JP5096064B2 - Dye-sensitized solar cell module - Google Patents

Description

  The present invention relates to a dye-sensitized solar cell module.

  Solar cells that can convert sunlight into electric power are attracting attention as an energy source to replace fossil fuels. Currently, solar cells that have been partially put into practical use include solar cells using crystalline silicon substrates and amorphous thin-film silicon solar cells.

  As a new type of solar cell, Patent Document 1 discloses a dye-sensitized solar cell to which photoinduced electron transfer of a metal complex is applied. This will be described with reference to FIG. This dye-sensitized solar cell is surrounded by conductive films (electrodes) 102 and 106 formed on two glass substrates 100 and 101, respectively, and sealing layers 103 and 103 formed therebetween. In the region, a photoelectric conversion layer 104 that is a metal oxide semiconductor layer on which a dye is adsorbed, a carrier transport layer (electrolytic solution) 107, and a catalyst layer 105 are stacked. In this dye-sensitized solar cell, when light is irradiated, electrons are generated in the photoelectric conversion layer 104, and the generated electrons pass through the conductive film 102 on the light-receiving surface side and the other conductive film 106 through the external electric circuit. It moves to the catalyst layer 105 and is further carried back to the photoelectric conversion layer 104 by ions in the carrier transport layer 107. Electric energy is taken out by repeating such movement of electrons.

Non-Patent Document 1 discloses a dye-sensitized solar cell module, and the Z-type module has a structure as shown in FIG. Between a glass substrate 110 on which a transparent conductive film (electrode) 112 is patterned and formed in a strip shape, and a glass substrate 111 on which a transparent conductive film (electrode) 116 and a catalyst layer 115 are sequentially patterned in a strip shape, a plurality of A photoelectric conversion element is formed, and a connection conductive layer 118 sandwiched between a pair of insulating layers 113 and 113 is formed between adjacent photoelectric conversion elements. The connection conductive layer 118 is connected to upper and lower transparent conductive films 112 and 116. Are electrically connected. The photoelectric conversion element is formed by sequentially laminating a photoelectric conversion layer 114, a carrier transport layer 117, and a catalyst layer 115 from the lower transparent conductive film 112 side.
Japanese Patent No. 2664194 Edited by Shuji Hayase and Akira Fujishima, “Dye-sensitized solar cell development technology”, Technical Education Publishing, June 6, 2003, p. 208

  In general, in a dye-sensitized solar cell, it is preferably fired at a temperature of 450 to 500 ° C. in the process of forming a porous semiconductor layer on a support provided with a transparent conductive film. For this reason, the problem that a support body warps arises. That is, the distance between the substrates increases toward the end of the support. For this reason, the spread of the distance between the substrates increases the thickness of the carrier transport layer and increases the resistance, resulting in a poor fill factor (fill factor FF). Therefore, there arises a problem that the characteristics of the single cells in the module vary due to the difference in the distance between the substrates due to the warpage.

  In order to solve the above problems, the present invention provides a dye-sensitized solar cell module that exhibits high performance by suppressing variations in the characteristics of single cells in the dye-sensitized solar cell module.

  The dye-sensitized solar cell module of the present invention includes a conductive support having a transparent conductive film and a grid on a support, a porous photoelectric conversion layer in which a dye is adsorbed on a porous semiconductor layer, and a carrier transport layer. And a dye-sensitized solar cell module in which a plurality of photoelectric conversion elements including a counter electrode are connected, wherein the photoelectric conversion elements are connected in series, and the unit per unit area of the dye-sensitized solar cell module The area of the grid is relatively wide from the center to the end of the module.

  In the dye-sensitized solar cell module according to the present invention, the grid area per unit area is relatively increased from the center of the modules connected in series toward the end portion, thereby varying the characteristics of the single cell. It is possible to provide a dye-sensitized solar cell module that suppresses and improves the module characteristics. That is, by providing a grid, the electrical resistance is reduced, and in addition, the area of the grid per unit area is relatively increased from the center to the end of the module, thereby warping the end of the support. However, the dispersion | variation in the characteristic of a single cell is suppressed, As a result, the dye-sensitized solar cell module which improved the characteristic of the module can be provided.

  In the present invention, a conductive support provided with a transparent conductive film and a grid on a support, a porous photoelectric conversion layer provided on the conductive support and having a porous semiconductor layer adsorbed with a dye, a carrier A plurality of dye-sensitized photoelectric conversion elements including a transport layer and a counter electrode are connected in series. In order to connect in series, for example, a conductive connection layer is provided between the dye-sensitized photoelectric conversion elements, and the conductive connection layer is electrically connected to a conductive support and an adjacent counter electrode. To do.

  And the area of the said grid per unit area of the said solar cell module is made relatively wide toward the edge part from the center part of a module. As a means for relatively widening, for example, the area of the grid per unit area of the solar cell module is relatively widened from the center of the module toward the end, or the line width of the grid Is substantially the same at the center and end of the module, and increases the number of grids from the center to the end of the module.

  In the present invention, the area of the grid per photoelectric conversion element of the module may be relatively increased from the photoelectric conversion element at the center of the module toward the photoelectric conversion element at the end in the serial connection direction. .

  In the present invention, the number of grids may be increased from the photoelectric conversion element at the center of the module toward the photoelectric conversion element at the end in the serial connection direction.

