JP5128118B2 - Wet solar cell and manufacturing method thereof - Google Patents

Description

  The present invention is abbreviated as a dye-sensitized solar cell [hereinafter DSC (Dye-Sensitized Solar Cell). In particular, the present invention relates to a structure that improves the characteristics of a wet solar cell in which metal wiring for current collection is provided.

  Against the backdrop of environmental problems and resource problems, solar cells as clean energy are attracting attention. Typical solar cells include those using single crystal, polycrystalline or amorphous silicon. However, conventional silicon-based solar cells are not widely used because they are expensive to manufacture and have problems such as insufficient supply of raw materials and are difficult to provide at low cost.

On the other hand, DSC has been proposed by a group such as Gretzel of Switzerland, and has attracted attention as a photoelectric conversion element that can be obtained at low cost and high photoelectric conversion efficiency.
In general, wet solar cells such as DSC have a structure in which an electrolyte is sandwiched between a transparent window electrode into which light enters and a counter electrode made of a conductive glass substrate.
FIG. 11 is a schematic cross-sectional view showing an example of the structure of a conventional wet solar cell.
The DSC 100 includes a first substrate 101 having a porous semiconductor electrode 103 (hereinafter also referred to as a dye-sensitized semiconductor electrode) 103 carrying a sensitizing dye formed on one surface and a conductive film having a catalyst film 105 formed thereon. The main component is a porous second substrate 104 and an electrolyte layer 106 made of, for example, a gel electrolyte enclosed between them.

As the first base material 101, for example, a light transmissive plate material is used, and a transparent conductive film 102 is disposed on the surface of the first base material 101 in contact with the dye-sensitized semiconductor electrode 103 in order to provide conductivity. The window electrode 108 is constituted by the first base material 101, the transparent conductive layer 102, and the dye-sensitized semiconductor electrode 103.
On the other hand, as the second base material 104, for example, a catalyst layer 105 made of carbon or platinum is provided on the surface in contact with the electrolyte layer 106 in order to exchange charges with the electrolyte layer. The counter electrode 109 is configured by the 104 and the catalyst layer 105.
The first base material 101 and the second base material 104 are arranged at a predetermined interval so that the dye-sensitized semiconductor electrode 103 and the catalyst layer 105 face each other, and are made of a thermoplastic resin in the peripheral part between the two substrates. A sealing material 107 is provided. Then, the two substrates 101 and 104 are bonded together through the sealing material 107 and the cells are stacked, and an oxidation / reduction pair such as iodine / iodide ions is provided between the electrodes 108 and 109 through the electrolyte inlet 110. The electrolyte 106 for charge transfer is formed by filling the organic electrolyte solution.

  However, in the laboratory-type small wet solar cells, it is not necessary to consider the cell life. Therefore, the cell size is reduced, the window electrode and the counter electrode are tightened with screws, etc. Although conversion efficiency is obtained, in a practical wet solar cell, since it is necessary to seal both electrodes to prevent leakage of the electrolyte, the distance between the electrodes is increased by the amount of the sealing material.

  In addition, current collector wiring is required for large cells. This current collector wiring consists of a metal wiring and a wiring protective film. In order to achieve both conductivity and aperture ratio, it is desirable that the metal wiring be thin and thick, and ensure durability and reliability. Therefore, it is necessary to form the wiring protective film thickly. For this reason, the height of the current collecting wiring is often higher than the suitable height of the titanium oxide porous film constituting the porous oxide semiconductor layer, which causes the distance between the electrodes to increase. Since the distance between the electrodes greatly affects the photoelectric conversion efficiency, it is necessary to make it as small as possible. It is desirable that the distance between the titanium oxide porous film and the counter electrode is zero.

Thus, in order to obtain a dye-sensitized solar cell with as short an interelectrode distance as possible and a high photoelectric conversion efficiency, the following means has been proposed (see Patent Document 1).
(1) The counter electrode is subjected to uneven processing that conflicts with the current collector wiring portion, and the distance between the electrodes is reduced only in the portion where the porous oxide semiconductor layer exists.
(2) Using a flexible substrate bulging inward at the portion where the porous oxide semiconductor layer is formed on the counter electrode, pressurizing from the back surface, and using the counter electrode in a bent state between the electrodes Reduce distance.

  In addition, for the purpose of obtaining a dye-sensitized solar cell in which the distance between the working electrode (window electrode) and the counter electrode is kept constant, the working electrode and the counter electrode are stacked to form a laminate, and the working electrode and the counter electrode are formed. After filling the electrolyte solution for forming the electrolyte layer through the through hole provided in the counter electrode, after sealing one through hole and sucking out a part of the electrolyte solution from the other through hole A means for sealing the other through-hole and enclosing an electrolyte between the working electrode and the counter electrode has also been proposed (see Patent Document 2).

