JP2010177031A - Dye-sensitized solar cell and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dye-sensitized solar cell which prevents elution of a seal material constituent caused by an electrolytic liquid and does not produce swelling and deterioration on sealing for a long period and has a high sealing nature and is excellent on reliability and durability. <P>SOLUTION: In the dye-sensitized solar cell wherein a pair of electrode substrates 1, 1' are sealed by facing each other and the electrolytic liquid 5 is poured into the sealed air gap, a through-hole 12a for pouring the electrolytic liquid is formed on at least a part of the electrode substrates 1, 1', the through-hole 12a is sealed by an elastic curing body 12, and the electrolytic liquid 5 is poured into the through-hole while a needle for pouring the electrolytic liquid is penetrated into the elastic curing body 12. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a dye-sensitized solar cell in which a pair of electrode substrates are oppositely bonded and sealed, and an electrolyte solution is enclosed, and the dye-sensitized solar cell having high electrolyte solution sealing property and excellent durability, and It relates to the manufacturing method.

A dye-sensitized solar cell in which a redox electrolyte solution is sealed between a transparent conductive substrate with a semiconductor film such as TiO ₂ on which a dye is supported and a counter electrode substrate, has high conversion efficiency of sunlight and is inexpensive. Therefore, it is considered promising as a next-generation solar cell.

  However, when a redox electrolyte solution such as iodine or lithium iodide is sealed in a glass substrate or a plastic film substrate, the above-mentioned electrolyte can be obtained by using a conventionally used ethylene-methacrylic acid copolymer ionomer resin as a sealing material. This type of dye-sensitized solar cell has a problem of poor durability because liquid leakage and moisture absorption from the outside cannot be prevented.

  For this reason, it has been proposed to use a liquid epoxy resin or silicone resin as a sealing material instead of the ethylene-methacrylic acid copolymerized ionomer resin to seal (seal) the electrolyte solution (Patent Literature). 1). Further, as a dye-sensitized solar cell sealing material using an elastomer having relatively excellent electrolyte solution resistance, it contains a silane coupling agent and contains at least one alkenyl group capable of hydrosilylation reaction in the molecule. A sealing material obtained by polymerizing a polyisoprene polymer and an organohydrogenpolysiloxane with a hydrosilylation catalyst has been proposed (see Patent Document 2). On the other hand, the present inventors, as a photo-curing (ultraviolet-curing) type sealing material that does not cause expansion or deterioration in sealing over a long period of time and has high sealing performance, has at least one (meta) on at least one of both molecular ends. ) A photopolymerizable composition having a hydrogenated elastomer derivative having an acryloyl group as an essential component has been developed, and a dye-sensitized solar cell using this as a sealing material has been proposed (see Patent Document 3).

JP 2000-30767 A JP 2004-95248 A JP 2008-140759 A

  The cured product after heat-curing or photo-curing the sealing material has excellent electrolyte solution resistance, but there is a concern that the components of the sealing material may be eluted into the electrolyte solution. That is, in the conventional dye-sensitized solar cell, as shown in FIG. 2, the electrolyte solution 5 is injected from the injection port 10 into the gap of the seal (main seal) 7, and then the sealing material 8 is cured and poured. The inlet 10 is configured to be sealed (end seal). Therefore, the sealing material 8 comes into contact with the electrolyte solution 5 in an uncured state, and the components of the sealing material 8 may be eluted into the electrolyte solution 5 depending on the type of solvent used for the electrolyte solution 5. The eluted sealing material component may reduce the ionic conductivity of the electrolyte solution 5 and reduce the power generation efficiency, or may cause problems such as leakage of the electrolyte solution 5 itself due to insufficient sealing. . In FIG. 2, 1 and 11 are electrode substrates, 2 and 2 'are transparent conductive electrode films, 3 is a porous semiconductor film, 4 is a sensitizing dye, 5 is an electrolyte solution, 6 is a conductive film, and 9 is a cover material. It is.

  The present invention has been made in view of such circumstances, prevents elution of a sealing material component by an electrolyte solution, does not cause swelling or deterioration in long-term sealing, has extremely high sealing performance, and is reliable and durable. An object of the present invention is to provide an excellent dye-sensitized solar cell and a method for producing the same.

