JP2007179854A - Manufacturing method of metal oxide semiconductor electrode for photoelectric conversion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing process in which a porous metal oxide semiconductor layer having a high conversion efficiency can be formed by a treatment of a short time and by using a resin base material, and furthermore to enable manufacturing of an electrode for photoelectric conversion and a photoelectric conversion cell using the metal oxide semiconductor layer. <P>SOLUTION: This is the manufacturing method of the metal oxide semiconductor electrode for photoelectric conversion including a transparent base material equipped with a transparent conductive layer and the metal oxide semiconductor porous material layer, and this is the manufacturing method of the metal oxide semiconductor electrode for photoelectric conversion including a process in which metal oxide semiconductor particles of the average primary particle diameter of 5 nm or more and 500 nm or less are film-formed on the transparent conductive layer so that it is formed into the metal oxide semiconductor porous layer, and a process in which, under a gas atmosphere or a reduced pressure state, an excimer lamp treatment is applied on the metal oxide semiconductor porous layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a production process for producing a metal oxide semiconductor electrode having a metal oxide porous shape, a photoelectric conversion electrode using the metal oxide semiconductor electrode, and a photoelectric conversion cell.

  For solar power generation, single crystal silicon solar cells, polycrystalline silicon solar cells, amorphous silicon solar cells, and compound solar cells such as cadmium telluride and indium copper selenide have been put into practical use or are subject to research and development. It is necessary to overcome problems such as manufacturing cost, securing raw materials, and long energy payback time. On the other hand, many solar cells using organic materials aimed at increasing the area and cost have been proposed, but there is a problem that conversion efficiency is low and durability is poor.

Under such circumstances, a photoelectric conversion electrode and a photoelectric conversion cell using a metal oxide semiconductor porous material sensitized with a dye, and a material and a manufacturing technique for producing the electrode have been disclosed (Non-Patent Document 1). And Patent Document 1). The proposed battery is a dye-sensitized photoelectric conversion cell comprising a titanium oxide porous layer spectrally sensitized with a sensitizing dye such as a ruthenium complex, an electrolyte mainly composed of iodine, and a counter electrode. The first advantage of this method is that an inexpensive oxide semiconductor such as titanium oxide is used, so that an inexpensive photoelectric conversion element can be provided. The second advantage is that the ruthenium complex used has a wide absorption in the visible light range. Therefore, a relatively high conversion efficiency can be obtained.
In the present specification, the term “porous” widely refers to an aggregate of particles, or a film formation state having a high surface area such as a state in which they are connected while maintaining a high surface area via a necking portion. When there is no necking and it is desired to discuss the film formation state as an aggregate of particles, it may be referred to as a particle layer, particle body, particle, or the like.

  In addition, a cell was produced using an electrode in which a ruthenium complex having a tripyridylcarboxylate ligand was adsorbed on a titanium oxide porous layer formed by baking after film formation with a titanium oxide paste, and a conversion efficiency of 10.4. % Has been reported (see Non-Patent Document 2).

  One of the problems in manufacturing such a dye-sensitized photoelectric conversion cell is that it requires a high-temperature sintering process. A commonly used technique for forming a titanium oxide porous layer is to cause necking between particles by applying a temperature of 400 ° C. or higher to the titanium oxide particle layer formed by applying a dispersion paste of titanium oxide particles. This makes it porous and improves the electron transferability. For this reason, since the base material which can be used is restricted to the material with high heat resistance like glass, the manufacturing cost of the base material cost of a photoelectric conversion cell, the energy cost consumed at the time of manufacture, etc. is made expensive. Attempts have also been made to make a porous titanium oxide layer by applying a temperature at which the resin does not dissolve, but the conversion efficiency is low. Furthermore, the titanium oxide porous layer prepared by low-temperature firing was brittle and the cell durability was low (see Non-Patent Document 3). The sintering method for firing at a low temperature also has a relatively long sintering time, and from this point, there is a problem as a mass production process.

As a method for producing a metal oxide porous layer using a resin as a base material, there is a method in which a metal oxide particle layer is pressurized (see Non-Patent Document 4 and Patent Document 2). However, in the case of pressure treatment alone, since the pressure used is as high as several hundred kgf / cm ² , a high-pressure hydraulic device is required, and in a continuous production device such as a roll-to-roll, a roll that transmits pressure is worn, This method is not suitable for continuous production because it is easy to break and processing speed is slow.
Nature (Vol.353, 737-740, 1991) US Patent 4927721 J. Am. Chem. Soc. (2001), Vol. 123, pp1613-1624 ECN contributions 16th European Photovoltaic Solar Enargy Conference and Exhibition, May 1-5,2000 abstract; PMSommeling et.al, “Flexible dye-sensitized nanocristallineTiO2 solar cells” Nanoletters, 1, (2001), pp97-100, H. Lindstron, et.al. WO-0072373 pamphlet

  To enable an inexpensive process for a dye-sensitized photoelectric conversion cell, a porous metal oxide semiconductor that can be processed in a short time and has a high conversion efficiency using an inexpensive resin base material There has been a demand for layer forming technology.

