JP5972849B2 - Metal complex, metal complex dye, photoelectric conversion element, dye-sensitized solar cell, dye solution, dye-adsorbing electrode, and method for producing dye-sensitized solar cell - Google Patents

Description

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

  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 its full-scale practical use is expected as an 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 results of Graetzel and others at the Swiss Lausanne University of Technology. 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, N3, N719, Z907, J2 and the like have been developed as metal complex dyes used for photoelectric conversion elements. However, conventional dye-sensitized solar cells generally have low photoelectric conversion efficiency and often have poor durability.

  Recently, there has been proposed a dye containing an anchor group having an ethenylene structure in the molecular structure, which exhibits strong absorption in the visible and long wavelength regions of the sunlight spectrum (see Patent Document 1).

Special table 2011-502187

  It is described that the dye proposed in Patent Document 1 exhibits absorption in the long wavelength region of the sunlight spectrum, and when employed in a photoelectric conversion element, the photoelectric conversion efficiency (η) can be improved over conventional dyes. Presumed to be possible. However, the required performance level for dye-sensitized solar cells is increasing year by year, and further improvement is demanded particularly in terms of improvement of photoelectric conversion efficiency (η).

  Therefore, the object of the present invention is to provide a metal complex dye exhibiting excellent performance in photoelectric conversion efficiency (η), a metal complex that is a synthetic intermediate of this metal complex dye, and an excellent performance by using this metal complex dye. The object is to provide a photoelectric conversion element, a dye adsorption electrode, a dye-sensitized solar cell, a method for producing the same, and a dye solution containing a metal complex dye.

In order to improve the photoelectric conversion efficiency (η), it is important for the present inventors to shift the absorption wavelength to the longer wavelength side and improve the molar extinction coefficient. It was considered effective to increase the vibrator strength as well as to increase the level of the lowest empty orbit (referred to as LUMO) of the metal complex dye.
As a result of investigation based on this assumption, a method for substitution of a ligand mother nucleus via a linking group of an anchor group adsorbed on a semiconductor fine particle and a tridentate ligand devised for the substitution mother nucleus and one or It has been found that when a bidentate ligand or a tridentate ligand in which two coordination atoms are anionic are used in combination, the photoelectric conversion efficiency in the long wavelength region is remarkably improved. 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, wherein the photoreceptor layer is represented by the following formula (I) A photoelectric conversion element having semiconductor fine particles carrying a dye.

(Where
M represents a metal ion.
Ring A, ring B and ring C each independently represent a nitrogen-containing aromatic heterocycle. Z ¹ and Z ² each independently represent a carbon atom or a nitrogen atom. Here, the bond between Z ¹ and the N atom and the bond between Z ² and the N atom may be a single bond or a double bond.
R ^{1 to} R ³ each independently represents a substituent having no Anc ¹ to Anc ³ . n1 and n3 each independently represents an integer of 0 to 4, and n2 represents an integer of 0 to 3. When a plurality of R ^{1 to} R ³ are present in each of them, they may be bonded to each other to form a ring.
X ¹ represents a linking group. X ² represents —O—, —S—, —NR ′ (R ′ represents a hydrogen atom or a substituent) —, a saturated aliphatic group, or an unsaturated aliphatic group having an unsaturated group that is not π-conjugated with the ring B. Represents a group, a non-aromatic hydrocarbon ring group, a non-aromatic heterocyclic group or a combination thereof. X ³ represents a single bond or a linking group. Anc1 to Anc3 each independently represents an acidic group. l1 and l3 each independently represent an integer of 1 to 4, and l2 represents an integer of 1 to 5, respectively.
m1 represents an integer of 1 to 4, m2 represents an integer of 0 to 3, and m3 represents an integer of 0 to 4, respectively.
L ^{1 to} L ³ each represents a ligand and is a bidentate ligand in which L ¹ and L ² are bonded to each other, or a tridentate ligand in which L ¹ , L ² and L ³ are bonded to each other. is there. Here, one or two of L ^{1 to} L ³ represents a ligand having an anionic coordination atom.
Y represents a counter ion necessary for neutralizing the charge, and n represents an integer of 0 to 2. )

(2) The photoelectric conversion element according to (1), wherein in formula (I), M is Fe ²⁺ , Ru ²⁺ or Os ²⁺ .
(3) In formula (I), ring A and ring C are each independently a pyridine ring, pyrimidine ring, triazine ring, imidazole ring, oxazole ring, thiazole ring, oxadiazole ring, thiadiazole ring, isoxazole ring, The photoelectric conversion element according to (1) or (2), which is an isothiazole ring, a triazole ring, or a pyrazole ring.
(4) The photoelectric conversion element according to any one of (1) to (3), wherein in formula (I), ring B is a pyridine ring or a pyrimidine ring.
(5) formula (I), Anc1～Anc3 each _{independently,} -COOH, -SO ₃ H, in any one of _-PO 3 H 2, is -OH or -SH (1) ~ (4) The photoelectric conversion element as described.

(6) In formula (I), at least one of X ¹ and X ³ is each independently represented by any one of the following formulas (3) to (10) or a combination thereof: ).

(In the formula, * represents a bonding position with ring A or ring C.
** represents a binding position with Anc1 or Anc3.
s represents the integer of 0-2.
R ^{31 to} R ¹⁰² represent a hydrogen atom or a substituent, and a plurality of substituents may be bonded directly or via a linking group to form a ring. )

(7) The photoelectric conversion element according to any one of (1) to (6), wherein in Formula (I), L ³ is an isothiocyanate ligand.
(8) A bidentate ligand in which the bidentate ligand in which L ¹ and L ² are bonded to each other in the formula (I) is represented by any one of the following formulas (2L-1) to (2L-5) The photoelectric conversion element according to any one of (1) to (7).

(In the formula, * represents a bonding position to the metal ion M.
Ring D represents an aromatic ring.
A ^{111 to} A ^{141 each} represents an anionic nitrogen atom or carbon atom, and A ¹⁵¹ represents any one of an anionic nitrogen atom, oxygen atom or sulfur atom. R ^{111 to} R ^{154 each} represent a hydrogen atom or a substituent having no Anc1, Anc2 and Anc3. )

(9) In the formula (I), a tridentate ligand in which L ¹ , L ² and L ³ are bonded to each other is represented by any of the following formulas (3L-1) to (3L-5) The photoelectric conversion element according to any one of (1) to (6), which is a ligand.

(In the formula, * represents a bonding position to the metal ion M.
Ring D represents an aromatic ring.
A ^{211 to} A ²⁴² represent a nitrogen atom or a carbon atom, and A ²⁵¹ and A ²⁵² represent a nitrogen atom, an oxygen atom, or a sulfur atom. However, at least one of A ²¹¹ and A ²¹² , A ²²¹ and A ²²² , A ²³¹ and A ²³² , A ²⁴¹ and A ²⁴² , and A ²⁵¹ and A ²⁵² is anionic. R ^{211 to} R ²⁵³ represent a hydrogen atom or a substituent that does not have Anc 1, Anc 2, and Anc 3. )

(10) A dye-sensitized solar cell including the photoelectric conversion element according to any one of (1) to (9).

(11) A metal complex dye represented by the following formula (I).

(Where
M represents a metal ion.
Ring A, ring B and ring C each independently represent a nitrogen-containing aromatic heterocycle. Z ¹ and Z ² each independently represent a carbon atom or a nitrogen atom. Here, the bond between Z ¹ and the N atom and the bond between Z ² and the N atom may be a single bond or a double bond.
R ^{1 to} R ³ each independently represents a substituent having no Anc ¹ to Anc ³ . n1 and n3 each independently represents an integer of 0 to 4, and n2 represents an integer of 0 to 3. When a plurality of R ^{1 to} R ³ are present in each of them, they may be bonded to each other to form a ring.
X ¹ represents a linking group. X ² represents —O—, —S—, —NR ′ (R ′ represents a hydrogen atom or a substituent) —, a saturated aliphatic group, or an unsaturated aliphatic group having an unsaturated group that is not π-conjugated with the ring B. Represents a group, a non-aromatic hydrocarbon ring group, a non-aromatic heterocyclic group or a combination thereof. X ³ represents a single bond or a linking group. Anc1 to Anc3 each independently represents an acidic group. l1 and l3 each independently represent an integer of 1 to 4, and l2 represents an integer of 1 to 5, respectively.
m1 represents an integer of 1 to 4, m2 represents an integer of 0 to 3, and m3 represents an integer of 0 to 4, respectively.
L ^{1 to} L ³ each represents a ligand and is a bidentate ligand in which L ¹ and L ² are bonded to each other, or a tridentate ligand in which L ¹ , L ² and L ³ are bonded to each other. is there. Here, one or two of L ^{1 to} L ³ represents a ligand having an anionic coordination atom.
Y represents a counter ion necessary for neutralizing the charge, and n represents an integer of 0 to 2. )

(12) A dye solution obtained by dissolving the metal complex dye described in (11).
(13) in an organic solvent, a dye solution according to the metal complex dye containing 0.001 to 0.1 wt%, and the content of water is Ru der 0.1 wt% (12).
(14) A dye-adsorbing electrode for a dye-sensitized solar cell, wherein the metal complex dye according to (11) is supported on the surface of the semiconductor fine particles .
(15) A method for producing a dye-sensitized solar cell, which is assembled by using the dye-adsorbing electrode, the electrolyte, and each material serving as a counter electrode according to (14).

(16) A metal complex represented by the following formula (II).

(Where
M represents a metal ion.
Ring A, ring B and ring C each independently represent a nitrogen-containing aromatic heterocycle. Z ¹ and Z ² each independently represent a carbon atom or a nitrogen atom. Here, the bond between Z ¹ and the N atom and the bond between Z ² and the N atom may be a single bond or a double bond.
R ^{1 to} R ³ each independently represents a substituent. n1 and n3 each independently represents an integer of 0 to 4, and n2 represents an integer of 0 to 3. When a plurality of R ^{1 to} R ³ are present in each of them, they may be bonded to each other to form a ring.
X ¹⁰ and X ³⁰ each independently represent a single bond or a linking group. X ²⁰ represents a single bond or —O—, —S—, —NR ′ (R ′ represents a hydrogen atom or a substituent) —, a saturated aliphatic group, an unsaturated group that does not π-conjugated with the ring B. A saturated aliphatic group, a non-aromatic hydrocarbon ring group, a non-aromatic heterocyclic group, or a combination thereof is represented.
G represents an aldehyde group or an acetal group which is represented by any one of the following structures and may have a substituent.
p1 represents an integer of 1 to 4, p2 represents an integer of 0 to 3, and p3 represents an integer of 0 to 4, respectively.
L ^{1 to} L ³ each represents a ligand, both of which are monodentate ligands, a bidentate ligand in which L ¹ and L ² are bonded to each other, or L ¹ , L ² and L ³ are bonded to each other Tridentate ligand. Here, one or two of L ^{1 to} L ³ represents a ligand having an anionic coordination atom.
Y represents a counter ion necessary for neutralizing the charge, and n represents an integer of 0 to 2. )

(In the formula, each R ^G independently represents an alkyl group. * Represents a bonding position with X ¹⁰ , X ²⁰ or X ^30. )

  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 heterocyclic ring may be further condensed to form a condensed ring.

  According to the present invention, a metal complex dye exhibiting excellent performance capable of improving photoelectric conversion efficiency (η), a metal complex which is a synthetic intermediate of this metal complex dye, and an excellent use of this metal complex dye A photoelectric conversion element and a dye adsorption electrode, a dye-sensitized solar cell and a method for producing the same, and a dye solution containing a metal complex dye can be provided.

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. 3 is a cross-sectional view schematically showing a dye-sensitized solar cell produced in Example 2. FIG. 2 is a chart of ¹ H-NMR spectrum of Compound (6), which is a synthetic intermediate of metal complex dye Dye-1 synthesized in Example 1. FIG. 2 is a chart of ¹ H-NMR spectrum of Compound (7) which is a synthetic intermediate of metal complex dye Dye-1 synthesized in Example 1. FIG. 2 is a chart of ¹ H-NMR spectrum of metal complex dye Dye-1 synthesized in Example 1. FIG. 2 is a chart of ¹ H-NMR spectrum of Compound (11), which is a synthetic intermediate of metal complex dye Dye-2 synthesized in Example 1. FIG. 2 is a chart of ¹ H-NMR spectrum of Compound (12) which is a synthetic intermediate of metal complex dye Dye-2 synthesized in Example 1. FIG. 2 is a chart of ¹ H-NMR spectrum of metal complex dye Dye-2 synthesized in Example 1. FIG. 2 is a chart of ¹ H-NMR spectrum of metal complex dye Dye-4 synthesized in Example 1. FIG. 2 is an ultraviolet-visible spectrum chart of the metal complex dye Dye-1 synthesized in Example 1. FIG. 2 is a chart of an ultraviolet-visible spectrum of the metal complex dye Dye-2 synthesized in Example 1. FIG. 2 is a chart of an ultraviolet-visible spectrum of the metal complex dye Dye-4 synthesized in Example 1. FIG. 2 is a chart of an ultraviolet-visible spectrum of the metal complex dye Dye-5 synthesized in Example 1. FIG. 2 is a chart of an ultraviolet-visible spectrum of the metal complex dye Dye-6 synthesized in Example 1. FIG. It is a visible absorption spectrum figure of the titanium oxide film which made the metal complex pigment | dye Dye-1 synthesize | combined in Example 1 adsorb | suck to titanium oxide. It is a visible absorption spectrum figure in the titanium oxide film | membrane which made the metal complex pigment | dye Dye-5 synthesize | combined in Example 1 adsorb | sucked to titanium oxide. It is a visible absorption spectrum figure in the titanium oxide film | membrane which made the metal complex pigment | dye Dye-6 synthesize | combined in Example 1 adsorb | sucked to titanium oxide.

