JP5298449B2 - Photoelectric conversion element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric conversion element capable of improving conversion efficiency. <P>SOLUTION: The dye is indicated by formula (1), and includes a cyanine dye having an indolenin frame. Thus, the dye absorbing light can easily implant an electron into a metal oxide semiconductor layer 12. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a photoelectric conversion element using a dye.

  2. Description of the Related Art Conventionally, as a photoelectric conversion element such as a solar cell that converts light energy such as sunlight into electric energy, a dye-sensitized photoelectric conversion element that supports and sensitizes a dye on an electrode having an oxide semiconductor is known. This dye-sensitized photoelectric conversion element can be expected to have a theoretically high efficiency, and is considered to be very advantageous in terms of cost compared to a photoelectric conversion element using a silicon semiconductor that is generally spread. For this reason, it has been attracting attention as a next-generation photoelectric conversion element, and is being developed for practical use.

With respect to the dye used for the dye-sensitized photoelectric conversion element, a technique using an organic dye such as a cyanine dye is known for the purpose of improving conversion efficiency (see, for example, Patent Document 1). Moreover, it is thought that it is effective for the improvement of conversion efficiency because a pigment | dye molecule | numerator has an electron withdrawing group.
JP 2000-294303 A

  However, in the photoelectric conversion element using the conventional pigment | dye, sufficient conversion efficiency is not obtained and the further improvement is desired.

  This invention is made | formed in view of this problem, The objective is to provide the photoelectric conversion element which can improve conversion efficiency.

  The photoelectric conversion element of the present invention includes an electrode having a dye and a carrier that supports the dye, and the dye includes a compound represented by Chemical Formula 1.

（Ｒ１、Ｒ２、Ｒ３およびＲ４は１価の置換基であり、それぞれは互いに同一でもよいし異なってもよい。ただし、Ｒ１、Ｒ２、Ｒ３およびＲ４からなる群のうちの少なくとも１つはアンカー基またはアンカー基を有する基である。Ｒ５およびＲ６は１価の置換基であり、それぞれは互いに同一でもよいし異なってもよい。Ｒ７、Ｒ８およびＲ９は水素原子または１価の置換基であり、それぞれは互いに同一でもよいし異なってもよく、互いに結合して環状構造を形成してもよい。環Ａおよび環Ｂはベンゼン環、ナフタレン環、置換基を有するベンゼン環または置換基を有するナフタレン環である。ｎは０以上の整数である。なお、アンカー基とは、担持体と化学的に結合することができる電子吸引性の基である。）

(R1, R2, R3 and R4 are monovalent substituents, each of which may be the same or different from each other, provided that at least one of the group consisting of R1, R2, R3 and R4 is an anchor group. Or R5 and R6 are monovalent substituents, which may be the same or different from each other, R7, R8 and R9 are hydrogen atoms or monovalent substituents; Each may be the same as or different from each other, and may be bonded to each other to form a cyclic structure.Ring A and Ring B are a benzene ring, a naphthalene ring, a benzene ring having a substituent, or a naphthalene ring having a substituent. N is an integer greater than or equal to 0. The anchor group is an electron-withdrawing group that can be chemically bonded to the carrier.

  In the photoelectric conversion element of the present invention, since the dye contains the compound shown in Chemical Formula 1, the dye that has absorbed light can easily inject electrons into the carrier. Thereby, photoelectric conversion is performed efficiently.

  In the photoelectric conversion element of the present invention, at least one of R5 and R6 shown in Chemical Formula 1 is any one of an alkyl group, an alkenyl group, a substituted alkyl group, and a substituted alkenyl group. Also good.

  Furthermore, in the photoelectric conversion element of this invention, it is preferable that an above-described anchor group is a carboxylic acid group. The group having an anchor group is preferably a carboxylic acid group having an alkyl chain. Moreover, it is preferable that a support body contains at least 1 sort (s) of a titanium oxide and a zinc oxide. As a result, the dye absorbs light and electrons are easily injected into the carrier.

