JP2011238482A - Photoelectric conversion element, manufacturing method thereof, and polymer electrolyte solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive and highly efficient dye-sensitized photoelectric conversion element, a manufacturing method thereof, and a polymer electrolyte solar cell using the photoelectric conversion element.SOLUTION: In the photoelectric conversion element containing a polymer electrolyte 2, a metal layer 1, and dye molecules, the photoelectric conversion element contains at least one kind selected from a group of quinones, alloxazines, and ferrocenes, the metal layer is in contact with the polymer electrolyte and formed on the surface and/or the inside of the polymer electrolyte, and the dye molecules are adsorbed to the metal layer.

Description

  The present invention relates to a photoelectric conversion element useful for solar cells and the like, and in particular, a photoelectric conversion element having a novel structure using a dye molecule, a method for producing the photoelectric conversion element, and further using the photoelectric conversion element. The present invention relates to a polymer electrolyte solar cell.

  In recent years, the use of fossil fuels such as oil and coal has been a concern as a cause of global warming, and the importance of alternative energy has increased. Solar cells that produce electricity from sunlight are an important source of alternative energy. As one, it is attracting attention.

  Under such circumstances, photoelectric conversion elements used for solar cells and the like have been actively researched and developed in recent years by dye sensitization methods. This has a basic structure in which a complex dye or organic dye is fixed to the surface of a porous compound semiconductor (for example, porous titanium oxide) thinned on a transparent conductive substrate (electrode). It is driven by absorbing electrons and moving electrons to the conduction band of the semiconductor, and is intended to use the visible light region in particular. In order to improve the performance of a photoelectric conversion element using such a dye, it is possible to reliably fix the dye and increase the absolute amount of the dye to be fixed.

  However, photoelectric conversion elements using dyes that have been developed so far are those in which a functional group such as thiol is introduced into the dye and the dye is self-assembled into a planar electrode formed of a metal such as gold. The amount of the dye to be immobilized was limited.

  In Patent Document 1, in order to solve such a problem, after depositing thin metal fine particles on a conductive substrate (electrode), a metal-sulfur is formed on the surface of the metal fine particles by a sulfur compound having a dye molecule. A method is disclosed in which a dye is immobilized through bonding, an effective area as an electrode is increased, and dye sensitization efficiency is improved. However, even when this method is used, sufficient performance is not obtained as a photoelectric conversion element.

  Patent Document 2 discloses a substrate composed of a transparent conductive thin film, metal fine particles, a photoelectrode in which a photosensitizer is adsorbed on semiconductor fine particles such as titanium oxide, and a solar cell including this photoelectrode. ing. High energy conversion efficiency as a solar cell is expected by adsorbing a photosensitizer to metal fine particles, but titanium oxide and transparent conductive thin film used as semiconductor fine particles are high in cost and put to practical use. Has a problem.

JP 2002-270865 A JP2007-335222A

  Accordingly, the object of the present invention is to use a metal that is inexpensive without using a transparent conductive substrate or titanium oxide, and increases the amount of adsorption / fixation of dye molecules to the metal layer to improve dye sensitization efficiency. The layer is formed into a fine structure (including nanostructures) such as fractals, the surface area (effective area) is increased as an electrode, the photoelectric conversion efficiency by the surface plasmon resonance (SPR) effect is enhanced, and specific electrons By containing an acceptor and a redox pair, a photoelectric conversion element capable of generating a practical level of photocurrent by only light irradiation without an electromotive force, and a method for producing the photoelectric conversion element, Is to provide a polymer electrolyte solar cell using the photoelectric conversion element.

  In order to achieve the above object, the present inventors have intensively studied the configuration of the photoelectric conversion element. As a result, the present inventors have found that the above problem can be solved by using the following photoelectric conversion element, and have completed the present invention. .

  That is, the photoelectric conversion element of the present invention is a photoelectric conversion element including a polymer electrolyte, a metal layer, and a dye molecule, and the photoelectric conversion element is selected from the group consisting of quinones, alloxazines, and ferrocenes. Containing at least one selected, wherein the metal layer is in contact with the polymer electrolyte, and the metal layer is formed on the surface and / or inside of the polymer electrolyte, and the dye molecule Is adsorbed on the metal layer.

  The photoelectric conversion element of the present invention preferably further contains viologens.

  In the photoelectric conversion element of the present invention, the dye molecule is preferably a sulfur-containing compound.

  In the photoelectric conversion element of the present invention, the polymer electrolyte is preferably an ion exchange resin.

  The photoelectric conversion element of the present invention preferably contains an electrolyte salt.

  The photoelectric conversion element of the present invention preferably contains an ether group-containing compound having a molecular weight of 50 to 400.

  In the photoelectric conversion element of the present invention, the metal layer preferably forms a pair.

  In the photoelectric conversion element of the present invention, it is preferable that one metal layer forming the pair and the other metal layer are formed of different metals.

  In the photoelectric conversion element of the present invention, the metal microstructure constituting the metal layer has a rich region toward the outside of the polymer electrolyte, and the polymer electrolyte toward the center of the polymer electrolyte. However, it is preferable to have a rich region.

  Moreover, it is preferable that the polymer electrolyte type solar cell of this invention is equipped with the said photoelectric conversion element.

  The method for producing a photoelectric conversion element of the present invention is a method for producing the photoelectric conversion element, wherein the metal is formed on the surface and / or inside of the polymer electrolyte by an electrolytic plating method and / or an electroless plating method. A step of forming a layer, a step of adsorbing dye molecules to the metal layer, and a step of swelling the metal layer adsorbed with the polymer electrolyte and the dye molecules with a solvent or a solution. Is preferred.

  In the method for producing a photoelectric conversion element of the present invention, it is preferable that the metal layer forms a pair, and one metal layer forming the pair and the other metal layer are formed by different methods.

  In the method for producing a photoelectric conversion element of the present invention, the electroless plating method includes an adsorption step in which a metal complex is adsorbed on the polymer electrolyte, and a reducing agent solution is brought into contact with the polymer electrolyte on which the metal complex is adsorbed. A reduction step of forming a layer.

  The photoelectric conversion element of the present invention can be produced at low cost without using an expensive material such as a transparent conductive substrate or titanium oxide, and is excellent in workability and useful. The photoelectric conversion element forms a metal layer having a fine structure (including a nanostructure) in order to increase the amount of adsorption / fixation of dye molecules to the metal layer and improve dye sensitization efficiency. In addition, by having the fine structure, the surface area (effective area) of the electrode is increased, and coupled with this, the photoelectric conversion efficiency can be enhanced by the surface plasmon resonance (SPR) effect. Furthermore, by containing a specific electron acceptor or a redox pair, a practical photocurrent can be generated only by light irradiation without an electromotive force, which is useful. In addition, the polymer electrolyte solar cell using the photoelectric conversion element emits light (light rays) not only in the visible region but also in the near infrared region, compared to conventional solar cells using a transparent conductive electrode. Can be used effectively, and the charge separation action is promoted by containing the fine structure of the metal layer and the accompanying SPR effect, as well as specific electron acceptors and redox couples, The photocurrent can be increased and is useful. In addition, the photoelectric conversion element is useful not only for a solar cell excellent in photoelectric conversion efficiency but also for use as an optical sensor or the like.

