JP2007287484A - Dye-sensitized solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dye-sensitized solar cell in which an electrolytic solution can be arranged uniformly between both electrode faces without depending on viscosity, and in which damage of a connection part and deterioration of a dye due to heat in sealing can be suppressed. <P>SOLUTION: The dye-sensitized solar cell 10 has a porous oxide semiconductor layer 3 on which the sensitized dye is carried. Moreover, this is provided with a first electrode 2 which functions as a window electrode, and a second electrode 5 which is arranged opposed to the first electrode by interposing an electrolyte layer 6 at least at one part. Furthermore, a first base material 1 at which the first electrode is installed and a second base material 4 at which the second electrode is installed are provided with at least a first region α pinching the electrolyte layer, and a second region β having a recessed part 7 in outer faces of the first base material and/or the second base material, and the second region is arranged so as to surround the first region. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is abbreviated as a dye-sensitized solar cell [hereinafter referred to as “DSC” (Dye-Sensitized Solar Cell). In more detail, an electrolyte solution (electrolyte) is previously provided between the counter electrode substrate and the working electrode substrate without providing a small hole for injecting the electrolyte solution on the counter electrode substrate or the working electrode substrate. The present invention relates to a dye-sensitized solar cell filled and bonded.

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.
In addition, compound solar cells such as Cu—In—Se (also referred to as “CIS”) have been developed and have excellent characteristics such as extremely high photoelectric conversion efficiency. There is a problem such as load, and it is still in a situation where it has obstacles to widespread use.

On the other hand, a dye-sensitized solar cell is proposed by a group of Gretzel et al. In Switzerland, and has attracted attention as a photoelectric conversion element that can obtain high photoelectric conversion efficiency at low cost (for example, Patent Document 1). , See Non-Patent Document 1).
FIG. 10 is a cross-sectional view showing an example of a conventional dye-sensitized solar cell.
The dye-sensitized solar cell 100 includes a first substrate 101 on which a porous semiconductor layer 103 supporting a sensitizing dye is formed on one surface, a second substrate 104 on which a transparent conductive layer 105 is formed, The main component is an electrolyte layer made of a liquid or gel electrolyte enclosed between them.

At this time, for example, a light-transmitting plate material is used as the first substrate 101, and the transparent conductive layer 102 is disposed on the surface of the first substrate 101 in contact with the dye-sensitized semiconductor layer 103 to provide conductivity. The working electrode 108 is formed by the first substrate 101, the transparent conductive layer 102, and the porous semiconductor layer 103.
As the second substrate 104, for example, a conductive layer (not shown) made of carbon, platinum, or the like is provided on the surface in contact with the electrolyte layer 106, that is, on the transparent conductive layer 105 to further ensure electrochemical activity. The counter electrode 109 is configured by the second substrate 104, the transparent conductive layer 105, and the conductive layer (not shown).

The porous substrate layer 103 and the conductive layer (not shown) provided on the transparent conductive layer 105 are opposed to each other, and the first substrate 101 and the second substrate 104 are arranged so as to form a predetermined interval, and between the two substrates. A sealant 107 made of a thermoplastic resin is provided on the periphery of the substrate.
Then, the two substrates 101 and 104 are bonded to each other through the sealant 107, and the cells are stacked. Through the electrolyte injection port 110, oxidation / reduction of I ⁻ / I ₃ ⁻ or the like between the electrodes 108 and 109 is performed. An organic electrolyte solution containing a reducing pair is filled and an electrolyte 106 for charge transfer is formed.

  In this dye-sensitized solar cell, the counter electrode and the working electrode are bonded to each other because the dye is weak against heat. Hereinafter, a method of filling the electrolytic solution from the injection hole is performed. Moreover, the sealing procedure in such a dye-sensitized solar cell is generally performed as follows.

  (1) Working electrode (for example, a transparent conductive film such as fluorine-doped tin oxide is formed on a substrate such as glass, a metal wiring for current collection is formed thereon, and further, titanium oxide or the like is formed thereon. A metal oxide semiconductor is formed and a sensitizing dye is supported on the metal oxide semiconductor) and a counter electrode (for example, a metal thin film such as platinum is formed on a substrate such as glass). Prepare in advance and use an adhesive film (for example, “Surlin” or “Binell” manufactured by DuPont, or “High Milan” manufactured by Mitsui DuPont Polychemical Co., Ltd.) to attach both electrodes using a heating press at about 80 to 150 ° C. . Thereafter, an electrolytic solution is introduced into the inside of the electrolytic solution injection hole previously opened in the working electrode, the counter electrode, and the adhesive film, and the injection hole is sealed with an adhesive (see, for example, Patent Document 2).

  (2) As in (1) above, a working electrode and a counter electrode are prepared in advance, and both electrodes are bonded together using a photo-curing resin (for example, “3003” manufactured by ThreeBond). Thereafter, an electrolytic solution is introduced into the inside from an electrolytic solution injection hole previously opened in a working electrode, a counter electrode, an adhesive film, etc., and the injection hole is sealed with an adhesive (for example, see Patent Document 3).

