JP2008192441A - Dye-sensitized solar cell, generator utilizing the same, and output recovery method for dye-sensitized solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dye-sensitized solar cell that allows output recovery by eliminating deterioration in power generation efficiency with a relatively simple method. <P>SOLUTION: The dye-sensitized solar cell 120 is provided with a light-transmitting first substrate 13, a second substrate 25 arranged at a position opposite to the first substrate 13, a light-transmitting conductive layer 14, a semiconductor electrode 15, and a catalyst electrode 23. A cell space 32 exists between the first substrate 13 and the second substrate 25 while an electrolytic solution 33 is filled therein. An output recovery electrode 41, provided separately from the semiconductor electrode 15 and the catalyst electrode 23, is arranged on the side 22, opposite to the first substrate 13, in the second substrate 25 while facing the cell space 32. If a voltage is applied so that a current flows from the semiconductor electrode 15 toward the output recovery electrode 41 when power is not generated, output of the deteriorated dye-sensitized solar cell 120 is recovered. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a dye-sensitized solar cell that directly converts light energy into electric energy, a power generation device using the same, and a method for recovering the output of the dye-sensitized solar cell.

  At present, in solar power generation, solar cells using single crystal silicon, polycrystalline silicon, amorphous silicon, a combination of these with HIT (Heterojunction with Intrinsic Thin-layer), etc. have been put into practical use and have become the main technology. These solar cells have excellent photoelectric conversion efficiency (power generation efficiency) of nearly 20%. However, silicon-based solar cells have a high energy cost for material production, have many problems in terms of environmental impact, and have limitations in terms of price and material supply. On the other hand, in recent years, a dye-sensitized solar cell proposed by Gratzel et al. Has attracted attention as an inexpensive solar cell (see, for example, Non-Patent Document 1 and Patent Document 1). The dye-sensitized solar cell has a structure in which an electrolytic solution is interposed between a titania porous electrode carrying a sensitizing dye and a counter electrode. This type of dye-sensitized solar cell has the demerit that the photoelectric conversion efficiency is lower than the current silicon-based solar cell, but has the advantage that the cost can be significantly reduced in terms of materials and manufacturing method. Yes.

Here, the power generation mechanism of the dye-sensitized solar cell will be briefly described. For example, in the case of a dye-sensitized solar cell using a redox pair (I ⁻ and I ₃ ⁻ etc.) as an electrolytic solution, the light is sensitized when it hits the titania porous electrode during power generation such as daytime. The dye absorbs and emits electrons into the titania porous electrode. At this time, the holes left in the sensitizing dye, iodide ion (I ^-) to oxidize and triiodide (I 3 ^_-) changing to. In addition, the electrons emitted into the titania porous electrode move to the counter electrode through the circuit, where the triiodide ions (I ₃ ⁻ ) are reduced to iodide ions (I ⁻ ). Then, the light energy is converted into electric energy by the continuous occurrence of this cycle.

  However, when the dye-sensitized solar cell is continuously in a power generation state for a long period of time, the ratio of the redox pair in the electrolyte is biased, which causes the deterioration of the battery characteristics (that is, the decrease in photoelectric conversion efficiency). It becomes. There are two possible reasons for this.

First reason: Although triiodide ions (I ₃ ⁻ ) and iodide ions (I ⁻ ) exist as redox pairs in the electrolyte, triiodide ions (I ₃ ⁻ ) is unevenly distributed, and iodide ions (I ⁻ ) are unevenly distributed in the vicinity of the counter electrode, so that the conductivity of the electrolytic solution is lowered.

Second reason: When light contains ultraviolet light, the ultraviolet light induces a photocatalytic reaction at the interface between the titania porous electrode and the electrolytic solution, thereby reducing iodide ions (I ⁻ ), This is because the ion ratio in the electrolyte is shifted to a state where iodide ions (I ⁻ ) are rich.
Nature (Vol. 353, pp. 737-740, 1991) Japanese Patent Laid-Open No. 1-220380

  Therefore, in a dye-sensitized solar cell, it is desired to recover the deteriorated characteristics by some method, but a specific and practical effective method for that purpose has not been proposed.

  For reference, in a solar cell using an organic solvent containing an electrolyte as an electrolytic solution, a method for improving photoelectric conversion efficiency has been conventionally proposed by immersing a titania electrode in an aqueous titanium chloride solution and then firing again. (See, for example, Non-Patent Document 2: J. Am. Ceram. Soc. 1997, 80, 3157). However, since this method requires disassembly and assembly of the solar cell, it requires a very troublesome work and is not practical.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a dye-sensitized solar cell that can recover the output by eliminating the decrease in photoelectric conversion efficiency by a relatively simple method. It is an object of the present invention to provide a power generation apparatus and a method for recovering the output of a dye-sensitized solar cell.

  The inventors of the present invention conducted intensive research to solve the above problems, and came up with an unprecedented electrochemical treatment as a technique for restoring the characteristics of a dye-sensitized solar cell. The new output recovery method has been completed. In addition, a dye-sensitized solar cell having a structure suitable for executing this novel output recovery method has also been completed.

  That is, as means (means 1) for solving the above-described problems, a first base (13) having translucency and a second base (25) disposed at a position facing the first base (13). ), A translucent conductive layer (14) provided on the side (12) of the first base (13) facing the second base (25), and on the translucent conductive layer (14). A semiconductor electrode (15) containing a sensitizing dye, a catalyst electrode (23) provided on a side (22) of the second base (25) facing the first base, and the first base (13) and an electrolytic solution (33) filled in a cell space (32) existing between the second substrate (25), and the semiconductor electrode (15) disposed facing the cell space (32). And an output recovery electrode (41) provided separately from the catalyst electrode (23). There is a dye-sensitized solar cells (100,120,140,160).

  Therefore, according to the invention described in the means 1, the output recovery electrode is provided separately from the semiconductor electrode and the catalyst electrode. It can be used in such a way that current flows. And, if you use it like this, the reaction opposite to that during power generation occurs due to electrochemical action, so the bias of ions in the electrolyte can be eliminated and the state of ions can be returned to the initial state. Become. Therefore, the output can be recovered by eliminating the decrease in photoelectric conversion efficiency by a relatively simple method without disassembling and assembling the apparatus. Therefore, it is possible to provide a dye-sensitized solar cell that is more practical than conventional products.

  Since the first base having translucency is disposed on the side where light enters during use, the first base is formed using a translucent material such as glass or a resin sheet. When the first substrate is formed of a resin sheet, the resin used for forming the resin sheet includes various thermoplastic resins such as polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyphenylene sulfide, polycarbonate, polysulfone, and polyethyleneidene norbornene. Is mentioned. The thickness of the first substrate varies depending on the material and is not particularly limited. However, it is preferable that the following transmittance, which is a light-transmitting index, is 60% to 99%, particularly 85% to 99%. . Here, translucency means that the transmittance of visible light having a wavelength of 400 nm to 900 nm is 10% or more. This transmittance is preferably 60% or more, particularly 85% or more. Hereinafter, the meaning of translucency and preferable transmittance are all the same.

  Transmittance (%) = (transmitted light amount / incident light amount) × 100

The “translucent conductive layer” is provided on the side of the first base facing the second base. The translucent conductive layer only needs to have translucency and conductivity, and the material is not particularly limited. Examples of the translucent conductive layer include a thin film made of a conductive oxide, a carbon thin film, and the like. Examples of the conductive oxide include indium oxide, tin-doped indium oxide, tin oxide, and fluorine-doped tin oxide (FTO). The thickness of the translucent conductive layer varies depending on the material and is not particularly limited, but the surface resistance is preferably 100 Ω / cm ² or less, particularly 1 Ω / cm ² or more and 10 Ω / cm ² or less. .

