JPH11273753A - Coloring matter sensitizing type photocell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coloring matter sensitizing type photocell (a solar cell for example) capable of enhancing photoelectric conversion efficiency and increasing power supply amount per unit area. SOLUTION: A photoelectric conversion layer 10a formed by stacking an electrode layer 11a, a semiconductor layer 12a made of metal oxide in which a photo sensitizing coloring matter 13a is adsorbed, an electrolyte layer 14a, and an electrode layer 15a in order, and a photoelectric conversion layer 10b formed by stacking an electrode layer 11b, a semiconductor layer 12b made of metal oxide in which a photo sensitizing coloring matter 13b is adsorbed, an electrolyte layer 14b, and an electrode layer 15b in order are alternately stacked in at least two layers on each side of a light transmitting insulating substrate 20. The electrode layer 15b on the opposite side the most distant from the light incident side (the arrow direction) is preferable to be composed of a reflective electrode layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dye-sensitized photocell with improved photoelectric conversion efficiency.

[0002]

2. Description of the Related Art As a photovoltaic cell such as a solar cell, a Pn junction photocell using a silicon semiconductor is widely used.

[0003] The silicon semiconductor used in such a photovoltaic cell must be highly pure and regular in order to increase the photoelectric conversion efficiency of the photovoltaic cell. However, manufacturing a silicon semiconductor and a photovoltaic cell requires a great deal of energy, and increases the manufacturing cost. Further, in a solar cell using such a silicon semiconductor, the photoelectric conversion efficiency sharply decreases under conditions of non-direct sunlight or cloudy weather.

Therefore, for example, Japanese Patent Application Laid-Open No. Hei.
The publication discloses a dye-sensitized photovoltaic cell (for example, using a material in which a photosensitizing dye such as a ruthenium metal complex is adsorbed on a porous semiconductor made of a metal oxide such as crystalline titanium oxide). Solar cells) have been proposed.

The above dye-sensitized photovoltaic cell is, specifically,
As shown in FIG. 3, an insulating substrate 17 such as a transparent glass plate is used.
An electrode substrate formed by forming a transparent electrode layer 11 on which a semiconductor layer 12 having the photosensitizing dye 13 adsorbed thereon as described above is formed as a working electrode, and a counter electrode such as a transparent glass plate. It is manufactured by using an electrode substrate formed by forming a transparent electrode layer 15 on a simple insulating substrate 16 and sealing an electrolyte solution between these electrodes.

[0006]

The dye-sensitized photovoltaic cell of this kind proposed in the prior art can be obtained by appropriately selecting each material layer.
The photoelectric conversion efficiency reaches about 7%, the corrosion resistance is good, and the life is relatively high, which is estimated to be about 20 years.

However, the photoelectric conversion efficiency is still not sufficient. For example, in order to install solar cells on a roof or the like and supply sufficient electric power, the installation area must be sufficiently large. However, the installation area is limited, and the amount of power supply per unit area needs to be increased.

The present invention solves the above problems,
An object of the present invention is to provide a dye-sensitized photovoltaic cell (for example, a solar cell) in which the photoelectric conversion efficiency is improved and the power supply amount per unit area is increased.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, there are provided an electrode layer, a semiconductor layer made of a metal oxide to which a photosensitizing dye is adsorbed, an electrolyte layer, and an electrode layer. A dye-sensitized photovoltaic cell is provided, in which at least two photoelectric conversion layers that are sequentially stacked are alternately stacked with a light-transmitting insulating substrate interposed therebetween.

[0010] In the invention according to claim 2, the dye-sensitized photovoltaic cell according to claim 1, wherein the electrode layer farthest away from the light incident side is a reflective electrode layer. Provided.

According to a third aspect of the present invention, there is provided the dye-sensitized photovoltaic cell according to the second aspect, wherein the reflective electrode layer is made of a corrosion-resistant conductive metal.

In the invention according to claim 4, the photosensitizing dye is:
The dye-sensitized photovoltaic cell according to any one of claims 1 to 3, comprising a ruthenium metal complex.

In the invention according to claim 5, the metal oxide is:
3. The method according to claim 1, wherein the material is made of titanium oxide.
3. A dye-sensitized photovoltaic cell according to any one of items 3 and 4.

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view showing an example of the dye-sensitized photocell of the present invention. In FIG. 1, 10a and 10b are photoelectric conversion layers, and the photoelectric conversion layer 10a is an electrode layer 11
a, a semiconductor layer 12a made of a metal oxide to which a photosensitizing dye 13a is adsorbed, an electrolyte layer 14a, and an electrode layer 15a. In addition, the photoelectric conversion layer 10b includes the electrode layer 11
and a semiconductor layer 12b made of a metal oxide adsorbing the photosensitizing dye 13b, an electrolyte layer 14b, and an electrode layer 15b.

The photoelectric conversion layer 10a and the photoelectric conversion layer 10b are alternately stacked with the light-transmitting insulating substrate 20 interposed therebetween, thereby forming the dye-sensitized photocell A of the present invention. I have. 20a and 20b are light-transmitting insulating substrates, which are provided to support the electrode layers 11a and 11b and to protect the electrode layers 11a and 11b.

