JP2014207156A - Photoelectric conversion element, dye-sensitized solar cell, metal complex dye, dye solution, dye-adsorbed electrode, and method for manufacturing dye-sensitized solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a photoelectric conversion element improved in spectral sensitivity characteristic in a long wavelength region, and superior in photoelectric conversion efficiency and durability; a dye-sensitized solar cell; a metal complex dye used therefor; a dye solution, a dye-adsorbed electrode; and a method for manufacturing a dye-sensitized solar cell.SOLUTION: A photoelectric conversion element comprises: a conductive support member; a photosensitive layer including an electrolyte; a charge transfer layer including an electrolyte; and a counter electrode. The photosensitive layer has semiconductor microparticles supporting a metal complex dye expressed by the formula (I). Also, provided are a metal complex used therefor, a metal complex dye, a dye solution, a dye-adsorbed electrode, and a dye-sensitized solar cell, a manufacturing method thereof. M(LD)(LA)(LX) (Y)n Formula (I)[In the formula, M represents a metal ion.]

Description

  The present invention relates to a photoelectric conversion element, a dye-sensitized solar cell, a metal complex dye, a dye solution, a dye-adsorbing electrode, and a method for producing a dye-sensitized solar cell.

  Photoelectric conversion elements are used in various optical sensors, copying machines, solar cells, and the like. Various types of photoelectric conversion elements have been put to practical use, such as those using metals, semiconductors, organic pigments and dyes, or combinations thereof. In particular, a solar cell using non-depleting solar energy does not require fuel, and full-scale practical use is highly expected as it uses inexhaustible clean energy. Among them, silicon-based solar cells have been researched and developed for a long time, and are spreading due to the policy considerations of each country. However, since silicon is an inorganic material, there is a limit to improving throughput and cost.

  Therefore, research on dye-sensitized solar cells has been vigorously conducted. In particular, it was the research result of Graetzel et al. (See Patent Document 1) of Lausanne University of Technology, Switzerland. They adopted a structure in which a dye composed of a ruthenium complex was fixed on the surface of a porous titanium oxide thin film, realizing conversion efficiency comparable to that of amorphous silicon. As a result, dye-sensitized solar cells that can be manufactured without using an expensive vacuum apparatus have attracted attention from researchers all over the world.

To date, dyes generally called N3, N719, Z907, and J2 have been developed as metal complex dyes used in photoelectric conversion elements.
As a long-wave ruthenium complex, a “black dye” having a terpyridine ligand is known (Patent Document 1). Recently, for the purpose of improving spectral sensitivity characteristics in the long wavelength region of visible light, a terpyridine ligand is known. Numerous ruthenium metal complex dyes have been proposed (see Patent Document 2 or Non-Patent Document 1).

Japanese Patent No. 4298799 US Patent Application Publication No. 2010/0258175

Angew. Chem. Int. Ed. , 51, 752

The dyes described in Patent Documents 1 and 2 and Non-Patent Document 1 are not always satisfactory in terms of spectral sensitivity characteristics and photoelectric conversion efficiency in the long wavelength region at wavelengths of 800 to 850 nm. Improvement was desired.
In view of the above situation, the present invention provides a photoelectric conversion element that improves the photoelectric conversion efficiency by improving the spectral sensitivity characteristic in the long wavelength region in the absorption characteristic of the metal complex dye, and has excellent durability. It is an object of the present invention to provide a dye-sensitized solar cell, a metal complex dye used for the dye-sensitized solar cell, a dye solution, a dye-adsorbing electrode, and a method for producing a dye-sensitized solar cell.

Since the conventional metal complex dyes are not necessarily sufficient for spectral sensitivity characteristics in the long wavelength region, the present inventors have found that spectral sensitivity characteristics in the long wavelength region, particularly sensitivity characteristics at 800 to 850 nm, that is, quantum yield. Various improvement of (IPCE) was examined.
As a result, as a ligand used together with a tridentate ligand having a function of adsorbing to the surface of the semiconductor fine particles, a nitrogen atom coordinated by a lone pair with respect to the central metal ion and an anion with respect to the central metal ion In the bidentate ligand formed by combining a nitrogen atom, an oxygen atom, or a sulfur atom as a coordinating atom to coordinate, the above-described nitrogen atom coordinated by a lone electron pair to the central metal is However, when the ring-constituting atoms constituting a nitrogen-containing aromatic ring having a further electron deficiency that further includes atoms having a strong electron withdrawing property are effective in improving the spectral sensitivity characteristics in the long wavelength region of the photoelectric conversion element. I found out. Moreover, it has been found that such a bidentate ligand can improve not only the spectral sensitivity characteristic but also the durability of the photoelectric conversion element.
Based on these findings, the inventors have further studied and have come to make the present invention.

  That is, the subject of this invention was achieved by the following means.

(1) A photoelectric conversion element having a conductive support, a photoreceptor layer containing an electrolyte, a charge transfer layer containing an electrolyte, and a counter electrode,
The photoelectric conversion element in which this photoreceptor layer has the semiconductor fine particle by which the metal complex dye represented by following formula (I) was carry | supported.
M (LD) (LA) (LX) · (Y) n Formula (I)
[Wherein, M represents a metal ion.
LD represents a bidentate ligand represented by any of the following formulas (2L-1) to (2L-3).
LA represents a tridentate ligand represented by the following formula (AL-1) or (AL-2).
LX represents a monodentate ligand.
Y represents a counter ion necessary for neutralizing the electric charge. n represents an integer of 0 to 4. ]

[In the formula, * represents a bonding position to the metal ion M.
Ring D ¹ represents a nitrogen-containing aromatic ring, ring D ² represents an aromatic hydrocarbon ring or heteroaromatic ring. A ¹² and ^{A 13} are each ^{independently, N - R L,} O - or S ^- represents a. A ^{1 to} A ⁴ each independently represent CR ^LD or N, and at least one of A ^{1 to} A ⁴ represents N. L ^LD is -C (= O)-, -C (= S)-, -C (= NR ^L )-, -C (R ^L ) ₂ -and -C (= C (R ^L ) ₂ )- Represents a divalent linking group selected from the group consisting of R ^L and R ^LD each independently represent a hydrogen atom or a substituent that does not have the following Anc ¹ , Anc ^2, and Anc ³ . ]

[Wherein, Anc ^{1 to} Anc ³ each independently represent —CO ₂ H, —SO ₃ H, —PO ₃ H ₂ or a group in which any one of these protons is dissociated. R ^AL represents a substituent other than Anc ^{1 to} Anc ³ , and b1 represents an integer of 0 to 4. ]

(2) The photoelectric conversion element according to (1), wherein the M is Fe ²⁺ , Ru ²⁺ or Os ²⁺ .
(3) The photoelectric conversion element according to (1) or (2), wherein ^{1 to} 3 of the A ^{1 to} A ⁴ are N.
(4) In the formulas (2L-1) to (2L-3), represented by the following formula (2L _R ) formed by including the nitrogen atom bonded to the metal ion M and the A ^{1 to} A ^4. ring structure is the following formula _{(2L R -1) ~ (2L} R -4) a cyclic structure represented by any one of (1) to (3) the photoelectric conversion device according to any one of .

[Wherein, R ^LDa represents a substituent not having the above Anc ¹ , Anc ² and Anc ³ , nL1 to nL3 each independently represents an integer of 0 to 3, and nL4 represents an integer of 0 to 2. ]

(5) The photoelectric conversion element according to any one of (1) to (4), wherein a co-adsorbent having one or more acidic groups is further supported on the semiconductor fine particles.
(6) The photoelectric conversion element according to (5), wherein the adsorbent is represented by the following formula (CA).

[Wherein, R ^A1 represents a substituent having an acidic group. R ^A2 represents a substituent. nA represents an integer of 0 or more. ]

(7) A dye-sensitized solar cell having the photoelectric conversion element according to any one of (1) to (6).
(8) A metal complex dye represented by the following formula (I).
M (LD) (LA) (LX) · (Y) n Formula (I)
[Wherein, M represents a metal ion.
LD represents a bidentate ligand represented by any of the following formulas (2L-1) to (2L-3).
LA represents a tridentate ligand represented by the following formula (AL-1) or (AL-2).
LX represents a monodentate ligand.
Y represents a counter ion necessary for neutralizing the electric charge. n represents an integer of 0 to 4. ]

[In the formula, * represents a bonding position to the metal ion M.
Ring D ¹ represents a nitrogen-containing aromatic ring, ring D ² represents an aromatic hydrocarbon ring or heteroaromatic ring. A ¹² and ^{A 13} are each ^{independently, N - R L,} O - or S ^- represents a. A ^{1 to} A ⁴ each independently represent CR ^LD or N, and at least one of A ^{1 to} A ⁴ represents N. L ^LD is -C (= O)-, -C (= S)-, -C (= NR ^L )-, -C (R ^L ) ₂ -and -C (= C (R ^L ) ₂ )- Represents a divalent linking group selected from the group consisting of R ^L and R ^LD each independently represent a hydrogen atom or a substituent that does not have the following Anc ¹ , Anc ^2, and Anc ³ . ]

[Wherein, Anc ^{1 to} Anc ³ each independently represent —CO ₂ H, —SO ₃ H, —PO ₃ H ₂ or a group in which any one of these protons is dissociated. R ^AL represents a substituent other than Anc ^{1 to} Anc ³ , and b1 represents an integer of 0 to 4. ]

(9) In the formulas (2L-1) to (2L-3), the following ring structure (2L _R ) formed including the nitrogen atom bonded to the metal ion M and the A ^{1 to} A ⁴ , the following equation _{(2L R -1) ~ (2L} R -4) metal complex dye according to a ring structure represented by any one (8) of the.

[Wherein, R ^LDa represents a substituent not having the above Anc ¹ , Anc ² and Anc ³ , nL1 to nL3 each independently represents an integer of 0 to 3, and nL4 represents an integer of 0 to 2. ]

(10) A dye solution obtained by dissolving the metal complex dye described in (8) or (9).
(11) The dye solution according to (10), wherein 0.001 to 0.1% by mass of the metal complex dye is contained in an organic solvent, and water is suppressed to 0.1% by mass or less.
(12) The dye solution according to (10) or (11), wherein the dye solution further contains a co-adsorbent having one or more acidic groups.
(13) The dye solution according to (12), wherein the co-adsorbent is represented by the following formula (CA).

[Wherein, R ^A1 represents a substituent having an acidic group. R ^A2 represents a substituent. nA represents an integer of 0 or more. ]

(14) A semiconductor is coated on a conductive support with a composition obtained from the dye solution described in any one of (10) to (13), and the coated composition is cured to be photosensitive. A dye-adsorbing electrode for a dye-sensitized solar cell as a body layer.
(15) A method for producing a dye-sensitized solar cell in which the dye-adsorbing electrode, the electrolyte, and the counter electrode according to (14) are prepared and assembled using these.

In the present specification, unless otherwise specified, the carbon-carbon double bond may be either E-type or Z-type in the molecule or a mixture thereof. When there are a plurality of substituents, linking groups, ligands, etc. (hereinafter referred to as substituents, etc.) indicated by a specific code, or when a plurality of substituents etc. are specified simultaneously or alternatively, a special notice is given. As long as there is no, each substituent etc. may mutually be same or different. The same applies to the definition of the number of substituents and the like. Further, when a plurality of substituents and the like are close to each other (especially when they are adjacent to each other), they may be connected to each other to form a ring unless otherwise specified. In addition, a ring such as an alicyclic ring, an aromatic ring, or a hetero ring may be further condensed to form a condensed ring.
In the present invention, each substituent may be further substituted with a substituent unless otherwise specified.

  According to the present invention, in the absorption characteristic of the metal complex dye, the photoelectric conversion efficiency is improved by improving the spectral sensitivity characteristic in the long wavelength region, and in addition, the photoelectric conversion element excellent in durability, the dye-sensitized solar cell, It is possible to provide a method for producing a metal complex and a metal complex dye, a dye solution, a dye-adsorbing electrode, and a dye-sensitized solar cell used for this.

It is sectional drawing typically shown including the enlarged view of the circular part in a layer about one embodiment of the photoelectric conversion element of this invention. It is sectional drawing which shows typically the dye-sensitized solar cell of another embodiment of the photoelectric conversion element of this invention.

