WO2008047641A1 - Composition for electrode formation and method for forming electrode by using the composition - Google Patents

Abstract

Disclosed is a composition for electrode formation, wherein metal nanoparticles are dispersed in a dispersion medium. The composition contains one or more organic polymers selected from the group consisting of polyvinylpyrrolidones, copolymers of polyvinylpyrrolidones, polyvinyl alcohols and cellulose ethers.

Description

 Specification

 Electrode forming composition and electrode forming method using the composition

 Technical field

 The present invention relates to an electrode forming composition, a method of forming an electrode using this composition, a solar cell electrode, an electronic paper electrode, a solar cell, and an electronic paper obtained by the above method. Is.

 This application (October 2006, November 11, 2006, Japanese Patent Application No. 2006—277228 filed, February 2007, 2007, Japanese Patent Application No. 2007—35650, and Claimed priority based on Japanese Patent Application No. 2007-258311 filed in Japan on October 2, 2007, the contents of which are incorporated herein by reference.

 Background art

 [0002] Currently, research and development of clean energy is underway from the standpoint of environmental protection. Among them, solar cells are attracting attention because of their infinite and non-polluting sunlight. Conventionally, monocrystalline or polycrystalline silicon has been frequently used for photovoltaic power generation using solar cells. However, these silicons used in solar cells require a lot of energy and time for crystal growth, and complicated processes are required in the subsequent manufacturing process, making it difficult to increase mass production efficiency. It was difficult to provide low-cost solar cells.

 [0003] On the other hand, so-called thin film semiconductor solar cells (hereinafter referred to as thin film solar cells) using a semiconductor such as amorphous silicon have a semiconductor layer as a photoelectric conversion layer formed on an inexpensive substrate such as glass or stainless steel. It is sufficient to form as many as necessary. Therefore, this thin-film solar cell is considered to become the mainstream of future solar cells because it is thin and light, inexpensive to manufacture, and easy to increase in area.

 [0004] However, thin-film solar cells have not been used in earnest until now because their conversion efficiency is lower than that of solar cells using crystalline silicon. Various measures are currently being taken to improve the performance of thin-film solar cells.

One of them is the back side of the photoelectric conversion layer, that is, the thin film thickness which is one of the fields of application of the present invention. It is to improve the reflection characteristics of light from the back electrode of the positive battery. As a result, sunlight that has not been absorbed by the photoelectric conversion layer can be returned to the photoelectric conversion layer, and sunlight that has not been absorbed can be used effectively.

 In particular, in order to efficiently absorb light in a long wavelength region with low energy into the photoelectric conversion layer, a surface structure having a concavo-convex shape of several tens of nanometers to a micron size is formed on the back electrode, so-called texture structure. It is very effective. Light that reaches the back electrode without being completely absorbed by the photoelectric conversion layer is scattered and reflected by the back electrode having this textured structure, changes its direction, and enters the photoelectric conversion layer again. This scattering increases the optical path length, and the light is effectively confined in the solar cell due to the total reflection condition. This so-called light confinement effect promotes light absorption in the photoelectric conversion layer and improves the conversion efficiency of the solar cell. The light confinement effect is now an indispensable technology for improving the efficiency of solar cells.

 [0007] As shown in FIG. 5, a super straight type solar cell 110 in which light is incident from the translucent substrate side usually includes a substrate 111—a transparent electrode 112—an amorphous Si layer 113a and a microcrystalline Si layer 113b. In order to achieve the light scattering and light confinement effect, it is common to use a transparent electrode 112 on the light incident side, such as SnO, for example, in order to achieve the light scattering and light confinement effects. The light confinement effect is expressed by forming the texture structure 112a in the light and causing light scattering. Note that in this super straight type solar cell, the surface badge badge of the photoelectric conversion layer 113, the ohmic contact with the back electrode 115, and the transparent reflection between the photoelectric conversion layer 113 and the back electrode 115 due to the increased reflection optical design. A conductive film 114 is formed.

 On the other hand, as shown in FIG. 6, in the substrate type solar cell 20 in which light is incident from the surface of the photoelectric conversion layer, the substrate 121—the back electrode 122—the amorphous Si layer 123a and the microcrystalline Si layer 123b are usually used. It consists of a photoelectric conversion layer 123 and a transparent electrode 124 in this order. In general, the back electrode 122 is formed with a textured structure 122a to cause light scattering, thereby producing a light confinement effect. I am letting.

[0009] As a method of forming a back electrode having a texture structure of this substrate type solar cell, a method of polycrystallizing a metal film by heating during vapor deposition (see, for example, Patent Document 1) Teru. ), After vapor deposition 'heat treatment and sputter etching (see, for example, Patent Document 2), after heating during deposition promotes local aggregation of silver and forms a semi-continuous film with irregularities A method of forming a continuous film by evaporating silver at a low temperature (see, for example, Patent Document 3), an Al—Si alloy or the like is deposited while heating the substrate, and an uneven film is formed. A method of depositing a metal film having a high reflectance on the substrate (for example, see Patent Document 4), and a method of forming an uneven film by depositing an AgAl alloy (for example, see Patent Document 5). Each has been proposed.

Patent Document 1: Japanese Patent Laid-Open No. 03-99477 (page 6, upper left column, line 19 to page 6, upper right column, line 3)

Patent Document 2: Japanese Patent Laid-Open No. 03-99478 (Claims (1))

Patent Document 3: Japanese Patent Laid-Open No. 04-218977 (Claim 2, paragraphs [0019] to [0020], FIG. 1)

Patent Document 4: Japanese Patent Laid-Open No. 04 334069 (paragraph [0014])

Patent Document 5: Japanese Unexamined Patent Publication No. 2005-2387 (paragraph [0062])

Disclosure of the invention

Problems to be solved by the invention

However, the conventional method for forming a back electrode having a texture structure of a super straight type solar cell is based on a vacuum film formation method, and requires a vacuum process. There was a big problem. In addition, it has been studied to form the back electrode 115 by applying and baking using a conductive paste. However, as a conventionally known conductive paste, flaky silver particles are added and mixed with a binder such as an acrylic resin, a butyl acetate resin, an epoxy resin or a polyester resin, a solvent, a curing agent, a catalyst, and the like. The silver paste obtained. Therefore, the coating film obtained we were using a paste having such a common conductive, force resistivity (volume resistivity) to have the have the adhesion to the substrate is 10 ⁴ to; 'and the order of cm, resistivity 1 · ⁶ X 10- 6 Ω metallic silver' 10- ⁵ Omega Ri Contact become 10-100 times cm, sufficient conductivity is a problem that has not been obtained. In addition, a space (gap) such as an air layer may be formed at the interface between the transparent conductive film 114 and the back electrode 115. Transparent When such a space is formed at the interface between the conductive film 114 and the back electrode 115, the light that has reached is confined in the space, causing attenuation due to scattering and absorption of light into the metal. As a result, the conversion efficiency is significantly reduced.

[0011] In addition, the conventional method for forming a back electrode having a texture structure of a substrate type solar cell is based on a vacuum film forming method as described in Patent Documents 1 to 5 above. For this reason, since a vacuum process is necessary, there have been major problems with respect to process restrictions or the running cost of manufacturing equipment.

 [0012] In recent years, research and development of electronic paper, which is expected as a next-generation display device, has been actively conducted. Electronic paper is a collective term for display devices that have extreme ease like paper, and as shown in FIG. 7, an operation layer 133 is formed on a base material 131 with a transparent conductive film 132 interposed therebetween. One having a structure in which an electrode layer 134 is bonded to the interface 133 is known.

 [0013] However, when the electrode layer 134 is formed on the surface of the working layer 133 using a conductive paste such as a conventional silver paste, the working layer 133 and the electrode layer 134 are not bonded in the sintering process by firing. There was a problem that unevenness (space) occurred at the joint interface. For this reason, in the electrode layer formed using the conventional conductive paste, the electric field concentration occurs due to the generated unevenness, and the electric field concentration occurs! /, Where it occurs! /, What! /, Where This is not suitable for electronic paper because it causes a difference in operation.

 [0014] An object of the present invention is to provide a space such as a fine air layer at the bonding interface between the transparent conductive film and the back electrode without requiring a vacuum process during film formation when forming the back electrode of the superstrate solar cell. A composition suitable for forming an electrode that can be controlled so as not to form an electrode, a method of forming an electrode using this composition, a solar cell electrode obtained by the above method, and a solar cell It is to provide.

[0015] Another object of the present invention is that a vacuum process is not required at the time of film formation when forming the back electrode of a substrate type solar cell, and a good texture structure can be formed. A composition suitable for forming an electrode capable of controlling the surface roughness and shape, a method for forming an electrode using this composition, a solar cell electrode obtained by the method, a solar cell To provide a battery. [0016] Still another object of the present invention is to use an electrode-forming composition capable of smoothing a bonding interface with an operating layer when forming an electrode layer of electronic paper, and the composition. It is an object of the present invention to provide a method for forming an electrode, an electrode for electronic paper obtained by the method, and electronic paper.

 [0017] Still another object of the present invention is to provide a reflectance close to the reflectance of the metal constituting the metal nanoparticle contained in the composition, and the metal constituting the metal nanoparticle contained in the composition. Provided is an electrode-forming composition capable of obtaining an electrode having a specific resistance close to / and having a specific resistance and excellent adhesion, and a method of forming an electrode using this composition Talk to your child.

 Means for solving the problem

[0018] A first aspect of the present invention is an electrode-forming composition in which metal nanoparticles are dispersed in a dispersion medium, wherein polybulurpyrrolidone (hereinafter referred to as PVP) and PVP are co-polymerized in the composition. An electrode-forming composition comprising one or more organic polymers selected from the group consisting of a coalesced polybutyl alcohol (hereinafter referred to as PVA) and cellulose ether.

 [0019] The content of the organic polymer may be 0.;! To 20% by mass of the metal nanoparticles.

 [0020] The metal nanoparticles may contain 75% by mass or more of silver nanoparticles.

