JP5284296B2 - Dye-sensitized solar cell - Google Patents

Description

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

  Dye-sensitized solar cells were developed by Gretzel of Switzerland and have advantages such as high photoelectric conversion efficiency and low manufacturing costs, and are attracting attention as new types of solar cells (for example, patents) Reference 1, Non-Patent Document 1, Japanese Patent Application No. 2001-400593, etc.).

  8A and 8B show an example of a conventional dye-sensitized solar cell. The dye-sensitized solar cell includes a working electrode 3 having an oxide semiconductor porous film 2 made of oxide semiconductor fine particles such as titanium oxide and carrying a photosensitizing dye on an electrode substrate 1, and the working electrode 3. And a counter electrode 4 provided to face each other. An electrolyte layer 5 is formed between the working electrode 3 and the counter electrode 4 by being filled with an electrolytic solution.

The electrode substrate 1 is formed by forming a transparent conductive layer 11 made of tin-added indium oxide (ITO), fluorine-added tin oxide (FTO) or the like on a base material 10 such as a glass plate. Further, in order to improve the current collection efficiency from the oxide semiconductor porous film 2, a grid-like metal wiring layer 12 made of gold, platinum, silver or the like is provided on the transparent conductive layer 11. Furthermore, the surface of the metal wiring layer 12 or the transparent conductive layer 11 is made of ITO, in order to suppress inconveniences such as corrosion of the metal wiring layer 12, short circuit with the electrolyte layer 5, output decrease due to leakage current (reverse electron transfer), etc. It is covered with a shielding layer 13 made of an oxide semiconductor such as FTO, titanium oxide, or zinc oxide.
Further, instead of the electrolyte layer 5, a solid charge transport layer 6 made of a p-type semiconductor or the like may be used.
In this dye-sensitized solar cell, an electromotive force is generated between the working electrode 3 and the counter electrode 4 when light such as sunlight enters from the substrate 10 side.

Japanese Patent Laid-Open No. 01-220380

M. Graetzel et al., Nature, (UK), 1991, No. 737, p. 353

The shielding layer 13 can be formed by forming a film made of an oxide semiconductor on the metal wiring layer 12 by using a thin film forming method such as sputtering or spray pyrolysis (SPD). However, since the surfaces of the transparent conductive layer 11 and the metal wiring layer 12 have fine irregularities (profiles) such as voids, cracks, and grain boundaries, it is difficult to form the dense shielding layer 13 uniformly. The formation failure of the layer 13 may cause an uncovered portion where the metal wiring layer 12 is exposed. In this case, the effect of suppressing inconveniences such as corrosion of the metal wiring layer 12 and reduction in output due to generation of leakage current due to reverse electron transfer from the metal wiring layer 12 to the electrolyte layer 5 or the like is reduced. ) May be significantly impaired.
If the coating thickness of the shielding layer 13 is increased in order to suppress the formation failure of the shielding layer 13, there is a possibility that the photoelectron movement is inhibited or the photoelectric conversion efficiency is lowered due to a decrease in light transmittance.

  For example, when the metal wiring layer 12 is formed using a conductive paste mainly composed of conductive particles such as metal fine particles and a binder such as glass frit, from the viewpoint of the conductivity of the metal wiring layer 12. Although it is better that the blending ratio of the binder is small, fine and steep irregularities such as voids and pinholes and shadows are likely to be formed in or on the metal wiring layer 12, and it is difficult to form a shielding layer. When the blending ratio of the binder is increased, the conductivity of the metal wiring layer 12 is lowered, so that the current collection efficiency is lowered and the cell characteristics may be remarkably impaired.

Further, when the electrode substrate 1 is not provided with the metal wiring layer 12 and current collection from the oxide semiconductor porous film 2 is performed only by the transparent conductive layer 11, the specific resistance of a semiconductor such as FTO constituting the transparent conductive layer 11 is reduced. Since it is about 10 ⁻⁴ to 10 ⁻³ Ω · cm, which is 100 times or more that of metals such as gold and silver, particularly in the case of a large-area cell, the photoelectric conversion efficiency is significantly reduced. If the thickness of the transparent conductive layer 11 is increased in order to reduce the resistance of the transparent conductive layer 11, the light transmittance of the transparent conductive layer 11 is remarkably lowered, and the photoelectric conversion efficiency is also lowered.
The present invention has been made in view of the above circumstances, and in an electrode substrate having a metal wiring layer and a transparent conductive layer, suppresses deterioration of characteristics due to corrosion of the metal wiring layer or leakage current from the metal wiring layer. Is an issue.

