WO2014203897A1 - Electrically conductive composition and solar cell - Google Patents

Electrically conductive composition and solar cell Download PDF

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Publication number
WO2014203897A1
WO2014203897A1 PCT/JP2014/066041 JP2014066041W WO2014203897A1 WO 2014203897 A1 WO2014203897 A1 WO 2014203897A1 JP 2014066041 W JP2014066041 W JP 2014066041W WO 2014203897 A1 WO2014203897 A1 WO 2014203897A1
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Prior art keywords
silver salt
conductive composition
fatty acid
acid silver
electrode
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PCT/JP2014/066041
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French (fr)
Japanese (ja)
Inventor
奈央 佐藤
石川　和憲
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横浜ゴム株式会社
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Priority to JP2015522935A priority Critical patent/JPWO2014203897A1/en
Priority to KR1020167000003A priority patent/KR20160021178A/en
Publication of WO2014203897A1 publication Critical patent/WO2014203897A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/08—Metals
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/04—Oxygen-containing compounds
    • C08K5/09—Carboxylic acids; Metal salts thereof; Anhydrides thereof
    • C08K5/098—Metal salts of carboxylic acids
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L63/00—Compositions of epoxy resins; Compositions of derivatives of epoxy resins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/20—Conductive material dispersed in non-conductive organic material
    • H01B1/22—Conductive material dispersed in non-conductive organic material the conductive material comprising metals or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0224—Electrodes
    • H01L31/022408—Electrodes for devices characterised by at least one potential jump barrier or surface barrier
    • H01L31/022425—Electrodes for devices characterised by at least one potential jump barrier or surface barrier for solar cells
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/08—Metals
    • C08K2003/085—Copper
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy

Definitions

  • the present invention relates to a conductive composition and a solar battery cell using the same as a collecting electrode.
  • conductive particles such as silver particles, binders made of thermoplastic resin (eg, acrylic resin, vinyl acetate resin, etc.) or thermosetting resin (eg, epoxy resin, unsaturated polyester resin, etc.), organic solvent, curing
  • thermoplastic resin eg, acrylic resin, vinyl acetate resin, etc.
  • thermosetting resin eg, epoxy resin, unsaturated polyester resin, etc.
  • organic solvent curing
  • a substrate for example, a silicon substrate, an epoxy resin substrate, etc.
  • Patent Document 2 “a conductive composition containing silver powder (A), a fatty acid silver salt (B), a resin (C), and a solvent (D),
  • the fatty acid silver salt (B) is a compound having one carboxy silver base (—COOAg) and one or two hydroxyl groups (—OH), and the content of silver oxide is the solvent (D)
  • a conductive composition that is 10 parts by mass or less with respect to 100 parts by mass has been proposed ([Claim 1]).
  • the copper fine particles are employed as the metal fine particles in the metal fine particle ink paste described in Patent Document 1, or when the silver powder of the conductive composition described in Patent Document 2 is changed to copper powder, the copper particles It has been clarified that the volume resistivity of formed electrodes and wirings (hereinafter also referred to as “electrodes”) may be increased depending on the usage environment due to oxidation of at least a part of the surface of the electrode. .
  • an object of the present invention is to provide a conductive composition capable of forming an electrode or the like having a low volume resistivity and a solar battery cell using the same as a collecting electrode.
  • the present inventors have found that in a conductive composition containing copper powder, a fatty acid silver salt and a thermosetting resin, there is a difference between the thermal decomposition peak temperature and the thermal decomposition start temperature.
  • a specific amount of fatty acid silver salt at 40 ° C. or higher, it was found that the volume resistivity of the formed electrode or the like was lowered, and the present invention was completed. That is, the present inventors have found that the above problem can be solved by the following configuration.
  • a conductive composition comprising copper powder (A), a fatty acid silver salt (B), and a thermosetting resin (C),
  • the difference between the thermal decomposition peak temperature of the fatty acid silver salt (B) and the thermal decomposition start temperature is 40 ° C. or higher
  • the content of the fatty acid silver salt (B) is 20 to 100 parts by mass with respect to 100 parts by mass of the copper powder (A) in terms of the amount of silver produced from the fatty acid silver salt (B).
  • Conductive composition (2) The conductive composition according to (1), wherein the content of the thermosetting resin (C) is 1 to 50 parts by mass with respect to 100 parts by mass of the copper powder (A).
  • a solar battery cell using the conductive composition according to (1) or (2) above as a collecting electrode is a collecting electrode.
  • the present invention it is possible to provide a conductive composition capable of forming an electrode or the like having a low volume resistivity, and a solar battery cell using the same as a collecting electrode. Further, by using the conductive composition of the present invention, an electrode having a low volume resistivity can be formed even when firing at a low temperature to a medium temperature (less than 450 ° C.), particularly at a low temperature (about 150 to 350 ° C.). Therefore, the solar cell (especially the second preferred embodiment described later) has an effect of reducing damage caused by heat, which is very useful. Furthermore, if the conductive composition of the present invention is used, an electronic circuit, an antenna, etc. not only on a material having high heat resistance such as indium tin oxide (ITO) or silicon but also on a material having low heat resistance such as PET film. This circuit is very useful because it can be manufactured easily and in a short time.
  • ITO indium tin oxide
  • PET film a material having low heat resistance
  • FIG. 1 is a cross-sectional view showing a first preferred embodiment of a solar battery cell.
  • FIG. 2 is a cross-sectional view showing a second preferred embodiment of the solar battery cell.
  • the conductive composition of the present invention is a conductive composition having copper powder (A), a fatty acid silver salt (B), and a thermosetting resin (C).
  • the electrically conductive composition of this invention may contain a hardening
  • the electrically conductive composition of this invention may contain the solvent (E) as needed from viewpoints of printability etc. so that it may mention later.
  • an electrode having a low volume resistivity can be formed.
  • Composition This is not clear in detail, but is estimated to be as follows. That is, by using the fatty acid silver salt (B) having a difference between the thermal decomposition peak temperature and the thermal decomposition starting temperature of 40 ° C. or more, silver is produced from the fatty acid silver salt in a wide temperature range, and the silver is the surface of the copper particles. It is considered that the surface oxidation of the copper particles could be suppressed by efficiently covering the surface.
  • the copper powder (A) used in the conductive composition of the present invention is not particularly limited, and those blended with conventionally known conductive pastes can be used.
  • the copper powder (A) preferably has an average particle diameter of 1.0 to 20 ⁇ m because it has good printability and can form an electrode having a smaller volume resistivity. It is more preferably 0 to 10 ⁇ m.
  • the average particle diameter means an average value of the particle diameters, and is measured by using a laser diffraction / scattering type particle size distribution measuring apparatus, and the 50% volume cumulative diameter (D50) calculated using the particle diameter standard as the number is used.
  • D50 volume cumulative diameter
  • a commercially available product can be used as such copper powder (A).
  • Specific examples thereof include Cu-HWQ (average particle size: 3.0 ⁇ m, manufactured by Fukuda Metal Foil Powder Co., Ltd.), FCC. -TBX (average particle size: 5.05 ⁇ m, manufactured by Fukuda Metal Foil Powder Co., Ltd.)
  • the fatty acid silver salt (B) used in the conductive composition of the present invention is a fatty acid silver salt in which the difference between the thermal decomposition peak temperature and the thermal decomposition start temperature is 40 ° C. or higher.
  • the pyrolysis peak temperature is a value measured in the temperature range from room temperature to 300 ° C. in the air at a temperature rising rate of 5 ° C./min using a differential thermal-thermogravimetric simultaneous measurement device (TG-DTA). The exothermic peak temperature appearing in the DTA curve.
  • the pyrolysis start temperature is measured in the temperature range from room temperature to 300 ° C.
  • the fatty acid silver salt (B) has a difference between the thermal decomposition peak temperature and the thermal decomposition starting temperature of 100 ° C. or more because it can form an electrode having a low volume resistivity after the wet heat test.
  • the temperature is preferably 100 to 130 ° C. This is presumably because the surface of the copper powder (A) could be more efficiently coated with silver derived from the reduction of the fatty acid silver salt (B).
  • the fatty acid silver salt (B) is not particularly limited as long as the difference between the thermal decomposition peak temperature and the thermal decomposition start temperature is 40 ° C. or higher among the silver salts of organic carboxylic acids.
  • JP-A-2008-198595 Fatty acid metal salts (particularly tertiary fatty acid silver salts) described in paragraphs [0063] to [0068] of the gazette fatty acid silver described in paragraph [0030] of Japanese Patent No. 4482930, JP 2010-92684 A Secondary fatty acid silver salts described in the paragraphs [0046] to [0056] of the above can be used.
  • the content of the fatty acid silver salt (B) is 20 to 100 with respect to 100 parts by mass of the copper powder (A) in terms of the amount of silver produced from the fatty acid silver salt (B). Parts by mass, preferably 30 to 100 parts by mass, and more preferably 40 to 100 parts by mass.
  • thermosetting resin (C) used in the conductive composition of the present invention is not particularly limited, and specific examples thereof include an epoxy resin, a polyester resin, a silicone resin, a urethane resin, and the like. You may use, and may use 2 or more types together. Among these, an epoxy resin is preferable because it has a strong adhesion to a silicon substrate and high heat and humidity resistance.
  • the epoxy resin as a suitable example of the thermosetting resin (C) is not particularly limited as long as it is a resin composed of a compound having two or more oxirane rings (epoxy groups) in one molecule.
  • the equivalent is 90-2000.
  • a conventionally well-known epoxy resin can be used as such an epoxy resin.
  • epoxy compounds having a bisphenyl group such as bisphenol A type, bisphenol F type, brominated bisphenol A type, hydrogenated bisphenol A type, bisphenol S type, bisphenol AF type, biphenyl type, and polyalkylene Bifunctional glycidyl ether type epoxy resins such as glycol type, alkylene glycol type epoxy compounds, epoxy compounds having a naphthalene ring, and epoxy compounds having a fluorene group; Polyfunctional glycidyl ether type epoxy resins such as phenol novolac type, orthocresol novolak type, trishydroxyphenylmethane type, tetraphenylolethane type; Glycidyl ester epoxy resins of synthetic fatty acids such as dimer acid; N, N, N ′, N′-tetraglycidyldiaminodiphenylmethane (TGDDM), tetraglycidyldiaminodiphenylsulfone (TGDDM), te
  • epoxy resins may be used alone or in combination of two or more.
  • bisphenol A type epoxy resins and bisphenol F type epoxy resins are preferable from the viewpoints of curability, heat resistance, durability, and cost.
  • the content of the thermosetting resin (C) is 1.0 to 100 parts by mass with respect to 100 parts by mass of the copper powder (A) because the volume resistivity of the formed electrode or the like is lower.
  • the amount is preferably 50 parts by mass, more preferably 2 to 25 parts by mass.
  • the conductive composition of the present invention preferably contains a curing agent (D) composed of a complex of boron trifluoride and an amine compound.
  • a complex of boron trifluoride and an amine compound a complex of boron trifluoride and an aliphatic amine (aliphatic primary amine, aliphatic secondary amine, aliphatic tertiary amine), trifluoride
  • examples thereof include a complex of boron and an alicyclic amine, a complex of boron trifluoride and an aromatic amine, a complex of boron trifluoride and a heterocyclic amine, and the like.
  • the heterocyclic amine may be an alicyclic heterocyclic amine (hereinafter also referred to as an alicyclic heterocyclic amine) or an aromatic heterocyclic amine (hereinafter also referred to as an aromatic heterocyclic amine). Also good.
  • Specific examples of the aliphatic primary amine include methylamine, ethylamine, n-propylamine, iso-propylamine, n-butylamine, iso-butylamine, sec-butylamine, n-hexylamine, n-octylamine, 2 -Ethylhexylamine, laurylamine and the like.
  • aliphatic secondary amine examples include dimethylamine, diethylamine, methylethylamine, methylpropylamine, di-iso-propylamine, di-n-propylamine, ethylpropylamine, di-n-butylamine, di- Examples include iso-butylamine, dipropenylamine, chlorobutylpropylamine, di (chlorobutyl) amine, di (bromoethyl) amine and the like.
  • Specific examples of the aliphatic tertiary amine include trimethylamine, triethylamine, tributylamine, triethanolamine and the like.
  • alicyclic amine examples include cyclohexylamine.
  • aromatic amines include benzylamine.
  • alicyclic heterocyclic amine examples include pyrrolidine, piperidine, 2-pipecoline, 3-pipecoline, 4-pipecoline, 2,4-lupetidine, 2,6-lupetidine, 3,5-lupetidine, piperazine, and homopiperazine.
  • aromatic heterocyclic amine examples include pyridine, pyrrole, imidazole, pyridazine, pyrimidine, quinoline, triazine, tetrazine, isoquinoline, quinazoline, naphthyridine, pteridine, acridine, phenazine and the like.
  • the curing agent (D) is selected from the group consisting of boron trifluoride piperidine, boron trifluoride ethylamine, and boron trifluoride triethanolamine because the volume resistivity of the formed electrode or the like is lower. A complex is preferred.
  • the content of the curing agent (D) is preferably 1 to 15 parts by mass with respect to 100 parts by mass of the epoxy resin, because the volume resistivity of the formed electrode or the like becomes lower. It is more preferable that it is 10 mass parts.
