JP2013122874A - Photoelectric conversion element, method for manufacturing the same, electronic device, counter electrode for photoelectric conversion element, and building - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a counter electrode excellent in electrolyte resistance and conductivity, and capable of being manufactured at low cost.SOLUTION: A dye-sensitized photoelectric conversion element 10 includes an electrolyte layer 8 filled between a porous electrode 7 on which a photosensitizing dye is adsorbed, and a counter electrode 1. The counter electrode 1 for a dye-sensitized photoelectric conversion element includes a metal substrate 2, a catalyst layer 3, and a conductive diamond-like carbon film 4. The metal substrate 2 and the catalyst layer 3 are in contact with opposite sides of the conductive diamond-like carbon film 4.

Description

  The present disclosure relates to a photoelectric conversion element, a manufacturing method thereof, an electronic device, a counter electrode for the photoelectric conversion element, and a building. For example, a photoelectric conversion element suitable for use in a dye-sensitized solar cell, a manufacturing method thereof, and the photoelectric conversion element are used. The present invention relates to a counter electrode for a photoelectric conversion element suitable for use in an electronic device and a dye-sensitized solar cell, and a building using the photoelectric conversion element.

Solar cells, which are photoelectric conversion elements that convert sunlight into electrical energy, use sunlight as an energy source, and therefore have very little influence on the global environment, and are expected to become more widespread.
As a conventional solar cell, a crystalline silicon solar cell using single crystal or polycrystalline silicon and an amorphous silicon solar cell are mainly used.

  On the other hand, the dye-sensitized solar cell proposed by Gretzell et al. In 1991 can obtain high photoelectric conversion efficiency, and unlike a conventional silicon-based solar cell, it does not require a large-scale device for production, and has a low It is attracting attention because it can be manufactured at low cost (for example, see Non-Patent Document 1).

This dye-sensitized solar cell generally has a porous electrode made of titanium oxide (TiO ₂ ) or the like combined with a photosensitizing dye and a counter electrode made of platinum (Pt) or the like facing each other. In which an electrolyte layer made of an electrolytic solution is filled. As the electrolytic solution, a solution obtained by dissolving an electrolyte containing an oxidizing / reducing species such as iodine (I) or iodide ion (I ⁻ ) in a solvent is often used.

  In general, the solar cell is required to have stable photoelectric conversion characteristics over a long period of time. In particular, a dye-sensitized solar cell generally contains a liquid electrolyte component as a constituent element. For this reason, in order to obtain stable photoelectric conversion characteristics over a long period of time, characteristic deterioration due to corrosion by the electrolyte solution is an important issue. Therefore, conventionally, platinum has been mainly used as a counter electrode of a dye-sensitized solar cell because it has both excellent catalytic action and corrosion resistance to an electrolyte. Platinum is generally excellent in catalytic activity, corrosion resistance, conductivity and the like. However, since platinum, which is a material, is scarce and expensive in terms of resources, using the platinum layer as a counter electrode has a problem that the material cost is very high.

  In order to solve this problem, in recent years, the development of dye-sensitized solar cells that can be manufactured at low cost and has excellent long-term stability by forming a counter electrode with a metal substrate using a metal that is lower in cost than platinum. Has been done.

  For the metal substrate constituting the counter electrode, a titanium-based material having properties excellent in electrical conductivity and corrosion resistance against an electrolyte is generally used. However, since titanium-based materials are also expensive, the problem of high material costs still remains. In order to solve this problem, it is necessary to apply a low-priced general-purpose metal material such as an aluminum (Al) system or a stainless steel (SUS) system in place of the titanium-based material to the metal substrate.

  However, low-priced general-purpose metal materials such as aluminum (Al) and stainless steel (SUS) have excellent properties in terms of electrical conductivity, but generally have low corrosion resistance against electrolytes, and are the opposite metal. It does not have performance that can withstand practical use as a substrate. Therefore, when a metal substrate is constituted by the general-purpose metal material, it is necessary to improve the corrosion resistance by the electrolyte while ensuring the electrical conductivity. Therefore, a proposal has been made to improve the corrosion resistance of the metal substrate against the electrolyte while ensuring electrical conductivity by performing some treatment on the surface of the metal substrate in contact with the electrolyte (for example, Patent Documents 1 and 2). reference.).

  Among them, a proposal has been made that the corrosion resistance and chemical resistance of a dye-sensitized solar cell are improved when the counter electrode catalyst layer is made of conductive diamond-like carbon (DLC) (for example, Patent Document 3).

JP 2006-318770 A JP 2008-257948 A JP 2005-293863 A

Nature, 353, p.737-740,1991

However, although the dye-sensitized solar cell proposed in this document is excellent in the corrosion resistance against the electrolyte of the counter electrode, it cannot be said that the photoelectric conversion performance and the durability with time are high.
Therefore, a problem to be solved by the present disclosure is to provide a counter electrode for a dye-sensitized photoelectric conversion element that can be manufactured at low cost and has excellent photoelectric conversion performance and durability performance over time.

  Moreover, the other subject which this indication tends to solve is providing the photoelectric conversion element using the above counter electrodes for photoelectric conversion elements.

  Furthermore, still another problem to be solved by the present disclosure is to provide a high-performance electronic device using the excellent photoelectric conversion element as described above.

  Moreover, the other subject which this indication tends to solve is providing the building using the above outstanding photoelectric conversion elements.

In order to solve the above problems, the present disclosure provides:
A porous electrode;
With the counter electrode,
Having an electrolyte layer between the porous electrode and the counter electrode;
The counter electrode is
A metal substrate;
A conductive diamond-like carbon film provided on the metal substrate;
It is a photoelectric conversion element having a catalyst layer provided on the conductive diamond-like carbon film.

In addition, this disclosure
A metal substrate;
A conductive diamond-like carbon film provided on the metal substrate;
And a catalyst layer provided on the conductive diamond-like carbon film.

In addition, this disclosure
A porous electrode;
With the counter electrode,
When manufacturing a photoelectric conversion element having an electrolyte layer between the porous electrode and the counter electrode,
A conductive diamond-like carbon film is formed on a metal substrate,
This is a method for producing a photoelectric conversion element, wherein the counter electrode is formed by forming a catalyst layer on the conductive diamond-like carbon film.

In addition, this disclosure
Having at least one photoelectric conversion element;
The photoelectric conversion element is
A porous electrode;
With the counter electrode,
Having an electrolyte layer between the porous electrode and the counter electrode;
The counter electrode is
A metal substrate;
A conductive diamond-like carbon film provided on the metal substrate;
It is an electronic device which is a photoelectric conversion element having a catalyst layer provided on the conductive diamond-like carbon film.

In addition, this disclosure
Having at least one photoelectric conversion element;
The photoelectric conversion element is
A porous electrode;
With the counter electrode,
Having an electrolyte layer between the porous electrode and the counter electrode;
The counter electrode is
A metal substrate;
A conductive diamond-like carbon film provided on the metal substrate;
The building is a photoelectric conversion element having a catalyst layer provided on the conductive diamond-like carbon film.

In the present disclosure, the porous electrode is composed of fine particles made of a semiconductor. The semiconductor preferably comprises titanium oxide (TiO ₂ ), especially anatase TiO ₂ .

As the porous electrode, a so-called core-shell structured fine particle may be used. As the porous electrode, preferably used is one constituted by fine particles comprising a core made of metal and a shell made of a metal oxide surrounding the core. When such a porous electrode is used, when an electrolyte layer is provided between the porous electrode and the counter electrode, the electrolyte in the electrolyte layer does not come into contact with the metal / metal oxide fine metal core. Therefore, dissolution of the porous electrode by the electrolyte can be prevented. For this reason, gold (Au), silver (Ag), copper (Cu), or the like, which has been difficult to use in the past and has a large surface plasmon resonance effect, is used as the metal constituting the metal / metal oxide fine particle core. Thus, the effect of surface plasmon resonance can be sufficiently obtained in photoelectric conversion. In addition, an iodine-based electrolyte can be used as the electrolyte of the electrolytic solution. Platinum (Pt), palladium (Pd), etc. can also be used as the metal constituting the core of the metal / metal oxide fine particles. As the metal oxide constituting the shell of the metal / metal oxide fine particles, a metal oxide that does not dissolve in the electrolyte to be used is used, and is selected as necessary. Such a metal oxide is preferably at least one selected from the group consisting of titanium oxide (TiO ₂ ), tin oxide (SnO ₂ ), niobium oxide (Nb ₂ O ₅ ), and zinc oxide (ZnO). However, the present invention is not limited to these. For example, a metal oxide such as tungsten oxide (WO ₃ ) or strontium titanate (SrTiO ₃ ) can be used. The particle size of the fine particles is appropriately selected, but is preferably 1 nm or more and 500 nm or less. The particle diameter of the core of the fine particles is also appropriately selected, but is preferably 1 nm or more and 200 nm or less.

  An electrolyte solution is typically used as a constituent of the electrolyte layer. A conventionally well-known thing can be used as electrolyte solution, It selects as needed. From the viewpoint of preventing volatilization of the electrolytic solution, a low-volatile electrolytic solution, for example, an ionic liquid electrolytic solution using an ionic liquid as a solvent is preferably used. A conventionally well-known thing can be used as an ionic liquid, and it selects as needed.

  Moreover, you may comprise an electrolyte layer with the porous membrane containing electrolyte solution. By doing so, since the electrolyte layer becomes solid, it is possible to prevent the electrolyte from leaking when the photoelectric conversion element is damaged. In addition, incident light that has passed through the porous electrode and entered the photoelectric conversion element is scattered by the porous film that constitutes the electrolyte layer and is incident on the porous electrode again. Therefore, the incident light is collected by the porous electrode. The rate is high. Thereby, a photoelectric conversion element with high short circuit current density and photoelectric conversion efficiency is realizable. Further, since the electrolyte layer can be constituted by a porous film containing an electrolytic solution, the electrolytic solution can be substantially handled as a membrane, and the handling of the electrolytic solution becomes extremely simple. For this reason, a dye-sensitized photoelectric conversion element having excellent characteristics can be easily realized.

  Various types of porous membranes can be used as the electrolyte layer, and the structure and material are selected as necessary. As this porous film, an insulating material is used. Even if this insulating porous film is made of an insulating material, for example, the surface of the void portion of the porous film made of a conductive material is used. Even if the insulator is made into an insulator, the surface of the void portion may be coated with an insulating film. This porous film may be made of an organic material or an inorganic material. As this porous film, various non-woven fabrics are preferably used, and as the material, for example, various organic polymer compounds such as polyolefin, polyester, cellulose and the like can be used, but are not limited thereto. Absent. The porosity of the porous film is selected as necessary, but the porosity (actual porosity) in the state provided between the porous electrode and the counter electrode is preferably 50% or more. This actual porosity is preferably selected from 80% to less than 100% from the viewpoint of obtaining high photoelectric conversion efficiency.

  Electronic devices may be basically any type, including both portable and stationary types, but specific examples include mobile phones, mobile devices, robots, personal computers. , In-vehicle equipment, various home appliances. In this case, the photoelectric conversion element is a solar cell used as a power source for these electronic devices, for example.

  The counter electrode for a photoelectric conversion element is an electrode provided on the positive electrode side of the photoelectric conversion element.

  The photoelectric conversion element is most typically configured as a solar cell. The photoelectric conversion element may be other than a solar cell, for example, an optical sensor or the like, but is not limited thereto. Basically, the photoelectric conversion element is an element that has a negative electrode and a positive electrode and is driven by light. Any thing is acceptable.

  Buildings are typically large buildings such as buildings and condominiums, but are not limited to this. Basically, any building having an outer wall surface may be used. Also good. Specific examples of the building include a detached house, an apartment, a station building, a school building, a government building, a stadium, a stadium, a hospital, a church, a factory, a warehouse, a shed, a garage, and a bridge. The structure is preferably a built structure having two window parts (for example, glass windows) or a daylighting part, but the building is not limited to those mentioned above.

  Among photoelectric conversion elements provided in buildings and / or photoelectric conversion element modules in which a plurality of photoelectric conversion elements are electrically connected, those provided in a window or daylighting section are sandwiched between two transparent plates However, it is preferable to fix and configure as necessary. Typically, the photoelectric conversion element and / or the photoelectric conversion element module is assembled between two glass plates and fixed as necessary. Is done.

  According to the present technology, by using a new counter electrode having a conductive diamond-like carbon film between a metal substrate and a catalyst layer for a photoelectric conversion element, a photoelectric conversion device having excellent photoelectric conversion performance and durability over time. The conversion element can be manufactured at low cost. Further, by using this photoelectric conversion element, a high-performance electronic device or the like can be realized.

It is sectional drawing which shows the counter electrode for dye-sensitized photoelectric conversion elements by 1st Embodiment. It is sectional drawing which shows the dye-sensitized photoelectric conversion element by 2nd Embodiment. It is a basic diagram which showed the current-voltage output characteristic of the dye-sensitized photoelectric conversion element. It is a basic diagram which showed the current-voltage output characteristic of the dye-sensitized photoelectric conversion element. It is a basic diagram which showed transition of the value of the open circuit voltage with respect to the elapsed time of the dye-sensitized photoelectric conversion element in a reliability acceleration test. It is a basic diagram which showed transition of the value of the photoelectric conversion efficiency with respect to the elapsed time of the dye-sensitized photoelectric conversion element in a reliability acceleration test. It is a basic diagram which showed the current-voltage output characteristic of the dye-sensitized photoelectric conversion element. It is sectional drawing which shows the counter electrode for dye-sensitized photoelectric conversion elements by 3rd Embodiment. It is sectional drawing which shows the dye-sensitized photoelectric conversion element by 4th Embodiment. It is a basic diagram which showed the current-voltage output characteristic of the dye-sensitized photoelectric conversion element. It is a basic diagram which showed the current-voltage output characteristic of the dye-sensitized photoelectric conversion element. It is a basic diagram which showed the current-voltage output characteristic of the dye-sensitized photoelectric conversion element. It is a basic diagram which showed transition of the value of the photoelectric conversion efficiency with respect to the elapsed time of the dye-sensitized photoelectric conversion element in a reliability acceleration test. It is sectional drawing which shows an example of the conventional common dye-sensitized photoelectric conversion element. It is a basic diagram which showed the electric current-voltage output characteristic of the dye-sensitized photoelectric conversion element in a reliability acceleration test. It is a basic diagram which showed the measurement result of the open circuit voltage with respect to the elapsed time of the dye-sensitized photoelectric conversion element in a reliability acceleration test.

