JP2003217692A - Manufacturing method for photoelectric converter, photoelectric converter and photocell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a photoelectric converter showing excellent converting efficiency, a photoelectric converter manufactured by the method, and a photocell using the photoelectric converter. <P>SOLUTION: This manufacturing method for the photoelectric converter having a photosensitive layer containing semiconductor fine particles where a coloring matter is adsorbed, and a conductive support is characterized in that the semiconductor fine particles are treated with polysaccharide. Preferably a 1-polysaccharide is cyclodextrin. Especially it is preferable that a 3-polysaccharide is a compound obtained by mixing α, β or γ-cyclodextrin and a compound expressed by the general formula I at mol ratio of 50:1 to 1:50. MX<SB>n</SB>...(I), wherein M is an element belonging to one of the third to sixth group and the twelfth to fifteenth group of the periodic system, and preferably Ti, Zr, Hf, Ge or Sn. X is a hologen or alkoxy group, and n is integers of 2 to 6. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a photoelectric conversion element using semiconductor fine particles sensitized with a dye, a photoelectric conversion element produced by this method, and a photovoltaic cell using this photoelectric conversion element. It relates to compounds preferably used in the method.

[0002]

2. Description of the Related Art Photoelectric conversion elements are used in various optical sensors, copying machines, photovoltaic devices, and the like. Photoelectric conversion elements include those using metals, those using semiconductors, those using organic pigments or dyes, those using these in combination, and various methods have been put to practical use.

US Pat. Nos. 4,927,721, 4,884,537, and 5084.
365, 5350644, 5463057, 5525440, WO98
/ 50393, JP-A-7-249790 and JP-A-10-504521, a photoelectric conversion element using semiconductor fine particles sensitized by a dye (hereinafter, referred to as "dye-sensitized photoelectric conversion element") and this Materials and manufacturing techniques for making the are disclosed. The advantage of the dye-sensitized photoelectric conversion element is that an inexpensive oxide semiconductor such as titanium dioxide can be used without purification to a high degree of purity and thus can be manufactured at a relatively low cost. However, such a photoelectric conversion element does not always have sufficiently high conversion efficiency, and improvement in conversion efficiency is required. Further, US Pat. No. 5,525,440 describes that conversion efficiency is improved by treating semiconductor particles with an aqueous solution of titanium tetrachloride to form new TiO ₂ particles on the surface of the semiconductor particles. Even the conversion element does not always have sufficiently high conversion efficiency, and further improvement in conversion efficiency has been desired.

[0004]

An object of the present invention is to provide a method for producing a dye-sensitized photoelectric conversion element exhibiting excellent conversion efficiency, a photoelectric conversion element produced by this method, and a photovoltaic cell using the same.
And to provide a novel compound which can be preferably used in the method.

[0005]

As a result of earnest research in view of the above object, the present inventors have found that the conversion efficiency can be improved by treating the semiconductor fine particles used in the photosensitive layer of the dye-sensitized photoelectric conversion element with a polysaccharide. The heading was conceived of the present invention.

That is, the method for producing a photoelectric conversion element of the present invention is a method for producing a photoelectric conversion element having a photosensitive layer containing a semiconductor fine particle having a dye adsorbed thereon and a conductive support. It is characterized in that it is treated with sugar.

The photoelectric conversion element of the present invention is manufactured by the method of the present invention, and the photovoltaic cell of the present invention uses the photoelectric conversion element.

The photoelectric conversion device and the photovoltaic cell of the present invention exhibit further excellent conversion efficiency by satisfying the following preferable conditions. (1) The polysaccharide is preferably a cyclodextrin. (2) The polysaccharide preferably contains an element belonging to any one of Groups 3 to 6 and Groups 12 to 15 of the Periodic Table, and more preferably contains titanium, zirconium, hafnium, germanium or tin. (3) The polysaccharide is particularly a compound obtained by mixing α, β or γ-cyclodextrin and a compound represented by the following general formula (I) in a molar ratio of 50: 1 to 1:50. preferable. MX _n (I) In the general formula (I), M represents an element belonging to any of Groups 3 to 6 and Groups 12 to 15 of the Periodic Table, preferably titanium, zirconium, hafnium or germanium. Or represents tin. X represents a halogen or an alkoxy group, and n represents an integer of 2-6. (4) It is preferable to adsorb a dye on the semiconductor fine particles after treating the semiconductor fine particles with the polysaccharide. Further, in this case, it is preferable that the semiconductor fine particles are treated with an aqueous solution of titanium tetrachloride after the treatment with the polysaccharide and before the dye is adsorbed. (5) The dye is particularly preferably a ruthenium complex dye.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The manufacturing method of the present invention is a method for manufacturing a photoelectric conversion element having a photosensitive layer and a conductive support. The photosensitive layer contains semiconductor fine particles to which a dye is adsorbed.
In the production method of the present invention, the conversion efficiency of the photoelectric conversion element is improved by treating the semiconductor fine particles with the polysaccharide described below. The photoelectric conversion element of the present invention is characterized by being manufactured by this method, and the photovoltaic cell of the present invention uses the photoelectric conversion element. Hereinafter, the polysaccharide used in the present invention, the treatment method using the same, and the photoelectric conversion element and photovoltaic cell of the present invention will be described in detail.

[I] Polysaccharide The polysaccharide used in the present invention is a compound having a skeleton in which two or more monosaccharides are linked. The type of monosaccharide (glucose, galactose, mannose, etc.), optical purity (D-form) And L
The ratio of the body) and the specification of the connection (α-glycoside bond, β-glycoside bond, bond via a divalent or higher valent connecting group, etc.) are not limited. The polysaccharide may have a substituent, for example, the hydroxyl group of the sugar may be protected by a protecting group (eg, acetyl group, methyl group, hydroxyethyl group, etc.).

Examples of polysaccharides preferably used in the present invention include linear or cyclic polysaccharides (starches, cyclodextrins, etc.) in which three or more D-glucoses are α-glycosidically linked, and three or more D -Polysaccharides in which glucose is β-glycoside-bonded (cellulose, hydroxyethyl cellulose, etc.), Polysaccharides in which these are linked via a linking group (poly-β-cyclodextrin, etc. in which β-cyclodextrin is crosslinked with epichlorohydrin) Etc. Of these, cyclodextrins are particularly preferable.

Polysaccharides are elements belonging to any of Groups 3 to 6 of the Periodic Table (scandium, yttrium, lanthanoids, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, etc.). Alternatively, it preferably contains an element belonging to any of Groups 12 to 15 (zinc, aluminum, gallium, indium, germanium, tin, antimony, bismuth, etc.), and more preferably contains titanium, zirconium, hafnium, germanium or tin. preferable.

As a particularly preferred embodiment of the polysaccharide containing an element belonging to any of the above Groups 3 to 6 and Groups 12 to 15, α, β or γ-cyclodextrin and the following general formula (I The compound obtained by mixing the compound represented by the above) at a molar ratio of 50: 1 to 1:50. The α, β or γ-cyclodextrin may have a substituent. Hereinafter, the compound represented by the general formula (I) is referred to as "compound (I)". MX _n ... (I)

In the general formula (I), M is an element (scandium, yttrium, etc.) belonging to any of Groups 3 to 6 of the periodic table.
Lanthanides, titanium, zirconium, hafnium,
Vanadium, niobium, tantalum, chromium, molybdenum,
Tungsten etc.) or an element belonging to any of Groups 12 to 15 (zinc, aluminum, gallium, indium, germanium, tin, antimony, bismuth etc.), preferably titanium, zirconium, hafnium, germanium or tin. X is halogen (F, Cl, Br,
I or the like) or an alkoxy group (a methoxy group, an ethoxy group, an isopropoxy group, a butoxy group or the like), and an alkoxy group is preferable. n represents an integer of 2 to 6, and is determined according to the valence of M.

The molar ratio (cyclodextrin: compound (I)) in mixing α, β or γ-cyclodextrin with compound (I) is 50: 1 to 1:50, preferably 1:10.
˜2: 1, more preferably 1: 5 to 1: 1. Cyclodextrin and compound (I), usually 15-250 ℃
The desired polysaccharide can be obtained by mixing for 5 minutes to 24 hours, preferably at 50 to 120 ° C. for 30 to 180 minutes.

The compound obtained by mixing cyclodextrin and compound (I) may have a structure in which cyclodextrin is crosslinked with the element represented by M in the general formula (I). More specifically, it may have a structure in which a hydroxyl group of cyclodextrin and an element represented by M in the general formula (I) are bonded to each other and at least two or more cyclodextrins are crosslinked. For example,
As an example of the compound obtained by mixing β-cyclodextrin and titanium tetraethoxide at a ratio of 1: 1 is a compound having the structure shown below. The position of the hydroxyl group to which the titanium element is bonded, titanium per cyclodextrin molecule The number of element substitutions, the number of cross-linked cyclodextrins, etc. are not limited.

[Chemical 1]

The compound obtained by mixing the cyclodextrin and the compound (I) may be used alone or in combination. As a preferred specific example of this compound, cyclodextrin and compound (I) shown in Table 1 below are prepared as shown in Table 1.
Compounds (1) to (22) obtained by mixing at the molar ratio shown in (cyclodextrin: compound (I)) can be mentioned.

[0018]

[Table 1]

[II] Treatment Method “Treatment” in the present invention means an operation of bringing the semiconductor fine particles into contact with the above-mentioned polysaccharide for a certain period of time before installing the charge transport layer. After the contact, the polysaccharide may or may not be adsorbed on the semiconductor fine particles.

