JP2013072080A - Photoelectric conversion element, photoelectrochemical cell, and dye used for them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoelectric conversion element which achieves high performance, such as high photoelectric conversion efficiency, and also is excellent in IPCE (incident photon to current conversion efficiency) in a long-wavelength region and durability.SOLUTION: The photoelectric conversion element includes a laminated structure in which a photoreceptor including a layer of semiconductor fine particles onto which a dye has been adsorbed, a charge-transfer body, and a counter electrode are arranged on a conductive support, wherein a metal complex dye represented by the following formula (1): MLLX is used as the dye. In formula, M represents transition metal selected from ruthenium, osmium, iron, rhenium, and technetium; X represents NCS, Cl, Br, I, CN, NCO, HO, or NCN; Lrepresents a specific tridentate ligand; and Lrepresents a specific bidentate ligand.

Description

  The present invention relates to a photoelectric conversion element, a photoelectrochemical cell, and a dye used in these.

  Photoelectric conversion elements are used in various optical sensors, copying machines, solar cells, and the like. Various types of photoelectric conversion elements have been put to practical use, such as those using metals, semiconductors, organic pigments and dyes, or combinations thereof. Above all, a solar cell using non-depleting solar energy does not require fuel, and its full-scale practical use is expected as an inexhaustible clean energy. Among these, silicon solar cells have been researched and developed for a long time. It is spreading due to the policy considerations of each country. However, silicon is an inorganic material, and its throughput and molecular modification are naturally limited.

  Therefore, research on dye-sensitized solar cells has been vigorously conducted. In particular, it was the result of research by Graetzel of Lausanne University of Technology in Switzerland. They adopted a structure in which a dye composed of a ruthenium complex was fixed on the surface of a porous titanium oxide thin film, realizing conversion efficiency comparable to that of amorphous silicon. As a result, dye-sensitized solar cells have attracted a great deal of attention from researchers around the world.

  Patent Document 1 describes a dye-sensitized photoelectric conversion element using semiconductor fine particles sensitized with a ruthenium complex dye by applying this technique. Furthermore, the development of ruthenium complex-based sensitizing dyes continues to improve the photoelectric conversion efficiency (see Patent Documents 2 and 3).

US Pat. No. 5,463,057 US Patent Publication No. 2010/0258175 International Patent Publication No. 98/50393 Pamphlet

Devices with high photoelectric conversion efficiency have been provided by the techniques of Patent Documents 2 and 3 and the like. However, the present inventor is looking to play a part as a full-fledged source of green energy, and its performance is not sufficient, and development of photoelectric conversion elements that exhibit higher characteristics including improved durability Aimed at.
In view of the above-described present state of the present technical field, the present invention achieves high performance such as high photoelectric conversion efficiency, and also has a long wavelength region of IPCE (Incident Photon to Current Conversion Efficiency) and excellent durability. An object of the present invention is to provide chemical batteries and dyes used in them.

The above problem has been solved by the following means.
<1> A photoelectric conversion element having a laminated structure in which a photoconductor having a layer of semiconductor fine particles adsorbed with a dye, a charge transfer body, and a counter electrode are disposed on a conductive support, The photoelectric conversion element using the metal complex pigment | dye represented by following formula (1).
ML ¹ L ² X (1)
[Wherein M represents a transition metal selected from ruthenium, osmium, iron, rhenium, and technetium. X represents NCS ⁻ , Cl ⁻ , Br ⁻ , I ⁻ , CN ⁻ , NCO ⁻ , H ₂ O, or NCN ₂ ⁻ . L ¹ represents a tridentate ligand represented by the following formula (L1), and L ² represents a bidentate ligand represented by any of the following formulas (L2-1) to (L2-5). Represents. ]

［式（Ｌ１）において、Ｚａ、Ｚｂ及びＺｃはそれぞれ独立に、５又は６員環を形成しうる非金属原子群を表す。ただし、Ｚａ、Ｚｂ及びＺｃが形成する環のうち少なくとも１つは酸性基を有する。］

[In the formula (L1), Za, Zb and Zc each independently represent a nonmetallic atom group capable of forming a 5- or 6-membered ring. However, at least one of the rings formed by Za, Zb and Zc has an acidic group. ]

［式中、Ｇ^１は下記式（Ｇ１−１）〜（Ｇ１−６）のいずれかで表される構造を示し、Ｇ^２は、下記式（Ｇ２−１）〜（Ｇ２−３）のいずれかで表される構造を示す。Ｒは置換基を表す。ｎ１は０〜３の整数を表す。ｎ２は０〜５の整数を表す。］

[Wherein, G ¹ represents a structure represented by any of the following formulas (G1-1) to (G1-6), and G ² represents any of the following formulas (G2-1) to (G2-3): The structure represented by R represents a substituent. n1 represents an integer of 0 to 3. n2 represents an integer of 0 to 5. ]

［式中、Ｒ¹〜Ｒ^４は、水素原子、アルキル基、ヘテロアリール基、アリール基、ＣＯＯＨ、ＰＯ（ＯＨ）^２、ＰＯ（ＯＲ）（ＯＨ）、又はＣＯ（ＮＨＯＨ）を表す。ここでＲはアルキル基、ヘテロアリール基、又はアリール基を表す。＊は結合手を表す。］

[Wherein R ^{1 to} R ⁴ represent a hydrogen atom, an alkyl group, a heteroaryl group, an aryl group, COOH, PO (OH) ² , PO (OR) (OH), or CO (NHOH). Here, R represents an alkyl group, a heteroaryl group, or an aryl group. * Represents a bond. ]

<2> The photoelectric conversion element according to <1> , wherein L ² is represented by formula (L2-1) or (L2-2).
<3> The photoelectric conversion element according to <1> or <2>, in which the G ¹ is represented by (G1-1), (G1-2), or (G1-5).
<4> wherein ^{G 2} is (G2-1) or represented by (G2-2) <1> ~ photoelectric conversion device according to any one of <3>.
<5> The photoelectric conversion device according to any one of <1> to <4>, wherein the photoreceptor further contains a dye represented by the following formula (2).
MzL ³ _m3 L ⁴ _m4 Y _mY · CI (2)
[In Formula (2), Mz represents a metal atom. L ³ represents a ligand represented by the following formula (L3). L ⁴ represents a ligand represented by the following formula (L4). Y represents a monodentate or bidentate ligand. m3 represents an integer of 0 to 3. m4 represents an integer of 1 to 3. mY represents an integer of 0-2. CI represents a counter ion when a counter ion is required to neutralize the charge. ]

（式（Ｌ３）において、Ａｃは酸性基を表す。Ｒ^ａは置換基を表す。Ｒ^ｂはアルキル基又は芳香環基を表す。ｅ１及びｅ２は０〜５の整数を表す。Ｌ^ｃ及びＬ^ｄは共役鎖を表す。ｅ３は０又は１を表す。ｆは０〜３の整数を表す。ｇは０〜３の整数を表す。）

(In formula (L3), Ac represents an acidic group, R ^a represents ^a substituent, R ^b represents an alkyl group or an aromatic ring group, e1 and e2 represent an integer of 0 to 5. L ^c and L ^d represents a conjugated chain, e3 represents 0 or 1, f represents an integer of 0 to 3, and g represents an integer of 0 to 3.)

（式（Ｌ４）において、Ｚｄ、Ｚｅ及びＺｆは５又は６員環を形成しうる原子群を表す。ｈは０又は１を表す。ただし、Ｚｄ、Ｚｅ及びＺｆが形成する環のうち少なくとも１つは酸性基を有する。）

(In the formula (L4), Zd, Ze and Zf represent an atomic group capable of forming a 5- or 6-membered ring. H represents 0 or 1. However, at least one of the rings formed by Zd, Ze and Zf. One has an acidic group.)

<6> A photoelectrochemical cell using the photoelectric conversion element according to any one of <1> to <5>.
<7> A dye represented by the following general formula (1).
ML ¹ L ² X (1)
[Wherein M represents a transition metal selected from ruthenium, osmium, iron, rhenium, and technetium. X represents NCS ⁻ , Cl ⁻ , Br ⁻ , I ⁻ , CN ⁻ , NCO ⁻ , H ₂ O, or NCN ₂ ⁻ . L ¹ represents a tridentate ligand represented by the following formula (L1), and L ² represents a bidentate ligand represented by any of the following formulas (L2-1) to (L2-5). Represents.

式（Ｌ１）において、Ｚａ、Ｚｂ及びＺｃはそれぞれ独立に、５又は６員環を形成しうる非金属原子群を表す。ただし、Ｚａ、Ｚｂ及びＺｃが形成する環のうち少なくとも１つは酸性基を有する。

In the formula (L1), Za, Zb and Zc each independently represent a nonmetallic atom group capable of forming a 5- or 6-membered ring. However, at least one of the rings formed by Za, Zb and Zc has an acidic group.

