JP4897226B2 - Dye-sensitized solar cell and dye-sensitized solar cell module - Google Patents

Description

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

  As an energy source to replace fossil fuels, solar cells that can convert sunlight into electric power have attracted attention. At present, some solar cells and thin film silicon solar cells using a crystalline silicon substrate are beginning to be put into practical use. However, the former has a problem that the manufacturing cost of the silicon substrate is high, and the latter has a problem that the manufacturing cost becomes high because it is necessary to use various semiconductor manufacturing gases and complicated apparatuses. 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, Japanese Patent No. 2664194 (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 material composed of a photoelectric conversion material having an absorption spectrum in the visible light region by adsorbing a photosensitizing dye between electrodes of two glass substrates having electrodes formed on the surface, and an electrolyte material. The conversion layer is sandwiched between them.
When this wet solar cell is irradiated with light, electrons are generated in the photoelectric conversion layer, the generated electrons move to an electrode through an external electric circuit, and the moved electrons are transferred to the opposite electrode by ions in the electrolyte. Return to the photoelectric conversion layer. Electrical energy is extracted by such a series of electron flows.

  Japanese Unexamined Patent Publication No. 2000-91609 (Patent Document 2) discloses a technique for manufacturing a wet solar cell having the above-described operating principle at low cost. According to the manufacturing technique, a laminate of a platinum conductive film (electrode) and a titanium dioxide colloidal power generation layer is formed by a coating means on a flexible substrate that can be wound up, and the electrolyte solution is added during or after the formation of the laminate. By laminating a glass substrate on which a power generation layer is impregnated and further formed with a transparent conductive film (electrode), a single unit organic solar cell can be produced.

However, since the above-described wet solar cell has a basic structure in which an electrolyte is injected between the electrodes of two glass substrates, even if a prototype of a small area solar cell is possible, Application to such a large area solar cell is difficult.
In such a solar cell, when the area of one solar cell (unit cell) is increased, the generated current increases in proportion to the area, but the lateral resistance component of the transparent conductive film used for the electrode portion is extremely large. In order to increase, the internal series electric resistance as a solar cell increases. As a result, there is a problem that the fill factor (FF) in the current-voltage characteristics at the time of photoelectric conversion is lowered and the photoelectric conversion efficiency is lowered.

  Moreover, in the manufacturing process of the wet solar cell, a titanium oxide film is formed on a glass substrate with an electrode (transparent conductive film), and this is baked at, for example, about 450 ° C. for at least 30 minutes. A semiconductor layer may be obtained. In such firing, the glass substrate and the electrode are warped due to the difference in expansion coefficient between the constituent members, and the titanium oxide formed thereon is fired in a warped state. Such a problem does not cause a large problem in a small area solar cell, but when manufacturing a large area solar cell, particularly a plurality of batteries, the distance between the semiconductor layer and the counter electrode (cell gap) is constant. In other words, it causes variations in battery performance. Furthermore, there is a case where the titanium oxide of the semiconductor layer and the counter electrode are in contact with each other, and a part thereof is short-circuited.

  Japanese Patent Laid-Open No. 2001-345126 (Patent Document 3) provides a porous support made of a filtration filter, a separator, a nonwoven fabric, or the like between a semiconductor layer that is a photoelectric conversion material and a counter electrode, and an electrolyte. There has been disclosed a wet solar cell in which an electrolyte as a material is prevented from leaking from the periphery of the solar cell.

  However, when the wet solar cell has different electrolyte wettability with respect to the porous support and the semiconductor layer titanium oxide, either the porous support or the semiconductor layer is injected even if a certain amount of electrolyte is injected. On the other hand, there is a problem that the electrolyte solution is biased and causes a decrease in battery performance.

International Publication No. WO97 / 16838 (Patent Document 4) discloses a dye-sensitized solar cell module in which a plurality of dye-sensitized solar cells are connected in series.
This dye-sensitized solar cell module has a structure in which a titanium oxide layer, an insulating porous layer, and a counter electrode are sequentially laminated on a glass substrate in which a transparent conductive film (electrode) is formed into a strip shape. A battery is formed and arranged in series so that the counter electrode is in contact with the adjacent dye-sensitized solar cell.

  However, in the above dye-sensitized solar cell module, after forming an intermediate porosity using particles such as about 10 μm of titanium oxide on the titanium oxide layer, an electrolytic solution that is an electrolyte material is injected by a capillary phenomenon. There is a problem that the electrolyte cannot be uniformly injected depending on the state of the titanium oxide layer and the intermediate porous layer.

Japanese Patent No. 2664194 JP 2000-91609 A JP 2001-345126 A International Publication No. WO97 / 16838 Pamphlet

  In the case of using a gel electrolyte obtained by injecting and polymerizing a precursor monomer into a porous support and a semiconductor layer instead of an electrolyte solution as an electrolyte material in a wet solar cell, the present inventors also use a gel electrolyte, Due to the difference in wettability of the precursor monomer with respect to the porous support and the semiconductor layer, the gel electrolyte is biased in either the porous support or the semiconductor layer, and there is a problem of causing a decrease in battery performance. It was newly found that there are problems such as peeling of the porous support.

  Therefore, the present invention has an object to provide a dye-sensitized solar cell that is stable, has excellent photoelectric conversion efficiency, and is suitable for increasing the area, and a dye-sensitized solar cell module using the same. To do.

  As a result of intensive studies to solve the above problems, the present inventors have found that at least one of the first support and the second support made of a light transmissive material is placed on the first support. A first conductive layer provided; a porous photoelectric conversion layer in which a dye is adsorbed on the porous semiconductor layer; a carrier transport layer comprising a liquid or a gel electrolyte; and a second conductive layer provided in contact with the second support; In the dye-sensitized solar cell comprising: a porous layer is further provided between the porous photoelectric conversion layer and the second conductive layer, and the capillary force against the liquid of the porous layer or the gel electrolyte and the liquid of the porous photoelectric conversion layer or By setting the ratio of the capillary force to the gel electrolyte within a specific range, the carrier transport layer is not biased in any of the porous photoelectric conversion layer and the porous layer, and does not cause deterioration in battery performance. Excellent photoelectric conversion efficiency And, and we found that to obtain a large area dye-sensitized suitable reduction solar cells and dye-sensitized solar cell module using the same, and have completed the present invention.

Thus, according to the present invention, the first conductive layer provided on the first support and the porous semiconductor layer between the first support and the second support, at least one of which is made of a light transmissive material. A porous photoelectric conversion layer having a dye adsorbed thereon, a carrier transport layer made of a liquid or gel electrolyte, and a second conductive layer provided in contact with the second support, and the porous photoelectric conversion layer and the second conductive layer A porous layer is further provided between the layers, and the porous semiconductor layer and the porous layer have a capillary force P _T [Pa] against the liquid or gel electrolyte of the porous layer represented by the following formula :
P _T = 2σ · cos θ _T / r _T
(Where σ is the surface tension [N / m] of the liquid or gel electrolyte , θ _T is the contact angle [°] between the liquid or gel electrolyte and the porous layer material, and r _T is the pore of the porous layer. Radius [m])
And the capillary force P _K [Pa] for the liquid or gel electrolyte of the porous photoelectric conversion layer represented by the following formula :
P _K = 2σ · cos θ _K / r _K
(In the formula, σ is the surface tension [N / m] of the liquid or gel electrolyte , θ _K is the contact angle [°] between the liquid or gel electrolyte and the porous photoelectric conversion layer material, and r _K is porous. It is the pore radius [m] of the photoelectric conversion layer)
Thus, a dye-sensitized solar cell is provided, which is a combination of layers having a ratio (P _T / P _K ) in the range of 0.2 to 5 .

