WO2016052196A1

WO2016052196A1 - Photoelectric conversion element, dye-sensitized solar cell, metal complex dye, dye solution, and terpyridine compound or esterification product thereof

Info

Publication number: WO2016052196A1
Application number: PCT/JP2015/076264
Authority: WO
Inventors: 知昭吉岡; 渡辺　康介; 小林　克
Original assignee: 富士フイルム株式会社
Priority date: 2014-09-29
Filing date: 2015-09-16
Publication date: 2016-04-07
Also published as: TW201612175A

Abstract

Provided are: a photoelectric conversion element that comprises a conductive support body, a photosensitive layer containing an electrolyte, a charge transfer layer containing an electrolyte, and a counter electrode, wherein the photosensitive layer comprises fine semiconductor particles having a metal complex dye that is represented by formula (I) loaded thereon; a dye-sensitized solar cell; a metal complex dye used in the photoelectric conversion element and the dye-sensitized solar cell; a dye solution; and a terpyridine compound or an esterification product thereof. Formula (I): M(LA)(LD)_p(LX)_q∙(CI)_z. In formula (I), M represents a metal ion. LD represents a bidentate or tridentate ligand. p represents 0 or 1. LX represents a monodentate ligand. q represents 0, 1, or 3. CI represents a counterion. z represents an integer of 0-3. LA represents a tridentate ligand that is represented by formula (LA-1). In formula (LA-1), Za, Zb, and Zc each represent a non-metal atom group that is necessary in order to complete a 5- or 6-membered ring. At least one of the Za ring and the Zb ring comprises an acidic group. R¹ and R² each represent an alkyl group or an aromatic ring group.

Description

Photoelectric conversion element, dye-sensitized solar cell, metal complex dye, dye solution, and terpyridine compound or esterified product thereof

The present invention relates to a photoelectric conversion element, a dye-sensitized solar cell, a metal complex dye, a dye solution, and a terpyridine compound or an esterified product thereof.

Photoelectric conversion elements are used in various photosensors, photocopiers, photoelectrochemical cells such as solar cells, and the like. Various methods such as a method using a metal, a method using a semiconductor, a method using an organic pigment or a dye, or a combination of these have been put to practical use for this photoelectric conversion element. In particular, a solar cell using non-depleting solar energy does not require fuel, and full-scale practical use is highly expected as it uses inexhaustible clean energy. Among them, silicon-based solar cells have been researched and developed for a long time, and are spreading due to national policy considerations. However, since silicon is an inorganic material, there is a limit to improving throughput and cost.

Therefore, research on photoelectrochemical cells (also called dye-sensitized solar cells) using metal complex dyes has been vigorously conducted. In particular, it was the research results of Graetzel, etc., Lausanne University of Technology, Switzerland. They adopted a structure in which a dye composed of a ruthenium complex was fixed on the surface of a porous titanium oxide film, realizing photoelectric 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.

After the report of Graetzel et al., Dyes called N3, N719, N749 (also referred to as black dye), Z907, and J2 have been developed as metal complex dyes used in dye-sensitized solar cells.

In addition to these dyes, development of metal complex dyes that improve the photoelectric conversion efficiency or durability of photoelectric conversion elements and dye-sensitized solar cells is in progress.
For example, Patent Document 1 discloses a terpyridine ligand and three benzene ring groups or thiophene ring groups containing an amino group bonded to the 3-position of the ring nitrogen atom coordinated to the metal ion of the terminal pyridine ring. Metal complex dyes having a monodentate ligand are described. It is also described that the photoelectrochemical cell using this metal complex dye achieved high photoelectric conversion efficiency and was excellent in durability.
Patent Document 2 discloses a tridentate ligand in which a thiophene ring group having a diphenylaminophenyl group is bonded to the 3-position of a ring-constituting nitrogen atom coordinated to a metal ion of an α-pyridine ring, and Describe metal complexes having this ligand and three isothiocyanate anions.
Furthermore, Patent Document 3 describes a metal complex dye having a terpyridine ligand having a terminal pyridine ring to which a C ₂₉ H ₅₉ CONH group is bonded and three isothiocyanate anions. It is also described that a photoelectrochemical cell using this metal complex dye has high photoelectric conversion efficiency and excellent durability.
Patent Document 4 discloses a terpyridine ligand in which a benzene ring group having an alkoxy group is bonded to the ring-constituting nitrogen atom coordinated to the metal ion of the terminal pyridine ring, and a specific substituent. Metal complex dyes having a donor ligand with a cyclic group substituted with. It is also described that the photoelectrochemical cell using this metal complex dye can achieve both reduction in performance variation and improvement in photoelectric conversion efficiency and durability.

JP 2013-67773 A US Patent Application Publication No. 2012/0247561 JP 2012-36237 A JP 2013-229285 A

However, in recent years, research and development of photoelectric conversion elements and dye-sensitized solar cells have been actively performed, and the required performance has become higher. In particular, further improvement and improvement in photoelectric conversion efficiency and durability are desired.

By the way, in the manufacture of the photoelectric conversion element and the dye-sensitized solar cell, usually, the metal complex dye is adsorbed to the semiconductor fine particles by bringing the semiconductor fine particles and the metal complex dye into contact with each other for a long time at a temperature of about room temperature. However, shortening the adsorption time of the metal complex dye often reduces the amount of adsorption of the metal complex dye adsorbed on the semiconductor fine particles. Therefore, the photoelectric conversion efficiency of a photoelectric conversion element and a dye-sensitized solar cell falls. Therefore, in order to manufacture by shortening the adsorption time, it is desired that the metal complex dye has a high adsorption rate or can impart excellent photoelectric conversion efficiency even with a small adsorption amount.

The present invention has a small influence of the adsorption time of the metal complex dye on the photoelectric conversion efficiency, and particularly exhibits excellent photoelectric conversion efficiency even when manufactured by shortening the adsorption time, and has high durability. Photoelectric conversion element and dye sensitization It is an object of the present invention to provide a solar cell, and a metal complex dye, a dye solution, and a terpyridine compound or an esterified product thereof used therein.

Conventionally, in order to improve the photoelectric conversion efficiency of photoelectric conversion elements and dye-sensitized solar cells, the conjugated structure of the ligand coordinated to the metal complex dye is extended, and an electron donating group is further introduced into the ligand It has been considered to do. As a result, the absorption characteristics of metal complex dyes have been made longer, which has been an effective means for improving photoelectric conversion efficiency. However, according to the study by the present inventors, the extension of the conjugated structure and the introduction of an electron donating group, which have been effective for improving the photoelectric conversion efficiency so far, can reduce the photoelectric conversion efficiency, particularly the adsorption time. It was found that it was difficult to achieve both higher photoelectric conversion efficiency and higher durability. Therefore, the present inventors have further studied, and introduced a photoelectric conversion element and a dye-sensitized solar cell by directly introducing an electron-donating amino group into a ligand having an adsorbing group without using a conjugated group. It has been found that the metal complex dye sufficiently exhibits the above-described excellent characteristics even when the battery is produced by further improving the photoelectric conversion efficiency and durability and shortening the adsorption time. The present invention has been completed based on these findings.

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 metal complex dye.

Formula (I) M (LA) (LD) _p (LX) _q · (CI) _z

In the formula, M represents a metal ion.
LA represents a tridentate ligand represented by the following formula (LA-1).
LD represents a bidentate or tridentate ligand. p represents 0 or 1;
LX represents a monodentate ligand. q represents 3 when p is 0, represents 0 when p is 1 and LD is a tridentate ligand, and represents 1 when p is 1 and LD is a bidentate ligand. .
CI represents a counter ion necessary for neutralizing the charge of the metal complex dye. z represents an integer of 0 to 3.

In the formula, Za, Zb and Zc each independently represent a group of nonmetallic atoms necessary to complete a 5-membered or 6-membered ring. However, at least one of the rings formed by Za and Zb has an acidic group. R ¹ and R ² each independently represents an alkyl group or an aromatic ring group.

<2> The ring formed by Za, the ring formed by Zb, and the ring formed by Zc are each independently a pyridine ring, pyrimidine ring, pyrazine ring, pyridazine ring, triazine ring, tetrazine ring, quinoline ring, imidazole ring, The photoelectric conversion element according to <1>, which is at least one selected from the group consisting of a triazole ring, a thiazole ring, an oxazole ring, a benzimidazole ring, a benzotriazole ring, a benzoxazole ring, and a benzothiazole ring.
<3> The photoelectric conversion element according to <1> or <2>, in which M is Ru ²⁺ or Os ²⁺ .
<4> The photoelectric conversion device according to any one of <1> to <3>, wherein LA is represented by the following formula (LA-2).

Wherein, ^{R 1} and ^{R 2} are each the same meaning as ^{R 1} and ^{R 2} of formula (LA-1). Anc1 and Anc2 each independently represent an acidic group.

<5> The photoelectric conversion element according to any one of <1> to <4>, wherein R ¹ and R ² are both aryl groups.
<6> The photoelectric conversion element according to any one of <1> to <5>, wherein the acidic group is a carboxy group or a salt thereof.
<7> The LD is a bidentate ligand represented by any one of the following formulas (2L-1) to (2L-4), and any one of <1> to <6> Photoelectric conversion element.

In the formula, ring D ^2L represents an aromatic ring. A ¹¹¹ to A ¹⁴¹ each independently represents an anion of a nitrogen atom or an anion of a carbon atom. R ¹¹¹ to R ¹⁴³ each independently represents a hydrogen atom or a substituent having no acidic group. * Represents a coordination position to the metal ion M.

<8> The LD is a tridentate ligand represented by any one of the following formulas (3L-1) to (3L-4): <1> to any one of <6> Photoelectric conversion element.

In the formula, ring D ^2L represents an aromatic ring. A ²¹¹ to A ²⁴² each independently represents a nitrogen atom or a carbon atom. However, in each of A ²¹¹ and A ²¹² , A ²²¹ and A ²²² , A ²³¹ and A ²³² , and A ²⁴¹ and A ²⁴² , at least one is an anion. R ²¹¹ to R ²⁴¹ each independently represent a hydrogen atom or a substituent having no acidic group. * Represents a coordination position to the metal ion M.

<9> A dye-sensitized solar cell including the photoelectric conversion element according to any one of <1> to <8>.
<10> A metal complex dye represented by the following formula (I).

Formula (I) M (LA) (LD) _p (LX) _q · (CI) _z

<11> A dye solution containing the metal complex dye according to <10> and a solvent.
<12> A terpyridine compound represented by the following formula (LA-2) or an esterified product thereof.

In the formula, R ¹ and R ² each independently represents an alkyl group or an aromatic ring group. Anc1 and Anc2 each independently represent an acidic group.

In the present specification, unless otherwise specified, the 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 simultaneously defining a plurality of substituents, etc., unless otherwise specified, The substituents and the like may be the same as or different from each other. 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 the present invention, the ring has the following meanings unless otherwise specified. The same applies to the cyclic group.
In the present invention, the number of ring members is not particularly limited, but is preferably 4 to 8 members, more preferably 5 or 6 members. The ring may be a condensed ring. That is, the ring includes a single ring and a polycycle (condensed ring) formed by condensing a plurality of rings. The number of rings forming the polycycle (the number of condensed rings) is not particularly limited, and is preferably 2 to 5 rings, for example.

In the present invention, the ring includes an aromatic ring and an aliphatic ring.
The aromatic ring includes an aromatic hydrocarbon ring and an aromatic heterocycle. An aromatic hydrocarbon ring refers to a hydrocarbon ring exhibiting aromaticity. Although not particularly limited, for example, a benzene ring is exemplified as the monocyclic aromatic hydrocarbon ring, and a naphthalene ring and a fluorene ring are exemplified as the polycyclic aromatic hydrocarbon ring. The aromatic heterocycle refers to a heterocycle exhibiting aromaticity, and includes a monocyclic aromatic heterocycle and a polycyclic aromatic heterocycle. The aromatic hydrocarbon ring group is also referred to as an aryl group or an arylene group depending on the valence, and similarly, the aromatic heterocyclic group is also referred to as a heteroaryl group or a heteroarylene group.
An aliphatic ring refers to a ring other than an aromatic ring, and includes an aliphatic hydrocarbon ring and an aliphatic hetero ring. Examples of the aliphatic hydrocarbon ring include a saturated hydrocarbon ring and an unsaturated hydrocarbon ring that does not exhibit aromaticity. For example, monocyclic saturated hydrocarbon ring (cycloalkane), polycyclic saturated hydrocarbon ring, monocyclic unsaturated hydrocarbon ring (cycloalkene, cycloalkyne), polycyclic unsaturated hydrocarbon ring and the like can be mentioned. .
An aromatic heterocycle and an aliphatic heterocycle may be collectively referred to as a heterocycle. A heterocycle refers to a ring having a ring atom composed of a carbon atom and a heteroatom (for example, a nitrogen atom, an oxygen atom, a sulfur atom, a silicon atom, a selenium atom, or a phosphorus atom).

In this specification, the display of a compound (including a complex and a dye) is used to mean not only the compound itself but also its salt and its ion. Moreover, it is the meaning including what changed a part of structure in the range which does not impair the target effect. Furthermore, the compounds that do not specify substitution or non-substitution include those having an arbitrary substituent as long as the intended effect is not impaired. As such a substituent, a substituent selected from the substituent group T described later is preferably exemplified. The same applies to substituents, linking groups and ligands.

In addition, in this specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

The photoelectric conversion element and the dye-sensitized solar cell of the present invention have a metal complex dye formed by directly introducing an amino group into the ligand LA. Thereby, the influence of the adsorption time of the metal complex dye on the photoelectric conversion efficiency is small. In particular, even if the adsorption time is shortened, excellent photoelectric conversion efficiency and high durability are exhibited. Therefore, according to the present invention, the influence of the adsorption time of the metal complex dye on the photoelectric conversion efficiency is small, and in particular, even if the adsorption time is shortened, the photoelectric conversion element and the dye-sensitized solar exhibit excellent photoelectric conversion efficiency and high durability. Batteries and metal complex dyes, dye solutions, and terpyridine compounds or esterified products thereof can be provided.
The above and other features and advantages of the present invention will become more apparent from the following description, with reference where appropriate to the accompanying drawings.

FIG. 1 is a cross-sectional view schematically showing an enlarged view of a circular portion in a layer in a system in which the photoelectric conversion element according to the first aspect of the present invention is applied to a battery. FIG. 2 is a cross-sectional view schematically showing a dye-sensitized solar cell including the photoelectric conversion element according to the second aspect of the present invention.

[Photoelectric conversion element and dye-sensitized solar cell]
The photoelectric conversion element of the present invention has a conductive support, a photoreceptor layer containing an electrolyte, a charge transfer body layer containing an electrolyte, and a counter electrode (counter electrode). The photosensitive layer, the charge transfer layer, and the counter electrode are provided on the conductive support in this order.

In the photoelectric conversion element of the present invention, at least a part of the semiconductor fine particles forming the photoreceptor layer carries a metal complex dye represented by the formula (I) described later as a sensitizing dye. Here, the aspect in which the metal complex dye is supported on the surface of the semiconductor fine particle includes an aspect in which the metal complex dye is adsorbed on the surface of the semiconductor fine particle, an aspect in which the metal complex dye is deposited on the surface of the semiconductor fine particle, and an aspect in which these are mixed. The adsorption includes chemical adsorption and physical adsorption, and chemical adsorption is preferable.
The semiconductor fine particles may carry another metal complex dye together with the metal complex dye of the formula (I) described later.
It is preferable that the semiconductor fine particles carry a co-adsorbent described later together with the metal complex dye.

The photoreceptor layer contains an electrolyte. The electrolyte contained in the photoreceptor layer may be the same as or different from the electrolyte of the charge transfer layer, but is preferably the same. Here, “the same type of electrolyte” means that the component contained in the electrolyte of the photoreceptor layer and the component contained in the electrolyte of the charge transfer layer are the same, and the content of each component is the same, and The components included in the electrolyte of the photoreceptor layer and the components included in the electrolyte of the charge transfer layer are the same, but include the aspects in which the content of each component is different.

The photoelectric conversion element of the present invention is not particularly limited in structure other than the structure defined in the present invention, and a known structure relating to the photoelectric conversion element can be adopted. Each of the layers constituting the photoelectric conversion element of the present invention is designed according to the purpose, and may be formed in a single layer or multiple layers, for example. Moreover, you may have layers other than said each layer if needed.

