JP5344282B2 - Dye-sensitized solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dye-sensitized solar cell having high durability, even when an electrolyte having high corrosion resistance such as iodine. <P>SOLUTION: A photoelectrode substrate including a first substrate, a conductive layer formed on the inner surface of the first substrate, and an oxide semiconductor layer formed on the conductive layer and carrying dye, and a counter electrode substrate including a second substrate and a conductive layer formed on the inner surface of the second substrate are laminated so that the oxide semiconductor layer and the conductive layer of the counter electrode substrate are countered, and a sealed container filled with an electrolyte is placed between the photoelectrode substrate and the counter electrode substrate. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a dye-sensitized solar cell, and more particularly, to a dye-sensitized solar cell excellent in product durability.

  In recent years, environmental problems such as global warming have been pointed out worldwide, and solar power generation has attracted attention as clean energy with a low environmental load, and active research and development of solar cell elements has been promoted. As solar cells, single crystal silicon solar cells, polycrystalline silicon solar cells, amorphous silicon solar cells, compound semiconductor solar cells, etc. have already been put into practical use, but there are problems in manufacturing costs and energy consumption at the manufacturing stage is large. Such a problem has been pointed out. From such a viewpoint, a dye-sensitized solar cell has begun to attract attention as a novel solar cell that can be manufactured at a relatively low cost and can reduce energy consumption at the manufacturing stage.

  In general, a dye-sensitized solar cell includes a transparent substrate, a transparent electrode (first electrode layer), an oxide semiconductor layer carrying a dye sensitizer, an electrolyte layer made of an electrolyte, from the light incident side, And a cell structure in which a counter electrode substrate including a second electrode layer is sequentially laminated. The electrolyte layer is filled with an electrolytic solution.

In a dye-sensitized solar cell, the electrolyte is formed with a hole in either the counter electrode substrate or the transparent electrode substrate, and the periphery of the second electrode substrate and the transparent electrode substrate is sealed with an adhesive or the like Then, it is generally filled by a method of injecting from the hole (Japanese Patent Laid-Open No. 2004-319112: Patent Document 1). Further, a method has been proposed in which an electrolytic solution is made into a paste and applied directly onto a transparent electrode (International Publication WO2005 / 006482: Patent Document 2). In some cases, iodine / iodide ions are added to these electrolytic solutions as a redox pair.
JP 2004-319112 A International Publication No. WO2005 / 006482

  The dye-sensitized solar cell generates photovoltaic power by receiving light from the time when the electrolyte is injected as described above and the assembly of the cell is completed. Therefore, after the dye-sensitized solar cell is manufactured, the photoelectric conversion reaction proceeds by light reception until the user actually uses it. In particular, when a highly corrosive electrolytic solution containing iodine or the like is used as the electrolytic solution, deterioration of the power generation member is promoted and the product life is further shortened. Therefore, when a long time is required from the production to use, the durability of the solar cell sometimes becomes a problem.

  Accordingly, an object of the present invention is to provide a dye-sensitized solar cell that is excellent in durability even when a highly corrosive electrolyte such as iodine is used.

  Another object of the present invention is to provide a method for producing the dye-sensitized solar cell.

A dye-sensitized solar cell according to the present invention includes a first substrate, a conductive layer provided on an inner surface of the substrate, and a photoelectrode provided with an oxide semiconductor layer supporting a dye provided on the conductive layer. A substrate, a second substrate and a counter electrode substrate provided with a conductive layer provided on the inner surface of the substrate, are stacked such that the oxide semiconductor layer and the conductive layer of the counter electrode substrate are opposed to each other,
An airtight container filled with an electrolyte is provided between the photoelectrode substrate and the counter electrode substrate.

  The present invention also provides a dye-sensitized solar cell module in which a plurality of the dye-sensitized solar cells are connected.