  (3) Working electrode (for example, a transparent conductive film such as fluorine-doped tin oxide is formed on a substrate such as glass, a metal wiring for current collection is formed thereon, and further, a titanium oxide or the like is formed thereon. A metal oxide semiconductor is formed and a counter electrode (for example, a metal thin film such as platinum is formed on a substrate such as glass) is prepared in advance, and both electrodes are made of a low-temperature glass frit (for example, PbO). ), And heat-sealed in an oven at about 400 to 600 ° C. Thereafter, a sensitizing dye is supported on the metal oxide semiconductor by circulating a dye solution through an electrolyte solution injection hole previously opened in a working electrode, a counter electrode, an adhesive film, etc., and then an electrolyte solution (or ion) Liquid) and the injection hole is sealed with an adhesive (for example, see Patent Document 4).

  (4) As in (1) above, a working electrode and a counter electrode are prepared in advance, and an electrolyte using a high viscosity solvent such as an ionic liquid, a solid such as a nanocomposite ion gel electrolyte, a quasi-solid electrolyte, and conventional electrolysis A liquid or the like is sandwiched between the two electrodes and sealed in a separately prepared airtight package (see, for example, Patent Document 5).

  (5) Similar to (1) above, a working electrode and a counter electrode are prepared in advance, and an electrolyte using a high viscosity solvent such as an ionic liquid, a solid such as a nanocomposite ion gel electrolyte, a quasi-solid electrolyte, and conventional electrolysis Cover the area with a photo-curing resin with the liquid sandwiched between the electrodes and hold the electrodes, and then expose and seal.

  However, in each of the production methods (1), (2), and (3), the electrolyte is injected through a thin path such as an electrode gap or an injection hole, so that a highly viscous electrolyte takes a very long time. However, there is a limitation that only an electrolyte solution having a low viscosity can be used. Further, since heat is applied to the entire surface, stress is generated in the substrate, so that the joint portion is easily damaged and there is a possibility that the shielding from the outside air is insufficient.

  In addition, the production method (4) above can be applied to solid and high-viscosity electrolytes, but there is a drawback that the cell and the sealed package are prepared separately. Otherwise, liquid leakage and liquid movement will occur inside the package.

In addition, in the production method of (5), as in the case of (4), it can be applied to a solid or high-viscosity electrolyte, but it is difficult to clean the surrounding adhesive part without affecting the cell. It is necessary to seal the surface to be bonded in a dirty state. In general, when the surface to be bonded is not clean, the adhesive strength is reduced, so that the sealing reliability is lowered.
As described above, methods for sealing solar cells using a high-viscosity electrolytic solution, a pseudo solid, or a solid electrolyte are limited, and each of these methods has a problem of impairing the reliability of sealing.

  Furthermore, a working electrode (for example, a transparent conductive film such as fluorine-doped tin oxide is formed on a substrate such as glass, a metal wiring for current collection is formed thereon, and a metal such as titanium oxide is further formed thereon. An oxide semiconductor is formed and a sensitizing dye is supported on the metal oxide semiconductor) and a counter electrode (for example, a metal thin film such as platinum is formed on a substrate such as glass) in advance. After preparing and arranging a glass frit layer on the peripheral edge of the substrate, these two electrodes are overlapped. And both electrodes are bonded together by irradiating a laser beam through one substrate. Thereafter, it has also been proposed that an electrolytic solution (or ionic liquid) is put inside from an electrolytic solution injection hole previously opened in a working electrode, a counter electrode, an adhesive film, and the injection hole is sealed with an adhesive ( For example, see Patent Document 6).

However, in this case as well, since the electrolyte solution is filled from the injection hole, only an electrolyte solution having a low viscosity can be used, and injection is difficult when the viscosity is high like a gel electrolyte solution. Even if it is injected, since the electrolyte spreads only in a small area, there is a limitation that it cannot cope with the increase in the area of the solar cell.
Japanese Patent No. 2664194 JP 2001-35549 A JP 2000-1000048 A JP 2000-348783 A JP 2005-71973 A JP 2004-172048 A O 'Regan B, Gratzel M. A low cost, high-efficiency solar cell based on dye-sensitized colloidal TiO2 films, Nature 1991; 353: 737-739

  The present invention has been made in view of the above circumstances, and it is possible to uniformly dispose the electrolytic solution in the plane between both electrodes without depending on the viscosity, and damage of the connection portion due to heat at the time of sealing or coloring matter. It aims at providing the dye-sensitized solar cell which can also suppress degradation.

  A dye-sensitized solar cell according to claim 1 of the present invention includes a porous oxide semiconductor layer carrying a sensitizing dye, a first electrode functioning as a window electrode, and at least a part of an electrolyte. A dye-sensitized solar cell comprising a second electrode disposed opposite to the first electrode via a layer, wherein the first substrate on which the first electrode is provided and the second electrode on which the second electrode is provided The two substrates include at least a first region sandwiching the electrolyte layer and a second region having a recess on an outer surface of the first substrate and / or the second substrate in the overlapping direction, The region is arranged to surround the first region.

  The dye-sensitized solar cell according to claim 2 of the present invention is the dye-sensitized solar cell according to claim 1, and includes a third region having a gap between the substrates so as to surround the second region. It is characterized by that.

  The dye-sensitized solar cell according to claim 3 of the present invention is the dye-sensitized solar cell according to claim 1 or 2, wherein the members constituting the first base material and the second base material are ultrasonic waves. It consists of the material which lets it pass.

  The dye-sensitized solar cell according to claim 4 of the present invention is characterized in that in the dye-sensitized solar cell according to claim 1 or 2, the bonding interface of the second region is welded.

