JP5458406B2 - ORGANIC DYE COMPOUND AND SEMICONDUCTOR THIN FILM ELECTRODE, PHOTOELECTRIC CONVERSION ELEMENT, PHOTOELECTROCHEMICAL SOLAR CELL - Google Patents

Description

  The present invention relates to a technology of a dye-sensitized solar cell that uses photoelectrochemistry as a mechanism, and particularly to an organic dye that is used for a semiconductor thin film electrode of the solar cell.

In view of recent energy problems and environmental problems, the use of renewable energy instead of fossil fuels is expected, and solar power generation technology is particularly attracting attention. For large-scale power generation, research and development related to solar cells using inorganic semiconductors, as represented by silicon, is thriving, but research and development of organic solar cells have also advanced at the same time due to cost reductions and resource issues. It is out. Organic solar cells include organic thin-film solar cells that use organic compounds as semiconductors and dye-sensitized solar cells that use photoelectrochemistry as a mechanism.
Of the dyes that are the heart of dye-sensitized solar cells, ruthenium complex dyes that use rare metals are generally used at present, but they are rare metals, although they have excellent photoelectric conversion efficiency and durability. Therefore, there is a question about the stable supply of dyes for practical use of dye-sensitized solar cells. For metal-free organic dyes that do not use any rare metals, various organic dye compounds have been developed in the last 10 years, and their performance has improved dramatically, but the photoelectric conversion efficiency and durability are ruthenium dyes. The current situation is less than that. Among them, organic pigments that are considered promising are carbazole organic pigments (Patent Document 1, Non-Patent Document 1, Non-Patent Document 2) and indoline organic pigments (commercially available from Mitsubishi Paper Industries Co., Ltd., Chemicrea Co., Ltd.): Product name D149 (Patent Document 2).
Recently, a flexible dye-sensitized solar cell using a plastic substrate instead of a glass substrate has been developed. The titanium oxide semiconductor electrode used for it cannot pass through the process of baking from 450 ° C. to 500 ° C. when producing a titanium oxide semiconductor electrode used in a normal glass substrate, and it is at a relatively low temperature of 100 ° C. to 150 ° C. Titanium oxide materials that need to be fired and that can be fired sufficiently at a relatively low temperature for plastic substrates have been developed. (Patent Document 3, Patent Document 4, Non-Patent Document 3, Non-Patent Document 4) Accordingly, the development of a dye suitable for such a titanium oxide material for plastic solar cells is awaited.

PCT / JP2007 / 056383 Japanese Patent No.4326272 Published 2005-056627 (2005/03/03) Published 2006-076855 (2006/03/23)

J. Am. Chem. Soc., 128, 14256-14257 (2006) J. Mater. Chem., 19, 4829-4836 (2009) Chem. Lett., 36, 190-191 (2007). Electrochem. Soc., 154, A455-A461 (2007).

  Conventionally, a dye used for a flexible dye-sensitized solar cell using a plastic substrate is a ruthenium complex dye, and there is no organic dye comparable to this performance. If useful organic dyes are developed, research and development of flexible dye-sensitized solar cells will be accelerated, and it will be closer to practical use. The present invention newly develops a new organic dye having a basic skeleton of an organic dye such as a carbazole type and having good compatibility with low-temperature-fired titanium oxide, and uses it as an organic dye for a plastic substrate semiconductor thin film electrode Thus, it is an object to improve solar cell characteristics as compared with the case of using a ruthenium complex dye.

  As a result of intensive studies to solve the above problems, the present inventors have obtained an organic compound having a basic skeleton of an organic dye and having a carboxylic acid group having an amide bond as an adsorbing group bonded to an inorganic oxide semiconductor. Developed a glass substrate or plastic substrate semiconductor thin film electrode using the organic compound as an organic dye, a photoelectric conversion element using the electrode, and a photoelectrochemical solar cell using the element, and its solar energy conversion characteristics As a result of evaluation, it was found that the above problems could be solved, and the present invention was completed.

（式中、Ａは電子供与性を持つ炭素環又は複素環、Ｌはチオフェン環、フラン環、ピロール環もしくはこれらが縮環した複素環の中から選ばれる少なくとも1種の複素環を含む電子伝達性連結基、Ｒは電子伝達性連結基に結合している置換基、Ｒ_１およびＲ_２はアミド基とカルボキシル基との連結アルキレン基に結合している水素原子もしくは置換基、Ｍは水素原子又は塩形成陽イオンを示す。ｎは１〜６、ｍは１〜３の整数を示す。）
〈２〉〈１〉に記載の有機化合物からなることを特徴とする有機色素。
〈３〉〈２〉に記載の有機色素として用いることを特徴とする半導体薄膜電極。
〈４〉〈３〉に記載の半導体薄膜電極を用いることを特徴とする光電変換素子。
〈５〉〈４〉に記載の光電変換素子を用いることを特徴とする光電気化学太陽電池。 That is, according to this application, the following invention is provided.
<1> An organic compound represented by the following general formula (1).

(Wherein A is an electron-donating carbocyclic or heterocyclic ring, L is a thiophene ring, a furan ring, a pyrrole ring or an electron transfer containing at least one heterocyclic ring selected from these condensed heterocyclic rings) A linking group, R is a substituent bonded to the electron transfer linking group, R ₁ and R ₂ are a hydrogen atom or substituent bonded to a linking alkylene group of an amide group and a carboxyl group, and M is a hydrogen atom. Or a salt-forming cation, n is 1 to 6, and m is an integer of 1 to 3.)
<2> An organic dye comprising the organic compound according to <1>.
<3> A semiconductor thin film electrode, which is used as the organic dye according to <2>.
<4> A photoelectric conversion element using the semiconductor thin film electrode according to <3>.
<5> A photoelectrochemical solar cell using the photoelectric conversion element according to <4>.

  When the organic compound according to the present invention is used as an organic dye for a photoelectric conversion element, the photoelectric conversion efficiency can be improved as compared with the case of using an organic dye having a conventional cyanoacrylic acid-type adsorbing group. In particular, the effect is remarkable in a flexible dye-sensitized solar cell using a plastic substrate, and an efficiency exceeding the photoelectric conversion efficiency when a conventional ruthenium complex dye is used is observed. Specifically, in the conventional type, the electron transfer path of the dye molecule is directly bonded to the surface of the inorganic oxide semiconductor, so that when the electrons injected into the inorganic oxide semiconductor diffuse into the oxide semiconductor, the dye cation side However, in the present invention, the electron transfer path is an adsorbing group that binds to the inorganic oxide semiconductor through a linking group having no electron transfer property. Since it is separated from the carboxyl group, the re-reduction reaction of the dye cation is inhibited, and as a result, a high open circuit voltage is realized. In flexible dye-sensitized solar cells using plastic substrates, the efficiency of electron injection into externally fired inorganic oxide semiconductors and the external quantum efficiency are improved, and the short-circuit current is higher than that of conventional dyes, including ruthenium complex dyes. As a result, the photoelectric conversion element is included as a constituent element. The performance of the photoelectrochemical solar cell can be greatly enhanced.