  According to the photoelectric conversion element of the present invention, since an electrode having a dye and a carrier that supports the dye is provided and the dye contains the compound shown in Chemical Formula 1, the conversion efficiency can be improved.

  Further, higher conversion efficiency can be obtained by including in the dye a compound in which the anchor group shown in Chemical Formula 1 is a carboxylic acid group or a compound in which the anchor group-containing group is a carboxylic acid group having an alkyl chain. It is done. Furthermore, high conversion efficiency is obtained because the carrier includes at least one of titanium oxide and zinc oxide.

  Hereinafter, the best mode for carrying out the present invention (hereinafter simply referred to as an embodiment) will be described in detail with reference to the drawings.

  FIG. 1 schematically shows a cross-sectional configuration of a photoelectric conversion element according to an embodiment of the present invention, and FIG. 2 shows an extracted and enlarged main part of the photoelectric conversion element shown in FIG. Is. The photoelectric conversion element shown in FIGS. 1 and 2 is a main part of a so-called dye-sensitized solar cell. In this photoelectric conversion element, the working electrode 10 and the counter electrode 20 are arranged to face each other with the electrolyte-containing body 30 interposed therebetween, and at least one of the working electrode 10 and the counter electrode 20 is an electrode having optical transparency. It is.

  The working electrode 10 has, for example, a structure in which a metal oxide semiconductor layer 12 is provided on a conductive substrate 11 and a dye 14 is supported using the metal oxide semiconductor layer 12 as a carrier. The working electrode 10 functions as a negative electrode for the external circuit. For example, the conductive substrate 11 is obtained by providing a conductive layer 11B on the surface of an insulating substrate 11A.

  Examples of the material of the substrate 11A include insulating materials such as glass, plastic, and transparent polymer film. Examples of the transparent polymer film include tetraacetyl cellulose (TAC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), syndioctane polyester (SPS), polyphenylene sulfide (PPS), polycarbonate (PC), and polyarylate. (PAr), polysulfone (PSF), polyester sulfone (PES), polyetherimide (PEI), cyclic polyolefin, or brominated phenoxy.

Examples of the conductive layer 11B include conductive metal oxide thin films such as indium oxide, tin oxide, indium-tin composite oxide (ITO), or tin oxide doped with fluorine (FTO: F-SnO ₂ ), Examples thereof include metal thin films such as gold (Au), silver (Ag), and platinum (Pt), and those formed of a conductive polymer.

  In addition, the conductive substrate 11 may be configured to have a single-layer structure with, for example, a conductive material. In that case, examples of the material of the conductive substrate 11 include indium oxide, tin oxide, Examples thereof include conductive metal oxides such as indium-tin composite oxide or tin oxide doped with fluorine, metals such as gold, silver or platinum, and conductive polymers.

  The metal oxide semiconductor layer 12 is formed of, for example, a dense layer 12A and a porous layer 12B. A dense layer 12A is formed at the interface with the conductive substrate 11, and the dense layer 12A is preferably dense and has few voids, and more preferably in the form of a film. A porous layer 12B is formed on the surface in contact with the electrolyte-containing body 30, and the porous layer 12B preferably has a structure with many voids and a large surface area, and particularly has a structure in which porous fine particles are attached. More preferred. The metal oxide semiconductor layer 12 may be formed to have a film-like single layer structure, for example.

  Examples of the metal oxide semiconductor material include titanium oxide, zinc oxide, tin oxide, niobium oxide, indium oxide, zirconium oxide, tantalum oxide, vanadium oxide, yttrium oxide, aluminum oxide, and magnesium oxide. Among these, the metal oxide semiconductor material preferably contains at least one of titanium oxide and zinc oxide, and more preferably contains zinc oxide. This is because a high conversion efficiency can be obtained because the compound shown in Chemical Formula 1 is contained in the dye 14. These metal oxide semiconductors may be used alone or in combination of two or more (mixed, mixed crystal, solid solution, etc.), for example, zinc oxide and tin oxide. Also, a combination of titanium oxide and niobium oxide can be used.