The insulating substrates 20, 20a and 20b are
In order to transmit light sufficiently, generally, a transparent glass plate such as float glass or polyester (PET),
A transparent plastic plate such as polycarbonate (having a total light transmittance of 60% or more, preferably 85% or more) is used. Note that the insulating substrate 20b on the opposite side (back side) farthest from the light incident side (front side) does not need to transmit light, so that an opaque glass plate, plastic plate, ceramic plate, or metal plate is used. Is also good.

The electrode layers 11a and 11b constituting the photoelectric conversion layers 10a and 10b are usually formed of insulating substrates 20a and 20b.
b is formed on the surface. In addition, the photoelectric conversion layers 10a, 10
The electrode layers 15a and 15b constituting b are usually formed on the surface of the insulating substrate 20. These electrode layers 11a, 15
Generally, a, 11b, and 15b are transparent conductive layers in order to sufficiently transmit light.

As such a transparent conductive layer, tin oxide (TCO) and tin oxide doped with fluorine (TCC) are mainly used.
O), indium oxide (ICO), tin oxide doped with fluorine (TCO), indium oxide doped with tin oxide (ITO), tin oxide doped with antimony (AT
O), aluminum oxide-doped zinc oxide (AZO), etc., having a total light transmittance of 60% or more, preferably 85% or more, and a surface resistance of 10 Ω / cm ² or less are used. Since the electrode layer 11b on the opposite side (back side) farthest from the light incident side (front side) does not need to transmit light, an opaque conductive layer or a conductive metal plate may be used.

In particular, the electrode layer 11b on the opposite side farthest from the light incident side is preferably made of a reflective electrode layer. Such reflective electrode layers include platinum, gold,
Corrosion resistant metals such as silver, titanium, vanadium, chromium, zirconium, niobium, molybdenum, palladium, tantalum, tungsten, palladium (80% by weight) -platinum (20% by weight), titanium (50% by weight) -zirconium (50%) %), Platinum (50% by weight) -gold (40% by weight) -palladium (10% by weight). Among them, platinum, gold and silver are preferred.
In particular, platinum is preferably used because it has excellent conductivity, reflectivity, and corrosion resistance and also acts as an electrode catalyst for increasing the reduction rate of the electron transfer mediator of the electrolyte layer in contact with the platinum.

On the insulating substrates 20a, 20b and 20, electrode layers 11a and 1 made of a transparent conductive layer or an opaque conductive layer are provided.
In order to form 5a, 11b, and 15b, a sputtering method, a vacuum evaporation method, and a chemical vapor deposition method (CVD method) are mainly used. Further, a solution containing a metal salt or an organometallic compound capable of forming a transparent conductive layer or an opaque conductive layer is applied on an insulating substrate, dried, and heat-treated such as baking or irradiated with electromagnetic waves such as active rays. You can also.

The electrode layers 11a, 15a, 11b, 1
As 5b, a transparent conductive glass plate having a tin oxide-doped indium oxide (ITO) film formed on a transparent glass plate, and a transparent glass plate having a fluorine-doped tin oxide (TCO) film formed on the transparent glass plate A conductive glass plate is commercially available, and such a transparent conductive glass plate may be used.

The semiconductor layer 12 made of a metal oxide
As a and 12b, known semiconductors such as titanium oxide, zinc oxide, niobium oxide, tungsten oxide, barium titanate, strontium titanate, and cadmium sulfide are used. In particular, a semiconductor made of titanium oxide is preferable from the viewpoint of good semiconductor characteristics and corrosion resistance, stability and safety.

The semiconductor layer 12a made of the above metal oxide,
12b is usually formed by forming a semiconductor precursor on a transparent conductive layer or an opaque conductive layer formed on the insulating substrates 20a, 20b and 20 and heating or baking the semiconductor precursor or irradiating it with ultraviolet rays. .

The term "semiconductor precursor" as used herein means a state before a finally obtained semiconductor, and a metal alkoxide and a condensate thereof, a metal complex, and a metal organic compound capable of forming a semiconductor composed of the above metal oxide. Semiconductor precursors formed by hydrolyzing and drying a solution containing at least one compound selected from acid salts are preferred.

For example, when a semiconductor comprising titanium oxide is to be obtained, a metal alkoxide such as titanium ethoxide and titanium tetraisopropoxide, and a hydrolytic polycondensation of such a metal alkoxide are used as the semiconductor precursor. A condensate or a metal complex such as titanium acetylacetonate or a metal organic acid salt such as titanium octylate is used as a raw material, and a solution formed by hydrolyzing and drying these solutions is used. (Sol-gel method).

As another semiconductor precursor, a suspension in which colloids or fine particles of a semiconductor capable of forming a semiconductor made of the above-described metal oxide, for example, colloids or fine particles of a metal oxide such as titanium oxide, are applied. A dried product (colloidal method) or a product obtained by forming a semiconductor precursor film by a physical vapor deposition method, a vapor deposition method, an electrodeposition method, or the like is used.

