JP5326647B2 - Method for producing composition for forming electrode of solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition for forming an electrode for solar cell, which can provide an electrode excellent in aging stability, the electrode capable of maintain high conductivity and high reflectance even after a long time use. <P>SOLUTION: The composition for forming an electrode for solar cell is configured by dispersing metal nanoparticles in a dispersion medium. The metal nanoparticles contain not less than 75 mass% silver nanoparticles. The metal nanoparticles are chemically modified with a protective agent whose carbon skeleton comprises an organic molecule principal chain having 1-3 carbons. Further, the metal nanoparticles contain metal nanoparticles having a primary particle diameter in a range of 10-50 nm, in a proportion of not less than 70% by number on the average. The dispersion medium is any one of 1,2-propanediol, ethylene glycol, dimethylsulfoxide, and N-methyl formamide. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention relates to a manufacturing method of the composition for forming an electrode of a solar cell.

  Conventionally, as a method for forming this type of electrode, a solution obtained by dispersing ultrafine metal particles having a particle size of 0.03 μm or less in an organic solvent having a low molecular weight of about 100 to 200 is applied to a photoelectric conversion semiconductor layer and fired. A lower electrode layer is formed, and a solution having a concentration of the ultrafine metal particles equal to or higher than that used for forming the lower electrode layer is applied to the photoelectric conversion semiconductor layer. A method for forming a metal electrode of a solar cell that forms an upper electrode layer by firing is disclosed (for example, see Patent Document 1). In this metal electrode forming method, a solution in which ultrafine metal particles are dispersed and the viscosity is adjusted to about 10,000 cps is applied to the photoelectric conversion semiconductor layer by a screen printing method or the like, and then the temperature is set to 100 to 250 ° C., preferably 250 ° C. A metal electrode (lower electrode layer or upper electrode layer) is formed by holding and baking for at least a minute.

  In the method for forming a metal electrode of a solar cell configured in this way, after applying a solution in which metal ultrafine particles are dispersed in an organic solvent to a photoelectric conversion semiconductor layer, sintering is performed at a low temperature of 100 to 250 ° C. Without using a vacuum process, a metal electrode having a high reflectance and conductivity and a large area can be obtained.

Japanese Patent No. 3287754 (claim 1, paragraph [0024], paragraph [0035])

  In the conventional method for forming a metal electrode of a solar cell shown in Patent Document 1, in order to stabilize the metal ultrafine particles in the fired metal electrode, the metal ultrafine particles are added in an amount of 100 to 100 while ensuring predetermined conductivity. It is necessary to protect with an organic substance having a low molecular weight of about 200. On the other hand, if the size of the metal ultrafine particles is reduced in order to sinter the metal ultrafine particles dispersed in the organic solvent at a low temperature, the specific surface area of the metal ultrafine particles increases and the proportion of the organic matter increases. For this reason, in the conventional metal electrode forming method for solar cells shown in Patent Document 1, low-temperature sintering of metal ultrafine particles dispersed in an organic solvent is performed by desorbing or decomposing (separating) the organic matter by heat. If the weather resistance test is performed on a metal electrode obtained by firing metal ultrafine particles dispersed in an organic solvent at 220 ° C. or lower, specifically, the temperature is set to 100 ° C. When the metal electrode is housed in a constant temperature and humidity chamber maintained at 50% and humidity of 50% for 1000 hours, the organic matter is altered or deteriorated, resulting in a decrease in conductivity and reflectance.

An object of the present invention, even when used for many years can maintain a high conductivity and a high reflectance, it is possible to obtain an excellent electrode aging stability, a manufacturing method of an electrode forming composition for a solar cell It is to provide.

  In the composition described in the first aspect of the present invention, since the metal nanoparticle having a primary particle size of 10 to 50 nm and a relatively large size is contained in a large amount, the specific surface area of the metal nanoparticle is reduced, and the protective agent occupies it. When the composition of the composition is used to form a solar cell electrode, the protective agent is desorbed or decomposed by heat during firing, or is separated and decomposed to substantially contain organic matter. An electrode mainly composed of silver is obtained.

The first aspect of the present invention is to prepare a reducing agent aqueous solution by dissolving by adding concentration 10-40% of granular or powdery ferrous sulfate aqueous sodium citrate solution in a stream of inert gas Adding a silver nitrate aqueous solution to the reducing agent aqueous solution while stirring the reducing agent aqueous solution in an inert gas stream so that the addition amount of the silver nitrate aqueous solution is 1/10 or less of the amount of the reducing agent aqueous solution. Mixing the mixture, stirring the mixture for 10 to 300 minutes to prepare a dispersion made of metal colloid, and allowing the dispersion made of metal colloid to stand at room temperature to precipitate the precipitated metal nanoparticles. A step of separating the aggregate from the dispersion, a step of adding water to the separation to form a dispersion, and separating coarse particles obtained by desalting the dispersion by ultrafiltration Particle size 10-50 a step of obtaining a metal nanoparticle dispersion containing 70% or more of metal nanoparticles within the range of m in number average, and the metal nanoparticle dispersion of 1,2-propanediol, dimethyl sulfoxide or N-methylformamide. look including the step of obtaining an electrode-forming composition of the solar cell was replaced washed with either aqueous sodium the citrate are those obtained by dissolving sodium citrate in deionized water, the metal nano Particles are dispersed in a dispersion medium, silver nanoparticles having 75% by weight or more of metal nanoparticles, and Au, Pt, Pd, Ru, Ni, Cu, Sn, In, Zn having 0.02% by weight or more and less than 25% by weight. , Fe, Cr, or Mn nanoparticles, the metal nanoparticles are chemically modified with a protective agent of an organic molecular main chain having 1 to 3 carbon atoms in the carbon skeleton, and the metal nanoparticles have a primary particle size of 10 to 50 nm. The number of metal nanoparticles in the range is 70% or more on average, the dispersion medium is any of 1,2-propanediol, dimethyl sulfoxide, or N-methylformamide, and the metal content is 2.5 to 95 mass. % Of the composition for forming a solar cell electrode.

