JP5130775B2 - Photoelectrochemical cell - Google Patents

Description

  The present invention relates to a photoelectrochemical cell such as a solar cell.

In recent years, in order to prevent global warming, reduction of CO ₂ released into the atmosphere has been demanded. As an effective means for reducing CO ₂ , for example, promotion of utilization of a solar system using a photoelectrochemical cell such as a pn junction type silicon solar cell that can be installed on a roof of a house has been proposed. However, the single crystal, polycrystal and amorphous silicon used in the silicon photoelectrochemical cell have a problem of high cost because high temperature and high vacuum conditions are required in the production process.
On the other hand, Non-Patent Document 1 proposes a photoelectrochemical cell including a photoelectric conversion element in which a thin film of titanium oxide having a photosensitizing dye adsorbed on its surface is laminated on a conductive substrate, a charge transfer layer, and a counter electrode. Yes. Compared to conventional silicon-based solar cells, the photoelectrochemical cell is expected to be cheaper because many of the materials used are inexpensive and high-temperature high-vacuum conditions are not required in the manufacturing process. .
By the way, the charge transfer layer proposed in Non-Patent Document 1 uses iodine / iodide or the like as an electrolyte, and uses a volatile solvent such as acetonitrile as a solvent. A sealing method is required so that the charge transfer layer does not volatilize.
For example, Patent Document 1 proposes a photoelectrochemical cell that is sealed using a glass frit.

Nature (pages 737-740, 353, 1991) JP 2000-348783

By the way, in photoelectrochemical cells using glass frit, the problem is that after introducing the electrolytic solution from the hole previously opened in the cell, the hole is hermetically sealed so that the electrolytic solution does not evaporate. is there. As a method for sealing the hole, it is usually sealed with an adhesive or the like that hardens at room temperature so that the electrolyte does not evaporate when the hole is sealed. However, with such a sealing method, since the airtightness is poor, high durability cannot be expected.
It is also known to melt the glass tube installed in the cell with a gas burner and seal it, but there is also the possibility of igniting flammable vapor due to the presence of flammable electrolyte filled in the cell. It is not necessarily a safe sealing method.

Therefore, the present inventors examined a method for producing a photoelectrochemical cell in which the charge transfer layer such as an electrolyte or a solvent contained in the charge transfer layer is not lost even when stored at a high temperature, and was excellent in durability. A photoelectrochemical cell was found.
That is, the present invention relates to a photoelectrochemical cell in which a laminate including a conductive substrate, semiconductor fine particles adsorbed with a photosensitizing dye, a charge transfer layer, and a counter electrode is sealed with a sealant. The present invention provides a photoelectrochemical battery characterized in that a tube is mounted in a hole formed in the battery, and the tip and / or the inside of the tube is sealed with a glass frit.

  In the photoelectrochemical cell of the present invention, a tube is mounted in a hole formed in the photoelectrochemical cell, and the tip and / or the inside of the tube is sealed with a glass frit, and volatile such as acetonitrile. Excellent durability due to prevention of volatilization of electrolytes such as solvents and iodine.

Hereinafter, the present invention will be described in detail.
The photoelectrochemical cell of the present invention is a photoelectrochemical cell formed by sealing a laminate including a conductive substrate, semiconductor fine particles adsorbed with a photosensitizing dye, a charge transfer layer and a counter electrode with a sealant. The photoelectrochemical cell is characterized in that a tube is mounted in a hole formed in the photoelectrochemical cell, and the tip and / or the inside of the tube is sealed with a glass frit.
In a wet photoelectrochemical cell, an electrolytic solution is filled between a conductive substrate and a counter electrode that are in contact with a layer of semiconductor fine particles to which a photosensitizing dye is adsorbed (hereinafter sometimes referred to as a dye-adsorbing semiconductor particle layer). .
In the dry photoelectrochemical cell, the conductive substrate and the counter electrode are stacked via a solid hole transport material, and the semiconductor fine particles adsorbing the photosensitizing dye are contained in the solid hole transport material. Contained.
The photoelectrochemical cell of the present invention is effective for both wet and dry processes, but it is more effective especially in the case of a wet photoelectrochemical cell.