When a metal alkoxide is used as a semiconductor precursor, the metal alkoxide is hydrolyzed in an alcohol solvent such as methanol or ethanol, and this is hydrolyzed by spin coating or dip coating to a substrate such as an insulating substrate. A semiconductor precursor layer is formed by coating and drying on the transparent conductive layer formed in step (1). In addition, in order to improve the wetting when applied and to prevent cracking, a nonionic surfactant such as polyoxyethylene alkyl ether or polyethylene glycol fatty acid ester, and a binder such as polyethylene oxide or polyethylene glycol may be used. It is preferable to add about 40% by weight.

Thereafter, in the case of a semiconductor precursor of titanium oxide, the precursor is heated and baked at about 450 ° C. to 600 ° C. for about 30 minutes to 1 hour, or an irradiation dose of 50 mJ / cm ² to 2 hours.
By irradiating ultraviolet rays of about J / cm ² , a film-like porous semiconductor layer made of crystalline titanium oxide is formed. The reaction, sintering, crystallization, and the like of the semiconductor precursor are promoted by such heating and firing conditions or ultraviolet irradiation conditions, and the final metal oxide is formed on the transparent conductive layer formed on the insulating substrate. A semiconductor layer is formed. The thickness of the semiconductor layer is generally 5 to 50 μm, preferably 10 to 2 μm.
0 μm.

Here, the roughness factor (surface roughness coefficient) of the semiconductor layer made of a metal oxide such as titanium oxide.
Usually, the thing of 10-1000 is used. The roughness factor (surface roughness coefficient) is represented by the ratio of the actual surface area of the semiconductor layer / the surface area of the semiconductor layer.

In particular, the semiconductor precursor layer formed by hydrolyzing and drying a solution containing at least one compound selected from metal alkoxides and condensates thereof, metal complexes, and metal organic acid salts is used as the semiconductor precursor layer. Use of such a material has advantages in that the composition of the obtained semiconductor layer becomes uniform, the crystal size becomes small, and current flows easily.

The photosensitizing dyes 13a and 13b are charged on the surface regions of the semiconductor layers 12a and 12b made of the metal oxide in order to improve the sensitivity to light (eg, sunlight) at the time of photoelectric conversion. Adsorbed as a carrier. As such photosensitizing dyes 13a and 13b, those having absorption in a visible light region and / or an infrared light region, and a metal complex and an organic dye are used.

Examples of the metal complex include metal complexes such as ruthenium, osmium, iron and zinc, metal phthalocyanines such as copper phthalocyanine and titanyl phthalocyanine, chlorophyll derivatives, and hemin. These metal complexes are preferable because of their excellent photosensitizing effect and durability. In particular, good results are obtained with ruthenium metal complexes.

Specific examples of the ruthenium metal complex include R
uL ₂ (CN) ₂ , RuL ₂ (SCN) ₂ , RuL
₂ (H ₂ O) ₂ and RuL ₃ (CN). Here, L is 2,2'-bipyridyl-4,4'-dicarboxylate and the like, for example, ruthenium-cis-dicyano-bis (2,2'-bipyridyl-4,4 '
-Dicarboxylate, ruthenium-cis-dithiocyano-bis (2,2'-bipyridyl-4,4'-dicarboxylate, ruthenium-cis-diaqua-bis (2,
2'-Bipyridyl-4,4'-dicarboxylate and ruthenium-cyano-tris (2,2'-bipyridyl-
4,4'-dicarboxylate and the like are preferably used.

Examples of the organic dyes include metal-free phthalocyanine, cyanine dyes (such as NK1194 and NK3422 manufactured by Nippon Kogaku Dye Laboratories), and merocyanine dyes (NK2426 and NK25 made by Nippon Kogaku Dye Laboratory).
01, etc.), xanthene dyes (uranin, eosin,
Rose bengal, rhodamine B, dibromofluorescein, etc.), and triphenylmethane-based dyes (malachite green, crystal violet, etc.).

In particular, those having a functional group such as a carboxyl group, a carboxyalkyl group, a hydroxyl group, a hydroxyalkyl group, a sulfone group, and a carboxyalkyl group in the molecule are preferable because good adsorption is performed.

Semiconductor layers 12a and 12 made of metal oxide
To adsorb the photosensitizing dyes 13a and 13b on b,
A known method is adopted. For example, the photosensitizing dye is dissolved in a solvent such as ethanol, toluene, or dimethylformamide, and the solution is applied on the semiconductor layer and dried to adsorb the photosensitizing dye. The photosensitizing dye is chemisorbed or simply adsorbed on the surface area of the semiconductor. Alternatively, the substrate on which the semiconductor layer is formed can be adsorbed by heating and refluxing the solution at the boiling point of the solvent in the solution of the photosensitizing dye.