  In addition, the translucency meaning and preferable visible light transmittance | permeability of this translucent conductive layer are the same as that of the translucent board | substrate.

  The “semiconductor electrode” is provided on the translucent conductive layer and contains a sensitizing dye. In other words, the semiconductor electrode is provided on the side of the first substrate facing the second substrate, and is disposed facing the cell space.

  This semiconductor electrode has, for example, a structure in which a sensitizing dye is attached to a porous electrode substrate. The porous electrode substrate can be formed of a metal oxide, a metal sulfide or the like. Examples of the metal oxide include titania, tin oxide, zinc oxide, niobium oxide such as niobium pentoxide, tantalum oxide, and zirconia. Also, double oxides such as strontium titanate, calcium titanate, and barium titanate can be used. Furthermore, examples of the metal sulfide include zinc sulfide, lead sulfide, and bismuth sulfide.

  The method for forming the porous electrode substrate is not particularly limited. For example, a paste containing semiconductor fine particles such as a metal oxide or a metal sulfide is applied to the surface of a light-transmitting substrate or the like to form an unfired porous electrode substrate. After forming, a procedure of firing can be employed. The method for applying the paste is not particularly limited, and specific examples thereof include a screen printing method, a doctor blade method, a squeegee method, and a spin coating method. The semiconductor electrode substrate thus formed has a form of an aggregate formed by aggregating semiconductor fine particles.

  The firing conditions in this case are not particularly limited. For example, the firing temperature is set to 400 ° C. to 600 ° C., particularly 450 ° C. to 650 ° C., and the firing time is 10 minutes to 300 minutes, particularly 20 minutes to 40 minutes. It may be set to a minute or less. The firing atmosphere may be an oxidizing atmosphere such as an air atmosphere, or may be an inert atmosphere such as a rare gas such as argon or a nitrogen gas.

  The thickness of the semiconductor electrode is not particularly limited, but may be from 0.1 μm to 100 μm, preferably from 1 μm to 50 μm, particularly from 2 μm to 40 μm, and more preferably from 5 μm to 30 μm. If this thickness is in the range of 0.1 μm or more and 100 μm or less, photoelectric conversion is sufficiently performed, and power generation efficiency can be improved. The semiconductor electrode is preferably heat-treated in order to improve its strength and adhesion with the first substrate. The temperature and time of the heat treatment are not particularly limited, but the heat treatment temperature is preferably 40 ° C. or more and 700 ° C. or less, particularly preferably 100 ° C. or more and 500 ° C. or less, and the heat treatment time is 10 minutes or more and 10 hours or less, particularly 20 minutes or more. 5 hours or less is preferable. In addition, when using a resin sheet as a 1st base | substrate, it is preferable to heat-process at suitable temperature so that resin may not deteriorate with a heat | fever.

  The “sensitizing dye” possessed by the semiconductor electrode plays a role of improving the photoelectric conversion action, and specifically, complex dyes and organic dyes that improve the photoelectric conversion action can be used. Examples of complex dyes include metal complex dyes, and examples of organic dyes include polymethine dyes and merocyanine dyes. Examples of the metal complex dye include a ruthenium complex dye and an osmium complex dye, and a ruthenium complex dye is particularly preferable. Furthermore, in order to expand the wavelength range in which photoelectric conversion is performed and improve the photoelectric conversion efficiency, two or more sensitizing dyes having different wavelength ranges in which a sensitizing action is exhibited can be used in combination. In this case, it is preferable to set the type of sensitizing dye to be used in combination and the amount ratio thereof depending on the wavelength range and intensity distribution of the irradiated light. The sensitizing dye preferably has a functional group for bonding to the semiconductor electrode. Examples of this functional group include a carboxyl group, a sulfonic acid group, and a cyano group.

  The method for attaching the sensitizing dye to the porous electrode substrate is not particularly limited. For example, after immersing the porous electrode substrate in a solution in which the sensitizing dye is dissolved in the organic solvent and impregnating the solution, the organic solvent The method of removing can be employed. A method of removing the organic solvent after applying this solution to the porous electrode substrate can also be employed. Examples of the solution coating method in this case include a wire bar method, a slide hopper method, an extrusion method, a curtain coating method, a spin coating method, and a spray coating method. Furthermore, this solution can also be applied by a printing method such as offset printing, gravure printing or screen printing.

  The adhesion amount of the sensitizing dye is preferably 0.01 mmol or more and 1 mmol or less, particularly 0.5 mmol or more and 1 mmol or less with respect to the semiconductor electrode 15. If the adhesion amount is set within a range of 0.01 mmol or more and 1 mmol or less, photoelectric conversion is efficiently performed in the semiconductor electrode. Moreover, if the sensitizing dye that has not adhered to the semiconductor electrode is liberated around the electrode, the conversion efficiency may be lowered. For this reason, it is preferable to remove the excess sensitizing dye by washing the semiconductor electrode after the treatment for attaching the sensitizing dye. This removal can be performed by washing with a polar solvent such as acetonitrile and an organic solvent such as an alcohol solvent using a washing tank. In order to attach a large amount of sensitizing dye to the electrode substrate, it is preferable to heat the semiconductor electrode and perform a treatment such as dipping or coating. In this case, in order to avoid water adsorbing on the surface of the semiconductor electrode, it is preferable to perform the treatment promptly at 40 ° C. or more and 80 ° C. or less without heating to room temperature after heating.

  On the other hand, the “second substrate” arranged to face the first substrate has a catalyst electrode on the side facing the first substrate.

  The second substrate may have a light-transmitting property or may not have a light-transmitting property. As the second substrate having translucency, for example, a glass substrate or a resin substrate can be used. For example, a ceramic substrate can be used as the second substrate that does not have translucency. The ceramic substrate has high mechanical strength, and this substrate can serve as a support substrate to provide a dye-sensitized solar cell having excellent durability. The ceramic used for forming the ceramic substrate is not particularly limited. For example, various ceramics such as oxide ceramics, nitride ceramics, and carbide ceramics can be used. Examples of the oxide ceramic include alumina, mullite, zirconia and the like. Examples of the nitride ceramic include silicon nitride, sialon, titanium nitride, and aluminum nitride. Further, examples of the carbide-based ceramic include silicon carbide, titanium carbide, and aluminum carbide. As the ceramic, alumina, silicon nitride, zirconia and the like are preferable, and alumina is particularly preferable. The reason is that in addition to being excellent in mechanical strength, it has suitable insulating properties, so that it is also suitable as a support for forming electrodes, conductive layers and the like.

  When the second substrate is a ceramic substrate, the thickness is not particularly limited, but can be 100 μm or more and 5 mm or less, 300 μm or more and 4 mm or less, particularly 500 μm or more and 2 mm or less. If the thickness of the ceramic substrate is 100 μm or more, sufficient mechanical strength required as a support substrate can be imparted, and therefore, by using this, a dye-sensitized solar cell having excellent durability can be obtained.

  The “catalyst electrode” provided on the side of the second substrate facing the first substrate may be provided directly on the surface of the second substrate, or indirectly through the second substrate-side conductive layer. May be. It does not specifically limit as a 2nd base | substrate side conductive layer, The material will not ask | require if it has electroconductivity. In this case, for example, a light-transmitting conductive layer provided on the side of the first base facing the second base may be used as the second base-side conductive layer.