  The dye 14 supported on the metal oxide semiconductor layer 12 contains the compound shown in Chemical Formula 1. This compound is included because excellent conversion efficiency can be obtained. This is because at least one of the group consisting of R1, R2, R3 and R4 shown in Chemical formula 1 is an anchor group or a group having an anchor group, so that the lowest unoccupied molecular orbital of the compound shown in Chemical formula 1 ( LUMO) is closer to the surface of the metal oxide semiconductor, and in addition to injecting electrons through the anchor group, electrons can be injected into the metal oxide semiconductor layer 12 without through the anchor group. Guessed.

The compound shown in Chemical formula 1 has an anchor group. The anchor group is an electron-withdrawing substituent that can be chemically bonded to the metal oxide semiconductor layer 12. Examples of the anchor group include a carboxylic acid group (—COOH), a phosphoric acid group (—PO ₃ H ₂ , —PO ₄ H ₂ ), a sulfonic acid group (—SO ₃ H), and a boric acid group (—B ( OH) ₂ ) or derivatives thereof. Among these, a carboxylic acid group is preferable. This is because high conversion efficiency can be obtained. Further, the group having an anchor group shown in Chemical Formula 1 is preferably a carboxylic acid group having an alkyl chain (— (CH ₂ ) _m —COOH: m is an integer of 1 or more). This is because high conversion efficiency can be obtained.

  In addition, at least one of R5 and R6 shown in Chemical Formula 1 is preferably any one of an alkyl group, an alkenyl group, a substituted alkyl group, and a substituted alkenyl group. This is because it is difficult to form an aggregate on the surface of the metal oxide semiconductor layer 12.

  Examples of the compound represented by Chemical Formula 1 include compounds represented by Chemical Formulas 2 (1) to (4) or Chemical Formula 3 (1) to (3).

  It is needless to say that the compound having the structure shown in Chemical Formula 1 is not limited to the compounds shown in Chemical Formula 2 and Chemical Formula 3.

  Moreover, the pigment | dye 14 may contain another pigment | dye other than said pigment | dye. The other dye is preferably a dye having an electron-withdrawing substituent that can be chemically bonded to the metal oxide semiconductor layer 12. Examples of other dyes include eosin Y, dibromofluorescein, fluorescein, rhodamine B, pyrogallol, dichlorofluorescein, erythrosine B (erythrocin is a registered trademark), fluorescin, mercurochrome, cyanine dye, merocyanine disazo dye, trisazo dye, Anthraquinone dyes, polycyclic quinone dyes, indigo dyes, diphenylmethane dyes, trimethylmethane dyes, quinoline dyes, benzophenone dyes, naphthoquinone dyes, perylene dyes, fluorenone dyes, squarylium dyes, azurenium dyes And organic dyes such as perinone dyes, quinacridone dyes, metal-free phthalocyanine dyes and metal-free porphyrin dyes.

  Examples of other dyes include organometallic complex compounds. For example, an ionic coordinate bond formed by a nitrogen anion and a metal cation in an aromatic heterocyclic ring, and a nitrogen atom or Organometallic complex compounds having both nonionic coordination bonds formed between chalcogen atoms and metal cations, ionic coordination bonds formed by oxygen anions or sulfur anions and metal cations, and nitrogen And organometallic complex compounds having both nonionic coordination bonds formed between an atom or chalcogen atom and a metal cation. Specifically, metal phthalocyanine dyes such as copper phthalocyanine and titanyl phthalocyanine, metal naphthalocyanine dyes, metal porphyrin dyes, bipyridyl ruthenium complexes, terpyridyl ruthenium complexes, phenanthroline ruthenium complexes, bicinchonirate ruthenium complexes, and azo ruthenium complexes Alternatively, a ruthenium complex such as a quinolinol ruthenium complex can be used.