 [0021] The metal nanoparticles may be chemically modified with a protective agent for an organic molecular main chain having a carbon skeleton of 1 to 3 carbon atoms.

[0022] The metal nanoparticles include a number average of metal nanoparticles having a primary particle size in the range of 10 to 50 nm.

Contains 0% or more!

[0023] The metal nanoparticles contain 75% by mass or more of silver nanoparticles and are made of gold, platinum, palladium, ruthenium, nickel, copper, tin, indium, zinc, iron, chromium and manganese. 1 type of particles selected from the above or particles of a mixed composition or alloy composition of 2 or more types, and the content of particles other than silver nanoparticles contained in the metal nanoparticles is 0.02% by mass or more 25 It may be less than% by mass! /.

[0024] The dispersion medium may be an alcohol, or! /, Or an alcohol-containing aqueous solution.

[0025] The electroforming composition comprises a metal oxide, a metal hydroxide, an organometallic compound, and silicon. It may further contain one or more additives selected from the group consisting of green oil.

 [0026] The metal oxide includes at least one selected from the group consisting of aluminum, silicon, titanium, chromium, manganese, iron, cobalt, nickel, silver, copper, zinc, molybdenum, tin, indium and antimony. It may be an oxide or a complex oxide.

 [0027] The metal hydroxide is at least one selected from the group consisting of aluminum, silicon, titanium, chromium, manganese, iron, cobalt, nickel, silver, copper, zinc, molybdenum, tin, indium and antimony. It may be a hydroxide containing.

 [0028] The organometallic compound may be a metal sarcophagus, metal complex or metal alkoxide of silicon, titanium, chromium, manganese, iron, cobalt, nickel, silver, copper, zinc, molybdenum and tin.

 [0029] In a second aspect of the present invention, there is provided a step of coating one of the electrode forming compositions described above on a base material by a wet coating method, and a base material formed on the upper surface. And a step of firing at 130 to 400 ° C.

 [0030] The thickness of the fired electrode formed on the upper surface of the substrate may be in the range of 0.;! To 2.0 m.

 [0031] The average surface roughness of the electrode formed on the upper surface of the substrate may be in the range of 10 to! OOnm.

 [0032] The substrate is made of silicon, glass, ceramics including a transparent conductive material, a substrate made of a polymer material or a metal, or ceramics including a silicon, glass, or a transparent conductive material, a polymer material, and a metal. It may be two or more kinds of laminates selected from the group of! /,

Yes

 [0033] The substrate may be either a solar cell element or a solar cell element with a transparent electrode.

[0034] The wet coating method is any one of a spray coating method, a dispenser coating method, a spin coating method, a knife coating method, a slit coating method, an inkjet coating method, a screen printing method, an offset printing method or a die coating method. It may be. [0035] A third aspect of the present invention is a solar cell electrode obtained by any of the electrode forming methods described above.

 [0036] A fourth aspect of the present invention is an electrode for electronic paper obtained by any one of the electrode forming methods described above.

[0037] The solar cell electrode is composed of at least a substrate, a back electrode, a photoelectric conversion layer, and a transparent electrode, and has a substrate structure formed in the order of the substrate, the back electrode, the photoelectric conversion layer, and the transparent electrode. It may be a back electrode of a solar cell.

 [0038] The solar cell electrode has at least a substrate, a transparent electrode, a photoelectric conversion layer, and a back electrode, and has a super straight type structure formed in the order of the substrate, the transparent electrode, the photoelectric conversion layer, and the back electrode. It may be a back electrode of a solar cell.

 [0039] A fifth aspect of the present invention is a solar cell including any one of the above-described solar cell electrodes.

[0040] A sixth aspect of the present invention is an electronic paper including any of the electronic paper electrodes described above.

 The invention's effect

 [0041] The electrode-forming composition of the present invention does not require a vacuum process during film formation when forming the back electrode of a super straight solar cell, and is fine at the junction interface between the transparent conductive film and the back electrode. It is possible to control such that a space such as a simple air layer is not formed. In addition, a vacuum process is not required at the time of film formation when forming the back electrode of the substrate type solar cell, a good texture structure can be formed, and the average surface roughness and shape of this texture structure can be controlled. Power S can be. In addition, when the electrode layer of the electronic paper is formed, the bonding interface with the operation layer can be smoothed. Furthermore, the reflectance is close to the reflectance of the metal itself constituting the metal nanoparticles contained in the composition, and the specific resistance of the metal itself constituting the metal nanoparticles contained in the composition! It is possible to obtain an electrode having resistance and excellent adhesion.

 Brief Description of Drawings

FIG. 1A is a cross-sectional view showing one embodiment of a manufacturing process of a super straight type solar cell according to the present invention. [FIG. IB] A sectional view showing the manufacturing method of the same embodiment.

FIG. 1C is a cross-sectional view showing the manufacturing method of the same embodiment.

FIG. 1D is a cross-sectional view showing the manufacturing method of the same embodiment.

 FIG. 2A is a cross-sectional view showing one embodiment of a production process of a substrate type solar cell according to the present invention.

 FIG. 2B is a cross-sectional view showing the manufacturing method of the same embodiment.

FIG. 2C is a cross-sectional view showing the manufacturing method of the same embodiment.

FIG. 2D is a cross-sectional view showing the manufacturing method of the same embodiment.

FIG. 3 is a cross-sectional view showing an electronic paper according to the present invention.

 FIG. 4 is a graph showing diffuse reflectance in the coating films obtained in Examples 1 to 7 and Comparative Examples 1 to 3.

 FIG. 5 is a cross-sectional view showing a conventional super straight solar cell.

FIG. 6 is a cross-sectional view showing a conventional substrate type solar cell.

FIG. 7 is a cross-sectional view showing a conventional electronic paper.

Explanation of symbols

 10 Super straight type solar cell

 11 Base material

 12 Transparent electrode

 12a Texture structure

 13 Photoelectric conversion layer

 13a Ammonorefusus Si

 13b Microcrystalline Si

 14 Transparent conductive film

 15 Back electrode

 20 Substrate type solar cell

 21 Base material

 22 Back electrode

22a Texture structure 23 Photoelectric conversion layer

 23a Ammonorefusus Si

 23b Microcrystalline Si

 24 Transparent electrode

 25 Sealant

 30 electronic paper

 31 Substrate

 32 Transparent conductive film

 33 Operation layer

 34 Electrode layer

 BEST MODE FOR CARRYING OUT THE INVENTION

Next, the best mode for carrying out the present invention will be described.

 [0045] The composition for forming an electrode of the present invention is a composition in which metal nanoparticles are dispersed in a dispersion medium.

 The composition of the present invention is characterized in that the composition contains one or more organic polymers selected from the group consisting of PVP, a copolymer of PVP, PVA and cellulose ether. A super-straight type solar cell using this composition containing one or more organic polymers selected from the group consisting of the above-mentioned types containing nitrogen and oxygen in a desired ratio in the composition. By forming the back electrode, it is possible to control grain growth by sintering between metal nanoparticles. If the control is performed in a direction that suppresses the grain growth, unevenness is not generated on the back electrode side of the bonding interface between the transparent conductive film and the back electrode, and a space such as an air layer is not formed.

 [0046] Further, when the back electrode of the substrate type solar cell is formed using this composition, the effect of suppressing the grain growth due to the sintering between the metal nanoparticles is given, so the electrode having a good texture structure is formed. can do. In this case, the average surface roughness and shape of the texture structure can be controlled. Moreover, an electrode using this composition is excellent in adhesion to the substrate.

[0047] The formation of the electrode using the composition of the present invention does not require a vacuum process at the time of film formation, so the process restrictions are small and the running cost of the manufacturing equipment is greatly reduced. And force S.

 [0048] When an electrode layer of electronic paper is formed using this composition, grain growth due to sintering between metal nanoparticles can be controlled. If the control is performed in a direction that suppresses the grain growth, the bonding interface with the operation layer can be smoothed.

 [0049] Further, when an electrode is formed using this composition, it is not as good as when a conventional binder such as a conventional epoxy resin or urethane resin is added! /, But has practically sufficient adhesion. In addition, the reflectance is close to the reflectance of the metal itself constituting the metal nanoparticle contained in the composition and the specific resistance of the metal itself constituting the metal nanoparticle contained in the composition! /, An electrode having a specific resistance is obtained.

 [0050] For example, when an organic polymer having a heterocyclic ring such as PVP is added to the composition, it has an effect of reducing the surface roughness of a coating film formed using the composition. Therefore, by adjusting the addition ratio of the organic polymer, it is possible to form a coating film surface having a desired surface roughness. The content of the organic polymer is selected within the range of 0.;! To 20% by mass of the metal nanoparticles. Among these, although depending on the kind to be added, the content of the organic polymer is more preferably in the range of about 0.2 to 10% by mass. The reason why the content of the organic polymer is in the range of 0.1% to 20% by mass of the metal nanoparticles is that if the content is less than 0.1% by mass, the effect of suppressing the sintering cannot be obtained, and the formed film This is because sufficient adhesion between the substrate and the substrate cannot be obtained, and when the content exceeds 20% by mass, the specific resistance and the reflectance decrease. Specific examples of the PVP copolymer include a PVP-metatalylate copolymer, a PVP-styrene copolymer, and a PVP-butyl acetate copolymer. Moreover, cellulose etc. are mentioned as a cellulose ether.

[0051] When an electrode is formed using a composition that does not contain an organic polymer such as PVP, the surface roughness of the formed electrode increases. However, it is said that there are conditions for optimizing photoelectric conversion efficiency in the uneven shape of the electrode surface, and it is not possible to form an electrode surface with excellent photoelectric conversion efficiency simply by having a large surface roughness. As in the composition of the present invention, it is possible to form a surface having an optimized surface roughness by adjusting the type and concentration of PVP and the like. [0052] The metal nanoparticles contain 75% by mass or more, preferably 80% by mass or more of silver nanoparticles. The reason why the content of silver nanoparticles is in the range of 75% by mass or more with respect to 100% by mass of all metal nanoparticles is that the reflectivity of the electrode formed using this composition is lowered if it is less than 75% by mass. Because it will end up.

