JP4416997B2 - Electrode substrate for dye-sensitized solar cell, photoelectric conversion element, and dye-sensitized solar cell - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrode substrate for a dye-sensitized solar cell , a photoelectric conversion element, and a dye-sensitized solar cell.
[0002]
[Prior art]
Against the backdrop of environmental issues and resource issues, solar cells as clean energy are attracting attention. However, conventional silicon-based solar cells still have problems such as high manufacturing costs and insufficient raw material supply, and have not yet been widely spread. In addition, although compound solar cells such as CIS have excellent characteristics such as extremely high conversion efficiency, problems such as cost and environmental load are still obstacles to widespread use.
[0003]
On the other hand, dye-sensitized solar cells are attracting attention as photoelectric conversion elements that are inexpensive and can obtain high conversion efficiency (see, for example, Non-Patent Document 1). As a general structure of this photoelectric conversion element, a semiconductor electrode in which a porous film using oxide semiconductor nanoparticles such as titanium dioxide is formed on a transparent conductive substrate and a sensitizing dye is supported on the porous film. And a counter electrode such as a platinum-sputtered conductive glass, and an organic electrolyte containing an oxidizing / reducing species such as iodine / iodide ions between the two electrodes as a charge transfer layer. It has been reported that the semiconductor electrode has a porous film structure having a large specific surface with a roughness factor> 1000, thereby increasing the light absorption rate and a photoelectric conversion efficiency of 10% or more. In terms of cost, it is expected to be about 1/2 to 1/6 that of current silicon-based solar cells, and does not necessarily require complicated and large-scale manufacturing facilities, and does not contain harmful substances. It can be said that it has high potential as an inexpensive and mass-produced solar cell that can be produced.
[0004]
As the transparent substrate used here, a glass substrate is generally coated with a transparent conductive film such as tin-added indium oxide (ITO) or fluorine-added tin oxide (FTO) in advance by a technique such as vapor deposition or sputtering. However, since the specific resistance of ITO or FTO is about 10 ⁻⁴ to 10 ⁻³ Ω · cm, which is about 100 times the specific resistance of metals such as silver and gold, commercially available transparent conductive glass is resistant. When the value is high and it is used for a solar cell, particularly when it is a large area cell, the photoelectric conversion efficiency is significantly lowered.
As a technique for lowering the resistance of the transparent conductive glass, it is conceivable to increase the formation thickness of the transparent conductive layer (ITO, FTO, etc.), but if the film is formed with a thickness sufficient to obtain a sufficient resistance value, the transparent conductive layer is transparent. The light absorption by the layer is increased, and the window material transmission efficiency of incident light is remarkably lowered. As a result, the photoelectric conversion efficiency of the solar cell is also lowered.
[0005]
As a solution to such problems, for example, a metal wiring layer is provided on the surface of a substrate with a transparent conductive layer used as a window electrode of a solar cell so as not to significantly impair the aperture ratio, and the resistance of the substrate is reduced. (For example, see Japanese Patent Application No. 2001-400593.) In addition, when the metal wiring layer is provided on the substrate surface in this way, at least the metal wiring layer surface portion is prevented in order to prevent corrosion of the metal wiring due to the electrolytic solution and reverse electron transfer from the metal wiring layer to the electrolytic solution. It needs to be protected by some kind of shielding layer. The thickness of the shielding layer is not always required, but the circuit surface must be densely coated.
[0006]
[Patent Document 1]
JP-A-1-220380 [Non-Patent Document 1]
By B. O'Regan, M. Graetzel, nature, vol. 353, Oct. 24, 1991, p737
[0007]
[Problems to be solved by the invention]
However, if there are shadowed parts such as pinholes or cracks on the surface of the metal circuit, parts that are not covered by the shielding layer may occur, which leads to corrosion of the circuit and back-electron transfer to the electrolyte. The characteristics will be significantly impaired. In particular, as a method for forming a film using general FTO, ITO, or titanium oxide as a shielding layer, a sputtering method, a spray pyrolysis method, or the like is preferable. However, it is difficult to form a shadow portion by this method. Further, if the thickness of the shielding layer is increased to correct the defective portion, the light transmittance is impaired, which is also not preferable.
