JP2012243436A - Photoelectric conversion element, method for manufacturing the same, and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoelectric conversion element allowing an electrolytic solution constituting an electrolyte layer to be colorless and transparent, or to be sufficient thin color without impairing photoelectric conversion characteristics too much, and a method for manufacturing the same.SOLUTION: A photoelectric conversion element comprises an electrolyte layer 7 composed of an iodine redox-based electrolytic solution which contains an additive composed of a compound exhibiting a stronger interaction with iodine molecules than with iodide ions between a porous electrode 3 and a counter electrode 6. The additive composed of a compound exhibiting a stronger interaction with iodine molecules than with iodide ions is preferably a nonionic additive whose conjugate acid has a pK(HO) of 9.12 or higher and/or an ionic additive whose conjugate acid of an anion has a pK(HO) of 4.76 or higher. In one embodiment, the nonionic additive is at least one member selected from the group consisting of heterocyclic compounds, cyclic amines, linear amines, diamines, amidines, guanidine, and phosphazenes.

Description

  The present disclosure relates to a photoelectric conversion element, a manufacturing method thereof, and an electronic device, for example, a photoelectric conversion element suitable for use in a dye-sensitized solar cell, a manufacturing method thereof, and various electronic devices using the photoelectric conversion element. .

  Solar cells, which are photoelectric conversion elements that convert sunlight into electrical energy, use sunlight as an energy source, and therefore have very little influence on the global environment, and are expected to become more widespread.

  Conventionally, crystalline silicon solar cells using single crystal or polycrystalline silicon and amorphous silicon solar cells are mainly used as solar cells.

  On the other hand, the dye-sensitized solar cell proposed by Gretzell et al. In 1991 can obtain high photoelectric conversion efficiency, and unlike a conventional silicon-based solar cell, it does not require a large-scale device for production, and has a low It is attracting attention because it can be manufactured at low cost (for example, see Non-Patent Document 1).

  This dye-sensitized solar cell generally has a porous electrode made of titanium oxide or the like on which a dye for photosensitization is adsorbed and a counter electrode made of platinum or the like facing each other, and an electrolyte made of an electrolytic solution between them. It has a structure filled with layers. As the electrolytic solution, an iodine redox electrolytic solution in which an electrolyte containing iodine as an oxidizing / reducing species is dissolved in a solvent is used (for example, see Patent Document 1). In the dye-sensitized solar cell, the highest photoelectric conversion characteristic is obtained using this iodine redox electrolyte.

  On the other hand, when the dye-sensitized solar cell is installed on the outer wall of a building, the interior interior, a mobile device, or the like, the dye-sensitized solar cell itself needs to be designed. In order to obtain the highest photoelectric conversion characteristics in a dye-sensitized solar cell, it is currently necessary to use an iodine redox electrolyte, but because there is light absorption in the visible light region derived from the redox couple, The electrolyte is colored brownish. This is an obstacle to imparting design to the dye-sensitized solar cell. In order to impart designability, the dye-sensitized solar cell, and thus the electrolyte, may be desired to be colorless and transparent, or may be sufficiently weakly colored even if it is colored brown.

  Regarding the coloring of this iodine redox electrolyte solution, it has been proposed to lighten the color by greatly reducing the iodine composition in the electrolyte solution (see Patent Document 2).

Japanese Patent Laid-Open No. 2006-146331 JP 2005-251736 A US Pat. No. 6,310,282 JP 2007-149675 A

Nature, 353, p.737-740,1991 Journal of Physical Chemistry B 2008,112, 13775-13781 Inorg.Chem.1996,35,1168-1178 J. Chem. Phys. 124, 184902 (2006)

  However, in the method of Patent Document 2, it is difficult to make colorless and transparent even though it is possible to lighten the color of the iodine redox electrolyte by reducing the iodine composition. In addition, since the composition range described in Patent Document 2 is narrow and there is little room for composition selection, high photoelectric conversion characteristics cannot be obtained.

  Therefore, the problem to be solved by the present disclosure is to provide a photoelectric conversion element capable of making the electrolyte solution constituting the electrolyte layer colorless and transparent or sufficiently weakly colored without significantly reducing the photoelectric conversion characteristics, and a method for manufacturing the photoelectric conversion element It is to be.

  Another problem to be solved by the present disclosure is to provide a high-performance electronic device using the excellent photoelectric conversion element as described above.

  The above and other problems will become apparent from the description of this specification with reference to the accompanying drawings.

In order to solve the above problems, the present disclosure provides:
It is a photoelectric conversion element which has the electrolyte layer which consists of an iodine redox type | system | group electrolyte solution containing the additive which consists of a compound which shows a strong interaction with an iodine molecule rather than an iodide ion between a porous electrode and a counter electrode.

In addition, this disclosure
Manufacture of a photoelectric conversion element having a step of forming an electrolyte layer provided between a porous electrode and a counter electrode with an iodine redox electrolyte containing an additive composed of a compound having a stronger interaction with iodine molecules than iodide ions Is the method.

In addition, this disclosure
Having at least one photoelectric conversion element;
The photoelectric conversion element is
It is an electronic device that is a photoelectric conversion element having an electrolyte layer made of an iodine redox electrolyte solution containing an additive made of a compound that has a stronger interaction with iodine molecules than iodide ions between a porous electrode and a counter electrode .

In the present disclosure, Lewis basicity can be referred to as an indicator of the range of compounds that exhibit stronger interaction with iodine molecules (I ₂ ) than iodide ions (I ⁻ ). The additive composed of a compound having a stronger interaction with iodine molecules than iodide ions is preferably _a nonionic additive and / or an anion having _a conjugate acid pKa (H ₂ O) of 9.12 or more. It is an ionic additive having a pKa (H ₂ O) of _a conjugate acid of 4.76 or more. Here, K _a (H ₂ O) is an equilibrium constant of dissociation equilibrium of the conjugate acid in water. The nonionic additive is, for example, at least one selected from the group consisting of heterocyclic compounds, cyclic amines, chain amines, diamines, amidines, guanidines and phosphazenes. Specifically, the nonionic additive is, for example, at least one selected from the group consisting of 4-N, N-dimethylaminopyridine, 4-pyrrolidinopyridine, quinuclidine, and 4-amino-pyridine. The ionic additive is, for example, a compound containing at least one selected from the group consisting of a carboxy anion, an alkoxy anion, a mercapto anion, a carbon anion, and an amide anion. The cation of this compound may be basically any as long as it is chemically stable. Specifically, the ionic additive is, for example, 1-ethyl-3-methylimidazolium acetate and / or 1-ethyl-3-methylimidazolium decanonate.

The photoelectric conversion element is typically a dye-sensitized photoelectric conversion element in which a photosensitizing dye is adsorbed on a porous electrode. In this case, the method for producing a photoelectric conversion element includes a step of adsorbing a photosensitizing dye to the porous electrode. This porous electrode is composed of fine particles made of a semiconductor. The semiconductor preferably comprises titanium oxide (TiO ₂ ), especially anatase TiO ₂ .

As the porous electrode, one composed of fine particles having a so-called core-shell structure may be used. In this case, the photosensitizing dye may not necessarily be adsorbed. As the porous electrode, preferably used is one constituted by fine particles comprising a core made of metal and a shell made of a metal oxide surrounding the core. When such a porous electrode is used, when an electrolyte layer made of an electrolytic solution is provided between the porous electrode and the counter electrode, the electrolyte of the electrolytic solution is in contact with a metal / metal oxide fine metal core. Therefore, dissolution of the porous electrode by the electrolyte can be prevented. For this reason, gold (Au), silver (Ag), copper (Cu), or the like, which has been difficult to use in the past and has a large surface plasmon resonance effect, is used as the metal constituting the metal / metal oxide fine particle core. Thus, the effect of surface plasmon resonance can be sufficiently obtained in photoelectric conversion. In addition, an iodine-based electrolyte can be used as the electrolyte of the electrolytic solution. Platinum (Pt), palladium (Pd), etc. can also be used as the metal constituting the core of the metal / metal oxide fine particles. As the metal oxide constituting the shell of the metal / metal oxide fine particles, a metal oxide that does not dissolve in the electrolyte to be used is used, and is selected as necessary. Such a metal oxide is preferably at least one selected from the group consisting of titanium oxide (TiO ₂ ), tin oxide (SnO ₂ ), niobium oxide (Nb ₂ O ₅ ), and zinc oxide (ZnO). However, the present invention is not limited to these. For example, a metal oxide such as tungsten oxide (WO ₃ ) or strontium titanate (SrTiO ₃ ) can be used. The particle diameter of the fine particles is appropriately selected, but is preferably 1 to 500 nm. The particle diameter of the core of the fine particles is also appropriately selected, but is preferably 1 to 200 nm.

  The photoelectric conversion element is most typically configured as a solar cell. However, the photoelectric conversion element may be other than a solar cell, for example, an optical sensor.

  By the way, in the conventional method for producing a dye-sensitized solar cell, the method of immersing the porous electrode in a photosensitizing dye solution is most commonly used to adsorb the photosensitizing dye to the porous electrode. ing. However, since this method requires a large amount of photosensitizing dye solution, the photosensitizing dye is expensive and the production cost increases. In addition, while the porous electrode is repeatedly immersed in the photosensitizing dye solution, the photosensitizing dye solution may be contaminated or the composition of the photosensitizing dye solution may be changed. As a result, the porous electrode is contaminated. Or the amount of adsorption of the photosensitizing dye may vary from porous electrode to porous electrode. On the other hand, the step of adsorbing the photosensitizing dye to the porous electrode by covering the surface of the porous electrode that does not adsorb the dye with a mask and contacting with the photosensitizing dye solution is repeated while changing the type of the photosensitizing dye. Thus, a method for manufacturing a dye-sensitized solar cell exhibiting a multicolor appearance has been proposed (see, for example, Patent Document 3). However, in the multicolor dye-sensitized solar cell of Patent Document 3, it is necessary to repeat the complicated process of covering the surface of the porous electrode that does not adsorb the photosensitizing dye with a mask and bringing it into contact with the photosensitizing dye solution. Therefore, there is a problem that the manufacturing process is complicated. In addition, as pointed out in Patent Document 4, this method has a problem that the image quality is low and contrast control does not remain due to bleeding of the photosensitizing dye (see paragraph 0020). These problems can be solved by the following method. That is, when manufacturing a photoelectric conversion element having an electrolyte layer between a porous electrode and a counter electrode, at least one of the steps of treating the porous electrode with a liquid or depositing the liquid on the porous electrode. The holding material holding the liquid is pressed against the porous electrode, and the liquid is supplied from the holding material to the porous electrode. This makes it possible to form a multicolored region with clear boundaries without complicating the manufacturing process and preventing bleeding of the photosensitizing dye, and providing high-quality and easy contrast control. Photoelectric conversion elements such as sensitized solar cells can be manufactured. The holding material for holding the liquid is not particularly limited as long as it has an appropriate holding ability of the liquid, and is appropriately selected according to the liquid to be held. Specific examples of the holding material include non-woven fabrics, paper, sponges, pastes, and gels of various materials, but are not limited thereto.

  The step of treating the porous electrode with the liquid or attaching the liquid onto the porous electrode is specifically, for example, a step of treating the porous electrode with a photosensitizing dye solution, or treating the porous electrode with a treatment liquid. Or it is at least one of the process of processing with a washing | cleaning liquid, the process of immersing electrolyte solution in a porous electrode, and the process of making electrolyte solution adhere on a porous electrode. The step of treating the porous electrode with the photosensitizing dye solution is a step of adsorbing the photosensitizing dye to the porous electrode. The step of treating the porous electrode with the treatment liquid or the washing liquid may be performed by, for example, treating the porous electrode with the treatment liquid in order to make the photosensitizing dye easily adsorbed on the porous electrode, or cleaning the surface of the porous electrode with a washing liquid such as water or alcohol. It is the process of washing. The step of immersing the electrolytic solution in the porous electrode is a step for spreading the electrolytic solution in the voids of the porous electrode before the electrolytic solution injection step. The step of attaching the electrolytic solution onto the porous electrode is a step of dropping the electrolytic solution onto the porous electrode, for example, like a liquid crystal drop injection (ODF) step.

  Even if the step of treating the porous electrode with the photosensitizing dye solution is a step of treating the entire porous electrode with one type of photosensitizing dye solution, the porous electrode can be treated with a plurality of types of photosensitizing dye solutions. May be a step of partially processing each of the above. In the latter case, a plurality of holding materials for holding different photosensitizing dye solutions in which different photosensitizing dyes are dissolved are used, and these holding materials are pressed against different portions of the porous electrode. This step is carried out by supplying the photosensitizing dye solution from the holding material to the porous electrode.

  When the porous electrode is formed on the transparent conductive substrate, at least one of the steps of treating the surface of the transparent conductive substrate with the liquid before forming the porous electrode on the transparent conductive substrate, You may make it perform by pressing the holding material to hold | maintain to a transparent conductive substrate, and supplying a liquid from a holding material to a transparent conductive substrate. The transparent conductive substrate has a transparent electrode (or a transparent conductive layer) provided on one main surface of the transparent substrate.

  By the way, the conventional dye-sensitized solar cell is generally manufactured by the following method. First, a porous electrode is formed on a transparent conductive substrate. Next, a counter electrode is prepared, and the porous electrode and the counter electrode on the transparent conductive substrate are arranged so as to face each other. And the sealing material is formed in the outer peripheral part of a transparent conductive substrate and a counter electrode, and the space where an electrolyte layer is enclosed is made. Next, an electrolytic solution is injected from a liquid injection hole formed in advance on the counter electrode to form an electrolyte layer. Next, the electrolytic solution that protrudes outward from the liquid injection hole of the counter electrode is wiped off. Thereafter, a sealing plate is attached on the counter electrode so as to close the liquid injection hole. As described above, the target dye-sensitized solar cell is manufactured. However, in this conventional dye-sensitized solar cell, when the dye-sensitized solar cell is damaged for some reason, an electrolyte solution is externally provided from the electrolyte layer sealed between the porous electrode and the counter electrode. There was a risk of leakage. As a result of intensive studies to solve this problem, the present inventors have found that a dye-sensitized solar cell, more generally a photoelectric conversion element, is a porous material containing an electrolytic solution between a porous electrode and a counter electrode. It has been found that it is effective to provide a structure provided with an electrolyte layer made of a porous membrane. Such a method for producing a photoelectric conversion element includes, for example, a step of installing a porous film on one of a porous electrode and a counter electrode, and a step of placing the porous electrode and the counter electrode on the porous film. And installing the other. In this method for manufacturing a photoelectric conversion element, the porous film at the time of installation on one of the porous electrode and the counter electrode may or may not contain an electrolytic solution. When a porous film containing an electrolytic solution is used, the porous film containing the electrolytic solution constitutes an electrolyte layer. In the case of using a porous membrane that does not contain an electrolytic solution, the electrolytic solution can be injected into the porous membrane in a later step. For example, the electrolytic solution can be injected into the porous film with the porous film sandwiched between the porous electrode and the counter electrode. Typically, after setting a porous film on a porous electrode, a counter electrode is set on the porous film, but the present invention is not limited to this. This photoelectric conversion element manufacturing method compresses the porous film, if necessary, after installing a porous film containing an electrolytic solution on the porous electrode and before installing a counter electrode on the porous film. Typically, the method further includes a step of compressing the porous membrane by pressing it from a direction perpendicular to the membrane surface. By doing so, when the volume of the porous membrane is reduced due to compression, the electrolytic solution contained in the void portion of the porous membrane is pushed out and penetrates into the porous electrode. For this reason, it is possible to easily realize a state in which the electrolytic solution has spread from the porous film to the porous electrode. Various types of porous membranes can be used as the electrolyte layer, and the structure and material are selected as necessary. As this porous film, an insulating material is used. Even if this insulating porous film is made of an insulating material, for example, the surface of the void portion of the porous film made of a conductive material is used. May be formed into an insulator, or the surface of the gap may be coated with an insulating film. This porous film may be made of an organic material or an inorganic material. As this porous film, various non-woven fabrics are preferably used, and as the material, for example, various organic polymer compounds such as polyolefin, polyester, cellulose and the like can be used, but are not limited thereto. Absent. The porosity of the porous film is selected as necessary, but the porosity (actual porosity) in the state provided between the porous electrode and the counter electrode is preferably 50% or more. This actual porosity is preferably selected from 80% to less than 100% from the viewpoint of obtaining high photoelectric conversion efficiency. From the viewpoint of preventing volatilization, the electrolyte contained in the porous membrane constituting the electrolyte layer is preferably a low-volatile electrolyte, for example, an ionic liquid electrolyte using an ionic liquid as a solvent. It is done. A conventionally well-known thing can be used as an ionic liquid, and it selects as needed.

By the way, guanidinium thiocyanate (GuSCN) is known as an additive for an electrolytic solution that improves the initial photoelectric conversion efficiency of a dye-sensitized solar cell (see Non-Patent Document 2). However, according to the study by the present inventors, the dye-sensitized solar cell in which GuSCN is added to the electrolytic solution has a problem that the durability is greatly reduced as a result of performing an endurance test at 85 ° C. in a dark place. I understood. In order to solve this problem and to improve the durability of the dye-sensitized solar cell, the present inventors include GuOTf (guanidinium trifluorosulfonate), EMImSCN (1- 1-ethyl-3-methylimidazolium thiocyanate, EMImOTf (1-ethyl-3-methylimidazolium trifluorosulfonate), EMImTFSI (1- 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide), EMImTfAc (1-ethyl-3-methylimidazolium trifluoroacetate (1-ethyl-3 -methylimidazolium trifluoroacetate)), EMImDINHOP (1-ethyl- - methylimidazolium di neo-hexyl phosphinate (1-ethyl-3-methylimidazolium dineohexylphosphinate)), EMImMeSO 3 (1- ethyl-3-methylimidazolium methylsulfonate (1-ethyl-3-methylimidazolium methylsulfonate)), EMImDCA (1 1-ethyl-3-methylimidazolium dicyanoamide, EMImBF ₄ (1-ethyl-3-methylimidazolium tetrafluoroborate), EMImPF ₆ (1-ethyl-3-methylimidazolium hexafluorophosphate), EMImFAP (1-ethyl-3-methylimidazolium tris (pentafluoroethyl) trifluorophosphate (1-ethyl) -3-methylimidazolium tris (pentafluoroethy l) trifluorophosphate)), EMImEt ₂ PO ₄ (1-ethyl-3-methylimidazolium diethylphosphate) and EMImCB ₁₁ H ₁₂ (1-ethyl-3-methylimidazolium 1- It has been found that it is effective to add at least one additive selected from the group consisting of carb-closo-dodecaborate (1-ethyl-3-methylimidazolium 1-carba-closo-dodecaborate). The chemical structure of the cation and the anion constituting this additive (second additive) is as follows.