As the electrolyte layers 14a and 14b,
Usually, an electrolyte solution is used. In addition, a gel or solid electrolyte can also be used. The electrolyte solution is not particularly limited, and examples thereof include a solution containing a redox system (redox pair) such as I ⁻ / I ₃ ⁻ , Br ⁻ / Br ₃ ⁻ , and quinone / hydroquinone, and a transition metal complex solution that transports electrons. . Specifically, in the case of I ⁻ / I ₃ ⁻ , a solution in which iodine and an ammonium salt of iodine are dissolved in a solvent such as acetonitrile, ethylene carbonate, propylene carbonate, or ethanol is used. The thickness of the electrolyte layer is generally 1 to 50.
μm.

In order to form such electrolyte layers 14a and 14b, usually, the semiconductor layer 12a adsorbing the photosensitizing dye 13b and the electrode layer 15a and the semiconductor layer 12b adsorbing the photosensitizing dye 13b are formed. An electrolyte solution is put between the electrode layers 15b, and the side surfaces are sealed with a sealing agent such as an epoxy thermosetting resin, an acrylic ultraviolet curing resin, or water glass.

Thus, the photoelectric conversion layers 10a and 10b
However, the dye-sensitized photocell A of the present invention is formed by alternately laminating two layers with the light-transmitting insulating substrate 20 interposed therebetween.
In this case, light (such as sunlight) is incident from the front side indicated by the arrow.

The photoelectric conversion layer 10a and the photoelectric conversion layer 10
b, the front and back are arranged in opposite directions, but the photoelectric conversion layers 10a and 10b may be arranged in any direction. Also, the insulating substrate 20 on the opposite side (back side) farthest from the incident side (front side) of light (sunlight or the like).
When b or the electrode layer 11b is light-transmitting, light (such as sunlight) can be incident from the back side. In addition, the photoelectric conversion layer is not limited to a structure in which two layers are alternately laminated with a light-transmitting insulating substrate interposed therebetween, and three or more layers may be alternately laminated.

FIG. 2 is a sectional view showing another example of the dye-sensitized photocell of the present invention. In FIG. 2, 10a, 10b,
10c and 10d are photoelectric conversion layers, and the photoelectric conversion layer 1
No. 0a is formed by laminating an electrode layer 11a, a semiconductor layer 12a made of a metal oxide adsorbing the photosensitizing dye 13a, an electrolyte layer 14a, and an electrode layer 15a in this order. In addition, the photoelectric conversion layer 1
No. 0b is formed by laminating an electrode layer 11b, a semiconductor layer 12b made of a metal oxide adsorbing the photosensitizing dye 13b, an electrolyte layer 14b, and an electrode layer 15b in this order.

Further, the photoelectric conversion layer 10c comprises an electrode layer 11c.
And a semiconductor layer 12c made of a metal oxide to which a photosensitizing dye 13c is adsorbed, an electrolyte layer 14c, and an electrode layer 15c. In addition, the photoelectric conversion layer 10d includes an electrode layer 11d.
And a semiconductor layer 12d made of a metal oxide to which a photosensitizing dye 13d is adsorbed, an electrolyte layer 14d, and an electrode layer 15d.

The photoelectric conversion layer 10a, the photoelectric conversion layer 10b, the photoelectric conversion layer 10c, and the photoelectric conversion layer 10d are
The dye-sensitized photovoltaic cell B of the present invention is formed by alternately laminating four layers with the light-transmitting insulating substrate 20 interposed therebetween. 20a and 20b are light-transmitting insulating substrates, which are provided to support the electrode layers 11a and 11b and to protect the electrode layers 11a and 11b.

In each of the photoelectric conversion layers 10a, 10b, 10c and 10d, a method of forming each of the electrode layers 11a, 11b, 11c and 11d, and each of the photosensitizing dyes 13a, 13b and 13d
Semiconductor layer 1 made of metal oxide adsorbing c and 13d
The method of forming 2a, 12b, 12c and 12d, the method of forming each of the electrolyte layers 14a, 14b, 14c and 14d, and the method of forming each of the electrode layers 15a, 15b, 15c and 15d are the same as those described in the description of FIG. Since it is performed in the same manner as described above, the description is omitted here.

The photoelectric conversion layer 10a and the photoelectric conversion layer 10
b, the photoelectric conversion layer 10c, and the photoelectric conversion layer 10d are all arranged in the same direction on the front and back, but these photoelectric conversion layers 10a, 10b, 10c, and 10d are arranged in any direction on the front and back. May be. Further, when the insulating substrate 20d or the electrode layer 11d on the opposite side (back side) farthest from the incident side (front side) of the light (sunlight or the like) is light transmissive, light (sunlight or the like) is incident from the back side. You can do it too.

(Function) In the dye-sensitized photocells (solar cells) A and B of the present invention thus constituted, when light (sunlight) is irradiated from the direction of the arrow, the photosensitizing dye 13
a, 13b, 13c and 13d absorb and excite light in the visible region. Electrons generated by this excitation are injected into the semiconductor layers 12a, 12b, 12c and 12d, and then the electrode layers 11a, 11b, 11c and 11 serving as working electrodes.
Move to d.

