JP2005285472A - Photoelectric conversion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an excellent photoelectric conversion device capable of enhancing a conversion efficiency, as well as realizing lower cost and further moderating greatly the problems with resistance to weather and durability. <P>SOLUTION: A photoelectric conversion device includes a support substrate 1 on which a metal layer serving as an only one side electrode is formed on its surface, a photosensitive layer 2 formed on the metal layer of the support substrate 1 and containing a semiconductor onto which a sensitizing pigment 3 is adsorbed, a transparent electroconductive layer 5 arranged opposite to the metal layer of the support substrate 1, and a charge transfer layer 4 charged between the metal layer of the support substrate 1 and transparent conductive layer 5. The surface of the metal layer on which the photosensitive layer 2 is formed is a rough surface. Since a moderate irregularity is formed on the metal layer of the support substrate 1 or on the metal layer, the metal and the photosensitive layer 2 are adhered firmly. Therefore, resistance to weather and durability of the photoelectric conversion device can be improved. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a photoelectric conversion device that can be expected to have high photoelectric conversion efficiency, is excellent in weather resistance and durability, and can be reduced in cost.

Since dye-sensitized solar cells do not require high-temperature treatment or vacuum equipment, it is considered advantageous for reducing the cost of solar cells, and research and development have been promoted rapidly in recent years.
In this method for producing a dye-sensitized solar cell, for example, a photosensitive layer containing titanium oxide fine particles having a particle size of several tens of nanometers is applied on a conductive glass substrate and sintered to obtain a porous titanium oxide layer. A single molecule of organic dye is adsorbed on the particle surface of the titanium oxide layer. The pole thus formed is referred to as a “light working electrode”. On top of this, a transparent conductive glass counter electrode sputtered with platinum is placed so as not to contact the titanium oxide layer. An electrolyte solution containing an iodine / iodide redox pair is filled between both glass substrates, and this electrolyte solution is sealed to fabricate a solar cell.

By making the titanium oxide layer porous, the surface area of the light working electrode can be increased by 1000 times or more, and light absorption by the adsorbing dye can be efficiently performed. Photoelectric conversion efficiency of about 10% at the research level and around 7% at the reproduction level is known. For this reason, further improvement in photoelectric conversion efficiency is required for market introduction.
Japanese Patent Laid-Open No. 2001-273937

Incidentally, as one of the problems of the dye-sensitized solar cell, there is a demand for increasing the interface strength between the substrate and the photosensitive layer containing semiconductor fine particles.
If the adhesion between the substrate and the photosensitive layer containing semiconductor fine particles is poor, the weather resistance and durability are lowered, and the reliability of the solar cell is lowered. In addition, the contact area between the substrate and the photosensitive layer containing the semiconductor is reduced. As a result, the internal resistance of the solar cell is increased, and the conversion efficiency of the solar cell is lowered.

  Also, when considering increasing the area of the solar cell, it is necessary to reduce the internal resistance of the solar cell. However, if the adhesion between the substrate and the photosensitive layer containing semiconductor fine particles is poor, the internal resistance of the solar cell is reduced. Conventionally, it has been necessary to reduce resistance loss by providing silver and other current collectors at regular intervals. However, in this case, there is a problem of corrosion of the collector wire due to the electrolyte, and it is necessary to change the components of the electrolyte to those that do not corrode the collector electrode together with the installation of a protective layer for protecting the collector wire . In addition, such a collector electrode has a problem that the effective photoelectric conversion area of the battery is lowered.

  An object of the present invention is to provide an excellent photoelectric conversion device capable of increasing the conversion efficiency, reducing the cost, and greatly reducing the problems of weather resistance and durability.

The photoelectric conversion device of the present invention includes a support substrate having a metal layer serving as one electrode on the surface, a photosensitive layer formed on the metal layer and including a semiconductor to which a sensitizing dye is adsorbed, and a metal layer. The surface of the metal layer on which the photosensitive layer is formed includes a transparent conductive layer disposed opposite to the photosensitive layer and a charge transfer layer filled between the photosensitive layer and the transparent conductive layer. It is characterized by that.
The support substrate may itself be made of a metal plate.

According to the configurations of these inventions, the metal layer and the metal plate of the support substrate have moderate irregularities, so that the metal and the photosensitive layer containing the semiconductor are firmly fixed. Therefore, the weather resistance and durability of the photoelectric conversion device can be improved.
In addition, since moderate irregularities are formed on the metal, the contact area with the photosensitive layer containing the semiconductor increases, the internal resistance of the photoelectric conversion device decreases, and the photocurrent increases.