  In order to achieve the above object, the present invention provides a dye-sensitized solar cell in which a pair of electrode substrates are bonded and sealed facing each other, and an electrolyte solution is injected into the sealed gap. A through-hole for injecting an electrolyte solution is formed in at least a part of the substrate, and the through-hole is sealed with an elastic cured body, and the electrolyte solution injection needle is penetrated through the elastic cured body with the electrolyte solution injecting needle penetrated. The dye-sensitized solar cell that has been injected is a first gist. The present invention also relates to a method for producing the dye-sensitized solar cell, wherein the through hole formed in the electrode substrate is sealed with an elastic cured body, and then an electrolyte solution injection needle is attached to the elastic cured body. The manufacturing method of the dye-sensitized solar cell which penetrates and injects the electrolyte solution is a second gist.

  The inventors of the present invention provide a dye-sensitized solar cell that prevents elution of a sealing material component by an electrolyte solution, does not swell or deteriorate during long-term sealing, has extremely high sealing performance, and is excellent in reliability and durability. In order to obtain it, earnest research was repeated. As a result, the electrolyte solution injection through hole formed in at least a part of the electrode substrate is sealed with an elastic cured body, and the electrolyte solution injection is performed with the electrolyte solution injection needle penetrating the elastic cured body. As a result, it was found that the intended purpose can be achieved by the dye-sensitized solar cell in which the above is achieved, and the present invention has been achieved. That is, the dye-sensitized solar cell of the present invention is obtained by injecting the electrolyte solution into an elastic cured body (such as an elastomer cured body of a sealing material) while penetrating the electrolyte solution injection needle. Is sealed (sealed). Therefore, unlike the conventional case, the sealing material (end sealing material) remains uncured and does not come into contact with the electrolyte solution, and the solvent of the electrolyte solution does not cause the sealing material component to elute into the electrolyte solution. Therefore, the eluted sealing material component does not cause problems such as a decrease in ionic conductivity of the electrolyte solution, a decrease in power generation efficiency, and leakage of the electrolyte solution itself.

  As described above, in the dye-sensitized solar cell of the present invention, the through hole for electrolyte solution injection formed in at least a part of the electrode substrate is sealed by the elastic cured body, and the electrolyte solution injection for the elastic cured body is performed. The electrolyte solution is injected with the needle penetrated. When the electrolyte solution injection needle is pulled out, the hole of the needle is automatically closed by the elastic force of the elastic hardened body, and the electrolyte solution is sealed ( Sealed). Therefore, the leakage of the electrolyte solution can be prevented without using a sealing material (end sealing material) as in the prior art. Further, even when a sealing material (end sealing material) is used to protect the elastic cured body, the sealing material and the electrolyte solution do not come into direct contact, and the sealing material component is not likely to elute into the electrolyte solution. As described above, the dye-sensitized solar cell of the present invention can prevent elution of the sealing material component by the electrolyte solution, does not cause swelling or deterioration during long-term sealing, has extremely high sealing performance, reliability, and Excellent durability.

  The elastic cured body is made of an elastomer cured body of at least one sealing material selected from the group consisting of a silicone sealing material, a modified silicone sealing material, a fluorine-based polymer sealing material, an acrylic urethane sealing material, and a polyisobutylene sealing material. In some cases, the sealing performance, reliability and durability are further improved.

It is sectional drawing which shows an example of the dye-sensitized solar cell of this invention. It is sectional drawing which shows an example of the conventional dye-sensitized solar cell.

  Next, an embodiment for carrying out the present invention will be described.