式（Ｌ２−１）〜（Ｌ２−５）中、Ｇ^１は下記式（Ｇ１−１）〜（Ｇ１−６）のいずれかで表される構造を示し、Ｇ^２は、下記式（Ｇ２−１）〜（Ｇ２−３）のいずれかで表される構造を示す。

In formulas (L2-1) to (L2-5), G ¹ represents a structure represented by any of the following formulas (G1-1) to (G1-6), and G ² represents the following formula (G2- 1) A structure represented by any one of (G2-3) is shown.

式中、Ｒ¹〜Ｒ^３は、水素原子、アルキル基、ヘテロアリール基、アリール基、ＣＯＯＨ、ＰＯ（ＯＨ）_２、ＰＯ（ＯＲ）（ＯＨ）、又はＣＯ（ＮＨＯＨ）を表す。ここでＲはアルキル基、ヘテロアリール基、又はアリール基を表す。＊は結合手を表す。］

In the formula, R ^{1 to} R ³ represent a hydrogen atom, an alkyl group, a heteroaryl group, an aryl group, COOH, PO (OH) ₂ , PO (OR) (OH), or CO (NHOH). Here, R represents an alkyl group, a heteroaryl group, or an aryl group. * Represents a bond. ]

  The photoelectric conversion element and the photoelectrochemical cell using the dye of the present invention exhibit high performance such as high photoelectric conversion efficiency, high IPCE in the long wavelength region, and excellent durability.

It is sectional drawing shown typically about one embodiment of the photoelectric conversion element of this invention. 2 is a cross-sectional view schematically showing a dye-sensitized solar cell produced in Example 1. FIG. 3 is a cross-sectional view schematically showing a dye-sensitized solar cell produced in Example 2. FIG. It is sectional drawing which showed typically the modification of the photoelectric conversion element shown in FIG. 1 in the enlarged part (circle) about the dye-sensitized solar cell created in Example 3. FIG.

It has a structure in which terpyridine is coordinated to the central metal of the present invention, and thus, in a photoelectric conversion element, it exhibits high IPCE even in a long wavelength region exceeding 800 nm, realizes high photoelectric conversion efficiency, and further has high durability. Realized sex.
This reason includes unclear points, but can be explained as follows, including estimation. In other words, the type and position of the substituent on the nitrogen-containing 5-membered ring-pyridine ligand have different electronic and steric effects on the dye in the state of being adsorbed to titania via the nitrogen-containing 3-membered ring ligand. The substitution positions of the present invention are (1) a viewpoint of electron injection, (2) a viewpoint of recombination of electrons injected into titania, and (3) a viewpoint of suppression of dissociation (improvement of durability) of a dye due to the approach of water molecules. Therefore, it is thought that it had a positive influence. As a result, it is considered that both high photoelectric conversion efficiency and improved durability are realized. Hereinafter, the present invention will be described in detail based on preferred embodiments thereof.

[Element structure]
A preferred embodiment of a photoelectric conversion element that can use the dye of the present invention will be described with reference to the drawings. As shown in FIG. 1, the photoelectric conversion element 10 includes a conductive support 1, a photosensitive layer 2, a charge transfer layer 3, and a counter electrode 4 arranged in that order on the conductive support 1. The conductive support 1 and the photoreceptor 2 constitute a light receiving electrode 5. The photoreceptor 2 has conductive fine particles 22 and a sensitizing dye 21, and the dye 21 is adsorbed on the conductive fine particles 22 at least in part (the dye is in an adsorption equilibrium state, It may be present in the partial charge transfer layer.) The conductive support 1 on which the photoreceptor 2 is formed functions as a working electrode in the photoelectric conversion element 10. The photoelectric conversion element 10 can be operated as the photoelectrochemical cell 100 by causing the external circuit 6 to work.

The light-receiving electrode 5 is an electrode composed of a conductive support 1 and a photosensitive layer (semiconductor film) 2 including semiconductor fine particles 22 adsorbed with a dye 21 coated on the conductive support. Light incident on the photoreceptor layer (semiconductor film) 2 excites the dye. The excited dye has high energy electrons. Therefore, the electrons are transferred from the dye 21 to the conduction band of the semiconductor fine particles 22 and further reach the conductive support 1 by diffusion. At this time, the molecule of the dye 21 is an oxidant. While the electrons on the electrode work in the external circuit, the excited and oxidized dye receives electrons from the reducing agent (eg, I ⁻ ) in the electrolyte and returns to the ground state dye, thereby allowing the photoelectrochemical cell to Acts as At this time, the light receiving electrode 5 functions as a negative electrode of the battery.

The photoelectric conversion element of this embodiment has a photoreceptor having a layer of porous semiconductor fine particles on which an after-mentioned dye is adsorbed on a conductive support. At this time, a part of the dye dissociated in the electrolyte may be present. The photoreceptor is designed according to the purpose, and may have a single layer structure or a multilayer structure. The photoconductor of the photoelectric conversion element of the present embodiment includes semiconductor fine particles adsorbed with a specific sensitizing dye, has high sensitivity, and can be used as a photoelectrochemical cell, and high conversion efficiency can be obtained.
The upper and lower sides of the photoelectric conversion element do not need to be defined in particular, but in this specification, based on what is illustrated, the support body serving as the light receiving side with the counter electrode 4 side as the upper (top) direction The side of 1 is the lower (bottom) direction.

[Dye represented by Formula (1)]
The coloring matter of the present invention is represented by the following formula (1).
ML ¹ L ² X (1)

* M
In the formula, M represents a transition metal selected from ruthenium, osmium, iron, rhenium, and technetium. Of these, ruthenium is preferable.

* X
X represents NCS ⁻ , Cl ⁻ , Br ⁻ , I ⁻ , CN ⁻ , NCO ⁻ , H ₂ O, or NCN ₂ ⁻ .

* L ¹
L ¹ is represented by the following formula (L1).

  In the formula (L1), Za, Zb and Zc each independently represent a nonmetallic atom group capable of forming a 5- or 6-membered ring. However, at least one of the rings formed by Za, Zb and Zc has an acidic group.

・ Za, Zb, Zc
Za, Zb and Zc each independently represent a nonmetallic atom group capable of forming a 5-membered ring or a 6-membered ring. The formed 5-membered or 6-membered ring may be substituted or unsubstituted, and may be monocyclic or condensed. Za, Zb and Zc are preferably composed of a carbon atom, a hydrogen atom, a nitrogen atom, an oxygen atom, a sulfur atom, a phosphorus atom and / or a halogen atom, and preferably form an aromatic ring. In the case of a 5-membered ring, an imidazole ring, an oxazole ring, a thiazole ring or a triazole ring is preferably formed. In the case of a 6-membered ring, a pyridine ring, a pyrimidine ring, a pyridazine ring or a pyrazine ring is preferably formed. Of these, an imidazole ring or a pyridine ring is more preferable.

Acidic group In the present invention, an acidic group is a substituent having a dissociative proton, such as a carboxy group, a phosphonyl group, a phosphoryl group, a sulfo group, a boric acid group, or a group having any one of these. Preferably, it is a carboxy group or a group having this. Further, the acidic group may take a form of releasing a proton and dissociating, or may be a salt. The acidic group is preferably a carboxy group, a sulfonic acid group, a phosphonyl group, a phosphoryl group, or a salt thereof. The acidic group may be a group bonded through a linking group. For example, a carboxyvinylene group, a dicarboxyvinylene group, a cyanocarboxyvinylene group, a carboxyphenyl group, and the like can be mentioned as preferable examples. In addition, the acidic group mentioned here and its preferable range may be called acidic group Ac. In addition, as above-mentioned, acidic group Ac should just be a group which has group which shows acidity, in other words, group which shows acidity may be introduce | transduced via the predetermined | prescribed coupling group. The acidic group may exist as a salt thereof. Although it does not specifically limit as a counter ion when it becomes a salt, For example, the example of the positive ion in the counter ion CI of following formula (2) is mentioned.
As the acidic group that at least one of the rings formed by Za, Zb, and Zc has, COOH, PO (OH) ₂ , PO (OR) (OH), or CO (NHOH) is preferable, and more preferably, COOH, PO (OH) ₂ or PO (OR) (OH), particularly preferably COOH. Here, R represents an alkyl group, a heteroaryl group, or an aryl group.

* L ²
L ² has the formula (L2-1), (L2-2), (L2-3), represented by (L2-4), or (L2-5). Of the formulas (L2-1) to (L2-5), the formula (L2-1), (L2-2), (L2-4), or (L2-5) is preferable, and more preferably, Formula (L2-1) or (L2-2), particularly preferably Formula (L2-1).