Furthermore, since the specific resistance of the metal itself is small, the sheet resistance of the metal layer of the support substrate or the metal plate can be reduced. For this reason, even when the area is increased, the internal resistance of the photoelectric conversion device does not increase and the photocurrent does not decrease.
Furthermore, since moderate irregularities are formed on the metal, the light transmitted from the upper part can be reflected and diffused, and the energy of the incident light can be used effectively. For this reason, it leads to the increase in photoelectric conversion efficiency.

The semiconductor in the photosensitive layer is composed of a large number of semiconductor particles, and the size of the concave portion of the rough surface is preferably such that a predetermined proportion or more of these semiconductor particles can be accepted.
More specifically, when the average opening angle in the concave portion of the rough surface is θ, the arithmetic average roughness of the rough surface is Ra, and the particle size of individual particles of the semiconductor in the photosensitive layer is L, the following The abundance of semiconductor particles satisfying the formula is preferably 10% or more.

L ≦ 2Ra · tan (θ / 2)
Here, the arithmetic average roughness Ra is obtained by extracting only the reference length D from the roughness curve in the direction of the average line, taking the X axis in the direction of the average line of the extracted portion, and the Y axis in the direction perpendicular to the plane. When the roughness curve is represented by y = f (x), it means a value obtained by the following formula (JIS B 0601 (1994)).

Ra = (1 / D) ∫ | f (x) | dx (Integration is from x = 0 to x = D)
When the abundance ratio of the semiconductor particles having the particle size L satisfying this formula is less than 10%, the adhesion strength between the semiconductor and the metal is lowered, and the photosensitive layer is easily peeled off.
The thickness of the metal layer on the surface of the support substrate is preferably 0.01 μm or more and 2 mm or less. When the thickness of the metal layer is less than 0.01 μm, sufficient conductivity cannot be obtained, so that the internal resistance increases and the characteristics deteriorate. In addition, when the thickness of the metal layer exceeds 2 mm, the cost is high and the photoelectric conversion device becomes heavy.

   Moreover, it is preferable that the thickness of the said metal plate is 0.01 mm or more and 2 mm or less. When the thickness of the metal plate is less than 0.01 mm, the strength of the metal plate cannot be maintained. When the thickness of the metal plate exceeds 2 mm, the material cost is high and the photoelectric conversion device becomes heavy.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings, taking a dye-sensitized solar cell as an example of the photoelectric conversion device of the present invention.
FIG.1 and FIG.2 is sectional drawing which shows the structure of a dye-sensitized solar cell.
This dye-sensitized solar cell has a support substrate 1 serving as one electrode and a photosensitive layer 2 formed on the support substrate 1 and containing a semiconductor to which a sensitizing dye 3 is adsorbed. Further, a translucent substrate 6 having a transparent conductive layer 5 formed on the lower surface is disposed opposite to the support substrate 1, and the charge transfer layer 4 is filled between the support substrate 1 and the transparent conductive layer 5. Has been.

The support substrate 1 may be a single metal substrate as shown in FIG. 1 or a conductive film 1a formed on an insulating substrate 1b as shown in FIG.
Examples of the single metal substrate include thin metal substrates such as titanium, stainless steel, aluminum, silver, and copper. Further, a conductive resin sheet impregnated with fine particles or fine wires of carbon or metal may be employed.

When the conductive film 1a is formed on the insulating substrate 1b, the insulating substrate 1b includes a resin sheet such as PET (polyethylene terephthalate), PEN (polyethylene naphthalate), polyimide, polycarbonate, soda glass, borosilicate glass, An inorganic sheet such as ceramic or an organic-inorganic hybrid sheet is preferable. As the conductive film 1a formed thereon, a metal thin film such as titanium, stainless steel, aluminum, silver or copper, a transparent conductive film such as ITO, SnO ₂ : F, ZnO: Al, Ti / Ag / Ti, Ti / ITO A laminated conductive film such as / Ti is preferable.

  The method for laminating the conductive film 1a is arbitrary. For example, a vacuum deposition method, an ion plating method, a sputtering method, an electrolytic deposition method, or the like can be employed. It may be formed by a plating method or a printing method. It can also be formed by transferring a metal foil onto an insulating resin substrate. The thickness of the conductive film 1a to be formed is in the range of 0.01 μm to 2 mm, preferably in the range of 3 μm to 2 mm, and more preferably in the range of 50 μm to 0.5 mm.

