JP5996255B2 - Photoelectric conversion element and π-conjugated organic radical compound - Google Patents

Description

  The present invention relates to a photoelectric conversion element and a π-conjugated organic radical compound.

  With the advent of molecular nanoelectronic materials surpassing materials, elements, and devices composed of inorganic compounds, the function of organic compounds has attracted attention as the main role of electronic materials. Examples of organic devices using organic compounds as electronic materials include solar cells, organic electroluminescent elements, field effect transistors (FETs), and the like. These are devices utilizing the electrical and optical properties of organic compounds, and have made remarkable progress in recent years.

  Accompanying these developments, new technology development using organic radical compounds has come to be performed. Organic radical compounds exhibit unique electronic and magnetic properties derived from unpaired electrons, especially those with ferromagnetism, for example, specific gravity compared to lightweight magnets and inorganic magnetic fillers used in low-gravity space. Applications can be expected for magnetic coating materials with small size, recording materials that can increase the density of information, drug delivery system materials that can be controlled by external magnets, and so on. Moreover, since it has a heterocyclic structure similar to DNA base and further has radical oxidation ability, it can be expected to be applied to DNA interacting substances or DNA cleaving agents.

  A representative example of a practical organic radical is a nitroxide radical. The electronic structure of a nitroxide radical is represented by resonance between a structure in which an unpaired electron is on an oxygen atom and a structure on a nitrogen atom. Furthermore, since the nitroxide radical exhibits Lewis basicity due to the unshared electron pair on the oxygen atom, it has coordination ability with metal ions and proton acceptability of hydrogen bonds. In recent years, organic devices using nitroxide radicals have been actively reported, and various methods of using them as photoelectric conversion elements have been proposed.

  For example, Non-Patent Document 1, Patent Document 1 and Patent Document 2 describe 2,2,6,6-tetramethylpiperidine-N-oxyl (hereinafter also referred to as “TEMPO”) instead of a highly corrosive free iodine compound. .) Or a derivative thereof as a redox mediator is described. Patent Document 3 describes a light-absorbing material having a ligand with a radical site. Patent Document 4 and Patent Document 5 describe a photoelectric conversion element including an organic compound layer made of a radical compound between an electrode and a charge transport layer.

  By the way, in non-conjugated organic radical compounds represented by TEMPO, semi-occupied molecular orbitals (hereinafter also referred to as “SOMO”) are localized at the nitroxide site. Therefore, although it is excellent in the reversible stability of the oxidation-reduction reaction, it is not necessarily an optimal structure from the viewpoint of interaction with other substances, and further improvement is required as a material for the photoelectric conversion element. In particular, when used as a redox mediator of a dye-sensitized solar cell, there is a need for improvement in interaction with the complex dye.

  On the other hand, Non-Patent Document 2 describes 2,2-diphenyl-1,2-dihydroquinoline-1-oxyl (hereinafter also referred to as “DPQN”) and derivatives thereof, which are π-conjugated organic radical compounds. . However, according to the known literature, only the self-integration function by the π conjugate plane has been studied.

JP 2009-76369 A JP 2010-205704 A JP 2011-6665 A JP 2003-100360 A JP 2009-21212 A

Z. Zhang, P. Chen, T. N. Murakami, S. M. Zakeeruddin, M. Gratzel, Adv. Funct. Mater. 18, 341-346 (2008) N. Yoshioka et al., Chem. Phys. Lett. 402, 11-16 (2005)

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a photoelectric conversion element in which the corrosiveness of the electrolyte layer is low and excellent in photoelectric conversion efficiency, and a π-conjugated organic radical compound constituting the photoelectric conversion element. And

The present inventor believes that the π-conjugated organic radical compound exists as a SOMO delocalized in the π-conjugated plane, so that when used as a photoelectric conversion element from the viewpoint of interaction with other substances. I thought that there might be an advantage. As a result of intensive research to solve the above problems, it was found that a specific π-conjugated organic radical compound contributes to the improvement of photoelectric conversion efficiency as a material of a new photoelectric conversion element having low corrosive properties. The invention has been completed. That is, the present invention is as follows.
[1] A photoelectric conversion element including a semiconductor electrode containing a semiconductor layer and a dye, a counter electrode, and an electrolyte layer provided between the semiconductor electrode and the counter electrode. The said photoelectric conversion element containing the (pi) conjugated organic radical compound shown by Formula (1).

(In the formula (1), the substituents represented by X ¹ , X ² , X ³ , X ⁴ , and X ⁵ are each independently an electron-withdrawing group, hydrogen, an alkyl group having 1 to 6 carbon atoms, carbon It is either an alkoxy group having 1 to 6 carbon atoms or a fluorine-substituted alkoxy group having 1 to 6 carbon atoms.)
[2] In the general formula (1), at least one of the substituents represented by X ¹ , X ² , X ³ , X ⁴ , and X ⁵ is an electron-withdrawing group, and the remaining substituents are The photoelectric conversion element according to [1], wherein each is independently hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a fluorine-substituted alkoxy group having 1 to 6 carbon atoms.
[3] The electron-withdrawing group, _F, Cl, with _{NO 2, CN, C 6 F} 5, and _C n _{F 2n +} 1 (n is an integer from 1 to 6) were each independently selected from the group consisting of group The photoelectric conversion element according to [2].
[4] The photoelectric conversion element according to any one of [1] to [3], wherein the dye is a metal complex dye.
[5] A π-conjugated organic radical compound represented by the following general formula (1).

(In formula (1), at least one of the substituents represented by X ¹ , X ² , X ³ , X ⁴ , and X ⁵ is an electron-withdrawing group, and the remaining substituents are each independently It is any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a fluorine-substituted alkoxy group having 1 to 6 carbon atoms.)
[6] The group in which the electron withdrawing group is independently selected from the group consisting of F, Cl, NO ₂ , CN, C ₆ F ₅ , and C _n F _{2n + 1} (n is an integer of 1 to 6). The π-conjugated organic radical compound according to [5].

  ADVANTAGE OF THE INVENTION According to this invention, the corrosivity of an electrolyte layer is low, and the photoelectric conversion element which is excellent in photoelectric conversion efficiency, and the (pi) conjugated organic radical compound which comprises it can be provided.

The cross-sectional schematic diagram of an example of the photoelectric conversion element of this invention. The IV curve of the photoelectric conversion element of an Example. The IV curve of the photoelectric conversion element of an Example. The IV curve of the photoelectric conversion element of a reference example. The IV curve of the photoelectric conversion element of a comparative example. The IV curve of the photoelectric conversion element of an Example. The IV curve of the photoelectric conversion element of an Example. The IV curve of the photoelectric conversion element of an Example. The IV curve of the photoelectric conversion element of an Example.

Hereinafter, embodiments of the present invention (hereinafter also referred to as “present embodiments”) will be described in detail.
(Photoelectric conversion element)
The photoelectric conversion element is an element that converts light energy into electric energy, and is defined as a term that includes a dye-sensitized solar cell.

  The photoelectric conversion element of this embodiment includes a semiconductor electrode containing a semiconductor layer and a dye, a counter electrode, and an electrolyte layer provided between the semiconductor electrode and the counter electrode. A π-conjugated organic radical compound represented by the following general formula (1) is included.

(In the formula (1), the substituents represented by X ¹ , X ² , X ³ , X ⁴ , and X ⁵ are each independently an electron-withdrawing group, hydrogen, an alkyl group having 1 to 6 carbon atoms, carbon It is either an alkoxy group having 1 to 6 carbon atoms or a fluorine-substituted alkoxy group having 1 to 6 carbon atoms.)
Here, in the π-conjugated organic radical compound represented by the general formula (1), at least one of substituents represented by X ¹ , X ² , X ³ , X ⁴ , and X ⁵ is electron withdrawing. And the remaining substituents are each independently hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a fluorine-substituted alkoxy group having 1 to 6 carbon atoms Is preferred. Further, the electron-withdrawing group, are _{F, Cl, NO 2, CN} , C 6 F 5, and _C n _{F 2n +} 1 (n is an integer from 1 to 6) were each independently selected from the group consisting of group Compounds are more preferred.
(Π-conjugated organic radical compound)
In the π-conjugated organic radical compound represented by the general formula (1), the NO site is protected by the shielding effect of the diphenyl skeleton, so that chemical stability is maintained even at room temperature. In addition, since the nitrogen atom of the nitroxide radical is on the six-membered ring structure of the π conjugate plane, the π conjugate plane does not open even in the redox state, and the long-term stability is excellent.

X ¹ , X ² , X ³ , X ⁴ , and X ⁵ introduced as substituents have two roles.

The first role is to control the spread of unpaired electron density into the π conjugate plane. Since the π-conjugated organic radical compound originally has SOMO extended to the π-conjugated plane, it is advantageous for interaction with other substances when used as a photoelectric conversion element compared to a non-conjugated organic radical compound. It is believed that there is. Therefore, by introducing an electron-withdrawing group as a substituent into X ¹ , X ² , X ³ , X ⁴ , or X ⁵ , the unpaired electron density in the π-conjugated plane can be increased, thereby interacting with other substances. This is preferable because of the effect of further increasing The introduction position of the electron withdrawing group is more preferably the position of X ¹ , X ² or X ³ , and the position of X ² is particularly preferable. Further, the electron-withdrawing group, are _{F, Cl, NO 2, CN} , C 6 F 5, and _C n _{F 2n +} 1 (n is an integer from 1 to 6) were each independently selected from the group consisting of group It is more preferable.

