WO2012105581A1 - Method for producing oxide semiconductor layer - Google Patents

Method for producing oxide semiconductor layer Download PDF

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Publication number
WO2012105581A1
WO2012105581A1 PCT/JP2012/052196 JP2012052196W WO2012105581A1 WO 2012105581 A1 WO2012105581 A1 WO 2012105581A1 JP 2012052196 W JP2012052196 W JP 2012052196W WO 2012105581 A1 WO2012105581 A1 WO 2012105581A1
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WIPO (PCT)
Prior art keywords
oxide semiconductor
semiconductor layer
layer
fine particles
support
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PCT/JP2012/052196
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French (fr)
Japanese (ja)
Inventor
金子　直人
水野　幹久
亮介 岩田
武 両角
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ソニー株式会社
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Publication of WO2012105581A1 publication Critical patent/WO2012105581A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
    • H01G9/20—Light-sensitive devices
    • H01G9/2027—Light-sensitive devices comprising an oxide semiconductor electrode
    • H01G9/2031—Light-sensitive devices comprising an oxide semiconductor electrode comprising titanium oxide, e.g. TiO2
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02367—Substrates
    • H01L21/0237—Materials
    • H01L21/02422—Non-crystalline insulating materials, e.g. glass, polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02521—Materials
    • H01L21/02551—Group 12/16 materials
    • H01L21/02554—Oxides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02521—Materials
    • H01L21/02565—Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02518—Deposited layers
    • H01L21/02587—Structure
    • H01L21/0259—Microstructure
    • H01L21/02601—Nanoparticles
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02612—Formation types
    • H01L21/02617—Deposition types
    • H01L21/02623—Liquid deposition
    • H01L21/02628—Liquid deposition using solutions
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
    • H01G9/20—Light-sensitive devices
    • H01G9/2059—Light-sensitive devices comprising an organic dye as the active light absorbing material, e.g. adsorbed on an electrode or dissolved in solution
    • 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
    • Y02E10/542—Dye sensitized solar cells
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the primary particle average particle diameter of the second granular fine particles 2B is larger than 100 nm and not larger than 10,000 nm.
  • the larger the average particle diameter of the second granular fine particles 2B, the more the ratio of the blending mass of the second granular fine particles 2B to the blending mass of the first granular fine particles 2A ( (the blending mass of the second granular fine particles 2B). ) / (Mixed mass of the first particulate fine particles 2A)) is larger, the cracks generated in the semiconductor electrode layer (metal oxide semiconductor porous layer) 21 are reduced.
  • FIG. 2 shows an example including two types of granular fine particles having different average particle sizes of primary particles, but it is obvious that a configuration including three or more types of granular fine particles having different average particle sizes may be used. is there.
  • the average primary particle diameter of the second granular fine particles 2B is more preferably 200 nm or more and 5000 nm or less. When the average particle diameter of the primary particles is smaller than 200 nm, the effect of suppressing the occurrence of cracks in the semiconductor electrode layer 21 is insufficient, and the performance of scattering incident light tends to be insufficient.
  • the ratio of the blending mass of the second granular fine particles 2B to the blending mass of the first granular fine particles 2A is preferably 0.06 or more and 6 or less. When it is less than 0.06, the effect of suppressing the occurrence of cracks in the semiconductor electrode layer 21 becomes insufficient, and the performance of scattering incident light tends to be insufficient.
  • the effect of suppressing the occurrence of cracks in the semiconductor electrode layer 21 is sufficient and the performance of scattering incident light is sufficient, but the actual surface area of the metal oxide semiconductor particles in the semiconductor electrode layer 21 is sufficient.
  • This may decrease the performance of an electrochemical device using the semiconductor electrode layer 21, for example, a dye-sensitized solar cell.
  • the larger the ratio ( (the blending mass of the second particulate microparticles 2B) / (the blending mass of the first particulate microparticles 2A)) to the blending mass of the first particulate microparticles 2A is, the larger the semiconductor electrode layer 1 is.
  • a light scattering function is imparted to the semiconductor electrode layer 21 so that the internal HAZE of the semiconductor electrode layer 21 increases and the total light transmittance decreases. Further, by adsorbing the photosensitizing dye to the semiconductor electrode layer 21, the total light transmittance is further lowered.
  • the dispersion method known methods such as stirring treatment, ultrasonic dispersion treatment, bead dispersion treatment, kneading treatment, and homogenizer treatment can be preferably used.
  • the solvent a solvent that can disperse the metal oxide semiconductor fine particles 2 and 3 and can dissolve the first compound and the second compound is appropriately selected and used. Specifically, for example, it is selected from alcohols, ketones, hydrocarbons, amides, sulfides and the like.
  • the compounding quantity of the metal oxide semiconductor fine particles 2 and 3 is 1 mass% or more and 50 mass% or less of the mass of the coating liquid formed by adding the 1st compound and 2nd compound which are mentioned later, for example, 20 mass %.
  • a 1st compound is a compound which hydrolyzes and produces
  • the second compound is a compound that is harder to hydrolyze than the first compound and that produces a second oxide having a higher hardness than the first oxide when hydrolyzed.
  • a metal element salt or alkoxide may be used as the first compound.
  • the metal element may be at least one element selected from the group consisting of titanium Ti, aluminum Al, silicon Si, vanadium V, zirconium Zr, niobium Nb, and tantalum Ta.
  • the ratio of the second compound that is hydrolyzed until the firing step is small, and most of the second compound is preferably hydrolyzed by moisture supplied from the air in the firing step.
  • the second oxide generated by hydrolysis of the second compound is mainly bound on the first oxide layer 4 to form the second oxide layer 5, and the metal oxide
  • the first oxide layer 4 bonded between the semiconductor fine particles 2 and 3 and between the metal oxide semiconductor fine particles 2 and 3 and the support 6 is strongly reinforced.
  • a semiconductor electrode layer (metal oxide semiconductor porous layer) 1 or 23 having excellent mechanical strength and high adhesion to the support 6 is obtained.
  • the second compound may be used, but the second compound alone tends to cause surface layer peeling or damage. This is because the second compound is less reactive with the surface of the metal oxide semiconductor fine particles 2 and 3 than the first compound, so that the number of necking between the fine particles 2 and 3 is reduced only with the second compound. This is because the strength tends to be insufficient. That is, in order to achieve both the mechanical strength of the semiconductor electrode layer 1 or 23 and the adhesion to the support 6, it is preferable to use both the first compound and the second compound.
  • Electromagnetic wave treatment After the firing treatment, the metal oxide semiconductor porous layer is heated by electromagnetic wave irradiation in order to promote necking.
  • the method of manufacturing a semiconductor electrode layer according to the first embodiment of the present disclosure includes a process-saving process for manufacturing a film-type dye-sensitized solar cell, a reduction in the firing temperature of the metal oxide semiconductor porous layer on the glass substrate, Contributes to shortening process time and improving photoelectric conversion efficiency of film-type dye-sensitized solar cells.
  • the metal oxide semiconductor is heated to a temperature at which the resin film substrate is altered and deformed (for example, the heat resistance temperature of the resin film substrate or higher). This is because the resin film substrate tends to be deformed and deteriorated by heating because it is necessary to perform the treatment on the porous layer.
  • the specific heating temperature range is typically 40 ° C. or higher and 1000 ° C. or lower, and preferably 200 ° C. or higher and 550 ° C. or lower.
  • the treatment time is not particularly limited, but is usually 1 second or more and 10 hours or less.
  • the specific cooling temperature range is typically 150 ° C. or lower, preferably 0 ° C. or lower.
  • the gap between the cooling member and the support 6 is small. It is possible to prevent the resin film base material from being altered and deformed by bringing the cooling member and the support 6 into contact with each other without any gaps and sufficiently dissipating heat.
  • an antifreeze liquid such as a liquid having a low freezing point such as ethanol or methanol
  • a cooling medium layer such as a gel-like coolant or an antifreeze sheet is provided to cool the support 6 and the cooling member.
  • the support 6 may be cooled in a state where there is no gap between the members.
  • a cooling member is not limited to a cooling plate and a cooling roll, What is necessary is just to have a cooling function which cools the support body 6 to appropriate temperature.
  • the atmosphere in which electromagnetic waves are irradiated is oxygen It is preferable that the atmosphere does not contain. This is because when ITO is treated at a high temperature (for example, about 250 ° C. or higher) in an atmosphere containing oxygen such as the air, oxygen deficiency disappears and carriers are reduced by taking in oxygen, resulting in an increase in resistance. This is because there is a problem.
  • examples of the atmosphere not containing oxygen include, but are not limited to, an inert gas atmosphere such as nitrogen, argon, and helium, a vacuum, a hydrogen atmosphere, and the like.
  • an inert gas atmosphere such as nitrogen, argon, and helium
  • a vacuum such as a vacuum
  • a hydrogen atmosphere such as a vacuum
  • a hydrogen atmosphere such as a hydrogen
  • metal salts such as titanium tetrachloride and titanium alkoxide, and metal alkoxides Necking processing may be performed using.
  • ⁇ Pressure treatment of metal oxide semiconductor porous layer> In addition to the electromagnetic wave irradiation treatment, a treatment for enhancing the physical contact between the fillers of the semiconductor fine particle layer (metal oxide semiconductor porous layer) such as a calendar treatment and a press treatment may be performed. Thereby, for example, the energy conversion efficiency of the dye-sensitized solar cell can be improved.
  • the pressure treatment of the semiconductor fine particle layer may be performed before or after irradiation heating by electromagnetic wave irradiation treatment, or before and after.
  • ⁇ Calendar treatment or press treatment promotes contact between the semiconductor fine particles, increases the transparency of the semiconductor fine particle layer, and reduces the thickness of the semiconductor fine particle layer.
  • the conversion efficiency is improved.
  • the temperature of the press roll is less than 150 ° C.
  • the temperature of the back roll is less than 150 ° C.
  • the linear pressure is more than 0 ° C. and 500 kg / cm or less.
  • the load is 15 t / 25 mm within the range below the temperature that the glass can withstand. 2 The following is preferred.
  • the pressurizing process such as the calendar process or the press process may be performed twice or more.
  • the semiconductor electrode layer and the method for manufacturing the semiconductor electrode layer will be described in more detail.
  • the thickness of the semiconductor electrode layer 1 or 23 is preferably 1 ⁇ m or more and 30 ⁇ m or less. When the thickness is less than 1 ⁇ m, sufficient photoelectric conversion efficiency cannot be obtained. As the thickness is increased, the photoelectric conversion efficiency is improved.
  • the thickness is preferably 30 ⁇ m or less.
  • the material of the metal oxide semiconductor fine particles 2 and 3 various metal oxide semiconductors, compounds having a perovskite structure, and the like can be used.
  • the material of the metal oxide semiconductor fine particles 2 and 3 is preferably an n-type semiconductor material in which conduction band electrons become carriers under photoexcitation to generate an anode current.
  • Such a semiconductor material is specifically exemplified by TiO. 2 , ZnO, WO 3 , Nb 2 O 5 , SrTiO 3 , And SnO 2 Among these, TiO 2 Is particularly preferred.
  • the material of the metal oxide semiconductor fine particles 2 and 3 is not limited to these. Also, two or more of these materials can be mixed and used.
  • the average particle diameter of the primary particles is preferably 1 to 100 nm in the granular metal oxide semiconductor fine particles 2 (in this case, however, the metal Cracks occur in the oxide semiconductor porous layer, the conductivity between the metal oxide semiconductor fine particles decreases, and the photoelectric conversion performance of the dye-sensitized solar cell using the metal oxide semiconductor porous layer decreases.
  • the metal oxide semiconductor fine particles 2 and 3 commercially available products may be used, or a predetermined value may be obtained by subjecting chloride or alkoxide to hydrolysis treatment or hydrothermal treatment by a known method such as a sol-gel method. You may produce the thing of a particle size.
  • the crystal type thereof may be one type selected from a rutile type, anatase type, and brookite type, or a mixture of two or more types.
  • the granular metal oxide semiconductor fine particles 2 and 3 for example, MZ-300 and MZ-500 (manufactured by Teika Co., Ltd.) Product name), FZO-50 (product name) manufactured by Ishihara Sangyo Co., Ltd., NanoTek Powder series (product name) manufactured by CI Kasei Co., Ltd., FINEX series (product name) manufactured by Sakai Chemical Industry Co., Ltd. F-1, F-2, F-3, Pazet CK, Pazet GK-40 (above, trade name) manufactured by Co., Ltd. can be used.
  • MZ-300 and MZ-500 manufactured by Teika Co., Ltd.
  • FZO-50 product name
  • NanoTek Powder series product name
  • FINEX series product name manufactured by Sakai Chemical Industry Co., Ltd.
  • F-1, F-2, F-3, Pazet CK, Pazet GK-40 above, trade name
  • the first compound may be a compound of at least one element such as Ti, Al, Si, V, Zr, Nb, and Ta.
  • the element is the same element as the metal element constituting the metal oxide semiconductor fine particle 2, and the first oxide generated from the first compound and the metal oxide semiconductor fine particle 2 are formed.
  • the constituent metal oxide is preferably the same kind of oxide. It can be expected that the adhesion between the metal oxide semiconductor fine particles 2 and the first oxide layer 4 will be the best. Further, as the first compound, it is preferable to use the first compound hydrolyzed at room temperature by the water usually contained in the metal oxide semiconductor fine particles 2 and / or the organic solvent.
  • the hydrolysis of the first compound starts in the coating liquid, and the metal oxide semiconductor fine particles 2 are connected by the generated first oxide.
  • a network is easily formed.
  • the salt it is possible to use nitrates, sulfates, acetates, oxalates, halides, etc. that are soluble in a solvent.
  • TiOSO 4 , Zr (CH 3 COO) 2 O, Zr (CH 3 COO) 4 , Al (NO 3 ) 3 , Al (CH 3 COO) 3 , Al 2 (SO 4 ) 3 TiCl 4 AlCl 3 , Ti (C 2 O 4 ) 2 , Zr (C 2 O 4 ) 2 And Al 2 (C 2 O 4 ) 3 Etc. can be used.
  • the alkoxide that can be used can be represented by the following general formula.
  • the alkoxide may be modified with ⁇ -diketones such as acetylacetone.
  • a part of the alkoxy group may be substituted with a hydroxy group.
  • the commercial product for example, the following can be used. That is, Nippon Soda Co., Ltd. A-1, B-1, TOT, TOG, T-50, T-60, A-10, B-2, B-4, B-7, B-10, TBSTA, DPSTA-25, S-151, S-152, S-181, TAT, and TLA-A-50 (above, trade names), TPT, TBT, DBT, TST, TEAT, TAA, manufactured by Mitsubishi Gas Chemical Co., Ltd.
  • the oxide forming the second oxide layer 5 is SiO. 2 , B 2 O 3 , Al 2 O 3 And ZrO 2 It is preferable that the oxide has high hardness.
  • titanium oxide is used as the material of the metal oxide semiconductor fine particles 2 and 3, as the second compound, for example, dimethyldimethoxysilane Si (CH 3 ) 2 (OCH 3 ) 2 , Dimethyldiethoxysilane Si (CH 3 ) 2 (OCH 2 CH 3 ) 2 , Methyltrimethoxysilane Si (CH 3 ) (OCH 3 ) 3 , Methyltriethoxysilane Si (CH 3 ) (OCH 2 CH 3 ) 3 , Tetramethoxysilane Si (OCH 3 ) 4 , Tetraethoxysilane Si (OCH 2 CH 3 ) 4 Tetrapropoxysilane Si (OCH 2 CH 2 CH 3 ) 4 Tetrabutoxysilane Si (OCH 2 CH 2 CH 2 CH 3 ) 4 , Ethoxysilane dimer, ethoxysilane oligomer, ethoxysilane polymer, trimethoxyborane B (OCH 3 ) 3
  • a solvent capable of dissolving the first compound and the second compound and dispersing the metal oxide semiconductor fine particles 2 and 3 is used.
  • a solvent capable of dissolving the first compound and the second compound and dispersing the metal oxide semiconductor fine particles 2 and 3 is used.
  • DMF dimethylformamide
  • DMSO dimethyl sulfoxide
  • a high boiling point solvent can be added to control the evaporation rate of the solvent.
  • high-boiling solvents include butyl cellosolve, diacetone alcohol, butyl triglycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, diethylene glycol Monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol isopropyl ether, dipropylene glycol isopropyl ether Tripropylene glycol isopropyl ether,
  • ⁇ Roll-to-roll process The semiconductor electrode layer manufacturing process described above may be performed in a roll-to-roll process.
  • a material having poor heat resistance such as a resin film substrate such as a lightweight, inexpensive and flexible plastic film can be used for the support 6.
  • a material having poor heat resistance such as a resin film substrate such as a lightweight, inexpensive and flexible plastic film can be used for the support 6.
  • the semiconductor fine particle layer applied on one main surface of the film substrate 16 is subjected to a baking process for drying and necking the coating liquid.
  • the firing temperature is preferably equal to or lower than the glass transition point of the material constituting the film substrate 16 and is typically 40 ° C. or higher and 200 ° C. or lower.
  • it is about 30 seconds or more and 10 hours or less.
  • necking is promoted, but is not sufficient because it is fired at a low temperature. Necking can be further promoted and characteristics can be improved by electromagnetic wave treatment described later.
  • the metal oxide semiconductor porous layer is calendered by the back roll 34 and the press roll 35, thereby promoting the contact between the semiconductor fine particles and increasing the transparency of the metal oxide semiconductor porous layer 33.
  • the thickness of 33 is reduced.
  • the photoelectric conversion efficiency of the dye-sensitized solar cell can be improved.
  • the temperature of the press roll 35 is, for example, less than 150 ° C.
  • the temperature of the back roll 34 is less than 150 ° C.
  • the linear pressure is more than 0 kg / cm and not more than 500 kg / cm.
  • an antifreeze liquid layer 47 such as ethanol is preferably provided on the surface of the cooling roll 36.
  • the atmosphere in which the electromagnetic wave treatment is performed is preferably an atmosphere containing no oxygen. Examples of the atmosphere not containing oxygen include an inert gas atmosphere, a vacuum, and a hydrogen atmosphere.
  • ITO tends to increase in resistance because electromagnetic wave treatment in an atmosphere containing oxygen such as in the air eliminates oxygen deficiency and reduces carriers by incorporating oxygen. Therefore, when processing a conductive layer that cannot be baked in an oxygen atmosphere such as ITO, it is necessary to create an atmosphere containing no oxygen.
  • the inert gas include nitrogen gas, argon gas, helium gas, and the like.
  • an inert gas may be filled in an atmosphere-controllable chamber 44 as shown in FIG. 4, and electromagnetic wave treatment may be performed in this chamber, and inert gas or the like is sprayed onto the film substrate 16. In this way, electromagnetic wave processing may be performed.
  • the dye-sensitized solar cell 60 mainly includes a transparent substrate 61, a transparent conductive layer (negative electrode current collector) 62, a semiconductor electrode layer (negative electrode) 63 holding a photosensitizing dye, an electrolyte layer 64, and a counter electrode (positive electrode). 65, a counter substrate 66, a sealing material 67, and the like.
  • the semiconductor electrode layer 63 is made of the above-described titanium oxide TiO. 2 Or the like, and a photosensitizing dye is held on the surfaces of the metal oxide semiconductor fine particles 2 and 3 and the like.
  • Excited electrons are taken out to the conduction band of the semiconductor electrode layer 63 through electrical coupling between the photosensitizing dye and the semiconductor electrode layer 63, and reach the transparent conductive layer 62 through the semiconductor electrode layer 63.
  • the photosensitizing dye that has lost the electrons is a reducing agent in the electrolyte layer 64, such as I. ⁇
  • the generated oxidant reaches the counter electrode 65 by diffusion, and the reverse reaction of the above reaction.
  • the semiconductor electrode layer 1 or 21 is formed on the transparent conductive layer 62 provided on the transparent substrate 61 by the method for manufacturing a semiconductor electrode layer described above.
  • the photosensitizing dye to be held in the semiconductor electrode layer 63 is not particularly limited as long as it exhibits a sensitizing action.
  • xanthene dyes such as rhodamine B, rose bengal, eosin, erythrosine, merocyanine, quinocyanine, Cyanine dyes such as cryptocyanine, basic dyes such as phenosafranine, cabry blue, thiocin and methylene blue, other azo dyes, porphyrin compounds such as chlorophyll, zinc porphyrin and magnesium porphyrin, phthalocyanine compounds, coumarin compounds, ruthenium Examples include Ru bipyridine complexes, terpyridine complexes, anthraquinone dyes, polycyclic quinone dyes, squarylium dyes, and the like.
  • iodine I 2 An electrolyte in which lithium iodide LiI, sodium iodide NaI, or quaternary ammonium compound such as imidazolium iodide is combined is preferable.
  • the concentration of the electrolyte salt in the electrolytic solution is preferably 0.05M or more and 5M or less, more preferably 0.1M or more and 3M or less.
  • Iodine I 2 Or bromine Br 2 The concentration of is preferably from 0.0005M to 1M, and more preferably from 0.005M to 0.5M.
  • additives such as 4-tert-butylpyridine and carboxylic acid can be added for the purpose of improving the open circuit voltage and the short circuit current.
  • the sealing method can also seal by sticking a glass plate or a plastic substrate with a sealing material.
  • the electrolyte is an electrolyte gelled using a polymer or the like, or an all-solid electrolyte
  • a polymer solution containing an electrolyte and a plasticizer is applied onto the semiconductor electrode layer 63 by a casting method or the like.
  • the plasticizer is volatilized and completely removed, and then sealed with a sealing material in the same manner as described above.
  • This sealing is preferably performed using a vacuum sealer or the like in an inert gas atmosphere or in a reduced pressure.
  • Second embodiment A method for manufacturing an oxide semiconductor layer according to the second embodiment of the present disclosure will be described.
  • the manufacturing method of the oxide semiconductor layer according to the second embodiment of the present disclosure is, for example, a manufacturing method of a transparent oxide semiconductor layer formed on a resin film substrate such as a plastic film.
  • a resin film substrate such as a plastic film.
  • Base film As the base film 86, triacetyl cellulose (TAC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyester (TPEE), polyimide (PI), polyamide (PA), aramid, polyethylene (PE), Polyacrylate, polyethersulfone, polysulfone, polypropylene (PP), diacetylcellulose, polyvinyl chloride, acrylic resin (PMMA), polycarbonate (PC), epoxy resin, urea resin, urethane resin, melamine resin, and cycloolefin polymer resin (A resin film substrate such as a transparent plastic film made of a polymer material such as (COP) can be used.
  • TAC triacetyl cellulose
  • PET polyethylene terephthalate
  • PEN polyethylene naphthalate
  • TPEE polyester
  • PA polyimide
  • PA polyamide
  • PE Polyacrylate
  • polyethersulfone polysulfone
  • PP polypropylene
  • PP
  • the transparent oxide semiconductor layer 81 is formed on one main surface of the base film 86 by, for example, a vapor phase such as a PVD (Physical Vapor Deposition) method or a CVD (Chemical Vapor Deposition) method. It can be formed by the method. Moreover, it can form by liquid phase methods, such as electroplating, electroless plating, the apply
  • a vapor phase such as a PVD (Physical Vapor Deposition) method or a CVD (Chemical Vapor Deposition) method. It can be formed by the method. Moreover, it can form by liquid phase methods, such as electroplating, electroless plating, the apply
  • Electromagnetic wave treatment After forming the transparent oxide semiconductor layer 81, electromagnetic wave treatment is performed to promote necking of the transparent oxide semiconductor particles, which are transparent conductive particles. Since a plastic material, which is a base material having a low softening point such as a film material, is used as the material of the base film 86, the base film 86 is damaged by being irradiated with electromagnetic waves while cooling the base film 86. It is possible to reduce resistance by promoting necking without giving. Electromagnetic waves include infrared rays, ultraviolet rays and visible rays. Other irradiation type treatments include microwave treatment, flame treatment, plasma treatment in air, plasma treatment in vacuum, corona treatment, induction heating treatment and the like, and these methods may be used.
  • the transparent oxide semiconductor layer 81 When heating the transparent oxide semiconductor layer 81 at a temperature higher than the temperature at which the film is altered or deformed, in order to suppress the temperature of the film from being higher than the temperature at which the film is altered or deformed by heating, support is provided. It is preferable to perform the treatment while cooling the body (film).
  • the cooling of the support may be performed by bringing a cooling plate such as a copper plate and a cooling member such as a cooling roll into close contact with the surface of the base film 86 where the transparent oxide semiconductor layer 81 is not formed.
  • a cooling plate it mounts on the cooling plate of the base film 86 in which the transparent oxide semiconductor layer 81 was formed.
  • the surface of the base film 86 where the transparent oxide semiconductor layer 81 is not formed is a surface that is in close contact with the cooling plate.
  • the base film 86 is cooled from the surface side of the side in which the semiconductor fine particle film of the base film 86 is not formed with a cooling plate.
  • the surface of the cooling roll 36 is brought into close contact with one main surface of the base film 86 where the transparent oxide semiconductor layer 81 is not formed. Cooling takes place.
  • a refrigerant composed of an antifreeze such as ethylene glycol is circulated in the cooling roll 36, and the temperature is, for example, 0 ° C. or less. It is preferable to provide an antifreeze layer 47 such as ethanol on the surface of the cooling roll 36.
  • an antifreeze layer 47 such as ethanol on the surface of the cooling roll 36.
  • Examples of the atmosphere not containing oxygen include an inert gas atmosphere, a vacuum, and a hydrogen atmosphere.
  • ITO that is used as the transparent oxide semiconductor layer 81 has an increased resistance because an oxygen deficiency disappears and carriers are reduced by incorporating oxygen in an electromagnetic wave treatment in an atmosphere containing oxygen such as in the air. There is a tendency. Therefore, when ITO is used as the transparent oxide semiconductor layer 81, it is necessary to create an atmosphere that does not contain oxygen when heating by electromagnetic wave treatment is performed.
  • Examples of the inert gas include nitrogen gas, argon gas, helium gas, and the like.
  • Example 1 With reference to non-patent literature (Adv. Mater. 2003, 15, 2101), a dye-sensitized solar cell (opposing cell) was produced as follows. ⁇ Preparation of coating liquid> As the granular metal oxide semiconductor fine particles 2, the first granular titanium oxide fine particles 2A were used. As the first granular titanium oxide fine particles 2A, P25 (trade name; manufactured by Degussa, a mixture of anatase type crystal (80%) and rutile type crystal (20%), average particle size of primary particles is about 21 nm) was used.
  • P25 trade name; manufactured by Degussa, a mixture of anatase type crystal (80%) and rutile type crystal (20%), average particle size of primary particles is about 21 nm
  • This fine particle powder is mixed with ethanol so that the titanium oxide content is 30% by mass, and is subjected to a bead dispersion treatment with an agitator for 24 hours using zirconia beads having a diameter of 0.65 mm to form a granular metal oxide.
  • a dispersion of semiconductor fine particles 2 was prepared.
  • a predetermined amount of the first compound is added to the dispersion, stirred and mixed uniformly, a solvent is added to adjust the concentration, and the first titanium oxide fine particles 2A and the first compound are contained.
  • a coating solution was prepared. At this time, it was observed that the viscosity of the dispersion increased by the addition of the first compound.
  • butoxy titanium dimer Mitsubishi Gas Chemical Co., Ltd.
  • the blending amount in the coating liquid was kept constant at 2.5% by mass.
  • ethanol was used in all examples.
  • a PET film with an ITO layer manufactured by Oike Industry Co., Ltd.
  • the coating solution was applied to the support by a bar coating method using a coil bar (# 44) and then dried at room temperature.
  • the semiconductor fine particles The layer was calendered. Specifically, both the back roll 34 and the press roll 35 nipped the ITO / PET film with a semiconductor fine particle layer at a linear pressure of 1000 N / 15 mm. Thus, the semiconductor fine particle layer was continuously calendered. The number of calendar processes was one. Thereby, the adhesiveness of a support body (ITO / PET film) and a semiconductor fine particle layer improves, The clearance gap between fine particles is filled, and the effect that contact resistance falls is acquired.
  • the semiconductor fine particle layer was cut at the edge of the glass plate to a size of 5 mm ⁇ 5 mm, and then fired at 150 ° C. for 30 minutes to obtain a metal oxide semiconductor porous layer.