An example of the block diagram of the photoelectrochemical solar cell of this invention is shown.

  In the general formula (1), A represents a carbocyclic or heterocyclic ring having an electron donating property. In this case, it can be a ring structure derived from various conventionally known carbocycles or heterocycles. The ring structure includes monocyclic and polycyclic rings, and in the case of polycyclic rings, condensed polycyclic rings and polycyclic rings are included. In the monocyclic ring, the number of ring constituent elements is 4 to 8, preferably 5 to 6. In the condensed polycycle, the number of single-ring bonds is 2 to 6, preferably 2 to 4. The carbocycle includes an aromatic carbocycle and an aliphatic carbocycle. The heterocyclic ring includes an aromatic heterocyclic ring and an aliphatic heterocyclic ring. The heterocyclic ring is a cyclic compound containing one or more (2 to 5) heteroatoms such as sulfur, oxygen, nitrogen and selenium as constituent elements. When two or more heteroatoms are included in the ring, the heteroatoms may be the same or different. Furthermore, the heterocyclic ring may be condensed with a benzene ring, a carbocyclic ring such as a naphthalene ring, or another heterocyclic ring.

  The following can be illustrated as a specific example of A. Examples of the aromatic carbocycle include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring. Examples of the aliphatic carbocycle include a cyclobutene ring, a cyclobutane ring, a cyclopentene ring, a cyclopentane ring, a cyclohexene ring, and a cyclohexane ring. As aromatic heterocycles, pyridine ring, quinoxaline ring, purine ring, oxazole ring, benzoxazole ring, naphthoxazole ring, thiazole ring, benzothiazole ring, naphthoxazole ring, selenazole ring, benzoselenazole ring, naphthoselenazole ring, Examples of aliphatic heterocycles such as imidazole ring, benzimidazole ring, naphthimidazole ring, quinoline ring, acridine ring, pyrazoline ring, pyrrolidine ring, piperidine ring, indoline ring, pyran ring, imidazolidine ring, thiazoline ring, imidazoline ring, oxazoline A ring etc. are mentioned. In A, the existing structural isomers are not limited, and various structural isomers can be used.

One or more substituents may be bonded to the ring A. Examples of such a substituent include linear alkyl groups such as a methyl group and hexyl group or branched alkyl groups having 1 to 20 carbon atoms such as an isobutyl group and 2-ethyloctyl group, preferably 1 to 12; methoxy An alkoxy group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms such as a butoxy group; an aryl group having 3 to 20 carbon atoms, preferably 5 to 12 carbon atoms such as a phenyl group or a naphthyl group; a methylamino group or an octylamino group A dialkylamino group having an alkyl group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms such as a monoalkylamino group having 1 to 12 carbon atoms, preferably 1 to 12 alkyl groups, and a diethylamino group, such as a piperidyl group A cyclic amino group having 5 to 8, preferably 5 to 6 ring constituent elements; a halogen group such as a chloro group, a bromo group or an iodo group; a hydroxyl group; a nitro group; Roh group, and the like.
Among the above A, from the viewpoint of an organic dye compound used as a sensitizing dye of a dye-sensitized solar cell, a carbazole ring, an indole ring, a thienoindole ring, and an indoline ring are preferable, and a carbazole ring is particularly preferable.

In the general formula (1), L represents an electron transfer linking group. In this case, the electron transfer linking group means a linking group having a function of transferring electrons on one side of the linking group to the other side, and such a linking group is well known in the art. . This linking group includes those having a structure containing at least one heterocyclic ring selected from a thiophene ring, a furan ring, a pyrrole ring, or a heterocyclic ring condensed with these.
In General formula (1), n shows 1-6, Preferably the integer of 2-4 is shown. In the number (n) of electron transporting linking groups, it is preferable that the organic dye compound used in the dye-sensitized solar cell has an absorption wavelength band that absorbs long wavelength light more efficiently. In addition, when the number is 7 or more, synthesis is further complicated and no significant improvement in photoelectric conversion characteristics is observed.

  Specific examples of the electron-transporting linking group containing a heterocyclic ring are as follows.

式中、ｎは１〜１２、好ましくは１〜８の整数を示す。Ｒ_３とＲ_４は、水素原子または置換基を示す。このような置換基の例として、メチル基、ヘキシル基などの直鎖型又はイソブチル基、２−エチルオクチル基などの分岐型の炭素数１〜２０、好ましくは１〜１２のアルキル基；メトキシ基、ブトキシ基などの炭素数１〜２０、好ましくは１〜１２アルコキシ基；フェニル基、ナフチル基などの炭素数３〜２０、好ましくは５〜１２のアリール基；メチルアミノ基、オクチルアミノ基などの炭素数１〜２０、好ましくは１〜１２のアルキル基を有するモノアルキルアミノ基、ジエチルアミノ基などの炭素数１〜２０、好ましくは１〜１２のアルキル基を有するジアルキルアミノ基；ピペリジル基などの環構成元素数５〜８、好ましくは５〜６の環状アミノ基；クロロ基、ブロモ基、ヨード基などのハロゲン基；水酸基；シアノ基；ニトロ基；アミノ基が含有される。 (1) A linking group containing a thiophene ring As this linking group, one represented by the following general formula (2) can be shown.

In the formula, n represents an integer of 1 to 12, preferably 1 to 8. R ₃ and R ₄ represent a hydrogen atom or a substituent. Examples of such substituents include linear alkyl groups such as methyl and hexyl groups or branched alkyl groups having 1 to 20, preferably 1 to 12, carbon atoms such as isobutyl and 2-ethyloctyl groups; methoxy groups An aryl group having 1 to 20 carbon atoms, such as a butoxy group, preferably 1 to 12 carbon atoms; an aryl group having 3 to 20 carbon atoms such as a phenyl group or a naphthyl group, preferably 5 to 12; a methylamino group or an octylamino group A dialkylamino group having an alkyl group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms such as a monoalkylamino group having 1 to 12 carbon atoms, preferably 1 to 12 alkyl groups, and a diethylamino group; a ring such as a piperidyl group Cyclic amino group having 5 to 8, preferably 5 to 6 constituent elements; halogen group such as chloro group, bromo group and iodo group; hydroxyl group; cyano group; nitro group; Amino groups are contained.

