JP4942349B2 - Dye-sensitized solar cell, manufacturing method thereof, and manufacturing apparatus - Google Patents

Description

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

  Solar cells that use sunlight as an energy source to replace fossil fuels have attracted attention and various studies have been conducted. The mainstream solar cells currently in practical use are single crystal, polycrystalline, and amorphous silicon, but these have high material costs and high energy costs in the manufacturing process, which is a major obstacle to the spread of solar cells. It has become.

  Therefore, a dye-sensitized solar cell has attracted attention as a solar cell that can be manufactured at low cost.

  A dye-sensitized solar cell includes a working electrode composed of a porous semiconductor layer that adsorbs a dye, a counter electrode, and a charge transport layer sandwiched between the working electrode and the counter electrode, and light incident on the working electrode is dyed. When the electrons inside are excited, the electrons quickly move to the porous semiconductor. The dye that has lost the electrons receives electrons from the ions in the charge transport layer, and the ions that have lost the electrons diffuse to the counter electrode and receive electrons from the counter electrode. By such circulation, light is converted into electric energy.

  Here, if the working electrode and the counter electrode are electrically connected (preferably via a conductive layer formed in contact with the porous semiconductor), a current flows continuously, and the device operates as a solar cell.

  Such a dye-sensitized solar cell can obtain the same level of photoelectric conversion efficiency (for example, 5 to 8%) as that of an amorphous silicon solar cell, but further high efficiency is required for practical use.

  As a method for improving the photoelectric conversion efficiency of a dye-sensitized solar cell, a method is proposed in which at least a part of a porous semiconductor layer is covered with an oxide semiconductor having an energy level higher than the energy level of its conduction band. . For example, Japanese Patent Application Laid-Open No. 2000-111393 (Patent Document 1) describes a dye-sensitized solar cell in which a coating layer made of titanium oxide or zinc oxide is formed on a porous semiconductor layer made of fine particles such as tin oxide. Non-Patent Document 1 describes a dye-sensitized solar cell in which a coating layer made of zinc oxide is formed on a porous semiconductor layer made of titanium oxide fine particles. However, conventionally, in order to form another multilayer on the porous semiconductor layer, it is necessary to separately provide a dedicated manufacturing process and manufacturing apparatus, which increases the manufacturing cost and manufacturing tact time of the solar cell. This is not preferable.

  Further, the conventional dye-sensitized solar cell has the following problems. That is, the porous semiconductor layer used for the working electrode of the dye-sensitized solar cell is generally mixed with semiconductor fine particles (titanium oxide is preferably used) together with a solvent as shown in, for example, Japanese Patent No. 2664194 (Patent Document 2). Thus, a semiconductor paste is formed and applied to a support and fired.

  It is known that firing of such semiconductor fine particles usually requires heating at 450 ° C. or higher (800 ° C. or lower, preferably 600 ° C. or lower). This is because a porous semiconductor layer fired at a temperature lower than this may cause defects such as low electron mobility and low mechanical strength.

  On the other hand, there is a demand for a dye-sensitized solar cell having flexibility for the purpose of weight reduction, price reduction, and application to a curved surface.

  As a method for producing a dye-sensitized solar cell having flexibility, a porous semiconductor layer is formed on a flexible support, or a porous semiconductor layer formed on a heat-resistant substrate is separated, and a separate support is provided. The method of arranging and using can be mentioned.

  As an example of the former, a method of forming a porous semiconductor layer on a flexible metal support or resin support has been proposed. For example, Japanese Patent Laid-Open No. 2001-273937 (Patent Document 3) forms an oxide semiconductor layer on a metal support to prevent corrosion caused by an electrolytic solution (which constitutes a charge transport layer, which will be described in detail later). A dye-sensitized solar cell having an electrode formed therein is described. Japanese Patent Application Laid-Open No. 2005-251506 (Patent Document 4) describes a dye-sensitized solar cell using a polyester film as a support.

  As an example of the latter, JP-A-2002-299665 (Patent Document 5) describes a method of forming a porous semiconductor layer on a sacrificial substrate that can be removed with an aqueous solvent, and then dissolving the sacrificial substrate. JP-A-2005-166648 (Patent Document 6) laminates an intervening layer (a layer for controlling adhesion between a heat-resistant substrate and a porous semiconductor layer) and a porous semiconductor layer on a heat-resistant substrate. A method of peeling is described.

  In solar cells other than dye-sensitized solar cells (such as amorphous silicon solar cells), for example, in Japanese Patent Application Laid-Open No. 2001-358351 (Patent Document 7), a dissolved layer and a semiconductor layer are formed on a heat-resistant substrate, A method for separating a heat-resistant substrate and a semiconductor layer by dissolving a dissolved layer is described.

  These conventionally proposed methods for manufacturing flexible solar cells have the following characteristics, respectively.

First, the method of forming a porous semiconductor layer on a metal support has the advantage that heating at 450 ° C. or higher can be performed during firing of the porous semiconductor layer because the support is excellent in heat resistance. However, a metal having a thickness (for example, about 0.1 mm to 1 mm) having a strength and flexibility necessary for a support does not have a light transmission property. Therefore, a dye-sensitized solar cell using a metal support is on the counter electrode side. Must be the light incident surface. In this case, since incident light passes through the counter electrode and the charge transport layer and reaches the working electrode, an important catalyst as the counter electrode (in many cases, platinum fine particles or a thin film is used) and ions in the charge transport layer (many In this case, light absorption due to I ⁻ / I ₃ ⁻ is used, and the dye-sensitized solar cell is difficult to effectively use external light.

  On the other hand, when a resin support is used, light support from the working electrode side is possible by using a support made of a light-transmitting resin (for example, transmitting 50% or more of visible light on average). However, the resin support is inferior in heat resistance to the metal support, and it becomes difficult to heat at 450 ° C. or higher when firing the porous semiconductor layer.

  Further, according to the method of forming a porous semiconductor layer on the sacrificial substrate and dissolving and removing the sacrificial substrate, heating at 450 ° C. or higher is possible when the porous semiconductor layer is fired by using the heat-resistant sacrificial substrate. . Further, by supporting the separated porous semiconductor with a resin support, a dye-sensitized solar cell capable of effectively using external light is obtained. However, a sacrificial substrate made of, for example, potassium bromide or magnesium chloride is difficult to reuse, so that the manufacturing cost of the solar cell increases. In addition, a sacrificial substrate manufactured by impregnating magnesium chloride, sodium carbonate, or the like on a porous substrate (such as porous alumina) requires an impregnation / firing process in the manufacture of the sacrificial substrate, which increases manufacturing tact time. .

  Also, a method of separating the heat-resistant substrate and the porous semiconductor layer using an intervening layer produces a dye-sensitized solar cell that can be heated at 450 ° C. or more when firing the porous semiconductor layer and can effectively use external light. it can. However, the intervening layer in this manufacturing method adheres the heat-resistant substrate and the porous semiconductor layer satisfactorily during the formation of the porous semiconductor layer (such as coating and baking of the semiconductor paste), so that the porous semiconductor layer is supported on the support. Adhesion strength that satisfies the conflicting requirements of separating the heat-resistant substrate and the porous semiconductor layer well during transfer is necessary, and this adjustment is difficult.

