JP5171139B2 - Electrode materials for dye-sensitized solar cells - Google Patents

Description

  The present invention relates to a material constituting an electrode of a dye-sensitized solar cell, and relates to an electrode material used for a “counter electrode” or a “photo electrode” which is not required to be provided on the side opposite to a light receiving surface.

  Currently, solar cells using silicon as the photoelectric conversion element are the mainstream, but the practical application of “dye-sensitized solar cells” is being studied as a more economical next-generation solar cell to replace this. .

  FIG. 1 schematically shows the structure of a conventional dye-sensitized solar cell. (A) is a type having a photoelectric conversion layer on the incident light side electrode, and (b) is a type in which the incident light side electrode is a “counter electrode” for passing electrons to ions in the solution.

In the type of FIG. 1A, the solar cell 1 is configured by the photoelectrode 3 formed on the surface of the transparent substrate 2 and the counter electrode 5 formed on the surface of the substrate 4 facing each other. Since this type of photoelectrode 3 needs to transmit light, it is usually composed of a transparent conductive film such as ITO (indium-tin oxide), FTO (fluorine-doped tin oxide), or TO (tin oxide). . Glass or the like is used for the transparent substrate 2. A photoelectric conversion layer 6 is formed on the surface of the photoelectrode 3. The photoelectric conversion layer 6 are porous layer made of large TiO ₂ particles 7 of the specific surface area, the surface of the TiO ₂ particles 7 Ru dyes 8 is doped. An electrolyte solution 9 containing iodide ions is filled between the photoelectric conversion layer 6 and the counter electrode 5. Since the counter electrode 5 needs to exhibit excellent corrosion resistance with respect to the electrolyte solution 9 containing iodide ions, the counter electrode 5 is made of noble metal such as platinum, ITO, FTO, or TO. A load 10 is connected by a conducting wire between the photoelectrode 3 and the counter electrode 5 outside the solar cell 1 to form a circuit.

When the incident light 20 reaches the Ru dye 8, the Ru dye 8 absorbs light and is excited, and its electrons are injected into the TiO ₂ particles 7. The excited Ru dye 8 receives electrons from the iodide ion I ^{− in} the electrolyte solution 9 and returns to the ground state. I ⁻ is oxidized to I ₃ ⁻ , diffuses to the counter electrode 5, receives electrons from the counter electrode 5, and returns to I ⁻ . As a result, electrons move along the route of Ru dye 8 → TiO ₂ particles 7 → photoelectrode 3 → load 10 → counter electrode 5 → electrolyte solution 9 → Ru dye 8. As a result, a current for operating the load 10 is generated.

  In the type of FIG. 1B, the counter electrode 5 is made of a transparent conductive film such as ITO, FTO, or TO that transmits light, and the photoelectric conversion layer 6 is formed on the surface of the photoelectrode 3 that is the other electrode. . In this case, the photoelectrode 3 is not necessarily transparent. The principle of current generation is basically the same as the type shown in FIG.

  Patent Documents 1 to 6 describe that a conductive film made of a corrosion-resistant metal such as platinum is used for an electrode of a dye-sensitized solar cell. There is also an example in which the counter electrode is formed of a platinum plate having a thickness of 1 mm (Patent Document 6).

Japanese Patent Laid-Open No. 11-273753 JP 2004-3111197 A JP 2006-147261 A JP 2007-48659 A JP 2004-165015 A JP 2005-235644 A

  In order to promote the spread of dye-sensitized solar cells, there is a strong demand for the construction of technology that can further improve performance and reduce costs. One of the important matters is the development of elemental technology that improves the electrical conductivity of the electrode by a method that is as inexpensive as possible.

  In a dye-sensitized solar cell, if a transparent electrode is used for both the “photoelectrode” and the “counter electrode”, the decrease in conductivity becomes large. To alleviate this, it is not necessary to transmit light. It is advantageous that the “electrode” or “counter electrode” is made of a metal material having a low electric resistance. However, since an electrolyte solution containing iodide ions is used, it is necessary to employ a metal material having sufficient corrosion resistance against iodide ions.

