JP5319951B2 - Solar cell - Google Patents

Description

  The present invention relates to a solar cell. In particular, the present invention relates to a solar cell having an electrode substrate on which a conductive layer containing single-walled carbon nanotubes and fullerenes is provided.

Solar cells using carbon nanotubes as electrode films have attracted attention.
For example, a dye-sensitized solar characterized in that a nanocarbon film made of fibrous carbon having a diameter of nanometer size selected from the group of single wall carbon nanotubes, multiwall carbon nanotubes, and carbon nanofibers is used as an electrode. A battery has been proposed (Japanese Patent Application Laid-Open No. 2004-111216).

  Further, a dye-sensitized solar cell electrode substrate having a transparent substrate and a transparent electrode formed on one side of the transparent substrate, the transparent electrode being formed on the transparent substrate, For example, a transparent first conductive layer made of a metal oxide such as ITO or ZnO, a second conductive layer made of a metal such as Pt, Au, or Ni formed on the first conductive layer, and the second For a dye-sensitized solar cell, comprising a third conductive layer formed on a conductive layer, for example, one or two or more carbons selected from the group consisting of fullerenes, fullerene derivatives and carbon nanotubes An electrode substrate, a photoelectrode substrate having a porous semiconductor electrode made of semiconductor fine particles having a dye supported on the surface, a counter electrode substrate disposed opposite to the photoelectrode substrate, the photoelectrode substrate, and the counter electrode substrate, Electrolyte intervening between A dye-sensitized solar cell comprising: a dye-sensitized solar cell, wherein the photoelectrode substrate is the electrode substrate for a dye-sensitized solar cell (Japanese Patent Application Laid-Open No. 2005-2005). 142088).

In a solar cell in which a p-type semiconductor material and an n-type semiconductor material are pn-junction or pin-junction, the p-type semiconductor material or the n-type semiconductor material is in a state where a plurality of carbon nanotubes are electrically connected to each other. A solar cell characterized in that it is composed of a structure film arranged in the manner described above has been proposed (Japanese Patent Laid-Open No. 2006-237204).
JP-A-2004-111216 JP2005-142088 JP 2006-237204 A

  Now, all of the proposed techniques have left problems in terms of durability and the like.

  Therefore, the problem to be solved by the invention is to provide a solar cell with low cost and high durability.

The above issues are
A solar cell having an electrode substrate provided with at least a conductive layer on the substrate,
The conductive layer is solved by a solar cell including single-walled carbon nanotubes and fullerenes.

  In particular, the above solar cell is a single-walled carbon nanotube in which single-walled carbon nanotubes are entangled with each other.

  In addition, the above solar cell is solved by a solar cell characterized in that the single-walled carbon nanotube is a single-walled carbon nanotube by an arc discharge method.

  Moreover, it is solved by the solar cell described above, wherein the fullerene is a fullerene hydroxide.

  Furthermore, in the above-described solar cell, the problem is solved by the solar cell characterized in that the conductive layer is formed without using a binder resin.

  Moreover, it is solved by the solar cell described above, wherein the electrode substrate is made of resin.

  Moreover, it is said solar cell, Comprising: A solar cell characterized by providing a protective layer on a conductive layer is solved.

  Moreover, it is a solar cell characterized by being a solar cell of the type using the oxidation-reduction reaction of a pigment.

  Since the conductive layer of the solar cell electrode substrate is composed of single-walled carbon nanotubes and fullerenes, it has excellent conductivity and durability, and the conductive layer can be easily configured. High quality and high durability solar cells can be obtained at a low cost.

  In Patent Document 1, carbon nanotubes are used for electrodes of solar cells. However, a solar cell with high durability cannot be obtained only by using carbon nanotubes. That is, with the thing of patent document 1, the feature which this invention show | plays cannot fully be show | played.

