JP6308152B2 - Photoelectric conversion element, dye-sensitized solar cell, and dye solution - Google Patents

Description

  The present invention relates to a photoelectric conversion element, a dye-sensitized solar cell, and a dye solution.

  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 dye-sensitized solar cells has been vigorously conducted. In particular, it was the research results of Graetzel and others at the Swiss Lausanne University of Technology. They adopted a structure in which a dye composed of a ruthenium complex was fixed on the surface of a porous titanium oxide 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.
To date, 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, metal complex dyes exhibiting improvements in photoelectric conversion efficiency of photoelectric conversion elements and dye-sensitized solar cells have been developed.
For example, Patent Document 1 discloses a metal complex dye having a terpyridine ligand, a pyrazolylpyridine bidentate ligand having an aromatic heterocycle such as a thiophene ring at the 4-position of the pyridine ring, and a monodentate ligand. Describes metal complex dyes in which 1.0 mol% or more of isomers coexist.
Patent Document 2 describes a metal complex dye having a terpyridine ligand, a pyrazolylpyridine bidentate ligand having a thiophene ring at the 3-position with respect to the nitrogen atom of the pyridine ring, and a monodentate ligand. Has been.

JP 2014-209578 A JP2013-72080A

For practical application of a photoelectric conversion element or a dye-sensitized solar cell, it is required that a photoelectric conversion element or a dye-sensitized solar cell with further improved stability of battery performance such as photoelectric conversion efficiency can be produced.
In this regard, Patent Document 1 describes that when the metal complex dye described in Patent Document 1 is used, the performance of the photoelectric conversion element or the solar cell can be stably maintained even if it is repeatedly manufactured. However, battery performance required for photoelectric conversion elements and dye-sensitized solar cells is increasing year by year. Accordingly, there is still room for improvement in the stability of battery performance (manufacturing variation in battery performance) when a photoelectric conversion element or a dye-sensitized solar cell is manufactured under the same conditions.
In addition to the stability of the battery performance when the photoelectric conversion element or the dye-sensitized solar cell is manufactured under the same conditions, the photoelectric conversion element or the dye-sensitized solar cell is stable even when the manufacturing conditions are changed. It is also required to show performance. In the production of a photoelectric conversion element or a dye-sensitized solar cell, the temperature (adsorption temperature) of the dye solution containing the metal complex dye is likely to change in the step of adsorbing the metal complex dye to the semiconductor fine particles. However, even if it shows stable battery performance if manufactured under the same conditions, if the manufacturing conditions such as adsorption temperature change, the battery performance of the photoelectric conversion element or dye-sensitized solar cell will fluctuate (adsorption of battery performance). Temperature dependence) and stability were not sufficient. This problem becomes prominent in continuous production and mass production.

The present invention relates to a photoelectric conversion element having a small fluctuation in photoelectric conversion efficiency and exhibiting stable battery performance even when manufactured under the same manufacturing conditions and the adsorption temperature varies, and a dye-sensitized solar cell using the same It is an issue to provide.
It is another object of the present invention to provide a dye solution capable of producing a photoelectric conversion element that exhibits sufficiently stable battery performance.

  The present inventors diligently investigated the stabilization of the battery performance of the photoelectric conversion element and the dye-sensitized solar cell. As a result, a pyridine ligand having an aromatic heterocycle at the 3-position with respect to the nitrogen atom of the pyridine ring and terpyridine are used. When a metal complex dye having a specific structure having a ligand and an NCS ligand is adsorbed on a semiconductor fine particle together with its isomer, and the content of the isomer in the all metal complex dye is a specific ratio, the same It was found that the battery performance of the photoelectric conversion element and the dye-sensitized solar cell can be highly stabilized even when the adsorption temperature fluctuates in addition to the production under the production conditions. Based on this knowledge, the present invention has been further studied and completed.

That is, the subject of this invention was solved by the following means.
<1> A photoelectric conversion element having a conductive support, a photoreceptor layer containing an electrolyte, a charge transfer layer containing an electrolyte, and a counter electrode,
The photoreceptor layer has semiconductor fine particles on which a metal complex dye represented by the following formula (1) and an isomer of the metal complex dye are supported,
The isomer includes at least one of a bond isomer represented by the following formula (2) and a geometric isomer represented by the following formula (3):
The isomers less than 50 mol% der content of more than 0.1 mol% in total of the metal complex in the dye is, the content of the case containing bound isomer is less than 0.5 mole% to 20 mole% A photoelectric conversion element having a content of 0.5 mol% or more and less than 20 mol% when a geometric isomer is contained .

In the formula, each M independently represents a hydrogen ion or a cation. X ¹ represents a nitrogen atom or CR ² . X ² represents a nitrogen atom when X ¹ is a nitrogen atom, and represents a nitrogen atom or CR ³ when X ¹ is CR ² . R ^{1 to} R ³ each independently represents a hydrogen atom, an alkyl group, a heteroaryl group, an aryl group, or a halogen atom. G ¹ represents a group represented by the following formula (G1).

In the formula, R ⁴ represents an alkyl group, an alkynyl group, an alkenyl group, an alkoxy group, an alkylthio group, an amino group, a heteroaryl group or an aryl group. R ⁵ represents a hydrogen atom, an alkyl group, an alkynyl group, an alkenyl group, an alkoxy group, an alkylthio group, an amino group, a heteroaryl group or an aryl group. m represents an integer of 1 to 3. n represents an integer of 0 to 2. Y ¹ represents an oxygen atom, a sulfur atom, NRf, a selenium atom, C (Rf) ₂ or Si (Rf) ₂ . Rf represents a hydrogen atom or an alkyl group. * Represents a bond to the pyridine ring in formula (1) .

The photoelectric conversion element as described in <1> whose content rate of a <2 > isomer is 0.3 mol% or more and less than 30 mol% in total.
<3> ^{X 2} is a nitrogen atom <1> or the photoelectric conversion element <4> n according to <2>, 0 <1> to photoelectric conversion according to any one of <3> element.
<5> ^{Y 1} is a sulfur or oxygen atom <1> to photoelectric conversion device according to any one of <4>.
<6> ^{R 1} is an alkyl group or an aryl group <1> to photoelectric conversion device according to any one of <5>.
< 7 > The photoelectric conversion device according to any one of <1> to < 6 >, wherein R ⁵ is an alkyl group, an alkynyl group, an alkenyl group, an alkoxy group, or an alkylthio group.
< 8 > A dye-sensitized solar cell using the photoelectric conversion element according to any one of <1> to < 7 >.
<9> and a metal complex dye represented by the following formula (1), and isomers of the metal complex dye, a dye solution containing a solvent,
The isomer includes at least one of a bond isomer represented by the following formula (2) and a geometric isomer represented by the following formula (3):
The isomers less than 50 mol% der content of more than 0.1 mol% in total of the metal complex in the dye is, the content of the case containing bound isomer is less than 0.5 mole% to 20 mole% A dye solution having a geometric isomer content of 0.5 mol% or more and less than 20 mol% .

In the formula, each M independently represents a hydrogen ion or a cation. X ¹ represents a nitrogen atom or CR ² . X ² represents a nitrogen atom when X ¹ is a nitrogen atom, and represents a nitrogen atom or CR ³ when X ¹ is CR ² . R ^{1 to} R ³ each independently represents a hydrogen atom, an alkyl group, a heteroaryl group, an aryl group, or a halogen atom. G ¹ represents a group represented by the following formula (G1).

In the formula, R ⁴ represents an alkyl group, an alkynyl group, an alkenyl group, an alkoxy group, an alkylthio group, an amino group, a heteroaryl group or an aryl group. R ⁵ represents a hydrogen atom, an alkyl group, an alkynyl group, an alkenyl group, an alkoxy group, an alkylthio group, an amino group, a heteroaryl group or an aryl group. m represents an integer of 1 to 3. n represents an integer of 0 to 2. Y ¹ represents an oxygen atom, a sulfur atom, NRf, a selenium atom, C (Rf) ₂ or Si (Rf) ₂ . Rf represents a hydrogen atom or an alkyl group. * Represents a bond to the pyridine ring in formula (1).

