JP5208431B2 - Manufacturing method of electrode substrate, manufacturing method of photoelectric conversion element, manufacturing method of dye-sensitized solar cell - Google Patents

Description

The present invention relates to a method for producing an electrode substrate suitably used for a photoelectric conversion element typified by a dye-sensitized solar cell, and particularly has a metal wiring layer and a transparent conductive layer. The present invention relates to a method for manufacturing an electrode substrate that can suppress deterioration of characteristics due to electrical leakage to the metal and corrosion of a metal wiring layer.

  Dye-sensitized solar cells were developed by Gretzell et al. In Switzerland, and have advantages such as high photoelectric conversion efficiency and low manufacturing costs, and are attracting attention as a new type of solar cells (for example, patents) Reference 1 and non-patent reference 1).

The dye-sensitized solar cell has a working electrode having an oxide semiconductor porous film in which a photosensitizing dye composed of oxide semiconductor fine particles is supported on an electrode substrate, a counter electrode provided opposite to the working electrode, and an action And an electrolyte layer formed by filling an electrolyte between the electrode and the counter electrode.
This type of dye-sensitized solar cell functions as a photoelectric conversion element that converts oxide energy into electric power by sensitizing oxide semiconductor particles with a photosensitizing dye that absorbs incident light such as sunlight (for example, patents). Reference 1, Non-Patent Document 1, etc.).

As the transparent electrode substrate used in the dye-sensitized solar cell as described above, a transparent conductive film such as tin-added indium oxide (ITO) or fluorine-added tin oxide (FTO) is generally formed on the surface of the substrate. It is. However, the specific resistance of ITO and FTO is about 10 ⁻⁴ [Ω · cm], which is about 100 times the specific resistance of metals such as silver and gold. In such a case, the photoelectric conversion efficiency is reduced.
As a technique for reducing the resistance of the transparent electrode substrate, it is conceivable to increase the formation thickness of the transparent conductive film (ITO, FTO, etc.), but if the film is formed with such a thickness that the resistance value is sufficiently reduced, the transparent conductive layer The light absorption due to increases. For this reason, since the transmission efficiency of incident light is significantly reduced, the photoelectric conversion efficiency is easily lowered.

  As a solution to this problem, studies have been made to reduce the resistance of the electrode substrate by providing metal wiring on the surface of the transparent electrode substrate to such an extent that the aperture ratio is not significantly impaired (see, for example, Patent Document 2). ). In this case, at least a surface portion of the metal wiring needs to be protected by some shielding layer in order to prevent corrosion of the metal wiring due to the electrolytic solution and leakage of electric current from the metal wiring to the electrolytic solution. The shielding layer is required to be capable of densely covering the circuit board and to have excellent chemical resistance against the electrolyte solution constituting the electrolyte layer. Insulating resin, glass, etc. can be cited as materials that meet such requirements, but the substrate may undergo a thermal history when forming an oxide semiconductor porous film. It is desirable to use excellent glass.

However, the shielding layer made of glass is vulnerable to deformation, and easily cracks when the shielding layer is formed or due to a volume change accompanying heat treatment after the shielding layer is formed. When the crack generated in the shielding layer reaches the metal wiring, the function of the cell may be impaired due to leakage from the metal wiring to the electrolytic solution or corrosion of the metal wiring by the electrolytic solution.
Japanese Patent Laid-Open No. 01-220380 JP 2003-203681 A M. Graetzel et al., Nature (UK), 1991, No. 353, p. 737

  The present invention has been made in view of the above circumstances, can reduce the resistance of the electrode substrate, and suppresses deterioration of characteristics due to leakage from the metal wiring to the electrolyte and corrosion of the metal wiring layer. It is an object of the present invention to provide an electrode substrate and a photoelectric conversion element that can be used.