  The dye-sensitized solar cell according to claim 5 of the present invention is the dye-sensitized solar cell according to claim 1, wherein the main absorption of Ru dye is 550 nm through the first base material or the second electrode. The variation in reflectance obtained when observing with light is within 50% within one cell.

The present invention includes a first base material provided with a first electrode functioning as a window electrode, and a second base material provided with a second electrode disposed at least partially facing the first electrode via an electrolyte layer. In the overlapping direction, the first substrate and / or the second substrate has a second region having a recess on the outer surface so as to surround the first region sandwiching the electrolyte layer. Therefore, by constructing the second region having the recess by applying an ultrasonic wave so as to surround the first region, only the portion to which the ultrasonic wave is applied is locally heated and heated without heating the entire substrate. By melting and joining the first base material and the second base material to form a sealing portion, sealing is performed in which the electrolyte layer is surely shielded from outside air. In addition, the electrolyte solution temporarily escapes from the melted portion by local heating and vibration due to the application of ultrasonic waves, and the electrolyte layer is surely sealed even when the joint is wet with the electrolyte solution. be able to.
Therefore, it is possible to provide a dye-sensitized solar cell that can uniformly dispose the electrolyte solution in the plane between both electrodes without depending on the viscosity, and can suppress damage to the connecting portion and deterioration of the dye due to heat during sealing. can do. That is, according to the present invention, the dye-sensitized solar cell is not limited to the low-viscosity type, and a high-viscosity gel electrolyte can be used and can easily cope with an increase in the area of the solar cell. Is obtained. In addition, the first substrate or the second substrate can be a dye-sensitized solar cell having a simple structure without a small hole for injecting an electrolyte.

Hereinafter, an embodiment of a dye-sensitized solar cell according to the present invention will be described with reference to the drawings.
FIG. 1 is a view showing the structure of a dye-sensitized solar cell according to the present invention, FIG. 1 (a) is a schematic plan view thereof, and FIG. 1 (b) is an A view shown in FIG. 1 (a). It is a schematic sectional drawing which follows the -A line.
As shown in FIG. 1, a dye-sensitized solar cell 10 according to this embodiment includes a first substrate 1 and a transparent conductive film 2 that functions as a first electrode and is disposed on one surface of the first substrate 1. And the porous oxide semiconductor layer 3 provided on the transparent conductive film 2 is a window electrode substrate 8 on the light incident side. On the other hand, a structure composed of the second base material 4 and the metal thin film 5 functioning as the second electrode disposed on one surface of the second base material 4 is referred to as a counter electrode substrate 9. Then, an electrolyte solution (or electrolyte gel) 6 is sandwiched between the window electrode substrate 8 and the counter electrode substrate 9, and a recess is formed on the outer surface of at least one of the base materials 1 and 4 (first base material 1 in the illustrated example). 7 is formed so as to surround the electrolytic solution 6.

Moreover, the 1st base material 1 which provides the transparent conductive film 2, and the 2nd base material 4 which provides the metal thin film 5 are the 2nd area | region (alpha) which sandwiches the said electrolyte layer 6, and the said recessed part 7 in the overlapping direction. And the second region β is disposed so as to surround the first region α.
As described above, when the second region β including the concave portion 7 that forms the sealing portion 11 is disposed so as to surround the first region α, there is no deterioration of the dye when the two electrode layers are joined. The electrolyte layer 6 disposed in the first region α can be blocked from the outside air.

The first base material 1 is not particularly limited as long as it is a transparent member that has a conductivity to conduct electricity by forming a film (layer) made of a conductive material on the surface and has a high light transmittance. As the first substrate 1, a glass plate is generally used, but other than the glass plate, for example, plastics such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polycarbonate (PC). Further, a ceramic polishing plate such as titanium oxide or alumina can be used.
In addition, the first base material 1 is conductive to withstand a high heat of about 500 ° C. when titanium dioxide (TiO ₂ ) is formed by baking as a porous semiconductor for dye support on a substrate on which a conductive film is formed later. Heat resistant glass is desirable.

The transparent conductive film 2 is a conductive film made of a conductive material formed on the first base material 1. As the transparent conductive film 2, for example, a transparent oxide semiconductor such as tin-added indium oxide (ITO), tin oxide (SnO ₂ ), or fluorine-added tin (FTO) is used alone or in combination of a plurality of types. Anyway. The transparent conductive film 2 has a high light transmittance when formed on the first substrate 1.
Thus, the electrode substrate is formed by forming the transparent transparent conductive film 2 having a high light transmittance on the first base material 1.

The porous oxide semiconductor layer 3 is a porous semiconductor having a dye supported thereon. There are no particular limitations on the material and formation method of the porous oxide semiconductor layer 3. For example, titanium dioxide (TiO ₂ ), tin oxide (SnO ₂ ), tungsten oxide (WO ₃ ), zinc oxide (ZnO) ), Niobium oxide (Nb ₂ O ₅ ) or the like, or a composite of two or more, and is a porous thin film mainly composed of oxide semiconductor particles having an average particle diameter of 5 nm to 50 nm, and commercially available fine particles Or a colloidal solution obtained by a sol-gel method.
As a method for forming a porous film, for example, colloidal solutions and dispersions (including additives as necessary), various coating methods such as screen printing, inkjet printing, roll coating, doctor blade, spin coating, spray coating, etc. In addition to coating by coating, electrophoretic electrodeposition of fine particles, combined use of a foaming agent, etc. may be used. A sensitizing dye is contained between the particles of the porous oxide semiconductor layer 3.