  This catalyst electrode can be formed of a substance having catalytic activity. Examples of the substance having catalytic activity include noble metals such as platinum, gold, and rhodium. Silver is also a noble metal, but is not preferred because of its low corrosion resistance to electrolytes and the like.

  Examples of substances having catalytic activity other than noble metals include carbon black. Any of the substances listed here has suitable conductivity. Since noble metals have catalytic activity and are electrochemically stable, they are suitable as a material for forming a catalyst electrode. Among them, platinum having high catalytic activity and high corrosion resistance to an electrolyte is particularly suitable.

  The thickness of the catalyst electrode is not particularly limited, but can be 3 nm or more and 10 μm or less, particularly 3 nm or more and 2 μm or less in both cases of single layer and multilayer. When the thickness of the catalyst electrode is in the range of 3 nm or more and 10 μm or less, a catalyst electrode having a sufficiently low resistance can be obtained.

  A catalytic electrode made of a substance having catalytic activity can be formed by applying a paste containing fine particles of a substance having catalytic activity to the surface of the second substrate or the surface of the second substrate-side conductive layer.

  Examples of the coating method include various methods such as a screen printing method, a doctor blade method, a squeegee method, and a spin coating method. Furthermore, this catalyst electrode can also be formed by depositing metal or the like on the surface of the second substrate or the surface of the second substrate-side conductive layer by sputtering, vapor deposition, ion plating, or the like.

  A conductor layer may be formed on the opposite side of the second base opposite to the first base, and the conductor on the side facing the first base and the opposite side of the side facing the first base. A via conductor that conducts to the conductor layer may be formed on the second base. Such a conductor layer and via conductor can be formed of a conductive material, and specifically, a metal paste containing metal particles such as aluminum, tungsten, titanium, nickel, etc. is printed and fired. Or the like.

  For example, a spacer is arranged between the first substrate and the second substrate, and as a result of the arrangement, a cell space is defined between the two. The material of the spacer is not particularly limited, and resin or glass can be used, but it is preferable to select a material having corrosion resistance. The thickness of the spacer is set to, for example, 10 μm or more and 100 μm or less, preferably 20 μm or more and 80 μm or less in order to form a cell space having a desired height.

  The “electrolytic solution” is filled in the cell space existing between the first base and the second base, and is interposed at least between the semiconductor electrode and the catalyst electrode. The electrolyte solution may be injected into the cell space from the first substrate side or from the second substrate side. In this case, it is preferable to provide an injection port on the side where it is easy to perforate and to inject the electrolytic solution from this injection port. One injection port may be provided, but another hole may be provided for venting air. Thus, if the hole for venting air is provided, the electrolyte can be injected more easily and reliably.

Examples of the electrolyte in the electrolytic solution include (1) I ₂ and iodide, (2) Br ₂ and bromide, (3) metal complexes such as ferrocyanate-ferricyanate, ferrocene-ferricinium ion, (4) Examples include electrolytes containing sulfur compounds such as sodium polysulfide and alkylthiol-alkyldisulfides, (5) viologen dyes, (6) hydroquinone-quinone, and the like. As iodide in (1) is, LiI, NaI, KI, CsI, metal iodide such as CaI _2, and tetraalkylammonium iodide, pyridinium iodide, imidazolium iodide iodine salt of quaternary ammonium compounds such as id, etc. Is mentioned. As the bromide in (2), LiBr, NaBr, KBr, CsBr, CaBr 2 , etc. of the metal bromide, and tetra-alkyl ammonium bromide, bromine salts of quaternary ammonium compounds such as pyridinium bromide and the like. Among these electrolytes, an electrolyte obtained by combining I ₂ and an iodine salt of a quaternary ammonium compound such as LiI, pyridinium iodide, and imidazolium iodide is particularly preferable. These electrolytes may use only 1 type and may use 2 or more types.

  The electrolyte can be blended in a solvent together with various additives and used as an electrolytic solution. This solvent preferably has a low viscosity, a high ion mobility, and sufficient ion conductivity. Examples of such solvents include (1) carbonates such as ethylene carbonate and propylene carbonate, (2) heterocyclic compounds such as 3-methyl-2-oxazolidinone, (3) ethers such as dioxane and diethyl ether, (4 ) Chain ethers such as ethylene glycol dialkyl ether, propylene glycol dialkyl ether, polyethylene glycol dialkyl ether, polypropylene glycol dialkyl ether, (5) methanol, ethanol, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, polyethylene glycol monoalkyl Monoalcohols such as ether and polypropylene glycol monoalkyl ether, (6) ethylene glycol, propylene glycol, polyethylene Polyhydric alcohols such as polyglycol, polypropylene glycol and glycerin, (7) nitriles such as acetonitrile, glutarodinitrile, methoxyacetonitrile, propionitrile, benzonitrile, and (8) aprotic such as dimethyl sulfoxide and sulfolane. Examples include polar substances. These solvent may use only 1 type and may use 2 or more types.

  Furthermore, a normal temperature molten salt can be used as the electrolyte, and in this case, an electrolyte can be obtained using a solvent. Also, the electrolyte can be used alone. As this room temperature molten salt, a room temperature molten salt of iodide can be used. Examples of room temperature molten salts of iodide include various room temperature molten salts such as imidazolium salts, pyridinium salts, pyrrolidinium salts, pyrazolidium salts, isothiazolidinium salts, isoxazolidinium salts, and the like. Of the room temperature molten salts of iodide, imidazolium salts are preferred. These room temperature molten salts can be used in combination of two or more different types.

  The “output recovery electrode” is an electrode mainly used for performing a process for recovering the output of the solar cell, and is disposed facing the cell space, and is provided separately from the semiconductor electrode and the catalyst electrode. It is done. In other words, the output recovery electrode is provided in a state of being electrically insulated from the semiconductor electrode and the catalyst electrode at least in the cell space.

  The output recovery electrode can be provided at any position as long as it faces the cell space. For example, the output recovery electrode is preferably provided at a position closer to the semiconductor electrode than the catalyst electrode. When the separation distance from the semiconductor electrode is shortened, the distance that ions move through the electrolyte during non-power generation is shortened, so that the ion bias can be efficiently eliminated in a short time. The separation distance is preferably 5 μm or more and 40 μm or less, and more preferably 5 μm or more and 20 μm or less. This is because if the separation distance is too small, the output recovery electrode may come into contact with the semiconductor electrode and short-circuit due to an assembly error or the like. On the other hand, if the separation distance is too large, the distance that ions move through the electrolyte during non-power generation is not sufficiently shortened.

  The output recovery electrode can be provided on either side of the first base or the second base, but in other words, it is preferably provided on the second base. If the output recovery electrode is provided on the first substrate side, it is necessary to provide a wiring structure on the first substrate side. In addition to blocking the light, the wiring structure reduces the area of the semiconductor electrode. There is a disadvantage that the photoelectric conversion efficiency is lowered. On the other hand, if the output recovery electrode is provided on the second substrate side, the disadvantage of light shielding due to the wiring structure is eliminated, so that a decrease in photoelectric conversion efficiency can be avoided.

  As a specific example of the structure in which the output recovery electrode is provided on the second base side, for example, a structure in which the output recovery electrode is provided on a convex portion protruding from the surface of the second base facing the first base. Is preferred. With this structure, the output recovery electrode can be disposed close to the semiconductor electrode so as to face the semiconductor electrode, and therefore ions can be efficiently moved during non-power generation.

  Such a convex portion is not particularly limited, and for example, it may be provided integrally with the second base body, or may be formed separately from the second base body. The protrusion amount of the convex portion with respect to the surface of the second base body facing the first base body is not particularly limited, but may be, for example, 50% to 90% of the height of the cell space.