  Examples of such a corrosion-resistant material include noble metal materials such as gold (Au) and platinum (Pt). Of these, platinum is suitable as an electrode material because it has a catalytic action. However, since noble metals are expensive, for example, an electrode material made of a platinum plate as disclosed in Patent Document 6 cannot be used as a practical component of a solar cell. Even when the electrode is configured by providing a platinum film on the substrate, the thickness of the platinum film is considerably increased in order to obtain sufficient conductivity when the electric conduction in the electrode is to be borne only by the platinum film. Necessary and inevitably the cost is high. Therefore, when the surface of the electrode is covered with platinum, it is desirable to ensure conductivity in the electrode by using another conductive material for the base.

  Platinum also exhibits good corrosion resistance against iodide ions contained in the electrolyte solution of the dye-sensitized solar cell. However, even if the surface of the electrode is covered with a platinum film, the corrosion resistance of the underlying material is not unnecessary. A platinum film can be formed by various plating methods, but defects such as pinholes are usually unavoidable in the film. This is especially true when it is desired to make the platinum film as thin as possible. It is also assumed that the platinum film is wrinkled in the manufacturing process and the underlying material is exposed. For this reason, it is desirable that the material used as the base of the platinum film also exhibits sufficient corrosion resistance when exposed to an electrolyte solution containing iodide ions. Specifically, when the material is directly coated with an electrolyte solution containing iodide ions without being coated with platinum or the like, a material exhibiting excellent corrosion resistance so that corrosion does not proceed may be used as a base. preferable. Even when the surface is covered with a catalyst layer using carbon black or an organometallic complex as well as a platinum film, the underlying material is required to have excellent corrosion resistance in an electrolyte solution containing iodide ions. The point remains the same.

  Stainless steel is a metal material that is inherently excellent in corrosion resistance. However, the corrosion resistance in an electrolyte solution containing iodide ions is not sufficiently grasped, and it is known that at least general-purpose stainless steel types such as SUS430 and SUS304 cause severe corrosion in the electrolyte solution. Further, since the surface of stainless steel is covered with a passive film, there is a concern that the contact resistance between the stainless steel plate and the solution increases when the stainless steel plate is used as it is exposed to the electrolyte solution. For this reason, stainless steel cannot be easily adopted as the electrode material of the dye-sensitized solar cell. Patent Document 5 lists metals such as glass and stainless steel as substrates for the counter electrode (paragraph 0003), and Patent Document 6 discloses gold, silver, copper, platinum, nickel, titanium, tantalum, tungsten, Various corrosion resistant materials such as aluminum and stainless steel are listed (paragraph 0015). However, those documents do not show an example in which a metal material other than platinum is used for the electrode. In fact, a dye-sensitized solar cell that has succeeded in using stainless steel as an electrode material has not been seen yet.

As described above, a noble metal such as platinum is currently used as a metal material for an electrode of a dye-sensitized solar cell, which is accompanied by an increase in cost due to the use of an expensive noble metal material. In the type of electrode in which a “film” is formed of platinum, carbon black or other materials, there is room for improvement in electrical conductivity within the electrode.
In view of such a current situation, the present invention is an inexpensive electrode material that is composed of a metal material exhibiting excellent corrosion resistance in an electrolyte solution containing iodide ions of a dye-sensitized solar cell and ensures good electrical conduction. It is to provide.

In order to achieve the above object, in the present invention, in mass%, C: 0.15% or less, Si: 1.2% or less, Mn: 1.2% or less, P: 0.04% or less, S: 0.03% or less, Ni: 0.6% or less, Cr: 17-32%, Mo: 0.8-3%, Nb: 0-1%, Ti: 0-1%, Al: 0-0. 2%, N: 0.025% or less, O: 0.01% or less, B: 0 to 0.01%, further containing Cu: 0.01 to 1 % as necessary, the balance being Fe And a pigment comprising a metal plate having a composition that is an inevitable impurity and having a stainless steel plate exhibiting a ferrite phase structure on a substrate, and a platinum catalyst layer having an average film thickness of 5 to 50 nm formed on one surface of the substrate An electrode material for a sensitized solar cell is provided.