  In the present invention, the electrolyte solution injected between the photoelectrode substrate and the counter electrode substrate is incorporated in the dye-sensitized solar cell in a state where it is filled in a sealed container. By crushing the sealed container, the electrolytic solution is filled between the photoelectrode substrate and the counter electrode substrate. Therefore, even after the assembly of the cell is completed, the constituent members are not deteriorated by the electrolyte unless the sealed container is crushed. In addition, since the electrolytic solution is not filled between the photoelectrode substrate and the counter electrode substrate from manufacture to use, a photoelectric conversion reaction does not occur even by light reception. As a result, a dye-sensitized solar cell with excellent durability can be realized even when it takes a long time to be used after being manufactured.

<Dye-sensitized solar cell>
The dye-sensitized solar cell according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic sectional view of a dye-sensitized solar cell according to the present invention. The dye-sensitized solar cell according to the present invention includes a first substrate 1, a conductive layer 2 provided on the inner surface of the substrate 1, and an oxide semiconductor layer 3 supporting a dye provided on the conductive layer 2. A counter electrode substrate including the second substrate 6 and the conductive layer 5 provided on the inner surface of the substrate 6, the oxide semiconductor layer 3, and the conductive layer 5 of the counter electrode substrate Are arranged so as to face each other, and a sealed container 7 filled with an electrolytic solution 8 is provided between the photoelectrode substrate and the counter electrode substrate. As a more preferable aspect of the present invention, it is preferable that the catalyst layer 4 is provided on the conductive layer 5 provided on the inner surface of the second substrate 6.

  The 1st board | substrate 1 and the 2nd board | substrate 6 are mutually bonded by the adhesive bond layer 9, and form the cell. When the cell having the above structure is assembled, there is no electrolyte between the photoelectrode substrate and the counter electrode substrate. As shown in FIG. 2, after the cell is assembled, when pressure is applied to the substrates 1 and 2 on both sides of the dye-sensitized solar cell, an external pressure is applied to the sealed container 7 and the sealed container 7 is crushed and electrolyzed outside the container Liquid 8 leaks out. The leaked electrolyte solution is filled between the oxide semiconductor layer 3 and the catalyst layer 4, and a photoelectric conversion reaction occurs due to light reception to generate photovoltaic power. The first substrate and / or the second substrate is preferably made of a flexible material so that an external pressure is easily applied to the sealed container.

  Next, each member which comprises the dye-sensitized solar cell by this invention is demonstrated.

<First substrate>
The first substrate used for the photoelectrode substrate is usually the light-receiving surface of the dye-sensitized solar cell element. Accordingly, the first substrate is preferably excellent in light transmission. In the present invention, the kind of the support is not particularly limited, and the same support as a general dye-sensitized solar cell element can be used. Specific examples thereof include glass, non-plastic rigid material, and flexible film base material, but are not limited thereto. Examples of the rigid material include quartz glass, Pyrex (registered trademark), and a synthetic quartz plate.

  In the present invention, as described above, the electrolytic solution in the sealed container is released by applying external pressure to the container and crushing it. Therefore, it is preferable that the base material is made of a flexible material so that external pressure can be easily applied to the sealed container. Examples of film substrates include ethylene / tetrafluoroethylene copolymer films, biaxially stretched polyethylene terephthalate films, polyethersulfone (PES) films, polyetheretherketone (PEEK) films, and polyetherimide (PEI) films. , Polyimide (PI) film, polyester naphthalate (PEN), polycarbonate (PC) resin film substrate, etc., among others, biaxially stretched polyethylene terephthalate film (PET), polyester naphthalate (PEN), polycarbonate (PC) is preferred. The film substrate is excellent in processability and can reduce the manufacturing cost.

  Moreover, the said base material may be used individually by 1 type, and may laminate | stack and use 2 or more types.

  Although the thickness of a base material is not specifically limited, About 12-200 micrometers is preferable from a viewpoint of the intensity | strength of a base material and workability.

<Conductive layer>
The conductive layer provided on the first substrate has a function of collecting charges generated by light irradiation. Therefore, the conductive layer is preferably excellent in light transmittance and conductivity. In the present invention, the type of the conductive layer and the like are not particularly limited, and those similar to general dye-sensitized solar cell elements can be used.