  • IR treatment Infrared treatment
  • the metal oxide semiconductor porous layer formed on one main surface of the ITO / PET film is irradiated with infrared rays using an infrared radiation heater (product name IR298, manufactured by Thermo Riko Co., Ltd.). Current output value 20A, treatment time 1 second) was performed and heated, and the other main surface of the ITO / PET film was brought into close contact with the cooling copper plate to cool the ITO / PET film.
  • D358 dye solution is a solution prepared by dissolving D358 dye (trade name; manufactured by Mitsubishi Paper Industries Co., Ltd.) in a mixed solvent in which acetonitrile and tert-butyl alcohol are mixed at a volume ratio of 1: 1 at a concentration of 0.5 mM. It is.
  • this semiconductor electrode metal oxide semiconductor porous layer
  • the acetonitrile was naturally evaporated and the semiconductor electrode was dried.
  • the counter electrode used was a carbon counter electrode formed on a SUS316 substrate.
  • ⁇ Assembly> Next, the two substrates were placed so that the semiconductor electrode layer and the counter electrode face each other, and bonded together via a silicon rubber sheet having a thickness of 30 ⁇ m. Next, an electrolyte solution was introduced between the electrodes using a capillary phenomenon to produce a dye-sensitized solar cell.
  • an electrolytic solution a solution in which 0.6 M iodide (1-propyl-3-methylimidazolium) and 0.1 M iodine were dissolved in 3-methoxypropionitrile was used.
  • This fine particle powder is mixed with ethanol so that the titanium oxide content is 14% by mass, and is subjected to bead dispersion treatment with an agitator for 24 hours using zirconia beads having a diameter of 0.65 mm, and the first granular oxidation.
  • a dispersion of titanium fine particles 2A was prepared.
  • TA-300 (trade name: manufactured by Fuji Titanium Industry Co., Ltd., anatase type crystal, average particle size of primary particles of about 390 nm) was used as the second granular fine particles 2B.
  • This fine particle powder was mixed with ethanol so that the titanium oxide content was 3.5% by mass, and was subjected to bead dispersion treatment with an agitator for 24 hours using zirconia beads having a diameter of 0.65 mm.
  • a dispersion of granular titanium oxide fine particles 2B was prepared.
  • each fine particle dispersion was mixed in a predetermined ratio.
  • a predetermined amount of the first compound is added to the dispersion, stirred and mixed uniformly, a solvent is added to adjust the concentration, and the titanium oxide fine particles 2A and 2B and the first compound are contained.
  • a coating solution was prepared. At this time, it was observed that the viscosity of the dispersion increased by the addition of the first compound.
  • butoxy titanium dimer Mitsubishi Gas Chemical Co., Ltd.
  • the blending amount in the coating liquid was kept constant at 2.5% by mass.
  • ethanol was used in all examples.
  • the first granular fine particles 2A and the second granular fine particles 2B which are the granular metal oxide semiconductor fine particles 2, two types of titanium oxide TiO 2 fine particles having a spherical shape and different sizes were used.
  • P25 trade name; manufactured by Degussa, a mixture of anatase type crystal (80%) and rutile type crystal (20%), average particle size of primary particles is about 21 nm
  • P25 trade name; manufactured by Degussa, a mixture of anatase type crystal (80%) and rutile type crystal (20%), average particle size of primary particles is about 21 nm
  • This fine particle powder was mixed with ethanol so that the titanium oxide content was 10.5% by mass, and the beads were dispersed with an agitator for 24 hours using zirconia beads having a diameter of 0.65 mm.
  • a dispersion of granular titanium oxide fine particles 2A was prepared.
  • TA-300 (trade name: manufactured by Fuji Titanium Industry Co., Ltd., anatase type crystal, average particle size of primary particles of about 390 nm) was used as the second granular fine particles 2B.
  • This fine particle powder was mixed with ethanol so that the titanium oxide content was 5.25% by mass, and was subjected to bead dispersion treatment with an agitator for 24 hours using zirconia beads having a diameter of 0.65 mm.
  • a dispersion of granular titanium oxide fine particles 2B was prepared.
  • acicular titanium oxide TiO 2 fine particles were used as the acicular metal oxide semiconductor fine particles 3.
  • FTL-300 trade name; manufactured by Ishihara Sangyo Co., Ltd., rutile type crystal, average primary particle diameter of about 0.27 ⁇ m, average length of about 5.15 ⁇ m
  • This fine particle powder is mixed with ethanol so that the titanium oxide content is 1.75% by mass, and the beads are dispersed with a zirconia bead having a diameter of 0.65 mm for 24 hours using a paint shaker.
  • a dispersion of the metal oxide semiconductor fine particles 3 was prepared.
  • each fine particle dispersion was mixed in a predetermined ratio.
  • a predetermined amount of the first compound is added to the dispersion, stirred and mixed uniformly, a solvent is added to adjust the concentration, and the titanium oxide fine particles 2A, 2B and 3 and the first compound are added.
  • a coating liquid containing was prepared. At this time, it was observed that the viscosity of the dispersion increased by the addition of the first compound.
  • butoxy titanium dimer Mitsubishi Gas Chemical Co., Ltd.
  • the blending amount in the coating liquid was kept constant at 2.5% by mass.
  • ethanol was used in all examples.
  • a PET film with an ITO layer having a surface resistance of 12 to 15 ⁇ / ⁇ manufactured by Oike Industry Co., Ltd.
  • a first coating liquid was applied on the support 6 by a bar coating method using a coil bar (# 30), and then dried at room temperature, thereby forming a first semiconductor fine particle layer on the support.
  • a second coating liquid is applied by a bar coating method using a coil bar (# 14) on the first semiconductor fine particle layer formed on the support, and then dried at room temperature, whereby the second A semiconductor fine particle layer was formed.
  • Example 3 ⁇ Preparation of coating liquid>
  • the first granular fine particles 2A and the second granular fine particles 2B which are the granular metal oxide semiconductor fine particles 2
  • two types of titanium oxide TiO 2 fine particles having a spherical shape and different sizes were used.
  • the first granular fine particles 2A P25 (trade name; manufactured by Degussa, a mixture of anatase type crystal (80%) and rutile type crystal (20%), average particle size of primary particles is about 21 nm) was used.
  • This fine particle powder is mixed with ethanol so that the titanium oxide content is 14% by mass, and is subjected to bead dispersion treatment with an agitator for 24 hours using zirconia beads having a diameter of 0.65 mm, and the first granular oxidation.
  • a dispersion of titanium fine particles 2A was prepared.
  • TA-300 (trade name: manufactured by Fuji Titanium Industry Co., Ltd., anatase type crystal, average particle size of primary particles of about 390 nm) was used as the second granular fine particles 2B.
  • This fine particle powder was mixed with ethanol so that the titanium oxide content was 3.5% by mass, and was subjected to bead dispersion treatment with an agitator for 24 hours using zirconia beads having a diameter of 0.65 mm.
  • a dispersion of granular titanium oxide fine particles 2B was prepared.
  • each fine particle dispersion was mixed in a predetermined ratio.
  • a predetermined amount of the first compound is added to the dispersion, stirred and mixed uniformly, a solvent is added to adjust the concentration, and the titanium oxide fine particles 2A and 2B and the first compound are contained.
  • a coating solution was prepared. At this time, it was observed that the viscosity of the dispersion increased by the addition of the first compound.
  • butoxy titanium dimer Mitsubishi Gas Chemical Co., Ltd.
  • the blending amount in the coating liquid was kept constant at 2.5% by mass.
  • ethanol was used in all examples.
  • the adhesiveness of a base material and a semiconductor fine particle layer improves, The clearance gap between fine particles is filled, and the effect that contact resistance falls is acquired.
  • the semiconductor fine particle layer was shaved with an edge of a glass plate to a size of 5 mm ⁇ 5 mm, and then fired at 150 ° C. for 30 minutes to obtain a metal oxide semiconductor porous layer.
  • ⁇ Infrared treatment> the semiconductor fine particle layer formed on one main surface of the glass substrate with an FTO layer is irradiated with infrared rays in the atmosphere using an infrared radiation heater (product name IR298, manufactured by Thermo Riko Co., Ltd.).
  • FIG. 1 shows the open-circuit voltage (VOC), short-circuit current (JSC), fill factor (FF), photoelectric conversion efficiency ( ⁇ ), and series resistance value of Examples 1 to 3 and Comparative Examples 1 to 3 ( Rs).
  • FIG. 8 is an IV curve when measuring the light conversion efficiency.
  • ⁇ is the IV curve of the counter cell of Example 1 prepared by performing the electromagnetic wave irradiation treatment
  • ⁇ is the IV curve of the counter cell of Comparative Example 1 manufactured without performing the electromagnetic wave irradiation treatment.
  • the current density is shifted upward as compared with the result of not performing the electromagnetic wave irradiation process. That is, it is considered that the application of electromagnetic wave irradiation improves the bonding between the semiconductor fine particles and decreases the resistance, resulting in an increase in current density.
  • the performance of the counter cell subjected to the electromagnetic wave irradiation treatment is superior to the performance of the counter cell not subjected to the electromagnetic wave irradiation treatment (Comparative Examples 1 to 3). Can be confirmed. 3.
  • Other Embodiments The present disclosure is not limited to the above-described embodiments of the present disclosure, and various modifications and applications are possible without departing from the gist of the present disclosure.
  • the numerical values, structures, shapes, materials, raw materials, processes, and the like given in the above-described embodiments and examples are merely examples, and numerical values, structures, shapes, materials, raw materials, processes that are different from these as necessary. Etc. may be used.
  • Transparent substrate 62 Transparent conductive layer 63 .
  • Semiconductor electrode layer 64 Electrolyte layer 65 .
  • Opposite Electrode 66 Counter substrate 67 .
  • Sealing material 81 Transparent acid Things semiconductor layer 86 ... substrate film

Abstract

Provided is a method for producing an oxide semiconductor layer that is able to perform heating processing in a high temperature region, at which resin film substrates are altered and deform, with respect to an oxide semiconductor layer formed on a support body, even if a support body containing a resin film substrate is used. A traveling film substrate is sequentially subjected to coating by a coating film, drying/baking processing, calendering processing, and electromagnetic wave processing. In the electromagnetic wave processing in an electromagnetic wave irradiation unit, a metal oxide semiconductor porous layer formed on the film substrate is heated by means of electromagnetic wave irradiation, and the film substrate is cooled by a cooling roller.

Description

酸化物半導体層の製造方法Method for manufacturing oxide semiconductor layer
　本開示は、酸化物半導体層の製造方法に関する。さらに詳しくは、例えば、プラスチックフィルム基材等を含む支持体上に形成される酸化物半導体層の製造方法に関する。 The present disclosure relates to a method for manufacturing an oxide semiconductor layer. More specifically, for example, the present invention relates to a method for manufacturing an oxide semiconductor layer formed on a support including a plastic film substrate or the like.
　色素増感型太陽電池（ＤＳＳＣ）は、電解質を利用できること、原料および製造コストが安価であること、色素利用のため装飾性を有すること等の特徴があり、近年、活発な研究がなされている。一般的に、色素増感型太陽電池は、導電膜が形成された基板と、この基板上に形成された半導体微粒子膜（ＴｉＯ２膜等）と色素とを組み合わせた酸化物半導体電極と、ヨウ素等の電荷輸送剤と、対極とから構成されている。
　色素増感型太陽電池の半導体微粒子膜は、通常、ＦＴＯガラス上にスクリーン印刷法等で塗布形成した後、５００℃付近の温度で高温焼成する。高温焼成により、半導体微粒子間のネッキングが向上し、これを用いた色素増感型太陽電池において変換効率が向上する。一方、基材に、ＩＴＯ層付ＰＥＮフィルム等の透明導電層付きプラスチックフィルム基材を用いた場合、透明導電層付きプラスチックフィルム基材の耐熱温度の制限から焼成温度は１５０℃以下としなければならない。このため、半導体微粒子膜のネッキングは不十分となり、光電変換効率が低下してしまう。
　特許文献１には、基板に透明酸化物半導体微粒子を含有する塗布液を塗装することで形成された塗布膜に対して、電磁波を照射して焼結する技術が開示されている。この先行技術文献には、電磁波として紫外線、赤外線、可視光線等が記載されている。また、焼成雰囲気に対して空気を遮断する方法として、不活性ガス雰囲気中での焼成、ガラスや金属板等による覆いを利用しての焼結等が記載されている。
　特許文献２には、色素増感型太陽電池の半導体微粒子膜を、マイクロ波を照射して焼結する技術が開示されている。この先行技術では、２８ＧＨｚのマイクロ波で半導体微粒子膜を焼結することにより、誘電損失を利用して半導体微粒子に選択的にエネルギーを与えて焼結を可能とし、通常の電気炉、それ以外の電磁波による焼結に比較して基材からの伝熱ロスがなく短時間に焼結が行える。
　また、特許文献２には、高分子フィルム基材に塗装した半導体微粒子膜を焼結する場合に、高分子フィルム基材が変質、変形しない温度（例えば、２００℃）になるように焼結することが記載されている。また、マイクロ波を照射して焼結する際に、必要に応じて高分子フィルム基材の裏面に、金属板、ガラス等の無機板等の放熱板を設置して、高分子フィルム基材に加わる熱を放熱することが記載されている。 Dye-sensitized solar cells (DSSC) are characterized by the fact that electrolytes can be used, raw materials and production costs are inexpensive, and that they have decorative properties for the use of dyes. In recent years, active research has been conducted. . In general, a dye-sensitized solar cell includes a substrate on which a conductive film is formed, an oxide semiconductor electrode obtained by combining a semiconductor fine particle film (such as a TiO 2 film) formed on the substrate and a dye, iodine And the like, and a counter electrode.
The semiconductor fine particle film of the dye-sensitized solar cell is usually formed by coating on FTO glass by a screen printing method or the like and then baked at a high temperature around 500 ° C. By high-temperature firing, necking between semiconductor fine particles is improved, and conversion efficiency is improved in a dye-sensitized solar cell using the same. On the other hand, when a plastic film substrate with a transparent conductive layer such as a PEN film with an ITO layer is used as the substrate, the firing temperature must be 150 ° C. or less due to the limitation of the heat resistance temperature of the plastic film substrate with a transparent conductive layer. . For this reason, necking of the semiconductor fine particle film becomes insufficient and the photoelectric conversion efficiency is lowered.
Patent Document 1 discloses a technique in which a coating film formed by coating a substrate with a coating liquid containing transparent oxide semiconductor fine particles is irradiated with electromagnetic waves and sintered. This prior art document describes ultraviolet rays, infrared rays, visible rays and the like as electromagnetic waves. In addition, as a method for shutting off air from the firing atmosphere, firing in an inert gas atmosphere, sintering using a cover with glass or a metal plate, and the like are described.
Patent Document 2 discloses a technique for sintering a semiconductor fine particle film of a dye-sensitized solar cell by irradiation with microwaves. In this prior art, by sintering a semiconductor fine particle film with a microwave of 28 GHz, it is possible to selectively give energy to the semiconductor fine particles by using dielectric loss, and to sinter the ordinary fine electric furnace. Compared with electromagnetic wave sintering, there is no heat transfer loss from the base material, and sintering can be performed in a short time.
Further, in Patent Document 2, when a semiconductor fine particle film coated on a polymer film substrate is sintered, the polymer film substrate is sintered so as to have a temperature (eg, 200 ° C.) that does not change or deform. It is described. In addition, when sintering by irradiating microwaves, a heat sink such as a metal plate or an inorganic plate such as glass is installed on the back surface of the polymer film substrate as necessary. It describes that the applied heat is dissipated.
特開平１１−２４２９１６号公報JP-A-11-242916 特開２００４−３４２３１９号公報JP 2004-342319 A
　特許文献１に記載の電磁波照射による焼結方法では、樹脂フィルム基材を用いた場合、樹脂フィルム基材が変質、変形するため、樹脂フィルム基材が変質、変形する高い温度域での加熱を透明酸化物半導体微粒子膜に対して行うことができない。このため樹脂フィルム基材を用いた場合には、加熱しても透明酸化物半導体微粒子の焼結が十分でなく、性能が優れた透明酸化物半導体微粒子膜を形成できない。
　特許文献２では、単に、マイクロ波照射による加熱の際に、高分子フィルム基材の裏面に設置された放熱板に、高分子フィルム基材に加わる熱を放熱しているだけなので、高分子フィルム基材が変質、変形する高い温度域での加熱を行うことできない。
　したがって、本開示の目的は、樹脂フィルム基材を含む支持体を用いた場合でも、樹脂フィルム基材が変質、変形する高い温度域での加熱処理を、支持体上に形成された酸化物半導体層に対して行うことができる酸化物半導体層の製造方法を提供することにある。 In the sintering method by electromagnetic wave irradiation described in Patent Document 1, when a resin film substrate is used, the resin film substrate is altered and deformed, so that heating at a high temperature range in which the resin film substrate is altered and deformed is performed. It cannot be performed on the transparent oxide semiconductor fine particle film. For this reason, when the resin film substrate is used, even if heated, the transparent oxide semiconductor fine particles are not sufficiently sintered, and a transparent oxide semiconductor fine particle film having excellent performance cannot be formed.
In Patent Document 2, since the heat applied to the polymer film substrate is simply radiated to the heat radiating plate installed on the back surface of the polymer film substrate during heating by microwave irradiation, the polymer film Heating in a high temperature range where the substrate is altered or deformed cannot be performed.
Therefore, an object of the present disclosure is to provide a heat treatment in a high temperature range in which a resin film substrate is altered or deformed even when a support including a resin film substrate is used. An object of the present invention is to provide a method for manufacturing an oxide semiconductor layer that can be performed on a layer.
　上述した課題を解決するために、本開示は、支持体に形成された酸化物半導体層を電磁波照射により加熱すると共に、上記支持体を冷却する工程を含む酸化物半導体層の製造方法である。
　本開示では、支持体に形成された酸化物半導体層を、電磁波照射により加熱すると共に、支持体を冷却する。これにより、樹脂フィルム基材を含む支持体であっても、樹脂フィルム基材が変質、変形する高い温度域での加熱処理を、支持体上に形成された酸化物半導体層に対して行うことができる。 In order to solve the above-described problem, the present disclosure is a method for manufacturing an oxide semiconductor layer including a step of heating an oxide semiconductor layer formed on a support by electromagnetic wave irradiation and cooling the support.
In the present disclosure, the oxide semiconductor layer formed on the support is heated by electromagnetic wave irradiation, and the support is cooled. Thereby, even if it is a support body containing a resin film base material, the heat processing in the high temperature range which a resin film base material changes and deform | transforms is performed with respect to the oxide semiconductor layer formed on the support body Can do.
　本開示によれば、樹脂フィルム基材を含む支持体を用いた場合でも、樹脂フィルム基材が変質、変形する高い温度域での加熱処理を、支持体上に形成された酸化物半導体層に対して行うことができる。 According to the present disclosure, even when a support including a resin film substrate is used, heat treatment in a high temperature range in which the resin film substrate is denatured and deformed is applied to the oxide semiconductor layer formed on the support. Can be done against.
　図１（ａ）は、支持体の上に形成された半導体電極層の断面図である。図１（ｂ）は、支持体に密着補助層が設けられ、その上に半導体電極層が形成されている例を示す断面図である。
　図２は、半導体電極層の構成例を示す断面図である。
　図３は、ロールツーロールプロセスによる半導体電極層の製造工程を説明するための略線図である。
　図４は、電磁波処理部の構成例を示す略線図である。
　図５は、色素増感型太陽電池の構成例を示す断面図である。
　図６は、透明酸化物半導体層付フィルムの構成例を示す断面図である。
　図７は、実施例で行ったカレンダー処理を説明するための略線図である。
　図８は、実施例１および比較例１のＩ−Ｖ曲線を示すグラフである。 FIG. 1A is a cross-sectional view of a semiconductor electrode layer formed on a support. FIG. 1B is a cross-sectional view showing an example in which a support auxiliary layer is provided on a support and a semiconductor electrode layer is formed thereon.
FIG. 2 is a cross-sectional view illustrating a configuration example of the semiconductor electrode layer.
FIG. 3 is a schematic diagram for explaining a manufacturing process of a semiconductor electrode layer by a roll-to-roll process.
FIG. 4 is a schematic diagram illustrating a configuration example of the electromagnetic wave processing unit.
FIG. 5 is a cross-sectional view showing a configuration example of a dye-sensitized solar cell.
FIG. 6 is a cross-sectional view illustrating a configuration example of a film with a transparent oxide semiconductor layer.
FIG. 7 is a schematic diagram for explaining the calendar process performed in the embodiment.
FIG. 8 is a graph showing IV curves of Example 1 and Comparative Example 1.