As described above, according to the present invention, the metal nanoparticles dispersed in the dispersion medium contain 75% by mass or more of silver nanoparticles, and the protective agent for the organic molecular main chain having a carbon skeleton of 1 to 3 carbon atoms. in metal nanoparticles is chemically modified, contain further 70% or more by number average metal nanoparticles within the metal nanoparticle primary particle size 10 to 50 nm, further dispersion medium 1,2-propanediol, di-methyl Since it is either sulfoxide or N-methylformamide, the specific surface area of the metal nanoparticles in this composition is relatively reduced, and the proportion of the protective agent is reduced. As a result, when an electrode of a solar cell is formed using this composition, the organic molecules in the dispersion medium are desorbed or decomposed by the heat at the time of firing, or are separated and decomposed to substantially remove the organic matter. An electrode composed mainly of silver not containing is obtained. Therefore, even if the solar cell on which the electrode is formed is used for many years, the organic matter is not deteriorated or deteriorated, and the electrical conductivity and the reflectance are maintained in a high state. Can be obtained.

  In addition, the electrode forming composition is applied onto a substrate by a wet coating method, and a film is formed so that the thickness after firing is within a range of 0.1 to 2.0 μm, and the film is formed on this upper surface. If the base material is baked at 130 to 400 ° C., the protective agent that protected the surface of the metal nanoparticles was detached or decomposed, or separated and decomposed, so that substantially no organic matter-containing silver was obtained. An electrode having the main component is obtained. As a result, similarly to the above, even if the solar cell on which the electrode is formed is used for many years, the conductivity and the reflectance are maintained at a high level, so that an electrode having excellent aging stability can be obtained.

  Next, the form for implementing this invention is demonstrated.

  The composition of the present invention is a composition for forming an electrode of a solar cell in which metal nanoparticles are dispersed in a dispersion medium. The metal nanoparticles contain 75% by mass or more, preferably 80% by mass or more of silver nanoparticles. The metal nanoparticles are chemically modified with a protective agent having an organic molecular main chain having a carbon skeleton of 1 to 3 carbon atoms. Further, the metal nanoparticles contain 70% or more, preferably 75% or more of metal nanoparticles having a primary particle size in the range of 10 to 50 nm in terms of number average. Here, the content of silver nanoparticles was limited to a range of 75% by mass or more with respect to 100% by mass of all metal nanoparticles, and less than 75% by mass of solar cells formed using this composition. This is because the reflectance of the electrode is lowered. Moreover, the carbon number of the carbon skeleton of the organic molecular main chain of the protective agent for chemically modifying the metal nanoparticles was limited to the range of 1 to 3 because the protective agent was removed by the heat during firing if the carbon number was 4 or more. This is because separation or decomposition (separation / combustion) is difficult, and a large amount of organic residue remains in the electrode, resulting in alteration or deterioration, resulting in a decrease in the conductivity and reflectance of the electrode. In addition, the content of the metal nanoparticles in the range of the primary particle size of 10 to 50 nm is limited to the range of 70% or more with respect to 100% of all the metal nanoparticles on the number average. Since the specific surface area of the particles increases and the proportion of the protective agent increases, even in the case of organic molecules that are easily desorbed or decomposed (separated / combusted) by the heat during firing, the organic molecules account for a large proportion. Many organic residues remain, and the residue is altered or deteriorated to reduce the conductivity and reflectivity of the electrode, or the particle size distribution of the metal nanoparticles becomes wide and the electrode density tends to decrease. This is because the properties and reflectivity are reduced. Furthermore, the primary particle size of the metal nanoparticles was limited to the range of 10 to 50 nm because the metal nanoparticles having a primary particle size within the range of 10 to 50 nm are stable over time (statistical stability). It is because it correlates.

On the other hand, the content of the metal nanoparticles including silver nanoparticles is 2.5 to 95.0% by mass, preferably 3.5 to 90.0% with respect to 100% by mass of the composition comprising the metal nanoparticles and the dispersion medium. Contains by mass%. The dispersion medium is 1,2-propanediol is either di-methyl sulfoxide or N- methyl formamide. Here, the content of the metal nanoparticles including the silver nanoparticles was limited to the range of 2.5 to 95.0% by mass with respect to 100% by mass of the composition composed of the metal nanoparticles and the dispersion medium. If it is less than 5% by mass, the properties of the electrode after firing are not particularly affected, but it is difficult to obtain an electrode having a required thickness. If it exceeds 95.0% by mass, it can be used as an ink or paste during wet coating of the composition. This is because the necessary liquidity is lost. The reason for limiting the dispersion medium to 1,2-propanediol , dimethyl sulfoxide or N-methylformamide is that when these dispersion media are used, the metal nanoparticles do not aggregate for a long period of time and are stable. This is because the film obtained by coating by the coating method can be sintered at a low temperature, and the conductivity and reflectance of the electrode after firing are good.

  On the other hand, the metal nanoparticles other than silver nanoparticles are one or a mixture of two or more selected from the group consisting of Au, Pt, Pd, Ru, Ni, Cu, Sn, In, Zn, Cr, Fe and Mn. It is a metal nanoparticle which consists of a composition or an alloy composition, and metal nanoparticles other than this silver nanoparticle are 0.02 mass% or more and less than 25 mass% with respect to 100 mass% of all metal nanoparticles, Preferably it is 0.03. It is contained in an amount of 20% to 20% by mass. Here, the content of metal nanoparticles other than silver nanoparticles is limited to 0.02% by mass or more and less than 25% by mass with respect to 100% by mass of all metal nanoparticles. However, in the range of 0.02 to 25% by mass, the conductivity of the electrode after a 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). And 25% by mass or more, the conductivity and reflectance of the electrode immediately after firing are reduced, and the electrode after the weathering test is the electrode before the weathering test. This is because the conductivity and reflectance are further reduced.

  The manufacturing method of the composition for electrode formation of the solar cell comprised in this way is demonstrated.

(a) When the carbon number of the carbon skeleton of the organic molecular main chain of the protective agent for chemically modifying the silver nanoparticles is set to 3 First, silver nitrate is dissolved in water such as deionized water to prepare an aqueous metal salt solution. On the other hand, the aqueous solution of sodium citrate having a concentration of 10 to 40% obtained by dissolving sodium citrate in deionized water or the like is mixed with granular or powdered sulfuric acid in a stream of inert gas such as nitrogen gas. Iron is directly added and dissolved to prepare an aqueous reducing agent solution containing citrate ions and ferrous ions in a molar ratio of 3: 2. Next, the aqueous metal salt solution is added dropwise to and mixed with the reducing agent aqueous solution while stirring the reducing agent aqueous solution in the inert gas stream. Here, by adjusting the concentration of each solution so that the addition amount of the metal salt aqueous solution is 1/10 or less of the amount of the reducing agent aqueous solution, the reaction temperature is 30 to 30 even when the metal salt aqueous solution at room temperature is dropped. It is preferable to keep the temperature at 60 ° C. The mixing ratio of the two aqueous solutions is such that the molar ratio of the citrate ions and the ferrous ions in the reducing agent aqueous solution is 3 times the total valence of the metal ions in the metal salt aqueous solution. . After the dropping of the aqueous metal salt solution is completed, the mixture is further stirred for 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, etc., and then water such as deionized water is added to the separation to form a dispersion, followed by ultrafiltration. After that, the metal nanoparticles having a primary particle diameter of 10 to 50 nm are obtained by adjusting the centrifugal force of the centrifuge using a centrifuge and separating coarse particles. Prepare so as to contain 70% or more in number average, that is, adjust the proportion of metal nanoparticles in the range of primary particle size of 10 to 50 nm to 100% of all metal nanoparticles in number average to be 70% or more. To do. Although described as metal nanoparticles, in the case of (a), the proportion of silver nanoparticles in the range of the primary particle size of 10 to 50 nm with respect to 100% of all silver nanoparticles is 70% or more. It is adjusted so that Subsequent to substitution washing with either 1,2-propanediol , dimethyl sulfoxide or N-methylformamide, the metal (silver) content is adjusted to 2.5 to 50% by mass.

