JP2000228234A - Optoelectronic transducer and optoelctronic chemical battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pigment-sensitivity-enhanced optoelectronic transducer and a optoelectronic chemical battery which are excellent in a optoelectronic transducer characteristic and durability by the use of a simple manufacturing process. SOLUTION: In this optoelectronic transducer that has a conductive supporting body, a semiconductor fine-particle containing layer that has adsorbed pigment applied to the surface of the conductive supporting body, a charge transferring layer and a couple of electrodes, and is enhanced in pigment sensitivity. This optoelectronic transducer is featured in the charge transfer layer containing a gel electrolyte containing a product provided by reacting a polymer having a hydroxyl group and/or a carboxyl group with a compound having at least two or more isocyanate groups, and this optoelectronic chemical battery uses the transducer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a photoelectric conversion element using semiconductor fine particles sensitized with a dye and a photoelectrochemical cell using the same.

[0002]

2. Description of the Related Art Photovoltaic power generation is a single-crystal silicon solar cell,
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 subject to major research and development.
It is necessary to overcome problems such as a long energy payback time. On the other hand, many solar cells using an organic material intended to have a large area and a low price have been proposed so far, but have a problem that conversion efficiency is low and durability is poor.

Under these circumstances, Nature (Vol. 353,
737-740, 1991) and U.S. Pat.No. 4,492,721 disclose a photoelectric conversion element and a solar cell using semiconductor fine particles sensitized with a dye, and materials and manufacturing techniques for producing the same. . The proposed battery is a wet solar battery using a titanium dioxide porous thin film spectrally sensitized by a ruthenium complex as a working electrode. The first advantage of this method is that an inexpensive oxide semiconductor such as titanium dioxide can be used without purification to a high degree of purity, so that an inexpensive photoelectric conversion element can be provided. Since the absorption of the dye is broad, it is possible to convert light in almost all visible wavelength regions into electricity. However, since this element is a wet type solar cell in which an electrical connection with the counter electrode is made by using an electrolyte solution, there is a concern that when used for a long period of time, the photoelectric conversion efficiency will be significantly reduced due to the exhaustion of the electrolyte, or the element will not function as an element. Have been.

In order to prevent the electrolyte solution from being depleted with time in a wet type solar cell, an element using a solid electrolyte is disclosed in International Patent No. 93/20565, and Japanese Patent Application Laid-Open No. 7-288142, Solid State Ioni.
cs 89 (1996) 263 and JP-A 9-27352, a photoelectric conversion element solidified using a crosslinked polyethylene oxide-based polymer solid electrolyte is further described in J. Phys. Chem. 1995, 99, 1701-
In 1703, a photoelectric conversion element solidified using a polyacrylonitrile-based polymer gel electrolyte is proposed. However, as a result of investigation, photoelectric conversion elements using these solid electrolytes have a complicated gel electrolyte manufacturing process,
It has been found that the photoelectric conversion characteristics, particularly the short-circuit current density, are greatly reduced.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a dye-sensitized photoelectric conversion element and a photoelectrochemical cell which are excellent in photoelectric conversion characteristics and durability in a simple manufacturing process.

[0006]

The object of the present invention is achieved by the following items that specify the present invention. (1) a dye-sensitized photoelectric conversion element having a conductive support, a semiconductor fine particle-containing layer coated with a dye coated on the conductive support, a charge transfer layer, and a counter electrode;
A photoelectric conversion element, wherein the charge transfer layer contains a gel electrolyte containing a product obtained by reacting a polymer having a hydroxyl group and / or a carboxyl group with a compound having at least two isocyanate groups. (2) The photoelectric conversion device according to (1), wherein the polymer having a hydroxyl group and / or a carboxyl group is a polymer represented by the following formula (I).

[0007]

Embedded image

[In the formula (I), R ¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. L ¹ represents a divalent linking group, and n represents an integer of 0 or 1. X ¹ represents a monovalent organic group having a hydroxyl group and / or a carboxyl group. A represents a repeating unit derived from a compound containing an ethylenically unsaturated group. k and m each represent the weight composition ratio of each repeating unit, k is 0.5% by weight or more and 80% by weight or less, and m is 20% by weight or more and 99.5% by weight or less. (3) The photoelectric conversion device according to the above (2), wherein the compound from which the repeating unit containing X ¹ of the formula (I) is derived is selected from hydroxyethyl acrylate, hydroxyethyl methacrylate, methacrylic acid, acrylic acid and vinyl alcohol. . (4) The weight fraction of the polymer represented by the formula (I) in all the constituent components of the gel electrolyte before gelation is 0.5% by weight or more.
The photoelectric conversion element according to the above (2) or (3), wherein the content is 0% by weight or less. (5) The photoelectric conversion device according to the above (1), wherein the polymer having a hydroxyl group and / or a carboxyl group is an etherified product or an esterified product of cellulose. (6) The photoelectric conversion device according to the above (5), wherein the weight fraction of the gelled electrolyte of the etherified or esterified cellulose to all the components before gelation is 0.02% by weight or more and 10% by weight or less. (7) The photoelectric conversion device according to any one of the above (1) to (6), wherein the gel electrolyte contains iodine and an iodine salt. (8) The photoelectric conversion device according to any one of (1) to (7), wherein the dye is a ruthenium complex dye or a polymethine dye. (9) The photoelectric conversion device according to any one of (1) to (8), wherein the semiconductor fine particle-containing layer contains titanium dioxide fine particles. (10) The above (1) to-used for solar modules
The photoelectric conversion element according to any one of (9). (11) A photoelectrochemical cell using the photoelectric conversion element according to any one of (1) to (9).

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments. The photoelectric conversion element of the present invention includes a conductive support, a semiconductor film (photosensitive layer) sensitized by a dye provided on the conductive support,
It consists of a charge transfer layer and a counter electrode. The conductive support on which the semiconductor film is provided functions as a working electrode in the photoelectric conversion element. A photoelectrochemical cell that can use this photoelectric conversion element for a battery that works in an external circuit is used. The photosensitive layer is designed according to the purpose, and may have a single-layer structure or a multilayer structure. Light incident on the photosensitive layer excites the dye.
The excited dye has high-energy electrons, which are transferred from the dye to the conduction band of the semiconductor fine particles and reach the conductive support by diffusion. At this time, the dye molecule is in an oxidized form. In a photoelectrochemical cell, the electrons on the conductive support return to the oxidized dye via the counter electrode and the charge transfer layer while working in an external circuit, and the dye is regenerated.
The semiconductor film functions as a negative electrode of this battery. 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 components of each layer, such as the boundary between the charge transfer layer and the counter electrode, may be mutually diffused and mixed.

The charge transfer layer according to the present invention contains a gel electrolyte. The gel electrolyte comprises a polymer having a hydroxyl group and / or a carboxyl group and a compound having two or more isocyanate groups, as described later in detail. It contains those gelled by reaction. Gelation proceeds easily in such a reaction system. In addition, the effect of preventing deterioration of the photoelectric conversion characteristics with the lapse of time is significantly improved as compared with the case where a solution-based electrolyte is used, and even more than when a polymer having no hydroxyl group or carboxyl group is used. Deterioration of the photoelectric conversion characteristics over time is reduced. Further, the photoelectric conversion characteristics are improved as compared with other polymer gel electrolytes such as cross-linked polyethylene oxide.

In the present invention, the semiconductor is a so-called photoreceptor, and plays a role of absorbing light to separate electric charges to generate electrons and holes. In a dye-sensitized semiconductor, light absorption and the resulting generation of electrons and holes mainly occur in the dye, and the semiconductor is responsible for receiving and transmitting the electrons.