[0008]
For example, in the case of a circuit printed with a paste mainly composed of conductive particles and a glass frit binder and sintered at about 500 ° C., in order to obtain high conductivity without preventing fusion between the conductive particles. In order to reduce the blending amount of the glass frit, generally, sudden irregularities and shadows such as voids and pinholes are generated on the surface and inside of the coating film, and it becomes extremely difficult to form a shielding layer. On the contrary, in order to suppress such defects on the coating film surface, when the blending amount of the glass frit serving as the binder is increased, the coating film conductivity is remarkably lowered and the original function of the circuit tends not to be exhibited. .
[0009]
[Means for Solving the Problems]
The present invention has been made in view of the above circumstances, and provides a technique for reducing the surface roughness (roughness) of a metal wiring layer and forming a dense shielding layer free from pinholes. Here, in particular, attention has been paid to a method of applying a printing method such as screen printing to at least a part of the circuit forming process in order to improve manufacturing cost and manufacturing efficiency.
[0010]
That is, the electrode substrate for a dye-sensitized solar cell of the present invention is an electrode substrate having a metal wiring layer and a transparent conductive layer on a transparent substrate, wherein the metal wiring layer and the transparent conductive layer are overlapped with each other at the overlapping portion. The wiring layer is disposed below or on the transparent conductive layer, the metal wiring layer is composed of at least two layers of an inner layer and an outer layer, and the volume resistivity of the inner layer is smaller than the volume resistivity of the outer layer, and the outer layer Is formed of a paste composition containing at least conductive particles and a binder material, and the binder ratio of the paste composition is equal to the binder ratio in the composition forming the other layers in the metal wiring layer. In comparison, it is characterized by having a shielding layer on the surface of the conductive layer composed of the metal wiring layer and / or the transparent conductive layer .
The outer layer is preferably formed by a printing method .
Moreover, it is preferable that the composition which forms the said metal wiring layer contains silver or nickel .
The photoelectric conversion element of this invention has the above-mentioned electrode substrate for dye-sensitized solar cells, It is characterized by the above-mentioned.
The dye-sensitized solar cell of the present invention comprises the above-described photoelectric conversion element.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The electrode substrate of the present invention is an electrode substrate having a metal wiring layer and a transparent conductive layer on a transparent substrate, and the metal wiring layer is composed of at least two layers of an inner layer and an outer layer. Further, as shown in FIG. 1, the electrode substrate may have a structure in which a metal wiring layer 4 is disposed on a transparent conductive layer 3 formed on one surface of the transparent substrate 2, or as shown in FIG. Alternatively, the transparent conductive layer 3 may be formed on the transparent substrate 2 on which the metal wiring layer 4 is disposed. In FIG. 2, the same reference numerals as those used in FIG. 1 mean the same configurations as those in FIG. 1.
[0012]
As a material for the transparent substrate 2, glass such as heat-resistant glass is generally used. Besides glass, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyether Examples thereof include transparent plastics such as sulfone (PES) and ceramic polishing plates such as titanium oxide and alumina, and those having high light transmittance are preferable.
[0013]
As a material for forming the transparent conductive layer 3 is not particularly limited, for example, indium tin oxide (ITO), tin oxide (SnO _2), etc. can be mentioned fluorine-doped tin oxide (FTO), as much as possible light transmission It is preferable to select a material having a high value according to the combination of materials and applications.
[0014]
As a method for forming the transparent conductive layer 3 on the transparent substrate 2, an appropriate method may be used according to a material for forming the transparent conductive layer 3 from known methods such as a sputtering method and a vapor deposition method.
[0015]
The material for forming the inner layer 4a of the metal wiring layer 4 is not particularly limited, and for example, gold, silver, platinum, aluminum, nickel, titanium, or the like can be used. Among these, silver or nickel can be suitably used because it is relatively inexpensive and easily available as a general-purpose printing paste.
