JP2013258127A - Photoelectrode for dye-sensitized solar cell and method for manufacturing the same, and dye-sensitized solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that, since the conventional art requires a great deal of time for manufacturing processes, a manufacturing method for continuous production is to be developed for industrial utilization.SOLUTION: A photoelectric conversion layer can be formed with high adhesion on a translucent substrate by subjecting a coating film to roll pressing treatment, the coating film being formed by using a paste containing semiconductor particles and coating/drying the paste on a transparent substrate, and a photoelectrode for a dye-sensitized solar cell, by including which a dye-sensitized solar cell exhibiting high photoelectric conversion efficiency can be obtained, is obtained. The photoelectrode is specifically effective when a plastic substrate is used as the translucent substrate. A dye-sensitized solar cell with favorable performance can be obtained by the roll pressing treatment.

Description

  The present invention relates to a dye-sensitized solar cell photoelectrode, a method for producing the same, and a dye-sensitized solar cell.

The dye-sensitized solar cell was developed by Gretzel et al. In Switzerland, and has advantages such as higher photoelectric conversion efficiency and lower manufacturing cost than other general batteries. As this dye-sensitized solar cell, for example, configurations shown in Non-Patent Document 1 and Patent Document 1 are known.
The dye-sensitized solar cell disclosed in Patent Literature 1 is disposed on a translucent substrate in which a transparent conductive layer is formed on a plastic translucent support (base material), and the translucent substrate. The photoelectric conversion layer (the oxide semiconductor porous film supporting the sensitizing dye), the electrolyte portion, and the counter electrode are laminated.
The photoelectric conversion layer in this is formed in the following processes. First, an aqueous paste containing at least two types of titania particles having different average particle diameters is applied onto a translucent support to form a coating film, and then the coating film is pressed to form a layer. Then, the photoelectric conversion layer is formed by supporting the sensitizing dye on the formed layer.

  According to the dye-sensitized solar cell thus configured, even when plastic is used for the translucent support, the photoelectric conversion layer can be formed on the translucent support by increasing the adhesion. Thus, the photoelectric conversion efficiency can be increased, and the same performance as a dye-sensitized solar cell using a glass transparent substrate can be obtained. (For example, Non-Patent Document 2)

  However, in the manufacturing methods of Patent Document 1 and Non-Patent Document 2, since the process time required for manufacturing becomes enormous, it is necessary to develop a manufacturing method for continuous production for industrial use.

International Publication No. 2007/100095 JP 2011-142010 A

Nature, 353, p. 737-740, 1991 SOL. Energy Mater. Sol. Cel. 94, 812, 2010

  As a manufacturing method for industrially continuously producing dye-sensitized solar cells, the present inventors used a paste containing semiconductor particles and rolled a coating film formed by applying and drying the paste on a transparent substrate. By performing the press treatment, the photoelectric conversion layer can be formed on the translucent substrate with high adhesion, and the resulting dye-sensitized solar cell can exhibit high photoelectric conversion efficiency. A photoelectrode for a battery was obtained, which was found to be effective particularly when a plastic substrate was used as the translucent substrate, and the present invention was completed.

  A first aspect of the present invention is a light in which a functional semiconductor layer is provided on a transparent conductive layer of a transparent substrate in which a transparent conductive layer is formed on an elastic plastic transparent support. A photoelectrode for a dye-sensitized solar cell in which a sensitizing dye is supported on the functional semiconductor layer of the electrode structure, wherein the functional semiconductor layer is in a state in which the roll-pressed layer is in contact with the transparent conductive layer The surface of the layer subjected to the roll press treatment has a roll press trace extending in parallel with the roll press treatment direction, and the surface roughness Ra is 50 nanometers or less.

The thickness of the functional semiconductor layer that has been roll-pressed may be 1 to 40 μm.
Further, the functional semiconductor layer may contain particles having an average particle diameter of 2 to 40 nm.

The functional semiconductor layer may contain two or more kinds of particles having different average particle diameters, and the average particle diameter of at least one kind of particles may be 2 to 40 nm.
At this time, in two or more kinds of particles having different average particle diameters, the content ratio of particles having an average particle diameter of 2 to 40 nm may be 50 to 95% by mass.

  The light transmission at a wavelength of 500 nm is 20 to 85% and the light transmittance at a wavelength of 700 nm of the laminate comprising the light-transmitting substrate and the roll-pressed layer of the functional semiconductor layer in the photoelectrode structure. It may be 30 to 85%.

  The dye-sensitized solar cell according to the second aspect of the present invention includes the photoelectrode for dye-sensitized solar cell of the present invention, and the photoelectrode for dye-sensitized solar cell faces the counter electrode through the electrolyte portion. It is characterized by being provided.

  The third aspect of the present invention is formed by laminating a photoelectric conversion layer on the transparent conductive layer of the transparent substrate formed by forming a transparent conductive layer on an elastic plastic transparent support. A method for producing a photoelectrode for a dye-sensitized solar cell, wherein the photoelectric conversion layer contains particles and a sensitizing dye, and a paste containing the particles is placed on the transparent conductive layer. After coating and forming a coating film, the coating film is subjected to roll press treatment at a pressure of 40 MPa or more and 500 MPa or less to form a roll press trace; and a step of supporting a sensitizing dye on a layer obtained by the roll press treatment; It is characterized by including.

  In the method for producing a photoelectrode for a dye-sensitized solar cell of the present invention, as the translucent substrate, a transparent conductive layer whose surface is subjected to UV-ozone treatment may be used.

According to the method for producing a dye-sensitized solar cell photoelectrode of the present invention, when two or more kinds of semiconductor particles having different specific average particle diameters are contained in the photoelectric conversion layer, the increase in the photoelectric conversion layer is included. High light absorption efficiency due to the so-called light confinement effect can be achieved for the dye-sensitive dye.
Further, according to the production method of the present invention, since the photoelectric conversion layer is formed by a specific method in which the coating film is roll-pressed using a specific paste, the semiconductor particles are densely packed by roll-pressing. When the light-transmitting substrate is a plastic substrate, the semiconductor particles adhere to the surface of the transparent conductive layer of the light-transmitting substrate due to its flexibility, and an extremely good electron flow is achieved. As a result, a dye-sensitized solar cell with good performance can be obtained.
That is, for example, even when using a plastic substrate that has conventionally been difficult to obtain high light absorption efficiency, the photoelectric conversion layer can be formed on the light-transmitting substrate with high adhesion. Even when a substrate is used, a photoelectrode for a dye-sensitized solar cell that can provide a dye-sensitized solar cell that can maintain a high level of photoelectric conversion efficiency even when the amount of incident light is changed should be reliably manufactured with good reproducibility. Can do.

  In addition, according to the production method of the present invention, since the operation can be performed under room temperature conditions, the operation can be easily performed and heating is hardly required, and the material to be used is small compared to the conventional production method. It is possible to produce at a high speed, and a large area can be processed uniformly, so that the manufacturing cost is reduced. Further, since the roll press process is sufficient at a low pressure, advantages such as energy saving can be obtained.

  According to the photoelectrode for dye-sensitized solar cell of the present invention, even when a plastic substrate is used as the translucent substrate, the dye-sensitized solar that can maintain a high level of photoelectric conversion efficiency even if the incident light amount is changed. A battery can be provided.

It is sectional drawing for description which shows an example of the structure of the cell which comprises the dye-sensitized solar cell of this invention. It is sectional drawing for description which shows an example of the method of manufacturing the photoelectrode for dye-sensitized solar cells of this invention. It is sectional drawing for description which shows another example of a structure of the cell which comprises the dye-sensitized solar cell of this invention. It is sectional drawing for description which shows an example of the method of manufacturing the photoelectrode for dye-sensitized solar cells of another example of this invention. It is a figure which shows the shape of an example of embodiment of this invention. It is a figure which shows the shape by the conventional method. It is a figure for demonstrating the measuring method of surface roughness Ra in this invention. It is a figure for demonstrating the measuring method of surface roughness Ra in this invention.

  Hereinafter, the present invention will be specifically described. In the present specification, the numerical range indicated in the form of “A to B” means A or more and B or less (where A <B) unless otherwise specified.

<First Embodiment>
FIG. 1 is a cross-sectional view for explaining an example of the structure of a cell constituting the dye-sensitized solar cell of the present invention.

[Photoelectric conversion element]
A cell (hereinafter also referred to as “photoelectric conversion element”) 10 constituting the dye-sensitized solar cell is a photoelectrode (hereinafter referred to as a photoelectrode for dye-sensitized solar cell) in which a photoelectric conversion layer 23 is formed on a light-transmitting substrate 21. These are also referred to as “photoelectrodes”) 20 and a counter electrode 16 in which a conductive layer (not shown) made of, for example, platinum or the like is formed on a translucent substrate (not shown). 23 and the conductive layer are arranged to face each other with the electrolyte portion 12 therebetween.

  The photoelectrode 20 functions as a negative electrode. Specifically, the translucent substrate 21 having a transparent conductive layer 21b (see FIG. 2A) and the transparent conductivity of the translucent substrate 21 are provided. The photoelectric conversion layer 23 provided by being stacked on the layer 21b is provided.

[Photoelectric conversion layer]
The photoelectric conversion layer 23 contains semiconductor particles (hereinafter referred to as “specific semiconductor particle group”) and a sensitizing dye and is roll-press treated. Specifically, the specific semiconductor particle group A functional coating layer 23α (see FIG. 2 (b)) containing paste containing a sensitizing dye is carried on a roll-press-treated functional semiconductor layer 23α.
Since the photoelectric conversion layer 23 has the functional semiconductor layer 23α subjected to the roll press process, the functional semiconductor layer 23α can be formed with a large number of nanopores. The ratio of the surface area of the semiconductor particles per unit area becomes extremely large, whereby a sufficient amount of the sensitizing dye can be carried, and high light absorption efficiency is obtained after all.