  The counter electrode 20 is obtained, for example, by providing a conductive layer 22 on a conductive substrate 21. The counter electrode 20 functions as a positive electrode for an external circuit. Examples of the material of the conductive substrate 21 include the same material as that of the conductive substrate 11 of the working electrode 10. Examples of the conductive material used for the conductive layer 22 include metals such as platinum, gold, silver, copper (Cu), rhodium (Rh), ruthenium (Ru), aluminum (Al), magnesium (Mg), and indium (In). , Carbon (C), or a conductive polymer. These conductive materials may be used alone or in combination of two or more. Further, for example, an acrylic resin, a polyester resin, a phenol resin, an epoxy resin, cellulose, a melamine resin, a fluoroelastomer, or a polyimide resin may be used as a binder as necessary. The counter electrode 20 may have a single layer structure of the conductive layer 22, for example.

Examples of the electrolyte-containing body 30 include those containing a redox electrolyte. Examples of redox electrolytes include I ⁻ / I ₃ ⁻ system, Br ⁻ / Br ₃ ⁻ system, and quinone / hydroquinone system. Such redox electrolytes are selected from, for example, cesium halides, quaternary alkyl ammoniums, imidazolium halides, thiazolium halides, oxazolium halides, quinolinium halides, pyridinium halides. A combination of one or more of the above and a single halogen can be used. Specifically, tetraethylammonium iodide, tetrapropylammonium iodide, tetrabutylammonium iodide, tetrapentylammonium iodide, tetrahexylammonium iodide, tetraheptyl as cesium iodide and quaternary alkylammonium iodides. Ammonium iodide or trimethylphenylammonium iodide, 3-methylimidazolium iodide or 1-propyl-2,3-dimethylimidazolium iodide as imidazolium iodide, or 3-ethyl as thiazolium iodide 2-methyl-2-thiazolium iodide, 3-ethyl-5- (2-hydroxyethyl) -4-methylthiazolium iodide, 3-ethyl-2-methylbenzothiazolium iodide, Select from 3-ethyl-2-methyl-benzoxazolium iodide as oxazolium iodide, 1-ethyl-2-methylquinolinium iodide, and pyridinium iodide as quinolinium iodides A combination of one or more of the above and iodine, or a combination of quaternary alkyl ammonium bromide and bromine can be used. The electrolyte-containing body 30 may be a liquid electrolyte or a solid polymer electrolyte in which the electrolyte-containing body 30 is contained in a polymer material. As the solvent for the liquid electrolyte, an electrochemically inert solvent is used, and examples thereof include acetonitrile, propylene carbonate, and ethylene carbonate.

  Further, as the electrolyte-containing body 30, for example, a solid charge transfer layer such as a solid electrolyte may be provided instead of the redox electrolyte. The solid charge transfer layer includes, for example, a material in which carrier transfer in a solid is involved in electrical conduction. As this material, an electron transport material, a hole transport material, or the like is preferable.

  As the hole transport material, aromatic amines, triphenylene derivatives, and the like are preferable. For example, oligothiophene compounds, polypyrrole, polyacetylene or derivatives thereof, poly (p-phenylene) or derivatives thereof, and poly (p-phenylene vinylene). Alternatively, organic conductive polymers such as derivatives thereof, polythienylene vinylene or derivatives thereof, polythiophene or derivatives thereof, polyaniline or derivatives thereof, polytoluidine or derivatives thereof, and the like can be given.

  Further, as the hole transport material, for example, a p-type inorganic compound semiconductor may be used. The p-type inorganic compound semiconductor preferably has a band gap of 2 eV or more, and more preferably 2.5 eV or more. Further, the ionization potential of the p-type inorganic compound semiconductor needs to be smaller than the ionization potential of the working electrode 10 from the condition that the holes of the dye can be reduced. Although the preferable range of the ionization potential of the p-type inorganic compound semiconductor varies depending on the dye used, it is generally preferably in the range of 4.5 eV to 5.5 eV, and more preferably in the range of 4.7 eV to 5.3 eV. More preferably, it is within.