The electrode layers 11a, 11b, 11
The electrons that have moved to c and 11d are applied to the electrode layers 11a and 11d.
b, 11c, and 11d, lead wires (not shown), and electrode layers 15a, 15b, and 15 serving as counter electrodes.
Move to c and 15d. Then, this electrode layer 15a,
The electrons transferred to 15b, 15c and 15d reduce the redox system in the electrolyte solutions 14a, 14b, 14c and 14d.

On the other hand, photosensitizing dyes 13a, 13a having electrons transferred to semiconductor layers 12a, 12b, 12c, and 12d.
b, 13c and 13d are in an oxidized state, which is reduced by the redox system in the electrolyte solutions 14a, 14b, 14c and 14d and returns to the original state. In this way, electrons flow and function as a photovoltaic cell (solar cell).

Here, as in the dye-sensitized photovoltaic cell (solar cell) of the present invention, an electrode layer, a semiconductor layer made of a metal oxide to which a photosensitizing dye is adsorbed, an electrolyte layer, and an electrode layer are laminated in this order. Photoelectric conversion layer, sandwiching a light-transmitting insulating substrate,
When at least two layers are alternately stacked, light (sunlight) incident from the front side passes through each photoelectric conversion layer from the surface side to the opposite side, and thereby electrons are emitted to each photoelectric conversion layer. Flow, and each photoelectric conversion layer acts as a photovoltaic cell (solar cell).

Therefore, light (sunlight) not absorbed by the first photoelectric conversion layer (10a) is transmitted to the next photoelectric conversion layer (1a).
0b). Further, the light (sunlight) not absorbed is absorbed by the next photoelectric conversion layer (10c). Further, the light (sunlight) that has not been absorbed is absorbed by the next photoelectric conversion layer (10d). Therefore, according to the dye-sensitized photovoltaic cell (solar cell) of the present invention, the utilization efficiency of light (sunlight) increases, and the photoelectric conversion efficiency improves.

In particular, when the opposite electrode layer farthest from the light (sunlight) incident side is formed of a reflective electrode layer,
Light (sunlight) transmitted through each photoelectric conversion layer is reflected by this reflective electrode layer, and follows each photoelectric conversion layer in a reverse path from the opposite side to the surface side. Is absorbed by. Therefore, the use efficiency of light (sunlight) is further increased, and the photoelectric conversion efficiency is further improved.

[0052]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The advantages of the present invention will be described below with reference to examples and comparative examples of the present invention. Example 1 In this example, a photovoltaic cell A as shown in FIG. 1 is manufactured. <Production of Electrode Layers 11a and 11b and 15a and 15b> A commercially available transparent conductive glass plate (11a) having a fluorine-doped tin oxide layer 11a formed on one surface of a transparent glass plate 20a.
/ 20a) (1 cm square) was prepared. Separately, a reflective conductive glass plate (11b / 20b) (1 cm square) having a 0.3 μm-thick platinum layer 11b formed on one surface of a transparent glass plate 20b by a sputtering method was prepared.

Separately, a commercially available transparent conductive glass plate (15a / 20) in which tin oxide layers 15a and 15b doped with fluorine are formed on both surfaces of the transparent glass plate 20 separately.
/ 15b) (1 cm square) was prepared. The transparent conductive glass plate (15a / 20 / 15b) is used in combination as the light-transmitting insulating substrate 20. <Formation of Titanium Semiconductor Layers 12a and 12b> The titanium oxide semiconductor layers 12a are formed on the surface of the transparent conductive glass plate (11a / 20a) by the following method.
Was formed to produce a transparent conductive glass plate (12a / 11a / 20a) having the titanium oxide semiconductor layer 12a.

Separately, a titanium oxide semiconductor layer 12b is formed on the surface of the platinum layer-doped tin oxide layer 11b of the reflective conductive glass plate (11b / 20b) by the same method. A transparent conductive glass plate having 12b (12b / 11b / 20b) was produced.

The method of forming the titanium oxide semiconductor layer is as follows: 25% by weight of titanium oxide powder (P-25 manufactured by Degussa)
And 5% by weight of a surfactant (polyoxyethylene oleyl ether (Neugen EA170 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
And 70% by weight of water were mixed and dispersed by a sand mill to prepare a titanium oxide dispersion. The average particle size of the titanium oxide particles in this titanium oxide dispersion was 200 μm.

To 100 parts by weight of this titanium oxide dispersion, polyethylene glycol (PEG4 manufactured by Sanyo Chemical Co., Ltd.) was used.
000S) 10% by weight of a 10% aqueous solution was added to adjust the viscosity, and the viscosity was adjusted with a bar coater to obtain a fluorine-doped tin oxide layer 1 of the transparent conductive glass plate (11a / 20a).
It was applied to the surface 1a and dried. This was placed in an electric furnace and heated and sintered at 450 ° C. for 30 minutes in air to form a semiconductor layer 12 a made of porous titanium oxide. The thickness of the semiconductor layer 12a was 10 μm, and the roughness factor (surface roughness coefficient) was 700.

Separately, a porous titanium oxide semiconductor layer 12b was formed in the same manner as described above, using the reflective conductive glass plate (11b / 20b). The thickness of the semiconductor layer 12b was 10 μm, and the roughness factor (surface roughness coefficient) was 700.