Further, by mass, C: 0.15% or less, Si: 4% or less, Mn: 2.5% or less, P: 0.045% or less, S: 0.03% or less, Ni: 3 to 28% Cr: 17 to 32%, Mo: 0.8 to 7%, Cu: 3.5% or less, Nb: 0 to 1%, Ti: 0 to 1%, Al: 0 to 0.1%, N: 0.3% or less, O: 0.01% or less, B: 0 to 0.01% , and if necessary, further contains Cu: 0.01 to 3.5 % , the balance being Fe and inevitable A metal having a composition which is an impurity and having a stainless steel plate having an austenite phase structure or an austenite + ferrite two-phase structure on a substrate, and a platinum catalyst layer having an average film thickness of 5 to 50 nm formed on one surface of the substrate An electrode material for a dye-sensitized solar cell comprising a plate is provided.

This electrode material is used in exposing the surface of the side having the catalyst layer to the electrolyte solution.

The electrode material of the dye-sensitized solar cell of the present invention has the following merits.
(1) Since it is based on a stainless steel plate, it has higher conductivity than transparent conductive films such as ITO, FTO, and TO.
(2) Since the catalyst layer is provided on the surface exposed to the electrolyte solution, the reaction on the electrode surface is promoted and the contact resistance with the liquid is reduced.
(3) Since the stainless steel of the substrate itself exhibits excellent corrosion resistance in the electrolyte solution used for the dye-sensitized solar cell, it is strong against the presence of defects and surface flaws in the catalyst layer.
(4) Since it is strong against the presence of defects and surface flaws in the catalyst layer, the thickness of the catalyst layer (amount of catalyst material such as platinum) can be minimized and the cost can be reduced.
(5) Since the stainless steel plate is the base, this electrode material itself has the function of a substrate and has higher strength than a conventional general glass substrate.
Therefore, the present invention contributes to the spread of dye-sensitized solar cells.

  In dye-sensitized solar cells that are currently being studied for practical use, an electrolyte solution containing iodide ions in an organic solvent is used. Therefore, the electrode material must be composed of a material that exhibits stable corrosion resistance for a long period of time and exhibits excellent corrosion resistance. Since the counter electrode 5 of FIG. 1A type and the photoelectrode 3 of FIG. 1B type do not need to transmit light, they are not transparent oxide-based materials such as ITO, FTO, TO, It is desirable to use a metal material with low electrical resistance. However, dye-sensitized solar cells in practical use tend to employ oxide-based materials such as ITO and FTO, whose reliability is known from past data, etc. for electrodes that may not be transparent. high. As for metal materials, little attention is paid to other than noble metal materials such as platinum.

  As a result of various studies, the inventors have been able to impart excellent corrosion resistance that hardly dissolves in an iodide-containing electrolyte solution using an organic solvent by including a certain amount of Cr and Mo in stainless steel. I found By utilizing this property, an electrode material for a dye-sensitized solar cell based on a stainless steel material can be realized. That is, a new application has been found in a stainless steel material having a specific composition.

Generally stainless steel chloride ion Cl ^- is to have a weak point in corrosion resistance to an aqueous solution containing, to improve its corrosion resistance the addition of increasing or Mo and Cr is to be effective. For example, in ferrite type SUS444 suitable for water heaters, Cr: 17% by mass or more and Mo: 1.75% by mass or more are ensured. Even in SUS316, which is a high corrosion resistance austenitic general-purpose steel grade, Cr: 16% by mass. As mentioned above, Mo: Content of 2 mass% or more is ensured. However, there are surprisingly few reports on the corrosion resistance of stainless steel against iodide ions. The reason for this is that there is almost no environment exposed to iodide ions in nature or in daily life. In particular, regarding the iodide ion-containing electrolyte solution when the solvent is not water but an organic substance, the relationship between the composition of stainless steel and the corrosion resistance is hardly grasped. It has been found that SUS304, which is a general-purpose steel type, corrodes severely with respect to the electrolyte solution, and the application of stainless steel materials for electrode applications of dye-sensitized solar cells has been avoided. This was a factor that motivated me to make a detailed examination.

