JP5061286B2 - Sensitizing dye used for dye-sensitized photoelectric conversion element and solar cell using the sensitizing dye - Google Patents

Description

  The present invention relates to a sensitizing dye used for a dye-sensitized photoelectric conversion element, a photoelectric conversion element using the sensitizing dye, and a solar cell.

  2. Description of the Related Art Conventionally, solar cells using a photoelectric conversion element that converts light energy such as sunlight into electrical energy have been widely used as a power generation method that is environmentally friendly and does not cause resource depletion. As such a solar cell, those using a silicon single crystal, amorphous silicon, or the like are conventionally known, but in recent years, a dye-sensitized solar cell that can be manufactured at a lower cost than the silicon solar cell. Is getting attention.

  Such photoelectric conversion elements used for solar cells are required to have excellent photoelectric conversion characteristics. For these reasons, a photoelectric conversion element for a dye-sensitized solar cell is also required to have excellent photoelectric conversion characteristics. For example, in the photoelectric conversion element of this dye-sensitized solar cell, a photoelectrode layer in which a ruthenium-based dye is adsorbed on a fired porous titanium oxide semiconductor has been conventionally used to improve photoelectric conversion characteristics. Various materials have been studied for the photoelectrode layer. Regarding this photoelectrode layer, Patent Document 1 describes that it is possible to achieve excellent photoelectric conversion characteristics by using a sensitizing dye adsorbed on zinc oxide deposited by cathode electrodeposition. .

By the way, the solar cell is used in various electric products such as a desk calculator, and the solar cell used in the electric product is arranged on the surface of the electric product to receive light. Therefore, in recent years, it has also been demanded to enhance the beauty of the solar cell itself. In response to such demands, it may be possible to prepare sensitizing dyes of various shades according to the design of the electrical product, but conventional sensitizing dyes are limited in usable dyes in terms of photoelectric conversion characteristics. In particular, no blue colorant has been found that satisfies photoelectric conversion characteristics. For example, in a study using a squarylium dye that is a blue dye (see Patent Documents 2 and 3), a result showing a relatively good photoelectric conversion characteristic as a blue dye may be obtained. The photoelectric conversion characteristics obtained with the dyes are still insufficient as compared with the values obtained with the red dyes, and further improvements are required.
That is, the conventional photosensitizing dye has a problem that the photoelectric conversion characteristics of the blue dye are not sufficiently improved, and it is difficult to satisfy the demand for enhancing the aesthetics of the solar cell. Have a problem.
The problem that the photoelectric conversion characteristics of the blue sensitizing dye are not sufficiently improved is not only for the purpose of improving the aesthetics of the solar cell for electric products but also for the blue sensitizing dye used for the dye sensitized photoelectric conversion element. It is a problem common to all pigments.

Japanese Patent Laid-Open No. 2004-6235 JP 2003-109676 A JP 2004-319309 A

  An object of the present invention is to provide a blue sensitizing dye having improved photoelectric conversion characteristics.

（なお、Ｒ₁₁、Ｒ₁₂は炭素数１〜１０のアルキル基であり、Ｒ₁₁、Ｒ₁₂の炭素数は、同じであっても異なっていてもよい。Ｒ₁₃、Ｒ₁₄は、同じ炭素数あるいは異なる炭素数を有するアルキル基がそれぞれ独立しているか、Ｒ₁₃、Ｒ₁₄が互いに結合して脂環族構造を形成しているかのいずれかであり、Ｒ₁₃、Ｒ₁₄の合計炭素数は、２〜２５である。また、ｎは１〜３の整数を表す。） As a result of intensive studies on improving the photoelectric conversion characteristics of blue sensitizing dyes, the present inventors have found that squarylium dyes having a specific structure have superior photoelectric conversion characteristics compared to conventional squarylium dyes. As a result, the present invention has been completed.
That is, the present invention has been made to solve the above-mentioned problems, and the invention according to claim 1 relating to a sensitizing dye is used for a dye-sensitized photoelectric conversion element and is represented by the following general formula (1). It is characterized by having a structure.

