JP5620314B2 - Photoelectric conversion element, photoelectrochemical cell, dye for photoelectric conversion element and dye solution for photoelectric conversion element - Google Patents

Description

  The present invention relates to a photoelectric conversion element and a photoelectrochemical cell having high conversion efficiency and excellent durability. The present invention also relates to a photoelectric conversion element dye and a photoelectric conversion element dye solution.

  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 greatly as it uses 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, Graetzel et al. Of Lausanne University of Technology in Switzerland developed a dye-sensitized solar cell in which a dye composed of a ruthenium complex was fixed on the surface of a porous titanium oxide thin film, and realized conversion efficiency comparable to 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. However, although conventional ruthenium complex dyes can be photoelectrically converted using visible light, they can hardly absorb infrared light having a wavelength longer than 700 nm, and thus have a low photoelectric conversion ability in the infrared region.
Then, the proposal which provides a photoelectric conversion element with high conversion efficiency in the infrared region higher than 700 nm by using the polymethine dye which has a specific structure is proposed (for example, refer patent document 2).
By the way, the photoelectric conversion element is required to have high initial conversion efficiency in a wide wavelength region, little deterioration in conversion efficiency after use, and excellent durability. However, in terms of durability, the photoelectric conversion element described in Patent Document 2 is not sufficient.
Therefore, a photoelectric conversion element and a photoelectrochemical cell having high conversion efficiency and excellent durability are required. Furthermore, the pigment | dye for photoelectric conversion elements and the pigment | dye solution for photoelectric conversion elements are required.

US Pat. No. 5,463,057 Japanese Patent No. 4217320

  An object of the present invention is to provide a photoelectric conversion element and a photoelectrochemical cell having high conversion efficiency and excellent durability. Moreover, the subject of this invention is providing the pigment | dye solution for photoelectric conversion elements, and the pigment | dye solution for photoelectric conversion elements.

As a result of intensive studies, the present inventors have made a photoconductor, a charge transfer body, and a counter electrode having a porous semiconductor fine particle layer in which a polymethine dye (dye compound) having a specific structure is adsorbed on a conductive support. It has been found that a photoelectric conversion element having a laminated structure including a photoelectrochemical cell using the photoelectric conversion element has high conversion efficiency in a wide wavelength range and excellent durability. The present invention has been made based on this finding.
The object of the present invention has been achieved by the following means.

［一般式（１）において、Ｑは、フッ素原子または塩素原子を有してもよい、４価のベンゼン環基を表し、Ｘ^１ およびＸ^２はそれぞれ独立に硫黄原子、酸素原子またはＣＲ^１Ｒ^２を表す。ここでＲ^１、Ｒ^２はそれぞれ独立にアルキル基を表す。ＲおよびＲ’はそれぞれ独立にアルキル基を表す。Ｐ^１、Ｐ^２はそれぞれ独立に、下記一般式（２）または（３）で表される基を表す。Ｗ^１は電荷を中和させるのに必要な場合の対イオンを表す。］

［一般式（２）および（３）において、Ｖ ^１ はカルボキシ基、フッ素原子、アルキル基、アルケニル基、アルキニル基、芳香族基、炭素原子で結合するヘテロ環基または２つのＶ ^１ が互いに結合してベンゼン環を形成する基を表す。ｎは０〜２の整数を表す。ｎが２の場合は、Ｖ ^１ は同じでも異なっていてもよい。
ＹはＳ、ＮＲ ^９ 、またはＣＲ ^１０ Ｒ ^１１ を表す。Ｒ ^９ はアルキル基を表す。Ｒ ^１０ およびＲ ^１１ は、アルキル基を表し、同一でも異なっていてもよい。
Ｚは、カルボキシ基、４−カルボキシフェニル基または３，４−ジカルボキシフェニル基が置換してもよいアルキル基を表す。
Ｒ ^３ 〜Ｒ ^６ およびＲ ^８ はそれぞれ独立に、水素原子またはアルキル基を表す。
Ｒ ^７ は酸素原子、または、下記一般式（１０）〜（１３）のいずれかで表される基を表す。］

［一般式（１０）〜（１３）において、Ｒｆは水素原子またはアルキル基を表す。］

ただし、前記炭素数５〜１８のアルキル基を、Ｘ ^１ およびＸ ^２ に該アルキル基を有する場合、Ｘ ^１ およびＸ ^２ がＣＲ ^１ Ｒ ^２ であって、Ｒ ^１ およびＲ ^２ が、炭素数５〜１８のアルキル基であり、Ｐ ^１ およびＰ ^２ 部分に前記炭素数５〜１８のアルキル基を有する場合、ＹがＣＲ ^１０ Ｒ ^１１ であって、Ｒ ^１０ およびＲ ^１１ が、炭素数５〜１８のアルキル基であるか、または、Ｚが、炭素数５〜１８のアルキル基である。
＜２＞前記炭素数５〜１８のアルキル基が分岐アルキル基であることを特徴とする＜１＞に記載の光電変換素子。
＜３＞前記一般式（１）におけるＰ^１ およびＰ^２が、それぞれ独立に下記一般式（４）または（５）で表されることを特徴とする＜１＞または＜２＞に記載の光電変換素子。

［一般式（４）および（５）において、Ｖ^１はカルボキシ基、フッ素原子、アルキル基、アルケニル基、アルキニル基、芳香族基、炭素原子で結合するヘテロ環基または２つのＶ ^１ が互いに結合してベンゼン環を形成する基を表す。ｎは０〜２の整数を表す。ｎが２の場合は、Ｖ^１は同じでも異なっていてもよい。
ＹはＳ、ＮＲ^９、またはＣＲ^１０Ｒ^１１を表す。Ｒ^９はアルキル基を表す。Ｒ^１０ およびＲ^１１は、アルキル基を表し、同一でも異なっていてもよい。
Ｚは、カルボキシ基、４−カルボキシフェニル基または３，４−ジカルボキシフェニル基が置換してもよいアルキル基を表す。］
＜４＞前記Ｖ^１が、カルボキシ基、または、カルボキシ基が置換した、アルキル基、アルケニル基、アルキニル基、芳香族基もしくは炭素原子で結合するヘテロ環基であることを特徴とする＜１＞〜＜３＞のいずれか１項に記載の光電変換素子。
＜５＞前記Ｖ^１が、５−カルボキシ基、５−メチル基または、２つのＶ ^１ が互いに結合して形成される４，５−ベンゼン環縮合であることを特徴とする＜１＞〜＜３＞のいずれか１項に記載の光電変換素子。
＜６＞前記ＺおよびＶ^１ が、カルボキシ基、または、カルボキシ基が置換した、アルキル基、アルケニル基、アルキニル基、芳香族基もしくは炭素原子で結合するヘテロ環基であることを特徴とする＜１＞〜＜５＞のいずれか１項に記載の光電変換素子。
＜７＞前記一般式（２）が下記一般式（６）で表され、前記一般式（３）が下記一般式（７）で表されることを特徴とする＜１＞〜＜６＞のいずれか１項に記載の光電変換素子。

［一般式（６）および（７）において、Ｙ、Ｚ、Ｒ^３〜Ｒ^８は、前記一般式（２）または（３）のＹ、Ｚ、Ｒ^３〜Ｒ^８と同義である。Ｖ^１２はカルボキシ基を表す。Ｅ ^１１ 〜Ｅ ^１３ は、水素原子、カルボキシ基、フッ素原子、アルキル基、アルケニル基、アルキニル基、芳香族基または炭素原子で結合するヘテロ環基を表す。ただし、Ｅ^１１〜Ｅ^１３のうち少なくとも１つは電子吸引基であり、残りの２つは水素原子である。ｐは２を表す。］
＜８＞前記一般式（２）が下記一般式（８）で表され、前記一般式（３）が下記一般式（９）で表されることを特徴とする＜１＞〜＜３＞のいずれか１項に記載の光電変換素子。

［一般式（８）および（９）において、Ｙ、Ｚ、Ｒ^３〜Ｒ^８は、前記一般式（２）または（３）のＹ、Ｚ、Ｒ^３〜Ｒ^８と同義である。Ｌは上記式Ａ〜Ｄで表され、ｍは０〜３の整数を表す。ｍが２以上のとき、それぞれ異なっていてもよい。式Ａにおいて、Ｘａは、ＮＲｅ、ＯまたはＳを表す。ここで、Ｒｅは水素原子またはアルキル基を表す。式Ａおよび式Ｃにおいて、Ｒ_ａ〜Ｒ_ｄは水素原子、アルキル基、カルボキシ基を表す。一般式（８）において、ｐは２を表す。Ｒｘはカルボキシ基または−ＣＨ＝Ｃ（ＣＮ）（ＣＯＯＨ）を表す。］
＜９＞前記Ｙが、Ｓ、ＮＣＨ_３ またはＣ（ＣＨ_３）_２を表し、Ｚが炭素数５〜１８のアルキル基を表すことを特徴とする＜１＞〜＜８＞のいずれか１項に記載の光電変換素子。
＜１０＞前記Ｒ^７が、前記一般式（１０）〜（１３）のいずれかで表されることを特徴とする＜１＞、＜２＞、＜４＞〜＜９＞のいずれか１項に記載の光電変換素子。
＜１１＞前記Ｒ^７が、下記一般式（１０）または（１１）で表されることを特徴とする＜１＞、＜２＞、＜４＞〜＜１０＞のいずれか１項に記載の光電変換素子。

＜１２＞一般式（１）中のＸ^１、Ｘ^２はそれぞれ独立に硫黄原子、酸素原子またはＣ（ＣＨ_３）_２を表し、ＲおよびＲ’はそれぞれ独立に炭素数５〜１８のアルキル基を表すことを特徴とする＜１＞〜＜１１＞のいずれか１項に記載の光電変換素子。
＜１３＞前記半導体微粒子が酸化チタン微粒子であることを特徴とする＜１＞〜＜１２＞のいずれか１項に記載の光電変換素子。
＜１４＞前記＜１＞〜＜１３＞のいずれか１項に記載の光電変換素子を備えることを特徴とする光電気化学電池。
＜１５＞下記一般式（１）で表され、分子中の下記Ｘ ^１ およびＸ ^２ 、または、下記Ｐ ^１ およびＰ ^２ 部分に、炭素数５〜１８のアルキル基を有する光電変換素子用色素。

［一般式（１）において、Ｑは、フッ素原子または塩素原子を有してもよい、４価のベンゼン環基を表し、Ｘ^１ およびＸ^２はそれぞれ独立に硫黄原子、酸素原子またはＣＲ^１Ｒ^２を表す。ここでＲ^１、Ｒ^２はそれぞれ独立にアルキル基を表す。ＲおよびＲ’はそれぞれ独立にアルキル基を表す。Ｐ^１、Ｐ^２はそれぞれ独立に、下記一般式（２）または（３）で表される基を表す。Ｗ^１は電荷を中和させるのに必要な場合の対イオンを表す。］

［一般式（２）および（３）において、Ｖ ^１ はカルボキシ基、フッ素原子、アルキル基、アルケニル基、アルキニル基、芳香族基、炭素原子で結合するヘテロ環基または２つのＶ ^１ が互いに結合してベンゼン環を形成する基を表す。ｎは０〜２の整数を表す。ｎが２の場合は、Ｖ ^１ は同じでも異なっていてもよい。
ＹはＳ、ＮＲ ^９ 、またはＣＲ ^１０ Ｒ ^１１ を表す。Ｒ ^９ はアルキル基を表す。Ｒ ^１０ およびＲ ^１１ は、アルキル基を表し、同一でも異なっていてもよい。
Ｚは、カルボキシ基、４−カルボキシフェニル基または３，４−ジカルボキシフェニル基が置換してもよいアルキル基を表す。
Ｒ ^３ 〜Ｒ ^６ およびＲ ^８ はそれぞれ独立に、水素原子またはアルキル基を表す。
Ｒ ^７ は酸素原子、または、下記一般式（１０）〜（１３）のいずれかで表される基を表す。］

［一般式（１０）〜（１３）において、Ｒｆは水素原子またはアルキル基を表す。］

ただし、前記炭素数５〜１８のアルキル基を、Ｘ ^１ およびＸ ^２ に該アルキル基を有する場合、Ｘ ^１ およびＸ ^２ がＣＲ ^１ Ｒ ^２ であって、Ｒ ^１ およびＲ ^２ が、炭素数５〜１８のアルキル基であり、Ｐ ^１ およびＰ ^２ 部分に前記炭素数５〜１８のアルキル基を有する場合、ＹがＣＲ ^１０ Ｒ ^１１ であって、Ｒ ^１０ およびＲ ^１１ が、炭素数５〜１８のアルキル基であるか、または、Ｚが、炭素数５〜１８のアルキル基である。
＜１６＞有機溶媒中に、＜１５＞に記載の光電変換素子用色素を含有し溶解したことを特徴とする光電変換素子用色素溶液。
<1> and dye represented by the following general formula (1), a photoelectric conversion element having a photoconductive layer and a semiconductor particle, the pigment, the following X ¹ and X ² in the ^molecule, or, below ^{P 1} and ^{P 2} parts, a photoelectric conversion element characterized and Turkey that having an alkyl group having 5 to 18 carbon atoms.

[In the general formula (1), Q may have a fluorine atom or a chlorine atom, and display the tetravalent benzene ring, X ¹ and X ² each independently represent a sulfur atom, SansoHara child or CR ¹ R ² is represented. Wherein ^R 1, ^{R 2} is to display the alkyl group independently. R and R 'to display the alkyl group independently. P ¹ and P ² each independently represent a group represented by the following general formula (2) or (3) . W ¹ represents a counter ion as necessary to neutralize the charge. ]

[In General Formulas (2) and (3), V ¹ is a carboxy group, a fluorine atom, an alkyl group, an alkenyl group, an alkynyl group, an aromatic group, a heterocyclic group bonded by a carbon atom, or two V ¹ are bonded to each other. Represents a group that forms a benzene ring. n represents an integer of 0 to 2. When n is 2, V ¹ may be the same or different.
Y represents S, NR ⁹ , or CR ¹⁰ R ¹¹ . R ⁹ represents an alkyl group. R ¹⁰ and R ¹¹ represent an alkyl group and may be the same or different.
Z represents an alkyl group which may be substituted by a carboxy group, a 4-carboxyphenyl group or a 3,4-dicarboxyphenyl group.
R ^{3 to} R ⁶ and R ⁸ each independently represents a hydrogen atom or an alkyl group.
R ⁷ represents an oxygen atom or a group represented by any one of the following general formulas (10) to (13). ]

[In General Formulas (10) to (13), Rf represents a hydrogen atom or an alkyl group. ]

However, when the alkyl group having 5 to 18 carbon atoms has the alkyl group in X ¹ and X ² , X ¹ and X ² are CR ¹ R ² , and R ¹ and R ² are 5 carbon atoms. In the case where the P ¹ and P ² moieties have the alkyl group having 5 to 18 carbon atoms, Y is CR ¹⁰ R ¹¹ , and R ¹⁰ and R ¹¹ are 5 to 18 carbon atoms. Or Z is an alkyl group having 5 to 18 carbon atoms.
<2>, wherein the alkyl group of the 5 to 18 carbon atoms is a branched alkyl group photoelectric conversion element according to <1>.
<3> ^{P 1} and ^{P 2} in the general formula (1) are each independently the following general formula (4) or is characterized by being represented by (5) to <1> or <2> The photoelectric conversion element as described.

[In the general formula (4) and (5), V ¹ is a carboxy group, a fluorine atom, an alkyl group, an alkenyl group, an alkynyl group, an aromatic group, a heterocyclic group, or two V ¹ having a carbon atom bonded to A group that is bonded to each other to form a benzene ring is represented. n is to table an integer of 0-2. If n is 2, V ¹ may be the same or different.
Y represents S, NR ⁹ , or CR ¹⁰ R ¹¹ . R ⁹ represents an alkyl group . R ¹⁰ and R ¹¹ represent an alkyl group and may be the same or different.
Z represents an alkyl group which may be substituted by a carboxy group, a 4-carboxyphenyl group or a 3,4-dicarboxyphenyl group. ]
< 4 > The V ¹ is a carboxy group or an alkyl group, an alkenyl group, an alkynyl group, an aromatic group, or a heterocyclic group bonded by a carbon atom, which is substituted by a carboxy group. < 1> The photoelectric conversion element according to any one of to <3> .
<5> wherein ^{V 1} is, 5 - carboxy sheet group, 5 - or a methyl group, wherein the two ^{V 1} is a bond to be formed with 4,5-benzene ring fused to one another <1> The photoelectric conversion element according to any one of to < 3 >.
<6> the Z and V ¹ is, it said the carboxy group or a carboxy group is substituted, an alkyl group, an alkenyl group, an alkynyl group, a heterocyclic group bonded to an aromatic group or a carbon atom The photoelectric conversion element according to any one of < 1> to <5> .
< 7 > The general formula (2) is represented by the following general formula (6), and the general formula (3) is represented by the following general formula (7). < 1 > to < 6 > the photoelectric conversion element of any one.

[In one general formula (6) and ^{(7), Y, Z,} R 3 ~R 8 , the or general formula (2) (3) Y, ^Z, synonymous with R 3 to R ⁸ is there. V ¹² is to display the carboxy group. E ^{11 to} E ^{13 each} represents a hydrogen atom, a carboxy group, a fluorine atom, an alkyl group, an alkenyl group, an alkynyl group, an aromatic group, or a heterocyclic group bonded with a carbon atom. However, at least one of E ^{11 to} E ¹³ is an electron withdrawing group , and the remaining two are hydrogen atoms . p represents 2. ]
< 8 > The general formula (2) is represented by the following general formula (8), and the general formula (3) is represented by the following general formula (9). <1> to < 3 > the photoelectric conversion element of any one.

[In the general formula (8) and (9), Y, ^Z, R 3 to R ^8, the or general formula (2) has the same definition Y, ^Z, and R 3 to R ⁸ (3) . L is represented by the above following formula to D, m represents 0-3 integer. When m is 2 or more, they may be different from each other. In Formula A, Xa represents NRe, O, or S. Here, Re is or a hydrogen atom an alkyl group. In formula A and formula _C, R a to R _d represents a hydrogen atom, an alkyl group, a carboxy group. In the general formula (8), p represents 2 . Rx represents a carboxy group or —CH═C (CN) (COOH) . ]
<9> wherein Y is, S, NCH ₃ or represents a C _{(CH 3) 2,} Z is characterized in that an alkyl group having 5 to 18 carbon atoms <1> - or <8> 1 the photoelectric conversion device according to claim.
<10> wherein ^{R 7} is characterized by being represented by any one of the previous following general formula (10) to (13) <1>, <2>, any of <4> to <9> the photoelectric conversion element according to claim.
<11> wherein ^{R 7} is, or the following general formula (10), characterized by being represented by (11) <1>, <2>, according to any one of <4> to <10> Photoelectric conversion element.

