JP4334960B2 - Carbon electrode and electrode and dye-sensitized solar cell comprising the same - Google Patents

Description

  The present invention relates to a carbon electrode, an electrode including the carbon electrode, and a dye-sensitized solar cell.

  In recent years, various developments of solar cells have been promoted with increasing interest in global warming and energy problems. Among the solar cells, since the dye-sensitized solar cell has been proposed by Gretzell et al. (See, for example, Patent Document 1 below), the material used is inexpensive and can be manufactured by a relatively simple process. Therefore, its practical application is expected.

As a counter electrode of such a dye-sensitized solar cell, for example, a so-called Pt-supported TCO glass substrate (Transparent Conductive Oxide Coated) having a configuration in which a transparent conductive film in which catalyst particles such as Pt are attached is coated on a transparent substrate. Glass) and Pt-supporting conductive synthetic resin films are known (see, for example, Patent Document 1 below). Examples of the TCO glass substrate include a compound (ITO) -coated glass composed of 95% indium oxide and 5% tin oxide, a fluorine-doped SnO ₂ (FTO) -coated glass, and the like. For example, a functional PET film.

However, in addition to the counter electrode described above, a reduction reaction (for example, reducing I ₃ ⁻ to I ⁻ ) reduces an oxidized form of a redox pair (for example, I ₃ ⁻ / I ⁻ etc.) present in the electrolyte to a reduced form. From the viewpoint of practical use of dye-sensitized solar cells, the development of a counter electrode that has excellent electrode characteristics that allow a reduction reaction to proceed rapidly, is easy to manufacture, and is inexpensive. It is important and various studies have been conducted so far.

  For example, as a study as described above, carbon black particles, graphite particles having a flat shape (average particle size: 1 to 20 μm), and anatase-type titanium oxide particles (see, for example, FIG. 3 of the above document) A porous carbon electrode formed as a constituent material has been proposed, and a dye-sensitized solar cell using this as a counter electrode has also been proposed (for example, see Non-Patent Document 1 below).

  Since the porous carbon electrode can take the electrolyte solution into the pores inside the electrode, the electrode area should be larger than the counter electrode made of the Pt-supported TCO glass substrate described above. Has the advantage that it is easy to form, is light and chemically stable, and can be easily formed into various shapes at low cost.

Japanese Patent No. 2664194 (page 3, FIG. 1) Andreas Kay, Michael Gratzel, "Low cost photovoltaic modules based on dye sensitized nanocrystalline titanium dioxide and carbon powder", Solar Energy Materials and Solar Cells, 44, Elsevier Science, 1996, p.99-117

However, compared with the dye-sensitized solar cell provided with the above-described Pt-supported TCO glass substrate as a counter electrode, the present inventors provide a dye-sensitized solar cell provided with the conventional carbon electrode as a counter electrode, This is particularly obtained when the light receiving surface is irradiated with a relatively high power when operated under a practical operating environment in which the power of the light irradiated on the light receiving surface fluctuates within a range of 100 mW / cm ^{2 at} the maximum. It has been found that the short-circuit current density Jsc [mA · cm ⁻² ] and the energy conversion efficiency η [%] are low and still insufficient.

For example, a dye-sensitized solar cell provided with the above-described conventional carbon electrode as a counter electrode, when irradiated with 10 mW / cm ² of pseudo-sunlight, is a short circuit substantially equivalent to a battery provided with a Pt-supported TCO glass substrate as a counter electrode. Although the current density Jsc and the energy conversion efficiency η can be obtained, the degree of decrease in the short-circuit current density Jsc and the energy conversion efficiency η when the pseudo-sunlight of 100 mW / cm ² is irradiated indicates that the Pt-supported TCO glass substrate The present inventors have confirmed that the size is larger than that of a battery provided as a counter electrode.

  The dye-sensitized solar cell provided with the above-described conventional carbon electrode as a counter electrode has a problem that the battery characteristics obtained in the initial stage are deteriorated as it is repeatedly used. That is, there is a problem that sufficient durability cannot be obtained.

This invention is made | formed in view of the subject which the said prior art has, and aims at providing the carbon electrode which can advance the oxidation-reduction reaction of an electrode surface rapidly.
Another object of the present invention is to provide an electrode that is equipped with the carbon electrode and that can rapidly advance the oxidation-reduction reaction on the surface of the electrode and that has excellent durability.
Furthermore, the present invention includes the carbon electrode or the electrode as a counter electrode, and can obtain excellent energy conversion efficiency even when the power of the irradiated light fluctuates within a range of 100 mW / cm ^{2 at} the maximum. An object of the present invention is to provide a dye-sensitized solar cell that can be used and can also have excellent durability.

  As a result of intensive studies to achieve the above object, the inventors of the present invention have a great influence on the above-mentioned problem that the ion diffusion rate inside the electrode is not sufficiently obtained. I found out.

  As a result of further investigations aimed at improving the electrical conductivity of the electrode, the present inventors have found that the conventional carbon electrode has a specific size instead of a graphite-like particle having a flat shape. It has been found that using columnar particles made of a conductive carbon material having a thickness is extremely effective for improving the diffusion rate of ions inside the electrode without losing the advantages described above. The invention has been reached.

That is, the present invention is a porous carbon electrode having pores,
It contains at least carbon black-like particles, particles made of columnar conductive carbon material, and anatase-type titanium oxide particles as constituent materials,
Particles made of a columnar conductive carbon material have a bottom diameter of 50 to 500 nm and a height of 1 to 20 μm,
The contained mass W1 of the carbon black-like particles, the contained mass W2 of the particles made of the columnar conductive carbon material, and the contained mass W3 of the titanium oxide particles are represented by the following formula (1) and the following formula (2). Meeting the requirements at the same time,
A carbon electrode is provided.
0.05 ≦ (W1 / W2) ≦ 0.4 (1)
0.05 ≦ {W3 / (W1 + W2)} ≦ 0.4 (2)

  In the present invention, instead of the graphite-like particles having a flat plate shape used in the conventional carbon electrode described above, particles made of a columnar conductive carbon material having the above specific size are formed. By using it as a material, the diffusion rate of ions inside the electrode of the obtained carbon electrode can be improved.

  Although the detailed mechanism for obtaining the above effect has not been clearly elucidated, the present inventors consider that it will be described below with reference to FIGS. FIG. 1 is a perspective view schematically showing the internal structure of a counter electrode provided in the dye-sensitized solar cell of the present invention. FIG. 14 is a perspective view schematically showing the internal structure of the counter electrode provided in the above-described conventional dye-sensitized solar cell.

That is, the present inventors, as shown in FIG. 14, the interior of the pore structure of the conventional carbon electrode E _B, since it is formed by the material comprising a bulky flat graphite particles P _B, The internal path (path for movement of chemical species) formed by connecting the pores becomes relatively long. Therefore, even if an electrolyte (liquid electrolyte or gel electrolyte) is taken into the electrode, the oxidant Ox and the reductant Re involved in the oxidation-reduction reaction on the electrode surface (one of which becomes a reactant and the other becomes a product) It is considered difficult to quickly diffuse between the electrode surface and the electrolyte bulk.

The present inventors have contrast, as shown in FIG. 1, the interior of the pore structure of the carbon electrode E _A of the present invention, relatively bulky low columnar conductive carbon material consisting of particles (hereinafter, need Accordingly, the internal path is relatively short. For this reason, it is considered that the oxidant Ox and the reductant Re involved in the redox reaction on the electrode surface can be easily diffused quickly between the electrode surface and the electrolyte bulk. Further, it is considered that moderately sized pores effective for the movement of the oxidant Ox and the reductant Re are formed by mixing the columnar particles satisfying the size condition described above.

  As described above, the carbon electrode of the present invention improves the diffusion rate in the electrode of the oxidant Ox and the reductant Re involved in the oxidation-reduction reaction that proceeds on the electrode surface, as compared with the conventional carbon electrode. This reaction can proceed promptly.

  In addition, the carbon electrode of the present invention is easy to ensure a large electrode area as compared with the electrode made of the conventional TCO substrate described above, is lightweight and chemically stable, and is desired at a low cost. It can be easily formed into a shape.

Therefore, when the electrode having the structure including at least the carbon electrode of the present invention (or the carbon electrode of the present invention) is used as a counter electrode of the dye-sensitized solar cell, it is contained in the electrolyte as compared with the conventional carbon electrode described above. A reduction reaction (for example, a reduction reaction for reducing I ₃ ⁻ to I ⁻ ) by reacting electrons with an oxidized form of an oxidation-reduction pair (eg, I ₃ ⁻ / I ⁻ etc.) contained in And high energy conversion efficiency can be obtained. Moreover, since the carbon electrode of the present invention is lightweight and can be easily formed into a desired shape, a compact and lightweight dye-sensitized solar cell can be easily constructed at low cost.

  In the carbon electrode of the present invention, generation of minute cracks and peeling from the substrate are sufficiently prevented. Thus, although the detailed mechanism about the generation | occurrence | production of a micro crack fully prevented and the generation | occurrence | production of peeling from a board | substrate fully prevented is not elucidated clearly, the present inventors are the present invention. It is assumed that the carbon electrode contains particles made of columnar conductive carbon material, so that the internal stress after firing is reduced compared to the conventional carbon electrode containing graphite-like particles. ing. Therefore, if an electrode having at least the carbon electrode of the present invention (or the carbon electrode of the present invention) is used as the counter electrode of the dye-sensitized solar cell, it is compared with the conventional dye-sensitized solar cell described above. And a dye-sensitized solar cell having excellent durability.

  Here, in the present invention, the “columnar particles” in the “particles made of a columnar conductive carbon material” may be any particles that satisfy the above-mentioned size conditions, and between the two bottom surfaces. In addition to particles having a geometrically strict “columnar” shape with side surfaces formed, particles that can be considered generally columnar are also included. Therefore, in the present invention, the columnar particles may have irregularities on the bottom surface and side surfaces, for example. Also, the “bottom diameter” in the “bottom diameter” is perpendicular to the central axis when a columnar particle is approximated to a particle having a geometrically exact “columnar” shape when there is no bottom at the end of the particle. The diameter of a simple cross section is shown. Further, the diameter in the “bottom diameter” indicates an average distance between two intersections where a straight line passing through the geometric center of gravity of the bottom surface (cross section) intersects the outer edge of the bottom surface (cross section). The “height” indicates a distance between two bottom surfaces in the case where a columnar particle is approximated to a particle having a geometrically strict “columnar” shape.

  In the present invention, when the diameter of the bottom surface of the columnar particles is less than 50 nm, the influence of the contact resistance between the particles on the electron conduction is increased, so that the electron conductivity is lowered and the above-described effects cannot be obtained. In addition, when the diameter of the bottom surface of the columnar particles exceeds 500 nm, the internal path in the carbon electrode becomes long, so that it is impossible to quickly diffuse the oxidant and the reductant, and the above-described effects can be obtained. become unable.

  In the present invention, if the height of the columnar particles is less than 1 μm, the influence of the contact resistance between the particles on the electron conduction is increased, so that the electron conductivity is lowered and the above-described effects cannot be obtained. In addition, when the height of the columnar particles exceeds 20 μm, it becomes difficult to uniformly mix the columnar particles and the particles constituting the other constituent material, resulting in a decrease in electronic conductivity and a decrease in mechanical strength. The above-mentioned operational effects cannot be obtained.

Furthermore, in the formula (1), when (W1 / W2) is less than 0.05, the electrode area is reduced, and therefore oxidation / reduction pairs (for example, I ₃ ⁻ / I ⁻ etc.) contained in the electrolyte are oxidized. The rate of a reduction reaction (for example, a reduction reaction for reducing I ₃ ⁻ to I ⁻ ) that obtains a reduced form by reacting electrons with the body is reduced, and the above-described effects cannot be obtained. Moreover, in Formula (1), when (W1 / W2) exceeds 0.4, the electrical conductivity is lowered, and the above-described effects cannot be obtained.

  Further, in the formula (2), when {W3 / (W1 + W2)} is less than 0.05, the mechanical strength of the carbon electrode itself is reduced, and the carbon electrode is partially or completely peeled off and / or the carbon electrode. Cracks in the inside occur and the above-mentioned effects cannot be obtained. Moreover, in Formula (2), when {W3 / (W1 + W2)} exceeds 0.4, the electron conductivity is lowered, and the above-described effects cannot be obtained.

