JP2007018809A - Dye-sensitized solar cell module and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dye-sensitized solar cell module capable of restraining cost and weight. <P>SOLUTION: This dye-sensitized solar cell module is provided, on a substrate 11, with first photoelectric conversion elements 1a and second photoelectric conversion elements 1b; the first photoelectric conversion element is composed by stacking a first conductive layer 12a, a porous semiconductor layer 13a with a dye adsorbed thereto, a porous insulation layer 14a, a catalyst layer 15a and a second conductive layer 17a in that order from the substrate and by impregnating an electrolyte into the porous semiconductor layer and the porous insulation layer; the second photoelectric conversion element 1b is composed by stacking a third conductive layer 12b, a catalyst layer 15b, a porous insulation layer 14, a porous semiconductor layer 13b with a dye adsorbed thereto and a fourth conductive layer 17b in that order from the substrate; and the porous semiconductor layers and the second photoelectric conversion elements are alternately arranged and serially connected. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a dye-sensitized solar cell module and a method for manufacturing the same.

  Solar cells that can convert sunlight into electric power are attracting attention as an energy source to replace fossil fuels. Currently, some solar cells that have begun to be put into practical use include solar cells using crystalline silicon substrates and thin-film silicon solar cells. However, the former has a problem that the manufacturing cost of the silicon substrate is high, and the latter needs to use various semiconductor gases and complicated apparatuses, and the manufacturing cost is still high. For this reason, efforts have been made to reduce the cost per power generation output by increasing the efficiency of photoelectric conversion in any of the solar cells, but they have not yet solved the above problem.

  As a new type of solar cell, for example, Patent Document 1 discloses a wet solar cell to which photoinduced electron transfer of a metal complex is applied. In this wet solar cell, a photoelectric conversion layer is formed by using a photoelectric conversion material and an electrolyte material between electrodes formed on two glass substrates. This photoelectric conversion material has an absorption spectrum in the visible light region by adsorbing a metal complex which is a photosensitizing dye. In this wet solar cell, electrons are generated when the photoelectric conversion layer is irradiated with light, and the electrons move to the counter electrode through an external electric circuit. The electrons that have moved to the counter electrode are carried by the ions in the electrolyte and return to the photoelectric conversion layer. Electric energy is taken out by repeating such movement of electrons.

  However, the basic structure of the dye-sensitized solar cell described in Patent Document 1 is one in which a dye-sensitized solar cell is built by injecting an electrolyte between two glass substrates. Therefore, even if trial production of a solar cell with a small area is possible, application to a solar cell with a large area such as 1 m square is difficult. This is because in such a solar battery, when the area of one solar battery cell is increased, the generated current increases in proportion to the area. However, the voltage drop in the in-plane direction of the transparent conductive film used for the electrode portion increases, and as a result, the internal series electric resistance as a solar cell increases. As a result, there is a problem that the fill factor (fill factor, FF) in the current-voltage characteristics at the time of photoelectric conversion, and further, the short-circuit current is lowered and the photoelectric conversion efficiency is lowered.

  In order to solve these problems, a unit cell adjacent to a first conductive layer of a rectangular unit cell used in an amorphous silicon solar cell module having a structure in which an amorphous silicon layer is sandwiched between first and second conductive layers An integrated structure in which the second conductive layer is contacted is conceivable.

  For example, Patent Document 2 discloses a dye-sensitized solar cell module in which a plurality of dye-sensitized solar cells are connected in series as shown in FIG. Specifically, each solar cell has a structure in which a titanium oxide layer, an insulating porous layer, and a counter electrode are sequentially laminated on a glass substrate on which a transparent conductive film (electrode) patterned in a strip shape is formed. Have. Moreover, both the solar cells are connected in series by disposing the conductive layer of one dye-sensitized solar cell so that the counter electrode is in contact with the adjacent dye-sensitized solar cell. In FIG. 3, 31 is a transparent substrate, 32 is a transparent conductive film, 33 is a porous titanium oxide layer, 34 is an intermediate porous insulating layer, 35 is a counter electrode, 36 is an insulating layer, and 37 is an electrically insulating liquid sealed. Represents the top cover.

  For example, Patent Document 3 discloses an integrated structure having a transparent conductive film 32, a porous semiconductor layer 33, an insulating layer 34, and a catalyst layer 35 on a translucent substrate 31. This technology prevents the catalyst layer from being mixed into the transparent conductive layer by specifying the particle size of the constituent particles of each layer. In the manufacturing process, the porous semiconductor layer / insulating layer / catalyst is formed on the translucent substrate. After the layer is formed, dye adsorption is performed.

  For example, Patent Document 4 discloses a dye-sensitized solar cell module having the structure shown in FIG. Specifically, on the glass substrate 40 having the transparent electrode 41 patterned in a strip shape, two films in which a titanium oxide layer 42 and a platinum layer 43 are alternately formed are produced, and each substrate is formed with a titanium oxide layer. And the platinum layer facing each other so that they face each other, and an insulating adhesive 44 such as a resin is placed between each overlapped titanium oxide / platinum layer pair, and facing each other with this insulating adhesive By attaching the glass substrate 40 to be bonded, a dye-sensitized solar cell module in which a plurality of solar cells are connected in series is manufactured (hereinafter referred to as a W-type module).

Japanese Patent No. 2664194 International Publication No. WO97 / 16838 Pamphlet Japanese Patent Laid-Open No. 2002-367686 International republished patent WO2002 / 052654 pamphlet

  In the W-type module of Patent Document 4, two glass substrates with a transparent conductive film 40 and 40 are used, and an element is formed between them to produce a solar cell module. Therefore, there are problems that the manufacturing cost of the solar cell module increases and the weight increases.

  The present invention has been made in view of the above-described problems, and provides a novel dye-sensitized solar cell module and a method for manufacturing the same that can reduce cost and weight while maintaining solar cell characteristics.

  Thus, according to the present invention, the first photoelectric conversion element and the second photoelectric conversion element are provided on one substrate, and the first photoelectric conversion element adsorbs the first conductive layer and the dye from the substrate. A porous semiconductor layer, a porous insulating layer, a catalyst layer, and a second conductive layer are laminated in this order, and the porous semiconductor layer and the porous insulating layer are impregnated with an electrolyte. The second photoelectric conversion element A third conductive layer, a catalyst layer, a porous insulating layer, a porous semiconductor layer on which a dye is adsorbed, and a fourth conductive layer are laminated in this order from the substrate, and the porous insulating layer and the porous semiconductor layer The dye-sensitized solar cell is formed by impregnating an electrolyte into the first and second photoelectric conversion elements, and the first photoelectric conversion element and the second photoelectric conversion element are connected in series. A module is provided.

Moreover, according to another viewpoint of this invention, it comprises the process of forming a 1st photoelectric conversion element and a 2nd photoelectric conversion element on a board | substrate, The said process is a 1st photoelectric conversion element formation area on the said board | substrate. The first conductive layer, the porous semiconductor layer, the porous insulating layer, the catalyst layer, and the second conductive layer are laminated in this order, and the third conductive layer and the catalyst layer are formed in the second photoelectric conversion element formation region on the substrate. A step of laminating a porous insulating layer, a porous semiconductor layer and a fourth conductive layer in this order to form a laminate, and impregnating the laminate with a dye solution to adsorb the dye to at least the porous semiconductor layer There is provided a method for producing a dye-sensitized solar cell module, comprising a step, a step of removing a dye from a porous insulating layer, and a step of impregnating a porous semiconductor layer and a porous insulating layer with an electrolyte.
Moreover, according to another viewpoint of this invention, it comprises the process of forming a 1st photoelectric conversion element and a 2nd photoelectric conversion element on a board | substrate, The said process is the 1st photoelectric conversion element formation area | region on the said board | substrate. The first conductive layer, the porous semiconductor layer, the porous insulating layer, the catalyst layer and the second conductive layer are laminated in this order, and the third conductive layer and the catalyst are formed in the second photoelectric conversion element formation region on the substrate. Laminating a layer, a porous insulating layer, a porous semiconductor layer, and a fourth conductive layer in this order to form a laminate, and impregnating the laminate with a dye solution to adsorb the dye to at least the porous semiconductor layer And a step of impregnating the porous semiconductor layer and the porous insulating layer with an electrolyte, and in the second photoelectric conversion element forming region in the step of forming a laminate, silicon atoms as a porous insulating layer forming material A sol solution or suspension containing Fabric was fired to a manufacturing method of the dye-sensitized solar cell modules forming the porous insulating layer.

According to the present invention, the first photoelectric conversion element and the second photoelectric conversion element are alternately arranged on one substrate, and another substrate is omitted from the surface opposite to the substrate. Thus, a dye-sensitized solar cell module having a novel structure with reduced cost and weight can be produced.
In addition, according to the present invention, a solar cell module having a structure in which the amount of dye adsorption of the porous insulating layer in the second photoelectric conversion element is small with respect to incident light having the light receiving surface on the substrate side can be manufactured. Incident light is less likely to be absorbed by the dye of the porous insulating layer, and the reduction of light reaching the porous semiconductor layer can be suppressed, and the generated current is larger than that with a large amount of dye adsorbed to the porous insulating layer. The value can be improved.