<12> the general formula (1) ^X 1, ^{X 2} each independently represent a sulfur atom, or oxygen atom represents C _{(CH 3) 2,} R and R 'independently of 5 to 18 carbon atoms alkylene The photoelectric conversion element according to any one of <1> to < 11 >, wherein the photoelectric conversion element represents a ruthenium group.
< 13 > The photoelectric conversion element according to any one of <1> to < 12 >, wherein the semiconductor fine particles are titanium oxide fine particles.
<14> the <1> to photoelectrochemical cell characterized by comprising a photoelectric conversion element according to any one of <13>.
< 15 > A dye for a photoelectric conversion element which is represented by the following general formula (1) and has an alkyl group having 5 to 18 carbon atoms in the following X ¹ and X ² or the following P ¹ and P ² moieties in the molecule.

[In the general formula (1), Q may have a fluorine atom or a chlorine atom, and display the tetravalent benzene ring group, X ¹ and X ² are each independently a sulfur atom, an oxygen atom or CR ¹ R ² is represented. Wherein ^R 1, ^{R 2} is to display the alkyl group independently. R and R 'to display the alkyl group independently. P ¹ and P ² each independently represent a group represented by the following general formula (2) or (3) . W ¹ represents a counter ion as necessary to neutralize the charge. ]

[In General Formulas (2) and (3), V ¹ is a carboxy group, a fluorine atom, an alkyl group, an alkenyl group, an alkynyl group, an aromatic group, a heterocyclic group bonded by a carbon atom, or two V ¹ are bonded to each other. Represents a group that forms a benzene ring. n represents an integer of 0 to 2. When n is 2, V ¹ may be the same or different.
Y represents S, NR ⁹ , or CR ¹⁰ R ¹¹ . R ⁹ represents an alkyl group. R ¹⁰ and R ¹¹ represent an alkyl group and may be the same or different.
Z represents an alkyl group which may be substituted by a carboxy group, a 4-carboxyphenyl group or a 3,4-dicarboxyphenyl group.
R ^{3 to} R ⁶ and R ⁸ each independently represents a hydrogen atom or an alkyl group.
R ⁷ represents an oxygen atom or a group represented by any one of the following general formulas (10) to (13). ]

[In General Formulas (10) to (13), Rf represents a hydrogen atom or an alkyl group. ]

However, when the alkyl group having 5 to 18 carbon atoms has the alkyl group in X ¹ and X ² , X ¹ and X ² are CR ¹ R ² , and R ¹ and R ² are 5 carbon atoms. In the case where the P ¹ and P ² moieties have the alkyl group having 5 to 18 carbon atoms, Y is CR ¹⁰ R ¹¹ , and R ¹⁰ and R ¹¹ are 5 to 18 carbon atoms. Or Z is an alkyl group having 5 to 18 carbon atoms.
<16> in an organic solvent, a dye solution for a photoelectric conversion element characterized in that dissolving containing dye for a photoelectric conversion device according to <15>.

  According to the present invention, it is possible to provide a photoelectric conversion element and a photoelectrochemical cell having high conversion efficiency and excellent durability. Moreover, this invention can provide the pigment | dye solution for photoelectric conversion elements, and the pigment | dye solution for photoelectric conversion elements.

It is sectional drawing shown typically about one embodiment of the photoelectric conversion element of this invention.

  As a result of intensive studies, the present inventors have found that a photoelectric conversion element comprising a photoreceptor layer having a specific dye and semiconductor fine particles and a photoelectrochemical cell using the photoelectric conversion element have high photoelectric conversion efficiency and durability. It has been found that there is little decrease in performance, particularly photoelectric conversion efficiency. The present invention has been made based on this finding.

  A preferred embodiment of the photoelectric conversion element 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 semiconductor fine particles 22 and a sensitizing dye 21, and the dye 21 is adsorbed on the semiconductor fine particles 22 at least in part (the dye is in an adsorption equilibrium state and partially charged). May be present in the mobile 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. The electrons on the electrode return to the oxidized dye while working in an external circuit, thereby acting as a photoelectrochemical cell. At this time, the light receiving electrode 5 functions as a negative electrode of the battery.

  The photoelectric conversion element of the present invention has a photoreceptor having a porous semiconductor fine particle layer on which a specific dye described later is adsorbed on a conductive support. The photoreceptor is designed according to the purpose, and may have a single layer structure or a multilayer structure. The dye in the photoreceptor may be a mixture of many kinds of dyes, but at least the dyes described below are used. In the case where the photosensitive member of the photoelectric conversion element of the present invention, which contains semiconductor fine particles adsorbed with the dye, is used, a photoelectric conversion element having high sensitivity to light in a wide wavelength region can be obtained. When this photoelectric conversion element is used as a photoelectrochemical cell, a high conversion efficiency can be obtained, and a photoelectric conversion element excellent in durability with little reduction in conversion efficiency can be obtained.

一般式（１）中、Ｑは少なくとも四官能以上の芳香族基を示す。芳香族基の例としては、芳香族炭化水素として、ベンゼン、ナフタレン、アントラセン、フェナントレンなどが挙げられ、芳香族へテロ環として、アントラキノン、カルバゾール、ピリジン、キノリン、チオフェン、フラン、キサンテン、チアントレンなどが挙げられ、これらは連結部分以外に置換基を有していてもよい。Ｑで表される芳香族基として、好ましくは芳香族炭化水素であり、さらに好ましくはベンゼン又はナフタレンであり、本発明では、Ｑはフッ素原子または塩素を有してもよい４価のベンゼン環基である。ここで、ＱへのＸ^２とＮ（Ｒ’）の結合は、図示した式中で、Ｎ（Ｒ’）の位置にＸ^２が、Ｘ^２の位置にＮ（Ｒ’）が結合するものも含むものである。
(A) Dye (A1) Dye having the structure of the general formula (1) In the photoelectric conversion element of the present invention, a dye having a structure represented by the following general formula (1) is used. This pigment | dye can be used for photoelectric conversion elements, and has a C5-C18 aliphatic group. The aliphatic group is preferably an alkyl group, an alkenyl group, or an alkynyl group. More preferably, it is an alkyl group or an alkenyl group. Most preferred is an alkyl group, and in the present invention, an alkyl group. Examples include pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, octadecyl, cyclohexyl, 2-ethylhexyl and the like. Among the alkyl groups, branched alkyl groups are preferable, and examples thereof include 2-ethylhexyl, 2-methylhexyl, 2-methylpentyl, 3,5,5-trimethylhexyl, 2-cyclopentaneethyl, 2-cyclohexaneethyl and the like. Can do. By having an alkyl group having 5 to 18 carbon atoms, degradation of the dye due to water and a nucleophilic species, and deterioration in durability due to separation of the dye from the semiconductor fine particles due to water approaching the adsorption point are suppressed. Furthermore, since association between dyes and excessive adsorption can be suppressed, inefficient electron transfer can be suppressed and photoelectric conversion efficiency can be improved.
In the present invention, the following ^{X 1} and ^{X 2} in the molecule, or, below ^{P 1} and ^{P 2} moiety has an alkyl group having 5 to 18 carbon atoms.
However, when the alkyl group having 5 to 18 carbon atoms has the alkyl group in X ¹ and X ² , X ¹ and X ² are CR ¹ R ² , and R ¹ and R ² are 5 carbon atoms. In the case where the P ¹ and P ² moieties have the alkyl group having 5 to 18 carbon atoms, Y is CR ¹⁰ R ¹¹ , and R ¹⁰ and R ¹¹ are 5 to 18 carbon atoms. Or Z is an alkyl group having 5 to 18 carbon atoms.
Here, the alkyl groups are branched, these effects, especially the effect of improving durability is obtained more remarkably.

In general formula (1), Q represents at least a tetrafunctional or higher aromatic group. Examples of aromatic groups include aromatic hydrocarbons such as benzene, naphthalene, anthracene, phenanthrene, and aromatic heterocycles such as anthraquinone, carbazole, pyridine, quinoline, thiophene, furan, xanthene, and thianthrene. These may have a substituent other than the linking moiety. The aromatic group represented by Q, preferably an aromatic hydrocarbon, Ri more preferably benzene or naphthalene der, in the present invention, Q is a fluorine atom or a tetravalent may have a chlorine benzene ring Motodea Ru. Here, ^{X 2} and N (R ') to Q bonds are in the illustrated formula, N (R' ^{which X 2} in position of) the, N (R ') is attached to the position of ^{X 2} Is also included.

X ¹ and X ² each independently represents a sulfur atom, an oxygen atom, or CR ¹ R ² . X ¹ and X ² are preferably a sulfur atom or CR ¹ R ² , and most preferably CR ¹ R ² . Here, R ¹ and R ² each independently represent a hydrogen atom, an aliphatic group, an aromatic group, or a heterocyclic group bonded with a carbon atom. Examples of the heterocyclic group bonded at a carbon atom include pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, isoxazole, isothiazole, pyridine, pyridazine, pyrimidine, and pyran. R ¹ and R ² are preferably an aliphatic group or an aromatic group. The aliphatic group is preferably an alkyl group, an alkenyl group, or an alkynyl group. More preferably, Ri alkyl or alkenyl group der, Ru alkyl der in the present invention. Examples of the alkyl group include a linear or branched alkyl group. Preferably, it is a C5-C18 alkyl group (for example, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, octadecyl, cyclohexyl, 2-ethylhexyl, etc.). Among the alkyl groups, a branched alkyl group is more preferable, and examples thereof include 2-ethylhexyl, 2-methylhexyl, 2-methylpentyl, 3,5,5-trimethylhexyl, 2-cyclopentaneethyl, 2-cyclohexaneethyl and the like. be able to. By having an alkyl group having 5 to 18 carbon atoms, degradation of the dye due to water and a nucleophilic species, and deterioration in durability due to separation of the dye from the semiconductor fine particles due to water approaching the adsorption point are suppressed. Furthermore, since association between dyes and excessive adsorption can be suppressed, inefficient electron transfer can be suppressed and photoelectric conversion efficiency can be improved. Further, since the alkyl group is branched, these effects, particularly the effect of improving the durability, can be obtained more remarkably. Preferred examples of the aromatic group include benzene, naphthalene, anthracene and the like.

R and R ′ each independently represents an aliphatic group, an aromatic group, or a heterocyclic group bonded with a carbon atom, and these may be substituted. Examples of the heterocyclic group bonded at a carbon atom include pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, isoxazole, isothiazole, pyridine, pyridazine, pyrimidine, and pyran. R and R ′ are preferably an aliphatic group or an aromatic group. The number of carbon atoms of the aromatic group is preferably 5 to 16, more preferably 5 or 6. Examples of the unsubstituted aromatic group include phenyl and naphthyl. The aliphatic group is preferably an alkyl group, an alkenyl group, or an alkynyl group. More preferably, it is an alkyl group or an alkenyl group. More preferably, it is a C5-C18 alkyl group (for example, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, octadecyl, cyclohexyl, 2-ethylhexyl, etc.). Among the alkyl groups, branched alkyl groups are preferable, and examples thereof include 2-ethylhexyl, 2-methylhexyl, 2-methylpentyl, 3,5,5-trimethylhexyl, 2-cyclopentaneethyl, 2-cyclohexaneethyl and the like. Can do. By having an alkyl group having 5 to 18 carbon atoms, degradation of the dye due to water and a nucleophilic species, and deterioration in durability due to separation of the dye from the semiconductor fine particles due to water approaching the adsorption point are suppressed. Furthermore, since association between dyes and excessive adsorption can be suppressed, inefficient electron transfer can be suppressed and photoelectric conversion efficiency can be improved. Further, since the alkyl group is branched, these effects, particularly the effect of improving the durability, can be obtained more remarkably.
In the present invention, R and R ′ are alkyl groups.

P ¹ and P ² represent dye residues. The dye residue refers to an atomic group necessary for constituting the dye compound as a whole together with structures other than P ¹ and P ^{2 in} the general formula (1). P ¹ and P ² are bonded directly or via a linking group to constitute a dye of the general formula (1). Examples of the dye (dye compound) formed by P ¹ and P ² include polymethine dyes such as cyanine, merocyanine, rhodacyanine, trinuclear merocyanine, allopolar, hemicyanine, styryl, oxonol, and cyanine, acridine, xanthene, thioxanthene, and the like. Diarylmethine, triarylmethine, coumarin, indoaniline, indophenol, diazine, oxazine, thiazine, diketopyrrolopyrrole, indigo, anthraquinone, perylene, quinacridone, naphthoquinone, bipyridyl, terpyridyl, tetrapyridyl, phenanthroline, etc. .
Preferably, cyanine, merocyanine, rhodacyanine, trinuclear merocyanine, allopolar, hemicyanine, styryl and the like can be mentioned. In this case, cyanine includes those in which the substituent on the methine chain forming the dye forms a squalium ring or a croconium ring. For more information on these dyes, see FM Harmer, “Heterocyclic Compounds-Cyanine Dies and Related Compounds,” John, “Heterocyclic Compounds-Cyanine Soybeans and Reeled Compounds”, John. It is described in, for example, John Wiley & Sons, New York, London, 1964. The general formulas of cyanine, merocyanine and rhodacyanine are preferably those shown in (XI), (XII) and (XIII) of U.S. Pat. No. 5,340,694, pages 21,22. Further, preferably it has a squarylium ring in at least one of the methine chain moiety of the dye residue which is formed by P ¹ and P ^2, which has both are more preferred.

一般式（２）、（３）において、Ｖ^１は水素原子又は置換基を表す。ｎは０〜４の整数を表し、ｎが２以上の場合は、Ｖ^１は同じでも異なっていてもよく、又は互いに結合して環を形成していてもよい。ｎは好ましくは、０〜３であり、より好ましくは０〜２である。
ただし、本発明では、Ｖ ^１ はカルボキシ基、フッ素原子、アルキル基、アルケニル基、アルキニル基、芳香族基、炭素原子で結合するヘテロ環基または２つのＶ ^１ が互いに結合してベンゼン環を形成する基を表す。ｎは０〜２の整数を表す。ｎが２の場合は、Ｖ ^１ は同じでも異なっていてもよい。
In the present invention, P ¹ and P ² are each independently a group represented by the following general formula (2) or (3).

In the general formulas (2) and (3), V ¹ represents a hydrogen atom or a substituent. n represents an integer of 0 to 4, and when n is 2 or more, V ¹ may be the same or different, or may be bonded to each other to form a ring. n is preferably 0 to 3, more preferably 0 to 2.
However, in the present invention, V ¹ is a carboxy group, a fluorine atom, an alkyl group, an alkenyl group, an alkynyl group, an aromatic group, a heterocyclic group bonded by a carbon atom, or two V ¹ are bonded to each other to form a benzene ring. Represents a group. n represents an integer of 0 to 2. When n is 2, V ¹ may be the same or different.

Y represents a sulfur atom, NR ⁹ , or CR ¹⁰ R ¹¹ . R ⁹ represents a hydrogen atom, an aliphatic group, an aromatic group, or a heterocyclic group bonded with a carbon atom. Examples of the heterocyclic group bonded at a carbon atom include pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, isoxazole, isothiazole, pyridine, pyridazine, pyrimidine, and pyran. Preferable examples of R ⁹ are an aliphatic group, preferably an alkyl group, an alkenyl group, or an alkynyl group. More preferably, it is an alkyl group or an alkenyl group. More preferably, it is a C5-C18 alkyl group (for example, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, octadecyl, cyclohexyl, 2-ethylhexyl, etc.). Aromatic groups include benzene, naphthalene, anthracene and the like.
R ¹⁰ and R ¹¹ represent a hydrogen atom, an aliphatic group, an aromatic group, or a heterocyclic group bonded by a carbon atom, and R ¹⁰ and R ¹¹ may be the same or different and are bonded to each other to form a ring. May be formed. Examples of the heterocyclic group bonded at a carbon atom include pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, isoxazole, isothiazole, pyridine, pyridazine, pyrimidine, and pyran. Preferable examples of R ¹⁰ and R ¹¹ are preferably an alkyl group, an alkenyl group or an alkynyl group as the aliphatic group. More preferably, it is an alkyl group or an alkenyl group. More preferably, it is a C5-C18 alkyl group (for example, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, octadecyl, cyclohexyl, 2-ethylhexyl, etc.). Aromatic groups include benzene, naphthalene, anthracene and the like.
However, in the present invention, R ⁹ is an alkyl group, R ¹⁰ and R ¹¹ are alkyl groups, and R ¹⁰ and R ¹¹ may be the same or different.

Z represents an aliphatic group, an aromatic group, or a heterocyclic group bonded with a carbon atom, and may have a substituent. Preferable examples of the substituent include an acidic group, more preferably a group having a carboxyl group. R ^{3 to} R ⁶ and R ⁸ represent a hydrogen atom, an aliphatic group, an aromatic group, or a heterocyclic group, and may have a substituent. Examples of the heterocyclic group bonded at a carbon atom include pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, isoxazole, isothiazole, pyridine, pyridazine, pyrimidine, and pyran. R ^{3 to} R ⁶ and R ⁸ are preferably a hydrogen atom or an aliphatic group. The aliphatic group is preferably an alkyl group, an alkenyl group, or an alkynyl group. More preferably, it is an alkyl group or an alkenyl group. More preferably, it is a C5-C18 alkyl group (for example, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, octadecyl, cyclohexyl, 2-ethylhexyl, etc.). R ^{3 to} R ⁶ and R ⁸ are more preferably a hydrogen atom. R ⁷ represents an oxygen atom or a divalent carbon atom in which the sum of σ _p in the Hammett rule of the two substituents to be bonded is positive.
However, in the present invention, Z is an alkyl group which may be substituted by a carboxy group, a 4-carboxyphenyl group or a 3,4-dicarboxyphenyl group, and R ^{3 to} R ⁶ and R ⁸ are each independently A hydrogen atom or an alkyl group, and R ⁷ is an oxygen atom or a group represented by any one of the following general formulas (10) to (13).

The general formula (1) preferably has an acidic group in at least one of R, R ′, P ¹ and P ² . Here, the acidic group is a substituent having a dissociable proton, and examples thereof include a carboxyl group, a phosphonyl group, a sulfonyl group, a boric acid group, and a group having these groups, and preferably a carboxyl group. It is a group. Further, the acidic group may take a form of releasing a proton and dissociating.