  Furthermore, the metal wiring layer is used for the purpose of obtaining a dye-sensitized solar cell excellent in photoelectric conversion efficiency by suppressing the shielding failure on the surface of the metal wiring layer and suppressing the circuit corrosion and reverse electron transfer caused by this. However, there is also proposed a means that is formed along a wiring pattern grooved in a transparent substrate, and at least a part of the metal wiring layer reaches a height below the surface of the transparent substrate (Patent Document). 3).

However, the means described in the above-mentioned Patent Document 1 must be provided with uneven processing and the like on the counter electrode side, which is inconsistent with the current collector wiring portion, which is complicated in structure and requires troublesome manufacturing. End up.
Further, in the means described in Patent Document 2, no measures are taken in the case of a configuration requiring current collecting wiring, and in a solar cell having a configuration requiring current collecting wiring, for the purpose of reducing the distance between the electrodes. The above technique cannot be easily applied.
Furthermore, the means described in Patent Document 3 also requires a groove processing for forming a metal wiring layer on the substrate, which is complicated in structure and requires troublesome manufacturing. End up.
JP 2005-346971 A JP 2005-353295 A JP 2004-146425 A

The present invention has been made in view of the above circumstances, and is a wet solar cell configured to include a current collector wiring, and without providing a special structure such as irregularities on the opposite surface side of both electrodes, the window electrode and the counter electrode It is a first object to provide a wet solar cell that can reduce the distance between the electrodes and the photoelectric conversion efficiency.
In addition, the present invention provides a wet solar cell in which the distance between the electrode between the window electrode and the counter electrode can be reduced with a simple structure without requiring a troublesome labor to provide a special structure such as irregularities on the opposite surface side of both electrodes. It is a second object to provide a manufacturing method.

A wet solar cell according to claim 1 of the present invention includes a porous oxide semiconductor layer carrying a sensitizing dye and is opposed to the first electrode that functions as a window electrode and the first electrode. A wet solar cell comprising: a second electrode disposed; and an electrolyte layer disposed in at least a portion between the first electrode and the second electrode, wherein the porous oxide semiconductor layer includes the first electrode Oite on a first substrate constituting a so clearance is provided between the metal wires, or are formed so as not provided gap, the first electrode, the metal wiring arranged region α is, the porous oxide semiconductor layer as compared to the region β, which is high, and wherein the protruding on the outer surface side of the first electrode.
A wet solar cell according to claim 2 of the present invention includes a porous oxide semiconductor layer carrying a sensitizing dye and is opposed to the first electrode that functions as a window electrode and the first electrode. A wet solar cell comprising: a second electrode disposed; and an electrolyte layer disposed in at least a portion between the first electrode and the second electrode, wherein the porous oxide semiconductor layer includes the first electrode The first electrode is provided at a position excluding the metal wiring formed on the first base material, and the region α in which the metal wiring is arranged is arranged in the porous oxide semiconductor layer. Compared to the region β, the first electrode protrudes to the outer surface side.

The wet solar cell according to claim 3 of the present invention is the wet solar cell according to claim 1 or 2 , wherein the substrate on which the porous oxide semiconductor layer is placed to constitute the first electrode is flexible. It is characterized by sex.

The wet solar cell according to claim 4 of the present invention is the wet solar cell according to any one of claims 1 to 3 , wherein a sealing resin material is provided on outer surfaces of the first electrode and the second electrode. The sheet material is arranged through.

A method for producing a wet solar cell according to claim 5 of the present invention comprises a porous oxide semiconductor layer carrying a sensitizing dye and a first electrode functioning as a window electrode, and the first electrode A second electrode disposed opposite to the first electrode, and an electrolyte layer disposed on at least a portion between the first electrode and the second electrode, and the porous oxide semiconductor layer is formed on the first electrode The first electrode has a region α in which the metal wiring is disposed, and the first electrode has a region β in which the porous oxide semiconductor layer is disposed in the region α. A method of manufacturing a wet solar cell protruding to the outer surface side of an electrode, wherein the second electrode is laminated on the first electrode, and then the pressure is applied from the outside or the inside is reduced in the lamination direction, The first electrode is bent.

In the wet solar cell according to the present invention, the porous oxide semiconductor layer constituting the first electrode functioning as the window electrode is provided at a position excluding the metal wiring formed on the first electrode. One electrode has a configuration in which the region α where the metal wiring is arranged protrudes to the outer surface side of the first electrode as compared with the region β where the porous oxide semiconductor layer is arranged. Therefore, the region β where the porous oxide semiconductor layer of the first electrode is disposed has a structure closer to the second electrode side which functions as a counter electrode than the region α where the metal wiring of the first electrode is disposed.
Therefore, even in a wet solar cell configured with current collecting wiring, it is possible to reduce the distance between the electrode between the window electrode and the counter electrode without providing a special structure such as unevenness on the opposite surface side of both electrodes. And a wet solar cell with improved photoelectric conversion efficiency can be provided.