  The photoelectric conversion element of the present invention has a conductive support, a photoreceptor layer containing an electrolyte, a charge transfer body layer containing an electrolyte, and a counter electrode. This photoreceptor layer has semiconductor fine particles carrying a metal complex dye represented by the following formula (I).

<< metal complex dye >>
The metal complex dye of the present invention is represented by the following formula (I).
M (LD) (LA) (LX) · (Y) n Formula (I)
[Wherein, M represents a metal ion.
LD represents a bidentate ligand represented by any of the following formulas (2L-1) to (2L-3).
LA represents a tridentate ligand represented by the following formula (AL-1) or (AL-2).
LX represents a monodentate ligand.
Y represents a counter ion necessary for neutralizing the electric charge. n represents an integer of 0 to 4. ]

[In the formula, * represents a bonding position to the metal ion M.
Ring D ¹ represents a nitrogen-containing aromatic ring, ring D ² represents an aromatic hydrocarbon ring or heteroaromatic ring. A ¹² and ^{A 13} are each ^{independently, N - R L,} O - or S ^- represents a. A ^{1 to} A ⁴ each independently represent CR ^LD or N, and at least one of A ^{1 to} A ⁴ represents N. L ^LD is -C (= O)-, -C (= S)-, -C (= NR ^L )-, -C (R ^L ) ₂ -and -C (= C (R ^L ) ₂ )- Represents a divalent linking group selected from the group consisting of R ^L and R ^LD each independently represent a hydrogen atom or a substituent that does not have the following Anc ¹ , Anc ^2, and Anc ³ . ]

[Wherein, Anc ^{1 to} Anc ³ each independently represent —CO ₂ H, —SO ₃ H, —PO ₃ H ₂ or a group in which any one of these protons is dissociated. R ^AL represents a substituent other than Anc ^{1 to} Anc ³ , and b1 represents an integer of 0 to 4. ]

− Metal ion M −
M is a central metal ion of a metal complex dye, and examples of these metals include elements of groups 6 to 12 of the long-period periodic table.
Specific examples of such elements include Ru, Fe, Os, Cu, W, Cr, Mo, Ni, Pd, Pt, Co, Ir, Rh, Re, Mn, and Zn.
In the present invention, M is preferably Os ²⁺ , Ru ²⁺ or Fe ²⁺ , and particularly preferably Ru ²⁺ ion.
Note that in a state of being incorporated in the photoelectric conversion element, the valence of M may change due to an oxidation-reduction reaction with surrounding materials.

− Ligand LD −
In the present invention, the ligand LD is a ligand that binds to the metal ion M in a bidentate, and is classified as a donor ligand. The ligand LD is coordinated to the metal ion M by a nitrogen atom having a lone electron pair and an anion. The nitrogen atom having a lone electron pair is a nitrogen atom coordinated to the metal ion M by this lone electron pair, and further includes an atom having a stronger electron withdrawing property than a carbon atom, and is an electron deficient formula described later. a ring-constituting nitrogen atom constituting the nitrogen-containing aromatic ring represented by (2L _R).
The anion that coordinates to the metal ion M is a nitrogen anion, an oxygen atom anion, or a sulfur anion.

Here, the lone electron pair is an electron pair (a set of two electrons) that does not participate in a covalent bond among the outermost electron pairs of the nitrogen atom, and the nitrogen atom has one pair of the lone electron pair.
A nitrogen atom, an oxygen atom, or a sulfur atom is an anion,> N ⁻ , —O ⁻ , or —S ⁻ , while having a lone pair of electrons as it is, but an atom coordinated to the metal ion M is more than a lone electron. The anion is also preferred. Therefore, in the present invention, an anion of a nitrogen atom, an oxygen atom, or a sulfur atom is regarded as a coordination atom that coordinates to the metal ion M as an anion even if it has a lone pair of electrons as it is.
For example,> NH, —OH, and —SH are all those in which a hydrogen atom is not dissociated, that is, an anion does not form an anion, and there is a thing that coordinates with the metal ion M by each lone pair. In the present invention, as the stable coordination structure, the anion is regarded as a coordination atom. That is, the> NH, -OH, the case of ^{-SH,> N -, -O -} , -S - regarded as the anion is coordinated.

  Based on the above, a nitrogen atom coordinated by a lone electron pair is a nitrogen atom having no hydrogen atom.

On the other hand, the atom whose coordination atom is an anion is a nitrogen atom, an oxygen atom and a sulfur atom, and a nitrogen atom is preferable. These atoms may be ring-constituting atoms or atoms contained in a simple group (substituent, preferably an atom in a substituent that is substituted with a ring structure). Particularly, in the case of a nitrogen atom, it can be a ring constituent atom constituting a heteroaromatic ring, and such a heterocyclic constituent atom is preferable.
In the present invention, each atom serving as an anion is preferably a heterocyclic atom or a substituent on the ring. Further, this ring is preferably an aromatic hydrocarbon ring or a heteroaromatic ring, and the heteroaromatic ring is a nitrogen-containing heteroaromatic ring (including a heteroaromatic ring having a heteroatom other than a nitrogen atom). Further preferred.

Such bidentate ligand LD is specifically represented by any of the following formulas (2L-1) to (2L-3).

In the formula, * represents a bonding position to the metal ion M.
Ring D ¹ represents a nitrogen-containing aromatic ring, ring D ² represents an aromatic hydrocarbon ring or heteroaromatic ring.
A ¹² and ^{A 13} are each ^{independently, N - R L,} O - or S ^- represents a.
A ^{1 to} A ⁴ each independently represent CR ^LD or N, and at least one of A ^{1 to} A ⁴ represents N.
L ^LD is -C (= O)-, -C (= S)-, -C (= NR ^L )-, -C (R ^L ) ₂ -and -C (= C (R ^L ) ₂ )- Represents a divalent linking group selected from the group consisting of
R ^L and R ^LD each independently represent a hydrogen atom or a substituent that does not have the following Anc ¹ , Anc ^2, and Anc ³ .

  When such a ligand LD is used in combination with a ligand LA and a ligand LX described later, the photoelectric conversion efficiency and durability in the long wavelength region are increased.

In the formula (2L-1), the ring D ¹ has an active hydrogen on at least one nitrogen atom of the nitrogen-containing aromatic ring, and the —NH— moiety becomes an anion —N ⁻ —. And a nitrogen-containing aromatic ring that can be bonded to the metal ion M. Accordingly, —N ⁻ — on ring D ¹ in formula (2L-1) is a nitrogen anion from which a hydrogen atom bonded to a nitrogen atom constituting ring D ¹ is eliminated.
Such a nitrogen-containing aromatic ring is preferably a 5- to 7-membered ring and may be condensed. For example, an imidazole ring, a triazole ring, a tetrazole ring, a benzimidazole ring, a 1H-indazole ring, a purine ring, a pyrrole ring, a pyrazole ring in which the atom bonded to the metal ion M is a nitrogen atom at the 1-position, and the like are listed. , A triazole ring, a tetrazole ring, a pyrrole ring, and a pyrazole ring in which the atom bonded to the metal ion M is a nitrogen atom at the 1-position is preferable. Among these, the nitrogen-containing aromatic ring is preferably a group represented by the following formulas (a-1) to (a-6) derived from an imidazole ring, a pyrazole ring, a triazole ring, a tetrazole ring or a pyrrole ring. , (A-1), (a-2) or a group represented by (a-5) is more preferred, and a group represented by (a-2) is particularly preferred.

  In the formula, Rd represents a substituent. b1 represents an integer of 0 to 2, b2 represents an integer of 0 to 3, and b3 represents 0 or 1, respectively. When b1 is 2 or b2 is 2 or more, a plurality of Rd's may be bonded to each other to form a ring. Examples of Rd include a substituent T described later.

  Here, in the formulas (a-1) to (a-5), groups including the following structures are included when the adjacent Rds form a ring.

  In the formula, Rd and b1 to b3 have the same meanings as Rd and b1 to b3 in the formulas (a-1) to (a-5) described above, and preferred ranges are also the same. b4 represents an integer of 0 to 4, and b5 represents an integer of 0 to 5. In formulas (a-1a) and (a-1b), Rd represents not only a benzene ring but also a pyrrole ring.

  Rd is preferably a linear or branched alkyl group, a cycloalkyl group, an alkenyl group, a fluoroalkyl group, an aryl group, a halogen atom, an alkoxycarbonyl group, a cycloalkoxycarbonyl group, or a group formed by combining these, more preferably A straight chain or branched alkyl group, a cycloalkyl group, an alkenyl group, a fluoroalkyl group, an aryl group or a group formed by combining these, particularly preferably a linear or branched alkyl group, a cycloalkyl group, an alkenyl group, a fluoro group. An alkyl group and a group formed by a combination thereof.

Rd preferably does not have an adsorbing group that adsorbs to the surface of the semiconductor fine particles. The adsorbing group adsorbed on the surface of the semiconductor fine particles refers to groups represented by Anc ^{1 to} Anc ³ in the ligand LA described later. Even if Rd contains a group corresponding to the adsorbing group, it is included as a group that binds to the metal ion M and is not adsorbed on the surface of the semiconductor fine particles.

In the formula (2L-1), A ^{1 to} A ⁴ each independently represent CR ^LD (R ^LD is a hydrogen atom or a substituent not having the following Anc ¹ , Anc ^2, and Anc ³ ) or N, and A ¹ At least one of the to a ⁴ represents N. That is, the ring structure represented by the formula (2L _R ) described later formed by including a ring-constituting nitrogen atom coordinated to the metal ion M by a lone pair and A ^{1 to} A ⁴ has six ring structures. It has 2 to 5 nitrogen atoms among the atoms. Thus, a ring structure formed by including a plurality of nitrogen atoms having electron withdrawing properties stronger than carbon atoms as ring constituent atoms becomes a nitrogen-containing aromatic ring having fewer electrons than a pyridine ring structure. When such a nitrogen-containing aromatic ring is coordinated to the metal ion M by a lone pair of nitrogen atoms constituting the ring, in combination with the ligands LA and LX described later, the length of the photoelectric conversion element Both spectral sensitivity characteristics and durability in the wavelength region can be improved.
From the viewpoint of improving spectral sensitivity characteristics and durability, it is preferable that 1 to 3 of A ^{1 to} A ⁴ are N, and it is more preferable that 1 or 2 is N.
Such a nitrogen-containing aromatic ring has two or more N as ring constituent atoms and does not have a nitrogen atom that becomes an anion. For example, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a triazine Preferable examples include a ring, a tetrazine ring, and a ring in which benzene is condensed.

Table ring structure in Formula (2L-1), i.e., the ring structure represented by the following formula (2L _R) is specifically by any one of the following formulas _{(2L R -1) ~ (2L} R -4) is preferably a ring structure that is, more preferably the ring structure represented by any one of formula _{(2L R -1) ~ (2L} R -3).

In the formula, R ^LDa is a substituent that does not have the following Anc ^{1 to} Anc ³ .

Examples of the substituent R ^LD and the substituent R ^LDa include the substituent T described later. Among these, alkyl groups, alkenyl groups, alkynyl groups, cycloalkyl groups, cycloalkenyl groups, aryl groups, heterocyclic groups, alkoxy groups, alkenyloxy groups, alkynyloxy groups, cycloalkyloxy groups, aryloxy groups, heterocyclic rings An oxy group, an amino group, an alkylthio group, a cycloalkylthio group, an arylthio group, a heteroarylthio group, a polyalkylene ether group, and a halogen atom are preferable, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, an alkoxy group, An aryloxy group, an amino group, an alkylthio group, and an arylthio group are more preferable, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, an amino group, an alkylthio group, and an arylthio group are more preferable, and an alkyl group, an alkenyl group, Rukiniru group, an aryl group, a heterocyclic group is particularly preferred.
The substituents of the substituents R ^LD and R ^LDa may be a group formed by combining a plurality of the above-described substituents. For example, as a group bonded to the ring structure, an alkyl group, an alkenyl group, an alkynyl group, an aryl group A group selected from the group consisting of a heterocyclic group, an aryloxy group and an alkylthio group, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, an aryloxy group, an alkylthio group, an amino group and a cycloalkyl group And a group to which at least one selected from the group consisting of is bonded.
In addition, the substituent of R ^LD and R ^LDa is not an anionic functional group but includes an anion in part because it facilitates the coordination of the ring nitrogen atom to the metal ion M with a lone electron pair. Preferably not.
In the formula, nL1 to nL3 are each independently an integer of 0 to 3, and nL4 is an integer of 0 to 2. nL1 to nL3 are each preferably an integer of 0 to 2, and nL1 to nL4 are particularly preferably 0 or 1, and most preferably 1.