  Further, in this specification, “carbon black-like particles” means carbon black particles (amorphous, crystallized, and amorphous and crystallized structures are mixed). Carbon aerogel particles (amorphous, crystallized, and a mixture of amorphous and crystallized structures), and carbon 2 shows a mixture of black particles and carbon airgel particles. The shape of the carbon black particles is not particularly limited, and may be, for example, hollow particles.

  Further, in the present specification, “graphite-like particles” are (i) graphite particles, (ii) those obtained by swelling between layers of graphite particles, and (iii) a state in which other elements are incorporated between the layers of graphite particles. And (iv) a mixture obtained by arbitrarily mixing at least two kinds of particles among the above (i) to (iii).

Further, the present invention is a porous carbon electrode having pores,
Carbon black-like particles, particles made of columnar conductive carbon material, and conductive oxide particles having a lower electrical resistivity than anatase-type titanium oxide particles, at least as constituent materials,
Particles made of a columnar conductive carbon material have a bottom diameter of 50 to 500 nm and a height of 1 to 20 μm,
The content mass W1 of the carbon black-like particles, the content mass W2 of the particles made of the columnar conductive carbon material, and the content mass W4 of the conductive oxide particles are expressed by the following formula (3) and the following formula (4). Meet the requirements
A carbon electrode is provided.
0.05 ≦ (W1 / W2) ≦ 0.4 (3)
0.05 ≦ {W4 / (W1 + W2)} ≦ 0.4 (4)

  The carbon electrode described above uses the columnar particles described above in place of the graphite-like particles having a flat plate shape used in the conventional carbon electrode, and is further used in the conventional carbon electrode. Instead of the anatase type titanium oxide particles, conductive oxide particles having a lower electrical resistivity than the titanium oxide particles are used as a constituent material. Thereby, while improving the diffusion rate of the ion inside the electrode of the carbon electrode obtained, the electrical conductivity of a carbon electrode can be improved.

  As a result, compared to conventional carbon electrodes, the diffusion rate of the oxidant and reductant involved in the oxidation-reduction reaction proceeding on the electrode surface can be improved and the electron transfer rate in the electrode is improved. Therefore, the oxidation-reduction reaction that proceeds on the electrode surface can be rapidly advanced.

  In addition, this type of carbon electrode is also easy to secure a wide electrode area as compared with the electrode made of the above-described conventional TCO substrate, is light and chemically stable, and is also desired at a low cost. It can be easily formed into a shape.

Therefore, if an electrode having a structure including at least this type of carbon electrode (or the carbon electrode of the present invention) is used as a counter electrode of a dye-sensitized solar cell, it is contained in the electrolyte as compared with the conventional carbon electrode described above. A reduction reaction (for example, a reduction reaction for reducing I ₃ ⁻ to I ⁻ ) by reacting electrons with an oxidized form of an oxidation-reduction pair (eg, I ₃ ⁻ / I ⁻ etc.) contained in And high energy conversion efficiency can be obtained. Moreover, since the carbon electrode of the present invention is lightweight and can be easily formed into a desired shape, a compact and lightweight dye-sensitized solar cell can be easily constructed at low cost.

  This type of carbon electrode of the present invention can sufficiently prevent the occurrence of minute cracks and peeling from the substrate. Thus, although the detailed mechanism about the generation | occurrence | production of a micro crack fully prevented and the generation | occurrence | production of peeling from a board | substrate fully prevented is not elucidated clearly, the present inventors are the present invention. It is assumed that the carbon electrode contains particles made of columnar conductive carbon material, so that the internal stress after firing is reduced compared to the conventional carbon electrode containing graphite-like particles. ing. Therefore, if an electrode having at least the carbon electrode of the present invention (or the carbon electrode of the present invention) is used as the counter electrode of the dye-sensitized solar cell, it is compared with the conventional dye-sensitized solar cell described above. And a dye-sensitized solar cell having excellent durability.

  Here, also in the case of this type of carbon electrode, when the diameter of the bottom surface of the columnar particles is less than 50 nm, the influence of the contact resistance between the particles on the electron conduction increases, so the electron conductivity decreases and the above-described effects are obtained. You will not be able to get. In addition, when the diameter of the bottom surface of the columnar particles exceeds 500 nm, the internal path in the carbon electrode becomes long, so that it is impossible to quickly diffuse the oxidant and the reductant, and the above-described effects can be obtained. become unable.

  On the other hand, when the height of the columnar particles is less than 1 μm, the influence of the contact resistance between the particles on the electron conduction becomes large, so that the electron conductivity is lowered and the above-described effects cannot be obtained. In addition, when the height of the columnar particles exceeds 20 μm, it becomes difficult to uniformly mix the columnar particles and the particles constituting the other constituent material, resulting in a decrease in electronic conductivity and a decrease in mechanical strength. The above-mentioned operational effects cannot be obtained.

Further, in the formula (3), when (W1 / W2) is less than 0.05, the electrode area is reduced, and therefore oxidation / reduction pairs (for example, I ₃ ⁻ / I ⁻ etc.) contained in the electrolyte are oxidized. The rate of a reduction reaction (for example, a reduction reaction for reducing I ₃ ⁻ to I ⁻ ) that obtains a reduced form by reacting electrons with the body is reduced, and the above-described effects cannot be obtained. Moreover, in Formula (1), when (W1 / W2) exceeds 0.4, the electrical conductivity is lowered, and the above-described effects cannot be obtained.

  In addition, in the formula (4), when {W3 / (W1 + W2)} is less than 0.05, the mechanical strength of the carbon electrode itself is lowered, and part or all of the carbon electrode is peeled off and / or the carbon electrode. Cracks in the inside occur and the above-mentioned effects cannot be obtained. Moreover, in Formula (4), when {W3 / (W1 + W2)} exceeds 0.4, the electron conductivity is lowered, and the above-described effects cannot be obtained.

  The use of the carbon electrode of the present invention is not particularly limited and is preferably used as a counter electrode of a dye-sensitized solar cell, but can also be used as an electrode other than the counter electrode of the dye-sensitized solar cell. For example, other batteries (for example, air batteries, manganese dry batteries), various processes in the electrolytic industry (for example, salt electrolysis, electrolytic refining of aluminum, calcium, magnesium, alkali metals, etc.), or electrolytic steel making, anode for electrolytic synthesis May be used as

Further, the present invention is an electrode used as a counter electrode of a dye-sensitized solar cell,
A substrate,
Any of the carbon electrodes of the present invention described above;
A binder layer disposed between the substrate and the carbon electrode, for integrating the substrate and the carbon electrode;
At least,
The binder layer contains at least carbon black-like particles, particles made of graphite, and anatase-type titanium oxide particles as constituent materials, and
The particles made of graphite have an average particle size of 1 to 20 μm,
An electrode is provided.

  The durability can be further improved by adopting a configuration in which the binder layer having the above-described configuration is further disposed between the substrate and the carbon electrode of the present invention described above. Thereby, the oxidation-reduction reaction on the electrode surface can be rapidly advanced, and an electrode excellent in durability can be provided.

  Said binder layer has the structure which contains the particle | grains which consist of graphite instead of the particle | grains which consist of the columnar electroconductive carbon material (carbon fiber etc.) contained in the carbon electrode of this invention. The above-mentioned effect (further improvement in durability) is obtained when the binder layer containing particles made of graphite has better binding properties to the substrate than the carbon electrode (carbon electrode of the present invention). The present inventors consider that this is a factor that has been described. Examples of the substrate include a transparent substrate, a substrate having a transparent conductive film formed on the transparent substrate (bonded to the carbon electrode on the transparent conductive film side), a substrate made of a transparent conductive material, metal Preferable examples include a substrate and a substrate having a structure in which a metal film is formed on a transparent substrate (bonded to a carbon electrode on the metal film side).

  Here, if the average particle diameter of the particles made of graphite is less than 1 μm, the influence of the contact resistance between the particles on the electron conduction is increased, so that the electron conductivity is lowered and the above-mentioned effects cannot be obtained. On the other hand, if the average particle diameter of the particles made of graphite exceeds 20 μm, it becomes difficult to uniformly mix the particles made of graphite and the particles constituting other constituent materials, resulting in a decrease in electron conductivity and a decrease in mechanical strength. As a result, the above-described effects cannot be obtained.

  In addition, the use of the electrode of the present invention described above is not particularly limited and is preferably used as a counter electrode of a dye-sensitized solar cell, but can also be used as an electrode other than the counter electrode of the dye-sensitized solar cell. For example, other batteries (for example, air batteries, manganese dry batteries), various processes in the electrolytic industry (for example, salt electrolysis, electrolytic refining of aluminum, calcium, magnesium, alkali metals, etc.), or electrolytic steel making, anode for electrolytic synthesis May be used as

Furthermore, the present invention is an electrode used as a counter electrode of a dye-sensitized solar cell,
A substrate,
Any of the carbon electrodes of the present invention described above;
A binder layer disposed between the substrate and the carbon electrode, for integrating the substrate and the carbon electrode;
At least,
The binder layer contains at least carbon black-like particles, particles made of graphite, and conductive oxide particles having a lower electrical resistivity than anatase-type titanium oxide particles as constituent materials, and
The particles made of graphite have an average particle size of 1 to 20 μm,
An electrode is provided.

  Thus, instead of the anatase-type titanium oxide particles used in the electrode of the present invention described above, conductive oxide particles having a lower electrical resistivity than the titanium oxide particles are used as a constituent material. Even so, the durability can be further improved by further arranging the binder layer having the above-described configuration between the substrate and the carbon electrode of the present invention described above. Thereby, the oxidation-reduction reaction on the electrode surface can be rapidly advanced, and an electrode excellent in durability can be provided.

  Said binder layer has the structure which contains the particle | grains which consist of graphite instead of the particle | grains which consist of the columnar electroconductive carbon material (carbon fiber etc.) contained in the carbon electrode of this invention. The above-mentioned effect (further improvement in durability) is obtained when the binder layer containing particles made of graphite has better binding properties to the substrate than the carbon electrode (carbon electrode of the present invention). The present inventors consider that this is a factor that has been described. Examples of the substrate include a transparent substrate, a substrate having a transparent conductive film formed on the transparent substrate (bonded to the carbon electrode on the transparent conductive film side), a substrate made of a transparent conductive material, metal Preferable examples include a substrate and a substrate having a structure in which a metal film is formed on a transparent substrate (bonded to a carbon electrode on the metal film side).

  Here, if the average particle diameter of the particles made of graphite is less than 1 μm, the influence of the contact resistance between the particles on the electron conduction is increased, so that the electron conductivity is lowered and the above-mentioned effects cannot be obtained. On the other hand, if the average particle diameter of the particles made of graphite exceeds 20 μm, it becomes difficult to uniformly mix the particles made of graphite and the particles constituting other constituent materials, resulting in a decrease in electron conductivity and a decrease in mechanical strength. As a result, the above-described effects cannot be obtained.

  In addition, the use of the electrode of the present invention described above is not particularly limited and is preferably used as a counter electrode of a dye-sensitized solar cell, but can also be used as an electrode other than the counter electrode of the dye-sensitized solar cell. For example, other batteries (for example, air batteries, manganese dry batteries), various processes in the electrolytic industry (for example, salt electrolysis, electrolytic refining of aluminum, calcium, magnesium, alkali metals, etc.), or electrolytic steel making, anode for electrolytic synthesis May be used as

  Furthermore, the present invention includes a photoelectrode having a semiconductor electrode having a light receiving surface, a transparent electrode disposed adjacent to the light receiving surface, and a counter electrode, and the semiconductor electrode and the counter electrode are interposed via an electrolyte. A dye-sensitized solar cell disposed opposite to each other, wherein the counter electrode has at least one of the carbon electrodes of the present invention described above. To do.

Thus, even when the power of the irradiated light varies within a maximum range of 100 mW / cm ² by using the electrode having the structure including at least the carbon electrode of the present invention described above as a counter electrode, it is excellent. In addition, a dye-sensitized solar cell that can achieve high energy conversion efficiency and can also have excellent durability can be easily configured.