 [0053] The above-mentioned metal nanoparticles are preferably chemically modified with an organic molecular main chain protective agent having a carbon skeleton of 1 to 3 carbon atoms. When the composition is applied on the substrate and then baked, the surface of the metal nanoparticles is protected! /, And the organic molecules in the protective agent are detached or decomposed, or! / Are detached and decomposed. This is because an electrode containing a metal residue and a metal as a main component can be obtained without containing an organic residue that substantially affects the conductivity and reflectance of the electrode. The carbon number of the carbon skeleton of the organic molecular main chain of the protective agent that chemically modifies the metal nanoparticles was set in the range of! ~ 3. This is because many organic residues that adversely affect the conductivity and reflectance of the electrode remain in the electrode, which is difficult to decompose (separate and burn).

 Further, the protective agent, that is, the protective molecule chemically modified on the surface of the metal nanoparticle contains a hydroxyl group (one OH) or a carbonyl group (one C═O) and / or one of both. When a hydroxyl group (—OH) is contained in a protective agent that chemically modifies metal nanoparticles such as silver nanoparticles, the composition has excellent dispersion stability and is effective for low-temperature sintering of the coating film. When a carbonyl group (c = o) is contained in a protective agent that chemically modifies metal nanoparticles such as silver nanoparticles, the composition has excellent dispersion stability as described above, and can be used for low-temperature sintering of the coating film. Has an effective action

Yes

[0055] The metal nanoparticles contain 70% or more, preferably 75% or more of the number average of metal nanoparticles having a primary particle size in the range of 10 to 50 nm. The content of metal nanoparticles in the primary particle size range of 10 to 50 nm is more than 70% with respect to 100% of all metal nanoparticles on a number average basis. Since the surface area increases and the proportion of the protective agent increases, even organic molecules that are easily desorbed or decomposed (separated and burned) by the heat during firing, the organic molecules account for a large proportion. This is because a lot of organic residue remains. This residue is altered or deteriorated to decrease the conductivity and reflectance of the electrode, or the particle size distribution of the metal nanoparticles is widened and the density of the electrode is easily decreased. The primary particle size of the above metal nanoparticles within the range of 10-50 nm, which decreases the emissivity, is that the metal nanoparticles with the primary particle size within the range of 10-50 nm are statistically determined by statistical methods. This is because it correlates with stability (aging stability).

[0056] The metal nanoparticles contain 75% by mass or more of silver nanoparticles, and gold, platinum, palladium, ruthenium, nickel, copper, tin, indium, zinc, iron, chromium and manganese. It is preferable to further contain metal nanoparticles composed of one kind of particles selected from the group consisting of two or more kinds of mixed compositions or alloy compositions. The metal nanoparticles other than silver nanoparticles should have a force of 0.02% by mass or more and less than 25% by mass with respect to 100% by mass of all metal nanoparticles, preferably 0.03% by mass to 20% by mass. More preferably. The reason why the content of particles other than silver nanoparticles is in the range of 0.02% by mass to less than 25% by mass with respect to 100% by mass of all metal nanoparticles However, within the range of 0.02% by mass or more and less than 25% by mass, the resistance of the electrode after the weather resistance test (a test held in a constant temperature and humidity chamber at a temperature of 100 ° C and a humidity of 50% for 1000 hours) This is because the conductivity and reflectivity are not deteriorated compared to those before the weather resistance test! /, And! /. On the other hand, if the content is 25% by mass or more, the conductivity and reflectance of the electrode immediately after firing are reduced, and the electrode after the weather resistance test has a lower conductivity and reflectance than the electrode before the weather resistance test. It is.

[0057] The composition may further include one or more additives selected from the group consisting of metal oxides, metal hydroxides, organometallic compounds, and silicone oils. By further adding one or more of the above types of additives to the composition, the effect of further suppressing grain growth due to sintering between metal nanoparticles is given, so a surface shape corresponding to the purpose is created. That power S is possible. The addition ratio of the additive is preferably in the range of 0.;! To 20% by mass with respect to the composition. Of these, the range of 1 to 5% by mass is particularly preferable. If the additive ratio is less than the lower limit, the effect of suppressing grain growth cannot be obtained, and if the additive content exceeds the upper limit, the specific resistance increases significantly. Note that the metal oxide referred to in the present invention includes a metalloid oxide that is not only a metal element oxide. In addition, the metal hydroxide referred to in the present invention includes a metalloid hydroxide which is not only a metal element hydroxide. Similarly, the organometallic compound referred to in the present invention includes not only metal elements but also metalloid elements. As a component.

 [0058] Both the above-mentioned organic polymer and the above-mentioned types of additives are not included! / When an electrode is formed using the composition, the surface roughness of the formed electrode increases. However, it is said that there are conditions for optimizing the photoelectric conversion efficiency in the uneven shape of the electrode surface, and it is not possible to form an electrode surface with excellent photoelectric conversion efficiency simply by having a large surface roughness. As in the composition of the present invention, it is possible to form an optimized uneven shape by adjusting the kind and concentration of the organic polymer and additives.

 [0059] The metal oxide used as the additive is selected from the group consisting of aluminum, silicon, titanium, chromium, manganese, iron, cobalt, nickel, silver, copper, zinc, molybdenum, tin, indium and antimony. In addition, an oxide or composite oxide containing at least one kind is preferable. Specific examples of composite oxides include indium tin oxide (ITO), antimony tin oxide (ATO), and zinc indium oxide. Complex oxide (Indium Zinc Oxide: IZO)

Yes

 [0060] The metal hydroxide used as the additive is selected from the group consisting of aluminum, silicon, titanium, chromium, manganese, iron, cobalt, nickel, silver, copper, zinc, molybdenum, tin, indium and antimony. Hydroxides containing at least one of these are preferred.

 [0061] Examples of the organometallic compound used as the additive include silicon, titanium, chromium, manganese, iron, cobalt, nickel, silver, copper, zinc, molybdenum and tin metal sarcophagus, metal complexes or metal alkoxides. Is preferred. For example, metal sarcophagus includes chromium acetate, manganese formate, iron citrate, cobalt formate, nickel acetate, silver citrate, copper acetate, copper citrate, tin acetate, zinc acetate, zinc oxalate, molybdenum acetate, etc. It is done. Examples of the metal complex include a acetylacetone zinc complex, a acetylacetone chrome complex, and a acetylacetone nickel complex. Metal alkoxides are titanium isopropoxide, methyl silicate.

[0062] As the silicone oil used as an additive, both straight silicone oil and modified silicone oil can be used. Modified silicone oil is more poly Either one of the side chains of the siloxane introduced with an organic group (side chain type), one introduced with an organic group at both ends of the polysiloxane (both ends type), or one of both ends of the polysiloxane One having an organic group introduced (one-end type) and one having a side chain of polysiloxane and an organic group introduced at both ends (both side-chain type) can be used. The modified silicone oil has both a reactive silicone oil and a non-reactive silicone oil, and both types can be used as additives in the present invention. Reactive silicone oil means amino modification, epoxy modification, carboxy modification, carbinol modification, mercapto modification, and heterofunctional modification (epoxy group, amino group, polyether group), and non-reactive silicone. Oil means polyether modification, methylstyryl group modification, alkyl modification, higher fatty acid ester modification, fluorine modification, and hydrophilic special modification.

 [0063] The content of the metal nanoparticles in the electrode-forming composition is preferably 2.5 to 95.0% by mass with respect to 100% by mass of the metal nanoparticle and the dispersion medium that also serves as a dispersion medium. More preferably, the content is 3.5 to 90.0% by mass. The content of metal nanoparticles in the range of 2.5 to 95.0% by mass with respect to 100% by mass of the metal nanoparticle and dispersion medium is less than 2.5% by mass, especially after firing. Although it does not affect the characteristics of the electrode, it is difficult to obtain an electrode of the required thickness. If it exceeds 95% by mass, the required fluidity as an ink or paste will be lost during wet coating of the composition. Because it will end up.

[0064] The dispersion medium constituting the electrode forming composition of the present invention is 1% by mass or more, preferably 2% by mass or more, and 2% by mass or more, with respect to 100% by mass of all the dispersion media. It is preferable to contain 3% by mass or more of alcohols. For example, when the dispersion medium consists only of water and alcohols, when 2% by mass of water is contained, 98% by mass of alcohol is contained, and when 2% by mass of alcohol is contained, 98% by mass of water is contained. . The reason why the water content is preferably in the range of 1% by mass or more with respect to 100% by mass of all the dispersion media was obtained by applying the composition by a wet coating method when it was less than 1% by mass. This is because it is difficult to sinter the film at a low temperature and the conductivity and reflectivity of the electrode after firing are lowered. The content of alcohols is preferably in the range of 2% by mass or more with respect to 100% by mass of all the dispersion media. If the content is less than 2% by mass, the composition is applied by the wet coating method as described above. It is difficult to sinter the resulting film at low temperatures, and the conductivity and reflectivity of the electrode after firing are reduced. The power to do it. The alcohol used in the dispersion medium is one selected from the group consisting of methanol, ethanol, prononor, butanol, ethylene glycol, propylene glycol, jetylene glycol, glycerol, isobornylhexanol and erythritol. Or use two or more!

[0065] The addition of alcohols is for improving the wettability with the base material, and the mixing ratio of water and alcohols can be freely changed in accordance with the type of base material.

[0066] A method for producing the above electrode forming composition is as follows.

