JP2002305041A - Solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar cell having a superior durability. SOLUTION: A solar cell 1A has a first substrate 2, a first electrode 3 installed on the upper face of the first substrate 2, a semiconductor electrode 4 installed on the upper face of the first electrode 3, a wall part (wall member) 5 installed so as to surround the semiconductor electrode 4 and having a housing space 8 in this inside, a second electrode 6 installed opposing to the semiconductor electrode 4 via the wall part 5, a second substrate 7 installed on the upper face of the second electrode 6, and an electrolyte gel (gelatinous electrolyte) 81 housed in the housing space 8. The electrolyte gel 81 retains an electrolytic solution in a gel substrate, and as the gel substrate, a material which is mainly constituted of a thermoplastic resin, mainly constituted of a thermosetting resin, mainly constituted of a copolymer obtained by a polymerization of at least two kinds of compounds, or mainly constituted of the compound having a siloxane bond is preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a solar cell.

[0002]

2. Description of the Related Art Conventionally, as an environmentally friendly power source,
Solar cells using silicon are attracting attention. Among the solar cells using silicon, there are single-crystal silicon solar cells used for artificial satellites and the like, but practically, solar cells using polycrystalline silicon and amorphous silicon are particularly used. Solar cells have been put into practical use for industrial and home use.

However, these solar cells using silicon all use a vacuum process such as a CVD (Chemical Vapor Deposition) method, so that the manufacturing cost is high, and
In these processes, a large amount of heat and electricity are used, so that the balance between the energy required for manufacturing and the energy generated by the solar cell is extremely poor, and it is not necessarily an energy-saving power source.

On the other hand, a so-called "wet solar cell",
A new type of non-silicon solar cell called a "fourth generation photocell" has been proposed.

In this solar cell, an electrolyte solution is filled between an electrode made of titanium dioxide and a counter electrode, and the periphery of the solar cell is sealed with a sealing member so that the electrolyte solution does not leak. ing.

However, in this solar cell, since the electrolyte solution is used, for example, deterioration or deterioration of the sealing member over time due to light irradiation, or deformation due to thermal expansion or contraction of the solar cell, etc. In some cases, leakage of the electrolyte solution from the sealing portion by the sealing member may occur. That is, such a solar cell has a problem in durability.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a solar cell having excellent durability.

[0008]

This and other objects are achieved by the present invention which is defined below as (1) to (24).

(1) A semiconductor electrode mainly composed of titanium oxide and an electrolyte are interposed between an anode and a cathode such that the semiconductor electrode is located on the cathode side and the electrolyte is located on the anode side. A solar cell, wherein a gel electrolyte is used as the electrolyte.

(2) The solar cell according to (1), wherein the gel electrolyte holds an electrolyte solution in a gel base material.

(3) The solar cell according to the above (2), wherein the gel base is mainly composed of a thermoplastic resin.

(4) The solar cell according to (2), wherein the gel base material is mainly composed of a thermosetting resin.

(5) The solar cell according to the above (2), wherein the gel base material is mainly composed of a copolymer obtained by polymerizing at least two kinds of compounds.

(6) The solar cell according to (5), wherein the copolymer is obtained mainly by ionic polymerization.

(7) The solar cell according to the above (2), wherein the gel base material is mainly composed of a compound having a siloxane bond.

(8) The gel electrolyte comprises a constituent material of the gel base and the electrolyte solution in a weight ratio of 1: 1.
The solar cell according to any one of the above (2) to (7), which contains the solar cell at a ratio of １ ： 1: 50.

(9) The solar cell according to any one of (1) to (8), further including a wall member that covers the periphery of the semiconductor electrode and the electrolyte.

(10) A semiconductor electrode mainly composed of titanium oxide and an electrolyte are interposed between the anode and the cathode such that the semiconductor electrode is located on the cathode side and the electrolyte is located on the anode side. A solar cell in which the periphery of the semiconductor electrode and the electrolyte is covered with a wall member, wherein the wall member is made of a material having resistance to ultraviolet rays.

(11) The solar cell according to (10), wherein the material is a silicone resin or a glass material.

(12) A substrate for supporting at least one of the anode and the cathode, wherein the wall member is formed integrally with the substrate.
The solar cell according to 1).

(13) A semiconductor electrode mainly composed of titanium oxide and an electrolyte are interposed between the anode and the cathode such that the semiconductor electrode is located on the cathode side and the electrolyte is located on the anode side. A solar cell covered with a wall member around the semiconductor electrode and the electrolyte, comprising a substrate supporting at least one of the anode and the cathode,
The solar cell, wherein the wall member is formed integrally with the substrate.

(14) The above-mentioned (13), wherein the wall member and the substrate are made of a material resistant to ultraviolet rays.
The solar cell according to 1.

(15) The solar cell according to (14), wherein the material is a silicone resin or a glass material.

(16) The solar cell according to any one of the above (1) to (15), wherein the titanium oxide is mainly composed of titanium dioxide.

(17) The solar cell according to any one of the above (1) to (16), wherein the semiconductor electrode is manufactured using a titanium oxide powder having an average particle size of 1 nm to 1 μm.

(18) The solar cell according to any one of (1) to (17), wherein the semiconductor electrode is porous.

(19) The semiconductor electrode has a porosity of 5
The solar cell according to the above (18), which has a content of about 90%.

(20) The semiconductor electrode has a surface roughness R
(18) or (1), wherein a is 5 nm to 10 μm.
The solar cell according to 9).

(21) The solar cell according to any one of the above (1) to (20), wherein the semiconductor electrode has a film shape.

(22) The solar cell according to (21), wherein the semiconductor electrode has an average thickness of 0.1 to 300 μm.

(23) The solar cell according to any one of the above (1) to (22), wherein the semiconductor electrode has been subjected to a visualization treatment for allowing light having a wavelength in a visible light region to be absorbed.

(24) The photoelectric conversion efficiency when the incident angle of light on the semiconductor electrode is 90 ° is R ₉₀ and the incident angle of light is 5
The solar cell according to any one of (1) to (23), wherein R ₅₂ / R ₉₀ is 0.8 or more, where R ₅₂ is the photoelectric conversion efficiency at 2 °.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the solar cell of the present invention shown in the attached drawings will be described below in detail.

<First Embodiment> FIG. 1 is a cross-sectional view showing a first embodiment of a solar cell (photovoltaic cell: photoelectric conversion element) of the present invention, and FIG. 2 is a cross-sectional view near a light receiving surface of a semiconductor electrode. .

The solar cell 1A shown in FIG.
And a first electrode 3 provided on the upper surface of the first substrate 2;
A semiconductor electrode 4 provided on the upper surface of the first electrode 3; a wall (wall member) 5 provided so as to surround the semiconductor electrode 4 and having a storage space 8 therein; A second electrode 6 disposed opposite to the second electrode 4; a second substrate 7 disposed on the upper surface of the second electrode 6;
It has an electrolyte gel (gel electrolyte) 81 housed therein.

Hereinafter, each component will be described. First
The substrate 2 is a support member for the first electrode 3 and is formed of a plate-shaped member.

As shown in FIG. 1, the solar cell 1A according to the present embodiment is used by irradiating (irradiating) light from the first substrate 2 and a first electrode 3 to be described later. . Therefore, each of the first substrate 2 and the first electrode 3 is preferably substantially transparent (colorless transparent, colored transparent or translucent). Thereby, light can efficiently reach the light receiving surface of the semiconductor electrode 4.

The first substrate 2 and a second substrate 7 to be described later are made of, for example, various glass materials, various ceramic materials, various plastic materials, resin materials such as polycarbonate (PC), or aluminum. One or more of such metal materials can be used in combination.

The thickness (average) of each of the first substrate 2 and the second substrate 7 is appropriately set depending on the material, use, and the like, and is not particularly limited. For example, the following can be used.

When the first substrate 2 and the second substrate 7 are made of a hard material such as a glass material, the thickness thereof is preferably about 0.1 to 1.5 mm. More preferably, it is about 0.8 to 1.2 mm.

When the first substrate 2 and the second substrate 7 are made of a flexible material (flexible material) such as polyethylene terephthalate (PET), the thickness of each of them is 0.5 to 0.5. The thickness is preferably about 150 μm, and more preferably about 10 to 75 μm. The first substrate 2 can be omitted if necessary.