　以下、本開示の実施の形態について図面を参照して説明する。なお、説明は、以下の順序で行う。
１．第１の実施の形態（酸化物半導体層の製造方法の第１の例）
２．第２の実施の形態（酸化物半導体層の製造方法の第２の例）
３．他の実施の形態（変形例）
１．第１の実施の形態
　本開示の第１の実施の形態による酸化物半導体層の製造方法について説明する。本開示の第１の実施の形態による酸化物半導体層の製造方法は、典型的には、例えば、色素増感型太陽電池等の電気化学装置に用いる半導体電極層の製造方法である。
　まず、本開示の理解を容易にするため、この半導体電極層の製造方法により得られる、半導体電極層の構成例について、説明する。
（半導体電極層の第１の構成例）
　図１（ａ）は、支持体６の上に形成された半導体電極層１の断面図および部分拡大図である。半導体電極層１は、支持体６の上に配置された金属酸化物半導体微粒子２および３間、並びに金属酸化物半導体微粒子２および３と支持体６との間が、第１酸化物層４と第２酸化物層５とによって結着された金属酸化物半導体多孔質層である。半導体電極層１は、粒状の金属酸化物半導体微粒子２と針状の金属酸化物半導体微粒子３との、少なくとも２種類の形状の金属酸化物半導体微粒子を含有する。
　金属酸化物半導体微粒子２および３は、半導体電極層１の特性に応じて、酸化チタンＴｉＯ２、酸化亜鉛ＺｎＯ、酸化タングステンＷＯ３、酸化ニオブＮｂ２Ｏ５、チタン酸ストロンチウムＳｒＴｉＯ３、及び酸化スズＳｎＯ２からなる群から選ばれた少なくとも１種の酸化物からなるのがよい。
　多くの場合、第１酸化物層４を構成する金属元素が、金属酸化物半導体微粒子２および３を構成している金属元素と同一の金属元素であるのがよい。このようであると金属酸化物半導体微粒子２および３と第１酸化物層４の密着性が最良になることが期待される。第１酸化物層４は、主として直接、金属酸化物半導体微粒子２および３、並びに支持体６に結着している。
　第２酸化物層５は、第１酸化物層４を形成している第１の酸化物よりも硬度の高い第２の酸化物を含有し、主として第１酸化物層４を介して金属酸化物半導体微粒子２および３、並びに支持体６に結着している。第２酸化物層５は、第１酸化物層４を補強して、金属酸化物半導体微粒子２および３間、並びに金属酸化物半導体微粒子２および３と支持体６との間の結着を強化する働きをする。第２酸化物層５を構成する高硬度酸化物は、酸化ケイ素ＳｉＯ２、酸化ホウ素Ｂ２Ｏ３、酸化アルミニウムＡｌ２Ｏ３、及び酸化ジルコニウムＺｒＯ２からなる群から選ばれた少なくとも１種の酸化物であるのがよい。
　半導体電極層１は、金属酸化物半導体微粒子として粒状の金属酸化物半導体微粒子２（以下、粒状微粒子２ともいう）ばかりでなく、針状の金属酸化物半導体微粒子３（以下、針状微粒子３ともいう）をも含有している。このような場合、針状微粒子３を含有していない半導体電極層１に比べて導電性が向上する。この理由として、針状微粒子３が含まれていると、電子が、針状微粒子３の長さ方向の長い微粒子内導電路を利用することによって、抵抗の大きい、微粒子間の接合部を通過すること少なく、半導体電極層１内を移動できるようになることが考えられる。
　粒状微粒子２の一次粒子の平均粒子径は特に限定されるものではないが、１ｎｍ以上１００ｎｍ以下であると、可視光の透過性を高め、比表面積を大きくすることができるので好ましい。
　一方、針状微粒子３の一次粒子の平均直径は、０．１μｍ以上１μｍ以下であることが好ましく、平均長さは、１μｍ以上１０μｍ以下であることが好ましい。平均長さが１μｍよりも短い場合、針状微粒子３が半導体電極層１において効果的な導電路を形成することができず、その結果、半導体電極層１を用いた電気化学装置の性能を向上させる効果が不十分になる傾向がある。例えば、色素増感型太陽電池を構成した場合、集電効率を高め、光電変換効率を向上させる効果が不十分になる傾向がある。また、平均長さが１０μｍよりも長い場合、塗料のポットライフが劣化する傾向にある。
　針状微粒子３の配合質量の、粒状微粒子２の配合質量に対する比（＝（針状微粒子３の配合質量）／（粒状微粒子２の配合質量））は、０．０５以上０．２５以下であることが望ましい。０．０５未満の場合、針状微粒子３が少な過ぎて、半導体電極層１の導電性を向上させる効果が不十分である。一方、０．２５を超える場合、半導体電極層１の導電性を向上させる効果は大きいが、金属酸化物半導体多孔質層の実表面積が減少し、電極としての性能が低下する。この結果、例えば、半導体電極層１を有する色素増感型太陽電池を構成した場合、高い光電変換効率を実現できない。
　針状微粒子３を含有する塗料を調製する場合、針状微粒子３の分散の度合いは、分散が進んでいるほど好ましい。具体的には、例えば、ビーズ分散等の分散処理時間を長くするとよい。分散が進んでいると、半導体電極層１内に針状微粒子３による多数の導電路が均一に形成され、かつ、針状微粒子３の実表面積が増大する。この結果、針状微粒子３を含有する半導体電極層１の導電性が向上し、かつ、それを用いた電気化学装置の性能が向上する。例えば、色素増感型太陽電池として構成された電気化学装置において、集電効率が向上し、光電変換効率が向上する。
　支持体６と、半導体電極層１との間に密着補助層７を設ける構成としてもよい。図１（ｂ）は、支持体６に密着補助層７が設けられ、その上に半導体電極層１が形成されている例を示す断面図である。密着補助層７は、半導体電極層１と支持体６との密着性が十分でない場合に、密着性を向上させるために設けられる層である。密着性が不十分になりやすい例としては、支持体６が、表面にＩＴＯ層が設けられている基材である例を挙げることができる。密着補助層７の材料としては、ポリアクリレート系樹脂、ポリアミド系樹脂、ポリアミドイミド系樹脂、ポリエステル系樹脂、および金属元素の塩化物（四塩化チタン等）や過酸化物（過酸化チタン等）やアルコキシド等の加水分解・脱水縮合生成物等を用いることができる。半導体電極層１を色素増感型太陽電池の半導体電極層として用いる場合には、密着補助層７の厚さは、色素増感型太陽電池の光電変換効率を著しく低下させない厚さとすることが望ましい
　支持体６は用いられる環境において安定であればよく、それ以外に特に制限されない。支持体６の材料は、無機材料であっても、有機材料であってもよい。また、支持体６の形状も特に制限されることはなく、例えば、フィルム状、シート状、および板状等である。また、支持体６の材料が、電気化学装置に外部から侵入しようとする水分やガスを阻止する遮断性能が高く、また、耐溶剤性や耐候性に優れている材料であるのが好ましい。支持体６の厚さは特に制限されず、光の透過率や、水蒸気の透過を遮断する遮断性能や、機械的強度等を勘案して、適宜選択することができる。
　半導体電極層１を色素増感型太陽電池の半導体電極層として用いる場合のように、支持体６が光透過性であることが求められる場合には、支持体６として、光が透過しやすい材質と形状のものを用いる。例えば、石英、サファイア、ガラス等の透明無機基板、および、トリアセチルセルロース（ＴＡＣ）、ポリエチレンテレフタラート（ＰＥＴ）、ポリエチレンナフタラート（ＰＥＮ）、ポリエステル（ＴＰＥＥ）、ポリイミド（ＰＩ）、ポリアミド（ＰＡ）、アラミド、ポリエチレン（ＰＥ）、ポリアクリレート、ポリエーテルスルホン、ポリスルホン、ポリプロピレン（ＰＰ）、ジアセチルセルロース、ポリ塩化ビニル、アクリル樹脂（ＰＭＭＡ）、ポリカーボネート（ＰＣ）、エポキシ樹脂、尿素樹脂、ウレタン樹脂、メラミン樹脂、およびシクロオレフィンポリマー樹脂（ＣＯＰ）等の高分子材料からなる透明プラスチック基板が挙げられる。これらの中でも、特に可視光の透過率が高い基板材料を用いるのが好ましい。プラスチック基板の厚さは、特に限定されるものではないが、生産性の観点から３８μｍ以上５００μｍ以下であることが好ましい。
　また、支持体６として、光透過性基材上に透明導電層が形成された透明導電層付き光透過性基材を用いてもよい。この透明導電層の材料としては公知のものが使用可能であり、具体的にはＩＴＯ（酸化インジウムスズ）、ＦＴＯ（フッ素ドープ酸化スズ）、アンチモンがドープされた酸化スズ（ＡＴＯ）、酸化スズ（ＳｎＯ２）、酸化亜鉛、インジウム・亜鉛複合酸化物（ＩＺＯ）等が挙げられるが、これらに限定されるものではない。透明導電層は、これらの材料の単層膜でも、積層膜でもよく、２種類以上の材料を組み合わせて用いることもできる。なお、ＩＴＯに関しては、大気中で約２５０℃以上の高温で処理をすると酸化による劣化が生じてしまう。酸化により酸素欠損が埋まり、これによりキャリアが減少してしまい、導電率が低下する傾向にある。従って、ＩＴＯを使用した場合、高温で熱処理する際には酸素含まない雰囲気中で熱処理を行うことが好ましい。
（半導体電極層の第２の構成例）
　半導体電極層の第２の構成例について説明する。図２は、支持体６の上に形成された半導体電極層２１の断面図および部分拡大図である。半導体電極層２１は、支持体６の上に配置された金属酸化物半導体微粒子２および３間、並びに金属酸化物半導体微粒子２および３と支持体６との間が、第１酸化物層４と第２酸化物層５とによって結着された金属酸化物半導体多孔質層である。半導体電極層の第２の構成例が、第１の構成例と異なるのは、半導体電極層２１を形成している粒状金属酸化物半導体微粒子２が、一次粒子の平均粒子径が１００ｎｍ以下の第１の粒状微粒子２Ａと、一次粒子の平均粒子径が１００ｎｍより大きく、１００００ｎｍ以下である第２の粒状微粒子２Ｂとの、大きさが異なる２種類の微粒子からなることである。これ以外は半導体電極層の第１の構成例と同様であるので、重複を避け、相違点に重点をおいて説明する。
　粒状の金属酸化物半導体微粒子２のうち、第１の粒状微粒子２Ａは、一次粒子の平均粒子径が１ｎｍ以上１００ｎｍ以下であるので、可視光の透過性を高め、比表面積を大きくすることができる。一方、第２の粒状微粒子２Ｂの一次粒子平均粒子径は、１００ｎｍよりも大きく、１００００ｎｍ以下である。第２の粒状微粒子２Ｂの平均粒子径が大きいほど、また、第２の粒状微粒子２Ｂの配合質量の、第１の粒状微粒子２Ａの配合質量に対する比（＝（第２の粒状微粒子２Ｂの配合質量）／（第１の粒状微粒子２Ａの配合質量））が大きいほど、半導体電極層（金属酸化物半導体多孔質層）２１に発生するクラックは減少する。
　この理由が完全に解明されたとは言えないが、比較的大きな第２の粒状微粒子２Ｂが共在する場合には、第２の粒状微粒子２Ｂとその周囲の第１の粒状微粒子２Ａとの連結は、粒状微粒子２Ｂの表面上で確実に十分な結着強度で形成されることや、同じ長さの導電路を形成するために連結する必要のある粒子数が比較的少数になるので、結着強度が不十分になりやすい第１の粒状微粒子２Ａ間の連結部が著しく少なくなることが考えられる。従って、図２では一次粒子の平均粒子径が異なる２種類の粒状微粒子を含む例を示したが、平均粒子径が異なる３種類以上の粒状微粒子を含む構成であってもよいのは、明らかである。
　また、第２の粒状微粒子２Ｂが共存すると、入射光が散乱されやすくなり、半導体電極層２１の内部ＨＡＺＥ（ヘイズ）が上昇し、全光線透過率が低下する。この半導体電極層２１を用いた色素増感型太陽電池では、入射光の散乱によって光利用率が高まり、光電変換性能が向上する。
　第２の粒状微粒子２Ｂの一次粒子平均粒子径は、２００ｎｍ以上５０００ｎｍ以下であるのがより好ましい。一次粒子の平均粒子径が２００ｎｍよりも小さい場合、半導体電極層２１におけるクラックの発生を抑える効果が不十分となり、また、入射光を散乱する性能も十分でない傾向がある。一方、一次粒子の平均粒子径が５０００ｎｍよりも大きい場合、第２の粒状微粒子２Ｂが塗液中で沈殿しやすくなり、塗液のポットライフが低下する傾向がある。
　また、第２の粒状微粒子２Ｂの配合質量の、第１の粒状微粒子２Ａの配合質量に対する比は、０．０６以上６以下であることが好ましい。０．０６未満である場合、半導体電極層２１におけるクラックの発生を抑える効果が不十分となり、また、入射光を散乱する性能も十分でない傾向がある。一方、６よりも大きい場合、半導体電極層２１におけるクラックの発生を抑える効果は十分であり、入射光を散乱する性能も十分であるが、半導体電極層２１における金属酸化物半導体微粒子の実表面積が減少し、この半導体電極層２１を用いた電気化学装置、例えば色素増感型太陽電池の性能の低下を招くことがある。
　針状微粒子３の配合質量の、粒状微粒子２の配合質量に対する比（＝（針状微粒子３の配合質量）／（粒状微粒子２の配合質量））が大きいほど、また、第２の粒状微粒子２Ｂの配合質量の、第１の粒状微粒子２Ａの配合質量に対する比（＝（第２の粒状微粒子２Ｂの配合質量）／（第１の粒状微粒子２Ａの配合質量））が大きいほど、半導体電極層１に光散乱機能が付与されて、半導体電極層２１の内部ＨＡＺＥが上昇し、全光線透過率は低下する。また、半導体電極層２１に光増感色素を吸着させることにより、全光線透過率はさらに低下する。粒状微粒子２Ａおよび２Ｂ、並びに針状微粒子３の配合質量を、内部ＨＡＺＥ値が８５％以上であり、全光線透過率が５０％以下となるように、既述した範囲内にて選択するのがよい。このようにすることにより、半導体電極層２１を用いた色素増感型太陽電池において、光利用率が向上し、光電変換性能が向上する。
　針状微粒子３が半導体電極層（金属酸化物半導体多孔質層）２１に含まれていると、半導体電極層２１の硬度と基材への密着性を維持しながら、光電変換効率を向上させることができる。しかも、針状微粒子３が含有されていることが原因で、塗液の塗布または印刷後の溶媒蒸発工程及び／又は焼成工程において、半導体電極層２１にクラックが発生することはない。ただし、針状微粒子３がクラックの発生を抑える作用はないか、又は十分ではない。従って、半導体電極層２１に針状微粒子３を含有させることで内部ＨＡＺＥおよび全光線透過率を上記の範囲内にすることはできるが、半導体電極層２１に粒状微粒子２Ｂを含有させないと、半導体電極層２１におけるクラックの発生を抑えることができない場合がある。
（半導体電極層の製造方法）
　本開示の第１の実施の形態による半導体電極層の製造方法について説明する。例えば、上述した半導体電極層１または２１の製造方法について説明する。本開示の第１の実施の形態による半導体電極層の製造方法を用いることによって、支持体６に対する、半導体電極層の付着性の性能が優れると共に、樹脂フィルム基材を含む支持体６であっても高温で半導体電極層の焼結処理を行うことが可能となる。そして、色素増感型太陽電池に用いた場合において、光電変換効率の優れた半導体電極層１または２１を形成できる。
＜塗液の調製＞
　例えば、図１に示す半導体電極層１を作製するには、まず、金属酸化物半導体微粒子２および３を、それぞれ、適当な有機溶媒に分散させ、ペースト状の分散液を２つ調製する。分散方法としては、公知の方法、例えば、攪拌処理、超音波分散処理、ビーズ分散処理、混錬処理、およびホモジナイザー処理等を好ましく用いることができる。
　溶媒としては、金属酸化物半導体微粒子２および３を分散させることができ、かつ、第１の化合物および第２の化合物を溶解させることができるものを適宜選択して用いる。具体的には、例えば、アルコール類、ケトン類、炭化水素類、アミド類、およびスルフィド類等から選択して用いる。
　金属酸化物半導体微粒子２および３の配合量は、後述する第１の化合物および第２の化合物を添加して形成される塗液の質量の１質量％以上５０質量％以下であり、例えば２０質量％程度とする。１質量％未満である場合には、塗布法によって、十分な厚さを有する金属酸化物半導体微粒子層を形成することができない不都合がある。一方、５０質量％よりも大きい場合には、塗液の粘度が高くなりすぎて、塗布法等によって金属酸化物半導体微粒子層を形成する際の、取り扱いが困難になる不都合がある。
　次に、上記２つの分散液を所定の比率で混合し、これに第１の化合物および第２の化合物を添加し、攪拌して溶解させ、均一な塗液とする。濃度調整のため、溶媒をさらに追加してもよい。第１の化合物と第２の化合物とを添加する順序はどちらが先でもよい。第１の化合物は、加水分解して第１の酸化物を生じる化合物である。第２の化合物は、第１の化合物より加水分解しにくく、かつ加水分解すると上記第１の酸化物より硬度の高い第２の酸化物を生じる化合物である。
　具体的には、第１の化合物として、金属元素の塩又はアルコキシドを用いるのがよい。この金属元素は、例えば、チタンＴｉ、アルミニウムＡｌ、ケイ素Ｓｉ、バナジウムＶ、ジルコニウムＺｒ、ニオブＮｂ、およびタンタルＴａからなる群から選ばれた少なくとも１種の元素であるのがよい。また、未精製の金属酸化物半導体微粒子や有機溶媒には、通常、多かれ少なかれ吸着または吸蔵された水分が含まれているが、第１の化合物として、これらの水分と室温において反応し、一部又は全部が塗液中で加水分解される化合物を用いるのが好ましい。この場合、塗液の調製中に粘度が増加するのが観察される。これは、第１の化合物と金属酸化物半導体微粒子および有機溶媒との混合が進むと、第１の化合物が水分と反応し、第１の化合物の加水分解によって生成した第１の酸化物が金属酸化物半導体微粒子２および３の表面に結合し、金属酸化物半導体微粒子２および３間を連結していくためであると考えられる。
　一方、第２の化合物としては、ケイ素Ｓｉ、ホウ素Ｂ、アルミニウムＡｌ、およびジルコニウムＺｒからなる群から選ばれた少なくとも１種の元素のアルコキシドを用いるのがよい。
　第１の化合物の配合量は、例えば、塗液の質量の０．０１質量％以上２０質量％以下とする。また、第２の化合物の配合量は、例えば、塗液の質量の０．０１質量％以上２０質量％以下とする。第１の化合物および第２の化合物の配合量は、半導体電極層１の、所望の硬度と支持体への密着性とを得るために、金属酸化物半導体微粒子２および３の材料や分散性、第１の化合物および第２の化合物の材料種に応じて、上記範囲内において適宜選択する。第１の化合物および第２の化合物の配合量が上記の範囲外である場合、半導体電極層１の硬度と支持体６への密着性とを両立させることが難しくなる傾向がある。また、半導体電極層１を色素増感型太陽電池の半導体電極層として用いる場合には、第１の化合物および第２の化合物の材料種によっては、光増感色素の吸着が阻害されて、光電変換効率が低下することもある。
　図２に示す半導体電極層２１を作製する場合には、まず、金属酸化物半導体微粒子２および３を構成する第１の粒状微粒子２Ａ、第２の粒状微粒子２Ｂ、および針状微粒子３を、それぞれ、適当な有機溶媒に分散させ、ペースト状の分散液を３つ調製する。次に、上記３つの分散液を所定の比率で混合し、これに第１の化合物および第２の化合物を添加し、攪拌して溶解させ、均一な塗液とする。
＜半導体電極層の形成＞
　次に、公知の方法、例えば、塗布法または印刷法等によって、支持体６の上に上記塗液の層を被着させる。塗布方法としては、例えば、マイクログラビアコート法、ワイヤーバーコート法、ダイレクトグラビアコート法、ダイコート法、ディップ法、スプレーコート法、リバースロールコート法、カーテンコート法、コンマコート法、ナイフコート法、スピンコート法等を用いることができる。また、印刷方法としては、例えば、凸版印刷法、オフセット印刷法、グラビア印刷法、凹版印刷法、ゴム版印刷法、およびスクリーン印刷法等を用いることができる。
　次に、塗液の層から溶媒を蒸発させて除去し、第１の化合物、第２の化合物、および第１の酸化物を含有する金属酸化物半導体微粒子層を形成する。溶媒を蒸発させる方法としては、室温で蒸発させてもよいし、加熱して蒸発させてもよい。ただし、蒸発むらを抑えるために、溶媒の蒸発速度を調整することが好ましい。具体的には、２０℃以上１００℃以下の温度範囲、３０秒間~２０分間の時間範囲で蒸発させるのが好ましい。溶媒が蒸発して除かれると、塗液に含まれていた第１の酸化物は、金属酸化物半導体微粒子２および３に結着する。第１の化合物は空気中の水分と反応して加水分解する。この結果、第１の化合物は、次の焼成工程に入る前に大部分が第１の酸化物に変化する。そして、金属酸化物半導体微粒子２および３間、並びに金属酸化物半導体微粒子２および３と支持体６との間が、第１酸化物層４によって結着された金属酸化物半導体多孔質層が形成される。この際、第１の化合物の加水分解を促進するために、蒸発工程中及び／又は蒸発工程後の温度を２５℃以上２００℃以下、例えば８０℃程度に保ってもよい。また、蒸発工程と下記焼成工程とを同時に行うことも可能である。
＜焼成処理＞
　次に、金属酸化物半導体多孔質層を焼成して、金属酸化物半導体微粒子２および３間の電子的な接続を向上させ、また、金属酸化物半導体多孔質層の機械的強度と、支持体６との密着性とを向上させる。焼成温度に特に制限はないが、温度が高すぎると支持体６が熱で劣化することもあるので、焼成温度は４０℃以上１０００℃以下であり、通常、３００℃以上６００℃以下程度であることが好ましい。支持体６の材料としてプラスチック材料を用いる場合には、その耐熱温度以下（例えばガラス転移点以下等）、通常、４０℃以上２００℃以下であることが好ましい。また、焼成時間に特に制限はないが、通常、３０秒間以上１０時間以下程度である。
　この焼成工程で、微粒子同士が接点近傍で融着し、微粒子間が細かい連結部を介してネットワーク状に連結され、微粒子間の空隙が空孔として残された金属酸化物半導体多孔質層が形成される。（以下、接点近傍での融着によって、微粒子間が細かい連結部を介して連結される現象をネッキングと言い、この様な連結を形成する処理をネッキング処理ということがある。）この金属酸化物半導体多孔質層は、光増感色素を吸着させると、色素増感型太陽電池の半導体電極層として用いることができる。
　この際、焼成工程までに加水分解される第２の化合物の割合は少なく、大部分の第２の化合物が、焼成工程において空気中から供給される水分によって加水分解されることが好ましい。このようであると、第２の化合物の加水分解によって生成する第２の酸化物は、主として第１酸化物層４の上に結着して第２酸化物層５を形成し、金属酸化物半導体微粒子２および３間、並びに金属酸化物半導体微粒子２および３と支持体６との間に結着している第１酸化物層４を強固に補強する。この結果、機械的強度に優れ、支持体６との密着性の高い半導体電極層（金属酸化物半導体多孔質層）１または２３が得られる。
　なお、第１の化合物のみでもよいが、第１の化合物のみでは、半導体電極層（金属酸化物半導体多孔質層）１または２３と支持体６との密着性が不十分になることがある。なぜなら、加水分解が起こりやすい第１の化合物は、塗液を支持体６に被着させる前にかなりの部分が加水分解する。この塗液を支持体６に被着させる以前に生成した第１の酸化物は、金属酸化物半導体微粒子２および３間を連結し、金属酸化物半導体多孔質層の機械的強度を高める上では寄与するが、支持体６との密着性を高める上では寄与しないからである。これに対し、第２の化合物の加水分解は大部分が塗液を支持体６に被着させた後に起こるので、第２の酸化物は、金属酸化物半導体多孔質層の機械的強度の向上にも、支持体６との密着性の向上にも、同様に寄与する。第２の化合物のみでもよいが、第２の化合物だけでは、表層剥がれや傷つきが生じやすい。これは、第２の化合物は金属酸化物半導体微粒子２および３の表面との反応性が第１の化合物に比べて低いので、第２の化合物のみでは微粒子２および３間のネッキング数が少なくなり、強度不足になりやすいからである。すなわち、半導体電極層１または２３の機械的強度と支持体６への密着性とを両立させるには、第１の化合物と第２の化合物との両方を用いることが好ましい。
＜電磁波処理＞
　焼成処理後、ネッキングを促進させるため、電磁波照射による金属酸化物半導体多孔質層の加熱を行う。支持体６の材料としてプラスチック材料等の軟化点の低い材料を用いる場合、金属酸化物半導体多孔質層に対して、電磁波照射することで加熱すると共に、支持体６を冷却する。なお、上述した焼成処理を省略し、焼成処理の代わりに電磁波処理により、ネッキング処理を行ってもよい。本開示の第１の実施の形態による半導体電極層の製造方法は、フィルム型色素増感型太陽電池の製造の省プロセス化、ガラス基材上の金属酸化物半導体多孔質層の焼成温度低下、プロセス時間短縮、フィルム型色素増感型太陽電池の光電変換効率向上に寄与する。なお、背景技術の欄で例示した特許文献２には、２８ＧＨｚのマイクロ波で半導体微粒子膜を焼結にすることにより、誘電損失を利用して半導体微粒子に選択的にエネルギーを与えて焼結を可能とし、通常の電気炉、それ以外の電磁波による焼結に比較して基材からの伝熱ロスがなく短時間に焼結が行えるが、フィルムが変質したり、変形したりしてしまう温度域での加熱ができるとの報告はなく、１５０℃での低温焼結と比較して色素増感光電変換素子にした際の変換効率が向上するという報告も入っていない。また、マイクロ波照射装置は大型のものであり、バッチ式向けであるため、ロールツーロールプロセス等には不向きである。
　電磁波としては、例えば、赤外線、紫外線、可視光線等が挙げられる。その他の照射タイプの処理として、マイクロ波処理、フレーム処理、大気中プラズマ処理、真空中プラズマ処理、コロナ処理、誘導加熱処理等が挙げられ、これらの方法を用いてもよい。
　支持体６が、樹脂フィルム基材、例えばプラスチックフィルム基材のように、プラスチック材料等の軟化点の低い材料を用いるものである場合、支持体６を冷却しながら電磁波照射を行うことが好ましい。電磁波照射によって金属酸化物半導体多孔質層のフィラー同士の結合を促進させるには、樹脂フィルム基材が変質、変形する温度（例えば、樹脂フィルム基材の耐熱温度以上）の加熱を金属酸化物半導体多孔質層に対して行う必要があるため、加熱により樹脂フィルム基材が変形、変質してしまう傾向にあるからである。具体的な加熱温度の範囲は、典型的には、４０℃以上１０００℃以下であり、好ましくは、２００℃以上５５０℃以下である。処理時間は、特に制限はないが、通常は１秒以上１０時間以下である。具体的な冷却の温度範囲は、典型的には１５０℃以下であり、好ましくは０℃以下である。電磁波照射による加熱では、瞬時に高温に加熱することが可能であるので、焼成炉やオーブンによる加熱に比べて、処理時間を短縮化できる。
　支持体６の冷却は、銅板等の冷却板、冷却ロール等の冷却部材を支持体６の金属酸化物半導体多孔質層が形成されていない側の面（例えば、電磁波照射部位の裏面等）に密着させることにより行ってもよい。例えば、冷却板を用いる場合には、金属酸化物半導体多孔質層が形成された支持体６を冷却板上に載置する。このとき、支持体６の金属酸化物半導体多孔質層が形成されない側の面が、冷却板と密着する面となる。そして、金属酸化物半導体多孔質層に対して、電磁波照射すると共に、冷却板により、支持体６の金属酸化物半導体多孔質層が形成されない側の面側から、支持体６を冷却する。例えば、冷却ロールを用いる場合には、冷却ロールの表面を、支持体の金属酸化物半導体多孔質層が形成されていない側の一主面と密着させ、これにより、支持体６の冷却が行われる。
　例えば、冷却板、冷却ロール等の冷却部材の内部には、水等の冷媒が循環されており、これにより、適切な冷却温度（例えば、樹脂フィルム基材が熱により変質、変形する温度未満に冷却可能な温度）に冷却部材の温度が調整される。冷却部材に金属酸化物半導体多孔質層の形成された支持体６を接触させる場合、冷却部材と支持体６との間の隙間が、少ないことが好ましい。冷却部材と支持体６とを隙間のない様に接触させて十分に放熱させることで、樹脂フィルム基材が変質および変形することを防ぐことができる。支持体６と冷却部材との間に、エタノール、メタノール等の凝固点の低い液体等の不凍液、ゲル状の冷却材または不凍性を持つシート等の冷却媒層を設けて、支持体６と冷却部材との間の隙間が全く無い状態にして、支持体６を冷却するようにしてもよい。なお、冷却部材は、冷却板、冷却ロールに限定されるものではなく、支持体６を適切な温度に冷却する冷却機能を有するものであればよい。
　支持体６として、樹脂フィルム基材の一主面に透明導電層が形成された透明導電層付き樹脂フィルムを用い、その透明導電層の材料としてＩＴＯを用いる場合、電磁波照射を行う雰囲気を、酸素を含まない雰囲気にすることが好ましい。なぜなら、ＩＴＯは大気中等の酸素を含んだ雰囲気中で高温（例えば、約２５０℃以上）で処理すると酸素を取り込むことにより酸素欠損がなくなりキャリアが減少してしまうため、抵抗値が増大してしまうという課題があるからである。
　例えば、酸素を含まない雰囲気としては、窒素、アルゴン、ヘリウム等の不活性ガス雰囲気や、真空中、水素雰囲気等が挙げられるが、これに限定するものではない。なお、ＦＴＯに関しては、酸素欠損の箇所は、フッ素でドープされているため、大気中高温での熱処理をしても導電率への影響は少ない。
　電磁波照射後、金属酸化物半導体多孔質層の実表面積を増大させたり、金属酸化物半導体微粒子２および３間のネッキングを高めたりする目的で、四塩化チタンやチタンアルコキシド等の金属塩や金属アルコキシドを用いてネッキング処理を行ってもよい。また、金属酸化物半導体多孔質層内に残留する有機物や未反応物を溶媒等で洗浄除去してもよい。
　支持体６の材料としてプラスチック材料を用いる場合、加熱加圧処理、例えばカレンダー処理によって半導体電極層１を支持体６に圧着する処理を行ってもよい。
　支持体６がガラスや金属（金属メッシュ、金属シート、金属膜等）等の高温焼成に耐えられる基材である場合、電磁波照射をする際に基材を冷却しなくてもよい。この場合、焼成処理の代わりに、電磁波照射処理を行ってもよい。焼成処理を電磁波照射で代わりに行うことにより、乾燥・焼成に関して省プロセス化になる。
　但し、この場合においても、支持体６が導電層を有する場合、その導電層の材質に応じて雰囲気を変える必要がある。すなわち、支持体６が透明導電層を有する場合において、透明導電層がＩＴＯ等の酸素雰囲気で焼成を行えないものである場合、電磁波照射を行う雰囲気を、酸素を含まない雰囲気にする必要がある。例えば、酸素を含まない雰囲気としては、窒素、アルゴン、ヘリウム等の不活性ガス雰囲気や、真空中、水素雰囲気等が挙げられるが、これに限定するものではない。
＜金属酸化物半導体多孔質層の加圧処理＞
　電磁波照射処理の他、カレンダー処理、プレス処理等の半導体微粒子層（金属酸化物半導体多孔質層）のフィラー同士の物理的な接触を高める処理を行ってもよい。これにより、例えば、色素増感型太陽電池のエネルギー変換効率を向上させることができる。半導体微粒子層の加圧処理は、電磁波照射処理による照射加熱の前若しくは後、または前および後に行ってもよい。
　カレンダー処理またはプレス処理により、半導体微粒子間の接触が促進される、半導体微粒子層の透明性が上がる、半導体微粒子層厚が薄くなる。その結果、例えば、樹脂フィルム基材またはガラス基材を用いた色素増感型太陽電池において、変換効率が向上する。カレンダー処理の場合、プレスロールの温度は１５０℃未満、バックロールの温度は１５０℃未満、線圧は０℃超５００ｋｇ／ｃｍ以下とすることが好ましい。上記温度以上である場合、半導体微粒子フィルムが熱負け等により変形してしまう傾向にある。プレスの場合、ガラスの耐えられる温度以下での範囲で、加重は１５ｔ／２５ｍｍ２以下が好ましい。これを超えた加重である場合、半導体微粒子が密になり過ぎてしまい、ポーラス構造としての空孔が無くなり、色素吸着や電解液の染み込みが困難になるため、性能が劣化する傾向にある。カレンダー処理またはプレス処理等の加圧処理は２回以上行ってもよい。
　半導体電極層および半導体電極層の製造方法について、さらに詳細に説明する。上述した半導体電極層１または２３を色素増感型太陽電池に用いる場合には、下記の通りである。
　半導体電極層１または２３の厚さは１μｍ以上３０μｍ以下であるのがよい。厚さが１μｍ未満である場合、十分な光電変換効率が得られない。厚さが厚いほど光電変換効率は向上するが、厚さが３０μｍをこえると、膜厚の増加による光電変換効率向上の効果が乏しくなる。従って、厚さは３０μｍ以下が好ましい。
　金属酸化物半導体微粒子２および３の材料として、各種の金属酸化物半導体や、ペロブスカイト構造を有する化合物などを用いることができる。この際、金属酸化物半導体微粒子２および３の材料が、光励起下で伝導帯電子がキャリアとなり、アノード電流を生じるｎ型半導体材料であることが好ましい。このような半導体材料は、具体的に例示すると、ＴｉＯ２、ＺｎＯ、ＷＯ３、Ｎｂ２Ｏ５、ＳｒＴｉＯ３、およびＳｎＯ２などであり、これらの中でＴｉＯ２がとくに好ましい。ただし、金属酸化物半導体微粒子２および３の材料はこれらに限定されるものではない。また、これらの材料を２種類以上混合して用いることもできる。