The dye-sensitized solar cell module of the present invention includes a first photoelectric conversion element and a second photoelectric conversion element on a single substrate, and the first photoelectric conversion element includes a first conductive layer, a dye from the substrate. The porous semiconductor layer, the porous insulating layer, the catalyst layer, and the second conductive layer adsorbed on the porous semiconductor layer are laminated in this order, and the porous semiconductor layer and the porous insulating layer are impregnated with an electrolyte. The two photoelectric conversion element includes a third conductive layer, a catalyst layer, a porous insulating layer, a porous semiconductor layer having a dye adsorbed thereon, and a fourth conductive layer stacked in this order from the substrate, and the porous insulating layer and It is configured by impregnating a porous semiconductor layer with an electrolyte, the first photoelectric conversion element and the second photoelectric conversion element are alternately arranged, and the first photoelectric conversion element and the second photoelectric conversion element are connected in series. It is characterized by.
Here, in the serial connection of the first photoelectric conversion element and the second photoelectric conversion element, the adjacent first conductive layer and third conductive layer are alternately electrically connected, insulated, and further electrically connected. The first photoelectric conversion element having the first conductive layer and the third conductive layer, the second conductive layer of the second photoelectric conversion element, and the fourth conductive layer are insulated, and the insulated first conductive layer and third conductive layer are insulated. The first photoelectric conversion element and the second conductive layer and the fourth conductive layer of the second photoelectric conversion element are electrically connected.
Here, in the present invention, the unit dye adsorption amount means the molar amount [mol / g] of the dye adsorbed per unit weight in the porous semiconductor layer or the porous insulating layer.

An example of the dye-sensitized solar cell module of the present invention (hereinafter sometimes referred to as a solar cell module) is shown in FIG.
The solar cell module of the present invention has a structure in which the first photoelectric conversion elements 1 a and the second photoelectric conversion elements 1 b are alternately arranged adjacent to each other on the substrate 11. The first photoelectric conversion element 1a includes a first conductive layer 12a, a porous semiconductor layer 13a having a dye adsorbed thereon, a porous insulating layer 14a, a catalyst layer 15a, and a second conductive layer 17a in this order from the substrate 11 side. In addition, the porous semiconductor layer 13a and the porous insulating layer 14a are impregnated with an electrolyte. In the second photoelectric conversion element 1b, the third conductive layer 12b, the catalyst layer 15b, the porous insulating layer 14b, the porous semiconductor layer 13b on which the dye is adsorbed, and the fourth conductive layer 17b are stacked in this order from the substrate 11 side. The porous insulating layer 14b and the porous semiconductor layer 13b are impregnated with an electrolyte. Thus, in the 1st photoelectric conversion element 1a and the 2nd photoelectric conversion element 1b, the lamination | stacking order of the film thickness direction of the porous semiconductor layer, the porous insulating layer, and the catalyst layer is reverse.

Moreover, the 1st photoelectric conversion element 1a and the 2nd photoelectric conversion element 1b are connected in series.
Further, an inter-element insulating layer 16 is formed between and around the first photoelectric conversion element 1a and the second photoelectric conversion element 1b.
The solar cell module having such a configuration includes a step of forming a first photoelectric conversion element and a second photoelectric conversion element on a substrate. This step includes the following first to fourth steps.

First step: First conductive layer 12a, porous semiconductor layer 13a, porous insulating layer 14a, catalyst layer 15a and second conductive layer 17a are laminated in this order on the first photoelectric conversion element formation region on substrate 11; In addition, the third conductive layer 12b, the catalyst layer 15b, the porous insulating layer 14b, the porous semiconductor layer 13b, and the fourth conductive layer 17b are stacked in this order on the second photoelectric conversion element formation region on the substrate 11 to form a stacked body. Form.
At this time, the porous insulating layer 14b in the second photoelectric conversion element formation region is preferably formed with a film thickness of 0.05 μm to 5 μm, and more preferably 0.01 μm to 2 μm. When the thickness of the porous insulating layer 14b in the second photoelectric conversion element formation region exceeds 5 μm, the amount of electrolyte impregnated in the voids of the porous insulating film increases and enters the second photoelectric conversion element 1b from the substrate 11. The amount of light absorbed by the light-absorbing substance (for example, iodine) in the electrolyte in the porous insulating layer increases, and the amount of light incident on the porous semiconductor layer of the next layer in contact with the porous insulating layer is Since it decreases, characteristics, such as a short circuit current density of a solar cell module, photoelectric conversion efficiency, fall.
Further, when the porous insulating layer 14b in the second photoelectric conversion element forming region is thinner than 0.05 μm, a portion where the catalyst layer 15b and the porous semiconductor layer 13b are in contact with each other is likely to be generated, and the porous semiconductor layer to the catalyst layer is easily formed. Since a reverse flow (reverse current) of electrons occurs, it is not preferable.

Moreover, in this 1st process, when using the material which a pigment | dye does not adsorb | suck easily as a formation material of the porous insulating layer 14b of a 2nd photoelectric conversion element formation area, it adsorb | sucks a pigment | dye well, and an acidic solution There is a case (b) where a porous insulating layer forming material is used together with a soluble material.
In the case of (a), silicon oxide is a representative material that is difficult to adsorb the dye. When forming the porous insulating layer, an organic silicon compound that generates silicon oxide by heating is used, or oxidation is performed. Silicon fine particles can be used.
In the case of (b), as the porous insulating layer forming material, fine particles such as titanium oxide, niobium oxide, zirconium oxide, aluminum oxide and barium titanate can be used singly or in combination. As materials soluble in acidic solutions, metal oxides such as magnesium oxide, zinc oxide, nickel oxide, and molybdenum oxide can be used alone or in combination of two or more. These materials form a porous insulating layer. By the heating at the time, a coating film is formed to cover the porous insulating layer, and a part of the dye at the time of dye adsorption in the next second step is adsorbed to the coating film.
After the first step and before the next second step, the inter-element insulating layer 16 serving as a partition is formed between and around each stacked body of the first and second photoelectric conversion element forming regions, and The conductive layer 17 that electrically connects them may be formed on the adjacent catalyst layer 15a and the porous semiconductor layer 13b.

  Second step: The laminate is impregnated with a dye solution to adsorb the dye to at least the porous semiconductor layers 13a and 13b. At this time, since the dye solution is also impregnated into the porous insulating layer 14b, in the case of (b), a part of the dye is adsorbed on the coating film.

Third step: In the case of (b) above, the dye is removed from the porous insulating layer.
The unit dye adsorption amount of the porous insulating layer and the porous semiconductor layer varies depending on the material of each layer. Therefore, before producing the solar cell module, a porous insulating layer sample and a porous semiconductor layer sample are produced using the same materials as the porous insulating layer and the porous semiconductor layer to be formed in the second photoelectric conversion element formation region, respectively. And it is preferable to adsorb | suck the pigment | dye used for a 2nd photoelectric conversion element to the said porous insulating layer sample and a porous semiconductor layer sample, and to measure each unit pigment | dye adsorption amount previously.

Fourth step: Porous semiconductor layers 13a and 13b and porous insulating layers 14a and 14b are impregnated with an electrolyte. At this time, it is preferable to use a redox electrolytic solution having fluidity and sufficiently infiltrate the inner center of each layer.
Hereinafter, each component of the solar cell module of the present invention and a method for forming the component will be described in the order of steps.

(substrate)
As the substrate 11, for example, a transparent glass substrate such as soda lime float glass, quartz glass, or crystal quartz glass, or a flexible film made of a heat-resistant translucent resin can be used. As a resin material for the flexible film, tetraacetylcellulose (TAC), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polycarbonate (PC), polyarylate (PA), polyetherimide (PEI), phenoxy resin Etc. These resins are advantageous in terms of cost and flexibility. It is necessary to form a translucent conductive layer described later on the surface of the translucent substrate made of these materials.
Also, any one of second and fourth conductive layers 17a and 17b, which will be described later, located on the side opposite to the substrate 11 only needs to be translucent, and the second and fourth conductive layers 17a and 17b are transparent. As long as it has optical property, the board | substrate 11 may be comprised with the material which does not have translucency. When the substrate 11 does not have translucency, specifically, a metal such as platinum, gold, silver, copper, aluminum, nickel, or titanium can be used as the material.