  In the number average measurement method, first, the obtained metal nanoparticles are photographed with a TEM (Transmission Electron Microscope) at a magnification of about 500,000 times. Next, a primary particle size is measured for 200 metal nanoparticles from the obtained image, and a particle size distribution is created based on the measurement result. Next, from the created particle size distribution, the ratio of the number of metal nanoparticles within the range of the primary particle size of 10 to 50 nm occupied by all metal nanoparticles is determined.

As a result, a dispersion (a composition for forming an electrode of a solar cell) in which the carbon skeleton of the carbon skeleton of the organic molecular main chain of the protective agent that chemically modifies the silver nanoparticles is obtained. The final metal content (silver content) with respect to 100% by mass of the dispersion is 2.5 to 95% by mass, and the solvent is any of 1,2-propanediol , dimethyl sulfoxide, or N-methylformamide. Use.

(b) When the carbon number of the carbon skeleton of the organic molecular main chain of the protective agent that chemically modifies the silver nanoparticles is set to 2 except that sodium citrate used when preparing the reducing agent aqueous solution is replaced with sodium malate A dispersion is prepared in the same manner as (a) above. As a result, a dispersion (a composition for forming an electrode for a solar cell) in which the carbon skeleton of the organic molecular main chain that chemically modifies the silver nanoparticles is 2 is obtained.

(c) When the carbon number of the carbon skeleton of the organic molecular main chain of the protective agent for chemically modifying the silver nanoparticles is 1, except that sodium citrate used when preparing the reducing agent aqueous solution is replaced with sodium glycolate A dispersion is prepared in the same manner as in the above (a). Thereby, a dispersion (composition for forming an electrode of a solar cell) in which the carbon skeleton of the organic molecular main chain that chemically modifies the silver nanoparticles has 1 is obtained.

(d) When the number of carbon atoms in the carbon skeleton of the organic molecular main chain of the protective agent for chemically modifying metal nanoparticles other than silver nanoparticles is 3, the metal constituting the metal nanoparticles other than silver nanoparticles is Au, Pt, Pd, Ru, Ni, Cu, Sn, In, Zn, Fe, Cr, or Mn may be mentioned. The silver nitrate used to prepare the aqueous metal salt solution is chloroauric acid, chloroplatinic acid, palladium nitrate, ruthenium trichloride, nickel chloride, cuprous nitrate, tin dichloride, indium nitrate, zinc chloride, iron sulfate, sulfuric acid A dispersion is prepared in the same manner as in the above (a) except that it is replaced with chromium or manganese sulfate. As a result, a dispersion (a composition for forming an electrode for a solar cell) in which the carbon skeleton of the organic molecular main chain of the protective agent for chemically modifying metal nanoparticles other than silver nanoparticles is 3 is obtained.

  In addition, when the carbon number 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 1 or 2, the silver nitrate used when preparing the metal salt aqueous solution is the above kind. A dispersion is prepared in the same manner as in the above (b) and (c) except that the metal salt is replaced. Thereby, the dispersion (composition for electrode formation of a solar cell) whose carbon number of the carbon skeleton of the organic molecular principal chain of the protective agent which chemically modifies metal nanoparticles other than silver nanoparticles is 1 or 2 is obtained.

  When metal nanoparticles other than silver nanoparticles are contained together with silver nanoparticles as metal nanoparticles, a dispersion containing silver nanoparticles produced by the method of (a) is used as the first dispersion, and ( When the dispersion containing metal nanoparticles other than silver nanoparticles produced by the method of d) is defined as the second dispersion, the first dispersion of 75% by mass or more and the second dispersion of less than 25% by mass are the first. And it mixes so that the total content of a 2nd dispersion may be 100 mass%. 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). You may use the dispersion containing the silver nanoparticle manufactured by the method.

  A method for forming an electrode using the dispersion (a composition for forming an electrode of a solar cell) thus manufactured will be described.

First, the dispersion (a composition for forming an electrode of a solar cell) is coated on a substrate by a wet coating method. Coating by this wet coating method is performed so that the thickness after firing is in the range of 0.1 to 2.0 μm, preferably 0.3 to 1.5 μm. The substrate is selected from the group consisting of silicon, glass, ceramics containing a transparent conductive material, a polymer material or a metal substrate, or silicon, glass, ceramics containing a transparent conductive material, a polymer material and a metal. It can be a laminate of two or more types. Moreover, it is preferable that a base material is either a solar cell element or a solar cell element with a transparent electrode. Transparent electrodes include indium tin oxide (ITO), antimony-doped tin oxide (ATO), nesa (tin oxide SnO ₂ ), IZO (Indium Zic Oxide), and AZO (aluminum-doped ZnO). Etc. The said dispersion is apply | coated to the surface of the photoelectric conversion semiconductor layer of a solar cell element, or the surface of the transparent electrode of a solar cell element with a transparent electrode. Further, the wet coating method is particularly a spray coating method, a dispenser coating method, a spin coating method, a knife coating method, a slit coating method, an ink jet coating method, a screen printing method, an offset printing method or a die coating method. Although it is preferable, the present invention is not limited to this, and any method can be used. The spray coating method is a method in which the dispersion is atomized by 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 the dispersion is injected into a syringe. The dispersion is discharged from the fine nozzle at the tip of the syringe and applied to the substrate by pushing the piston of the syringe. The spin coating method is a method in which a dispersion is dropped onto a rotating substrate, and the dropped dispersion is spread to the periphery of the substrate by its centrifugal force. The knife coating method leaves a predetermined gap from the tip of the knife. In this method, the substrate is provided so as to be movable in the horizontal direction, the dispersion is supplied onto the substrate upstream of the knife, and the substrate is moved horizontally toward the downstream side. The slit coating method is a method in which a dispersion is discharged from a narrow slit and applied onto a substrate, and the inkjet coating method is a method in which a dispersion is filled in an ink cartridge of a commercially available inkjet printer and ink jet printing is performed on the substrate. is there. The screen printing method is a method in which wrinkles are used as a pattern indicating material and a dispersion is transferred to a substrate through a plate image formed thereon. The offset printing method is a printing method utilizing 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. . The die coating method is a method in which a dispersion supplied in a die is distributed by a manifold and extruded onto a thin film from a slit to coat the surface of a traveling substrate. The die coating method includes a slot coat method, a slide coat method, and a curtain coat method.

