JP4521737B2 - Solar power plant - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a solar power generation device. In particular, the present invention relates to a solar power generation apparatus using semiconductor fine particles sensitized with a dye.
[0002]
[Prior art]
As for photovoltaic power generation, single crystal silicon solar cells, polycrystalline silicon solar cells, amorphous silicon solar cells, and compound solar cells such as cadmium telluride and indium copper selenide have been put into practical use or are mainly the subject of research and development. When a solar power generation device is used for household or industrial power supply applications, more sunlight is desired to be used, and mounting on window surfaces is also being performed. In order to provide visual enjoyment when using the window surface, it is also useful to arrange things having various colors in a mosaic pattern to make them stained glass. However, to the best of the inventors' knowledge, there is no known example of such a colorful and visually comfortable solar power generation device.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide a photovoltaic power generation apparatus that simultaneously realizes a solution to energy and global environmental problems and a visually comfortable state.
[0004]
[Means for Solving the Problems]
The object of the present invention has been achieved by the following items specifying the present invention.
(1) A photovoltaic power generation apparatus in which at least two types of photovoltaic power generation cells having different visible light absorption characteristics are arranged side by side.
(2) The solar power generation apparatus according to (1), wherein the visible absorption characteristic is derived from physical properties related to the wavelength dependence of photoelectric conversion of the solar power generation cell.
(3) The solar power generation apparatus according to (1) or (2), wherein the solar power generation cell contains an inorganic semiconductor that is spectrally sensitized.
(4) The photovoltaic power generator of (3) above, wherein the inorganic semiconductor is titanium oxide.
(5) The solar power generation device according to (3) or (4), wherein the visible light absorption characteristic is derived from the visible light absorption characteristic of the spectral sensitizer.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
There are several ways to obtain a “solar photovoltaic cell having at least two different visible light absorption characteristics” which is an essential component of the present invention. The first method is a method for producing a cell having different visible light absorption characteristics by creating a photovoltaic power generation cell having a high light transmittance by thinning the film and arranging color filters of various colors on the front surface or the back surface thereof. It is. The light transmittance can be increased or decreased depending on the thickness of the semiconductor. Examples of the color filter include one that absorbs a specific wavelength region of visible light, and one that absorbs or reflects light in a specific wavelength region by utilizing light interference and scattering, and any method may be used.
[0006]
The second method is a method of obtaining cells having different visible light absorption characteristics by providing pores in an opaque photovoltaic power generation cell to transmit light and coloring the light with the above-described various color filters. In this method, the light transmittance can be increased or decreased depending on the area of the pores.
[0007]
Although these methods are easy to realize, there are drawbacks in that the light transmittance and the conversion efficiency of the photovoltaic cell are in a trade-off relationship, and that light energy is wasted by the color filter.
[0008]
A photovoltaic power generation cell whose visible absorption characteristics are derived from the physical properties related to the wavelength dependence of photoelectric conversion of the photovoltaic cell, that is, at least two cells that absorb light only in a specific wavelength range of visible light and perform photoelectric conversion Obviously, when used in combination, there is no such drawback. Examples of such cells include photoelectric conversion elements and photoelectrochemical cells made of spectrally sensitized inorganic semiconductors, which are particularly preferred for the present invention.
[0009]
Hereinafter, a photoelectric conversion element and a photoelectrochemical cell made of a spectrally sensitized inorganic semiconductor particularly preferable for the present invention will be described in detail.
[0010]
First, the configuration and materials of the photoelectric conversion element and the photoelectrochemical cell of the present invention will be described in detail.
[0011]
In the present invention, the dye-sensitized photoelectric conversion element comprises a conductive support, a semiconductor film (photosensitive layer) sensitized with a dye placed on the conductive support, a charge transfer layer, and a counter electrode. The conductive support provided with the semiconductor film functions as a working electrode in the photoelectric conversion element. A photoelectrochemical cell is a device in which this photoelectric conversion element can be used for a battery for working in an external circuit. The photosensitive layer is designed according to the purpose, and may be a single layer structure or a multilayer structure. Light incident on the photosensitive layer excites the dye. The excited dye has electrons with high energy, and these electrons are transferred from the dye to the conduction band of the semiconductor fine particles, and further reach the conductive support by diffusion. At this time, the dye molecule is an oxidant. In the photoelectrochemical cell, electrons on the conductive support return to the dye oxidant through the counter electrode and the charge transfer layer while working in the external circuit, and the dye is regenerated. The semiconductor film serves as the negative electrode of this battery. In the present invention, two or more adsorbing dyes in the semiconductor film are used. In the present invention, at the boundary of each layer (for example, the boundary between the conductive layer and the photosensitive layer of the conductive support, the boundary between the photosensitive layer and the charge transfer layer, the boundary between the charge transfer layer and the counter electrode, etc.) They may be diffused and mixed with each other.
[0012]
In the present invention, the semiconductor is a so-called photoreceptor, and plays a role of absorbing electrons and separating charges to generate electrons and holes. In dye-sensitized semiconductors, light absorption and thus the generation of electrons and holes occurs primarily in the dye, and the semiconductor is responsible for receiving and transmitting these electrons.
[0013]
As a semiconductor, in addition to a single semiconductor such as silicon or germanium, a so-called compound semiconductor represented by a metal chalcogenide (for example, oxide, sulfide, selenide, etc.) or a compound having a perovskite structure can be used. . Preferred metal chalcogenides are titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium or tantalum oxide, cadmium, zinc, lead, silver, antimony, Bismuth sulfide, cadmium, lead selenide, cadmium telluride and the like. Other compound semiconductors include phosphides such as zinc, gallium, indium, cadmium, gallium arsenide, copper-indium-selenide, copper-indium-sulfide, and the like.
[0014]
The compound having a perovskite structure is preferably strontium titanate, calcium titanate, sodium titanate, barium titanate, or potassium niobate.
[0015]
More preferably as a semiconductor used in the present invention, specifically, Si, TiO₂, SnO₂, Fe₂O_Three, WO_Three, ZnO, Nb₂O_Five, CdS, ZnS, PbS, Bi₂S_Three, CdSe, CdTe, GaP, InP, GaAs, CuInS₂, CuInSe₂Is mentioned. More preferably TiO₂, ZnO, SnO₂, Fe₂O_Three, WO_Three, Nb₂O_Five, CdS, PbS, CdSe, InP, GaAs, CuInS₂, CuInSe₂And particularly preferably TiO₂Or Nb₂O_FiveAnd most preferably TiO₂It is.
[0016]
The semiconductor used in the present invention may be single crystal or polycrystalline. As the conversion efficiency, a single crystal is preferable, but a polycrystal is preferable in terms of production cost, securing raw materials, energy payback time, and the like, and a nanometer to micrometer size fine particle semiconductor is particularly preferable.
[0017]
The particle diameter of these semiconductor fine particles is preferably an average particle diameter using a diameter when the projected area is converted into a circle, and is preferably 5 to 200 nm as a primary particle, and particularly preferably 8 to 100 nm. The average particle size of the semiconductor fine particles (secondary particles) in the dispersion is preferably 0.01 to 100 μm.
[0018]
Further, two or more kinds of fine particles having different particle size distributions may be mixed and used. In this case, the average size of the small particles is preferably 5 nm or less. In addition, semiconductor particles having a large particle size, for example, about 300 nm may be mixed for the purpose of scattering incident light and improving the light capture rate.
[0019]
Semiconductor fine particles can be prepared by the sol-gel method described in “Science of sol-gel method” by Sakuhana Sakuo, Agne Jofu Co., Ltd. (1988), “Thin-film coating technology by sol-gel method” (1995), etc. Tadao's “Synthesis of Monodispersed Particles by New Synthetic Method Gel-Sol Method and Control of Size Form” The gel-sol method described in Materia, Vol. 35, No. 9, pages 1012 to 1018 (1996) is preferred.
[0020]
Also preferred is a method of producing an oxide by high-temperature hydrolysis of chloride developed by Degussa in an oxyhydrogen flame.
[0021]
In the case of titanium oxide, the above-mentioned sol-gel method, gel-sol method, and high-temperature hydrolysis method of chloride in an oxyhydrogen flame are all preferred, but Kiyoshi Manabu's “Titanium Oxide Properties and Applied Technology”, published by Gihodo Publishing (1997). The described sulfuric acid method and chlorine method can also be used.
[0022]
In the case of titanium oxide, those described in “Journal of American Ceramic Society Vol. 80, No. 12, pages 3157 to 3171 (1997)” of Barb et al. "Chemical Materials Vol. 10, No. 9, pages 2419 to 2425" is preferred.