Examples of the p-type inorganic compound semiconductor include a compound semiconductor containing monovalent copper. Examples of the compound semiconductor containing monovalent _copper, there _{CuI, CuSCN, CuInSe 2, Cu} (In, Ga) Se 2, CuGaSe 2, Cu 2 O, CuS, etc. _{CuGaS 2, CuInS 2, CuAlSe 2} . Examples of other p-type inorganic compound semiconductors include GaP, NiO, CoO, FeO, Bi ₂ O ₃ , MoO _{2, and} Cr ₂ O ₃ .

  As a method of forming such a solid charge transfer layer, for example, there is a method of forming a solid charge transfer layer directly on the working electrode 10, and then the counter electrode 20 may be formed and applied.

  A hole transport material containing an organic conductive polymer may be introduced into the electrode by a technique such as vacuum deposition, casting, coating, spin coating, dipping, electrolytic polymerization, or photoelectrolytic polymerization. Can do. Also in the case of an inorganic solid compound, it can be introduced into the electrode by a technique such as a casting method, a coating method, a spin coating method, a dipping method, or an electrolytic plating method.

  A part of the solid charge transfer layer (particularly, having a hole transport material) formed in this way partially penetrates into the gap of the porous structure of the metal oxide semiconductor layer 12 and is in direct contact with it. It is preferable to become.

  This photoelectric conversion element can be manufactured as follows, for example.

  First, for example, the metal oxide semiconductor layer 12 is formed on the surface of the conductive substrate 11 on which the conductive layer 11B is formed, and the dye 14 is supported on the metal oxide semiconductor layer 12, thereby producing the photoelectrode 10. . When the metal oxide semiconductor layer 12 is formed, a metal oxide semiconductor powder is dispersed in a metal oxide semiconductor sol solution to form a metal oxide slurry, and the metal oxide slurry is formed into the conductive substrate 11. It is fired after being applied and dried. Further, the metal oxide semiconductor layer 12 may be formed by, for example, electrolytic deposition. The conductive substrate 11 on which the metal oxide semiconductor layer 12 is formed is immersed in a dye solution in which the dye 14 is dissolved in an organic solvent, and the dye 14 is supported.

  Next, for example, the counter electrode 20 is produced by forming the conductive layer 22 on one surface of the conductive substrate 21. The conductive layer 22 is formed, for example, by sputtering a conductive material.

  Subsequently, the surface of the working electrode 10 carrying the dye 14 and the surface of the counter electrode 20 on which the conductive layer 22 is formed are arranged so as to face each other while maintaining a predetermined distance. An electrolyte containing body 30 is injected between the working electrode 10 and the counter electrode 20 to seal the whole. Thus, the photoelectric conversion element shown in FIGS. 1 and 2 is completed.

  In this photoelectric conversion element, when light (sunlight or visible light equivalent to sunlight) is applied to the dye 14 carried on the working electrode 10, the dye 14 that absorbs and excites light to convert electrons into a metal oxide semiconductor. Inject into layer 12. As a result, a potential difference is generated between the counter electrode 20 and a current flows between the two electrodes for photoelectric conversion.

  According to this photoelectric conversion element, the working electrode 10 having the dye 14 and the metal oxide semiconductor layer 12 supporting the dye 14 is provided, and the dye 14 includes the compound shown in Chemical Formula 1, so that the dye 14 is Compared with the case where the compound represented by this is included, conversion efficiency can be improved.

  Further, by including in the dye 14 a compound in which the anchor group shown in Chemical Formula 1 is a carboxylic acid group or a compound in which the anchor group-containing group is a carboxylic acid group having an alkyl chain, higher conversion efficiency can be obtained. can get.

  Furthermore, if the metal oxide semiconductor material contains at least one of titanium oxide and zinc oxide, high conversion efficiency can be obtained.

  Specific examples of the present invention will be described in detail.