In addition, a solar cell capable of heating at 450 ° C. or higher when firing the semiconductor layer and effectively using external light can be manufactured by a method of separating the heat-resistant substrate and the semiconductor layer by dissolving the layer to be dissolved. Furthermore, the layer to be dissolved (metal such as aluminum, zinc oxide, tin oxide or the like) does not require adjustment of adhesion strength as in the case of the intervening layer. However, since the method described in Patent Document 7 is a method for manufacturing a semiconductor layer for a solar cell using amorphous silicon, polycrystalline silicon, polycrystalline compound semiconductor, etc., it is caused by undissolved or undissolved layer to be dissolved. If ions or the like remain on the semiconductor layer, the photoelectric conversion performance is deteriorated. For this reason, it is necessary to clean the separated semiconductor layer very precisely.

Kim et al / Solar Energy Materials & Solar Cells 79 (2003) 495-505. JP 2000-119133 A Japanese Patent No. 2664194 JP 2001-273937 A JP 2005-251506 A JP 2002-299665 A JP 2005-166648 A JP 2001-358351 A

  An object of the present invention is to solve the above-mentioned conventional problems in a dye-sensitized solar cell and a method for producing the same. Specifically, a porous semiconductor layer formed by heating at 450 ° C. or more is used as a working electrode, and a flexible resin support that can be reduced in weight, reduced in price, applied to a curved surface, and the like is used. An object is to provide an efficient dye-sensitized solar cell and a method for producing the same. Preferably, a metal or metal salt that is a raw material of a metal oxide having a conduction band energy higher than that of a semiconductor constituting the porous semiconductor layer is used as a dissolved layer for separating the fired porous semiconductor layer from the heat-resistant substrate. Inclusion of the metal oxide (including the metal oxide itself) makes it easier to coat the metal oxide on the porous semiconductor layer (while suppressing the provision of dedicated coating processes and equipment). A solar cell can be mentioned. A further object of the present invention is to provide a manufacturing apparatus for satisfactorily separating the heat-resistant substrate and the porous semiconductor layer.

The present inventors have repeated researches to solve the above problems, and have obtained the following knowledge.
That is, in the method for producing a semiconductor layer as shown in Patent Document 7 above, the undissolved portion of the layer to be dissolved, which has been considered to be a problem (defect) in the past, and a compound (particularly a metal produced from ions generated during dissolution) It has been found that the fact that (oxide) remains on the semiconductor layer, on the contrary, may advantageously improve the photoelectric conversion efficiency when forming the porous semiconductor layer for a dye-sensitized solar cell.

  The dye-sensitized solar cell of the present invention was sandwiched between a working electrode composed of a porous semiconductor layer adsorbing a dye, a flexible resin support that supports the working electrode, a counter electrode, and the working electrode and the counter electrode. A dye-sensitized solar cell comprising a charge transport layer, wherein a metal oxide having a conduction band energy level higher than that of the porous semiconductor layer is dispersed and held in at least a part of the porous semiconductor layer It is.

  The dye-sensitized solar cell of the present invention includes a working electrode comprising a porous semiconductor layer adsorbing a dye, a flexible resin support that supports the working electrode, a counter electrode, and a working electrode and a counter electrode. A dye-sensitized solar cell comprising a charge transporting layer, wherein the porous semiconductor layer is formed on the heat-resistant substrate via the dissolved layer, and further the porous semiconductor layer is peeled off from the heat-resistant substrate, The metal or metal salt contained in the dissolved layer generates a metal oxide having a conduction band energy level higher than that of the semiconductor constituting the porous semiconductor layer, so that the porous semiconductor layer is formed on at least a part of the porous semiconductor layer. It is a dye-sensitized solar cell in which a metal oxide having a higher conduction band energy level is dispersed and held.

  Further, the method for producing a dye-sensitized solar cell of the present invention includes a step of sequentially forming a dissolved layer and a porous semiconductor layer on a heat resistant substrate, and dissolving the dissolved layer to thereby dissolve the heat resistant substrate and the porous semiconductor layer. A dye-sensitized solar cell containing a metal or a metal salt that forms a metal oxide having a conduction band energy level higher than that of a semiconductor constituting the porous semiconductor layer. Is the method.

  Furthermore, the manufacturing apparatus of the dye-sensitized solar cell of the present invention has a structure in which the heat-resistant substrate on which the porous semiconductor layer is formed via the dissolved layer promotes the penetration of the solution (dissolving solution) that dissolves the dissolved layer. The apparatus for manufacturing a dye-sensitized solar cell having a structure, preferably a structure for promoting the penetration of the solution for dissolution, is a stripe-shaped or mesh-shaped groove provided on the surface of the heat-resistant substrate. It is.

  According to the present invention, formation of a porous semiconductor layer on a heat-resistant substrate, which has been used to achieve both high photoelectric conversion efficiency and flexibility, and the formed porous semiconductor layer with a resin support. In a dye-sensitized solar cell to be supported, a porous semiconductor layer formed on a heat-resistant substrate through a dissolved layer containing a metal or a metal salt that generates a metal oxide having a higher conduction band energy level than the porous semiconductor By using this, a dye-sensitized solar cell in which a metal oxide having a higher conduction band energy level than the semiconductor constituting the porous semiconductor layer is dispersed and held in at least a part of the porous semiconductor layer (and further High photoelectric conversion efficiency can be expected).

  Hereinafter, the dye-sensitized solar cell, the manufacturing method thereof, and the manufacturing apparatus of the present invention will be described.

  In this specification, a plurality of working electrodes are formed on one support, and a counter electrode is formed on each of the working electrodes to form a plurality of unit cells, and these unit cells are electrically connected. The dye-sensitized solar cell having the above structure may be referred to as a dye-sensitized solar cell module.

A first embodiment of the present invention (hereinafter referred to as “Embodiment 1”) will be described with reference to FIG.
<Embodiment 1>
First, a heat resistant substrate 1 made of titanium, a stainless alloy, glass, or the like is prepared.

  As the first step (lamination step), the dissolved layer 2, the porous semiconductor layer 3, and the transparent conductive layer 4 are laminated on the heat-resistant substrate 1 (FIG. 1A). The dissolved layer 2 contains a metal or metal salt that generates a metal oxide having a higher conduction band energy level than the porous semiconductor 3, and the porous semiconductor layer 3 is formed by baking at 450 ° C. or higher and 800 ° C. or lower. . The said metal oxide produced | generated from the to-be-dissolved layer 2 may exhibit a film (including the case where it distributes to island shape), or may exist in a granular form. That is, the metal oxide may be generated in a form in which the metal oxide is dispersed and held in the porous semiconductor 3.

  As a second step (separation step), the heat-resistant substrate 1 and the porous semiconductor layer 3 are separated by dissolving the dissolved layer 2. FIG. 1B shows a state in which the heat-resistant substrate 1 in which the layer 2 to be dissolved, the porous semiconductor layer 3 and the transparent conductive layer 4 are laminated is immersed in the solution 5 for dissolution. As will be described later, separation may be performed by spraying the dissolution solution 5 on the heat-resistant substrate 1.

  In this separation step, the metal or metal salt contained in the dissolved layer 2 dissolves into the dissolving solution 5 as metal ions (including complex ions, etc .; the same shall apply hereinafter), and the surface of the porous semiconductor layer 3 Impregnate in the pores. Here, a metal oxide is generated from the metal ions in the dissolving solution 5 by pH change, temperature change, or electric field application of the dissolving solution 5 and dispersed on the surface of the porous semiconductor layer 3 or in the pores thereof. You may perform the process to hold | maintain.