  According to the present invention, there is provided a dye-sensitized solar cell module characterized in that at least two or more of the dye-sensitized solar cells are connected in series and integrated.

  According to the present invention, it is possible to provide a dye-sensitized solar cell that is stable, has excellent photoelectric conversion efficiency, and is suitable for increasing the area, and a dye-sensitized solar cell module using the same.

The dye-sensitized solar cell of the present invention (hereinafter referred to as “solar cell”) is provided on the first support between the first support and the second support, at least one of which is made of a light-transmitting material. A first conductive layer provided; a porous photoelectric conversion layer in which a dye is adsorbed to the porous semiconductor layer; and a second conductive layer provided in contact with the second support when made of a liquid or gel electrolyte, A porous layer is further provided between the conductive photoelectric conversion layer and the second conductive layer, and the porous semiconductor layer and the porous layer are a layer in which the liquid or gel electrolyte can permeate the porous semiconductor layer and the porous layer evenly. It is characterized by that.
Here, “can penetrate without bias” means that the carrier transport layer is not biased in either the porous photoelectric conversion layer or the porous layer.

In order for the porous semiconductor layer and the porous layer to be a layer in which the liquid or gel electrolyte can permeate the porous semiconductor layer and the porous layer evenly, the porous semiconductor layer and the porous layer are expressed by the following formula: Capillary force P _T [Pa] on the liquid or gel electrolyte of the layer:
P _T = 2σ · cos θ _T / r _T
(Where σ is the surface tension [N / m] of the liquid or gel electrolyte, θ _T is the contact angle [°] between the liquid or gel electrolyte and the porous layer material, and r _T is the pore of the porous layer. Radius [m])
And the capillary force P _K [Pa] for the liquid or gel electrolyte of the porous photoelectric conversion layer represented by the following formula:
P _K = 2σ · cos θ _K / r _K
(In the formula, σ is the surface tension [N / m] of the liquid or gel electrolyte, θ _K is the contact angle [°] between the liquid or gel electrolyte and the porous photoelectric conversion layer material, and r _K is porous. It is the pore radius [m] of the photoelectric conversion layer)
And a ratio of layers (P _T / P _K ) is preferably a combination of layers in a range of 0.2 to 5.

A preferred embodiment of the solar cell of the present invention will be described with reference to the drawings. In addition, this embodiment is an example and implementation with a various form is possible within the scope of the present invention.
FIG. 1 is a schematic cross-sectional view showing the layer structure of the solar cell of the present invention.
In FIG. 1, 1 is a first support 1, 2 is a first conductive layer, 3 is a porous photoelectric conversion layer in which a dye is adsorbed on a porous semiconductor layer, 4 is a carrier transport layer, 5 is a porous layer, and 6 is a porous layer. The second conductive layer, 7 is a second support, 8 is a sealing material, and 9 is a catalyst layer.

First, the capillary force will be described.
Generally, when a substance penetrates into a porous body having pores, the penetration is driven by a capillary force against the porous body substance. For example, when a liquid permeates a circular tube having a pore radius r, the permeating propulsive force can be expressed by the following capillary force P.
P = 2σ · cos θ / r
(Wherein P is the capillary force [Pa], σ is the surface tension of the liquid [N / m], θ is the contact angle [°] between the liquid and the circular tube, and r is the pore of the circular tube. Radius [m])

In general, when a liquid penetrates into a porous body having separate pores in a layered manner, the capillary force P becomes a driving force at each pore portion, and the liquid penetrates, but the pore radius, surface tension, contact angle, etc. The liquid predominantly penetrates into the layer where the capillary force due to each physical property value is large.
Furthermore, when the liquid penetrates into each layer and is held in a state where a part that has not penetrated remains, the penetration gradually proceeds to a layer with a large capillary force, and penetrates and fills a layer with a small capillary force. A situation occurs in which liquid is sucked up.

A porous layer is provided between the porous photoelectric conversion layer in which the dye is adsorbed on the porous semiconductor layer and the second conductive layer, and a carrier transport layer such as an electrolyte is provided between the first support and the second support. When injected, the above situation occurs, the carrier transport layer cannot be formed uniformly, and a stable and excellent solar cell having a high photoelectric conversion efficiency cannot be obtained.
Therefore, in the present invention, a solar cell is manufactured with a configuration in which the capillary force of the porous layer and the capillary force of the porous photoelectric conversion layer are at the same level.

  First, constituent members, a porous photoelectric conversion layer, a porous layer and a carrier transport layer important in the present invention, and a method for forming the same will be described.

(Porous photoelectric conversion layer)
The porous photoelectric conversion layer is formed by adsorbing a dye to the porous semiconductor layer.

(Porous semiconductor)
The porous semiconductor layer is composed of a semiconductor, and various forms such as a particle form and a film form can be used, but a film form is preferable.
Examples of the material constituting the porous semiconductor layer include well-known semiconductors such as titanium oxide, zinc oxide, tungsten oxide, barium titanate, strontium titanate, cadmium sulfide, and combinations of one or more of these. Among these, titanium oxide or zinc oxide is particularly preferable from the viewpoints of photoelectric conversion efficiency, stability, and safety.

  The method for forming a film-like porous semiconductor layer on a support (also referred to as “substrate”) on which a conductive layer is formed is not particularly limited, and various known methods can be mentioned. Specifically, (1) a method in which a suspension (paste) containing semiconductor particles is applied onto a substrate by a screen printing method, an ink jet method, and the like, followed by firing, (2) a CVD method using a source gas Alternatively, a method of forming a film on a substrate by MOCVD method or the like, (3) a method of forming a film on a substrate by PVD method using a raw material solid, vapor deposition method, sputtering method, or the like, (4) sol-gel method, electricity Examples thereof include a method of forming a film on a substrate by a method using a chemical oxidation-reduction reaction.

Among the above methods, a screen printing method using a suspension is particularly preferable because a thick porous semiconductor layer can be produced at low cost.
When the porous semiconductor layer is printed by the screen printing method, it may be printed in several times in order to reduce sagging after printing. Moreover, when printing in several times, you may print using the suspension containing the semiconductor particle which has a different material and a particle size.

  Examples of the semiconductor particles include commercially available single or compound semiconductor particles having an average particle size of about 1 to 500 nm (for example, 20 nm). The porous semiconductor layer may contain semiconductor fine particles having different particle diameters. In the present specification, the “average particle diameter” means a value measured by SEM observation.

In order to improve the photoelectric conversion efficiency of the solar cell, it is necessary to adsorb more dye, which will be described later, to the porous semiconductor layer. For this reason, the membrane-like porous semiconductor layer preferably has a large specific surface area, and is preferably about 10 to 200 m ² / g. In this specification, “specific surface area” means a value measured by the BET adsorption method.

  Examples of the solvent used for preparing the suspension containing semiconductor particles include a glyme solvent such as ethylene glycol monomethyl ether, an alcohol solvent such as isopropyl alcohol, a mixed solvent such as isopropyl alcohol / toluene, and water. .