[0067] (a) When the carbon skeleton of the organic molecular main chain of the protective agent for chemically modifying the silver nanoparticles is 3

First, silver nitrate is dissolved in water such as deionized water to prepare an aqueous metal salt solution. On the other hand, aqueous sodium citrate having a concentration of 10 to 40% obtained by dissolving sodium taenate in deionized water or the like is added to a granular or powdered sulfuric acid solution in an inert gas stream such as nitrogen gas. Prepare a reducing agent aqueous solution containing citrate ions and ferrous ions in a molar ratio of 3: 2 by adding iron directly. Next, while stirring the reducing agent aqueous solution in the inert gas stream, the metal salt aqueous solution is dropped into and mixed with the reducing agent aqueous solution. Here, by adjusting the concentration of each solution so that the amount of the metal salt aqueous solution added is 1/10 or less of the amount of the reducing agent aqueous solution, even if the metal salt aqueous solution at room temperature is dropped, the reaction temperature is 30 to 30%. Force to keep at 60 ° C S is preferable. In addition, the mixing ratio of the two aqueous solutions is such that the molar ratio of the citrate ion and ferrous ion in the reducing agent aqueous solution to the total valence of the metal ions in the metal salt aqueous solution is 3 times as much as each other. To. After the dropwise addition of the aqueous metal salt solution, the mixture is stirred for an additional 10 to 300 minutes to prepare a dispersion composed of metal colloid. This dispersion is allowed to stand at room temperature, and the aggregates of the precipitated metal nanoparticles are separated by decantation, centrifugation, or the like. Thereafter, water such as deionized water is added to the separated product to form a dispersion, which is desalted by ultrafiltration. Subsequent substitution cleaning with alcohols is performed to adjust the metal (silver) content to 2.5 to 50% by mass. After that, by using a centrifuge to adjust the centrifugal force of this centrifuge and separating coarse particles, silver nanoparticles with a primary particle size in the range of 10 to 50 nm are 70% or more on average. Prepare to contain. That is, the number average of all silver nanoparticles 100% primary particle size within the range of 10-50nm Adjust the silver nanoparticles to 70% or more. As a result, a dispersion having 3 carbon atoms in the carbon skeleton of the organic molecular main chain of the protective agent for chemically modifying the silver nanoparticles can be obtained.

 [0068] Subsequently, the obtained dispersion is adjusted so that the final metal content (silver content) with respect to 100% by mass of the dispersion is in the range of 2.5 to 95% by mass. When the dispersion medium is an aqueous solution containing alcohols, it is preferable to adjust the water and alcohols of the solvent to 1% or more and 2% or more, respectively. Next, one or more organic polymers selected from the group consisting of PVP, a PVP copolymer and cellulose ether are added to the dispersion. The content of the organic polymer is adjusted so as to be in the range of 0.;! To 20% by mass of the metal nanoparticles. As a result, the silver nanoparticles chemically modified with a protective agent for the organic molecular main chain having a carbon number strength of the carbon skeleton are dispersed in the dispersion medium and selected from the group consisting of PVP, PVP copolymer and cellulose ether. In addition, an electrode-forming composition containing one or more organic polymers can be obtained. In addition, one or more additives selected from the group consisting of metal oxides, metal hydroxides, organometallic compounds, and silicone oils may be further included. When the additive is further included, the combined content of the organic polymer and the additive is adjusted to be in the range of 0.;! To 20% by mass with respect to 100% by mass of the obtained composition.

 [0069] (b) When the carbon skeleton of the organic molecular main chain of the protective agent for chemically modifying the silver nanoparticles is 2

 A dispersion is prepared in the same manner as in (a) above, except that sodium citrate used for preparing the reducing agent aqueous solution is replaced with sodium malate. As a result, a dispersion having a carbon number strength of the carbon skeleton of the organic molecular main chain that chemically modifies the silver nanoparticles can be obtained.

[0070] (c) When the carbon skeleton of the carbon skeleton of the organic molecular main chain of the protective agent for chemically modifying the silver nanoparticles is 1

 A dispersion is prepared in the same manner as in the above (a) except that the sodium citrate used for preparing the reducing agent aqueous solution is replaced with sodium glycolate. This gives a dispersion in which the carbon skeleton of the carbon backbone of the organic molecular chain that chemically modifies the silver nanoparticles is one.

[0071] (d) Carbon in the organic molecular main chain of a protective agent for chemically modifying metal nanoparticles other than silver nanoparticles When the skeleton has 3 carbon atoms

 Examples of the metal constituting the metal nanoparticles other than the silver nanoparticles include gold, platinum, palladium, ruthenium, nickel, copper, tin, indium, zinc, iron, chromium and manganese. The silver nitrate used in preparing the metal salt aqueous solution was chloroauric acid, chloroplatinic acid, palladium nitrate, ruthenium trichloride, nickel chloride, cuprous nitrate, tin dichloride, indium nitrate, zinc chloride, iron sulfate, Prepare a dispersion in the same manner as (a) above, except replacing with chromium sulfate or manganese sulfate. As a result, a dispersion in which the carbon skeleton of the carbon skeleton of the organic molecular main chain of the protective agent that chemically modifies the metal nanoparticles other than the silver nanoparticles is obtained.

 [0072] When the number of carbon skeletons of the organic molecular main chain of the protective agent for chemically modifying metal nanoparticles other than silver nanoparticles is 1 or 2, the silver nitrate used when preparing the metal salt aqueous solution A dispersion is prepared in the same manner as in the above (b) and (c) except that is replaced with the above-mentioned metal salt. As a result, a carbon number force of the carbon skeleton of the organic main chain of the protective agent that chemically modifies the metal nanoparticles other than the silver nanoparticles and a dispersion having 2 are obtained.

 [0073] When the metal nanoparticles include metal nanoparticles other than silver nanoparticles together with silver nanoparticles, for example, a dispersion containing silver nanoparticles produced by the method of (a) above is used as the first. When a dispersion containing metal nanoparticles other than silver nanoparticles produced by the method (d) above is used as the second dispersion, 75% by mass or more of the first dispersion and less than 25% by mass of the first dispersion are used. The two dispersions are mixed so that the total content of the first and second dispersions is 100% by mass. Note that the first dispersion is not limited to the dispersion containing the silver nanoparticles produced by the method (a), but the dispersion containing the silver nanoparticles produced by the method (b) or the above (c). It is also possible to use a dispersion containing silver nanoparticles produced by the above method.

 [0074] A method of forming an electrode using the electrode-forming composition thus produced will be described.

[0075] First, the electrode forming composition is coated on a substrate by a wet coating method to form a film. The substrate is made of silicon, glass, ceramics including a transparent conductive material, a substrate made of a polymer material or a metal, or a group consisting of silicon, glass, ceramics including a transparent conductive material, a high molecular material, and a metal. Two or more selected laminates can be used. In addition, a substrate containing at least one of the transparent conductive films or a transparent conductive film is formed on the surface. A filmed substrate may be used. Examples of the transparent conductive film include indium oxide, tin oxide, and zinc oxide. Examples of the indium oxide system include indium oxide, ΙΤΟ, and ΙΖΟ. Examples of tin oxides include nesa (tin oxide SnO), silver, and fluorine-doped tin oxide. Examples of zinc oxides include zinc oxide, cocoon (aluminum-doped zinc oxide), and gallium doped zinc oxide. The substrate is preferably either a solar cell element or a solar cell element with a transparent electrode. Examples of transparent electrodes include ΙΤΟ, ΑΤΟ, Nesa, ΙΖΟ, ΑΖ Ο and the like. Furthermore, a dielectric thin film such as lead zirconate titanate (ΡΖΤ) may be formed on the surface of the base material. Examples of the polymer substrate include a substrate formed of an organic polymer such as polyimide PET (polyethylene terephthalate). The dispersion is applied to the surface of the photoelectric conversion semiconductor layer of the solar cell element or the surface of the transparent electrode of the solar cell element with a transparent electrode.

[0076] Further, the wet coating method includes spray coating method, dispenser coating method, spin coating method, knife coating method, slit coating method, ink jet coating method, screen printing method, offset printing method or die coating method. Any of these methods is particularly preferable, but any method other than this is available.

Yes

 [0077] The spray coating method is a method in which the dispersion is atomized with compressed air and applied to the substrate, or the dispersion itself is pressurized and atomized to apply to the substrate. The dispenser coating method is, for example, a method in which a dispersion is placed in a syringe and the piston of the syringe is pushed to discharge the dispersion from a fine nozzle at the tip of the injector and apply it to a substrate.

 [0078] The spin coating method is a method in which a dispersion is dropped onto a rotating substrate, and the dropped dispersion is spread around the periphery of the substrate by its centrifugal force. In the knife coating method, a base material having a predetermined gap from the tip of the knife is provided so as to be movable in the horizontal direction, and a dispersion is supplied onto the base material upstream from the knife so that the base material faces downstream. It is a method to move horizontally

[0079] The slit coating method is a method in which a dispersion is discharged from a narrow slit and applied onto a substrate. The ink jet coating method is a method in which a dispersion is filled in an ink cartridge of a commercially available ink jet printer and ink jet printing is performed on a substrate. [0080] The screen printing method is a method in which wrinkles are used as a pattern indicating material, and the dispersion is transferred to a substrate through a plate image formed thereon. The offset printing method is a printing method that utilizes the water repellency of ink, in which the dispersion attached to the plate is not directly attached to the substrate, but is transferred from the plate to a rubber sheet and then transferred from the rubber sheet to the substrate again. is there.

 [0081] The die coating method is a method in which the dispersion supplied into the die is distributed by means of a manifold and extruded onto the thin film from the slit, and the surface of the traveling substrate is applied. Die coating methods include slot coating, slide coating, and curtain coating.