Example 1
As specific examples of the photoelectric conversion element described in the above embodiment, a dye-sensitized solar cell using titanium oxide as a material for a metal oxide semiconductor and a dye-sensitized solar cell using zinc oxide are as follows. It was made with.

  First, the working electrode 10 of the dye-sensitized solar cell using titanium oxide was produced. 125 ml of titanium isopropoxide was added to 750 ml of 0.1 mol / l nitric acid aqueous solution with stirring, and vigorously stirred at 80 ° C. for 8 hours. The obtained liquid was treated with an autoclave at 230 ° C. for 16 hours in a pressure vessel made of Teflon (registered trademark). After that, the sol solution containing the precipitate was resuspended by stirring. Next, the precipitate which was not resuspended was removed by suction filtration, and the sol solution was concentrated with an evaporator until the titanium oxide concentration became 11% by mass. One drop of Triton X-100 (Triton is a registered trademark) was added in order to improve the paintability on the substrate. Next, titanium oxide powder P-25 was added to this titanium oxide sol solution so that the total content of titanium oxide was 33% by mass, and the mixture was dispersed by performing centrifugal stirring using rotation revolution for 1 hour. The liquid was adjusted to obtain a metal oxide slurry.

Next, a conductive substrate 11 made of a conductive glass substrate (F-SnO ₂ ) having a length of 2.0 cm, a width of 1.5 cm, and a thickness of 1.1 mm is surrounded by a rectangle of 0.5 cm in length and 0.5 cm in width. A masking tape with a thickness of 70 μm was applied as described above, and 3 ml of metal oxide slurry was applied to this portion to a uniform thickness and dried, and then the masking tape was peeled off. Next, this substrate was baked at 500 ° C. in an electric furnace to form a metal oxide semiconductor layer 12 having a thickness of about 10 μm. The conductive substrate 11 on which the titanium oxide semiconductor layer is formed as the metal oxide semiconductor layer 12 is immersed in an absolute ethanol solution (3 × 10 ⁻⁴ mol / l) of the compound shown in Chemical Formula 2 (1) to obtain a dye. 14 was supported.

Next, a conductive layer having a thickness of 100 nm made of platinum by sputtering on one side of a conductive substrate 21 made of 2.0 cm long × 1.5 cm wide × 1.1 mm thick conductive glass substrate (F—SnO ₂ ). The counter electrode 20 was produced by forming 22. Two holes (φ1 mm) for injecting the electrolyte containing body 30 were previously formed in the conductive substrate 21. The electrolyte-containing body 30 is composed of dimethylhexylimidazolium iodide (0.6 mol / l), lithium iodide (0.1 mol / l), iodine (0.05 mol / l), water (1 mol / l) with respect to acetonitrile. ).

  Next, the surface of the working electrode 10 carrying the dye 14 and the surface of the counter electrode 20 on which the conductive layer 22 was formed were bonded together with a spacer having a thickness of 50 μm in order to maintain a predetermined distance. At this time, the spacer was disposed so as to surround the metal oxide semiconductor layer 12. Next, the electrolyte-containing body 13 prepared from the hole opened in the counter electrode 20 was injected to obtain a dye-sensitized solar cell.

In addition, a dye-sensitized solar cell was produced by the same procedure as described above except that zinc oxide was used as the metal oxide semiconductor material as the working electrode 10. At that time, the working electrode 10 was produced by the following procedure. First, a metal oxide layer made of zinc oxide is formed on a conductive substrate 11 made of a conductive glass substrate (F-SnO ₂ ) having a length of 2.0 cm, a width of 1.5 cm, and a thickness of 1.1 mm by electrolytic deposition. 12 was formed. For electrolytic deposition, 40 ml of an electrolytic bath solution adjusted to have concentrations of eosin Y (30 μmol / l), zinc chloride (5 mmol / l), and potassium chloride (0.09 mol / l) with respect to water, zinc A counter electrode made of a plate and a reference electrode made of a silver / silver chloride electrode were used. First, after bubbling this electrolytic bath with oxygen for 15 minutes, the temperature was set to 70 ° C., and a film was formed on the surface of the conductive substrate 11 while bubbling constant potential electrolysis at a potential of −1.0 V for 60 minutes. The substrate was immersed in an aqueous potassium hydroxide solution (pH 11) without drying, and then washed with water to desorb eosin Y. Subsequently, the metal oxide semiconductor layer 12 was formed by drying at 150 ° C. for 30 minutes. Next, the working electrode 10 was produced by immersing in the absolute ethanol solution (5 mmol / l) of the compound shown in Chemical Formula 2 (1) and supporting the dye 14.