The treatment may be carried out in any state in the process of producing the photoelectric conversion element, but it is preferably carried out after the semiconductor fine particle layer is formed. The order of the dye adsorption step to the semiconductor fine particle layer and the treatment step with the polysaccharide is as follows: (A) a method of performing treatment before adsorption of the dye (hereinafter, referred to as “pretreatment method”) Method of processing after adsorption (hereinafter,
(Hereinafter referred to as "post-treatment method") and (C) a method of performing treatment simultaneously with adsorption of dye (hereinafter referred to as "simultaneous treatment method"). Among them, the pretreatment method is preferable. You may process continuously by combining some of these 3 types of processing methods. When the treatments are carried out continuously, the polysaccharides used in each treatment may be the same or different. Hereinafter, each processing method will be described in detail.

(A) Pretreatment Method In the pretreatment method, the polysaccharide is preferably used after being dissolved or dispersed in a solvent, but when the polysaccharide itself is a liquid, it may be used without a solvent. Hereinafter, a solution in which a polysaccharide is dissolved in a solvent is referred to as a treatment solution, and a dispersion liquid in which the polysaccharide is dispersed in a solvent is referred to as a treatment dispersion liquid. The pretreatment is more preferably carried out using a treatment solution, and the solvent used for the treatment solution may be water, an aqueous solution, an organic solvent or the like, but is preferably an aqueous solution. This aqueous solution is preferably acidic, and for example, hydrogen chloride water, nitric acid aqueous solution, acetic acid aqueous solution, trifluoroacetic acid aqueous solution, dilute sulfuric acid aqueous solution, paratoluenesulfonic acid aqueous solution and the like are preferable.

When pretreatment is performed using a treatment solution or a treatment dispersion (hereinafter, both solutions are collectively referred to as a treatment liquid), a method of immersing the semiconductor fine particle layer in the treatment liquid (hereinafter referred to as an immersion treatment method) Is preferred. Further, a method of spraying the treatment liquid in a spray shape for a certain period of time (hereinafter referred to as a spray method) can also be applied. When performing the dipping treatment method, the temperature of the treatment liquid and the dipping treatment time may be arbitrarily set, but the temperature of the treatment liquid is preferably 5 to 80 ° C, more preferably 5 to 25 ° C, and the dipping treatment time is It is preferably 30 seconds to 24 hours. It is preferable to wash the semiconductor fine particle layer with a solvent after the immersion treatment. For washing, it is preferable to use the same solvent as that used for the treatment liquid or water.

The concentration of the polysaccharide in the treatment solution used in the pretreatment method is preferably 1 × 10 ^{-5 to 2} mol / l, more preferably 1 × 10 ^{-4 to} 5 × 10 ^-1 mol / l. is there.

Polysaccharides are groups 3-6 and 12- of the Periodic Table
When an element belonging to any one of Group 15 is included, it is preferable that the pretreated semiconductor fine particles be fired to form an oxide of these elements on the semiconductor fine particles. The firing temperature is preferably 450 to 550 ° C., and the firing time is preferably 5 minutes to 3 hours.

The semiconductor fine particle layer after the pretreatment may be retreated with a solution of titanium tetrachloride, a polysaccharide or the like. In particular, it is preferable to treat the semiconductor fine particles with an aqueous solution of titanium tetrachloride after pretreatment and before adsorbing the dye. Even after the retreatment, it is preferable to perform the baking as described above to form the metal oxide on the semiconductor fine particles.

(B) Post-treatment method Also in the post-treatment method, as in the case of the pre-treatment method, it is preferable to use a treatment solution or a treatment dispersion liquid, and more preferable to use a treatment solution. When the polysaccharide itself is liquid, it may be used without solvent. The solvent used for the treatment solution may be water, an aqueous solution, an organic solvent or the like, but is preferably an organic solvent.

When an organic solvent is used, it can be appropriately selected depending on the solubility of the polysaccharide. For example, alcohols (methanol, ethanol, t-butanol, benzyl alcohol, etc.), nitriles (acetonitrile, propionitrile, 3-methoxypropionitrile, etc.), nitromethane,
Halogenated hydrocarbons (dichloromethane, dichloroethane, chloroform, chlorobenzene, etc.), ethers (diethyl ether, tetrahydrofuran, etc.), dimethyl sulfoxide, amides (N, N-dimethylformamide, N, N-dimethylacetamide, etc.), N -Methylpyrrolidone, 1,3-dimethylimidazolidinone, 3-methyloxazolidinone, esters (ethyl acetate, butyl acetate, etc.),
Carbonates (diethyl carbonate, ethylene carbonate, propylene carbonate, etc.), ketones (acetone, 2-butanone, cyclohexanone, etc.), hydrocarbons (hexane, petroleum ether, benzene, toluene, etc.), mixed solvents of these are used. it can. Of these, alcohols are preferable.

As in the case of the pretreatment method, the dipping treatment method using the treatment liquid or the spray method can be preferably applied to the posttreatment method. When performing the immersion treatment method, the temperature of the treatment liquid and the immersion treatment time may be arbitrarily set, but the temperature of the treatment liquid is preferably 20 to 80 ° C., and the immersion treatment time is preferably 30 seconds to 24 hours. is there. It is preferable to wash the semiconductor fine particle layer with a solvent after the immersion treatment. For washing, it is preferable to use the same solvent as that used for the treatment liquid.

The concentration of the polysaccharide in the treatment liquid used in the post-treatment method is preferably 1 × 10 ^{-6 to 2} mol / l, more preferably 1 × 10 ^{-5 to} 5 × 10 ^-1 mol / l. is there.

In addition to the polysaccharide, the post-treatment liquid may optionally contain other substances as additives. Examples of preferable additives include surfactants (steroids, polyether compounds, etc.), bases, ureide compounds, silyl compounds and the like. These may be used alone or in combination. The base added to the treatment solution has a conjugate acid pKa of 3 to 8 (tetrahydrofuran: water = 1: 1, 25
C.) is preferred, and examples thereof include pyridine compounds (4-t-butylpyridine, 4-methoxypyridine, etc.). In addition, specific examples of the ureido compound and the silyl compound include compounds (II-1) to (II-13) shown below, and among them, a ureido compound ((II-6) and a silyl group substituted (II-6) and (II-7) and the like) are more preferable. The concentration of these additives in the treatment liquid is preferably 1 × 10 ^{−6 to 2} mol / l, more preferably 1 × 10 ^{−5 to} 5 × 10 ⁻¹ mol / l.

[0031]

[Chemical 2]

(C) Simultaneous Treatment Method In the simultaneous treatment method, it is preferable to use a treatment liquid obtained by dissolving or dispersing a polysaccharide in a dye solution (dye adsorbing liquid) used for adsorbing a dye. Therefore, the solvent used for the treatment liquid is preferably the same as the organic solvent preferably used for the dye adsorption liquid described later. The concentration of the polysaccharide in the treatment liquid is preferably 1 × 10 ^{-6 to 2} mol / l
And more preferably 1 × 10 ^{−5 to} 5 × 10 ⁻¹ mol / l.

Also in the simultaneous treatment method, the dipping treatment method using the treatment liquid can be preferably applied. When performing the immersion treatment method,
Although the temperature of the treatment liquid and the immersion treatment time may be set arbitrarily,
The temperature of the treatment liquid is preferably 20 to 50 ° C., and the immersion treatment time is preferably 5 minutes to 24 hours. It is preferable to wash the semiconductor fine particle layer with a solvent after the immersion treatment. For washing, it is preferable to use the same solvent as that used for the treatment liquid.

The treatment liquid used in the simultaneous treatment method may appropriately contain substances other than these in addition to the polysaccharide and the dye as additives. For example, in order to reduce interaction such as aggregation between dyes, a colorless compound having a surface active property may be added to the treatment liquid and co-adsorbed on the semiconductor fine particles. Such a colorless compound will be described in detail in the section of “(5) Additive to dye adsorbing liquid”.

[III] Photoelectric Conversion Element The photoelectric conversion element of the present invention is preferably formed by laminating a conductive layer 10, a photosensitive layer 20, a charge transport layer 30 and a counter electrode conductive layer 40 in this order as shown in FIG. The photosensitive layer (20) is composed of semiconductor fine particles (21) sensitized with a dye (22) and a charge transport material (23) that has penetrated into the spaces between the semiconductor fine particles (21). The charge transport material 23 in the photosensitive layer 20 is usually the same material used for the charge transport layer 30. An undercoat layer 60 is provided between the conductive layer 10 and the photosensitive layer 20.
May be provided. Further, a substrate 50 may be provided as a base of the conductive layer 10 and / or the counter conductive layer 40 in order to impart strength to the photoelectric conversion element. In the present invention, the layer composed of the conductive layer 10 and the substrate 50 optionally provided is referred to as a “conductive support”, and the layer composed of the counter electrode conductive layer 40 and the substrate 50 optionally provided is referred to as a “counter electrode”. The conductive layer 10, the counter conductive layer 40, and the substrate 50 in FIG.
May be the transparent conductive layer 10a, the transparent counter electrode conductive layer 40a, and the transparent substrate 50a, respectively. A photocell is a device in which such a photoelectric conversion element is connected to an external load in order to perform electric work (power generation), and a photosensor is a device made for the purpose of sensing optical information. Among photovoltaic cells, those in which the charge transport material is mainly composed of an ion transport material are called photoelectrochemical cells, and those whose main purpose is power generation by sunlight are called solar cells.

In the photoelectric conversion element shown in FIG. 1, when the semiconductor fine particles are n-type, the light incident on the photosensitive layer 20 containing the semiconductor fine particles 21 sensitized by the dye 22 excites the dye 22 and the like. High-energy electrons in the dye 22 and the like are passed to the conduction band of the semiconductor fine particles 21, and further diffuse to reach the conductive layer 10. At this time, the dye 22 is an oxidant. In the photovoltaic cell, the electrons in the conductive layer 10 return to the oxidant of the dye 22 via the counter conductive layer 40 and the charge transport layer 30 while working in the external circuit, and the dye 22 is regenerated. The photosensitive layer 20 functions as a negative electrode (photoanode), and the counter conductive layer 40 functions as a positive electrode.
At the boundary of each layer (for example, the boundary between the conductive layer 10 and the photosensitive layer 20, the boundary between the photosensitive layer 20 and the charge transport layer 30, the boundary between the charge transport layer 30 and the counter conductive layer 40, etc.), the constituent components of each layer They may be diffusively mixed with each other. Each layer will be described in detail below.

