JP2004127849A - Carbon electrode and dye-sensitized solar cell with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dye-sensitized solar cell having an excellent energy conversion efficiency which has a carbon electrode facilitating a rapid electron transfer reaction on the surface of the electrode, and a counter electrode comprising the same carbon electrode. <P>SOLUTION: The carbon electrode CE3 contains at least carbon black-like particles, graphite like particles, and conductive oxide particles having lower electric resistivity than titanium oxide of anatase type, as constituent materials. The dye-sensitized solar cell 40 comprises a light electrode 10 having a semiconductor electrode 2 with a receiving surface F2 and a transparent electrode 1 arranged adjacent to the receiving surface F2, and a counter electrode comprising the carbon electrode CE3. The semiconductor electrode 2 and the counter electrodes CE3 are arranged opposing each other across a porous material layer PS made of an insulating porous material. The porous material layer PS contains electrolyte. <P>COPYRIGHT: (C)2004,JPO

Description

【０１０７】
【表２】

【０１０８】
表１及び表２に示した結果から明らかなように、実施例１及び実施例２の色素増感型太陽電池は、２つの照射条件の何れの場合にも優れたＦ．Ｆ．及びエネルギー変換効率ηを示すことが確認された。
【０１０９】
【発明の効果】
以上説明したように、本発明によれば、電極表面の電子移動反応を速やかに進行させることのできる電子伝導性の高い炭素電極を提供することができる。また、これを対極として備えることにより、電解質中に含有される酸化還元対（例えば、Ｉ_３ ⁻／Ｉ⁻等）の酸化体に電子を反応させて還元体を得る還元反応（例えば、Ｉ_３ ⁻をＩ⁻へ還元する還元反応）を速やかに進行させることが可能となるため、優れたエネルギー変換効率を有する色素増感型太陽電池を構成することができる。
【図面の簡単な説明】
【図１】本発明の色素増感型太陽電池の第１実施形態の基本構成を示す模式断面図である。
【図２】本発明の色素増感型太陽電池の第２実施形態の基本構成を示す模式断面図である。
【図３】本発明の色素増感型太陽電池の第３実施形態の基本構成を示す模式断面図である。
【図４】図２又は図３に示した色素増感型太陽電池を複数併設する場合の一例を示す模式断面図である。
【符号の説明】
１…透明電極、２…半導体電極、３…透明導電膜、４…透明基板、５…シール材、６・・・透明基板、８・・・炭素電極、９・・・レーザスクライブにより形成された溝、１０…光電極，２０，３０，４０，５０…色素増感型太陽電池、ＣＥ１，ＣＥ２，ＣＥ３，ＣＥ４…対極、Ｅ…電解質、Ｆ１，Ｆ２，Ｆ３，…受光面、Ｆ２２…半導体電極２の裏面、Ｓ…スペーサ、ＰＳ…多孔体層。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a carbon electrode and a dye-sensitized solar cell including the same.
[0002]
[Prior art]
2. Description of the Related Art In recent years, various developments of solar cells have been promoted with increasing interest in global warming and energy problems. Among these solar cells, dye-sensitized solar cells have been proposed by Gretzel et al. (Eg, Japanese Patent No. 2664194), and have advantages such as the use of inexpensive materials and the fact that they can be manufactured by a relatively simple process. Is expected to be put to practical use.
[0003]
As a counter electrode of such a dye-sensitized solar cell, for example, a so-called Pt-supported TCO glass substrate (Transparent \ Oxide \ Coated) having a configuration in which a transparent substrate is coated with a transparent conductive film having catalyst particles such as Pt adhered thereto. Glass) and Pt-supported conductive synthetic resin films are known (for example, Japanese Patent No. 2664194). Examples of the TCO glass substrate include a compound (ITO) -coated glass composed of 95% {indium oxide} and {5%} tin oxide, and fluorine-doped SnO.₂(FTO) coated glass etc. are mentioned, and as a conductive synthetic resin film, a conductive PET film etc. are mentioned.
[0004]
However, in addition to the above-mentioned counter electrode, a redox couple (for example, I₃ ⁻/ I⁻Reduction reaction (for example, I)₃ ⁻To I⁻The development of an inexpensive counter electrode that has excellent electrode characteristics that can promptly progress the reduction reaction to a minimum, and that can be easily manufactured, and that is inexpensive, requires the practical use of dye-sensitized solar cells. It is important from the viewpoint of, and various studies have been made so far.
[0005]
For example, as a study as described above, for example, Solar Energy Materials and Solar Cells, 44 (1996) p. 99-117 #, a porous carbon formed using carbon black particles, graphite particles having a plate-like shape, and anatase-type titanium oxide particles (see, for example, FIG. 3 of the above document) as constituent materials. Electrodes have been proposed, and dye-sensitized solar cells using the electrodes as counter electrodes have been proposed.
[0006]
Since the above-mentioned porous carbon electrode can take an electrolyte solution into pores inside the electrode, it is necessary to secure a larger electrode area as compared with the above-described counter electrode composed of a Pt-supported TCO glass substrate. It is advantageous in that it can be easily formed, is lightweight and chemically stable, and can be easily formed into various shapes at low cost.
[0007]
[Patent Document 1]
Japanese Patent No. 2664194 (page 3, FIG. 1)
[Non-patent document 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
[0008]
[Problems to be solved by the invention]
However, the present inventors have compared the dye-sensitized solar cell having the above-described conventional carbon electrode as a counter electrode with respect to the dye-sensitized solar cell having the Pt-supported TCO glass substrate described above as a counter electrode. It has been found that the obtained Filling Factor (hereinafter referred to as “FF”) and energy conversion efficiency η are low and still insufficient.