  The thing of patent document 2 describes using 1 type, or 2 or more types of carbon chosen from the group which consists of fullerene, a fullerene derivative, and a carbon nanotube. However, in this method, the conductive layer of the electrode substrate is made of, for example, a transparent first conductive layer made of a metal oxide such as ITO or ZnO, and formed on the first conductive layer, for example, Pt, Au, Ni. A second conductive layer made of metal such as, and a third conductive layer formed on the second conductive layer, for example, one or two or more carbons selected from the group consisting of fullerenes, fullerene derivatives, and carbon nanotubes And a three-layer laminated conductive layer. For this reason, the flexibility of the conductive layer is lacking. For example, when a resin film or a resin sheet is used as the substrate, the above-mentioned hard conductive layer cannot follow such a flexible substrate, and damage is likely to occur. That is, the durability is inferior. Furthermore, as a result of research by the present inventor, it was found that the latter is more durable when only the carbon nanotubes are used in the conductive layer and when the carbon nanotubes and fullerenes are used in combination. It is. Patent Document 2 describes “a third conductive layer made of one or more carbons selected from the group consisting of fullerenes, fullerene derivatives and carbon nanotubes”, and details of the invention of the specification In the description column, for example, paragraph number [0044], “fullerene, fullerene derivative or carbon nanotube is preferably used” is described, and “combination of carbon nanotube and fullerene” is not described at all. . Furthermore, even in the examples describing the best mode of the invention, there is no description of “combination of carbon nanotubes and fullerenes”. Moreover, in the thing of patent document 2, binder resin is used for the structure of a conductive layer, As a result, electroconductivity falls. Furthermore, since the conductive layer has a three-layer structure, the cost is high.

  In Patent Document 3, carbon nanotubes are used for solar cells, but carbon nanotubes are not used for the conductive layer of the electrode substrate.

  The present invention is a solar cell. In particular, the solar cell includes an electrode substrate in which at least a conductive layer is provided on the substrate. The conductive layer includes single-walled carbon nanotubes and fullerenes. That is, a conductive layer is configured by using single-walled carbon nanotubes and fullerenes in combination. In particular, the single-walled carbon nanotubes are intertwined single-walled carbon nanotubes. Due to this entanglement, the single-walled carbon nanotubes are electrically connected at a plurality of locations. The single-walled carbon nanotube is particularly preferably a single-walled carbon nanotube obtained by an arc discharge method. The fullerene is particularly preferably a fullerene hydroxide. The conductive layer is composed of a single-walled carbon nanotube and fullerene. In this case, the conductive layer is particularly preferably composed of no binder resin. The substrate of the electrode substrate is particularly preferably made of resin. Preferably, a protective layer is provided on the conductive layer. A solar cell of the type utilizing a redox reaction of a dye is preferable.

Further details will be described below.
The present invention is a solar cell that requires a conductive layer. For example, a solar cell using an indirect transition type semiconductor such as a dye-sensitized solar cell, a single crystal silicon solar cell, another crystal silicon solar cell, or an amorphous silicon solar cell can be given. _{Further, CuInSe 2 (CIS), Cu} (In, Ga) solar cell using a direct transition type semiconductor such as Se ₂ (CIGS) can also be mentioned. However, a dye-sensitized solar cell is particularly preferable.

  There is no particular limitation on the layer structure of the solar cell. For example, in a dye-sensitized solar cell, the layer configuration of transparent substrate / transparent electrode layer / photocatalyst layer / electrolyte layer / transparent electrode layer / substrate is exemplified. In the silicon-based solar cell, a layer configuration of transparent substrate / transparent electrode / p-type semiconductor / n-type semiconductor is given as an example. In the CIS solar cell, the layer configuration of substrate / electrode / light absorption layer / buffer layer / transparent electrode layer / antireflection layer is an example.

  In addition, as above-mentioned, this invention is used suitably for a dye-sensitized solar cell. Therefore, in the following, the dye-sensitized solar cell will be described in detail.

  Two substrates are required. At least one of the two substrates is required to have optical transparency. Specifically, the total light transmittance is 80% or more and 100% or less. And preferably, a sheet form or a film form is used.

  There are no particular restrictions on the material of the substrate. For example, ceramic such as glass can be used. In addition, thermoplastic resins such as polyester resin, cellulose resin, vinyl alcohol resin, vinyl chloride resin, cycloolefin resin, polycarbonate resin, acrylic resin, and ABS resin can be used. In addition, a photocurable resin, a thermosetting resin, etc. are mentioned. In addition, from the viewpoint of flexibility, it is preferably made of resin.

  The thickness of the substrate depends on the application. In the case of a sheet shape, it is, for example, 500 μm to 10 mm. In the case of a film shape, it is, for example, 10 μm to 500 μm.

For the photocatalyst layer, oxides such as anatase type titanium oxide, rutile type titanium oxide, zinc oxide, tin oxide, and nibismuth trioxide are used. Among these, sol-like anatase-type titanium oxide TiO ₂ is preferable. This is because sol-like anatase-type titanium oxide TiO ₂ forms an extremely smooth surface when the other side in contact with the TiO ₂ is hydrophilic.