  When the structure in which the output recovery electrode is provided on the second base side is adopted, the conductor layer and the via conductor are provided on the opposite side of the second base opposite to the first base, and the via conductor and the output recovery electrode are provided. You may make it conduct. With this configuration, the wiring can be drawn out from the output recovery electrode provided on the side of the second base facing the first base via the conductor layer and the via conductor. Accordingly, it is not necessary to form a large output recovery electrode along the plane direction in order to draw out the wiring, and therefore, it is easy to achieve miniaturization of the second base and hence miniaturization of the solar cell.

  The number and layout of the output recovery electrodes are not particularly limited. For example, it is preferable that a plurality of output recovery electrodes are provided in the form of dots. According to this configuration, ions can be reduced evenly during non-power generation and the bias can be eliminated, so that the ion state can be efficiently returned to the initial state.

  The output recovery electrode is not particularly limited as long as it has conductivity, but is preferably a catalyst electrode made of a material having catalytic activity to reduce ions in the electrolytic solution. The reason for this is that if it has catalytic activity, ions can be efficiently reduced during non-power generation to reliably eliminate the bias. The output recovery electrode in this case may be the same as that of the catalyst electrode, and can be formed of a substance having catalytic activity. Since specific examples of the electrode forming material are listed in the description of the catalyst electrode, they are omitted here. From the viewpoint of productivity and cost, the output recovery electrode is preferably formed in the same process using the same material as the catalyst electrode.

  As another means (means 2) for solving the above problems, the dye-sensitized solar cell (100, 120, 140, 160) described in means 1, the positive electrode side of the load (90), and the catalyst electrode A first circuit (C1) electrically connecting the negative electrode side of the load (90) and the semiconductor electrode (15), and a positive electrode side of the DC power source (91) A second circuit (C2) for electrically connecting the output recovery electrode (41) and connecting a negative electrode side of a DC power source (91) and the semiconductor electrode (15); and the first circuit (C1). And a switch (S11, S12) for selectively switching one of the second circuits (C2) to a closed state.

  Therefore, according to the invention described in the means 2, at the time of power generation, the switch is switched so that the first circuit is closed, so that electric power is supplied from the catalyst electrode side to the load. As a result of switching the switch so that the second circuit is closed during non-power generation, power is supplied from the DC power source to the output recovery electrode side. At this time, since a current flows in the electrolyte solution in the cell space in the opposite direction to that during power generation, a reaction opposite to that during power generation occurs due to electrochemical action. Therefore, the bias of ions in the electrolytic solution is eliminated, and the ion state can be returned to the initial state. Therefore, the output can be recovered by eliminating the decrease in photoelectric conversion efficiency by a relatively simple method without disassembling and assembling the apparatus. For this reason, it is possible to provide a power generator that is more practical than conventional products.

  As another means (means 3) for solving the above-mentioned problem, there is a method for recovering the output when the dye-sensitized solar cell (1, 100, 120, 140, 160) is deteriorated, and during non-power generation There is an output recovery method for a dye-sensitized solar cell, in which a voltage is applied so that a current flows in a direction opposite to that during power generation.

  Therefore, according to the invention described in the means 3, when non-power generation is performed, a voltage is applied in a direction opposite to that during power generation. It is possible to return to the initial state. Therefore, the output can be recovered by eliminating the decrease in photoelectric conversion efficiency by a relatively simple method without disassembling and assembling the apparatus. When performing such output recovery, a voltage may be applied to the output recovery electrode provided separately from the semiconductor electrode and the catalyst electrode, but the voltage is applied to the existing catalyst electrode without providing the output recovery electrode. May be applied.

  Another means (means 4) for solving the above problem is a method of recovering the output when the dye-sensitized solar cell (100, 120, 140, 160) described in means 1 is deteriorated, There is an output recovery method for a dye-sensitized solar cell, wherein a voltage is applied so that a current flows from the semiconductor electrode (15) toward the output recovery electrode (41) during non-power generation.

  Therefore, according to the invention described in the means 4, when non-power generation is performed, a voltage is applied in a direction opposite to that during power generation. It is possible to return to the initial state. Therefore, the output can be recovered by eliminating the decrease in photoelectric conversion efficiency by a relatively simple method without disassembling and assembling the apparatus. In addition, the output can be efficiently recovered by using the output recovery electrode provided separately from the catalyst electrode.

  Here, “degradation of the dye-sensitized solar cell” refers to a state in which the output is lower than the output value (initial output value) of the dye-sensitized solar cell at the time of product shipment. The output recovery by this method is performed, for example, when the output is 40% or less or 60% or less of the initial output value.

Voltage to be applied during the non power is appropriately set according to the degree of degradation of the solar cell, for example, 1 mA / cm ² or more 200 mA / cm ² or less current than 100 seconds with respect to the area of the semiconductor electrode It is preferable to apply a voltage so as to flow. If a voltage is applied with the current density and energization time set in this range, the degraded output can be reliably recovered even in a relatively short time. If the current density is less than 1 mA / cm ² , the ion bias may not be sufficiently eliminated. Further, if the current density exceeds 200 mA / cm ² or the energization time exceeds 100 seconds, electric energy that is larger than necessary is input, which is wasteful and is not preferable. Further, setting so that an excessive current flows is not preferable because it not only causes a decrease in the performance of the solar cell but also causes a breakdown.

[First Embodiment]

  Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS.

  FIG. 1 shows a dye-sensitized solar cell 1 used in the present embodiment. The dye-sensitized solar cell 1 has a structure in which a first base 13 and a second base 25 are arranged to face each other with a spacer 31 interposed therebetween. A cell space 32 is formed between the first base 13 and the second base 25, and the cell space is filled with an electrolytic solution 33. On the side 12 of the first base 13 having translucency facing the second base 25, the translucent conductive layer 14 is formed over almost the entire surface. Further, a semiconductor electrode 15 containing a sensitizing dye is provided on the translucent conductive layer 14. On the other hand, a second substrate-side conductive layer 24 is formed on almost the entire surface of the second substrate 25 having translucency on the side 22 facing the first substrate 13. A catalyst electrode 23 is provided on the second base-side conductive layer 24 so as to face the semiconductor electrode 15. The catalyst electrode 23 may be formed over the entire inner surface 22 or may be formed in a part thereof. The semiconductor electrode 15 and the catalyst electrode 23 are both arranged facing the cell space 32, and as a result, are exposed to the electrolytic solution 33 filled in the cell space 32. In the present embodiment, the semiconductor electrode 23 and the output recovery electrode are integrated.

  2 and 3 show a power generation device including the dye-sensitized solar cell 1 as a constituent element. This power generator is constituted by the dye-sensitized solar cell 1, the load 90, the DC power supply 91, and the switch S1 shown in FIG. The catalyst electrode 23 is electrically connected to the first contact T1 of the switch S1. The second contact T2 of the switch S1 is electrically connected to the positive electrode side of the load 90, and the third contact T3 of the switch S1 is electrically connected to the positive electrode side of the DC power supply 91. On the other hand, the semiconductor electrode 15 is electrically connected to the negative electrode side of the load 90 and the negative electrode side of the DC power supply 91. As a result of such connection, a first circuit C1 that connects the dye-sensitized solar cell 1 and the load 90 to each other, and a second circuit C2 that connects the dye-sensitized solar cell 1 and the DC power supply 91 to each other are provided. Is formed. When the switch S1 is switched and the first contact T1 and the second contact T2 are closed (see FIG. 2), the first circuit C1 is closed and the second circuit C2 is opened, and the current is supplied from the dye-sensitized solar cell 1 to the load 90. Is to be supplied. Conversely, when the switch S1 is switched to close the first contact T1 and the third contact T3 (see FIG. 3), the first circuit C1 is opened and the second circuit C2 is closed. A current is supplied to the battery 1.