(Note that R ₁₁ and R ₁₂ are alkyl groups having 1 to 10 carbon atoms, and the carbon numbers of R ₁₁ and R ₁₂ may be the same or different. R ₁₃ and R ₁₄ are the same carbon. The alkyl groups having different numbers or different carbon numbers, or R ₁₃ and R ₁₄ are bonded to each other to form an alicyclic structure, and the total number of carbon atoms of R ₁₃ and R ₁₄ Is 2 to 25. Moreover, n represents an integer of 1 to 3.)

（なお、Ｒ₂₁、Ｒ₂₂は炭素数１〜１０のアルキル基、Ｒ₂₃、Ｒ₂₄は炭素数１〜５のアルキル基でありＲ₂₁、Ｒ₂₂の炭素数は、同じであっても異なっていてもよく、Ｒ₂₃、Ｒ₂₄の炭素数は、同じであっても異なっていてもよい。また、ｎは１〜３の整数を表す。） The invention according to claim 2 relating to a sensitizing dye is used for a dye-sensitized photoelectric conversion element and has a structure represented by the following general formula (2).

(Note that R ₂₁ and R ₂₂ are alkyl groups having 1 to 10 carbon atoms, R ₂₃ and R ₂₄ are alkyl groups having 1 to 5 carbon atoms, and the carbon numbers of R ₂₁ and R ₂₂ are the same or different. And the carbon number of R ₂₃ and R ₂₄ may be the same or different, and n represents an integer of 1 to 3.)

（なお、Ｒ₃₁、Ｒ₃₂は炭素数１〜１０のアルキル基、Ｒ₃₃、Ｒ₃₄は炭素数１〜５のアルキル基でありＲ₃₁、Ｒ₃₂の炭素数は、同じであっても異なっていてもよく、Ｒ₃₃、Ｒ₃₄の炭素数は、同じであっても異なっていてもよい。また、ｎは１〜３の整数を表す。） The invention according to claim 3 relating to a sensitizing dye is used for a dye-sensitized photoelectric conversion element and has a structure represented by the following general formula (3).

(Note that R ₃₁ and R ₃₂ are alkyl groups having 1 to 10 carbon atoms, R ₃₃ and R ₃₄ are alkyl groups having 1 to 5 carbon atoms, and the carbon numbers of R ₃₁ and R ₃₂ are the same or different. And the carbon number of R ₃₃ and R ₃₄ may be the same or different, and n represents an integer of 1 to 3.)

  The invention according to claim 4 relating to a dye-sensitized photoelectric conversion element includes a photoelectrode layer using the sensitizing dye according to any one of claims 1 to 3. Yes.

  The invention according to claim 5 relating to the dye-sensitized photoelectric conversion element is the dye-sensitized photoelectric conversion element according to claim 4, wherein the photoelectrode layer is any one of claims 1 to 3. An alcohol solution containing the sensitizing dye is impregnated into the porous zinc oxide in the presence of deoxycholic acid.

  Furthermore, the invention according to claim 6 relating to the dye-sensitized solar cell is characterized in that the dye-sensitized photoelectric conversion element according to claim 4 or 5 is used.

  According to the present invention, since the squarylium dyes as shown in the general formulas (1) to (3) are used, the sensitizing dye is improved in photoelectric conversion characteristics as compared with the conventional blue sensitizing dye. Blue-based sensitizing dye.

  A preferred embodiment of the present invention will be described below with reference to FIG. 1 by taking a photoelectric conversion element as an example.

The dye-sensitized photoelectric conversion element 10 (hereinafter also simply referred to as “photoelectric conversion element”) in the present embodiment was formed in a transparent plate shape having the first conductive film 3 formed by a transparent electrode. An electrode base 2 and a counter substrate 6 provided with a second conductive film 5 are used. The electrode base 2 and the counter substrate 6 are arranged with their conductive films facing each other. In addition, a photoelectrode layer 1 and an electrolyte layer 4 are formed between the opposing conductive films, and the photoelectrode layer 1 is arranged so that one side is in contact with the first conductive film 3. The other side is in contact with the electrolyte layer 4. The electrolyte layer 4 is arranged so that one surface side is in contact with the photoelectrode layer 1 as described above and the other surface side is in contact with the second conductive film 5.
In the dye-sensitized photoelectric conversion element 10, light from the sun S is transmitted through the electrode substrate 2 and irradiated to the photoelectrode layer 1, whereby the photoelectrode layer 1 is excited and electrons move. An electromotive force is generated by what happens.