Note that if the support substrate 1 has light reflectivity, the transmitted light can be reflected and reused. Therefore, it is preferable to use a conductive material having high light reflectivity.
According to the present invention, the conductive film 1a formed on the metal substrate or insulating substrate 1b needs to be a surface having fine irregularities, that is, a rough surface.
Examples of the shape of the concave or convex portion of the unevenness include a conical shape and a polygonal pyramid shape. The size distribution of the unevenness may be uniform or non-uniform, but if it is uniform, a process for aligning the size of the unevenness is required, and therefore, it is advantageous in terms of cost. It is preferable to have a smooth curved surface on the side surface and the top portion of the unevenness because the dependency on the ray angle of light is reduced.

As shown in FIG. 3, the size of the concave portion of the rough surface is such a size that a certain percentage (for example, 10%) or more of many semiconductor particles formed on the rough surface can be accepted. It is desirable that
As a method for evaluating whether a certain ratio or more can be accepted in the concave portion of the rough surface, the arithmetic average roughness of the rough surface is Ra, and the particle size (diameter) of each semiconductor particle in the photosensitive layer 2 is When it is set to L, it is preferable that the abundance ratio of the semiconductor particles satisfying the following formula (1) is a certain ratio or more, for example, 10% or more.

L ≦ 2Ra · tan (θ / 2) (1)
FIG. 4 is an enlarged cross-sectional view of a rough surface. When the opening angle of the recess is θ and the depth of the recess is Ra, the opening diameter of the recess is represented by 2Ra · tan (θ / 2). Therefore, whether or not individual particles of the semiconductor enter this recess can be determined based on the inequality (1).
The method of roughening the conductive film 1a on the metal substrate or the insulating substrate 1b includes a sandblasting method in which a pressurized gas containing fine particles such as alumina is blown onto the surface of the substrate to physically scrape, or a plasma gas such as CF4. There are a chemical dry etching method in which the substrate is exposed to the substrate and an etching method using a chemical solution.

For the photosensitive layer 2 including a semiconductor formed on the support substrate 1, a porous one-conductive transporter is used. By making this one-conductivity-type transporter a porous body, the pn junction area is increased, the surface area for supporting the dye is increased, and the photoelectric conversion efficiency can be increased.
As the material for the one conductivity type transporter, a metal oxide semiconductor is usually used. This metal oxide semiconductor is preferably formed by aggregating a plurality of granular bodies or linear bodies (needle-like bodies, tube-like bodies, columnar bodies, etc.).

Titanium oxide (TiO ₂ ) is optimal as the material and composition of the metal oxide semiconductor. Other materials and compositions include titanium (Ti), zinc (Zn), tin (Sn), niobium (Nb), indium (In), yttrium (Y), lanthanum (La), zirconium (Zr), tantalum (Ta ), Hafnium (Hf), strontium (Sr), barium (Ba), calcium (Ca), cadmium (Cd), antimony (Sb), iron (Fe), tungsten (W) and vanadium (V) Of these, a metal oxide semiconductor containing at least one of them as a main component is preferable.

Specific examples include tin oxide, indium oxide, zinc oxide, cadmium oxide, antimony oxide, iron oxide, tungsten oxide, titanium oxide, and strontium titanate.
In addition, these metal oxide semiconductors contain one or more of non-metallic elements such as nitrogen (N), carbon (C), fluorine (F), sulfur (S), chlorine (Cl), and phosphorus (P). You may let them.

Any of these metal oxide semiconductors has an electronic energy band gap in the range of 2 eV to 5 eV, which is larger than the energy of visible light. In particular, an n-type semiconductor in which the electronic energy level of the conduction band of the metal oxide semiconductor is lower than the electronic energy level of the conduction band of the dye is preferable.
The metal oxide semiconductor is preferably a porous body having a porosity of 20% to 80%, more preferably 40% to 60%. The reason for this is that a porous material with this degree of porosity can increase the surface area of the light working electrode to more than 1000 times that of a zero-porosity material, thus improving the efficiency of light absorption, power generation, and electron conduction. This is because it can be done well.