In the method for manufacturing a wet solar cell according to the present invention, after laminating the second electrode functioning as the counter electrode on the first electrode functioning as the window electrode, by pressing from the outside or depressurizing the inside in the stacking direction, The first electrode is bent. Therefore, the region β where the porous oxide semiconductor layer of the first electrode is disposed can be brought closer to the second electrode side functioning as a counter electrode.
Therefore, in order to provide a special structure such as unevenness on the opposite surface side of both electrodes, a wet solar cell manufacturing method that can reduce the distance between the electrode between the window electrode and the counter electrode with a simple structure without requiring troublesome work. Can be provided.

Hereinafter, an embodiment of a wet solar cell according to the present invention will be described with reference to the drawings. However, the present invention is not limited to these embodiments as long as the above-described operation and effects are satisfied. .
The drawings shown below are not necessarily drawn to scale in order to facilitate understanding of the present invention.
FIG. 1 is a schematic cross-sectional view showing the structure of a wet solar cell according to the present invention.
As shown in FIG. 1, a wet solar cell (photoelectric conversion element) 1 according to this embodiment has a porous oxide semiconductor layer (also referred to as an oxide electrode) 13 having a sensitizing dye supported on its surface. A first electrode 10 configured and functioning as a window electrode (also called a working electrode), a second electrode 20 disposed to face the first electrode 10, and an electrolyte layer 30 on at least a part between these two electrodes And are arranged. Further, the wet solar cell 1 is provided at a position excluding the metal wiring 14 in which the porous oxide semiconductor layer 13 is formed on the first electrode 10, and the first electrode 10 is connected to the metal wiring 14. The region α in which is arranged is protruded to the outer surface side of the first electrode 10 as compared with the region β in which the porous oxide semiconductor layer 13 is arranged.

The first electrode 10 includes, for example, a first base material 11, a transparent conductive film 12 and a porous oxide semiconductor layer 13 that are sequentially disposed thereon. The first electrode 10 has conductivity to conduct electricity by forming a transparent conductive film (layer) 12 made of a conductive material on the surface of a first base material 11 made of a light transmissive material. A porous oxide semiconductor layer 13 is formed through the film 12. Furthermore, a current collecting wiring 16 having a metal wiring 14 with a gap is provided on the surface of the transparent conductive film 12 so as to sandwich the porous oxide semiconductor layer 13 from both sides. However, this gap is not essential, and a form in which a part of the porous oxide semiconductor layer 13 is present (covered) in the gap or the region where the metal wiring 14 is formed may be used.
Accordingly, the first electrode 10 includes a region α where the metal wiring 14 is disposed, a region β where the porous oxide semiconductor layer 13 is mainly disposed, and a gap located between the region α and the region β. And a region γ consisting of

The first base material 11 that is a part of the first electrode 10 serves as one electrode constituting a cell that accommodates an electrolyte, and also serves as a lid that constitutes the casing.
As the first base material 11 constituting the first electrode 10, a member having an optical characteristic that transmits sunlight is preferably used. As this 1st base material 11, the board | substrate which consists of transparent materials, such as a conductive resin film, thin conductive glass, and a metal mesh, is mentioned.
As the first base material 11, it is preferable to use a substrate made of a flexible material. As the substrate made of a flexible material, a substrate made of a synthetic resin is usually used. For example, a polyethylene terephthalate (PET) film, a polyethylene naphthalate (PEN) film, a polycarbonate (PC) film, or a polyethersulfone (PES). Examples of the substrate include a resin film such as a film, a metal thin plate, or a metal foil.

A transparent conductive film 12 that also transmits light and conducts electricity is formed on the surface of the first substrate 11. Transparent thin films with conductivity (referred to as transparent conductive films) include, for example, thin films made of indium oxide with several percent tin added, indium-tin-oxide (ITO) films, and oxides. Examples thereof include a thin film obtained by adding several percent of fluorine to tin, a fluorine-doped tin oxide (FTO) film, and the like. Such a transparent conductive film 12 is formed to a thickness of, for example, about 50 to 2000 nm.
In the ITO film, tetravalent tin (Sn ⁴⁺ ) substituted for trivalent indium (In ³⁺ ) ^sites generates carrier electrons, and thus the ITO film has a property of conducting electricity well. In addition, since the ITO film absorbs almost no visible light because the energy gap corresponds to the ultraviolet region, it also has the ability to transmit most of the visible light spectrum that constitutes sunlight.

  The transparent conductive film 12 is formed by a known method typified by a vacuum film formation method using a reduced-pressure atmosphere, such as a sputtering method or a vapor deposition method. From such a method, a film having excellent transparency and high conductivity can be obtained by using an appropriate method according to the material for forming the transparent conductive film 12.