　粒状の金属酸化物半導体微粒子２の粒子径は、可視光を透過させ、比表面積を大きくするためには、一次粒子の平均粒子径が１~１００ｎｍであるのが好ましい（ただし、この場合、金属酸化物半導体多孔質層にクラックが発生し、金属酸化物半導体微粒子間の導電性が低下し、この金属酸化物半導体多孔質層を用いた色素増感型太陽電池の光電変換性能が低下することがある。このような場合については、後述の実施の形態２参照。）。金属酸化物半導体微粒子２および３は、市販品を用いてもよいし、また、塩化物やアルコキシドなどをゾル−ゲル法などの公知の方法で加水分解処理または水熱処理するなどして、所定の粒径のものを作製してもよい。
　金属酸化物半導体微粒子２および３の材料として酸化チタンを用いる場合、その結晶型はルチル型、アナターゼ型、およびブルッカイト型の中から選択される１種類でよく、２種類以上の混合物でもよい。市販品としては、一次粒子の平均粒子径が１~１００ｎｍである粒状の金属酸化物半導体微粒子２として、例えば、デグサ社製のＰ２５およびＰ９０（以上、商品名）、石原産業（株）製のＳＴ−０１およびＳＴ−２１（以上、商品名）、昭和電工（株）製のスーパータイタニアＦ−１、Ｆ−２、Ｆ−３、Ｆ−４、Ｆ−５、およびＦ−６（以上、商品名）、堺化学工業（株）製のＳＳＰ−２５、ＳＳＰ−２０、ＳＳＰ−Ｍ、およびＳＴＲシリーズ（以上、商品名）、テイカ（株）製のＭＴ−１５０Ａ、ＭＴ−５００Ｂ、ＭＴ−６００Ｂ、ＭＴ−７００Ｂ、ＡＭＴ−１００、ＡＭＴ−６００、ＴＫＰ−１０１、およびＴＫＰ−１０２（以上、商品名）、シーアイ化成（株）製のＮａｎｏＴｅｋ　Ｐｏｗｄｅｒシリーズ（商品名）などを用いることができる。
　また、針状の金属酸化物半導体微粒子３として、石原産業（株）製のＦＴＬ−１００、ＦＴＬ−１１０、ＦＴＬ−２００、ＦＴＬ−３００、ＦＴ−１０００、ＦＴ−２０００、ＦＴ−３０００、ＦＳ−１０Ｐ、およびＦＳ−１０Ｄ（以上、商品名）などを用いることができる。
　金属酸化物半導体微粒子２および３の材料として酸化亜鉛を用いる場合、市販品としては、粒状の金属酸化物半導体微粒子２として、例えば、テイカ（株）製のＭＺ−３００およびＭＺ−５００（以上、商品名）、石原産業（株）製のＦＺＯ−５０（商品名）、シーアイ化成（株）製のＮａｎｏＴｅｋ　Ｐｏｗｄｅｒシリーズ（商品名）、堺化学工業（株）製のＦＩＮＥＸシリーズ（商品名）、ハクスイテック（株）製のＦ−１、Ｆ−２、Ｆ−３、Ｐａｚｅｔ　ＣＫ、およびＰａｚｅｔ　ＧＫ−４０（以上、商品名）などを用いることができる。また、針状の金属酸化物半導体微粒子３として、（株）アムテックのパナテトラ（商品名）などを用いることができる。
　金属酸化物半導体微粒子２および３の材料として酸化スズを用いる場合、市販品としては、粒状の金属酸化物半導体微粒子２として、例えば、Ｊｏｈｎｓｏｎ　Ｍａｔｔｈｅｙ（株）製の平均粒子径１５ｎｍのものや、シーアイ化成（株）製のＮａｎｏＴｅｋ　Ｐｏｗｄｅｒシリーズ（商品名）などを用いることができる。
　半導体電極層の第２の構成例において、粒状の金属酸化物半導体微粒子２Ａとして市販品を用いる場合、上述した一次粒子の平均粒子径が１ｎｍ以上１００ｎｍ以下である市販品を用いることができる。粒状の金属酸化物半導体微粒子２Ｂとして市販品を用いる場合、酸化チタン微粒子であれば、例えば、石原産業（株）製のＰＴ−３０１、ＣＲ−ＥＬ、ＥＴ−５００Ｗ、ＥＴ−６００Ｗ、およびＳＴ−４１（以上、商品名）、昭和電工（株）製のＧ−１、Ｇ−２、およびＦ−１０（以上、商品名）、テイカ（株）製ＪＲ（商品名）、富士チタン工業（株）製ＴＡ−１００、ＴＡ−２００、ＴＡ−３００、ＴＡ−５００（以上、商品名）等を用いることができる。また、酸化亜鉛微粒子であれば、例えば、堺化学工業（株）製のＬＰＺＩＮＣ−２およびＬＰＺＩＮＣ−５（以上、商品名）等を用いることができる。また、塩化物やアルコキシド等をゾル−ゲル法等の公知の方法で加水分解処理または水熱処理する等して、所定の粒径のものを作製してもよい。
　なお、上記の金属酸化物半導体微粒子２および３の材料は、適宜混合して用いることも可能である。
　第１の化合物として塩またはアルコキシドのうち、有機溶媒に溶解させることができるものを用いることができる。上記第１の化合物は、Ｔｉ、Ａｌ、Ｓｉ、Ｖ、Ｚｒ、Ｎｂ、およびＴａなどの、少なくとも一種の元素の化合物であるのがよい。また、多くの場合、上記元素が金属酸化物半導体微粒子２を構成している金属元素と同一の元素であり、第１の化合物から生成する第１の酸化物と、金属酸化物半導体微粒子２を構成している金属酸化物とが同種の酸化物であるのがよい。このようであると金属酸化物半導体微粒子２と第１酸化物層４との密着性が最良になると期待できる。
　また、第１の化合物として、金属酸化物半導体微粒子２及び／又は有機溶媒に通常含まれる水分によって室温で加水分解される第１の化合物を用いるのがよい。この場合、前述したように、塗液中で第１の化合物の加水分解が始まり、生成した第１の酸化物によって金属酸化物半導体微粒子２間が連結されていくので、微粒子２間の強固なネットワークが形成されやすい。
　塩としては、硝酸塩、硫酸塩、酢酸塩、シュウ酸塩、ハロゲン化物などのうち、溶媒に溶解するものを用いることができる。具体的には、ＴｉＯＳＯ４、Ｚｒ（ＣＨ３ＣＯＯ）２Ｏ、Ｚｒ（ＣＨ３ＣＯＯ）４、Ａｌ（ＮＯ３）３、Ａｌ（ＣＨ３ＣＯＯ）３、Ａｌ２（ＳＯ４）３、ＴｉＣｌ４、ＡｌＣｌ３、Ｔｉ（Ｃ２Ｏ４）２、Ｚｒ（Ｃ２Ｏ４）２、およびＡｌ２（Ｃ２Ｏ４）３などを用いることができる。
　また、用いることのできるアルコキシドは、下記の一般式のように表すことができる。
アルコキシドの一般式：
Figure JPOXMLDOC01-appb-C000001
 　上記一般式で、金属アルコキシドは、モノマー（ｍ＝０）、オリゴマー（ｍ＝１~１０）、およびポリマー（ｍ＞１０）のいずれでもよく、２種類以上を混合して用いることもできる。アルコキシ基としては、メトキシ基（ｎ＝１）、エトキシ基（ｎ＝２）、ｎ−プロポキシ基、ｉ−プロポキシ基（以上、ｎ＝３）、ｎ−ブトキシ基、ｉ−ブトキシ基、ｓｅｃ−ブトキシ基、ｔｅｒｔ−ブトキシ基（以上、ｎ＝４）や、２−エチルヘキソキシ基、その他の低級および高級アルコール由来のアルコキシ基を用いることができる。また、アルコキシドがアセチルアセトンなどのβ−ジケトン類で修飾されていてもよい。アルコキシ基の一部がヒドロキシ基で置換されていてもよい。
　市販品としては、例えば、下記のものを用いることができる。すなわち、日本曹達株式会社製のＡ−１、Ｂ−１、ＴＯＴ、ＴＯＧ、Ｔ−５０、Ｔ−６０、Ａ−１０、Ｂ−２、Ｂ−４、Ｂ−７、Ｂ−１０、ＴＢＳＴＡ、ＤＰＳＴＡ−２５、Ｓ−１５１、Ｓ−１５２、Ｓ−１８１、ＴＡＴ、およびＴＬＡ−Ａ−５０（以上、商品名）、三菱ガス化学株式会社製のＴＰＴ、ＴＢＴ、ＤＢＴ、ＴＳＴ、ＴＥＡＴ、ＴＡＡ、ＴＥＡＡ、ＴＬＡ、およびＯＧＴ（以上、商品名）、味の素ファインテクノ株式会社製のＫＲ　ＴＴＳ、ＫＲ　４６Ｂ、ＫＲ　５５、ＫＲ　４１Ｂ、ＫＲ　３８Ｓ、ＫＲ　１３８Ｓ、ＫＲ　２３８Ｓ、３３８Ｘ、ＫＲ　４４、ＫＲ　９ＳＡ、ＫＲ　ＥＴ、およびＡＬ−Ｍ（以上、商品名）、マツモトファインケミカル株式会社製のＴＡ−１０、ＴＡ−２５、ＴＡ−２２、ＴＡ−３０、ＴＣ−１００、ＴＣ−４０１、ＴＣ−２００、ＴＣ−７５０、ＴＣ−４００、ＴＣ−３００、ＴＣ−３１０、ＴＣ−３１５、ＴＰＨＳ、ＺＡ−４０、ＺＡ−６５、ＺＣ−１５０、ＺＣ−５４０、ＺＣ−５７０、ＺＣ−５８０、ＺＣ−７００、ＺＢ−３２０、およびＺＢ−１２６（以上、商品名）、コルコート株式会社製のエチルシリケート２８、エチルシリケート２８Ｐ、Ｎ−プロピルシリケート、Ｎ−ブチルシリケート、ＭＣＳ−１８、メチルシリケート５１、メチルシリケート５３Ａ、エチルシリケート４０、エチルシリケート４８、ＥＭＳ−４８５、ＳＳ−１０１、ＨＡＳ−６、ＨＡＳ−１、ＨＡＳ−１０、ＳＳ−Ｃ１、コルコートＰ、コルコートＮ−１０３Ｘ、およびマグネシウムエチラート（以上、商品名）を用いることができる。
　金属酸化物半導体微粒子２および３の材料として酸化チタンを用いる場合、第１の化合物としては、例えば、四塩化チタンＴｉＣｌ４、硫酸チタニアＴｉＯＳＯ４、テトラメトキシチタンＴｉ（ＯＣＨ３）４、テトラプロポキシチタンＴｉ（ＯＣＨ２ＣＨ２ＣＨ３）４、テトラブトキシチタンＴｉ（ＯＣＨ２ＣＨ２ＣＨ２ＣＨ３）４、テトラペントキシチタンＴｉ（ＯＣＨ２ＣＨ２ＣＨ２ＣＨ２ＣＨ３）４、ブトキシチタンダイマー、ブトキシチタンオリゴマー、ブトキシチタンポリマー、テトラメトキシジルコニウムＺｒ（ＯＣＨ３）４、テトラエトキシジルコニウムＺｒ（ＯＣＨ２ＣＨ３）４、テトラプロポキシジルコニウムＺｒ（ＯＣＨ２ＣＨ２ＣＨ３）４、テトラブトキシジルコニウムＺｒ（ＯＣＨ２ＣＨ２ＣＨ２ＣＨ３）４、トリメトキシアルミニウムＡｌ（ＯＣＨ３）３、トリエトキシアルミニウムＡｌ（ＯＣＨ２ＣＨ３）３、トリプロポキシアルミニウムＡｌ（ＯＣＨ２ＣＨ２ＣＨ３）３、トリブトキシアルミニウムＡｌ（ＯＣＨ２ＣＨ２ＣＨ２ＣＨ２ＣＨ３）３などを好ましく用いることができる。
　一方、第２の化合物としては、Ｓｉ、Ｂ、Ａｌ、およびＺｒなどのアルコキシドを用い、第２酸化物層５を形成する酸化物が、ＳｉＯ２、Ｂ２Ｏ３、Ａｌ２Ｏ３、およびＺｒＯ２などの硬度の高い酸化物であるのがよい。
　金属酸化物半導体微粒子２および３の材料として酸化チタンを用いる場合、第２の化合物としては、例えば、ジメチルジメトキシシランＳｉ（ＣＨ３）２（ＯＣＨ３）２、ジメチルジエトキシシランＳｉ（ＣＨ３）２（ＯＣＨ２ＣＨ３）２、メチルトリメトキシシランＳｉ（ＣＨ３）（ＯＣＨ３）３、メチルトリエトキシシランＳｉ（ＣＨ３）（ＯＣＨ２ＣＨ３）３、テトラメトキシシランＳｉ（ＯＣＨ３）４、テトラエトキシシランＳｉ（ＯＣＨ２ＣＨ３）４、テトラプロポキシシランＳｉ（ＯＣＨ２ＣＨ２ＣＨ３）４、テトラブトキシシランＳｉ（ＯＣＨ２ＣＨ２ＣＨ２ＣＨ３）４、エトキシシランダイマー、エトキシシランオリゴマー、エトキシシランポリマー、トリメトキシボランＢ（ＯＣＨ３）３、トリエトキシボランＢ（ＯＣＨ２ＣＨ３）３、トリイソプロポキシボランＢ（ＯＣＨ（ＣＨ３）ＣＨ３）３などを好ましく用いることができる。
　溶媒としては、第１の化合物および第２の化合物を溶解させ、金属酸化物半導体微粒子２および３を分散させることができるものを用いる。例えば、メタノール、エタノール、１−プロパノール、２−プロパノール（イソプロピルアルコール）、１−ブタノール、２−ブタノール（イソブチルアルコール）、３−メチル−２−プロパノール（ｓｅｃ−ブチルアルコール）、および２−メチル−２−プロパノール（ｔｅｒｔ−ブチルアルコール）などのアルコール、シクロヘキサノンおよびシクロペンタノンなどのケトン、ヘキサンなどの炭化水素溶媒、ジメチルホルムアミド（ＤＭＦ）などのアミド、ジメチルスルホキシド（ＤＭＳＯ）などのスルホキシドなどから選択される少なくとも１種類以上を用いることができる。
　塗液層の表面における乾燥むらを抑えるため、高沸点溶媒を添加して、溶媒の蒸発速度を制御することもできる。そのような高沸点溶媒として、例えば、ブチルセロソルブ、ジアセトンアルコール、ブチルトリグリコール、プロピレングリコールモノメチルエーテル、プロピレングリコールモノエチルエーテル、エチレングリコールモノエチルエーテル、エチレングリコールモノプロピルエーテル、エチレングリコールモノイソプロピルエーテル、ジエチレングリコールモノブチルエーテル、ジエチレングリコールモノエチルエーテル、ジエチレングリコールモノメチルエーテルジエチレングリコールジエチルエーテル、ジプロピレングリコールモノメチルエーテル、トリプロピレングリコールモノメチルエーテル、プロピレングリコールモノブチルエーテル、プロピレングリコールイソプロピルエーテル、ジプロピレングリコールイソプロピルエーテル、トリプロピレングリコールイソプロピルエーテル、メチルグリコールなどを用いることができる。また、支持体６への塗布性や組成物のポットライフを向上させる目的で、必要に応じて界面活性剤、粘度調整剤、および分散剤などの添加剤を加えることができる。
＜ロールツーロールプロセス＞
　上述した半導体電極層の製造工程を、ロールツーロールプロセスにおいて行ってもよい。本開示の第１の実施の形態による半導体電極層の製造方法では、軽量、安価でフレキシブルなプラスチックフィルム等の樹脂フィルム基材のような、耐熱性の乏しい材料を支持体６に用いることが可能であり、ロールツーロールプロセスによって、さらに生産性よく安価に、半導体電極層を製造することが可能である。以下では、ロールツーロールプロセスにより、半導体電極層を製造する例について説明する。
　図３は、ロールツーロールプロセスにより半導体電極層を製造する例を説明するための略線図である。例えばロール状に巻かれたフィルム基材１６（図示省略）から、フィルム基材１６が供給され、巻き取りロール３７により巻き取られ、供給されたフィルム基材１６は矢印方向に走行される。
　走行するフィルム基材１６に対して、塗液の塗布、乾燥・焼成処理、カレンダー処理、電磁波処理が順次行われる。
　まず、ダイコータ等の塗布部４１により、ロール３１により案内されるフィルム基材１６の一主面に対して、予め調製された半導体微粒子を含む塗液を間欠塗布する。次に、焼成炉３２において、フィルム基材１６の一主面上に塗布された半導体微粒子層に対して、塗布液の乾燥およびネッキング処理のための焼成処理が行われる。焼成温度は、フィルム基材１６を構成する材料のガラス転移点以下であることが好ましく、典型的には、４０℃以上２００℃以下であることが好ましい。また、焼成時間に特に制限はないが、通常、３０秒間以上１０時間以下程度である。このとき、ネッキングが促進するが、低温で焼成しているため、十分ではない。後述の電磁波処理により、さらにネッキングを促進し、特性を向上させることができる。
　次に、バックロール３４およびプレスロール３５により、カレンダー処理され、これにより、半導体微粒子間の接触が促進される、金属酸化物半導体多孔質層３３の透明性が上がる、金属酸化物半導体多孔質層３３の厚さが薄くなる。その結果、例えば、色素増感型太陽電池の光電変換効率を向上できる。プレスロール３５の温度は、例えば、１５０℃未満、バックロール３４の温度は、１５０℃未満、線圧は０ｋｇ／ｃｍ超５００ｋｇ／ｃｍ以下とすることが好ましい。プレスロール３５およびバックロール３４の温度が、上記温度以上である場合、フィルム基材１６が熱負け等により変形してしまう傾向にある。
　次に、電磁波処理部４０により、金属酸化物半導体多孔質層３３に対して電磁波が照射され、金属酸化物半導体多孔質層３３が瞬時に高温に加熱される。図４に示すように、電磁波処理部４０は、フィルム基材１６に形成された金属酸化物半導体多孔質層３３に対して、赤外線を照射し加熱する赤外線加熱ランプ等の電磁波照射部４３と、フィルム基材１６の金属酸化物半導体多孔質層３３が形成されていない一主面を冷却する冷却ロール３６とを備える。電磁波照射部４３により、金属酸化物半導体多孔質層３３に対して、赤外線を短時間照射し、半導体微粒子同士のネッキングを促進する。赤外線照射による加熱では、瞬時に高温で加熱が可能である、フィルム基材１６を冷却しながらの金属酸化物半導体多孔質に対する赤外線照射を可能とする、大気中での処理が可能である等の利点を有する。
　冷却ロール３６は、例えば、冷却ロール３６内で、エチレングリコール等の不凍液等からなる冷媒が循環されており、例えば、０℃以下の温度とされている。冷却ロール３６の表面は、フィルム基材１６の半導体微粒子層が形成されていない側の一主面と密着しており、これにより、フィルム基材１６の冷却が行われる。図４に示すように、例えば、この冷却ロール３６の表面にエタノール等の不凍液層４７を設けることが好ましい。これにより、冷却ロール３６の表面と、樹脂フィルム基材１６の半導体微粒子層が形成されていない側の一主面との密着性を向上させることができ、フィルム基材１６に対する冷却能を向上できるからである。
　フィルム基材１６として、透明導電層付き樹脂フィルム基材を用い、その透明導電層がＩＴＯ層である場合には、電磁波処理を行う雰囲気を、酸素を含まない雰囲気にすることが好ましい。酸素を含まない雰囲気としては、不活性ガス雰囲気、真空または水素雰囲気等が挙げられる。ＩＴＯは、大気中等の酸素を含有した雰囲気中での電磁波処理では、酸素を取り込むことにより酸素欠損がなくなりキャリアが減少してしまうため、抵抗値が増大してしまう傾向にある。そこで、ＩＴＯ等の酸素雰囲気で焼成を行えない導電層を処理する場合、酸素を含まない雰囲気にする必要がある。不活性ガスとしては、例えば、窒素ガス、アルゴンガス、ヘリウムガス等が挙げられる。例えば、図４に示すような、雰囲気制御可能なチャンバ４４内に不活性ガスを充満させ、この中で電磁波処理を行うようにしてもよく、また、不活性ガス等をフィルム基材１６に吹き付けるようにして、電磁波処理を行うようにしてもよい。例えば、大気雰囲気のような酸素を含む雰囲気中では、ＩＴＯは２５０℃以上に加熱されると抵抗率が上昇してしまう。これは、酸素欠損が埋まってしまいキャリアが減少することが原因である。したがって、酸素を含まない雰囲気中で、電磁波処理を行うことが好ましい。
（色素増感型太陽電池）
　本開示の第１の実施の形態の半導体電極層の製造方法により得た半導体電極層を用いた電気化学装置の例として、色素増感型太陽電池として構成された電気化学装置について説明する。
　図５は、色素増感型太陽電池６０の構造の一例を示す断面図である。色素増感型太陽電池６０は、主として、透明基板６１、透明導電層（負極集電体）６２、光増感色素を保持した半導体電極層（負極）６３、電解質層６４、対向電極（正極）６５、対向基板６６、および封止材６７等で構成されている。
　半導体電極層６３は、上述した酸化チタンＴｉＯ２等の半導体電極層（金属酸化物半導体多孔質層）１または２１からなり、金属酸化物半導体微粒子２および３等の表面に光増感色素を保持している。色素増感型太陽電池６０は、半導体電極層６３を電極として有しているので、フレキシブルなプラスチックフィルム等を支持体として用いて、軽量、安価に、生産性よく製造可能な電気化学装置である。しかも、半導体電極層６３は、針状の金属酸化物半導体微粒子３を含有していない半導体電極層に比べて導電性が向上しているので、色素増感型太陽電池を構成した場合の光電変換性能が向上する。さらに、針状の金属酸化物半導体微粒子３は、光拡散機能を有する。このため、入射光の利用率が向上し、これによっても光電変換性能が向上する。
　その他は、従来の色素増感型太陽電池と同様である。すなわち、透明基板６１は、ガラス板、またはＰＥＮやＰＥＴ等のプラスチックフィルム等からなる。透明導電層（負極集電体）６２はＩＴＯやＦＴＯ等からなり、透明基板６１の上に設けられている。電解質層６４は、Ｉ−／Ｉ３ −（三ヨウ化物イオンＩ３ −は、Ｉ２がヨウ化物イオンＩ−と結びついてイオンとして存在している化学種である。）等の酸化還元種（レドックス対）を含む電解液等で構成され、電解液が半導体電極層６３内に浸潤できるように、半導体電極層６３と対向電極６５との間に配置されている。対向電極６５は、下地層に積層された白金層や、カーボン層等からなり、対向基板６６の上に設けられている。対向基板６６はガラス板やプラスチックフィルム等からなる。
　色素増感型太陽電池６０は、光が入射すると、対向電極６５を正極、半導体電極層６３を負極とする電池として動作する。
　すなわち、透明基板６１および透明導電層６２を透過してきた光子を光増感色素が吸収すると、光増感色素中の電子が基底状態から励起状態へ励起される。励起状態の電子は、光増感色素と半導体電極層６３との間の電気的結合を介して、半導体電極層６３の伝導帯に取り出され、半導体電極層６３を通って透明導電層６２に到達する。
　一方、電子を失った光増感色素は、電解質層６４中の還元剤、例えばＩ−から下記の反応
　２Ｉ−→Ｉ２＋２ｅ−
　Ｉ２＋Ｉ−→Ｉ３ −
によって電子を受け取り、電解質層６４中に酸化剤、例えばＩ３ −を生成させる。生じた酸化剤は拡散によって対向電極６５に到達し、上記の反応の逆反応
　Ｉ３ −→Ｉ２＋Ｉ−
　Ｉ２＋２ｅ−→２Ｉ−
によって対向電極６５から電子を受け取り、もとの還元剤に還元される。
　透明導電層６２から外部回路へ流れ出した電子は、外部回路で電気的仕事をした後、対向電極６５に戻る。このようにして、光増感色素にも電解質層６４にも何の変化も残さず、光エネルギーが電気エネルギーに変換される。
　色素増感型太陽電池６０を作製するには、透明基板６１に設けられた透明導電層６２上に、上記で説明した半導体電極層の製造方法により、半導体電極層１または２１を形成する。次に、半導体電極層１または２１に光増感色素を吸着させ、半導体電極層１または２１を形成する。色素を吸着させる方法に特に制限はないが、例えば、色素分子を溶解させた溶液を調製し、半導体電極層１または２１が形成された透明基板６１を色素溶液に浸漬するか、または、半導体電極層１または２１に色素溶液を塗布、噴霧、または滴下するか等して、半導体電極層１または２１に色素溶液をしみこませた後、溶媒を蒸発させる。次に、半導体電極層６３と対向電極６５とが対向するように透明基板６１と対向基板６６とを配置して、封止材６７を介して貼り合わせる。最後に、電解液を注入して電解質層６４を形成する。
　半導体電極層６３は、多くの光増感色素を吸着することができるように、多孔質層内部の空孔に面する微粒子表面も含めた実表面積の大きいものが好ましく、半導体電極層６３の実表面積は、その外側表面の面積（投影面積）に対して１０倍以上であることが好ましく、さらに１００倍以上であることが好ましい。
　一般に、半導体電極層６３の厚さが増し、単位投影面積当たりに含まれる金属酸化物半導体微粒子２および３の数が増加するほど、実表面積が増加し、単位投影面積あたりに保持できる色素量が増加するので、入射光に対する光吸収率が高くなる。一方、半導体電極層６３の厚さが増加すると、光増感色素から半導体電極層６３に移行した電子が透明導電層６２に達するまでに拡散する距離が増加するため、半導体電極層６３内での電荷再結合による電子のロスも大きくなる。従って、半導体電極層６３には好ましい厚さが存在するが、一般的には０．１μｍ以上１００μｍ以下であり、１μｍ以上３０μｍ以下であるのがより好ましい。
　色素増感型太陽電池６０は、半導体電極層６３以外の部材については、従来の色素増感型太陽電池と同様である。以下、要点を説明する。
　半導体電極層６３に保持させる光増感色素としては、増感作用を示すものであれば特に制限はないが、例えば、ローダミンＢやローズベンガルやエオシンやエリスロシン等のキサンテン系色素、メロシアニンやキノシアニンやクリプトシアニン等のシアニン系色素、フェノサフラニンやカブリブルーやチオシンやメチレンブルー等の塩基性染料、その他のアゾ色素、クロロフィルや亜鉛ポルフィリンやマグネシウムポルフィリン等のポルフィリン系化合物、フタロシアニン系化合物、クマリン系化合物、ルテニウムＲｕのビピリジン錯体やテルピリジン錯体、アントラキノン系色素、多環キノン系色素、スクアリリウム系色素等が挙げられる。中でも、配位子がピリジン環を有するルテニウムＲｕのビピリジン錯体は、量子収率が高く、光増感色素として好ましい。ただし、光増感色素はこれに限定されるものではなく、単独で、もしくは２種類以上を混合して用いることができる。
　電解質層６４としては、電解液、またはゲル状あるいは固体状の電解質が使用可能である。電解質としては、酸化還元系（レドックス対）を含む溶液が挙げられ、具体的には、ヨウ素Ｉ２と金属ヨウ化物塩または有機ヨウ化物塩との組み合わせや、臭素Ｂｒ２と金属臭化物塩または有機臭化物塩との組み合わせを用いる。金属ハロゲン化物塩を構成するカチオンは、リチウムＬｉ＋、ナトリウムＮａ＋、カリウムＫ＋、セシウムＣｓ＋、マグネシウムＭｇ２＋、およびカルシウムＣａ２＋等であり、有機ハロゲン化物塩を構成するカチオンは、テトラアルキルアンモニウムイオン類、ピリジニウムイオン類、イミダゾリウムイオン類等の第４級アンモニウムイオンが好適であるが、これらに限定されるものではなく、単独もしくは２種類以上を混合して用いることができる。
　上記の中でも特に、ヨウ素Ｉ２と、ヨウ化リチウムＬｉＩ、ヨウ化ナトリウムＮａＩ、またはイミダゾリウムヨーダイド等の第４級アンモニウム化合物とを組み合わせた電解質が好適である。電解液における電解質塩の濃度は０．０５Ｍ以上５Ｍ以下が好ましく、さらに好ましくは０．１Ｍ以上３Ｍ以下である。ヨウ素Ｉ２または臭素Ｂｒ２の濃度は０．０００５Ｍ以上１Ｍ以下が好ましく、さらに好ましくは０．００５Ｍ以上０．５Ｍ以下である。また、開放電圧や短絡電流を向上させる目的で４−ｔｅｒｔ−ブチルピリジンやカルボン酸等各種添加剤を加えることもできる。
　電解液を構成する溶媒として、水、アルコール類、エーテル類、エステル類、炭酸エステル類、ラクトン類、カルボン酸エステル類、リン酸トリエステル類、複素環化合物類、ニトリル類、ケトン類、アミド類、ニトロメタン、ハロゲン化炭化水素、ジメチルスルホキシド、スルフォラン、Ｎ−メチルピロリドン、１，３−ジメチルイミダゾリジノン、３−メチルオキサゾリジノン、および炭化水素等が挙げられるが、これらに限定されるものではなく、単独で、もしくは２種類以上を混合して用いることができる。また、溶媒としてテトラアルキル系、ピリジニウム系、イミダゾリウム系第４級アンモニウム塩の室温イオン性液体を用いることも可能である。
　色素増感型太陽電池６０からの電解液の漏液や、電解液を構成する溶媒の揮発を減少させる目的で、電解質構成物にゲル化剤、ポリマー、架橋モノマー、または各種形状の金属酸化物半導体微粒子（繊維）等を溶解または分散させて混合し、ゲル状電解質として用いることも可能である。ゲル化材料と電解質構成物の比率は、電解質構成物が多ければイオン導電率は高くなるが、機械的強度は低下する。逆に、電解質構成物が少なすぎると、機械的強度は大きいが、イオン導電率は低下する。
　電解液の注入方法に特に制限はないが、注入口に溶液を数滴垂らし、毛細管現象によって導入する方法が簡便である。また、必要に応じて、減圧もしくは加熱下で注入操作を行うこともできる。完全に溶液が注入された後、注入口に残った溶液を除去し、注入口を封止する。この封止方法にも特に制限はないが、必要であればガラス板やプラスチック基板を封止材で貼り付けて封止することもできる。
　また、電解質が、ポリマー等を用いてゲル化された電解質や、全固体型の電解質である場合、電解質と可塑剤とを含むポリマー溶液を、半導体電極層６３の上にキャスト法等によって塗布する。その後、可塑剤を揮発させ、完全に除去した後、上記と同様に封止材によって封止する。この封止は、真空シーラー等を用いて、不活性ガス雰囲気下、もしくは減圧中で行うことが好ましい。封止を行った後、電解質層６４の電解液が半導体電極層６３に十分に浸透するように、必要に応じて加熱、加圧の操作を行うことも可能である。
２．第２の実施の形態
　本開示の第２の実施の形態による酸化物半導体層の製造方法について説明する。本開示の第２の実施の形態による酸化物半導体層の製造方法は、例えば、プラスチックフィルム等の樹脂フィルム基材に形成された透明酸化物半導体層の製造方法である。
　まず、本開示の理解を容易にするため、この透明酸化物半導体層の製造方法により得た、透明酸化物半導体層付フィルムの構成について説明する。透明酸化物半導体層付フィルムは、図６に示すように、基材フィルム８６と、基材フィルム８６の一主面上に形成された透明酸化物半導体層８１とを有する。
（透明酸化物半導体層）
　透明酸化物半導体層８１の材料としては、公知のものを使用可能であり、具体的にはＩＴＯ、ＦＴＯ、アンチモンがドープされた酸化スズ（ＡＴＯ）、酸化スズ、酸化亜鉛、インジウム・亜鉛複合酸化物（ＩＺＯ）等が挙げられるが、これらに限定されるものではない。透明酸化物半導体層８１は、これらの材料の単層膜でも、積層膜でもよく、２種類以上の材料を組み合わせて用いることもできる。
（基材フィルム）
　基材フィルム８６としては、トリアセチルセルロース（ＴＡＣ）、ポリエチレンテレフタラート（ＰＥＴ）、ポリエチレンナフタラート（ＰＥＮ）、ポリエステル（ＴＰＥＥ）、ポリイミド（ＰＩ）、ポリアミド（ＰＡ）、アラミド、ポリエチレン（ＰＥ）、ポリアクリレート、ポリエーテルスルホン、ポリスルホン、ポリプロピレン（ＰＰ）、ジアセチルセルロース、ポリ塩化ビニル、アクリル樹脂（ＰＭＭＡ）、ポリカーボネート（ＰＣ）、エポキシ樹脂、尿素樹脂、ウレタン樹脂、メラミン樹脂、およびシクロオレフィンポリマー樹脂（ＣＯＰ）等の高分子材料からなる透明プラスチックフィルム等の樹脂フィルム基材を用いることができる。
　次に、上述した透明酸化物半導体層８１の製造方法について説明する。
＜透明酸化物半導体層の形成＞
　基材フィルム８６の一主面上に、透明酸化物半導体層８１を、例えば、ＰＶＤ（Ｐｈｙｓｉｃａｌ　Ｖａｐｏｒ　Ｄｅｐｏｓｉｔｉｏｎ：物理気相成長）法またはＣＶＤ（Ｃｈｅｍｉｃａｌ　Ｖａｐｏｒ　Ｄｅｐｏｓｉｔｉｏｎ：化学気相成長）法等の気相法により形成できる。また、電気めっき、無電界めっき、塗布法、ゾル−ゲル法等の液相法により形成できる。また、ＳＰＥ（固相エピタキシー）法、ＬＢ（Ｌａｎｇｍｕｉｒ−Ｂｌｏｄｇｅｔｔ：ラングミュアーブロジェット）法等の固相法により形成することができる。
＜電磁波処理＞
　透明酸化物半導体層８１を形成した後、透明導電粒子である透明酸化物半導体粒子のネッキング促進のため、電磁波処理を行う。基材フィルム８６の材料として、フィルム材料等の軟化点の低い基材である、プラスチック材料を用いているため、基材フィルム８６を冷却しながら電磁波照射することにより、基材フィルム８６に損傷を与えることなくネッキング促進による低抵抗化が可能となる。
　電磁波には、赤外線、紫外線、可視光線等がある。その他の照射タイプの処理として、マイクロ波処理、フレーム処理、大気中プラズマ処理、真空中プラズマ処理、コロナ処理、誘導加熱処理等が挙げられ、これらの方法を用いてもよい。
　フィルムが変質、変形する温度以上の加熱を透明酸化物半導体層８１に対して行う場合には、加熱によりフィルムの温度が、フィルムが変質、変形する温度以上になることを抑制するために、支持体（フィルム）を冷却しながら処理を行うことが好ましい。
　支持体の冷却は、銅板等の冷却板、冷却ロール等の冷却部材を基材フィルム８６の透明酸化物半導体層８１が形成されていない側の面に密着させることにより行ってもよい。例えば、冷却板を用いる場合には、透明酸化物半導体層８１が形成された基材フィルム８６の冷却板上に載置する。このとき、基材フィルム８６の透明酸化物半導体層８１が形成されない側の面が、冷却板と密着する面となる。そして、透明酸化物半導体層８１に対して、電磁波照射すると共に、冷却板により、基材フィルム８６の半導体微粒子膜が形成されない側の面側から、基材フィルム８６を冷却する。
　例えば、冷却ロールを用いる場合には、冷却ロール３６の表面を、基材フィルム８６の透明酸化物半導体層８１が形成されていない側の一主面と密着させ、これにより、基材フィルム８６の冷却が行われる。冷却ロール３６は、例えば、冷却ロール３６の中で、エチレングリコール等の不凍液等からなる冷媒が循環されており、例えば、０℃以下の温度とされている。
　この冷却ロール３６の表面に、エタノール等の不凍液層４７を設けることが好ましい。これにより、冷却ロール３６の表面と、基材フィルム８６の透明酸化物半導体層８１が形成されていない側の一主面との密着性を向上させることができ、基材フィルム８６に対する冷却能を向上できるからである。
　透明酸化物半導体層８１としてＩＴＯを用いる場合には、電磁波処理を行う雰囲気を、酸素を含まない雰囲気とすることが好ましい。酸素を含まない雰囲気としては、不活性ガス雰囲気、真空または水素雰囲気等が挙げられる。透明酸化物半導体層８１として用いるＩＴＯは、大気中等の酸素を含有した雰囲気中での電磁波処理では、酸素を取り込むことにより酸素欠損がなくなりキャリアが減少してしまうため、抵抗値が増大してしまう傾向にある。そこで、透明酸化物半導体層８１としてＩＴＯを用いる場合に、電磁波処理による加熱を行う場合には、酸素を含まない雰囲気にする必要がある。不活性ガスとしては、例えば、窒素ガス、アルゴンガス、ヘリウムガス等が挙げられる。例えば、雰囲気制御可能なチャンバ内で電磁波処理を行うことにより、電磁波処理を行う雰囲気の制御を行ってもよく、また、不活性ガス等を支持体に吹き付けるようにして、電磁波処理を行うことにより、電磁波処理を行う雰囲気の制御を行ってもよい。
　上述した透明酸化物半導体層８１の製造工程を、ロールツーロールプロセスにおいて行ってもよい。本開示の第２の実施の形態による透明酸化物半導体層８１の製造方法では、軽量、安価でフレキシブルなプラスチックフィルム等の、耐熱性の乏しい材料を支持体として用いることが可能であり、ロールツーロールプロセスによって、さらに生産性よく安価に、透明酸化物半導体層付きフィルムを製造することが可能である。 Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The description will be given in the following order.