  In the present invention, the area of the porous photoelectric conversion layer may be increased from the center to the end of the module.

  In the present invention, the width of the porous photoelectric conversion layer may be increased from the photoelectric conversion element at the center of the module toward the photoelectric conversion element at the end in the series connection direction.

  Moreover, it is preferable that the said grid is a comb type.

  The dye-sensitized solar cell module of the present invention is a dye-sensitized solar cell module composed of a plurality of dye-sensitized solar cells connected in series in a plane between opposing substrates. Hereinafter, a preferred embodiment of the present invention will be described. In addition, the following description is only an example and implementation with a various form is possible within the scope of the present invention.

  1A is a plan view of an embodiment of the dye-sensitized solar cell module 20 of the present invention, FIG. 1B is a cross-sectional view taken along the line II of FIG. 1A, and FIG. 1C is a cross-sectional view taken along the line II-II of FIG. ing.

  As shown in FIG. 1A, when viewed from the plane of the dye-sensitized solar cell module 20, grids 21a to 21c 'are connected to the conductive connection layers 22 and 22a to 22c' vertically in one direction. The central opening 23 is an example in which no grid is formed. Light is irradiated to the openings 23a to 23c ', and the electrons generated here flow to the conductive connection layer through the grid and the transparent conductive film.

  In FIG. 1B, a transparent conductive film 12, a porous photoelectric conversion layer 14, a carrier transport layer 15, and a counter electrode 16 are sequentially stacked on a support 11, and the periphery is sealed with partition walls 18a and 18b. The grid 13 is formed on a predetermined portion of the transparent conductive film 12. The counter electrode 16 may be composed of a catalyst layer 16a and a conductive layer 16b. The porous photoelectric conversion layer 14 has a dye supported on a porous semiconductor layer. Although the transparent conductive film 12 and the grid 13 are shown in this order in FIG. 1B, they may be stacked in the reverse order. Reference numeral 17 denotes a substrate, and 19 denotes a connection layer.

  In FIG. 1B, electrons flow from α to β. Since the photoelectric conversion elements are connected in series, the extracted current is equivalent to the current of one cell, but the voltage is boosted by the number of cells connected in series. Therefore, high voltage and low current power can be obtained. Since high voltage and low current power is less likely to generate Joule heat, power loss can be reduced. This series connection-integration type is also referred to as Z-type (Non-Patent Document 1). The present invention may be the W type described in the above-mentioned document.

  As shown in FIG. 1C, the transparent conductive film 12, the porous photoelectric conversion layer 14, the carrier transport layer 15, and the counter electrode 16 are in communication with each other across the grid 13.

(Support)
If the support body 11 in this embodiment is a material generally used as a support body of a dye-sensitized solar cell, the material will not be specifically limited. For example, glass, polyethylene terephthalate (PET) film, polyethylene naphthalate (PEN) film, or the like can be used. Note that either one of the supports needs to have optical transparency. However, it is sufficient that it transmits light having a wavelength having an effective sensitivity to at least a sensitizing dye described later, and is not necessarily required to be transparent to light having all wavelengths.

(Transparent conductive film)
Examples of the transparent conductive film 12 in this embodiment include indium tin oxide (ITO, also referred to as indium-tin-oxide alloy), tin oxide (SnO ₂ ), and zinc oxide (ZnO). These films can be produced by using various known film forming techniques.

(grid)
As the grid 13 in the present embodiment, for example, a method of forming the transparent conductive film 12 after forming the grid 13 on the support 11 or a method of forming the grid 13 on the transparent conductive film 12 can be adopted. In addition, before forming the grid, a material having good wettability with the grid is formed in advance as a base layer, and then the grid can be formed.

  For example, as shown in FIG. 1A, the grid is arranged by connecting the grids 21 a to 21 c ′ perpendicularly in one direction from the conductive connection layers 22 and 22 a to 22 c ′ when viewed from the plane of the dye-sensitized solar cell module 20. Form. The central opening 23 is an example in which no grid is formed.

  FIG. 2 shows another grid arrangement example. When viewed from the plane of the dye-sensitized solar cell module 30, the grids 31 a to 31 d ′ are connected vertically from the conductive connection layers 32 a to 32 d ′ in one direction. A grid 21 a is also formed in the central opening 33. Light is irradiated to the openings 33a to 33d ', and electrons generated here flow to the conductive connection layer through the grid and the transparent conductive film.

  Various methods can be selected for forming the grid. For example, there are screen printing and vapor deposition. When screen printing is used, a grid suitable for the present invention can be formed by patterning the screen. Further, when the vapor deposition method is used, a grid suitable for the present invention can be formed by using a mask pattern.

  In general, in a dye-sensitized solar cell, a drying and firing process is involved in the process of forming a porous semiconductor layer on a support provided with a transparent conductive film. For example, the case where glass and tin oxide are used as a support and a transparent conductive film will be described. At this time, due to the difference in thermal expansion coefficient between the glass and tin oxide, the conductive support warps with the tin oxide surface protruding upward. For this reason, when producing a cell of a dye-sensitized solar cell, since the distance between the conductive support and the counter electrode is wider at the end than the center of the conductive support, the carrier transport layer filled in between Becomes larger. Further, in the case of a dye-sensitized solar cell module, since a large-area conductive support is used, the influence of the warpage on the carrier transport layer is further increased. At the end of the conductive support, the carrier transport layer is increased, so that the series resistance component in the dye-sensitized solar cell is increased, resulting in poor fill factor (FF) and poor photoelectric conversion characteristics. Become.