<< 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. 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 materials 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. 5,084,365, U.S. Pat.No. 5,350,644, U.S. Pat. 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.

<Photoreceptor layer>
The photoreceptor layer is a layer containing semiconductor fine particles containing an electrolyte described later and carrying a sensitizing dye containing the metal complex dye of the present invention described below.

<< metal complex dye >>
The metal complex dye of the present invention is represented by the following formula (I).

In the formula, M represents a metal ion.
Ring A, ring B and ring C each independently represent a nitrogen-containing aromatic heterocycle. Z ¹ and Z ² each independently represent a carbon atom or a nitrogen atom. Here, the bond between Z ¹ and the N atom and the bond between Z ² and the N atom may be a single bond or a double bond.
R ^{1 to} R ³ each independently represents a substituent having no Anc ¹ to Anc ³ . n1 and n3 each independently represents an integer of 0 to 4, and n2 represents an integer of 0 to 3. When a plurality of R ^{1 to} R ³ are present in each of them, they may be bonded to each other to form a ring.
X ¹ represents a linking group. X ² represents —O—, —S—, —NR ′ (R ′ represents a hydrogen atom or a substituent) —, a saturated aliphatic group, or an unsaturated aliphatic group having an unsaturated group that is not π-conjugated with the ring B. Represents a group, a non-aromatic hydrocarbon ring group, a non-aromatic heterocyclic group or a combination thereof. X ³ represents a single bond or a linking group. Anc1 to Anc3 each independently represents an acidic group. l1 and l3 each independently represent an integer of 1 to 4, and l2 represents an integer of 1 to 5, respectively.
m1 represents an integer of 1 to 4, m2 represents an integer of 0 to 3, and m3 represents an integer of 0 to 4, respectively.
L ^{1 to} L ³ each represents a ligand and is a bidentate ligand in which L ¹ and L ² are bonded to each other, or a tridentate ligand in which L ¹ , L ² and L ³ are bonded to each other. is there. Here, one or two of L ^{1 to} L ³ represents a ligand having an anionic coordination atom.
Y represents a counter ion necessary for neutralizing the charge, and n represents an integer of 0 to 2.

Metal complex dye of the formula (I), the linking groups X ¹ and an acid group Anc1 has at least one linked ring A, a tridentate ligand consisting of ring A, ring B and ring C, distribution The coordination atom has ligands L ^{1 to} L ³ containing one or two anionic ligands. The metal complex dye having such a structure greatly increases the photoelectric conversion efficiency (η) and is excellent in reducing adsorption stability and performance.

  The metal complex dye represented by the formula (I) is represented by the following formula (I-1) when m3 is an integer of 1 to 4, and is represented by the following formula (I-2) when m3 is 0. The

In the formula, M, ring A to ring C, Z ¹ , Z ² , R ^{1 to} R ³ , n1 to n3, X ^{1 to} X ³ , Anc1 to Anc3, l1 to l3, m1 and m2, L ^{1 to} L ³ , Y and n have the same meanings as in formula (I), and preferred ranges are also the same. m31 is an integer of 1-4.

Metal complex dye of the formula (I-1) has only to have a Anc3 and linking groups ^{X 3} in at least one ring C a Anc1 and linking groups ^{X 1} to the ring A, ring B is linked it may or may not have a group ^{X 2} and Anc2. Since the metal complex dye represented by the formula (I-1) has at least one Anc1 and at least one Anc3 as acidic groups, it is strongly adsorbed by the semiconductor fine particles. Therefore, this metal complex dye exhibits a still higher photoelectric conversion efficiency (η) and is excellent in durability and reduction in variation in performance.
Metal complex dye represented by formula (I-2) may have at least one of Anc1 and linking groups ^{X 1} to the ring A, ring B, which may have a linking group ^{X 2} and Anc2 It does not have to be.

− Metal ion M −
M is a central metal of the metal complex dye, and examples thereof include elements of groups 6 to 12 on the long periodic table.
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⁺ , Fe ²⁺ or Cu ^2+, more preferably Os ²⁺ , Ru ²⁺ and Fe ²⁺ , more preferably Os ²⁺ and Ru ²⁺ , and particularly preferably Ru ²⁺ .
In addition, in the state incorporated in the photoelectric conversion element, the valence of M may be changed by an oxidation-reduction reaction with surrounding materials.

− Acceptor ligand −
In the formula (I), the tridentate ligand formed by connecting the ring A, the ring B, and the ring C to each other has an adsorbing group (also referred to as an acidic group) that is adsorbed on the surface of the semiconductor fine particles. This ligand may be referred to as an “acceptor ligand”. Hereinafter, this acceptor ligand will be described.

[Ring A, Ring B and Ring C]
Ring A, Ring B, and Ring C are each a nitrogen-containing aromatic heterocycle, and each ring-constituting atom is connected to each other without using a linking group to form a tridentate as an acceptor ligand. Ligand is formed. Here, the nitrogen atom constituting ring A and ring C and bonded to metal ion M may be an anion, but preferably has a lone pair of electrons. In Ring A and Ring C, Z ¹ and Z ² represent a carbon atom or a nitrogen atom, and the bond between Z ¹ and N atom in Ring A and the bond between Z ² and N atom in Ring C are Independently, each may be a single bond or a double bond. Ring A and ring C are connected to ring B by these Z ¹ and Z ² . Z ¹ and Z ² are particularly preferably both carbon atoms.

Ring A, ring B, and ring C may each be any nitrogen-containing aromatic heterocycle as long as it can bind to metal ion M. Such a nitrogen-containing aromatic heterocycle is preferably a 5-membered ring or a 6-membered ring. These nitrogen-containing aromatic heterocycles may be other rings, for example, an aryl group or a heterocyclic group of the substituent T described later, or a non-aromatic heterocyclic group ring or a non-aromatic hydrocarbon ring group described later. It does not matter if it is condensed. Further, the ring-constituting heteroatoms of the nitrogen-containing aromatic heterocycle may be 2 to 6 nitrogen atoms, or may contain other heteroatoms such as oxygen atoms and sulfur atoms in addition to the nitrogen atoms.
Examples of the 6-membered nitrogen-containing aromatic heterocycle include a pyridine ring, pyrimidine ring, pyridazine ring, pyrazine ring, triazine ring, quinoline ring, isoquinoline ring, and quinazoline ring, and a 5-membered nitrogen-containing aromatic ring. Examples of the heterocycle include a pyrrole ring, an imidazole ring, a pyrazole ring, an oxazole ring, a thiazole ring, a benzimidazole ring, a benzoxazole ring, a benzothiazole ring, an indoline ring, an indazole ring, a triazole ring, a tetrazole ring, an isoxazole ring, Examples include isothiazole ring, furazane ring, indole ring, benzopyrrole ring, isoindole ring, benzotriazole ring, oxadiazole ring, and thiadiazole ring.

Ring A and ring C are preferably a non-condensed 5- or 6-membered ring or a condensed (preferably benzene-fused) 5-membered ring having a lone electron pair that is not conjugated to the π electron of ring A or ring C. An aromatic heterocycle is particularly preferred. Examples of the nitrogen-containing aromatic heterocycle having a lone pair of electrons include a pyridine ring, pyrimidine ring, triazine ring, imidazole ring, oxazole ring, thiazole ring, benzothiazole ring, oxadiazole ring, thiadiazole ring, isoxazole ring, Examples include isothiazole ring, triazole ring, pyrazole ring, pyridine ring, pyrimidine ring, triazine ring, imidazole ring, oxazole ring, thiazole ring, oxadiazole ring, thiadiazole ring, isoxazole ring, isothiazole ring, triazole ring. The pyrazole ring is preferred.
Ring B is preferably a non-condensed 6-membered ring, for example, a pyridine ring, a pyrazine ring, a pyrimidine ring or a triazole ring is more preferred, and a pyridine ring or a pyrimidine ring is particularly preferred.

At least one of Z ¹ and Z ² is preferably a carbon atom, and more preferably both are carbon atoms. When Z ¹ or Z ² is a nitrogen atom, ring A or ring C is preferably a pyrazole ring or a triazole ring, respectively.

  Ring A, ring B and ring C may be the same or different from each other, and ring A and ring C may be different but are preferably the same. Examples of combinations of ring A, ring B and ring C include, for example, ring A-ring B-ring C in this order: pyridine ring-pyridine ring-pyridine ring, pyridine ring-pyridine ring-pyrimidine ring, pyridine ring-pyridine ring- Benzothiazole ring, pyridine ring-pyridine ring-imidazole ring, pyridine ring-pyrimidine ring-pyridine ring, pyrimidine ring-pyridine ring-pyrimidine ring, triazine ring-pyridine ring-triazine ring, pyridine ring-pyrazine ring-pyridine ring, pyridine Ring-pyridine ring-pyrazine ring, pyrazine ring-pyridine ring-pyrazine ring, pyridine ring-pyridine ring-pyrazole ring, etc., among others, pyridine ring-pyridine ring-pyridine ring, pyridine ring-pyridine ring-pyrimidine ring Pyridine ring-pyridine ring-benzothiazole ring, pyridine ring-pyridine ring-imidazole Ring, pyridine ring - pyrimidine ring - pyridine ring are preferred, pyridine ring - pyridine ring - pyridine ring is more preferable.

[Substituents R ¹ , R ² and R ³ ]
Ring A, ring B, and ring C may have substituents R ¹ , R ^2, and R ³ that do not have Anc ¹ , Anc 2, and Anc 3, respectively. The substituent ^R 1, ^{R 2} and ^{R 3} in which the ring A~C have each independently include substituents T.

<Substituent T>
Examples of the substituent T include the following. In addition, in this specification, what is described only as a substituent refers to this substituent T, and when each group, for example, an alkyl group is only described, Preferred ranges and specific examples of the corresponding group of the substituent T are applied.

  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 and the like), a heterocyclic group (preferably having 2 to 20 carbon atoms and having at least one oxygen atom, sulfur atom or nitrogen atom) A heterocyclic group of a ring is more preferable, for example, 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzoimidazolyl, 2-thiazolyl, 2-oxazolyl and the like, an alkoxy group (preferably having 1 to 20 carbon atoms, , Methoxy, ethoxy, isopropyloxy, benzyloxy, etc.), 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 -Propynyloxy, 4-butynyloxy, etc.), cycloalkyloxy groups (preferably A prime number of 3 to 20, for example, cyclopropyloxy, cyclopentyloxy, cyclohexyloxy, 4-methylcyclohexyloxy and the like, an aryloxy group (preferably having a carbon number of 6 to 26, for example, phenoxy, 1-naphthyloxy, 3- Methylphenoxy, 4-methoxyphenoxy, etc.), 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) Groups such as methanesulfonamide, benzenesulfonamide, N-methylmethanesulfonamide, N-cyclohexylsulfonamide, N-ethylbenzenesulfonamide, etc., alkylthio groups (preferably having 1 to 20 carbon atoms, for example methylthio , Ethylthio, isopropylthio, benzylthio, etc.), cycloalkylthio group (preferably having 3 to 20 carbon atoms, such as cyclopropylthio, cyclopentylthio, cyclohexylthio, 4-methylcyclohexylthio Etc.), an arylthio group (preferably having 6 to 26 carbon atoms, such as phenylthio, 1-naphthylthio, 3-methylphenylthio, 4-methoxyphenylthio, etc.), alkyl, cycloalkyl or arylsulfonyl group (preferably having a carbon number) 1-20, 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 (eg fluorine atom, chlorine atom, bromine atom, iodine atom), carboxyl group, sulfo group, phosphonyl group, phosphoryl group, boric acid group, more preferably alkyl group An alkenyl group, a cycloalkyl group, an aryl group, a heterocyclic group, an alkoxy group, a cycloalkoxy group, an aryloxy group, an alkoxycarbonyl group, a cycloalkoxycarbonyl group, the amino group, an acylamino group, a cyano group, or a halogen atom, An alkyl group, an alkenyl group, a heterocyclic group, an alkoxy group, an alkoxycarbonyl group, an amino group, an acylamino group, or a cyano group is preferable.

  Further, the substituent T may be a group formed by combining a plurality of the aforementioned groups. For example, an aryl group substituted with one or more alkoxy groups, an aryl group or heterocyclic group having one or more alkyl groups, and an aryl group or heterocyclic group having one or more alkyl groups And alkenyl groups.

  When the substituent T or the compound contains an alkyl group, an alkenyl group or the like, 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.

As the substituents R ¹ , R ² and R ³ , an alkyl group, an alkenyl group, an aryl group, a heterocyclic group, a cyano group and a halogen atom are preferable, and an alkyl group, an alkenyl group and an aryl group are particularly preferable. When a plurality of substituents R ^{1 to} R ³ are present in each, they may be bonded to each other directly or via a linking group to form a ring.

[N1-n3]
In formula (I), n1 and n3 each independently represent an integer of 0 to 4, and n2 represents an integer of 0 to 3. n1 to n3 are preferably 0 or 1.

[Linking groups X ¹ and X ³ ]
Linking group X ¹ is a linking group, connecting the ring with A bonded atoms ANC1. On the other hand, X ³ is a single bond or a linking group, and connects the bond atom of Anc ³ and the ring C. Here, X ¹ and X ³ are synonymous except for whether or not a single bond is included, and preferable ones are also the same, so the linking group in X ¹ and X ³ will be described below.