In the formula (2L-2), the ring D ² is an aromatic hydrocarbon ring or heteroaromatic ring, 5-7 membered ring is preferred, may be condensed. Examples of the aromatic hydrocarbon ring include an aromatic ring group corresponding to the aryl group of the substituent T described later, and examples of the heteroaromatic ring include a heterocyclic group corresponding to the heterocyclic group of the substituent T described later. Among these, as the aromatic hydrocarbon ring or heteroaromatic ring, a benzene ring, a naphthalene ring, a thiophene ring, a furan ring, a pyridine ring, a pyrazole ring, and a pyrrole ring are preferable, and a benzene ring is particularly preferable.
A ^{12 is,} N ^- R L, O ^- or S ^- a and is present as a substituent on the ring D2 (substituted) amino group, the same meanings as residues obtained by removing active hydrogen from hydroxyl or thiol group. Among them, the after A ¹² is coordinated to the metal ion M, basic lone pairs remaining on A ¹² to not participate in the coordination bond is sufficiently small, A ¹² by the addition of a proton O ⁻ and S ⁻ are preferable, and O ⁻ is more preferable in that it is less likely to become H ⁺ and is more excellent in the absorption characteristics in the long wavelength region of the absorption characteristics.
R ^L is a hydrogen atom or a substituent that does not have the following Anc ^{1 to} Anc ³ , and examples thereof include a substituent T described later. Among these, alkyl groups, alkenyl groups, alkynyl groups, cycloalkyl groups, cycloalkenyl groups, aryl groups, heterocyclic groups, alkoxy groups, alkenyloxy groups, alkynyloxy groups, cycloalkyloxy groups, aryloxy groups, heterocyclic rings An oxy group, a (substituted or unsubstituted) amino group, an alkylthio group, a cycloalkylthio group, an arylthio group, and a halogen atom are preferable, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, an alkoxy group, an aryloxy group, (Substituted or unsubstituted) amino group, alkylthio group, and arylthio group are more preferred, and alkyl group, alkenyl group, alkynyl group, aryl group, heterocyclic group, (substituted or unsubstituted) amino group, alkylthio group, and arylthio group are further included. Preferably an alkyl group, Kenyir group, an alkynyl group, an aryl group, a heterocyclic group, (substituted or unsubstituted) amino group particularly preferred. Examples of the substituted amino group include —NHSO ₂ Ry (Ry represents an alkyl group). Specific examples of —NHSO ₂ Ry include —NHSO ₂ CH ₃ , —NHSO ₂ C ₂ H ₅ , —NHSO ₂ C ₃ H _{7 and the} like.
Ring D ² may further have a substituent T in addition to A ¹² . Incidentally, the substitution position o, m and p of the benzene rings represent the position relative to ^{A 12.}
The ring structure in Formula (2L-2) is synonymous with the ring structure in Formula (2L-1), and preferred ones are also the same.

In the formula (2L-3), the divalent linking group L ^LD is -C (= O)-, -C (= S)-, -C (= NR ^L )-, -C (R ^L ) _2-. And a divalent linking group selected from the group consisting of —C (═C (R ^L ) ₂ ) —, among these, the stability of the anion of A ¹³ is high, and the durability of the complex after coordination -C (= O)-, -C (= S)-, -C (= NR ^L )-are preferable, and -C (= O)-, -C (= S)- Is more preferable, and —C (═O) — is particularly preferable. R ^L has the same meaning as R ^L of formula (2L-2), is a preferred also the same, particularly preferred are hydrogen atom.
A ¹³ is synonymous with the residue obtained by removing the active hydrogen from the (substituted) amino group, hydroxyl group or thiol group bonded to the linking group L ^LD , and specifically has the same meaning as A ¹² and is preferably A. ¹² is the same.
The ring structure in Formula (2L-3) is synonymous with the ring structure in Formula (2L-1), and preferred ones are also the same.

Although the specific example of ligand LD is shown below, this invention is not limited to these by this.
In the present specification, Me in specific examples represents a methyl group, Et represents an ethyl group, t-Bu represents a t-butyl group, and Ph represents a phenyl group.

  First, a specific example of the ligand LD represented by the formula (2L-1) is shown.

  Specific examples of the ligand LD represented by the formula (2L-2) are shown below.

  Specific examples of the ligand LD represented by the formula (2L-3) are shown below.

  These ligands LD are disclosed in, for example, US Patent Application Publication No. 2010/0258175, Japanese Patent No. 4298799, Angew. Chem. Int. Ed. , 2011, 50, 2054-2058 and the methods described in the references cited in these documents, or a method according to these methods.

-Ligand LA-
The ligand LA is a tridentate ligand represented by the following formula (AL-1) or (AL-2). This ligand LA has adsorbing groups Anc ^{1 to} Anc ³ adsorbed on the surface of the semiconductor fine particles.

In the formula, Anc ^{1 to} Anc ³ each independently represent —CO ₂ H, —SO ₃ H, —PO ₃ H _2, or a group in which these protons are dissociated.
Here, the group from which protons are dissociated is, for example, the above-mentioned anion (for example, —CO ₂ ^— , —SO ₃ ^— , —PO ₃ H ^— , —PO ₃ ^{2 —} ) or a salt thereof.
In the present invention, —CO ₂ H or a group in which a proton thereof is dissociated is preferable.

In the formula (AL-1) and the formula (AL-2), R ^AL represents a substituent other than Anc ^{1 to} Anc ³ . R ^AL includes the substituent T described later. R ^AL is an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaromatic ring group, a substituted amino group (especially an alkylsulfonamide group (the carbon number of the alkyl group is Although it does not specifically limit, Preferably it is 1-6.)) Is preferable and an aryl group is more preferable. Here, the heteroaromatic ring group is preferably a thiophene ring group, a furan ring group, or a thiazole ring group, and more preferably a thiophene ring group.
R ^AL may be a group in which a plurality of these groups are bonded, may form a ring by combining at least two groups if R ^AL there are multiple.
b1 represents an integer of 0 to 4, preferably 0 or 1, and more preferably 1.

Specific examples of the ligand LA are shown below, but the present invention is not limited thereto.
In addition, in the following ligand LA, the protons capable of dissociating Anc ^{1 to} Anc ³ are expressed in a state where they are not dissociated, but these protons dissociate, for example, tetrabutylammonium ion ( ⁺ NBu ₄ ), It may be a salt that forms an ion pair with triethylammonium ion ( ⁺ NHEt ₃ ), lithium ion, sodium ion, potassium ion, cesium ion, or the like.

  First, specific examples of the ligand LA represented by the formula (AL-1) are shown.

  Specific examples of the ligand LA represented by the formula (AL-2) are shown below.

  The ligand LA can be synthesized by a metal-halogen exchange reaction, a cross coupling reaction, a Kunafener gel condensation reaction, or the like.

-Ligand LX-
Ligand LX represents a monodentate ligand and is an acyloxy anion, acylthio anion, thioacyloxy anion, thioacylthio anion, acylaminooxy anion, thiocarbamate anion, dithiocarbamate anion, thiocarbonate anion, dithiocarbonate. Nate anion, trithiocarbonate anion, acyl anion, thiocyanate anion, isothiocyanate anion, cyanate anion, isocyanate anion, alkylthioanion, (hetero) arylthioanion, alkoxy anion, (hetero) aryloxyanion, saturated or unsaturated hetero A thioanion or oxyanion bonded to a ring, an amide anion or imide anion bonded to a saturated or unsaturated heterocycle, a silylthioan On, silyloxy anion, anion or coordinated monodentate ligands in these groups is selected from the group consisting of silyl amide anion or a silyl imide anion or a halogen atom, a hydroxide ion (HO ^-), hydrogen sulphide ions (HS ⁻ ), amide ion (NH ₂ ⁻ ), cyano, carbonyl, dialkyl ketone, carbonamide, thiocarbonamide, and thiourea, an anion, atom or compound (including compounds in which a hydrogen atom is substituted for the anion) And monodentate ligands selected from the above. Examples of the atomic group having a lone pair include triarylphosphine (for example, triphenylphosphine) and nitrogen-containing aromatic ring (for example, pyridine).
In addition, when the ligand LX contains an alkyl group, an alkenyl group, an alkynyl group, an alkylene group or the like, these may be linear or branched, and may be substituted or unsubstituted. Moreover, when an aryl group, a heterocyclic group, a cycloalkyl group, etc. are included, they may be substituted or unsubstituted, and may be monocyclic or condensed.

  In the present invention, the ligand LX is preferably a cyanate anion, an isocyanate anion, a thiocyanate anion, an isothiocyanate anion, a selenocyanate anion, an isoselenocyanate anion, more preferably an isocyanate anion, an isothiocyanate anion, an isoselenocyanate anion, An isothiocyanate anion is particularly preferred.

  Specific examples of the ligand LX are shown below, but the present invention is not limited to these. In the following specific examples, Me represents a methyl group, Et represents an ethyl group, and Ph represents a phenyl group.

− Charge neutralization counter ion Y −
Y represents a counter ion when a counter ion is necessary to neutralize the charge. In general, whether a dye is a cation or an anion or has a net ionic charge depends on the metal, ligand and substituent in the metal complex dye.
The metal complex dye may be dissociated and have a negative charge, for example, because the substituent has a dissociable group. In this case, the charge of the entire metal complex dye is electrically neutralized by Y.

  When the counter ion Y is a positive counter ion, for example, the counter ion Y is an inorganic or organic ammonium ion (for example, tetraalkylammonium ion such as tetrabutylammonium ion, triethylbenzylammonium ion, pyridinium ion, etc.), phosphonium ion (For example, tetraalkylphosphonium ions such as tetrabutylphosphonium ions, alkyltriphenylphosphonium ions, triethylphenylphosphonium ions, etc.), alkali metal ions, metal complex ions, or protons. The positive counter ion is preferably an inorganic or organic ammonium ion (such as triethylammonium or tetrabutylammonium ion) or a proton.

  When the counter ion Y is a negative counter ion, for example, the counter ion Y may be an inorganic anion or an organic anion. For example, hydroxide ion, halogen anion (eg, fluoride ion, chloride ion, bromide ion, iodide ion, etc.), substituted or unsubstituted alkylcarboxylate ion (acetate ion, trifluoroacetic acid etc.), substituted Or an unsubstituted aryl carboxylate ion (such as benzoate ion), a substituted or unsubstituted alkyl sulfonate ion (such as methane sulfonate or trifluoromethane sulfonate ion), or a substituted or unsubstituted aryl sulfonate ion (for example, p- Toluene sulfonate ion, p-chlorobenzene sulfonate ion, etc.), aryl disulfonate ion (eg, 1,3-benzene disulfonate ion, 1,5-naphthalenedisulfonate ion, 2,6-naphthalenedisulfonate ion, etc.), alkyl Sulfate ion (eg methyl sulfate) Ion), sulfate ion, thiocyanate ion, perchlorate ion, tetrafluoroborate ion, hexafluorophosphate ion, picrate ion, and the like. Further, as the charge balance counter ion, an ionic polymer or another dye having a charge opposite to that of the dye may be used, and a metal complex ion (for example, bisbenzene-1,2-dithiolatonickel (III)) can also be used. is there. Negative counter ions include halogen anions, substituted or unsubstituted alkyl carboxylate ions, substituted or unsubstituted alkyl sulfonate ions, substituted or unsubstituted aryl sulfonate ions, aryl disulfonate ions, perchlorate ions , Hexafluorophosphate ions are preferred, and halogen anions and hexafluorophosphate ions are more preferred.

− N −
N in the formula (I) represents an integer of 0 to 4, preferably 0 or 1, and more preferably 0.

<Substituent T>
In this specification, about the display of a compound (a complex and a pigment | dye are included), it uses for the meaning containing the salt and its ion besides the said compound itself. In addition, in the present specification, a substituent that does not specify substitution / non-substitution (the same applies to a linking group and a ligand) means that the group may have an arbitrary substituent. This is also synonymous for compounds that do not specify substitution / non-substitution. Preferred substituents include the following substituent T.
Further, in the present specification, when only described as a substituent, it refers to this substituent T, and each group, for example, an alkyl group, is only described. The preferred range and specific examples of the corresponding group of the substituent T are applied.