  As a result of detailed studies, the inventors have found that when the Cr content in the stainless steel material is 17% by mass or more and the Mo content is 0.8% by mass or more, the iodine applied to the dye-sensitized solar cell. It has been found that excellent corrosion resistance that hardly dissolves in a fluoride-containing electrolyte solution is exhibited. As described above, even when the application is a daily hot water environment, in order to give the stainless steel sufficient corrosion resistance, it is necessary to add a relatively large amount of Mo, for example, 1.75% by mass or more. is there. Compared to this, it has been clarified that the corrosion resistance of the dye-sensitized solar cell in which iodide ions are present in the organic solvent to the electrolyte solution is remarkably improved from a smaller Mo addition range. Moreover, this tendency is not significantly affected by steel types such as austenitic and ferritic, and is less affected by other additive elements. This point is very different from the corrosion resistance tendency of stainless steel against chloride ions. Therefore, it is considered that the mechanism for improving corrosion resistance caused by Cr, Mo and the like cannot be equated with the case of chloride ions.

  In the present invention, stainless steels having the following composition ranges are applied to each of the ferritic steel types and the austenitic and austenite + ferrite two-phase steel types. Unless otherwise specified, “%” with respect to the alloy element content means “mass%”.

[Ferrite]
“C: 0.15% or less, Si: 1.2% or less, Mn: 1.2% or less, Cr: 17 to 32%, Mo: 0.8 to 3%, N: 0.025% or less, balance A composition of “Fe” can be employed.
Among these, C, Si, Mn, and N are elements that are unavoidable in the melting process at the mass production site of stainless steel, and are allowed to be contained within the above range. However, considering various properties such as manufacturability, for example, C: 0.01% or less, Si: 0.5% or less or 0.3% or less, Mn: 0.5% or less or 0.3% or less, N: It is effective to control to 0.020% or less.

  When the Cr content is less than 17% or the Mo content is less than 0.8%, it is excellent that the material hardly dissolves in the iodide-containing electrolyte solution applied to the dye-sensitized solar cell. It becomes difficult to stably obtain corrosion resistance. In order to further improve the reliability, it is preferable to contain 18% or more of Cr and 1% or more of Mo. However, when the content of Cr or Mo is excessively increased, the adverse effects such as the manufacturability are remarkable. For this reason, the Cr content is desirably 32% or less, and more preferably 30% or less. The Mo content is preferably 3% or less, and more preferably 2% or less.

  As other elements, a composition containing Cu: 1% or less, for example, 0.01 to 1% can be adopted. In this case, the Cu content may be more severely controlled, for example, within a range of 0.1% or less.

The remainder other than these may be substantially composed of Fe, but the following elements can be generally listed as elements that are allowed to be mixed into stainless steel. The allowable range is also shown.
P: 0.04% or less, S: 0.03% or less, preferably 0.005% or less, Ni: 0.6% or less, preferably 0.25% by mass or less, Nb: 1% or less, preferably 0.5% Ti: 1% or less, preferably 0.3% or less, Al: 0.2% or less, O: 0.01% or less, preferably 0.005% or less, B: 0.01% or less, V: 0.00% 3% or less, Zr: 0.3% or less, Ca, Mg, Co, and REM (rare earth elements): 0.1% or less in total

The following can be mentioned when the concrete composition of the ferritic steel type containing said tolerance element is illustrated.
(1) By mass%, C: 0.15% or less, Si: 1.2% or less, Mn: 1.2% or less, P: 0.04% or less, S: 0.03% or less, Ni: 0 0.6% or less, Cr: 17 to 32%, Mo: 0.8 to 3%, Nb: 0 to 1%, Ti: 0 to 1%, Al: 0 to 0.2%, N: 0.025% Hereinafter, O: 0.01% or less, B: 0 to 0.01%, the balance being Fe and inevitable impurities (2) mass%, C: 0.15% or less, Si: 1.2% or less Mn: 1.2% or less, P: 0.04% or less, S: 0.03% or less, Ni: 0.6% or less, Cr: 17-32%, Mo: 0.8-3%, Cu 1% or less, Nb: 0 to 1%, Ti: 0 to 1%, Al: 0 to 0.2%, N: 0.025% or less, O: 0.01% or less, B: 0 to 0.00. 01% with the balance being Fe and inevitable impurities

  Here, the lower limit 0% of Nb, Ti, Al, and B is the case where the content of the element is below the measurement limit in a normal analysis method in the steelmaking process (the austenite system, austenite + ferrite two-phase system described later) The same in).