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 symbol or formula, or when a plurality of substituents are specified simultaneously, unless otherwise specified The respective substituents 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.

  Further, a ring, for example, an aromatic ring or an aliphatic ring may be further condensed to form a condensed ring.

  In this specification, about the display of a compound (a complex and a pigment | dye are included), it uses for the meaning containing its salt and its ion besides the compound itself. In addition, it means that a part of the structure is changed as long as the desired effect is achieved. Furthermore, a compound that does not clearly indicate substitution or non-substitution means that it may have an arbitrary substituent within a range that exhibits a desired effect. The same applies to substituents, linking groups and ligands.

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

  Even if the photoelectric conversion element and the dye-sensitized solar cell of the present invention are manufactured under the same manufacturing conditions and the adsorption temperature varies, the variation in photoelectric conversion efficiency is small and stable battery performance is exhibited. Moreover, the dye solution of the present invention can produce a photoelectric conversion element that exhibits sufficiently stable battery performance.

In the system which applied the photoelectric conversion element of the 1st mode of the present invention to battery use, it is a sectional view showing typically also the enlarged view of the circle part in a layer. It is sectional drawing which showed typically the dye-sensitized solar cell which consists of a photoelectric conversion element of the 2nd aspect of this 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, the semiconductor fine particles forming the photoreceptor layer as a whole are a metal complex dye represented by the formula (1) described later as a sensitizing dye, and a metal complex dye that is an isomer thereof. Is carried. Therefore, at least a part of the semiconductor fine particles may carry both the metal complex dye represented by the formula (1) and its isomer, or may carry only one of them. 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 other metal complex dyes together with the metal complex dye represented by the formula (1) described later and isomers thereof.

  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.

  The photoelectric conversion element of the present invention is not particularly limited except for 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, 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. 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>
-Metal complex dyes and isomers represented by formula (1)-
The metal complex dye used in the present invention (hereinafter also referred to as ruthenium complex dye) includes a metal complex dye represented by the following formula (1) (sometimes referred to as a metal complex dye (1)), and Isomer.

In the formula, each M independently represents a hydrogen ion or a cation. X ¹ represents a nitrogen atom or CR ² . X ² represents a nitrogen atom when X ¹ is a nitrogen atom, and represents a nitrogen atom or CR ³ when X ¹ is CR ² . R ^{1 to} R ³ each independently represents a hydrogen atom, an alkyl group, a heteroaryl group, an aryl group, or a halogen atom. G ¹ represents a group represented by the following formula (G1).

(Notation method of configuration in metal complex dye)
First, using the skeleton structure of the metal complex dye (1), the notation method of the steric configuration of the chemical structural formula in the metal complex dye will be described.
In this specification, the three-dimensional structure of a metal complex dye is shown using the following notation (I). The metal complex dye represented by the following (I) includes a terpyridine ligand having three pyridine rings of ring A, a pyrazolylpyridine bidentate ligand in which a pyridine ring of ring B and a pyrazole ring of ring C are bonded, NCS (isothiocyanate group) has a three-dimensional structure coordinated (bonded) to Ru in an octahedral manner. Here, among the bonds to Ru, in the following notation (I), a bond indicated by a normal straight line indicates a bond on the paper surface (that is, the same plane), and a bond indicated by a wedge-shaped thick line is in front of the paper surface. This represents a bond, and a wedge-shaped broken line represents a bond on the other side (back side) of the page.
That is, the structure represented by the following (I) is represented by the following (II) when clearly expressed using a left-handed coordinate system of a three-dimensional orthogonal coordinate system. In this structure, with Ru as the origin, three pyridine rings of ring A and ring B of terpyridine ligand are arranged on the xy plane, and a pyrazole ring of ring C is arranged on the negative side of the z-axis. In this structure, NCS (isothiocyanate group) is arranged on the positive side of the z-axis.

(Trans and cis configuration)
In addition, the trans configuration in the present invention refers to two types of octahedral hexacoordination complexes as described in “Basic Master Inorganic Chemistry” (2010, Ohmsha), page 240, edited by Hideki Masuda and Kunhei Nagashima. It means that the position of the ligand is on the opposite side across the metal ion. This trans configuration has a geometric isomer relationship with the cis configuration in which the positions of the two ligands are adjacent to each other. In the present invention, the trans configuration-cis configuration represents the positional relationship between the pyridine ring of L ^{2 in} the lower diagram and X in the lower diagram, and the structures of the metal complex dye (1) and its geometric isomer are respectively A cis configuration and a trans configuration, which are schematically represented as follows.

In the above schematic diagram, L ¹ represents a terpyridine ligand composed of three pyridine rings, and each pyridine ring is represented by an N circled letter. L ² represents a bidentate ligand composed of a pyridine ring and a nitrogen-containing 5-membered ring, the pyridine ring is represented by a circled letter N, and the nitrogen-containing 5-membered ring is represented by G. X represents NCS (isothiocyanate group). M ^I represents Ru.

(Metal complex dye represented by formula (1) and isomers thereof)
Next, the metal complex dye represented by the formula (1) and its isomer will be described.
The metal complex dye as an isomer used in the present invention is an isomer of the metal complex dye (1).
The isomers of the metal complex dye (1) are isomers based on the complex structure of the metal complex dye, and various isomers are exemplified. Examples thereof include stereoisomers and structural isomers.
Representative examples of stereoisomers include, for example, E isomers and Z isomers (E / Z isomers) in the double bond of a substituent, and geometric isomers based on the spatial arrangement (absolute configuration) of the ligand with respect to the central metal. Is mentioned.
On the other hand, typical examples of structural isomers include ionized isomers, coordination isomers, bond isomers, and the like. The bond isomer refers to an isomer in which a ligand (bidentate ligand) that can coordinate with different atoms, for example, an NCS group (isothiocyanate group) is coordinated with different atoms. For example, in the metal complex dye (1) in which the NCS group is coordinated with the nitrogen atom, the bond isomer is a metal complex dye in which the NCS group is coordinated with the sulfur atom (represented by the formula (2) described later). Metal complex dyes).

  In the present invention, the isomer of the metal complex dye (1) does not include an optical isomer based on a substituent having an asymmetric carbon atom, and when M of the metal complex dye (1) is a cation, It does not include isomers due to differences in cation bonding positions (pyridine ring of terpyridine ligand).

Here, the metal complex dye (1) and its isomer will be specifically described.
The metal complex dye (1) is the following dye a, in which a terpyridine ligand having three pyridine rings, a bidentate ligand composed of a pyridine ring and a nitrogen-containing 5-membered ring, and an NCS group (isothiocyanate group) are Ru. It is coordinated in octahedral.
Examples of the bond isomer of the metal complex dye (1) include the following dye b in which the coordination atom of the NCS group is a sulfur atom with respect to the following structure a in which the coordination atom of the NCS group is a nitrogen atom. .
As the geometric isomer of the metal complex dye (1), for example, a nitrogen-containing 5-membered ring in a bidentate ligand is bonded with a wedge-shaped thick line around the Ru, and the NCS group is a wedge-shaped broken line. The following dye c in which the pyridine ring in the bidentate ligand is bonded by a wedge-shaped thick line and the NCS group is bonded by a wedge-shaped broken line (trans configuration) is bonded to the following dye a that is bonded (cis configuration). Can be mentioned.
Examples of other isomers include a geometric-bond isomer of the NCS group in which the coordination atom is a sulfur atom in the geometric isomer of c, and an E-form and a Z-form in the double bond of the substituent. More specifically, the substituents G ¹ having a pyridine ring of ring B include E-form and Z-form in the double bond portions of the case with olefin.
^M in the following dyes a to c, X ^1, X 2, ^{R 1} and ^{G 1} are as defined ^M, and X ^1, X 2, ^{R 1} and ^{G 1} in formula (1) described later.