In the method for manufacturing an electrode substrate according to claim 1 of the present invention, a transparent conductive layer, a metal wiring layer, and an insulating layer made of low-melting glass covering the metal wiring layer are sequentially stacked on a base material made of glass. a method of manufacturing an electrode substrate for distribution, the thermal expansion coefficient of the base material alpha, the case where the thermal expansion coefficient of the insulating layer is defined as beta, a value obtained by dividing the beta in the alpha is 0.8 or more 1 .44 the following become material, the base material, and wherein the Rukoto used as the insulating layer.
Method of manufacturing an electrode substrate according to claim 2 of the present invention, Oite to claim 1, as a material constituting the insulating layer, which is characterized by using the low-melting glass containing no lead element.
Method of manufacturing an electrode substrate according to claim 3 of the present invention, in claim 1 or 2, as the material constituting said substrate, and wherein the Rukoto using a high strain point glass.
The manufacturing method of the photoelectric conversion element which concerns on Claim 4 of this invention is manufactured using the manufacturing method of the electrode substrate as described in any one of Claims 1 thru | or 3 .
Method for manufacturing a dye-sensitized solar cell according to claim 5 of the present invention is characterized that you manufactured by the method of a photoelectric conversion element according to claim 4.

  The electrode substrate according to the present invention comprises a transparent conductive layer, a metal wiring layer, and an insulating layer covering the metal wiring layer, which are sequentially stacked on the base material, and the thermal expansion coefficient β of the insulating layer is determined as the base material. By adopting a configuration in which the value divided by the coefficient of thermal expansion α is in the range of 0.5 to 1.8, the resistance of the electrode substrate can be reduced, and leakage from the metal wiring to the electrolyte And deterioration of characteristics due to corrosion of the metal wiring layer can be suppressed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing an example of an electrode substrate according to the present invention. An electrode substrate 1 shown in FIG. 1 includes a transparent conductive layer 11, a metal wiring layer 12, and an insulating layer 14 covering the metal wiring layer on one surface (hereinafter also referred to as "surface") of a base material 10. When the thermal expansion coefficient of the base material 10 is defined as α and the thermal expansion coefficient of the insulating layer 14 is defined as β, the value obtained by dividing the β by the α is 0.5 or more and 1.8. The configuration satisfies the following range.

As the material of the base material 10, the thermal expansion coefficient α and the thermal expansion coefficient β of the insulating layer 14 satisfy the relational expression “0.5 ≦ (β / α) ≦ 1.8”, and light transmittance. As long as it has, the light transmittance is not particularly limited, but it is preferable that the light transmittance is as high as possible. A configuration satisfying the relational expression “0.8 ≦ (β / α) ≦ 1.5” is more preferable. As specific examples, high strain point glass, soda lime glass, white plate glass, borosilicate glass, and the like can be used. High strain point glass is preferable because it is less deformed by heat treatment and has excellent heat resistance. For example, one having a thermal expansion coefficient of 86 × 10 ⁻⁷ can be used.

The transparent conductive layer 11 is formed on the surface of the substrate 10 over a region wider than the region where the metal wiring layer 12 is formed. The transparent conductive layer 11 can be a single layer (single layer) or a plurality of layers (stacked). The material of the transparent conductive layer 11 can be selected according to the application in consideration of light transmittance, conductivity, and the like.
The thickness of the transparent conductive layer 11 is preferably 0.05 to 5 μm. When the thickness of the transparent conductive layer 11 is less than 0.05 μm, the sheet resistance increases as compared with the transparent conductive layer 11 having a thickness of 0.05 to 5 μm, which may cause a decrease in photoelectric conversion efficiency. On the other hand, when the thickness of the transparent conductive layer 11 exceeds 5 μm, the light transmittance is remarkably lowered and the photoelectric conversion efficiency is lowered, which is not good.

Specific examples of the transparent conductive layer 11 include one or more layers made of a conductive metal oxide such as tin-added indium oxide (ITO), indium oxide, tin oxide (SnO ₂ ), and fluorine-added tin oxide (FTO). It can be a layer. Tin-added indium oxide (ITO) is superior in light transmittance and conductivity to fluorine-added tin oxide (FTO), but is inferior in heat resistance. Moreover, although fluorine addition tin oxide (FTO) is excellent in heat resistance compared with tin addition indium oxide (ITO), it is inferior in light transmittance and electroconductivity. When a composite film of fluorine-added tin oxide (FTO) and tin-added indium oxide (ITO) is used as the transparent conductive layer 11, the disadvantages of both are offset and an excellent transparent conductive layer 11 having the advantages of both is obtained. .
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.