  An object of the present invention is to provide a manufacturing process capable of forming a porous metal oxide semiconductor layer having a high conversion efficiency by using a resin base material in a short time, and consequently, the metal oxidation. It is also possible to manufacture a photoelectric conversion electrode and a photoelectric conversion cell using a physical semiconductor layer.

  The inventors have found that the above problems can be solved by using an excimer lamp treatment method, and have reached the present invention.

（式中、Ｍは、１価から6価の金属原子を示す。Ａ、Ｂは、それぞれ独立に酸素、窒素、リン、イオウ原子を示し、Ｘは２価の有機残基を示す。矢印はＡおよびＢからＭへの配位結合またはイオン結合を示す。）
さらに、式（１）の部分構造が、下記式（２）の部分構造である請求項６記載の光電変換用金属酸化物半導体電極の製造方法。
式（２）

（式中、Ｍは、１価から6価の金属原子を示す。Ｒ₁, Ｒ₂, Ｒ₃は、それぞれ独立に水素原子又は１価の置換基を示す。矢印は、酸素原子からＭへの配位結合またはイオン結合を示す。破線は、ジケトナート化合物構造中の非局在結合を示す。）
また、金属酸化物半導体粒子が、酸化チタン、酸化亜鉛、酸化スズおよび酸化ニオブの群から選ばれる少なくとも１種の化合物を含む上記製造方法が好ましい。 The present invention relates to a method for producing a metal oxide semiconductor electrode for photoelectric conversion comprising a transparent substrate provided with a transparent conductive layer and a metal oxide semiconductor porous layer, wherein the metal oxide has an average primary particle size of 5 nm to 500 nm. A step (1) of forming a semiconductor oxide particle on a transparent conductive layer to form a metal oxide semiconductor porous layer, and a step of subjecting the metal oxide semiconductor porous layer to an excimer lamp treatment in a gas atmosphere or under reduced pressure ( 2) and a method for producing a metal oxide semiconductor electrode for photoelectric conversion.
In addition, the production method described above, wherein the step (2) is performed using a dielectric barrier discharge excimer lamp, is preferable. The above-mentioned production method is characterized in that the step (2) is performed using a light source that emits light with a maximum wavelength of 172 nm and a half-value width of 30 nm or less, a maximum wavelength of 222 nm and a half-value width of 20 nm or less, or a maximum wavelength of 146 nm and a half-value width of 30 nm or less. Is preferred. In addition, the above production method is preferable, wherein the step (2) is performed with an irradiation intensity of 0.1 mW / cm 2 or more and 1000 mW / cm 2 or less. Moreover, the said manufacturing method characterized by performing a process (2), keeping a to-be-processed object at 250 degrees C or less is preferable. Also, the metal oxide semiconductor porous layer is obtained from a treated metal oxide semiconductor particle dispersion obtained by bringing a metal oxide semiconductor particle into contact with a metal atom complex containing a partial structure of the following formula (1) The production method described above is preferable.
Formula (1)

(In the formula, M represents a monovalent to hexavalent metal atom. A and B independently represent oxygen, nitrogen, phosphorus and sulfur atoms, and X represents a divalent organic residue. Coordination bond or ionic bond from A and B to M is shown.)
Furthermore, the manufacturing method of the metal oxide semiconductor electrode for photoelectric conversion of Claim 6 whose partial structure of Formula (1) is a partial structure of following formula (2).
Formula (2)

(In the formula, M represents a monovalent to hexavalent metal atom. R ₁ , R ₂ , and R ₃ each independently represent a hydrogen atom or a monovalent substituent. The arrow represents an oxygen atom to M. (The broken line indicates a delocalized bond in the structure of the diketonate compound.)
Moreover, the said manufacturing method in which a metal oxide semiconductor particle contains the at least 1 sort (s) of compound chosen from the group of a titanium oxide, a zinc oxide, a tin oxide, and niobium oxide is preferable.

  Next, this invention relates to the semiconductor cell for photoelectric conversion provided with the metal oxide semiconductor electrode for photoelectric conversion, the sensitizing dye layer, the electrolyte layer, and the electroconductive counter electrode which can be obtained by said manufacturing method.