In order to solve the above problems, the present invention provides an electrode substrate, an oxide semiconductor porous film carrying a sensitizing dye formed on the surface of the electrode substrate, and a counter electrode provided facing the electrode substrate. A dye-sensitized solar cell comprising an electrolyte layer using an electrolyte containing an oxidation-reduction pair and an organic solvent , wherein the counter electrode is a conductive oxide semiconductor on the substrate and the substrate The electrode substrate has a metal wiring layer and a transparent conductive layer electrically connected to the metal wiring layer on a base material. Provided is a dye-sensitized solar cell , wherein the metal wiring layer is formed on the transparent conductive layer, and the metal wiring layer is covered with an insulating layer.
According to such an electrode substrate, the metal wiring layer is reliably shielded from the electrolyte solution and the like, and corrosion and leakage current can be effectively suppressed. Therefore, the electrode substrate is excellent in conductivity. Thereby, the fall of the output by the corrosion of the metal wiring layer of an electrode substrate, leakage current, etc. can be suppressed, and a dye-sensitized solar cell with high photoelectric conversion efficiency can be obtained.
The insulating layer is preferably formed from a material containing a glass component, and particularly preferably formed by printing a paste containing glass frit. As a result, an insulating layer capable of reliably insulating and shielding the metal wiring layer can be easily formed.
The metal wiring layer is preferably formed by a printing method. Thereby, a metal wiring layer having a desired pattern can be easily formed.

  As described above, the electrode substrate of the present invention has a metal wiring layer and a transparent conductive layer electrically connected to the metal wiring layer on the base material, and the metal wiring layer is insulated by the insulating layer. Since it is covered, the metal wiring layer is reliably shielded from the electrolyte solution and the like, and its corrosion and leakage current can be effectively suppressed. Moreover, compared with the case where only a transparent conductive layer is used as an electrode conductor, the resistance can be lowered and an electrode substrate excellent in conductivity can be obtained.

  When such an electrode substrate is used for a photoelectric conversion element, the electrons passing through the oxide semiconductor porous film are collected through the transparent conductive layer, and further the current collection efficiency is improved by the metal wiring layer. Can do. For this reason, it is possible to reduce the resistance of the electrode substrate and to suppress inconveniences such as deterioration of quality due to corrosion of the metal wiring layer, output reduction due to leakage current, etc. For example, when an insulating layer is not provided As compared with the above, for example, even in a large area cell of 100 mm square class, the photoelectric conversion efficiency can be greatly improved.

It is sectional drawing which shows an example of (a) photoelectric conversion element of this invention, and (b) electrode substrate. It is a fragmentary top view which shows an example of schematic shape of a metal wiring layer. It is sectional drawing which shows 2nd Embodiment of the electrode substrate of this invention. It is sectional drawing which shows 3rd Embodiment of the electrode substrate of this invention. It is sectional drawing which shows 4th Embodiment of the electrode substrate of this invention. It is sectional drawing which shows 5th Embodiment of the electrode substrate of this invention. It is sectional drawing which shows 6th Embodiment of the electrode substrate of this invention. It is sectional drawing which shows an example of the conventional photoelectric conversion element.

Hereinafter, the present invention will be described in detail based on embodiments. Fig.1 (a) is sectional drawing which shows an example of the photoelectric conversion element of this invention, FIG.1 (b) is sectional drawing which shows the electrode substrate 1 used for this photoelectric conversion element.
In FIG. 1, the same reference numerals as those used in FIG. 8 mean the same configurations as those in FIG. In this photoelectric conversion element, an electromotive force is generated between the working electrode 3 and the counter electrode 4 when light such as sunlight enters from the substrate 10 side due to the same effect as that of the conventional device, thereby obtaining electric power. A dye-sensitized solar cell.
The photoelectric conversion element of the present embodiment is different from the conventional one in that, as shown in FIG. 1B, the electrode substrate 1 is formed on a base material 10 with a transparent conductive layer 11 and the transparent conductive layer 11. The metal wiring layer 12 formed above and an insulating layer 14 covering the surface of the metal wiring layer 12 are provided, and the metal wiring layer 12 is covered with the insulating layer 14. .