(First and third conductive layers)
When the substrate 11 has translucency, the first and third conductive layers 12a and 12b (conductive layer 12) also need to have translucency. Examples of the material of the light-transmitting conductive layer 12 include indium tin composite oxide (ITO), tin oxide doped with fluorine (FTO), and zinc oxide (ZnO). In particular, a translucent conductive substrate in which a translucent conductive layer made of FTO is laminated on a translucent substrate made of soda-lime float glass is suitable for the present invention. The method for forming the light-transmitting conductive layer on the light-transmitting substrate is not particularly limited, and examples thereof include a known sputtering method and spray method. The film thickness of the translucent conductive layer is preferably about 0.02 to 5 μm, and the lower the film resistance, the better, but it is preferably 40Ω / sq or less.
When the substrate 11 does not need translucency and a metal is used for the substrate 11, the first and third conductive layers may be omitted. Further, when ceramic or the like is used as the material of the substrate 11, the above-described conductive layer material having translucency may be used, or platinum, gold, silver, copper, aluminum, which does not have translucency, A metal material such as nickel or titanium may be used.

  In addition, a metal lead wire may be added to reduce the resistance of the first and third conductive layers. The material of the metal lead wire is preferably platinum, gold, silver, copper, aluminum, nickel, titanium or the like. The metal lead wire can be formed on the substrate by, for example, a known sputtering method or vapor deposition method, and the first and third conductive layers can be formed on the substrate including the metal lead wire. Alternatively, after forming the first and third conductive layers on the substrate, metal lead wires may be formed thereon. However, since the amount of incident light is reduced by providing a metal lead wire, the thickness of the metal lead wire is preferably about 0.1 to 4 mm.

(Porous semiconductor layer)
The porous semiconductor layers 13a and 13b are made of a semiconductor, and the form thereof can be various forms such as particles and films having a large number of micropores. Is preferred. The semiconductor constituting the porous semiconductor layer is not particularly limited as long as it is generally used for photoelectric conversion materials. For example, titanium oxide, iron oxide, niobium oxide, zirconium oxide, cerium oxide, tungsten oxide, nickel oxide, Examples thereof include strontium titanate, cadmium sulfide, lead sulfide, zinc sulfide, indium phosphide, copper-indium sulfide (CuInS ₂ ), CuAlO ₂ , SrCu ₂ O _{2 and the} like alone or in combination. Among these, titanium oxide, zinc oxide, tin oxide and niobium oxide are preferable, and titanium oxide is particularly preferable from the viewpoint of photoelectric conversion efficiency, stability and safety.

  In the present invention, the titanium oxide includes various narrowly defined titanium oxides such as anatase type titanium oxide, rutile type titanium oxide, amorphous titanium oxide, metatitanic acid, orthotitanic acid, titanium hydroxide, and hydrous titanium oxide. The two types of crystals, anatase type and rutile type, can take either form depending on the production method and thermal history, but the anatase type is common. In particular, regarding the sensitization of the organic dye of the present invention, those having a high content of anatase type are preferable, and the ratio is preferably 80% or more.

  The semiconductor constituting the porous semiconductor layer is preferably a polycrystalline sintered body made of fine particles from the viewpoints of stability, ease of crystal growth, production cost, and the like. Further, two or more kinds of semiconductors having the same or different particle sizes may be mixed and used.

  It is preferable that the ratio of the average particle diameter of the semiconductor particles having different particle sizes has a difference of 10 times or more. Semiconductor particles having a large average particle diameter can be used for the purpose of scattering incident light and increasing the light capture rate, and the average particle diameter is preferably 100 to 500 nm, and the semiconductor particles having a small average particle diameter have a dye adsorption point. It can be mixed with semiconductor particles having a large average particle size for the purpose of increasing the amount of adsorption and the average particle size is preferably 5 to 50 nm. In particular, when different semiconductors are mixed, it is effective to further increase the amount of dye adsorption if the semiconductor having a strong dye adsorption action is made to have a small particle size.

As the above-mentioned semiconductor particles, single or compound semiconductor particles having an appropriate average particle diameter among commercially available particles, for example, an average particle diameter of about 1 nm to 500 nm can be mentioned. Moreover, when using titanium oxide as a semiconductor particle, it can produce with the following method.
125 mL of titanium isopropoxide (manufactured by Kishida Chemical Co., Ltd.) was dropped into 750 mL of 0.1M aqueous nitric acid solution (manufactured by Kishida Chemical Co., Ltd.), hydrolyzed, and heated at 80 ° C. for 8 hours to prepare a sol solution. Do. Thereafter, particles are grown in a titanium autoclave at 230 ° C. for 11 hours, and ultrasonic dispersion is performed for 30 minutes to prepare a colloidal solution containing titanium oxide particles having an average primary particle size of 15 nm, and twice as much ethanol is added. Titanium oxide particles can be produced by centrifuging at 5000 rpm. In addition, the average particle diameter in this specification means the average particle diameter derived from the measurement result of the X-ray diffractometer and the Scherrer equation.

Solvents used for suspending these semiconductor particles to prepare a paste include glyme solvents such as ethylene glycol monomethyl ether, alcohol solvents such as isopropyl alcohol, mixed solvents such as isopropyl alcohol / toluene, water, and the like. Can be mentioned. Specifically, a paste can be produced by the steps shown below.
After washing the titanium oxide particles produced by the above-mentioned process, ethyl cellulose (manufactured by Kishida Chemical Co., Ltd.) and terpineol (manufactured by Kishida Chemical Co., Ltd.) dissolved in absolute ethanol are added, and the titanium oxide particles are stirred by stirring. Dispersed. Thereafter, ethanol is evaporated at 50 ° C. under a vacuum of 40 mbar to produce a titanium oxide paste. The final composition is adjusted so that the titanium oxide solid concentration is 20% by weight, ethyl cellulose is 10% by weight, and terpineol is 64% by weight.

<Method for forming porous semiconductor layer>
The method for forming the porous semiconductor layers 13a and 13b is not particularly limited, and examples thereof include a method in which a suspension containing semiconductor fine particles is applied, dried and / or baked. At this time, the first-stage application is on the transparent conductive layer 12a in the first photoelectric conversion element formation region, and the second-stage application is on a porous insulating layer 14b described later in the second photoelectric conversion element formation area. is there.
In the above method, first, semiconductor fine particles (for example, titanium oxide) are suspended in a suitable solvent. Examples of such a solvent include glyme solvents such as ethylene glycol monomethyl ether, alcohols such as isopropyl alcohol, alcohol mixed solvents such as isopropyl alcohol / toluene, water, and the like.

  In forming the porous semiconductor layer, the semiconductor fine particle suspension may be applied by a known method such as a doctor blade method, a squeegee method, a spin coating method, or a screen printing method. Thereafter, the coating film is dried and baked. The temperature, time, atmosphere, and the like necessary for drying and firing can be appropriately adjusted according to the type of substrate and semiconductor particles used, for example, about 50 to 800 ° C. in the air or in an inert gas atmosphere. In the range of about 10 seconds to 12 hours. Drying and firing may be performed only once at a single temperature, or may be performed twice or more by changing the temperature. When the porous semiconductor layer is formed of a plurality of layers, semiconductor fine particle suspensions having different average particle diameters may be prepared, and the coating, drying, and firing steps may be performed twice or more.

The thickness of the porous semiconductor layer (each layer in the case of a plurality of layers) is not particularly limited, and examples thereof include about 0.1 to 100 μm. In addition, from the viewpoint of dye adsorption, the porous semiconductor layer preferably has a large surface area, for example, about 10 to 200 m ² / g.
After forming the porous semiconductor layer, the porous semiconductor layer is treated with a treatment solution for the purpose of improving the electrical connection between the semiconductor particles, increasing the surface area of the porous semiconductor layer, and reducing the defect level on the semiconductor particles. May be. For example, when the porous semiconductor layer is a titanium oxide film, the semiconductor layer can be treated with an aqueous titanium tetrachloride solution.

  In addition, although the case where the semiconductor fine particle suspension was used was demonstrated in formation of the said porous semiconductor layer, it is also possible to form a porous semiconductor layer similarly to the above using a semiconductor fine particle paste. As the semiconductor fine particle paste, a commercially available titanium oxide paste (for example, Ti-nanoxide, D, T / SP, D / SP manufactured by Solaronics) may be used.

(Catalyst layer)
The catalyst layers 15a and 15b may be any material that activates the redox reaction of the electrolyte described later, and the material is selected from, for example, platinum, carbon (carbon black, ketjen black, carbon nanotube, fullerene). Of these, platinum is preferred. However, when the light receiving surface is the side opposite to the substrate of the solar cell module, the catalyst layer of the second photoelectric conversion element needs to be translucent, and thus is preferably a thin film. Although the preferred film thickness varies depending on the catalyst material, for example, when platinum is used, it is 0.5 to 1000 nm, more preferably 0.5 to 300 nm.

  As a formation method of a catalyst layer, when using platinum, it can form by well-known techniques, such as a PVC method, a vapor deposition method, sputtering method. When carbon is used, the catalyst layer can be formed by applying a paste in which carbon is dispersed in a solvent by a coating method such as a screen printing method. At this time, the first-stage coating is on the transparent conductive film in the second photoelectric conversion element formation region, and the second-stage coating is on a porous insulating layer described later in the first photoelectric conversion element formation region.

