carbonate, ethylene carbonate, 3-methoxypropionitrile, methoxyacetonitrile, ethylene glycol, 3-methyloxazolidine-2-one, γ-butyrolactone and the like are preferable. These may be used alone or in combination of two or more. The concentration of the redox electrolyte in the solution is usually 0.01 to 99% by mass, preferably 0.1 to 90% by mass.

When the charge transfer layer is composed of a composition containing a redox electrolyte, a room temperature melt (ionic liquid) is used as a solvent. Specific examples of the room temperature melt used include 1-methyl-3-alkylimidazolium iodide, vinyl imidazolium tetrafluoride, 1-ethylimidazole sulfonate, alkylimidazolium trifluoromethylsulfonylimide, and 1-methyl. Examples thereof include pyrrolidinium iodide. Further, for the purpose of improving the durability of the photoelectric conversion element, for example, a low molecular weight gelling agent is dissolved in the charge transfer layer to thicken it, or a charge transfer layer containing a reactive component is reacted after injection. It is possible to obtain a gel electrolyte by gelling the gel or by impregnating a pre-polymerized gel with a charge transfer layer.

On the other hand, in the case of a completely solid type charge transfer layer, a hole transport material or a P-type semiconductor can be used instead of the redox electrolyte. Examples of the hole transport material used include amine derivatives and conductive polymers such as polyacetylene, polyaniline, and polythiophene. Further, examples of the P-type semiconductor include CuI and CuSCN.

A photoelectric conversion element can be obtained by injecting a charge transfer layer into the gap between the pair of conductive supports and then sealing the injection port of the charge transfer layer. As a sealing material (sealing agent) for sealing the injection port of the charge transfer layer, isobutylene resin, epoxy resin, UV curable acrylic resin and the like can be used.

On the other hand, the following method can also be adopted as another method for manufacturing the photoelectric conversion element. That is, a sealant weir is provided around the conductive surface of either of the conductive supports without providing a charge transfer layer injection port, and then a charge transfer layer similar to the above is provided inside the sealant weir. The other conductive support is placed and bonded so that the conductive surfaces of the first and second conductive supports face each other under reduced pressure, and at the same time, a gap is formed and then the sealant is cured. A photoelectric conversion element can be obtained.

FIG. 1 is a schematic cross-sectional view of a main part for explaining the structure of a dye-sensitized electric conversion element prepared by using the sealant of the present invention. In the figure, 1 is a conductive support having conductivity on the inside, 2 is a semiconductor-containing layer sensitized by a dye (1 and 2 are collectively referred to as an oxide semiconductor electrode), and 3 is a conductive support. A counter electrode in which platinum or the like is arranged on a conductive surface inside the body, 4 is a charge transfer layer arranged in a gap between a pair of conductive supports, and 5 is a sealant of the present invention. Reference numeral 6 is a glass substrate. The solar cell of the present invention can be obtained by arranging lead wires on the positive electrode and the negative electrode of the photoelectric conversion element thus obtained and inserting a resistance component between them.

Sealant of the present invention, a plurality of dye-sensitized solar cell planarly arranged, can be electrically applied to produce the dye-sensitized solar cell module having a large area which are connected in series. Several types of modular structures of dye-sensitized solar cells with a large area are known. The sealant of the present invention can be used in any type of modular structure. For example, it can also be used for a dye-sensitized solar cell module having a series connection structure described in International Patent Publication No. WO2009 / 057704.

The sealant for a photoelectric conversion element of the present invention is excellent in coating workability on a substrate, adhesion, adhesive strength, usable time at room temperature (pot life), and low temperature curability in the manufacturing process of the photoelectric conversion element. Very low pollution to the charge transfer layer. Therefore, the photoelectric conversion element of the present invention obtained by using the sealant has no malfunction due to contamination of the charge transfer layer, and is excellent in adhesiveness and moisture resistance reliability. The solar cell prepared by using the photoelectric conversion element can be efficiently manufactured and has excellent durability.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[Example 1]
(A) As an epoxy resin, RE-310S (trade name, bisphenol A type epoxy resin, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 185 g / eq., Hydrolyzed chlorine amount 400 ppm or less) EP-1001 (trade name) in 90 parts by mass , Bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 475 g / eq.) 10 parts by mass was added and dissolved by heating. After cooling this epoxy resin to room temperature, 90 parts by mass of SSP-07DM (trade name, surface-treated silica, maximum particle size of 0.7 μm) as a filler, and KBM-403 (d) a silane coupling agent (KBM-403). Product name, epoxy silane coupling agent (γ-glycidoxypropyltrimethoxysilane), manufactured by Shin-Etsu Silicone Co., Ltd.) 1 part by mass was added and mixed and dispersed by 3 rolls, and (b) PN- as a thermosetting agent. 31 (trade name, epoxy resin amine adduct, manufactured by Ajinomoto Fine Techno Co., Ltd., average particle size 8.8 μm) 20 parts by mass is added and further mixed and dispersed by three rolls to seal the photoelectric conversion element of the present invention. (1) was obtained. The viscosity of this sealant (1) at 25 ° C. was measured with an E-type viscometer and found to be 73 Pa · s.