In addition, a binder material or an appropriate additive can be added as long as the characteristics such as conductivity are not impaired.
[0016]
The method for forming the inner layer 4a is not particularly limited, and examples thereof include a printing method, a sputtering method, a vapor deposition method, a plating method, and the like. Among these, the printing method is particularly desirable.
[0017]
The inner layer 4a formed in this way preferably has a smaller volume resistivity than the volume resistivity of the outer layer 4b. In the present invention, the coating layer surface of the inner layer 4a is preferably smooth. However, since this layer is formed according to the original purpose as the metal wiring layer 4 that lowers the resistance of the electrode substrate 1, it may have high conductivity. have priority. On the other hand, the outer layer 4b, which will be described later, is a conductive layer, but its main purpose is to smooth the wiring surface and facilitate the formation of the shielding layer 5, so that the volume resistivity is higher than that of the inner layer 4a. It does not matter if it is large.
The volume resistivity of the inner layer 4a is preferably at least 5 × 10 ⁻⁵ Ω · cm. Under these conditions, even if some pinholes or cracks occur on the surface of the coating film, it can be corrected by the outer layer 4b, so that there is no problem. As long as this layer is included in the metal wiring layer 4, another layer different from the outer layer 4b may be formed inside and outside the inner layer 4a for some purpose.
[0018]
The outer layer 4b of the metal wiring layer 4 is preferably formed of a paste composition containing at least conductive particles and a binder material. The conductive particles are not particularly limited, and examples thereof include silver, nickel, gold, and platinum. Among these, silver or nickel can be suitably used because it is relatively inexpensive and easily available as a general-purpose printing paste.
Although there is no restriction | limiting in particular as binder material, For example, when using as the electrode substrate 1 of a dye-sensitized solar cell, since a heat processing of about 400-500 degreeC is included in a manufacturing process, a paste composition is a baking type. For example, glass frit is desirable. The glass frit used as the binder material is not particularly limited as long as it can be melted at the firing temperature or lower.
[0019]
The blending ratio of the binder material in the paste composition forming the outer layer 4b is preferably larger than the blending ratio of the binder material in the composition forming the other layers in the metal wiring layer 4. By adjusting the blending ratio of the binder material in this way, the outer layer 4b coating surface does not contain pinholes or cracks, and suppresses the occurrence of significant irregularities that become shadows when viewed from the top surface, thereby shielding the surface. Formation of the layer 5 can be facilitated.
[0020]
Further, the blending ratio of the binder material in the paste composition forming the outer layer 4b is preferably 10% or more, more preferably 20% or more, in terms of mass ratio with respect to the conductive particles. However, since the electrical conductivity of the film (outer layer 4b) significantly decreases with an increase in the blending ratio of the binder material, it is preferable that the blending ratio of the binder material is small as long as the surface condition satisfies the above requirements. Or less, more preferably 70% or less.
[0021]
As a method for forming the outer layer 4b, a printing method is preferable. Moreover, if it is a printing method, there will be no restriction | limiting in particular, For example, a screen printing method, an inkjet method, a metal mask method etc. are mentioned.
Thus, by forming the outer layer 4b by a printing method, the surface roughness (roughness) is small, and cracks and pinholes do not occur. Therefore, the surface of the metal wiring layer 4 is smoothed, and the shielding layer 5 can be easily formed. Can be.
Furthermore, according to the printing method, the manufacturing cost can be reduced and the manufacturing efficiency can be improved.
[0022]
In addition, the outer layer 4b in this specification means the printing layer formed by the printing method for the above-mentioned purpose, and is not necessarily arrange | positioned in the outermost surface in the metal wiring layer 4, and if needed, it is further Another layer may be formed outside for some purpose.
[0023]
When comparing the coating thicknesses of the inner layer 4a and the outer layer 4b, it is desirable that the thickness of the outer layer 4b does not exceed 100% of the thickness of the inner layer 4a. If the thickness of the outer layer 4b exceeds 100% of the thickness of the inner layer 4a, the conductivity per volume of the circuit will be low, so that the circuit thickness will be too thick or the conductivity will be insufficient. There is a tendency.