  Therefore, by increasing the area of the grid per unit area of the dye-sensitized solar cell module from the center of the dye-sensitized solar cell module toward the end of the module where the warpage of the conductive support increases. This series resistance component can be reduced. Since the resistance component of the conductive support itself can be reduced by increasing the area of the grid, it is possible to provide a dye-sensitized solar cell module with improved FF. More preferably, the area of the grid of photoelectric conversion elements may be increased from the photoelectric conversion element in the center of the module in the serial connection direction.

  In addition, when the support is in the form of a film such as a PET film or a PEN film, the warpage is caused from the center of the module toward the end due to the difference in thermal expansion coefficient between the film and the porous semiconductor layer and the flexibility. Occurs. In this case as well, by increasing the grid area per unit area of the dye-sensitized solar cell module from the center of the module connected in series toward the end, the series resistance component is the same as described above. Can be reduced.

  In addition, the grid shape is preferably a comb shape. By using the comb shape, current can be efficiently collected from the entire porous photoelectric conversion layer. Further, it is preferable to increase the number of combs from the center of the module toward the end. By increasing the number of combs, the area of the grid per unit area of the dye-sensitized solar cell module is increased, and the series resistance component can be reduced as described above. It is also preferable to increase the number of combs by making the line width of each grid substantially the same, from the center toward the end. More preferably, the number of grids of photoelectric conversion elements may be increased from the photoelectric conversion element at the center of the module in the serial connection direction.

  When the grid area of the photoelectric conversion element is increased from the photoelectric conversion element at the center of the module in the serial connection direction, the grid area that increases from the center of the module toward the edge is the photoelectric area that exists in the region near the center side. When the total area of the grid of the conversion elements (grid area ratio per cell) is 1, the total area of the grid of the photoelectric conversion elements existing in the outer region is preferably greater than 1 and 10 or less. More preferably, it is more than 1 and 6 or less.

  Further, the area ratio of the grid of the photoelectric conversion elements existing in the outer region is larger than 1 and preferably 10 or less when the area ratio of the grid of the photoelectric conversion elements existing in the area close to the center side is 1. The following is more preferable.

  Moreover, about the increase rate of the grid area ratio of an adjacent photoelectric conversion element, when the grid area ratio of the photoelectric conversion element of a center side is set to 1, the grid area ratio of an outer photoelectric conversion element is larger than 1, and is 5 or less. Is preferable, and 2 or less is more preferable.

  Moreover, about the increase rate of the grid area of an adjacent photoelectric conversion element, when the grid area of the photoelectric conversion element of a center side is set to 1, the grid area of an outer photoelectric conversion element is larger than 1, and 5 or less are preferable, 2 or less is more preferable.

  On the other hand, in a dye-sensitized solar cell module in which photoelectric conversion elements are connected in series, it is preferable that the performance of each dye-sensitized solar cell constituting the module, particularly the current value, is made uniform. Therefore, it is preferable to increase the area of the porous photoelectric conversion layer from the center to the end of the module, and the rate of area increase is preferably the same as that of the grid. By increasing the width of the porous photoelectric conversion layer 14 from the photoelectric conversion element at the center of the module toward the photoelectric conversion element at the end in the series connection direction, a dye-sensitized solar cell module with even better characteristics is produced. be able to.

This grid formation is not particularly restricted with respect to the connection methods in various dye-sensitized solar cell modules, and can be applied to known methods for connecting dye-sensitized solar cell modules. In the module of the present invention, the counter electrode 16 of the adjacent dye-sensitized solar cell and the transparent conductive film 12 and / or the grid 13 are electrically connected via the conductive connection layer 19 in order to make a series connection. The material of the transparent conductive film 12, the grid 13, or the counter electrode 16 of the adjacent dye-sensitized solar cell may be the same or different. The partition layer 18 is an electrical insulating layer. Further, in order to protect the conductive connection layer 19, the partition layer 18 may be provided on both sides of the conductive connection layer 19. A known inorganic material can be used for the partition layer 18. For example, glass frit or zirconium oxide can be used. The thickness only needs to be between the support and the counter electrode. As a material of the grid 13, a well-known thing can be used, for example, gold | metal | money, silver, platinum, chromium, nickel, titanium, or these 2 or more types of alloys can be used. As the transparent conductive film 12, indium tin oxide (ITO), tin oxide, zinc oxide, or the like can be used. Since the grid 13 may be corroded by iodine used for the carrier transport layer described below depending on the material and the forming method, a protective layer for protecting the grid may be used. Various known materials can be used as the material for the protective layer. For example, there are indium tin oxide, tin oxide, titanium oxide, SiO ₂ and the like. Further, the grid 13 may be formed on the support, and the transparent conductive film 12 may be formed thereon. In this case, the transparent conductive film 12 also serves as a protective layer. Moreover, when a protective layer is not used, it is preferable to use a material having no catalytic ability.

(Porous semiconductor layer)
Examples of the constituent material of the porous semiconductor layer forming the porous photoelectric conversion layer 14 include titanium oxide, zinc oxide, and tungsten oxide. Among these, titanium oxide is used from the viewpoint of stability and safety. Particularly preferably used.