A current collecting wiring 16 is further provided on the transparent conductive film 12. In order to improve the current collection efficiency from the porous oxide semiconductor layer 13 and the electrolyte layer 30, the current collection wiring 16 is provided, for example, on both sides of the porous oxide semiconductor layer 13 within a range that does not significantly impair the light transmittance. It is done.
The current collecting wiring 16 is composed of a metal wiring 14 and a wiring protection material 15 made of, for example, low melting point glass that covers the surface of the metal wiring 14 and protects the metal wiring 14 from corrosion by the electrolytic solution. The material of the metal wiring 14 used for the current collecting wiring 16 is not particularly limited, and for example, gold, silver, platinum, aluminum, nickel, titanium, or the like can be used. In addition, as a method of forming the metal wiring 14, for example, printing methods such as screen printing, metal mask, and ink jet, plating method, sputtering method, vapor deposition method and the like are not particularly limited, and various methods are used. Can do. Particularly preferably, a method including at least one of a plating method and a printing method is selected. The metal wiring 14 is formed in a pattern shape such as a stripe shape, a comb shape, or a lattice shape so that light can be transmitted through the first electrode as evenly as possible.

Then, the metal wiring 14 is covered with the wiring protective material 15 to constitute the current collecting wiring 16. The wiring protective material 15 preferably contains at least one of a glass component, a metal oxide component, or an electrochemically inactive resin component. Examples of the glass component include low-melting-point amorphous or crystalline glass components such as lead oxide and lead borate. Examples of the metal oxide component include TiO ₂ , ZnO, FTO, ITO, and the like. Furthermore, examples of the electrochemically inactive resin component include polyolefin resins and polyimide resins. And it is possible to use these individually or in combination of 2 or more types.
The method for forming the wiring protective material 15 is not particularly limited, and examples thereof include a method in which a target compound or a precursor thereof is formed by a wet method such as a screen printing method or a dispenser coating method. If necessary, a dry method (vapor phase method) such as a sputtering method, a vapor deposition method, or a CVD method may be used.

A porous oxide semiconductor layer 13 is further provided on the transparent conductive film 12 in a portion where the current collector wiring 16 is not provided. The porous oxide semiconductor layer 13 is a porous semiconductor having a dye supported thereon. The material and formation method of the porous oxide semiconductor layer 13 are not particularly limited, and any material can be used as long as it is normally used for forming a porous semiconductor for solar cells. Examples of such a semiconductor, for _example, can be used as the _{TiO 2, SnO 2, WO 3} , ZnO, Nb 2 O 5, In 2 O 3, ZrO 2, Y 2 O 3, Al 2 O 3.
Examples of the method for forming the porous film include, but are not limited to, a film formation from a sol-gel method, electrophoretic electrodeposition of fine particles, a method of applying a paste and sintering, and the like. A sensitizing dye is adsorbed on the particle surface of the porous oxide semiconductor layer 13.

In wet solar cells, in order to improve conversion efficiency, light in the visible region having a longer wavelength region than the ultraviolet region having a wavelength of 400 nm to 900 nm using a dye having a wide absorption wavelength is equal to or more than light in the ultraviolet region. Absorb more.
As such a sensitizing dye, it is possible to apply a metal complex such as ruthenium complex, porphyrin, phthalocyanine or the like containing bipyridine structure or terpyridine structure as a ligand, or organic dye such as eosin, rhodamine, merocyanine, etc. Of these, those having an excitation behavior suitable for the intended use and the semiconductor used may be appropriately selected.
The sensitizing dye is adsorbed and supported on the surface of the fine particle semiconductor of the porous oxide semiconductor layer 13.

On the other hand, the second electrode 20 includes, for example, a second base material 21 and a catalyst layer 22 covering the surface thereof.
As the second base material 21 constituting the second electrode 20, it is not necessary to have a light transmittance in particular, so that a metal plate can be used, and a flexible material similar to the first base material 11 is used. It doesn't matter. As the second substrate 21, a glass plate is generally used, but other than the glass plate, for example, a plastic such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), or the like. A ceramic sheet such as a film sheet, titanium oxide, or alumina can be used. Then, the above-described conductive film 22 is formed on the second base material 21.

The catalyst layer 22 is formed on one surface of the second base material 21 in order to exchange charges with the electrolyte layer. For example, a thin film made of platinum, chemically stable carbon, or the like is preferable.
Regarding the method of forming the catalyst layer 22, for example, a layer of platinum, carbon, or the like, which has been heat-treated after vapor deposition, sputtering, and application of chloroplatinic acid is preferably used, but is particularly limited as long as it functions as a catalyst. Is not to be done.

  An electrolytic solution forming the electrolyte layer 30 is inserted between the first electrode 10 and the second electrode 20. Examples of the material constituting the electrolyte layer 30 include a liquid electrolyte obtained by dissolving iodine / iodide ions, tertiary butyl pyridine, or the like as an electrolyte component in an organic solvent such as ethylene carbonate or methoxyacetonitrile, or the liquid electrolyte. Examples of the gelling agent include gelled electrolytes obtained by adding polyvinylidene fluoride, polyethylene oxide derivatives, amino acid derivatives and the like as gelling agents.