  Further, when the metal salt contained in the dissolved layer 2 is a metal oxide (including a case where the metal salt is converted into an oxide by firing or the like), the entire surface of the porous semiconductor layer 3 and its voids are not dissolved completely. It may be dispersed and held within.

  As a third step (arrangement step), the porous semiconductor layer 3 is disposed on the resin support 6 (FIG. 1C). The resin support 6 in the present invention has flexibility and light transmission, and may be provided with grid electrodes, output terminals, and the like.

  This arrangement step is performed by forming an adhesive layer (or adhesive layer) 11 on the resin support 6 and bonding it to the porous semiconductor layer 3. In addition, although the number of the porous semiconductor layers 3 arrange | positioned on one resin-made support body 6 may be one, it is preferable to arrange | position several and to set it as a dye-sensitized solar cell module.

  The fourth step is a dye adsorption step (not shown). That is, a dye is adsorbed on the porous semiconductor layer 3 to form the working electrode 3a of the dye-sensitized solar cell. The dye, solvent, and adsorption method used will be described later. Before or after the dye adsorption step, a part of the porous semiconductor layer 3 is removed by a method (such as a cutter such as a cutter) or sandblasting, and the transparent conductive layer 4 is exposed to expose the output portion. It is preferable to form it (see FIG. 1D).

  The fifth step is a counter electrode holding step. In this step, the counter electrode 7 having conductivity and catalytic action (action of giving electrons to ions in the charge transport layer 9) is opposed to the working electrode 3a and is held.

  As a preferred configuration, a conductive layer made of ITO or the like and a catalyst layer made of platinum fine particles or the like are provided on a counter electrode support made of a flexible resin to form a counter electrode 7, and the resin support 6 and the counter electrode 7 are formed. An example can be given in which the sealing layer 8 made of a thermoplastic resin, a photo-curable resin, or the like is used to bond together with an arbitrary gap (FIG. 1D).

  The sixth step is a charge transport layer forming step (FIG. 1 (e)). As a preferred configuration, an electrolyte solution (described later) is injected from an electrolyte injection port (not shown) previously opened in either the resin support 6 or the counter electrode 7 to form a charge transport layer 9, and then this electrolyte injection. An example of sealing (sealing) the inlet can be given.

  By such a process, the porous semiconductor layer 3 baked at a high temperature of 450 ° C. or higher is disposed on the resin support 6, and the porous semiconductor layer 3 is formed on at least a part of the porous semiconductor layer 3. It is possible to obtain the dye-sensitized solar cell 100 in which a metal oxide having a conduction band energy level higher than that of the constituent semiconductor is dispersed and held.

<Embodiment 2>
Next, a second embodiment of the present invention (hereinafter referred to as “Embodiment 2”) will be described with reference to FIG.

  As a first step (lamination step), the layer 2 to be dissolved and the porous semiconductor layer 3 are laminated on the heat-resistant substrate 1 (FIG. 2A).

  As the second step, the resin support 6 is arranged. As a preferred configuration, an example in which the resin support 6 on which the transparent conductive layer 4 is formed and the porous semiconductor layer 3 are bonded together using an adhesive layer (or adhesive layer) 21 having light transmittance and conductivity is given. (FIG. 2B).

  The third step is a separation step. FIG. 2C shows a state in which the dissolution solution 5 is separated by spraying. In the second embodiment, the resin support 6 on which the transparent conductive layer 4 is formed is made larger than the porous semiconductor layer 3 to partially remove the porous semiconductor layer 3 as shown in the first embodiment. Thus, the step of exposing the transparent conductive layer 4 becomes unnecessary.

  Hereinafter, the dye adsorption process, the counter electrode holding process, and the charge transport layer forming process are the same as in the first embodiment, and thus the description thereof is omitted.

  Also by such a process, the porous semiconductor layer 3 baked at a high temperature of 450 ° C. or higher is disposed on the resin support 6, and the porous semiconductor layer 3 is formed on at least a part of the porous semiconductor layer 3. Thus, it is possible to obtain a dye-sensitized solar cell in which a metal oxide having a higher conduction band energy level than that of the semiconductor constituting the material is dispersed and held.

  Hereinafter, each component of the dye-sensitized solar cell, the manufacturing method, and the manufacturing apparatus in the present invention will be described in detail.

<Heat resistant substrate>
The heat-resistant substrate 1 in the present invention is a support substrate for laminating the layer to be dissolved 2 and the porous semiconductor layer 3 (in some cases, further a transparent conductive layer 4), and after being separated from the porous semiconductor layer 3 by the separation step, Most of the time it is reused. In addition, the heat-resistant board | substrate 1 does not become a component of a dye-sensitized solar cell.

  The functions required of the heat-resistant substrate 1 are heat resistance (generally 450 ° C. or higher and 800 ° C. or lower) that can withstand the firing temperature of the porous semiconductor layer 3 and resistance to dissolution in solvents, alkalis, acids, and the like in the separation step. . Therefore, specific materials such as aluminum (with sufficient passivation formed on the surface), metal materials such as iron, chromium, nickel, titanium, tungsten, alloys, stainless alloys, quartz glass, silica glass, etc. Examples thereof include ceramics such as glass materials and alumina.

  Moreover, the heat-resistant board | substrate 1 in this invention can change the whole shape and surface shape according to the shape and structure of a dye-sensitized solar cell to manufacture. For example, in order to form a porous semiconductor layer 3 having a curved surface in order to produce a dye-sensitized solar cell having a curved surface, the heat-resistant substrate 1 may be configured to have a curved surface corresponding to the porous semiconductor layer 3. Further, for example, as a preferred method for producing a dye-sensitized solar cell module, a plurality of porous semiconductor layers 3 are formed on one heat-resistant substrate 1, and a resin support 6 is bonded to the heat-resistant substrate 1. A method of arranging a plurality of porous semiconductor layers 3 on the resin support 6 by performing the separation of (see Example 3) can be considered. In this case, the dividing lines of each porous semiconductor layer 3 and / or The structure as a route for promoting the penetration of the dissolving solution 5 into the layer 2 to be dissolved (for example, a stripe-like groove as shown in 31 or a mesh-like groove as shown in 32) is applied to the surface of the heat-resistant substrate 1 It is preferable to form a protrusion 33 or the like on the heat-resistant substrate 1 that is a structure for forming a gap that promotes penetration of the dissolving solution 5 into the dissolution target layer 2 (see FIG. 3). .

<Dissolved layer>
The function required of the layer 2 to be dissolved in the present invention has heat resistance that can withstand the firing temperature of the porous semiconductor layer 3 (although it may be accompanied by chemical changes such as oxidation or decomposition of some components, In addition, the porous semiconductor layer 3 must not be decomposed or burnt down so that the porous semiconductor layer 3 cannot be maintained), and is soluble in solvents, alkalis or acids in the separation step, and in addition, more conductive than the semiconductor constituting the porous semiconductor layer 3 It is necessary to contain a metal or a metal salt for producing a metal oxide having a high band energy level.