  In the present invention, a metal oxide semiconductor that can obtain a high conversion efficiency by forming a metal oxide semiconductor porous layer by performing an excimer lamp treatment on the transparent conductive layer on which the metal oxide semiconductor particle layer of the transparent electrode is formed An electrode could be created. Since the processing time can be greatly reduced as compared with the external heat treatment using an electric furnace or the like, continuous processing without batch processing is possible. Furthermore, the cost can be significantly reduced by using a resin base material as the base material. By using this manufacturing method, it became possible to mass-produce cells at low cost.

  The method for producing a metal oxide semiconductor electrode for photoelectric conversion of the present invention is a step of forming a metal oxide semiconductor porous layer by depositing metal oxide semiconductor particles having an average primary particle diameter of 5 nm or more and 500 nm or less on a transparent conductive layer. (1) and a step (2) of subjecting the metal oxide semiconductor porous layer to an excimer lamp treatment in a gas atmosphere or under reduced pressure.

(Metal oxide semiconductor porous layer forming method by excimer lamp treatment method, step 2)
In the present invention, a metal oxide semiconductor particle layer and a transparent conductive layer comprising metal oxide semiconductor particles having an average primary particle diameter of 5 nm or more and 500 nm or less formed by a coating method on a transparent conductive layer of a transparent electrode that is an object to be processed Metal oxide for photoelectric conversion by forming necking between metal oxide semiconductor particles forming a metal oxide semiconductor porous layer by a process of excimer lamp treatment to the metal oxide semiconductor porous layer in a gas atmosphere or under reduced pressure A semiconductor electrode can be manufactured.

The dielectric barrier discharge excimer lamp uses light emission of discharge plasma generated when an alternating high voltage is applied between two electrodes provided on the outer wall surface of a quartz glass tube filled with a discharge gas. . The quartz glass tube has an inner cylinder part and an outer cylinder part. A discharge gas is contained between the inner cylinder and the outer cylinder, and a discharge electrode is formed on the quartz glass wall so that a voltage is generated between the inner cylinder and the outer cylinder. Has been placed. Since the electrode shape on the wall surface of the outer cylinder is not a plane structure but a network structure, local discharge can be generated uniformly over the entire tube. The plasma light generated by a dielectric barrier discharge excimer lamp emits light at a specific wavelength in the region corresponding to the far ultraviolet region to the vacuum ultraviolet region, and the half-value width is an emission line spectrum of about several nanometers centering on the maximum wavelength. It is possible to aim and shoot effects corresponding to. Since this excimer lamp can arrange the tubes in a plane, it is suitable for uniformly applying the effect of light of a specific wavelength to a planar irradiation object, unlike general laser light processing. The wavelength of the generated plasma light depends on the kind of filled discharge gas. For example, when the discharge gas is Xe ₂ , the maximum wavelength is 172 nm, when KrCl is 222 nm, and when Kr ₂ is 146 nm.

  The light energy of the light of the 172 nm dielectric barrier discharge excimer lamp is 166 to 167 Kcal / mol (195 to 6 Kcal / mol for the 146 nm lamp, 128 to 9 Kcal / mol for the 222 nm lamp). This energy is close to the interatomic bond energy (50 to 200 Kcal / mol) of an organic substance that exists stably at room temperature. In particular, it is close to the binding energy of double bonds such as C═C bond (140.5 Kcal / mol) and C═O bond (190.0 Kcal / mol). Since the compounds of formula (1) and formula (2), especially formula (2), have a structure containing these double bonds at a site coordinated to a metal atom in the molecular structure, light energy acts effectively. It can be seen that the effect of decomposing organic components to inorganic metal oxides is great.

  Furthermore, the compounds of the formulas (1) and (2) are easily bound to the surface of the inorganic metal oxide semiconductor particles, and act as a good dispersant in the solvent agent. Since a dispersion having good dispersibility can be formed, the film density is high when a film is formed using this dispersion. That is, a porous film in which particles are in close contact with each other can be formed by this dispersion, so that direct bond between particles can be quickly formed during the decomposition of organic matter by excimer lamp treatment. This effect is more conspicuous when a solvent having a water content of 10% by weight or less is used as the solvent because hydrolysis does not occur in the solvent and a stable dispersion state can be formed. Furthermore, it is preferable to use an alcohol solvent as the solvent. When the organic matter is decomposed by the excimer lamp treatment, the compounds of the formulas (1) and (2) leave a metal oxide, which contributes to the formation of a new binding site (necking formation) at the contact site between the particles. It contributes to providing a solar cell with high conversion efficiency as a dye-sensitized solar cell.