On the upper surface of the first substrate 2, a layered (flat) plate
The first electrode 3 is provided. This first electrode 3
Captures electrons generated at the semiconductor electrode 4 described later and transmits the captured electrons to the external circuit 9. That is, the first electrode 3 forms a cathode.

The first electrode 3 is made of, for example, indium tin oxide (ITO), fluorine-doped tin oxide (FTO), or indium oxide (I
O), metal oxides such as tin oxide (SnO ₂ ), metals such as aluminum, nickel, chromium, platinum, silver, gold, copper, molybdenum, titanium, tantalum or alloys containing these, or carbon. One type or a combination of two or more types can be used.

The thickness (average) of the first electrode 3 is appropriately set depending on the material, application, etc., and is not particularly limited.
For example, the following can be performed.

When the first electrode 3 is made of the above-mentioned metal oxide (transparent conductive metal oxide), its thickness is as follows.
It is preferably about 0.05 to 5 μm,
More preferably, it is about 1.5 μm.

When the first electrode 3 is made of the above-mentioned metal, an alloy containing them, or carbon, the thickness thereof is preferably about 0.01 to 1 μm, and is preferably about 0.03 to 1 μm. More preferably, it is about 0.1 μm.

On the upper surface of the first electrode 3, there is provided a semiconductor electrode 4 mainly composed of titanium oxide, preferably in a film (layer) form.

When the semiconductor electrode 4 is irradiated with light such as sunlight (hereinafter, simply referred to as “light”), electrons are excited to generate electrons and holes.

The semiconductor electrode 4 is formed as shown in FIG.
It is preferably porous having a plurality of holes 41. The semiconductor electrode 4 will be described later in detail.

A wall 5 is provided upright on the upper surface of the first electrode 3 so as to surround the semiconductor electrode 4. A storage space 8 is defined inside the wall portion 5 by the semiconductor electrode 4 and a second electrode 6 described later, and an electrolyte gel 81 described later is stored therein.

The wall 5 has a function as a sealing member for hermetically sealing the side surface of the solar cell 1A.
It also functions as a spacer for keeping the distance between the electrode 3 and the second electrode 6 constant.

The width (average) of the wall 5, that is, the length in the horizontal direction in FIG. 1, is not particularly limited.
It is preferably about 10 to 10 mm, and more preferably about 0.5 to 5 mm.

The height (average) of the wall 5, that is, the length (thickness) in the vertical direction in FIG. 1 is not particularly limited, but is preferably, for example, about 0.001 to 1.0 mm.
More preferably, it is about 0.01 to 0.1 mm.

The wall 5 is made of an insulating material. As the insulating material, for example, various resin materials such as polycarbonate, ultraviolet curing resin, thermosetting resin, epoxy resin, polyimide resin, various glass materials,
One or a combination of two or more of various free-cutting ceramic materials can be used. In particular, the wall 5
In the case where the material has a function as a spacer, it is preferable to use polycarbonate and various glass materials among the above-mentioned materials in terms of higher strength.

The second electrode 6 is provided on the upper surface of the wall 5 so as to face the semiconductor electrode 4. This second electrode 6
Supplies electrons supplied via the external circuit 9 to an electrolyte gel 81 described later. That is, the second electrode 6
Construct the anode.

As the constituent material of the second electrode 6, the same material as that described for the first electrode 3 can be used.

The thickness (average) of the second electrode 6 is appropriately set depending on the material, use, and the like, and is not particularly limited.

On the upper surface of the second electrode 6, a plate-shaped second substrate 7 is provided. This second substrate 7 is a support member for the second electrode 6. Note that the second substrate 7
It can be omitted as necessary.

In the storage space 8, an electrolyte gel (gel electrolyte) 81 is stored as an electrolyte.

Incidentally, an electrolyte solution (a liquid electrolyte)
In solar cells using, the advantage that the electrolyte solution and the semiconductor electrode can be surely brought into contact with each other, and particularly when the semiconductor electrode is porous, the electrolyte solution penetrates into the inside thereof and the contact area with the semiconductor electrode Can be increased, and as a result, good power generation efficiency can be obtained.

Further, a solar cell using a solid electrolyte (solid electrolyte) has an advantage that the disadvantage of liquid leakage can be reliably prevented, and as a result, good durability is exhibited. .

The solar cell 1A of the present invention using the electrolyte gel 81 has both the advantages of the solar cell using the above-described electrolyte solution and the advantages of the solar cell using the solid electrolyte, that is, the electrolyte gel 81. And the semiconductor electrode 4 can be reliably contacted, and the inconvenience of liquid leakage can be reliably prevented. As a result, in the solar cell 1A, excellent power generation efficiency is obtained, and excellent durability is exhibited.

The electrolyte gel 81 also has an advantage that the concentration (content) of the electrolyte component, which is an advantage of the electrolyte solution, can be easily selected.

Further, since the electrolyte gel 81 also has a shape retaining property which is an advantage of the solid electrolyte, the
In A, it is not necessary to strictly perform the sealing (sealing) by the above-described wall portion 5, or the wall portion 5 may be omitted depending on the strength of the electrolyte gel 81 or the like.

The capacity (volume) of this electrolyte gel 81
Is not particularly limited, and can be appropriately set depending on, for example, the dimensions of the solar cell 1A to be manufactured, the concentration of the electrolyte component in the electrolyte solution, and the like. Such an electrolyte gel 81
Holds an electrolyte solution in a gel base material.

The electrolyte solution is not particularly limited. For example, I / I ₃ system, Br / Br ₃ system, Cl / Cl ₃
Systems, F / F ₃ based halogen-based, such as, quinone / hydroquinone system redox electrolyte of: a combination of one or more of (a redox substance electrolyte component), for example, various water, acetonitrile, ethylene carbonate ,
A solution dissolved in a solvent such as propylene carbonate or polyethylene glycol (or a mixed solvent thereof) can be used.

Among these, an iodine solution (I / I ₃ system solution) is particularly preferably used as the electrolyte solution. More specifically, the electrolyte solution is, for example, a solution of iodine and potassium iodide dissolved in ethylene glycol, dimethylhexylimidazolium, iodine and lithium iodide were dissolved in acetonitrile to which a predetermined amount of Tertiary-butylpyridine was added. Solution, Iodolyt
e TG50 (manufactured by Solaronics), 1,2-dimethyl-
For example, 3-propylimidazolium iodide can be used.

The concentration (content) of the electrolyte component in the electrolyte solution is not particularly limited.
It is preferably about 25 wt%, and 0.5 to 15 wt%.
% Is more preferable.

Examples of the gel base material include those mainly composed of a thermoplastic resin, those mainly composed of a thermosetting resin, those mainly composed of a copolymer, and those mainly composed of a siloxane bond. Can be used, and any two or more of these can be used in combination.

Examples of the thermoplastic resin include polyethylene oxide (PEO) and polyacrylonitrile (PA).
N), polyvinylidene fluoride (PVDF), polymethyl methacrylate (PMMA) and the like.
Species or a combination of two or more can be used.

Examples of the thermosetting resin include polyimide resin (PI), epoxy resin, phenolic resin, and urea resin.

The copolymer is obtained by polymerizing at least two kinds of compounds (precursors of the copolymer), for example, by ionic polymerization (cationic polymerization, anionic polymerization), radical polymerization or the like, or by using these in combination. For example, epoxy-based copolymers, vinyl ether-based copolymers, oxedane-based copolymers, urethane acrylate-based copolymers, epoxy acrylate-based copolymers, ester acrylate-based copolymers, acrylate-based copolymers Polymers.

Accordingly, as the compound (precursor of the copolymer), for example, any two or more selected from urethane, polyacene, polyacetylene, polyethylene, polycarbonate, polypyrrole, polyaniline, active sulfur and the like are appropriately selected. Can be used.

Examples of the compound having a siloxane bond include polysiloxane, polydimethylsiloxane, polyalkylphenylsiloxane, and polymetallosiloxane in which a part of a silicon atom is substituted with another metal atom (eg, aluminum, titanium, etc.). Is mentioned.