The second role is to control solubility in the solvent. When a substituent is introduced, the molecular volume is increased, which has the effect of reducing the self-assembly function of the π conjugate plane. In other words, physicochemical properties such as crystallinity and solubility can be controlled. In the case of the second role, the effect is not limited to the electron-withdrawing group, but the introduction position is preferably the position of X ⁴ or X ^{5 that} has little influence on the first role.
(Method for producing π-conjugated organic radical compound)
The π-conjugated organic radical compound in this embodiment can be produced by any one of the following two reaction routes. In the reaction formula, X ¹ , X ² , X ³ , X ⁴ , and X ⁵ are as described above.
[Reaction route 1]

[Reaction route 2]

First, the manufacturing method of the reaction route 1 shown by the said General formula (2) is demonstrated.

  In the reaction of (i), an ice-cooled chloroform solution of m-chloroperbenzoic acid is added dropwise to the same ice-cooled chloroform solution of the quinoline derivative (2A), and then the m-chloroperbenzoic acid is hydrolyzed with an aqueous alkaline solution. Decompose. Although there is no restriction | limiting in particular as aqueous alkali solution, It is preferable that it is sodium hydroxide aqueous solution. Chloroform phase is recovered through water washing with liquid separation, dried by adding a dehydrating agent. Although there is no restriction | limiting in particular as a dehydrating agent, It is preferable that it is anhydrous sodium sulfate or anhydrous magnesium sulfate. After removing the solvent, the resulting crude product is purified by silica gel column chromatography to obtain compound (2B). Although there is no restriction | limiting in particular as a developing solvent of a silica gel column chromatography, For example, the developing solvent etc. which were ethyl acetate: n-hexane = 1: 1 (volume ratio) are mentioned.

In the reaction (ii), the compound (2B) is dissolved in dehydrated tetrahydrofuran and replaced with an inert gas. Although there is no restriction | limiting in particular as an inert gas, It is preferable that it is argon or nitrogen. A tetrahydrofuran solution containing 4-substituted phenylmagnesium bromide having substituent X ⁴ is added dropwise thereto and stirred. In addition, although there is no restriction | limiting in particular about reaction temperature, it is preferable that it is 0-60 degreeC, it is more preferable that it is 5-50 degreeC, and it is further more preferable that it is 10-40 degreeC. In this reaction, the reaction rate decreases at low temperature, and dehydration reaction occurs simultaneously at high temperature, resulting in a 2-phenylquinoline derivative from which oxygen is removed. Therefore, the reaction yield is increased by keeping the reaction temperature within the above range. Can do. After the reaction, it is neutralized with a neutralizing agent. Although there is no restriction | limiting in particular as a neutralizing agent, It is preferable that it is saturated ammonium chloride aqueous solution. Chloroform phase is recovered through water washing with liquid separation, dried by adding a dehydrating agent. Although there is no restriction | limiting in particular as a dehydrating agent, It is preferable that it is anhydrous sodium sulfate or anhydrous magnesium sulfate. After removing the solvent, it is dissolved in toluene and refluxed at the boiling point, and the crude product obtained after removing the toluene is purified by silica gel column chromatography to obtain compound (2C). Although there is no restriction | limiting in particular as a developing solvent of a silica gel column chromatography, For example, the developing solvent etc. which were ethyl acetate: n-hexane = 1: 1 (volume ratio) are mentioned.

In the reaction (iii), the compound (2C) is dissolved in dehydrated tetrahydrofuran and substituted with an inert gas. Although there is no restriction | limiting in particular as an inert gas, It is preferable that it is argon or nitrogen. This stirring was added dropwise a tetrahydrofuran solution containing 4-substituted phenyl magnesium bromide with a substituent X ⁵ at room temperature. In addition, although there is no restriction | limiting in particular about reaction temperature, it is preferable that it is 0-60 degreeC, it is more preferable that it is 5-50 degreeC, and it is further more preferable that it is 10-40 degreeC. In this reaction, the reaction rate decreases at low temperature, and dehydration reaction occurs simultaneously at high temperature, resulting in a 2-phenylquinoline derivative from which oxygen is removed. Therefore, the reaction yield is increased by keeping the reaction temperature within the above range. Can do. After the reaction, it is neutralized with a neutralizing agent. Although there is no restriction | limiting in particular as a neutralizing agent, It is preferable that it is saturated ammonium chloride aqueous solution. In this state, it is estimated that the N-OH body (2D) is formed, but characterization is difficult due to instability. Therefore, it is preferable to carry out the reaction (iv) following the reaction (iii).

  In the reaction (iv), the compound (2D) synthesized in (iii) is dissolved in chloroform and allowed to stand in the dark to be oxidized in air. The π-conjugated organic radical compound (2E) can be obtained by purifying the obtained crude product by silica gel column chromatography. Although there is no restriction | limiting in particular as a developing solvent of silica gel column chromatography, For example, chloroform etc. are mentioned.

  Next, the manufacturing method of the reaction route 2 shown by the said General formula (3) is demonstrated.

In the reaction (v), ethanol is added to the aniline derivative (3A) having the substituents X ¹ and X ² and dissolved by heating. A benzaldehyde derivative having a substituent X ⁴ is added thereto and refluxed at the boiling point. The precipitated crude crystals are separated by filtration and purified by washing with n-hexane to obtain compound (3B).

  In the reaction (vi), benzene is added to the compound (3B) and dissolved. Add distilled alkyl vinyl ether and boron trifluoride diethyl ether complex and stir with heating. Although there is no restriction | limiting in particular as alkyl vinyl ether, It is preferable that it is ethyl vinyl ether. Although there is no restriction | limiting in particular about reaction temperature, It is preferable that it is 25-60 degreeC, It is more preferable that it is 30-50 degreeC, It is further more preferable that it is 35-45 degreeC. The stirring time is preferably 1 to 72 hours, more preferably 5 to 48 hours, and further preferably 10 to 24 hours. The reaction (vi) proceeds even when acetonitrile is used as a solvent and diammonium cerium nitrate is added and stirred. The temperature is returned to room temperature, neutralized with an aqueous alkali solution, a chloroform solution is added, and after separation, the organic phase is recovered. Although there is no restriction | limiting in particular as aqueous alkali solution, It is preferable that it is sodium hydroxide aqueous solution. Then, the obtained crude product is purified by silica gel column chromatography to obtain compound (3C). Although there is no restriction | limiting in particular as a developing solvent of silica gel column chromatography, For example, chloroform etc. are mentioned.

In the reaction (vii), toluene is added to the compound (3C) and dissolved. Add diethyl azodicarboxylate and reflux at boiling point. Neutralize with an aqueous alkali solution, and after separation, the organic phase is recovered. Although there is no restriction | limiting in particular as aqueous alkali solution, It is preferable that it is sodium hydroxide aqueous solution. The resulting crude product is purified by silica gel column chromatography to obtain compound (3D). Although there is no restriction | limiting in particular as a developing solvent of silica gel column chromatography, For example, the developing solvent etc. which were chloroform: n-hexane = 1: 1 (volume ratio) are mentioned. When X ² is a halogen such as I, substitution with a C 1-6 alkoxy group or a C 1-6 fluorine-substituted alkoxy group is possible. Specifically, for example, a compound (3D) in which X ² is a halogen such as I is added to an alcohol having 1 to 6 carbon atoms or a fluorine-substituted alcohol having 1 to 6 carbon atoms, copper iodide, cesium carbonate, and 2- Add ethyl oxocyclohexacarboxylate and reflux at boiling point. The reaction time is preferably 1 to 72 hours, more preferably 5 to 48 hours, and even more preferably 10 to 24 hours. Thereafter, the organic phase is recovered by washing with water by liquid separation, and dried by adding a dehydrating agent. Although there is no restriction | limiting in particular as a dehydrating agent, It is preferable that it is anhydrous sodium sulfate or anhydrous magnesium sulfate. The crude product obtained the solvent after removal is purified by silica gel column chromatography substituents of X ₂ are obtained. Although there is no restriction | limiting in particular as a developing solvent of silica gel column chromatography, For example, the developing solvent etc. which were chloroform: n-hexane = 5: 1 (volume ratio) are mentioned.

  In the reaction (viii), the ice-cooled chloroform solution of m-chloroperbenzoic acid is added to the same ice-cooled chloroform solution of the compound (3D), and then m-chloroperbenzoic acid is hydrolyzed with an aqueous alkaline solution. . Although there is no restriction | limiting in particular as aqueous alkali solution, It is preferable that it is sodium hydroxide aqueous solution. Chloroform phase is recovered through water washing with liquid separation, dried by adding a dehydrating agent. Although there is no restriction | limiting in particular as a dehydrating agent, It is preferable that it is anhydrous sodium sulfate or anhydrous magnesium sulfate. After removing the solvent, the resulting crude product is purified by silica gel column chromatography to obtain compound (3E). Although there is no restriction | limiting in particular as a developing solvent of a silica gel column chromatography, For example, the developing solvent etc. which were ethyl acetate: n-hexane = 1: 1 (volume ratio) are mentioned.

In the reaction (ix), the compound (3E) is dissolved in dehydrated tetrahydrofuran and replaced with an inert gas. Although there is no restriction | limiting in particular as an inert gas, It is preferable that it is argon or nitrogen. This stirring was added dropwise a tetrahydrofuran solution containing 4-substituted phenyl magnesium bromide with a substituent X ⁵ at room temperature. In addition, although there is no restriction | limiting in particular about reaction temperature, it is preferable that it is 0-60 degreeC, it is more preferable that it is 5-50 degreeC, and it is further more preferable that it is 10-40 degreeC. In this reaction, the reaction rate decreases at low temperature, and dehydration reaction occurs simultaneously at high temperature, resulting in a 2-phenylquinoline derivative from which oxygen is removed. Therefore, the reaction yield is increased by keeping the reaction temperature within the above range. Can do. After the reaction, it is neutralized with a neutralizing agent. Although there is no restriction | limiting in particular as a neutralizing agent, It is preferable that it is saturated ammonium chloride aqueous solution. In this state, it is presumed to be an N—OH body (3F), but characterization is difficult due to instability. It is preferable to proceed to the reaction (x) following the reaction (ix).