  The dye b is a metal complex dye represented by formula (2) described later, and the dye c is a metal complex dye represented by formula (3) described later.

In the present invention, the metal complex dye (1) is used in combination with the isomer of the metal complex dye (1) at the following isomer content ratio, so that the adsorption temperature varies even if it is produced under the same production conditions. Even if it changes, the fluctuation | variation of photoelectric conversion efficiency is small and the stable battery performance can be provided to a photoelectric conversion element and a dye-sensitized solar cell.
The isomer used in combination with the metal complex dye (1) is preferably a geometric isomer, a bond isomer, or a geometric isomer and a bond isomer in terms of stability of battery performance. The bond isomer is preferable as the isomer because it is excellent in the adsorption temperature dependency and the effect of reducing the production variation.

  The metal complex dye (1) and the isomer can be confirmed (identified) by peaks appearing at different positions (retention times) in high performance liquid chromatography (HPLC). Therefore, the content of the metal complex dye (1) or isomer with respect to the total amount of the metal complex dye (1) and its isomer can be determined by HPLC, respectively. The content of each metal complex dye is, for example, using a high performance liquid chromatography apparatus (Shimadzu Corporation) as a measurement condition, column: YMC-Pac ODS-AM, model number AM-312, temperature 40 ° C., detection wavelength 254 nm, flow rate When the eluent is THF (tetrahydrofuran) / water / TFA (trifluoroacetic acid) at 1.0 mL / min, it can be determined from the area ratio of each peak obtained.

In the present invention, the content of isomers (referred to as isomer content) is 0.1 mol% in total with respect to the total metal complex dye (total number of moles of metal complex dye (1) and its isomer). More than 50 mol%. That is, in the present invention, the metal complex dye adsorbed on the semiconductor fine particles contains the metal complex dye (1) and at least one isomer corresponding thereto, and the content of the metal complex dye (1). Is 50 mol% or more and 99.9 mol% or less, and the isomer content is 0.1 mol% or more and less than 50 mol% in total.
The lower limit of the isomer content is preferably 0.2 mol% or more, more preferably 0.3 mol% or more, more preferably 0.5 mol% in total in all metal complex dyes from the viewpoint of stability of battery characteristics. % Or more is more preferable, 0.8 mol% or more is further preferable, 1.0 mol% or more is particularly preferable, and 1.5 mol% or more is most preferable. The upper limit of the content of isomers is preferably 40 mol% or less, more preferably 35 mol% or less, and even more preferably less than 30 mol% in total in all metal complex dyes from the viewpoint of stability of battery characteristics. 25 mol% or less is particularly preferable, and 20 mol% or less is most preferable. The isomer content can be in a range where the upper limit and the lower limit are appropriately combined.
The content rate of a metal complex pigment | dye (1) is determined so that the content rate of a metal complex pigment | dye (1) and an isomer may be 100 mol% in total.
The content of each isomer will be described later.

In the present invention, the isomer content can be set within a predetermined range by an appropriate method. For example, there is a method in which a dye solution containing each metal complex dye at a predetermined content is prepared, and each metal complex dye is adsorbed on semiconductor fine particles using this dye solution. As will be described later, the dye solution containing each metal complex dye at a predetermined content is synthesized by separately synthesizing the metal complex dye (1) and each isomer and dissolving them in a solvent at a predetermined content. Can be prepared.
Another method is to use each dye solution containing each metal complex dye, and set the concentration or coating amount of the dye solution so as to obtain a predetermined content, and each metal complex dye is converted into a semiconductor fine particle. Can also be adsorbed in order.
A method for synthesizing and purifying each metal complex dye will be described later.

Hereinafter, the metal complex dye used in the present invention will be described.
-Metal complex dye represented by formula (1)-
The metal complex dye (1) is represented by the following formula (1).

In the formula, each M independently represents a hydrogen ion or a cation. X ¹ represents a nitrogen atom or CR ² . X ² represents a nitrogen atom when X ¹ is a nitrogen atom, and represents a nitrogen atom or CR ³ when X ¹ is CR ² . R ^{1 to} R ³ each independently represents a hydrogen atom, an alkyl group, a heteroaryl group, an aryl group, or a halogen atom. G ¹ represents a structure represented by the following formula (G1).

In the present invention, the metal complex dye (1) is used in combination with the following isomer with an isomer content in the above range, and the metal complex dye (1) is a bidentate ligand comprising a nitrogen-containing 5-membered ring and a pyridine ring. When the substituent G ¹ is present at the 3-position of the pyridine ring in (the 5-position when the carbon atom bonded to the nitrogen-containing 5-membered ring is the 2-position starting from the nitrogen atom coordinated to ruthenium in the pyridine ring) Stable battery performance can be imparted to the photoelectric conversion element and the dye-sensitized solar cell. The reason for this is not clear yet, but is estimated as follows. That is, when the metal complex dye (1) was adsorbed on the surface of the semiconductor fine particles, because they are located in parallel to a state close to the surface substituent G ¹ is the semiconductor fine particles, metal complex dye at the surface of semiconductor fine particles (1) It is considered that the agglomeration (micro agglomeration in the adsorption state affecting the battery performance) hardly occurs. On the other hand, the metal complex dye (1) and its isomer are different in the adsorption rate and adsorption state on the semiconductor fine particles. Thereby, the crystallinity of a metal complex pigment | dye (1) falls and it becomes difficult to aggregate. Further, when isomers having different adsorption states and the like are adsorbed on the semiconductor fine particles with the above content, the aggregation suppressing effect due to the substituent G ¹ of the metal complex dye (1) is further enhanced, compared with the conventional metal complex dye. Thus, it is considered that the metal complex dye (1) is adsorbed on the semiconductor fine particles in a more homogeneous adsorption state. Thus, by using the metal complex dye (1) having the isomer content in the above-mentioned range and adsorbing the isomer and having the substituent G ¹ at a specific substitution position, the battery temperature is affected by the adsorption temperature and the production. Any variation can be reduced.

  In the metal complex dye (1), the cation that M can take is not particularly limited, and examples thereof include a positive counter ion (excluding a hydrogen ion) in the following counter ion CI. Of these, alkali metal ions or ammonium ions are preferred.

The alkyl group, heteroaryl group, aryl group and halogen atom in R ^{1 to} R ³ are preferably corresponding groups in the substituent Z ^R described later.

The alkyl group that can be taken as R ^{1 to} R ³ is more preferably an alkyl group substituted with an electron withdrawing group, and further preferably an alkyl group substituted with a halogen atom, particularly a fluorine atom. In the alkyl group substituted with a halogen atom, the number of halogen atoms to be substituted is not particularly limited, and is preferably 1 or more and preferably the number of hydrogen atoms of the alkyl group, more preferably 1 to 6, and more preferably 1 ~ 3 are more preferred. Among them, the alkyl group substituted with a halogen atom is preferably a perhalogenated alkyl group in which all the hydrogen atoms of the alkyl group are substituted, more preferably a perfluoroalkyl group, and even more preferably trifluoromethyl.

The aryl group that can be adopted as R ^{1 to} R ³ is more preferably an aryl group substituted with an electron withdrawing group, and more preferably an aryl group substituted with a halogen atom, particularly a fluorine atom. In the aryl group substituted with a halogen atom, the number of halogen atoms to be substituted is not particularly limited, and is preferably 1 or more, and preferably less than or equal to the number of hydrogen atoms of the aryl group, more preferably 2 to 5. ~ 5 are more preferred. Among them, the aryl group substituted with a halogen atom is preferably a phenyl group substituted with a halogen atom, for example, 2,3,4,5-tetrafluorophenyl or 2,3,4,5,6-pentafluorophenyl. Can be mentioned.

R ¹ is preferably an alkyl group, an aryl group or a heteroaryl group, more preferably an alkyl group or an aryl group, and more preferably an alkyl group substituted with a fluorine atom or an aryl group substituted with a fluorine atom. An alkyl group substituted with a fluorine atom is more preferable, and trifluoromethyl is particularly preferable.