  The organic substance is decomposed and removed by the excimer lamp treatment by comparing the treated titanium oxide electrode with the titanium oxide powder scraped from the untreated titanium oxide electrode by thermal analysis (TGA). It can be observed as a difference in the remaining amount of organic matter adhering to titanium.

  When manufacturing a metal oxide semiconductor electrode for photoelectric conversion using a resin film as a base material, performing an excimer lamp treatment while heating it within a range where the base material does not change has the effect of decomposing and removing organic matter. The conversion efficiency when forming a dye-sensitized solar cell is large, and hence is preferable. The heating in a range where the base material does not change is, for example, up to about 170 ° C. when PET is used as the base material, and up to about 200 ° C. in the case of PEN. Heating beyond this will cause problems in production, for example, causing deformation of the substrate.

  As a method for performing excimer lamp processing on an object to be processed, a method in which a sheet-like object to be processed moves continuously with respect to an excimer lamp processing apparatus and is accompanied by a winding operation is useful as a method for manufacturing at low cost. It is. At this time, it is also possible to obtain a continuous heating effect by devising to continuously change the positional relationship while the object to be processed is kept in close contact with the heating body.

  In the present invention, before and after the excimer lamp treatment, pretreatment of the object to be treated with a solvent containing water, a tasteless oxide precursor containing tetraisopropyl orthotitanate, and an organic or inorganic treatment agent, Processing may be performed.

(Metal oxide semiconductor particle layer, step 1)
The material of the metal oxide semiconductor particle layer having an average particle diameter of 5 nm to 500 nm used in the present invention is titanium oxide, tin oxide, tungsten oxide, zinc oxide, indium oxide, niobium oxide, iron oxide, nickel oxide, cobalt oxide, Examples include strontium oxide, tantalum oxide, antimony oxide, lanthanoid oxide, yttrium oxide, vanadium oxide, etc., but after these excimer lamp treatment, a metal oxide semiconductor porous layer is formed and electrons in a photoexcited state The present invention is not limited to this as long as it has electrical conductivity and can be converted into visible light and / or near-infrared light by connecting a sensitizing dye. The material of the metal oxide semiconductor particles may be a combination of a plurality of types of metal oxides. In order for the surface of the metal oxide semiconductor porous layer to be sensitized by the sensitizing dye, it is desirable that the conduction band of the metal oxide semiconductor porous layer is present at a position where electrons can be easily received from the photoexcitation order of the sensitizing dye. For this reason, titanium oxide, tin oxide, zinc oxide, niobium oxide and the like are particularly used among the metal oxide semiconductor particles. Further, titanium oxide is particularly used from the viewpoint of price and environmental hygiene. In the present invention, one or more kinds of metal oxide semiconductor particles having an average particle diameter of 5 nm to 500 nm can be selected and combined.

  The metal oxide semiconductor particle layer is formed, for example, by preparing a paste in which metal oxide semiconductor particles are dispersed in a solvent, applying the paste to the surface of the transparent electrode, and evaporating the solvent. When preparing the paste, if necessary, an acid such as nitric acid or acetylacetone, a dispersant such as polyethylene glycol or Triton X-100, or an organic substance may be mixed with the paste component, but a small amount is preferably used. Monodispersed colloidal particles obtained from hydrothermal synthesis may be used. As a method for forming a metal oxide semiconductor particle layer, a coating method is simple and desirable as a method having mass productivity. A coating method using a spin coater, a coating method using screen printing, a coating method using a squeegee, a dipping method, a spraying method, a transfer method, a roller method, or the like can be used. After film formation, it is desirable to remove volatile components by drying at a temperature that does not alter the substrate. Furthermore, when the transparent substrate is a resin substrate, pre-baking treatment may be performed at a temperature of about 150 ° C. at which the transparent substrate does not change. A spraying film-forming method that does not use a solvent, such as an aerosol method disclosed in JP-A-2002-184477, and a method that uses energy application such as heating at the time of spraying may be used. Further, the metal oxide semiconductor particle layer may be formed by electrodeposition of metal oxide semiconductor particles.

  After deposition of the metal oxide semiconductor particle layer, before or after excimer lamp treatment of the object to be treated, pressurization, light treatment, applied voltage treatment, plasma atmosphere treatment, chemical treatment, ultrasonic treatment, Other treatment methods such as ultrasonic welding treatment, microwave irradiation treatment, electron beam treatment, and ozone treatment can be used in combination. Before and after excimer lamp treatment, pre-treatment and post-treatment of water-containing solvents, tasteless oxide precursors such as tetraisopropyl orthotitanate, and organic and inorganic treatment agents May be performed.