In the general formula (1), W ¹ represents a counter ion when a counter ion is necessary to neutralize the charge. Generally, whether a dye is a cation, an anion, or has a net ionic charge depends on the auxiliary color groups and substituents in the dye. When the dye having the structure of the general formula (1) has a dissociable substituent, it may be dissociated and have a negative charge. In this case, the charge of the whole molecule is neutralized by W ^1.
When W ¹ is a cation, for example, it is an inorganic or organic ammonium ion (for example, a tetraalkylammonium ion or a pyridinium ion) or an alkali metal ion. When W ¹ is an anion, either an inorganic anion or an organic anion may be used. For example, halogen anion (for example, fluoride ion, chloride ion, bromide ion, iodide ion), substituted aryl sulfonate ion (for example, p-toluene sulfonate ion, p-chlorobenzene sulfonate ion), aryl disulfone Acid ion (for example, 1,3-benzenedisulfonic acid ion, 1,5-naphthalenedisulfonic acid ion, 2,6-naphthalenedisulfonic acid ion), alkyl sulfate ion (for example, methyl sulfate ion), sulfate ion, thiocyanate ion Perchlorate ion, tetrafluoroborate ion, picrate ion, acetate ion, trifluoromethanesulfonate ion and the like. Furthermore, an ionic polymer or another dye having a charge opposite to that of the dye may be used as the charge balance counter ion, or a metal complex ion (for example, bisbenzene-1,2-dithiolatonickel (III)) may be used.

Ｖ^１、ｎ、Ｚ及びＹは、前記一般式（２）及び（３）におけるものと同義である。
It is preferable that P ¹ and P ² in the general formula (1) are each independently represented by the following general formula (4) or (5). This results in a dye having a high molar extinction coefficient.

V ^1, n, Z and Y, Ru synonymous der as in the general formula (2) and (3).

In the general formula (4) or (5), Y preferably represents a sulfur atom, NCH ₃ , or C (CH ₃ ) ₂ . Z preferably represents an aliphatic group having 5 to 18 carbon atoms. The aliphatic group is preferably an alkyl group, an alkenyl group, or an alkynyl group. More preferably, it is an alkyl group or an alkenyl group. More preferably, it is a C5-C18 alkyl group (for example, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, octadecyl, cyclohexyl, 2-ethylhexyl, etc.). By making Z an aliphatic group having 5 to 18 carbon atoms, the amount of adsorption per unit area can be improved. The aliphatic group may be substituted.

In the general formulas (2) to (5), V ¹ preferably has an acidic group. An acidic group is a substituent having a dissociable proton. V ¹ only needs to have an acidic group, and the acidic group may be bonded via a linking group. The acidic group is not particularly limited, carboxy sheet group, phosphonic acid group, a sulfo group, arsenate Dorokishiru group, hydroxamic acid group, a phosphoryl group, a phosphonyl group, a sulfino group, a sulfinyl group, a phosphinyl group, a phosphono group, a thiol group and sulfonyl Groups, salts thereof and the like. There is no restriction | limiting in particular as said salt, Any of organic salt and inorganic salt may be sufficient. Typical examples include alkali metal ions (lithium, sodium, potassium, etc.), alkaline earth metal ions (magnesium, calcium, etc.), ammonium, alkylammonium (eg diethylammonium, tetrabutylammonium, etc.), pyridinium, alkylpyridinium ( Examples thereof include salts of methylpyridinium), guanidinium, tetraalkylphosphonium and the like. In the general formula (1), when there are a plurality of acidic groups, they may be the same or different.
The pre-Symbol acidic group, carboxy sheet group, phosphoryl group, or phosphonyl acid group is preferable, rather more preferably is carboxy shea group, the acidic group in V ¹ of the present invention is a carboxy group.
V ¹ was a hydrogen atom, 5-carboxy sheet group, 5-sulfonyl group, to have 5-methyl or 4,5-benzene-fused preferred. Here, the position number is given in the counterclockwise direction with N ⁺ being 1.
Thereby, the effect of improving the molar extinction coefficient or improving the electron injection efficiency is obtained.
The formation in the present invention, V ¹ is a carboxy group, a fluorine atom, an alkyl group, an alkenyl group, an alkynyl group, an aromatic group, a benzene ring bonded to each other is a heterocyclic group, or two V ¹ having a carbon atom bonded to N is an integer of 0 to 2, and when n is 2, V ¹ may be the same or different.

Furthermore, in the general formulas (2) to (5), in addition to V ¹ , Z is preferably a group having an acidic group. Z can be an acidic group similar to V ¹ . The acidic group has an action of adsorbing to the semiconductor fine particles in the dye of the present invention. The number of acidic groups in the dye is preferably 1 or more, and more preferably 1 to 2. Further, by making both V ¹ and Z acidic groups, it is possible to improve durability by improving adsorption power.

The general formula (2) may be represented by the following general formula (6), and the general formula (3) may be represented by the following general formula (7).

In the general formulas (6) and (7), V ¹² represents an acidic group, and at least one of E ^{11 to} E ¹³ represents an electron withdrawing group. p is an integer of 2 or more. The acidic group include the same as those described in the above V ^1.
Examples of the electron withdrawing group are preferably a cyano group, a nitro group, a sulfonyl group, a sulfoxy group, an acyl group, an alkoxycarbonyl group, and a carbamoyl group, more preferably a cyano group, a nitro group, a sulfonyl group, and particularly preferably a cyano group. It is a group.
In General formula (6), p is an integer greater than or equal to 2. p is preferably from 2 to 5, more preferably from 2 to 3. In the general formulas (6) and (7), V ¹² represents an acidic group, and at least one of E ^{11 to} E ¹³ represents an electron withdrawing group, whereby the excited electrons are adsorbed to the semiconductor particle layer. By being strongly attracted to the vicinity, the electrons are efficiently transferred to the semiconductor particle layer, and the effect of improving the photoelectric conversion efficiency can be obtained. Of E ^{11 to} E ¹³ , E ¹¹ and E ¹² are more preferably electron withdrawing groups.
In the present invention, V ¹² is a carboxy group or a sulfo group. E ^{11 to} E ¹³ are a hydrogen atom, a carboxy group, a fluorine atom, an alkyl group, an alkenyl group, an alkynyl group, an aromatic group, or a heterocyclic group bonded with a carbon atom. However, at least one of E ^{11 to} E ¹³ is an electron withdrawing group, and the remaining two are hydrogen atoms . P is 2.

The general formula (2) is preferably represented by the following general formula (8), and the general formula (3) is preferably represented by the following general formula (9).

In the general formula (8) and (9), Y, ^Z, R 3 to R ⁸ is a Y in the general formula (2) or (3), ^Z, and R 3 to R ⁸ synonymous. L is represented by the formulas A to D, and m represents 0 or an integer of 1 or more. When m is 2 or more, they may be different from each other. In the formula A, X _a represents NR _e , O, S. R _e represents a hydrogen atom or a substituent. In Formula A and Formula C, R _{a to} R _d each represent a substituent. Specific examples of the substituent in R _{a to} R _e include those represented by the following substituents.

As the substituent, for example, an aliphatic group, an aromatic group, or a heterocyclic group bonded with a carbon atom is represented, and these may be substituted. Examples of the heterocyclic group bonded at a carbon atom include pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, isoxazole, isothiazole, pyridine, pyridazine, pyrimidine, and pyran. Ra to Re are preferably an aliphatic group or an aromatic group. The number of carbon atoms of the aromatic group is preferably 5 to 16, more preferably 5 or 6. Examples of the unsubstituted aromatic group include phenyl and naphthyl. The aliphatic group is preferably an alkyl group, an alkenyl group, or an alkynyl group. More preferably, it is an alkyl group or an alkenyl group. More preferably, it is a C5-C18 alkyl group (for example, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, octadecyl, cyclohexyl, 2-ethylhexyl, etc.). Among the alkyl groups, branched alkyl groups are preferable, and examples thereof include 2-ethylhexyl, 2-methylhexyl, 2-methylpentyl, 3,5,5-trimethylhexyl, 2-cyclopentaneethyl, 2-cyclohexaneethyl and the like. Can do. By having an alkyl group having 5 to 18 carbon atoms, degradation of the dye due to water and a nucleophilic species, and deterioration in durability due to separation of the dye from the semiconductor fine particles due to water approaching the adsorption point are suppressed. Furthermore, since association between dyes and excessive adsorption can be suppressed, inefficient electron transfer can be suppressed and photoelectric conversion efficiency can be improved. Further, since the alkyl group is branched, these effects, particularly the effect of improving the durability, can be obtained more remarkably.

In the general formula (8), p represents an integer of 2 or more. Rx represents an acidic group. The acidic group include the same as those described in the above V ^1. Rx is preferably a group represented by Formula E.
However, in this invention, m is an integer of 0-3. When m is 2 or more, they may be different from each other. Re is a hydrogen atom or an alkyl group. In Formula A and Formula C, R _{a to} R _d are a hydrogen atom, an alkyl group, or a carboxy group. In the general formula (8), p is 2. Rx is a carboxy group or —CH═C (CN) (COOH).
When the general formula (2) is represented by the general formula (8) and the general formula (3) is represented by the general formula (9), the effect of expanding the absorption region and improving the extinction coefficient can be obtained. The effect of improving photoelectric conversion efficiency can be obtained.

ここで、Ｒｆは、水素原子又は置換基である。置換基としては、脂肪族基、芳香族基、炭素原子で結合するヘテロ環基を挙げることができこれらは置換されていてもよい。好ましい置換基は、脂肪族基、芳香族基である。これにより、短波長側の吸収が強化される。
ただし、本発明では、Ｒｆは水素原子またはアルキル基である。
In the general formulas (3), (5) , (7) and (9), R ⁷ is an oxygen atom or a group represented by any one of the following general formulas (10) to (13). A group represented by any one of formulas (10) to (13) is preferred.

Here, Rf is a hydrogen atom or a substituent. Examples of the substituent include an aliphatic group, an aromatic group, and a heterocyclic group bonded with a carbon atom, and these may be substituted. Preferred substituents are aliphatic groups and aromatic groups. This enhances the absorption on the short wavelength side.
However, in the present invention, Rf is a hydrogen atom or an alkyl group.

これにより、電子注入効率向上の効果が得られる。 In the general formulas (3), (5), and (9), R ⁷ is preferably represented by the following general formula (14) or (15).

As a result, the effect of improving the electron injection efficiency can be obtained.

In the dye of the present invention represented by the general formula (1), the maximum absorption wavelength in a tetrahydrofuran: ethanol = 1: 1 solution is preferably in the range of 670 to 1100 nm, more preferably in the range of 700 to 900 nm.
Although the preferable specific example of a compound represented by General formula (1) of this invention below is shown, this invention is not limited to this.
However, S-4, S-7, S-11, and S-12 are reference examples.

Furthermore, although the preferable specific example of the pigment | dye which has the structure of General formula (6)-(9) of this invention below is shown, this invention is not limited to this.
T-5, T-14, and T-32 are reference examples.

In the specific examples 1 to 4, the basic skeleton A represents any of the following A-1 to A-12, the basic skeleton B represents any of the following B-1 to B-11, and the basic skeleton C is One of the following C-1 to C-4 is shown. Z represents the following Z-1 to Z-5, and the linking group L represents any of the following L-1 to L-12.
In specific examples 1 to 4, the basic skeleton A and the basic skeleton B are bonded to each other with a carbon-carbon double bond between * carbon atoms, and the basic skeleton B and the basic skeleton C are bonded to each other with carbon atoms between ** They are connected by a carbon double bond.

  For example, among the above specific examples, T-2, T-6, T-9, T-10, T-12, T-16, T-17, T-18, T-24, T-30, T- 37 and the structural formula of T-40 to T-50 are as follows.

Moreover, the following pigment | dyes can also be mentioned.

  For the synthesis of the dye having the above structure, Ukrainski Kimicheskii Zhurnal, Vol. 40, No. 3, pp. 253-258, Dies and Pigments, Vol. It can be carried out.

(B) Conductive Support As shown in FIG. 1, in the photoelectric conversion element of the present invention, a photosensitive member 2 in which a dye 21 is adsorbed on porous semiconductor fine particles 22 is formed on a conductive support 1. ing. As will be described later, for example, a dispersion of semiconductor fine particles is applied to a conductive support and dried, and then immersed in the dye solution of the present invention to produce a photoreceptor.
As the conductive support, there can be used a glass or a polymer material having a conductive film layer on the surface, such as a metal that is conductive in the support itself. It is preferable that the conductive support is substantially transparent. Substantially transparent means that the light transmittance is 10% or more, preferably 50% or more, particularly preferably 80% or more. As the conductive support, 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 tetraacetyl 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.

In the present invention, a metal support can be used as a preferable conductive support. As the conductive metal support, a conductive metal support composed of any element belonging to Group 4 to Group 13 is used as the conductive support. Here, Group 4 to Group 13 are those in the long-period periodic table.
The thickness of the conductive metal support in the present invention is preferably 10 μm or more and 2000 μm or less, more preferably 10 μm or more and 1000 μm or less, and particularly preferably 50 μm or more and 500 μm or less. When this thickness is too thick, flexibility is lacking, which may cause trouble when used as a photoelectric conversion element. Moreover, when too thin, it may be damaged during use of the photoelectric conversion element, which is not preferable.
The lower the surface resistance of the conductive metal support used in the present invention, the better. The range of the surface resistance is preferably 10Ω / m ² or less, more preferably 1Ω / m ² or less, and particularly preferably 0.1Ω / m ² or less. When this value is too high, it becomes difficult to energize and the function as a photoelectric conversion element cannot be exhibited.

  As the conductive metal support, at least one selected from the group consisting of titanium, aluminum, copper, nickel, iron, stainless steel, zinc, molybdenum, tantalum, niobium, and zirconium can be preferably used. These metals may be alloys. Of these, titanium, aluminum, copper, nickel, iron, stainless steel, and zinc are more preferred, titanium, aluminum, and copper are more preferred, and titanium and aluminum are most preferred. In the case of aluminum, aluminum alloy wrought material, 1000 series to 7000 series (Light Metal Association: Aluminum Handbook, Light Metal Association, (1978), 26) and the like can be preferably used.

Since the conductive metal support has a small surface resistance and can reduce the internal resistance of the photoelectrochemical cell, a high output battery can be obtained. Further, when a conductive metal support is used, the support does not soften even if the conductive metal support coated with the semiconductor fine particle dispersion described below is heated and dried at a high temperature. . Therefore, a porous semiconductor fine particle layer having a large specific surface area can be formed by appropriately selecting the heating conditions. Thereby, the amount of dye adsorption can be increased, and a photoelectric conversion element with high output and high conversion efficiency can be provided.
Moreover, a porous electroconductive support body can be obtained by apply | coating a semiconductor fine particle dispersion liquid to this metal sheet | seat, and heating after that while winding the metal sheet | seat continuously. Thereafter, the photosensitive layer can be formed on the conductive support by continuously applying the dye of the present invention. By passing through this process, it becomes possible to manufacture a photoelectric conversion element and a photoelectrochemical cell at low cost.

As the conductive metal support of the present invention, a conductive metal layer provided on a polymer material layer can be preferably used. The polymer material layer is not particularly limited, but a material that does not melt and retain its shape when heated after coating the semiconductor fine particle dispersion on the conductive layer is selected. The conductive layer can be produced by laminating the polymer material layer by a conventional method such as extrusion coating.
Examples of the polymer material layer that can be used include tetraacetyl cellulose (TAC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), syndiotactic polystyrene (SPS), polyphenylene sulfide (PPS), and polycarbonate (PC ), Polyarylate (PAr), polysulfone (PSF), polyester sulfone (PES), polyetherimide (PEI), cyclic polyolefin, brominated phenoxy and the like.
As the conductive metal support of the present invention, a polymer material layer provided with a conductive layer is used so that the polymer material layer functions as a protective layer for a photoelectric conversion element or a photoelectrochemical cell. Is possible. If an electrically insulating material is used as the polymer material, the polymer material layer can function not only as a protective layer but also as an insulating layer. Thereby, the insulation of photoelectric conversion element itself can be ensured. When the polymer material layer is used as an insulating layer, it is preferable to use a material having a volume resistivity of 10 ¹⁰ to 10 ²⁰ Ω · cm. More preferably, the volume resistivity is 10 ¹¹ to 10 ¹⁹ Ω · cm. If an electrically conductive material is not blended using the above materials, an insulating layer having a volume resistivity within this range can be obtained. The conductive metal support is preferably substantially transparent. Substantially transparent means that the transmittance of light having a wavelength of 400 to 1200 nm is 10% or more, preferably 50% or more, and particularly preferably 80% or more.

A light management function may be provided on the surface of the conductive metal support. For example, an antireflection film in which high refractive films and low refractive index oxide films are alternately stacked, or a light guide function may be provided.
It is preferable that the conductive support has a function of blocking ultraviolet light. For example, there is a method in which a fluorescent material capable of changing ultraviolet light into visible light is present inside or on the surface of the polymer material layer. Another preferred method is a method using an ultraviolet absorber. A function described in JP-A-11-250944 may be provided on the conductive support.
Since the resistance value of the conductive film increases as the cell area increases, a collecting electrode may be disposed. As a preferable shape and material of the current collecting electrode, those described in JP-A No. 11-266028 can be used. A gas barrier film and / or an ion diffusion preventing film may be disposed between the polymer material layer and the conductive layer. As the gas barrier layer, either a resin film or an inorganic film may be used.

(C) Semiconductor Fine Particle As shown in FIG. 1, in the photoelectric conversion element of the present invention, a photosensitive member 2 in which a dye 21 is adsorbed on a semiconductor fine particle 22 is formed on a conductive support 1. As will be described later, for example, a dispersion of semiconductor fine particles is applied to the conductive support and dried, and then immersed in the dye solution of the present invention to produce a photoreceptor.
As the semiconductor fine particles, metal chalcogenides (for example, oxides, sulfides, selenides, etc.) or perovskite fine particles are preferably used. Preferred examples of the metal chalcogenide include titanium, tin, zinc, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, tantalum oxide, cadmium sulfide, cadmium selenide, and the like. . Preferred perovskites include strontium titanate and calcium titanate. Of these, titanium oxide, zinc oxide, tin oxide, and tungsten oxide are particularly preferable.