[0024]
For both the inner layer 4a and the outer layer 4b, when a firing step for the purpose of, for example, fusion of conductive particles is required, considering application to a glass substrate, the temperature is 600 ° C. (preferably 550 ° C.) or less. It is preferable that necessary characteristics can be obtained at the firing temperature.
[0025]
In this invention, it is preferable to have the shielding layer 5 on the surface of the conductive layer composed of the metal wiring layer 4 and / or the transparent conductive layer 3.
As a material for forming the shielding layer 5, the electron transfer reaction rate with the redox pair-containing electrolytic solution that is in contact with the solar cell is low, the light transmission is excellent, and the movement of the generated photoelectrons is not hindered. Although it will not specifically limit if it has a characteristic, For example, a titanium oxide, a zinc oxide, niobium oxide, a tin oxide, a fluorine addition tin oxide (FTO), a tin addition indium oxide (ITO) etc. are mentioned. Can do.
[0026]
There is no restriction | limiting in particular as the method of forming the shielding layer 5, For example, the method of forming the target compound or its precursor into a film by dry methods (vapor phase method), such as sputtering method, vapor deposition method, CVD method, is mentioned. It is done. Further, when a precursor such as a metal is formed, the shielding layer 5 can be formed by oxidation by heat treatment or chemical treatment.
[0027]
In the case of a wet method, a solution in which a target compound or a precursor thereof is dissolved and dispersed is applied by a method such as a spin coating method, a dipping method, or a blade coating method, followed by a heat treatment or a chemical treatment. The shielding layer 5 can be formed by chemically changing to. Examples of the precursor include salts and complexes having a constituent metal element of the target compound. For the purpose of obtaining a dense film (shielding layer 5), it is preferably in a dissolved state rather than a dispersed state.
[0028]
In the case of spray pyrolysis (SPD) or the like, by heating the transparent substrate 2 having the transparent conductive layer 3 and spraying a substance that becomes the precursor of the shielding layer 5 toward the substrate, the substrate is thermally decomposed. The shielding layer 5 can be formed by changing to the target oxide semiconductor.
[0029]
Although there is no restriction | limiting in particular as thickness of the shielding layer 5, The thinner one is preferable in the range which can exhibit an effect, and about 10-3000 mm is preferable.
[0030]
In the electrode substrate 1 of the present invention, as shown in FIG. 2, in the structure in which the transparent conductive layer 3 is formed on the substrate after forming the metal wiring layer 4, the transparent conductive layer 3 also serves as the shielding layer 5. It does not matter.
[0031]
As described above, the electrode substrate 1 of the present invention does not have a shadowed portion such as pinholes or cracks on the surface of the outer layer 4b of the metal wiring layer 4, so that the surface is densely covered with the shielding layer 5. be able to.
[0032]
Next, a dye-sensitized solar cell using the electrode substrate 1 will be described.
The dye-sensitized solar cell of the present invention comprises, on the electrode substrate 1 described above, a working electrode provided with a dye-supported oxide semiconductor porous film, and a counter electrode disposed opposite to the working electrode, An electrolyte layer including a redox pair is provided between the working electrode and the counter electrode.
[0033]
Examples of the material of the semiconductor porous film include titanium oxide (TiO ₂ ), tin oxide (SnO ₂ ), tungsten oxide (WO ₃ ), zinc oxide (ZnO), niobium oxide (Nb ₂ O ₅ ), and the like. It can use individually or in combination of 2 or more types. It can also be obtained from commercially available fine particles, colloidal solutions obtained by the sol-gel method, and the like.
[0034]
As a method for producing a semiconductor porous film, for example, a colloidal solution or a dispersion liquid (including additives as required) is screen printing, ink jet printing, roll coating, doctor blade, spin coating, spray coating, etc. In addition to coating using various coating methods, it is possible to apply electrophoretic electrodeposition of fine particles, combined use of a foaming agent, complexation with polymer beads and the like (only the template component is removed later), and the like.