SEM photograph of the polymer electrolyte and metal layer used in the photoelectric conversion element of the present invention (magnification 800 times) Schematic diagram of a photoelectric conversion device manufacturing apparatus having an asymmetric metal layer Schematic diagram of a photoelectric conversion device manufacturing apparatus having an asymmetric metal layer

<Method for producing photoelectric conversion element>
The manufacturing method of the photoelectric conversion element of this invention can be enforced by the process of the following (i)-(iv). Note that the following (i) pretreatment step is optional.

  The method for producing a photoelectric conversion element of the present invention includes: (i) a pretreatment step in which a polymer electrolyte is swollen with a solvent; and (ii) an electrolytic plating (electroplating) method and / or an electroless plating method. A step of forming the metal layer on and / or inside a polyelectrolyte, (iii) a step of adsorbing dye molecules to the metal layer, and (iv) of the polyelectrolyte and the dye molecules. And a step of swelling the adsorbed metal layer with a solvent or a solution. In particular, the electroless plating method includes an adsorption step in which a metal complex is adsorbed on the polymer electrolyte, and a reduction step in which a reducing agent solution is brought into contact with the polymer electrolyte on which the metal complex is adsorbed to form a metal layer. It is preferable. Below, the manufacturing method of the photoelectric conversion element of this invention is demonstrated in detail.

(I) Pretreatment step In the method for producing a photoelectric conversion element of the present invention, as a pretreatment step performed in advance of a plating method (electrolytic plating method and / or electroless plating method), the polymer electrolyte (for example, A swelling step of swelling the ion exchange resin) can be performed. In the swelling step, a swelling solvent (swelling solvent) is permeated into the polymer electrolyte. The swelling of the polymer electrolyte in a swollen state is preferably 10% or more, more preferably 25% or more with respect to the thickness of the polymer electrolyte in a dried state. By passing through the swelling step, in the adsorption step of the metal complex (including metal ions) in the plating method, the metal complex easily penetrates and adsorbs from the surface of the polymer electrolyte, and in the reduction step However, it is considered that the reducing agent in the reducing agent solution is easily adsorbed from the surface of the polymer electrolyte.

(Polymer electrolyte)
The polymer electrolyte is not particularly limited, and a known one can be used. Since the polymer electrolyte does not use a transparent conductive electrode using ITO (indium tin oxide) or the like, the polymer electrolyte is excellent in flexibility and compared with conventional photoelectric conversion elements and solar cells using the same. Therefore, the expansion of application fields can be expected. The polymer electrolyte is not particularly limited as long as a metal complex (including metal ions) can be sufficiently adsorbed. For example, it is preferable to use an ion exchange resin, a fluorine ion exchange resin, carbon It is more preferable to use a system ion exchange resin or the like, and it is particularly preferable to use a fluorine ion exchange resin. The fluorine-based ion exchange resin is not particularly limited, and a known resin can be used, and a resin introduced with a hydrophilic functional group such as a sulfonic acid group or a carboxyl group can be used. As specific examples of the fluorine-based ion exchange resin, perfluorocarboxylic acid resin and perfluorosulfonic acid resin can be used. For example, Nafion resin (perfluorosulfonic acid resin, manufactured by DuPont), Flemion (perfluorocarboxylic acid) Resin or perfluorosulfonic acid resin (Asahi Glass Co., Ltd.) can be used. When the ion exchange resin contains an electrolyte salt as a photoelectric conversion element, the degree of freedom in selecting the ion species of the electrolyte salt is large, and the range of combinations according to applications and characteristics can be widened. More preferably, it is a resin. The polymer electrolyte can be used in a shape suitable as a photoelectric conversion element obtained by the plating method, and may be a film shape, a plate (sheet) shape, a cylinder (cylindrical) shape, a columnar shape, a tubular shape, or the like. Can be used.

  For example, when the ion exchange resin is a perfluorocarboxylic acid resin or perfluorosulfonic acid resin that is a fluorine-based ion exchange resin, the ion exchange capacity of the perfluorocarboxylic acid resin or perfluorosulfonic acid resin is as follows: 1.0 to 1.8 meq / g is preferable, and 1.2 to 1.6 meq / g is more preferable. By using a fluorine-based ion exchange resin within the above range, the film forming characteristics and the plating characteristics (suitability) are excellent and useful.

  The swelling solvent is a solvent that can swell the crosslinked polymer (resin etc.) well, and varies depending on the type of polymer electrolyte. For example, methanol, ethanol, propanol, hexafluoro-2-propanol , Diethylene glycol, glycerin, 2-methoxyethanol, acetone, dimethylformamide, N-methylformamide and the like are preferably used. In particular, in the swelling step, when the polymer electrolyte uses a fluorinated ion exchange resin such as a perfluorocarboxylic acid resin or a perfluorosulfonic acid resin, it contains methanol and / or ethanol, and further contains another solvent. It is preferable to swell the polymer electrolyte (ion exchange resin) by infiltrating a mixed solvent. These solvents are particularly preferable because they easily swell, are easy to handle, and have good workability. Also, by swelling the polymer electrolyte, the degree of crystallinity of the polymer electrolyte is lowered, and in particular, the entanglement of the side chain having a functional group in the polymer electrolyte is alleviated, and the degree of freedom of segment motion about the side chain is reduced. Increase.

  In the pretreatment step, conditions such as temperature and immersion time are not particularly limited, but the temperature is preferably 20 ° C. or higher for efficient swelling, more preferably 30 ° C. or higher. Preferably, it is 35-55 degreeC.

  In the pretreatment step, a method of immersing a polymer electrolyte (for example, an ion exchange resin) in a solvent for swelling may be used, or a method of applying the solvent to the surface of the polymer electrolyte may be used. Although it is good, it is preferable to use a method of immersing the polymer electrolyte because the operation is easy.

(Ii) Plating method The plating method in the present invention is not particularly limited, and an electrolytic plating method (electroplating method), electroless plating, or the like can be used. The electrolytic plating method is useful because the plating film thickness can be easily adjusted by adjusting the amount of energization. Further, the electroless plating method can be applied to a polymer electrolyte or the like, and a metal layer (metal plating layer) having a uniform film thickness can be obtained even for a complicated material shape (polymer electrolyte or the like). Therefore, it is preferable.

<Electroless plating method>
(Adsorption process)
In the method for producing a photoelectric conversion element of the present invention, when an electroless plating method is adopted, as the adsorption step, the metal complex solution may be applied to the polymer electrolyte, but the polymer electrolyte is immersed in the metal complex solution. This is preferable because the operation is easy.