  Furthermore, the present invention includes a photoelectrode having a semiconductor electrode having a light receiving surface, a transparent electrode disposed adjacent to the light receiving surface, and a counter electrode, and the semiconductor electrode and the counter electrode are interposed via an electrolyte. A dye-sensitized solar cell disposed opposite to each other, wherein the counter electrode has at least one of the above-described electrodes of the present invention. .

Thus, even when the power of the irradiated light varies within a maximum range of 100 mW / cm ² by using the electrode having the structure including at least the electrode of the present invention described above as a counter electrode, it is excellent. A dye-sensitized solar cell that can obtain energy conversion efficiency and can also have excellent durability can be easily configured.

  Here, in the present invention, the “dye” refers to a metal complex dye and an organic dye. In addition, “electrolyte” refers to an electrolyte solution (hereinafter referred to as “electrolyte” as necessary), a gel obtained by adding a gelling agent to the electrolyte solution, and a solid electrolyte.

ADVANTAGE OF THE INVENTION According to this invention, the carbon electrode with high electronic conductivity which can advance the oxidation-reduction reaction of the electrode surface rapidly can be provided.
Moreover, according to this invention, the said carbon electrode is provided, the oxidation-reduction reaction of the electrode surface can be advanced rapidly, and the electrode excellent also in durability can be provided.
Further, according to the present invention, by providing the carbon electrode or the electrode as a counter electrode, an electron is reacted with an oxidant of a redox pair (for example, I ₃ ⁻ / I ⁻ etc.) contained in the electrolyte. Since a reduction reaction for obtaining a reductant (for example, a reduction reaction for reducing I ₃ ⁻ to I ⁻ ) can be rapidly advanced, the power of irradiated light varies within a maximum range of 100 mW / cm ^2. Even if it is a case, the dye-sensitized solar cell which can obtain the outstanding energy conversion efficiency and can also obtain the outstanding durability can be comprised.

  Hereinafter, preferred embodiments of the carbon electrode and the dye-sensitized solar cell of the present invention will be described in detail with reference to the drawings. In the following description, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

[First Embodiment]
FIG. 2 is a schematic cross-sectional view showing the basic configuration of the first embodiment of the dye-sensitized solar cell of the present invention. Note that the dye-sensitized solar cell 20 illustrated in FIG. 2 includes a preferred embodiment of the carbon electrode of the present invention as the counter electrode CE1.

  The dye-sensitized solar cell 20 shown in FIG. 2 mainly includes a photoelectrode 10, a counter electrode CE1, and an electrolyte E filled in a gap formed between the photoelectrode 10 and the counter electrode CE by a spacer S. Has been. 2 mainly includes a semiconductor electrode 2 having a light receiving surface F2 and a transparent electrode 1 disposed adjacent to the light receiving surface F2 of the semiconductor electrode 2. And the semiconductor electrode 2 is contacting the electrolyte E in the back surface F22 on the opposite side to the light-receiving surface F2.

  In this dye-sensitized solar cell 20, the sensitizing dye adsorbed in the semiconductor electrode 2 is excited by light that passes through the transparent electrode 1 and is applied to the semiconductor electrode 2, and the semiconductor electrode 2 is excited from this sensitizing dye. Electrons are injected into. The electrons injected in the semiconductor electrode 2 are collected in the transparent electrode 1 and taken out to the outside.

  The structure of the transparent electrode 1 is not specifically limited, The transparent electrode mounted in a normal dye-sensitized solar cell can be used. For example, the transparent electrode 1 shown in FIG. 2 has a configuration in which a so-called transparent conductive film 3 is coated on the semiconductor electrode 2 side of a transparent substrate 4 such as a glass substrate. As the transparent conductive film 3, a transparent electrode used for a liquid crystal panel or the like may be used.

Examples thereof include fluorine-doped SnO ₂ coated glass, ITO coated glass, ZnO: Al coated glass, and antimony-doped tin oxide (SnO ₂ —Sb). In addition, a transparent electrode obtained by doping cations or anions with different valences into tin oxide or indium oxide, or a metal electrode having a structure capable of transmitting light, such as a mesh shape or a stripe shape, provided on a substrate such as a glass substrate Good.

  As the transparent substrate 4, a transparent substrate used for a liquid crystal panel or the like may be used. Specific examples of the transparent substrate material include transparent glass substrates, materials that prevent the reflection of light by appropriately roughening the surface of the glass substrate, and materials that transmit light, such as a ground glass-like translucent glass substrate. Note that the material may not be glass as long as it transmits light, and may be a transparent plastic plate, a transparent plastic film, an inorganic transparent crystal, or the like.

The semiconductor electrode 2 shown in FIG. 2 is composed of an oxide semiconductor layer containing oxide semiconductor particles as a constituent material. The oxide semiconductor particles contained in the semiconductor electrode 2 are not particularly limited, and a known oxide semiconductor or the like can be used. As the oxide semiconductor, for example, TiO ₂ , ZnO, SnO ₂ , Nb ₂ O ₅ , In ₂ O ₃ , WO ₃ , ZrO ₂ , La ₂ O ₃ , Ta ₂ O ₅ , SrTiO ₃ , BaTiO _3, or the like is used. be able to. Among these oxide semiconductors, anatase TiO ₂ is preferable.

  The sensitizing dye contained in the semiconductor electrode 2 is not particularly limited as long as it is a dye having absorption in the visible light region and / or the infrared light region. More preferably, any material that emits electrons when excited by light having a wavelength of at least 200 nm to 10 μm may be used. As such a sensitizing dye, a metal complex, an organic dye, or the like can be used. Examples of the metal complex include metal phthalocyanines such as copper phthalocyanine and titanyl phthalocyanine, chlorophyll or derivatives thereof, hemin, ruthenium, osmium, iron and zinc complexes (for example, cis-dicyanate-N, N′-bis (2,2′-bipyridyl). -4,4'-dicarboxylate) ruthenium (II)) and the like. As the organic dye, metal-free phthalocyanine, cyanine dye, merocyanine dye, xanthene dye, triphenylmethane dye, and the like can be used.

In addition, the counter electrode CE1 is a reduction reaction (for example, I ₃ ⁻ is converted to I ⁻ to obtain a reduced form by reacting electrons with an oxidized form of a redox pair (for example, I ₃ ⁻ / I ⁻ etc.) contained in the electrolyte. The reduction reaction (reduction reaction to be reduced) is intended to proceed promptly and has the structure described above with reference to FIG. More specifically, it has a configuration described below.

  That is, the counter electrode CE1 includes a flat substrate 6, a transparent conductive film 7 formed on one surface of the substrate 6, and a carbon formed on the opposite surface of the transparent conductive film 7 that does not contact the substrate 6. The electrode 8 is constituted. The counter electrode CE1 is disposed such that the carbon electrode 8 is in contact with the electrolyte E. In FIG. 2, the counter electrode CE <b> 1 may have a configuration excluding the transparent conductive film 7, that is, a configuration including a flat substrate 6 and a carbon electrode 8 formed on one surface of the substrate 6. Further, the counter electrode CE1 may be configured by only the carbon electrode 8 itself when sufficient mechanical strength is obtained. In FIG. 2, the counter electrode CE <b> 1 is formed, for example, on a structure in which a metal film such as titanium or nickel is disposed instead of the transparent conductive film 7, that is, on a flat substrate 6 and one surface of the substrate 6. It is also possible to employ a configuration comprising a metal film and a carbon electrode 8 formed on the metal film.

  The substrate 6 is a support for the carbon electrode 8. The structure of the board | substrate 6 is not specifically limited, For example, you may use the thing similar to the transparent substrate 4 mentioned above. The substrate 6 may be a substrate made of a transparent conductive material or a metal plate. Furthermore, the transparent conductive film 7 may be formed of, for example, the same constituent material as the transparent conductive film 3 provided in the photoelectrode 10.

  The carbon electrode 8 has a structure in which 1) carbon black particles, particles made of columnar conductive carbon material, and anatase-type titanium oxide particles are used as constituent materials, or 2) carbon black particles A porous electrode having a structure in which particles made of a columnar conductive carbon material and conductive oxide particles having a lower electrical resistivity than anatase-type titanium oxide particles are formed as at least constituent materials. .

  The porous carbon electrode 8 holds the electrolyte E (liquid or gel electrolyte) in the pores in any of the above configurations 1) and 2). Further, in the case where the porous carbon electrode 8 has any of the above-described configurations 1) and 2), the particle made of the columnar conductive carbon material has a bottom diameter of 50 to 50 as described above. The height is 500 nm and the height is 1 to 20 μm.

  Further, in the case of the carbon electrode 8 having the configuration of 1), as described above, the content mass W1 of the carbon black particles, the content mass W2 of the particles made of the columnar conductive carbon material, and the anatase type oxidation The content mass W3 of the titanium particles simultaneously satisfies the conditions represented by the following formula (1) and the following formula (2).

0.05 ≦ (W1 / W2) ≦ 0.4 (1)
0.05 ≦ {W3 / (W1 + W2)} ≦ 0.4 (2)

  In the case of the carbon electrode 8 having the configuration 1), as described above, the content mass W1 of the carbon black-like particles, the content mass W2 of the particles made of the columnar conductive carbon material, and the conductive oxide It is preferable that the content mass W4 of the particles simultaneously satisfies the conditions represented by the following formula (3) and the following formula (4).

0.05 ≦ (W1 / W2) ≦ 0.4 (3)
0.05 ≦ {W4 / (W1 + W2)} ≦ 0.4 (4)

  The porous carbon electrode 8 is made of a columnar conductive carbon material from the viewpoint of more reliably obtaining the high ion diffusivity of the carbon electrode 8 regardless of the above-described configurations 1) and 2). The particles are preferably particles obtained by cutting carbon fibers (carbon fibers). The type and composition of the carbon fiber (carbon fiber) are not particularly limited as long as they satisfy the above-described columnar particle size conditions and have electrical conductivity. For example, it may be a so-called “pitch-based carbon fiber”, a “PAN-based carbon fiber”, or a “vapor-phase synthetic carbon fiber”, which contains other components. It may be.

However, from the viewpoint of more reliably obtaining the high electronic conductivity of the carbon electrode 8, the particles made of such a columnar conductive carbon material such as carbon fiber have an electric resistivity of 1 × 10 ⁻³ Ω · cm or less. It is preferable. When the electrical resistivity of the particles made of the columnar conductive carbon material exceeds 1 × 10 ⁻³ Ω · cm, the tendency to obtain sufficient electron conductivity becomes large.

Further, even when the porous carbon electrode 8 has the configuration of 2), the electrical conductivity of the conductive oxide particles can be obtained from the viewpoint of more reliably obtaining the high electronic conductivity of the carbon electrode 8 as described above. The resistivity is preferably 1 × 10 ⁻² Ω · cm or less. When the electrical resistivity of the conductive oxide particles exceeds 1 × 10 ⁻² Ω · cm, the tendency that it becomes difficult to obtain sufficient electronic conductivity increases.

Furthermore, as the conductive oxide particles satisfying the above conditions, Sn-doped In ₂ O ₃ , Zn-doped In ₂ O ₃ , Sb-doped SnO ₂ , F-doped SnO ₂ , Al-doped ZnO, Ga-doped ZnO, and In It is preferably at least one kind of particles selected from the group consisting of ₄ Sn ₃ O ₁₂ .

In addition, from the viewpoint of more reliably obtaining high electron conductivity of the carbon electrode 8, as a particle made of Sn-doped In ₂ O ₃ , a ratio between the number of Sn atoms and the number of In atoms contained in the compound is used. It is preferable that (the number of Sn atoms / the number of In atoms) is 0.01 to 0.25. In addition, as particles made of Zn-doped In ₂ O ₃ , the ratio of the number of Zn atoms and the number of In atoms contained in this compound (the number of Zn atoms / the number of In atoms) is 0.01 to It is preferably 0.25.

Further, as particles composed of Sb-doped SnO ₂ , the ratio of the number of Sb atoms and the number of Sn atoms contained in this compound (the number of Sb atoms / the number of Sn atoms) is 0.05 to 0.00. 55 is preferred. Further, as the particles made of F-doped SnO ₂ , the ratio of the number of F atoms and the number of O (oxygen atoms) contained in the compound (the number of F atoms / the number of O atoms) is 0. It is preferable that it is 05-0.50.