The conductive layer is usually made of a metal oxide. Examples of the metal oxide include SnO ₂ , FTO (fluorine-doped tin oxide), ATO (antimony-doped tin oxide), ITO, and ZnO. Of these, FTO and ITO are preferable. This is because FTO and ITO are excellent in light transmission and conductivity.

  The conductive layer may have a single layer structure or a multilayer structure. As the conductive layer having a multilayer structure, for example, a layer in which layers having different work functions are stacked, a layer in which different metal oxide layers are stacked, and the like can be given.

  Although it does not specifically limit as thickness of the said conductive layer, For example, it is preferable to exist in the range of 5 nm-2000 nm, especially in the range of 10 nm-1000 nm. If the thickness of the conductive layer is too small, sufficient conductivity may not be obtained. If the thickness of the conductive layer is too large, it may be difficult to form a homogeneous conductive layer. is there.

<Oxide semiconductor layer>
The oxide semiconductor layer is a porous layer formed on the conductive layer and generally containing a dye sensitizer. In the present invention, the type and the like of the oxide semiconductor layer are not particularly limited, and those similar to general dye-sensitized solar cell elements can be used.

The oxide semiconductor layer usually contains metal oxide semiconductor fine particles. Examples of the metal oxide semiconductor fine particles include TiO ₂ , ZnO, SnO ₂ , ITO, ZrO ₂ , MgO, Al ₂ O ₃ , CeO ₂ , Bi ₂ O ₃ , Mn ₃ O ₄ , Y ₂ O ₃ , WO ₃ , Ta ₂ O ₅ , Nb ₂ O ₅ , La ₂ O _{3 and the} like, and TiO ₂ is particularly preferable. Since these metal oxide semiconductor fine particles are suitable for forming a porous oxide semiconductor layer, they are preferably used. The metal oxide semiconductor fine particles may have a core-shell structure. Furthermore, the oxide semiconductor layer may be one using the metal oxide semiconductor fine particles, or may be two or more types.

  The particle size of the metal oxide semiconductor fine particles is not particularly limited, but is preferably in the range of, for example, 1 nm to 10 μm, and more preferably in the range of 10 nm to 1000 nm. If the particle size of the metal oxide semiconductor fine particles is too small, the respective metal oxide semiconductor fine particles may aggregate to form secondary particles. If the particle size of the metal oxide semiconductor fine particles is too large, the oxide semiconductor This is because the layer may be thickened and the film resistance may be increased.

  On the other hand, the oxide semiconductor layer usually carries a dye sensitizer. The dye sensitizer is not particularly limited, and examples thereof include organic dyes and metal complex dyes. Specific examples of the organic dyes include acridine dyes, azo dyes, indigo dyes, quinone dyes, coumarin dyes, merocyanine dyes, and phenylxanthene dyes. Of these, coumarin dyes are preferable. On the other hand, specific examples of the metal complex dye include a ruthenium dye, and among them, a ruthenium bipyridine dye and a ruthenium terpyridine dye, which are ruthenium complexes, are preferable.

  Although it does not specifically limit as thickness of the said oxide semiconductor layer, For example, it is preferable to exist in the range of 1 micrometer-100 micrometers, especially in the range of 5 micrometers-30 micrometers. If the thickness of the oxide semiconductor layer is too small, it may be difficult to form an oxide semiconductor layer having a uniform thickness. If the thickness of the oxide semiconductor layer is too large, the oxide semiconductor layer film This is because the resistance may increase.

<Electrolyte>
The electrolytic solution is provided between the oxide semiconductor layer described above and a counter electrode substrate described later. The electrolytic solution has a function of charge transport between the dye sensitizer carried on the oxide semiconductor layer and the counter electrode layer.

  As the electrolytic solution, the same one as a general dye-sensitized solar cell element can be used. Specifically, propylene carbonate, iodine, N-methylbenzimidazole, guanidinium thiocyanate, lithium iodide. An electrolytic solution in which is dissolved can be preferably used.