(A) Conductive Support The conductive support is composed of (1) a single layer of a conductive layer or (2) a conductive layer and a substrate. In the case of (1), as the material of the conductive layer,
Use a conductive layer that can sufficiently maintain the strength and hermeticity of the conductive layer (for example, a metal material such as platinum, gold, silver, copper, zinc, titanium, aluminum, or an alloy containing these). be able to. In the case of (2), a substrate having a conductive layer containing a conductive agent on the photosensitive layer side can be used as a conductive support. Examples of preferable conductive agents include metals (platinum, gold, silver, copper, zinc, titanium, aluminum,
Indium, alloys containing these, and carbon and conductive metal oxides (indium-tin composite oxide, tin oxide doped with fluorine or antimony, etc.). The thickness of the conductive layer is preferably about 0.02 to 10 μm.

The lower the surface resistance of the conductive support, the better. This surface resistance is preferably 50 Ω / □ or less, more preferably 20 Ω / □ or less.

When light is irradiated from the side of the conductive support, the conductive support is preferably substantially transparent.
Substantially transparent means visible to near infrared region (400 to 120
It means that the light transmittance is 10% or more in a part or the whole area of the light of 0 nm). This transmission is preferably 50%
More preferably, it is 80% or more. In particular, it is preferable that the light-transmitting layer has a high transmittance for light in a wavelength range in which the photosensitive layer has sensitivity.

As the transparent conductive support, one having a transparent conductive layer made of a conductive metal oxide formed on the surface of a transparent substrate made of glass, plastic or the like by coating, vapor deposition or the like can be preferably used. Examples of preferable materials for forming the transparent conductive layer include tin dioxide doped with fluorine or antimony, indium-tin oxide (ITO), and the like. As the transparent substrate, soda glass, which is advantageous in terms of cost and strength, a glass substrate made of non-alkali glass which is not affected by alkali elution, or a transparent polymer film can be used. Examples of materials forming the transparent polymer film include triacetyl cellulose (TAC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), syndiotactic polystyrene (SPS), polyphenylene sulfide (PPS), polycarbonate (P
C), polyarylate (PAr), polysulfone (PS
F), polyester sulfone (PES), polyimide (P
I), polyether imide (PEI), cyclic polyolefin, brominated phenoxy resin and the like. In order to secure sufficient transparency, the coating amount of the conductive metal oxide is 0.01 to 10 per 1 m ² of glass or plastic substrate.
It is preferably 0 g.

It is preferable to use metal leads for the purpose of reducing the resistance of the conductive support. The metal lead is preferably made of a metal such as platinum, gold, nickel, titanium, aluminum, copper or silver. A metal lead is deposited on the transparent substrate by vapor deposition, sputtering, etc., and conductive tin oxide, IT
It is preferable to provide a transparent conductive layer such as an O film. The decrease in the amount of incident light due to the installation of the metal leads is preferably within 10%, more preferably 1 to 5%.

(B) Photosensitive layer In the photosensitive layer, the semiconductor fine particles act as a photoconductor and absorb light to separate charges to generate electrons and holes. In the dye-sensitized semiconductor fine particles, light absorption and generation of electrons and holes thereby occur mainly in the dye, and the semiconductor fine particles play a role of receiving and transmitting the electrons or holes. The semiconductor used in the present invention is preferably an n-type semiconductor in which a conductor electron serves as a carrier under photoexcitation and gives an anode current.

(1) Semiconductor The semiconductor used in the present invention includes a single semiconductor (silicon, germanium, etc.), a III-V group compound semiconductor, a metal chalcogenide (oxide, sulfide, selenide, composite thereof, etc.), A compound having a perovskite structure (strontium titanate, calcium titanate, sodium titanate, barium titanate, potassium niobate, etc.) may be used.

Examples of preferred metal chalcogenides are titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium or tantalum oxides, cadmium, zinc, lead, Examples thereof include sulfides of silver, antimony or bismuth, selenides of cadmium or lead, tellurides of cadmium and the like. Examples of other compound semiconductors include phosphides such as zinc, gallium, indium and cadmium, gallium-arsenic or copper-
Examples thereof include indium selenide and copper-indium sulfide. Furthermore, M _x O _y S _z and M _1x M _2y O _z (M, M ₁ and M ₂
Each represents a metal element, and x, y, and z are the number of combinations in which the valence is neutral).

The semiconductor used in the present invention is preferably Si,
TiO ₂ , SnO ₂ , Fe ₂ O ₃ , WO ₃ , ZnO, Nb ₂ O ₅ , CdS, ZnS, Pb
S, Bi ₂ S ₃ , CdSe, CdTe, SrTiO ₃ , GaP, InP, GaAs, CuIn
S ₂ or CuInSe ₂ , more preferably TiO ₂ , ZnO, Sn
O ₂ , Fe ₂ O ₃ , WO ₃ , Nb ₂ O ₅ , CdS, PbS, CdSe, SrTiO ₃ , In
P, GaAs, CuInS ₂ or CuInSe ₂ , particularly preferably Ti
O ₂ or Nb ₂ O ₅ , most preferably TiO ₂ . TiO ₂
Preferably TiO ₂ containing anatase 70% among, particularly preferably TiO ₂ 100% anatase. It is also effective to dope a metal for the purpose of increasing electron conductivity in these semiconductors. The metal to be doped is preferably a divalent or trivalent metal. It is also effective to dope the semiconductor with a monovalent metal for the purpose of preventing a reverse current from flowing from the semiconductor to the charge transport layer.

The semiconductor used in the present invention may be a single crystal or a polycrystal, but a polycrystal is preferable from the viewpoints of manufacturing cost, securing of raw materials, energy payback time, and the like, and a porous film made of fine semiconductor particles is particularly preferable. In addition, a part of the amorphous portion may be included.

The particle size of the semiconductor fine particles is generally on the order of nm to μm, but the average particle size of the primary particles obtained from the diameter when converting the projected area into a circle is preferably 5 to 200 nm,
More preferably, it is 8 to 100 nm. The average particle size of the semiconductor fine particles (secondary particles) in the dispersion is preferably 0.01-
It is 30 μm. Two or more kinds of semiconductor fine particles having different particle size distributions may be mixed and used, and in this case, the average particle size of the small particles is preferably 25 nm or less, more preferably
It is 10 nm or less. For the purpose of scattering incident light and improving the light capture rate, it is also preferable to mix semiconductor particles having a large particle size, for example, about 100 to 300 nm.

Two or more kinds of semiconductor fine particles of different kinds may be mixed and used. When two or more kinds of semiconductor fine particles are mixed and used, one of them is preferably TiO ₂ , ZnO, Nb ₂ O ₅ or SrTiO ₃ . The other is preferably SnO ₂ , Fe ₂ O ₃ or WO ₃ . Further preferred combinations include combinations of ZnO and SnO ₂ , ZnO and WO ₃ , ZnO and SnO ₂ and WO _{3, and the} like. When two or more kinds of semiconductor fine particles are mixed and used, each particle size may be different. In particular, a combination of TiO ₂ , ZnO, Nb ₂ O ₅ or SrTiO ₃ having a large particle size and a small SnO ₂ , Fe ₂ O ₃ or WO ₃ is preferable. Preferably, particles having a large particle size are 100 nm or more and particles having a small particle size are 15 nm or less.

As a method for producing semiconductor fine particles, Sakubana's “Sol-Gel Method Science” Agne Jofusha (1998), Technical Information Institute “Sol-Gel Method Thin Film Coating Technology” (1995 ), Etc., and Tadao Sugimoto, "Synthesis and Size Morphology Control of Monodisperse Particles by New Synthesis Gel-Sol Method," Materia, Vol. 35, No. 9, 1012-1018.
The gel-sol method described in page (1996) and the like is preferable. Also
A method developed by Degussa to produce an oxide by high-temperature hydrolysis of a chloride in an oxyhydrogen salt can also be preferably used.

When the semiconductor fine particles are titanium oxide, the sol-gel method, gel-sol method, and high-temperature hydrolysis method in chloride oxyhydrogen salt are all preferable. Applied Technology "Gihodo Publishing (1997)
It is also possible to use the sulfuric acid method or the chlorine method described in 1. Furthermore, as a sol-gel method, Barbe et al.
American Ceramic Society, Volume 80, Volume 12
No., pages 3157-3171 (1997), and Burnside
Rano Chemistry of Materials, Volume 10, 9
No. 2419 to 2425 is also preferable.

(2) Semiconductor fine particle layer When the semiconductor fine particle layer is formed on the conductive support, other than the method of coating the conductive support with a dispersion or colloidal solution containing semiconductor fine particles, the above-mentioned method is used. It is also possible to use a sol-gel method or the like. Considering the mass production of photoelectric conversion devices, the physical properties of dispersion liquids or colloidal solutions containing semiconductor particles, the flexibility of the conductive support, and the like, it is relatively desirable to use a wet film forming method. As a wet film forming method, a coating method, a printing method, an electrolytic deposition method and an electrodeposition method are typical.
In addition, a method of oxidizing a metal, a method of depositing a metal solution in a liquid phase by ligand exchange or the like (LPD method), a method of depositing by a sputtering method, a CVD method, or a metal that thermally decomposes on a heated substrate The SPD method of spraying an oxide precursor to form a metal oxide can also be used.