[Austenitic, austenitic + ferrite two-phase]
“C: 0.15% or less, Si: 4% or less, Mn: 2.5% or less, Ni: 3 to 28%, Cr: 17 to 32%, Mo: 0.8 to 7%, N: 0.00. A composition of 3% or less and the balance substantially Fe "can be employed.
Among these, C, Si, Mn, and N are elements that are unavoidable in the melting process at the mass production site of stainless steel, and are allowed to be contained within the above range. However, considering various properties such as manufacturability, for example, C: 0.08% or less or 0.03% or less, Si: 1% or less or 0.6% or less, Mn: 2% or less, N: 0.00 It is effective to control to 03% or less or 0.01% or less.
In the case of an austenitic system, Ni is contained in an amount of 7% or more, preferably 10% or more.

  When the Cr content is less than 17% or the Mo content is less than 0.8%, the material is dissolved in the iodide-containing electrolyte solution applied to the dye-sensitized solar cell as in the case of the ferrite type. It becomes difficult to stably obtain excellent corrosion resistance that hardly occurs. In order to further improve the reliability, it is preferable to contain 2% or more of Mo. However, when the content of Cr or Mo is excessively increased, the adverse effects such as the manufacturability are remarkable. For this reason, the Cr content is desirably 32% or less, and more preferably 30% or less. The Mo content is preferably 7% or less, and more preferably 4% or less.

  As other elements, a composition containing Cu: 3.5% or less, for example, 0.01 to 3.5% can be employed. In this case, the Cu content may be more severely controlled, for example, within a range of 1% or less, or 0.5% or less.

The remainder other than these may be substantially composed of Fe, but the following elements can be generally listed as elements that are allowed to be mixed into stainless steel. The allowable range is also shown.
P: 0.045% or less, S: 0.03% or less, preferably 0.005% or less, Nb: 1% or less, preferably 0.5% or less, Ti: 1% or less, preferably 0.3% or less, Al : 0.1% or less, preferably 0.01% or less, O: 0.01% or less, preferably 0.005% or less, B: 0.01% or less, V: 0.3% or less, Zr: 0.3 % Or less, Ca, Mg, Co and REM (rare earth elements): 0.1% or less in total

Examples of the specific composition of the austenitic steel types including the above-mentioned allowable elements and the austenite + ferrite two-phase steel types include the following.
(1) By mass%, C: 0.15% or less, Si: 4% or less, Mn: 2.5% or less, P: 0.045% or less, S: 0.03% or less, Ni: 3 to 28 %, Cr: 17 to 32%, Mo: 0.8 to 7%, Nb: 0 to 1%, Ti: 0 to 1%, Al: 0 to 0.1%, N: 0.3% or less, O : 0.01% or less, B: 0 to 0.01%, the balance being Fe and inevitable impurities (2) mass%, C: 0.15% or less, Si: 4% or less, Mn: 2. 5% or less, P: 0.045% or less, S: 0.03% or less, Ni: 3 to 28%, Cr: 17 to 32%, Mo: 0.8 to 7%, Cu: 3.5% or less Nb: 0 to 1%, Ti: 0 to 1%, Al: 0 to 0.1%, N: 0.3% or less, O: 0.01% or less, B: 0 to 0.01% , The balance is Fe and inevitable impurities

  The steel whose composition is adjusted as described above may be a steel plate having a necessary thickness by a general stainless steel plate manufacturing process. Using this as a substrate, a catalyst layer is provided on the surface on one side. Examples of the catalyst substance include transition metals having high catalytic activity such as platinum and palladium, and organometallic complexes such as carbon black and porphyrin. As a method for forming a catalyst layer using platinum, known methods such as sputter coating and electroplating can be used. Sputter coating is suitable in terms of forming a platinum film that is as thin and uniform as possible. In this case, the average thickness of the catalyst layer may be controlled in the range of about 5 to 100 nm. For example, it can be as thin as 5 to 50 nm. In the case of carbon black, the catalyst layer can be formed by a method of applying and drying a paste mixed with a binder. This metal plate having a catalyst layer on the surface is a member constituting the “counter electrode” or “photoelectrode” of the dye-sensitized solar cell, with the surface on the side where the catalyst layer is formed in contact with the electrolyte solution. used.