  Next, the base material formed on the upper surface is fired in the air at a temperature of 130 to 400 ° C., preferably 140 to 200 ° C., for 10 minutes to 1 hour, preferably 15 to 40 minutes. Here, the film thickness of the dispersion formed on the substrate was limited so that the thickness after firing was in the range of 0.1 to 2.0 μm. This is because the necessary surface resistance value of the electrode becomes insufficient, and if it exceeds 2.0 μm, there is no problem in characteristics, but the amount of material used is increased more than necessary and the material is wasted. In addition, the firing temperature of the dispersion film formed on the base material was limited to the range of 130 to 400 ° C. When the temperature was lower than 130 ° C., the sintering between the metal nanoparticles became insufficient and the protective agent was fired. It is difficult to desorb or decompose (separate / combust) due to the heat of heat, so that a lot of organic residue remains in the electrode after firing, and this residue is altered or deteriorated, resulting in a decrease in conductivity and reflectance. This is because the production advantage of the low-temperature process cannot be utilized, that is, the manufacturing cost increases and the productivity decreases. Furthermore, the firing time of the dispersion film formed on the base material was limited to the range of 10 minutes to 1 hour because the sintering of the metal nanoparticles became insufficient and the firing of the protective agent in less than 10 minutes. Due to the difficulty of desorption or decomposition (separation / combustion) due to the heat of the time, a lot of organic residue remains in the electrode after firing, the residue is altered or deteriorated, and the conductivity and reflectivity of the electrode decrease, This is because, if the time exceeds 1 hour, the characteristics are not affected, but the manufacturing cost is increased more than necessary and the productivity is lowered.

Since the composition for forming an electrode of the solar cell contains 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 of a solar cell is formed using the composition, the organic molecules in the protective agent are desorbed or decomposed by the heat at the time of firing, or desorbed and decomposed, thereby substantially reducing the organic matter. An electrode composed mainly of silver not containing is obtained. Therefore, even if the solar cell on which the electrode is formed is used for many years, the organic matter is not deteriorated or deteriorated, and the conductivity and reflectivity of the electrode are maintained in a high state, so that the aging stability is excellent. An electrode can be obtained. Specifically, even after the electrode is accommodated for 1000 hours in a constant temperature and humidity chamber maintained at a temperature of 100 ° C. and a humidity of 50%, the electromagnetic wave having a wavelength of 750 to 1500 nm, that is, from the visible light region. Electromagnetic waves up to the infrared region can be reflected by 80% or more by the electrode, and the conductivity of the electrode, that is, the volume resistivity of the electrode is extremely low, less than 2 × 10 ⁻⁵ Ω · cm (20 × 10 ⁻⁶ Ω · cm). Can be maintained. The solar cell using the electrode formed in this way can maintain high conductivity and high reflectance even when used for many years, and is excellent in aging stability.

<Example 1>
First, silver nitrate was dissolved in deionized water to prepare an aqueous metal salt solution. On the other hand, granular ferrous sulfate was directly added and dissolved in a 26% concentration sodium citrate aqueous solution obtained by dissolving sodium citrate in deionized water in a nitrogen gas stream at a temperature of 35 ° C. A reducing agent aqueous solution containing ions and ferrous ions in a molar ratio of 3: 2 was prepared. Next, with the nitrogen gas stream maintained at a temperature of 35 ° C., the magnetic salt stirrer is rotated at a rotational speed of 100 rpm to stir the reducing agent aqueous solution, and the metal salt aqueous solution is added to the reducing agent aqueous solution. Dropped and mixed. 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, the reaction temperature is 40 ° C. even when the metal salt aqueous solution at room temperature is dropped. To be retained. The mixing ratio of the two aqueous solutions was 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 was 3 times as much as each other. . After the dropping of the aqueous metal salt solution was completed, the mixture was further stirred for 15 minutes to obtain a dispersion composed of metal colloid. The pH of this dispersion was 5.5, and the stoichiometric amount of metal particles in the dispersion was 5 g / liter. The obtained dispersion was allowed to stand at room temperature, and the aggregates of the precipitated metal nanoparticles were separated by decantation. After adding deionized water to this separated product to form a dispersion and desalting by ultrafiltration, the centrifugal force of this centrifuge is adjusted using a centrifuge to separate coarse particles, thereby obtaining silver nanoparticles. The particles were prepared so as to contain 75% of silver nanoparticles having a primary particle size of 10 to 50 nm in number average, that is, silver nanoparticles in the range of primary particle size of 10 to 50 nm with respect to 100% of all silver nanoparticles in number average It adjusted so that the ratio which occupies might be 75%. Further, it was then substituted and washed with 1,2-propanediol to make the metal (silver) content 70% by mass. This dispersion was designated as Example 1.

<Example 2>
The dispersion obtained in the same manner as in Example 1 was allowed to stand at room temperature, and the aggregates of the precipitated metal nanoparticles were separated by decantation. After adding deionized water to this separated product to form a dispersion and desalting by ultrafiltration, the centrifugal force of this centrifuge is adjusted using a centrifuge to separate coarse particles, thereby obtaining silver nanoparticles. The particles were prepared so as to contain 90% of silver nanoparticles having a primary particle size of 10 to 50 nm in number average, that is, the ratio of silver nanoparticles having a primary particle size of 10 to 50 nm to 100% of all silver nanoparticles in number average Was adjusted to 90%. Further, it was then substituted and washed with 1,2-propanediol to make the metal content 70% by mass. This dispersion was designated as Example 2.