As the semiconductor, a so-called compound semiconductor represented by a metal chalcogenide (eg, oxide, sulfide, selenide, etc.) or a compound having a perovskite structure is used in addition to a simple semiconductor such as silicon and germanium. be able to. Preferably as a metal chalcogenide titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium,
Examples include niobium or tantalum oxide, cadmium, zinc, lead, silver, antimony, bismuth sulfide, cadmium, selenide of lead, and telluride of cadmium. Other compound semiconductors include phosphides such as zinc, gallium, indium and cadmium, gallium arsenide, copper-indium-selenide, copper-indium-sulfide and the like.

The compound having a perovskite structure preferably includes strontium titanate, calcium titanate, sodium titanate, barium titanate, and potassium niobate.

More preferably, the semiconductor used in the present invention is specifically Si, TiO ₂ , SnO ₂ , Fe ₂ O ₃ , WO ₃ , Zn
O, Nb ₂ O ₅ , CdS, ZnS, PbS, Bi ₂ S ₃ , CdSe, CdTe, GaP, I
nP, GaAs, CuInS ₂ , and CuInSe ₂ are mentioned. More preferably _{TiO 2, ZnO, SnO 2,} Fe 2 O 3, WO 3, Nb 2 O 5, CdS, Pb
S, CdSe, InP, GaAs, CuInS ₂ , CuInSe ₂ , most preferably TiO ₂ .

The semiconductor used in the present invention may be single crystal or polycrystal. Although a single crystal is preferable as the conversion efficiency, a polycrystal is preferable in terms of manufacturing cost, securing of raw materials, energy payback time, and the like, and a fine particle semiconductor having a nanometer to micrometer size is particularly preferable.

The particle size of these semiconductor fine particles is preferably 5 to 200 nm as primary particles, more preferably 8 to 1 nm, as an average particle size using a diameter when the projected area is converted into a circle.
Preferably it is 00 nm. The average particle size of the semiconductor fine particles (secondary particles) in the dispersion is 0.01 to 10
It is preferably 0 μm.

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 may be 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 improving the light capture rate by scattering incident light.

The method for producing semiconductor fine particles is described in "Sol-Gel Method Science" by Akio Sakuhana, Agne Shofusha (1988), and "Thin Film Coating Technology by Sol-Gel Method" (1995) by Technical Information Association. Tadao Sugimoto, "Synthesis of Monodisperse Particles and Control of Size and Morphology by New Synthetic Gel-Sol Method", Materia, Vol. 35, No. 9, 1012
The gel-sol method described on pages 10 to 1018 (1996) is preferred.

It is also preferred to use a method developed by Degussa to produce an oxide by high-temperature hydrolysis of chloride in an oxyhydrogen flame.

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 preferable, but furthermore, Manabu Kiyono's "Titanium oxide physical properties and applied technology" Gihodo The sulfuric acid method and chlorine method described in Publication (1997) can also be used.

In the case of titanium oxide, among the sol-gel methods described above, in particular, Barb et al., "Journal of American Ceramic Society, Vol. 80, No. 12, No. 3,
Pages 157 to 3171 (1997) ”and“ Chemical Materials ”such as Burnside
Vol. 10, No. 9, pages 2419 to 2425 ".

As the conductive support, a support such as a metal which has conductivity itself, or a glass or plastic support having a conductive agent layer (conductive layer) on the surface can be used. In the latter case, a preferable conductive agent is a metal (for example, platinum, gold, silver, copper, aluminum, rhodium, indium, etc.), carbon, or a conductive metal oxide (indium-tin composite oxide, tin oxide doped with fluorine). And the like). The conductive agent layer preferably has a thickness of about 0.02 to 10 μm.

The lower the surface resistance of the conductive support, the better. The preferred range of the surface resistance is 100 Ω / cm ² or less, and more preferably 40 Ω / cm ² or less. The lower limit is not particularly limited, but is usually about 0.1 Ω / cm ² .

Preferably, the conductive support is substantially transparent. Substantially transparent means that light transmittance is 10%
The above means that it is preferably at least 50%, particularly preferably at least 70%. As the transparent conductive support, glass or plastic coated with a conductive metal oxide is preferable. Among them, 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. In addition, for a low-cost and flexible photoelectric conversion element or photoelectrochemical cell, a transparent polymer film provided with the above conductive layer is preferably used. Transparent polymer films include tetraacetyl cellulose (TAC), polyethylene terephthalate (PE)
T), polyethylene naphthalate (PEN), syndioctatic polysterene (SPS), polyphenylene sulfide (PPS), polycarbonate (PC), polyacrylate (PAr), polysulfone (PSF), polyester sulfone (PES), polyether There are imide (PEI), cyclic polyolefin, brominated phenoxy and the like. When a transparent conductive support is used, it is preferable that light be incident from the support side. In this case, the coating amount of the conductive metal oxide is preferably 0.01 to 100 g per 1 m ² of a glass or plastic support.

Metal leads may be used to reduce the resistance of the transparent conductive substrate. The material of the metal lead is preferably a metal such as aluminum, copper, silver, gold, platinum and nickel,
Particularly, aluminum and silver are preferable. It is preferable that the metal lead is provided on a transparent substrate by vapor deposition, sputtering, or the like, and a transparent conductive layer made of tin oxide doped with fluorine or an ITO film is provided thereon. It is also preferable to provide a metal lead on the transparent conductive layer after providing the transparent conductive layer on a transparent substrate. The decrease in the amount of incident light due to the installation of the metal leads is 1 to 10%, more preferably 1 to 5%.

Examples of the method of applying the semiconductor fine particles on the conductive support include a method of applying a dispersion or colloid solution of the semiconductor fine particles on the conductive support, and the above-mentioned sol-gel method. In consideration of mass production of photoelectric conversion elements, liquid physical properties, and flexibility of a support, a wet film forming method is relatively advantageous. As a wet type film applying method, a coating method and a printing method are typical.

As a method for preparing a dispersion of semiconductor fine particles, in addition to the above-mentioned sol-gel method, a method of grinding in a mortar, a method of dispersing while pulverizing using a mill, or a method of synthesizing a semiconductor in a solvent when synthesizing a semiconductor. A method of precipitating it as fine particles and using it as it is may be mentioned. Examples of the dispersion medium include water and various organic solvents (eg, methanol, ethanol, isopropyl alcohol, dichloromethane, acetone, acetonitrile, ethyl acetate, etc.). When dispersing,
If necessary, a polymer, a surfactant, an acid, a chelating agent or the like may be used as a dispersing aid.

The application method includes a roller method and a dip method as an application system, an air knife method and a blade method as a metering system, and a method in which application and metering can be performed in the same part.
No. 4,589,294, U.S. Pat. No. 2,761,419, and U.S. Pat.
A slide hopper method, an extrusion method, a curtain method and the like described in US Pat. As a general-purpose machine, a spin method or a spray method is also preferably used.

As the wet printing method, three types of printing methods such as relief printing, offset printing and gravure printing, intaglio printing, rubber printing and screen printing have been conventionally preferred.

From the above methods, a preferable film forming method is selected according to the liquid viscosity and the wet thickness.

The liquid viscosity is greatly affected by the type and dispersibility of the semiconductor fine particles, the type of solvent used, and additives such as a surfactant and a binder. High viscosity liquid (for example, 0.01 to 500 Po
In ise), an extrusion method or a casting method is preferable, and in a low-viscosity liquid (for example, 0.1 Poise or less), a slide hopper method, a wire bar method, or a spin method is preferable, and a uniform film can be formed.