And the wet solar cell 1 comprised as mentioned above WHEREIN: The part of the area | region (alpha) by which the said metal wiring 14 of the said 1st electrode 10 was distribute | arranged protruded to the outer surface side of the said 1st electrode 10, and the said 1st electrode 10 The portion of the region β where the porous oxide semiconductor layer 13 is arranged is close to the second electrode 20 side.
Therefore, even in a wet solar cell configured with a current collector wiring, the porous oxide semiconductor layer 13 of the first electrode 10 and the first electrode 10 can be formed without providing a special structure such as irregularities on the opposite surface sides of both electrodes. The distance between the two electrodes 20 can be reduced to improve power generation efficiency.
Moreover, the second electrode 20 is stacked on the first electrode 10 by using a flexible substrate as the substrate constituting the first electrode 10 by placing the porous oxide semiconductor layer 13 thereon. Thereafter, the substrate constituting the first electrode 10 is formed by pressurizing or depressurizing the inside of the region β of the first electrode 10 where the porous oxide semiconductor layer 13 is disposed in the stacking direction. Can easily follow the shape of the metal wiring and bend the region β of the first electrode 10 where the porous oxide semiconductor layer 13 is disposed toward the second electrode side 20.

FIG. 2 is a schematic sectional view showing another structure of the wet solar cell according to the present invention.
As shown in FIG. 2, when a portion of the first electrode 10 provided with the porous oxide semiconductor layer 13 is pressurized from the outside, the wet solar cell (photoelectric conversion element) 51 according to the present embodiment is the first electrode. It can be set as the structure by which the sheet | seat materials 41 and 42 were distribute | arranged through the sealing resin material 40 on the outer surface of 10 and the 2nd electrode 20. FIG.
2, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

  The sealing resin material 40 must be transparent because it is necessary to pressurize the first electrode 10 that functions as a window electrode. As the sealing resin material 40, for example, an adhesive, a gel, a liquid, and the like can be considered. In other cases, use a package that can be pressurized during use.

The sheet materials 41 and 42 are a pair of flat plate members that sandwich a laminated body formed by laminating the first electrode 10 and the second electrode 20 from the outer surface and pressurize uniformly in the direction of the surfaces facing each other. . Examples of the sheet materials 41 and 42 include flat glass plates.
By providing such a flat sheet material at least on the first electrode side, the outer surface of the first electrode having a protruding portion is made flat so that sunlight is efficiently incident into the cell without reflection. It can also be.

According to such a configuration, the first wet solar cell 1 can be sealed as a whole, and a surface pressure is applied to the outer surface of the first electrode 10 by the sealing resin material 40, so that the first electrode The portion of the region β where the 10 porous oxide semiconductor layers 13 are arranged is pushed from the outside by the sealing resin material 40 and bent toward the second electrode 20 side, and the metal wiring 14 of the first electrode 10 is arranged. The region α thus formed is not pushed in by the sealing resin material 40 and has a structure protruding to the outer surface side of the first electrode 10.
Therefore, it is easy to produce the deflection of the first electrode 10 toward the two electrodes 20 side, the distance between the electrodes can be reduced, and the photoelectric conversion efficiency can be improved.

Next, an example of a method for manufacturing the wet solar cell 1 according to the present invention will be described.
FIG. 3 to FIG. 5 are diagrams sequentially showing steps for producing the first electrode 10 that functions as a window electrode in a wet solar cell, and FIG. 6 produces the second electrode 20 that functions as a counter electrode in the wet solar cell. It is a figure which shows a process. 7 to 10 are schematic cross-sectional views sequentially showing the steps of manufacturing the wet solar cell 1 according to the present invention by laminating and joining the first electrode 10 and the second electrode 20. .

First, a method for producing the first electrode 10 will be described.
As shown in FIG. 3, a first base material 11 is prepared, and a transparent conductive film 12 is provided on one surface of the first base material 11.
The first substrate 11 may be a flexible glass plate having a plate thickness of 1.5 mm or less, but an economical and lightweight module can be obtained, and a flexible plastic is used. It is desirable to use it. When a plastic substrate is used as the window-side electrode, a firing process for forming a porous oxide semiconductor layer 13 described later, a firing process for forming a metal wiring 14, and a firing process for forming a wiring protective material 15, respectively. Must be carried out at 150 ° C. or lower, so use low-temperature firing materials.
Moreover, as a formation method of the transparent conductive film 12, what is necessary is just to perform using a well-known method according to the material of the transparent conductive film 12, for example, by sputtering method, CVD method (vapor phase growth method), a vapor deposition method, etc. A thin film made of an oxide semiconductor such as fluorine-added tin (FTO) is formed. If this thin film is too thick, the light transmittance is inferior. On the other hand, if it is too thin, the conductivity is inferior. Therefore, considering both the light transmittance and the conductivity, a film thickness of about 0.01 μm to 1 μm is preferable. .
Subsequently, after forming a resist on the formed thin film by a screen printing method or the like, the resist is etched to form a transparent conductive film 12 having a predetermined pattern on the surface of the first base material 11. Thereby, the electroconductive board | substrate for window side electrodes is comprised.

