JP4169220B2 - Photoelectric conversion element - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a photoelectric conversion element, and more particularly to a photoelectric conversion element using semiconductor fine particles sensitized with a dye.
[0002]
[Prior art]
Photoelectric conversion elements are used in various optical sensors, copying machines, and photovoltaic power generation devices. Various systems such as those using metals, semiconductors, organic pigments and dyes, or combinations thereof have been put to practical use as photoelectric conversion elements.
U.S. Pat. Nos. 4,927,721, 4,684,537, 5,084,365, 5,350,644, 5,530,57, and 5,525,440, and Japanese Patent Application Laid-Open No. 7-249790 include a photoelectric conversion element using semiconductor fine particles sensitized with a dye (hereinafter referred to as a dye). (Abbreviated as a sensitized photoelectric conversion element), or materials and manufacturing techniques for producing the same. The first advantage of this method is that an inexpensive oxide semiconductor such as titanium dioxide can be used without being purified with high purity, and therefore a relatively inexpensive photoelectric conversion element can be provided. The second advantage is that the absorption of the dye used is broad, so that light in almost all wavelength regions of visible light can be converted into electricity. Since these characteristics are advantageous when applied to a photoelectric conversion element (so-called photochemical cell) for the purpose of converting solar energy into electricity, application in this direction is being actively studied.
[0003]
One of the points where improvement of the dye-sensitized photoelectric conversion element is required is to use an expensive ruthenium complex dye as the sensitizing dye, and the development of a photoelectric conversion element sensitized by an inexpensive organic dye is desired. It was. At this time, the problem is that the affinity between the organic dye and the oxide semiconductor is usually not so strong.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to provide a dye-sensitized photoelectric conversion element that is inexpensive and has high conversion efficiency by using an organic dye having high affinity with titanium dioxide.
[0005]
[Means for Solving the Problems]
As a result of research, it has been found that the photoelectric conversion elements shown below are suitable for the purpose of the present invention.
1. A photoelectric conversion element characterized by using fine particles of titanium oxide, zinc oxide, tin oxide, or tungsten oxide sensitized with a polymethine dye represented by the following general formula (I). Formula (I)
[0006]
[Formula 4]
[0007]
In the formula, X ₁ represents an atomic group necessary for completing a 5-membered or 6-membered heterocyclic ring which may be condensed, and X ₁ may further have a substituent. L ₁ , L ₂ , L ₃ and L ₄ each independently represents a methine group which may have a substituent. n ₁ represents 0 or 1, and R ₁ represents an aromatic group which may have a substituent or an aliphatic group which may have a substituent. n ₂ is an integer from 0 to 4, and X ₂ represents an atomic group necessary for completing a 5-membered or 6-membered nitrogen-containing heterocycle. L represents a linking group, Y represents an oxygen atom or NR ₂ , and R ₂ represents a hydrogen atom or an aromatic group which may have a substituent or an aliphatic group which may have a substituent. . n ₃ represents 0 or 1. W ₁ represents a counter ion when a counter ion is required to neutralize the charge. A is an oxygen atom, a sulfur atom, a selenium atom, or a substituent represented by general formula (II) or general formula (III).
Formula (II)
[0008]
[Chemical formula 5]
[0009]
In the formula, L ₅ , L ₆ , L ₇ , L ₈ and L ₉ are synonymous with L ₁ . n ₄ has the same meaning as n ₂ , and n ₅ has the same meaning as n ₁ . X ₃ has the same meaning as X ₁ , and R ₃ has the same meaning as R ₁ .
General formula (III)
[0010]
[Chemical 6]
[0011]
In the formula, L ₁₀ and L ₁₁ have the same meaning as L ₁ . n ₆ is synonymous with n ₂ . D ₁ and D ₁ ′ represent an atomic group necessary for forming an acidic nucleus.
2. The photoelectric conversion device according to (1) the general formula n ₃ in (I) is 0.
3. In the general formula (I), n ₃ is 0, and the sum of n ₁ and n ₂ is an integer of 2 or more and 5 or less, The photoelectric conversion element according to (1),
4). In the general formula (I), n ₃ is 0 and the sum of n ₁ and n ₂ is an integer of 2 or more and 5 or less, and the nitrogen-containing heterocycle formed by X ₂ is 3-alkyl rhodanine or A compound represented by formula (I), which is 2-thiobarbituric acid.