The dye-sensitized solar cell of the present invention uses the photoelectric conversion element of the present invention.
Hereinafter, preferred embodiments of the photoelectric conversion element and the dye-sensitized solar cell of the present invention will be described.

A system 100 shown in FIG. 1 is an application of the photoelectric conversion element 10 according to the first aspect of the present invention to a battery application in which an operation means M (for example, an electric motor) is caused to work by an external circuit 6.
The photoelectric conversion element 10 includes a conductive support 1, semiconductor fine particles 22 sensitized by supporting a dye (metal complex dye) 21, and a photoreceptor layer 2 including an electrolyte between the semiconductor fine particles 22, It consists of a charge transfer layer 3 that is a hole transport layer and a counter electrode 4.
In the photoelectric conversion element 10, the light receiving electrode 5 includes the conductive support 1 and the photoreceptor layer 2, and functions as a working electrode.

In the system 100 to which the photoelectric conversion element 10 is applied, the light incident on the photoreceptor layer 2 excites the metal complex dye 21. The excited metal complex dye 21 has high energy electrons, and these electrons are transferred from the 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 metal complex dye 21 is an oxidant (cation). Electrons that have reached the conductive support 1 work in the external circuit 6, reach the oxide of the metal complex dye 21 via the counter electrode 4 and the charge transfer layer 3, and reduce this oxide. The system 100 functions as a solar cell.

The dye-sensitized solar cell 20 shown in FIG. 2 is configured by the photoelectric conversion element of the second aspect of the present invention.
Although the photoelectric conversion element used as the dye-sensitized solar cell 20 differs with respect to the photoelectric conversion element shown in FIG. 1 by the structure of the electroconductive support body 41 and the photoreceptor layer 42, and the point which has the spacer S, those photoelectric conversion elements are different. Except for this point, the photoelectric conversion element 10 is configured in the same manner as the photoelectric conversion element 10 shown in FIG. That is, the conductive support 41 has a two-layer structure including a substrate 44 and a transparent conductive film 43 formed on the surface of the substrate 44. The photoreceptor layer 42 has a two-layer structure including a semiconductor layer 45 and a light scattering layer 46 formed adjacent to the semiconductor layer 45. A spacer S is provided between the conductive support 41 and the counter electrode 48. In the dye-sensitized solar cell 20, reference numeral 40 denotes a light receiving electrode, and 47 denotes a charge transfer body layer.

The dye-sensitized solar cell 20 functions as a solar cell when light enters the photoreceptor layer 42 as in the system 100 to which the photoelectric conversion element 10 is applied.

The photoelectric conversion element and the dye-sensitized solar cell of the present invention are not limited to the above-described preferred embodiments, and the configurations and the like of each embodiment can be appropriately combined between the respective embodiments without departing from the gist of the present invention.

In the present invention, materials and members used for the photoelectric conversion element or the dye-sensitized solar cell can be prepared by a conventional method. For example, US Pat. No. 4,927,721, US Pat. No. 4,684,537, US Pat. No. 5,084,365, US Pat. No. 5,350,644, U.S. Pat. No. 5,463,057, U.S. Pat. No. 5,525,440, JP-A-7-249790, JP-A 2001-185244, JP-A 2001-210390, JP Reference can be made to JP2003-217688A, JP2004220974A, and JP2008-135197A.

<Metal Complex Dye Represented by Formula (I)>
The metal complex dye of the present invention is represented by the following formula (I). Since the metal complex dye of the present invention has the ligand LA represented by the following formula (LA-1), the influence of the adsorption time of the metal complex dye on the photoelectric conversion efficiency is small, and particularly the adsorption time is shortened. Can maintain excellent characteristics. Therefore, even if it is a photoelectric conversion element and a dye-sensitized solar cell manufactured especially shortening adsorption time, high photoelectric conversion efficiency and the outstanding thermal stability can be provided. Therefore, the metal complex dye of the present invention is preferably used as a sensitizing dye in a dye-sensitized solar cell.

Formula (I) M (LA) (LD) _p (LX) _q · (CI) _z

In the formula (I), M represents a metal ion.
LA represents a tridentate ligand represented by the following formula (LA-1).

In the formula (LA-1), Za, Zb and Zc each independently represent a nonmetallic atom group necessary for forming a 5-membered or 6-membered ring. However, at least one of the rings formed by Za and Zb has an acidic group.
R ¹ and R ² each independently represents an alkyl group or an aromatic ring group.

In the formula (I), LD represents a bidentate or tridentate ligand. p represents 0 or 1; It is preferable that p is 1 at the point which can provide the durable excellent to a photoelectric conversion element and a solar cell.
LX represents a monodentate ligand. q represents 3 when p is 0, represents 0 when p is 1 and LD is a tridentate ligand, and represents 1 when p is 1 and LD is a bidentate ligand. .

CI represents a counter ion necessary for neutralizing the charge of the metal complex dye. z represents an integer of 0 to 3, preferably 0 or 1, and more preferably 0.

-Metal ion M-
M is a central metal of the metal complex dye, and examples thereof include ions of each element of Groups 6 to 12 on the long periodic table. Examples of such metal ions include Ru, Fe, Os, Cu, W, Cr, Mo, Ni, Pd, Pt, Co, Ir, Rh, Re, Mn, and Zn ions. The metal ion M may be one kind of ion or two or more kinds of ions.
In the present invention, the metal ion M is preferably Os ²⁺ , Ru ²⁺ or Fe ²⁺ , more preferably Os ²⁺ or Ru ²⁺ , and particularly preferably Ru ²⁺ .
In the state incorporated in the photoelectric conversion element, the valence of M may change due to an oxidation-reduction reaction with surrounding materials.

-Ligand LA-
The ligand LA is a tridentate ligand (compound) represented by the formula (LA-1) and coordinated to the metal ion M by three nitrogen atoms.
The ligand LA has a function of supporting the metal complex dye of the present invention on the semiconductor fine particles by an acidic group (also referred to as an adsorbing group) included in at least one of a ring formed by Za and a ring formed by Zb.

The ligand LA has an amino group (—NR ¹ R ² ) at the ring constituent atom of the ring formed by Zc. In the ligand LA, when an amino group is directly bonded to the ring-constituting carbon atom of Zc, for example, it is considered that the LUMO (lowest orbital) energy level of the metal complex dye increases. Further, it is considered that the two groups R ¹ and R ² possessed by the amino group can cover the surface of the semiconductor fine particles widely. Photoelectric conversion elements and dye-sensitized solar cells containing such a metal complex dye in the photoreceptor layer have improved photoelectric conversion efficiency. This is considered to be able to reduce the influence of the adsorption time for realizing the desired photoelectric conversion efficiency, and particularly to produce excellent photoelectric conversion efficiency even if the adsorption time is shortened. It is done. Furthermore, durability of the photoelectric conversion element and the dye-sensitized solar cell is also improved.
Further, when an amino group is bonded to the ring-forming atom at the 4-position with respect to the ring-forming nitrogen atom coordinated to the metal ion of the ring formed by Zc, the LUMO energy level is increased and the coverage of the semiconductor fine particles is further increased. It is thought to grow. Therefore, in addition to the improvement in durability, further improvement in photoelectric conversion efficiency can be achieved.
Therefore, this ligand LA is preferably used as a ligand of a metal complex dye used in a dye-sensitized solar cell.

In the formula (LA-1), Za, Zb and Zc are preferably a nonmetallic atom group selected from a carbon atom and the above hetero atom, and selected from a carbon atom, a nitrogen atom, an oxygen atom, a sulfur atom and a phosphorus atom. More preferably, it is a nonmetallic atom group.
The ring formed by Za, Zb and Zc is preferably a 5-membered aromatic heterocycle or a 6-membered aromatic heterocycle. These rings include a condensed ring in which at least one of an aromatic ring and an aliphatic ring is condensed in addition to a single ring. Moreover, the ring formed by Za and the ring formed by Zb may preferably have a substituent selected from the substituent group T described later. Further, a condensed ring in which rings formed by Za and Zb are bonded to each other through this substituent may be formed. Examples of such a condensed ring include a 1,10-phenanthroline ring.

The 5-membered aromatic heterocycle may be a 5-membered ring containing the above heteroatoms as ring-constituting atoms. For example, at least one of a pyrazole ring, an imidazole ring, a triazole ring, a thiazole ring, an oxazole ring, a benzoimidazole ring, a benzotriazole ring, a benzoxazole ring, and a benzothiazole ring is preferable. The 6-membered aromatic heterocycle may be a 6-membered ring containing the above heteroatom as a ring-constituting atom. For example, at least one of pyridine ring, pyrimidine ring, pyrazine ring, pyridazine ring, triazine ring, tetrazine ring, quinoline ring and isoquinoline ring is preferable.
The rings formed by Za, Zb, and Zc are at least one selected from the group consisting of the group of the 5-membered aromatic heterocycle and the group of the 6-membered aromatic heterocycle. An aromatic heterocycle that matches the structure of each ring represented by -1) is preferably selected.

Specifically, the ring formed by Za is a pyridine ring, pyrimidine ring, pyrazine ring, pyridazine ring, triazine ring, tetrazine ring, quinoline ring, isoquinoline ring, imidazole ring, pyrazole ring, triazole ring, thiazole ring, oxazole ring. , A benzimidazole ring, a benzotriazole ring, a benzoxazole ring, and a benzothiazole ring. The ring formed by Zb is a pyridine ring, pyrimidine ring, pyrazine ring, pyridazine ring, triazine ring, tetrazine ring, quinoline ring, isoquinoline ring, imidazole ring, triazole ring, thiazole ring, oxazole ring, benzimidazole ring, benzoid ring, It is preferably at least one selected from the group consisting of a triazole ring, a benzoxazole ring and a benzothiazole ring. Furthermore, it is preferably at least one of a pyridine ring, a pyrimidine ring, a pyridazine ring, a triazine ring, a tetrazine ring and a quinoline ring.
The rings formed by Za, Zb and Zc are respectively a pyridine ring, a pyrimidine ring, a pyrazine ring, a pyridazine ring, a triazine ring, a tetrazine ring, a quinoline ring, an imidazole ring, a triazole ring, a thiazole ring, an oxazole ring, a benzimidazole ring, More preferably, it is at least one selected from the group consisting of a benzotriazole ring, a benzoxazole ring and a benzothiazole ring.
Of these, the rings formed by Za, Zb and Zc are each more preferably an imidazole ring, a pyridine ring or a pyrimidine ring, and particularly preferably all are pyridine rings.

At least one of the rings formed by Za and Zb has an acidic group. Both of these rings preferably have at least one acidic group. The number of acidic groups each of the heterocycles formed by Za and Zb is preferably 1 to 3, more preferably 1 or 2, and further preferably 1. More preferably, each of these rings has one acidic group. The substitution position of the acidic group is not particularly limited. As a substitution position, each ring preferably has a ring constituent atom that is furthest away from the nitrogen atom coordinated to the metal ion M. For example, when the ring formed by Za and Zb is a six-membered ring, the metal ion M A ring-constituting atom at the 4-position with respect to the ring-constituting nitrogen atom is exemplified.

In the present invention, an acidic group is a substituent having a dissociative proton, and a pKa of 11 or less. The pKa of the acidic group is determined by J.M. Phys. Chem. A2011, 115, 6641-6645 can be obtained according to the “SMD / M05-2X / 6-31G ^* ” method. Examples of the acidic group include acid groups exhibiting acidity such as a carboxy group, a phosphonyl group, a phosphoryl group, a sulfo group, and a boric acid group, or groups having these acid groups. Examples of the group having an acid group include a group having an acid group and a linking group. The linking group is not particularly limited, and examples thereof include a divalent group, and preferable examples include an alkylene group, an alkenylene group, an alkynylene group, an arylene group, and a heteroarylene group. This linking group may have a group selected from the substituent group T described later as a substituent. As the acidic group having an acid group and a linking group, for example, carboxymethyl, carboxyvinylene, dicarboxyvinylene, cyanocarboxyvinylene, 2-carboxy-1-propenyl, 2-carboxy-1-butenyl, carboxyphenyl and the like are preferable. Can be mentioned.
The acidic group is preferably a group having a carboxy group, a phosphonyl group, a sulfo group or a carboxy group, and more preferably a carboxy group.

The acidic group may be an anion dissociated by releasing a proton when incorporated into the metal complex dye represented by the formula (I), or may be a salt. Although it does not specifically limit as a counter ion when an acidic group turns into a salt, For example, the example of the positive ion in the following counter ion CI is mentioned. The acidic group may be esterified as described later.

In the ring formed by Zc, the ring atom to which the amino group (—NR ¹ and R ² ) is bonded is not particularly limited, but with respect to the ring nitrogen atom coordinated to the metal ion of the ring formed by Zc, The 3-position, 4-position or 5-position is preferred, and the 4-position is particularly preferred.

R ¹ and R ² are each independently an alkyl group or an aromatic ring group.
The alkyl group preferably has 1 to 24 carbon atoms, and more preferably 1 to 12 carbon atoms. The alkyl group may be linear, branched or cyclic, but is preferably a linear or branched alkyl group. Examples of the alkyl group include methyl, ethyl, isopropyl, n-butyl, t-butyl, isobutyl, n-hexyl, n-octyl, 2-ethylhexyl, 3,7-dimethyloctyl, 2-butyloctyl and n-dodecyl. N-hexadecyl and 2-hexyldecyl, and t-butyl, n-hexyl, 2-ethylhexyl and n-octyl are preferred.
The aromatic ring group includes an aryl group or a heteroaryl group.
The aryl group preferably has 6 to 24 carbon atoms, and more preferably 6 to 18 carbon atoms. In the present invention, the aryl group may be a group consisting of an aromatic hydrocarbon ring, and may be a condensed ring group in which at least one of another aromatic hydrocarbon ring and an aliphatic hydrocarbon ring is condensed. Aryl groups include phenyl, naphthyl, fluorenyl, biphenyl, anthracenyl. The aryl group as R ¹ and R ² is preferably phenyl, naphthyl or fluorenyl, more preferably phenyl.
The heteroaryl group preferably has 0 to 24 carbon atoms, and more preferably 1 to 18 carbon atoms. The aromatic heterocycle forming the heteroaryl group is not particularly limited, and examples thereof include an aromatic heterocycle having the above hetero atom as a ring constituent atom. Examples of the aromatic heterocycle include, in addition to the 5-membered aromatic heterocycle and the 6-membered aromatic heterocycle described in the ring formed by Za, a thiophene ring, a furan ring, a silole ring, and a phosphole ring. And a selenophene ring.

At least one of R ¹ and R ² is preferably an aryl group or a heteroaryl group, more preferably an aryl group or a heteroaryl group from the viewpoint of photoelectric conversion efficiency, and both are an aryl group. Particularly preferred.

R ¹ and R ² may not be bonded to each other, and may be bonded to each other to form a ring. The nitrogen-containing cyclic group formed by combining R ¹ and R ² is not particularly limited, and may be an aromatic cyclic group or an aliphatic cyclic group. Examples of such nitrogen-containing ring groups include morpholine ring groups, thiomorpholine ring groups, piperidine ring groups, and the following nitrogen-containing ring groups.

Here, R ^DA3 and R ^DA4 each independently represent an alkyl group or an aryl group. Alkyl and aryl group has the same meaning as alkyl or aryl group of R ¹ and R ^2, and preferred ones are also the same.
Each of the above nitrogen-containing ring groups may have a substituent. Examples of the substituent that these rings may have include a substituent selected from the substituent group T described later. Also, the number of substituents is not particularly limited. When it has a plurality of substituents, the same substituent or different substituents may be used.

R ¹ and R ² may each independently have a substituent. The R ¹ and R ² substituents which may have, respectively, but are not limited to, include groups selected from Substituent Group T described later. Of these, an alkyl group, an aryl group, an alkoxy group, an alkylthio group, a silyl group, a halogen atom and an amino group are preferable, and an alkyl group, an aryl group, an alkoxy group and an alkylthio group are more preferable.