式中、ｎ、Ｒ_３、Ｒ_４は、前記と同じ。 (2) Linking group containing a furan ring Examples of the connecting group include those represented by the following general formula (3).

In the formula, n, R ₃ and R ₄ are the same as described above.

式中、ｎ、Ｒ_３、Ｒ_４は、前記と同じ。Ｘは水素原子又は置換基を有していてもよい炭化水素基を示す。この場合の炭化水素基には、脂肪族炭化水素基及び芳香族炭化水素基が含有される。脂肪族炭化水素基において、炭素数１〜１２、好ましくは１〜８のアルキル基、炭素数３〜１２、好ましくは４〜８のシクロアルキル基、炭素数２〜１２、好ましくは２〜８のアルケニル基、炭素数３〜１２、好ましくは４〜８にシクロアルケニル基が含有される。芳香族炭化水素基においては、その炭素数は６〜１８、好ましくは６〜１２である。芳香族炭化水素基には、炭素数６〜１８、好ましくは６〜１２のアリール基及び炭素数７〜１８、好ましくは７〜１２のアリールアルキル基が含有される。 (3) Linking group containing a pyrrole ring Examples of the connecting group include those represented by the following general formula (4).

In the formula, n, R ₃ and R ₄ are the same as described above. X represents a hydrogen atom or a hydrocarbon group which may have a substituent. In this case, the hydrocarbon group includes an aliphatic hydrocarbon group and an aromatic hydrocarbon group. In the aliphatic hydrocarbon group, an alkyl group having 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, preferably 4 to 8 carbon atoms, and 2 to 12 carbon atoms, preferably 2 to 8 carbon atoms. An alkenyl group, a cycloalkenyl group containing 3 to 12 carbon atoms, preferably 4 to 8 carbon atoms. In an aromatic hydrocarbon group, the carbon number is 6-18, Preferably it is 6-12. The aromatic hydrocarbon group contains an aryl group having 6 to 18 carbon atoms, preferably 6 to 12 carbon atoms, and an arylalkyl group having 7 to 18 carbon atoms, preferably 7 to 12 carbon atoms.

  As L, all of the above-described linking groups can be used, but from the viewpoint of facilitating the flow of electrons from the A ring to the cyanoacrylamide moiety which is the opposite electron-withdrawing group, it is represented by the general formula (2). The thiophene ring is preferably used.

In the above general formula (1), the amide bond is linked by a carboxyl group and an alkylene group — (CR ₁ R ₂ ) _m —, and m is an integer of 1 to 3, preferably 1 or 2. When m is 1 or more, electrons injected from the excited dye into titanium oxide are prevented from recombining with the dye cation, which contributes to the improvement of the open-circuit voltage. Since the site | part and the titanium oxide layer are too far apart, there exists a possibility that the electron injection from the excited pigment | dye to titanium oxide may not occur. R ₁ and R ₂ represent a hydrogen atom or a substituent. Examples of such substituents include linear alkyl groups such as methyl and hexyl groups or branched alkyl groups having 1 to 20, preferably 1 to 12, carbon atoms such as isobutyl and 2-ethyloctyl groups; methoxy groups An aryl group having 1 to 20 carbon atoms, such as a butoxy group, preferably 1 to 12 carbon atoms; an aryl group having 3 to 20 carbon atoms such as a phenyl group or a naphthyl group, preferably 5 to 12; a methylamino group or an octylamino group A dialkylamino group having an alkyl group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms such as a monoalkylamino group having 1 to 12 carbon atoms, preferably 1 to 12 alkyl groups, and a diethylamino group; a ring such as a piperidyl group Cyclic amino group having 5 to 8, preferably 5 to 6 constituent elements; halogen group such as chloro group, bromo group and iodo group; hydroxyl group; cyano group; nitro group; Amino groups are contained.

In the general formula (1), M represents a hydrogen atom or a salt-forming cation. The salt-forming cations in this case include alkali cations such as lithium, sodium and potassium, alkaline earth metals such as calcium and magnesium, cations derived from other metals, ammonium cations, and organic compounds derived from amines. An ammonium cation and the like are contained.
Next, specific examples of the compound (organic dye) represented by the general formula (1) are shown below, but the present invention is not limited to these compounds.

  The method for synthesizing the compound represented by the general formula (1) according to the present invention is not particularly limited. For example, the compound can be synthesized by the following method. The detailed synthesis method is slightly different depending on each dye molecule, but basically, the synthesis is performed by a three-step route. First, as a first step, a Suzuki ring containing a heterocyclic ring corresponding to A to which an iodine atom or a bromine atom is bonded, and a boric acid ester derivative of an electron transfer linking group such as a thiophene ring or a furan ring corresponding to L, which are separately synthesized, are used. Bond by ring reaction. As a second step, by causing a Vilsmeier reagent to act on an intermediate in which A and L are bonded, a side opposite to the side bonded to the A heterocycle of an electron transfer linking group L such as a thiophene ring or a furan ring is provided. Introduce aldehyde. In the third step, when the aldehyde derivative and a separately synthesized cyanoacetic acid derivative are reacted in the presence of a base such as piperidine, a corresponding organic dye compound is obtained. Regarding the first stage and the second stage, the conventional method already described in non-patent literature (J. Am. Chem. Soc., 128, 14256 (2006) or Chem. Mater 21, 3993 (2008)) Can do. In addition, the synthesis in the third stage can be performed specifically by the method as described in Examples 3 to 8. The cyanoacetic acid derivative can be produced by a known method. For example, the cyanoacetic acid derivative is synthesized by a condensation reaction of cyanoacetic acid and an amino acid ester, which are commercially available raw materials, followed by a deprotection reaction.