The film thickness of the photocatalyst layer is preferably 0.01 μm to 10 μm when anatase TiO ₂ is used. This is because when the film thickness is less than 0.01 μm, problems such as coating defects such as pinholes are likely to occur. Conversely, if the film thickness exceeds 10 μm and becomes too thick, the transmittance decreases.

The photocatalyst layer is formed by forming (or adsorbing) a dye layer made of a ruthenium complex on the surface of titanium oxide TiO ₂ . Such a dye may be any substance that has an improved absorption function in the wavelength range of sunlight. For example, chlorophyll or rhodamine can be used.

A redox redox solution is used for the electrolyte layer. Specifically, a couple of anions that rapidly change between different oxidation states depending on light irradiation and electron supply can be used as the electrolyte. Examples of the anion couple having such a property include halogen couples such as iodine (I ⁻ / I ³⁻ ), bromine (Br ²⁻ / Br ⁻ ), and chlorine (ClO ⁻ / Cl ⁻ ). The degree of ionization is I>Br> Cl. The electrolytic solution may be used by impregnating a porous material represented by cloth, paper or the like.

Hereinafter, the conductive layer of the solar cell according to the present invention will be described.
The conductive layer in the present invention includes single-walled carbon nanotubes and fullerenes.
This single-walled carbon nanotube may be obtained by any manufacturing method. For example, an arc discharge method, a chemical vapor method, a laser evaporation method, or the like can be used. However, from the viewpoint of crystallinity, those obtained by a production method using an arc discharge method are preferred. And this thing is also easy to obtain.

  The single-walled carbon nanotube used in the present invention is preferably a single-walled carbon nanotube subjected to acid treatment. The acid treatment is to bring the acidic liquid into contact with the single-walled carbon nanotube. For example, the single-walled carbon nanotube is immersed in an acidic liquid. Or it is the process which sprays an acidic liquid on a single-walled carbon nanotube. There are no particular restrictions on the acidic liquid used. An inorganic acid or an organic acid can be used as appropriate. Specific examples include nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, and mixtures thereof. It is preferable to use nitric acid or a mixed solution of nitric acid and sulfuric acid. And as for the conditions of an acid treatment, it is preferable that temperature is 80 to 100 degreeC, and it is preferable that time is 1 day-7 days. When the single-walled carbon nanotube and the carbon fine particles are physically bonded through the amorphous carbon by such acid treatment, the two are separated by the decomposition of the amorphous carbon. In addition, the fine particles of the metal catalyst used when producing the single-walled carbon nanotube are decomposed. As a result, the conductivity is improved. That is, when the acid treatment is compared with the case where the acid treatment is not performed, the former has improved conductivity.

  The single-walled carbon nanotube used in the present invention is preferably filtered. That is, the impurities are removed by filtration, the purity is improved, and the decrease in conductivity and the decrease in light transmittance can be prevented. There is no particular limitation on the filtration method. For example, suction filtration, pressure filtration, cross flow filtration, or the like can be used. However, cross-flow filtration using a hollow fiber membrane is preferable from the viewpoint of scale-up.

  It is essential that the conductive layer comprising the single-walled carbon nanotube of the present invention contains fullerene or an analog thereof. This is because the durability is improved as compared with a conductive film not containing fullerene or an analog thereof.

  Any fullerene may be used in the present invention. For example, C60, C70, C76, C78, C82, C84, C90, C96 etc. are mentioned. Of course, a mixture of these fullerenes may be used. C60 is particularly preferable from the viewpoint of dispersion performance. Furthermore, C60 is easy to obtain. Further, not only C60 but also a mixture of C60 and another kind of fullerene (for example, C70) may be used. Further, metal atoms may be appropriately included in the fullerene. The analogs include those having a known functional group such as hydroxyl group, epoxy group, ester group, amide group, sulfonyl group, ether group, phenyl-C61-propyl acid alkyl ester, phenyl-C61-butyric acid alkyl ester. And hydrogenated fullerene. Among these, those having an OH group (hydroxyl group) are particularly preferable. This is because the single-walled carbon nanotubes are highly dispersible when applied as a dispersion. In addition, when there is little quantity of a hydroxyl group, the dispersibility improvement degree of a single-walled carbon nanotube will fall. On the other hand, if too much, synthesis is difficult. Accordingly, the amount of hydroxyl groups is preferably 5 to 30 per molecule of fullerene. In particular, 8 to 15 is preferable.