Examples of the substituent T include the following.
An alkyl group (preferably having 1 to 20 carbon atoms, such as methyl, ethyl, isopropyl, t-butyl, pentyl, heptyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl, trifluoromethyl, etc.), Alkenyl groups (preferably having 2 to 20 carbon atoms, such as vinyl, allyl, oleyl, etc.), alkynyl groups (preferably having 2 to 20 carbon atoms, such as ethynyl, butadiynyl, phenylethynyl, etc.), cycloalkyl groups (preferably Have 3 to 20 carbon atoms, for example, cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc.), cycloalkenyl groups (preferably 5-20 carbon atoms, for example, cyclopentenyl, cyclohexenyl, etc.), aryl groups (preferably Has 6 to 26 carbon atoms, such as phenyl, 1 Naphthyl, 4-methoxyphenyl, 2-chlorophenyl, 3-methylphenyl, etc.), a heterocyclic group (preferably having a carbon number of 2-20 and having at least one oxygen atom, sulfur atom, nitrogen atom) Heterocyclic groups are preferred, for example, 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2-oxazolyl, etc., alkoxy groups (preferably having 1 to 20 carbon atoms, for example, methoxy, Ethoxy, isopropyloxy, benzyloxy and the like), alkenyloxy groups (preferably having 2 to 20 carbon atoms, for example, vinyloxy, allyloxy, etc.), alkynyloxy groups (preferably having 2 to 20 carbon atoms, for example, 2-propenyloxy , 4-butynyloxy, etc.), a cycloalkyloxy group (preferably having 3 carbon atoms) 20, for example, cyclopropyloxy, cyclopentyloxy, cyclohexyloxy, 4-methylcyclohexyloxy and the like, an aryloxy group (preferably having 6 to 26 carbon atoms, such as phenoxy, 1-naphthyloxy, 3-methylphenoxy, 4-methoxyphenoxy and the like), a heterocyclic oxy group (for example, imidazolyloxy, benzoimidazolyloxy, thiazolyloxy, benzothiazolyloxy, triazinyloxy, purinyloxy),

Alkoxycarbonyl group (preferably having 2 to 20 carbon atoms, for example, ethoxycarbonyl, 2-ethylhexyloxycarbonyl, etc.), cycloalkoxycarbonyl group (preferably having 4 to 20 carbon atoms, for example, cyclopropyloxycarbonyl, cyclopentyloxycarbonyl, etc. , Cyclohexyloxycarbonyl, etc.), aryloxycarbonyl groups (preferably having 6 to 20 carbon atoms, such as phenyloxycarbonyl, naphthyloxycarbonyl, etc.), amino groups (preferably having 0 to 20 carbon atoms, alkylamino groups, alkenyls) Including amino group, alkynylamino group, cycloalkylamino group, cycloalkenylamino group, arylamino group, heterocyclic amino group, for example, amino, N, N-dimethylamino, N, N-diethylamino, N-ethyl Amino, N-allylamino, N- (2-propynyl) amino, N-cyclohexylamino, N-cyclohexenylamino, anilino, pyridylamino, imidazolylamino, benzoimidazolylamino, thiazolylamino, benzothiazolylamino, triazinylamino, etc.) A sulfamoyl group (preferably an alkyl, cycloalkyl or aryl sulfamoyl group having 0 to 20 carbon atoms, such as N, N-dimethylsulfamoyl, N-cyclohexylsulfamoyl, N-phenylsulfamoyl, etc. ), An acyl group (preferably having 1 to 20 carbon atoms, such as acetyl, cyclohexylcarbonyl, benzoyl, etc.), an acyloxy group (preferably having 1 to 20 carbon atoms, such as acetyloxy, cyclohexylcarbonyloxy). , Benzoyloxy, etc.), carbamoyl group (preferably a carbamoyl group having 1 to 20 carbon atoms, alkyl, cycloalkyl or aryl, such as N, N-dimethylcarbamoyl, N-cyclohexylcarbamoyl, N-phenylcarbamoyl, etc.) ,

An acylamino group (preferably an acylamino group having 1 to 20 carbon atoms, such as acetylamino, cyclohexylcarbonylamino, benzoylamino, etc.), a sulfonamide group (preferably a sulfoamide having 0 to 20 carbon atoms, alkyl, cycloalkyl or aryl) Group, for example, methanesulfonamide, benzenesulfonamide, N-methylmethanesulfonamide, N-cyclohexylsulfonamide, N-ethylbenzenesulfonamide, etc.), alkylthio group (preferably having 1 to 20 carbon atoms, for example, Methylthio, ethylthio, isopropylthio, benzylthio, etc.), cycloalkylthio groups (preferably having 3 to 20 carbon atoms, such as cyclopropylthio, cyclopentylthio, cyclohexylthio, 4-methylcyclohexyl) Thio), arylthio groups (preferably having 6 to 26 carbon atoms, such as phenylthio, 1-naphthylthio, 3-methylphenylthio, 4-methoxyphenylthio, etc.), alkyl, cycloalkyl or arylsulfonyl groups (preferably carbon In formulas 1 to 20, for example, methylsulfonyl, ethylsulfonyl, cyclohexylsulfonyl, benzenesulfonyl, etc.),

A silyl group (preferably a silyl group having 1 to 20 carbon atoms and substituted with alkyl, aryl, alkoxy and aryloxy, such as triethylsilyl, triphenylsilyl, diethylbenzylsilyl, dimethylphenylsilyl, etc.), silyloxy group ( Preferably, it is a silyloxy group having 1 to 20 carbon atoms and substituted with alkyl, aryl, alkoxy and aryloxy, such as triethylsilyloxy, triphenylsilyloxy, diethylbenzylsilyloxy, dimethylphenylsilyloxy, etc.), hydroxyl group Cyano group, nitro group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), carboxyl group, sulfo group, phosphonyl group, phosphoryl group, boric acid group.

  When the compound or substituent includes an alkyl group, an alkenyl group, etc., these may be linear or branched, and may be substituted or unsubstituted. When an aryl group, a heterocyclic group, or the like is included, they may be monocyclic or condensed, and may be substituted or unsubstituted.

Specific examples of the metal complex dye represented by the above formula (I) are shown below, but the present invention is not limited thereto.
In the following structure, Anc ^{1 to} Anc ³ existing on the ligand LA are expressed in a state where protons capable of dissociation are not dissociated. However, these protons dissociate, for example, tetrabutylammonium ion ( ⁺ NBu ₄ ), triethylammonium ion ( ⁺ NHEt ₃ ), lithium ion, sodium ion, potassium ion, cesium ion and the like may form a salt that forms an ion pair.

  In the metal complex dye of the present invention, the maximum absorption wavelength in the solution is preferably in the range of 300 to 1000 nm, more preferably in the range of 350 to 950 nm, and particularly preferably in the range of 370 to 900 nm.

  The metal complex dye represented by the formula (I) of the present invention is a method according to each method described in Patent Documents 1 and 2 and Non-Patent Document 1 described above, and a synthesis method in Examples described later. It can be synthesized by a similar method.

<< Photoelectric conversion element and dye-sensitized solar cell >>
For example, as shown in FIG. 1, the photoelectric conversion element 10 of the present invention has a photoelectric conversion element 10 including a conductive support 1, a photoreceptor layer 2 including semiconductor fine particles sensitized by a dye (metal complex dye) 21, It consists of a charge transfer layer 3 and a counter electrode 4 which are hole transport layers. Here, in the present invention, it is preferable that the co-adsorbent is adsorbed on the semiconductor fine particles 22 together with the dye (metal complex dye) 21. The conductive support 1 provided with the photoreceptor layer 2 functions as a working electrode in the photoelectric conversion element 10. In the present embodiment, the photoelectric conversion element 10 is shown as a system 100 using a dye-sensitized solar cell that can be used for a battery for causing the operating means M to work with the external circuit 6.

  In the present embodiment, the light-receiving electrode 5 includes a conductive support 1 and a photoreceptor layer 2 including semiconductor fine particles adsorbed with a dye (metal complex dye) 21. The photoreceptor layer 2 is designed according to the purpose, and may be a single layer structure or a multilayer structure. The dye (metal complex dye) 21 in one photosensitive layer may be one kind or a mixture of various kinds, but at least one of them uses the metal complex dye of the present invention described above. The light incident on the photoreceptor layer 2 excites the dye (metal complex dye) 21. The excited dye has high energy electrons, and the electrons are transferred from the dye (metal complex dye) 21 to the conduction band of the semiconductor fine particles 22 and reach the conductive support 1 by diffusion. At this time, the dye (metal complex dye) 21 is an oxidant, but the electrons on the electrode work in the external circuit 6 and pass through the counter electrode 4 so that the oxidant of the dye (metal complex dye) 21 and By returning to the photoreceptor layer 2 where the electrolyte is present, it functions as a solar cell.

  In the present invention, the material used for the photoelectric conversion element or the dye-sensitized solar cell and the method for producing each member may be the usual ones of this type, for example, US Pat. No. 4,927,721. U.S. Pat.No. 4,684,537, U.S. Pat.No. 5,0843,65, U.S. Pat.No. 5,350,644, U.S. Pat.No. 5,463,057, Reference can be made to US Pat. No. 5,525,440, JP-A-7-249790, JP-A-2004-220974, and JP-A-2008-135197.

  Hereinafter, an outline of the main members will be described.

− Conductive support −
The conductive support is preferably a support made of glass or plastic having a conductive film layer on the surface, such as a metal, which is conductive in itself. As the support, in addition to glass and plastic, ceramic (Japanese Patent Laid-Open No. 2005-135902) or conductive resin (Japanese Patent Laid-Open No. 2001-160425) may be used. On the support, the surface may be provided with a light management function. For example, an antireflection film in which high refractive films and low refractive index oxide films described in JP-A-2003-123859 are alternately laminated, A light guide function described in JP-A-2002-260746 is exemplified.

  The thickness of the conductive film layer is preferably 0.01 to 30 μm, more preferably 0.03 to 25 μm, and particularly preferably 0.05 to 20 μm.

It is preferable that the conductive support is substantially transparent. Substantially transparent means that the light transmittance is 10% or more, preferably 50% or more, particularly preferably 80% or more. As the transparent conductive support, a glass or plastic coated with a conductive metal oxide is preferable. As the metal oxide, tin oxide is preferable, and indium-tin oxide and fluorine-doped oxide are particularly preferable. The coating amount of the conductive metal oxide at this time is preferably 0.1 to 100 g per 1 m ² of glass or plastic support. When a transparent conductive support is used, light is preferably incident from the support side.

− Semiconductor fine particles −
The semiconductor fine particles are preferably metal chalcogenide (for example, oxide, sulfide, selenide, etc.) or perovskite fine particles. Preferred examples of the metal chalcogenide include titanium, tin, zinc, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, tantalum oxide, cadmium sulfide, cadmium selenide, and the like. . Preferred perovskites include strontium titanate and calcium titanate. Of these, titanium oxide (titania), zinc oxide, tin oxide, and tungsten oxide are particularly preferable.

  The crystal structure of titania includes anatase type, brookite type, or rutile type, and anatase type and brookite type are preferable. Titania nanotubes, nanowires, and nanorods may be mixed with titania fine particles or used as a semiconductor electrode.

  The particle diameters of the semiconductor fine particles are 0.001 to 1 μm as primary particles and 0.01 to 100 μm as the average particle diameter of the dispersion in terms of the average particle diameter when the projected area is converted into a circle. preferable. Examples of the method for coating the semiconductor fine particles on the conductive support include a wet method, a dry method, and other methods.

  It is preferable to form a short-circuit prevention layer between the transparent conductive film and the semiconductor layer (photoreceptor layer) in order to prevent reverse current due to direct contact between the electrolyte and the electrode. In order to prevent contact between the photoelectrode and the counter electrode, it is preferable to use a spacer or a separator. The semiconductor fine particles preferably have a large surface area so that many dyes can be adsorbed. For example, in a state where the semiconductor fine particles are coated on the support, the surface area is preferably 10 times or more, more preferably 100 times or more the projected area. Although there is no restriction | limiting in particular in this upper limit, Usually, it is about 5000 times. In general, the greater the thickness of the layer containing semiconductor fine particles, the greater the amount of dye that can be carried per unit area and the higher the light absorption efficiency, but the longer the diffusion distance of the generated electrons, the greater the loss due to charge recombination. . Although the preferable thickness of the photoreceptor layer which is a semiconductor layer changes with uses of an element, it is 0.1-100 micrometers typically. When using as a dye-sensitized solar cell, it is preferable that it is 1-50 micrometers, and it is more preferable that it is 3-30 micrometers. The semiconductor fine particles may be fired at a temperature of 100 to 800 ° C. for 10 minutes to 10 hours in order to adhere the particles to each other after being applied to the support. When glass is used as the support, the film forming temperature is preferably 400 to 60 ° C.