・ G1
G1 represents a structure represented by the following formulas (G1-1) to (G1-6). Of (G1-1) to (G1-6), (G1-1), (G1-2), (G1-3), (G1-5), or (G1-6) is preferable. More preferred is (G1-1), (G1-2), (G1-5), or (G1-6), and particularly preferred is (G1-1), (G1-2) or (G1- 5).
・ G2
G2 represents a structure represented by the following formulas (G2-1) to (G2-3). Of (G2-1) to (G2-3), preferably (G2-1) or (G2-2), and more preferably (G2-2).

・Ｒ^１〜Ｒ^４
Ｒ^１、Ｒ^２、Ｒ^３、及びＲ^４は、水素原子、アルキル基、ヘテロアリール基、アリール基、ＣＯＯＨ、ＰＯ（ＯＨ）_２、ＰＯ（ＯＲ）（ＯＨ）、又はＣＯ（ＮＨＯＨ）を表す。ここでＲはアルキル基、ヘテロアリール基、又はアリール基を表す。
Ｒ^１〜Ｒ^３として好ましくは、水素原子又はアルキル基であり、特に好ましくは、電子吸引性基が置換したアルキル基である。
Ｒ^４として好ましくは、水素原子、アルキル基、ヘテロアリール基、又はアリール基であり、より好ましくは、アルキル基、ヘテロアリール基、又はアリール基であり、更に好ましくは、アルキル基、又はアリール基であり、特に好ましくは、アルキル基である。

· ^R 1 ~R ⁴
R ¹ , R ² , R ³ , and R ⁴ represent a hydrogen atom, an alkyl group, a heteroaryl group, an aryl group, COOH, PO (OH) ₂ , PO (OR) (OH), or CO (NHOH). . Here, R represents an alkyl group, a heteroaryl group, or an aryl group.
R ^{1 to} R ³ are preferably a hydrogen atom or an alkyl group, and particularly preferably an alkyl group substituted with an electron-withdrawing group.
R ⁴ is preferably a hydrogen atom, an alkyl group, a heteroaryl group, or an aryl group, more preferably an alkyl group, a heteroaryl group, or an aryl group, and still more preferably an alkyl group or an aryl group. And particularly preferably an alkyl group.

  The pigment represented by the formula (1) has a maximum absorption wavelength in an ethanol solution of preferably 500 to 700 nm, more preferably 550 to 650 nm.

  Although the preferable specific example of the pigment | dye represented by Formula (1) of this invention below is shown, this invention is not limited to this.

(Dye made of compound of formula (2))
In the photoelectric conversion element and the photoelectrochemical cell of the present invention, it is preferable to use in combination with another metal complex dye. By using together with other metal complex dyes, the mutual adsorption state can be controlled, and higher efficiency and durability than each can be achieved. In this case, the photoelectric conversion layers containing the semiconductor fine particles sensitized by the two kinds of sensitizing dyes can be formed as separate layers.

It is preferable that the other metal complex dye includes a dye made of a compound represented by the following formula (2).
MzL ³ _m3 L ⁴ _m4 Y _mY · CI (2)

・ Metal atom Mz
Mz is synonymous with M in Formula (1).

* L ³ (Formula (L3))
L ³ represents a bidentate ligand represented by the following formula (L3).

・ M3
m3 is an integer of 0 to 3, preferably 1 to 3, and more preferably 1. When m3 is 2 or more, L ³ may be the same or different.

・ Ac
Each Ac independently represents an acidic group. The preferable thing of Ac is synonymous with what was defined by Formula (1). Ac may be substituted on the pyridine ring or any atom of the substituent.

・ R ^a
R ^a each independently represents a substituent, and an example of the substituent T can be given. Preferably an alkyl group, alkenyl group, cycloalkyl group, aryl group, heterocyclic group, alkoxy group, aryloxy group, alkoxycarbonyl group, amino group, acyl group, sulfonamido group, acyloxy group, carbamoyl group, acylamino group, cyano Group or a halogen atom, more preferably an alkyl group, an alkenyl group, an aryl group, a heterocyclic group, an alkoxy group, an alkoxycarbonyl group, an amino group, an acylamino group or a halogen atom, particularly preferably an alkyl group, an alkenyl group, An alkoxy group, an alkoxycarbonyl group, an amino group, or an acylamino group.

・ R ^b
R ^b represents an alkyl group or an aromatic ring group. The aromatic group is preferably an aromatic group having 6 to 30 carbon atoms, such as phenyl, substituted phenyl, naphthyl, and substituted naphthyl. The heterocyclic group is preferably a heterocyclic group having 1 to 30 carbon atoms such as 2-thienyl, 2-pyrrolyl, 2-imidazolyl, 1-imidazolyl, 4-pyridyl, 3-indolyl and the like. Is a combination of two or more. Preferred is a heterocyclic group having 1 to 3 electron donating groups, and more preferred is a group in which two or more of thienyl and thienyl are linked. The electron donating group is preferably an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, an alkoxy group, an aryloxy group, an amino group, an acylamino group or a hydroxy group, and an alkyl group, an alkoxy group, an amino group or a hydroxy group. Is more preferable, and an alkyl group is particularly preferable.

・ E1, e2
e1 and e2 are integers of 0 to 5, preferably 0 to 3, and more preferably 0 to 2.

L ^c and L ^d
L ^c and L ^d each independently represent a conjugated chain, and represent a conjugated chain composed of an arylene group, a heteroarylene group, an ethenylene group and / or an ethynylene group. The ethenylene group, ethynylene group, and the like may be unsubstituted or substituted. When the ethenylene group has a substituent, the substituent is preferably an alkyl group, and more preferably methyl. L ^c and L ^d are each independently preferably a conjugated chain having 2 to 6 carbon atoms, more preferably thiophenediyl, ethenylene, butadienylene, ethynylene, butadienylene, methylethenylene or dimethylethenylene, Butadienylene is particularly preferred and ethenylene is most preferred. L ^c and L ^d may be the same or different, but are preferably the same. When the conjugated chain includes a carbon-carbon double bond, each double bond may be E-type or Z-type, or a mixture thereof.

・ E3
e3 is 0 or 1. In particular, when e3 is 0, the right f in the formula is preferably 1 or 2, and when e3 is 1, the right f is preferably 0 or 1. The total sum of f is preferably an integer of 0-2.

・ G
g represents the integer of 0-3 each independently, and it is preferable that it is an integer of 0-2.

・ F
f represents the integer of 0-3 each independently. When the sum of f is 1 or more and the ligand L ³ has at least one acidic group, m3 in the formula (2) is preferably 2 or 3, more preferably 2. . When f is 2 or more, Ac may be the same or different. In the formula, f on the left side is preferably 0 or 1, and f on the right side is preferably an integer of 0 to 2.

The ligand L ³ in the formula (2) is preferably represented by the following general formula (L3-1), (L3-2) or (L3-3).

  In the formula, Ac, Ra, f, g and e3 have the same meanings as in the general formula (L3). However, Ra substituted at the N-position may be a hydrogen atom. e4 is an integer of 0-4.

* L ⁴ (Formula (L4))
L ⁴ represents a bidentate or tridentate ligand represented by the following formula (L4).

In the formula (L4), Zd, Ze, and Zf represent an atomic group that can form a 5- or 6-membered ring. h represents 0 or 1; However, at least one of the rings formed by Zd, Ze, and Zf has an acidic group.
・ M4
m4 is an integer of 1 to 3, and preferably 1 or 2. m4 is the L ⁴ when two or more may be the same or different.

・ Zd, Ze, Zf
Zd, Ze, and Zf are synonymous with Za, Zb, and Zc of Formula (1).

・ H
h represents 0 or 1; h is preferably 0, and L ⁴ is preferably a bidentate ligand.

Ligand ^{L 4} represents is preferably represented by any of the following formulas (L4-1) ~ (L4-8), the formula (L4-1), (L4-2), (L4-4), Or more preferably represented by (L4-6), particularly preferably represented by formula (L4-1) or (L4-2), and particularly preferably represented by formula (L4-1). .

  In formula, Ac represents an acidic group or its salt each independently. Ac is synonymous with Ac defined above.

In formula, ^Ra is synonymous with Formula (1). However, R ^a substituted at the N-position may be ^a hydrogen atom.

i independently represents the number of carbon positions (integer) that can be substituted by 0 or more. The number of possible substitutions is indicated by () next to the formula number. R ^a may be linked to each other or condensed to form a ring.

In the above formulas L4-1 to L4-8, the substituent Ra is shown with a bond extended to ^a predetermined aromatic ring, but is not limited to those substituted with the aromatic ring. That is, for example, in Formula L4-1, Ac and R ^a are substituted on the left pyridine ring, but these may be substituted on the right pyridine ring.