  As long as the adsorption step is a step of adsorbing a metal complex to the polymer electrolyte, conditions such as temperature and immersion time are not particularly limited. More preferably, it is 30 degreeC or more, Most preferably, it is 35-55 degreeC. Moreover, the said adsorption process may contain the solvent used in the said pre-processing process in a metal complex solution, in order for a metal complex to adsorb | suck easily in a polymer electrolyte. Here, the metal complex solution in the adsorption step is particularly limited as long as the metal layer (metal electrode) formed by reduction contains a metal complex that can function as an electrode. However, for example, a chelated metal complex using a chelating agent such as phenanthroline metal complex and ethylenediaminetetraacetic acid (EDTA) can be used. Although it does not specifically limit as a density | concentration of the said complex solution, For example, what is 0.1-2.0 weight% is preferable, 0.2-1.5 weight% is more preferable, 0.3-1.1 weight% % Is particularly preferred. The metal complex is a metal that can ensure conductivity and is not particularly limited as long as it is a metal complex that can be used as an electroless plating method, but contains a metal that can exhibit the SPR effect. Use of a complex is a more preferred embodiment.

(Reduction process)
The reduction step in the present invention is a step of reducing the metal complex adsorbed in the polymer electrolyte by the adsorption step and precipitating the metal. In the reduction step in the present invention, a reducing agent solution having one concentration can be used, and a reducing agent solution having a plurality of concentrations can be used. When a multi-concentration reducing agent solution is used, as the reducing step, a high-concentration reducing agent solution is brought into contact with the low-concentration reducing agent solution step by step. Is, for example, preferably 0.005 to 10% by weight, more preferably 0.008 to 8% by weight, and particularly preferably 0.01 to 6% by weight. The reducing agent solution having a concentration within the above range is divided into a plurality of times (multiple concentrations) from a low concentration to a high concentration in stages (gradually), to a polymer electrolyte adsorbed with a metal complex. By contacting, a metal layer composed of fine metal particles (metal microstructure) having an extremely small average particle diameter can be formed, which is useful. In addition, by bringing a reducing agent solution in a low concentration into contact, a dense region with a high density of metal microstructure is formed in the vicinity of the polymer electrolyte interface, and the concentration of the reducing agent solution can be further increased. By adjusting the number of contact times of the solution, adjusting the temperature conditions at the time of contact, etc., forming regions (layers) with different metal microstructure density (here, low density) across multiple layers Can do. In the present invention, a dense metal layer (including a nanostructured metal electrode) is formed by contacting a high concentration reducing agent solution stepwise (gradually) from the low concentration reducing agent solution. can do. Since such a metal layer has a very large specific surface area and increases the effective area as an electrode, the amount of dye molecules adsorbed and immobilized on the metal layer can be increased to improve dye sensitization efficiency. In combination with this, the photoelectric conversion efficiency due to the SPR effect can be enhanced.

  In the photoelectric conversion element of the present invention, since the metal layer is formed on the polymer electrolyte in this way, the interface between the metal layer and the polymer electrolyte is not always clear, and the vicinity of the outer side of the polymer electrolyte. There is a region where the metal component is rich, and a structure in which the polymer electrolyte component becomes rich step by step (gradually) can be taken as it goes to the center of the polymer electrolyte. That is, the metal layer in the photoelectric conversion element of the present invention does not need to have a clear metal layer as a layer on the electrolyte, and at least the metals present near the outside of the polymer electrolyte are connected to each other, It is sufficient to form a portion with good electrical conductivity that can be used as Therefore, in the photoelectric conversion element of the present invention, the metal layer and the polymer electrolyte layer have a structure that does not have a clear visual interface, and a polymer electrolyte portion having a resistance value as the polymer electrolyte layer is provided. In addition, a structure (at least a pair of metal layers facing each other) sandwiched from both sides by a portion having good electrical conductivity that can contain metal as a main component and can be used as an electrode can be taken. The reason for having a polymer electrolyte portion (insulating portion) having a high resistance value as the metal layer decreases toward the center is that the plating process is carried out in water or a reducing agent solution (a polar medium in which the reducing agent is dissolved). Since the reducing agent molecule diffuses and penetrates from the outside of the polymer electrolyte to the central part, the reducing agent solution is difficult to penetrate to the central part. It is estimated that the metal itself constituting the layer cannot be completely connected. In addition, the obtained photoelectric conversion element (polymer electrolyte-metal layer composite) is cut in the vicinity of the central portion, and the polymer electrolyte (layer) is bonded in such a manner as to sandwich the cut pieces. Thus, a photoelectric conversion element having an insulating portion may be used.

  The reducing agent solution is not particularly limited as long as the reducing agent is dissolved, regardless of the shape of the polymer electrolyte. The reducing agent can be used by appropriately selecting the type according to the type of metal complex used in the metal complex solution adsorbed on the polymer electrolyte, such as sodium sulfite, hydrazine, sodium borohydride. Etc. can be used. In addition, when reducing a metal complex, you may add an acid or an alkali as needed. The concentration of the reducing agent solution is not particularly limited as long as it contains a sufficient amount of reducing agent to obtain the amount of metal to be deposited by reduction of the metal complex. It is also possible to use a concentration equivalent to that of the metal complex solution used in the case of forming a metal layer. Moreover, the solvent containing alcohol can also be used in a reducing agent solution.

  Further, in the method for producing a photoelectric conversion element of the present invention, the adsorption step and the reduction step may be performed once each, and this combination is preferably performed by performing the reduction step after the adsorption step. May be performed multiple times. By carrying out the above steps, it is dense, has a large specific surface area, can increase the amount of dye molecules adsorbed / fixed, and coupled with the SPR effect obtained when the metal layer surface is irradiated with light, photoelectric conversion A photoelectric conversion element having excellent efficiency can be obtained. In addition, when it is desired to prepare a thin metal layer, it is possible to form a thin metal layer by bringing a reducing agent solution having a low concentration into contact or by reducing the number of contacts.

<Electrolytic plating method>
The electrolytic plating method is not particularly limited, and a conventionally known method can be used. The electrolytic plating method is useful in that the film thickness of the plating can be easily adjusted by adjusting the amount of energization and the like, and is also preferable in terms of securing the film thickness. In the present invention, as a particularly preferred embodiment, a detailed electrolytic plating method will be described below.

  As a specific electrolytic plating method (electroplating method), for example, a conventionally known electrolytic plating method can be used on one side or both sides of a polymer electrolyte as in the present invention. In addition, when using a fine structure such as a polymer electrolyte as in the present invention, or when using a resin having poor electrical conductivity, a metal layer is formed in advance by an electroless plating method, Examples include a method of adjusting the film thickness of the metal layer (metal electrode) while adjusting the amount of current by an electrolytic plating method after improving the conductivity.