When the porous semiconductor layer is printed by the screen printing method, drying and firing are performed by appropriately setting conditions such as temperature, time, atmosphere, and the like depending on the substrate to be used and the type of semiconductor particles. For example, the temperature is about 50 to 800 ° C., the time is about 10 seconds to 12 hours, and the atmosphere is air or an inert gas atmosphere. This drying and baking may be performed once at a single temperature or twice or more by changing the temperature.
Although the film thickness of a porous semiconductor layer is not specifically limited, About 0.5-100 micrometers is preferable from viewpoints, such as optical transparency and photoelectric conversion efficiency.

(Dye)
Examples of the dye that functions as a photosensitizer by being adsorbed on the porous semiconductor layer include those having absorption in various visible light regions and / or infrared light regions. In order to firmly adsorb the dye to the porous semiconductor layer, the carboxylic acid group, carboxylic anhydride group, alkoxy group, hydroxyl group, hydroxyalkyl group, sulfonic acid group, ester group, mercapto group, Those having an interlock group such as a phosphonyl group 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 dyes containing an interlock group include ruthenium bipyridine dyes, azo dyes, quinone dyes, quinone imine dyes, quinacridone dyes, squarylium dyes, cyanine dyes, merocyanine dyes, triphenylmethane dyes, Xanthene dyes, porphyrin dyes, phthalocyanine dyes, berylene dyes, indigo dyes, naphthalocyanine dyes and the like can be mentioned.

Examples of the method of adsorbing the porous semiconductor layer include a method of immersing the porous semiconductor layer formed on the substrate in a solution in which a dye is dissolved (dye adsorption solution).
The solvent for dissolving the dye may be any solvent that dissolves the dye. Specifically, alcohols such as ethanol, ketones such as acetone, ethers such as diethyl ether and tetrahydrofuran, and nitrogen compounds such as acetonitrile. Halogenated aliphatic hydrocarbons such as chloroform, aliphatic hydrocarbons such as hexane, aromatic hydrocarbons such as benzene, esters such as ethyl acetate, water, and the like. Two or more of these solvents can be used in combination.
The concentration of the dye in the solution can be appropriately adjusted depending on the kind of the dye and the solvent to be used, but is preferably as high as possible in order to improve the adsorption function, for example, 5 × 10 ⁻⁴ mol / liter. That is all you need.

(Porous layer)
The porous layer is provided between the porous photoelectric conversion layer and the second conductive layer or the catalyst layer, and is provided to electrically separate each of them.

The material constituting the porous layer is not particularly limited as long as it does not hinder charge transport of the filled (penetrated) carrier transport layer and has a capillary force equivalent to that of the porous photoelectric conversion layer. For example, the separator used for a secondary battery etc., a nonwoven fabric, a filtration filter, etc. are mentioned.
The material of the separator includes polyolefins such as polypropylene and polyethylene, polyesters such as polyethylene terephthalate, polyamides, polyferylene sulfide, vinylon (a copolymer of vinyl chloride and vinyl acetate), polyimide, and vinylon (acetalized polyvinyl alcohol). ) And the like.
Examples of the material of the filtration filter include glass fibers, polyolefins such as polypropylene and polyethylene, and polyesters such as polyethylene terephthalate.

The pore radius and film thickness of the porous layer are not particularly limited, but are preferably about 1 nm to 10 μm and about 1 to 50 μm, respectively, from the viewpoints of light transmittance and photoelectric conversion efficiency.
Examples of the porous layer include a polyester separator (referred to as “porous layer A”) having a pore radius of 50 nm and a film thickness of 25 μm.

  Further, the porous layer can also be produced by a method similar to the method for producing the porous photoelectric conversion layer using insulating particles. Examples of the insulating particles include tungsten oxide, glass, aluminum oxide, silicon oxide, titanium oxide, and zirconia oxide. Therefore, by using a material having a conduction band level higher than the conduction band level of the porous photoelectric conversion layer material, a solar cell is formed by forming a porous layer with a material lower than the conduction band level of the porous photoelectric conversion layer material. The leakage current is reduced and the performance is improved.

(Carrier transport layer)
The carrier transport layer is a layer containing a conductive material that can transport electrons, holes, and ions, and is filled between the porous photoelectric conversion layer and the second conductive layer.
Examples of the conductive material include a hole transport material such as polycarbazole, an electron transport material such as tetranitrofluororenone, a conductive polymer such as polyroll, a polymer electrolyte obtained by solidifying a liquid electrolyte with a polymer compound, and iodide. Examples thereof include p-type semiconductors such as copper and copper thiocyanate, and electrolytes obtained by solidifying liquid electrolytes containing molten salts with fine particles.
The carrier transport layer may be any of a liquid electrolyte, a gel electrolyte, and a molten salt gel electrolyte.

A liquid electrolyte (also referred to as an electrolytic solution) includes an electrolyte and a solvent.
As the electrolyte, 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, I combination of _{2; LiBr, NaBr, KBr,} CsBr, CaBr metal bromide such as _2, and tetraalkyl ammonium bromide, and bromide such as bromine salts of quaternary ammonium compounds such as pyridinium bromide, combination of Br _2; ferrocyanide acid Metal complexes such as salt-ferricyanate and ferrocene-ferricinium ions; sulfur compounds such as sodium polysulfide and alkylthiol-alkyldisulfides; viologen dyes, hydroquinone-quinones and the like. Among these, the combination of LiI, pyridinium iodide, imidazolium iodide and I ₂ is preferable from the viewpoint of improving the open circuit voltage. Two or more of the above electrolytes may be mixed and used.

  Solvents include 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, propylene glycol dialkyl ether, polyethylene glycol dialkyl ether , Polypropylene glycol dialkyl ether, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, ethers such as polyethylene glycol monoalkyl ether, polypropylene glycol monoalkyl ether; alcohols such as methanol and ethanol; ethylene glycol, propylene glycol, polyethylene glycol , Polypropylene glycol, Polyhydric alcohols such as glycerin; acetonitrile, glutarodinitrile, methoxy acetonitrile, propionitrile, nitrile compounds such as benzonitrile; like water; dimethyl sulfoxide, aprotic polar substances such as sulfolane.

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.

The electrolyte concentration of the carrier transport layer may be appropriately set depending on the type of electrolyte and solvent, and is, for example, 0.01 to 1.5 mol / liter, preferably 0.01 to 0.7 mol / liter.
Examples of the electrolyte include dimethylpropylimidazolium iodide 0.6 mol / liter, lithium iodide 0.1 mol / liter, iodine 0.1 mol / liter, and tertiary butylpyridine 0.5 mol / liter. What dissolved each in acetonitrile so that it may become.

Next, the capillary force when a specific material is used will be described.
The capillary force in the case of using a porous semiconductor layer composed of the above electrolytic solution, porous layer A and titanium oxide was calculated based on the above formula. That is, the calculation was performed assuming that the liquid in the equation is an electrolyte and the circular tube is titanium oxide that is a material for the porous photoelectric conversion layer.

The following formula:
R = ΔV / Δlog (R _K ) [mm ³ / nm · g]
(Where R _K is the pore radius [nm], ΔV is the pore volume per unit weight, and Δlog (R _K ) is the change in pore radius)
The relationship of the peak Rp of the pore volume change rate R in the pore radius distribution characteristic of the porous photoelectric conversion layer represented by is shown in FIG. From this figure, the peak Rp was 57.6 nm.
The contact angle θ was defined as the contact angle between the bulk material (anatase type titanium oxide) forming the porous layer and the porous photoelectric conversion layer and the electrolyte solution as the carrier transport layer.
As a result of the calculation, the capillary force P _T for the electrolyte solution of the porous layer (separator) is 911787 Pa, the capillary force P _K for the electrolyte solution of the porous photoelectric conversion layer is 857453 Pa, and P _T / P _K is 1.06. there were.
As a result of injecting about 30 μl of the electrolyte having such a driving force into the porous photoelectric conversion layer and the porous layer by using a capillary phenomenon, and evaluating the solar cell characteristics about 5 minutes after the injection, the conversion efficiency is 6. It was 47%.