  Next, the preparation procedure of the dye-sensitized solar cell 1 of the present embodiment will be described.

  (1) Production of the first base 13, the translucent conductive layer 14, and the semiconductor electrode 15

  First, a first base 13 having translucency (a glass substrate manufactured by Nippon Sheet Glass Co., Ltd., length 25 mm, width 15 mm, thickness 1 mm) is prepared, and the entire surface of one side of the first base 13 having translucency is formed from FTO. A transparent conductive layer 14 having a thickness of 300 nm was formed. Next, a paste (Ti-Nanoxide D / SP 13 nm / 300 nm) containing titania particles having a particle size of 10 nm to 300 nm is screen-printed on the light-transmitting conductive layer 14 of the first substrate 13 having a light-transmitting property. Was applied to form a coating film having a thickness of 20 μm. After that, preliminary drying was performed at 120 ° C. for 30 minutes, and then, the porous electrode substrate for producing the semiconductor electrode 15 was formed by holding and baking at 500 ° C. for 30 minutes using a muffle furnace.

On the other hand, titanium tetrachloride was dissolved in ice-cooled water to prepare an aqueous solution having a concentration of 0.05 mol / liter. Thereafter, the first substrate 13 having the above-described translucency with the porous electrode substrate formed thereon is immersed in the aqueous titanium tetrachloride solution, and the aqueous solution is heated and held at 70 ° C. for 30 minutes to perform the titanium chloride treatment. It was. Next, the treated first substrate 13 having translucency was taken out of the aqueous solution, washed sufficiently with distilled water, and dried at room temperature for 30 minutes. Thereafter, the porous electrode substrate treated with titanium chloride was fired again by holding at 500 ° C. for 30 minutes using a muffle furnace.
Further, a ruthenium complex (trade name “N-719” manufactured by Kojima Chemical Co., Ltd.) is dissolved in a mixed solvent of acetonitrile and tert-butanol, and an acetonitrile / tert-butanol solution having a concentration of 5 × 10 ⁻⁴ mol / liter is obtained. Prepared. Next, the porous electrode substrate treated with titanium chloride and the first substrate 13 having translucency were immersed in this ruthenium complex solution for 18 hours. As a result, a ruthenium complex as a sensitizing dye was attached to the porous electrode substrate to form a semiconductor electrode 15 having a thickness of 20 μm.

  (2) Production of second substrate 25, second substrate-side conductive layer 24, and catalyst electrode 23

  First, a second substrate 25 having translucency (a glass substrate manufactured by Nippon Sheet Glass Co., Ltd., length 25 mm, width 15 mm, thickness 1 mm) is prepared, and the entire surface of one side of the second substrate 25 having translucency is applied from the FTO. A second base-side conductive layer 24 having a thickness of 300 nm was formed. Next, platinum (Pt) was deposited on the second substrate-side conductive layer 24 by sputtering to form a catalyst electrode 23 having a thickness of 200 nm. Here, both the second base 25 having translucency and the second base-side conductive layer 24 have translucency. However, since the translucency is not necessarily required, a material having no translucency is used. They may be used to form these.

  (3) Bonding of substrates

In the second base 25 having translucency with an electrolyte solution injection hole, a spacer 31 (made by Mitsui DuPont Polychemical Co., Ltd., trade name) made of a thermoplastic resin is formed on a portion where the catalyst electrode 23 is not formed. “High Milan 1702”). Then, the 1st base | substrate 13 which has translucency was arrange | positioned so that the semiconductor electrode 15 might oppose the catalyst electrode 23, and thermocompression bonding was performed at 100 degreeC for 4 second, and it sealed. Next, an electrolyte solution was injected from a hole opened on the counter electrode side, and then sealed with a UV curable resin, whereby the dye-sensitized solar cell 1 shown in FIG. 1 was completed. In the present embodiment, as the iodine electrolyte solution 33, in propylene carbonate as an organic solvent, 1.5 moles of _{I 2,} 0.1 mol of LiI, 0.5 mole 4-tert-butyl pyridine, dimethyl propyl It was decided to use one prepared by mixing 0.6 mole of imidazolium iodide.
Next, the produced dye-sensitized solar cell 1 was wired as shown in FIGS. 2 and 3 to constitute a power generation device, which was used by setting it in a place exposed to sunlight.

First, in the daytime when the sunlight hits, the switch S1 is switched to the state shown in FIG. 2 to close the first circuit C1. The light incident from the side of the first base 13 opposite to the side 12 facing the second base 25 passes through the light-transmitting first base 13 and the light-transmitting conductive layer 14 and reaches the semiconductor electrode 15. Then, in the semiconductor electrode 15, the sensitizing dye absorbs light and emits electrons into the semiconductor electrode 15. At this time, the holes left in the sensitizing dye, iodide ion (I ^-) to oxidize and triiodide (I 3 ^_-) changing to. On the other hand, electrons move to the catalyst electrode 23, which is the counter electrode, via a load 90 electrically connected to the semiconductor electrode 15. The electrons reduce triiodide ions (I ₃ ⁻ ) to iodide ions (I ⁻ ). As a result, in the dye-sensitized solar cell 1, light energy is converted into electric energy (that is, generated), and the generated electric power is supplied to the load 90. For example, if the load 90 is a storage battery, electricity can be stored there. During power generation, the catalyst electrode 23 side has a high potential and the semiconductor electrode 15 side has a low potential.

And when the dye-sensitized solar cell 1 deteriorates, the output is recovered as follows. In this case, the switch S1 is switched to close the second circuit C2, and a non-power generation state is set. Then, as a result of electrically connecting the DC power supply 91 instead of the load 90, a voltage is applied so that a current flows in a direction opposite to that during power generation. That is, a current is supplied from the semiconductor electrode 15 side to the catalyst electrode 23 via the DC power supply 91, whereby the catalyst electrode 23 side becomes a low potential and the semiconductor electrode 15 side becomes a high potential. In the present embodiment, the voltage is applied so that a current of about 120 mA / cm ² flows for about 5 seconds with respect to the area of the semiconductor electrode 15.

Then, electrons move from the DC power supply 91 to the semiconductor electrode 15, and the electrons reduce triiodide ions (I ₃ ⁻ ) and convert them into iodide ions (I ⁻ ). On the other hand, holes are generated at the catalyst electrode 23, the hole is iodide ion changing to (I ^- _-) oxidation to triiodide ions (I ^3). That is, an electrochemical reaction opposite to that during power generation occurs.

  Therefore, according to the present embodiment, the following effects can be obtained.

(1) As described above, when non-power generation is performed, a reverse electrochemical reaction occurs when a voltage is applied in the direction opposite to that during power generation, thereby eliminating the bias of the redox pair in the iodine electrolyte solution 33. be able to. As a result, the ion state can be returned to the initial state. Therefore, the output can be recovered by eliminating the decrease in photoelectric conversion efficiency by a relatively simple method without disassembling and assembling the apparatus.
[Second Embodiment]

  Next, a second embodiment of the present invention will be described in detail with reference to FIGS. Note that description of parts common to the first embodiment will be simplified, and differences will be mainly described.