The valence of the linking groups X ¹ and X ³ varies depending on the number of substitutions of the acidic groups Anc1 and Anc3 and the number of substitutions of the substituents R ¹ and R ³ and is at least divalent. Such a linking group is not particularly limited, and examples thereof include an acyclic hydrocarbon group having an unsaturated bond or a cyclic hydrocarbon group having an unsaturated bond, a non-aromatic heterocyclic group, and an aromatic heterocyclic group. Can be mentioned. Specific examples of the acyclic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, and the cyclic hydrocarbon group having an unsaturated bond includes a non-aromatic hydrocarbon ring group. And aromatic hydrocarbon ring groups. The linking groups X ¹ and X ³ can be expected to have an effect of improving the absorption characteristics due to the extension of the π-conjugated system. The linking group is preferably a linking group comprising a conjugated chain that is π-conjugated. Therefore, the linear or branched aliphatic hydrocarbon group, non-aromatic hydrocarbon ring group and non-aromatic heterocyclic group preferably have an unsaturated bond at a position π-conjugated with ring A or ring C. In addition, the aromatic hydrocarbon ring group and the aromatic heterocyclic group are preferably on the same plane as the ring A or ring C to be bonded and π-conjugated.

  Examples of the linear or branched aliphatic hydrocarbon group include an aliphatic hydrocarbon group having one or more carbon-carbon double bonds and / or carbon-carbon triple bonds. Suitable aliphatic hydrocarbon groups include, for example, hydrocarbon groups having one or more carbon-carbon double bonds, hydrocarbon groups having one or more carbon-carbon triple bonds, and the like. . Examples of the hydrocarbon group having one carbon-carbon double bond include an alkenylene group represented by the formula (3) described later, for example, ethenylene group. Examples of the hydrocarbon group having two or more carbon-carbon double bonds include hydrocarbon groups having an even number of π-conjugated methine chains as a skeleton, for example, hydrocarbons represented by formulas (4) to (6) described later. Groups. Examples of the hydrocarbon group having one carbon-carbon triple bond include alkynylene groups such as an ethynylene group.

  Examples of the non-aromatic hydrocarbon ring group include a hydrocarbon ring group having one or more carbon-carbon double bonds or carbon-carbon triple bonds so as not to satisfy the Hückel rule. In addition, when the ring-constituting atom contains an oxo group (> C═O), it can take an enol structure as a tautomer and formally, for example, 6π conjugate, but these are classified as non-aromatic hydrocarbon ring groups. . Suitable non-aromatic hydrocarbon ring groups include, for example, cycloalkenylene groups having one or more carbon-carbon double bonds, cycloalkynylene groups having one or more carbon-carbon triple bonds, etc. Is mentioned. Examples of the cycloalkenylene group and the cycloalkynylene group include a cycloalkenylene group and a cycloalkynylene group having 4 to 6 carbon atoms constituting the ring. In addition, since the carbon atom couple | bonded with the ring A or the ring C in a non-aromatic hydrocarbon ring group is a carbon atom which forms a carbon-carbon double bond or a carbon-carbon triple bond, since (pi) conjugated system can be extended, it is preferable. .

  Examples of the aromatic hydrocarbon ring group include a divalent or higher valent group corresponding to the aryl group of the substituent T, and specific examples include a benzene ring group and a naphthalene ring group.

  Examples of the non-aromatic heterocyclic group include a heterocyclic group having one or two or more carbon-carbon double bonds and / or carbon-hetero double bonds and not satisfying the Hückel rule, such as a pyrroline ring group. , An imidazoline ring group, a heterocyclic group represented by the following formula, and the like. As in the case of the non-aromatic hydrocarbon ring group, the case where the ring-constituting atom of the non-aromatic heterocyclic group includes an oxo group (> C═O) is also classified as a non-aromatic heterocyclic group. An atom bonded to ring A or ring C in a non-aromatic heterocyclic group (for example, a carbon atom marked with “*” or “**” in a heterocyclic group represented by the following formula) is carbon-carbon. A carbon atom or a hetero atom forming a double bond or a carbon-hetero double bond is preferable because the π-conjugated system can be extended.

Wherein * and ** represent the binding position of the ring A or ring C or Anc1 or ^{Anc3, R 11} and ^{R 12} represents a substituent. Examples of the substituent R ¹¹ include the substituent T, and examples of the substituent R ¹² include an electron-withdrawing group among the substituent T. For example, a cyano group is preferable.

  Examples of the aromatic heterocyclic group include a divalent or higher valent group corresponding to the nitrogen-containing aromatic heterocyclic ring of ring A to ring C and a divalent or higher valent group corresponding to the heterocyclic group of substituent T. Specifically, a bivalent or higher-valent aromatic heterocyclic group corresponding to a pyridine ring, a pyrimidine ring, a triazine ring, a triazole ring, a pyrazole ring, or the like, or a group having a thiophene ring structure (thiophene ring group, benzothiophene ring group, thiophene) A 1-oxide cyclic group, a thiophene 1,1-dioxide cyclic group, etc.) and a furan cyclic group corresponding to a divalent or higher valent aromatic heterocyclic group.

The linking groups X ¹ and X ³ may be a linking group formed by combining a plurality of the linking groups described above (hereinafter sometimes referred to as a composite linking group). Such a composite linking group includes, for example, a bond linking group formed by bonding a plurality of the linking groups, a substituted linking group in which the linking group is substituted with at least one substituent that does not have Anc1, Anc2, and Anc3. Can be mentioned. These composite linking groups are preferably π-conjugated with ring A or ring C.

  Examples of the bond linking group include a bond linking group in which a linear or branched aliphatic hydrocarbon group is bonded to an aromatic hydrocarbon ring group or an aromatic heterocyclic group, and a bond in which aromatic heterocyclic groups are bonded to each other. Examples thereof include a linking group. Examples of such a linking group include a group having a benzene ring group in which a hydrogen atom is substituted with an ethenylene group or an ethynylene group, a group having a thiophene ring structure, or a group having two or more thiophene ring structures. It is done. In these bonded linking groups, the linking group bonded to the acidic group may be an ethenylene group or an ethynylene group, or may be a group having a benzene ring group or a thiophene ring structure. Examples of the substituent of the substituted linking group include a substituent T. When m3 is 0, the substituent T is electron withdrawing (for example, a substituted or unsubstituted alkylcarbonyl group, a substituted or unsubstituted arylcarbonyl group, a substituted group). Or an unsubstituted aminocarbonyl group, a substituted or unsubstituted alkylsulfonyl group, a substituted or unsubstituted arylsulfonyl group, a substituted or unsubstituted aminosulfonyl group, or a cyano group), and when m3 is 1 or more The substituent T is preferably a hydrogen atom. The reason is that the photoelectric conversion efficiency is improved and the variation in performance can be reduced.

The linking groups X ¹ and X ³ are linear or branched unsaturated aliphatic hydrocarbon groups, aromatic heterocyclic groups, or these, in that the metal complex dye exhibits a higher photoelectric conversion efficiency (η). It is preferably a composite linking group. Among straight-chain or branched-chain aliphatic hydrocarbon groups, hydrocarbon groups having an even number of π-conjugated methine chains represented by the following formulas (3) to (6) are preferred, and the formula (3) is More preferred. Among the aromatic heterocyclic groups, an aromatic 5-membered heterocyclic group is preferable, a furan ring and a thiophene ring are more preferable, and a group having a thiophene ring skeleton represented by the following formulas (7) to (9). Is more preferable.

The linking groups X ¹ and X ³ are also preferably a composite linking group represented by the formula (3) and the following formulas (7) to (10). The composite linking group of the formula (3) and the following formula (7) Is more preferable, and as a composite order, a composite linking group in which ** of the formula (7) is bonded to * of the formula (3) is more preferable.

In the formula, * represents a bonding position to ring A or ring C, and ** represents a bonding position to Anc1 or Anc3. s represents the integer of 0-2. R ^{31 to} R ¹⁰² represent a hydrogen atom or a substituent, and a plurality of substituents may be bonded directly or via a linking group to form a ring. ^Here, as examples of substituents of R ^{31 to R 102} may be exemplified the substituent T.

[Linking group X ² ]
The linking group X ² is a group that links the ring B and Anc2, and includes, for example, —O—, —S—, —NR ′ (R ′ represents a hydrogen atom or a substituent) —, a saturated aliphatic group, It is a group formed by an unsaturated aliphatic group having an unsaturated group that is not π-conjugated with ring B, a non-aromatic hydrocarbon ring group, a non-aromatic heterocyclic group, or a combination thereof. Here, R ′ can include a hydrogen atom or the above-described substituent T. The connecting group X ² may have a substituent T.

In linking groups X ^2, saturated aliphatic group may be linear, branched or cyclic. A particularly preferred saturated aliphatic group is an alkylene group, and specific examples include an alkylene group having 1 to 6 carbon atoms such as a methylene group, an ethylene group, a propylene group, and a butylene group.
The unsaturated aliphatic group having an unsaturated group that is not π-conjugated with ring B only needs to have an unsaturated group that is not π-conjugated with an atom bonded to Anc2 and ring B. For example, one or two or more In the position where the ring B is not π-conjugated. As an unsaturated bond, a carbon-carbon double bond and / or a carbon-carbon triple bond are mentioned, for example. Examples of such a group include unsaturated aliphatic groups in which the carbon atom bonded to ring B is a carbon atom having an sp ³ hybrid orbital, that is, a saturated carbon atom. The unsaturated group of the unsaturated aliphatic group may or may not be π-conjugated with another unsaturated group as long as it is not π-conjugated with ring B. Specific examples of the particularly preferred unsaturated aliphatic group include alkenylene groups having 3 or more carbon atoms, alkynylene groups having 3 or more carbon atoms, and the like. Examples of the alkenylene group having 3 or more carbon atoms include 1-propenylene group (—CH═CH—CH ₂ —) and the like, and examples of the alkynylene group having 3 or more carbon atoms include 1-propynylene group (—C ≡C—CH ₂ —) and the like. In these alkenylene group and alkynylene group, the carbon atom bonded to the ring B is a carbon atom having an sp ³ hybrid orbital as described above, for example, a methylene carbon atom.

Non-aromatic hydrocarbon ring group, the a same meaning as the non-aromatic hydrocarbon ring group of the linking group X ¹ and X ^3, it is preferable also the same.
The non-aromatic heterocyclic group is synonymous with the non-aromatic heterocyclic group in the linking groups X ¹ and X ³ , and preferred ones are also the same.

Group formed by the combination include groups formed by combining the groups described as the linking group X ² 1 or more.

In the linking group X ² , even if the atom bonded to the ring B is a carbon atom or heteroatom forming a carbon-carbon double bond or a carbon-hetero double bond, other atoms such as sp ^It may be a carbon atom having ^three hybrid orbitals.

[Acid groups Anc1, Anc2 and Anc3]
In formula (I), the acidic groups represented by Anc1, Anc2 and Anc3 are substituents having a dissociative proton, and are groups having a pKa of 11 or less. For _{example, -COOH, -SO 3 H, -PO} 3 H 2, include an acidic group exhibiting acidity, such as -OH or -SH. Further, the acidic group may take a form of releasing a proton and dissociating, or may be a salt. The acidic group is preferably —COOH, —SO ₃ H, —PO ₃ H _2, —OH or —SH, or a salt thereof. When the acidic group is a salt, the counter ion when the salt is converted is not particularly limited, and examples thereof include positive ions represented by counter ion Y in formula (I). Anc1, Anc2 and Anc3 are each preferably —COOH or —OH, more preferably —COOH from the viewpoints of adsorption stability and electron injection.

  Further, as a preferred embodiment of the acidic group, the following formula (Anc) can be exemplified.

In the formula, Zx represents a single bond or-[C (= W ³ )] nx-. Here, nx represents an integer of 1 to 3. = W ¹ , = W ² and = W ³ each independently represent = O or = C (Ra1) (Ra2). Ra1 and Ra2 each independently represent a substituent. In addition, -OH in the above formula may form a salt.

In the formula (Anc), examples of the substituent of Ra1 and Ra2 in = C (Ra1) (Ra2) in W ^{1 to} W ³ include the substituent T described above. Ra1 and Ra2 are more preferably an alkyl group, an aryl group, a heterocyclic group, a cyano group, an acyl group, a sulfonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, or a sulfamoyl group, and an alkyl group, an aryl group, or a cyano group is more preferable. Further preferred.

  The group represented by the formula (Anc) is preferably a group represented by any one of the following formulas (Anc-1) to (Anc-5).

  In the formula, Ra1 to Ra4 each independently represent a substituent. -OH in the above formula may form a salt.

The substituents in Ra1 to Ra4 have the same meanings as Ra1 and Ra2 described above, and the preferred ranges are also the same.
Of the groups represented by the formulas (Anc-1) to (Anc-5), groups represented by the formulas (Anc-1) and (Anc-5) are preferable, and represented by the formula (Anc-1). Group is particularly preferred

  The metal complex dye represented by the formula (I) of the present invention has a plurality of acidic groups essentially including at least one Anc1 from the viewpoint of adsorption stability, that is, durability and reduction in performance variation. It is preferable that the plurality of acidic groups may be bonded to the same linking group or ring, or may be bonded to another linking group or ring. As an embodiment having a plurality of acidic groups, for example, the ring A may have a plurality of Anc1s, and in addition to Anc1, it may have Anc2 or Anc3. Preferably, ring A has at least one Ancl and ring C has at least one Anc3.

[L1-l3]
In formula (I), l1 and l3 each independently represent an integer of 1 to 4, and l2 represents an integer of 1 to 5. l1 and l3 are preferably each independently 1 or 2, and l2 is preferably 1 or 2.

[M1-m3 and m31]
In formula (I), m1 represents an integer of 1 to 4, m2 represents an integer of 0 to 3, and m3 represents an integer of 0 to 4. metal complex dye when m3 is an integer from 1 to 4 are represented by the formula (I-1), the linking group ^{X 3} and Anc3 coupled to the linking group ^{X 1} and Anc1 and ring C is connected to the ring A is essential It becomes. The reason is as described above. When m3 is 0, the metal complex dye is represented by the formula (I-2). linking groups ^{X 1} and Anc1 linked to ring A is required if m3 is 0. The reason is as described above. m1 is preferably 1, m2 is preferably 0 to 2, 0 is more preferably 1, 0 is more preferable, and m3 is preferably 1. m31 represents an integer of 1 to 4, and 1 is preferable.