The N, N-dialkylamino group in which R ¹ and R ² are both alkyl groups is not particularly limited. For example, N, N-dimethylamino, N, N-diethylamino, N, N-dipropylamino, N , N-dipentylamino, N, N-bis (n-hexyl) amino, N-methyl-Nn-hexylamino, N, N-bis (2-ethylhexyl) amino, N, N-bis (n-octyl) ) Amino, N, N-bis (n-decyl) amino and the like.
The N, N-diarylamino group in which R ¹ and R ² are both aryl groups is not particularly limited. For example, N, N-diphenylamino, N, N-di (4-methylphenyl) amino, N, N-di (4- (t-butyl) phenyl) amino, N, N-di (4- (n-hexyl) phenyl) amino, N, N-di (4-methoxyphenyl) amino, N, N-di (4- (n-octyloxy) phenyl) amino, N, N-di (4-trimethylsilylphenyl) amino, N, N-di (3,5-dimethylphenyl) amino, N, N-di (4-dimethyl) Aminophenyl) amino, N, N-di (4-methylthiophenyl) amino, N, N-di (4-biphenyl) amino, N, N-dinaphthylamino, N, N-difluorenylamino, N, N -Di (4-Diff Nylaminophenyl) amino, N, N-di (4-fluorophenyl) amino, N, N-di (4-trifluoromethylphenyl) amino, N, N-di (4-chlorophenyl) amino, N-methoxyphenyl -N-naphthylamino, 4,7-di (t-butylcarbazoyl) amino and the like.
N, N-diheteroarylamino groups in which R ¹ and R ² are both heteroaryl groups include N, N-dithienylamino, N, N-di (4-alkylthienyl) amino, N, N-di (4- (n-hexyl) thienyl) amino, N, N-di (3-pyridyl) amino and the like.

The ligand LA is preferably a tridentate ligand (terpyridine compound) represented by the following formula (LA-2).

Wherein, ^{R 1} and ^{R 2} are each the same meaning as ^{R 1} and ^{R 2} in the formula (LA-1), it is preferable also the same.
Anc1 and Anc2 each independently represent an acidic group. The acidic group is synonymous with the acidic group of formula (LA-1), and preferred ones are also the same.

The ligand LA is more preferably a tridentate ligand represented by the following formula (LA-3). The tridentate ligand represented by the formula (LA-3) has a diphenylamino group at the 4-position with respect to the nitrogen atom constituting the pyridine ring. When such a tridentate ligand LA is introduced into the photoelectric conversion element and the metal complex dye contained in the photoreceptor layer of the dye-sensitized solar cell, the photoelectric conversion efficiency and durability are further improved.

In the formula, R ¹¹ to R ²⁰ each independently represents a hydrogen atom or a substituent. The substituents that can be taken as R ¹¹ to R ^{20 are the same} as the substituents that R ¹ and R ² can take, and the preferred ones are also the same. Two of R ¹¹ to R ²⁰ which are adjacent may be connected to each other to form a ring.
Anc1 and Anc2 each independently represent an acidic group. The acidic group is synonymous with the acidic group of formula (LA-1), and preferred ones are also the same.

Each of the above terpyridine compounds is the ligand LA itself, but in the present invention, the ligand LA can also be used as a precursor compound of the ligand LA as described later. Therefore, in the present invention, the ligand LA includes a precursor compound of the ligand LA in addition to the ligand LA itself (the terpyridine compound). Preferable precursor compounds include ester bodies in which at least one of Anc1 and Anc2 of the terpyridine compound is esterified (also referred to as an esterified product of a terpyridine compound).
This esterified compound is a compound in which the acidic group is protected and can be regenerated to an acidic group by hydrolysis or the like, and is not particularly limited. Examples thereof include alkyl esterified products, aryl esterified products, and heteroaryl esterified products of the above acidic group. Among these, alkyl esterified products are preferable. The alkyl group forming the alkyl esterified product is not particularly limited, but is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, and further preferably an alkyl group having 1 to 4 carbon atoms. The aryl group forming the aryl esterified product and the heteroaryl group forming the heteroaryl esterified product are not particularly limited, and examples thereof include those exemplified in the substituent group T described later. These groups may have one or more substituents selected from the substituent group T described later.
The acidic group to be esterified is preferably two of Anc1 and Anc. In this case, the two esters may be the same or different.

The ligand LA can be synthesized by a usual method. For example, the ligand LA represented by the formula (L1-4) includes a compound represented by the formula (L1-1) and a compound represented by the formula (L1-2) as shown in the following scheme. It can be synthesized by a coupling reaction and hydrolyzing the ester group of the precursor compound represented by the formula (L1-3). In this synthesis method, an esterified product of a carboxy group is shown as a precursor compound. However, in the present invention, the precursor compound is not limited to this and may be any precursor compound obtained by esterifying any of the acidic groups.
The coupling reaction at this time is, for example, “Suzuki coupling reaction” or “Still coupling reaction” described in “Chemical Chemistry Course 5th Edition” edited by The Chemical Society of Japan, Maruzen Co., Ltd., Volume 13, p92-117. Etc. or according to these. Hydrolysis can be carried out according to the method described in, for example, the Chemical Society of Japan, “Experimental Chemistry Course 5th Edition”, Maruzen Co., Ltd., Volume 16, p10-15. For example, the method synthesized in Examples described later can be mentioned.
In the present invention, the metal complex dye of the present invention can be synthesized using the ligand LA synthesized by hydrolyzing the precursor compound. Moreover, after converting into a metal complex dye using a precursor compound like Example 1 mentioned later, an ester group is hydrolyzed according to the said method, and the metal complex dye of this invention can also be synthesize | combined.

Wherein, ^{L V} represents an amino group ^(-NR 1 ^{R 2).} In formula (L1-1), Y ¹ represents a trialkyltin group, a boronic acid group, a boronic acid ester group, a halogen atom or a perfluoroalkylsulfonyloxy group.
In the formula (L1-2), Y ² represents a halogen atom or a perfluoroalkylsulfonyloxy group when Y ^{1 in} the formula (L1-1) is a trialkyltin group, a boronic acid group or a boronic ester group, When Y ^{1 in the} formula (L1-1) is a halogen atom or a perfluoroalkylsulfonyloxy group, it represents a trialkyltin group, a boronic acid group or a boronic ester group.
In Formula (L1-2) and Formula (L1-3), R represents an alkyl group, an aryl group, or a heteroaryl group.

Specific examples of the ligand LA are shown below. Moreover, the ligand LA in the metal complex dye mentioned later is also mentioned as the ligand LA. Also included are compounds in which at least one of —COOH is a carboxy group salt with respect to the ligand LA in the following specific examples and specific examples of metal complex dyes. In this compound, examples of a counter cation that forms a salt of a carboxy group include positive ions described in the following CI. Furthermore, examples of the esterified product of a terpyridine compound include compounds obtained by esterifying at least one acidic group with respect to the ligand LA in the following specific examples and specific examples of the metal complex dye. The present invention is not limited to these ligands LA, salts or esterified products thereof. In the following specific examples, Me represents methyl.

-Ligand LD-
LD is a bidentate ligand or a tridentate ligand different from the ligand LA.
This ligand LD preferably does not have an acidic group adsorbed on the surface of the semiconductor fine particles. Even if the ligand LD contains a group corresponding to an acidic group, the ligand LD is preferably not adsorbed on the surface of the semiconductor fine particles.

In the ligand LD, at least one of the coordination atoms bonded to the metal ion M is preferably an anion. “Is an anion” means that a hydrogen atom bonded to any hydrogen atom or coordination atom in the molecule can be dissociated and bonded to the metal ion M. When the metal complex dye has a ligand LD that coordinates to the metal ion M with an anion of the coordination atom together with the ligand LA, the thermal stability of the photoelectric conversion element or the dye-sensitized solar cell is improved. In addition to high photoelectric conversion efficiency, it exhibits particularly high durability.

The ligand LD is not particularly limited as long as it is a bidentate or tridentate ligand.
For example, acyloxy group, acylthio group, thioacyloxy group, thioacylthio group, acylaminooxy group, thiocarbamate group, dithiocarbamate group, thiocarbonate group, dithiocarbonate group, trithiocarbonate group, acyl group, alkylthio group, A ligand coordinated by a group selected from the group consisting of an arylthio group, an alkoxy group and an aryloxy group, for example, a coordinate coordinated by a group in which two or three groups selected from the above group are linked to each other A child.
Other examples include ligands such as 1,3-diketone, carbonamide, thiocarbonamide, thiourea, or quinolinol. The 1,3-diketone is not particularly limited, but preferably a 1,3-diketone having 3 to 20 carbon atoms, such as acetylacetone, trifluoroacetylacetone, trifluoroacetyltrifluoroacetone, 4-fluorobenzoyltrifluoro Acetone, dipivaloylmethane, dibenzoylmethane, 3-chloroacetylacetone and the like can be mentioned.

Furthermore, the ligand represented by a following formula (DL) is also mentioned.
Among the above ligands, a ligand represented by the following formula (DL) is preferable.

In the formula, ring D ^DL , ring E ^DL and ring F each independently represent a 5-membered or 6-membered aromatic ring. R ^a , R ^a1 and R ^a4 each independently represent a substituent having no acidic group. mb represents 0 or 1.
ma1 and ma4 each independently represents an integer of 0 to 3. ma represents an integer of 0 to 4 when mb is 0, and represents an integer of 0 to 3 when mb is 1.
Here, when each of ma, ma1, and ma4 is an integer of 2 or more, the plurality of R ^a , the plurality of R ^a1, and the plurality of R ^a4 may be the same or different and are bonded to each other to form a ring. May be. R ^a and R ^a1 , R ^a and R ^a4 may be linked to form a ring.

Examples of the 5-membered or 6-membered aromatic ring in ring D ^DL , ring E ^DL and ring F include aromatic hydrocarbon rings and aromatic hetero rings, and aromatic hetero rings are preferable. In each of the ring D ^DL , the ring E ^DL and the ring F, at least one of an aromatic ring and an aliphatic hydrocarbon ring may be condensed.
When Ring D ^DL , Ring E ^DL and Ring F are aromatic hydrocarbon rings, a benzene ring is preferred.
The aromatic heterocycle may be an aromatic ring containing the above heteroatoms as ring-constituting atoms. For example, a non-condensed 6-membered ring, a 5-membered condensed 6-membered ring, or a benzene ring condensed A 5-membered ring or a 6-membered ring condensed with a benzene ring is preferable, a 6-membered ring with non-condensed ring is more preferable, and a 6-membered ring with 5-membered ring condensed is more preferable, and a 6-membered ring with non-condensed ring is more preferable.

Examples of such an aromatic heterocycle include 6-membered rings such as a pyridine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, a quinoline ring, and a quinazoline ring. In addition, pyrrole ring, imidazole ring, pyrazole ring, oxazole ring, thiazole ring, benzimidazole ring, benzoxazole ring, benzothiazole ring, indole ring, indazole ring, triazole ring, thiophene ring, furan ring, etc. Can be mentioned.
Ring D ^DL and ring E ^DL are preferably a pyrrole ring, a pyrazole ring, an imidazole ring, a triazole ring or a benzene ring, and more preferably a pyrazole ring, a triazole ring or a benzene ring.
Ring F is preferably an aromatic heterocycle containing a nitrogen atom, more preferably a pyridine ring and a pyrimidine ring, a pyrazine ring or a triazine ring, still more preferably a pyridine ring and a pyrimidine ring, and particularly preferably a pyridine ring.

Here, the ring D ^DL , the ring E ^DL and the ring F include a coordination atom that is bonded to the metal ion M. The coordination atom is not particularly limited, but is preferably a carbon atom, a nitrogen atom, a sulfur atom, an oxygen atom or an anion of these atoms.
As an anion to bind metal ions M is not particularly limited, = C - ^- carbanion such as an ion,> N ^- nitrogen anions such as ions are preferred.

When the ring F has R ^a , the position (substitution position) to which R ^a is bonded in the ring F is not particularly limited. When the ring F is a 5-membered ring, the 3-position with respect to the ring-constituting nitrogen atom coordinated to the metal atom M is preferable. When the ring F is a 6-membered ring, the 3-position or the 4-position is preferable with respect to the ring-constituting nitrogen atom coordinated to the metal atom M, and the 4-position is more preferable.
Moreover, if the ring ^{D DL} and ring ^{E DL} each have a ^{R a1} or ^{R a4,} the ^{position R a1} or ^{R a4} is attached in each ring ^{D DL} and ring ^{E DL} is not particularly limited.

^Examples of the substituent for R ^a , R ^a1 and R ^a4 include a group selected from the substituent group T described later.
R ^a is an aromatic heterocyclic group, aromatic hydrocarbon ring group, ethenyl group, ethynyl group, halogen atom, alkyl group, amino group (alkylamino group, dialkylamino group, arylamino group, diarylamino group, among others. , N-alkyl-N-arylamino groups, etc.), alkoxy groups, aryloxy groups, alkylthio groups, arylthio groups, silyl groups are preferred, aromatic heterocyclic groups, aromatic hydrocarbon ring groups, ethenyl groups, ethynyl A group, an alkyl group, an alkoxy group or an amino group (including an alkylamino group, a dialkylamino group, an arylamino group, a diarylamino group and the like) is more preferable. A group formed by combining the above groups is also preferable.
The number of carbon atoms of each substituent that can be taken as R ^a is not particularly limited, but among the substituents that can be taken as R ^a , the same type of substituents that can be taken as R ^AA to be described later are described as R ^AA. It is preferable that it is the same as the carbon number of the substituent which can be taken. More preferably, the preferable range of the carbon number is the same. Among the substituents that can be taken as R ^a , the substituents that are not the substituents that can be taken as R ^AA described later are the same as the carbon number of each substituent in the substituent group T described later, and the preferred ranges are also the same. is there. The same applies to each substituent that can be adopted as R ^a1 or R ^a4 .

R ^a1 and R ^a4 are each an alkyl group, a cycloalkyl group, an alkenyl group (preferably ethenyl group), an alkynyl group (preferably ethynyl group), an aryl group, or a heterocyclic group (preferably an aromatic heterocyclic group). , Halogen atom, alkoxy group, alkoxycarbonyl group, cycloalkoxycarbonyl group, aryloxy group, alkylthio group, arylthio group, amino group, cyano group, alkylsulfonyl group, arylsulfonyl group, halogenated alkyl group (for example, fluoroalkyl group) ), Preferably a halogenated aryl group, more preferably a halogenated alkyl group, a halogenated aryl group, a halogen atom, a cyano group, an alkylsulfonyl group or an arylsulfonyl group, a halogenated alkyl group, a halogenated aryl group, a halogen atom, Roh group is more preferable. A group formed by combining the above groups is also preferable. The halogenated alkyl group and the halogenated aryl group will be described later.

R ^a , R ^a1 and R ^a4 each preferably have, as a substituent, a group R ^VU represented by the following formula (V ^U -1) or formula (V ^U -2), and in particular, R ^a It preferably has the following group R ^VU .

In formula (V ^U -1), T represents an oxygen atom, a sulfur atom, -NR ^CA , -C (R ^CA ) ₂ -or -Si (R ^CA ) _2- , and R ^CA is a hydrogen atom or a substituent, respectively. Represents a group. R ^AA , R ^AB and R ^AC each independently represents a hydrogen atom or a substituent, and at least one of R ^AA to R ^AC represents a substituent. At least one of R ^AA and R ^AC is preferably a substituent, and R ^AA is more preferably a substituent.
In formula (V ^U -2), R ^BA to R ^BE each independently represent a hydrogen atom or a substituent, and at least one of R ^BA , R ^BB , R ^BD and R ^BE represents a substituent.

The number of the groups R ^VU possessed by the ligand LD may be one or more, preferably 1 to 3, and more preferably 1 or 2.

In the formula (V ^U -1), T is preferably a sulfur atom. R ^CA is preferably a hydrogen atom. The substituents can take as R ^CA include groups selected from Substituent Group T described later.

The substituent that can be adopted as R ^AA is not particularly limited, and examples thereof include a group selected from substituent group T described later. Preferably, alkyl group, alkenyl group (preferably ethenyl group), alkynyl group (preferably ethynyl group), cycloalkyl group, alkoxy group, cycloalkoxy group, aryloxy group, alkylthio group, cycloalkylthio group, arylthio group, amino group A group, an alkylamino group, a cycloalkylamino group, an arylamino group, a heterocyclic amino group, a silyl group or a silyloxy group.
Among the above groups, the substituent that can be taken as R ^AA is an alkyl group, cycloalkyl group, alkoxy group, cycloalkoxy group, alkylthio group, cycloalkylthio group, amino group, alkylamino group, cycloalkylamino group, or aryl. It is more preferably an amino group, more preferably an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkoxy group, an alkylamino group, a cycloalkylamino group or an arylamino group, and an alkyl group, an alkoxy group or an alkylamino group. It is particularly preferably a group, and most preferably an alkyl group or an alkoxy group.
Any of the preferable substituents of R ^AA is preferably bonded to a thiophene ring (when T is a sulfur atom) in terms of photoelectric conversion efficiency.
The above substituent that can be taken as R ^AA may be further substituted with a group selected from the substituent group T described later.