<Photosensitizing Dye 13 on Titanium Oxide Semiconductor Layer>
a, 13b> Before adsorbing the photosensitizing dye, the transparent conductive glass plate (12a
/ 11a / 20a) with 2 mol of titanium tetrachloride (Ti
After being immersed in an aqueous solution of Cl ₄ ) and allowed to stand overnight, it was heated in air at 450 ° C. for 30 minutes.

The transparent conductive glass plate (12a / 11a / 20a) on which the semiconductor layer 12a was formed was coated with a photosensitizing dye [ruthenium-cis-dithiocyano-bis (2,2)] comprising a ruthenium metal complex synthesized by the following method. 2'-bipyridyl-4,4'-dicarboxylate] 3 × 10 ^-4 m
ol immersed in ethanol solution for 3 hours, taken out,
After drying in the air, the deep red photosensitizing dye 13a was adsorbed on the surface area of the titanium oxide semiconductor layer 12a.

Separately, a reflective conductive glass plate (12b / 11b / 20b) on which the semiconductor layer 12b is formed
And a titanium oxide semiconductor layer 12
The deep red photosensitizing dye 13b was adsorbed on the surface area b.

The method for synthesizing the photosensitizing dye is as follows. RuL ₂ Cl ₂ .2H ₂ O (where L is
2,2'-bipyridyl-4,4'-dicarboxylate) is dissolved in dimethylformamide and sodium hydroxide is added. To this, an aqueous solution of sodium thiocyanate (NaSCN) dissolved in water is added and mixed, and the mixture is heated and refluxed in a nitrogen atmosphere for 6 hours to perform a reaction.

After cooling the obtained reaction solution, the solvent is evaporated, and the remaining solid (product) is dissolved in water and filtered. The filtrate was adjusted to Ph 2.5 with perchloric acid (HClO ₄ ), washed and dried to obtain the desired photosensitizing dye [ruthenium-cis-dithiocyano-bis (2,2′-bipyridyl-4,4 ′). -Dicarboxylate] was synthesized.

<Formation of Electrolyte Layers 14a and 14b> As an electrolyte solution, tetrapropylammonium iodide [(C ₃ H ₇ ) NI] and iodine were used at concentrations of 0.46 mol of the former and 0.06 mol of the latter, respectively. The electrolyte layers 14a and 14b were formed when a photovoltaic cell was manufactured by the following method using a solution dissolved in a mixed solvent of acetonitrile: ethylene oxide = 1: 4 (volume ratio). The thickness of each of the electrolyte layers 14a and 14b is 10 μm.

<Preparation of Photovoltaic Cell A> A transparent conductive glass plate (14a / 13b)
/ 12b / 11b / 20b) on a 1 mm wide frame.
An epoxy-based thermosetting adhesive (Struck Bond manufactured by Mitsui Toatsu Chemicals, Inc.) is applied, and the above-mentioned electrolyte solution 14b is dropped into a frame surrounded by the adhesive, and the transparent conductive glass plate ( 15a / 20 / 15b).

Further, the transparent conductive glass plate (15a)
/ 20 / 15b), an epoxy-based thermosetting adhesive (Structbond manufactured by Mitsui Toatsu Chemicals Co., Ltd.) was applied in a frame shape with a width of 1 mm, and the electrolyte was placed in a frame surrounded by the adhesive. The solution 14a was dropped, and a transparent conductive glass plate (14a / 13a /
12a / 11a / 20a) are laminated and bonded, and this is cured by heating in an oven at a temperature of 100 ° C. for 3 hours.
Photocell A was produced. In addition, a lead wire was attached to each electrode layer when producing the photovoltaic cell A.

In this photovoltaic cell A, as shown in FIG. 1, a photoelectric conversion layer 10a and a photoelectric conversion layer 10b are alternately laminated with a light-transmitting insulating substrate 20 interposed therebetween. Are light-transmitting insulating substrates 20a and 20b, respectively.
Protected by The light receiving area of the photocell A is 0.8 cm ² mm.

<Measurement of Performance of Photovoltaic Cell A> Lead wires of each electrode layer of the photovoltaic cell A were connected in parallel, and a solar simulator (A) was used with the photovoltaic cell A from the front side (in the direction of the arrow).
M1.5, 96 mW / cm ² ), and the battery performance was measured. As a result, the photoelectric conversion efficiency reached 13%, and the maximum power was 8.5 mW.

Example 2 In this example, a photovoltaic cell B as shown in FIG. 2 is manufactured. <Production of Various Substrates> A commercially available transparent conductive glass plate (15a / 20a) (1 cm square) having a fluorine-doped tin oxide layer 15a formed on one surface of a transparent glass plate 20a was prepared. Separately, a photosensitizing dye-adsorbed semiconductor is placed on a fluorine-doped tin oxide layer 11d of a commercially available transparent conductive glass plate (15d / 20d) in which a fluorine-doped tin oxide layer 11d is formed on one surface of a transparent glass plate 20b. Transparent conductive glass plate with layer (13d / 12d / 11d / 20d) (1 cm square)
Was prepared.