When the metal or metal salt is soluble, the layer 2 to be dissolved can be made of the material.
That is, zinc can be used as a metal preferably used in the present invention, and a zinc salt, particularly zinc oxide can be used as a metal salt. This is because zinc and zinc oxide are amphoteric metals and amphoteric compounds that are soluble in many acids and alkalis (bases), and can be easily changed by changing the temperature, pH, or electric field of the solution. In addition, zinc oxide has a conduction band energy level that can be preferably used with respect to titanium oxide that is preferably used as the working electrode 3a of the dye-sensitized solar cell.

  Even if it is difficult to say that the metal salt is soluble (for example, titanium oxide, aluminum oxide, magnesium oxide, etc.), the dissolved layer 2 can be produced by mixing them with a soluble medium.

  For example, although it is generally difficult to say that titanium oxide is highly soluble, a titanium oxide precursor (for example, titanium alkoxide) is added to a layered silicate (for example, trade name Smecton SA, manufactured by Kunipia Kogyo) as a soluble medium. ) Is used to form a layer 2 to be dissolved, and a semiconductor paste (including tin oxide fine particles, for example) is applied to the layer and heated at 450 ° C. to 600 ° C. to form the layer to be dissolved simultaneously with the formation of the porous semiconductor layer 3. The titanium oxide precursor in 2 changes into titanium oxide. Thereafter, the porous silicate layer in the dissolved layer 2 is dissolved with an alkaline solution, whereby the porous semiconductor layer 3 is separated leaving the titanium oxide present at the interface with the dissolved layer 2. According to such a method for producing the layer to be dissolved 2, various metal oxides can be dispersed on the surface of the porous semiconductor layer 3.

  In addition, there is no restriction | limiting in particular in the formation method of the to-be-dissolved layer 2 in this invention, the shape after formation, thickness, etc. For example, the film may be formed to a thickness of about 1 μm to 1 mm using a known method and apparatus such as a coating method, a plating method, a CVD method, a sputtering method, or an SPD method.

<Porous semiconductor layer>
As a material constituting the porous semiconductor layer 3 in the present invention, known semiconductors such as titanium oxide and tin oxide can be used singly or in combination of two or more, but the photoelectric conversion efficiency, stability, and safety can be improved. From the viewpoint, titanium oxide is preferable.

  As a method of forming the porous semiconductor layer 3 on the heat resistant substrate 1, various known methods can be used. However, in the present invention, from the viewpoint of thickening and manufacturing cost, a method of applying a paste containing semiconductor particles on the heat-resistant substrate 1 by a screen printing method, a spin coating method, a doctor blade method or the like and then baking is preferable. .

  The film thickness of the porous semiconductor layer 3 is not particularly limited, but is preferably about 5 μm to 50 μm from the viewpoint of photoelectric conversion efficiency.

In order to improve the photoelectric conversion efficiency, it is necessary to adsorb more dye, which will be described later, to the porous semiconductor layer 3. Therefore, large are preferable porous semiconductor layer 3 is the specific surface ^area, 10 m 2 / g to 200 m approximately ² / g are preferred. The specific surface area is a value measured by the BET adsorption method.

  As the semiconductor particles, semiconductor particles having an appropriate average particle diameter, for example, an average particle diameter of about 1 nm to 500 nm, can be preferably used.

  The firing of the porous semiconductor layer 3 is performed by appropriately adjusting conditions such as temperature, time, atmosphere, and the like according to the type and average particle diameter of the semiconductor particles to be used. For example, it is about 10 minutes to 10 hours, preferably about 20 minutes to 5 hours at 450 ° C. to 800 ° C. in the air or under an inert gas atmosphere. The firing may be performed only once at a single temperature, or may be performed once while changing the temperature, or may be performed twice or more while changing the single temperature or temperature.

<Transparent conductive layer>
In the present invention, the transparent conductive layer 4 uses a conductive metal oxide such as ITO, fluorine-doped tin oxide, niobium-doped titanium oxide, etc., and is well-known such as vacuum deposition, sputtering, PVD, and coating. It is formed by the method. Among these, it is preferable to use ITO by a sputtering method or a PVD method from the viewpoint of light transmittance and electric resistance value.

  Although the film thickness of the transparent conductive layer 4 is not specifically limited, The range of about 0.1 micrometer-5 micrometers is preferable. In addition, you may laminate | stack the transparent conductive material from which a material and a formation method differ in the said range. The sheet resistance value is preferably as low as possible, 300Ω / □ or less, and particularly preferably 20Ω / □ or less.

  In the present invention, the transparent conductive layer 4 may be formed on the resin support 6 or on the porous semiconductor layer 3 or on both of them.

<Solution solution>
The dissolving solution 5 used in the dividing step in the present invention needs to have a property of dissolving the dissolved layer 2 and hardly dissolving the porous semiconductor layer 3. In particular, since zinc is an amphoteric metal and zinc oxide is an amphoteric compound, they are soluble in both alkaline and acidic solutions. Accordingly, it is preferable to use a solution in which the following solute is dissolved in water or an alcohol solvent or a mixed solvent thereof as a solution that satisfies the object of the present invention.

  As the alkali (basic) solute, lithium hydroxide, potassium hydroxide, sodium hydroxide, aqueous ammonia or the like can be used. Further, hydrochloric acid, nitric acid, sulfuric acid and the like can be used as the inorganic acid, and acetic acid, oxalic acid and the like can be used as the organic acid.

<Separation process>
The separation step in the present invention aims to dissolve the layer to be dissolved 2 and separate the porous semiconductor layer 3 from the heat-resistant substrate 1. As a separation method, the heat-resistant substrate 1 on which the layer to be dissolved 2 and the porous semiconductor layer 3 are laminated is immersed in the dissolving solution 5 or sprayed with the dissolving solution 5. The temperature of the dissolving solution 5 at this time is arbitrary as long as the solution does not boil or coagulate, but a preferable temperature range when the aqueous dissolving solution 5 is used is 10 ° C. or more and 90 ° C. or less.

  Moreover, the transparent conductive layer 4 may be laminated on the porous semiconductor layer 3 and both layers may be separated from the heat-resistant substrate 1 at the same time, or the separation step is performed with the resin support 6 attached. May be.

<Precipitation process>
The purpose of the precipitation step in the present invention is to disperse and hold a metal oxide having a higher conduction band energy level on at least a part of the surface (including the pore inner surface) of the porous semiconductor layer 3.

As described in the above <dissolved layer>, the dispersion holding is performed by using a dissolved layer 2 made of a material in which a metal or a metal salt for forming a metal oxide is mixed in a soluble medium, and a paste containing semiconductor fine particles. The porous semiconductor layer 3 is fired after being laminated, and the dissolved layer 2 is dissolved, but when the dissolved layer 2 made of zinc or a zinc salt is used as a particularly preferable metal or metal oxide, However, it is not always necessary to use a soluble medium, and dispersion and retention of the generated zinc oxide is carried out by the following washing steps 1 to 3 (substantially) following the separation step of the porous semiconductor layer 3. be able to.
1. The dissolution solution 5 is finally an alkaline solution having a pH of 8 or more, preferably a pH of 10 or more (even when an acidic solution is used when zinc oxide or metal zinc is dissolved, through a neutralization step thereafter). In the solution, tetrahydroxyzincate ion (Zn (OH) ₄ ²⁻ ) is present in an appropriate concentration (for example, 0.01 mol / l or more and 1 mol / l or less).
2. In a state where the above solution is adhered and / or impregnated on the surface of the porous semiconductor layer 3 after separation (including the inside of the pores), this is treated with water or an alcohol solvent, or a mixed solvent thereof (in some cases Wash with acidic solution). That is, the pH of the alkaline solution is lowered by the cleaning, and zinc hydroxide (Zn (OH) ₂ ) is deposited on the surface of the porous semiconductor layer 3 (including the pore inner surface).
3. The porous semiconductor layer 3 after separation is dried by heating (for example, 30 ° C. or higher and lower than 450 ° C., preferably 50 ° C. or higher and 200 ° C. or lower) (zinc hydroxide changes to zinc oxide).