The coating amount of the semiconductor fine particles per 1 m ² of the support is preferably 0.5 to 500 g, more preferably 5 to 100 g. The total amount of the dye used is preferably 0.01 to 100 mmol, more preferably 0.1 to 50 mmol, particularly preferably 0.1 to 10 mmol, per 1 m ² of the support. In this case, the amount of the metal complex dye of the present invention is preferably 5 mol% or more. Further, the adsorption amount of the dye to the semiconductor fine particles is preferably 0.001 to 1 mmol, more preferably 0.1 to 0.5 mmol, with respect to 1 g of the semiconductor fine particles. By using such a dye amount, the sensitizing effect in the semiconductor fine particles can be sufficiently obtained.
When the dye is a salt, the counter ion of the specific metal complex dye is not particularly limited, and examples thereof include alkali metal ions and quaternary ammonium ions.

  Thus, the semiconductor fine particles are adsorbed with the added metal complex dye represented by the above formula (I). A method of adsorption will be described later. After adsorbing the dye, the surface of the semiconductor fine particles may be treated with amines. Preferable amines include pyridines (for example, 4-tert-butylpyridine, polyvinylpyridine) and the like. These may be used as they are in the case of a liquid, or may be used by dissolving in an organic solvent.

  In the photoelectric conversion element (for example, photoelectric conversion element 10) and the dye-sensitized solar cell (for example, photoelectrochemical cell 20) of the present invention, at least the metal complex dye of the present invention is used.

In the present invention, the metal complex dye of the present invention may be used in combination with another dye.
Examples of the dye used in combination include Japanese Patent No. 3731852, Japanese Patent Publication No. 2002-512729, Japanese Patent Application Laid-Open No. 2001-59062, Japanese Patent Application Laid-Open No. 2001-6760, Japanese Patent No. 3430254, Japanese Patent Application Laid-Open No. 2003-212851, and International Publication No. 2007/91525. No. pamphlet, JP-A-2001-291534, JP-A-2012-012570, Ru complex dye disclosed in JP-A-11-214730, JP-A-2012-144688, JP-A-2012-84503 The squarylium cyanine dyes described in the above publications, such as JP 2004-063274, JP 2005-123033, JP 2007-287694, JP 2008-71648, JP 2007-287694, and International Publication No. 2007. / 119525 pamphlet Organic dyes described in broadcast or specification, Angew. Chem. Int. Ed. , 49, 1-5 (2010), etc., Angew. Chem. Int. Ed. , 46, 8358 (2007), and the like. The dye used in combination is preferably a Ru complex dye, a squarylium cyanine dye, or an organic dye.

  When the metal complex dye of the present invention is used in combination with another dye, the ratio of the mass of the metal complex dye of the present invention / the mass of the other dye is preferably 95/5 to 10/90, and 95/5 to 50/50. Is more preferable, 95/5 to 60/40 is more preferable, 95/5 to 65/35 is particularly preferable, and 95/5 to 70/30 is most preferable.

− Charge transfer layer −
The charge transfer layer used in the photoelectric conversion element of the present invention is a layer having a function of replenishing electrons to the dye oxidant, and is provided between the light receiving electrode and the counter electrode (counter electrode). Typical examples include a liquid electrolyte in which a redox couple is dissolved in an organic solvent, a so-called gel electrolyte in which a polymer matrix is impregnated with a liquid in which the redox couple is dissolved in an organic solvent, and a molten salt containing the redox couple. It is done. A liquid electrolyte is preferred for increasing efficiency. Nitrile compounds, ether compounds, ester compounds and the like are used as the organic solvent for the liquid electrolyte, but nitrile compounds are preferred, and acetonitrile and methoxypropionitrile are particularly preferred.

  As an oxidation-reduction pair, for example, iodine and iodide (iodide salt, ionic liquid is preferable, lithium iodide, tetrabutylammonium iodide, tetrapropylammonium iodide, methylpropylimidazolium iodide are preferable) Combinations, combinations of alkyl viologens (for example, methyl viologen chloride, hexyl viologen bromide, benzyl viologen tetrafluoroborate) and reduced forms thereof, combinations of polyhydroxybenzenes (for example, hydroquinone, naphthohydroquinone, etc.) and oxidized forms thereof, divalent And combinations of trivalent iron complexes (for example, combinations of red blood salts and yellow blood salts), combinations of divalent and trivalent cobalt complexes, and the like. Of these, a combination of iodine and iodide, and a combination of divalent and trivalent cobalt complexes are preferred.

  In particular, the cobalt complex is preferably a complex represented by the following formula (CC).

    Co (LL) ma (X) mb · CI Formula (CC)

  In the formula (CC), LL represents a bidentate or tridentate ligand. X represents a monodentate ligand. ma represents an integer of 0 to 3. mb represents the integer of 0-6. CI represents a counter ion when a counter ion is required to neutralize the charge.

CI includes Y in the formula (I).
LL is preferably a ligand represented by the following formula (LC).

In the formula (LC), Z ^LC1 , Z ^LC2 and Z ^LC3 each independently represent a nonmetallic atom group necessary for forming a 5- or 6-membered ring. Z ^LC1 , Z ^LC2 and Z ^LC3 may have a substituent and may be closed with an adjacent ring via the substituent. X ^LC1 and X ^LC3 represent a carbon atom or a nitrogen atom. q represents 0 or 1; Examples of the substituent include the above-described substituent T.

  X is preferably a halogen ion.

  The ligand represented by the formula (LC) is more preferably a ligand represented by the following formulas (LC-1) to (LC-3).

R ^{LC1 to} R ^LC9 represent a substituent. q1, q2, q6 and q7 each independently represents an integer of 0 to 4. q3 and q5 each independently represents an integer of 0 to 3. q4 represents an integer of 0 to 2.

In formulas (LC-1) to (LC-3), examples of the substituent for R ^{LC1 to} R ^LC9 include an aliphatic group, an aromatic group, and a heterocyclic group. Specific examples of the substituent include alkyl groups, alkoxy groups, alkylthio groups, aryl groups, aryloxy groups, arylthio groups, and heterocyclic rings. Preferred examples include alkyl groups (eg methyl, ethyl, n-butyl, n-hexyl, isobutyl, sec-butyl, t-butyl, n-dodecyl, cyclohexyl, benzyl etc.), aryl groups (eg phenyl, tolyl, naphthyl). Etc.), alkoxy groups (eg methoxy, ethoxy, isopropoxy, butoxy etc.), alkylthio groups (eg methylthio, n-butylthio, n-hexylthio, 2-ethylhexylthio etc.), aryloxy groups (eg phenoxy, naphthoxy etc.) Etc.), arylthio groups (eg, phenylthio, naphthylthio, etc.), and heterocyclic groups (eg, 2-thienyl, 2-furyl, etc.).

  Specific examples of the cobalt complex represented by the formula (LC) include the following complexes.

  When a combination of iodine and iodide is used as the electrolyte, it is preferable to further use an iodine salt of a 5-membered or 6-membered nitrogen-containing aromatic cation.

  As the organic solvent for dissolving the redox couple, these are aprotic polar solvents (for example, acetonitrile, propylene carbonate, ethylene carbonate, dimethylformamide, dimethyl sulfoxide, sulfolane, 1,3-dimethylimidazolinone, 3-methyloxazolidinone, etc. ) Is preferred. Examples of the polymer used for the matrix of the gel electrolyte include polyacrylonitrile and polyvinylidene fluoride. Examples of the molten salt include those imparted with fluidity at room temperature by mixing polyethylene oxide with lithium iodide and at least one other lithium salt (such as lithium acetate and lithium perchlorate). It is done. In this case, the amount of the polymer added is 1 to 50% by mass. Moreover, (gamma) -butyrolactone may be contained in electrolyte solution, and thereby the diffusion efficiency of iodide ion becomes high and conversion efficiency improves.

  As an additive to the electrolyte, in addition to the aforementioned 4-tert-butylpyridine, an aminopyridine compound, a benzimidazole compound, an aminotriazole compound and an aminothiazole compound, an imidazole compound, an aminotriazine compound, a urea derivative, Amide compounds, pyrimidine compounds and nitrogen-free heterocycles can be added.

  In order to improve efficiency, a method of controlling the water content of the electrolytic solution may be taken. Preferred methods for controlling moisture include a method for controlling the concentration and a method in which a dehydrating agent is allowed to coexist. In order to reduce the toxicity of iodine, an inclusion compound of iodine and cyclodextrin may be used, and conversely, a method of constantly supplying water may be used. Cyclic amidine may be used, and an antioxidant, hydrolysis inhibitor, decomposition inhibitor, and zinc iodide may be added.

  Molten salts may be used as the electrolyte, and preferred molten salts include ionic liquids containing imidazolium or triazolium type cations, oxazolium-based, pyridinium-based, guanidinium-based, and combinations thereof. These cationic systems may be combined with specific anions. Additives may be added to these molten salts. You may have a liquid crystalline substituent. Further, a quaternary ammonium salt-based molten salt may be used.

  As molten salts other than these, for example, flowability at room temperature was imparted by mixing polyethylene oxide with lithium iodide and at least one other lithium salt (for example, lithium acetate, lithium perchlorate, etc.). And the like.

  The electrolyte may be quasi-solidified by adding a gelling agent to an electrolyte solution composed of an electrolyte and a solvent to cause gelation. Examples of the gelling agent include organic compounds having a molecular weight of 1000 or less, Si-containing compounds having a molecular weight in the range of 500 to 5000, organic salts made of a specific acidic compound and a basic compound, sorbitol derivatives, and polyvinylpyridine.

Alternatively, a method of confining the matrix polymer, the crosslinkable polymer compound or monomer, the crosslinking agent, the electrolyte, and the solvent in the polymer may be used.
As a matrix polymer, a polymer having a nitrogen-containing heterocyclic ring in the main chain or side chain repeating unit, a crosslinked product obtained by reacting these with an electrophilic compound, a polymer having a triazine structure, or having a ureido structure Polymers, liquid crystalline compounds, ether-bonded polymers, polyvinylidene fluoride, methacrylate / acrylate, thermosetting resins, cross-linked polysiloxane, polyvinyl alcohol (PVA), polyalkylene glycol and dextrin, etc. Examples include inclusion compounds, systems to which oxygen-containing or sulfur-containing polymers are added, and natural polymers. An alkali swelling polymer, a polymer having a compound capable of forming a charge transfer complex between a cation moiety and iodine in one polymer may be added to these.

  As the matrix polymer, a system including a cross-linked polymer obtained by reacting a functional group such as a hydroxyl group, an amino group, or a carboxyl group with one or more functional isocyanate as one component may be used. In addition, a crosslinking method in which a crosslinked polymer composed of a hydrosilyl group and a double bond compound, polysulfonic acid, polycarboxylic acid, or the like is reacted with a divalent or higher valent metal ion compound may be used.

  Examples of the solvent that can be preferably used in combination with the quasi-solid electrolyte include a specific phosphate ester, a mixed solvent containing ethylene carbonate, and a solvent having a specific dielectric constant. The liquid electrolyte solution may be held in a solid electrolyte membrane or pores, and preferred methods thereof include conductive polymer membranes, fibrous solids, and cloth solids such as filters.

  Instead of the above liquid electrolyte and quasi-solid electrolyte, a solid charge transport layer such as a p-type semiconductor or a hole transport material, for example, CuI, CuNCS, or the like can be used. Also, Nature, vol. 486, p. The electrolyte described in 487, 2012, or the like may be used. An organic hole transport material may be used as the solid charge transport layer. The hole transport layer is preferably a conductive polymer such as polythiophene, polyaniline, polypyrrole, and polysilane, and a spiro compound in which two rings share a tetrahedral structure such as C or Si, or an aromatic such as triarylamine. Examples include amine derivatives, triphenylene derivatives, nitrogen-containing heterocyclic derivatives, and liquid crystalline cyano derivatives.