  In the reaction (x), the compound (3F) is dissolved in chloroform and allowed to stand in the dark to be oxidized by air. A π-conjugated organic radical compound (3G) can be obtained by purifying the obtained crude product by silica gel column chromatography. Although there is no restriction | limiting in particular as a developing solvent of silica gel column chromatography, For example, chloroform etc. are mentioned.

  Specific examples of the π-conjugated organic radical compound in the present invention are illustrated below.

(Electrolyte layer)
The electrolyte layer 130 in this embodiment (FIG. 1) includes the π-conjugated organic radical compound and a liquid or solid electrolyte. The amount of the π-conjugated organic radical compound is preferably 1 to 50 parts by weight, more preferably 1.5 to 40 parts by weight, and more preferably 2 to 30 parts by weight with respect to 100 parts by weight of the electrolyte layer. Is particularly preferred. By being in this range, a charge transport function necessary for the electrolyte layer of the photoelectric conversion element is ensured, and an improvement in photoelectric conversion efficiency can be achieved without being affected by precipitation or concentration unevenness.

  Although there is no restriction | limiting in particular as a liquid electrolyte in this embodiment, It is preferable to comprise from a solvent and an additive.

  Examples of the solvent include nitrile solvents such as acetonitrile, methoxyacetonitrile, 3-methoxypropionitrile, and benzonitrile; nitrogen-containing compounds such as N-methylpyrrolidone, N, N-dimethylformamide, and 3-methyl-2-oxazolidinone. Solvent; Lactone solvents such as γ-butyrolactone and valerolactone; Carbonate solvents such as ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, propylene carbonate; Ether systems such as tetrahydrofuran, dioxane, diethyl ether, ethylene glycol dialkyl ether Solvent: Alcohol solvents such as methanol, ethanol, isopropyl alcohol, polypropylene glycol monoalkyl ether, dimethyl sulfoxide, Aprotic polar solvents Horan like; include such solvents, they are singly or may be mixed and used 2 or more kinds.

  As the solvent, an ionic liquid, that is, a molten salt can also be used. Further, the liquid electrolyte may contain a room temperature molten salt. Examples of the ionic liquid are disclosed in “Inorg. Chem.” 1996, 35, p1168-1178, “Electrochemistry” 2002.2, p130-136, JP-T 9-507334, JP-A-8-259543, and the like. It will not specifically limit if it can generally be used in a well-known battery, a solar cell, etc. Among them, a salt having a melting point lower than room temperature (25 ° C.), or a salt that liquefies at room temperature by dissolving other molten salts or additives other than the molten salt even if it has a melting point higher than room temperature Is preferably used.

  Specifically, as the cation of the molten salt, ammonium, imidazolium, oxazolium, thiazolium, piperidinium, pyrazolium, isoxazolium, thiadiazolium, oxadiazolium, triazolium, pyrrolidinium, pyridinium, pyrimidinium, pyridazinium, pyrazinium, Triazinium, phosphonium, sulfonium, carbazolium, indolium, and derivatives thereof are preferable, and ammonium, imidazolium, pyridinium, piperidinium, pyrazolium, and sulfonium are particularly preferable.

The anion of the molten salt includes metal chlorides such as AlCl ₄ ⁻ and Al ₂ Cl ₇ ⁻ , PF ₆ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , N (CF ₃ SO ₂ ) ₂ ⁻ and CF _3. Fluorine-containing materials such as COO ⁻ , NO ₃ ⁻ , CH ₃ COO ⁻ , C ₆ H ₁₁ COO ⁻ , CH ₃ OSO ₃ ⁻ , CH ₃ OSO ₂ ⁻ , CH ₃ SO ₃ ⁻ , CH ₃ SO ₂ ⁻ , (CH Non-fluorine compounds such as ₃ O) ₂ PO ₂ ^— , halides such as chlorine, bromine, iodine and the like.

  The molten salt can be synthesized by methods known in various literatures and publications. Taking a quaternary ammonium salt as an example, a quaternization of an amine is performed using a tertiary amine as an alkylating agent as an alkylating agent as a first step, and an ion exchange from a halide anion to a target anion is performed as a second step. Can be used. Alternatively, there is a method of obtaining a target compound in one step by reacting a tertiary amine with an acid having a target anion.

  As the solvent, it is more preferable to use a nitrile compound having a high ion conductivity or a room temperature molten salt.

  The π-conjugated organic radical compound in the present invention becomes a cation state by an oxidation reaction in a photoelectric conversion process. In order to stabilize this cationic state, it is also possible to add a salt as an additive.

  Examples of the salt used as the additive include, as cations, lithium, sodium, potassium, cesium, calcium, nitrosonium, ammonium, tetraalkylammonium, imidazolium, oxazolium, thiazolium, piperidinium, pyrazolium, isoxazolium, thiadiazo Examples include lithium, oxadiazolium, triazolium, pyrrolidinium, pyridinium, pyrimidinium, pyridazinium, pyrazinium, triazinium, phosphonium, sulfonium, carbazolium, indolium, and their derivatives, lithium, nitrosonium, ammonium, imidazolium, pyridinium, piperidinium , Pyrazolium and sulfonium are preferred.

In addition, the anion includes fluorine such as PF ₆ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , N (CF ₃ SO ₂ ) ₂ ⁻ , F (HF) _j ⁻ (j is an integer), CF ₃ COO ^{− and the} like. NO ₃ ⁻ , CH ₃ COO ⁻ , C ₆ H ₁₁ COO ⁻ , CH ₃ OSO ₃ ⁻ , CH ₃ OSO ₂ ⁻ , CH ₃ SO ₃ ⁻ , CH ₃ SO ₂ ⁻ , (CH ₃ O) ₂ PO ₂ ^-, SbCl ₆ ^- non-fluorinated compounds such as iodine, and halides such as bromine and the like. Other specific combinations include metal complexes such as ferrocyanate-ferricyanate, ferrocene-ferricinium ion, sulfur compounds such as sodium polysulfide, alkylthiol-alkyldisulfide, viologen dyes, hydroquinone-quinone, etc. Can be mentioned. These salts may be a single combination or a mixture. The salt concentration in the electrolyte layer is preferably 0.05 to 20 mol / l, and more preferably 0.1 to 15 mol / l. By being in this range, a charge transport function necessary for the electrolyte layer of the photoelectric conversion element is ensured, and an improvement in photoelectric conversion efficiency can be achieved without being affected by precipitation or concentration unevenness.

  The solid electrolyte in the present invention is not particularly limited. For example, the liquid electrolyte is gelled or solidified by techniques such as addition of a polymer, addition of an oil gelling agent, addition of fine particles, polymerization including polyfunctional monomers, and a polymer crosslinking reaction. Electrolytes. Examples of the polymer addition include addition of polyacrylonitrile, polyvinylidene fluoride, and the like. Examples of the oil gelling agent addition include dibenzylden-D-sorbitol, cholesterol derivatives, amino acid derivatives, trans- (1R, 2R) -1,2-cyclohexanediamine alkylamide derivatives, alkylurea derivatives, N-octyl-D- Addition of gluconamide benzoate, double-headed amino acid derivative, quaternary ammonium derivative and the like can be mentioned.

  There is no restriction | limiting in particular as the formation method of the electrolyte layer in this invention, For example, microgravure coating, dip coating, screen coating, spin coating etc. can be used. In the case of a solid electrolyte, for example, after making a solution with an arbitrary solvent, the solution may be applied to the electrode using the above method and heated to an arbitrary temperature to evaporate the solvent.

(Semiconductor electrode)
The semiconductor electrode 120 in this embodiment (FIG. 1) includes a conductive substrate and a semiconductor layer 121 formed thereon, and the conductive substrate and the semiconductor layer are stacked in this order from the outside to the inside of the photoelectric conversion element 110. doing. In addition, the semiconductor layer 121 contains a dye that functions as a photosensitizer.

  The conductive substrate includes an electrode substrate 123 and a transparent conductive layer 122, and the surface of the transparent conductive layer is in contact with the semiconductor layer. The material used for the electrode substrate is not particularly limited as long as it is transparent. Specifically, glass such as glass and tempered glass, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene sulfide, polystyrene, polymethyl methacrylate, polymethacrylate, acrylic resin, polyvinyl chloride, triacetyl cellulose Polyolefin-based plastic films such as polyimide, cyclic polyolefin, polyethylene, and polypropylene can be used.

  When the material is a plastic film, the thickness of the electrode substrate is preferably 10 to 500 μm, more preferably 50 to 200 μm, and particularly preferably 100 to 200 μm. In the case of glass, 0.1 to 5 mm is preferable, 0.5 to 4 mm is more preferable, and 0.5 to 2.5 mm is particularly preferable. Further, when the electrode base material is used as a light incident surface, it is preferable that the transmittance in the visible light region is 85% or more, has excellent weather resistance, and has a strength that can withstand as an indicator. Such an electrode base material may have a surface modified by corona treatment, plasma treatment, chemical treatment, or the like, if necessary.

As the transparent conductive layer, a known transparent conductive material having little absorption in the visible light region and having conductivity can be used. As the transparent conductive material, indium oxide doped with tin (ITO), indium oxide doped with zinc (IZO), tin oxide doped with fluorine, indium, antimony or the like, zinc oxide doped with aluminum, gallium, or the like is preferable. . In addition, a three-layer transparent conductive material in which silver or a silver alloy (AgAuCu or the like) is sandwiched between ITO, TiO ₂ , ZnO, or the like is also included. Among these, it is particularly preferable to use tin oxide doped with ITO or fluorine.