  Examples of titanium oxide include anatase-type titanium oxide, rutile-type titanium oxide, amorphous titanium oxide, various titanium oxides such as metatitanic acid and orthotitanic acid, and titanium hydroxide and hydrous titanium oxide. These constituent materials can be used alone or in combination of two or more. Among these, anatase type titanium oxide is more preferable.

The method for forming the porous semiconductor layer is not particularly limited and a known method can be used. The main methods are as follows.
(1) A method in which a suspension containing semiconductor fine particles is applied on a carrier transport layer, followed by drying and / or firing.
(2) A chemical vapor deposition (CVD) method or a metal organic chemical vapor deposition (MOCVD) method using a predetermined source gas.
(3) Physical vapor deposition (PVD) method using a solid material, for example, vacuum vapor deposition method, sputtering method, ion plating method, ion plating method and the like.
(4) Sol-gel method and the like.

  As a method for forming the porous semiconductor layer, (1) is preferable because it is simple and has high performance. The formation method will be specifically described. A semiconductor fine particle as a material is added to a dispersing agent, a solvent and the like and dispersed to prepare a suspension, and the suspension is applied onto the carrier transport layer. Examples of the coating method include known methods such as a doctor blade method, a squeegee method, a spin coating method, a screen printing method, a spray method, and an ink jet method.

  Then, a porous semiconductor layer is obtained by drying and / or baking the coating film.

In drying and firing, it is necessary to appropriately set conditions such as temperature, time, and atmosphere depending on the type of substrate, electrodes, and semiconductor fine particles used. Firing can be performed, for example, in an air atmosphere or an inert gas atmosphere within a range of about 50 ° C. to 800 ° C. for about 10 seconds to 12 hours. This drying and baking can be performed once at a single temperature or twice or more by changing the temperature. The specific surface area of the porous semiconductor ^layer, 10 m 2 / g to 200 m approximately ² / g are preferred. The layer thickness is not particularly limited, but is preferably about 0.1 μm to 50 μm, and particularly preferably 1 μm to 35 μm.

  As the semiconductor fine particles, a single or compound semiconductor material having an average particle diameter in the range of 1 nm to 2000 nm can be used. Examples of suitable solvents for suspending the semiconductor fine particles include alcohols such as isopropyl alcohol, mixed solvents such as isopropyl alcohol / toluene, and water.

(Photosensitizing dye)
Examples of the dye that functions as a photosensitizer by being adsorbed on the porous photoelectric conversion layer 14 include those having absorption in various visible light regions and / or infrared light regions. Further, in order to firmly adsorb the dye to the porous photoelectric conversion layer 14, a carboxyl group, a carboxylic acid anhydride group, an alkoxy group, a hydroxyl group, a hydroxyalkyl group, a sulfonic acid group, an ester group, a mercapto group in the dye molecule. And those having an interlocking group such as a phosphonyl group (particularly those having a carbon atom of 1 to 3) are preferred. Among these, a carboxylic acid group and a carboxylic anhydride group are more preferable. The interlock group provides an electrical bond that facilitates electron transfer between the excited dye and the conduction band of the porous semiconductor layer.

  Examples of the dyes containing these interlock groups include ruthenium metal complex dyes, azo dyes, quinone dyes, quinone imine dyes, quinacridone dyes, squarylium dyes, cyanine dyes, merocyanine dyes, and triphenylmethane dyes. Xanthene dyes, porphyrin dyes, phthalocyanine dyes, berylene dyes, indigo dyes, naphthalocyanine dyes, and the like.

  Examples of the method for adsorbing the dye on the porous photoelectric conversion layer 14 include a method in which a porous semiconductor layer formed on a conductive support is immersed in a solution in which the dye is dissolved (dye adsorption solution). At that time, adsorption may be performed simply at room temperature, or heating by a reflux method may be performed in order to improve the adsorption rate.

  The solvent for dissolving the dye may be any solvent that dissolves the dye. Specifically, alcohols such as ethanol and methanol, ketones such as acetone and diethyl ketone, ethers such as diethyl ether and tetrahydrofuran, acetonitrile , Nitrile compounds such as benzonitrile, halogenated aliphatic hydrocarbons such as chloroform and methyl chloride, aliphatic hydrocarbons such as hexane and pentane, aromatic hydrocarbons such as benzene and toluene, esters such as ethyl acetate and methyl acetate And water. These solvents can be used alone or in admixture of two or more.

The concentration of the dye in the solution can be appropriately adjusted depending on the type of the dye and the solvent used, but is preferably as high as possible in order to improve the adsorption function, for example, 1 to 5 × 10 ⁻⁴ mol. / Liter or more. As an upper limit, although it changes with the kind of pigment | dye and solvent to be used, below a saturated solution is preferable.

(Carrier transport layer)
The carrier transport layer 15 is formed in contact with the porous photoelectric conversion layer 14 and has a function of transporting electrons to the dye in order to quickly reduce the oxidized form of the dye.

  The carrier transport layer 15 can be made of a material that can transport electrons, holes, or ions. For example, hole transport materials such as polyvinyl carbazole and triphenylamine; conductive polymers such as polythiophene and polypyrrole; ionic conductors such as electrolyte solution (electrolyte), molten salt, solid electrolyte, gel electrolyte; copper iodide, thiocyanic acid Examples include inorganic p-type semiconductors such as copper.