  In the dye-sensitized solar cell of the present invention, for example, as shown in FIG. 1, electrode substrates 1 and 1 ′ are arranged at a predetermined interval with the conductive electrode surfaces of the substrates facing inside, The gap between the electrode substrates 1 and 1 ′ is sealed by disposing a sealing material 7 (main seal) on the peripheral edge of the inner surface of the substrates, and the electrolyte solution 5 is placed in the sealed gap. It is enclosed. A porous semiconductor film 3 is formed on the electrode substrate 1 via a transparent conductive electrode film 2, and a sensitizing dye 4 is adsorbed on the porous semiconductor film 3. A conductive film 6 made of an extremely thin film such as platinum is formed on the conductive electrode surface of the other electrode substrate 1 ′ via a transparent conductive electrode film 2 ′. As a result, in FIG. 1, the upper electrode substrate 1 'becomes the positive electrode, and the lower electrode substrate 1 becomes the negative electrode. Further, the electrode substrate 1 'is provided with two through holes 12a for injecting the electrolyte solution 5 into the sealed gap. The through holes 12a are sealed by the elastic hardening body 12, and The electrolyte solution 5 is injected in a state where an electrolyte solution injection needle (not shown) is passed through the elastic cured body 12, and the electrolyte solution 5 is sealed (sealed). Further, the elastic cured body 12 is sealed with a cover material 9 such as thin glass using a seal material 8.

  The electrode substrate 1, 1 'in the dye-sensitized solar cell of the present invention is preferably transparent, for example, an inorganic substrate made of white plate glass, soda glass, borosilicate glass, ceramics, etc., polyethylene (PE) , Polypropylene (PP), polyester, nylon, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), resinous substrates such as vinyl chloride, silicone resin, polycarbonate, polyimide, and organic-inorganic hybrid substrates. Among these, an inorganic substrate is preferable from the viewpoint of heat resistance and the like.

  Examples of the transparent conductive electrode films 2 and 2 'include indium-tin composite oxide (ITO), tin oxide doped with fluorine (FTO), tin oxide doped with antimony (ATO), and tin oxide. Used. These may be used alone or in combination of two or more.

  As the porous semiconductor film 3 formed on the negative electrode substrate 1 through the transparent conductive electrode film 2, for example, a porous n-type metal oxide semiconductor made of titanium oxide or the like is preferable.

  Examples of the sensitizing dye 4 adsorbed on the porous semiconductor film 3 include a sensitizing dye that absorbs sunlight having a wavelength of 300 to 2000 nm and adsorbs on the porous semiconductor film 3. Examples of the material of the sensitizing dye 4 include organic dyes such as ruthenium complex, porphyrin, phthalocyanine, merocyanine, coumarin, and indoline.

  On the other hand, examples of the conductive film 6 formed on the positive electrode substrate 1 ′ via the transparent conductive electrode film 2 ′ include an ultrathin film of platinum, carbon, or the like. This improves the hole mobility in the electrode substrate 1 '. Among these, a platinum vapor deposition film is more preferably used. Note that the conductive film 6 may be omitted.

  The electrolyte solution 5 sealed in the gap between the electrode substrates 1 and 1 'is a liquid containing an electrolyte, and is composed of an electrolyte and a liquid solvent. Examples of the electrolyte include iodine. Examples of the liquid solvent include ethylene carbonate, acetonitrile, methoxypropionitrile, and the like, and an electrolyte solution is prepared by mixing tetrapropylammonium iodide, lithium iodide, iodine, and the like.

  Here, in the dye-sensitized solar cell of the present invention, a through hole is formed in at least a part of the electrode substrate, and the through hole is sealed with an elastic cured body, and an electrolyte solution is injected into the elastic cured body. The most important feature is that the electrolyte solution is injected in a state in which the needle is penetrated. In FIG. 1, two through holes 12 a for injecting the electrolyte solution 5 into the sealed gap are provided in the electrode substrate 1 ′. The through holes 12 a are sealed by the elastic hardening body 12. Yes. In the present invention, the electrolyte solution 5 is injected in a state where an electrolyte solution injection needle (not shown) is passed through the elastic cured body 12, and when the electrolyte solution injection needle is pulled out, The hole of the needle is automatically closed by the elastic force of the elastic cured body 12, and the electrolyte solution is sealed.

  The elastic cured body 12 is preferably a three-dimensionally cross-linked thermosetting elastomer elastic cured body, for example, a silicone sealing material, a modified silicone sealing material, a fluorine-based polymer sealing material, an acrylic urethane sealing material, and a polyisobutylene sealing material. And an elastomer cured body of at least one sealing material selected from the group.