In the case of applying a low-viscosity liquid by the extrusion method, the application is possible if the applied amount is a certain amount.

Screen printing is often used for applying a high-viscosity paste of semiconductor fine particles, and this method can also be used.

As described above, a method of applying a wet film may be appropriately selected according to parameters such as the liquid viscosity of the coating liquid, the coating amount, the support, and the coating speed.

Further, the semiconductor fine particle layer need not be limited to a single layer. It is also possible to apply a multi-layer coating of dispersions having different particle diameters of fine particles.Also, it is possible to apply a multi-layer coating of different types of semiconductors or different coating compositions of binders and additives. Even when the film thickness is insufficient, the multilayer coating is effective. The extrusion method or slide hopper method is suitable for multi-layer coating. In the case of multi-layer coating, multiple layers may be coated at the same time,
It may be applied several times to several tens of times sequentially. Furthermore, a screen printing method can also be preferably used in the case of successive coating.

In general, as the thickness of the layer containing semiconductor fine particles increases, the amount of dye carried per unit projected area increases, so that the light trapping rate increases. However, the diffusion distance of generated electrons increases, and the loss due to charge recombination also increases. growing. Therefore, the semiconductor fine particle layer has a preferable thickness, but typically has a thickness of 0.1 to 100 μm. When used as a photoelectrochemical cell, the thickness is preferably 1 to 30 μm,
More preferably, it is 2 to 25 μm. The coating amount per support 1 m ² of the semiconductor fine particles 0.5～400G, more 5~100g is preferred.

The semiconductor fine particles are preferably subjected to a heat treatment in order to bring the particles into electronic contact with each other after being applied to the conductive support, and to improve the strength of the coating film and the adhesion to the support. A preferred range of the heat treatment temperature is 40 ° C. or more and less than 700 ° C.,
It is not less than 00 ° C and not more than 600 ° C. The heat treatment time is 1
It is about 0 minutes to 10 hours. When a support having a low melting point or softening point, such as a polymer film, is used, high-temperature treatment is not preferable because the support is deteriorated. Further, it is preferable that the temperature is as low as possible from the viewpoint of cost. The lowering of the temperature can be achieved by the above-mentioned combination of small semiconductor particles having a size of 5 nm or less, heat treatment in the presence of a mineral acid, and the like.

After the heat treatment, chemical plating using, for example, an aqueous solution of titanium tetrachloride for the purpose of increasing the surface area of the semiconductor particles, increasing the purity in the vicinity of the semiconductor particles, and increasing the efficiency of electron injection from the dye into the semiconductor particles. Alternatively, electrochemical plating using an aqueous solution of titanium trichloride may be performed.

It is preferable that the semiconductor fine particles have a large surface area so that many dyes can be adsorbed. For this reason, the surface area in the state where the semiconductor fine particle layer is coated on the support is preferably at least 10 times, more preferably at least 100 times the projected area. The upper limit is not particularly limited, but is usually about 1000 times.

The dye used in the present invention is preferably a metal complex dye or a polymethine dye. One type of dye may be used, or two or more types may be used in combination. The dye to be mixed can be selected so as to widen the wavelength range of the photoelectric conversion as much as possible or to match the wavelength range of the target light source.
Such a dye preferably has an appropriate interlocking group for the surface of the semiconductor fine particles. Preferred linking groups, COOH groups, SO ₃ H group, a cyano group, -P (O) (OH) 2 group, -OP (O) (OH) 2 group, or, oxime, dioxime, hydroxyquinoline, salicylate and Chelating groups having π conductivity, such as α-keto enolate. Among them, COOH group, -P (O) (OH) ₂
The group, -OP (O) (OH) _2, is particularly preferred. These groups may form a salt with an alkali metal or the like, or may form an intramolecular salt. In the case of a polymethine dye, if the methine chain has an acidic group as in the case of forming a squarylium ring or a croconium ring, this portion may be used as a bonding group.

When the dye used in the present invention is a metal complex dye,
In this case, a ruthenium complex dye is preferable, and further, the following formula (I
The dyes represented by I) are preferred. Formula (II) (Y₁)_pRuB_aB_bB_c In the formula, p is 0 to 2, preferably 2. Ru is
Represents ruthenium. Y ₁Is Cl, SCN, H_TwoO, Br,
Coordination selected from I, CN, NCO, and SeCN
I am a child. B_a, B_b, B_cIs independently the following B-1
Or an organic ligand selected from B-8.

[0042]

Embedded image

[0043]

Embedded image

Here, _Ra is a hydrogen atom, a halogen atom,
A substituted or unsubstituted alkyl group having 1 to 12 carbon atoms (hereinafter referred to as C number), an aralkyl group substituted or unsubstituted with 7 to 12 carbon atoms, or a substituted or unsubstituted with 6 to 12 carbon atoms Represents an aryl group. The above alkyl group,
The alkyl portion of the aralkyl group may be linear or branched, and the aryl portion of the aralkyl group may be monocyclic or polycyclic (condensed ring, ring assembly). .

The ruthenium complex dyes used in the present invention include, for example, US Pat.
Complex dyes described in 5084365, 5350644, 5463057, 5525440 and JP-A-7-249790.

Preferred specific examples of the metal complex dye used in the present invention are shown below, but the present invention is not limited to these.

[0047]

Embedded image

[0048]

Embedded image

[0049]

Embedded image

When the dye used in the present invention is a polymethine dye, a dye represented by the following formula (III) or (IV) is preferred.

[0051]

Embedded image

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
Represents a hydrogen atom or a substituent. R _{b to} R _f may combine with each other to form a ring. X ₁₁ and X ₁₂ each represent nitrogen, oxygen, sulfur, selenium, or tellurium. n ₁₁ and n
₁₃ represents an integer of 0 to 2; n ₁₂ represents an integer of 1 to 6; The compound represented by the formula (III) may have a counter ion depending on the charge of the whole molecule.

The above alkyl group, aryl group and heterocyclic group may have a substituent. The alkyl group may be linear or branched, and the aryl group and the heterocyclic group may be monocyclic or polycyclic (condensed ring, ring assembly). The ring formed by R _{b to} R _f may have a substituent and may be a single ring or a condensed ring.

[0054]

Embedded image

[0055] In the formula, Z _a represents a non-metallic atomic group necessary for forming a nitrogen-containing heterocyclic ring. R _g is an alkyl group or an aryl group. Q represents a methine group or a polymethine group necessary for the compound represented by the formula (IV) to form a methine dye. X ₁₃ represents a charge balancing counter ion, and n ₁₄ represents a number from 0 to 10 required to neutralize the charge of the molecule.

[0056] nitrogen-containing heterocyclic ring formed by the above Z _a may have a substituent, may be a condensed ring may be a single ring. Further, 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 (condensed ring, Ring set).

The dye represented by the formula (IV) has the following formula (IV)
The dyes represented by -a) to (IV-d) are preferable.

[0058]

Embedded image

In the formulas (IV-a) to (IV-d), R ₁₁ to
R ₁₅ , R _{21 to} R ₂₄ , R _{31 to} R ₃₃ , and R _{41 to} R ₄₃ each independently represent a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group, and Y ₁₁ , Y ₁₂ , Y ₂₁ , Y _22, Y ₃₁ ~Y
₃₅ and Y ₄₁ to Y ₄₆ each independently represent oxygen, sulfur, selenium, tellurium, -CR ₁₆ R ₁₇ - represents a -, or -NR _18. R _{16 to} R ₁₈ each independently represent a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group. Y ₂₃ is O ^{-,
S -, Se -, Te -} , or -NR ₁₈ ^- represents a. V _11, V
_{1 2, V 21, V 22} , V 31 and V ₄₁ each independently represents a substituent, n _15, n ₃₁ and n ₄₁ are 1 independently
Represents an integer of 6.