(Porous insulating layer of the first photoelectric conversion element)
Examples of the material used for the porous insulating layer 14a of the first photoelectric conversion element 1a include titanium oxide, niobium oxide, zirconium oxide, silicon oxide (silica glass, soda glass), aluminum oxide, and barium titanate. One or more of these materials can be selectively used, and these materials are preferably in the form of particles having an average particle size of 5 to 500 nm, preferably 10 to 300 nm. The titanium oxide is preferably a rutile type having a larger particle size than the anatase type.

<Method for Forming Porous Insulating Layer of First Photoelectric Conversion Element>
The above porous insulating layer forming fine particles are dispersed in a solvent, and a polymer compound is further mixed to prepare a mixed paste, and this mixed paste is applied onto the porous semiconductor layer 13 of the first photoelectric conversion element 1a. The porous insulating layer 14a can be formed by applying the coating film, drying the coating film, and baking it.

(Porous insulating layer of the second photoelectric conversion element)
Examples of the material used for the porous insulating layer 14b of the second photoelectric conversion element 1b include the same materials as the porous insulating layer 14a of the first photoelectric conversion element 1a. Further, when using, for example, titanium oxide, niobium oxide or the like when forming the porous insulating layer 14b of the second photoelectric conversion element 1b, in order to suppress the adsorption of the dye to these materials, magnesium oxide, zinc oxide, It is preferable to use fine particles of metal oxide such as nickel oxide and molybdenum oxide in combination. The average particle diameter of the metal oxide fine particles is 5 to 100 nm, preferably 10 to 50 nm. The film thickness of the porous insulating layer 14b of the second photoelectric conversion element 1b is 10 to 10000 nm, preferably 50 to 5000 nm.

<Method for Forming Porous Insulating Layer of Second Photoelectric Conversion Element>
[When forming a porous insulating layer made of a material difficult to adsorb dyes such as silicon oxide]
When the porous insulating layer is made of, for example, silicon oxide, it can be formed by the following sol-gel method. In this case, after stirring a sol solution in which an organic silicon compound (eg, tetramethoxysilane, tetraethoxysilane, etc.), ethanol, hydrochloric acid is dissolved in a solvent such as pure water, polyethylene glycol (molecular weight of about 2000) is used as a polymer compound. Add about 40% by weight and apply the mixture. After the coating film is dried, it is baked in a baking furnace whose temperature is adjusted to 500 ° C. At this time, the polymer compound is preferably added to the sol solution in order to increase the porosity (specific surface area) of the porous insulating layer. Examples of other polymer compounds include ethyl cellulose and nitrocellulose.
The porous insulating layer 14b can be formed by applying this sol solution onto the catalyst layer 15b of the second photoelectric conversion element 1b by a coating method, and drying and baking the coating film.
In addition to the sol-gel method, silicon oxide fine particles are dispersed in a solvent and a polymer compound is mixed to prepare a mixed paste. This mixed paste is applied onto the catalyst layer 15b of the second photoelectric conversion element 1b by a coating method. The porous insulating layer 14b can be formed by coating, drying and baking the coating film.

[When forming a porous insulating layer made of a material that easily adsorbs a dye]
When forming a porous insulating layer using fine particles for forming a porous insulating layer, such as titanium oxide and zirconium oxide, which are relatively easy to adsorb dyes, in order to suppress dye adsorption to the porous insulating layer in the subsequent dye adsorption step In addition, metal oxide fine particles such as magnesium oxide, zinc oxide, nickel oxide, and molybdenum oxide are used. The metal oxide fine particles and the porous insulating layer forming fine particles are dispersed in a solvent, and a polymer compound is further mixed to prepare a mixed paste. The mixed paste is applied to the catalyst layer 15b of the second photoelectric conversion element 1b. The coating film is applied by a coating method, and the coating film is dried and baked to form a porous insulating layer 14b formed by sintering the fine particles for forming the porous insulating layer, and the metal oxide covering the porous insulating layer 14b. A coating film can be formed (see Japanese Patent Application Laid-Open No. 2003-249275).

When the porous insulating layer 14b made of a material that easily adsorbs the dye is formed, in the subsequent dye adsorbing step, the substrate having the laminate is immersed in the dye solution to adsorb the dye to the porous semiconductor layer 14b. However, since the dye is also adsorbed to the coating film in the porous insulating layer 14b, the dye is removed from the porous insulating layer 14b by removing the coating film with an acidic solution. Hydrochloric acid, nitric acid or the like is used as the acidic solution, and its concentration is influenced by the dissolution time and the dye used, but is preferably about 0.2 to 2N (normality).
By forming the porous insulating layer 14b of the second photoelectric conversion element 1b in this way, the amount of dye adsorbed by the porous insulating layer 14b in the second photoelectric conversion element 1b with respect to incident light having the light receiving surface on the substrate side. Therefore, the light incident from the light receiving surface is difficult to be absorbed by the dye of the porous insulating layer 14b, and the decrease in the light reaching the porous semiconductor layer 13b can be suppressed, and the dye adsorbs to the porous insulating layer. The generated current value is improved as compared with a large amount. Therefore, the photoelectric conversion efficiency of the dye-sensitized solar cell module is improved.

(Insulation layer between elements)
As a material for forming the inter-element insulating layer 16, a commercially available material can be used. For example, ultraviolet curable material 31X-088 (manufactured by Three Bond Co., Ltd.), epoxy resin, high Milan (manufactured by DuPont Co., Ltd.) and the like can be mentioned.

(Second and fourth conductive layers)
The material of the second and fourth conductive layers 17a and 17b when formed on the non-light-receiving surface side is from the transparent conductive film 12 (first and third conductive films 12a and 12b) on the substrate serving as the light-receiving surface. However, a metal having a small specific resistance is preferable, and specifically, platinum, gold, silver, copper, aluminum, nickel, and titanium are preferable. In addition, the thickness of the conductive oxide film such as indium tin composite oxide (ITO), tin oxide (SnO ₂ ), tin oxide doped with fluorine (FTO), zinc oxide (ZnO), etc. is increased to increase sheet resistance. A material having a low value can also be used. Specifically, the sheet resistance of these metals and conductive oxides is preferably 10Ω / □ to 0.01Ω / □, and more preferably 2Ω / □ to 0.01Ω / □. The internal resistance of the battery is lowered and the FF is improved.
In addition, the second and fourth conductive layers when formed on the non-light-receiving surface side preferably have a low light transmittance from the viewpoint of light confinement of incident light. Specifically, the light transmittance is 50% or less, more preferably 30% or less.

The second and fourth conductive layers can be formed through the following procedure.
(1) In the region where the first photoelectric conversion element 1a is formed, the first conductive layer 12a, the porous semiconductor layer 13a, the porous insulating layer 14a, and the catalyst layer 15a are formed, and the second photoelectric conversion element 1b is formed. The third conductive layer 12b, the catalyst layer 15b, the porous insulating layer 14b, and the porous semiconductor layer 13b are formed in the region.
(2) Immerse the laminate in the dye solution. Thereafter, excess pigment is removed from the laminate with an alcohol solution or the like.
(3) The inter-element insulating layer 16 is formed between the first photoelectric conversion element 1a and the second photoelectric conversion element 1b.
(4) On the catalyst layer 15a of the first photoelectric conversion layer 1a, on the porous semiconductor layer 13b of the second photoelectric conversion element 1b, and on the inter-element insulating layer 16 using a known sputtering method, vapor deposition method, spray method or the like. The conductive layer 17 is formed so that the respective photoelectric conversion elements are electrically connected to each other. However, the fourth conductive layer 17b of the second photoelectric conversion element 1b connected in series with the second conductive layer 17a of one first photoelectric conversion element 1a is different from the second conductive layer 17a of the other first photoelectric conversion element 1a. Are not electrically connected in series.

(Dye)
In the present invention, as the dye, one or more of various photosensitizing dyes such as organic dyes and metal complex dyes having absorption in the visible light region and / or infrared light region may be selectively used. it can.

  Examples of organic dyes include azo dyes, quinone dyes, quinone imine dyes, quinacridone dyes, squarylium dyes, cyanine dyes, merocyanine dyes, triphenylmethane dyes, xanthene dyes, porphyrin dyes, and perylenes. And dyes such as indigo dyes and naphthalocyanine dyes. Organic dyes generally have a larger extinction coefficient than metal complex dyes in which molecules are coordinated to transition metals.

  Metal complex dyes include Cu, Ni, Fe, Co, V, Sn, Si, Ti, Ge, Cr, Zn, Ru, Mg, Al, Pb, Mn, In, Mo, Y, Zr, Nb, Sb, Metals such as La, W, Pt, Ta, Ir, Pd, Os, Ga, Tb, Eu, Rb, Bi, Se, As, Sc, Ag, Cd, Hf, Re, Au, Ac, Tc, Te, Rh In other words, phthalocyanine dyes, ruthenium dyes, and the like are preferably used. Among these, ruthenium-based metal complex dyes are more preferable, and in particular, ruthenium 535 dye of formula (1), ruthenium 535-bis TBA dye of formula (2), ruthenium 620-1H3TBA dye of formula (3) (manufactured by Solaronics) ) Is preferable.