  Examples of the silicone sealant include moisture curable alkoxysilyl group-containing polydimethylsiloxane, and examples of the modified silicone sealant include polyether containing an alkoxysilyl group at the terminal. Examples of the fluorine-based polymer sealing material include a thermosetting fluorosilicone body with a hydroxysilylated and terminal-unsaturated polydimethylsiloxane perfluoropolyether copolymer at the terminal, and the acrylic urethane sealing material includes: Examples thereof include isocyanate-curing hydroxyl group-containing acrylic polymers, and examples of the polyisobutylene sealing material include hydroxysilylated and terminally unsaturated polyisobutylenes having terminal ends and alkoxyl group-containing polyisobutylenes.

  In FIG. 1, the elastic cured body 12 is sealed with a cover material 9 such as flake glass using a sealing material 8 in order to protect it from hail, wind, rain and the like.

  As the sealing material (end sealing material) 8, for example, the same material as the photopolymerizable composition used for the sealing material 7 can be used.

  Here, the manufacturing method of the dye-sensitized solar cell of this invention is demonstrated. Specifically, as shown in FIG. 1, an electrode substrate 1 with a transparent conductive electrode film 2 is prepared, and, for example, a titanium oxide paste of 5 to 50 μm is formed on the conductive electrode surface (electrolyte side) of the electrode substrate 1. The porous semiconductor film 3 is formed by coating with a thickness and baking at 400 to 600 ° C. for 0.5 to 3 hours. Next, the electrode substrate 1 on which the porous semiconductor film 3 is formed is immersed in an ethanol solution of the sensitizing dye 4 whose concentration is adjusted. Then, the excess sensitizing dye 4 is removed by immersing in absolute ethanol, and the porous semiconductor film 3 to which the sensitizing dye 4 is adsorbed is obtained by drying. Next, a surface coating treatment is performed on the portion of the electrode substrate 1 in contact with the sealing material 7 using a silane coupling agent. This surface coating treatment is performed, for example, by dissolving the silane coupling agent in an organic solvent such as methanol or ethanol in the range of 0.01 to 5.0% by weight to the electrode substrate 1 portion in contact with the sealing material 7. It is performed by coating and heating in the range of 60 to 150 ° C.

  Also, an electrode substrate 1 ′ with a transparent conductive electrode film 2 ′ is prepared, and a conductive film 6 such as a platinum vapor deposition film is deposited on the conductive electrode surface (electrolyte side) on the electrode substrate 1 ′ by sputtering or the like. . For example, two holes 12a are formed in the electrode substrate 1 'with a diamond drill or the like. Next, the through-hole 12a is filled with a sealing material (for example, silicone sealing material) for the elastic cured body 12, and is left in the room to seal the through-hole 12a with a cured body of the sealing material. . After that, the elastic cured body (for example, elastomer cured body) 12 is shaped so that there are no irregularities on the surface, the electrode substrate 1 '(glass surface) and the elastic cured body 12 are smoothed, and toluene and methanol are used. The electrode substrate 1 ′ (glass surface) and the conductive film 6 (platinum surface) are cleaned. Then, similarly to the electrode substrate 1, a silane coupling agent is applied to the electrode substrate 1 ′ that is in contact with the sealing material 7 and surface-treated.

Next, the photopolymerizable composition prepared in the same manner as described above is applied to at least one predetermined part of the electrode substrates 1 and 1 'to form an uncured material of the seal material 7. Then, with the conductive electrode surface facing inward, the electrode substrates 1 and 1 'are bonded together with the sealing material 7, and irradiated with an irradiation intensity of 0.5 to 10000 mW / cm ² using an ultraviolet irradiation device such as a high-pressure mercury lamp. Under the condition of time of 0.5 to 600 seconds, it is cured by ultraviolet irradiation (preferably in a nitrogen atmosphere) to perform main sealing.

  Next, a needle (injection needle) of a syringe (injection cylinder) containing the electrolyte solution 5 is passed through the elastic cured body 12 in which one through hole 12a of the electrode substrate 1 'is sealed. Further, only the needle is inserted into the hardened body 12 portion of the silicone sealing material filled in the other through hole 12a of the electrode substrate 1 'as air vent. And by pushing in the said syringe, the electrolyte solution 5 is inject | poured into the space | gap between the said electrode substrates 1 and 1 'through a needle, After injection | pouring of the electrolyte solution 5 is complete | finished, a needle is pulled out from an injection port. Further, a cover material 9 such as glass flakes coated with a photopolymerizable composition similar to the photopolymerizable composition for the main sealing material is placed, and in the same manner as described above, the composition is sealed by irradiation with ultraviolet rays to cure the composition ( End seal). In this way, the dye-sensitized solar cell shown in FIG. 1 can be obtained.

