JP2007263834A - Evaluation method of porous metal-metal oxide complex by image sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for evaluating quantitatively a porous titanium-titanium oxide complex used for a photocatalyst or a dye-sensitized solar cell. <P>SOLUTION: The porous titanium-titanium oxide complex is imaged by using an image sensor, and at least one of hue, chroma and lightness of each pixel in the imaged image is calculated, and a pixel wherein at least calculated one of hue, chroma and lightness is a prescribed value or within a prescribed range is extracted, and the porous titanium oxide portion is evaluated quantitatively based on the extracted pixel. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for evaluating a porous metal-metal oxide composite such as a porous titanium-titanium oxide composite, and more particularly to a porous metal-metal oxide composite used in a dye-sensitized solar cell. It relates to a method for evaluating the body.

  Titanium (Ti) is the metal that has the strongest corrosion resistance among practical metals, its specific gravity is small compared to steel, etc., and its specific strength is very good. It is widely used for plant plant materials and medical materials. ing. In recent years, due to its high corrosion resistance, its use in building materials such as roofing materials is rapidly progressing.

  In addition, titanium oxide (titania), which is an oxidized form of titanium, has excellent properties such as UV absorption and adsorption, so it can be used in pigments, paints, cosmetics, UV blocking materials, catalysts, catalyst carriers, Used for electronics materials. More recently, the photocatalytic and amphipathic effects that occur when titanium oxide absorbs ultraviolet rays have attracted attention, and have been confirmed to be harmful organic matter decomposition, air pollutant removal, sterilization, and self-cleaning effects. Various products using a titanium catalyst are commercially available.

  Furthermore, the application of titanium oxide to photoelectric conversion elements used in various sensors, copiers, photovoltaic devices and the like has been studied. For example, a dye-sensitized solar cell announced by Gretzell et al. In 1991 is a wet solar cell using a porous titanium oxide thin film spectrally sensitized with a ruthenium complex as a working electrode, and has performance similar to that of a silicon solar cell. It has been reported that it can be obtained (see Non-Patent Document 1). According to this technique, an inexpensive photoelectric semiconductor element such as titanium oxide is formed on a transparent electrode that is a support, and a film is formed. There is an advantage that an inexpensive photoelectric conversion element can be provided.

  Methods for forming a titanium oxide film such as titania on the surface of titanium or a titanium-based alloy include a thermal oxidation method, a chemical oxidation method, and an electrolytic oxidation method. In general, an electrolytic oxidation method having excellent properties and reproducibility is used.

  When titanium is electrolytically oxidized, a non-porous titanium oxide thin film of 1 μm or less is usually formed on the surface, and a beautiful interference color is formed on the surface. This technique is generally used for decorative purposes and is widely used industrially. On the other hand, it has also been reported that by selecting the type of electrolyte solution, a porous titanium oxide having an aspect ratio of 6 or more in the formed pores is generated (see Patent Document 1). For example, in Patent Document 1, by using a solution containing an ion containing a halogen atom as an electrolyte, a nanotube-shaped porous titanium oxide having an aspect ratio of 6 or more is generated on the surface of the titanium metal, and porous titanium-titanium. It is reported that an oxide complex is formed. This porous titanium-titanium oxide composite is very effective as a material for photocatalysts and photoelectric conversion elements, and in particular, as the porous titanium oxide is uniformly and densely formed, it exhibits better properties. It is highly expected as a technology.

  However, even when titanium is electrolytically oxidized using an electrolyte solution containing ions containing halogen atoms, a porous titanium-titanium oxide having a nanotube shape is not always formed uniformly and densely. Even if the electrolyte composition and electrolytic oxidation treatment conditions are the same, depending on the surface unevenness of the titanium metal used as the material, the porous titanium oxide may be uneven or, in extreme cases, the porous titanium oxide. May be formed in spots on the surface of titanium metal. Such a difference is more likely to occur as the area of the porous titanium-titanium oxide formed by electrolytic oxidation increases.

Until now, there was no method for quantitatively evaluating the uniformity and denseness of porous titanium oxide, so the actual situation was that the judgment was made by the manufacturer. In order to use porous metal-metal oxide composites such as porous titanium-titanium oxide composites as industrial materials such as photoelectric conversion element materials, quantitative evaluation methods for uniformity and denseness should be used. It is essential to develop and establish quality control methods.
JP 2005-263580 A Japanese Patent Publication No. 7-9401 JP 2002-131133 A By Oregan et al., “Nature”, 1991, Vol. 353, p. 737-739

  As described above, until now, there has been no method for quantitatively evaluating the uniformity and denseness of porous metal-metal oxide composites including porous titanium-titanium oxide composites. Of course, by observation with an electron microscope, the uniformity and density of the porous metal-metal oxide composite can be determined locally, but the large-area porous metal-metal used in solar cells and the like. It is not realistic to observe the entire surface of the oxide composite with an electron microscope. If the porous metal-metal oxide composite is applied to a dye-sensitized solar cell, the amount of dye attached when the sensitizing dye is attached to the surface of the porous metal-metal oxide composite Although it is not impossible to measure and evaluate whether the porous metal-metal oxide composite is suitable for a dye-sensitized solar cell, the amount of attached dye is quantified by a wet analysis method. Since it is necessary, there is a problem that it takes time and effort to evaluate. Moreover, in this method, in order to quantify the total amount of the dye attached to the porous metal-metal oxide composite as a sample, what happens to a specific place in the porous metal-metal oxide composite is determined. Cannot be evaluated.

  The present invention has been made in view of such a situation, and numerically represents the uniformity and denseness of porous metal-metal oxide composites including porous titanium-titanium oxide composites, The object is to provide a method for quantitative evaluation.

  The evaluation method of the present invention is an evaluation method for evaluating the surface state of a porous metal-metal oxide composite. In the evaluation method, an image sensor is used to image the porous metal-metal oxide composite, Calculating at least one of hue, saturation, and brightness of each pixel in the pixel, extracting a pixel in which at least one of the calculated hue, saturation, and brightness is within a predetermined range or a predetermined value, and extracting the extracted pixel Based on the above, the porous metal oxide portion is quantitatively evaluated.

  Here, pixels may be extracted based on the whiteness of the porous oxide portion, and the porous metal oxide portion may be quantitatively evaluated according to the number of extracted pixels.

  As a method for quantitative evaluation, specifically, there is a method based on the ratio between the number of extracted pixels and the total number of pixels corresponding to the porous metal-metal oxide composite in the captured image. .