  In the present invention, the dye has an interlocking group such as a carboxyl group, an alkoxy group, a hydroxyl group, a sulfonic acid group, an ester group, a mercapto group, and a phosphonyl group in order to strongly adsorb the dye to the porous semiconductor layer. Those are preferred. In general, a dye is fixed to a semiconductor via the interlock group, and has a function of providing an electrical coupling that facilitates the movement of electrons between the excited dye and the conduction band of the semiconductor.

<Method of adsorbing dye to porous semiconductor layer>
Examples of the method for adsorbing the dye to the porous semiconductor layer include a method of immersing the laminate on the substrate obtained through the above steps in the dye solution, and then removing the solvent by washing and drying. The solvent of the dye solution is not particularly limited as long as it dissolves the dye to be used. For example, an organic solvent such as alcohol, toluene, acetonitrile, tetrahydrofuran (THF), chloroform, dimethylformamide and the like can be used. These solvents are preferably purified. In order to improve the solubility of the dye, the solvent temperature may be increased, or two or more different solvents may be mixed. The dye concentration in the solvent can be appropriately adjusted according to the dye to be used, the type of solvent, the conditions for the dye adsorption step, etc., for example, preferably 1 × 10 ⁻⁵ mol / liter or more, and 1 × 10 ^{− 5} to 1 × 10 ⁻³ mol / liter is more preferable.

<Dye adsorption measurement experiment>
Here, titanium oxide is used as the material of the porous semiconductor layer of the second photoelectric conversion element, zirconium oxide, aluminum oxide, rutile titanium oxide and silica glass are used as the material of the porous insulating layer, and the porous semiconductor and the porous insulating layer are used. The amount of dye adsorbed was measured. The measurement experiment was performed as follows.

[Experiment 1]
Zirconium oxide fine particles having an average particle diameter of 30 nm, which is a material for forming a porous insulating layer, are dispersed in terpineol (manufactured by Kishida Chemical Co., Ltd.), mixed with ethyl cellulose (manufactured by Kishida Chemical Co., Ltd.), and finally solid zirconium oxide is obtained. The paste was adjusted so that the partial concentration was 16% by weight. Furthermore, magnesium oxide powder (manufactured by Kishida Chemical Co., Ltd.), which is a material for forming a coating film, is mixed in this paste at 10% by weight with respect to zirconium oxide, and after adjusting the pH to about 1 with hydrochloric acid and stirring for 10 minutes Then, ultrasonic dispersion is performed for 10 minutes to disperse magnesium oxide in zirconium oxide, and finally, a mixed paste for forming a porous insulating layer so that the total solid concentration of magnesium oxide and zirconium oxide becomes 18% by weight Adjusted.

_Two glass substrates with SnO ₂ film of 20 mm × 20 mm manufactured by Nippon Sheet Glass Co., Ltd. were prepared, the mixed paste was applied on one of the two substrates, the coating film was dried, and baked at 450 ° C. . As a result, a porous insulating layer (sample 1) having a film thickness of 1 μm was obtained.

In addition, a commercially available titanium oxide paste (manufactured by Solaronics, trade name Ti-Nanoxide D / SP, average particle size 13 nm) as a porous semiconductor layer on another glass substrate with SnO ₂ film was screen printed by a neuron precision Industrial use LS-150) was applied and baked at 500 ° C. for 60 minutes to obtain a titanium oxide film (sample 2) having a film thickness of about 14 μm as a porous semiconductor layer.

Next, the pigment | dye was made to adsorb | suck to the said sample 1 as follows.
First, ruthenium 535-bis TBA dye (manufactured by Solaronics) was used as a sensitizing dye, and an ethanol solution thereof (dye concentration: 4 × 10 ⁻⁴ mol / liter, manufactured by Aldrich) was prepared. Next, Sample 1 was immersed in this dye solution and allowed to stand for 20 hours under a temperature condition of 80 ° C. Thereafter, Sample 1 was washed with ethanol and dried.
In Sample 2, the dye was adsorbed in the same process as Sample 1.

  Thereafter, the sample 1 is immersed in 0.5N hydrochloric acid for about 10 minutes to dissolve the magnesium oxide adsorbed on the dye in hydrochloric acid, and the dye adsorbed on the magnesium oxide is removed together with the magnesium oxide. Let dry for minutes.

  In order to measure the dye adsorption amounts of Sample 1 and Sample 2 obtained through the above steps, they were immersed in 10 ml of 0.1N aqueous sodium hydroxide solution, and the dye was desorbed from Sample 1 and Sample 2. The obtained sodium hydroxide aqueous solution containing the leaving dye was put into a cell having a length of 1 cm in the light passing direction, and the absorbance at 530 nm was measured using a spectrophotometer UV-3150 (manufactured by Shimadzu Corporation). Further, four types of aqueous sodium hydroxide solutions having dye concentrations of 0.002 mM, 0.005 mM, 0.01 mM, and 0.02 mM were prepared, and calibration curves were obtained by measuring the respective absorbances. Then, the dye density | concentration of a desorption dye, and also unit dye adsorption amount were measured by comparing the absorbance of a desorption dye solution with the above four kinds of calibration curves. The results are shown in Table 1.

[Experiment 2]
The same process as Sample 1 of Experiment 1 was performed except that aluminum oxide (average particle size 40 nm) was used as the porous insulating layer forming material instead of the zirconium oxide used in Sample 1 of Experiment 1, and the solid A mixed paste having a partial concentration of 16% was prepared, the same process as Sample 1 of Experiment 1 was performed to prepare a laminate of Sample 3, dye adsorption was performed in the same manner as described above, and the unit dye adsorption amount was measured. The results are shown in Table 1.

[Experiment 3]
Except that a porous insulating layer forming material in which fine particles of zirconium oxide (average particle size 30 nm) and rutile-type titanium oxide (average particle size 300 nm) were mixed at a weight ratio (80:20) was used, The same process as Sample 1 is performed to prepare a mixed paste having a solid content concentration of 15%, the same process as Sample 1 of Experiment 1 is performed to prepare a laminate of Sample 4, and dye adsorption is performed in the same manner as described above. The unit dye adsorption amount was measured. The results are shown in Table 1.

[Experiment 4]
50 g of tetraethoxysilane, 74 g of ethanol, 47 g of pure water and 0.6 g of hydrochloric acid were mixed in a beaker and stirred at room temperature for 5 minutes, and then polyethylene glycol (molecular weight of about 2000) was added as a polymer compound to 40% by weight. And stirred to obtain a sol solution. A 20 mm × 20 mm glass substrate with SnO ₂ film manufactured by Nippon Sheet Glass Co., Ltd., on which a catalyst layer was formed, was immersed in this sol solution, pulled up, and then fired at 500 ° C. for 20 minutes to obtain a silica glass film. By repeating this process three times, a silica glass film having a film thickness of about 0.8 μm as a porous insulating layer was formed, and sample 5 was formed. The sample 5 was subjected to dye adsorption in the same manner as described above, and the unit dye adsorption amount was measured. The results are shown in Table 1.

From Table 1, a porous insulating layer (samples 1, 3, and 4) that was once coated with a magnesium oxide coating film, adsorbed to the dye, and then removed together with the dye, and a porous insulating layer made of silicon oxide (sample) 5) shows that the unit dye adsorption amount is suppressed to 0.1 times or less as compared with the porous semiconductor layer (sample 2) made of titanium oxide. Further, from the results of sample 5 in which the dye removal step is omitted unlike samples 1, 3, and 4, it can be seen that silicon oxide is a material that hardly adsorbs the dye, and the porosity for the second photoelectric conversion element It can be said that it is suitable for the material of the insulating film.
Another method for measuring the amount of adsorbed dye is to carefully scrape the porous semiconductor layer or porous insulating layer of each prepared sample from the substrate and remove the dye adsorbed on the porous semiconductor layer or porous insulating layer. It is possible to measure the amount of adsorption.

(Electrolyte: Redox species)
The electrolyte may be any of a liquid electrolyte, a solid electrolyte, a gel electrolyte, and a molten salt gel electrolyte.
The liquid electrolyte is not particularly limited as long as it is a liquid substance containing a redox species, and can be generally used in a battery, a solar battery, or the like. Specifically, those comprising a redox species and a solvent capable of dissolving this, those comprising a redox species and a molten salt capable of dissolving this, and those comprising a redox species, a solvent capable of dissolving this and a molten salt. Is mentioned.
The solid electrolyte is a conductive material that can transport electrons, holes, and ions, and can be used as an electrolyte of a solar cell and has no fluidity. Specifically, hole transport materials such as polycarbazole, electron transport materials such as tetranitrofluororenone, conductive polymers such as polyroll, polymer electrolytes obtained by solidifying liquid electrolytes with polymer compounds, copper iodide, thiocyanate Examples thereof include a p-type semiconductor such as copper acid, and an electrolyte obtained by solidifying a liquid electrolyte containing a molten salt with fine particles.
The gel electrolyte is usually composed of an electrolyte and a gelling agent. Examples of gelling agents include polymer gelation 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. An agent etc. are mentioned, and these can be used conveniently. The molten salt gel electrolyte is usually composed of a gel electrolyte material and a room temperature molten salt. Examples of the room temperature type molten salt include nitrogen-containing heterocyclic quaternary ammonium salt compounds such as pyridinium salts and imidazolium salts, and these can be suitably used.