The alkyl group includes a linear alkyl group and a branched alkyl group. The alkyl group preferably has 1 to 30 carbon atoms, more preferably 4 to 30, more preferably 5 to 26, and particularly preferably 6 to 20. Examples of the alkyl group include methyl, ethyl, n-butyl, t-butyl, n-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-decyl, 3,7-dimethyloctyl, isodecyl, s- Examples include decyl, n-dodecyl, 2-butyloctyl, n-hexadecyl, isohexadecyl, n-eicosyl, n-hexacosyl, isooctacosyl, trifluoromethyl or pentafluoroethyl.

The carbon number of the cycloalkyl group is preferably 3 to 30, more preferably 5 to 30, further preferably 6 to 26, and particularly preferably 6 to 20. Examples of the cycloalkyl group include cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. The cycloalkyl group may be condensed with a heterocycle.

The alkoxy group includes a straight-chain alkoxy group and a branched alkoxy group. The alkyl part of the alkoxy group has the same meaning as the above alkyl group, and preferred ones are also the same. Examples of the alkoxy group include methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, t-butoxy, n-pentoxy, n-hexyloxy, n-octyloxy, 2-ethylhexyloxy, 3,7- Dimethyloctyloxy, n-decyloxy, isodecyloxy, s-decyloxy, 2-butyloctyloxy, n-dodecyloxy, n-hexadecyloxy, isohexadecyloxy, n-eicosyloxy, n-hexacosyloxy or An example is isooctacosyloxy.

The cycloalkyl part of the cycloalkoxy group has the same meaning as the above cycloalkyl group, and preferred ones are also the same. Examples of the cycloalkoxy group include cyclopropyloxy, cyclopentyloxy, cyclohexyloxy, cycloheptyloxy, and cyclooctyloxy.

The aryloxy group includes a hydrocarbon ring aryloxy group in which the aryl group is an aromatic hydrocarbon ring group and a heteroaryloxy group in which the aryl group is an aromatic heterocyclic group. The aryloxy group preferably has 3 to 30 carbon atoms, more preferably 3 to 25 carbon atoms, still more preferably 3 to 20 carbon atoms, and particularly preferably 3 to 16 carbon atoms. Examples of the aryloxy group include phenoxy, naphthoxy, imidazolyloxy, benzimidazolyloxy, pyridin-4-yloxy, pyrimidinyloxy, quinazolinyloxy, purinyloxy and thiophen-3-yloxy. A thiophene ring is preferred as the heterocycle of the heteroaryloxy group.

The alkylthio group includes a linear alkylthio group and a branched alkylthio group. The alkyl part of the alkylthio group has the same meaning as the above alkyl group, and preferred ones are also the same. Examples of the alkylthio group include methylthio, ethylthio, n-propylthio, i-propylthio, n-butylthio, t-butylthio, n-pentylthio, n-hexylthio, n-octylthio, 2-ethylhexylthio, 3,7-dimethyloctyl. Mention may be made of thio, n-decylthio, isodecylthio, s-decylthio, n-dodecylthio, 2-butyloctylthio, n-hexadecylthio, isohexadecylthio, n-eicosylthio, n-hexacosylthio or isooctacosylthio.

The cycloalkyl part of the cycloalkylthio group has the same meaning as the above cycloalkyl group, and preferred ones are also the same. Examples of the cycloalkylthio group include cyclopropylthio, cyclopentylthio, cyclohexylthio, cycloheptylthio, and cyclooctylthio.

The arylthio group includes a hydrocarbon ring arylthio group in which the aryl group is an aromatic hydrocarbon ring group and a heteroarylthio group in which the aryl group is an aromatic heterocyclic group. The arylthio group preferably has 3 to 30 carbon atoms, more preferably 3 to 25 carbon atoms, still more preferably 3 to 20 carbon atoms, and particularly preferably 3 to 16 carbon atoms. Examples of the arylthio group include phenylthio, naphthylthio, imidazolylthio, benzimidazolylthio, pyridin-4-ylthio, pyrimidinylthio, quinazolinylthio, purinylthio, thiophen-3-ylthio and the like. A thiophene ring is preferred as the heterocycle of the heteroarylthio group.

The alkylamino group includes an N-alkylamino group and an N, N-dialkylamino group, and the alkyl group preferably has 1 to 30 carbon atoms, and more preferably 2 to 30 carbon atoms. Examples of the alkylamino group include ethylamino, diethylamino, 2-ethylhexylamino, bis (2-ethylhexyl) amino, and n-octadecylamino.

The cycloalkylamino group includes an N-cycloalkylamino group and an N, N-dicycloalkylamino group. The cycloalkyl part of the cycloalkylamino group has the same meaning as the above cycloalkyl group, and the preferred ones are also the same. Examples of the cycloalkylamino group include cyclopropylamino, dicyclopropylamino, N-cyclopropyl-N-ethylamino, cyclopentylamino, dicyclopentylamino, N-cyclopentyl-N-methylamino, cyclohexylamino, dicyclohexylamino, And cycloheptylamino or cyclooctylamino.

The arylamino group includes a hydrocarbon ring arylamino group in which the aryl group is an aromatic hydrocarbon ring group and a heteroarylamino group in which the aryl group is an aromatic heterocyclic group. The hydrocarbon ring system arylamino group includes an N-arylamino group, an N-alkyl-N-arylamino group, and an N, N-diarylamino group. The heteroarylamino group includes an N-heteroarylamino group, an N-alkyl-N-heteroarylamino group, an N-aryl-N-heteroarylamino group and an N, N-diheteroarylamino group.
The number of carbon atoms of the arylamino group is preferably 3 to 30, more preferably 3 to 25, still more preferably 3 to 20, and particularly preferably 3 to 16. Examples of the arylamino group include phenylamino, N-phenyl-N-ethylamino, naphthylamino, imidazolylamino, benzimidazolylamino, pyridin-4-ylamino, pyrimidinylamino, quinazolinylamino, purinylamino, and thiophene-3- Ilamino and the like can be mentioned.

The heterocyclic amino group is a heterocyclic amino group (aliphatic heterocyclic amino group) other than a heteroarylamino group. The carbon number is preferably 0 to 30, more preferably 1 to 25, still more preferably 2 to 20, and particularly preferably 2 to 16. Further, as the heterocycle, those in which the ring-forming heteroatom is selected from an oxygen atom, a sulfur atom, and a nitrogen atom are preferable, and the number of ring members is preferably a 5 to 7 membered ring, and more preferably a 5 or 6 membered ring. Examples of the heterocyclic amino group include pyrrolidin-3-ylamino, imidazolidinylamino, benzimidazolidinylamino, piperidin-4-ylamino, and tetrahydrothiophen-3-ylamino.

The silyl group includes an alkylsilyl group, a cycloalkylsilyl group, an arylsilyl group, an alkyloxysilyl group, a cycloalkyloxysilyl group, and an aryloxysilyl group. Preferred silyl groups are alkylsilyl groups, cycloalkylsilyl groups, or arylsilyl groups. The carbon number of the silyl group is preferably 3 to 30, more preferably 3 to 24, still more preferably 3 to 20, and particularly preferably 3 to 18. Examples of the silyl group include trimethylsilyl, triethylsilyl, t-butyldimethylsilyl, cyclohexyldimethylsilyl, triisopropylsilyl, t-butyldiphenylsilyl, methyldimethoxysilyl, phenyldimethoxysilyl, and phenoxydimethylsilyl.

The silyloxy group includes an alkylsilyloxy group, a cycloalkylsilyloxy group, and an arylsilyloxy group. The carbon number of the silyloxy group is preferably 3 to 30, more preferably 3 to 24, still more preferably 3 to 20, and particularly preferably 3 to 18. Examples of the silyloxy group include trimethylsilyloxy, triethylsilyloxy, t-butyldimethylsilyloxy, triisopropylsilyloxy, cyclohexyldimethylsilyloxy, and t-butyldiphenylsilyloxy.

R ^AB represents a hydrogen atom or a substituent, and is preferably a hydrogen atom.
R ^AC represents a hydrogen atom or a substituent.
The substituent which can be taken as R ^AB and R ^AC has the same meaning as R ^AA , and preferred ones are also the same. When R ^AB or R ^AC is a substituent, each substituent of R ^AA to R ^AC may be the same as or different from each other.

In the group R ^VU represented by the formula (V ^U -2), R ^BA to R ^BE each independently represents a hydrogen atom or a substituent. The substituents that can be adopted by each of R ^BA to R ^BE are the same as R ^AA described above, and preferred ones are also the same.
However, at least one of R ^BA , R ^BB , R ^BD and R ^BE is a substituent. At least one or both of R ^BA and R ^BE are substituents, and R ^BB , R ^BC and R ^BD are all hydrogen atoms, or at least one or both of R ^BB and R ^BD are substituents, and R ^BA , R ^BC and R ^BE are particularly preferably all hydrogen atoms.
When two or more of R ^BA to R ^BE are substituents, the two or more substituents may be the same as or different from each other.

In the formula (DL), ma, ma1 and ma4 are preferably integers of 0 to 2, more preferably 1 or 2.

The ligand represented by the above formula (DL) is preferably represented by the following formula (DL-1) or (DL-2).

R ^a2 and R ^a3 each independently represent a substituent having no acidic group. ma2 represents 0 or 1, and 1 is preferable. ma3 represents an integer of 0-2. ma3 is more preferably 1 or 2.
X1 and X2 each independently represent CR ^a5 or a nitrogen atom. R ^a5 represents a hydrogen atom or a substituent. This substituent is synonymous with ^Ra in Formula (DL), and its preferable range is also the same. The ring containing X1 and X2 (also referred to as ring F) has the same meaning as ring F in formula (DL), and the preferred range is also the same.
R ^a1, ^R a4, ma1 and ma4 has the same meaning as ^R ^a1, R a4, ma1 and ma4 in the formula (DL), and the preferred range is also the same.
The substituent represented by R ^a2 and R ^a3 has the same meaning as R ^a in the above formula (DL), and the preferred range is also the same.
When each of ma1, ma3 and ma4 is an integer of 2 or more, the plurality of R ^a1 , R ^a3 and R ^a4 may be the same or different, and may be bonded to each other to form a ring.

Ring D and ring E each independently represent a 5-membered or 6-membered aromatic ring. Examples of such an aromatic ring include the rings mentioned in the ring DD ^L and ring E ^DL in the above formula (DL), and preferred aromatic rings are the same as those mentioned in the ring D ^DL and ring E ^DL. .
The bond between D ¹ and D ^{2 in} ring D and ring E and the carbon atom bonded to the F ring may be a single bond or a double bond.
D ¹ and D ² each independently represents an anion of a carbon atom or an anion of a nitrogen atom.

Ring D and ring E are preferably a pyrrole ring, an imidazole ring, a pyrazole ring, a triazole ring or a benzene ring, and more preferably a pyrazole ring, a triazole ring or a benzene ring.

When the ligand LD is a bidentate ligand, a bidentate ligand represented by any one of the following formulas (2L-1) to (2L-4) is preferable.

In the formula, * represents a coordination position (bonding position) with the metal ion M. Ring D ^2L represents an aromatic ring. A ¹¹¹ to A ¹⁴¹ each independently represents an anion of a nitrogen atom or an anion of a carbon atom. R ¹¹¹ to R ¹⁴³ each independently represents a hydrogen atom or a substituent having no acidic group.

Here, A ¹¹¹ to A ¹⁴¹ are an anion of a carbon atom or an anion of a nitrogen atom in which a hydrogen atom bonded to a nitrogen atom or a carbon atom constituting the ring D ^2L is dissociated. In the formulas (2L-1) to (2L-4), the ring D ^2L is an aromatic hydrocarbon ring, an aromatic heterocycle containing oxygen, an aromatic heterocycle containing sulfur, or an aromatic heterocycle containing nitrogen Is mentioned.
Examples of the aromatic hydrocarbon ring include a benzene ring and a naphthalene ring, and a benzene ring is preferable, and a benzene ring substituted with a halogen atom, a halogenated alkyl group, or a halogenated aryl group is more preferable. The halogenated alkyl group is an alkyl group substituted with a halogen atom, and a fluorinated alkyl group (for example, a trifluoromethyl group) is preferable. The halogenated aryl group is preferably a phenyl group substituted with 1 to 5 halogen atoms.
The aromatic heterocycle containing oxygen is preferably a furan ring, and the aromatic heterocycle containing sulfur is preferably a thiophene ring. As the aromatic heterocycle containing nitrogen, a pyrrole ring, a pyrazole ring, an imidazole ring and a triazole ring are preferable.
Ring D ^2L is, for example, each ring in which one of the ring constituent atoms of a benzene ring, thiophene ring or furan ring is an anion, or the following formulas (a-1) to (a-5), (a-1a) , (A-2a), (a-1b) and each ring represented by (a-4a) are preferred.

In the formula, Rd represents a substituent having no acidic group. b1 represents an integer of 0 to 2, b2 represents an integer of 0 to 3, and b3 represents 0 or 1. When b1 is 2 or b2 is 2 or more, a plurality of Rd may be the same or different. A plurality of Rd's may be bonded to each other to form a ring. Examples of Rd include a group selected from the substituent group T described later.

In the formula, Rd and b1 to b3 are synonymous with Rd and b1 to b3 in the above formulas (a-1) to (a-5), 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 the 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, cycloalkyl group, alkenyl group, fluoroalkyl group, aryl group, halogen atom, alkoxycarbonyl group, cycloalkoxycarbonyl group, cyano group, alkylsulfonyl group, arylsulfonyl group and A group formed by combining these, more preferably a linear or branched alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, and a group formed by combining these, more preferably a linear or branched alkyl halide. Group, a halogenated aryl group.

The substituent represented by R ¹¹¹ to R ¹⁴³ has the same meaning as R ^a in the above formula (DL), and the preferred range is also the same.
At least one of R ¹¹¹ to R ¹¹⁴ , at least one of R ¹²¹ to R ¹²³ , at least one of R ¹³¹ to R ¹³³ , and at least one of R ¹⁴¹ to R ¹⁴³ are preferably substituents, and one Or it is more preferable that two are substituents.

When the ligand LD is a tridentate ligand, a tridentate ligand represented by any one of the following formulas (3L-1) to (3L-4) is preferable.

In the formula, * represents a coordination position (bonding position) with the metal ion M. Ring D ^2L represents an aromatic ring. A ²¹¹ to A ²⁴² each independently represents a nitrogen atom or a carbon atom. However, at least one of A ²¹¹ and A ²¹² , A ²²¹ and A ²²² , A ²³¹ and A ²³² , and A ²⁴¹ and A ²⁴² is an anion. R ²¹¹ to R ²⁴¹ each independently represents a hydrogen atom or a substituent having no acidic group.

Of A ²¹¹ to A ^242, an anion is synonymous with A ¹¹¹ to A ^{141 in} the above formulas (2L-1) to (2L-4). A ²¹¹ to A ²⁴² having no anion is a nitrogen atom having no hydrogen atom.
Ring D ^2L in formulas (3L-1) to (3L-4) has the same meaning as ring D ^{2L in} formulas (2L-1) to (2L-4), and the preferred range is also the same. Ring D ^2L is more preferably an aromatic ring containing any one of A ²¹¹ to A ^{242 and} a carbon atom or two carbon atoms. At this time, in each formula, two rings ^D2L may be the same or different.
The substituents represented by R ²¹¹ to R ²⁴¹ each have the same meaning as R ^a in the above formula (DL), and the preferred range is also the same.
At least one of R ²¹¹ to R ²¹³ , at least one of R ²²¹ and R ²²² , at least one of R ²³¹ and R ²³² , and R ²⁴¹ are preferably substituents.

In the present invention, among the bidentate or tridentate ligands in the ligand LD, the atom coordinated to the metal ion M is a nitrogen anion or a carbon anion, and the substituent is a (hetero) arylamino group or divalent. Those having a (hetero) arylamino group are particularly preferred because the absorption becomes longer.
Specifically, the preferable ligand described above is a ligand in which at least one of the atoms coordinated to the metal ion M is a nitrogen anion or a carbon anion, and the partial structure has the following formula (SA): .

In the formula, R ^DA1 represents an aryl group or a heteroaryl group, and R ^DA2 represents an alkyl group, an aryl group, or a heteroaryl group. R ^DA1 and R ^DA2 may be bonded to each other to form a ring. LL represents an ethenyl group, an ethynyl group, an arylene group, or a heteroarylene group. a represents an integer of 0 to 5, and when a is 2 or more, a plurality of LLs may be the same or different.