  The present inventors have intensively studied to solve the above-described problems. In the course of the research, it was found that the deterioration with time of photoelectric conversion efficiency in the dye-sensitized photoelectric conversion element is particularly remarkable in the initial stage of power generation from the start of power generation to a certain time. The outline will be described below.

FIG. 14 is a cross-sectional view of a main part showing a conventional dye-sensitized photoelectric conversion element 100.
As shown in FIG. 14, in this dye-sensitized photoelectric conversion element 100, a transparent electrode 106 that is an FTO layer is provided on one main surface of a transparent substrate 105, and the transparent electrode 106 is composed of a sintered body of TiO _2. A porous electrode 107 is provided. One or more kinds of photosensitizing dyes (not shown) are bonded to the porous electrode 107. On the other hand, a catalyst layer 103 is provided on one main surface of a metal substrate 102 that is a titanium substrate, thereby constituting a counter electrode 101. The porous electrode 107 and the counter electrode 101 are filled with an electrolyte layer 108 made of an electrolytic solution using redox species of I ⁻ / I ₃ ⁻ as a redox pair, and the transparent substrate 105 and the metal substrate 102 The outer periphery is sealed with a sealing body 109.

  When light enters the porous electrode 107, the dye-sensitized photoelectric conversion element 100 operates as a battery having the transparent electrode 106 as a negative electrode and the counter electrode 101 as a positive electrode.

  In order to measure the change in the power generation output efficiency of the dye-sensitized photoelectric conversion element 100 over time, the present inventors performed a reliability acceleration test. In the reliability acceleration test, the dye-sensitized photoelectric conversion element 100 immediately after production is placed in a thermostatic chamber of 60 degrees or more and 85 degrees or less, and the dye-sensitized photoelectric conversion element 100 is irradiated with pseudo-sunlight having a certain intensity. A method of holding for a certain time was adopted.

FIG. 15 shows the current-voltage output characteristics (IV output characteristics) of the dye-sensitized photoelectric conversion element 100 immediately before being put into the thermostat in the reliability acceleration test, that is, immediately before the start of measurement, and the reliability acceleration test. It is a basic diagram which compared with the IV output characteristic 258 hours after a measurement start.
As shown in FIG. 15, the IV output characteristics after 258 hours from the start of measurement increase the value of the short-circuit current density that is the maximum value of the output current, but the value of the open-circuit voltage that is the maximum value of the output voltage is Decrease significantly. From this, it is considered that the deterioration over time of the power generation output efficiency of the dye-sensitized photoelectric conversion element 100 is mainly due to the decrease in the value of the output voltage. Particular attention was paid to the value of the open circuit voltage, which is the maximum value of the power generation voltage of the element 100, and further research was conducted.

FIG. 16 is a schematic diagram showing the measurement result of the open-circuit voltage value with respect to the elapsed time in the reliability acceleration test, normalized with the open-circuit voltage value immediately before the start of measurement being 100.
As shown in FIG. 16, the measured value of the open circuit voltage is 90% or less of the initial measurement during the period from the start of measurement to the lapse of 100 hours, and falls sharply. As a result of the diligent research on this factor, the following multiple factors emerged.

  The first factor is considered to be a decrease in the catalyst performance of the counter electrode 101 and an increase in the surface resistance value. This is attributed to deterioration with the passage of time due to a change in the material constituting the counter electrode 101, and this change is considered to be caused by a reaction with the electrolytic solution in the electrolyte layer 108 or the like.

  A possible second factor is an increase in DC resistance between the positive and negative electrodes. This includes an increase in contact resistance between the transparent electrode 106 and the porous electrode 107, an increase in contact resistance between the metal substrate 102 and the catalyst layer 103, an increase in resistance due to a change in the electrolyte solution in the electrolyte layer 108, and the like. It is thought to be caused by.

  It is considered that the increase in contact resistance described above is caused by the alteration of the contact interface in each layer by the electrolytic solution. Further, the alteration of the electrolyte solution in the electrolyte layer 108 is caused by the sealing ability of the sealing body 109 that seals the electrolyte layer 108 or the substance that constitutes the counter electrode 101 elutes into the electrolyte solution due to the above reaction or the like. It is thought that it is caused by lowering. In particular, the decrease in the sealing capability of the sealing body 109 causes intrusion of moisture into the electrolyte layer 108, volatilization or leakage of the electrolyte solution from the electrolyte layer 108, and the like. It has a great influence on the alteration of This deterioration over time of the sealing body 109 is considered to occur mainly at the adhesion interface of the sealing body 109. In particular, when the sealing body 109 and the metal substrate 102 constituting the counter electrode 101 are bonded and the electrolyte layer 108 is sealed, the deterioration of the sealing performance of the sealing body 109 is very large with time. It will be a thing. This is presumably because the bonding force between the metal substrate 102 and the sealing body 109 is originally weak, and the bonding force is further weakened with time. Such deterioration with time of the sealing body 109 is considered to be caused because the bonding between the surface layer of the metal substrate 102 and the sealing body 109 is replaced by a bond with water molecules. Such an increase in direct current resistance causes not only a decrease in open circuit voltage but also a decrease in fill factor (FF), thereby significantly reducing the photoelectric conversion efficiency.

  The present inventors have further researched to solve these newly discovered problems. In the process, when the counter electrode of the dye-sensitized photoelectric conversion element is configured by providing a conductive diamond rank carbon film that is a conductive intermediate layer between the catalyst layer and the metal substrate, the above-described problems can be solved, The present inventors have found that the deterioration of the performance of the dye-sensitized photoelectric conversion element over time can be effectively suppressed, and have come up with the present technology.

Hereinafter, modes for carrying out the invention (hereinafter referred to as “embodiments”) will be described. The description will be made in the following order.
1. First Embodiment (Counter Electrode for Dye-sensitized Photoelectric Conversion Element and Method for Producing the Same)
2. Second Embodiment (Dye-sensitized photoelectric conversion element and manufacturing method thereof)
3. Third Embodiment (Counter Electrode for Dye-sensitized Photoelectric Conversion Element and Method for Producing the Same)
4). Fourth Embodiment (Dye-sensitized photoelectric conversion element and method for producing the same)
5. Fifth embodiment (photoelectric conversion element and manufacturing method thereof)

<1. First Embodiment>
[Counter electrode for dye-sensitized photoelectric conversion element]
First, the first embodiment will be described.
FIG. 1 is a cross-sectional view of an essential part showing a counter electrode 1 for a dye-sensitized photoelectric conversion element according to a first embodiment.
As shown in FIG. 1, the counter electrode 1 for dye-sensitized photoelectric conversion element (hereinafter referred to as counter electrode 1) is provided by laminating a conductive diamond-like carbon film 4 so as to cover the entire main surface of the metal substrate 2. The catalyst layer 3 is provided on at least a part of the surface of the conductive diamond-like carbon film 4. The conductive diamond-like carbon film 4 is in close contact with the metal substrate 2 and the catalyst layer 3, and these constitute the counter electrode 1.

  The material constituting the metal substrate 2 may be basically any metal as long as it is a metal, but is preferably a metal having excellent conductivity, a low thermal expansion coefficient, and good thermal conductivity. . Specific examples of the metal include a simple metal, an alloy, and a metal compound. If the metal is simple, for example, gold (Au), silver (Ag), copper (Cu), titanium (Ti), zinc ( Zn), tin (Sn), iron (Fe), platinum (Pt), nickel (Ni), aluminum (Al) and the like, and if an alloy, a binary alloy of the metal materials mentioned above, Examples include ternary alloys, specifically, steel, stainless steel, copper alloy, titanium alloy, nickel alloy, and the like. If steel, for example, carbon steel, high alloy steel, low alloy steel, For example, stainless steel, for example, stainless general steel plate, stainless special steel plate, etc., and stainless steel general steel plate, for example, SUS201, SUS202, SUS301 to SU. 305, SUS309, SUS315, SUS321, SUS329, SUS347, SUS403, SUS405, SUS410, SUS420, SUS429, SUS430, SUS430LX, SUS434, SUS436, SUS440, SUS444, SUS445, SUS630, SUS636, SUS636, Specific examples of the steel plate include SUS316, SUS316Ti, SUS316LN, SUS316J1, SUS316J1L, SUS317, SUS317L, SUS317LN, SUS317J1, SUS317J2, SUS444, and SUS445. Examples of copper alloys include brass, red brass, silver, bronze, aluminum bronze, white bronze, red bronze, and constantan. Examples of aluminum alloys include 1000 series to 7000 series (JIS). In the case of a titanium alloy, for example, 6-4 titanium, α titanium, β titanium, α + β titanium, etc. may be mentioned, and in the case of a nickel alloy, for example, Hastelloy (registered trademark) ), Monel (registered trademark), Inconel (registered trademark), nichrome and the like, but the material constituting the metal substrate 2 is not limited to these.

  The conductive diamond-like carbon film 4 is preferably thin when viewed as a conductive layer, but is preferably thick when viewed as a protective layer. Therefore, the conductive diamond-like carbon film 4 has an optimum film thickness, and the film thickness is preferably 50 nm or more and 1000 nm or less, more preferably 100 nm or more and 600 nm or less, and 200 nm or more and 300 nm or less. Most preferably. When the thickness is less than 100 nm, the coverage performance for covering the metal substrate is deteriorated and the corrosion resistance is deteriorated. When the thickness exceeds 600 nm, the transparent electrode 6 is easily cracked, and the surface resistance value and the internal resistance are also increased. is there.

  Alternatively, at least a part of the surface of the conductive diamond-like carbon film 4 may have a porous shape, and at least a part of the conductive diamond-like carbon film 4 may have a porous shape. At this time, the thickness of the conductive diamond-like carbon film 4 is preferably 500 nm or more and 20000 nm or less, and more preferably 1000 nm or more and 5000 nm or less. Further, the thickness of the porous layer formed on the surface layer of the conductive diamond-like carbon film 4 is preferably 500 nm or more and 4000 nm or less, and more preferably 1000 nm or more and 2000 nm or less. The shape and thickness are not limited to those mentioned above.

  The catalyst layer 3 may be basically any material as long as it has a structure having a catalytic action for a reduction reaction. Specific examples include a platinum layer and a conductive carbon layer. .

The material constituting the catalyst layer 3 may be basically any material as long as it has conductivity, but it is preferable to use an electrochemically stable material, specifically Platinum, gold, carbon, ruthenium, rhodium, palladium, osmium, iridium, conductive polymer, and the like. Among the materials listed above, carbon may be basically any material as long as it is a substance composed of simple carbon, and preferably includes conductive carbon particles. Specific examples of the conductive carbon particles include carbon black. Among them, those having a large specific surface area are preferable. Carbon black having high electrical conductivity is suitable. Also, carbon black that is easy to form a structure is suitable. The average particle size of the primary particle size of carbon black is preferably 3 nm or more and 40 nm or less, more preferably 3 nm or more and 24 nm or less, and most preferably 3 nm or more and 15 nm or less. Is preferred. Specific examples of the carbon black include ketjen black, furnace black, lamp black, channel black, acetylene black, and thermal black. Among these, ketjen black that is inexpensive and has a large specific surface area is preferable. In addition to the carbons listed above, carbon is linear or rod-like carbon, sheet-like carbon crystal, graphite, graphite ribbon, graphite, amorphous carbon (glassy carbon), diamond-like carbon, carbon fiber, activated carbon, Petroleum coke, fullerenes such as C ₆₀ and C ₇₀ , single-walled or multi-walled carbon nanotubes may be used, but carbon is not limited to these. Examples of the conductive polymer include polyaniline, polypyrrole, polythiophene, and derivatives thereof. However, the conductive polymer is not limited to these, and the material constituting the catalyst layer 3 is also described above. The catalyst layer 3 can also be configured by appropriately combining the materials listed above.

  The catalyst layer 3 may have any shape as long as it has a configuration provided in contact with the conductive diamond-like carbon film 4, but is typically provided by being laminated on the conductive diamond-like carbon film 4. The catalyst layer 3 may be composed of a plurality of catalyst layers, and may be configured by stacking catalyst layers having the same configuration or may be configured by stacking catalyst layers having different configurations. The thickness of the catalyst layer 3 is preferably 5 μm or more and 200 μm or less, more preferably 5 μm or more and 100 μm or less, and most preferably 10 μm or more and 100 μm or less. This is because when the thickness of the catalyst layer 3 is 5 μm or less, the ability to reduce the redox species in the electrolytic solution constituting the electrolyte layer 8 is lowered, and the photoelectric conversion efficiency is lowered. Further, when the thickness of the catalyst layer 3 is 200 μm or more, the potential movement inside the counter electrode 1 cannot be performed smoothly.

  Further, the catalyst layer 3 is preferably formed so that a fine structure is formed on the surface of the catalyst layer 3 and an actual surface area is increased in order to improve the catalytic action for the reduction reaction. The actual surface area includes mesopores of carbon particles when the catalyst layer 3 is made of conductive carbon. The actual surface area of the catalyst layer 3 is preferably 10 times or more, and particularly preferably 100 times or more the area (projected area) of the outer surface of the catalyst layer 3.

[Method for producing counter electrode for dye-sensitized photoelectric conversion element]
Next, the manufacturing method of the counter electrode 1 for dye-sensitized photoelectric conversion elements according to the first embodiment will be described.
First, a metal plate that is the metal substrate 2 is prepared.
Next, a conductive diamond-like carbon film 4 is formed on the entire main surface of the metal substrate 2. Although there is no restriction | limiting in particular in the formation method of this electroconductive diamond-like carbon film 4, Specifically, physical vapor deposition methods, such as chemical vapor deposition methods (CVD), such as plasma CVD method, and ion plating method, are mentioned, for example. (PVD), ionized vapor deposition, sputtering, or the like. At this time, the conductive diamond-like carbon film 4 is formed by doping a group V element such as nitrogen. Further, when the conductive diamond-like carbon film 4 is formed, the non-conductive layer of the metal substrate 2, for example, a resistance layer component such as an oxide film, is sufficiently etched and plasma treatment using an inert gas is sufficient. It is preferable to remove. Also, the shorter the time from the removal treatment to the formation treatment of the conductive diamond-like carbon film 4 is, the better. The movement space during the formation process is also in an environment where it is difficult to form a nonconductive layer such as a nitrogen atmosphere or a vacuum atmosphere. Is desirable.