  The substrate 7 of the electrode substrate 2 is formed using highly transparent glass, tempered glass, or a highly transparent synthetic resin such as polycarbonate resin, acrylic resin, polyarylate resin, polymethacrylate, or polyvinyl chloride. be able to.

  As a material used for the transparent electrode for forming the first conductive film 3 of the electrode substrate 2, tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), gold, platinum, etc., or a combination of these These can be directly formed on the surface of the transparent plate by a method such as vacuum deposition, sputter deposition, ion plating, chemical vapor deposition (CVD), or electrophoretic deposition, or The electrode substrate 2 in which the first conductive film 3 is formed on the surface of the transparent plate can be obtained by sticking the film on which these are formed to the substrate 7.

The base 8 of the counter substrate 6 can be formed using the same material as the transparent plate of the electrode base 2 when, for example, transparency is required. When arranged so as to be in direct contact with the electrolytic solution, it is preferable to use a polyester resin or a polyolefin resin in that the durability against the electrolytic solution can be improved.
Examples of the polyester resin include polyethylene terephthalate resin and polyethylene naphthalate resin. Examples of the polyolefin resin include polyethylene, polypropylene, and cyclic polyolefin resin.

  For the electrode material forming the second conductive film 5 of the counter electrode 6, for example, when transparency is required, the same material as the transparent electrode forming the first conductive film 3 is used. Can be formed in the same manner. Moreover, when transparency etc. are not required, it can form using carbon, a conductive polymer, a general metal, etc.

The photoelectrode layer 1 is made of, for example, Fe ₂ O ₃ , Cu ₂ O, In ₂ O ₃ , WO ₃ , Fe ₂ TiO ₃ , PbO, V ₂ O ₅ , FeTiO ₃ , Bi ₂ O ₃ , Nb ₂ O _3. , SrTiO ₃ , ZnO, BaTiO ₃ , CaTiO ₃ , KTaO ₃ , SnO ₂ , ZrO _2, etc., can be formed by supporting a sensitizing dye on a semiconductor layer.
As the semiconductor layer, it is preferable to use ZnO (zinc oxide) in terms of increasing cost, workability, and transparency of the semiconductor layer and facilitating thinning.

（なお、Ｒ₁₁、Ｒ₁₂は炭素数１〜１０のアルキル基であり、Ｒ₁₁、Ｒ₁₂の炭素数は、同じであっても異なっていてもよい。Ｒ₁₃、Ｒ₁₄は、同じ炭素数あるいは異なる炭素数を有するアルキル基がそれぞれ独立しているか、Ｒ₁₃、Ｒ₁₄が互いに結合して脂環族構造を形成しているかのいずれかであり、Ｒ₁₃、Ｒ₁₄の合計炭素数は、２〜２５である。また、ｎは１〜３の整数を表す。） As the sensitizing dye, those having the structures represented by the general formulas (1) to (3) can be used. For example, the following general formulas (1), (3), (4) What has the structure represented by (7) can be used.

(Note that R ₁₁ and R ₁₂ are alkyl groups having 1 to 10 carbon atoms, and the carbon numbers of R ₁₁ and R ₁₂ may be the same or different. R ₁₃ and R ₁₄ are the same carbon. The alkyl groups having different numbers or different carbon numbers, or R ₁₃ and R ₁₄ are bonded to each other to form an alicyclic structure, and the total number of carbon atoms of R ₁₃ and R ₁₄ Is 2 to 25. Moreover, n represents an integer of 1 to 3.)