The electrolyte gel 81 preferably contains the constituent material of the gel base material and the electrolyte solution in a weight ratio of about 1: 1 to 1:50, and in a weight ratio of 1: 3 to 1:10. More preferably, it is contained. By setting the composition of the electrolyte gel 81 within the above range, the electrolyte gel 81 can secure a suitable mechanical strength while maintaining a suitable conductivity.

In such a solar cell 1A, when light enters the semiconductor electrode 4, electrons are excited in the semiconductor electrode 4 to generate electrons and holes.

Then, the electrons gather through the first electrode 3 and the external circuit 9 to the counter electrode second electrode 6. These electrons reduce the electrolyte component in the electrolyte gel 81 to form a reduced form.

When this reduced form diffuses in the electrolyte gel 81 and reaches the surface (light receiving surface) of the semiconductor electrode 4, electrons are removed by holes remaining on the surface of the semiconductor electrode 4 (oxidation). And oxidized form. This completes the current loop.

The oxidant diffuses and moves in the electrolyte gel 81, returns to the second electrode 6, and repeats the action of receiving electrons and being reduced.

Note that electrons and holes are simultaneously generated in the semiconductor electrode 4 by light irradiation, but in the following description, "electrons are generated" for convenience.

The semiconductor electrode 4 is mainly composed of titanium oxide. Examples of the titanium oxide include titanium dioxide, titanium monoxide, dititanium trioxide, and the like.
Species or a combination of two or more species can be used, and among them, titanium oxide preferably is mainly composed of titanium dioxide. Titanium dioxide is
Since the sensitivity to light is high, in the semiconductor electrode 4 mainly using titanium dioxide as titanium oxide, the light use efficiency is further improved.

Further, as the titanium dioxide, those having a crystal structure mainly of titanium dioxide of anatase type, those mainly containing rutile type titanium dioxide, and a mixture of titanium dioxide of anatase type and rutile type titanium dioxide can be used. Any of the main ones may be used.

Since rutile-type titanium dioxide can use light having a wavelength in the visible light region near the ultraviolet region, the semiconductor electrode 4 mainly composed of rutile-type titanium dioxide emits light. It has the advantage of excellent utilization efficiency.

Further, since the crystal structure of rutile-type titanium dioxide is stable, the semiconductor electrode 4 mainly composed of rutile-type titanium dioxide undergoes aging (even if exposed to a severe environment). (Deterioration) is small and stable performance can be obtained continuously for a long period of time.

On the other hand, since the crystal structure of anatase type titanium dioxide is relatively unstable, the semiconductor electrode 4 mainly composed of anatase type titanium dioxide has an advantage that electrons are easily generated. .

Further, the semiconductor electrode 4 mainly composed of a mixture of rutile-type titanium dioxide and anatase-type titanium dioxide can have the advantages described above.

When mixed in this way, the rutile-type titanium dioxide and the anatase-type titanium dioxide are not particularly limited. For example, the weight ratio is 95: 5 to 5: 9.
It is preferably about 5 and more preferably about 80:20 to 20:80.

The semiconductor electrode 4 may be dense, but is preferably porous as described above. FIG. 2 schematically shows a state in which light is incident near the light receiving surface of the semiconductor electrode 4. As shown in FIG. 2, the porous semiconductor electrode 4 emits light (arrows in FIG. 2).
Penetrates from the surface (light receiving surface) of the semiconductor electrode 4 further into the inside, and transmits through the semiconductor electrode 4 or is reflected in the hole 41. For this reason, light is more frequently emitted to the semiconductor electrode 4.
Electrons are generated in the inside, and the light use efficiency is improved.

Further, in the porous semiconductor electrode 4, the electrolyte gel 81 can be penetrated into the inside, so that a sufficient contact area with the electrolyte gel 81 can be ensured.

From the above, the solar cell 1A using the porous semiconductor electrode 4 can generate power more efficiently.

In this case, the surface area of the semiconductor electrode 4 is significantly increased (for example, 50 to 10,000 times) as compared with the surface area of the dense semiconductor electrode. This allows
In the solar cell 1A using such a semiconductor electrode 4, a large current (for example, 50 to 10,000 times) is generated as compared with a solar cell using a dense semiconductor electrode.

The index indicating the degree of such porosity includes, for example, the porosity (porosity) of the semiconductor electrode 4, the surface roughness Ra of the light receiving surface of the semiconductor electrode 4, and the like. It is preferable that one of the porosity and the surface roughness Ra of the light receiving surface satisfies the following condition, and that both the porosity and the surface roughness Ra of the light receiving surface satisfy the following condition. preferable.

Although the porosity of the semiconductor electrode 4 is not particularly limited, it is, for example, preferably about 5 to 90%, more preferably about 15 to 50%, and more preferably about 20 to 50%.
More preferably, it is about 40%.

Further, the surface roughness R of the light receiving surface of the semiconductor electrode 4
Although a is not particularly limited, for example, 5 nm to 1
It is preferably about 0 μm, and more preferably about 20 nm to 1 μm.

In the semiconductor electrode 4 having the degree of porosity within the above-described range, the light irradiation area and the electrolyte gel 8
1 can be further increased. Therefore, the solar cell 1A using such a semiconductor electrode 4 can generate power more efficiently.

From such a viewpoint, the semiconductor electrode 4 is
It is preferably manufactured using titanium oxide powder (powder-like titanium oxide). Thereby, the semiconductor electrode 4 can be easily and reliably made porous.

The average particle size of the titanium oxide powder is not particularly limited, but is preferably, for example, about 1 nm to 1 μm, and more preferably about 5 to 50 nm. By setting the average particle size of the titanium oxide powder within the above range, the uniformity of the titanium oxide powder in the semiconductor electrode material is improved. In addition, by reducing the average particle size of the titanium oxide powder, the specific surface area of the obtained semiconductor electrode 4 can be further increased.

The semiconductor electrode 4 may have a relatively large thickness, but may have a film-like (layer-like) shape as described above.
Are preferred. By using the film-shaped semiconductor electrode 4 for the solar cell 1A, the power generation efficiency (photoelectric conversion efficiency) of the solar cell 1A is further improved, and the solar cell 1A is made thinner (smaller) and the manufacturing cost is reduced. Is advantageous.

In this case, the average thickness (film thickness) of the semiconductor electrode 4 is not particularly limited.
It is preferably about 300 μm, and 0.5 to 100 μm.
m, more preferably about 1 to 25 μm. When the average thickness of the semiconductor electrode 4 is less than the lower limit described above, depending on the porosity and the like, the light incident on the semiconductor electrode 4 is significantly transmitted, and the light use efficiency may be reduced. On the other hand, even if the thickness of the semiconductor electrode 4 is increased beyond the above-mentioned upper limit value, further increase in light use efficiency cannot be expected.

Further, such a semiconductor electrode 4 is subjected to a visualization process, so that the semiconductor electrode 4 is in a visible light region (usually 400 to 750).
It is preferable that light of a wide range of wavelengths (about nm) can be absorbed. Thereby, the semiconductor electrode 4 can further improve the light use efficiency and generate electrons more reliably.

Examples of such a visualization method include a dye adsorption method for adsorbing a dye, an oxygen defect formation method for forming oxygen defects, and an atomic substitution method for substituting a part of titanium atoms with metal atoms different from titanium atoms. And the like, and one or more of these can be used in combination. Hereinafter, each of these methods will be described in detail.

Dye Adsorption Method In the dye adsorption method, a film-shaped body (hereinafter, simply referred to as a “film-shaped body”) in which a semiconductor electrode material is formed into a film, and a solvent in which a dye is dissolved or suspended (dispersed), for example, And, for example, immersion,
By contacting by coating or the like, the dye is adsorbed on the surface of the film and / or in the pores.

The dye is not particularly limited.
For example, pigments, dyes and the like can be mentioned, and these can be used alone or as a mixture. However, pigments are preferable in that they are less deteriorated and deteriorated with time, and dyes are more excellent in adsorptivity.