As a method for preparing a dispersion of semiconductor fine particles, in addition to the sol-gel method described above, a method of mashing with a mortar,
Examples thereof include a method of pulverizing and dispersing with a mill, a method of precipitating as fine particles in a solvent in synthesizing a semiconductor and using the particles as they are.

The dispersion medium used in the dispersion liquid of semiconductor fine particles is
Water or various organic solvents (methanol, ethanol, isopropyl alcohol, citronellol, terpineol,
Dichloromethane, acetone, acetonitrile, ethyl acetate, etc.). At the time of dispersion, a polymer such as polyethylene glycol, hydroxyethyl cellulose or carboxymethyl cellulose, a surfactant, an acid or a chelating agent may be used as a dispersion aid, if necessary.
By changing the molecular weight of polyethylene glycol, the viscosity of the dispersion liquid can be adjusted, and the semiconductor fine particle layer that is difficult to peel off can be formed, and the porosity of the semiconductor fine particle layer can be controlled. Therefore, it is preferable to add polyethylene glycol. .

Examples of preferred coating methods include a roller method and a dip method as an application system, an air knife method and a blade method as a metering system, and JP-B-58-4589 as a method in which the application and the metering can be performed in the same part. Wire bar method disclosed in No.
The slide hopper method, the extrusion method, the curtain method and the like described in U.S. Pat. Nos. 2,681,294, 2,761,419 and 2,761,791 can be mentioned. A spin method or a spray method is also preferable as a general-purpose machine. As a wet printing method, intaglio, a rubber plate, screen printing, etc. are preferable, including the three major printing methods of letterpress, offset and gravure. The film forming method may be selected from these depending on the liquid viscosity and the wet thickness.

The semiconductor fine particle layer is not limited to a single layer, and a dispersion of semiconductor fine particles having different particle diameters may be applied in multiple layers, or a layer containing different types of semiconductor fine particles (or different binders, additives, etc.) may be formed in multiple layers. It can also be applied. The multi-layer coating is effective even when the film thickness is insufficient by one-time coating.

In general, as the thickness of the semiconductor fine particle layer (same as the thickness of the photosensitive layer) increases, the amount of supported dye per unit projected area increases, so that the light capture rate increases, but the diffusion distance of generated electrons increases. Therefore, the loss due to charge recombination becomes large. Therefore, the preferable thickness of the semiconductor fine particle layer is 0.1 to 1
It is 00 μm. When using the photoelectric conversion element of the present invention in a photovoltaic cell, the thickness of the semiconductor fine particle layer is preferably 1 to 30 μm,
More preferably, it is 2 to 25 μm. The coating amount of the semiconductor fine particles per 1 m ^{2 of the} conductive support is preferably 0.5 to 100.
g, more preferably 3 to 50 g.

After the semiconductor fine particles are coated on the conductive support, the semiconductor fine particles are brought into electronic contact with each other and the coating strength and the adhesion to the conductive support are improved.
It is preferable to perform heat treatment. The heating temperature in the heat treatment is preferably 40 to 700 ° C, more preferably 100 to 60.
It is 0 ° C. The heating time is about 10 minutes to 10 hours.
When a substrate having a low melting point or softening point such as a polymer film is used, high temperature treatment is not preferable because it causes deterioration of the substrate. In terms of cost, the temperature is as low as possible (eg 50
It is preferable to perform the heat treatment at a temperature of up to 350 ° C. 5n lower temperature
It becomes possible by heat treatment in the presence of small semiconductor fine particles of m or less, mineral acid, or metal oxide precursor, and also by irradiation with ultraviolet rays, infrared rays, microwaves, etc., or by applying an electric field or ultrasonic waves. it can. At the same time, in addition to the above irradiation and application, heating, decompression, oxygen plasma treatment, pure water cleaning, solvent cleaning, in order to remove unnecessary organic substances, etc.
It is preferable to use gas cleaning or the like in combination as appropriate.

The semiconductor fine particle layer preferably has a large surface area so that many dyes can be adsorbed. The surface area of the semiconductor fine particle layer coated on the conductive support is preferably 10 times or more, and more preferably 100 times or more of the projected area. This upper limit is not particularly limited, but is usually about 1000 times.

(3) Dye The sensitizing dye used in the photosensitive layer is not particularly limited as long as it has absorption characteristics in the visible region and near infrared region and can sensitize a semiconductor, but metal complex dyes, methine dyes, Porphyrin type dyes and phthalocyanine type dyes can be preferably used, and among them, metal complex dyes are particularly preferable. In addition, in order to widen the wavelength range of photoelectric conversion as much as possible and increase the conversion efficiency,
Two or more kinds of dyes can be used in combination. in this case,
It is possible to select the dyes to be used together and the ratio thereof so as to match the wavelength range and intensity distribution of the desired light source.

The dye preferably has an appropriate interlocking group capable of adsorbing to the surface of the semiconductor fine particles. Examples of preferred linking groups include -COOH
Group, -OH group, -SO ₃ H group, acidic group such as -P (O) (OH) ₂ group and -OP (O) (OH) ₂ group, oxime, dioxime, hydroxyquinoline, salicylate and α -A chelating group having π conductivity such as ketoenolate may be used. Of these, a —COOH group, a —P (O) (OH) ₂ group and a —OP (O) (OH) ₂ group are particularly preferred. These bonding 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 contains an acidic group as in the case of forming a squarylium ring or a croconium ring, this portion may be used as a binding group. The preferred sensitizing dyes used in the photosensitive layer will be specifically described below.

(A) Metal Complex Dyes Among the metal complex dyes, metal phthalocyanine dyes, metal porphyrin dyes and ruthenium complex dyes are preferable, and ruthenium complex dyes are particularly preferable. Examples of ruthenium complex dyes include U.S. Pat.Nos. 4,927,721, 4,884,537 and 50.
No. 84365, No. 5350644, No. 5463057, No. 5525440, JP-A-7-249790, Tokuyohei 10-504512, WO98 / 50393,
Examples thereof include those described in JP-A-2000-26487.

The ruthenium complex dye used in the present invention is preferably represented by the following general formula (II): (A ₁ ) _p Ru (Ba) (Bb) (Bc) ... (II). In the general formula (II), A ₁ represents a mono- or bidentate ligand, preferably Cl, SCN, H ₂ O, Br,
It is a ligand selected from the group consisting of I, CN, NCO, SeCN, β-diketone derivatives, oxalic acid derivatives and dithiocarbamic acid derivatives. p is an integer of 0 to 3. Ba, Bb and Bc each independently represent an organic ligand represented by any of the following formulas B-1 to B-10.

[0063]

[Chemical 3]

In formulas B-1 to B-10, each R ₁ represents a hydrogen atom or a substituent, and examples of the substituent include a halogen atom,
A substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, the aforementioned acidic group and Examples include chelating groups. Here, the alkyl part of the alkyl group and aralkyl group may be linear or branched, and the aryl part of the aryl group and aralkyl group may be monocyclic or polycyclic (fused ring, ring assembly). )
May be Ba, Bb and Bc may be the same or different. The ruthenium complex dye represented by the general formula (II) may contain only one or two of Ba, Bb and Bc.

Specific examples of the metal complex dye that can be preferably used in the present invention are shown below, but the present invention is not limited thereto.

[0066]

[Chemical 4]

[0067]

[Chemical 5]

(B) Methine Dyes Preferred methine dyes that can be used in the present invention are polymethine dyes such as cyanine dyes, merocyanine dyes and squarylium dyes. Examples of polymethine dyes include those disclosed in
11-35836, 11-67285, 11-86916, 11-97725
No. 11, No. 11-158395, No. 11-163378, No. 11-214730,
Examples thereof include dyes described in JP-A Nos. 11-214731, 11-238905, JP-A 2000-26487, European Patents 892411, 911841 and 991092. Specific examples of preferable methine dyes are shown below.

[0069]

[Chemical 6]

[0070]

[Chemical 7]

(4) Adsorption of Dye on Semiconductor Fine Particles When adsorbing a dye on semiconductor fine particles, a method of immersing a conductive support having a well-dried semiconductor fine particle layer in a solution of the dye, or a solution of the dye Can be applied to the semiconductor fine particle layer. In the case of the former method, a dipping method, a dipping method, a roller method, an air knife method or the like can be used. When the dipping method is used, the dye may be adsorbed at room temperature or may be heated under reflux as described in JP-A-7-249790. In the case of the latter method, a wire bar method, a slide hopper method, an extrusion method, a curtain method, a spin method, a spray method or the like can be used. Alternatively, a dye may be applied in an image form by an inkjet method or the like, and the image itself may be used as a photoelectric conversion element.

The solvent used for the dye solution (adsorption liquid) is preferably alcohols (methanol, ethanol, t-butanol, benzyl alcohol, etc.), nitriles (acetonitrile, propionitrile, 3-methoxypropionitrile, etc.). , Nitromethane, halogenated hydrocarbons (dichloromethane, dichloroethane, chloroform, chlorobenzene, etc.), ethers (diethyl ether, tetrahydrofuran, etc.), dimethyl sulfoxide, amides (N,
N-dimethylformamide, N, N-dimethylacetamide, etc.), N-methylpyrrolidone, 1,3-dimethylimidazolidinone, 3-methyloxazolidinone, esters (ethyl acetate, butyl acetate, etc.), carbonates ( Diethyl carbonate, ethylene carbonate, propylene carbonate, etc.), ketones (acetone, 2-butanone, cyclohexanone, etc.), hydrocarbons (hexane, petroleum ether, benzene, toluene, etc.) or mixed solvents thereof.

The unadsorbed dye is preferably removed immediately by washing after the adsorption step. The washing is preferably carried out in a wet washing tank using an organic solvent such as acetonitrile or an alcohol solvent.