[0009]
The present invention has been made in view of the above-mentioned problems of the related art, and has a carbon electrode capable of promptly causing an electron transfer reaction on an electrode surface and a counter electrode including the carbon electrode, and has excellent energy conversion efficiency. It is intended to provide a dye-sensitized solar cell having the same.
[0010]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to achieve the above object, and as a result, it has been found that the above-described conventional carbon electrode has an electric conductivity lower than that of the above-described counter electrode made of a Pt-supported TCO glass substrate. I found that it had a great effect.
[0011]
The present inventors have conducted further studies with the aim of improving the electrical conductivity of the electrode, and as a result, when configuring the conventional carbon electrode, instead of the anatase type titanium oxide particles contained as a binder, It has been found that the use of conductive oxide particles having a lower electric resistivity than the above is extremely effective for improving the electric conductivity without losing the advantages described above, and the present invention Reached.
[0012]
That is, the present invention is a porous carbon electrode having pores, carbon black-like particles, graphite-like particles, conductive oxide particles having a lower electrical resistivity than anatase-type titanium oxide particles, Is provided at least as a constituent material.
[0013]
In the present invention, the electric conductivity of the obtained carbon electrode can be improved by using conductive oxide particles having lower electric resistivity than anatase type titanium oxide particles as a constituent material. Therefore, the carbon electrode of the present invention can make the electron transfer reaction proceed more rapidly than the conventional carbon electrode described above. In addition, the carbon electrode of the present invention can easily secure a wide electrode area, is lightweight and chemically stable, and has a low cost, as compared with the above-mentioned conventional electrode comprising a PT-supported TCO glass substrate. Thus, a desired shape can be easily formed.
[0014]
Therefore, when the carbon electrode of the present invention is used as a counter electrode of a dye-sensitized solar cell, a redox couple (for example, I₃ ⁻/ I⁻And the like.₃ ⁻To I⁻(Reduction reaction to reduce to) can be made to proceed promptly, and high energy conversion efficiency can be obtained. In addition, since the carbon electrode of the present invention is light and can be easily formed into a desired shape, a compact and lightweight dye-sensitized solar cell can be easily formed at low cost.
[0015]
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 (eg, air batteries, manganese dry batteries), various processes in the electrolytic industry (eg, salt electrolysis, electrolytic refining of aluminum, calcium, magnesium, alkali metals, etc.), or electrolytic steelmaking, anode for electrolytic synthesis You may use as.
[0016]
Further, the present invention has 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, and the semiconductor electrode and the counter electrode are interposed with an electrolyte. A dye-sensitized solar cell, wherein the counter electrode is the above-described carbon electrode of the present invention.
[0017]
As described above, by using the above-described carbon electrode of the present invention as a counter electrode, a dye-sensitized solar cell having excellent energy conversion efficiency can be easily configured. When the carbon electrode of the present invention is used as a counter electrode of a dye-sensitized solar cell, the carbon electrode itself may be used as a counter electrode, and the carbon electrode of the present invention formed integrally on a substrate is used as a counter electrode. You may use as.
[0018]
Here, in the present invention, “dye” refers to a metal complex dye and an organic dye. The term “electrolyte” refers to an electrolyte solution (hereinafter, referred to as “electrolyte solution” as necessary), a solution obtained by adding a gelling agent to the electrolyte solution to form a gel, and a solid electrolyte.
[0019]
In this specification, the term “carbon black-like particles” refers to carbon black particles (in an amorphous state, in a crystallized state, as well as in an amorphous state and in a crystallized state. Aerogel particles (in an amorphous state, in a crystallized state, and in a state in which a structure in an amorphous state and a structure in a crystallized state are mixed), and the carbon 2 shows a mixture of black particles and the above carbon airgel particles. The shape of the carbon black particles is not particularly limited, and may be, for example, hollow particles.
[0020]
Further, in the present specification, "graphite-like particles" means (i) graphite particles, (ii) swelling between layers of graphite particles, and (iii) a state in which other elements are taken in between layers of graphite particles. And (iv) a mixture obtained by arbitrarily mixing at least two kinds of particles among the above (i) to (iii).
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
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 will be denoted by the same reference characters, without redundant description.
[0022]
[First Embodiment]
FIG. 1 is a schematic sectional view showing a basic configuration of a first embodiment of the dye-sensitized solar cell of the present invention. The dye-sensitized solar cell 20 shown in FIG. 1 includes a preferred embodiment of the carbon electrode of the present invention as a counter electrode CE1.
[0023]
The dye-sensitized solar cell 20 shown in FIG. 1 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 CE1 by a spacer S. Have been. The photoelectrode 10 shown in FIG. 1 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. The semiconductor electrode 2 is in contact with the electrolyte E on the back surface F22 opposite to the light receiving surface F2.
[0024]
In the dye-sensitized solar cell 20, the sensitizing dye adsorbed in the semiconductor electrode 2 is excited by the light transmitted through the transparent electrode 1 and irradiated to the semiconductor electrode 2, and the semiconductor electrode 2 The electrons are injected into. Then, the electrons injected into the semiconductor electrode 2 are collected by the transparent electrode 1 and taken out.
[0025]
The configuration of the transparent electrode 1 is not particularly limited, and a transparent electrode mounted on an ordinary dye-sensitized solar cell can be used. For example, the transparent electrode 1 shown in FIG. 1 has a configuration in which a so-called transparent conductive film 3 is coated on a semiconductor substrate 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.