In semiconductors, there are an n-type in which carriers involved in conduction are electrons and a p-type in which carriers are holes. In the element of the present invention, n-type is preferable in terms of conversion efficiency. In an n-type semiconductor, in addition to an intrinsic semiconductor (or an intrinsic semiconductor) having no impurity level and equal carrier concentration due to conduction band electrons and valence band holes, the electron carrier concentration is reduced due to structural defects derived from impurities. There are high n-type semiconductors. The n-type inorganic semiconductor preferably used in the present invention is TiO ₂ , TiSrO ₃ , ZnO, Nb ₂ O ₃ , SnO ₂ , WO ₃ , Si, CdS, CdSe, V ₂ O ₅ , ZnS, ZnSe, SnSe, KTaO. ₃ , FeS ₂ , PbS, InP, GaAs, CuInS ₂ , CuInSe ₂ and the like. Of these, the most preferred n-type semiconductors are TiO ₂ , ZnO, SnO ₂ , WO ₃ , and Nb ₂ O ₃ . A semiconductor material in which a plurality of these semiconductors are combined is also preferably used.

  For the purpose of keeping the viscosity of the semiconductor fine particle dispersion high, it is preferable that the average particle size of the primary particles is 2 nm to 50 nm, and the average primary particle size is 2 nm to 30 nm. More preferably, it is a fine particle. Two or more kinds of fine particles having different particle size distributions may be mixed. In this case, the average size of the small particles is preferably 5 nm or less. In addition, for the purpose of improving the light capture rate by scattering incident light, large particles having an average particle size exceeding 50 nm can be added to the above ultrafine particles at a low content. In this case, the content of the large particles is preferably 50% or less, more preferably 20% or less of the mass of particles having an average particle size of 50 nm or less. The average particle size of the large particles added and mixed for the above purpose is preferably 100 nm or more, and more preferably 250 nm or more.

  As a method for producing the semiconductor fine particles, the gel-sol method described in Sakuo Sakuo's “Science of Sol-Gel Method”, Agne Jofu Co., Ltd. (1998) and the like is preferable. Also preferred is a method of producing an oxide by high-temperature hydrolysis of chloride developed by Degussa in an oxyhydrogen salt. When the semiconductor fine particles are titanium oxide, the above sol-gel method, gel-sol method, and high-temperature hydrolysis method in oxyhydrogen salt of chloride are preferred, but Kiyoshi Manabu's “Titanium oxide properties and applied technology” The sulfuric acid method and the chlorine method described in Gihodo Publishing (1997) can also be used. Further, as the sol-gel method, the method described in Journal of American Ceramic Society, Vol. 80, No. 12, 3157-3171 (1997), or the chemistry of Burnside et al. The method described in Materials, Vol. 10, No. 9, pages 2419-2425 is also preferable.

  In addition to this, as a method for producing semiconductor fine particles, for example, as a method for producing titania nanoparticles, preferably, a method by flame hydrolysis of titanium tetrachloride, a combustion method of titanium tetrachloride, hydrolysis of a stable chalcogenide complex, orthotitanic acid Of semiconductor, forming semiconductor fine particles from soluble and insoluble parts, then dissolving and removing soluble parts, hydrothermal synthesis of peroxide aqueous solution, or production of core / shell structured titanium oxide fine particles by sol-gel method A method is mentioned.

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

  Titania may be doped with a nonmetallic element or the like. In addition to the dopant as an additive to titania, an additive may be used on the surface to improve the necking or to prevent reverse electron transfer. Examples of preferred additives include ITO, SnO particles, whiskers, fibrous graphite / carbon nanotubes, zinc oxide necking binders, fibrous materials such as cellulose, metals, organic silicon, dodecylbenzenesulfonic acid, silane compounds, etc. Examples thereof include a mobile binding molecule and a potential gradient dendrimer.

  For the purpose of removing surface defects on titania, titania may be acid-base or redox treated before dye adsorption. Etching, oxidation treatment, hydrogen peroxide treatment, dehydrogenation treatment, UV-ozone, oxygen plasma, or the like may be used.

(D) Semiconductor Fine Particle Dispersion In the present invention, a porous semiconductor fine particle coating layer can be obtained by applying a semiconductor fine particle dispersion to the conductive support and heating appropriately.
In addition to the sol-gel method described above, a method of preparing a semiconductor fine particle dispersion is a method of depositing fine particles in a solvent and using them as they are when synthesizing a semiconductor. Ultrafine particles are irradiated with ultrasonic waves. Or a method of mechanically pulverizing and grinding using a mill or a mortar. As the dispersion solvent, water and / or 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.
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 method for applying the semiconductor fine particle dispersion, a roller method, a dip method, or the like can be used as an application method. Moreover, an air knife method, a blade method, etc. can be used as a metering method. In addition, the application method and the metering method can be made the same part. A rouge method, a curtain method and the like are preferable. It is also preferable to apply by a spin method or a spray method using a general-purpose machine. As the wet printing method, intaglio, rubber plate, screen printing and the like are preferred, including the three major printing methods of letterpress, offset and gravure. From these, a preferred film forming method is selected according to the liquid viscosity and the wet thickness. Further, since the semiconductor fine particle dispersion of the present invention has a high viscosity and has a viscous property, it may have a strong cohesive force and may not be well adapted to the support during coating. In such a case, by performing cleaning and hydrophilization of the surface by UV ozone treatment, the binding force between the applied semiconductor fine particle dispersion and the surface of the conductive support increases, and the semiconductor fine particle dispersion can be easily applied.
The preferred thickness of the entire semiconductor fine particle layer is 0.1 to 100 μm. The thickness of the semiconductor fine particle layer is further preferably 1 to 30 μm, and more preferably 2 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 to 100 g.

The applied semiconductor fine particle layer is subjected to heat treatment in order to enhance the electronic contact between the semiconductor fine particles and to improve the adhesion to the support and to dry the applied semiconductor fine particle dispersion. . By this heat treatment, a porous semiconductor fine particle layer can be formed.
In addition to heat treatment, light energy can also be used. For example, when titanium oxide is used as the semiconductor fine particles, the surface may be activated by applying light absorbed by the semiconductor fine particles such as ultraviolet light, or only the surface of the semiconductor fine particles may be activated by laser light or the like. Can do. By irradiating the semiconductor fine particles with light absorbed by the fine particles, the impurities adsorbed on the particle surface are decomposed by the activation of the particle surface, and can be brought into a preferable state for the above purpose. When heat treatment and ultraviolet light are combined, it is preferable to heat the semiconductor fine particles at 100 ° C. to 250 ° C. or preferably 100 ° C. to 150 ° C. while irradiating the semiconductor fine particles with light absorbed by the fine particles. Thus, by photoexciting the semiconductor fine particles, impurities mixed in the fine particle layer can be washed by photolysis, and physical bonding between the fine particles can be strengthened.

In addition, the semiconductor fine particle dispersion may be applied to the conductive support, and other treatments may be performed in addition to heating and light irradiation. Examples of preferred methods include energization and chemical treatment.
A pressure may be applied after application, and examples of a method for applying pressure include Japanese Patent Application Publication No. 2003-500857. Examples of light irradiation include JP-A No. 2001-357896. Examples of plasma, microwave, and energization include JP-A-2002-353453. Examples of the chemical treatment include JP-A-2001-357896.

The method for coating the above-mentioned semiconductor fine particles on the conductive support is not only the method for coating the above-mentioned semiconductor fine particle dispersion on the conductive support, but also the semiconductor fine particle precursor described in Japanese Patent No. 2664194. A method such as a method of obtaining a semiconductor fine particle film by coating on a conductive support and hydrolyzing with moisture in the air can be used.
Examples of the precursor include (NH ₄ ) ₂ TiF ₆ , titanium peroxide, metal alkoxide / metal complex / metal organic acid salt, and the like.
Also, a method of forming a semiconductor film by applying a slurry in which a metal organic oxide (such as an alkoxide) coexists, and heat treatment, light treatment, etc., a slurry in which an inorganic precursor coexists, titania dispersed in the slurry pH The method which specified the property of particle | grains is mentioned. A binder may be added to these slurries in a small amount, and examples of the binder include cellulose, fluoropolymer, crosslinked rubber, polybutyl titanate, carboxymethyl cellulose and the like.
Techniques related to the formation of semiconductor fine particles or precursor layers thereof include corona discharge, plasma, a method of hydrophilizing by physical methods such as UV, a chemical treatment with alkali, polyethylenedioxythiophene and polystyrenesulfonic acid, polyaniline, etc. For example, formation of an interlayer film for bonding may be mentioned.

  As a method of coating the semiconductor fine particles on the conductive support, (2) the dry method and (3) other methods may be used in combination with the above (1) wet method. (2) As a dry method, JP 2000-231943 A is preferable. (3) As other methods, JP-A-2002-134435 is preferable.

Examples of the dry method include vapor deposition, sputtering, and aerosol deposition method. Further, electrophoresis or electrodeposition may be used.
Moreover, after producing a coating film once on a heat-resistant board | substrate, you may use the method of transcribe | transferring to films, such as a plastics. Preferably, a method of transferring via EVA described in JP-A No. 2002-184475, a semiconductor layer / conductive layer on a sacrificial substrate containing an inorganic salt that can be removed with ultraviolet rays and an aqueous solvent described in JP-A No. 2003-98977 And a method of removing the sacrificial substrate after transfer to an organic substrate.

  The semiconductor fine particles preferably have a large surface area so that many dyes can be adsorbed. For example, in a state where the semiconductor fine particles are coated on the support, the surface area is preferably 10 times or more, more preferably 100 times or more the projected area. Although there is no restriction | limiting in particular in this upper limit, Usually, it is about 5000 times. JP-A-2001-93591 and the like are preferable as the structure of the semiconductor fine particles.

In general, as the thickness of the semiconductor fine particle layer increases, the amount of dye that can be supported per unit area increases, so that the light absorption efficiency increases. However, the diffusion distance of the generated electrons increases, and the loss due to charge recombination also increases. The preferred thickness of the semiconductor fine particle layer varies depending on the use of the device, but is typically 0.1 to 100 μm. When using as a photoelectrochemical cell, it is preferable that it is 1-50 micrometers, and it is more preferable that it is 3-30 micrometers. The semiconductor fine particles may be heated at a temperature of 100 to 800 ° C. for 10 minutes to 10 hours in order to adhere the particles to each other after being applied to the support. When glass is used as the support, the film forming temperature is preferably 400 to 600 ° C.
When a polymer material is used as the support, it is preferably heated after film formation at 250 ° C. or lower. In this case, the film forming method may be any one of (1) a wet method, (2) a dry method, and (3) an electrophoresis method (including an electrodeposition method), preferably (1) a wet method, or ( 2) A dry method, more preferably (1) a wet method.
The coating amount of the semiconductor fine particles per 1 m ² of the support is preferably 0.5 to 500 g, more preferably 5 to 100 g.

In order to adsorb the dye to the semiconductor fine particles, it is preferable to immerse the semiconductor electrode after film formation in the dye adsorbing dye solution comprising the solution and the dye of the present invention. The solution used for the dye solution for dye adsorption can be used without particular limitation as long as it can dissolve the dye for the photoelectric conversion element of the present invention. For example, an organic solvent such as ethanol, methanol, isopropanol, toluene, t-butanol, acetonitrile, acetone, n-butanol can be used. Among these, ethanol and toluene can be preferably used. The organic solvent can be used alone or a mixture of a plurality of organic solvents. The concentration of the dye is preferably 0.01 mmol / L to 1.0 mmol / L so as to be uniformly adsorbed to the semiconductor fine particles. More preferably, it is 0.1 mmol / L-1.0 mmol / L.
The dye solution for dye adsorption comprising the solution and the dye of the present invention may be heated to 50 ° C. to 100 ° C. as necessary. The adsorption of the dye may be performed before or after application of the semiconductor fine particles. Further, the semiconductor fine particles and the dye may be applied and adsorbed simultaneously. Unadsorbed dye is removed by washing. When baking a coating film, it is preferable to adsorb | suck a pigment | dye after baking. It is particularly preferable that the dye is quickly adsorbed after the baking and before water adsorbs on the surface of the coating film. You may mix the pigment | dye which has another structure in the range which does not impair the meaning of this invention. When mixing the dyes, it is necessary to prepare a dye solution for dye adsorption so that all the dyes are dissolved.

The total amount of the dye used is preferably 0.01 to 100 mmol, more preferably 0.1 to 50 mmol, particularly preferably 0.1 to 10 mmol, per 1 m ² of the support. In this case, it is preferable that the usage-amount of the pigment | dye of this invention shall be 5 mol% or more.
Further, the adsorption amount of the dye to the semiconductor fine particles is preferably 0.001 to 1 mmol, more preferably 0.1 to 0.5 mmol, with respect to 1 g of the semiconductor fine particles.
By using such a dye amount, 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.

Further, a colorless compound may be co-adsorbed for the purpose of reducing the interaction between dyes such as association. Examples of the hydrophobic compound to be co-adsorbed include steroid compounds having a carboxyl group (for example, cholic acid and pivaloyl acid).
After adsorbing the dye, the surface of the semiconductor fine particles may be treated with amines. Preferred amines include 4-tert-butyl pyridine, polyvinyl pyridine and the like. These may be used as they are in the case of a liquid, or may be used by dissolving in an organic solvent.

  The counter electrode functions as a positive electrode of the photoelectrochemical cell. The counter electrode is usually synonymous with the conductive support described above, but the support is not necessarily required in a configuration in which the strength is sufficiently maintained. However, having a support is advantageous in terms of hermeticity. Examples of the material for the counter electrode include platinum, carbon, conductive polymer, and the like. Preferable examples include platinum, carbon, and conductive polymer.

As the structure of the counter electrode, a structure having a high current collecting effect is preferable. Preferable examples include JP-A-10-505192.
As the light receiving electrode, a composite electrode such as titanium oxide and tin oxide (TiO ₂ / SnO ₂ ) may be used. Examples of the mixed electrode of titania include those described in Japanese Patent Application Laid-Open No. 2000-111393. Examples of the mixed electrode other than titania include those described in JP-A Nos. 2001-185243 and 2003-282164.

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

A short-circuit prevention layer is preferably formed between the conductive support 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 those described in JP-A No. 06-507999.
In order to prevent contact between the light receiving electrode and the counter electrode, it is preferable to use a spacer or a separator. Preferable examples include those described in JP-A-2001-283941.

(E) Electrolyte As a typical redox couple, for example, a combination of iodine and iodide (for example, lithium iodide, tetrabutylammonium iodide, tetrapropylammonium iodide, etc.), alkyl viologen (for example, methyl viologen chloride, hexyl) A combination of viologen bromide, benzyl viologen tetrafluoroborate) and its reduced form, a combination of polyhydroxybenzenes (eg, hydroquinone, naphthohydroquinone, etc.) and its oxidant, and a divalent and trivalent iron complex (eg, red blood salt) And a combination of yellow blood salt). Of these, a combination of iodine and iodide is preferred. As the organic solvent for dissolving them, an aprotic polar solvent (for example, acetonitrile, propylene carbonate, ethylene carbonate, dimethylformamide, dimethyl sulfoxide, sulfolane, 1,3-dimethylimidazolinone, 3-methyloxazolidinone, etc.) is preferable. Examples of the polymer used for the matrix of the gel electrolyte include polyacrylonitrile and polyvinylidene fluoride. Examples of the molten salt include those imparted with fluidity at room temperature by mixing polyethylene oxide with lithium iodide and at least one other lithium salt (for example, lithium acetate, lithium perchlorate, etc.). It is done. In this case, the amount of the polymer added is 1 to 50% by mass. Moreover, (gamma) -butyrolactone may be contained in electrolyte solution, and thereby the diffusion efficiency of iodide ion becomes high and conversion efficiency improves.

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

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

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

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

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

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

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

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

  A solid charge transport layer such as a p-type semiconductor or a hole transport material may be used instead of the above liquid electrolyte and quasi-solid electrolyte. An organic hole transport material may be used as the solid charge transport layer. The hole transport layer is preferably a conductive polymer such as polythiophene, polyaniline, polypyrrole, and polysilane, and a spiro compound in which two rings share a central element having a tetrahedral structure such as C or Si, a triarylamine, etc. Aromatic amine derivatives, triphenylene derivatives, nitrogen-containing heterocyclic derivatives, liquid crystal cyano derivatives are exemplified.

  Since the redox couple becomes an electron carrier, a certain concentration is required. The preferred concentration is 0.01 mol / L or more in total, more preferably 0.1 mol / L, 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.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to these.

[Preparation of dye]
0.45 g of the following (SA-1) and 0.26 g of the following (SB-1) were mixed in a mixed solvent of 10 mL of 1-butanol and 10 mL of toluene and stirred while heating at 100 ° C. for 4 hours. The obtained crystals were separated by suction filtration and purified by silica gel column chromatography to prepare 0.26 g of the dye S-14 described above.

[Experiment 1]
(Preparation of photoelectric conversion element)
The photoelectric conversion element shown in FIG. 1 was produced as follows.
On the glass substrate, tin oxide doped with fluorine was formed as a transparent conductive film by sputtering, and this was scribed with a laser to divide the transparent conductive film into two parts. Among these, anatase-type titanium oxide particles were sintered on one conductive film to produce a light receiving electrode. Thereafter, a dispersion containing silica particles and rutile titanium oxide at a ratio of 40:60 (mass ratio) was applied and sintered on the light-receiving electrode to form an insulating porous body. The coating amount of the semiconductor fine particles was 20 g / m ^2, and then a carbon electrode was formed as a counter electrode.
Next, it was immersed for 48 hours in the ethanol solution (each ^3x10 < ^-4 > mol / L) of the pigment | dye described in Table 1 below. The glass dyed with the sensitizing dye was immersed in a 10% ethanol solution of 4-tert-butylpyridine for 30 minutes, then washed with ethanol and naturally dried. The thickness of the obtained photoreceptor was 10 μm. The amount of the dye was appropriately selected from the range of 0.1 to 10 mmol / m ² depending on the kind of the dye.
As the electrolytic solution, a methoxypropionitrile solution of dimethylpropylimidazolium iodide (0.5 mol / L) and iodine (0.1 mol / L) was used.