  Another evaluation method of the present invention is an evaluation method for evaluating the surface state of a porous metal-metal oxide composite, wherein a dye is adsorbed to the porous metal-metal oxide composite, and the dye is used by using an image sensor. The porous metal-metal oxide composite after adsorption is imaged, and the degree of coloring is calculated for each pixel based on at least one of the hue, saturation, and brightness of each pixel in the imaged image. A pixel is extracted based on the above, and the porous metal oxide portion is quantitatively evaluated based on the extracted pixel.

  In the present invention, when evaluating a porous metal-metal oxide composite having a large area, the porous metal-metal oxide composite is scanned while the image sensor is scanned with respect to the porous metal-metal oxide composite. What is necessary is just to repeat and evaluate for every partial area | region of the surface of a composite_body | complex.

  In the present invention, the porous metal-metal oxide composite is obtained, for example, by subjecting a metal to electrolytic oxidation or anodization. A typical example of such a porous metal-metal oxide composite is a porous titanium-titanium oxide composite. In addition, for example, a porous zirconium-zirconium oxide composite, Examples thereof include hafnium-hafnium oxide.

  Hereinafter, the present invention will be described in detail.

  The image sensor used in the present invention includes, for example, a CCD (Charge Coupled Device) camera, converts an image of an object imaged by the CCD camera into a digital signal, and performs various arithmetic processes to thereby obtain an area of the object. , Features such as length, number, and position are extracted, and a determination result is output based on a set standard. The video output from the camera is an analog signal, but in order to apply it to various determinations and measurements, it must first be converted into a digital signal.

  If the video signal is a grayscale signal, the threshold value (binarization level) is set in the video signal, and the part that is higher (brighter) than the threshold value White and low (dark) portions can take either black values, and gray portions can be eliminated. This is called binarization. In the digital signal, white is “1 = HI” and black is “0 = LO”. In the present invention, if a pixel is extracted by performing threshold processing using only brightness, a binarization processing method can be used.

  In addition to the binarization method described above, there is a gray processing method for image processing. In the gray processing method, the shading of image data captured by a camera is handled as it is. In the binarization method, it can be recognized only as white, black, or 1 or 0 information, but in the gray processing method, the density is divided into, for example, 8 bits (= 256 gradations), and the result using all the information is obtained. . Therefore, the detection accuracy is greatly improved. In the present invention, if only the lightness of a pixel is calculated and pixels are extracted based on the lightness value or range, a gray processing method can be used.

  Further, there is a color processing method for obtaining a color video signal in a camera. A color video signal from the camera is converted into digital data of three primary colors of R (red), G (green), and B (blue) by an A / D (analog / digital) converter of an image input circuit. Difference processing is performed based on this data to obtain RG, BG, and RB data. From these six parameters R, G, B, RG, BG, and RB, the hue, saturation, and brightness of the pixel can be obtained. This conversion method is known, and is described in, for example, Patent Document 1 (Japanese Patent Publication No. 7-92401) or Patent Document 2 (Japanese Patent Laid-Open No. 2002-131133). After obtaining the hue, saturation, and lightness in this way, set the value or range for these to determine the degree of agreement with the specified color (or range of colors), that is, the specified hue, saturation, and lightness. In addition, color extraction can be performed. As a result, each image is binarized into extracted pixels and non-extracted pixels. With these processes, it is possible to achieve both an extraction capability that enables stable extraction even in dark colors and high-speed processing.

  In the present invention, when the surface state of the porous metal-metal oxide composite is evaluated, the porous metal-metal oxide composite is imaged using the above-described image sensor. Then, pixels that match the specified hue, saturation, and brightness are extracted from the captured image. In this case, pixels with specific values of hue, saturation, and brightness may be extracted strictly, or pixels within a certain range may be extracted. Further, instead of all of hue, saturation, and brightness, pixels may be extracted by comparing one or two of them. As a color designation method, a reference color is set, image processing is performed for the color, hue, saturation, and brightness are obtained, and the hue, saturation, and brightness of the designated color are obtained. The reference color is imaged for a reference sample that has been confirmed to be sufficiently dense and uniform by observation with an electron microscope, etc., and the hue, saturation, and brightness of each pixel are obtained. The hue, saturation, and lightness indicated by. As will be described later, the hue, saturation, and brightness of some color sample may be used. Therefore, the uniformity and denseness (Du) of the porous titanium oxide portion can be obtained from the following formula.

Du = P _n / P _s × 100 (%)
Here, P _n is the number of the extracted pixel per unit area of the sample, P _s is the number of the extracted pixel per unit area of the reference product.

  In particular, in the present invention, paying attention to the brightness in the image, based on this brightness, the whiteness of the porous titanium oxide portion of the porous titanium-titanium oxide composite, that is, the surface is obtained by anodizing the titanium plate. The degree of whiteness may be extracted, and the uniformity and denseness of the porous titanium oxide portion may be evaluated based on the pixel area of the extracted portion. In the porous titanium-titanium oxide composite, the more the titanium oxide portion is, the more white it looks visually. Therefore, the uniformity and denseness of the titanium oxide portion are referred to as whiteness. Therefore, the whiteness is the uniformity and fineness of the titanium oxide portion when using a sample in which the surface of the titanium plate is sufficiently anodized by anodizing the titanium plate at the stage of setting the reference color. It represents sex.

Whiteness = P _n / P _t × 100 (%)
Here, Pn is the number extraction of pixels per unit area of the sample, P _t is the number extraction of pixels per unit area of the sample surface a titanium plate was anodized becomes sufficiently uniformly white.

In the evaluation method of the present invention, when evaluating a large plate-like porous titanium-titanium oxide composite, for example, a large-scale (for example, 300 cm ² or more) porous titanium-titanium oxide produced industrially. When the composite is to be evaluated, the evaluation for each partial region on the surface of the porous metal-metal oxide composite may be repeatedly performed while scanning the image sensor. For example, the object to be evaluated is moved and measured for each area of 100 cm ² or for each area of an arbitrary area. By measuring in this way, the denseness and uniformity of the porous titanium oxide can be evaluated even when the object is enlarged.

  Next, the manufacturing method about the porous titanium-titanium oxide composite used as the evaluation object in an image sensor is demonstrated in detail.