  The shape of the porous body is preferably a shape having a large surface area and a small electrical resistance. Usually, it should be composed of fine particles or fine lines. The average particle diameter or average line diameter is preferably 5 nm to 500 nm, and more preferably 10 nm to 200 nm. Here, if the lower limit value 5 nm in the average wire diameter of 5 nm to 500 nm is less than this, it becomes difficult to make the material finer, and if the upper limit value 500 nm is exceeded, the pn junction area is reduced and the photocurrent is significantly reduced. It is.

The film thickness of the metal oxide semiconductor is preferably 0.1 μm to 50 μm, and more preferably 1 μm to 20 μm. Here, the lower limit value of 0.1 μm to 0.1 μm between 0.1 μm and 50 μm cannot be used because the photoelectric conversion effect is significantly reduced when the film thickness becomes smaller than this, and the upper limit value of 50 μm allows light to be transmitted when the film thickness becomes thicker than this. This is because the conversion efficiency does not increase.
In addition, when the semiconductor becomes ultrafine particles, the band gap is no longer a value inherent to the material and depends on the size. Even with a material with a very small intrinsic band gap (1 eV or less), the band gap can be reduced by nano-sizing. Since it can be increased, the absorption wavelength can be selected, and the sensitivity can be easily increased. Examples of the ultrafine particle semiconductor include CdS, CdSe, PbS, PbSe, CdTe, Bi ₂ S ₃ , InP, and Si.

As the sensitizing dye 3 to be adsorbed on the photosensitive layer 2 containing the semiconductor, it is effective to use a dye having a characteristic that the photocurrent efficiency (IPC) with respect to incident light extends to the long wavelength side. It is.
A bis-type squarylium cyanine dye can be given as a dye having such sensitivity extending to the longer wavelength side. This bis-type squarylium cyanine dye has an IPCE peak wavelength near 800 nm. In addition, azurenium salt compounds having a high IPCE at a wavelength of 700 nm or more, squalinic acid derivatives, triallylpyrazoline, hydrazone derivatives, biphenyldiamine derivatives, tri-p-tolylamine (TPTA), trisazo pigments, τ-type metal-free phthalocyanine, titanyl It is also effective to use dyes such as phthalocyanine, squarylium cyanine, black dye, coumarin, β-diketonate, Re complex, Os complex, Ni complex, Pd complex, and Pt complex.

As other examples of the dye, in addition to the metal complex dye, the organic dye, and the organic pigment, an inorganic dye, an inorganic pigment, an inorganic semiconductor, and the like may be used. In addition, the shape of the dye only needs to be at least one of molecules, ultrathin films, fine particles, ultrafine particles, and quantum dots.
As the translucent substrate 6, white plate glass having a small iron component has the highest transmittance and the best mechanical strength. In addition, a light-transmitting inorganic substrate such as blue plate glass, borosilicate glass, soda glass, ceramic, and sapphire, or a light-transmitting organic resin substrate such as polycarbonate may be used.

Further, the translucent substrate 6 may be flat on both sides, but it is better that the surface having an unevenness of the order of the wavelength of incident light has a light confinement effect.
The thickness of the translucent substrate 6 is preferably 0.05 mm to 6 mm depending on the material, the substrate size, and the use, and is preferably 3 mm to 4 mm from the viewpoint of strength and weight if it is used for roofing of glass and metric size.

The transparent conductive layer 5 is preferably a tin-doped indium oxide film (ITO film) produced by a low temperature growth sputtering method or a low temperature spray pyrolysis method. In addition, an impurity-doped zinc oxide film (ZnO film) produced by a solution growth method, a fluorine-doped tin dioxide film (SnO ₂ : F film) formed by a thermal CVD method, an impurity-doped indium oxide film (In ₂ O) ₃ membranes) can be used. As other film forming methods, there are a vacuum deposition method, an ion plating method, a dip coating method, a sol-gel method, and the like. If surface irregularities in the order of the wavelength of incident light are formed by the growth of these films, there is still a light confinement effect.

As the charge transfer layer 4, a hole transporter such as a gel electrolyte (p-type semiconductor, liquid electrolyte, solid electrolyte, electrolytic salt, etc.) is preferably used.
The charge transfer layer 4 is formed so as to fill the porous body of the photosensitive layer 2 containing the semiconductor. In this sense, it is also called “reverse porous body”. The electrolytic solution shows the best carrier mobility, but because of problems such as liquid leakage, gelled or solidified ones are preferred.