<Example 3>
The dispersion obtained in the same manner as in Example 1 was allowed to stand at room temperature, and the aggregates of the precipitated metal nanoparticles were separated by decantation. After adding deionized water to this separated product to form a dispersion and desalting by ultrafiltration, the centrifugal force of this centrifuge is adjusted using a centrifuge to separate coarse particles, thereby obtaining silver nanoparticles. The particles were prepared so as to contain 100% of silver nanoparticles having a primary particle size of 10 to 50 nm in number average. Further, it was then substituted and washed with 1,2-propanediol to make the metal content 70% by mass. This dispersion was designated as Example 3.

<Example 4>
The dispersion obtained in the same manner as in Example 1 except that sodium malate was used in place of sodium citrate when preparing the reducing agent aqueous solution was allowed to stand at room temperature, and the aggregates of the precipitated metal nanoparticles were decanted. Separated by. After adding deionized water to this separated product to form a dispersion and desalting by ultrafiltration, the centrifugal force of this centrifuge is adjusted using a centrifuge to separate coarse particles, thereby obtaining silver nanoparticles. The particles were prepared so as to contain 75% of silver nanoparticles having a primary particle size of 10 to 50 nm in number average, that is, the ratio of silver nanoparticles having a primary particle size of 10 to 50 nm to 100% of all silver nanoparticles in number average Was adjusted to 75%. Further, it was then substituted and washed with 1,2-propanediol to make the metal content 70% by mass. This dispersion was designated as Example 4.

<Example 5>
The dispersion obtained in the same manner as in Example 1 except that sodium glycolate was used instead of sodium citrate when preparing the reducing agent aqueous solution was allowed to stand at room temperature, and the aggregates of the precipitated metal nanoparticles were decanted. Separated by. After adding deionized water to this separated product to form a dispersion and desalting by ultrafiltration, the centrifugal force of this centrifuge is adjusted using a centrifuge to separate coarse particles, thereby obtaining silver nanoparticles. The particles were prepared so as to contain 75% of silver nanoparticles having a primary particle size of 10 to 50 nm in number average, that is, the ratio of silver nanoparticles having a primary particle size of 10 to 50 nm to 100% of all silver nanoparticles in number average Was adjusted to 75%. Further, it was then substituted and washed with 1,2-propanediol to make the metal content 70% by mass. This dispersion was designated as Example 5.

<Example 6 >
The dispersion obtained in the same manner as in Example 1 was allowed to stand at room temperature, and the aggregates of the precipitated metal nanoparticles were separated by decantation. After adding deionized water to this separated product to form a dispersion and desalting by ultrafiltration, the centrifugal force of this centrifuge is adjusted using a centrifuge to separate coarse particles, thereby obtaining silver nanoparticles. The particles were prepared so as to contain silver nanoparticles having a primary particle size of 10 to 50 nm in a number average of 75%. That is, silver nanoparticles having a primary particle size of 10 to 50 nm accounted for 100% by mass of all silver nanoparticles in the number average. The ratio was adjusted to 75%. Further, it was subsequently substituted and washed with dimethyl sulfoxide to make the metal content 70% by mass. This dispersion was designated as Example 6 .

<Example 7 >
The dispersion obtained in the same manner as in Example 1 was allowed to stand at room temperature, and the aggregates of the precipitated metal nanoparticles were separated by decantation. After adding deionized water to this separated product to form a dispersion and desalting by ultrafiltration, the centrifugal force of this centrifuge is adjusted using a centrifuge to separate coarse particles, thereby obtaining silver nanoparticles. The particles were prepared so as to contain silver nanoparticles having a primary particle size of 10 to 50 nm in a number average of 75%. That is, silver nanoparticles having a primary particle size of 10 to 50 nm accounted for 100% by mass of all silver nanoparticles in the number average. The ratio was adjusted to 75%. Further, N-methylformamide was subsequently substituted and washed to make the metal content 70% by mass. This dispersion was designated as Example 7 .

<Example 8 >
In the same manner as in Example 1, the silver nanoparticles contain 75% of silver nanoparticles having a primary particle size of 10 to 50 nm in number average, that is, the primary particle size of 10 to 50 nm with respect to 100% of all silver nanoparticles in number average. It adjusted with the centrifuge so that the ratio for which the silver nanoparticle occupied might be 75%. Further, the first dispersion was obtained by subsequent substitution washing with 1,2-propanediol. On the other hand, the silver nitrate of Example 1 was replaced with chloroauric acid, and the gold nanoparticles contained 75% of the average number of gold nanoparticles having a primary particle size of 10 to 50 nm as in Example 1, that is, the number average. It adjusted with the centrifuge so that the ratio for which the gold nanoparticle with a primary particle diameter of 10-50 nm with respect to 100% of all the gold nanoparticles might be 75%. Further, the second dispersion was obtained by subsequent substitution washing with 1,2-propanediol. Next, the first dispersion and the second dispersion were mixed so that the silver nanoparticles were 95% by mass and the gold nanoparticles were 5% by mass. This dispersion was designated as Example 8 .

<Example 9 >
In the same manner as in Example 1, the silver nanoparticles contain 75% of silver nanoparticles having a primary particle size of 10 to 50 nm in number average, that is, the primary particle size of 10 to 50 nm with respect to 100% of all silver nanoparticles in number average. It adjusted with the centrifuge so that the ratio for which the silver nanoparticle occupied might be 75%. Further, the first dispersion was obtained by subsequent substitution washing with 1,2-propanediol. On the other hand, the silver nitrate in Example 1 was replaced with chloroplatinic acid, and the platinum nanoparticles contained 75% of the number average platinum nanoparticles having a primary particle size of 10 to 50 nm as in Example 1, that is, the number average. It adjusted with the centrifuge so that the ratio for which the platinum particle of primary particle size 10-50nm might occupy 75% with respect to 100% of all the platinum nanoparticles. Further, the second dispersion was obtained by subsequent substitution washing with 1,2-propanediol. Next, the first dispersion and the second dispersion were mixed so that the silver nanoparticles were 95% by mass and the platinum nanoparticles were 5% by mass. This dispersion was designated as Example 9 .

<Example 10 >
In the same manner as in Example 1, the silver nanoparticles contain 75% of silver nanoparticles having a primary particle size of 10 to 50 nm in number average, that is, the primary particle size of 10 to 50 nm with respect to 100% of all silver nanoparticles in number average. It adjusted with the centrifuge so that the ratio for which the silver nanoparticle occupied might be 75%. Further, the first dispersion was obtained by subsequent substitution washing with 1,2-propanediol. On the other hand, the silver nitrate of Example 1 was replaced with palladium nitrate, and in the same manner as in Example 1, the palladium nanoparticles contained 75% of the average number of palladium nanoparticles having a primary particle size of 10 to 50 nm. It adjusted with the centrifuge so that the ratio for which the palladium nanoparticle with a primary particle diameter of 10-50 nm might occupy 75% with respect to 100% of palladium nanoparticles. Further, the second dispersion was obtained by subsequent substitution washing with 1,2-propanediol. Next, the first dispersion and the second dispersion were mixed so that the silver nanoparticles were 77% by mass and the palladium nanoparticles were 23% by mass. This dispersion was designated as Example 10 .