  In the production of porous titanium-titanium oxide, titanium or an alloy containing titanium as a main component (hereinafter referred to as titanium alloy) is used as a raw material, and the material is prepared with oxygen, iron, nitrogen, hydrogen, etc. Pure titanium or a titanium alloy having a certain degree of press formability can be used. Specifically, as titanium or titanium alloy used as a raw material, JIS (Japanese Industrial Standard) 1, 2, 3, 4 kinds of various industrial pure titanium, nickel, ruthenium, tantalum, palladium, etc. Examples thereof include alloys added with improved corrosion resistance, alloys added with aluminum, vanadium, molybdenum, tin, iron, chromium, niobium, and the like. As the crystal type of titanium or titanium alloy, α-type, α + β-type, and β-type can be used regardless of single crystal or polycrystal. Regarding the shape, titanium or a titanium alloy itself may have various shapes such as a plate shape, a rod shape, and a mesh shape. In addition to these, titanium or titanium alloy may be formed on the surface of a different conductive material having a shape such as a plate, a rod, or a mesh. Those grown as a film of titanium alloy, those grown as a film of titanium or titanium alloy on the surface of a semiconductor or insulating material in the shape of a plate, rod, mesh, etc., but are not limited thereto is not.

  As these titanium or an alloy containing titanium as a main component, it is desirable to use one having a plurality of recesses on the surface, regardless of any of the above types. When electrolytic oxidation is performed using a solution containing an ion containing a halogen atom, first, a nanotube-shaped porous titanium oxide is generated in a concave portion. When electrolytic oxidation is continued, the porous titanium oxide gradually spreads on the surface starting from this part, and eventually the entire surface is covered densely and uniformly, and a good porous titanium-titanium oxide composite is formed. It is formed.

  The dimensions of these titanium or titanium-based alloys are not particularly limited. However, if porous titanium-titanium oxide is used as a photoelectric conversion element material such as a dye-sensitized solar cell. If the dimensions are too small, the cost of the manufacturing process is increased, and it is not a realistic material. If it has industrial practicality, it must be able to produce a porous titanium-titanium oxide of 3000 square centimeters or more. If it becomes this size, since the generation | occurrence | production nonuniformity of porous titanium oxide will be known clearly also by appearance, it will become still more important to measure a uniformity and a denseness quantitatively with an image sensor.

  Next, conditions for electrolytic oxidation (anodic oxidation) for forming a multi-titanium titanium-titanium oxide composite will be described.

  Electro-oxidation refers to a technology that forms porous titanium oxide on the surface of an anode by applying a voltage using titanium or a titanium alloy as an anode and any conductive material as a cathode in an electrolyte solution. It is sufficient that the state in which titanium or a titanium alloy is an anode is only once during processing. Therefore, the case where it implements, replacing an anode and a cathode alternately is also included.

In the electrolytic oxidation, the applied voltage is usually 5 to 200 V, preferably 10 to 150 V, more preferably 14 to 110 V, and the current density is 0.2 to 500 mA / cm ² , preferably 0.5 to 100 mA / cm. ^In the range of ² , the time is 1 minute to 24 hours, preferably 5 minutes to 10 hours. During the electrolysis, it is also possible to change the applied voltage and current density. In this case, electrolysis is performed by applying a pulse. Although it does not specifically limit as a period of a pulse, It is 0.001 Hz-1 MHz, Preferably it is 0.01 Hz-10000 Hz, More preferably, 0.1 Hz-1000 Hz is mentioned.

  Moreover, 0-50 degreeC is preferable and, as for the temperature of the electrolyte solution at the time of anodizing, More preferably, it is 0-40 degreeC.

  As an electrolytic solution used for electrolytic oxidation, when anodic polarization of titanium or a titanium alloy is required, a dissolving power capable of dissolving titanium or the titanium alloy is required. For this purpose, the electrolytic solution contains a halogen atom. It is important that ions to be included. The ion containing a halogen atom here is an ion containing any atom of fluorine, chlorine, bromine and iodine, specifically, fluoride ion, chloride ion, bromide ion, iodide ion, Perchlorate ion, chlorate ion, bromate ion, iodate ion, chlorite ion, bromite ion, hypochlorite ion, hypobromite ion, hypoiodite ion, etc. It is particularly preferred to use halide ions (fluoride ions, chloride ions, bromide ions, iodide ions). These ions may be used alone or as a mixture of two or more.

  The electrolyte solution containing these ions can be either aqueous or non-aqueous, but is preferably aqueous. Specifically, an aqueous solution of an acid or salt that forms ions containing a halogen atom is used. The concentration of the acid or salt is preferably 0.0001 to 10% by mass, more preferably 0.0005 to 5% by mass, and still more preferably 0.0005 to 1% by mass.

  The electrolyte solution may contain an acidic compound or basic compound that is different from the acid or salt that forms ions containing halogen atoms. By containing such different kinds of acidic compounds and basic compounds, the reaction rate such as promoting or suppressing the anodic oxidation rate can be controlled. Examples of such acidic compounds include sulfuric acid, nitric acid, acetic acid, hydrogen peroxide, oxalic acid, phosphoric acid, chromic acid, glycerophosphoric acid and the like in addition to the above-mentioned halide or acid of its oxidant ion. Is not to be done. Such basic compounds include, but are not limited to, sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonia and the like. These concentrations are preferably in the range of 0.001 to 1000, more preferably 0.01 to 50, and still more preferably 0.04 to 5 in terms of molar ratio to the halogen atom-containing ions.

  The electrolyte solution may contain a water-soluble titanium compound. A water-soluble titanium compound is generally hydrolyzed in an aqueous solution to produce titanium oxide. By containing this, the surface of the porous titanium oxide generated by electrolytic oxidation is further hydrolyzed by hydrolysis. Titanium oxide is generated, and the structure can be strengthened by preventing re-dissolution of the porous titanium oxide in the electrolyte solution. Examples of such water-soluble titanium compounds include titanium alkoxides such as titanium isopropoxide, titanium trichloride, titanium tetrachloride, titanium fluoride, ammonium tetrafluorotitanate, titanium sulfate, and titanyl sulfate. Is not to be done. The concentration is preferably in the range of 0.001 to 1000, more preferably 0.01 to 50, and still more preferably 0.04 to 5 in terms of molar ratio to the halogen atom-containing ions.

  The porous titanium-titanium oxide composite obtained by the above materials and electrolytic oxidation conditions may be subjected to post-treatment such as heat treatment, pressure treatment, electron beam irradiation, light irradiation at an absorption wavelength of titanium oxide, if necessary. By performing, it can be crystallized into an arbitrary crystal type. For example, in the case of heat treatment, crystallization is performed by performing treatment at a temperature of 100 ° C. to 1200 ° C., preferably 150 ° C. to 800 ° C., for 10 minutes to 500 minutes, preferably 10 minutes to 300 minutes. Even after these treatments, the structure of the porous titanium oxide does not collapse.