As another porous layer, a polyester porous layer (referred to as “porous layer B”) having a pore radius of 500 nm and a film thickness of 25 μm, a polyester porous layer having a pore radius of 20 nm and a film thickness of 25 μm (“porous layer C”). A solar cell was prepared and evaluated in the same manner as described above except that the above was used.
As a result, in the case of the porous layer B, P _T / P _K was 0.11, and the conversion efficiency was 4.51%. In the case of porous layer C, P _T / P _K was 2.66, and the conversion efficiency was 6.26%.

After evaluating the performance of the solar cell, only the porous layer was taken out, the titanium oxide surface was wiped off with Kimwipe (registered trademark), and weighed to calculate the weight difference before and after cell preparation. 3.5 mg (cell using porous layer A) ), 1.8 mg (cell using porous layer B) and 3.8 mg (cell using porous layer C).
As described above, high conversion efficiency could be obtained by using a porous layer having the same capillary force as that of the porous photoelectric conversion layer. This is presumably because the electrolyte solution was uniformly injected into the porous photoelectric conversion layer and the porous layer.

Furthermore, the result of having evaluated the performance of the solar cell using the porous layer from which capillary force differs is shown in FIG.
From this result, the ratio (P _T / P _K ) of the capillary force P _T for the liquid or gel electrolyte of the porous layer represented by the above formula and the capillary force P _K for the liquid or gel electrolyte of the porous photoelectric conversion layer is 0. It can be seen that the FF is greatly reduced at 2 or less and 5 or more. This is thought to be due to the non-uniformity of the electrolyte due to the large difference in the ratio of capillary forces.
Accordingly, the ratio of the capillary forces (P _T / P _K ) is preferably in the range of 0.2-5.

  Next, using a porous layer A and using a titanium oxide having an area of 5 mm × 80 mm as a porous photoelectric conversion layer, a large-area unit cell solar cell was prepared and evaluated. In addition, 10 each using a porous layer and one not using were produced, and examination was performed regarding variation in each conversion efficiency. The obtained results are shown in Table 1.

  From the results in Table 1, when a large-area solar cell is produced, the cell gap varies due to warpage when the porous photoelectric conversion layer that is titanium oxide is baked, which affects the conversion efficiency. It can be seen that a certain solar cell can be produced by setting the layers.

  Based on the titanium oxide paste (titanium oxide paste E) described in the production example of the following solar cell unit cell, the titanium oxide paste A has 9 nm of titanium oxide particles, the titanium oxide paste B has 17 nm of titanium oxide particles, and the titanium oxide paste. C was prepared with a titanium oxide solid concentration of 15 wt%, ethyl cellulose with 7 wt%, titanium oxide paste D with 8 wt% ethyl cellulose, and titanium oxide paste F with 15 wt% ethyl cellulose. FIG. 4 shows the pore distribution characteristics of each porous photoelectric conversion layer.

  The result of having produced the solar cell using the above-mentioned separator C using these porous photoelectric conversion layers and performing performance evaluation is shown in FIG. From this result, it can be seen that the pore radius of the porous photoelectric conversion layer exhibits good performance in the range of 20 to 60 nm. The capillary force ratio is 0.25, 0.36, 1.03, 1.68, 2.66, 3.35 in order of titanium oxide paste A to F, and these are 0.25 to 3.35. It was in range.

  Hereinafter, the constituent material of the solar cell and the formation method thereof will be described.

(First support and second support)
Since the first support and the second support (collectively referred to as “supports”) need to be light transmissive at the portion that becomes the light receiving surface of the solar cell, at least one of them is made of a light transmissive material. For example, by using a light transmissive material for the first support, a solar cell capable of light incidence from the first support side can be obtained. In this case, in order to use incident light effectively, the opaque second support is preferably made of a material such as a metal capable of reflecting incident light.
Moreover, it is good also as a solar cell in which the light incidence from both surfaces is possible, using a light-transmitting material for both surfaces.
In the present invention, “light-transmitting” means substantially transmitting light having a wavelength having effective sensitivity to at least the dye of the porous photoelectric conversion layer, and not necessarily for light in all wavelength regions. It does not mean having transparency.

As a material constituting the support, a material having heat resistance of 250 ° C. or higher is preferable, and the thickness is preferably about 0.2 to 5 mm.
Examples of the material constituting the support include glass substrates such as soda glass, fused quartz glass, crystalline quartz glass, and synthetic quartz glass, heat resistant resin plates such as flexible films, and metal plates.
Examples of the flexible film (hereinafter referred to as “film”) include long-term weather-resistant sheets and films such as polyester, polyacryl, polyimide, Teflon (registered trademark), polyethylene, polypropylene, and polyethylene terephthalate (PET). .

When forming another layer with heating on the support, for example, when forming a conductive layer with heating at about 250 ° C. on the first support, among the above film materials, 250 ° C. Teflon (registered trademark) having the above heat resistance is particularly preferable.
In the case where there is no heating step after forming the support, the support may not have heat resistance.

The support may have a recess for embedding the first conductive layer and the second conductive layer.
Moreover, a support body can be utilized when attaching the completed solar cell to another structure. That is, the peripheral part of a support such as a glass substrate can be easily attached to another support using metal processed parts and screws.

(First conductive layer and second conductive layer)
The first conductive layer and the second conductive layer (collectively referred to as “conductive layer”) are formed on the first support and the second support, respectively. Since light transmittance is required, at least one is made of a light transmissive material.
A conductive layer having a function of collecting electrons generated on one side of the support is also referred to as a “collecting electrode layer”, and a pair of conductive layers is also referred to as a “counter electrode layer”.

As the material constituting the conductive layer, ITO (indium-tin composite oxide), IZO (indium-zinc composite oxide), tin oxide doped with fluorine, zinc oxide doped with boron, gallium or aluminum, or doped with niobium Gold, silver, aluminum, indium, platinum, carbon (carbon black, graphite, glass carbon, amorphous carbon, hard carbon, soft carbon, carbon whisker, carbon nanotube, fullerene), such as transparent conductive metal oxides such as titanium oxide Etc.
When the conductive layer is generally made of an opaque metal material, it may be made transparent by thinning.

The method for forming the conductive layer on the support is not particularly limited, and a metal or alloy thin plate is affixed by CVD, sputtering, electroless plating, electrodeposition, printing, adhesive or double-sided tape. In general, a method of forming an electrode can be used.
Further, it is preferable that the support and the conductive layer are made of the same material because the manufacturing process can be simplified.
The film thickness of the thin conductive layer is about 0.01 to 2 μm.
Further, it is not necessary to reduce the thickness of an opaque conductive layer that does not require light transmission.

  The conductive layer serving as the counter electrode layer preferably has a catalytic function for the redox reaction of the carrier transport layer described later, and the counter electrode layer is formed of a layer of platinum having catalytic ability, or the catalyst on the side in contact with the carrier transport layer. It is preferable to provide two or more layers by providing a layer of platinum or the like having a function.