The pigment is not particularly limited.
For example, phthalocyanine green, phthalocyanine pigments such as phthalocyanine blue, fast yellow, disazo yellow, condensed azo yellow, penzoimidazolone yellow, dinitroaniline orange, penzimidazolone orange, toluidine red, permanent carmine, permanent red, naphthol red, Condensed azo red, azo pigments such as benzimidazolone carmine, benzimidazolone brown, anthrapyrimidine yellow, anthraquinone pigments such as anthraquinonyl red, azomethine pigments such as copper azomethine yellow, quinophthalone pigments such as quinophthalone yellow, iso Isoindoline pigments such as indoline yellow, nitroso pigments such as nickel dioxime yellow, and perinone face such as perinone orange Quinacridone magenta, quinacridone maroon, quinacridone scarlet, quinacridone pigments such as quinacridone red, perylene red, perylene pigments such as perylene maroon, pyrropyrrole pigments such as diketopyrrolopyrrole red, and dioxazine pigments such as dioxazine violet. Organic pigments, such as
Carbon pigments such as carbon black, lamp black, furnace black, ivory black, graphite, fullerene, chromate pigments such as graphite, molybdate orange, cadmium yellow, cadmium lithopone yellow, cadmium orange, cadmium lithopone orange, Sulfide pigments such as silver vermilion, cadmium red, cadmium lithopone red, ocher, titanium yellow, titanium barium nickel yellow, red iron oxide, lead red, amber, brown iron oxide, zinc iron chrome brown, chromium oxide,
Cobalt green, cobalt chrome green, titanium cobalt green, cobalt blue, cerulean blue,
Oxide pigments such as cobalt aluminum chrome blue, iron black, manganese ferrite black, cobalt ferrite black, copper chromium black, copper chromium manganese black, hydroxide pigments such as viridian, ferrocyanide pigments such as navy blue, ultramarine Or a combination of two or more of silicate pigments such as silicate pigments, phosphate pigments such as cobalt violet and mineral violet, and inorganic pigments such as cadmium sulfide and cadmium selenide. Can be.

The dye is not particularly limited. For example, RuL ₂ (SCN) ₂ , RuL ₂ Cl ₂ , RuL ₂ (CN) ₂ ,
um535-bisTBA (manufactured by Solaronics), metal complex dyes such as [RuL ₂ (NCS) ₂ ] ₂ H ₂ O, cyan dyes, xanthene dyes, azo dyes, hibiscus dyes, blackberry dyes, raspberry dyes, One or more of pomegranate juice pigment, chlorophyll pigment and the like can be used in combination. L in the above composition formula is 2,2′-bipyridin
e or a derivative thereof.

Oxygen Deficiency Forming Method The oxygen deficiency forming method is not particularly limited. For example, a method in which a titanium oxide powder or a film is heat-treated in a hydrogen atmosphere (reducing atmosphere), vacuum (for example, 10 ⁻⁵ to 10 ⁻⁵ )
A method of performing a heat treatment under 10 ⁻⁶ Torr), a method of performing a low-temperature plasma treatment, and the like are given. Among them, as the oxygen defect forming method, a method of heat-treating a titanium oxide powder or a film in a hydrogen atmosphere is preferable.

Atom replacement method As the atom replacement method, for example, a method of firing (sintering) a film of a semiconductor electrode material to which an inorganic sensitizer composed of the above-described metal atom or its oxide is added, A method of injecting (implanting) the ionized metal atom into the body may be used. Among these, a method of firing a film of a semiconductor electrode material to which an inorganic sensitizer is added is more preferable as the atom replacement method. In addition, such an atom substitution method can be applied to titanium oxide powder.

In such a solar cell 1A using the semiconductor electrode 4, the photoelectric conversion efficiency when the incident angle of light on the semiconductor electrode 4 is 90 ° is R _90, and the photoelectric conversion efficiency when the incident angle of light is 52 ° is when was the R ₅₂ efficiency is preferably R ₅₂ / R ₉₀ has a characteristic such that the degree of 0.8 or more, 0.85
More preferably, it is at least about the above. Satisfying such a condition means that the semiconductor electrode 4 has low directivity to light, that is, has isotropic properties. Therefore, solar cell 1 having such a semiconductor electrode 4
A can generate power more efficiently over almost the entire sunshine duration.

Such a solar cell 1A can be manufactured, for example, as follows. First, a first substrate 2 and a second substrate 7 each made of, for example, quartz glass are prepared. As the first substrate 2 and the second substrate 7, those having a uniform thickness and no bending are preferably used.

<1> First, the first electrode 3 is formed on the upper surface of the first substrate 2, and the second electrode 6 is formed on the upper surface of the second substrate 7, respectively.

The first electrode 3 can be formed by using a material for the first electrode 3 made of, for example, ITO or the like by using, for example, an evaporation method, a sputtering method, a printing method, or the like.

The second electrode 6 can be formed by using the material of the second electrode 6 made of, for example, platinum or the like, for example, by using a vapor deposition method, a sputtering method, a printing method, or the like.

<2> Next, the semiconductor electrode 4 is formed on the upper surface of the first electrode 3. The semiconductor electrode 4 is formed in a film shape (thick film and thin film) by a method such as dipping, doctor blade, spin coating, brush coating, spray coating, various coating methods such as a roll coater, and a thermal spraying method. can do. Among them, the method of forming the semiconductor electrode 4 is preferably a method using various coating methods.

According to such a coating method, the operation is as follows:
Since it is extremely simple and does not require a large-scale device, it is advantageous for reducing the manufacturing cost and the manufacturing time of the semiconductor electrode 4 and the solar cell 1A. Further, according to the coating method, for example, by using masking or the like, the semiconductor electrode 4 having a desired pattern shape can be easily obtained.

An example of a forming method of the semiconductor electrode 4 by a coating method will be described below. In the following description,
Visualization treatment method (<2A> dye adsorption method, <2B>, <2A>
2C> Oxygen deficiency forming method and <2D> Atom replacement method), and the same matters will not be described later. Further, regarding the oxygen defect forming method, <2B> a case where the method is applied to the titanium oxide powder,
The description will be made separately for the case where C> is applied to a film.

<2A>: Dye adsorption method [Preparation of titanium oxide powder] <A0> A predetermined mixing ratio of rutile-type titanium dioxide powder and anatase-type titanium dioxide powder (only anatase-type titanium dioxide powder, rutile-type titanium dioxide powder) (Including the case of using only titanium dioxide powder).

The average particle size of the rutile-type titanium dioxide powder and the average particle size of the anatase-type titanium dioxide powder may be different from each other or may be the same. Is preferred. The average particle size of the entire titanium oxide powder is in the above-mentioned range.

[Preparation of Coating Solution (Semiconductor Electrode Material)] <A1> First, the titanium oxide powder prepared in the above step was mixed with an appropriate amount of water (for example, distilled water, ultrapure water, ion-exchanged water,
RO water, etc.).

<A2> Next, a stabilizer such as nitric acid is added to the suspension, and the suspension is sufficiently kneaded in a mortar made of agate (or made of alumina).

<A3> Next, the above-mentioned water is added to the suspension, followed by further kneading. At this time, the mixing ratio of the stabilizer to water is preferably 10:90 to 4 by volume ratio.
About 0:60, more preferably 15:85 to 30:70
And the viscosity of the suspension is, for example, 0.2-30.
Approximately cP.

<A4> Thereafter, a surfactant is added to the suspension so as to have a final concentration of, for example, about 0.01 to 5 wt%, and the suspension is kneaded. Thus, a coating liquid (semiconductor electrode material) is prepared.

The surfactant may be cationic,
Any of anionic, amphoteric, and nonionic may be used, but a nonionic one is preferably used.

Further, as the stabilizer, nitric acid is used instead of nitric acid.
A titanium oxide surface modification reagent such as acetic acid or acetylacetone can also be used.

The coating liquid (semiconductor electrode material) contains
If necessary, various additives such as a binder such as polyethylene glycol, a plasticizer, and an antioxidant may be added.

[Formation of Semiconductor Electrode 4] <A5> A coating solution is applied and dried on the upper surface of the first electrode 3 by a coating method (for example, dipping or the like) to form a film (coating). . Alternatively, the coating and drying operations may be performed a plurality of times to laminate.

Next, if necessary, the film may be subjected to a heat treatment (for example, firing) at a temperature of about 250 to 500 ° C. for about 0.5 to 3 hours. As a result, the titanium oxide powder that has just stopped contacting is diffused at the contact portion, and the titanium oxide powders are fixed (fixed) to some extent. In this state, the film becomes porous.

<A6> The film obtained in the above step <A5> may be subjected to post-treatment, if necessary.