  4 and 5 show a dye-sensitized solar cell 100 used in the present embodiment. Compared with the first embodiment, in the dye-sensitized solar cell 100, a pair of light-transmitting first base 13 on the side 12 facing the second base 25 has a pair of parallel extensions at the center. An insulating groove 102 is formed. Between the pair of insulating grooves 102, an output recovery electrode 41 made of a platinum catalyst electrode is formed in a band shape. The output recovery electrode 41 is also arranged facing the cell space 32, and as a result, is exposed to the electrolytic solution 33 filled in the cell space 32. Semiconductor electrodes 15 are disposed on both sides of the output recovery electrode 41. Therefore, although the semiconductor electrode 15 and the output recovery electrode 41 are adjacent to each other, they are insulated.

  6 and 7 show a power generation device including the dye-sensitized solar cell 100 as a constituent element. This power generator is constituted by the dye-sensitized solar cell 100 of FIG. 4, a load 90, a DC power source 91, and two switches S11 and S12. The catalyst electrode 23 is electrically connected to the first contact T1a of the switch S11. The second contact T1b of the switch S11 is electrically connected to the positive electrode side of the load 90. On the other hand, the semiconductor electrode 15 is electrically connected to the negative electrode side of the load 90 and the negative electrode side of the DC power supply 91. The output recovery electrode 41 is electrically connected to the first contact T2a of the switch S12. The second contact T2b of the switch S12 is electrically connected to the positive electrode side of the DC power supply 91. As a result of such connection, a first circuit C1 that connects the dye-sensitized solar cell 100 and the load 90 to each other, and a second circuit C2 that connects the dye-sensitized solar cell 1 and the DC power source 91 to each other are provided. Is formed.

  When the switch S11 is turned on to close the first contact T1a and the second contact T2a, and the switch S12 is turned off to open the first contact T2a and the second contact T2b (see FIG. 6), the first circuit C1. Is closed and the second circuit C2 is opened, and current is supplied from the dye-sensitized solar cell 100 to the load 90. Conversely, when the switch S11 is turned off to open the first contact T1a and the second contact T2a, and the switch S12 is turned on to close the first contact T2a and the second contact T2b (see FIG. 7), The first circuit C1 is opened and the second circuit C2 is closed, and current is supplied from the DC power supply 91 to the output recovery electrode 41 of the dye-sensitized solar cell 100.

  Next, a manufacturing procedure of the dye-sensitized solar cell 100 of this embodiment will be described. The second substrate 25, the second substrate-side conductive layer 24, the production of the catalyst electrode 23, and the bonding between the two substrates are the same as in the first embodiment, and therefore the first substrate 13, the translucent conductive layer 14. Only the fabrication of the semiconductor electrode 15 will be described in detail.

  (1) Production of the first base 13, the translucent conductive layer 14, and the semiconductor electrode 15

  First, a first base 13 having translucency (a glass substrate manufactured by Nippon Sheet Glass Co., Ltd., length 25 mm, width 15 mm, thickness 1 mm) is prepared, and the entire surface of one side of the first base 13 having translucency is formed from FTO. A transparent conductive layer 14 having a thickness of 300 nm was formed. Next, groove processing was performed on the side 12 of the first base 13 having translucency on which the translucent conductive layer 14 was formed, facing the second base 25, and a pair of parallel insulating grooves 102 was formed. After the groove processing step, the translucent conductive layer 14 positioned between the pair of insulating grooves 102 is separated from the translucent conductive layer 14 on both sides thereof. Next, a predetermined mask is provided on the side 12 of the first base 13 having translucency facing the second base 25 to cover the outer region of the pair of insulating grooves 102. In this state, platinum (Pt ) Was deposited to form an output recovery electrode 41 having a thickness of 200 nm. Next, after removing the mask, a semiconductor electrode 15 having a thickness of 20 μm was formed in the outer region according to the method of the first embodiment.

  And the 2nd base | substrate 25 produced according to 1st Embodiment and this 1st base | substrate 13 are joined, the iodine electrolyte solution 33 is inject | poured, and the dye-sensitized solar cell 100 shown in FIG. Completed.

  Next, the produced dye-sensitized solar cell 100 was wired as shown in FIG. 6 and FIG. 7 to constitute a power generation device, which was used in a place exposed to sunlight.

  First, during the daytime when sunlight is applied, the switches S11 and S12 are switched to close the first circuit C1 as shown in FIG. At this time, the electrochemical reaction similar to that in the first embodiment proceeds, and light energy is converted into electrical energy in the dye-sensitized solar cell 100. During such power generation, the catalyst electrode 23 side has a high potential and the semiconductor electrode 15 side has a low potential. During power generation, the output recovery electrode 41 is not electrically connected to either the semiconductor electrode 15 or the catalyst electrode 23 and is disconnected, so that no current flows.

When the dye-sensitized solar cell 100 is deteriorated, its output is recovered as follows. In this case, as shown in FIG. 7, the switches S11 and S12 are switched to close the second circuit C2 and enter a non-power generation state. Then, as a result of electrically connecting the DC power supply 91 instead of the load 90, a voltage is applied so that a current flows in a direction opposite to that during power generation. That is, a current is supplied from the semiconductor electrode 15 side to the output recovery electrode 41 via the DC power supply 91, whereby the output recovery electrode 41 side has a low potential and the semiconductor electrode 15 side has a high potential. In this embodiment, a voltage is applied so that a current of about 60 mA / cm ² flows for about 1 second with respect to the area of the semiconductor electrode 15.

Then, electrons move from the DC power supply 91 to the semiconductor electrode 15, and the electrons reduce triiodide ions (I ₃ ⁻ ) and convert them into iodide ions (I ⁻ ). On the other hand, holes are generated at the output recovery electrode 41, the hole is iodide ion changing to (I ^- _-) oxidation to triiodide ions (I ^3). That is, the electrochemical reaction opposite to that during power generation occurs in the semiconductor electrode 15.

  Therefore, according to the present embodiment, the following effects can be obtained.

  (1) As described above, when non-power generation is performed, a reverse electrochemical reaction occurs when a voltage is applied in the direction opposite to that during power generation, thereby eliminating the bias of the redox pair in the iodine electrolyte solution 33. be able to. As a result, the ion state can be returned to the initial state. Therefore, the output can be recovered by eliminating the decrease in photoelectric conversion efficiency by a relatively simple method without disassembling and assembling the apparatus. Incidentally, in this embodiment, it is possible to recover to about 70% of the initial output value by performing the recovery process under the above conditions when the output becomes 30% or less of the initial output value.

(2) Particularly in this embodiment, since the output recovery electrode 41 is on the side 12 of the first base 13 facing the second base 25 (in other words, on the same plane as the semiconductor electrode 15), the catalyst electrode 23 which is the counter electrode It is located closer to the semiconductor electrode 15 than. Therefore, compared with the structure of the first embodiment, the distance that ions move in the electrolyte during non-power generation is short. Moreover, the interelectrode resistance is reduced to about 1/20 to 1/30 as compared with the first embodiment. Therefore, it is possible to efficiently eliminate the ion bias in a short time.
[Third Embodiment]

  Next, a third embodiment of the present invention will be described in detail with reference to FIGS. Note that description of parts common to the first embodiment will be simplified, and differences will be mainly described.

  8 and 9 show the dye-sensitized solar cell 120 used in the present embodiment. Compared with the first embodiment, in this dye-sensitized solar cell 120, one insulating groove 122 is formed at the center of the second base 25 made of alumina on the side 22 facing the first base 13. Is formed. And the protrusion 121 (convex part) about 20 micrometers-30 micrometers in height extended in the strip | belt shape is provided in the bottom face of this insulating-groove part 122. As shown in FIG. On the upper surface of the ridge 121, an output recovery electrode 41 made of a platinum catalyst electrode is similarly formed in a strip shape. This output recovery electrode 41 is also arranged facing the cell space 32, and as a result, is exposed to the electrolytic solution 33 filled in the cell space 32. The catalyst electrode 23 is disposed on both sides of the output recovery electrode 41. Therefore, although the catalyst electrode 23 and the output recovery electrode 41 are adjacent to each other, they are insulated.