1. First Embodiment (First Example of Manufacturing Method of Oxide Semiconductor Layer)
2. Second Embodiment (Second Example of Manufacturing Method of Oxide Semiconductor Layer)
3. Other embodiment (modification)
1. First embodiment
A method for manufacturing an oxide semiconductor layer according to the first embodiment of the present disclosure will be described. The method for producing an oxide semiconductor layer according to the first embodiment of the present disclosure is typically a method for producing a semiconductor electrode layer used in an electrochemical device such as a dye-sensitized solar cell.
First, in order to facilitate understanding of the present disclosure, a configuration example of a semiconductor electrode layer obtained by the method for manufacturing a semiconductor electrode layer will be described.
(First configuration example of semiconductor electrode layer)
FIG. 1A is a cross-sectional view and a partially enlarged view of the semiconductor electrode layer 1 formed on the support 6. The semiconductor electrode layer 1 includes the first oxide layer 4 between the metal oxide semiconductor fine particles 2 and 3 disposed on the support 6 and between the metal oxide semiconductor fine particles 2 and 3 and the support 6. It is a metal oxide semiconductor porous layer bound by the second oxide layer 5. The semiconductor electrode layer 1 contains metal oxide semiconductor fine particles having at least two shapes, that is, granular metal oxide semiconductor fine particles 2 and needle-shaped metal oxide semiconductor fine particles 3.
The metal oxide semiconductor fine particles 2 and 3 are made of titanium oxide TiO depending on the characteristics of the semiconductor electrode layer 1.2, Zinc oxide ZnO, tungsten oxide WO3Niobium oxide Nb2O5, Strontium titanate SrTiO3, And tin oxide SnO2It is good to consist of at least 1 sort (s) of oxide chosen from the group which consists of.
In many cases, the metal element constituting the first oxide layer 4 is preferably the same metal element as that constituting the metal oxide semiconductor fine particles 2 and 3. In such a case, the adhesion between the metal oxide semiconductor fine particles 2 and 3 and the first oxide layer 4 is expected to be the best. The first oxide layer 4 is mainly bound directly to the metal oxide semiconductor fine particles 2 and 3 and the support 6.
The second oxide layer 5 contains a second oxide having a hardness higher than that of the first oxide forming the first oxide layer 4, and the metal oxide mainly passes through the first oxide layer 4. The solid semiconductor particles 2 and 3 and the support 6 are bound. The second oxide layer 5 reinforces the first oxide layer 4 and strengthens the bond between the metal oxide semiconductor fine particles 2 and 3 and between the metal oxide semiconductor fine particles 2 and 3 and the support 6. To work. The high hardness oxide constituting the second oxide layer 5 is silicon oxide SiO.2Boron oxide B2O3Aluminum oxide Al2O3, And zirconium oxide ZrO2Preferably, the oxide is at least one oxide selected from the group consisting of:
The semiconductor electrode layer 1 includes not only granular metal oxide semiconductor fine particles 2 (hereinafter also referred to as granular fine particles 2) but also acicular metal oxide semiconductor fine particles 3 (hereinafter referred to as acicular fine particles 3) as metal oxide semiconductor fine particles. Also). In such a case, the conductivity is improved as compared with the semiconductor electrode layer 1 that does not contain the acicular fine particles 3. For this reason, when the acicular fine particles 3 are included, the electrons pass through the junction between the fine particles having a large resistance by using the long intra-fine particle conductive path in the longitudinal direction of the acicular fine particles 3. It is conceivable that the semiconductor electrode layer 1 can be moved less frequently.
The average particle diameter of the primary particles of the granular fine particles 2 is not particularly limited, but it is preferably 1 nm or more and 100 nm or less because the visible light transmittance can be increased and the specific surface area can be increased.
On the other hand, the average diameter of the primary particles of the acicular fine particles 3 is preferably 0.1 μm or more and 1 μm or less, and the average length is preferably 1 μm or more and 10 μm or less. When the average length is shorter than 1 μm, the acicular fine particles 3 cannot form an effective conductive path in the semiconductor electrode layer 1, and as a result, the performance of the electrochemical device using the semiconductor electrode layer 1 is improved. Tend to be insufficient. For example, when a dye-sensitized solar cell is configured, the effect of increasing current collection efficiency and improving photoelectric conversion efficiency tends to be insufficient. Moreover, when the average length is longer than 10 μm, the pot life of the paint tends to deteriorate.
The ratio of the blending mass of the needle-shaped fine particles 3 to the blending mass of the granular microparticles 2 (= (the blending mass of the needle-shaped microparticles 3) / (the blending mass of the granular microparticles 2)) is 0.05 to 0.25. It is desirable. If it is less than 0.05, the amount of acicular fine particles 3 is too small, and the effect of improving the conductivity of the semiconductor electrode layer 1 is insufficient. On the other hand, when it exceeds 0.25, the effect of improving the conductivity of the semiconductor electrode layer 1 is great, but the actual surface area of the metal oxide semiconductor porous layer is reduced, and the performance as an electrode is lowered. As a result, for example, when a dye-sensitized solar cell having the semiconductor electrode layer 1 is configured, high photoelectric conversion efficiency cannot be realized.
When preparing a paint containing the acicular fine particles 3, the degree of dispersion of the acicular fine particles 3 is more preferable as the dispersion progresses. Specifically, for example, the dispersion processing time such as bead dispersion may be increased. As the dispersion progresses, a large number of conductive paths are formed uniformly by the acicular fine particles 3 in the semiconductor electrode layer 1 and the actual surface area of the acicular fine particles 3 increases. As a result, the conductivity of the semiconductor electrode layer 1 containing the acicular fine particles 3 is improved, and the performance of an electrochemical device using the same is improved. For example, in an electrochemical device configured as a dye-sensitized solar cell, current collection efficiency is improved and photoelectric conversion efficiency is improved.
It is good also as a structure which provides the close_contact | adherence auxiliary | assistant layer 7 between the support body 6 and the semiconductor electrode layer 1. FIG. FIG. 1B is a cross-sectional view showing an example in which the adhesion auxiliary layer 7 is provided on the support 6 and the semiconductor electrode layer 1 is formed thereon. The adhesion auxiliary layer 7 is a layer provided to improve adhesion when the adhesion between the semiconductor electrode layer 1 and the support 6 is not sufficient. As an example in which the adhesiveness tends to be insufficient, an example in which the support 6 is a base material on which an ITO layer is provided can be given. Examples of the material of the adhesion auxiliary layer 7 include polyacrylate resins, polyamide resins, polyamideimide resins, polyester resins, metal element chlorides (titanium tetrachloride, etc.), peroxides (titanium peroxide, etc.), Hydrolysis / dehydration condensation products such as alkoxides can be used. When the semiconductor electrode layer 1 is used as a semiconductor electrode layer of a dye-sensitized solar cell, it is desirable that the adhesion auxiliary layer 7 has a thickness that does not significantly reduce the photoelectric conversion efficiency of the dye-sensitized solar cell.
The support 6 is not particularly limited as long as it is stable in the environment in which it is used. The material of the support 6 may be an inorganic material or an organic material. Further, the shape of the support 6 is not particularly limited, and is, for example, a film shape, a sheet shape, a plate shape, or the like. Moreover, it is preferable that the material of the support 6 is a material that has a high blocking performance to block moisture and gas from entering the electrochemical device from the outside, and is excellent in solvent resistance and weather resistance. The thickness of the support 6 is not particularly limited, and can be appropriately selected in consideration of light transmittance, blocking performance for blocking water vapor transmission, mechanical strength, and the like.
When the semiconductor electrode layer 1 is used as a semiconductor electrode layer of a dye-sensitized solar cell, when the support 6 is required to be light transmissive, a material that easily transmits light as the support 6. And shape. For example, transparent inorganic substrates such as quartz, sapphire, and glass, and triacetyl cellulose (TAC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyester (TPEE), polyimide (PI), polyamide (PA) , Aramid, polyethylene (PE), polyacrylate, polyethersulfone, polysulfone, polypropylene (PP), diacetylcellulose, polyvinyl chloride, acrylic resin (PMMA), polycarbonate (PC), epoxy resin, urea resin, urethane resin, melamine Examples thereof include a transparent plastic substrate made of a polymer and a polymer material such as a cycloolefin polymer resin (COP). Among these, it is preferable to use a substrate material having a particularly high visible light transmittance. The thickness of the plastic substrate is not particularly limited, but is preferably 38 μm or more and 500 μm or less from the viewpoint of productivity.
Further, as the support 6, a light transmissive substrate with a transparent conductive layer in which a transparent conductive layer is formed on a light transmissive substrate may be used. Known materials can be used for the transparent conductive layer. Specifically, ITO (indium tin oxide), FTO (fluorine-doped tin oxide), antimony-doped tin oxide (ATO), tin oxide ( SnO2), Zinc oxide, indium / zinc composite oxide (IZO), and the like, but are not limited thereto. The transparent conductive layer may be a single layer film or a laminated film of these materials, and two or more kinds of materials may be used in combination. In addition, regarding ITO, when it processes in air | atmosphere at about 250 degreeC or more, the deterioration by oxidation will arise. Oxygen vacancies are filled by oxidation, thereby reducing the number of carriers and decreasing the conductivity. Therefore, when ITO is used, when heat treatment is performed at a high temperature, it is preferable to perform the heat treatment in an oxygen-free atmosphere.
(Second configuration example of semiconductor electrode layer)
A second configuration example of the semiconductor electrode layer will be described. FIG. 2 is a cross-sectional view and a partially enlarged view of the semiconductor electrode layer 21 formed on the support 6. The semiconductor electrode layer 21 includes the first oxide layer 4 between the metal oxide semiconductor fine particles 2 and 3 disposed on the support 6 and between the metal oxide semiconductor fine particles 2 and 3 and the support 6. It is a metal oxide semiconductor porous layer bound by the second oxide layer 5. The second configuration example of the semiconductor electrode layer is different from the first configuration example in that the granular metal oxide semiconductor fine particles 2 forming the semiconductor electrode layer 21 have a primary particle average particle size of 100 nm or less. One granular fine particle 2A and the second granular fine particle 2B having an average primary particle size larger than 100 nm and 10000 nm or less are composed of two types of fine particles having different sizes. Other than this, the configuration is the same as that of the first configuration example of the semiconductor electrode layer.
Among the granular metal oxide semiconductor fine particles 2, the first granular fine particles 2 </ b> A have an average primary particle diameter of 1 nm or more and 100 nm or less, so that the visible light transmittance can be increased and the specific surface area can be increased. . On the other hand, the primary particle average particle diameter of the second granular fine particles 2B is larger than 100 nm and not larger than 10,000 nm. The larger the average particle diameter of the second granular fine particles 2B, the more the ratio of the blending mass of the second granular fine particles 2B to the blending mass of the first granular fine particles 2A (= (the blending mass of the second granular fine particles 2B). ) / (Mixed mass of the first particulate fine particles 2A)) is larger, the cracks generated in the semiconductor electrode layer (metal oxide semiconductor porous layer) 21 are reduced.
The reason for this is not completely understood, but when relatively large second granular fine particles 2B coexist, the connection between the second granular fine particles 2B and the surrounding first granular fine particles 2A is as follows. Since the number of particles that need to be connected to form the conductive path of the same length is relatively small, it is surely formed on the surface of the granular fine particles 2B. It is conceivable that the number of connecting portions between the first granular fine particles 2A that tends to have insufficient strength is remarkably reduced. Therefore, FIG. 2 shows an example including two types of granular fine particles having different average particle sizes of primary particles, but it is obvious that a configuration including three or more types of granular fine particles having different average particle sizes may be used. is there.
Further, when the second granular fine particles 2B coexist, incident light is easily scattered, the internal HAZE (haze) of the semiconductor electrode layer 21 is increased, and the total light transmittance is decreased. In the dye-sensitized solar cell using the semiconductor electrode layer 21, the light utilization rate is increased by scattering of incident light, and the photoelectric conversion performance is improved.
The average primary particle diameter of the second granular fine particles 2B is more preferably 200 nm or more and 5000 nm or less. When the average particle diameter of the primary particles is smaller than 200 nm, the effect of suppressing the occurrence of cracks in the semiconductor electrode layer 21 is insufficient, and the performance of scattering incident light tends to be insufficient. On the other hand, when the average particle diameter of the primary particles is larger than 5000 nm, the second granular fine particles 2B tend to precipitate in the coating liquid, and the pot life of the coating liquid tends to decrease.
Further, the ratio of the blending mass of the second granular fine particles 2B to the blending mass of the first granular fine particles 2A is preferably 0.06 or more and 6 or less. When it is less than 0.06, the effect of suppressing the occurrence of cracks in the semiconductor electrode layer 21 becomes insufficient, and the performance of scattering incident light tends to be insufficient. On the other hand, when it is larger than 6, the effect of suppressing the occurrence of cracks in the semiconductor electrode layer 21 is sufficient and the performance of scattering incident light is sufficient, but the actual surface area of the metal oxide semiconductor particles in the semiconductor electrode layer 21 is sufficient. This may decrease the performance of an electrochemical device using the semiconductor electrode layer 21, for example, a dye-sensitized solar cell.
The larger the ratio of the blending mass of the needle-shaped fine particles 3 to the blending mass of the granular microparticles 2 (= (the blending mass of the needle-shaped microparticles 3) / (the blending mass of the granular microparticles 2)), the more the second granular microparticles 2B. The larger the ratio (= (the blending mass of the second particulate microparticles 2B) / (the blending mass of the first particulate microparticles 2A)) to the blending mass of the first particulate microparticles 2A is, the larger the semiconductor electrode layer 1 is. A light scattering function is imparted to the semiconductor electrode layer 21 so that the internal HAZE of the semiconductor electrode layer 21 increases and the total light transmittance decreases. Further, by adsorbing the photosensitizing dye to the semiconductor electrode layer 21, the total light transmittance is further lowered. The blending mass of the granular fine particles 2A and 2B and the acicular fine particles 3 is selected within the above-described range so that the internal HAZE value is 85% or more and the total light transmittance is 50% or less. Good. By doing in this way, in the dye-sensitized solar cell using the semiconductor electrode layer 21, the light utilization rate is improved and the photoelectric conversion performance is improved.
When the acicular fine particles 3 are contained in the semiconductor electrode layer (metal oxide semiconductor porous layer) 21, the photoelectric conversion efficiency is improved while maintaining the hardness of the semiconductor electrode layer 21 and the adhesion to the substrate. Can do. In addition, no cracks are generated in the semiconductor electrode layer 21 in the solvent evaporation step and / or the baking step after application or printing of the coating liquid due to the inclusion of the acicular fine particles 3. However, the acicular fine particles 3 do not have an effect of suppressing the occurrence of cracks or are not sufficient. Therefore, the internal HAZE and the total light transmittance can be made within the above ranges by including the needle-shaped fine particles 3 in the semiconductor electrode layer 21, but if the semiconductor electrode layer 21 does not contain the granular fine particles 2B, the semiconductor electrode In some cases, the occurrence of cracks in the layer 21 cannot be suppressed.
(Method for manufacturing semiconductor electrode layer)
A method for manufacturing a semiconductor electrode layer according to the first embodiment of the present disclosure will be described. For example, a method for manufacturing the semiconductor electrode layer 1 or 21 described above will be described. By using the manufacturing method of the semiconductor electrode layer according to the first embodiment of the present disclosure, the performance of the adhesion of the semiconductor electrode layer to the support 6 is excellent, and the support 6 includes a resin film substrate. In addition, the semiconductor electrode layer can be sintered at a high temperature. And when it uses for a dye-sensitized solar cell, the semiconductor electrode layer 1 or 21 excellent in the photoelectric conversion efficiency can be formed.
<Preparation of coating liquid>
For example, in order to produce the semiconductor electrode layer 1 shown in FIG. 1, first, the metal oxide semiconductor fine particles 2 and 3 are each dispersed in an appropriate organic solvent to prepare two paste-like dispersions. As the dispersion method, known methods such as stirring treatment, ultrasonic dispersion treatment, bead dispersion treatment, kneading treatment, and homogenizer treatment can be preferably used.
As the solvent, a solvent that can disperse the metal oxide semiconductor fine particles 2 and 3 and can dissolve the first compound and the second compound is appropriately selected and used. Specifically, for example, it is selected from alcohols, ketones, hydrocarbons, amides, sulfides and the like.
The compounding quantity of the metal oxide semiconductor fine particles 2 and 3 is 1 mass% or more and 50 mass% or less of the mass of the coating liquid formed by adding the 1st compound and 2nd compound which are mentioned later, for example, 20 mass %. When the amount is less than 1% by mass, there is a disadvantage that a metal oxide semiconductor fine particle layer having a sufficient thickness cannot be formed by a coating method. On the other hand, when it is larger than 50% by mass, the viscosity of the coating solution becomes too high, and there is a disadvantage that handling becomes difficult when forming the metal oxide semiconductor fine particle layer by a coating method or the like.
Next, the above-mentioned two dispersions are mixed at a predetermined ratio, and the first compound and the second compound are added to this, and stirred to dissolve to obtain a uniform coating solution. A solvent may be further added to adjust the concentration. Either order may be sufficient as the order which adds a 1st compound and a 2nd compound. A 1st compound is a compound which hydrolyzes and produces | generates a 1st oxide. The second compound is a compound that is harder to hydrolyze than the first compound and that produces a second oxide having a higher hardness than the first oxide when hydrolyzed.
Specifically, a metal element salt or alkoxide may be used as the first compound. For example, the metal element may be at least one element selected from the group consisting of titanium Ti, aluminum Al, silicon Si, vanadium V, zirconium Zr, niobium Nb, and tantalum Ta. In addition, unpurified metal oxide semiconductor fine particles and organic solvents usually contain more or less adsorbed or occluded water, but as a first compound, they react with these water at room temperature, and partly Alternatively, it is preferable to use a compound that is fully hydrolyzed in the coating solution. In this case, it is observed that the viscosity increases during the preparation of the coating liquid. This is because, as the mixing of the first compound, the metal oxide semiconductor fine particles, and the organic solvent proceeds, the first compound reacts with moisture, and the first oxide generated by hydrolysis of the first compound is a metal. This is considered to be due to bonding to the surfaces of the oxide semiconductor fine particles 2 and 3 to connect the metal oxide semiconductor fine particles 2 and 3 together.
On the other hand, as the second compound, an alkoxide of at least one element selected from the group consisting of silicon Si, boron B, aluminum Al, and zirconium Zr is preferably used.
The blending amount of the first compound is, for example, 0.01% by mass or more and 20% by mass or less of the mass of the coating liquid. Moreover, the compounding quantity of a 2nd compound shall be 0.01 to 20 mass% of the mass of a coating liquid, for example. In order to obtain the desired hardness and adhesion to the support of the semiconductor electrode layer 1, the compounding amounts of the first compound and the second compound are the materials and dispersibility of the metal oxide semiconductor fine particles 2 and 3, Depending on the material type of the first compound and the second compound, it is appropriately selected within the above range. When the blending amounts of the first compound and the second compound are outside the above ranges, it tends to be difficult to achieve both the hardness of the semiconductor electrode layer 1 and the adhesion to the support 6. Further, when the semiconductor electrode layer 1 is used as a semiconductor electrode layer of a dye-sensitized solar cell, depending on the material type of the first compound and the second compound, the adsorption of the photosensitizing dye is inhibited, and the photoelectric Conversion efficiency may decrease.
When the semiconductor electrode layer 21 shown in FIG. 2 is produced, first, the first granular fine particles 2A, the second granular fine particles 2B, and the acicular fine particles 3 constituting the metal oxide semiconductor fine particles 2 and 3, respectively, Then, three paste dispersions are prepared by dispersing in an appropriate organic solvent. Next, the above three dispersions are mixed at a predetermined ratio, and the first compound and the second compound are added to this, and dissolved by stirring to obtain a uniform coating solution.
<Formation of semiconductor electrode layer>
Next, the layer of the coating liquid is deposited on the support 6 by a known method such as a coating method or a printing method. Examples of the coating method include a micro gravure coating method, a wire bar coating method, a direct gravure coating method, a die coating method, a dip method, a spray coating method, a reverse roll coating method, a curtain coating method, a comma coating method, a knife coating method, and a spin coating method. A coating method or the like can be used. Further, as the printing method, for example, a relief printing method, an offset printing method, a gravure printing method, an intaglio printing method, a rubber plate printing method, a screen printing method, and the like can be used.