  If the amount of fullerene added is too large, the conductivity is lowered. On the other hand, if the amount is too small, the effect is difficult to occur. Therefore, the amount of fullerene is preferably 10 to 1000 parts by mass with respect to 100 parts by mass of single-walled carbon nanotubes. Particularly, it is preferably 20 to 100 parts by mass with respect to 100 parts by mass of the single-walled carbon nanotube.

  In the present invention, the conductive layer composed of single-walled carbon nanotubes is a structure in which single-walled carbon nanotubes are entangled with each other. As a result, the single-walled carbon nanotubes come into contact with each other, in particular, in contact with each other at a plurality of locations, and electrical conduction is good. Whether the single-walled carbon nanotubes are intertwined can be confirmed by observing the surface of the conductive layer with a scanning electron microscope.

  In the present invention, a protective layer may be further provided on the conductive layer made of single-walled carbon nanotubes and fullerene. There is no particular restriction on the material used for this protective layer. For example, a thermoplastic resin such as a polyester resin, a cellulose resin, a vinyl alcohol resin, a vinyl resin, a cycloolefin resin, a polycarbonate resin, an acrylic resin, or an ABS resin is used. In addition, a photo-curable resin, a thermosetting resin such as a silicon-based or epoxy-based resin, or the like can also be used. In addition, it is preferable that the material of a protective layer is the same material as a board | substrate from an adhesive viewpoint. For example, when the substrate is a polyester resin, the protective layer is also preferably a polyester resin. If the protective layer is too thick, the contact resistance of the transparent conductive layer increases. On the other hand, if it is too thin, the function as a protective layer is not achieved. Accordingly, the thickness of the protective layer is preferably 1 nm to 1 μm. More preferably, it is 10 nm-100 nm.

  The conductive layer preferably has a total light transmittance of 60% to 100%. The surface resistance value is preferably 10Ω / □ to 1000Ω / □ or less. This is because if the total light transmittance is too low, the power generation is reduced. Note that a conductive layer using single-walled carbon nanotubes has a trade-off relationship between the total light transmittance and the surface resistance value. Therefore, the surface resistivity is preferably higher as long as the solar cell operates.

  In addition, solar cells other than dye-sensitized solar cells can use the conductive layer by the above-described method.

The solar cell of the present invention can be produced by the following steps.
Step 1: Obtaining crude carbon nanotubes Step 2: Acid treatment step of treating crude carbon nanotubes with acid Step 3: Filtration step of filtering single-walled carbon nanotubes obtained in Step 2 Step 4: Single-walled carbon nanotubes and solvent Step 5: Dispersion step by ultrasonic irradiation Step 5: Applying the single-walled carbon nanotube dispersion obtained in Step 4 on the substrate Step 6: Applying the photoelectric conversion layer on the electrode substrate obtained in Step 5 Step of Forming The above steps 1 to 6 are preferably performed in this order.

Hereinafter, each process will be described in more detail.
[Step 1]
There are no particular restrictions on the method of obtaining the crude carbon nanotube. Any manufacturing method such as an arc discharge method, a chemical vapor phase method, or a laser evaporation method can be used. However, it is preferable to use an arc discharge method from the viewpoint of crystallinity. And this thing is also easy to obtain.

[Step 2]
The step of acid-treating the crude carbon nanotube is a step of heating the single-walled carbon nanotube in an acidic liquid. There are no particular restrictions on acidic liquids. For example, nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid and a mixture thereof can be used. Nitric acid or a mixed acid of nitric acid and sulfuric acid is preferably used. The heating temperature is 80 ° C to 100 ° C. The heating time is 1 day to 7 days.

[Step 3]
This step is a step of filtering the single-walled carbon nanotubes obtained in step 2. Thereby, impurities such as carbon particles are removed. That is, the reaction solution of carbon nanotubes subjected to the acid treatment is dispersed (or precipitated) in the solution in a state where, for example, impurity particles having a diameter of about 20 nm and carbon nanotube bundles are separated. Therefore, the impurities can be removed by filtering using a filter having a pore size larger than the impurities and smaller than the bundle of carbon nanotubes. Various methods can be employed as the filtration method. For example, suction filtration, pressure filtration, cross flow filtration, or the like can be used. Among these, from the viewpoint of scale-up, cross flow filtration using a hollow fiber membrane is preferable.