Examples of the redox species used in the present invention include redox species such as I ⁻ / I ³⁻ , Br ²⁻ / Br ^{3 −} , Fe ²⁺ / Fe ³⁺ , and quinone / hydroquinone. It is done.
Specifically, a combination of metal iodide such as lithium iodide (LiI), sodium iodide (NaI), potassium iodide (KI), calcium iodide (CaI ₂ ) and iodine (I ₂ ), tetraethylammonium ion Tetraalkylammonium salts and iodine combinations such as dye (TEAI), tetrapropylammonium iodide (TPAI), tetrabutylammonium iodide (TBAI), tetrahexylammonium iodide (THAI), and lithium bromide (LiBr), A combination of metal bromide such as sodium bromide (NaBr), potassium bromide (KBr), calcium bromide (CaBr ₂ ) and bromine is preferable, and among these, a combination of LiI and I ₂ is particularly preferable.

  Examples of the solvent for the redox species include carbonate compounds such as propylene carbonate, nitrile compounds such as acetonitrile, alcohols such as ethanol, water, and aprotic polar substances. Among these, carbonate compounds and nitrile compounds are particularly preferable. Two or more of these solvents can be used in combination.

  As electrolyte additives, nitrogen-containing aromatic compounds such as t-butylpyridine (TBP), dimethylpropylimidazole iodide (DMPII), methylpropylimidazole iodide (MPII), ethylmethylimidazole iodide (EMII), ethyl Imidazole salts such as imidazole iodide (EII) and hexylmethylimidazole iodide (HMII) may be added.

The electrolyte concentration in the electrolyte is preferably in the range of 0.001 to 1.5 mol / liter, particularly preferably in the range of 0.01 to 0.7 mol / liter.
Next, the present invention will be described more specifically with reference to Production Examples, Examples and Comparative Examples, but the present invention is not limited to these Production Examples, Examples and Comparative Examples.

Example 1
<Preparation of porous semiconductor layer of first photoelectric conversion element and catalyst layer of second photoelectric conversion element>
As shown in FIG. 2, a 51 mm × 65 mm glass substrate with SnO ₂ film (substrate X) manufactured by Nippon Sheet Glass Co., Ltd. was used as a support on which a conductive layer was formed. In FIG. 2, 22 represents a porous semiconductor layer (titanium oxide film) formed in the first photoelectric conversion element formation region, and 23 represents a catalyst layer (platinum film) formed in the second photoelectric conversion element formation region. Represents. Hereinafter, a description will be given with reference to FIGS.

  First, the dimension A in FIG. 2 is 14 mm, the dimension B is 5 mm, the dimension C is 13 mm, the dimension D is 5 mm, the dimension E is 14 mm, the dimension F is 5 mm, the dimension G is 5 mm, the dimension H is 13 mm, and the dimension I is 5 mm. Then, a platinum film 23 having a thickness of about 5 nm was formed by sputtering as a catalyst layer in the second photoelectric conversion element formation region so that the dimension J was 13 mm, the dimension K was 5 mm, and the dimension L was 5 mm.

  Next, the first photoelectric conversion was performed using a commercially available titanium oxide paste (manufactured by Solaronics, trade name Ti-Nanoxide D / SP, average particle size 13 nm) using a screen printer (LS-150, manufactured by Neurong Seimitsu Kogyo). After applying to the element formation region and leveling at room temperature for 1 hour, the obtained coating film was pre-dried at 80 ° C. for 20 minutes to obtain a titanium oxide coating film 22 having a thickness of 14 μm.

Next, in FIG. 2, laser light (YAG laser, fundamental wavelength 1.06 μm) is applied to the SnO ₂ film as the conductive layer so that the dimension M is 12 mm, the dimension N is 20 mm, the dimension P is 20 mm, and the dimension Q is 12 mm. ) To evaporate the SnO ₂ film to form scribe lines 211 and 212.

<Preparation of porous insulating layer>
Zirconium oxide having an average particle size of 30 nm is dispersed in terpineol (manufactured by Kishida Chemical Co., Ltd.) and mixed with ethyl cellulose (manufactured by Kishida Chemical Co., Ltd.) so that the solid content concentration of zirconium oxide finally becomes 16% by weight. Paste A was prepared. Next, a zirconium oxide paste was prepared in the same manner as in Experiment 1 above, and magnesium oxide powder (manufactured by Kishida Chemical Co., Ltd.) having an average particle diameter of 20 nm was mixed with the paste in an amount of 10% by weight with respect to zirconium oxide. The pH is adjusted to about 1 with hydrochloric acid, stirred for 10 minutes, and then subjected to ultrasonic dispersion for 10 minutes to disperse the magnesium oxide fine particles in the paste. Finally, the solid content concentration of magnesium oxide and zirconium oxide is 18 Mixing paste B was adjusted so that it might become weight%.

  Paste A is applied onto the titanium oxide film 22 in the first photoelectric conversion element formation region that has been subjected to the preliminary drying using a screen printing machine (LS-150 manufactured by Neurong Seimitsu Kogyo), and further in the second photoelectric conversion element formation region. The mixed paste B was applied on the catalyst layer 23 so as to have the same shape as the titanium oxide film formed above, and the obtained coating film was preliminarily dried at 80 ° C. for 20 minutes, and each coated with paste B having a thickness of about 1 μm. A film was obtained.

<Preparation of porous semiconductor layer of second photoelectric conversion element and catalyst layer of first photoelectric conversion element>
A commercially available titanium oxide paste (manufactured by Solaronix, trade name Ti-Nanoxide D / SP, average particle size 13 nm) was screened on the catalyst layer 23 of FIG. After coating on the insulating layer formed and leveling at room temperature for 1 hour, the resulting coating film was pre-dried at 80 ° C. for 20 minutes and baked at 450 ° C. for 1 hour to obtain a film thickness of 14 μm. A titanium oxide coating film was obtained. Next, on the insulating layer formed on the titanium oxide film 22 in FIG. 2, a platinum film having a thickness of about 5 nm was formed as a catalyst layer by sputtering.
The laminate of the titanium oxide coating film, paste B coating film and platinum film thus obtained was baked at about 500 ° C. for 60 minutes in an oxygen atmosphere. As a result, a porous semiconductor layer made of a titanium oxide film and a porous insulating layer were formed.

<Dye adsorption>
Next, the dye was adsorbed to the laminate as follows.
First, ruthenium 535-bisTBA dye (manufactured by Solaronics) was used as a sensitizing dye, and an ethanol solution thereof (dye concentration: 4 × 10 ⁻⁴ mol / liter, produced by Aldrich) was prepared. Next, the laminate was immersed in this solution and allowed to stand for 20 hours under a temperature condition of 80 ° C. Thereafter, the laminate was washed with ethanol and dried. Thereby, a pigment | dye adsorb | sucks to each porous semiconductor layer and each porous insulating layer, and a pigment | dye adsorb | sucks to the magnesium oxide coating layer currently formed in the porous insulating layer in the 2nd photoelectric conversion element formation area.
In the first and second photoelectric conversion element formation regions, the unit dye adsorption amount of each porous semiconductor layer is 1.6 × 10 ⁻⁵ mol / g, and the unit dye adsorption amount of each porous insulating layer is 1.0 × 10 ⁻⁶ mol / g.

<Removal of magnesium oxide coating layer>
The layered product on which the dye was adsorbed was immersed in 0.5N hydrochloric acid for about 10 minutes. Thereby, the magnesium oxide coating layer in which the dye in the porous insulating layer in the second photoelectric conversion element formation region is adsorbed is dissolved in hydrochloric acid, and the dye is removed from the porous insulating layer together with magnesium oxide. Thereafter, the laminate was washed with water and dried at about 60 ° C. for about 20 minutes.

<Formation of inter-element insulating layer, second and fourth conductive layers>
In FIG. 2, an ultraviolet curable material 31X-088 (manufactured by Three Bond Co., Ltd.) is applied between and around each laminated body in the first and second photoelectric conversion element forming regions, and is applied using an ultraviolet irradiation lamp. The portion was irradiated with ultraviolet rays to form an inter-element insulating layer 16 serving as a partition as shown in FIG.
Further, in order to electrically connect the first photoelectric conversion element and the second photoelectric conversion element for each pair, as shown in FIG. 1, an electron beam vapor deposition device (manufactured by ANELVA) is used. A conductive layer 17 having a thickness of 1 μm was formed. The sheet resistance of the conductive layer after lamination was 3.63 × 10 ⁻⁵ Ω / □.