[0023]
As the conductive support, a glass or plastic support having a conductive layer (conductive agent layer) containing a conductive agent on the surface thereof can be used, such as a metal that is conductive in itself. In the latter case, preferred conductive agents are metals (eg, platinum, gold, silver, copper, aluminum, rhodium, indium, etc.), carbon, or conductive metal oxides (indium-tin composite oxide, tin oxide doped with fluorine. Etc.). The thickness of the conductive agent layer is preferably about 0.02 to 10 μm.
[0024]
The lower the surface resistance of the conductive support, the better. The preferred surface resistance range is 100 Ω / cm²Or less, more preferably 40Ω / cm²It is as follows. This lower limit is not particularly limited, but is usually 0.1Ω / cm²Degree.
[0025]
The conductive support is preferably substantially transparent. Substantially transparent means that the light transmittance is 10% or more, preferably 50% or more, particularly preferably 70% or more. As the transparent conductive support, a glass or plastic coated with a conductive metal oxide is preferable. Among these, conductive glass in which a conductive layer made of tin dioxide doped with fluorine is deposited on a transparent substrate made of low-cost soda-lime float glass is particularly preferable. Moreover, it is good to use what provided the said conductive layer in the transparent polymer film for a low-cost flexible photoelectric conversion element or a solar cell. Transparent polymer films include tetraacetylcellulose (TAC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), syndioctaic polyester (SPS), polyphenylene sulfide (PPS), polycarbonate (PC), polyarylate (PAr). ), Polysulfone (PSF), polyester sulfone (PES), polyetherimide (PEI), cyclic polyolefin, brominated phenoxy and the like. When a transparent conductive support is used, light is preferably incident from the support side. In this case, the conductive metal oxide coating amount is 1 m of glass or plastic support.²0.01 to 100 g per unit is preferable.
[0026]
It is preferable to use a metal lead for the purpose of reducing the resistance of the transparent conductive substrate. The material of the metal lead is preferably a metal such as aluminum, copper, silver, gold, platinum or nickel, and particularly preferably aluminum or silver. It is preferable to install the metal lead on a transparent substrate by vapor deposition, sputtering, etc., and provide a transparent conductive layer made of tin oxide doped with fluorine or an ITO film thereon. It is also preferable that a metal lead is placed on the transparent conductive layer after providing the transparent conductive layer on the transparent substrate. The decrease in the amount of incident light due to the installation of the metal lead is 1 to 10%, more preferably 1 to 5%.
[0027]
Examples of the method for coating the semiconductor fine particles on the conductive support include a method in which a dispersion or colloidal solution of semiconductor fine particles is applied on the conductive support, and the sol-gel method described above. In consideration of mass production of photoelectric conversion elements, liquid physical properties, and flexibility of a support, a wet film application method is relatively advantageous. As a wet film application method, a coating method and a printing method are typical.
[0028]
In addition to the sol-gel method described above, semiconductor fine particles can be dispersed in a mortar, pulverized using a mill, or dispersed as a fine particle in a solvent during semiconductor synthesis. And a method of using it as it is. Examples of the dispersion medium include water or various organic solvents (for example, methanol, ethanol, isopropyl alcohol, dichloromethane, acetone, acetonitrile, ethyl acetate, etc.). During dispersion, a polymer, surfactant, acid, chelating agent, or the like may be used as a dispersion aid as necessary.
[0029]
The application method is disclosed in Japanese Patent Publication No. 58-4589 as a roller method, a dip method as an application system, an air knife method, a blade method, etc. as a metering system, and the application and metering can be performed in the same part. The wire bar method, the slide hopper method, the extrusion method, the curtain method and the like described in U.S. Pat. Nos. 2,681,294, 2761419, 2761791 and the like are preferable. As a general-purpose machine, a spin method or a spray method is also preferably used.
[0030]
Conventionally, as the wet printing method, intaglio, rubber plate, screen printing and the like are preferred, including the three major printing methods of letterpress, offset and gravure.
[0031]
A preferable film application method is selected from the above methods depending on the liquid viscosity and wet thickness.
[0032]
The liquid viscosity greatly depends on the type and dispersibility of semiconductor fine particles, the type of solvent used, and additives such as surfactants and binders. For high-viscosity liquids (for example, 0.01 to 500 Poise), the extrusion method or casting method is preferable. For low-viscosity liquids (for example, 0.1 Poise or less), the slide hopper method, wire bar method, or spin method is preferable, and a uniform film is formed It is possible.
[0033]
Even in the case of applying a low-viscosity liquid by the extrusion method, the application is possible if the application amount is a certain amount.
[0034]
Further, screen printing is often used for coating a high-viscosity paste of semiconductor fine particles, and this method can also be used.
[0035]
As described above, a wet film applying method may be appropriately selected in accordance with parameters such as the liquid viscosity of the coating liquid, the coating amount, the support, and the coating speed.
[0036]
Further, the semiconductor fine particle-containing layer need not be limited to a single layer. It is also possible to apply multiple layers of dispersions with different particle sizes of particles, or to apply multiple layers of coating layers with different types of semiconductors or different binder and additive compositions. Multi-layer coating is effective even when the film thickness is insufficient. For multilayer coating, an extrusion method or a slide hopper method is suitable. In the case of applying multiple layers, the multiple layers may be applied at the same time, or may be successively applied several times to several dozen times. Further, screen printing can be preferably used as long as it is sequentially overcoated.
[0037]
In general, as the thickness of the semiconductor fine particle-containing layer increases, the amount of the supported dye increases per unit projected area and thus the light capture rate increases. However, since the diffusion distance of the generated electrons increases, the loss due to charge recombination also increases. Therefore, the semiconductor fine particle-containing layer has a preferable thickness, but is typically 0.1 to 100 μm. When used as a photoelectrochemical cell, the thickness is preferably 1 to 30 μm, and more preferably 2 to 25 μm. Semiconductor fine particle support 1m²The coating amount per unit is preferably 0.5 to 400 g, more preferably 5 to 100 g.
[0038]
The semiconductor fine particles are preferably heat-treated in order to bring the particles into electronic contact after being applied to the conductive support, and to improve the strength of the coating film and the adhesion to the support. A preferable heat treatment temperature range is 40 ° C. or higher and lower than 700 ° C., and more preferably 100 ° C. or higher and 600 ° C. or lower. The heat treatment time is about 10 minutes to 10 hours. When using a support having a low melting point or softening point such as a polymer film, high temperature treatment is not preferable because it causes deterioration of the support. Moreover, it is preferable that it is as low temperature as possible also from a viewpoint of cost. The temperature can be lowered by using the above-mentioned small semiconductor particles of 5 nm or less in combination or heat treatment in the presence of a mineral acid.
[0039]
In addition, after heat treatment, for example, chemical plating or aqueous trichloride using a titanium tetrachloride aqueous solution is used to increase the surface area of the semiconductor particles, increase the purity in the vicinity of the semiconductor particles, and increase the efficiency of electron injection from the dye into the semiconductor particles. Electrochemical plating using a titanium aqueous solution may be performed.
[0040]
The semiconductor fine particles preferably have a large surface area so that many dyes can be adsorbed. For this reason, the surface area of the semiconductor fine particle layer coated on the support is preferably 10 times or more, more preferably 100 times or more the projected area. The upper limit is not particularly limited, but is usually about 1000 times.
[0041]
The dye used in the present invention is preferably a complex dye (particularly a metal complex dye) or a methine dye. In the present invention, two or more kinds of pigments can be mixed in order to achieve the target color. And the pigment | dye mixed and the ratio can be selected so that it may match with the wavelength range and intensity distribution of the target color. Such a dye preferably has an appropriate interlocking group for the surface of the semiconductor fine particles. Preferred linking groups include COOH groups and SO_ThreeH group, cyano group, -P (O) (OH)₂Group, -OP (O) (OH)₂Groups or chelating groups having π-conductivity such as oximes, dioximes, hydroxyquinolines, salicylates and α-ketoenolates. Among them, COOH group, -P (O) (OH)₂Group, -OP (O) (OH)₂The group is particularly preferred. These groups may form a salt with an alkali metal or the like, or may form an internal salt. In the case of a polymethine dye, if the methine chain contains an acidic group as in the case where the methine chain forms a squarylium ring or a croconium ring, this part may be used as a linking group.
[0042]
The pigments preferably used in the present invention will be specifically described below.
When the dye used in the present invention is a metal complex dye, a ruthenium complex dye is preferable, and a dye represented by the following formula (I) is more preferable.
Formula (I) (A₁)_pRuB_aB_bB_c
[0043]
In the formula (I), p is 0 to 2, preferably 2. Ru represents ruthenium. A₁Is Cl, SCN, H₂A ligand selected from O, Br, I, CN, NCO, and SeCN. B_a, B_b, B_cAre each independently an organic ligand selected from the following B-1 to B-8.