  In FIG. 2, the structural example of the dye-sensitized solar cell using the electrode material of this invention which consists of said metal plate is shown typically. FIG. 2A shows a conventional dye-sensitized solar cell of the type shown in FIG. 1A in which the substrate 4 and the counter electrode 5 are changed to a counter electrode 30 made of the electrode material of the present invention. FIG. 2B shows a conventional dye-sensitized solar cell of the type shown in FIG. 1B in which the substrate 4 and the photoelectrode 3 are replaced with a photoelectrode 40 made of the electrode material of the present invention. is there.

Various stainless steels having the compositions shown in Table 1 were melted, and cold-rolled annealed steel sheets (2D finishing materials) having a thickness of 0.28 to 0.81 mm were manufactured by a general stainless steel sheet manufacturing process. In Table 1, in the structure column, “α” means ferrite and “γ” means austenite. The hyphen “-” in Cu, Nb, Ti, and Al means that it is below the measurement limit in a normal analysis method at a steelmaking site.
By observing the structure of each steel sheet, it has been confirmed that the ferrite type matrix has a ferrite phase and the austenitic type matrix has an austenitic phase.

In order to evaluate the corrosion resistance of the stainless steel plate itself as a base material, a test piece of 35 × 35 mm was cut out from each test material, and the surface (including the end face) was finished by # 600 dry emery polishing. did. In addition, in order to confirm the corrosion resistance in a state where a catalyst layer was formed on some test pieces, platinum was further coated on one side with an average film thickness of about 50 nm or 10 nm by sputtering coating.
As a test solution simulating an electrolyte solution of a dye-sensitized solar cell, a solution prepared by dissolving iodine I ₂ : 0.05 mol / L and lithium iodide LiI: 0.5 mol / L in an acetonitrile solvent was prepared.

  10 mL of the test solution was placed in a Teflon (registered trademark) container, and the corrosion resistance test piece was immersed in the solution. The container was covered to suppress the volatilization of the solvent. This container was hold | maintained in the 80 degreeC thermostat, and the test piece was taken out after 500-hour progress from the immersion start. For each steel type, the number of samples was n = 3.

  About each test piece after 500-hour immersion, the weight change (The test piece weight after immersion-Initial test piece weight) was measured. The lowest value (that is, the largest weight loss value) among the weight change values of n = 3 was adopted as the result of the weight change of the steel type. Moreover, the surface was visually observed and the external appearance was investigated. Also in this case, the appearance of the test piece having the most severe degree of corrosion among n = 3 was adopted as the grade of the steel type. Except for the steel type in which the overall corrosion or end face corrosion was recognized in the appearance after immersion for 500 hours, the specimen after observation was again subjected to the above immersion test. At that time, a new test solution was used. The test piece was taken out when the total immersion time from the initial state was 1000 h, and the weight change and appearance were examined in the same manner as described above.

The value of the weight change after the immersion test means that the larger the value on the negative side, the more the amount of dissolution due to corrosion. When the total weight change after the 1000 h immersion test was on the plus side of −0.05 g / m ² , it was evaluated that the dissolution due to corrosion hardly proceeded, and this was determined to be acceptable.
As for the appearance, those having no dissolved part and no rusting were indicated as “no abnormality”, and those evaluated as “no abnormality” after the 1000 h immersion test were determined to be acceptable.
The results are shown in Table 2.

  As can be seen from Tables 1 and 2, in the present invention containing Cr: 17% or more and Mo: 0.8% or more, in the stainless steel sheet itself (hereinafter referred to as “base sample”) as a base, Almost no dissolution due to corrosion was observed in the iodide ion-containing electrolyte solution, and excellent corrosion resistance was observed with no occurrence of spot rust. In addition, in a sample in which a thin platinum film such as 50 nm or 10 nm is formed on the stainless steel plate, the corrosion resistance at the site where the platinum film is not formed (stainless steel surface) dominates the corrosion resistance of the entire sample, and the base of the same steel type Although the corrosion resistance evaluation was the same as that of the sample, the corrosion resistance at the site where the platinum film was formed was not inferior to the corrosion resistance of the exposed surface of the stainless steel. Therefore, it is thought that the electrode material which consists of a metal plate which uses each stainless steel kind of the example of this invention has sufficient durability requested | required of the electrode of a dye-sensitized solar cell.