  The redox couple becomes an electron carrier. The total concentration is preferably 0.01 mol / 1 or more, more preferably 0.1 mol / 1, and particularly preferably 0.3 mol / 1 or more. The upper limit in this case is not particularly limited, but is usually about 5 mol / 1.

− Coadsorbent −
In the photoelectric conversion element of this invention, it is preferable to use a coadsorbent with the metal complex dye of this invention or the pigment | dye used together if necessary. As such a co-adsorbent, a co-adsorbent having at least one acidic group (preferably a carboxyl group or a salt group thereof) is preferable, and examples thereof include a compound having a fatty acid or a steroid skeleton. The fatty acid may be a saturated fatty acid or an unsaturated fatty acid, and examples thereof include butanoic acid, hexanoic acid, octanoic acid, decanoic acid, hexadecanoic acid, dodecanoic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid.
Examples of the compound having a steroid skeleton include cholic acid, glycocholic acid, chenodeoxycholic acid, hyocholic acid, deoxycholic acid, lithocholic acid, ursodeoxycholic acid and the like. Preferred are cholic acid, deoxycholic acid and chenodeoxycholic acid, and more preferred are chenodeoxycholic acid.

  A preferred co-adsorbent is a compound represented by the following formula (CA).

In the formula, R ^A1 represents a substituent having an acidic group. R ^A2 represents a substituent. nA represents an integer of 0 or more.
An acidic group is synonymous with what was shown previously.
nA is preferably 2 to 4.

  Examples of these specific compounds include the compounds exemplified as the compounds having the above-mentioned steroid skeleton.

  The co-adsorbent of the present invention has an effect of suppressing inefficient association of dyes by adsorbing to semiconductor fine particles and an effect of preventing reverse electron transfer from the surface of the semiconductor fine particles to the redox system in the electrolyte. The amount of coadsorbent used is not particularly limited, but it is preferably 1 to 200 mol, more preferably 10 to 150 mol, and particularly preferably 20 to 50 mol with respect to 1 mol of the dye. It is preferable from the viewpoint of being effectively expressed.

The counter electrode (also referred to as a counter electrode) preferably serves as a positive electrode for a dye-sensitized solar cell (photoelectrochemical cell). The counter electrode is usually synonymous with the conductive support described above, but the support is not necessarily required in a configuration in which the strength is sufficiently maintained. As the structure of the counter electrode, a structure having a high current collecting effect is preferable. In order for light to reach the photosensitive layer, at least one of the conductive support and the counter electrode must be substantially transparent. In the dye-sensitized solar cell of the present invention, the conductive support is preferably transparent, and sunlight is preferably incident from the support side. In this case, it is more preferable that the counter electrode has a property of reflecting light. As the counter electrode of the dye-sensitized solar cell, glass or plastic on which metal or conductive oxide is vapor-deposited is preferable, and glass on which platinum is vapor-deposited is particularly preferable. In the dye-sensitized solar cell, it is preferable to seal the side surface of the battery with a polymer, an adhesive or the like in order to prevent the constituents from evaporating. The characteristics of the dye-sensitized solar cell of the present invention thus obtained are preferably an open circuit voltage of 0.01 to 1.5 V and a short-circuit current density of 0.001 to 20 mA / cm when AM 1.5G is 100 mW / cm ^2. cm ² , form factor 0.1-0.9, conversion efficiency 0.001-25%.

  The present invention is disclosed in Japanese Patent No. 4260494, Japanese Patent Application Laid-Open No. 2004-146425, Japanese Patent Application Laid-Open No. 2000-340269, Japanese Patent Application Laid-Open No. 2002-289274, Japanese Patent Application Laid-Open No. 2004-152613, and Japanese Patent Application Laid-Open No. 9-27352. It can apply to the described photoelectric conversion element and a dye-sensitized solar cell. JP-A-2004-152613, JP-A-2000-90989, JP-A-2003-217688, JP-A-2002-367686, JP-A-2003-323818, JP-A-2001-43907, JP 2000-340269, JP 2005-85500, JP 2004-273272, JP 2000-323190, JP 2000-228234, JP 2001-266963, JP 2001-185244, JP-T-2001-525108, JP-A-2001-203377, JP-A-2000-1000048, JP-A-2001-210390, JP-A-2002-280588, JP-A-2001-2001. 273937, JP-A 2000-2859 7 No. photoelectric conversion device described in JP 2001-320068 Patent Publication can be applied to a dye-sensitized solar cell.

<< Dye solution, semiconductor electrode using the same, and method for producing dye-sensitized solar cell >>
In the present invention, it is preferable to produce a semiconductor electrode (also referred to as a dye adsorption electrode) by using a dye solution containing the metal complex dye of the present invention.
In such a dye solution, the metal complex dye of the present invention is dissolved in a solvent and may contain a co-adsorbent and other components as necessary.
Examples of the solvent to be used include, but are not limited to, the solvents described in JP-A No. 2001-291534. In the present invention, an organic solvent is preferable, and alcohols, amides, nitriles, hydrocarbons, and a mixed solvent of two or more of these are preferable. The mixed solvent is preferably a mixed solvent of an alcohol and a solvent selected from amides, nitriles or hydrocarbons. Further preferred are alcohols and amides, mixed solvents of alcohols and hydrocarbons, and particularly preferred are mixed solvents of alcohols and amides. Specifically, methanol, ethanol, propanol, butanol, dimethylformamide, and dimethylacetamide are preferable.

The dye solution preferably contains a co-adsorbent. As the co-adsorbent, the above-mentioned co-adsorbent is preferable, and among them, the compound represented by the formula (CA) is preferable.
Here, the dye solution of the present invention is preferably one in which the concentration of the metal complex dye or coadsorbent is adjusted so that the solution can be used as it is when a photoelectric conversion element or a dye-sensitized solar cell is prepared. . In this invention, it is preferable to contain the metal complex pigment | dye of this invention 0.001-0.1 mass%.

It is particularly preferable to adjust the water content of the dye solution. Therefore, in the present invention, it is preferable to adjust the content (content) of water to 0 to 0.1% by mass.
Similarly, adjustment of the water content of the electrolytic solution in the photoelectric conversion element or the dye-sensitized solar cell is also preferable for effectively achieving the effects of the present invention. For this reason, the water content (content rate) of the electrolytic solution is preferable. Is preferably adjusted to 0 to 0.1% by mass. The electrolytic solution is particularly preferably adjusted with a dye solution.
In the present invention, a semiconductor electrode for a dye-sensitized solar cell in which a metal complex dye is supported on the surface of semiconductor fine particles provided in the semiconductor electrode using the dye solution is preferable.
Moreover, it is preferable to manufacture a dye-sensitized solar cell by making a metal complex dye carry | support on the semiconductor fine particle surface with which a semiconductor electrode is equipped using the said dye solution.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention should not be construed as being limited thereto.

Example 1 [Synthesis of Metal Complex Dye]
In the following manner, the following metal complex dyes Dye-1-5, 12, 24, 26, 29, 31, 34, 36 and 41, Dye-2-2, and Dye-3-2, 3 and 6 Synthesized.

1. Synthesis of Dye-1-5 First, the bidentate ligand LD-1-9 of the metal complex dye Dye-1-5 was synthesized according to the following scheme.

  25 g of compound LD-1-9a (2-acetyl-5-bromopyrimidine) synthesized by the method described in International Publication No. 2012/126672 is dissolved in 1000 mL of THF (tetrahydrofuran) under a nitrogen atmosphere, and 200 mL of water, 63 g of 5-hexylthiophene-2-boronic acid pinacol ester, 86 g of potassium carbonate, and 7 g of tetrakis (triphenylphosphine) palladium were introduced and heated to reflux for 7 hours. After returning to room temperature, 1N dilute hydrochloric acid (1000 mL) and ethyl acetate (1000 mL) were introduced, and the phases were separated, and the organic layer was concentrated. The obtained crude product was recrystallized from acetonitrile to obtain 25 g of compound LD-1-9b.

  Under a nitrogen atmosphere, 25 g of LD-1-9b was dissolved in 500 mL of THF (tetrahydrofuran), and while stirring at 0 ° C., 12 g of sodium ethoxide was added and stirred for 15 minutes. Thereafter, 37 g of ethyl trifluoroacetate was added dropwise and stirred at 70 ° C. for 20 hours. After returning to room temperature, an aqueous ammonium chloride solution was dropped and separated, and the organic layer was concentrated to obtain 34 g of a crude product LD-1-9c. This was dissolved in 600 mL of ethanol under a nitrogen atmosphere, 9 g of hydrazine monohydrate was added while stirring at room temperature, and the mixture was heated at an external temperature of 90 ° C. for 12 hours. Thereafter, 20 mL of concentrated hydrochloric acid was added and stirred for 1 hour. After concentration, the organic layer was concentrated after extraction and liquid separation with 150 mL of sodium bicarbonate water and 150 mL of ethyl acetate. After recrystallization from acetonitrile, 24 g of compound LD-1-9 was obtained.

  Subsequently, metal complex dye Dye-1-5 was synthesized according to the following scheme using the obtained ligand LD-1-9.

In a nitrogen atmosphere, 6.1 g of a trichlororuthenium complex [RuCl3 (LA-1-1a)] coordinated with a trimethyl ester (LA-1-1a) of the ligand LA-1-1 was coordinated to a 50 mL flask. After introducing 3.8 g of the child LD-1-9 and adding 200 mL of a mixed solvent of ethanol / water (volume ratio = 5: 1) as a solvent, 3.1 g of N-methylmorpholine was added and refluxed for 2 hours. . After cooling to room temperature, 7.6 g of ammonium thiocyanate was added, and the mixture was heated to reflux again for 5 hours. After cooling to room temperature, the precipitated black solid was collected by filtration. The black solid was purified by silica gel column chromatography to obtain 4.6 g of Dye-1-5b.
1.5 g of this Dye-1-5b was dissolved in 30 mL of a tetrahydrofuran / methanol mixed solvent (volume ratio = 1: 1) under a nitrogen atmosphere, and 10 mL of a 3N aqueous sodium hydroxide solution was added dropwise with stirring at room temperature. did. The mixture was stirred as it was at room temperature for 1 hour, and a methanol solution of 1N trifluoromethanesulfonic acid was slowly added dropwise thereto until the pH reached 3.0. The gradually precipitated crystals were collected by filtration, washed with methanol, and dried to obtain 1.3 g of the target metal complex dye Dye-1-5.

2. Synthesis of Dye-1-12 First, the bidentate ligand LD-1-25 of the metal complex dye Dye-1-12 was synthesized according to the following scheme.

LD-1-25c was synthesized by using LD-1-25a instead of LD-1-9b in the same reaction as converting LD-1-9b to LD-1-9. . This LD-1-25a is disclosed in Acta Chem. Scand. , 43, 62 (1989).
Subsequently, while stirring 22.2 g of diisopropylamine and 104 mL of tetrahydrofuran at −40 ° C. under a nitrogen atmosphere, 125 mL of 1.6M n-butyllithium hexane solution was dropped, and then stirred for 30 minutes. Thereafter, 324 mL of diisopropylamine was added dropwise, and 21.6 g of LD-1-25c was slowly introduced. After stirring at 0 ° C. for 30 minutes, 78 mL of tetrahydrofuran in which 20.5 g of 5-hexylthiophene-2-carboxaldehyde was dissolved was added dropwise and stirred at room temperature for 30 minutes. An ammonium chloride solution was added, and the organic layer obtained by extraction and separation with ethyl acetate was concentrated to obtain a crude product of LD-1-25d. Under a nitrogen atmosphere, 100 mL of toluene was added to the crude product, and 14.9 g of PPTS (pyridinium paratoluenesulfonic acid) was added while stirring at room temperature, and the mixture was heated to reflux for 6.5 hours. After concentration, liquid separation was performed with saturated aqueous sodium hydrogen carbonate and ethyl acetate, and the organic layer was concentrated. The obtained crystals were purified by recrystallization from methanol and isopropyl alcohol to obtain 19.5 g of LD-1-25.

  Subsequently, using the obtained ligand LD-1-25, a metal complex dye Dye-1-12 was synthesized in the same manner as the metal complex dye Dye-1-5.

3. Synthesis of Dye-1-24 First, the bidentate ligand LD-2-16 of the metal complex dye Dye-1-24 was synthesized according to the following scheme.