  The electrolytic solution contains a redox pair. Examples of the oxidation-reduction pair include iodine-iodine compounds and bromine-bromine compounds used in the dye-sensitized solar cell electrolyte as described above.

  The form of the electrolytic solution is not particularly limited as long as it can perform charge transport, and a liquid form, a solid form, or a semisolid form can be used. When the electrolytic solution is in a liquid state, it is preferable to dispose an electrical insulating layer between the oxide semiconductor layer and the counter electrode substrate in order to prevent a short circuit due to contact between the photoelectrode substrate and the counter electrode substrate.

  As the electrical insulating layer, those used for general dye-sensitized solar cells can be used, and for example, Hypore (Asahi Kasei Chemicals) and the like can be preferably used.

<Counter electrode substrate>
The counter electrode substrate has a structure including a second substrate and a conductive layer provided on the inner surface of the substrate, and is provided to face the above-described oxide semiconductor layer. In the present invention, the type and the like of the counter electrode substrate are not particularly limited, and those similar to a general dye-sensitized solar cell element can be used. In addition, as the counter electrode substrate, a material similar to that obtained by providing a conductive layer on the first substrate described above can be used. Furthermore, in the present invention, the counter electrode substrate preferably has a metal having a function as a catalyst layer, such as Pt, C, or a conductive polymer, on the surface of the oxide semiconductor layer.

  The dye-sensitized solar cell element used in the present invention is formed by laminating the above constituent members. The shape of the dye-sensitized solar cell element is not particularly limited, and examples thereof include a strip shape, a circular shape, and a spiral shape.

<Sealed container>
Any container may be used as the sealed container filled with the electrolytic solution as long as it can be crushed by external pressure. For example, after superposing two resin films and further sealing the periphery of the outer periphery with a form such as a three-side seal type, an unsealed container having an opening in a part is first formed, and then an electrolytic solution is passed through the opening After injecting, the resin film peripheral edge of the opening is sealed in the same manner as described above to form a sealed container filled with the electrolytic solution.

  As a material for the container, a resin film can be generally used. For example, a low-density polyethylene resin, a medium-density polyethylene resin, a high-density polyethylene resin, a linear low-density polyethylene resin, a polypropylene resin, and ethylene-vinyl acetate are used. Polymer resin, ionomer resin, acrylic resin, ethylene-acrylic acid copolymer resin, ethylene-ethyl acrylate copolymer resin, ethylene-methacrylic acid copolymer resin, ethylene-propylene copolymer resin, methylpentene resin A film made of a resin such as a polybutene resin, an acid-modified polyolefin resin, or a urethane resin can be suitably used.

  Moreover, when using an electrolytic solution containing iodine as described above as the electrolytic solution, it is preferable to use a resin that does not corrode or dissolve the sealed container by the electrolytic solution.

<Dye-sensitized solar cell module>
The dye-sensitized solar cell module according to the present invention has a structure in which a plurality of dye-sensitized solar cells are arranged and connected. Connection of each battery may be connected in series, or may be connected in parallel.

  Hereinafter, although an example and a comparative example explain the present invention still in detail, the present invention is not limited to these examples.

<Production of photoelectrode substrate>
Transparent conductive glass (manufactured by Nippon Sheet Glass) with an FTO film on a glass plate is prepared, and titanium oxide paste (Nanoxide D-SP, manufactured by Solaronix) is applied to this substrate in the range of 4 mm x 4 mm by screen printing. And an oxide semiconductor layer having a thickness of 7 μm was formed by baking at 500 ° C. Next, as a sensitizing dye, a ruthenium complex (N719, manufactured by Dyesol) was mixed in a mixed solution of acetonitrile and tert-butyl alcohol (volume ratio 1: 1) so that the concentration was 3 × 10 ₋₄ mol / l. A dissolved dye-supporting composition was prepared, and the FTO-glass substrate provided with the oxide semiconductor layer was immersed in this composition for 24 hours to support the sensitizing dye on the porous oxide semiconductor layer. I let you. Thereafter, the substrate provided with the porous oxide semiconductor layer is pulled up from the dye supporting composition, the dye supporting composition attached to the porous oxide semiconductor layer is washed with acetonitrile, and dried in an Ar purged glove box. It was. Thus, an electrode substrate having a porous oxide semiconductor layer and a catalyst layer formed on a conductive layer was produced.