  Next, the catalyst layer 3 is formed on the surface of the conductive diamond-like carbon film 4. Although the formation method of the catalyst layer 3 is not specifically limited, For example, when the catalyst layer 3 is a conductive carbon layer, a wet film forming method or the like is used. Further, when the catalyst layer 3 is a metal layer, for example, a sputtering method, a chemical vapor deposition method, an ionization deposition method, or the like is used. Further, when the catalyst layer 3 is, for example, a conductive polymer layer, a wet film forming method or the like is used. In the wet film forming method, a method of preparing a paste-like dispersion and applying or printing this dispersion on at least a part of the surface of the conductive diamond-like carbon film 4 is preferable.

  The formation method when the catalyst layer 3 is a conductive carbon layer is specifically prepared by preparing a paste-like dispersion liquid in which carbon, an organic binder, and an inorganic binder are uniformly dispersed in a solvent and printing paste And Next, the above printing paste is printed as a paint on the surface of the conductive diamond-like carbon film 4 to form a coating film on at least a part of the surface of the conductive diamond-like carbon film 4. A metal substrate 2 having a carbon coating film on the carbon film 4 was obtained. Next, the obtained carbon coating film is baked. This is because, when the carbon coating film is baked, the carbons are electrically and mechanically connected to each other to improve the electrical conductivity and mechanical strength, and the binding property to the conductive diamond-like carbon film 4 is increased. This is because a high-performance catalyst layer 3 can be obtained. Moreover, the organic binder in the said carbon coating film lose | disappears by baking, a pore is formed in the catalyst layer 3 obtained, and the real surface area of the catalyst layer 3 becomes large. In this way, the catalyst layer 3 is formed on the conductive diamond-like carbon film 4, and the desired counter electrode 1 for the dye-sensitized photoelectric conversion element is obtained. When the catalyst layer 3 is composed of a plurality of layers, the catalyst layer 3 may be obtained by further forming and baking a carbon coating film on the carbon coating film formed on the metal substrate 2, The catalyst layer 3 may be obtained by firing a carbon coating film formed on the metal substrate 2 and further forming and firing a carbon coating film on the obtained sintered body.

The carbon, inorganic binder, and organic binder blended in the printing paste can be appropriately selected from conventionally known materials. Preferably, carbon black is used as carbon, titanium oxide (TiO ₂ ) is used as the inorganic binder, and organic binder is used. Ethyl cellulose is selected as the binder.

<Example 1>
The counter electrode 1 was manufactured as follows.
First, a SUS430 steel plate having a thickness of 1 mm was prepared as the metal substrate 2.
Next, the entire surface of one main surface of the SUS430 steel plate is etched to remove the non-conductive layer. After removing the non-conductive layer, the conductive diamond-like carbon film 4 is formed on the entire main surface of the SUS430 steel plate that is the metal substrate 2 by plasma CVD to obtain the metal substrate 2 having the conductive diamond-like carbon film 4. It was. The thickness of the obtained conductive diamond-like carbon film 4 was about 500 nm.

  Next, ketjen black and graphite as carbon, titanium oxide as an inorganic binder, and ethyl cellulose as an organic binder were added to terpineol as a solvent, and the mixture was stirred and dispersed to prepare a paste-like dispersion to obtain a printing paste.

  Next, at least a part of the conductive diamond-like carbon film 4 formed on the SUS430 steel plate as the metal substrate 2 is printed with a printing machine using the printing paste prepared in the previous step as a coating material. A carbon coating film was obtained on the carbon film 4. Then, in order to evaporate the solution in the obtained coating film, it is heated and dried on a hot plate at 100 ° C. to obtain a SUS430 steel plate which is a metal substrate 2 having a conductive carbon layer on the conductive diamond-like carbon film 4. It was.

Next, the obtained conductive carbon layer was fired. The temperature was raised to 400 ° C. in 1 hour and 30 minutes, and the mixture was kept at 400 ° C. for 30 minutes and calcined. By this step, ethyl cellulose is completely decomposed and lost.
Next, a carbon coating film is further formed and fired on the fired conductive carbon layer in the same manner. This process is performed twice to obtain a catalyst layer 3 which is a three-fired carbon layer. Thus, a SUS430 steel plate, which is the metal substrate 2 having the catalyst layer 3 on the conductive diamond-like carbon film 4, was obtained. The resulting catalyst layer 3 had a thickness of about 35 μm.
Thus, the intended counter electrode 1 was manufactured.

<Example 2>
A counter electrode 1 was produced in the same manner as in Example 1 except that the catalyst layer 3 was made one layer. The resulting catalyst layer 3 had a thickness of about 12 μm.

<Example 3>
A counter electrode 1 was produced in the same manner as in Example 1 except that the catalyst layer 3 was composed of two layers. The obtained catalyst layer 3 had a thickness of about 23 μm.

<Comparative Example 1>
A titanium plate having a thickness of 1 mm was prepared as the metal substrate 2.
Next, the entire main surface of the titanium plate is etched to remove the non-conductive layer. Next, a printing paste was printed as a paint on at least a part of the metal substrate 2 with a printing machine to obtain a coating film on the metal substrate 2. Thereafter, in order to evaporate the solution in the obtained coating film, it was heated on a hot plate at about 100 ° C. and dried to obtain a metal substrate 2 having a carbon layer. Other than that, the target counter electrode 1 was obtained in the same manner as in Example 1. The same printing paste as in Example 1 was used. The obtained catalyst layer 3 had a thickness of 35 μm.

<Comparative example 2>
A counter electrode 1 was produced in the same manner as in Example 1 except that the catalyst layer 3 was not formed on the conductive diamond-like carbon film 4.

  As described above, according to the first embodiment, since the counter electrode 1 for the dye-sensitized photoelectric conversion element is constituted by the conductive diamond-like carbon film 4 and the carbon catalyst layer 3, a large-scale facility for manufacturing is provided. Therefore, since the expensive platinum material is not used, the counter electrode 1 for the dye-sensitized photoelectric conversion element can be manufactured at low cost.

<2. Second Embodiment>
[Dye-sensitized photoelectric conversion element]
Next, the dye-sensitized photoelectric conversion element 10 according to the second embodiment will be described.
In the second embodiment, the counter electrode 1 of the dye-sensitized photoelectric conversion element according to the first embodiment is used as the counter electrode 1 of the dye-sensitized photoelectric conversion element 10.

FIG. 2 is a cross-sectional view of the main part showing the basic configuration of the dye-sensitized photoelectric conversion element 10 according to the second embodiment.
As shown in FIG. 2, the dye-sensitized photoelectric conversion element 10 is provided with a transparent electrode 6 on one main surface of a transparent substrate 5. A porous electrode 7 is provided on at least a part of the transparent electrode 6. One or more kinds of photosensitizing dyes (not shown) are bonded to the porous electrode 7. As the counter electrode 1, the counter electrode 1 according to the first embodiment is used. An electrolyte layer 8 made of an electrolytic solution is filled between the porous electrode 7 on the transparent substrate 5 and the counter electrode 1. The catalyst layer 3 and the porous electrode 7 are opposed to each other with the electrolyte layer 8 interposed therebetween. Between the transparent substrate 5 and the metal substrate 2, a sealing body 9 is provided in contact with the conductive diamond-like carbon film 4 formed on the metal substrate 2 in a form that does not leak the electrolyte of the electrolyte layer 8. Yes.

As the porous electrode 7, a porous semiconductor layer in which semiconductor fine particles are sintered is typically used. The photosensitizing dye is adsorbed on the surface of the semiconductor fine particles. As a material for the semiconductor fine particles, an elemental semiconductor typified by silicon, a compound semiconductor, a semiconductor having a perovskite structure, or the like can be used. These semiconductors are preferably n-type semiconductors in which conduction band electrons become carriers under photoexcitation and generate an anode current. Specifically, for example, titanium oxide (TiO ₂ ), zinc oxide (ZnO), tungsten oxide (WO ₃ ), niobium oxide (Nb ₂ O ₅ ), strontium titanate (SrTiO ₃ ), tin oxide (SnO ₂ ). Such semiconductors are used. Among these semiconductors, it is preferable to use TiO ₂ , especially anatase TiO ₂ . However, the types of semiconductors are not limited to these, and two or more types of semiconductors can be mixed or combined as necessary. Further, the shape of the semiconductor fine particles may be any of a particulate shape, a tube shape, a rod shape, and the like.

  The particle size of the semiconductor fine particles is not particularly limited, but the average particle size of the primary particle size is preferably 1 nm to 200 nm, and particularly preferably 5 nm to 100 nm. It is also possible to improve the quantum yield by mixing particles having a size larger than that of the semiconductor fine particles and scattering incident light with these particles. In this case, the average size of the separately mixed particles is preferably 20 nm or more and 500 nm or less, but the separately mixed particles are not limited thereto.

  The porous electrode 7 preferably has a large actual surface area so that as many photosensitizing dyes as possible can be bonded. The actual surface area includes mesopores of semiconductor particles constituting the porous electrode 7. The actual surface area in a state where the porous electrode 7 is formed on the transparent electrode 6 is preferably 10 times or more with respect to the area (projected area) of the outer surface of the porous electrode 7, and 100 times The above is particularly preferable. This ratio has no particular upper limit, but is usually about 1000 times.

  The shape of the porous electrode 7 may be basically any shape. In particular, when the sealing body 9 is provided between the transparent substrate 5 and the metal substrate 2, the sealing body 9 is formed on at least a part of a portion other than the outer edge portion on the transparent substrate 5 on which 9 is provided. In particular, in the case where the current collector wiring is provided on the transparent substrate 5, the shape of the porous electrode 7 is appropriately selected depending on the shape of the current collector wiring.

  The thickness of the porous electrode 7 is preferably 0.1 μm or more and 100 μm or less, more preferably 1 μm or more and 50 μm or less, and 3 μm or more and 30 μm or less. Most preferred. This is because, when the thickness of the porous electrode 7 is 0.1 μm or less, the number of semiconductor fine particles contained per unit projected area is small, and thus the amount of photosensitizing dye that can be held in the unit projected area. This is because there is little light and it is impossible to absorb light efficiently. Further, when the thickness of the porous electrode 7 exceeds 100 μm, the distance that the electrons transferred from the photosensitizing dye to the porous electrode 7 diffuse until reaching the transparent electrode 6 increases. This is because the loss of electrons due to the charge recombination increases.

  The transparent substrate 5 is not particularly limited as long as it has a material and shape that easily transmit light, and various materials can be used, and in particular, a substrate material having a high visible light transmittance is used. Is preferred. In addition, a material having a high blocking performance for blocking moisture and gas from entering the dye-sensitized photoelectric conversion element 10 from the outside and having excellent solvent resistance and weather resistance is preferable. Specific examples of the material for the transparent substrate 5 include transparent inorganic materials, transparent plastics, and the like. Examples of the transparent substrate 5 include quartz glass, borosilicate glass, phosphate glass, and soda glass. For transparent plastics, for example, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, acetyl cellulose, tetraacetyl cellulose, polyphenylene sulfide, polycarbonate, polyethylene, polypropylene, polyvinylidene fluoride, brominated phenoxy, amides, poly Polyimides such as etherimide, polystyrenes, polyarylates, polysulfones such as polyestersulfone, polyolefins and the like can be mentioned. Further, the thickness of the transparent substrate 5 is not particularly limited, and can be appropriately selected in consideration of the light transmittance and the performance of blocking the inside and outside of the photoelectric conversion element.

  The transparent electrode 6 provided on the transparent substrate 5 is a conductive thin film, and the smaller the sheet resistance, the better. Specifically, it is preferably 1Ω / □ or more and 500Ω / □ or less, and more preferably 1Ω / □ or more and 100Ω / □ or less. This is because if it exceeds 100Ω / □, the internal resistance of the transparent electrode 6 is remarkably increased. Further, the thickness of the transparent electrode 6 which is a thin film is preferably 100 nm or more and 500 nm. This is because when the thickness is less than 100 nm, the surface resistance value and the internal resistance increase, and when it exceeds 500 nm, the transparent electrode 6 is easily cracked. Moreover, a well-known material can be used as a material which comprises the transparent electrode 6, and it selects as needed. Typically, a metal oxide, for example, indium-tin composite oxide (ITO), fluorine-doped tin oxide (IV) SnO2 (FTO), tin oxide (IV) SnO2, zinc oxide (II) Examples thereof include ZnO and indium-zinc composite oxide (IZO). However, the material constituting the transparent electrode 6 is not limited to these, and may be a thin film of metal or mineral. For example, platinum, gold, silver, chromium, copper, tungsten, Aluminum etc. are mentioned. Moreover, it can also be set as the transparent electrode 6 combining two or more types mentioned above.

  The photosensitizing dye to be bonded to the porous electrode 7 is not particularly limited as long as it exhibits a sensitizing action, but those having an acid functional group adsorbed on the surface of the porous electrode 7 are preferable. In general, the photosensitizing dye preferably has a carboxy group, a phosphoric acid group, and the like, and among them, those having a carboxy group are particularly preferable. Specific examples of the photosensitizing dye include xanthene dyes, cyanine dyes, basic dyes, porphyrin compounds, and the like. Examples of xanthene dyes include rhodamine B, rose bengal, eosin, and erythrosine. Examples of cyanine dyes include merocyanine, quinocyanine, and cryptocyanine. Examples of basic dyes include phenosafranine, fog blue, thiocin, and methylene blue, and porphyrin compounds. Then, for example, chlorophyll, zinc porphyrin, magnesium porphyrin and the like can be mentioned. Others applicable to the photosensitizing dye include, for example, azo dyes, phthalocyanine compounds, coumarin compounds, bipyridine complex compounds, anthraquinone dyes, polycyclic quinone dyes, and the like. Among these, the quantum yield is high, the ligand (ligand) includes a pyridine ring or an imidazolium ring, ruthenium (Ru), osmium (Os), iridium (Ir), platinum (Pt), cobalt (Co), A pigment of at least one metal complex selected from the group consisting of iron (Fe) and copper (Cu) is preferred. Further, among these, cis-bis (isothiocyanate) -N, N-bis (2,2′-dipyridyl-4,4′-dicarboxylic acid) -ruthenium (II) or tris (isothione) has a particularly wide absorption wavelength range. (Osocyanato) -ruthenium (II) -2,2 ': 6', 2 "-terpyridine-4,4 ', 4" -tricarboxylic acid is preferred as a dye molecule. However, it is not limited to these. Moreover, as a photosensitizing dye, typically one of these is used, but two or more kinds of photosensitizing dyes may be mixed and used. When two or more kinds of photosensitizing dyes are used in combination, the photosensitizing dye is preferably an inorganic complex dye having a property of causing MLCT (Metal to Ligand Charge Transfer) held in the porous electrode 7. And an organic molecular dye having the property of intramolecular CT (Charge Transfer) held in the porous electrode 7. In this case, the inorganic complex dye and the organic molecular dye are adsorbed on the porous electrode 7 in different conformations. The inorganic complex dye preferably has a carboxy group or a phosphono group as a functional group bonded to the porous electrode 7. The organic molecular dye preferably has a carboxy group or a phosphono group and a cyano group, an amino group, a thiol group, or a thione group as functional groups bonded to the porous electrode 7 on the same carbon. The inorganic complex dye is, for example, a polypyridine complex, and the organic molecular dye is, for example, an aromatic polycyclic conjugated molecule having an electron donating group and an electron accepting group and having intramolecular CT properties.