R ² is preferably a hydrogen atom or an alkyl group among the above groups, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and even more preferably a hydrogen atom.
R ³ is preferably a hydrogen atom.

X ¹ is preferably CR ² .
X ² represents a nitrogen atom or CR ³ by X ¹ as described above, and a nitrogen atom is preferable. The combination of X ¹ and X ² (hereinafter described in the order of (X ¹ , X ² )) is preferably (nitrogen atom, nitrogen atom) or (CR ² , nitrogen atom), (nitrogen atom, nitrogen atom) or (CH, nitrogen atom) is more preferable, and (CH, nitrogen atom) is more preferable.

G ¹ is a group represented by the following formula (G1).

In the formula, R ⁴ represents an alkyl group, an alkynyl group, an alkenyl group, an alkoxy group, an alkylthio group, an amino group, a heteroaryl group or an aryl group. R ⁵ represents a hydrogen atom, an alkyl group, an alkynyl group, an alkenyl group, an alkoxy group, an alkylthio group, an amino group, a heteroaryl group or an aryl group.
m represents an integer of 1 to 3. n represents an integer of 0 to 2.
Y ¹ represents an oxygen atom, a sulfur atom, NRf, a selenium atom, C (Rf) ₂ or Si (Rf) ₂ . Here, Rf represents a hydrogen atom or an alkyl group. * Represents a bond to the pyridine ring in formula (1).

Each group defined by R ⁴ , R ⁵ and Rf is preferably a corresponding group in the substituent Z ^R described later.

R ⁴ is preferably an alkyl group, an alkoxy group, an alkylthio group, an amino group, an aryl group, or a heteroaryl group, and more preferably an alkyl group, an alkoxy group, an alkylthio group, an amino group, or a heteroaryl group. An alkyl group, an alkoxy group or an alkylthio group is more preferable.
n is preferably 0 or 1, more preferably 1 when R ⁵ is a hydrogen atom, if R ⁵ is not hydrogen atom 0 are more preferred.
When n is 2, two R ⁴ may be bonded to each other to form a ring, or adjacent R ⁴ and R ⁵ may be bonded to form a ring. Examples of the ring formed include an aryl ring such as a benzene ring, a heteroaryl ring such as a pyrazine ring and a pyrrole ring, an unsaturated hydrocarbon ring such as a cyclopentadiene ring, a 1,4-dioxane ring, 2 , 3-dihydropyrazine ring and the like which do not show an aromatic attribute.

R ⁵ is preferably a hydrogen atom, an alkyl group, an alkynyl group, an alkenyl group, an alkoxy group, an alkylthio group or an amino group, and an alkyl group, an alkynyl group, an alkenyl group, an alkoxy group or an alkylthio group among the above groups. More preferred is an alkyl group, an alkynyl group or an alkylthio group. The heteroaryl group which can be adopted as R ⁵ does not include the ring containing Y ¹ in the above formula (G1).

Y ¹ is preferably an oxygen atom or a sulfur atom, and more preferably a sulfur atom.
m is preferably 1 or 2.
when m is 2 or 3, among R ⁴ having the ring containing the adjacent Y ^1, R ⁴ is bonded to the ring containing the other Y ¹ to form a ring having the ring containing one Y ¹ Alternatively, R ^{4 s in} two adjacent rings including Y ¹ may be bonded to form a ring. The ring formed is synonymous with the ring formed by R ⁴ described above.

  The group represented by the formula (G1) is preferably a group represented by any of the following formulas (G1-1a) to (G1-5a), and is represented by the formula (G1-1a) or the formula (G1-5a). The group represented by Formula (G1-1a) is more preferable.

In formula ^{(G1-1a) ~ (G1-5a),} R 5, Y 1 and m are in the formula ^(G1), has the same meaning as R 5, ^{Y 1} and m, the preferred range is also the same. R ⁶ represents a hydrogen atom, an alkyl group, an alkynyl group, an alkenyl group, an alkoxy group, an alkylthio group, an amino group, a heteroaryl group or an aryl group. Each group that can be taken as R ⁶ has the same meaning as each group that can be taken as R ⁴ in formula (G1), and the preferred range is also the same, but a hydrogen atom is particularly preferred.

Z ¹ represents a nitrogen atom or CRa, and is preferably a nitrogen atom.
Z ² and Z ³ each independently represent an oxygen atom, a sulfur atom, NRb, CRb ₂ , a selenium atom or Si (Rb) ₂ . Z ² is preferably NRb or C (Rb) ₂ , and Z ³ is preferably an oxygen atom or a sulfur atom, more preferably an oxygen atom.
Ra and Rb each independently represents a hydrogen atom or an alkyl group. Alkyl group for Ra and Rb are preferably alkyl groups of the substituents Z ^R described later.

-Isomer represented by formula (2)-
In the present invention, an isomer represented by the following formula (2) is preferable as the isomer used in combination with the metal complex dye (1).

^{Wherein, M,} X ^{1, X} 2, R ¹ and ^{G 1} have the same meanings ^M, and X ^{1, X} 2, R ¹ and ^{G 1} in the formula (1), and their preferable ranges are also the same.

When the bond isomer represented by the above formula (2) is used in combination with the metal complex dye (1), the aggregation suppression effect of the metal complex dye (1) can be enhanced, and the adsorption temperature dependency reducing effect is excellent. .
In the present invention, the lower limit of the content of the bond isomer represented by the formula (2) is preferably 0.2 mol% or more, more preferably 0.5 mol% or more, and further preferably 1 mol% or more. Further, the upper limit of the content is preferably 25 mol% or less, more preferably less than 20 mol%, further preferably 15 mol% or less, and particularly preferably 10 mol% or less. The isomer content represented by the formula (2) can be in a range in which the upper limit value and the lower limit value are appropriately combined.

-Isomer represented by formula (3)-
In the present invention, an isomer represented by the following formula (3) is also preferred as the isomer used in combination with the metal complex dye (1).

^{Wherein, M,} X ^{1, X} 2, R ¹ and ^{wherein G 1} is as defined ^M, and X ^{1, X} 2, R ¹ and ^{G 1} in the formula (1), and their preferable ranges are also the same.

When the geometric isomer represented by the above formula (3) is used in combination with the metal complex dye (1), the aggregation suppressing effect of the metal complex dye (1) can be enhanced, and the manufacturing variation suppressing effect is excellent.
In the present invention, the lower limit of the content of the geometric isomer represented by the formula (3) is preferably 0.2 mol% or more, more preferably 0.5 mol% or more, and further preferably 1 mol% or more. Further, the upper limit of the content is preferably 25 mol% or less, more preferably less than 20 mol%, further preferably 15 mol% or less, and particularly preferably 10 mol% or less. The isomer content represented by the formula (3) can be in a range in which the upper limit value and the lower limit value are appropriately combined.

  Each of the metal complex dyes and isomers used in the present invention includes a form containing a counter ion (CI) for neutralizing the charge of the dye.

  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, metal complex ions or hydrogen ions. The positive counter ion is preferably an inorganic or organic ammonium ion (such as triethylammonium or tetrabutylammonium ion) or a hydrogen ion.

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

  Examples of the metal complex dye represented by the above formula (1) and the isomers represented by the above formulas (2) and (3) include, for example, the method described in JP2013-084594A, Japanese Patent No. 4298799. A method described in U.S. Patent Application Publication No. 2013 / 0018189A1, U.S. 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. 2054-2058, Chem. Commun. , 2014, 50, p. It can be synthesized by the method described in 6379-6381, 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 according thereto.