  10 and 11 show a power generation device including the dye-sensitized solar cell 120 as a constituent element. This power generator is constituted by the dye-sensitized solar cell 120 of FIG. 8, a load 90, a DC power source 91, and two switches S11 and S12. Since the mutual connection relationship is the same as that of the second embodiment, detailed description thereof is omitted.

  Next, a manufacturing procedure of the dye-sensitized solar cell 120 of this embodiment will be described. The first base 13, the translucent conductive layer 14, the semiconductor electrode 15 and the joining between the two bases are not different from those of the first embodiment. Therefore, the second base 25, the second base side conductive layer are the same. 24. Only the production of the catalyst electrode 23 will be described in detail.

  (2) Production of second substrate 25, second substrate-side conductive layer 24, and catalyst electrode 23

  First, a second substrate 25 (alumina substrate, length 25 mm, width 15 mm, thickness 1 mm) was prepared, and a groove was formed on the side 22 facing the first substrate 13 to form an insulating groove 122. Next, a conductive paste containing particles of conductive metal (aluminum, tungsten, titanium, nickel, etc.) is applied to the bottom surface of the insulating groove 122, and then the paste is fired at a predetermined temperature to have conductivity. A ridge 121 was formed. Instead of the coating method, for example, the protrusion 121 may be formed by a plating method, a sticking method, a stamp method, or the like. In addition, since the protrusion 121 of this embodiment does not necessarily have electroconductivity, you may form using nonelectroconductive materials, such as resin, glass, a ceramic. Next, platinum (Pt) is deposited on the side 22 of the second base 25 facing the first base 13 and the protrusions 121 by sputtering, so that the catalyst electrode 23 and the output recovery electrode 41 having a thickness of 200 nm are formed. Formed.

  And the 1st base | substrate 13 produced according to 1st Embodiment and this 2nd base | substrate 25 are joined, the iodine electrolyte solution 33 is inject | poured, and the dye-sensitized solar cell 120 shown in FIG. Completed.

  Next, the produced dye-sensitized solar cell 120 is wired as shown in FIGS. 10 and 11 to constitute a power generation device, which is set in a place exposed to sunlight, and is the same as in the second embodiment. Used.

  First, during the daytime when sunlight is applied, the switches S11 and S12 are switched to close the first circuit C1 as shown in FIG. At this time, the electrochemical reaction similar to that in the first embodiment proceeds, and light energy is converted into electrical energy in the dye-sensitized solar cell 120. During such power generation, the catalyst electrode 23 side has a high potential and the semiconductor electrode 15 side has a low potential. During power generation, the output recovery electrode 41 is not electrically connected to either the semiconductor electrode 15 or the catalyst electrode 23 and is disconnected, so that no current flows.

When the dye-sensitized solar cell 120 is deteriorated, its output is recovered as follows. In this case, as shown in FIG. 11, the switches S11 and S12 are switched to close the second circuit C2, and the power generation state is set. Then, as a result of electrically connecting the DC power supply 91 instead of the load 90, a voltage is applied so that a current flows in a direction opposite to that during power generation. That is, a current is supplied from the semiconductor electrode 15 side to the output recovery electrode 41 via the DC power supply 91, whereby the output recovery electrode 41 side has a low potential and the semiconductor electrode 15 side has a high potential. In the present embodiment, the voltage is applied so that a current of about 40 mA / cm ² flows for about 1 second with respect to the area of the semiconductor electrode 15.

Then, electrons move from the DC power supply 91 to the semiconductor electrode 15, and the electrons reduce triiodide ions (I ₃ ⁻ ) and convert them into iodide ions (I ⁻ ). On the other hand, holes are generated at the output recovery electrode 41, the hole is iodide ion changing to (I ^- _-) oxidation to triiodide ions (I ^3). That is, the electrochemical reaction opposite to that during power generation occurs in the semiconductor electrode 15.

  Therefore, according to the present embodiment, the following effects can be obtained.

  (1) As described above, when non-power generation is performed, a reverse electrochemical reaction occurs when a voltage is applied in the direction opposite to that during power generation, thereby eliminating the bias of the redox pair in the iodine electrolyte solution 33. be able to. As a result, the ion state can be returned to the initial state. Therefore, the output can be recovered by eliminating the decrease in photoelectric conversion efficiency by a relatively simple method without disassembling and assembling the apparatus. Incidentally, in this embodiment, it is possible to recover to about 70% of the initial output value by performing the recovery process under the above conditions when the output becomes 30% or less of the initial output value.

  (2) Particularly in this embodiment, the output recovery electrode 41 is on the side 22 of the second substrate 25 facing the first substrate 13 (in other words, the surface facing the semiconductor electrode 15), but the upper surface of the protrusion 121 By providing it, the semiconductor electrode 15 is located closer to the catalyst electrode 23 than the counter electrode. Therefore, compared with the structure of the first embodiment, the distance that ions move in the electrolyte during non-power generation is short. Moreover, the interelectrode resistance is reduced to about 1/20 to 1/30 as compared with the first embodiment. Therefore, it is possible to efficiently eliminate the ion bias in a short time.

(3) As a result of providing the output recovery electrode 41 on the second base 25 side, it is possible to avoid a decrease in photoelectric conversion efficiency due to light shielding by the wiring structure and a reduction in the area of the semiconductor electrode 15.
[Fourth Embodiment]

  Next, a fourth embodiment embodying the present invention will be described in detail with reference to FIGS.

  The dye-sensitized solar cell 140 used in the present embodiment is basically most similar to the third embodiment, but in the second substrate 25 made of alumina, on the side 22 facing the first substrate 13. A plurality of shallow circular recesses 145 are formed in a dotted pattern. In these depressions 145, there are provided projections 146 (convex portions) having a circular shape and a height of about 20 μm to 30 μm in plan view. An output recovery electrode 41 made of a platinum catalyst electrode is formed on the upper surface of the protrusion 146. This output recovery electrode 41 is also arranged facing the cell space 32, and as a result, is exposed to the electrolytic solution 33 filled in the cell space 32. A catalyst electrode 23 is disposed around the output recovery electrode 41. Therefore, although the catalyst electrode 23 and the output recovery electrode 41 are adjacent to each other, they are insulated. In addition, a via hole 141 that communicates the side 22 of the second substrate 25 made of alumina facing the first substrate 13 and the opposite side 27 of the side 22 facing the first substrate 13 is formed at the center of each recess 145. Is formed. In the via hole 141, a via conductor 142 made of the same conductive material as the protrusion 146 is provided. Such a via conductor 142 is formed simultaneously with the protrusion 146, for example. Specifically, a via hole 141 is formed in advance in the center of the depression 145, and then a conductive paste is applied and filled on the depression 145 and in the via hole 141, followed by firing. A conductor layer 143 is patterned on the opposite side 27 of the second substrate 25 made of alumina to the side 22 facing the first substrate 13, and the conductor layer 143 and the protrusion 146 (and output recovery) via the via conductor 142. The electrode 41). In addition, about the electric power generating apparatus which uses said dye-sensitized solar cell 140 as a component, since it is the same as that of 3rd Embodiment, description is abbreviate | omitted.