The ion conductor is preferably redox, and is not particularly limited as long as it is an electrolyte that can be generally used in batteries, solar cells, and the like. Specifically, LiI, NaI, KI, CsI, and an iodide such as iodine salt of CaI metal iodide, such as _2, and tetraalkylammonium iodide, pyridinium iodide, imidazolium iodide and quaternary ammonium compounds, Mixtures of iodine, bromides such as bromides of metal bromides (such as LiBr, NaBr, KBr, CsBr, CaBr ₂ ) and quaternary ammonium compounds such as tetraalkylammonium bromide, pyridinium bromide, mixtures of bromine, metal complexes ( Cobalt complexes, ferrocyanate-ferricyanate, ferrocene-ferricinium ions, etc.), sulfur compounds (polysulfide sodium, alkylthiol-alkyl disulfides, etc.), viologen dyes, hydroquinone-quinones, etc. That.

  Among these, dimethylpropylimidazolium iodide, LiI, pyridinium iodide, and a mixture of imidazolium iodide and iodine are preferable from the viewpoint of improving open circuit voltage.

  Moreover, you may add nitrogen-containing aromatic compounds, such as t-butylpyridine (TBP), as an additive conventionally used.

  As a solvent constituting the electrolyte solution (electrolyte solution), carbonate compounds such as ethylene carbonate and propylene carbonate; heterocyclic compounds such as 3-methyl-2-oxazolidinone; ether compounds such as dioxane and diethyl ether; ethylene glycol dialkyl ether; Ethers such as propylene glycol dialkyl ether, polyethylene glycol dialkyl ether, polypropylene glycol dialkyl ether, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, polyethylene glycol monoalkyl ether, polypropylene glycol monoalkyl ether; alcohols such as methanol and ethanol Ethylene glycol, propylene glycol, polyethylene group Polyhydric alcohols such as coal, polypropylene glycol, glycerin; nitrile compounds such as acetonitrile, glutarodinitrile, methoxyacetonitrile, propionitrile, benzonitrile; aprotic polar substances such as dimethyl sulfoxide, sulfolane, water, etc. .

  The electrolyte concentration in the electrolytic solution is preferably about 0.1 mol / liter to 5 mol / liter in order to increase the conductivity.

  As the solid electrolyte, a mixture of an electrolyte and an ion conductive polymer compound can be used. Examples of the ion conductive polymer compound include polar polymer compounds such as polyethers, polyesters, polyamines, polysulfides, and polyvinylidene fluoride.

  As a gel electrolyte, what was produced using electrolyte and a gelatinizer can be used. As the gelling agent, a polymer gelling agent is preferably used. Examples thereof include polymer gelling agents such as crosslinked polyacrylic resin derivatives, crosslinked polyacrylonitrile derivatives, polyalkylene oxide derivatives, silicone resins, and polymers having a nitrogen-containing heterocyclic quaternary compound salt structure in the side chain.

  As the molten salt gel electrolyte, a room temperature molten salt to which a gel electrolyte material is added can be used. As room temperature type molten salts, nitrogen-containing heterocyclic quaternary ammonium salt compounds such as pyridinium salts and imidazolium salts are preferably used.

  When forming a charge transport layer using a solid electrolyte, a gel electrolyte, or a molten salt gel electrolyte, the photoelectric conversion efficiency deteriorates unless the polymer electrolyte is sufficiently injected into the porous semiconductor layer. It is preferable to impregnate the monomer solution in (1) into the porous semiconductor layer and then polymerize it. Examples of the polymerization method include photopolymerization and thermal polymerization.

(Counter electrode)
Since the counter electrode 16 does not necessarily need to be transparent, it is not particularly limited as long as it is a conductor, but a metal is preferable from the viewpoint of conductivity. The counter electrode is preferably formed on the substrate 17. Examples of metals that are preferably used include Al, Cu, Zn, Au, Ag, Ti, W, Ni, and Pt. From the viewpoint of corrosion resistance, metals such as Pt, Ti, and W, and conductive metal oxides such as ITO and SnO ₂ are more preferably used.
Moreover, when using metals other than Pt as a counter electrode, it is preferable to form a catalyst layer on the surface, and it is preferable to form a thin layer with Pt or carbon.

  The method of forming the counter electrode 16 is not limited, and a method of generally forming an electrode such as a CVD method, an electroless plating method, an electrodeposition method, a printing method, or a metal or alloy thin plate attached with an adhesive or a double-sided tape. Any known method may be used as long as it is. The counter electrode 16 may be composed of a catalyst layer 16a and a conductive layer 16b.

(Conductive connection layer)
It is preferable to provide a conductive connection layer 19 in the thickness direction between the dye-sensitized photoelectric conversion elements so that the transparent conductive film 12 and the adjacent counter electrode 16 are electrically connected. The conductive connection layer 19 is made of a conductive material. Preferably, any of gold, silver, platinum, chromium, nickel, titanium, or an alloy of two or more thereof, or a transparent conductive material can be used, and the same as the transparent conductive film 12, the grid 13, or the counter electrode 16. It may consist of materials. Moreover, the thickness should just have the thickness between an electroconductive support body and a counter electrode.