  Further, as the particles made of Al-doped ZnO, the ratio of the number of Al atoms and the number of Zn atoms contained in this compound (number of Al atoms / number of Zn atoms) is 0.01 to 0.25. It is preferable that In addition, as particles made of Ga-doped ZnO, the ratio of the number of Ga atoms and the number of Zn atoms contained in this compound (the number of Ga atoms / the number of Zn atoms) is 0.01 to 0.25. It is preferable that

  In addition, in the counter electrode CE1, which is a porous carbon electrode, for example, catalyst fine particles such as Pt fine particles may be dispersed and supported from the viewpoint of allowing the electrode reaction to proceed more rapidly.

  Furthermore, the electrolyte E is not particularly limited as long as it contains a redox species for reducing the dye after photoexcitation and electron injection into the semiconductor. For example, the electrolyte E may be a liquid electrolyte. It may be a gel electrolyte obtained by adding a known gelling agent (polymer or low molecular weight gelling agent).

  The solvent for the liquid electrolyte used for the electrolyte E is not particularly limited as long as it is a compound that can dissolve the solute component, but is electrochemically inert, has a high dielectric constant, and a low viscosity (and These mixed solvents are preferably dissolved in nitrile compounds such as methoxypropionitrile and acetonitrile, lactone compounds such as γ-butyrolactone and valerolactone, carbonate compounds such as ethylene carbonate and propylene carbonate, and the like. Can be mentioned.

As the solute of the liquid electrolyte used for the electrolyte E, a redox couple (I ₃ ⁻ / I ⁻ system electrolyte, Br ₃ ⁻ / Br ⁻⁾ capable of transferring electrons to the dye supported on the semiconductor electrode 2 and the counter electrode CE1. Based electrolytes, redox electrolytes such as hydroquinone / quinone based electrolytes), compounds having an effect of promoting the transfer of electrons, and the like. These may be included singly or in combination.

  More specifically, examples of the substance constituting the redox pair include halogens such as iodine, bromine, and chlorine, halides such as dimethylpropylimidazolium iodide, tetrapropylammonium iodide, and lithium iodide. Can be mentioned. As an additive for efficiently transferring electrons, for example, 4-tert-butylpyridine is usually used.

  The constituent material of the spacer S is not particularly limited, and for example, silica beads or the like can be used.

  Further, as a sealing material used for integrating the photoelectrode 10, the counter electrode CE1 and the spacer S for the purpose of sealing the electrolyte E, it can be sealed so that the components of the electrolyte E do not leak to the outside as much as possible. Although there is no particular limitation, for example, an epoxy resin, a silicone resin, an ethylene / methacrylic acid copolymer, a thermoplastic resin made of surface-treated polyethylene, or the like can be used.

  Next, an example of a method for manufacturing the dye-sensitized solar cell 20 shown in FIG. 2 will be described.

When manufacturing the transparent electrodes 1, it can form a transparent conductive film 3 of fluorine-doped SnO ₂ or the like as described above on a substrate 4 such as a glass substrate using known thin film manufacturing technique such as spray coating . For example, in addition to this, it can be formed using a known thin film manufacturing technique such as a vacuum deposition method, a sputtering method, a CVD method, and a sol-gel method.

  Examples of a method for forming the semiconductor electrode 2 on the transparent conductive film 3 of the transparent electrode 1 include the following methods. That is, first, a dispersion liquid in which oxide semiconductor particles having a predetermined size (for example, a particle diameter of about 10 to 30 nm) is dispersed is prepared. The solvent of this dispersion liquid is not particularly limited as long as it can disperse oxide semiconductor particles such as water, an organic solvent, or a mixed solvent of both. Moreover, you may add surfactant and a viscosity modifier to a dispersion liquid as needed.

  Next, the dispersion is applied onto the transparent conductive film 3 of the transparent electrode 1 and then dried. As a coating method at this time, a bar coater method, a printing method, or the like can be used. Then, after drying, the semiconductor electrode 2 (porous semiconductor film) is formed by heating and firing in air, inert gas or nitrogen.

  Next, a sensitizing dye is contained in the semiconductor electrode 2 by a known technique such as an adhesion method. The sensitizing dye is contained by adhering to the semiconductor electrode 2 (chemical adsorption, physical adsorption or deposition). As this adhesion method, for example, a method of immersing the semiconductor electrode 2 in a solution containing a dye can be used. At this time, adsorption and deposition of the sensitizing dye can be promoted by heating and refluxing the solution. At this time, a metal such as silver or a metal oxide such as alumina may be contained in the semiconductor electrode 2 in addition to the pigment, if necessary.

  The surface oxidation treatment for removing impurities that inhibit the photoelectric conversion reaction contained in the semiconductor electrode 2 may be appropriately performed by a known method every time each layer is formed or when all the layers are formed. .

Other methods for forming the semiconductor electrode 2 on the transparent conductive film 3 of the transparent electrode 1 include the following methods. That is, a method of depositing a semiconductor such as TiO ₂ in a film shape on the transparent conductive film 3 of the transparent electrode 1 may be used. As a method for depositing a semiconductor on the transparent conductive film 3, a known thin film manufacturing technique can be used. For example, a physical vapor deposition method such as electron beam vapor deposition, resistance heating vapor deposition, sputter vapor deposition, or cluster ion beam vapor deposition may be used. Metal or the like is evaporated in a reactive gas such as oxygen, and the reaction product is converted into the transparent conductive film 3. A reactive vapor deposition method may be used. Furthermore, chemical vapor deposition such as CVD can be used by controlling the flow of the reaction gas.

  The manufacturing method of the counter electrode CE1 is not particularly limited, and can be formed by the following method, for example. First, the transparent conductive film 7 is formed on the substrate 6. This can be formed by the same method as the transparent electrode 1 provided in the photoelectrode 10. Next, the carbon electrode 8 is formed on the transparent conductive film 7 by the following method, for example.

  That is, carbon black particles, particles made of columnar conductive carbon material, conductive oxide particles having a lower electrical resistivity than anatase-type titanium oxide particles, an organic solvent such as acetylacetone, and ion-exchanged water Then, a slurry containing a surfactant (or a carbon paste obtained by adding a thickener to the slurry) is prepared and applied to one surface of a flat substrate 6 and dried. Then, after drying, the counter electrode CE1 in which the transparent conductive film 7 and the carbon electrode 8 are sequentially formed on one surface of the substrate 6 is completed by performing a sintering process as necessary. The thickness of the carbon electrode 8 can be adjusted by repeating a series of operations of applying the slurry (or paste), drying and sintering.

  After the photoelectrode 10 and the counter electrode CE1 are manufactured in this manner, the photoelectrode 10 and the counter electrode CE are assembled so as to face each other with a spacer S as shown in FIG. At this time, the space formed between the photoelectrode 10 and the counter electrode CE is filled with the electrolyte E by the spacer S, and the dye-sensitized solar cell 20 is completed.

[Second Embodiment]
FIG. 3 is a schematic cross-sectional view showing a second embodiment of the dye-sensitized solar cell of the present invention. Hereinafter, the dye-sensitized solar cell 30 illustrated in FIG. 3 will be described. In addition, the same code | symbol is attached | subjected about the element same as the element demonstrated regarding the dye-sensitized solar cell 20 shown in the above-mentioned FIG. 2, and the overlapping description is abbreviate | omitted. Note that the dye-sensitized solar cell 30 illustrated in FIG. 3 includes a preferred embodiment of the carbon electrode of the present invention as the counter electrode CE2.

  A dye-sensitized solar cell 30 shown in FIG. 3 uses the photoelectrode 10 shown in FIG. 2 and a counter electrode CE2 having the same configuration as the counter electrode CE1 shown in FIG. In the dye-sensitized solar cell 20 shown in FIG. 2, the dye shown in FIG. 3 is compared with the case where the space formed between the photoelectrode 10 and the counter electrode CE1 is filled with the electrolyte E by the spacer S. In the sensitized solar cell 30, the porous body layer PS is disposed between the photoelectrode 10 and the counter electrode CE2. And the board | substrate 6 is arrange | positioned at the surface on the opposite side to the porous body layer PS of counter electrode CE2.

  The porous layer PS has a structure having a large number of pores, and an electrolyte similar to that used in the dye-sensitized solar cell 20 shown in FIG. E (liquid or gel electrolyte) is filled and held.

  The porous body layer PS is not particularly limited as long as it is capable of holding the electrolyte E and does not have electron conductivity. For example, you may use the porous body formed with the rutile type titanium oxide particle. Examples of constituent materials other than rutile type titanium oxide include zirconia, alumina, and silica. Further, the porous layer PS also has a function as a light reflecting layer that reflects light transmitted through the photoelectrode 10 and irradiates the reflected light into the photoelectrode 10 again. Thereby, the utilization efficiency of the light in the photoelectrode 10 can be improved.

  The electrolyte E is also held in the semiconductor electrode 2 and the porous carbon electrode 8 of the counter electrode CE2. The electrolyte leaks from the side surfaces of the semiconductor electrode 2, the porous body layer PS, and the counter electrode CE2 to the outside of the semiconductor electrode 2, the porous body layer PS, and the counter electrode CE2 of the dye-sensitized solar cell 30 shown in FIG. In order to prevent this, it is covered with a sealing material 5.

  Moreover, as the sealing material 5, for example, a thermoplastic resin film such as polyethylene or an epoxy adhesive can be used.

  Furthermore, the counter electrode CE2 has the same configuration as the counter electrode CE1 of the dye-sensitized solar cell 20 shown in FIG. The transparent conductive film 7 and the substrate 6 arranged on the counter electrode CE2 side can be the same as the transparent conductive film 3 and the transparent substrate 4 used for the transparent electrode 1 of the photoelectrode 10. In FIG. 3, the counter electrode CE <b> 2 may have a configuration excluding the transparent conductive film 7, i.e., a configuration including a flat substrate 6 and a carbon electrode 8 formed on one surface of the substrate 6. Further, the counter electrode CE2 may be configured by only the carbon electrode 8 itself when sufficient mechanical strength is obtained. In FIG. 3, the counter electrode CE <b> 2 is formed, for example, on a configuration in which a metal film such as titanium or nickel is disposed instead of the transparent conductive film 7, that is, on a flat substrate 6 and one surface of the substrate 6. It is also possible to employ a configuration comprising a metal film and a carbon electrode 8 formed on the metal film.

  Next, an example of a method for manufacturing the dye-sensitized solar cell 30 shown in FIG. 3 will be described. First, the photoelectrode 10 is produced in the same manner as the dye-sensitized solar cell 20 shown in FIG. Next, the porous layer PS is formed on the surface F22 of the semiconductor electrode 2 of the photoelectrode 10 by the same procedure as that for producing the semiconductor electrode 2 of the photoelectrode 10. For example, a dispersion (slurry) containing a constituent material of the porous layer PS such as rutile type titanium oxide may be prepared, and this may be applied to the surface F22 of the semiconductor electrode 2 and dried.

  Further, the counter electrode CE2 may be formed by the same method as that of the counter electrode CE1 described above. Further, it may be formed by preparing a slurry (or carbon paste) composed of the same composition components as in the case of the counter electrode CE1 described above, and applying the slurry on the surface of the porous layer PS and drying it. In this case, the substrate 6 is formed on the surface of the counter electrode CE2 opposite to the porous material layer PS, and the side surfaces of the semiconductor electrode 2, the porous material layer PS, and the counter electrode CE2 are covered with the sealing material 5 to form the dye. The sensitized solar cell 30 is completed.

[Third Embodiment]
FIG. 4 is a schematic cross-sectional view showing a third embodiment of the dye-sensitized solar cell of the present invention. Hereinafter, the dye-sensitized solar cell 40 shown in FIG. 4 will be described. In addition, the same code | symbol is attached | subjected about the element same as the element demonstrated regarding the dye-sensitized solar cell 20 shown in the above-mentioned FIG. 2, or the dye-sensitized solar cell 30 shown in FIG. Omitted. Note that the dye-sensitized solar cell 40 shown in FIG. 4 includes a preferred embodiment of the carbon electrode of the present invention as a counter electrode CE3.