  As the sensitizing dye, for example, a ruthenium complex containing a bipyridine structure or a terpyridine structure as a ligand, a metal-containing complex such as porphyrin or phthalocyanine, and an organic dye such as erosine, rhodamine or merocyanine may be used. In accordance with the use and the material of the semiconductor oxide porous layer to be used, an appropriate one can be appropriately selected without particular limitation.

  On the other hand, the second substrate 4 is not particularly limited as long as it is formed by forming a film (layer) made of a conductive material on the surface or is a member that conducts electricity alone. As the second base material 4, 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. Polishing of ceramics such as a film sheet, titanium oxide, and alumina, and metals such as Ti can be used. Then, a metal thin film 5 described later is formed on the second substrate 4.

  The metal thin film 5 can be made of, for example, platinum or chemically stable carbon. Regarding the method of forming the metal thin film 5, for example, when the metal thin film 5 is made of platinum, a vacuum film forming method such as a sputtering method or a vapor deposition method, or a wet method in which a heat treatment is applied after applying a platinum-containing solution such as a chloroplatinic acid solution to the substrate surface It can be performed using a film forming method or the like.

As the electrolytic solution 6, for example, an organic solvent containing a redox pair, an ionic liquid (room temperature molten salt), or the like can be used.
The oxidation-reduction pair is not particularly limited. For example, iodine / iodide ion, bromine / bromide ion, etc. can be selected. In the former case, iodide salt (lithium salt, quaternized imidazolium salt, tetra Butylammonium salt and the like can be used alone or in combination, and iodine can be added alone or in combination.

Examples of the organic solvent include volatile electrolytes using acetonitrile, methoxyacetonitrile, propionitrile, ethylene carbonate, propylene carbonate, diethyl carbonate, γ-butyrolactone, and the like.
Examples of the ionic liquid include, for example, a room temperature meltable salt that is a quaternary imidazolium derivative, a quaternized pyridinium derivative, a quaternized ammonium atom-containing compound having a quaternized nitrogen atom as a cation at room temperature. There is.

A so-called gel electrolyte obtained by suppressing the fluidity of such an electrolytic solution 6 by introducing an appropriate gelling agent and filler and so-called gel electrolyte may be used.
Various additives such as lithium salt and tert-butylpyridine may be further added to the electrolytic solution 6 as necessary. Further, a polymer solid electrolyte having a charge transporting ability as in the case of such an electrolytic solution may be used.

  The concave portion 7 is a groove formed by, for example, pressing the tip of an ultrasonic oscillator that generates ultrasonic waves on the outer surface of the substrate 1 (4), or scanning while pressing and applying ultrasonic waves. is there. In this way, since the two electrode substrates 8 and 9 can be sealed by simply scanning the place to be sealed with an ultrasonic oscillator, it is simpler and faster than other methods such as a hot press method. In addition, the influence of the heat deterioration of the heat generating portion can be reduced. Moreover, since the electrolyte solution 6 can be sandwiched sufficiently and uniformly regardless of the viscosity, the energy conversion efficiency can be improved.

  This ultrasonic sealing can be used for combinations of plastic substrates / plastic substrates, plastic substrates / metal substrates, plastic substrates / glass substrates, and the like. Therefore, when an ultrasonic wave is applied while strongly pressing a portion to be sealed, the portion is locally heated and melted and can be joined.

  Moreover, in the dye-sensitized solar cell 10 according to the present invention, even when the space between the two electrode substrates 8 and 9 is wet with the electrolyte solution 6, the welded portion is locally pressurized, and the ultrasonic wave As a result, a cavity is generated and the electrolytic solution 6 avoids the sealing portion 11, so that the sealing is normally performed without any problem. Therefore, it becomes possible to use also for electrolyte solution with high viscosity.

  According to such a configuration, the sealed portion is firmly bonded, has high chemical, mechanical, and thermal properties, and exhibits excellent durability and safety. Even when the battery 10 is used outdoors under severe conditions for a long time, the electrolytic solution 6 does not leak from the sealed portion, and moisture and foreign matter do not enter.

  Further, since the ultrasonic wave is applied only to the second region disposed so as to surround the first region α sandwiching the electrolytic solution 6, it is supported by the porous oxide semiconductor layer 3 formed on the first substrate 1. The photosensitizing dye is not deteriorated by heating, and the first substrate 1 carrying the dye can be bonded and sealed, and the manufacturing operation is simplified. In addition, since heat is not generated compared to the sealing method using laser light, it is not necessary to place a distance between the porous oxide semiconductor layer 3 and the sealing portion 11.

Moreover, as shown in FIG. 1, you may provide the 3rd area | region (gamma) provided with a space | gap between board | substrates so that the said 2nd area | region (beta) may be enclosed.
As described above, by providing the gap by the third region γ, the sealant can be promoted in the gap, so that it is possible to further block the outside air. Further, since the third region γ also serves as an insulating portion, it also prevents a short circuit of the cell.

  Moreover, it is preferable that the member which comprises said 1st base material 1 and said 2nd base material 4 consists of the material which lets an ultrasonic wave pass. By applying ultrasonic waves through the two base materials 1 and 4, the two base materials 1 and 4 are softened and melted, and the adhesive force is further increased, and the connecting portion is securely connected without using an adhesive layer. It will be fixed to.