・［ＥＭＩｍ］

(1) Cation [Gu]

・ [EMIm]

・ＳＣＮ

・［ＴＦＳＩ］

・［ＴｆＡｃ］

・［ＤＩＮＨＯＰ］

・［ＭｅＳＯ₃ ］

・［ＤＣＡ］

・ＢＦ₄

・ＰＦ₆

・［ＦＡＰ］

・［Ｅｔ₂ ＰＯ₄ ］

・ＣＢ₁₁Ｈ₁₂

(2) Anion / [OTf]

・ SCN

・ [TFSI]

[TfAc]

・ [DINHOP]

・ [MeSO ₃ ]

・ [DCA]

・ BF ₄

・ PF ₆

・ [FAP]

・ [Et ₂ PO ₄ ]

・ CB ₁₁ H ₁₂

By the way, the electrolyte layer is typically made of an electrolytic solution, and it is common to add an additive to the electrolytic solution in order to prevent reverse electron transfer from the porous electrode to the electrolytic solution. As this additive, 4-tert-butylpyridine (TBP) is best known, but the types of additives in the electrolyte are limited, and the range of choice of additives is extremely narrow. The degree of freedom of design was low. Therefore, the present inventors have conducted empirical studies theoretically and theoretically in order to broaden the range of selection of the above additives. As a result, it has been found that there are many additives that can obtain characteristics superior to 4-tert-butylpyridine, which has been conventionally used, as additives to be added to the electrolytic solution. Specifically, pK _a (H ₂ O) is 6.04 or more 7.03 or less, that is, if the additive of _{6.04 ≦ pK a (H 2 O} ) ≦ 7.3, 4-tert- butyl The conclusion has been reached that properties superior to pyridine can be obtained. For this purpose, 6.04 ≦ pK _a in the electrolyte (H ₂ O) ≦ 7.3 additive (third additive) is added, and / or at least one of the porous electrodes and a counter electrode the surface facing the one of the electrolyte layer, adsorbing the third additive _{6.04 ≦ pK a (H 2 O} ) ≦ 7.3. Thereby, the photoelectric conversion element which can obtain the characteristic more excellent than the case where the range of selection of the additive of electrolyte solution is large and 4-tert-butylpyridine is used as an additive can be obtained.

Was added to the electrolytic solution, or a third additive that is adsorbed to the porous electrode and at least one surface of the counter _{electrode, 6.04 ≦ pK a (H 2} O) as long as ≦ 7.3, the basic Any type may be used. The third additive is typically a pyridine-based additive or an additive having a heterocyclic ring. Specific examples of the pyridine-based additive include 2-aminopyridine (2-NH2-Py), 4-methoxypyridine (4-MeO-Py), 4-ethylpyridine (4-Et-Py), and the like. However, the present invention is not limited to this. Specific examples of the additive having a heterocyclic ring include N-methylimidazole (MIm), 2,4-lutidine (24-Lu), 2,5-lutidine (25-Lu), and 2,6-lutidine. (26-Lu), 3,4-lutidine (34-Lu), 3,5-lutidine (35-Lu) and the like, but are not limited thereto. Examples of the additive include 2-aminopyridine, 4-methoxypyridine, 4-ethylpyridine, N-methylimidazole, 2,4-lutidine, 2,5-lutidine, 2,6-lutidine, 3,4- It consists of at least one selected from the group consisting of lutidine and 3,5-lutidine. A compound having a structure of pyridines or heterocyclic compounds having 6.04 ≦ pK _a (H ₂ O) ≦ 7.3 in the molecule is also the above-mentioned 6.04 ≦ pK _a (H ₂ O) ≦ 7. It is expected that the same effect as the third additive of .3 can be obtained.

  The third additive is adsorbed on the surface of at least one of the porous electrode and the counter electrode (after the electrolyte layer is provided between the porous electrode and the counter electrode, the interface between the porous electrode or the counter electrode and the electrolyte layer) Therefore, before providing the electrolyte layer between the porous electrode and the counter electrode, the third additive itself, an organic solvent containing the third additive, and the third additive are provided on the surface of the porous electrode or the counter electrode. The third additive may be brought into contact with an electrolytic solution containing an agent. Specifically, for example, the porous electrode or the counter electrode is immersed in an organic solvent containing the third additive, or the organic solvent containing the third additive is sprayed on the surface of the porous electrode or the counter electrode. That's fine.

  When the third additive as described above is used, the molecular weight of the solvent of the electrolytic solution is preferably 47.36 or more. Examples of such a solvent include nitrile solvents such as 3-methoxypropionitrile (MPN), methoxyacetonitrile (MAN), acetonitrile (AN) and valeronitrile (VN), and carbonates such as ethylene carbonate and propylene carbonate. Any of a solvent, a sulfone solvent such as sulfolane, a lactone solvent such as γ-butyrolactone, or a mixture of any two or more of these solvents may be used, but the present invention is not limited thereto.

  By the way, conventionally, volatile organic solvents such as acetonitrile have been used as a solvent for an electrolyte solution of a dye-sensitized solar cell. However, this dye-sensitized solar cell has a problem that when the electrolytic solution is exposed to the atmosphere due to breakage or the like, the electrolytic solution evaporates and causes a failure. In order to solve this problem, in recent years, a hardly volatile molten salt called an ionic liquid has been used instead of a volatile organic solvent as a solvent of an electrolytic solution (for example, Non-Patent Document 3, 4). As a result, the problem of electrolyte volatilization in dye-sensitized solar cells is being improved. However, since the ionic liquid has a much higher viscosity than the conventionally used organic solvent, the photoelectric conversion characteristic of the dye-sensitized solar cell using this ionic liquid is the photoelectric conversion of the conventional dye-sensitized solar cell. The actual situation is inferior to the characteristics. For this reason, the dye-sensitized solar cell which can suppress volatilization of electrolyte solution and can acquire the outstanding photoelectric conversion characteristic is desired. Therefore, the present inventors have intensively studied to solve such problems. In the course of the research, the present inventors will not be able to obtain an improvement effect while seeking an improvement measure for the problem that the photoelectric conversion characteristics deteriorate when an ionic liquid is used as the solvent of the electrolytic solution. As expected, an attempt was made to dilute the ionic liquid with a volatile organic solvent. The result was as expected. In other words, when a solvent obtained by diluting an ionic liquid with a volatile organic solvent is used as the electrolyte, the photoelectric conversion characteristics are improved by decreasing the viscosity of the electrolyte, but the organic solvent is volatilized. Still remains. However, as a result of further attempts to dilute the ionic liquid using various organic solvents in order to proceed with the above verification, the specific combination of the ionic liquid and the organic solvent does not degrade the photoelectric conversion characteristics and performs electrolysis. It has been found that the volatilization of the liquid can be effectively suppressed. This was an unexpected and surprising result. As a result of experimental and theoretical investigations based on the unexpectedly obtained knowledge, electrolysis of an ionic liquid having an electron pair accepting functional group and an organic solvent having an electron pair donating functional group was performed. It came to the conclusion that it was effective to include in the liquid solvent. In this case, a hydrogen bond is formed between the electron pair accepting functional group of the ionic liquid and the electron pair donating functional group of the organic solvent in the solvent of the electrolytic solution. Since the molecules of the ionic liquid and the molecules of the organic solvent are bonded through this hydrogen bond, volatilization of the organic solvent, and thus the electrolytic solution, can be suppressed as compared with the case where the organic solvent is used alone. Further, since the solvent of the electrolytic solution contains an organic solvent in addition to the ionic liquid, the viscosity of the electrolytic solution can be lowered as compared with the case where only the ionic liquid is used as the solvent, and the deterioration of the photoelectric conversion characteristics is prevented. be able to. Thereby, volatilization of the electrolytic solution can be suppressed, and excellent photoelectric conversion characteristics can be obtained.

Here, the above “ionic liquid” includes salts that show a liquid state at 100 ° C. (including those that become a liquid state at room temperature due to supercooling even when the melting point or glass transition temperature is 100 ° C. or higher), Even a salt includes a salt that forms one or more phases by adding a solvent and becomes a liquid state. The ionic liquid may be basically any one as long as it is an ionic liquid having an electron-pair-accepting functional group, and the organic solvent basically has an electron-pair-donating functional group. Any thing is acceptable. The ionic liquid is typically one in which the cation has an electron pair accepting functional group. The ionic liquid is preferably an aromatic amine cation having a quaternary nitrogen atom, with an organic cation having a hydrogen atom in the aromatic ring, 76 Å ³ or more Van der Waals and (van der Waals) volume anions (not only organic anions are, for instance, AlCl ₄ ^- and FeCl ₄ ^- inorganic anions including such) is composed of a, but is not limited thereto. The content of the ionic liquid in the solvent is selected as necessary, but preferably the ionic liquid is contained in the solvent composed of the ionic liquid and the organic solvent in an amount of 15 wt% or more and less than 100 wt%. The electron pair donating functional group of the organic solvent is preferably an ether group or an amino group, but is not limited thereto.

  As described above, when the solvent of the electrolytic solution contains an ionic liquid having an electron pair accepting functional group and an organic solvent having an electron pair accepting functional group, the following effects can be obtained. That is, a hydrogen bond is formed between the electron pair accepting functional group of the ionic liquid and the electron pair donating functional group of the organic solvent in the solvent of the electrolytic solution. Since the molecules of the ionic liquid and the molecules of the organic solvent are bonded through this hydrogen bond, volatilization of the organic solvent, and thus the electrolytic solution, can be suppressed as compared with the case where the organic solvent is used alone. Further, since the solvent of the electrolytic solution contains an organic solvent in addition to the ionic liquid, the viscosity of the electrolytic solution can be lowered as compared with the case where only the ionic liquid is used as the solvent, and the deterioration of the photoelectric conversion characteristics is prevented. be able to. For this reason, the photoelectric conversion element which can suppress volatilization of electrolyte solution and can acquire the outstanding photoelectric conversion characteristic is realizable.

In the present disclosure, the electrolyte layer is made of an iodine redox-based electrolyte containing an additive made of a compound having a stronger interaction with iodine molecules (I ₂ ) than iodide ions (I ⁻ ). Then, this additive interacts preferentially with iodine molecules (I ₂ ). As a result, the reaction represented by the reaction formula of I ₂ + I ⁻ → I ₃ ⁻ is moderately suppressed, and the generation of triiodide ions (I ₃ ⁻ ) is moderately suppressed. For this reason, visible light absorption resulting from I ₃ ⁻ is greatly reduced.

According to the present disclosure, the visible light absorption due to I ₃ ⁻ is significantly reduced, whereby the electrolyte layer can be made colorless and transparent or sufficiently weakly colored. Moreover, since the degree of freedom in selecting the composition of the electrolytic solution is high, high photoelectric conversion characteristics can be obtained by optimizing the composition of the electrolytic solution. A high-performance electronic device can be obtained by using this excellent photoelectric conversion element.

It is sectional drawing which shows the dye-sensitized photoelectric conversion element by 1st Embodiment. It is a basic diagram which shows the density | concentration dependence of the quinuclidine added to electrolyte solution of the photoelectric conversion efficiency Eff of the dye-sensitized photoelectric conversion element of Example 1. FIG. It is a basic diagram which shows the density | concentration dependence of the EMImOAc added to electrolyte solution of the photoelectric conversion efficiency Eff of the dye-sensitized photoelectric conversion element of Example 2. FIG. FIG. 6 is a schematic diagram showing the results of UV-vis measurement of an electrolytic solution in which ADAMAMP is added as an additive, an electrolytic solution obtained by diluting the electrolytic solution 10 times with acetonitrile, and an electrolytic solution obtained by diluting the electrolytic solution 100 times with acetonitrile. is there. It is a schematic diagram showing the relationship between the concentration of ^- the electrolyte plus ADMAMP as an additive concentration and I ₃ of ADMAMP in the electrolytic solution diluted 100 times with acetonitrile. It is sectional drawing which shows the manufacturing method of the dye-sensitized photoelectric conversion element by 2nd Embodiment. It is sectional drawing which shows the manufacturing method of the dye-sensitized photoelectric conversion element by 3rd Embodiment. It is sectional drawing which shows the manufacturing method of the dye-sensitized photoelectric conversion element by 4th Embodiment. It is sectional drawing which shows the manufacturing method of the dye-sensitized photoelectric conversion element by 5th Embodiment. It is sectional drawing which shows the manufacturing method of the dye-sensitized photoelectric conversion element by 6th Embodiment. It is sectional drawing which shows the manufacturing method of the dye-sensitized photoelectric conversion element by 7th Embodiment. It is sectional drawing which shows the manufacturing method of the dye-sensitized photoelectric conversion element by 7th Embodiment. It is sectional drawing which shows the manufacturing method of the dye-sensitized photoelectric conversion element by 8th Embodiment. It is sectional drawing which shows the manufacturing method of the dye-sensitized photoelectric conversion element by 9th Embodiment. It is sectional drawing which shows the manufacturing method of the dye-sensitized photoelectric conversion element by 10th Embodiment. It is sectional drawing which shows the manufacturing method of the dye-sensitized photoelectric conversion element by 12th Embodiment. It is a basic diagram which shows the relationship between the real porosity of the porous film which comprises the electrolyte layer of the dye-sensitized photoelectric conversion element of Reference Examples 19-25, and the normalized photoelectric conversion efficiency. It is a basic diagram which shows the measurement result of the IPCE spectrum of the dye-sensitized photoelectric conversion element of the reference example 25. In the dye-sensitized photoelectric conversion element according to the twelfth embodiment, a schematic diagram showing how light is scattered by the electrolyte layer in comparison with a conventional dye-sensitized photoelectric conversion element using an electrolyte layer made only of an electrolytic solution. It is. It is sectional drawing which shows the manufacturing method of the dye-sensitized photoelectric conversion element by 13th Embodiment. It is sectional drawing which shows the manufacturing method of the dye-sensitized photoelectric conversion element by 13th Embodiment. Is a schematic diagram showing the relationship between the photoelectric conversion efficiency of various additives pK _a dye-sensitized photoelectric conversion element was added to the electrolyte additives Toko. Is a schematic diagram showing the relationship between the internal resistance of the various additives pK _a dye-sensitized photoelectric conversion element was added to the electrolytic solution and the additive added to the electrolyte. It is a basic diagram which shows the solvent seed | species dependence of the electrolyte solution of the effect of an additive. It is sectional drawing which shows the structure of the metal / metal oxide microparticles | fine-particles which comprise a porous electrode in the dye-sensitized photoelectric conversion element by 15th Embodiment.

Hereinafter, modes for carrying out the invention (hereinafter referred to as “embodiments”) will be described. The description will be given in the following order.
1. First Embodiment (Dye-sensitized photoelectric conversion element and manufacturing method thereof)
2. Second Embodiment (Method for Producing Dye-sensitized Photoelectric Conversion Element)
3. Third Embodiment (Method for Producing Dye-sensitized Photoelectric Conversion Element)
4). Fourth Embodiment (Method for Producing Dye-Sensitized Photoelectric Conversion Element)
5. Fifth Embodiment (Dye-sensitized photoelectric conversion element manufacturing method)
6). Sixth Embodiment (Method for Producing Dye-sensitized Photoelectric Conversion Element)
7). Seventh Embodiment (Method for Producing Dye-sensitized Photoelectric Conversion Element)
8). Eighth Embodiment (Method for Producing Dye-sensitized Photoelectric Conversion Element)
9. Ninth Embodiment (Method for Producing Dye-sensitized Photoelectric Conversion Element)
10. Tenth Embodiment (Method for Producing Dye-sensitized Photoelectric Conversion Element)
11. Eleventh Embodiment (Dye-sensitized photoelectric conversion element and method for producing the same)
12 Twelfth embodiment (dye-sensitized photoelectric conversion element and method for producing the same)
13. Thirteenth Embodiment (Method for Producing Dye-sensitized Photoelectric Conversion Element)
14 Fourteenth Embodiment (Dye-sensitized photoelectric conversion element and method for producing the same)
15. Fifteenth embodiment (dye-sensitized photoelectric conversion element and manufacturing method thereof)
16. Sixteenth embodiment (photoelectric conversion element and method for manufacturing the same)

<1. First Embodiment>
[Dye-sensitized photoelectric conversion element]
FIG. 1 is a cross-sectional view of an essential part showing the dye-sensitized photoelectric conversion element.

  As shown in FIG. 1, in this dye-sensitized photoelectric conversion element, a transparent electrode 2 is provided on one main surface of a transparent substrate 1 and has a predetermined planar shape smaller than the transparent electrode 2 on the transparent electrode 2. A porous electrode 3 is provided. One or more kinds of photosensitizing dyes (not shown) are bonded to the porous electrode 3. On the other hand, a conductive layer 5 is provided on one main surface of the counter substrate 4, and a counter electrode 6 is provided on the conductive layer 5. The counter electrode 6 has the same planar shape as the porous electrode 3. An electrolyte layer 7 made of an electrolytic solution is provided between the porous electrode 3 on the transparent substrate 1 and the counter electrode 6 on the counter substrate 4. The outer peripheral portions of the transparent substrate 1 and the counter substrate 4 are sealed with a sealing material 8. The sealing material 8 is in contact with the transparent electrode 2 and the conductive layer 5, but the transparent electrode 2 may be in contact with the transparent substrate 1 by forming the transparent electrode 2 in the same planar shape as the porous electrode 3. 6 may be formed on the entire surface of the conductive layer 5 so as to be in contact with the conductive layer 5.

As the porous electrode 3, a porous semiconductor layer in which semiconductor fine particles are sintered is typically used. The photosensitizing dye is adsorbed on the surface of the semiconductor fine particles. As a material for the semiconductor fine particles, an elemental semiconductor typified by silicon, a compound semiconductor, a semiconductor having a perovskite structure, or the like can be used. These semiconductors are preferably n-type semiconductors in which conduction band electrons become carriers under photoexcitation and generate an anode current. Specifically, for example, titanium oxide (TiO ₂ ), zinc oxide (ZnO), tungsten oxide (WO ₃ ), niobium oxide (Nb ₂ O ₅ ), strontium titanate (SrTiO ₃ ), tin oxide (SnO ₂ ). Such semiconductors are used. Among these semiconductors, it is preferable to use TiO ₂ , especially anatase TiO ₂ . However, the types of semiconductors are not limited to these, and two or more types of semiconductors can be mixed or combined as needed. Further, the shape of the semiconductor fine particles may be any of granular, tube-like, rod-like and the like.

  Although there is no restriction | limiting in particular in the particle size of said semiconductor fine particle, 1-200 nm is preferable at the average particle diameter of a primary particle, Most preferably, it is 5-100 nm. It is also possible to improve the quantum yield by mixing particles having a size larger than that of the semiconductor fine particles and scattering incident light with these particles. In this case, the average size of the particles to be separately mixed is preferably 20 to 500 nm, but is not limited thereto.

  The porous electrode 3 preferably has a large actual surface area including the surface of fine particles facing pores inside the porous semiconductor layer made of semiconductor fine particles so that as many photosensitizing dyes as possible can be bonded. . For this reason, it is preferable that the actual surface area in the state which formed the porous electrode 3 on the transparent electrode 2 is 10 times or more with respect to the area (projection area) of the outer surface of the porous electrode 3, and 100 times More preferably, it is the above. There is no particular upper limit to this ratio, but it is usually about 1000 times.