 [0082] Next, the substrate formed on the upper surface is heated to 130 to 400 ° C, preferably 170 to 400 ° C for 5 minutes to 1 in the atmosphere or in an inert gas atmosphere such as nitrogen or argon. Bake for an hour, preferably 15-40 minutes. Here, the firing temperature of the electrode-forming composition film formed on the substrate was set in the range of 130 to 400 ° C. If the temperature was less than 130 ° C, the metal nanoparticles were not sufficiently sintered. In addition, it is difficult for desorption or decomposition (separation-combustion) due to heat during firing of the protective agent, so that a large amount of organic residue remains in the electrode after firing. This residue is altered or deteriorated, and the conductivity and reflectivity are lowered. If the temperature exceeds 400 ° C, the low temperature process and the production advantage can be utilized! /. In other words, manufacturing costs will increase and productivity will decrease. In particular, it affects the light wavelength range of photoelectric conversion in amorphous silicon, microcrystalline silicon, or a hybrid silicon solar cell using these. Furthermore, the firing time of the electrode-forming composition film formed on the substrate was set in the range of 5 minutes to 1 hour because, if less than 5 minutes, the metal nanoparticles were not sufficiently sintered and the protective agent was used. This is because it is difficult to desorb or decompose (separate and burn) due to the heat during firing, so that many organic residues remain in the electrode after firing. This residue is altered or deteriorated, and the conductivity and reflectivity of the electrode are lowered. If it exceeds 1 hour, the characteristics are not affected, but the manufacturing cost is increased more than necessary and the productivity is lowered. .

 [0083] The thickness after firing formed on the upper surface of the substrate is 0.;! ~ 2.O ^ m, preferably 0.3 ~; 1.5

It adjusts at the time of film-forming so that it may become in this range. Here, the electrode-forming composition formed on the substrate had a thickness after firing in the range of 0.;! To 2.0 m. The surface resistance of the electrode required for the battery becomes insufficient, and if it exceeds 2.0 0 111, there will be no characteristic defects, but there will be no material if the amount of material used is more than necessary. Because it becomes useless.

 [0084] Since the composition for forming an electrode includes a large amount of metal nanoparticles having a primary particle size of 10 to 50 nm and a relatively large size, the specific surface area of the metal nanoparticles is reduced and the proportion of the protective agent is reduced. As a result, when an electrode is formed using the above composition, the protective agent is desorbed or decomposed by the heat during firing, or is separated and decomposed, so that an organic substance that has a substantial adverse effect on electrical conduction can be obtained. An electrode that does not contain is obtained.

 [0085] By firing under the above conditions, an electrode made of a conductive coating film can be formed on the substrate. The formed conductive coating film has excellent adhesion and does not form a fine air layer or other space at the bonding interface with the base material. Therefore, when it is used as the back electrode of a super straight solar cell, A reduction in conversion efficiency can be suppressed.

 [0086] Further, the formed conductive coating film can control grain growth by sintering between metal nanoparticles, and has a good texture structure when used as a back electrode of a substrate type solar cell. Have. Moreover, the coating film which controlled the average surface roughness and shape of the texture structure by the kind and addition amount of the additive in the composition to be used can be obtained. The electrode made of a conductive coating film formed on the upper surface of the substrate preferably has an average surface roughness in the range of 10 to OOnm. When the average surface roughness is within the above range, the range is suitable for the texture structure of the back electrode constituting the substrate type solar cell. The formed conductive coating film has a specific resistance close to the specific resistance of the metal itself constituting the metal nanoparticles contained in the composition. Moreover, an excellent reflectance close to the reflectance of the metal itself constituting the metal nanoparticles contained in the composition can be obtained.

 [0087] In addition, when the formed conductive coating film is used as an electrode layer of electronic paper, it can smooth the bonding interface with the operating layer, and thus is suitable for electronic paper without causing electric field concentration.

 [0088] As described above, the electrode forming method of the present invention is a method in which the electrode forming composition is wet-coated on a substrate to form a film, and the electrode is formed by a simple process of firing the formed substrate. Can be formed. In this way, since a vacuum process is not required at the time of film formation, the running cost of a manufacturing facility can be significantly reduced with less process restrictions.

[0089] A superstrate solar cell formed using the electrode forming composition of the present invention will be described. First, as shown in FIG. 1A, a transparent conductive film is formed on a substrate 11 by sputtering, vapor deposition, or spray pyrolysis (for example, pyrolysis by spray spraying a tin chloride solution: Nesa glass). ) To form a transparent electrode 12. An example of the base material is a translucent substrate 11 such as glass. This transparent conductive film is formed so that its surface layer has a textured structure 12a in order to exhibit light scattering and light confinement effects. As a material for the transparent conductive film, Nesa glass (SnO type) is generally used.

 Next, as shown in FIG. 1B, the photoelectric conversion layer 13 is formed on the transparent electrode 12 having the texture structure 12a. This photoelectric conversion layer 13 is formed by a plasma CVD method. The texture structure 12 a of the transparent electrode 12 is also reflected in the photoelectric conversion layer 13. In the present embodiment, only the amorphous silicon 13a or the microcrystalline silicon 13b may be used, in which the photoelectric conversion layer 13 is made of amorphous silicon 13a and the microcrystalline silicon 13b is a PIN junction laminated film. A solar cell in which the photoelectric conversion layer 13 is formed from a PIN junction laminated film of amorphous silicon 13a and microcrystalline silicon 13b is called a hybrid type or a tandem type.

 Next, as shown in FIG. 1C, on the photoelectric conversion layer 13, the surface badge base of the photoelectric conversion layer, the ohmic contact with the back electrode 15, and the increased reflection optical design The transparent conductive film 14 is formed by sputtering, vapor deposition, or MOCVD.

 [0093] Finally, as shown in FIG. 1D, the back electrode 15 is formed by applying and baking the electrode forming composition of the present invention on the transparent conductive film 14, thereby forming the back electrode 15 from the translucent substrate side. A super straight type solar cell 10 in which light is incident can be obtained. In the super straight type solar cell 10, the base material 11 serves as a light receiving surface. The formed back electrode 15 has excellent adhesion to the transparent conductive film 14 and does not form a space such as a fine air layer at the bonding interface with the transparent conductive film 14, so that it is possible to suppress a reduction in conversion efficiency. A substrate type solar cell that can be formed into a straight type solar cell using the electrode forming composition of the present invention will be described.

First, as shown in FIG. 2A, the back electrode 22 is formed by applying and baking the electrode forming composition of the present invention on the substrate 21. Examples of the base material 21 include glass and organic films. I can get lost. Since the formed back electrode 22 has an effect of suppressing grain growth by sintering between metal nanoparticles, the surface layer has a texture structure 22a that can effectively exhibit light scattering and light confinement effects. Can be formed.

Next, as shown in FIG. 2B, a photoelectric conversion layer 23 is formed on the back electrode 22 having the texture structure 22a. This photoelectric conversion layer 23 is formed by the plasma CVD method similarly to the photoelectric conversion layer 13 of the super straight type solar cell described above, and the texture structure 22a of the back electrode 22 is reflected.

Next, as shown in FIG. 2C, a transparent conductive film is formed by sputtering, vapor deposition, or spray pyrolysis to form a transparent electrode 24. The material of the transparent conductive film is Nesa glass (SnO series)

) Is common.

 Finally, as shown in FIG. 2D, by forming a sealing material on the transparent electrode 24, a vertical solar cell 20 is obtained. In this substrate type solar cell 20, the sealing material becomes the light receiving surface.

 [0098] An electronic paper formed using the electrode forming composition of the present invention will be described.

In the present embodiment, as shown in FIG. 3, the electronic paper 30 has a transparent conductive film on the base 31.

 An operation layer 33 is formed through 32, and an electrode layer 34 is bonded to the interface of the operation layer 33. Examples of the substrate 31 include glass, an organic polymer film, a plastic film, and an organic polymer film on which a silica thin film is formed. The transparent conductive film 32 is formed by a sputtering method. Examples of the material for the transparent conductive film include indium oxide, tin oxide, and zinc oxide. Examples of indium oxide include indium oxide, IT 0, and IZO. Examples of tin oxides include Nesa (tin oxide SnO), ATO, and fluorine-doped tin oxide. Examples of the zinc oxide system include zinc oxide, AZO (aluminum doped zinc oxide), and gallium doped zinc oxide. For the operation layer 33, various methods such as a microcapsule electrophoresis type, an electropowder fluid type, a cholestic liquid crystal type, and an organic EL have been proposed. The electrode layer 34 is formed by applying and baking the electrode forming composition of the present invention. The electrode layer 34 formed in this manner can smooth the bonding interface with the operation layer 33, and therefore does not cause electric field concentration and is suitable for electronic paper.

Example Next, examples of the present invention will be described in detail together with comparative examples.

 [0101] <Example;! To 7, Comparative example;! To 3>

 First, silver nitrate was dissolved in deionized water to prepare a metal salt aqueous solution having a concentration of 25% by mass. In addition, sodium citrate was dissolved in deionized water to prepare an aqueous sodium citrate solution having a concentration of 26% by mass. In this sodium citrate aqueous solution, granular ferrous sulfate is directly added and dissolved in a nitrogen gas stream maintained at 35 ° C to contain citrate ions and ferrous ions in a molar ratio of 3: 2. An aqueous reducing agent solution was prepared.

 [0102] Next, with the nitrogen gas stream maintained at 35 ° C, the magnetic stirrer stirrer is placed in the reducing agent aqueous solution, and the stirrer is rotated at a rotation speed of lOO rpm, so that the reducing agent aqueous solution is The aqueous metal salt solution was added dropwise to the aqueous reducing agent solution while stirring. Here, the metal salt aqueous solution at room temperature was dropped by adjusting the concentration of each solution so that the amount of the metal salt aqueous solution added to the reducing agent aqueous solution was 1/10 or less of the amount of the reducing agent aqueous solution. The reaction temperature was kept at 40 ° C. The mixing ratio of the reducing agent aqueous solution to the metal salt aqueous solution is 3 times the molar ratio of the citrate ion and ferrous ion in the reducing agent aqueous solution to the total valence of the metal ions in the metal salt aqueous solution. It was made to be a mole.

 [0103] After the addition of the metal salt aqueous solution to the reducing agent aqueous solution is completed, the mixture is continuously stirred for 15 minutes to generate metal particles inside the mixture, and the metal particles are dispersed. A liquid was obtained. The pH of the metal particle dispersion was 5.5, and the stoichiometric amount of metal particles in the dispersion was 5 g / liter.