  Moreover, it is preferable in the sealing part 11 formed in the joining interface of said 2nd area | region (beta) being what was welded. If the bonding interface between the two substrates 1 and 4 is welded, the connecting portion is securely fixed.

Furthermore, when the dye-sensitized solar cell 10 according to the present invention observes the first region α using light having a main absorption of 550 nm of the Ru dye through the metal thin film 5 as the first substrate 1 or the second electrode. The obtained variation in reflectance is within 50% within one cell.
Thus, since there is little support | carrier nonuniformity of pigment | dye, favorable electric power generation efficiency is obtained.

  In the above description, the example in which the present invention is applied to the working electrode incident type cell structure has been described in detail. However, the present invention is not limited to this structure, and the present invention is not limited to this structure. The present invention is applicable.

Moreover, you may give uneven | corrugated processing to the inner surface of the 1st base material 1 and / or the 2nd base material 4. FIG. This uneven | corrugated process can be performed by using the etching method etc., when a glass plate is used as any one of the base materials 1 (4). Further, when any one of the base materials 1 (4) is a metal, it is possible to perform uneven processing by using a cutting method, a pressing method, a casting method, an etching method, etc., for example, pure titanium is suitable as a material. It is. Furthermore, when any one of the base materials 1 (4) is a plastic, it is possible to perform uneven processing by a simple method such as an injection molding method, a cutting method, or a die stamp method. Moreover, when a plastic is used for any of the base materials 1 (4), a lightweight module can be obtained economically.
As a result, the two electrode substrates 8 and 9 can be easily heated and melted and bonded together by applying ultrasonic waves without strongly pressing a portion to be sealed in the substrate.

In addition, an adhesive layer (not shown) for joining and sealing the bipolar substrates 8 and 9 by heating and melting by applying ultrasonic waves may be provided between the bipolar substrates 8 and 9. As the adhesive layer, for example, a thermoplastic resin typified by high Milan can be used. In addition, the adhesive layer can be arranged in a band shape by applying it to one or both of the electrode substrates 8, 9 by applying means such as printing, heating, drying, or pre-baking.
Thus, when an adhesive layer is disposed between the bipolar substrates 8 and 9, an appropriate adhesive layer can be selected according to the transmittance, the thermal expansion coefficient, the film formability, and the like. Therefore, for example, since it functions also as a buffer layer when using base materials having different linear expansion coefficients, it is possible to increase the degree of freedom in design, such as suppressing deterioration with time of the sealed portion.

Next, an example of a method for producing the dye-sensitized solar cell 10 according to the present invention will be described.
FIG. 2 to FIG. 4 are diagrams sequentially showing steps for producing a window electrode substrate 8 provided with an electrode functioning as a window electrode in a dye-sensitized solar cell. FIGS. 5 and 6 are diagrams in the dye-sensitized solar cell. It is a figure which shows sequentially the process of producing the counter electrode substrate 9 provided with the electrode which functions as a counter electrode. 7 and 8 are schematic cross-sectional views showing an example of manufacturing the dye-sensitized solar cell according to the present invention by bonding the window electrode substrate 8 and the counter electrode substrate 9 together.

First, a method for producing the window electrode substrate 8 will be described.
As shown in FIG. 2, a first substrate 1 is prepared, and a transparent conductive film 2 is provided on one surface of the first substrate 1.
As the first base material 2, a glass plate that is usually used may be used. However, a plastic that can reduce the cost and reduce the weight may be employed.
As a method for forming the transparent conductive film 2, a known method may be used depending on the material of the transparent conductive film 2. For example, a sputtering method, a CVD method (vapor phase growth method), an SPD method (spray heat) is used. A thin film made of an oxide semiconductor such as fluorine-added tin (FTO) is formed by a decomposition deposition method) or an evaporation method. If this thin film is too thick, the light transmittance is inferior, while if it is too thin, the conductivity is inferior. Therefore, in consideration of both the light transmittance and the conductivity, the thin film is formed to a thickness of about 0.2 μm to 2 μm. To do. Thus, a conductive substrate for the window-side electrode is formed. Subsequently, a resist is formed on the formed thin film by a screen printing method or the like, and then the resist is etched on the surface of the first substrate 1. Then, a transparent conductive film 2 having a predetermined pattern is produced. Thereby, the electroconductive board | substrate for window side electrodes is comprised.

Next, as shown in FIGS. 3 and 4, the porous oxide semiconductor layer 3 is formed on the transparent conductive film 2 in the conductive substrate for the window side electrode. As a method for forming the porous oxide semiconductor layer 3, 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 2 by a method such as a spin coating method and baked. And this porous oxide semiconductor layer 3 is formed in about 2 micrometers-30 micrometers.
The window electrode substrate 8 is configured by supporting a sensitizing dye between the particles of the porous oxide semiconductor layer 3. The loading of the sensitizing dye can be achieved, for example, by immersing the conductive substrate on which the porous oxide semiconductor layer 3 is formed in the dye solution.