Examples of the electrolytic solution constituting the electrolyte layer 8 include a solution containing a redox system (redox pair). Specific examples of the redox system include a combination of iodine (I ₂ ) and a metal or organic iodide salt, a combination of bromine (Br ₂ ) and a metal or organic bromide salt, or the like. . The cations constituting the metal salt are, for example, lithium (Li ⁺ ), sodium (Na ⁺ ), potassium (K ⁺ ), cesium (Cs ⁺ ), magnesium (Mg ²⁺ ), calcium (Ca ²⁺ ) and the like. . Further, as the cation constituting the organic salt, quaternary ammonium ions such as tetraalkylammonium ions, pyridinium ions and imidazolium ions are suitable. These may be used alone or in combination of two or more. Can be used.

  In addition to the above, the electrolyte solution constituting the electrolyte layer 8 includes a metal complex such as a combination of ferrocyanate and ferricyanate, a combination of ferrocene and ferricinium ion, sodium polysulfide, alkylthiol, and the like. Sulfur compounds such as combinations with alkyl disulfides, viologen dyes, combinations of hydroquinone and quinone, and the like can also be used.

  If the sealing body 9 has a structure that prevents leakage of the electrolyte of the electrolyte layer 8 to the outside, drying of the electrolyte in the electrolyte layer 8, mixing of substances into the electrolyte layer 8, etc., basically. Any material may be used, and as the material of the sealing body 9, it is preferable to use a material having light resistance, insulation, moisture resistance, and the like. The sealing body 9 may be transparent or opaque, but the sealing body 9 is preferably capable of transmitting light having a wavelength of 340 nm or more, and transmits light having a wavelength of 380 nm to 900 nm. More preferably, the light can be transmitted, and most preferably, light having a wavelength of 400 nm to 800 nm can be transmitted. Specific examples of the material constituting the encapsulant 9 are epoxy resin, thermosetting isomeric resin, ultraviolet (UV) curable resin, heat welding resin, acrylic resin, polyisobutylene resin, EVA (ethylene vinyl acetate), ionomer. Resin, ceramic, various heat-sealing films, etc., which may be a mixture of inorganic filler, metal filler, carbon particles, etc. dispersed in the above-mentioned materials, Is not limited to those listed above, and the sealing body 9 can be configured by appropriately combining those listed above. The sealing body 9 is typically provided between the transparent substrate 5 and the metal substrate 2, but is not limited thereto, and the outer peripheral portions of the transparent substrate 5 and the metal substrate 2 are sealed with the sealing body 9. 9 may be sealed.

[Operation of dye-sensitized photoelectric conversion element]
Next, the operation of the dye-sensitized photoelectric conversion element 10 according to the second embodiment will be described.
When the light is incident, the dye-sensitized photoelectric conversion element 10 operates as a battery having the counter electrode 1 as a positive electrode and the transparent electrode 6 as a negative electrode. The principle is as follows. Here, it is assumed that FTO is used as the material of the transparent electrode 6, TiO ₂ is used as the material of the porous electrode 7, and a redox species of I ⁻ / I ₃ ⁻ is used as the redox pair. It is not limited to this configuration. Further, it is assumed that one kind of photosensitizing dye is bonded to the porous electrode 7.

When a photosensitizing dye that has passed through the transparent substrate 5 and the transparent electrode 6 and has entered the porous electrode 7 and has been bonded to the porous electrode 7 is absorbed, electrons in the photosensitizing dye are released from the ground state (HOMO). Excited to an excited state (LUMO). The electrons thus excited are drawn out to the conduction band of TiO ₂ constituting the porous electrode 7 through electrical coupling between the photosensitizing dye and the porous electrode 7, and pass through the porous electrode 7. It reaches the transparent electrode 6.

On the other hand, the photosensitizing dye that has lost the electrons receives electrons from the reducing agent in the electrolyte layer 8, for example, I by the following reaction, and oxidants such as I ₃ ⁻ (I ₂ and I ⁻ Conjugate).
2I ⁻ → I ₂ + 2e ^{−
_{I 2 + I - → I 3}} -

The oxidant thus generated reaches the catalyst layer 3 constituting the counter electrode 1 by diffusion, receives electrons from the catalyst layer 3 by the reverse reaction of the above reaction, and is reduced to the original reducing agent.
^{_{I 3 - → I 2 + I}} -
I ₂ + 2e ^- → 2I ^-

  The electrons sent from the transparent electrode 6 to the external circuit perform electrical work in the external circuit, and then return to the catalyst layer 3 through the metal substrate 2 and the conductive diamond-like carbon film 4 constituting the counter electrode 1. In this way, light energy is converted into electrical energy without leaving any change in the photosensitizing dye or the electrolyte layer 8.

[Method for producing dye-sensitized photoelectric conversion element]
Next, a method for manufacturing the dye-sensitized photoelectric conversion element 10 according to the second embodiment will be described.
First, a transparent plate is prepared as the transparent substrate 5. Next, the transparent electrode 6 is formed by forming a transparent conductive layer on one main surface of the transparent substrate 5 by sputtering or the like.

  On the transparent electrode 6, a current collecting wiring may be formed by vacuum-depositing metal in a desired pattern. The metal used is preferably aluminum (Al). Further, the current collector wiring protective layer is formed by oxidizing the surface of the current collector wiring by heat treatment, electrical treatment or chemical treatment. The current collector wiring can also be formed by welding, adhesion, fusion, coating, plating, sputtering, various CVD methods, and the like. Further, the current collecting wiring may be formed by printing a mixture of conductive particles and resin on the transparent electrode 6 by screen printing and then firing. The conductive particles are preferably metal particles.

  Next, the porous electrode 7 is formed on the surface on the transparent electrode 6. The method for forming the porous electrode 7 is not particularly limited, but in consideration of physical properties, convenience, manufacturing cost, etc., it is preferable to use a wet film forming method. In the wet film forming method, a paste-like dispersion liquid in which a powder or sol of semiconductor fine particles is uniformly dispersed in a solvent such as water is prepared, and this dispersion liquid is applied or printed on the transparent electrode 6 of the transparent substrate 5. Is preferred. There is no restriction | limiting in particular in the application method or printing method of a dispersion liquid, A well-known method can be used. Specifically, as a coating method, for example, a dipping method, a spray method, a wire bar method, a spin coating method, a roller coating method, a blade coating method, a gravure coating method, or the like can be used. Moreover, as a printing method, a relief printing method, an offset printing method, a gravure printing method, an intaglio printing method, a rubber plate printing method, a screen printing method, etc. can be used.

When anatase-type TiO ₂ is used as the material for the semiconductor fine particles, this anatase-type TiO ₂ may be a commercially available product in the form of powder, sol, or slurry, or is known such as hydrolyzing titanium oxide alkoxide. A material having a predetermined particle diameter may be formed by a method. When using a commercially available powder, it is preferable to eliminate secondary agglomeration of the particles, and it is preferable to pulverize the particles using a mortar, ball mill or the like when preparing the paste-like dispersion. At this time, acetylacetone, hydrochloric acid, nitric acid, a surfactant, a chelating agent, and the like can be added to the paste-like dispersion in order to prevent the particles from which secondary aggregation has been eliminated from aggregating again. In addition, in order to increase the viscosity of the paste-like dispersion, polymers such as polyethylene oxide and polyvinyl alcohol, or various thickeners such as a cellulose-based thickener can be added to the paste-like dispersion.

  The porous electrode 7 is formed by coating or printing semiconductor fine particles on the transparent electrode 6, and then electrically connecting the semiconductor fine particles to improve the mechanical strength of the porous electrode 7, thereby improving adhesion with the transparent electrode 6. In order to improve, it is preferable to form by baking. There is no particular limitation on the range of the firing temperature, but if the temperature is raised too much, the electrical resistance of the transparent electrode 6 increases, and the transparent electrode 6 may melt. 40 ° C. or higher and 650 ° C. or lower is more preferable. Moreover, although there is no restriction | limiting in particular in baking time, Usually, it is about 10 minutes or more and 10 hours or less.

  After the porous electrode 7 is fired, for example, a dip treatment with a titanium tetrachloride aqueous solution or a titanium oxide ultrafine particle sol having a diameter of 10 nm or less is performed for the purpose of increasing the surface area of the semiconductor fine particles or increasing the necking between the semiconductor fine particles. May be. When a plastic substrate is used as the transparent substrate 5 that supports the transparent electrode 6, the porous electrode 7 is formed on the transparent electrode 6 using a paste-like dispersion containing a binder, and the transparent electrode 6 is heated by pressing. It is also possible to pressure-bond to.

  Next, the photosensitizing dye is bonded to the porous electrode 7 by immersing the transparent substrate 5 on which the porous electrode 7 is formed in a solution in which the photosensitizing dye is dissolved in a predetermined solvent.

  The method for adsorbing the photosensitizing dye to the porous electrode 7 is not particularly limited. For example, the photosensitizing dye may be an alcohol, nitrile, nitromethane, halogenated hydrocarbon, ether, dimethyl sulfoxide, amide, It is dissolved in a solvent such as N-methylpyrrolidone, 1,3-dimethylimidazolidinone, 3-methyloxazolidinone, esters, carbonates, ketones, hydrocarbons, water, and the porous electrode 7 is immersed in the solution. A solution containing a photosensitizing dye can be applied on the porous electrode 7. Further, deoxycholic acid or the like may be added for the purpose of reducing association between molecules of the photosensitizing dye. Moreover, a ultraviolet absorber can also be used together as needed. Further, after the photosensitizing dye is adsorbed on the porous electrode 7, the surface of the porous electrode 7 may be treated with amines for the purpose of promoting the removal of the excessively adsorbed photosensitizing dye. . Examples of amines include pyridine, 4-tert-butylpyridine, polyvinylpyridine, and the like. When these are liquid, they may be used as they are, or may be used after being dissolved in an organic solvent.

  Next, the counter electrode 1 was manufactured by the manufacturing method shown in the embodiment, and the counter electrode 1 in which the metal substrate 2 and the catalyst layer 3 were bound via the conductive diamond-like carbon film 4 was obtained. At this time, the catalyst layer 3 is not formed at the end portion on the conductive diamond-like carbon film 4, and the conductive diamond-like carbon film 4 is exposed at the end portion of the counter electrode 1.

  Next, the transparent substrate 5 and the metal substrate 2 are arranged so that the porous electrode 7 and the catalyst layer 3 have a predetermined interval. For example, the distance is preferably 1 μm or more and 100 μm or less, and more preferably 1 μm or more and 50 μm or less.

  Then, a sealing body 9 is formed between the transparent substrate 5 and the metal substrate 2 to create a space in which the electrolyte layer 8 is enclosed. First, the sealing body 9 is disposed in contact with the transparent substrate 5 or the transparent electrode 6 and the conductive diamond-like carbon film 4 exposed at the end of the counter electrode 1, and the sealing body 9 is cured.

  The curing method of the sealing body 9 may be basically any method. Specifically, for example, if the sealing body 9 is an ultraviolet curable resin, a method of curing by irradiating with ultraviolet rays. Moreover, for example, if the sealing body 9 is a thermosetting resin, a method of curing by applying heat or infrared rays may be used. In particular, if the sealing body 9 is a resin in which an ultraviolet (UV) curable resin and a thermosetting resin are combined, the conductive diamond-like carbon film 4 absorbs the ultraviolet light transmitted through the sealing body 9 when irradiated with ultraviolet light. Then, the sealing body 9 is heated by the generation of heat, and the binding and curing at the adhesion interface is promoted, so that the binding property between the conductive diamond-like carbon film 4 and the sealing body 9 is dramatically increased. To improve. The wavelength of the ultraviolet rays to be used is preferably 360 nm or more and 370 nm or less, but is not limited thereto. Further, in the case where the sealing body 9 is a heat welding resin, there is a method in which the sealing body 9 and the conductive diamond-like carbon film 4 are welded by irradiating a laser. The laser light that has passed through 9 is absorbed by the conductive diamond-like carbon film 4 and generates heat (at 200 ° C. or more), so that the conductive diamond-like carbon film 4 and the sealing body 9 are firmly bonded. The laser to be used is typically an infrared laser, and the wavelength thereof is preferably 700 nm or more and 1000 nm or less, and more preferably 800 nm or more and 900 nm or less. However, the laser to be used is limited to this. A visible light laser, an ultraviolet laser, or the like may be used instead. In addition, the method for curing the sealing body 9 can be appropriately combined with the methods listed above, but is not limited to these methods.

Next, an electrolyte solution is injected into a space formed by the transparent substrate 5, the metal substrate 2, and the sealing body 9, for example, from a liquid injection port (not shown) formed in the transparent substrate 5 in advance. 8 is formed. Thereafter, the liquid injection port is closed.
Thus, the target dye-sensitized photoelectric conversion element 10 is manufactured.