[Comparative Example 1]
(A) 70 parts by mass of RE-310S as an epoxy resin, EPPN-501H (trade name, trisphenol methane novolac type epoxy resin, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 165 g / eq., Hydrolyzed chlorine amount 550 ppm or less) 20 parts by mass and YD-017 (trade name, bisphenol A type solid epoxy resin, manufactured by Toto Kasei Kogyo Co., Ltd., epoxy equivalent 1900 g / eq.) 10 parts by mass, (b) PN-152 as a heat curing agent (trade name, Phenol novolac resin, manufactured by Nippon Kayaku Co., Ltd., active hydrogen equivalent 100 g / eq.) 7.5 parts by mass, (d) 1 part by mass of KBM-403 as a silane coupling agent, 30 mass of ethylene glycol dibutyl ether as a solvent. It was melted by heating in the part. After cooling this solution to room temperature, (b) finely pulverized with a jet mill of isophthalic acid dihydrazide as a heat curing agent (melting point 224 ° C., active hydrogen equivalent 48.5 g / eq., Average particle size 1.7 μm). , Maximum particle size 7 μm) 19 parts by mass, (c) 90 parts by mass of alumina having an average particle size of 0.5 μm or less and 3.5 parts by mass of fumed silica as a filler, and mixed by three rolls. 5 parts by mass of 2,4-diamino-6- [2'-methylimidazolyl- (1')] -ethyl-s-triazine isocyanuric acid adduct, which is dispersed and has an average particle size of 3 μm or less as a curing accelerator. Was added to obtain a sealant (2) for a photoelectric conversion element. The viscosity of this sealant (2) at 25 ° C. was measured with an E-type viscometer and found to be 47 Pa · s.

[Example 2]
90 parts by mass of (a) RE-310S in Example 1 was changed to 80 parts by mass, and a new polyfunctional epoxy resin EPPN-501 (trade name, trisphenol methane novolac type epoxy resin, manufactured by Nippon Kayaku Co., Ltd.) (Epoxy equivalent 165 g / eq., Hydrolyzed chlorine amount 550 ppm or less) 10 parts by mass was added, (d) 1 part by mass of KBM-403 was changed to 3 parts by mass as a silane coupling agent, and (b) a thermosetting agent. The sealant (3) for a photoelectric conversion element of the present invention was obtained in the same manner as in Example 1 except that 3 parts by mass of C11Z (trade name, 2-undecylimidazole, manufactured by Shikoku Kasei Co., Ltd.) was added. The viscosity of this sealant (3) at 25 ° C. was measured with an E-type viscometer and found to be 278 Pa · s.

[Example 3]
90 parts by mass of (a) RE-310S in Example 1 was changed to 80 parts by mass, and a new polyfunctional epoxy resin EPPN-501 (trade name, trisphenol methane novolac type epoxy resin, manufactured by Nippon Kayaku Co., Ltd.) The sealant (4) for a photoelectric conversion element of the present invention was obtained in the same manner as in Example 1 except that 10 parts by mass (epoxy equivalent: 165 g / eq., Hydrolyzed chlorine amount: 550 ppm or less) was added. The viscosity of this sealant (4) at 25 ° C. was measured with an E-type viscometer and found to be 443 Pa · s.

[Example 4]
The sealant (5) for a photoelectric conversion element of the present invention was obtained in the same manner as in Example 1 except that 1 part by mass of KBM-403 was changed to 3 parts by mass as the (d) silane coupling agent in Example 1. It was. The viscosity of this sealant (5) at 25 ° C. was measured with an E-type viscometer and found to be 31 Pa · s.

[Example 5]
The photoelectric conversion element of the present invention is the same as in Example 1 except that 3 parts by mass of C11Z (trade name, 2-undecylimidazole, manufactured by Shikoku Kasei Co., Ltd.) is added as the (b) thermosetting agent in Example 1. Sealing agent (6) for use was obtained. The viscosity of this sealant (6) at 25 ° C. was measured with an E-type viscometer and found to be 80 Pa · s.