  The transparent conductive layer can be formed by a vacuum film forming process such as a vacuum deposition method, a reactive deposition method, an ion beam assisted deposition method, a sputtering method, an ion plating method, or a plasma CVD method. However, it is not limited to these examples, and any film forming method may be used. The thickness of the transparent conductive layer is preferably 50 nm to 1 μm. Although depending on conditions, in the case of ITO, a film thickness of 100 to 400 nm is preferable, and in the case of fluorine-doped tin oxide, 300 to 900 nm is preferable. The transparent conductive layer preferably has a visible light transmittance of 65% or more.

Examples of the material constituting the semiconductor layer in this embodiment include metal oxides exhibiting n-type or p-type semiconductor properties, such as zinc, niobium, tin, titanium, vanadium, indium, tungsten, tantalum, and zirconium. , Molybdenum, manganese, iron, copper, nickel, iridium, rhodium, chromium, and ruthenium oxides. Further, perovskites such as SrTiO ₃ , CaTiO ₃ , BaTiO ₃ , MgTiO ₃ , SrNb ₂ O ₆ , cadmium sulfide, etc., or complex oxides or oxide mixtures thereof can also be used. These semiconductor materials can be used alone or in combination of two or more.

  Among these, from the viewpoint of conversion efficiency, stability, and safety, the semiconductor layer is preferably made of a semiconductor material containing titanium oxide. More specifically, examples of titanium oxide include anatase-type titanium oxide, rutile-type titanium oxide, amorphous titanium oxide, various titanium oxides such as metatitanic acid and orthotitanic acid, and titanium oxide-containing composites. Among these, anatase type titanium oxide is preferable from the viewpoint of further improving the stability of photoelectric conversion. The semiconductor layer may be porous titania.

  Examples of the shape of the semiconductor layer include a porous semiconductor layer obtained by sintering semiconductor fine particles and the like, and a thin film semiconductor layer obtained by a sol-gel method, a sputtering method, a spray pyrolysis method, and the like. Moreover, it is good also as a semiconductor layer which consists of a fibrous semiconductor layer and an acicular crystal | crystallization. The shape of the semiconductor layer can be appropriately selected according to the purpose of use of the photoelectric conversion element.

  Among these, a semiconductor layer having a large specific surface area such as a porous semiconductor layer or a needle-like crystal is preferable from the viewpoint of the amount of dye adsorbed. Furthermore, from the viewpoint that the utilization factor of incident light and the like can be adjusted by the particle size of the semiconductor fine particles, it is preferable to use a porous semiconductor layer formed of semiconductor fine particles as the semiconductor layer.

  Further, the semiconductor layer may be a single layer or a multilayer. By forming a multilayer, a sufficiently thick semiconductor layer can be more easily formed.

  The porous multilayer semiconductor layer formed from semiconductor fine particles may be composed of a plurality of semiconductor layers having different average particle diameters of the semiconductor fine particles. For example, by reducing the average particle size of the semiconductor fine particles of the semiconductor layer closer to the light incident side (first semiconductor layer) than that of the semiconductor layer farther from the light incident side (second semiconductor layer), the first semiconductor The layer absorbs a large amount of light, and the light that has passed through the first semiconductor layer is efficiently scattered by the second semiconductor layer, returned to the first semiconductor layer, and absorbed by the first semiconductor layer. The rate can be further improved.

Although the film thickness of a semiconductor layer is not specifically limited, 0.5-45 micrometers is preferable from viewpoints, such as permeability | transmittance and conversion efficiency. The specific surface area of the semiconductor layer is preferably 10 to 200 m ² / g from the viewpoint of including a large amount of dye by adsorption.

  In addition, as a configuration in which a dye is adsorbed on a porous semiconductor layer, the porosity of the porous semiconductor layer is set to 40 to 80% in order for ions in the electrolyte to be more sufficiently diffused to perform charge transport. It is preferable. The porosity is the percentage of the volume of the semiconductor layer occupied by the voids in the semiconductor layer in%.

  Next, a method for forming the semiconductor layer will be described taking a porous semiconductor layer as an example. The porous semiconductor layer is prepared, for example, by adding a semiconductor fine particle together with an organic compound such as a polymer and a dispersing agent to a dispersion medium such as an organic solvent or water, and preparing the suspension on the transparent conductive layer. It is formed by applying, drying and baking.

  When an organic compound is added to the dispersion medium together with the semiconductor fine particles, the organic compound is combusted at the time of firing, and a sufficient gap can be secured in the porous semiconductor layer. Moreover, the porosity can be changed by controlling the molecular weight and the addition amount of the organic compound combusted during firing. The type and amount of the organic compound can be appropriately selected and adjusted depending on the state of the fine particles used, the total weight of the entire suspension, and the like. However, when the ratio of the semiconductor fine particles is 10 wt% or more with respect to the total weight of the entire suspension, the strength of the produced film can be further sufficiently increased, and the ratio of the semiconductor fine particles is If it is 40 wt% or less with respect to the total weight, a porous semiconductor layer having a large porosity can be obtained more stably. Therefore, the ratio of the semiconductor fine particles is 10 to 40 wt with respect to the total weight of the entire suspension. % Is preferred.

  As the semiconductor fine particles, single semiconductor particles or compound semiconductor particles having an appropriate average particle diameter, for example, an average particle diameter of about 1 to 500 nm are used. Among them, an average particle diameter of about 1 to 50 nm is desirable from the viewpoint of increasing the specific surface area. In order to increase the utilization rate of incident light, semiconductor particles having a relatively large average particle diameter of about 200 to 400 nm may be added.

  Examples of the method for producing semiconductor fine particles include sol-gel methods such as hydrothermal synthesis, sulfuric acid method, chlorine method and the like, and any method can be used as long as it can produce the desired fine particles. From the viewpoint of crystallinity, it is preferable to synthesize by a hydrothermal synthesis method.

  Any organic compound can be used as long as it dissolves in the suspension and can be removed by burning when baked. Examples thereof include polymers such as polyethylene glycol and ethyl cellulose. Examples of the dispersion medium for the suspension include glyme solvents such as ethylene glycol monomethyl ether; alcohols such as isopropyl alcohol; and mixed solvents such as isopropyl alcohol / toluene; and water.

  Examples of the method for applying the suspension include known methods such as a doctor blade method, a squeegee method, a spin coating method, and a screen printing method. Thereafter, the coating film is dried and fired. The drying and firing conditions are, for example, about 10 seconds to 12 hours in the range of about 50 to 800 ° C. in the air or in an inert gas atmosphere. This drying and baking can be performed once at a single temperature or twice or more by changing the temperature.

Although the method for forming the porous semiconductor layer has been described in detail here, other types of semiconductor layers can also be formed using various known methods. For example, for forming a metal oxide film, a metal, metal oxide, metal suboxide, or the like corresponding to the metal oxide to be formed is used as an evaporation source, an evaporation method using heating with an electron beam or a plasma gun, or oxygen gas. A reactive vapor deposition method in which vapor deposition is performed while introducing can be used. The film forming pressure varies depending on the type of vapor deposition source used, but it is preferably performed in the range of 1 × 10 ^{−2 to} 1 Pa. During film formation, assist may be performed by plasma using any gas, an ion gun, a radical gun, or the like. The substrate temperature can be arbitrarily selected between −50 ° C. and 600 ° C., but is preferably 300 ° C. or lower in order to keep the porosity high. Depending on the target metal oxide, a vacuum film forming method such as sputtering, ion plating, or CVD may be used. Further, when a plastic film is used as the base material, higher productivity can be obtained if the film is formed by a roll-to-roll method.

  The metal oxide film obtained as described above can be surface-treated by any method such as plasma treatment, corona treatment, UV treatment, and chemical treatment. Further, post-treatment can be performed using any means such as baking by heat, pressurizing treatment using a compressor, laser annealing, or the like.

(Dye)
In this embodiment, the dye contained in the semiconductor layer functions as a photosensitizer. Specifically, it is preferable that the dye has absorption in various visible light regions and infrared light regions, has a large absorption coefficient, and is stable against repeated redox. Also, in order to adsorb firmly to the semiconductor layer, carboxyl (COOH) group, alkoxy group, hydroxyl group, hydroxyalkyl group, sulfonic acid group, ester group, mercapto group, phosphonyl group, amide group, amino group in the dye molecule And those having an interlock group such as a carbonyl group and a phosphate group. Among these, those having a carboxyl group are particularly preferable from the viewpoint of more stably adsorbing the dye to the surface of the porous semiconductor.

  The interlock group provides an electrical bond that facilitates electron transfer between the excited state energy band of the dye and the conduction band of the semiconductor. Examples of these dyes containing an interlock group include Ru metal complex dyes (ruthenium bipyridine metal complex dyes, ruthenium terpyridine metal complex dyes, ruthenium quarter pyridine metal complex dyes, etc.), Os metal complex dyes, and Fe metals. Complex dyes, Cu metal complex dyes, Pt metal complex dyes, Re metal complex dyes and other metal complex dyes, cyanine dyes, merocyanine dyes, azo dyes, quinone dyes, quinone imine dyes, quinacridone dyes, squarylium dyes , Triphenylmethane dyes, xanthene dyes, porphyrin dyes, phthalocyanine dyes, perylene dyes, indigo dyes, naphthalocyanine dyes, coumarin dyes, mercurochrome dyes, cyanidin dyes, rhodamine dyes, etc. It is done. Among these, from the viewpoint of the stability of the photoelectric conversion reaction, a metal complex dye is preferable, and a Ru metal complex dye is more preferable.