[0044]
[Chemical 1]
[0045]
Where R_aIs a hydrogen atom, a halogen atom, an alkyl group substituted or unsubstituted with 1 to 12 carbon atoms (hereinafter referred to as C number), a substituted or unsubstituted aralkyl group with 7 to 12 carbon atoms, or a C number 6 to 12 Represents a substituted or unsubstituted aryl group. The alkyl part of the alkyl group or aralkyl group may be linear or branched, and the aryl part of the aryl group or aralkyl group may be monocyclic or polycyclic (condensed ring, ring assembly). It may be.
[0046]
Examples of the ruthenium complex dye used in the present invention include complexes described in U.S. Pat. Nos. 4,927,721, 4,684,537, 5,844,365, 5,350,644, 5,630,57, 5,525,440 and JP-A-7-249790. Pigments.
[0047]
Although the preferable specific example of the metal complex dye used for this invention below is shown, this invention is not limited to these. Examples include dyes E, H, and K used in the examples.
[0048]
[Chemical 2]
[0049]
[Chemical Formula 3]
[0050]
[Formula 4]
[0051]
When the dye used in the present invention is a methine dye, a dye represented by formula (II), formula (III), formula (IV) or formula (V) described below is preferable.
[0052]
[Chemical formula 5]
[0053]
Where R_bAnd R_fEach represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group;_c~ R_eEach represents a hydrogen atom or a substituent. R_b~ R_fMay combine with each other to form a ring. X₁₁And X₁₂Represents nitrogen, oxygen, sulfur, selenium and tellurium, respectively. n₁₁And n₁₃Each represents an integer from 0 to 2;₁₂Represents an integer of 1-6. The compound represented by the formula (II) may have a counter ion according to the charge of the whole molecule.
[0054]
The alkyl group, aryl group and heterocyclic group in the above may have a substituent. The alkyl group may be linear or branched, and the aryl group and heterocyclic group may be monocyclic or polycyclic (fused ring, ring assembly). Also R_b~ R_fThe ring formed by may have a substituent and may be a single ring or a condensed ring.
[0055]
[Chemical 6]
[0056]
Where Z_aRepresents a nonmetallic atom group necessary for forming a nitrogen-containing heterocycle. R_gIs an alkyl group or an aryl group. Q_aRepresents a methine group or polymethine group necessary for the compound represented by the formula (III) to form a methine dye. X₁₃Represents a charge balanced counter ion and n₁₄Represents a number from 0 to 10 necessary for neutralizing the charge of the molecule.
[0057]
Z above_aThe nitrogen-containing heterocyclic ring formed by may have a substituent and may be a monocyclic ring or a condensed ring. In addition, the alkyl group and the aryl group may have a substituent, the alkyl group may be linear or branched, and the aryl group may be monocyclic or polycyclic (fused ring, Ring assembly).
[0058]
The dye represented by the formula (III) is preferably a dye represented by the following formulas (III-a) to (III-d).
[0059]
[Chemical 7]
[0060]
In formulas (III-a) to (III-d), R₁₁~ R₁₅, R_{twenty one}~ R_{twenty four}, R₃₁~ R₃₃And R₄₁~ R₄₃Each independently represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group;₁₁, Y₁₂, Y_{twenty one}, Y_{twenty two}, Y₃₁~ Y₃₅, And Y₄₁~ Y₄₆Are independently oxygen, sulfur, selenium, tellurium, -CR₁₆R₁₇-, Or -NR₁₈-Represents. R₁₆~ R₁₈Each independently represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group. Y_{twenty three}Is O-, S-, Se-, Te-, or -NR₁₈-Represents.
[0061]
V₁₁, V₁₂, V_{twenty one}, V_{twenty two}, V₃₁And V₄₁Each independently represents a substituent, and n₁₅, N₃₁And n₄₁Each independently represents an integer of 1-6. The compounds represented by the formulas (III-a) to (III-d) may have a counter ion according to the charge of the whole molecule.
[0062]
The alkyl group, aryl group and heterocyclic group in the above may have a substituent, the alkyl group may be linear or branched, and the aryl group and heterocyclic group are monocyclic. Alternatively, it may be a polycycle (fused ring, ring assembly).
[0063]
Specific examples of the polymethine dye as described above are described in detail in M. Okawara, T. Kitao, T. Hirasima, Organic Colorants (Elsevier) by M. Matuoka, and the like.
[0064]
[Chemical 8]
[0065]
In formula (IV), Q_bRepresents an atomic group necessary to complete a 5- or 6-membered nitrogen-containing heterocycle, and Q_bMay be condensed and may have a substituent. Q_bPreferred examples of the heterocyclic ring completed in benzothiazole nucleus, benzoxazole nucleus, benzoselenazole nucleus, benzotelrazole nucleus, 2-quinoline nucleus, 4-quinoline nucleus, benzimidazole nucleus, thiazoline nucleus, indolenine nucleus Oxadiazole nucleus, thiazole nucleus, imidazole nucleus, more preferably benzothiazole nucleus, benzoxazole nucleus, benzimidazole nucleus, benzoselenazole nucleus, 2-quinoline nucleus, 4-quinoline nucleus, indolenine nucleus. Particularly preferred are a benzothiazole nucleus, a benzoxazole nucleus, a 2-quinoline nucleus, a 4-quinoline nucleus, and an indolenine nucleus. Examples of substituents on the ring include carboxylic acid group, phosphonic acid group, sulfonic acid group, halogen atom (F, Cl, Br, I), cyano group, alkoxy group (methoxy, ethoxy, methoxyethoxy, etc.), aryloxy group ( Phenoxy, etc.), alkyl groups (methyl, ethyl, cyclopropyl, cyclohexyl, trifluoromethyl, methoxyethyl, allyl, benzyl, etc.), alkylthio groups (methylthio, ethylthio, etc.), alkenyl groups (vinyl, 1-propenyl, etc.) Aryl group or heterocyclic group (phenyl, thienyl, toluyl, chlorophenyl, etc.) and the like.
[0066]
Z_bRepresents an atomic group necessary for completing a 3- to 9-membered ring composed of atoms selected from a carbon atom, an oxygen atom, a nitrogen atom, a sulfur atom and a hydrogen atom. Z_bThe ring completed by is preferably a ring having a skeleton formed by 4 to 6 carbons, more preferably those represented by the following (a) to (e), and most preferably (a) It is.
[0067]
[Chemical 9]
[0068]
L₁, L₂, L_Three, L_FourAnd L_FiveEach independently represents a methine group optionally having a substituent. Examples of the substituent include a substituted or unsubstituted alkyl group (preferably having 1 to 12 carbon atoms, more preferably 1 to 7 carbon atoms such as methyl, ethyl, propyl, isopropyl, cyclopropyl, butyl, 2-carboxyl. Ethyl, benzyl, etc.), substituted or unsubstituted aryl groups (preferably having 6 to 10 carbon atoms, more preferably 6 to 8 carbon atoms, such as phenyl, toluyl, chlorophenyl, o-carboxyphenyl), heterocyclic rings Groups (eg pyridyl, thienyl, furanyl, pyridyl, barbituric acid), halogen atoms (eg chlorine, bromine), alkoxy groups (eg methoxy, ethoxy), amino groups (preferably having 1 to 12 carbon atoms, Preferably 6 to 12, for example diphenylamino , Methylphenylamino, 4-acetyl-piperazin-1-yl), etc. oxo group. These substituents on the methine group may be linked to each other to form a ring such as a cyclopentene ring, a cyclohexene ring, a squarylium ring, or a ring with an auxiliary color group.
[0069]
n₅₁Represents an integer of 0 to 4, preferably 0 to 3. n₅₂Is 0 or 1.
[0070]
R_FiveRepresents a substituent. The substituent is preferably an aromatic group which may have a substituent or an aliphatic group which may have a substituent, and the aromatic group preferably has 1 to 16 carbon atoms, more preferably 5 6 to 6. The number of carbon atoms of the aliphatic group is preferably 1 to 10, more preferably 1 to 6. Examples of the unsubstituted aliphatic group and aromatic group include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, a phenyl group, and a naphthyl group.
[0071]
W₁Represents a counter ion when a counter ion is required to neutralize the charge. Whether a dye is a cation, an anion, or has a net ionic charge depends on its auxiliary chromophore and substituent. When the substituent has a dissociable group, it may be dissociated and have a negative charge. In this case, the charge of the entire molecule is₁Neutralized by. Typical cations are inorganic or organic ammonium ions (eg, tetraalkylammonium ions, pyridinium ions) and alkali metal ions, while anions are specifically inorganic or organic anions. Well, for example, a halogen anion (eg, fluoride ion, chloride ion, bromide ion, iodide ion), substituted aryl sulfonate ion (eg, p-toluene sulfonate ion, p-chlorobenzene sulfonate ion), Aryl disulfonate ion (for example, 1,3-benzenedisulfonate ion, 1,5-naphthalenedisulfonate ion, 2,6-naphthalenedisulfonate ion), alkyl sulfate ion (for example, methyl sulfate ion), sulfate ion, thiocyanate Acid ion, perchlorine Ion, tetrafluoroborate ion, picrate ion, acetate ion and trifluoromethanesulfonate ion.