The amount of the dye adsorbed is preferably 0.01 to 100 mmol per unit area (1 m ² ) of the semiconductor fine particle layer.
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. With such an amount of dye adsorbed, the sensitizing effect of the semiconductor fine particles can be sufficiently obtained. If the amount of dye adsorbed is too small, the sensitizing effect will be insufficient, and if the amount of dye adsorbed is too large, the dye not attached to the semiconductor will float and the sensitizing effect will decrease. In order to increase the adsorption amount of the dye, it is preferable to heat-treat the semiconductor fine particles before the adsorption. In order to prevent water from adsorbing to the surface of the semiconductor fine particles, it is preferable to quickly adsorb the dye at a temperature of the semiconductor fine particle layer of 60 to 150 ° C. without returning to room temperature after the heat treatment.

(5) Additives to Dye Adsorbing Liquid A colorless compound is added to the dye adsorbing liquid for the purpose of reducing the interaction such as aggregation between dyes or increasing the amount of adsorbed dye. It may be co-adsorbed on the microparticles. Examples of such additives include steroid compounds having a carboxyl group (chenodeoxycholic acid, etc.), sulfonic acid compounds (and sulfonates), ureido compounds having at least one ureido group, alkali metal salts, alkaline earth metal salts, etc. Can be preferably used. These may be used alone or in combination.

Particularly preferable additives for the purpose of reducing the aggregation of the dye include steroid compounds having a carboxyl group having a surface-active property (chenodeoxycholic acid etc.) and the following sulfonates.

[Chemical 8]

Specific examples of preferable ureido compounds are shown below. The amount of the ureido compound added is preferably 0.1 to 1000 times mol, more preferably 1 to 500 times mol, and particularly preferably 10 to 100 times mol, relative to the dye.

[Chemical 9]

Among the alkali metal salts and alkaline earth metal salts, alkali metal salts are preferable, and lithium salts are particularly preferable. The anion species forming these salts are not particularly limited, and include halogens (fluorine, chlorine, bromine, iodine, etc.),
Carboxylic acid, sulfonic acid, phosphonic acid, sulfonamide, sulfonylimide (bistrifluoromethanesulfonimide, bispentafluoroethanesulfonimide, etc.), sulfonylmethide, sulfuric acid, thiocyanic acid, cyanic acid, perchloric acid, tetrafluoroboric acid , Hexafluorophosphoric acid and the like. Among them, iodine, bistrifluoromethanesulfonimide, thiocyanic acid, tetrafluoroboric acid or a salt of hexafluorophosphoric acid is preferable, iodine, a salt of bistrifluoromethanesulfonimide or tetrafluoroboric acid is more preferable, and an iodine salt is particularly preferable. . The amount of the alkali metal salt or alkaline earth metal salt added is preferably 0.1 to 1000 times mol, more preferably 1 to 500 times mol, and particularly preferably 10 to 100 times mol, of the dye.

(C) Charge Transport Layer The charge transport layer contains a charge transport material having a function of supplementing electrons to the oxidized form of the dye. The charge transport material used in the present invention is (i) a charge transport material involving ions,
(ii) It may be a charge-transporting material that involves carrier movement in a solid. (i) Examples of the charge transport material involving ions include a molten salt electrolyte composition containing a redox counter ion, a solution in which redox pair ions are dissolved (electrolyte), and a redox pair solution in a polymer matrix. Examples thereof include a so-called gel electrolyte composition impregnated in a gel, a solid electrolyte composition, and the like. (Ii) Examples of the charge transport material involved in carrier transfer in a solid include an electron transport material and a hole transport material. Can be mentioned. A plurality of these charge transport materials may be used in combination. In the present invention, it is preferable to use a molten salt electrolyte composition or an electrolytic solution for the charge transport layer.

(1) Molten Salt Electrolyte Composition From the viewpoint of achieving both photoelectric conversion efficiency and durability, it is preferable to use a molten salt electrolyte as the charge transport material. The molten salt electrolyte is a liquid at room temperature or an electrolyte having a low melting point, examples of which are WO95 / 18456 and JP-A-8-2595.
43, Electrochemistry, Vol. 65, No. 11, page 923 (1997) and the like, and pyridinium salts, imidazolium salts, triazolium salts and the like. The melting point of the molten salt is preferably 100 ° C. or lower, and particularly preferably liquid at around room temperature.

The molten salt used in the present invention has the following general formula (Y-
It is preferably represented by any of a), (Yb) and (Yc).

[0082]

[Chemical 10]

In formula (Ya), Q _y1 represents an atomic group forming a 5- or 6-membered aromatic cation with a nitrogen atom. Q
_y1 is preferably composed of an atom selected from the group consisting of carbon atom, hydrogen atom, nitrogen atom, oxygen atom and sulfur atom. The 5-membered ring formed by Q _y1 is an oxazole ring, a thiazole ring, an imidazole ring, a pyrazole ring, an isoxazole ring, a thiadiazole ring, an oxadiazole ring,
It is preferably a triazole ring, an indole ring or a pyrrole ring, more preferably an oxazole ring, a thiazole ring or an imidazole ring, particularly preferably an oxazole ring or an imidazole ring. The 6-membered ring formed by Q _y1 is a pyridine ring, a pyrimidine ring, a pyridazine ring,
A pyrazine ring or a triazine ring is preferable, and a pyridine ring is particularly preferable.

In the general formula (Yb), A _y1 represents a nitrogen atom or a phosphorus atom.

In the general formulas (Ya), (Yb) and (Yc), R _{y1 to} R _y
y11 is independently a substituted or unsubstituted alkyl group (preferably having 1 to 24 carbon atoms, may be linear or branched, or may be cyclic, for example, a methyl group , Ethyl group, propyl group, isopropyl group, pentyl group, hexyl group, octyl group, 2-ethylhexyl group,
t-octyl group, decyl group, dodecyl group, tetradecyl group, 2-hexyldecyl group, octadecyl group, cyclohexyl group, cyclopentyl group, etc., or a substituted or unsubstituted alkenyl group (preferably having 2 to 24 carbon atoms) ,
It may be linear or branched and represents, for example, a vinyl group or an allyl group. R _{y1 to} R _y11 each independently represent, more preferably, an alkyl group having 2 to 18 carbon atoms or an alkenyl group having 2 to 18 carbon atoms, and particularly preferably an alkyl group having 2 to 6 carbon atoms.

Two or more of R _{y2 to} R _{y5 in} the general formula (Yb) may be bonded to each other to form a non-aromatic ring containing A _y1, and R _y6 to the general formula (Yc) to Two or more of R _y11 may be linked to each other to form a ring.

The above Q _y1 and R _{y1 to} R _y11 may have a substituent. Preferred examples of this substituent include a halogen atom (F, Cl, Br, I, etc.), a cyano group, an alkoxy group (methoxy group, ethoxy group, methoxyethoxy group, methoxyethoxyethoxy group, etc.), aryloxy group (phenoxy group, etc.). Etc.), alkylthio group (methylthio group, ethylthio group, etc.), alkoxycarbonyl group (ethoxycarbonyl group, etc.), carbonic acid ester group (ethoxycarbonyloxy group, etc.), acyl group (acetyl group, propionyl group, benzoyl group, etc.), sulfonyl Group (methanesulfonyl group, benzenesulfonyl group, etc.), acyloxy group (acetoxy group, benzoyloxy group, etc.), sulfonyloxy group (methanesulfonyloxy group, toluenesulfonyloxy group, etc.), phosphonyl group (diethylphosphonyl group, etc.), Amido group (acetylamino group, benzoyl group Amino group, etc.), carbamoyl group (N, N-dimethylcarbamoyl group, etc.), alkyl group (methyl group, ethyl group, propyl group, isopropyl group, cyclopropyl group, butyl group, 2-carboxyethyl group, benzyl group, etc.) , Aryl groups (phenyl group, toluyl group, etc.), heterocyclic groups (pyridyl group, imidazolyl group,
Furanyl group etc.), alkenyl group (vinyl group, 1-propenyl group etc.), silyl group, silyloxy group and the like.

The molten salt represented by any of the general formulas (Ya), (Yb) and (Yc) may form a multimer via Q _y1 and any of R _{y 1 to} R _y11. .

In the general formulas (Ya), (Yb) and (Yc), X ⁻ represents an anion. Preferred examples of X ⁻ are halide ions (I ⁻ , Cl ⁻ , Br ^−, etc.), SCN ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ ,
_{(CF 3 SO 2) 2 N} -, (CF 3 CF 2 SO 2) 2 N -, CH 3 SO 3 -, CF 3 SO 3 -, CF 3
COO ⁻ , Ph ₄ B ⁻ , (CF ₃ SO ₂ ) ₃ C ^{− and the} like. X ^- is I ^-, SC
More preferably, it is N ⁻ , CF ₃ SO ₃ ⁻ , CF ₃ COO ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ or BF ₄ ⁻ .

Specific examples of the molten salt preferably used in the present invention are shown below, but the present invention is not limited thereto.

[0091]

[Chemical 11]

[0092]

[Chemical 12]

[0093]

[Chemical 13]

[0094]

[Chemical 14]

[0095]

[Chemical 15]

[0096]

[Chemical 16]

The molten salt may be used alone or in combination of two or more kinds. In addition, other iodine salts such as LiI and LiB
Alkali metal salts such as F ₄ , CF ₃ COOLi, CF ₃ COONa, LiSCN and NaSCN can also be used together. The amount of the alkali metal salt added is preferably 0.02 to 2% by mass, more preferably 0.1 to 1% by mass, based on the entire composition.

The molten salt electrolyte is preferably in a molten state at room temperature, and it is preferable not to use a solvent in the composition containing the molten salt electrolyte. The solvent described below may be added, but the content of the molten salt is preferably 50% by mass or more, and particularly preferably 90% by mass or more, based on the entire composition.
Further, it is preferable that 50 mass% or more of the salt contained in the composition is an iodine salt. The molten salt electrolyte composition may be gelled and used as described below.