  An oxide semiconductor may be further formed on the obtained porous titanium-titanium oxide composite for the purpose of further increasing the surface area. As a method for forming an oxide semiconductor, a vapor deposition method such as a vacuum deposition method, a chemical deposition method, or a sputtering method, a liquid phase method such as a spin coating method, a dip coating method, or a liquid phase growth method, a thermal spraying method, or a solid phase method. Examples include a solid phase method such as a method using a reaction, a heat treatment method, and a method of applying a semiconductor fine particle colloid.

  The particle size of the semiconductor fine particles is generally on the order of nm to μm, but the particle size of the primary particles obtained from the diameter when the projected area is converted into a circle is preferably 5 to 200 nm, more preferably 8 to 100 nm. The average particle size of the secondary particles in the dispersion is preferably 0.01 to 10 μm.

  As a method for coating semiconductor fine particles, the roller method, the dip method, etc. as the application system, the air knife method, the blade method, etc. as the metering system, and the wire bar method, the slide hopper method, etc. that can make the application and metering the same part , Extrusion method, curtain method and the like. Moreover, a spin method and a spray method are also preferable as a general purpose machine. As the wet printing method, intaglio, rubber plate, screen printing and the like are preferred, including three major printing methods of letterpress, offset and gravure. A film forming method may be selected from these according to the liquid viscosity and the wet thickness.

  After applying the semiconductor fine particles on the porous titanium-titanium oxide composite, the electrical contact between the semiconductor fine particles is improved, and the coating strength and the adhesion with the porous titanium-titanium oxide composite are improved. Therefore, heat treatment is preferable. In the heat treatment, the treatment is performed at a temperature of 100 ° C. to 1200 ° C., preferably 300 ° C. to 800 ° C., for 10 minutes to 500 minutes, preferably 30 minutes to 160 minutes.

  After heat treatment, chemical plating treatment using titanium tetrachloride aqueous solution, electrochemical plating treatment using titanium trichloride aqueous solution, or crystal liquid using aqueous solution containing titanium fluoride, ammonium hexafluorotitanate, titanyl sulfate By performing the phase growth, the adhesion between the semiconductor fine particles and between the porous titanium-titanium oxide composite and the semiconductor fine particles can be further improved.

  The porous titanium-titanium oxide composite produced as described above can be suitably used as a catalyst or a catalyst carrier. Porous titanium-titanium oxide composite has much larger specific surface area than ordinary electrolytic oxide film, and it is an impurity that traps electrons, holes, phonons, or their composites that are generated due to the low amount of low-order oxides. There are few sites, and the efficiency with which they propagate is good. Therefore, when used for an ultraviolet absorber, a shielding agent, an adsorbent, a photoactive catalyst, or the like, particularly when used for a photocatalyst, their functions can be expected to be greatly improved as compared with the conventional case. In addition, when using as a catalyst support | carrier, normally, metals, such as platinum, nickel, silver, can be carry | supported and used.

  The porous titanium-titanium oxide composite produced as described above can be preferably used for a dye-sensitized photoelectric conversion element. The dye-sensitized photoelectric conversion element has a configuration in which a conductive layer, a photosensitive layer, a charge transport layer, and a transparent counter electrode conductive layer are laminated in this order. When using a porous titanium-titanium oxide composite, the titanium portion of the porous titanium-titanium oxide composite is used for the conductive layer, and the porous titanium-oxidation of the porous titanium-titanium oxide composite is used for the photosensitive layer. Use physical parts. In order to give strength to the photoelectric conversion element, a transparent substrate may be provided as a base of the transparent conductive layer. In addition, the layer which consists of a counter electrode conductive layer and the board | substrate provided arbitrarily is called a counter electrode, and a counter electrode needs to be transparent. Among such photoelectric conversion elements, a photovoltaic cell is connected to an external load in order to generate power, and a photoelectric sensor is a sensor made for the purpose of sensing optical information. Among photovoltaic cells, those in which the charge transport material is mainly composed of an ion transport material are called photoelectrochemical cells, and those whose main purpose is power generation by sunlight are called solar cells.

  In the photoelectric conversion element, the light incident on the photosensitive layer containing the porous titanium oxide sensitized by the dye excites the dye and the high energy electrons in the excited dye and the like are conducted by the porous titanium oxide. It is passed to the body and further diffuses to reach the conductive layer. At this time, the dye is an oxidant. In the photovoltaic cell, electrons in the conductive layer return to the dye oxidant through the transparent counter electrode conductive layer and the charge transport layer while working in the external circuit, and the dye is regenerated. The photosensitive layer serves as an anode and the transparent counter electrode conductive layer serves as a cathode. The constituent components of each layer may be diffused and mixed with each other at the boundary between the layers.

  In the porous titanium-titanium oxide composite, a titanium portion becomes a conductive layer and a porous titanium oxide portion becomes a photosensitive layer by adsorbing an appropriate sensitizing dye. In the photosensitive layer, the dye-sensitized porous titanium oxide acts as a photoreceptor, absorbs light, separates charges, and generates electrons and holes. Light absorption and the generation of electrons and holes thereby occur mainly in the dye, and the porous titanium oxide plays a role in receiving and transmitting these electrons. That is, the porous titanium oxide is an n-type semiconductor that gives an anode current due to conductor electrons under photoexcitation.

  The porous titanium oxide used for the photosensitive layer may be treated with a metal compound solution. Examples of the metal compound include scandium, yttrium, lanthanoid, hafnium, niobium, tantalum, gallium, indium, germanium, aluminum, zinc, strontium, tungsten, zirconium, and metal alkoxide, halide, etc. it can. The solution of the metal compound is usually an aqueous solution or an alcohol solution. The treatment refers to an operation of bringing the porous titanium oxide and the solution into contact with each other for a certain period of time before adsorbing the dye to the porous titanium oxide. The metal compound may or may not be adsorbed on the porous titanium oxide after contact. As a specific method for the treatment, a method of immersing porous titanium oxide in the solution can be mentioned as a preferred example. Further, a method in which the solution is sprayed for a predetermined time can be applied. Although the temperature of the solution at the time of immersion is not specifically limited, Typically, it is -10 degreeC-70 degreeC, Preferably it is 0 degreeC-40 degreeC. The immersion time is not particularly limited, and is typically 1 minute to 24 hours, and preferably 30 minutes to 15 hours. After the immersion, the porous titanium oxide may be washed with a solvent such as water. Moreover, you may heat in order to strengthen the coupling | bonding of the substance adhering to porous titanium oxide by immersion or a spray process. The heating conditions may be set similarly to the above-described conditions.