  Furthermore, after performing the electroless plating method, it is possible to form a metal layer (metal electrode) by applying a constant current by a constant current method, or after performing the electroless plating method, It is also possible to form a metal layer (metal electrode) by a charge / discharge method, and it can be carried out by combining these.

  Although it is possible to form a metal plating (metal layer) by the electrolytic plating method alone, more precise metal plating can be performed by using it together with the electroless plating method, which is useful. In addition, metal plating can be performed by immersing the polymer electrolyte in an electrolytic solution containing metal ions or the like and energizing it. Moreover, about the said electrolyte solution, if it can exhibit a SPR effect similarly to the electroless-plating method, a well-known electrolyte solution can be used on well-known plating conditions.

  As a plating condition in the electrolytic plating method, a conventionally known method can be used. For example, if a constant current method is adopted, the concentration of the electrolytic solution (reducing agent solution) and the reaction temperature are, for example, 20 ° C. In -60 degreeC, 1-200 mmol / l (mM) is preferable, 5-150 mM is more preferable, and 10-100 mM is especially preferable. Moreover, as reaction time, several minutes-10 hours are preferable, More preferably, they are 30 minutes-2 hours. The energization amount is preferably 0.01 mA to 10 mA, and more preferably 0.05 mA to 5 mA. Further, if the charge / discharge method is adopted, for example, 0.5 V to 3.0 V is applied for 1 to 20 seconds, 0.01 mA to 100 mA is discharged and 1 to 100 seconds is charged and discharged 10 to 1000 times. It is preferable that 1.0 to 2.5 V is applied for 3 to 10 seconds, and discharge of 0.1 mA to 30 mA is performed 30 to 300 times for 5 to 50 seconds. Within these ranges, the workability is excellent and useful.

<Metal layer>
The material of the metal layer that can be used in the photoelectric conversion element of the present invention is not particularly limited and can be manufactured using the above-described metal complex solution or the like, but in order to exert the surface plasmon resonance (SPR) effect, It is preferable to use gold, silver, copper, platinum or the like. In particular, it is more preferable to use gold having high stability even in a solvent such as water. Further, when the metal layer (metal electrode) of the photoelectric conversion element forms a pair, it may be a pair made of the same metal or a pair made of different metals (asymmetric metal layer, asymmetric metal electrode). However, it is a more preferable embodiment that the pair is made of different metals. Further, the different metal may be, for example, one of the pair being a gold layer and the other being an alloy (multiple layers) such as gold and platinum. The SPR effect can greatly improve the photoelectric conversion efficiency, and is useful as a polymer electrolyte solar cell or the like.

  Moreover, when the metal layer (metal electrode) of the photoelectric conversion element of the present invention forms a pair, as described above, it may be a pair made of the same metal, or a pair made of different metals (asymmetric metal layer). Asymmetric metal electrodes), but the metal layers forming the pairs may be manufactured by different methods. For example, one metal layer may be formed by an electroless plating method, and the other metal layer may be formed by an electroplating method. Both metal layers are once formed by an electroless plating method, and only one metal layer is formed. Further, an electrolytic plating method may be employed to increase the plating thickness (film thickness) to form a metal layer, or a metal layer made of an alloy (a metal layer composed of a plurality of different metals: a composite metal layer). There is no problem as long as the desired performance can be obtained.

  When the metal layer forms a pair, the pair may be a metal layer made of the same kind of metal. However, when different metals are used, it becomes a more preferable embodiment. By using different metals (asymmetric), a potential difference is generated between the metal layers, the flow of current (photocurrent) is increased, the practicality is increased, and this is a preferred embodiment. The different metal species are, for example, a case where one is a gold layer (gold plated layer) and the other is silver or platinum, or one is a gold layer and the other is an alloy in which platinum or the like is further plated on the gold layer ( A composite metal layer).

<Washing process>
In the case where the electroless plating method is used and the adsorption step and the reduction step are repeated, the reducing agent is removed from the polymer electrolyte to facilitate the adsorption of the metal complex in the adsorption step. Therefore, it is preferable to perform a cleaning process after the reduction process and perform an adsorption process after the cleaning process. The washing step is not particularly limited, and the reducing agent may be removed by washing with water.

  In addition, after the swelling step is performed, the photoelectric conversion element in which a metal layer (metal electrode) is formed by a plating method has a cross section of the metal layer at a magnification of 800 times at the interface between the polymer electrolyte and the metal layer. Fractal, peninsular, island, icicle, polyp, and neck shape with narrow neck, tree shape, cocoon shape, cotton (observable by scanning electron microscope (SEM) photograph (Figure 1) Even in SEM photographs with a magnification of 5000 to 10000 times, such as cotton, fibers), strips, and irregular shapes (the average particle diameter of the metal particles exceeds about 1 μm, up to about 100 μm) The average particle size of metal fine structures (metal microstructures) of 1 μm or less is the low density of metal microstructures that cannot be observed, such as cocoon, cloud, cocoon, mist, and cotton (cotton). ) It is possible. Since the shape forms a complex and dense structure (including nanostructures), the metal layer has a very large specific surface area (such as a nanostructured metal electrode). In particular, unlike a metal layer formed by sputtering or the like on a transparent conductive substrate (ITO or the like), the specific surface area is greatly increased, so that a large amount of dye molecules can be adsorbed and immobilized on the metal layer. When the surface of the metal layer is irradiated with light, not only the dye sensitization effect based on the dye molecule but also the surface plasmon resonance (SPR) effect based on the metal layer and the light irradiation is exhibited, and the usable photoelectric conversion efficiency can be improved. It is possible to plan. The surface resistance of the metal layer is preferably at the same level as the transparent conductive substrate (ITO or the like).

(Iii) Dye molecule adsorption step The photoelectric conversion element of the present invention includes a polymer electrolyte, a metal layer, and a dye molecule, and the metal layer (nanostructured metal electrode or the like) is in contact with the polymer electrolyte. The metal layer is formed on the surface and / or inside of the polymer electrolyte, and the dye molecules are adsorbed on the metal layer. Here, the dye molecule can be used without particular limitation as long as it is adsorbed on the metal layer. Examples of the adsorption include physical adsorption, electrostatic adsorption, and chemical adsorption, and it is preferable that the amount of adsorption / fixation of the dye molecules to the metal layer is large, that is, the dye molecules can be easily desorbed after adsorption. First, it is preferable to use a dye molecule having high dye sensitization efficiency. Examples of the dye molecule include black dye, ruthenium complex having bipyridine-carboxylic acid group, ruthenium complex having bipyridine group, ruthenium complex having phenanthroline group, ruthenium complex having quinoline group, β-diketonate complex, and osmium as a central metal. Complex with iron as the central metal, complex with copper as the central metal, complex with platinum as the central metal, disulfide porphyrin dye, sulfide ruthenium complex, cationic porphyrin dye having pyridinium group, bipyridinium group Cationic dye, tetrapyridinium salt dye (Chemical Formula 1), methine dye, cyanine dye, merocyanine dye, mercurochrome dye, xanthene dye, porphyrin dye, phthalocyanine dye, azo dye, Phosphorus-based dyes, and the like.