[0072]
Furthermore, an ionic polymer or other dye having a charge opposite to that of the dye may be used as the charge balance counter ion, or a metal complex ion (for example, bisbenzene-1,2-dithiolatonickel (III)) is also possible. is there.
[0073]
[Chemical Formula 10]
[0074]
In the formula (V), D represents an aromatic group having at least four functional groups, and X₁, X₂Are independently sulfur, selenium, CR₆₃R₆₄Or CR₆₅= CR₆₆Represents. Where R₆₃~ R₆₆Are each a hydrogen atom or an alkyl group. R₆₁, R₆₂Are each an alkyl group or an aromatic group, and P₁, P₂Each independently represents a group of nonmetallic atoms necessary to form a polymethine dye. W₂Indicates the counter ion when a counter ion is required to neutralize the charge.
[0075]
Formula (V) will be described in more detail.
In formula (V), D represents at least a tetrafunctional or higher functional aromatic group. Examples of such aromatic groups include benzene, naphthalene, anthracene, phenanthrene and the like as aromatic hydrocarbons from which these groups are derived, and examples of aromatic heterocycles include anthraquinone, carbazole, pyridine, quinoline, Examples include thiophene, furan, xanthene, and thianthrene, which may have a substituent in addition to the linking moiety. The aromatic group represented by D is preferably an aromatic hydrocarbon derivative group, and more preferably a benzene or naphthalene derivative group.
[0076]
X₁, X₂Is preferably a sulfur atom or CR₆₃R₆₄And most preferably CR₆₃R₆₄It is.
[0077]
P₁, P₂Each independently represents a group of nonmetallic atoms necessary to form a polymethine dye. P₁, P₂It is possible to form any methine dye, preferably cyanine dye, merocyanine dye, rhodacyanine dye, trinuclear merocyanine dye, allopolar dye, hemicyanine dye, styryl dye and the like. In this case, cyanine dyes include those in which a substituent on the methine chain forming the dye forms a squalium ring or a croconium ring. For more information on these dyes, see FMHarmer, “Heterocyclic Compounds-Cyanine Dyes and Related Compounds”, John Willie &・ John Wiley & Sons-New York, London, 1964, DMSturmer "Heterocyclic Compounds- Heterocyclic Compounds- Special topics in cyclic chemistry) ", Chapter 18, Section 14, 482-515 Mitsugu. The formulas of cyanine dye, merocyanine dye, and rhodacyanine dye are preferably those shown in (XI), (XII), and (XIII) of US Pat. No. 5,340,694, No. 21,22. P₁And P₂Are preferably those having a squarylium ring in at least one of the methine chain portions of the polymethine dye formed by, and more preferably those having both.
[0078]
R₆₁, R₆₂Is an aromatic group or an aliphatic group, and these may have a substituent. The number of carbon atoms of the aromatic group is preferably 5 to 16, more preferably 5 to 6. The number of carbon atoms of the aliphatic group is preferably 1 to 10, more preferably 1 to 6. Examples of the unsubstituted aliphatic group and aromatic group include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, a phenyl group, and a naphthyl group.
[0079]
Formula (V) is R₆₁, R₆₂, P₁, P₂It is preferable that at least one of them has an acidic group. Here, the acidic group is a substituent having a dissociable proton, and examples thereof include carboxylic acid, phosphonic acid, sulfonic acid, boric acid and the like, and preferably carboxylic acid. Further, such an acidic group may take a form of releasing a proton and dissociating.
[0080]
W₂Is W in formula (IV)₁It is synonymous with.
[0081]
Preferred specific examples of polymethine dyes represented by formulas (II) to (V) are shown below, but the present invention is not limited to these. The dyes B, D, F, G, I and K used in the examples are also mentioned.
[0082]
Embedded image
[0083]
Embedded image
[0084]
Embedded image
[0085]
Embedded image
[0086]
Embedded image
[0087]
Embedded image
[0088]
Embedded image
[0089]
Embedded image
[0090]
Embedded image
[0091]
Embedded image
[0092]
Embedded image
[0093]
Embedded image
[0094]
Embedded image
[0095]
Embedded image
[0096]
Embedded image
[0097]
Embedded image
[0098]
Embedded image
[0099]
Embedded image
[0100]
Embedded image
[0101]
Embedded image
[0102]
Embedded image
[0103]
The compounds represented by the formulas (II) and (III) are described in FMHarmer, “Heterocyclic Compounds-Cyanine Dyes and Related Compounds”. ”, John Wiley & Sons-New York, London, 1964, DMSturmer,“ Complex Cyclic Compounds Special Topics in Complex Si ” Heterocyclic Compounds-Special topics in cyclic chemistry, Chapter 18, Section 14, 482-515, John Wiley & Sons, New York, London, 1977 , “Rodd's Chemistry of Carbon Compounds” Vol. IV, part B, 1977, Chapter 15, pp. 369-422, published by Elsevier Science Publishing Company Inc., New York, UK Patent No. 1,077,611 Can be synthesized based on the method described in the above.
[0104]
The compound represented by the formula (IV) used in the present invention can be synthesized with reference to descriptions in literature such as Dyes and Pigments Vol. 21, pp. 227-234. Further, the synthesis of the compound represented by the formula (V) is described in Ukrainskii Khimicheskii Zhurnal Vol. 40, No. 3, pp. 253-258, Dyes and Pigments, Vol. 21, pp. 227-234, and descriptions of references cited in these documents. It can be done with reference to etc.
[0105]
As a method for adsorbing the dye to the semiconductor fine particles, a method of immersing a working electrode containing well-dried semiconductor fine particles in the dye solution or applying the dye solution to the semiconductor fine particle layer and adsorbing can be used. In the former case, dipping method, dipping method, roller method, air knife method, etc. can be used. Examples of the latter application method include a wire bar method, a slide hopper method, an extrusion method, a curtain method, a spin method, and a spray method. Examples of the printing method include letterpress, offset, gravure, and screen printing.
[0106]
As with the formation of the semiconductor fine particle layer, the liquid viscosity is not limited to the extrusion method for high-viscosity liquids (for example, 0.01 to 500 poise), and various printing methods are used for the low-viscosity liquid (for example, 0.1 poise or less). Alternatively, a wire bar method or a spin method is suitable, and a uniform film can be obtained.
[0107]
As described above, the application method may be appropriately selected according to the parameters such as the viscosity of the dye coating solution, the coating amount, the support, and the coating speed. The time required for the dye adsorption after coating is preferably as short as possible when mass production is considered.
[0108]
The total amount of dye used is 1m on the support.²0.01 to 100 mmol is preferred per unit. Further, the adsorption amount of the dye to the semiconductor fine particles is preferably 0.01 to 1 mmol with respect to 1 g of the semiconductor fine particles. By using such a dye amount, a sensitizing effect in a semiconductor can be sufficiently obtained. On the other hand, when the amount of the dye is small, the sensitizing effect is insufficient, and when the amount of the dye is too large, the dye not attached to the semiconductor floats and causes the sensitizing effect to be reduced.
[0109]
Since the presence of unadsorbed dye causes disturbance in device performance, it is preferable to remove it by washing immediately after adsorption. It is preferable to use a wet cleaning tank and wash with a polar solvent such as acetonitrile or an organic solvent such as an alcohol solvent. In order to increase the amount of adsorbed dye, it is preferable to perform the heat treatment before adsorption. In order to prevent water from adsorbing to the surface of the semiconductor fine particles after the heat treatment, it is also preferable to quickly adsorb the dye between 40 to 80 ° C. without returning to normal temperature. In addition, for the purpose of promoting the removal of excess dye, the surface of the semiconductor fine particles may be treated with amines after adsorbing the dye. Preferable amines include pyridine, 4-tert-butylpyridine, polyvinylpyridine and the like. When these are liquids, they may be used as they are or may be used after being dissolved in an organic solvent.
[0110]
Further, a colorless compound may be co-adsorbed for the purpose of reducing the interaction between dyes such as association. Examples of the hydrophobic compound to be co-adsorbed include steroid compounds having a carboxyl group (for example, cholic acid).
[0111]
Furthermore, an ultraviolet absorber can be co-adsorbed for the purpose of preventing photodegradation due to ultraviolet rays.