The group represented by the formula (SA) is preferably substituted with an aromatic hydrocarbon ring coordinated to the metal ion M or an aromatic heterocycle containing nitrogen, and the aromatic heterocycle containing a nitrogen atom More preferably, it is substituted.
Of the groups represented by the formula (SA), at least one of R ^DA1 and R ^DA2 is preferably an aryl group or a heteroaryl group, and more preferably an aryl group. The alkyl group, aryl group, and heteroaryl group may have a substituent, and examples of such a substituent include a group selected from the substituent group T described later.
Although it does not specifically limit as an aryl group, A phenyl group, a naphthyl group, etc. are mentioned, A phenyl group is preferable. Although it does not specifically limit as a heteroaryl group, A furanyl group and a thienyl group are preferable.

LL may form a condensed ring structure together with an aromatic hydrocarbon ring or a nitrogen-containing aromatic heterocycle containing a ligand coordination atom. For example, LL may be an ethenyl group, and this ethenyl group may be bonded to a nitrogen-containing aromatic heterocycle containing a ligand coordination atom to form a quinoline ring.
Examples of the arylene group in LL include a phenylene group and a naphthylene group, and the heteroarylene group is preferably a divalent 5- or 6-membered ring containing an oxygen atom, a sulfur atom, or a nitrogen atom as a ring-constituting atom. And may be condensed with a benzene ring or a hetero ring.
Examples of the hetero ring of the heteroarylene group include a furan ring, a thiophene ring, a pyrrole ring, and a pyridine ring, and a furan ring and a thiophene ring are preferable.

The ethenyl group, arylene group, and heteroarylene group in LL may have a substituent, and examples of the substituent include a group selected from the substituent group T described later.

In the above formula (SA), it is preferable that a is 0, or a is 1 and LL is an ethenyl group, ethynyl group, phenylene group or heteroarylene group, and a is 0 or a is 1 and phenylene. Or a heteroarylene group, more preferably a is 0, or a is 1, a phenylene group, a divalent furan ring group, or a divalent thiophene ring group, and a is 0. It is particularly preferred.

In the present invention, those in which R ^DA1 and R ^DA2 are bonded to each other to form a ring are also preferred.
The ring to be formed is preferably a 5- or 6-membered ring, and more preferably bonded when R ^DA1 and R ^DA2 are both aryl groups.
The ring formed by combining R ^DA1 and R ^DA2 with each other is preferably the following ring.

Here, R ^DA3 and R ^DA4 each independently represents an alkyl group.
The ring may have a substituent, and examples of such a substituent include a group selected from the substituent group T described later.

The ligand represented by the above formula (DL) is disclosed in US Patent Application Publication No. 2010 / 0258175A1, Japanese Patent No. 4298799, Angew. Chem. Int. Ed. 2011, 50, p. It can be synthesized by the method described in 2054-2058, the method described in the references cited in this document, or a method according to these methods.

Specific examples of the ligand represented by the above formula (DL) are shown below. Moreover, the ligand LD in the metal complex pigment | dye mentioned later as this ligand LD is also mentioned. The present invention is not limited to these ligands LD. In the following specific examples, Me represents methyl, and * represents a bonding position at which the rings or the pyridine ring and the substituent R ²⁰¹ are bonded to each other.

-Ligand LX-
The ligand LX may be a monodentate ligand, and is an acyloxy group, acylthio group, thioacyloxy group, thioacylthio group, acylaminooxy group, thiocarbamate group, dithiocarbamate group, thiocarbonate group, dithiocarbonate. A group selected from the group consisting of a group, trithiocarbonate group, acyl group, thiocyanate group, isothiocyanate group, cyanate group, isocyanate group, cyano group, alkylthio group, arylthio group, alkoxy group, aryloxy group and halogen atom, or Atoms or their anions are preferred.
When the ligand LX contains an alkyl group, an alkenyl group, an alkynyl group, an alkylene group, etc., they may or may not have a substituent. Moreover, when an aryl group, a heterocyclic group, a cycloalkyl group, etc. are included, they may or may not have a substituent, and may be monocyclic or condensed.

Among them, the ligand LX is preferably a cyanate group, an isocyanate group, a thiocyanate group and an isothiocyanate group or anions thereof, more preferably an isocyanate group (isocyanate anion) or an isothiocyanate (NCS) group (isothiocyanate anion), An isothiocyanate group (isothiocyanate anion) is particularly preferred.

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

When the counter ion CI is a positive counter ion, for example, the counter ion CI 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 (Li ion, Na ion, K ion, etc.), alkaline earth metal ions, metal complex ions or protons. As the positive counter ion, inorganic or organic ammonium ions (tetraethylammonium ion, tetrabutylammonium ion, tetrahexylammonium ion, tetraoctylammonium ion, tetradecylammonium ion, etc.), alkali metal ions, and protons are preferable.

When the counter ion CI is a negative counter ion, for example, the counter ion CI may be an inorganic anion or an organic anion. For example, hydroxide ion, halogen anion (for example, fluoride ion, chloride ion, bromide ion, iodide ion, etc.), substituted or unsubstituted alkylcarboxylate ion (acetate ion, trifluoroacetate ion, etc.), Substituted or unsubstituted arylcarboxylate ions (benzoate ions, etc.), substituted or unsubstituted alkylsulfonate ions (methanesulfonate ions, trifluoromethanesulfonate ions, etc.), substituted or unsubstituted arylsulfonate ions (for example, p-toluenesulfonate ion, p-chlorobenzenesulfonate ion, etc.), aryl disulfonate ion (eg, 1,3-benzenedisulfonate ion, 1,5-naphthalenedisulfonate ion, 2,6-naphthalenedisulfonate ion, etc.) , Alkyl sulfate ion Such as methyl sulfate ion, etc.), sulfate ion, thiocyanate ion, perchlorate ion, tetrafluoroborate ion, hexafluorophosphate ion, and a picrate ion. Furthermore, an ionic polymer or another dye having a charge opposite to that of the dye may be used as the charge balance counter ion, and a metal complex ion (for example, bisbenzene-1,2-dithiolatonickel (III)) can also be used. is there. Negative counter ions include halogen anions, substituted or unsubstituted alkyl carboxylate ions, substituted or unsubstituted alkyl sulfonate ions, substituted or unsubstituted aryl sulfonate ions, aryl disulfonate ions, perchlorate ions , Hexafluorophosphate ions are preferred, and halogen anions and hexafluorophosphate ions are more preferred.

-Metal complex dye-
The metal complex dye of the present invention is represented by the following formula (I).
In the metal complex dye represented by the formula (I), the ligand LA, the ligand LD, and the ligand LX are as described above, and the combination of these ligands is not particularly limited. A preferred combination of ligands is a combination of a preferred ligand LA, a preferred ligand LD, and a preferred ligand LX.

Formula (I) M (LA) (LD) _p (LX) _q · (CI) _z
In the formula, M, LA, LD, p, LX, q, CI and z are as described above, and preferable ones are also the same.

The metal complex dye represented by the formula (I) is preferably a metal complex dye represented by the following formula (I-1) or (I-2).

In the formula, M and LX have the same meanings as M and LX in the above formula (I).
R ¹ and ^{R 2} have the same meanings as ^{R 1} and ^{R 2} in the formula (LA-1).
Anc1 and Anc2 each independently represent an acidic group. The acidic group is synonymous with the acidic group of formula (LA-1), and preferred ones are also the same.
Ring D and ring E each independently represent a 5-membered or 6-membered aromatic ring. D ¹ and D ² each independently represents an anion of a carbon atom or an anion of a nitrogen atom. Here, the bond between D ¹ and D ² in ring D and ring E and the carbon atom bonded to the pyridine ring is a single bond or a double bond. Ring D and ring E have the same meanings as ring D and ring E in the above formulas (DL-1) and (DL-2), and preferred ones are also the same.
R ^a1 to R ^a4 each independently represents a substituent. R ^a1 ~ ^{R a4} are each the same meaning as ^R a1 ^{~ R a4} in the formula (DL-1) and (DL-2), it is preferable also the same.
ma1, ma2 and ma4 each independently represents an integer of 0 to 3. ma3 represents an integer of 0 to 4. ma1 and ma4 are synonymous with ma1 and ma4 in the above formulas (DL-1) and (DL-2), respectively, and preferred ones are also the same. The preferred range of ma2 and ma3 is the same as the preferred range of ma in the above formula (DL). When each of ma1 to ma4 represents an integer of 2 or more, the plurality of R ^a1 to R ^a4 may be bonded to each other to form a ring.

Examples of the metal complex dye represented by the formula (I) include a method described in JP2013-084594A, a method described in Japanese Patent No. 4298799, US Patent Application Publication No. 2013 / 0018189A1, and US Patent Application Publication. No. 2012 / 0073660A1, U.S. Patent Application Publication No. 2012 / 0111410A1, and U.S. Patent Application Publication No. 2010 / 0258175A1, Angew. Chem. Int. Ed. 2011, 50, p. It can be synthesized by the method described in 2054-2058, the method described in the reference cited in this document, the above-mentioned patent document relating to solar cells, a known method, or a method analogous thereto.

The metal complex dye represented by the formula (I) has a maximum absorption wavelength in a solution of preferably 300 to 1000 nm, more preferably 350 to 950 nm, and particularly preferably 370 to 900 nm. is there.

In the following description (including examples), specific examples of the metal complex dye represented by the formula (I) are shown. In addition to the following specific examples and specific examples, metal complex dyes in which at least one of —COOH is a salt of a carboxy group are also exemplified. In this metal complex dye, examples of the counter cation that forms a salt of a carboxy group include positive ions described in the above CI. The present invention is not limited to these metal complex dyes. These metal complex dyes may be any of these isomers or a mixture of these isomers when optical isomers and geometric isomers are present.
The following specific examples show the specific examples of the ligands LA, LD, and LX independently of each other regardless of the specific combinations of the ligands LA, LD, and LX in each specific example. In the specific examples, Me represents methyl and TBA represents tetrabutylammonium.

<Substituent group T>
In the present invention, preferred substituents include groups selected from the following substituent group T. The substituent group T is a substituent group that does not contain the acidic group.
In this specification, the alkyl group is stated separately and cycloalkyl groups (e.g., wherein the substituents can take as R ^AA), alkyl groups, in the sense includes straight chain alkyl groups and branched alkyl groups Use. On the other hand, when an alkyl group is not described separately from a cycloalkyl group (when simply described as an alkyl group), and unless otherwise specified, an alkyl group is a linear alkyl group or a branched alkyl group And cycloalkyl group. This is because a group containing a group that can take a cyclic structure (alkyl group, alkenyl group, alkynyl group, etc.) (alkoxy group, alkylthio group, alkenyloxy group, etc.) or a group containing a group that can take a cyclic structure (the above alkyl ester). The same applies to chemicals). In the description of the substituent group T below, for example, a straight-chain or branched structure group and a cyclic structure group are clearly described, such as an alkyl group and a cycloalkyl group. Sometimes.
In the present specification, when only described as a substituent, this substituent group T is referred to, and each group, for example, an alkyl group, is only described. The preferred ranges and specific examples in the corresponding group of the substituent group T are applied.

The group included in the substituent group T includes the following groups or groups formed by combining a plurality of the following groups.
An alkyl group (preferably having 1 to 20 carbon atoms such as methyl, ethyl, isopropyl, n-butyl, t-butyl, pentyl, hexyl, heptyl, octyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxyl. Methyl or trifluoromethyl), an alkenyl group (preferably having 2 to 20 carbon atoms such as vinyl, allyl or oleyl), an alkynyl group (preferably having 2 to 20 carbon atoms such as ethynyl, butynyl or phenylethynyl), A cycloalkyl group (preferably having 3 to 20 carbon atoms such as cyclopropyl, cyclopentyl, cyclohexyl or 4-methylcyclohexyl), a cycloalkenyl group (preferably having 5 to 20 carbon atoms such as cyclopentenyl or cyclohexenyl), aryl Group (aromatic carbonization A cyclic group, preferably having 6 to 26 carbon atoms, such as phenyl, 1-naphthyl, 4-methoxyphenyl, 2-chlorophenyl, 3-methylphenyl, difluorophenyl or tetrafluorophenyl), a heterocyclic group (preferably carbon It is more preferably a 5-membered or 6-membered heterocyclic group having at least one oxygen atom, sulfur atom, or nitrogen atom and having an aromatic ring and an aliphatic ring. Examples of the heterocyclic group (eg, heteroaryl group) include the following groups, such as 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl or 2-oxazolyl), an alkoxy group (preferably a carbon A number of 1 to 20, for example, methoxy, ethoxy, isopropyloxy or benzyloxy), alkene A ruoxy group (preferably having 2 to 20 carbon atoms, such as vinyloxy or allyloxy), an alkynyloxy group (preferably having 2 to 20 carbon atoms, such as 2-propynyloxy or 4-butynyloxy), a cycloalkyloxy group (preferably Has 3 to 20 carbon atoms, such as cyclopropyloxy, cyclopentyloxy, cyclohexyloxy or 4-methylcyclohexyloxy), an aryloxy group (preferably having 6 to 26 carbon atoms, such as phenoxy, 1-naphthyloxy, 3 -Methylphenoxy or 4-methoxyphenoxy), a heterocyclic oxy group (eg imidazolyloxy, benzimidazolyloxy, thiazolyloxy, benzothiazolyloxy, triazinyloxy or purinyloxy),

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

An acylamino group (preferably an acylamino group having 1 to 20 carbon atoms, such as acetylamino, cyclohexylcarbonylamino or benzoylamino), a sulfonamide group (preferably an alkyl, cycloalkyl or aryl sulfonamide group having 0 to 20 carbon atoms) For example, methanesulfonamide, benzenesulfonamide, N-methylmethanesulfonamide, N-cyclohexylsulfonamide or N-ethylbenzenesulfonamide), an alkylthio group (preferably having 1 to 20 carbon atoms, for example, methylthio, ethylthio , Isopropylthio or benzylthio), a cycloalkylthio group (preferably having 3 to 20 carbon atoms, such as cyclopropylthio, cyclopentylthio, cyclohexylthio or 4-methylcyclo Xylthio), arylthio groups (preferably having 6 to 26 carbon atoms, such as phenylthio, 1-naphthylthio, 3-methylphenylthio or 4-methoxyphenylthio), alkyl, cycloalkyl or arylsulfonyl groups (preferably having 1 carbon atom) -20, for example methylsulfonyl, ethylsulfonyl, cyclohexylsulfonyl or benzenesulfonyl),

A silyl group (preferably a silyl group having 1 to 20 carbon atoms and substituted with alkyl, aryl, alkoxy and aryloxy is preferable, for example, trimethylsilyl, triethylsilyl, triisopropylsilyl, triphenylsilyl, diethylbenzylsilyl or dimethylphenylsilyl. ), A silyloxy group (preferably a silyloxy group having 1 to 20 carbon atoms and substituted with alkyl, aryl, alkoxy and aryloxy, such as triethylsilyloxy, triphenylsilyloxy, diethylbenzylsilyloxy or dimethylphenylsilyloxy ), A hydroxy group, a cyano group, a nitro group, or a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom or an iodine atom).

The group selected from the substituent group T is more preferably an alkyl group, alkenyl group, cycloalkyl group, aryl group, heterocyclic group, alkoxy group, cycloalkoxy group, aryloxy group, alkylthio group, cycloalkylthio group, arylthio group. , Alkoxycarbonyl group, cycloalkoxycarbonyl group, amino group, acylamino group, cyano group or halogen atom, particularly preferably alkyl group, alkenyl group, heterocyclic group, alkoxy group, alkylthio group, alkoxycarbonyl group, amino group, An acylamino group or a cyano group is mentioned.

When a compound or a substituent includes an alkyl group, an alkenyl group, etc., these 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.

Next, preferred modes of main members of the photoelectric conversion element and the dye-sensitized solar cell will be described with reference to FIGS. 1 and 2.

<Conductive support>
The conductive support is not particularly limited as long as it has conductivity and can support the photoreceptor layer 2 and the like. The conductive support includes the conductive support 1 made of a conductive material, for example, a metal, or a glass or plastic substrate 44 and a transparent conductive film 43 formed on the surface of the substrate 44. A conductive support 41 is preferred.