The organic compound represented by the general formula (1) according to the present invention can be effectively used as an organic dye for forming a semiconductor thin film electrode.
In this case, a conventionally known substrate can be applied as it is as the substrate of the semiconductor thin film electrode. For example, a glass or plastic substrate coated with a conductive transparent oxide semiconductor thin film such as fluorine or antimony-doped tin oxide (NESA), tin-doped indium oxide (ITO), or aluminum-doped zinc oxide. Alternatively, an opaque conductive substrate made of a metal foil containing 60% by mass or more of a metal selected from the group consisting of iron, aluminum, and titanium can be used. Preferred is a fluorine-doped tin oxide thin film coated glass. When an opaque conductive substrate made of a metal foil is used for the semiconductor thin film electrode substrate, a light transmissive substrate is used as the counter electrode.

The semiconductor thin film electrode according to the present invention is preferably in the form of compound semiconductor nanoparticles and a nanoporous structure.
Compound semiconductor materials include, for example, TiO ₂ , ZnO, In ₂ O ₃ , SnO ₂ , ZrO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , Fe ₂ O ₃ , Ga ₂ O ₃ , WO ₃ , SrTiO _3, etc. metal oxides and complex oxides, AgI, AgBr, CuI, metal halides such as CuBr, _{further, ZnS, TiS 2, ZnO,} in 2 S 3, SnS, SnS 2, ZrS 2, Ag 2 S, PbS, CdS , TaS ₂ , CuS, Cu ₂ S, WS ₂ , MoS _2, CuInS ₂ and other metal sulfides, CdSe, TiSe ₂ , ZrSe ₂ , Bi ₂ Se ₃ , In ₂ Se ₃ , SnSe, SnSe ₂ , Ag ₂ Se , TaSe ₂ , CuSe, Cu ₂ Se, WSe ₂ , MoSe ₂ , CuInSe ₂ , CdTe, TiTe ₂ , ZrTe ₂ , Bi ₂ Te ₃ , In ₂ Te ₃ , SnTe, SnTe ₂ , Ag ₂ Te, TaTe ₂ , CuTe Examples thereof include, but are not limited to, metal selenides such as Cu ₂ Te, WTe ₂ and MoTe ₂ and metal tellurides. An oxide semiconductor material such as TiO ₂ , ZnO, SnO ₂ is preferable.

  For example, commercially available titanium oxide particles such as P25 (Degussa or Nippon Aerosil), ST-01 (Ishihara Sangyo), SP-210 (Showa Denko) may be used, or J. Am. Ceram. Soc. 80, 3157 (1997), crystalline titanium oxide particles obtained by hydrolysis, autoclaving, etc. from titanium alkoxide by a sol-gel method may be used. Titanium oxide particles obtained from a titanium alkoxide by a sol-gel method are preferred.

  The particle diameter of the semiconductor nanoparticles constituting the semiconductor thin film is 5 to 1000 nm, preferably 10 to 300 nm.

For example, a method for manufacturing a semiconductor thin film electrode using an oxide semiconductor includes the following methods, but is not limited thereto. Oxide semiconductor nanoparticles are mixed well with water, a polymer such as polyethylene glycol, a surfactant, and the like to form a slurry, which is applied onto a substrate by a method called a doctor blade method. Alternatively, a polymer as a binder and a highly viscous organic solvent may be mixed and applied to the substrate by a screen printing method. An oxide semiconductor thin film electrode can be obtained by baking the substrate coated with the oxide semiconductor at 450 to 500 ° C. in air or oxygen.
The film thickness of the semiconductor thin film electrode is usually 0.5 to 100 μm, preferably 5 to 20 μm.

  Adsorption of the organic dye sensitizer onto the surface of the semiconductor electrode is performed by immersing the semiconductor thin film electrode in a dye solution and allowing it to stand at room temperature for 1 hour or more, or for 10 minutes to 1 hour under heating conditions. Preferably, the method is left at room temperature for 6 hours or more.

  The solvent for the dye adsorption is methanol, ethanol, or n-propanol. Alcohol solvents such as isopropanol, n-butanol, t-butanol, organic solvents such as chloroform, acetone, acetonitrile, tetrahydrofuran, dimethyl sulfoxide, dimethylformamide, benzene, toluene, xylene, chlorobenzene, dichlorobenzene, and mixed solvents thereof is there. Preferred is a mixed solvent of ethanol, chloroform, and t-butanol-acetonitrile.

  The dye concentration of the dye solution is usually 0.05 to 0.5 mM, preferably 0.2 to 0.3 mM.

  When the dye is adsorbed, a call such as cholic acid, deoxycholic acid, chenodeoxycholic acid, taurochenodeoxycholic acid is used in order to prevent association between the dyes on the semiconductor electrode and to cause an electron transfer reaction from the dye to the semiconductor efficiently. An acid derivative, its sodium salt, a surfactant such as Triton X, and glucose may be dissolved in the dye solution and co-adsorbed with the dye. The concentration of the coadsorbent in the dye solution is usually 1 to 100 mM, preferably 5 to 20 mM.

The electrolyte solution used for the photoelectric conversion element and the photoelectrochemical solar cell of the present invention includes a redox ion pair. Redox ion pairs are I ⁻ / I ₃ ⁻ , Br ⁻ / Br ₂ , Fe ²⁺ / Fe ³⁺ , Sn ²⁺ / Sn ⁴⁺ , Cr ²⁺ / Cr ³⁺ , V ²⁺ / V ³⁺ , Examples thereof include, but are not limited to, S ²⁻ / S ₂ ⁻ , anthraquinone, and ferrocene. As an electrolyte, in the case of iodine redox, imidazolium derivatives containing these ions (methylpropyl imidazolium iodide, methyl butyl imidazolium iodide, iodide, ethyl methyl imidazolium, dimethylpropyl imidazolium iodide, etc.), In the case of lithium iodide, potassium iodide, tetraalkylammonium iodide and iodine, and bromine redox, a mixture of lithium bromide, potassium bromide, tetraalkylammonium bromide and bromine containing these ions is used. Preferred are lithium iodide, tetraalkylammonium and imidazolium iodide derivatives of iodine redox.

  The concentration of the redox electrolyte is usually 0.02 to 1 M, preferably 0.03 to 0.5 M.

  Solvents used in the redox electrolyte include alcohol solvents such as methanol, ethanol and isopropanol, nitrile solvents such as acetonitrile, methoxyacetonitrile, propionitrile and methoxypropionitrile, carbonate solvents such as ethylene carbonate and propylene carbonate, dimethyl An organic solvent such as sulfoxide, dimethylformamide, tetrahydrofuran, nitromethane, n-methylpyrrolidone, or a mixed solvent thereof.