  As a material of the base material 10, a material having high light transmittance is preferable for use. Besides glass, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyethersulfone (PES), and the like. A transparent plastic sheet, a polishing plate made of ceramics such as titanium oxide, and alumina can be used.

The transparent conductive layer 11 is formed on the substrate 10 over a region wider than the region where the metal wiring layer 12 is formed, and the material thereof is not particularly limited. For example, tin-doped indium oxide ( Examples thereof include conductive metal oxides such as ITO), tin oxide (SnO ₂ ), and fluorine-added tin oxide (FTO).
As a method for forming the transparent conductive layer 11, a known appropriate method according to the material of the transparent conductive layer 11 may be used. Examples thereof include a sputtering method, a vapor deposition method, an SPD method, and a CVD method. In consideration of light transmittance and conductivity, the film is usually formed to a thickness of about 0.001 μm to 10 μm.

  The metal wiring layer 12 is formed by wiring a metal such as gold, silver, platinum, aluminum, nickel, titanium or the like in a pattern such as a grid, stripe, or comb as shown in FIG. In order not to significantly impair the light transmittance of the electrode substrate 1, it is preferable that the width of each wiring is as thin as 1000 μm or less. The thickness (height) of each wiring of the metal wiring layer 12 is not particularly limited, but is preferably 0.1 to 10 μm.

As a method for forming the metal wiring layer 12, for example, a metal powder that becomes conductive particles and a binder such as glass fine particles are mixed to form a paste, and this is a printing method such as a screen printing method, a metal mask method, or an inkjet method. There is a method in which a coating film is formed so as to form a predetermined pattern using, and the conductive particles are fused by heating and baking. As the firing temperature, for example, when the substrate 10 is glass, it is preferably 600 ° C. or lower, more preferably 550 ° C. or lower. In addition, a forming method such as a sputtering method, a vapor deposition method, or a plating method can also be used.
From the viewpoint of conductivity, the volume resistivity of the metal wiring layer 12 is preferably 10 ⁻⁵ Ω · cm or less. The surface of the metal wiring layer 12 is preferably smooth, but there may be some unevenness or unevenness.

  The insulating layer 14 is formed by using one or a plurality of insulating materials such as resin, ceramics, glass, and the like, and depositing one or more layers on the region where the metal wiring layer 12 is formed. be able to. The region where the insulating layer 14 is formed may protrude from the periphery of the pattern of the metal wiring layer 12 as long as the incidence of light and charge transfer to the transparent conductive layer 11 are not so hindered.

  The method for forming the insulating layer 14 is not necessarily limited, but a screen printing method using a glass paste obtained by blending a glass frit with an appropriate thickener, binder, dispersant, solvent, and the like. A method of coating a film so as to overlap the pattern of the metal wiring layer 12 by a printing method such as a metal mask method or an ink jet method, and heating and baking is preferable from the viewpoints of ease of pattern formation and cost. The firing temperature is preferably 600 ° C. or lower, more preferably 550 ° C. or lower. Glass that can be fired at such temperatures includes amorphous lead-based solder glass such as lead oxide, lead borate, and lead bismuth borate, as well as non-lead or amorphous glass. Solder glass or the like can be used. The number of layers of the insulating layer 14 may be one layer or a plurality of layers. In the case of a plurality of layers, one type of glass paste may be formed twice or more, or two or more types having different melting temperatures. A glass paste of may be used.

  An oxide semiconductor porous film 2 carrying a sensitizing dye is formed on the surface of the electrode substrate 1 manufactured as described above. The electrode substrate 1 and the oxide semiconductor porous film 2 are used to A working electrode 3 of the conversion element is configured.

The oxide semiconductor porous film 2 is one or two of titanium oxide (TiO ₂ ), tin oxide (SnO ₂ ), tungsten oxide (WO ₃ ), zinc oxide (ZnO), niobium oxide (Nb ₂ O ₅ ), and the like. This is a porous thin film made of oxide semiconductor fine particles having an average particle diameter of 1 to 1000 nm and having a thickness of about 0.5 to 50 μm.