  Generally, as the thickness of the porous electrode 3 increases and the number of semiconductor fine particles contained per unit projected area increases, the actual surface area increases, and the amount of photosensitizing dye that can be held in the unit projected area increases. Since it increases, the light absorption rate becomes high. On the other hand, when the thickness of the porous electrode 3 is increased, the distance that electrons transferred from the photosensitizing dye to the porous electrode 3 are diffused before reaching the transparent electrode 2, so that the charge in the porous electrode 3 is increased. Electron loss due to recombination also increases. Accordingly, there is a preferable thickness for the porous electrode 3, but this thickness is generally 0.1 to 100 μm, more preferably 1 to 50 μm, and particularly preferably 3 to 30 μm. preferable.

As the electrolytic solution constituting the electrolyte layer 7, an iodine redox-based (redox-based) electrolytic solution containing an additive composed of a compound that has a stronger interaction with iodine molecules than iodide ions is used. As an electrolyte of the iodine redox electrolyte, an electrolyte combining iodine (I ₂ ) and a quaternary ammonium compound such as lithium iodide (LiI), sodium iodide (NaI), imidazolium iodide is suitable. It is a thing. The concentration of the electrolyte salt is preferably 0.05M to 10M, more preferably 0.2M to 3M with respect to the solvent. The concentration of iodine I ₂ or bromine Br ₂ is preferably 0.0005M to 1M, and more preferably 0.001 to 0.5M. Various additives such as 4-tert-butylpyridine and benzimidazoliums may be added for the purpose of improving the open circuit voltage and the short circuit current.

The details of the additive composed of a compound having a stronger interaction with iodine molecules than iodide ions will be described. This additive is roughly classified into a nonionic additive and an ionic additive. Nonionic additives, pK _a (H ₂ O) of pK _a (H ₂ O) is a non-ionic additives and anions of the conjugate acid of more than 9.12 of conjugate acid of the conjugate acid 4.76 or more Ionic additives and the like. Nonionic additives include, for example, the following heterocyclic compounds, cyclic amines, chain amines, diamines, amidines, guanidines, phosphazenes, etc., and one or more of these are used. .

・キノリン（quinoline)

・アクリジン（acridine)

ただし、これらのヘテロ環化合物において、ＲはＮＨ₂ 、ＮＨＲ’、ＮＲ’₂ 、ｐｙｒｒ、Ｒ’は水素（Ｈ）、アルキル（alkyl)、アレーン（arene)である。alkyl はmethyl、ethyl 、n-propyl、i-propyl、n-butyl 、i-butyl 、t-butyl 、hexyl 、octyl などの炭化水素基である。arene は、phenyl、thienyl 、benzylなどの芳香族系構造である。ｐｙｒｒは下記に示す通りである。

[Examples of nonionic additives]
(1) Heterocycles
・ Pyridine

・ Quinoline

・ Acridine

However, in these heterocyclic compounds, R is NH ₂ , NHR ′, NR ′ ₂ , pyrr, and R ′ are hydrogen (H), alkyl, and arene. Alkyl is a hydrocarbon group such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, hexyl, octyl. arene is an aromatic structure such as phenyl, thienyl, or benzyl. pyrr is as shown below.

  Specific examples of these heterocyclic compounds include 4-aminopyridine (4-AMP), 4-N, N-dimethylaminopyridine (4-N, N-dimethylaminopyridine, 4-DMN-Py), 4 -Pyrrolidinopyridine (4-pyrrolidinopyridine, 4-pyrrr-Py), 4-aminoquinoline (4-aminoquinoline), 4-aminoacridine (4-aminoacridine) and the like.

ただし、ＲはＨ、alkyl 、arene である。
・キヌクリジン（quinuclidine)

ただし、ＲはＨ、alkyl 、ＯＨ、ＯＯＣＣＨ₃ である。
・ピペリジン（piperidine)

ただし、ＲはＨ、alkyl 、arene である。
・モルホリン（morpholine)

ただし、ＲはＨである。 (2) Cyclic amine
・ Pyrrolidine

However, R is H, alkyl, and arene.
・ Quinuclidine

Where R is H, alkyl, OH, OOCCH ₃ .
-Piperidine

However, R is H, alkyl, and arene.
・ Morpholine

However, R is H.

  In these cyclic amines, alkyl is a hydrocarbon group such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, hexyl, octyl and the like. arene is an aromatic structure such as phenyl, thienyl, or benzyl.

  Specific examples of these cyclic amines include quinuclidine (Q), 3-hydroxyquinuclidine, 3-acetooxyquinuclidine, pyrrolidine, N- Examples thereof include N-methylpyrrolidine, piperidine, and morpholine.

ただし、Ｒはalkyl 、arene である。
・２級アミン（secondary amine)

ただし、Ｒはalkyl 、arene である。
・３級アミン（tertiary amine)

ただし、Ｒはalkyl 、arene である。 (3) Linear amine
・ Primary amine

R is alkyl or arene.
・ Secondary amine

R is alkyl or arene.
・ Tertiary amine

R is alkyl or arene.

  In these chain amines, alkyl is a hydrocarbon group such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, hexyl, octyl and the like. arene is an aromatic structure such as phenyl, thienyl, or benzyl.

  Specific examples of these chain amines include ammonia, ethanolamine, triethylamine, n-butylamine, di-n-isopropylamine. Etc.

・環状ジアミン（cyclic diamine)

・芳香族ジアミン（aromatic diamine)

ただし、これらのジアミンにおいて、ＲはＨ、alkyl 、arene である。alkyl はmethyl、ethyl 、n-propyl、i-propyl、n-butyl 、i-butyl 、t-butyl 、hexyl 、octyl などの炭化水素基である。arene は、phenyl、thienyl 、benzylなどの芳香族系構造である。炭化水素基は置換されていてもよい。 (4) Diamine
・ Linear diamine

・ Cyclic diamine

・ Aromatic diamine

However, in these diamines, R is H, alkyl, or arene. Alkyl is a hydrocarbon group such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, hexyl, octyl. arene is an aromatic structure such as phenyl, thienyl, or benzyl. The hydrocarbon group may be substituted.

  Specific examples of these diamines include 1,3-propanediamine, 3,7-dibutyl-3,7-diazabicyclo [3.3.1] nonane (3,7-dibutyl- 3,7-diazabicyclo [3.3.1] nonane), 1,8-bis (dimethylamino) naphthalene, and the like.

ただし、これらのアミジンにおいて、ＲはＨ、alkyl 、arene である。alkyl はmethyl、ethyl 、n-propyl、i-propyl、n-butyl 、i-butyl 、t-butyl 、hexyl 、octyl などの炭化水素基である。arene は、phenyl、thienyl 、benzylなどの芳香族系構造である。炭化水素基は置換されていてもよい。 (5) Amidine

However, in these amidines, R is H, alkyl, or arene. Alkyl is a hydrocarbon group such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, hexyl, octyl. arene is an aromatic structure such as phenyl, thienyl, or benzyl. The hydrocarbon group may be substituted.

  Specific examples of these amidines include acetamidine, 1,5-diazabicyclo [4.3.0] non-5-ene (1,5-diazabicyclo [4.3.0] non-5-ene). 1,8-diazabicyclo [5.4.0] undec-7-ene (1,8-diazabicyclo [5.4.0] undec-7-ene) and the like.

ただし、これらのグアニジンにおいて、ＲはＨ、alkyl 、arene である。alkyl はmethyl、ethyl 、n-propyl、i-propyl、n-butyl 、i-butyl 、t-butyl 、hexyl 、octyl などの炭化水素基である。arene は、phenyl、thienyl 、benzylなどの芳香族系構造である。炭化水素基は置換されていてもよい。 (6) Guanidine

However, in these guanidines, R is H, alkyl, or arene. Alkyl is a hydrocarbon group such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, hexyl, octyl. arene is an aromatic structure such as phenyl, thienyl, or benzyl. The hydrocarbon group may be substituted.

  Specific examples of these guanidines include 1,1,3,3-tetramethylguanidine, 1,5,7-triazabicyclo [4.4.0] dec -5-ene (1,5,7-triazabicyclo [4.4.0] dec-5-ene), 7-methyl-1,5,7-triazabicyclo [4.4.0] dec-5-ene ( 7-Methyl-1,5,7-triazabicyclo [4.4.0] dec-5-ene).

ただし、これらのホスファゼンにおいて、ＲはＨ、alkyl 、arene である。ＮＲ₂ はｐｙｒｒ、ｔｍｇでもよい。alkyl はmethyl、ethyl 、n-propyl、i-propyl、n-butyl 、i-butyl 、t-butyl 、hexyl 、octyl などの炭化水素基である。arene は、phenyl、thienyl
、benzylなどの芳香族系構造である。炭化水素基は置換されていてもよい。ｔｍｇは下記に示す通りである。

(7) Phosphazene

However, in these phosphazenes, R is H, alkyl, or arene. NR ₂ may be pyrr or tmg. Alkyl is a hydrocarbon group such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, hexyl, octyl. arene is phenyl, thienyl
Aromatic structures such as benzyl. The hydrocarbon group may be substituted. tmg is as shown below.

  Specific examples of these phosphazenes include t-butylimino-tris (dimethylamino) phosphorane, 2-t-butylimino-2-diethylamino-1,3-dimethylperhydro- 1,3,2-diazaphosphorine (2-t-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine).

ただし、ＲはＨ、alkyl である。 [Examples of ionic additives]
The ionic additive consists of an anion and a cation. Examples of anions include the following.
(1) Carboxylate anion
It is a conjugated anion of COO-H acid and is as follows.

However, R is H and alkyl.

ただし、Ｒはalkyl 、fluoroalkyl 、arene である。 (2) Alkoxy anion
It is a conjugated anion of OH acid and is as follows.

However, R is alkyl, fluoroalkyl, arene.

ただし、Ｒはalkyl 、fluoroalkyl 、arene である。 (3) Mercapto anion
It is a conjugated anion of S—H acid and is as follows.

However, R is alkyl, fluoroalkyl, arene.

ただし、Ｒはalkyl 、fluoroalkyl 、arene である。 (4) Carbon anion
It is a conjugated anion of C—H acid and is as follows.

However, R is alkyl, fluoroalkyl, arene.

ただし、Ｒはalkyl 、arene である。 (5) Amide anion
It is a conjugated anion of NH acid and is as follows.

R is alkyl or arene.

In these anions, alkyl is a hydrocarbon group such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, hexyl, octyl and the like. Fluoroalkyl is a fluorinated hydrocarbon such as CF ₃ or C ₂ F ₅ . arene is an aromatic structure such as phenyl, thienyl, or benzyl.

  Specific examples of these anions include acetate, 2,2,2-tetrafluoroethanoate, phenolate, ethyl mercaptate, acetyl Examples thereof include acetonate, hexafluoroacetylacetonate, imidazolate and 1H-tetrazolate.

ただし、これらのカチオンにおいて、ＲはＨ、alkyl 、arene である。alkyl はmethyl、ethyl 、n-propyl、i-propyl、n-butyl 、i-butyl 、t-butyl 、hexyl 、octyl などの炭化水素基である。arene は、phenyl、thienyl 、benzylなどの芳香族系化合物である。炭化水素基は置換されていてもよい。 The cation of the ionic additive may be basically any one as long as it is chemically stable, and examples thereof include the following cations.

However, in these cations, R is H, alkyl or arene. Alkyl is a hydrocarbon group such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, hexyl, octyl. arene is an aromatic compound such as phenyl, thienyl, or benzyl. The hydrocarbon group may be substituted.

  Specific examples of these cations include ammonium, imidazolium, pyrrolidinium, pyridinium, sulfonium, phosphonium, piperidinium, and morphonium. Etc.

４−ピロリジノピリジン（4-pyrrolidinopyridine,４−ｐｙｒｒ−Ｐｙ）

キヌクリジン（quinuqulidine,Ｑ）

４−アミノピリジン（4-aminopyridine,４ＡＭＰ）

が好ましい。また、イオン性添加剤としては、上記の中でも取り分け、
１−エチル−３−メチルイミダゾリウムアセテート（1-ethyl-3-methylimidazoliumacetate, ＥＭＩｍＯＡｃ）

１−エチル−３−メチルイミダゾリウムデカノネート（1-ethyl-3-methylimidazoliumdecanonate,ＥＭＩｍＤＡ）

が好ましい。 As nonionic additives, especially among the above,
4-N, N-dimethylaminopyridine (4-N, N-dimethylaminopyridine, 4-DMN-Py)

4-pyrrolidinopyridine (4-pyrrolidinopyridine, 4-pyrr-Py)

Quinuqulidine (Q)

4-aminopyridine (4AMP)

Is preferred. In addition, as an ionic additive, among the above,
1-ethyl-3-methylimidazolium acetate (EMImOAc)

1-ethyl-3-methylimidazolium decanonate (EMImDA)

Is preferred.

Table The pK _a (H ₂ O) anionic OAc and DA of the four types of non-ionic additives 4 AMP,4-DMN-Py,Q and 4-pyrr-Py and the above-described two kinds of ionic additive It is shown in 1. Table 1 shows the values of pK _a (AN) in acetonitrile (AN) for reference.

As shown in Table 1, none of the 4 AMP,4-DMN-Py and Q is a non-ionic additives, pK _a (H ₂ O) is 9.12 or more. 4-pyrr-Py of pK _a (H ₂ O) is unknown, since the 4-pyrr-Py of pK _a (AN) is equivalent to pK _a (AN) of Q, Q of pK _a ( H ₂ O) is considered to be equivalent, and is therefore considered to be greater than 9.12. In addition, each of the anions OAc and DA of the ionic additives EMImOAc and EMImDA is 4.76 or more.

  As the solvent constituting the electrolytic solution, generally, water, alcohols, ethers, esters, carbonate esters, lactones, carboxylic acid esters, phosphate triesters, heterocyclic compounds, nitriles , Ketones, amides, nitromethane, halogenated hydrocarbons, dimethyl sulfoxide, sulfolane, N-methylpyrrolidone, 1,3-dimethylimidazolidinone, 3-methyloxazolidinone, hydrocarbons and the like are used.

  As a solvent constituting the electrolytic solution, an ionic liquid may be used, and by doing so, the problem of volatilization of the electrolytic solution can be improved. A conventionally well-known thing can be used as an ionic liquid, Although it chooses as needed, a specific example is as follows.

EMImTCB: 1-ethyl-3-methylimidazolium tetracyanoborate
EMImTFSI: 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide
EMImFAP: 1-ethyl-3-methylimidazolium tris (pentafluoroethyl) trifluorophosphate
EMImBF ₄ : 1-ethyl-3-methylimidazolium tetrafluoroborate
EMImOTf (1-ethyl-3-methylimidazolium trifluorosulfonate)
・ P ₂₂₂ MOMTFSI (triethyl (methoxymethyl) phosphonium bis (trifluoromethylsufonyl) imide)

  The transparent substrate 1 is not particularly limited as long as it has a material and a shape that easily transmit light, and various substrate materials can be used, but a substrate material that has a particularly high visible light transmittance is used. Is preferred. In addition, a material having a high blocking performance for blocking moisture and gas from entering the dye-sensitized photoelectric conversion element from the outside, and excellent in solvent resistance and weather resistance is preferable. Specifically, as the material of the transparent substrate 1, transparent inorganic materials such as quartz and glass, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polystyrene, polyethylene, polypropylene, polyphenylene sulfide, polyvinylidene fluoride, acetylcellulose, bromo Examples thereof include transparent plastics such as modified phenoxy, aramids, polyimides, polystyrenes, polyarylates, polysulfones, and polyolefins. The thickness in particular of the transparent substrate 1 is not restrict | limited, It can select suitably considering the light transmittance and the performance which interrupts | blocks the inside and outside of a photoelectric conversion element.

The transparent electrode 2 provided on the transparent substrate 1 is more preferable as the sheet resistance is smaller, specifically 500Ω / □ or less, more preferably 100Ω / □ or less. A known material can be used as the material for forming the transparent electrode 2 and is selected as necessary. Specifically, the material for forming the transparent electrode 2 is indium-tin composite oxide (ITO), fluorine-doped tin oxide (IV) SnO ₂ (FTO), tin oxide (IV) SnO ₂ , oxidation Zinc (II) ZnO, indium-zinc composite oxide (IZO), etc. are mentioned. However, the material which forms the transparent electrode 2 is not limited to these, It can also use combining 2 or more types.

  The photosensitizing dye to be bonded to the porous electrode 3 is not particularly limited as long as it exhibits a sensitizing action, and organic metal complexes, organic dyes, metal / semiconductor nanoparticles, and the like can be used. Those having an acid functional group adsorbed on the surface of the electrode 3 are preferred. In general, the photosensitizing dye preferably has a carboxy group, a phosphoric acid group, and the like, and among them, those having a carboxy group are particularly preferable. Specific examples of the photosensitizing dye include, for example, xanthene dyes such as rhodamine B, rose bengal, eosin, erythrosine, cyanine dyes such as merocyanine, quinocyanine, and cryptocyanine, phenosafranine, fog blue, thiocin, and methylene blue. Basic dyes, porphyrin compounds such as chlorophyll, zinc porphyrin, magnesium porphyrin, and others include azo dyes, phthalocyanine compounds, coumarin compounds, pyridine complex compounds, anthraquinone dyes, polycyclic quinone dyes, Examples thereof include π-conjugated polymers such as triphenylmethane dyes, indoline dyes, perylene dyes, polythiophenes, 2 to 20 monomers of the monomers, and quantum dots such as CdS and CdSe. Among these, the ligand (ligand) includes a pyridine ring or an imidazolium ring, and a dye of at least one metal complex selected from the group consisting of Ru, Os, Ir, Pt, Co, Fe, and Cu is High quantum yield is preferable. In particular, cis-bis (isothiocyanato) -N, N-bis (2,2′-dipyridyl-4,4′-dicarboxylic acid) -ruthenium (II) or tris (isothiocyanato) -ruthenium (II) — A dye molecule having 2,2 ': 6', 2 "-terpyridine-4,4 ', 4" -tricarboxylic acid as a basic skeleton has a wide absorption wavelength range and is preferable. However, the photosensitizing dye is not limited to these. Typically, one of these is used as the photosensitizing dye, but two or more kinds of photosensitizing dyes may be mixed and used. When two or more types of photosensitizing dyes are used in combination, the photosensitizing dye is preferably an inorganic complex dye having a property of causing MLCT (Metal to Ligand Charge Transfer) held in the porous electrode 3. And an organic molecular dye having the property of intramolecular CT (Charge Transfer) held by the porous electrode 3. In this case, the inorganic complex dye and the organic molecular dye are adsorbed on the porous electrode 3 in different conformations. The inorganic complex dye preferably has a carboxy group or a phosphono group as a functional group bonded to the porous electrode 3. In addition, the organic molecular dye preferably has a carboxy group or a phosphono group and a cyano group, an amino group, a thiol group, or a thione group as functional groups bonded to the porous electrode 3 on the same carbon. The inorganic complex dye is, for example, a polypyridine complex, and the organic molecular dye is, for example, an aromatic polycyclic conjugated molecule having an electron donating group and an electron accepting group and having intramolecular CT properties.