  Examples of the method for adsorbing the dye on the semiconductor layer include a method in which a semiconductor layer formed on a conductive substrate is immersed in a solution in which the dye is dissolved. Solvents used for dissolving the dye include, for example, alcohols such as ethanol; ketones such as acetone; ethers such as diethyl ether and tetrahydrofuran; nitrogen compounds such as acetonitrile; halogenated aliphatic hydrocarbons such as chloroform; Aliphatic hydrocarbons such as benzene, aromatic hydrocarbons such as benzene, and esters such as ethyl acetate. These solvents may be used as a mixture of two or more.

The concentration of the dye in the solution and the kind of the dye and solvent to be used can be adjusted as appropriate. However, from the viewpoint of improving the adsorption function, a somewhat high concentration is preferable, for example, 5 × 10 ⁻⁵ mol / l. It is sufficient if the concentration is above.

  When the conductive substrate on which the semiconductor layer is formed is immersed in the solution in which the dye is dissolved, the temperature and pressure of the solution and the atmosphere are not particularly limited, and examples include about room temperature and atmospheric pressure, and the immersion time. Can be appropriately adjusted depending on the dye used, the type of solvent, the concentration of the solution, and the like. In order to effectively perform the immersion, the immersion may be performed under heating. Thereby, a pigment | dye can be made to adsorb | suck more efficiently to a semiconductor layer. Further, when adsorbing the dye, in order to control the adsorption state of the dye, deoxycholic acid, guanidine thiocyanate, tert-butylpyridine, N-methylbenzimidazole, N- (n-butyl) benzimidazole is added to the solution in which the dye is dissolved. Organic compounds such as ethanol may be added.

(Counter electrode)
The counter electrode 140 in this embodiment (FIG. 1) is not particularly limited as long as it has smoothness enough to form a conductive film and has a strength enough to sandwich a sealing material. Any material such as an inorganic material, an organic material, or a metal material can be used. Specific examples include noble metal materials such as platinum, gold, and silver, and conductive materials such as copper, aluminum, and carbon. In consideration of corrosion and long-term durability, noble metal materials such as platinum, gold, and silver and carbon are preferable, and it is also preferable from the viewpoint of economy to use a glass or plastic film on which these noble metals or carbon is deposited. Moreover, in order to obtain a photoelectric conversion element having visible light transparency, a transparent conductive film such as ITO, tin oxide, or fluorine-doped tin oxide can be used. The thickness of the counter electrode is preferably 10 to 3000 μm and more preferably 50 to 1000 μm in consideration of strength and light weight of the product, although it depends on the material.

  You may provide a conductive catalyst layer in the counter electrode in this invention as needed. As the conductive catalyst layer, any conductive material can be used, and examples thereof include metals such as platinum, gold, silver, and copper, or carbon. In addition, conductive materials such as polyaniline, polythiophene, PEDOT, and polypyrrole can be used. In forming these, a vacuum film forming method similar to that of the transparent conductive layer, or a method of wet coating a paste made of fine particles of these materials can be used.

  The conductive catalyst layer preferably has a thickness of 0.1 to 2000 nm, more preferably 1 to 500 nm, and still more preferably 5 to 200 nm. When a highly corrosive free iodine compound or the like is included, it is preferable to use a material that is resistant to corrosion, such as platinum and carbon, as the conductive catalyst.

(Encapsulant)
In the photoelectric conversion element of the present invention, a sealing material 150 (FIG. 1) for sealing the electrolyte layer may be provided between the semiconductor electrode and the counter electrode. The sealing material is required to have weather resistance, light resistance, high moisture resistance, heat resistance, and the like, and in order to prevent evaporation of the electrolytic solution, a substance insoluble in the electrolytic solution is preferable. Specific examples include resins such as polyethylene and ethylene vinyl acetate processed into a film. These sealing materials are bonded to the periphery of the electrode, fused by heating or heating while applying pressure, and the periphery thereof is bonded using an epoxy resin, silicon resin, etc. Can be more effectively prevented.

  The photoelectric conversion element in the present invention can be used not only as a dye-sensitized solar cell but also as an optical sensor.

  Usually, an organic compound having a radical is extremely unstable and easily breaks when physical energy such as heating is applied from the outside as in the vapor deposition technique. Therefore, it has been difficult to make a device using an organic radical compound. However, in the π-conjugated organic radical compound of the present invention, film formation methods such as a vacuum deposition method, an ionization deposition method, a sputtering method, and a plasma method have become possible due to its excellent stability. This makes it possible to develop completely new applications and is expected to be applied to industrial and consumer fields. For example, organic devices such as organic electroluminescence elements, organic solar cells, organic transistors, organic memories, and quantum computers.

  Although the present invention has been described above, the present invention is not limited to the above. The present invention can be variously modified without departing from the gist thereof.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

[Example 1]
(1) Derivation of 2-phenylquinoline to 2-phenylquinoline-1-oxide 1.2 g (4.5 mmol) of m-chloroperbenzoic acid (purity 65%, manufactured by Tokyo Chemical Industry Co., Ltd.) in 20 ml of chloroform The dissolved solution was ice-cooled, slowly added to 100 ml of chloroform containing 1.0 g (4.9 mmol) of 2-phenylquinoline (Aldrich), which was also ice-cooled, and stirred for 24 hours. Further, 20 ml of a chloroform solution in which 1.2 g (4.5 mmol) of m-chloroperbenzoic acid (manufactured by Tokyo Chemical Industry Co., Ltd., purity 65%) was dissolved was added and stirred for 24 hours. Thereafter, 100 ml of 1M NaOH aqueous solution was added for neutralization. After washing several times with water, the chloroform phase was recovered and dried over anhydrous sodium sulfate. After removing the solvent, the resulting crude product was purified by silica gel column chromatography (developing solvent: ethyl acetate: n-hexane = 1: 2) to obtain 0.78 g (yield 73%) of the desired product as a light yellow solid. It was. Formation of the target product was confirmed by mass spectrum and ¹ H-NMR.

(2) Induction from 2-phenylquinoline-1-oxide to 2,2-diphenyl-1,2-dihydroquinoline-1-oxyl 500 mg (2.3 mmol) of 2-phenylquinoline-1-oxide is added to a three-necked flask. The solution was dissolved in 40 ml of tetrahydrofuran (manufactured by Kanto Chemical Co., Inc., for organic synthesis) and purged with nitrogen. To this, 4.5 ml of phenylmagnesium bromide (manufactured by Kanto Chemical Co., Inc., 1.0 mol / l tetrahydrofuran solution) was added dropwise with a syringe, and after stirring for 2 hours, a saturated aqueous ammonium chloride solution was added for neutralization. This was dissolved in 100 ml of chloroform and allowed to stand in the dark for 12 hours. The obtained crude product was purified by silica gel column chromatography (developing solvent: chloroform: n-hexane = 1: 2) to obtain 350 mg of reddish brown liquid (yield 52%). Formation of the target product was confirmed by mass spectrum and ESR. The synthesis was repeated to secure an amount necessary for manufacturing the photoelectric conversion element.

(3) Production of photoelectric conversion element using organic dye 30 mg of hibiscus powder (wood of life) was dissolved in 20 ml of dehydrated ethanol (manufactured by Kanto Chemical Co., Inc., for organic synthesis) to prepare a saturated dye solution. . As a semiconductor electrode, an electrode base material, a transparent electrode layer, and a titanium dioxide baked electrode composed of a semiconductor layer (manufactured by Nishinoda Electric Co., Ltd., trade name: BY1) were prepared. The semiconductor layer of the semiconductor electrode was scraped off leaving a range of 1 cm × 1 cm at the center, and then immersed in the saturated dye solution and allowed to stand for 24 hours, thereby adsorbing the dye to the semiconductor layer. Then, it vacuum-dried at room temperature for 1 hour, and produced the semiconductor electrode.

  Next, 10 g of acetonitrile (manufactured by Kanto Chemical Co., Ltd., special grade), 0.46 g of 2,2-diphenyl-1,2-dihydroquinolin-1-oxyl, bis (trifluoromethanesulfonyl) imide lithium (Wako Pure Chemical Industries, Ltd.) 4.4 g, Nitrosyltetrafluoroborate (Aldrich) 18 mg, N- (n-butyl) benzimidazole (D. Kuang, C. Klein, S. Ito, J.-E. Moser, R) Humphry-Baker, N. Evans, F. Duriaux, C. Gratzel, SM Zakeeruddin, M. Gratzel, Adv. Mater. 19, 1133-1137 (2007)) did.

  A parafilm (registered trademark, manufactured by LMS Co., Ltd.) was wound around the semiconductor layer, and then 20 μl of the electrolyte (a) was dropped into the semiconductor layer and sufficiently immersed. Then, the film with a counter electrode catalyst (Peccell Technologies Co., Ltd. product, PECF-CAT) provided with a platinum catalyst layer was opposed as a counter electrode and fixed with a jig to produce a photoelectric conversion element.

This photoelectric conversion element was evaluated using a dye-sensitized solar cell evaluation system manufactured by Pexel Technologies. A semiconductor electrode and a counter electrode are connected to an IV characteristic measuring device PECK2400-N2, and light is irradiated from the semiconductor electrode side using a simple solar simulator PEC-L01, under the conditions of AM1.5 and 100 mW / cm ² irradiation Current (I) -voltage (V) measurement was performed. The obtained IV curve is shown in FIG. Table 1 shows the short-circuit current (I _SC ), open-circuit voltage (V _OC ), fill factor (FF), and photoelectric conversion efficiency (η) of the IV curve together with the results of the reference examples described later. The photoelectric conversion efficiency was calculated as follows.