  Specific examples of the ligand represented by the formula (I) of the present invention are shown below, but the present invention is not limited thereto.

  These ligands are disclosed in JP2012-508227A, JP2011-502965A, JP2011-502187A, Angew. Chem. Int. Ed. , 2011, 50, 1-6, the method described in the reference cited in the literature, or a method according to these methods.

-Ligands L ¹ , L ² and L ^3-
In the present invention, L ¹ , L ² and L ³ represent ligands and are bidentate ligands in which L ¹ and L ² are bonded to each other, or L ¹ , L ² and L ³ are bonded to each other It is a tridentate ligand. The ligands L ^{1 to} L ³ are all ligands having no acidic group, and are also referred to as “donor ligands”. When a bidentate ligand in which L ¹ and L ² are bonded to each other or a tridentate ligand in which L ¹ , L ² and L ³ are bonded to each other is used in combination with the acceptor ligand, a long wavelength region The photoelectric conversion efficiency is greatly increased. L ¹ , L ^2, and L ³ each represent a ligand that binds to the metal ion M, and one or two of L ^{1 to} L ³ are ligands having an anionic coordination atom. For example, when L ¹ and L ² are bidentate ligands bonded to each other, at least one of the coordination atoms is anionic, and L ¹ , L ² and L ³ are bonded to each other. When it is a tridentate ligand, one or two of the coordination atoms are anionic. When one or two of the ligands are ligands having an anionic coordination atom, the level of the highest occupied orbital and the lowest unoccupied orbital of the metal complex dye is moderated, and preferable absorption characteristics are exhibited. Or the effect that a voltage becomes high can be expected. As a result, the photoelectric conversion efficiency of the photoelectric conversion element is improved. In particular, it is preferable that the ligands L ¹ , L ² and L ³ have a conjugated structure in that the photoelectric conversion efficiency of the photoelectric conversion element is further increased.

As the ligands L ¹ , L ² and L ³ ,
(La) a nitrogen-containing aromatic ring group in which an atom bonded to the metal ion M has a lone electron pair and has no anionic property;
(Lb) a nitrogen-containing aromatic ring group having an anionic nitrogen atom as a ring constituent atom bonded to the metal ion M;
(Lc) An aromatic ring group other than a nitrogen-containing aromatic ring group (Lb) having an anionic carbon atom as a ring constituent atom bonded to the metal ion M (Ld) an anionic nitrogen atom, oxygen atom or sulfur atom An aromatic hydrocarbon ring group substituted with a functional group having,
(Le) a nitrogen-containing aromatic ring group substituted with a functional group having an anionic nitrogen atom, oxygen atom or sulfur atom, and
(Lf) Examples include ligands other than (La) to (Le).

These ligands (La) to (Lf) are linked in the same or different form to form a bidentate or tridentate ligand, preferably a bidentate or tridentate arrangement in which they are linked by a single bond. It is a rank.
In addition, these ligands may have a substituent which does not inhibit the characteristics of each ligand. Examples of such a substituent include a substituent other than the adsorptive group adsorbed on the surface of the semiconductor fine particles, and examples thereof include a substituent T. Specifically, the nitrogen-containing aromatic ring group (La) may have a substituent T that is not anionic. Preferred examples of the substituent T include an alkyl group, an alkenyl group, a perfluoroalkyl group, an alkoxy group, an aryl group, a heterocyclic group, a cyano group, a nitro group, a halogen atom, and a group formed by combining a plurality of these. It is. This substituent T may be bonded to each of two adjacent rings and condensed with them.

As the nitrogen-containing aromatic ring group (La) in which the atom bonded to the metal ion M has a lone electron pair and has no anionic property, at least one of the ring constituent atoms has a nitrogen atom having a lone electron pair, As a ring constituent atom, in addition to a nitrogen atom, an oxygen atom, a sulfur atom (—S—, —SO—, —SO ₂ —), a selenium atom or the like may be contained. Here, the lone electron pair in the nitrogen-containing aromatic ring group (La) having a lone electron pair is not a π electron on the aromatic ring but a lone electron pair not involved in the bond.
This nitrogen-containing aromatic ring group (La) does not have an anionic carbon atom or nitrogen atom as a ring constituent atom bonded to the metal ion M, and does not have an anionic functional group. It is a cyclic group. An anionic carbon atom or nitrogen atom and an anionic functional group will be described later. The ring in the nitrogen-containing aromatic ring group (La) is preferably a 5- to 7-membered ring and may be condensed. Examples of the ring of such a nitrogen-containing aromatic ring group (La) include an anionic carbon atom or nitrogen as a ring-constituting atom bonded to the metal ion M in the nitrogen-containing aromatic heterocycle described in ring A or the like. The thing which does not have an atom is mentioned. Specific examples include an oxazole ring, a thiazole ring, a pyridine ring, a quinoline ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a triazine ring, and a pyrazole ring group in which the atom bonded to the metal ion M is a nitrogen atom at the 2-position. And a pyridine ring is preferred. The nitrogen-containing aromatic ring group (La) may have a substituent T. When the ligand L ² is selected from the nitrogen-containing aromatic ring group (La), the nitrogen-containing aromatic ring group (La) has a substituent T. It is preferable. The substituent T of the nitrogen-containing aromatic ring group (La) is an alkyl group, an alkenyl group, an aryl group, a heterocyclic group, an aryl group substituted with one or two or more alkoxy groups, and one or two or more alkyl groups. An aryl group or heterocyclic group having one, an aryl group having one or more alkyl groups or an alkenyl group substituted with a heterocyclic group is preferred.

When the nitrogen-containing aromatic ring group (Lb) having an anionic nitrogen atom as a ring-constituting atom bonded to the metal ion M is incorporated as a ligand of a metal complex dye, at least one of the nitrogen-containing aromatic ring groups It is a carbocyclic aromatic group in which the nitrogen atom —NH— moiety becomes an anion —N ⁻ —. The nitrogen-containing aromatic ring group (Lb) is preferably one in which the -NH- moiety becomes an anion -N ^-- and can be bonded or bonded to the metal ion M. That is, this nitrogen-containing aromatic ring group (Lb) is a nitrogen-containing aromatic ring group in which the nitrogen atom that is a ring-constituting atom bonded to the metal ion M has active hydrogen. The ring in the nitrogen-containing aromatic ring group (Lb) is preferably a 5- to 7-membered ring and may be condensed. Examples of the ring of the nitrogen-containing aromatic ring group (Lb) include those having an anionic nitrogen atom among the nitrogen-containing aromatic hetero rings described in Ring A and the like. Specifically, imidazole A ring group, a triazole ring group, a benzimidazole ring group, a 1H-indazole ring group, a purine ring group, a pyrrole ring group, a pyrazole ring group in which the atom bonded to the metal ion M is a nitrogen atom at the 1-position, and the like. A cyclic group, a triazole ring group, a pyrrole ring group, and a pyrazole ring group in which the atom bonded to the metal ion M is the nitrogen atom at the 1-position are preferable.

  This nitrogen-containing aromatic ring group (Lb) is represented by the following formulas (a-1) to (a-5) derived from an imidazole ring group, a pyrazole ring group, a triazole ring group, or a pyrrole ring group, among the above-described ones. The group represented by (a-1), (a-2) or (a-5) is more preferred, and the 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. As Rd, the above-mentioned substituent T is mentioned, for example.

  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.

When an aromatic ring group (Lc) other than a nitrogen-containing aromatic ring group (Lb) having an anionic carbon atom as a ring-constituting atom bonded to the metal ion M is incorporated as a ligand of a metal complex dye carbon atoms = CH- moiety of the aromatic ring group anion = C ^- - is an aromatic ring group becomes. As such an aromatic ring group (Lc), any ring having a carbon atom as a ring constituent atom bonded to the metal ion M and exhibiting aromaticity may be used, for example, an aromatic hydrocarbon ring group, Examples of the ring group atom bonded to the heterocyclic group and the metal ion M include a nitrogen-containing aromatic ring group having no nitrogen atom. Examples of the aromatic hydrocarbon ring group include those having an anionic carbon atom as a ring constituent atom among the aryl groups of the substituent T, in particular, m, m-difluorobenzene ring, o, p-difluorobenzene ring, p-fluoro. Examples thereof include a benzene ring, a p-cyanobenzene ring, a p-nitrobenzene ring, a cyclopentadiene ring, a naphthalene ring, and an unsubstituted benzene ring. The substitution positions o, m and p of the benzene ring represent positions with respect to the carbon atom bonded to the metal ion M. Moreover, as the heterocyclic group, among the heterocyclic groups of the substituent T, those in which a carbon atom becomes anionic as a ring constituent atom, for example, furan, thiophene and the like can be mentioned. Furthermore, examples of the nitrogen-containing aromatic ring group in which the ring-constituting atom bonded to the metal ion M is not a nitrogen atom include a pyrazole ring group in which the atom bonded to the metal ion M is a 5-position carbon atom, and an atom bonded to the metal ion M. A pyridine ring group in which is a 4-position carbon atom.

As the aromatic hydrocarbon ring group (Ld) substituted with a functional group having an anionic nitrogen atom, oxygen atom or sulfur atom, the nitrogen atom of the functional group when incorporated as a ligand of a metal complex dye, An aromatic hydrocarbon ring group in which at least one —XH— or —XH moiety (X represents N, O or S) of an oxygen atom or a sulfur atom becomes an anion —X ⁻ — or —X ^— . Then, the aromatic hydrocarbon Hajime Tamaki (Ld), the -XH- or -XH moiety anion -X ^- - or -X ^- bonded to the metal ion M becomes, or it can bond. That is, this aromatic hydrocarbon ring group (Ld) is an aromatic hydrocarbon ring group in which at least one nitrogen atom, oxygen atom or sulfur atom constituting the functional group has active hydrogen. Examples of the ring in the aromatic hydrocarbon ring group (Ld) include a ring composed of the aryl group of the substituent T, and the ring may have the substituent T.

  Examples of the functional group possessed by such an aromatic hydrocarbon ring group (Ld) include a hydroxyl group, a thiol group, an amino group, a substituted amino group, a hydroxyalkyl group, a mercaptoalkyl group, and an aminoalkyl group. , A thiol group, an amino group, and a substituted amino group are preferable. Specific examples of the aromatic hydrocarbon ring group (Ld) having such a functional group include a phenol ring group, a thiophenol ring group, an aniline ring group, a substituted aniline ring group, a hydroxyalkylbenzene ring group, and a mercaptoalkylbenzene ring. Group, anomialkylbenzene ring group and the like.

Among these functional groups, the substituted amino group is an amino group in which one of its hydrogen atoms is substituted, and examples thereof include —NHSO ₂ Ry (Ry represents a substituent). Examples of Ry include the substituent T described above, and an alkyl group is particularly preferable. 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. The hydroxyalkyl group is an alkyl group in which at least one of its hydrogen atoms is substituted with a hydroxyl group, and examples thereof include a hydroxymethyl group and a hydroxyethyl group. The mercaptoalkyl group is an alkyl group in which at least one of its hydrogen atoms is substituted with a thiol group, and examples thereof include a mercaptomethyl group and a mercaptoethyl group. An aminoalkyl group is an alkyl group in which at least one of its hydrogen atoms is substituted with an amino group, and examples thereof include an aminomethyl group and an aminoethyl group. Here, in the hydroxyalkyl group, mercaptoalkyl group and anomialkyl group, the carbon atom of the alkyl group to which the hydroxy group, mercapto group or amino group is bonded is not particularly limited, but considering the ease of coordination with the metal ion M The terminal carbon atom of the alkyl group is preferable.

As the nitrogen-containing aromatic ring group (Le) substituted with a functional group having an anionic nitrogen atom, oxygen atom or sulfur atom, the nitrogen atom of the functional group when incorporated as a ligand of a metal complex dye, at least one -XH- or -XH portion of the oxygen atom or a sulfur atom (X represents N, O or S.) is the anion -X ^- is to become nitrogen-containing aromatic ring group ^- - or -X. Then, the nitrogen-containing aromatic Hajime Tamaki (Le), the -XH- or -XH moiety anion -X ^- - or -X ^- bonded to the metal ion M becomes, or it can bond. That is, this nitrogen-containing aromatic ring group (Le) is a nitrogen-containing aromatic ring group in which at least one nitrogen atom, oxygen atom or sulfur atom constituting the functional group has active hydrogen. This nitrogen-containing aromatic ring group (Le) is synonymous with the aromatic hydrocarbon ring group (Ld) except that it has a nitrogen-containing aromatic ring group instead of the aromatic hydrocarbon ring group. That is, the functional group of the nitrogen-containing aromatic ring group (Le) is synonymous with the functional group of the aromatic hydrocarbon ring group (Ld), and preferred ones are also the same. The nitrogen-containing aromatic ring group of the nitrogen-containing aromatic ring group (Le) may be the same ring as the ring of the nitrogen-containing aromatic ring group (La) or the ring of the nitrogen-containing aromatic ring group (Lb). A ring similar to the ring of the nitrogen-containing aromatic ring group (La) having no active hydrogen is preferable. This nitrogen-containing aromatic ring group (Le) may have a substituent T, for example.