  The sensitizing dye used in the photosensitive layer is not particularly limited as long as it has absorption characteristics in the visible region and near-infrared region and can sensitize the semiconductor, but metal complex dyes, organic dyes, natural dyes, and semiconductors are preferable. Those having a functional group such as carboxyl group, hydroxyl group, sulfonyl group, phosphonyl group, carboxylalkyl group, hydroxyalkyl group, sulfonylalkyl group, phosphonylalkyl group in the molecule of the dye are preferably used. As the metal complex dye, a complex of ruthenium, osmium, iron, cobalt, zinc, mercury (for example, mellicle chromium), metal phthalocyanine, chlorophyll, or the like can be used. Examples of organic dyes include, but are not limited to, cyanine dyes, hemicyanine dyes, merocyanine dyes, xanthene dyes, triphenylmethane dyes, metal-free phthalocyanine dyes, and the like. As a semiconductor that can be used as a dye, an amorphous semiconductor having a large i-type light absorption coefficient, a direct transition semiconductor, or a fine particle semiconductor that exhibits a quantum size effect and efficiently absorbs visible light is preferable. Usually, one of various semiconductors, metal complex dyes and organic dyes, or two or more kinds of dyes can be mixed in order to make the wavelength range of photoelectric conversion as wide as possible and increase the conversion efficiency. Further, the dye to be mixed and its ratio can be selected so as to match the wavelength range and intensity distribution of the target light source.

  As a method for attaching the dye to the metal oxide, a solution in which the dye is dissolved in a solvent is applied on the metal oxide by spray coating, spin coating, or the like, and then dried. In this case, the substrate may be heated to an appropriate temperature. Alternatively, a method in which titanium oxide is immersed in a solution and adsorbed can be used. The immersion time is not particularly limited as long as the dye is sufficiently adsorbed, but is preferably 10 minutes to 30 hours, more preferably 10 minutes to 20 hours. Moreover, you may heat a solvent and a board | substrate when immersing as needed. The concentration of the dye in the case of a solution is preferably about 1 to 1000 mmol / L, preferably about 10 to 500 mmol / L.

  The solvent to be used is not particularly limited, but water and an organic solvent are preferably used. Examples of the organic solvent include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, and t-butanol, acetonitrile, propionitrile, methoxypropionitrile, glutaronitrile, and the like. Nitriles, aromatic hydrocarbons such as benzene, toluene, o-xylene, m-xylene and p-xylene, aliphatic hydrocarbons such as pentane, hexane and heptane, alicyclic hydrocarbons such as cyclohexane, acetone and methyl ethyl ketone , Ketones such as diethyl ketone and 2-butanone, ethers such as diethyl ether and tetrahydrofuran, ethylene carbonate, propylene carbonate, nitromethane, dimethylformamide, dimethyl sulfoxide, hexamethylphosphoa , Dimethoxyethane, γ-butyrolactone, γ-valerolactone, sulfolane, dimethoxyethane, adiponitrile, methoxyacetonitrile, dimethylacetamide, methylpyrrolidinone, dimethyl sulfoxide, dioxolane, sulfolane, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, Ethyldimethyl phosphate, tributyl phosphate, tripentyl phosphate, trihexyl phosphate, triheptyl phosphate, trioctyl phosphate, trinonyl phosphate, tridecyl phosphate, tris phosphate (trifluoromethyl), tris phosphate (pentafluoro) Ethyl), triphenyl polyethylene glycol phosphate, polyethylene glycol and the like.

  In order to reduce the interaction such as aggregation between the dyes, a colorless compound having properties as a surfactant may be added to the dye adsorbing solution and co-adsorbed on the titanium oxide. Examples of such colorless compounds include steroid compounds such as cholic acid having a carboxyl group or sulfo group, deoxycholic acid, chenodeoxycholic acid, taurodeoxycholic acid, sulfonates, and the like.

  It is preferable to remove the unadsorbed dye by washing immediately after the adsorption step. Washing is preferably performed using acetonitrile, an alcohol solvent or the like in a wet washing tank.

  After adsorbing the dye, porous using amines, quaternary ammonium salts, ureido compounds having at least one ureido group, silyl compounds having at least one silyl group, alkali metal salts, alkaline earth metal salts, etc. The surface of the fine titanium oxide may be treated. Examples of preferred amines include pyridine, 4-t-butylpyridine, polyvinylpyridine and the like. Examples of preferable quaternary ammonium salts include tetrabutylammonium iodide and tetrahexylammonium iodide. These may be used by dissolving in an organic solvent, or may be used as they are in the case of a liquid.

  The charge transport layer contains a charge transport material having a function of replenishing electrons to the oxidant of the dye. The charge transport material used in the dye-sensitized solar cell described above may be a charge transport material related to ions or a charge transport material related to carrier movement in a solid. Examples of the charge transport material in which ions are involved include a solution in which a redox counter ion is dissolved, a gel electrolyte composition in which a polymer matrix gel is impregnated with a solution of a redox pair, a solid electrolyte composition, and the like. Examples of the charge transport material involved in the electron transport material include an electron transport material and a hole transport material. A plurality of these charge transport materials may be used in combination.

The electrolyte solution as a charge transport material involving ions is preferably composed of an electrolyte, a solvent, and an additive. Examples of the electrolyte used in the electrolytic solution, iodine and iodide (LiI, NaI, KI, CsI, metal iodide such as CaI _2, tetraalkylammonium iodide, pyridinium iodide, quaternary ammonium such as imidazolium iodide A combination of bromine and bromide (metal bromide such as LiBr, NaBr, KBr, CsBr, CaBr, CaBr ₂ , quaternary ammonium compound bromide such as tetraalkylammonium bromide, pyridinium bromide, etc.) Examples thereof include metal complexes such as Russianate-ferricyanate and ferrocene-ferricinium ions, sulfur compounds such as sodium polysulfide and alkylthiol-alkyldisulfides, viologen dyes, and hydroquinone-quinone. Among them, a I _2, LiI or pyridinium iodide, electrolyte obtained by combining the quaternary ammonium compound iodine salt such as imidazolium iodide. The electrolyte may be used as a mixture.