  Thus, zinc oxide can be dispersed and held on the porous semiconductor layer 3 almost automatically by the steps of separating, washing and drying the porous semiconductor layer 3. Further, the porous semiconductor layer 3 is dissolved by setting the pH of the solution to 8 or less while being immersed in the dissolving solution 5 having a suitable concentration of tetrahydroxyzincate ions at pH 8 or more, preferably pH 10 or more. Zinc hydroxide may be deposited in the working solution 5 (partially deposited on the porous semiconductor layer 3), and then the porous semiconductor layer 3 may be taken out and washed and dried.

  Further, the state of zinc hydroxide can be obtained by increasing the solution temperature (30 ° C. or more and 100 ° C. or less) while the porous semiconductor layer 3 is immersed in the solution 5 for dissolution in which tetrahydroxyzincate ions are present at an appropriate concentration. Zinc oxide may be deposited on the porous semiconductor layer 3 without passing through, and zinc oxide is deposited on the porous semiconductor layer 3 by electrodeposition in a zinc salt solution in which zinc oxide or metallic zinc is dissolved. It may be deposited.

  The concentration of zinc ions and tetrahydroxyzincate ions in the dissolution solution 5 basically depends on the size of the heat-resistant substrate 1 and the thickness of the dissolved layer 2 formed thereon (that is, the amount of metallic zinc or zinc oxide). ) And the amount of the dissolving solution 5, but the concentration can be adjusted by dissolving metal zinc, zinc oxide, or various zinc salts in the dissolving solution 5 in advance or after the dissolved layer 2 is dissolved. Good.

<Resin support>
The separated porous semiconductor layer 3 is disposed on a resin support 6. The resin support 6 in the present invention is flexible and preferably has light transmission properties (for example, it transmits visible light on average 50% or more, preferably 70% or more). Further, when the charge transport layer 9 contains a volatile solvent, it is preferable that the charge transport layer 9 does not dissolve in the solvent and has a gas barrier property against the solvent gas after the volatilization. Specifically, polyester, ethylene / tetrafluoroethylene copolymer, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, polyether ether ketone, polyimide, polyamide imide, polyether imide, acrylic resin, etc. are combined in one or more layers The film is processed into a film having a thickness of about 0.1 mm to 5 mm.

  The resin support 6 according to the present invention collects the transparent conductive layer 4 and grid electrodes (in place of the transparent conductive layer 4 or connected to the transparent conductive layer 4 as necessary, and collects electrons generated at the working electrode 3a as necessary. A metal electrode that takes a shape such as a mesh or stripe having a sufficient aperture ratio), an output terminal (a conductive terminal connected to the working electrode 3a or the transparent conductive layer 4 or the grid electrode, and a dye-sensitized solar cell) Forming a connection portion with an external circuit). Furthermore, in order to hold the porous semiconductor layer 3 and / or to connect the porous semiconductor layer 3 and the transparent conductive layer 4 or the like, an adhesive layer or an adhesive layer may be formed. These adhesive layers or adhesive layers are preferably conductive.

  The grid electrode may be formed of a metal material such as gold, silver, aluminum, titanium, tantalum, tungsten, nickel or an alloy thereof by a known method such as plating, vapor deposition, sputtering, or paste application. The output terminal can also be formed using the same material and method as the grid electrode, and may be formed using solder, copper foil, conductive tape, or the like.

  An epoxy resin, silicone resin, acrylic resin, olefin resin, or the like can be used as the adhesive layer or the adhesive layer. If necessary, a metal material such as gold, silver, titanium, tantalum, tungsten, nickel, Conductivity can be imparted by mixing particles made of ITO, tin oxide (which may be doped with fluorine), zinc oxide, or the like.

<Dye>
As the dye in the present invention, various dyes (metal complexes and organic dyes) having absorption in the visible light region and / or the infrared light region can be used. For example, ruthenium bipyridine dye, azo dye, quinone dye, quinone imine dye, quinacridone dye, squarylium dye, cyanine dye, merocyanine dye, triphenylmethane dye, xanthene dye, porphyrin dye, phthalocyanine And dyes, berylene dyes, indigo dyes, naphthalocyanine dyes, and the like.

These dyes are adsorbed on the porous semiconductor layer 3 to form the working electrode 3a of the dye-sensitized solar cell.
As a method of adsorbing the dye to the porous semiconductor layer 3, for example, a method of applying a dye solution to the porous semiconductor layer 3 (including spray coating) or a case of immersing the porous semiconductor layer 3 in the dye solution (when heated to reflux) Method). It is preferable to immerse the porous semiconductor layer 3 in the dye solution for about 5 minutes to 60 hours, and after taking it out, washing and drying.

  The solvent used in the dye solution is arbitrary as long as it can dissolve the dye. Specifically, alcohols such as ethanol, ketones such as acetone, ethers such as diethyl ether and tetrahydrofuran, nitrogen compounds such as acetonitrile, halogenated aliphatic hydrocarbons such as chloroform, and aliphatic hydrocarbons such as hexane , Aromatic hydrocarbons such as benzene, esters such as ethyl acetate, water and the like. Two or more of these solvents can be used in combination.

The concentration of the dye in the solution can be appropriately adjusted depending on the kind of the dye and the solvent to be used, but in order to improve the adsorption function, the concentration is preferably as high as possible. For example, it is preferably 1 × 10 ⁻⁵ mol / l or more, particularly preferably 5 × 10 ⁻⁵ mol / l to 1 × 10 ⁻² mol / l.

<Counter electrode>
The counter electrode 7 in the present invention constitutes a pair of electrodes facing the working electrode 3a and has flexibility. In addition, it may be conductive (for example, a metal such as gold, platinum, silver, copper, aluminum, nickel, titanium, tantalum, tungsten, an alloy such as stainless steel, or carbon), or a resin. A conductive layer (for example, a metal such as gold, platinum, titanium, tantalum or tungsten, an alloy such as stainless steel, carbon, ITO, tin oxide, or the like) was formed on the support for the counter electrode made of the same material and shape as the support 6. It may be a thing.

  In addition, in order to promote the charge transfer with the charge transport layer 9 (referred to as a catalytic function) on the surface of the counter electrode 7, a catalyst thin film (including a case where the thin film is formed in an island shape) such as platinum or carbon is appropriately formed. To do. For example, the platinum thin film thickness is preferably about 1 nm to 1 μm.

<Charge transport layer>
The charge transport layer 9 in the present invention is an electrolyte-containing layer sandwiched between a resin support 6 and a counter electrode 7 and is composed of a redox species (ion) and a medium capable of holding it. For example, when a liquid is used as a medium, an electrolytic solution is obtained, and when a polymer gel is used, a gel electrolyte is obtained.