(Encapsulant)
The sealing material is preferably provided in order to prevent volatilization of the carrier transport layer and intrusion of water or the like into the battery. The sealing material also has a function of (1) absorbing a fallen object and stress (impact) acting on the support, and (2) absorbing a deflection acting on the support during long-term use.

  As a material constituting the sealing material, a silicone resin, an epoxy resin, a polyisobutylene resin, a glass frit and the like are preferable, and two or more of these can be used in two or more layers. A hot melt resin can also be used. When a nitrile solvent or a carbonate solvent is used as the solvent for the carrier transport layer, silicone resin, hot melt resin (for example, ionomer resin), polyisobutylene resin, and glass frit are particularly preferable.

  The sealant pattern can be formed by a dispenser when silicone resin, epoxy resin, or glass frit is used. When using a hot melt resin, it can be formed by making a patterned hole in a sheet-like hot melt resin.

  What is necessary is just to set the thickness of the layer direction of a sealing material according to the distance between an electroconductive support body-counter electrode, and the thickness of a module.

  With the above configuration, the dye-sensitized solar cell module of the present invention (hereinafter referred to as “solar cell module”) can be provided.

  Examples The present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

  In addition, the schematic sectional drawing of the solar cell of this invention and solar cell module which are used by the following description are all examples, and this invention is not limited by these figures.

Example 1
First, tin-coated glass plate oxide (Nippon Sheet Glass Co., Ltd., trade name: SnO ₂ film-coated glass, SnO ₂ film thickness: 500 nm: glass substrate shape: Vertical 7 cm, horizontal 7 cm, thickness 0.11 cm) with a laser scribing Using the apparatus, tin oxide was removed with a width of 0.5 mm next to the porous semiconductor layer according to the pattern of the porous semiconductor layer to be formed later. On top of that, the patterns of the grids 31a to 31d ′ as shown in FIG. From the end, the number of grids is 12 for the grid 31d, 8 for the grid 31c, 5 for the grid 31b, 3 for the grid 31a, 5 for the grid 31b ′, The number of the grid 31c ′ is 8 and the number of the grid 31d ′ is 12. On top of that, SnO ₂ was formed by a CVD apparatus using a similar mask pattern, and a protective layer (not shown) was produced. Thereafter, using a commercially available titanium oxide paste (manufactured by Solaronix, trade name: Ti-Nanoxide DS / P), the width of the porous semiconductor layer is 5.5 mm, 5.3 mm, 5.1 mm, by screen printing. A porous semiconductor layer having a length of 5.0 mm, 5.1 mm, 5.3 mm, 5.5 mm and a length of 50 mm is formed, and after preliminary drying at 20 ° C. for 20 minutes, an electric furnace (manufactured by Denken Corporation) And trade name “KDF-P70”) at 500 ° C. for 1 hour. The film thickness of the porous semiconductor layer after firing was 20 μm. Integrated area of the grid on the porous semiconductor layer, the part of the grid 31d is 32.7 mm ^2, portions of the grid 31c is 21.0 mm ^2, portions of the grid 31b is 12.8 mm ^2, 31a portions of 7.5 mm ² , grid 31b 'portion of 12.8 mm ^2, the grid 31c' portion of 21.0 mm ^2, portions of the grid 31d 'was 32.7 mm ^2.

  In the same manner as described above, a glass plate with tin oxide is laser scribed, and a platinum paste (trade name “Pt-catalyst T / SP”) having the same shape as the porous semiconductor layer is formed by screen printing. And counter electrode was formed by baking at 450 ° C. for 30 minutes. Thereafter, an electrolyte inlet (not shown) was opened.

Sensitizing dye N719 represented by the following formula (Chemical Formula 1) (manufactured by Solaronix, trade name “Ru535bisTBA”, ruthenium dye) is dissolved in ethanol to a concentration of 3 × 10 ⁻⁴ mol / liter to obtain a dye solution. Got. Next, the conductive support on which the titanium oxide film was formed as the porous semiconductor layer was immersed in a dye solution for 12 hours to adsorb the sensitizing dye to the porous semiconductor layer. Thereafter, the porous semiconductor layer was washed with ethanol and dried to obtain a porous photoelectric conversion layer.

（化学式中、ＴＢＡはテトラブチルアンモニウムである。）

(In the chemical formula, TBA is tetrabutylammonium.)

  Next, partition layers were formed on both ends of the porous photoelectric conversion layer. As the partition wall layer, a UV curable resin (manufactured by ThreeBond: product name 31x-088) was used, and the discharge amount was adjusted so that the width of the resin after bonding was 1 mm, and it was applied so as to have the shape of FIG. 1B. . Thereafter, a commercially available conductive paste (manufactured by Fujikura Kasei Co., Ltd., trade name “Dotite”) was poured into the gaps between the partition walls, and dried to form a connection layer. The conductive support and the counter electrode were bonded together as shown in FIGS. 1B-C, and the portion coated with the UV curable resin was bonded by UV irradiation.

  Next, an electrolyte solution for the carrier transport layer was prepared. Acetonitrile (manufactured by Aldrich Chemical Company) was charged with 0.1 mol / liter lithium iodide (Aldrich Chemical Company), 0.01 mol / liter iodine (Aldrich Chemical Company), 0.5 mol / liter. T-butylpyridine (TBP, manufactured by Aldrich Chemical Company) and dimethylpropylimidazole iodide (DMPII, manufactured by Shikoku Kasei Co., Ltd.) having a concentration of 0.6 mol / liter were dissolved to obtain an electrolytic solution used as a carrier transport layer. .