(Measurement of maximum absorption wavelength of dye)
The maximum absorption wavelength of the dye used was measured. The results are shown in Table 1. The maximum absorption wavelength was measured with a spectrophotometer (U-4100 (trade name), manufactured by Hitachi High-Tech), and the solution was adjusted to a concentration of 2 μM using THF: ethanol = 1: 1.
(Measurement of photoelectric conversion efficiency)
Simulated sunlight containing no ultraviolet rays was generated by passing the light of a 500 W xenon lamp (manufactured by Ushio) through an AM1.5G filter (manufactured by Oriel) and a sharp cut filter (KenkoL-42, trade name). The intensity of this light was 89 mW / cm ² . The produced photoelectric conversion element was irradiated with this light, and the photoelectric conversion characteristics were measured with a current-voltage measuring device (Keithley 238 type, trade name).
The results of measuring the initial value of the conversion efficiency of the photoelectrochemical cell are shown as conversion efficiency in Table 1 below. Conversion efficiency of 2.5% or more is indicated as ◎, 1% or more and less than 2.5% is indicated as ◯, 0.3% or more and less than 1% is indicated as △, and less than 0.3% is indicated as ×. The conversion efficiency of 0.3% or more was accepted and the conversion efficiency of less than 0.3% was rejected. Further, a decrease in conversion efficiency after 500 hours with respect to the initial value of conversion efficiency was evaluated as durability. When the result is 90% or more, ◎, 60% or more and less than 90% are evaluated as ◯, 40% or more and less than 60% are evaluated as △, and less than 40% are evaluated as ×. On the other hand, a conversion efficiency after 500 hours of 60% or more was accepted, and a conversion efficiency of less than 60% was rejected.

表１からわかるように、本発明の色素を用いた光電気化学電池は、変換効率の初期値が合格レベルであり、さらに５００時間経過後の変換効率が初期値の６０％以上と、優れた耐久性を示した。
これに対して、比較色素を用いた場合には、変換効率の初期値が合格レベルであるが、耐久性に問題があることがわかった。 In Experiments 1 to 10, the following A-1 and A-2 were used as comparative dyes.

As can be seen from Table 1, in the photoelectrochemical cell using the dye of the present invention, the initial value of the conversion efficiency was an acceptable level, and the conversion efficiency after 500 hours passed was excellent at 60% or more of the initial value. Shows durability.
On the other hand, when the comparative dye was used, it was found that the initial value of the conversion efficiency was an acceptable level, but there was a problem with durability.

[Experiment 2]
An ITO film was produced on a glass substrate, and an FTO film was laminated thereon to produce a transparent conductive film. Then, a transparent electrode plate was obtained by forming an oxide semiconductor porous film on the transparent conductive film. And the photoelectrochemical cell was produced using the transparent electrode plate, and conversion efficiency was measured. The method is as follows (1)-(5).

(1) Preparation of raw material solution for ITO (indium-tin-oxide) film Indium (III) tetrahydrate 5.58 g and tin (II) chloride dihydrate 0.23 g were dissolved in 100 mL of ethanol. Thus, a raw material compound solution for the ITO film was obtained.

(2) Preparation of FTO (Fluorine Doped Tin Oxide) Film Raw Material Compound Solution 0.701 g of tin (IV) chloride pentahydrate was dissolved in 10 mL of ethanol, and 0.592 g of a saturated aqueous solution of ammonium fluoride was added thereto. This mixture was subjected to an ultrasonic cleaning machine for about 20 minutes and completely dissolved to obtain a raw material compound solution for an FTO film.

(3) Preparation of ITO / FTO transparent conductive film The surface of a heat-resistant glass plate having a thickness of 2 mm was chemically washed and dried, and then this glass plate was placed in a reactor and heated with a heater. When the heating temperature of the heater reached 450 ° C., the raw material compound solution for ITO film obtained in (1) was adjusted from a nozzle having a diameter of 0.3 mm to a pressure of 0.06 MPa and a distance to the glass plate of 400 mm, 25 Sprayed for a minute.
After spraying the raw material compound solution for ITO film, 2 minutes passed (ethanol was sprayed on the glass substrate surface during this period to suppress the rise of the substrate surface temperature), and the heating temperature of the heater became 530 ° C. Occasionally, the FTO membrane raw material compound solution obtained in (2) was sprayed for 2 minutes 30 seconds under the same conditions. As a result, a transparent electrode plate was obtained in which an ITO film having a thickness of 530 nm and an FTO film having a thickness of 170 nm were sequentially formed on the heat-resistant glass plate.
For comparison, similarly, a transparent electrode plate in which only a 530 nm thick ITO film is formed on a heat resistant glass plate having a thickness of 2 mm and a transparent electrode plate in which only a 180 nm thick FTO film is similarly formed are formed. Each was produced.
These three types of transparent electrode plates were heated in a heating furnace at 450 ° C. for 2 hours.

(4) Production of photoelectrochemical cell Next, a photoelectrochemical cell having the structure shown in FIG. 2 of Japanese Patent No. 4260494 was produced using the above three types of transparent electrode plates. The oxide semiconductor porous film is formed by dispersing titanium oxide fine particles having an average particle diameter of about 230 nm in acetonitrile to form a paste, applying the paste to the transparent electrode 11 by a bar coating method to a thickness of 15 μm, and drying to 450 ° C. And baked for 1 hour. Thereafter, the dyes listed in Table 2 were supported on the oxide semiconductor porous membrane.
Further, a conductive substrate in which an ITO film and an FTO film were laminated on a glass plate was used for the counter electrode, and an electrolyte solution made of a non-aqueous solution of iodine / iodide was used for the electrolyte layer. The planar dimension of the photoelectrochemical cell was 25 mm × 25 mm.

(5) Evaluation of photoelectrochemical cell The photoelectrochemical cell obtained in (4) was irradiated with simulated sunlight (AM1.5), the photoelectric conversion characteristics were measured in the same manner as in Experiment 1, and the conversion efficiency Asked. The results are shown in Table 2. About conversion efficiency, the relative value when the sample number 2-9 was set to 1 was shown. With respect to durability, the conversion efficiency after 500 hours with respect to the initial value of conversion efficiency is 90% or more, ◎, 60% or more and less than 90% ○, 40% or more and less than 60% △, Those less than 40% were evaluated as x. When the conversion efficiency after 500 hours was 60% or more with respect to the initial value of the conversion efficiency, it was determined to be acceptable, and when the conversion efficiency was less than 60%, it was rejected.

As can be seen from Table 2, when the conductive layer is only the ITO film or only the FTO film, the conversion efficiency is lowered even in the photoelectrochemical cell of the present invention, and the conductive layer is formed on the ITO film. In the case, the conversion efficiency tended to increase. The tendency was the same for the photoelectrochemical cell of the comparative example.
Nevertheless, all of the photoelectrochemical cells of the present invention show excellent durability with a conversion efficiency of 60% or more after the elapse of 500 hours, whereas the photoelectrochemical cells of the comparative examples have an elapse of 500 hours. Later conversion efficiency was less than 40%, and it was found that there was a problem in durability.

[Experiment 3]
A collecting electrode was arranged on the FTO film to produce a photoelectrochemical cell, and the conversion efficiency was evaluated. Evaluation was made into two types, test cell (i) and test cell (iv) as follows.

(Test cell (i))
The surface of a heat-resistant glass plate of 100 mm × 100 mm × 2 mm is chemically cleaned and dried, then this glass plate is placed in a reactor, heated with a heater, and then FTO (fluorine-doped tin oxide) used in Experiment 2 above The film raw material compound solution was sprayed from a nozzle having a diameter of 0.3 mm at a pressure of 0.06 MPa and a distance to the glass plate of 400 mm for 25 minutes to prepare a glass substrate with an FTO film.
On the surface, grooves having a depth of 5 μm were formed in a lattice circuit pattern by an etching method. After pattern formation by photolithography, etching was performed using hydrofluoric acid. A metal conductive layer (seed layer) was formed by sputtering to enable plating formation, and a metal wiring layer was further formed by additive plating. The metal wiring layer was formed in a convex lens shape from the transparent substrate surface to a height of 3 μm. The circuit width was 60 μm. From this, an FTO film having a thickness of 400 nm was formed as the shielding layer 5 by the SPD method to obtain an electrode substrate (i). The cross-sectional shape of the electrode substrate (i) was as shown in FIG. 2 in JP-A No. 2004-146425.

A titanium oxide dispersion having an average particle size of 25 nm was applied and dried on the electrode substrate (i), and heated and sintered at 450 ° C. for 1 hour. This was immersed in an ethanol solution of the dye shown in Table 3 for 40 minutes to carry the dye. In addition, preliminary studies were conducted on the solubility of the dye used in the present invention in various organic solvents. As a result, it was found that it could be dissolved in toluene. Therefore, as shown in Table 3, a solution infiltrated and supported in a toluene solution for 40 minutes was also prepared.
The platinum sputtered FTO substrate and the substrate were placed facing each other through a 50 μm-thick thermoplastic polyolefin resin sheet, and the resin sheet portion was heat-melted to fix the bipolar plates.
A methoxyacetonitrile solution containing 0.5M iodide and 0.05M iodine as the main components was injected from the electrolyte solution inlet previously opened on the platinum sputter electrode side, and filled between the electrodes. It was. Furthermore, the peripheral part and the electrolyte solution injection port were sealed with an epoxy-based sealing resin, and a silver paste was applied to the current collecting terminal part to obtain a test cell (i). The test cell (i) was irradiated with AM1.5 simulated sunlight in the same manner as in Experiment 1, and the conversion efficiency was measured. The results are shown in Table 3.

(Test cell (iv))
A glass substrate with a 100 × 100 mm FTO film was prepared in the same manner as in the test cell (i). On the FTO glass substrate, a metal wiring layer (gold circuit) was formed by additive plating. The metal wiring layer (gold circuit) was formed in a lattice shape on the substrate surface, and had a circuit width of 50 μm and a circuit thickness of 5 μm. On this surface, an FTO film having a thickness of 300 nm was formed as a shielding layer by the SPD method to obtain an electrode substrate (iv). When the cross section of the electrode substrate (iv) was confirmed using SEM-EDX, there was a sneaking in which seems to be caused by the bottom of the plating resist at the bottom of the wiring, and the shadow portion was not covered with FTO.
A test cell (iv) was produced in the same manner as the test cell (i) using the electrode substrate (iv). AM1.5 simulated sunlight was irradiated in the same manner as in Experiment 1, and the conversion efficiency was measured. The result of the initial value of the conversion efficiency is shown in Table 3 as the conversion efficiency.
Conversion efficiency of 2.5% or more is indicated as ◎, 1% or more and less than 2.5% is indicated as ◯, 0.3% or more and less than 1% is indicated as △, and less than 0.3% is indicated as ×. The conversion efficiency of 0.3% or more was accepted and the conversion efficiency of less than 0.3% was rejected. Further, the conversion efficiency after 500 hours with respect to the initial value of conversion efficiency is 90% or more, ◎, 60% or more and less than 90%, ◯, 40% or more and less than 60%, or less than 40%. The product was evaluated as x, and the durability is shown in Table 3. When the conversion efficiency after 500 hours was 60% or more with respect to the initial value of the conversion efficiency, it was determined to be acceptable, and when the conversion efficiency was less than 60%, it was rejected.

  From Table 3, the conversion efficiency of the test cell using the dye of the present invention showed a high value of 1% or more. Moreover, it turned out that conversion efficiency can be made high by selecting suitably the solvent used for a pigment | dye solution (contrast of sample 3-1, 3-2 and sample 3-3, 3-4). When the comparative dye is used, the initial value of the conversion efficiency may be as high as in the present invention, but the conversion efficiency after a lapse of 500 hours is greatly reduced, whereas when the dye of the present invention is used, The durability was remarkably reduced and excellent characteristics were exhibited.

[Experiment 4]
Peroxotitanic acid and titanium oxide fine particles were prepared, and an oxide semiconductor film was prepared using them. Using this, a photoelectrochemical cell was produced and evaluated.
(Production of photoelectrochemical cell (A))
(1) Preparation of coating liquid (A1) for forming an oxide semiconductor film 5 g of titanium hydride is suspended in 1 liter of pure water, 400 g of a 5 mass% hydrogen peroxide solution is added over 30 minutes, and then 80 A solution of peroxotitanic acid was prepared by heating to ° C and dissolution. 90% by volume was taken from the total amount of this solution, adjusted to pH 9 by adding concentrated aqueous ammonia, placed in an autoclave, hydrothermally treated at 250 ° C. for 5 hours under saturated vapor pressure, and titania colloidal particles (A2) Was prepared. The obtained titania colloidal particles were anatase type titanium oxide having high crystallinity by X-ray diffraction.

Next, the obtained titania colloidal particles (A2) was concentrated to 10 wt%, the peroxotitanic acid solution were mixed, the titanium of the mixed solution TiO ₂ terms, TiO ₂ mass of 30 mass% Then, hydroxypropylcellulose was added as a film formation aid so that a coating solution for forming a semiconductor film (A1) was prepared.

(2) Production of Oxide Semiconductor Film (A3) Next, the coating liquid (A1) is applied on a transparent glass substrate on which fluorine-doped tin oxide is formed as an electrode layer, followed by natural drying, followed by a low-pressure mercury lamp. It was used to irradiate ultraviolet rays of 6000 mJ / cm ² to decompose the peroxo acid and harden the coating film. The coating film was heated at 300 ° C. for 30 minutes to decompose and anneal the hydroxypropyl cellulose to form an oxide semiconductor film (A3) on the glass substrate.

(3) Adsorption of dye to oxide semiconductor film (A3) Next, an ethanol solution having a concentration of 3 × 10 ⁻⁴ mol / L of the dye of the present invention was prepared as a spectral sensitizing dye. This dye solution was applied onto the metal oxide semiconductor film (A3) with a 100 rpm spinner and dried. This coating and drying process was performed five times.

(4) Preparation of electrolyte solution In a mixed solvent having a volume ratio of acetonitrile and ethylene carbonate of 1: 5, tetrapropylammonium iodide is adjusted to a concentration of 0.46 mol / L and iodine to a concentration of 0.07 mol / liter. To prepare an electrolyte solution.

(5) Production of photoelectrochemical cell (A) The glass substrate on which the oxide semiconductor film (A3) adsorbed with the dye produced in (2) is formed is used as one electrode, and fluorine doped as the other electrode. The tin oxide was formed as an electrode. A transparent glass substrate carrying platinum thereon was disposed oppositely, the side surfaces were sealed with resin, and the electrolyte solution (4) was sealed between the electrodes. Further, the photoelectrochemical cell (A) was produced by connecting the electrodes with lead wires.

(Production of photoelectrochemical cell (B))
Oxide semiconductor film (except that it was irradiated with ultraviolet rays to decompose peroxo acid and harden the film, followed by Ar gas ion irradiation (Nisshin Electric Co., Ltd .: ion implantation apparatus, 200 eV irradiation for 10 hours) An oxide semiconductor film (B3) was formed in the same manner as in A3).
Similarly to the oxide semiconductor film (A3), the dye was adsorbed to the oxide semiconductor film (B3). Then, the photoelectrochemical cell (B) was produced by the same method as the photoelectrochemical cell (A).

(Production of photoelectrochemical cell (C))
18.3 g of titanium tetrachloride was diluted with pure water to obtain an aqueous solution containing 1.0% by mass in terms of TiO ₂ . While stirring this aqueous solution, 15% by mass of aqueous ammonia was added to obtain a white slurry having a pH of 9.5. This slurry was washed by filtration to obtain a 10.2% by mass hydrated titanium oxide gel cake in terms of TiO ₂ . This cake was mixed with 400 g of a 5 mass% hydrogen peroxide solution, and then heated to 80 ° C. to dissolve to prepare a peroxotitanic acid solution. 90% by volume is taken from the total amount of this solution, and concentrated ammonia water is added to adjust the pH to 9, and the mixture is placed in an autoclave, hydrothermally treated at 250 ° C. for 5 hours under saturated vapor pressure, and titania colloid particles (C2 ) Was prepared.
Next, an oxide semiconductor film (C3) is formed in the same manner as the oxide semiconductor film (A3) using the peroxotitanic acid solution obtained above and titania colloidal particles (C2), and the metal oxide semiconductor film In the same manner as (A3), the dye of the present invention was adsorbed as a spectral sensitizing dye. Then, the photoelectrochemical cell (C) was produced by the same method as the photoelectrochemical cell (A).

(Production of photoelectrochemical cell (D))
18.3 g of titanium tetrachloride was diluted with pure water to obtain an aqueous solution containing 1.0% by mass in terms of TiO ₂ . While stirring this, 15% by mass of ammonia water was added to obtain a white slurry having a pH of 9.5. This slurry was filtered and washed, suspended in pure water to obtain a 0.6 mass% hydrated titanium oxide gel slurry as TiO ₂ , adjusted to pH 2 by adding hydrochloric acid thereto, put in an autoclave, and stirred at 180 ° C. for 5 hours. The titania colloidal particles (D2) were prepared by performing hydrothermal treatment under saturated vapor pressure for a period of time.

Next, titania colloidal particles (D2) are concentrated to 10% by mass, and hydroxypropylcellulose is added as a film forming aid so as to be 30% by mass in terms of TiO ₂ to form a semiconductor film. A coating solution was prepared. Next, the coating solution is applied onto a transparent glass substrate on which fluorine-doped tin oxide is formed as an electrode layer, dried naturally, and subsequently irradiated with 6000 mJ / cm ² of ultraviolet rays using a low-pressure mercury lamp to form a film. Cured. Furthermore, it decomposed | disassembled and annealed by heating for 30 minutes at 300 degreeC, and the oxide semiconductor film (D3) was formed.

  Next, the dye of the present invention was adsorbed as a spectral sensitizing dye in the same manner as the oxide semiconductor film (A3). Then, the photoelectrochemical cell (D) was produced by the method similar to a photoelectrochemical cell (A).

  For the photoelectrochemical cells (A) to (D), simulated sunlight (AM1.5) was irradiated, photoelectric conversion characteristics were measured by the same method as in Experiment 1, and conversion efficiency was obtained. The result of the initial value of the conversion efficiency is shown in Table 4 as the conversion efficiency. Conversion efficiency of 2.5% or more is indicated as ◎, 1% or more and less than 2.5% is indicated as ◯, 0.3% or more and less than 1% is indicated as △, and less than 0.3% is indicated as ×. The conversion efficiency of 0.3% or more was accepted and the conversion efficiency of less than 0.3% was rejected. Further, the conversion efficiency after 500 hours with respect to the initial value of conversion efficiency is 90% or more, ◎, 60% or more and less than 90%, ◯, 40% or more and less than 60%, or less than 40%. A thing was evaluated as x and the value is shown in Table 4 as durability. When the conversion efficiency after 500 hours was 60% or more with respect to the initial value of the conversion efficiency, it was determined to be acceptable, and when the conversion efficiency was less than 60%, it was rejected.

As can be seen from Table 4, in the photoelectrochemical cell using the dye of the present invention, the initial value of the conversion efficiency was an acceptable level, and the conversion efficiency after 500 hours passed was excellent at 60% or more of the initial value. Shows durability.
On the other hand, when the comparative dye was used, it was found that the initial value of the conversion efficiency was an acceptable level, but there was a problem with durability.

[Experiment 5]
Titanium oxide was prepared by changing the method, an oxide semiconductor film was produced from the obtained titanium oxide, and a photoelectrochemical cell was evaluated.