(Catalyst layer)
A catalyst layer is preferably formed on the surface of the first conductive layer or the second conductive layer with respect to the porous layer. A catalyst layer contributes to the improvement of the conversion efficiency of a solar cell.
As the material constituting the catalyst layer, a material having a work function lower than the conduction band level of the porous semiconductor layer and activating the redox reaction of the carrier transport layer is preferable.
For example, when titanium oxide (work function: 4.17 eV) is used for the porous semiconductor layer, platinum (work function: 6.35 eV), carbon black, graphite, glass carbon, amorphous carbon, hard carbon, soft carbon, Carbon (work function 4.78 eV) such as carbon whisker, carbon nanotube, and fullerene is preferable.

(Encapsulant)
The sealing material is preferably provided in order to prevent volatilization of the electrolyte solution in 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 encapsulant, a silicone resin, an epoxy resin, a polyisobutylene resin, a hot melt resin, a glass frit, and the like are preferable. These can be used in two or more layers. 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 pattern of the sealing material is by using a dispenser when using a silicone resin, an epoxy resin, or a glass frit, and when using a hot melt resin, by opening a patterned hole in the sheet-like hot melt resin, Can be formed.
What is necessary is just to set the thickness of the layer direction of a sealing material according to the film thickness of the constituent material between support bodies.

  Using the above-mentioned materials, a porous photoelectric conversion layer made of titanium oxide is sized in a size of 1 cm × 8 cm on fluorine-doped tin oxide that is a first conductive layer formed on glass that is a first support. It was made with. As a result of measuring the pore distribution characteristics of the titanium oxide porous photoelectric conversion layer, the distribution shown in FIG. 2 was obtained. From FIG. 2, the main pore radius of this titanium oxide porous photoelectric conversion layer is 57.6 nm.

  The porous photoelectric conversion layer was adsorbed with a ruthenium dye of the following formula (trade name: Ruthenium 719, manufactured by Solaronix).

On the other hand, a platinum layer having a thickness of about 300 nm was formed on the second support and the second conductive layer having the same structure as the first support and the first conductive layer by sputtering.
A separator, which is a porous body having the same size as the porous photoelectric conversion layer, is placed on the porous photoelectric conversion layer on which the dye is adsorbed, and the second support and the second support are placed on the separator so that the platinum layer is in contact with the separator. A conductive layer is installed to manufacture a solar cell.

The dye-sensitized solar cell module (hereinafter referred to as “solar cell module”) of the present invention is formed by integrating at least two or more of the solar cells of the present invention in series.
And the solar cell module of the present invention is
(1) The first conductive layer on the first support of the dye-sensitized solar cell is electrically connected to the second conductive layer on the second support of another dye-sensitized solar cell adjacent thereto. Or
(2) The first conductive layer on the first support of the dye-sensitized solar cell and the second conductive layer on the first support of another dye-sensitized solar cell adjacent thereto are configured as the same layer. It is preferable.

(Example)
The present invention will be described more specifically with reference to production examples and examples. However, the present invention is not limited to these production examples and examples.
In Examples, unless otherwise specified, solar cells (solar cell unit cells) and solar cell modules were manufactured using the conditions of the manufacturing examples. For convenience, the manufacturing examples are divided into the solar cell manufacturing example and the solar cell module manufacturing example. However, the manufacturing process in the solar cell manufacturing example may be used as appropriate for solar cell module manufacturing, and vice versa. May be.
The schematic cross-sectional views of the solar cell and the solar cell module of the present invention used in the following description are all examples, and the present invention is not limited by these drawings.

(Production example of solar cell unit cell)
FIG. 1 is a schematic cross-sectional view showing the layer structure of the solar cell of the present invention.
A solar cell as shown in FIG. 1 was produced. The manufacturing process is shown below.
In FIG. 1, 1 is a first support (also referred to as a substrate), 2 is a first conductive layer, 3 is a porous photoelectric conversion layer in which a dye is adsorbed on a porous semiconductor layer, 4 is a carrier transport layer, and 5 is porous. A layer (assumed to be filled with a carrier transport material), 6 is a second conductive layer, 7 is a second support, 8 is a sealing material, and 9 is a catalyst layer.

On one surface of the first support 1 made of a glass substrate having a thickness of approximately 1.1 mm, SnO ₂ having a thickness of approximately 900 nm was formed as a first conductive layer ₂ by CVD. The glass substrate and SnO ₂ have a heat resistance of 450 ° C. or higher.

A metal oxide TiO ₂ powder is mixed with a solvent and a binder to form a slurry or paste, and this is screen printed at a predetermined position on the first support 1 using a screen plate on which a pattern is separately formed. Then, after the leveling, it was dried in an oven at 80 ° C. and baked at 500 ° C. in the air to produce a porous semiconductor layer having a thickness of about 20 μm.

  Specifically, 125 ml of titanium isopropoxide (manufactured by Kishida Chemical Co., Ltd.) was dropped into 750 mL of a 0.1 M aqueous nitric acid solution (manufactured by Kishida Chemical Co., Ltd.) and hydrolyzed. A sol solution was obtained by heating for a period of time. The obtained sol solution was treated at 230 ° C. for 11 hours in a titanium autoclave for particle growth and then subjected to ultrasonic dispersion for 30 minutes, whereby titanium oxide particles having an average primary particle size of 20 nm (“titanium oxide A”). A colloidal solution containing

  The obtained colloidal solution was slowly concentrated with an evaporator until the titanium oxide concentration became 15 wt%. In the obtained concentrated liquid, commercially available titanium oxide particles (Nippon Aerosil Co., Ltd., trade name P-25, anatase type: rutile type = (7: 3) mixed, average primary particle size 20 nm: “titanium oxide B”. ), Ethanol twice the volume of the colloidal solution was added, and the mixture was centrifuged at a rotational speed of 5000 rpm. After the obtained titanium oxide particles were washed with ethanol, ethyl cellulose (manufactured by Kishida Chemical Co., Ltd.) and terpineol (manufactured by Kishida Chemical Co., Ltd.) dissolved in absolute ethanol were added and stirred to disperse the titanium oxide particles. It was. Thereafter, ethanol was evaporated at 50 ° C. under a vacuum of 40 mbar to obtain a titanium oxide paste. The final composition was adjusted to have a titanium oxide solid concentration of 20 wt%, ethyl cellulose of 10 wt%, and terpineol of 64 wt%.

The obtained titanium oxide paste was printed on the first support 1 with a screen printing machine (LS-150 manufactured by Neurong Seimitsu Kogyo) to obtain a porous semiconductor layer.
When the pore distribution characteristic of the porous semiconductor layer was measured, the pore radius was 57.6 nm.

Next, the 1st support body 1 in which the 1st conductive layer 2 and the porous semiconductor layer were formed are immersed in a pigment | dye solution, it recirculate | refluxs for about 2 hours, a pigment | dye is made to adsorb | suck to a porous semiconductor layer, and a porous photoelectric converting layer 3 was obtained.
Specifically, ruthenium dye of the above formula (manufactured by Solaronix, trade name Ruthenium 719) is dissolved at a concentration of 4 × 10 ⁻⁴ mol / liter in a solvent in which acetonitrile and n-butanol ethanol are mixed at a volume ratio of 1: 1. Thus, a dye solution for adsorption was obtained. The obtained dye solution for adsorption and the substrate obtained above were put in a container and refluxed for about 30 minutes to adsorb the dye to the porous semiconductor layer. Thereafter, the substrate was washed with absolute ethanol and dried at about 60 ° C. for about 20 minutes.