(Transparent conductive layer)
The transparent conductive layer used is not particularly limited as long as it is a conductive material that absorbs little light from the visible to the near infrared region of sunlight, but ITO (indium-tin oxide) or tin oxide (fluorine or the like is doped) A metal oxide having good conductivity, such as zinc oxide, or carbon is preferable. In the present invention, another layer may be added for the purpose of promoting the binding between the transparent electrode layer and the metal oxide particle layer, improving the electron transfer, or preventing the reverse electron process. .

(Transparent substrate)
The transparent substrate to be used is not particularly limited as long as it is a material that absorbs less light in the visible to near infrared region of sunlight. Glass substrates such as quartz, ordinary glass, BK7, lead glass, polyethylene terephthalate, polyethylene naphthalate, polyimide, polyester, polyethylene, polycarbonate, polyvinyl butyrate, polypropylene, tetraacetylcellulose, syndioctane polystyrene, polyphenylene sulfide, polyarylate Resin base materials such as polysulfone, polyester sulfone, polyetherimide, cyclic polyolefin, brominated phenoxy, and vinyl chloride can be used.

  In the present invention, an inorganic porous metal oxide semiconductor electrode obtained by excimer lamp treatment is immersed in a solution in which a sensitizing dye is dissolved together with a transparent substrate, thereby connecting the inorganic porous surface and the sensitizing dye. A method of contacting and binding a sensitizing dye to an inorganic porous surface using the affinity of a substituent is common, but is not limited to this method.

  The solvent for preparing the sensitizing dye solution needs to be a solvent that can dissolve the sensitizing dye and mediate dye adsorption on the metal oxide layer. In order to dissolve the sensitizing dye, heating, addition of a solubilizing agent, and filtration of insoluble matter may be performed as necessary. Two or more kinds of solvents may be used as a mixture, and alcohol solvents such as ethanol, isopropyl alcohol, and benzyl alcohol, nitrile solvents such as acetonitrile and propionitrile, and halogens such as chloroform, dichloromethane, and chlorobenzene. Solvents, ether solvents such as diethyl ether and tetrahydrofuran, ester solvents such as ethyl acetate and succinbutyl, ketone solvents such as acetone, methyl ethyl ketone and cyclohexanone, carbonate solvents such as diethyl carbonate and propylene carbonate, hexane and octane Carbohydrate solvents such as toluene, xylene, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, 1,3-dimethylimidazolinone, N-methylpyrrolidone, water, etc. Yes, but not limited to this. Two or more kinds of solvents may be mixed and used.

  The film thickness of the metal oxide semiconductor porous layer formed on the conductive surface of the transparent substrate is desirably 0.5 μm or more and 200 μm or less. When the film thickness is less than this range, effective conversion efficiency cannot be obtained. If the film thickness is thicker than this range, it may be difficult to create such as cracking or peeling during film formation. On the other hand, the distance between the metal oxide porous body surface and the conductive surface increases, so the generated charge is effectively applied to the conductive surface. Since it cannot be transmitted, it becomes difficult to obtain good conversion efficiency.

(Description of sensitizing dye for photoelectric conversion)
As a sensitizing dye for photoelectric conversion used in the present invention, a ruthenium complex dye having a structure represented by the following formula (3) is representative. This includes Ruthenium 535 and Ruthenium 535-bisTBA manufactured by SOLARONIX.

Formula (3)

  Further, as sensitizing dyes for photoelectric conversion, azo dyes, quinacridone dyes, diketopyrrolopyrrole dyes, squarylium dyes cyanine dyes, merocyanine dyes, triphenylmethane dyes, xanthene dyes, porphine dyes, Examples include chlorophyll dyes, ruthenium complex dyes, indigo dyes, perylene dyes, oxazine dyes, anthraquinone dyes, phthalocyanine dyes, naphthalocyanine dyes, and their derivatives, but they absorb light and are metal oxide semiconductors. The present invention is not limited to these as long as the dye can inject excited electrons into the conduction band of the electrode. When these sensitizing dyes have one or more linking groups in their structure, they can be connected to the surface of the inorganic semiconductor porous body, and the excited electrons of the photoexcited dye are transferred to the conduction band of the inorganic semiconductor porous body. This is desirable because it can be communicated quickly.

(Photoelectric conversion cell)
The photoelectric conversion electrode used in the present invention forms a photoelectric conversion cell by combining a conductive counter electrode through an electrolyte layer.