  Any solvent can be used as long as it is generally used in electrochemical cells and batteries. Specifically, acetic anhydride, methanol, ethanol, tetrahydrofuran, propylene carbonate, nitromethane, acetonitrile, dimethylformamide, dimethyl sulfoxide, hexamethylphosphoamide, ethylene carbonate, dimethoxyethane, γ-butyrolactone, γ-valerolactone, sulfolane, dimethoxy Ethane, propiononitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, dimethylacetamide, methylpyrrolidinone, dimethyl sulfoxide, dioxolane, sulfolane, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, ethyldimethyl phosphate, tributyl phosphate, phosphorus Tripentyl phosphate, trihexyl phosphate, triheptyl phosphate, trioctyl phosphate, trinonyl phosphate, phosphoric acid Tridecyl, tris phosphate (trifluoromethyl), tris phosphate (pentafluoroethyl), triphenyl polyethylene glycol phosphate, polyethylene glycol, and the like can be used. In particular, propylene carbonate, ethylene carbonate, dimethyl sulfoxide, dimethoxyethane, acetonitrile, γ-butyrolactone, sulfolane, dioxolane, dimethylformamide, dimethoxyethane, tetrahydrofuran, adiponitrile, methoxyacetonitrile, methoxypropionitrile, dimethylacetamide, methylpyrrolidinone, dimethylsulfoxide , Dioxolane, sulfolane, trimethyl phosphate and triethyl phosphate are preferred. Also, room temperature molten salts can be used. Here, the room temperature molten salt is a salt composed of an ion pair that is melted at room temperature (that is, in a liquid state), and is usually an ion pair that has a melting point of 20 ° C. or lower and is liquid at a temperature exceeding 20 ° C. Is a salt. The solvent may be used alone or in combination of two or more.

  Further, it is preferable to add a basic compound such as 4-t-butylpyridine, 2-picoline, or 2,6-lutidine to the above-described molten salt electrolyte composition or electrolytic solution. A preferable concentration range when adding the basic compound to the electrolytic solution is 0.05 to 2 mol / L. When added to the molten salt electrolyte composition, the basic compound preferably has an ionic group. The mass ratio of the basic compound to the entire molten salt electrolyte composition is preferably 1 to 40% by mass, more preferably 5 to 30% by mass.

  The material that can be used as the polymer matrix is not particularly limited as long as the polymer matrix alone, or the solid state or gel state is formed by the addition of a plasticizer, the addition of a supporting electrolyte, or the addition of a plasticizer and a supporting electrolyte. Generally used so-called polymer compounds can be used.

  Examples of the polymer compound exhibiting characteristics as the polymer matrix include hexafluoropropylene, tetrafluoroethylene, trifluoroethylene, ethylene, propylene, acrylonitrile, vinylidene chloride, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, methyl Examples thereof include polymer compounds obtained by polymerizing or copolymerizing monomers such as acrylate, ethyl acrylate, methyl methacrylate, styrene, and vinylidene fluoride. These polymer compounds may be used alone or in combination. Among these, a polyvinylidene fluoride polymer compound is particularly preferable.

  Further, instead of the ion conductive electrolyte, an organic solid hole transport material, an inorganic solid hole transport material, or a material in which both are combined can be used.

Examples of organic hole transport materials that can be preferably used include triphenylene derivatives, oligothiophene compounds, polypyrrole, polyacetylene and / or derivatives thereof, poly (p-phenylene) and / or derivatives thereof, poly (p-phenylene vinylene) and Conductive polymers such as / or derivatives thereof, polythienylene vinylene and / or derivatives thereof, polythiophene and / or derivatives thereof, polyaniline and / or derivatives thereof, polytoluidine and / or derivatives thereof can also be preferably used. At that time, a compound containing a cation radical such as tris (4-bromophenyl) aminium hexachloroantimonate may be added to the hole transport material in order to control the dopant level. Further, a salt such as Li [(CF ₃ SO ₂ ) ₂ N] may be added to perform potential control (space charge layer compensation) on the surface of the metal oxide semiconductor.

A p-type inorganic compound semiconductor can be used as the inorganic hole transport material, and the band gap is preferably 2 eV or more, more preferably 2.5 eV or more. Further, the ionization potential of the p-type inorganic compound semiconductor needs to be smaller than the ionization potential of the dye adsorption electrode in order to reduce the holes of the dye. Although the preferable range of the ionization potential of the p-type inorganic compound semiconductor varies depending on the dye used, it is generally preferably 4.5 to 5.5 eV, more preferably 4.7 to 5.3 eV. Preferred p-type inorganic compound semiconductor is a compound semiconductor containing monovalent copper, CuI and examples _{thereof, CuSCN, CuInSe 2, Cu (} In, Ga) Se 2, CuGaSe 2, Cu2O, CuS, CuGaS 2, CuInS 2 CuAlSe _{2 and the} like. Among these, CuI and CuSCN are preferable, and CuI is most preferable. Examples of other p-type inorganic compound semiconductors include GaP, NiO, CoO, FeO, Bi ₂ O ₃ , MoO ₂ , Cr ₂ O _{3 and the} like.

  The charge transport layer can be formed by one of two methods. The first method is a method in which a photosensitive layer and a counter electrode are bonded together, and a liquid charge transport layer is sandwiched between the gaps. The second method is a method in which a charge transport layer is directly provided on the photosensitive layer, and the counter electrode is subsequently provided.

  In the case of the former method, when sandwiching the charge transport layer, a normal pressure process using capillary action due to immersion or the like, or a vacuum process in which the gas phase in the gap is replaced with a liquid phase at a pressure lower than normal pressure can be used. .

  When a wet charge transport layer is used in the latter method, a counter electrode is usually applied in an undried state to prevent liquid leakage at the edge. Moreover, when using a gel electrolyte composition, you may solidify by methods, such as superposition | polymerization, after apply | coating this with a wet process. Solidification may be performed before or after applying the counter electrode. In the case of forming a charge transport layer made of an electrolytic solution, a wet organic hole transport material, a gel electrolyte composition, or the like, the same method as the method for forming a semiconductor fine particle layer described above can be used.

  When a solid electrolyte composition or a solid hole transport material is used, a charge transport layer can be formed by a dry film forming process such as a vacuum deposition method or a CVD method, and then a counter electrode can be provided. The organic hole transport material can be introduced into the electrode by a vacuum deposition method, a casting method, a coating method, a spin coating method, a dipping method, an electrolytic polymerization method, a photoelectrolytic polymerization method, or the like. The inorganic solid compound can be introduced into the electrode by a casting method, a coating method, a spin coating method, a dipping method, an electrolytic deposition method, an electroless plating method, or the like.

  The counter electrode may have a single layer structure of a counter electrode conductive layer made of a conductive material, or may be composed of a counter electrode conductive layer and a support substrate. The support substrate is preferably a transparent glass substrate or a plastic substrate, and the above-mentioned conductive agent can be applied or vapor-deposited thereon. Since the dye-sensitized photoelectric conversion element irradiates light from the counter electrode side, it is necessary that the light transmittance be large. Specifically, the light transmittance is preferably 30% or more, more preferably 50% or more. On the other hand, the surface resistance of the counter electrode is preferably low, but as the light transmittance increases, the surface resistance of the counter electrode increases, and preferably 50 Ω / sq. Or less, more preferably 20 Ω / sq. It is as follows.