On one surface of the second support 7 made of a glass substrate having a thickness of about 1.1 mm, platinum having a thickness of about 300 nm was formed by sputtering as the second conductive layer 6 also serving as the catalyst layer 9.
Through the porous layer 5 made of polyester having a pore radius of 50 nm and a film thickness of 25 μm so that the porous photoelectric conversion layer 3 and the second conductive layer 6 are opposed to the first support 1 and the second support 7. installed. Next, as the carrier transport layer 4, acetonitrile, dimethylpropylimidazolium iodide 0.6 mol / liter, lithium iodide 0.1 mol / liter, iodine 0.1 mol / liter, tertiary butylpyridine 0.5 An electrolytic solution prepared by dissolving so as to have a concentration of mol / liter was infiltrated into the porous photoelectric conversion layer and the porous layer. Furthermore, the side part which made the 1st support body 1 and the 2nd support body 7 face each other was sealed with the sealing material which consists of an epoxy resin, and the solar cell was obtained.

(Solar cell module production example 1)
FIG. 6 is a schematic cross-sectional view showing the layer configuration of the solar cell module of the present invention.
In FIG. 6, 401 is a first support, 409 is a second support, and as unit cell A, 412 is a first conductive layer, 413 is a porous photoelectric conversion layer, 414 is a porous layer, 415 is a catalyst layer, 416 is a second conductive layer, 417 is an insulating layer, and as unit cell B, 422 is a first conductive layer, 423 is a porous photoelectric conversion layer, 424 is a porous layer, 425 is a catalyst layer, 426 second conductive layer, 427 Is an insulating layer.

On one surface of the first support 401 made of a glass substrate having a thickness of about 1.1 mm, SnO ₂ having a thickness of about 900 nm was formed by CVD. The glass substrate and SnO ₂ have a heat resistance of 450 ° C. or higher.
Next, YAG laser light (fundamental wavelength: 1.06 μm) was irradiated onto the deposited SnO ₂ , and only the irradiated portion was evaporated and patterned to form first conductive layers 412 and 422.
Then, the layer used as a porous semiconductor layer was produced in the predetermined position using the titanium oxide paste similarly to the manufacture example of the solar cell unit cell.

  Next, a zirconium oxide paste is applied to a predetermined position on the layer to be a porous semiconductor layer by screen printing, and after leveling, dried in an oven at 80 ° C. and baked in air at 500 ° C. A porous semiconductor layer having a thickness of about 20 μm and porous layers 414 and 424 having a thickness of about 5 μm were formed to be the porous photoelectric conversion layers 413 and 423.

  Specifically, zirconium oxide particles (25 nm in diameter) were added to a surfactant (manufactured by Kishida Chemical Co., Ltd., trade name: Triton-X), glass beads for dispersion (3 mm in diameter), and 100 g of diethylene glycol monomethyl ether per 40 ml of solvent. And the zirconium oxide paste was prepared by dispersing for 2 hours in a paint shaker. The weight mixing ratio was such that the zirconium oxide concentration was 30% and the surfactant concentration was 1%.

When the pore distribution characteristic of the porous layer was measured, the pore radius was 30.2 nm.
Further, when the pore distribution characteristics of the porous semiconductor layer to be the porous photoelectric conversion layers 413 and 423 and the porous layers 414 and 424 were measured at the same time, the pore volume of the fine pore radius distribution characteristics at each pore radius. The peak of change rate ΔVp / Δlog (Rp) became clear. P _T / P _K was 1.91.
Next, in the same manner as in the production example of the solar cell unit cell, the dye was adsorbed on the porous semiconductor layer to obtain porous photoelectric conversion layers 413 and 423.

Platinum having a thickness of about 300 nm was formed as a catalyst layer 415, 425 by sputtering at predetermined positions of the second conductive layers 416, 426 made of SUS304 foil having a thickness of 10 μm.
Next, part of the second conductive layers 416 and 426 is electrically contacted with part of the first conductive layers 412 and 422 using a silver paste, and then an epoxy resin is applied and cured as the insulating layers 417 and 427. I let you.

Next, as a carrier transport layer (not shown), a monomer for forming a polymer electrolyte is injected into the porous photoelectric conversion layers 413 and 423 and the porous layers 414 and 424, and heated at 90 ° C. for 2 hours, Polymerized.
As an electrolytic solution in the polymer electrolyte, a mixed solvent of γ-butyrolactone (manufactured by Kishida Chemical Co., Ltd.) and ethylene carbonate (manufactured by Kishida Chemical Co., Ltd. (mixing ratio is γ-butyrolactone: ethylene carbonate = 7: 3 (volume ratio)) Then, dimethylpropylimidazolium iodide 0.6 mol / liter, lithium iodide 0.1 mol / liter, and iodine 0.1 mol / liter were dissolved.
As the polymer material, a compound prepared by the following synthesis method 1 was used as compound A, and diethyltoluenediamine was used as compound B (mixing ratio was compound A: compound B = 13: 1 (weight ratio)).

(Synthesis method 1)
To 100 parts by weight of polytetramethylene glycol (trade name PTMG2000, manufactured by Mitsubishi Kasei Kogyo Co., Ltd.) in a reaction vessel, 18 parts by weight of tolylene diisocyanate and 0.05 parts by weight of dibutyltin dilaurate as a catalyst were added, at 80 ° C. Reaction was performed to obtain Compound A having a molecular weight of 2350.

  Thereafter, the catalyst layers 415 and 425 and the porous layers 414 and 424 are bent so that they face each other, and then a PET (polyethylene terephthalate) -aluminum-PET film as a second support 409 is laminated with EVA (ethylene- A solar cell module was obtained by laminating at about 100 ° C. using a vinyl acetate copolymer sheet.

(Solar cell module production example 2)
FIG. 7 is a schematic cross-sectional view showing the layer configuration of the solar cell module of the present invention.
In FIG. 7, 501 is a first support, 507 is an insulating layer, 508 is a second conductive layer (second conductor), 509 is a second support, unit cell C 512 is the first conductive layer, 513 is a porous photoelectric conversion layer, 514 is a porous layer, 515 is a catalyst layer, and as unit cell D, 522 is a first conductive layer, 523 is a porous photoelectric conversion layer, 524 is a porous layer, and 525 is a catalyst layer.

A solar cell module having the light receiving surface on the first support 501 and the first conductive layers 512 and 522 side was produced.
In the same manner as in Production Example 1 of the solar cell module, SnO ₂ having a thickness of about 900 nm was formed by CVD on one surface of the first support 501 made of a glass substrate having a thickness of about 1.1 mm. The glass substrate and SnO ₂ have a heat resistance of 450 ° C. or higher.
Next, the deposited SnO ₂ was irradiated with a YAG laser or the like, and only the irradiated portion was evaporated and patterned to form first conductive layers 512 and 522.

In the same manner as in Solar Cell Module Production Example 1, platinum having a thickness of about 300 nm was deposited as a catalyst layer 515 by sputtering on a predetermined position of the second conductive layer 508 made of SUS304 foil having a thickness of 50 μm.
A platinum catalyst paste (manufactured by Solaronix, Pt-Catalyst T / SP) was printed on a predetermined position of the first support 501 on which the first conductive layers 512 and 522 were formed, and a catalyst layer 525 was obtained.