(Electrolyte layer)
The electrolyte layer used in the present invention is preferably composed of an electrolyte, a medium, and an additive. The electrolyte of the present invention is a mixture of I ₂ and iodide (for example, LiI, NaI, KI, CsI, MgI ₂ , CaI ₂ , CuI, tetraalkylammonium iodide, pyridinium iodide, imidazolium iodide, etc.), Br ₂ Mixtures of bromide and bromide (for example, LiBr, etc.), molten salts described in Inorg. Chem. 1996, 35, 1168-1178, etc. can be used, but not limited thereto. Among these, an electrolyte in which LiI, pyridinium iodide, imidazolium iodide, or the like is mixed as a combination of I ₂ and iodide is preferable in the present invention, but is not limited to this combination.
The preferable electrolyte concentration is 0.01 M to 0.5 M in the medium I ₂ and 0.1 M to 15 M in the iodide mixture.
The medium used for the electrolyte layer in the present invention is desirably a compound that can exhibit good ionic conductivity. Solution media include ether compounds such as dioxane and diethyl ether, chain ethers such as ethylene glycol dialkyl ether, propylene glycol dialkyl ether, polyethylene glycol dialkyl ether, and polypropylene glycol dialkyl ether, methanol, ethanol, and ethylene glycol monoalkyl. Alcohols such as ether, propylene glycol monoalkyl ether, polyethylene glycol monoalkyl ether, polypropylene glycol monoalkyl ether, polyhydric alcohols such as ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, glycerin, acetonitrile, glutarodinitrile, Methoxyacetonitrile, propioni Lil, nitrile compounds such as benzonitrile, ethylene carbonate, carbonate compounds such as propylene carbonate, heterocyclic compounds such as 3-methyl-2-oxazolidinone, dimethyl sulfoxide, aprotic polar substances such as sulfolane may be employed.

  In addition, a polymer can be included for the purpose of using a solid (including gel) medium. In this case, a polymer such as polyacrylonitrile or polyvinylidene fluoride is added to the solution-like medium, or a polyfunctional monomer having an ethylenically unsaturated group is polymerized in the solution-like medium to make the medium solid. To do.

  As the electrolyte layer, an electrolyte that does not require a CuI or CuSCN medium, and 2,2 ′, 7,7′-tetrakis (N, N—) described in Nature, Vol. 395, 8 Oct. 1998, p583-585. Hole transport materials such as di-p-methoxyphenylamine) 9,9'-spirobifluorene can be used.

  The electrolyte layer used in the present invention may contain an additive that functions to improve the electrical output of the photoelectric conversion cell or improve the durability. Examples of additives that improve electrical output include 4-t-butylpyridine, 2-picoline, and 2,6-lutidine. MgI etc. are mentioned as an additive which improves durability.

(Conductive counter electrode)
The conductive counter electrode used in the present invention functions as a positive electrode of the photoelectric conversion cell. Specific examples of conductive materials used for the counter electrode include metals (for example, platinum, gold, silver, copper, aluminum, rhodium, indium, etc.), metal oxides (ITO (indium-tin oxide), tin oxide (fluorine, etc.)). Including doped substances), zinc oxide), or carbon. The thickness of the counter electrode is not particularly limited, but is preferably 5 nm or more and 10 μm or less.

(How to assemble)
A photoelectric conversion cell is formed by combining the photoelectric conversion electrode and a conductive counter electrode through an electrolyte layer. In order to prevent leakage and volatilization of the electrolyte layer as necessary, sealing is performed around the photoelectric conversion cell. For sealing, a thermoplastic resin, a photocurable resin, glass frit, or the like can be used as a sealing material. The photoelectric conversion cell is made by connecting small-area photoelectric conversion cells as necessary. The electromotive voltage can be increased by combining the photoelectric conversion cells in series.

Examples will be specifically shown below, but the present invention is not limited to the following examples.
In particular, since the energy intensity condition, the pulse width condition, and the like remain in a range that can be changed by the testing machine, the present invention falls within the scope of the present invention if the excimer lamp effect can be obtained essentially under conditions other than the test range of the examples.
(Example 1)
-Transparent electrode As a transparent electrode of a resin base material having a conductive layer, a PET base transparent electrode or a PEN base transparent electrode (ITO transparent conductive layer) manufactured by Oji Tobi Co., Ltd. (surface resistance value 20Ω / □) was used.
-Adjustment of titanium oxide particle layer For all of Examples and Comparative Examples 1 and 2, 12g of P25 manufactured by Nippon Aerosol Co. was used as titanium oxide, and a bead disperser was used together with 1.2g of titanium acetylacetonate in 20g of 1-hexanol. A dispersion was made. For Comparative Example 4, the same weight of titanium ethoxide (Ti (OEt) ₄ ) was used instead of titanium acetylacetonate.
The film was applied on a transparent electrode in a size of 5 mm × 5 mm square, and after film formation, prebaking was performed in an oven at 140 ° C. for 1 hour.
・ Excimer lamp treatment (creation of titanium oxide electrode)
Ushio Inc. excimer lamp irradiation device (UER type as the processing unit; 50 mW / cm ² Ratings of radiation intensity at 172nm lamp in the irradiation window surface, 222 nm lamp 25mW / cm ^2, 146nm lamp is unknown illumination intensity is several mW / using cm ² seems vicinity), the excimer lamp treatment under the conditions shown in Table 2 with respect to the titanium oxide particle layer, was used as a metal oxide semiconductor electrode.