[0112]
Hereinafter, the charge transfer layer and the counter electrode will be described in detail.
The charge transfer layer is a layer having a function of replenishing electrons to the oxidant of the dye. Examples of typical charge transfer layers that can be used in the present invention include a liquid (electrolytic solution) in which a redox couple is dissolved in an organic solvent, a so-called gel in which a polymer matrix is impregnated with a liquid in which a redox couple is dissolved in an organic solvent. Examples thereof include an electrolyte and a molten salt containing a redox couple. Furthermore, a solid electrolyte or a hole (hole) transport material can also be used.
[0113]
The electrolytic solution used in the present invention is preferably composed of an electrolyte, a solvent, and an additive. The electrolyte of the present invention is I₂And iodide (as iodide, LiI, NaI, KI, CsI, CaI₂Metal iodides such as tetraalkylammonium iodide, pyridinium iodide, imidazolium iodide and the like quaternary ammonium compounds such as iodine salts), Br₂And bromide combinations (LiBr, NaBr, KBr, CsBr, CaBr as bromides)₂Metal bromide such as tetraalkylammonium bromide, pyridinium bromide, bromide salts of quaternary ammonium compounds), metal complexes such as ferrocyanate-ferricyanate and ferrocene-ferricinium ions, sodium polysulfide, Sulfur compounds such as alkylthiol-alkyldisulfides, viologen dyes, hydroquinone-quinones, and the like can be used. I among them₂In the present invention, an electrolyte obtained by combining iodine salt of a quaternary ammonium compound such as LiI, pyridinium iodide, imidazolium iodide and the like is preferable. The electrolytes described above may be used in combination. Further, the electrolyte is a room temperature described in EP-718288, WO95 / 18456, J. Electrochem. Soc., Vol. 143, No. 10, 3099 (1996), Inorg. Chem. 1996, 35, 1168-1178. It is also possible to use a molten salt (molten salt). When using a molten salt as an electrolyte, the solvent may not be used.
[0114]
A preferable electrolyte concentration is 0.1 M or more and 15 M or less, and more preferably 0.2 M or more and 10 M or less. Moreover, the preferable addition concentration of iodine when adding iodine to the electrolyte is 0.01 M or more and 0.5 M or less.
[0115]
The solvent used for the electrolyte in the present invention is a compound that has low viscosity and improved ion mobility, or has a high dielectric constant and improved effective carrier concentration, and can exhibit excellent ion conductivity. desirable. Examples of the solvent include carbonate compounds such as ethylene carbonate and propylene carbonate, heterocyclic compounds such as 3-methyl-2-oxazolidinone, ether compounds such as dioxane and diethyl ether, ethylene glycol dialkyl ether, propylene glycol dialkyl ether, and polyethylene. Chain ethers such as glycol dialkyl ether and polypropylene glycol dialkyl ether, alcohols such as methanol, ethanol, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, polyethylene glycol monoalkyl ether, polypropylene glycol monoalkyl ether, ethylene glycol, Propylene glycol, polyethylene glycol, polyp Use polyhydric alcohols such as pyrene glycol and glycerol, nitrile compounds such as acetonitrile, glutarodinitrile, methoxyacetonitrile, propionitrile, and benzonitrile, aprotic polar substances such as dimethyl sulfoxide (DMSO) and sulfolane, and water. be able to.
[0116]
Further, in the present invention, a base such as ter-butylpyridine, 2-picoline, 2,6-lutidine and the like described in J. Am. Ceram. Soc., 80 (12) 3157-3171 (1997) Sexual compounds can also be added. A preferable concentration range when adding a basic compound is 0.05M or more and 2M or less.
[0117]
In the present invention, the electrolyte can be used after gelation (solidification) by a technique such as addition of a polymer, addition of an oil gelling agent, polymerization including polyfunctional monomers, or a crosslinking reaction of the polymer. In the case of gelation by adding a polymer, compounds described in Polymer Electrolyte Reviews-1 and 2 (JR MacCallum and CA Vincent, edited by ELSEVIER APPLIED SCIENCE) can be used, but in particular, polyacrylonitrile and polyfluoride are used. Vinylidene chloride can be preferably used. J. Chem Soc. Japan, Ind. Chem. Soc., 46779 (1943), J. Am. Chem. Soc., 111,5542 (1989), J. Chem. Soc ., Chem. Com mun., 1993, 390, Angew. Chem. Int. Ed. Engl., 35, 1949 (1996), Chem. Lett., 1996, 885, J. Chm. Soc., Chem. Commun. , 1997, 545 can be used, but preferred compounds are those having an amide structure in the molecular structure.
[0118]
When gel electrolyte is formed by polymerization of polyfunctional monomers, a solution is prepared from polyfunctional monomers, polymerization initiator, electrolyte and solvent, and dye is supported by methods such as casting, coating, dipping, and impregnation. A method in which a sol-like electrolyte layer is formed on the prepared electrode and then gelled by radical polymerization is preferred. The polyfunctional monomer is preferably a compound having two or more ethylenically unsaturated groups. For example, divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, Preferred examples include ethylene glycol diacrylate, triethylene glycol dimethacrylate, pentaerythritol triacrylate, and trimethylolpropane triacrylate. The monomers constituting the gel electrolyte may contain a monofunctional monomer in addition to these, and esters or amides derived from acrylic acid or α-alkyl acrylic acid (for example, methacrylic acid) (for example, N-iso). -Propylacrylamide, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, acrylamidepropyltrimethylammonium chloride, methyl acrylate, hydroxyethyl acrylate, n-propyl acrylate, n-butyl acrylate, 2-methoxyethyl acrylate, cyclohexyl acrylate, etc.) , Vinyl esters (eg vinyl acetate), esters derived from maleic acid or fumaric acid (eg dimethyl maleate, dibutyl maleate, diethyl fumarate, etc.), Rain acid, fumaric acid, sodium salt of p-styrene sulfonic acid, acrylonitrile, methacrylonitrile, dienes (eg butadiene, cyclopentadiene, isoprene), aromatic vinyl compounds (eg styrene, p-chlorostyrene, sodium styrene sulfonate) ), A vinyl compound having a nitrogen-containing heterocyclic ring, a vinyl compound having a quaternary ammonium salt, N-vinylformamide, N-vinyl-N-methylformamide, vinylsulfonic acid, sodium vinylsulfonate, vinylidene fluoride, vinylidene chloride, Vinyl alkyl ethers (for example, methyl vinyl ether), ethylene, propylene, 1-butene, isobutene, N-phenylmaleimide and the like can be preferably used. The preferred weight composition range of the polyfunctional monomer in the total amount of the monomers is preferably 0.5% by weight or more and 70% by weight or less, and more preferably 1.0% by weight or more and 50% by weight or less.
[0119]
The above-mentioned monomers are common polymers described in Takayuki Otsu and Masato Kinoshita: Experimental methods for polymer synthesis (Chemical Doujin) and Takayuki Otsu: Lecture Polymerization Reaction Theory 1 Radical Polymerization (I) (Chemical Doujin) It can superpose | polymerize by radical polymerization which is a synthetic method. The monomer for gel electrolyte that can be used in the present invention can be radically polymerized by heating, light, electron beam, or electrochemically, and it is particularly preferable to radically polymerize by heating. Polymerization initiators preferably used when the crosslinked polymer is formed by heating are, for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), Azo initiators such as dimethyl 2,2'-azobis (2-methylpropionate) (dimethyl 2,2'-azobisisobutyrate), peroxide initiators such as benzoyl peroxide, and the like. A preferable addition amount of the polymerization initiator is 0.01% by weight or more and 20% by weight or less, more preferably 0.1% by weight or more and 10% by weight or less with respect to the total amount of monomers.
[0120]
The weight composition range of the monomers in the gel electrolyte is preferably 0.5 wt% or more and 70 wt% or less, more preferably 1.0 wt% or more and 50 wt% or less.
[0121]
Further, when the electrolyte is gelled by a polymer crosslinking reaction, it is desirable to use a polymer containing a crosslinkable reactive group and a crosslinking agent in combination. In this case, a preferable crosslinkable reactive group is a nitrogen-containing heterocyclic ring (for example, a pyridine ring, an imidazole ring, a thiazole ring, an oxazole ring, a triazole ring, a morpholine ring, a piperidine ring, a piperazine ring), and a preferable crosslinking agent. Is a bifunctional or higher functional reagent (for example, alkyl halide, halogenated aralkyl, sulfonate ester, acid anhydride, acid chloride, isocyanate, etc.) capable of electrophilic reaction with a nitrogen atom.