  Next, in the same manner as in Production Example 1 of the solar cell module, after a layer that becomes a porous semiconductor layer is formed at a predetermined position of the first conductive layer 512 and the second conductive layer 508 using a titanium oxide paste, A layer to be a porous layer is applied using a zirconium oxide paste, and after leveling, dried in an oven at 80 ° C. and baked in air at 500 ° C. to become porous photoelectric conversion layers 513 and 523. A porous semiconductor layer having a thickness of about 20 μm and porous layers 514 and 524 having a thickness of about 5 μm were prepared.

Next, an epoxy resin was applied as the insulating layer 507 and cured, and then the dye was adsorbed to the porous semiconductor layers to be the porous photoelectric conversion layers 513 and 523 in the same manner as in Production Example 1 of the solar cell module.
Next, the catalyst layers 515 and 525 and the porous layers 514 and 524 are installed so as to face each other, and a polymer electrolyte is formed as a carrier transport layer (not shown) in the same manner as in Production Example 1 of the solar cell module. The monomer was injected into the porous photoelectric conversion layers 513 and 523 and the porous layers 514 and 524 and heated at 90 ° C. for 2 hours to polymerize the monomers.
A solar cell module was obtained by laminating a film in which PET-aluminum-PET was laminated as the second support 509 at about 100 ° C. using an EVA sheet.

Example 1
Based on the production example of the solar cell unit cell, a solar cell (unit cell) using the porous layer of the present invention shown in FIG. 1 was produced.
As the first support 1 with the first conductive layer 2, a glass substrate (manufactured by Nippon Sheet Glass Co.) with SnO ₂ (fluorine-doped tin oxide) of 20 mm × 45 mm × 4 mm is used, and a porous semiconductor layer is used with a titanium oxide paste. The size was 5 mm × 30 mm, and the film thickness after firing was 20 μm. The capillary force ratio was 1.06.
As a result of examining the operating characteristics of the manufactured solar cell unit cell under AM1.5 simulated sunlight irradiation, the short-circuit current density is 14.2 mA / cm ² , the open-circuit voltage value is 0.680 V, the FF 0.670, the module conversion efficiency is 6. It was 47%.
The obtained results are shown in Table 3.

(Example 2)
A solar cell (unit cell) was produced in the same manner as in Example 1 except that the film thickness after firing of the porous semiconductor layer was 5 μm. The capillary force ratio was 1.91.
As a result of examining the operating characteristics of the manufactured solar cell unit cell under irradiation of AM1.5 simulated sunlight, the short-circuit current density was 14.5 mA / cm ² , the open-circuit voltage value was 0.675 V, FF 0.656, the module conversion efficiency was 6. 42%.
The obtained results are shown in Table 3.

(Example 3)
A solar cell (unit cell) was produced in the same manner as in Example 2 except that the porous layer was produced using a mixed paste of zirconium oxide and silicon oxide (volume ratio 1: 1). The capillary force ratio was 1.15.
As a result of examining the operating characteristics of the manufactured solar cell unit cell under AM1.5 simulated sunlight irradiation, the short-circuit current density was 14.4 mA / cm ² , the open-circuit voltage value was 0.683 V, the FF 0.671, the module conversion efficiency. 60%.
The obtained results are shown in Table 3.
From the obtained results, it can be seen that FF and conversion efficiency are improved by mixing silicon oxide having a higher conduction band level than zirconium oxide in the porous layer.

Example 4
Based on the solar cell unit cell production example 1, an integrated solar cell module of the present invention in which five unit cells shown in FIG. 8 were connected in series was produced.
As the first support 61 with the first conductive layer, a 57 mm × 70 mm × 4 mm glass substrate with SnO ₂ (fluorine-doped tin oxide) (manufactured by Nippon Sheet Glass Co., Ltd.) was used.
In this SnO ₂ , YAG laser light (fundamental wavelength: 1.06 μm) is irradiated to the position where a titanium oxide porous photoelectric conversion layer to be described later is to be produced and a 0.5 mm interval, and only the irradiated portion 64 is evaporated and patterned. did.

  Next, in the same manner as in the production example of the solar cell unit cell, a titanium oxide paste was formed into a film with a size of 5 mm × 50 mm by screen printing, leveled at room temperature for 30 minutes, and then fired at 500 ° C. in air. As a result, a porous semiconductor layer to be a porous photoelectric conversion layer having a thickness of 20 μm was obtained. The printing position was such that the edge of the first support and the edge of the porous photoelectric conversion layer were 10 mm, and the distance between each porous photoelectric conversion layer was 3 mm.

On the other hand, a catalyst layer made of platinum having a film thickness of about 300 nm was formed by sputtering on a second conductive layer made of SUS304 foil of 7.5 mm × 50 mm × 50 μm, and 1 mm × 50 mm at the end thereof was folded. The portion 63 was adhered using a silver paste, and an epoxy resin was applied between the porous photoelectric conversion layer and the second conductive layer (corresponding to the insulating layers 417 and 427 in FIG. 3) with a dispenser and cured.
In the same manner as in the production example of the solar cell unit cell, after the dye is adsorbed to the porous semiconductor layer, the porous layer shown in the production example of the solar cell unit cell is processed into a size of 5 mm × 50 mm, Installed on top of the conversion layer. The capillary force ratio was 1.06.

Thereafter, as a carrier transport layer, a monomer for forming a polymer electrolyte was injected into the whole and polymerized at 90 ° C. for 2 hours.
After the platinum as the catalyst layer is bent so as to face the porous layer, a film in which PET-aluminum-PET is laminated as a second support is laminated at about 100 ° C. by using an EVA sheet to form a solar cell Got a module.
As a result of examining the operating characteristics under irradiation of AM1.5 simulated sunlight for the produced solar cell unit cell, the short-circuit current density is 13.5 mA / cm ² in terms of the unit cell, the open-circuit voltage value is 0.678 V, FF 0.650, The module conversion efficiency was 5.95% (effective area standard).
The obtained results are shown in Table 3.

(Example 5)
A solar cell module was produced based on Example 4 except that the porous layer shown in Example 3 was used. The capillary force ratio was 1.15.
As a result of examining the operating characteristics of the manufactured solar cell unit cell under irradiation of AM1.5 simulated sunlight, the short-circuit current density is 13.8 mA / cm ² in terms of the unit cell, the open-circuit voltage value is 0.681 V, FF 0.655, The module conversion efficiency was 6.16% (effective area standard).
The obtained results are shown in Table 3.

(Example 6)
Based on the solar cell unit cell production example 2, an integrated solar cell module of the present invention in which five unit cells shown in FIG. 9 were connected in series was produced.
As the first conductive layer with the first support member 71a, with 57 mm × 70 mm × 4 mm of SnO ₂ (fluorine-doped tin oxide) coated glass substrate (manufactured by Nippon Sheet Glass Co., Ltd.).
In this SnO ₂ , YAG laser light (fundamental wavelength: 1.06 μm) is irradiated to a position at a distance of 0.5 mm from a position 72a for producing a titanium oxide porous photoelectric conversion layer, which will be described later, and only the irradiated portion 74 is evaporated to perform patterning. did.