  The material used for the counter electrode conductive layer is not limited as long as it has a low specific resistance such as metals such as platinum, gold, nickel, titanium, aluminum, copper, silver, and tungsten, carbon materials, and conductive organic materials, but has low transparency. In the case of using a material, in order to improve the overall light transmittance, it is necessary to form a thin wire pattern of a conductive material on a support substrate to produce a counter electrode with low surface resistance and high transparency.

In addition, as a highly transparent conductive material, indium tin oxide (ITO (In ₂ O ₃ : Sn)) in which a metal oxide such as tin or zinc is slightly doped with another metal element, Indium Zinc Oxide (IZO (In ₂ O ₃ : Zn)), Fluorine doped Tin Oxide (FTO (SnO ₂ : F)), Aluminum doped zinc oxide (Aluminum There are conductive films made of metal oxides such as doped zinc oxide (AZO (ZnO: Al)), etc., and a small amount of metal (platinum, gold, silver, copper, aluminum, magnesium, indium, etc.), carbon, etc. You may use together.

  The counter electrode may be installed by directly applying, plating, or vapor-depositing (PVD, CVD) a conductive agent on the charge transport layer, or by attaching the conductive layer side of the substrate having the conductive layer. A metal lead may be used for the purpose of reducing the resistance of the counter electrode. The metal lead is preferably made of a metal such as platinum, gold, nickel, titanium, aluminum, copper, or silver, and particularly preferably made of aluminum or silver. It is preferable that a metal lead is disposed on the transparent substrate by vapor deposition, sputtering, or the like, and a transparent counter electrode conductive layer made of fluorine-doped tin oxide, ITO film or the like is disposed thereon. It is also preferable that a metal lead is provided on the transparent counter electrode conductive layer after the transparent counter electrode conductive layer is provided on the transparent substrate. The decrease in the amount of incident light due to the installation of the metal lead is preferably within 10%, more preferably 1 to 5%.

  According to the present invention, the uniformity and denseness can be quantitatively evaluated by evaluating the porous titanium-titanium oxide composite produced by such a method with an image sensor. Next, the evaluation procedure will be described in detail.

  In the evaluation, it is necessary to first store the hue that is a standard product in the image sensor. The standard product here may be, for example, a small porous titanium-titanium oxide composite sample whose porous titanium oxide is known to be uniformly and densely produced, or any color sample. May be used. In any case, it is important to determine the color, saturation, and brightness of the reference color.

  After memorizing the standard color, scan the porous titanium-titanium oxide composite to be measured with an image sensor and evaluate the area of the standard color that matches the range of color, saturation, and brightness. . The area of the conforming portion is generally represented by the number of pixels, and this value increases as it becomes more uniform and precise. That is, the uniformity and denseness of the porous titanium oxide portion can be quantitatively evaluated by the number of pixels obtained by this method.

  In performing the above measurement, the porous titanium-titanium oxide composite may be used as it is. However, when it is desired to more clearly express the hue, the dye is adsorbed on the porous titanium-titanium oxide composite. Can also be measured. Any pigment may be used at this time. However, if the pigment has a lightness that is too low, the contrast becomes difficult to understand. When using this method, of course, the standard product must also have the same color.

  It is known that the number of pixels obtained by this method has a correlation with performance when a porous titanium-titanium oxide composite is used as a photoelectric conversion element material or the like. Therefore, the number of pixels measured by the image sensor can be used as a quality control reference value when the porous titanium-titanium oxide composite is industrially produced.

  By the method of the present invention, the uniformity and denseness of porous metal-metal oxide composites including porous titanium-titanium oxide composites can be quantitatively evaluated.

  Next, the present invention will be described in more detail by way of examples.

[Example 1]
A JIS class 1 titanium plate (size 16 × 35 mm, thickness 0.4 mm) finished in the annealing process was prepared as a material for electrolytic oxidation. When this was observed with a scanning electron microscope, there were approximately 1400 concave portions that seemed to be oil pits per square millimeter, and the average shape was about 30 μm long and about 2 μm wide. . When this titanium plate was sliced thinly and the cross section was observed with a scanning electron microscope, the depth of the recess was about 0.3 μm.

  Using this titanium plate, electrolytic oxidation was performed by the following procedure.

  First, as a pretreatment, the titanium plate was ultrasonically cleaned in ethanol for 5 minutes to remove oils and fats adhering to the surface. The titanium plate after the pretreatment was used as an anode, and it was fixed to the upper part of a 1000 ml beaker so that the distance was 20 mm in parallel with a substantially identical cathode plate. This beaker was filled with an aqueous solution of perchloric acid having a concentration of 0.8 mmol / l until the titanium plate was immersed by about half. The titanium plate (anode) and the cathode were each connected to a DC power source and a cord, and a current of 30 V was kept flowing for 60 minutes. The value of the current flowing during this period was 80 to 100 mA, and the total charge amount for 60 minutes was 180 coulombs. The titanium plate after electrolytic oxidation was lightly washed with distilled water and dried with high-pressure air.

  The titanium plate after the electrolytic oxidation was densely and uniformly covered with a white substance on the entire surface. This was observed with a scanning electron microscope, and it was confirmed that the white substance was a nanotube-shaped porous titanium oxide.

  The surface of the porous titanium oxide was subjected to color extraction with an image sensor (Keyence CV-3500) for image analysis.

  The camera was a CV-200C (2 million pixel color camera), a high-resolution lens CA-LH8, and illumination was performed with a pair of LED illumination (bar system) by oblique illumination. The distance between the camera and the object was 150 mm, the distance between the lights was 180 mm, the height between the lights and the objects was 80 mm, and the illumination bar was set at an angle of 45 degrees.

The color extraction conditions of the image sensor are as follows. The extraction area is set to 1 cm ² , H (hue) is minimum 3 to maximum 150, S (saturation) is minimum 0 to maximum 88, and V (lightness) is minimum 100 to maximum 255. And the number of pixels was obtained under these conditions.