[0122]
In the present invention, a hole transport material combining organic or inorganic or a combination of both can be used instead of the electrolyte. Organic hole transport materials applicable to the present invention include N, N′-diphenyl-N, N′-bis (4-methoxyphenyl)-(1,1′-biphenyl) -4,4′-diamine ( J. Hagen et al., Synthetic Metal 89 (1997) 215-220), 2,2 ', 7,7'-tetrakis (N, N-di-p-methoxyphenylamine) 9,9'-spirobifluorene (Nature, Vol. 395, 8 Oct. 1998, p583-585 and WO97 / 10617), 1,1-bis {4- (di-p-tolylamino) phenyl} cyclohexane tertiary aromatic amine unit linked fragrance Group diamine compounds (Japanese Patent Laid-Open No. 59-194393), including 2,4, -bis [(N-1-naphthyl) -N-phenylamino] biphenyl and two or more tertiary amines An aromatic amine in which the above condensed aromatic ring is substituted with a nitrogen atom (Japanese Patent Laid-Open No. 5-234681), an aromatic triamine having a starburst structure with a derivative of triphenylbenzene (US Pat. No. 4, 923,774, JP-A-4-308688), N, N′-diphenyl-N, N′-bis (3-methylphenyl)-(1,1′-biphenyl) -4,4′-diamine, etc. Aromatic diamine (US Pat. No. 4,764,625), α, α, α ′, α′-tetramethyl-α, α′-bis (4-di-p-tolylaminophenyl) -p-xylene (Japanese Patent Laid-Open No. 3-269084), p-phenylenediamine derivatives, sterically asymmetric triphenylamine derivatives as a whole molecule (Japanese Patent Laid-Open No. 4-129271), and a pyrenyl group substituted with a plurality of aromatic diamino groups Compounds (Japanese Patent Laid-Open No. 4-175395), aromatic diamines having tertiary aromatic amine units linked by ethylene groups (Japanese Patent Laid-Open No. 4-264189), aromatic diamines having a styryl structure (Japanese Patent Laid-Open No. 4-290851) Publication), benzylphenyl compounds (JP-A-4-364153), and those in which a tertiary amine is linked by a fluorene group (JP-A-2004-364153) 5-25473), triamine compounds (JP-A-5-239455), pisdipyridylaminobiphenyl (JP-A-5-320634), N, N, N-triphenylamine derivatives (JP-A-6-1972) Gazette), aromatic diamines having a phenoxazine structure (Japanese Patent Application No. 5-290728), diaminophenylphenanthridine derivatives (Japanese Patent Application No. 6-45669) and the like, α-octylthiophene and α, ω-dihexyl-α-octylthiophene (Adv. Mater. 1997, 9, N0.7, p557), hexadodecyl dodecithiophene (Angew. Chem. Int. Ed. Engl. 1995, 34, No. 3, p303-307), 2,8-dihexylanthra [2,3-b: 6,7-b '] dithiophene (JACS, Vol120, N0.4,1998, p664-672) and other oligothiophene compounds, polypyrrole (K Murakoshi et al.,; Chem. Lett. 1997, p471), ¨ Handbook of Organic Conductive Molecules and Polymers Vol.1,2,3,4¨ (by NALWA, published by WILEY) Polyacetylene and derivatives thereof, poly (p-phenylene) and derivatives thereof, poly (p-phenylene vinylene) and derivatives thereof, polythienylene vinylene and derivatives thereof, polythiophene and derivatives thereof, polyaniline and derivatives thereof, poly Conductive polymers such as toluidine and its derivatives can be preferably used. In addition, organic hole transport materials include tris (4-bromophenyl) aminium hexachloro to control the dopant level as described in Nature, Vol. 395, 8 Oct. 1998, p583-585. Li [(CF to add a compound containing a cation radical such as antimonate or to control the potential of the oxide semiconductor surface (compensation of the space charge layer)_ThreeSO₂)₂A salt such as N] may be added.
[0123]
The organic hole transport material can be introduced into the electrode by techniques such as vacuum deposition, casting, coating, spin coating, dipping, electrolytic polymerization, and photoelectrolytic polymerization. In addition, when a hole transport material is used instead of the electrolyte, a thin layer of titanium dioxide is formed by using a technique such as spray pyrolysis described in Electorochim. Acta 40, 643-652 (1995) to prevent short circuit. It is preferable to coat as an undercoat layer.
[0124]
When inorganic solid compounds are used instead of electrolytes, copper iodide (p-CuI) (J. Phys. D: Appl. Phys. 31 (1998) 1492-1496), copper thiocyanide (Thin Solid Films 261 (1995) 307-310, J. Appl. Phys. 80 (8), 15 October 1996, p4749-4754, Chem. Mater. 1998, 10, 1501-1509, Semicond. Sci. Technol. 10, 1689-1693) It can be introduced into the electrode by techniques such as casting, coating, spin coating, dipping, and electrolytic plating.
[0125]
There are two possible methods for forming the charge transfer layer. One is a method in which a counter electrode is first pasted on a semiconductor fine particle-containing layer carrying a sensitizing dye, and a liquid charge transfer layer is sandwiched in the gap. The other is a method of directly providing a charge transfer layer on the semiconductor fine particle-containing layer, and the counter electrode is subsequently applied.
[0126]
As the sandwiching method of the charge transfer layer in the former case, a normal pressure process using a capillary phenomenon due to immersion or a vacuum process in which the gas phase is replaced with a liquid phase at a pressure lower than normal pressure can be used.
[0127]
In the latter case, in the wet charge transfer layer, a counter electrode is provided without being dried, and measures for preventing liquid leakage at the edge portion are also taken. In the case of a gel electrolyte, there is a method of applying it in a wet state and solidifying it by a method such as polymerization, in which case the counter electrode can be applied after drying and fixing. In addition to the electrolytic solution, wet organic hole transport materials and gel electrolytes can be applied in the same manner as semiconductor fine particle containing layers and pigments, as well as immersion, roller method, dipping method, air knife method, extrusion method, slide A hopper method, a Werber method, a spin method, a spray method, a casting method, various printing methods, and the like can be considered. In the case of a solid electrolyte or a solid hole transport material, a charge transfer layer can be formed by a dry film formation process such as a vacuum deposition method or a CVD method, and then a counter electrode can be provided.
[0128]
When considering mass production, in the case of an electrolyte solution or a wet hole transport material that cannot be solidified, it is possible to respond by sealing the edge portion immediately after coating, but solidified hole transport In the case of materials, it is more preferable to form a hole transport layer by wet application and then solidify by a method such as photopolymerization or thermal radical polymerization. As described above, the film application method may be appropriately selected depending on the liquid properties and process conditions.
[0129]
The moisture in the charge transfer layer is preferably 10,000 ppm or less, more preferably 2,000 ppm or less, and particularly preferably 100 ppm or less.
[0130]
The counter electrode functions as a positive electrode of the photoelectrochemical cell when the photoelectric conversion element is a photoelectrochemical cell. As the counter electrode, a support having a conductive layer can be used in the same manner as the conductive support described above, but the support is not necessarily required in a configuration in which the strength and the sealing performance are sufficiently maintained. Specifically, the conductive material used for the counter electrode is metal (for example, platinum, gold, silver, copper, aluminum, rhodium, indium, etc.), carbon, or conductive metal oxide (indium-tin composite oxide, tin oxide). And the like doped with fluorine. The thickness of the counter electrode is not particularly limited, but is preferably 3 nm or more and 10 μm or less. In the case of a metal material, the film thickness is preferably 5 μm or less, more preferably 5 nm or more and 3 μm or less.
[0131]
In order for light to reach the photosensitive layer, at least one of the conductive support and the counter electrode must be substantially transparent. In the photoelectrochemical cell of the present invention, the conductive support is preferably transparent, and sunlight is preferably incident from the support side. In this case, it is more preferable that the counter electrode has a property of reflecting light. In the present invention, glass or plastic on which a metal or conductive oxide is deposited or a metal thin film can be used as the counter electrode.
[0132]
As described in the application of the charge transfer layer, there are two types of application of the counter electrode: application on the charge transfer layer and application on the semiconductor fine particle-containing layer first. In either case, the counter electrode material can be appropriately formed on the charge transfer layer or the semiconductor fine particle-containing layer by a method such as coating, laminating, vapor deposition, or bonding depending on the type of the counter electrode material or the type of the charge transfer layer. For example, in the case where the counter electrode is bonded, a substrate provided as a conductive layer can be bonded by a method such as application, vapor deposition, or CVD of the conductive material. Further, when the charge transfer layer is solid, the counter electrode can be directly formed on the charge transfer layer by a method such as coating, plating, PVD, or CVD.