5. A photochemical battery using the photoelectric conversion element of the above 1, 2, 3 or 4.
The general formula (I) used in the present invention will be described in detail below.
[0012]
In the formula, X ₁ represents an atomic group necessary for completing a 5-membered or 6-membered heterocyclic ring which may be condensed, and X ₁ may further have a substituent.
Preferred examples of the heterocyclic ring completed with X ₁ include benzothiazole nucleus, benzoxazole nucleus, benzoselenazole nucleus, benzotelrazole nucleus, quinoline nucleus, benzimidazole nucleus, thiazoline nucleus, indolenine nucleus, oxadiazole nucleus. , Thiazole nucleus, imidazole nucleus, more preferably benzothiazole nucleus, benzoxazole nucleus, benzimidazole nucleus, benzoselenazole nucleus, quinoline nucleus, indolenine nucleus, particularly preferably benzothiazole nucleus, quinoline nucleus. is there. Examples of substituents on the ring include halogen (F, Cl, Br, I), cyano, alkoxy (methoxy, ethoxy, methoxyethoxy, etc.), aryloxy (phenoxy, etc.), alkyl (methyl, ethyl, cyclopropyl, cyclohexyl). , Trifluoromethyl, methoxyethyl, allyl, benzyl etc.), alkylthio (methylthio, ethylthio etc.), alkenyl (vinyl, 1-propenyl etc.), aryl (phenyl, thienyl, toluyl, chlorophenyl etc.) and the like.
[0013]
L ₁ , L ₂ , L ₃ and L ₄ each independently represents a methine group which may have a substituent. Examples of the substituent include a substituted or unsubstituted alkyl group (preferably having 1 to 12 carbon atoms, more preferably 1 to 7 carbon atoms such as methyl, ethyl, propyl, isopropyl, cyclopropyl, butyl, 2-carboxyl. Ethyl, benzyl, etc.), substituted or unsubstituted aryl groups (preferably having 6 to 10 carbon atoms, more preferably 6 to 8 carbon atoms such as phenyl, toluyl, chlorophenyl, o-carboxyphenyl), heterocyclic rings Groups (eg pyridyl, thienyl, furanyl, pyridyl, barbituric acid), halogen atoms (eg chlorine, bromine), alkoxy groups (eg methoxy, ethoxy), amino groups (preferably having 1 to 12 carbon atoms, Preferably 6 to 12, for example diphenyl Mino, methylphenylamino, 4-acetyl-piperazin-1-yl), etc. oxo group. These groups on the methine group may be linked to each other to form a ring such as a cyclopentene ring or a cyclohexene ring, or may form a ring with an auxiliary color group.
[0014]
R ₁ represents an aromatic group which may have a substituent or an aliphatic group which may have a substituent. The number of carbon atoms of the aromatic group is preferably 1 to 16, more preferably 5 to 6. The number of carbon atoms of the aliphatic group is preferably 1 to 10, more preferably 1 to 6. Examples of the unsubstituted aliphatic group and aromatic group include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, a phenyl group, and a naphthyl group.
[0015]
n ₁ is 0 or 1, n ₂ is an integer from 0 to 4, and preferably the sum of n ₁ and n ₂ is an integer from 2 to 5.
[0016]
X ₂ represents an atomic group necessary for completing a 5-membered or 6-membered nitrogen-containing heterocycle. Preferably the following nucleus is mentioned.