Among these, the conductive support 41 in which a conductive metal oxide is coated on the surface of the substrate 44 to form a transparent conductive film 43 is more preferable. Examples of the substrate 44 made of plastic include a transparent polymer film described in paragraph No. 0153 of JP-A-2001-291534. In addition to glass and plastic, ceramic (Japanese Patent Laid-Open No. 2005-135902) or conductive resin (Japanese Patent Laid-Open No. 2001-160425) can be used as a material for forming the substrate 44. As the metal oxide, tin oxide (TO) is preferable, and fluorine-doped tin oxide such as indium-tin oxide (tin-doped indium oxide; ITO) and fluorine-doped tin oxide (FTO) is particularly preferable. The coating amount of the metal oxide at this time is preferably 0.1 to 100 g per 1 m ² of the surface area of the substrate 44. When the conductive support 41 is used, light is preferably incident from the substrate 44 side.

Conductive supports 1 and 41 are preferably substantially transparent. “Substantially transparent” means that the transmittance of light (wavelength 300 to 1200 nm) is 10% or more, preferably 50% or more, and particularly preferably 80% or more. .
The thickness of the conductive supports 1 and 41 is not particularly limited, but is preferably 0.05 μm to 10 mm, more preferably 0.1 μm to 5 mm, and particularly preferably 0.3 μm to 4 mm. .
When the transparent conductive film 43 is provided, the thickness of the transparent conductive film 43 is preferably 0.01 to 30 μm, more preferably 0.03 to 25 μm, and particularly preferably 0.05 to 20 μm. .

The conductive supports 1 and 41 may have a light management function on the surface. 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 may be provided on the surface, as described in JP-A-2002-260746. The light guide function may be provided.

<Photoreceptor layer>
Other configurations are not particularly limited as long as the photoreceptor layer includes the semiconductor fine particles 22 on which the dye 21 is supported and an electrolyte. Preferably, the photoreceptor layer 2 and the photoreceptor layer 42 are used.

-Semiconductor fine particles (layers formed by semiconductor fine particles)-
The semiconductor fine particles 22 are preferably fine particles of a metal chalcogenide (eg, oxide, sulfide, selenide, etc.) or a compound having a perovskite crystal structure. Preferred examples of the metal chalcogenide include titanium, tin, zinc, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium or tantalum oxide, cadmium sulfide, and cadmium selenide. Preferred examples of the compound having a perovskite crystal structure include strontium titanate and calcium titanate. Of these, titanium oxide (titania), zinc oxide, tin oxide, and tungsten oxide are particularly preferable.

Examples of the crystal structure of titania include anatase type, brookite type, and rutile type, and anatase type and brookite type are preferable. Titania nanotubes, nanowires, and nanorods can be used alone or mixed with titania fine particles.

The particle diameters of the semiconductor fine particles 22 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. Is preferred. Examples of a method for coating the semiconductor fine particles 22 on the conductive support 1 or 41 include a wet method, a dry method, and other methods.

The semiconductor fine particles 22 preferably have a large surface area so that a large amount of the dye 21 can be adsorbed. For example, in a state where the semiconductor fine particles 22 are coated on the conductive support 1 or 41, the surface area thereof 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 larger the thickness of the semiconductor layer 45 (synonymous with the photoreceptor layer 2 in the photoelectric conversion element 10) formed by the semiconductor fine particles 22, the greater the amount of the dye 21 that can be carried per unit area, and the higher the light absorption efficiency. However, since the diffusion distance of the generated electrons increases, the loss due to charge recombination also increases.

The preferred thickness of the semiconductor layer 45 (photosensitive layer 2 in the photoelectric conversion element 10) is not uniquely determined depending on the use of the photoelectric conversion element, but is typically 0.1 to 100 μm. When used as a dye-sensitized solar cell, the thickness is more preferably 1 to 50 μm, further preferably 3 to 30 μm.

The semiconductor fine particles 22 are preferably applied to the conductive support 1 or 41 and then baked at a temperature of 100 to 800 ° C. for 10 minutes to 10 hours to bring the particles into close contact with each other. The film forming temperature is preferably 60 to 600 ° C. when glass is used as the material of the conductive support 1 or the substrate 44.

The coating amount of the semiconductor fine particles 22 per 1 m ² of the surface area of the conductive support 1 or 41 is preferably 0.5 to 500 g, more preferably 5 to 100 g.

Between the conductive support 1 or 41 and the photoreceptor layer 2 or 42, in order to prevent reverse current due to direct contact between the electrolyte contained in the photoreceptor layer 2 or 42 and the conductive support 1 or 41, It is preferable to form a short-circuit prevention layer.
In order to prevent contact between the

light receiving electrode

5 or 40 and the

counter electrode

4 or 48, it is preferable to use a spacer S (see FIG. 2) or a separator.

-Dye-
In the photoelectric conversion element 10 and the dye-sensitized solar cell 20, at least one metal complex dye represented by the above formula (I) is used as a sensitizing dye. The metal complex dye represented by the formula (I) is as described above.

In the present invention, examples of the dye that can be used in combination with the metal complex dye of the above formula (I) include a Ru complex dye, a squarylium cyanine dye, an organic dye, a porphyrin dye, and a phthalocyanine dye.

Examples of the Ru complex dye include Ru complex dyes described in JP-A-7-500630 (especially synthesized in Examples 1 to 19 on page 5, lower left column, line 5 to page 7, upper right column, line 7). Dyes), Ru complex dyes described in JP-T-2002-512729 (especially dyes synthesized in Examples 1 to 16 on the third line to the 29th line from the bottom of page 20), JP, Ru complex dyes described in JP 2001-59062 (particularly dyes described in paragraphs 0087 to 0104), Ru complex dyes described in JP 2001-6760 A (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 paragraph No. 0005) Described), Ru complex dyes described in International Publication No. 2007/91525 (especially dyes described in [0067]), Ru complex dyes described in Japanese Patent Application Laid-Open No. 2001-291534 (particularly, paragraphs 0120 to 0144), Ru complex dyes described in JP2012-012570 (especially dyes described in paragraphs 0095 to 0103), Ru metal complex dyes described in JP2013-084594A (especially And dyes described in paragraphs 0072 to 0081), Ru complex dyes described in International Publication No. 2013/088888 (particularly, dyes described in [0286] to [0293]), or International Publication Nos. 2013/47615. Ru complex dyes described in the above (especially dyes described in [0078] to [0082]).

Examples of the squarylium cyanine dye include squarylium cyanine dyes described in JP-A No. 11-214730 (particularly dyes described in paragraphs 0036 to 0047), squarylium cyanine dyes described in JP-A No. 2012-144688 (in particular, And dyes described in paragraphs 0039 to 0046 and 0054 to 0060), or squarylium cyanine dyes described in JP 2012-84503 A (in particular, dyes described in paragraphs 0066 to 0076 and the like). .

Examples of the organic dye include organic dyes described in JP-A No. 2004-063274 (particularly dyes described in paragraph Nos. 0017 to 0021) and organic dyes described in JP-A No. 2005-123033 (particularly paragraph numbers). Dyes described in JP-A-2007-287694, organic dyes described in JP-A No. 2007-287694 (especially dyes described in paragraphs 0091-0096), organic dyes described in JP-A-2008-71648 (in particular, And the organic dyes described in International Publication No. 2007/119525 (particularly, the dyes described in [0024]).

Examples of porphyrin dyes include Angew. Chem. Int. Ed. 49, p. 1-5 (2010), and the like. Examples of the phthalocyanine dye include Angew. Chem. Int. Ed. 46, p. 8358 (2007) and the like.

The dye that can be used in combination is preferably a Ru complex dye, a squarylium cyanine dye, or an organic dye.

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 surface area of the conductive support 1 or 41. is there. The amount of the dye 21 adsorbed on the semiconductor fine particles 22 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 22. By using such a dye amount, the sensitizing effect in the semiconductor fine particles 22 can be sufficiently obtained.
The metal complex dye of the present invention can exhibit excellent photoelectric conversion efficiency in the photoelectric conversion element and the dye-sensitized solar cell even when the adsorption amount is particularly small in the above-described range of the adsorption amount.

When the metal complex dye represented by the formula (I) and another dye are used in combination, the ratio of the mass of the metal complex dye represented by the formula (I) / the mass of the other dye is 95/5 to 10/90. Is preferred, 95/5 to 50/50 is more preferred, 95/5 to 60/40 is more preferred, 95/5 to 65/35 is particularly preferred, and 95/5 to 70/30 is most preferred.

After the dye is supported on the semiconductor fine particles 22, the surface of the semiconductor fine particles 22 may be treated with an amine compound. Preferable amine compounds include pyridine compounds (for example, 4-t-butylpyridine, polyvinylpyridine) and the like. In the case of a liquid, these may be used as they are, or may be used after being dissolved in an organic solvent.

-Coadsorbent-
In the present invention, it is preferable to use a coadsorbent together with the metal complex dye represented by the formula (I) or a dye used in combination as necessary. As such a co-adsorbent, a co-adsorbent having at least one acidic group (preferably, a carboxy group or a salt thereof) is preferable, and examples thereof include a compound having a fatty acid or a steroid skeleton.
The fatty acid may be a saturated fatty acid or an unsaturated fatty acid, and examples thereof include butanoic acid, hexanoic acid, octanoic acid, decanoic acid, hexadecanoic acid, dodecanoic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid. .
Examples of the compound having a steroid skeleton include cholic acid, glycocholic acid, chenodeoxycholic acid, hyocholic acid, deoxycholic acid, lithocholic acid, ursodeoxycholic acid and the like. Preferred are cholic acid, deoxycholic acid, and chenodeoxycholic acid, and more preferred is cholic 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.
The acidic group is synonymous with the acidic group in the above formula (LA-1), and the preferred range is also the same.
Among these, R ^A1 is preferably a carboxy group, a sulfo group, or an alkyl group substituted by a salt thereof, —CH (CH ₃ ) CH ₂ CH ₂ CO ₂ H, —CH (CH ₃ ) CH ₂ CH _2. More preferred is CONHCH ₂ CH ₂ SO ₃ H.

Examples of R ^A2 include a group selected from the above substituent group T. Of these, an alkyl group, a hydroxy group, an acyloxy group, an alkylaminocarbonyloxy group or an arylaminocarbonyloxy group is preferable, and an alkyl group, a hydroxy group or an acyloxy group is more preferable.
nA is preferably 2 to 4.

The co-adsorbent has an effect of suppressing inefficient association of the metal complex dye by adsorbing to the semiconductor fine particles 22 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 the co-adsorbent used is not particularly limited, but from the viewpoint of effectively expressing the above action, it is preferably 1 to 200 mol, more preferably 10 to 150 mol, relative to 1 mol of the metal complex dye. Particularly preferred is 20 to 50 mol.

-Light scattering layer-
In the present invention, the light scattering layer is different from the semiconductor layer in that it has a function of scattering incident light.
In the dye-sensitized solar cell 20, the light scattering layer 46 preferably contains rod-like or plate-like metal oxide particles. Examples of the metal oxide particles used in the light scattering layer 46 include the metal chalcogenide (oxide) particles. When the light scattering layer 46 is provided, the thickness of the light scattering layer is preferably 10 to 50% of the thickness of the photoreceptor layer 42.
The light scattering layer 46 is preferably a light scattering layer described in JP-A No. 2002-289274, and the description of JP-A No. 2002-289274 is preferably incorporated in the present specification as it is.

<Charge transfer layer>
The charge transfer body layers 3 and 47 used in the photoelectric conversion element of the present invention are layers having a function of replenishing electrons to the oxidant of the dye 21 and are provided between the

light receiving electrode

5 or 40 and the

counter electrode

4 or 48. It is done.
The

charge transfer layer

3 and 47 contains an electrolyte. Here, “the charge transfer layer contains an electrolyte” means to include both modes of the mode in which the charge transfer layer is made of only an electrolyte and the mode containing an electrolyte and a substance other than the electrolyte.
The charge transfer body layers 3 and 47 may be solid, liquid, gel, or a mixed state thereof.

- Electrolytes -
Examples of the electrolyte include a liquid electrolyte in which a redox couple is dissolved in an organic solvent, a molten salt containing a redox couple, and a so-called gel electrolyte in which a polymer matrix is impregnated with a liquid in which a redox couple is dissolved in an organic solvent. . Especially, a liquid electrolyte is preferable at the point of photoelectric conversion efficiency.

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) A combination of an alkyl viologen (eg, methyl viologen chloride, hexyl viologen bromide, benzyl viologen tetrafluoroborate) and a reduced form thereof, a combination of polyhydroxybenzene (eg, hydroquinone, naphthohydroquinone, etc.) and an oxidized form thereof, A combination of trivalent iron complexes (for example, a combination of red blood salt and yellow blood salt), a combination of divalent and trivalent cobalt complexes, and the like. Among these, a combination of iodine and iodide or a combination of divalent and trivalent cobalt complexes is preferable, and a combination of iodine and iodide is particularly preferable.

The cobalt complex is preferably a complex represented by the formula (CC) described in paragraphs 0144 to 0156 of JP2014-82189A, and described in paragraphs 0144 to 0156 of JP2014-82189A. It is preferably incorporated in the present specification as it is.

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.

The organic solvent used for the liquid electrolyte and the gel electrolyte is not particularly limited, but an aprotic polar solvent (for example, acetonitrile, propylene carbonate, ethylene carbonate, dimethylformamide, dimethyl sulfoxide, sulfolane, 1,3-dimethylimidazolinone, 3 -Methyloxazolidinone etc.) are preferred.
In particular, the organic solvent used for the liquid electrolyte is preferably a nitrile compound, an ether compound, an ester compound, more preferably a nitrile compound, and particularly preferably acetonitrile or methoxypropionitrile.

Molten salts include ionic liquids containing imidazolium or triazolium cations, ionic liquids containing oxazolium cations, ionic liquids containing pyridinium cations, ionic liquids containing guanidinium cations, and these A combination is preferred. Moreover, you may combine a specific anion with respect to these cations. Additives may be added to these molten salts. The molten salt may have a liquid crystalline substituent. Moreover, the molten salt of a quaternary ammonium salt can also be used as the molten salt.

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. In this case, the amount of the polymer added is 1 to 50% by mass. In addition, γ-butyrolactone may be included in the electrolytic solution, thereby increasing the diffusion efficiency of iodide ions and improving the photoelectric conversion efficiency.

Examples of the polymer (polymer matrix) used for the gel electrolyte matrix include polyacrylonitrile and polyvinylidene fluoride.

The electrolyte may be made pseudo-solid by adding a gelling agent to an electrolyte solution composed of an electrolyte and a solvent to cause gelation (the pseudo-solid electrolyte is also referred to as “pseudo-solid electrolyte” hereinafter). 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 a polymer matrix, a crosslinkable polymer compound or monomer, a crosslinking agent, an electrolyte, and a solvent in the polymer may be used.
The polymer matrix is preferably a polymer having a nitrogen-containing heterocycle in the main chain or side chain repeating unit, a cross-linked product obtained by reacting these with an electrophilic compound, a polymer having a triazine structure, or a polymer having a ureido structure. Molecules, compounds containing liquid crystal compounds, polymers having an ether bond, polyvinylidene fluoride, methacrylates, acrylates, thermosetting resins, crosslinked polysiloxanes, polyvinyl alcohol (PVA), inclusion compounds such as polyalkylene glycols and dextrins, Examples include 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 of a cation moiety and iodine in one polymer, and the like may be added to these.

As the polymer matrix, a system containing a crosslinked polymer obtained by reacting a bifunctional or higher functional isocyanate group with a functional group such as a hydroxy group, an amino group, or a carboxy group 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, a solvent having a specific dielectric constant, and the like. The liquid electrolyte solution may be held in the solid electrolyte membrane or the pores. A preferred method for holding the liquid electrolyte solution is a method using a cloth-like solid such as a conductive polymer film, a fibrous solid, or a filter.

In addition to pyridine compounds such as 4-t-butylpyridine, electrolytes include aminopyridine compounds, benzimidazole compounds, aminotriazole compounds and aminothiazole compounds, imidazole compounds, aminotriazine compounds, urea compounds, amide compounds, and pyrimidines. It may contain a compound or a nitrogen-free heterocycle.

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. It is preferable to adjust the water content (content ratio) of the electrolytic solution to 0 to 0.1% by mass.
Iodine can also be used as an inclusion compound of iodine and cyclodextrin. Cyclic amidine may be used, and an antioxidant, hydrolysis inhibitor, decomposition inhibitor, and zinc iodide may be added.