Examples of the material for the charge transfer layer 4 include transparent conductive oxides, electrolyte solutions, electrolytes such as gel electrolytes and solid electrolytes, organic hole transport agents, and ultrathin metal films.
As the transparent conductive oxide, a compound semiconductor containing monovalent copper, GaP, NiO, CoO, FeO, Bi ₂ O ₃ , MoO ₂ , Cr ₂ O _3, etc. are preferable. Among them, a compound containing monovalent copper A semiconductor is good. As the compound semiconductor containing monovalent copper, CuI, CuInSe ₂ , Cu ₂ O, CuSCN, CuS, CuInS ₂ , CuAlSe ₂ and the like are preferable, and among these, CuI and CuSCN are preferable, and CuI is most preferable because it is easy to manufacture.

As the electrolyte solution, a quaternary ammonium salt or a Li salt is used. As the composition of the electrolyte solution, for example, a solution prepared by mixing tetrapropylammonium iodide, lithium iodide, iodine, or the like with ethylene carbonate, acetonitrile, methoxypropionitrile, or the like can be used.
The gel electrolyte is roughly classified into a chemical gel and a physical gel. A chemical gel is a gel formed by chemical bonding by a cross-linking reaction or the like, and a physical gel is gelled near room temperature due to physical interaction. As the gel electrolyte, acetonitrile, ethylene carbonate, propylene carbonate, or a mixture thereof was polymerized by mixing a host polymer such as polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride, polyvinyl alcohol, polyacrylic acid, polyacrylamide or the like. A gel electrolyte is preferred. When using a gel electrolyte or solid electrolyte, a low-viscosity precursor is included in the oxide semiconductor layer, and a two-dimensional or three-dimensional crosslinking reaction is caused by means such as heating, ultraviolet irradiation, or electron beam irradiation. Can be gelled or solidified.

  The solid electrolyte is preferably a solid electrolyte having a polymer chain such as polyethylene oxide, polyethylene oxide, or polyethylene having a salt such as sulfonimidazolium salt, tetracyanoquinodimethane salt, or dicyanoquinodiimine salt. As the molten salt of iodide, iodides such as imidazolium salt, quaternary ammonium salt, isoxazolidinium salt, isothiazolidinium salt, pyrazolidium salt, pyrrolidinium salt, pyridinium salt can be used.

  Examples of the molten salt of iodide include 1,1-dimethylimidazolium iodide, 1, methyl-3-ethylimidazolium iodide, 1-methyl-3-pentylimidazolium iodide, 1-methyl- 3-isopentylimidazolium iodide, 1-methyl-3-hexylimidazolium iodide, 1-methyl-3-ethylimidazolium iodide, 1,2-dimethyl-3-propylimidazole iodide, 1-ethyl- Examples thereof include 3-isopropylimidazolium iodide and pyrrolidinium iodide.

Examples of the organic hole transporting agent include triphenyldiamine (TPD1, TPD2, TPD3) and OMeTAD.
Next, the manufacturing method of this dye-sensitized solar cell is demonstrated.
First, a dispersion of semiconductor fine particles is prepared. In addition to the sol / gel method described above, this method can be used by grinding in a mortar, dispersing by pulverizing using a mill, or precipitating as fine particles in a solvent when synthesizing a semiconductor. Methods and the like.

  Examples of the dispersion medium include water or various organic solvents (for example, methanol, ethanol, isopropyl alcohol, dichloromethane, acetone, acetonitrile, ethyl acetate, and the like). At the time of dispersion, a polymer such as polyethylene glycol, a surfactant, an acid, a chelating agent, or the like may be used as a dispersion aid as necessary. By changing the molecular weight of polyethylene glycol, a film that does not easily peel off can be formed, and the viscosity of the dispersion can be adjusted. Therefore, it is preferable to add polyethylene glycol.

Next, the semiconductor fine particles are disposed on the support substrate 1. For this, the dispersion or colloidal solution of the semiconductor fine particles may be applied on the support substrate 1, and there is a method of printing the semiconductor fine particles on the support substrate 1 in addition to this method.
Examples of the application method include a roller method and a dip method as application systems, and an air knife method and a blade method as metering systems. In addition, as the application and metering can be applied to the same part, the wire bar method disclosed in Japanese Patent Publication No. 58-4589, the slide hopper method disclosed in US Pat. Nos. 2681294, 2761419, 2761791, etc. And the extrusion method and the curtain method. A spin method and a spray method are also preferable.