  The electrolyte solution was injected by a capillary effect to form a carrier transport layer. The peripheral part was sealed with an epoxy resin to obtain a dye-sensitized solar cell module.

Moreover, the obtained module was irradiated with light having an intensity of 1 kW / m ² (AM1.5 solar simulator), and short-circuit current density, open-circuit voltage, FF (curve factor), and photoelectric conversion efficiency were measured. The conditions and results are shown in Tables 1-2.

(Example 2)
In the first embodiment, the number of grids from the end is 8 for the grid 31d, 5 for the grid 31c, 3 for the grid 31b, 2 for the grid 31a, 2 for the grid 31b ′. 3 parts, 5 parts of the grid 31c ′, 8 parts of the grid 31d ′, and the width of the porous semiconductor layer is 5.4 mm, 5.2 mm, 5.1 mm, 5.0 mm, 5 mm, The module was manufactured in the same manner as in Example 1 with a thickness of 0.1 mm, 5.2 mm, and 5.4 mm. The porous grid area on the semiconductor layer, portions of the grid 31d is 21.4 mm ^2, portions of the grid 31c is 13.0 mm ^2, portions of the grid 31b is 7.7 mm ^2, 31a portions of 5.0 mm ^2, the grid 31b 'portion of 7.7 mm ^2, the grid 31c' portion of 13.0 mm ^2, portions of the grid 31d 'was 21.4 mm ^2. The obtained module was irradiated with light having an intensity of 1 kW / m ² (AM1.5 solar simulator), and short-circuit current density, open-circuit voltage, FF (curve factor), and photoelectric conversion efficiency were measured. The conditions and results are shown in Tables 1-2.

(Example 3)
In the first embodiment, the number of grids from the end is 4 for the grid 31d, 3 for the grid 31c, 2 for the grid 31b, 1 for the grid 31a, and the grid 31b ′. , Two grids 31c ′, and four grids 31d ′, and the width of the porous semiconductor layer is 5.2 mm, 5.1 mm, 5.1 mm, 5.0 mm, 5 mm, The module was manufactured in the same manner as in Example 1 with a thickness of 0.1 mm, 5.1 mm, and 5.2 mm. The porous grid area on the semiconductor layer, portions of the grid 31d is 10.3 mm ^2, portions of the grid 31c is 7.7 mm ^2, portions of the grid 31b is 5.1 mm ^2, 31a portions of 2.5 mm ^2, the grid 31b 'portion of 5.1 mm ^2, the grid 31c' portion of 7.7 mm ^2, portions of the grid 31d 'was 10.3 mm ^2. The obtained module was irradiated with light having an intensity of 1 kW / m ² (AM1.5 solar simulator), and short-circuit current density, open-circuit voltage, FF (curve factor), and photoelectric conversion efficiency were measured. The conditions and results are shown in Tables 1-2.

Example 4
In the first embodiment, the number of grids from the end is 15 for the grid 31d, 12 for the grid 31c, 6 for the grid 31b, 3 for the grid 31a, 3 for the grid 31b ′. 6 parts, 12 parts of the grid 31c ′, 15 parts of the grid 31d ′, and the width of the porous semiconductor layer is 5.7 mm, 5.6 mm, 5.2 mm, 5.0 mm, 5 mm, The module was manufactured in the same manner as in Example 1 with a thickness of 0.2 mm, 5.6 mm, and 5.7 mm. The porous grid area on the semiconductor layer, portions of the grid 31d is 42.8 mm ^2, portions of the grid 31c is 33.3 mm ^2, portions of the grid 31b is 15.6 mm ^2, 31a portions of 7.5 mm ^2, the grid 31b 'portion of 15.6 mm ^2, the grid 31c' portion of 33.3 mm ^2, portions of the grid 31d 'was 42.8 mm ^2. The obtained module was irradiated with light having an intensity of 1 kW / m ² (AM1.5 solar simulator), and short-circuit current density, open-circuit voltage, FF (curve factor), and photoelectric conversion efficiency were measured. The conditions and results are shown in Tables 1-2.

(Example 5)
In the first embodiment, the number of grids from the end is 20 for the grid 31d, 15 for the grid 31c, 10 for the grid 31b, 5 for the grid 31a, and 5 for the grid 31b ′. 10 parts, 15 grids 31c ′, 20 grids 31d ′, and the width of the porous semiconductor layer is 6.0 mm, 5.6 mm, 5.3 mm, 5.0 mm, 5 mm, The module was manufactured in the same manner as in Example 1 with a thickness of 0.3 mm, 5.6 mm, and 6.0 mm. The porous grid area on the semiconductor layer, portions of the grid 31d is 59.5 mm ^2, portions of the grid 31c is 42.0 mm ^2, portions of the grid 31b is 26.5 mm ^2, 31a portion of 12.5 mm ^2, the grid 31b 'portion of 26.5 mm ^2, the grid 31c' portion of 42.0 mm ^2, portions of the grid 31d 'was 59.5 mm ^2. The obtained module was irradiated with light having an intensity of 1 kW / m ² (AM1.5 solar simulator), and short-circuit current density, open-circuit voltage, FF (curve factor), and photoelectric conversion efficiency were measured. The conditions and results are shown in Tables 1-2.