  The method for adsorbing the photosensitizing dye to the porous electrode 3 is not particularly limited. For example, the photosensitizing dye may be an alcohol, nitrile, nitromethane, halogenated hydrocarbon, ether, dimethyl sulfoxide, amide, It is dissolved in a solvent such as N-methylpyrrolidone, 1,3-dimethylimidazolidinone, 3-methyloxazolidinone, esters, carbonates, ketones, hydrocarbons, water, and the porous electrode 3 is immersed in the solution. A solution containing a photosensitizing dye can be applied onto the porous electrode 3. Further, deoxycholic acid or the like may be added for the purpose of reducing association between molecules of the photosensitizing dye. If necessary, an ultraviolet absorber can be used in combination.

  After the photosensitizing dye is adsorbed on the porous electrode 3, the surface of the porous electrode 3 may be treated with amines for the purpose of promoting the removal of the excessively adsorbed photosensitizing dye. Examples of amines include pyridine, 4-tert-butylpyridine, polyvinylpyridine, and the like. When these are liquid, they may be used as they are, or may be used after being dissolved in an organic solvent.

  Any material can be used as the material for the counter electrode 6 as long as it is a conductive substance. However, if a conductive layer is formed on the side facing the electrolyte layer 7 of the insulating material, this can also be used. Is possible. As the material of the counter electrode 6, it is preferable to use an electrochemically stable material. Specifically, it is desirable to use platinum, gold, carbon, a conductive polymer, or the like.

  Further, in order to improve the catalytic action for the reduction reaction at the counter electrode 6, it is preferable that the surface of the counter electrode 6 in contact with the electrolyte layer 7 is formed so that a fine structure is formed and the actual surface area is increased. . For example, the surface of the counter electrode 6 is preferably formed in a platinum black state if it is platinum, or in a porous carbon state if it is carbon. Platinum black can be formed by anodization of platinum or chloroplatinic acid treatment, and porous carbon can be formed by a method such as sintering of carbon fine particles or firing of an organic polymer.

  The counter electrode 6 is formed on the conductive layer 5 formed on one main surface of the counter substrate 4, but is not limited thereto. As the material of the counter substrate 4, opaque glass, plastic, ceramic, metal, or the like may be used, or a transparent material such as transparent glass or plastic may be used. As the conductive layer 5, the same material as that of the transparent electrode 2 can be used, and one formed of an opaque conductive material can also be used.

  As a material of the sealing material 8, it is preferable to use a material having light resistance, insulation, moisture resistance, and the like. Specific examples of the material of the sealing material 8 include epoxy resin, ultraviolet curable resin, acrylic resin, polyisobutylene resin, EVA (ethylene vinyl acetate), ionomer resin, ceramic, various heat-sealing films, and the like.

  Moreover, when inject | pouring electrolyte solution, although an injection port is required, if it is not on the porous electrode 3 and the counter electrode 6 of the part facing this, the place of an injection port will not be specifically limited. The method for injecting the electrolytic solution is not particularly limited, but a method of injecting the solution under reduced pressure inside the photoelectric conversion element in which the outer periphery is sealed in advance and the solution injection port is opened is preferable. In this case, a method of dropping a few drops of the solution at the injection port and injecting the solution by capillary action is simple. In addition, the injection operation can be performed under reduced pressure or under heating as necessary. After the solution is completely injected, the solution remaining at the inlet is removed and the inlet is sealed. Although there is no restriction | limiting in particular also in this sealing method, If necessary, it can also seal by affixing a glass plate or a plastic substrate with a sealing agent. In addition to this method, an electrolytic solution can be dropped on a substrate and bonded together under reduced pressure as in a liquid crystal drop injection (ODF: One Drop Filling) process of a liquid crystal panel. After sealing, in order to fully immerse the electrolyte in the porous electrode 3, it is possible to perform heating and pressurizing operations as necessary.

[Method for producing dye-sensitized photoelectric conversion element]
Next, the manufacturing method of this dye-sensitized photoelectric conversion element is demonstrated.
First, the transparent electrode 2 is formed by forming a transparent conductive layer on one main surface of the transparent substrate 1 by sputtering or the like.

  Next, the porous electrode 3 is formed on the transparent electrode 2 of the transparent substrate 1. The method for forming the porous electrode 3 is not particularly limited, but in consideration of physical properties, convenience, production cost, etc., it is preferable to use a wet film forming method. In the wet film forming method, a paste-form dispersion liquid in which semiconductor fine particle powder or sol is uniformly dispersed in a solvent such as water is prepared, and this dispersion liquid is applied or printed on the transparent electrode 2 of the transparent substrate 1. Is preferred. There is no restriction | limiting in particular in the application method or printing method of a dispersion liquid, A well-known method can be used. Specifically, as a coating method, for example, a dipping method, a spray method, a wire bar method, a spin coating method, a roller coating method, a blade coating method, a gravure coating method, or the like can be used. Moreover, as a printing method, a relief printing method, an offset printing method, a gravure printing method, an intaglio printing method, a rubber plate printing method, a screen printing method, etc. can be used.

When anatase-type TiO ₂ is used as the material for the semiconductor fine particles, this anatase-type TiO ₂ may be a commercially available product in the form of powder, sol, or slurry, or is known such as hydrolyzing titanium oxide alkoxide. A material having a predetermined particle diameter may be formed by a method. When using a commercially available powder, it is preferable to eliminate secondary agglomeration of the particles, and it is preferable to pulverize the particles using a mortar, ball mill or the like when preparing the paste-like dispersion. At this time, acetylacetone, hydrochloric acid, nitric acid, a surfactant, a chelating agent, and the like can be added to the paste-like dispersion in order to prevent the particles from which secondary aggregation has been eliminated from aggregating again. In addition, in order to increase the viscosity of the paste-like dispersion, polymers such as polyethylene oxide and polyvinyl alcohol, or various thickeners such as a cellulose-based thickener can be added to the paste-like dispersion.

  The porous electrode 3 is formed by applying or printing the semiconductor fine particles on the transparent electrode 2 and then electrically connecting the semiconductor fine particles to improve the mechanical strength of the porous electrode 3, thereby improving the adhesion with the transparent electrode 2. In order to improve, baking is preferable. Although there is no restriction | limiting in particular in the range of baking temperature, Since the electrical resistance of the transparent electrode 2 will become high when the temperature is raised too much, and also the transparent electrode 2 may melt | fuse, 40-700 degreeC is preferable normally, 40 -650 degreeC is more preferable. The firing time is not particularly limited, but is usually about 10 minutes to 10 hours.

  For example, a dip treatment with a titanium tetrachloride aqueous solution or a titanium oxide ultrafine particle sol having a diameter of 10 nm or less may be performed for the purpose of increasing the surface area of the semiconductor fine particles or increasing the necking between the semiconductor fine particles. When a plastic substrate is used as the transparent substrate 1 that supports the transparent electrode 2, the porous electrode 3 is formed on the transparent electrode 2 using a paste-like dispersion containing a binder, and the transparent electrode 2 is heated by pressing. It is also possible to pressure-bond to.

  Next, the transparent substrate 1 on which the porous electrode 3 is formed is immersed in a photosensitizing dye solution in which a photosensitizing dye is dissolved in a predetermined organic solvent, whereby the photosensitizing dye is applied to the porous electrode 3. Combine.

  On the other hand, after the conductive layer 5 is formed on the entire surface of the counter substrate 4 by sputtering, for example, a counter electrode 6 having a predetermined planar shape is formed on the conductive layer 5. The counter electrode 6 can be formed, for example, by forming a film to be the material of the counter electrode 6 on the entire surface of the conductive layer 5 by sputtering, for example, and then patterning the film by etching.

Next, the transparent substrate 1 and the counter substrate 4 are arranged so that the porous electrode 3 and the counter electrode 6 face each other at a predetermined interval, for example, 1 to 100 μm, preferably 1 to 50 μm. And the sealing material (not shown) is formed in the outer peripheral part of the transparent substrate 1 and the opposing board | substrate 4, the space where the electrolyte layer 7 is enclosed is made, and the liquid injection previously formed in the transparent substrate 1, for example in this space An electrolyte solution is injected from a mouth (not shown) to form the electrolyte layer 7. This electrolyte can be prepared by simply adding an additive made of a compound that has a stronger interaction with iodine molecules than iodide ions to the iodine redox electrolyte, or mixing the additive with a color such as iodine in advance. Use a mixture after interacting with ingredients. Thereafter, the liquid injection port is closed.
Thus, the target dye-sensitized photoelectric conversion element is manufactured.

[Operation of dye-sensitized photoelectric conversion element]
Next, the operation of this dye-sensitized photoelectric conversion element will be described.
When light is incident, the dye-sensitized photoelectric conversion element operates as a battery having the counter electrode 6 as a positive electrode and the transparent electrode 2 as a negative electrode. The principle is as follows. Here, FTO is used as the material of the transparent electrode 2, TiO ₂ is used as the material of the porous electrode 3, and redox species of I ⁻ / I ₃ ⁻ are used as the redox pair. Further, it is assumed that one kind of photosensitizing dye is bonded to the porous electrode 3.

When a photosensitizing dye that has passed through the transparent substrate 1 and the transparent electrode 2 and has entered the porous electrode 3 and has been bonded to the porous electrode 3 absorbs the photons, the electrons in the photosensitizing dye are released from the ground state (HOMO). Excited to an excited state (LUMO). The electrons thus excited are drawn out to the conduction band of TiO ₂ constituting the porous electrode 3 through the electrical coupling between the photosensitizing dye and the porous electrode 3, and pass through the porous electrode 3. It reaches the transparent electrode 2.

On the other hand, the photosensitizing dye that has lost the electrons receives electrons from the reducing agent I ^{− in} the electrolyte layer 7 by the following reaction, and the electrolyte layer 7 has the oxidizing agent I ₃ ⁻ (I ₂ and I ^−. To form a conjugate).
2I ⁻ → I ₂ + 2e ^{−
_{I 2 + I - → I 3}} -

The oxidant thus generated reaches the counter electrode 6 by diffusion, receives electrons from the counter electrode 6 by the reverse reaction of the above reaction, and is reduced to the original reducing agent.
^{_{I 3 - → I 2 + I}} -
I ₂ + 2e ^- → 2I ^-

  The electrons sent from the transparent electrode 2 to the external circuit return to the counter electrode 6 after performing electrical work in the external circuit. In this way, light energy is converted into electrical energy without leaving any change in the photosensitizing dye or the electrolyte layer 7.

<Example 1>
A dye-sensitized photoelectric conversion element was produced as follows.
The paste-like dispersion of TiO ₂ that is a raw material for forming the porous electrode 3 is referred to “the latest technology of dye-sensitized solar cells” (supervised by Hironori Arakawa, 2001, CMC Co., Ltd.). Produced. That is, first, 125 ml of titanium isopropoxide was gradually added dropwise to 750 ml of 0.1 M nitric acid aqueous solution while stirring at room temperature. After dropping, the mixture was transferred to a constant temperature bath at 80 ° C. and stirring was continued for 8 hours. As a result, a cloudy translucent sol solution was obtained. The sol solution was allowed to cool to room temperature, filtered through a glass filter, and a solvent was added to make the solution volume 700 ml. The obtained sol solution was transferred to an autoclave, subjected to a hydrothermal reaction at 220 ° C. for 12 hours, and then subjected to dispersion treatment by ultrasonic treatment for 1 hour. Next, this solution was concentrated at 40 ° C. using an evaporator to prepare a TiO ₂ content of 20 wt%. To the concentrate sol solution was added to 20% content of polyethylene glycol of TiO ₂ weight (molecular weight 500,000), 30% of the grain diameter 200nm of TiO ₂ by weight and anatase TiO _2, stirring deaerator To obtain a pasty dispersion of TiO ₂ with increased viscosity.

The paste dispersion of TiO ₂ was applied onto the FTO layer as the transparent electrode 2 by a blade coating method to form a fine particle layer having a size of 5 mm × 5 mm and a thickness of 200 μm. Thereafter, the TiO ₂ fine particles were sintered on the FTO layer by holding at 500 ° C. for 30 minutes. A 0.1 M titanium chloride (IV) TiCl ₄ aqueous solution was added dropwise to the sintered TiO ₂ film, kept at room temperature for 15 hours, washed, and fired again at 500 ° C. for 30 minutes. Thereafter, the ultraviolet light irradiation apparatus is used to irradiate the TiO ₂ sintered body with ultraviolet light for 30 minutes, and impurities such as organic substances contained in the TiO ₂ sintered body are oxidatively decomposed and removed by the photocatalytic action of TiO _2. The porous electrode 3 was obtained by performing a treatment for increasing the activity of the TiO ₂ sintered body.

As a photosensitizing dye, 23.8 mg of Z907 represented by the following structural formula, which was sufficiently purified, was dissolved in 50 ml of a mixed solvent in which acetonitrile and tert-butanol were mixed at a volume ratio of 1: 1, and photosensitizing was performed. A dye-sensitive solution was prepared.

The photosensitizing dye solution thus prepared was soaked into a nonwoven fabric having the same planar shape as the porous electrode 3. Then, the nonwoven fabric containing the photosensitizing dye solution is pressed against the porous electrode 3 at room temperature, and the photosensitizing dye solution is supplied from the nonwoven fabric to the porous electrode 3, and the photosensitizing dye is applied to the surface of the TiO ₂ fine particles. Was adsorbed. Next, the porous electrode 3 was washed sequentially with an acetonitrile solution of 4-tert-butylpyridine and acetonitrile, and then the solvent was evaporated in the dark and dried.

  The counter electrode 6 is formed by sequentially depositing a 50 nm-thick chromium layer and a 100 nm-thick platinum layer on a FTO layer, in which a liquid injection port having a diameter of 0.5 mm is formed in advance, by sputtering. An isopropyl alcohol (2-propanol) solution was spray coated and formed by heating at 385 ° C. for 15 minutes.

  Next, the transparent substrate 1 and the counter substrate 4 are arranged so that the porous electrode 3 and the counter electrode 6 face each other, and the outer periphery is sealed with an ionomer resin film having a thickness of 30 μm and an acrylic ultraviolet curable resin. .

Meanwhile, 2.0 g of 3-methoxypropionitrile (MPN) as a solvent, 0.030 g of sodium iodide NaI, 1.0 g of 1-propyl-2,3-dimethylimidazolium iodide, 0.10 g of iodine I ₂ In addition to 0.054 g of 2-NH2-Py as an additive, quinuclidine (Q) was dissolved to prepare an electrolytic solution.

  This electrolytic solution was injected from a liquid injection port of a dye-sensitized photoelectric conversion element prepared in advance using a liquid feed pump, and the pressure inside the element was reduced to expel bubbles inside the element. Thus, the electrolyte layer 7 is formed. Next, the liquid inlet was sealed with an ionomer resin film, an acrylic resin, and a glass substrate to complete a dye-sensitized photoelectric conversion element.

<Example 2>
In Example 2, a dye-sensitized photoelectric conversion element was produced in the same manner as in Example 1 except that an electrolyte prepared using EMImOAc instead of quinuclidine was used as an additive to be added to the electrolyte.

The current-voltage characteristics of the dye-sensitized photoelectric conversion element were measured by changing the concentration of quinuclidine (Q) added to the electrolyte solution constituting the electrolyte layer 7 in the dye-sensitized photoelectric conversion element of Example 1. The measurement was performed by irradiating the dye-sensitized photoelectric conversion element with artificial sunlight (AM1.5, 100 mW / cm ² ). Table 2 and FIG. 2 show the measurement results of the photoelectric conversion efficiency (Eff) of the dye-sensitized photoelectric conversion element. As shown in Table 2 and FIG. 2, in the measured range, the photoelectric conversion efficiency (Eff) tends to decrease as the Q concentration increases after taking a maximum at around 0.25M. On the other hand, when the color of the electrolyte was observed when the Q concentration was changed, it was almost colorless and transparent when the Q concentration was from 0.50 M to 1.00 M, and within that range, the higher the Q concentration, the higher the transparency, and below that. The lower the Q concentration, the stronger the degree of brown coloration.

In the dye-sensitized photoelectric conversion element of Example 2, the current-voltage characteristics of the dye-sensitized photoelectric conversion element were measured by changing the concentration of EMImOAc added to the electrolyte solution constituting the electrolyte layer 7. The measurement was performed by irradiating the dye-sensitized photoelectric conversion element with artificial sunlight (AM1.5, 100 mW / cm ² ). Table 3 and FIG. 3 show the measurement results of photoelectric conversion efficiency (Eff) of this dye-sensitized photoelectric conversion element. As shown in Table 3 and FIG. 3, in the measured range, the photoelectric conversion efficiency (Eff) tends to decrease as the EMImOAc concentration increases after taking a maximum in the vicinity of 0.25 M to 0.5 M. On the other hand, when the color of the electrolyte solution was observed when the EMImOAc concentration was changed, it was almost colorless and transparent when the EMImOAc concentration was 1.00 M, and the brown coloring degree was lower as the EMImOAc concentration was lower than the EMImOAc concentration range. Strengthened.

Next, in order to investigate the relationship between the concentration of the additive in the electrolytic solution and triiodide ion (I ₃ ⁻ ) which is a causative substance that the electrolytic solution is colored brown, UV-vis measurement was performed. The measurement was carried out by using an electrolyte (4 times dilution) using 4DMAPMP (4-dimethylaminopyridine) instead of quinuclidine (Q) used as an additive in the electrolyte of Example 1, and this electrolyte was diluted 10 times with acetonitrile. Three types of electrolyte solutions were prepared: an electrolyte solution (diluted 10 times) and an electrolyte solution (diluted 100 times) obtained by diluting the electrolyte solution 100 times with acetonitrile. FIG. 4 shows the results of UV-vis measurement of these electrolytes. Using the absorbance at a wavelength of 360 nm corresponding to the absorption wavelength of I ₃ ⁻ of the electrolyte diluted 100 times with acetonitrile, the concentration of I ₃ ⁻ ([I ₃ ⁻ ]) with respect to the concentration of 4DMPAMP ([4DMAPMP]) The plotted results are shown in FIG. As a result, the relational expression [I ₃ ⁻ ] = A−B [4DMPAMP] was obtained. A in this formula is [I ₃ ⁻ ] without addition of additive, and B = 0.2195. As shown in FIG. 5, it can be seen that [I ₃ ⁻ ] decreases linearly as [4 DMAMP] increases.

  As described above, according to the first embodiment, iodine redox electrolysis including an additive made of a compound having a stronger interaction with iodine molecules than iodide ions as the electrolyte solution constituting the electrolyte layer 7. By using the liquid, it is possible to realize a dye-sensitized photoelectric conversion element capable of making the electrolyte layer 7 colorless and transparent or weakly colored without significantly reducing the photoelectric conversion characteristics.

<2. Second Embodiment>
[Method for producing dye-sensitized photoelectric conversion element]
In the method of manufacturing the dye-sensitized photoelectric conversion element according to the second embodiment, the photosensitizing dye is adsorbed to the porous electrode 3 as follows.