[0026]
For example, fluorine-doped SnO₂Coated glass, ITO coated glass, ZnO: Al coated glass, antimony-doped tin oxide (SnO₂—Sb), and the like. Further, a transparent electrode in which tin oxide or indium oxide is doped with a cation or anion having a different valence, a metal electrode having a structure capable of transmitting light such as a mesh or a stripe, and provided on a substrate such as a glass substrate may be used. Good.
[0027]
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 a transparent glass substrate, a substrate in which light reflection is prevented by appropriately roughening the surface of the glass substrate, and a substrate that transmits light such as a frosted glass-like translucent glass substrate. 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.
[0028]
The semiconductor electrode 2 shown in FIG. 1 includes 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 an oxide semiconductor, for example, TiO₂, ZnO, SnO₂, Nb₂O₅, In₂O₃, WO₃, ZrO₂, La₂O₃, Ta₂O₅, SrTiO₃, BaTiO₃Etc. can be used. Among these oxide semiconductors, anatase type TiO₂Is preferred.
[0029]
The sensitizing dye contained in the semiconductor electrode 2 is not particularly limited as long as the dye has absorption in a visible light region and / or an infrared light region. More preferably, any material can be used as long as it is excited by light having a wavelength of at least 200 nm to 10 μm and emits electrons. 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.
[0030]
The counter electrode CE1 is connected to a redox couple (for example, I₃ ⁻/ I⁻And the like.₃ ⁻To I⁻(Reduction reaction to reduce to) is rapidly progressed.
[0031]
That is, the counter electrode CE <b> 1 is composed of the flat substrate 6 and the carbon electrode 8 formed on one surface of the substrate 6. The counter electrode CE1 is arranged so that the carbon electrode 8 contacts the electrolyte E. In FIG. 1, the counter electrode CE1 may be configured to include only the carbon electrode 8 itself when sufficient mechanical strength is obtained.
[0032]
The substrate 6 serves as a support for the carbon electrode 8. The configuration of the substrate 6 is not particularly limited. For example, the same configuration as the transparent substrate 4 described above may be used.
[0033]
The carbon electrode 8 is a porous electrode formed of at least carbon black-like particles, graphite-like particles, and conductive oxide particles having a lower electric resistivity than anatase-type titanium oxide particles. An electrolyte E (liquid or gel electrolyte) is held in the pores of the porous carbon electrode 8.
[0034]
Here, from the viewpoint of more reliably obtaining the high electron conductivity of the carbon electrode 8, the content W1 of the carbon black particles, the content W2 of the graphite particles, and the content W3 of the conductive oxide particles are: It is preferable that the conditions represented by the following formulas (1) and (2) are simultaneously satisfied.
[0035]
0.05 ≦ (W1 / W2) ≦ 0.4 (1)
0.05 ≦ {W3 / (W1 + W2)} ≦ 0.4 (2)
[0036]
In the formula (1), if (W1 / W2) is less than 0.05, the area of the electrode is reduced, so that a redox couple (for example, I₃ ⁻/ I⁻And the like.₃ ⁻To I⁻The rate of the reduction reaction (reduction reaction to reduce to) decreases. Further, in the formula (1), when (W1 / W2) exceeds 0.4, the tendency for the electrical conductivity to decrease increases.
[0037]
Further, in the formula (2), when {W3 / (W1 + W2)} is less than 0.05, the mechanical strength of the carbon electrode 8 itself decreases, and a part or all of the carbon electrode 8 is peeled off. The tendency for cracks to occur in the carbon electrode 8 increases. Further, in the equation (2), when {W3 / (W1 + W2)} exceeds 0.4, the tendency of the electron conductivity to decrease is increased.
[0038]
Further, from the viewpoint of more reliably obtaining the high electron conductivity of the carbon electrode 8 as described above, the electric resistivity of the conductive oxide particles is 1 × 10^-2It is preferably Ω · cm or less. The electrical resistivity of the conductive oxide particles is 1 × 10^-2If it exceeds Ω · cm, it tends to be difficult to obtain sufficient electron conductivity.
[0039]
Further, the conductive oxide particles satisfying the above conditions include Sn-doped In.₂O₃, Zn-doped In₂O₃, Sb-doped SnO₂, F-doped SnO₂, Al-doped ZnO, Ga-doped ZnO, and In₄Sn₃O₁₂The particles are preferably at least one kind of particles selected from the group consisting of:
[0040]
In addition, from the viewpoint of more reliably obtaining the high electron conductivity of the carbon electrode 8, Sn-doped In is used.₂O₃It is preferable that the ratio of the number of Sn atoms to the number of In atoms (the number of Sn atoms / the number of In atoms) contained in the compound is 0.01 to 0.25. . Also, Zn-doped In₂O₃It is preferable that the ratio of the number of Zn atoms to the number of In atoms (the number of Zn atoms / the number of In atoms) contained in the compound is 0.01 to 0.25. .
[0041]
Further, Sb-doped SnO₂It is preferable that the ratio of the number of Sb atoms to the number of Sn atoms (the number of Sb atoms / the number of Sn atoms) contained in the compound is 0.05 to 0.55. . Also, F-doped SnO₂The ratio of the number of F atoms to the number of O (oxygen atoms) contained in this compound (the number of F atoms / the number of O atoms) is 0.05 to 0.50. Preferably, there is.
[0042]
Further, as a particle made of Al-doped ZnO, the ratio of the number of Al atoms to the number of Zn atoms contained in this compound (the number of Al atoms / the number of Zn atoms) is 0.01 to 0.25. It is preferable that Further, as the 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
[0043]
In addition, in the counter electrode CE1, which is a porous carbon electrode, for example, catalyst particles such as Pt particles may be dispersed and supported from the viewpoint of promptly proceeding the electrode reaction.