  The sealing material or the like in the dye-sensitized solar cell of the present invention can be appropriately used in an appropriate thickness (between substrates) and width depending on the purpose and application. Usually, the width is about 1 to 5 mm and the thickness is 50. It is preferable that it is -500 micrometers.

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

[Example 1]
(Preparation of negative electrode substrate)
A titanium oxide paste is screen-printed on one surface of a borosilicate glass plate with a fluorine-doped transparent conductive electrode film (size: 26 mm × 76 mm × thickness 1.3 mm), and then baked at 500 ° C. for 1 hour to obtain a thickness of 8 to A 12 μm semiconductor film was produced. Next, this semiconductor film was once immersed in an ethanol solution of a ruthenium-based sensitizing dye (manufactured by Solaronix, ruthenium 535 dye) and washed with absolute ethanol to adsorb the dye. Further, a 1 wt% methanol solution of 3-acryloxypropyltrimethoxysilane is applied to the main seal coating portion around the seal material and dried at 100 ° C. for 10 minutes, and the surface is coated with a silane coupling agent. A coated negative electrode substrate was prepared.

(Preparation of positive electrode substrate)
Two holes (diameter 2 mm) were opened with a diamond drill in a borosilicate glass plate with a platinum film (size: 26 mm × 76 mm × thickness 1.3 mm). Next, a silicone sealing material (Cemedine 8060, manufactured by Cemedine Co., Ltd.) was filled in the through hole, and then left in the room, and the through hole was sealed with a cured body of the silicone sealing material. Then, it shape | molded so that the unevenness | corrugation of the surface of the said hardening body might be eliminated, and while smoothing the glass surface and the hardening body surface, the glass surface and the platinum surface were wash | cleaned with toluene and methanol. Next, a 1 wt% methanol solution of 3-acryloxypropyltrimethoxysilane is applied to the main seal coating portion around the seal material and dried at 100 ° C. for 10 minutes. A positive electrode substrate subjected to surface coating treatment was prepared.

(Preparation of dye-sensitized solar cell)
With the conductive electrode surfaces of the negative electrode substrate and the positive electrode substrate facing inside, the photopolymerizable composition was applied at a distance of 50 μm (50 μm polyimide tape was used as a spacer), under a nitrogen stream, Ultraviolet curing was performed under conditions of an integrated light quantity of 3000 mJ / cm ² , and the negative electrode substrate and the conductive electrode surface of the positive electrode substrate were bonded together to perform main sealing.

Next, an electrolyte solution [composition: I ₂ (0.1 mol / L), 4-t-butylpyridine (0.5 mol / L) is applied to the cured elastomer having one through hole of the positive electrode substrate sealed. The needle (injection needle, diameter 0.4 mm) of a syringe (injection cylinder) containing the acetonitrile solvent] was passed through. Moreover, only the needle (diameter 0.4 mm) was inserted into the cured elastomer having the other through hole of the positive electrode substrate sealed as air. Thereafter, the syringe was pushed in to inject the electrolyte solution into the gap between the electrode substrates through the needle. After the injection of the electrolyte solution was completed, the needle was pulled out from the injection port. At this time, there was no leakage from the electrolyte solution inlet. Further, a thin glass coated with a photopolymerizable composition similar to the photopolymerizable composition for the main sealing material is placed, and UV-cured under a condition of an integrated light quantity of 3000 mJ / cm ² under a nitrogen stream, and an end seal is formed. The dye-sensitized solar cell was manufactured.

[Example 2]
Instead of the silicone sealing material for the cured elastomer of Example 1 (Cemedine, Cemedine 8060), a fluorine-based polymer sealing material (Shin-Etsu Chemical Co., Ltd., SIFEL8370A / B solution, two-component heat curing type) was used. . Other than that, the dye-sensitized solar cell was produced according to the manufacturing method of Example 1.