The photoelectric conversion layer 23 may be configured by containing semiconductor fine particles having an average particle diameter of 2 to 40 nm.
For example, when nano-sized semiconductor fine particles having an average particle diameter of about 20 nm are used (a case where the light confinement effect described below is not fully utilized), a photoelectric conversion layer having a high transmittance can be formed.
Further, when the photoelectric conversion layer 23 contains two or more kinds of semiconductor particles having different average particle diameters, for example, nano-sized semiconductor particles having an average particle diameter of about 20 nm tend to easily transmit long-wavelength light. For example, when so-called semiconductor particles having an average particle diameter of about 100 nm are mixed, light is scattered and the optical path length in the functional semiconductor layer 23α is increased, so that a so-called optical confinement effect can be sufficiently obtained. As a result, sufficient light absorption efficiency is obtained for the sensitizing dye, and thus high photoelectric conversion efficiency is achieved in the dye-sensitized solar cell.

  In this photoelectric conversion element 10, a photoelectrode structure 20K (see FIG. 2C) in which a transparent conductive layer 21b and a functional semiconductor layer 23α are provided in this order on a translucent support 21a has a wavelength of 500 nm. The light transmittance is preferably 20 to 85%, and the light transmittance at a wavelength of 700 nm is preferably 30 to 85%. If the light transmittance is excessive, light is transmitted without internal scattering, so that there is a possibility that sufficient light absorption efficiency cannot be obtained in the photoelectrode, while the light transmittance is excessively low. If so, surface reflection may occur and light may not enter the photoelectrode.

[Semiconductor particles]
The semiconductor particles exhibit an electron transfer function, and specific examples of semiconductors constituting such semiconductor particles include TiO ₂ , SnO, ZnO, WO ₃ , Nb ₂ O ₅ , In _2. Oxide semiconductors such as O ₃ , ZrO ₂ , Ta ₂ O ₅ , TiSrO ₃ ; CdS, ZnS, In ₂ S, PbS, Mo ₂ S, WS ₂ , Sb ₂ S ₃ , Bi ₂ S ₃ , ZnCdS ₂ , CuS Sulfide semiconductors such as ₂ ; metal chalcogenides such as CdSe, In ₂ Se ₂ , WSe ₂ , PbSe, CdTe; and elemental semiconductors such as GaAs, Si, Se, InP, etc., for example, a composite of SnO and ZnO, A composite composed of two or more of these, such as a composite of TiO ₂ and Nb ₂ O ₅ can also be used. Moreover, the kind of semiconductor is not limited to these, It can also be used in mixture of 2 or more types.
As a semiconductor constituting the semiconductor particles, oxides of Ti, Zn, Sn, and Nb are preferable among the above, and TiO ₂ is particularly preferable.
As the titania particles made of TiO ₂ , those of anatase crystal type and rutile crystal type can be mentioned, and both can be used. Especially when anatase crystal type titania particles are used, a translucent support made of a plastic film is used. In the dye-sensitized solar cell by the body, the expected performance can be surely obtained.

When two or more kinds of semiconductor particles having different average particle diameters contained in a specific semiconductor particle group are used, they may be the same kind or different kinds, but the same kind. It is preferable.
As the semiconductor particles, titania particles are preferably used.

  The average particle size of the semiconductor particles having a small average particle size (hereinafter also referred to as “semiconductor small particles”) among the semiconductor particles constituting the specific semiconductor particle group is preferably 2 to 40 nm, more preferably 15 to 25 nm. is there. In addition, the semiconductor particles having a large average particle size among the semiconductor particles constituting the specific semiconductor particle group (hereinafter also referred to as “semiconductor large particles”) have light scattering ability and have an average particle size. Is preferably 50 nm or more, more preferably 80 to 400 nm, and particularly preferably 90 to 120 nm.

  It is preferable that the content rate of the semiconductor small particle in the specific semiconductor particle group which comprises the photoelectric converting layer 23 is 50-95 mass%, More preferably, it is 60-70 mass%. If the ratio of the small semiconductor particles is excessive, a sufficient light confinement effect by the large semiconductor particles cannot be obtained, and high light absorption efficiency cannot be obtained for the sensitizing dye. On the other hand, when the ratio of the semiconductor small particles is too small, the photoelectric conversion ability cannot be sufficiently obtained.

Moreover, it is preferable that the thickness of the functional semiconductor layer 23 (alpha) which should form the photoelectric converting layer 23 is 1-40 micrometers, More preferably, it is 3-30 micrometers. More preferably, it is 3-20 micrometers.
When the thickness of the functional semiconductor layer on which the photoelectric conversion layer is to be formed is too small, the dye-sensitized solar cell obtained because it cannot carry a sufficient amount of the sensitizing dye cannot obtain sufficient photoelectric conversion efficiency. It becomes a thing. On the other hand, when the thickness of the functional semiconductor layer on which the photoelectric conversion layer is to be formed is excessive, the energy due to recombination of charges is increased because the diffusion distance of electrons injected from the sensitizing dye in the resulting photoelectric conversion layer increases. Loss will increase.

[Sensitizing dye]
The sensitizing dye supported on the semiconductor particles in the photoelectric conversion layer 23 is not particularly limited as long as it exhibits a sensitizing action. N3 complex, N719 complex (N719 dye), Ru terpyridine complex (black dye), Ru Ru complexes such as diketonate complexes; organic dyes such as coumarin dyes, merocyanine dyes, polyene dyes; metal porphyrin dyes and phthalocyanine dyes, and the like. Among these, Ru complexes are preferred, and particularly visible light. N719 dyes and black dyes are preferred because they have a broad absorption spectrum in the region.
The N719 dye is a compound represented by (RuL ₂ (NCS) ₂ · 2TBA), and the Blackdye dye is a compound represented by (RuL ′ ₁ (NCS) ₃ · 2TBA). Where L is 4,4′-dicarboxy-2,2′-bipyridine, L ′ is 4,4 ′, 4 ″ -tetra-carboxy-2,2 ′, 2 ″ -terpyridine, and TBA is tetra Butylammonium chaotic. These can be used alone or in admixture of two or more.

The amount of the sensitizing dye supported in the photoelectric conversion layer 23 is 1 × 10 ⁻⁸ to 1 × 10 ⁻⁷ mol / cm ² , preferably 3 × 10 ^{−8 to} 7 ⁻⁷ per unit surface area of the functional semiconductor layer 23α. It is preferable to set it as ^x10 < ^-8 > mol / cm < ² >. Since the amount of the sensitizing dye supported is within this range, the sensitizing dye is supported as a monomolecular layer on the surface of the semiconductor particles, so that electrons excited in the sensitizing dye reduce the electrolyte in the electrolyte portion. Sufficient absorption efficiency can be obtained without causing energy loss.

[Translucent substrate]
The translucent substrate 21 constituting the photoelectric conversion element 10 of this example is formed by forming a transparent conductive layer 21b on a translucent support 21a.
As the translucent support 21a, those made of various materials such as glass and plastic can be used. From the viewpoint of translucency, heat resistance, chemical resistance, etc. It is preferable to use a plate-like or film-like cycloolefin polymer, a plate-like or film-like acrylurea-based polymer, a plate-like or film-like polyester, a plate-like or film-like polyethylene naphthalate, or the like.

Preferably the surface resistivity of the transparent substrate 21 is not more than 100Ω / cm ^2, and more preferably 15 [Omega] / cm ² or less. The surface resistance was measured by Loresta-GP model number MCP-T610 manufactured by Mitsubishi Chemical Analytech. This device complies with JIS K7194-1994. The unit is Ω / sq. Or it is represented by Ω / □, but is substantially Ω (sq., □ is dimensionless).
In the present invention, the surface resistance means a numerical value obtained by dividing the potential gradient in the direction parallel to the current flowing along the surface of the test piece by the current per unit width of the surface. This numerical value is defined in JIS K6911-1995 to be equal to the surface resistance between two electrodes having opposite sides of a square of 1 cm on each side as electrodes.

[Transparent conductive layer]
Examples of the transparent conductive layer 21b formed on one surface of the translucent support 21a include those made of indium-tin composite oxide (ITO), fluorine-doped tin oxide (FTO), and the like.

[Method for forming photoelectric conversion layer]
The photoelectric conversion layer 23 of the photoelectrode 20 as described above can be manufactured through the following steps (1) to (5) in this order, as shown in FIG.
(1) A transparent conductive layer 21b is formed on a light transmissive support 21a to obtain a light transmissive substrate 21, and a surface treatment is performed as necessary (see FIG. 2A). .
(2) A paste preparation step for preparing a paste containing semiconductor particles.
(3) A coating film forming step for obtaining a coating film 23A obtained by applying a paste on the transparent conductive layer 21b of the translucent substrate 21 and drying it (see FIG. 2B).
(4) A roll press processing step for obtaining a functional semiconductor layer 23α by performing roll press processing on the coating film 23A formed on the translucent substrate 21 (see FIG. 2C).
(5) A dye carrying step for carrying a sensitizing dye on the functional semiconductor layer 23α (see FIG. 2D).

[Translucent substrate manufacturing process]
The translucent substrate 21 is obtained by forming the transparent conductive layer 21b on the translucent support 21a by, for example, sputtering.
The formation of the transparent conductive layer 21b is preferably performed while performing a heat treatment from the viewpoints of adhesion and durability of the transparent conductive layer 21b to the translucent support 21a.
The temperature of the heat treatment is usually 100 to 150 ° C., for example. However, when the light transmissive support 21 a constituting the light transmissive substrate 21 is made of plastic, the temperature of the heat treatment is the same. The temperature is lower than the heat resistance temperature of the plastic constituting the optical support 21a. Here, the “heat-resistant temperature” means a temperature that is lower of the softening point temperature or the melting point temperature of the plastic.