The wet photoelectrochemical cell of the present invention will be described below as an example. A specific example is shown in FIG. A conductive substrate (8), a counter electrode (9) facing the conductive substrate (8), and a semiconductor fine particle layer (3) on which the photosensitizing dye (4) is adsorbed exist between these. In the case of a wet photoelectrochemical cell, the semiconductor particle layer (3) (with the dye adsorbed) is sealed with a sealing material (10) in a state filled with the electrolytic solution (5).
The conductive substrate (8) is composed of a substrate (1) and a conductive layer (2) in order from the top. The counter electrode (9) is composed of a substrate (7) and a conductive layer (6) in order from the bottom.
A tube (11) for introducing an electrolytic solution is mounted in a hole opened in the photoelectrochemical cell.

The lower the electrical resistance of the conductive layer (the conductive substrate (2) and the counter electrode (6)) in the conductive substrate (8) and the counter electrode (9) used in the photoelectrochemical cell of the present invention is preferred. In addition, the conductive layer (2) of the conductive substrate preferably has a high transmittance in a high wavelength region, specifically a region longer than 350 nm, specifically a transmittance of 80% or more. .
Examples of the conductive substance used for the conductive layer include metals such as iron, nickel, chromium, titanium, aluminum, platinum, gold, silver, cobalt, palladium, copper, tantalum, ruthenium, tungsten, zinc, and tin; Indium-tin composite oxide (ITO), conductive metal oxides such as tin oxide doped with fluorine; carbon and the like. The conductive layer may be a laminate of two or more of these conductive materials.
Specific examples of the conductive layer include a conductive substance itself or a nonconductive substrate surface formed by vapor deposition, sputtering, adhesion, or the like on a nonconductive substrate surface.
The conductive substrate (8) preferably has a texture structure on the surface of the conductive material in order to confine incident light and effectively use it.
In the counter electrode (9), the sheet or foil made of the conductive material may simultaneously serve as the substrate of (7).

  Examples of the non-conductive substrate ((1) as the conductive substrate and (7) as the counter electrode) in the conductive substrate (8) and the counter electrode (9) include glass.

  As an electroconductive board | substrate (8) and a counter electrode (9), what apply | coated electroconductive metal oxide to glass etc. is preferable. Among these, conductive glass in which a conductive layer made of tin dioxide doped with fluorine is laminated is particularly preferable because it has low electrical resistance, excellent light transmittance, and is easily available.

  The semiconductor fine particles used in the present invention are fine particles having a semiconductor characteristic with a primary particle size of about 1 to 5000 nm, preferably about 5 to 500 nm. For the purpose of improving photoelectric conversion efficiency by reflection, semiconductor fine particles having different primary particle diameters may be mixed. Tubes and hollow fine particles may be used.