Next, a manufacturing method of the counter electrode substrate 9 provided with an electrode functioning as a counter electrode will be described.
First, a second substrate 4 made of plastic is prepared, and a conductive layer is provided on one surface of the second substrate 4. As a method for forming the conductive layer, similarly to the case of the first substrate 1, a known method may be used according to the material of the conductive layer. For example, a sputtering method, a CVD method (vapor phase growth method), A thin film made of an oxide semiconductor such as fluorine-added tin (FTO) is formed by SPD (spray pyrolysis deposition) or vapor deposition. If the conductive layer is too thick, the cost increases. On the other hand, if the conductive layer is too thin, the conductivity is inferior. Therefore, considering both the cost and the conductivity, the film is about 0.2 μm to 2 μm. Form thick. Thereby, the electroconductive board | substrate for counter electrodes is comprised.
Subsequently, after a resist is formed on the deposited conductive layer by a screen printing method or the like, the resist is etched to produce a unit cell pattern having a desired shape.
Thereby, the electroconductive board | substrate for counter electrodes is comprised.

Next, as shown in FIG. 5, the metal thin film 5 is formed on the conductive layer in the conductive substrate for the counter electrode. As the metal thin film 5, platinum or carbon can be used, and it can be formed by a vacuum film forming method such as a sputtering method or a vapor deposition method. In addition, a wet process in which a platinum-containing solution such as a chloroplatinic acid solution is applied to the substrate surface and heat treatment is applied. It can also be performed by a film forming method. The thickness of the metal thin film 5 is about 0.005 μm to 0.3 μm.
Subsequently, after a resist is formed on the formed metal thin film 5 by a screen printing method or the like, the counter electrode substrate 9 is configured by etching away unnecessary portions.

  Although not shown in the figure, a heat sealable adhesive is applied onto the second base material 4 on which the metal thin film 5 is formed by an application means such as printing, and is then dried or pre-baked to produce ultrasonic waves. An adhesive layer that is heated and melted may be formed by applying. The adhesive layer may be formed by attaching a resin film.

  Next, as shown in FIG. 7, the porous oxide semiconductor layer 3 in which the window electrode substrate 8 shown in FIGS. 3 and 4 and the counter electrode substrate 9 shown in FIGS. 5 and 6 are provided on the window electrode substrate 8. And the metal thin film 5 provided on the counter electrode substrate 9 are opposed to each other, and as the electrolyte 6, an electrolyte using a high viscosity solvent such as an ionic liquid, a solid or quasi-solid electrolyte such as a nanocomposite ion gel electrolyte And the bipolar substrates 8 and 9 are overlapped so as to sandwich the conventional electrolyte.

Then, as shown in FIG. 8, in a state where the portion to be sealed is strongly pressed, the tip of the ultrasonic oscillator 12 is pressed against the outer surface of one or both of the base materials, or scanned while being pressed. By applying ultrasonic waves so as to surround the electrolytic solution 6, the ultrasonic waves pass through the base material and seal the periphery of the electrolytic solution 6, thereby obtaining a dye-sensitized solar cell 10 as shown in FIG. 1.
As an ultrasonic bonding apparatus provided with this ultrasonic oscillator, for example, as shown in FIG. 9A, a linear type ultrasonic bonding capable of applying ultrasonic waves to a predetermined region at a time. As shown in FIG. 9B, an apparatus 12A and a bowl-shaped (or pen-shaped) type ultrasonic bonding apparatus 12B capable of applying ultrasonic waves locally while scanning can be used. Although not shown, a frame-type ultrasonic bonding apparatus that can apply ultrasonic waves in a ring shape at a time may be used.

  With the above configuration, the electrolyte layer can be uniformly disposed in the plane between both electrodes without depending on the viscosity of the electrolytic solution. Therefore, the bipolar substrate or the like has no small holes for injecting the electrolyte, and can have a simple structure. In addition, the sealing of the electrolyte layer by joining the bipolar substrates partially heats and melts the portion applied by the application of ultrasonic waves, so that the whole substrate is not heated, and the connection portion by the heat at the time of sealing Damage and pigment deterioration can be suppressed, and the electrolyte layer can be reliably shielded from the outside air. In addition, even when the joint portion is wet with the electrolytic solution, the electrolyte layer can be reliably sealed by local heating using ultrasonic waves.

EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example.
First, as a window electrode base material (first base material 1), a polyethylene naphthalate (PEN) film, a polyethylene terephthalate (PET) film, and a 40 μm-thick metal titanium foil each having a size of 15 mm × 20 mm were prepared. After forming a transparent conductive film 2 as shown in Table 1 on one surface of the substrate excluding the titanium foil, a titanium oxide paste was applied thereon to form a porous oxide semiconductor layer 3 made of a titania film. .

  When the window electrode base material is a polyethylene naphthalate (PEN) film or a polyethylene terephthalate (PET) film, the porous oxide semiconductor layer 3 is made of titanium oxide paste (“Ti-nanoxide” on a resin film using a mending tape as a spacer. (T / L ”: manufactured by Solaronix), dried, baked at 150 ° C. for 30 minutes in a hot air circulation oven, and taken out of the oven, so that the electrode area becomes 10 mm × 10 mm. The excess porous titania porous membrane was scraped off.

  Then, each window electrode base material on which the porous oxide semiconductor layer 3 is formed is immersed overnight in a mixed solvent of equal amounts of 0.3 mM N3 dye (“Ruthenium535” manufactured by Solaronix), t-butanol and acetonitrile. A dye was supported on the surface of the titania porous film to form window electrode substrates 8 respectively.

  On the other hand, as a counter electrode base material (second base material 4), a polyethylene naphthalate (PEN) film, a polyethylene terephthalate (PET) film, and a metal titanium foil (40 μm thickness) each having a size of 15 mm × 20 mm were prepared. On the upper surfaces of these base materials, platinum having a sheet resistance of 10 Ω / □ was formed as a metal thin film 5 to a thickness of 30 nm by sputtering, and each was used as a counter electrode substrate 9.