[0133]
Furthermore, it is possible to provide a layer having other necessary functions such as a protective layer and an antireflection film on the conductive support or the counter electrode of the working electrode. When such a layer is functionally separated in multiple layers, simultaneous multilayer coating or sequential coating can be performed, but simultaneous multilayer coating is more preferable when productivity is given priority. In simultaneous multilayer coating, the slide hopper method and the extrusion method are suitable when considering productivity and film application uniformity. Moreover, these functional layers can also be provided using methods, such as vapor deposition and affixing, with the material.
[0134]
In the photoelectrochemical cell of the present invention, it is preferable to seal the side surface of the battery with a polymer, an adhesive or the like in order to prevent deterioration of the constituents and volatilization of the contents.
[0135]
Next, a cell structure and a module structure when the photoelectric conversion element of the present invention is applied to a so-called solar battery will be described. The solar power generation device in the present invention is a combination of at least two types of cells having different visible light absorption characteristics (that is, having different colors).
[0136]
The structure of the inside of the cell of the dye-sensitized solar cell is basically the same as that of the above-described photoelectric conversion element or photoelectrochemical cell, but various forms are possible according to the purpose as shown in FIG. 2 or FIG. It is. If roughly divided into two, a structure that allows light to enter from both sides [FIGS. 2 (a) (d), 3 (g)] and a type that can be incident only from one side [FIGS. 2 (b) (c), FIG. 3 (e) (f) (h)].
[0137]
FIG. 2A shows a dye-adsorbing TiO which is a dye-adsorbing semiconductor fine particle-containing layer between the transparent conductive layers 12.₂In this structure, the layer 10 and the charge transfer layer 11 are interposed. FIG. 2B shows a case where a part of the metal lead 9 is provided on the transparent substrate 13, the transparent conductive layer 12 is further provided, the undercoat layer 14, the dye adsorbing TiO 2.₂The layer 10, the charge transfer layer 11, and the metal layer 8 are provided in this order, and the support substrate 15 is further arranged. In FIG. 2C, the metal layer 8 is further provided on the support substrate 15, and the dye-adsorbed TiO is provided via the undercoat layer.₂In this structure, a layer 10 is provided, a charge transfer layer 11 and a transparent conductive layer 12 are provided, and a transparent substrate 13 provided with a metal lead 9 in part is disposed with the metal lead 9 side inward. FIG. 2D shows a case where a part of the metal lead 9 is provided on the transparent substrate 13 and the transparent conductive layer 12 is further provided between the undercoat layer 14 and the dye adsorbing TiO.₂In this structure, the layer 10 and the charge transfer layer 11 are interposed. FIG. 3E shows a transparent substrate 13 having a transparent conductive layer 12 and a dye-adsorbed TiO through an undercoat layer 14.₂In this structure, the layer 10 is provided, the charge transfer layer 11 and the metal layer 8 are further provided, and the support substrate 15 is disposed thereon. FIG. 3 (f) shows a metal adsorbing TiO having a metal layer 8 on a support substrate 15 and an undercoat layer 14.₂In this structure, the layer 10 is provided, the charge transfer layer 11 and the transparent conductive layer 12 are further provided, and the transparent substrate 13 is disposed thereon. FIG. 3G shows an undercoat layer 14 and a dye-adsorbed TiO between the transparent substrates 13 having the transparent conductive layer 12 with the transparent conductive layer 12 inside.₂In this structure, the layer 10 and the charge transfer layer 11 are interposed. FIG. 3 (h) shows a case where the metal layer 8 is provided on the support substrate 15 and the dye-adsorbed TiO is provided via the undercoat layer 14.₂In this structure, the layer 10 is provided, the solid charge transfer layer 16 is further provided, and the metal layer 8 or the metal lead 9 is partially provided thereon.
[0138]
The module structure of the dye-sensitized solar cell of the present invention can be basically the same as that of a conventional solar cell module. In general, a cell is formed on a support substrate such as metal or ceramic, and the cell is covered with a filling resin or protective glass, and light can be taken in from the opposite side of the support substrate. It is also possible to use a transparent material such as tempered glass for the substrate, configure a cell thereon, and take in light from the transparent support substrate side. Specifically, a module structure called a super straight type, a substrate type, or a potting type, or a module structure such as a substrate integrated type used in an amorphous silicon solar cell or the like is possible. These module structures can be appropriately selected depending on the purpose of use and the place of use (environment). FIG. 4 shows an example in which the element of the present invention is modularized with an integrated substrate.
[0139]
The structure of FIG. 4 has a transparent conductive layer 12 on one surface of a transparent substrate 13, and further a dye-adsorbing TiO on this.₂The cell provided with the layer 10, the solid charge transfer layer 16 and the metal layer 8 is modularized, and the antireflection layer 17 is provided on the other surface of the transparent substrate 13. In this case, in order to increase the utilization efficiency of incident light, the dye adsorbing TiO that is the photosensitive portion₂It is preferable to increase the area ratio of the layer 10 (area ratio when viewed from the transparent substrate 13 side which is the light incident surface).
[0140]
The typical structure of the super straight type and the substrate type is such that cells are arranged at regular intervals between support substrates that are transparent on one or both sides and treated with antireflection, and metal leads or flexible wiring between adjacent cells. Are connected to each other, and a collecting electrode is arranged on the outer edge portion, and the generated electric power is taken out to the outside. Various types of plastic materials such as ethylene vinyl acetate (EVA) can be used between the substrate and the cell in the form of a film or a filled resin depending on the purpose in order to protect the cell and increase the current collection efficiency. In addition, when using it in a place where it is not necessary to cover the surface with a hard material, such as where there is little impact from the outside, the surface protective layer should be composed of a transparent plastic film, or the above filling and sealing material should be cured Thus, it is possible to provide a protective function and eliminate the support substrate on one side. The periphery of the support substrate is fixed in a sandwich shape with a metal frame to seal the inside and secure the rigidity of the module, and the support substrate and the frame are hermetically sealed with a sealing material.
[0141]
In addition, if a flexible material is used for the cell itself, the support substrate, the filler, and the sealing member, a solar cell can be formed on the curved surface. Thus, solar cells having various shapes and functions can be manufactured in accordance with the purpose of use and the environment of use.
[0142]
Super straight type solar cell module, for example, while transporting the front substrate sent out from the substrate supply device with a belt conveyor etc., the cell is placed on it together with the sealing material, inter-cell connection lead wire, back surface sealing material, etc. After sequentially laminating, a back substrate or a back cover can be placed and a frame can be set on the outer edge.
[0143]
On the other hand, in the case of the substrate type, the support substrate sent from the substrate supply device is transported by a belt conveyor, etc., and the cells are sequentially stacked thereon together with inter-cell connection leads, sealing materials, etc. It can be made by placing and setting a frame on the peripheral edge.
[0144]
The module having the structure shown in FIG. 4 includes selective plating, selective etching, CVD, PVD, etc. so that a transparent electrode, a photosensitive layer, a charge transfer layer, a back electrode, and the like are arranged three-dimensionally and at regular intervals on a support substrate. Patterning can be done by semiconductor process technology, pattern coating or wide coating, and then by laser scribing, plasma CVM (described in Solar Energy Materials and Solar Cells, 48, p373-381 etc.) or mechanical methods such as grinding. Thus, a desired module structure can be obtained.
[0145]
Other members and processes will be described in detail below.
Examples of the sealing material include liquid EVA (ethylene vinyl acetate), vinylidene fluoride copolymer and acrylic resin film EVA, and the like, weather resistance, electrical insulation, light collection efficiency, cell protection (resistance) Various materials can be used according to the purpose such as improvement of impact properties.
[0146]
These can be fixed on the cell according to the physical properties of the encapsulant, in film-like materials, heat-adhesion after roll pressurization or heat-adhesion after vacuum pressurization, in liquid or paste-like materials, roll coat, bar There are various methods such as coating, spray coating, and screen printing.
[0147]
Moreover, a transparent filler can be mixed in the sealing material to increase the strength or increase the light transmittance.
[0148]
The space between the outer edge of the module and the frame surrounding the periphery may be sealed using a resin having high weather resistance and moisture resistance.
[0149]
When a flexible material such as PET / PEN is used as the support substrate, a roll-shaped support is drawn out to form a cell thereon, and then a sealing layer can be continuously laminated by the above method. High productivity processes can be built.
[0150]
In order to increase power generation efficiency, the surface of the substrate (generally tempered glass) on the light intake side of the module is subjected to antireflection treatment. This includes a method of laminating an antireflection film and a method of coating an antireflection layer.
[0151]
Moreover, it is possible to increase the utilization efficiency of incident light by processing the surface of the cell by a method such as grooving or texturing.