2-pyrazolin-5-one, pyrazolidine-3,5-dione, imidazolin-5-one, hydantoin, 2 or 4-thiohydantoin, 2-iminooxazolidine-4-one, 2-oxazolin-5-one, 2- Thiooxazolidine-2,4-dione, isoxazolin-5-one, 2-thiazoline-4-one, thiazolidine-4-one, thiazolidine-2,4-dione, rhodanine, thiazolidine-2,4-dithione, isorhodanine, Indan-1,3-dione, thiophen-3-one, thiophen-3-one-1,1-dioxide, indoline-2-one, indoline-3-one, indazolin-3-one, 2-oxoindazolinium 3-oxoindazolinium, 5,7-dioxo-6,7-dihydrothiazolo [3,2-a] Limidine, cyclohexane-1,3-dione, 3,4-dihydroisoquinolin-4-one, 1,3-dioxane-4,4-dione, barbituric acid, 2-thiobarbituric acid, chroman-2,4- Dione, indazolin-2-one, or pyrido [1,2-a] pyrimidine-1,3-dione, pyrazolo [1,5-b] quinazolone, pyrazolo [1,5-b] benzimidazole, 1,2, 3,4-tetrahydroquinoline-2,4-dione, 3-oxo-2,3-dihydrobenzo [d] thiophene-1,1-dioxide, 3-dicyanomethine-2,3-dihydrobenzo [d] thiophene-1 , 1-dioxide nucleus.
More preferably, 3-alkylrhodanine, 3-alkyl-2-thiooxazolidine-2,4-dione, 3-alkyl-2-thiohydantoin, 2-thiobarbituric acid, particularly preferably 3-alkylrhodanine, 2-thiobarbituric acid.
[0017]
L represents a linking group, preferably a divalent linking group having a length of 1 to 4 atoms, and may further have a substituent.
[0018]
Y is an oxygen atom or NR ₂ , and R ₂ is a hydrogen atom or an aromatic group which may have a substituent or an aliphatic group which may have a substituent.
[0019]
n ₃ represents 0 or 1. n ₃ is preferably 0.
[0020]
W ₁ represents a counter ion when a counter ion is required to neutralize the charge.
Whether a certain dye is a cation, an anion, or has a net ionic charge depends on its auxiliary color group and substituent. When the substituent has a dissociable group, it may be dissociated to have a negative charge, and in this case as well, the charge of the entire molecule is neutralized by W ₁ . Typical cations are inorganic or organic ammonium ions (eg, tetraalkylammonium ions, pyridinium ions) and alkali metal ions, while anions are specifically inorganic or organic anions. Well, for example, a halogen anion (eg, fluoride ion, chloride ion, bromide ion, iodide ion), substituted aryl sulfonate ion (eg, p-toluene sulfonate ion, p-chlorobenzene sulfonate ion), Aryl disulfonate ion (for example, 1,3-benzenedisulfonate ion, 1,5-naphthalenedisulfonate ion, 2,6-naphthalenedisulfonate ion), alkyl sulfate ion (for example, methyl sulfate ion), sulfate ion, thiocyanate Acid ion, perchlorine Ion, tetrafluoroborate ion, picrate ion, acetate ion and trifluoromethanesulfonate ion.
Further, an ionic polymer or another dye having a charge opposite to that of the dye may be used as the charge balance counter ion, or a metal complex ion (for example, bisbenzene-1,2-dithiolatonickel (III)) is also possible. is there.
[0021]
A is an oxygen atom, a sulfur atom, a selenium atom, or a substituent represented by general formula (II) or general formula (III). In the general formulas (II) and (III), L ₅ , L ₆ , L ₇ , L ₈ , L ₉ , L ₁₀ and L ₁₁ are synonymous with L ₁ . n ₄ and n ₆ are synonymous with n ₂ , and n ₅ is synonymous with n ₁ . X ₃ has the same meaning as X ₁ , and R ₃ has the same meaning as R ₁ .
[0022]
D ₁ and D ₁ ′ represent an atomic group necessary for forming an acidic nucleus. The acidic nucleus here is, for example, “The Theory of the Photographic Process” edited by James. (The Theory of the Photographic Process) 4th edition, defined by Macmillan Publisher, 1977, 198 pages. In a preferred form, the substituent involved in the resonance of D ₁ and D ₂ is, for example, a carbonyl group, a cyano group, a sulfonyl group, or a sulfenyl group. D ₁ ′ and D ₂ ′ represent the remaining atomic groups necessary for forming an acidic nucleus.
Specifically, US Pat. Nos. 3,567,719, 3,575,869, 3,804,634, 3,837,862, 4,002,480, 4,925,777, What is described in Kaihei 3-167546 etc. is mentioned. When D ₁ and D ₁ ′ and D ₂ and D ₂ ′ form an acyclic acidic nucleus, the end of the methine bond is malononitrile, alkanesulfonylacetonitrile, cyanomethylbenzofuranyl ketone, or cyanomethylphenyl ketone. Such a group.