[0035]
As dyes supported on the semiconductor porous film, metal-containing complexes such as ruthenium complexes, porphyrins, and phthalocyanines containing bipyridine structure and terpyridine structure as ligands, and organic dyes such as eosin, rhodamine, and merocyanine should also be used. It is possible to select a material having an excitation behavior suitable for the application and the semiconductor used without any particular limitation.
[0036]
As the electrolytic solution for forming the electrolyte layer, an organic solvent containing a redox pair, a room temperature molten salt, and the like can be used. For example, acetonitrile, methoxyacetonitrile, propionitrile, propylene carbonate, diethyl carbonate, γ-butyrolactone, etc. Examples thereof include room temperature molten salts composed of organic solvents, quaternized imidazolium-based cations and iodide ions, bistrifluoromethylsulfonylimide anions, and the like.
Moreover, you may use what was quasi-solidified by introduce | transducing a suitable gelatinizer into such electrolyte solution, what is called a gel electrolyte.
[0037]
The oxidation-reduction pair is not particularly limited, and examples thereof include iodine / iodide ions, bromine / bromide ions, and the like. Specific examples of the former include iodide salts (lithium salts, quaternizations). A combination of iodine and imidazolium salt, tetrabutylammonium salt or the like can be used alone or in combination. Further, various additives such as tert-butylpyridine can be added to the electrolytic solution as necessary.
[0038]
A p-type semiconductor or the like can be used as the charge transport layer instead of the electrolyte layer formed from the electrolytic solution. Although there is no restriction | limiting in particular as a p-type semiconductor, For example, monovalent copper compounds, such as copper iodide and a copper thiocyanide, can be used conveniently. Moreover, various additives can be contained functionally as required for film formation.
There is no restriction | limiting in particular as a formation method of a charge transport layer, For example, film forming methods, such as a casting method, a sputtering method, and a vapor deposition method, are mentioned.
[0039]
As the counter electrode, for example, various carbon materials, platinum, gold, or the like can be formed on a conductive or non-conductive substrate by a method such as vapor deposition or sputtering.
Further, when a solid charge transport layer is used, a technique such as direct sputtering or coating may be used on the surface thereof.
[0040]
Since the dye-sensitized solar cell of the present invention has the electrode substrate 1 of the present invention, corrosion of the metal wiring by the electrolytic solution and reverse electron transfer from the metal wiring layer 4 to the electrolytic solution are suppressed, and the output of the photoelectric conversion element The effect is further improved.
[0041]
【Example】
Example 1
A silver paste (silver particles 92 / glass frit 8 (mass ratio)) for forming the inner layer 4a was screen-printed in a lattice pattern on the surface of a glass with an FTO film of 100 × 100 mm. This was dried at 135 ° C. for 20 minutes in a hot-air circulating furnace with a leveling time of 10 minutes, and then baked at 550 ° C. for 15 minutes. Next, using a CCD camera, a silver paste (silver particles 55 / glass frit 45 (mass ratio)) that forms the outer layer 4b while being aligned is overprinted, and at a leveling time of 10 minutes, 135 ° C., 20 After drying in a hot air circulating furnace for 5 minutes, a silver circuit was formed by baking at 550 ° C. for 15 minutes. The circuit width was 250 μm (outer layer 4b), 150 μm (inner layer 4a), and the film thickness was 8 μm (outer layer 3 μm + inner layer 5 μm).
An FTO layer having a thickness of 300 nm was formed on the surface of the substrate with wiring thus produced by a spray pyrolysis method to form a shielding layer 5 to obtain an electrode substrate (i).
[0042]
When the surface of the inner layer 4a and the surface of the outer layer 4b of the electrode substrate (i) was observed with an SEM, the inner layer 4a surface was observed with countless small holes of about 1 to 8 μm where glass frit did not flow. In contrast, almost no small holes were observed on the surface of the outer layer 4b, and a relatively smooth film surface of Ra 0.4 μm was obtained.