  • the conductive composition of the present invention preferably contains a solvent (E) from the viewpoint of workability such as printability.
  • the solvent (E) is not particularly limited as long as it can apply the conductive composition of the present invention onto a substrate. Specific examples thereof include butyl carbitol, methyl ethyl ketone, isophorone, ⁇ -terpineol. These may be used, and these may be used alone or in combination of two or more.
  • the electrically conductive composition of this invention may contain additives, such as a reducing agent, as needed.
  • a reducing agent include ethylene glycols.
  • the manufacturing method of the electrically conductive composition of this invention is not specifically limited,
  • (D) the method of mixing the said solvent (E), an additive, etc. with a roll, a kneader, an extruder, a universal stirrer etc. is mentioned.
  • the solar battery cell of the present invention is a solar battery cell using the above-described conductive composition of the present invention as a collecting electrode.
  • a 1st suitable aspect of the photovoltaic cell of this invention comprises the surface electrode by the side of a light-receiving surface, a semiconductor substrate, and a back electrode,
  • the said surface electrode and / or the said back electrode are the electroconductivity of this invention mentioned above.
  • a solar battery cell formed using the composition can be mentioned.
  • the 1st suitable aspect of the photovoltaic cell of this invention is demonstrated using FIG.
  • the solar cell 1 includes a surface electrode 4 on the light receiving surface side, a pn junction silicon substrate 7 in which a p layer 5 and an n layer 2 are joined, and a back electrode 6.
  • the solar battery cell 1 is preferably provided with an antireflection film 3, for example, by etching the wafer surface to form a pyramidal texture in order to reduce reflectivity.
  • an antireflection film 3 for example, by etching the wafer surface to form a pyramidal texture in order to reduce reflectivity.
  • the arrangement (pitch), shape, height, width and the like of the electrode are not particularly limited.
  • the height of the electrode is usually designed to be several to several tens of ⁇ m, but the ratio of the height and width of the cross section of the electrode formed using the conductive composition of the present invention (height / width) (below) , “Aspect ratio”) can be adjusted to a large value (for example, about 0.4 or more).
  • the front surface electrode and the back surface electrode usually have a plurality, but, for example, only a part of the plurality of surface electrodes is formed of the conductive composition of the present invention.
  • part of the plurality of front surface electrodes and part of the plurality of back surface electrodes may be formed of the conductive composition of the present invention.
  • the antireflection film is a film (film thickness: about 0.05 to 0.1 ⁇ m) formed on a portion of the light receiving surface where the surface electrode is not formed.
  • a silicon oxide film, a silicon nitride film, a titanium oxide It is comprised from a film
  • the silicon substrate has a pn junction, which means that a second conductivity type light-receiving surface impurity diffusion region is formed on the surface side of the first conductivity type semiconductor substrate.
  • the second conductivity type is p-type.
  • the impurity imparting p-type include boron and aluminum
  • examples of the impurity imparting n-type include phosphorus and arsenic.
  • the silicon substrate is not particularly limited, and a known silicon substrate (plate thickness: about 80 to 450 ⁇ m) for forming a solar cell can be used, and either a monocrystalline or polycrystalline silicon substrate can be used. Good.
  • the solar battery cell has a large electrode aspect ratio because the surface electrode and / or the back electrode is formed using the conductive composition of the present invention.
  • the electromotive force generated by light reception can be efficiently taken out as a current.
  • the conductive composition of the present invention described above can also be applied to the formation of the back electrode of an all-back electrode type (so-called back contact type) solar cell, it can also be applied to an all-back electrode type solar cell. Can do.
  • the manufacturing method of a photovoltaic cell (1st suitable aspect) is not specifically limited,
  • the antireflection film can be formed by a known method such as a plasma CVD method.
  • the wiring formation step is a step of forming a wiring by applying the conductive composition of the present invention on a silicon substrate.
  • specific examples of the coating method include inkjet, screen printing, gravure printing, offset printing, letterpress printing, and the like.
  • the heat treatment step is a step of forming a conductive wiring (electrode) by heat-treating the coating film formed in the wiring forming step.
  • a conductive wiring electrode
  • the heat treatment step is a step of forming a conductive wiring (electrode) by heat-treating the coating film formed in the wiring forming step.
  • the heat treatment is not particularly limited, but is preferably a treatment in which heating (firing) is performed at a relatively low temperature of 150 to 350 ° C. for several seconds to several tens of minutes. When the temperature and time are within this range, an electrode can be easily formed even when an antireflection film is formed on a silicon substrate. Further, in the first preferred embodiment of the solar battery cell of the present invention, since the conductive composition of the present invention is used, good heat treatment (firing) can be achieved even at a relatively low temperature of 150 to 350 ° C. ) Can be applied.
  • the heat treatment step may be performed by irradiation with ultraviolet rays or infrared rays.
  • the solar battery cell 100 has an n-type single crystal silicon substrate 11 as a center, i-type amorphous silicon layers 12 a and 12 b, and p-type amorphous silicon layers 13 a and n-type amorphous silicon layers above and below it. 13b, transparent conductive layers 14a and 14b, and current collecting electrodes 15a and 15b formed using the above-described conductive composition of the present invention.
  • the n-type single crystal silicon substrate is a single crystal silicon layer doped with an n-type impurity. Impurities that give n-type are as described above.
  • the i-type amorphous silicon layer is an undoped amorphous silicon layer.
  • the p-type amorphous silicon is an amorphous silicon layer doped with an impurity imparting p-type. Impurities that give p-type are as described above.
  • the n-type amorphous silicon is an amorphous silicon layer doped with an n-type impurity. Impurities that give n-type are as described above.
  • the said collector electrode is a collector electrode formed using the electrically conductive composition of this invention mentioned above. A specific aspect of the current collecting electrode is the same as that of the front surface electrode or the back surface electrode described above.
  • Transparent conductive layer Specific examples of the material for the transparent conductive layer include single metal oxides such as zinc oxide, tin oxide, indium oxide, and titanium oxide, indium tin oxide (ITO), indium zinc oxide, indium titanium oxide, tin cadmium oxide, Various metal oxides such as gallium-doped zinc oxide, aluminum-doped zinc oxide, boron-doped zinc oxide, titanium-doped zinc oxide, titanium-doped indium oxide, zirconium-doped indium oxide, and fluorine-doped tin oxide. Can be mentioned.
  • ITO indium tin oxide
  • ITO indium zinc oxide
  • titanium oxide titanium oxide
  • tin cadmium oxide Various metal oxides such as gallium-doped zinc oxide, aluminum-doped zinc oxide, boron-doped zinc oxide, titanium-doped zinc oxide, titanium-doped indium oxide, zirconium-doped indium oxide, and fluorine-doped
  • the method for producing the solar battery cell is not particularly limited, and can be produced by, for example, the method described in JP 2010-34162 A.
  • the i-type amorphous silicon layer 12a is formed on one main surface of the n-type single crystal silicon substrate 11 by a PECVD (plasma enhanced chemical vapor deposition) method or the like.
  • a p-type amorphous silicon layer 13a is formed on the formed i-type amorphous silicon layer 12a by PECVD or the like.
  • an i-type amorphous silicon layer 12b is formed on the other main surface of the n-type single crystal silicon substrate 11 by PECVD or the like. Further, an n-type amorphous silicon layer 13b is formed on the formed i-type amorphous silicon layer 12b by PECVD or the like.
  • transparent conductive layers 14a and 14b such as ITO are formed on the p-type amorphous silicon layer 13a and the n-type amorphous silicon layer 13b by sputtering or the like.
  • the conductive composition of the present invention is applied on the formed transparent conductive layers 14a and 14b to form wirings, and the formed wirings are heat-treated to form current collecting electrodes 15a and 15b.
  • the method for forming the wiring is the same as the method described in the wiring formation step of the above-described solar battery cell (first preferred embodiment).
  • the method of heat-treating the wiring is the same as the method described in the heat treatment step of the above-described solar battery cell (first preferred embodiment), but the heat treatment temperature (firing temperature) is preferably 150 to 200 ° C.
  • Examples 1 to 17, Comparative Examples 1 to 6 The copper powder etc. which are shown in the following 2nd table
  • ⁇ Adhesion> The evaluation of the adhesion of each formed conductive film to the substrate was performed by a grid peel test. The results are shown in Table 2 below. Specifically, on each of the obtained substrates with conductive coating, 100 1 mm bases (10 ⁇ 10) were made, and cellophane adhesive tape was completely attached on the bases and rubbed 10 times with the belly of the finger. After that, one end of the tape was momentarily pulled apart while keeping one end of the tape at right angles to the conductive film, and the number of base meshes remaining without being completely peeled was examined. It is most preferable that the number of base meshes remaining without being completely peeled is 100, that is, those having not peeled off at all.
  • Copper powder Cu-HWQ (shape: spherical, average particle size: 3.0 ⁇ m, manufactured by Fukuda Metal Foil Powder Industry)
  • Silver salt of 2-methylpropanoate 50 g of silver oxide (manufactured by Toyo Kagaku Kogyo Co., Ltd.), 38 g of 2-methylpropanoic acid (manufactured by Kanto Chemical Co., Ltd.) and 300 g of methyl ethyl ketone (MEK) were placed in a ball mill and reacted by stirring at room temperature for 24 hours. Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare silver 2-methylpropanoate.
  • MEK methyl ethyl ketone
  • 2-ethylbutyric acid silver salt 50 g of silver oxide (manufactured by Toyo Chemical Co., Ltd.), 50.13 g of 2-ethylbutyric acid (manufactured by Kanto Chemical Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours. Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare silver 2-ethylbutyrate.
  • Neodecanoic acid silver salt 50 g of silver oxide (manufactured by Toyo Kagaku Kogyo Co., Ltd.), 74.3 g of neodecanoic acid (manufactured by Toyo Gosei Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours. Next, MEK was removed by suction filtration, and the obtained powder was dried to prepare a silver neodecanoate.
  • 2-ethylhexanoic acid silver salt 50 g of silver oxide (manufactured by Toyo Chemical Co., Ltd.), 49.27 g of 2-ethylhexanoic acid (manufactured by Kanto Chemical Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours. Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare silver 2-ethylhexanoate.
  • -Silver stearate 50 g of silver oxide (manufactured by Toyo Chemical Co., Ltd.), 123 g of stearic acid (manufactured by Kanto Chemical Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours. Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare a silver stearate salt.
  • 1,2,3,4-Butanetetracarboxylic acid silver salt First, 50 g of silver oxide (manufactured by Toyo Kagaku Kogyo Co., Ltd.), 25.29 g of 1,2,3,4-butanetetracarboxylic acid (manufactured by Shin Nippon Chemical Co., Ltd.) and 300 g of MEK are put into a ball mill and stirred at room temperature for 24 hours. Was reacted. Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare 1,2,3,4-butanetetracarboxylic acid silver salt.
  • Glutaric acid silver salt 50 g of silver oxide (manufactured by Toyo Chemical Co., Ltd.), 28.5 g of glutaric acid (manufactured by Kanto Chemical Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours. Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare silver glutarate.
  • N-butyric acid silver salt 50 g of silver oxide (manufactured by Toyo Chemical Co., Ltd.), 38.01 g of n-butyric acid (manufactured by Kanto Chemical Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours. Next, MEK was removed by suction filtration, and the obtained powder was dried to prepare silver n-butyrate.
  • Silver laurate salt 40 g of silver oxide (manufactured by Toyo Chemical Co., Ltd.), 68 g of lauric acid (manufactured by Kanto Chemical Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours. Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare silver laurate.
  • 4-cyclohexene-1,2-dicarboxylic acid silver salt 50 g of silver oxide (manufactured by Toyo Kagaku Kogyo Co., Ltd.), 36.67 g of 4-cyclohexene-1,2-dicarboxylic acid (manufactured by Shin Nippon Chemical Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours. . Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare silver 4-cyclohexene-1,2-dicarboxylate.
  • Azelaic acid silver salt 50 g of silver oxide (manufactured by Toyo Chemical Co., Ltd.), 40.60 g of azelaic acid (manufactured by Kanto Chemical Co., Ltd.) and 300 g of MEK were put into a ball mill and reacted by stirring at room temperature for 24 hours. Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare azelaic acid silver salt.
  • 2,2-bis (hydroxymethyl) -n-butyric acid silver salt 50 g of silver oxide (manufactured by Toyo Kagaku Kogyo Co., Ltd.), 64 g of 2,2-bis (hydroxymethyl) -n-butyric acid (manufactured by Tokyo Chemical Industry Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours. . Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare 2,2-bis (hydroxymethyl) -n-butyric acid silver salt.
  • 2-hydroxyisobutyric acid silver salt 50 g of silver oxide (manufactured by Toyo Kagaku Kogyo Co., Ltd.), 45 g of 2-hydroxyisobutyric acid (manufactured by Tokyo Chemical Industry Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours. Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare silver 2-hydroxyisobutyrate.
  • Silver glycolate 50 g of silver oxide (manufactured by Toyo Chemical Co., Ltd.), 16.40 g of glycolic acid (manufactured by Kanto Chemical Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours. Next, MEK was removed by suction filtration, and the resulting powder was dried to prepare silver glycolate.