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 a single group. It may be a ring or a polycyclic (condensed ring, ring assembly).

Specific examples of the above polymethine dyes are described in M.
Organic Col by Okawara, T. Kitao, T. Hirasima, M. Matuoka
orants (Elsevier) and others.

Preferred specific examples of the polymethine dye represented by the formula (III) or (IV) are shown below, but the present invention is not limited thereto.

[0063]

Embedded image

[0064]

Embedded image

[0065]

Embedded image

[0066]

Embedded image

[0067]

Embedded image

[0068]

Embedded image

[0069]

Embedded image

[0070]

Embedded image

[0071]

Embedded image

The compounds represented by the formulas (III) and (IV) are described in "Heterocyclic Compounds-Cyanine Soybeans &Co.," by FM Harmer.
Related Compounds (Heterocyclic Compounds-
Cyanine Dyes and Related Compounds), John Wiley & Sons, Inc.- New York, London, 1964, DMSturmer, Heterocyclic Compounds-Special Topics. In Heterocyclic Compounds-Specia
l topics in heterocyclic chemistry), Chapter 18,
Section 14, Sections 482-515, John Willie
John Wiley & Sons, New York, London, 1977, "Rodd's Chemistry of Carbon Compounds"
Carbon Compounds) '' 2nd.Ed.vol.IV, partB, 1977
Published in Chapter 15, Chapters 369-422, Elsevier Science Public Company, Inc.
It can be synthesized based on the method described in Science Publishing Company Inc., New York, UK Patent No. 1,077,611, and the like.

As a method of adsorbing the dye on the semiconductor fine particles, a method of immersing the working electrode containing the semiconductor particles which are well dried in the dye solution or applying the dye solution to the semiconductor fine particle layer and adsorbing the dye can be used. . In the former case, a dipping method, a dipping method, a roller method, an air knife method, or the like can be used. The latter coating method includes a wire bar method, a slide hopper method, an extrusion method, a curtain method, a spin method, and a spray method, and the printing method includes letterpress, offset, gravure, screen printing, and the like.

As in the case of the formation of the semiconductor fine particle layer, the liquid viscosity can be determined by various printing methods other than the extrusion method for a high viscosity liquid (for example, 0.01 to 500 Poise) and the low viscosity liquid (for example, 0.1 Poise or less). A slide hopper method, a wire bar method, or a spin method is suitable, and a uniform film can be obtained.

As described above, the viscosity of the dye coating solution, the coating amount,
An application method may be appropriately selected according to parameters such as a support and a coating speed. The time required for dye adsorption after coating should be as short as possible in consideration of mass production.

Since the presence of unadsorbed dye causes disturbance of device performance, it is preferable to remove the dye by washing immediately after adsorption. It is preferable to perform cleaning with a polar solvent such as acetonitrile and an organic solvent such as an alcohol solvent using a wet cleaning tank. In order to increase the amount of the adsorbed dye, it is preferable to perform the heat treatment before the adsorption. After the heat treatment, in order to avoid adsorption of water on the surface of the semiconductor fine particles, it is also preferable to quickly adsorb the dye at 40 to 80 ° C. without returning to normal temperature.

The amount of the dye used is preferably from 0.01 to 100 mmol per m ² of the support. The amount of the dye adsorbed on the semiconductor fine particles is preferably 0.01 to 1 mmol per 1 g of the semiconductor fine particles.

By using such a dye amount, a sufficient sensitizing effect in a semiconductor can be obtained. In contrast,
If the amount of the dye is small, the sensitizing effect becomes insufficient, and if the amount of the dye is too large, the dye not adhering to the semiconductor floats and causes a reduction in the sensitizing effect.

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).

For the purpose of promoting the removal of excess dye, the surface of the semiconductor fine particles may be treated with an amine after adsorbing the dye. Preferred 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 by dissolving them in an organic solvent.

Next, 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 the oxidized dye with electrons. The charge transfer layer of the present invention is a gel electrolyte in which a liquid in which an electrolyte (a redox couple) is dissolved in an organic solvent is contained in a polymer matrix. The electrolyte used in the present invention is preferably composed of an electrolyte, a solvent, and an additive. The electrolyte of the present invention is a combination of I ₂ and iodide (for iodide, LiI, NaI, KI, Cs
Metal iodides such as I and CaI ₂ , or iodine salts of quaternary ammonium compounds such as tetraalkylammonium iodide, pyridinium iodide, imidazolium iodide and the like; a combination of Br ₂ and bromide (bromide such as LiBr, NaBr, KBr, CsB
r, metal bromides, such as CaBr ₂ or tetraalkylammonium bromide, and bromine salts of quaternary ammonium compounds such as pyridinium bromide), as well as ferrocyanate - ferricyanide or ferrocene - metal complexes such as ferricinium ion, Sulfur compounds such as sodium polysulfide and alkyl thiol-alkyl disulfide, viologen dyes, hydroquinone-quinone and the like can be used. Among them, 4 such as I2 and LiI, pyridinium iodide, imidazolium iodide
An electrolyte combining an iodine salt of a quaternary ammonium compound is preferred. The above-mentioned electrolytes may be used as a mixture.
The electrolyte is EP-718288, WO95 / 18456, J. Electr
ochem. Soc., Vol. 143, No. 10, 3099 (1996), Inorg. Che.
m. A salt in a molten state at room temperature (molten salt) described in 1996, 35, 1168-1178 can also be used. When a molten salt is used as an electrolyte, a solvent need not be used. Examples of preferred electrolytes used in the present invention are listed below, but the present invention is not limited thereto.

[0082]

Embedded image

The preferred electrolyte concentration is 0.1 mol / L or more and 15 mol / L or less, more preferably 0.2 mol / L or more and 10 mol / L or less. Further, when iodine is added to the electrolyte, the preferable concentration of iodine is 0.01 mol / liter or more and 0.5 mol / liter or less.

The solvent used in the electrolyte of the present invention is a compound that can exhibit excellent ionic conductivity by lowering the viscosity and improving the ionic mobility, or increasing the dielectric constant and improving the effective carrier concentration. Desirably. As such a solvent, ethylene carbonate, carbonate compounds such as propylene carbonate, heterocyclic compounds such as 3-methyl-2-oxazolidinone, dioxane, ether compounds such as diethyl ether, ethylene glycol dialkyl ether, propylene glycol dialkyl ether, Chain ethers such as polyethylene glycol dialkyl ether and polypropylene glycol dialkyl ether, methanol, ethanol,
Alcohols such as ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, polyethylene glycol monoalkyl ether, and polypropylene glycol monoalkyl ether; polyhydric alcohols such as ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, and glycerin; acetonitrile; Nitrile compounds such as glutaronitrile, methoxyacetonitrile, propionitrile, and benzonitrile; aprotic polar substances such as dimethyl sulfoxide and sulfolane; and water can be used. Among them, the compounds listed below are preferable in the present invention.

[0085]

Embedded image

The present invention J. Am. Ceram. Soc., 80 (12)
Basic compounds such as tert-butylpyridine and 2-picoline and 2,6-lutidine as described in 3157-3171 (1997) may be added. A preferred concentration range when the basic compound is added is 0.05 mol / L or more and 2 mol / L or less.