When D ₁ and D ₁ 'form a cyclic acidic nucleus, form a 5- or 6-membered heterocycle consisting of carbon, nitrogen, and chalcogen (typically oxygen, sulfur, selenium, and tellurium) atoms To do.
[0023]
Specific examples of the compound represented by formula (I) of the present invention are shown below, but the present invention is not limited thereto.
[0024]
[Chemical 7]
[0025]
[Chemical 8]
[0026]
[Chemical 9]
[0027]
Embedded image
[0028]
Embedded image
[0029]
Synthesis of the compound represented by the general formula (I) used in the present invention is described in Dokl. Acad. Nauk SSSR, Vol. 177, p. 869 (1967), F.M. "Heterocyclic compounds-Cyanine dyes and related compounds-" by FM Harmer (John Wiley & Sons, New York (London, 1964), DM Starmer, "Heterocyclic Compounds-Special topics in heterocyclic chemistry", 482-515. (John Wiley & Sons, New York, London, 1977), JP 55-4501. No. 5 and European Patent Nos. 599,381A1, 599,382A1, 599,383A1, 599,384A1 and the references cited in these specifications can be referred to.
[0030]
The synthesis example of the compound used by this invention is shown.
Synthesis example 1
Synthesis of Exemplary Compound (S-1) Compound (S-1) can be synthesized according to the scheme shown below.
[0031]
Embedded image
[0032]
(A-1) 0.5 g and (B-1) 0.5 g are mixed in 10 ml of acetonitrile, 0.55 ml of triethylamine is added, and the mixture is stirred at room temperature for 3 hours. The obtained crystals were separated by suction filtration and recrystallized from a methanol-acetonitrile mixed solvent to obtain 0.10 g of (S-1).
(Λmax = 605nm (ε = 124000) (in methanol))
[0033]
Synthesis example 2
Synthesis of Exemplary Compound (S-13) Compound (S-13) can be synthesized according to the scheme shown below.
[0034]
Embedded image
[0035]
Mix 0.5 g of (A-2) and 1.0 g of (B-2) in 10 ml of acetonitrile, add 0.55 ml of triethylamine, and stir at room temperature for 4 hours. The obtained crystal was separated by suction filtration and recrystallized from a methanol-acetonitrile mixed solvent to obtain 0.30 g of (S-13).
(Λmax = 625nm (ε = 108000) (in methanol))
[0036]
Synthesis example 3
Synthesis of Exemplary Compound (S-21) Compound (S-21) can be synthesized according to the scheme shown below.
[0037]
Embedded image
[0038]
1.0 g of (A-3) and 1.7 g of (B-3) are mixed in 20 ml of acetonitrile, 2.0 ml of triethylamine is added, and the mixture is refluxed with heating for 10 minutes and further stirred at room temperature for 1 hour. The obtained crystal was separated by suction filtration and recrystallized from a methanol-acetonitrile mixed solvent to obtain 0.40 g of (S-21).
(Λmax = 615nm (ε = 46500) (in methanol))
[0039]
Next, a dye-sensitized photoelectric conversion element using a polymethine dye and a photochemical battery will be described in detail. The dye-sensitized photoelectric conversion element is an electrode comprising a conductive support and a layer (photosensitive layer) of semiconductor fine particles adsorbed with a polymethine dye coated on the conductive support. The photosensitive layer is designed according to the purpose and may have a single layer structure or a multilayer structure. The dyes in one photosensitive layer may be one kind or a mixture of various kinds. Light incident on the photosensitive layer excites the dye. The excitation dye has electrons with high energy, and these electrons are transferred from the dye to the conduction band of the semiconductor fine particles, and further reach the conductive support by diffusion. At this time, the dye molecules are in the form of oxidant, but the electrons on the electrodes return to the dye oxidant while working in the external circuit, and the dye-sensitized photoelectric conversion element functions as the negative electrode of this battery. .
[0040]
Hereinafter, the conductive support and the photosensitive layer will be described in detail.
The conductive support is a support made of glass or plastic having a conductive agent layer on the surface, such as a metal, which is conductive in itself. In the latter case, preferred conductive agents are metals (eg, platinum, gold, silver, copper, aluminum, rhodium, indium, etc.), carbon, or conductive metal oxides (indium-tin composite oxide, tin oxide doped with fluorine. Etc.).