  The ligand (Lf) may be any ligand other than (La) to (Le), for example, an inorganic ligand, or a nitrogen-containing aromatic ring group or ligand (Ld) and (Le And an organic ligand having no functional group. In the present invention, an inorganic compound or an anion, atom or compound derived from the inorganic compound is referred to as an inorganic ligand, and the organic compound or the organic compound bonded to the metal ion M other than the nitrogen-containing aromatic ring group or this functional group The derived anion is called an organic ligand. Examples of such ligands include known ligands without any particular limitation. For example, acyloxy anion, acylthioanion, thioacyloxyanion, thioacylthioanion, acylaminooxyanion, thiol Carbamate anion, dithiocarbamate anion, thiocarbonate anion, dithiocarbonate anion, trithiocarbonate anion, acyl anion, thiocyanate anion, isothiocyanate anion, cyanate anion, isocyanate anion, cyano anion, alkylthio anion, alkoxy anion An anion selected from or a monodentate ligand bonded by these groups, or a halogen atom, cyano, ether, thioether, sulfoxide, carbonyl, Alkyl ketones, carboxylic amides, represents a monodentate ligand selected from the group of anions consisting of thio carboxylic amides and thioureas, atom or compound (including a compound anion hydrogen atoms are substituted). In addition, when this ligand (Lf) contains an alkyl group, an alkenyl group, an alkynyl group, an alkylene group, etc., these may be linear, branched or cyclic, and may be substituted or unsubstituted. Moreover, when a ligand (Lf) contains an aryl group, a heterocyclic group, a cycloalkyl group, etc., they may be substituted or unsubstituted, and may be monocyclic or condensed.

  In the present invention, the ligand (Lf) is preferably an anion such as a cyanate anion, an isocyanate anion, a thiocyanate anion, and an isothiocyanate anion, more preferably an isocyanate anion and an isothiocyanate anion, and particularly preferably an isothiocyanate anion. .

The ligands L ¹ , L ² and L ³ are each selected from the group consisting of (La) to (Lf), and one or two of them have as an anionic coordination atom, for example, ( Lb) to (Le) and (Lf) are selected from the group consisting of anions, and the remaining two or one is selected from (La) and optionally (Lf). At this time, the ligands L ¹ and L ² are directly bonded to form a bidentate ligand, and the ligands L ¹ , L ² and L ³ are directly bonded to form a tridentate ligand. Form. In particular, when L ¹ and L ² are bonded to each other in terms of increasing photoelectric conversion efficiency of the photoelectric conversion element, the ligand L ² is selected from (La) and coordinated. The child L ¹ is preferably an anionic ligand with a coordination atom selected from (Lb) to (Le), and the ligand L ³ is selected from the ligand (Lf). Is particularly preferred. In addition, when L ¹ , L ² and L ³ are tridentate ligands bonded to each other in terms of increasing the photoelectric conversion efficiency of the photoelectric conversion element, the ligand L ² is selected from (La). In the ligands L ¹ and L ^{3, the} coordination atom selected from the above (Lb) to (Le) is preferably an anionic ligand.

The bidentate ligand in which L ¹ and L ² are bonded to each other is preferably a bidentate ligand represented by any of the following formulas (2L-1) to (2L-5).

In the formulas (2L-1) to (2L-5), * represents a bonding position to the metal ion M. Ring D represents an aromatic ring. A ^{111 to} A ^{141 each} represents an anionic nitrogen atom or carbon atom, and A ¹⁵¹ represents any one of an anionic nitrogen atom, oxygen atom or sulfur atom. R ^{111 to} R ^{154 each} represent a hydrogen atom or a substituent that does not have Anc1, Anc2, and Anc3.

A ^{111 to} A ¹⁴¹ are a carbon anion or a nitrogen anion from which a hydrogen atom bonded to a nitrogen atom or a carbon atom constituting the ring D is eliminated. A ¹⁵¹ is synonymous with a residue obtained by removing active hydrogen from a (substituted) amino group, hydroxyl group or thiol group among the functional groups in the aromatic hydrocarbon ring group (Ld) and the nitrogen-containing aromatic ring group (Le). In the formulas (2L-1) to (2L-5), examples of the ring D include aromatic carbocycles, oxygen-containing aromatic heterocycles, sulfur-containing aromatic heterocycles, and nitrogen-containing aromatic heterocycles. This aromatic ring is, for example, a nitrogen-containing aromatic ring composed of a nitrogen-containing aromatic ring group (Lb) or an aromatic hydrocarbon ring composed of an aromatic hydrocarbon ring group of (Lc), ( A heterocyclic ring composed of a heterocyclic group of Lc), or a nitrogen-containing aromatic ring composed of a nitrogen-containing aromatic ring group having no nitrogen atom as a ring-constituting atom bonded to the metal ion M of (Lc) Etc., and preferable examples are also the same. In Formulas (2L-1) to (2L-4), Ring D before A ^{111 to} A ¹⁴¹ are anionized and Ring D substituted by A ¹⁵¹ in Formula (2L-5) are, for example, a benzene ring, m, m-difluorobenzene ring, o, p-difluorobenzene ring, p-fluorobenzene ring, p-cyanobenzene ring, p-nitrobenzene ring or thiophene ring, furan ring, or formulas (a-1) to (a-5) ), (A-1a), (a-2a), (a-1b) and a ring in which the anion portion of the group represented by (a-4a) is substituted with a hydrogen atom.

Examples of the substituent of R ^{111 to} R ¹⁵⁴ include a substituent T, among which a heterocyclic group, an aromatic carbocyclic group, an ethenyl group, an ethynyl group, a halogen atom, an alkyl group, an amino group (an alkylamino group, A dialkylamino group, an arylamino group, a diarylamino group, an N-alkyl-arylamino group, etc.), an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, and a silyl group are preferred, a heterocyclic group, an aromatic carbocycle Group, ethenyl group, alkyl group and amino group (including alkylamino group, dialkylamino group, arylamino group, diarylamino group, N-alkyl-arylamino group and the like) are more preferable.
When two of the ligands L ^{1 to} L ³ are bidentate ligands, the remaining ligand is a ligand in which at least one of the ligands L ^{1 to} L ³ has an anionic coordination atom. It is preferably selected from (La) to (Lf) so as not to be a ligand, and an NCS (isothiocyanate) ligand is selected.

As the tridentate ligand in which L ¹ , L ² and L ³ are bonded to each other, a tridentate ligand represented by any of the following formulas (3L-1) to (3L-5) is preferable.

In the formulas (3L-1) to (3L-5), * represents a bonding position to the metal ion M. Ring D represents an aromatic ring. A ^{211 to} A ²⁴² represent a nitrogen atom or a carbon atom, and A ²⁵¹ and A ²⁵² represent a nitrogen atom, an oxygen atom, or a sulfur atom. However, at least one of A ²¹¹ and A ²¹² , A ²²¹ and A ²²² , A ²³¹ and A ²³² , A ²⁴¹ and A ²⁴² , and A ²⁵¹ and A ²⁵² is anionic. R ^{211 to} R ²⁵³ represent a hydrogen atom or a substituent that does not have Anc 1, Anc 2, and Anc 3.

What is anionic among A ^{211 to} A ^{242 has} the same meaning as A ^{111 to} A ^{141 in} formulas (2L-1) to (2L-5). Among A ^{211 to} A ²⁴² , those having no anionic property are carbon atoms or nitrogen atoms not having a hydrogen atom. A ²⁵¹ and A ²⁵² have the same meaning as A ^{151 in the} formula (2L-5). Ring D in the formulas (3L-1) to (3L-5) has the same meaning as the ring D in the formulas (2L-1) to (2L-5), and specifically, any one of A ^{211 to} A ²⁴² An aromatic hydrocarbon ring or a nitrogen-containing aromatic ring composed of an aromatic hydrocarbon ring group or a nitrogen-containing aromatic ring group containing one and two carbon atoms or two carbon atoms. At this time, in each formula, two rings D may be the same or different. The substituents R ^{211 to} R ²⁵³ are the same as the substituents R ^{111 to} R ¹⁵⁴ in the formulas (2L-1) to (2L-5), and preferred ones are also the same.

− Counter ion Y −
Y in the formula (I) represents a charge neutralizing counter ion when a counter ion is required 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 represented by the formula (I) may be dissociated and have a negative charge because the substituent has a dissociable group. In this case, the charge of the whole metal complex dye represented by the formula (I) 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, pyridinium ion, etc.), phosphonium ion (for example, tetraalkylphosphonium ion, alkyltriphenylphosphonium ion). Etc.), alkali metal ions or protons.

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, halogen anions (eg, fluoride ions, chloride ions, bromide ions, iodide ions, etc.), substituted aryl sulfonate ions (eg, p-toluene sulfonate ions, p-chlorobenzene sulfonate ions, etc.), aryl disulfones Acid ion (for example, 1,3-benzenedisulfonic acid ion, 1,5-naphthalenedisulfonic acid ion, 2,6-naphthalenedisulfonic acid ion, etc.), alkyl sulfate ion (for example, methyl sulfate ion, etc.), sulfate ion, thiocyanate ion Perchlorate ion, tetrafluoroborate ion, hexafluorophosphate ion, picrate ion, acetate ion, trifluoromethanesulfonate 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.
In the present invention, Y is preferably an inorganic or organic ammonium ion, particularly tetrabutylammonium ion, sodium ion or proton.

− N −
The counter ion Y should just be a number required in order to neutralize an electric charge, and is normally selected from the integers of 0-2.

Specific examples of the metal complex dye of the present invention are shown below, but the present invention is not limited thereto.
Here, Me in the following specific examples represents methyl, and TMS represents trimethylsilyl.

  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 dyes of the present invention are disclosed in JP-A No. 2001-291534 and a method according to the method cited in the publication, Chem. Commun. , 2009, 5844-5846, Angew. Chem. Int. Ed. , 50, 2054-2058 (2011), or a method analogous thereto.

  An example is briefly described. First, as a starting material, using a nitrogen-containing aromatic heterocyclic compound having a halogen atom at the 2-position and having a halogen atom, an aldehyde group or an acetal group directly or via a substituent at a position where an acidic group is introduced, A precursor represented by the formula (IIA) is synthesized. This precursor is a precursor of a tridentate acceptor ligand composed of ring A to ring C having at least an aldehyde group or an acetal group in ring A.

Where
Ring A, ring B and ring C each independently represent a nitrogen-containing aromatic heterocycle. Z ¹ and Z ² each independently represent a carbon atom or a nitrogen atom. Here, the bond between Z ¹ and the N atom and the bond between Z ² and the N atom may be a single bond or a double bond.
R ^{1 to} R ³ each independently represents a substituent. n1 and n3 each independently represents an integer of 0 to 4, and n2 represents an integer of 0 to 3. When a plurality of R ^{1 to} R ³ are present in each of them, they may be bonded to each other to form a ring.
X ¹⁰ and X ³⁰ each independently represent a single bond or a linking group. X ²⁰ represents a single bond or —O—, —S—, —NR ′ (R ′ represents a hydrogen atom or a substituent) —, a saturated aliphatic group, an unsaturated group that does not π-conjugated with the ring B. A saturated aliphatic group, a non-aromatic hydrocarbon ring group, a non-aromatic heterocyclic group, or a combination thereof is represented.
G represents an acetal group which may have an aldehyde group or a substituent.
p1 represents an integer of 1 to 4, p2 represents an integer of 0 to 3, and p3 represents an integer of 0 to 4, respectively.

Ring A, ring B and ring C are the same as ring A, ring B and ring C in formula (I), respectively, and preferred ranges are also the same. Z ¹ and ^{Z 2} has the same meaning as ^{Z 1} and ^{Z 2} in each formula (I).
R < ¹ > -R < ³ > is synonymous with R < ¹ > -R < ³ > in Formula (I), respectively, and its preferable range is also the same. n1-n3 is synonymous with n1-n3 in Formula (I), respectively, and its preferable range is also the same.
X ¹⁰ is synonymous with X ¹ in formula (I) except that it contains a single bond, and the preferred range is also the same, and particularly preferably an aromatic hydrocarbon ring group, an aromatic heterocyclic group or a single bond. X ²⁰ is synonymous with X ² in formula (I) except that it contains a single bond, and the preferred range is also the same, and particularly preferably a single bond. X ³⁰ has the same meaning as X ³ in formula (I), and the preferred range is also the same, and particularly preferably an aromatic hydrocarbon ring group, an aromatic heterocyclic group or a single bond.

  G represents an aldehyde group or an acetal group which is represented by any one of the following structures and may have a substituent.

In formula, R ^<G > represents an alkyl group each independently. * Represents a bonding position with X ¹⁰ , X ²⁰ or X ³⁰ .
R ^G each independently represents an alkyl group, preferably an alkyl group having 1 to 8 carbon atoms, and particularly preferably an alkyl group having 1 or 2 carbon atoms. Examples of the alkyl group having 1 to 8 carbon atoms include methyl, ethyl, propyl, butyl, hexyl, octyl and the like.
The substituent T may be mentioned as the substituent that the acetal group may have.

  p1 to p3 are respectively synonymous with m1 to m3 in formula (I), and preferred ones are also the same.

This precursor is coordinated to a compound of metal ion M, and if desired, a bidentate ligand in which L ¹ and L ² are separately bonded or a tridentate in which L ¹ , L ² and L ³ are bonded to each other A ligand is coordinated to the metal ion M to synthesize a metal complex represented by the following formula (II) as a synthetic intermediate.

In the formula, ring A to ring C, Z ¹ , Z ² , R ^{1 to} R ³ , n1 to n3, X ^{10 to} X ³⁰ , G, p1 to p3, Y, and n are as defined in formula (IIA). M represents a metal ion.
L ^{1 to} L ³ each represent a ligand, each of which is a monodentate ligand, a bidentate ligand in which L ¹ and L ² are bonded to each other, or L ¹ , L ² and L ³ are bonded to each other It is a tridentate ligand. Here, one or two of L ^{1 to} L ³ represents a ligand having an anionic coordination atom.
Y represents a counter ion necessary for neutralizing the charge, and n represents an integer of 0 to 2.