[0043]
A titanium oxide dispersion having an average particle diameter of 25 nm was applied to the electrode substrate (i), dried, and heated and sintered at 450 ° C. for 1 hour. This was immersed in an ethanol solution of ruthenium bipyridine complex (N3 dye) overnight to carry the dye. This was placed opposite to the platinum sputtered FTO substrate through a thermoplastic polyolefin resin sheet having a thickness of 50 μm, and the bipolar plate was fixed by thermally melting the resin sheet. In advance, an electrolyte injection port was opened on the platinum sputter electrode side, and a methoxyacetonitrile solution containing 0.5 M iodide salt and 0.05 M iodine as main components was injected between the electrodes. Then, the peripheral portion and the electrolyte solution inlet were main sealed with an epoxy-based sealing resin, and a silver paste was applied to the current collecting terminal portion to obtain a wiring type cell (i).
When photoelectric conversion characteristics were evaluated using AM1.5 pseudo-sunlight, the conversion efficiency of the wiring type cell (i) was 2.7%.
[0044]
(Example 2)
A silver circuit was formed on the heat-resistant glass substrate in the same manner as in Example 1, and an FTO film was formed on the surface of the substrate. This was used as the transparent conductive layer 3 and the shielding layer 5 to obtain an electrode substrate (ii).
Using this electrode substrate (ii), a wired cell (ii) was obtained in the same manner as in Example 1. When photoelectric conversion characteristics were evaluated using artificial sunlight of AM1.5, the conversion efficiency of the wiring type cell (ii) was 2.5%.
[0045]
(Example 3)
A gold circuit was formed on a 100 mm square FTO glass substrate by an additive plating method. The gold circuit was formed in a lattice shape on the substrate surface and had a circuit width of 50 μm. From this, a silver printed circuit was overprinted as the outer layer 4b, and dried and sintered in the same manner as in Example 1. The silver paste used contained silver particles 55 / glass frit 45 (mass ratio), and the film thickness was 8 μm (outer layer 3 μm + inner layer 5 μm). On this surface, an FTO layer of 300 nm was formed in the same manner as in Example 1 to form a shielding layer 5 to obtain an electrode substrate (iii).
Using this electrode substrate (iii), a wired cell (iii) was obtained in the same manner as in Example 1. When photoelectric conversion characteristics were evaluated using artificial sunlight of AM1.5, the conversion efficiency of the wiring type cell (iii) was 3.1%.
[0046]
(Comparative Example 1)
A silver paste (silver particles 92 / glass frit 8 (mass ratio)) is printed on a 100 mm square FTO glass substrate so as to have a circuit width of 250 μm and a film thickness of 8 μm, followed by drying and baking in the same manner as in Example 1. I concluded. On this surface, a 300 nm FTO layer was formed in the same manner as in Example 1 to form a shielding layer 5 to obtain an electrode substrate (iv).
Using this electrode substrate (iv), a wired cell (iv) was obtained in the same manner as in Example 1. When attention was paid to the electrolytic solution injected into the wiring type cell (iv), the brownish color immediately after the injection was changed to almost transparent after a few minutes. This seems to be because I ₃ ⁻ in the electrolytic solution reacted with silver exposed without being shielded and reduced to I ⁻ .
When photoelectric conversion characteristics were evaluated using artificial sunlight of AM1.5, the conversion efficiency of the wiring type cell (iv) was 0.29%.
[0047]
(Comparative Example 2)
A silver paste (silver particles 55 / glass frit 45 (mass ratio)) is printed on a 100 mm square FTO glass substrate so as to have a circuit width of 250 μm and a film thickness of 8 μm, and dried and baked in the same manner as in Example 1. I concluded. A 300 nm FTO layer was formed on this surface in the same manner as in Example 1 to form the shielding layer 5 to obtain an electrode substrate (v).
Using this electrode substrate (v), a wired cell (v) was obtained in the same manner as in Example 1. When photoelectric conversion characteristics were evaluated using artificial sunlight of AM1.5, the conversion efficiency of the wiring type cell (v) was 0.18%.