The electrolyte of the present invention is obtained by adding a polymer containing a hydroxyl group and / or a carboxyl group and a compound containing at least two isocyanate groups to a solution comprising the above-mentioned electrolyte and a solvent, followed by a crosslinking reaction. Gel electrolyte. As the polymer containing a hydroxyl group and / or a carboxyl group used in the present invention, a polymer represented by the formula (I) or an etherified or esterified product of cellulose is preferable.

[0088]

Embedded image

Here, R ¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Desirable R ¹ is a hydrogen atom or a methyl group. L ¹ represents a divalent linking group.
Preferred L ¹ is -COO- group, -OCO- group, -CONR ² -group, -N
R ³ CO— group, phenylene group, alkylene group (C 1
~ 4), -O- group. Also, a combination of these may be used. R ² and R ³ each represent a hydrogen atom or an alkyl group which may have a substituent having 1 to 4 carbon atoms. R ² and R ³ are each preferably a hydrogen atom or a methyl group. Further, it may be a group represented by X ^1. n represents an integer of 0 or 1. X ¹ represents a monovalent organic group having a hydroxyl group and / or a carboxyl group. The repeating unit containing X ¹ is particularly preferably selected from hydroxyethyl acrylate, hydroxyethyl methacrylate, methacrylic acid, acrylic acid, and vinyl alcohol. A represents a repeating unit derived from a compound having an ethylenically unsaturated group. As the preferred monomers represented by A used in the present invention, esters or amides derived from acrylic acid or α-alkylacrylic acid (for example, methacrylic acid) (for example, N-iso-propyl ( (Meth) acrylamide, N-tert-butyl (meth) acrylamide, (meth) acrylamide, 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth)
Acrylamidopropyltrimethylammonium chloride, N- (meth) acryloyl-N, N-dimethylamine, N- (meth) acryloyl-N, N-diethylamine, N- (meth) acryloylmorpholine, N- (meth) acryloyl-2, 6-dimethylmorpholine, N-
(Meth) acryloylpiperidine, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, cyclohexyl (meth) acrylate, 2 -(2-methoxyethoxy) ethyl (meth) acrylate, etc.), vinyl esters (eg, vinyl acetate), esters derived from maleic acid or fumaric acid (dimethyl maleate,
Dibutyl maleate, diethyl fumarate, etc.), maleic acid, fumaric acid, sodium salt of p-styrenesulfonic acid, acrylonitrile, methacrylonitrile, dienes (eg, butadiene, cyclopentadiene, isoprene), and aromatic vinyl compounds (eg, styrene) , P-chlorostyrene, sodium styrenesulfonate), N-vinylformamide, N-vinyl-N-methylformamide, vinylsulfonic acid, sodium vinylsulfonate,
Examples include vinylidene fluoride, vinylidene chloride, vinyl alkyl ethers (for example, methyl vinyl ether), ethylene, propylene, 1-butene, isobutene, N-phenylmaleimide and the like. k and m represent the weight composition ratio of each repeating unit, and k is 0.5% by weight or more.
80% by weight or less and m is 20% by weight or more and 99.5% by weight or less. More preferably, k is from 1% by weight to 50% by weight, and m is from 50% by weight to 99% by weight.

The polymer represented by the formula (I) is described by Takayuki Otsu and Masayoshi Kinoshita: Experimental Method for Polymer Synthesis (Chemical Doujin) and Takatsu Otsu: Lecture Polymerization Reaction Theory 1 Radical Polymerization (I) (Chemical Doujin) Can be synthesized by radical polymerization, which is a general polymer synthesis method described in (1). The polymer represented by the formula (I) can be synthesized by heating, light, electron beam, or electrochemical radical polymerization, and it is particularly preferable to use radical polymerization by heating. Formula (I)
The polymerization initiator preferably used when the polymer represented by the formula is synthesized by radical polymerization by heating is, for example, 2,2'-azobisisobutyronitrile, 2,2 '
-Azobis (2,4-dimethylvaleronitrile), dimethyl 2,2'-azobis (2-methylpropionate)
Azo initiators such as (dimethyl 2,2'-azobisisobutyrate), and peroxide initiators such as benzoyl peroxide. The preferable addition amount of the polymerization initiator is from 0.01% by weight to 20% by weight, more preferably from 0.1% by weight to 10% by weight, based on the total amount of the monomers.

Examples of the etherified or esterified cellulose preferably used in the present invention include acetylcellulose, acetylbutyrylcellulose, methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, carboxymethylcellulose and benzylcellulose. The number of introduced substituents such as acetyl group is 0.1 per glucose ring.
The number is preferably 2.8 or less and 0.1 or more and 2.5 or less.
More preferably, the number is not more than the number.

The polymer having a hydroxyl group and / or a carboxyl group used in the present invention has a preferable degree of polymerization before gelation of 10 to 1,000,000, more preferably 30 to 1,000,000.
Not less than 800,000, particularly preferably 30 to 600,000
It is as follows.

[0093]

Examples of the polymer having a hydroxyl group and / or a carboxyl group which are preferably used in the gel electrolyte of the present invention are shown below, but the present invention is not limited thereto. x and y indicate weight composition ratios.

[0095]

Embedded image

[0096]

Embedded image

[0097]

Embedded image

In the case of the polymer of the formula (I), the weight fraction of the above-mentioned polymer in the gel electrolyte is not less than 0.5% by weight and not more than 80% by weight based on all components of the electrolyte before gelation. And more preferably 1.5% by weight or more and 50% by weight or less. When the polymer is an etherified product or an esterified product of cellulose, the content is preferably 0.02% by weight or more and 10% by weight or less, and more preferably 0.05% by weight or more and 7% by weight or less. If the amount is reduced, the gel strength is reduced and the liquid is liable to leak. On the other hand, if the amount is increased, the liquid resistance (electric resistance) increases, which is not preferable.

Next, compounds having two or more isocyanate groups will be described. In the present invention, a compound containing at least two isocyanate groups is used as a crosslinking agent. Preferred isocyanate compounds used in the present invention include toluylene diisocyanate (TDI), 2,
4- toluylene diisocyanate dimer, naphthylene
-1,5-diisocyanate (NDI), 0-toluylene diisocyanate, diphenylmethane diisocyanate (MDI), triphenylmethane triisocyanate, tris- (p-isocyanatophenyl) thiophosphite, millionate MR ( Polymethylene polyphenyl isocyanate such as Nippon Polyurethane), polyfunctional aromatic isocyanate such as Sumimodule L, Desmodur IL, aromatic polyisocyanate such as Desmodur VL, polyfunctional aromatic aliphatic isocyanate, Functional aromatic isocyanate,
Hexamethylene diisocyanate (HMDI), trimethylhexamethylene diisocyanate, isophorone diisocyanate, blocked polyfunctional aliphatic isocyanate, fatty acid-modified polyfunctional aliphatic isocyanate, block type polyisocyanate, isocyanate mixture, ether Block-type isocyanate prepolymers containing a group or a urethane group, polymer polyisocyanates, polyisocyanate prepolymers, and xylylene diisocyanate (XDI). Among them, toluylene diisocyanate (TD
I), polymethylene polyphenyl isocyanate such as 0-toluylene diisocyanate, hexamethylene diisocyanate (HMDI), diphenylmethane diisocyanate (MDI), millionate MR (manufactured by Nippon Polyurethane), and isophorone diisocyanate are particularly preferred. .