The lower the surface resistance of the conductive support, the better. The range of the surface resistance is preferably 50 Ω / cm ² or less, more preferably 10 Ω / cm ² or less.
The conductive support is preferably substantially transparent. Substantially transparent means that the light transmittance is 10% or more, preferably 50% or more, particularly preferably 80% or more. As the transparent conductive support, a glass or plastic coated with a conductive metal oxide is preferable. When a transparent conductive support is used, light is preferably incident from the support side.
[0041]
The semiconductor fine particles are metal chalcogenides (eg, oxides, sulfides, selenides, etc.) or perovskite fine particles. Preferred examples of the metal chalcogenide include titanium, tin, zinc, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, tantalum oxide, cadmium sulfide, and cadmium selenide. Preferred perovskites include strontium titanate and calcium titanate. Of these, titanium oxide, zinc oxide, tin oxide, or tungsten oxide is used for the photoelectric conversion element of the present invention .
[0042]
As a method of coating the semiconductor fine particles on the conductive support, a method of coating a dispersion or colloidal solution of the semiconductor fine particles on the conductive support, a method of coating the precursor of the semiconductor fine particles on the conductive support, and air. Examples thereof include a method of obtaining a semiconductor fine particle film by hydrolysis with moisture therein. Examples of the method for preparing a dispersion of semiconductor fine particles include a method of pulverizing in a mortar, a method of dispersing while pulverizing using a mill, or a method of depositing fine particles in a solvent and using them as they are when a semiconductor is synthesized. . Examples of the dispersion medium include water or various organic solvents (for example, methanol, ethanol, dichloromethane, acetone, acetonitrile, ethyl acetate, etc.). During dispersion, a polymer, surfactant, acid, chelating agent, or the like may be used as a dispersion aid as necessary.
[0043]
The semiconductor fine particles preferably have a large surface area so that many dyes can be adsorbed. For example, in a state where semiconductor fine particles are coated on a support, the surface area is preferably 10 times or more, more preferably 100 times or more the projected area.
In general, as the thickness of the semiconductor fine particle layer increases, the amount of dye that can be carried per unit area increases, so that the light absorption efficiency increases. The preferred thickness of the semiconductor fine particle layer varies depending on the use of the device, but is typically 0.1 to 100 microns. When used as a photochemical battery, the thickness is preferably 1 to 50 microns, more preferably 3 to 30 microns. The semiconductor fine particles may be fired to adhere the particles to each other after being applied to the support.
[0044]
In order to adsorb the dye to the semiconductor fine particles, a method of immersing a well-dried semiconductor fine particle in a dye solution for a long time is general. The dye solution may be heated to 50 ° C. to 100 ° C. as necessary. The adsorption of the dye may be performed before or after application of the semiconductor fine particles. Further, the semiconductor fine particles and the pigment may be applied and adsorbed simultaneously. Unadsorbed dye is removed by washing. When baking a coating film, it is preferable to adsorb | suck a pigment | dye after baking. It is particularly preferable that the dye is quickly adsorbed after the baking and before water adsorbs on the surface of the coating film. One type of dye may be adsorbed or a mixture of several types may be used. In the case of mixing, the polymethine dyes of the present invention may be mixed together, as described in U.S. Pat. Nos. 4,927,721, 4,684,537, 5,084,365, 5,350,644, 5,630,57, 5,525,440, and JP-A-7-249790. The complex dye and the dye of the present invention may be mixed. When the application is a photochemical battery, a dye to be mixed is selected so as to make the wavelength range of photoelectric conversion as wide as possible.
Further, a colorless compound may be co-adsorbed for the purpose of reducing the interaction between dyes such as association. Examples of the hydrophobic compound to be co-adsorbed include steroid compounds having a carboxyl group (for example, cholic acid).
[0045]
The amount of the dye adsorbed to the semiconductor fine particle layer in the present invention is preferably 0.01 to 100 mmol per square meter of the coated film as the total amount of the dye, more preferably 0.1 to 50 mmol per square meter, and further preferably 0.5 to 20 mmol per square meter.