The metal wiring layer 12 is formed by wiring a metal such as gold, silver, platinum, aluminum, nickel, titanium, and the like, and is electrically connected to the transparent conductive layer 11 and insulated by an insulating layer 14. . The wiring pattern of the metal wiring layer 12 is not particularly limited, and may be a lattice pattern as shown in FIG. 2, or a striped pattern, a strip pattern, a comb pattern, or a combination thereof. be able to.
In order not to significantly impair the light transmittance of the electrode substrate 1, for example, it is desirable that the width of each wiring be 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 50 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, a plating method, or a dispensing method can also be used.
Although the surface of the metal wiring layer 12 is preferably smooth, priority is given to having higher conductivity than this, and there may be some undulations and irregularities.
The specific resistance of the metal wiring layer 12 is at least 9 × 10 ⁻⁵ [Ω · cm] or less, more preferably 5 × 10 ⁻⁵ [Ω · cm] or less.

The insulating layer 14 is made of an amorphous or crystalline, and further a composite low melting point glass layer. The insulating layer 14 is a low-melting glass containing lead oxide such as PbO—P ₂ O ₅ —SnF ₂ or PbO—SiO ₂ —B ₂ O ₃ , or a borosilicate bismuth salt, bismuth zinc borate, or aluminophosphate. A low-melting glass layer made of non-lead low-melting glass such as zinc-based, zinc phosphate-based, or borosilicate-based is formed on a region where one or a plurality of layers and the metal wiring layer 12 are formed by a printing method or the like. By forming a film, the metal wiring layer is insulated and coated. The insulating layer 14 is particularly preferably one that does not contain lead in terms of environment or safety. When the insulating layer 14 is composed of a plurality of layers, it can be formed of, for example, two or more kinds of low melting glass having different melting temperatures.

  According to the electrode substrate 1 of this embodiment, since the metal wiring layer 12 is provided on the transparent conductive layer 11, the resistance of the electrode substrate 1 can be reduced. Further, according to the electrode substrate 1 of the present embodiment, the thermal expansion coefficient α of the base material 10 and the thermal expansion coefficient β of the insulating layer 14 are expressed by the relational expression “0.5 ≦ (β / α) ≦ 1.8”. And the transparent conductive layer 11 has a thickness of 0.05 to 5 μm, so that cracks due to volume changes due to heat treatment are unlikely to occur, and leakage from the metal wiring to the electrolyte or metal wiring layer It is possible to suppress deterioration of characteristics due to corrosion. Moreover, since the insulating layer 14 is a low-melting glass layer in the electrode substrate 1 of the present embodiment, the metal wiring layer 12 can be densely coated and has excellent chemical resistance against the electrolytic solution constituting the electrolyte layer. Become.

  Hereinafter, modified examples of the electrode substrate of the present invention will be described. In the following modified example of the electrode substrate, the same reference numerals as those in FIG. 1 indicate the same or similar configuration as the electrode substrate shown in FIG. 1, and redundant description may be omitted.

  The electrode substrate shown in FIG. 3 is different from the electrode substrate shown in FIG. 1 in that a shielding layer 13 is provided on the transparent conductive layer 11. Although the problem is small compared with the metal wiring layer 12, since leakage from the transparent conductive layer 11 has been pointed out, providing a shielding layer 13 so as to cover the transparent conductive layer 11 provides 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 high light transmittance and high photoelectron transfer ability is selected, and titanium oxide (TiO ₂ ), zinc oxide ( Examples thereof include oxide semiconductors such as ZnO), niobium oxide (Nb ₂ O ₅ ), and tin oxide (SnO ₂ ).
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 1 to 1000 nm.