As the post-processing, for example, machining (post-processing) such as grinding and polishing for adjusting the shape.
And other post-treatments such as cleaning and chemical treatment.

The surface roughness Ra of the light receiving surface may be adjusted by post-processing in the present step <A6>.

<A7> Next, a solution in which a dye such as carbon black is dissolved or suspended (dispersed) is added to the first solution.
The substrate 2, the first electrode 3, and the layered body of the film are dipped or the like. As a result, the solution penetrates into the pores of the film and reaches the first electrode 3 side, and the dye is adsorbed on the surface and the pores of the film.

The solvent for dissolving or suspending (dispersing) the dye is not particularly limited. For example, various types of water, methanol, ethanol, isopropyl alcohol, acetonitrile, ethyl acetate, ether, methylene chloride, NMP
One or two or more of (N-methyl-2-pyrrolidone) and the like can be used in combination.

Thereafter, the laminate is taken out of the solution, and the solvent is removed by, for example, a method of natural drying or a method of blowing a gas such as air or nitrogen gas.

Further, if necessary, the laminate may be dried in a clean oven or the like at a temperature of, for example, about 60 to 100 ° C. for about 0.5 to 2 hours. This allows the dye to be more firmly adsorbed to the film.

<2B>: Oxygen vacancy forming method (when applied to titanium oxide powder) [Preparation of titanium oxide powder] <B0> A predetermined mixing ratio (rutile) of rutile type titanium dioxide powder and anatase type titanium dioxide powder (Including the case of only the titanium dioxide powder of the type)). In addition, by the heat treatment by the oxygen defect formation method described later,
When it is assumed that the crystal structure of titanium dioxide changes (changes) from anatase type to rutile type, only anatase type titanium dioxide powder may be used.

Next, to the compounded titanium oxide powder,
Heat treatment by an oxygen defect forming method is performed. The heat treatment at this time is performed in a hydrogen atmosphere, preferably at a temperature of 800.
The temperature is about 1200 to 1200 ° C. and about 0.2 to 3 hours, more preferably about 900 to 1200 ° C. and about 0.5 to 1 hour.

At this time, if the titanium oxide powder contains anatase-type titanium dioxide powder, the crystal structure of anatase-type titanium dioxide is partially or entirely rutile depending on the heat treatment temperature and heat treatment time. May transfer to the mold.

In the oxygen defect forming method, this step <B0>
Before this, a titanium oxide powder may be prepared by applying to rutile-type titanium dioxide powder and / or anatase-type titanium dioxide powder and blending the titanium dioxide powder.

[Preparation of Coating Solution (Semiconductor Electrode Material)] <B1> to <B4> Steps similar to the above steps <A1> to <A4> are performed.

[Formation of Semiconductor Electrode 4] <B5> The same step as the step <A5> is performed.

<B6> If necessary, the step <A6
>. The step <A7> for dye adsorption is omitted.

<2C>: Oxygen vacancy forming method (when applied to a film) [Preparation of Titanium Oxide Powder] <C0> A predetermined mixing ratio (rutile) of rutile type titanium dioxide powder and anatase type titanium dioxide powder (Including the case of only the titanium dioxide powder of the type)). In addition, by the heat treatment by the oxygen defect formation method described later,
When it is assumed that the crystal structure of titanium dioxide changes (changes) from anatase type to rutile type, only anatase type titanium dioxide powder may be used.

[Preparation of Coating Solution (Semiconductor Electrode Material)] <C1> to <C4> Steps similar to the above steps <A1> to <A4> are performed.

[Formation of Semiconductor Electrode 4] <C5> After performing the same step as the step <A5>,
The film-shaped body is subjected to a heat treatment by an oxygen defect forming method to obtain a semiconductor electrode 4. The heat treatment is performed in a hydrogen atmosphere, preferably at a temperature of about
About 3 hours, more preferably 900 to 1200 ° C
About 0.5 to 1 hour.

In this case, the heat treatment (for example, baking) in the step <A5> can be also used as the heat treatment by the oxygen defect forming method.

<C6> If necessary, the step <A6
>. The step <A7> for dye adsorption is omitted.

<2D>: Atomic substitution method [Preparation of titanium oxide powder] <D0> A predetermined mixing ratio of rutile-type titanium dioxide powder and anatase-type titanium dioxide powder (even when only rutile-type titanium dioxide powder is used) ) And mix. When it is assumed that the crystal structure of titanium dioxide changes (changes) from an anatase type to a rutile type by baking by an atom replacement method described later, only anatase type titanium dioxide powder may be used. .

[Preparation of Coating Solution (Semiconductor Electrode Material)] <D1> to <D3> Steps similar to the above steps <A1> to <A3> are performed.

<D4> In the same step as step <A4>, an inorganic sensitizer is added to the suspension and kneaded. Thus, a coating liquid (semiconductor electrode material) is prepared.

The inorganic sensitizer is not particularly restricted but includes, for example, chromium, vanadium, nickel, iron, manganese, copper, zinc, niobium and oxides thereof. Alternatively, two or more kinds can be used in combination.

The content of the inorganic sensitizer is not particularly limited, but is preferably, for example, about 0.1 to 2.5 μmol per 1 g of the titanium oxide powder.
More preferably, it is about 0.5 to 2.0 μmol.

When the titanium oxide powder contains anatase-type titanium dioxide powder and it is desired to prevent the crystal structure of the anatase-type titanium dioxide from shifting to the rutile type, a sintering aid is added. I do.

The sintering aid is preferably a metal oxide having a melting point of 900 ° C. or less. The metal oxide is not particularly limited, for example, molybdenum trioxide,
Bismuth trioxide, lead oxide, palladium oxide, diantimony trioxide, tellurium dioxide, dithallium trioxide and the like can be mentioned, and one or more of these can be used in combination.

In this case, the mixing ratio of the sintering aid and the titanium oxide powder is not particularly limited, but is preferably, for example, about 1:99 to 40:60 by volume, preferably 5:40.
The ratio is more preferably about 95 to 20:80.

Thus, the film can be fired (sintered) at a temperature of 900 ° C. or less, so that the transition of the crystal structure of titanium dioxide from an anatase type to a rutile type can be more reliably prevented (suppressed). Can be.

[Formation of Semiconductor Electrode 4] <D5> After performing the same step as the step <A5>,
For example, air, nitrogen gas, or various inert
Gas, vacuum, reduced pressure (for example, 10^-1-10 ^-6Tor
It is fired (sintered) in a non-oxidizing atmosphere as in r). This
The firing conditions at the time are, for example, as follows:
Can be.

When the titanium oxide powder does not contain anatase-type titanium dioxide powder, or when it is assumed that the crystal structure of titanium dioxide changes from anatase-type to rutile-type, the temperature is preferably 1000 to 12
The heating is performed at about 00 ° C. for about 0.5 to 10 hours.

When it is not assumed that the crystal structure of titanium dioxide changes from an anatase type to a rutile type (it is desired to prevent it), it is preferable that the temperature be about 900 ° C. or lower and 1 to 1
It is about 26 hours.

In this case, the heat treatment (for example, sintering or the like) in the step <A5> can also be performed by the sintering by the atomic substitution method.

In addition, such an atomic substitution method may be applied to rutile-type titanium dioxide powder and / or anatase-type titanium dioxide powder before the preparation of the titanium oxide powder. The titanium oxide powder may be applied later. In these cases, the firing by the atom replacement method in the present step <D5>
Can be omitted.

<D6> If necessary, the step <A6
>. The step <A7> for dye adsorption is omitted. The semiconductor electrode 4 is obtained through the steps described above.

<3> Next, a laminate composed of the first substrate 2, the first electrode 3, and the semiconductor electrode 4, and the second substrate 7
Then, the laminate including the second electrode 6 is joined via the wall 5 so as to form the storage space 8.

First, the outer edge (periphery) of the semiconductor electrode 4 is
For example, it is surrounded by the material of the wall portion 5 made of an epoxy resin or the like.

Next, a laminated body composed of the first substrate 2, the first electrode 3 and the semiconductor electrode 4 and a laminated body composed of the second substrate 7 and the second electrode 6 are combined with the semiconductor electrode 4 and the second
Are arranged and laminated so that the electrodes 6 face each other.
Is solidified (hardened) and joined. Thereby, the storage space 8 is formed.