Examples of the material of the semiconductor fine particles include titanium oxide, tin oxide, zinc oxide, iron oxide, tungsten oxide, zirconium oxide, hafnium oxide, strontium oxide, indium oxide, cerium oxide, yttrium oxide, lanthanum oxide, vanadium oxide, niobium oxide. , Metal oxides such as tantalum oxide, gallium oxide, nickel oxide, strontium titanate, barium titanate, potassium niobate, sodium tantalate; metal halides such as silver iodide, silver bromide, copper iodide, copper bromide Zinc sulfide, titanium sulfide, indium sulfide, bismuth sulfide, cadmium sulfide, zirconium sulfide, tantalum sulfide, molybdenum sulfide, silver sulfide, copper sulfide, tin sulfide, tungsten sulfide, antimony sulfide, and other metal sulfides; cadmium selenide, Zirconium selenide, ce Metal selenides such as zinc selenide, titanium selenide, indium selenide, tungsten selenide, molybdenum selenide, bismuth selenide, lead selenide; cadmium telluride, tungsten telluride, molybdenum telluride, zinc telluride, tellurium Metal tellurides such as bismuth iodide; metal phosphides such as zinc phosphide, gallium phosphide, indium phosphide, cadmium phosphide; gallium arsenide, copper-indium-selenide, copper-indium-sulfide, silicon, germanium, etc. Is mentioned. Further, it may be a mixture of two or more of zinc oxide / tin oxide and tin oxide / titanium oxide.
Among them, titanium oxide, tin oxide, zinc oxide, iron oxide, tungsten oxide, zirconium oxide, hafnium oxide, strontium oxide, indium oxide, cerium oxide, yttrium oxide, lanthanum oxide, vanadium oxide, niobium oxide, tantalum oxide, gallium oxide, Metal oxides such as nickel oxide, strontium titanate, barium titanate, potassium niobate, sodium tantalate, zinc oxide / tin oxide, tin oxide / titanium oxide are relatively inexpensive and readily available, and photosensitizing dyes Titanium oxide is particularly preferable because it is easily adsorbed.

The surface of the semiconductor fine particles may be subjected to chemical plating using a titanium tetrachloride aqueous solution or electrochemical plating using a titanium trichloride aqueous solution. This increases the surface area of the semiconductor fine particles, increases the purity in the vicinity of the semiconductor fine particles, masks impurities such as iron existing on the surface of the semiconductor fine particles, or increases the connectivity and bonding properties of the semiconductor fine particles. can do.
The semiconductor fine particles preferably have a large surface area so that many photosensitizing dyes can be adsorbed. For this reason, the surface area of the semiconductor fine particle layer coated on the substrate is preferably 10 times or more, more preferably 100 times or more the projected area. This upper limit is usually about 1000 times.
The layer of semiconductor fine particles may be a single layer of semiconductor fine particles, but is usually a layer composed of a plurality of semiconductor fine particles and a plurality of semiconductor fine particles having different particle diameters.

In the case of a wet photoelectrochemical cell, a semiconductor fine particle layer is usually formed on a conductive substrate, and then a photosensitizing dye is adsorbed on the fine particles of the layer.
As a method for forming a semiconductor fine particle layer on a conductive substrate, a method in which semiconductor fine particles are directly formed as a thin film on a conductive substrate by spraying or the like; a semiconductor fine particle thin film is electrically deposited using a conductive substrate as an electrode Method: A method in which a slurry of semiconductor fine particles is applied on a conductive substrate and then dried, cured, or baked is exemplified.

The method for applying the semiconductor fine particle slurry onto the conductive substrate will be described in more detail. Examples thereof include a doctor blade, squeegee, spin coating, dip coating, and screen printing. In these methods, the average particle size in the dispersed state of the semiconductor fine particles in the slurry is preferably 0.01 nm to 100 μm.
The dispersion medium for dispersing the slurry is not particularly limited as long as it can disperse the semiconductor fine particles. Water or an alcohol solvent such as ethanol, isopropanol, t-butanol or terpineol; an organic solvent such as a ketone solvent such as acetone. Is used. These water and organic solvent may be a mixture. The dispersion may contain a polymer such as polyethylene glycol; a surfactant such as Triton-X; an organic acid or inorganic acid such as acetic acid, formic acid, nitric acid or hydrochloric acid; and a chelating agent such as acetylacetone.
It is preferable to form the semiconductor fine particle layer by firing the conductive substrate coated with the semiconductor fine particle slurry. The firing temperature is usually lower than the melting point of the conductive layer or substrate, and the upper limit of the firing temperature is 1200 ° C., preferably 600 ° C. or less. The firing time is usually within 10 hours. The thickness of the semiconductor fine particle layer on the conductive substrate is usually from 0.1 to 200 μm, preferably from 1 to 50 μm.