Next, the solvent is removed by evaporation from the layer of the coating liquid to form a metal oxide semiconductor fine particle layer containing the first compound, the second compound, and the first oxide. As a method for evaporating the solvent, the solvent may be evaporated at room temperature or may be evaporated by heating. However, in order to suppress uneven evaporation, it is preferable to adjust the evaporation rate of the solvent. Specifically, it is preferable to evaporate in a temperature range of 20 ° C. or more and 100 ° C. or less and a time range of 30 seconds to 20 minutes. When the solvent is removed by evaporation, the first oxide contained in the coating liquid is bound to the metal oxide semiconductor fine particles 2 and 3. The first compound reacts with moisture in the air and is hydrolyzed. As a result, most of the first compound is converted to the first oxide before entering the next baking step. Then, a metal oxide semiconductor porous layer in which the metal oxide semiconductor fine particles 2 and 3 and between the metal oxide semiconductor fine particles 2 and 3 and the support 6 are bound by the first oxide layer 4 is formed. Is done. At this time, in order to promote the hydrolysis of the first compound, the temperature during and / or after the evaporation step may be maintained at 25 ° C. or more and 200 ° C. or less, for example, about 80 ° C. Moreover, it is also possible to perform an evaporation process and the following baking process simultaneously.
<Baking treatment>
Next, the metal oxide semiconductor porous layer is fired to improve the electronic connection between the metal oxide semiconductor fine particles 2 and 3, and the mechanical strength of the metal oxide semiconductor porous layer and the support 6 is improved. There is no particular limitation on the firing temperature, but if the temperature is too high, the support 6 may be deteriorated by heat, so the firing temperature is 40 ° C. or higher and 1000 ° C. or lower, and usually 300 ° C. or higher and 600 ° C. or lower. It is preferable. When a plastic material is used as the material of the support 6, it is preferably not higher than the heat-resistant temperature (for example, not higher than the glass transition point), and usually not lower than 40 ° C. and not higher than 200 ° C. Moreover, although there is no restriction | limiting in particular in baking time, Usually, it is about 30 seconds or more and 10 hours or less.
This firing process forms a metal oxide semiconductor porous layer in which fine particles are fused in the vicinity of the contacts, and the fine particles are connected in a network via fine connections, leaving voids between the fine particles as vacancies. Is done. (Hereinafter, the phenomenon in which the fine particles are connected through fine connecting portions by fusion in the vicinity of the contact is referred to as necking, and the process for forming such a connection is sometimes referred to as necking process.) The semiconductor porous layer can be used as a semiconductor electrode layer of a dye-sensitized solar cell when a photosensitizing dye is adsorbed.
At this time, the ratio of the second compound that is hydrolyzed until the firing step is small, and most of the second compound is preferably hydrolyzed by moisture supplied from the air in the firing step. In this case, the second oxide generated by hydrolysis of the second compound is mainly bound on the first oxide layer 4 to form the second oxide layer 5, and the metal oxide The first oxide layer 4 bonded between the semiconductor fine particles 2 and 3 and between the metal oxide semiconductor fine particles 2 and 3 and the support 6 is strongly reinforced. As a result, a semiconductor electrode layer (metal oxide semiconductor porous layer) 1 or 23 having excellent mechanical strength and high adhesion to the support 6 is obtained.
Although only the first compound may be used, the adhesion between the semiconductor electrode layer (metal oxide semiconductor porous layer) 1 or 23 and the support 6 may be insufficient only with the first compound. This is because a considerable portion of the first compound that is prone to hydrolysis is hydrolyzed before the coating liquid is applied to the support 6. The first oxide generated before the coating liquid is applied to the support 6 connects the metal oxide semiconductor fine particles 2 and 3 to increase the mechanical strength of the metal oxide semiconductor porous layer. This is because it contributes but does not contribute to improving the adhesion to the support 6. On the other hand, most of the hydrolysis of the second compound occurs after the coating liquid is applied to the support 6, so that the second oxide improves the mechanical strength of the metal oxide semiconductor porous layer. Moreover, it contributes to the improvement of the adhesiveness with the support body 6 as well. Only the second compound may be used, but the second compound alone tends to cause surface layer peeling or damage. This is because the second compound is less reactive with the surface of the metal oxide semiconductor fine particles 2 and 3 than the first compound, so that the number of necking between the fine particles 2 and 3 is reduced only with the second compound. This is because the strength tends to be insufficient. That is, in order to achieve both the mechanical strength of the semiconductor electrode layer 1 or 23 and the adhesion to the support 6, it is preferable to use both the first compound and the second compound.
<Electromagnetic wave treatment>
After the firing treatment, the metal oxide semiconductor porous layer is heated by electromagnetic wave irradiation in order to promote necking. When a material having a low softening point such as a plastic material is used as the material of the support 6, the metal oxide semiconductor porous layer is heated by irradiating electromagnetic waves, and the support 6 is cooled. In addition, the baking process mentioned above may be abbreviate | omitted and a necking process may be performed by an electromagnetic wave process instead of a baking process. The method of manufacturing a semiconductor electrode layer according to the first embodiment of the present disclosure includes a process-saving process for manufacturing a film-type dye-sensitized solar cell, a reduction in the firing temperature of the metal oxide semiconductor porous layer on the glass substrate, Contributes to shortening process time and improving photoelectric conversion efficiency of film-type dye-sensitized solar cells. In Patent Document 2 exemplified in the background art section, the semiconductor fine particle film is sintered with a microwave of 28 GHz, so that energy is selectively given to the semiconductor fine particles using dielectric loss to perform the sintering. The temperature at which the film can be altered or deformed, although there is no heat transfer loss from the base material compared to the normal electric furnace and other electromagnetic wave sintering. There is no report that heating can be performed in the region, and there is no report that conversion efficiency is improved when a dye-sensitized photoelectric conversion element is used as compared with low-temperature sintering at 150 ° C. Moreover, since the microwave irradiation apparatus is large-sized and is intended for a batch type, it is not suitable for a roll-to-roll process or the like.
Examples of electromagnetic waves include infrared rays, ultraviolet rays, and visible rays. Other irradiation type treatments include microwave treatment, flame treatment, plasma treatment in air, plasma treatment in vacuum, corona treatment, induction heating treatment and the like, and these methods may be used.
When the support 6 uses a material having a low softening point such as a plastic material such as a resin film base, for example, a plastic film base, it is preferable to perform electromagnetic wave irradiation while cooling the support 6. In order to promote the bonding between the fillers of the metal oxide semiconductor porous layer by electromagnetic wave irradiation, the metal oxide semiconductor is heated to a temperature at which the resin film substrate is altered and deformed (for example, the heat resistance temperature of the resin film substrate or higher). This is because the resin film substrate tends to be deformed and deteriorated by heating because it is necessary to perform the treatment on the porous layer. The specific heating temperature range is typically 40 ° C. or higher and 1000 ° C. or lower, and preferably 200 ° C. or higher and 550 ° C. or lower. The treatment time is not particularly limited, but is usually 1 second or more and 10 hours or less. The specific cooling temperature range is typically 150 ° C. or lower, preferably 0 ° C. or lower. In heating by electromagnetic wave irradiation, it is possible to heat to a high temperature instantly, so that the processing time can be shortened as compared with heating by a baking furnace or oven.
The support 6 is cooled by cooling a cooling plate such as a copper plate or a cooling member such as a cooling roll on the surface of the support 6 on which the metal oxide semiconductor porous layer is not formed (for example, the back surface of the electromagnetic wave irradiation site). You may carry out by making it closely_contact | adhere. For example, when a cooling plate is used, the support 6 on which the metal oxide semiconductor porous layer is formed is placed on the cooling plate. At this time, the surface of the support 6 on which the metal oxide semiconductor porous layer is not formed is a surface that is in close contact with the cooling plate. And while irradiating electromagnetic waves with respect to a metal oxide semiconductor porous layer, the support body 6 is cooled from the surface side by which a metal oxide semiconductor porous layer of the support body 6 is not formed with a cooling plate. For example, when a cooling roll is used, the surface of the cooling roll is brought into close contact with one main surface of the support on which the metal oxide semiconductor porous layer is not formed, whereby the support 6 is cooled. Is called.
For example, a coolant such as water is circulated inside a cooling member such as a cooling plate or a cooling roll, so that the cooling temperature can be reduced to an appropriate cooling temperature (for example, below the temperature at which the resin film substrate is altered or deformed by heat). The temperature of the cooling member is adjusted to (coolable temperature). When the support 6 on which the metal oxide semiconductor porous layer is formed is brought into contact with the cooling member, it is preferable that the gap between the cooling member and the support 6 is small. It is possible to prevent the resin film base material from being altered and deformed by bringing the cooling member and the support 6 into contact with each other without any gaps and sufficiently dissipating heat. Between the support 6 and the cooling member, an antifreeze liquid such as a liquid having a low freezing point such as ethanol or methanol, a cooling medium layer such as a gel-like coolant or an antifreeze sheet is provided to cool the support 6 and the cooling member. The support 6 may be cooled in a state where there is no gap between the members. In addition, a cooling member is not limited to a cooling plate and a cooling roll, What is necessary is just to have a cooling function which cools the support body 6 to appropriate temperature.
When using a resin film with a transparent conductive layer in which a transparent conductive layer is formed on one main surface of a resin film substrate as the support 6 and using ITO as the material of the transparent conductive layer, the atmosphere in which electromagnetic waves are irradiated is oxygen It is preferable that the atmosphere does not contain. This is because when ITO is treated at a high temperature (for example, about 250 ° C. or higher) in an atmosphere containing oxygen such as the air, oxygen deficiency disappears and carriers are reduced by taking in oxygen, resulting in an increase in resistance. This is because there is a problem.
For example, examples of the atmosphere not containing oxygen include, but are not limited to, an inert gas atmosphere such as nitrogen, argon, and helium, a vacuum, a hydrogen atmosphere, and the like. As for FTO, since the oxygen deficient portion is doped with fluorine, even if heat treatment is performed at a high temperature in the atmosphere, there is little influence on the conductivity.
For the purpose of increasing the actual surface area of the metal oxide semiconductor porous layer after electromagnetic wave irradiation or increasing the necking between the metal oxide semiconductor fine particles 2 and 3, metal salts such as titanium tetrachloride and titanium alkoxide, and metal alkoxides Necking processing may be performed using. Further, organic substances and unreacted substances remaining in the metal oxide semiconductor porous layer may be removed by washing with a solvent or the like.
When a plastic material is used as the material of the support 6, the semiconductor electrode layer 1 may be pressure-bonded to the support 6 by a heat and pressure process, for example, a calendar process.
When the support 6 is a substrate that can withstand high-temperature firing such as glass or metal (metal mesh, metal sheet, metal film, etc.), the substrate does not have to be cooled when the electromagnetic wave is irradiated. In this case, an electromagnetic wave irradiation process may be performed instead of the baking process. By performing the baking treatment by electromagnetic wave irradiation instead, the process can be saved with respect to drying and baking.
However, even in this case, when the support 6 has a conductive layer, it is necessary to change the atmosphere according to the material of the conductive layer. That is, when the support 6 has a transparent conductive layer, if the transparent conductive layer cannot be baked in an oxygen atmosphere such as ITO, the atmosphere for electromagnetic wave irradiation needs to be an atmosphere that does not contain oxygen. . For example, examples of the atmosphere not containing oxygen include, but are not limited to, an inert gas atmosphere such as nitrogen, argon, and helium, a vacuum, a hydrogen atmosphere, and the like.
<Pressure treatment of metal oxide semiconductor porous layer>
In addition to the electromagnetic wave irradiation treatment, a treatment for enhancing the physical contact between the fillers of the semiconductor fine particle layer (metal oxide semiconductor porous layer) such as a calendar treatment and a press treatment may be performed. Thereby, for example, the energy conversion efficiency of the dye-sensitized solar cell can be improved. The pressure treatment of the semiconductor fine particle layer may be performed before or after irradiation heating by electromagnetic wave irradiation treatment, or before and after.
¡Calendar treatment or press treatment promotes contact between the semiconductor fine particles, increases the transparency of the semiconductor fine particle layer, and reduces the thickness of the semiconductor fine particle layer. As a result, for example, in a dye-sensitized solar cell using a resin film substrate or a glass substrate, the conversion efficiency is improved. In the case of calendar treatment, it is preferable that the temperature of the press roll is less than 150 ° C., the temperature of the back roll is less than 150 ° C., and the linear pressure is more than 0 ° C. and 500 kg / cm or less. When the temperature is higher than the above temperature, the semiconductor fine particle film tends to be deformed due to heat loss or the like. In the case of a press, the load is 15 t / 25 mm within the range below the temperature that the glass can withstand.2The following is preferred. When the load is higher than this, the semiconductor fine particles become too dense, voids as a porous structure disappear, and it becomes difficult to adsorb the dye and soak in the electrolytic solution, so that the performance tends to deteriorate. The pressurizing process such as the calendar process or the press process may be performed twice or more.
The semiconductor electrode layer and the method for manufacturing the semiconductor electrode layer will be described in more detail. When the semiconductor electrode layer 1 or 23 described above is used for a dye-sensitized solar cell, the following is performed.
The thickness of the semiconductor electrode layer 1 or 23 is preferably 1 μm or more and 30 μm or less. When the thickness is less than 1 μm, sufficient photoelectric conversion efficiency cannot be obtained. As the thickness is increased, the photoelectric conversion efficiency is improved. However, when the thickness exceeds 30 μm, the effect of improving the photoelectric conversion efficiency due to the increase in the film thickness becomes poor. Therefore, the thickness is preferably 30 μm or less.
As the material of the metal oxide semiconductor fine particles 2 and 3, various metal oxide semiconductors, compounds having a perovskite structure, and the like can be used. At this time, the material of the metal oxide semiconductor fine particles 2 and 3 is preferably an n-type semiconductor material in which conduction band electrons become carriers under photoexcitation to generate an anode current. Such a semiconductor material is specifically exemplified by TiO.2, ZnO, WO3, Nb2O5, SrTiO3, And SnO2Among these, TiO2Is particularly preferred. However, the material of the metal oxide semiconductor fine particles 2 and 3 is not limited to these. Also, two or more of these materials can be mixed and used.
In order to transmit visible light and increase the specific surface area, the average particle diameter of the primary particles is preferably 1 to 100 nm in the granular metal oxide semiconductor fine particles 2 (in this case, however, the metal Cracks occur in the oxide semiconductor porous layer, the conductivity between the metal oxide semiconductor fine particles decreases, and the photoelectric conversion performance of the dye-sensitized solar cell using the metal oxide semiconductor porous layer decreases. (For such a case, see Embodiment 2 described later.) As the metal oxide semiconductor fine particles 2 and 3, commercially available products may be used, or a predetermined value may be obtained by subjecting chloride or alkoxide to hydrolysis treatment or hydrothermal treatment by a known method such as a sol-gel method. You may produce the thing of a particle size.
When titanium oxide is used as the material of the metal oxide semiconductor fine particles 2 and 3, the crystal type thereof may be one type selected from a rutile type, anatase type, and brookite type, or a mixture of two or more types. Examples of commercially available products include granular metal oxide semiconductor fine particles 2 having an average primary particle diameter of 1 to 100 nm, such as P25 and P90 (trade names) manufactured by Degussa, manufactured by Ishihara Sangyo Co., Ltd. ST-01 and ST-21 (above, trade names), Super Titania F-1, F-2, F-3, F-4, F-5, and F-6 (above, manufactured by Showa Denko KK) Trade name), SSP-25, SSP-20, SSP-M, and STR series (above, trade names) manufactured by Sakai Chemical Industry Co., Ltd., MT-150A, MT-500B, MT- manufactured by Teika Co., Ltd. Use 600B, MT-700B, AMT-100, AMT-600, TKP-101, TKP-102 (above, trade name), NanoTek Powder series (trade name) manufactured by CI Kasei Co., Ltd. Can do.
Further, as the needle-shaped metal oxide semiconductor fine particles 3, FTL-100, FTL-110, FTL-200, FTL-300, FT-1000, FT-2000, FT-3000, FS- manufactured by Ishihara Sangyo Co., Ltd. 10P and FS-10D (above, trade names) can be used.
When zinc oxide is used as the material of the metal oxide semiconductor fine particles 2 and 3, as a commercial product, as the granular metal oxide semiconductor fine particles 2, for example, MZ-300 and MZ-500 (manufactured by Teika Co., Ltd.) Product name), FZO-50 (product name) manufactured by Ishihara Sangyo Co., Ltd., NanoTek Powder series (product name) manufactured by CI Kasei Co., Ltd., FINEX series (product name) manufactured by Sakai Chemical Industry Co., Ltd. F-1, F-2, F-3, Pazet CK, Pazet GK-40 (above, trade name) manufactured by Co., Ltd. can be used. Further, as the needle-shaped metal oxide semiconductor fine particles 3, Panatetra (trade name) manufactured by Amtec Co., Ltd. can be used.
When tin oxide is used as the material for the metal oxide semiconductor fine particles 2 and 3, commercially available products include, for example, granular metal oxide semiconductor fine particles 2 having an average particle diameter of 15 nm manufactured by Johnson Matthey Co., Ltd. A NanoTek Powder series (trade name) manufactured by Kasei Co., Ltd. can be used.
In the second configuration example of the semiconductor electrode layer, when a commercially available product is used as the granular metal oxide semiconductor fine particles 2A, a commercially available product in which the above-described primary particles have an average particle diameter of 1 nm to 100 nm can be used. When a commercially available product is used as the granular metal oxide semiconductor fine particles 2B, for example, PT-301, CR-EL, ET-500W, ET-600W, and ST- manufactured by Ishihara Sangyo Co., Ltd. can be used if they are titanium oxide fine particles. 41 (above, trade name), G-1, G-2, and F-10 (above, trade name) manufactured by Showa Denko KK, JR (trade name) manufactured by Teika Corporation, Fuji Titanium Industry Co., Ltd. ) TA-100, TA-200, TA-300, TA-500 (above, trade name), etc. can be used. Moreover, if it is a zinc oxide microparticles | fine-particles, Sakai Chemical Industry Co., Ltd. LPZINC-2, LPZINC-5 (above, brand name) etc. can be used. Alternatively, a product having a predetermined particle diameter may be produced by subjecting chloride, alkoxide, or the like to a hydrolytic treatment or hydrothermal treatment by a known method such as a sol-gel method.
It should be noted that the materials of the metal oxide semiconductor fine particles 2 and 3 described above can be appropriately mixed and used.
As the first compound, a salt or alkoxide that can be dissolved in an organic solvent can be used. The first compound may be a compound of at least one element such as Ti, Al, Si, V, Zr, Nb, and Ta. In many cases, the element is the same element as the metal element constituting the metal oxide semiconductor fine particle 2, and the first oxide generated from the first compound and the metal oxide semiconductor fine particle 2 are formed. The constituent metal oxide is preferably the same kind of oxide. It can be expected that the adhesion between the metal oxide semiconductor fine particles 2 and the first oxide layer 4 will be the best.
Further, as the first compound, it is preferable to use the first compound hydrolyzed at room temperature by the water usually contained in the metal oxide semiconductor fine particles 2 and / or the organic solvent. In this case, as described above, the hydrolysis of the first compound starts in the coating liquid, and the metal oxide semiconductor fine particles 2 are connected by the generated first oxide. A network is easily formed.
As the salt, it is possible to use nitrates, sulfates, acetates, oxalates, halides, etc. that are soluble in a solvent. Specifically, TiOSO4, Zr (CH3COO)2O, Zr (CH3COO)4, Al (NO3)3, Al (CH3COO)3, Al2(SO4)3TiCl4AlCl3, Ti (C2O4)2, Zr (C2O4)2And Al2(C2O4)3Etc. can be used.
Further, the alkoxide that can be used can be represented by the following general formula.
General formula of alkoxide:
Figure JPOXMLDOC01-appb-C000001
 In the above general formula, the metal alkoxide may be any of a monomer (m = 0), an oligomer (m = 1 to 10), and a polymer (m> 10), and two or more kinds may be mixed and used. Examples of the alkoxy group include a methoxy group (n = 1), an ethoxy group (n = 2), an n-propoxy group, an i-propoxy group (n = 3), an n-butoxy group, an i-butoxy group, sec- A butoxy group, a tert-butoxy group (above, n = 4), a 2-ethylhexoxy group, and other alkoxy groups derived from lower and higher alcohols can be used. Moreover, the alkoxide may be modified with β-diketones such as acetylacetone. A part of the alkoxy group may be substituted with a hydroxy group.
As the commercial product, for example, the following can be used. That is, Nippon Soda Co., Ltd. A-1, B-1, TOT, TOG, T-50, T-60, A-10, B-2, B-4, B-7, B-10, TBSTA, DPSTA-25, S-151, S-152, S-181, TAT, and TLA-A-50 (above, trade names), TPT, TBT, DBT, TST, TEAT, TAA, manufactured by Mitsubishi Gas Chemical Co., Ltd. TEAA, TLA, and OGT (trade name), KR TTS, KR 46B, KR 55, KR 41B, KR 38S, KR 138S, KR 238S, 338X, KR 44, KR 9SA, KR manufactured by Ajinomoto Fine Techno Co., Ltd. ET and AL-M (above, trade names), TA-10, TA-25, TA-22, TA-30, TC-1 manufactured by Matsumoto Fine Chemical Co., Ltd. 0, TC-401, TC-200, TC-750, TC-400, TC-300, TC-310, TC-315, TPHS, ZA-40, ZA-65, ZC-150, ZC-540, ZC- 570, ZC-580, ZC-700, ZB-320, and ZB-126 (above, trade names), Colcoat Co., Ltd. ethyl silicate 28, ethyl silicate 28P, N-propyl silicate, N-butyl silicate, MCS- 18, methyl silicate 51, methyl silicate 53A, ethyl silicate 40, ethyl silicate 48, EMS-485, SS-101, HAS-6, HAS-1, HAS-10, SS-C1, Colcoat P, Colcoat N-103X, And magnesium ethylate (above, trade name) can be used.
When titanium oxide is used as the material of the metal oxide semiconductor fine particles 2 and 3, the first compound is, for example, titanium tetrachloride TiCl.4, Titania sulfate TiOSO4, Tetramethoxy titanium Ti (OCH3)4Tetrapropoxytitanium Ti (OCH2CH2CH3)4, Tetrabutoxy titanium Ti (OCH2CH2CH2CH3)4, Tetrapentoxytitanium Ti (OCH2CH2CH2CH2CH3)4, Butoxy titanium dimer, butoxy titanium oligomer, butoxy titanium polymer, tetramethoxy zirconium Zr (OCH3)4, Tetraethoxyzirconium Zr (OCH2CH3)4Tetrapropoxyzirconium Zr (OCH2CH2CH3)4Tetrabutoxyzirconium Zr (OCH2CH2CH2CH3)4, Trimethoxyaluminum Al (OCH3)3, Triethoxyaluminum Al (OCH2CH3)3, Tripropoxyaluminum Al (OCH2CH2CH3)3, Tributoxyaluminum Al (OCH2CH2CH2CH2CH3)3Etc. can be preferably used.
On the other hand, as the second compound, an alkoxide such as Si, B, Al, and Zr is used, and the oxide forming the second oxide layer 5 is SiO.2, B2O3, Al2O3And ZrO2It is preferable that the oxide has high hardness.
When titanium oxide is used as the material of the metal oxide semiconductor fine particles 2 and 3, as the second compound, for example, dimethyldimethoxysilane Si (CH3)2(OCH3)2, Dimethyldiethoxysilane Si (CH3)2(OCH2CH3)2, Methyltrimethoxysilane Si (CH3) (OCH3)3, Methyltriethoxysilane Si (CH3) (OCH2CH3)3, Tetramethoxysilane Si (OCH3)4, Tetraethoxysilane Si (OCH2CH3)4Tetrapropoxysilane Si (OCH2CH2CH3)4Tetrabutoxysilane Si (OCH2CH2CH2CH3)4, Ethoxysilane dimer, ethoxysilane oligomer, ethoxysilane polymer, trimethoxyborane B (OCH3)3, Triethoxyborane B (OCH2CH3)3, Triisopropoxyborane B (OCH (CH3) CH3)3Etc. can be preferably used.
As the solvent, a solvent capable of dissolving the first compound and the second compound and dispersing the metal oxide semiconductor fine particles 2 and 3 is used. For example, methanol, ethanol, 1-propanol, 2-propanol (isopropyl alcohol), 1-butanol, 2-butanol (isobutyl alcohol), 3-methyl-2-propanol (sec-butyl alcohol), and 2-methyl-2 -Selected from alcohols such as propanol (tert-butyl alcohol), ketones such as cyclohexanone and cyclopentanone, hydrocarbon solvents such as hexane, amides such as dimethylformamide (DMF), sulfoxides such as dimethyl sulfoxide (DMSO), etc. At least one or more types can be used.
In order to suppress uneven drying on the surface of the coating liquid layer, a high boiling point solvent can be added to control the evaporation rate of the solvent. Examples of such high-boiling solvents include butyl cellosolve, diacetone alcohol, butyl triglycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, diethylene glycol Monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol isopropyl ether, dipropylene glycol isopropyl ether Tripropylene glycol isopropyl ether, or the like can be used methyl glycol. Further, for the purpose of improving the coating property to the support 6 and the pot life of the composition, additives such as a surfactant, a viscosity modifier and a dispersant can be added as necessary.
<Roll-to-roll process>
The semiconductor electrode layer manufacturing process described above may be performed in a roll-to-roll process. In the manufacturing method of the semiconductor electrode layer according to the first embodiment of the present disclosure, a material having poor heat resistance such as a resin film substrate such as a lightweight, inexpensive and flexible plastic film can be used for the support 6. Thus, it is possible to manufacture the semiconductor electrode layer with high productivity and low cost by the roll-to-roll process. Below, the example which manufactures a semiconductor electrode layer by a roll-to-roll process is demonstrated.
FIG. 3 is a schematic diagram for explaining an example of manufacturing a semiconductor electrode layer by a roll-to-roll process. For example, the film base material 16 is supplied from a film base material 16 (not shown) wound in a roll shape, wound up by a take-up roll 37, and the supplied film base material 16 travels in the arrow direction.
Application of coating liquid, drying / firing process, calendar process, and electromagnetic wave process are sequentially performed on the traveling film base 16.
First, a coating solution containing semiconductor fine particles prepared in advance is intermittently applied to one main surface of the film substrate 16 guided by the roll 31 by an application unit 41 such as a die coater. Next, in the baking furnace 32, the semiconductor fine particle layer applied on one main surface of the film substrate 16 is subjected to a baking process for drying and necking the coating liquid. The firing temperature is preferably equal to or lower than the glass transition point of the material constituting the film substrate 16 and is typically 40 ° C. or higher and 200 ° C. or lower. Moreover, although there is no restriction | limiting in particular in baking time, Usually, it is about 30 seconds or more and 10 hours or less. At this time, necking is promoted, but is not sufficient because it is fired at a low temperature. Necking can be further promoted and characteristics can be improved by electromagnetic wave treatment described later.
Next, the metal oxide semiconductor porous layer is calendered by the back roll 34 and the press roll 35, thereby promoting the contact between the semiconductor fine particles and increasing the transparency of the metal oxide semiconductor porous layer 33. The thickness of 33 is reduced. As a result, for example, the photoelectric conversion efficiency of the dye-sensitized solar cell can be improved. It is preferable that the temperature of the press roll 35 is, for example, less than 150 ° C., the temperature of the back roll 34 is less than 150 ° C., and the linear pressure is more than 0 kg / cm and not more than 500 kg / cm. When the temperature of the press roll 35 and the back roll 34 is equal to or higher than the above temperature, the film substrate 16 tends to be deformed due to heat loss or the like.
Next, the electromagnetic wave processing unit 40 irradiates the metal oxide semiconductor porous layer 33 with electromagnetic waves, and the metal oxide semiconductor porous layer 33 is instantaneously heated to a high temperature. As shown in FIG. 4, the electromagnetic wave processing unit 40 includes an electromagnetic wave irradiation unit 43 such as an infrared heating lamp that irradiates and heats the metal oxide semiconductor porous layer 33 formed on the film substrate 16, and A cooling roll for cooling one main surface of the film base material 16 on which the metal oxide semiconductor porous layer 33 is not formed. The electromagnetic wave irradiation unit 43 irradiates the metal oxide semiconductor porous layer 33 with infrared rays for a short time to promote necking between the semiconductor fine particles. In heating by infrared irradiation, heating can be instantaneously performed at a high temperature, infrared irradiation can be performed on the metal oxide semiconductor porous while the film base 16 is cooled, processing in the atmosphere is possible, etc. Have advantages.