Any one of L ^{1 to} L ³ in the formula (II) may be a monodentate ligand as long as one or two of them have an anionic coordination atom. The metal complex in which L ^{1 to} L ³ are all monodentate ligands can be obtained by coordinating the precursor represented by the formula (IIA) to the compound of the metal ion M. In this metal complex, L ^{1 to} L ³ which are monodentate ligands are synonymous with the ligands (La) to (Lf) in the formula (I), and the availability or preparation of the compound of the metal ion M From the viewpoint of ease, the ligand (Lf) is preferable among the ligands (La) to (Lf) in the formula (I), and an inorganic compound or an anion derived from an inorganic compound is more preferable, and a chlorine anion (Cl ^- is preferably a) ^-) and isothiocyanate anion (NCS. The compound of the metal ion M is not particularly limited, and examples thereof include a halide of the metal ion M.

The metal complex which is a bidentate ligand in which L ¹ and L ² are bonded to each other among L ^{1 to} L ³ in the formula (II) is used as a compound of the metal ion M as a precursor represented by the formula (IIA). It can be obtained by coordinating the metal ion M with a bidentate ligand in which L ¹ and L ² synthesized separately after coordination are bonded to each other. In the metal complexes, bidentate ligands L ¹ and L ² are bonded to each other has the same meaning as ligand bidentate where L ¹ and L ² in formula (I) bonded to each other, preferably those same It is. The ligand L ³ is selected from the ligands (La) to (Lf), and is preferably selected from the ligand (Lf).

Wherein the metal complex ^L 1, ^{L 2} and ^{L 3} are tridentate ligands bonded to each other among the ^L 1 ~L ³ in (II) has the formula metal precursor represented by (IIA) ion M It is obtained by coordinating the metal ion M with a tridentate ligand in which L ¹ , L ² and L ³ which are separately synthesized are coordinated with each other, and then synthesized. In the metal ^complexes, L 1, ^{L 2} and ^{L 3} are tridentate ligand bound to each other, tridentate ligands synonymous the ^L 1, ^{L 2} and ^{L 3} in formula (I) bonded to each other The preferred ones are also the same.
Metal ion M has the same meaning as M in formula (I), and preferred ones are also the same.

Next, this metal complex can be reacted with compounds corresponding to the linking groups X ^{1 to} X ³ and the acidic groups Anc ^{1 to} Anc ³ to synthesize the metal complex dye represented by the formula (I). For example, when the portion to which the acidic group Anc is bonded in the linking group is an ethenylene group (including the linking linking group), an active methylene compound such as cyanoacetic acid and the metal complex represented by the formula (II) Is subjected to, for example, a Knoevenagel condensation reaction to synthesize a metal complex dye represented by the formula (I). Here, when G of the metal complex represented by the formula (II) is an acetal group, it is preferably deprotected by hydrolysis or the like to be an aldehyde group.

− 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. Examples of the plastic support include a transparent polymer film described in paragraph No. 0153 of JP-A No. 2001-291534. 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 conductive support, the surface may have 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. And may have a light guide function described in JP-A-2002-260746.

  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.

  In order to prevent reverse current due to direct contact between the electrolyte and the electrode, 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 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, 1-50 micrometers is preferable and 3-30 micrometers is more preferable. 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 60 to 400 ° 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.

  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 Ru complex dyes described in JP-A-7-500630 (especially dyes synthesized in Examples 1 to 19 on page 5, lower left column, line 5 to page 7, upper right column, line 7). ), Ru complex dyes described in JP-T-2002-512729 (especially dyes synthesized in Examples 1 to 16 on the third line to the 29th page and the 23rd line from the bottom of page 20), JP-A-2001- Ru complex dyes described in Japanese Patent No. 59062 (especially dyes described in paragraphs 0087 to 0104), Ru complex dyes described in Japanese Patent Application Laid-Open No. 2001-6760 (particularly dyes described in paragraphs 0093 to 0102), Ru complex dyes described in JP-A No. 2001-253894 (particularly dyes described in paragraph Nos. 0009 to 0010), Ru complex dyes described in JP-A No. 2003-212851 (particularly colors described in paragraph No. 0005) ), Ru complex dyes described in International Publication No. 2007/91525 pamphlet (particularly the dye described in [0067]), Ru complex dyes described in Japanese Patent Application Laid-Open No. 2001-291534 (particularly in paragraphs 0120 to 0144). Described), Ru complex dyes described in JP2012-012570A (especially, dyes described in paragraphs 0095 to 0103), squarylium cyanine dyes described in JP11-214730A (particularly, paragraph numbers) Dyes described in JP-A-2012-144688, squarylium cyanine dyes described in JP2012-144688 (particularly, dyes described in paragraphs 0039 to 0046 and paragraphs 0054 to 0060), JP2012-84503A. The squarylium cyanine dyes described (particularly paragraphs 0066-0076) The organic dyes described in JP-A-2004-063274 (particularly the dyes described in paragraph Nos. 0017 to 0021), and the organic dyes described in JP-A-2005-123033 (particularly paragraph numbers). 0021 to 0028), organic dyes described in JP-A-2007-287694 (particularly dyes described in paragraphs 0091 to 0096), organic dyes described in JP-A-2008-71648 (particularly, Paragraph Nos. 0030 to 0034), organic dyes described in WO 2007/119525 pamphlet (particularly, the dye described in [0024]), 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). The charge transfer layer includes an electrolyte. Examples of the electrolyte include a liquid electrolyte obtained by dissolving a redox couple in an organic solvent, a so-called gel electrolyte obtained by impregnating a polymer matrix obtained by dissolving a redox couple in an organic solvent, and a molten salt containing the redox couple. . In order to increase the photoelectric conversion efficiency, a liquid electrolyte is preferable. As the solvent for the liquid electrolyte, a nitrile compound, an ether compound, an ester compound or the like is used, and a nitrile compound is preferable, and acetonitrile and methoxypropionitrile are particularly preferable.

  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 trivalent iron complexes (for example, red blood salt and yellow blood salt), 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 CI in the formula (I).
LL is preferably a ligand represented by the following formula (LC).

In the formula (LC), X ^LC1 and X ^LC3 each independently represent a carbon atom or a nitrogen atom. Here, when X ^LC1 is a carbon atom, the bond between X ^LC1 and N atom represents a double bond (X ^LC1 = N), and when X ^LC3 is a carbon atom, the bond between X ^LC3 and N atom is a double bond. ( ^XLC3 = N), when ^XLC1 is a nitrogen atom, the bond between ^XLC1 and N atom represents a single bond ( ^XLC1- N), and when ^XLC3 is a nitrogen atom, ^XLC3 and N atom The bond represents a single bond ( ^XLC3- N).
Z ^LC1 , Z ^LC2 and Z ^LC3 each independently represent a nonmetallic atom group necessary for forming a 5-membered ring or a 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. q represents 0 or 1; Examples of the substituent include the substituent T described later. In addition, when q is 0, the carbon atom at the position where X ^LC3 is bonded to the 5-membered ring or 6-membered ring formed by Z ^LC2 is a hydrogen atom or a substituent other than the heterocyclic group formed by Z ^LC3 Join.

  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-4).

R ^{LC1 to} R ^LC11 each independently represent a substituent. q1, q2, q6 and q7 each independently represents an integer of 0 to 4. q3, q5, q10 and q11 each independently represents an integer of 0 to 3. q4 represents an integer of 0 to 2.

In the formulas (LC-1) to (LC-4), ^examples of the substituent represented by R ^{LC1 to} R ^LC11 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 having a ligand 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.

  Moreover, in order to improve photoelectric conversion efficiency, you may take the method of controlling the water | moisture content of electrolyte solution. 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, or 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 Inclusion of polymers, liquid crystal compounds, ether-bonded polymers, polyvinylidene fluoride, methacrylate / acrylate, thermosetting resins, crosslinked polysiloxane, polyvinyl alcohol (PVA), polyalkylene glycol and dextrin Examples thereof include compounds, systems to which oxygen-containing or sulfur-containing polymers are added, natural polymers, and the like. 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, and the like may be added thereto.

  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 a bifunctional or higher 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-like 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, an aromatic such as triarylamine Examples include amine derivatives, triphenylene derivatives, nitrogen-containing heterocyclic derivatives, and liquid crystalline cyano derivatives.

  Since the redox couple becomes an electron carrier, a certain concentration is required. A preferable concentration is 0.01 mol / L or more in total, more preferably 0.1 mol / L or more, and particularly preferably 0.3 mol / L or more. The upper limit in this case is not particularly limited, but is usually about 5 mol / L.

− 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 coadsorbent, a coadsorbent having at least one acidic group (preferably a carboxyl group or a salt group thereof) is preferable, and examples thereof include compounds 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, and its preferable range is also the same.
Among these, R ^A1 is preferably a carboxyl group or an alkyl group substituted by a sulfo group or a salt thereof, —CH (CH ₃ ) CH ₂ CH ₂ CO ₂ H, —CH (CH ₃ ) CH ₂ CH ₂ CONHCH. More preferred is ₂ CH ₂ SO ₃ H.

Examples of R ^A2 include the substituent T described later. Among them, an alkyl group, a hydroxy group, an acyloxy group, an alkylaminocarbonyloxy group, and an arylaminocarbonyloxy group are preferable, and an alkyl group, a hydroxy group, and an acyloxy group are more preferable. .
nA is preferably from 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.

<Counter electrode (counter electrode)>
The counter electrode is preferably a positive electrode of 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 photoreceptor layer, at least one of the conductive support and the counter electrode described above 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 a 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 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, Dye-Adsorbing Electrode and Dye-Sensitized Solar Cell Manufacturing Method Using It >>
In this invention, it is preferable to manufacture a pigment | dye adsorption electrode using the pigment | dye solution containing the metal complex pigment | dye of this 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. As the mixed solvent, a mixed solvent of an alcohol and a solvent selected from amides, nitriles or hydrocarbons is preferable. 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 producing a photoelectric conversion element or a dye-sensitized solar cell. . In this invention, it is preferable to contain the metal complex pigment | dye of this invention 0.001-0.1 mass%.

In the dye solution, it is particularly preferable to adjust the water content. Therefore, in the present invention, the water content (content ratio) is preferably adjusted to 0 to 0.1% by mass.
Similarly, the adjustment of the water content of the electrolyte in the photoelectric conversion element or the dye-sensitized solar cell is also preferable in order to effectively exhibit the effect of the present invention. For this reason, the water content (content rate) of the electrolyte solution is It is preferable to adjust to 0-0.1 mass%. The electrolyte is particularly preferably adjusted with a dye solution.

In the present invention, a dye adsorption electrode which is a semiconductor electrode for a dye-sensitized solar cell in which a metal complex dye is supported on the surface of a semiconductor fine particle provided in a semiconductor electrode using the dye solution is preferable.
That is, a dye-adsorbing electrode for a dye-sensitized solar cell is obtained by applying a composition obtained from the dye solution onto a conductive support provided with semiconductor fine particles, and curing the composition after application. What was made into the photoreceptor layer is preferable.
In the present invention, it is preferable to produce a dye-sensitized solar cell by using the dye-adsorbing electrode for the dye-sensitized solar cell, preparing an electrolyte and a counter electrode, and assembling them using these.

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

<Synthesis of metal complex dye>
Hereinafter, the method for synthesizing the metal complex dye of the present invention will be described in detail, but the starting material, the dye intermediate and the synthesis route are not limited thereto.

  [Metal Complex Dye Dye-1] to [Metal Complex Dye Dye-9] were synthesized as follows.

Example 1 [Synthesis of Metal Complex Dye]
[Synthesis of Metal Complex Dye-1]
A synthesis scheme of the metal complex dye Dye-1 is shown below.

(I) Synthesis of Compound (2) 11.6 g of Compound (1), 7 mL of ethylene glycol, 3.56 g of p-toluenesulfonic acid monohydrate, and 58 mL of dehydrated toluene were placed in a 200 mL three-necked flask and stirred. Molecular sieves 4A was added to the obtained solution, and the mixture was heated to reflux for 3 hours. The temperature was returned to room temperature, an aqueous sodium hydrogen carbonate solution was added, the mixture was stirred, adjusted to pH 8, and extracted with ethyl acetate. The organic layer was filtered to remove insolubles, concentrated under reduced pressure, and purified by silica gel column chromatography to obtain 13.31 g of compound (2). The obtained compound (2) was identified by ¹ H-NMR.

(Ii) Synthesis of Compound (4) 11.7 g of Compound (2), 20 g of {(CH ₃ ) ₃ Sn} ₂ , 203 mL of dehydrated toluene, and 5.88 g of tetrakistriphenylphosphine palladium were placed in a 500 mL three-necked flask. The mixture was heated to reflux for 3 hours under a nitrogen atmosphere to produce compound (3). Thereafter, 5.42 g of 2,6-dibromopyridine and 5.88 g of tetrakistriphenylphosphine palladium were added, and the mixture was further heated to reflux for 1 hour. It returned to room temperature, chloroform was added, and the ultrasonic treatment was performed, Then, the insoluble matter was removed by filtration. The solvent was distilled off under reduced pressure, methanol was added and sonication was performed, and the precipitate was separated by filtration. The filtrate was concentrated under reduced pressure and purified by alumina column chromatography. The obtained crude crystals were completely dissolved in dichloromethane, hexane was added, and dichloromethane was distilled off using an evaporator. The produced precipitate was filtered and washed with hexane to obtain 2.48 g of Compound (4). This compound (4) is a precursor of an acceptor ligand represented by the formula (IIA). The obtained compound (4) was identified by ¹ H-NMR.