  In particular, when the metal constituting the metal layer uses gold or the like capable of exhibiting a surface plasmon resonance (SPR) effect, a sulfur compound having a property of self-adsorption (self-organization) to the gold or the like is used. This is a more preferred embodiment. The sulfur compound is self-adsorbed (self-organized) on the surface of the metal layer, thereby forming a dense monomolecular film (monomolecular layer) on the surface of the metal layer, thereby irradiating the surface of the metal layer with light. In this case, the dye sensitization efficiency can be improved, and in addition to the SPR effect, a photoelectric conversion element having a higher photoelectric conversion efficiency can be obtained.

  Examples of the dye molecule that is the sulfur compound include a sulfur compound having a disulfide bond, a thiol group, or the like, and a compound in which the sulfur compound has incorporated the dye molecule. Specific examples of the sulfur compound include the following chemical formulas 2 to 8.

  In order to adsorb and immobilize the dye molecules on the metal layer, it is possible to employ a method of immersing the polymer electrolyte in which the metal layer is formed in the dye-containing solution using the dye molecule-containing solution. . The solvent that dissolves the dye molecules is not particularly limited, but is preferably a solvent that dissolves the dye molecules. The concentration of the dye-containing solution varies depending on the metal constituting the metal layer and the dye molecule, but is preferably 0.01 to 0.50% by weight, more preferably 0.03 to 0.30% by weight, for example. Preferably, 0.05 to 0.15% by weight is particularly preferable. Within the above range, the dye molecules can be sufficiently adsorbed and immobilized on the surface of the metal layer.

(Iv) Swelling step after dye molecule adsorption (electrolytic solution)
The photoelectric conversion element of the present invention is preferably in a state where the polymer electrolyte (layer) and the metal layer adsorbed with the dye molecules are swollen and filled with the electrolytic solution. By setting it in a swollen (and filled) state, light is transmitted (arrives) not only to the metal layer on the surface of the polymer electrolyte but also to the internal metal layer, and the dye sensitizing effect and the SPR effect are efficiently improved. Can be useful. The dye molecule-containing solution used in the dye molecule adsorption step may serve as a swelling step together with the adsorption of the dye molecules to the metal layer. The solvent used in the electrolytic solution (or dye molecule-containing solution) is preferably a solvent that can dissolve the dye molecules and that can also swell the metal layer.

  The electrolytic solution (swelling solution) may be a non-aqueous (organic) electrolytic solution or an aqueous electrolytic solution. In addition, the polymer electrolyte may contain some solvent molecules of the electrolytic solution. In addition, when water is used as the electrolytic solution, in order to prevent deterioration due to ionization or corrosion of the metal of the metal layer in the charge / discharge process of the photoelectric conversion element, as the metal constituting the metal layer, It is preferable to use a noble metal. In particular, gold, silver, copper, platinum or the like is preferably used in order to exert a surface plasmon resonance (SPR) effect, and gold, silver or platinum is more preferable. Further, when the metal layer (metal electrode) of the photoelectric conversion element forms a pair, it may be a pair made of the same metal or a pair made of different metals (asymmetric metal layer, asymmetric metal electrode). However, it is a more preferable embodiment that the pair is made of different metals. Further, the different metal may be, for example, one of the pair being a gold layer and the other being an alloy (multiple layers) such as gold and platinum. Moreover, a non-aqueous polar liquid can also be used as a solvent. When a non-aqueous polar liquid having a high dielectric constant and decomposition voltage is used as a solvent, the potential window is widened, electrolysis is unlikely to occur, and it is electrochemically stable, resulting in high withstand voltage and energy density. Becomes larger. In addition, when a non-aqueous polar liquid is used as a solvent, a metal other than a noble metal such as gold (for example, copper) that is difficult to use as an electrode of a photoelectric conversion element when water is used as a solvent may be used as an electrode. This is also advantageous in terms of cost.

  Specific examples of the solvent contained in the non-aqueous electrolyte include propylene carbonate, N-methylpyrrolidone, dimethyl sulfoxide, acetonitrile, N, N-dimethylformamide, N-methylformamide (NMF), tetrahydrofuran (THF), Hexamethyl phosphate triamide, γ-butyrolactone, 1,2-dimethoxyethane, N-methylacetamide, sulfolane ethylene carbonate, glutaronitrile, adiponitrile, nitromethane, nitroethane, pyridine, preferably propylene carbonate, n-methylpyrrolidone, dimethyl Sulfoxide, N-methylformamide, γ-butyrolactone, more preferably non-propylene carbonate, N-methylformamide, γ-butyrolactone, 1,4-dioxolane, etc. Polar liquids can be mentioned, a particularly preferred polar liquids, N- methylformamide (NMF), and tetrahydrofuran (THF).

  As the solvent, N-methylformamide (NMF) and tetrahydrofuran (THF) may be mixed and used. For example, NMF: THF (volume ratio) is preferably 10:90 to 35:65, more preferably 15:85 to 30:70, and particularly preferably 20:80 to 25:75. If the amount of NMF is less than the above ratio, it cannot swell sufficiently. On the other hand, if the proportion of NHF is more than the above ratio, it swells too much and is formed on the surface and / or inside of the polymer electrolyte. The metal layer is detached and the metal layer cannot be obtained, which is not preferable.

  Moreover, as said electrolyte solution, not only the said electrolyte solution but the ether group containing compound of molecular weight 50-400 can be contained, for example, More preferably, molecular weight is 100-300. For example, it is preferable to contain at least one selected from the group consisting of polyethylene glycol (PEG), glycerol carbonate, diethylene glycol monoethyl ether, triethylene glycol monobutyl ether, and related compounds, and more preferably PEG Or glycerol carbonate. By including the compound such as PEG in the electrolytic solution, the ionic conductivity is improved, the electrical conductivity is improved, and the photocurrent is greatly increased, which is preferable. In particular, in the present invention, it is possible to obtain a photoelectric conversion element having higher photoelectric conversion efficiency by blending and dissolving the electron acceptor, redox couple, and electrolyte salt described below in the ether group-containing compound. It is possible and effective. Further, when the ether group-containing compound is non-volatile, it is excellent in workability and durability, for example, it is not necessary to replenish the electrolyte solution for a long time. Furthermore, PEG is useful because it can swell a polymer electrolyte (polyelectrolyte-metal layer composite) in which a metal layer is formed. In addition, as content of ether group containing compounds, such as said PEG, in an electrolyte solution, it can mix | blend to the solubility limit with respect to another solvent. In addition, the measuring method of molecular weight is based on gel permeability evaluation.

  As a swelling degree at the time of making it swell with the said electrolyte solution, 5 to 50% is preferable and 10 to 35% is more preferable. When it is within the above range, the metal layer (metal electrode) structure is easy to maintain the state at the time of forming the metal layer, and stable photoelectric conversion is possible, which is preferable.