  First, as shown in FIG. 6A, a transparent substrate 1 on which a transparent electrode 2 is formed is placed on a table (not shown), and a holding material that holds a photosensitizing dye solution in which a photosensitizing dye is dissolved in a predetermined solvent. 9 is positioned above the porous electrode 3. In FIG. 6A, the photosensitizing dye contained in the photosensitizing dye solution is schematically shown by spotting (hereinafter, the photosensitizing dye is similarly schematically shown by spotting). The planar shape of the holding material 9 has almost the same shape as the porous electrode 3. The holding material 9 may be any material as long as it has the ability to hold the photosensitizing dye solution, and is, for example, a nonwoven fabric, paper, sponge, paste, gel, or the like.

Next, as shown in FIG. 6B, the holding material 9 is lowered and brought into contact with the porous electrode 3, and then the holding material 9 is pressed against the porous electrode 3 from above by a pressing plate (not shown). At this time, the holding material 9 is compressed, so that the photosensitizing dye solution held therein is pushed out to the pressing surface and supplied to the porous electrode 3. Thus, the photosensitizing dye solution supplied to the porous electrode 3 reaches the inside of the porous electrode 3 and adsorbs the photosensitizing dye. In this case, as compared with the conventional case, the transparent substrate 1 on which the porous electrode 3 is formed is immersed in the photosensitizing dye solution to adsorb the photosensitizing dye to the porous electrode 3. The amount of the photosensitizing dye solution can be greatly reduced. Further, in the method of immersing the transparent substrate 1 on which the porous electrode 3 is formed in the photosensitizing dye solution, there is a possibility that the photosensitizing dye solution is contaminated or the solution composition is changed during repeated use. On the other hand, in the above-described method, since the photosensitizing dye solution is supplied to the porous electrode 3 by pressing the holding material 9 holding the photosensitizing dye solution against the porous electrode 3, contamination is caused each time. In addition, a photosensitizing dye solution that is fresh and has a constant composition can be supplied to the porous electrode 3.
Thereafter, as shown in FIG. 6C, the holding material 9 is raised.

  The manufacturing method of the dye-sensitized photoelectric conversion element other than the above is the same as the manufacturing method of the dye-sensitized photoelectric conversion element according to the first embodiment.

<Example 3>
A dye-sensitized photoelectric conversion element was produced as follows.
The paste-like dispersion of TiO ₂ that is a raw material for forming the porous electrode 3 is referred to “the latest technology of dye-sensitized solar cells” (supervised by Hironori Arakawa, 2001, CMC Co., Ltd.). Produced. That is, first, 125 ml of titanium isopropoxide was gradually added dropwise to 750 ml of 0.1 M nitric acid aqueous solution while stirring at room temperature. After dropping, the mixture was transferred to a constant temperature bath at 80 ° C. and stirring was continued for 8 hours. As a result, a cloudy translucent sol solution was obtained. The sol solution was allowed to cool to room temperature, filtered through a glass filter, and a solvent was added to make the solution volume 700 ml. The obtained sol solution was transferred to an autoclave, subjected to a hydrothermal reaction at 220 ° C. for 12 hours, and then subjected to dispersion treatment by ultrasonic treatment for 1 hour. Next, this solution was concentrated at 40 ° C. using an evaporator to prepare a TiO ₂ content of 20 wt%. To the concentrate sol solution was added to 20% content of polyethylene glycol of TiO ₂ weight (molecular weight 500,000), 30% of the grain diameter 200nm of TiO ₂ by weight and anatase TiO _2, stirring deaerator To obtain a pasty dispersion of TiO ₂ with increased viscosity.

The paste dispersion of TiO ₂ was applied onto the FTO layer as the transparent electrode 2 by a blade coating method to form a fine particle layer having a size of 5 mm × 5 mm and a thickness of 200 μm. Thereafter, the TiO ₂ fine particles were sintered on the FTO layer by holding at 500 ° C. for 30 minutes. A 0.1 M titanium chloride (IV) TiCl ₄ aqueous solution was added dropwise to the sintered TiO ₂ film, kept at room temperature for 15 hours, washed, and fired again at 500 ° C. for 30 minutes. Thereafter, the ultraviolet light irradiation apparatus is used to irradiate the TiO ₂ sintered body with ultraviolet light for 30 minutes, and impurities such as organic substances contained in the TiO ₂ sintered body are oxidatively decomposed and removed by the photocatalytic action of TiO _2. The porous electrode 3 was obtained by performing a treatment for increasing the activity of the TiO ₂ sintered body.

  As a photosensitizing dye, 23.8 mg of fully purified Z907 was dissolved in 50 ml of a mixed solvent in which acetonitrile and tert-butanol were mixed at a volume ratio of 1: 1 to prepare a photosensitizing dye solution.

The photosensitizing dye solution thus prepared was soaked into a nonwoven fabric having the same planar shape as the porous electrode 3. Then, the nonwoven fabric containing the photosensitizing dye solution is pressed against the porous electrode 3 at room temperature, and the photosensitizing dye solution is supplied from the nonwoven fabric to the porous electrode 3, and the photosensitizing dye is applied to the surface of the TiO ₂ fine particles. Was adsorbed. Next, the porous electrode 3 was washed sequentially with an acetonitrile solution of 4-tert-butylpyridine and acetonitrile, and then the solvent was evaporated in the dark and dried.

  The counter electrode 6 is formed by sequentially depositing a 50 nm-thick chromium layer and a 100 nm-thick platinum layer on a FTO layer, in which a liquid injection port having a diameter of 0.5 mm is formed in advance, by sputtering. An isopropyl alcohol (2-propanol) solution was spray coated and formed by heating at 385 ° C. for 15 minutes.

  Next, the transparent substrate 1 and the counter substrate 4 were disposed so that the porous electrode 3 and the counter electrode 6 face each other, and the outer periphery was sealed with an ionomer resin film and an acrylic ultraviolet curable resin.

Meanwhile, 2.0 g of 3-methoxypropionitrile (MPN) as a solvent, 0.030 g of sodium iodide NaI, 1.0 g of 1-propyl-2,3-dimethylimidazolium iodide, 0.10 g of iodine I ₂ In addition to 0.054 g of 2-NH2-Py as an additive, quinuclidine (Q) was dissolved to prepare an electrolytic solution.

  This electrolytic solution was injected from a liquid injection port of a dye-sensitized photoelectric conversion element prepared in advance using a liquid feed pump, and the pressure inside the element was reduced to expel bubbles inside the element. Thus, the electrolyte layer 7 is formed. Next, the liquid inlet was sealed with an ionomer resin film, an acrylic resin, and a glass substrate to complete a dye-sensitized photoelectric conversion element.

  As described above, according to the second embodiment, in addition to the same advantages as those of the first embodiment, the following advantages can be obtained. That is, the holding material 9 holding the photosensitizing dye solution is pressed against the porous electrode 3 to supply the internal photosensitizing dye solution from the holding material 9 to the porous electrode 3, thereby photosensitizing. The dye is adsorbed on the porous electrode 3. For this reason, the photosensitizing dye can be adsorbed to the porous electrode 3 very easily, and the manufacturing cost of the dye-sensitized photoelectric conversion element can be reduced. Moreover, since the minimum amount of the photosensitizing dye solution is sufficient, the amount of the photosensitizing dye solution to be used can be greatly reduced. Further, in the conventional method of adsorbing the photosensitizing dye by immersing the porous electrode 3 in the photosensitizing dye solution, there is a possibility that the photosensitizing dye solution is contaminated or the composition is changed. On the other hand, according to the first embodiment, each time the pressing is performed by the holding material 9, a photosensitizing dye solution having no contamination and fresh and having a constant composition can be supplied. There are no problems due to contamination or composition changes. As a result, a dye-sensitized photoelectric conversion element having excellent photoelectric conversion characteristics can be produced at low cost.

<3. Third Embodiment>
[Method for producing dye-sensitized photoelectric conversion element]
As described above, in the second embodiment, the porous electrode 3 has substantially the same planar shape, and the porous electrode 3 is pressed once by the holding material 9 that holds the photosensitizing dye solution. A photosensitizing dye solution is supplied to the entire surface, and the photosensitizing dye is adsorbed to the entire porous electrode 3. In contrast, in the second embodiment, the holding material 9 having a smaller cross-sectional area than the area of the porous electrode 3 is used, and the holding material 9 is porous several times while changing the location on the porous electrode 3. By pressing against the porous electrode 3, the photosensitizing dye is finally adsorbed to the entire porous electrode 3.

  That is, in the third embodiment, as shown in FIG. 7A, the holding material 9 having a cross-sectional area smaller than the area of the porous electrode 3 is positioned above a portion close to the end of the porous electrode 3. The shape of the cross section of the holding member 9 is selected as necessary, and may be various shapes, such as a rectangle or a square.

  Next, as shown in FIG. 7B, the holding material 9 is lowered and pressed against the porous electrode 3, and the photosensitizing dye solution held therein is supplied from the holding material 9 to the porous electrode 3.

  Next, as shown in FIG. 7C, the holding material 9 is raised once and then moved in the horizontal direction to be positioned above the area adjacent to the first pressing area by the holding material 9, and then lowered to make the porous material porous. The photosensitizing dye solution held inside is pressed from the holding material 9 and supplied to the porous electrode 3.

  Next, as shown in FIG. 7D, the holding material 9 is raised once and then moved in the horizontal direction, positioned above the area adjacent to the second pressing area by the holding material 9, and then lowered to make it porous. The photosensitizing dye solution held inside is pressed from the holding material 9 and supplied to the porous electrode 3.

  If necessary, the same operation as above is repeated to supply the photosensitizing dye solution to the entire surface of the porous electrode 3. Thereby, the photosensitizing dye can be adsorbed to the entire porous electrode 3.

Except for the above, the third embodiment is the same as the second embodiment.
According to the third embodiment, advantages similar to those of the second embodiment can be obtained.

<4. Fourth Embodiment>
[Method for producing dye-sensitized photoelectric conversion element]
In the fourth embodiment, a case where a multicolor dye-sensitized photoelectric conversion element is manufactured will be described.

  8A to 8C show a photosensitizing dye adsorption process to the porous electrode 3 in the fourth embodiment.

  In the fourth embodiment, as shown in FIG. 8A, a plurality of holding materials (here, having a cross-sectional area substantially equal to an area obtained by dividing the upper surface of the porous electrode 3 into a plurality of regions each having a predetermined planar shape) Then, for example, two holding members 9a and 9b) are prepared and arranged adjacent to each other on the same surface. A plurality of types (for example, two types) of photosensitizing dye solutions in which a plurality of types of photosensitizing dyes having different light absorption properties are dissolved are prepared, and these photosensitizing dye solutions are used as the respective holding materials 9a, 9b. In FIG. 8A, the two types of photosensitizing dyes contained in the two types of photosensitizing dye solutions are schematically shown by stippling having different sizes from each other (hereinafter, the two types of photosensitizing dyes are also schematically illustrated. Are shown in stipples of different sizes).

Next, as shown in FIG. 8B, these holding materials 9a and 9b are simultaneously lowered and pressed against the porous electrode 3, and the respective photosensitizing dyes held in the inside from these holding materials 9a and 9b. The solution is supplied to the porous electrode 3. As a result, the photosensitizing dye from the photosensitizing dye solution held on the holding material 9a is adsorbed to the region on one side of the porous electrode 3, and the holding material 9b is held on the other side region. The photosensitizing dye from the photosensitizing dye solution is adsorbed.
Thereafter, as shown in FIG. 8C, the holding members 9a and 9b are raised.

  Here, the case where two holding materials 9a and 9b holding different photosensitizing dye solutions are used has been described. However, the present invention is not limited to this. The number of holding materials, the front end surface of the holding material (for pressing) The shape of the surface used), the pressing position by the holding material, and the like are appropriately selected according to the pattern (image) to be displayed in multiple colors by the dye-sensitized photoelectric conversion element. In addition, the photosensitizing dye solution to be held on the plurality of holding materials is appropriately selected according to the pattern to be displayed in multiple colors by the dye-sensitized photoelectric conversion element. Two or more holding materials out of the plurality of holding materials may hold the same photosensitizing dye solution.

Except for the above, the fourth embodiment is the same as the second embodiment.
According to the fourth embodiment, in addition to the same advantages as those of the second embodiment, the following advantages can be obtained. That is, by selecting a photosensitizing dye to be adsorbed in a plurality of different regions of the porous electrode 3, a dye-sensitized photoelectric conversion element that exhibits an appearance such as a multicolor pattern in which these regions are different from each other is manufactured. Can be easily manufactured without complication. In addition, each of the photosensitizing dye solutions can be selectively selected by simply pressing a plurality of holding materials (for example, holding materials 9a and 9b) respectively holding the different photosensitizing dye solutions against the respective portions on the upper surface of the porous electrode 3. Therefore, each photosensitizing dye can be adsorbed to each region while suppressing bleeding. For this reason, the boundary between the several area | region which the photosensitizing dye from which a mutually different kind of the porous electrode 3 adsorb | sucks can be made clear, and the area | region color-coded in multiple colors can be formed with a clear boundary. In addition, a dye-sensitized photoelectric conversion element having high image quality and easy contrast control can be easily realized.

<5. Fifth Embodiment>
[Method for producing dye-sensitized photoelectric conversion element]
In the fifth embodiment, a case where a multicolor dye-sensitized photoelectric conversion element is manufactured will be described.

  9A to 9C show a photosensitizing dye adsorption step on the porous electrode 3 in the fifth embodiment.

  In the fifth embodiment, as shown in FIG. 9A, a plurality of holding materials (here, two holding materials 9a) having a cross-sectional area substantially equal to the area obtained by dividing the upper surface of the porous electrode 3 into a plurality of regions. 9b) are arranged adjacent to each other on the same plane. A plurality of types of photosensitizing dye solutions in which a plurality of types of photosensitizing dyes having different light absorption properties are dissolved are prepared, and these photosensitizing dye solutions are held in the holding materials 9a and 9b, respectively.

  Next, as shown in FIG. 9B, for example, the holding material 9 a is first lowered and pressed against the porous electrode 3, and the photosensitizing dye solution held inside the holding material 9 a is applied to the porous electrode 3. Supply. As a result, the photosensitizing dye from the photosensitizing dye solution held on the holding material 9a is adsorbed to the region on one side of the porous electrode 3. Thereafter, the holding material 9a is raised.

  Next, as shown in FIG. 9C, the holding material 9 b is lowered and pressed against the porous electrode 3, and the photosensitizing dye solution held therein is supplied from the holding material 9 b to the porous electrode 3. As a result, the photosensitizing dye from the photosensitizing dye solution held by the holding material 9b is adsorbed to the other one side region of the porous electrode 3. Thereafter, the holding material 9b is raised.

  Here, the case where two holding materials 9a and 9b holding different photosensitizing dye solutions are used has been described. However, the present invention is not limited to this, and the number of holding materials is selected as necessary. In addition, different photosensitizing dye solutions may be held on the plurality of holding materials, respectively, or two or more holding materials of the plurality of holding materials hold the same photosensitizing dye solution. You may make it do.

Except for the above, the fifth embodiment is the same as the second embodiment.
According to the fifth embodiment, in addition to the same advantages as those of the second embodiment, the same advantages as those of the fourth embodiment can be obtained.

<6. Sixth Embodiment>
[Method for producing dye-sensitized photoelectric conversion element]
In the sixth embodiment, a method of selectively desorbing the photosensitizing dye from the porous electrode 3 for some purpose after the photosensitizing dye is adsorbed on the porous electrode 3 will be described.
FIGS. 10A to 10C show a desorption process of the photosensitizing dye from the porous electrode 3.

  As shown in FIG. 10A, a holding material 10 for holding a photosensitizing dye removing solution, for example, an alkaline solution, is positioned above the porous electrode 3 on which the photosensitizing dye is adsorbed as a whole.

  Next, as shown in FIG. 10B, the holding material 10 is lowered to selectively press the porous electrode 3, and the photosensitizing dye detachment solution held in the inside from the holding material 10 is removed. Supply to the porous electrode 3. As a result, the photosensitizing dye detachment solution penetrates into the porous electrode 3 from the pressed region by the holding material 10, and the photosensitizing dye in this portion is selectively detached as shown in FIG. 10C. .

Except for the above, the sixth embodiment is the same as the first embodiment.
According to the sixth embodiment, in addition to the same advantages as those of the second embodiment, the advantage that the photosensitizing dye can be easily detached from a desired region of the porous electrode 3 is obtained. Can be obtained.

<7. Seventh Embodiment>
[Method for producing dye-sensitized photoelectric conversion element]
In the seventh embodiment, in the method for manufacturing the dye-sensitized photoelectric conversion element according to the second embodiment, the surface of the transparent electrode 2 formed on the transparent substrate 1 is treated with an aqueous TiCl ₄ solution (steps). A), then, the step of washing the surface of the transparent electrode 2 with water and ethanol (Step B), the step of forming the porous electrode 3 by firing, and then treating the surface of the porous electrode 3 with an aqueous TiCl ₄ solution ( Step C), then, the step of washing the surface of the porous electrode 3 with water or ethanol (Step D), after the photosensitizing dye is adsorbed on the porous electrode 3, the porous electrode 3 is washed with a cleaning solution such as acetonitrile. One or two or more of the step (step E) of washing by the step (step E) and the step of impregnating the porous electrode 3 with the electrolytic solution (step F) are performed by pressing with a holding material that holds the solution To do.

In step A, as shown in FIG. 11A, the holding material 11 holding the TiCl ₄ aqueous solution is pressed against the surface of the transparent electrode 2, and the TiCl ₄ aqueous solution is supplied from the holding material 11 to the surface of the transparent electrode 2. The surface of the transparent electrode 2 is treated with an aqueous TiCl ₄ solution. If necessary, the surface of the transparent electrode 2 may be partially treated by making the cross-sectional area of the holding material 11 smaller than the area of the transparent electrode 2, or transparent by multiple pressings by the holding material 11. The entire surface of the electrode 2 may be processed.

  In step B, as shown in FIG. 11B, for example, the holding material 12 holding water or ethanol is pressed against the surface of the transparent electrode 2 to supply water or ethanol from the holding material 12 to the surface of the transparent electrode 2. The surface of the transparent electrode 2 is washed with this water or ethanol. If necessary, the surface of the transparent electrode 2 may be partially cleaned by making the cross-sectional area of the holding material 12 smaller than the area of the transparent electrode 2, or transparent by multiple pressings by the holding material 12. The entire surface of the electrode 2 may be cleaned.

In step C, as shown in FIG. 11C, the holding material 13 holding the TiCl ₄ aqueous solution is pressed against the surface of the porous electrode 3, and the TiCl ₄ aqueous solution is supplied from the holding material 13 to the surface of the porous electrode 3. The surface of the porous electrode 3 is treated with this TiCl ₄ aqueous solution. If necessary, the surface of the porous electrode 3 may be partially processed by reducing the cross-sectional area of the holding material 13 to be smaller than the area of the porous electrode 3, or a plurality of times of pressing by the holding material 13 Thus, the entire surface of the porous electrode 3 may be treated.