[Surface treatment of translucent substrate]
The above translucent substrate 21 is formed by combining one or two or more of surface treatments such as ultrasonic cleaning treatment, etching treatment and UV-ozone treatment on the surface thereof, that is, the surface of the transparent conductive layer 21b. The light-transmitting substrate 21 subjected to such a surface treatment may exhibit excellent photoelectric conversion efficiency in the obtained dye-sensitized solar cell.
This is because the surface treatment improves both the wettability when applying the paste on the light-transmitting substrate 21 and the adhesion of the semiconductor particles after the press treatment to the light-transmitting substrate 21. For example, it is confirmed that the contact angle of the surface of the translucent substrate 21 before the surface treatment is larger than 90 °, and the contact angle after the surface treatment is reduced to about 80 to 90 °.
As the surface treatment method of the translucent substrate 21, other treatment methods such as sputtering can be used as appropriate in addition to the ultrasonic cleaning treatment, the etching treatment, and the UV-ozone treatment, and are not limited thereto.

The ultrasonic cleaning treatment uses an ultrasonic cleaner and an ultrasonic cleaning detergent. The translucent substrate is immersed in a container containing a cleaning agent, and the container is placed in an ultrasonic cleaner filled with water. This is a process for cleaning and removing fine deposits and the like on the surface of the translucent substrate by transmitting ultrasonic waves for 10 minutes.
In addition, the etching process is performed by setting a translucent substrate in a high-frequency sputtering apparatus “SVC-700RFII” (manufactured by Sanyu Electronics Co., Ltd.) and setting it to a high vacuum condition (5 Pa), followed by a reverse sputtering (etching) process of 20 W, It is performed under the condition of 10 minutes. Specifically, plasma is generated by applying a high-frequency AC potential, and positively charged argon atoms in the plasma are caused to collide with a negatively charged substrate to remove deposits on the substrate.
Further, the UV-ozone treatment is performed by putting the object to be treated into a UV-ozone cleaning device “OC-2506” (manufactured by Iwasaki Electric Co., Ltd.) and performing ultraviolet irradiation for about 5 minutes.

[Paste preparation process]
The paste used in the production method of the present invention contains semiconductor particles, and can optionally contain a solvent and a binder.
The method for preparing a paste containing a specific group of semiconductor particles constituting the photoelectric conversion layer 23 is not particularly limited. For example, a base that hydrolyzes an alkoxide created by the present inventors with a quaternary ammonium salt. The sex method can be preferably used. Specifically, this basic method is obtained by hydrolyzing an alkoxide for obtaining small semiconductor particles with a quaternary ammonium salt, and similarly obtaining an alkoxide for obtaining large semiconductor particles with a quaternary ammonium salt. And can be prepared by mixing them.
The average particle size of the obtained semiconductor particles can be controlled by adjusting the amount of quaternary ammonium salt to be subjected to hydrolysis, and the average particle size can be increased as the amount of quaternary ammonium salt added is increased. Small semiconductor particles can be obtained.

For example, tetramethylammonium hydroxide (TMAH) can be used as the quaternary ammonium salt, but the methyl group is not limited, and examples include those having an alkyl group having 1 to 4 carbon atoms. it can.
Moreover, as the alkoxide for obtaining the semiconductor large particles, the metal alkoxide constituting the above-described semiconductor particles can be used.
Specifically, for example, when the semiconductor particles are titania particles, Ti (OC ₃ H ₅ ) ₄ can be used as the alkoxide of the semiconductor particles, and TMAH can be used as the quaternary ammonium salt.

  It is preferable that the content rate of the specific semiconductor particle group in a paste is 5-85 mass%, More preferably, it is 5-30 mass%. More preferably, it is 8-20 mass%.

  By using a paste manufactured by a basic method, a paste containing water as a main component of a solvent can be used, and a paste with a small environmental load can be manufactured.

[Coating film forming process]
This step is a step of obtaining a coating film 23A obtained by applying a paste on the transparent conductive layer 21b of the translucent substrate 21 and drying it, and applying the paste on the transparent conductive layer 21b of the translucent substrate 21. There is no restriction | limiting in particular as a method, For example, it can carry out according to well-known various methods, such as a doctor blade method and a spray method.
The drying temperature can be room temperature, for example.
The region where the aqueous paste is applied on the transparent conductive layer 21b functions as a working electrode, and the area of the working electrode region can be appropriately selected depending on the application.
The area of the working electrode that can be produced by the production method of the present invention varies depending on the performance of the roll press used in the roll press treatment step described later, but is, for example, about 20 cm × 20 cm or larger. It is also possible to manufacture a device having a region having a thickness.

[Roll press process]
This step is a step of obtaining a functional semiconductor layer 23α by roll-pressing the coating film 23A. By performing the roll-press treatment, the semiconductor particles in the coating film 23A are sufficiently adhered to each other, and high electron transfer is achieved. Performance.

  By performing the roll press process, a roll press trace extending in parallel to the roll press process direction (including substantially parallel, the same applies hereinafter) is formed on the surface of the functional semiconductor layer 23α. When the roll press trace is generated, the external stress can be relaxed when the photoelectrode for dye-sensitized solar cell is bent or when temporary external stress such as impact is applied, so compared with the case where there is no roll press trace. Thus, the structure can be strong against external stress.

The roll press trace can be visually observed with a scanning electron microscope (SEM). Due to the presence of the roll press trace, on the surface of the functional semiconductor layer 23α, a direction parallel to the roll press treatment direction (first direction) and a direction perpendicular to the first direction (second direction, hereinafter simply The surface roughness Ra is greatly different from that of the “vertical direction”, and the surface roughness Ra in the second direction is 1.2 times or more the surface roughness Ra in the first direction. .
In addition, when using a plane pressing method (not a roll pressing process, a method in which flat plates are aligned vertically and a coating film 23A is sandwiched between them to perform a pressing process), the surface roughness Ra has anisotropy as described above. I don't have it. Therefore, no matter how the first direction is set, the surface roughness Ra in the second direction does not become 1.2 times or more the surface roughness Ra in the first direction. From the viewpoint of stress relaxation as described above, this value is preferably set to 1.25 times or more.

  The surface roughness Ra can be measured using an atomic force microscope (AFM). As for the surface roughness Ra of the functional semiconductor layer 23α, the surface roughness Ra is larger in the direction perpendicular to the roll press processing direction than in the parallel direction. This is mainly due to the mechanism by which a roll press trace is formed. In other words, during the roll press process, the roll contacts the translucent substrate to which a predetermined tension is applied, so that the surface shape of the roll surface is not simply transferred, but the outer peripheral surface of the roll. Slightly moves relative to the functional semiconductor layer. As a result, it is considered that the surface shape of the part of the roll that contacts the functional semiconductor layer is transferred to the surface of the functional semiconductor layer over a predetermined range in the roll press treatment direction.

Also, the roll press process is advantageous compared to the flat press when processing a large area. The flat press reduces the press pressure per unit area due to an increase in area. Therefore, when pressing a large area, it is necessary to increase the pressure in proportion to the area. Is not suitable industrially. However, the roll press treatment is industrially suitable because it is not necessary to increase the pressure applied to the roll even if the area to be produced increases, and a constant force is always required.
Further, by using the roll press process, it becomes possible to produce the photoelectrode at a high speed and reduce the production cost. This contributes to high-speed production and production cost reduction of a dye-sensitized solar cell provided with the photoelectrode.

The roll press treatment is preferably performed within a range of 15 to 35 ° C.
However, the temperature of the roll press treatment is not limited to these, and in order to impart the required physical properties to the functional semiconductor layer, the temperature can be increased from this.
Further, when a solvent is used in the photoelectric conversion layer forming paste, the boiling point of the solvent must be + 50 ° C. or lower. This is because when the processing is performed at a temperature higher than the above temperature, the solvent used is rapidly evaporated and the surface is roughened.
Moreover, when the solvent is not used for the paste for photoelectric conversion formation, it is preferable not to exceed 200 degreeC. This is because if it is processed at a temperature exceeding 200 ° C., the performance of the semiconductor layer is deteriorated, and since plastic is used for the substrate, the substrate is likely to be distorted or the paste used in the roll press process is oxidized. This is because it becomes a factor that inhibits the adhesion between the particles. When the softening point (temperature) or glass transition temperature of the substrate material is lower than 200 ° C., it is necessary to perform the treatment at a temperature lower than that temperature.

And this roll press process WHEREIN: The light transmittance of wavelength 400-800 nm in the laminated body in which the functional semiconductor layer 23 (alpha) was formed on the translucent board | substrate 21 is 105-170% of the value before a roll press process. Preferably it is performed under the conditions of 110 to 170%, particularly preferably 110 to 130%, for example, roll press treatment is preferably performed at a pressure of 40 MPa or more, preferably 100 MPa or more, and 500 MPa or less, It is preferably carried out at a pressure of 150 MPa or less. Thereby, while realizing said light transmittance, the surface roughness of functional semiconductor layer 23 (alpha) can be 50 nm or less, and smoothness can be improved. Also, a roll press trace can be generated at the same time.
When the pressure involved in the roll press process is too high, not only when the plastic substrate is used, but also the translucent support itself of the plastic substrate is distorted and adversely affects the performance of the dye-sensitized solar cell, Furthermore, since the transparent conductive layer formed on the translucent support may be damaged, it is not preferable.
Moreover, it is preferable that the thickness of functional semiconductor layer 23 (alpha) becomes 95 to 30% of the value before roll press processing by performing roll press processing. More preferably, it is 90% to 50%.

[UV-ozone treatment]
After the roll press treatment step and before the next dye supporting step, a UV-ozone treatment can be performed as a surface treatment of the functional semiconductor layer 23α subjected to the roll press treatment, if necessary. This UV-ozone treatment can be performed whether or not the UV-ozone treatment is performed as the surface treatment of the translucent substrate 21.
By performing this UV-ozone treatment, not only the surface of the semiconductor particles constituting the functional semiconductor layer 23α can be cleaned, but also the hydrophilic groups of the semiconductor particles are increased so that the sensitizing dye is easily adsorbed. As a result, the resulting dye-sensitized solar cell can have high photoelectric conversion efficiency.
In addition, when using a method in which TMAH used for the production of titania particles remains in the functional semiconductor layer 23α as an unreacted substance, such as a basic method, in the paste preparation step, this TMAH is treated by UV-ozone treatment. The semiconductor particles can be surface-cleaned by decomposition. This UV-ozone treatment can be performed in the same manner as the UV-ozone treatment for the translucent substrate 21.