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 organic hole transport material is preferably a conductive polymer such as polythiophene, polyaniline, polypyrrole and polysilane, and a spiro compound in which two rings share a central element having a tetrahedral structure such as C and Si, triarylamine, etc. And aromatic amine derivatives, triphenylene derivatives, nitrogen-containing heterocyclic derivatives, and liquid crystalline cyano derivatives.

Since the redox couple becomes an electron carrier, it is preferably contained at a certain concentration. 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.

<Counter electrode>
The

counter electrodes

4 and 48 preferably function as positive electrodes of the dye-sensitized solar cell. The

counter electrodes

4 and 48 can usually have the same configuration as that of the conductive support 1 or 41, but the substrate 44 is not necessarily required in a configuration in which the strength is sufficiently maintained. As the structure of the

counter electrodes

4 and 48, a structure having a high current collecting effect is preferable. In order for light to reach the photoreceptor layers 2 and 42, at least one of the conductive support 1 or 41 and the

counter electrode

4 or 48 must be substantially transparent. In the dye-sensitized solar cell of the present invention, the conductive support 1 or 41 is preferably transparent, and sunlight is preferably incident from the conductive support 1 or 41 side. In this case, it is more preferable that the

counter electrodes

4 and 48 have a property of reflecting light. As the

counter electrodes

4 and 48 of the dye-sensitized solar cell, a glass or plastic on which a metal or conductive oxide is vapor-deposited is preferable, and a 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 includes, for example, 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 be applied to the photoelectric conversion element and the dye-sensitized solar cell described in the publication. Also, JP 2004-152613 A, JP 2000-90989 A, JP 2003-217688 A, JP 2002-367686 A, JP 2003-323818 A, JP 2001-43907 A, 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-2002-280857, JP-A-2001-2001. No. 273937, JP-A 2000-285 77 No. photoelectric conversion device described in JP-A-2001-320068, can be applied to a dye-sensitized solar cell.

[Method for producing photoelectric conversion element and dye-sensitized solar cell]
The photoelectric conversion element and the dye-sensitized solar cell of the present invention are preferably produced using a dye solution (the dye solution of the present invention) containing the metal complex dye of the present invention and a solvent.

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 an alcohol solvent, an amide solvent, a nitrile solvent, a hydrocarbon solvent, and a mixed solvent of two or more of these are more preferable. As the mixed solvent, a mixed solvent of an alcohol solvent and a solvent selected from an amide solvent, a nitrile solvent, or a hydrocarbon solvent is preferable. More preferably, it is a mixed solvent of an alcohol solvent and an amide solvent, a mixed solvent of an alcohol solvent and a hydrocarbon solvent, a mixed solvent of an alcohol solvent and a nitrile solvent, and particularly preferably a mixed solvent of an alcohol solvent and an amide solvent, an alcohol solvent and a nitrile solvent. It is a mixed solvent. Specifically, a mixed solvent of at least one of methanol, ethanol, propanol and t-butanol and at least one of dimethylformamide and dimethylacetamide, at least one of methanol, ethanol, propanol and t-butanol, and acetonitrile The mixed solvent is 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 above formula (CA) is preferable.
Here, the dye solution of the present invention is a dye solution 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. Is preferred. In the present invention, the dye solution of the present invention preferably contains 0.001 to 0.1% by mass of the metal complex dye of the present invention. The amount of coadsorbent used is as described above.

The water content of the dye solution is preferably adjusted. In the present invention, the water content is preferably adjusted to 0 to 0.1% by mass.

In the present invention, the photoreceptor layer is preferably prepared by supporting the metal complex dye represented by the formula (I) or a dye containing the same on the surface of the semiconductor fine particles using the dye solution. That is, the photoreceptor layer is preferably formed by applying the above dye solution (including a dip method) to semiconductor fine particles provided on a conductive support, and drying or curing.
In particular, when the metal complex dye represented by the formula (I) is adsorbed, the influence of the adsorption time on the photoelectric conversion efficiency is small, and the adsorption time of the metal complex dye can be shortened. That is, even if the adsorption amount of the metal complex dye is small, the photoelectric conversion efficiency equivalent to that of the conventional dye-sensitized solar cell is exhibited. Thus, the dye-sensitized solar cell of the present invention is less affected by the adsorption amount of the metal complex dye, and exhibits excellent photoelectric conversion efficiency even when the adsorption amount is reduced.
When the dye solution of the present invention is used, it is excellent in manufacturing latitude when manufacturing a photoelectric conversion element and a dye-sensitized solar cell.
The photoelectric conversion element or the dye-sensitized solar cell of the present invention can be obtained by further providing a charge transfer layer, a counter electrode, and the like on the light-receiving electrode provided with the photoreceptor layer thus prepared.

The dye-sensitized solar cell is manufactured by connecting the external circuit 6 to the conductive support 1 and the counter electrode 4 of the photoelectric conversion element manufactured as described above.

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

Below, the synthesis | combining method of the metal complex dye of this invention is demonstrated.
In this specification, room temperature means 25 degreeC. Me represents methyl and TBA represents tetrabutylammonium.
The metal complex dye and synthetic intermediate synthesized in Example 1 were identified by MS (mass spectrum) measurement.
Since the synthesized TBA salt of the metal complex dye is protonated and has the same mass as the electrically neutral metal complex dye in the MS measurement, the result of the MS measurement is omitted for the TBA salt.

Example 1 (Synthesis of metal complex dye)
The metal complex dyes (D-1) to (D-13) synthesized in this example are shown below.

(Synthesis of Metal Complex Dye (D-1) and Metal Complex Dye (D-1TBA))
A metal complex dye (D-1) and a metal complex dye (D-1TBA) were synthesized according to the following scheme.

(I) Synthesis of Compound (1-2) 2-Chloro-4-iodopyridine (Compound (1-1)), diphenylamine, and t-butoxy sodium were added to toluene, and degassing was repeated by repeating reduced pressure and nitrogen gas replacement. did. Xantphos and palladium acetate were added there, and it heated up until it recirculate | refluxed. After reacting for 2 hours under reflux, the mixture was allowed to cool. The reaction solution was extracted by adding an aqueous ammonium chloride solution and ethyl acetate. The organic phase was washed with saturated brine, dried over magnesium sulfate and filtered. The crude product was obtained by concentrating the filtrate. The resulting crude product was purified by silica gel column chromatography to obtain compound (1-2).

(Ii) Synthesis of Compound (1-4) Compound (1-2) and hexamethyldistin were added to toluene, and deaeration was repeated by repeating reduced pressure (vacuum) and nitrogen gas replacement. Tetrakis (triphenylphosphine) palladium (0) was added thereto, and the mixture was heated and reacted for 8 hours under reflux. Compound (1-3) was added to the obtained liquid, and the mixture was further reacted for 3 hours under reflux. The resulting reaction mixture was allowed to cool and then concentrated, and the concentrated residue was purified by silica gel column chromatography to obtain a compound (1-4) which is a diethyl esterified product of a terpyridine compound.
Compound (1-4) was confirmed from the following data.
MS (ESI ⁺ ) m / z: 546 ([M + H] ⁺ )

(Iii) Synthesis of Compound (1-5) Compound (1-4) and ruthenium trichloride trihydrate were added to ethanol, and the mixture was reacted under reflux for 2 hours. The reaction mixture was allowed to cool and the precipitate was collected by filtration. The precipitate was washed with ethanol to obtain compound (1-5). The obtained compound (1-5) was used in the next reaction without purification.

(Iv) Synthesis of Compound (1-7) Compounds (1-5) and (1-6) were added to 1-pentanol, and the mixture was heated to reflux and reacted for 3 hours. The reaction mixture was allowed to cool and then concentrated, and the concentrated residue was purified by silica gel column chromatography to obtain compound (1-7).
Compound (1-7) was confirmed from the following data.
MS (ESI ⁺ ) m / z: 1060 ([M + H] ⁺ )

(V) Synthesis of Compound (1-8) Compound (1-7) and ammonium thiocyanate were added to 1-pentanol, and the mixture was reacted under reflux for 6 hours. The reaction mixture was allowed to cool and then concentrated, and the concentrated residue was purified by silica gel column chromatography to obtain compound (1-8).
Compound (1-8) was confirmed from the following data.
MS (ESI ^<+> ) m / z: 1083 ([M + H] ^< +>)

(Vi) Synthesis of Metal Complex Dye (D-1) Compound (1-8) was added to DMF (N, N-dimethylformamide), and 3M aqueous sodium hydroxide solution was added dropwise thereto. After the mixture was reacted at room temperature for 30 minutes, 1 M (mol / L) trifluoromethanesulfonic acid methanol solution was added to the obtained reaction product to adjust to acidic (pH = 2.5). Water was added to the resulting liquid, and the precipitated solid was collected by filtration, washed with water, and then vacuum dried. In this way, a metal complex dye (D-1) was obtained.

The metal complex dye (D-1) was confirmed from the following data.
MS (ESI ⁺ ) m / z: 1027 ([M + H] ⁺ )

(Vii) Synthesis of metal complex dye (D-1TBA) In a recovery flask, a metal complex dye (D-1) (103 mg, 0.10 mmol) and a 10% MeOH solution of tetrabutylammonium hydroxide (TBAOH) (259 mg, 0.10 mmol) and allowed to react at room temperature. The obtained reaction solution was concentrated to obtain 129 mg of a metal complex dye (D-1TBA).

(Synthesis of metal complex dyes (D-2) to (D-13) and metal complex dyes (D-2TBA) to (D-13TBA))
Metal complex dyes (D-2) to (D-13) were synthesized in the same manner as metal complex dye (D-1), except that the compounds used were changed. That is, in the above-described method for synthesizing a metal complex dye (the above scheme), except that each of diphenylamine, compound (1-1) and compound (1-6) is changed to a compound compatible with the metal complex dye for synthesis. In the same manner as for the complex dye (D-1), metal complex dyes (D-2) to (D-13) were synthesized.
In addition, metal complex dyes (D-4), (D-11) and (D-12) were synthesized without performing a reaction for introducing an NCS group. Furthermore, metal complex dyes (D-8) and (D-10) were synthesized by directly NCS-converting the compound corresponding to compound (1-5), respectively.
The metal complex dyes (D-2TBA) to (D-13TBA) are respectively 10% MeOH of TBAOH in such an amount that the molar ratio of the metal complex dyes (D-2) to (D-13) and TBAOH is 1: 1. The solution was synthesized in the same manner as the metal complex dye (D-1TBA).

(Identification of metal complex dyes (D-2) to (D-13) and metal complex dyes (D-2TBA) to (D-13TBA))
The synthesized metal complex dyes (D-2) to (D-13) were confirmed from the following data.
Metal Complex Dye (D-2) MS (ESI ⁺ ) m / z: 1140 ([M + H] ⁺ )
Metal Complex Dye (D-3) MS (ESI ⁺ ) m / z: 1105 ([M + H] ⁺ )
Metal Complex Dye (D-4) MS (ESI ⁺ ) m / z: 1268 ([M + H] ⁺ )
Metal Complex Dye (D-5) MS (ESI ⁺ ) m / z: 1259 ([M + H] ⁺ )
Metal Complex Dye (D-6) MS (ESI ⁺ ) m / z: 1021 ([M + H] ⁺ )
Metal Complex Dye (D-7) MS (ESI ⁺ ) m / z: 1015 ([M + H] ⁺ )
Metal Complex Dye (D-8) MS (ESI ⁺ ) m / z: 765 ([M + H] ⁺ )
Metal Complex Dye (D-9) MS (ESI ⁺ ) m / z: 1027 ([M + H] ⁺ )
Metal Complex Dye (D-10) MS (ESI ⁺ ) m / z: 765 ([M + H] ⁺ )
Metal Complex Dye (D-11) MS (ESI ⁺ ) m / z: 1180 ([M + H] ⁺ )
Metal Complex Dye (D-12) MS (ESI ⁺ ) m / z: 1213 ([M + H] ⁺ )
Metal Complex Dye (D-13) MS (ESI ⁺ ) m / z: 1067 ([M + H] ⁺ )

Example 2 (Production of dye-sensitized solar cell)
Using the metal complex dyes (D-1) to (D-13) and (D-1TBA) to (D-13TBA) synthesized in Example 1, or the following comparative compounds (C-1) and (C-2), respectively Thus, the dye-sensitized solar cell 20 (5 mm × 5 mm scale) shown in FIG. 2 was manufactured. Manufacture was performed according to the following procedure. The following performance of each of the produced dye-sensitized solar cells 20 was evaluated. The results are shown in Table 1.

(Preparation of light receiving electrode precursor)
A fluorine-doped SnO ₂ conductive film (transparent conductive film 43, film thickness: 500 nm) was formed on a glass substrate (substrate 44, thickness 4 mm) to produce a conductive support 41. Then, titania paste “18NR-T” (manufactured by DyeSol) was screen printed on the SnO ₂ conductive film and dried at 120 ° C. Next, the titania paste “18NR-T” was screen-printed again and dried at 120 ° C. for 1 hour. Thereafter, the dried titania paste was baked in air at 500 ° C. to form a semiconductor layer 45 (layer thickness: 10 μm). Further, a titania paste “18NR-AO” (manufactured by DyeSol) was screen-printed on the semiconductor layer 45 and dried at 120 ° C. for 1 hour. Thereafter, the dried titania paste was baked at 500 ° C., and a light scattering layer 46 (layer thickness: 5 μm) was formed on the semiconductor layer 45.
In this way, the photoreceptor layer 42 (light receiving surface area: 5 mm × 5 mm, layer thickness: 15 μm, metal complex dye not supported) is formed on the SnO ₂ conductive film, and the metal complex dye is not supported. A light receiving electrode precursor was prepared.

(Dye adsorption [A])
Next, each of the metal complex dyes ((D-1) to (D-13) and (D-1TBA) to (D-13TBA) synthesized in Example 1 on the photoreceptor layer 42 that does not carry the metal complex dye. ) Was supported as follows. First, each of the metal complex dyes is dissolved in a 1: 1 (volume ratio) mixed solvent of t-butanol and acetonitrile so as to have a concentration of 2 × 10 ⁻⁴ mol / L, and the ^coadsorbent is further dissolved therein. As a result, 30 mol of cholic acid was added to 1 mol of the metal complex dye to prepare each dye solution. Next, the light-receiving electrode precursor produced in each dye solution was immersed at 25 ° C. for 45 hours, pulled up from the dye solution, and then dried.
In this manner, each of the light receiving electrodes 40 in which each metal complex dye was supported on the light receiving electrode precursor was produced.

(Dye adsorption [B])
In the same manner as in “Dye adsorption [A]”, except that the light receiving electrode precursor prepared in each dye solution was immersed at 25 ° C. for 7 hours, the light receiving electrode 40 carrying each metal complex dye on the light receiving electrode precursor was prepared. Each was produced.

(Assembly of dye-sensitized solar cell)
As the counter electrode 48, a platinum electrode (Pt thin film thickness: 100 nm) having the same shape and size as the conductive support 41 was prepared. In addition, as an electrolytic solution, iodine 0.1M (mol / L), lithium iodide 0.1M, 4-t-butylpyridine 0.5M and 1,2-dimethyl-3-propylimidazolium iodide 0.6M were used. A liquid electrolyte was prepared by dissolving in acetonitrile. Further, a spacer S “Surlin” (trade name, manufactured by DuPont) having a shape matched to the size of the photoreceptor layer 42 was prepared.
Each of the light-receiving electrodes 40 and the counter electrode 48 manufactured as described above are thermocompression-bonded so as to face each other via the spacer S, and then the electrolyte solution injection port is interposed between the photoreceptor layer 42 and the counter electrode 48. The charge transfer layer 47 was formed by filling the liquid electrolyte. The outer periphery of the battery thus prepared and the electrolyte injection port were sealed and cured using Resin XNR-5516 (manufactured by Nagase Chemtech), and each dye-sensitized solar cell (Sample Nos. 1 to 13) was sealed. Manufactured.

The dye-sensitized solar cells of the respective sample numbers include those using electrically neutral metal complex dyes (D-1 to D-13) and TBA salt metal complex dyes (D-1TBA to D-13TBA). 2 types including those using.
In addition, in the dye-sensitized solar cell of each sample number, the dye-sensitized solar cell using an electrically neutral metal complex dye adsorbs (supports) each metal complex dye on the semiconductor fine particles by dye adsorption [A]. Dye-sensitized solar cell (sample number may be given “A”) and dye-sensitized solar cell in which each metal complex dye is adsorbed to semiconductor fine particles by dye adsorption [B] (sample number “B” ") May be added).
Similarly, a dye-sensitized solar cell using a metal complex dye of TBA salt includes a dye-sensitized solar cell in which each metal complex dye is adsorbed on semiconductor fine particles by dye adsorption [A], and a dye-sensitized solar cell by dye adsorption [B]. It includes two types of dye-sensitized solar cells in which metal complex dyes are adsorbed on semiconductor fine particles.