Examples of compounds having two or more isocyanate groups preferably used in the present invention are shown below, but the present invention is not limited to these.

[0101]

Embedded image

The preferable addition amount of the compound having two or more isocyanate groups is 0.1% by weight or more and 80% by weight or less based on the polymer having a hydroxyl group and / or a carboxyl group. A more preferable addition amount range is 0.3% by weight or more and 50% by weight or less, particularly preferably 0.3% by weight or less.
Not less than 40% by weight.

The gel electrolyte of the present invention can be gelled by the method described in “Crosslinking Agent Handbook” (edited by Hozo Yamashita and Tosuke Kaneko, Taiseisha Publishing). And a solution containing a hydroxyl group and / or a carboxyl group and a compound having at least two isocyanate groups in a solution consisting of a solvent and a solvent.
After about 1 to 8 hours have passed. The gel electrolyte of the present invention may be added with a catalyst such as dibutyl dilauryl tin or heated as needed in order to promote the crosslinking reaction. When the catalyst is added, the preferable addition amount is 0.001% by weight or more and 10% by weight or less based on the compound containing two or more isocyanate groups. The preferred temperature range when heating during gelation is 30 ° C or higher and 15
0 ° C or less.

The gel electrolyte layer can be formed by the following two methods. One is a method in which a counter electrode is first stuck on a semiconductor fine particle layer carrying a sensitizing dye, and a liquid electrolyte solution before gelation is sandwiched in the gap. The other is a method in which a gel electrolyte layer is directly provided on the semiconductor fine particle layer, and a counter electrode is subsequently provided.

As the former method (sandwiching of the gel electrolyte), a normal pressure process utilizing a capillary phenomenon by immersion or the like and a vacuum process of replacing the gas phase with a liquid phase at a pressure lower than normal pressure can be used. In this case, the liquid viscosity before gelation (immediately after liquid preparation) is preferably 1000 cp or less in order to quickly introduce the electrolyte solution before gelation into the device.

In the latter case, the wet electrolyte layer is provided with a counter electrode in an undried state, and measures are taken to prevent the edge portion from leaking liquid. As a method of applying a gel electrolyte,
As well as the application of the semiconductor fine particle layer and the dye, the dipping method, the roller method, the dipping method, the air knife method, the extrusion method, the slide hopper method, the wire bar method, the spin method,
A spray method, a casting method, various printing methods and the like can be considered.
In addition, a mixed solution of an electrolyte, a solvent, and a polymer represented by the formula (I) is applied first, and then a solution of a compound containing two or more isocyanate groups is overcoated to cause gelation. This is also an effective method for mass production, and is preferably used in the present invention.

The water content in the charge transfer layer serving as the gel electrolyte layer is preferably 10,000 ppm or less, more preferably 2,000 ppm or less, and particularly preferably 100 ppm or less.

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 as in the case of the above-described conductive support. However, the support is not necessarily required in a configuration in which the strength and the sealing property are sufficiently maintained. Specifically, as the conductive material used for the counter electrode, a metal (for example, platinum, gold, silver, copper, aluminum, rhodium,
Indium, etc.), carbon, or a conductive metal oxide (indium-tin composite oxide, tin oxide doped with fluorine, or the like). The thickness of the counter electrode is not particularly limited, but is preferably 3 nm or more and 10 μm or less. If it is a metal material, its thickness is preferably 5 μm.
m, more preferably 5 nm or more and 3 μm or less.

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,
It is preferable that the conductive support is transparent and sunlight is 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, as the counter electrode, glass or plastic on which a metal or a conductive oxide is deposited, or a metal thin film can be used.

Further, a layer having other necessary functions such as a protective layer and an antireflection film can be provided on the conductive support or the counter electrode of the working electrode. When such layers are separated in function by multiple layers, simultaneous multilayer coating and sequential coating can be performed, but simultaneous multilayer coating is more preferable in terms of productivity. In the simultaneous multi-layer coating, the slide hopper method and the extrusion method are suitable in consideration of productivity and uniformity of film formation. In addition, these functional layers can be provided by a technique such as vapor deposition or pasting depending on the material.

In the photoelectrochemical cell of the present invention, it is preferable to seal the side surface of the cell with a polymer, an adhesive or the like in order to prevent deterioration of components and volatilization of contents.

Next, a cell structure and a module structure when the photoelectric conversion element of the present invention is applied to a so-called solar cell will be described.

The structure inside the cell of the dye-sensitized solar cell is as follows:
Basically, the structure is as shown in Fig. 1 (described later)
However, various forms are possible according to the purpose as shown in FIG. 2 or FIG. When roughly divided into two, a structure capable of entering light from both sides [FIGS. 2 (a), (d), and FIG. 3 (g)]
And a type that is only possible from one side [FIGS. 2 (b), (c),
3 (e) and (f)].

FIG. 2A shows a dye-adsorbed TiO ₂ layer 10 which is a layer containing dye-adsorbed semiconductor fine particles between transparent conductive layers 12.
And the charge transfer layer 11. FIG.
(B), a metal lead 9 is partially provided on a transparent substrate 13;
Further, a transparent conductive layer 12 is provided, an undercoat layer 14, a dye-adsorbed TiO ₂ layer 10, a charge transfer layer 11 and a metal layer 8 are provided in this order, and a support substrate 15 is further provided.
FIG. 2 (c) shows that a metal layer 8 is further provided on a support substrate 15, a dye-adsorbed TiO ₂ layer 10 is provided via an undercoat layer 14, and a charge transfer layer 11 and a transparent conductive layer 12 are further provided.
This is a structure in which a transparent substrate 13 partially provided with a metal lead 9 is arranged with the metal lead 9 side inside. FIG. 2 (d)
Has a structure in which a metal lead 9 is partially provided on a transparent substrate 13, and an undercoat layer 14, a dye-adsorbed TiO ₂ layer 10, and a charge transfer layer 11 are interposed between a transparent conductive layer 12 and a transparent conductive layer 12. FIG. 3 (e) has a transparent conductive layer 12 on a transparent substrate 13, a dye-adsorbed TiO ₂ layer 10 is provided via an undercoat layer 14, and a charge transfer layer 11 and a metal layer 8 are further provided thereon. This is a structure in which a support substrate 15 is arranged. FIG.
(F) has a metal layer 8 on a support substrate 15, a dye-adsorbed TiO ₂ layer 10 is provided via an undercoat layer 14, a charge transfer layer 11 and a transparent conductive layer 12 are further provided, and a transparent substrate 13 is arranged. FIG. 3 (g) shows a transparent conductive layer 1 between transparent substrates 13 having a transparent conductive layer 12.
2 on the inside, the undercoat layer 14, the dye-adsorbed TiO ₂ layer 1
0 and the charge transfer layer 11 are interposed.

The module structure of the dye-sensitized solar cell of the present invention can have basically the same structure as a conventional solar cell module. In general, a cell is formed on a supporting substrate such as a metal or ceramic, and the cell is covered with a filling resin or a protective glass, etc., so that light can be taken in from the opposite side of the supporting substrate. It is also possible to use a transparent material such as tempered glass for the substrate, form a cell thereon, and take in light from the transparent support substrate side. Specifically, a module structure called a superstrate 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 formed into a module with an integrated substrate.