(1) Preparation of titanium oxide by heat treatment method (titanium oxide 1 (blue kite type) etc.)
Using a commercially available anatase-type titanium oxide (trade name ST-01, manufactured by Ishihara Sangyo Co., Ltd.), this is heated to about 900 ° C. to be converted into a brookite-type titanium oxide, and further heated to about 1,200 ° C. Rutile type titanium oxide was used. Respectively, comparative titanium oxide 1 (anatase type), titanium oxide 1 (blue kite type), and comparative titanium oxide 2 (rutile type) are used.

(2) Synthesis of titanium oxide by wet method (titanium oxide 2 (blue kite type))
954 ml of distilled water is charged into a reaction vessel equipped with a reflux condenser and heated to 95 ° C. While maintaining the stirring speed at about 200 rpm, 46 ml of an aqueous solution of titanium tetrachloride (Ti content: 16.3 mass%, specific gravity 1.59, purity 99.9%) was added to this distilled water at a speed of about 5.0 ml / min. It was dripped at the reaction tank. At this time, care was taken not to lower the temperature of the reaction solution. As a result, the titanium tetrachloride concentration was 0.25 mol / liter (2% by mass in terms of titanium oxide). In the reaction vessel, the reaction solution started to become cloudy immediately after dropping, but kept at the same temperature. After the dropping was completed, the temperature was further raised and heated to the vicinity of the boiling point (104 ° C.). The reaction was terminated.

  The sol obtained by the reaction was filtered, and then powdered using a vacuum dryer at 60 ° C. As a result of quantitative analysis of this powder by X-ray diffractometry, the ratio of (peak intensity on the surface of blue kite type 121) / (peak intensity at the position where the three overlap) is 0.38, (rutile main peak intensity) / The ratio (peak intensity at the position where the three lines overlap) was 0.05. From these, the titanium oxide was crystallinity of about 70.0% by mass for the brookite type, about 1.2% by mass for the rutile type, and about 28.8% by mass for the anatase type. Further, when the fine particles were observed with a transmission electron microscope, the average particle diameter of the primary particles was 0.015 μm.

(Titanium oxide 3 (Blue Kite type))
An aqueous solution of titanium trichloride (Ti content: 28% by mass, specific gravity 1.5, purity 99.9%) was diluted with distilled water to obtain a solution having a concentration of 0.25 mol / L in terms of titanium concentration. At this time, it was ice-cooled so as not to increase the liquid temperature and kept at 50 ° C. or lower. Next, 500 ml of this solution was put into a reaction tank equipped with a reflux condenser, and ozone gas with a purity of 80% was bubbled from the ozone gas generator at 1 L / min while heating at 85 ° C. to carry out an oxidation reaction. This state was maintained for 2 hours to complete the reaction. The obtained sol was filtered and vacuum-dried to obtain a powder. As a result of quantitative analysis of this powder by X-ray diffractometry, the ratio of (peak intensity on the surface of blue kite type 121) / (peak intensity at the position where the three overlap) is 0.85, (rutile main peak intensity) / The ratio (peak intensity at the position where the three lines overlap) was 0. From these, the titanium dioxide was about 98% by mass for the blue kite type, 0% by mass for the rutile type, 0% by mass for the anatase type, and about 2% was amorphous. Further, when the fine particles were observed with a transmission electron microscope, the average particle diameter of the primary particles was 0.05 μm.

(Production and evaluation of photoelectrochemical cells)
A photoelectrochemical cell using the photoelectric conversion element having the structure shown in FIG. 1 described in JP-A No. 2000-340269 was produced by the following method using titanium oxides 1 to 3 prepared by the above method as a semiconductor.
A glass substrate was coated with fluorine-doped tin oxide to form a conductive transparent electrode. A paste using each titanium oxide particle as a raw material was formed on the electrode surface, applied to a thickness of 50 μm by a bar coating method, and then baked at 500 ° C. to form a thin layer having a thickness of about 20 μm.

As examined in Experiment 1, since the dye used in the present invention was found to be highly soluble in various organic solvents, ethanol was used as the solvent, and the dye solution having different concentrations was evaluated. In the case of the dye used in the present invention, two-level dye solutions of 3 × 10 ⁻⁴ M and 6 × 10 ⁻⁴ M were used. In the case of the comparative dye, since the solubility in a solvent was low and a 6 × 10 ⁻⁴ M solution could not be prepared, the evaluation was performed using only a 3 × 10 ⁻⁴ M dye solution.
An ethanol solution having the dye concentrations shown in Table 5 was prepared, and the glass substrate on which the titanium oxide thin layer was formed was immersed in this solution, and kept at room temperature for 12 hours. As a result, these dyes were adsorbed onto a thin layer of titanium oxide.

A photoelectric conversion element having a configuration shown in FIG. 1 of JP-A No. 2000-340269 was produced using an iodine salt of tetrapropylammonium as an electrolytic solution and an acetonitrile solution of lithium iodide and using platinum as a counter electrode. In photoelectric conversion, light from a 160 W high-pressure mercury lamp (the infrared portion was cut by a filter) was irradiated to the above-described element, and the initial value of conversion efficiency was measured in the same manner as in Experiment 1. The results are shown in Table 5 as conversion efficiency.
Conversion efficiency of 2.5% or more is indicated as ◎, 1% or more and less than 2.5% is indicated as ◯, 0.3% or more and less than 1% is indicated as △, and less than 0.3% is indicated as ×. The conversion efficiency of 0.3% or more was accepted and the conversion efficiency of less than 0.3% was rejected. In addition, the conversion efficiency after 500 hours with respect to the initial value of conversion efficiency is 90% or more, ◎, 60% to less than 90% ○, 40% to less than 60% △, less than 40% Things were evaluated as x. The results are shown in Table 5 as durability. When the conversion efficiency after 500 hours was 60% or more with respect to the initial value of the conversion efficiency, it was determined to be acceptable, and when the conversion efficiency was less than 60%, it was rejected.

As can be seen from Table 5, it was found that when the dye of the present invention was used, the initial value of the conversion efficiency was increased by increasing the concentration of the dye solution. This seems to be because the adsorption of the dye to titanium oxide can be increased by increasing the concentration of the dye solution. Even when the comparative dye was used, the initial value of the conversion efficiency was acceptable.
However, with respect to durability, when the comparative dye was used, all failed, whereas when the dye of the present invention was used, excellent characteristics were exhibited.

[Experiment 6]
A paste in which semiconductor fine particles were dispersed was prepared using titanium oxides having different particle sizes. Using this, a photoelectrochemical cell was produced and its characteristics were evaluated.

[Preparation of paste]
(Paste 1)
A titania slurry was prepared by placing spherical TiO ₂ particles (anatase type, average particle size: 25 nm, hereinafter referred to as spherical TiO ₂ particles 1) in a nitric acid solution and stirring. Next, a cellulose binder as a thickener was added to the titania slurry and kneaded to prepare a paste.

(Paste 2)
A titania slurry was prepared by placing spherical TiO ₂ particles 1 and spherical TiO ₂ particles (anatase type, average particle size: 200 nm, hereinafter referred to as spherical TiO ₂ particles 2) in a nitric acid solution and stirring. Next, a cellulose binder as a thickener was added to the titania slurry and kneaded to prepare a paste (mass of TiO ₂ particles 1: mass of TiO ₂ particles 2 = 30:70).

(Paste 3)
The paste 1 is mixed with rod-like TiO ₂ particles (anatase type, diameter: 100 nm, aspect ratio: 5, hereinafter referred to as rod-like TiO ₂ particles 1), the mass of the rod-like TiO ₂ particles 1: the mass of the paste 1 = 10: Ninety pastes were prepared.

(Paste 4)
The paste 1, a rod-shaped TiO ₂ particles 1 were mixed, the mass rod-shaped TiO ₂ particles 1: Paste 1 Mass = 30: 70 paste was prepared.

(Paste 5)
The paste 1, a rod-shaped TiO ₂ particles 1 were mixed, the mass rod-shaped TiO ₂ particles 1: Paste 1 Mass = 50: 50 paste was prepared.

(Paste 6)
The paste 1 is mixed with plate-like mica particles (diameter: 100 nm, aspect ratio: 6, hereinafter referred to as plate-like mica particles 1), and the mass of the plate-like mica particles 1: the mass of the paste 1 = 20: 80 paste. Was prepared.

(Paste 7)
The paste 1 is mixed with rod-like TiO ₂ particles (anatase, diameter: 30 nm, aspect ratio: 6.3, hereinafter referred to as rod-like TiO ₂ particles 2), the mass of the rod-like TiO ₂ particles 2: the mass of the paste 1 = 30: 70 pastes were prepared.

(Paste 8)
The paste 1 is mixed with rod-like TiO ₂ particles (anatase, diameter: 50 nm, aspect ratio: 6.1, hereinafter referred to as rod-like TiO ₂ particles 3), and the mass of the rod-like TiO ₂ particles 3: the mass of the paste 1 = 30. : 70 paste was prepared.

(Paste 9)
The paste 1 is mixed with rod-like TiO ₂ particles (anatase, diameter: 75 nm, aspect ratio: 5.8, hereinafter referred to as rod-like TiO ₂ particles 4), and the mass of the rod-like TiO ₂ particles 4: the mass of the paste 1 = 30. : 70 paste was prepared.

(Paste 10)
The paste 1 is mixed with rod-like TiO ₂ particles (anatase, diameter: 130 nm, aspect ratio: 5.2, hereinafter referred to as rod-like TiO ₂ particles 5), and the mass of the rod-like TiO ₂ particles 5: the mass of the paste 1 = 30. : 70 paste was prepared.

(Paste 11)
The paste 1 is mixed with rod-like TiO ₂ particles (anatase, diameter: 180 nm, aspect ratio: 5, hereinafter referred to as rod-like TiO ₂ particles 6), and the mass of the rod-like TiO ₂ particles 6: the mass of the paste 1 = 30: 70. A paste was prepared.

(Paste 12)
The paste 1 is mixed with rod-like TiO ₂ particles (anatase, diameter: 240 nm, aspect ratio: 5, hereinafter referred to as rod-like TiO ₂ particles 7), and the mass of the rod-like TiO ₂ particles 7: the mass of the paste 1 = 30: 70. A paste was prepared.

(Paste 13)
The paste 1 is mixed with rod-like TiO ₂ particles (anatase, diameter: 110 nm, aspect ratio: 4.1, hereinafter referred to as rod-like TiO ₂ particles 8), and the mass of the rod-like TiO ₂ particles 8: the mass of the paste 1 = 30. : 70 paste was prepared.

(Paste 14)
The paste 1 is mixed with rod-shaped TiO ₂ particles (anatase, diameter: 105 nm, aspect ratio: 3.4, hereinafter referred to as rod-shaped TiO ₂ particles 9), and the mass of the rod-shaped TiO ₂ particles 9: the mass of the paste 1 = 30. : 70 paste was prepared.

(Photoelectrochemical cell 1)
A photoelectrode having the same configuration as the photoelectrode 12 shown in FIG. 5 of JP-A-2002-289274 is prepared by the following procedure, and further, using the photoelectrode, dye sensitization other than the photoelectrode is performed. A 10 × 10 mm scale photoelectrochemical cell 1 having the same configuration as the solar cell 20 was produced.

A transparent electrode in which a fluorine-doped SnO ₂ conductive film (film thickness: 500 nm) was formed on a glass substrate was prepared.
On the SnO ₂ conductive film, the paste 2 was screen-printed and then dried. Then, it baked on the conditions of 450 degreeC in the air. Further, by repeating the firing and the screen printing using a paste 4, the semiconductor electrodes (area of the light receiving surface of the same structure as the semiconductor electrode 2 shown in FIG. 5 of Patent Document on SnO ₂ conductive film; 10 mm × 10 mm, layer thickness: 10 μm, semiconductor layer thickness: 6 μm, light scattering layer thickness: 4 μm, content of rod-like TiO ₂ particles 1 contained in the light scattering layer; 30% by mass) for sensitization A photoelectrode containing no dye was prepared.

Next, the pigment | dye was made to adsorb | suck to a semiconductor electrode as follows. First, an absolute ethanol dehydrated with magnesium ethoxide was used as a solvent, and each of the dyes described in Table 6 was dissolved so as to have a concentration of 3 × 10 ⁻⁴ mol / L to prepare a dye solution. Next, the semiconductor electrode was immersed in this solution, whereby about 1.5 × 10 ⁻⁷ mol / cm ² of the dye was adsorbed to the semiconductor electrode in total, and the photoelectrode 10 was completed.

  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 spacer S (trade name: “Surlin”) manufactured by DuPont having a shape corresponding to the size of the semiconductor electrode is prepared. As shown in FIG. 3 of JP-A-2002-289274, the photoelectrode 10 and The counter electrode CE and the spacer S were opposed to each other, and the above electrolyte was filled therein to complete the photoelectrochemical cell 1.

(Photoelectrochemical cell 2)
The photoelectrode 10 shown in FIG. 1 described in JP-A-2002-289274 was prepared by the same procedure as that of the photoelectrochemical cell 1 except that the semiconductor electrode was manufactured as follows. A photoelectrochemical cell 2 having the same configuration as that of the dye-sensitized solar cell 20 shown in FIG.

Paste 2 was used as a semiconductor layer forming paste. Then, paste 2 was screen-printed on the SnO ₂ conductive film and then dried. Then, it baked on the conditions of 450 degreeC in the air, and formed the semiconductor layer.

  Paste 3 was used as the innermost layer forming paste of the light scattering layer. The paste 5 was used as the outermost layer forming paste of the light scattering layer. Then, a light scattering layer was formed on the semiconductor layer in the same manner as in the photoelectrochemical cell 1.

Then, on the SnO ₂ conductive film, a semiconductor electrode having the same structure as the semiconductor electrode 2 shown in FIG. 1 described in JP-A-2002-289274 (area of light receiving surface; 10 mm × 10 mm, layer thickness: 10 μm, semiconductor layer) Layer thickness: 3 μm, innermost layer thickness: 4 μm, content of rod-like TiO ₂ particles 1 contained in the innermost layer; 10 mass%, outermost layer thickness: 3 μm, innermost layer The content ratio of the rod-like TiO ₂ particles 1 contained in 1; 50% by mass) was formed, and a photoelectrode containing no sensitizing dye was produced. Similarly to the photoelectrochemical cell 1, the photoelectrochemical cell 2 was completed by making the photoelectrode, the counter electrode CE, and the spacer S face each other and filling the above electrolyte therein.

(Photoelectrochemical cell 3)
According to the same procedure as that of the photoelectrochemical cell 1, except that the paste 1 was used as a semiconductor layer forming paste and the paste 4 was used as a light scattering layer forming paste in the production of a semiconductor electrode. 5 was produced, and a photoelectrochemical cell 3 having the same configuration as the photoelectrochemical cell 20 shown in FIG. 3 described in JP-A-2002-289274 was produced.
The semiconductor electrode has a light receiving surface area of 10 mm × 10 mm, a layer thickness of 10 μm, a semiconductor layer thickness of 5 μm, a light scattering layer thickness of 5 μm, and the rod-like TiO ₂ particles 1 contained in the light scattering layer. Content rate: 30% by mass.

(Photoelectrochemical cell 4)
In the production of the semiconductor electrode, the light shown in FIG. 5 was obtained by the same procedure as that of the photoelectrochemical cell 1 except that the paste 2 was used as the semiconductor layer forming paste and the paste 6 was used as the light scattering layer forming paste. A photoelectrode and a photoelectrochemical cell 4 having the same configuration as the electrode 10 and the photoelectrochemical cell 20 shown in FIG. 3 described in JP-A-2002-289274 were produced. The semiconductor electrode has a light receiving surface area: 10 mm × 10 mm, layer thickness: 10 μm, semiconductor layer thickness: 6.5 μm, light scattering layer thickness: 3.5 μm, plate-like contained in the light scattering layer The content of mica particles 1 was 20% by mass.

(Photoelectrochemical cell 5)
In the production of the semiconductor electrode, the photoelectrochemical cell 5 was prepared by the same procedure as that of the photoelectrochemical cell 1 except that the paste 2 was used as the semiconductor layer forming paste and the paste 8 was used as the light scattering layer forming paste. Produced. The content ratio of the rod-shaped TiO ₂ particles 3 contained in the light scattering layer of the semiconductor electrode; was 30 wt%.

(Photoelectrochemical cell 6)
In the production of the semiconductor electrode, the photoelectrochemical cell 6 was prepared by the same procedure as that of the photoelectrochemical cell 1 except that the paste 2 was used as the semiconductor layer forming paste and the paste 9 was used as the light scattering layer forming paste. Produced. The content ratio of the rod-shaped TiO ₂ particles 4 contained in the light scattering layer of the semiconductor electrode; was 30 wt%.

(Photoelectrochemical cell 7)
In the production of the semiconductor electrode, the photoelectrochemical cell 7 was prepared by the same procedure as that of the photoelectrochemical cell 1 except that the paste 2 was used as the semiconductor layer forming paste and the paste 10 was used as the light scattering layer forming paste. Produced. The content ratio of the rod-shaped TiO ₂ particles 5 contained in the light scattering layer of the semiconductor electrode; was 30 wt%.

(Photoelectrochemical cell 8)
In the production of the semiconductor electrode, the photoelectrochemical cell 8 was prepared by the same procedure as the photoelectrochemical cell 1 except that the paste 2 was used as the semiconductor layer forming paste and the paste 11 was used as the light scattering layer forming paste. Produced. The content ratio of the rod-shaped TiO ₂ particles 6 contained in the light scattering layer of the semiconductor electrode; was 30 wt%.

(Photoelectrochemical cell 9)
In the production of the semiconductor electrode, the photoelectrochemical cell 9 was prepared in the same procedure as the photoelectrochemical cell 1 except that the paste 2 was used as the semiconductor layer forming paste and the paste 13 was used as the light scattering layer forming paste. Produced. The content ratio of the rod-shaped TiO ₂ particles 8 contained in the light scattering layer of the semiconductor electrode; was 30 wt%.

(Photoelectrochemical cell 10)
In the production of the semiconductor electrode, the photoelectrochemical cell 10 was prepared by the same procedure as that of the photoelectrochemical cell 1 except that the paste 2 was used as the semiconductor layer forming paste and the paste 14 was used as the light scattering layer forming paste. Produced. The content of the rod-like TiO ₂ particles 9 contained in the light scattering layer of the semiconductor electrode was 30% by mass.