(Examples 2 to 7)
Instead of the compound shown in Chemical formula 2 (1) as a dye, Chemical formula 2 (2) (Example 2), Chemical formula 2 (3) (Example 3), Chemical formula 2 (4) (Example 4), Chemical formula 2 The same procedure as in Example 1 except that the compounds shown in 3 (1) (Example 5), Chemical Formula 3 (2) (Example 6) and Chemical Formula 3 (3) (Example 7) were used. It went through.

(Comparative Examples 1-3)
Instead of the compound shown in Chemical Formula 2 (1), the chemical formula shown in Chemical Formula 4 (1) (Comparative Example 1), Chemical Formula 4 (2) (Comparative Example 2) and Chemical Formula 4 (3) (Comparative Example 3) The same procedure as in Example 1 was performed except that each compound was used.

  When the conversion efficiencies of the dye-sensitized solar cells of Examples 1 to 7 and Comparative Examples 1 to 3 were examined, the results shown in Table 1 were obtained.

The conversion efficiency was obtained by the following calculation method using an AM1.5 (1000 W / m ² ) solar simulator as the light source. First, the voltage of the dye-sensitized solar cell was swept with a source meter, and the response current was measured. As a result, a value obtained by multiplying the value obtained by dividing the maximum output, which is the product of the voltage and current by the light intensity per 1 cm ² , by multiplying by 100 was defined as the conversion efficiency (η:%). That is, the conversion efficiency is expressed by (maximum output / 1 light intensity per 1 cm ² ) × 100.

  As shown in Table 1, the conversion efficiencies in Examples 1-7 were significantly higher than those in Comparative Examples 1-3. That is, it was confirmed that the conversion efficiency can be improved by including any of the compounds shown in Chemical Formula 2 and Chemical Formula 3 in the dye 14 as compared with the case where the compound shown in Chemical Formula 4 is included. In Examples 1 to 7, since a high effect was obtained when the substituents corresponding to R5 and R6 shown in Chemical Formula 1 are methyl groups, at least one of R5 and R6 is an alkyl group, It was confirmed that sufficient conversion efficiency could be obtained if a compound that was either an alkenyl group, an alkyl group having a substituent, or an alkenyl group having a substituent was included.

  Focusing on the anchor group here, Examples 1 to 4, 6 and 6 containing the compounds shown in Chemical formulas 2 (1) to (4) and Chemical formulas 3 (2) and (3), respectively, in which the anchor group is a carboxylic acid group 7, the conversion efficiency was higher than that of Example 5 including the compound shown in Chemical Formula 3 (1) in which the anchor group was a phosphate group. That is, if the dye 14 contains the compounds shown in Chemical Formulas 2 (1) to (4) and Chemical Formulas 3 (2) and (3) in which the anchor group is a carboxylic acid group, higher conversion efficiency can be obtained. Was confirmed.

  Further, focusing on R1, R2, R3 and R4 shown in Chemical Formula 1, in Example 4 including the compound shown in Chemical Formula 2 (4) having a carboxylic acid group having an alkyl chain, Chemical Formula 2 having a carboxylic acid group Compared with Example 2 containing the compound shown in (2), the conversion efficiency is almost equivalent when titanium oxide is used as the material of the metal oxide semiconductor, and when zinc oxide is used, It became high. That is, if the dye 14 contains a compound in which at least one of the group consisting of R1, R2, R3 and R4 shown in Chemical Formula 1 is a carboxylic acid group having an alkyl chain, high conversion efficiency can be obtained. Was confirmed.