[0044]
Further, 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, and may be, for example, a liquid electrolyte. It may be a gel electrolyte obtained by adding a known gelling agent (a high-molecular or low-molecular gelling agent).
[0045]
The solvent of the liquid electrolyte used for the electrolyte E is not particularly limited as long as it is a compound capable of dissolving a solute component. However, a solvent which is electrochemically inert, has a high relative dielectric constant and a low viscosity (and These are preferably dissolved in a mixed solvent thereof. Examples thereof include, for example, nitrile compounds such as methoxypropionitrile and acetonitrile, lactone compounds such as γ-butyrolactone and valerolactone, and carbonate compounds such as ethylene carbonate and propylene carbonate. And propylene carbonate.
[0046]
As a solute of the liquid electrolyte used for the electrolyte E, a redox couple (I) capable of transferring electrons to and from a dye supported on the semiconductor electrode 2 and the counter electrode CE.₃ ⁻/ I⁻System electrolyte, Br₃ ⁻/ Br⁻Electrolytes, redox electrolytes such as hydroquinone / quinone-based electrolytes), compounds having an action to promote the transfer of electrons, and the like, each of which may be included alone or in combination.
[0047]
More specifically, examples of the substance constituting the redox couple include halogens such as iodine, bromine, and chlorine, dimethylpropylimidazolium iodide, tetrapropylammonium iodide, and halides such as lithium iodide. No. For example, 4-tert-butylpyridine is generally used as an additive for efficiently transferring electrons.
[0048]
The constituent material of the spacer S is not particularly limited, and for example, silica beads or the like can be used.
[0049]
The sealing material used to integrate the photoelectrode 10, the counter electrode CE and the spacer S for the purpose of sealing the electrolyte E can be sealed so that the components of the electrolyte E do not leak to the outside as much as possible. There is no particular limitation, and for example, an epoxy resin, a silicone resin, an ethylene / methacrylic acid copolymer, and a thermoplastic resin made of surface-treated polyethylene can be used.
[0050]
Next, an example of a method for manufacturing the dye-sensitized solar cell 20 shown in FIG. 1 will be described.
[0051]
When the transparent electrode 1 is manufactured, the above-mentioned fluorine-doped SnO is formed on a substrate 4 such as a glass substrate.₂Can be formed by using a known thin film manufacturing technique such as spray coating the transparent conductive film 3. For example, in addition to this, it can be formed by using a known thin film manufacturing technique such as a vacuum deposition method, a sputtering method, a CVD method, and a sol-gel method.
[0052]
As a method of forming the semiconductor electrode 2 on the transparent conductive film 3 of the transparent electrode 1, for example, there is the following method. 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 is not particularly limited as long as it can disperse the oxide semiconductor particles, such as water, an organic solvent, or a mixed solvent of both. Further, a surfactant and a viscosity modifier may be added to the dispersion as needed.
[0053]
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 baking in air, inert gas or nitrogen.
[0054]
Next, a sensitizing dye is contained in the semiconductor electrode 2 by a known technique such as an immersion method. The sensitizing dye is contained by being attached to the semiconductor electrode 2 (chemical adsorption, physical adsorption, deposition, or the like). For this attachment method, for example, a method of immersing the semiconductor electrode 2 in a solution containing a dye can be used. At this time, the adsorption and deposition of the sensitizing dye can be promoted by heating and refluxing the solution. At this time, in addition to the dye, a metal such as silver or a metal oxide such as alumina may be contained in the semiconductor electrode 2 as necessary.
[0055]
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. .
[0056]
Another method for forming the semiconductor electrode 2 on the transparent conductive film 3 of the transparent electrode 1 is as follows. That is, TiO is formed on the transparent conductive film 3 of the transparent electrode 1.₂Alternatively, a method of depositing a semiconductor in the form of a film may be used. As a method of depositing a semiconductor in a film on the transparent conductive film 3, a known thin film manufacturing technique can be used. For example, physical vapor deposition methods such as electron beam vapor deposition, resistance heating vapor deposition, sputter vapor deposition, cluster ion beam vapor deposition, etc. may be used. A reactive vapor deposition method of depositing on top may be used. Further, a chemical vapor deposition method such as CVD can be used by controlling the flow of the reaction gas.
[0057]
The method for manufacturing the counter electrode CE1 is not particularly limited, either. For example, the counter electrode CE1 can be formed by the following method. That is, carbon black-like particles, graphite-like particles, conductive oxide particles having a lower electrical resistivity than anatase-type titanium oxide particles, an organic solvent such as acetylacetone, ion-exchanged water, and a surfactant. The slurry may be formed by preparing a slurry containing the slurry (or a carbon paste obtained by adding a thickener to the slurry), applying the slurry on one surface of the flat substrate 6, and drying the slurry. Then, after drying, a sintering process is performed as necessary to form a carbon electrode 8 on one surface of the substrate 6 to complete the counter electrode CE1. In addition, the thickness of the carbon electrode 8 can be adjusted by repeating a series of operations of application, drying, and sintering of the slurry (or paste).
[0058]
After the photoelectrode 10 and the counter electrode CE1 are manufactured in this manner, the photoelectrode 10 and the counter electrode CE are assembled to face each other via the 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.