  Another method for forming a layer of semiconductor fine particles on a conductive substrate at a relatively low temperature is a hydrothermal method in which a layer of porous semiconductor fine particles is formed by hydrothermal treatment (a dye-sensitized photoelectrochemical cell for practical use). 2nd lecture (Hideki Kajiura) 63-65, published by NTS (2003)), electrophoretic electrodeposition method (T. Miyasaka et al., Chem.) Of electrodepositing a dispersion of dispersed semiconductor particles on a substrate. Lett., 1250 (2002)), a method of applying a semiconductor paste to a substrate, pressing after drying (a dye-sensitized photoelectrochemical cell for practical use, 12th lecture (Takehiko Tsuji), pages 312 to 313, NTS Issue (2003)).

  The photosensitizing dye used in the present invention has absorption in the visible light region and / or the infrared light region, and one or more of various metal complexes and organic dyes can be used. A photosensitizing dye having a functional group such as a carboxyl group, a hydroxyalkyl group, a hydroxyl group, a sulfone group, or a carboxyalkyl group in the molecule of the photosensitizing dye is preferred because it tends to be adsorbed to a semiconductor quickly. Moreover, since it is excellent in photoelectric conversion efficiency and durability, a metal complex is preferable. As the metal complex, metal phthalocyanines such as copper phthalocyanine and titanyl phthalocyanine, chlorophyll, hemin, and ruthenium, osmium, iron, and zinc complexes described in JP-A-1-220380 and JP-A-5-504023 are used. Can do.

  More detailed examples of ruthenium complexes include cis-bis (isothiocyanate) bis (2,2'-bipyridyl-4,4'-dicarboxylate) -ruthenium (II) bis-tetrabutylammonium, cis-bis (iso Thiocyanate) bis (2,2'-bipyridyl-4,4'-dicarboxylate) -ruthenium (II), tris (isothiocyanate) -ruthenium (II) -2,2 ': 6', 2 "-thepyridine- Tris-tetrabutylammonium 4,4 ', 4 "-tricarboxylate, cis-bis (isothiocyanate) (2,2'-bipyridyl-4,4'-dicarboxylate) (2,2'-bipyridyl-4, 4'-dinonyl) ruthenium (II) and the like.

Examples of the organic dye include metal-free phthalocyanine, cyanine dye, merocyanine dye, xanthene dye, triphenylmethane dye, squarylium dye, and the like. Specific examples of cyanine dyes include NK1194 and NK3422 (both manufactured by Nippon Photosensitive Dye Research Laboratories). Specific examples of merocyanine dyes include NK2426 and NK2501 (both manufactured by Nippon Photosensitivity Laboratories). Examples of xanthene dyes include uranin, eosin, rose bengal, rhodamine B, dibromofluorescein and the like. Examples of the triphenylmethane dye include malachite green and crystal violet.
Examples of the coumarin dye include NKX-2777 (manufactured by Hayashibara Biochemical Laboratories) (see the following structural formula).
Examples of organic dyes such as indoline include D149 (manufactured by Mitsubishi Paper Industries) (see the following structural formula).

As a method for adsorbing a photosensitizing dye to semiconductor fine particles laminated on a conductive substrate, for example, a laminate comprising a well-dried semiconductor fine particle layer and a conductive substrate in a solution containing a photosensitizing dye for several hours. The method of immersing is mentioned. Adsorption of the photosensitizing dye may be performed at room temperature (25 ° C.), may be performed under heating, or may be performed while refluxing a solution containing the photosensitizing dye.
The photosensitizing dye can be adsorbed before the semiconductor fine particle layer is formed on the conductive substrate, or the semiconductor fine particles and the photosensitizing dye may be applied to the conductive substrate at the same time. A method of adsorbing the photosensitizing dye to the formed semiconductor fine particle layer is more preferable. When the semiconductor fine particle layer is heat-treated, the photosensitizing dye adsorption is preferably performed after the heat treatment, and a method of adsorbing the photosensitizing dye after the heat treatment and before water is adsorbed on the surface of the semiconductor fine particle layer is particularly preferable. preferable.