<Example 11 >
In the same manner as in Example 1, the silver nanoparticles contain 75% of silver nanoparticles having a primary particle size of 10 to 50 nm in number average, that is, the primary particle size of 10 to 50 nm with respect to 100% of all silver nanoparticles in number average. It adjusted with the centrifuge so that the ratio for which the silver nanoparticle occupied might be 75%. Further, the first dispersion was obtained by subsequent substitution washing with 1,2-propanediol. On the other hand, the silver nitrate of Example 1 was replaced with ruthenium trichloride, and the ruthenium nanoparticles contained ruthenium nanoparticles having a primary particle diameter of 10 to 50 nm in a number average of 75% in the same manner as in Example 1, that is, the number average. The ratio of ruthenium nanoparticles having a primary particle size of 10 to 50 nm to 100% of all ruthenium particles was adjusted by a centrifuge so that the ratio was 75%. Further, the second dispersion was obtained by subsequent substitution washing with 1,2-propanediol. Next, the first dispersion and the second dispersion were mixed so that the silver nanoparticles were 80% by mass and the ruthenium nanoparticles were 20% by mass. This dispersion was designated as Example 11 .

<Example 12 >
In the same manner as in Example 1, the silver nanoparticles contain 75% of silver nanoparticles having a primary particle size of 10 to 50 nm in number average, that is, the primary particle size of 10 to 50 nm with respect to 100% of all silver nanoparticles in number average. It adjusted with the centrifuge so that the ratio for which the silver nanoparticle occupied might be 75%. Further, the first dispersion was obtained by subsequent substitution washing with 1,2-propanediol. On the other hand, the silver nitrate of Example 1 was replaced with nickel chloride, and the nickel nanoparticles contained 75% of the average number of nickel nanoparticles having a primary particle diameter of 10 to 50 nm in the same manner as in Example 1, that is, all of the number averages. The ratio of nickel nanoparticles having a primary particle size of 10 to 50 nm to 100% of nickel nanoparticles was adjusted to 75% by a centrifuge. Further, the second dispersion was obtained by subsequent substitution washing with 1,2-propanediol. Next, the first dispersion and the second dispersion were mixed so that the silver nanoparticles were 99.5% by mass and the nickel nanoparticles were 0.5% by mass. This dispersion was designated as Example 12 .

<Example 13 >
In the same manner as in Example 1, the silver nanoparticles contain 75% of silver nanoparticles having a primary particle size of 10 to 50 nm in number average, that is, the primary particle size of 10 to 50 nm with respect to 100% of all silver nanoparticles in number average. It adjusted with the centrifuge so that the ratio for which the silver nanoparticle occupied might be 75%. Further, the first dispersion was obtained by subsequent substitution washing with 1,2-propanediol. On the other hand, the silver nitrate of Example 1 is replaced with cuprous nitrate, and the copper nanoparticles contain 75% of the average number of copper nanoparticles having a primary particle size of 10 to 50 nm as in Example 1, that is, the number average. Thus, the ratio of the copper nanoparticles having a primary particle size of 10 to 50 nm to 100% of all the copper nanoparticles was adjusted to 75% by a centrifuge. Further, the second dispersion was obtained by subsequent substitution washing with 1,2-propanediol. Next, the first dispersion and the second dispersion were mixed so that the silver nanoparticles were 90% by mass and the copper nanoparticles were 10% by mass. This dispersion was designated as Example 13 .

<Example 14 >
In the same manner as in Example 1, the silver nanoparticles contain 75% of silver nanoparticles having a primary particle size of 10 to 50 nm in number average, that is, the primary particle size of 10 to 50 nm with respect to 100% of all silver nanoparticles in number average. It adjusted with the centrifuge so that the ratio for which the silver nanoparticle occupied might be 75%. Further, the first dispersion was obtained by subsequent substitution washing with 1,2-propanediol. On the other hand, the silver nitrate of Example 1 was replaced with tin dichloride, and the same manner as in Example 1, so that the tin nanoparticles contained 75% of the average number of tin nanoparticles having a primary particle size of 10 to 50 nm, that is, the number average. It adjusted with the centrifuge so that the ratio for which the tin particle of primary particle size 10-50nm might occupy 75% with respect to 100% of all the tin nanoparticles. Further, the second dispersion was obtained by subsequent substitution washing with 1,2-propanediol. Next, the first dispersion and the second dispersion were mixed so that the silver nanoparticles were 95% by mass and the tin nanoparticles were 5% by mass. This dispersion was designated as Example 14 .

<Example 15 >
In the same manner as in Example 1, the silver nanoparticles contain 75% of silver nanoparticles having a primary particle size of 10 to 50 nm in number average, that is, the primary particle size of 10 to 50 nm with respect to 100% of all silver nanoparticles in number average. It adjusted with the centrifuge so that the ratio for which the silver nanoparticle occupied might be 75%. Further, the first dispersion was obtained by subsequent substitution washing with 1,2-propanediol. On the other hand, the silver nitrate in Example 1 was replaced with indium nitrate, and in the same manner as in Example 1, the indium nanoparticles contained 75% indium nanoparticles with a primary particle size of 10 to 50 nm in number average, that is, all in number average. The amount of tin nanoparticles having a primary particle size of 10 to 50 nm with respect to 100% of the indium nanoparticles was adjusted to 75% by a centrifuge. Further, the second dispersion was obtained by subsequent substitution washing with 1,2-propanediol. Next, the first dispersion and the second dispersion were mixed so that the silver nanoparticles were 80% by mass and the indium nanoparticles were 20% by mass. This dispersion was designated as Example 15 .

<Example 16 >
In the same manner as in Example 1, the silver nanoparticles contain 75% of silver nanoparticles having a primary particle size of 10 to 50 nm in number average, that is, the primary particle size of 10 to 50 nm with respect to 100% of all silver nanoparticles in number average. It adjusted with the centrifuge so that the ratio for which the silver nanoparticle occupied might be 75%. Further, the first dispersion was obtained by subsequent substitution washing with 1,2-propanediol. On the other hand, the silver nitrate of Example 1 was replaced with zinc chloride, and in the same manner as in Example 1, the zinc nanoparticles contained 75% of zinc nanoparticles having a primary particle size of 10 to 50 nm in number average, that is, all in number average. The ratio of zinc nanoparticles having a primary particle size of 10 to 50 nm to 100% of zinc nanoparticles was adjusted to 75% by a centrifuge. Further, the second dispersion was obtained by subsequent substitution washing with 1,2-propanediol. Next, the first dispersion and the second dispersion were mixed so that the silver nanoparticles were 98% by mass and the zinc nanoparticles were 2% by mass. This dispersion was designated as Example 16 .