<Example 4>
The dye-sensitized photoelectric conversion element 10 was produced as follows.
First, as the transparent substrate 5 having the transparent electrode 6, a 1.1 mm thick FTO substrate (sheet resistance 10 Ω / □) made of Japanese plate glass for an amorphous solar cell was prepared.
Next, this FTO substrate was immersed in a 0.2 mol / l titanium tetrachloride solution at 70 ° C. for 40 minutes. Thereafter, it was washed with pure water, rinsed with ethanol and sufficiently dried.

Next, a TiO ₂ paste PST-24NRT (Catalyst Kasei Kogyo Co., Ltd.) was applied on the FTO layer of this FTO substrate by a screen method using a circular screen mask having a diameter of 5 mm to obtain a TiO ₂ coating film. .

Then overcoated with TiO ₂ paste PST-400C on the resulting TiO ₂ coating film to obtain a laminated TiO ₂ coating. Thereafter, the obtained laminated TiO ₂ coating film was held at 500 ° C. for 60 minutes and fired, and TiO ₂ fine particles were sintered on the FTO layer to obtain a TiO ₂ sintered body to be the porous electrode 7. The obtained TiO ₂ sintered body was circular with a diameter of 5 mm and had a thickness of 18 μm.

Next, for the purpose of removing impurities from the produced TiO ₂ sintered body and enhancing the activity, UV exposure was performed for 3 minutes with an excimer lamp.

Next, a dye soaking solution prepared by dissolving Z991 as a photosensitizing dye and DPA (1-decylphosphonic acid) as a coadsorbent in a tert-butyl alcohol / acetonitrile mixed solvent (volume ratio 1: 1) as a solvent. Prepared. The mixing ratio of Z991 and DPA was a molar ratio of Z991: DPA = 4: 1. Next, the TiO ₂ sintered body was immersed in the prepared dye soaking solution for 24 hours at room temperature to carry the dye. This TiO ₂ sintered body was washed with acetonitrile, and the solvent was evaporated and dried in the dark. Thus, a porous electrode 7 carrying a photosensitizing dye was obtained.

On the other hand, to 3-methoxypropionitrile (abbreviation MPN) as a solvent, 1.0 mol / l methoxypropioimidazolium iodide, 0.05 mol / l lithium iodide (LiI), 0.10 mol / l Iodine (I ₂ ) and 0.25 mol / l N-butylbenzmidazole (NBB) as an additive were dissolved to prepare an electrolytic solution.

  Next, the counter electrode 1 was manufactured by providing the catalyst layer 3 on at least a part of the conductive diamond-like carbon film 4 other than the outer edge by the method of Example 1. A sealing body 9 is joined to the outer edge portion of the counter electrode 1 where the conductive diamond-like carbon film 4 is exposed.

Next, the transparent substrate 5 and the metal substrate 2 are arranged so that the porous electrode 7 and the counter electrode 1 face each other with a predetermined interval. And between the transparent substrate 5 and the metal substrate 2, the sealing body 9 comprised with the ultraviolet curable resin and the thermosetting resin, one side of the sealing body 9 is the outer edge part of the transparent substrate 5, and the other is the counter electrode 1 The conductive diamond-like carbon film 4, which is the outer edge portion, is disposed in contact with the outer edge portion. Next, the sealing body 9 is hardened by irradiating with ultraviolet rays. When the sealing body 9 is cured, the transparent substrate 5 and the metal substrate 2 are firmly bound via the sealing body 9, and a space in which the electrolyte layer 8 is enclosed is formed. Next, for example, a liquid feed pump was used to inject into this space from a liquid injection port formed in advance on the transparent substrate 5, and the pressure inside the device was reduced to expel bubbles inside the device, thereby forming the electrolyte layer 8. Thereafter, the liquid injection port was sealed with a glass substrate using a sealing resin.
Thus, the intended dye-sensitized photoelectric conversion element 10 was manufactured.

<Comparative Example 3>
Except that the counter electrode 1 manufactured by the method of Comparative Example 1 was used and the sealing body 9 was provided in contact with the metal substrate 2 which is a titanium substrate constituting the counter electrode 1, the dye increase was performed in the same manner as in Example 4. The photoelectric conversion element 10 was manufactured.

  In order to measure the change in the characteristics of the dye-sensitized photoelectric conversion element 10 over time, a reliability acceleration test of the dye-sensitized photoelectric conversion element 10 of Example 4 and Comparative Example 3 was performed to compare the output characteristics. The reliability acceleration test was performed in the same manner as described above.

FIG. 3 shows a case where the dye-sensitized photoelectric conversion element 10 of Example 4 and Comparative Example 3 immediately before the start of the measurement in the reliability acceleration test is irradiated with simulated sunlight (AM1.5, 100 mW / cm ² ). It is a basic diagram which showed the measurement result of the IV output characteristic. Regarding the measurement, two samples, sample A and sample B, were prepared for the dye-sensitized photoelectric conversion element 10 of Example 4, and two samples C and C were also prepared for the dye-sensitized photoelectric conversion element 10 of Comparative Example 3. Samples were prepared, and the initial characteristics of samples A to D were measured and compared.

  From FIG. 3, when comparing the IV output characteristics of the dye-sensitized photoelectric conversion element 10 of Example 4 (Samples A and B) and Comparative Example 3 (Samples C and D), the dye-sensitized photoelectric conversion of Example 4 is compared. Sample A and Sample B, which are the elements 10, both showed a slightly high short-circuit current density, but samples A to D exhibited similar IV output characteristics.

  As a result, the dye-sensitized photoelectric conversion element 10 using the counter electrode 1 having a configuration in which the SUS430 steel plate and the catalyst layer 3 are bonded via the conductive diamond-like carbon film 4 is directly applied to the titanium plate. 3 has a high photoelectric conversion efficiency similar to that of the dye-sensitized photoelectric conversion element 10 using the counter electrode 1 having a configuration in which 3 is bound. This is because the conductive diamond-like carbon film 4 has the same conductivity as the metal substrate 2 such as a titanium plate, and the conductive diamond-like carbon film 4 and the SUS430 substrate and the catalyst layer 3 are well bound. Therefore, it is considered that the electrical connectivity is good and the electrical resistance at the interface between the metal substrate 2 and the catalyst layer 3 is small.

FIG. 4 shows simulated sunlight (AM1) in the dye-sensitized photoelectric conversion element 10 of Example 4 (Samples A and B) and Comparative Example 3 (Samples C and D) after 258 hours from the start of measurement in the reliability acceleration test. .5, 100 mW / cm ² ) is a schematic diagram showing measurement results of both IV output characteristics when irradiated. Regarding the measurement, the dye-sensitized photoelectric conversion elements 10 of Example 4 (Samples A and B) and Comparative Example 3 (Samples C and D) were respectively measured in the same manner as the measurement of the IV output characteristics immediately before the start of measurement. . The storage conditions of the dye-sensitized photoelectric conversion element 10 were a temperature of 85 ° C. and a humidity of 0%.

  From FIG. 4, when the IV output characteristics in the dye-sensitized photoelectric conversion element 10 of Example 4 (Samples A and B) and Comparative Example 3 (Samples C and D) are compared, Comparative Example 3 (Samples C and D) In the dye-sensitized photoelectric conversion element 10 of Example 4, although the short-circuit current density value increased compared with the IV output characteristic immediately before the start of measurement, the open-circuit voltage value significantly decreased, whereas Example 4 The dye-sensitized photoelectric conversion element 10 of (Samples A and B) had almost no characteristic change compared to the IV output characteristic immediately before the start of measurement. The fact that the change in the shape of the IV output characteristic of the dye-sensitized photoelectric conversion element 10 is small means that the change in the fill factor is small. Since the value of the photoelectric conversion efficiency is represented by the product of the open circuit voltage, the short-circuit current density, and the fill factor, if the change of the fill factor is small, the fluctuation of the photoelectric conversion efficiency is small and stable power generation can be performed.

  As a result, the IV output characteristics after 258 hours from the start of measurement of the dye-sensitized photoelectric conversion element 10 are obtained by using the counter electrode 1 having a configuration in which the catalyst layer 3 is directly fixed to the titanium plate which is the metal substrate 2. The dye-sensitized photoelectric conversion element 10 used varies greatly compared to immediately before the start of measurement, whereas the SUS steel plate and the catalyst layer 3 which are the metal substrate 2 are interposed via the conductive diamond-like carbon film 4. It was shown that the dye-sensitized photoelectric conversion element 10 using the counter electrode 1 having a bonded configuration hardly changes compared to immediately before the start of measurement. Thus, the dye-sensitized photoelectric conversion element 10 using the counter electrode 1 in which the metal substrate 2 and the catalyst layer 3 are bonded via the conductive diamond-like carbon film 4 has the catalyst layer 3 directly bonded. As compared with the dye-sensitized photoelectric conversion element 10 using the counter electrode 1, it was shown that stable power generation is possible with less fluctuation of the fill factor with time.

In order to further investigate the change over time in the output characteristics of the dye-sensitized photoelectric conversion element 10 of Example 4 and Comparative Example 3, attention was paid to the change over time of each characteristic of the dye-sensitized photoelectric conversion element 10. Therefore, the photoelectric conversion efficiency and the open circuit voltage of the dye-sensitized photoelectric conversion element 10 of Example 4 (Samples A and B) and Comparative Example 3 (Samples C and D) with respect to the elapsed time from the start of measurement in the reliability acceleration test described above. The change in the value of was measured. The storage conditions for the reliability acceleration test are the same as those for measuring the IV output characteristics, and the measurement conditions are the irradiation of simulated sunlight (AM1.5, 100 mW / cm ² ) continuously from the start of measurement to 258 hours. Measurements were made.

  Table 1 shows the measurement results of photoelectric conversion efficiency after 75 hours and 258 hours from the start of measurement in the dye-sensitized photoelectric conversion element 10 of Example 4 (Samples A and B) and Comparative Example 3 (Samples C and D). The photoelectric conversion efficiency measurement results immediately before the start of measurement are normalized as 100 (%).

  FIG. 5 shows the measurement results of photoelectric conversion efficiency with respect to the elapsed time in the dye-sensitized photoelectric conversion element 10 of Example 4 (Samples A and B) and Comparative Example 3 (Samples C and D). It is a basic diagram which each normalized and showed each measurement result as 100 (%).

  Table 2 shows the measurement results of the open circuit voltage after 75 hours and 258 hours from the start of measurement in the dye-sensitized photoelectric conversion element 10 of Example 4 (Samples A and B) and Comparative Example 3 (Samples C and D). The measurement results of the open circuit voltage immediately before the start of measurement are normalized as 100 (%).

  FIG. 6 shows the measurement results of the open-circuit voltage immediately before the start of the measurement with respect to the elapsed time in the dye-sensitized photoelectric conversion elements 10 of Example 4 (Samples A and B) and Comparative Example 3 (Samples C and D). It is the basic diagram which each normalized and showed the result as 100 (%).

  From Table 1 and FIG. 5, the photoelectric conversion efficiency in the dye-sensitized photoelectric conversion element 10 of Comparative Example 3 (Samples C and D) is lower than the initial production after 258 hours from the start of measurement. On the other hand, the photoelectric conversion efficiency in the dye-sensitized photoelectric conversion element 10 of Example 4 (Samples A and B) gradually increases after 100 hours from the production and then gradually decreases, but 258 hours from the start of measurement. It was shown that the photoelectric conversion efficiency was maintained at the same value as that immediately before the start of measurement even after elapse.

  From Table 2 and FIG. 6, the open-circuit voltage in the dye-sensitized photoelectric conversion element 10 of Comparative Example 3 (Samples C and D) is significantly lower than that at the beginning of production after 100 hours from the production. The open-circuit voltage in the dye-sensitized photoelectric conversion element 10 of Example 4 (Samples A and B) does not show a significant decrease, and always maintains the same value as immediately before the start of measurement until 258 hours have elapsed from the start of measurement. It was shown that

  Based on these results, the dye-sensitized photoelectric conversion element 10 using the counter electrode 1 having the configuration in which the metal substrate 2 and the catalyst layer 3 are bound via the conductive diamond-like carbon film 4 is formed on the metal substrate 2. Compared with the dye-sensitized photoelectric conversion element 10 using the counter electrode 1 having a structure in which the catalyst layer 3 is directly bonded to the electrode, the photoelectric conversion element has high photoelectric conversion efficiency even after storage for 258 hours from the start of measurement, and has an open circuit voltage. In addition, there was no significant drop in value due to changes over time, and it was shown that the same value as that immediately before the start of measurement was maintained.

  This is because the bond between the catalyst layer 3 and the conductive diamond-like carbon film 4 is stable to the electrolytic solution and heat, and the influence of the electrolytic solution on the binding interface is small. In particular, when the catalyst layer 3 is composed of a conductive carbon layer, since the carbon (C), which is the same element, becomes a bond, the bonding force is particularly high, the adhesion between the two is increased, and the catalyst is directly applied to the metal substrate 2. It is considered that the conductivity at the binding interface is improved as compared with the case where the layer 3 is formed. Further, since the binding between the catalyst layer 3 and the conductive diamond-like carbon film 4 is stable to the electrolytic solution and heat, the influence of the electrolytic solution on the binding interface is small. This is because the conductive diamond-like carbon film 4 also serves as a protective layer that does not allow the electrolyte to permeate, so that the electrolyte affects the binding interface between the conductive diamond-like carbon film 4 and the metal substrate 2. It is thought that this is because there is almost no.

  As described above, when the counter electrode 1 of the dye-sensitized photoelectric conversion element 10 is configured such that the metal substrate 2 and the catalyst layer 3 are bonded via the conductive diamond-like carbon film 4, the open circuit voltage of the initial stage of the measurement is reduced. There is no decline. From this, the characteristic drop of the open circuit voltage at the initial stage of the measurement observed in the dye-sensitized photoelectric conversion element 10 using the counter electrode 1 having the conventional metal substrate 2 is caused by the lapse of time in the counter electrode 1 having the conventional metal substrate 2. It was shown that it was due to the change taking place. Further, when the counter electrode 1 of the dye-sensitized photoelectric conversion element 10 is configured such that the metal substrate 2 and the catalyst layer 3 are bonded via the conductive diamond-like carbon film 4, the change with time of the counter electrode 1 is effectively performed. It can be suppressed, and it has been shown that the drop of the open circuit voltage in the initial driving stage can be effectively prevented. Furthermore, it has been shown that a decrease in photoelectric conversion efficiency with time can be effectively suppressed. As a result, the dye-sensitized photoelectric conversion element 10 can be physically and chemically more stable simply by making the counter electrode 1 of the dye-sensitized photoelectric conversion element 10 have the above-described configuration having the conductive diamond-like carbon film 4. It has been shown that the dye-sensitized photoelectric conversion element 10 having a very high reliability can be obtained.