  The dye-sensitized solar cell 40 shown in FIG. 4 has the same configuration as the dye-sensitized solar cell 30 shown in FIG. 2 except for the shape of the porous layer PS and the shape of the counter electrode CE3 shown below. . That is, in the case of the dye-sensitized solar cell 40 shown in FIG. 4, in addition to the portion where the porous layer PS covers the back surface F22 of the semiconductor electrode 2, it has a bowl-shaped edge portion that tightly covers the side surface of the semiconductor electrode 2. is doing. The flange-shaped edge portion extends in a direction substantially parallel to the normal direction of the light receiving surface F 1 of the transparent electrode 1 of the photoelectrode 10, and the tip thereof is connected to the transparent electrode 1.

  The connecting portion between the transparent electrode 1 and the porous layer PS will be described in more detail. In this connecting portion, the transparent conductive film 3 portion of the transparent electrode 1 is completely scraped off by a technique such as laser scribing, for example. A groove 9 having a depth at which the surface of the transparent substrate 4 appears is formed. And the edge part formed in the groove | channel shape of the porous body layer PS in the part of this groove | channel 9 is inserted.

  The counter electrode CE3 includes a carbon electrode 8 disposed adjacent to the porous body layer PS, and a substrate 6 disposed adjacent to the surface of the carbon electrode 8 opposite to the porous body layer PS. Yes. The counter electrode CE3 is also formed with a bowl-shaped edge portion for closely covering and covering the bowl-shaped edge portion of the porous body layer PS. The saddle-shaped edge portion of the counter electrode CE3 also extends in a direction substantially parallel to the normal direction of the light receiving surface F1 of the transparent electrode 1 of the photoelectrode 10, and the tip thereof is in close contact with the surface of the transparent conductive film 3 of the transparent electrode 1. To be connected.

  Further, the portion of the side surface of the semiconductor electrode 2 that is not covered with the bowl-shaped edge portion of the porous body layer PS and the side surface of the porous body layer PS that is not covered with the bowl-shaped edge portion of the counter electrode CE3. The portion is sealed by disposing the same sealing material 5 as that used in the dye-sensitized solar cell 30 shown in FIG. Further, the same sealing material 5 as that used in the dye-sensitized solar cell 30 shown in FIG. 2 is disposed so as to be in close contact with the outer surface of the bowl-shaped edge portion of the counter electrode CE3. .

  By disposing the substrate 6 and the sealing material 5, it is possible to sufficiently prevent the electrolyte contained in each of the semiconductor electrode 2 and the porous layer PS from escaping to the outside of the battery 40. If necessary, the sealing material 5 may be disposed in close contact between the substrate 6 and the carbon electrode 8. Thereby, the dispersion | distribution to the battery 40 exterior of the electrolyte contained in counter electrode CE3 can be prevented more fully.

  As described above, the dye-sensitized solar cell 40 has a configuration in which the porous layer PS and the counter electrode CE3 are integrated with the transparent electrode 1 of the photoelectrode 10, respectively. And the electrical contact with the photoelectrode 10 and counter electrode CE3 is prevented by the bowl-shaped edge part of porous body layer PS. If the electrical contact between the photoelectrode 10 and the counter electrode CE3 (electron movement between the photoelectrode 10 and the counter electrode CE3) is sufficiently prevented, the saddle-like shape of the porous body layer PS in FIG. A configuration in which the side surface of the semiconductor electrode 2 and the inner side surface of the bowl-shaped edge portion of the counter electrode CE3 are apparently in contact with each other is not provided. In this case, the constituent material of the semiconductor electrode 2 is inserted into the groove 9.

  In the dye-sensitized solar cell 40, when the photoelectrode 10 is formed, the groove 9 is formed by a known technique such as laser scribing, and when the porous body layer PS and the counter electrode CE3 are formed, respectively, 3 can be formed by the same manufacturing method as that of the dye-sensitized solar cell 30 shown in FIG. 3 except that the raw material slurry (or paste) is applied so as to form the edge portion.

[Fourth Embodiment]
FIG. 5 is a schematic cross-sectional view showing a fourth embodiment of the dye-sensitized solar cell of the present invention. Hereinafter, the dye-sensitized solar cell 50 shown in FIG. 5 will be described. 2 are the same as those described for the dye-sensitized solar cell 20 shown in FIG. 2, the dye-sensitized solar cell 30 shown in FIG. 3, or the dye-sensitized solar cell 40 shown in FIG. Are denoted by the same reference numerals, and redundant description is omitted. Note that the dye-sensitized solar cell 50 illustrated in FIG. 5 includes a preferred embodiment of the carbon electrode of the present invention as the counter electrode CE4.

  The dye-sensitized solar cell 50 shown in FIG. 5 has a module form in which a plurality of batteries are provided. The dye-sensitized solar cell 50 shown in FIG. 5 is an example in which a plurality of the dye-sensitized solar cells 30 shown in FIG. 3 or the dye-sensitized solar cells 40 shown in FIG. Show.

  Compared to the dye-sensitized solar cell 30 shown in FIG. 3, the dye-sensitized solar cell 50 shown in FIG. 5 is different from the seal material 5 provided between the single-cell photoelectrodes 10 of adjacent solar cells. A groove 9 is formed between the photoelectrode 10 of a single cell (hereinafter referred to as a single cell A).

  The groove 9 is formed by scraping the semiconductor electrode 2 of the single cell A by a technique such as laser scribing. A portion of the groove 9 in the vicinity of the sealing material 5 reaches the depth at which the layer of the transparent conductive film 3 of the transparent electrode 1 appears by completely removing the portion of the semiconductor electrode 2. Further, in the vicinity of the semiconductor electrode 2 of the single cell A in the groove 9, the portion of the semiconductor electrode 2 and the portion of the transparent conductive film 3 are completely removed, and the layer of the transparent substrate 4 of the transparent electrode 1 appears. It has reached the depth.

  And in the vicinity of the sealing material 5 in the groove 9, the transparent conductive film 3 of the adjacent photoelectrode 10 and the portions of the semiconductor electrode 2 on the transparent conductive film 3 are not in electrical contact with each other. Between these parts, the edge part formed in the shape of a bowl of the porous layer PS of the single cell A is inserted so as to contact the transparent substrate 4 of the transparent electrode 1.

  Further, in the vicinity of the semiconductor electrode 2 of the single cell A in the groove, that is, in the portion between the porous layer PS of the single cell A and the sealing material 5, the counter electrode CE 4 of the single cell A has a bowl shape. The formed edge portion is inserted so as to contact the transparent conductive film 3 of the transparent electrode 1 of the other unit cell A. This dye-sensitized solar cell 50 can be formed by the same manufacturing method as the dye-sensitized solar cell 40 shown in FIG.

[Fifth Embodiment]
FIG. 6 is a schematic cross-sectional view showing a fifth embodiment of the dye-sensitized solar cell of the present invention. Hereinafter, the dye-sensitized solar cell 20A illustrated in FIG. 6 will be described. In addition, the same code | symbol is attached | subjected about the element same as the element demonstrated regarding the dye-sensitized solar cell 20 shown in FIG. 2, and the overlapping description is abbreviate | omitted.

  The dye-sensitized solar cell 20A shown in FIG. 6 has the same configuration as the dye-sensitized solar cell 20 shown in FIG. 2 except that the electrode described below is provided as the counter electrode CE5. That is, the dye-sensitized solar cell 20A shown in FIG. 6 includes a preferred embodiment of the electrode of the present invention as the counter electrode CE5.

  The counter electrode CE5 has the same configuration as the counter electrode CE1 shown in FIG. 2 except that a binder layer 81 described later is disposed between the carbon electrode 8 and the transparent conductive film 7.

  In FIG. 6, the counter electrode CE <b> 5 may be configured without the transparent conductive film 7. That is, the binder layer 81 may be formed on one surface of the flat substrate 6. Alternatively, the constituent material of the substrate 6 may be formed from the constituent material of the transparent conductive film 7 (transparent conductive material), and the binder layer 81 may be formed on one surface of the substrate 6. In FIG. 6, the counter electrode CE <b> 5 is formed, for example, on a configuration in which a metal film such as titanium or nickel is disposed instead of the transparent conductive film 7, that is, on a flat substrate 6 and one surface of the substrate 6. It is also possible to employ a configuration comprising a metal film and a carbon electrode 8 formed on the metal film.

  The binder layer 81 has a structure in which 1) carbon black particles, graphite particles, and anatase-type titanium oxide particles are used as constituent materials, or 2) carbon black particles and graphite particles. And a porous layer having any one of the structures formed using conductive oxide particles having a lower electrical resistivity than anatase-type titanium oxide particles as constituent materials. Note that the conductive oxide particles having a lower electrical resistivity than the anatase type titanium oxide particles have a lower electrical resistivity than the anatase type titanium oxide particles that can be contained in the carbon electrode 8 shown in FIG. Oxide particles can be used.

  This binder layer 81 is a porous layer similar to the carbon electrode 8, and in any of the above-described configurations 1) and 2), the electrolyte E (liquid or gel) is present in the pores. Electrolyte) is retained. Moreover, this porous carbon electrode 8 has the average particle diameter of 1-20 micrometers in the particle | grains which consist of any one of said 1) and 2) regardless of the structure.

  By adopting a configuration in which the binder layer 81 is disposed, the durability of the counter electrode CE5 and the dye-sensitized solar cell 20A can be further improved as compared with the counter electrode CE1 and the dye-sensitized solar cell 20. The above-mentioned effect (further improvement in durability) is obtained when the binder layer 81 containing particles made of graphite is more excellent in binding to the transparent conductive film 7 than the carbon electrode 8. The present inventors consider that.

[Sixth Embodiment]
FIG. 7 is a schematic cross-sectional view showing a sixth embodiment of the dye-sensitized solar cell of the present invention. Hereinafter, the dye-sensitized solar cell 30A illustrated in FIG. 7 will be described. In addition, the same code | symbol is attached | subjected about the element same as the element demonstrated regarding the dye-sensitized solar cell 30 shown in FIG. 3, and the overlapping description is abbreviate | omitted.

  The dye-sensitized solar cell 30A shown in FIG. 7 has the same configuration as the dye-sensitized solar cell 30 shown in FIG. 3 except that the electrode described below is provided as the counter electrode CE6. That is, the dye-sensitized solar cell 30A shown in FIG. 7 includes a preferred embodiment of the electrode of the present invention as the counter electrode CE6.

  The counter electrode CE6 is an electrode having the same configuration as the counter electrode CE5 shown in FIG. Note that the counter electrode CE6 shown in FIG. 7 may also have a configuration in which the transparent conductive film 7 is removed in the same manner as the counter electrode CE5 shown in FIG. That is, the binder layer 81 may be formed on one surface of the flat substrate 6. Alternatively, the constituent material of the substrate 6 may be formed from the constituent material of the transparent conductive film 7 (transparent conductive material), and the binder layer 81 may be formed on one surface of the substrate 6. In FIG. 7, the counter electrode CE <b> 6 is formed, for example, on a configuration in which a metal film such as titanium or nickel is disposed instead of the transparent conductive film 7, that is, on a flat substrate 6 and one surface of the substrate 6. It is also possible to employ a configuration comprising a metal film and a carbon electrode 8 formed on the metal film.

  By adopting a configuration in which the binder layer 81 is disposed, the durability of the counter electrode CE6 and the dye-sensitized solar cell 30A can be further improved as compared with the counter electrode CE2 and the dye-sensitized solar cell 30. The above-mentioned effect (further improvement in durability) is obtained when the binder layer 81 containing particles made of graphite is more excellent in binding to the transparent conductive film 7 than the carbon electrode 8. The present inventors consider that.

[Seventh Embodiment]
FIG. 8 is a schematic cross-sectional view showing a seventh embodiment of the dye-sensitized solar cell of the present invention. Hereinafter, the dye-sensitized solar cell 40A illustrated in FIG. 8 will be described. In addition, the same code | symbol is attached | subjected about the element same as the element demonstrated regarding the dye-sensitized solar cell 40 shown in FIG. 4, and the overlapping description is abbreviate | omitted.

  The dye-sensitized solar cell 40A shown in FIG. 8 is the same as the dye-sensitized solar cell 40 shown in FIG. 4 except that it includes a binder layer 82 (second binder layer) described later. It has the composition of.