  • Hydroxypivalic acid silver salt 50 g of silver oxide (manufactured by Toyo Chemical Co., Ltd.), 25.48 g of hydroxypivalic acid (manufactured by Kanto Chemical Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours. Subsequently, MEK was removed by suction filtration, and the resulting powder was dried to prepare a hydroxypivalic acid silver salt.
  • Malonic acid silver salt 50 g of silver oxide (manufactured by Toyo Kagaku Kogyo Co., Ltd.), 11 g of malonic acid and 300 g of MEK were put into a ball mill and reacted by stirring at room temperature for 24 hours. Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare silver malonate.
  • Thermosetting resin bisphenol A type epoxy resin (EP-4100E, manufactured by ADEKA)
  • Thermosetting resin bisphenol F type epoxy resin (EP-4901E, manufactured by ADEKA)
  • -Thermosetting resin Urethane-modified epoxy resin (EPU-1395, manufactured by ADEKA)
  • Curing agent Boron trifluoride ethylamine (manufactured by Stella Chemifa)
  • Solvent Terpinel
  • the comparison between Examples 1 to 13 reveals that the volume resistivity after the wet heat resistance test can be further reduced when the difference between the thermal decomposition peak temperature and the thermal decomposition start temperature is 100 ° C. or more. Further, from the comparison with Examples 8, 14 and 15, when the content of the thermosetting resin (C) is 1.0 to 50 parts by mass with respect to 100 parts by mass of the copper powder (A), the formed electrode It has been found that the volume resistivity of etc. becomes lower.

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Abstract

The objective of the present invention is to provide: an electrically conductive composition that is able to form an electrode or the like having a low volume resistivity; and a solar cell that uses same in a collecting electrode. The electrically conductive composition has a copper powder (A), a fatty acid silver salt (B), and a thermosetting resin (C), wherein the difference between the pyrolysis start temperature and the pyrolysis peak temperature of the fatty acid silver salt (B) is at least 40°C, and the fatty acid silver salt (B) content is 20-100 parts by mass for every 100 parts by mass of the copper powder (A) when converted from the fatty acid silver salt (B) to the amount of generated silver.

Description

導電性組成物および太陽電池セルConductive composition and solar battery cell
　本発明は、導電性組成物およびそれを集電電極に用いた太陽電池セルに関する。 The present invention relates to a conductive composition and a solar battery cell using the same as a collecting electrode.
　従来、銀粒子などの導電性粒子に熱可塑性樹脂（例えば、アクリル樹脂、酢酸ビニル樹脂等）や熱硬化性樹脂（例えば、エポキシ樹脂、不飽和ポリエステル樹脂等）などからなるバインダー、有機溶剤、硬化剤、触媒等を添加し混合して得られる導電性ペースト（導電性組成物）を、基板（例えばシリコン基板、エポキシ樹脂基板など）上に所定のパターンとなるように印刷し、これらを加熱して電極や配線を形成し、太陽電池セルやプリント配線板を製造する方法が知られている。 Conventionally, conductive particles such as silver particles, binders made of thermoplastic resin (eg, acrylic resin, vinyl acetate resin, etc.) or thermosetting resin (eg, epoxy resin, unsaturated polyester resin, etc.), organic solvent, curing A conductive paste (conductive composition) obtained by adding and mixing an agent, a catalyst, etc., is printed on a substrate (for example, a silicon substrate, an epoxy resin substrate, etc.) in a predetermined pattern, and these are heated. There are known methods for forming electrodes and wiring and manufacturing solar cells and printed wiring boards.
　例えば、特許文献１には、「金属微粒子と分散媒とを含む金属微粒子インクペーストにおいて、該インクぺーストを、エポキシシランで表面処理したガラス基板に塗布した後、１８０℃で１０分間焼成して形成された膜厚１０μｍの薄膜の電気伝導度が１０４Ｓ／ｃｍ以上である金属微粒子インクペースト。」が記載され（［請求項１］）、有機金属化合物として「脂肪酸銀塩」を含有させることが記載され（［請求項２］［請求項６］［請求項８］）、金属微粒子として「銀及び／又は銅微粒子」を用いることが記載されている（［請求項１１］）。 For example, in Patent Document 1, “in a metal fine particle ink paste containing metal fine particles and a dispersion medium, the ink paste is applied to a glass substrate surface-treated with epoxy silane, and then baked at 180 ° C. for 10 minutes. The fine metal particle ink paste in which the electric conductivity of the formed thin film having a thickness of 10 μm is 10 4 S / cm or more ”is described ([Claim 1]), and includes“ fatty acid silver salt ”as an organometallic compound. ([Claim 2], [Claim 6], [Claim 8]) and “silver and / or copper fine particles” are used as the metal fine particles ([Claim 11]).
　また、本出願人により、特許文献２において、「銀粉（Ａ）と、脂肪酸銀塩（Ｂ）と、樹脂（Ｃ）と、溶媒（Ｄ）とを含有する導電性組成物であって、前記脂肪酸銀塩（Ｂ）が、カルボキシ銀塩基（－ＣＯＯＡｇ）を１個有し、かつ、水酸基（－ＯＨ）を１個または２個有する化合物であり、酸化銀の含有量が前記溶媒（Ｄ）１００質量部に対して１０質量部以下である導電性組成物。」が提案されている（［請求項１］）。 In addition, by the present applicant, in Patent Document 2, “a conductive composition containing silver powder (A), a fatty acid silver salt (B), a resin (C), and a solvent (D), The fatty acid silver salt (B) is a compound having one carboxy silver base (—COOAg) and one or two hydroxyl groups (—OH), and the content of silver oxide is the solvent (D) A conductive composition that is 10 parts by mass or less with respect to 100 parts by mass has been proposed ([Claim 1]).
特開２００８－１９８５９５号公報JP 2008-198595 A 特開２０１２－０２３０９５号公報JP 2012-023095 A
　しかしながら、特許文献１に記載された金属微粒子インクペーストにおいて金属微粒子として銅微粒子を採用した場合や、特許文献２に記載された導電性組成物の銀粉を銅粉に変更した場合には、銅粒子の少なくとも一部の表面が酸化されることにより、使用環境によっては形成される電極や配線（以下、「電極等」ともいう。）の体積抵抗率が高くなる場合があることが明らかとなった。 However, when the copper fine particles are employed as the metal fine particles in the metal fine particle ink paste described in Patent Document 1, or when the silver powder of the conductive composition described in Patent Document 2 is changed to copper powder, the copper particles It has been clarified that the volume resistivity of formed electrodes and wirings (hereinafter also referred to as “electrodes”) may be increased depending on the usage environment due to oxidation of at least a part of the surface of the electrode. .
　そこで、本発明は、体積抵抗率の低い電極等を形成することができる導電性組成物およびそれを集電電極に用いた太陽電池セルを提供することを課題とする。 Therefore, an object of the present invention is to provide a conductive composition capable of forming an electrode or the like having a low volume resistivity and a solar battery cell using the same as a collecting electrode.
　本発明者らは、上記課題を解決するため鋭意検討した結果、銅粉、脂肪酸銀塩および熱硬化性樹脂を含有する導電性組成物において、熱分解ピーク温度と熱分解開始温度との差が４０℃以上となる脂肪酸銀塩を特定量用いることにより、形成される電極等の体積抵抗率が低くなることを見出し、本発明を完成させた。
　すなわち、本発明者らは、以下の構成により上記課題が解決できることを見出した。 As a result of intensive studies to solve the above problems, the present inventors have found that in a conductive composition containing copper powder, a fatty acid silver salt and a thermosetting resin, there is a difference between the thermal decomposition peak temperature and the thermal decomposition start temperature. By using a specific amount of fatty acid silver salt at 40 ° C. or higher, it was found that the volume resistivity of the formed electrode or the like was lowered, and the present invention was completed.
That is, the present inventors have found that the above problem can be solved by the following configuration.
　（１）銅粉（Ａ）と、脂肪酸銀塩（Ｂ）と、熱硬化性樹脂（Ｃ）とを有する導電性組成物であって、
　上記脂肪酸銀塩（Ｂ）の熱分解ピーク温度と熱分解開始温度との差が４０℃以上であり、
　上記脂肪酸銀塩（Ｂ）の含有量が、上記脂肪酸銀塩（Ｂ）から生成する銀の量に換算して、上記銅粉（Ａ）１００質量部に対して２０～１００質量部である、導電性組成物。
　（２）上記熱硬化性樹脂（Ｃ）の含有量が、上記銅粉（Ａ）１００質量部に対して１～５０質量部である、上記（１）に記載の導電性組成物。 (1) A conductive composition comprising copper powder (A), a fatty acid silver salt (B), and a thermosetting resin (C),
The difference between the thermal decomposition peak temperature of the fatty acid silver salt (B) and the thermal decomposition start temperature is 40 ° C. or higher,
The content of the fatty acid silver salt (B) is 20 to 100 parts by mass with respect to 100 parts by mass of the copper powder (A) in terms of the amount of silver produced from the fatty acid silver salt (B). Conductive composition.
(2) The conductive composition according to (1), wherein the content of the thermosetting resin (C) is 1 to 50 parts by mass with respect to 100 parts by mass of the copper powder (A).
　（３）上記（１）または（２）に記載の導電性組成物を集電電極に用いた太陽電池セル。
　（４）上記集電電極の下地層として透明導電層を具備する上記（３）に記載の太陽電池セル。
　（５）上記（３）または（４）に記載の太陽電池セルを用いた太陽電池モジュール。 (3) A solar battery cell using the conductive composition according to (1) or (2) above as a collecting electrode.
(4) The solar battery cell according to (3), wherein a transparent conductive layer is provided as a base layer of the current collecting electrode.
(5) A solar cell module using the solar cell according to (3) or (4).
　以下に示すように、本発明によれば、体積抵抗率の低い電極等を形成することができる導電性組成物およびそれを集電電極に用いた太陽電池セルを提供することができる。
　また、本発明の導電性組成物を用いれば、低温～中温（４５０℃未満）、特に低温（１５０～３５０℃程度）での焼成であっても、体積抵抗率の低い電極等を形成することができるため、太陽電池セル（特に後述する第２の好適態様）への熱によるダメージを軽減できる効果も有し、非常に有用である。
　更に、本発明の導電性組成物を用いれば、酸化インジウムスズ（ＩＴＯ）やシリコンなどの耐熱性の高い材料のみならず、例えばＰＥＴフィルムなどの耐熱性の低い材料上にも電子回路、アンテナ等の回路を容易かつ短時間で作製することができるため非常に有用である。 As shown below, according to the present invention, it is possible to provide a conductive composition capable of forming an electrode or the like having a low volume resistivity, and a solar battery cell using the same as a collecting electrode.
Further, by using the conductive composition of the present invention, an electrode having a low volume resistivity can be formed even when firing at a low temperature to a medium temperature (less than 450 ° C.), particularly at a low temperature (about 150 to 350 ° C.). Therefore, the solar cell (especially the second preferred embodiment described later) has an effect of reducing damage caused by heat, which is very useful.
Furthermore, if the conductive composition of the present invention is used, an electronic circuit, an antenna, etc. not only on a material having high heat resistance such as indium tin oxide (ITO) or silicon but also on a material having low heat resistance such as PET film. This circuit is very useful because it can be manufactured easily and in a short time.
図１は、太陽電池セルの第１の好適態様を示す断面図である。FIG. 1 is a cross-sectional view showing a first preferred embodiment of a solar battery cell. 図２は、太陽電池セルの第２の好適態様を示す断面図である。FIG. 2 is a cross-sectional view showing a second preferred embodiment of the solar battery cell.
〔導電性組成物〕
　本発明の導電性組成物は、銅粉（Ａ）と、脂肪酸銀塩（Ｂ）と、熱硬化性樹脂（Ｃ）とを有する導電性組成物である。
　また、本発明の導電性組成物は、熱硬化性樹脂（Ｃ）としてエポキシ樹脂を用いた場合には、硬化剤（Ｄ）を含有してもよい。
　また、本発明の導電性組成物は、後述するように印刷性等の観点から、必要に応じて溶媒（Ｅ）を含有していてもよい。 [Conductive composition]
The conductive composition of the present invention is a conductive composition having copper powder (A), a fatty acid silver salt (B), and a thermosetting resin (C).
Moreover, the electrically conductive composition of this invention may contain a hardening | curing agent (D), when an epoxy resin is used as a thermosetting resin (C).
Moreover, the electrically conductive composition of this invention may contain the solvent (E) as needed from viewpoints of printability etc. so that it may mention later.
　本発明においては、熱分解ピーク温度と熱分解開始温度との差が４０℃以上となる脂肪酸銀塩（Ｂ）を特定量用いることにより、体積抵抗率の低い電極等を形成することができる導電性組成物となる。
　これは、詳細には明らかではないが、およそ以下のとおりと推測される。
　すなわち、熱分解ピーク温度と熱分解開始温度との差が４０℃以上の脂肪酸銀塩（Ｂ）を用いることにより、広い温度領域で脂肪酸銀塩から銀が生成し、その銀が銅粒子の表面を効率よく被覆することにより、銅粒子の表面の酸化を抑制することができたと考えられる。
　一方、熱分解ピーク温度と熱分解開始温度との差が４０℃未満の脂肪酸銀塩を用いた場合には、瞬時に銀が生成するため、銅粒子の表面を局所的にしか被覆することができず、酸化の抑制が不十分であったと考えられる。このことは、後述する比較例に示す結果からも推測される。 In the present invention, by using a specific amount of the fatty acid silver salt (B) having a difference between the thermal decomposition peak temperature and the thermal decomposition starting temperature of 40 ° C. or higher, an electrode having a low volume resistivity can be formed. Composition.