<Example 17 >
In the same manner as in Example 1, the silver nanoparticles contain 75% of silver nanoparticles having a primary particle size of 10 to 50 nm in number average, that is, the primary particle size of 10 to 50 nm with respect to 100% of all silver nanoparticles in number average. It adjusted with the centrifuge so that the ratio for which the silver nanoparticle occupied might be 75%. Further, the first dispersion was obtained by subsequent substitution washing with 1,2-propanediol. On the other hand, the silver nitrate of Example 1 was replaced with iron sulfate, and in the same manner as in Example 1, the iron nanoparticles contained zinc nanoparticles having a primary particle size of 10 to 50 nm in a number average of 75%, that is, all in number average. The ratio of iron nanoparticles having a primary particle diameter of 10 to 50 nm to 100% of iron nanoparticles was adjusted to 75% by a centrifuge. Further, the second dispersion was obtained by subsequent substitution washing with 1,2-propanediol. Next, the first dispersion and the second dispersion were mixed so that the silver nanoparticles were 95% by mass and the iron nanoparticles were 5% by mass. This dispersion was designated as Example 17 .

<Example 18 >
In the same manner as in Example 1, the silver nanoparticles contain 75% of silver nanoparticles having a primary particle size of 10 to 50 nm in number average, that is, the primary particle size of 10 to 50 nm with respect to 100% of all silver nanoparticles in number average. It adjusted with the centrifuge so that the ratio for which the silver nanoparticle occupied might be 75%. Further, the first dispersion was obtained by subsequent substitution washing with 1,2-propanediol. On the other hand, the silver nitrate of Example 1 was replaced with chromium sulfate, and the chromium nanoparticles contained 75% of the average number of chromium nanoparticles having a primary particle size of 10 to 50 nm in the same manner as in Example 1, that is, all the chromium nanoparticles were averaged. It adjusted with the centrifuge so that the ratio for which the primary particle diameter of 10-50 nm of chromium nanoparticles with respect to 100% of particles might be 75%. Further, the second dispersion was obtained by subsequent substitution washing with 1,2-propanediol. Next, the first dispersion and the second dispersion were mixed so that the silver nanoparticles were 95% by mass and the chromium nanoparticles were 5% by mass. This dispersion was designated as Example 18 .

<Example 19 >
In the same manner as in Example 1, the silver nanoparticles contain 75% of silver nanoparticles having a primary particle size of 10 to 50 nm in number average, that is, the primary particle size of 10 to 50 nm with respect to 100% of all silver nanoparticles in number average. It adjusted with the centrifuge so that the ratio for which the silver nanoparticle occupied might be 75%. Further, the first dispersion was obtained by subsequent substitution washing with 1,2-propanediol. On the other hand, the silver nitrate of Example 1 was replaced with manganese sulfate, and in the same manner as in Example 1, the manganese nanoparticles contained 75% of the average number of manganese nanoparticles having a primary particle size of 10 to 50 nm. It adjusted with the centrifuge so that the ratio for which the manganese nanoparticle with a primary particle diameter of 10-50 nm might occupy 75% with respect to 100% of manganese nanoparticles. Further, the second dispersion was obtained by subsequent substitution washing with 1,2-propanediol. Next, the first dispersion and the second dispersion were mixed so that the silver nanoparticles were 95% by mass and the manganese nanoparticles were 5% by mass. This dispersion was designated as Example 19 .

<Comparative Example 1>
The dispersion obtained in the same manner as in Example 1 was allowed to stand at room temperature, and the aggregates of the precipitated metal nanoparticles were separated by decantation. After adding deionized water to this separated product to form a dispersion and desalting by ultrafiltration, the centrifugal force of this centrifuge is adjusted using a centrifuge to separate coarse particles, thereby obtaining silver nanoparticles. The particles were prepared so as to contain 75% of silver nanoparticles having a primary particle size of 10 to 50 nm in number average, that is, the ratio of silver nanoparticles having a primary particle size of 10 to 50 nm to 100% of all silver nanoparticles in number average Was adjusted to 75%. Subsequently, the amount of deionized water was adjusted so that the metal content was 70%. This dispersion was designated as Comparative Example 1.

<Comparative example 2>
The dispersion obtained in the same manner as in Example 1 was allowed to stand at room temperature, and the aggregates of the precipitated metal nanoparticles were separated by decantation. After adding deionized water to this separated product to form a dispersion and desalting by ultrafiltration, the centrifugal force of this centrifuge is adjusted using a centrifuge to separate coarse particles, thereby obtaining silver nanoparticles. The particles were prepared so as to contain 90% of silver nanoparticles having a primary particle size of 10 to 50 nm in number average, that is, the ratio of silver nanoparticles having a primary particle size of 10 to 50 nm to 100% of all silver nanoparticles in number average Was adjusted to 75%. Further, it was subsequently substituted and washed with 1-methoxy-2-propanol to make the metal content 70% by mass. This dispersion was designated as Comparative Example 2.

<Comparative Example 3>
The dispersion obtained in the same manner as in Example 1 was allowed to stand at room temperature, and the aggregates of the precipitated metal nanoparticles were separated by decantation. After adding deionized water to this separated product to form a dispersion and desalting by ultrafiltration, the centrifugal force of this centrifuge is adjusted using a centrifuge to separate coarse particles, thereby obtaining silver nanoparticles. The particles were prepared so as to contain 90% of silver nanoparticles having a primary particle size of 10 to 50 nm in number average, that is, the ratio of silver nanoparticles having a primary particle size of 10 to 50 nm to 100% of all silver nanoparticles in number average Was adjusted to 75%. Further, it was subsequently substituted and washed with toluene to make the metal content 70% by mass. This dispersion was designated as Comparative Example 3.