 [0104] The obtained dispersion was allowed to stand at room temperature, whereby the metal particles in the dispersion were allowed to settle, and the aggregates of the precipitated metal particles were separated by decantation. Deionized water was added to the separated metal agglomerate to form a dispersion, which was desalted by ultrafiltration, and further washed by displacement with methanol to make the metal content 50% by mass.

[0105] Thereafter, the centrifugal force of the centrifuge is adjusted using a centrifuge to separate relatively large metal particles having a particle size exceeding lOOnm, so that a metal having a primary particle size in the range of 10 to 50nm is obtained. The nanoparticles were adjusted so as to contain 71% in number average. That is, the number average of 100% of all metal nanoparticles is occupied by metal nanoparticles in the primary particle size range of 10-50nm. The ratio was adjusted to 71%. The obtained metal nanoparticles consisted of silver nanoparticles, and these silver nanoparticles were chemically modified with a protective agent for an organic molecular main chain having a carbon skeleton of 3 carbon atoms.

 [0106] Next, 10 parts by weight of the obtained metal nanoparticles were dispersed by adding to 90 parts by weight of a mixed solution containing water, ethanol and methanol. Furthermore, by adding the additives shown in the following Table 1 to this dispersion so as to have the ratio shown in Table 1, compositions for application tests of Examples;! To 7 and Comparative Examples;! To 3 were obtained, respectively. .

 <Example 8>

 In the same manner as in Examples 1 to 7, the silver nanoparticles were adjusted so as to contain 71% of silver nanoparticles having a primary particle size of 10 to 50 nm on the average. That is, the first dispersion was obtained by adjusting with a centrifuge so that the ratio of silver nanoparticles having a primary particle diameter of 10 to 50 nm to 71% with respect to 100% of all silver nanoparticles was 71%. On the other hand, the silver nitrate of Example 1 was replaced with palladium nitrate, and dispersions washed with ethanol in the same manner as in Examples 1 to 7 were used. The number of palladium nanoparticles having a primary particle size of 10 to 50 nm was measured. It was adjusted to contain 71% on average. That is, the second dispersion was obtained by adjusting with a centrifuge so that the proportion of the palladium nanoparticles having a primary particle diameter of 10 to 50 nm to the palladium average of 100% was 71%. Next, 77% by mass of the first dispersion and 23% by mass of the second dispersion were adjusted. This dispersion was used in Example 8 and evaluated in the same manner as in Examples 1 to 7. Next, 10 parts by weight of the obtained metal nanoparticles were dispersed by adding and mixing in 90 parts by weight of a mixed solution containing water, ethanol and methanol. Further, as shown in Table 1 below, PV P was added to the dispersion so as to have a ratio of 10.0 mass% shown in Table 1. The silver nanoparticles and palladium nanoparticles in the dispersion were each chemically modified with an organic molecular main chain protective agent having a carbon skeleton of 3 carbon atoms. Furthermore, the protective agent chemically modifying silver nanoparticles and palladium nanoparticles contained a hydroxyl group and a carbonyl group.

 <Example 9>

In the same manner as in Examples 1 to 7, the silver nanoparticles were adjusted so as to contain 71% of silver nanoparticles having a primary particle size of 10 to 50 nm on the average. In other words, the number average of silver nanoparticles with a primary particle size of 10-50 nm to 100% of all silver nanoparticles is 71%. To obtain a first dispersion. On the other hand, instead of ruthenium trichloride instead of silver nitrate in Example 1, a dispersion that was washed with ethanol in the same manner as in Examples 1 to 7 was used to obtain ruthenium nanoparticles with ruthenium nanoparticles having a primary particle size of 10 to 50 nm. It was adjusted to contain 71% on average. That is, the second dispersion was obtained by adjusting with a centrifuge so that the ratio of the ruthenium nanoparticles having a primary particle size of 10 to 5 Onm to 72% of the ruthenium nanoparticles with respect to 100% of all the ruthenium nanoparticles was 72%. Next, 77% by mass of the first dispersion and 23% by mass of the second dispersion were adjusted. This dispersion was used in Example 9 and evaluated in the same manner as in Examples 1 to 7. Next, 10 parts by weight of the obtained metal nanoparticles were dispersed by adding and mixing in 90 parts by weight of a mixed solution containing water, ethanol and methanol. Furthermore, as shown in Table 1 below, PVP was adjusted by adding PVP at a ratio of 10.0% by mass shown in Table 1. The silver nanoparticles and ruthenium nanoparticles in the dispersion were each chemically modified with a protective agent of an organic molecular main chain with a carbon skeleton of 3 carbon atoms. Furthermore, the protective agent that chemically modified silver nanoparticles and ruthenium nanoparticles contained hydroxyl and carbonyl groups.

[0109] <Comparison test 1>

 The coating test compositions obtained in Examples;! To 9 and Comparative Examples;! To 3 were applied by spin coating or spray coating to a thickness of 600 nm on the substrate shown in Table 1 below. did. Then, the conductive coating film was formed on the base material by baking in the air under the heat treatment conditions shown in Table 1 below. The formed conductive coating film was evaluated for adhesion to the substrate and coating film reflectance. In addition, the specific resistance of the conductive film formed was determined.

[0110] The adhesion to the substrate was evaluated by a method based on JIS K 5600-5-6 (cross-cut method) and evaluated qualitatively. Specifically, when no significant peeling occurred in the coating film, that is, when the peeling classification was in the range of 0 to 2, it was evaluated as “good”, and the others were evaluated as “bad”. For the evaluation of the reflectance of the coating film, the diffuse reflectance of the coating film was measured by a combination of an ultraviolet-visible spectrophotometer and an integrating sphere. Figure 4 shows the measurement results. In addition, a relative evaluation was made based on the measurement results. Specifically, when the diffuse reflectance of Comparative Example 1 in which no additive was added to the coating test composition was used as a reference value, and the diffuse reflectance was improved from this reference value, it was evaluated as “good”. If the value is almost the same as the reference value, When it was worse than the reference value, it was evaluated as “bad”. The specific resistance of the coating film is determined by measuring the surface resistance of the coating film by a four-probe method, and measuring the film thickness of the coating film by a scanning electron microscope (SEM). Calculated from the film thickness. The results are shown in Table 1, respectively.

 [table 1]

 As can be seen from FIG. 4, the composition of the present invention is compared to Comparative Example 1 in which no additive is added to the composition and Comparative Examples 2 and 3 in which a resin such as urethane or acrylic is added to the composition. In Examples 1 to 7 in which PVP, a PVP copolymer or cellulose ether was added to the product, it was high and diffuse reflectance was obtained at all measured wavelengths.

 [0112] As is clear from Table 1, in Comparative Example 1 in which no additive was added to the composition, the adhesion strength S with the substrate S was inferior. In Comparative Examples 2 and 3 in which a resin such as urethane or acrylic was added to the composition, the adhesion with the base material and the specific resistance of the coating film were excellent. It was confirmed that the reflectance was inferior.

[0113] On the other hand, either PVP, a copolymer of PVP, or cellulose ether is added to the composition. The added examples;! To 9 showed excellent adhesion to any kind of substrate. Moreover, excellent reflectance was obtained in Examples;! To 7, and reflectances equivalent to the reference values were obtained in Examples 8 and 9, respectively. Depending on the type to be added to the composition, additives may be added. It was found that the reflectance did not decrease. Furthermore, a specific resistance close to that of metallic silver was obtained, and the coating film formed using the composition of the present invention was highly! It was.

 [0114] A coating film having such properties is suitable for use as a solar cell electrode.

 <Examples 10 to 21, Comparative Example 4>

 First, a metal salt solution that forms metal nanoparticles shown in Table 2 below was dissolved in deionized water to prepare an aqueous metal salt solution. Further, sodium citrate was dissolved in deionized water to prepare a sodium citrate aqueous solution having a concentration of 6 mass%. In this aqueous sodium citrate solution, granular ferrous sulfate is directly added and dissolved in a nitrogen gas stream maintained at 35 ° C., and the molar ratio of citrate ions and ferrous ions is 3: 2. An aqueous reducing agent solution was prepared.

 [0116] Next, with the nitrogen gas stream maintained at 35 ° C, the magnetic stirrer stirrer is placed in the reducing agent aqueous solution, and the stirrer is rotated at a rotation speed of lOOrpm, thereby reducing the reducing agent aqueous solution. The aqueous metal salt solution was added dropwise to the aqueous reducing agent solution while stirring. Here, the metal salt aqueous solution at room temperature was dropped by adjusting the concentration of each solution so that the amount of the metal salt aqueous solution added to the reducing agent aqueous solution was 1/10 or less of the amount of the reducing agent aqueous solution. The reaction temperature was kept at 40 ° C. The mixing ratio of the reducing agent aqueous solution to the metal salt aqueous solution is 3 times the molar ratio of the citrate ion and ferrous ion in the reducing agent aqueous solution to the total valence of the metal ions in the metal salt aqueous solution. It was made to be a mole. After the addition of the aqueous metal salt solution to the reducing agent aqueous solution is completed, stirring of the mixed solution is further continued for 15 minutes to generate metal particles inside the mixed solution, thereby obtaining a metal particle dispersion liquid in which the metal particles are dispersed. It was. The pH of the metal particle dispersion was 5.5, and the stoichiometric amount of metal particles in the dispersion was 5 g / liter.

[0117] The obtained dispersion was allowed to stand at room temperature, so that the metal particles in the dispersion were allowed to settle, and the aggregates of the precipitated metal particles were separated by decantation. Deionized water is added to the separated metal agglomerates to form a dispersion, which is desalted by ultrafiltration, and then further treated with methanol. By substitution cleaning, the metal content was adjusted to 50% by mass. Then, using a centrifuge, the centrifugal force of the centrifuge is adjusted to separate relatively large metal particles with a particle size exceeding lOOnm. Was adjusted to contain 71% in number average. That is, the proportion of metal nanoparticles in the primary particle size range of 10 to 50 nm with respect to 100% of all metal nanoparticles was adjusted to 71% on a number average. The resulting metal nanoparticles were chemically modified with a protective agent for an organic molecular main chain having a carbon skeleton of 3 carbon atoms.