(Photoelectrochemical cell 11)
Similar to the photoelectrochemical cell 1 except that a semiconductor electrode (light-receiving surface area: 10 mm × 10 mm, layer thickness: 10 μm) made of only the semiconductor layer using only the paste 2 was manufactured in the manufacture of the semiconductor electrode. The photoelectrochemical cell 11 was produced according to the procedure.

(Electrochemical battery 12)
In the production of the semiconductor electrode, the photoelectrode and the comparative photoelectricity were prepared in the same procedure as in the photoelectrochemical cell 1 except that the paste 2 was used as the semiconductor layer forming paste and the paste 7 was used as the light scattering layer forming paste. A chemical battery 12 was produced. The content ratio of the rod-shaped TiO ₂ particles 2 contained in the light scattering layer of the semiconductor electrode; was 30 wt%.

[Testing and evaluation of characteristics]
About the photoelectrochemical cells 1-12, 1000 W / m < ² > pseudo-sunlight was irradiated from the xenon lamp which passed the AM1.5 filter using the solar simulator (the product made from WACOM, WXS-85H (brand name)). Current-voltage characteristics were measured using an IV tester to determine an initial value of conversion efficiency. The results are shown in Table 6.
Conversion efficiency of 2.5% or more is indicated as ◎, 1% or more and less than 2.5% is indicated as ◯, 0.3% or more and less than 1% is indicated as △, and less than 0.3% is indicated as ×. The conversion efficiency of 0.3% or more was accepted and the conversion efficiency of less than 0.3% was rejected. Further, the conversion efficiency after 500 hours with respect to the initial value of conversion efficiency is 90% or more, ◎, 60% or more and less than 90%, ◯, 40% or more and less than 60%, or less than 40%. Things were evaluated as x and the results are shown in Table 6. When the conversion efficiency after 500 hours was 60% or more with respect to the initial value of the conversion efficiency, it was determined to be acceptable, and when the conversion efficiency was less than 60%, it was rejected.

As can be seen from Table 6, in the photoelectrochemical cell using the dye of the present invention, the initial value of the conversion efficiency is 1% or more, and the conversion efficiency after 500 hours is excellent, being 60% or more of the initial value. Showed high durability.
On the other hand, when the comparative dye was used, it was found that the initial value of the conversion efficiency was an acceptable level, but there was a problem with durability.

[Experiment 7]
A slurry obtained by adding metal alkoxide to metal oxide fine particles was applied to a conductive substrate, and then UV ozone irradiation, UV irradiation or drying was performed to produce an electrode. Then, the photoelectrochemical cell was produced and the conversion efficiency was measured.

(Metal oxide fine particles)
Titanium oxide was used as the metal oxide fine particles. As the titanium oxide, P25 powder (trade name, manufactured by Degussa) having a mass ratio of 30% rutile type and 70% anatase type and an average particle size of 25 nm was used.

(Pretreatment of metal oxide fine particle powder)
The metal oxide fine particles were previously heat-treated to remove surface organic substances and moisture. In the case of titanium oxide fine particles, the fine particles were heated in an oven at 450 ° C. in the atmosphere for 30 minutes.

(Measurement of water content in metal oxide fine particles)
When the moisture content contained in titanium oxide and P25 powder (trade name, manufactured by Degussa) stored in an environment of temperature 26 ° C. and humidity 72% is reduced by thermogravimetry and heated to 300 ° C. The amount of moisture desorbed was determined by Karl Fischer titration.

  When the amount of water desorbed when titanium oxide, P25 powder (trade name, manufactured by Degussa) was heated at 300 ° C. was quantified by Karl Fischer titration, 0.253 mg of water was contained in 0.1033 g of titanium oxide fine powder. It was included. That is, the fine titanium oxide powder contained about 2.5% by mass of water. It was heat-treated for 30 minutes, cooled and stored in a desiccator.

(Preparation of metal alkoxide paste)
The metal alkoxide that plays a role in bonding metal oxide fine particles includes titanium (IV) tetraisopropoxide (TTIP) as a titanium raw material, zirconium (IV) tetra n-propoxide as a zirconium raw material, and niobium as a niobium raw material. (V) Pentaethoxide (all manufactured by Aldrich) was used.

  The molar concentration ratio between the metal oxide fine particles and the metal alkoxide is appropriately adjusted according to the metal oxide fine particle diameter so that the amorphous layer generated by hydrolysis of the metal alkoxide is not excessively thick and the particles can be sufficiently bonded to each other. did. All metal alkoxides were 0.1M ethanol solutions. When mixing titanium oxide fine particles and titanium (IV) tetraisopropoxide (TTIP), 3.55 g of 0.1M TTIP solution was mixed with 1 g of titanium oxide fine particles. At this time, the titanium oxide concentration in the obtained paste was about 22% by mass, and the viscosity was appropriate for coating. Moreover, the titanium oxide, TTIP, and ethanol at this time were 1: 0.127: 3.42 by mass ratio, and 1: 0.036: 5.92 by molar ratio.

  Similarly, a mixed paste of titanium oxide fine particles and an alkoxide other than TTIP was prepared so that the fine particle concentration was 22% by mass. In the paste using zinc oxide and tin oxide fine particles, the content was 16% by mass. In the case of zinc oxide and tin oxide, the metal alkoxide solution was mixed at a ratio of 5.25 g to 1 g of the metal oxide fine particles.

  The metal oxide fine particles and the metal alkoxide solution were stirred for 2 hours with a magnetic stirrer in a sealed container to obtain a uniform paste. As a method for applying the paste to the conductive substrate, a doctor blade method, a screen printing method, a spray coating method, or the like can be used, and an appropriate paste viscosity is appropriately selected depending on the application method. Here, a method of applying simply with a glass rod (similar to the doctor blade method) was used. In this case, the concentration of the metal oxide fine particles giving an appropriate paste viscosity was approximately in the range of 5 to 30% by mass.

  In this experiment, the thickness of the amorphous metal oxide produced by the decomposition of the metal alkoxide was in the range of about 0.1 to 0.6 nm, and the thickness could be set to an appropriate range.

(Applying paste on conductive substrate and air-drying treatment)
Two adhesive tapes as spacers on a polyethylene terephthalate (PET) film substrate (20Ω / cm ² ) with tin-doped indium oxide (ITO) conductive film or a glass substrate (10Ω / cm ² ) with fluorine-doped tin oxide (FTO) conductive film The pastes were applied in parallel at regular intervals, and each paste prepared according to the above method was uniformly applied using a glass rod.
After applying the paste and before dye adsorption, a porous film was prepared by changing the conditions for the presence or absence of UV ozone treatment, UV irradiation treatment, or drying treatment.

(Drying process)
The film after application to the conductive substrate was air-dried in the atmosphere at room temperature for about 2 minutes. During this process, the metal alkoxide in the paste was hydrolyzed by moisture in the atmosphere, and amorphous titanium oxide, zirconium oxide, and niobium oxide were formed from Ti alkoxide, Zr alkoxide, and Nb alkoxide, respectively.
Since the produced amorphous metal oxide plays a role of adhering metal oxide fine particles and the film to the conductive substrate, a porous film excellent in mechanical strength and adhesion was obtained only by air drying.

(UV ozone treatment)
NL-UV253 UV ozone cleaner manufactured by Nippon Laser Electronics Co., Ltd. was used for UV ozone treatment. The UV light source was equipped with three 4.5 W mercury lamps having emission lines at 185 nm and 254 nm, and the sample was placed horizontally at a distance of about 6.5 cm from the light source. Ozone is generated by introducing an oxygen stream into the chamber. In this example, this UV ozone treatment was performed for 2 hours. Note that no decrease in the conductivity of the ITO film and the FTO film due to this UV ozone treatment was observed.

(UV treatment)
Similarly to the UV ozone treatment, the treatment was performed for 2 hours, except that the inside of the chamber was replaced with nitrogen. No decrease in the conductivity of the ITO film and FTO film due to the UV treatment was observed.

(Dye adsorption)
Using the dyes listed in Table 7 as the dye, a 0.5 mM ethanol solution of each dye was prepared. In this experiment, the porous film produced by the above process was dried in an oven at 100 ° C. for 1 hour, then immersed in a sensitizing dye solution, and allowed to stand at room temperature for 50 minutes to adsorb the dye on the titanium oxide surface. The sample after dye adsorption was washed with ethanol and air-dried.

(Production of photoelectrochemical cell and evaluation of battery characteristics)
A photoelectrochemical cell was fabricated by using a conductive substrate on which a porous film after dye adsorption was formed as a photoelectrode, and an ITO / PET film or FTO / glass counter electrode in which platinum fine particles were modified by sputtering. The effective area of the photoelectrode was about 0.2 cm ² . As the electrolyte solution, 3-methoxypropionitrile containing 0.5 M LiI, 0.05 M I ₂ and 0.5 M t-butylpyridine was introduced into the gap between the two electrodes by capillary action.

The battery performance was evaluated by photocurrent action spectrum measurement under irradiation with a constant number of photons (1016 cm ⁻² ) and IV measurement under irradiation with AM1.5 simulated sunlight (100 mW / cm ² ). A CEP-2000 type spectral sensitivity measuring device manufactured by Spectrometer Co., Ltd. was used for these measurements. The conversion efficiency obtained is shown in Table 7.
Conversion efficiency is 2.0% or more, ◎, 0.8% or more, less than 2.0%, ○, 0.3% or more, less than 0.8%, △, less than 0.3% Was displayed as x, and those with a conversion efficiency of 0.3% or more were accepted and those with less than 0.3% were rejected. Further, the conversion efficiency after 500 hours with respect to the initial value of conversion efficiency is 90% or more, ◎, 60% or more and less than 90%, ◯, 40% or more and less than 60%, or less than 40%. Those were evaluated as x, and the results are shown in Table 7 as durability. When the conversion efficiency after 500 hours was 60% or more with respect to the initial value of the conversion efficiency, it was determined to be acceptable, and when the conversion efficiency was less than 60%, it was rejected.

  In Table 7, the columns of “UV ozone”, “UV”, and “dry” indicate the presence / absence of UV ozone treatment, UV irradiation treatment, and drying treatment after formation of the porous film and before sensitizing dye adsorption, respectively. The processed one is “◯”, and the unprocessed one is “×”.

The column of _“ Pretreatment of TiO ₂ ” in Table 7 indicates the presence or absence of pretreatment of titanium oxide fine particles (heat treatment in an oven at 450 ° C. for 30 minutes). Samples 6, 14, and 22 represent samples using a paste having a high TTIP concentration (titanium oxide: TTIP molar ratio of 1: 0.356). All other samples (samples 1 to 5, 7 to 13, 23, and 24) were made of a paste of titanium oxide: TTIP = 1: 0.0356.

As can be seen from Table 7, the photoelectrochemical cell using the dye of the present invention, after the formation of the porous film and before the sensitizing dye adsorption, regardless of the presence or absence of UV ozone treatment, UV irradiation treatment, drying treatment, It was found that the conversion efficiency of the photoelectrochemical cell was always higher than that when the dye was used alone, and a conversion efficiency at a pass level was obtained. Furthermore, the conversion efficiency after the elapse of 500 hours was 60% or more of the initial value, indicating excellent durability.
On the other hand, when the comparative dye was used, it was found that the initial value of the conversion efficiency was an acceptable level, but there was a problem with durability.

[Experiment 8]
Using acetonitrile as a solvent, an electrolyte solution was prepared by dissolving 0.1 mol / L of lithium iodide, 0.05 mol / L of iodine, and 0.62 mol / L of dimethylpropylimidazolium iodide. No. shown below. 1-No. 8 benzimidazole compounds were separately added and dissolved so as to have a concentration of 0.5 mol / L.

No. 1-No. No. 8 benzimidazole compound electrolyte was dropped onto a porous titanium oxide semiconductor thin film (thickness: 15 μm) in which the dyes listed in Table 8 were supported on conductive glass. A frame type spacer (thickness: 25 μm) made of a polyethylene film was placed thereon, and this was covered with a platinum counter electrode to produce a photoelectric conversion element.
The obtained photoelectric conversion element was irradiated with light having an intensity of 100 mW / cm ^{2 using} a Xe lamp as a light source. Table 8 shows the open circuit voltage and photoelectric conversion efficiency obtained.

(Evaluation of results)
(I) The open circuit voltage is 7.0 V or more, ◎, 6.5 V or more and less than 7.0 V, ◯, 6.0 V or more and less than 6.5 V, Δ, or less than 6.0 V × It was displayed as 6.5V or more as the pass.
(Ii) A conversion efficiency of 2.0% or more is ◎, 0.8% or more and less than 2.0% ○, 0.3% or more and less than 0.8% Δ, 0.3% Those with a conversion efficiency of 0.3% or higher were accepted and those with less than 0.3% were rejected. Further, the conversion efficiency after 500 hours with respect to the initial value of conversion efficiency is 90% or more, ◎, 60% or more and less than 90%, ◯, 40% or more and less than 60%, or less than 40%. Those were evaluated as x, and the results are shown in Table 8 as durability. When the conversion efficiency after 500 hours was 60% or more with respect to the initial value of the conversion efficiency, it was determined to be acceptable, and when the conversion efficiency was less than 60%, it was rejected.
Table 8 also shows the results of photoelectric conversion elements using an electrolytic solution to which no benzimidazole compound was added.

As can be seen from Table 8, in the photoelectrochemical cell using the dye of the present invention, the initial values of the open circuit voltage and the conversion efficiency are both acceptable levels, and the conversion efficiency after the elapse of 500 hours is 60% or more of the initial value. And showed excellent durability.
On the other hand, when the comparative dye was used, the initial values of the open circuit voltage and the conversion efficiency were acceptable levels, but it was found that there was a problem in durability.

[Experiment 9]
(Photoelectrochemical cell 1)
According to the following procedure, a photoelectrode having the same configuration as the photoelectrode 10 shown in FIG. 1 of JP-A No. 2004-152613 (however, the semiconductor electrode 2 has a two-layer structure) is manufactured. Except for using this photoelectrode, a photoelectrochemical cell having the same structure as the dye-sensitized solar cell 20 shown in FIG. 1 of JP-A No. 2004-152613 (the area of the light receiving surface F2 of the semiconductor electrode 2 is 1 cm). ² ) was produced. For each layer of the semiconductor electrode 2 having the two-layer structure, a layer disposed on the side close to the transparent electrode 1 is referred to as “first layer”, and a layer disposed on the side close to the porous body layer PS is referred to as “second layer”. The layer.

First, P25 powder having an average particle diameter of 25 nm (trade name, manufactured by Degussa), titanium oxide particles having a different particle diameter, and P200 powder (average particle diameter: 200 nm, product name, manufactured by Degussa) were used. And P200 are 15% by mass, and the mass ratio of P25 and P200 is P25: P200 = 30: 70, so that acetylacetone, ion-exchanged water, surfactant (manufactured by Tokyo Chemical Industry Co., Ltd.) , Trade name: “Triton-X”) and kneaded to prepare a slurry for forming a second layer (hereinafter referred to as “slurry 1”).
Next, the slurry for forming the first layer (P1 content: 15 mass%; hereinafter, “slurry” was prepared by the same preparation procedure as that of the slurry 1 except that only P25 was used without using P200. 2)) was prepared.

On the other hand, a transparent electrode (thickness: 1.1 mm) in which a fluorine-doped SnO ₂ conductive film (film thickness: 700 nm) was formed on a glass substrate (transparent conductive glass) was prepared. Then, the SnO ₂ conductive film, the slurry 2 described above was coated with Bakoda, then dried. Then, it baked for 30 minutes at 450 degreeC in air | atmosphere. In this way, the first layer of the semiconductor electrode 2 was formed on the transparent electrode.

Furthermore, the second layer was formed on the first layer by repeating the same application and firing as described above using the slurry 1. In this way, the semiconductor electrode 2 (light-receiving surface area; 1.0 cm ² , the total thickness of the first layer and the second layer: 10 μm (the thickness of the first layer: 3 μm, the first layer) on the SnO ₂ conductive film No. 2 layer thickness: 7 μm)), and a photoelectrode 10 containing no sensitizing dye was prepared.

Next, an ethanol solution of the dye described in Table 9 (concentration of each sensitizing dye; 3 × 10 ⁻⁴ mol / L) was prepared as the dye. The photoelectrode 10 was immersed in this solution and allowed to stand for 20 hours under a temperature condition of 80 ° C. As a result, a total of about 1.0 × 10 ⁻⁷ mol / cm ^{2 of} sensitizing dye was adsorbed inside the semiconductor electrode.

  Next, a counter electrode CE having the same shape and size as the above photoelectrode was produced. First, an isopropanol solution of chloroplatinic acid hexahydrate was dropped on a transparent conductive glass, dried in air, and then baked at 450 ° C. for 30 minutes to obtain a platinum sintered counter electrode CE. The counter electrode CE was previously provided with a hole for injection of the electrolyte E (diameter 1 mm).

  Next, zinc iodide, 1,2-dimethyl-3-propylimidazolium iodide, iodine, and 4-tert-butylpyridine are dissolved in methoxyacetonitrile as a solvent to form a liquid electrolyte (iodide). Zinc concentration: 10 mmol / L, dimethylpropylimidazolium iodide concentration: 0.6 mol / L, iodine concentration: 0.05 mol / L, 4-tert-butylpyridine concentration: 1 mol / L).

Next, a spacer S (trade name: “HIMILAN”, ethylene / methacrylic acid random copolymer ionomer film) manufactured by Mitsui Dupont Polychemical Co., Ltd. having a shape matched to the size of the semiconductor electrode was prepared. As shown in FIG. 1 of Japanese Patent No. 152613, the photoelectrode and the counter electrode were opposed to each other via a spacer, and each was bonded by thermal welding to obtain a battery casing (no electrolyte filled).
Next, after injecting the liquid electrolyte into the housing from the hole of the counter electrode, the hole is closed with a member made of the same material as the spacer, and this member is thermally welded to the hole of the counter electrode to seal the hole. 1 was completed.

(Photoelectrochemical cell 2)
The photoelectrochemical cell 2 was produced in the same procedure and conditions as the photoelectrochemical cell 1 except that the concentration of zinc iodide in the liquid electrolyte was 50 mmol / L.

(Photoelectrochemical cell 3)
Comparative photoelectrochemistry was performed in the same procedure and conditions as in the photoelectrochemical cell 1 except that lithium iodide was added instead of zinc iodide in the liquid electrolyte, and the concentration of lithium iodide in the liquid electrolyte was 20 mmol / L. Battery 1 was produced.

(Comparative electrochemical cell 4)
Comparative photoelectrochemistry in the same procedure and conditions as in the photoelectrochemical cell 1 except that lithium iodide was added instead of zinc iodide in the liquid electrolyte, and the concentration of lithium iodide in the liquid electrolyte was 100 mmol / L. Battery 4 was produced.