  In step D, as shown in FIG. 12A, for example, a holding material 14 holding water or ethanol is pressed against the surface of the porous electrode 3, and water or ethanol is supplied from the holding material 14 to the surface of the porous electrode 3. The surface of the porous electrode 3 is washed with water or ethanol. If necessary, the surface of the porous electrode 3 may be partially cleaned by making the cross-sectional area of the holding material 14 smaller than the area of the porous electrode 3, or may be pressed multiple times by the holding material 14. Thus, the entire surface of the porous electrode 3 may be washed.

  In the step E, as shown in FIG. 12B, for example, the holding material 15 holding acetonitrile is pressed against the surface of the porous electrode 20, and acetonitrile is supplied from the holding material 15 to the surface of the porous electrode 3, The surface of the porous electrode 3 is washed. If necessary, the surface of the porous electrode 3 may be partially cleaned by making the cross-sectional area of the holding material 15 smaller than the area of the porous electrode 3, or may be pressed several times by the holding material 15. Thus, the entire surface of the porous electrode 3 may be washed.

  In step F, as shown in FIG. 12C, the holding material 16 holding the electrolytic solution is pressed against the surface of the porous electrode 3, and the electrolytic solution is supplied from the holding material 16 to the surface of the porous electrode 3. The porous electrode 3 is impregnated with an electrolytic solution. If necessary, the porous electrode 3 may be partially impregnated with the electrolytic solution by making the cross-sectional area of the holding material 16 smaller than the area of the porous electrode 3, or a plurality of times by the holding material 16. The whole porous electrode 3 may be impregnated with an electrolytic solution by pressing.

Except for the above, the seventh embodiment is the same as the second embodiment.
According to the seventh embodiment, in addition to the same advantages as those of the second embodiment, there is an advantage that the surface and the cleaning of the transparent electrode 2 and the porous electrode 3 can be easily performed. be able to.

<8. Eighth Embodiment>
[Method for producing dye-sensitized photoelectric conversion element]
In the eighth embodiment, in the method of manufacturing the dye-sensitized photoelectric conversion element according to the second embodiment, the electrolyte solution is injected by pressing with a holding material that holds the electrolyte solution.
13A to 13C show the injection process of this electrolytic solution.

  As shown in FIG. 13A, the porous electrode 3 is formed on the transparent electrode 2 on the transparent substrate 1, the sealing material 8 is applied to the outer peripheral portion of the transparent electrode 2, and then electrolysis is performed above the porous electrode 3. The holding material 17 that holds the liquid is positioned.

Next, as shown in FIG. 13B, the holding material 17 holding the electrolytic solution is pressed against the surface of the porous electrode 3, and the electrolytic solution is supplied from the holding material 17 to the surface of the porous electrode 3. An electrolytic solution 18 is attached on the electrode 3.
Next, as shown in FIG. 13C, the holding material 13 is raised.
Thereafter, the counter electrode 6 is bonded to the sealing material 8 to manufacture a dye-sensitized photoelectric conversion element.

Except for the above, the eighth embodiment is the same as the second embodiment.
According to the eighth embodiment, in addition to the same advantages as those of the second embodiment, the following advantages can be obtained. That is, when the electrolytic solution is injected using a conventional ODF, the porous electrode 3 is formed on the transparent electrode 2 on the transparent substrate 1 and the sealing material 8 is applied to the outer peripheral portion of the transparent electrode 2. The electrolytic solution is supplied from above the porous electrode 3 by ODF. However, in this method, since the uncured sealing material 8 is present in the vicinity of the electrolytic solution, when the electrolytic solution contacts the uncured sealing material 8, defective curing or leakage of the electrolytic solution is caused. In order to cause this, it is necessary to control the injection conditions, which is complicated. On the other hand, according to the seventh embodiment, the electrolytic solution 18 is adhered onto the porous electrode 3 by pressing the holding material 17 that holds the electrolytic solution against the porous electrode 3, so that a desired portion is obtained. The electrolyte solution 18 can be injected accurately.

<9. Ninth Embodiment>
[Method for producing dye-sensitized photoelectric conversion element]
Attempts have been made to produce dye-sensitized photoelectric conversion elements by a roll-to-roll process. In the ninth embodiment, when a dye-sensitized photoelectric conversion element is manufactured by a roll-to-roll process, various processes using a liquid are performed by pressing a holding material that holds the liquid. Will be described.

  FIG. 14 shows a method of supplying a desired amount of liquid to a desired site by a stamping process. As shown in FIG. 14, a manufacturing apparatus configured so that a film electrode 19 in which an electrode is formed on a transparent base film can be fed by rollers 20 and 21 is used. The film electrode 19 between the rollers 20 and 21 is typically horizontal. A stamp 22 is positioned above the horizontal film electrode 19. This stamp 22 is provided with a cylindrical container 24 on a holding material 23 containing a solution at the bottom, and the container 24 contains a liquid 25 and serves as a liquid reservoir. The liquid 25 in the container 24 is always permeated into the holding material 24, and the liquid 24 is held.

In the method of manufacturing the dye-sensitized photoelectric conversion element, after the feeding of the film-like electrode 19 is stopped, the stamp 22 is lowered and the lower holding material 23 is pressed against the film-like electrode 19 from the holding material 24. The liquid is supplied to the film electrode 19. Specifically, for example, when the film-like electrode 19 corresponds to the dye-sensitized photoelectric conversion element shown in FIG. 1 in which the transparent electrode 2 is formed on the transparent substrate 1, TiCl is used as the holding material 24. ₄ is held, the holding material 24 is pressed against the film-like electrode 19, and TiCl ₄ is supplied to the film-like electrode 19 to treat the surface thereof. Alternatively, when the film-like electrode 19 corresponds to the dye-sensitized photoelectric conversion element shown in FIG. 1 in which the transparent electrode 2 and the porous electrode 3 are formed on the transparent substrate 1, light is applied to the holding material 24. The sensitizing dye solution is held, the holding material 24 is pressed against the film electrode 19, and the photosensitizing dye solution is supplied to the film electrode 19 to adsorb the photosensitizing dye.

  According to the ninth embodiment, in addition to the same advantages as those of the second embodiment, various types of liquids can be used when a dye-sensitized photoelectric conversion element is manufactured by a roll-to-roll process. The process can be easily performed by pressing with the holding material 24, and the advantage that the manufacturing cost of the dye-sensitized photoelectric conversion element can be significantly reduced can be obtained.

<10. Tenth Embodiment>
[Method for producing dye-sensitized photoelectric conversion element]
In the tenth embodiment, when a dye-sensitized photoelectric conversion element is manufactured by a roll-to-roll process, various processes using a liquid are performed by pressing a holding material that holds the liquid. Will be described.

FIG. 15 shows a method of supplying a desired amount of liquid to a desired site by a roll press process. As shown in FIG. 15, a tape-shaped holding material 27 is wound around the roller 26. A container 28 is provided above the roller 26, and a liquid 29 is contained in the container 28 to form a liquid reservoir. A liquid 29 is supplied from the container 28 to the holding material 27, and the liquid 29 is held in the holding material 27. Then, the film-like electrode 30 is sandwiched between the roller 26 and the roller 31 around which the holding material 27 is wound, thereby pressing the holding material 27 against the film-like electrode 30 to draw the liquid 29 from the holding material 27 into the film-like electrode. 30. Specifically, for example, when the film-like electrode 30 corresponds to the dye-sensitized photoelectric conversion element shown in FIG. 1 in which the transparent electrode 2 is formed on the transparent substrate 1, TiCl is used as the holding material 27. ₄ is held, the holding material 27 is pressed against the film electrode 30, and TiCl ₄ is supplied to the film electrode 30 to treat the surface. Alternatively, when the film-like electrode 30 corresponds to the dye-sensitized photoelectric conversion element shown in FIG. 1 in which the transparent electrode 2 and the porous electrode 3 are formed on the transparent substrate 1, light is applied to the holding material 27. The sensitizing dye solution is held, and the holding material 27 is pressed against the film electrode 30 to supply the photosensitizing dye solution to the film electrode 30 to adsorb the photosensitizing dye.
According to the tenth embodiment, the same advantages as those of the ninth embodiment can be obtained.

<11. Eleventh Embodiment>
[Dye-sensitized photoelectric conversion element]
In this dye-sensitized photoelectric conversion element, in addition to the first additive, at least one of the above-described various second additives is added to the electrolytic solution constituting the electrolyte layer 7. The composition of the second additive is selected as necessary, and is, for example, 0.01 M or more and 1 M or less, typically 0.05 M or more and 0.5 M or less.

[Method for producing dye-sensitized photoelectric conversion element]
In this method of manufacturing a dye-sensitized photoelectric conversion element, in addition to the first additive, at least one of the above-described various second additives is added to the electrolytic solution constituting the electrolyte layer 7. Except for this, it is the same as in the first embodiment.

<Example 4>
In Example 4, 0.10 g of iodine I ₂ and 1.0 M of N-butylbenzimid as an additive were added to 1.0 M 1-propyl-3-methylimidazolium iodide (MPImI) / EMImTCB as a solvent. Dazole (NBB), quinuclidine (Q) as the first additive, and 0.1 M GuOTf as the second additive were dissolved to prepare an electrolyte solution. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Example 1.

<Example 5>
A dye-sensitized photoelectric conversion element was produced in the same manner as in Example 4 except that EMImSCN was used as the second additive to be added to the electrolytic solution.

<Example 6>
A dye-sensitized photoelectric conversion element was produced in the same manner as in Example 4 except that EMImOTf was used as the second additive to be added to the electrolytic solution.

<Example 7>
A dye-sensitized photoelectric conversion element was produced in the same manner as in Example 4 except that EMImTFSI was used as the second additive to be added to the electrolytic solution.

<Example 8>
A dye-sensitized photoelectric conversion element was produced in the same manner as in Example 4 except that EMImTfAc was used as the second additive to be added to the electrolytic solution.

<Example 9>
A dye-sensitized photoelectric conversion element was produced in the same manner as in Example 4 except that EMImDINHOP was used as the second additive to be added to the electrolytic solution.

<Example 10>
A dye-sensitized photoelectric conversion element was produced in the same manner as in Example 4 except that EMIMMeSO ₃ was used as the second additive to be added to the electrolytic solution.

光増感色素溶液は、十分に精製したＺ９９１ ２３．８ｍｇを、アセトニトリルとｔｅｒｔ−ブタノールとを１：１の体積比で混合した混合溶媒５０ｍｌに溶解させることにより調製した。また、電解液に添加する第１の添加剤としてＥＭＩｍＳＣＮを用いた。その他は実施例４と同様にして色素増感光電変換素子を製造した。 <Example 11>
Z991 represented by the following structural formula was used as a photosensitizing dye.

The photosensitizing dye solution was prepared by dissolving 23.8 mg of fully purified Z991 in 50 ml of a mixed solvent in which acetonitrile and tert-butanol were mixed at a volume ratio of 1: 1. Moreover, EMImSCN was used as the first additive to be added to the electrolytic solution. Others were carried out similarly to Example 4, and manufactured the dye-sensitized photoelectric conversion element.

<Example 12>
A dye-sensitized photoelectric conversion element was produced in the same manner as in Example 11 except that EMImDCA was used as the second additive to be added to the electrolytic solution.

<Example 13>
A dye-sensitized photoelectric conversion element was produced in the same manner as in Example 11 except that EMImBF ₄ was used as the second additive to be added to the electrolytic solution.

<Example 14>
A dye-sensitized photoelectric conversion element was produced in the same manner as in Example 11 except that EMImPF ₆ was used as the second additive to be added to the electrolytic solution.

<Example 15>
A dye-sensitized photoelectric conversion element was produced in the same manner as in Example 11 except that EMImFAP was used as the second additive to be added to the electrolytic solution.

<Example 16>
A dye-sensitized photoelectric conversion element was produced in the same manner as in Example 11 except that EMImTFSI was used as the second additive to be added to the electrolytic solution.

<Example 17>
A dye-sensitized photoelectric conversion element was produced in the same manner as in Example 11 except that EMImOTf was used as the second additive to be added to the electrolytic solution.

<Example 18>
A dye-sensitized photoelectric conversion element was produced in the same manner as in Example 11 except that EMImTfAc was used as the second additive to be added to the electrolytic solution.

<Example 19>
A dye-sensitized photoelectric conversion element was produced in the same manner as in Example 11 except that EMIMMeSO ₃ was used as the second additive to be added to the electrolytic solution.

<Example 20>
A dye-sensitized photoelectric conversion element was produced in the same manner as in Example 11 except that EMImEt ₂ PO ₄ was used as the second additive to be added to the electrolytic solution.

<Example 21>
A dye-sensitized photoelectric conversion element was produced in the same manner as in Example 11 except that EMImCB ₁₁ H ₁₂ was used as the second additive to be added to the electrolytic solution.

<Comparative example 1>
A dye-sensitized photoelectric conversion element was produced in the same manner as in Example 4 except that GuSCN was used as the second additive to be added to the electrolytic solution.

<Comparative example 2>
A dye-sensitized photoelectric conversion element was produced in the same manner as in Example 11 except that GuSCN was used as the second additive to be added to the electrolytic solution.

  In order to clearly verify the effect of adding the second additive to the electrolytic solution, in the manufacturing steps of the dye-sensitized photoelectric conversion elements of Examples 4 to 21 and Comparative Examples 1 and 2, the first electrolyte was added to the electrolytic solution. A dye-sensitized photoelectric conversion element was produced using an electrolytic solution to which no additive was added. The dye-sensitized photoelectric conversion elements thus produced are referred to as Reference Examples 1 to 18 and Reference Comparative Examples 1 and 2, corresponding to Examples 4 to 21 and Comparative Examples 1 and 2. A test was conducted to examine the durability of the dye-sensitized photoelectric conversion elements of Reference Examples 1 to 18 and Reference Comparative Examples 1 and 2. The durability test was performed by holding the dye-sensitized photoelectric conversion element at 85 ° C. in a dark place and measuring a change with time in photoelectric conversion efficiency. Maintenance rate (%) of photoelectric conversion efficiency after 150 hours and after 1000 hours when the initial photoelectric conversion efficiency of the dye-sensitized photoelectric conversion elements of Reference Examples 1 to 7 and Reference Comparative Example 1 is 100 (%) Table 4 shows the measurement results. In Table 4, the photoelectric conversion efficiency after 150 hours of the dye-sensitized photoelectric conversion elements of Reference Examples 1 to 7 was normalized by the photoelectric conversion efficiency after 150 hours of the dye-sensitized photoelectric conversion elements of Reference Comparative Example 1. (The photoelectric conversion efficiency after 150 hours of the dye-sensitized photoelectric conversion element of Reference Comparative Example 1 was taken as 100). Moreover, the measurement result of the maintenance rate (%) of the photoelectric conversion efficiency after progress for 150 hours when the initial photoelectric conversion efficiency of the dye-sensitized photoelectric conversion elements of Reference Examples 8 to 18 and Reference Comparative Example 2 is 100 (%) Is shown in Table 5. Table 5 standardizes the photoelectric conversion efficiency after 150 hours of the dye-sensitized photoelectric conversion elements of Reference Examples 8 to 18 by the photoelectric conversion efficiency after 150 hours of the dye-sensitized photoelectric conversion elements of Reference Comparative Example 2. (The photoelectric conversion efficiency after 150 hours of the dye-sensitized photoelectric conversion element of Reference Comparative Example 2 was taken as 100).

From Table 4, the maintenance rate of the photoelectric conversion efficiency of the dye-sensitized photoelectric conversion elements of Reference Examples 1 to 7 is higher than the maintenance rate of the photoelectric conversion efficiency of the dye-sensitized photoelectric conversion element of Reference Comparative Example 1. . Further, from Table 5, the maintenance rate of the photoelectric conversion efficiency of the dye-sensitized photoelectric conversion elements of Reference Examples 8 to 18 is higher than the maintenance ratio of the photoelectric conversion efficiency of the dye-sensitized photoelectric conversion element of Reference Comparative Example 2. ing. These results, as a second additive to the electrolyte, GuOTf, EMImSCN, EMImOTf, EMImTFSI , EMImTfAc, EMImDINHOP, EMImMeSO 3, EMImDCA, EMImBF 4, EMImPF 6, EMImFAP, the EMImEt ₂ PO ₄ or EMImCB ₁₁ H ₁₂ It can be seen that the addition rate can improve the photoelectric conversion efficiency maintenance rate.

  According to the eleventh embodiment, in addition to the same advantages as the first embodiment, the following advantages can be obtained. That is, since the first additive as described above is added to the electrolytic solution constituting the electrolyte layer 7 of the dye-sensitized photoelectric conversion element, the conventional dye-sensitized photoelectric using GuSCN as the additive of the electrolytic solution. Compared with the conversion element, the maintenance rate of the photoelectric conversion efficiency can be improved. For this reason, the durability of the dye-sensitized photoelectric conversion element can be improved. By using this excellent dye-sensitized photoelectric conversion element, a high-performance electronic device or the like can be realized.

<12. Twelfth Embodiment>
[Dye-sensitized photoelectric conversion element]
In this dye-sensitized photoelectric conversion element, the electrolyte layer 7 is formed of a porous film containing an electrolytic solution or impregnated with the electrolytic solution. As the porous film constituting the electrolyte layer 7, for example, various nonwoven fabrics made of an organic polymer compound are used. Although the specific example of the nonwoven fabric used for Table 6 as a porous membrane is given, it is not limited to this.

[Method for producing dye-sensitized photoelectric conversion element]
A method for producing the dye-sensitized photoelectric conversion element will be described.
First, the transparent electrode 2 is formed by forming a transparent conductive layer on one main surface of the transparent substrate 1 by sputtering or the like.

Next, as shown in FIG. 16A, the porous electrode 3 is formed on the transparent electrode 2 of the transparent substrate 1.
Next, a photosensitizing dye is bonded to the porous electrode 3 in the same manner as in the first embodiment.

Thereafter, similarly to the first embodiment, the conductive layer 5 is formed on the entire surface of the counter substrate 4, and the counter electrode 6 is formed thereon.
Next, as shown in FIG. 16B, an electrolyte layer 7 made of a porous film containing an electrolytic solution is placed on the porous electrode 3 on the transparent substrate 1.

Next, as shown in FIG. 16C, the counter substrate 4 is placed on the electrolyte layer 7 with the counter electrode 6 facing down, and then a sealing material 8 is formed on the outer peripheral portions of the transparent substrate 1 and the counter substrate 4 to form an electrolyte. Layer 7 is encapsulated. If necessary, after the counter substrate 4 is installed on the electrolyte layer 7, the counter substrate 4 may be pressed against the electrolyte layer 7 to compress the electrolyte layer 7 in a direction perpendicular to the surface. By doing in this way, when the thickness of the porous film constituting the electrolyte layer 7 is reduced by compression, the electrolyte contained in the void portion of the porous film is pushed out and the electrolyte becomes porous electrode 3. Therefore, the electrolytic solution can easily spread over the entire porous electrode 3. The final thickness of the electrolyte layer 7 is, for example, 1 to 100 μm, preferably 1 to 50 μm.
Thus, the target dye-sensitized photoelectric conversion element is manufactured.