* Ligand Y
In formula (2), Y represents a monodentate or bidentate ligand. mY represents the number of ligands Y. mY represents an integer of 0 to 2, and mY is preferably 1 or 2. When Y is a monodentate ligand, mY is preferably 2. When Y is a bidentate ligand, mY is preferably 1. When mY is 2 or more, Y may be the same or different, and Y may be connected to each other.

  Ligand Y is preferably acyloxy group, thioacylthio group, acylaminooxy group, dithiocarbamate group, dithiocarbonate group, trithiocarbonate group, thiocyanate group, isothiocyanate group, cyanate group, isocyanate group, cyano group, A ligand coordinated by a group selected from the group consisting of an alkylthio group, an arylthio group, an alkoxy group and an aryloxy group, or a ligand composed of a halogen atom, carbonyl, 1,3-diketone or thiourea. More preferably, a ligand coordinated by a group selected from the group consisting of acyloxy group, acylaminooxy group, dithiocarbamate group, thiocyanate group, isothiocyanate group, cyanate group, isocyanate group, cyano group or arylthio group, or A ligand comprising a halogen atom, 1,3-diketone or thiourea, particularly preferably coordinated with a group selected from the group consisting of a dithiocarbamate group, a thiocyanate group, an isothiocyanate group, a cyanate group and an isocyanate group. A ligand or a ligand comprising a halogen atom or a 1,3-diketone, most preferably a ligand coordinated by a group selected from the group consisting of a dithiocarbamate group, a thiocyanate group and an isothiocyanate group Or a ligand comprising 1,3-diketone A. In addition, when the ligand Y contains an alkyl group, an alkenyl group, an alkynyl group, an alkylene group or the like, these may be linear or branched, and may be substituted or unsubstituted. Moreover, when an aryl group, a heterocyclic group, a cycloalkyl group, etc. are included, they may be substituted or unsubstituted, and may be monocyclic or condensed.

  When Y is a bidentate ligand, Y is an acyloxy group, acylthio group, thioacyloxy group, thioacylthio group, acylaminooxy group, thiocarbamate group, dithiocarbamate group, thiocarbonate group, dithiocarbonate group, trithio A ligand coordinated by a group selected from the group consisting of a carbonate group, an acyl group, an alkylthio group, an arylthio group, an alkoxy group and an aryloxy group, or a 1,3-diketone, carbonamide, thiocarbonamide, or thio A ligand composed of urea is preferable. When Y is a monodentate ligand, Y is a ligand coordinated by a group selected from the group consisting of a thiocyanate group, an isothiocyanate group, a cyanate group, an isocyanate group, a cyano group, an alkylthio group, and an arylthio group, or A ligand composed of a halogen atom, carbonyl, dialkyl ketone, or thiourea is preferred.

* Counter ion CI
CI in Formula (1) represents a counter ion when a counter ion is required to neutralize the charge. In general, whether a dye is a cation or an anion or has a net ionic charge depends on the metal, ligand and substituent in the dye.
The dye of formula (1) may be dissociated and have a negative charge, for example, because the substituent has a dissociable group. In this case, the overall charge of the dye of formula (1) is neutralized by CI.

When the counter ion CI is a positive counter ion, for example, the counter ion CI is an inorganic or organic ammonium ion (for example, tetraalkylammonium ion, pyridinium ion, etc.), an alkali metal ion, or a proton.
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, halogen anions (eg, fluoride ions, chloride ions, bromide ions, iodide ions, etc.), substituted aryl sulfonate ions (eg, p-toluene sulfonate ions, p-chlorobenzene sulfonate ions, etc.), aryl disulfones Acid ion (for example, 1,3-benzenedisulfonic acid ion, 1,5-naphthalenedisulfonic acid ion, 2,6-naphthalenedisulfonic acid ion, etc.), alkyl sulfate ion (for example, methyl sulfate ion, etc.), sulfate ion, thiocyanate ion Perchlorate ion, tetrafluoroborate ion, hexafluorophosphate ion, picrate ion, acetate ion, trifluoromethanesulfonate ion and the like. Further, as the charge balance counter ion, an ionic polymer or another dye having a charge opposite to that of the dye may be used, and a metal complex ion (for example, bisbenzene-1,2-dithiolatonickel (III)) can also be used. is there.

* Bonding group The dye having the structure represented by the formula (2) preferably has at least one suitable bonding group for the surface of the semiconductor fine particles. It is more preferable to have 1 to 6 bonding groups in the dye, and it is particularly preferable to have 1 to 4 bonding groups. Examples of the linking group include the aforementioned Ac.

  Specific examples of the dye having the structure represented by the formula (2) are shown below, but the present invention is not limited thereto. In addition, when the pigment | dye in the following specific example contains the ligand which has a proton dissociable group, this ligand may dissociate as needed and may discharge | release a proton.

The dye represented by the formula (2) can be synthesized with reference to Japanese Patent Application Laid-Open No. 2001-291534 and the method cited in the publication.
The dye comprising the compound represented by formula (2) has a maximum absorption wavelength in the solution of preferably 300 to 1000 nm, more preferably 350 to 950 nm, and particularly preferably 370 to 900 nm. It is.
In the photoelectric conversion element and the photoelectrochemical cell of the present invention, a dye having a wide wavelength range can be obtained by using a dye composed of at least the compound represented by the formula (1) and a dye composed of the compound represented by the formula (2). By using light, high conversion efficiency can be ensured.

  The preferred compounding ratio of the metal complex dye having the structure represented by the formula (2) and the dye having the structure represented by the formula (1) is R / (R) and S / (the latter). S = 90/10 to 10/90, preferably R / S = 80/20 to 20/80, more preferably R / S = 70/30 to 30/70, even more preferably R / S = 60/40 -40/60, most preferably R / S = 55 / 45-45 / 55, usually equimolar amounts of both.

  In addition, in this specification, about the display of a compound (a complex and a pigment | dye are included), it uses for the meaning containing the salt itself, a complex, and its ion besides the said compound itself. Moreover, it is the meaning including the derivative modified with the predetermined form in the range with the desired effect. In addition, in the present specification, a substituent (including a linking group and a ligand) for which substitution / non-substitution is not specified means that the group may have an arbitrary substituent. This is also synonymous for compounds that do not specify substitution / non-substitution. Preferred substituents include the following substituent T.

Examples of the substituent T include the following.
An alkyl group (preferably an alkyl group having 1 to 20 carbon atoms, such as methyl, ethyl, isopropyl, t-butyl, pentyl, heptyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl, etc.), alkenyl A group (preferably an alkenyl group having 2 to 20 carbon atoms, such as vinyl, allyl, oleyl, etc.), an alkynyl group (preferably an alkynyl group having 2 to 20 carbon atoms, such as ethynyl, butadiynyl, phenylethynyl, etc.), A cycloalkyl group (preferably a cycloalkyl group having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc.), an aryl group (preferably an aryl group having 6 to 26 carbon atoms, for example, Phenyl, 1-naphthyl, 4-methoxyphenyl, -Chlorophenyl, 3-methylphenyl, etc.), heterocyclic groups (preferably heterocyclic groups having 2 to 20 carbon atoms, such as 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2 -Oxazolyl etc.), an alkoxy group (preferably an alkoxy group having 1 to 20 carbon atoms, such as methoxy, ethoxy, isopropyloxy, benzyloxy etc.), an aryloxy group (preferably an aryloxy group having 6 to 26 carbon atoms) , For example, phenoxy, 1-naphthyloxy, 3-methylphenoxy, 4-methoxyphenoxy, etc.), alkoxycarbonyl groups (preferably C2-C20 alkoxycarbonyl groups such as ethoxycarbonyl, 2-ethylhexyloxycarbonyl, etc.) ), Amino group (preferably carbon Amino group having 0 to 20 children, such as amino, N, N-dimethylamino, N, N-diethylamino, N-ethylamino, anilino, etc.), sulfonamide group (preferably sulfonamide having 0 to 20 carbon atoms) A group such as N, N-dimethylsulfonamide, N-phenylsulfonamide, etc., an acyloxy group (preferably an acyloxy group having 1 to 20 carbon atoms such as acetyloxy, benzoyloxy, etc.), a carbamoyl group (preferably A carbamoyl group having 1 to 20 carbon atoms, such as N, N-dimethylcarbamoyl, N-phenylcarbamoyl, etc.), an acylamino group (preferably an acylamino group having 1 to 20 carbon atoms, such as acetylamino, benzoylamino, etc.) , A cyano group, or a halogen atom (eg, fluorine atom, chlorine atom, bromine atom) More preferably an alkyl group, alkenyl group, aryl group, heterocyclic group, alkoxy group, aryloxy group, alkoxycarbonyl group, amino group, acylamino group, cyano group or halogen atom, Particularly preferred are an alkyl group, an alkenyl group, a heterocyclic group, an alkoxy group, an alkoxycarbonyl group, an amino group, an acylamino group, and a 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. When an aryl group, a heterocyclic group, or the like is included, they may be monocyclic or condensed, and may be substituted or unsubstituted.