 [0118] Next, 10 parts by weight of the obtained metal nanoparticles were dispersed by adding and mixing in 90 parts by weight of a mixed solution containing water, ethanol and methanol, and the addition shown in Table 2 below was further added to this dispersion. The composition for application | coating test of Examples 10-21 and the comparative example 4 was obtained by adding a thing so that it might become a ratio shown in Table 2, respectively.

 [0119] <Comparison test 2>

The composition for coating test obtained in Examples 10 to 21 and Comparative Example 4 was coated on the base materials shown in Table 2 by various film forming methods so as to have a film thickness of 10 ² to 2 X 10 nm. did. Then, the conductive coating film was formed on the base material by baking under the heat treatment conditions shown in Table 2 below.

 [0120] With respect to the formed conductive coating film, specific resistance, reflectance, coating film thickness and average surface roughness were determined. The specific resistance of the coating film was calculated by measuring the surface resistance of the coating film by the four-probe method, measuring the film thickness of the coating film by SEM, and calculating from the measured surface resistance and film thickness. The reflectance of the coating film was evaluated by measuring the diffuse reflectance of the coating film at a wavelength of 800 nm using a combination of an ultraviolet-visible spectrophotometer and an integrating sphere. The coating thickness was measured by cross-sectional observation with SEM. The average surface roughness was obtained by evaluating the evaluation value regarding the surface shape obtained by an atomic force microscope (AFM) according to JIS B0601. The results are shown in Table 3, respectively.

[0121] [Table 2]

[ε 挲] [ζζ \ ϋ]

0SL690 / L00Zdf / 13d 63 9_ So-called 00 OAV Resistivity [Ω 'cm] Reflectivity (800nm) [] Coating thickness [nm] Average surface roughness [nm] Actual 10 3.1X10— ⁶ 95 1.0X10 ² 10 Difficult 1 3.5X10 ” ⁶ 95 5.0X10 ² 30

5.1X10— ⁶ 90 1.0X10 ³ 15

Difficult 3 8.2X10 1 ⁶ 92 1.1X10 ³ 40

^{■ 14 6 · 7Χ1 (Γ 6} 92 1. OX 10 3 30 discussions 15 4.5X10- ⁶ 94 1.2X10 ³ 40謹3.2X10 one ⁶ 94 1. OX 10 ³ 40赚^{7 3 · 7X10- 6 94 1. O} 10 ³ 40 Shelf 18 3.2X10 1 ⁶ 93 1.9X10 ³ 30 Difficult 9 3.5X1CT ⁶ 94 1.8X10 ³ 30 Translate 20 3.6X10 " ⁶ 94 2. OX10 ³ 20 Actual, 1 3.4X10 1 ⁶ 92 2.0X10 ³ 15 Translate 4 2.5 X10- ⁶ 94 1. oxio ² 110 table 3 as is apparent from the composition and the conductive coating film formed using the embodiments 10 to 21, conductive coating formed by using the composition of Comparative example 4 Compared to the film, the specific resistance and reflectance were comparable, but the average surface roughness of the coating film was llOnm in Comparative Example 4, whereas Examples 10-21 were in the range of 10-40 nm. It was confirmed that the surface roughness in a range suitable for the texture structure of the back electrode constituting the substrate type solar cell was obtained.

 <Examples 22 to 58, Comparative Examples 5 to 8>

First, metal salts of the type forming metal nanoparticles shown in Tables 4 to 6 below were dissolved in deionized water to prepare an aqueous metal salt solution. The concentration was prepared Kuen aqueous solution of sodium 26 weight _^0/0 by dissolving sodium Kuen acid in deionized water. In this aqueous sodium citrate solution, granular ferrous sulfate is directly added and dissolved in a nitrogen gas stream maintained at 35 ° C, and the citrate ion and ferrous ion are mixed at a molar ratio of 3: 2. An aqueous reducing agent solution was prepared.

[0124] Next, with the nitrogen gas stream maintained at 35 ° C, the magnetic stirrer stirrer was placed in the reducing agent aqueous solution, and the stirrer was rotated at a rotation speed of lOOrpm, While stirring the reducing agent aqueous solution, the metal salt aqueous solution was added dropwise to the reducing agent aqueous solution and mixed. Here, the metal salt aqueous solution at room temperature was dropped by adjusting the concentration of each solution so that the amount of the metal salt aqueous solution added to the reducing agent aqueous solution was 1/10 or less of the amount of the reducing agent aqueous solution. The reaction temperature was kept at 40 ° C. The mixing ratio of the reducing agent aqueous solution to the metal salt aqueous solution is 3 times the molar ratio of the citrate ion and ferrous ion in the reducing agent aqueous solution to the total valence of the metal ions in the metal salt aqueous solution. It was made to be a mole. After the addition of the aqueous metal salt solution to the reducing agent aqueous solution is completed, stirring of the mixed solution is further continued for 15 minutes to generate metal particles inside the mixed solution, thereby obtaining a metal particle dispersion liquid in which the metal particles are dispersed. It was. The pH of the metal particle dispersion was 5.5, and the stoichiometric amount of metal particles in the dispersion was 5 g / liter.

 [0125] The obtained dispersion was allowed to stand at room temperature, whereby the metal particles in the dispersion were allowed to settle, and aggregates of the precipitated metal particles were separated by decantation. Deionized water was added to the separated metal agglomerate to form a dispersion, which was desalted by ultrafiltration, and further washed by displacement with methanol to make the metal content 50% by mass. Then, using a centrifuge, the centrifugal force of the centrifuge is adjusted to separate relatively large metal particles with a particle size exceeding lOOnm. Was adjusted to contain 71% in number average. That is, the proportion of metal nanoparticles in the primary particle size range of 10 to 50 nm with respect to 100% of all metal nanoparticles was adjusted to 71% on a number average. The resulting metal nanoparticles were chemically modified with a protective agent for an organic molecular main chain having a carbon skeleton of 3 carbon atoms.

 [0126] Next, 10 parts by weight of the obtained metal nanoparticles were added and dispersed in 90 parts by weight of a mixed solution containing water, ethanol and methanol. Furthermore, by adding the additives shown in the following Table 4 to Table 6 to this dispersion so as to have the ratios shown in Table 4 to Table 6, compositions for application tests of Examples 22 to 58 and Comparative Examples 5 to 8 Respectively.

 [0127] <Comparison test 3>

Various coating test compositions obtained in Examples 22 to 58 and Comparative Examples 5 to 8 were formed on the substrates shown in Tables 4 to 6 so as to have a film thickness of 10 ² to ² × 10 ³ nm. After coating with a suitable film formation method, the conductive coating film is formed on the substrate by baking under the heat treatment conditions shown in Table 4 to Table 6 below. Formed.

 [0128] With respect to the formed conductive coating film, adhesion to the substrate, specific resistance, reflectance, coating film thickness and average surface roughness were determined. The adhesion to the substrate was evaluated by a method based on JIS K 5600-5-6 (cross-cut method) and evaluated qualitatively. Specifically, when no significant peeling occurred in the coating film, that is, when the peeling classification was in the range of 0 to 2, it was evaluated as “good”, and the others were evaluated as “bad”. The specific resistance of the coating film was calculated by measuring the surface resistance of the coating film by the four-probe method, measuring the film thickness of the coating film by SEM, and calculating from the measured surface resistance and film thickness. The reflectance of the coating film was evaluated by measuring the diffuse reflectance of the coating film at a wavelength of 800 nm using a combination of an ultraviolet-visible spectrophotometer and an integrating sphere. The coating thickness was measured by cross-sectional observation with SEM. The average surface roughness was obtained by evaluating the evaluation value for the surface shape obtained by AFM according to JIS B0601. The results are shown in Table 7 and Table 8, respectively.

[0129] [Table 4]

Five]

[9 挲] [τετο]

0S.690 / Z.00idf / X3d 9 讓 00Z OAV Heat treatment Gold crab / Particles Additives Film formation method Base material

 Temperature [in] Time [min] Atmosphere 删 49 Ag

 Co b 95 | ί¾ PVP (MW360000) 4 mass ¾ Spin coating Pomit '320 20 Atmosphere

 Cum 1 mass ¾

娜 0 Ag 95. 9 quality ^ PVP (MW360000) 4 || ¾ Spin coating Boi 5 '320 20 Danu, manganese 0.1 mass ¾

Difficult 1 Ag 95. 9 mass ¾ PVP (W360000) 4 mass% Spin coating Po'Mito '320 20 Large'

 0.1% by mass

Actual paste 52 Ag 95. 9 mass ¾ PVP (MW 360000) 4 mass ¾ Spin coating Polyimito '320 20 Large cobalt formate 0.1 mass ¾

娜 3 Ag 95g |% PVA (W 16000) 4ΪΙ% Spin coating Poly 320 20 Large

 Nickel 1 mass ¾

In fact, Ag 9511% PVP (W360000) 4 mass ¾ ¾e. Spin coating polyimito '320 20 atmosphere

 Quan 1 mass ¾

Shelf 55 Ag 95fl¾ Spin coating Polyimito '320 20 ₂ 6 Ag 95 Mass Spin coating Polyimito' 320 20 Atmosphere Actual 57 Ag 95 Mass¾ PVA (MW 16000) 4 Mass ¾ Spin coating Polyimito '320 20 Large ft ft 1 mass ¾

 Ag 95 mass PVA (W 16000) 4 Poor amount ¾ Subcoating polyimide 320 20 Atmosphere m 1 mass ¾