In the cooling roll 36, for example, a refrigerant made of an antifreeze such as ethylene glycol is circulated in the cooling roll 36, and the temperature is, for example, 0 ° C. or less. The surface of the cooling roll 36 is in close contact with one main surface of the film base material 16 on which the semiconductor fine particle layer is not formed, whereby the film base material 16 is cooled. As shown in FIG. 4, for example, an antifreeze liquid layer 47 such as ethanol is preferably provided on the surface of the cooling roll 36. Thereby, the adhesiveness of the surface of the cooling roll 36 and the one main surface of the resin film base material 16 where the semiconductor fine particle layer is not formed can be improved, and the cooling ability for the film base material 16 can be improved. Because.
When a resin film substrate with a transparent conductive layer is used as the film substrate 16 and the transparent conductive layer is an ITO layer, the atmosphere in which the electromagnetic wave treatment is performed is preferably an atmosphere containing no oxygen. Examples of the atmosphere not containing oxygen include an inert gas atmosphere, a vacuum, and a hydrogen atmosphere. ITO tends to increase in resistance because electromagnetic wave treatment in an atmosphere containing oxygen such as in the air eliminates oxygen deficiency and reduces carriers by incorporating oxygen. Therefore, when processing a conductive layer that cannot be baked in an oxygen atmosphere such as ITO, it is necessary to create an atmosphere containing no oxygen. Examples of the inert gas include nitrogen gas, argon gas, helium gas, and the like. For example, an inert gas may be filled in an atmosphere-controllable chamber 44 as shown in FIG. 4, and electromagnetic wave treatment may be performed in this chamber, and inert gas or the like is sprayed onto the film substrate 16. In this way, electromagnetic wave processing may be performed. For example, in an atmosphere containing oxygen, such as an air atmosphere, the resistivity increases when ITO is heated to 250 ° C. or higher. This is because oxygen deficiency is buried and carriers are reduced. Therefore, it is preferable to perform the electromagnetic wave treatment in an atmosphere not containing oxygen.
(Dye-sensitized solar cell)
An electrochemical device configured as a dye-sensitized solar cell will be described as an example of an electrochemical device using the semiconductor electrode layer obtained by the method for manufacturing a semiconductor electrode layer according to the first embodiment of the present disclosure.
FIG. 5 is a cross-sectional view showing an example of the structure of the dye-sensitized solar cell 60. The dye-sensitized solar cell 60 mainly includes a transparent substrate 61, a transparent conductive layer (negative electrode current collector) 62, a semiconductor electrode layer (negative electrode) 63 holding a photosensitizing dye, an electrolyte layer 64, and a counter electrode (positive electrode). 65, a counter substrate 66, a sealing material 67, and the like.
The semiconductor electrode layer 63 is made of the above-described titanium oxide TiO.2Or the like, and a photosensitizing dye is held on the surfaces of the metal oxide semiconductor fine particles 2 and 3 and the like. Since the dye-sensitized solar cell 60 has the semiconductor electrode layer 63 as an electrode, the dye-sensitized solar cell 60 is an electrochemical device that can be manufactured with low weight, low cost, and high productivity using a flexible plastic film or the like as a support. . In addition, since the semiconductor electrode layer 63 has improved conductivity as compared with the semiconductor electrode layer that does not contain the acicular metal oxide semiconductor fine particles 3, photoelectric conversion when a dye-sensitized solar cell is configured. Performance is improved. Furthermore, the acicular metal oxide semiconductor fine particles 3 have a light diffusion function. For this reason, the utilization factor of incident light is improved, and this also improves the photoelectric conversion performance.
Others are the same as the conventional dye-sensitized solar cell. That is, the transparent substrate 61 is made of a glass plate or a plastic film such as PEN or PET. The transparent conductive layer (negative electrode current collector) 62 is made of ITO, FTO, or the like, and is provided on the transparent substrate 61. The electrolyte layer 64 is I−/ I3 −(Triiodide I3 −I2Is iodide ion I−It is a chemical species that exists as an ion in conjunction with. ) And the like, and is disposed between the semiconductor electrode layer 63 and the counter electrode 65 so that the electrolyte solution can infiltrate into the semiconductor electrode layer 63. The counter electrode 65 is made of a platinum layer, a carbon layer, or the like laminated on the base layer, and is provided on the counter substrate 66. The counter substrate 66 is made of a glass plate, a plastic film, or the like.
When the light is incident, the dye-sensitized solar cell 60 operates as a battery having the counter electrode 65 as a positive electrode and the semiconductor electrode layer 63 as a negative electrode.
That is, when the photosensitizing dye absorbs the photons transmitted through the transparent substrate 61 and the transparent conductive layer 62, the electrons in the photosensitizing dye are excited from the ground state to the excited state. Excited electrons are taken out to the conduction band of the semiconductor electrode layer 63 through electrical coupling between the photosensitizing dye and the semiconductor electrode layer 63, and reach the transparent conductive layer 62 through the semiconductor electrode layer 63. To do.
On the other hand, the photosensitizing dye that has lost the electrons is a reducing agent in the electrolyte layer 64, such as I.−To the following reaction
2I−→ I2+ 2e−
I2+ I−→ I3 −
And receive an electron in the electrolyte layer 64 through an oxidant such as I3 −Is generated. The generated oxidant reaches the counter electrode 65 by diffusion, and the reverse reaction of the above reaction.
I3 −→ I2+ I−
I2+ 2e−→ 2I−
Thus, electrons are received from the counter electrode 65 and reduced to the original reducing agent.
The electrons that have flowed from the transparent conductive layer 62 to the external circuit return to the counter electrode 65 after performing electrical work in the external circuit. In this way, light energy is converted into electrical energy without leaving any change in the photosensitizing dye or the electrolyte layer 64.
To produce the dye-sensitized solar cell 60, the semiconductor electrode layer 1 or 21 is formed on the transparent conductive layer 62 provided on the transparent substrate 61 by the method for manufacturing a semiconductor electrode layer described above. Next, the photosensitizing dye is adsorbed on the semiconductor electrode layer 1 or 21 to form the semiconductor electrode layer 1 or 21. The method for adsorbing the dye is not particularly limited. For example, a solution in which a dye molecule is dissolved is prepared, and the transparent substrate 61 on which the semiconductor electrode layer 1 or 21 is formed is immersed in the dye solution, or the semiconductor electrode The dye solution is soaked into the semiconductor electrode layer 1 or 21 by applying, spraying, or dropping the dye solution onto the layer 1 or 21, and then the solvent is evaporated. Next, the transparent substrate 61 and the counter substrate 66 are disposed so that the semiconductor electrode layer 63 and the counter electrode 65 are opposed to each other, and are bonded together via a sealing material 67. Finally, an electrolyte solution is injected to form the electrolyte layer 64.
The semiconductor electrode layer 63 preferably has a large actual surface area including the surface of fine particles facing pores inside the porous layer so that a large amount of photosensitizing dye can be adsorbed. The surface area is preferably 10 times or more with respect to the area (projected area) of the outer surface, and more preferably 100 times or more.
Generally, as the thickness of the semiconductor electrode layer 63 increases and the number of metal oxide semiconductor fine particles 2 and 3 contained per unit projected area increases, the actual surface area increases and the amount of dye that can be held per unit projected area increases. Since it increases, the light absorption rate with respect to incident light becomes high. On the other hand, when the thickness of the semiconductor electrode layer 63 increases, the distance that electrons transferred from the photosensitizing dye to the semiconductor electrode layer 63 diffuse until reaching the transparent conductive layer 62 increases. Electron loss due to charge recombination also increases. Accordingly, the semiconductor electrode layer 63 has a preferable thickness, but is generally 0.1 μm or more and 100 μm or less, and more preferably 1 μm or more and 30 μm or less.
The dye-sensitized solar cell 60 is the same as the conventional dye-sensitized solar cell with respect to members other than the semiconductor electrode layer 63. The main points will be described below.
The photosensitizing dye to be held in the semiconductor electrode layer 63 is not particularly limited as long as it exhibits a sensitizing action. For example, xanthene dyes such as rhodamine B, rose bengal, eosin, erythrosine, merocyanine, quinocyanine, Cyanine dyes such as cryptocyanine, basic dyes such as phenosafranine, cabry blue, thiocin and methylene blue, other azo dyes, porphyrin compounds such as chlorophyll, zinc porphyrin and magnesium porphyrin, phthalocyanine compounds, coumarin compounds, ruthenium Examples include Ru bipyridine complexes, terpyridine complexes, anthraquinone dyes, polycyclic quinone dyes, squarylium dyes, and the like. Among them, a ruthenium Ru bipyridine complex whose ligand has a pyridine ring has a high quantum yield and is preferable as a photosensitizing dye. However, the photosensitizing dye is not limited to this, and can be used alone or in combination of two or more.
As the electrolyte layer 64, an electrolytic solution, or a gel or solid electrolyte can be used. Examples of the electrolyte include a solution containing a redox system (redox couple). Specifically, iodine I2In combination with metal iodide salts or organic iodide salts, bromine Br2And a combination of a metal bromide salt or an organic bromide salt. The cation constituting the metal halide salt is lithium Li+Sodium Na+, Potassium K+, Cesium Cs+, Magnesium Mg2+, And calcium Ca2+The cation constituting the organic halide salt is preferably a quaternary ammonium ion such as tetraalkylammonium ions, pyridinium ions, imidazolium ions, but is not limited thereto. These can be used alone or in combination of two or more.
Especially in the above, iodine I2An electrolyte in which lithium iodide LiI, sodium iodide NaI, or quaternary ammonium compound such as imidazolium iodide is combined is preferable. The concentration of the electrolyte salt in the electrolytic solution is preferably 0.05M or more and 5M or less, more preferably 0.1M or more and 3M or less. Iodine I2Or bromine Br2The concentration of is preferably from 0.0005M to 1M, and more preferably from 0.005M to 0.5M. Various additives such as 4-tert-butylpyridine and carboxylic acid can be added for the purpose of improving the open circuit voltage and the short circuit current.
Solvents that make up the electrolyte include water, alcohols, ethers, esters, carbonates, lactones, carboxylic esters, phosphate triesters, heterocyclic compounds, nitriles, ketones, amides , Nitromethane, halogenated hydrocarbons, dimethyl sulfoxide, sulfolane, N-methylpyrrolidone, 1,3-dimethylimidazolidinone, 3-methyloxazolidinone, and hydrocarbons, but are not limited thereto. It can be used alone or in admixture of two or more. Moreover, it is also possible to use a room temperature ionic liquid of a tetraalkyl, pyridinium, or imidazolium quaternary ammonium salt as a solvent.
In order to reduce the leakage of the electrolyte from the dye-sensitized solar cell 60 and the volatilization of the solvent constituting the electrolyte, a gelling agent, a polymer, a crosslinking monomer, or various shapes of metal oxides are added to the electrolyte composition. Semiconductor fine particles (fibers) or the like can be dissolved or dispersed and mixed to be used as a gel electrolyte. As for the ratio of the gel material and the electrolyte composition, the more the electrolyte composition, the higher the ionic conductivity, but the lower the mechanical strength. On the contrary, when there are too few electrolyte components, although mechanical strength is large, ionic conductivity falls.
There is no particular limitation on the method of injecting the electrolytic solution, but a method of dropping several drops of solution at the inlet and introducing it by capillary action is simple. Further, if necessary, the injection operation can be performed under reduced pressure or under heating. After the solution is completely injected, the solution remaining at the inlet is removed and the inlet is sealed. Although there is no restriction | limiting in particular also in this sealing method, If necessary, it can also seal by sticking a glass plate or a plastic substrate with a sealing material.
When the electrolyte is an electrolyte gelled using a polymer or the like, or an all-solid electrolyte, a polymer solution containing an electrolyte and a plasticizer is applied onto the semiconductor electrode layer 63 by a casting method or the like. . Thereafter, the plasticizer is volatilized and completely removed, and then sealed with a sealing material in the same manner as described above. This sealing is preferably performed using a vacuum sealer or the like in an inert gas atmosphere or in a reduced pressure. After sealing, it is possible to perform heating and pressurizing operations as necessary so that the electrolyte solution of the electrolyte layer 64 can sufficiently penetrate the semiconductor electrode layer 63.
2. Second embodiment
A method for manufacturing an oxide semiconductor layer according to the second embodiment of the present disclosure will be described. The manufacturing method of the oxide semiconductor layer according to the second embodiment of the present disclosure is, for example, a manufacturing method of a transparent oxide semiconductor layer formed on a resin film substrate such as a plastic film.
First, in order to facilitate understanding of the present disclosure, the configuration of a film with a transparent oxide semiconductor layer obtained by the method for manufacturing a transparent oxide semiconductor layer will be described. As shown in FIG. 6, the film with a transparent oxide semiconductor layer has a base film 86 and a transparent oxide semiconductor layer 81 formed on one main surface of the base film 86.
(Transparent oxide semiconductor layer)
As the material of the transparent oxide semiconductor layer 81, known materials can be used. Specifically, ITO, FTO, antimony-doped tin oxide (ATO), tin oxide, zinc oxide, indium / zinc composite oxide (IZO) etc. are mentioned, However, It is not limited to these. The transparent oxide semiconductor layer 81 may be a single layer film or a laminated film of these materials, and two or more kinds of materials may be used in combination.
(Base film)
As the base film 86, triacetyl cellulose (TAC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyester (TPEE), polyimide (PI), polyamide (PA), aramid, polyethylene (PE), Polyacrylate, polyethersulfone, polysulfone, polypropylene (PP), diacetylcellulose, polyvinyl chloride, acrylic resin (PMMA), polycarbonate (PC), epoxy resin, urea resin, urethane resin, melamine resin, and cycloolefin polymer resin ( A resin film substrate such as a transparent plastic film made of a polymer material such as (COP) can be used.
Next, a method for manufacturing the above-described transparent oxide semiconductor layer 81 will be described.
<Formation of transparent oxide semiconductor layer>
The transparent oxide semiconductor layer 81 is formed on one main surface of the base film 86 by, for example, a vapor phase such as a PVD (Physical Vapor Deposition) method or a CVD (Chemical Vapor Deposition) method. It can be formed by the method. Moreover, it can form by liquid phase methods, such as electroplating, electroless plating, the apply | coating method, and a sol-gel method. Further, it can be formed by a solid phase method such as an SPE (solid phase epitaxy) method or an LB (Langmuir-Blodgett) method.
<Electromagnetic wave treatment>
After forming the transparent oxide semiconductor layer 81, electromagnetic wave treatment is performed to promote necking of the transparent oxide semiconductor particles, which are transparent conductive particles. Since a plastic material, which is a base material having a low softening point such as a film material, is used as the material of the base film 86, the base film 86 is damaged by being irradiated with electromagnetic waves while cooling the base film 86. It is possible to reduce resistance by promoting necking without giving.
Electromagnetic waves include infrared rays, ultraviolet rays and visible rays. Other irradiation type treatments include microwave treatment, flame treatment, plasma treatment in air, plasma treatment in vacuum, corona treatment, induction heating treatment and the like, and these methods may be used.
When heating the transparent oxide semiconductor layer 81 at a temperature higher than the temperature at which the film is altered or deformed, in order to suppress the temperature of the film from being higher than the temperature at which the film is altered or deformed by heating, support is provided. It is preferable to perform the treatment while cooling the body (film).
The cooling of the support may be performed by bringing a cooling plate such as a copper plate and a cooling member such as a cooling roll into close contact with the surface of the base film 86 where the transparent oxide semiconductor layer 81 is not formed. For example, when using a cooling plate, it mounts on the cooling plate of the base film 86 in which the transparent oxide semiconductor layer 81 was formed. At this time, the surface of the base film 86 where the transparent oxide semiconductor layer 81 is not formed is a surface that is in close contact with the cooling plate. And while irradiating electromagnetic waves with respect to the transparent oxide semiconductor layer 81, the base film 86 is cooled from the surface side of the side in which the semiconductor fine particle film of the base film 86 is not formed with a cooling plate.
For example, when using a cooling roll, the surface of the cooling roll 36 is brought into close contact with one main surface of the base film 86 where the transparent oxide semiconductor layer 81 is not formed. Cooling takes place. In the cooling roll 36, for example, a refrigerant composed of an antifreeze such as ethylene glycol is circulated in the cooling roll 36, and the temperature is, for example, 0 ° C. or less.
It is preferable to provide an antifreeze layer 47 such as ethanol on the surface of the cooling roll 36. Thereby, the adhesiveness of the surface of the cooling roll 36 and the one main surface of the base film 86 on the side where the transparent oxide semiconductor layer 81 is not formed can be improved, and the cooling ability for the base film 86 can be improved. It is because it can improve.
When ITO is used as the transparent oxide semiconductor layer 81, it is preferable that the atmosphere in which the electromagnetic wave treatment is performed is an atmosphere not containing oxygen. Examples of the atmosphere not containing oxygen include an inert gas atmosphere, a vacuum, and a hydrogen atmosphere. ITO that is used as the transparent oxide semiconductor layer 81 has an increased resistance because an oxygen deficiency disappears and carriers are reduced by incorporating oxygen in an electromagnetic wave treatment in an atmosphere containing oxygen such as in the air. There is a tendency. Therefore, when ITO is used as the transparent oxide semiconductor layer 81, it is necessary to create an atmosphere that does not contain oxygen when heating by electromagnetic wave treatment is performed. Examples of the inert gas include nitrogen gas, argon gas, helium gas, and the like. For example, the atmosphere in which the electromagnetic wave treatment is performed may be controlled by performing the electromagnetic wave treatment in a chamber capable of controlling the atmosphere, or by performing the electromagnetic wave treatment by blowing an inert gas or the like onto the support. The atmosphere for performing the electromagnetic wave treatment may be controlled.
The manufacturing process of the transparent oxide semiconductor layer 81 described above may be performed in a roll-to-roll process. In the method for manufacturing the transparent oxide semiconductor layer 81 according to the second embodiment of the present disclosure, a material having poor heat resistance, such as a lightweight, inexpensive, and flexible plastic film, can be used as a support. By the roll process, it is possible to produce a film with a transparent oxide semiconductor layer at a low cost with high productivity.
　以下、本開示の実施例について説明するが、本開示は下記実施例に限定されるものではない。
［実施例１］
　非特許文献（Ａｄｖ．Ｍａｔｅｒ．２００３，１５，２１０１）を参考にして、以下のように色素増感型太陽電池（対向セル）を作製した。
＜塗液の調製＞
　粒状の金属酸化物半導体微粒子２として、第１の粒状酸化チタン微粒子２Ａを用いた。第１の粒状酸化チタン微粒子２Ａとして、Ｐ２５（商品名；デグサ社製、アナターゼ型結晶（８０％）とルチル型結晶（２０％）の混合物、一次粒子の平均粒径　約２１ｎｍ）を用いた。
　この微粒子粉末を、酸化チタン含有率が３０質量％になるようにエタノールと混合し、直径０．６５ｍｍのジルコニアビーズとを用いて、アジターにて２４時間ビーズ分散処理を行い、粒状の金属酸化物半導体微粒子２の分散液を調製した。
　次に、この分散液に所定量の第１の化合物を加え、攪拌して均一に混合し、濃度調整のために溶媒を追加し、第１の酸化チタン微粒子２Ａ、並びに第１の化合物を含有する塗液を調製した。このとき、第１の化合物の添加によって分散液の粘度が増加することが観察された。
　この際、第１の化合物としてブトキシチタンダイマー（三菱ガス化学（株）製）を用い、塗液における配合量を２．５質量％で一定とした。溶媒は、いずれの例でもエタノールを用いた。
＜半導体電極（金属酸化物半導体多孔質層）の作製＞
　支持体として、表面抵抗１２Ω／□以上１５Ω／□以下のＩＴＯ層付ＰＥＴフィルム（尾池工業株式会社製）を用いた。この支持体上にコイルバー（＃４４）を用いてバーコート法によって上記塗液を塗布した後、室温で乾燥させた。
＜カレンダー処理＞
　次に、図７に示すように、バックロール３４とプレスロール３５との間に、半導体微粒子層が形成されたＩＴＯ／ＰＥＴフィルムを挟んだ状態で連続的に回転しながら加圧して、半導体微粒子層にカレンダー処理を行った。具体的には、バックロール３４とプレスロール３５はともに線圧１０００Ｎ／１５ｍｍで上記半導体微粒子層付ＩＴＯ／ＰＥＴフィルムをニップした。これにより、半導体微粒子層を連続的にカレンダー処理した。カレンダー処理回数は１回とした。これにより、支持体（ＩＴＯ／ＰＥＴフィルム）と半導体微粒子層との密着性が向上し、また、微粒子間の隙間が埋まり接触抵抗が下がる効果が得られる。
　その後、半導体微粒子層を、ガラス板のエッジで削って５ｍｍ×５ｍｍの大きさとした後、１５０℃で３０分間焼成し、金属酸化物半導体多孔質層を得た。
＜赤外線処理（ＩＲ処理）＞
　次に、ＩＴＯ／ＰＥＴフィルムの一主面に形成された金属酸化物半導体多孔質層に対して、赤外線放射加熱器（製品名ＩＲ２９８、（株）サーモ理工社製）を用いて、赤外線照射（電流出力値２０Ａ、処理時間１秒間）を行い加熱すると共に、ＩＴＯ／ＰＥＴフィルムの他の主面を、冷却銅板に密着させて、ＩＴＯ／ＰＥＴフィルムを冷却した。このとき、冷却銅板に常温のエタノールを垂らし、冷却銅板とＩＴＯ／ＰＥＴフィルムの他の主面との間にエタノールからなる冷却媒層を設けた。また、金属酸化物半導体多孔質層が形成されたＩＴＯ／ＰＥＴフィルムに対して、Ａｒガスを吹き付けた。なお、冷却水循環装置を用いて、冷却銅板の内部に冷却液を流通させ、装置の冷却液の設定温度を−１０℃に設定し、冷却液としては、エチレングリコールを用いた。
＜色素吸着＞
　次に、室温にて１０時間金属酸化物半導体多孔質層を有機色素（Ｄ３５８）溶液に浸漬し、金属酸化物半導体多孔質層に色素を吸着させた。Ｄ３５８色素溶液は、Ｄ３５８色素（商品名；三菱製紙（株）製）を０．５ｍＭの濃度で、アセトニトリルとｔｅｒｔ−ブチルアルコールとを１：１の体積比で混合した混合溶媒に溶解させた溶液である。次に、アセトニトリルを用いてこの半導体電極（金属酸化物半導体多孔質層）を洗浄した後、アセトニトリルを自然蒸発させ、半導体電極を乾燥させた。
＜対向電極＞
　一方、対向電極には、ＳＵＳ３１６基板にカーボン対極を成型したものを用いた。
＜組み立て＞
　次に、半導体電極層と対向電極とが向かい合うように、上記２枚の基板を配置し、厚さ３０μｍのシリコンゴムシートを介して貼り合わせた。次に、毛細管現象を利用して電極間に電解液を導入し、色素増感型太陽電池を作製した。電解液として、３−メトキシプロピオニトリルに０．６Ｍのヨウ化（１−プロピル−３−メチルイミダゾリウム）と０．１Ｍのヨウ素とを溶解させた溶液を用いた。
＜色素増感型太陽電池の評価＞
（光電変換効率）
　４．５ｍｍ×４．５ｍｍの角孔のあいた正方形マスクを用いて擬似太陽光（ＡＭ１．５、１００ｍＷ／ｃｍ２）を照射しながら、作製した色素増感型太陽電池の短絡電流（ＪＣＳ）、開放電圧（ＶＯＣ）、フィルファクタ（ＦＦ）、光電変換効率（η）、直列抵抗値（Ｒｓ）を２４℃にて評価した。
［実施例２］
＜塗液の調製＞
（第１の塗液）
　粒状の金属酸化物半導体微粒子２である第１の粒状微粒子２Ａおよび第２の粒状微粒子２Ｂとして、いずれも球状で、大きさが異なる２種類の酸化チタンＴｉＯ２微粒子を用いた。第１の粒状微粒子２Ａとして、Ｐ２５（商品名；デグサ社製、アナターゼ型結晶（８０％）とルチル型結晶（２０％）の混合物、一次粒子の平均粒径　約２１ｎｍ）を用いた。
　この微粒子粉末を、酸化チタン含有率が１４質量％になるようにエタノールと混合し、直径０．６５ｍｍのジルコニアビーズとを用いて、アジターにて２４時間ビーズ分散処理を行い、第１の粒状酸化チタン微粒子２Ａの分散液を調製した。
　また、第２の粒状微粒子２Ｂとして、ＴＡ−３００（商品名；富士チタン工業（株）製、アナターゼ型結晶、一次粒子の平均粒径　約３９０ｎｍ）を用いた。この微粒子粉末を、酸化チタン含有率が３．５質量％になるようにエタノールと混合し、直径０．６５ｍｍのジルコニアビーズとを用いて、アジターにて２４時間ビーズ分散処理を行い、第２の粒状酸化チタン微粒子２Ｂの分散液を調製した。
　次に各微粒子の分散液を所定の比率で混合した。次に、この分散液に所定量の第１の化合物を加え、攪拌して均一に混合し、濃度調整のために溶媒を追加し、酸化チタン微粒子２Ａおよび２Ｂ、並びに第１の化合物を含有する塗液を調製した。このとき、第１の化合物の添加によって分散液の粘度が増加することが観察された。
　この際、第１の化合物としてブトキシチタンダイマー（三菱ガス化学（株）製）を用い、塗液における配合量を２．５質量％で一定とした。溶媒は、いずれの例でもエタノールを用いた。
（第２の塗液）
　粒状の金属酸化物半導体微粒子２である第１の粒状微粒子２Ａおよび第２の粒状微粒子２Ｂとして、いずれも球状で、大きさが異なる２種類の酸化チタンＴｉＯ２微粒子を用いた。第１の粒状微粒子２Ａとして、Ｐ２５（商品名；デグサ社製、アナターゼ型結晶（８０％）とルチル型結晶（２０％）の混合物、一次粒子の平均粒径　約２１ｎｍ）を用いた。
　この微粒子粉末を、酸化チタン含有率が１０．５質量％になるようにエタノールと混合し、直径０．６５ｍｍのジルコニアビーズとを用いて、アジターにて２４時間ビーズ分散処理を行い、第１の粒状酸化チタン微粒子２Ａの分散液を調製した。
　また、第２の粒状微粒子２Ｂとして、ＴＡ−３００（商品名；富士チタン工業（株）製、アナターゼ型結晶、一次粒子の平均粒径　約３９０ｎｍ）を用いた。この微粒子粉末を、酸化チタン含有率が５．２５質量％になるようにエタノールと混合し、直径０．６５ｍｍのジルコニアビーズとを用いて、アジターにて２４時間ビーズ分散処理を行い、第２の粒状酸化チタン微粒子２Ｂの分散液を調製した。
　一方、針状の金属酸化物半導体微粒子３として、針状の酸化チタンＴｉＯ２微粒子を用いた。針状の酸化チタン微粒子としては、ＦＴＬ−３００（商品名；石原産業（株）製、ルチル型結晶、一次粒子の平均直径　約０．２７μｍ、平均長さ　約５．１５μｍ）を用いた。この微粒子粉末を、酸化チタン含有率が１．７５質量％になるようにエタノールと混合し、直径０．６５ｍｍのジルコニアビーズとを用いて、ペイントシェイカーにて２４時間ビーズ分散処理を行い、針状の金属酸化物半導体微粒子３の分散液を調製した。
　次に各微粒子の分散液を所定の比率で混合した。次に、この分散液に所定量の第１の化合物を加え、攪拌して均一に混合し、濃度調整のために溶媒を追加し、酸化チタン微粒子２Ａ、２Ｂおよび３、並びに第１の化合物を含有する塗液を調製した。このとき、第１の化合物の添加によって分散液の粘度が増加することが観察された。
　この際、第１の化合物としてブトキシチタンダイマー（三菱ガス化学（株）製）を用い、塗液における配合量を２．５質量％で一定とした。溶媒は、いずれの例でもエタノールを用いた。
＜半導体電極（金属酸化物半導体多孔質層）の作製＞
　以下のようにして、支持体６上に、２層の半導体微粒子層を形成した。支持体６として、表面抵抗１２~１５Ω／□のＩＴＯ層付ＰＥＴフィルム（尾池工業株式会社製）を用いた。この支持体６上にコイルバー（＃３０）を用いてバーコート法によって第１の塗液を塗布した後、室温で乾燥させることにより、支持体上に第１の半導体微粒子層を形成した。
　次に、支持体上に形成された第１の半導体微粒子層上にコイルバー（＃１４）を用いてバーコート法によって第２の塗液を塗布した後、室温で乾燥させることにより、第２の半導体微粒子層を形成した。
　その後の工程は、実施例１と同様にして、色素増感型太陽電池を作製し、実施例１と同様の評価を行った。
［実施例３］
＜塗液の調製＞
　粒状の金属酸化物半導体微粒子２である第１の粒状微粒子２Ａおよび第２の粒状微粒子２Ｂとして、いずれも球状で、大きさが異なる２種類の酸化チタンＴｉＯ２微粒子を用いた。第１の粒状微粒子２Ａとして、Ｐ２５（商品名；デグサ社製、アナターゼ型結晶（８０％）とルチル型結晶（２０％）の混合物、一次粒子の平均粒径　約２１ｎｍ）を用いた。
　この微粒子粉末を、酸化チタン含有率が１４質量％になるようにエタノールと混合し、直径０．６５ｍｍのジルコニアビーズとを用いて、アジターにて２４時間ビーズ分散処理を行い、第１の粒状酸化チタン微粒子２Ａの分散液を調製した。
　また、第２の粒状微粒子２Ｂとして、ＴＡ−３００（商品名；富士チタン工業（株）製、アナターゼ型結晶、一次粒子の平均粒径　約３９０ｎｍ）を用いた。この微粒子粉末を、酸化チタン含有率が３．５質量％になるようにエタノールと混合し、直径０．６５ｍｍのジルコニアビーズとを用いて、アジターにて２４時間ビーズ分散処理を行い、第２の粒状酸化チタン微粒子２Ｂの分散液を調製した。
　次に各微粒子の分散液を所定の比率で混合した。次に、この分散液に所定量の第１の化合物を加え、攪拌して均一に混合し、濃度調整のために溶媒を追加し、酸化チタン微粒子２Ａおよび２Ｂ、並びに第１の化合物を含有する塗液を調製した。このとき、第１の化合物の添加によって分散液の粘度が増加することが観察された。
　この際、第１の化合物としてブトキシチタンダイマー（三菱ガス化学（株）製）を用い、塗液における配合量を２．５質量％で一定とした。溶媒は、いずれの例でもエタノールを用いた。
＜半導体電極層（金属酸化物半導体多孔質層）の作製＞
　支持体として、ＦＴＯ層付ガラス基板（日本板硝子（株）製、表面抵抗１０Ω／□）を用いた。この支持体上に、コイルバー（＃４４）を用いてバーコート法によって、上記塗液を塗布した後、室温で乾燥させた。
　次に、半導体微粒子層をプレス機で１０ｔ／３７．５ｍｍ２の面圧で処理した。これにより、基材と半導体微粒子層との密着性が向上し、また、微粒子間の隙間が埋まり接触抵抗が下がる効果が得られる。この半導体微粒子層を、ガラス板のエッジで削って５ｍｍ×５ｍｍの大きさとした後、１５０℃で３０分焼成し、金属酸化物半導体多孔質層を得た。
＜赤外線処理＞
　次に、ＦＴＯ層付ガラス基板の一主面に形成された半導体微粒子層に対して、赤外線放射加熱器（製品名ＩＲ２９８、（株）サーモ理工社製）を用いて、大気中において、赤外線照射（電流出力値２０Ａ、処理時間１秒間）を行い加熱すると共に、ＦＴＯ層付ガラス基板の他の主面を、冷却銅板に密着させて、ＦＴＯ層付ガラス基板を冷却した。このとき、冷却銅板に常温のエタノールを垂らし、冷却銅板とＦＴＯ層付ガラス基板の他の主面との間にエタノールからなる冷却媒層を設けた。なお、冷却水循環装置を用いて、冷却銅板の内部に工業用水を流通させ、装置の冷却液の設定温度を３５℃に設定した。
　その後の工程を実施例１と同様にして、色素増感型太陽電池を作製し、実施例１と同様の評価を行った。
［比較例１~比較例３］
　赤外線照射処理を行わなかったこと以外は、実施例１~実施例３のそれぞれと同様にして、半導体電極層および色素増感型太陽電池を作製し、実施例１と同様の評価を行った。
　評価結果を図８および表１に示す。表１には、実施例１~実施例３および比較例１~比較例３の開放電圧（ＶＯＣ）、短絡電流（ＪＳＣ）、フィルファクター（ＦＦ）、光電変換効率（η）、直列抵抗値（Ｒｓ）を示す。
Figure JPOXMLDOC01-appb-T000002
 　図８は、光変換効率測定時のＩ−Ｖ曲線である。○は、電磁波照射処理を施して作製した実施例１の対向セルのＩ−Ｖ曲線であり、□は電磁波照射処理を施さずに作製した比較例１の対向セルのＩ−Ｖ曲線である。図８に示すように、電磁波照射処理を施した対向セルの結果では、電磁波照射処理を施していない結果よりも、電流密度が上にシフトしている。つまり、電磁波照射処理を施すことによって半導体微粒子同士の結合が改善して抵抗が減少し、その結果、電流密度が増大したことによると考えられる。表１に示すように、電磁波照射処理を施した対向セルの性能（実施例１~実施例３）は、電磁波照射処理を施していない対向セルの性能（比較例１~比較例３）より優れていることが確認できる。
３．他の実施の形態
　本開示は、上述した本開示の実施の形態に限定されるものでは無く、本開示の要旨を逸脱しない範囲内で様々な変形や応用が可能である。例えば、上述の実施の形態および実施例において挙げた数値、構造、形状、材料、原料、プロセス等はあくまでも例に過ぎず、必要に応じてこれらと異なる数値、構造、形状、材料、原料、プロセス等を用いてもよい。 Hereinafter, examples of the present disclosure will be described, but the present disclosure is not limited to the following examples.