  The redox electrolyte used in the photoelectric conversion element and the photoelectrochemical solar cell of the present invention has t-butyl as shown in J. Am. Chem. Soc., 115, 6382 (1993), etc., for the purpose of improving photoelectric conversion characteristics. Basic additives such as pyridine derivatives such as pyridine may be added. The concentration of the additive in the electrolyte at that time is usually 0.05 to 1 M, preferably 0.1 to 0.5 M.

  Instead of the redox electrolyte using the solvent, 1-ethyl-3-methylimidazolium iodide, 1-n-propyl-3-methylimidazolium iodide, 1-n-butyl iodide, which does not contain a solvent, are used. Mixtures of iodide and iodine of imidazolium derivatives that are room temperature molten salts (ionic liquids) such as 3-methylimidazolium and 1-n-hexyl-3-methylimidazolium iodide may be used as the electrolyte ( For example, Chem. Commun., 374 (2002), J. Phys. Chem. B, 107, 4374 (2003)).

  When using the room temperature molten salt electrolyte as described above, the electrolyte may be pseudo-solidified using various gelling agents used in Chem. Commun., 374 (2002).

  Instead of the redox electrolyte used in the photoelectric conversion element and the photoelectrochemical solar cell of the present invention, inorganic materials such as CuI, CuBr, and CuSCN used in J. Photochem. Photobiol. A: Chem., 117, 137 (1998), etc. p-type semiconductor hole transport materials or organic low-molecular or organic compounds such as spiropyran derivatives (Natrure, 395, 583 (1998)), polypyrrole derivatives (Sol. Energy Mater. Sol. Cells, 55, 113 (1998)), polythiophene A polymer hole transport material may be used.

  The counter electrode used for the photoelectric conversion element and the photoelectrochemical solar cell of the present invention is a metal foil containing 60% by mass or more of a metal selected from the group consisting of iron, aluminum and titanium on a transparent conductive oxide-coated glass or plastic substrate. A substrate on which a noble metal such as Pt, Rh, or Ru, or carbon, an oxide semiconductor, an organic polymer material, or the like is coated in a thin film is used, but is not limited thereto. Pt or a carbon electrode is preferable. When an opaque substrate is used as the counter electrode, a conductive transparent substrate is used as the semiconductor thin film electrode substrate.

The spacer used in the photoelectric conversion element and the photoelectrochemical solar cell of the present invention is a polymer film such as polyethylene, polypropylene, ethylene vinyl acetate, heat or a thermoplastic resin, and the film thickness is usually 15 to 120 μm. Yes, preferably 15-30 μm.
FIG. 1 shows an example of the structure of a photoelectrochemical solar cell produced as described above. In FIG. 1, 1 is a platinum sputtered conductive glass or plastic, 2 is a redox electrolyte layer, 3 is a sealant, 4 is a dye-adsorbing semiconductor thin film electrode, and 5 is a conductive transparent glass or plastic. Note that the photoelectrochemical solar cell produced in Example 11 also had this structure.

  The invention will now be described by way of examples. The compounds (21) to (31) are specifically shown in the following description. In the following examples, the compounds represented by the formulas are shown with the respective formula numbers as appropriate.

Example 1 (Synthesis of Compound No (24))
Glycine tertiary butyl ester hydrochloride (22) 500 mg, triethylamine 0.4 mL, cyanoacetic acid (21) 240 mg, and 1-hydroxybenzotriazole 500 mg were dissolved in N, N-dimethylformamide 10 mL. The solution was then cooled to 0 ° C. and 630 mg of dicyclohexylcarbodiimide was added. The reaction solution is stirred at 0 ° C. for 1 hour and then at room temperature overnight. To the reaction solution after stirring overnight, 20 mL of water and 20 mL of ethyl acetate were added, the precipitated insoluble matter was filtered, and the organic layer was washed three times with a 10% aqueous sodium bicarbonate solution, then with water and saturated brine, Dried with magnesium sulfate. The solvent was distilled off under reduced pressure, and the resulting crude product was purified by column chromatography (silica gel: hexane / ethyl acetate = 1/1), and the ester derivative of the target compound represented by (23) was white. 500 mg was obtained as a powder. The yield was 85%.
¹ H NMR data (400 MHz, CDCl ₃ ) of the ester derivative (23): δ 6.92 (1H, t, J = 4.8 Hz), 3.97 (2H, d, J = 4.8 Hz), 3.49 (2H, s), 1.48 (9H, s); ¹³ C NMR data (100 MHz, CDCl ₃ ): δ 167.2, 160.5, 113.5, 81.8, 41.4, 26.9, 24.7.

500 mg of the ester derivative represented by (23) was dissolved in 15 mL of dichloromethane, and the reaction solution was cooled to 0 ° C. Thereto was added dropwise 15 mL of trifluoroacetic acid, and the reaction solution was stirred at 0 ° C. for 1 hour and then at room temperature for 2 hours. After stirring, the solvent was distilled off under reduced pressure, and the resulting crude product was purified by column chromatography (silica gel: ethyl acetate), and the carboxylic acid derivative of the target compound represented by (24) was obtained as a white powder. 125 mg was obtained. The yield was 28%.
¹ H NMR data (400 MHz, THF-d ₈ ) of the carboxylic acid derivative (24): δ 7.72 (1H, t, J = 5.6 Hz), 3.95 (2H, d, J = 5.6 Hz), 3.51 (2H, s ); ¹³ C NMR data (100 MHz, THF-d ₈ ): δ 169.0, 160.8, 113.4, 39.6, 23.3.

Example 2 (Synthesis of Compound No (27))
Beta-alanine tertiary butyl ester hydrochloride (25) 1 g, triethylamine 0.8 mL, cyanoacetic acid (21) 468 mg, and 1-hydroxybenzotriazole 781 mg were dissolved in N, N-dimethylformamide 20 mL. The solution was then cooled to 0 ° C. and 1.34 g of dicyclohexylcarbodiimide was added. The reaction solution is stirred at 0 ° C. for 1 hour and then at room temperature overnight. To the reaction solution after stirring overnight, 20 mL of water and 20 mL of ethyl acetate were added, the precipitated insoluble matter was filtered, and the organic layer was washed three times with a 10% aqueous sodium bicarbonate solution, then with water and saturated brine, Dried with magnesium sulfate. The solvent was distilled off under reduced pressure, and the resulting crude product was purified by column chromatography (silica gel: hexane / ethyl acetate = 1/1), and the ester derivative of the target compound represented by (26) was white. As a powder, 1.04 g was obtained. The yield was 89%.
¹ H NMR data (400 MHz, CDCl ₃ ) of ester derivative (26): δ 7.24 (1H, t, J = 5.2 Hz), 3.43 (2H, q), 3.42 (2H, s), 2.41 (2H, t, J = 6.4 Hz), 1.37 (9H, s); ¹³ C NMR data (100 MHz, CDCl ₃ ): δ 170.2, 160.8, 113.9, 80.1, 34.7, 33.6, 26.9, 24.8.