Next, as shown in FIG. 4, current collection wiring 16 is arranged on the transparent conductive film 12 in the conductive substrate for the window side electrode. As a method for forming the current collector wiring 16, for example, a sintered silver paste is applied onto the transparent conductive film 12 by a screen printing method or the like and fired to form the metal wiring. For example, the metal wiring 14 may be formed in a stripe shape with an aperture ratio of 90% and a thickness of about 0.1 μm to 20 μm.
And the current collection wiring 16 is comprised by covering this metal wiring 14 with the wiring protective material 15 which consists of low melting glass, for example.

Next, as shown in FIG. 5, the porous oxide semiconductor layer 13 is formed on the portion of the window-side electrode conductive substrate where the current collector wiring 16 on the transparent conductive film 12 is not disposed. As a method for forming the porous oxide semiconductor layer 13, for example, a titanium dioxide (TiO ₂ ) powder is mixed with a dispersion medium to prepare a paste, which is subjected to a screen printing method, an ink jet printing method, a roll coating method, a doctor blade, or the like. It is applied onto the transparent conductive film 12 by a method such as a spin coating method and baked.
And the 1st electrode 10 is comprised by making a sensitizing dye carry | support between the particle | grains of the porous oxide semiconductor layer 13. FIG. The loading of the sensitizing dye can be achieved, for example, by immersing the conductive substrate on which the porous oxide semiconductor layer 13 is formed in the dye solution.

Next, a method for producing the second electrode 20 will be described.
First, a second substrate 21 made of conductive glass is prepared, and a catalyst film 22 is provided on one surface of the second substrate 21. Platinum or carbon can be used as the catalyst film 22, and the catalyst film 22 can be formed by a known method according to the material of the catalyst film, as in the case of the first substrate 11. For example, it can be formed by a vacuum film forming method such as a sputtering method or a vapor deposition method, or by a wet film forming method in which a platinum-containing solution such as a chloroplatinic acid solution is applied to the surface of the substrate, followed by heat treatment. If the catalyst film 22 is too thin, the catalyst characteristics will be inferior. Therefore, in consideration of the catalyst characteristics, a film thickness of about 0.001 μm to 0.1 μm is preferable.
Subsequently, after a resist is formed on the formed conductive film 22 by a screen printing method or the like, the resist is etched to form a unit cell pattern having a desired shape. Thereby, the electroconductive board | substrate for 2nd electrodes is comprised.

  Next, as shown in FIG. 7, a porous substrate in which the conductive substrate for the first electrode 10 shown in FIG. 5 and the conductive substrate for the second electrode 20 shown in FIG. The oxide semiconductor layer 13 and the conductive film 22 provided on the second electrode 20 are disposed so as to face each other, and the second electrode 20 is stacked on the first electrode 10 to form a stacked body 1a that constitutes a cell.

  Then, as shown in FIG. 8, the portion of the region β in which the porous oxide semiconductor layer 13 is disposed on the conductive substrate for the first electrode 10 is pressurized from the outside in the stacking direction, so that this portion is Bending toward the second electrode 20 side.

  Next, as shown in FIG. 9, an electrolytic solution injection hole 23 reaching the cell portion with a drill or the like is provided from the back surface of the conductive substrate for the second electrode 20, and the first electrode 10 is formed from the electrolytic solution injection hole 23. An electrolyte 30 is injected between the first electrode 20 and the second electrode 20.

  Thereafter, as shown in FIG. 10, the electrolyte solution injection hole 23 is sealed with a sealant 24 made of, for example, a UV curable adhesive, to obtain a wet solar cell 1 as shown in FIG. 1.

With the configuration as described above, the current collecting wiring can reduce the distance between the electrode between the window electrode and the counter electrode with a simple structure without requiring a troublesome work such as providing a special structure such as unevenness on the opposite surface side of both electrodes. A wet solar cell having the required configuration can be manufactured.
Therefore, even if current collection wiring is required, a wet solar cell with improved photoelectric conversion efficiency can be obtained by reducing the distance between the electrodes.

  In the present invention, a flexible substrate is used for the window-side electrode (first electrode), and the portion of the region β where the porous oxide semiconductor layer is arranged is arranged in the direction in which the second electrode is stacked on the first electrode. In addition to physically pressurizing from the outside to reduce the distance between the electrode between the window electrode and the counter electrode, a flexible substrate is used for the window side electrode (first electrode), and between the first electrode and the second electrode After injecting the electrolytic solution into the space, the inside of the space is decompressed by sucking out a part of the injected electrolytic solution using a vacuum pump or the like, and in the region β where the porous oxide semiconductor layer of the first electrode is disposed. The portion can be pressurized by atmospheric pressure in the direction in which the second electrode is laminated on the first electrode, and the distance between the window electrode and the counter electrode can be reduced. Furthermore, in the present invention, when the electrolytic solution is injected between the first electrode and the second electrode and the subsequent temperature change of the electrolytic solution, a pressure change is caused between the first electrode and the second electrode, The distance between the electrode between the window electrode and the counter electrode may be reduced.