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 preferable to a dispersion. As another method for forming the shielding layer 13, for example, a spray pyrolysis method is used, and the substrate 10 having the transparent conductive layer 11 is heated and becomes a precursor of the shielding layer 13 toward the substrate 10. A method of forming the shielding layer 13 by spraying a substance and thermally decomposing it to change it into a target oxide semiconductor can also be used.
In this way, by providing the shielding layer 13 for shielding the transparent conductive layer 11, leakage from the transparent conductive layer 11 can be suppressed, so that a photoelectric conversion element with higher photoelectric conversion efficiency is produced. Can do.

Next, the photoelectric conversion element of the present invention will be described.
In FIG. 4, an example of the photoelectric conversion element which comprises a dye-sensitized solar cell is shown. This photoelectric conversion element 6 includes a working electrode 3 having an oxide semiconductor porous film 2 on the electrode substrate 1 shown in FIG. 1 and a counter electrode 4 provided to face the working electrode 3. A charge transfer layer 5 made of an electrolyte such as an electrolyte is formed between the working electrode 3 and the counter electrode 4. In the photoelectric conversion element 6 shown in FIG. 4, an oxide semiconductor porous film 2 carrying a sensitizing dye is formed on the surface of the electrode substrate 1, and the electrode substrate 1 and the oxide semiconductor porous film 2 The working electrode 3 of the photoelectric conversion element 6 is configured.
In addition, in FIG. 4, although the electrode substrate 1 illustrated the electrode substrate 1 of the structure shown in FIG. 1, it is not limited to this.

The oxide semiconductor porous film 2 includes one or more 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. Is a porous thin film made of oxide semiconductor fine particles. The average particle diameter of the oxide semiconductor fine particles is preferably in the range of 1 to 1000 nm. The thickness of the oxide semiconductor porous film 2 is preferably about 0.5 to 50 μm.

  The method for forming the oxide semiconductor porous film 2 is not particularly limited, but can be adjusted by, for example, a dispersion obtained by dispersing commercially available oxide semiconductor fine particles in a desired dispersion medium, or a sol-gel method. Examples include a method in which a colloid solution is applied by a known application method 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 after adding desired additives as necessary. It is done. In addition, after the electrode substrate 1 is immersed in a colloid solution and electrophoretic deposition in which oxide semiconductor fine particles are adhered to the electrode substrate 1 by electrophoresis, a foaming agent is mixed and applied to the colloid solution or dispersion, It is possible to apply a method of sintering to make porous, a method in which polymer microbeads are mixed and applied, and then the polymer microbeads are removed by heat treatment or chemical treatment to form voids to make them porous. it can.

  The sensitizing dye supported on the oxide semiconductor porous film 2 is not particularly limited, and includes, for example, a ruthenium complex, an iron complex, a porphyrin-based or a phthalocyanine-based including a bipyridine structure, a terpyridine structure, or the like as a ligand. From metal complexes, organic dyes such as coumarins, eosin, rhodamine, merocyanine, and the like, those having an excitation behavior suitable for applications and oxide semiconductors can be appropriately selected and used.

  When the charge transport layer 5 is composed of an electrolyte, for example, an electrolytic solution containing a redox pair can be used. Alternatively, a gel electrolyte obtained by quasi-solidifying the electrolyte solution with a suitable gelling agent such as a polymer gelling agent, a low molecular weight gelling agent, various nanoparticles, or carbon nanotubes may be used. Solvents for the electrolyte include organic solvents such as acetonitrile, methoxyacetonitrile, propionitrile, propylene carbonate, diethyl carbonate, and γ-butyrolactone, imidazolium cations, pyrrolidinium cations, pyridinium cations and iodide ions, and bistrifluoro A room temperature molten salt composed of a methylsulfonylimide anion, a dicyanoamide anion, a thiocyanate anion, or the like can be selected and used.

  The redox pair contained in the electrolyte is not particularly limited, and can be obtained by adding a pair of iodine / iodide ions, bromine / bromide ions and the like. 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. If necessary, additives such as 4-tert-butylpyridine (TBP), N-methylbenzimidazole, guanidinium salt, or a derivative thereof may be added to the electrolyte.