Further, a commercially available transparent conductive glass plate (15a / 20 / 15b) in which fluorine-doped tin oxide layers 11a and 15b are respectively formed on both surfaces of a transparent glass plate 20 is separately provided.
A transparent conductive glass plate (13d / 12a) having a semiconductor layer for photosensitizing dye adsorption on a fluorine-doped tin oxide layer 11a of
/ 11a / 20 / 15b) (1 cm square). Similarly, a transparent conductive glass plate (13b / 12b / 11b / 20/1) having a semiconductor layer for photosensitizing dye adsorption.
5c) (1 cm square) was prepared. Similarly, a transparent conductive glass plate (13b / 12b / 11b / 20 / 15c) having a semiconductor layer on which a photosensitizing dye is adsorbed (1 cm)
Corner) was prepared.

The formation of each semiconductor layer and the adsorption of the photosensitizing dye to each semiconductor layer were performed in the same manner as described in Example 1. The above-mentioned transparent conductive glass plates having the semiconductor layer adsorbing the photosensitizing dye are used together as the light-transmitting insulating substrate 20.

<Electrolyte layers 14a, 14b, 14c, 14
Formation of b> Tetrapropylammonium iodide [(C ₃ H ₇ ) NI] and iodine were used as an electrolyte solution.
Acetonitrile: ethylene oxide = 1: 4 so that the concentration becomes 0.46 mol of the former and 0.06 mol of the latter, respectively.
When a photovoltaic cell is manufactured by the following method using a solution dissolved in a mixed solvent (volume ratio), the electrolyte layers 14a, 14
b, 14c and 14b were formed. This electrolyte layer 14a,
The thickness of each of 14b, 14c and 14b is 10 μm.

<Preparation of Photovoltaic Cell B> A transparent conductive glass plate (13d / 12d) having a semiconductor layer adsorbing the above photosensitizing dye
/ 11d / 20d), an epoxy-based thermosetting adhesive (Structbond manufactured by Mitsui Toatsu Chemicals, Inc.) was applied in a frame shape with a width of 1 mm, and the electrolyte was placed in a frame surrounded by the adhesive. A solution 14d was dropped, and a transparent conductive glass plate (13c / 12c /
11c / 20 / 15d).

Further, the transparent conductive glass plate (13b / 12b / 11b /
20 / 15c), an epoxy-based thermosetting adhesive (Struct Bond manufactured by Mitsui Toatsu Chemical Co., Ltd.) in a 1 mm wide frame
Is applied, and the electrolyte solution 14c is dropped into a frame surrounded by the adhesive, and a transparent conductive glass plate (13b / 12b / 11) having a semiconductor layer for adsorbing the photosensitizing dye is added thereto.
b / 20 / 15c).

Further, a transparent conductive glass plate (13b / 12b / 11b /
20 / 15c), an epoxy-based thermosetting adhesive (Strucbond manufactured by Mitsui Toatsu Chemicals, Inc.) is applied in a 1 mm wide frame shape, and the electrolyte solution is placed in a frame surrounded by the adhesive. 14b is dropped, and a transparent conductive glass plate (13a / 12a / 11a) having a semiconductor layer for adsorbing the photosensitizing dye is dropped thereon.
/ 20 / 15b) were laminated and laminated.

Further, a transparent conductive glass plate (13a / 12a / 11a /
20 / 15b) An epoxy-based thermosetting adhesive (Struct Bond manufactured by Mitsui Toatsu Chemicals Co., Ltd.) on a 1 mm wide frame
Is applied, and the electrolyte solution 14a is dropped into a frame surrounded by the adhesive, and the transparent conductive glass plate (15a / 15a / 15a / 15a) is formed by forming a fluorine-doped tin oxide layer 15a on one surface of the transparent glass plate 20a. 20a) was overlaid and bonded, and this was heated and cured in an oven at a temperature of 100 ° C. for 3 hours to produce a photovoltaic cell B. In addition, a lead wire was attached to each electrode layer when producing the photovoltaic cell B.

As shown in FIG. 2, this photovoltaic cell B has four photoelectric conversion layers 10a, 10b, 10c, and 10d sandwiching each light-transmitting insulating substrate 20. They are alternately laminated, and the front and back surfaces thereof are protected by light-transmitting insulating substrates 20a and 20d, respectively. The light receiving area of the photocell B is 0.8c.
m ² .

<Measurement of Performance of Photovoltaic Cell B> Lead wires of each electrode layer of the photovoltaic cell B were connected in parallel, and a solar simulator (A) was used with the photovoltaic cell B from the front side (in the direction of the arrow).
M1.5, 96 mW / cm ² ), the battery performance was measured. The photoelectric conversion efficiency reached 13%, and the maximum power was 10.5 mW. The photovoltaic cell B was provided with a solar simulator (AM 1.5, 96 mW /
cm ² ), the battery performance was the same as above when the battery performance was measured.