  Specifically, the redox species are metals such as iron and cobalt, and halogens such as chlorine, bromine and iodine, and iodine is generally used.

  When iodine is used as a redox species, it is most preferably used in combination with a metal iodide such as lithium iodide, sodium iodide, potassium iodide or calcium iodide.

      Further, an imidazole salt such as dimethylpropylimidazole iodide may be mixed.

  Examples of the solvent for dissolving or dispersing and retaining the redox species include carbonate compounds such as propylene carbonate, nitrile compounds such as acetonitrile, alcohols such as ethanol, water, aprotic polar substances, and the like. Among these, carbonate compounds and nitrile compounds are preferable. Two or more of these solvents can be used in combination. When the volatilization of the solvent becomes a problem, a molten salt may be used instead of the solvent.

  In addition, although the electrolyte concentration in the charge transport layer 9 can be appropriately selected depending on the type of the electrolyte, it is generally preferably in the range of 0.01 mol / l to 1.5 mol / l.

<Sealing layer>
In order to prevent volatilization of the solvent in the charge transport layer 9 and intrusion of water or the like from the outside, it is preferable to form a sealing layer 8 that seals between the resin support 6 and the counter electrode 7 (charge transport). The sealing layer 8 is not necessarily required when there is no concern about the volatilization or outflow of the solvent due to measures such as using a solid material as the medium of the layer 9).

  The sealing layer 8 in the present invention is made of a silicone resin, an ionomer resin, an epoxy resin, a polyisobutylene resin, or the like, and can be used alone or in combination of two or more kinds of materials. In addition, it is preferable to have any property of thermoplasticity, thermosetting property, and photocuring property.

  The pattern of the sealing layer 8 can be formed by a method such as dispenser or screen printing when a paste-like resin is used. When using a sheet-like resin, the sheet-like resin may be cut and patterned using a cutter, a laser, or the like.

<Dye-sensitized solar cell and dye-sensitized solar cell module>
The dye-sensitized solar cell of the present invention is sandwiched between a working electrode 3a disposed on a flexible resin support 6, a counter electrode 7 disposed opposite to the working electrode 3a, and the working electrode 3a and the counter electrode 7. The charge transport layer 9 is formed.

  Here, in order to obtain a dye-sensitized solar cell having an operating voltage (at least 1 V or more, for example, 4 V, 6 V, 12 V, etc.) that can be used for general electric equipment, it is formed on the resin support 6. In a plurality of unit cells, one working electrode 3a (generally a transparent conductive layer 4 connected to the working electrode 3a) and a counter electrode 7 (generally a counter electrode 7) of a unit cell adjacent to the unit cell are configured. Conductive layers) may be connected in series to form a dye-sensitized solar cell module. Specifically, a metal material such as gold, silver, titanium, tantalum, tungsten, nickel, ITO, tin oxide, zinc oxide, or the like in a resin such as a silicone resin, an acrylic resin, an ionomer resin, an epoxy resin, or a polyisobutylene resin Examples include a method of electrically connecting the working electrode 3a and the adjacent counter electrode 7 by adhering each unit cell by using a conductive adhesive mixed with fine particles made of carbon or the like to give conductivity. it can. By using this method, first, the resin support 6 and the counter electrode 7 can be firmly bonded. And reliable separation between unit cells can be performed. Furthermore, electrical connection between unit cells can be made. Can be obtained at the same time.

Hereinafter, the present invention will be described in more detail with reference to examples.
<Example 1>
As a first embodiment of the present invention, an example of zinc oxide generation by pH change of the dissolving solution 5 will be described with reference to FIG.

  A 200 mm square (2 mm thick) glass substrate (manufactured by Nippon Sheet Glass Co., Ltd.) was used as the heat-resistant substrate 1, and after washing, a 1 μm thick zinc oxide layer (dissolved layer 2) was formed on the entire surface by sputtering.

  A commercially available titanium oxide paste (manufactured by Solaronix, trade name: Ti-Nanoxide D / SP, average particle size: 13 nm) is applied to the heat-resistant substrate 1 by 1 cm square by screen printing, and baked at 500 ° C. for 20 minutes. Thus, a porous semiconductor layer 3 having a film thickness of 30 μm was obtained (25 pieces were formed as shown in FIG. 4A. However, the working electrodes 3a were used individually one by one).

  Next, the resin support 6 is disposed. A 3 cm square, 125 μm thick ITO terephthalate film with ITO (trade name OTEC, manufactured by Tobi Co., Ltd.) and ITO ink (manufactured by Sumitomo Metal Mining Co., Ltd., trade name X-100) with a 2 cm square final film thickness 4 Screen printing was performed so that the thickness was ˜5 μm, and this was overlaid on the porous semiconductor layer 3 formation region on the heat-resistant substrate 1, and both were bonded by pressing at 80 ° C. for 20 minutes (FIG. 4B). Here, the ITO previously formed on the film is the transparent conductive layer 4, and the applied ITO ink works as the conductive adhesive 41.

  A 1.5 mol / l sodium hydroxide aqueous solution (dissolution solution 5) was sprayed on the heat-resistant substrate 1 with the laminated film to separate the heat-resistant substrate 1 and the porous semiconductor layer 3 (FIG. 4C). Here, zinc in the dissolved layer 2 is dissolved in the dissolving solution 5 as tetrahydroxyzincate ions.

  Next, the separated resin support 6 (with the porous semiconductor layer 3) is spray-washed with pure water and dried at 100 ° C. for 1 hour, whereby porous oxidation partially covered with granular zinc oxide is performed. A titanium layer was obtained. Here, the presence of zinc oxide was confirmed by a digital microscope (VHX200 manufactured by Keyence Corporation) and a thin film X-ray diffractometer (RINT2100 manufactured by Rigaku Corporation).

Below, the principle of this dispersion | distribution holding | maintenance is demonstrated.
First, the surface of the porous semiconductor layer 3 and the pores before the cleaning step are adhered and impregnated with the dissolving solution 5 containing tetrahydroxyzincate ions.

  Here, when the porous semiconductor layer 2 is washed with water, alcohol or the like (including an acidic solution in some cases) in order to remove excess alkali components, the surface and pores of the porous semiconductor layer 2 are impregnated. The alkaline solution is diluted (neutralized in some cases) and the pH is lowered, so that tetrahydroxyzincate ions are precipitated as zinc hydroxide, and some of them are formed on the surface of the porous semiconductor layer 2 and the pores. Held in. Zinc hydroxide changes to zinc oxide even at room temperature (25 ° C.), but changes more rapidly to zinc oxide by heating for drying the porous semiconductor layer 3 (for example, 30 ° C. or higher and lower than 450 ° C.). .

  As a result, it is possible to realize a structure in which a metal oxide (zinc oxide in the first embodiment) having an energy level higher than the energy level of the conduction band is dispersed and held in at least a part of the porous semiconductor layer 2. .

Next, N719 (Ru535bisTBA manufactured by Solaronix) was dissolved in ethanol to a concentration of 3 × 10 ⁻⁴ mol / l to prepare a dye solution. The resin support 6 on which the porous semiconductor layer 3 was formed in this dye solution was held at 25 ° C. for 120 hours to adsorb the dye to the porous semiconductor layer 3. Then, it wash | cleaned and dried with ethanol and it was set as the working electrode 3a.