As the counter electrode 4, for example, on a conductive substrate or a substrate made of a non-conductive material such as glass, various carbon-based materials, a conductive polymer, a metal material such as gold or platinum, or a conductive material such as ITO or FTO. An electrode formed with an electrode made of an oxide semiconductor can be used.
If the electrode is a platinum film, for example, a method of applying chloroplatinic acid and heat-treating it can be exemplified. Further, the electrode may be formed by vapor deposition or sputtering.

  According to the photoelectric conversion element 6 of the present embodiment, since the electrode substrate 1 has the metal wiring layer 12 electrically connected to the transparent conductive layer 11, the resistance of the electrode substrate 1 can be reduced. And cell characteristics can be greatly improved. Moreover, according to the electrode substrate 1 of the present embodiment, when the thermal expansion coefficient of the substrate 10 is defined as α and the thermal expansion coefficient of the insulating layer 14 is defined as β, the relational expression “0.5 ≦ (β / α) ≦ 1. 8 ”is satisfied, it is difficult for cracks due to volume changes due to heat treatment to occur, and the metal wiring layer 12 is reliably shielded from the electrolytic solution of the charge transfer layer 5 and the like. It is possible to suppress deterioration of characteristics due to electric leakage or corrosion of the metal wiring layer.

<Experimental example 1>
In this example, the electrode substrate shown in FIG. 1 was produced by the following procedure.
First, a saturated aqueous solution of ammonium fluoride was added and dissolved in an ethanol solution of tin (IV) chloride pentahydrate to prepare an FTO film raw material solution.
Next, the FTO film raw material liquid is applied to the one surface of the substrate 10 using a spray nozzle while the other surface (hereinafter also referred to as “back surface”) of the substrate 10 is placed and heated so as to be in contact with the heater plate. The transparent conductive layer 11 was obtained by spraying on (it is also called "the surface" hereafter) and forming a FTO film | membrane (film thickness is adjusted in the range of 0.05-5 micrometers).
Here, as the substrate 10, high strain point glass (Asahi Glass Co., Ltd .: PD200, 140 mm square, thickness 2.8 mm) was used.

Next, a silver paste for printing (with a volume resistivity of 3 × 10 ⁻⁶ [Ω · cm] after sintering) is screen-printed on the transparent conductive layer 11 made of an FTO film, and after leveling for 10 minutes, The metal wiring layer 12 which makes a silver circuit was obtained by drying at 130 degreeC and baking at the maximum temperature of 510 degreeC.
Here, the circuit width (design value) of the metal wiring layer 12 was 300 μm, the film thickness was 10 μm, and the metal wiring layer 12 was formed in a shape extending in a grid pattern from the current collecting terminals. Subsequently, while aligning using a CCD camera, the metal wiring layer 12 was superposed, and a low-melting glass was applied by screen printing, dried at 130 ° C., and baked at a maximum of 500 ° C. This operation was repeated a plurality of times to obtain an insulating layer 14 that plays the role of wiring protection, and used as an electrode substrate of Experimental Example 1 (hereinafter also referred to as “Sample 1”).
Here, as the insulating layer 14, low melting point glass A (Fukuda Metal Foil Powder Co., Ltd., lead borate type) was used.
In addition, the formation width (design value) of the insulating layer 14 was 600 μm formed on both sides of the metal wiring layer 12 in the width direction by an excess of 150 μm per side.

<Experimental example 2>
This example is different from Experimental Example 1 only in that heat-resistant glass (manufactured by SCHOTT: TEMPAX 8330, 140 mm square, thickness 1.1 mm) is used as the base material 10 instead of the high strain point glass. In the same manner as in Example 1, an electrode substrate (hereinafter also referred to as “sample 2”) was produced.

<Experimental example 3>
In this example, the insulating layer 14 is different from Experimental Example 1 only in that the low melting point glass B (Fukuda Metal Foil Powder Industry Co., Ltd., zinc silicate phosphorus system) is used, and other points are the same as Experimental Example 1. An electrode substrate (hereinafter also referred to as “sample 3”) was produced.

<Experimental example 4>
This example is different from Experimental Example 3 only in that heat-resistant glass (manufactured by SCHOTT: TEMPAX 8330, 140 mm square, thickness 1.1 mm) is used as the base material 10 instead of the high strain point glass. In the same manner as in Example 3, an electrode substrate (hereinafter also referred to as “sample 4”) was produced.