[Photoelectric conversion element]
(Photoreceptor layer)
The embodiment of the photoelectric conversion element has already been described with reference to FIG. In the present embodiment, the photoreceptor layer 2 is composed of a porous semiconductor layer composed of a layer of semiconductor fine particles 22 on which a dye described later is adsorbed. This dye may be partially dissociated in the electrolyte. The photoreceptor layer 2 may be designed according to the purpose and may have a multilayer structure.
As described above, since the photosensitive layer 2 includes the semiconductor fine particles 22 on which a specific dye is adsorbed, the light receiving sensitivity is high, and when used as the photoelectrochemical cell 100, high photoelectric conversion efficiency can be obtained. Furthermore, it has high durability.

(Charge transfer body)
The electrolyte composition used for the photoelectric conversion element 10 of the present invention includes, for example, a combination of iodine and iodide (for example, lithium iodide, tetrabutylammonium iodide, tetrapropylammonium iodide, etc.) as an oxidation-reduction pair, alkyl Combinations of viologens (for example, methyl viologen chloride, hexyl viologen bromide, benzyl viologen tetrafluoroborate) and reduced forms thereof, combinations of polyhydroxybenzenes (for example, hydroquinone, naphthohydroquinone, etc.) and oxidized forms thereof, bivalent and trivalent And a combination of iron complexes (for example, red blood salt and yellow blood salt). Of these, a combination of iodine and iodide is preferred.

  The cation of the iodine salt is preferably a 5-membered or 6-membered nitrogen-containing aromatic cation. In particular, when the compound represented by the general formula (1) is not an iodine salt, republished WO95 / 18456, JP-A-8-259543, Electrochemistry, Vol.65, No.11, p.923 (1997) It is preferable to use iodine salts such as pyridinium salts, imidazolium salts, and triazolium salts described in the above.

  The electrolyte composition used for the photoelectric conversion element 10 of the present invention preferably contains iodine together with the heterocyclic quaternary salt compound. The iodine content is preferably 0.1 to 20% by mass, and more preferably 0.5 to 5% by mass with respect to the entire electrolyte composition.

  The electrolyte composition used for the photoelectric conversion element 10 of the present invention may contain a solvent. The content of the solvent in the electrolyte composition is preferably 50% by mass or less, more preferably 30% by mass or less, and particularly preferably 10% by mass or less based on the entire composition.

  Further, as the electrolyte of the present invention, a charge transport layer containing a hole conductor material may be used. As the hole conductor material, a 9,9'-spirobifluorene derivative or the like can be used.

  In addition, an electrode layer, a photoreceptor layer (photoelectric conversion layer), a charge transfer layer (hole transport layer), a conductive layer, and a counter electrode layer can be sequentially stacked. A hole transport material that functions as a p-type semiconductor can be used as the hole transport layer. As a preferred hole transport layer, for example, an inorganic or organic hole transport material can be used. Examples of the inorganic hole transport material include CuI, CuO, and NiO. Examples of the organic hole transport material include high molecular weight materials and low molecular weight materials, and examples of the high molecular weight materials include polyvinyl carbazole, polyamine, and organic polysilane. Moreover, as a low molecular weight thing, a triphenylamine derivative, a stilbene derivative, a hydrazone derivative, a phenamine derivative etc. are mentioned, for example. Among these, organic polysilanes are preferable because, unlike conventional carbon-based polymers, σ electrons delocalized along the main chain Si contribute to photoconductivity and have high hole mobility (Phys. Rev.). B, 35, 2818 (1987)).

(Conductive support)
As shown in FIG. 1, in the photoelectric conversion element of the present invention, a photosensitive layer 2 in which a sensitizing dye 21 is adsorbed on porous semiconductor fine particles 22 is formed on a conductive support 1. As will be described later, for example, the photoreceptor layer 2 can be produced by immersing the dispersion of semiconductor fine particles in the dye solution of the present invention after coating and drying on a conductive support.

As the conductive support 1, glass or a polymer material having a conductive film on the surface can be used as the support itself, such as metal. The conductive support 1 is preferably substantially transparent. Substantially transparent means that the light transmittance is 10% or more, preferably 50% or more, particularly preferably 80% or more. As the conductive support 1, a glass or polymer material coated with a conductive metal oxide can be used. The coating amount of the conductive metal oxide at this time is preferably 0.1 to 100 g per 1 m ² of the support of glass or polymer material. When a transparent conductive support is used, light is preferably incident from the support side. Examples of polymer materials that are preferably used include triacetyl cellulose (TAC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), syndiotactic polystyrene (SPS), polyphenylene sulfide (PPS), polycarbonate (PC), Examples include polyarylate (PAR), polysulfone (PSF), polyester sulfone (PES), polyetherimide (PEI), cyclic polyolefin, and brominated phenoxy. On the conductive support 1, the surface may be provided with a light management function. For example, an antireflection film in which high refractive films and low refractive index oxide films described in JP-A-2003-123859 are alternately laminated, The light guide function described in JP-A-2002-260746 is improved.

  In addition to this, a metal support can also be preferably used. Examples thereof include titanium, aluminum, copper, nickel, iron, stainless steel, and copper. These metals may be alloys. More preferably, titanium, aluminum, and copper are preferable, and titanium and aluminum are particularly preferable.

(Semiconductor fine particle dispersion)
In the present invention, the semiconductor fine particle dispersion having a solid content other than the semiconductor fine particles of 10% by mass or less of the whole of the semiconductor fine particle dispersion is applied to the conductive support 1 and heated appropriately. Quality semiconductor fine particle coating layer can be obtained.

  In addition to the sol-gel method, semiconductor fine particle dispersions can be prepared by depositing fine particles in a solvent and using them as they are when synthesizing semiconductors. Or a method of pulverizing and grinding mechanically using a mill or a mortar. As the dispersion solvent, one or more of water and various organic solvents can be used. Examples of the organic solvent include alcohols such as methanol, ethanol, isopropyl alcohol, citronellol and terpineol, ketones such as acetone, esters such as ethyl acetate, dichloromethane, acetonitrile and the like.

  At the time of dispersion, a small amount of, for example, a polymer such as polyethylene glycol, hydroxyethyl cellulose, carboxymethyl cellulose, a surfactant, an acid, or a chelating agent may be used as a dispersion aid. However, most of these dispersing aids are preferably removed by a filtration method, a method using a separation membrane, a centrifugal method or the like before the step of forming a film on a conductive support. In the semiconductor fine particle dispersion, the solid content other than the semiconductor fine particles can be 10% by mass or less of the total dispersion. This concentration is preferably 5% or less, more preferably 3% or less, and particularly preferably 1% or less. More preferably, it is 0.5% or less, and particularly preferably 0.2%. That is, in the semiconductor fine particle dispersion, the solid content other than the solvent and the semiconductor fine particles can be 10% by mass or less of the entire semiconductor fine dispersion. It is preferable to consist essentially of semiconductor fine particles and a dispersion solvent.

If the viscosity of the semiconductor fine particle dispersion is too high, the dispersion will aggregate and cannot be formed into a film. Conversely, if the viscosity of the semiconductor fine particle dispersion is too low, the liquid will flow and cannot be formed into a film. is there. Therefore, the viscosity of the dispersion is preferably 10 to 300 N · s / m ² at 25 ° C. More preferably, it is 50 to 200 N · s / m ² at 25 ° C.

  As a coating method of the semiconductor fine particle dispersion, a regular coating such as a roller method or a dip method can be used as an application method. Moreover, an air knife method, a blade method, etc. can be used as a metering method.

The preferred thickness of the entire semiconductor fine particle layer is 0.1 μm to 100 μm. The thickness of the semiconductor fine particle layer is further preferably 1 μm to 30 μm, and more preferably 2 μm to 25 μm. The amount of the semiconductor fine particles supported per 1 m ² of the support is preferably 0.5 g to 400 g, and more preferably 5 g to 100 g. The method for forming the film by applying the fine particle dispersion is not particularly limited, and a known method may be applied as appropriate.

The total amount of the sensitizing dye 21 used is preferably from 0.01 mmol to 100 mmol, more preferably from 0.1 mmol to 50 mmol, and particularly preferably from 0.1 mmol to 10 mmol, per 1 m ² of the support. . In this case, the amount of the sensitizing dye 21 according to the present invention is preferably 5 mol% or more. Further, the adsorption amount of the sensitizing dye 21 to the semiconductor fine particles 22 is preferably 0.001 mmol to 1 mmol, more preferably 0.1 to 0.5 mmol, with respect to 1 g of the semiconductor fine particles. By using such a dye amount, a sensitizing effect in a semiconductor can be sufficiently obtained. On the other hand, when the amount of the dye is small, the sensitizing effect is insufficient, and when the amount of the dye is too large, the dye not attached to the semiconductor floats and causes the sensitizing effect to be reduced.