(Dye support process)
The method for supporting the sensitizing dye on the functional semiconductor layer 23α of the photoelectrode structure 20K is not particularly limited. For example, the sensitizing dye is an alcohol, nitrile, nitromethane, halogenated hydrocarbon, ether, dimethyl sulfoxide, Soluble in solvents such as amides, N-methylpyrrolidone, 1,3-dimethylimidazolidinone, 3-methyloxazolidinone, esters, carbonates, ketones, hydrocarbons, water, etc., or a mixture of two or more of these In addition, a dipping method, a spray coating method, a printing coating method, or the like, in which the photoelectrode structure 20K on which the functional semiconductor layer 23α is formed is dipped, can be used.

  The dye-sensitized solar cell using the photoelectrode for dye-sensitized solar cell obtained by the manufacturing method as described above can have high photoelectric conversion efficiency even if the translucent support is made of plastic. This is presumed to be because the semiconductor particles are somewhat pressed into the transparent conductive layer by pressurizing the semiconductor particles on a soft plastic translucent support, and a closer bond can be obtained. In the case of a light-transmitting support made of a hard material, since it does not have such elasticity, it is presumed that the performance is lower than that using a plastic light-transmitting support.

[Electrolyte part]
In the dye-sensitized solar cell of the present invention, the electrolyte portion 12 interposed between the photoelectrode 20 and the counter electrode 16 may be in a liquid state, a solid state, a solidified body state, or a room temperature molten salt state. Good.
Further, the thickness of the electrolyte portion 12, that is, the separation distance between the photoelectrode 20 and the counter electrode 16 is, for example, 1 to 100 μm.

When the electrolyte part 12 is, for example, in the form of a solution, the electrolyte part 12 is preferably composed of an electrolyte, a solvent, and an additive.
As electrolytes, combinations of metal iodides such as lithium iodide, sodium iodide, potassium iodide, cesium iodide and iodine, and quaternary ammonium such as tetraalkylammonium iodide, pyridinium iodide, imidazolium iodide, etc. A combination of an iodine salt of the compound and iodine, or a combination of bromine compound and bromine instead of the iodine or iodine compound, or a combination of cobalt complex may be used. When the electrolyte is an ionic liquid, it is not necessary to use a solvent. The electrolyte may be a gel electrolyte, a polymer electrolyte, or a solid electrolyte, and an organic charge transport material may be used instead of the electrolyte.

  Examples of the solvent in the case where the electrolyte portion 12 is in the form of a solution include nitrile solvents such as acetonitrile, methoxyacetonitrile, propionitrile, carbonate solvents such as ethylene carbonate, ether solvents, alcohol solvents, and the like. Can be mentioned.

  When the electrolyte portion 12 is in the form of a solution, the concentration of the electrolyte in the electrolyte solution varies depending on the type of the electrolyte. For example, when the electrolyte is an iodine salt-iodine combination, It is preferable that it is 0.1 to 1.0M.

[Counter electrode]
The counter electrode 16 functions as a positive electrode of the photoelectric conversion element 10, and a substance having a function of reducing an electrolyte, for example, a metal such as platinum, a conductive polymer, carbon, or the like, is oxidized with a conductive metal oxide such as ITO or FTO. It can be formed by carrying it on a substrate made of a material or metal. The counter electrode 16 may be generally configured by providing a conductive film made of the above metal, carbon, or conductive polymer on a conductive support or a support having the same conductive layer. However, it is not essential to have a support if sufficient strength and sealability can be obtained.

[Method for producing photoelectric conversion element]
In the photoelectric conversion element 10 described above, for example, when the electrolyte portion 12 is in a liquid state, the photoelectrode 20 and the counter electrode 16 are disposed to face each other via an appropriate spacer, and the electrolyte portion is interposed between the photoelectrode 20 and the counter electrode 16. By encapsulating 12, the photoelectric conversion element 10 constituting the dye-sensitized solar cell is obtained.
The above photoelectric conversion element 10 can be produced in various shapes depending on the application, and the shape is not particularly limited.

Photoelectric conversion in the dye-sensitized solar cell is performed as follows.
First, sunlight incident through the light-transmitting substrate 21 of the photoelectrode 20 is absorbed by the ground-state sensitizing dye supported on the surface of the semiconductor particles of the photoelectric conversion layer 23, and this sensitizing dye is excited. And electrons are generated. The electrons are injected into the semiconductor particles, and the electrons injected into the semiconductor particles are diffused through the photoelectric conversion layer 23 and guided to the counter electrode 16 through the transparent conductive layer 21 b and the connection 17. On the other hand, the sensitizing dye that has lost the electrons receives electrons from the electrolyte portion 12 and returns to the ground state. Then, the electrolyte portion 12 oxidized by passing the electrons receives the electrons from the counter electrode 16 and is reduced to return to the basic state. Through the above series of processes, an electromotive force is generated between the translucent substrate 21 electrically connected to the photoelectric conversion layer 23 and the counter electrode 16.

  According to the dye-sensitized solar cell including the photoelectric conversion element 10 described above, when two or more kinds of semiconductor particles having different specific average particle diameters are used for the photoelectric conversion layer 23 of the photoelectrode 20 for the dye-sensitized solar cell. The sensitizing dye contained in the photoelectric conversion layer 23 can achieve high light absorption efficiency due to the so-called light confinement effect, and by forming the photoelectric conversion layer 23 using a paste by a specific method, Even if the translucent support 21a of the translucent substrate 21 is made of any material, that is, for example, when a plastic substrate that has conventionally been difficult to obtain high light absorption efficiency is used. The photoelectric conversion layer 23 can be formed on the translucent substrate 21 with high adhesion. As a result, even when a plastic substrate is used, a high level can be obtained even when the amount of incident light is changed. It can be maintained in the photoelectric conversion efficiency.

[Modification]
Various changes can be made in the above photoelectric conversion element.
For example, as shown in FIG. 3, a light scattering layer 25 made only of large semiconductor particles may be formed on the surface of the photoelectric conversion layer 23. The light scattering layer 25 of the photoelectric conversion element 10A may be made of, for example, a paste coating film containing large semiconductor particles without using a binder and an organic solvent using water as a solvent.
The thickness of the light scattering layer 25 can be set to 1 to 15 μm, for example.
According to the photoelectric conversion element 10A having the dye-sensitized solar cell photoelectrode 20A formed with such a light scattering layer 25, an extremely high light confinement effect can be obtained, and as a result, an extremely high photoelectric conversion efficiency. Thus, a dye-sensitized solar cell in which is achieved can be configured.

In addition, for example, the photoelectrode for dye-sensitized solar cell constituting the photoelectric conversion element described above has a photoelectric conversion layer that does not contain a binder and an organic solvent, and sensitizes a coating film of a paste containing a specific group of semiconductor particles. It may be composed of a pressure-sensitive semiconductor layer carrying a sensitizing dye obtained by carrying out a roll press treatment after carrying a dye.
The photoelectrode for dye-sensitized solar cell of this example is obtained by carrying out roll press treatment after carrying the sensitizing dye on the coating film of the paste. Since the sensitizing dye is peeled off, the dye sensitization obtained in comparison with the photoelectrode 20 in the first embodiment, which is produced by carrying the roll press treatment of the paste coating and supporting the sensitizing dye, is performed. The performance of the solar cell is low.

<Second Embodiment>
The photoelectrode for dye-sensitized solar cell constituting the dye-sensitized solar cell in this example is specified on the layer obtained by roll-pressing the paste coating film with the functional semiconductor layer constituting the photoelectric conversion layer. The structure is the same as that of the first embodiment except that the semiconductor particle group is a multilayer structure in which one or more layers made of a coating film of a paste not containing a binder and an organic solvent are formed. is there.

Specifically, this photoelectric conversion layer 26 (see FIG. 4C) is obtained by applying a paste containing a specific group of semiconductor particles obtained in the same manner as the functional semiconductor layer 23α in the first embodiment. One or more layers of a coating film 23C (see FIG. 4B) of a paste containing a specific semiconductor particle group are formed on a layer 23B (see FIG. 4A) obtained by roll-pressing the film. A sensitizing dye is supported on the functional semiconductor layer 23β.
The coating film 23C of paste can be laminated in 1 to 3 layers.
Moreover, the kind and content ratio of the specific semiconductor particle group contained in the paste for forming the coating film 23C of this paste are the same as the paste for forming the layer 23B obtained by roll-pressing the coating film. It may be the same as or different from the kind and content ratio of the specific semiconductor particle group contained.

  In the photoelectric conversion element of this example, the layer thickness of the layer 23B obtained by roll-pressing the coating film is, for example, 1 to 20 μm, and the layer thickness of the coating film 23C of one layer of paste is, for example, 1 to 15 μm. The

  As a manufacturing method of this dye-sensitized solar cell photoelectrode, as shown in FIGS. 4A to 4C, the photoelectrode structure 20K formed in the first embodiment, that is, translucent support, is used. A photoconductive electrode structure 20L in which a coating film 23C of paste is formed is formed on the layer 23B in which a transparent conductive layer 21b and a layer 23B obtained by pressing the coating film are formed in this order on the body 21a. In addition, the functional semiconductor layer 23β in the photoelectrode structure 20L may be loaded with a sensitizing dye by the method described above. Specifically, after the roll press treatment process (4) of the manufacturing process in the first embodiment, 1 to 3 layers of the coating film 23C of the paste are formed, and then the dye carrying process (5) is performed.

  The roll press process performed in the state which formed the said coating film for obtaining the layer 23B obtained by roll-pressing a coating film on the translucent board | substrate 21 is the same as the roll press process in 1st Embodiment. Can be performed under the following conditions. That is, in the roll press treatment, the light transmittance at a wavelength of 400 to 800 nm in the laminate in which the layer 23B obtained by roll press treatment of the coating film on the translucent substrate 21 is the value before the roll press treatment. It is preferable to carry out under the conditions of 105 to 170%, more preferably 110 to 170%, particularly preferably 110 to 130%.