[Example 1]
With reference to non-patent literature (Adv. Mater. 2003, 15, 2101), a dye-sensitized solar cell (opposing cell) was produced as follows.
<Preparation of coating liquid>
As the granular metal oxide semiconductor fine particles 2, the first granular titanium oxide fine particles 2A were used. As the first granular titanium oxide fine particles 2A, P25 (trade name; manufactured by Degussa, a mixture of anatase type crystal (80%) and rutile type crystal (20%), average particle size of primary particles is about 21 nm) was used.
This fine particle powder is mixed with ethanol so that the titanium oxide content is 30% by mass, and is subjected to a bead dispersion treatment with an agitator for 24 hours using zirconia beads having a diameter of 0.65 mm to form a granular metal oxide. A dispersion of semiconductor fine particles 2 was prepared.
Next, a predetermined amount of the first compound is added to the dispersion, stirred and mixed uniformly, a solvent is added to adjust the concentration, and the first titanium oxide fine particles 2A and the first compound are contained. A coating solution was prepared. At this time, it was observed that the viscosity of the dispersion increased by the addition of the first compound.
At this time, butoxy titanium dimer (Mitsubishi Gas Chemical Co., Ltd.) was used as the first compound, and the blending amount in the coating liquid was kept constant at 2.5% by mass. As a solvent, ethanol was used in all examples.
<Preparation of semiconductor electrode (metal oxide semiconductor porous layer)>
As the support, a PET film with an ITO layer (manufactured by Oike Industry Co., Ltd.) having a surface resistance of 12Ω / □ or more and 15Ω / □ or less was used. The coating solution was applied to the support by a bar coating method using a coil bar (# 44) and then dried at room temperature.
<Calendar processing>
Next, as shown in FIG. 7, between the back roll 34 and the press roll 35, pressurizing while continuously rotating while sandwiching the ITO / PET film on which the semiconductor fine particle layer is formed, the semiconductor fine particles The layer was calendered. Specifically, both the back roll 34 and the press roll 35 nipped the ITO / PET film with a semiconductor fine particle layer at a linear pressure of 1000 N / 15 mm. Thus, the semiconductor fine particle layer was continuously calendered. The number of calendar processes was one. Thereby, the adhesiveness of a support body (ITO / PET film) and a semiconductor fine particle layer improves, The clearance gap between fine particles is filled, and the effect that contact resistance falls is acquired.
Thereafter, the semiconductor fine particle layer was cut at the edge of the glass plate to a size of 5 mm × 5 mm, and then fired at 150 ° C. for 30 minutes to obtain a metal oxide semiconductor porous layer.
<Infrared treatment (IR treatment)>
Next, the metal oxide semiconductor porous layer formed on one main surface of the ITO / PET film is irradiated with infrared rays using an infrared radiation heater (product name IR298, manufactured by Thermo Riko Co., Ltd.). Current output value 20A, treatment time 1 second) was performed and heated, and the other main surface of the ITO / PET film was brought into close contact with the cooling copper plate to cool the ITO / PET film. At this time, normal temperature ethanol was hung on the cooling copper plate, and a cooling medium layer made of ethanol was provided between the cooling copper plate and the other main surface of the ITO / PET film. Moreover, Ar gas was sprayed with respect to the ITO / PET film in which the metal oxide semiconductor porous layer was formed. In addition, the cooling fluid was circulated through the inside of the cooling copper plate using the cooling water circulation device, the set temperature of the cooling fluid of the device was set to −10 ° C., and ethylene glycol was used as the cooling fluid.
<Dye adsorption>
Next, the metal oxide semiconductor porous layer was immersed in an organic dye (D358) solution at room temperature for 10 hours to adsorb the dye to the metal oxide semiconductor porous layer. D358 dye solution is a solution prepared by dissolving D358 dye (trade name; manufactured by Mitsubishi Paper Industries Co., Ltd.) in a mixed solvent in which acetonitrile and tert-butyl alcohol are mixed at a volume ratio of 1: 1 at a concentration of 0.5 mM. It is. Next, after this semiconductor electrode (metal oxide semiconductor porous layer) was washed with acetonitrile, the acetonitrile was naturally evaporated and the semiconductor electrode was dried.
<Counter electrode>
On the other hand, the counter electrode used was a carbon counter electrode formed on a SUS316 substrate.
<Assembly>
Next, the two substrates were placed so that the semiconductor electrode layer and the counter electrode face each other, and bonded together via a silicon rubber sheet having a thickness of 30 μm. Next, an electrolyte solution was introduced between the electrodes using a capillary phenomenon to produce a dye-sensitized solar cell. As an electrolytic solution, a solution in which 0.6 M iodide (1-propyl-3-methylimidazolium) and 0.1 M iodine were dissolved in 3-methoxypropionitrile was used.
<Evaluation of dye-sensitized solar cell>
(Photoelectric conversion efficiency)
Short circuit current (JCS) of the produced dye-sensitized solar cell while irradiating simulated sunlight (AM1.5, 100 mW / cm 2 ) using a square mask having a 4.5 mm × 4.5 mm square hole, The open circuit voltage (VOC), fill factor (FF), photoelectric conversion efficiency (η), and series resistance value (Rs) were evaluated at 24 ° C.
[Example 2]
<Preparation of coating liquid>
(First coating liquid)
As the first granular fine particles 2A and the second granular fine particles 2B, which are the granular metal oxide semiconductor fine particles 2, two types of titanium oxide TiO 2 fine particles having a spherical shape and different sizes were used. As the first granular fine particles 2A, P25 (trade name; manufactured by Degussa, a mixture of anatase type crystal (80%) and rutile type crystal (20%), average particle size of primary particles is about 21 nm) was used.
This fine particle powder is mixed with ethanol so that the titanium oxide content is 14% by mass, and is subjected to bead dispersion treatment with an agitator for 24 hours using zirconia beads having a diameter of 0.65 mm, and the first granular oxidation. A dispersion of titanium fine particles 2A was prepared.
Further, TA-300 (trade name: manufactured by Fuji Titanium Industry Co., Ltd., anatase type crystal, average particle size of primary particles of about 390 nm) was used as the second granular fine particles 2B. This fine particle powder was mixed with ethanol so that the titanium oxide content was 3.5% by mass, and was subjected to bead dispersion treatment with an agitator for 24 hours using zirconia beads having a diameter of 0.65 mm. A dispersion of granular titanium oxide fine particles 2B was prepared.
Next, each fine particle dispersion was mixed in a predetermined ratio. Next, a predetermined amount of the first compound is added to the dispersion, stirred and mixed uniformly, a solvent is added to adjust the concentration, and the titanium oxide fine particles 2A and 2B and the first compound are contained. A coating solution was prepared. At this time, it was observed that the viscosity of the dispersion increased by the addition of the first compound.
At this time, butoxy titanium dimer (Mitsubishi Gas Chemical Co., Ltd.) was used as the first compound, and the blending amount in the coating liquid was kept constant at 2.5% by mass. As a solvent, ethanol was used in all examples.
(Second coating liquid)
As the first granular fine particles 2A and the second granular fine particles 2B, which are the granular metal oxide semiconductor fine particles 2, two types of titanium oxide TiO 2 fine particles having a spherical shape and different sizes were used. As the first granular fine particles 2A, P25 (trade name; manufactured by Degussa, a mixture of anatase type crystal (80%) and rutile type crystal (20%), average particle size of primary particles is about 21 nm) was used.
This fine particle powder was mixed with ethanol so that the titanium oxide content was 10.5% by mass, and the beads were dispersed with an agitator for 24 hours using zirconia beads having a diameter of 0.65 mm. A dispersion of granular titanium oxide fine particles 2A was prepared.
Further, TA-300 (trade name: manufactured by Fuji Titanium Industry Co., Ltd., anatase type crystal, average particle size of primary particles of about 390 nm) was used as the second granular fine particles 2B. This fine particle powder was mixed with ethanol so that the titanium oxide content was 5.25% by mass, and was subjected to bead dispersion treatment with an agitator for 24 hours using zirconia beads having a diameter of 0.65 mm. A dispersion of granular titanium oxide fine particles 2B was prepared.
On the other hand, acicular titanium oxide TiO 2 fine particles were used as the acicular metal oxide semiconductor fine particles 3. As the acicular titanium oxide fine particles, FTL-300 (trade name; manufactured by Ishihara Sangyo Co., Ltd., rutile type crystal, average primary particle diameter of about 0.27 μm, average length of about 5.15 μm) was used. This fine particle powder is mixed with ethanol so that the titanium oxide content is 1.75% by mass, and the beads are dispersed with a zirconia bead having a diameter of 0.65 mm for 24 hours using a paint shaker. A dispersion of the metal oxide semiconductor fine particles 3 was prepared.
Next, each fine particle dispersion was mixed in a predetermined ratio. Next, a predetermined amount of the first compound is added to the dispersion, stirred and mixed uniformly, a solvent is added to adjust the concentration, and the titanium oxide fine particles 2A, 2B and 3 and the first compound are added. A coating liquid containing was prepared. At this time, it was observed that the viscosity of the dispersion increased by the addition of the first compound.
At this time, butoxy titanium dimer (Mitsubishi Gas Chemical Co., Ltd.) was used as the first compound, and the blending amount in the coating liquid was kept constant at 2.5% by mass. As a solvent, ethanol was used in all examples.
<Preparation of semiconductor electrode (metal oxide semiconductor porous layer)>
Two semiconductor fine particle layers were formed on the support 6 as follows. As the support 6, a PET film with an ITO layer having a surface resistance of 12 to 15Ω / □ (manufactured by Oike Industry Co., Ltd.) was used. A first coating liquid was applied on the support 6 by a bar coating method using a coil bar (# 30), and then dried at room temperature, thereby forming a first semiconductor fine particle layer on the support.
Next, a second coating liquid is applied by a bar coating method using a coil bar (# 14) on the first semiconductor fine particle layer formed on the support, and then dried at room temperature, whereby the second A semiconductor fine particle layer was formed.
Subsequent steps were carried out in the same manner as in Example 1 to produce a dye-sensitized solar cell and evaluated in the same manner as in Example 1.
[Example 3]
<Preparation of coating liquid>
As the first granular fine particles 2A and the second granular fine particles 2B, which are the granular metal oxide semiconductor fine particles 2, two types of titanium oxide TiO 2 fine particles having a spherical shape and different sizes were used. As the first granular fine particles 2A, P25 (trade name; manufactured by Degussa, a mixture of anatase type crystal (80%) and rutile type crystal (20%), average particle size of primary particles is about 21 nm) was used.
This fine particle powder is mixed with ethanol so that the titanium oxide content is 14% by mass, and is subjected to bead dispersion treatment with an agitator for 24 hours using zirconia beads having a diameter of 0.65 mm, and the first granular oxidation. A dispersion of titanium fine particles 2A was prepared.
Further, TA-300 (trade name: manufactured by Fuji Titanium Industry Co., Ltd., anatase type crystal, average particle size of primary particles of about 390 nm) was used as the second granular fine particles 2B. This fine particle powder was mixed with ethanol so that the titanium oxide content was 3.5% by mass, and was subjected to bead dispersion treatment with an agitator for 24 hours using zirconia beads having a diameter of 0.65 mm. A dispersion of granular titanium oxide fine particles 2B was prepared.
Next, each fine particle dispersion was mixed in a predetermined ratio. Next, a predetermined amount of the first compound is added to the dispersion, stirred and mixed uniformly, a solvent is added to adjust the concentration, and the titanium oxide fine particles 2A and 2B and the first compound are contained. A coating solution was prepared. At this time, it was observed that the viscosity of the dispersion increased by the addition of the first compound.
At this time, butoxy titanium dimer (Mitsubishi Gas Chemical Co., Ltd.) was used as the first compound, and the blending amount in the coating liquid was kept constant at 2.5% by mass. As a solvent, ethanol was used in all examples.
<Preparation of semiconductor electrode layer (metal oxide semiconductor porous layer)>
A glass substrate with an FTO layer (manufactured by Nippon Sheet Glass Co., Ltd., surface resistance 10Ω / □) was used as the support. On the support, the above coating solution was applied by a bar coating method using a coil bar (# 44) and then dried at room temperature.
Next, the semiconductor fine particle layer was processed with a press at a surface pressure of 10 t / 37.5 mm 2 . Thereby, the adhesiveness of a base material and a semiconductor fine particle layer improves, The clearance gap between fine particles is filled, and the effect that contact resistance falls is acquired. The semiconductor fine particle layer was shaved with an edge of a glass plate to a size of 5 mm × 5 mm, and then fired at 150 ° C. for 30 minutes to obtain a metal oxide semiconductor porous layer.
<Infrared treatment>
Next, the semiconductor fine particle layer formed on one main surface of the glass substrate with an FTO layer is irradiated with infrared rays in the atmosphere using an infrared radiation heater (product name IR298, manufactured by Thermo Riko Co., Ltd.). While heating by performing (current output value 20A, processing time 1 second), the other main surface of the glass substrate with FTO layer was brought into close contact with the cooling copper plate to cool the glass substrate with FTO layer. At this time, normal temperature ethanol was hung on the cooling copper plate, and a cooling medium layer made of ethanol was provided between the cooling copper plate and the other main surface of the glass substrate with the FTO layer. In addition, the industrial water was distribute | circulated inside the cooling copper plate using the cooling water circulation apparatus, and the preset temperature of the cooling liquid of the apparatus was set to 35 degreeC.
Subsequent steps were performed in the same manner as in Example 1 to produce a dye-sensitized solar cell, and the same evaluation as in Example 1 was performed.
[Comparative Examples 1 to 3]
A semiconductor electrode layer and a dye-sensitized solar cell were produced in the same manner as in Examples 1 to 3 except that the infrared irradiation treatment was not performed, and the same evaluation as in Example 1 was performed.
The evaluation results are shown in FIG. Table 1 shows the open-circuit voltage (VOC), short-circuit current (JSC), fill factor (FF), photoelectric conversion efficiency (η), and series resistance value of Examples 1 to 3 and Comparative Examples 1 to 3 ( Rs).
Figure JPOXMLDOC01-appb-T000002
 FIG. 8 is an IV curve when measuring the light conversion efficiency. ○ is the IV curve of the counter cell of Example 1 prepared by performing the electromagnetic wave irradiation treatment, and □ is the IV curve of the counter cell of Comparative Example 1 manufactured without performing the electromagnetic wave irradiation treatment. As shown in FIG. 8, in the result of the counter cell subjected to the electromagnetic wave irradiation process, the current density is shifted upward as compared with the result of not performing the electromagnetic wave irradiation process. That is, it is considered that the application of electromagnetic wave irradiation improves the bonding between the semiconductor fine particles and decreases the resistance, resulting in an increase in current density. As shown in Table 1, the performance of the counter cell subjected to the electromagnetic wave irradiation treatment (Examples 1 to 3) is superior to the performance of the counter cell not subjected to the electromagnetic wave irradiation treatment (Comparative Examples 1 to 3). Can be confirmed.
3. Other Embodiments The present disclosure is not limited to the above-described embodiments of the present disclosure, and various modifications and applications are possible without departing from the gist of the present disclosure. For example, the numerical values, structures, shapes, materials, raw materials, processes, and the like given in the above-described embodiments and examples are merely examples, and numerical values, structures, shapes, materials, raw materials, processes that are different from these as necessary. Etc. may be used.
　１・・・半導体電極層
　２、３・・・金属酸化物半導体微粒子
　２Ａ・・・第１の粒状微粒子
　２Ｂ・・・第２の粒状微粒子
　４・・・第１酸化物層
　５・・・第２酸化物層
　６・・・支持体
　７・・・密着補助層
　１６・・・フィルム基材
　２１・・・半導体電極層
　３１・・・ロール
　３２・・・焼成炉
　３３・・・金属酸化物半導体多孔質層
　３４・・・バックロール
　３５・・・プレスロール
　３６・・・冷却ロール
　３７・・・巻き取りロール
　４０・・・電磁波処理部
　４１・・・塗布部
　４３・・・電磁波照射部
　４４・・・チャンバ
　４７・・・不凍液層
　６０・・・色素増感型太陽電池
　６１・・・透明基板
　６２・・・透明導電層
　６３・・・半導体電極層
　６４・・・電解質層
　６５・・・対向電極
　６６・・・対向基板
　６７・・・封止材
　８１・・・透明酸化物半導体層
　８６・・・基材フィルム DESCRIPTION OF SYMBOLS 1 ... Semiconductor electrode layer 2, 3 ... Metal oxide semiconductor fine particle 2A ... 1st granular fine particle 2B ... 2nd granular fine particle 4 ... 1st oxide layer 5 ... 1st 2 oxide layer 6 ... support 7 ... adhesion auxiliary layer 16 ... film substrate 21 ... semiconductor electrode layer 31 ... roll 32 ... firing furnace 33 ... metal oxide semiconductor Porous layer 34 ... Back roll 35 ... Press roll 36 ... Cooling roll 37 ... Winding roll 40 ... Electromagnetic wave processing part 41 ... Application part 43 ... Electromagnetic wave irradiation part 44 .... Chamber 47 ... Antifreeze layer 60 ... Dye-sensitized solar cell 61 ... Transparent substrate 62 ... Transparent conductive layer 63 ... Semiconductor electrode layer 64 ... Electrolyte layer 65 ... Opposite Electrode 66 ... Counter substrate 67 ... Sealing material 81 ... Transparent acid Things semiconductor layer 86 ... substrate film

Claims (17)

  1. 　支持体に形成された酸化物半導体層を電磁波照射により加熱すると共に、上記支持体を冷却する工程を含む酸化物半導体層の製造方法。 The manufacturing method of the oxide semiconductor layer including the process of heating the oxide semiconductor layer formed in the support body by electromagnetic wave irradiation, and cooling the said support body.
  2. 　上記支持体は、樹脂フィルム基材を含む請求項１に記載の酸化物半導体層の製造方法。 The method for producing an oxide semiconductor layer according to claim 1, wherein the support includes a resin film substrate.
  3. 　上記酸化物半導体層は、支持体の一主面上に形成され、
    　上記支持体の他の主面に冷却部材を密着させることにより、上記支持体を冷却する請求項１に記載の酸化物半導体層の製造方法。     The oxide semiconductor layer is formed on one main surface of the support,
    The manufacturing method of the oxide semiconductor layer of Claim 1 which cools the said support body by closely_contact | adhering a cooling member to the other main surface of the said support body.
  4. 　上記支持体と上記冷却部材との間に冷却媒層が設けられ、
    　上記支持体と上記支持体の他の主面が上記冷却媒層を介して密着された請求項３に記載の酸化物半導体層の製造方法。     A cooling medium layer is provided between the support and the cooling member;
    The method for producing an oxide semiconductor layer according to claim 3, wherein the support and the other main surface of the support are in close contact with each other via the cooling medium layer.
  5. 　上記冷却媒層は、不凍液である請求項４に記載の酸化物半導体層の製造方法。 The method for producing an oxide semiconductor layer according to claim 4, wherein the cooling medium layer is an antifreeze solution.
  6. 　上記電磁波照射による加熱温度は、上記樹脂フィルム基材の耐熱温度以上である請求項２に記載の酸化物半導体層の製造方法。 The method for producing an oxide semiconductor layer according to claim 2, wherein the heating temperature by the electromagnetic wave irradiation is equal to or higher than a heat resistant temperature of the resin film substrate.
  7. 　上記支持体は、透明導電層が形成された樹脂フィルム基材である請求項１に記載の酸化物半導体層の製造方法。 The method for producing an oxide semiconductor layer according to claim 1, wherein the support is a resin film substrate on which a transparent conductive layer is formed.
  8. 　上記透明導電層は、ＩＴＯであり、上記電磁波照射を、酸素を含まない雰囲気で行う請求項７に記載の酸化物半導体層の製造方法。 The method for producing an oxide semiconductor layer according to claim 7, wherein the transparent conductive layer is made of ITO, and the electromagnetic wave irradiation is performed in an atmosphere not containing oxygen.
  9. 　上記電磁波照射の前に、上記支持体に形成された酸化物半導体層に対して、焼成処理を行う工程をさらに備える請求項１に記載の酸化物半導体層の製造方法。 The method for producing an oxide semiconductor layer according to claim 1, further comprising a step of firing the oxide semiconductor layer formed on the support before the electromagnetic wave irradiation.
  10. 　支持体に形成された酸化物半導体層に対して、加圧処理を行う工程をさらに備える請求項１に記載の酸化物半導体層の製造方法。 The manufacturing method of the oxide semiconductor layer of Claim 1 further equipped with the process of performing a pressurization process with respect to the oxide semiconductor layer formed in the support body.
  11. 　上記加圧処理を、上記電磁波照射の前および後、または前若しくは後に行う請求項１０に記載の酸化物半導体層の製造方法。 The method for producing an oxide semiconductor layer according to claim 10, wherein the pressure treatment is performed before and after, or before or after the electromagnetic wave irradiation.
  12. 　上記酸化物半導体層は、色素増感型太陽電池に用いる、酸化チタン、酸化亜鉛、酸化タングステン、酸化ニオブ、チタン酸ストロンチウムおよび酸化スズからなる群から選ばれた少なくとも１種の酸化物半導体微粒子を含む酸化物半導体微粒子層である請求項１に記載の酸化物半導体層の製造方法。 The oxide semiconductor layer includes at least one oxide semiconductor fine particle selected from the group consisting of titanium oxide, zinc oxide, tungsten oxide, niobium oxide, strontium titanate, and tin oxide, which is used in a dye-sensitized solar cell. The method for producing an oxide semiconductor layer according to claim 1, wherein the oxide semiconductor layer comprises an oxide semiconductor fine particle layer.
  13. 　上記加圧処理は、カレンダー処理である請求項１０に記載の酸化物半導体層の製造方法。 The method for manufacturing an oxide semiconductor layer according to claim 10, wherein the pressure treatment is a calendar treatment.
  14. 　上記酸化物半導体層は、透明酸化物半導体層である請求項１に記載の酸化物半導体層の製造方法。 The method for producing an oxide semiconductor layer according to claim 1, wherein the oxide semiconductor layer is a transparent oxide semiconductor layer.
  15. 　上記透明酸化物半導体層は、ＩＴＯを含む請求項１４に記載の酸化物半導体層の製造方法。 The method for producing an oxide semiconductor layer according to claim 14, wherein the transparent oxide semiconductor layer contains ITO.
  16. 　上記電磁波照射を、酸素を含まない雰囲気で行う請求項１５に記載の酸化物半導体層の製造方法。 The method for manufacturing an oxide semiconductor layer according to claim 15, wherein the electromagnetic wave irradiation is performed in an atmosphere not containing oxygen.
  17. 　ロールツーロールプロセスにおいて上記工程が行われる請求項１に記載の酸化物半導体層の製造方法。 The method for producing an oxide semiconductor layer according to claim 1, wherein the step is performed in a roll-to-roll process.
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