  The metal complex dye (1) and each isomer can be usually synthesized as a mixture by changing synthesis conditions and the like. By purifying this mixture, each metal complex dye can be isolated. For example, in the case of geometric isomers, the raw materials for synthesis, or the heating temperature or solvent at the time of synthesis of an intermediate in which a terpyridine ligand and a pyridine bidentate ligand having a nitrogen-containing 5-membered ring are bonded to ruthenium are changed. By doing so, a mixture containing many geometric isomers can be obtained. In the case of bond isomers, a mixture containing a large amount of bond isomers can be obtained by changing the ligand concentration, heating temperature, solvent, or the like when the ligand is introduced into the metal. In the case of E isomer and Z isomer, it can be obtained by light irradiation during synthesis or by changing pH and heating temperature.

  Each of the metal complex dyes, particularly the metal complex dye (1), has a maximum absorption wavelength in a solution of preferably 300 to 900 nm, more preferably 350 to 850 nm, and particularly preferably 370 to 800 nm. Range. Moreover, it is preferable that the absorption wavelength region covers the entire 300 to 900 nm.

<Substituent group Z ^R >
The substituent in the present invention, substituents selected from Substituent Group Z ^R.
Substituent group Z ^R is a substituent group containing no acidic group.
In the present specification, when simply not listed only as substituents, it is intended to refer to the substituent group Z ^R. Also, each of the groups, for example, in the case of only an alkyl group, are described, preferable range of the corresponding group of the substituent group Z ^R, is a specific example is applied.

The group contained in the substituent group Z ^R, the following groups, and include a group formed by combining a plurality of the following groups.
An alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms such as methyl, ethyl, isopropyl, n-butyl, t-butyl, pentyl, hexyl, heptyl, octyl, 1-ethylpentyl, 2- Ethylhexyl, benzyl, 2-ethoxyethyl, fluoromethyl, trifluoromethyl or 2,2,2-trifluoro-1,1-dimethylethyl), an alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms). For example, vinyl, allyl, butenyl or oleyl), alkynyl groups (preferably having 2 to 20 carbon atoms, more preferably 2 to 12, for example, ethynyl, butynyl, octynyl or phenylethynyl), cycloalkyl groups (preferably 3 to 20 carbon atoms), cycloalkenyl group (preferably 5 to 20 carbon atoms) An aryl group (preferably having 6 to 26 carbon atoms, for example, phenyl, 1-naphthyl, 4-methoxyphenyl, 2-chlorophenyl, 3-methylphenyl, difluorophenyl, tetrafluorophenyl or bis (trifluoromethyl) phenyl), A heterocyclic group (preferably a 5- or 6-membered heterocyclic group having 2 to 20 carbon atoms and having at least one oxygen atom, sulfur atom or nitrogen atom is preferred. The heterocyclic group has aromaticity. And a heteroaliphatic ring group that does not exhibit aromaticity include, for example, 2-pyridyl, 2-thienyl, 2-furanyl, 3-pyridyl, 4-pyridyl, 2-pyridyl, and the like. Imidazolyl, 2-benzimidazolyl, 2-thiazolyl or 2-oxazolyl), an alkoxy group (preferably Prime number 1-20, more preferably 1-12, for example, methoxy, ethoxy, propyloxy, hexyloxy, octyloxy or benzyloxy), alkenyloxy groups (preferably having 2-20 carbon atoms, more preferably 2-12 carbon atoms). ), An alkynyloxy group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms), a cycloalkyloxy group (preferably having 3 to 20 carbon atoms), an aryloxy group (preferably having 6 to 26 carbon atoms), hetero A ring oxy group (preferably having 2 to 20 carbon atoms),

An alkoxycarbonyl group (preferably having 2 to 20 carbon atoms), a cycloalkoxycarbonyl group (preferably having 4 to 20 carbon atoms), an aryloxycarbonyl group (preferably having 6 to 20 carbon atoms), an amino group (preferably having 0 to 0 carbon atoms). 20 includes an alkylamino group, an alkenylamino group, an alkynylamino group, a cycloalkylamino group, a cycloalkenylamino group, an arylamino group, a heterocyclic amino group, such as amino, N, N-dimethylamino, N, N -Diethylamino, N-ethylamino, N-allylamino, N- (2-propynyl) amino, N-cyclohexylamino, N-cyclohexenylamino, N, N-diphenylamino, anilino, pyridylamino, imidazolylamino, benzimidazolylamino, thiazolylamino , Benzothiazo Ruamino or triazinylamino), a sulfamoyl group (preferably an alkyl, cycloalkyl or aryl sulfamoyl group having 0 to 20 carbon atoms), an acyl group (preferably 1 to 20 carbon atoms), an acyloxy group (preferably Carbon number 1-20), a carbamoyl group (preferably an carbamoyl group having 1-20 carbon atoms, alkyl, cycloalkyl or aryl),

An acylamino group (preferably having 1 to 20 carbon atoms), a sulfonamide group (preferably an alkyl, cycloalkyl or aryl sulfonamide group having 0 to 20 carbon atoms), an alkylthio group (preferably having 1 to 20 carbon atoms, More preferably, it is 1-12, for example, methylthio, ethylthio, isopropylthio, pentylthio, hexylthio, octylthio or benzylthio), cycloalkylthio group (preferably having 3 to 20 carbon atoms), arylthio group (preferably having 6 to 26 carbon atoms) An alkyl, cycloalkyl or arylsulfonyl group (preferably having 1 to 20 carbon atoms),

A silyl group (preferably a silyl group having 1 to 20 carbon atoms and substituted by alkyl, aryl, alkoxy and aryloxy), a silyloxy group (preferably having 1 to 20 carbon atoms, alkyl, aryl, alkoxy and aryloxy are A substituted silyloxy group is preferred), a hydroxy group, a cyano group, a nitro group, and a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom or an iodine atom).

Group selected from substituent group Z ^R is more preferably an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, a heterocyclic group, an alkoxy group, cycloalkoxy group, aryloxy group, alkoxycarbonyl group, cycloalkoxy carbonyl group Amino group, acylamino group, cyano group or halogen atom, particularly preferably an alkyl group, alkenyl group, heterocyclic group, alkoxy group, alkoxycarbonyl group, amino group, acylamino group or cyano group.

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

Specific examples of the metal complex dye (1) are shown below, but the present invention is not limited thereto. The following specific examples also show specific examples of NCS bond isomers and geometric isomers of pyridine bidentate ligands having a nitrogen-containing 5-membered ring.
When the metal complex dye of the following specific example contains the ligand which has a hydrogen ion dissociable group, a ligand may dissociate as needed and may discharge | release a hydrogen ion.

  Next, the preferable aspect of the main member of a photoelectric conversion element and a dye-sensitized solar cell is demonstrated.

<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, the material for forming the substrate 44 may be ceramic (Japanese Patent Laid-Open No. 2005-135902) or conductive resin (Japanese Patent Laid-Open No. 2001-160425). 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.

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

  The particle size of the semiconductor fine particles 22 is 0.001 to 1 μm as the primary particle in terms of the average particle size when the projected area is converted into a circle, and 0.01 to 100 μm as the average particle size of the dispersion. 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.

  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 using as a dye-sensitized solar cell, 1-50 micrometers is more preferable and 3-30 micrometers is more preferable.

  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, the metal complex dye (1) and an isomer of the metal complex dye (1) are used in combination as the sensitizing dye 21. In the present invention, it is only necessary to include one combination of such pigments. Therefore, in the present invention, as the sensitizing dye 21, at least one metal complex dye (1) and at least one isomer of the metal complex dye (1) are used. The metal complex dye (1) and isomers thereof are as described above.

  In the present invention, examples of the dye that can be used in combination with the metal complex dye (1) and its isomers include Ru complex dyes other than the metal complex dye (1) or isomers thereof, squarylium cyanine dyes, organic dyes, porphyrin dyes, or phthalocyanine dyes. Is mentioned.

  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. Further, the adsorption amount of the dye 21 to 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.