In order to suppress the reduction of the sensitizing effect due to floating of the photosensitizing dye not attached to the semiconductor fine particles, it is desirable to remove the unadsorbed photosensitizing dye by washing.
The photosensitizing dye to be adsorbed may be one kind or a mixture of several kinds. When the application is a photoelectrochemical cell, it is preferable to select a photosensitizing dye to be mixed so that the wavelength range of photoelectric conversion of irradiation light such as sunlight is as wide as possible. Further, the adsorption amount of the photosensitizing dye to the semiconductor fine particles is preferably 0.01 to 1 mmol per 1 g of the semiconductor fine particles. Such a dye amount is preferable because the sensitizing effect in the semiconductor fine particles can be sufficiently obtained and the reduction of the sensitizing effect due to floating of the dye not attached to the semiconductor fine particles tends to be suppressed.
The photosensitizing dyes adsorbed on the semiconductor fine particles may be the same or different. For example, a 300-500 nm photosensitizing dye is adsorbed on the first layer, a 500-700 nm photosensitizing dye is adsorbed on the second layer, and a 700-900 nm photosensitizing dye is adsorbed on the third layer. Photosensitizing dyes having different absorption wavelengths may be adsorbed on each layer, such as adsorbing.

  A colorless compound may be co-adsorbed for the purpose of suppressing interaction such as association and aggregation between photosensitizing dyes. Examples of the hydrophobic compound to be co-adsorbed include a steroid compound having a carboxyl group (for example, chenodeoxycholic acid). Further, for the purpose of accelerating the removal of excess dye, the surface of the semiconductor fine particles may be treated with amines after adsorbing the dye. Examples of preferable amines include pyridine, 4-tert-butylpyridine, and polyvinylpyridine. When these are liquids, they may be used as they are, or when they are solids, they may be dissolved in an organic solvent.

Examples of the electrolyte contained in the charge transfer layer of the present invention include a combination of I ₂ and various iodides, a combination of Br ₂ and various bromides, a combination of ferrocyanate-ferricyanate metal complexes, Examples include combinations of metal complexes of ferrocene-ferricinium ions, combinations of sulfur compounds of alkyl thiol-alkyl disulfides, combinations of alkyl viologens and reduced forms thereof, combinations of polyhydroxybenzenes and oxidized forms thereof.
Here, examples of the iodide that can be combined with I ₂ include metal iodides such as LiI, NaI, KI, CsI, and CaI ₂ ; 1-propyl-3-methylimidazolium iodide, 1-propyl-2,3 -Iodine salts of quaternary imidazolium compounds such as dimethyl imidazolium iodide; iodine salts of quaternary pyridinium compounds; iodine salts of tetraalkylammonium compounds.
Examples of iodides that can be combined with Br ₂ include metal bromides such as LiBr, NaBr, KBr, CsBr, and CaBr ₂ ; bromine salts of quaternary ammonium compounds such as tetraalkylammonium bromide and pyridinium bromide, and the like.
Examples of alkyl viologen include methyl viologen chloride, hexyl viologen bromide, and benzyl viologen tetrafluoroborate. Examples of polyhydroxybenzenes include hydroquinone and naphthohydroquinone.
Among them, the electrolyte is preferably a combination of I ₂ and iodide, and in particular, from metal iodide, iodine salt of quaternary imidazolium compound, iodine salt of quaternary pyridinium compound, and iodine salt of tetraalkylammonium compound. A combination of at least one iodide selected from the group and I ₂ is preferred.

When the photoelectrochemical cell of the present invention is wet, the charge transfer layer contains an electrolyte. Examples of the electrolytic solution include water and an organic solvent that dissolves the electrolyte.
Examples of the organic solvent include nitrile solvents such as acetonitrile, methoxyacetonitrile, and propionitrile; carbonate solvents such as ethylene carbonate and propylene carbonate; lactone solvents such as γ-butyrolactone; amides such as N, N-dimethylformamide Ionic liquids such as 1-methyl-3-propylimidazolium iodide and 1-methyl-3-hexylimidazolium iodide; 1-ethyl-3-methylimidazolium-bis (trifluoromethanesulfonic acid) imide Is mentioned.
The electrolytic solution may be gelled with a polyacrylonitrile, polyvinylidene fluoride, poly-4-vinylpyridine, or a low-molecular gelling agent shown in Chemistry Letters, 1241 (1998).