This is not clear in detail, but is estimated to be as follows.
That is, by using the fatty acid silver salt (B) having a difference between the thermal decomposition peak temperature and the thermal decomposition starting temperature of 40 ° C. or more, silver is produced from the fatty acid silver salt in a wide temperature range, and the silver is the surface of the copper particles. It is considered that the surface oxidation of the copper particles could be suppressed by efficiently covering the surface.
On the other hand, when a fatty acid silver salt having a difference between the pyrolysis peak temperature and the pyrolysis start temperature of less than 40 ° C. is used, silver is instantly formed, and therefore the surface of the copper particles can be coated only locally. It was not possible to suppress the oxidation. This is also inferred from the results shown in the comparative examples described later.
　以下に、銅粉（Ａ）、脂肪酸銀塩（Ｂ）および熱硬化性樹脂（Ｃ）ならびに所望により含有してもよい硬化剤（Ｄ）および溶媒（Ｅ）について詳述する。 Hereinafter, the copper powder (A), the fatty acid silver salt (B), the thermosetting resin (C), and the curing agent (D) and the solvent (E) which may be optionally contained will be described in detail.
 ＜銅粉（Ａ）＞
　本発明の導電性組成物で用いる銅粉（Ａ）は特に限定されず、従来公知の導電性ペーストで配合されているものを使用することができる。 <Copper powder (A)>
The copper powder (A) used in the conductive composition of the present invention is not particularly limited, and those blended with conventionally known conductive pastes can be used.
　上記銅粉（Ａ）は、印刷性が良好となり、体積抵抗率のより小さい電極等を形成することができる理由から、その平均粒子径は、１．０～２０μｍであるのが好ましく、２．０～１０μｍであるのがより好ましい。
　ここで、平均粒子径とは、粒子径の平均値をいい、レーザー回折・散乱式粒度分布測定装置を用いて測定し、粒子径基準を個数として演算された５０％体積累積径（Ｄ５０）をいう。なお、平均値を算出する基になる粒子径は、銅粉末の断面が楕円形である場合はその長径と短径の合計値を２で割った平均値をいい、正円形である場合はその直径をいう。 The copper powder (A) preferably has an average particle diameter of 1.0 to 20 μm because it has good printability and can form an electrode having a smaller volume resistivity. It is more preferably 0 to 10 μm.
Here, the average particle diameter means an average value of the particle diameters, and is measured by using a laser diffraction / scattering type particle size distribution measuring apparatus, and the 50% volume cumulative diameter (D50) calculated using the particle diameter standard as the number is used. Say. In addition, when the cross-section of the copper powder is elliptical, the particle diameter that is the basis for calculating the average value is the average value obtained by dividing the total value of the major axis and the minor axis by 2, and when it is a perfect circle, Refers to the diameter.
　本発明においては、このような銅粉（Ａ）として市販品を用いることができ、その具体例としては、Ｃｕ－ＨＷＱ（平均粒子径：３．０μｍ、福田金属箔粉工業社製）、ＦＣＣ－ＴＢＸ（平均粒子径：５．０５μｍ、福田金属箔粉工業社製）などが挙げられる。 In the present invention, a commercially available product can be used as such copper powder (A). Specific examples thereof include Cu-HWQ (average particle size: 3.0 μm, manufactured by Fukuda Metal Foil Powder Co., Ltd.), FCC. -TBX (average particle size: 5.05 μm, manufactured by Fukuda Metal Foil Powder Co., Ltd.)
 ＜脂肪酸銀塩（Ｂ）＞
　本発明の導電性組成物で用いる脂肪酸銀塩（Ｂ）は、その熱分解ピーク温度と熱分解開始温度との差が４０℃以上となる脂肪酸銀塩である。
　ここで、熱分解ピーク温度とは、示差熱－熱重量同時測定装置（ＴＧ－ＤＴＡ）を用い、空気中で昇温速度５℃／分にて室温から３００℃までの温度範囲で測定した際のＤＴＡ曲線に現れる発熱ピーク温度をいう。
　また、熱分解開始温度とは、示差熱－熱重量同時測定装置（ＴＧ－ＤＴＡ）を用い、空気中で昇温速度５℃／分にて室温から３００℃までの温度範囲で測定し、重量減少が開始した際の温度をいう。
　このような脂肪酸銀塩（Ｂ）を用いることにより、上述した通り、脂肪酸銀塩（Ｂ）の還元に由来する銀の生成が広い温度領域で生起し、上述した銅粉（Ａ）の表面を効率よく被覆することができると考えられる。
　また、脂肪酸銀塩（Ｂ）は、耐湿熱試験後の体積抵抗率の低い電極等を形成することができる理由から、熱分解ピーク温度と熱分解開始温度との差が、１００℃以上であるのが好ましく、１００～１３０℃であるのがより好ましい。これは、脂肪酸銀塩（Ｂ）の還元に由来する銀により、銅粉（Ａ）の表面を更に効率よく被覆することができたためと考えられる。 <Fatty acid silver salt (B)>
The fatty acid silver salt (B) used in the conductive composition of the present invention is a fatty acid silver salt in which the difference between the thermal decomposition peak temperature and the thermal decomposition start temperature is 40 ° C. or higher.
Here, the pyrolysis peak temperature is a value measured in the temperature range from room temperature to 300 ° C. in the air at a temperature rising rate of 5 ° C./min using a differential thermal-thermogravimetric simultaneous measurement device (TG-DTA). The exothermic peak temperature appearing in the DTA curve.
The pyrolysis start temperature is measured in the temperature range from room temperature to 300 ° C. in the air at a temperature rising rate of 5 ° C./min using a differential thermal-thermogravimetric simultaneous measurement device (TG-DTA). The temperature when the decrease starts.
By using such a fatty acid silver salt (B), as described above, the production of silver derived from the reduction of the fatty acid silver salt (B) occurs in a wide temperature range, and the surface of the copper powder (A) described above is obtained. It is thought that it can coat | cover efficiently.
In addition, the fatty acid silver salt (B) has a difference between the thermal decomposition peak temperature and the thermal decomposition starting temperature of 100 ° C. or more because it can form an electrode having a low volume resistivity after the wet heat test. The temperature is preferably 100 to 130 ° C. This is presumably because the surface of the copper powder (A) could be more efficiently coated with silver derived from the reduction of the fatty acid silver salt (B).
　上記脂肪酸銀塩（Ｂ）は、有機カルボン酸の銀塩のうち、熱分解ピーク温度と熱分解開始温度との差が４０℃以上であれば特に限定されず、例えば、特開２００８－１９８５９５号公報の［００６３］～［００６８］段落に記載された脂肪酸金属塩（特に３級脂肪酸銀塩）、特許第４４８２９３０号公報の［００３０］段落に記載された脂肪酸銀、特開２０１０－９２６８４号公報の［００４６］～［００５６］段落に記載された２級脂肪酸銀塩等を用いることができる。 The fatty acid silver salt (B) is not particularly limited as long as the difference between the thermal decomposition peak temperature and the thermal decomposition start temperature is 40 ° C. or higher among the silver salts of organic carboxylic acids. For example, JP-A-2008-198595 Fatty acid metal salts (particularly tertiary fatty acid silver salts) described in paragraphs [0063] to [0068] of the gazette, fatty acid silver described in paragraph [0030] of Japanese Patent No. 4482930, JP 2010-92684 A Secondary fatty acid silver salts described in the paragraphs [0046] to [0056] of the above can be used.
　上記脂肪酸銀塩（Ｂ）としては、具体的には、例えば、ステアリン酸銀塩、ｎ－酪酸銀塩、２－エチルヘキサン酸銀塩、２－メチルプロパン酸銀塩（別名：イソ酪酸銀塩）、ラウリン酸銀塩、２－エチル酪酸銀塩、ネオデカン酸銀塩、グルタル酸銀塩、アゼライン酸銀塩、１，２，３，４－ブタンテトラカルボン酸銀塩、４－シクロヘキセン－１，２－ジカルボン酸銀塩などが挙げられる。
　なお、これらの具体例の熱分解開始温度および熱分解ピーク温度は下記第１表に示す通りである。 Specific examples of the fatty acid silver salt (B) include, for example, silver stearate, silver n-butyrate, silver 2-ethylhexanoate, silver 2-methylpropanoate (also known as silver isobutyrate) ), Lauric acid silver salt, 2-ethylbutyric acid silver salt, neodecanoic acid silver salt, glutaric acid silver salt, azelaic acid silver salt, 1,2,3,4-butanetetracarboxylic acid silver salt, 4-cyclohexene-1, Examples include 2-dicarboxylic acid silver salt.
In addition, the thermal decomposition start temperature and thermal decomposition peak temperature of these specific examples are as shown in Table 1 below.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　本発明においては、上記脂肪酸銀塩（Ｂ）の含有量は、上記脂肪酸銀塩（Ｂ）から生成する銀の量に換算して、上記銅粉（Ａ）１００質量部に対して２０～１００質量部であり、３０～１００質量部であるのが好ましく、４０～１００質量部であるのがより好ましい。 In the present invention, the content of the fatty acid silver salt (B) is 20 to 100 with respect to 100 parts by mass of the copper powder (A) in terms of the amount of silver produced from the fatty acid silver salt (B). Parts by mass, preferably 30 to 100 parts by mass, and more preferably 40 to 100 parts by mass.
 ＜熱硬化性樹脂（Ｃ）＞
　本発明の導電性組成物で用いる熱硬化性樹脂（Ｃ）は特に限定されず、その具体例としては、エポキシ樹脂、ポリエステル樹脂、シリコーン樹脂、ウレタン樹脂等が挙げられ、これらを１種単独で用いてもよく、２種以上を併用してもよい。
　これらのうち、シリコン基板との密着力が強く、耐湿熱性が高いという理由から、エポキシ樹脂であるのが好ましい。 <Thermosetting resin (C)>
The thermosetting resin (C) used in the conductive composition of the present invention is not particularly limited, and specific examples thereof include an epoxy resin, a polyester resin, a silicone resin, a urethane resin, and the like. You may use, and may use 2 or more types together.
Among these, an epoxy resin is preferable because it has a strong adhesion to a silicon substrate and high heat and humidity resistance.
　（エポキシ樹脂）
　上記熱硬化性樹脂（Ｃ）の好適例としてのエポキシ樹脂は、１分子中に２個以上のオキシラン環（エポキシ基）を有する化合物からなる樹脂であれば特に限定されず、一般的に、エポキシ当量が９０～２０００のものである。
　このようなエポキシ樹脂としては、従来公知のエポキシ樹脂を用いることができる。
　具体的には、例えば、ビスフェノールＡ型、ビスフェノールＦ型、臭素化ビスフェノールＡ型、水添ビスフェノールＡ型、ビスフェノールＳ型、ビスフェノールＡＦ型、ビフェニル型等のビスフェニル基を有するエポキシ化合物や、ポリアルキレングリコール型、アルキレングリコール型のエポキシ化合物や、ナフタレン環を有するエポキシ化合物や、フルオレン基を有するエポキシ化合物等の二官能型のグリシジルエーテル系エポキシ樹脂；
　フェノールノボラック型、オルソクレゾールノボラック型、トリスヒドロキシフェニルメタン型、テトラフェニロールエタン型等の多官能型のグリシジルエーテル系エポキシ樹脂；
　ダイマー酸等の合成脂肪酸のグリシジルエステル系エポキシ樹脂；
　Ｎ，Ｎ，Ｎ′，Ｎ′－テトラグリシジルジアミノジフェニルメタン（ＴＧＤＤＭ）、テトラグリシジルジアミノジフェニルスルホン（ＴＧＤＤＳ）、テトラグリシジル－ｍ－キシリレンジアミン（ＴＧＭＸＤＡ）、トリグリシジル－ｐ－アミノフェノール、トリグリシジル－ｍ－アミノフェノール、Ｎ，Ｎ－ジグリシジルアニリン、テトラグリシジル１，３－ビスアミノメチルシクロヘキサン（ＴＧ１，３－ＢＡＣ）、トリグリシジルイソシアヌレート（ＴＧＩＣ）等のグリシジルアミン系エポキシ樹脂；
　トリシクロ〔５，２，１，０2,6〕デカン環を有するエポキシ化合物、具体的には、例えば、ジシクロペンタジエンとメタクレゾール等のクレゾール類またはフェノール類を重合させた後、エピクロルヒドリンを反応させる公知の製造方法によって得ることができるエポキシ化合物；
　脂環型エポキシ樹脂；東レチオコール社製のフレップ１０に代表されるエポキシ樹脂主鎖に硫黄原子を有するエポキシ樹脂；ウレタン結合を有するウレタン変性エポキシ樹脂；ポリブタジエン、液状ポリアクリロニトリル－ブタジエンゴムまたはアクリロニトリルブタジエンゴム（ＮＢＲ）を含有するゴム変性エポキシ樹脂等が挙げられる。 (Epoxy resin)
The epoxy resin as a suitable example of the thermosetting resin (C) is not particularly limited as long as it is a resin composed of a compound having two or more oxirane rings (epoxy groups) in one molecule. The equivalent is 90-2000.