  In addition, since the metal substrate 2 is covered with the conductive diamond-like carbon film 4, the conductive diamond-like carbon film 4 serves as a protective layer and the metal substrate 2 does not contact the electrolyte layer 8. As a result, the material constituting the metal substrate 2 and the electrolytic solution in the electrolyte layer 8 do not react and elute into the electrolytic solution, and the reactivity between the conductive diamond-like carbon film 4 and the electrolytic solution is small. Therefore, the conductive diamond-like carbon does not elute in the electrolytic solution.

  Further, since the sealing body 9 provided between the transparent substrate 5 and the metal substrate 2 is provided in close contact with the conductive diamond-like carbon film 4, the sealing body 9 is provided in contact with the metal substrate 2. Compared with, the binding property between the sealing body 9 and the metal substrate 2 is improved. In particular, when the sealing body 9 is an organic material, the organic material is bonded to each other, so that the binding property between the sealing body 9 and the metal substrate 2 is dramatically improved. This improvement in binding property can dramatically improve the water resistance to the electrolyte layer 8 when the dye-sensitized photoelectric conversion element 10 is operated in an environment where the outside is wet. Modification of the electrolyte solution can be suppressed.

  For these reasons, the dye-sensitized photoelectric conversion element 10 using the counter electrode 1 having a configuration in which the metal substrate 2 and the catalyst layer 3 are bound via the conductive diamond-like carbon film 4 is separated from the metal substrate 2. The substance does not elute into the electrolyte layer 8 and has high resistance to water from the outside. Therefore, the deterioration of the counter electrode 1 with time as described above is suppressed, and deterioration with time due to the modification of the electrolyte in the electrolyte layer 8 is prevented. Can also be suppressed.

  Next, in the case where the counter electrode 1 of the dye-sensitized photoelectric conversion element 10 is configured such that the metal substrate 2 and the catalyst layer 3 are bound via the conductive diamond-like carbon film 4, the conductive diamond-like carbon is used. The influence of the membrane 4 on the catalyst performance of the counter electrode 1 was examined. Specifically, the thickness of the catalyst layer 3 provided on the conductive diamond-like carbon film 4 in the counter electrode 1 of the dye-sensitized photoelectric conversion element 10 was changed, and various characteristics were measured for each element.

<Example 5>
A dye-sensitized photoelectric conversion element 10 was produced in the same manner as in Example 4 except that the counter electrode 1 produced by the method of Example 2 was used.

<Example 6>
A dye-sensitized photoelectric conversion element 10 was produced in the same manner as in Example 4 except that the counter electrode 1 produced by the method of Example 3 was used.

<Comparative example 4>
A dye-sensitized photoelectric conversion element 10 was manufactured in the same manner as in Example 4 except that the counter electrode 1 manufactured by the method of Comparative Example 2 was used.

Table 3 shows the case where the dye-sensitized photoelectric conversion element 10 of Example 4, Example 5, Example 6 and Comparative Example 4 immediately after production was irradiated with artificial sunlight (AM1.5, 100 mW / cm ² ). Each open circuit voltage V _OC (V), short circuit current density J _SC (mA / cm ² ), fill factor FF (%), conversion efficiency Eff. (%) And DC resistance R _S (Ω) measurement results are shown.

FIG. 7 shows a case in which artificial sunlight (AM1.5, 100 mW / cm ² ) is irradiated to the dye-sensitized photoelectric conversion element 10 of Example 4, Example 5, Example 6, and Comparative Example 4 immediately after the production. It is a basic diagram which showed the measurement result of each IV output characteristic. The dye-sensitized photoelectric conversion element 10 of Example 4 was newly prepared separately from the samples A to D.

  As shown in Table 3 and FIG. 7, the thickness of the catalyst layer 3 is 0, that is, the dye-sensitized photoelectric conversion element 10 using the counter electrode 1 in which only the conductive diamond-like carbon film 4 is provided on the metal substrate 2. It was shown that power generation by photoelectric conversion is possible. This indicates that the conductive diamond-like carbon itself has a reduction catalyst function.

  However, in the dye-sensitized photoelectric conversion element 10 of Comparative Example 4 using the counter electrode 1 having this configuration, although the open circuit voltage and the short-circuit current density show good values, the fill factor value is extremely low. For this reason, the photoelectric conversion efficiency was significantly lower than that of the dye-sensitized photoelectric conversion element 10 having another configuration. This indicates that the reduction catalyst function is remarkably insufficient only with the conductive diamond-like carbon film 4. One of the factors is that the surface of the conductive diamond-like carbon film 4 on the side of the electrolyte layer 8 is smooth, so that the surface area in contact with the electrolytic solution in the electrolyte layer 8 of the conductive diamond-like carbon film 4 is small. It is conceivable that the catalytic action is not sufficiently performed.

  Thus, even if the counter electrode 1 configured by providing only the conductive diamond-like carbon film 4 on the metal substrate 2 is applied to the dye-sensitized photoelectric conversion element 10, the reduction catalyst function is remarkably insufficient. This indicates that electrons generated in the porous electrode 7 cannot be effectively extracted outside.

  On the other hand, the dye-sensitized photoelectric conversion element 10 using the counter electrode 1 having a configuration in which the metal substrate 2 and the catalyst layer 3 are bonded via the conductive diamond-like carbon film 4 has a photoelectric conversion efficiency, an open-circuit voltage, Both the short-circuit current density and the fill factor showed good values. In particular, the catalyst layer 3 has a three-layer structure in the conventional dye-sensitized photoelectric conversion element 10 to obtain good photoelectric conversion efficiency, but the counter electrode 1 is made of metal through the conductive diamond-like carbon film 4. When the substrate 2 and the catalyst layer 3 are bonded, even if the catalyst layer 3 has a single layer structure, the photoelectric conversion efficiency value is equivalent to that of the conventional dye-sensitized photoelectric conversion element 10, and the catalyst layer When 3 has a two-layer structure, it has been clarified that a value larger than the photoelectric conversion efficiency value of the conventional dye-sensitized photoelectric conversion element 10 having a three-layer structure is exhibited. Thereby, the dye-sensitized photoelectric conversion element 10 using the counter electrode 1 having a configuration in which the metal substrate 2 and the catalyst layer 3 are bonded via the conductive diamond-like carbon film 4 has a good photoelectric conversion efficiency. Since the catalyst layer 3 is obtained in two layers, the catalyst layer 3 can be formed thinner than before, and the entire dye-sensitized photoelectric conversion element 10 can be formed thinner. However, the thickness of the catalyst layer 3 is not preferable if it is too thin or too thick, and an optimum thickness exists. The thickness is preferably 10 μm or more and 40 μm or less, more preferably 15 μm or more and 30 μm or less, and most preferably 20 μm or more and 25 μm or less.

  Thus, even if the counter electrode 1 formed by forming only the conductive diamond-like carbon film 4 on the metal substrate 2 is applied to the dye-sensitized photoelectric conversion element 10, good photoelectric conversion efficiency cannot be obtained. When the counter electrode 1 formed by binding the metal substrate 2 and the catalyst layer 3 through the conductive diamond-like carbon film 4 is applied to the dye-sensitized photoelectric conversion element 10, the catalyst layer 3 can be made thinner than before. It became clear that the value of a photoelectric conversion efficiency was shown.

  Here, in order to improve the catalytic action of the conductive diamond-like carbon film 4, at least a part of the surface on the electrolyte layer 8 side of the conductive diamond-like carbon film 4 constituting the counter electrode 1 may be made porous. Thereby, the area which the electrolyte solution in the electrolyte layer 8 and the electroconductive diamond-like carbon film 4 contact can be increased, and a catalytic action can be improved. Specifically, the conductive diamond-like carbon film 4 having at least a part of the porous shape may be formed, for example, by making the entire surface of the conductive diamond-like carbon film 4 on the electrolyte layer 8 side porous or conductive diamond-like carbon film 4. A porous shape is formed only in a portion where the surface of the carbon film 4 on the electrolyte layer 8 side is in contact with the electrolytic solution, or a portion other than a portion bonded to the sealing body 9 on the surface of the conductive diamond-like carbon film 4 on the electrolyte layer 8 is porous. It can be made into a shape. In addition, since the conductive diamond-like carbon film 4 has a role as a protective layer for the metal substrate 2, it is preferable that only the surface layer portion of the conductive diamond-like carbon film 4 has a porous shape. At this time, the thickness of the conductive diamond-like carbon film 4 is preferably 500 nm or more and 20000 nm or less, and more preferably 1000 nm or more and 5000 nm or less. Further, the thickness of the porous layer formed on the surface layer of the conductive diamond-like carbon film 4 is preferably 500 nm or more and 4000 nm or less, and more preferably 1000 nm or more and 2000 nm or less. The shape and thickness are not limited to those mentioned above.

  The conductive diamond-like carbon film 4 having a porous shape at least in part can be manufactured by adjusting the gas pressure when the film is formed by the plasma CVD method. The conductive diamond-like carbon film 4 having a porous layer is formed by forming a conductive diamond-like carbon film 4 having a smooth surface by a plasma CVD method, and then adjusting the gas pressure to form the porous conductive diamond-like carbon film 4. Form a film. Moreover, after forming the conductive diamond-like carbon film 4 having a smooth surface, it can be formed into a porous body using a chemical or electrical method.

  As described above, according to the dye-sensitized photoelectric conversion element 10 according to the second embodiment, in addition to the same advantages as the counter electrode 1 for the dye-sensitized photoelectric conversion element according to the first embodiment, the counter electrode 1 Since the metal substrate 2 and the catalyst layer 3 are bonded via the conductive diamond-like carbon film 4, the change with time of the counter electrode 1 can be suppressed for a long time. Thereby, the fall of the open circuit voltage by using the dye-sensitized photoelectric conversion element 10 for a long time and the fall of photoelectric conversion efficiency can be suppressed. Further, by covering the entire surface of the metal substrate 2 in contact with the electrolyte on the side of the electrolyte layer 8 with the conductive diamond-like carbon film 4, the conductive diamond-like carbon film 4 serves as a protective layer and the metal substrate 2 does not contact the electrolyte. The metal substrate 2 can be made of a metal having low resistance to electrolyte. Further, since the sealing body 9 provided between the transparent substrate 5 and the metal substrate 2 is provided in contact with the conductive diamond-like carbon film 4, the sealing body 9 is sealed as compared with the case in which it is provided in contact with the metal substrate 2. The binding property between the stationary body 9 and the metal substrate 2 is dramatically improved. Thereby, the time-dependent deterioration of the dye-sensitized photoelectric conversion element 10 can be suppressed by suppressing the modification of the electrolyte in the electrolyte layer 8. As described above, according to the second embodiment, the metal substrate 2 can be made of a material having a low electrolytic solution resistance, has a high photoelectric conversion efficiency, and has a high performance with little performance deterioration even when used for a long time. A dye-sensitized photoelectric conversion element 10 can be obtained.

<3. Third Embodiment>
[Counter electrode for dye-sensitized photoelectric conversion element]
Next, a counter electrode for a dye-sensitized photoelectric conversion element according to a third embodiment will be described.
FIG. 8 is a cross-sectional view of an essential part showing a counter electrode 1 for a dye-sensitized photoelectric conversion element according to a third embodiment.
As shown in FIG. 8, the counter electrode 1 for dye-sensitized photoelectric conversion element (hereinafter referred to as counter electrode 1) is provided with a conductive film 11 so as to cover the entire main surface of the metal substrate 2. A conductive diamond-like carbon film 4 is further provided so as to cover the entire surface, and a catalyst layer 3 is provided on at least a part of the surface of the conductive diamond-like carbon film 4. The conductive diamond-like carbon film 4 is in close contact with the metal substrate 2 and the catalyst layer 3, and these constitute the counter electrode 1. Others are the same as those of the counter electrode 1 for the dye-sensitized photoelectric conversion element of the first embodiment.

  The conductive film 11 may basically be any conductive film provided on the metal substrate 2, but the thickness of the conductive film 11 is preferably 30 nm or more and 300 nm or less. 50 nm or more and 200 nm or less is more preferable, and 80 nm or more and 150 nm or less is most preferable. This is because the surface resistance value and the internal resistance increase when the thickness is less than 20 nm. Further, specifically, the sheet resistance of the conductive film 11 is preferably 5Ω / □ or less, and more preferably 1Ω / □ or less. This is because if it exceeds 10Ω / □, the internal resistance of the transparent conductive layer is remarkably increased.

The material constituting the conductive film 11 is preferably a simple metal, an alloy, a ternary amorphous material, a metal carbide, a metal nitride, a metal cyanide, a conductive polymer, or the like. Specifically, gold, platinum, Silver, copper, iron, tin, zinc, nickel, titanium-based material, tantalum (Ta) -based material, chromium (Cr) -based material, tungsten (W) -based material, molybdenum (Mo) -based material, niobium (Nb) -based material , Aluminum (Al) material, hafnium (Hf) material, zirconium (Zr) material, ruthenium (Ru) material, iridium (Ir) material, and the like. For example, Ti, TiN, TiC, TiCN, TiBN, TiAlN, TiSiN, TiAlON, etc. can be mentioned. For example, Ta, TaN, TaCN, TaC, TaO, TaON, TaCNO, TaAlN, TaSiN and the like can be mentioned. Specifically, in the case of a chromium-based material, for example, Cr, CrN, CrSiN, CrAlN and the like can be mentioned. If it is a tungsten-based material, specifically, for example, W, WN, WCN, WBN, WAlN, WSiN, WTi, etc. may be mentioned, and if it is a molybdenum-based material, specifically, For example, Mo, MoO, MoN, MoSiN, MoAlN, MoHfO, and the like can be mentioned. Specific examples of niobium-based materials include Nb, NbN, NbC, NbSiN, NbAlN, and the like. Specific examples of aluminum-based materials include Al and AlN, and hafnium-based materials. Then, specific examples include Hf, HfN, HfC, and the like. Specific examples of the zirconium-based material include Zr, ZrN, ZrSiN, ZrAlN, and the like. Specific examples of the ruthenium-based material include Ru, RuO, RuAlO, and RuAlN. Specific examples of the iridium-based material include Ir and IrO. In addition, specific examples of conductive polymers include polyaniline, polypyrrole, polythiophene and derivatives thereof, and other materials include indium-tin composite oxide (ITO) and fluorine. Tin oxide (IV) SnO ₂ (FTO), tin oxide (IV) SnO ₂ , zinc oxide (II) ZnO, indium-zinc composite A compound oxide (IZO) and the like can be mentioned, but the material constituting the conductive film 11 is not limited to these. In addition, the conductive film 11 can be configured by combining two or more types from those listed above, or can be configured by stacking two or more types.