(Iii) Synthesis of Compound (5) 500 mg of compound (4), ruthenium chloride and ethanol were placed in a 200 mL three-necked flask and heated to reflux for 6 hours under a nitrogen atmosphere. The obtained precipitate was filtered and washed with ethanol to obtain 540 mg of Compound (5). This compound (5) is a metal complex represented by the formula (II), wherein L ^{1 to} L ³ are all monodentate ligands. The resulting compound (5) was identified by ESI-MS. A fragment from which two Cls were eliminated was detected. ESI-MS: [M-Cl ₂ ] ⁺ = 513.8

(Iv) Synthesis of Compound (6) 280 mg of Compound (5), 296 mg of Compound (5 ′) separately synthesized in the same manner as Compound (4), 264 mg of N-methylmorpholine, 3 mL of dehydrated N, N-dimethylformamide in 10 mL The mixture was placed in an eggplant flask and reacted at an external temperature of 150 ° C. for 2 hours. The temperature was returned to room temperature, ethyl acetate and 1N hydrochloric acid were added to carry out a liquid separation operation, and the organic layer was concentrated under reduced pressure. After purification by alumina column chromatography using ethyl acetate as an eluent, the ethyl acetate was concentrated under reduced pressure, and hexane was added to form a precipitate. This was filtered and washed with hexane to obtain 192 mg of Compound (6). This compound (6) is a tridentate ligand in which L ¹ , L ² and L ³ are bonded to each other, and G is an acetal group and is a metal complex represented by the formula (II). The obtained compound (6) was identified by ¹ H-NMR and ESI-MS.

[Compound (6)]
ESI-MS: [M + H] ⁺ = 1157.4
¹ H-NMR: A chart of ¹ H-NMR spectrum (measuring solvent; CDCl ₃ ) is shown in FIG.

(V) Synthesis of Compound (7) 175 mg of Compound (6), 1.44 g of p-toluenesulfonic acid monohydrate, 31.5 mL of tetrahydrofuran, and 3.5 mL of distilled water were placed in a 100 mL three-necked flask, and a nitrogen atmosphere The mixture was heated to reflux for 4 hours. Thereafter, 1.44 g of p-toluenesulfonic acid monohydrate was added, and the mixture was heated to reflux for 2 hours. The mixture was returned to room temperature, adjusted to pH 8 with an aqueous sodium hydrogen carbonate solution, and extracted with ethyl acetate. The organic layer was dried under reduced pressure, and sonication was performed by adding hexane. The precipitate was filtered and washed with hexane to obtain 130 mg of compound (7). This compound (7) is a tridentate ligand in which L ¹ , L ^2, and L ³ are bonded to each other, and G is a metal complex represented by the formula (II), in which G is an aldehyde group. The obtained compound (7) was identified by ¹ H-NMR.

[Compound (7)]
¹ H-NMR: A chart of ¹ H-NMR spectrum (measuring solvent; CDCl ₃ ) is shown in FIG.

(Vi) Synthesis of Metal Complex Dye Dye-1 Compound (7) 100 mg, cyanoacetic acid 24 mg, and acetonitrile 3 mL were placed in a 10 mL eggplant flask, and 10 mg of piperidine were added with stirring under a nitrogen atmosphere, and the mixture was heated to reflux. The mixture was returned to room temperature, neutralized with ammonium chloride, and extracted with ethyl acetate. Concentration was performed under reduced pressure, and hexane was added to form a precipitate. Dye-1 was synthesized by filtering the precipitate and washing with hexane. The compound was identified by ¹ H-NMR and ESI-MS.

(Dye-1)
ESI-MS: [M + H] ⁺ = 1203
¹ H-NMR: Chart of ¹ H-NMR spectrum (measuring solvent; DMSO-d6) is shown in FIG.

[Synthesis of Metal Complex Dye-2]
A synthesis scheme of the metal complex dye Dye-2 is shown below in the same manner as in the metal complex dye Dye-1.
The obtained compounds (11) and (12) were identified by ¹ H-NMR. The metal complex dye Dye-2 was identified by ¹ H-NMR and ESI-MS.

[Compound (11)]
¹ H-NMR: A chart of ¹ H-NMR spectrum (measuring solvent; DMSO-d6) is shown in FIG.

[Compound (12)]
¹ H-NMR: A chart of ¹ H-NMR spectrum (measuring solvent; DMSO-d6) is shown in FIG.

(Dye-2)
ESI-MS: [M + H] ⁺ = 1108.6
¹ H-NMR: A chart of ¹ H-NMR spectrum (measuring solvent; DMSO-d6) is shown in FIG.

[Synthesis of Metal Complex Dye Dye-3 and 6]
In the same manner as the metal complex dye Dye-1, metal complex dye Dye-3 and metal complex dye Dye-6 were synthesized.

[Synthesis of Metal Complex Dye-4]
Metal complex dye Dye-4 was synthesized by the following synthesis scheme.

(I) Synthesis of Compound (8) 100 mg of the compound (7) synthesized above, 57.2 μL of methyl diethylphosphonoacetate and 88 mg of potassium carbonate were heated to reflux in THF for 30 minutes, allowed to cool, and then mixed with water and chloride. Separated with methylene. The organic layer was concentrated and purified by silica gel column chromatography to obtain 70 mg of compound (8).

(Ii) Synthesis of metal complex dye Dye-4 After 65 mg of compound (8) was stirred in 1 mL of 1N aqueous sodium hydroxide solution, 2 mL of methanol, and 2 mL of THF for 1 hour, a methanol solution of trifluoromethanesulfonic acid was added dropwise and filtered. As a residue, 50 mg of Dye-4 was obtained.

(Dye-4)
ESI-MS: [M + H] ⁺ = 1153.6
¹ H-NMR: A chart of ¹ H-NMR spectrum (measuring solvent; DMSO-d6) is shown in FIG.

[Synthesis of Metal Complex Dye Dye-5]
A metal complex dye Dye-5 was synthesized according to the following synthesis scheme.
First, the following compound (25) was synthesized according to the following synthesis scheme.

(I) Synthesis of Compound (21) 25 g of Compound (20) (2-acetyl 4-methylpyridine) was dissolved in 200 ml of tetrahydrofuran (THF) and stirred at 0 ° C. in a nitrogen atmosphere while sodium ethoxide 18. 9 g was added and stirred for 15 minutes. Thereafter, 28.9 g of ethyl trifluoroacetate was added dropwise, and the mixture was stirred at an external temperature of 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 72.6 g of a crude product of compound (21).

(Ii) Synthesis of Compound (22) 72.6 g of Compound (21) was dissolved in 220 ml of ethanol, and 5.6 ml of hydrazine monohydrate was added with stirring at room temperature under a nitrogen atmosphere at an external temperature of 90 ° C. Heated for 12 hours. Thereafter, 5 ml of concentrated hydrochloric acid was added and stirred for 1 hour. After concentration, the mixture was extracted and separated with 150 ml of sodium bicarbonate water and 150 ml of ethyl acetate, and the organic layer was concentrated. After recrystallization from acetonitrile, 31.5 g of Compound (22) was obtained.

(Iii) Synthesis of Compound (23) 23.1 ml of 1.6M n-butyllithium hexane solution was added dropwise while stirring 4.1 g of diisopropylamine and 30 ml of tetrahydrofuran at −40 ° C. in a nitrogen atmosphere, followed by stirring for 2 hours. did. Thereafter, 4.0 g of compound (22) was added and stirred at 0 ° C. for 80 minutes, and then a solution of 5.00 g of 2-hexylthiophene-5-carboxaldehyde dissolved in 15 ml of tetrahydrofuran was added dropwise. Then, it stirred at 0 degreeC for 80 minutes, and stirred at room temperature for 5 hours. Thereafter, an ammonium chloride solution was added, and the mixture was extracted and separated with ethyl acetate. The organic layer was concentrated and purified by silica gel column chromatography to obtain 5.0 g of compound (23).

(Iv) Synthesis of Compound (24) 4.9 g of Compound (23) and 4.1 g of PPTS (pyridinium paratoluenesulfonic acid) were added to 50 ml of toluene, and the mixture was heated to reflux for 5 hours in a nitrogen atmosphere. After concentration, liquid separation was performed with saturated aqueous sodium hydrogen carbonate and methylene chloride, and the organic layer was concentrated. The obtained crystals were recrystallized from methanol and methylene chloride to obtain 3.2 g of compound (24).

(V) Synthesis of Compound (25) 1.22 g of dichloro (p-cymene) ruthenium (II) dimer and 1.62 g of compound (24) were added to 150 ml of ethanol and stirred at 70 ° C. for 3 hours in a nitrogen atmosphere. Then, it returned to room temperature, the sodium hydrogen carbonate solution and ethyl acetate were added, liquid separation operation was performed, and the organic layer was concentrate | evaporated under reduced pressure. Acetonitrile was added to the resulting crude product for recrystallization, and filtration and drying were performed to obtain 1.5 g of Compound (25).

  Using the synthesized compound (25) and the compound (27) obtained from the compound (4), a metal complex dye Dye-5 was synthesized by the following synthesis scheme.

(Vi) Synthesis of Compound (27) Compound (26) was synthesized using compound (4) in the same manner as compound (7) was synthesized from compound (6). Subsequently, the compound (27) was synthesized in the same manner as the method of synthesizing the compound (8) from the compound (7).

(Vii) Synthesis of Compound (28) 640 mg of Compound (25), 407 mg of Compound (27), and 10 ml of N, N-dimethylformamide were placed in a three-necked flask and stirred with heating at 130 ° C. for 3 hours. After returning to room temperature, saturated brine and ethyl acetate were added, and liquid separation operation was performed. Then, the organic layer was concentrated under reduced pressure and purified by silica gel column chromatography to obtain 250 mg of compound (28).

(Viii) Synthesis of Compound (29) 182 mg of Compound (28), 142 mg of ammonium thiocyanate, and 4 ml of N, N-dimethylformamide were placed in a three-necked flask and heated and stirred at 130 ° C. for 2 hours. After returning to room temperature, saturated brine and ethyl acetate were added, and liquid separation operation was performed. Then, the organic layer was concentrated under reduced pressure and purified by silica gel column chromatography to obtain 100 mg of compound (29).

(Ix) Synthesis of Metal Complex Dye Dye-5 Compound (29) 88 mg and N, N-dimethylformamide 6 ml were placed in a three-necked flask and cooled to 0 ° C. While stirring, an excessive amount of 3N aqueous sodium hydroxide solution was added and stirred for 6 hours. Next, 1N trifluoromethanesulfonic acid aqueous solution prepared in advance was added to make it acidic, and the resulting precipitate was filtered, washed with water, and dried to obtain 75 mg of metal complex dye Dye-5.

[Synthesis of Metal Complex Dye Dye-7]
Compound (46) was synthesized according to the synthesis scheme shown below, and metal complex dye Dye-7 was synthesized in the same manner as metal complex dye Dye-5.

(I) Synthesis of Compound (42) Sodium-tert-butoxide 2.47 g, xylene 25 ml, 4-amino-2-chloropyridine 1.5 g, 4-iodopentylbenzene 9.60 g were placed in a three-necked flask, and nitrogen was added. Replaced. While stirring, 0.534 g of tris (dibenzylideneacetone) dipalladium (0) and 0.472 g of tri-tert-butylphosphine were added, and the mixture was heated to reflux for 2 hours. The temperature was returned to room temperature, ice water and ethyl acetate were added, and the organic layer was concentrated under reduced pressure. Purification by silica gel column chromatography using hexane / ethyl acetate as an eluent gave 3.7 g of compound (42).

(Ii) Synthesis of Compound (44) Org. Chem. 2008, 73, p. Compound (43) 2.66 g, compound (42) 2.70 g, potassium triphosphate 5.45 g, 1,2-dimethoxyethane 54 ml synthesized according to the method described in 4309-4312 were placed in a three-necked flask, and nitrogen was added. Replaced. While stirring, 0.54 g of Xphos GIII was added and heated to reflux for 3 hours. After returning to room temperature and filtering through celite, the solvent was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography using hexane / ethyl acetate as an eluent to obtain 1.82 g of compound (44).

(Iii) Synthesis of Compound (45) 1.70 g of Compound (44) and 28 ml of hydrochloric acid / ethyl acetate solution were placed in a three-necked flask and allowed to stir for 1 hour. Thereafter, sodium bicarbonate water was added to carry out a liquid separation operation, and the organic layer was concentrated. By reducing the pressure at 140 ° C., 3.7 g of compound (45) was obtained.

(Iv) Synthesis of Metal Complex Dye Dye-7 A metal complex dye Dye-7 was synthesized in the same manner as metal complex dye Dye-1.

[Synthesis of Metal Complex Dye Dye-8]
In the same manner as in the metal complex dye Dye-7, a metal complex dye Dye-8 was synthesized.

[Synthesis of Metal Complex Dye-9]
In the same manner as in the metal complex dye Dye-7, a metal complex dye Dye-9 was synthesized according to the following synthesis scheme.

The synthesized metal complex dyes Dye-1 to 9 were adjusted with a 340 μmol / L tetrabutylammonium hydroxide methanol solvent so that the dye concentration would be 17 μmol / L, and spectral absorption measurement was performed. As a result, it was confirmed that all of the metal complex dyes Dye-1 to Dye-9 had a maximum absorption wavelength (λmax) at 650 nm or longer in the long wavelength region.
The ultraviolet-visible absorption spectra of Dye-1, 2, 4, 5 and 6 are shown in FIGS. Dye-1 is FIG. 10, Dye-2 is FIG. 11, Dye-4 is FIG. 12, Dye-5 is FIG. 13, and Dye-6 is FIG.
It can be seen that both have a large molar extinction coefficient ε in a long wavelength region of 700 nm or more, and in particular, those having two Ancs (two of Anc1 to Anc3) exhibit larger absorption characteristics.

  15 to 17 show visible absorption spectra of a model semiconductor film (a titanium oxide film on which a metal complex dye is adsorbed) according to Example 2 below. Dye-1 is FIG. 15, Dye-5 is FIG. 16, and Dye-6 is FIG.