(Counter electrode)
The counter electrode 4 functions as a positive electrode of the photoelectrochemical cell. The counter electrode 4 is usually synonymous with the conductive support 1 described above, but a support for the counter electrode is not necessarily required in a configuration in which the strength is sufficiently maintained. However, having a support is advantageous in terms of hermeticity. Examples of the material for the counter electrode 4 include platinum, carbon, and conductive polymer. Preferable examples include platinum, carbon, and conductive polymer. The structure of the counter electrode 4 is preferably a structure having a high current collecting effect. Preferable examples include JP-A-10-505192.

(Reception electrode)
The light receiving electrode 5 may be a tandem type in order to increase the utilization rate of incident light. Preferred examples of the tandem type configuration include those described in JP-A Nos. 2000-90989 and 2002-90989. A light management function for efficiently performing light scattering and reflection inside the layer of the light receiving electrode 5 may be provided. Preferably, the thing of Unexamined-Japanese-Patent No. 2002-93476 is mentioned.

  It is preferable to form a short-circuit prevention layer between the conductive support 1 and the porous semiconductor fine particle layer in order to prevent a reverse current due to direct contact between the electrolyte and the electrode. Preferable examples include Japanese Patent Application Laid-Open No. 06-507999. In order to prevent contact between the light receiving electrode 5 and the counter electrode 4, it is preferable to use a spacer or a separator. A preferable example is JP-A No. 2001-283941.

  Cell and module sealing methods include polyisobutylene thermosetting resin, novolak resin, photo-curing (meth) acrylate resin, epoxy resin, ionomer resin, glass frit, method using aluminum alkoxide for alumina, low melting point glass paste It is preferable to use a laser melting method. When glass frit is used, powder glass mixed with acrylic resin as a binder may be used.

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

<Example of dye synthesis>
Intermediate D4-5 was synthesized via the route shown in Scheme 1.

Intermediate D4-5 was used in the literature Chem. Commun. , 2009, 5844. Dye 4 was synthesized.
Similarly, Dye 1 to Dye 3 and Dye 5 to Dye 11 were synthesized.

Example 1
Various pastes for forming the semiconductor layer or light scattering layer of the semiconductor electrode constituting the photoelectrode were prepared, and dye-sensitized solar cells were prepared using this paste.
[Preparation of paste]
First, a paste for forming a semiconductor layer or a light scattering layer of a semiconductor electrode constituting a photoelectrode was prepared with the composition shown in Table A below. In the following preparation, TiO ₂ was put in a medium and stirred to prepare a slurry, and a thickener was added thereto and kneaded to obtain a paste.

ＴｉＯ_２粒子１：アナターゼ、平均粒径；２５ｎｍ
ＴｉＯ_２粒子２：アナターゼ、平均粒径；２００ｎｍ
棒状ＴｉＯ_２粒子Ｓ１：アナターゼ、直径；１００ｎｍ、アスペクト比；５
棒状ＴｉＯ_２粒子Ｓ２：アナターゼ、直径；３０ｎｍ、アスペクト比；６．３
棒状ＴｉＯ_２粒子Ｓ３：アナターゼ、直径；５０ｎｍ、アスペクト比；６．１
棒状ＴｉＯ_２粒子Ｓ４：アナターゼ、直径；７５ｎｍ、アスペクト比；５．８
棒状ＴｉＯ_２粒子Ｓ５：アナターゼ、直径；１３０ｎｍ、アスペクト比；５．２
棒状ＴｉＯ_２粒子Ｓ６：アナターゼ、直径；１８０ｎｍ、アスペクト比；５
棒状ＴｉＯ_２粒子Ｓ７：アナターゼ、直径；２４０ｎｍ、アスペクト比；５
棒状ＴｉＯ_２粒子Ｓ８：アナターゼ、直径；１１０ｎｍ、アスペクト比；４．１
棒状ＴｉＯ_２粒子Ｓ９：アナターゼ、直径；１０５ｎｍ、アスペクト比；３．４
板状マイカ粒子Ｐ１ ：直径；１００ｎｍ、アスペクト比；６
ＣＢ：セルロース系バインダー

TiO ₂ particles 1: anatase, average particle size; 25 nm
TiO ₂ particles 2: anatase, average particle size; 200 nm
Rod-like TiO ₂ particles S1: anatase, diameter: 100 nm, aspect ratio: 5
Rod-like TiO ₂ particles S2: anatase, diameter: 30 nm, aspect ratio: 6.3
Rod-like TiO ₂ particles S3: anatase, diameter: 50 nm, aspect ratio: 6.1
Rod-like TiO ₂ particles S4: anatase, diameter: 75 nm, aspect ratio: 5.8
Rod-like TiO ₂ particles S5: anatase, diameter: 130 nm, aspect ratio: 5.2
Rod-like TiO ₂ particles S6: anatase, diameter; 180 nm, aspect ratio: 5
Rod-like TiO ₂ particles S7: anatase, diameter; 240 nm, aspect ratio: 5
Rod-like TiO ₂ particles S8: anatase, diameter: 110 nm, aspect ratio: 4.1
Rod-like TiO ₂ particles S9: anatase, diameter: 105 nm, aspect ratio: 3.4
Plate-like mica particles P1: diameter: 100 nm, aspect ratio: 6
CB: Cellulosic binder

  A photoelectrode having the same configuration as that of the photoelectrode 12 shown in FIG. 5 described in JP-A-2002-289274 is prepared by the following procedure, and the photoelectrode shown in FIG. A 10 × 10 mm scale dye-sensitized solar cell 1 having the same configuration as that of the dye-sensitized solar cell 20 except for the electrodes was produced. A specific configuration is shown in FIG. 41 is a transparent electrode, 42 is a semiconductor electrode, 43 is a transparent conductive film, 44 is a substrate, 45 is a semiconductor layer, 46 is a light scattering layer, 40 is a photoelectrode, 20 is a dye-sensitized solar cell, CE is a counter electrode, E Is an electrolyte, and S is a spacer.

A transparent electrode in which a fluorine-doped SnO ₂ conductive film (film thickness: 500 nm) was formed on a glass substrate was prepared. Then, the SnO ₂ conductive film, a paste 2 described above by screen printing and then dried. Then, it baked on the conditions of 450 degreeC in the air. Furthermore, by repeating this screen printing and baking using the paste 4, a semiconductor electrode having the same configuration as the semiconductor electrode 42 shown in FIG. 2 on the SnO ₂ conductive film (light receiving surface area; 10 mm × 10 mm, layer thickness) 10 μm, layer thickness of semiconductor layer; 6 μm, layer thickness of light scattering layer; 4 μm, content of rod-like TiO ₂ particles 1 contained in the light scattering layer; 30% by mass), containing sensitizing dye A photoelectrode was prepared.

Next, the pigment | dye was made to adsorb | suck to a semiconductor electrode as follows. First, with the use of anhydrous ethanol dehydrated with magnesium ethoxide as a solvent, the dyes listed in Table 1 below were dissolved so that the concentration was 3 × 10 ⁻⁴ mol / L to prepare a dye solution. Next, the semiconductor electrode was immersed in this solution, whereby the dye was adsorbed to the semiconductor electrode by about 1.5 × 10 ⁻⁷ mol / cm ² to complete the photoelectrode 10.

  Next, a platinum electrode (thickness of Pt thin film; 100 nm) having the same shape and size as the above-described photoelectrode as a counter electrode, and an iodine redox solution containing iodine and lithium iodide as an electrolyte E were prepared. Furthermore, a DuPont spacer S (trade name: “Surlin”) having a shape matched to the size of the semiconductor electrode was prepared, and as shown in FIG. 3 described in JP-A-2002-289274, a photoelectrode 40, counter electrode CE, and spacer S were opposed to each other, and the above electrolyte was filled therein to complete a dye-sensitized solar cell.

(Test method)
A battery characteristic test was performed, and the conversion efficiency η was measured for the dye-sensitized solar cell. The battery characteristic test was performed by irradiating 1000 W / m ² of pseudo-sunlight from a xenon lamp through an AM1.5 filter using a solar simulator (manufactured by WACOM, WXS-85H). Current-voltage characteristics were measured using an IV tester to determine conversion efficiency (η /%) and the like.
Moreover, the IPCE (quantum yield) in 400-900 nm was measured with the IPCE measuring apparatus made from Peccell. (IPCE at 850 nm is shown in Table 1 below.)
The following items were evaluated and judged. It is possible to obtain a high evaluation in the market if all are A or more.