Iodine is preferably added to the molten salt electrolyte composition, and in this case, the content of iodine is preferably 0.1 to 20% by mass, and 0.5 to 5% by mass based on the whole composition.
More preferably, it is mass%.

(2) Electrolyte Solution The electrolyte solution is preferably composed of an electrolyte, a solvent and additives. Examples of the electrolyte used in the electrolytic solution, I ₂ and iodide (metal iodide such as LiI, NaI, KI, CsI, CaI ₂ ,
Tetraalkylammonium iodide, pyridinium iodide, quaternary ammonium compounds such as imidazolium iodide, etc.) combination, Br ₂ and bromide (metal bromide such as LiBr, NaBr, KBr, CsBr, CaBr ₂ , tetraalkylammonium) Bromide, quaternary ammonium compound such as pyridinium bromide, bromine salt, etc.), metal complex such as ferrocyanate-ferricyanate or ferrocene-ferricinium ion, sodium polysulfide, sulfur compound such as alkylthiol-alkyldisulfide , Viologen dyes, hydroquinone-quinone, and the like. Among them, an electrolyte in which I ₂ and LiI or a quaternary ammonium compound iodine salt such as pyridinium iodide or imidazolium iodide is combined is preferable.
The electrolytes may be mixed and used.

The electrolyte concentration in the electrolytic solution is preferably 0.1 to 1
It is 0M, and more preferably 0.2 to 4M. When iodine is added to the electrolytic solution, the preferable addition concentration of iodine is 0.01 to 0.5M.

The solvent used for the electrolytic solution is a compound which can exhibit excellent ionic conductivity by having low viscosity and improving ion mobility, or by having high dielectric constant and improving effective carrier concentration. desirable. Examples of such solvents 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. , Chain ethers such as polyethylene glycol dialkyl ether, 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, polypropylene glycol Lumpur, polyhydric alcohols such as glycerin, acetonitrile, glutarodinitrile, methoxy acetonitrile, propionitrile, nitrile compounds such as benzonitrile, dimethyl sulfoxide, aprotic polar substances such as sulfolane, water and the like. These solvents may be mixed and used.

Also, J. Am. Ceram. Soc., 80 (12) 3157.
-3171 (1997), tert-butylpyridine, and basic compounds such as 2-picoline and 2,6-lutidine are preferably added to the above-described molten salt electrolyte composition or electrolytic solution. The basic compound to be added is preferably non-volatile. Further, a basic compound having a charge (pyridine derivative, imidazole derivative, etc.) can be preferably used, and a pyridine compound having a negative charge can be particularly preferably used. The preferable concentration range when the basic compound is added to the electrolytic solution is 0.05 to 2M. When added to the molten salt electrolyte composition, the mass ratio of the basic compound to the entire composition is preferably 0.1 to 40 mass%, more preferably 1 to 2
It is 0% by mass.

(3) Gel Electrolyte Composition In the present invention, the above-mentioned molten salt electrolyte composition or electrolytic solution is prepared by a method such as polymer addition, oil gelling agent addition, polymerization containing polyfunctional monomers, and polymer crosslinking reaction. It can also be used by gelling (solidifying). If gelation occurs due to addition of polymer, use “Polymer Electrolyte Revi
The compounds described in ews-1 and 2 "(JR MacCallum and CAVincent co-edited, ELSEVIER APPLIED SCIENCE) can be used, but polyacrylonitrile and polyvinylidene fluoride are particularly preferably used. Gelation by addition of oil gelling agent In case of making it, Industrial Science Magazine (J. Chem. Soc. Japan, Ind. Chem. Sec.), 46, 779
(1943), J. Am. Chem. Soc., 111, 5542 (1989), J. Ch.
em. Soc., Chem. Commun., 1993, 390, Angew. Chem. I
nt. Ed. Engl., 35, 1949 (1996), Chem. Lett., 1996,
885, and J. Chem. Soc., Chem. Commun., 1997, 545
Although the compounds described in 1) can be used, it is preferable to use the compounds having an amide structure. An example of gelling an electrolytic solution is described in JP-A No. 11-185863, and an example of gelling a molten salt electrolyte is also described in JP-A No. 2000-58140, and these are also applicable to the present invention.

When the polymer is gelated by a crosslinking reaction, it is desirable to use a polymer having a crosslinkable reactive group and a crosslinking agent together. In this case, the preferred crosslinkable reactive group is an amino group, a nitrogen-containing heterocycle (pyridine ring, imidazole ring, thiazole ring, oxazole ring, triazole ring, morpholine ring, piperidine ring, piperazine ring, etc.) The agent is a bifunctional or higher functional reagent capable of undergoing an electrophilic reaction with respect to a nitrogen atom (halogenated alkyls, halogenated aralkyls, sulfonic acid esters, acid anhydrides, acid chlorides, isocyanate compounds, α, β-unsaturated compounds). Saturated sulfonyl compounds, α, β-unsaturated carbonyl compounds, α, β-unsaturated nitrile compounds, etc.). The cross-linking techniques described in JP-A Nos. 2000-17076 and 2000-86724 can also be applied.

(4) Hole Transport Material In the present invention, an organic solid hole transport material, an inorganic solid hole transport material, or a combination of both materials is used in place of the ion conductive electrolyte such as molten salt. be able to.

(A) Organic Hole Transport Material Examples of organic hole transport materials that can be preferably used in the present invention include J. Hagen, et al., Synthetic Metal, 89,
215-220 (1997), Nature, Vol.395, 8 Oct., p583-585
(1998), WO97 / 10617, JP-A-59-194393, JP-A-5-234.
681, U.S. Pat.No. 4,923,774, JP-A-4-308688, U.S. Pat.No. 4,764,625, JP-A-3-269084, and JP-A-4-129271.
No. 4, No. 4-175395, No. 4-264189, No. 4-290851, No. 4-
364153, 5-25473, 5-239455, 5-320634
No. 6, No. 6-1972, No. 7-138562, No. 7-252474, No. 11-1
Aromatic amines described in JP-A-11-149821
No. 11-148067, No. 11-176489, etc., and the like. Also, Adv. Mater.,
9, No.7, p557 (1997), Angew. Chem. Int. Ed. Engl.,
34, No.3, p303-307 (1995), JACS, Vol.120, No.4, p6
64-672 (1998), etc., oligothiophene compounds, K.
Murakoshi, et al., Chem. Lett. P471 (1997), the polypyrrole, “Handbook of Organic Conductive Mol.
ecules and Polymers, Vol. 1,2,3,4 ”(NALWA, WILE
Y publication), polyacetylene and its derivatives, poly
Conductive polymers such as (p-phenylene) and its derivatives, poly (p-phenylene vinylene) and its derivatives, polythienylene vinylene and its derivatives, polythiophene and its derivatives, polyaniline and its derivatives, polytoluidine and its derivatives, etc. It can be preferably used.

Nature, Vol.395, 8 Oct., p583-585 (199
As described in 8), a compound containing a cation radical such as tris (4-bromophenyl) aminium hexachloroantimonate may be added to the hole transport material to control the dopant level. Further, a salt such as Li [(CF ₃ SO ₂ ) ₂ N] may be added in order to control the potential of the oxide semiconductor surface (compensation of the space charge layer).

(B) Inorganic hole transport material A p-type inorganic compound semiconductor is used as the inorganic hole transport material.
And its bandgap is preferably 2 eV or more.
The upper limit is more preferably 2.5 eV or higher. Also, p-type mineralization
The ionization potential of the compound semiconductor returns the holes of the dye
To do this, the ionization potential of the dye adsorption electrode
Needs to be smaller. P-type depending on the dye used
Preferred range of ionization potential for inorganic compound semiconductors
Different enclosures, but generally 4.5-5.5 eV, more preferred
It is 4.7 to 5.3 eV. Preferred p-type inorganic compound semiconductor
The body is a compound semiconductor containing monovalent copper.
Is CuI, CuSCN, CuInSe₂, Cu (In, Ga) Se₂, CuGaSe₂, Cu
₂O, CuS, CuGaS₂, CuInS₂, CuAlSe₂Etc. During ~
However, CuI and CuSCN are preferable, and CuI is most preferable.
Examples of other p-type inorganic compound semiconductors include GaP, NiO, and Co.
O, FeO, Bi₂O₃, MoO₂, Cr ₂O₃Etc.

(5) Formation of Charge Transport Layer The charge transport layer can be formed by either of two methods. One is to attach the counter electrode on the photosensitive layer first,
In this method, a liquid charge transport layer is sandwiched in the gap. The other is a method of directly providing a charge transport layer on the photosensitive layer.
The opposite pole will be added later.

In the case of the former method, when the charge transport layer is sandwiched, a normal pressure process utilizing a capillary phenomenon due to dipping or the like or a vacuum process of replacing the gas phase in the gap with a liquid phase by making the pressure lower than the normal pressure is carried out. Available.

In the latter method, when a wet charge transport layer is used, a counter electrode is usually applied while still undried to prevent liquid leakage at the edge portion. When the gel electrolyte composition is used, it may be solidified by a method such as polymerization after being applied by a wet method. The solidification may be performed before or after applying the counter electrode. When forming a charge transport layer composed of an electrolytic solution, a wet organic hole transport material, a gel electrolyte composition, etc., the same method as the method for forming the semiconductor fine particle layer described above can be used.

When the solid electrolyte composition or the solid hole transport material is used, the charge transport layer may be formed by a dry film forming process such as a vacuum deposition method or a CVD method, and then the counter electrode may be provided. The organic hole transport material can be introduced into the electrode by a vacuum deposition method, a casting method, a coating method, a spin coating method, a dipping method, an electrolytic polymerization method, a photoelectrolytic polymerization method or the like. The inorganic solid compound can be introduced into the electrode by a casting method, a coating method, a spin coating method, a dipping method, an electrolytic deposition method, an electroless plating method or the like.