-Adsorption of sensitizing dye Ruthenium535-bisTBA manufactured by SOLARONIX was used as a sensitizing dye, and the dye was adsorbed by dissolving in an ethanol solvent and immersing the dye solution titanium oxide electrode. The colored electrode surface was washed with ethanol and dried to obtain a photoelectric conversion electrode.
-Preparation of electrolyte solution The electrolyte solution was obtained by the following prescription.
Solvent: 3-methoxypropionitrile
LiI: 0.1M
I ₂ : 0.05M
4-t-butylpyridine: 0.5M
1-propyl-2,3-dimethylimidazolium iodide: 0.6M

-Assembly of photoelectric conversion cell The test sample of the photoelectric conversion cell was assembled as shown in FIG.
As the conductive counter electrode, a platinum layer laminated by a sputtering method on the conductive layer of the glass substrate with a fluorine-doped tin oxide layer was used.
As the resin film spacer, a 25 μm thick “High Milan” film made by Mitsui DuPont Polychemical Co., Ltd. was used.

・ Measurement method for conversion efficiency Combined with an Oriel solar simulator and an air mass filter, the light intensity is adjusted to 100 mW / cm ² with a light meter to obtain a light source for measurement. The IV curve characteristics were measured using a V curve tracer. The conversion efficiency η was calculated by the following equation (4) using Voc (open circuit voltage value), Isc (short circuit current value), and ff (fill factor value) obtained from the IV curve characteristic measurement.

Formula (4)

η (%) = Voc (V) × Isc (mA) × ff × 100
100 (mW / cm ² ) × metal oxide semiconductor porous layer area (cm ² )

(Examples 2 to 11)
The treatment was performed by changing the lamp wavelength, distance from the lamp irradiation window, irradiation time, substrate temperature at the start of irradiation, and atmosphere in Example 1. The cell creation method, evaluation method, and the like were performed in the same manner as in Example 1.

(Example 12)
A titanium oxide electrode was prepared in the same manner as in Example 3 except that the same weight of zirconium acetylacetonate was used instead of titanium acetylacetonate among the raw materials of the dispersion used in Example 3, and the conversion efficiency was measured. Went. The cell creation method, evaluation method, and the like were performed in the same manner as in Example 1.

(Example 13)
Preparation of a titanium oxide electrode in the same manner as in Example 3 except that the same weight of Ti (—OC ₂ H ₄ —) ₂ was used instead of titanium acetylacetonate among the raw materials of the dispersion used in Example 3. The conversion efficiency was measured. The cell creation method, evaluation method, and the like were performed in the same manner as in Example 1. Ti (—OC ₂ H ₄ —) ₂ is a residue obtained by using Ti (0Me) ₄ as a raw material, performing a reflux treatment in an ethylene glycol solvent, and then removing the solvent under reduced pressure.

(Example 14)
A titanium oxide electrode was prepared in the same manner as in Example 3 except that the same weight of indium acetylacetonate was used instead of titanium acetylacetonate among the raw materials of the dispersion used in Example 3, and the conversion efficiency was measured. Went. The cell creation method, evaluation method, and the like were performed in the same manner as in Example 1.

(Comparative Example 1)
A titanium oxide electrode was prepared in the same manner as in Example 3 except that the excimer lamp treatment performed in Example 3 was not performed, and the conversion efficiency was measured. The cell creation method, evaluation method, and the like were performed in the same manner as in Example 1.

(Comparative Examples 2-3)
A titanium oxide electrode was prepared in the same manner as in Example 3 except that a xenon lamp was used instead of the excimer lamp in Example 3, and the conversion efficiency was measured. The cell creation method, evaluation method, and the like were performed in the same manner as in Example 1.