An opening for forming an electrolyte gel 81 described later is formed in a part of the wall 5 in the storage space 8.

<4> Next, through the opening of the wall 5,
An electrolyte gel 81 is formed in the storage space 8.

An example of a method for forming the electrolyte gel 81 will be described below. In the following description, the constituent materials of the gel base material (<4A> when the gel base material is mainly made of a thermoplastic resin, <4B> when the gel base material is mainly made of a thermosetting resin, 4C> when the gel base material is mainly composed of a polymer, and <4D> when the gel base material is mainly composed of a compound having a siloxane bond). The description is omitted.

<4A>: When the gel base material is mainly composed of a thermoplastic resin (including the case where only the thermoplastic resin is used)

First, a predetermined amount of a thermoplastic resin is prepared and heated to be melted. When the semiconductor electrode 4 is subjected to a visualization treatment by a dye adsorption method, the melting temperature is lower than the heat resistance temperature of the dye.
For example, the temperature is preferably about 150 ° C. or less,
The temperature is more preferably about 120 ° C. In other words, when a dye is adsorbed on the semiconductor electrode 4, it is preferable to select a thermoplastic resin having a melting temperature within the above range.

Next, an electrolyte solution prepared in the above-mentioned concentration range is added to the melt so as to have the above-mentioned weight ratio and mixed.

Next, the mixture (composition before gelling the electrolyte gel) is injected into the storage space 8 through the opening formed in the wall 5.

The viscosity of the mixture is not particularly limited, but is preferably, for example, about 10 cP or less, more preferably about 5 cP or less. By setting the viscosity of the mixture within the above range, the handling of the mixture can be further facilitated, and the mixture can be more reliably permeated into the holes 41 of the semiconductor electrode 4. As a result, the mixture can penetrate (reach) to the deep part of the hole 41 of the semiconductor electrode 4, so that the obtained electrolyte gel 81 can more reliably increase the contact area with the semiconductor electrode 4.

Next, the mixture injected into the storage space 8 is cooled to obtain the electrolyte gel 81.

That is, when the gel base material is mainly composed of a thermoplastic resin, the thermoplastic resin itself functions as a gelling agent for gelling the electrolyte solution.

As described above, when the gel base material is mainly composed of a thermoplastic resin, there is an advantage that conductivity in a low temperature region is improved and a difference in temperature characteristics of power generation efficiency can be reduced.

When the gel base is mainly composed of a thermoplastic resin, the thermoplastic resin and the electrolyte solution may be, for example, methanol, ethanol, acetone, ethyl acetate,
After mixing (dissolving) in an organic solvent (organic solvent) such as isopropyl alcohol, acetonitrile, and butyl acetate, and then injecting the mixture into the storage space 8, the organic solvent is volatilized to obtain the electrolyte gel 81. it can.

Further, when the gel base material is mainly made of a thermoplastic resin, first, the gel base material is formed in a sponge-like (porous state) in the storage space 8, and then the electrolyte solution is added to the gel base material. The electrolyte gel 81 can also be obtained by making it permeate (doping) by contact.

<4B>: When the gel base material is mainly composed of a thermosetting resin (including the case where only the thermosetting resin is used)

First, a predetermined amount of a precursor of a thermosetting resin is prepared, and the precursor of the thermosetting resin and the electrolyte solution prepared in the above concentration range are blended so as to have the above-mentioned weight ratio. And mix.

Next, the mixture is injected into the storage space 8 through the opening formed in the wall 5.

Next, the mixture injected into the storage space 8 is heated. Thereby, a crosslinking reaction occurs in the precursor of the thermosetting resin in the mixture, and the electrolyte gel 81 can be obtained.

That is, when the gel base material is mainly composed of a thermosetting resin, the precursor of the thermosetting resin functions as a gelling agent for gelling the electrolyte solution.

Since the gel base material is mainly composed of a thermosetting resin, the gel base material is prevented from reversibly returning to the state before gelation, so that the electrolyte solution can be more securely held. Can be.

Since such a thermosetting resin is excellent in heat resistance, the heat resistance of the electrolyte gel 81 can be further improved by forming the gel base material mainly from the thermosetting resin, Deterioration and deterioration due to a temperature rise accompanying the irradiation of light are suppressed.

[0184] The mechanical strength of the electrolyte gel 81 can be further improved by forming the gel base material mainly from a thermosetting resin.

From the above, in the solar cell 1A,
Excellent durability can be exhibited.

<4C>: When the gel base material is mainly composed of a polymer (including the case of only a polymer)

First, a predetermined amount of a polymer precursor is prepared.
The precursor of the polymer and the electrolyte solution prepared in the above-mentioned concentration range are blended and mixed so as to have the above-mentioned weight ratio.

Incidentally, various additives such as a polymerization initiator, a polymerization accelerator, a polymerization retarder, and a polymerization terminator may be added to the mixture as needed.

Next, the mixture is injected into the storage space 8 through the opening formed in the wall 5.

Next, the mixture injected into the storage space 8 is subjected to processing such as heating, pressurizing, and UV irradiation. Thereby, a polymerization reaction occurs in the precursor of the polymer in the mixture, and the electrolyte gel 81 can be obtained.

That is, when the gel base material is mainly composed of a polymer, the precursor of the polymer functions as a gelling agent for gelling the electrolyte solution.

The polymer is preferably obtained mainly by ionic polymerization. Since the polymerization reaction by ionic polymerization is relatively little affected (inhibited) by the electrolyte component, a polymer can be formed more quickly and reliably. Therefore, when the polymer is formed mainly by ionic polymerization, there is an advantage that the electrolyte gel 81 can be obtained more reliably.

When the gel base material is mainly composed of a polymer, the gel base material is prevented from reversibly returning to the state before gelation, so that the electrolyte solution can be held more reliably.

Since such a polymer is excellent in heat resistance, the heat resistance of the electrolyte gel 81 can be further improved by mainly constituting the gel base material with the polymer, and the gel base can be formed by the irradiation of light. Deterioration and deterioration due to temperature rise are suppressed.

Further, when the gel base material is mainly composed of a polymer, the mechanical strength of the electrolyte gel 81 can be further improved.

From the above, in the solar cell 1A,
Excellent durability can be exhibited.

<4D>: When the gel base material is mainly composed of a compound having a siloxane bond (including the case of only a compound having a siloxane bond).

First, a predetermined amount of a precursor of a compound having a siloxane bond is prepared, and the precursor of the compound having a siloxane bond and the electrolyte solution prepared in the above-mentioned concentration range are adjusted to the above-mentioned weight ratio. And mix.

Incidentally, a catalyst (for example, an acid catalyst, a peroxide, platinum or the like) may be added to the mixture as required.

Then, the mixture is injected into the storage space 8 through the opening formed in the wall 5.

Next, the mixture injected into the storage space 8 is left at room temperature. Thereby, a crosslinking reaction (for example, a condensation reaction, an addition reaction, or the like) occurs in the precursor of the compound having a siloxane bond in the mixture, and the electrolyte gel 81 can be obtained.

That is, when the gel base material is mainly composed of a compound having a siloxane bond, the precursor of the compound having a siloxane bond functions as a gelling agent for gelling the electrolyte solution.

Since the gel base material is mainly composed of a compound having a siloxane bond, the gel base material is prevented from reversibly returning to the state before gelation, so that the electrolyte solution is more reliably held. be able to.

Since such a compound having a siloxane bond is excellent in heat resistance, the heat resistance of the electrolyte gel 81 can be further improved by forming the gel base material mainly from a compound having a siloxane bond. In addition, deterioration and deterioration due to a temperature rise due to light irradiation are suppressed.

Further, by forming the gel base material mainly from a compound having a siloxane bond, the electrolyte gel 81
Can be further improved in mechanical strength.

[0206] Therefore, in the solar cell 1A,
Excellent durability can be exhibited.

Through the above steps, the electrolyte gel 81
Is obtained. Next, the opening of the wall 5 is sealed to complete the solar cell 1A.

<Second Embodiment> Next, a second embodiment of the solar cell of the present invention will be described.

FIG. 3 is a sectional view showing a second embodiment of the solar cell of the present invention. Hereinafter, the solar cell 1B shown in FIG. 3 will be described focusing on differences from the first embodiment,
The description of the same items is omitted.