[0059]
[Second embodiment]
FIG. 2 is a schematic sectional view showing a second embodiment of the dye-sensitized solar cell of the present invention. Hereinafter, the dye-sensitized solar cell 30 shown in FIG. 2 will be described. The same components as those described with respect to the dye-sensitized solar cell 20 shown in FIG. 1 described above are denoted by the same reference numerals, and redundant description will be omitted. The dye-sensitized solar cell 30 shown in FIG. 2 includes a preferred embodiment of the carbon electrode of the present invention as a counter electrode CE2.
[0060]
The dye-sensitized solar cell 30 shown in FIG. 2 uses the photoelectrode 10 shown in FIG. 1 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. 1, the space formed between the photoelectrode 10 and the counter electrode CE1 is filled with the electrolyte E by the spacer S, as compared with the dye shown in FIG. In the sensitized solar cell 30, the porous layer PS is disposed between the photoelectrode 10 and the counter electrode CE2. The counter electrode CE2 includes a carbon electrode 8 disposed adjacent to the porous layer PS, and a substrate 6 disposed adjacent to the surface of the carbon electrode 8 opposite to the porous layer PS. ing.
[0061]
This 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.
[0062]
The porous body layer PS is not particularly limited as long as it can hold the electrolyte E and has no electron conductivity. For example, a porous body formed of rutile-type titanium oxide particles may be used. In addition, as a constituent material other than the rutile type titanium oxide, zirconia, alumina, silica, and the like can be given. Further, the porous layer PS also has a function as a light reflection layer that reflects light transmitted through the photoelectrode 10 and irradiates the reflected light into the photoelectrode 10 again. Thereby, the light use efficiency of the photoelectrode 10 can be improved.
[0063]
The electrolyte E is also held in the semiconductor electrode 2 and the porous carbon electrode 8 of the counter electrode CE2. Then, on the side surfaces of the semiconductor electrode 2, the porous layer PS, and the counter electrode CE of the dye-sensitized solar cell 30 shown in FIG. 2, the electrolyte E leaks outside from the side surfaces of the semiconductor electrode 2, the porous layer PS, and the counter electrode CE2. In order to prevent this, it is covered with a sealing material 5.
[0064]
Further, as the sealing material 5, for example, a thermoplastic resin film such as polyethylene or an epoxy-based adhesive can be used.
[0065]
Further, the counter electrode CE2 has the same configuration as the counter electrode CE1 of the dye-sensitized solar cell 20 shown in FIG. As the substrate 6 disposed on the counter electrode CE2, the same substrate as the transparent substrate 4 used for the transparent electrode 1 of the photoelectrode 10 can be used. In addition, in FIG. 2, the counter electrode CE2 may be configured to include only the carbon electrode 8 itself when sufficient mechanical strength is obtained.
[0066]
Next, an example of a method for manufacturing the dye-sensitized solar cell 30 shown in FIG. 2 will be described. First, the photoelectrode 10 is manufactured 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 manufacturing the semiconductor electrode 2 of the photoelectrode 10. For example, it may be formed by preparing a dispersion (slurry) containing a constituent material of the porous layer PS such as rutile-type titanium oxide, applying the dispersion on the surface F22 of the semiconductor electrode 2, and drying.
[0067]
Further, the counter electrode CE2 may be formed by the same method as the counter electrode CE1 described above. Alternatively, the slurry may be formed by preparing a slurry (or carbon paste) having the same composition as that of the counter electrode CE1 described above, applying the slurry on the surface of the porous layer PS, and drying. In this case, the substrate 6 is formed on the surface of the counter electrode CE2 on the side opposite to the side of the porous layer PS, and the side surfaces of the semiconductor electrode 2, the porous layer PS and the counter electrode CE2 are covered with the sealing material 5, and The sensitized solar cell 30 is completed.
[0068]
[Third embodiment]
FIG. 3 is a schematic 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. 3 will be described. Note that the same elements as those described with respect to the dye-sensitized solar cell 20 shown in FIG. 1 or the dye-sensitized solar cell 30 shown in FIG. Omitted. The dye-sensitized solar cell shown in FIG. 3 includes a preferred embodiment of the carbon electrode of the present invention as a counter electrode CE3.
[0069]
The dye-sensitized solar cell 40 illustrated in FIG. 3 has the same configuration as the dye-sensitized solar cell 30 illustrated in FIG. 2 except for the shape of the porous layer PS and the shape of the counter electrode CE3 described below. . That is, in the case of the dye-sensitized solar cell 40 illustrated in FIG. 3, in addition to the portion where the porous layer PS covers the back surface F22 of the semiconductor electrode 2, a flange-shaped edge portion that tightly covers the side surface of the semiconductor electrode 2. Have. The brim-shaped edge portion 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 is connected to the transparent electrode 1.
[0070]
The connection between the transparent electrode 1 and the porous layer PS will be described in more detail. At this connection, the portion of the transparent conductive film 3 of the transparent electrode 1 is completely removed by a technique such as laser scribe, for example. A groove 9 having a depth at which the surface of the transparent substrate 4 appears is formed. Then, an edge portion formed in a flange shape of the porous material layer PS is inserted into the groove 9 portion.
[0071]
The counter electrode CE3 includes a carbon electrode 8 disposed adjacent to the porous layer PS, and a substrate 6 disposed adjacent to the surface of the carbon electrode 8 opposite to the porous layer PS. I have. The counter electrode CE3 also has a flange-shaped edge portion for closely covering the flange-shaped edge portion of the porous material layer PS. The flange-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 its tip is in close contact with the surface of the transparent conductive film 3 of the transparent electrode 1. Connected to be.