<Experimental example 5>
In this example, the insulating layer 14 is different from Experimental Example 1 only in that a low melting point glass C (manufactured by Fukuda Metal Foil Powder Industry Co., Ltd., bismuth borate) is used. A substrate (hereinafter also referred to as “sample 5”) was produced.

<Experimental example 6>
This example is different from Experimental Example 5 only in that a heat-resistant glass (manufactured by SCHOTT: TEMPAX 8330, 140 mm square, thickness 1.1 mm) is used as the base material 10 instead of the high strain point glass. In the same manner as in Example 5, an electrode substrate (hereinafter also referred to as “sample 6”) was produced.

  The materials and thermal expansion coefficients of the base material 10 and the insulating layer 14 used in Experimental Examples 1 to 6 are summarized in Table 1. In Table 1, α is “the coefficient of thermal expansion of the substrate”, β is “the coefficient of thermal expansion of the insulating layer”, ○ is “no damage”, x is “damaged (crack reaching the Ag wiring) ) ". As is clear from the “β / α” column, the experimental examples 1, 3, and 5 satisfy the relational expression “0.5 ≦ (β / α) ≦ 1.8” according to the present invention. On the other hand, the remaining experimental examples 2, 4, and 6 are examples that deviate from this relational expression.

  The electrode substrate (samples 1 to 6) obtained in each experimental example was observed using an optical microscope or an electron microscope. As a result, as shown in the “Wiring Protection Characteristics” column of Table 1, the results were obtained by Experimental Examples 1, 3, and 5 satisfying the relational expression “0.5 ≦ (β / α) ≦ 1.8” according to the present invention. In the electrode substrate (samples 1, 3, and 5), it was confirmed that the insulating layer 14 did not crack to reach the Ag layer, and a dense insulating layer 14 preferable as a wiring protective layer was formed. On the other hand, in the electrode substrates (samples 2, 4, and 6) obtained in Experimental Examples 2, 4, and 6, which are examples that deviate from the relational expression according to the present invention, cracks that reach the Ag layer in the insulating layer 14 Was found to occur.

<Evaluation 1: Electrode corrosion resistance>
A glass substrate 12 on which an electrode composed of a platinum layer and an FTO film is formed on the surface with an insulating resin sheet having a thickness of 50 μm interposed as a spacer, serving as a counter electrode, is prepared by each experimental example. Each of (Samples 1 to 6) is overlaid so that the wiring formation surface faces the counter electrode, and after injecting an iodine electrolyte between both substrates, the sample is left for a while.
After step 1, an appearance inspection was performed. As a result, in the three samples (samples 1, 3, and 5) in which the dense protective layer was formed, the appearance was not changed, whereas the samples in which the protective layer was cracked (samples 2, 4, and 5). In 6), corrosion of the silver circuit occurred due to the penetration of the iodine electrolyte, and discoloration of the iodine electrolyte was observed.

<Evaluation 2: Element characteristics>
Dye-sensitized solar cells (photoelectric conversion elements) were prepared using the electrode substrates (samples 1 to 6) obtained in each experimental example, and the characteristics were evaluated. The device fabrication method and measurement conditions are as follows.
(1) After forming the metal layer 12 forming the silver circuit on a substrate, a paste containing TiO ₂ nanoparticles was applied by screen printing, dried and sintered at 500 ° C..
(2) Next, an insulating layer 14 serving as a wiring protective layer was formed, and this was immersed in an acetonitrile / t-butanol solution of ruthenium bipyridine complex (N719 dye) for more than one day and night to support the dye, thereby obtaining a photoelectrode.
(3) As a counter electrode, a Ti foil on which a platinum layer was formed by sputtering was prepared.
(4) In a circulating and purifying glove box filled with an inert gas, an iodine electrolyte was developed on the photoelectrode, faced with the counter electrode, overlapped with each other, and then the periphery was sealed with an ultraviolet curable resin.
With the above configurations (1) to (4), dye-sensitized solar cells using the electrode substrates (samples 1 to 6) of the respective experimental examples were obtained.