Then, the porous oxide semiconductor layer 3 provided on the window electrode substrate 8 and the metal thin film 5 provided on the counter electrode substrate 9 are arranged so as to face each other, and the electrolyte solution 6 is filled therebetween to sandwich the electrolyte solution 6. Thus, the bipolar substrates 8 and 9 were directly overlapped.
In addition, at this time, apart from the case where the bipolar substrates 8 and 9 are directly overlapped, the periphery of the porous oxide semiconductor layer 3 of the window electrode substrate 8 is surrounded as an adhesive layer on the metal thin film 5 side of the counter electrode substrate 9. An annular resin film having a width of 1 mm is disposed, and the porous oxide semiconductor layer 3 provided on the window electrode substrate 8 and the metal thin film 5 provided on the counter electrode substrate 9 are disposed so as to face each other, and electrolysis is performed therebetween. The liquid 6 was filled, and a substrate in which the bipolar substrates 8 and 9 were overlapped via the adhesive layer (resin film) was also prepared.

This electrolyte solution 6 includes 1.5M 1-ethyl-3-methylimidazolium iodide (abbreviated as “EMIm-I”) in 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (abbreviated as “EMIm-TFSI”) solution. ), 0.1M LiI, 0.15M I ₂ , 0.5M 4-t-buthylpyridene (abbreviation “TBP”), 0.8 wt% H ₂ O dissolved (abbreviation “ionic liquid type”) ), 0.3 M 1,2-dimethyl-3-propylimidazoliumiodide, 0.1 M LiI, 0.05 M I ₂ , 0.5 M TBP dissolved in methoxyacetonitrile solvent (volatile type), and What added 10 wt% titania nanoparticle (25 nm) to the ionic liquid type (abbreviation "ion gel type") was used.

  Then, in a state where the portions to be sealed of the stacked bipolar substrates 8 and 9 are pressed firmly, the tip of the ultrasonic oscillator 12 is pressed and the ultrasonic wave is applied locally while scanning, thereby sealing the periphery. The window electrode substrate 8 and the counter electrode substrate 9 were bonded together to form a cell. For ultrasonic bonding, “SONOPET250B” manufactured by Seidensha Electronics Co., Ltd. was used.

Combinations of the superimposed window electrode substrate 8 and counter electrode substrate 9 and adhesive layer are shown in Table 2.
The adhesive layer is an olefin resin film having a thickness of 50 μm (“High Milan”: Mitsui DuPont Polychemical Co., Ltd.) “A”, a polyethylene terephthalate (PET) film having a thickness of 75 μm is “B”, and there is no adhesive layer. A sample obtained by joining the window electrode substrate 8 and the counter electrode substrate 9 directly (C) is shown in Table 1.

  Further, as Comparative Example 1, a polyethylene terephthalate (PET) film having a size of 15 mm × 20 mm was prepared as a window electrode base material, and fluorine-doped oxidation with a sheet resistance of 10Ω / □ was performed on the upper surface of the base material by the SPD method. A tin (FTO) film was formed to a thickness of 1 μm as a transparent conductive film. Next, a titanium oxide paste [Ti-nanoxide T (manufactured by Solaronix)] is applied on the formed transparent conductive film to a thickness of 10 μm, dried, and then dried at 450 ° C. in a hot air circulation type oven. After firing for 5 minutes and taking out from the oven, a porous titanium oxide film (hereinafter referred to as titania) functioning as a porous oxide semiconductor layer is scraped off so that the electrode area becomes 10 mm × 10 mm. Also called a porous membrane). Then, the glass plate on which the porous titanium oxide film was formed was immersed in a mixed solvent of 0.3 mM N3 dye ("Ruthenium535" manufactured by Solaronix), t-butanol, acetonitrile, and the like overnight to form a titania porous film. A dye was supported on the surface to obtain a window electrode substrate.

On the other hand, a polyethylene terephthalate (PET) film having a size of 15 mm × 20 mm was prepared as a counter electrode substrate, and a 20 nm thick platinum film having a sheet resistance of 10Ω / □ was formed on the upper surface of the substrate by sputtering. Each was formed as a counter electrode substrate.
And both electrode board | substrates were bonded together by the hot press at about 140 degreeC without the contact bonding layer. Thereafter, an electrolytic solution was introduced into the inside from an electrolytic solution injection hole previously opened in a window electrode, a counter electrode, an adhesive film, etc., and the injection hole was sealed with an adhesive to form a cell.

  Furthermore, as Comparative Example 2, a polyethylene terephthalate (PET) film having a size of 15 mm × 20 mm was prepared as a window electrode base material, and fluorine-doped oxidation with a sheet resistance of 10Ω / □ was performed on the upper surface of the base material by the SPD method. A tin (FTO) film was formed to a thickness of 1 μm as a transparent conductive film. Next, a titanium oxide paste [Ti-nanoxide T (manufactured by Solaronix)] is applied on the formed transparent conductive film to a thickness of 10 μm, dried, and then dried at 450 ° C. in a hot air circulation type oven. After firing for 5 minutes and taking out from the oven, a porous titanium oxide film (hereinafter referred to as titania) functioning as a porous oxide semiconductor layer is scraped off so that the electrode area becomes 10 mm × 10 mm. Also called a porous membrane). Then, the glass plate on which the porous titanium oxide film was formed was immersed in a mixed solvent of 0.3 mM N3 dye ("Ruthenium535" manufactured by Solaronix), t-butanol, acetonitrile, and the like overnight to form a titania porous film. A dye was supported on the surface to obtain a window electrode substrate.