  That is, the dye-sensitized solar cell 40A shown in FIG. 8 has a dye except that a binder layer 82 (second binder layer) described later is disposed between the porous body layer PS and the carbon electrode 8. The sensitizing solar cell 40 has the same configuration. Further, the counter electrode CE7 has the same configuration as the counter electrode CE3 shown in FIG. 4 except that it has a film-like carbon electrode 8.

  The binder layer 82 is composed of 1) carbon black particles, graphite particles, and anatase-type titanium oxide particles, or 2) carbon black particles and graphite particles. And a porous layer having any one of the structures formed using conductive oxide particles having a lower electrical resistivity than anatase-type titanium oxide particles as constituent materials. Note that the conductive oxide particles having a lower electrical resistivity than the anatase type titanium oxide particles have a lower electrical resistivity than the anatase type titanium oxide particles that can be contained in the carbon electrode 8 shown in FIG. Oxide particles can be used.

  This binder layer 82 is a porous layer similar to the carbon electrode 8, and in any of the above-described configurations 1) and 2), the electrolyte E (liquid or gel) is present in the pores. Electrolyte) is retained. Moreover, this porous carbon electrode 8 has the average particle diameter of 1-20 micrometers in the particle | grains which consist of any one of said 1) and 2) regardless of the structure.

  By adopting a configuration in which the binder layer 82 is disposed, the durability of the counter electrode CE7 and the dye-sensitized solar cell 40A can be further improved as compared with the counter electrode CE3 and the dye-sensitized solar cell 40. In the case of the dye-sensitized solar cell 40A, the binder layer 82 containing particles made of graphite is more excellent in binding property to the porous layer PS than the carbon electrode 8, and the above-described effect (durability) The present inventors consider that this is a factor that has been obtained.

  Moreover, the binder layer 82 has a collar part formed along the collar part of the porous layer PS. The edge portion (tip portion) of the flange portion of the binder layer 82 is in contact with the transparent conductive film 3 of the photoelectrode 1 in an integrated state, but the binder layer 82 contains particles made of graphite. Since this is superior in binding property to the transparent conductive film 3 than the carbon electrode 8, the counter electrode CE 7 and the dye-sensitized solar cell 40 A are also compared with the counter electrode CE 3 and the dye-sensitized solar cell 40 from this viewpoint. The present inventors consider that the durability of the toner is further improved.

[Eighth Embodiment]
FIG. 9 is a schematic cross-sectional view showing an eighth embodiment of the dye-sensitized solar cell of the present invention. Hereinafter, the dye-sensitized solar cell 50A illustrated in FIG. 9 will be described. In addition, the same code | symbol is attached | subjected about the element same as the element demonstrated regarding the dye-sensitized solar cell 50 shown in FIG. 5, and the overlapping description is abbreviate | omitted.

  The dye-sensitized solar cell 50A shown in FIG. 9 is the same as the dye-sensitized solar cell 50 shown in FIG. 5 except that it includes a binder layer 82 (second binder layer) described later. It has the composition of.

  That is, the dye-sensitized solar cell 50A shown in FIG. 9 is different from the dye layer except that a binder layer 82 (second binder layer) described later is disposed between the porous body layer PS and the carbon electrode 8. The sensitizing solar cell 40 has the same configuration. Further, the counter electrode CE8 has the same configuration as the counter electrode CE4 shown in FIG. 5 except that the film-like carbon electrode 8 is included.

  The binder layer 82 is composed of 1) carbon black particles, graphite particles, and anatase-type titanium oxide particles, or 2) carbon black particles and graphite particles. And a porous layer having any one of the structures formed using conductive oxide particles having a lower electrical resistivity than anatase-type titanium oxide particles as constituent materials. Note that the conductive oxide particles having a lower electrical resistivity than the anatase type titanium oxide particles have a lower electrical resistivity than the anatase type titanium oxide particles that can be contained in the carbon electrode 8 shown in FIG. Oxide particles can be used.

  This binder layer 82 is a porous layer similar to the carbon electrode 8, and in any of the above-described configurations 1) and 2), the electrolyte E (liquid or gel) is present in the pores. Electrolyte) is retained. Moreover, this porous carbon electrode 8 has the average particle diameter of 1-20 micrometers in the particle | grains which consist of any one of said 1) and 2) regardless of the structure.

  By adopting a configuration in which the binder layer 82 is disposed, the durability of the counter electrode CE8 and the dye-sensitized solar cell 50A can be further improved as compared with the counter electrode CE4 and the dye-sensitized solar cell 50. In the case of this dye-sensitized solar cell 50A, the binder layer 82 containing particles made of graphite is more excellent in binding property to the porous layer PS than the carbon electrode 8, and the above-described effect (durability) The present inventors consider that this is a factor that has been obtained.

  Moreover, the binder layer 82 has a collar part formed along the collar part of the porous layer PS. The edge portion (tip portion) of the flange portion of the binder layer 82 is in contact with the transparent conductive film 3 of the photoelectrode 1 in an integrated state, but the binder layer 82 contains particles made of graphite. Since this has better binding properties to the transparent conductive film 3 than the carbon electrode 8, the counter electrode CE 8 and the dye-sensitized solar cell 50 A are also compared with the counter electrode CE 4 and the dye-sensitized solar cell 50 from this viewpoint. The present inventors consider that the durability of the toner is further improved.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  Hereinafter, the carbon electrode, the electrode, and the dye-sensitized solar cell of the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

Example 1
A photoelectrode having the same configuration as that of the photoelectrode 10 shown in FIG. 4 (however, the semiconductor electrode 2 has a two-layer structure) was prepared by the following procedure, and this photoelectrode was used. A dye-sensitized solar cell (area of the light receiving surface F2 of the semiconductor electrode 2: 1 cm ² ) having the same configuration as the dye-sensitized solar cell 40 shown in FIG. 4 was produced. For each layer of the semiconductor electrode 2 having a two-layer structure, a layer disposed on the side close to the transparent electrode 1 is referred to as “first layer”, and a layer disposed on the side close to the porous body layer PS is referred to as “second layer”. The layer.

  First, commercially available anatase-type titanium oxide particles (average particle size: 25 nm, hereinafter referred to as “P25”) and anatase-type titanium oxide particles (average particle size: 200 nm, hereinafter referred to as “P200”) having a different particle size from this. And the total content of P25 and P200 is 15% by mass, and the mass ratio of P25 and P200 is P25: P200 = 30: 70. 3. An activator (manufactured by Tokyo Chemical Industry Co., Ltd., trade name: “Triton-X”) is added and kneaded to form a slurry for forming a second layer (P25 content; 10.5 mass%, P200 content; 5 mass%, hereinafter referred to as “slurry 1”).

  Next, a slurry for forming a first layer (P1 content; 15 mass%; hereinafter, “slurry 2” is prepared by the same preparation procedure as that of the slurry 1 except that only P25 is used without using P200. Was prepared).

On the other hand, a transparent electrode (thickness: 1.1 mm) in which a fluorine-doped SnO ₂ conductive film (film thickness: 700 nm) was formed on a glass substrate (transparent substrate 4) was prepared. Next, a part of the SnO ₂ conductive film was shaved by laser scribing to expose the surface of the transparent substrate 4 and to form a groove 9 (see FIG. 4) having no filler inside.

Next, the slurry 2 was applied onto the SnO ₂ conductive film using a bar coder, and then dried. In this case, the inside of the groove 9 was also filled with the slurry 2 by application of the slurry 2. Then, it baked for 30 minutes on condition of 450 degreeC in air | atmosphere. In this way, the first layer of the semiconductor electrode 2 was formed on the transparent electrode.

Furthermore, the second layer was formed on the first layer by repeating the same application and firing as described above using the slurry 1. In this way, the semiconductor electrode 2 (light receiving surface area: 1.0 cm ² , layer thickness: 10 μm, first layer thickness: 3 μm, second layer thickness: 7 μm) on the SnO ₂ conductive film. And a photoelectrode 10 in a state containing no sensitizing dye was produced.

  Next, the portion of the semiconductor electrode 2 filling the groove 9 was scraped off by laser scribing, and the surface of the transparent substrate 4 was exposed again to form a groove 9 (see FIG. 4) without any filling material inside.

  Next, a slurry for forming the porous layer PS (hereinafter referred to as “slurry 3”) was prepared by the following procedure. That is, slurry 3 uses commercially available silicon dioxide (average particle size: 40 nm, hereinafter referred to as P1) and commercially available rutile-type titanium oxide (average particle size: 400 nm, hereinafter referred to as P2). Except for the total content of 15% by mass and the mass ratio of P1 and P2 being P1: P2 = 35: 65, the porous layer PS was formed by the same preparation procedure as the slurry 1 described above. Slurry 3 was prepared.

  Next, the porous body layer PS (thickness: 7 μm) was formed by repeating the application and sintering of the slurry 3 on the back surface F22 and the side surface of the photoelectrode so as to be in the state shown in FIG. . In this case, a porous layer PS having a bowl-shaped edge portion was formed in the groove 9 by applying the slurry 3 in the same state as shown in FIG.

  Next, by the laser scribing process, the surface on the side where the carbon electrode 8 is formed in the bowl-shaped edge portion of the porous body layer PS was shaved to adjust the shape of the porous body layer PS.

  Next, the counter electrode CE3 was formed on the porous body layer PS by the following procedure. First, a slurry for forming this counter electrode (hereinafter referred to as “slurry 4”) is made of commercially available carbon black-like particles (average particle diameter: 40 nm), particles made of commercially available gas phase synthetic carbon fibers (diameter: 150 nm, 5 μm) and titania (anatase-type titanium oxide) particles (average particle size: 8 nm), and the mass ratio of carbon black particles, carbon fiber particles, and titanium oxide particles is carbon black particles : Particles made of carbon fiber: Titanium oxide particles = 20: 100: 15

  Next, application and sintering of the slurry 4 are repeated so that the state shown in FIG. 4 is obtained in the same manner as in the formation procedure of the photoelectrode 10, and a bowl-shaped edge portion is provided on the outer surface of the porous body layer PS. A carbon electrode 8 (thickness: 50 μm) was formed. Next, the surface on the side in contact with the sealing material 5 in the bowl-shaped edge portion of the carbon electrode 8 was shaved by laser scribing, and the shape of the carbon electrode 8 was adjusted.

Thereafter, the dye was adsorbed in the semiconductor electrode 2 as follows. First, a ruthenium complex [cis-Di (thiocyanato) -N, N'-bis (2,2'-bipyridyl-4,4'dicarboxylic acid) -ruthenium (II)]] is used as a sensitizing dye, and an ethanol solution thereof is used. (Concentration of sensitizing dye; 3 × 10 ⁻⁴ mol / L) was prepared.

Next, the laminate in which the photoelectrode 1, the porous layer PS, and the carbon electrode 8 were integrated was immersed in this solution, and left for 20 hours under a temperature condition of 80 ° C. As a result, a sensitizing dye was adsorbed to the inside of the semiconductor electrode 2 by about 1.0 × 10 ⁻⁷ mol / cm ² . Next, in order to improve the open circuit voltage Voc, the semiconductor electrode 2 after adsorption of the ruthenium complex is immersed in an acetonitrile solution of 4-tert-butylpyridine for 15 minutes, and then dried in a nitrogen stream maintained at 25 ° C. The electrode 10 was completed.

  Next, a sealing material S (trade name: “Himiran”, ethylene / methacrylic acid random copolymer ionomer film) manufactured by Mitsui DuPont Polychemical Co., Ltd. having a shape matched to the size of the semiconductor electrode is prepared. As shown, the semiconductor electrode 2, the porous body layer PS, and the counter electrode CE3 were disposed on the side exposed to the outside and thermally welded. Next, a glass substrate was placed on the outer surface of the carbon electrode 8 and heat-sealed to form the counter electrode CE3, and a battery casing (unfilled electrolyte) was obtained.

  Next, dimethylpropylimidazolium iodide, lithium iodide, and 4-tert-butylpyridine are dissolved in γ-butyrolactone as a solvent to obtain a liquid electrolyte E (concentration of dimethylpropylimidazolium iodide: 0. 6 mol / L, lithium iodide concentration: 0.1 mol / L, 4-tert-butylpyridine concentration: 0.5 mol / L).