<Comparative test 1 and evaluation>
The dispersions of Examples 1 to 19 and Comparative Examples 1 to 3 are shown in the following Tables 3 and 4 so that the film thickness after firing is 1 μm on the substrates shown in the following Tables 3 and 4. The coating method was applied. ITO or PET was used as the substrate. As the coating method, knife coating or spin coating was used. Here, about the coating film which apply | coated the dispersion material on the base material, the coating property was confirmed visually. Subsequently, the coating films of Examples 1 to 19 were baked at the temperatures shown in the following Table 3 to form electrodes on the substrate. Before performing the weather resistance test on the base material on which these electrodes are formed, the reflectance and conductivity of the electrode formed on each base material are measured, and after the weather resistance test is performed, each electrode is formed on each base material. The reflectivity and conductivity of the prepared electrodes were measured. The results are shown in Table 3. Moreover, the state of the coating film about Comparative Examples 1-3 was observed. The results are shown in Table 4.

  In addition, the weather resistance test was performed by accommodating the substrate on which the electrode was formed in a constant temperature and humidity chamber having a temperature of 100 ° C. and a humidity of 50% for 1000 hours.

  The reflectance was measured by irradiating an electrode with electromagnetic waves (infrared rays and visible rays) having a wavelength of 750 to 1500 nm, and measuring the reflected electromagnetic waves using an ultraviolet-visible spectrophotometer (V-570: manufactured by JASCO Corporation). The ratio (%) of the reflection amount with respect to the irradiation amount was calculated and obtained.

  The primary particle size of the metal nanoparticles is measured using FE-TEM (field emission transmission electron microscope: manufactured by JEOL Ltd.), and the proportion of silver nanoparticles having a primary particle size of 10 to 50 nm is determined by the above FE. -From the photograph of the primary particle diameter of the metal nanoparticles photographed using TEM, the number of particle diameters was measured and evaluated.

  The conductivity was determined as a volume resistivity (Ω · cm) measured and calculated by the four probe method. Specifically, the volume resistivity of the electrode is determined by first measuring the thickness of the electrode after firing directly from the electrode cross section using an SEM (Electron Microscope S800: manufactured by Hitachi, Ltd.), Using a specific resistance measuring instrument (Loresta: manufactured by Mitsubishi Chemical Corporation) by the terminal method, the measured thickness of the electrode was input to this measuring instrument.

On the other hand, in Tables 1 and 2, the proportion of metal nanoparticles having a primary particle size of 10 to 50 nm in the dispersions of Examples 1 to 19 and Comparative Examples 1 to 3, carbon number of organic molecular main chain, and dispersion Shows the type and mixing ratio of (composition) and the type and content of dissimilar metals (metals other than silver) (content of dissimilar metals when the total of metals other than silver and silver is 100% by mass). It was. Tables 3 and 4 show the type of substrate, coating properties, and firing temperature, as well as reflectance, conductivity (volume resistivity), and weather resistance. In the column of coating property in Table 3 and Table 4, “good” indicates a case where the coating was uniformly applied on the base material, and “bad” indicates that the base material repels the dispersion that becomes the coating liquid. The case where it was not able to apply uniformly on a base material is shown. Furthermore, in the weather resistance column of Table 3, “good” indicates a case where the reflectance is 80% or more and the volume resistivity is less than 20 × 10 ⁻⁶ Ω · cm. The reflectance is less than 80% and the volume resistivity is less than 20 × 10 ⁻⁶ Ω · cm, or the reflectance is 80% or more and the volume resistivity exceeds 20 × 10 ⁻⁶ Ω · cm. Or the reflectance is less than 80% and the volume resistivity exceeds 20 × 10 ⁻⁶ Ω · cm.

表３及び表４から明らかなように、比較例１〜３では、塗工性が悪く、塗膜の状態が、斑になったり、膜に多くの穴が形成されたりと、太陽電池の電極を形成するための組成物として使用するのには不適であることが確認された。これらに対し、実施例１〜１９では、基材への塗膜性はいずれも良好であり、耐候性試験前及び耐候性試験後のいずれであっても、電極の反射率が８０％以上でありかつ体積抵抗率が２０×１０^-6Ω・ｃｍ未満であり、耐候性試験前の初期特性も耐候性も十分に満足するものとなった。

As is clear from Tables 3 and 4, in Comparative Examples 1 to 3, the coatability is poor, the state of the coating film becomes uneven, and many holes are formed in the film. It was confirmed that it was unsuitable for use as a composition for forming the. For these, in Examples 1 19 are both coating properties to the substrate was good, be any of before and after weather resistance test and weathering resistance test, in the reflectivity of the electrode is 80% or more In addition, the volume resistivity was less than 20 × 10 ⁻⁶ Ω · cm, and the initial characteristics before the weather resistance test and the weather resistance were sufficiently satisfied.

Claims (1)

Preparing a reducing agent aqueous solution by dissolving by adding concentration 10-40% of granular or powdery ferrous sulfate aqueous sodium citrate solution in a stream of inert gas,
While stirring the reducing agent aqueous solution in an inert gas stream , the silver nitrate aqueous solution is added dropwise to the reducing agent aqueous solution, and the addition amount of the silver nitrate aqueous solution is dropped and mixed so that it is 1/10 or less of the amount of the reducing agent aqueous solution. And a process of
A step of stirring the mixture for 10 to 300 minutes to prepare a dispersion composed of metal colloid;
Separating the dispersion of the metal colloid from the dispersion by allowing the dispersion of metal nanoparticles to stand at room temperature and sedimenting the aggregated metal nanoparticles;
Adding water to the separated product to form a dispersion;
Dispersion of coarse particles obtained by desalting the dispersion by ultrafiltration to separate a metal nanoparticle dispersion containing 70% or more of metal nanoparticles having a primary particle size in the range of 10 to 50 nm. Obtaining
Look including a step of obtaining the metal nanoparticle dispersion of 1,2-propanediol, dimethyl sulfoxide or N- either the electrode-forming composition of the solar cell was replaced washed methyl formamide,
The sodium citrate aqueous solution is obtained by dissolving sodium citrate in deionized water. The metal nanoparticles are dispersed in a dispersion medium, the metal nanoparticles are 75% by mass or more of silver nanoparticles, and 0.0. It contains Au, Pt, Pd, Ru, Ni, Cu, Sn, In, Zn, Fe, Cr, or Mn nanoparticles in an amount of 02% by mass or more and less than 25% by mass. Are chemically modified with a protective agent for the organic molecular main chain of 1 to 3, and the metal nanoparticles contain 70% or more of metal nanoparticles having a primary particle size in the range of 10 to 50 nm in terms of number average; A method for producing a composition for forming an electrode of a solar cell, wherein the composition is any one of 2-propanediol, dimethyl sulfoxide, and N-methylformamide, and the metal content is in the range of 2.5 to 95% by mass .