  In the photoelectric conversion element of the present invention, the electrolytic solution contains an electron acceptor and a redox pair, and the electron acceptor and the redox pair (mediator) include quinones, alloxazines, and It contains at least one selected from the group consisting of ferrocenes. Furthermore, it is preferable to contain viologens together with the electron acceptor and the redox couple.

  The electron acceptor contains at least one of quinones having a base oxidation-reduction potential and alloxazines that can be used in the field of solar cells and the like, and viologens are preferably used. Use of the electron acceptor enables efficient charge separation and is useful. Specifically, anthraquinone, hydroquinone, (tetrachloro-p-benzoquinone) chloranil, vitamin K1 and the like can be used as quinones. Lumichrome (7,8-dimethylalloxazine), 1,4 -Dimethyl-3,10-diethylalloxazine and the like can be used, and as viologens, methyl viologen, hexyl viologen and the like can be used. In particular, alloxazines are preferable because of their high solubility in organic solvents and excellent workability.

  As the oxidation-reduction pair, ferrocenes (ferrocene derivatives) that can be used in the field of solar cells and the like are used, in particular, ferrocenyl alcohol (specifically, ferrocenylmethanol, ferrocenylethanol, etc.) It is preferable to use ferrocene aldehyde (specifically, ferrocene carbaldehyde or the like). By using the redox couple, reversible electrons can flow into and out of the internal polymer electrolyte (layer) from the external circuit via the metal electrode (metal layer) of the photoelectric conversion element (composite). Therefore, a permanent photovoltaic power can be obtained, which is useful.

  In the photoelectric conversion element of the present invention, the electrolytic solution preferably contains an electrolyte salt. By containing the electrolyte salt, the electrical conductivity becomes good, which is effective in terms of reducing internal resistance. The electrolyte salt is not particularly limited. For example, at least one alkali metal halide selected from the group consisting of sodium, lithium, cesium, and rubidium (fluoride, chloride, bromide, etc.) And sodium hydroxide, preferably sodium perchlorate, cesium chloride, cesium hydroxide, lithium chloride, lithium fluoride, and the like, and particularly preferably cesium chloride, lithium chloride, and the like.

  The electron acceptor, redox couple, and electrolyte salt contained in the electrolytic solution can be used as a mixture. The total content of the electrolyte in the electrolytic solution is preferably 0. It is 1-10.0 mol / l (M), More preferably, it is 0.2-5.0 mol / l. When it is within the above range, the function as a mediator is sufficiently exhibited, the electrical conductivity is improved, and it is useful in terms of photoelectric conversion.

  When the metal layers are formed in pairs, the photoelectric conversion element of the present invention can be used as a dye-sensitized solar cell without changing the configuration of the photoelectric conversion element. In particular, by filling the photoelectric conversion element with a non-volatile solvent (solution), a solar cell without a shield can be formed, which is useful in terms of cost and workability.

  Hereinafter, in Examples and Comparative Examples of the present invention, photoelectric conversion elements were formed by the following method. In addition, this invention is not limited by the following Example etc.

<Example 1>
(Pretreatment process and electroless plating process)
About the membrane-shaped polymer electrolyte (fluorine resin-based ion exchange resin: perfluorocarboxylic acid resin, trade name “Flemion”, manufactured by Asahi Glass Co., Ltd., ion exchange capacity: 1.44 meq / g) having a film thickness of 110 μm when dried The following steps (1) to (4) were performed.

(1) Pretreatment step: a membrane polymer electrolyte having a film thickness of 110 μm when dried (fluorine resin ion exchange resin: perfluorocarboxylic acid resin, trade name “Flemion”, manufactured by Asahi Glass Co., Ltd., ion exchange capacity 1.44 meq / g) was immersed in ethanol as a swelling solvent at 20 ° C. for 30 minutes or more. The film thickness of the membrane-like polymer electrolyte swollen is measured, and the ratio of the film thickness after swelling to the dry film thickness (degree of swelling (%)) is calculated, so that the degree of swelling is 50%. The membrane polymer electrolyte was immersed in a swelling solvent.
(2) Adsorption step: Dipping in a 1.1% by weight dichlorophenanthroline gold chloride aqueous solution for 12 hours to adsorb the dichlorophenanthroline gold complex in the polymer electrolyte (including the surface), Washing with water and removing the excess aqueous solution gave a metal complex-adsorbing polymer electrolyte.
(3) Reduction step: Next, the polymer electrolyte was immersed in water at 50 ° C. and adjusted to pH 6.0 with acetic acid, and then 10 ml of a 20 wt% aqueous sodium sulfite solution was added over 5 hours. Then, the adsorbed dichlorophenanthroline gold complex was reduced to form a nanostructure (fractal structure) gold electrode on the surface and inside of the membrane polymer electrolyte. At this time, the temperature of the aqueous solution was set to 60 to 80 ° C., and the dichlorophenanthroline gold complex was reduced for 6 hours while adding sodium sulfite stepwise.
(4) Washing step: The membrane-shaped polymer electrolyte having a gold electrode formed on the surface was taken out and washed with water at 70 ° C. for 1 hour to obtain a polymer electrolyte-metal layer composite. In this case, the ionic species contained in the polymer electrolyte is sodium ions derived from sodium sulfite. The surface resistance on which the obtained metal layer (gold electrode) was formed was a polymer electrolyte-metal layer composite of several Ω / cm.

(Asymmetric electrode formation process)
Subsequently, using the electroplating apparatus of FIG. 2, as an electrolytic solution (reducing agent solution), a tetravalent platinum (Pt) ammine chloride aqueous solution (containing [Pt (NH ₃ ) _n ] Cl ₄ and NH ₄ Cl, Pt The polymer electrolyte-metal layer composite produced by electroless plating was previously immersed in the electrolyte at room temperature for 1 hour or more at a concentration of 0.9 to 2.0 wt%, manufactured by Tanaka Kikinzoku, and then galvanostat ( HA-501 (manufactured by Hokuto Denko) was set so that a constant current of 10 mA flows (constant current method), and when energized for 4 hours, a thin film was formed on the cathode side surface of the polymer electrolyte-metal layer composite. A polymer electrolyte-metal layer composite obtained by electrodepositing Pt on one side colored grayish white was obtained. The obtained polymer electrolyte-metal layer composite was washed with water at 50 ° C. for 1 hour and then air-dried to obtain an asymmetric electrode for a solar cell.

(Dye molecule adsorption process)
The complex was dissolved in 0.5 mmol / l (0.5 mM) of a solution (adsorption solution, NMF: THF = 20: 80 (volume ratio)) containing a disulfide-type porphyrin dye molecule having the structure shown in Chemical Formula 2 above. Immerse at 1 ° C for 1 hour to adsorb the dye molecules on the surface of the metal layer (metal electrode) (self-adsorption), then return to room temperature and immerse in THF to remove excess dye molecules that have not been adsorbed Removed. A composite with a swelling degree of 30% was obtained with THF.