[0046]
After adsorbing the dye, the surface of the semiconductor fine particles may be treated with amines. Preferable amines include pyridine, 4-tert-butylpyridine, polyvinylpyridine and the like. These may be used as they are in the case of a liquid, or may be used by dissolving in an organic solvent.
[0047]
The dye-sensitized photoelectric conversion element thus prepared can be applied to various sensors and photochemical batteries. When applied to a photochemical battery, a charge transfer layer and a counter electrode are required. Hereinafter, the charge transfer layer and the counter electrode will be described in detail.
The charge transfer layer is a layer having a function of replenishing electrons to the oxidant of the dye. Typical examples include a liquid in which a redox couple is dissolved in an organic solvent, a so-called gel electrolyte in which a polymer matrix is impregnated with a liquid in which a redox pair is dissolved in an organic solvent, and a molten salt containing the redox couple.
Examples of the redox pair include a combination of iodine and iodide (eg, lithium iodide, tetrabutylammonium iodide, tetrapropylammonium iodide, etc.), alkyl viologen (eg, methyl viologen chloride, hexyl viologen bromide, benzyl viologen tetrafluoroborate). And its reduced form. A combination of polyhydroxybenzenes (eg, hydroquinone, naphthohydroquinone, etc.) and their oxidants. A combination of divalent and trivalent iron complexes (for example, red blood salt and yellow blood salt) can be used. Of these, a combination of iodine and iodide is preferred. As the organic solvent for dissolving them, an aprotic polar solvent (for example, acetonitrile, propylene carbonate, ethylene carbonate, dimethylformamide, dimethyl sulfoxide, sulfolane, 1,3-dimethylimidazolinone, 3-methyloxazolidinone, etc.) is preferable. Examples of the polymer used for the matrix of the gel electrolyte include polyacrylonitrile and polyvinylidene fluoride. Examples of the molten salt include those imparted with fluidity at room temperature by mixing polyethylene oxide with lithium iodide and at least one other lithium salt (eg, lithium acetate, lithium perchlorate, etc.). .
Since the redox couple becomes an electron carrier, a certain concentration is required. The preferred concentration is 0.01 mol / liter or more in total, more preferably 0.1 mol / liter, and particularly preferably 0.3 mol / liter or more.
[0048]
The counter electrode serves as the positive electrode of the photochemical battery. The counter electrode is usually synonymous with the conductive support described above, but the support is not necessarily required in a configuration in which the strength is sufficiently maintained. However, having a support is advantageous in terms of hermeticity.
In order for light to reach the photosensitive layer, at least one of the conductive support and the counter electrode described above must be substantially transparent. In the photochemical 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.
As the counter electrode of the photochemical battery, glass or plastic on which a metal or conductive oxide is vapor-deposited is preferable, and glass on which platinum is vapor-deposited is particularly preferable.
[0049]
In the photochemical battery, it is preferable to seal the side surface of the battery with a polymer, an adhesive or the like in order to prevent evaporation of components.
[0050]
【Example】
The method for producing the dye-sensitized photoelectric conversion element and the photochemical battery of the present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.
[0051]
Preparation of Titanium Dioxide Dispersion Teflon-coated inner 200ml stainless steel vessel with 15g titanium dioxide (Nippon Aerosil Degussa P-25), water 45g, dispersant (Aldrich Triton X-100) 1g, diameter 30 g of 0.5 mm zirconia beads (manufactured by Nikkato Co., Ltd.) was added and dispersed for 2 hours at 1500 rpm using a sand grinder mill (manufactured by Imex). The zirconia beads were filtered off from the dispersion.
[0052]
Preparation of photoelectric conversion element The above dispersion liquid was prepared using a glass rod on the conductive surface side of conductive glass coated with tin oxide doped with fluorine (TCO glass manufactured by Asahi Glass cut into a size of 20 mm x 20 mm). Applied. At this time, adhesive tape was applied to a part of the conductive surface side (3 mm from the end) to form a spacer, and glass was arranged so that the adhesive tape came to both ends, and 8 sheets were applied at a time. After application, the film was air-dried at room temperature for 1 day, and the adhesive tape was peeled off. (The part with the adhesive tape is used to make electrical contact with the measuring instrument during photoelectric conversion measurement.) Next, this glass is put into an electric furnace (Maffle furnace FP-32 manufactured by Yamato Scientific). Baked at 450 ° C. for 30 minutes. After the glass was taken out and cooled, it was immersed in an ethanol solution (3 × 10 ⁻⁴ mol / liter) of the dye of the present invention shown in Table 1 for 3 hours. The dyed glass was immersed in a 10% ethanol solution of 4-tert-butylpyridine for 30 minutes, then washed with ethanol and air dried.