The structure shown in FIG. 4 has a transparent conductive layer 12 on one surface of a transparent substrate 13, on which a dye-adsorbed Ti
A cell provided with an O ₂ layer 10, a solid charge transfer layer 16 and a metal layer 8 is modularized and comprises a transparent substrate 13.
An anti-reflection layer 17 is provided on the other surface. In this case, in order to increase the utilization efficiency of incident light, it is preferable to increase the area ratio of the dye-adsorbed TiO ₂ layer 10 as the photosensitive portion (the area ratio when viewed from the transparent substrate 13 side which is the light incident surface). preferable.

A typical structure of a superstrate type or a substrate type is that cells are arranged at regular intervals between supporting substrates which are transparent on one or both sides and have been subjected to antireflection treatment, and metal leads or adjacent cells are provided between adjacent cells. They are connected by a flexible wiring or the like, and have a structure in which current collecting electrodes are arranged on the outer edge to take out generated power 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 filling resin, depending on the purpose, in order to protect the cell and increase current collection efficiency. When using in places where it is not necessary to cover the surface with a hard material, such as places where there is little external impact, make the surface protective layer of a transparent plastic film or cure the above-mentioned filling and sealing material. It is also possible to provide a protection function and eliminate the support substrate on one side. The periphery of the support substrate is sealed inside and the rigidity of the module is secured.
It is fixed in a sandwich shape with a metal frame, and the space between the support substrate and the frame is hermetically sealed with a sealing material.

When 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 a curved surface. In this way, solar cells having various shapes and functions according to the purpose of use and environment of use can be manufactured.

[0119] The super straight type solar cell module, for example, conveys the front substrate sent from the substrate supply device by a belt conveyor or the like, and seals the cells thereon with a sealing material, inter-cell connection lead wires, and back surface sealing. After laminating sequentially with materials and the like, a back substrate or a back cover can be placed, and a frame can be set on the outer edge to make it.

On the other hand, in the case of the substrate type, while the support substrate sent out from the substrate supply device is conveyed by a belt conveyor or the like, the cells are sequentially laminated thereon with the lead wires for cell connection, the sealing material, and the like. It can be manufactured by placing a front cover and setting a frame on the periphery.

The module having the structure shown in FIG. 4 is formed by selective plating, selective etching, and CVD so that a transparent electrode, a photosensitive layer, a charge transfer layer, a back electrode, and the like are arranged three-dimensionally at regular intervals on a supporting substrate.・ Laser scribing or plasma CVM (Solar Ener) after semiconductor process technology such as PVD, or pattern application or wide application
gy Materials and Solar Cells, 48, p373-381) or a mechanical method such as grinding or the like, and a desired module structure can be obtained.

Hereinafter, other members and steps will be described in detail. Examples of the sealing material include liquid-state EVA (ethylene vinyl acetate) and EVA in the form of a film of a mixture of vinylidene fluoride copolymer and an acrylic resin. Various materials can be used according to the purpose of improving (impact).

These are fixed on the cell according to the physical properties of the sealing material. For a film-like material, heat contact after roll pressing or heat contact after vacuum pressing, and for a liquid or paste-like material, a roll contact. There are various methods such as coating, bar coating, spray coating, screen printing and the like.

Further, the strength and the light transmittance can be increased by mixing a transparent filler into the sealing material.

The space between the outer edge of the module and the frame surrounding the peripheral edge is preferably sealed with a resin having high weather resistance and moisture resistance.

When a flexible material such as PET or PEN is used as the support substrate, a roll-shaped support is drawn out to form cells thereon, and then the sealing layer is continuously laminated by the above-described method. And a highly productive process can be made.

In order to increase the power generation efficiency, the surface of the substrate (generally tempered glass) on the light intake side of the module is subjected to an anti-reflection treatment. This includes a method of laminating an antireflection film and a method of coating an antireflection layer.

Further, by treating the surface of the cell by a method such as grooving or texturing, it is possible to increase the utilization efficiency of incident light.

In order to increase the power generation efficiency, it is most important that light is taken into the module without loss. However, light that has passed through the photoelectric conversion layer and has reached the inside thereof is reflected and efficiently returned to the photoelectric conversion layer side. It is also important. For this purpose, a method in which a support substrate surface is mirror-polished and then Ag or Al is deposited or plated, a method in which an alloy layer such as Al-Mg or Al-Ti is provided as a reflective layer on the lowermost layer of the cell,
Alternatively, there is a method in which a texture structure is formed in the lowermost layer by annealing to increase the reflectance.

In order to increase the power generation efficiency, it is important to reduce the connection resistance between cells from the viewpoint of suppressing the internal voltage drop.

Although connection is generally made by wire bonding or a conductive flexible sheet, a method of using a conductive pressure-sensitive adhesive tape or a conductive adhesive to combine a cell fixing function and an electric connection function, a conductive hot melt To a desired position.

In the case of a solar cell using a flexible support such as a polymer film, cells are sequentially formed and cut to a desired size by the method described in the description of semiconductor coating while feeding a roll-shaped support. In addition, the periphery can be sealed with a flexible and moisture-proof material to produce a battery body. Also, Solar Energy Materials and S
A module structure called “SCAF” described in olar Cells, 48, p383-391 can also be used.

In the case of a solar cell having a flexible support, it can be further used by bonding it to a curved glass or the like.

[0134]

The present invention will be specifically described below with reference to examples showing comparative examples. Example 1 1. Preparation of titanium dioxide dispersion liquid Titanium dioxide (Nippon Aerosil Co., Ltd.)
Degussa P-25) 15 g, water 45 g, dispersant (Triton X-100, manufactured by Aldrich) 1
g of zirconia beads having a diameter of 0.5 mm (manufactured by Nikkato Co., Ltd.), and dispersed for 2 hours at 1500 rpm using a sand grinder mill (manufactured by Imex). The zirconia beads were removed by filtration from the dispersion. In this case, the average particle size of the titanium dioxide was 2.5 μm. The particle size at this time was measured with a master sizer manufactured by MALVERN.

[0135] 2. Dye-adsorbed TiO ₂ electrode (electrode
Preparation of A) The above dispersion liquid using a glass rod on the conductive surface side of conductive glass coated with fluorine-doped tin oxide (TCO glass-U manufactured by Asahi Glass Co., Ltd. cut into a size of 20 mm × 20 mm). Was applied. At this time, adhesive tape is applied to a part (3 mm from the end) on the conductive surface side as a spacer,
Arrange the glass so that the adhesive tape is
It was applied one by one. After application, the adhesive tape was peeled off and air-dried at room temperature for one day. Next, this glass was placed in an electric furnace (muffle furnace FP-32 manufactured by Yamato Scientific Co., Ltd.) and heated at 450 ° C. for 3 hours.
Bake for 0 minutes. After the glass was taken out and cooled, it was immersed in an ethanol solution of the dye shown in Table 1 (3 × 10 ⁻⁴ mol / l) for 12 hours. The dyed glass is
After being immersed in tert-butylpyridine for 15 minutes, it was washed with ethanol and dried naturally. The thickness of the photosensitive layer thus obtained was 10 μm, and the coating amount of the semiconductor fine particles was 20 g / m ² . The amount of dye adsorption depends on the type of dye,
It was appropriately selected from the range of 0.1 to 10 mmol / m ² . In addition,
The surface resistance of the conductive glass was about 30 Ω / cm ² .