  Further, when focusing on n shown in Chemical formula 1, the conversion efficiency is a metal oxide semiconductor material in Examples 2 to 4 including the compounds shown in Chemical formulas 2 (2) to (4) where n = 1. Example 1 containing the compound shown in Chemical Formula 2 (1) where n = 0, and having the compound shown in Chemical Formula 3 (2) where n = 2 and It became higher than Example 7 containing the compound shown in Chemical formula 3 (3) where n = 3. That is, the range of n shown in Chemical Formula 1 in which sufficient conversion efficiency is obtained is 0 or more and 3 or less, and it was confirmed that excellent conversion efficiency can be obtained when n = 1.

  Furthermore, when focusing on the material of the metal oxide semiconductor, in Examples 1 to 7, the conversion efficiency was higher when zinc oxide was used than when titanium oxide was used.

  From this, it was confirmed that the conversion efficiency can be improved in the dye-sensitized solar cell in which the dye 14 includes the compound shown in Chemical Formula 1. In addition, when the dye 14 includes a compound in which the anchor group shown in Chemical Formula 1 is a carboxylic acid group or a compound in which the anchor group-containing group is a carboxylic acid group having an alkyl chain, higher conversion efficiency can be obtained. It was confirmed that it was obtained. Furthermore, as a material for the metal oxide semiconductor, high conversion efficiency can be obtained if it contains at least one of titanium oxide and zinc oxide, and in particular, higher conversion efficiency can be obtained by including zinc oxide. It was confirmed.

  The present invention has been described with reference to the embodiments and examples. However, the present invention is not limited to the embodiments described in the above embodiments and examples, and various modifications can be made. For example, the usage application of the photoelectric conversion element of the present invention is not necessarily limited to the usage already described, and may be other usages. Other applications include, for example, an optical sensor.

It is sectional drawing showing the structure of the photoelectric conversion element which concerns on one embodiment of this invention. It is sectional drawing which extracts and expands and shows the principal part of the photoelectric conversion element shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Working electrode, 11, 21 ... Conductive substrate, 11A ... Substrate, 11B ... Conductive layer, 12 ... Metal oxide semiconductor layer, 12A ... Dense layer, 12B ... Porous layer, 14 ... Dye, 20 ... Counter electrode, 22 ... conductive layer, 30 ... electrolyte-containing body.

Claims (5)

A photoelectric conversion element comprising an electrode having a dye and a carrier carrying the dye,
The said pigment | dye contains the compound represented by Chemical formula 1. The photoelectric conversion element characterized by the above-mentioned.

(The R1, R2, R3 and R4 Ri groups der having an alkyl group, an anchor group, or an anchor group, and R5 and R6 is an alkyl or alkenyl group. However, the group consisting of R1, R2, R3 and R4 at least one of the out is a group having an anchor group or anchor group, .R7, R8 and R9 are hydrogen atom. ring a and ring B are a benzene ring, with a benzene ring having a naphthalene ring or a halogen group, N is an integer of 0 or more.) 2. The photoelectric conversion device according to claim 1, wherein at least one of R 5 and R 6 shown in Chemical Formula 1 is an alkyl group or an alkenyl group . The anchor group includes a carboxylic acid group (—COOH), a phosphoric acid group (—PO ₃ H ₂ , —PO ₄ H ₂ ), a sulfonic acid group (—SO ₃ H), or a boric acid group (—B (OH) _2. The photoelectric conversion element according to claim 1 or 2, wherein Group having an anchor group, Ri carboxylic acid der having an alkyl _{chain, - (CH 2) m -COOH} (m is 1 or more is an integer.) Claim 1, characterized by being represented by The photoelectric conversion element of any one of Claim 3 thru | or 3. The photoelectric conversion element according to any one of claims 1 to 4, wherein the carrier includes at least one of zinc oxide and titanium oxide.

Images