[0053]
Preparation of Photochemical Battery The above photoelectric conversion element was overlapped with platinum vapor-deposited glass having the same size (the uncoated portion of the photoelectric conversion element was shifted so as not to contact the platinum vapor-deposited glass). Next, an electrolytic solution (0.05 mol / liter iodine using a mixture of acetonitrile and N-methyl-2-oxazolidinone in a volume ratio of 90 to 10) as a solvent is utilized in the gap between the two glasses using a capillary phenomenon. .5 mol / liter solution).
[0054]
Measurement of photoelectric conversion efficiency Simulated sunlight that does not contain ultraviolet rays was generated by passing light from a 500 W xenon lamp (made by Ushio) through an AM1.5G filter (made by Oriel) and a sharp cut filter (Kenko L-42). . The intensity of this light was 50 mW / cm ² .
The photoelectric conversion element of the present invention was irradiated with this light, and the generated electricity was measured with a current-voltage measuring device (Keutley 238 type). Table 1 summarizes the open circuit voltage, short circuit current, form factor, and conversion efficiency of the photochemical battery thus determined.
[0055]
[Table 1]
[0056]
Although any of the dyes of the present invention is an organic dye, high photoelectric conversion characteristics are recognized.
[0057]
【The invention's effect】
According to the present invention, a dye-sensitized photoelectric conversion element having high photoelectric conversion characteristics using an organic dye is provided.

Claims (5)

A photoelectric conversion element characterized by using fine particles of titanium oxide, zinc oxide, tin oxide, or tungsten oxide sensitized with a polymethine dye represented by the following general formula (I). Formula (I)
In the formula, X ₁ represents an atomic group necessary for completing a 5-membered or 6-membered heterocyclic ring which may be condensed, and X ₁ may further have a substituent. L ₁ , L ₂ , L ₃ and L ₄ each independently represents a methine group which may have a substituent. n1 represents 0 or 1, R ₁ represents an aliphatic group which may have an optionally substituted aromatic group or a substituent. n2 is an integer from 0 to 4, X ₂ represents an atomic group necessary to complete a nitrogen-containing heterocyclic ring of 5 or 6 membered. L represents a linking group, Y represents an oxygen atom or NR ₂ , and R ₂ represents a hydrogen atom or an aromatic group which may have a substituent or an aliphatic group which may have a substituent. . n3 represents 0 or 1. W ₁ represents a counter ion when a counter ion is required to neutralize the charge. A is an oxygen atom, a sulfur atom, a selenium atom, or a substituent represented by general formula (II) or general formula (III). Formula (II)
In the formula, L ₅ , L ₆ , L ₇ , L ₈ and L ₉ are synonymous with L ₁ . n4 is synonymous with n2, and n5 is synonymous with n1. X ₃ has the same meaning as X ₁ , and R ₃ has the same meaning as R ₁ . General formula (III)
In the formula, L ₁₀ and L ₁₁ have the same meaning as L ₁ . n6 is synonymous with n2. D ₁ and D ₁ ′ represent an atomic group necessary for forming an acidic nucleus. 2. The photoelectric conversion element according to claim 1, wherein n3 is 0 in the general formula (I). 2. The photoelectric conversion element according to claim 1, wherein in general formula (I), n3 is 0 and the sum of n1 and n2 is an integer of 2 or more and 5 or less. In the general formula (I), n3 is 0, the sum of n1 and n2 is an integer of 2 or more and 5 or less, and the nitrogen-containing heterocycle formed by X ₂ is 3-alkylrhodanine or 2-thio It is a barbituric acid, The photoelectric conversion element of Claim 1 characterized by the above-mentioned . A photochemical cell using the photoelectric conversion element according to claim 1, 2, 3 or 4.