  In order to form the oxide semiconductor porous membrane 2, for example, a dispersion in which commercially available oxide semiconductor fine particles are dispersed in a desired dispersion medium or a colloid solution that can be adjusted by a sol-gel method is used as necessary. After adding a desired additive, the electrode substrate 1 is immersed in a colloidal solution in addition to coating by a known application such as a screen printing method, an ink jet printing method, a roll coating method, a doctor blade method, a spin coating method, or a spray coating method. Electrophoretic electrodeposition in which oxide semiconductor fine particles are deposited on the electrode substrate 1 by electrophoresis, a method in which a foaming agent is mixed and applied to a colloidal solution or dispersion, and then sintered and made porous. After mixing and applying the beads, this polymer microbead is removed by heat treatment or chemical treatment to form voids, etc. It is possible to apply.

  The sensitizing dye supported on the oxide semiconductor porous film 2 is not particularly limited. For example, a ruthenium complex or iron complex having a ligand including a bipyridine structure or a terpyridine structure, a porphyrin series, or a phthalocyanine series. From metal complexes, organic dyes such as eosin, rhodamine, merocyanine, etc., they can be appropriately selected and used according to the application and the material of the oxide semiconductor porous film.

  As an electrolytic solution for forming the electrolyte layer 5, an organic solvent containing a redox couple, a room temperature molten salt, or the like can be used. Examples of the organic solvent include acetonitrile, methoxyacetonitrile, propionitrile, ethylene carbonate, propylene carbonate, diethyl carbonate, and γ-butyrolactone. Examples of the room temperature molten salt include salts composed of a quaternized imidazolium cation and an iodide ion or a bistrifluoromethylsulfonylimide anion.

The redox pair contained in the electrolytic solution is not particularly limited, and can be obtained by adding a pair such as iodine / iodide ion or bromine / bromide ion. As a supply source of iodide ion or bromide ion, lithium salt, quaternized imidazolium salt, tetrabutylammonium salt and the like can be used alone or in combination.
Additives such as tert-butylpyridine can be added to the electrolytic solution as necessary. Moreover, you may use what gelatinized with the suitable gelling agent and suppressed fluidity | liquidity.

  Further, instead of the electrolyte layer 5, a solid charge transfer layer 6 made of a p-type semiconductor or the like can also be used. As the p-type semiconductor, for example, a monovalent copper compound such as copper iodide or copper thiocyanide can be suitably used. A method for forming the charge transfer layer 6 is not particularly limited, and a known method can be applied. Examples thereof include a casting method, a sputtering method, and a vapor deposition method. In addition, the charge transport layer 6 may contain an additive as required for layer formation.

  As the counter electrode 4, for example, a thin film made of a conductive oxide semiconductor such as ITO or FTO is formed on a substrate made of a nonconductive material such as glass, or a gold, platinum, or carbon-based material is formed on the substrate. A material in which an electrode is formed by vapor deposition or application of a conductive material such as a material can be used. Alternatively, a layer of platinum, carbon, or the like may be formed on a thin film of a conductive oxide semiconductor such as ITO or FTO.

Examples of a method for producing such a counter electrode 4 include a method of forming a platinum layer by performing a heat treatment after applying chloroplatinic acid. Alternatively, the electrode may be formed on the substrate by vapor deposition or sputtering.
When the charge transport layer 6 is used instead of the electrolyte layer 5, a method is used in which a conductive material to be the electrode of the counter electrode 4 is directly formed on the charge transport layer 6 by a method such as sputtering or coating. You can also.

  According to the electrode substrate of the present embodiment, since the transparent conductive layer 11 and the metal wiring layer 12 are in contact and electrically connected, electrons from the oxide semiconductor porous film 2 are transferred to the transparent conductive layer. 11 and current collection efficiency can be increased through the metal wiring layer 12. Further, the metal wiring layer 12 is reliably shielded from the solution of the electrolyte layer 5 and the like, and the corrosion and leakage current can be effectively suppressed. Therefore, since it can be set as the electrode substrate 1 which is excellent in an electroconductive characteristic, the contact of the metal wiring layer 12 and the electrolyte layer 5 is comprised by comprising the working electrode of a photoelectric conversion element using the electrode substrate of this Embodiment. Can be prevented, corrosion and a decrease in output due to leakage current can be suppressed, and a photoelectric conversion element with high photoelectric conversion efficiency can be manufactured.