[Step 4]
The step of mixing single-walled carbon nanotubes and a solvent and irradiating with ultrasonic waves is a step of producing a dispersion of single-walled carbon nanotubes. In this step, fullerene is added. There are no particular restrictions on the ratio of single-walled carbon nanotubes to fullerenes. However, the fullerene is preferably 10 to 1000 parts by mass with respect to 100 parts by mass of the single-walled carbon nanotube. The fullerene concentration is preferably 1 to 100,000 ppm. The fullerene is preferably a fullerene having a functional group. In particular, fullerene having an OH group is preferable. Various methods can be employed for the method of irradiating ultrasonic waves. For example, a bus type ultrasonic irradiator or a chip type ultrasonic irradiator can be used. From the viewpoint of processing in a shorter time, it is preferable to use a chip-type ultrasonic irradiator. There is no special restriction | limiting in the solvent used by this invention. However, a solvent having a boiling point of 200 ° C. or lower (preferably lower limit is 25 ° C., further 30 ° C.) is preferable. The low boiling point solvent is preferred because it is easy to dry after coating. Specifically, water, alcohol compounds such as methanol, ethanol, normal propanol, and isopropanol (particularly alcohols having 7 or less carbon atoms, especially aliphatic alcohols), or a mixture thereof are preferable. This is because the hydroxyl group-containing fullerene has high solubility, and a single-walled carbon nanotube dispersion liquid having a higher concentration can be obtained. In addition, for example, ketone compounds such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ester compounds such as methyl acetate, ethyl acetate, butyl acetate, ethyl lactate, methoxyethyl acetate, diethyl ether, ethylene glycol dimethyl ether, ethyl cellosolve , Ether compounds such as butyl cellosolve, phenyl cellosolve and dioxane, aromatic compounds such as toluene and xylene, aliphatic compounds such as pentane and hexane, halogenated hydrocarbons such as methylene chloride, chlorobenzene and chloroform, and mixtures thereof You can also

[Step 5]
In this step, the single-walled carbon nanotube dispersion obtained in step 4 is applied onto a substrate. That is, it is a step of forming a conductive layer on the substrate. Specifically, it is a step of forming a film of the dispersion liquid on the substrate by using a coating method such as spray coating, bar coating, roll coating, ink jet method, screen coating, die coating or the like. Furthermore, if necessary, drying is performed after the coating step in order to remove the solvent contained in the coating film. As a drying apparatus used, for example, a heating furnace, a far-infrared furnace, a super far-infrared furnace, etc. that are usually used for drying can be used. Furthermore, it is possible to clean the substrate.

[Step 6]
In this step, a photoelectric conversion layer is formed on the electrode substrate obtained in step 5. Depending on the type of the target solar cell, that is, a dye-sensitized solar cell, a silicon-based solar cell, and a CIGS-based solar cell, any known method can be used. In addition, when there exists the process heated in the process 6, it is preferable that it is 1500 degrees C or less. Moreover, it is preferable that it is under inert gas atmosphere, such as nitrogen, neon, and argon. Further, it is preferably in a low pressure or in a vacuum. This is because there is a high risk that the single-walled carbon nanotube is destroyed.

Hereinafter, the present invention will be described with reference to specific examples.
[Example 1]
[Production of electrode substrate]
Single-walled carbon nanotubes produced by the arc discharge method were reacted with 63% nitric acid at 85 ° C. for 2 days. Thereafter, the single-walled carbon nanotubes were purified and collected by filtration.

  10 mg of single-walled carbon nanotubes thus obtained, 10 mg of hydroxyl group-containing fullerene (trade name Nanomuspectra D-100 Frontier Carbon), 1 mg of sodium hydroxide (Wako Pure Chemical Industries), 5 ml of water, After mixing with 5 ml of 2-propanol, ultrasonic irradiation (apparatus name: ULTRASONIC HOMOGENIZER MODEL UH-600SR, manufactured by SMT) was performed for 1 minute to obtain a single-walled carbon nanotube dispersion.