η (unit:%) = P _out / P _in = 100 × FF × (I _SC × V _OC ) / (L × A)
Here, FF = (I _max × V _max ) / (I _SC × V _OC )
FF = fill factor I _SC (unit: mA) = short circuit current V _OC (unit: V) = open circuit voltage L (unit: mW / cm ² ) = irradiation intensity = 100 mW / cm ²
A (unit: cm ² ) = active region = 1 cm ²
I _max (unit: mA) = current at maximum power point V _max (unit: V) = voltage at maximum power point

[Example 2]
Preparation of photoelectric conversion element using metal complex dye Dye using cis-bis (isothiocyanato) bis (2,2′-bipyridyl-4,4′-dicarboxylato) ruthenium (II) (manufactured by Aldrich) as the dye A photoelectric conversion element was produced and evaluated in the same manner as in Example 1 (3) except that the concentration of the solution was 0.3 mmol / l. The obtained IV curve is shown in FIG. Table 2 shows the short-circuit current (I _SC ), open-circuit voltage (V _OC ), fill factor (FF), and photoelectric conversion efficiency (η) of the IV curve together with the results of Comparative Example 1 described later.

[Reference example]
Production of photoelectric conversion element using organic dye 10 g of acetonitrile (manufactured by Kanto Chemical Co., Ltd., special grade), 2 g of TEMPO (manufactured by Aldrich), bis (trifluoromethanesulfonyl) imide lithium (manufactured by Wako Pure Chemical Industries, Ltd.) 4.4 g, 150 mg of nitrosyltetrafluoroborate (Aldrich), N- (n-butyl) benzimidazole (D. Kuang, C. Klein, S. Ito, J.-E. Moser, R. Humphry-Baker, 1 g of N) Evans, F. Duriaux, C. Gratzel, SM Zakeeruddin, M. Gratzel, Adv. Mater. 19, 1133-1137 (2007) was added to prepare an electrolyte solution (b).
A photoelectric conversion element was produced and evaluated in the same manner as in Example 1 (3) except that the electrolytic solution (b) was used instead of the electrolytic solution (a). The obtained IV curve is shown in FIG. Table 1 shows the short-circuit current (I _SC ), open-circuit voltage (V _OC ), fill factor (FF), and photoelectric conversion efficiency (η) of the IV curve.

[Comparative Example 1]
Production of photoelectric conversion element using metal complex dye A photoelectric conversion element was produced and evaluated in the same manner as in Example 2 except that the electrolytic solution (b) was used instead of the electrolytic solution (a). The obtained IV curve is shown in FIG. Table 2 shows the short-circuit current (I _SC ), open-circuit voltage (V _OC ), fill factor (FF), and photoelectric conversion efficiency (η) of the IV curve. Unlike the organic dye, the metal complex dye hardly functioned as a photoelectric conversion element.

[Example 3]
(1) Derivation from 4-chloroaniline to benzylidene- (4-chloroaniline) 12.7 g (0.10 mol) of 4-chloroaniline (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to 60 ml of methanol (Pure Chemical Co., Ltd.) Manufactured, special grade). 10.9 g (0.103 mol) of distilled benzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) was added thereto, refluxed for 30 minutes, and then allowed to cool. The precipitated crude crystals were separated by filtration and washed with n-hexane. 20.6 g of the target product was obtained as a white solid (yield 96%). Formation of the target product was confirmed by mass spectrum and ¹ H-NMR.

(2) Derivation of benzylidene- (4-chloroaniline) to 2-phenyl-4-ethoxy-6-chloro-1,2,3,4-tetrahydroquinoline 2.15 g of benzylidene- (4-chloroaniline) (0 .01 mol) was dissolved in 100 ml of acetonitrile (manufactured by Kanto Chemical Co., Ltd., special grade). Distilled ethyl vinyl ether (Tokyo Chemical Industry Co., Ltd., grade 1, 2.16 g (0.03 mol) and diammonium cerium nitrate (Kanto Chemical Co., Ltd., special grade) 0.28 g (0.5 mmol) were added to room temperature. For 1 hour. Then, it extracted with dichloromethane. After removing the solvent, the residue was purified by silica gel column chromatography (developing solvent: chloroform: n-hexane = 1: 1) to obtain 1.0 g of a green liquid (yield 35%). Formation of the target product was confirmed by mass spectrum and ¹ H-NMR.

(3) Induction of 2-phenyl-4-ethoxy-6-chloro-1,2,3,4-tetrahydroquinoline to 2-phenyl-6-chloroquinoline Into a recovery flask, 2-phenyl-4-ethoxy-6- 2.07 g (0.01 mol) of chloro-1,2,3,4-tetrahydroquinoline and 60 ml of toluene (manufactured by Kanto Chemical Co., Ltd., special grade) were added and dissolved. At room temperature, 6 ml (23.2 mmol) of diethyl azodicarboxylate (manufactured by Tokyo Chemical Industry Co., Ltd., 40% toluene solution) was added and refluxed for 24 hours. The mixture was neutralized with sodium hydroxide solution, and after separation, the organic phase was recovered. The resulting crude product was purified by silica gel column chromatography (developing solvent: chloroform) to obtain 1.80 g (yield 75%) of a beige solid. Formation of the target product was confirmed by mass spectrum and ¹ H-NMR.

(4) Derivation from 2-phenyl-6-chloroquinoline to 2-phenyl-6-chloroquinoline-1-oxide m-chloroperbenzoic acid (manufactured by Tokyo Chemical Industry Co., Ltd., purity 65%) 1.12 g ( A solution of 4.2 mmol) dissolved in 20 ml of chloroform was ice-cooled, and the solution was added dropwise to 100 ml of chloroform containing 0.96 g (4.0 mmol) of 2-phenyl-6-chloroquinoline, which was also ice-cooled, and stirred for 24 hours. Further, 20 ml of a chloroform solution in which 1.12 g (4.2 mmol) of m-chloroperbenzoic acid was dissolved was added and stirred for 24 hours. Thereafter, 100 ml of a 1N aqueous sodium hydroxide solution was added for neutralization. After washing three times with water, the chloroform phase was recovered and dried over anhydrous sodium sulfate. After removing the solvent, the resulting crude product was purified by silica gel column chromatography (developing solvent: chloroform) to obtain 0.86 g (yield 79%) of the target product as a light yellow solid. Formation of the target product was confirmed by mass spectrum and ¹ H-NMR.

(5) Derivation from 2-phenyl-6-chloroquinoline-1-oxide to 2,2-diphenyl-6-chloro-1,2-dihydroquinoline-1-oxyl 2-phenyl-6-chloroquinoline-1- 77 mg (0.3 mmol) of oxide was placed in a three-necked flask, dissolved in 5 ml of tetrahydrofuran (manufactured by Kanto Chemical Co., Inc., for organic synthesis), and purged with nitrogen. To this, 1.0 ml of phenylmagnesium bromide (manufactured by Kanto Chemical Co., Inc., 1 mol / l tetrahydrofuran solution) was added dropwise with a syringe and stirred for 2 hours. After the reaction, a saturated aqueous ammonium chloride solution was added for neutralization. This was dissolved in 100 ml of chloroform and allowed to stand in the dark for 12 hours. The resulting crude product was purified by silica gel column chromatography (developing solvent: chloroform: n-hexane = 2: 1) to obtain 40 mg of reddish brown liquid (yield 40%). Formation of the target product was confirmed by mass spectrum, elemental analysis, and ESR. The synthesis was repeated to secure an amount necessary for manufacturing the photoelectric conversion element.

(6) Production of photoelectric conversion element using metal complex dye 2,2-diphenyl-6-chloro-1,2-dihydroquinoline-1-oxyl was added to 10 g of acetonitrile (manufactured by Kanto Chemical Co., Ltd., special grade). 4 g, 4.4 g of bis (trifluoromethanesulfonyl) imide lithium (manufactured by Wako Pure Chemical Industries, Ltd.), 225 mg of nitrosyltetrafluoroborate (manufactured by Aldrich), N- (n-butyl) benzimidazole (D. Kuang, C Klein, S. Ito, J.-E. Moser, R. Humphry-Baker, N. Evans, F. Duriaux, C. Gratzel, SM Zakeeruddin, M. Gratzel, Adv. Mater. 19, 1133-1137 (2007 ) 1 g) was added to prepare an electrolytic solution (c).

A photoelectric conversion element was produced and evaluated in the same manner as in Example 2 except that the electrolytic solution (c) was used instead of the electrolytic solution (a). The obtained IV curve is shown in FIG. Table 3 shows the short-circuit current (I _SC ), open-circuit voltage (V _OC ), fill factor (FF), and photoelectric conversion efficiency (η) of the IV curve.

[Example 4]
(1) Derivation from 2-phenylquinoline-1-oxide to 2-phenyl-2- (4-chlorophenyl) -1,2-dihydroquinoline-1-oxyl Obtained in the same manner as in Example 1 (1). 500 mg (2.3 mmol) of 2-phenylquinoline-1-oxide was placed in a three-necked flask and dissolved in 40 ml of tetrahydrofuran (manufactured by Kanto Chemical Co., Inc., for organic synthesis), and the atmosphere was replaced with nitrogen. To this, 4.5 ml of 4-chlorophenylmagnesium bromide (manufactured by Aldrich, 1.0 mol / l diethyl ether solution) was added dropwise with a syringe, and after stirring for 2 hours, a saturated aqueous ammonium chloride solution was added for neutralization. This was dissolved in 100 ml of chloroform and allowed to stand in the dark for 12 hours. The obtained crude product was purified by silica gel column chromatography (developing solvent: chloroform: n-hexane = 1: 2) to obtain 244 mg (yield 32%) of the desired product as a reddish brown liquid. Formation of the target product was confirmed by mass spectrum and ESR. The synthesis was repeated to secure an amount necessary for manufacturing the photoelectric conversion element.