[0072]
Further, the portion of the side surface of the semiconductor electrode 2 that is not covered with the flange-shaped edge portion of the porous layer PS, and the portion of the side surface of the porous layer PS that is not covered with the flange-shaped edge portion of the counter electrode CE3. The portion is sealed by closely attaching a sealing material 5 similar to 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 arranged so as to be in close contact with the outer surface of the flange-shaped edge portion of the counter electrode CE3. .
[0073]
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 material layer PS from escaping to the outside of the battery 40. If necessary, the sealing material 5 may be disposed between the substrate 6 and the carbon electrode 8 in close contact with each other. Thereby, the escape of the electrolyte contained in the counter electrode CE3 to the outside of the battery 40 can be more sufficiently prevented.
[0074]
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. The flange-shaped edge portion of the porous layer PS prevents electrical contact between the photoelectrode 10 and the counter electrode CE3. In addition, if electrical contact between the photoelectrode 10 and the counter electrode CE3 (electron transfer between the photoelectrode 10 and the counter electrode CE3) is sufficiently prevented, the flange-like shape of the porous layer PS in FIG. , The side surface of the semiconductor electrode 2 may be apparently in contact with the inner side surface of the flange-shaped edge portion of the counter electrode CE3. In this case, the constituent material of the semiconductor electrode 2 is inserted into the groove 9.
[0075]
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 layer PS and the counter electrode CE3 are formed, the above-described flange shape is formed. Can be formed by the same manufacturing method as that of the dye-sensitized solar cell 30 shown in FIG. 2 except that a slurry (or paste) as a raw material is applied so that the edge portion is formed.
[0076]
As described above, the preferred embodiments of the present invention have been described, but the present invention is not limited to the above embodiments.
[0077]
For example, the dye-sensitized solar cell of the present invention may have the form of a module in which a plurality of cells are provided in parallel, such as the dye-sensitized solar cell 50 shown in FIG. The dye-sensitized solar cell 50 illustrated in FIG. 4 is an example in which a plurality of the dye-sensitized solar cells 30 illustrated in FIG. 2 or the dye-sensitized solar cells 40 illustrated in FIG. Is shown.
[0078]
Compared to the dye-sensitized solar cell 30 shown in FIG. 2, the dye-sensitized solar cell 50 shown in FIG. 4 has one side of the sealing material 5 provided between the photoelectrodes 10 of the single cells of the adjacent solar cells. The groove 9 is formed between the photoelectrode 10 of the single cell (hereinafter, referred to as a single cell A).
[0079]
The groove 9 is formed by shaving the semiconductor electrode 2 of the single cell A by a technique such as laser scribing. The portion of the groove 9 near the sealing material 5 has reached the depth at which the layer of the transparent conductive film 3 of the transparent electrode 1 appears by completely removing the semiconductor electrode 2 portion. Further, in the portion of the trench 9 near the semiconductor electrode 2 of the single cell A, 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. To the depth.
[0080]
The transparent conductive film 3 of the adjacent photoelectrode 10 and the portion of the semiconductor electrode 2 on the transparent conductive film 3 are not electrically connected to the portion of the groove in the vicinity of the sealing material 5 so as not to be in electrical contact with each other. Are inserted in such a manner that the brim-shaped edge portion of the porous layer PS of the single cell A is in contact with the transparent substrate 4 of the transparent electrode 1.
[0081]
Further, a portion of the groove near the semiconductor electrode 2 of the single cell A, that is, a portion between the porous layer PS of the single cell A and the sealing material 5 is formed in a flange shape of the counter electrode CE of the single cell A. The formed edge portion is inserted so as to contact the transparent conductive film 3 of the transparent electrode 1 of the other single cell A. The dye-sensitized solar cell 50 can be formed by the same manufacturing method as the dye-sensitized solar cell 40 shown in FIG.
[0082]
【Example】
Hereinafter, the carbon 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.
[0083]
(Example 1)
A photoelectrode having the same configuration as that of the photoelectrode 10 shown in FIG. 3 (however, the semiconductor electrode 2 has a two-layer structure) is manufactured by the following procedure, and further, this photoelectrode is used. The dye-sensitized solar cell having the same configuration as the dye-sensitized solar cell 40 shown in FIG. 3 (the area of the light receiving surface F2 of the semiconductor electrode 2:1cm²) Was prepared. For each layer of the semiconductor electrode 2 having a two-layer structure, a layer disposed on the side closer to the transparent electrode 1 is referred to as a “first layer”, and a layer disposed on a side closer to the porous layer PS is referred to as a “second layer”. Layer. "
[0084]
First, commercially available anatase-type titanium oxide particles (average particle diameter: 25 nm, hereinafter, referred to as “P25”) and anatase-type titanium oxide particles having different particle diameters (average particle diameter: 200 nm, hereinafter, “P200”) Acetylacetone, ion-exchanged water, interface, 6. Add an activator (trade name: "Triton-X", manufactured by Tokyo Chemical Industry Co., Ltd.), knead the mixture, and form a slurry for forming a second layer (P25 content; 7.5% by mass; P200 content; 5% by mass, hereinafter referred to as “slurry 1”).
[0085]
Next, a slurry for forming a first layer (P1 content: 15% by mass, hereinafter referred to as “slurry 2”) was prepared in the same preparation procedure as that for the slurry 1 except that only P25 was used without using P200. ") Was prepared.
[0086]
On the other hand, a glass substrate (transparent conductive glass) is doped with fluorine-doped SnO.₂A transparent electrode (thickness: 1.1 mm) on which a conductive film (thickness: 700 nm) was formed was prepared. And this SnO₂The slurry 2 was applied on the conductive film using a bar coder, and then dried. Then, it baked for 30 minutes under the conditions of 450 degreeC in air | atmosphere. Thus, the first layer of the semiconductor electrode 2 was formed on the transparent electrode.