  Next, in the same manner as in the production example of the solar cell unit cell, a titanium oxide paste was formed into a film with a size of 5 mm × 50 mm by screen printing, leveled at room temperature for 30 minutes, and then dried in an oven at 80 ° C. I let you. A porous photoelectric conversion layer having a film thickness of 20 μm is formed thereon by forming a film by screen printing using the same material as in Example 3, performing leveling at room temperature for 30 minutes, and firing in air at 500 ° C. A porous semiconductor layer and a porous layer having a thickness of 5 μm were obtained. The printing position was such that the edge of the first support and the edge of the porous photoelectric conversion layer were 10 mm, and the distance between each porous photoelectric conversion layer was 3 mm. The capillary force ratio was 1.15.

On the other hand, on the 72b portion of the second conductive layer 71b made of SUS304 foil of 15 mm × 50 mm × 50 μm, a titanium oxide paste was formed into a size of 5 mm × 50 mm by screen printing, and leveling was performed for 30 minutes at room temperature. It was dried in an oven at 80 ° C. On top of that, a film was formed by screen printing using the same material as in Example 3, leveled at room temperature for 30 minutes, and then dried in an oven at 80 ° C.
Thereafter, a platinum catalyst paste (Solaronix, Pt-Catalyst T / SP) having a size of 5 mm × 50 mm is formed on the 73b portion by screen printing, and baked in air at 500 ° C., thereby performing porous photoelectric conversion. A layer, a porous layer, and a catalyst layer were prepared. By repeating the same process, a total of two substrates were produced.

In the same manner as in the production example of the solar cell unit cell, after the dye is adsorbed to the porous semiconductor layer, the porous photoelectric conversion layer 72a in FIG. 9 (a) and the catalyst layer in FIG. 9 (b) 73b face each other. As a carrier transport layer, a monomer for forming a polymer electrolyte is injected into the whole, and a film in which PET-aluminum-PET is laminated as a second support is formed at about 90 ° C. using an EVA sheet. By laminating for a time, the polymerization of the monomer for forming the polymer electrolyte and the lamination of the second support were performed at the same time, thereby obtaining a solar cell module.
About the produced solar cell unit cell, as a result of investigating the operating characteristics under AM1.5 simulated sunlight irradiation, the short-circuit current density is 13.2 mA / cm ² in terms of the structural unit cell, the open-circuit voltage value is 0.682 V, FF 0.650, The module conversion efficiency was 5.85% (effective area standard).
The obtained results are shown in Table 3.

It is a schematic sectional drawing which shows the layer structure of the solar cell of this invention. It is a figure which shows the pore distribution characteristic of a porous photoelectric converting layer. It is a figure which shows the relationship between the capillary force ratio of a porous layer and a porous photoelectric converting layer, conversion efficiency, and FF. It is a figure which showed the pore distribution characteristic of the porous photoelectric converting layer. It is a figure which shows the relationship between the pore radius of the porous photoelectric converting layer of the solar cell using the porous layer of this invention, and conversion efficiency.

It is a schematic sectional drawing which shows the layer structure of the solar cell module of this invention. It is a schematic sectional drawing which shows the layer structure of the solar cell module of this invention. It is a schematic plan view which shows the support body of the solar cell module of this invention. It is a schematic plan view which shows the support body of the solar cell module of this invention.

Explanation of symbols

1, 61, 71a, 71b, 401, 501 First support 2, 412, 422, 512, 522 First conductive layer 3, 413, 423, 513, 523 Porous photoelectric conversion layer 4 Carrier transport layer 5, 414, 424, 514, 524 Porous layer 6, 416, 426, 508 Second conductive layer 7, 409, 509 Second support 8 Sealant 9, 73a, 73b, 415, 425, 515, 525 Catalyst layer 62, 72a, 72b Position for Producing Porous Photoelectric Conversion Layer 63 Attached Part of Second Conductive Layer 64, 74 Irradiated Part of Laser Light 417, 427, 507 Insulating Layer A, B, C, D Unit Cell

Claims (5)

Between the first support and the second support, at least one of which is made of a light transmissive material, a first conductive layer provided on the first support, and a porous material in which a dye is adsorbed on the porous semiconductor layer A photoelectric conversion layer, a carrier transport layer made of a liquid or gel electrolyte, and a second conductive layer provided in contact with the second support, further comprising a porous layer between the porous photoelectric conversion layer and the second conductive layer And the porous semiconductor layer and the porous layer have a capillary force P _T [Pa] against the liquid or gel electrolyte of the porous layer represented by the following formula :
P _T = 2σ · cos θ _T / r _T
(Where σ is the surface tension [N / m] of the liquid or gel electrolyte , θ _T is the contact angle [°] between the liquid or gel electrolyte and the porous layer material, and r _T is the pore of the porous layer. Radius [m])
And the capillary force P _K [Pa] for the liquid or gel electrolyte of the porous photoelectric conversion layer represented by the following formula :
P _K = 2σ · cos θ _K / r _K
(In the formula, σ is the surface tension [N / m] of the liquid or gel electrolyte , θ _K is the contact angle [°] between the liquid or gel electrolyte and the porous photoelectric conversion layer material, and r _K is porous. It is the pore radius [m] of the photoelectric conversion layer)
A dye-sensitized solar cell, characterized in that the ratio (P _T / P _K ) is a combination of layers in a range of 0.2 to 5 . Porous radius distribution characteristics of the porous photoelectric conversion layer represented by the following formula:
R = ΔV _K / Δlog (R _K ) [mm ³ / nm · g]
(Wherein R _K is the pore radius [nm] of the porous photoelectric conversion layer, ΔV _K is the pore volume per unit weight, and Δlog (R _K ) is the change in the pore radius)
The dye-sensitized solar cell according to claim 1, wherein the peak Rp of the pore volume change rate R in the layer is in a range of 20 to 60 nm. Between the first support and the second support, at least one of which is made of a light transmissive material, a first conductive layer provided on the first support, and a porous material in which a dye is adsorbed on the porous semiconductor layer A photoelectric conversion layer, a carrier transport layer made of a liquid or gel electrolyte, and a second conductive layer provided in contact with the second support, further comprising a porous layer between the porous photoelectric conversion layer and the second conductive layer And the porous semiconductor layer and the porous layer have a capillary force P _T [Pa] against the liquid or gel electrolyte of the porous layer represented by the following formula :
P _T = 2σ · cos θ _T / r _T
(Where σ is the surface tension [N / m] of the liquid or gel electrolyte , θ _T is the contact angle [°] between the liquid or gel electrolyte and the porous layer material, and r _T is the pore of the porous layer. Radius [m])
And the capillary force P _K [Pa] for the liquid or gel electrolyte of the porous photoelectric conversion layer represented by the following formula :
P _K = 2σ · cos θ _K / r _K
(In the formula, σ is the surface tension [N / m] of the liquid or gel electrolyte , θ _K is the contact angle [°] between the liquid or gel electrolyte and the porous photoelectric conversion layer material, and r _K is porous. It is the pore radius [m] of the photoelectric conversion layer)
And at least two or more of the dye-sensitized solar cells according to claim 1 or 2 , which are a combination of layers having a ratio (P _T / P _K ) in the range of 0.2 to 5 , A dye-sensitized solar cell module characterized by being integrated. The first conductive layer on the first support of the dye-sensitized solar cell is electrically connected to the second conductive layer on the second support of another dye-sensitized solar cell adjacent thereto. The dye-sensitized solar cell module according to claim 3 . The first conductive layer on the first support of the dye-sensitized solar cell and the second conductive layer on the first support of another dye-sensitized solar cell adjacent thereto are configured as the same layer. The dye-sensitized solar cell module according to claim 3 .

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