If the pressure involved in the roll press treatment is too high, the translucent support itself is distorted, particularly when a plastic translucent support is used, not only adversely affecting the performance of the dye-sensitized solar cell. Furthermore, since the transparent conductive layer formed on the translucent support may be damaged, it is not preferable.
Moreover, by performing this roll press process, the thickness of the layer 23B obtained by performing the roll press process on the coating film constituting the functional semiconductor layer 23β is 80 to 30% of the value before the roll press process. Is preferred.

In addition, the first embodiment is applied as a surface treatment of the functional semiconductor layer 23β, if necessary, after laminating the coating film 23C of the paste after the roll press treatment step and before the next dye supporting step. The UV-ozone treatment can be performed by the same method as in the above. This UV-ozone treatment can be performed whether or not the UV-ozone treatment is performed as the surface treatment of the translucent substrate 21.
By performing this UV-ozone treatment, not only the surface of the semiconductor particles constituting the functional semiconductor layer 23β can be cleaned, but also the hydrophilic groups of the semiconductor particles are increased so that the sensitizing dye is easily adsorbed. As a result, the resulting dye-sensitized solar cell can have high photoelectric conversion efficiency.
In the paste preparation process, when TMAH used for producing titania particles such as a basic method remains in the functional semiconductor layer 23β as an unreacted substance, this TMAH is decomposed by UV-ozone treatment. Thus, the surface of the semiconductor particles can be cleaned.

According to the photoelectrode for a dye-sensitized solar cell including the photoelectric conversion element 10A of this example, the same effect as that of the photoelectric conversion element 10 in the first embodiment can be obtained.
Furthermore, the functional semiconductor layer 23β includes the layer 23B that has been roll-pressed and the layer 23C that is formed on the layer 23B, thereby further improving the battery performance while improving the adhesion to the translucent support. Can be improved.

Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto.
[Example 1]
(Preparation of titania semiconductor particle suspension)
Tetraisopropyl orthotitanate (56.8 g) was dropped into 200 mL of ion-exchanged water with good stirring, and after completion of the dropping, the stirring was further continued for 1 hour to complete the hydrolysis, and the target titanium hydroxide precipitate was obtained. Got. The precipitate was filtered off using filter paper and washed thoroughly with ion exchange water.
This precipitate was added to ion-exchanged water in which 5.8 g of tetramethylammonium hydroxide (TMAH) was dissolved, and ion-exchanged water was further added to make the total amount of the sample 160 g.
This sample was heated to reflux at 140 ° C. for 4 hours, and then the microcrystal was removed with a glass filter to obtain a cloudy translucent colloidal solution.
The resulting colloidal solution is transferred to a sealed autoclave container and hydrothermal synthesis is performed at 260 ° C. for 8 hours. After this hydrothermal synthesis, the solvent of the colloidal solution is replaced with ethanol using an evaporator, and then ultrasonic dispersion treatment is performed. Then, an ethanol suspension [A] containing anatase crystal-type titania particles [A] having an average particle diameter of 20 nm was obtained (the above operation is referred to as “semiconductor particle suspension preparation operation”).
The trimethylamine produced by the decomposition of TMAH is almost completely removed during the operation of replacing the solvent of the colloidal solution with ethanol.

In the operation of preparing the semiconductor particle suspension, an ethanol suspension containing anatase crystal-type titania particles [B] having an average particle diameter of 100 nm is used except that the amount of TMAH added is 1.5 g. B] was obtained.
For titania particles contained in ethanol suspensions [A] and [B], the ethanol suspension was applied on a slide glass by a doctor blade method and dried, then the XRD pattern was measured, and the obtained XRD pattern The half width was obtained from the above, and the average particle diameter was calculated by using the Scherrer equation (D = K × λ / βcos θ), and the crystal form of the titania particles was confirmed. However, in the formula, D is the length of the crystallite, β is the half width, θ is the diffraction angle, K = 0.94, and λ = 1.5418.
The titania particles [A] and titania particles [B] were almost 100% anatase crystal form, and the presence of the rutile crystal form was not confirmed.
The Scherrer equation has a large error when the average particle diameter exceeds 50 nm. Therefore, when the average particle diameter exceeds 50 nm, the following method was used. That is, an ethanol suspension was applied onto a slide glass by a doctor blade method and dried, then imaged using an SEM, and an average particle diameter was obtained by taking a calculated average of particle radii obtained in the image.

(Preparation of aqueous paste for photoelectric conversion layer formation)
For these two types of ethanol suspensions [A] and [B], the concentration of each titania particle is first measured by the weight (W) of the crucible with an electronic balance, and then the ethanol suspension is taken into the crucible. , Weigh the total mass (W1) of the crucible and the ethanol suspension, put it in an electric furnace and hold at 150 ° C. for 2 hours to completely remove the solvent of the ethanol suspension, and then again mass ( W2) was weighed and calculated from the formula {concentration of titania particles (wt%) = (W2-W) / (W1-W) × 100}.
Then, based on the respective concentrations, the titania particles [A] and the titania particles [B] are mixed so that the weight ratio is 7: 3, and this mixed solution is again almost completely watered using an evaporator. By substituting and concentrating, a photoelectric conversion layer forming paste [1] having a titania particle concentration of 10 wt% and water as a medium was finally obtained.

A translucent substrate made of an ITO / PEN (polyethylene naphthalate) substrate (manufactured by Oji Tobi) having a sheet resistance of 13 Ω / □ (Ω / cm ² ) is obtained from the aqueous paste [1] for forming a photoelectric conversion layer by a doctor blade method. In addition, after applying to a working electrode region of 0.5 cm × 0.5 cm in size, it was dried at room temperature to obtain a coating film, a metal roll was used for the roll press treatment, A roll press was used. Using a roll press machine, a roll press treatment with a predetermined press pressure and a diameter of 25 cm was performed at 1 rpm. The pressure of the roll press adjusted the clearance, and the pressure was confirmed using a pressure-sensitive film (“Prescale, manufactured by Fuji Film Co., Ltd.”). In addition, the pressure sensitive film was arrange | positioned on the board | substrate surface in which the titania coating film is not formed. The press pressure was set while adjusting the roll clearance and confirming the actual press load with a pressure sensitive film. This paste was roll-pressed from both sides at a pressure of 100 MPa to obtain a photoelectrode structure in which a functional semiconductor layer was formed on a translucent substrate.

  By performing this roll press treatment, the light transmittance at a wavelength of 400 to 800 nm in the functional semiconductor layer is increased by 110% with respect to the value before the roll press treatment, and the layer thickness is reduced to 70%, which is 6 μm. It was. The cell effective area was corrected with four significant figures using a digital microscope and a calibration scale. The measurement result of the transmittance of this photoelectrode structure at a wavelength of 200 to 900 nm was performed on the samples before and after the roll press treatment. The transmittance measurement was performed using U-4000 (manufactured by Hitachi High-Technologies Corporation). The film thickness was measured using a stylus type surface shape measuring device DEKTAK (manufactured by ULVAC).

After the roll press treatment, a 1,000 times and 20,000 times SEM photograph of the coating film formed on the substrate was observed, and as shown in FIG. 5, a roll press trace extending in parallel with the roll press treatment direction was confirmed.
Furthermore, the film thickness of the functional semiconductor layer before and after the roll press treatment was measured, and the surface roughness Ra of the functional semiconductor layer was measured using an atomic force microscope (AFM). The measurement procedure is as follows.
First, a square region having a side of 10 μm on the surface of the functional semiconductor layer is measured by AFM. At this time, the roll press processing direction and one side of the square region are made parallel or substantially parallel.
As shown in FIG. 7, the square region 300 extends in the roll press direction and is divided into strip regions 310, 320, and 330 each having a width of 3 μm, 4 μm, and 3 μm, and the AFM is formed in each of the strip regions 310, 320, and 330. Use to calculate the surface roughness Ra. The value obtained by summing the values of the obtained surface roughness Ra and dividing by 3 is defined as the surface roughness Ra in the first direction.
Next, as shown in FIG. 8, the square region 300 extends in a direction orthogonal to the roll press direction and is divided into strip regions 410, 420, and 430 having a width of 3 μm, 4 μm, and 3 μm, respectively. At 420 and 430, the surface roughness Ra is calculated using AFM. The value obtained by summing the values of the obtained surface roughness Ra and dividing by 3 is defined as the surface roughness Ra in the second direction.
Then, the surface roughness ratio was calculated by dividing the surface roughness Ra in the second direction by the surface roughness Ra in the first direction.
As a result, the surface roughness ratio was 35.0 nm / 19.3 nm = 1.81, and anisotropy of the surface roughness Ra was confirmed in the second direction and the first direction.
In addition, the definition of surface roughness Ra in this invention is Img. Conforms to Ra.

(Supporting sensitizing dyes and production of photoelectrodes)
On the other hand, cis-bis (isothiocyanato) -bis (2,2′-dipyridyl-4,4′-dicarboxylic acid) -ruthenium (II) bis-tetrabutylammonium was used as the sensitizing dye, and was added to the ethanol in an amount of 0. A dye solution is obtained by dissolving at a concentration of 2 mM, and the photoelectrode structure on which the functional semiconductor layer is formed is immersed in the dye solution for 24 hours, and light in which the sensitizing dye is supported on the functional semiconductor layer. An electrode [1] was obtained.
In addition, when this SEM observation was performed similarly to the above about this photoelectrode [1], the roll press trace confirmed in the SEM observation after a roll press process was observed similarly.