  The same 3 cm square polyethylene terephthalate film with ITO as the resin support 6 is sputtered with platinum (50 nm) as a counter electrode 7, and this and the resin support 6 with the working electrode 3 a are thermoplastic having a thickness of 50 μm. A film (made by Mitsui DuPont, trade name High Milan) was attached as a sealing layer 8 on the outer periphery of the support by a vacuum press at 100 ° C. for 1 hour. Then, the charge transport layer 9 was formed by injecting an electrolyte solution from an electrolyte injection port previously opened in the counter electrode 7. This electrolytic solution is an acetonitrile solution of lithium iodide (0.1M), iodine (0.01M), t-butylpyridine (0.5M), and dimethylpropylimidazolium iodide (0.6M).

Finally, a dye-sensitized solar cell was manufactured by sealing the electrolyte injection port with high Milan.
When the obtained dye-sensitized solar cell was subjected to IV characteristic evaluation using a solar simulator (Wacom Co., Ltd., light quantity: 100 mW / cm ² ), the short-circuit current (J _SC ) was 15.9 mA / cm ² , open. The voltage (V _OC ) was 0.74 V, the fill factor (FF) was 0.67, and the photoelectric conversion efficiency (η) was 7.9%.
<Comparative example>
As a comparative example, an example of a dye-sensitized solar cell that does not use zinc oxide is shown.

  Instead of the zinc oxide layer in Example 1, 1 μm of aluminum was sputtered to form a layer 2 to be dissolved.

  Then, the porous semiconductor layer 3, the transparent conductive layer 4, and the resin support 6 were formed according to Example 1, and this was immersed in dilute sulfuric acid to dissolve the dissolved layer 2. The separated resin support 6 (with the porous semiconductor layer 3) was sufficiently washed with dilute sulfuric acid and pure water so that no aluminum ions remained, and then dried at 100 ° C. for 1 hour.

Furthermore, dye adsorption according to Example 1, bonding of the counter electrode 7, formation of the charge transport layer 9 and sealing of the electrolyte inlet were performed, and IV characteristics were evaluated using a solar simulator (same as Example 1). However, the short-circuit current (J _SC ) was 14.7 mA / cm ² , the open-circuit voltage (V _OC ) was 0.69 V, the fill factor (FF) was 0.65, and the photoelectric conversion efficiency (η) was 6.6%. It was. It is considered that the reason why the photoelectric conversion efficiency is lower than that of Example 1 is that zinc oxide is not formed on the porous semiconductor layer 3 made of titanium oxide.

<Example 2>
As a second embodiment of the present invention, an example of generation of zinc oxide due to a temperature change of the dissolving solution 5 will be described. That is, it is known that zinc oxide precipitates directly (without going through zinc hydroxide) from an alkaline solution by raising the temperature of an alkaline solution (for example, an aqueous solution or an alcohol-containing aqueous solution) containing tetrahydroxyzincate ions. ing. The reaction formula is Zn (OH) ₄ ²⁻ (heating) → ZnO + H ₂ O + 2OH ⁻
It is. When this reaction is used, the heat-resistant substrate 1 in which the layer to be dissolved 2 and the porous semiconductor layer 3 are laminated is immersed in the dissolution solution 5 to dissolve the layer to be dissolved 2 (if necessary, tetrahydroxyzinc acid The pH of the solution may be adjusted so that ions are generated), and the dissolution solution 5 is heated after removing the heat-resistant substrate 1 (optional if the heating temperature is room temperature or higher, preferably 30 ° C. or higher and 100 The heating time is preferably from 30 ° C. to 95 ° C. The heating time is preferably from about 30 minutes to 5 hours, so that zinc oxide can be coated on the porous semiconductor layer 3.

  First, a 200 mm square (thickness 2 mm) glass substrate manufactured by Nippon Sheet Glass Co., Ltd. was used as the heat-resistant substrate 1, and a 1 μm thick metal zinc layer was deposited as the melted layer 2 after cleaning. Here, 1 cm square screen printing was performed using the same titanium oxide paste as in Example 1, and the porous semiconductor layer 3 having a thickness of 30 μm was obtained by baking at 500 ° C. for 20 minutes.

  The heat-resistant substrate 1 with the porous semiconductor layer 3 and a 3 cm square polyethylene terephthalate film with ITO (resin support 6) were bonded together according to Example 1. This was immersed in a 0.5 mol / l nitric acid aqueous solution (dissolution solution 5) to dissolve the layer 2 to be dissolved. The temperature of the nitric acid aqueous solution at the time of dissolution was 25 ° C.

  Zinc nitrate is added to the nitric acid aqueous solution from which the heat-resistant substrate 1 has been removed (finally adjusted so that tetrahydroxyzincate ions in the solution are about 0.1 mol / l), and 1.5 mol / l ammonia water is added here. The solution was stirred gently while adding dropwise. A white precipitate (zinc hydroxide) was initially observed, but a transparent alkaline solution was obtained. The resin support 6 with the porous semiconductor layer 3 was immersed in this alkaline solution, and placed in a reflux state at 90 ° C. for 1 hour. Thereafter, the resin support 6 with the porous semiconductor layer 3 was taken out of the alkaline solution, washed with pure water, and dried to obtain a porous titanium oxide layer coated in an island shape with a zinc oxide coating. Here, the presence of zinc oxide was confirmed by a digital microscope (VHX200 manufactured by Keyence Corporation) and a thin film X-ray diffractometer (RINT2100 manufactured by Rigaku Corporation).

  Furthermore, dye adsorption according to Example 1, bonding of the counter electrode 7, formation of the charge transport layer 9 and sealing of the electrolyte inlet were performed, and IV characteristics were evaluated using a solar simulator (same as Example 1). However, performance equivalent to that of the dye-sensitized solar cell of Example 1 was obtained.

<Example 3>
As a third embodiment of the present invention, an example of zinc oxide generation by electrodeposition will be described with reference to FIG. That is, an electrodeposition reaction from an aqueous zinc salt solution is known as a zinc oxide formation reaction. For example, in the case of zinc nitrate (Zn (NO ₃ ) ₂ ),
Zn ²⁺ + NO ₃ ⁻ + 2e ⁻ → ZnO + NO ₂ ⁻ (E ₀ = + 0.246 V vs. SCE)
It is. If this reaction is used, after disposing the transparent conductive layer 4 and the resin support 6 on the layer to be dissolved 2 and the porous semiconductor layer 3 laminated on the heat-resistant substrate 1, the solution 5 ( In this embodiment, an acid aqueous solution such as nitric acid is preferable), the layer 2 to be dissolved is dissolved, and the heat-resistant substrate 1 is removed, and then a voltage is applied to the transparent conductive layer 4 so that the porous semiconductor 3 is coated. Zinc oxide can be deposited on the substrate. The applied voltage is -0.5 V to -1.5 V (vs. SCE), and the electrodeposition time is preferably about 10 minutes to 2 hours.

  First, a 100 mm square (2 mm thick) glass substrate having grooves 51 as shown in FIG. 5A was used as the heat resistant substrate 1, and a 1 μm thick metal zinc layer (dissolved layer 2) was formed by sputtering. .