<Preparation of dye-sensitized solar cell>
Example 2 [Dye-sensitized solar cell]
The following comparative compounds (1) and (2) were used as comparative metal complex dyes. Comparative compound (1) is DCSC9 described in International Publication No. 2009/082163. Comparative compound (2) is compound I-25 described in JP-A-2008-266639.

  A photoelectrode having the same configuration as the photoelectrode 12 shown in FIG. 5 described in Japanese Patent Laid-Open No. 2002-289274 is prepared by the following procedure. A 10 mm × 10 mm scale dye-sensitized solar cell 1 having the same configuration as that of the dye-sensitized solar cell 20 except for the photoelectrode described in 3 was prepared. A specific configuration is shown in FIG. 2 attached to 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 placing 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 and stirring. 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 = 30: 70. A paste was prepared.

(Production of photoelectrode 40)
A transparent electrode 41 having a fluorine-doped SnO ₂ conductive film (film thickness: 500 nm) 43 formed on a glass substrate 44 was prepared. Then, on the SnO ₂ conductive film 43, the paste 1 of the above screen printing 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 area of the semiconductor electrode (light receiving surface of the same structure as the semiconductor electrode 42 shown in FIG. 2 on SnO ₂ conductive film 43; 10 mm × 10 mm, the layer 10 μm, layer thickness of semiconductor layer 45; 6 μm, layer thickness of light scattering layer 46; 4 μm, content of rod-like TiO ₂ particles C contained in the light scattering layer; The photoelectrode 40 which does not contain was produced.

(Dye adsorption)
Next, the dye was adsorbed to the semiconductor electrode (precursor of the dye adsorption electrode) 42 as follows. First, dimethylformamide / tert-butanol = 1/1 was used as a solvent, and the metal complex dyes listed in Table 1 below were dissolved to 3 × 10 ⁻⁴ mol / L. Further, as a coadsorbent, chenodeoxycholic acid and 20 mol of an equimolar mixture of cholic acid was added to 1 mol of the metal complex dye to prepare each dye solution. When the water content of this dye solution was measured by Karl Fischer titration, the water content was less than 0.01% by mass. This dye solution contained 0.059% by mass of a metal complex dye. Next, the semiconductor electrode 42 is immersed in this solution for several hours to several tens of hours, and the immersed semiconductor electrode 42 is pulled up from the solution and then dried at 50 ° C., whereby the photoelectrode 40 having the dye adsorbed on the semiconductor electrode 42 is obtained. Each completed.

(Assembling solar cells)
Next, a platinum electrode (thickness of Pt thin film; 100 nm) having the same shape and size as the above-described photoelectrode 40 as the counter electrode CE, iodine 0.1M, lithium iodide 0.05M, 4- An iodine redox acetonitrile solution containing 0.25M t-butylpyridine was prepared. Further, a DuPont spacer S (trade name: “Surlin”) having a shape matched to the size of the semiconductor electrode 42 is prepared, and the photoelectrode 40 and the counter electrode CE are opposed to each other through the spacer S and thermocompression bonded. Each of the dye-sensitized solar cells was completed by filling the electrolyte therein. The performance of these dye-sensitized solar cells was evaluated as follows.

(Measurement of IPCE)
The IPCE (quantum yield) at 300 to 1000 nm of each dye-sensitized solar cell produced in this manner was measured with an IPCE measuring device manufactured by Pexel. Of these, IPCE at 800 nm is shown in Table 1. IPCE is expressed as “A” in terms of IPCE of the comparative compound (1), with 1.50 times or more of this IPCE being expressed as “A”, 1.01 or more and less than 1.50 times being “B”, 1.01 times Less than “C” was assigned. The results are summarized in Table 1 below.

(Measurement of photoelectric conversion efficiency)
A battery characteristic test was performed, and the photoelectric conversion efficiency (η (%)) of the metal complex dyes Dye-5, 6, and 8 was measured. The battery characteristic test was performed by irradiating 1000 W / m < ² > pseudo sunlight from the xenon lamp which passed the AM1.5 filter using the solar simulator (the product made from WACOM, WXS-85H). Current-voltage characteristics were measured using an IV tester to determine photoelectric conversion efficiency (η (%)). The photoelectric conversion efficiency (η (%)) is 1.50 times or more with respect to the comparative compound (2) as “A”, 1.10 times or more and less than 1.50 times is “B”, 1.00 “C” is defined as “double” or more and less than 1.10, and “D” is defined as less than 1.00. These results are summarized in Table 2 below.

  As is apparent from Tables 1 and 2 above, the dye-sensitized solar cell of the present invention using the metal complex dyes Dye-1 to Dye-9 of the present invention is different from the dye-sensitized solar cell using each comparative compound. , IPCE (quantum yield) was high, and photoelectric conversion efficiency (η) was excellent.

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 dye-sensitized solar cell Electric motor (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 (16)

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, wherein the photoreceptor layer carries a metal complex dye represented by the following formula (I) A photoelectric conversion element having the formed semiconductor fine particles.

(Where
M represents a metal ion.
Ring A, ring B and ring C each independently represent a nitrogen-containing aromatic heterocycle. Z ¹ and Z ² each independently represent a carbon atom or a nitrogen atom. Here, the bond between Z ¹ and the N atom and the bond between Z ² and the N atom may be a single bond or a double bond.
R ^{1 to} R ³ each independently represents a substituent having no Anc ¹ to Anc ³ . n1 and n3 each independently represents an integer of 0 to 4, and n2 represents an integer of 0 to 3. When a plurality of R ^{1 to} R ³ are present in each of them, they may be bonded to each other to form a ring.
X ¹ represents a linking group. X ² represents —O—, —S—, —NR ′ (R ′ represents a hydrogen atom or a substituent) —, a saturated aliphatic group, or an unsaturated aliphatic group having an unsaturated group that is not π-conjugated with the ring B. Represents a group, a non-aromatic hydrocarbon ring group, a non-aromatic heterocyclic group or a combination thereof. X ³ represents a single bond or a linking group. Anc1 to Anc3 each independently represents an acidic group. l1 and l3 each independently represent an integer of 1 to 4, and l2 represents an integer of 1 to 5, respectively.
m1 represents an integer of 1 to 4, m2 represents an integer of 0 to 3, and m3 represents an integer of 0 to 4, respectively.
L ^{1 to} L ³ each represents a ligand and is a bidentate ligand in which L ¹ and L ² are bonded to each other, or a tridentate ligand in which L ¹ , L ² and L ³ are bonded to each other. is there. Here, one or two of L ^{1 to} L ³ represents a ligand having an anionic coordination atom.
Y represents a counter ion necessary for neutralizing the charge, and n represents an integer of 0 to 2. ) 2. The photoelectric conversion element according to claim 1, wherein in the formula (I), the M is Fe ²⁺ , Ru ^2+, or Os ²⁺ .   In the formula (I), the ring A and the ring C are each independently a pyridine ring, pyrimidine ring, triazine ring, imidazole ring, oxazole ring, thiazole ring, oxadiazole ring, thiadiazole ring, isoxazole ring, The photoelectric conversion device according to claim 1, which is an isothiazole ring, a triazole ring or a pyrazole ring.   The photoelectric conversion element according to claim 1, wherein in the formula (I), the ring B is a pyridine ring or a pyrimidine ring. 5. The formula (I), wherein the Anc 1 to Anc 3 are each independently —COOH, —SO ₃ H, —PO ₃ H ₂ , —OH, or —SH. Photoelectric conversion element. In the formula (I), at least one of the X ¹ and the X ³ is each independently represented by any one of the following formulas (3) to (10). The photoelectric conversion element as described.

(Where
* Represents a bonding position with the ring A or the ring C.
** represents a binding position with the Anc1 or the Anc3.
s represents the integer of 0-2. R ^{31 to} R ¹⁰² represent a hydrogen atom or a substituent, and the plurality of substituents may be bonded directly or via a linking group via a linking group to form a ring. ) The formula (I), the photoelectric conversion device according to any one of claims 1 to 6 L ³ is isothiocyanate ligands. In the formula (I), the bidentate ligand in which the L ¹ and the L ² are bonded to each other is represented by any one of the following formulas (2L-1) to (2L-5) The photoelectric conversion element according to any one of claims 1 to 7.

(Where
* Represents a binding position to the metal ion M.
Ring D represents an aromatic ring.
A ^{111 to} A ^{141 each} represents an anionic nitrogen atom or carbon atom, and A ¹⁵¹ represents any one of an anionic nitrogen atom, oxygen atom or sulfur atom. R ^{111 to} R ^{154 each} represent a hydrogen atom or a substituent having no Anc1, Anc2 and Anc3. ) In the formula (I), a tridentate ligand in which the L ¹ , the L ^2, and the L ³ are bonded to each other is represented by any of the following formulas (3L-1) to (3L-5) 3 It is a bidentate ligand, The photoelectric conversion element of any one of Claims 1-6.

(Where
* Represents a binding position to the metal ion M.
Ring D represents an aromatic ring.
A ^{211 to} A ²⁴² represent a nitrogen atom or a carbon atom, and A ²⁵¹ and A ²⁵² represent a nitrogen atom, an oxygen atom, or a sulfur atom. However, at least one of A ²¹¹ and A ²¹² , A ²²¹ and A ²²² , A ²³¹ and A ²³² , A ²⁴¹ and A ²⁴² , and A ²⁵¹ and A ²⁵² is anionic. R ^{211 to} R ²⁵³ represent a hydrogen atom or a substituent that does not have Anc 1, Anc 2, and Anc 3. )   The dye-sensitized solar cell which comprises the photoelectric conversion element of any one of Claims 1-9. A metal complex dye represented by the following formula (I).

(Where
M represents a metal ion.
Ring A, ring B and ring C each independently represent a nitrogen-containing aromatic heterocycle. Z ¹ and Z ² each independently represent a carbon atom or a nitrogen atom. Here, the bond between Z ¹ and the N atom and the bond between Z ² and the N atom may be a single bond or a double bond.
R ^{1 to} R ³ each independently represents a substituent having no Anc ¹ to Anc ³ . n1 and n3 each independently represents an integer of 0 to 4, and n2 represents an integer of 0 to 3. When a plurality of R ^{1 to} R ³ are present in each of them, they may be bonded to each other to form a ring.
X ¹ represents a linking group. X ² represents —O—, —S—, —NR ′ (R ′ represents a hydrogen atom or a substituent) —, a saturated aliphatic group, or an unsaturated aliphatic group having an unsaturated group that is not π-conjugated with the ring B. Represents a group, a non-aromatic hydrocarbon ring group, a non-aromatic heterocyclic group or a combination thereof. X ³ represents a single bond or a linking group. Anc1 to Anc3 each independently represents an acidic group. l1 and l3 each independently represent an integer of 1 to 4, and l2 represents an integer of 1 to 5, respectively.
m1 represents an integer of 1 to 4, m2 represents an integer of 0 to 3, and m3 represents an integer of 0 to 4, respectively.
L ^{1 to} L ³ each represents a ligand and is a bidentate ligand in which L ¹ and L ² are bonded to each other, or a tridentate ligand in which L ¹ , L ² and L ³ are bonded to each other. is there. Here, one or two of L ^{1 to} L ³ represents a ligand having an anionic coordination atom.
Y represents a counter ion necessary for neutralizing the charge, and n represents an integer of 0 to 2. )   The pigment | dye solution formed by melt | dissolving the metal complex pigment | dye of Claim 11. In an organic solvent, the metal complex dye containing 0.001 to 0.1 wt%, and the dye solution according to claim 12 the content of water is Ru der 0.1 wt%. The pigment | dye adsorption electrode for dye-sensitized solar cells which the metal complex pigment | dye of Claim 11 carry | supported on the semiconductor fine particle surface .   The manufacturing method of the dye-sensitized solar cell assembled using each material used as the pigment | dye adsorption electrode of Claim 14, electrolyte, and a counter electrode. A metal complex represented by the following formula (II).

(Where
M represents a metal ion.
Ring A, ring B and ring C each independently represent a nitrogen-containing aromatic heterocycle. Z ¹ and Z ² each independently represent a carbon atom or a nitrogen atom. Here, the bond between Z ¹ and the N atom and the bond between Z ² and the N atom may be a single bond or a double bond.
R ^{1 to} R ³ each independently represents a substituent. n1 and n3 each independently represents an integer of 0 to 4, and n2 represents an integer of 0 to 3. When a plurality of R ^{1 to} R ³ are present in each of them, they may be bonded to each other to form a ring.
X ¹⁰ and X ³⁰ each independently represent a single bond or a linking group. X ²⁰ represents a single bond or —O—, —S—, —NR ′ (R ′ represents a hydrogen atom or a substituent) —, a saturated aliphatic group, an unsaturated group that does not π-conjugated with the ring B. A saturated aliphatic group, a non-aromatic hydrocarbon ring group, a non-aromatic heterocyclic group, or a combination thereof is represented.
G represents an aldehyde group or an acetal group which is represented by any one of the following structures and may have a substituent.
p1 represents an integer of 1 to 4, p2 represents an integer of 0 to 3, and p3 represents an integer of 0 to 4, respectively.
L ^{1 to} L ³ each represents a ligand, both of which are monodentate ligands, a bidentate ligand in which L ¹ and L ² are bonded to each other, or L ¹ , L ² and L ³ are bonded to each other Tridentate ligand. Here, one or two of L ^{1 to} L ³ represents a ligand having an anionic coordination atom.
Y represents a counter ion necessary for neutralizing the charge, and n represents an integer of 0 to 2. )

(In the formula, each R ^G independently represents an alkyl group. * Represents a bonding position with X ¹⁰ , X ²⁰ or X ^30. )

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