(Examination and evaluation)
Conversion efficiency was measured about the sample using the photoelectrochemical cells 1-4 by the following procedures.
The battery characteristic evaluation test uses a solar simulator (trade name; “WXS-85-H type”, manufactured by Wacom), and the irradiation conditions of pseudo-sunlight from a xenon lamp light source through an AM filter (AM1.5), The measurement was performed under measurement conditions of 100 mW / cm ² (so-called “1Sun” irradiation conditions).

About each photoelectrochemical cell, the current-voltage characteristic was measured at room temperature using the IV tester, and conversion efficiency was calculated | required from these. The obtained results are shown as “initial values” in Table 9A (1 Sun irradiation conditions). Further, Table 9A also shows the results of conversion efficiency after 300 hours of conversion efficiency under operating conditions of 60 ° C., 1 Sun irradiation and 10Ω load. An initial value of conversion efficiency of 2.4% or more was accepted and less than 2.4% was rejected. Moreover, the rate of decrease in conversion efficiency after the elapse of 300 hours passed 20% or less with respect to the initial value, and the rate exceeding 20% was rejected.
Moreover, it evaluated similarly except having measured the result of the conversion efficiency after 500 hours progress of conversion efficiency. The results are shown in Table 9B.

As can be seen from Tables 9A and 9B, in the photoelectrochemical cell using the dye of the present invention, both the initial values of the conversion efficiency are acceptable levels, and the reduction rate of the conversion efficiency after 300 hours is 20% or less. Showed excellent durability.
On the other hand, when the comparative dye was used, it was found that the initial value of the conversion efficiency was an acceptable level, but there was a problem with durability.

[Experiment 10]
1. Preparation of Titanium Dioxide Dispersion 15 g of titanium dioxide fine particles (Nippon Aerosil Co., Ltd., Degussa P-25), water 45 g, dispersant (Aldrich, Triron X −100) 1 g and 30 g of zirconia beads having a diameter of 0.5 mm (manufactured by Nikkato Co., Ltd.) were added, and dispersion treatment was performed at 1500 rpm for 2 hours using a sand grinder mill (manufactured by Imex). Zirconia beads were filtered off from the resulting dispersion. The average particle diameter of the titanium dioxide fine particles in the obtained dispersion was 2.5 μm. The particle size was measured with a master sizer (trade name) manufactured by MALVERN.

2. Preparation of Titanium Oxide Fine Particle Layer (Electrode A) Adsorbed with Dye 20 mm × 20 mm conductive glass plate coated with fluorine-doped tin oxide (Asahi Glass Co., Ltd., TCO glass-U, surface resistance: about 30Ω / m ² ) was prepared, and an adhesive tape for spacers was applied to both ends (a portion having a width of 3 mm from the end) on the conductive layer side, and then the dispersion was applied onto the conductive layer using a glass rod. After application of the dispersion, the adhesive tape was peeled off and air-dried at room temperature for 1 day. Next, this semiconductor-coated glass plate was placed in an electric furnace (muffle furnace FP-32 type manufactured by Yamato Scientific Co., Ltd.) and baked at 450 ° C. for 30 minutes. The semiconductor-coated glass plate was taken out and cooled, and then immersed in an ethanol solution of the dyes shown in Table 10 (concentration: 3 × 10 ⁻⁴ mol / L) for 3 hours. The semiconductor-coated glass plate on which the dye was adsorbed was immersed in 4-tert-butylpyridine for 15 minutes, then washed with ethanol and naturally dried to obtain a titanium oxide fine particle layer (electrode A) on which the dye was adsorbed. The thickness of the dye-sensitized titanium oxide fine particle layer of the electrode A was 10 μm, and the coating amount of the titanium oxide fine particles was 20 g / m ² . Moreover, the adsorption amount of the pigment | dye was in the range of 0.1-10 mmol / m < ² > according to the kind.

3. Production of Photoelectrochemical Battery a As a solvent, a mixture of acetonitrile and 3-methyl-2-oxazolidinone in a volume ratio of 90/10 was used. To this solvent, iodine and 1-methyl-3-hexylimidazolium iodine salt were added as an electrolyte salt to prepare a solution containing 0.5 mol / L electrolyte salt and 0.05 mol / L iodine. To this solution, 10 parts by mass of the nitrogen-containing polymer compound (α) was added to 100 parts by mass of (solvent + nitrogen-containing polymer compound + salt). Furthermore, 0.1 mol of an electrophile (β) for the reactive nitrogen atom of the nitrogen-containing polymer compound was mixed to obtain a uniform reaction solution.

On the other hand, on the dye-sensitized titanium oxide fine particle layer of electrode A, a platinum thin film side of a counter electrode made of a glass plate on which platinum is vapor-deposited through a spacer is placed, and the conductive glass plate and the platinum vapor-deposited glass plate are fixed. did. The open end of the obtained assembly was immersed in the electrolyte solution, and the reaction solution was infiltrated into the dye-sensitized titanium oxide fine particle layer by capillary action.
Subsequently, it heated at 80 degreeC for 30 minutes, and the crosslinking reaction was performed. Thus, as shown in FIG. 2 of JP 2000-323190 A, the dye-sensitized titanium oxide fine particle layer 20, the electrolyte layer 30, the platinum thin film 42, and the glass are formed on the conductive layer 12 of the conductive glass plate 10. A photoelectrochemical cell a-1 (sample number 10-1) of the present invention in which the counter electrode 40 composed of the plate 41 was sequentially laminated was obtained.
Further, by repeating the above steps except that the combination of the composition of the dye and the electrolyte composition was changed as shown in Table 10, a photoelectrochemical cell a-2 having a different photoconductor and / or charge transfer body (sample number 10- 4) was obtained.

4). Production of photoelectrochemical cells b and c (1) Photoelectrochemical cell b
An electrode A (20 mm × 20 mm) composed of a titanium oxide fine particle layer dye-sensitized with the dye of the present invention as described above was superimposed on a platinum-deposited glass plate of the same size via a spacer. Next, using a capillary phenomenon in the gap between both glass plates, an electrolytic solution (0.05 mol / L of iodine using a mixture of acetonitrile and 3-methyl-2-oxazolidinone in a volume ratio of 90/10 as a solvent, lithium iodide 0) .5 mol / L solution) was infiltrated to produce photoelectrochemical cell b-1. Moreover, the photoelectrochemical cell b-2 (sample number 10-5) was obtained by repeating the said process except having changed the pigment | dye as shown in Table 10.

(2) Photoelectrochemical cell c (electrolyte described in JP-A-9-27352)
The electrolytic solution was applied and impregnated on the electrode A (20 mm × 20 mm) composed of the titanium oxide fine particle layer dye-sensitized with the dye of the present invention as described above. The electrolyte was 1 g of hexaethylene glycol methacrylate (manufactured by Nippon Oil & Fats Chemical Co., Ltd., Bremer PE-350), 1 g of ethylene glycol, and 2-hydroxy-2-methyl-1-phenyl-propane as a polymerization initiator. It was obtained by dissolving 500 mg of lithium iodide in a mixed solution containing 20 mg of -1-one (manufactured by Ciba Geigy Japan, Darocur 1173) and vacuum degassing for 10 minutes. Next, the porous titanium oxide layer impregnated with the mixed solution is placed under a reduced pressure to remove bubbles in the porous titanium oxide layer, promote penetration of the monomer, and then polymerize by irradiation with ultraviolet light. A uniform gel of the compound was filled into the fine pores of the porous titanium oxide layer. The product thus obtained was exposed to an iodine atmosphere for 30 minutes to diffuse iodine in the polymer compound, and then a platinum-deposited glass plate was superposed to obtain a photoelectrochemical cell c-1. Moreover, the photoelectrochemical cell c-2 (sample number 10-6) was obtained by repeating the said process except having changed the pigment | dye as shown in Table 10.

5. Measurement of photoelectric conversion efficiency Simulated sun which does not contain ultraviolet rays by passing light of 500W xenon lamp (made by USHIO INC.) Through AM1.5 filter (made by Oriel) and sharp cut filter (Kenko L-42) It was light. The light intensity was 89 mW / cm ² .

  Alligator clips were connected to the conductive glass plate 10 and the platinum-deposited glass plate 40 of the photoelectrochemical cell described above, and each alligator clip was connected to a current-voltage measuring device (Keutley SMU238 type (trade name)). This was irradiated with simulated sunlight from the conductive glass plate 10 side, and the generated electricity was measured with a current-voltage measuring device. Table 10 shows the initial value of the conversion efficiency of the photoelectrochemical cell determined in this way and the rate of decrease in conversion efficiency after 300 hours of continuous irradiation. An initial value of conversion efficiency of 2.7% or more was accepted and less than 2.7% was rejected. Moreover, the case where the reduction rate of the conversion efficiency after 300 hours passed was 20% or less was determined to be acceptable, and the case where it exceeded 20% was regarded as unacceptable.

（備考）
（１）色素の記号は本文中に記載の通りである。
（２）窒素含有高分子α、求電子剤βは以下の化合物を示す。

(Remarks)
(1) Symbols of pigments are as described in the text.
(2) Nitrogen-containing polymer α and electrophile β represent the following compounds.

As can be seen from Table 10, in the photoelectrochemical cell using the dye of the present invention, the initial value of the conversion efficiency is an acceptable level, and the reduction rate of the conversion efficiency after 300 hours is excellent at 15% or less. Shows durability.
On the other hand, when the comparative dye was used, it was found that the initial value of the conversion efficiency was an acceptable level, but there was a problem with durability.

DESCRIPTION OF SYMBOLS 1 Conductive support body 2 Photoconductor layer 21 Dye 22 Semiconductor fine particle 3 Charge transfer body layer 4 Counter electrode 5 Photosensitive electrode 6 Circuit 10 Photoelectric conversion element 100 Photoelectrochemical cell

Claims (16)

A dye represented by the following general formula (1), a photoelectric conversion element having a photoconductive layer and a semiconductor particle, the pigment, the following X ¹ and X ² in the ^molecule, or below P ¹ and P ² parts, a photoelectric conversion element characterized and Turkey that having an alkyl group having 5 to 18 carbon atoms.

[In the general formula (1), Q may have a fluorine atom or a chlorine atom, and display the tetravalent benzene ring, X ¹ and X ² each independently represent a sulfur atom, SansoHara child or CR ¹ R ² is represented. Wherein ^R 1, ^{R 2} is to display the alkyl group independently. R and R 'to display the alkyl group independently. P ¹ and P ² each independently represent a group represented by the following general formula (2) or (3) . W ¹ represents a counter ion as necessary to neutralize the charge. ]

[In General Formulas (2) and (3), V ¹ is a carboxy group, a fluorine atom, an alkyl group, an alkenyl group, an alkynyl group, an aromatic group, a heterocyclic group bonded by a carbon atom, or two V ¹ are bonded to each other. Represents a group that forms a benzene ring. n represents an integer of 0 to 2. When n is 2, V ¹ may be the same or different.
Y represents S, NR ⁹ , or CR ¹⁰ R ¹¹ . R ⁹ represents an alkyl group. R ¹⁰ and R ¹¹ represent an alkyl group and may be the same or different.
Z represents an alkyl group which may be substituted by a carboxy group, a 4-carboxyphenyl group or a 3,4-dicarboxyphenyl group.
R ^{3 to} R ⁶ and R ⁸ each independently represents a hydrogen atom or an alkyl group.
R ⁷ represents an oxygen atom or a group represented by any one of the following general formulas (10) to (13). ]

[In General Formulas (10) to (13), Rf represents a hydrogen atom or an alkyl group. ]

However, when the alkyl group having 5 to 18 carbon atoms has the alkyl group in X ¹ and X ² , X ¹ and X ² are CR ¹ R ² , and R ¹ and R ² are 5 carbon atoms. In the case where the P ¹ and P ² moieties have the alkyl group having 5 to 18 carbon atoms, Y is CR ¹⁰ R ¹¹ , and R ¹⁰ and R ¹¹ are 5 to 18 carbon atoms. Or Z is an alkyl group having 5 to 18 carbon atoms. The photoelectric conversion element according to claim 1 , wherein the alkyl group having 5 to 18 carbon atoms is a branched alkyl group. P ¹ and P ² in the general formula (1) are each independently the following general formula (4) or the photoelectric conversion element according to claim 1 or 2, characterized by being represented by (5) .

[In the general formula (4) and (5), V ¹ is a carboxy group, a fluorine atom, an alkyl group, an alkenyl group, an alkynyl group, an aromatic group, a heterocyclic group, or two V ¹ having a carbon atom bonded to A group that is bonded to each other to form a benzene ring is represented. n is to table an integer of 0-2. If n is 2, V ¹ may be the same or different.
Y represents S, NR ⁹ , or CR ¹⁰ R ¹¹ . R ⁹ represents an alkyl group . R ¹⁰ and R ¹¹ represent an alkyl group and may be the same or different.
Z represents an alkyl group which may be substituted by a carboxy group, a 4-carboxyphenyl group or a 3,4-dicarboxyphenyl group. ] The V ¹ is a carboxy group or an alkyl group, an alkenyl group, an alkynyl group, an aromatic group, or a heterocyclic group bonded by a carbon atom, which is substituted by a carboxy group . The photoelectric conversion element of any one . Wherein ^{V 1} is, 5 - carboxy sheet group, 5 - or a methyl group, of claims 1 to 3, wherein the two ^{V 1} is a bond to be formed with 4,5-benzene ring condensed to each other the photoelectric conversion element of any one. Claim wherein Z and V ¹ is, for a carboxy group or a carboxy group is substituted, alkyl group, alkenyl group, alkynyl group, characterized in that it is a heterocyclic group bonded with an aromatic group or a carbon atom The photoelectric conversion element of any one of 1-5 . Formula (2) is represented by the following general formula (6), the general formula (3) in any one of claims 1 to 6, characterized by being represented by the following general formula (7) The photoelectric conversion element as described.

[In one general formula (6) and ^{(7), Y, Z,} R 3 ~R 8 , the or general formula (2) (3) Y, ^Z, synonymous with R 3 to R ⁸ is there. V ¹² is to display the carboxy group. E ^{11 to} E ^{13 each} represents a hydrogen atom, a carboxy group, a fluorine atom, an alkyl group, an alkenyl group, an alkynyl group, an aromatic group, or a heterocyclic group bonded with a carbon atom. However, at least one of E ^{11 to} E ¹³ is an electron withdrawing group , and the remaining two are hydrogen atoms . p represents 2. ] Formula (2) is represented by the following general formula (8), the general formula (3) in any one of claims 1 to 3, characterized by being represented by the following general formula (9) The photoelectric conversion element as described.

[In the general formula (8) and (9), Y, ^Z, R 3 to R ^8, the or general formula (2) has the same definition Y, ^Z, and R 3 to R ⁸ (3) . L is represented by the above following formula to D, m represents 0-3 integer. When m is 2 or more, they may be different from each other. In Formula A, Xa represents NRe, O, or S. Here, Re is or a hydrogen atom an alkyl group. In formula A and formula _C, R a to R _d represents a hydrogen atom, an alkyl group or a carboxy group. In the general formula (8), p represents 2 . Rx represents a carboxy group or —CH═C (CN) (COOH) . ] Wherein Y is, S, NCH ₃ or represents a C _{(CH 3) 2,} photoelectric and Z is according to any one of claims 1 to 8, characterized in that an alkyl group having 5 to 18 carbon atoms Conversion element. Wherein ^{R 7} is, before following general formula (10) to (13) according to claim 1, characterized by being represented by any one of the photoelectric conversion element according to any one of 2, 4 and 9. Wherein ^{R 7} is represented by the following general formula (10) or claim 1, photoelectric conversion element according to any one of 2, 4 to 10, characterized by being represented by (11).

Formula (1) ^X 1, ^{X 2} each independently represent a sulfur atom, or oxygen atom represents C _{(CH 3) 2,} R and R 'are each independently alkyl Le group having 5 to 18 carbon atoms the photoelectric conversion device according to any one of claims 1 to 11, characterized in that to represent. The photoelectric conversion device according to any one of claims 1 to 12, wherein the semiconductor fine particles are titanium oxide particles. Photoelectrochemical cell characterized by comprising a photoelectric conversion device according to any one of claims 1 to 13. Represented by the following general formula (1), the following ^{X 1} and ^{X 2} in the molecule, or, below ^{P 1} and ^{P 2} moieties, dye for a photoelectric conversion device having an alkyl group having 5 to 18 carbon atoms.

[In the general formula (1), Q may have a fluorine atom or a chlorine atom, and display the tetravalent benzene ring group, X ¹ and X ² are each independently a sulfur atom, an oxygen atom or CR ¹ R ² is represented. Wherein ^R 1, ^{R 2} is to display the alkyl group independently. R and R 'to display the alkyl group independently. P ¹ and P ² each independently represent a group represented by the following general formula (2) or (3) . W ¹ represents a counter ion as necessary to neutralize the charge. ]

[In General Formulas (2) and (3), V ¹ is a carboxy group, a fluorine atom, an alkyl group, an alkenyl group, an alkynyl group, an aromatic group, a heterocyclic group bonded by a carbon atom, or two V ¹ are bonded to each other. Represents a group that forms a benzene ring. n represents an integer of 0 to 2. When n is 2, V ¹ may be the same or different.
Y represents S, NR ⁹ , or CR ¹⁰ R ¹¹ . R ⁹ represents an alkyl group. R ¹⁰ and R ¹¹ represent an alkyl group and may be the same or different.
Z represents an alkyl group which may be substituted by a carboxy group, a 4-carboxyphenyl group or a 3,4-dicarboxyphenyl group.
R ^{3 to} R ⁶ and R ⁸ each independently represents a hydrogen atom or an alkyl group.
R ⁷ represents an oxygen atom or a group represented by any one of the following general formulas (10) to (13). ]

[In General Formulas (10) to (13), Rf represents a hydrogen atom or an alkyl group. ]

However, when the alkyl group having 5 to 18 carbon atoms has the alkyl group in X ¹ and X ² , X ¹ and X ² are CR ¹ R ² , and R ¹ and R ² are 5 carbon atoms. In the case where the P ¹ and P ² moieties have the alkyl group having 5 to 18 carbon atoms, Y is CR ¹⁰ R ¹¹ , and R ¹⁰ and R ¹¹ are 5 to 18 carbon atoms. Or Z is an alkyl group having 5 to 18 carbon atoms. The pigment | dye solution for photoelectric conversion elements characterized by containing and melt | dissolving the pigment | dye for photoelectric conversion elements of Claim 15 in the organic solvent.

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