  Next, the electrolyte E is injected into the battery casing from a hole provided in advance in the glass substrate of the counter electrode CE3, and then the hole is closed with a member made of the same material as the sealing material S, and further, the hole is formed in the hole of the counter electrode CE3. The member was thermally welded to seal the hole, thereby completing a dye-sensitized solar cell.

(Example 2)
Example 1 was used except that, when forming the counter electrode CE3, Sb-doped SnO ₂ particles (average particle size: 8 nm) were used instead of titania (anatase-type titanium oxide) particles (average particle size: 8 nm). A dye-sensitized solar cell having the same configuration as that of Example 1 was manufactured according to the same manufacturing procedure and conditions.

(Example 3)
A dye-sensitized solar cell (area of the light receiving surface F2 of the semiconductor electrode 2: 1 cm ² ) having the same configuration as that of the dye-sensitized solar cell 20 shown in FIG.

  First, a photoelectrode 10 having the same configuration as that of Example 1 was manufactured according to the same manufacturing procedure and conditions as those of Example 1. Next, a liquid electrolyte having the same configuration as in Example 1 was prepared by the same manufacturing procedure and conditions as in Example 1.

  Next, a transparent electrode similar to the transparent electrode 1 used for the photoelectrode 10 (a transparent conductive film 7 formed on a substrate 6 (in this case, a transparent substrate)) is prepared, and the transparent conductive film 7 is formed on one side. The same slurry 4 as that prepared in Example 1 was applied, and further drying and sintering were repeated to form a carbon electrode 8 (thickness: 20 μm) on the transparent conductive film 7, as shown in FIG. A counter electrode CE1 having the same configuration as in Example 1 was produced.

  A spacer S (trade name: “HIMILAN”) manufactured by Mitsui DuPont Polychemical Co., Ltd. having a shape matched to the size of the semiconductor electrode 2 is prepared, and the photoelectrode 10 and the counter electrode CE1 are connected to the spacer S as shown in FIG. The dye-sensitized solar cell 20 having the same structure as that shown in FIG. 2 was completed by filling the inside with the same electrolyte as that prepared in Example 1.

(Example 4)
A dye-sensitized solar cell (of the light-receiving surface F2 of the semiconductor electrode 2) having the same configuration as that of the dye-sensitized solar cell 20 shown in FIG. Area: 1 cm ² ) was produced.

  First, a photoelectrode 10 having the same configuration as that of Example 1 was manufactured according to the same manufacturing procedure and conditions as those of Example 1. Next, a liquid electrolyte having the same configuration as in Example 1 was prepared by the same manufacturing procedure and conditions as in Example 1.

  Next, by preparing a substrate 6 similar to the transparent substrate 4 used for the photoelectrode 10, applying the same slurry 4 as that prepared in Example 1 on one side, and further repeating drying and sintering, A carbon electrode 8 (thickness: 20 μm) was formed on the substrate 6 to produce a counter electrode CE1 having a configuration similar to that shown in FIG.

  A spacer S (trade name: “HIMILAN”) manufactured by Mitsui DuPont Polychemical Co., Ltd. having a shape matched to the size of the semiconductor electrode 2 is prepared, and the photoelectrode 10 and the counter electrode CE1 are connected to the spacer S as shown in FIG. The dye-sensitized solar cell 20 having the same configuration (but not having the transparent conductive film 7) as shown in FIG.

(Comparative Example 1)
When the counter electrode CE3 was formed, it was carried out except that commercially available graphite-like particles (average particle size: 5 μm) were used instead of commercially available gas phase synthetic carbon fiber particles (diameter: 150 nm, height 5 μm). A dye-sensitized solar cell having the same configuration as that of Example 1 was manufactured according to the same manufacturing procedure and conditions as those of Example 1.

(Comparative Example 2)
When the counter electrode CE1 was formed, a commercial graphite-like particle (average particle size: 5 μm) was used in place of particles (diameter: 150 nm, height 5 μm) made of a commercially available gas-phase synthetic carbon fiber. A dye-sensitized solar cell having the same configuration as that of Example 3 was manufactured according to the same manufacturing procedure and conditions as in Example 3.

(Comparative Example 3)
When the counter electrode CE1 was formed, a commercial graphite-like particle (average particle size: 5 μm) was used in place of particles (diameter: 150 nm, height 5 μm) made of a commercially available gas-phase synthetic carbon fiber. A dye-sensitized solar cell having the same configuration as that of Example 4 was manufactured according to the same manufacturing procedure and conditions as those of Example 4.

[Battery characteristics evaluation test]
A battery characteristic evaluation test was performed according to the following procedure, and the energy conversion efficiency η (%) of the dye-sensitized solar cells of Examples 1 to 4 and Comparative Examples 1 to 3 was measured. The energy conversion efficiency η (%) of the dye-sensitized solar cell is represented by the following formula (A). Here, in the following formula (A), P ₀ is the incident light intensity [mWcm ⁻² ], V _oc is the open circuit voltage [V], J _sc is the short-circuit current density [mA · cm ⁻² ], and F.F. Shows Filling Factor.
η = 100 × (V _oc × J _sc × F.F.) / P ₀ (A)

The battery characteristic evaluation test uses a solar simulator (trade name; “WXS-85-H type”, manufactured by Wacom), and the irradiation conditions of pseudo-sunlight from a xenon lamp light source through an AM filter (AM1.5), The measurement was performed under two measurement conditions: 10 mW / cm ² (so-called “0.1 Sun” irradiation condition) and 100 mW / cm ² (so-called “1 Sun” irradiation condition).

For each dye-sensitized solar cell, the current-voltage characteristics were measured at room temperature using an IV tester, and the open circuit voltage (Voc / V), short circuit current density (Jsc / mA · cm ⁻² ), and fill factor (FF) was calculated | required and energy conversion efficiency (eta) ₀ [%] was calculated | required from these. The obtained results are shown in Table 1 (0.1 Sun irradiation conditions) and Table 2 (1 Sun irradiation conditions). Note that “Jsc @ 1Sun” shown in Table 1 indicates a value obtained by multiplying Jsc actually obtained under irradiation conditions of 0.1 Sun by 10 times.

  As is clear from the results shown in Tables 1 and 2, the dye-sensitized solar cells of Examples 1 to 4 are excellent in FF and energy conversion in any of the two irradiation conditions. It was confirmed that the efficiency η was exhibited.

(Example 5)
The same production procedure and conditions as in Example 2 except that a gel electrolyte obtained by adding a gelling agent (sorbitol) to the liquid electrolyte E used in Example 1 was used. A dye-sensitized solar cell having a configuration (a dye-sensitized solar cell having the same configuration as that of the dye-sensitized solar cell 40 shown in FIG. 4) was produced.

(Example 6)
A dye-sensitized solar cell having the same configuration as that of the dye-sensitized solar cell 40A shown in FIG. 8 was produced. More specifically, the gel electrolyte obtained by adding a gelling agent (sorbitol) to the liquid electrolyte E used in Example 1, and the carbon layer 8 of the porous layer PS and the counter electrode CE7 It was produced by the same production procedure and conditions as in Example 2 except that a binder layer 82 (see FIG. 8) was formed between the two.

The binder layer 82 (thickness: 20 μm) was prepared on the porous material layer PS using the following slurry (hereinafter referred to as “slurry 5”). A slurry for forming the binder layer 82 (hereinafter referred to as “slurry 5”) is made of commercially available carbon black-like particles (average particle size: 40 nm), particles made of commercially available graphite (average particle size: 5 μm), and , Sb-doped SnO ₂ particles (average particle size: 8 nm), and the mass ratio of carbon black particles, carbon fiber particles, and Sb-doped SnO ₂ particles is carbon black particles: graphite particles: Sb dope It was prepared by the same preparation procedure as that of the slurry 1 except that SnO ₂ particles = 20: 100: 15.

The carbon electrode 8 (thickness: 30 μm) was formed on the binder layer 82 using the following slurry (hereinafter referred to as “slurry 6”). Using commercially available carbon black-like particles (average particle size: 40 nm), commercially available gas phase synthetic carbon fiber particles (diameter: 150 μm), and Sb-doped SnO ₂ particles (average particle size: 8 nm), carbon black Slurry 1 except that the mass ratio of the particles, the carbon fiber particles, and the Sb-doped SnO ₂ particles is such that the carbon black-like particles: carbon fiber particles: Sb-doped SnO ₂ particles = 20: 100: 15 The same preparation procedure was used.

  A dye-sensitized solar cell was produced by the same production procedure and conditions as in Example 2 except that the laser scribe process was performed using the slurry 5 and the slurry 6 described above.

(Comparative Example 4)
The gel electrolyte obtained by adding a gelling agent (sorbitol) to the liquid electrolyte E used in Comparative Example 1 and the titania (anatase-type titanium oxide) particles (average) when forming the counter electrode Except for using Sb-doped SnO ₂ particles (average particle size: 8 nm) instead of particle size: 8 nm), a dye increase having the same configuration as that of Comparative Example 1 was performed by the same production procedure and conditions as Comparative Example 1. A sensitive solar cell was produced.

(Example 7)
The gel electrolyte obtained by adding a gelling agent (sorbitol) to the liquid electrolyte E used in Example 3 and the titania (anatase-type titanium oxide) particles (average) when forming the counter electrode Except for using Sb-doped SnO ₂ particles (average particle size: 8 nm) instead of particle size: 8 nm, a dye increase having the same configuration as that of Example 3 was performed in the same manner as in Example 3. A sensitive solar cell (a dye-sensitized solar cell having the same configuration as the dye-sensitized solar cell 20 shown in FIG. 2) was produced.

(Example 8)
A dye-sensitized solar cell having the same configuration as that of the dye-sensitized solar cell 20A shown in FIG. 6 was produced. More specifically, a gel electrolyte obtained by adding a gelling agent (sorbitol) to the liquid electrolyte E used in Example 1, and between the carbon electrode 8 and the transparent conductive film 7 are used. The binder layer 81 (see FIG. 6) was formed, and when forming the carbon electrode 8, Sb-doped SnO ₂ particles (average) instead of titania (anatase-type titanium oxide) particles (average particle size: 8 nm) It was produced by the same production procedure and conditions as in Example 3 except that the particle size was 8 nm.

  The binder layer 81 (thickness: 10 μm) was formed on the transparent conductive film 7 using the slurry 5 described above. The carbon electrode 8 (thickness: 10 μm) was formed on the binder layer 81 using the slurry 6 described above. A dye-sensitized solar cell was produced by the same production procedure and conditions as in Example 3 except that the laser scribe process was performed using the slurry 5 and the slurry 6 described above.

(Comparative Example 5)
The gel electrolyte obtained by adding a gelling agent (sorbitol) to the liquid electrolyte E used in Comparative Example 2 and the titania (anatase-type titanium oxide) particles (average) when forming the counter electrode Except for using Sb-doped SnO ₂ particles (average particle size: 8 nm) instead of particle size: 8 nm), the dye sensitization having the same configuration as that of Comparative Example 2 was performed in the same manner as in Comparative Example 2. A sensitive solar cell was produced.

Example 9
The gel electrolyte obtained by adding the gelling agent (sorbitol) to the liquid electrolyte E used in Example 4 and the titania (anatase-type titanium oxide) particles (average) when forming the counter electrode ₂ except that Sb-doped SnO ₂ particles (average particle diameter: 8 nm) were used instead of the particle diameter: 8 nm), and the dye-sensitized solar cell 20 shown in FIG. A dye-sensitized solar cell having the same configuration (however, a configuration including a counter electrode having a configuration without the transparent conductive film 7 as in Example 4) was produced.

(Example 10)
A dye-sensitized solar cell having the same configuration as that of the dye-sensitized solar cell 20A shown in FIG. 6 (provided that the counter electrode has a configuration without the transparent conductive film 7) was produced. More specifically, the use of a gel electrolyte obtained by adding a gelling agent (sorbitol) to the liquid electrolyte E used in Example 1, and a binder layer between the carbon electrode 8 and the substrate 6 Except that 81 was formed, and Sb-doped SnO ₂ particles (average particle size: 8 nm) were used instead of titania (anatase-type titanium oxide) particles (average particle size: 8 nm) when forming the carbon electrode 8. Was produced by the same production procedure and conditions as in Example 4.