FIG. 3 is a schematic cross-sectional view showing a second embodiment of the electrode substrate of the present invention. In the electrode substrate 1 of this example, the metal wiring layer 12 is provided on the base material 10, and the transparent conductive layer 11 straddles the metal wiring layer 12 and is a region where the metal wiring layer 12 is formed. It is formed over a wider area. The insulating layer 14 is formed on the transparent conductive layer 11 so as to overlap the pattern of the metal wiring layer 12 so as to cover the upper surface and side surfaces of the metal wiring layer 12. That is, the insulating layer 14 is provided on the metal wiring layer 12 via the transparent conductive layer 11.
According to such an electrode substrate 1, since the metal wiring layer 12 can be insulated and shielded by the insulating layer 14, similarly to the electrode substrate 1 of the first embodiment, the occurrence of leakage current is suppressed, It can be set as the electrode substrate 1 which is excellent in an electroconductive characteristic. Moreover, even if this electrode substrate 1 is used, a photoelectric conversion element with high photoelectric conversion efficiency can be manufactured.

Another embodiment of the electrode substrate of the present invention is shown.
As shown in FIG. 4, in the electrode substrate of the third embodiment, a transparent conductive layer 11 is formed on a base material 10, and a metal wiring is formed on the transparent conductive layer 11 as a pattern such as a lattice pattern. Layer 12 is formed. A shielding layer 13 made of an oxide semiconductor thin film is provided on the transparent conductive layer 11, and an insulating layer 14 is formed on the metal wiring layer 12.
Further, as shown in FIG. 5, the electrode substrate of the fourth embodiment has a metal wiring layer 12 formed on the base material 10 as a lattice pattern or the like. In addition, the transparent conductive layer 11 is formed over a region wider than the region where the metal wiring layer 12 is formed. A shielding layer 13 made of an oxide semiconductor thin film is provided on the transparent conductive layer 11. Further, the insulating layer 14 is formed on the shielding layer 13 so as to overlap the pattern of the metal wiring layer 12 so as to cover the upper surface and side surfaces of the metal wiring layer 12.
Although the problem is small as compared with the metal wiring layer 12, since reverse electron transfer from the transparent conductive layer 11 is pointed out, the shielding layer 13 is formed on the transparent conductive layer 11 as shown in FIGS. By providing this, a higher shielding effect can be obtained.

As the material of the shielding layer 13, a compound having a low electron transfer reaction rate with an electrolytic solution containing a redox species and having a high light transmission property and a high photoelectron transfer capability is selected. Titanium oxide, zinc oxide, niobium oxide, Examples include tin oxide, fluorine-added tin oxide (FTO), and tin-added indium oxide (ITO).
The shielding layer 13 needs to be formed so thin that it does not hinder the movement of electrons to the transparent conductive layer 11, and preferably has a thickness of about 10 to 3000 nm. Examples of the method for forming the shielding layer 13 include a sputtering method, a vapor deposition method, an SPD method, a spin coating method, a dipping method, and a doctor blade method. However, in these methods, the denseness of the shielding layer 13 and the adaptability to the surface shape of the substrate 10 are not necessarily sufficient, and it is difficult to obtain sufficient shielding performance of the metal wiring layer 12. For this reason, even when the shielding layer 13 is formed, it is necessary to form the insulating layer 14 directly on the metal wiring layer 12 or via the transparent conductive layer 11 or the shielding layer 13. Thereby, the insulation shielding of the metal wiring layer 12 can be sufficiently performed.