1 g of the ester derivative represented by (26) was dissolved in 20 mL of dichloromethane, and the reaction solution was cooled to 0 ° C. 20 mL of trifluoroacetic acid was added dropwise thereto, and the reaction solution was stirred at 0 ° C. for 1 hour and then at room temperature for 2 hours. After stirring, the solvent was distilled off under reduced pressure, and the resulting crude product was purified by column chromatography (silica gel: ethyl acetate), and the target carboxylic acid derivative represented by (27) was obtained as a white powder. 355 mg was obtained. The yield was 48%.
¹ H NMR data of carboxylic acid derivative (27) (400 MHz, THF-d ₈ ): δ 7.79 (1H, t, J = 5.6 Hz), 3.50 (2H, s), 3.45 (2H, q), 2.51 (2H , t, J = 5.6); ¹³ C NMR data (100 MHz, THF-d ₈ ): δ 171.7, 161.3, 113.8, 34.5, 32.0, 23.8.

Example 3 (Synthesis of Compound No (8))
160 mg of the aldehyde represented by (28) and 100 mg of the carboxylic acid derivative represented by (24) are dissolved in a mixed solvent of 5 mL of acetonitrile and 2 mL of toluene, and the reaction solution is heated to reflux for 15 hours in the presence of 0.5 mL of piperidine. After cooling, the mixture was diluted with chloroform, and the chloroform layer was washed with 1M hydrochloric acid, water and saturated brine in that order, and dried over sodium sulfate. The solvent was distilled off under reduced pressure, and the resulting crude product was purified by column chromatography (silica gel: chloroform → chloroform / ethanol = 10/1 → chloroform / ethanol / acetic acid = 50/10/1). 75 mg of the dye compound (8) was obtained. The yield was 41%.
¹ H NMR data of dye compound (8) (400 MHz, THF-d ₈ ): δ 8.52 (1H, s), 8.42 (1H, d, J = 1.2 Hz), 8.19 (1H, d, J = 7.6 Hz) , 7.77 (1H, d, J = 7.6 Hz), 7.70 (1H, t, J = 5.6 Hz), 7.56-7.52 (2H, m), 7.46 (1H, t, J = 7.6 Hz), 7.36 (1H, s), 7.25 (1H, s), 7.23 (1H, t, J = 7.6 Hz), 7.15 (1H, s), 7.13 (1H, s), 4.47 (2H, q, J = 7.2 Hz), 4.07 ( 2H, d, J = 5.6 Hz), 2.96-2.86 (8H, m), 1.85-1.67 (8H, m), 1.56-1.33 (27H, m), 0.98-0.93 (12H, m).

Example 4 (Synthesis of Compound No (9))
350 mg of the aldehyde represented by (28) and 250 mg of the carboxylic acid derivative represented by (27) are dissolved in a mixed solvent of 3 mL of acetonitrile and 3 mL of toluene, and the reaction solution is heated to reflux for 15 hours in the presence of 0.5 mL of piperidine. After cooling, the mixture was diluted with chloroform, and the chloroform layer was washed with 1M hydrochloric acid, water and saturated brine in that order, and dried over sodium sulfate. The solvent was distilled off under reduced pressure, and the resulting crude product was purified by column chromatography (silica gel: chloroform → chloroform / ethanol = 10/1 → chloroform / ethanol / acetic acid = 50/10/1). 158 mg of the dye compound (9) was obtained. The yield was 39%.
¹ H NMR data (400 MHz, THF-d ₈ ) of the dye compound (9): 8.51 (1H, s), 8.43 (1H, d, J = 1.2 Hz), 8.19 (1H, d, J = 7.6 Hz), 7.76 (1H, d, J = 7.6 Hz), 7.60 (1H, t, J = 5.6 Hz), 7.51 (2H, d, J = 7.6 Hz), 7.46 (1H, t, J = 7.6 Hz), 7.35 ( 1H, s), 7.22 (1H, t, J = 7.6 Hz), 7.21 (1H, s), 7.13 (1H, s), 7.12 (1H, s), 4.44 (2H, q, J = 7.2 Hz), 3.64 (2H, q), 2.94-2.83 (8H, m), 2.63 (2H, t, J = 6.0 Hz), 1.84-1.65 (8H, m), 1.55-1.33 (27H, m), 0.99-0.93 ( 12H, m).

Example 5 (Synthesis of Compound No (10))
150 mg of the aldehyde represented by (29) and 80 mg of the carboxylic acid derivative represented by (24) are dissolved in a mixed solvent of 4 mL of acetonitrile and 2 mL of toluene, and the reaction solution is heated to reflux for 15 hours in the presence of 0.5 mL of piperidine. After cooling, the mixture was diluted with chloroform, and the chloroform layer was washed with 1M hydrochloric acid, water and saturated brine in that order, and dried over sodium sulfate. The solvent was distilled off under reduced pressure, and the resulting crude product was purified by column chromatography (silica gel: chloroform → chloroform / ethanol = 10/1) to obtain 106 mg of the target dye compound (10). The yield was 62%.
¹ H NMR data of dye compound (10) (400 MHz, THF-d ₈ ): δ 8.51 (1H, s), 8.50 (1H, d, J = 1.6 Hz), 8.43 (1H, d, J = 1.6 Hz) , 7.77 (1H, dd, J ₁ = 8.4 Hz, J ₂ = 1.6 Hz), 7.73 (1H, dd, J ₁ = 8.4 Hz, J ₂ = 1.6 Hz), 7.69 (2H, d, J = 8.8 Hz) , 7.66 (1H, t, J = 5.6 Hz), 7.54 (1H, d, J = 4.4 Hz), 7.52 (1H, d, J = 4.8 Hz), 7.38 (1H, s), 7.22 (1H, s) , 7.15 (1H, s), 7.02 (2H, d, J = 8.8 Hz), 4.46 (2H, q, J = 7.6 Hz), 4.09 (2H, d, J = 5.6 Hz), 4.04 (2H, t, J = 7.4 Hz), 2.95-2.83 (6H, m), 1.87-1.66 (8H, m), 1.59-1.35 (27H, m), 0.99-0.93 (12H, m).