When the photoelectrochemical cell of the present invention is dry, a solid electrolytic layer such as a solid hole transport material is used for the charge transfer layer.
Examples of solid hole transport materials include those made of p-type inorganic semiconductors containing monovalent copper such as CuI and CuSCN, and those shown in Synthetic Metal, 89 , 215 (1997) and Nature, 395 , 583 (1998). Aromatic amines; Polythiophene and its derivatives; Polypyrrole and its derivatives; Polyaniline and its derivatives; Poly (p-phenylene) and its derivatives; Conductive polymers such as poly (p-phenylene vinylene) and its derivatives Etc.
In order to prevent leakage and transpiration of the electrolyte, the photoelectric conversion element of the present invention is usually sealed using a sealing material (10). Examples of the sealing material include ionomer resins such as Himiran (Mitsui DuPont Polychemical); glass frit; hot melt adhesives such as SX1170 (Solaronix); adhesives such as Amosil 4 (Solaronix); BYNEL (DuPont) Manufactured), EVOH, PVA, lead-containing glass frit, vanadium-containing glass frit, bismuth-containing glass frit, zinc-containing glass frit, and the like.
From the viewpoint of hermeticity of the electrolytic solution, it is preferable to use a glass frit containing lead, vanadium, bismuth, zinc or the like as a sealing material.

The sealant for sealing the tip and / or the inside of the tube used in the present invention contains glass frit containing at least one of lead, vanadium, bismuth or zinc, and seals the glass frit. When used as a stopper, when a volatile solvent such as acetonitrile or iodine is used as the electrolytic solution, the durability is remarkably improved because they are difficult to volatilize particularly at high temperatures.
Examples of the composition of the glass frit containing lead include a mixture of PbO and at least one of B ₂ O ₃ , Na ₂ O, BaO, and SiO ₂ . An example is LS-0118 (manufactured by Nippon Electric Glass Co., Ltd.).
Examples of the composition of the glass frit containing vanadium include a mixture of at least one of ZnO, BaO, P ₂ O ₅ , and TeO ₂ and V ₂ O ₅ . Examples thereof include YEV8-3111, YEV3-4003, and YEV8-3018 (manufactured by Yamato Electronics Co., Ltd.).
Examples of the composition of the glass frit containing bismuth include a mixed system containing at least one of ZnO and P ₂ O ₅ and Bi ₂ O ₃ . An example is ABG-GP-068 (manufactured by TOMATEC). In addition to ZnO and P ₂ O ₅ , components such as B ₂ O ₃ , BaO, CuO, Al ₂ O ₃ , SrO, SiO ₂ , TiO ₂ , Li ₂ O, Na ₂ O, K ₂ O are mixed. May be.
The composition of the glass frit containing zinc includes a mixture of ZnO and B ₂ O ₃ . In addition to B ₂ O ₃ , components such as SiO ₂ , Na ₂ O, Li ₂ O, NaF, P ₂ O ₅ , SnO, K ₂ O, Al ₂ O ₃ , ZrO ₂ , SrO may be mixed good.
These glass frits may contain zirconium silicate, alumina, titania, silica, pigments and the like as fillers.