<Example 22>
A dye-sensitized photoelectric conversion element was produced as follows.
The porous electrode 3 is formed in the same manner as in Example 1.

  As a photosensitizing dye, 23.8 mg of fully purified Z991 was dissolved in 50 ml of a mixed solvent in which acetonitrile and tert-butanol were mixed at a volume ratio of 1: 1 to prepare a photosensitizing dye solution.

Next, the photosensitizing dye was adsorbed on the porous electrode 3 in the same manner as in Example 1.
On the other hand, to 3-methoxypropionitrile (MPN) as a solvent, 1.0 M 1-propyl-3-methylimidazolium iodide (MPImI), 0.1 M iodine I ₂ , and 0.3 M as an additive Of N-butylbenzmidazole (NBB) was dissolved to prepare an electrolytic solution. A porous film made of polyolefin having a porosity of 71.4% and a film thickness of 31.2 μm was impregnated with this electrolytic solution.

Next, on the porous electrode 3 on the transparent substrate 1, a porous film made of polyolefin previously impregnated with an electrolytic solution as described above was installed to form an electrolyte layer 7.
Next, this porous membrane is compressed in a direction perpendicular to the membrane surface by pressing. The actual porosity of the compressed porous membrane was 50%.

  Next, an ionomer resin film and an acrylic ultraviolet curable resin were provided as a sealing material on the outer periphery of the electrolyte layer 7.

  The counter electrode 6 is formed by sequentially depositing a 50 nm-thick chromium layer and a 100 nm-thick platinum layer on a FTO layer, in which a liquid injection port having a diameter of 0.5 mm is formed in advance, by sputtering. An isopropyl alcohol (2-propanol) solution was spray coated and formed by heating at 385 ° C. for 15 minutes.

  The counter electrode 6 thus formed was placed on the electrolyte layer 7 and adhered to a sealing material provided on the outer periphery of the electrolyte layer 7 to complete a dye-sensitized photoelectric conversion element.

<Example 23>
The electrolyte layer 7 was formed using a porous membrane made of polyolefin having a porosity of 70.7% and a film thickness of 30 μm as the porous membrane impregnated with the electrolytic solution. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Example 22.

<Example 24>
The electrolyte layer 7 was formed using a porous membrane made of polyolefin having a porosity of 70.5% and a film thickness of 44 μm as the porous membrane impregnated with the electrolytic solution. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Example 22.

<Example 25>
The electrolyte layer 7 was formed using a porous film made of polyester having a porosity of 79% and a film thickness of 28 μm as the porous film impregnated with the electrolytic solution. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Example 22.

<Example 26>
The electrolyte layer 7 was formed using a porous film made of cellulose having a porosity of 72.8% and a film thickness of 29.8 μm as the porous film impregnated with the electrolytic solution. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Example 22.

<Example 27>
The electrolyte layer 7 was formed using a porous film made of polyester having a porosity of 78.3% and a film thickness of 32 μm as the porous film impregnated with the electrolytic solution. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Example 22.

<Example 28>
The electrolyte layer 7 was formed using a porous film made of polyester having a porosity of 82.7% and a film thickness of 22 μm as the porous film impregnated with the electrolytic solution. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Example 22.

<Comparative Example 3>
An electrolyte layer 7 made only of an electrolyte solution was formed without using a porous membrane. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Example 22.

  Table 6 summarizes the material, porosity, film thickness, and actual porosity of the porous film used for forming the electrolyte layer 7 in the dye-sensitized photoelectric conversion elements of Examples 22 to 28. Here, the actual porosity of the porous membrane is expressed as follows.

Actual porosity (%) = 100 - (100 - porosity of the membrane (%)) × membrane volume (m ³⁾ / (volume of the electrolyte layer 7 (m ³⁾ - bulk volume (m ³ of the porous electrode 3 ))

In order to more clearly verify the effect of constituting the electrolyte layer 7 with a porous membrane containing an electrolyte solution or impregnated with the electrolyte solution, instead of the electrolyte solutions of Examples 22 to 28, 3-Methoxypropionitrile (MPN), 1.0 M 1-propyl-3-methylimidazolium iodide (MPImI), 0.1 M iodine I ₂ , and 0.3 M N-butylbenz as additive Dye sensitization in which photosensitizing dye is adsorbed on porous electrode 3 by immersing porous electrode 3 in a photosensitizing dye solution using an electrolyte prepared by dissolving midazole (NBB) A photoelectric conversion element was manufactured. These dye-sensitized photoelectric conversion elements are referred to as Reference Examples 19 to 25 corresponding to Examples 22 to 28. Moreover, the dye-sensitized photoelectric conversion element using the electrolyte layer 7 which consists only of electrolyte solution instead of the electrolyte layer 7 which consists of the porous film of Reference Examples 19-25 containing the electrolyte solution or impregnated with the electrolyte solution To Reference Comparative Example 3. The current-voltage characteristics of the dye-sensitized photoelectric conversion elements of Reference Examples 19 to 25 and Reference Comparative Example 3 were measured. The measurement was performed by irradiating the dye-sensitized photoelectric conversion element with artificial sunlight (AM1.5, 100 mW / cm ² ). Tables 7 and 8 show the measurement results of the photoelectric conversion efficiency (Eff) of these dye-sensitized photoelectric conversion elements.

  FIG. 17 shows the actual porosity of the porous film used for forming the electrolyte layer 7 in the dye-sensitized photoelectric conversion elements of Reference Examples 19 to 25 and the photoelectric conversion efficiency of the dye-sensitized photoelectric conversion elements of Reference Examples 19 to 25. Shows the relationship with the normalized photoelectric conversion efficiency normalized by the photoelectric conversion efficiency of the dye-sensitized photoelectric conversion element of Reference Comparative Example 3.

  From Table 7, Table 8, and FIG. 17, the photoelectric conversion efficiency of the dye-sensitized photoelectric conversion elements of Reference Examples 19 to 25 is generally slightly lower than the photoelectric conversion efficiency of the dye-sensitized photoelectric conversion element of Reference Comparative Example 3. . However, the photoelectric conversion efficiencies of the dye-sensitized photoelectric conversion elements of Reference Examples 19, 20, and 22 to 25 using a porous film having an actual porosity of 50% or more for forming the electrolyte layer 7 are the same as those of Reference Comparative Example 3. It is 80% or more of the photoelectric conversion efficiency of the sensitized photoelectric conversion element. The photoelectric conversion efficiency of the dye-sensitized photoelectric conversion elements of Reference Examples 19, 20, and 22 to 25 increases as the actual porosity of the porous film used for forming the electrolyte layer 7 increases, and the actual porosity is increased. If it is 80% or more and less than 100%, the value is comparable to the photoelectric conversion efficiency of the dye-sensitized photoelectric conversion element of Reference Comparative Example 3.

  FIG. 18 shows the dye of Reference Comparative Example 3 in which the electrolyte layer 7 was formed only from the dye-sensitized photoelectric conversion element of Reference Example 25 and the electrolytic solution in which a porous film having an actual porosity of 79% was used for forming the electrolyte layer 7. The measurement result of the IPCE spectrum of a sensitized photoelectric conversion element is shown. As shown in FIG. 18, it can be seen that the dye-sensitized photoelectric conversion element of Reference Example 25 has an increased photoelectric conversion efficiency in the entire wavelength region as compared with the dye-sensitized photoelectric conversion element of Reference Comparative Example 3. This is thought to be due to the following reasons. That is, as shown in FIG. 19A, in the dye-sensitized photoelectric conversion element of Reference Comparative Example 3, the light that has not been completely absorbed by the photosensitizing dye out of the light incident on the porous electrode 101 is composed only of the electrolytic solution. The electrolyte layer 102 is transmitted. On the other hand, as shown in FIG. 19B, in the dye-sensitized photoelectric conversion element of Reference Example 25, it was not completely absorbed by the photosensitizing dye out of the light incident on the porous electrode 3 and was incident on the electrolyte layer 7. The light is effectively scattered by the porous film forming the electrolyte layer 7 because the porous film has many voids. Thus, the light scattered by the electrolyte layer 7 enters the porous electrode 3 again from the back side and is absorbed by the photosensitizing dye. In this case, the scattered light from the porous film has a large amount of components incident obliquely to the surface of the porous electrode 3, so that the optical path length inside the porous electrode 3 is significantly increased. Incident light collection rate increases. As a result, in the dye-sensitized photoelectric conversion element of Reference Example 25, the photoelectric conversion efficiency increases in the entire wavelength region as compared with the dye-sensitized photoelectric conversion element of Reference Comparative Example 3.

  According to the twelfth embodiment, in addition to the same advantages as those of the first embodiment, the following advantages can be obtained. That is, since the electrolyte layer 7 of the dye-sensitized photoelectric conversion element is composed of a porous film containing an electrolytic solution, the electrolyte layer 7 is in a solid state and the electrolytic solution leaks when the photoelectric conversion element is damaged. It can be effectively prevented. Further, since the porous electrode 3 and the counter electrode 6 are separated by an insulating porous film, even if the dye-sensitized photoelectric conversion element is bent, the electrical insulation between the porous electrode 3 and the counter electrode 6 is lowered. Can be prevented. Also, unlike conventional dye-sensitized photoelectric conversion elements, it is not necessary to provide a liquid injection hole for injecting an electrolyte, wipe off the electrolyte after injecting the electrolyte, or close the liquid injection hole. The dye-sensitized photoelectric conversion element can be easily and easily manufactured. Further, since the electrolytic solution can be substantially handled as a membrane, the handling of the electrolytic solution becomes extremely simple. For this reason, for example, in the case of producing a dye-sensitized photoelectric conversion element on a transparent film by a roll-to-roll process, the electrolyte layer 7 made of a porous film containing an electrolytic solution is pasted on the transparent film as a film. Is possible. Further, in this dye-sensitized photoelectric conversion element, incident light that has not been absorbed by the photosensitizing dye adsorbed on the porous electrode 3 is scattered by the electrolyte layer 7 and is incident on the porous electrode 3 again. As a result, this dye-sensitized photoelectric conversion element can obtain a high photoelectric conversion efficiency comparable to that of a conventional dye-sensitized photoelectric conversion element in which the electrolyte layer 7 is composed only of an electrolytic solution. By using this excellent dye-sensitized photoelectric conversion element, a high-performance electronic device or the like can be realized.

<13. Thirteenth Embodiment>
[Method for producing dye-sensitized photoelectric conversion element]
20A to 20C show a method for manufacturing a dye-sensitized photoelectric conversion element according to the twelfth embodiment.
As shown in FIG. 20A, in the method of manufacturing the dye-sensitized photoelectric conversion element, first, the porous electrode 3 is formed in the same manner as in the first embodiment.

  On the other hand, as shown in FIG. 20A, an integrated film in which, for example, a thermosetting sealing material 8 is integrally formed with the electrolyte layer 7 on the outer periphery of the electrolyte layer 7 made of a porous film containing an electrolytic solution is prepared. The thickness of the electrolyte layer 7 in this state is larger than the final thickness of the electrolyte layer 7. The thickness of the sealing material 8 is larger than the thickness of the electrolyte layer 7, so that the sealing material 8 can finally be sufficiently sealed.

Next, as shown in FIG. 20B, an integral membrane in which a sealing material 8 is formed on the outer periphery of an electrolyte layer 7 made of a porous membrane containing an electrolytic solution is placed on the porous electrode 3.
Next, as shown in FIG. 20C, the counter electrode 6 provided on the counter substrate 4 is installed on the electrolyte layer 7 and the sealing material 8, and the counter substrate 4 is pressed against the electrolyte layer 7 so as to form the electrolyte layer 7. Is compressed in a direction perpendicular to the surface, and the sealing material 8 is cured by heating to perform sealing. At this time, the thickness of the porous film constituting the electrolyte layer 7 is reduced by compression, but the final porosity of the porous film is set to a desired value.
Thus, the target dye-sensitized photoelectric conversion element is manufactured.

  On the other hand, in the dye-sensitized photoelectric conversion element, when the counter electrode 6 made of porous carbon or porous metal having a bulk (or thickness) is used, in addition to the bulk of the porous electrode 3, the counter electrode 6 is used. In consideration of the bulk, an integral film of the electrolyte layer 7 and the sealing material 8 is formed. 21A and 21B show a method for manufacturing such a dye-sensitized photoelectric conversion element.

  As shown in FIG. 21A, in the method of manufacturing the dye-sensitized photoelectric conversion element, first, the porous electrode 3 is formed in the same manner as in the first embodiment.

  On the other hand, as shown in FIG. 21A, an integrated film is prepared in which, for example, a thermosetting sealing material 8 is formed integrally with the electrolyte layer 7 on the outer periphery of the electrolyte layer 7 made of a porous film containing an electrolytic solution. The thickness of the electrolyte layer 7 in this state is larger than the final thickness of the electrolyte layer 7. The thickness of the sealing material 8 is larger than the thickness of the electrolyte layer 7, so that the sealing material 8 can finally be sufficiently sealed. In addition, a device in which a counter electrode 6 is provided on a counter substrate 4 via a conductive layer 5 is prepared.

Next, as shown in FIG. 21B, an integral membrane in which a sealing material 8 is formed on the outer periphery of an electrolyte layer 7 made of a porous membrane containing an electrolytic solution is placed on the porous electrode 3, and then the electrolyte layer 7 The counter electrode 6 provided on the counter substrate 4 is placed on the sealing material 8, and the counter substrate 4 is pressed against the electrolyte layer 7. Thus, the electrolyte layer 7 is compressed in a direction perpendicular to the surface, and the sealing material 8 is cured by heating to perform sealing. At this time, the thickness of the porous film constituting the electrolyte layer 7 is reduced by compression, but the final porosity of the porous film is set to a desired value.
Thus, the target dye-sensitized photoelectric conversion element is manufactured.

About things other than the above, it is the same as that of 1st Embodiment.
According to the thirteenth embodiment, in addition to the same advantages as those of the first and twelfth embodiments, the process of forming the sealing material 8 can be omitted. The advantage that it can be manufactured more easily can be obtained.

<14. Fourteenth Embodiment>
[Dye-sensitized photoelectric conversion element]
The dye-sensitized photoelectric conversion element, except that a third additive _{6.04 ≦ pK a (H 2 O} ) ≦ 7.3 in the electrolyte solution constituting the electrolyte layer 7 is added, the This is the same as the dye-sensitized photoelectric conversion element according to the first embodiment. Such a third additive is a pyridine-based additive or an additive having a heterocyclic ring. Specific examples of the pyridine-based additive include 2-NH2-Py, 4-MeO-Py, 4-Et-Py and the like. Specific examples of the additive having a heterocyclic ring include MIm, 24-Lu, 25-Lu, 26-Lu, 34-Lu, and 35-Lu.

  Moreover, as a solvent of the electrolyte solution contained in the electrolyte layer 7, a solvent having a molecular weight of 47.36 or more is used. Such a solvent is, for example, 3-methoxypropionitrile (MPN), methoxyacetonitrile (MAN), a mixed solution of acetonitrile (AN) and valeronitrile (VN), or the like.

[Method for producing dye-sensitized photoelectric conversion element]
The method for manufacturing a dye-sensitized photoelectric conversion element, except for the addition of a third additive _{6.04 ≦ pK a (H 2 O} ) ≦ 7.3 in the electrolyte solution constituting the electrolyte layer 7, This is the same as the manufacturing method of the dye-sensitized photoelectric conversion element according to the first embodiment.

<Example 29>
In addition to quinuclidine (Q) as the first additive and GuOTf as the second additive, 0.054 g of 2-NH2-Py was dissolved as the third additive in the electrolytic solution of Example 1, An electrolyte solution was prepared. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Example 11.

<Example 30>
An electrolyte solution was prepared using 4-MeO-Py as the third additive. Others were carried out similarly to Example 29, and manufactured the dye-sensitized photoelectric conversion element.

<Example 31>
An electrolyte solution was prepared using 4-Et-Py as the third additive. Others were carried out similarly to Example 29, and manufactured the dye-sensitized photoelectric conversion element.

<Example 32>
An electrolyte solution was prepared using MIm as the third additive. Others were carried out similarly to Example 29, and manufactured the dye-sensitized photoelectric conversion element.

<Example 33>
An electrolyte solution was prepared using 24-Lu as the third additive. Others were carried out similarly to Example 29, and manufactured the dye-sensitized photoelectric conversion element.

<Example 34>
An electrolyte solution was prepared using 25-Lu as the third additive. Others were carried out similarly to Example 29, and manufactured the dye-sensitized photoelectric conversion element.

<Example 35>
An electrolyte solution was prepared using 26-Lu as the third additive. Others were carried out similarly to Example 29, and manufactured the dye-sensitized photoelectric conversion element.

<Example 36>
An electrolyte solution was prepared using 34-Lu as the third additive. Others were carried out similarly to Example 29, and manufactured the dye-sensitized photoelectric conversion element.

<Example 37>
An electrolyte solution was prepared using 35-Lu as the third additive. Others were carried out similarly to Example 29, and manufactured the dye-sensitized photoelectric conversion element.

<Comparative example 4>
3-Methoxypropionitrile (MPN) as solvent, 1.0 M 1-propyl-3-methylimidazolium iodide (MPImI), 0.1 M iodine I ₂ , and 0.3 M N as additive -What did not add a 1st additive and a 2nd additive to the electrolyte solution prepared by melt | dissolving a butylbenzmidazole (NBB) was used. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Example 11.

<Comparative Example 5>
An electrolyte solution was prepared using TBP as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

<Comparative Example 6>
An electrolyte solution was prepared using 4-picoline (4-pic) as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

<Comparative Example 7>
An electrolyte solution was prepared using methylisonicotinate (4-COOMe-Py) as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

<Comparative Example 8>
An electrolyte solution was prepared using 4-cyanopyridine (4-CN-Py) as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

<Comparative Example 9>
An electrolyte solution was prepared using 4-aminopyridine (4-NH2-Py) as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

<Comparative Example 10>
An electrolyte solution was prepared using 4- (methylamino) pyridine (4-MeNH-Py) as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

<Comparative Example 11>
An electrolyte solution was prepared using 3-methoxypyridine (3-MeO-Py) as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

<Comparative example 12>
An electrolyte solution was prepared using 2-methoxypyridine (2-MeO-Py) as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

<Comparative Example 13>
An electrolyte solution was prepared using methyl nicotinate (3-COOMe-Py) as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

<Comparative example 14>
An electrolyte solution was prepared using pyridine (Py) as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

<Comparative Example 15>
An electrolyte solution was prepared using 3-bromopyridine (3-Br-Py) as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

<Comparative Example 16>
An electrolyte solution was prepared using N-methylbenzimidazole (NMB) as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

<Comparative Example 17>
An electrolyte solution was prepared using pyrazine as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

<Comparative Example 18>
An electrolyte was prepared using thiazole as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

<Comparative example 19>
An electrolyte solution was prepared using N-methylpyrazole (Me-pyrazole) as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

<Comparative Example 20>
An electrolyte was prepared using quinoline as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

<Comparative example 21>
An electrolyte was prepared using isoquinoline as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

<Comparative example 22>
An electrolyte solution was prepared using 2,2′-bipyridyl (bpy) as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

<Comparative Example 23>
An electrolyte was prepared using pyridazine as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

<Comparative example 24>
An electrolyte solution was prepared using pyrimidine as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

<Comparative Example 25>
An electrolyte was prepared using acridine as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

<Comparative Example 26>
An electrolyte solution was prepared using 5,6-benzoquinoline as an additive. Otherwise, a dye-sensitized photoelectric conversion element was produced in the same manner as in Comparative Example 4.