<Adjustment of electrolyte>
As a redox electrolyte, acetonitrile was used as the solvent, DMPII was 0.6 mol / liter, LiI was 0.1 mol / liter, TBP was 0.5 mol / liter, and I ₂ was 0.02 mol / liter. A dissolved electrolyte was prepared.

<Injection of electrolyte>
Using a PET film laminated with a heat-sealing sheet (trade name: Surlyn, manufactured by DuPont) as a top cover, the film is heat-sealed so as to cover the laminated body, and a capillary effect is applied to the laminated body from the sealing provided on the heat-sealing sheet. The dye-sensitized solar cell of Example 1 is injected by injecting the redox electrolyte solution, impregnating each porous semiconductor layer and each porous insulating layer with the electrolyte solution, and sealing the sealing by thermal fusion. A module was produced.
The obtained solar cell 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, fill factor, and photoelectric conversion efficiency were measured. The results are shown in Table 2.

(Example 2)
A dye-sensitized solar cell module was produced in the same manner as in Example 1 except that the porous insulating layer (before firing) was produced according to the following procedure. Only the steps different from those in Example 1 will be described below.
<Preparation of porous insulating layer>
Aluminum oxide fine particles having an average particle diameter of 40 nm are dispersed in terpineol (manufactured by Kishida Chemical Co., Ltd.) and mixed with ethyl cellulose (manufactured by Kishida Chemical Co., Ltd.), so that the solid content concentration of aluminum oxide finally becomes 14% by weight. Paste C was prepared. Next, an aluminum oxide paste was prepared in the same manner as in Experiment 2, and 11 wt% of magnesium oxide powder (manufactured by Kishida Chemical Co., Ltd.) having an average particle diameter of 20 nm was mixed with the paste in an amount of 11 wt% After adjusting the pH to about 1 with hydrochloric acid and stirring for 10 minutes, ultrasonic dispersion is performed for 10 minutes to disperse the magnesium oxide fine particles in the paste, and finally the total solid concentration of magnesium oxide and aluminum oxide is The mixed paste D was adjusted to 16% by weight.

A paste C is applied on the preliminarily dried titanium oxide film 22 using a screen printer (LS-150 manufactured by Neurong Seimitsu Kogyo), and the same shape as the titanium oxide film formed above on the catalyst layer 23. The mixed paste D was applied so that the resulting coating film was pre-dried at 80 ° C. for 20 minutes to obtain porous insulating layers each having a thickness of about 2 μm.
In the second photoelectric conversion element formation region, the unit dye adsorption amount of the porous semiconductor layer is 1.5 × 10 ⁻⁵ mol / g, and the unit dye adsorption amount of the porous insulating layer formed of the paste D is 1.0. × 10 ^-6 mol / g.
The obtained solar cell module of Example 2 was irradiated with light having an intensity of 1 kW / m ² (AM1.5 solar simulator), and short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency were measured. The results are shown in Table 2.

(Example 3)
A dye-sensitized solar cell module was produced in the same manner as in Example 1 except that the porous insulating layer (before firing) was produced according to the following procedure. However, the formation of the porous insulating layer of the second photoelectric conversion element was performed prior to the formation of the porous semiconductor layer of the first photoelectric conversion element. Only the steps different from those in Example 1 will be described below.

<Preparation of porous insulating layer>
250 g of tetraethoxysilane, 370 g of ethanol, 235 g of pure water, and 3 g of hydrochloric acid were mixed in a glass container containing a glass substrate having a size of 51 mm × 65 mm, stirred for 5 minutes at room temperature, and further added with polyethylene glycol (molecular weight of about 2000) for 40 minutes. It added so that it might become weight%, and it stirred and obtained the sol liquid. Masking is performed by applying a Kapton tape on the first photoelectric conversion element formation region (region 22) of the glass substrate X (see FIG. 2), and the glass substrate is immersed in a sol solution, pulled up, and then maintained at 500 ° C. The substrate was placed in a fired baking furnace and baked for 20 minutes to obtain a silica glass film. By repeating this process three times, an insulating layer made of silica glass having a thickness of about 1 μm was obtained on the catalyst layer in the second photoelectric conversion element formation region.
In the second photoelectric conversion element formation region, the unit dye adsorption amount of the porous semiconductor layer is 1.6 × 10 ⁻⁵ mol / g, and the unit dye adsorption amount of the porous insulating layer made of silica glass is 5.6 ×. 10 ⁻⁷ mol / g. The obtained solar cell module of Example 3 was irradiated with light having an intensity of 1 kW / m ² (AM1.5 solar simulator), and short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency were measured. The results are shown in Table 2.

Example 4
A dye-sensitized solar cell module was produced in the same manner as in Example 1 except that the porous insulating layer (before firing) was produced according to the following procedure. Only the steps different from those in Example 1 will be described below.

<Preparation of porous insulating layer>
Silicon oxide fine particles having an average particle size of 30 nm are dispersed in terpineol (manufactured by Kishida Chemical Co., Ltd.) and mixed with ethyl cellulose (manufactured by Kishida Chemical Co., Ltd.), so that the solid content concentration of aluminum oxide finally becomes 15% by weight. Paste E was prepared.
Paste E is applied onto the preliminarily dried titanium oxide film 22 using a screen printing machine (LS-150 manufactured by Neurong Seimitsu Kogyo), and the same shape as the titanium oxide film formed above on the catalyst layer 23. The mixed paste E was applied so that the obtained coating film was pre-dried at 80 ° C. for 20 minutes and then baked at 500 ° C. for 20 minutes to obtain insulating layers each having a thickness of about 2 μm.
In the second photoelectric conversion element formation region, the unit dye adsorption amount of the porous semiconductor layer is 1.6 × 10 ⁻⁵ mol / g, and the unit dye adsorption amount of the porous insulating layer formed of the paste E is 6.6. × 10 ^-7 mol / g. The obtained solar cell module of Example 4 was irradiated with light having an intensity of 1 kW / m ² (AM1.5 solar simulator), and short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency were measured. The results are shown in Table 2.

(Examples 5-7)
In preparation of the porous insulating layer (before baking) of a 2nd photoelectric conversion element formation area, the film thickness after baking is adjusted by adjusting the film thickness of the coating film by a screen printing method using the mixed paste B of Example 1. FIG. Is a dye-sensitized solar cell module in the same manner as in Example 1 except that a porous insulating layer made of zirconium oxide of 2 μm (Example 5), 3 μm (Example 6) and 4 μm (Example 7) is prepared. Was made.

The obtained solar cell modules of Examples 5 to 7 were irradiated with light having an intensity of 1 kW / m ² (AM1.5 solar simulator), and short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency were measured. . The results are shown in Table 2.

(Examples 8 and 9)
A dye-sensitized solar cell module was produced in the same manner as in Example 1 except that the thickness of the conductive layer 17 (see FIG. 1) was 500 nm and 300 nm. The sheet resistance of the conductive layer 17 was 65 mΩ / □ at a thickness of 500 nm and 1.317 Ω / □ at a thickness of 300 nm.
The obtained solar cell modules of Examples 8 and 9 were irradiated with light having an intensity of 1 kW / m ² (AM1.5 solar simulator), and short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency were measured. . The results are shown in Table 2.

(Comparative Example 1)
A dye-sensitized solar cell module was produced in the same manner as in Example 1 except that the porous insulating layer (before firing) was produced according to the following procedure. Only the steps different from those in Example 1 will be described below.

<Preparation of insulating layer>
The paste A used in Example 1 was applied onto the titanium oxide film 22 in the first photoelectric conversion element forming region that had been pre-dried by a screen printing machine (LS-150, manufactured by Neurong Seimitsu Kogyo), and further the second photoelectric conversion was performed. On the catalyst layer 23 in the element formation region, the paste A was applied so as to have the same shape as the titanium oxide film formed above, and the obtained coating film was pre-dried at 80 ° C. for 20 minutes and then baked at 500 ° C. for 60 minutes. Thus, an insulating layer having a thickness of about 1 μm was obtained.
In the second photoelectric conversion element formation region, the unit dye adsorption amount of the porous semiconductor layer is 1.4 × 10 ⁻⁵ mol / g, and the unit dye adsorption amount of the porous insulating layer is 2.0 × 10 ⁻⁶ mol. / G.
The obtained solar cell was irradiated with light having an intensity of 1 kW / m ² (AM1.5 solar simulator), and short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency were measured. The results are shown in Table 2.