(Example 6)
In the first embodiment, the number of grids from the end is 14 for the grid 31d, 10 for the grid 31c, 7 for the grid 31b, 5 for the grid 31a, 5 for the grid 31b ′. 7 portions, 10 grid 31c ′ portions and 14 grid 31d ′ portions, and the width of the porous semiconductor layer is 5.5 mm, 5.3 mm, 5.1 mm, 5.0 mm, 5 mm, The module was manufactured in the same manner as in Example 1 with a thickness of 0.1 mm, 5.3 mm, and 5.6 mm. The porous grid area on the semiconductor layer, portions of the grid 31d is 38.5 mm ^2, portions of the grid 31c is 26.5 mm ^2, portions of the grid 31b is 17.9 mm ^2, 31a portion of 12.5 mm ^2, the grid 31b 'portion of 17.9 mm ^2, the grid 31c' portion of 26.5 mm ^2, portions of the grid 31d 'was 38.5 mm ^2. The obtained module was irradiated with light having an intensity of 1 kW / m ² (AM1.5 solar simulator), and short-circuit current density, open-circuit voltage, FF (curve factor), and photoelectric conversion efficiency were measured. The conditions and results are shown in Tables 1-2.

(Comparative Example 1)
A dye-sensitized solar cell module was produced in the same manner as in Example 1 except that the grid was not formed, and the obtained module was irradiated with light having an intensity of 1 kW / m ² (AM1.5 solar simulator). Then, short circuit current density, open circuit voltage, FF (fill factor) and photoelectric conversion efficiency were measured. The results are shown in Table 2.

(Comparative Example 2)
In Example 1, the grid area on the porous semiconductor layer, all except for the same area and 7.5 mm ^2, was produced in the same manner as in Example 1, the photoelectric conversion efficiency was measured. The results are shown in Table 2.

(Remarks)
* 1 The number increases from the center cell to the edge cell.
* 2 The area increases from the center cell to the edge cell.
* 3 Shows how many times the grid area of cells b, c and d is increased when the area of cell a is 1.
* 4 Indicates the grid area increase rate for the adjacent cell.
* 5 Indicates that the area of the porous semiconductor layer is increased.
* 6 Indicates that the area of the porous semiconductor layer is increased by the grid area.
* 7 Indicates that the grid area per unit area increases from the center toward the edge. Grid area / Porous semiconductor layer area * 8 Indicates the rate of increase of the grid area ratio to the adjacent cell.

  From the above results, when a grid is introduced, the fill factor (FF) is improved, and the conversion efficiency is improved by increasing the area from the center to the end of the dye-sensitized solar cell module. You can see that It has been confirmed that the present invention can provide a dye-sensitized solar cell module with improved module characteristics.

1A is a plan view of a dye-sensitized solar cell module according to an embodiment of the present invention, FIG. 1B is a cross-sectional view taken along the line II of FIG. 1A, and FIG. 1C is a cross-sectional view taken along the line II-II of FIG. FIG. 2 is a plan view of a solar cell module according to another embodiment of the present invention. FIG. 3 is a cross-sectional view of a conventional solar cell module. FIG. 4 is a cross-sectional view of another conventional solar cell module.

Explanation of symbols

11 Support (substrate)
12 Transparent conductive film 13, 21a-21c ', 31a-31d' Grid 14 Porous photoelectric conversion layer 15 Carrier transport layer 16, 16a, 16b Counter electrode 17 Substrate 18a, 18b Partition 19 Conductive connection layer 20, 30 Dye-sensitized type Solar cell module 22, 22a-22c ', 32a-32d' Conductive connection layer 23, 33, 23a-23c ', 33a-33d' Opening

Claims (6)

A plurality of photoelectric conversion elements including a conductive support having a transparent conductive film and a grid on a support, a porous photoelectric conversion layer in which a dye is adsorbed on a porous semiconductor layer, a carrier transport layer, and a counter electrode. A connected dye-sensitized solar cell module,
The photoelectric conversion elements are connected in series,
The dye-sensitized solar cell module, wherein an area of the grid per unit area of the dye-sensitized solar cell module is relatively widened from a center portion to an end portion of the module.   The area of the grid per photoelectric conversion element of the dye-sensitized solar cell module is relatively widened from the photoelectric conversion element at the center of the module toward the photoelectric conversion element at the end in the series connection direction. 2. The dye-sensitized solar cell module according to 1.   3. The dye sensitization according to claim 1, wherein a line width of the grid is substantially the same at a center portion and an end portion of the module, and the number of the grids is increased from the center of the module toward the end portion. Type solar cell module.   The dye-sensitized solar cell module according to any one of claims 1 to 3, wherein an area of the porous photoelectric conversion layer is further increased from a center of the module toward an end thereof.   The dye-sensitized solar cell module according to any one of claims 1 to 4, wherein the grid is comb-shaped.   A conductive connection layer is provided in the thickness direction between the dye-sensitized photoelectric conversion elements, and the conductive connection layer is electrically connected to a conductive support and an adjacent counter electrode. The dye-sensitized solar cell module according to any one of the above.

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