(Comparative Example 4)
A titanium oxide electrode was prepared in the same manner as in Example 3 except that the same weight of titanium ethoxide (Ti (OEt) ₄ ) was used instead of titanium acetylacetonate among the raw materials of the dispersion used in Example 3. The conversion efficiency was measured. The cell creation method, evaluation method, and the like were performed in the same manner as in Example 1.

Table 1 shows conditions, conversion efficiency, and the like of Examples 1 to 14 and Comparative Examples 1 to 4.

(Example 15)
A titanium oxide electrode was prepared in the same manner as in Example 3 except that a titanium oxide layer having a weight (size) capable of withstanding thermal analysis (TGA) was prepared, and the titanium oxide layer was scraped to obtain a sample. ) This was compared with the scraped sample in the case where the excimer lamp treatment was not performed and the untreated titanium oxide powder, and a relative comparison of weight loss was performed. Those without the excimer lamp treatment showed a weight loss of 1.25% at 450 ° C. with respect to the untreated titanium oxide, while those without the excimer lamp treatment showed a weight loss of 0.05%. Almost no organic component remained. The TGA measurement conditions were an air atmosphere, a heating rate of 20 ° C./min.

Photoelectric conversion cell test sample.

Explanation of symbols

1: Titanium oxide porous layer (photosensitive sensitizing dye already adsorbed)
2: Electrolyte solution layer 3: Transparent conductive layer (ITO or FTO)
4: Pt electrode layer 5: PET substrate or glass substrate 6: Resin film spacer 7: Conversion efficiency measurement lead

Claims (9)

  A method for producing a metal oxide semiconductor electrode for photoelectric conversion comprising a transparent substrate provided with a transparent conductive layer and a metal oxide semiconductor porous layer, wherein metal oxide semiconductor particles having an average primary particle diameter of 5 nm to 500 nm A step (1) for forming a metal oxide semiconductor porous layer by forming a film on the transparent conductive layer, and a step (2) for performing an excimer lamp treatment on the metal oxide semiconductor porous layer in a gas atmosphere or under reduced pressure. A method for producing a metal oxide semiconductor electrode for photoelectric conversion, comprising:   2. The method for producing a metal oxide semiconductor electrode for photoelectric conversion according to claim 1, wherein the step (2) is performed using a dielectric barrier discharge excimer lamp.   The step (2) is performed using a light source that emits light at a maximum wavelength of 172 nm and a half-value width of 30 nm or less, a maximum wavelength of 222 nm and a half-value width of 20 nm or less, or a maximum wavelength of 146 nm and a half-value width of 30 nm or less. 2. A method for producing a metal oxide semiconductor electrode for photoelectric conversion according to 2.   The method for producing a metal oxide semiconductor electrode for photoelectric conversion according to any one of claims 1 to 3, wherein the step (2) is performed with an irradiation intensity of 0.1 mW / cm 2 or more and 1000 mW / cm 2 or less.   The method for producing a metal oxide semiconductor electrode for photoelectric conversion according to any one of claims 1 to 4, wherein the step (2) is performed while maintaining the object to be treated at 250 ° C or lower. The porous metal oxide semiconductor layer is obtained from a treated metal oxide semiconductor particle dispersion obtained by bringing a metal oxide semiconductor particle into contact with a metal atom complex containing a partial structure of the following formula (1). The manufacturing method of the metal oxide semiconductor electrode for photoelectric conversions of any one of Claims 1-5 characterized by the above-mentioned.
Formula (1)

(In the formula, M represents a monovalent to hexavalent metal atom. A and B independently represent oxygen, nitrogen, phosphorus and sulfur atoms, and X represents a divalent organic residue. Coordination bond or ionic bond from A and B to M is shown.) The method for producing a metal oxide semiconductor electrode for photoelectric conversion according to claim 6, wherein the partial structure of the formula (1) is a partial structure of the following formula (2).
Formula (2)

(In the formula, M represents a monovalent to hexavalent metal atom. R ₁ , R ₂ , and R ₃ each independently represent a hydrogen atom or a monovalent substituent. The arrow represents an oxygen atom to M. (The broken line indicates a delocalized bond in the structure of the diketonate compound.)   The metal oxide semiconductor electrode for photoelectric conversion according to any one of claims 1 to 7, wherein the metal oxide semiconductor particles contain at least one compound selected from the group consisting of titanium oxide, zinc oxide, tin oxide and niobium oxide. Manufacturing method. The semiconductor cell for photoelectric conversion provided with the metal oxide semiconductor electrode for photoelectric conversion, the sensitizing dye layer, the electrolyte layer, and the electroconductive counter electrode which can be obtained with the manufacturing method of any one of Claims 1-8.

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