(D) Counter Electrode The counter electrode may have a single-layer structure of a counter electrode conductive layer made of a conductive material, or may be composed of a counter electrode conductive layer and a supporting substrate, like the above-mentioned conductive support. Examples of the conductive agent used for the counter conductive layer include metals (platinum, gold, silver, copper, aluminum, magnesium, indium, etc.), carbon, conductive metal oxides (indium-tin composite oxide, fluorine-doped tin oxide, etc.). ) And the like. Among these, platinum, gold,
Silver, copper, aluminum and magnesium are preferred. The substrate used for the counter electrode is preferably a glass substrate or a plastic substrate, and the above conductive agent can be applied or vapor-deposited on the substrate. The thickness of the counter electrode conductive layer is not particularly limited, but is preferably 3 nm to 10 μm. The surface resistance of the counter conductive layer is preferably as low as possible, preferably 50 Ω / □ or less, and more preferably 20 Ω / □ or less.

Since light may be irradiated from either or both of the conductive support and the counter electrode, in order for the light to reach the photosensitive layer, at least one of the conductive support and the counter electrode is substantially transparent. I wish I had it. From the viewpoint of improving power generation efficiency, it is preferable to make the conductive support transparent and allow light to enter from the side of the conductive support. In this case, the counter electrode preferably has a property of reflecting light. To obtain this property,
As a counter electrode, glass or plastic having a metal or conductive oxide deposited thereon, or a metal thin film may be used.

For the counter electrode, a conductive agent is applied directly on the charge transport layer,
It may be plated or vapor-deposited (PVD, CVD), or may be placed by attaching the conductive layer side of a substrate having a conductive layer. As in the case of the conductive support, it is preferable to use a metal lead for the purpose of reducing the resistance of the counter electrode, especially when the counter electrode is transparent.
The preferred embodiment of the metal lead is the same as that of the conductive support.

(E) Other layers In order to prevent a short circuit between the counter electrode and the conductive support, a dense semiconductor thin film layer should be previously coated as an undercoat layer between the conductive support and the photosensitive layer. Is preferred. The method of preventing a short circuit by this undercoat layer is particularly effective when an electron transport material or a hole transport material is used for the charge transport layer. The subbing layer is preferably TiO ₂ , SnO ₂ , Fe ₂ O ₃ , WO ₃ , ZnO or Nb ₂ O ₅
And more preferably TiO ₂ . The undercoat layer can be applied by, for example, a spray pyrolysis method described in Electrochim. Acta, 40, 643-652 (1995), a sputtering method, or the like. The thickness of the undercoat layer is preferably 5
~ 1000 nm, more preferably 10-500 nm.

A functional layer such as a protective layer or an antireflection layer may be provided on the outer surface of one or both of the conductive support and the counter electrode, or between the conductive layer and the substrate or between the substrates. The method of forming these functional layers can be appropriately selected from a coating method, a vapor deposition method, a sticking method and the like depending on the material.

(F) Specific Example of Internal Structure of Photoelectric Conversion Element As described above, the internal structure of the photoelectric conversion element can have various forms according to the purpose. If roughly divided into two, it is possible to have a structure in which light can enter from both sides and a structure in which light can enter from only one side. Examples of preferable internal structures of the photoelectric conversion element of the present invention are shown in FIGS.

In the structure shown in FIG. 2, the photosensitive layer 20 and the charge transport layer 30 are interposed between the transparent conductive layer 10a and the transparent counter electrode conductive layer 40a, and light is incident from both sides. Has become. In the structure shown in FIG. 3, the metal substrate 11 is partially provided on the transparent substrate 50a, the transparent conductive layer 10a is provided thereon, and the undercoat layer 60, the photosensitive layer 20, the charge transport layer 30, and the counter electrode conductive layer 40 are arranged in this order. And the support substrate 50 is further arranged,
The structure is such that light enters from the conductive layer side. The structure shown in FIG. 4 has a conductive layer 10 on a supporting substrate 50 and an undercoat layer 60.
The photosensitive layer 20 is provided via the above, the charge transport layer 30 and the transparent counter electrode conductive layer 40a are further provided, and the transparent substrate 50a partially provided with the metal lead 11 is arranged with the metal lead 11 side inside. The structure in which light is incident from the counter electrode side. In the structure shown in FIG. 5, a metal lead 11 is partially provided on a transparent substrate 50a, and a transparent conductive layer 10a (or 40a) is further provided between a set of an undercoat layer 60, a photosensitive layer 20, and a charge transport layer 30. Is a structure in which light is incident from both sides. The structure shown in FIG. 6 includes a transparent conductive layer 10a, an undercoat layer 60, and a transparent conductive layer 10a on a transparent substrate 50a.
The photosensitive layer 20, the charge transport layer 30, and the counter electrode conductive layer 40 are provided, and the support substrate 50 is disposed on the photosensitive layer 20, and the light is incident from the conductive layer side. The structure shown in FIG. 7 has a supporting substrate 50.
Having the conductive layer 10 on the top, the photosensitive layer 20 is provided via the undercoat layer 60, further the charge transport layer 30 and the transparent counter electrode conductive layer 40a are provided,
The transparent substrate 50a is arranged on this, and the structure is such that light enters from the counter electrode side. In the structure shown in FIG. 8, the transparent conductive layer 10a is provided on the transparent substrate 50a, the photosensitive layer 20 is provided via the undercoat layer 60, and the charge transport layer 30 and the transparent counter conductive layer 40 are further provided.
a is provided, and the transparent substrate 50a is arranged on this,
The structure is such that light enters from both sides. In the structure shown in FIG. 9, the conductive layer 10 is provided on the support substrate 50, the photosensitive layer 20 is provided via the undercoat layer 60, and the solid charge transport layer 30 is further provided.
A part of the counter electrode conductive layer 40 or the metal lead 11 is provided on this, and the structure is such that light enters from the counter electrode side.

[IV] Photocell The photocell of the present invention is one in which the photoelectric conversion element of the present invention is caused to work by an external load. Of the photovoltaic cells, the case where the charge transport material mainly consists of the ion transport material is called a photoelectrochemical cell, and the case where the main purpose is power generation by sunlight is called a solar cell.

The side surface of the photovoltaic cell is preferably sealed with a polymer, an adhesive or the like in order to prevent deterioration of the constituents and volatilization of the contents. The external circuit itself, which is connected to the conductive support and the counter electrode via the lead, may be a known one.

When the photoelectric conversion element of the present invention is applied to a solar cell, the internal structure of the cell is basically the same as that of the photoelectric conversion element described above. Further, the dye-sensitized solar cell using the photoelectric conversion element of the present invention can basically have the same module structure as the conventional solar cell module. In the solar cell module, cells are generally formed on a supporting substrate such as metal or ceramic, and the structure is covered with a filling resin or protective glass to take in light from the opposite side of the supporting substrate. It is also possible to use a transparent material such as tempered glass for the supporting substrate and construct a cell on the transparent material to take in light from the transparent supporting substrate side. Specifically, a module structure called super straight type, substrate type, potting type,
A substrate-integrated module structure used in an amorphous silicon solar cell or the like is known, and a dye-sensitized solar cell using the photoelectric conversion element of the present invention is also selected as appropriate depending on the purpose of use, place of use and environment. it can. Specifically, the structures and aspects described in Japanese Patent Application No. 11-8457 and Japanese Patent Application Laid-Open No. 2000-268892 are preferable.

[0124]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

Synthesis Example 1 Synthesis of Compound (2) In a toluene (120 ml) solution of tetraethoxy titanium (11.4 g) under a nitrogen atmosphere, β-cyclodextrin (11.3 g) was added.
g) was added and the mixture was heated under reflux for 2 hours. After lowering the temperature to 80 ° C., about 80 ml of toluene as a solvent was distilled off and cooled to room temperature.
The white residue thus deposited was filtered off and dried in vacuum at 50 ° C. to obtain 14.5 g of compound (2) as a white solid. When the composition ratio of the obtained compound (2) was confirmed by ¹ H-NMR, it was β-cyclodextrin: titanium element: ethoxy group = 1: 5: 5 (δ (2% D ₂ SO ₄ / D ₂ O): 4.85 (d), 3.72 (dd), 3.68 (b
s), 3.55-3.30 (m), 1.00 (t)).

Example 1 1. Preparation of Titanium Dioxide Particle Coating Liquid By the same method as that described in Barbe et al., Journal of American Ceramic Society, Volume 80, page 3157, except that the autoclave temperature was 230 ° C. 11% by mass titanium dioxide particle dispersion was obtained. The average size of the titanium dioxide particles in this dispersion was about 10 nm. 20 to titanium dioxide in this dispersion
Mass% polyethylene glycol (molecular weight 20000, Wako Pure Chemical Industries, Ltd.) was added and mixed to obtain a titanium dioxide particle coating solution.

2. Preparation of titanium dioxide electrode (1) Preparation of electrode for comparison Transparent conductive glass coated with fluorine-doped tin oxide (manufactured by Nippon Sheet Glass, surface resistance: about 10 Ω / cm ² )
120 μm of the above coating liquid on the conductive surface side of the
After being applied at a thickness of 30 ° C. and dried at 25 ° C. for 30 minutes, it was baked at 450 ° C. for 30 minutes using an electric furnace (Yamato Scientific muffle furnace FP-32 type). The amount of titanium dioxide applied was 18 g / m ² , and the thickness of the applied layer was 12 μm. After calcination, ruthenium complex dye cis- (dithiocyanate) -N, N'-bis (2,2'-bipyridyl-4,4'-dicarboxylic acid) ruthenium (II)
The complex (R-1) was immersed in the adsorbent for 16 hours. Adsorption temperature is 25
℃, the solvent of the adsorption liquid is ethanol and acetonitrile 1:
1 (volume ratio) mixture, and the concentration of the dye was 3 × 10 ⁻⁴ mol / liter. The titanium dioxide electrode with the adsorbed dye was washed sequentially with ethanol and acetonitrile, and then used as a comparison electrode.
T-1 was produced.