  Although the material which comprises the metal substrate 2 can be suitably selected and used from what was mentioned above, the stainless steel special steel which has high electrolyte solution corrosion resistance is preferable among these. The stainless special steel is a stainless steel having a passive film on the surface. Specific examples thereof include SUS316, SUS316Ti, SUS316LN, SUS316J1, SUS316J1L, SUS317, SUS317L, SUS317LN, SUS317J1, and SUS317J2.

[Method for producing counter electrode for dye-sensitized photoelectric conversion element]
Next, the manufacturing method of the counter electrode 1 for dye-sensitized photoelectric conversion elements according to the third embodiment will be described.
First, a metal plate that is the metal substrate 2 is prepared.
Next, the conductive film 11 is formed on the entire main surface of the metal substrate 2. Although there is no restriction | limiting in particular in the formation method of this electroconductive film 11, Specifically, it forms by sputtering method, chemical vapor deposition method, ionization vapor deposition method, etc. In particular, when the conductive film 11 is formed by a sputtering method, an inert gas or the like that is removed as a pre-process for film formation by the sputtering method is used to remove the non-conductive layer as a pre-process for forming the conductive film 11. Since it can be performed simultaneously with the reverse sputtering used, the process can be simplified. Next, a conductive diamond-like carbon film 4 is formed on the entire surface of the conductive film 11. Others are the same as the manufacturing method of the counter electrode 1 for dye-sensitized photoelectric conversion elements according to the first embodiment.

<Example 7>
The counter electrode 1 was manufactured as follows.
First, a SUS304 steel plate having a thickness of 1 mm was prepared as the metal substrate 2.
Next, the entire main surface of one of the SUS304 steel plates was reverse-sputtered with an inert gas to remove the nonconductive layer. After removing the non-conductive layer, a Ti film as the conductive film 11 was formed on the entire surface of one main surface of the SUS304 steel plate by sputtering, and the metal substrate 2 having the conductive film 11 was obtained. The thickness of the formed Ti film was 60 nm. Next, a conductive diamond-like carbon film 4 is formed on the entire surface of the formed Ti film by plasma CVD, and a Ti film as the conductive film 11 and a conductive diamond-like carbon film 4 are sequentially laminated. A SUS304 steel plate as substrate 2 was obtained. The thickness of the obtained conductive diamond-like carbon film 4 was about 200 nm. Other than that, the counter electrode 1 was manufactured in the same manner as in Example 1.

<Example 8>
The counter electrode 1 was manufactured as follows.
First, a SUS316 steel plate having a thickness of 1 mm was prepared as the metal substrate 2.
Next, the entire surface of one main surface of the SUS316 steel plate was reverse-sputtered with an inert gas to remove the nonconductive layer. After removing the non-conductive layer, a Ti film as the conductive film 11 was formed on the entire surface of one main surface of the SUS316 steel sheet by sputtering, and the metal substrate 2 having the conductive film 11 was obtained. The thickness of the formed Ti film was 60 nm. Next, a conductive diamond-like carbon film 4 is formed on the entire surface of the formed Ti film by plasma CVD, and a Ti film as the conductive film 11 and a conductive diamond-like carbon film 4 are sequentially laminated. A SUS304 steel plate as substrate 2 was obtained. The thickness of the obtained conductive diamond-like carbon film 4 was about 200 nm. Other than that, the counter electrode 1 was manufactured in the same manner as in Example 1.

<Example 9>
The counter electrode 1 was manufactured as follows.
First, a SUS316 steel plate having a thickness of 1 mm was prepared as the metal substrate 2.
Next, the entire surface of one main surface of the SUS316 steel plate was reverse-sputtered with an inert gas to remove the nonconductive layer. After removing the non-conductive layer, a TiN film as the conductive film 11 was formed on the entire surface of one main surface of the SUS316 steel plate by sputtering, and the metal substrate 2 having the conductive film 11 was obtained. The thickness of the formed TiN film was 50 nm. Next, a conductive diamond-like carbon film 4 is formed on the entire surface of the formed TiN film by plasma CVD, and a TiN film as the conductive film 11 and a conductive diamond-like carbon film 4 are sequentially laminated. A SUS316 steel plate as substrate 2 was obtained. The thickness of the obtained conductive diamond-like carbon film 4 was about 500 nm. Other than that, the counter electrode 1 was manufactured in the same manner as in Example 1.

<Comparative Example 5>
A counter electrode 1 was produced in the same manner as in Comparative Example 1 except that the metal substrate 2 was a SUS316 steel plate.

<Comparative Example 6>
A counter electrode 1 was produced in the same manner as in Example 1 except that the metal substrate 2 was a SUS316 steel plate.

  According to the third embodiment, the counter electrode 1 for a dye-sensitized photoelectric conversion element having the same advantages as those of the first embodiment can be obtained.

<4. Fourth Embodiment>
[Dye-sensitized photoelectric conversion element]
Next, the dye-sensitized photoelectric conversion element 10 according to the fourth embodiment will be described.
FIG. 9 is a cross-sectional view of the main part showing the basic configuration of the dye-sensitized photoelectric conversion element 10 according to the fourth embodiment.
As shown in FIG. 9, in the fourth embodiment, the counter electrode 1 for the dye-sensitized photoelectric conversion element according to the third embodiment is used as the counter electrode 1 for the dye-sensitized photoelectric conversion element 10. Others are the same as those of the dye-sensitized photoelectric conversion element 10 according to the second embodiment.

[Operation of dye-sensitized photoelectric conversion element]
Next, the operation of the dye-sensitized photoelectric conversion element 10 according to the fourth embodiment will be described.
The operation of the dye-sensitized photoelectric conversion element 10 is the same as the operation of the dye-sensitized photoelectric conversion element 10 according to the second embodiment.

[Method for producing dye-sensitized photoelectric conversion element]
Next, a method for manufacturing the dye-sensitized photoelectric conversion element 10 according to the fourth embodiment will be described.
The manufacturing method of the dye-sensitized photoelectric conversion element 10 is the same as that of the second embodiment except that the counter electrode 1 of the dye-sensitized photoelectric conversion element is the counter electrode 1 according to the third embodiment. This is the same as the manufacturing method of the dye-sensitized photoelectric conversion element 10 according to the form.

<Example 10>
A dye-sensitized photoelectric conversion element 10 was manufactured in the same manner as in Example 4 except that the counter electrode 1 manufactured by the method of Example 7 was used.

<Example 11>
A dye-sensitized photoelectric conversion element 10 was manufactured in the same manner as in Example 4 except that the counter electrode 1 manufactured by the method of Example 8 was used.

<Example 12>
A dye-sensitized photoelectric conversion element 10 was manufactured in the same manner as in Example 4 except that the counter electrode 1 manufactured by the method of Example 9 was used.

<Comparative Example 7>
Except for using the counter electrode 1 manufactured by the method of Comparative Example 5 and providing the sealing body 9 in contact with the metal substrate 2 that is the SUS316 substrate constituting the counter electrode 1, the dye increase was performed in the same manner as in Example 4. The photoelectric conversion element 10 was manufactured.

<Comparative Example 8>
A dye-sensitized photoelectric conversion element 10 was manufactured in the same manner as in Example 4 except that the counter electrode 1 manufactured by the method of Comparative Example 6 was used.

Table 4 shows the respective open-circuit voltages when pseudo-sunlight (AM1.5, 100 mW / cm ² ) was irradiated to the dye-sensitized photoelectric conversion elements 10 of Example 10, Example 11 and Comparative Example 7 immediately after production. V _OC (V), short circuit current density J _SC (mA / cm ² ), fill factor FF (%), conversion efficiency Eff. (%) And DC resistance R _S (Ω) measurement results are shown.

FIG. 10 shows the respective I− when the dye-sensitized photoelectric conversion element 10 of Example 10, Example 11 and Comparative Example 7 immediately after production was irradiated with simulated sunlight (AM1.5, 100 mW / cm ² ). It is a basic diagram which showed the measurement result of V output characteristic.

  As shown in Table 4 and FIG. 10, it is clear that the dye-sensitized photoelectric conversion elements 10 of Examples 10 and 11 have a low series resistance compared to the dye-sensitized photoelectric conversion element 10 of Comparative Example 7. It became. This is because the conductive film 11 and the conductive diamond-like carbon film 4 are sequentially laminated between the metal substrate 2 and the catalyst layer 3 of the counter electrode 1 of the dye-sensitized photoelectric conversion elements 10 of Examples 10 and 11. This is probably because the electrical affinity at each contact interface increased and the contact resistance decreased. The decrease in DC resistance is particularly noticeable in Example 10 in which the conductive film 11 is made of a titanium-based material and the metal substrate 2 is made of a general stainless steel plate. This is because the electrical affinity at the interface between SUS304, which is a general steel plate of stainless steel, and Ti, which is a titanium-based material film provided on the surface thereof, is similarly stainless steel provided with Ti, which is a titanium-based material film. This is probably because the electrical affinity at the interface of SUS316, which is a special steel plate, is even greater.

  Further, it was revealed that the dye-sensitized photoelectric conversion elements 10 of Examples 10 and 11 have higher photoelectric conversion efficiency than the dye-sensitized photoelectric conversion element 10 of Comparative Example 7. As this factor, from the comparison of the series resistance values described above, the conductivity between the negative and positive electrodes of the dye-sensitized photoelectric conversion elements 10 of Examples 10 and 11 is higher than that of the dye-sensitized photoelectric conversion element 10 of Comparative Example 7, This is considered to be because there is little energy loss when taking out electrons outside.

  Thus, the counter electrode 1 is bonded to the metal substrate 2 and the conductive diamond-like carbon film 4 via the conductive film 11, and the catalyst layer 3 is further bonded to the conductive diamond-like carbon film 4. With the provided configuration, the catalyst performance of the counter electrode 1 can be dramatically improved. Moreover, the photoelectric conversion efficiency in the dye-sensitized photoelectric conversion element 10 can be remarkably improved by using the counter electrode 1 having the above configuration as the counter electrode of the dye-sensitized photoelectric conversion element 10.

  Next, in order to measure a change in characteristics of the dye-sensitized photoelectric conversion element 10 over time, a reliability acceleration test is performed on the dye-sensitized photoelectric conversion elements 10 of Example 12, Comparative Example 3, and Comparative Example 8 and output. The characteristics were compared. The reliability acceleration test was performed in the same manner as described above.

FIG. 11 shows each I when the dye-sensitized photoelectric conversion element 10 of Example 12, Comparative Example 3 and Comparative Example 8 immediately before the start of measurement is irradiated with simulated sunlight (AM1.5, 100 mW / cm ² ). It is a basic diagram which showed -V output characteristic.

  As shown in FIG. 11, the IV output characteristics of the dye-sensitized photoelectric conversion elements 10 are substantially the same as the IV output characteristics of the dye-sensitized photoelectric conversion elements 10 of Example 12 and Comparative Example 8. On the other hand, the IV output characteristics of the dye-sensitized photoelectric conversion element 10 of Comparative Example 2 showed characteristics that the short-circuit current density was low and the open-circuit voltage was slightly higher than the other two examples. The slight difference in the IV output characteristics between Example 12 and Comparative Example 8 and Comparative Example 3 occurred because the metal substrate 2 made of a different material was used, and thus the electrical characteristics were different. It is believed that there is.

FIG. 12 shows the case where the dye-sensitized photoelectric conversion element 10 of Example 12, Comparative Example 3 and Comparative Example 8 after irradiation for 258 hours from the start of measurement was irradiated with artificial sunlight (AM1.5, 100 mW / cm ² ). FIG. 5 is a schematic diagram comparing respective IV output characteristics. The storage conditions of the dye-sensitized photoelectric conversion element 10 were a temperature of 85 ° C. and a humidity of 0%.

  From FIG. 12, the IV output characteristics after 258 hours storage from the start of measurement of the dye-sensitized photoelectric conversion element 10 of Example 12 showed almost no change compared to immediately before the start of measurement, whereas Comparative Example 3 As for the IV output characteristics of the dye-sensitized photoelectric conversion element 10 of Comparative Example 8 after 258 hours storage, although the short-circuit current density value increases compared to immediately before the start of measurement, the open-circuit voltage value is greatly increased. It changed in the downward direction. Further, after storage for 258 hours from the production, the IV output characteristics of the dye-sensitized photoelectric conversion elements 10 of Comparative Example 3 and Comparative Example 8 both showed similar characteristics.

  As a result, the metal substrate 2 and the conductive diamond-like carbon film 4 are bound via the conductive film 11, and the catalyst layer 3 is further bound on the conductive diamond-like carbon film 4. In particular, the dye-sensitized photoelectric conversion element 10 using the counter electrode 1 having the following characteristics is 258 hours from the time when the material constituting the metal substrate 2 is stainless steel and the material constituting the conductive film 11 is a titanium-based material. It became clear that the output characteristics did not change even after the lapse. Thereby, the metal substrate 2 and the conductive diamond-like carbon film 4 are bound via the conductive film 11, and the catalyst layer 3 is further bound and provided on the conductive diamond-like carbon film 4. The dye-sensitized photoelectric conversion element 10 using the counter electrode 1 has a dye-sensitized dye using the counter electrode 1 having a configuration in which the metal substrate 2 and the catalyst layer 3 are bonded via the conductive diamond-like carbon film 4. In particular, when the material constituting the metal substrate 2 is stainless special steel and the material constituting the conductive curtain 11 is a titanium-based material than the photoelectric conversion element 10, stable power generation with less fluctuation of the fill factor with time is possible. It was shown to be possible.