删 5 Ag 100 mass ¾ None Spray coating pomito '200 20 Atmosphere Reference 6 None Spray coating IT0 200 20 Atmosphere fine / Ag 95 quality t¾ None Dispenser PET 130 20 N, Cu 5li¾ Coating

顏 8 Ag 99. 8 Mass ¾ None Su--Polymit '320 20 Atmosphere Mn 0.2 Mass ¾ 7]

Adhesiveness Specific resistance [Ω · cm] Reflectivity (800nm) [% R] Coating thickness [nm] Average surface roughness [nm] Actual 2 Good 3.1X10— ⁶ 95 1.0X10 ² 10 Shelf 23 Good 3.5X10 1 ⁶ 95 5. OX 10 ² 30 Glue 24 Good 5. IX 10— ⁶ 90 1. OX 10 ³ 15 Fine 25 Good 8.2X 10— ⁶ 92 1.1X10 ³ 40 Measurement 26 Good 6.7X10— ⁶ 92 1.0X10 ³ 30誦27 good 4.5X10- ⁶ 94 1.2X 10 ³ 40 flame 8 good 3.2X10 one ⁶ 94 1.0 × 10 ³ 40 transliteration 29 good 3.7X10- ⁶ 94 1.0X10 ³ 40 real 0 good 3.2X 10- ⁶ 93 1.9X 10 ³ 30 Shelf 31 Good 3. δΧΙΟ— ¹ * 94 1.8X10 ³ 30 赚 2 Good 3.6X10 ¹⁶ 94 2.0X10 ³ 20 瞧 3 Good 3.4 × 10 1 ⁶ 92 2. OX 10 ³ 15 纖 34 Good 2.1X10— ⁶ 88 2.0X10 ³ 90

■ 35 Good 2.5X10 1 ⁶ 86 1.9X 10 ³ 100 Thin 36 Good 4.2X 10— ⁶ 83 1. OX 10 ³ 70 Real Good 4. ΙΧΙΟ ^-6 85 1.1X10 ³ 90 Real 8 Good 3.9X10 1 ⁶ 88 1. OX 10 ³ 80 赚 9 Good 5.2X 10 1 ⁶ 82 1.2X 10 ³ 90 Actual Good 3.2X10— ⁶ 94 1.2X 10 ³ 30 8]

Adhesiveness Specific resistance [Ω · η] Reflectance (800tim) [R] Coating thickness [nm] Average surface roughness [nm] Difficult 1 Good 5.5X10 " ⁶ 80 LOX10 ³ 50

Good 4.9X10 1 ⁶ 85 1.0X10 ³ 60

Good 5.2X10 " ⁶ 81 1. O 10 ³ 50

Real, Good 4.9X10— ⁶ 82 1.0X 10 ³ 70

Thin 45 Good 4.8X10— ⁶ 85 1.1 X 10 ³ 80

Good glue 5.1X10— ⁶ 84 1. OX 10 ³ 70

Tone Good 3.5X10— ⁶ 85 1.1X10 ³ 60

48 good 3.2X10 "° 82 1. OX 10 ³ 60

Difficult 9 Good 3.3Χ 10— ⁶ 80 1.1X10 ³ 70

Real Good 3.7X10 1 ⁶ 88 1. OX 10 ³ 70

誦 51 Good 3.2Χ 10 " ⁶ 90 1. OX 10 ³ 50

Good 2.5X10 " ⁶ 91 1.2X 10 ³ 30

Transform 53 Good 4. IX 10 1 ⁶ 86 1. IX 10 ³ 50

Real, Good 3.7X10— ⁶ 88 1. OX 10 ³ 40

Good 4.5X10 1 ⁶ 85 l.OX 10 ³ 60

56 56 Good 3.4X10 1 ⁶ 82 1. OX 10 ³ 50

赚 7 Good 3.2X10— ⁶ 83 1. IX 10 ³ 70

纖 58 Good 4.2Χ 10 " ⁶ 84 1. OX 10 ³ 50

Class 5 Defect 2.5X10- ⁰ 94 1.0X10 ³ 110

Fine 6 Defect 4.9X10 ⁶ 89 1.0X10 ³ 105

Specific glue 7 Defect 4.3Χ 10 " ⁶ 92 1.2 10 ³ 110

Class 8 Defect 3.2X10 1 ⁶ 89 2. OX 10 ³ 110 As is clear from Table 8, in Comparative Examples 5 to 8 where no additive was added to the composition, the adhesion to the base material was `` Poor ''. The result was inferior in adhesion. On the other hand, as is clear from Tables 7 and 8, the conductive coating films formed using the compositions of Examples 22 to 58 had good adhesion to the substrate. Further, in Examples 22 to 58, specific resistance close to the specific resistance of the metal itself constituting the metal nanoparticles contained in the composition was obtained, and the coating film formed using the composition of the present invention. Was confirmed to have high conductivity. In addition, an excellent reflectance close to the reflectance of the metal itself constituting the metal nanoparticles contained in the composition is obtained. It was found that the reflectance does not decrease even when an additive is added. Furthermore, it can be confirmed that the average surface roughness of the coating film is within the range of 10 to 100 nm, and the surface roughness is in a range suitable for the texture structure of the back electrode constituting the substrate type solar cell. It was. Industrial applicability

 According to the present invention, an electrode forming composition, a method of forming an electrode using this composition, a solar cell electrode, an electronic paper electrode, a solar cell, and an electronic paper obtained by the above method can be provided. It is extremely useful in industry.

Claims

The scope of the claims

 [1] An electrode-forming composition in which metal nanoparticles are dispersed in a dispersion medium,

 The composition contains one or more organic polymers selected from the group consisting of polybulurpyrrolidone, polybulurpyrrolidone copolymer, polybulal alcohol and cellulose ether.

 A composition for forming an electrode.

[2] The composition for electrode formation according to [1], wherein the content of the organic polymer is from 0.;

 [3] The composition for electrode formation according to [1], wherein the metal nanoparticles contain 75% by mass or more of silver nanoparticles.

 [4] The composition for electrode formation according to claim 1, wherein the metal nanoparticles are chemically modified with a protective agent for an organic molecular main chain having a carbon skeleton of 1 to 3 carbon atoms!

5. The electrode forming composition according to claim 1, wherein the metal nanoparticles contain a metal nanoparticle having a primary particle size in the range of 10 to 50 nm in a number average of 70% or more.

[6] Metal nanoparticles containing 75% by mass or more of silver nanoparticles, and gold, platinum, palladium

Further comprising one particle selected from the group consisting of ruthenium, nickel, copper, tin, indium, zinc, iron, chromium, and manganese, or a particle composed of two or more mixed compositions or alloy compositions,

 2. The electrode forming composition according to claim 1, wherein the content of particles other than silver nanoparticles contained in the metal nanoparticles is 0.02 mass% or more and less than 25 mass%.

7. The electrode forming composition according to claim 1, wherein the dispersion medium is an alcohol or an alcohol-containing aqueous solution.

 8. The electrode forming composition according to claim 1, further comprising one or more additives selected from the group consisting of metal oxides, metal hydroxides, organometallic compounds, and silicone oils.

Yes

[9] Oxidation in which the metal oxide includes at least one selected from the group consisting of aluminum, silicon, titanium, chromium, manganese, iron, cobalt, nickelol, silver, copper, zinc, molybdenum, tin, indium, and antimony 9. The electrode forming assembly according to claim 8, wherein the electrode forming assembly is an oxide or a complex oxide Adult.

 [10] The metal hydroxide contains at least one selected from the group consisting of aluminum, silicon, titanium, chromium, manganese, iron, cobalt, nickel, silver, copper, zinc, molybdenum, tin, indium and antimony 9. The electrode forming composition according to claim 8, which is a hydroxide.

[11] The electrode formation according to claim 8, wherein the organometallic compound is a metal sarcophagus, metal complex or metal alkoxide of silicon, titanium, chromium, manganese, iron, cobalt, nickel, silver, copper, zinc, molybdenum and tin. Composition.

[12] A process of coating the electrode-forming composition according to claim 1 on a substrate by a wet coating method to form a film;

 Firing the substrate formed on the upper surface at 130 to 400 ° C;

 A method for forming an electrode comprising:

13. The method for forming an electrode according to claim 12, wherein the thickness of the electrode after firing formed on the upper surface of the substrate is in the range of 0 .;! To 2.0 m.

[14] The average surface roughness of the electrode formed on the upper surface of the substrate is in the range of 10 to;! OOnm.

2. The method for forming an electrode according to 2.

[15] The substrate is made of silicon, glass, ceramics including a transparent conductive material, a substrate made of a polymer material or metal, or the silicon, glass, ceramics including the transparent conductive material, or the polymer material 13. The method for forming an electrode according to claim 12, wherein the electrode is a laminate of two or more selected from the group consisting of the metals.

[16] The base material is either a solar cell element or a solar cell element with a transparent electrode.

2. The method for forming an electrode according to 2.

[17] The wet coating method is one of the spray coating method, the dispenser coating method, the spin coating method, the knife coating method, the slit coating method, the ink jet coating method, the screen printing method, the offset printing method or the die coating method. Claim

12. A method for forming an electrode according to 12.

18. A solar cell electrode obtained by the forming method according to claim 12.

[19] An electrode for electronic paper obtained by the forming method according to claim 12.

[20] At least composed of a substrate, a back electrode, a photoelectric conversion layer, and a transparent electrode, 19. The solar cell electrode according to claim 18, which is a back electrode of a solar cell having a substrate structure formed in the order of the substrate, the back electrode, the photoelectric conversion layer, and the transparent electrode.

 [21] at least composed of a substrate, a transparent electrode, a photoelectric conversion layer and a back electrode,

 19. The solar cell electrode according to claim 18, which is a back electrode of a solar cell having a superstrate structure formed in the order of the substrate, the transparent electrode, the photoelectric conversion layer, and the back electrode.

 22. A solar cell comprising the solar cell electrode according to claim 18.

 23. An electronic paper comprising the electronic paper electrode according to claim 19.