(Example 3) In Example 1, the semiconductor layer 12b on which the photosensitizing dye 13b was adsorbed was formed on the surface of the fluorine-doped tin oxide layer 15b. Thus, a photovoltaic cell C was produced. The photoelectric conversion efficiency of this photovoltaic cell C reached 12%, and the maximum power was 9.0.
mW.

(Example 4) In Example 1, the semiconductor layer 12a on which the photosensitizing dye 13a was adsorbed was formed on the surface of the fluorine-doped tin oxide layer 15a. Thus, a photocell D was manufactured. The photoelectric conversion efficiency of this photovoltaic cell D reached 13%, and the maximum power was 9.8.
mW.

(Example 5) In Example 1, the semiconductor layer 12a having the photosensitizing dye 13a adsorbed thereon was formed on the surface of the fluorine-doped tin oxide layer 15a.
The semiconductor layer 12b adsorbed by the fluorine-doped tin oxide layer 1
A photovoltaic cell E was formed on the surface of the photovoltaic cell 5b, and otherwise configured similarly to the photovoltaic cell A of Example 1. The photoelectric conversion efficiency of this photovoltaic cell E reached 11%, and the maximum power was 8.5 mW.

Comparative Example 1 In this comparative example, a photovoltaic cell F as shown in FIG. 3 is manufactured. <Production of Various Substrates> A commercially available transparent conductive glass plate (15/20) (1 cm square) having a fluorine-doped tin oxide layer 15 formed on one surface of a transparent glass plate 16 was prepared. Also, separately
A transparent conductive material having a semiconductor layer for photosensitizing dye adsorption on a fluorine-doped tin oxide layer 11 of a commercially available transparent conductive glass plate (11/17) having a fluorine-doped tin oxide layer 11 formed on one surface of a transparent glass plate 17 Glass plate (13/12/11/1
7) (1 cm square) was prepared.

The formation of the semiconductor layer and the adsorption of the photosensitizing dye to the semiconductor layer were performed in the same manner as described in Example 1.

<Preparation of Photocell F> A transparent conductive glass plate (13/12/1) having a semiconductor layer adsorbing the above-described photosensitizing dye was prepared.
1/17), an epoxy-based thermosetting adhesive (Struck Bond manufactured by Mitsui Toatsu Chemicals, Inc.) was applied in a 1 mm wide frame shape, and Example 1 was placed in a frame surrounded by the adhesive. The same electrolyte solution 14 as that used in the above was dropped, the transparent conductive glass plate (15/16) was overlaid and bonded thereto, and this was heated and cured at 100 ° C. for 3 hours in an oven. F was produced. In addition, a lead wire was attached to each electrode layer at the time of manufacturing the photovoltaic cell.

<Measurement of Performance of Photocell F> Using this photocell F, the battery performance was measured from the front side (in the direction of the arrow) using a solar simulator (AM 1.5, 96 mW / cm ² ). Reached 7%, the maximum power was 5.3 mW, and the photoelectric conversion efficiency was inferior to each of the above examples.

[0085]

As described above, the dye-sensitized photovoltaic cell of the present invention is excellent in photoelectric conversion efficiency and increases the power supply per unit area.

Therefore, if the dye-sensitized photovoltaic cell of the present invention is installed on a limited area such as the roof of a house and used as a solar cell, it can be used as a conventional pn junction photocell using a silicon semiconductor. The production cost is lower than that, the photoelectric conversion efficiency does not decrease rapidly even under the condition of non-direct sunlight or cloudy sky, and a larger electric power can be supplied as compared with the conventional dye-sensitized photocell.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of a dye-sensitized photocell of the present invention.

FIG. 2 is a cross-sectional view showing another example of the dye-sensitized photocell of the present invention.

FIG. 3 is a cross-sectional view illustrating an example of a conventional dye-sensitized photovoltaic cell.

[Explanation of symbols]

 A, B Dye-sensitized photocells 10a, 10b, 10c, 10d Photoelectric conversion layers 11a, 11b, 11c, 11d Electrode layers 12a, 12b, 12c, 12d Semiconductor layers 13a, 13b, 13c, 13d Photosensitizing dyes 14a, 14b , 14c, 14d Electrolyte layer 15a, 15b, 15c, 15d Electrode layer 20, 20a, 20b Light-transmitting insulating substrate

Claims (5)

[Claims] 1. A photoelectric conversion layer formed by laminating an electrode layer, a semiconductor layer made of a metal oxide to which a photosensitizing dye is adsorbed, an electrolyte layer, and an electrode layer in this order at least with a light-transmitting insulating substrate interposed therebetween. A dye-sensitized photocell, wherein two layers are alternately stacked. 2. The dye-sensitized photovoltaic cell according to claim 1, wherein the electrode layer farthest away from the light incident side is a reflective electrode layer. 3. The dye-sensitized photovoltaic cell according to claim 2, wherein the reflective electrode layer is made of a corrosion-resistant conductive metal. 4. The dye-sensitized photovoltaic cell according to claim 1, wherein the photosensitizing dye comprises a ruthenium metal complex. 5. The dye-sensitized photovoltaic cell according to claim 1, wherein the metal oxide comprises titanium oxide.