  When the metal complex dye (1) and its isomer are used in combination with another dye, the ratio of the total mass of the metal complex dye (1) and its isomer / the mass of the other dye is 95/5 to 10/90. Is preferable, 95/5 to 50/50 is more preferable, 95/5 to 60/40 is more preferable, 95/5 to 65/35 is particularly preferable, and 95/5 to 70/30 is most preferable.

  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 further use a coadsorbent together with the metal complex dye (1) and its isomer, 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 deoxycholic acid.
The co-adsorbent is preferably a co-adsorbent represented by the formula (CA) described in paragraph Nos. 0125 to 0129 of JP2014-82187A, and the number of paragraphs 0125 to 0129 of JP2014-82187A is preferable. The description is preferably incorporated herein as it is.

  The co-adsorbent has an effect of suppressing inefficient association of the metal complex dye and an effect of preventing reverse electron transfer from the surface of the semiconductor fine particles to the redox system in the electrolyte by being adsorbed on the semiconductor fine particles 22. Although the usage-amount of a coadsorbent is not specifically limited, From a viewpoint of expressing said effect | action effectively, Preferably it is 1-200 mol with respect to 1 mol of said metal complex pigment | dyes, More preferably, it is 10-150 mol, Most preferably, it is 20-50 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-2002-289274, and the description of JP-A-2002-289274 is preferably incorporated in the present specification as it is.

<Charge transfer layer>
The charge transfer layer 3 and 47 used in the photoelectric conversion element of the present invention is a layer having a function of replenishing electrons to the oxidant of the dye 21, and between the light receiving electrode 5 or 40 and the counter electrode 4 or 48. Provided.
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.

− Electrolyte −
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 the description of paragraphs 0144 to 0156 of JP2014-82189A is described below. 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.

  As the molten salt or gel electrolyte, those described in paragraph numbers 0205 and 0208-0213 of JP-A No. 2014-139931 are preferable, and those of paragraph numbers 0205 and 0208-0213 of JP-A No. 2014-139931 are preferable. The description is preferably incorporated herein as it is.

  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 as additives. 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) 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. As the organic hole transport material, those described in paragraph No. 0214 of JP-A-2014-139931 are preferable.

  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.

[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 use a dye solution (the dye solution of the present invention) containing the metal complex dye (1) and its isomer (at least one combination) and a solvent. Can be manufactured.

The metal complex dye (1) and its isomer contained in the dye solution of the present invention are as described above, and the preferred range is also the same.
In the dye solution of the present invention, the content of the metal complex dye (1) and its isomer is as described above, and the metal complex dye (1) and the isomer thereof are added to the total mole of the metal complex dye (1) and its isomer. ) Is 50 mol% or more and 99.9 mol% or less, and the isomer content is 0.1 mol% or more and less than 50 mol% in total. The preferred range of the content of the metal complex dye (1) and its isomers is as described above.

  Examples of the solvent to be used include the solvents described in JP-A No. 2001-291534, but are not particularly limited thereto. 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 preferred are alcohol solvents and amide solvents, mixed solvents of alcohol solvents and hydrocarbon solvents, and particularly preferred are mixed solvents of alcohol solvents and amide solvents. Specifically, a mixed solvent of at least one of methanol, ethanol, propanol and butanol and at least one of dimethylformamide, dimethylacetamide and acetonitrile is preferable.

The dye solution of the present invention may contain other components as necessary.
The dye solution preferably contains a co-adsorbent, and the co-adsorbent is preferably the above-mentioned co-adsorbent.
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 pigment solution preferably adjusts the water content. In the present invention, the water content is preferably adjusted to 0 to 0.1% by mass.

In the present invention, it is preferable to prepare a photoreceptor layer by supporting the metal complex dye (1) and its isomer or a dye containing these 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. Although the application | coating conditions of a pigment | dye solution are not specifically limited, For example, the conditions which apply | coat a 10-80 degreeC dye solution or immerse in a 10-80 degreeC dye solution for 1 to 72 hours are mentioned.
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.

  When a photosensitive layer is formed using the dye solution of the present invention, a photoelectric conversion element and a dye-sensitized solar cell exhibiting stable battery performance are manufactured even if the photosensitive layer is manufactured under the same manufacturing conditions or the adsorption temperature varies. it can. Thus, even if the adsorption temperature varies under the same manufacturing conditions, variations in battery performance can be suppressed. Therefore, according to the present invention, the degree of freedom of manufacturing conditions in mass production can be increased, and a photoelectric conversion element and a solar cell with a high manufacturing yield can be manufactured.

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

Example 1
[Synthesis of metal complex dyes]
The structures of the metal complex dyes (D-1) to (D-9) synthesized in this example and the metal complex dye (D-10) for comparison are shown below.

(Synthesis of metal complex dye (D-1))
A metal complex dye (D-1) was synthesized according to the following scheme. The meanings of the abbreviations in the following scheme and specification are as follows.
Ph: Phenyl THF: Tetrahydrofuran Et: Ethyl
^t Bu: t-butyl Me: Methyl DMF: N, N-dimethylformamide TfOH: trifluoromethanesulfonic acid

(I) Synthesis of Compound (1-3) Compound (1-1) (1.50 g, 7.50 mmol), Compound (1-2) (2.65 g, 8.25 mmol), cesium carbonate in a three-necked flask (3.18 g, 9.75 mmol), THF (7.5 mL) and water (0.75 mL) were charged, and the atmosphere was replaced with nitrogen. Tetrakis (triphenylphosphine) palladium (IV) (433 mg, 0.275 mmol) was added to this mixed solution and reacted at 75 ° C. for 4 hours. The reaction solution was allowed to cool to room temperature, and water and ethyl acetate were added to separate the layers. The obtained organic layer was dried over magnesium sulfate, filtered and concentrated. The resulting crude product was purified by silica gel column chromatography to obtain compound (1-3) (1.28 g, yield 60%).

(Ii) Synthesis of Compound (1-4) Compound (1-3) (4.60 g, 16.0 mmol), potassium t-butoxy (3.59 g), ethyl trifluoroacetate (4.55 g) in a three-necked flask 32.0 mmol) and toluene (138 mL) were charged and reacted at 80 ° C. for 2 hours. The reaction solution was allowed to cool to room temperature, and then a saturated aqueous ammonium chloride solution and ethyl acetate were added for liquid separation. The obtained organic layer was dried over magnesium sulfate, filtered and concentrated. To the obtained crude product, hydrazine monohydrate (1.92 g, 38.4 mmol) and ethanol (23 mL) were added and reacted at 80 ° C. for 3 hours. The reaction solution was allowed to cool to room temperature, concentrated hydrochloric acid was added and stirred for 30 minutes, and the reaction solution was neutralized with an aqueous sodium bicarbonate solution. Water and ethyl acetate were added to the obtained reaction solution for liquid separation. The obtained organic layer was dried over magnesium sulfate, filtered and concentrated. The resulting crude product was purified by silica gel column chromatography to obtain compound (1-4) (5.06 g, yield 83%).

(Iii) Synthesis of compound (1-6) In a three-necked flask, compound (1-5) (3.52 g, 5.73 mmol), compound (1-4) (2.06 g, 5.43 mmol) and DMF ( 18 mL) was added and reacted at 140 ° C. for 1 hour. The crude product obtained by concentration was purified by silica gel column chromatography (eluent: 2% methanol / chloroform) to obtain compound (1-6) (2.91 g, yield 55%).
Compound (1-6) was identified by MS (mass spectrum) measurement.

(Iv) Synthesis of Compound (1-7) Compound (1-6) (1.50 g, 1.63 mmol), ammonium thiocyanate (1.24 g, 16.3 mmol) and DMF (30 mL) were added to a three-necked flask. The mixture was charged and reacted at 120 ° C. for 5 hours. The reaction solution was allowed to cool to room temperature, and water and ethyl acetate were added to separate the layers. The obtained organic layer was dried over magnesium sulfate, filtered and concentrated. The resulting crude product was purified by silica gel column chromatography (eluent: 5% methanol / chloroform) to obtain compound (1-7) (954 mg, yield 62%).