Furthermore, using the same titanium oxide paste as in Example 1, screen printing was performed in a stripe shape having a width of 6 mm, a length of 90 mm, and 10 pieces (interval between application areas of 2 mm), and baked at 500 ° C. for 20 minutes, resulting in a film thickness of 30 μm. The porous semiconductor layer 3 was laminated (FIG. 5A).
As a resin support 6, a 100 mm square polyethylene terephthalate film with ITO (except for the size is the same as in Example 1) was prepared, and a photosensitive resist was used to make ITO 7 mm wide, 95 mm long, 10 (coated area) Pattern etching was performed in the form of stripes having an interval of 1 mm).

  Further, ITO ink (same as Example 1) was screen-printed in the same shape as the etched ITO to form an adhesive layer 52. This ITO ink application region and the porous semiconductor layer 3 on the heat-resistant substrate 1 were superposed and bonded together by pressing at 80 ° C. for 20 minutes (FIG. 5B). This was immersed in a 0.5 mol / l nitric acid aqueous solution (dissolution solution 5) to dissolve the dissolved layer 2 (FIG. 5C).

  After the heat-resistant substrate 1 is taken out, zinc nitrate is added to the dissolving solution 5 (the final adjustment is made so that the zinc ions in the solution are about 0.1 mol / l), and the solution is heated to 70 ° C. Here, a platinum electrode and a reference electrode are put in the solution, and a voltage (−0.7 V vs. SCE) is applied for 1 hour by connecting the stabilized power supply 53 to the ITO on the resin support 6 (FIG. 5C). Then, the porous titanium oxide layer partially covered with the microcrystalline zinc oxide was obtained by drying at 150 ° C. for 1 hour. Here, the presence of zinc oxide was confirmed with a digital microscope (VHX200 manufactured by Keyence Corporation) and an X-ray diffractometer (RINT2100 manufactured by Rigaku Corporation).

Next, dye adsorption was performed according to Example 1 to obtain a working electrode 3a.
As the counter electrode 7, the same polyethylene terephthalate film with ITO as in the resin support 6 is etched in a stripe shape, and a platinum thin film is laminated on the ITO, and the resin support 6 and the counter electrode 7 are attached as follows. In this way, they were bonded together.

A thermosetting resin (manufactured by Three Bond, product name Three Bond 1152) and titanium particles (manufactured by Toho Titanium Co., Ltd., product name TC-450: average particle size 45 μm) are mixed at a volume ratio of 10% to create a conductive adhesive 54 did.
This conductive adhesive 54 is screen-printed in a stripe shape with a width of 0.8 mm on the ITO of the counter electrode 7 (the end portion on the long side of the stripe), and 50 μm thick high Milan is sealed on the outer periphery of the resin support 6. Arranged as layer 8. In this state, the resin support 6 and the counter electrode 7 were superposed and vacuum-pressed at 100 ° C. for 1 hour to bond both substrates. Thereafter, the same electrolyte solution as that in Example 1 was injected from an electrolyte inlet previously opened in the counter electrode 7 to form the charge transport layer 9. As a result, one working electrode 3 a and the ITO with the platinum thin film opposed thereto form a unit cell, and the unit cells are connected in series by the conductive adhesive 54.

  Finally, the electrolyte injection port was sealed to produce a dye-sensitized solar cell module 500 (10 unit cells connected in series) (FIG. 5D).

When the obtained dye-sensitized solar cell module 500 was subjected to IV characteristic evaluation using a solar simulator (same as in Example 1), the short-circuit current (J _SC ) was 15.7 mA / cm ² , the open-circuit voltage ( V _OC ) was 7.1 V, the fill factor (FF) was 0.66, and the photoelectric conversion efficiency (η) was 7.0%.

It is the schematic which shows an example of the manufacturing process of the dye-sensitized solar cell in this invention. It is the schematic which shows the other example of the manufacturing process of the dye-sensitized solar cell in this invention. It is the schematic which shows an example of the surface shape of the heat-resistant board | substrate in this invention. FIG. 3 is a schematic view showing a production process of a dye-sensitized solar cell in Example 1. FIG. 6 is a schematic view showing a production process of a dye-sensitized solar cell module in Example 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat-resistant board | substrate 2 To-be-dissolved layer 3 Porous semiconductor layer 3a Working electrode (porous semiconductor layer which the pigment | dye adsorbed)
4 Transparent conductive layer 5 Dissolution solution 6 Resin support 7 Counter electrode 8 Sealing layer 9 Charge transport layer

Claims (9)

Dye-sensitized sun comprising a working electrode comprising a porous semiconductor layer adsorbing a dye, a flexible resin support that supports the working electrode, a counter electrode, and a charge transport layer sandwiched between the working electrode and the counter electrode A battery,
The porous semiconductor layer is formed by peeling a porous semiconductor layer formed on a heat resistant substrate via a dissolved layer from the heat resistant substrate,
A metal or metal salt contained in the dissolved layer generates a metal oxide having a higher conduction band energy level than the semiconductor constituting the porous semiconductor layer,
At least a portion, color Motozo sensitized solar cell metal oxide high conduction band energy level than the porous semiconductor layer is characterized in that it is dispersed and held in the porous semiconductor layer. Dye-sensitized sun comprising a working electrode comprising a porous semiconductor layer adsorbing a dye, a flexible resin support that supports the working electrode, a counter electrode, and a charge transport layer sandwiched between the working electrode and the counter electrode A battery manufacturing method comprising:
A step of sequentially forming a dissolved layer and a porous semiconductor layer on a heat-resistant substrate;
A separation step of separating the heat-resistant substrate and the porous semiconductor layer by dissolving the dissolved layer,
The method for producing a dye-sensitized solar cell, wherein the dissolved layer contains a metal or a metal salt that generates a metal oxide having a conduction band energy level higher than that of a semiconductor constituting the porous semiconductor layer. The method for producing a dye-sensitized solar cell according to claim 2 , further comprising a disposing step of disposing at least one porous semiconductor layer after the separating step on the resin support. 3. The dye enhancement according to claim 2 , further comprising a step of adhering or sticking the resin support to one or more of the porous semiconductor layers formed on the heat-resistant substrate before the separation step. A method for producing a solar cell. The method for producing a dye-sensitized solar cell according to any one of claims 2 to 4 , wherein the dissolved layer contains zinc oxide or metallic zinc. The method for producing a dye-sensitized solar cell according to any one of claims 2 to 5 , further comprising a precipitation step of dispersing and holding zinc oxide on the surface of the porous semiconductor layer after the stacking step. The precipitation step, the said porous semiconductor layer in contact with the solution of the dissolved layer, before drying to claim 6, wherein a is to heat at a temperature below 30 ° C. or higher 100 ° C. A method for producing a dye-sensitized solar cell. The method for producing a dye-sensitized solar cell according to claim 6 , wherein the deposition step is electrodeposition on the porous semiconductor layer in a solution in which the layer to be dissolved is dissolved.   Dye-sensitized sun comprising a working electrode comprising a porous semiconductor layer adsorbing a dye, a flexible resin support that supports the working electrode, a counter electrode, and a charge transport layer sandwiched between the working electrode and the counter electrode An apparatus for manufacturing a battery, wherein the heat-resistant substrate for forming the porous semiconductor layer through the layer to be dissolved is a stripe-shaped or mesh-shaped groove provided on a surface thereof, and the layer to be dissolved is dissolved. An apparatus for producing a dye-sensitized solar cell, characterized in that the penetration of a solution to be promoted is promoted.

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