(Example)
EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example.
First, as a transparent substrate for a first electrode (hereinafter referred to as a window side substrate), a conductive PET film (trade name) in which a transparent conductive film is provided on one surface of a polyethylene terephthalate (PET) film (first base material). OTEC, manufactured by Oji Tobi Co., Ltd., conductive 10Ω / □, size: 100 mm square, thickness: 0.1 mm) are prepared.
Next, a low-temperature firing type silver paste (trade name; FA353, manufactured by Fujikura Kasei Co., Ltd.) is applied to the formed transparent conductive film 12 by screen printing to a thickness of 10 μm, and sintered at 150 ° C. Metal wiring was formed.
Subsequently, a pre-cut wiring protection sheet (trade name: Himiran sheet HM-52, manufactured by Tamapoly Co., Ltd.) is bonded to the metal wiring by a heat laminating method at 150 ° C. and covered with a wiring protective material. Wiring was formed.

Next, on the formed transparent conductive film, at a position excluding the metal wiring, a low-temperature baking type titanium oxide paste (trade name: PECC01, manufactured by Pexel Technologies) is screen-printed to a thickness of 5 μm. And a porous oxide semiconductor layer made of an oxide titania film was formed by sintering at 150 ° C.
The window-side substrate on which the porous oxide semiconductor layer was formed was immersed in a dye solution, and the dye was supported on the surface of the titania porous film to form a first electrode.

On the other hand, an FTO transparent conductive glass plate (size: 100 mm square, thickness: 1 mm) is prepared as a transparent substrate for the second electrode (hereinafter referred to as a counter electrode substrate).
Next, a conductive film made of platinum was formed on one surface of the counter electrode substrate by a sputtering method to form a second electrode.

And it arrange | positioned so that the porous oxide semiconductor layer provided in said 1st electrode and the electrically conductive film provided in said 2nd electrode might face each other, and it laminated | stacked directly and pressurized from the upper and lower sides, and produced the laminated body.
Furthermore, after taking out each lead wire (not shown) from both poles, sandwich the laminate with a hot melt adhesive sheet that is one size larger from above, further sandwich between glass substrates, perform a vacuum hot press, cool, By depressurizing, pressure-deformation of the laminated and window-side substrate of the laminated body by the hot melt adhesive sheet as a sealing adhesive was performed.

After that, an electrolyte injection hole that reaches the cell part with a drill is formed from the back surface (counter electrode substrate) of the laminate, and the electrolyte is injected into the space between the first electrode and the second electrode from the electrolyte injection hole At the same time, the electrolyte injection hole was sealed with a sealant made of a UV curable adhesive, and a wet solar cell according to an example of the present invention was fabricated.
As the electrolytic solution, an ionic liquid (1-ethyl-3-methylimidazolium-bis (trifluoromethylsulfonyl) imide) containing an iodine / iodide ion redox pair was used.

(Comparative example)
Further, as a comparative example, as a transparent substrate for the first electrode (hereinafter referred to as a window side substrate), 2Ω / □ is provided on one surface of a high strain point glass plate (size: 140 mm square, thickness: 2.8 mm). A transparent conductive film consisting of two layers of FTO / ITO, formed by spray pyrolysis (SPD), and screen-printed with a low-temperature firing type silver paste (trade name; FA353, Fujikura Kasei) Co., Ltd.) was applied in stripes with a thickness of 8 μm and sintered at 150 ° C. to form metal wiring.
Next, a pre-cut wiring protection sheet (trade name; Himiran sheet HM-52, manufactured by Tamapoly Co., Ltd.) is bonded onto the metal wiring by a heat laminating method at 150 ° C. and covered with a wiring protective material. Wiring was formed.

Next, on the formed transparent conductive film, at a position excluding the metal wiring, a low-temperature baking type titanium oxide paste (trade name: PECC01, manufactured by Pexel Technologies) is screen-printed to a thickness of 5 μm. And a porous oxide semiconductor layer made of an oxide titania film was formed by sintering at 150 ° C.
The window-side substrate on which the porous oxide semiconductor layer was formed was immersed in a dye solution, and the dye was supported on the surface of the titania porous film to form a first electrode.

On the other hand, a Ti plate (size: 130 mm square, thickness: 2.0 mm) is prepared as a substrate for the second electrode (hereinafter referred to as a counter electrode substrate).
Next, a conductive film made of platinum having a thickness of 0.1 μm was formed on one surface of the counter electrode substrate by a sputtering method to form a second electrode.