A conventionally well-known epoxy resin can be used as such an epoxy resin.
Specifically, for example, epoxy compounds having a bisphenyl group such as bisphenol A type, bisphenol F type, brominated bisphenol A type, hydrogenated bisphenol A type, bisphenol S type, bisphenol AF type, biphenyl type, and polyalkylene Bifunctional glycidyl ether type epoxy resins such as glycol type, alkylene glycol type epoxy compounds, epoxy compounds having a naphthalene ring, and epoxy compounds having a fluorene group;
Polyfunctional glycidyl ether type epoxy resins such as phenol novolac type, orthocresol novolak type, trishydroxyphenylmethane type, tetraphenylolethane type;
Glycidyl ester epoxy resins of synthetic fatty acids such as dimer acid;
N, N, N ′, N′-tetraglycidyldiaminodiphenylmethane (TGDDM), tetraglycidyldiaminodiphenylsulfone (TGDDS), tetraglycidyl-m-xylylenediamine (TGMXDA), triglycidyl-p-aminophenol, triglycidyl- Glycidylamine epoxy resins such as m-aminophenol, N, N-diglycidylaniline, tetraglycidyl 1,3-bisaminomethylcyclohexane (TG1,3-BAC), triglycidyl isocyanurate (TGIC);
Tricyclo [5,2,1,0 2,6] epoxy compound having a decane ring, specifically, for example, after polymerizing the cresols or phenols such as dicyclopentadiene and cresol are reacted with epichlorohydrin Epoxy compounds obtainable by known production methods;
An alicyclic epoxy resin; an epoxy resin represented by Toray Rethiokol's Flep 10 epoxy resin having a sulfur atom in the main chain; a urethane-modified epoxy resin having a urethane bond; polybutadiene, liquid polyacrylonitrile-butadiene rubber or acrylonitrile butadiene rubber Examples thereof include a rubber-modified epoxy resin containing (NBR).
　これらのエポキシ樹脂は、１種単独で用いても、２種以上を併用してもよい。
　また、これらのうち、硬化性、耐熱性、耐久性およびコストの観点から、ビスフェノールＡ型エポキシ樹脂、ビスフェノールＦ型エポキシ樹脂であるのが好ましい。 These epoxy resins may be used alone or in combination of two or more.
Of these, bisphenol A type epoxy resins and bisphenol F type epoxy resins are preferable from the viewpoints of curability, heat resistance, durability, and cost.
　本発明においては、上記熱硬化性樹脂（Ｃ）の含有量は、形成される電極等の体積抵抗率がより低くなる理由から、上記銅粉（Ａ）１００質量部に対して１．０～５０質量部であるのが好ましく、２～２５質量部であるのがより好ましい。 In the present invention, the content of the thermosetting resin (C) is 1.0 to 100 parts by mass with respect to 100 parts by mass of the copper powder (A) because the volume resistivity of the formed electrode or the like is lower. The amount is preferably 50 parts by mass, more preferably 2 to 25 parts by mass.
 ＜硬化剤（Ｄ）＞
　上記熱硬化性樹脂（Ｃ）としてエポキシ樹脂を用いる場合、本発明の導電性組成物は、三フッ化ホウ素とアミン化合物との錯体からなる硬化剤（Ｄ）を含有するのが好ましい。
　三フッ化ホウ素とアミン化合物との錯体としては、三フッ化ホウ素と脂肪族アミン（脂肪族第１級アミン、脂肪族第２級アミン、脂肪族第３級アミン）との錯体、三フッ化ホウ素と脂環式アミンとの錯体、三フッ化ホウ素と芳香族アミンとの錯体、三フッ化ホウ素と複素環アミンとの錯体などが挙げられる。上記複素環アミンは、脂環式の複素環アミン（以下、脂環式複素環アミンともいう）であっても、芳香族の複素環アミン（以下、芳香族複素環アミンともいう）であってもよい。
　脂肪族第１級アミンの具体例としては、メチルアミン、エチルアミン、ｎ－プロピルアミン、ｉｓｏ－プロピルアミン、ｎ－ブチルアミン、ｉｓｏ－ブチルアミン、ｓｅｃ－ブチルアミン、ｎ－ヘキシルアミン、ｎ－オクチルアミン、２－エチルヘキシルアミン、ラウリルアミン等が挙げられる。脂肪族第２級アミンの具体例としては、ジメチルアミン、ジエチルアミン、メチルエチルアミン、メチルプロピルアミン、ジ－ｉｓｏ－プロピルアミン、ジ－ｎ－プロピルアミン、エチルプロピルアミン、ジ－ｎ－ブチルアミン、ジ－ｉｓｏ－ブチルアミン、ジプロペニルアミン、クロロブチルプロピルアミン、ジ（クロロブチル）アミン、ジ（ブロモエチル）アミン等が挙げられる。脂肪族第３級アミンの具体例としては、トリメチルアミン、トリエチルアミン、トリブチルアミン、トリエタノールアミン等が挙げられる。脂環式アミンの具体例としては、シクロヘキシルアミン等が挙げられる。芳香族アミンとしては、ベンジルアミン等が挙げられる。脂環式複素環アミンの具体例としては、ピロリジン、ピペリジン、２－ピペコリン、３－ピペコリン、４－ピペコリン、２，４－ルペチジン、２，６－ルペチジン、３，５－ルペチジン、ピペラジン、ホモピペラジン、Ｎ－メチルピペラジン、Ｎ－エチルピペラジン、Ｎ－プロピルピペラジン、Ｎ－メチルホモピペラジン、Ｎ－アセチルピペラジン、１－（クロロフェニル）ピペラジン、Ｎ－アミノエチルピペリジン、Ｎ－アミノプロピルピペリジン、Ｎ－アミノエチルピペラジン、Ｎ－アミノプロピルピペラジン、モルホリン、Ｎ－アミノエチルモルホリン、Ｎ－アミノプロピルモルホリン、Ｎ－アミノプロピル－２－ピペコリン、Ｎ－アミノプロピル－４－ピペコリン、１，４－ビス（アミノプロピル）ピペラジン、トリエチレンジアミン、２－メチルトリエチエレンジアミン等が挙げられる。芳香族複素環アミンの具体例としては、ピリジン、ピロール、イミダゾール、ピリダジン、ピリミジン、キノリン、トリアジン、テトラジン、イソキノリン、キナゾリン、ナフチリジン、プテリジン、アクリジン、フェナジン等が挙げられる。 <Curing agent (D)>
When using an epoxy resin as the thermosetting resin (C), the conductive composition of the present invention preferably contains a curing agent (D) composed of a complex of boron trifluoride and an amine compound.
As a complex of boron trifluoride and an amine compound, a complex of boron trifluoride and an aliphatic amine (aliphatic primary amine, aliphatic secondary amine, aliphatic tertiary amine), trifluoride Examples thereof include a complex of boron and an alicyclic amine, a complex of boron trifluoride and an aromatic amine, a complex of boron trifluoride and a heterocyclic amine, and the like. The heterocyclic amine may be an alicyclic heterocyclic amine (hereinafter also referred to as an alicyclic heterocyclic amine) or an aromatic heterocyclic amine (hereinafter also referred to as an aromatic heterocyclic amine). Also good.
Specific examples of the aliphatic primary amine include methylamine, ethylamine, n-propylamine, iso-propylamine, n-butylamine, iso-butylamine, sec-butylamine, n-hexylamine, n-octylamine, 2 -Ethylhexylamine, laurylamine and the like. Specific examples of the aliphatic secondary amine include dimethylamine, diethylamine, methylethylamine, methylpropylamine, di-iso-propylamine, di-n-propylamine, ethylpropylamine, di-n-butylamine, di- Examples include iso-butylamine, dipropenylamine, chlorobutylpropylamine, di (chlorobutyl) amine, di (bromoethyl) amine and the like. Specific examples of the aliphatic tertiary amine include trimethylamine, triethylamine, tributylamine, triethanolamine and the like. Specific examples of the alicyclic amine include cyclohexylamine. Examples of aromatic amines include benzylamine. Specific examples of the alicyclic heterocyclic amine include pyrrolidine, piperidine, 2-pipecoline, 3-pipecoline, 4-pipecoline, 2,4-lupetidine, 2,6-lupetidine, 3,5-lupetidine, piperazine, and homopiperazine. N-methylpiperazine, N-ethylpiperazine, N-propylpiperazine, N-methylhomopiperazine, N-acetylpiperazine, 1- (chlorophenyl) piperazine, N-aminoethylpiperidine, N-aminopropylpiperidine, N-aminoethyl Piperazine, N-aminopropylpiperazine, morpholine, N-aminoethylmorpholine, N-aminopropylmorpholine, N-aminopropyl-2-pipecholine, N-aminopropyl-4-pipecholine, 1,4-bis (aminopropyl) piperazine , Triethylenediamine , 2-methyl-triethylene Chie diamine and the like. Specific examples of the aromatic heterocyclic amine include pyridine, pyrrole, imidazole, pyridazine, pyrimidine, quinoline, triazine, tetrazine, isoquinoline, quinazoline, naphthyridine, pteridine, acridine, phenazine and the like.
　上記硬化剤（Ｄ）は、形成される電極等の体積抵抗率がより低くなる理由から、三フッ化ホウ素ピペリジン、三フッ化ホウ素エチルアミンおよび三フッ化ホウ素トリエタノールアミンからなる群より選択される錯体であることが好ましい。 The curing agent (D) is selected from the group consisting of boron trifluoride piperidine, boron trifluoride ethylamine, and boron trifluoride triethanolamine because the volume resistivity of the formed electrode or the like is lower. A complex is preferred.
　上記硬化剤（Ｄ）の含有量は、形成される電極等の体積抵抗率がより低くなる理由から、上記エポキシ樹脂１００質量部に対して、１～１５質量部であることが好ましく、１～１０質量部であることがより好ましい。 The content of the curing agent (D) is preferably 1 to 15 parts by mass with respect to 100 parts by mass of the epoxy resin, because the volume resistivity of the formed electrode or the like becomes lower. It is more preferable that it is 10 mass parts.
 ＜溶媒（Ｅ）＞
　本発明の導電性組成物は、印刷性等の作業性の観点から、溶媒（Ｅ）を含有するのが好ましい。
　上記溶媒（Ｅ）は、本発明の導電性組成物を基材上に塗布することができるものであれば特に限定されず、その具体例としては、ブチルカルビトール、メチルエチルケトン、イソホロン、α－テルピネオール等が挙げられ、これらを１種単独で用いても２種以上を併用してもよい。 <Solvent (E)>
The conductive composition of the present invention preferably contains a solvent (E) from the viewpoint of workability such as printability.
The solvent (E) is not particularly limited as long as it can apply the conductive composition of the present invention onto a substrate. Specific examples thereof include butyl carbitol, methyl ethyl ketone, isophorone, α-terpineol. These may be used, and these may be used alone or in combination of two or more.
 ＜添加剤＞
　本発明の導電性組成物は、必要に応じて、還元剤等の添加剤を含有していてもよい。
　上記還元剤としては、具体的には、例えば、エチレングリコール類等が挙げられる。 <Additives>
The electrically conductive composition of this invention may contain additives, such as a reducing agent, as needed.
Specific examples of the reducing agent include ethylene glycols.
 ＜導電性組成物の製造方法＞
　本発明の導電性組成物の製造方法は特に限定されず、上記銅粉（Ａ）、上記脂肪酸銀塩（Ｂ）および上記熱硬化性樹脂（Ｃ）ならびに所望により含有してもよい上記硬化剤（Ｄ）、上記溶媒（Ｅ）および添加剤等を、ロール、ニーダー、押出し機、万能かくはん機等により混合する方法が挙げられる。 <Method for producing conductive composition>
The manufacturing method of the electrically conductive composition of this invention is not specifically limited, The said copper powder (A), the said fatty acid silver salt (B), the said thermosetting resin (C), and the said hardening | curing agent which may be contained if desired. (D), the method of mixing the said solvent (E), an additive, etc. with a roll, a kneader, an extruder, a universal stirrer etc. is mentioned.
〔太陽電池セル〕
　本発明の太陽電池セルは、上述した本発明の導電性組成物を集電電極に用いた太陽電池セルである。 [Solar cells]
The solar battery cell of the present invention is a solar battery cell using the above-described conductive composition of the present invention as a collecting electrode.
 ＜太陽電池セルの第１の好適な態様＞
　本発明の太陽電池セルの第１の好適な態様としては、受光面側の表面電極、半導体基板および裏面電極を具備し、上記表面電極および／または上記裏面電極が、上述した本発明の導電性組成物を用いて形成される太陽電池セルが挙げられる。
　以下に、本発明の太陽電池セルの第１の好適な態様について図１を用いて説明する。 <First preferred embodiment of solar cell>
As a 1st suitable aspect of the photovoltaic cell of this invention, it comprises the surface electrode by the side of a light-receiving surface, a semiconductor substrate, and a back electrode, The said surface electrode and / or the said back electrode are the electroconductivity of this invention mentioned above. A solar battery cell formed using the composition can be mentioned.