  The binder layer 81 (thickness: 20 μm) was formed on the substrate 6 using the slurry 5 described above. The carbon electrode 8 (thickness: 30 μm) was formed on the binder layer 81 using the slurry 6 described above. A dye-sensitized solar cell was produced by the same production procedure and conditions as in Example 4 except that the laser scribe process was performed using the slurry 5 and the slurry 6 described above.

(Comparative Example 6)
The use of a gel electrolyte obtained by adding a gelling agent (sorbitol) to the liquid electrolyte E used in Comparative Example 3, and, when forming the counter electrode, titania (anatase-type titanium oxide) particles (average Except for using Sb-doped SnO ₂ particles (average particle size: 8 nm) instead of particle size: 8 nm), the same configuration as Comparative Example 3 except that Sb-doped SnO ₂ particles (average particle size: 8 nm) were used. A dye-sensitized solar cell having a configuration having a counter electrode having a configuration without the transparent conductive film 7 as in Example 3 was prepared.

Example 11
A dye-sensitized solar cell having the same configuration as that of Example 2 (a dye-sensitized type having the same configuration as that of the dye-sensitized solar cell 40 shown in FIG. 4) according to the same production procedure and conditions as those of Example 2. Solar cell).

Example 12
A dye having the same structure as that of Example 6 except that the liquid electrolyte E used in Example 1 was used instead of the gel electrolyte used in Example 6 with the same production procedure and conditions as in Example 6. A sensitized solar cell (a dye-sensitized solar cell having the same structure as the dye-sensitized solar cell 40A shown in FIG. 8) was produced.

(Comparative Example 7)
A dye having the same structure as that of Comparative Example 4 except that the liquid electrolyte E used in Comparative Example 1 was used instead of the gel electrolyte used in Comparative Example 4 with the same production procedure and conditions as in Comparative Example 4. A sensitized solar cell was produced.

[Heat cycle test]
Heat cycle tests of the dye-sensitized solar cells of Examples 5 to 12 and Comparative Examples 4 to 7 were performed. The evaluation by the heat cycle test is a low temperature holding process in which the temperature is kept at −40 ° C. for 10 minutes in the dark, and a temperature raising process in which the temperature is raised from −40 ° C. to + 90 ° C. (temperature raising rate: 1.44 ° C. / Min), a high temperature holding process in which the temperature reaches + 90 ° C. and then held at + 90 ° C. for 10 minutes, and a temperature lowering process in which the temperature is lowered from + 90 ° C. to −40 ° C. after the completion of the high temperature holding process (temperature decreasing rate: 1.44) C./min) was performed as one cycle.

  And the energy conversion efficiency (eta) of each dye-sensitized solar cell in 0 cycle, 5 cycles, 10 cycles, 25 cycles, 35 cycles, 50 cycles, 75 cycles, 100 cycles and 125 cycles was measured, and each dye sensitization This was done by comparing the change in the number of heat cycles of η of the solar cell. The results are shown in FIGS.

  As is apparent from the results shown in FIGS. 10 to 13, the dye-sensitized solar cells of Examples 5 to 12 are superior in energy conversion to the dye-sensitized solar cells of Comparative Examples 4 to 7. It was confirmed to show efficiency η and durability. In particular, the dye-sensitized solar cells of Example 6, Example 8, Example 10, and Example 12 having a binder layer have Examples 5, 7, 7, and 9 having a configuration without a binder layer. Compared to the dye-sensitized solar cell of Example 11, it was confirmed that the same or better durability was exhibited. Moreover, it was confirmed that the durability improvement effect provided with this binder layer can be obtained more significantly in the case of a configuration having a gel electrolyte rather than a liquid electrolyte.

  The carbon electrode and electrode obtained by the present invention can be suitably used as a counter electrode of a dye-sensitized solar cell. Moreover, the carbon electrode and electrode obtained by this invention can be utilized also as electrodes other than the counter electrode of a dye-sensitized solar cell. For example, batteries other than dye-sensitized solar cells (for example, air batteries, manganese dry batteries), various processes in the electrolytic industry (for example, electrolytic refining of salt electrolysis, aluminum, calcium, magnesium, alkali metals, etc.), or electrolytic steelmaking It can be used as an anode for electrolytic synthesis. Furthermore, the dye-sensitized solar cell obtained by the present invention can be used as a backup power source for power sources such as portable devices (small electronic devices) and an auxiliary power source for hybrid vehicles.

It is a perspective view which shows typically the internal structure of the counter electrode with which the dye-sensitized solar cell of this invention is equipped. It is a schematic cross section which shows the basic composition of 1st Embodiment of the dye-sensitized solar cell of this invention. It is a schematic cross section which shows the basic composition of 2nd Embodiment of the dye-sensitized solar cell of this invention. It is a schematic cross section which shows the basic composition of 3rd Embodiment of the dye-sensitized solar cell of this invention. It is a schematic cross section which shows the basic composition of 4th Embodiment of the dye-sensitized solar cell of this invention. It is a schematic cross section which shows the basic composition of 5th Embodiment of the dye-sensitized solar cell of this invention. It is a schematic cross section which shows the basic composition of 6th Embodiment of the dye-sensitized solar cell of this invention. It is a schematic cross section which shows the basic composition of 7th Embodiment of the dye-sensitized solar cell of this invention. It is a schematic cross section which shows the basic composition of 8th Embodiment of the dye-sensitized solar cell of this invention. It is a graph which shows the result of the heat cycle test regarding the dye-sensitized solar cell of Example 5, Example 6, and Comparative Example 4. It is a graph which shows the result of the heat cycle test regarding the dye-sensitized solar cell of Example 7, Example 8, and Comparative Example 5. It is a graph which shows the result of the heat cycle test regarding the dye-sensitized solar cell of Example 9, Example 10, and Comparative Example 6. It is a graph which shows the result of the heat cycle test regarding the dye-sensitized solar cell of Example 11, Example 12, and Comparative Example 7. It is a perspective view which shows typically the internal structure of the counter electrode with which the conventional dye-sensitized solar cell is equipped.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transparent electrode, 2 ... Semiconductor electrode, 3 ... Transparent conductive film, 4 ... Transparent substrate, 5 ... Sealing material, 6 ... Substrate, 7 ... Transparent conductive film, 8 ... Carbon electrode, 9 * ..Grooves formed by laser scribing, 10... Photoelectrode, 20, 20A, 30, 30A, 40, 40A, 50, 50A ... Dye-sensitized solar cell, 81... Binder layer, 82. Layer (second binder layer), CE1, CE2, CE3, CE4, CE5, CE6, CE7, CE8 ... counter electrode, E ... electrolyte, F1, F2, F3 ... light receiving surface, F22 ... back surface of semiconductor electrode 2, S ... spacer, PS ... porous layer.

Claims (16)

A porous carbon electrode having pores,
It contains at least carbon black-like particles, particles made of columnar conductive carbon material, and anatase-type titanium oxide particles as constituent materials,
The particles made of the columnar conductive carbon material have a bottom diameter of 50 to 500 nm and a height of 1 to 20 μm,
The mass W1 of the carbon black particles, the mass W2 of the particles made of the columnar conductive carbon material, and the mass W3 of the titanium oxide particles are expressed by the following formulas (1) and (2). Satisfy the conditions shown at the same time,
A carbon electrode characterized by
0.05 ≦ (W1 / W2) ≦ 0.4 (1)
0.05 ≦ {W3 / (W1 + W2)} ≦ 0.4 (2) The carbon electrode according to claim 1, wherein the particles made of the columnar conductive carbon material are particles obtained by cutting carbon fibers. A porous carbon electrode having pores,
Carbon black-like particles, particles made of columnar conductive carbon material, and conductive oxide particles having a lower electrical resistivity than anatase-type titanium oxide particles, at least as constituent materials,
The particles made of the columnar conductive carbon material have a bottom diameter of 50 to 500 nm and a height of 1 to 20 μm,
The contained mass W1 of the carbon black-like particles, the contained mass W2 of the particles made of the columnar conductive carbon material, and the contained mass W4 of the conductive oxide particles are expressed by the following formulas (3) and (4). ) Must be satisfied at the same time,
A carbon electrode characterized by
0.05 ≦ (W1 / W2) ≦ 0.4 (3)
0.05 ≦ {W4 / (W1 + W2)} ≦ 0.4 (4) The carbon electrode according to claim 3, wherein the particles made of the columnar conductive carbon material are particles obtained by cutting carbon fibers. 5. The carbon electrode according to claim 3, wherein an electrical resistivity of the conductive oxide particles is 1 × 10 ⁻² Ω · cm or less. The conductive oxide particles are composed of Sn-doped In ₂ O ₃ , Zn-doped In ₂ O ₃ , Sb-doped SnO ₂ , F-doped SnO ₂ , Al-doped ZnO, Ga-doped ZnO, and In ₄ Sn ₃ O _12. The carbon electrode according to claim 3, wherein the carbon electrode is at least one kind of particles selected from the group. An electrode used as a counter electrode of a dye-sensitized solar cell,
A substrate,
The carbon electrode according to any one of claims 1 to 6,
A binder layer disposed between the substrate and the carbon electrode, for integrating the substrate and the carbon electrode;
At least,
The binder layer contains at least carbon black-like particles, particles made of graphite, and anatase-type titanium oxide particles as constituent materials, and
The particles made of graphite have an average particle diameter of 1 to 20 μm,
An electrode characterized by. An electrode used as a counter electrode of a dye-sensitized solar cell,
A substrate,
The carbon electrode according to any one of claims 1 to 6,
A binder layer disposed between the substrate and the carbon electrode, for integrating the substrate and the carbon electrode;
At least,
The binder layer contains at least carbon black particles, particles made of graphite, and conductive oxide particles having a lower electrical resistivity than anatase-type titanium oxide particles as constituent materials, and
The particles made of graphite have an average particle diameter of 1 to 20 μm,
An electrode characterized by. The electrode according to claim 8, wherein an electrical resistivity of the conductive oxide particles is 1 × 10 ⁻² Ω · cm or less. The conductive oxide particles are composed of Sn-doped In ₂ O ₃ , Zn-doped In ₂ O ₃ , Sb-doped SnO ₂ , F-doped SnO ₂ , Al-doped ZnO, Ga-doped ZnO, and In ₄ Sn ₃ O _12. The electrode according to claim 8 or 9, wherein the electrode is at least one kind of particles selected from the group. A photoelectrode having a semiconductor electrode having a light receiving surface and a transparent electrode disposed adjacent to the light receiving surface; and a counter electrode, wherein the semiconductor electrode and the counter electrode are arranged to face each other with an electrolyte interposed therebetween. A dye-sensitized solar cell,
The counter electrode has a configuration including at least the carbon electrode according to any one of claims 1 to 6,
A dye-sensitized solar cell characterized by 12. A porous layer made of an insulating porous material is further disposed between the semiconductor electrode and the counter electrode, and the electrolyte is contained in the porous layer. 2. A dye-sensitized solar cell according to 1. A second binder layer for further integrating the porous body layer and the counter electrode between the porous body layer and the counter electrode;
The second binder layer contains at least carbon black particles, particles made of graphite, and anatase-type titanium oxide particles as constituent materials, and
The particles made of graphite have an average particle diameter of 1 to 20 μm,
The dye-sensitized solar cell according to claim 12, wherein: A second binder layer for further integrating the porous body layer and the counter electrode between the porous body layer and the counter electrode;
The binder layer contains at least carbon black particles, particles made of graphite, and conductive oxide particles having a lower electrical resistivity than anatase-type titanium oxide particles as constituent materials, and
The particles made of graphite have an average particle diameter of 1 to 20 μm,
The dye-sensitized solar cell according to claim 12, wherein: A photoelectrode having a semiconductor electrode having a light receiving surface and a transparent electrode disposed adjacent to the light receiving surface; and a counter electrode, wherein the semiconductor electrode and the counter electrode are arranged to face each other with an electrolyte interposed therebetween. A dye-sensitized solar cell,
The counter electrode has a configuration including at least the electrode according to any one of claims 7 to 10,
A dye-sensitized solar cell characterized by 16. A porous layer made of an insulating porous material is further disposed between the semiconductor electrode and the counter electrode, and the electrolyte is contained in the porous layer. 2. A dye-sensitized solar cell according to 1.

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