In order to more clearly verify the effect of adding the third additive to the electrolytic solution constituting the electrolyte layer 7, instead of the electrolytic solution of Examples 29 to 37, 3-methoxypropionitrile as a solvent (MPN) with 1.0 M 1-propyl-3-methylimidazolium iodide (MPImI), 0.1 M iodine I ₂ and 0.3 M N-butylbenzimidazole (NBB) as additive. A dye-sensitized photoelectric conversion element in which a photosensitizing dye was adsorbed on the porous electrode 3 was manufactured by immersing the porous electrode 3 in a photosensitizing dye solution by using an electrolytic solution prepared by dissolution. . These dye-sensitized photoelectric conversion elements are referred to as Reference Examples 26 to 34 corresponding to Examples 29 to 37.

Table 9 shows the reference example with pyridine-based additive 26 to 28 and Comparative Examples 4-15 of pK _a (water), photoelectric conversion efficiency (Eff) and internal resistance (R _s). Table 10 Reference Example was used additives having a heterocyclic ring 29-34 and Comparative Examples _{16~26 pK a (H 2 O)} , showing a photoelectric conversion efficiency (Eff) and internal resistance (R _s). From Table 9 and Table 10, none of Reference Example 8-16 using additives _{6.04 ≦ pK a (H 2 O} ) ≦ 7.3, in Comparative Example 5 using 4-tert-butylpyridine compared to the photoelectric conversion efficiency (Eff) is at least equivalent, the internal resistance (R _s) is lower it can be seen. FIG. 22 is _a plot of photoelectric conversion efficiencies (Eff) of Reference Examples 26 to 34 and Comparative Examples 4 to 26 against pKa. FIG. 23 is _a plot of the internal resistance (R _s ) of Reference Examples 26 to 34 and Comparative Examples 4 to 26 versus pKa.

  Next, the dependency of the effect of the third additive added to the electrolytic solution on the solvent type of the electrolytic solution will be described.

The effect of the third additive was confirmed for each solvent having a different molecular weight. Here, pK _a and the was compared relatively close 4-tert-butylpyridine (TBP) and 4-Et-Py (4- ethylpyridine). The evaluation method is as follows. For each solvent, the photoelectric conversion efficiency (Eff (4-Et-Py)) of the dye-sensitized photoelectric conversion element using 4-Et-Py as the second additive of the electrolyte and the second addition of the electrolyte The photoelectric conversion efficiency (Eff (TBP)) of the dye-sensitized photoelectric conversion element using TBP as an agent is measured. Then, the difference ΔEff = Eff (4-Et−Py) −Eff (TBP) between these photoelectric conversion efficiencies is used as an effect index. As the solvent, four types of acetonitrile (AN), a mixed solution of acetonitrile (AN) and valeronitrile (VN), methoxyacetonitrile (MAN), and 3-methoxypropionitrile (MPN) were used. Table 11 shows the molecular weight, Eff (4-Et-Py), Eff (TBP) and ΔEff for each solvent. However, the values of Eff (4-Et-Py), Eff (TBP) and ΔEff relative to acetonitrile (AN) are Solar Energy Materials & Solar
Reference was made to those reported in Cells, 2003, 80, 167. FIG. 24 is a plot of the photoelectric conversion efficiency difference ΔEff against the molecular weight of each solvent.

  From Table 11 and FIG. 24, it can be seen that ΔEff> 0, in other words, Eff (4-Et-Py) is larger than Eff (TBP) in the molecular weight range of 47.36 or more. However, the value 47.36 is an apparent molecular weight calculated using the mixture volume fraction of a mixture of acetonitrile (AN) and valeronitrile (VN).

From the above, in a solvent having a molecular weight of more than 47.36, the use of _{6.04 ≦ pK a (H 2 O} ) ≦ 7.3 additives as a second additive of the electrolyte, the effect You can see that there is.

As described above, according to the fourteenth embodiment, a _{6.04 ≦ pK a (H 2 O} ) ≦ 7.3 additives as a third additive to the electrolyte solution constituting the electrolyte layer 7 Therefore, in addition to the same advantages as those of the first embodiment, the following advantages can be obtained. That is, compared with a conventional dye-sensitized photoelectric conversion element using 4-tert-butylpyridine as an additive for an electrolytic solution, an equivalent or higher photoelectric conversion efficiency and an equivalent or lower internal resistance can be obtained. A dye-sensitized photoelectric conversion element having conversion characteristics can be obtained. Further, since there are various third additives with 6.04 ≦ pK _a (H ₂ O) ≦ 7.3, the range of selection of the third additive is extremely wide.

<15. Fifteenth Embodiment>
[Dye-sensitized photoelectric conversion element]
In this dye-sensitized photoelectric conversion element, the porous electrode 3 is formed of metal / metal oxide fine particles, and is typically formed by sintering these metal / metal oxide fine particles. FIG. 25 shows details of the structure of the metal / metal oxide fine particles 41. As shown in FIG. 25, the metal / metal oxide fine particles 41 have a core / shell structure composed of a spherical core 41a made of metal and a shell 41b made of metal oxide surrounding the core 41a. One or more kinds of photosensitizing dyes (not shown) are bonded (or adsorbed) to the surface of the shell 41b made of the metal oxide of the metal / metal oxide fine particles 41.

Examples of the metal oxide constituting the shell 41b of the metal / metal oxide fine particles 41 include titanium oxide (TiO ₂ ), tin oxide (SnO ₂ ), niobium oxide (Nb ₂ O ₅ ), and zinc oxide (ZnO). Used. Among these metal oxides, it is preferable to use TiO ₂ , especially anatase TiO ₂ . However, the kind of metal oxide is not limited to these, and two or more kinds of metal oxides can be mixed or combined as needed. Further, the form of the metal / metal oxide fine particles 41 may be any of a granular shape, a tube shape, a rod shape, and the like.

  The particle diameter of the metal / metal oxide fine particles 41 is not particularly limited, but is generally 1 to 500 nm as an average particle diameter of primary particles, particularly preferably 1 to 200 nm, particularly preferably 5 to 100 nm. is there. The particle size of the core 41a of the metal / metal oxide fine particles 41 is generally 1 to 200 nm.

[Method for producing dye-sensitized photoelectric conversion element]
The method for manufacturing the dye-sensitized photoelectric conversion element is the same as the method for manufacturing the dye-sensitized photoelectric conversion element of the first embodiment except that the porous electrode 3 is formed of the metal / metal oxide fine particles 41. It is.

The metal / metal oxide fine particles 41 constituting the porous electrode 3 can be formed by a conventionally known method (for example, Jpn. J. Appl. Phys. Vol. 46, No. 4B, 2007, pp. 2567-). 2570). As an example, an outline of a method for producing metal / metal oxide fine particles 41 in which the core 41a is made of Au and the shell 41b is made of TiO ₂ is as follows. That is, first, dehydrated trisodium citrate is mixed and stirred in a heated solution of 5 × 10 ⁻⁴ M HAuCl _{4 in} 500 mL. Next, mercaptoundecanoic acid is added to the aqueous ammonia solution by 2.5 wt% and stirred, and then added to the Au nanoparticle dispersion solution and kept warm for 2 hours. Next, 1M HCl is added to bring the pH of the solution to 3. Next, titanium isopropoxide and triethanolamine are added to the Au colloid solution under a nitrogen atmosphere. In this way, metal / metal oxide fine particles 41 having the core 41a made of Au and the shell 41b made of TiO ₂ are manufactured.

[Operation of dye-sensitized photoelectric conversion element]
Next, the operation of this dye-sensitized photoelectric conversion element will be described.
When light is incident, the dye-sensitized photoelectric conversion element operates as a battery having the counter electrode 6 as a positive electrode and the transparent electrode 2 as a negative electrode. The principle is as follows. Here, FTO is used as the material of the transparent electrode 2, Au is used as the material of the core 41 a of the metal / metal oxide fine particles 41 constituting the porous electrode 3, TiO ₂ is used as the material of the shell 41 b, and the redox pair is used. It is assumed that a redox species of I ⁻ / I ₃ ⁻ is used. However, it is not limited to this.

When a photosensitizing dye that has passed through the transparent substrate 1 and the transparent electrode 2 and has entered the porous electrode 3 and has been bonded to the porous electrode 3 absorbs the photons, the electrons in the photosensitizing dye are released from the ground state (HOMO). Excited to an excited state (LUMO). The electrons excited in this way are formed of TiO ₂ constituting the shell 41b of the metal / metal oxide fine particles 41 constituting the porous electrode 3 through electrical coupling between the photosensitizing dye and the porous electrode 3. It is drawn out to the conduction band and reaches the transparent electrode 2 through the porous electrode 3. In addition, when light enters the surface of the core 41a made of Au of the metal / metal oxide fine particles 41, the localized surface plasmons are excited, and an electric field enhancing effect is obtained. A large amount of electrons are excited in the conduction band of TiO ₂ constituting the shell 41 b by this enhanced electric field, and reach the transparent electrode 2 through the porous electrode 3. Thus, when light is incident on the porous electrode 3, electrons generated by excitation of the photosensitizing dye reach the transparent electrode 2, and in addition, the core 41 a of the metal / metal oxide fine particles 41. Electrons excited in the conduction band of TiO ₂ constituting the shell 41b also arrive by excitation of localized surface plasmons on the surface. For this reason, high photoelectric conversion efficiency can be obtained.

On the other hand, the photosensitizing dye that has lost electrons receives electrons from the reducing agent in the electrolyte layer 7, for example, I ^−, by the following reaction, and the oxidant, for example, I ₃ ⁻ (I ₂ and I ⁻ To form a conjugate).
2I ⁻ → I ₂ + 2e ^{−
_{I 2 + I - → I 3}} -

The oxidant thus generated reaches the counter electrode 6 by diffusion, receives electrons from the counter electrode 6 by the reverse reaction of the above reaction, and is reduced to the original reducing agent.
^{_{I 3 - → I 2 + I}} -
I ₂ + 2e ^- → 2I ^-

  The electrons sent from the transparent electrode 2 to the external circuit return to the counter electrode 6 after performing electrical work in the external circuit. In this way, light energy is converted into electrical energy without leaving any change in the photosensitizing dye or the electrolyte layer 7.

  According to the fifteenth embodiment, in addition to the same advantages as the first embodiment, the following advantages can be obtained. That is, the porous electrode 3 is composed of metal / metal oxide fine particles 41 having a core / shell structure composed of a spherical core 41a made of metal and a shell 41b made of metal oxide surrounding the core 41a. Yes. For this reason, when the electrolyte layer 7 is filled between the porous electrode 3 and the counter electrode 6, the electrolyte of the electrolyte layer 7 does not come into contact with the core 41 a made of metal of the metal / metal oxide fine particles 41, and the electrolyte It is possible to prevent the porous electrode 3 from being dissolved. Accordingly, gold, silver, copper, or the like having a large surface plasmon resonance effect can be used as the metal constituting the core 41a of the metal / metal oxide fine particles 41, and the surface plasmon resonance effect can be sufficiently obtained. Further, an iodine-based electrolyte can be used as the electrolyte of the electrolyte layer 7. As described above, a dye-sensitized photoelectric conversion element having high photoelectric conversion efficiency can be obtained. By using this excellent dye-sensitized photoelectric conversion element, a high-performance electronic device can be realized.

<16. Sixteenth Embodiment>
[Photoelectric conversion element]
This photoelectric conversion element is the same as the dye-sensitized photoelectric conversion element according to the fifteenth embodiment except that the photosensitizing dye is not adsorbed on the metal / metal oxide fine particles 41 constituting the porous electrode 3. It is.

[Production Method of Photoelectric Conversion Element]
This photoelectric conversion element manufacturing method is the same as that of the dye-sensitized photoelectric conversion element according to the fifteenth embodiment except that the photosensitizing dye is not adsorbed to the metal / metal oxide fine particles 41 constituting the porous electrode 3. This is the same as the manufacturing method.

[Operation of photoelectric conversion element]
Next, the operation of this photoelectric conversion element will be described.
When light enters, this photoelectric conversion element operates as a battery having the counter electrode 6 as a positive electrode and the transparent electrode 2 as a negative electrode. The principle is as follows. Here, FTO is used as the material of the transparent electrode 2, Au is used as the material of the core 41 a of the metal / metal oxide fine particles 41 constituting the porous electrode 3, TiO ₂ is used as the material of the shell 41 b, and the redox pair is used. It is assumed that a redox species of I ⁻ / I ₃ ⁻ is used. However, it is not limited to this.

Light is incident on the surface of the core 41a made of Au of the metal / metal oxide fine particles 41 constituting the porous electrode 3 through the transparent substrate 1 and the transparent electrode 2, and thereby the localized surface plasmon is excited and the electric field is enhanced. An effect is obtained. A large amount of electrons are excited in the conduction band of TiO ₂ constituting the shell 41 b by this enhanced electric field, and reach the transparent electrode 2 through the porous electrode 3.

On the other hand, the porous electrode 3 that has lost the electrons receives electrons from the reducing agent in the electrolyte layer 7, such as I ^−, by the following reaction, and oxidants such as I ₃ ⁻ (I ₂ and I ⁻ To form a conjugate).
2I ⁻ → I ₂ + 2e ^{−
_{I 2 + I - → I 3}} -

The oxidant thus generated reaches the counter electrode 6 by diffusion, receives electrons from the counter electrode 6 by the reverse reaction of the above reaction, and is reduced to the original reducing agent.
^{_{I 3 - → I 2 + I}} -
I ₂ + 2e ^- → 2I ^-

The electrons sent from the transparent electrode 2 to the external circuit return to the counter electrode 6 after performing electrical work in the external circuit. In this way, light energy is converted into electrical energy without leaving any change in the photosensitizing dye or the electrolyte layer 7.
According to the fifteenth embodiment, advantages similar to those of the first embodiment can be obtained.

Although the embodiments and examples have been specifically described above, the invention is not limited to the above-described embodiments and examples, and various modifications can be made.
For example, the numerical values, structures, configurations, shapes, materials, and the like given in the above-described embodiments and examples are merely examples, and different numerical values, structures, configurations, shapes, materials, etc. are used as necessary. Also good.

  DESCRIPTION OF SYMBOLS 1 ... Transparent substrate, 2 ... Transparent electrode, 3 ... Porous electrode, 4 ... Opposite substrate, 5 ... Conductive layer, 6 ... Counter electrode, 7 ... Electrolyte layer, 8 ... Sealing material, 9, 9a, 9b, 10-17 , 23, 27 ... retaining material, 18 ... electrolyte, 19, 30 ... film electrode, 41 ... metal / metal oxide fine particles, 41a ... core, 41b ... shell

Claims (20)

  The photoelectric conversion element which has an electrolyte layer which consists of an iodine redox type electrolyte solution containing the additive which consists of a compound which shows a stronger interaction with an iodine molecule than an iodide ion between a porous electrode and a counter electrode. The additives described above, pK _a (H ₂ O) is pK _a (H ₂ O) ionic addition of more than 4.76 of a non-ionic additives and / or anionic conjugate acid of more than 9.12 of conjugate acid The photoelectric conversion element according to claim 1, which is an agent.   The photoelectric conversion element according to claim 2, wherein the nonionic additive is at least one selected from the group consisting of a heterocyclic compound, a cyclic amine, a chain amine, a diamine, an amidine, a guanidine, and a phosphazene.   The photoelectric conversion element according to claim 3, wherein the nonionic additive is at least one selected from the group consisting of 4-N, N-dimethylaminopyridine, 4-pyrrolidinopyridine, quinuclidine, and 4-aminopyridine. .   The photoelectric conversion element according to claim 2, wherein the ionic additive is a compound containing at least one selected from the group consisting of a carboxy anion, an alkoxy anion, a mercapto anion, a carbon anion, and an amide anion.   6. The photoelectric conversion element according to claim 5, wherein the ionic additive is 1-ethyl-3-methylimidazolium acetate and / or 1-ethyl-3-methylimidazolium decanonate.   The photoelectric conversion element according to claim 1, wherein the electrolyte layer is made of a porous film containing the electrolytic solution.   The photoelectric conversion element according to claim 7, wherein the porous film is made of a nonwoven fabric.   The photoelectric conversion element according to claim 8, wherein the nonwoven fabric is made of polyolefin, polyester, or cellulose.   The photoelectric conversion element according to claim 9, wherein the porosity of the porous film is 80% or more and less than 100%.   The photoelectric conversion element according to claim 1, wherein the photoelectric conversion element is a dye-sensitized photoelectric conversion element in which a photosensitizing dye is bonded to the porous electrode.   The photoelectric conversion element according to claim 11, wherein the porous electrode is composed of fine particles made of a semiconductor.   The photoelectric conversion element according to claim 1, wherein the solvent of the electrolytic solution contains an ionic liquid having an electron pair accepting functional group and an organic solvent having an electron pair donating functional group.   Manufacture of a photoelectric conversion element having a step of forming an electrolyte layer provided between a porous electrode and a counter electrode with an iodine redox electrolyte containing an additive composed of a compound having a stronger interaction with iodine molecules than iodide ions Method. The additives described above, pK _a (H ₂ O) is pK _a (H ₂ O) ionic addition of more than 4.76 of a non-ionic additives and / or anionic conjugate acid of more than 9.12 of conjugate acid The method for producing a photoelectric conversion element according to claim 14, which is an agent.   The method for producing a photoelectric conversion element according to claim 15, wherein the nonionic additive is at least one selected from the group consisting of a heterocyclic compound, a cyclic amine, a chain amine, a diamine, an amidine, a guanidine, and a phosphazene.   The photoelectric conversion element according to claim 16, wherein the nonionic additive is at least one selected from the group consisting of 4-N, N-dimethylaminopyridine, 4-pyrrolidinopyridine, quinuclidine, and 4-aminopyridine. Manufacturing method.   The method for producing a photoelectric conversion element according to claim 15, wherein the ionic additive is a compound containing at least one selected from the group consisting of a carboxy anion, an alkoxy anion, a mercapto anion, a carbon anion, and an amide anion.   The method for producing a photoelectric conversion element according to claim 18, wherein the ionic additive is 1-ethyl-3-methylimidazolium acetate and / or 1-ethyl-3-methylimidazolium decanonate. Having at least one photoelectric conversion element;
The photoelectric conversion element is
An electronic device that is a photoelectric conversion element having an electrolyte layer made of an iodine redox electrolyte solution containing an additive made of a compound that has a stronger interaction with iodine molecules than iodide ions between a porous electrode and a counter electrode.

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