These glass frits are heated and melted with a soldering iron, a laser, a muffle furnace or the like, and then applied to the tip and / or inside of the tube to be used for sealing.
A tube is mounted in the hole formed in the photoelectrochemical cell. The reason is that when the hole is sealed with a glass frit, the temperature is usually about 300 to 700 ° C. However, when the tip and / or the inner hole of the tube is sealed, heat is not easily transmitted to the electrolyte part. This is because it is difficult to evaporate. When applying the glass frit to the tip and / or the inside of the tube, the tube may be applied while being cooled with cold air, a refrigerant, a metal clip, a coil, or the like. The length of the tube may be such that heat to the electrolyte part is not transmitted.
The inside of the tube attached to the hole formed in the photoelectrochemical cell is preferably prefilled with glass, adhesive, ceramics, cotton or the like. The reason for this is that when the tip and / or the inside of the tube is sealed with a glass frit after sealing the electrolyte, the filling prevents the electrolyte vapor from evaporating and the safety is further enhanced. is there. This filling is preferably grounded to the photoelectrochemical cell body so that the electrolyte does not penetrate into the tube. This is because when the photoelectrochemical cell is used, if the electrolytic solution penetrates into the space of the tube, the photoelectrochemical cell may not operate normally.
Examples of the glass filling the tube include glass rods and glass beads. As the adhesive, epoxy-based adhesive, acrylic-based, silicon-based adhesive that cures at heat or room temperature, or UV-curable adhesive can be used. As ceramics, zirconia beads or the like can be used. As the cotton, glass wool, absorbent cotton or the like can be used. When cotton is used, it is preferable that the electrolyte is sufficiently wetted with an adhesive or the like in advance so that the electrolyte is not absorbed by the cotton.
The tube attached to the hole formed in the photoelectrochemical cell is preferably made of an inorganic substance such as glass and / or ceramics. This is because these inorganic substances have high hermeticity and durability, and withstand high temperatures when the tip and / or the inside of the tube is sealed with glass frit.

  EXAMPLES Next, although an Example etc. are given and this invention is demonstrated further in detail, this invention is not limited by these examples.

Example 1
A glass frit paste (grade name: YEV3-) containing vanadium as a sealant around the conductive surface of conductive glass with tin oxide film doped with fluorine (made by Nippon Sheet Glass, 10Ω / □), which is a conductive substrate 4003, manufactured by Yamato Electronics Co., Ltd.) was applied with a dispenser. A hole was drilled in advance, and a conductive glass with a tin oxide film doped with fluorine on which a glass tube was mounted was superposed and fired at 490 ° C. From the glass tube to the electrolyte (solvent is acetonitrile; the iodine concentration in the solvent is 0.05 mol / liter, the lithium iodide concentration is also 0.1 mol / liter, and the 4-t-butylpyridine concentration is 0.5 mol / liter. 1-propyl-2,3-dimethylimidazolium iodide concentration was 0.6 mol / liter) was injected into the cell. Thereafter, one zirconia bead was put in the glass tube so that the adhesive and the electrolyte were not mixed. Thereafter, an epoxy adhesive EPOTEK353ND (manufactured by Epoxy Technology) was put into the glass tube, a glass rod was inserted into the glass tube, and the inside of the tube was filled with a filler. After the adhesive was cured, lead-containing glass frit (LS-0118, manufactured by Nippon Electric Glass Co., Ltd.) was applied to the tip of the glass tube and a part of the glass tube with a soldering iron to obtain a sealed cell.
The cell in which the electrolyte solution was sealed was aged in an oven at 85 ° C., and the change with time of iodine was measured at an absorbance of 362 nm. Table 1 shows the absorbance retention after 330 hours when the initial absorbance is 1. It means that the higher the absorbance, the higher the retention rate of iodine encapsulated in the photoelectrochemical cell.

(Comparative Example 1)
A cell was prepared in the same manner as in Example 1 except that the glass tube standing on the hole was not used and EVOH and a glass plate were used as the sealant and sealed by hot press. Subsequently, the time-dependent change of iodine was measured in the same manner as in Example 1. The results are shown in Table 1.