[0087]
Further, by using the slurry 1 and repeating the same application and baking as described above, a second layer was formed on the first layer. In this way, SnO₂Semiconductor electrode 2 (area of light receiving surface; 1.0 cm) on conductive film², A layer thickness of 10 μm, a layer thickness of the first layer: 3 μm, and a layer thickness of the second layer: 7 μm) to produce a photoelectrode 10 containing no sensitizing dye.
[0088]
Thereafter, the dye was adsorbed on the back surface of the semiconductor electrode as follows. First, a ruthenium complex [cis-Di (thiocyanato) -N, N'-bis (2,2'-bipyridyl-4,4'dicarboxylic acid] -ruthenium (II)] was used as a sensitizing dye, and an ethanol solution thereof was used. (Concentration of sensitizing dye; 3 × 10^-4mol / L).
[0089]
Next, the semiconductor electrode was immersed in this solution, and was left under a temperature condition of 80 ° C. for 20 hours. As a result, about 1.0 × 10^-7mol / cm²Adsorbed. Next, in order to improve the open-circuit voltage Voc, the semiconductor electrode after the adsorption of the ruthenium complex was immersed in an acetonitrile solution of 4-tert-butylpyridine for 15 minutes, and then dried in a nitrogen gas stream maintained at 25 ° C. 10 was completed.
[0090]
Next, as shown in FIG. 3, a predetermined area of the transparent conductive film 3 of the photoelectrode 10 was cut by performing a laser scribing process, a groove 9 was formed, and the surface of the transparent substrate 4 was exposed.
[0091]
Next, a slurry for forming the porous material layer PS (hereinafter, referred to as “slurry 3”) was prepared by the following procedure. That is, the slurry 3 uses commercially available silicon dioxide (average particle diameter: 40 nm, hereinafter, referred to as P1) and commercially available rutile type titanium oxide (average particle diameter: 400 nm, hereinafter, referred to as P2). Except that the total content was 15% by mass and the mass ratio between P1 and P2 was P1: P2 = 35: 65, the same preparation procedure as that for the slurry 1 was used to form the porous material layer PS. Slurry 3 was prepared. Then, application and sintering of the slurry 3 were repeated on the back surface F22 and the side surface of the photoelectrode so that the state shown in FIG. 3 was obtained, thereby forming a porous layer PS having a thickness of 7 μm.
[0092]
Next, a counter electrode CE3 was formed by the following procedure. A slurry for forming the counter electrode (hereinafter, referred to as “slurry 4”) was prepared by using commercially available carbon black particles (average particle size: 40 nm), commercially available graphite particles (average particle size: 5 μm), and Sb-doped particles. SnO₂Particles (average particle size: 8 nm), carbon black-like particles, graphite-like particles, and Sb-doped SnO₂When the mass ratio of the particles is carbon black particles: graphite particles: Sb-doped SnO₂The slurry was prepared in the same manner as in the slurry 1 except that the particles were set to 20: 100: 15.
[0093]
Then, application and sintering of the slurry 4 were repeated so that the state shown in FIG. 3 was obtained in the same manner as the formation procedure of the photoelectrode 10, thereby forming a counter electrode CE3 having a thickness of 50 μm on the surface of the porous layer PS. .
[0094]
Next, dimethylpropyl imidazolium iodide, lithium iodide, and 4-tert-butylpyridine are dissolved in γ-butyrolactone as a solvent, and a liquid electrolyte (concentration of dimethylpropyl imidazolium iodide: 0.6 mol) is dissolved. / L, concentration of lithium iodide: 0.1 mol / L 4-tert-butylpyridine concentration: 0.5 mol / L).
[0095]
Next, a sealing material S (trade name: “Himilan”, an ethylene / methacrylic acid random copolymer ionomer film) manufactured by Mitsui Dupont Polychemical Co., Ltd. having a shape corresponding to the size of the semiconductor electrode was prepared. As shown in the figure, the semiconductor electrode 2, the porous layer PS and the counter electrode CE3 were arranged on the side exposed to the outside, and were thermally welded to obtain a battery housing (unfilled with electrolyte).
[0096]
Next, after the electrolyte is injected into the housing from the hole of the counter electrode CE3 provided in advance, the hole is closed with a member of the same material as the sealing material S, and the member is thermally welded to the hole of the counter electrode CE3 to form the hole. After sealing, a dye-sensitized solar cell was completed.
[0097]
(Example 2)
According to the following procedure, the dye-sensitized solar cell (the area of the light receiving surface F2 of the semiconductor electrode 2: 1 cm) having the same configuration as the dye-sensitized solar cell 20 shown in FIG.²) Was prepared.
[0098]
First, a photoelectrode 10 having the same configuration as in Example 1 was manufactured according to the same manufacturing procedure and conditions as in Example 1. Next, a liquid electrolyte having the same configuration as in Example 1 was prepared according to the same manufacturing procedure and conditions as in Example 1.
[0099]
Next, a substrate 6 similar to the transparent substrate 4 used for the photoelectrode 10 was prepared, and a slurry 4 similar to that prepared in Example 1 was applied to one surface of the substrate 6, and drying and sintering were repeated. A carbon electrode 8 (thickness: 20 μm) was formed on the substrate 6, and a counter electrode CE1 having the same configuration as that shown in FIG. 1 was produced.