A test piece of 100 × 100 mm was cut out from the stainless steel plate prepared in Example 1, and the surface was finished by # 600 dry emery polishing. Some test pieces were further coated with platinum with an average film thickness of about 50 nm or 10 nm in the same manner as in Example 1. For reference, Nesa glass (a transparent conductive film of TO (tin oxide) deposited on a glass substrate) was prepared.
For these surfaces (platinum-coated samples were platinum surfaces, and nesa glass was conductive film surfaces), the surface resistivity was measured by a four-probe method using a low resistivity meter (manufactured by Mitsubishi Chemical Corporation, Lorester GP). The number of samples was n = 3, and an average value was adopted.
The results are shown in Table 3.

  As can be seen in Table 3, the metal material based on stainless steel has a very low surface electrical resistance compared to the oxide-based conductive film. Even with the platinum coating, a surface resistivity substantially reflecting the conductivity of the underlying stainless steel plate was obtained. Therefore, the electrode material of the present invention made of a metal plate having a structure in which a catalyst layer is formed on the surface of a stainless steel plate is more electrically conductive than a conventional electrode material made of a “film” formed on a non-conductive substrate. It can be seen that the sex is dramatically improved. In addition, in the electrode where the surface of the stainless steel plate is directly exposed to the electrolyte, there is a concern that the contact resistance with the liquid is increased by the passive film, but this problem is also solved by providing platinum or other catalyst layer on the surface. The

The figure which showed typically the structure of the conventional dye-sensitized solar cell. The figure which showed typically the structural example of the dye-sensitized solar cell using the electrode material of this invention.

Explanation of symbols

1 counter 40 present invention comprising the electrode material of the solar cell 2 transparent substrate 3 photoelectrode 4 substrate 5 counter 6 photoelectric conversion layer 7 TiO ₂ particles 8 Ru dye 9 electrolytic solution 10 loads 20 the incident light 21 stainless steel 22 catalyst layer 30 present invention Photoelectrode made of any electrode material

Claims (4)

C: 0.15% or less, Si: 1.2% or less, Mn: 1.2% or less, P: 0.04% or less, S: 0.03% or less, Ni: 0.6% Hereinafter, Cr: 17 to 32%, Mo: 0.8 to 3%, Nb: 0 to 1%, Ti: 0 to 1%, Al: 0 to 0.2%, N: 0.025% or less, O : 0.01% or less, B: 0 to 0.01%, with the balance being Fe and inevitable impurities, with a stainless steel plate having a ferrite phase structure on the substrate, the surface on one side of the substrate An electrode material for a dye-sensitized solar cell comprising a metal plate on which a platinum catalyst layer having an average film thickness of 5 to 50 nm is formed. The electrode material for a dye-sensitized solar cell according to claim 1, wherein the stainless steel plate further has a composition containing Cu: 0.01 to 1 % . C: 0.15% or less, Si: 4% or less, Mn: 2.5% or less, P: 0.045% or less, S: 0.03% or less, Ni: 3 to 28%, Cr : 17-32%, Mo: 0.8-7%, Nb: 0-1%, Ti: 0-1%, Al: 0-0.1%, N: 0.3% or less, O: 0.3. 01% or less, B: 0 to 0.01%, with the balance being Fe and inevitable impurities, and having a stainless steel plate having an austenite phase structure or an austenite + ferrite two phase structure on the substrate. The electrode material of the dye-sensitized solar cell which consists of a metal plate in which the platinum catalyst layer with an average film thickness of 5-50 nm is formed in the surface of one side. The electrode material for a dye-sensitized solar cell according to claim 3, wherein the stainless steel plate further has a composition containing Cu: 0.01 to 3.5 % .

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