[0136]

[Table 1]

[0137] 3. Preparation of Photoelectrochemical Cell The sensitized TiO ₂ electrode substrate (2 cm × 2 cm) prepared as described above was overlaid on a platinum-deposited glass of the same size (see FIG. 1). Next, an electrolytic solution (organic solvent, polymer, polyfunctional isocyanate compound shown in Table 1 and a supporting electrolyte 0.1) is used in the gap between both glasses by utilizing the capillary phenomenon.
65 mol / l, iodine 0.05 mol / l) and introduced into the TiO ₂ electrode,
A photoelectrochemical cell (sample) was obtained. This step was performed by changing the combination of the dye and the electrolyte composition as shown in Table 1. The gelation of the electrolytic solution was performed at room temperature (2
(Temperature of about 5 ° C.) for about 6 hours.

According to the present embodiment, as shown in FIG. 1, charge transfer consisting of conductive glass 1 (a conductive agent layer 2 is provided on glass), TiO ₂ electrode 3, dye layer 4, and gel electrolyte A photoelectrochemical cell in which the layer 5, the platinum layer 6, and the glass 7 were sequentially laminated was produced.

[0139] 4. Measurement of Photoelectric Conversion Efficiency Simulated sunlight containing no ultraviolet light was generated by passing 500 W xenon lamp (Ushio) light through a spectral filter (Oriel AM1.5) and a sharp cut filter (Kenko L-42). . The intensity of this light was 86 mW / cm ² .

An alligator clip was connected to each of the conductive glass and the platinum-deposited glass of the above-mentioned photoelectrochemical cell, simulated sunlight was irradiated, and the generated electricity was measured with a current / voltage measuring device (Keisley SMU238 type). did. The open-circuit voltage (V _oc ), short-circuit current density (J _sc ), form factor (FF), conversion efficiency (η), and
Table 2 shows the short-circuit current density and the decrease rate of the short-circuit current density after continuous irradiation for 0 hours.

[Comparative Example 1] Comparative photoelectrochemical cell A The color-sensitized TiO ₂ electrode substrate (electrode A; 2 cm x 2 cm) prepared in the above-described example was coated with platinum-deposited glass of the same size. They were superimposed (see FIG. 1). Next, an electrolytic solution (0.05 mol / l of iodine using a mixture of acetonitrile and 3-methyl-2-oxazolidinone at a volume ratio of 90:10 as a solvent, lithium iodide 0 (A solution of 0.5 mol / l) to make a comparative photoelectrochemical cell A.

Comparative Example 2 Comparative Photoelectrochemical Battery B A TiO ₂ electrode substrate (electrode
A; 2 cm x 2 cm) on a hexaethylene glycol methacrylate (manufactured by NOF Chemical Co., Ltd.)
1 g of Blenmer PE350) and 100 mg of tetraethylene glycol diacrylate, and 3 g of propylene carbonate as a solvent capable of dissolving the electrolyte
And, as a polymerization initiator, 2-hydroxy-2-methyl-
Lithium iodide (500 mg) was dissolved in a mixed solution containing 20 mg of 1-phenyl-propan-1-one (Darocur 1173, manufactured by Nippon Ciba Geigy Co., Ltd.). Was applied. Next, the porous material to which the above-mentioned mixed solution was applied was placed under reduced pressure to remove bubbles in the porous material to promote penetration of the monomer, and then polymerized by irradiation with ultraviolet light. The device thus obtained was exposed to an iodine atmosphere for 30 minutes to obtain a photoelectrochemical battery B for comparison.

[0143]Comparative Example 3 Comparative Photoelectrochemical Battery C TiO sensitized in the same manner as in the previous example_TwoElectrode substrate (electrode
A; 2cm x 2cm) is platinum-evaporated glass of the same size
And superimposed. Next, a capillary phenomenon is created in the gap between the two glasses.
Using electrolyte (P-1 described in sample No. 1 in Table 1)
The above-mentioned polymer is changed to a polymer having the following structure:
x and y are impregnated with TiO. _TwoIn the electrode
And a photoelectrochemical cell was obtained.

[0144]

Embedded image

With respect to these comparative batteries, the same measurement as in the above example was performed to determine the rate of decrease in short circuit current density and the like. The results are shown in Table 2.

[0146]

[Table 2]

In the examples of the present invention as compared with the comparative example, a photoelectrochemical cell containing a gel electrolyte can be easily produced without the need for heating or degassing, and the photoelectrochemical cell as compared with a wet type photoelectrochemical cell was obtained. It is clear that the conversion characteristics have little deterioration over time.

[0148]

Industrial Applicability According to the present invention, a photoelectric conversion element and a photoelectrochemical cell having a simple manufacturing process, excellent photoelectric conversion characteristics, and less leakage of the electrolyte and accompanying deterioration of the characteristics with time are obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a photoelectrochemical cell prepared 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 illustrating a basic configuration example of a photoelectrochemical cell.

FIG. 4 is a cross-sectional view showing an example of a module configuration of a substrate integrated type.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 conductive glass 2 conductive agent layer 3 TiO ₂ layer 4 dye layer 5 charge transfer layer 6 platinum layer 7 glass 8 metal layer 9 metal lead 10 dye adsorption TiO ₂ layer 11 charge transfer layer 12 transparent conductive layer 13 transparent substrate 14 undercoat layer 15 Support substrate 16 Charge transfer layer 17 Anti-reflection layer

Claims (11)

[Claims] 1. A dye-sensitized photoelectric conversion device having a conductive support, a layer containing semiconductor fine particles adsorbed with a dye coated on the conductive support, a charge transfer layer, and a counter electrode, wherein the charge transfer A photoelectric conversion element, characterized in that the layer contains a gel electrolyte containing a product obtained by reacting a polymer having a hydroxyl group and / or a carboxyl group with a compound having at least two isocyanate groups. 2. The photoelectric conversion device according to claim 1, wherein the polymer having a hydroxyl group and / or a carboxyl group is a polymer represented by the following formula (I). Embedded image [In the formula (I), R ¹ is a hydrogen atom or a group having 1 to 4 carbon atoms.
Represents up to alkyl groups. L ¹ represents a divalent linking group, and n represents an integer of 0 or 1. X ¹ represents a monovalent organic group having a hydroxyl group and / or a carboxyl group. A
Represents a repeating unit derived from a compound containing an ethylenically unsaturated group. k and m each represent a weight composition ratio of each repeating unit, and k is 0.5% by weight or more and 80% by weight.
Hereinafter, m is not less than 20% by weight and not more than 99.5% by weight. ] 3. The photoelectric conversion device according to claim 2, wherein the compound from which the repeating unit containing X ¹ of the formula (I) is derived is selected from hydroxyethyl acrylate, hydroxyethyl methacrylate, methacrylic acid, acrylic acid and vinyl alcohol. . 4. The photoelectric conversion device according to claim 2, wherein the weight fraction of the polymer represented by the formula (I) in all the constituent components of the gel electrolyte before gelation is 0.5% by weight or more and 80% by weight or less. . 5. The photoelectric conversion device according to claim 1, wherein the polymer having a hydroxyl group and / or a carboxyl group is an etherified product or an esterified product of cellulose. 6. The photoelectric conversion device according to claim 5, wherein a weight fraction of the gelled electrolyte of the etherified product or the esterified product of cellulose in all the constituent components before gelation is 0.02% by weight or more and 10% by weight or less. 7. The photoelectric conversion device according to claim 1, wherein the gel electrolyte contains iodine and an iodine salt. 8. The photoelectric conversion device according to claim 1, wherein the dye is a ruthenium complex dye or a polymethine dye. 9. The photoelectric conversion device according to claim 1, wherein said semiconductor fine particle-containing layer contains titanium dioxide fine particles. 10. The photoelectric conversion element according to claim 1, which is used for a solar module. 11. A photoelectrochemical cell using the photoelectric conversion element according to claim 1.