At that time, the following was used as the iodine electrolyte.
Electrolyte A is “dissolving 0.5M 1,2-dimethyl-3-propylimidazolium iodide and 0.05M iodine in methoxyacetonitrile, and adding an appropriate amount of lithium iodide and 4-t-butyl. “Addition of pyridine”.
The electrolyte b was prepared by mixing “1-hexyl-3-methylimidazolium iodide and iodine in a molar ratio of 10: 1, adding an appropriate amount of N-methylbenzimidazole and guanidinium thiocyanate to this, “4 wt% SiO ₂ nanoparticles were blended and kneaded sufficiently to form a quasi-solid state”.

The power generation characteristics of the dye-sensitized solar cell were measured by irradiating simulated sunlight with AM 1.5, 100 mW / cm ² . Table 2 summarizes the power generation characteristics of the dye-sensitized solar cells (photoelectric conversion elements) using the electrode substrates (samples 1 to 6) obtained in each experimental example.

From Table 2, the following points became clear.
(B) In the battery using the electrode substrate (samples 2, 4, 6) in which the protective layer was cracked, the corrosion of the silver wiring had already begun at the time of measurement, and the current collecting function was impaired, so the internal resistance was Raises and lowers output.
(B) In contrast, a battery using an electrode substrate (samples 1, 3, and 5) on which a dense wiring protective layer is formed has good photoelectric conversion characteristics.
Although not listed in Table 2, in the battery using the electrode substrate (samples 2, 4, 6) in which the (wiring) protective layer was cracked (communication), the output tends to decrease with the passage of time thereafter. Admitted.
From the above evaluation results, the electrode substrate in which the thermal expansion coefficient α of the base material 10 and the thermal expansion coefficient β of the insulating layer 14 satisfy the relational expression “0.5 ≦ (β / α) ≦ 1.8” It was confirmed that deterioration of characteristics due to leakage from the wiring to the electrolyte and corrosion of the metal wiring layer was suppressed, and a photoelectric conversion element having good power generation characteristics was obtained.

It is sectional drawing which shows the 1st example of the electrode substrate of this invention. It is a fragmentary top view which shows an example of the planar shape of a metal wiring layer. It is sectional drawing which shows the 2nd example of the electrode substrate of this invention. It is sectional drawing which shows one embodiment of the photoelectric conversion element of this invention. It is sectional drawing of the width direction of the metal wiring layer which expanded and showed a part of electrode substrate, (a) is the case where the relational expression of this invention is satisfy | filled, (b) is the case where the relational expression of this invention is not satisfy | filled. is there.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Electrode substrate, 2 Oxide semiconductor porous film, 3 Working electrode, 4 Counter electrode, 5 Charge transfer layer, 6 Photoelectric conversion element, 10 Base material, 11 Transparent conductive layer, 12 Metal wiring layer, 13 Shielding layer, 14 Insulating layer, 21 Crack, 31 Corrosion.

Claims (5)

A method for producing an electrode substrate, wherein a transparent conductive layer, a metal wiring layer, and an insulating layer made of low-melting glass covering the metal wiring layer are sequentially stacked on a substrate made of glass,
When the coefficient of thermal expansion of the substrate is defined as α and the coefficient of thermal expansion of the insulating layer is defined as β, a material in which the value obtained by dividing β by α is 0.8 or more and 1.44 or less is used. The electrode substrate is used as the insulating layer.   The method for manufacturing an electrode substrate according to claim 1, wherein the low-melting glass not containing lead element is used as a material constituting the insulating layer.   The method for producing an electrode substrate according to claim 1, wherein high strain point glass is used as a material constituting the base material. It manufactures using the manufacturing method of the electrode substrate as described in any one of Claims 1 thru | or 3 , The manufacturing method of the photoelectric conversion element characterized by the above-mentioned.   It manufactures using the manufacturing method of the photoelectric conversion element of Claim 4, The manufacturing method of the dye-sensitized solar cell characterized by the above-mentioned.

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