(2) Preparation of Pretreatment Electrode A transparent conductive glass was coated with a coating solution, dried and baked in the same manner as in the preparation method of the electrode T-1 described above, and then the compound (1) was added. Was immersed in a hydrochloric acid aqueous solution (treatment solution) for 3 hours at 25 ° C., washed with neutral water, and dried at 70 ° C. for 30 minutes. This was baked at 450 ° C. for 30 minutes using the above electric furnace and cooled. The coating amount after cooling increased by 0.1% to 12% of titanium dioxide, and there was no change in film thickness. Then, the ruthenium dye R-1 was adsorbed in the same manner as in the method for producing the electrode T-1 to produce a pretreatment electrode TB-1. The concentration of the compound (1) in the treatment liquid was 0.02 mol / liter, and the hydrogen chloride concentration was 0.4 mol / liter.

Pretreatment electrodes TB-2 to TB-13 were prepared in the same manner as in the preparation of pretreatment electrode TB-1, except that the compounds shown in Table 2 below were used in the treatment liquid instead of compound (1). It was made. Further, a comparative electrode TB-14 was produced in the same manner as the pretreatment electrode TB-1 except that a 0.1 mol / liter titanium tetrachloride aqueous solution was used as the treatment liquid.

[0130]

[Table 2]

(3) TiCl_FourFabrication of treatment electrodes Ruthenium dye after treatment with polysaccharide and baking
Before adsorbing R-1, 0.1 mol / liter titanium tetrachloride
Pretreatment except that it was re-treated with an aqueous solution of water and fired again.
Similar to the manufacturing method of electrodes TB-2 and TB-10 to TB-12, the following table
TiCl shown in 3 _FourPrepare the processing electrodes TC-1 to TC-4 respectively.
It was The treatment conditions with the titanium tetrachloride aqueous solution are 25 ° C,
It was 3 hours.

[0132]

[Table 3]

3. Preparation of photoelectric conversion element Dye-adsorbing titanium oxide electrode T-1 (2 cm x
2 cm) was overlaid with platinum vapor-deposited glass of the same size. Next, an electrolyte solution (1,3-dimethylimidazolium iodide (0.65mol /
l) and iodine (0.05 mol / l) in acetonitrile) were soaked and introduced into the electrode, and the photoelectric conversion element CS for comparison was used.
Got -1. As shown in FIG. 10, this photoelectric conversion element comprises a conductive glass 1 (glass 2 on which a conductive layer 3 is provided), a dye-adsorbed titanium dioxide layer 4, a charge transport layer 5, a platinum layer 6 and a glass. 7 has a structure in which layers are sequentially stacked. Further, the photoelectric conversion elements CS-15 and CS-16 for comparison, and the photoelectric conversion element of the present invention were prepared in the same manner as in the photoelectric conversion element CS-1 except that the electrodes were changed to those shown in Table 4 below. element
CS-2 to CS-14 and CS-17 to CS-20 were produced, respectively.

4. Measurement of photoelectric conversion efficiency Simulated sunlight was generated by passing light of a 500 W xenon lamp (manufactured by USHIO) through a spectral filter ("AM1.5" manufactured by Oriel). The intensity of this simulated sunlight is vertical
It was 100 mW / cm ² . Silver paste was applied to the end of the conductive glass of each photoelectric conversion element CS-1 to CS-20 to form a negative electrode, and this negative electrode and platinum vapor-deposited glass (positive electrode) were connected to a current-voltage measuring device (Keithley SMU238 type). . The photoelectric conversion efficiency was obtained by measuring the current-voltage characteristics while irradiating each photoelectric conversion element vertically with simulated sunlight. Table 4 below shows the conversion efficiency of each photoelectric conversion element.

[0135]

[Table 4]

From Table 4, as compared with the untreated photoelectric conversion element and the conventional photoelectric conversion element treated with titanium tetrachloride or alkoxytitanium, any of the photoelectric conversion elements of the present invention pretreated with the polysaccharide was converted. It can be seen that the efficiency is high. Further, it can be seen that the conversion efficiency is further improved by performing the titanium tetrachloride treatment after the treatment with the polysaccharide.

Example 2 The above comparative electrode T-1 was immersed in a treatment solution containing poly-β-cyclodextrin at 40 ° C. for 1.5 hours, washed with acetonitrile, and then dried in a dark place under a nitrogen stream. Processing electrode TA-1
Was produced. Further, the post-treatment electrodes TA-2 and TA-3 were produced in the same manner as the production of the electrode TA-1, except that the polysaccharide shown in Table 5 below was used for the post-treatment instead of poly-β-cyclodextrin. did. Further, in the same manner as in preparation of the electrode TA-1, except that the polysaccharide shown in Table 5 below was used for the post-treatment in place of the poly-β-cyclodextrin, and the additive shown in Table 5 below was added to the treatment liquid, Post-treatment electrodes TA-4 to TA-6 were produced. The concentration of the polysaccharide and the concentration of the additive in the treatment liquid were both 0.01 mol / liter, and the solvent used was a mixed solvent of acetonitrile / t-butanol (1/1).

Using the obtained post-treatment electrodes TA-1 to TA-6,
The photoelectric conversion elements CA-1 to CA of the present invention are manufactured by the same method as in Example 1.
-6 was produced. Table 5 shows the results of measuring the conversion efficiency of the photoelectric conversion elements CA-1 to CA-6 in the same manner as in Example 1.

[0139]

[Table 5]

From Table 5, it can be seen that the photoelectric conversion elements of the present invention post-treated with polysaccharides have higher conversion efficiency than the untreated photoelectric conversion elements. Further, it is understood that the conversion efficiency is further improved by adding a base, an ureido compound, polyethylene glycol or the like to the treatment liquid containing the polysaccharide.

Example 3 Long-wave ruthenium dye R in place of ruthenium complex dye R-1
-10, merocyanine dye M-3 or squarylium dye M-1
Photoelectric conversion elements CO-1 to CO-6 were respectively produced in the same manner as the above-mentioned photoelectric conversion element CS-1 or CS-3 except that was used. The concentration of the dye in the dye adsorbing liquid is 1 x
It was set to 10 ⁻⁴ mol / liter. Obtained photoelectric conversion element CO-1
As a result of measuring the conversion efficiencies of ~ CO-6 in the same manner as in Example 1, as shown in Table 6 below, the photoelectric conversion device of the present invention treated with the polysaccharide showed excellent conversion efficiency as in Example 1. It was

[0142]

[Table 6]

[0143]

As described in detail above, according to the production method of the present invention, a dye-sensitized photoelectric conversion element having excellent conversion efficiency can be obtained by treating semiconductor particles with a polysaccharide. In particular, when treated with a polysaccharide containing an element belonging to any of Groups 3 to 6 and Groups 12 to 15 of the periodic table, the conversion efficiency of the photoelectric conversion element can be further improved.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a structure of a preferable photoelectric conversion element of the present invention.

FIG. 2 is a partial cross-sectional view showing the structure of a preferable photoelectric conversion element of the present invention.

FIG. 3 is a partial cross-sectional view showing the structure of a preferable photoelectric conversion element of the present invention.

FIG. 4 is a partial cross-sectional view showing the structure of a preferable photoelectric conversion element of the present invention.

FIG. 5 is a partial cross-sectional view showing the structure of a preferable photoelectric conversion element of the present invention.

FIG. 6 is a partial cross-sectional view showing the structure of a preferable photoelectric conversion element of the present invention.

FIG. 7 is a partial cross-sectional view showing the structure of a preferable photoelectric conversion element of the present invention.

FIG. 8 is a partial cross-sectional view showing the structure of a preferable photoelectric conversion element of the present invention.

FIG. 9 is a partial cross-sectional view showing the structure of a preferable photoelectric conversion element of the present invention.

FIG. 10 is a partial cross-sectional view showing a structure of a photoelectric conversion element manufactured in an example.

[Explanation of symbols]

10 ... Conductive layer 10a ... Transparent conductive layer 11 ... Metal leads 20 ... Photosensitive layer 21 ... Semiconductor fine particles 22 ... Dye 23 ... Charge transport material 30 ... Charge transport layer 40 ... Counter electrode conductive layer 40a: Transparent counter electrode conductive layer 50 ... Substrate 50a ... Transparent substrate 60 ... Undercoat layer 1 ... Conductive glass 2 ... glass 3 ... Conductive layer 4 ... Dye adsorption titanium dioxide layer 5 ... Charge transport layer 6 ... Platinum layer 7 ... glass

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4C090 AA01 AA07 AA08 BA11 BB67                       BB84 BB92 BD32 CA36 CA46                       DA31                 5F051 AA14 BA13 DA20 FA02 GA02                       HA20                 5H032 AA06 AS06 AS16 BB07 EE16

Claims (4)

[Claims] 1. A method for producing a photoelectric conversion element having a photosensitive layer containing semiconductor fine particles having a dye adsorbed thereon and a conductive support, wherein the semiconductor fine particles are treated with a polysaccharide. Method for manufacturing conversion element. 2. A photoelectric conversion element manufactured by the method for manufacturing a photoelectric conversion element according to claim 1. 3. A photovoltaic cell using the photoelectric conversion element according to claim 2. 4. A compound obtained by mixing α, β or γ-cyclodextrin with a compound represented by the following general formula (I) in a molar ratio of 50: 1 to 1:50. MX _n (I) In the general formula (I), M represents an element belonging to any of Groups 3 to 6 and Groups 12 to 15 of the Periodic Table, X represents a halogen or an alkoxy group, n represents an integer of 2 to 6.