Therefore, even when the configuration of the present embodiment is adopted, the same effects as those of the third embodiment can be achieved. Further, the conductor layer 143 and the via conductor 142 on the opposite side 27 of the side 22 facing the first base 13 are provided, and the via conductor 142 and the output recovery electrode 41 are electrically connected. The wiring can be easily drawn out from the output recovery electrode 41 provided on the side 22 facing the one substrate 13. For this reason, it is not necessary to largely form the output recovery electrode 41 along the plane direction in order to draw out the wiring, and it becomes easy to achieve the miniaturization of the dye-sensitized solar cell 140.
[Fifth Embodiment]

  Next, a fifth embodiment of the present invention will be described in detail with reference to FIG.

  FIG. 14 shows a dye-sensitized solar cell 160 used in the present embodiment. Compared to the third embodiment, the dye-sensitized solar cell 160 is different in the following points. First, on the side 162 of the second substrate 25 made of alumina facing the first substrate 13, a protrusion 163 (projection) having a height of about 20 μm to 30 μm is provided at the center. The protrusion 163 can be easily formed by, for example, pressing an alumina green sheet from the outer surface with a jig or the like. On the upper surface of the protrusion 163, an output recovery electrode 41 made of a platinum catalyst electrode is similarly formed in a strip shape. This output recovery electrode 41 is also arranged facing the cell space 32, and as a result, is exposed to the electrolytic solution 33 filled in the cell space 32. The catalyst electrode 23 is disposed on both sides of the output recovery electrode 41. Therefore, although the catalyst electrode 23 and the output recovery electrode 41 are adjacent to each other, they are insulated. In addition, since it is the same as that of 3rd Embodiment about the electric power generating apparatus which uses said dye-sensitized solar cell 160 as a component, description is abbreviate | omitted.

  Therefore, even when the configuration of the present embodiment is adopted, the same effects as those of the third embodiment can be achieved.

  In addition, you may change embodiment of this invention as follows.

  -Although the 1st circuit C1 and 2nd circuit C2 which comprise the electric power generating apparatus in the said embodiment were provided separately from the solar cells 1,100,120,140,160, 100, 120, 140, 160 may be formed in a part. The same applies to the switches S1, S11, and S12.

  In the above embodiment, a storage battery is illustrated as the load 90, but a battery other than the storage battery (for example, various actuators or various sensors) may be used.

  In the above embodiment, the output recovery is performed using the current from the DC power supply 91 at the time of non-power generation. For example, instead of omitting the DC power supply 91, a part of the power stored in the storage battery as the load 90 May be used.

  In the above embodiment, nothing is covered on the opposite side of the first base 13 to the side 12 facing the second base 25. However, for example, the surface may be covered with an ultraviolet cut film.

1 is a schematic cross-sectional view showing a dye-sensitized solar cell according to a first embodiment that embodies the present invention. Schematic of a power generator (during power generation) including the dye-sensitized solar cell of the first embodiment. Schematic of the power generator (at the time of non-power generation) containing the dye-sensitized solar cell of 1st Embodiment. The schematic sectional drawing which shows the dye-sensitized solar cell of 2nd Embodiment. The figure which shows the inner surface of the 1st base | substrate of the dye-sensitized solar cell of 2nd Embodiment. Schematic of the electric power generating apparatus (at the time of electric power generation) containing the dye-sensitized solar cell of 2nd Embodiment. Schematic of the electric power generating apparatus (at the time of non-power generation) containing the dye-sensitized solar cell of 2nd Embodiment. The schematic sectional drawing which shows the dye-sensitized solar cell of 3rd Embodiment. The figure which shows the inner surface of the 2nd base | substrate of the dye-sensitized solar cell of 3rd Embodiment. Schematic of the electric power generating apparatus (at the time of electric power generation) containing the dye-sensitized solar cell of 3rd Embodiment. Schematic of the electric power generating apparatus (at the time of non-power generation) containing the dye-sensitized solar cell of 3rd Embodiment. The schematic sectional drawing which shows the dye-sensitized solar cell of 4th Embodiment. The figure which shows the inner surface of the 2nd base | substrate of the dye-sensitized solar cell of 4th Embodiment. The schematic sectional drawing which shows the dye-sensitized solar cell of 5th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 ... Side which opposes 2nd base | substrate of 1st base | substrate 13 ... 1st base | substrate which has translucency 14 ... Translucent conductive layer 15 ... Semiconductor electrode 22,162 ... Side which opposes 1st base | substrate of 2nd base | substrate 23 ... catalyst electrode 25 ... second substrate 27 ... opposite side of second substrate opposite to first substrate 32 ... cell space 33 ... electrolyte 41 ... output recovery electrode 90 ... load 91 ... DC power supply 100, 120, 140 , 160 ... Dye-sensitized solar cell 121 ... Projection as a convex part 142 ... Via conductor 143 ... Conductor layer 146 ... Projection as a convex part 163 ... Projection as a convex part C1 ... First circuit C2 ... Second circuit S11, S12 ... switch

Claims (11)

A first substrate having translucency;
A second base disposed at a position facing the first base;
A translucent conductive layer provided on a side of the first substrate facing the second substrate;
A semiconductor electrode containing a sensitizing dye provided on the translucent conductive layer;
A catalyst electrode provided on a side of the second substrate facing the first substrate;
An electrolyte filled in a cell space existing between the first substrate and the second substrate;
A dye-sensitized solar cell, which is disposed facing the cell space and includes an output recovery electrode provided separately from the semiconductor electrode and the catalyst electrode.   The dye-sensitized solar cell according to claim 1, wherein the output recovery electrode is provided at a position closer to the semiconductor electrode than the catalyst electrode.   3. The dye-sensitized dye according to claim 1, wherein the output recovery electrode is provided on a convex portion that protrudes on a side of the second substrate facing the first substrate. 4. Solar cell.   A conductor layer provided on the opposite side of the second base opposite to the side facing the first base, and a via conductor formed on the second base and conducting the conductor layer and the output electrode. Item 4. The dye-sensitized solar cell according to any one of Items 1 to 3.   5. The dye-sensitized solar cell according to claim 1, wherein a plurality of the output recovery electrodes are provided in the form of dots. 6.   The dye-sensitized solar cell according to claim 1 or 2, wherein the output recovery electrode is provided on the second substrate side.   The dye-sensitized solar according to any one of claims 1 to 6, wherein the output recovery electrode is a catalyst electrode made of a material having a catalytic activity for reducing ions in the electrolytic solution. battery. The dye-sensitized solar cell according to any one of claims 1 to 7,
A first circuit electrically connecting a positive electrode side of a load and the catalyst electrode, and electrically connecting a negative electrode side of the load and the semiconductor electrode;
A second circuit for electrically connecting a positive electrode side of a DC power source and the output recovery electrode, and connecting a negative electrode side of the DC power source and the semiconductor electrode;
A power generator comprising: a switch for selectively switching one of the first circuit and the second circuit to a closed state.   A method of recovering the output of a dye-sensitized solar cell when the dye-sensitized solar cell is deteriorated, wherein a voltage is applied so that a current flows in a direction opposite to that during power generation during non-power generation. Output recovery method.   8. A method for recovering the output of a dye-sensitized solar cell according to claim 1 when the dye-sensitized solar cell is deteriorated, wherein a current flows from the semiconductor electrode toward the output recovery electrode during non-power generation. A method for recovering the output of a dye-sensitized solar cell, wherein a voltage is applied as described above. The output of the dye-sensitized solar cell according to claim 10, wherein the semiconductor electrode area 1 mA / cm ² or more 200 mA / cm ² or less of current to is characterized in applying a voltage to flow below 100 seconds Recovery method.

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