(Initial conversion efficiency)
AA: 7.5% or more A: 7.0% or more and less than 7.5% B: 5.0% or more and less than 7.0% C: Less than 5.0%

(850 nm IPCE)
AA: 10% or more A: 8% or more and less than 10% B: 6% or more and less than 8% C: Less than 6%

(Drop rate of conversion efficiency after dark storage [γd])
The photoelectric conversion efficiency (η _f ) after aging at 80 ° C. for 300 hours was measured. Evaluation was performed by determining the rate of decrease (γd: the following formula) of η _f with _{respect to} the initial conversion efficiency (η _i ).
Formula: Rate of descent (γd) = (η _i −η _f ) / (η _i )
A: γd is less than 5% A: γd is 5% or more and less than 10% B: γd is 10% or more and less than 20% C: γd is 20% or more

(Decrease rate of conversion efficiency after irradiation [γL])
The photoelectric conversion efficiency (η _g ) of the conversion efficiency after continuous light irradiation for 500 hours was measured. Evaluation was performed by determining the rate of decrease (γL: the following equation) of the initial conversion efficiency (η _i ) of η _g .
Formula: Descent rate (γL) = (η _i −η _g ) / (η _i )
AA: γL is less than 5% A: γL is 5% or more and less than 10% B: γL is 10% or more and less than 15% C: γL is 15% or more

The results are shown in Table 1 below.

比較用色素Ａは国際特許公開９８／５０３９３号パンフレットに記載のルテニウム錯体色素である。 Comparative dye

The comparative dye A is a ruthenium complex dye described in International Patent Publication No. 98/50393 pamphlet.

As can be seen from the above results, according to the dye of the present invention, it can be seen that the IPCE and conversion efficiency in the long wavelength region, other current / voltage characteristics, and further excellent results superior to conventional dyes are exhibited. . Especially, what has a specific substituent in 4-position in the pyridine ring of a multicyclic ligand (Formula L2) (test Dye1, 4) had a remarkable effect.
Further, the combination effect with the combination dye (2) was also deteriorated with the conventional dyes A and B (the initial conversion efficiency and durability were the same in the order of determination, but deteriorated). A tendency was seen), and a good combination effect was confirmed for the dye of the present invention (see Test 201-203).

  In addition, it tested similarly about the pastes 1-14 other than the said paste 2, and confirmed that favorable performance was obtained according to the pigment | dye of this invention. In particular, the pastes 10 and 13 showed high performance in photoelectric conversion efficiency and durability.

(Example 2)
A dye-sensitized solar cell having the same configuration as that shown in FIG. 1 described in JP 2010-218770 A was prepared by the following procedure. A specific configuration is shown in FIG. 51 is a transparent substrate, 52 is a transparent conductive film, 53 is a barrier layer, 54 is an n-type semiconductor electrode, 55 is a p-type semiconductor layer, 56 is a p-type semiconductor film, and 57 is a counter electrode (57a is a protrusion of the counter electrode). .

A transparent conductive (XCO) glass substrate in which SnO ₂ : F (fluorine-doped tin oxide) as a transparent conductive film 52 is formed on a transparent glass plate as a transparent substrate 51 of 20 mm × 20 mm × 1 mm by CVD is prepared. did.
Next, 5 ml of a solution in which Ti (OCH (CH ₃ ) ₂ ) ₄ and water are mixed at a volume ratio of 4: 1 is mixed with 40 ml of an ethyl alcohol solution adjusted to pH 1 with hydrochloride, and the TiO ₂ precursor is mixed. A solution was prepared. This solution was spin-coated on a TCO glass substrate at 1000 rpm and sol-gel synthesis was performed, followed by heating under vacuum at 78 ° C. for 45 minutes, annealing at 450 ° C. for 30 minutes, and a titanium oxide thin film A barrier layer (53) consisting of was formed.

On the other hand, anatase-type titanium oxide particles having an average particle size of 18 nm (particle size: 10 nm to 30 nm) are uniformly dispersed in a mixed solvent of ethanol and methanol (ethanol: methanol = 10: 1 (volume ratio)) to form titanium oxide. A slurry was prepared. At this time, the titanium oxide particles were uniformly dispersed using a homogenizer at a ratio of 10% by mass with respect to 100% by mass of the mixed solvent.
Next, a solution in which ethyl cellulose as a viscosity modifier is dissolved in ethanol so as to have a concentration of 10% by mass and an alcohol-based organic solvent (terpineol) are added to the titanium oxide slurry prepared above, and again And homogeneously dispersed with a homogenizer. Thereafter, alcohol other than terpineol was removed with an evaporator and mixed with a mixer to prepare a paste-like titanium oxide particle-containing composition. In addition, the composition of the prepared titanium oxide particle containing composition made the titanium oxide particle containing composition 100 mass%, the titanium oxide particle was 20 mass%, and the viscosity modifier was 5 mass%.

The titanium oxide particle-containing composition thus prepared was applied on the barrier layer 53 formed above so as to form a predetermined pattern by screen printing, dried at 150 ° C., and then in an electric furnace. By heating to 450 ° C., a laminate in which the n-type semiconductor electrode 54 was laminated on the TCO glass substrate was obtained. Next, this laminate was immersed in a zinc nitrate (ZnNO ₃ ) solution overnight, and then heated at 450 ° C. for 45 minutes for surface treatment. Then, the surface-treated laminate was immersed in the ethanol solution (concentration of sensitizing dye: 3 × 10 ⁻⁴ mol / L) using various dyes shown in Table 1, and left at 25 ° C. for 40 hours. Thus, the dye was adsorbed inside the n-type semiconductor electrode 54.

  Subsequently, CuI was added to acetonitrile to prepare a saturated solution, and 6 mg of the supernatant was taken out, and 15 mg of 1-methyl-3-ethylimidazolium thiocyanate was added to prepare a p-type semiconductor solution. . Then, on the hot plate heated to 80 ° C., the stacked body after the dye is added to the n-type semiconductor electrode 54 is placed, and a solution of the p-type semiconductor is dropped onto the n-type semiconductor electrode 54 with a pipette. Then, the p-type semiconductor layer 55 was produced by allowing it to stand for 1 minute and drying.

  Next, a copper plate having a thickness of 1 mm was washed with 1 M hydrochloric acid, and further washed with absolute ethanol, and then heated in the atmosphere at 500 ° C. for 4 hours to obtain a CuO nanowire having a maximum diameter of 100 nm and a height of 10 μm (protrusion 57a ) Was grown. This copper plate was sealed with iodine crystals in a sealed container and heated in a thermostatic bath at 60 ° C. for 1 hour to produce a counter electrode 57 having a thin CuI layer (p-type semiconductor film 56) coated on the surface. Then, the counter electrode 57 was pressed against the laminated body produced above from the p-type semiconductor layer 55 side and laminated.

  The dye-sensitized solar cell thus produced was tested for initial conversion efficiency in the same manner as in Example 1. As a result, it was confirmed that good performance and improvement effect can be obtained according to the dye of the present invention.

(Example 3)
By the following method, the CdSe quantum dot-ized process was performed to the photoelectrode, and the dye-sensitized solar cell shown in FIG. 4 was created using the electrolyte solution using a cobalt complex.

FTO glass (1), manufactured by Nippon Sheet Glass Co., Ltd. Surface resistance: 8Ω sq ⁻¹ ) The titanium (IV) bis (acetylacetonato) diisopropoxide ethanol solution was sprayed 16 times on the surface, and the temperature was 450 ° C. for 30 minutes. It baked above. A transparent layer of about 2.1 μm with 20 nm-TiO ₂ and a light scattering layer of about 6.2 μm with 60 nm-TiO ₂ (manufactured by Showa Titanium Co., Ltd.) were laminated on this substrate by screen printing, and later with an aqueous TiCl ₄ solution. Processing was performed to prepare FTO / TiO ₂ film 2.

The FTO / TiO ₂ film was immersed in a 0.03M Cd (NO ₃ ) ₂ ethanol solution for 30 seconds in a glove bag under an inert gas atmosphere, and then continuously immersed in a 0.03M selenide ethanol solution for 30 seconds. Soaked. Then, it wash | cleaned in ethanol for 1 minute or more, the excess precursor was removed, and it dried. This dipping → cleaning → drying process was repeated five times to grow CdSe quantum dots (23) on the titanium oxide layer (22), and a surface stabilization treatment was performed with CdTe to produce a CdSe-treated photoelectrode.
Selenide (Se ²⁻ ) was adjusted in the system by adding 0.068 g of NaBH ₄ (to a concentration of 0.060M) to a 0.030M SeO ₂ ethanol solution under Ar or N ₂ atmosphere.