Below, the 1st suitable aspect of the photovoltaic cell of this invention is demonstrated using FIG.
　図１に示すように、太陽電池セル１は、受光面側の表面電極４と、ｐ層５およびｎ層２が接合したｐｎ接合シリコン基板７と、裏面電極６とを具備するものである。
　また、図１に示すように、太陽電池セル１は、反射率低減のため、例えば、ウエハ表面にエッチングを施して、ピラミッド状のテクスチャを形成し、反射防止膜３を具備するのが好ましい。
　以下に、本発明の太陽電池セルの第１の好適な態様が具備する上記表面電極、裏面電極およびシリコン基板並びに具備していてもよい上記反射防止膜について詳述する。 As shown in FIG. 1, the solar cell 1 includes a surface electrode 4 on the light receiving surface side, a pn junction silicon substrate 7 in which a p layer 5 and an n layer 2 are joined, and a back electrode 6.
As shown in FIG. 1, the solar battery cell 1 is preferably provided with an antireflection film 3, for example, by etching the wafer surface to form a pyramidal texture in order to reduce reflectivity.
Below, the said surface electrode, back surface electrode, silicon substrate which the 1st suitable aspect of the photovoltaic cell of this invention comprises, and the said antireflection film which may be equipped are explained in full detail.
　（表面電極／裏面電極）
　表面電極および裏面電極は、いずれか一方または両方が本発明の導電性組成物を用いて形成されていれば、電極の配置（ピッチ）、形状、高さ、幅等は特に限定されない。なお、電極の高さは、通常、数～数十μｍに設計されるが、本発明の導電性組成物を用いて形成した電極の断面の高さと幅の比率（高さ／幅）（以下、「アスペクト比」という。）を大きく（例えば、０．４程度以上）調整することが可能となる。
　ここで、表面電極および裏面電極は、図１に示すように、通常、複数個有するものであるが、例えば、複数の表面電極の一部のみが本発明の導電性組成物で形成されたものであってもよく、複数の表面電極の一部と複数の裏面電極の一部が本発明の導電性組成物で形成されたものであってもよい。 (Front electrode / Back electrode)
As long as any one or both of the front electrode and the back electrode are formed using the conductive composition of the present invention, the arrangement (pitch), shape, height, width and the like of the electrode are not particularly limited. The height of the electrode is usually designed to be several to several tens of μm, but the ratio of the height and width of the cross section of the electrode formed using the conductive composition of the present invention (height / width) (below) , “Aspect ratio”) can be adjusted to a large value (for example, about 0.4 or more).
Here, as shown in FIG. 1, the front surface electrode and the back surface electrode usually have a plurality, but, for example, only a part of the plurality of surface electrodes is formed of the conductive composition of the present invention. Alternatively, part of the plurality of front surface electrodes and part of the plurality of back surface electrodes may be formed of the conductive composition of the present invention.
　（反射防止膜）
　反射防止膜は、受光面の表面電極が形成されていない部分に形成される膜（膜厚：０．０５～０．１μｍ程度）であって、例えば、シリコン酸化膜、シリコン窒化膜、酸化チタン膜、これらの積層膜等から構成されるものである。 (Antireflection film)
The antireflection film is a film (film thickness: about 0.05 to 0.1 μm) formed on a portion of the light receiving surface where the surface electrode is not formed. For example, a silicon oxide film, a silicon nitride film, a titanium oxide It is comprised from a film | membrane, these laminated films, etc.
　また、上記シリコン基板はｐｎ接合を有するが、これは、第１導電型の半導体基板の表面側に第２導電型の受光面不純物拡散領域が形成されていることを意味する。なお、第１導電型がｎ型の場合には、第２導電型はｐ型であり、第１導電型がｐ型の場合には、第２導電型はｎ型である。
　ここで、ｐ型を与える不純物としては、ホウ素、アルミニウム等が挙げられ、ｎ型を与える不純物としては、リン、砒素などが挙げられる。 The silicon substrate has a pn junction, which means that a second conductivity type light-receiving surface impurity diffusion region is formed on the surface side of the first conductivity type semiconductor substrate. When the first conductivity type is n-type, the second conductivity type is p-type. When the first conductivity type is p-type, the second conductivity type is n-type.
Here, examples of the impurity imparting p-type include boron and aluminum, and examples of the impurity imparting n-type include phosphorus and arsenic.
　（シリコン基板）
　シリコン基板は特に限定されず、太陽電池を形成するための公知のシリコン基板（板厚：８０～４５０μｍ程度）を用いることができ、また、単結晶または多結晶のいずれのシリコン基板であってもよい。 (Silicon substrate)
The silicon substrate is not particularly limited, and a known silicon substrate (plate thickness: about 80 to 450 μm) for forming a solar cell can be used, and either a monocrystalline or polycrystalline silicon substrate can be used. Good.
　本発明の太陽電池セルの第１の好適な態様において、太陽電池セルは、表面電極および／または裏面電極が本発明の導電性組成物を用いて形成されているため、電極のアスペクト比を大きくし易く、受光により発生した起電力を電流として効率良く取り出すことができる。 In the first preferred embodiment of the solar battery cell of the present invention, the solar battery cell has a large electrode aspect ratio because the surface electrode and / or the back electrode is formed using the conductive composition of the present invention. The electromotive force generated by light reception can be efficiently taken out as a current.
　なお、上述した本発明の導電性組成物は全裏面電極型（いわゆるバックコンタクト型）太陽電池の裏面電極の形成にも適用することができるため、全裏面電極型の太陽電池にも適用することができる。 In addition, since the conductive composition of the present invention described above can also be applied to the formation of the back electrode of an all-back electrode type (so-called back contact type) solar cell, it can also be applied to an all-back electrode type solar cell. Can do.
 ＜太陽電池セル（第１の好適な態様）の製造方法＞
　上記太陽電池セル（第１の好適な態様）の製造方法は特に限定されないが、本発明の導電性組成物をシリコン基板上に塗布して配線を形成する配線形成工程と、形成された配線を熱処理して電極（表面電極および／または裏面電極）を形成する熱処理工程とを有する方法が挙げられる。
　なお、太陽電池セルが反射防止層を具備する場合、反射防止膜は、プラズマＣＶＤ法等の公知の方法により形成することができる。
　以下に、配線形成工程、熱処理工程について詳述する。 <The manufacturing method of a photovoltaic cell (1st suitable aspect)>
Although the manufacturing method of the said photovoltaic cell (1st suitable aspect) is not specifically limited, The wiring formation process which apply | coats the electrically conductive composition of this invention on a silicon substrate, and forms wiring, and the formed wiring And a heat treatment step of forming an electrode (front electrode and / or back electrode) by heat treatment.
In the case where the solar battery cell includes an antireflection layer, the antireflection film can be formed by a known method such as a plasma CVD method.
Below, a wiring formation process and a heat treatment process are explained in full detail.
　（配線形成工程）
　上記配線形成工程は、本発明の導電性組成物をシリコン基板上に塗布して配線を形成する工程である。
　ここで、塗布方法としては、具体的には、例えば、インクジェット、スクリーン印刷、グラビア印刷、オフセット印刷、凸版印刷等が挙げられる。 (Wiring formation process)
The wiring formation step is a step of forming a wiring by applying the conductive composition of the present invention on a silicon substrate.
Here, specific examples of the coating method include inkjet, screen printing, gravure printing, offset printing, letterpress printing, and the like.
　（熱処理工程）
　上記熱処理工程は、上記配線形成工程で形成された塗膜を熱処理して導電性の配線（電極）を形成する工程である。
　配線を熱処理することにより、脂肪酸銀塩（Ｂ）から分解される銀が溶融する際に銅粉（Ａ）の表面を被覆しつつ連結し、電極が形成される。 (Heat treatment process)
The heat treatment step is a step of forming a conductive wiring (electrode) by heat-treating the coating film formed in the wiring forming step.
By heat-treating the wiring, when the silver decomposed from the fatty acid silver salt (B) melts, the wiring is connected while covering the surface of the copper powder (A), thereby forming an electrode.
　上記熱処理は特に限定されないが、１５０～３５０℃の比較的低い温度で、数秒～数十分間、加熱（焼成）する処理であるのが好ましい。温度および時間がこの範囲であると、シリコン基板上に反射防止膜を形成した場合であっても、容易に電極を形成することができる。
　また、本発明の太陽電池セルの第１の好適な態様においては、本発明の導電性組成物を用いているため、１５０～３５０℃の比較的低い温度であっても、良好な熱処理（焼成）を施すことができる。
　本発明においては、上記配線形成工程で形成された配線は、紫外線または赤外線の照射でも電極を形成することができるため、上記熱処理工程は、紫外線または赤外線の照射によるものであってもよい。 The heat treatment is not particularly limited, but is preferably a treatment in which heating (firing) is performed at a relatively low temperature of 150 to 350 ° C. for several seconds to several tens of minutes. When the temperature and time are within this range, an electrode can be easily formed even when an antireflection film is formed on a silicon substrate.
Further, in the first preferred embodiment of the solar battery cell of the present invention, since the conductive composition of the present invention is used, good heat treatment (firing) can be achieved even at a relatively low temperature of 150 to 350 ° C. ) Can be applied.
In the present invention, since the wiring formed in the wiring formation step can form electrodes even by irradiation with ultraviolet rays or infrared rays, the heat treatment step may be performed by irradiation with ultraviolet rays or infrared rays.
 ＜太陽電池セルの第２の好適な態様＞
　本発明の太陽電池セルの第２の好適な態様としては、ｎ型単結晶シリコン基板を中心にその上下にアモルファスシリコン層および透明導電層（例えば、ＴＣＯ）を具備し、上記透明導電層を下地層として、上記透明導電層上に上述した本発明の導電性組成物を用いて集電電極を形成した太陽電池（例えばヘテロ接合型太陽電池）セルが挙げられる。上記太陽電池セル（第２の好適な態様）は、単結晶シリコンとアモルファスシリコンとをハイブリッドした太陽電池セルであり、高い変換効率を示す。
　以下に、本発明の太陽電池セルの第２の好適な態様について図２を用いて説明する。 <The 2nd suitable aspect of a photovoltaic cell>
As a second preferred embodiment of the solar battery cell of the present invention, an amorphous silicon layer and a transparent conductive layer (for example, TCO) are provided above and below an n-type single crystal silicon substrate, and the transparent conductive layer is disposed below. Examples of the base layer include a solar cell (for example, a heterojunction solar cell) cell in which a collecting electrode is formed on the transparent conductive layer using the conductive composition of the present invention described above. The solar battery cell (second preferred embodiment) is a solar battery cell in which single crystal silicon and amorphous silicon are hybridized and exhibits high conversion efficiency.
Below, the 2nd suitable aspect of the photovoltaic cell of this invention is demonstrated using FIG.
　図２に示すように、太陽電池セル１００は、ｎ型単結晶シリコン基板１１を中心に、その上下にｉ型アモルファスシリコン層１２ａおよび１２ｂ、並びに、ｐ型アモルファスシリコン層１３ａおよびｎ型アモルファスシリコン層１３ｂ、並びに、透明導電層１４ａおよび１４ｂ、並びに、上述した本発明の導電性組成物を用いて形成した集電電極１５ａおよび１５ｂを具備する。 As shown in FIG. 2, the solar battery cell 100 has an n-type single crystal silicon substrate 11 as a center, i-type amorphous silicon layers 12 a and 12 b, and p-type amorphous silicon layers 13 a and n-type amorphous silicon layers above and below it. 13b, transparent conductive layers 14a and 14b, and current collecting electrodes 15a and 15b formed using the above-described conductive composition of the present invention.
　上記ｎ型単結晶シリコン基板は、ｎ型を与える不純物がドープされた単結晶シリコン層である。ｎ型を与える不純物は上述のとおりである。
　上記ｉ型アモルファスシリコン層は、ドープされていないアモルファスシリコン層である。
　上記ｐ型アモルファスシリコンは、ｐ型を与える不純物がドープされたアモルファスシリコン層である。ｐ型を与える不純物は上述のとおりである。
　上記ｎ型アモルファスシリコンは、ｎ型を与える不純物がドープされたアモルファスシリコン層である。ｎ型を与える不純物は上述のとおりである。
　上記集電電極は、上述した本発明の導電性組成物を用いて形成された集電電極である。集電電極の具体的な態様は上述した表面電極または裏面電極と同じである。 The n-type single crystal silicon substrate is a single crystal silicon layer doped with an n-type impurity. Impurities that give n-type are as described above.
The i-type amorphous silicon layer is an undoped amorphous silicon layer.
The p-type amorphous silicon is an amorphous silicon layer doped with an impurity imparting p-type. Impurities that give p-type are as described above.
The n-type amorphous silicon is an amorphous silicon layer doped with an n-type impurity. Impurities that give n-type are as described above.
The said collector electrode is a collector electrode formed using the electrically conductive composition of this invention mentioned above. A specific aspect of the current collecting electrode is the same as that of the front surface electrode or the back surface electrode described above.