[0210] In the solar cell 1B of the second embodiment, mainly,
The difference is that the electrolyte solution 82 is stored as an electrolyte in the storage space 8 and that the wall 5 is formed integrally with the first substrate 2. The same is true.

As the electrolyte solution 82, a solution prepared by dissolving the same electrolyte components as those described in the first embodiment in the same solvents as those described in the first embodiment is used. Can be.

In this case, the concentration (content) of the electrolyte component in the electrolyte solution 82 can be the same as that in the first embodiment.

[0213] The amount of the electrolyte solution 82 is not particularly limited, and can be appropriately set depending on, for example, the dimensions of the solar cell 1B to be manufactured, the concentration of the electrolyte component, and the like.

Further, in the solar cell 1B of the present embodiment, the electrolyte solution 82 is stored in the storage space 8, but by integrally forming the wall 5 and the first substrate 2, the solar cell 1B Liquid leakage from the side surface of 1B can be more reliably prevented.

Further, from the viewpoint of preventing liquid leakage, the wall 5
The first substrate 2 is preferably made of a material having resistance to ultraviolet rays. Thereby, in particular, the wall 5
, And deterioration with time due to irradiation of light (particularly, ultraviolet light) can be more reliably prevented. For this reason, in the solar cell 1B, liquid leakage is more reliably prevented, and its performance is more reliably maintained over a long period of time, that is, durability is further improved.

Examples of such a material include silicone resin, various glass materials, polycarbonate and the like. Among them, silicone resin and various glass materials are particularly preferable because of their excellent resistance to ultraviolet rays. Materials are preferred.

In the solar cell 1B, the wall 5 and the first substrate 2 are integrally formed, and the first electrode 3 is formed inside the wall 5. Therefore, in such a solar cell 1B, the height (thickness) of the wall portion 5 is set in consideration of the thickness of the first electrode 3.

Further, the wall portion 5 is replaced with the first substrate 2,
It may be formed integrally with the second substrate 7.

In the present embodiment, the wall 5 and the first substrate 2 are formed integrally, but the wall 5 and the first substrate 2 are formed by different members. Is also good. In this case, the wall portion 5 is made of a material having resistance to ultraviolet rays as described above, and the first substrate 2 is made of the same material as that of the first substrate 2 of the first embodiment. Can be.
Even in the case of such a configuration, in the solar cell 1B, the liquid leakage can be suitably prevented, and the durability can be excellent.

In the solar cell 1B, as the electrolyte,
Instead of the electrolyte solution 82, a gel electrolyte having the same configuration as the electrolyte gel 81 of the first embodiment or a solid electrolyte can be used.

Although the solar cell of the present invention has been described based on the illustrated embodiments, the present invention is not limited to these embodiments. Each component constituting the solar cell can be replaced with an arbitrary component having the same function.

The solar cell of the present invention may be a combination of any two or more of the first and second embodiments.

[0223]

Next, specific examples of the present invention will be described.

Example 1 A solar cell shown in FIG. 1 was manufactured as follows.

First, two quartz glass substrates (a first substrate and a second substrate) having dimensions of 10 mm long × 13 mm wide × 1.0 mm thick were prepared. Next, these quartz glass substrates were immersed in a cleaning liquid (a mixed liquid of sulfuric acid and hydrogen peroxide solution) at 85 ° C. to perform cleaning, and the surfaces thereof were cleaned.

-1- On the upper surfaces of these quartz glass substrates, a size: 10 mm × 1
An ITO electrode (first electrode) and a platinum electrode (second electrode) of 3 mm × 1 μm thickness were formed.

2-2 Next, on the upper surface of the formed ITO electrode, a semiconductor electrode having a size of 9 mm long × 9 mm wide × 10 μm thick was formed. This was performed as follows.

[Preparation of Titanium Oxide Powder] Titanium oxide powder comprising a mixture of rutile type titanium dioxide powder and anatase type titanium dioxide powder was prepared. The average particle size of the titanium oxide powder was 40 nm, and the mixing ratio of the rutile type titanium dioxide powder and the anatase type titanium dioxide powder was 60:40 by weight.

[Preparation of Coating Solution (Semiconductor Electrode Material)] First, 50 g of the prepared titanium oxide powder was added to 100 m of distilled water.
L.

Next, nitric acid (stabilizer) 5 was added to the suspension.
0 mL was added and kneaded sufficiently in an agate mortar.

Then, 100 mL of distilled water was added to the suspension.
And further kneaded. By the addition of distilled water, the mixing ratio of nitric acid and water was finally adjusted to 20:80 (volume ratio). At this time, the viscosity of the suspension was 5
cP.

Next, a nonionic surfactant ("Triton-X100", manufactured by ICN Biomedical) was added to the suspension so as to have a final concentration of 3% by weight and kneaded. Thus, a coating liquid (semiconductor electrode material) was prepared.

[Formation of Semiconductor Electrode] After a semiconductor electrode material was applied on the upper surface of the ITO electrode by dipping (coating method), baking (heat treatment) was performed at a temperature of 300 ° C. for 2 hours to obtain a film. .

Next, the laminated body of the quartz glass substrate, the ITO electrode and the film was immersed in ethanol in which carbon black was suspended, and the ethanol was volatilized by natural drying. After drying in a clean oven for an hour, it was left overnight. Thus, a semiconductor electrode having carbon black adsorbed on the surface of the film and in the pores was obtained.

The obtained semiconductor electrode has a porosity of 3
4%, and the surface roughness Ra of the light receiving surface was 0.43 μm.

-3- Next, the periphery of the semiconductor electrode is surrounded by epoxy resin (material of the wall portion), and the quartz glass substrates are arranged so that the semiconductor electrode and the platinum electrode face each other.
After lamination, the epoxy resin was solidified.

An opening for forming an electrolyte gel in the storage space is formed in a part of the wall.

-4- Next, an electrolyte gel was formed in the storage space. First, lithium iodide and iodine (electrolyte component) are each added to ethylene glycol by 0.6 watts.
An iodine solution (electrolyte solution) was prepared by dissolving t% and 3.5 wt%.

Next, polyethylene oxide (thermoplastic resin) was prepared and heated to 70 ° C. to be melted. In addition,
Polyethylene oxide has a weight average molecular weight of 15
00 was used.

The melt and the iodine solution were blended and mixed at a weight ratio of 1: 5. The viscosity of the mixture was 3 cP.

Next, 5 μL of the mixture was injected into the storage space through the opening in the wall, and then cooled to room temperature to obtain an electrolyte gel.

-5-5 Next, the opening of the wall was sealed with an epoxy resin to complete a solar cell.

Example 2 A solar cell was manufactured in the same manner as in Example 1 except that the constituent material of the gel base material was changed to a polyimide resin (thermosetting resin).

A precursor of the polyimide resin (pyromellitic anhydride: paraphenylenediamine = 1: 1) and an iodine solution were blended and mixed at a weight ratio of 1: 5, and mixed.
The viscosity of the mixture was 3 cP.

Next, 5 μL of the mixture was injected into the storage space through the opening in the wall, and then heated to 120 ° C. to obtain an electrolyte gel.

Example 3 A solar cell was manufactured in the same manner as in Example 1 except that the constituent material of the gel base material was changed to a vinyl ether copolymer (ion copolymer).

A precursor of a vinyl ether copolymer (divinyl ether: maleic anhydride = 1: 1) and an iodine solution were blended in a weight ratio of 1: 9 and mixed.
Further, a sulfonium salt was added as a polymerization initiator in an amount of 0.1 wt% in the mixture. The viscosity of such a mixture is
It was 2 cP.

Next, 5 μL of the mixture was injected into the storage space through the opening in the wall, and then irradiated with ultraviolet rays of 500 mW / cm ² at a wavelength of 360 nm for 30 seconds to obtain an electrolyte gel.

Example 4 A solar cell was manufactured in the same manner as in Example 1 except that the constituent material of the gel base material was changed to a vinylmethylsilanol copolymer (a compound having a siloxane bond).

A precursor of vinylmethylsilanol copolymer (prepolymer: weight average molecular weight: about 2,000) and an iodine solution were blended and mixed at a weight ratio of 1: 9. Also, platinum was added to the mixture as a catalyst.
The viscosity of the mixture was 1 cP.