As the wet printing method, intaglio, rubber plate, screen printing and the like are preferred, including the three major printing methods of letterpress, offset and gravure. From these, a preferred film forming method is selected according to the liquid viscosity and the wet thickness.
The viscosity of the dispersion of semiconductor fine particles greatly depends on the type and dispersibility of the semiconductor fine particles, the type of solvent used, and additives such as surfactants and binders. For a high viscosity liquid (for example, 0.01 to 500 Poise), an extrusion method, a casting method, a screen printing method, or the like is preferable. For low-viscosity liquids (for example, 0.1 Poise or less), the slide hopper method, wire bar method, or spin method is preferable, and a uniform film can be formed thereby. If there is a certain amount of coating, coating by the extrusion method is possible even in the case of a low viscosity liquid. As described above, a wet film forming method may be appropriately selected according to the viscosity of the coating liquid, the coating amount, the support substrate 1, the coating speed, and the like.

  The semiconductor fine particle layer is not limited to a single layer, but a multi-layer coating of a dispersion of semiconductor fine particles having different particle diameters, or a multi-layer coating of a coating layer containing different types of semiconductor fine particles (or different binders and additives) You can also Multi-layer coating is also effective when the film thickness is insufficient with a single coating. For multilayer coating, an extrusion method or a slide hopper method is suitable. In the case of applying multiple layers, the multiple layers may be applied at the same time, or may be successively applied several times to several dozen times. Further, screen printing can be preferably used as long as it is sequentially overcoated.

In general, as the thickness of the semiconductor fine particle layer (same as the thickness of the photosensitive layer 2) increases, the amount of the supported dye increases per unit projected area, so that the light capture rate increases, but the diffusion distance of the generated electrons increases, resulting in an increase in charge. Loss due to recombination also increases. Therefore, the preferable thickness of the semiconductor fine particle layer is 0.1 to 100 μm. When used in a solar cell, the thickness of the semiconductor fine particle layer is preferably 0.5 to 30 μm, more preferably 1 to 25 μm. The coating amount of the semiconductor fine particles per 11 m ² of the support substrate is preferably 0.5 to 400 g, more preferably 1 to 100 g.

After coating, the semiconductor fine particle layer is baked in the atmosphere at 300 ° C. to 600 ° C., preferably 400 ° C. to 500 ° C., for 10 minutes to 60 minutes, preferably 20 minutes to 40 minutes. Thus, a porous metal oxide semiconductor is produced. This technique is simple and effective when it can be formed in advance on a heat-resistant conductive sheet.
Next, the dye is adsorbed to the porous photosensitive layer 2 containing a semiconductor. Examples of the adsorption method include a method in which a substrate on which a photosensitive layer 2 containing a semiconductor is formed is immersed in a solution in which a dye is dissolved. When the substrate on which the photosensitive layer 2 containing a porous semiconductor is formed is immersed in a solution in which a dye is dissolved, the temperature of the solution and the atmosphere is not particularly limited, and examples include room temperature under atmospheric pressure. . The immersion time can be appropriately adjusted depending on the pigment, the type of solvent, the concentration of the solution, and the like. Thus, the dye can be adsorbed on the photosensitive layer 2 containing the porous semiconductor.

Examples of the solvent used for dissolving the dye include a mixture of one or more alcohols such as ethanol, ketones such as acetone, ethers such as diethyl ether, nitrogen compounds such as acetonitrile, and the like.
Further, the dye concentration in the solution is preferably about 5 × 10 ⁻⁵ to 2 × 10 ⁻³ mol / l.
Next, the translucent substrate 6 on which the transparent conductive layer 5 is formed is disposed on the support substrate 1 so that the transparent conductive layer 5 is on the bottom. At this time, the transparent conductive layer 5 is prevented from contacting the photosensitive layer 2 containing a semiconductor. In this state, the charge transfer layer 4 is injected between the transparent conductive layer 5 and the photosensitive layer 2 containing a semiconductor, and the space between the support substrate 1 and the translucent substrate 6 is sealed. The transparent conductive layer 5 may be provided with a collector electrode to reduce the electrical resistance.

In this way, a dye-sensitized solar cell can be produced.
In the present invention, at least the surface of the support substrate 1 is made of a metal layer, and the surface of the metal layer on which the photosensitive layer 2 is formed is a rough surface, so that the metal and the photosensitive layer 2 containing a semiconductor are firmly fixed, The weather resistance and durability of the photoelectric conversion device can be improved.