On the other hand, a polyethylene terephthalate (PET) film having a size of 15 mm × 20 mm was prepared as a counter electrode substrate, and a 20 nm thick platinum film having a sheet resistance of 10Ω / □ was formed on the upper surface of the substrate by sputtering. Each was formed as a counter electrode substrate.
And after filling electrolyte solution between both electrode board | substrates, both electrode board | substrates were made into the bonding cell with the heating press of about 140 degreeC without the contact bonding layer.

And while confirming the sealing state of the electrolyte solution in Examples 1 thru | or 7 produced as mentioned above and Comparative Examples 1 and 2, light was applied to each whole cell, and the energy conversion efficiency was measured. The power generation characteristics were measured under pseudo sunlight of 100 mW / cm ² and AM-1.5. The results are shown in Table 3. The sealed state was indicated by “◯” when there was no leakage of the electrolytic solution, and “X” when there was leakage of the electrolytic solution.

  In addition, when a substantially central portion of one cell (10 mm square) is divided into 16 squares (= 4 × 4, 1 square = 2 mm square), and each square is observed using light having a main absorption of 550 nm of a Ru dye. The reflectance obtained was measured. Then, by calculating the difference [%] between the maximum value and the minimum value of the reflectance obtained for each cell, the variation in reflectance within one cell (shown as discoloration [%] in Table 3). It was. In the evaluation column of Table 3, when the discoloration is 30% or less (○ mark), when the discoloration is 50% or less (△ mark), and when the discoloration exceeds 50% (× mark), specify by symbol did.

  As a result, in the sealed state of the electrolytic solution, the heated press could not be reliably sealed if the joined portion was wet. However, according to the ultrasonic wave, the joined portion was wet. Even if it was able to seal reliably. Therefore, it can be seen that the dye-sensitized solar cell of the present invention can use electrolytes and electrolytes of all viscosities without damage to the connecting portion due to heat.

  Moreover, in energy conversion efficiency, all showed the energy conversion efficiency which is not inferior compared with the comparative example 1 by a conventional method. Therefore, according to the ultrasonic wave, the energy conversion efficiency can be improved without decreasing.

It is a figure which shows an example of the structure of the dye-sensitized solar cell which concerns on this invention, (a) is a schematic plan view, (b) is a schematic sectional drawing which follows the AA line shown to (a). It is a schematic sectional drawing which shows the 1st process of an example which produces the board | substrate provided with the electrode which functions as a 1st electrode (window electrode) in the dye-sensitized solar cell which concerns on this invention. It is a schematic sectional drawing which shows the 2nd process of an example which produces the board | substrate provided with the electrode which functions as a 1st electrode (window electrode) in the dye-sensitized solar cell which concerns on this invention. It is a schematic sectional drawing which follows the BB line shown in FIG. It is a schematic sectional drawing which shows the 1st process of an example which produces the board | substrate which provided the electrode which functions as a 2nd electrode (counter electrode) in the dye-sensitized solar cell which concerns on this invention. It is a schematic sectional drawing which follows the CC line shown in FIG. It is a schematic sectional drawing which shows the process of putting an electrolyte layer between the 1st electrode (window electrode) and the 2nd electrode (counter electrode) in the dye-sensitized solar cell which concerns on this invention, and bonding both electrodes. It is a schematic sectional drawing which bonds a 1st electrode (window electrode) and a 2nd electrode (counter electrode) in a dye-sensitized solar cell concerning the present invention, and applies a ultrasonic wave locally and shows a heating process. It is a figure which shows an example of the ultrasonic bonding apparatus which ultrasonically welds. It is a schematic sectional drawing which shows the structure of the conventional dye-sensitized solar cell.

Explanation of symbols

α first region, β second region, γ third region, 1st substrate, 2 transparent conductive film (first electrode), 3 porous oxide semiconductor layer, 4th substrate, 5 metal thin film (1st) 2 electrodes), 6 electrolyte layer, 7 recess, 8 window electrode substrate, 9 counter electrode substrate, 10 dye-sensitized solar cell, 11 bonding portion, 12 ultrasonic bonding member.

Claims (5)

A first electrode that has a porous oxide semiconductor layer carrying a sensitizing dye and functions as a window electrode, and is disposed at least partially opposite to the first electrode via an electrolyte layer A dye-sensitized solar cell comprising a second electrode,
The first base material on which the first electrode is provided and the second base material on which the second electrode is provided are, in the overlapping direction, a first region sandwiching the electrolyte layer, the first base material and / or the second base material. And a second region having a recess on the outer surface of the material, and the second region is disposed so as to surround the first region.   The dye-sensitized solar cell according to claim 1, further comprising a third region having a gap between the substrates so as to surround the second region.   3. The dye-sensitized solar cell according to claim 1, wherein the members constituting the first base material and the second base material are made of a material through which an ultrasonic wave passes.   The dye-sensitized solar cell according to claim 1 or 2, wherein the bonding interface of the second region is welded. Variation in reflectance obtained when observing the first region with light having a main absorption of Ru dye of 550 nm through the first substrate or the second electrode is within 50% within one cell. The dye-sensitized solar cell according to claim 1.

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