[0048]
(Comparative Example 3)
A gold circuit was formed on a 100 mm square FTO glass substrate by an additive plating method. The gold circuit was formed in a lattice shape on the substrate surface, and had a circuit width of 50 μm and a film thickness of 5 μm. A 300 nm FTO layer was formed on this surface in the same manner as in Example 1 to form the shielding layer 5 to obtain an electrode substrate (vi). The cross section of the electrode substrate (vi) was confirmed using SEM and EDX. As a result, the bottom of the circuit (wiring) was found to be due to the bottoming of the plating resist, and the shadow portion was not covered with FTO. It was. Using the electrode substrate (vi), a wired cell (vi) was obtained in the same manner as in Example 1. When photoelectric conversion characteristics were evaluated using artificial sunlight of AM1.5, the conversion efficiency of the wiring type cell (vi) was 0.3%.
[0049]
(Comparative Example 4)
Using a 100 mm square FTO glass substrate, a test cell (vii) was obtained in the same manner as in Example 1 with no wiring. When photoelectric conversion characteristics were evaluated using artificial sunlight of AM1.5, the conversion efficiency of the test cell (vii) was 0.11%.
[0050]
The wiring type cells of Examples 1 to 3 were all excellent in photoelectric conversion efficiency, whereas the wiring type cell (iv) of Comparative Example 1 had a single metal wiring layer 4. Since the shielding by the shielding layer 5 was insufficient, the characteristics of the electrode substrate could not be extracted and the conversion efficiency was not good. Further, in the wiring type cell (v) of Comparative Example 2, the metal wiring layer 4 is composed of one layer, and its volume resistivity is high, so that the resistance of the electrode substrate cannot be reduced and high output cannot be obtained. Therefore, the conversion efficiency was not good. Further, in the wiring type cell (vi) of Comparative Example 3, the metal wiring layer 4 is composed of one layer, and the shielding by the shielding layer 5 is insufficient, so that the characteristics of the electrode substrate cannot be extracted, Conversion efficiency was not good.
[0051]
【The invention's effect】
The electrode substrate 1 of the present invention provides a substrate surface that can reduce the surface roughness (roughness) of the metal wiring layer 4 and form a dense shielding layer 5 without pinholes. According to the dye-sensitized solar cell having such an electrode substrate 1, the corrosion of the metal wiring by the electrolytic solution and the reverse electron transfer from the metal wiring layer 4 to the electrolytic solution are suppressed, and the output effect of the photoelectric conversion element is further increased. improves.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing an embodiment of an electrode substrate of the present invention.
FIG. 2 is a schematic cross-sectional view showing an embodiment of an electrode substrate of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Electrode substrate, 2 ... Transparent substrate, 3 ... Transparent conductive layer, 4 ... Metal wiring layer, 4a ... Inner layer, 4b ... Outer layer, 5 ... Shielding layer

Claims (5)

An electrode substrate having a metal wiring layer and a transparent conductive layer on a transparent substrate,
In the overlapping part of the metal wiring layer and the transparent conductive layer, the metal wiring layer is disposed below or on the transparent conductive layer,
The metal wiring layer is composed of at least two layers of an inner layer and an outer layer ,
The volume resistivity of the inner layer is smaller than the volume resistivity of the outer layer,
The outer layer is formed of a paste composition containing at least conductive particles and a binder material, and the blending ratio of the binder material of the paste composition is a binder material blend in the composition that forms another layer in the metal wiring layer Bigger than the ratio,
An electrode substrate for a dye-sensitized solar cell , comprising a shielding layer on a surface of a conductive layer composed of the metal wiring layer and / or the transparent conductive layer . 2. The dye-sensitized solar cell electrode substrate according to claim 1, wherein the outer layer is formed by a printing method. The electrode substrate for a dye-sensitized solar cell according to claim 1 or 2 , wherein the composition forming the metal wiring layer contains silver or nickel. It has the electrode substrate for dye-sensitized solar cells in any one of Claims 1-3 , The photoelectric conversion element characterized by the above-mentioned. A dye-sensitized solar cell comprising the photoelectric conversion element according to claim 4 .

Images