The method for forming the shielding layer 13 is not particularly limited, and for example, an oxide semiconductor as a target compound or a precursor thereof is formed by a dry method (vapor phase method) such as a sputtering method, a vapor deposition method, or a CVD method. A method is mentioned. For example, when a precursor such as metal is formed, the shielding layer 13 can be obtained by oxidation by heat treatment or chemical treatment.
In the case of the wet method, a liquid containing the target compound or its precursor is applied by a method such as spin coating, dipping, or blade coating, and then chemically changed to the target compound by heat treatment or chemical treatment. The shielding layer 13 can be obtained. Examples of the precursor include salts and complexes having a constituent metal element of the target compound. In order to obtain a dense film, a solution is more preferable than a dispersion.
As another method for forming the shielding layer 13, for example, using a spray pyrolysis method (SPD), the substrate 10 having the transparent conductive layer 11 is heated and the precursor of the shielding layer 13 is directed toward the substrate 10. A method of forming the shielding layer 13 can also be used by spraying a substance that becomes a body and thermally decomposing it into a target oxide semiconductor.
By providing the shielding layer 13 for shielding the transparent conductive layer 11 in this way, reverse electron transfer from the transparent conductive layer 11 can be suppressed, and therefore by using the electrode substrate of the present embodiment. A photoelectric conversion element with high photoelectric conversion efficiency can be manufactured.

In addition, the shielding layer 13 can have an effect as a protective layer for a purpose different from that of the insulating layer 14, for example, as required in characteristics.
For example, FIG. 6 shows an electrode substrate according to a fifth embodiment of the present invention. In the electrode substrate 1, the shielding layer 13 is formed not only on the transparent conductive layer 11 but also on the metal wiring layer 12 and the insulating layer 14. Thereby, the shielding layer 13 can also be used as a protective layer for the metal wiring layer 12 and the insulating layer 14.

Another embodiment of the electrode substrate of this invention is shown. FIG. 7 is a schematic cross-sectional view showing an electrode substrate according to a sixth embodiment of the present invention. In this electrode substrate 1, a metal wiring layer 12 is formed on the first transparent conductive layer 11 a as a wiring pattern such as a lattice shape, a stripe shape, or a comb shape. An insulating layer 14 for covering the metal wiring layer 12 is provided. Further, a second transparent conductive layer 11b is formed across the metal wiring layer 12 and the insulating layer 14. That is, the metal wiring layer 12 and the insulating layer 14 are sandwiched between the first transparent conductive layer 11a and the second transparent conductive layer 11b. The 1st and 2nd transparent conductive layers 11a and 11b are the same as the above-mentioned transparent conductive layer 11, and are thin films which consist of conductive metal oxides, such as ITO and FTO.
According to such an electrode substrate 1, the metal wiring layer 12 can be insulated and shielded by the insulating layer 14, and the metal wiring layer 12 and the insulating layer 14 can be protected by the second transparent conductive layer 11 b. Further, by having the second transparent conductive layer 11b in addition to the first transparent conductive layer 11a, it can be expected to improve the current collection efficiency.

Although the present invention has been described based on the preferred embodiment, the present invention is not limited to this embodiment, and various modifications can be made without departing from the gist of the present invention.
For example, the electrode substrate of the present invention can also be applied to photoelectric conversion elements other than solar cells, such as photochemical cells and optical sensors. Also in this case, since the metal wiring layer 12 of the electrode substrate 1 is covered with the insulating layer 14 and the contact of the electrolyte solution or the like to the metal wiring layer 12 is prevented, inconveniences such as corrosion and short circuit are suppressed, and the quality is improved. Deterioration, photoelectric conversion characteristics, photoresponsiveness, and the like can be suppressed.

Hereinafter, the present invention will be described in detail by way of specific examples.
<Example 1>
[Production of electrode substrate]
As a transparent conductive layer 11 (11a) and a substrate 10, a glass substrate with an FTO film of 100 mm × 100 mm is used, and a silver paste for printing (with a volume resistivity of 3 × 10 ⁻⁶ Ω after sintering) is applied to this surface. ) Was screen-printed in a lattice shape, leveled for 10 minutes, dried in a hot air circulating furnace at 135 ° C. for 20 minutes, and baked at 550 ° C. for 15 minutes to form a metal wiring layer 12 made of a silver circuit. The metal wiring layer 12 had a circuit width of 150 μm and a film thickness of 5 μm.
While aligning using a CCD camera, the glass paste is printed on the metal wiring layer 12 by screen printing, and after leveling for 10 minutes, it is dried in a hot air circulating oven at 135 ° C. for 20 minutes, 550 ° C., The insulating layer 14 was formed by baking for 15 minutes. The width of the obtained insulating layer 14 was 250 μm, and the film thickness from the surface of the glass substrate was 10 μm. Therefore, the insulating layer 14 is formed on the metal wiring layer 12 with a thickness of about 5 μm.
When the surface of the insulating layer 14 was observed with a scanning electron microscope (SEM), the glass frit grains were melted and fused to each other, the surface of the insulating layer 14 was dense, and had defects such as significant pinholes. I found that there was no.
Further, an FTO film serving as the second transparent conductive layer 11b that also serves as the protective layer and the shielding layer 13 is formed by the SPD method so as to straddle the metal wiring layer 12 and the insulating layer 14, and FIG. An electrode substrate 1 having the configuration shown in FIG. 7) was produced.