(Comparative Example 2)
A dye-sensitized solar cell was produced in the same manner as in Example 2, except that the paste for forming the porous insulating layer in the second photoelectric conversion element formation region was subjected to the following procedure.
<Preparation of insulating layer forming paste>
Aluminum oxide fine particles having an average particle diameter of 30 nm, which is a porous insulating layer forming material, are dispersed in terpineol (manufactured by Kishida Chemical Co., Ltd.), mixed with ethyl cellulose (manufactured by Kishida Chemical Co., Ltd.), and finally solid aluminum oxide. The paste was adjusted so that the partial concentration was 17% by weight.
In the second photoelectric conversion element formation region, the unit dye adsorption amount of the porous semiconductor layer is 1.5 × 10 ⁻⁵ mol / g, and the unit dye adsorption amount of the porous insulating layer is 2.2 × 10 ⁻⁶ mol. / G.
The obtained solar cell was irradiated with light having an intensity of 1 kW / m ² (AM1.5 solar simulator), and short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency were measured. The results are shown in Table 2.

(Comparative Examples 3 and 4)
In preparation of the porous insulating layer (before baking) of 2nd photoelectric conversion element formation, the film thickness after baking is adjusted by adjusting the film thickness of the coating film by the screen printing method using the mixed paste B of Example 1. A dye-sensitized solar cell module was produced in the same manner as in Example 1 except that porous insulating layers made of zirconium oxide of 6 μm and 8 μm were produced.
The obtained solar cell modules of Comparative Examples 2 and 3 were irradiated with light having an intensity of 1 kW / m ² (AM1.5 solar simulator), and short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency were measured. . The results are shown in Table 2.

(Comparative Examples 5 and 6)
A dye-sensitized solar cell module was produced in the same manner as in Example 1 except that the thickness of the conductive layer 17 (see FIG. 1) was 100 nm and 50 nm. The sheet resistance of the conductive layer 17 was 26.45Ω / □ at a thickness of 100 nm and 56.00Ω / □ at a thickness of 50 nm.
The obtained solar cell modules of Comparative Examples 5 and 6 were irradiated with light having an intensity of 1 kW / m ² (AM1.5 solar simulator), and short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency were measured. . The results are shown in Table 2.

From the obtained result, it turns out that the solar cell module of Examples 1-8 has a short circuit current density and a fill factor (FF) higher than the solar cell module of Comparative Examples 1-6, and, as a result, photoelectric conversion efficiency is high. It was.
In particular, when Examples 1-4 and Comparative Examples 1 and 2 are compared, the dye adsorption amount of the porous insulating layer in the second photoelectric conversion element is 0.1 times or more the unit dye adsorption amount of the porous semiconductor. In Comparative Examples 1 and 2, it can be seen that the short-circuit current is reduced due to the filter effect of the pigment in the porous insulating layer.
Further, when Examples 1, 5 to 7 and Comparative Examples 3 and 4 are compared, Comparative Examples 2 and 3 in which the thickness of the porous insulating layer of the second photoelectric conversion element exceeds 5 μm have low photoelectric conversion efficiency. This is because the volume of the electrolyte is increased by increasing the volume of the porous insulating film, so that the light absorption of iodine in the electrolyte is increased and the light incident on the porous semiconductor layer is decreased. It is considered that the current density and the fill factor are reduced, and as a result, the photoelectric conversion efficiency is lowered.
Furthermore, when Examples 1, 8, and 9 are compared with Comparative Examples 4 and 5, when the sheet resistance of the conductive layers (second and fourth conductive layers) is 2Ω / □ or less, FF is improved and high conversion efficiency is achieved. Is obtained.

It is sectional drawing which shows schematic structure of the dye-sensitized solar cell module of this invention. It is a figure explaining the manufacturing method of the solar cell module of FIG. 1, Comprising: It is a schematic plan view which shows the film-forming state on a board | substrate. It is a schematic sectional drawing of the conventional dye-sensitized solar cell module. It is a schematic sectional drawing of another conventional dye-sensitized solar cell module.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a 1st photoelectric conversion element 1b 2nd photoelectric conversion element 11 Board | substrate 12 Conductive layer 12a 1st conductive layer 12b 3rd conductive layer 13a, 13b Porous semiconductor layers 14a, 14b Porous insulation layers 15a, 15b Catalyst layer 16 Inter-element insulation Layer 17 Conductive layer 17a Second conductive layer 17b Fourth conductive layer

Claims (13)

A first photoelectric conversion element and a second photoelectric conversion element are provided on a single substrate,
The first photoelectric conversion element includes a porous semiconductor layer in which a first conductive layer, a porous semiconductor layer having a dye adsorbed thereon, a porous insulating layer, a catalyst layer, and a second conductive layer are stacked in this order from the substrate. Layer and porous insulating layer impregnated with electrolyte,
The second photoelectric conversion element is formed by laminating a third conductive layer, a catalyst layer, a porous insulating layer, a porous semiconductor layer adsorbing a dye, and a fourth conductive layer in this order from the substrate, and porous insulating Layer and porous semiconductor layer impregnated with electrolyte,
The dye-sensitized solar cell module, wherein the first photoelectric conversion element and the second photoelectric conversion element are alternately arranged, and the first photoelectric conversion element and the second photoelectric conversion element are connected in series.   The dye-sensitized solar cell module according to claim 1, wherein the substrate, the first conductive layer, and the third conductive layer are translucent.   The dye-sensitized solar cell module according to claim 2, wherein the sheet resistance of the second conductive layer and the fourth conductive layer is lower than the sheet resistance of the first conductive layer and the third conductive layer.   The dye-sensitized solar cell module according to claim 3, wherein the sheet resistance of the second conductive layer and the fourth conductive layer is 2 Ω / □ or less.   5. The dye-sensitized dye according to claim 1, wherein in the second photoelectric conversion element, the porous insulating layer has a dye having a unit dye adsorption amount smaller than a unit dye adsorption amount of the porous semiconductor layer. Solar cell module.   The dye-sensitized solar cell module according to claim 5, wherein in the second photoelectric conversion element, the unit dye adsorption amount of the porous insulating layer is 0.1 times or less the unit dye adsorption amount of the porous semiconductor layer.   The porous insulating layer of the second photoelectric conversion element is composed of one or more selected from the group consisting of silicon oxide, rutile titanium oxide, niobium oxide, zirconium oxide, and aluminum oxide. 2. A dye-sensitized solar cell module according to 1.   The dye-sensitized solar cell module according to any one of claims 1 to 7, wherein a film thickness of the porous insulating layer of the second photoelectric conversion element is 0.05 µm or more and 5 µm or less. Comprising a step of forming a first photoelectric conversion element and a second photoelectric conversion element on a substrate, the step comprising:
A first conductive layer, a porous semiconductor layer, a porous insulating layer, a catalyst layer, and a second conductive layer are laminated in this order on the first photoelectric conversion element forming region on the substrate, and the second photoelectric layer on the substrate is stacked. A step of laminating a third conductive layer, a catalyst layer, a porous insulating layer, a porous semiconductor layer, and a fourth conductive layer in this order in the conversion element forming region; and
Impregnating the laminate with a dye solution to adsorb the dye to at least the porous semiconductor layer; and
Removing the pigment from the porous insulating layer;
A method for producing a dye-sensitized solar cell module, comprising a step of impregnating a porous semiconductor layer and a porous insulating layer with an electrolyte. In the second photoelectric conversion element formation region in the step of forming the laminate, the mixed material containing the porous insulating layer forming material and the metal oxide fine particles is applied onto the catalyst layer and baked, and the metal oxide fine particles Forming a porous insulating layer having a coating film comprising:
The dye enhancement according to claim 9, wherein, in the step of removing the dye, the laminate is immersed in an acidic solution, and the coating film adsorbing the dye is dissolved in the acidic solution and removed together with the dye from the porous insulating layer. Manufacturing method of sensitive solar cell module.   The method for producing a dye-sensitized solar cell module according to claim 10, wherein the metal oxide fine particles comprise one or more selected from the group consisting of magnesium oxide, zinc oxide, nickel oxide and molybdenum oxide. Comprising a step of forming a first photoelectric conversion element and a second photoelectric conversion element on a substrate, the step comprising:
A first conductive layer, a porous semiconductor layer, a porous insulating layer, a catalyst layer, and a second conductive layer are laminated in this order on the first photoelectric conversion element forming region on the substrate, and the second photoelectric layer on the substrate is stacked. A step of laminating a third conductive layer, a catalyst layer, a porous insulating layer, a porous semiconductor layer, and a fourth conductive layer in this order in the conversion element forming region; and
Impregnating the laminate with a dye solution to adsorb the dye to at least the porous semiconductor layer; and
Comprising a step of impregnating a porous semiconductor layer and a porous insulating layer with an electrolyte;
In the second photoelectric conversion element forming region in the step of forming a laminate, a porous insulating layer is formed by applying and baking a sol solution or suspension containing silicon atoms as a porous insulating layer forming material on the catalyst layer. A method for producing a dye-sensitized solar cell module, wherein   The method for producing a dye-sensitized solar cell module according to claim 12, wherein the sol solution contains a polymer compound.

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