Example 6 (Synthesis of Compound No (11))
300 mg of the aldehyde represented by (29) and 150 mg of the carboxylic acid derivative represented by (27) are dissolved in a mixed solvent of 5 mL of acetonitrile and 2 mL of toluene, and the reaction solution is heated to reflux for 15 hours in the presence of 0.5 mL of piperidine. After cooling, the mixture was diluted with chloroform, and the chloroform layer was washed with 1M hydrochloric acid, water and saturated brine in that order, and dried over sodium sulfate. The solvent was distilled off under reduced pressure, and the resulting crude product was purified by column chromatography (silica gel: chloroform → chloroform / ethanol = 10/1) to obtain 200 mg of the target dye compound (11). The yield was 58%.
¹ H NMR data of dye compound (11) (400 MHz, THF-d ₈ ): δ 8.50 (1H, s), 8.49 (1H, d, J = 1.6 Hz), 8.42 (1H, d, J = 1.6 Hz) , 7.76 (1H, dd, J ₁ = 8.4 Hz, J ₂ = 1.6 Hz), 7.71 (1H, dd, J ₁ = 8.4 Hz, J ₂ = 1.6 Hz), 7.69 (2H, d, J = 8.8 Hz) , 7.57 (1H, t, J = 5.6 Hz), 7.53 (1H, d, J = 3.6 Hz), 7.50 (1H, d, J = 3.2 Hz), 7.37 (1H, s), 7.20 (1H, s) , 7.13 (1H, s), 7.02 (2H, d, J = 8.8 Hz), 4.43 (2H, q, J = 7.2 Hz), 4.03 (2H, t, J = 6.4 Hz), 3.65 (2H, q) , 2.93-2.82 (6H, m), 2.62 (2H, t, J = 6.8 Hz), 1.86-1.65 (8H, m), 1.56-1.49 (6H, m), 1.45-1.36 (21H, m), 0.99 -0.93 (12H, m).

Example 7 (Synthesis of Compound No (12))
140 mg of the aldehyde represented by (30) and 48 mg of the carboxylic acid derivative represented by (24) are dissolved in a mixed solvent of 1 mL of acetonitrile and 2 mL of toluene, and the reaction solution is heated to reflux for 15 hours in the presence of 0.5 mL of piperidine. After cooling, the mixture was diluted with chloroform, and the chloroform layer was washed with 1M hydrochloric acid, water and saturated brine in that order, and dried over sodium sulfate. The solvent was distilled off under reduced pressure, and the resulting crude product was purified by column chromatography (silica gel: chloroform → chloroform / ethanol = 10/1 → chloroform / ethanol / acetic acid = 50/10/1). 77 mg of a dye compound (12) was obtained. The yield was 48%.
¹ H NMR data (400 MHz, THF-d ₈ ) of dye compound (12): δ 8.51 (1H, s), 8.50 (1H, d, J = 1.6 Hz), 8.43 (1H, d, J = 1.6 Hz) , 7.77 (1H, dd, J ₁ = 8.4 Hz, J ₂ = 1.6 Hz), 7.74-7.69 (3H, m), 7.66 (1H, t, J = 5.6 Hz), 7.55 (1H, d, J = 5.6 Hz), 7.52 (1H, d, J = 5.6 Hz), 7.38 (1H, s), 7.22 (1H, s), 7.14 (1H, s), 7.04 (2H, d, J = 8.8 Hz), 4.46 ( 2H, q, J = 7.2 Hz), 4.09 (2H, d, J = 5.6 Hz), 3.86 (3H, s), 2.95-2.83 (6H, m), 1.85-1.66 (6H, m), 1.59-1.36 (21H, m), 0.98-0.93 (9H, m).

Example 8 (Synthesis of Compound No (14))
140 mg of the aldehyde represented by (31) and 60 mg of the carboxylic acid derivative represented by (24) are dissolved in a mixed solvent of 2 mL of acetonitrile and 2 mL of toluene, and the reaction solution is heated to reflux for 15 hours in the presence of 0.5 mL of piperidine. After cooling, the mixture was diluted with chloroform, and the chloroform layer was washed with 1M hydrochloric acid, water and saturated brine in that order, and dried over sodium sulfate. The solvent was distilled off under reduced pressure, and the resulting crude product was purified by column chromatography (silica gel: chloroform → chloroform / ethanol = 10/1) to obtain 45 mg of the target dye compound (14). The yield was 27%.
¹ H NMR data of dye compound (14) (400 MHz, THF-d ₈ ): δ 8.51 (1H, s), 7.68 (1H, d, J = 7.6 Hz), 7.66 (1H, t, J = 5.6 Hz) , 7.48 (1H, d, J = 7.6 Hz), 7.44 (1H, s), 7.28-7.23 (3H, m), 7.14 (1H, s), 7.12 (1H, t, J = 7.6), 4.42 (2H , q, J = 7.2 Hz), 4.07 (2H, d, J = 5.6 Hz), 2.93 (2H, t, J = 8.0 Hz), 2.87 (4H, t, J = 7.6 Hz), 1.81-1.67 (6H , m), 1.56-1.36 (21H, m), 0.97-0.92 (9H, m).

Example 9
(1) Preparation of Organic Dye-Adsorbed Titanium Oxide Thin Film Glass Electrode Crystalline titanium oxide nanoparticles were obtained by autoclaving a titanium oxide colloid prepared by hydrolysis of titanium / tetraisopropoxide. An organic paste was prepared by mixing ethyl cellulose as a binder and α-terpineol as a solvent. Alternatively, a commercially available titanium oxide paste (for example, manufactured by Solaronix) may be used. The titanium oxide paste was applied onto tin oxide-coated conductive glass by screen printing and baked at 500 ° C. for 1 to 2 hours in air to obtain a titanium oxide thin film electrode having a thickness of 3 to 20 microns. By immersing this electrode in a 0.3 mM organic dye solution (the solvent is toluene, t-butyl alcohol: acetonitrile = 1: 1 in the ruthenium complex dye (36)) and leaving it at room temperature for 10 hours or more, An organic dye-adsorbed titanium oxide thin film electrode was obtained.