Next, 5 μL of this mixture was injected into the storage space through the opening in the wall, and then left at room temperature to obtain an electrolyte gel.

Example 5 A solar cell shown in FIG. 3 was manufactured as follows.

First, a quartz glass substrate having dimensions of 10 mm (length) × 13 mm (width) × 1.0 mm (thickness) and having a wall formed in the center (a first substrate integrally formed with a wall);
Dimensions: A quartz glass substrate (second substrate) having a length of 10 mm, a width of 13 mm, and a thickness of 1.0 mm was prepared.

Next, these quartz glass substrates were immersed in a cleaning liquid (a mixed liquid of sulfuric acid and hydrogen peroxide solution) at 85 ° C. for cleaning to clean the surface.

-1'- On the upper surface (inside of the wall) of the quartz glass substrate on which the wall was formed, the size: 9 m long
m × 9 mm × 1 μm thick ITO electrode (first electrode)
Was formed.

On the other hand, on the upper surface of the other quartz glass substrate, a size: 10 mm long × 13 mm wide × 1 μm thick was formed by vapor deposition.
m platinum electrodes (second electrodes) were formed.

Next, a semiconductor electrode having a size of 9 mm long × 9 mm wide × 10 μm thick was formed on the upper surface of the formed ITO electrode. This was obtained in the same manner as in Example 1.

-3'- Next, an electrolyte solution was injected
μL was supplied, and then the quartz glass substrates were arranged and joined so that the semiconductor electrode and the platinum electrode faced each other. The electrolyte solution was prepared in the same manner as in Example 1.

Example 6 A solar cell was manufactured in the same manner as in Example 5 except that a silicon resin substrate having a wall was used instead of the quartz glass substrate having a wall. The electrolyte solution was prepared in the same manner as in Example 1.

Comparative Example A solar cell was manufactured in the same manner as in Example 1 except that an electrolyte solution was used instead of the electrolyte gel.

An electrolyte solution was prepared in the same manner as in Example 1, and 5 μL was supplied into the wall.

(Experiment) Each of the solar cells manufactured in Examples 1 to 6 and Comparative Example was continuously irradiated with ultraviolet light having a wavelength of 350 nm for 2 weeks using an ultraviolet irradiation device.

(Evaluation) Before and after the above experiment, the solar cells of Examples 1 to 6 and Comparative Example were irradiated with light of artificial sun lamps, respectively, and the photoelectric conversion efficiency at this time was measured. The incident angle of light on the semiconductor electrode is 9
The angle was set to 0 ° and 52 °, and the photoelectric conversion efficiency when the light incident angle was 90 ° was R _90, and the photoelectric conversion efficiency when 52 ° was R ₅₂ . Table 1 shows the results of this evaluation.

[0264]

[Table 1]

From the results shown in Table 1, all of the solar cells of the present invention (Examples 1 to 6) were excellent in photoelectric conversion efficiency, and even after the experiment of irradiating ultraviolet rays. The photoelectric conversion efficiency was maintained.

On the other hand, in the solar cell of the comparative example, after the experiment of irradiating the ultraviolet rays, the leakage of the liquid was considered to be caused by the deterioration of the wall, and the measurement of the photoelectric conversion efficiency was impossible. .

Further, the solar cell of the present invention (Examples 1 to 3)
6) In any case, R ₅₂ / R ₉₀ is 0.85 or more,
This indicated that the solar cell of the present invention had lower directivity to light.

[0268]

As described above, according to the present invention, a solar cell which is prevented from leaking and has excellent durability can be obtained.

The solar cell of the present invention has low directivity and is excellent in power generation efficiency (photoelectric conversion efficiency).

The solar cell of the present invention is easy to manufacture and can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a solar cell (photocell) of the present invention.

FIG. 2 is a cross-sectional view near a light receiving surface of a semiconductor electrode.

FIG. 3 is a sectional view showing a second embodiment of the solar cell of the present invention.

[Explanation of symbols]

 Reference Signs List 1A, 1B solar cell 2 first substrate 3 first electrode 4 semiconductor electrode 41 hole 5 wall 6 second electrode 7 second substrate 8 storage space 81 electrolyte gel 82 electrolyte solution 9 external circuit

Continued on the front page F term (reference) 5F051 AA14 AA20 FA02 FA03 FA04 GA03 GA05 5H032 AA06 AS07 AS09 AS10 AS16 CC06 CC11 CC16 EE04 EE07 HH01 HH04

Claims (24)

[Claims] 1. A semiconductor electrode mainly composed of titanium oxide and an electrolyte are interposed between an anode and a cathode such that the semiconductor electrode is located on the cathode side and the electrolyte is located on the anode side. A solar cell, wherein a gel electrolyte is used as the electrolyte. 2. The solar cell according to claim 1, wherein the gel electrolyte holds an electrolyte solution in a gel base material. 3. The solar cell according to claim 2, wherein the gel base is mainly composed of a thermoplastic resin. 4. The solar cell according to claim 2, wherein the gel base is mainly composed of a thermosetting resin. 5. The solar cell according to claim 2, wherein the gel base is mainly composed of a copolymer obtained by polymerizing at least two kinds of compounds. 6. The solar cell according to claim 5, wherein the copolymer is obtained mainly by ionic polymerization. 7. The solar cell according to claim 2, wherein the gel base is mainly composed of a compound having a siloxane bond. 8. The gel electrolyte, wherein a constituent material of the gel base material and the electrolyte solution are in a weight ratio of 1: 1 to 1: 1.
The solar cell according to claim 2, wherein the content of the solar cell is 50. 9. The solar cell according to claim 1, further comprising a wall member that covers the periphery of the semiconductor electrode and the electrolyte. 10. A semiconductor electrode mainly composed of titanium oxide and an electrolyte are interposed between an anode and a cathode such that the semiconductor electrode is located on the cathode side and the electrolyte is located on the anode side, A solar cell in which the periphery of the semiconductor electrode and the electrolyte is covered with a wall member, wherein the wall member is made of a material having resistance to ultraviolet rays. 11. The solar cell according to claim 10, wherein the material is a silicone resin or a glass material. 12. The solar cell according to claim 10, further comprising a substrate supporting at least one of the anode and the cathode, wherein the wall member is formed integrally with the substrate. 13. A semiconductor electrode and an electrolyte mainly composed of titanium oxide are interposed between an anode and a cathode such that the semiconductor electrode is located on the cathode side and the electrolyte is located on the anode side, A solar cell in which the periphery of the semiconductor electrode and the electrolyte is covered with a wall member, comprising a substrate that supports at least one of the anode and the cathode, wherein the wall member is formed integrally with the substrate. A solar cell. 14. The solar cell according to claim 13, wherein the wall member and the substrate are made of a material having resistance to ultraviolet rays. 15. The solar cell according to claim 14, wherein the material is a silicone resin or a glass material. 16. The solar cell according to claim 1, wherein said titanium oxide is mainly composed of titanium dioxide. 17. The semiconductor electrode has an average particle diameter of 1 nm.
The solar cell according to claim 1, wherein the solar cell is manufactured using a titanium oxide powder having a thickness of 1 μm to 1 μm. 18. The solar cell according to claim 1, wherein the semiconductor electrode is porous. 19. The semiconductor electrode according to claim 1, wherein the porosity is 5 to 90.
The solar cell according to claim 18, wherein the percentage is%. 20. The semiconductor electrode according to claim 1, wherein the surface roughness Ra is 5
The solar cell according to claim 18, wherein the thickness is from 10 nm to 10 μm. 21. The solar cell according to claim 1, wherein the semiconductor electrode has a film shape. 22. The semiconductor electrode having an average thickness of 0.1
22. The solar cell according to claim 21, which has a thickness of from about 300 m to about 300 m. 23. The solar cell according to claim 1, wherein the semiconductor electrode has been subjected to a visualization process capable of absorbing light having a wavelength in a visible light region. 24. An incident angle of light on the semiconductor electrode is 90.
The photoelectric conversion efficiency in °₉₀And the incident angle of light is 52 °
The photoelectric conversion efficiency of R₅₂And R₅₂/ R ₉₀Is 0.8
The sun according to any one of claims 1 to 23, which is the above.
battery.