(Manufacturing process of photoelectric conversion element)
The swollen complex is a metal that does not elute dye molecules and is strongly adsorbed (adhered) to the surface of the metal layer (gold electrode) of the metal microstructure (nanostructure) in which the dye molecules form gold fine particles, fractal structures, etc. A polymer electrolyte-metal layer-dye molecule complex in which the layers formed a pair, that is, a photoelectric conversion element A could be obtained. The photoelectric conversion element A is shown in FIG. 1 (SEM photograph: magnification 800 times). In the SEM photography, the photoelectric conversion element A is cut in a direction perpendicular to the thickness direction, a cross section is cut out, and the cut cross section is subjected to a predetermined process for SEM observation, and then the cross section is cut. Was observed by SEM photographs.

  The photoelectric conversion element A is immersed in an electrolytic solution having the composition shown in Table 1 (including the annotation composition under Table 1) at 50 ° C. for 1 hour, and then air-dried at room temperature for 6 hours. Lead wires were installed on both surfaces of the metal layer of A, and used as samples for evaluation. Subsequently, irradiation with white light from one metal layer side of the sample (Xe Hypermonolite HM-250Q type, 380 to 1200 nm, manufactured by JASCO Corporation) is performed, and a current induced between the two metal layers, so-called Photocurrent (manufactured by Fuso, measured by Potentiostat Huso HECS) was measured. The results are shown in Table 1. In the present invention, light irradiation was performed at a certain distance from a light source to a sample (electrochemical cell or the like).

<Example 2>
Using the electroplating apparatus of FIG. 3, a tetravalent platinum ammine chloride aqueous solution (containing [Pt (NH ₃ ) _n ] Cl ₄ and NH ₄ Cl, Pt concentration: 0.9 to 2 as an electrolytic solution (reducing agent solution)) In the same manner as in Example 1, a polymer electrolyte-metal layer composite produced by electroless plating was previously immersed in the electrolytic solution for 1 hour or more at room temperature, and then a charge / discharge device. (HJ201B, manufactured by Hokuto Denko Co., Ltd.) The gold electrode (mesh electrode) was sandwiched, and 2.5V × 11 second application and 3 mA discharge 3 second charge / discharge operation were repeated 200 times. Thus, a polymer electrolyte-metal layer composite obtained by electrodepositing platinum (Pt) on one side that was lightly grayish white was obtained. The obtained polymer electrolyte-metal layer composite was washed with 50 ° C. water for 1 hour and then air-dried to be used as an asymmetric electrode for a solar cell.

  The dye molecule adsorption process and the photoelectric conversion element manufacturing process are the same as in Example 1, and the composition of the electrolyte contained in the photoelectric conversion element is adjusted to the contents shown in Table 1 and evaluated. It was.

<Example 3>
Using the electroplating apparatus of Example 2, a polymer having a thickness of 55 μm at the time of drying produced by electroless plating in a 0.25M silver nitrate aqueous solution as an electrolytic solution (reducing agent solution) as in Example 1 1. An electrolyte-metal layer composite is preliminarily immersed in the electrolyte solution at room temperature for 0.5 hour, and then a gold electrode (mesh electrode) is sandwiched between them using a charge / discharge device (HJ201B, manufactured by Hokuto Denko). A polymer electrolyte in which silver (Ag) was electrodeposited on one surface colored silver on the cathode side surface after 5 V × 41 seconds application and 10 mA discharge for 3 seconds charge / discharge operation (charge / discharge method) was repeated 100 times. -A metal layer composite was obtained. At this time, 10 mA discharge at the first charge and discharge in several seconds (to reach potential 0V), but at the last charge, the discharge time of about 1 minute was maintained under the same conditions. It was confirmed that Ag ions in the liquid were deposited on the gold electrode surface of the cathode.

  The dye molecule adsorption process and the photoelectric conversion element manufacturing process are the same as in Example 1, and the composition of the electrolyte contained in the photoelectric conversion element is adjusted to the contents shown in Table 1 and evaluated. It was.

<Example 4>
One side of a 50 μm thick Flemion film (1.44 meq, manufactured by Asahi Glass Co., Ltd.) was thermally deformed at 50 ° C. and placed on a smooth plate (glass, plastic, etc.) of a material that does not corrode at a pH of 5-6. The sides were fixed with plating tape so as not to become wrinkles, and the entire surface of one side was covered so as not to come into contact with the liquid (masking). When the reduction reaction (reduction step) described in Example 1 is performed in this masking state, a gold electrode is formed on the surface that is in contact with (immersed in) the plating bath. As long as there was no liquid leakage, no gold electrode was formed. Here, various conditions such as reaction time and reaction temperature were performed under the same conditions as those for forming the gold electrode (counter electrode) manufactured in Example 1, and a polymer in which a gold electrode was formed (gold plated) only on one side surface. An electrolyte-metal layer composite was obtained.

The polymer electrolyte-metal layer composite that is gold-plated (gold electrode formation) only on one surface is washed at 50 ° C. for 30 minutes, and further 10 mM silver nitrate (AgNO ₃ ) aqueous solution to which 5% NH ₃ water is added is used as a reducing agent. As the (solution), this time the formed gold electrode (gold layer) side is masked and immersed in water, and the reducing agent solution is adjusted to 40 ° C. on the unreacted (unplated) surface. And left for 1 hour. At this time, a polymer electrolyte-metal layer composite having a surface resistance of 10 to 20 Ω / cm at the first reduction and a surface resistance of 5 to 10 Ω / cm at the second reduction is obtained, and inside the polymer electrolyte-metal layer composite, It was confirmed that a silver electrode having a fractal structure similar to that of gold was formed.

  The dye molecule adsorption process and the photoelectric conversion element manufacturing process are the same as in Example 1, and the composition of the electrolyte contained in the photoelectric conversion element is adjusted to the contents shown in Table 1 and evaluated. It was.

<Example 5>
As an electrolytic solution (reducing agent solution), a tetravalent platinum ammine chloride aqueous solution (containing [Pt (NH ₃ ) _n ] Cl ₄ and NH ₄ Cl, Pt concentration: 0.9 to 2.0 wt%, manufactured by Tanaka Kikinzoku) A polymer electrolyte-metal layer composite having a silver electrode on one side surface was obtained in the same manner as in Example 4 except that it was immersed (contacted) at room temperature for 20 hours and subjected to a reduction reaction. Next, when the reduction was repeated four times while maintaining the solution temperature of the reducing agent at 60 ° C. for 60 minutes, the surface resistance gradually decreased and a Pt film (platinum electrode) of several Ω / cm was formed. . At this time, formation of a fractal structure was not recognized in the inside of the polymer electrolyte-metal layer composite as in Example 4, and it was in a lump (solid) state.