(Preparation of dye-sensitized solar cell)
As the electrolyte solution, an acetonitrile solution in which iodine, lithium iodide, 1,2-dimethyl-3-propylimidazolium iodide and t-butylpyridine were dissolved was used. These were dissolved in acetonitrile under a nitrogen atmosphere to be 0.05M, 0.1M, 0.6M and 0.5M, respectively.
As a counter electrode, a Ti plate having a thickness of 100 μm and platinum deposited thereon was used.
The above-described photoelectrode [1] is combined with an insulating spacer having a thickness of 50 μm and a counter electrode in this order, and an electrolyte solution is injected between the photoelectrode [1] and the counter electrode with a microsyringe, whereby a dye-sensitized solar cell [1] ] Was produced.

(Performance evaluation of dye-sensitized solar cells)
This dye-sensitized solar cell [1] is irradiated with simulated sunlight of AM1.5, 100 mW / cm ² using a “solar simulator” (Peccell), “2400 type source meter” (manufactured by KEITHLEY) ) Were used to measure the IV characteristics to obtain the values of the short circuit current, the open circuit voltage, and the shape factor ff, and the photoelectric conversion efficiency was calculated by the following formula (1) using these values.
Formula (1); photoelectric conversion efficiency (%) = [short circuit current value (mA / cm ² ) × open circuit voltage value (V) × {form factor ff / incident light (100 mW / cm ² )}] × 100

[Example 2]
A dye-sensitized solar cell [2] was obtained in the same manner as in Example 1 except that a paste containing only titania particles [A] was used, and this dye-sensitized solar cell [2] was short-circuited in the same manner as in Example 1. The values of open circuit voltage, form factor ff, and photoelectric conversion efficiency were obtained.
At this time, the obtained functional semiconductor layer was subjected to surface observation using SEM, and a roll press trace extending in parallel with the roll press treatment direction was confirmed.
Further, the surface roughness Ra was measured in the same procedure as in Example 1, and the transmittance with respect to the wavelength and the film thickness before and after the press treatment in the functional semiconductor were measured.
As a result of measuring the surface roughness Ra, the surface roughness ratio is 34.1 nm / 17.5 nm = 1.95, and the anisotropy of the surface roughness Ra was confirmed in the second direction and the first direction. It was.

Example 3
A dye-sensitized solar cell [3] was obtained in the same manner as in Example 1 except that a paste in which titania particles [A] and titania particles [B] were mixed so that the weight ratio was 6: 4 was used. For the sensitized solar cell [3], the values of short-circuit current, open-circuit voltage, form factor ff, and photoelectric conversion efficiency were obtained in the same manner as in Example 1.
At this time, the obtained functional semiconductor layer was subjected to surface observation using SEM, and a roll press trace extending in parallel with the roll press treatment direction was confirmed.
Further, the surface roughness Ra was measured in the same procedure as in Example 1, and the transmittance with respect to the wavelength and the film thickness before and after the press treatment in the functional semiconductor were measured.
As a result of measuring the surface roughness Ra, the surface roughness ratio is 13.7 nm / 9.0 nm = 1.52, and the anisotropy of the surface roughness Ra is confirmed in the second direction and the first direction. It was.

Example 4
A dye-sensitized solar cell [4] was obtained in the same manner as in Example 1 except that ITO / PET was used instead of the ITO / PEN substrate, and this dye-sensitized solar cell [4] was the same as in Example 1. Thus, values of short-circuit current, open-circuit voltage, form factor ff, and photoelectric conversion efficiency were obtained.
At this time, the obtained functional semiconductor layer was subjected to surface observation using SEM, and a roll press trace extending in parallel with the roll press treatment direction was confirmed.
Further, the surface roughness Ra was measured in the same procedure as in Example 1, and the transmittance with respect to the wavelength and the film thickness before and after the press treatment in the functional semiconductor were measured.
As a result of the surface roughness Ra measurement, the surface roughness ratio is 23.9 nm / 18.8 nm = 1.27, and the anisotropy of the surface roughness Ra was confirmed in the second direction and the first direction. It was.

Example 5
A dye-sensitized solar cell [5] was obtained in the same manner as in Example 1 except that the working electrode region was 0.5 cm × 4.5 cm. This dye-sensitized solar cell [5] was the same as in Example 1. Thus, values of short-circuit current, open-circuit voltage, form factor ff, and photoelectric conversion efficiency were obtained.
At this time, the obtained functional semiconductor layer was subjected to surface observation using SEM, and a roll press trace extending in parallel with the roll press treatment direction was confirmed.
Further, the surface roughness Ra was measured in the same procedure as in Example 1, and the transmittance with respect to the wavelength and the film thickness before and after the press treatment in the functional semiconductor were measured.
As a result of measuring the surface roughness Ra, the surface roughness ratio is 25.5 nm / 16.6 nm = 1.54, and the anisotropy of the surface roughness Ra was confirmed in the second direction and the first direction. It was.

Example 6
A dye-sensitized solar cell [6] was obtained in the same manner as in Example 1 except that a commercially available paste “PECC-K01” (manufactured by Pexel) was used as the paste. About this dye-sensitized solar cell [6] In the same manner as in Example 1, values of short circuit current, open circuit voltage, form factor ff, and photoelectric conversion efficiency were obtained.
At this time, the obtained functional semiconductor layer was subjected to surface observation using SEM, and a roll press trace extending in parallel with the roll press treatment direction was confirmed.
Further, the surface roughness Ra was measured in the same procedure as in Example 1, and the transmittance with respect to the wavelength and the film thickness before and after the press treatment in the functional semiconductor were measured.
As a result of measuring the surface roughness Ra, the surface roughness ratio is 30.0 nm / 16.4 nm = 1.83, and the anisotropy of the surface roughness Ra is confirmed in the second direction and the first direction. It was.
The data of Examples 1 to 6 are shown in Table 1.

[Comparative Example A-1]
Instead of the roll press treatment, Mini Test Press-10 (manufactured by Toyo Seiki) was used for the flat press treatment. 5mm Cornex felt (manufactured by DuPont), pressure-sensitive film ("Prescale", manufactured by Fuji Film), translucent substrate, fluorine release film, and 5mm Cornex felt (manufactured by DuPont) Laminates were sequentially laminated to obtain a layered structure of “Conex felt” / “Pressure sensitive film” / “Fluorine release film” / Titania-coated ITO-PEN substrate / “Conex felt”. This laminate was pressed for 60 seconds while confirming the actual press load with a pressure-sensitive film. The load at this time was a pressure of 100 MPa.
A comparative dye-sensitized solar cell [A-1] was obtained in the same manner as in Example 1 except that flat press processing was performed instead of roll press processing, and this comparative dye-sensitized solar cell [A-1] In the same manner as in Example 1, values of short circuit current, open circuit voltage, form factor ff, and photoelectric conversion efficiency were obtained. At this time, when the surface of the obtained functional semiconductor layer was observed using an SEM, a trace extending in a specific direction like a roll press trace was recognized as in the enlarged photograph shown in FIG. There wasn't. Moreover, the transmittance | permeability with respect to the wavelength in a functional semiconductor and the film thickness before and behind a press process were measured.

[Comparative Example A-2]
Instead of the roll press treatment, Mini Test Press-10 (manufactured by Toyo Seiki) was used for the flat press treatment. 5mm Cornex felt (manufactured by DuPont), pressure-sensitive film ("Prescale", manufactured by Fuji Film), translucent substrate, fluorine release film, and 5mm Cornex felt (manufactured by DuPont) Laminates were sequentially laminated to obtain a layered structure of “Conex felt” / “Pressure sensitive film” / “Fluorine release film” / Titania-coated ITO-PEN substrate / “Conex felt”. This laminate was pressed for 60 seconds while confirming the actual press load with a pressure-sensitive film. The load at this time was a pressure of 100 MPa.
A comparative dye-sensitized solar cell [A-2] was obtained in the same manner as in Example 2 except that flat press processing was performed instead of roll press processing, and this comparative dye-sensitized solar cell [A-2] -2] were obtained in the same manner as in Example 2 to obtain values of short-circuit current, open-circuit voltage, form factor ff, and photoelectric conversion efficiency. Under the present circumstances, when the surface observation was performed using SEM with respect to the obtained functional semiconductor layer, the trace extended in a specific direction like the roll press trace was not recognized. Moreover, the transmittance | permeability with respect to the wavelength in a functional semiconductor and the film thickness before and behind a press process were measured.

[Comparative Example A-3]
Instead of the roll press treatment, Mini Test Press-10 (manufactured by Toyo Seiki) was used for the flat press treatment. 5mm Cornex felt (manufactured by DuPont), pressure-sensitive film ("Prescale", manufactured by Fuji Film), translucent substrate, fluorine release film, and 5mm Cornex felt (manufactured by DuPont) Laminates were sequentially laminated to obtain a layered structure of “Conex felt” / “Pressure sensitive film” / “Fluorine release film” / Titania-coated ITO-PEN substrate / “Conex felt”. This laminate was pressed for 60 seconds while confirming the actual press load with a pressure-sensitive film. The load at this time was a pressure of 100 MPa.
A comparative dye-sensitized solar cell [A-3] was obtained in the same manner as in Example 2 except that flat press processing was performed instead of roll press processing, and this comparative dye-sensitized solar cell [A-3] −3] were obtained in the same manner as in Example 3 to obtain values of short-circuit current, open-circuit voltage, form factor ff, and photoelectric conversion efficiency. Under the present circumstances, when the surface observation was performed using SEM with respect to the obtained functional semiconductor layer, the trace extended in a specific direction like the roll press trace was not recognized. Moreover, the transmittance | permeability with respect to the wavelength in a functional semiconductor and the film thickness before and behind a press process were measured.