  This single-walled carbon nanotube dispersion was spray-coated on a resin substrate so that the surface resistance was 30Ω / □ (device name: Loresta-FP, manufactured by Dia Instruments). And it was made to dry at 80 degreeC for 3 minute (s), and the transparent conductive layer was formed. The total light transmittance was 63% (device name: direct reading haze computer, manufactured by Suga Test Instruments Co., Ltd.). The coated surface was washed with methanol to obtain an electrode substrate. In addition, when the resistance was measured after being left in an oven at 80 ° C. for 10 days, it was 31Ω / □. That is, it can be seen that the resistance value hardly changes, and the durability is excellent.

[Production of solar cells]
3 g of titanium oxide powder (manufactured by Asahi Sangyo Co., Ltd.), 4 ml of aqueous nitric acid (pH 4), and 13 ml of ethanol were mixed and subjected to ultrasonic irradiation for 1 minute to prepare a titanium oxide dispersion. This titanium oxide dispersion was applied onto the electrode substrate so as to have a film thickness of 50 μm, and dried at room temperature for 5 minutes (see FIG. 1).

  Then, it baked for 30 minutes at 450 degreeC by nitrogen atmosphere with the electric furnace (made by ADVANTEC).

  On the other hand, mallow blue (manufactured by Asahi Sangyo Co., Ltd.) was immersed in distilled water to prepare a mallow blue aqueous solution. Then, the fired electrode was immersed in a mallow blue aqueous solution and adsorbed on the titanium oxide layer.

  Next, the electrode with the titanium oxide layer and the untreated electrode were overlapped so that the electrodes face each other, and two opposing sides were fixed with a room temperature curing type epoxy resin (trade name, manufactured by Quick5 Konishi Co., Ltd.).

  Thereafter, an iodide electrolyte solution (a mixture of 0.5 M potassium iodide solution and 0.05 M iodine solution) was injected between the electrodes to produce a dye-sensitized solar cell (see FIGS. 2 and 3).

  And when the solar cell obtained as described above was irradiated with UV by a UV irradiation device (trade name Toscure 401 manufactured by Harrison Toshiba Lighting Co., Ltd.), the electrical output characteristics were a voltage of 260 mV and a current of 2.1 μA.

[ Reference Example 1 ]
In Example 1, the same procedure was performed except that 0.1 mg of polyvinylpyrrolidone was used as the binder resin when preparing the single-walled carbon nanotube dispersion.
When the durability of the electrode substrate of the solar cell thus obtained was examined, the resistance (30Ω / □) before being left in an oven at 80 ° C. for 10 days was 32Ω / □ after being left in an oven at 80 ° C. for 10 days. In addition, when this solar cell was irradiated with UV by a UV irradiation device, the electric output characteristics were a voltage of 200 mV and a current of 1.8 μA.

[Comparative Example 1]
In Example 1, it carried out similarly except not using a hydroxyl-containing fullerene.
When the durability of the electrode substrate of the solar cell thus obtained was examined, the resistance (30Ω / □) before being left in an oven at 80 ° C. for 10 days was 300Ω / □ after being left in an oven at 80 ° C. for 10 days. It was inferior in durability. Further, when this solar cell was irradiated with UV by a UV irradiation device, the electric output characteristics were a voltage of 40 mV and a current of 0.3 μA.

Titanium oxide multilayer electrode configuration diagram (top view) Solar cell configuration (top view) Solar cell configuration diagram (cross section)

Explanation of symbols

1 Titanium oxide layers 2 and 4 Transparent electrode substrate 3 Epoxy resin 5 Electrolyte solution


Patent applicant Kuraray Co., Ltd.
Representative Katsumi Udaka

Claims (7)

A solar cell having an electrode substrate provided with at least a conductive layer on the substrate,
The conductive layer includes single-walled carbon nanotubes and fullerene hydroxide ,
The solar cell, wherein the conductive layer is configured without using a binder resin . 2. The solar cell according to claim 1, wherein the single-walled carbon nanotubes are entangled single-walled carbon nanotubes. The solar cell according to claim 1 or 2, wherein the single-walled carbon nanotube is a single-walled carbon nanotube by an arc discharge method. The solar cell according to any one of claims 1 to 3 , wherein the hydroxyl group of the fullerene hydroxide is 5 to 30 per molecule . The solar cell according to claim 1, wherein the electrode substrate is made of resin. The solar cell according to claim 1, wherein a protective layer is provided on the conductive layer. It is a solar cell using the oxidation-reduction reaction of a pigment | dye, The solar cell in any one of Claims 1-6 characterized by the above-mentioned.