[0100]
A spacer S (trade name: “Himilan”) manufactured by Mitsui Dupont Polychemical Co., Ltd. having a shape corresponding to the size of the semiconductor electrode 2 is prepared, and as shown in FIG. And filled therein with the same electrolyte as that prepared in Example 1 to complete a dye-sensitized solar cell 20 having the same configuration as that shown in FIG.
[0101]
(Comparative Example 1)
When forming the counter electrode CE3, Sb-doped SnO₂Example 1 was repeated except that titania (anatase type titanium oxide) particles (average particle size: 8 nm) were used instead of particles (average particle size: 8 nm). A dye-sensitized solar cell having a similar configuration was manufactured.
[0102]
(Comparative Example 2)
When forming the counter electrode CE1, Sb-doped SnO₂The procedure and conditions of Example 2 were the same as in Example 2 except that titania (anatase type titanium oxide) particles (average particle size: 8 nm) were used instead of particles (average particle size: 8 nm). A dye-sensitized solar cell having a similar configuration was manufactured.
[0103]
[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 Example 1, Example 2, Comparative Example 1, and Comparative Example 2 was measured. The energy conversion efficiency η (%) of the dye-sensitized solar cell is represented by the following equation (A). Here, in the following equation (A), P₀Is the incident light intensity [mWcm^-2], V_ocIs the open circuit voltage [V], J_scIs the short circuit current density [mA · cm^-2F.]. F. Indicates a fill factor (Filling Factor).
η = 100 × (V_oc× J_sc× F. F. ) / P₀… (A)
[0104]
The battery characteristics evaluation test was performed by using a solar simulator (trade name: “WXS-85-H”, manufactured by Wacom) and simulating sunlight irradiation conditions from a xenon lamp light source through an AM filter (AM1.5). 10mW / cm²(Irradiation conditions of so-called “0.1 Sun”) and 100 mW / cm²(The so-called “1 Sun” irradiation conditions) were performed under two measurement conditions.
[0105]
The current-voltage characteristics of each dye-sensitized solar cell were measured at room temperature using an IV tester, and the open-circuit voltage (Voc / V) and short-circuit current density (Jsc / mA · cm) were measured.^-2) And the fill factor (FF), and the energy conversion efficiency η₀[%] Was determined. The obtained results are shown in Table 1 (irradiation conditions of 0.1 Sun) and Table 2 (irradiation conditions of 1 Sun). In addition, “Jsc ＠ 1Sun” shown in Table 1 indicates a value obtained by multiplying Jsc actually obtained under the irradiation condition of 0.1 Sun by 10 times.
[0106]
[Table 1]

[0107]
[Table 2]

[0108]
As is clear from the results shown in Tables 1 and 2, the dye-sensitized solar cells of Examples 1 and 2 exhibited excellent F.D. F. And energy conversion efficiency η.
[0109]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a carbon electrode having high electron conductivity that can promptly cause an electron transfer reaction on the electrode surface. Further, by providing this as a counter electrode, a redox couple (for example, I₃ ⁻/ I⁻And the like.₃ ⁻To I⁻(Reduction reaction to reduce) to a dye-sensitized solar cell having excellent energy conversion efficiency.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing a basic configuration of a first embodiment of a dye-sensitized solar cell of the present invention.
FIG. 2 is a schematic sectional view showing a basic configuration of a second embodiment of the dye-sensitized solar cell of the present invention.
FIG. 3 is a schematic sectional view showing a basic configuration of a third embodiment of the dye-sensitized solar cell of the present invention.
FIG. 4 is a schematic cross-sectional view showing an example of a case where a plurality of the dye-sensitized solar cells shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Transparent electrode, 2 ... Semiconductor electrode, 3 ... Transparent conductive film, 4 ... Transparent substrate, 5 ... Sealing material, 6 ... Transparent substrate, 8 ... Carbon electrode, 9 ... Formed by laser scribe Groove, 10 ... Photoelectrode, 20, 30, 40, 50 ... Dye-sensitized solar cell, CE1, CE2, CE3, CE4 ... Counter electrode, E ... Electrolyte, F1, F2, F3 ... Light receiving surface, F22 ... Semiconductor electrode 2, back surface, S: spacer, PS: porous layer.

Claims (6)

A porous carbon electrode having pores,
A carbon electrode comprising at least carbon black-like particles, graphite-like particles, and conductive oxide particles having a lower electrical resistivity than anatase-type titanium oxide particles as constituent materials. Conditions in which the content W1 of the carbon black-like particles, the content W2 of the graphite-like particles, and the content W3 of the conductive oxide particles are represented by the following formulas (1) and (2). Must be satisfied at the same time,
The carbon electrode according to claim 1, wherein:
0.05 ≦ (W1 / W2) ≦ 0.4 (1)
0.05 ≦ {W3 / (W1 + W2)} ≦ 0.4 (2) The carbon electrode according to claim 1, wherein an electrical resistivity of the conductive oxide particles is 1 × 10 ⁻² Ω · cm or less. The conductive oxide particles are a group consisting 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 any one of claims 1 to 3, wherein the carbon electrode is at least one kind of particles selected from the group consisting of: A photoelectrode having a semiconductor electrode having a light receiving surface and a transparent electrode disposed adjacently on the light receiving surface, and a counter electrode, wherein the semiconductor electrode and the counter electrode are arranged to face each other via an electrolyte; Dye-sensitized solar cell,
The counter electrode is the carbon electrode according to any one of claims 1 to 4,
A dye-sensitized solar cell comprising: 6. 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. The dye-sensitized solar cell according to 1.

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