　（透明導電層）
　上記透明導電層の材料の具体例としては、酸化亜鉛、酸化スズ、酸化インジウム、酸化チタンなどの単一金属酸化物、酸化インジウムスズ（ＩＴＯ）、酸化インジウム亜鉛、酸化インジウムチタン、酸化スズカドミウム、などの多種金属酸化物、ガリウム添加酸化亜鉛、アルミニウム添加酸化亜鉛、硼素添加酸化亜鉛、チタン添加酸化亜鉛、チタン添加酸化インジウム、ジルコニウム添加酸化インジウム、フッ素添加酸化スズなどのドーピング型金属酸化物などが挙げられる。 (Transparent conductive layer)
Specific examples of the material for the transparent conductive layer include single metal oxides such as zinc oxide, tin oxide, indium oxide, and titanium oxide, indium tin oxide (ITO), indium zinc oxide, indium titanium oxide, tin cadmium oxide, Various metal oxides such as gallium-doped zinc oxide, aluminum-doped zinc oxide, boron-doped zinc oxide, titanium-doped zinc oxide, titanium-doped indium oxide, zirconium-doped indium oxide, and fluorine-doped tin oxide. Can be mentioned.
 ＜太陽電池セル（第２の好適な態様）の製造方法＞
　上記太陽電池セル（第２の好適な態様）の製造方法は特に限定されないが、例えば、特開２０１０－３４１６２号公報に記載の方法などで製造することができる。
　具体的には、ｎ型単結晶シリコン基板１１の片方の主面上に、ＰＥＣＶＤ（ｐｌａｓｍａ　ｅｎｈａｎｃｅｄ　ｃｈｅｍｉｃａｌ　ｖａｐｏｒ　ｄｅｐｏｓｉｔｉｏｎ）法などによって、ｉ型アモルファスシリコン層１２ａを形成する。さらに、形成したｉ型アモルファスシリコン層１２ａ上にＰＥＣＶＤ法などによってｐ型アモルファスシリコン層１３ａを形成する。
　次に、ｎ型単結晶シリコン基板１１のもう一方の主面上に、ＰＥＣＶＤ法などによって、ｉ型アモルファスシリコン層１２ｂを形成する。さらに、形成したｉ型アモルファスシリコン層１２ｂ上にＰＥＣＶＤ法などによってｎ型アモルファスシリコン層１３ｂを形成する。
　次に、スパッタ法などによって、ｐ型アモルファスシリコン層１３ａ上およびｎ型アモルファスシリコン層１３ｂ上にＩＴＯなどの透明導電層１４ａおよび１４ｂを形成する。
　次に、形成した透明導電層１４ａおよび１４ｂ上に本発明の導電性組成物を塗布して配線を形成し、さらに、形成した配線を熱処理することで集電電極１５ａおよび１５ｂを形成する。
　配線を形成する方法は、上述した太陽電池セル（第１の好適な態様）の配線形成工程に記載した方法と同じである。
　配線を熱処理する方法は、上述した太陽電池セル（第１の好適な態様）の熱処理工程に記載した方法と同じであるが、熱処理温度（焼成温度）は１５０～２００℃であることが好ましい。 <The manufacturing method of a photovoltaic cell (2nd suitable aspect)>
The method for producing the solar battery cell (second preferred embodiment) is not particularly limited, and can be produced by, for example, the method described in JP 2010-34162 A.
Specifically, the i-type amorphous silicon layer 12a is formed on one main surface of the n-type single crystal silicon substrate 11 by a PECVD (plasma enhanced chemical vapor deposition) method or the like. Further, a p-type amorphous silicon layer 13a is formed on the formed i-type amorphous silicon layer 12a by PECVD or the like.
Next, an i-type amorphous silicon layer 12b is formed on the other main surface of the n-type single crystal silicon substrate 11 by PECVD or the like. Further, an n-type amorphous silicon layer 13b is formed on the formed i-type amorphous silicon layer 12b by PECVD or the like.
Next, transparent conductive layers 14a and 14b such as ITO are formed on the p-type amorphous silicon layer 13a and the n-type amorphous silicon layer 13b by sputtering or the like.
Next, the conductive composition of the present invention is applied on the formed transparent conductive layers 14a and 14b to form wirings, and the formed wirings are heat-treated to form current collecting electrodes 15a and 15b.
The method for forming the wiring is the same as the method described in the wiring formation step of the above-described solar battery cell (first preferred embodiment).
The method of heat-treating the wiring is the same as the method described in the heat treatment step of the above-described solar battery cell (first preferred embodiment), but the heat treatment temperature (firing temperature) is preferably 150 to 200 ° C.
　以下、実施例を用いて、本発明の導電性組成物について詳細に説明する。ただし、本発明はこれに限定されるものではない。 Hereinafter, the conductive composition of the present invention will be described in detail using examples. However, the present invention is not limited to this.
　（実施例１～１７、比較例１～６）
　下記第２表に示す銅粉等を下記第２表中に示す組成比（質量部）となるように配合し、これらを混合することにより導電性組成物を調製した。 (Examples 1 to 17, Comparative Examples 1 to 6)
The copper powder etc. which are shown in the following 2nd table | surface were mix | blended so that it might become a composition ratio (mass part) shown in the following 2nd table | surface, and the electroconductive composition was prepared by mixing these.
　＜体積抵抗率（比抵抗）＞
　調製した各導電性組成物を、ＴＣＯであるＩＴＯ蒸着ガラス基板上に、スクリーン印刷で塗布して、２５ｍｍ×２５ｍｍのベタ塗りであるテストパターンを形成した。オーブンにて２００℃で３０分間乾燥し、導電性被膜を作製した。
　作製した各導電性被膜について、作製直後（初期）、および、８５℃、８５％湿度で５００時間放置した後（耐湿熱試験後）の体積抵抗率を、抵抗率計（ロレスターＧＰ、三菱化学社製）を用いた４端子４探針法により測定した。結果を下記第２表に示す。 <Volume resistivity (specific resistance)>
Each prepared electrically conductive composition was apply | coated by screen printing on the ITO vapor deposition glass substrate which is TCO, and the test pattern which is a solid coating of 25 mm x 25 mm was formed. It dried for 30 minutes at 200 degreeC in oven, and produced the electroconductive film.
About each produced conductive film, the volume resistivity immediately after production (initial stage) and after leaving it to stand at 85 ° C. and 85% humidity for 500 hours (after the moist heat resistance test) was measured with a resistivity meter (Lorestar GP, Mitsubishi Chemical Corporation). Measured by a 4-terminal 4-probe method using The results are shown in Table 2 below.
　＜密着性＞
　形成した各導電性被膜の基板に対する密着性の評価は、碁盤目はく離試験により行った。その結果を下記第２表に示す。
　具体的には、得られた各導電性被膜付き基板に、１ｍｍの基盤目を１００個（１０×１０）作り、基盤目上にセロハン粘着テープを完全に付着させ、指の腹で１０回こすった後、テープの一端を導電性膜に直角に保った状態で瞬間的に引き離し、完全に剥がれないで残った基盤目の数を調べた。完全に剥がれないで残った基盤目数が１００、即ち、全く剥がれなかったものが最も好ましい。 <Adhesion>
The evaluation of the adhesion of each formed conductive film to the substrate was performed by a grid peel test. The results are shown in Table 2 below.
Specifically, on each of the obtained substrates with conductive coating, 100 1 mm bases (10 × 10) were made, and cellophane adhesive tape was completely attached on the bases and rubbed 10 times with the belly of the finger. After that, one end of the tape was momentarily pulled apart while keeping one end of the tape at right angles to the conductive film, and the number of base meshes remaining without being completely peeled was examined. It is most preferable that the number of base meshes remaining without being completely peeled is 100, that is, those having not peeled off at all.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　第２表中の各成分は、以下のものを使用した。
　・銅粉：Ｃｕ－ＨＷＱ（形状：球状、平均粒子径：３．０μｍ、福田金属箔粉工業社製） The following were used for each component in Table 2.
Copper powder: Cu-HWQ (shape: spherical, average particle size: 3.0 μm, manufactured by Fukuda Metal Foil Powder Industry)
　・２－メチルプロパン酸銀塩：
　酸化銀（東洋化学工業社製）５０ｇ、２－メチルプロパン酸（関東化学社製）３８ｇおよびメチルエチルケトン（ＭＥＫ）３００ｇをボールミルに投入し、室温で２４時間撹拌させることにより反応させた。
　次いで、吸引ろ過によりＭＥＫを取り除き、得られた粉末を乾燥させることにより、２－メチルプロパン酸銀塩を調製した。 ・ Silver salt of 2-methylpropanoate:
50 g of silver oxide (manufactured by Toyo Kagaku Kogyo Co., Ltd.), 38 g of 2-methylpropanoic acid (manufactured by Kanto Chemical Co., Ltd.) and 300 g of methyl ethyl ketone (MEK) were placed in a ball mill and reacted by stirring at room temperature for 24 hours.
Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare silver 2-methylpropanoate.
　・２－エチル酪酸銀塩：
　酸化銀（東洋化学工業社製）５０ｇ、２－エチル酪酸（関東化学社製）５０．１３ｇおよびＭＥＫ３００ｇをボールミルに投入し、室温で２４時間撹拌させることにより反応させた。
　次いで、吸引ろ過によりＭＥＫを取り除き、得られた粉末を乾燥させることにより、２－エチル酪酸銀塩を調製した。 ・ 2-ethylbutyric acid silver salt:
50 g of silver oxide (manufactured by Toyo Chemical Co., Ltd.), 50.13 g of 2-ethylbutyric acid (manufactured by Kanto Chemical Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours.
Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare silver 2-ethylbutyrate.
　・ネオデカン酸銀塩：
　酸化銀（東洋化学工業社製）５０ｇ、ネオデカン酸（東洋合成社製）７４．３ｇおよびＭＥＫ３００ｇをボールミルに投入し、室温で２４時間撹拌させることにより反応させた。
　次いで、吸引ろ過によりＭＥＫを取り除き、得られた粉末を乾燥させることにより、ネオデカン酸銀塩を調製した。 ・ Neodecanoic acid silver salt:
50 g of silver oxide (manufactured by Toyo Kagaku Kogyo Co., Ltd.), 74.3 g of neodecanoic acid (manufactured by Toyo Gosei Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours.
Next, MEK was removed by suction filtration, and the obtained powder was dried to prepare a silver neodecanoate.
　・２－エチルヘキサン酸銀塩：
　酸化銀（東洋化学工業社製）５０ｇ、２－エチルヘキサン酸（関東化学社製）４９．２７ｇおよびＭＥＫ３００ｇをボールミルに投入し、室温で２４時間撹拌させることにより反応させた。
　次いで、吸引ろ過によりＭＥＫを取り除き、得られた粉末を乾燥させることにより、２－エチルヘキサン酸銀塩を調製した。 ・ 2-ethylhexanoic acid silver salt:
50 g of silver oxide (manufactured by Toyo Chemical Co., Ltd.), 49.27 g of 2-ethylhexanoic acid (manufactured by Kanto Chemical Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours.
Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare silver 2-ethylhexanoate.
　・ステアリン酸銀塩：
　酸化銀（東洋化学工業社製）５０ｇ、ステアリン酸（関東化学社製）１２３ｇおよびＭＥＫ３００ｇをボールミルに投入し、室温で２４時間撹拌させることにより反応させた。
　次いで、吸引ろ過によりＭＥＫを取り除き、得られた粉末を乾燥させることにより、ステアリン酸銀塩を調製した。 -Silver stearate:
50 g of silver oxide (manufactured by Toyo Chemical Co., Ltd.), 123 g of stearic acid (manufactured by Kanto Chemical Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours.
Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare a silver stearate salt.
　・１，２，３，４－ブタンテトラカルボン酸銀塩：
　まず、酸化銀（東洋化学工業社製）５０ｇ、１，２，３，４－ブタンテトラカルボン酸（新日本理化社製）２５．２９ｇおよびＭＥＫ３００ｇをボールミルに投入し、室温で２４時間撹拌させることにより反応させた。
　次いで、吸引ろ過によりＭＥＫを取り除き、得られた粉末を乾燥させることによって、１，２，３，４－ブタンテトラカルボン酸銀塩を調製した。 ・ 1,2,3,4-Butanetetracarboxylic acid silver salt:
First, 50 g of silver oxide (manufactured by Toyo Kagaku Kogyo Co., Ltd.), 25.29 g of 1,2,3,4-butanetetracarboxylic acid (manufactured by Shin Nippon Chemical Co., Ltd.) and 300 g of MEK are put into a ball mill and stirred at room temperature for 24 hours. Was reacted.
Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare 1,2,3,4-butanetetracarboxylic acid silver salt.
　・グルタル酸銀塩：
　酸化銀（東洋化学工業社製）５０ｇ、グルタル酸（関東化学社製）２８．５ｇおよびＭＥＫ３００ｇをボールミルに投入し、室温で２４時間撹拌させることにより反応させた。
　次いで、吸引ろ過によりＭＥＫを取り除き、得られた粉末を乾燥させることにより、グルタル酸銀塩を調製した。 ・ Glutaric acid silver salt:
50 g of silver oxide (manufactured by Toyo Chemical Co., Ltd.), 28.5 g of glutaric acid (manufactured by Kanto Chemical Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours.
Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare silver glutarate.
　・ｎ－酪酸銀塩：
　酸化銀（東洋化学工業社製）５０ｇ、ｎ－酪酸（関東化学社製）３８．０１ｇおよびＭＥＫ３００ｇをボールミルに投入し、室温で２４時間撹拌させることにより反応させた。
　次いで、吸引ろ過によりＭＥＫを取り除き、得られた粉末を乾燥させることにより、ｎ－酪酸銀塩を調製した。 N-butyric acid silver salt:
50 g of silver oxide (manufactured by Toyo Chemical Co., Ltd.), 38.01 g of n-butyric acid (manufactured by Kanto Chemical Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours.
Next, MEK was removed by suction filtration, and the obtained powder was dried to prepare silver n-butyrate.
　・ラウリン酸銀塩
　酸化銀（東洋化学工業社製）４０ｇ、ラウリン酸（関東化学社製）６８ｇおよびＭＥＫ３００ｇをボールミルに投入し、室温で２４時間撹拌させることにより反応させた。
　次いで、吸引ろ過によりＭＥＫを取り除き、得られた粉末を乾燥させることにより、ラウリン酸銀塩を調製した。 Silver laurate salt 40 g of silver oxide (manufactured by Toyo Chemical Co., Ltd.), 68 g of lauric acid (manufactured by Kanto Chemical Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours.
Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare silver laurate.
　・４－シクロヘキセン－１，２－ジカルボン酸銀塩：
　酸化銀（東洋化学工業社製）５０ｇ、４－シクロヘキセン－１，２－ジカルボン酸（新日本理化社製）３６．６７ｇおよびＭＥＫ３００ｇをボールミルに投入し、室温で２４時間撹拌させることにより反応させた。
　次いで、吸引ろ過によりＭＥＫを取り除き、得られた粉末を乾燥させることにより、４－シクロヘキセン－１，２－ジカルボン酸銀塩を調製した。 ・ 4-cyclohexene-1,2-dicarboxylic acid silver salt:
50 g of silver oxide (manufactured by Toyo Kagaku Kogyo Co., Ltd.), 36.67 g of 4-cyclohexene-1,2-dicarboxylic acid (manufactured by Shin Nippon Chemical Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours. .
Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare silver 4-cyclohexene-1,2-dicarboxylate.
　・アゼライン酸銀塩：
　酸化銀（東洋化学工業社製）５０ｇ、アゼライン酸（関東化学社製）４０．６０ｇおよびＭＥＫ３００ｇをボールミルに投入し、室温で２４時間撹拌させることにより反応させた。
　次いで、吸引ろ過によりＭＥＫを取り除き、得られた粉末を乾燥させることにより、アゼライン酸銀塩を調製した。 ・ Azelaic acid silver salt:
50 g of silver oxide (manufactured by Toyo Chemical Co., Ltd.), 40.60 g of azelaic acid (manufactured by Kanto Chemical Co., Ltd.) and 300 g of MEK were put into a ball mill and reacted by stirring at room temperature for 24 hours.
Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare azelaic acid silver salt.
　・２，２－ビス（ヒドロキシメチル）－ｎ－酪酸銀塩：
　酸化銀（東洋化学工業社製）５０ｇ、２，２－ビス（ヒドロキシメチル）－ｎ－酪酸（東京化成社製）６４ｇおよびＭＥＫ３００ｇをボールミルに投入し、室温で２４時間撹拌させることにより反応させた。
　次いで、吸引ろ過によりＭＥＫを取り除き、得られた粉末を乾燥させることにより、２，２－ビス（ヒドロキシメチル）－ｎ－酪酸銀塩を調製した。 2,2-bis (hydroxymethyl) -n-butyric acid silver salt:
50 g of silver oxide (manufactured by Toyo Kagaku Kogyo Co., Ltd.), 64 g of 2,2-bis (hydroxymethyl) -n-butyric acid (manufactured by Tokyo Chemical Industry Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours. .
Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare 2,2-bis (hydroxymethyl) -n-butyric acid silver salt.
　・２－ヒドロキシイソ酪酸銀塩：
　酸化銀（東洋化学工業社製）５０ｇ、２－ヒドロキシイソ酪酸（東京化成社製）４５ｇおよびＭＥＫ３００ｇをボールミルに投入し、室温で２４時間撹拌させることにより反応させた。
　次いで、吸引ろ過によりＭＥＫを取り除き、得られた粉末を乾燥させることにより、２－ヒドロキシイソ酪酸銀塩を調製した。 ・ 2-hydroxyisobutyric acid silver salt:
50 g of silver oxide (manufactured by Toyo Kagaku Kogyo Co., Ltd.), 45 g of 2-hydroxyisobutyric acid (manufactured by Tokyo Chemical Industry Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours.
Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare silver 2-hydroxyisobutyrate.
　・グリコール酸銀塩：
　酸化銀（東洋化学工業社製）５０ｇ、グリコール酸（関東化学社製）１６．４０ｇおよびＭＥＫ３００ｇをボールミルに投入し、室温で２４時間撹拌させることにより反応させた。
　次いで、吸引ろ過によりＭＥＫを取り除き、得られた粉末を乾燥させることにより、グリコール酸銀塩を調製した。 ・ Silver glycolate:
50 g of silver oxide (manufactured by Toyo Chemical Co., Ltd.), 16.40 g of glycolic acid (manufactured by Kanto Chemical Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours.
Next, MEK was removed by suction filtration, and the resulting powder was dried to prepare silver glycolate.
　・ヒドロキシピバル酸銀塩：
　酸化銀（東洋化学工業社製）５０ｇ、ヒドロキシピバル酸（関東化学社製）２５．４８ｇおよびＭＥＫ３００ｇをボールミルに投入し、室温で２４時間撹拌させることにより反応させた。
　次いで、吸引ろ過によりＭＥＫを取り除き、得られた粉末を乾燥させることにより、ヒドロキシピバル酸銀塩を調製した。 ・ Hydroxypivalic acid silver salt:
50 g of silver oxide (manufactured by Toyo Chemical Co., Ltd.), 25.48 g of hydroxypivalic acid (manufactured by Kanto Chemical Co., Ltd.) and 300 g of MEK were placed in a ball mill and reacted by stirring at room temperature for 24 hours.
Subsequently, MEK was removed by suction filtration, and the resulting powder was dried to prepare a hydroxypivalic acid silver salt.
　マロン酸銀塩：
　酸化銀（東洋化学工業社製）５０ｇ、マロン酸１１ｇおよびＭＥＫ３００ｇをボールミルに投入し、室温で２４時間撹拌させることにより反応させた。
　次いで、吸引ろ過によりＭＥＫを取り除き、得られた粉末を乾燥させることによって、マロン酸銀塩を調製した。 Malonic acid silver salt:
50 g of silver oxide (manufactured by Toyo Kagaku Kogyo Co., Ltd.), 11 g of malonic acid and 300 g of MEK were put into a ball mill and reacted by stirring at room temperature for 24 hours.
Subsequently, MEK was removed by suction filtration, and the obtained powder was dried to prepare silver malonate.
　・熱硬化性樹脂：ビスフェノールＡ型エポキシ樹脂（ＥＰ－４１００Ｅ、ＡＤＥＫＡ社製）
　・熱硬化性樹脂：ビスフェノールＦ型エポキシ樹脂（ＥＰ－４９０１Ｅ、ＡＤＥＫＡ社製）
　・熱硬化性樹脂：ウレタン変性エポキシ樹脂（ＥＰＵ－１３９５、ＡＤＥＫＡ社製）
　・硬化剤：三フッ化ホウ素エチルアミン（ステラケミファ社製）
　・溶媒：テルピネール Thermosetting resin: bisphenol A type epoxy resin (EP-4100E, manufactured by ADEKA)
Thermosetting resin: bisphenol F type epoxy resin (EP-4901E, manufactured by ADEKA)
-Thermosetting resin: Urethane-modified epoxy resin (EPU-1395, manufactured by ADEKA)
・ Curing agent: Boron trifluoride ethylamine (manufactured by Stella Chemifa)
・ Solvent: Terpinel
　第２表に示す結果から、熱分解ピーク温度と熱分解開始温度との差が４０℃未満の脂肪酸銀塩を用いて調製した比較例１～６の導電性組成物は、耐湿熱試験後の体積抵抗率が２桁も高くなることが分かった。
　また、脂肪酸銀塩の含有量が多い比較例２の導電性組成物は、密着性も劣ることが分かった。
　これに対し、熱分解ピーク温度と熱分解開始温度との差が４０℃以上の脂肪酸銀塩を用いて調製した導電性組成物は、耐湿熱試験後の体積抵抗率も低く、また、基板との密着性も優れることが分かった（実施例１～１７）。
　特に、実施例１～１３の対比から、熱分解ピーク温度と熱分解開始温度との差が１００℃以上であると、耐湿熱試験後の体積抵抗率をより低くできることが分かった。
　また、実施例８、１４および１５の対比から、熱硬化性樹脂（Ｃ）の含有量が銅粉（Ａ）１００質量部に対して１．０～５０質量部であると、形成される電極等の体積抵抗率がより低くなることが分かった。 From the results shown in Table 2, the conductive compositions of Comparative Examples 1 to 6 prepared using a fatty acid silver salt having a difference between the thermal decomposition peak temperature and the thermal decomposition starting temperature of less than 40 ° C. It was found that the volume resistivity was increased by two orders of magnitude.
Moreover, it turned out that the electroconductive composition of the comparative example 2 with much content of fatty acid silver salt is also inferior in adhesiveness.
On the other hand, the conductive composition prepared using a fatty acid silver salt having a difference between the thermal decomposition peak temperature and the thermal decomposition starting temperature of 40 ° C. or higher has a low volume resistivity after the wet heat resistance test, It was also found that the adhesiveness was excellent (Examples 1 to 17).
In particular, the comparison between Examples 1 to 13 reveals that the volume resistivity after the wet heat resistance test can be further reduced when the difference between the thermal decomposition peak temperature and the thermal decomposition start temperature is 100 ° C. or more.
Further, from the comparison with Examples 8, 14 and 15, when the content of the thermosetting resin (C) is 1.0 to 50 parts by mass with respect to 100 parts by mass of the copper powder (A), the formed electrode It has been found that the volume resistivity of etc. becomes lower.
　１、１００　太陽電池セル
　２　ｎ層
　３　反射防止膜
　４　表面電極
　５　ｐ層
　６　裏面電極
　７　シリコン基板
　１１　ｎ型単結晶シリコン基板
　１２ａ、１２ｂ　ｉ型アモルファスシリコン層
　１３ａ　ｐ型アモルファスシリコン層
　１３ｂ　ｎ型アモルファスシリコン層
　１４ａ、１４ｂ　透明導電層
　１５ａ、１５ｂ　集電電極 DESCRIPTION OF SYMBOLS 1,100 Solar cell 2 N layer 3 Anti-reflective film 4 Front surface electrode 5 P layer 6 Back surface electrode 7 Silicon substrate 11 N-type single crystal silicon substrate 12a, 12b i-type amorphous silicon layer 13a p-type amorphous silicon layer 13b n-type amorphous Silicon layer 14a, 14b Transparent conductive layer 15a, 15b Current collecting electrode

Claims (5)

  1. 　銅粉（Ａ）と、脂肪酸銀塩（Ｂ）と、熱硬化性樹脂（Ｃ）とを有する導電性組成物であって、
    　前記脂肪酸銀塩（Ｂ）の熱分解ピーク温度と熱分解開始温度との差が４０℃以上であり、
    　前記脂肪酸銀塩（Ｂ）の含有量が、前記脂肪酸銀塩（Ｂ）から生成する銀の量に換算して、前記銅粉（Ａ）１００質量部に対して２０～１００質量部である、導電性組成物。     A conductive composition comprising copper powder (A), a fatty acid silver salt (B), and a thermosetting resin (C),
    The difference between the thermal decomposition peak temperature of the fatty acid silver salt (B) and the thermal decomposition start temperature is 40 ° C. or higher,
    The content of the fatty acid silver salt (B) is 20 to 100 parts by mass with respect to 100 parts by mass of the copper powder (A) in terms of the amount of silver produced from the fatty acid silver salt (B). Conductive composition.
  2. 　前記熱硬化性樹脂（Ｃ）の含有量が、前記銅粉（Ａ）１００質量部に対して１～５０質量部である、請求項１に記載の導電性組成物。 The conductive composition according to claim 1, wherein the content of the thermosetting resin (C) is 1 to 50 parts by mass with respect to 100 parts by mass of the copper powder (A).
  3. 　請求項１または２に記載の導電性組成物を集電電極に用いた太陽電池セル。 A solar cell using the conductive composition according to claim 1 or 2 as a collecting electrode.
  4. 　前記集電電極の下地層として透明導電層を具備する請求項３に記載の太陽電池セル。 The solar cell according to claim 3, further comprising a transparent conductive layer as a base layer of the current collecting electrode.
  5. 　請求項３または４に記載の太陽電池セルを用いた太陽電池モジュール。 A solar battery module using the solar battery cell according to claim 3 or 4.
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WO2018155393A1 (en) * 2017-02-24 2018-08-30 Ｄｏｗａエレクトロニクス株式会社 Electroconductive paste

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