(2) Production of photoelectric conversion element using metal complex dye 10 g of acetonitrile (manufactured by Kanto Chemical Co., Ltd., special grade) was added to 2-phenyl-2- (4-chlorophenyl) -1,2-dihydroquinoline-1-oxyl. 6.4 g, 4.4 g of bis (trifluoromethanesulfonyl) imide lithium (manufactured by Wako Pure Chemical Industries, Ltd.), 225 mg of nitrosyltetrafluoroborate (manufactured by Aldrich), N- (n-butyl) benzimidazole (D. Kuang , C. Klein, S. Ito, J.-E. Moser, R. Humphry-Baker, N. Evans, F. Duriaux, C. Gratzel, SM Zakeeruddin, M. Gratzel, Adv. Mater. 19, 1133-1137 (Synthesized according to (2007)) 1 g was added to prepare an electrolytic solution (d).

A photoelectric conversion element was produced and evaluated in the same manner as in Example 2 except that the electrolytic solution (d) was used instead of the electrolytic solution (a). The obtained IV curve is shown in FIG. Table 3 shows the short-circuit current (I _SC ), open-circuit voltage (V _OC ), fill factor (FF), and photoelectric conversion efficiency (η) of the IV curve.

[Example 5]
(1) Induction from 6-methoxyquinoline to 6-methoxyquinoline-1-oxide 6.25 g (14.13 mmol) of 6-methoxyquinoline (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 200 ml of chloroform. Here, m-chloroperbenzoic acid (manufactured by Tokyo Chemical Industry Co., Ltd., purity 65%) 2.49 g (9.41 mmol) dissolved in 40 ml of chloroform was added, and the mixture was stirred for 12 hours. Further, 2.49 g (9.41 mmol) of m-chloroperbenzoic acid dissolved in 40 ml of chloroform was added, and stirring was continued for 12 hours. Thereafter, the mixture was neutralized by adding 250 ml of 1N aqueous sodium hydroxide solution. This was extracted with 50 ml of chloroform. The chloroform phase was collected and dried over anhydrous sodium sulfate. The solvent was removed to obtain 2.2 g (yield 88%) of the target product as a pale yellow solid. Formation of the target product was confirmed by mass spectrum and ¹ H-NMR.

(2) Induction from 6-methoxyquinoline-1-oxide to 2-phenyl-6-methoxyquinoline-1-oxide 777 mg (4.43 mmol) of dehydrated 6-methoxyquinoline-1-oxide was placed in a two-necked eggplant flask. And replaced with nitrogen. There, 50 ml of dehydrated tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd., for organic synthesis) was dissolved, and 8.36 ml of phenylmagnesium bromide (manufactured by Kanto Chemical Co., Ltd., 1.06 mol / l tetrahydrofuran solution) was syringed at room temperature. It was dripped at. After completion of the reaction, a saturated aqueous ammonium chloride solution was added for neutralization, and extraction was performed with chloroform. After washing three times with water, the chloroform phase was recovered and dried over anhydrous sodium sulfate. After removing the solvent, the resulting crude product was purified by silica gel column chromatography (developing solvent: ethyl acetate: hexane = 1: 2) to obtain 710 mg (yield: 64%) of the desired product as a pale yellow solid. Formation of the target product was confirmed by mass spectrum and ¹ H-NMR.

(3) Derivative dehydration of 2-phenyl-6-methoxyquinoline-1-oxide from 2-phenyl-6-methoxyquinoline-1-oxide to 2,2-diphenyl-1,2-dihydroquinoline-1-oxyl 300 mg (1.19 mmol) was placed in a 2-neck eggplant flask and purged with nitrogen. Thereto, 30 ml of dehydrated tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd., for organic synthesis) was dissolved, and 1.68 ml of phenylmagnesium bromide (manufactured by Kanto Chemical Co., Ltd., 1.06 mol / l tetrahydrofuran solution) was syringed at room temperature. It was dripped at. After completion of the reaction, a saturated aqueous ammonium chloride solution was added for neutralization, and extraction was performed with chloroform. After dehydration with anhydrous sodium sulfate, the solvent was removed with an evaporator. Next, this was dissolved in chloroform (special grade) and stirred at room temperature for 24 hours. Then, it refine | purified by neutral alumina column chromatography (developing solvent chloroform), and obtained 137 mg (yield 35%) of target objects of reddish brown solid. Formation of the target product was confirmed by mass spectrum and ESR. The synthesis was repeated to secure an amount necessary for manufacturing the photoelectric conversion element.

(4) Production of photoelectric conversion element using metal complex dye FTO glass Low-E (manufactured by Nippon Sheet Glass Co., Ltd.) was cut into a size of 3 cm × 3 cm with a diamond cutter, and 2-propanol (Wako Pure Chemical Industries, Ltd.) After being put into a special grade), ultrasonic cleaning was performed for 5 minutes. After taking out from the ultrasonic cleaner and drying, it was immersed in a 40 mM titanium chloride aqueous solution (a titanium chloride (IV) solution manufactured by Wako Pure Chemical Industries, Ltd. was used diluted) at 60 ° C. for 30 minutes. After wiping off the liquid on the surface, vacuum drying was performed for 1 hour. Titanium dioxide PST-18NR (manufactured by JGC Catalysts & Chemicals Co., Ltd.) was applied to the conductive surface of the glass substrate with a thickness of 15 μm by the doctor blade method and left at room temperature for 5 minutes. The coated glass substrate was placed on a 125 ° C. hot plate for 6 minutes, and baked at 325 ° C. for 5 minutes, 375 ° C. for 5 minutes, 450 ° C. for 15 minutes, and 500 ° C. for 15 minutes. In addition, although the color change was recognized at the initial stage of baking, it became transparent by raising temperature. After leaving to reach room temperature, titanium dioxide PST-400C (manufactured by JGC Catalysts & Chemicals Co., Ltd.) was further applied at a thickness of 20 μm and left at room temperature for 5 minutes. The coated glass substrate was placed on a 125 ° C. hot plate for 6 minutes, and baked at 325 ° C. for 5 minutes, 375 ° C. for 5 minutes, 450 ° C. for 15 minutes, and 500 ° C. for 15 minutes. Then, it was immersed for 30 minutes at 60 ° C. in a 40 mM titanium chloride aqueous solution (diluted and used titanium chloride (IV) solution manufactured by Wako Pure Chemical Industries, Ltd.). After wiping off the liquid on the surface, vacuum drying was performed for 1 hour. Leave to room temperature. The semiconductor layer was scraped off leaving a range of 1 cm × 1 cm at the center, then placed on a hot plate again, heated to 500 ° C., and allowed to stand for 30 minutes. Meanwhile, cis-bis (isothiocyanato) bis (2,2′-bipyridyl-4,4′-dicarboxylato) ruthenium (II) (manufactured by Aldrich) was dehydrated ethanol (manufactured by Kanto Chemical Co., Inc., for organic synthesis) And the concentration of the dye solution was adjusted to 0.2 mmol / l. When the heating of the hot plate was stopped and the temperature reached 80 ° C., it was immersed in the dye solution and allowed to stand for 24 hours to adsorb the dye to the semiconductor layer. Then, it vacuum-dried at room temperature for 1 hour, and produced the semiconductor electrode.

  Next, FTO glass (manufactured by Nishinoda Electric Co., Ltd.) with holes having a diameter of 1 mm in two places was placed in 2-propanol (manufactured by Wako Pure Chemical Industries, Ltd., special grade), and then ultrasonic cleaning was performed. Went for a minute. After wiping off the liquid on the surface, vacuum drying was performed for 1 hour. By a doctor blade method, platinum paste Platisol T / SP (manufactured by Solaronix) for preparing a transparent glass electrode was applied in a thickness corresponding to two scotch tapes (manufactured by 3M). This was left at room temperature for 40 minutes, placed on a hot plate, and baked at 350 ° C. for 5 minutes and at 450 ° C. for 15 minutes to obtain a counter electrode. The semiconductor electrode and the counter electrode were bonded to each other with an iron at 140 ° C. using Meltonix 1170-25 Series (manufactured by Solaronix) having a 1 cm × 1 cm hole for thermocompression bonding.

  Next, for acetonitrile (manufactured by Kanto Chemical Co., Ltd., special grade), 2,2-diphenyl-6-methoxy-1,2-dihydroquinoline-1-oxyl 0.1 mol / L, bis (trifluoromethanesulfonyl) imide Lithium (manufactured by Wako Pure Chemical Industries, Ltd.) 1.2 mol / L, nitrosyltetrafluoroborate (manufactured by Aldrich) 0.01 mol / L, N- (n-butyl) benzimidazole (D. Kuang, C. Klein, S. Ito, J.-E. Moser, R. Humphry-Baker, N. Evans, F. Duriaux, C. Gratzel, SM Zakeeruddin, M. Gratzel, Adv. Mater. 19, 1133-1137 (2007) ) Each was added so that it might become 0.5 mol / L, and electrolyte solution (e) was produced. The prepared electrolytic solution (e) was injected from a counter electrode hole with a microsyringe, and the hole was sealed with an adhesive tape to produce a photoelectric conversion element.

Evaluation was performed in the same manner as in Example 1 (3) except that this photoelectric conversion element was used. The obtained IV curve is shown in FIG. Table 4 shows the short-circuit current (I _SC ), open-circuit voltage (V _OC ), fill factor (FF), and photoelectric conversion efficiency (η) of the IV curve.