In order to further investigate the change over time in the output characteristics of the dye-sensitized photoelectric conversion elements 10 of Example 12, Comparative Example 3 and Comparative Example 8, the dye-sensitized photoelectric conversion elements 10 of Example 12, Comparative Example 3 and Comparative Example 8 were used. It measured about the change of the value of the photoelectric conversion efficiency with respect to the elapsed time from preparation of this. The storage conditions of the dye-sensitized photoelectric conversion element 10 are the same as those in the measurement of the above-described IV output characteristics, and the measurement conditions are continuously simulated sunlight (AM1.5, 100 mW / cm from the start of measurement to 258 hours). ² ) was irradiated and measured.

  Table 5 shows the measurement results of the photoelectric conversion efficiency after 75 hours and 258 hours of the dye-sensitized photoelectric conversion elements 10 of Example 12, Comparative Example 3 and Comparative Example 8, and the photoelectric conversion efficiency values immediately before the start of measurement. Each is normalized and shown as 100.

図１３は、実施例１２、比較例３および比較例８の色素増感光電変換素子１０における光電変換効率の経過時間に対する測定結果を、測定開始直前の光電変換効率をそれぞれ１００として正規化して示した略線図である。

FIG. 13 shows the measurement results with respect to the elapsed time of the photoelectric conversion efficiency in the dye-sensitized photoelectric conversion elements 10 of Example 12, Comparative Example 3 and Comparative Example 8, normalized with the photoelectric conversion efficiency immediately before the start of measurement as 100, respectively. FIG.

  From Table 5 and FIG. 13, the photoelectric conversion efficiency in the dye-sensitized photoelectric conversion element 10 of Comparative Example 3 and Comparative Example 8 is lower than that at the beginning of manufacture after 258 hours from the preparation. On the other hand, the photoelectric conversion efficiency in the dye-sensitized photoelectric conversion element 10 of Example 12 suddenly increased by 100 hours from the production and then gradually decreases, but even after 258 hours from the start of measurement, the photoelectric conversion efficiency is increased. It was shown that the conversion efficiency was maintained higher than that immediately before the start of measurement.

  As a result, the dye-sensitized photoelectric conversion element 10 using the counter electrode 1 having the structure in which the catalyst layer 3 is directly bonded on the metal substrate 2 is subjected to photoelectric conversion after storage for 258 hours from immediately before the start of measurement. While the efficiency is lowered, the metal substrate 2 and the conductive diamond-like carbon film 4 are bound via the conductive film 11, and the catalyst layer 3 is further bound on the conductive diamond-like carbon film 4. It was revealed that the dye-sensitized photoelectric conversion element 10 using the counter electrode 1 having the configuration provided as described above has a higher photoelectric conversion efficiency than that immediately before the start of measurement after storage for 258 hours.

  In particular, when the metal substrate 2 is a stainless special steel plate, the dye sensitization using the counter electrode 1 having a configuration in which the metal substrate 2 and the catalyst layer 3 are bound via the conductive diamond-like carbon film 4 is used. The photoelectric conversion element 10 has a photoelectric conversion efficiency lower than that immediately before the start of measurement after storage for 258 hours, whereas the metal substrate 2 and the conductive diamond-like carbon film 4 are connected via the conductive film 11. The dye-sensitized photoelectric conversion element 10 using the counter electrode 1 having a configuration in which the catalyst layer 3 is further provided on the conductive diamond-like carbon film 4 is obtained after storage for 258 hours from the time immediately before the start of measurement. It became clear that photoelectric conversion efficiency became high.

  This is because the surface of the metal substrate 2 is modified by forming the low resistance conductive film 11 on the metal substrate 2, and at the same time, the conductive film 11 is formed on the metal substrate 2 and the conductive diamond. By providing between the like carbon film 4, the direct current resistance value between the metal substrate 2 and the conductive diamond-like carbon film 4 is reduced. This decrease in the DC resistance value is considered to have greatly improved the conductivity of the counter electrode 1 and led to an improvement in photoelectric conversion efficiency. In particular, when the metal substrate 2 is a special stainless steel plate, it is considered that the electrical and mechanical affinity between the surface on the metal substrate 2 and the conductive diamond-like carbon film 4 is low. By forming the TiN film, the surface of the metal substrate 2 is modified, and the electrical and mechanical affinity between the conductive diamond-like carbon film 4 and the metal substrate 2 is improved. As a result, the contact resistance at the interface between the two decreases and the conductivity is improved, which is considered to have led to an improvement in photoelectric conversion efficiency.

  As described above, the dye-sensitized photoelectric conversion element 10 according to the fourth embodiment has the same advantages as those of the second embodiment, and the counter electrode 1 of the dye-sensitized photoelectric conversion element 10 is Since the metal substrate 2 and the conductive diamond-like carbon film 4 are bonded via the conductive film 11, and the catalyst layer 3 is further provided on the conductive diamond-like carbon film 4, the conductive diamond is formed. Even if the metal substrate 2 is made of a material that does not have a high affinity with the like carbon film 4, the conductive film 11 is formed on the film forming surface of the conductive diamond like carbon film 4, and the conductive film 11 is modified. The electrical and mechanical affinity between the diamond-like carbon film 4 and the metal substrate 2 is improved, and the photoelectric conversion performance is dramatically improved. In addition, since the electrical and mechanical compatibility between the two is improved, the deterioration of the counter electrode 1 with time can be effectively suppressed. As described above, according to the second embodiment, even if the material constituting the metal substrate 2 is a material having a low affinity with the conductive diamond-like carbon, the photoelectric conversion efficiency is high and the material is used for a long time. However, a high-performance dye-sensitized photoelectric conversion element 10 with little performance deterioration can be obtained.

  As described above, according to the fourth embodiment, the same advantage as that of the dye-sensitized photoelectric conversion element 10 according to the second embodiment is obtained, and the metal substrate 2 is compatible with the conductive diamond-like carbon. Even if it is made of a material that is not high, a high-performance dye-sensitized photoelectric conversion element 10 that can obtain high photoelectric conversion efficiency can be obtained.

Although the embodiments and examples have been specifically described above, the present disclosure is not limited to the above-described embodiments and examples, and various modifications based on the technical idea of the present disclosure are possible. .
For example, the numerical values, structures, configurations, shapes, materials, and the like given in the above-described embodiments and examples are merely examples, and different numerical values, structures, configurations, shapes, materials, etc. are used as necessary. Also good.

In addition, this technique can also take the following structures.
(1) A porous electrode, a counter electrode, an electrolyte layer between the porous electrode and the counter electrode, and the counter electrode is a metal substrate and a conductive diamond-like carbon provided on the metal substrate A photoelectric conversion element comprising a film and a catalyst layer provided on the conductive diamond-like carbon film.
(2) The photoelectric conversion element according to (1), wherein the metal substrate is made of any one of aluminum, an aluminum alloy, and stainless steel.
(3) The photoelectric conversion element according to (1) or (2), wherein the catalyst layer is a conductive carbon layer.
(4) The photoelectric conversion element according to any one of (1) to (3), wherein a conductive film is provided on the metal substrate, and a conductive diamond-like carbon film is provided on the conductive film.
(5) The photoelectric conversion element according to any one of (1) to (4), wherein the conductive film is made of a titanium-based material.
(6) The photoelectric conversion element according to any one of (1) to (5), wherein the titanium-based material is TiN or TiCN.
(7) The method according to any one of (1) to (6), further including a sealing body that seals the electrolyte of the electrolyte layer, wherein the sealing body is in close contact with the conductive diamond-like carbon film. Photoelectric conversion element.
(8) The photoelectric conversion element according to (7), wherein the sealing body includes a UV curable resin and a thermosetting resin.
(9) The photoelectric conversion element according to any one of (1) to (8), wherein the photoelectric conversion element is a dye-sensitized photoelectric conversion element in which a photosensitizing dye is adsorbed on the porous electrode.
(10) When producing a photoelectric conversion element having an electrolyte layer between a porous electrode, a counter electrode, and the porous electrode and the counter electrode, a conductive diamond-like carbon film is formed on a metal substrate; A method for producing a photoelectric conversion element, wherein the counter electrode is formed by forming a catalyst layer on the conductive diamond-like carbon film.
(11) The method for producing a photoelectric conversion element according to (10), wherein the metal substrate is made of any one of aluminum, an aluminum alloy, and stainless steel.
(12) The method for producing a photoelectric conversion element according to (10) or (11), wherein the catalyst layer is a conductive carbon layer.
(13) The method for producing a photoelectric conversion element according to any one of (10) to (12), wherein the conductive diamond-like carbon film is formed after forming the conductive film on the metal substrate.
(14) The method for manufacturing a photoelectric conversion element according to (13), wherein the conductive film is made of a titanium-based material.
(15) When manufacturing a photoelectric conversion element further having a sealing body for sealing the electrolyte of the electrolyte layer, the sealing body is thermally cured by contacting the sealing body with a conductive diamond-like carbon film. The method for producing a photoelectric conversion element according to any one of the above (10) to (14), wherein the is adhered to the conductive diamond-like carbon film.
(16) The method for manufacturing a photoelectric conversion element according to (15), wherein the sealing body includes a UV curable resin and a thermosetting resin, and the sealing body is thermally cured by irradiation with UV light.
(17) having at least one photoelectric conversion element, having a porous electrode, a counter electrode, and an electrolyte layer between the porous electrode and the counter electrode, wherein the counter electrode is formed on a metal substrate and the metal substrate; An electronic device which is a photoelectric conversion element having a conductive diamond-like carbon film and a catalyst layer provided on the conductive diamond-like carbon film.
(18) A counter electrode for a photoelectric conversion element, comprising a metal substrate, a conductive diamond-like carbon film provided on the metal substrate, and a catalyst layer provided on the conductive diamond-like carbon film.
(19) having at least one photoelectric conversion element, wherein the photoelectric conversion element has a porous electrode, a counter electrode, and an electrolyte layer between the porous electrode and the counter electrode, the counter electrode being a metal substrate And a building which is a photoelectric conversion element having a conductive diamond-like carbon film provided on the metal substrate and a catalyst layer provided on the conductive diamond-like carbon film.
(20) The building according to (19), wherein at least one of the photoelectric conversion element and / or the photoelectric conversion element module is sandwiched between two transparent plates.

DESCRIPTION OF SYMBOLS 1 ... Counter electrode, 2 ... Metal substrate, 3 ... Catalyst layer, 4 ... Conductive diamond-like carbon film, 5 ... Transparent substrate, 6 ... Transparent electrode, 7 ... Porous electrode, 8 ... Electrolyte layer, 9 ... Sealing body, 10 ... Dye-sensitized photoelectric conversion element, 11 ... Conductive film.

Claims (20)

A porous electrode;
With the counter electrode,
Having an electrolyte layer between the porous electrode and the counter electrode;
The counter electrode is
A metal substrate;
A conductive diamond-like carbon film provided on the metal substrate;
A photoelectric conversion element having a catalyst layer provided on the conductive diamond-like carbon film.   The photoelectric conversion element according to claim 1, wherein the metal substrate is made of any one of aluminum, an aluminum alloy, and stainless steel.   The photoelectric conversion element according to claim 2, wherein the catalyst layer is a conductive carbon layer.   The photoelectric conversion element according to claim 3, wherein a conductive film is provided on the metal substrate, and a conductive diamond-like carbon film is provided on the conductive film.   The photoelectric conversion element according to claim 4, wherein the conductive film is made of a titanium-based material.   The photoelectric conversion element according to claim 5, wherein the titanium-based material is TiN or TiCN. It further has a sealing body that seals the electrolyte of the electrolyte layer,
The photoelectric conversion element according to claim 1, wherein the sealing body is in close contact with the conductive diamond-like carbon film.   The photoelectric conversion element according to claim 7, wherein the sealing body includes a UV curable resin and a thermosetting resin.   The photoelectric conversion element according to claim 1, wherein the photoelectric conversion element is a dye-sensitized photoelectric conversion element in which a photosensitizing dye is adsorbed on the porous electrode. A porous electrode;
With the counter electrode,
When manufacturing a photoelectric conversion element having an electrolyte layer between the porous electrode and the counter electrode,
A conductive diamond-like carbon film is formed on a metal substrate,
A method for producing a photoelectric conversion element, wherein the counter electrode is formed by forming a catalyst layer on the conductive diamond-like carbon film.   The method of manufacturing a photoelectric conversion element according to claim 10, wherein the metal substrate is made of any one of aluminum, an aluminum alloy, and stainless steel.   The method for producing a photoelectric conversion element according to claim 11, wherein the catalyst layer is a conductive carbon layer.   The method for producing a photoelectric conversion element according to claim 10, wherein the conductive diamond-like carbon film is formed after forming a conductive film on a metal substrate.   The method for manufacturing a photoelectric conversion element according to claim 13, wherein the conductive film is made of a titanium-based material. When producing a photoelectric conversion element further having a sealing body for sealing the electrolyte of the electrolyte layer,
The method for producing a photoelectric conversion element according to claim 10, wherein the sealing body is brought into close contact with the conductive diamond-like carbon film by bringing the sealing body into contact with the conductive diamond-like carbon film and thermosetting.   The method of manufacturing a photoelectric conversion element according to claim 15, wherein the sealing body includes a UV curable resin and a thermosetting resin, and the sealing body is thermally cured by irradiating UV light. Having at least one photoelectric conversion element;
A porous electrode;
With the counter electrode,
Having an electrolyte layer between the porous electrode and the counter electrode;
The counter electrode is
A metal substrate;
A conductive diamond-like carbon film provided on the metal substrate;
An electronic device which is a photoelectric conversion element having a catalyst layer provided on the conductive diamond-like carbon film. A metal substrate;
A conductive diamond-like carbon film provided on the metal substrate;
A counter electrode for a photoelectric conversion element, comprising: a catalyst layer provided on the conductive diamond-like carbon film. Having at least one photoelectric conversion element;
The photoelectric conversion element is
A porous electrode;
With the counter electrode,
Having an electrolyte layer between the porous electrode and the counter electrode;
The counter electrode is
A metal substrate;
A conductive diamond-like carbon film provided on the metal substrate;
A building which is a photoelectric conversion element having a catalyst layer provided on the conductive diamond-like carbon film.   The building according to claim 19, wherein at least one of the photoelectric conversion element and / or the photoelectric conversion element module is sandwiched between two transparent plates.

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