[Production of photoelectric conversion element]
A dispersed aqueous solution of titanium oxide (average particle size 25 nm) is applied on the obtained electrode substrate 1, dried, and then heat-treated at 450 ° C. for 1 hour, whereby an oxide semiconductor porous film 2 having a thickness of 10 μm. Formed. Furthermore, the working electrode 3 was produced by immersing the dye in an ethanol solution of ruthenium bipyridine complex (N3 dye) for 8 hours to carry the dye.
A platinum sputtered FTO glass electrode substrate is used as the counter electrode 4, and the counter electrode 4 and the working electrode 3 are opposed to each other with a 50 μm-thick thermoplastic polyolefin resin sheet interposed as a spacer, and the resin sheet is thermally melted. Both electrodes 3 and 4 were fixed. At this time, a part of the counter electrode 4 side was left open to serve as an electrolyte injection port. After injecting a methoxyacetonitrile solution containing 0.5M iodide salt and 0.05M iodine as main components from the injection port to form the electrolyte layer 5, the peripheral portion and the injection port are connected to the epoxy system. This was sealed with a sealing resin, and a silver paste was applied to the current collector to produce a photoelectric conversion element serving as a test cell.
When the photoelectric conversion characteristics of this test cell were evaluated with simulated sunlight having an air mass (AM) of 1.5, the conversion efficiency was 3.0%.

<Example 2>
[Production of electrode substrate]
Using a heat-resistant glass substrate of 100 mm × 100 mm as the base material 10, a metal wiring layer 12 having a circuit width of 50 μm and a film thickness of 5 μm is formed on this surface by using the same silver paste for printing as in Example 1. After that, an FTO film to be the transparent conductive layer 11 was formed on the metal wiring layer 12 by the SPD method. Further, using the same method as in Example 1, the insulating layer 14 was formed in accordance with the pattern of the metal wiring layer 12 by printing a glass paste to produce the electrode substrate 1 having the configuration shown in FIG.
[Production of photoelectric conversion element]
Using this electrode substrate 1, a photoelectric conversion element to be a test cell was produced by the same procedure as in Example 1. When the photoelectric conversion characteristics of this test cell were evaluated with simulated sunlight having an air mass (AM) of 1.5, the conversion efficiency was 2.5%.

<Example 3>
[Production of electrode substrate]
A 100 mm × 100 mm glass substrate with an FTO film was used as the transparent conductive layer 11 and the base material 10, and a metal wiring layer 12 made of a gold circuit having a circuit width of 50 μm and a film thickness of 5 μm was formed on this surface by an additive plating method. . An insulating layer 14 is formed on the metal wiring layer 12 in accordance with the pattern of the metal wiring layer 12 by printing a glass paste using the same method as in the first embodiment, and the structure shown in FIG. An electrode substrate 1 was produced.
[Production of photoelectric conversion element]
Using this electrode substrate 1, a photoelectric conversion element to be a test cell was produced by the same procedure as in Example 1. When the photoelectric conversion characteristics of this test cell were evaluated with simulated sunlight having an air mass (AM) of 1.5, the conversion efficiency was 3.3%.