LD-2-16b is similar to the reaction for synthesizing LD-1-9b from LD-1-9a described above from LD-2-16a and N- (tert-butoxycarbonyl) indole-2-boronic acid. The coupling product obtained by synthesis by the reaction was obtained by dissolving in an appropriate amount of dichloromethane and adding an excess amount of trifluoroacetic acid to perform Boc deprotection. Using this LD-2-16b, LD-2-16 was synthesized by performing the same reaction as the above-described reaction for synthesizing LD-1-25 from LD-1-25c.
Subsequently, using the obtained ligand LD-2-16, a metal complex dye Dye-1-24 was synthesized in the same manner as the metal complex dye Dye-1-5.

4). Synthesis of Dye-1-26 First, the bidentate ligand LD-3-1 of the metal complex dye Dye-1-26 was synthesized according to the following scheme.

By using LD-3-1a in place of LD-1-9b, the same reaction as the above-mentioned reaction for converting LD-1-9b to LD-1-9 is used. Was synthesized.
Subsequently, using the obtained ligand LD-3-1, a metal complex dye Dye-1-26 was synthesized in the same manner as the metal complex dye Dye-1-5.

5. Synthesis of Dye-1-29 The bidentate ligand LD-6-1 of the metal complex dye Dye-1-29 was obtained from Bioorg. Med. Chem. It was synthesized according to the method described in Lett, 12, 471 (2002). Using the obtained ligand LD-6-1, a metal complex dye Dye-1-29 was synthesized in the same manner as the metal complex dye Dye-1-5.

6). Synthesis of Dye-1-31 First, bidentate ligand LD-6-13 of metal complex dye Dye-1-31 was synthesized according to the following scheme.

LD-6-13c was synthesized from LD-2-16a by the same method as the synthesis method of LD-2-16. 20 g of the obtained LD-6-13c was dissolved in 200 mL of hexamethylphosphoric triamide (HMPA) under a nitrogen atmosphere, 3.5 g of sodium methanethiolate was introduced, and the mixture was stirred at 140 ° C. for 12 hours. After cooling to room temperature, 200 mL of 1N dilute hydrochloric acid and 200 mL of ethyl acetate were introduced, the organic layer was recovered by liquid separation, and the crude product obtained by concentration was purified by silica gel column chromatography to obtain LD-6. 16g of -13 was obtained.
Subsequently, using the obtained ligand LD-6-13, a metal complex dye Dye-1-31 was synthesized in the same manner as the metal complex dye Dye-1-5.

7). Synthesis of Dye-1-34 The bidentate ligand LD-8-1 of the metal complex dye Dye-1-34 was obtained from Bioorg. Med. Chem. Synthesized according to the method described in Lett, 12, 471 (2002). Using the obtained ligand LD-8-1, a metal complex dye Dye-1-34 was synthesized in the same manner as the metal complex dye Dye-1-5.

8). Synthesis of Dye-1-36 The bidentate ligand LD-9-1 of the metal complex dye Dye-1-36 was obtained from Dalton Trans. , 40, 5476 (2011). Using the obtained ligand LD-9-1, a metal complex dye Dye-1-36 was synthesized in the same manner as the metal complex dye Dye-1-5.

9. Synthesis of Dye-1-41 First, bidentate ligand LD-9-16 of metal complex dye Dye-1-41 was synthesized according to the following scheme.

LD-9-16a was synthesized according to the method described in Japanese Patent No. 4338192, and this was synthesized by the same reaction as that for synthesizing LD-1-25 from the above-mentioned LD-1-25c. Converted to 16b.
Under a nitrogen atmosphere, 15.4 g of LD-9-16b was dissolved in 300 mL of DMSO (dimethyl sulfoxide), 2.5 g of sodium cyanide was added, and the mixture was stirred at 120 ° C. for 2 hours. After cooling to room temperature, 1500 mL of water was added and the precipitated solid was collected by filtration and washed with water to obtain a crude product of LD-9-16c. This was dissolved in 300 mL of ethanol, 15 mL of 1N aqueous potassium hydroxide solution was added, and the mixture was heated to reflux for 13 hours. After cooling to room temperature, 500 mL of water and 500 mL of ethyl acetate were added, liquid separation was performed, and the crude product obtained by concentrating the organic layer was purified by silica gel column chromatography to obtain 7.6 g of LD-9-16. Obtained.
Subsequently, using the obtained ligand LD-9-16, a metal complex dye Dye-1-41 was synthesized in the same manner as the metal complex dye Dye-1-5.

10. Synthesis of Dye-2-2 First, Dye-2-2a was synthesized according to the following scheme as a precursor of the metal complex dye Dye-2-2.

As a raw material, LA-2-6a was prepared according to J. Am. Chem. Soc. , 130, 11013 (2008). In addition, LA-2-6b is described in J. Org. Am. Chem. Soc. , 134, 7488 (2012).
Under a nitrogen atmosphere, 3.4 g of LA-2-6a was dissolved in 40 mL of meta-xylene, 4.4 g of LA-2-6b and 1.2 g of tetrakis (triphenylphosphine) palladium were introduced, and the mixture was stirred at 120 ° C. for 20 hours. . After cooling to room temperature, 50 mL of a 2N aqueous sodium hydroxide solution and 40 mL of toluene were introduced and separated, and then the crude product obtained by concentrating the organic layer was purified by silica gel column chromatography. 2.6g of 2-6c was obtained.
Subsequently, 2.6 g of LA-2-6c was dissolved in 100 mL of THF (tetrahydrofuran) under a nitrogen atmosphere, and 20 mL of water, 1.6 g of 2,4,6-trimethylbenzeneboronic acid, 8.6 g of potassium carbonate, tetrakis ( 0.7 g of triphenylphosphine) palladium was introduced, and the mixture was heated to reflux for 10 hours. After returning to room temperature, 1N diluted hydrochloric acid (100 mL) and ethyl acetate (100 mL) were introduced, and the mixture was separated, and the organic layer was concentrated. The obtained crude product was purified by silica gel column chromatography to obtain 2.5 g of LA-2-6d.
Furthermore, 1 g of ethanol and 1.3 g of ruthenium (III) chloride hydrate were introduced into 2.5 g of LA-2-6d under a nitrogen atmosphere, and the mixture was heated to reflux for 10 hours. After cooling to room temperature, the purified crystals were collected by filtration and washed with ethanol to obtain 3.5 g of Dye-2-2a.
Using the precursor Dye-2-2a synthesized as described above, a metal complex dye Dye-2-2 was synthesized in the same manner as the metal complex dye Dye-1-5.

11. Synthesis of Dye-3-2 The metal complex dye Dye-3-2 was synthesized according to the following scheme.

In a nitrogen atmosphere, 6.1 g of a trichlororuthenium complex [RuCl3 (LA-1-1a)] coordinated with a trimethyl ester (LA-1-1a) of the ligand LA-1-1 was coordinated to a 50 mL flask. After introducing 4.1 g of a child LD-1-25 and adding 200 mL of a mixed solvent of ethanol / water (volume ratio = 5: 1) as a solvent, 3.1 g of N-methylmorpholine was added and refluxed for 2 hours. . After cooling to room temperature, the precipitated black solid was collected by filtration. The black solid was purified by alumina column chromatography to obtain 3.7 g of Dye-3-2a.
1.7 g of this Dye-3-2a was dissolved in 30 mL of a tetrahydrofuran / methanol mixed solvent (volume ratio = 1: 1) under a nitrogen atmosphere, and 10 mL of a 3N aqueous sodium hydroxide solution was added dropwise with stirring at room temperature. did. The mixture was stirred as it was at room temperature for 1 hour, and a methanol solution of 1N trifluoromethanesulfonic acid was slowly added dropwise thereto until the pH reached 3.0. The gradually precipitated crystals were collected by filtration, washed with methanol, and dried to obtain 1.6 g of the target metal complex dye Dye-3-2.

12 Synthesis of Dye-3-3 The metal complex dye Dye-3-3 was synthesized according to the following scheme.

  Under a nitrogen atmosphere, 380 mg of Dye-3-2a which is an intermediate of Dye-3-2 and 3.2 g of potassium iodide were added to 15 mL of diglyme, and the mixture was stirred at 110 ° C. for 2 hours. After cooling to room temperature, 15 mL of water and 30 mL of ethyl acetate were added, extracted and separated, the resulting organic layer was concentrated, and the resulting black solid was purified by silica gel column chromatography to obtain Dye-3. Obtained 214 mg of -3a. This was hydrolyzed with an ester moiety in the same manner as Dye-3-2, to obtain the target metal complex dye Dye-3-3.

13. Synthesis of Dye-3-6 The metal complex dye Dye-3-6 was synthesized according to the following scheme.

  Under a nitrogen atmosphere, 320 mg of Dye-3-2a and 86 mg of silver trifluoromethanesulfonate were added to 10 mL of dichloromethane, and the mixture was heated to reflux for 3 hours. After cooling to room temperature, the resulting silver chloride precipitate was removed by celite filtration. Under a nitrogen atmosphere, 554 mg of p-tert-butylbenzenethiol and 337 mg of triethylamine were introduced into the filtrate, and the mixture was heated to reflux for 5 hours. After cooling to room temperature, 30 mL of water and 20 mL of dichloromethane were added, extracted and separated, the organic layer obtained was concentrated, and the resulting black solid was purified by silica gel column chromatography, so that Dye-3- 132 mg of 6a was obtained. This was hydrolyzed with an ester moiety in the same manner as Dye-3-2, to obtain the target metal complex dye Dye-3-6.

  Each metal complex dye synthesized as described above was confirmed by ESI-MS. The MS measurement results are shown in Table 1.

Example 2 [Dye-sensitized solar cell]
A dye-sensitized solar cell was produced by the following procedure.
A photoelectrode having the same configuration as that of the photoelectrode 12 shown in FIG. 5 described in JP-A-2002-289274 is prepared, and further, the photoelectrode is used and shown in FIG. 3 of the publication. A 10 mm × 10 mm scale dye-sensitized solar cell having the same configuration as the dye-sensitized solar cell 20 except for the photoelectrode was produced. A specific configuration is shown in FIG. 2 attached to the drawings of the present application. In FIG. 2 of the present application, 41 is a transparent electrode, 42 is a semiconductor electrode, 43 is a transparent conductive film, 44 is a substrate, 45 is a semiconductor layer, 46 is a light scattering layer, 40 is a photoelectrode, 20 is a dye-sensitized solar cell, CE is a counter electrode, E is an electrolyte, and S is a spacer.

(Preparation of paste)
(Paste A) A titania slurry was prepared by placing spherical TiO ₂ particles (anatase, average particle size; 25 nm, hereinafter referred to as spherical TiO ₂ particles A) in a nitric acid solution and stirring. Next, a cellulose binder as a thickener was added to the titania slurry and kneaded to prepare a paste.
(Paste 1) A titania slurry was prepared by stirring spherical TiO ₂ particles A and spherical TiO ₂ particles (anatase, average particle size: 200 nm, hereinafter referred to as spherical TiO ₂ particles B) in a nitric acid solution. . Next, a cellulose binder as a thickener was added to the titania slurry and kneaded to prepare a paste (mass of TiO ₂ particles A: mass of TiO ₂ particles B = 30: 70).
(Paste 2) The paste A is mixed with rod-like TiO ₂ particles (anatase, diameter: 100 nm, aspect ratio: 5, hereinafter referred to as rod-like TiO ₂ particles C), and the mass of the rod-like TiO ₂ particles C: the mass of the paste A = A 30:70 paste was prepared.

(Production of photoelectrode)
A transparent electrode in which a fluorine-doped SnO ₂ conductive film (film thickness: 500 nm) was formed on a glass substrate was prepared. Then, the paste 1 was screen-printed on the SnO ₂ conductive film and then dried. Then, it baked on the conditions of 450 degreeC in the air. Further, by repeating the firing and the screen printing using a paste 2, the semiconductor electrode (the area of the light receiving surface of the same structure as the semiconductor electrode 42 shown in FIG. 2 of the present application drawings on SnO ₂ conductive film; 10 mm × 10 mm Layer thickness: 16 μm, layer thickness of the dye adsorption layer: 12 μm, layer thickness of the light scattering layer: 4 μm, content of rod-like TiO ₂ particles C contained in the light scattering layer; 30% by mass) The photoelectrode which does not contain was produced.