  The dye molecule adsorption process and the photoelectric conversion element manufacturing process were the same as in Example 1. The composition of the electrolyte contained in the photoelectric conversion element was prepared as shown in Table 1 and evaluated. .

<Examples 6 to 14>
About Examples 6-14, each photoelectric conversion element was prepared by the method similar to Example 2 except having used what shows the composition of the electrolyte solution contained in a photoelectric conversion element in Table 1.

<Comparative Example 1>
A photoelectric conversion element was produced in the same manner as in Example 1 except that the step of forming the asymmetric electrode was not performed. Moreover, the composition of the electrolyte solution contained in the photoelectric conversion element was prepared to the contents shown in Table 1 and evaluated.

注）実施例及び比較例全てにおいて、表１に記載の組成以外に、電解液の組成（内容）としては、純水：４０ｖｏｌ％、ＰＥＧ（重量平均分子量２００のポリエチレングリコール）：６０ｖｏｌ％、及び、塩化セシウム（電解液中の濃度：１．０Ｍ)を含有した。

Note) In all the examples and comparative examples, in addition to the composition described in Table 1, the composition (contents) of the electrolytic solution is as follows: pure water: 40 vol%, PEG (polyethylene glycol having a weight average molecular weight of 200): 60 vol%, and And cesium chloride (concentration in electrolyte: 1.0 M).

Details of the composition (electron acceptor and acid reduction pair: mediator) in Table 1 are shown below.
Methyl viologen (Tokyo Chemical Industry Co., Ltd., 1,1′-dimethyl-4,4′-pyridinium dichloride hydrate)
Anthraquinone (manufactured by Tokyo Chemical Industry Co., Ltd.)
Hydroquinone (manufactured by Tokyo Chemical Industry Co., Ltd.)
(Tetrachloro-p-benzoquinone) chloranil (manufactured by Tokyo Chemical Industry Co., Ltd.)
Lumichrome (7,8-dimethylalloxazine, Sigma-Aldrich)
1,4-dimethyl-3,10-diethylalloxazine ferrocenylmethanol (manufactured by Wako Pure Chemical Industries)
Ferrocene aldehyde (manufactured by Wako Pure Chemical Industries)

  The 1,4-dimethyl-3,10-diethylalloxazine was synthesized by adding 60 g of a dimethylformamide (DMF) solution containing 1 g of lumichrome, 3.7 g of anhydrous sodium carbonate as a catalyst, and diethyl iodide 4 0.5 g was added and stirred at room temperature for 2 days. Thereafter, a large amount of water was poured into the reaction mixture to precipitate crude crystals, which were allowed to stand for half a day, and then the resulting pale yellow-green precipitate was collected by filtration. The precipitate collected by filtration was washed with a small amount of cold (10 ° C.) methanol, recrystallized from a water-ethanol mixed solvent (mixing ratio 1: 1) and dried. This crystal is easily soluble in ethanol, acetone, ethyl acetate, and toluene and has a different property from the starting material lumichrome (7,8-dimethylalloxazine). It was confirmed that it was −3,10-diethylalloxazine. Japanese Patent Publication No. 4-25532 can be referred to for the synthesis method of other alloxazines that can be used in the present invention.

<Evaluation results>
From the result of the said Example, since the photoelectric conversion element of this invention uses the metal layer which has a very large specific surface area as a metal layer, not only the dye-sensitizing effect by adsorption | suction of a dye molecule but SPR Based on the effect, it was confirmed that an excellent photoelectric conversion effect (efficiency) can be obtained. In addition, a photoelectric conversion element can be manufactured without using ITO or the like, and not only using ITO but also by a new electric field enhancement effect (for example, SPR effect). It is possible to use light in the infrared region, and an improvement in photoelectric conversion efficiency is recognized, and it is estimated that these generate further photocurrent.

  In addition, it can be confirmed that a large photocurrent can be obtained by containing a specific redox pair contained in the electrolytic solution that fills the inside of the photoelectric conversion element, and is extremely useful as a polymer electrolyte solar cell. In particular, even when compared with Comparative Example 1, it was confirmed that a clearly large photocurrent could be obtained.

  Furthermore, the metal layers forming the photoelectric conversion element are a combination of metal layers formed from different metals, so that a potential difference occurs between the metal layers, and a larger photocurrent can be generated. It was also confirmed that.

A: Photoelectric conversion element A
1: Metal layer (metal electrode)
2: Polymer electrolyte 11: Constant current power supply (galvanostat)
12: Anode 13: Cathode 14: Platinum (Pt) electrode 15: Gold electrode 15 ′: Gold electrode 16: Plating bath 17: Charge / discharge device 20: Platinum electrodeposition device 30: Platinum electrodeposition device

Claims (13)

A photoelectric conversion element comprising a polymer electrolyte, a metal layer, and a dye molecule,
The photoelectric conversion element contains at least one selected from the group consisting of quinones, alloxazines, and ferrocenes,
The metal layer is in contact with the polymer electrolyte, and the metal layer is formed on the surface and / or inside of the polymer electrolyte,
The photoelectric conversion element, wherein the dye molecule is adsorbed on the metal layer.   Furthermore, viologens are contained, The photoelectric conversion element of Claim 1 characterized by the above-mentioned.   The photoelectric conversion element according to claim 1, wherein the dye molecule is a sulfur-containing compound.   The photoelectric conversion element according to claim 1, wherein the polymer electrolyte is an ion exchange resin.   5. The photoelectric conversion element according to claim 1, comprising an electrolyte salt.   The photoelectric conversion element according to claim 1, comprising an ether group-containing compound having a molecular weight of 50 to 400.   The photoelectric conversion element according to claim 1, wherein the metal layer forms a pair.   The photoelectric conversion element according to claim 7, wherein one metal layer forming the pair and the other metal layer are formed of different metals. The photoelectric conversion element according to claim 7 or 8,
Toward the outside of the polymer electrolyte, the metal microstructure constituting the metal layer has a rich region,
The photoelectric conversion element, wherein the polymer electrolyte has a rich region toward the center of the polymer electrolyte.   A polymer electrolyte solar cell comprising the photoelectric conversion element according to claim 1. It is a manufacturing method of the photoelectric conversion element in any one of Claims 1-9,
Forming the metal layer on the surface and / or inside of the polymer electrolyte by an electroplating method and / or an electroless plating method;
Adsorbing dye molecules to the metal layer;
And a step of swelling the polymer electrolyte and the metal layer adsorbed with the dye molecules with a solvent or a solution. The metal layers form a pair;
The method for producing a photoelectric conversion element according to claim 11, wherein one metal layer forming the pair and the other metal layer are formed by different methods.   The electroless plating method includes an adsorption step in which a metal complex is adsorbed on the polymer electrolyte, and a reduction step in which a reducing agent solution is brought into contact with the polymer electrolyte on which the metal complex is adsorbed to form a metal layer. The method for producing a photoelectric conversion element according to claim 11 or 12.

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