<Comparative Example 1>
[Production of electrode substrate]
A 100 mm × 100 mm heat-resistant glass substrate was used as the base material 10, and a metal wiring layer 12 having a circuit width of 100 μm and a film thickness of 5 μm was formed on the surface using a silver paste for printing using the same procedure as in Example 1. Thereafter, an FTO film to be the transparent conductive layer 11 and the shielding layer 13 was formed on the metal wiring layer 12 by the same procedure as in Example 2, and the electrode substrate 1 was produced.
[Production of photoelectric conversion element]
Using this electrode substrate 1, a photoelectric conversion element to be a test cell was produced by the same procedure as in Example 1. When the electrolyte injected into the test cell was observed, the one that was brown immediately after the injection was almost transparent after a few minutes. This is probably because I ₃ ⁻ ions in the electrolyte were reduced to I ⁻ by reacting with the exposed silver because the silver circuit was not sufficiently shielded. Moreover, when the photoelectric conversion characteristic of this test cell was evaluated with artificial sunlight having an air mass (AM) of 1.5, the photoelectric conversion efficiency was 0.24%.
From this, it can be seen that when the insulating layer 14 is not provided, the silver circuit is not sufficiently shielded, and the photoelectric conversion efficiency of the photoelectric conversion element tends to decrease.

<Comparative example 2>
[Production of electrode substrate]
A 100 mm × 100 mm glass substrate with an FTO film was used as the transparent conductive layer 11 and the base material 10, and a metal wiring layer 12 made of a gold circuit having a circuit width of 50 μm and a film thickness of 5 μm was formed on this surface by an additive plating method. . On the metal wiring layer 12, an FTO film having a thickness of 300 nm to be the transparent conductive layer 11 and the shielding layer 13 was formed using the same method as in Example 2, and the electrode substrate 1 was manufactured.
When the surface of the electrode substrate 1 formed in this way was observed by SEM and EDX, there was a stagnation that could be attributed to the skirting of the plating resist at the bottom of the metal wiring layer 12. The coating was not formed.
[Production of photoelectric conversion element]
Using this electrode substrate 1, a photoelectric conversion element to be a test cell was produced by the same procedure as in Example 1. When the photoelectric conversion characteristics of this test cell were evaluated with simulated sunlight having an air mass (AM) of 1.5, the conversion efficiency was 0.30%. Therefore, when the insulating layer 14 is not provided and only the shielding layer 13 is provided for shielding the conductive layer, the metal wiring layer 12 is easily exposed, and when the metal wiring layer 12 is exposed, the photoelectric conversion element It can be seen that this is a problem because the photoelectric conversion efficiency of the film may be significantly reduced.

<Comparative Example 3>
[Production of electrode substrate]
As the transparent conductive layer 11 and the base material 10, a glass substrate with an FTO film of 100 mm × 100 mm was used, and the glass substrate with an FTO film itself was used as the electrode substrate 1 without providing the metal wiring layer 12 on this surface. The photoelectric conversion element used as a test cell was produced by the same procedure as 1. When the photoelectric conversion characteristics of this test cell were evaluated with simulated sunlight having an air mass (AM) of 1.5, the conversion efficiency was 0.11%. From this, it can be seen that when the metal wiring layer 12 is not provided, the photoelectric conversion efficiency of the photoelectric conversion element is low because the resistance of the electrode substrate 1 is large.

DESCRIPTION OF SYMBOLS 1 ... Electrode substrate, 10 ... Base material, 11 ... Transparent conductive layer, 12 ... Metal wiring layer, 13 ... Shielding layer, 14 ... Insulating layer.

Claims (5)

Formed between an electrode substrate, an oxide semiconductor porous film carrying a sensitizing dye formed on the surface of the electrode substrate, and a counter electrode provided facing the electrode substrate ; A dye-sensitized solar cell including an electrolyte layer using an electrolytic solution containing an organic solvent ,
The counter electrode comprises a substrate and an electrode formed on the substrate by a thin film made of a conductive oxide semiconductor or a layer of a conductive material,
The electrode substrate has a metal wiring layer and a transparent conductive layer electrically connected to the metal wiring layer on a base material, and the metal wiring layer is formed on the transparent conductive layer, A dye-sensitized solar cell, wherein a metal wiring layer is covered with an insulating layer.   The dye-sensitized solar cell according to claim 1, wherein the counter electrode has a layer of a conductive material on the electrode, and the conductive material is gold, platinum, or carbon.   The dye-sensitized solar cell according to claim 1 or 2, wherein the insulating layer is formed of a material containing a glass component.   The dye-sensitized solar cell according to claim 3, wherein the insulating layer is formed by printing a paste containing glass frit.   The dye-sensitized solar cell according to any one of claims 1 to 4, wherein the metal wiring layer is formed by a printing method.

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