<Preparation of counter electrode substrate>
After laminating ITO on a polyethylene terephthalate (PET) substrate by sputtering so that the surface resistance value is 25 Ω / □, platinum is laminated on the ITO film so as to have a thickness of 20 mm. did.

<Preparation of electrolyte>
For 10 ml of propylene carbonate (made by Junsei Kagaku), iodine (made by Merck) 0.2 mol / l, N-methylbenzimidazole (made by Aldrich) 0.5 mol / l, guanidinium thiocyanate (made by Aldrich) 0.1 mol / l 1 and 2 mol / l of lithium iodide (manufactured by Wako) were dissolved to prepare an electrolytic solution.

  This electrolyte solution was poured into a bag container sealed with a 50 μm-thick ionomer resin film on three sides, and the bag container was sealed by sealing the opening.

<Cell assembly>
An ionomer resin sheet having a thickness of 30 μm is laminated on the platinum layer of the counter electrode substrate with a width of 1 mm so as to surround the porous oxide semiconductor layer, and the above sealed bag container is placed therein, and porous oxidation is performed. The photoelectrode substrate was bonded so that the physical semiconductor layer and the platinum layer were opposed to each other and heated on a hot plate at 100 ° C. to bond both substrates to obtain a dye-sensitized solar cell.

<Performance evaluation of solar cells>
The photoelectric conversion efficiency was measured when the obtained solar cell was irradiated with light from the photoelectrode substrate side using AM1.5 and pseudo-sunlight (incident intensity 100 mW / cm ² ) as a light source. Conversion efficiency was measured using a solar simulator (CEP2000, manufactured by Spectrometer Co., Ltd.). As a result, the conversion efficiency was 0%.

  Thereafter, pressure was applied by hand to both the substrates of the dye-sensitized solar cell to crush the sealed bag container in the cell and leak the electrolyte into the cell. The conversion efficiency at that time was 2.04%.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic sectional drawing of the dye-sensitized solar cell by this invention (before airtight container crushing) is shown. BRIEF DESCRIPTION OF THE DRAWINGS The schematic sectional drawing of the dye-sensitized solar cell (after airtight container crushing) by this invention is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st board | substrate 2 Conductive layer 3 Oxide semiconductor layer 4 Catalyst layer 5 Conductive layer 6 2nd board | substrate 7 Airtight container 8 Electrolytic solution 9 Adhesive layer

Claims (7)

A first substrate, a conductive layer provided on an inner surface of the substrate, a photoelectrode substrate provided with an oxide semiconductor layer carrying a dye provided on the conductive layer, and a second substrate and an inner surface of the substrate And a counter electrode substrate provided with a conductive layer provided on the oxide semiconductor layer and the conductive layer of the counter electrode substrate are stacked so as to face each other,
Between the photoelectrode substrate and the counter electrode substrate, comprising a sealed container filled with an electrolyte,
The sealed container can be crushed by external pressure,
Before the airtight container is crushed, there is no electrolyte other than inside the airtight container . The dye-sensitized solar cell according to claim 1 , wherein the sealed container is made of a resin film. The dye-sensitized solar cell according to claim 1 or 2 , wherein the first substrate and the second substrate are made of a flexible material. The dye-sensitized solar cell according to any one of claims 1 to 3 , wherein the first substrate and / or the second substrate are transparent.   The dye-sensitized solar cell according to any one of claims 1 to 4, wherein a catalyst layer is provided on the conductive layer provided on the inner surface of the second substrate. The dye-sensitized solar cell according to any one of claims 1 to 5 , wherein the conductive layer is formed of a transparent material. A dye-sensitized solar cell module in which a plurality of the dye-sensitized solar cells according to any one of claims 1 to 6 are connected.

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