FIG. 1 schematically shows the positional relationship between an image sensor and an object for measurement. An evaluation object 2 was placed on the sample stage 1. A pair of rod-shaped illuminations (light sources) 3 was disposed at a position 80 mm above the evaluation target 2. The mutual space | interval of the illumination 3 was 180 mm. The CCD camera 4 of the image sensor was placed at a position 150 mm above the evaluation object 2 at a position just between the pair of illuminations 3, and the evaluation object was imaged. The image signal from the CDD camera 4 is taken into the controller 5, and the controller 5 performs the above-described calculation of hue, saturation, brightness, extraction of pixels, calculation of the number of extracted pixels, and the like.
[Example 2]
Samples with electrolytic oxidation times changed to 30 minutes, 60 minutes, 90 minutes, and 120 minutes by the method of Example 1 were compared and the number of pixels was compared. Increased number of pixels. FIG. 2 shows the results obtained for the relationship between the number of extracted pixels and the electrolytic oxidation time.
[Example 3]
The sample obtained by the method of Example 2 was immersed in an ethanol solution (3.0 × 10 ⁻⁴ mol / L) of ruthenium dye (Rutenium 535-bisTBA: manufactured by SOLARONIX) for 15 hours to adsorb the dye. Thereafter, pixels were extracted based on the redness of the sample on which the dye was adsorbed. As a result, the higher the number of pixels of whiteness obtained in Example 2, the higher the number of pixels from which the dye-adsorbed redness was extracted, and a correlation between the two was obtained. Further, the sample slice adsorbed with the dye was immersed in an alkaline solution (10 mM NaOH aqueous solution) to re-separate the dye, and the amount of dye was calculated from the absorbance. As a result, the correlation between the number of extracted pixels and the amount of dye adsorbed in Example 2 was found. Obtained. FIG. 3 shows the results obtained for the relationship between the number of extracted pixels and the dye adsorption amount.

[Example 4]
The dimension of the titanium plate used in Example 1 was adjusted to 10 cm × 10 cm to obtain a material for electrolytic oxidation, and electrolytic oxidation was performed according to the following procedure.

  First, as a pretreatment, the titanium plate was ultrasonically cleaned in ethanol for 5 minutes to remove oils and fats adhering to the surface. Titanium plate that has been pre-treated is used as an anode so that a 1.2t × 200W × 150L cathode plate (product name: EXEROD R2000 / 0.1μ, material TP340, manufactured by Toho Tech Co., Ltd.) is parallel to the distance and 20 mm. And fixed to an electrolytic cell of 25 cm × 15 cm × 22 cm. The electrolytic bath was filled with 7000 ml of an aqueous solution of perchloric acid having a concentration of 0.8 mmol / l until the entire surface of the titanium plate was immersed. The titanium plate (anode) and cathode were each connected to a DC power source and a cord, and a current of 60 V was continuously applied for 60 minutes. The value of current flowing during this period was 550 to 900 mA, and the total charge amount for 60 minutes was 3000 coulombs. The titanium plate after electrolytic oxidation was lightly washed with distilled water and dried with high-pressure air.

In the area analysis (color extraction) for the purpose of extracting only the color to be detected by the image sensor, the area of 1 cm ² of the porous titanium oxide slice (sample A) obtained by performing the electrolytic oxidation time in Example 2 for 120 minutes Later, binarization (color binary) processing was performed. The color extraction value of the designated color thus obtained was 144 for H (hue), 26 for S (saturation), and 107 for V (lightness). The number of extracted pixels per 1 cm ² was 10,707 pixels (pixels). FIG. 4 is a diagram of a monitor image showing pixels extracted from the sample A by the binarization process. In the drawing, the white portion is extracted.

Based on the above, the total area of the 10 cm × 10 cm electrolytically oxidized porous titanium oxide (sample B) surface area was analyzed with an image sensor, and the number of extracted pixels subjected to binarization was 522,916 pixels / 100 cm. ² . In comparison with the sample of the basic setting value per unit area, the sample A was 10,707 pixels / 1 cm ² , the sample B was 5,229 pixels / 1 cm ² , and the density was 49% of the sample A. FIG. 5 is a diagram of a monitor image showing pixels extracted from the sample B by the binarization process. In the drawing, the white portion is extracted.

  Further, when the uniformity was confirmed on the binarized image processing screen, the sample B was dense at the center and had many white portions, and the periphery was rough and partially black, so that it could be used as an index of uniformity.

  According to the present invention, the state of a photoelectric conversion element such as a dye-sensitized solar cell or an optical sensor, or a porous metal-metal oxide complex used as a photocatalyst (for example, denseness and uniformity) is quantitatively determined. It becomes possible to evaluate to. Therefore, by applying the present invention, it is possible to produce a photoelectric conversion element or a photocatalyst with better performance by evaluating the porous metal-metal oxide composite in advance.

FIG. 3 is a diagram illustrating an arrangement relationship between an object and an image sensor in the first embodiment. It is a graph which shows the relationship between the whiteness by the electrolytic oxidation time of the porous titanium-titanium oxide composite in Example 2, and the number of extracted pixels. 10 is a graph showing the relationship between the amount of dye adsorption and the number of extracted pixels in Example 3. It is a figure which shows the monitor image which binarized the sample A in Example 4. FIG. It is a figure which shows the monitor image which binarized the sample B in Example 4. FIG.

Explanation of symbols

1 Sample stage 2 Object 3 Illumination (light source)
4 CCD camera 5 Controller

Claims (6)

In the evaluation method for evaluating the surface state of the porous metal-metal oxide composite,
Using an image sensor, image the porous metal-metal oxide composite,
Calculating at least one of hue, saturation and brightness of each pixel in the captured image;
Extracting a pixel in which at least one of the calculated hue, saturation, and brightness is within a predetermined range or a predetermined value;
An evaluation method comprising quantitatively evaluating a porous metal oxide portion based on an extracted pixel.   The evaluation method according to claim 1, wherein the pixel is extracted based on whiteness of the porous oxide portion, and the porous metal oxide portion is quantitatively evaluated according to the number of extracted pixels.   The porous metal oxide portion is quantitatively evaluated by a ratio between the number of extracted pixels and the total number of pixels corresponding to the porous metal-metal oxide composite in the captured image. 1. The evaluation method according to 1. In the evaluation method for evaluating the surface state of the porous metal-metal oxide composite,
Adsorbing a dye on the porous metal-metal oxide composite;
Using an image sensor, image the porous metal-metal oxide complex after dye adsorption,
Based on at least one of the hue, saturation, and brightness of each pixel in the captured image, the coloring degree is calculated for each pixel,
Extract pixels based on the degree of coloring,
An evaluation method comprising quantitatively evaluating a porous metal oxide portion based on an extracted pixel.   The evaluation for each partial region of the surface of the porous metal-metal oxide composite is repeatedly performed while scanning the image sensor with respect to the porous metal-metal oxide composite. 5. The evaluation method according to any one of 4 above.   The evaluation method according to any one of claims 1 to 4, wherein the porous metal-metal oxide composite is a porous titanium-titanium oxide composite.

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