(V) Synthesis of Metal Complex Dye (D-1) In a three-necked flask, compound (1-7) (945 mg, 1.00 mmol), THF (15 mL), methanol (15 mL) and 3N aqueous sodium hydroxide solution (2. 0 mL), and allowed to react at room temperature for 1 hour. The reaction solution was neutralized to pH 3.0 using 1N trifluoromethanesulfonic acid / methanol solution, the precipitated solid was collected by filtration, washed with methanol, and the metal complex dye (D-1) (885 mg, yield). 98%) was obtained.
The obtained metal complex dye (D-1) was identified by MS (mass spectrum) measurement (measured values are shown in Table 1). Further, it was confirmed by HPLC that this metal complex dye (D-1) does not contain a geometric isomer (D-1a) and a bond isomer (D-1b) described later. The HPLC measurement conditions were as described above, and the retention time of the metal complex dye (D-1) was 15.5 minutes.

(Vi) Synthesis of geometric isomer (D-1a) As the geometric isomer (D-1a) of the metal complex dye (D-1), the following compound (1-6a) is used instead of the compound (1-6). The compound was synthesized in the same manner as the metal complex dye (D-1) except that
The retention time on HPLC of the geometric isomer (D-1a) was 5.0 minutes.
The geometric isomer (D-1a) was identified by MS (mass spectrum) measurement.
ESI-MS m / z = 904.1 (M + H ^< + ^> )
Compound (1-6a) is the same as compound (1-6) except that the following compound (1-9) was used instead of compound (1-5) and the reaction conditions were changed to the reaction conditions described in the following scheme. And synthesized. The crude compound (1-6a) thus obtained was purified by silica gel column chromatography (eluent: 5% methanol / chloroform) to obtain compound (1-6a). This compound (1-6a) was identified by MS measurement and ¹ H-NMR measurement. Details will be described later.

Here, the results of MS measurement and ¹ H-NMR measurement of the intermediate (1-6a) are shown below.

Compound (1-6a)
¹ H-NMR (CDCl ₃ )
δ = 0.90 (t, J = 6 Hz, 3H), 1.42 (t, J = 8 Hz, 9H), 1.30-1.80 (m, 8H), 2.88 (t, J = 6 Hz) , 2H), 4.46 (q, J = 8 Hz, 4H), 4.63 (q, J = 8 Hz, 2H), 6.60 (s, 1H), 6.99 (d, J = 3.6 Hz). , 1H), 7.52 (d, J = 3.6 Hz, 1H), 7.75 (dd, J = 2, 5.6 Hz, 2H), 7.82 (d, J = 8.4 Hz, 1H) , 8.00 (d, J = 5.6 Hz, 2H), 8.18 (dd, J = 2, 8.4 Hz, 1H), 8.77 (s, 2H), 8.92 (s, 2H) , 10.31 (d, J = 1.6Hz, 1H)
MS
ESI-MS m / z = 965.2 (M + H ⁺ )

(Vii) Synthesis of bond isomer (D-1b) As the bond isomer (D-1b) of the metal complex dye (D-1), the following compound (1-7b) was used instead of the compound (1-7). The compound was synthesized in the same manner as the metal complex dye (D-1) except that
The retention time in HPLC of the coupling isomer (D-1b) was 12.2 minutes.
The binding isomer (D-1b) was identified by MS (mass spectrum) measurement.
ESI-MS m / z = 904.1 (M + H ⁺ )
Compound (1-7b) was synthesized in the same manner as Compound (1-7) except that the reaction conditions were changed to those described in the following scheme. The crude product (1-7b) obtained was purified by silica gel column chromatography. The mixing ratio “1: 1” of “DMF / 1-pentanol” in the following scheme is a volume ratio.

  The obtained compound (1-7b) was identified as an SCN isomer because it was obtained from the compound (1-6) and has the same molecular weight as the NCS isomer compound (1-7).

(Adjustment of metal complex dyes (D-2) to (D-10))
In the same manner as the metal complex dye (D-1), and its geometric isomer (D-1a) and bond isomer (D-1b), metal complex dyes (D-2) to (D-10), and The respective geometric isomers and bond isomers were synthesized.

The synthesized metal complex dyes (D-1) to (D-10) were each identified by MS (mass spectrum) measurement. The results are summarized in Table 1 below.
The geometric isomer and bond isomer of each metal complex dye were identified in the same manner as the geometric isomer (D-1a) and bond isomer (D-1b).

[Manufacture of dye-sensitized solar cells: standard cells]
A dye-sensitized solar cell shown in FIG. 2 using the metal complex dyes (D-1) to (D-10) synthesized in the above [Synthesis of metal complex dye] and the geometrical isomers and bond isomers. 20 (5 mm × 5 mm scale) was produced. This manufacture was performed by the method shown below. About each manufactured dye-sensitized solar cell 20, the following performance was evaluated.

(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, the SnO ₂ conductive film, titania paste "18NR-T" a (Dyesol Inc.) was screen-printed, 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)
Next, the metal complex dyes (D-1) to (D-10) and isomers synthesized in the above [Synthesis of metal complex dyes] and isomers are applied to the photoreceptor layer 42 not supporting the metal complex dye as follows. And supported. First, each of the metal complex dyes is provided with the corresponding geometric isomer and bond isomer so that the isomer content shown in Table 2 below (100 mol% in total with the content of each metal complex dye) is obtained. Added and mixed. The obtained metal complex dye mixture was mixed in a 1: 1 (volume ratio) mixed solvent of t-butanol and acetonitrile so that the total metal complex dye concentration would be 2 × 10 ⁻⁴ mol / L. In addition, 30 mol of deoxycholic acid as a coadsorbent was added to 1 mol of all metal complex dyes to prepare each dye solution. Next, the light receiving electrode precursor was immersed in each dye solution at 25 ° C. for 20 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.

(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. Further, as an electrolytic solution, iodine 0.1M, lithium iodide 0.1M, 4-t-butylpyridine 0.5M and 1,2-dimethyl-3-propylimidazolium iodide 0.6M were dissolved in acetonitrile. A liquid electrolyte was prepared. 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 inlet were sealed and cured using Resin XNR-5516 (trade name, manufactured by Nagase Chemtech Co., Ltd.), and each dye-sensitized solar cell (standard battery) Sample numbers 101 to 125, c01 to 07) were produced.

(Evaluation of adsorption temperature dependence)
The dependence of photoelectric conversion efficiency on the temperature at the time of dye adsorption was evaluated as follows.
In the manufacture of the above [Manufacture of dye-sensitized solar cell: standard battery] (sample numbers 101 to 125 and c01 to 07), except that the light receiving electrode precursor was immersed in each dye solution at 15 ° C. and 35 ° C. for 20 hours. Were the same as the above [Manufacturing of dye-sensitized solar cell: Standard battery] (Dye adsorption condition: immersion at 25 ° C. for 20 hours) to manufacture dye-sensitized solar cells of each sample number. In this way, three types of dye-sensitized solar cells with different adsorption conditions (adsorption temperatures) were produced for the dye-sensitized solar cells of each sample number. The photoelectric conversion efficiency of each obtained dye-sensitized solar cell was measured. Photoelectric conversion efficiency was measured by the following method. Using a solar simulator (trade name “WXS-85H” manufactured by WACOM), a battery characteristic test was performed by irradiating 1000 W / m ² of pseudo-sunlight from a xenon lamp through an AM1.5 filter. Current-voltage characteristics were measured using a tester.
Among the photoelectric conversion efficiencies of the three types of batteries thus measured, the relative value of the measured value with the lowest photoelectric conversion efficiency when the measured value with the highest photoelectric conversion efficiency is 1 (the lowest photoelectric conversion efficiency / the highest High photoelectric conversion efficiency) was calculated. The adsorption temperature dependency was evaluated by this relative value. In the evaluation of the adsorption temperature dependency, a case where the relative value is 0.92 or more is a pass level of this test, preferably 0.95 or more, and more preferably 0.98 or more. When the relative value is less than 0.92, the adsorption temperature dependency is not sufficient, and the passing level of this test is not reached.