(Example 2)
Titanium oxide dispersion on conductive surface of conductive glass with tin oxide film doped with fluorine (made by Nippon Sheet Glass, 10Ω / □, linear expansion coefficient: 8.5 × 10 ^-6 / ° C), which is a conductive substrate Ti-Nanoxide T / SP (trade name, manufactured by Solaronix) was applied using screen printing, then baked at 500 ° C., and the glass was cooled to form a semiconductor fine particle layer on the conductive substrate. Glass frit paste (grade name: YEV3-4003, Yamato Electronics Co., Ltd.) containing vanadium as a sealant around fluorine-doped conductive glass with tin oxide film formed by TiO2 (manufactured by Nippon Sheet Glass, 10Ω / □) Manufactured by a dispenser. A hole was drilled in advance, and a conductive glass with a tin oxide film doped with fluorine on which a glass tube was mounted was superposed and fired at 490 ° C. Introduced a solution of cis-bis (isothiocyanate) (2,2'-bipyridyl-4,4'-dicarboxylate) (2,2'-bipyridyl-4,4'-dinonyl) ruthenium (II) into the cell The titanium oxide layer was dyed with a sensitizing dye. After injecting the electrolyte (Iodolyte R-150 (Solaronix)) from the glass tube into the cell, the epoxy adhesive EPOTEK353ND (Epoxy Technology) is placed in the glass tube so that the adhesive and the electrolyte are difficult to mix. The absorbent cotton sufficiently moistened with was put to the base of the glass tube. Thereafter, an epoxy adhesive EPOTEK353ND (manufactured by Epoxy Technology) was put into the glass tube, a glass rod was inserted into the glass tube, and the inside of the tube was filled with a filler. After the adhesive was cured, lead-containing glass frit (LS-0118, manufactured by Nippon Electric Glass Co., Ltd.) was applied to the tip of the glass tube and a part of the glass tube with a soldering iron to obtain a sealed cell.
The sealed cell thus prepared is put into a xenon weathering tester and irradiated with light (light intensity: 0.48 W / m ² (340 nm), black panel temperature: 83 ° C., humidity: 50% RH, no rain) The change in conversion efficiency over time was observed. The conversion efficiency was measured using a solar simulator manufactured by Yamashita Denso.
Table 2 shows the retention of conversion efficiency after 24 hours when the initial efficiency is 1.

(Comparative Example 2)
A cell was prepared in the same manner as in Example 1 except that the glass tube standing on the hole was not used and EVOH and a glass plate were used as the sealant and sealed by hot press. Subsequently, the time-dependent change of iodine was measured in the same manner as in Example 1. The results are shown in Table 2.

  The photoelectrochemical cell of the present invention can be sealed safely compared to conventional sealing methods, and the loss of electrolytes such as iodine and volatile solvents can be achieved even at high temperatures and for long periods of use. Since it is remarkably reduced, it has excellent durability. Because of such excellent characteristics, it can be used in solar cells using sunlight, photoelectrochemical cells using artificial light in tunnels and indoors. In addition, the photoelectrochemical cell of the present invention can be used as an optical sensor because current flows upon receiving light irradiation.

It is a cross-sectional schematic diagram of the wet photoelectrochemistry of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Conductive layer 3 Semiconductor particle layer 4 Photosensitizing dye 5 Electrolyte 6 Conductive layer 7 Substrate 8 Conductive substrate 9 Counter electrode 10 Sealant 11 Tube

Claims (5)

  A hole provided in a photoelectrochemical cell in a photoelectrochemical cell in which a laminate including a conductive substrate, semiconductor fine particles adsorbing a photosensitizing dye, a charge transfer layer, and a counter electrode is sealed with a sealant A tube is attached to the tube, and the tip and / or the inside of the tube is sealed with a glass frit.   2. The photoelectrochemical cell according to claim 1, wherein the tube is filled with a filler and then sealed with a glass frit.   The photoelectrochemical cell according to claim 2, wherein the filler is one or more selected from glass, an adhesive, ceramics, and cotton.   The photoelectrochemical cell according to any one of claims 1 to 3, wherein the tube is made of glass and / or ceramics.   The photoelectrochemical cell according to any one of claims 2 to 4, wherein the filler is in contact with the photoelectrochemical cell.

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