[Comparative Example A-4]
Instead of the roll press treatment, Mini Test Press-10 (manufactured by Toyo Seiki) was used for the flat press treatment. 5mm Cornex felt (manufactured by DuPont), pressure-sensitive film ("Prescale", manufactured by Fuji Film), translucent substrate, fluorine release film, and 5mm Cornex felt (manufactured by DuPont) Laminates were sequentially laminated to obtain a layered structure of “Conex felt” / “Pressure sensitive film” / “Fluorine release film” / Titania-coated ITO-PEN substrate / “Conex felt”. This laminate was pressed for 60 seconds while confirming the actual press load with a pressure-sensitive film. The load at this time was a pressure of 100 MPa.
A comparative dye-sensitized solar cell [A-4] was obtained in the same manner as in Example 4 except that flat press processing was performed instead of roll press processing, and this comparative dye-sensitized solar cell [A-4] -4] was obtained in the same manner as in Example 4 to obtain values of short-circuit current, open-circuit voltage, form factor ff, and photoelectric conversion efficiency. Under the present circumstances, when the surface observation was performed using SEM with respect to the obtained functional semiconductor layer, the trace extended in a specific direction like the roll press trace was not recognized. Moreover, the transmittance | permeability with respect to the wavelength in a functional semiconductor and the film thickness before and behind a press process were measured.
[Comparative Example A-5]
Instead of the roll press treatment, Mini Test Press-10 (manufactured by Toyo Seiki) was used for the flat press treatment. 5mm Cornex felt (manufactured by DuPont), pressure-sensitive film ("Prescale", manufactured by Fuji Film), translucent substrate, fluorine release film, and 5mm Cornex felt (manufactured by DuPont) Laminates were sequentially laminated to obtain a layered structure of “Conex felt” / “Pressure sensitive film” / “Fluorine release film” / Titania-coated ITO-PEN substrate / “Conex felt”. This laminate was pressed for 60 seconds while confirming the actual press load with a pressure-sensitive film. The load at this time was a pressure of 100 MPa.
A comparative dye-sensitized solar cell [A-5] was obtained in the same manner as in Example 5 except that flat press processing was performed instead of roll press processing, and this comparative dye-sensitized solar cell [A-5] −5] In the same manner as in Example 5, values of short-circuit current, open-circuit voltage, form factor ff, and photoelectric conversion efficiency were obtained. Under the present circumstances, when the surface observation was performed using SEM with respect to the obtained functional semiconductor layer, the trace extended in a specific direction like the roll press trace was not recognized. Moreover, the transmittance | permeability with respect to the wavelength in a functional semiconductor and the film thickness before and behind a press process were measured.

[Comparative Example A-6]
Instead of the roll press treatment, Mini Test Press-10 (manufactured by Toyo Seiki) was used for the flat press treatment. 5mm Cornex felt (manufactured by DuPont), pressure-sensitive film ("Prescale", manufactured by Fuji Film), translucent substrate, fluorine release film, and 5mm Cornex felt (manufactured by DuPont) Laminates were sequentially laminated to obtain a layered structure of “Conex felt” / “Pressure sensitive film” / “Fluorine release film” / Titania-coated ITO-PEN substrate / “Conex felt”. This laminate was pressed for 60 seconds while confirming the actual press load with a pressure-sensitive film. The load at this time was a pressure of 100 MPa.
A comparative dye-sensitized solar cell [A-6] was obtained in the same manner as in Example 6 except that flat press processing was performed instead of roll press processing, and this comparative dye-sensitized solar cell [A-6] −6] In the same manner as in Example 6, values of short-circuit current, open-circuit voltage, form factor ff, and photoelectric conversion efficiency were obtained. Under the present circumstances, when the surface observation was performed using SEM with respect to the obtained functional semiconductor layer, the trace extended in a specific direction like the roll press trace was not recognized. Moreover, the transmittance | permeability with respect to the wavelength in a functional semiconductor and the film thickness before and behind a press process were measured.
The data of Comparative Examples A-1 to A-6 are shown in Table 2.

[Comparative Example C-1]
A comparative dye-sensitized solar cell [C-1] was obtained in the same manner as in Example 1 except that the coating film was not subjected to roll press treatment and heated at 150 ° C. for 10 minutes. For this comparative dye-sensitized solar cell [C-1], the values of short-circuit current, open-circuit voltage, form factor ff, and photoelectric conversion efficiency were obtained in the same manner as in Example 1. Under the present circumstances, when the surface observation was performed using SEM with respect to the obtained functional semiconductor layer, the trace extended in a specific direction like the roll press trace was not recognized. Further, the surface roughness Ra was measured in the same procedure as in Example 1, and the transmittance and film thickness with respect to the wavelength in the functional semiconductor were measured. However, in the measurement of the surface roughness Ra, since the roll press process was not performed, the square region was set at an arbitrary position, and the direction in which the measured value of the surface roughness Ra was smaller was set as the first direction.
As a result of measuring the surface roughness Ra, the surface roughness ratio is 45.0 nm / 42.4 nm = 1.06, and anisotropy of the surface roughness Ra is recognized between the second direction and the first direction. There wasn't.

[Comparative Example C-2]
A comparative dye-sensitized solar cell [C-2] was obtained in the same manner as in Example 2 except that the coating film was not roll-pressed and heated at 150 ° C. for 10 minutes. For this comparative dye-sensitized solar cell [C-2], the values of short-circuit current, open-circuit voltage, form factor ff, and photoelectric conversion efficiency were obtained in the same manner as in Example 1. Under the present circumstances, when the surface observation was performed using SEM with respect to the obtained functional semiconductor layer, the trace extended in a specific direction like the roll press trace was not recognized. Further, the surface roughness Ra was measured in the same procedure as in Comparative Example C-1, and the transmittance and film thickness with respect to the wavelength in the functional semiconductor were measured.
As a result of measuring the surface roughness Ra, the surface roughness ratio is 45.3 nm / 43.0 nm = 1.05, and anisotropy of the surface roughness Ra is recognized between the second direction and the first direction. There wasn't.

[Comparative Example C-3]
A comparative dye-sensitized solar cell [C-3] was obtained in the same manner as in Example 6 except that the coating film was not subjected to roll press treatment and heated at 150 ° C. for 10 minutes. For this comparative dye-sensitized solar cell [C-3], the values of short-circuit current, open-circuit voltage, form factor ff, and photoelectric conversion efficiency were obtained in the same manner as in Example 1. Under the present circumstances, when the surface observation was performed using SEM with respect to the obtained functional semiconductor layer, the trace extended in a specific direction like the roll press trace was not recognized. Moreover, the transmittance | permeability with respect to the wavelength and film thickness in a functional semiconductor were measured.
Table 3 shows data of Comparative Examples C-1 to C-3.

[Comparative Example D-1]
A comparative dye-sensitized solar cell [D-1] was obtained in the same manner as in Example 1 except that the coating film was not subjected to press treatment and heat treatment and held at room temperature for 10 minutes. About the sensitized solar cell [D-1], it carried out similarly to Example 1, and obtained the value of the short circuit current, the open circuit voltage, the shape factor ff, and the photoelectric conversion efficiency. Under the present circumstances, when the surface observation was performed using SEM with respect to the obtained functional semiconductor layer, the trace extended in a specific direction like the roll press trace was not recognized. Moreover, the transmittance | permeability with respect to the wavelength and film thickness in a functional semiconductor were measured.

[Comparative Example D-2]
A comparative dye-sensitized solar cell [D-2] was obtained in the same manner as in Example 2 except that the coating film was not pressed and heated for 10 minutes at room temperature, and this comparative dye was obtained. About the sensitized solar cell [D-2], it carried out similarly to Example 2, and obtained the value of the short circuit current, the open circuit voltage, the shape factor ff, and the photoelectric conversion efficiency. Under the present circumstances, when the surface observation was performed using SEM with respect to the obtained functional semiconductor layer, the trace extended in a specific direction like the roll press trace was not recognized. Moreover, the transmittance | permeability with respect to the wavelength and film thickness in a functional semiconductor were measured.

[Comparative Example D-3]
A comparative dye-sensitized solar cell [D-3] was obtained in the same manner as in Example 6 except that the coating film was not subjected to press treatment and heat treatment and held at room temperature for 10 minutes. About the sensitized solar cell [D-3], it carried out similarly to Example 6, and obtained the value of the short circuit current, the open circuit voltage, the shape factor ff, and the photoelectric conversion efficiency. Under the present circumstances, when the surface observation was performed using SEM with respect to the obtained functional semiconductor layer, the trace extended in a specific direction like the roll press trace was not recognized. Moreover, the transmittance | permeability with respect to the wavelength and film thickness in a functional semiconductor were measured.
Table 4 shows data of Comparative Examples D-1 to D-3.

[Comparative Example E-1]
As the translucent substrate, an FTO / conductive glass substrate having a sheet resistance of 9 Ω / □ (Ω / cm ² ) is used instead of the ITO / PEN substrate, and the aqueous paste for forming a photoelectric conversion layer [1 In the same manner as in Example 1 except that a baking treatment was performed at 520 ° C. for 1 hour after the coating and drying treatment, and platinum was sputtered onto conductive glass as a counter electrode, a dye-sensitized solar for comparison was used. The battery [E-1] was obtained, and the values of the short circuit current, the open circuit voltage, the form factor ff, and the photoelectric conversion efficiency were obtained in the same manner as in Example 1 for the comparative dye-sensitized solar cell [E-1]. Under the present circumstances, when the surface observation was performed using SEM with respect to the obtained functional semiconductor layer, the trace extended in a specific direction like the roll press trace was not recognized. Moreover, the transmittance | permeability with respect to the wavelength and film thickness in a functional semiconductor were measured.
The data of Comparative Example E-1 is shown in Table 5.

In the dye-sensitized solar cell of the present invention according to Example 1 to Example 6, when a functional semiconductor layer is formed, a roll press process is performed so that the surface roughness Ra is 50 nm or less. It was confirmed that conversion efficiency was obtained.
Further, by comparing the results of Examples 1 and 5, it is confirmed that when the working electrode region is increased, the photoelectric conversion efficiency tends to be somewhat lowered, but almost the same photoelectric conversion efficiency can be obtained. It was done.