(Evaluation of manufacturing variation in photoelectric conversion efficiency)
The manufacturing variation in photoelectric conversion efficiency when a plurality of dye-sensitized solar cells were manufactured was evaluated.
Seven dye-sensitized solar cells of each sample number were manufactured in the same manner as in the above [Manufacturing of dye-sensitized solar cell: standard battery] (sample numbers 101 to 125 and c01 to 07). The photoelectric conversion efficiency of each obtained dye-sensitized solar cell was measured in the same manner as described above (evaluation of adsorption temperature dependency). The relative value (lowest photoelectric conversion efficiency / highest photoelectric conversion efficiency) of the measured value with the lowest photoelectric conversion efficiency when the measured value with the highest photoelectric conversion efficiency was 1 was calculated. Manufacturing variation was evaluated based on this relative value. In the evaluation of manufacturing variation, the relative value of 0.92 or more is the acceptable level of the present invention, preferably 0.95 or more, and more preferably 0.98 or more. Those having a relative value of less than 0.92 have large manufacturing variations and do not reach the acceptable level of the present invention.

From the results in Table 2, the following can be understood.
In the dye-sensitized solar cell of the present invention (sample numbers 101 to 125), all of the metal complex dye represented by the formula (1) are represented by the formula (1) at a ratio that the isomer content satisfies the scope of the present invention. And a photoconductor layer adsorbed on semiconductor fine particles. In all of these dye-sensitized solar cells, the results of both the evaluation of the adsorption temperature dependency and the manufacturing variation satisfied the pass level. Therefore, even if the dye-sensitized solar cell of the present invention is manufactured under the same manufacturing conditions (production variation evaluation) or the adsorption temperature varies (adsorption temperature dependency evaluation), the photoelectric conversion efficiency varies. It was found to be small and show stable battery performance.
Moreover, as for the dye-sensitized solar cell (sample numbers 101-125) of this invention, all have the photoelectric conversion efficiency measured in said (evaluation of the manufacturing dispersion | variation in photoelectric conversion efficiency) in the level equivalent to patent documents 1 and 2. Yes, it had excellent photoelectric conversion efficiency.
Focusing on the isomers, the bond isomers were able to improve both the adsorption temperature dependence and production variability, and were particularly effective in improving the adsorption temperature dependence. On the other hand, the geometric isomers can improve both the adsorption temperature dependency and the production variation, and the effect of improving the production variation was particularly high. Moreover, even if these isomers coexisted, it was found that the adsorption temperature dependency and the production variation improvement effect were exhibited without inhibiting each other's action and function.

  In addition, the dye of the present invention containing the metal complex dye represented by the formula (1) at a ratio where the isomer content satisfies the scope of the present invention together with the isomer of the metal complex dye represented by the formula (1) The solution could be suitably used for the production of a dye-sensitized solar cell exhibiting the above excellent characteristics.

On the other hand, even in the dye-sensitized solar cell using the metal complex dye represented by the formula (1), the isomer content is less than 0.1 mol% or 50 mol% or more ( None of the sample numbers c01 to c04), the adsorption temperature dependency, and the manufacturing variability met the passing level of this test.
Also, isomer content of a dye-sensitized solar cell satisfying the scope of the present invention, a metal complex having a terpyridine ligand having the 4-position relative to the coordinating nitrogen atom of the substituent G ¹ of ruthenium When the dye (D-10) is used (sample number c05 to c07), the adsorption temperature dependency and production variation are reduced compared to the case where the metal complex dye not containing an isomer is used (sample number c01). None of them passed the pass level of this test.

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 (9)

A photoelectric conversion element having a conductive support, a photoreceptor layer containing an electrolyte, a charge transfer layer containing an electrolyte, and a counter electrode,
The photoreceptor layer has semiconductor fine particles carrying a metal complex dye represented by the following formula (1) and an isomer of the metal complex dye,
The isomer includes at least one of a bond isomer represented by the following formula (2) and a geometric isomer represented by the following formula (3);
The isomers less than 50 mol% der content of more than 0.1 mol% in total of the metal complex in the dye is, the content of the case containing the bond isomers is less than 0.5 mol% to 20 mol% The photoelectric conversion element whose content rate in the case of containing the said geometrical isomer is 0.5 mol% or more and less than 20 mol% .

In the formula, each M independently represents a hydrogen ion or a cation. X ¹ represents a nitrogen atom or CR ² . X ² represents a nitrogen atom when X ¹ is a nitrogen atom, and represents a nitrogen atom or CR ³ when X ¹ is CR ² . R ^{1 to} R ³ each independently represents a hydrogen atom, an alkyl group, a heteroaryl group, an aryl group, or a halogen atom. G ¹ represents a group represented by the following formula (G1).

In the formula, R ⁴ represents an alkyl group, an alkynyl group, an alkenyl group, an alkoxy group, an alkylthio group, an amino group, a heteroaryl group or an aryl group. R ⁵ represents a hydrogen atom, an alkyl group, an alkynyl group, an alkenyl group, an alkoxy group, an alkylthio group, an amino group, a heteroaryl group or an aryl group. m represents an integer of 1 to 3. n represents an integer of 0 to 2. Y ¹ represents an oxygen atom, a sulfur atom, NRf, a selenium atom, C (Rf) ₂ or Si (Rf) ₂ . Rf represents a hydrogen atom or an alkyl group. * Represents a bond to the pyridine ring in formula (1).   The photoelectric conversion element according to claim 1, wherein the content of the isomers is 0.3 mol% or more and less than 30 mol% in total.   X ² Is a nitrogen atom, The photoelectric conversion element of Claim 1 or 2.   The photoelectric conversion element according to claim 1, wherein n is 0.   Y ¹ Is a sulfur atom or an oxygen atom, The photoelectric conversion element of any one of Claims 1-4.   R ¹ Is an alkyl group or an aryl group, The photoelectric conversion element of any one of Claims 1-5.   R ⁵ Is an alkyl group, an alkynyl group, an alkenyl group, an alkoxy group, or an alkylthio group. The photoelectric conversion device according to any one of claims 1 to 6.   The dye-sensitized solar cell using the photoelectric conversion element of any one of Claims 1-7.   A dye solution containing a metal complex dye represented by the following formula (1), an isomer of the metal complex dye, and a solvent,
  The isomer includes at least one of a bond isomer represented by the following formula (2) and a geometric isomer represented by the following formula (3);
  The total content of the isomers in the metal complex dye is 0.1 mol% or more and less than 50 mol%, and the content when the bond isomer is contained is 0.5 mol% or more and less than 20 mol%. And a dye solution having a content of 0.5 mol% or more and less than 20 mol% when containing the geometric isomer.

  In the formula, each M independently represents a hydrogen ion or a cation. X ¹ Is a nitrogen atom or CR ² Represents. X ² X ¹ Represents a nitrogen atom, X represents ¹ Is CR ² In the case of nitrogen atom or CR ³ Represents. R ¹ ~ R ³ Each independently represents a hydrogen atom, an alkyl group, a heteroaryl group, an aryl group or a halogen atom. G ¹ Represents a group represented by the following formula (G1).

  Where R ⁴ Represents an alkyl group, an alkynyl group, an alkenyl group, an alkoxy group, an alkylthio group, an amino group, a heteroaryl group or an aryl group. R ⁵ Represents a hydrogen atom, an alkyl group, an alkynyl group, an alkenyl group, an alkoxy group, an alkylthio group, an amino group, a heteroaryl group or an aryl group. m represents an integer of 1 to 3. n represents an integer of 0 to 2. Y ¹ Is an oxygen atom, sulfur atom, NRf, selenium atom, C (Rf) ₂ Or Si (Rf) ₂ Represents. Rf represents a hydrogen atom or an alkyl group. * Represents a bond to the pyridine ring in formula (1).

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