Example 3
Instead of the silicone sealing material for the cured elastomer of Example 1 (Cemedine, Cemedine 8060), a polyisobutylene sealing material (Kaneka, Epion S type, room temperature condensation curable type) was used. Other than that, the dye-sensitized solar cell was produced according to the manufacturing method of Example 1.

[Comparative Example]
A dye-sensitized solar cell having a structure in which the electrolyte solution is injected into the sealed (main sealed) gap as shown in FIG. 2 from the injection port and then the injection port is sealed (end seal) was produced. .

(Preparation of negative electrode substrate)
A negative electrode substrate was prepared in the same manner as in Example 1.

(Preparation of positive electrode substrate)
As shown in FIG. 2, a positive electrode substrate was prepared in substantially the same manner as in Example 1 except that it had an electrolyte solution inlet (opening).

(Preparation of dye-sensitized solar cell)
With the conductive electrode surfaces of the negative electrode substrate and the positive electrode substrate facing inside, the photopolymerizable composition was applied at a distance of 50 μm (50 μm polyimide tape was used as a spacer), under a nitrogen stream, Ultraviolet curing was performed under conditions of an integrated light quantity of 3000 mJ / cm ² , and the negative electrode substrate and the conductive electrode surface of the positive electrode substrate were bonded together to perform main sealing. Next, an electrolyte solution similar to that in Example 1 was injected from the injection port (opening portion) of the positive electrode substrate bonded together. Further, a thin glass coated with a photopolymerizable composition similar to the photopolymerizable composition for the main sealing material is placed, and UV-cured under a condition of an integrated light quantity of 3000 mJ / cm ² under a nitrogen stream, and an end seal is formed. The dye-sensitized solar cell was manufactured.

  Using the dye-sensitized solar cells of Examples and Comparative Examples thus obtained, the electrolyte solution filling retention was measured according to the following criteria. The results are shown in Table 1 below.

[Electrolytic solution filling retention]
Each of the obtained dye-sensitized solar cells was left in a high-temperature dryer at 85 ° C. for 500 hours to determine the electrolyte solution filling retention rate, and the leakage of the electrolyte solution was evaluated. Moreover, when there was leakage of the electrolyte solution, the leakage portion was visually observed.

  From the results shown in Table 1, the product of the example was excellent in durability without leakage of the electrolyte solution of the battery cell even after being left for 500 hours. Even when a modified silicone sealant, an acrylic urethane sealant, or a polyisobutylene sealant is used in place of the silicone sealant for the cured elastomer of Example 1, the same excellent effect as in Example 1 can be obtained. The present inventors have confirmed that.

  On the other hand, the comparative example product had an electrolyte solution filling retention rate of 84%, and 16% of the electrolyte solution leaked from the inlet, resulting in poor durability. In the comparative example product, the seal material (end seal material) comes into contact with the electrolyte solution in an uncured state, and the components of the seal material are eluted into the electrolyte solution by the solvent used in the electrolyte solution. This is probably because the electrolyte solution leaks.

  The dye-sensitized solar cell of the present invention can prevent elution of the sealing material component by the electrolyte solution, does not swell or deteriorate during long-term sealing, has extremely high sealing performance, and is excellent in reliability and durability. ing.

1, 1 'electrode substrate 5 electrolyte solution 8 sealing material 12a through-hole 12 elastic hardened body

Claims (3)

  A dye-sensitized solar cell in which a pair of electrode substrates are bonded and sealed facing each other, and an electrolyte solution is injected into the sealed gap, and at least a part of the electrode substrate penetrates for injection of the electrolyte solution A hole is formed, the through hole is sealed with an elastic cured body, and the electrolyte solution is injected in a state in which the electrolyte solution injection needle is passed through the elastic cured body. Sensitive solar cell.   The elastic cured body comprises an elastomer cured body of at least one sealing material selected from the group consisting of a silicone sealing material, a modified silicone sealing material, a fluorine-based polymer sealing material, an acrylic urethane sealing material, and a polyisobutylene sealing material. 1. The dye-sensitized solar cell according to 1.   3. The method for producing a dye-sensitized solar cell according to claim 1, wherein a through hole formed in the electrode substrate is sealed with an elastic cured body, and then an electrolyte solution injection needle is attached to the elastic cured body. A method for producing a dye-sensitized solar cell, which penetrates and injects the electrolyte solution.

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