[Example 6]
(1) Induction from 4-iodoaniline to benzylidene- (4-iodoaniline) 4-iodoaniline (manufactured by Tokyo Chemical Industry Co., Ltd., first grade) 8.0 g (37 mmol) was added to 50 ml of toluene (Kanto Chemical Co., Ltd.) ), Special grade). To this was added 3.87 g (90.5 mmol) of distilled benzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.), refluxed for 30 minutes, and then allowed to cool. n-Hexane was added and the precipitated crude crystals were separated by filtration and further washed with n-hexane. 11.0 g of the target product was obtained as a yellow solid (yield 98%). Formation of the target product was confirmed by mass spectrum and ¹ H-NMR.

(2) Derivation of benzylidene- (4-iodoaniline) to 2-phenyl-4-ethoxy-6-iodo-1,2,3,4-tetrahydroquinoline 3.0 g of benzylidene- (4-iodoaniline) (9 .8 mmol) was dissolved in 15 ml of toluene (manufactured by Kanto Chemical Co., Ltd., special grade). Distilled ethyl vinyl ether (Tokyo Chemical Industry Co., Ltd., first grade) 1.88 mL (19.5 mmol) and boron trifluoride etherate (Kanto Chemical Co., Ltd.) 41 μL (0.33 mmol) were added and refluxed for 2 hours. . Then, it returned to room temperature, neutralized with the 10 weight% sodium hydroxide aqueous solution, chloroform was added, and the organic phase was collect | recovered after liquid separation. After removing the solvent, the residue was purified by silica gel column chromatography (developing solvent: chloroform) to obtain 1.9 g of a tan liquid (yield 51%). Formation of the target product was confirmed by mass spectrum and ¹ H-NMR.

(3) Induction of 2-phenyl-4-ethoxy-6-iodo-1,2,3,4-tetrahydroquinoline to 2-phenyl-6-iodoquinoline 2-phenyl-4-ethoxy-6- 1.9 g (2.5 mmol) of iodo-1,2,3,4-tetrahydroquinoline and 10 ml of toluene (manufactured by Kanto Chemical Co., Ltd., special grade) were added and dissolved. At room temperature, 2.2 ml (5 mmol) of diethyl azodicarboxylate (Tokyo Chemical Industry Co., Ltd., 40% toluene solution) was added and refluxed for 12 hours. The mixture was neutralized with an aqueous potassium hydroxide solution and the organic phase was recovered after chloroform separation. After dehydration with anhydrous sodium sulfate, the solvent was removed, and the resulting crude product was purified by silica gel column chromatography (developing solvent: chloroform) to obtain 1.1 g of light yellow solid (yield 65%). It was. Formation of the target product was confirmed by mass spectrum and ¹ H-NMR.

(4) Derivation of 2-phenyl-6-iodoquinoline from 2-phenyl-6- (2,2,2-trifluoroethoxy) quinoline To 500 mg (1.5 mmol) of 2-phenyl-6-iodoquinoline, Fluoroethanol (manufactured by Wako Pure Chemical Industries, Ltd.) 30 mL (420 mmol) was added, and copper iodide (manufactured by Kanto Chemical Co., Ltd.) 150 mg (0.79 mmol), cesium carbonate (manufactured by Kanto Chemical Co., Ltd., special grade) 4.2 g (12 mmol) and 250 μL (1.57 mmol) of ethyl 2-oxocyclohexacarboxylate (manufactured by Tokyo Chemical Industry Co., Ltd.) were added and refluxed for 14 hours. Dichloromethane and water were added, and after liquid separation, the organic phase was recovered. After dehydration with anhydrous sodium sulfate, the solvent was removed, and the resulting crude product was purified by silica gel column chromatography (developing solvent: chloroform: n-hexane = 5: 1) to give a white solid (210 mg, yield 57). %). Formation of the target product was confirmed by mass spectrum and ¹ H-NMR.

(5) Derivation of 2-phenyl-6- (2,2,2-trifluoroethoxy) quinoline to 2-phenyl-6- (2,2,2-trifluoroethoxy) quinoline-1-oxide m-chloro A solution prepared by dissolving 90 mg (0.3 mmol) of perbenzoic acid (manufactured by Tokyo Chemical Industry Co., Ltd., purity 65%) in 2 ml of chloroform was ice-cooled, and the same ice-cooled 2-phenyl-6- (2,2, The mixture was added dropwise to 10 ml of chloroform containing 100 mg (0.3 mmol) of 2-trifluoroethoxy) quinoline and stirred for 24 hours. Further, after 15 hours, 2 ml of a chloroform solution in which 90 mg (0.3 mmol) of m-chloroperbenzoic acid was dissolved was added and stirred for 30 hours. Then, 10 ml of 1N sodium hydroxide aqueous solution was added and neutralized. After washing three times with water, the chloroform phase was recovered and dried over anhydrous sodium sulfate. After removing the solvent, the resulting crude product was purified by silica gel column chromatography (developing solvent: chloroform) to obtain 93 mg (yield 88%) of the target product as a yellowish white solid. Formation of the target product was confirmed by mass spectrum and ¹ H-NMR.

(6) From 2-phenyl-6- (2,2,2-trifluoroethoxy) quinoline-1-oxide to 2,2-diphenyl-6- (2,2,2-trifluoroethoxy) -1,2- Induction to dihydroquinoline-1-oxyl 80 mg of 2-phenyl-6- (2,2,2-trifluoroethoxy) quinoline-1-oxide dehydrated with diphosphorus pentoxide (Kanto Chemical Co., Ltd., first grade) (0.25 mmol) was placed in a 2-neck eggplant flask and purged with nitrogen. It is dissolved in 5 ml of dehydrated tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd., for organic synthesis), and 0.5 ml of phenylmagnesium bromide (manufactured by Kanto Chemical Co., Ltd., 1 mol / l tetrahydrofuran solution) is added dropwise thereto with a syringe at room temperature. Stir for hours. After the reaction, a saturated aqueous ammonium chloride solution was added for neutralization. This was dissolved in 100 ml of chloroform and allowed to stand in the dark for 12 hours. After drying over anhydrous sodium sulfate and removing the solvent, the resulting crude product was purified by silica gel column chromatography (developing solvent: chloroform) to obtain 49 mg (yield 49%) of the desired product as a shiny reddish brown solid. . Formation of the target product was confirmed by mass spectrum, elemental analysis, and ESR. The synthesis was repeated to secure an amount necessary for manufacturing the photoelectric conversion element.

Next, 0.1 mol of 2,2-diphenyl-6- (2,2,2-trifluoroethoxy) -1,2-dihydroquinoline-1-oxyl with respect to acetonitrile (manufactured by Kanto Chemical Co., Ltd., special grade) / L, bis (trifluoromethanesulfonyl) imide lithium (Wako Pure Chemical Industries, Ltd.) 1.2 mol / L, nitrosyltetrafluoroborate (Aldrich) 0.01 mol / L, N- (n-butyl) benz Imidazole (D. Kuang, C. Klein, S. Ito, J.-E. Moser, R. Humphry-Baker, N. Evans, F. Duriaux, C. Gratzel, SM Zakeeruddin, M. Gratzel, Adv. Mater. 19, 1133-1137 (2007)), each was added so as to be 0.5 mol / L to prepare an electrolytic solution (f).
A photoelectric conversion element was produced and evaluated in the same manner as in Example 5 except that the electrolytic solution (f) was used instead of the electrolytic solution (e). The obtained IV curve is shown in FIG. Table 4 shows the short-circuit current (I _SC ), open-circuit voltage (V _OC ), fill factor (FF), and photoelectric conversion efficiency (η) of the IV curve.

  According to the present invention, it is possible to provide a photoelectric conversion element in which the electrolyte layer has low corrosivity and excellent photoelectric conversion efficiency, and a π-conjugated organic radical compound constituting the photoelectric conversion element. Further, the π-conjugated stable organic radical compound of the present invention can be applied to various organic devices. For example, it is expected to be used for organic electroluminescence elements, organic solar cells, organic transistors, organic memories, quantum computers, and the like.

DESCRIPTION OF SYMBOLS 110 Photoelectric conversion element 120 Semiconductor electrode 121 Semiconductor layer 122 Transparent conductive layer 123 Electrode base material 130 Electrolyte layer 140 Counter electrode 150 Sealing material

Claims (4)

A photoelectric conversion element comprising a semiconductor electrode containing a semiconductor layer and a dye, a counter electrode, and an electrolyte layer provided between the semiconductor electrode and the counter electrode, wherein the electrolyte layer has the following general formula (1 The said photoelectric conversion element containing the (pi) conjugated organic radical compound shown by this.

(In the formula (1), the substituents represented by X ¹ , X ² , X ³ , X ⁴ , and X ⁵ are each independently an electron-withdrawing group, hydrogen, an alkyl group having 1 to 6 carbon atoms, carbon It is either an alkoxy group having 1 to 6 carbon atoms or a fluorine-substituted alkoxy group having 1 to 6 carbon atoms.) In the general formula (1), at least one of the substituents represented by X ¹ , X ² , X ³ , X ⁴ , and X ⁵ is an electron-withdrawing group, and the remaining substituents are independent of each other. The photoelectric conversion element according to claim 1, which is hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a fluorine-substituted alkoxy group having 1 to 6 carbon atoms. The electron-withdrawing group is a group independently selected from the group consisting of F, Cl, NO ₂ , CN, C ₆ F ₅ , and C _n F _{2n + 1} (n is an integer of 1 to 6). 2. The photoelectric conversion element according to 2.   The photoelectric conversion element according to claim 1, wherein the dye is a metal complex dye.