On the other hand, from the results of Comparative Examples D-1, D-2, and D-3 relating to the comparative dye-sensitized solar cells that were not subjected to the press treatment, high photoelectric conversion efficiency may not be obtained unless the press treatment is performed. confirmed. As a result, it is considered that the result of not performing the press treatment is that the bonding property between the titania particles and between the titania particles and the translucent substrate is low.
Further, from the results of Example 2, the solar cell using only one type of semiconductor particles having a small particle size has higher photoelectric conversion efficiency than that of the present invention using two types of semiconductor particles having different particle sizes. Although it was confirmed that it was not obtained, a dye-sensitized solar cell having high transmittance can be produced.

The roll press trace was observed by using SEM in Examples 1 to 6 where the roll press was performed. It was confirmed that the roll press trace was generated so as to extend in parallel with the rotation direction of the roll press. Further, in the measurement of the surface roughness Ra of the functional semiconductor layer using AFM, the surface roughness Ra is determined in a first direction parallel to the roll press treatment direction and a second direction orthogonal to the first direction. As a result of comparison, the surface roughness Ra in the second direction was larger than the surface roughness Ra in the first direction, showing a value of 1.2 times or more. This is considered to have occurred because the unevenness of the roll press trace resulting from the roll press treatment extends in the first direction.
In Comparative Examples A-1 to A-6 in which samples were produced using a flat press, no trace extending in a specific direction was observed like a roll press trace.

[Example F-1]
A dye-sensitized solar cell [F-1] was obtained in the same manner as in Example 1 except that the pressure of the roll press treatment was 80 MPa, and this dye-sensitized solar cell [F-1] and photoelectrode structure were obtained. The same measurement as in Example 1 was performed.

[Example F-2]
A dye-sensitized solar cell [F-2] was obtained in the same manner as in Example 1 except that the pressure was set to 160 MPa, and the dye-sensitized solar cell [F-2] and the photoelectrode structure were obtained. Measurements similar to those in Example 1 were performed.

[Example F-3]
A dye-sensitized solar cell [F-3] was obtained in the same manner as in Example 1 except that the pressure of the roll press treatment was 60 MPa, and this dye-sensitized solar cell [F-3] and photoelectrode structure were obtained. The same measurement as in Example 1 was performed.

[Example F-4]
A dye-sensitized solar cell [F-4] was obtained in the same manner as in Example 1 except that the pressure of the roll press treatment was 40 MPa, and this dye-sensitized solar cell [F-4] and photoelectrode structure were obtained. The same measurement as in Example 1 was performed.

[Comparative Example F-5]
A dye-sensitized solar cell [F-5] was obtained in the same manner as in Example 1 except that the conditions for the roll press treatment were 20 MPa, and this dye-sensitized solar cell [F-5] and photoelectrode structure were obtained. The same measurement as in Example 1 was performed.

[Comparative Example F-6]
A dye-sensitized solar cell [F-6] was obtained in the same manner as in Example 1 except that the pressure of the roll press treatment was 10 MPa, and this dye-sensitized solar cell [F-6] and photoelectrode structure were obtained. The same measurement as in Example 1 was performed.
For F-3 to F-6, the thickness of the functional semiconductor layer after pressing was 6 μm. Moreover, the transmittance is not measured. Furthermore, as for F-5 and F-6, since there was no roll press trace as will be described later, the surface roughness Ra was measured by the same method as in Comparative Example C-1.

[Example G-1]
A dye-sensitized solar cell [G-1] was obtained in the same manner except that the functional semiconductor film thickness was made lower than that in Example 1, and Example 1 was obtained for this dye-sensitized solar cell [G-1]. In the same manner, the values of short-circuit current, open-circuit voltage, form factor ff, and photoelectric conversion efficiency were obtained.
At this time, the obtained functional semiconductor layer was subjected to surface observation using SEM, and a roll press trace extending in parallel with the roll press treatment direction was confirmed.
Moreover, the transmittance | permeability with respect to the wavelength in a functional semiconductor and the film thickness before and behind a press process were measured.

[Example G-2]
A dye-sensitized solar cell [G-2] was obtained in the same manner except that the functional semiconductor film thickness was increased from that in Example 1, and Example 1 was obtained for this dye-sensitized solar cell [G-2]. In the same manner, the values of short-circuit current, open-circuit voltage, form factor ff, and photoelectric conversion efficiency were obtained.
At this time, the obtained functional semiconductor layer was subjected to surface observation using SEM, and a roll press trace extending in parallel with the roll press treatment direction was confirmed.
Moreover, the transmittance | permeability with respect to the wavelength in a functional semiconductor and the film thickness before and behind a press process were measured.

[Example H-1]
A photoelectric conversion layer-forming aqueous paste [1] obtained in the same manner as in Example 1 was applied to form a functional semiconductor layer, which was subjected to UV-ozone treatment, and then a sensitizing dye. To obtain dye-sensitized solar cells [H-1], and these dye-sensitized solar cells [H-1] were subjected to short-circuit current, open-circuit voltage, form factor ff, photoelectric in the same manner as in Example 1. The value of conversion efficiency was obtained.

(UV-ozone treatment)
The object to be treated was placed in a UV-ozone cleaning device “OC-2506” (manufactured by Iwasaki Electric Co., Ltd.) and irradiated with ultraviolet rays for 5 minutes.

  The data for Examples F-1, F-2, G-1, G-2, and H-1 are shown in Table 6.

  Table 7 shows data of Examples F-3 and F-4 and Comparative Examples F-5 and F-6.

As shown in Examples F-3 and F-4 in Table 7, the surface roughness Ra of the functional semiconductor layer is kept at 50 nm or less even when the pressure of the roll press treatment is reduced to 40 MPa, and the battery performance is improved. There was no change. On the other hand, in Comparative Examples F-5 and F-6 in which the pressure was further lowered, no roll press trace was observed on the surface of the functional semiconductor layer, and the surface roughness Ra exceeded 50 nm. Furthermore, the battery performance of Comparative Examples F-5 and F-6 was significantly reduced as compared with Examples F-3 and F-4. This is considered to be due to the fact that the adhesion of the semiconductor particles in the functional semiconductor layer is reduced due to the pressure drop, and as a result, it is difficult for electrons to move in the photoelectric conversion layer. In Comparative Examples F-5 and F-6, the decrease in the numerical value of the form factor (fill factor) can be said to be one of the support of this assumption.
This also indicates that the roll press trace is not a phenomenon that naturally occurs due to the roll press process, but is an index indicating that the adhesion degree of the semiconductor particles in the functional semiconductor layer is good.

In addition, as shown in Table 6, it is shown that when the functional semiconductor layer is subjected to UV-ozone treatment, a high photoelectric conversion efficiency can be obtained when not performed, for example, as compared with Example 1. It was.
This is because the hydrophilic groups of the semiconductor particles contained in the functional semiconductor layer are increased by the UV-ozone treatment of the functional semiconductor layer, and the semiconductor particles are likely to adsorb the dye. It is assumed that the solar cell can obtain high photoelectric conversion efficiency.

10, 10A Photoelectric conversion element 12 Electrolyte part 16 Counter electrode 17 Connection 20, 20A Photoelectrode 20K, 20L Photoelectrode structure 21 Translucent substrate 21a Translucent support 21b Transparent conductive layer 23, 26 Photoelectric conversion layer 23A Coating film 23B Layer 23C Coating film 23α, 23β Functional semiconductor layer 25 Light scattering layer

Claims (9)

The functional semiconductor layer of a photoelectrode structure in which a functional semiconductor layer is provided on the transparent conductive layer of a transparent substrate formed by forming a transparent conductive layer on an elastic plastic transparent support. A dye-sensitized solar cell photoelectrode having a sensitizing dye supported thereon,
The functional semiconductor layer has a layer subjected to a roll press treatment in contact with the transparent conductive layer, and the surface of the layer subjected to the roll press treatment has a roll press trace extending in parallel with the roll press treatment direction. And a photoelectrode for a dye-sensitized solar cell, having a surface roughness Ra of 50 nanometers or less.   2. The dye-sensitized solar cell photoelectrode according to claim 1, wherein a thickness of the functional semiconductor layer subjected to roll press treatment is 1 to 40 μm.   The said functional semiconductor layer contains a particle | grain with an average particle diameter of 2-40 nm, The photoelectrode for dye-sensitized solar cells of Claim 1 or 2 characterized by the above-mentioned.   The dye enhancement according to claim 1 or 2, wherein the functional semiconductor layer contains two or more kinds of particles having different average particle diameters, and the average particle diameter of at least one kind of particles is 2 to 40 nm. Photoelectrode for solar cell.   5. The dye-sensitized solar cell according to claim 4, wherein the two or more kinds of particles having different average particle sizes have a content ratio of particles having an average particle size of 2 to 40 nm of 50 to 95% by mass. Photoelectrode.   The light transmission at a wavelength of 500 nm is 20 to 85% and the light transmittance at a wavelength of 700 nm of the laminate comprising the light-transmitting substrate and the roll-pressed layer of the functional semiconductor layer in the photoelectrode structure. It is 30 to 85%, The photoelectrode for dye-sensitized solar cells as described in any one of Claims 1-5 characterized by the above-mentioned.   A dye-sensitized solar cell photoelectrode according to any one of claims 1 to 6, wherein the dye-sensitized solar cell photoelectrode is provided so as to face the counter electrode via an electrolyte portion. And a dye-sensitized solar cell. Photoelectrode for dye-sensitized solar cell formed by laminating photoelectric conversion layer on transparent conductive layer of transparent substrate having transparent conductive layer formed on elastic plastic transparent support. A manufacturing method of
The photoelectric conversion layer contains particles and a sensitizing dye,
Applying the paste containing the particles onto the transparent conductive layer to form a coating film, then subjecting the coating film to a roll press treatment at a pressure of 40 MPa or more and 500 MPa or less to form a roll press trace, and the roll press And a step of supporting a sensitizing dye on a layer obtained by the treatment. A method for producing a photoelectrode for a dye-sensitized solar cell, comprising:   The method for producing a photoelectrode for a dye-sensitized solar cell according to claim 8, wherein the translucent substrate has a surface of the transparent conductive layer subjected to UV-ozone treatment.