As a support substrate, porous titanium dioxide as an electron transporter was formed on a titanium sheet (size: 1 cm × 2 cm) having a thickness of 0.3 mm. The titanium dioxide was produced by first adding acetylacetone to TiO ₂ anatase powder and then kneading with deionized water to prepare a titanium oxide paste stabilized with a surfactant. The prepared paste was applied at a constant speed onto the surface on which the translucent conductive film was formed by the doctor blade method, and baked at 450 ° C. for 30 minutes in the air.

N719 dye is used as the dye, acetonitrile and t-butanol (1: 1 by volume) are used as the solvent used to dissolve the dye, and the support substrate on which the metal oxide semiconductor layer is formed is dissolved in the dye. The dye was supported on the metal oxide semiconductor by dipping in the solution.
Next, platinum was coated on a PET film with an ITO film by a sputtering apparatus. The transparent conductive sheet and the dye-supported titanium dioxide-attached titanium sheet were faced to each other, and the following electrolytic solution was added between the transparent conductive sheet and lightly bonded to evaluate the characteristics.

Here, as the hole transporter, a gel electrolyte or a solid electrolyte is preferable, but in this example, iodine (I ₂ ), lithium iodide (LiI) and acetonitrile solutions as liquid electrolytes were prepared and used. In this way, a dye-sensitized solar cell was produced.
The dye-sensitized solar cell thus obtained was measured at 100 mW / cm ² under AM 1.5, and as a result, the photoelectric conversion efficiency was improved by 20% or more compared to the stacked solar cell not subject to the present invention.

  As described above, in this example, the dye-sensitized solar cell of the present invention can be easily and easily manufactured, and high photoelectric conversion efficiency can be realized.

It is sectional drawing which shows the structure of the dye-sensitized solar cell which consists of a single metal substrate of this invention. It is sectional drawing which shows the structure of the dye-sensitized solar cell which formed the electrically conductive film 1a on the insulated substrate 1b of this invention. It is sectional drawing which shows the unevenness | corrugation of the said rough surface. It is an expanded sectional view of unevenness.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Support substrate 1a Conductive film 1b Insulating substrate 2 Photosensitive layer 3 Sensitizing dye 4 Charge transfer layer 5 Transparent conductive layer 6 Translucent substrate

Claims (6)

A support substrate on which a metal layer serving as one electrode is formed;
A photosensitive layer comprising a semiconductor formed on the metal layer and adsorbed with a sensitizing dye;
A transparent conductive layer disposed opposite the metal layer;
A charge transfer layer filled between the photosensitive layer and the transparent conductive layer,
The surface of the said metal layer in which the said photosensitive layer is formed is a rough surface, The photoelectric conversion apparatus characterized by the above-mentioned. On the other hand, a support substrate made of a metal plate to be an electrode,
A photosensitive layer comprising a semiconductor formed on the support substrate and adsorbed with a sensitizing dye;
A transparent conductive layer disposed facing the support substrate;
A charge transfer layer filled between the photosensitive layer and the transparent conductive layer,
The surface of the said metal plate in which the said photosensitive layer was formed is a rough surface, The photoelectric conversion apparatus characterized by the above-mentioned.   The semiconductor in the photosensitive layer is composed of a large number of semiconductor particles, and the size of the concave portion of the rough surface is such that a predetermined proportion or more of these semiconductor particles can be accepted. 2. The photoelectric conversion device according to 2. Semiconductor particles satisfying the following formula, where θ is the average opening angle in the concave portion of the rough surface, Ra is the arithmetic average roughness of the rough surface, and L is the individual particle size of the semiconductor particles in the photosensitive layer The photoelectric conversion device according to claim 3, wherein the abundance ratio is 10% or more.
L ≦ 2Ra · tan (θ / 2)   The said metal layer or the said metal plate has as a main component 1 or more types of metals chosen from aluminum, copper, titanium, nickel, iron, zinc, and molybdenum. The photoelectric conversion apparatus in any one.   The semiconductor includes, as a main component, at least one oxide selected from tin oxide, indium oxide, zinc oxide, cadmium oxide, antimony oxide, iron oxide, tungsten oxide, titanium oxide, and strontium titanate. The photoelectric conversion device according to any one of claims 1 to 5.

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