For comparison, the above dyes were used except that the following metal complex dyes (C-1) and (C-2) were used in place of the metal complex dyes synthesized in Example 1 in the production of the dye-sensitized solar cells. Dye-sensitized solar cells (sample numbers c1 and c2) were produced in the same manner as in the production of sensitized solar cells.
The metal complex dye (C-1) is an electrically neutral metal complex dye of the compound “A-5” described in Patent Document 3. The metal complex dye (C-2) is the compound “D-40” described in Patent Document 4.

<Test of photoelectric conversion efficiency>
A battery characteristic test was performed using each of the produced dye-sensitized solar cells. The battery characteristic test was performed by irradiating 1000 W / m ² of simulated sunlight from a xenon lamp through an AM1.5 filter using a solar simulator (WXS-85H, manufactured by WACOM). The current-voltage characteristics were measured using an IV tester to determine the photoelectric conversion efficiency.

(Conversion efficiency (A))
Of the dye-sensitized solar cells of each sample number, the dye-sensitized solar cells (sample numbers 1A to 13A and c1A and c2A) in which each metal complex dye is adsorbed to the semiconductor fine particles by dye adsorption [A] are as described above. Thus, photoelectric conversion efficiency was measured (referred to as conversion efficiency (A)). The measured conversion efficiency (A) was evaluated. The evaluation was based on the conversion efficiency (S _A ) of the dye-sensitized solar cell (sample number c1A) in which the metal complex dye (C-1) was adsorbed on the semiconductor fine particles by dye adsorption [A].
In the evaluation criteria for the conversion efficiency (A), “A” and “B” are acceptable levels of this test, and preferably “A”. On the other hand, “C” and “D” have insufficient conversion efficiency and do not reach the pass level (required level) of the present invention.
(Evaluation criteria for conversion efficiency (A))
Conversion efficiency (A) is compared to conversion efficiency (S _A )
A: More than 1.2 times B: More than 1.1 times and less than 1.2 times C: More than 1.0 times and less than 1.1 times D: Less than 1.0 times

(Conversion efficiency (B))
The dye-sensitized solar cells (sample numbers 1B to 13B and c1B and c2B) in which each metal complex dye is adsorbed to the semiconductor fine particles by dye adsorption [B] among the dye-sensitized solar cells of the respective sample numbers are also described above. Thus, the photoelectric conversion efficiency was measured (referred to as conversion efficiency (B)). The measured conversion efficiency (B) was evaluated. The evaluation was based on the conversion efficiency (S _A ) of the dye-sensitized solar cell (sample number c1A) in which the metal complex dye (C-1) was adsorbed on the semiconductor fine particles by dye adsorption [A].
In the evaluation criteria for the conversion efficiency (B), “A” and “B” are acceptable levels of this test, and preferably “A”. On the other hand, “C” and “D” have insufficient conversion efficiency and do not reach the pass level (required level) of the present invention.
(Evaluation criteria for conversion efficiency (B))
Conversion efficiency (B) is compared to conversion efficiency (S _A )
A: More than 1.1 times B: More than 1.0 times, 1.1 times or less C: More than 0.9 times, 1.0 times or less D: 0.9 times or less

<Durability evaluation>
Dye-sensitized solar cells (sample numbers 1A to 13A and c1A and c2A) in which each metal complex dye is adsorbed to semiconductor fine particles by dye adsorption [A] among the dye-sensitized solar cells of each sample number are used for durability. A heat cycle test was performed as a property (thermal degradation) evaluation.
Each dye-sensitized solar cell was alternately placed in a −10 ° C. freezer and a 50 ° C. thermostat every 12 hours, and cooling and heating were repeated (heat cycle test). The current was measured for each of the dye-sensitized solar cell before the heat cycle test and the dye-sensitized solar cell after 72 hours of the heat cycle test. The current value (short-circuit current density) obtained from the current-voltage characteristic measurement in the dye-sensitized solar cell 72 hours after the heat cycle test is the current value (short-circuit current density) measured in the dye-sensitized solar cell before the heat cycle test. Divided by. This value was defined as the current retention rate. The durability was evaluated based on the following criteria based on the current retention ratio thus obtained.
In the durability evaluation criteria, “A” and “B” are acceptable levels of this test, and preferably “A”. On the other hand, “C” and “D” have insufficient current holding ratios and do not reach the pass level (required level) of the present invention.
A: 0.9 times or more B: Less than 0.9 times, 0.8 times or more C: Less than 0.8 times, 0.7 times or more D: Less than 0.7 times

<Measurement of dye adsorption amount>
Each of the light receiving electrodes 40 of the photoelectric conversion element manufactured in each example was immersed in a 10% methanol solution (3 mL) of tetrabutylammonium hydroxide, and the temperature was 20 ° C. with a twist mixer (model number: TM-300, manufactured by ASONE). The metal complex dye adsorbed on each light receiving electrode 40 was desorbed by shaking for 16 hours under the condition of 45 rpm. The ultraviolet-visible absorption spectrum of the solution is measured as it is, the number of moles of adsorption (mmol) is calculated from a calibration curve prepared in advance, and this is divided by the surface area (cm ² ) of the conductive support 41 to obtain the dye adsorption amount. (Mmol / cm ² ) was calculated. In any of the examples, it was visually confirmed that the adsorbed dye was desorbed after the treatment under the above desorption conditions.
The adsorption amount (mmol / cm ² ) thus obtained was evaluated. The dye adsorption amount (mmol / cm ² ) obtained from the photoelectric conversion element produced using the dye adsorption [A] was obtained from the photoelectric conversion element produced using the adsorption amount (A) and the dye adsorption [B]. The amount of dye adsorption (mmol / cm ² ) was defined as the amount of adsorption (B). The evaluation is based on the relative value with the amount of adsorption (A) when the metal complex dye (C-1) is adsorbed as the reference (1.00), for both the amount of adsorption (A) and the amount of adsorption (B). went.

From the results in Table 1, the following can be understood.
Sample Nos. 1 to 13 (invention) all use metal complex dyes (D-1 to D-13) having the above tridentate ligand LA in which an amino group is introduced into the terminal pyridine ring of terpyridine. It was. In the photoelectric conversion element and the dye-sensitized solar cell (sample numbers 1 to 13) of the present invention in which such metal complex dyes (D-1 to D-13) are supported on semiconductor fine particles, both conversion efficiency ( A) and conversion efficiency (B) were both high, and the current holding ratio was also high.
In Sample Nos. 1 to 13 (invention), the adsorption amount (B) in which the adsorption time is shorter than the adsorption time of the adsorption amount (A) has a reduced adsorption amount of the metal complex dye. However, the adsorption amounts (B) of the sample numbers 1 to 13 are both larger than the adsorption amounts (B) of the sample numbers c1 and c2, and the conversion efficiency (B) in the sample numbers 1 to 13 is the conversion efficiency ( The evaluation results were the same as in A). That is, in all of the metal complex dyes (D-1 to D-13), the influence of the adsorption time of the metal complex dye on the photoelectric conversion efficiency was small. Therefore, even if the adsorption time is shortened and the amount of adsorption of the metal complex dye is thereby reduced, high photoelectric conversion efficiency can be realized.

In particular, in a photoelectric conversion element and a dye-sensitized solar cell (sample numbers 1 to 8 and 11 to 13), an amino group at the 4-position ring atom with respect to the ring-constituting nitrogen atom coordinated to the metal ion of the terminal pyridine ring Metal complex dyes (D-1 to 8 and 11 to 13) into which groups were introduced were used. These photoelectric conversion elements and dye-sensitized solar cells (sample numbers 1 to 8 and 11 to 13) all exhibited high photoelectric conversion efficiency. Moreover, the influence of the adsorption time of the metal complex dye on the photoelectric conversion efficiency is small, and even when the adsorption time is shortened from 45 hours to 7 hours, the conversion efficiency is excellent.
Further, in the photoelectric conversion element and the dye-sensitized solar cell (sample numbers 1 to 5, 9 and 11 to 13), the ligand LA into which a diarylamino group is introduced and the bidentate or tridentate ligand LD described above are used. The metal complex dyes (D-1 to 5, 9, and 11 to 13) were used. As a result, all of them maintained high conversion efficiency and further increased the current holding ratio.
Further, in the photoelectric conversion element and the dye-sensitized solar cell (sample numbers 1 to 7 and 11 to 13), the amino group is bonded to the ring constituent atom at the 4-position with respect to the ring constituent nitrogen atom coordinated to the metal ion of the terminal pyridine ring. Metal complex dyes (D-1 to 7 and 11 to 13) having a ligand LA into which a group was introduced and the bidentate or tridentate ligand LD described above were used. As a result, all of them maintained high conversion efficiency (A), and conversion efficiency (B) and current holding ratio were further increased.
In addition, the metal complex dye of the present invention imparts the above characteristics excellent to photoelectric conversion elements and dye-sensitized solar cells as shown in Table 1, regardless of whether they are electrically neutral or TBA salts. did it.

Furthermore, the metal complex dye of the present invention could be suitably used as a sensitizing dye of the photoelectric conversion element and dye-sensitized solar cell of the present invention. In addition, the dye solution of the present invention containing the metal complex dye of the present invention and a solvent could be suitably used for preparing semiconductor fine particles carrying the metal complex dye of the present invention. In particular, as described above, it has been found that even if the adsorption time is shortened, a photoelectric conversion element and a dye-sensitized solar cell with high photoelectric conversion efficiency can be manufactured, and the manufacturing latitude is excellent. Further, the terpyridine compound of the present invention was suitable as a ligand for the metal complex dye of the present invention, and particularly its esterified product was suitable as a ligand precursor for the metal complex dye of the present invention. .

On the other hand, the photoelectric conversion element and the dye-sensitized solar cell (sample numbers c1 and c2) in which the metal complex dye not having the ligand LA is supported on the semiconductor fine particles are at least acceptable in terms of conversion efficiency. Did not reach. In particular, when the adsorption time was shortened, the amount of adsorption decreased and the photoelectric conversion efficiency was lowered, and the influence of the adsorption time of the metal complex dye on the photoelectric conversion efficiency was large.
Specifically, in the photoelectric conversion element and dye-sensitized solar cell of sample number c1, a metal complex dye having a tridentate ligand having a C ₂₉ H ₅₉ CONH group introduced at the 4-position of the terminal pyridine ring of terpyridine (C-1) was used. The C ₂₉ H ₅₉ CONH group is a substituent containing a nitrogen atom, the same as the amino group. However, in the photoelectric conversion element and the dye-sensitized solar cell (sample number c1), none of the conversion efficiency (A), the conversion efficiency (B), and the current retention rate reached the acceptable level.
In the photoelectric conversion element and dye-sensitized solar cell of sample number c2, a metal complex dye (C-2) having a tridentate ligand having an alkoxyphenyl group introduced at the 3-position of the terminal pyridine ring of terpyridine is used. Using. In this photoelectric conversion element and dye-sensitized solar cell (sample number c2), even when the ligand LD is a tridentate ligand, both the conversion efficiency (A) and the conversion efficiency (B) reach acceptable levels. There wasn't.

While this invention has been described in conjunction with its embodiments, we do not intend to limit our invention in any detail of the description unless otherwise specified and are contrary to the spirit and scope of the invention as set forth in the appended claims. I think it should be interpreted widely.

This application claims priority based on Japanese Patent Application No. 2014-199250 filed in Japan on September 29, 2014, the contents of which are incorporated herein by reference. Capture as part.

DESCRIPTION OF SYMBOLS 1,41 Conductive support body 2,42 Photoconductor layer 21 Dye 22 Semiconductor

fine particle

3,47 Charge

transfer body layer

4,48

Counter electrode

5,40 Photosensitive electrode 6 External circuit 10 Photoelectric conversion element 100 Application of photoelectric conversion element to battery use System M operating means (eg electric motor)
20 Dye-sensitized solar cell 43 Transparent conductive film 44 Substrate 45 Semiconductor layer 46 Light scattering layer S Spacer

Claims

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 a metal represented by the following formula (I) A photoelectric conversion element having semiconductor fine particles carrying a complex dye.
Formula (I) M (LA) (LD) p (LX) q · (CI) z
In the formula, M represents a metal ion.
LA represents a tridentate ligand represented by the following formula (LA-1).
LD represents a bidentate or tridentate ligand. p represents 0 or 1;
LX represents a monodentate ligand. q represents 3 when p is 0, represents 0 when p is 1 and LD is a tridentate ligand, and represents 1 when p is 1 and LD is a bidentate ligand. .
CI represents a counter ion necessary for neutralizing the charge of the metal complex dye. z represents an integer of 0 to 3.

In the formula, Za, Zb and Zc each independently represent a group of nonmetallic atoms necessary to complete a 5-membered or 6-membered ring. However, at least one of the rings formed by Za and Zb has an acidic group. R 1 and R 2 each independently represents an alkyl group or an aromatic ring group.
The ring formed by Za, the ring formed by Zb and the ring formed by Zc are each independently a pyridine ring, pyrimidine ring, pyrazine ring, pyridazine ring, triazine ring, tetrazine ring, quinoline ring, imidazole ring, triazole. The photoelectric conversion element according to claim 1, wherein the photoelectric conversion element is at least one selected from the group consisting of a ring, a thiazole ring, an oxazole ring, a benzimidazole ring, a benzotriazole ring, a benzoxazole ring, and a benzothiazole ring.
The photoelectric conversion element according to claim 1, wherein the M is Ru 2+ or Os 2+ .
The photoelectric conversion element according to any one of claims 1 to 3, wherein the LA is represented by the following formula (LA-2).

Wherein, R 1 and R 2 are each the same meaning as R 1 and R 2 in the formula (LA-1). Anc1 and Anc2 each independently represent an acidic group.
The photoelectric conversion element according to any one of claims 1 to 4, wherein each of R 1 and R 2 is an aryl group.
The photoelectric conversion device according to any one of claims 1 to 5, wherein the acidic group is a carboxy group or a salt thereof.
7. The photoelectric conversion element according to claim 1, wherein the LD is a bidentate ligand represented by any one of the following formulas (2L-1) to (2L-4): .

In the formula, ring D 2L represents an aromatic ring. A 111 to A 141 each independently represents an anion of a nitrogen atom or an anion of a carbon atom. R 111 to R 143 each independently represents a hydrogen atom or a substituent having no acidic group. * Represents a coordination position to the metal ion M.
7. The photoelectric conversion element according to claim 1, wherein the LD is a tridentate ligand represented by any one of the following formulas (3L-1) to (3L-4): .

In the formula, ring D 2L represents an aromatic ring. A 211 to A 242 each independently represents a nitrogen atom or a carbon atom. However, in each of A 211 and A 212 , A 221 and A 222 , A 231 and A 232 , and A 241 and A 242 , at least one is an anion. R 211 to R 241 each independently represent a hydrogen atom or a substituent having no acidic group. * Represents a coordination position to the metal ion M.
A dye-sensitized solar cell comprising the photoelectric conversion element according to any one of claims 1 to 8.
A metal complex dye represented by the following formula (I).
Formula (I) M (LA) (LD) p (LX) q · (CI) z
In formula (I), M represents a metal ion.
LA represents a tridentate ligand represented by the following formula (LA-1).
LD represents a bidentate or tridentate ligand. p represents 0 or 1;
LX represents a monodentate ligand. q represents 3 when p is 0, represents 0 when p is 1 and the LD is a tridentate ligand, and 1 when p is 1 and the LD is a bidentate ligand. Represents.
CI represents a counter ion necessary for neutralizing the charge of the metal complex dye. z represents an integer of 0 to 3.

In the formula, Za, Zb and Zc each independently represent a group of nonmetallic atoms necessary to complete a 5-membered or 6-membered ring. However, at least one of the rings formed by Za and Zb has an acidic group. R 1 and R 2 each independently represents an alkyl group or an aromatic ring group.
A dye solution containing the metal complex dye according to claim 10 and a solvent.
A terpyridine compound represented by the following formula (LA-2) or an esterified product thereof.

In the formula, R 1 and R 2 each independently represents an alkyl group or an aromatic ring group. Anc1 and Anc2 each independently represent an acidic group.