After the CdSe-treated photoelectrode is immersed in the dye solution for 4 hours to adsorb the dye 21 to the photoelectrode, this photoelectrode and the counter electrode (4, hexachloroplatinic acid 2-propanol solution (0.05 M) on FTO glass at 400 ° C.) 20 minutes of Pt chemically deposited) was assembled with a 25 μm thick Surlyn (made by DuPont Co., Ltd.) ring sandwiched, and sealed by heat dissolution. Electrolyte using cobalt complex (0.75 M Co (o-phen) ₃ ²⁺ , 0.075 M Co (o-phen) ₃ ³⁺ , 0.20 M LiClO ₄ acetonitrile / ethylene carbonate (4: 6 / v: v ) Solution) is injected into the gap 3 between the electrodes through a hole previously formed on the side of the counter electrode, and then the hole is closed by heat with a Binell (DuPont) sheet and a thin glass slide. Battery cell 10 was produced.
The cobalt complex added to the electrolytic solution was prepared by the method described in Chemical Communications, Vol. 46, pages 8788-8790 (2010).

  The dye-sensitized solar cell thus produced was tested for initial conversion efficiency in the same manner as in Example 1. As a result, it was confirmed that good performance and improvement effect can be obtained according to the dye of the present invention.

Japanese Patent Application Laid-Open No. 2004-146425, solar cell using the cell shown in FIG. 2, Japanese Patent Application Laid-Open No. 2004-152613, solar cell using the photoelectrode shown in FIG. 1, Japanese Patent Application Laid-Open No. 2000-90989 A solar cell using a tandem cell prepared in the same manner as in Example 1 and a dye-sensitized solar cell shown in FIG. 1 of JP-A No. 2003-217688 were prepared and subjected to the same test as described above. As a result, it was confirmed that good performance can be obtained with any of the dyes of the present invention.
In addition, the experiment in paragraphs [0053] to [0076] of Japanese Patent Laid-Open No. 2002-367686, the experiment in paragraphs [0043] to [0055] of Japanese Patent Laid-Open No. 2003-323818, and the paragraph [0073] of Japanese Patent Laid-Open No. 2001-43907 are disclosed. To [0090], paragraphs [0014] to [0022] in JP 2000-340269, paragraphs [0022] to [0066] in JP 2005-85500, and JP 2004-273272. Experiments in paragraphs [0014] to [0016], experiments in paragraphs [0155] to [0167] of JP 2000-323190 A, experiments in paragraphs [0137] to [0147] in JP 2000-228234 A, JP 2001 -266963, paragraphs [0085] to [0092] experiment, Japanese Patent Laid-Open No. 2001-185244 Experiments in paragraphs [0036] to [0045], experiment in Example 6 on pages 59 to 60 in JP 2001-525108 A, experiments in paragraphs [0023] to [0026] in JP 2001-203377 A, JP Experiments in paragraphs [0046] to [0054] in Japanese Patent Laid-Open No. 2000-1000048, experiments in paragraphs [0043] to [0055] in Japanese Patent Laid-Open No. 2001-210390, and paragraphs [0080] to [0086] in Japanese Patent Laid-Open No. 2002-280588. Experiment, Experiment of Paragraphs [0089] to [0104] of Japanese Patent Laid-Open No. 2001-273937, Experiment of Paragraphs [0160] to [0171] of Japanese Patent Laid-Open No. 2000-285777, Paragraph [0105] of Japanese Patent Laid-Open No. 2001-320068 Good results were confirmed in the combination of the experiment of [0116] and the compound of the present invention.

DESCRIPTION OF SYMBOLS 1 Conductive support body 2 Photoconductor layer 21 Dye 22 Semiconductor fine particle 23 CdSe quantum dot 3 Charge transfer body layer 4 Counter electrode 5 Photoreceptive electrode 6 Circuit 10 Photoelectric conversion element 100 Photoelectrochemical cell M Electric motor (electric fan)

41 transparent electrode 42 semiconductor electrode 43 transparent conductive film 44 substrate 45 semiconductor layer 46 light scattering layer 40 photoelectrode 20 dye-sensitized solar cell CE counter electrode E electrolyte S spacer 51 transparent substrate 52 transparent conductive film 53 barrier layer 54 n-type semiconductor electrode 55 p-type semiconductor layer 56 p-type semiconductor film 57 counter electrode 57a protrusion

Claims (7)

A photoelectric conversion element having a laminated structure in which a photosensitive body having a layer of semiconductor fine particles adsorbed with a dye, a charge transfer body, and a counter electrode are disposed on a conductive support, wherein the dye is represented by the following formula ( A photoelectric conversion element using the metal complex dye represented by 1).
ML ¹ L ² X (1)
[Wherein M represents a transition metal selected from ruthenium, osmium, iron, rhenium, and technetium. X represents NCS ⁻ , Cl ⁻ , Br ⁻ , I ⁻ , CN ⁻ , NCO ⁻ , H ₂ O, or NCN ₂ ⁻ . L ¹ represents a tridentate ligand represented by the following formula (L1), and L ² represents a bidentate ligand represented by any of the following formulas (L2-1) to (L2-5). Represents. ]

[In the formula (L1), Za, Zb and Zc each independently represent a nonmetallic atom group capable of forming a 5- or 6-membered ring. However, at least one of the rings formed by Za, Zb and Zc has an acidic group. ]

[Wherein, G ¹ represents a structure represented by any of the following formulas (G1-1) to (G1-6), and G ² represents any of the following formulas (G2-1) to (G2-3): The structure represented by R represents a substituent. n1 represents an integer of 0 to 3. n2 represents an integer of 0 to 5. ]

[Wherein R ^{1 to} R ⁴ represent a hydrogen atom, an alkyl group, a heteroaryl group, an aryl group, COOH, PO (OH) ² , PO (OR) (OH), or CO (NHOH). Here, R represents an alkyl group, a heteroaryl group, or an aryl group. * Represents a bond. ] The photoelectric conversion element according to claim 1, wherein L ² is represented by formula (L2-1) or (L2-2). The photoelectric conversion element according to claim 1 or 2, wherein the G ¹ is represented by (G1-1), (G1-2), or (G1-5). The photoelectric conversion element according to claim 1, wherein G ² is represented by (G2-1) or (G2-2). The photoelectric conversion element of any one of Claims 1-4 in which the said photoreceptor further contains the pigment | dye represented by following formula (2).
MzL ³ _m3 L ⁴ _m4 Y _mY · CI (2)
[In Formula (2), Mz represents a metal atom. L ³ represents a ligand represented by the following formula (L3). L ⁴ represents a ligand represented by the following formula (L4). Y represents a monodentate or bidentate ligand. m3 represents an integer of 0 to 3. m4 represents an integer of 1 to 3. mY represents an integer of 0-2. CI represents a counter ion when a counter ion is required to neutralize the charge. ]

(In formula (L3), Ac represents an acidic group, R ^a represents ^a substituent, R ^b represents an alkyl group or an aromatic ring group, e1 and e2 represent an integer of 0 to 5. L ^c and L ^d represents a conjugated chain, e3 represents 0 or 1, f represents an integer of 0 to 3, and g represents an integer of 0 to 3.)

(In the formula (L4), Zd, Ze and Zf represent an atomic group capable of forming a 5- or 6-membered ring. H represents 0 or 1. However, at least one of the rings formed by Zd, Ze and Zf. One has an acidic group.)   The photoelectrochemical cell using the photoelectric conversion element of any one of Claims 1-5. The pigment | dye represented by following General formula (1).
ML ¹ L ² X (1)
[Wherein M represents a transition metal selected from ruthenium, osmium, iron, rhenium, and technetium. X represents NCS ⁻ , Cl ⁻ , Br ⁻ , I ⁻ , CN ⁻ , NCO ⁻ , H ₂ O, or NCN ₂ ⁻ . L ¹ represents a tridentate ligand represented by the following formula (L1), and L ² represents a bidentate ligand represented by any of the following formulas (L2-1) to (L2-5). Represents.

In the formula (L1), Za, Zb and Zc each independently represent a nonmetallic atom group capable of forming a 5- or 6-membered ring. However, at least one of the rings formed by Za, Zb and Zc has an acidic group.

In formulas (L2-1) to (L2-5), G ¹ represents a structure represented by any of the following formulas (G1-1) to (G1-6), and G ² represents the following formula (G2- 1) A structure represented by any one of (G2-3) is shown.

In the formula, R ^{1 to} R ³ represent a hydrogen atom, an alkyl group, a heteroaryl group, an aryl group, COOH, PO (OH) ₂ , PO (OR) (OH), or CO (NHOH). Here, R represents an alkyl group, a heteroaryl group, or an aryl group. * Represents a bond. ]

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