Then, the porous oxide semiconductor layer provided on the first electrode and the conductive film provided on the second electrode are arranged so as to face each other, directly overlap, and the electrolyte is sandwiched in the space between the two and added from above and below. To produce a wet solar cell according to a comparative example.
As the electrolytic solution, an ionic liquid (1-ethyl-3-methylimidazolium-bis (trifluoromethylsulfonyl) imide) containing an iodine / iodide ion redox pair was used.

  And the distance between electrodes and the short circuit current in the wet solar cell of the Example produced as mentioned above and the wet solar cell of a comparative example were measured. The measured values are shown in Table 1.

As a result, as can be seen from Table 1, in the wet solar cell in the example of the present invention, the distance between the electrode between the window electrode and the counter electrode is remarkably smaller than in the wet solar cell in the comparative example, and both the electrodes are in contact with each other. became. Further, since the distance between the electrodes was remarkably reduced, the short-circuit current of the wet solar cell in the example of the present invention was able to obtain a current value twice as high as that of the wet solar cell in the comparative example.
Therefore, in the present invention, even in a wet solar cell having a configuration requiring current collecting wiring, the distance between the electrodes can be reduced without providing a special structure such as unevenness on the opposite surface side of both electrodes, and energy conversion efficiency can be reduced. Can be improved and improved.

  According to the present invention, since the distance between the electrodes can be reduced as much as possible even when the size is increased, a wet solar cell with improved light conversion efficiency can be provided at a low price.

It is a schematic sectional drawing which shows an example of the structure of the wet solar cell which concerns on this invention. It is a schematic sectional drawing which shows another example of the structure of the wet solar cell which concerns on this invention. It is sectional drawing which shows the 1st process which produces the 1st electrode of the wet solar cell of FIG. It is sectional drawing which shows the next process (2nd process) of FIG. It is sectional drawing which shows the next process (3rd process) of FIG. It is sectional drawing which shows the 1st process which produces the 2nd electrode of the wet solar cell of FIG. It is sectional drawing which shows the 1st process of producing the wet solar cell of FIG. It is sectional drawing which shows the next process (2nd process) of FIG. It is sectional drawing which shows the next process (3rd process) of FIG. It is sectional drawing which shows the next process (4th process) of FIG. It is a schematic sectional drawing which shows an example of the structure of the conventional wet solar cell.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,51 Wet solar cell, 1a laminated body, 10 1st electrode, 11 1st base material, 12 transparent conductive film, 13 porous oxide semiconductor layer, 14 metal wiring, 15 wiring protective film, 16 current collection wiring, 20 2nd electrode, 21 2nd base material, 22 catalyst film, 23 electrolyte solution injection hole, 24 sealing material, 30 electrolyte layer, 40 sealing resin material, 41, 42 sheet material.

Claims (5)

A first electrode configured to have a porous oxide semiconductor layer carrying a sensitizing dye and functioning as a window electrode; a second electrode disposed opposite to the first electrode; and the first electrode In a wet solar cell comprising an electrolyte layer disposed at least in part between the second electrode,
The porous oxide semiconductor layer, Oite on a first substrate constituting the first electrode, so that a gap is provided between the metal wires, or are formed so as not provided clearance and, the first electrode, distribution area of the metal wiring α is, the porous oxide semiconductor layer as compared to the region β distribution, that protrudes on the outer surface side of the first electrode A wet solar cell characterized. A first electrode configured to have a porous oxide semiconductor layer carrying a sensitizing dye and functioning as a window electrode; a second electrode disposed opposite to the first electrode; and the first electrode In a wet solar cell comprising an electrolyte layer disposed at least in part between the second electrode,
The porous oxide semiconductor layer is provided at a position excluding the metal wiring formed on the first substrate constituting the first electrode, and the first electrode is a region where the metal wiring is arranged. The wet solar cell is characterized in that α protrudes to the outer surface side of the first electrode as compared with the region β in which the porous oxide semiconductor layer is disposed. The substrate constituting the porous oxide placing the semiconductor layer to the first electrode, the wet solar cell according to claim 1 or 2, characterized in that it is flexible. The wet solar cell according to any one of claims 1 to 3, wherein a sheet material is disposed on an outer surface of the first electrode and the second electrode via a sealing resin material. A first electrode configured to have a porous oxide semiconductor layer carrying a sensitizing dye and functioning as a window electrode; a second electrode disposed opposite to the first electrode; and the first electrode And an electrolyte layer disposed at least in part between the second electrode, and the porous oxide semiconductor layer is provided at a position excluding the metal wiring formed on the first electrode, The electrode is a method for manufacturing a wet solar cell in which the region α in which the metal wiring is disposed protrudes to the outer surface side of the first electrode compared to the region β in which the porous oxide semiconductor layer is disposed. And
A method of manufacturing a wet solar cell, comprising: laminating the second electrode on the first electrode; and then bending the first electrode in the laminating direction by applying pressure from the outside or depressurizing the inside.

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