[0152]
In order to increase power generation efficiency, it is most important to capture light into the module without loss, but it is also important to reflect light that has passed through the photoelectric conversion layer and reached the inside and efficiently returned to the photoelectric conversion layer side. It is. To this end, after mirror-polishing the support substrate surface, a method of depositing or plating Ag, Al, or the like, a method of providing an alloy layer such as Al-Mg or Al-Ti as a reflective layer on the bottom layer of the cell, or There is a method of increasing the reflectance by creating a texture structure in the lowermost layer by annealing.
[0153]
In order to increase the power generation efficiency, it is important to reduce the connection resistance between cells in order to suppress the internal voltage drop.
[0154]
It is common to connect by wire bonding or conductive flexible sheet, but the method that combines the cell fixing function and the electrical connection function using a conductive adhesive tape or conductive adhesive, the conductive hot melt is desired There is a method of applying a pattern to the position.
[0155]
In a solar cell using a flexible support such as a polymer film, the cells are sequentially formed and cut into a desired size by the method described in the description of semiconductor coating while feeding the roll-shaped support, and then the peripheral portion. Can be sealed with a flexible and moisture-proof material. Also, a module structure called “SCAF” described in Solar Energy Materials and Solar Cells, 48, p383-391 may be used.
[0156]
In a solar cell of a flexible support, it can be used by being bonded and fixed to curved glass or the like.
[0157]
【Example】
Hereinafter, the present invention will be specifically described by way of examples. The dyes used in the examples are as shown below.
[0158]
Embedded image
[0159]
1. Preparation of coating solution containing titanium dioxide particles
A titanium dioxide dispersion having a titanium dioxide concentration of 11% by weight was obtained in the same manner as described in Barbe et al., Journal of American Ceramic Society, Vol. 80, p. 3157, except that the autoclave temperature was 230 ° C. The average size of the obtained titanium dioxide particles was about 10 nm.
To this dispersion, 30% by weight of polyethylene glycol (molecular weight: 20,000, manufactured by Wako Pure Chemical Industries, Ltd.) with respect to titanium dioxide was added and mixed to obtain a coating solution.
[0160]
2. Preparation of dye-adsorbed titanium dioxide electrode
Transparent conductive glass coated with tin oxide doped with fluorine (manufactured by Nippon Sheet Glass, surface resistance is about 10Ω / cm²This coating solution is applied to the conductive surface side of the TCO) with a doctor blade to a thickness of 100 μm, dried at 25 ° C. for 30 minutes, cut into 1 cm square, and an electric furnace (Maffle furnace FP-manufactured by Yamato Scientific) 32 type) at 450 ° C. for 30 minutes. Titanium dioxide coating amount is 15g / m²The film thickness was 8 μm.
[0161]
1cm square TiO₂After the coated glass was taken out and cooled, a solution of Dye A (Dye 3 × 10^-FourMolle / liter, solvent: 2-propanol) was immersed for 12 hours at a time. Color-sensitized TiO2 is washed with ethanol and dried naturally in the dark.₂An electrode substrate was obtained. Similarly, using dyes B and C shown in Table 1, TiO sensitized with each dye₂An electrode substrate was obtained. The amount of dye adsorbed is 1m of titanium dioxide coating area.²Approximately 1.3x10 per^-3Mole.
[0162]
3. Production of photoelectrochemical cell
Color-sensitized TiO prepared as described above₂An electrode substrate (1 cm × 1 cm) was overlaid with a platinum-deposited TCO of the same size (plated with TCO with a thickness of 15 nm on TCO) (see FIG. 1). Next, an electrolyte solution (tetrabutylammonium iodide 0.65 mol / liter, iodine 0.05 mol / liter acetonitrile solution) is soaked in the gap between the two glasses using a capillary phenomenon.₂By introducing into the electrode, photoelectrochemical cells 1 to 3 shown in Table 1 were obtained. It was visually confirmed that the battery 1 transmitted yellow light, the battery 2 transmitted reddish purple, and the battery 3 transmitted blue-green light.
[0163]
According to this example, as shown in FIG. 1, the conductive glass 1 (the conductive agent layer 2 is formed on the glass), TiO₂A photoelectrochemical cell in which the layer 3, the dye layer 4, the electrolytic solution 5, the platinum layer 6 and the glass 7 were laminated in this order and sealed with an epoxy-based sealant was produced.
[0164]
4). Measurement of photoelectric conversion wavelength and photoelectric conversion efficiency
Simulated sunlight was generated by passing light from a 500 W xenon lamp (USHIO) through a spectral filter (AM1.5 manufactured by Oriel). The intensity of this light is 100mW / cm²Met.
[0165]
A crocodile clip was connected to the conductive glass and platinum-deposited glass of the above-described photoelectrochemical cell, irradiated with simulated sunlight, and the generated electricity was measured with a current-voltage measuring device (Keutley SMU238 type). Table 1 shows the open-circuit voltage (Voc), short-circuit current density (Jsc), form factor (FF), and conversion efficiency (η) of the photoelectrochemical cell thus determined.
[0166]
[Table 1]
[0167]
5. Combination of photoelectrochemical cells
When the batteries 1 to 3 were connected in parallel and irradiated with simulated sunlight, the obtained short-circuit current was 14 mA.
From the results of the above examples, it is obvious that a solar power generation device that can be used for stained glass or the like can be produced by appropriately arranging the batteries 1 to 3.
[0168]
【The invention's effect】
According to the present invention, it is possible to obtain a photovoltaic power generation apparatus that can be used for a decorative window that is visually comfortable, such as stained glass, and that has excellent conversion efficiency.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of a photoelectrochemical cell produced in an example.
FIG. 2 is a cross-sectional view showing a basic configuration example of a photoelectrochemical cell.
FIG. 3 is a cross-sectional view showing a basic configuration example of a photoelectrochemical cell.
FIG. 4 is a cross-sectional view showing an example of a board-integrated module configuration.
[Explanation of symbols]
1 Conductive glass
2 Conductive agent layer
3 TiO₂layer
4 Dye layer
5 Electrolyte
6 Platinum layer
7 Glass
8 Metal layer
9 Metal lead
10 Dye adsorption TiO₂layer
11 Charge transfer layer
12 Transparent conductive layer
13 Transparent substrate
14 Undercoat layer
15 Support substrate
16 Solid charge transfer layer
17 Antireflection layer

Claims (2)

A photovoltaic power generation apparatus in which at least two types of photovoltaic power generation cells having different visible light absorption characteristics are combined side by side, wherein the photovoltaic power generation cell contains an inorganic semiconductor spectrally sensitized by a spectral sensitizer, The visible light absorption characteristic is derived from the visible light absorption characteristic of the spectral sensitizer, and the spectral sensitizer is a dye represented by the formula (II), the formula (III), the formula (IV), or the formula (V). A solar power generation device characterized by being.
(In the formula, R _b and R _f each represent a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group, and R _{c to} R _e each represent a hydrogen atom or a substituent. R _{b to} R _f are bonded to each other. X ₁₁ and X ₁₂ each represent nitrogen, oxygen, sulfur, selenium, tellurium, n ₁₁ and n ₁₃ each represent an integer of 0 to 2, and n ₁₂ represents 1 to 6 Represents an integer.)
(Wherein, Z _a is nitrogen .R _g representing a non-metallic atomic group necessary for forming a heterocyclic ring is an alkyl group or an aryl group .Q _a compound methine dye represented by formula (III) Represents a methine group or a polymethine group necessary for forming X. X ₁₃ represents a charge-balanced counter ion, and n ₁₄ represents a number of 0 to 10 necessary to neutralize the charge of the molecule.)
(In the formula, Q _b represents an atomic group necessary for completing a 5- or 6-membered nitrogen-containing heterocycle. Z _b is an atom selected from a carbon atom, an oxygen atom, a nitrogen atom, a sulfur atom, and a hydrogen atom. It represents an atomic group necessary for completing a 3- to 9-membered ring constituted by: L ₁ , L ₂ , L ₃ , L ₄ and L ₅ each independently represents a methine which may have a substituent. N ₅₁ represents an integer of 0 to 4 and n ₅₂ is 0 or 1. R ₅ represents a substituent, W ₁ represents a case where a counter ion is required to neutralize the charge. Represents a counter ion. )
(In the formula, D represents an aromatic group having at least four functional groups, and X ₁ and X ₂ each independently represents a sulfur atom, a selenium atom, CR ₆₃ R ₆₄ or CR ₆₅ = CR ₆₆ , wherein R ₆₃ to R ₆₆ is a hydrogen atom or an alkyl group, R ₆₁ and R ₆₂ are each an alkyl group or an aromatic group, and P ₁ and P ₂ are each a group of nonmetallic atoms necessary to independently form a polymethine dye. W ₂ represents a counter ion when a counter ion is necessary to neutralize the charge.)  The solar power generation device according to claim 1, wherein the inorganic semiconductor is titanium oxide.