[Evaluation test 1]
The shear adhesive strength was measured as a performance evaluation of each of the sealants prepared in Examples 1, 3, 4, 5 and Comparative Example 1. Moreover, as a performance evaluation of each sealant produced in Example 2 and Comparative Example 1, the degree of swelling against a solvent was measured.

The shear bond strength was measured by the following method.
1 part by mass of glass fiber having a diameter of 50 μm was added as a spacer to 100 parts by mass of each sealant, and the mixture was mixed and stirred. This sealant is applied on a 50 mm × 50 mm conductive support (FTO glass substrate) with a dispenser, the solvent is volatilized by heating with a hot plate, and then 2 mm × 2 mm is applied on the sealant on the conductive support. The glass pieces were bonded together and cured under the condition of 100 ° C. for 1 hour, and the shear adhesive strength of the obtained test piece was measured.

The degree of swelling against solvent (degree of swelling) was measured by the following method.
Each sealant was applied onto a heat-resistant film using an applicator (thickness 200 μm) and cured under the condition of 100 ° C. for 1 hour. Four punching test pieces were prepared by applying a 3 cm × 3 cm punch blade to the obtained cured film. After measuring the mass (mass before immersion) of each test piece, the test piece was placed in a pressure-resistant container together with 3-methoxypropionitrile (3MPN), and the pressure-resistant container was heated at 85 ° C. for 2 hours. After the heating was completed, the pressure-resistant container was cooled to room temperature, 3MPN adhering to the taken-out test piece was wiped off, and the mass of the test piece (mass after immersion) was measured. The mass increase rate before and after immersion in the solvent was obtained from the calculation of {(mass after immersion / mass before immersion) -1} × 100, and the average value of the mass increase rates of the four sheets was taken as the swelling degree (%).

As the results of Tables 1 and 2 show, the sealants (1), (4), (5), and (6) of the present invention showed higher adhesive strength than the sealant (2). On the other hand, the sealant (3) of the present invention showed a lower degree of solvent swelling as compared with the sealant (2). These results show that the sealant of the present application is useful for manufacturing a dye-sensitized solar cell element at a low temperature (100 ° C.), and since the element can be manufactured at a low temperature, it is effective for manufacturing an energy-saving and highly reliable device. It suggests that there is.

The sealant for a photoelectric conversion element of the present invention is excellent in coating workability on a substrate, adhesion, adhesive strength, usable time at room temperature (pot life), and low temperature curability in the manufacturing process of the photoelectric conversion element. Very low pollution to the charge transfer layer. The photoelectric conversion element of the present invention obtained by using such a sealing agent has no malfunction due to contamination of the charge transfer layer, and has excellent adhesiveness and moisture resistance and reliability. Further, when the photoelectric conversion element is manufactured by using the sealant for the photoelectric conversion element of the present invention, performance failure does not occur and productivity can be improved.

1. 1. Conductive support 2. Semiconductor-containing layer sensitized by dye 3. Counter electrode 4. Charge transfer layer 5. Sealant 6. Glass substrate

Claims (7)

It contains (a) an epoxy resin and (b) only amine adduct as a thermosetting agent , or only a mixture of amine adduct and at least one mixture of guanamines and / or imidazoles, and (c) as a filler. A sealant for a photoelectric conversion element, which contains at least one selected from the group consisting of hydrous magnesium silicate, calcium carbonate, aluminum oxide, crystalline silica and molten silica, and surface-treated products thereof. Further, (a) the amount of active hydrogen in the thermosetting agent is 0.8 to 3.0 equivalents with respect to 1 equivalent of the epoxy group in the epoxy resin, and (b) the thermosetting agent is contained. A sealant for photoelectric conversion elements, which is characterized by this. The sealant for a photoelectric conversion element according to claim 1 , wherein the imidazoles contain 2-undecylimidazole. (C) The sealant for a photoelectric conversion element according to claim 1, wherein the average particle size of the filler is 50 μm or less. (D) The sealant for a photoelectric conversion element according to any one of claims 1 to 3 , which contains a silane coupling agent. (D) The sealant for a photoelectric conversion element according to claim 4 , wherein the silane coupling agent is glycidyl ethoxysilanes or glycidyl methoxysilanes. A first conductive support having a semiconductor-containing layer, a second conductive support having counter electrodes provided at positions where the semiconductor-containing layer and a counter electrode face each other at predetermined intervals, first and second A photoelectric conversion element including a charge transfer layer sandwiched between the conductive supports of the above, and a seal provided around the first and second conductive supports and surrounding the charge transfer layer. A photoelectric conversion element, wherein the seal is a seal formed from the sealant for a photoelectric conversion element according to any one of claims 1 to 5 . A solar cell comprising the photoelectric conversion element according to claim 6 .