(2) Fabrication of organic dye-adsorbed titanium oxide thin film plastic electrode Titanium oxide paste PECC-C01-06 (manufactured by Pexel Technologies) for low-temperature film formation, ITO-PEN film (sheet resistance 13 ohm / □, film thickness 200 μm) It was coated on the top by a doctor blade method, dried at room temperature, and then heated and dried at 150 ° C. for 10 minutes. The thickness of the dried titanium oxide film was 6 μm. This electrode was immersed in a 0.3 mM organic dye solution (the solvent was toluene, and t-butyl alcohol: acetonitrile = 1: 1 in the ruthenium complex dye (36)), and left at 40 ° C. for 30 minutes, whereby organic A dye-adsorbed titanium oxide plastic electrode was obtained.

(3) Preparation of photoelectrochemical solar cell using glass electrode and evaluation of photoelectric conversion characteristics The dye described in Table 1 was adsorbed on the titanium oxide thin film electrode (film thickness: 6 microns) prepared in (1) above, and platinum was Sputtered tin oxide coated conductive glass is used as a counter electrode, and a polyethylene film spacer is sandwiched between them, and the electrolyte solution is 0.6 M 1,2-dimethyl-3-propylimidazolium iodide-0.1 M lithium iodide-0.05. An acetonitrile solution of M iodine-0.5 M t-butylpyridine was injected, and a stopper cell was prepared with a gem clip. The photoelectric conversion characteristics of the cell were measured using a solar simulator consisting of a xenon lamp and an AM filter as a light source, and the photocurrent voltage characteristics were measured using a source meter.

(4) Production of photoelectrochemical solar cell using plastic electrode and evaluation of photoelectric conversion characteristics The dye described in Table 1 was adsorbed to the titanium oxide plastic electrode (film thickness 5 microns) produced in (2) above, and platinum was Sputtered tin oxide coated conductive glass is used as a counter electrode, and an ionomer film (thickness: 25 microns) is sandwiched between them, and 0.4M tetrabutylammonium iodide-0.3M 1-methylbenzimidazole-0 as electrolyte is placed in the gap. .04M Iodine γ-Butyrolactone: Methoxypropionitrile = 1: 1 solution was injected, and a stop cell was prepared with a Zem clip. The photoelectric conversion characteristics of the cell were measured using a solar simulator composed of a xenon lamp and an AM filter as a light source, and the photocurrent voltage characteristics were measured using a source meter. The electrolytic solution composition used in this evaluation is an electrolytic solution having high durability of ITO-PEN in a photoelectrochemical solar cell using an ITO-PEN film. (For example, Solar Energy Materials & Solar Cells 93 (2009) 836-839.)

ここで、TBAはテトラブチルアンモニウムカチオンを示す。

Here, TBA represents a tetrabutylammonium cation.

  Table 1 shows a novel organic dye synthesized according to the present invention and a photosensitized glass electrode using a conventional organic dye (32)-(35) and ruthenium complex dye (36) whose acceptor site is cyanoacrylic acid as a comparative example. The photoelectric conversion characteristics of the used photoelectrochemical solar cell are shown. As shown in Table 1, the photoelectrochemical solar cell using the novel organic dye synthesized according to the present invention has a higher open-circuit voltage value than the conventional organic dye, and the ruthenium complex dye is used. The value equivalent to that of was shown. In conventional organic dyes, since the π-conjugated system is directly bonded to titanium oxide, it is considered that electrons injected into titanium oxide are likely to recombine back to the dye cation. However, the novel organic dye synthesized by the present invention Then, since the π conjugation in the dye molecule is not directly bonded to titanium oxide, recombination hardly occurs, which is considered to have led to an improvement in open circuit voltage. Concerning the short-circuit current density, on the contrary, the efficiency of electron injection into titanium oxide is reduced by the distance between the π-conjugated system and titanium oxide, and as a result, the short-circuit current density is lower than that of conventional organic dyes. As a result, the conversion efficiency shows the same value due to the improvement of the open circuit voltage and the decrease of the short circuit current density.

  Table 2 shows new organic dyes synthesized according to the present invention and, as a comparative example, photosensitized plastic electrodes using organic dyes (32)-(35) and ruthenium complex dyes (36) whose acceptor sites are conventional cyanoacrylic acid. The photoelectric conversion characteristics of the used photoelectrochemical solar cell are shown. In the organic dyes (9) and (11) of the present invention, all elements (short-circuit current density, open-circuit voltage, form factor) of the photoelectric conversion characteristics of solar cells using conventional organic dyes are improved, and further a ruthenium complex. Even when compared with the case of using the dye (36), a photoelectric conversion characteristic exceeding that was shown. In general, the efficiency of electron injection into a low-temperature-fired titanium oxide film used for plastic electrodes was much lower in both ruthenium complex dyes and organic dyes than in high-temperature fired titanium oxide used in glass electrodes. In the organic dye, the electron injection efficiency is improved, and as a result, a high short-circuit current density is realized. Regarding the open circuit voltage, it is considered that the photoelectrochemical solar cell using the photosensitized glass electrode has been improved for the above reason. Moreover, until now there has been no organic dye exceeding the photoelectric conversion characteristics of solar cells using a ruthenium complex dye in this system, but it has been proved that the present invention can provide it.

  The present invention provides a dye effective as the heart of a dye-sensitized solar cell. Dye-sensitized solar cells are expected to be used as consumer power supplies such as calculators and personal computers. One of the required technologies is flexibility, and the development and practical application of dye-sensitized solar cells using plastic substrates is expected. The present invention provides an organic compound as a dye particularly effective for a dye-sensitized solar cell using the plastic substrate.

DESCRIPTION OF SYMBOLS 1 Platinum sputtering conductive glass, plastic, or metal 2 Redox electrolyte layer 3 Sealant 4 Dye adsorption semiconductor thin film electrode 5 Conductive transparent glass, plastic, or metal

Claims (5)

An organic compound represented by the following general formula (1).

(Wherein A is an electron-donating carbocyclic or heterocyclic ring, L is a thiophene ring, a furan ring, a pyrrole ring or an electron transfer containing at least one heterocyclic ring selected from these condensed heterocyclic rings) A linking group, R is a substituent bonded to the electron transfer linking group, R ₁ and R ₂ are a hydrogen atom or substituent bonded to a linking alkylene group of an amide group and a carboxyl group, and M is a hydrogen atom. Or a salt-forming cation, n is 1 to 6, and m is an integer of 1 to 3.)   An organic dye comprising the organic compound according to claim 1.   A semiconductor thin film electrode, which is used as the organic dye according to claim 2.   A photoelectric conversion element using the semiconductor thin film electrode according to claim 3.   A photoelectrochemical solar cell using the photoelectric conversion element according to claim 4.

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