(Dye adsorption)
Next, the pigment | dye was made to adsorb | suck to the semiconductor electrode which does not contain a pigment | dye as follows. First, anhydrous ethanol dehydrated with magnesium ethoxide was used as a solvent, and the metal complex dyes listed in Table 2 below were dissolved therein so as to have a concentration of 3 × 10 ⁻⁴ mol / L. Each dye solution was prepared by adding 20 mol of an equimolar mixture of chenodeoxycholic acid and cholic acid to 1 mol of the metal complex dye. When the water content of this dye solution was measured by Karl Fischer titration, the water content was less than 0.01% by mass. Next, the semiconductor electrode was immersed in this solution, pulled up and dried at 50 ° C. to complete the photoelectrode 10 in which the dye was adsorbed to the semiconductor electrode by about 1.5 × 10 ⁻⁷ mol / cm ² .

(Assembling solar cells)
Next, a platinum electrode (thickness of Pt thin film; 100 nm) having the same shape and size as the above-mentioned photoelectrode as the counter electrode CE, and an iodine redox solution containing iodine and lithium iodide as the electrolyte E were prepared. Further, a DuPont spacer S (trade name: “Surlin”) having a shape corresponding to the size of the semiconductor electrode is prepared, as shown in FIG. 3 described in JP-A-2002-289274. The dye-sensitized solar cells (sample Nos. 1 to 13 and c1 to c3) using the photoelectrode by filling the above electrolyte with the photoelectrode 40, the counter electrode CE, and the spacer S inside are completed. It was.
The performance of each dye-sensitized solar cell thus prepared was evaluated.

<Spectral sensitivity characteristics at wavelengths of 800 nm and 850 nm>
IPCE (quantum yield) at wavelengths of 300 to 1000 nm was measured with an IPCE measuring device manufactured by Pexel. Among these, IPCE at 800 nm and 850 nm was evaluated according to the following criteria.

Evaluation Criteria at 800 nm AA: 1.1 times or more with respect to Comparative Compound (1) A: 1.05 times or more and less than 1.1 times with respect to Comparative Compound (1) B: against Comparative Compound (1) 1.03 times or more and less than 1.05 times C: 1 time or more and less than 1.03 times with respect to the comparative compound (1) D: Evaluation standard at less than 1 time with respect to the comparative compound (1) at 850 nm AA: Comparative compound 1.3 times or more with respect to (1) A: 1.2 times or more and less than 1.3 times with respect to the comparative compound (1) B: 1.1 times or more and 1.2 times with respect to the comparative compound (1) Less than C: 1 to 1.1 times the comparative compound (1) D: Less than 1 time to the comparative compound (1)

<Evaluation of thermal degradation>
Each dye-sensitized solar cell was put in a constant temperature bath at 40 ° C. to conduct a heat resistance test. The current values of the dye-sensitized solar cell before the heat resistance test and the dye-sensitized solar cell after 12 hours of the heat resistance test were measured to evaluate the thermal deterioration of the dye-sensitized solar cell. The value obtained by dividing the decrease in the current value after the heat test by the current value before the heat test is defined as the thermal degradation rate, and the calculated thermal degradation rate is converted into the value for the following comparative compound (1). It was evaluated with.
In addition, in the conventional dye-sensitized solar cell, in view of the fact that the durability of the dye-sensitized solar cell is greatly improved when the thermal deterioration rate obtained as described above is improved by 2%, the following standards, particularly the standards The vicinity of the value was classified every 2%.

Evaluation Criteria AAA: 1.1 times or more with respect to Comparative Compound (1) AA: 1.06 times or more and less than 1.1 times with respect to Comparative Compound (1) A: 1.04 with respect to Comparative Compound (1) B: 1.02 times or more and less than 1.04 times with respect to the comparative compound (1) C: 1.00 times or more and less than 1.02 times with respect to the comparative compound (1) D: Comparative compound It is less than 1.00 times with respect to (1).

The comparative compounds (1) to (3) are metal complex dyes described below.
Comparative compound (1): Patent Document 2 described above
Comparative compound (2): Non-patent document 1 described above
Comparative compound (3): Patent Document 1 described above

As apparent from Table 2 above, as the ligand LD used together with the tridentate ligand LA, a nitrogen atom coordinated by a lone pair with respect to the metal ion M and further having an electron withdrawing atom is further added. A specific bidentate ligand formed by combining a nitrogen atom constituting a nitrogen-containing aromatic ring and a specific coordination atom coordinated to the metal ion M by an anion was used. Sample No. It was found that all of the dye-sensitized solar cells 1 to 13 were excellent in sensitivity characteristics and durability in a long wavelength region with respect to each dye-sensitized solar cell using the comparative compound.
Specifically, the sample No. is 800 nm and 850 nm. Each of the dye-sensitized solar cells 1 to 13 showed good photoelectric conversion efficiency with respect to each dye-sensitized solar cell using the comparative compound. Furthermore, the durability of the dye-sensitized solar cell evaluated by the above heat resistance test is good for each dye-sensitized solar cell using the comparative compound, and both the sensitivity characteristics and durability in the long wavelength region are compatible. Succeeded.

  The reason is not yet clear, but is estimated as follows. That is, by adopting a bidentate ligand having a more electron-deficient nitrogen-containing aromatic ring and a specific anion as the ligand LD coordinated to the metal ion M together with the ligands LA and LX, the metal It is considered that the lowest empty orbit (LUMO) of the complex dye becomes deep and the photoelectric conversion efficiency in the long wavelength region is improved. In addition, when such a ligand LD is coordinated, the nitrogen-containing aromatic ring is increased in π-acceptability from the metal ion M, and the bond between the metal ion M and the nitrogen-containing aromatic ring is strengthened. Coordination of a specific anion can effectively suppress thermal dissociation of the ligand LX. The durability of the metal complex dye and thus the photoelectric conversion element can be achieved by exerting a good balance between strengthening the bonding force between the metal ion M and the nitrogen-containing aromatic ring and suppressing thermal dissociation of the ligand LX. Can be improved.

DESCRIPTION OF SYMBOLS 1 Conductive support body 2 Photoconductor layer 21 Dye 22 Semiconductor fine particle 3 Charge transfer body layer 4 Counter electrode 5 Photosensitive electrode 6 Circuit 10 Photoelectric conversion element 100 System M using a photoelectrochemical cell Electric motor (electric fan)

20 Dye-sensitized solar cell 40 Photoelectrode 41 Transparent electrode 42 Semiconductor electrode 43 Transparent conductive film 44 Substrate 45 Semiconductor layer 46 Light scattering layer CE Counter electrode E Electrolyte S Spacer

Claims (15)

A photoelectric conversion element having a conductive support, a photoreceptor layer containing an electrolyte, a charge transfer layer containing an electrolyte, and a counter electrode,
The photoelectric conversion element in which this photoreceptor layer has the semiconductor fine particle by which the metal complex dye represented by following formula (I) was carry | supported.
M (LD) (LA) (LX) · (Y) n Formula (I)
[Wherein, M represents a metal ion.
LD represents a bidentate ligand represented by any of the following formulas (2L-1) to (2L-3).
LA represents a tridentate ligand represented by the following formula (AL-1) or (AL-2).
LX represents a monodentate ligand.
Y represents a counter ion necessary for neutralizing the electric charge. n represents an integer of 0 to 4. ]

[In the formula, * represents a bonding position to the metal ion M.
Ring D ¹ represents a nitrogen-containing aromatic ring, ring D ² represents an aromatic hydrocarbon ring or heteroaromatic ring. A ¹² and ^{A 13} are each ^{independently, N - R L,} O - or S ^- represents a. A ^{1 to} A ⁴ each independently represent CR ^LD or N, and at least one of A ^{1 to} A ⁴ represents N. L ^LD is -C (= O)-, -C (= S)-, -C (= NR ^L )-, -C (R ^L ) ₂ -and -C (= C (R ^L ) ₂ )- Represents a divalent linking group selected from the group consisting of R ^L and R ^LD each independently represent a hydrogen atom or a substituent that does not have the following Anc ¹ , Anc ^2, and Anc ³ . ]

[Wherein, Anc ^{1 to} Anc ³ each independently represent —CO ₂ H, —SO ₃ H, —PO ₃ H ₂ or a group in which any one of these protons is dissociated. R ^AL represents a substituent other than Anc ^{1 to} Anc ³ , and b1 represents an integer of 0 to 4. ] The photoelectric conversion element according to claim 1, wherein the M is Fe ²⁺ , Ru ²⁺ or Os ²⁺ . The photoelectric conversion element according to claim ^1, wherein ^{1 to} 3 of the A ^{1 to} A ⁴ are N. In the formulas (2L-1) to (2L-3), the ring represented by the following formula (2L _R ) formed by including the nitrogen atom bonded to the metal ion M and the A ^{1 to} A ⁴ structure is a compound represented by the following formula _{(2L R -1) ~ (2L} R -4) the photoelectric conversion device according to any one of claims 1 to 3 is a ring structure represented by any one of the.

[Wherein, R ^LDa represents a substituent not having the above Anc ¹ , Anc ² and Anc ³ , nL1 to nL3 each independently represents an integer of 0 to 3, and nL4 represents an integer of 0 to 2. ]   The photoelectric conversion element according to any one of claims 1 to 4, wherein a co-adsorbent having one or more acidic groups is further supported on the semiconductor fine particles. The photoelectric conversion element according to claim 5, wherein the adsorbent is represented by the following formula (CA).

[Wherein, R ^A1 represents a substituent having an acidic group. R ^A2 represents a substituent. nA represents an integer of 0 or more. ]   The dye-sensitized solar cell which has a photoelectric conversion element of any one of Claims 1-6. A metal complex dye represented by the following formula (I).
M (LD) (LA) (LX) · (Y) n Formula (I)
[Wherein, M represents a metal ion.
LD represents a bidentate ligand represented by any of the following formulas (2L-1) to (2L-3).
LA represents a tridentate ligand represented by the following formula (AL-1) or (AL-2).
LX represents a monodentate ligand.
Y represents a counter ion necessary for neutralizing the electric charge. n represents an integer of 0 to 4. ]

[In the formula, * represents a bonding position to the metal ion M.
Ring D ¹ represents a nitrogen-containing aromatic ring, ring D ² represents an aromatic hydrocarbon ring or heteroaromatic ring. A ¹² and ^{A 13} are each ^{independently, N - R L,} O - or S ^- represents a. A ^{1 to} A ⁴ each independently represent CR ^LD or N, and at least one of A ^{1 to} A ⁴ represents N. L ^LD is -C (= O)-, -C (= S)-, -C (= NR ^L )-, -C (R ^L ) ₂ -and -C (= C (R ^L ) ₂ )- Represents a divalent linking group selected from the group consisting of R ^L and R ^LD each independently represent a hydrogen atom or a substituent that does not have the following Anc ¹ , Anc ^2, and Anc ³ . ]

[Wherein, Anc ^{1 to} Anc ³ each independently represent —CO ₂ H, —SO ₃ H, —PO ₃ H ₂ or a group in which any one of these protons is dissociated. R ^AL represents a substituent other than Anc ^{1 to} Anc ³ , and b1 represents an integer of 0 to 4. ] In the formulas (2L-1) to (2L-3), the following ring structure (2L _R ) formed including the nitrogen atom bonded to the metal ion M and the A ^{1 to} A ⁴ is represented by the following formula: _{(2L R -1) ~ (2L} R -4) metal complex dye according to claim 8, which is a ring structure represented by any one of the.

[Wherein, R ^LDa represents a substituent not having the above Anc ¹ , Anc ² and Anc ³ , nL1 to nL3 each independently represents an integer of 0 to 3, and nL4 represents an integer of 0 to 2. ]   A dye solution obtained by dissolving the metal complex dye according to claim 8.   The dye solution according to claim 10, wherein 0.001 to 0.1% by mass of the metal complex dye is contained in an organic solvent, and water is suppressed to 0.1% by mass or less.   The dye solution according to claim 10 or 11, wherein the dye solution further contains a co-adsorbent having one or more acidic groups. The dye solution according to claim 12, wherein the co-adsorbent is represented by the following formula (CA).

[Wherein, R ^A1 represents a substituent having an acidic group. R ^A2 represents a substituent. nA represents an integer of 0 or more. ]   A dye obtained by applying a composition obtained from the dye solution according to any one of claims 10 to 13 to a conductive support, and curing the composition after application to form a photoreceptor layer. Dye adsorption electrode for sensitized solar cell.   The manufacturing method of the dye-sensitized solar cell which prepares the pigment | dye adsorption electrode of Claim 14, an electrolyte, and a counter electrode, and assembles using these.

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