Incidentally, the point indicating the excellent photoelectric conversion characteristics, it is preferable that the position of the R _11, R ₁₂ is C ₈ H ₁₇ together. Moreover, the positions of R ₁₃ and R ₁₄ are both CH ₃ as shown in the following general formula (4), C ₄ H ₉ as shown in the following general formula (5), or R _13. And R ₁₄ are bonded to each other to form a cyclohexane structure as shown in the following general formula (6), or they are both C as shown in the following general formula (7). it is preferable for ₈ H ₁₇ either. In particular, as shown in the general formula (5), it is preferable that both positions of R ₁₃ and R ₁₄ are C ₄ H ₉ .
Moreover, when the position of R < ₁₃ >, R < ₁₄ > is an aromatic group or an alkyl group substituted aromatic group, it is preferable that they are any of a phenyl group, a tolyl group, and a naphthyl group.

（なお式４中の、ｎは１〜３の整数を表す。）

(In formula 4, n represents an integer of 1 to 3)

（なお式５中の、ｎは１〜３の整数を表す。）

(In formula 5, n represents an integer of 1 to 3)

（なお式６中の、ｎは１〜３の整数を表す。）

(In formula 6, n represents an integer of 1 to 3.)

（なお式７中の、ｎは１〜３の整数を表す。）

(In formula 7, n represents an integer of 1 to 3)

（なお、Ｒ₃₁、Ｒ₃₂は炭素数１〜１０のアルキル基、Ｒ₃₃、Ｒ₃₄は炭素数１〜５のアルキル基でありＲ₃₁、Ｒ₃₂の炭素数は、同じであっても異なっていてもよく、Ｒ₃₃、Ｒ₃₄の炭素数は、同じであっても異なっていてもよい。また、ｎは１〜３の整数を表す。）

(Note that R ₃₁ and R ₃₂ are alkyl groups having 1 to 10 carbon atoms, R ₃₃ and R ₃₄ are alkyl groups having 1 to 5 carbon atoms, and the carbon numbers of R ₃₁ and R ₃₂ are the same or different. And the carbon number of R ₃₃ and R ₃₄ may be the same or different, and n represents an integer of 1 to 3.)

As a method for supporting such a sensitizing dye on the semiconductor layer, for example, the semiconductor layer is formed to be porous, and the porous semiconductor layer is impregnated with a solution containing the sensitizing dye. Can do.
In particular, when the semiconductor layer is formed of a zinc oxide porous body, the sensitizing dye represented by the general formulas (1) to (3) is used as an alcohol solution, and deoxychol is added to the zinc oxide porous body. The impregnation in the presence of an acid can further increase the photoelectric conversion efficiency.

  The electrolyte layer 4 is a liquid electrolyte such as a mixture of acetonitrile and ethylene carbonate, a liquid electrolyte such as methoxypropionitrile or the like to which an electrolyte made of iodide such as metal iodine or lithium iodide is added, or a polymer gel. It can be formed using a quasi-solidified electrolyte such as an electrolytic solution, a solid electrolyte such as a p-type semiconductor and a hole transport agent.

In addition, by forming a solar cell using such a photoelectric conversion element, a solar cell excellent in aesthetics and photoelectric conversion characteristics can be obtained.
In the present embodiment, the case where the sensitizing dye is used for a photoelectric conversion element in combination with the above-described member using the above-described material has been described as an example. However, the above-described material is used for the sensitizing dye of the present invention. In addition, the use thereof is not limited when used in a photoelectric conversion element in combination with the above members.

EXAMPLES Next, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to these.
(Examples 1-5, Comparative Examples 1-4)
The following were prepared as squarylium pigments for the examples and comparative examples.

上記中間体１（０．０４９ｇ）、中間体２（０．０５９ｇ）、トルエン／n−ブタノール（ｖ/ｖ＝1：1）混合溶媒３ｍＬを混合し、Ｄｅａｎ−ｓｔａｒｋ管を用いて２時間還流反応させた。反応溶液を濃縮し、シリカゲルカラムクロマトグラフィー（展開溶媒は、ジクロロメタンとメタノール９：１の混合溶液）を用いて精製し、実施例１のスクアリリウム色素を０．０１６ｇ得た。なお、得られた色素が上記構造となっていることは、¹Ｈ−ＮＭＲによる同定で確認した。また、この実施例１のスクアリリウム色素のエタノール中での極大吸収波長は６２０ｎｍであった。 In addition, the squarylium pigment | dye of Example 1 was synthesize | combined as follows.

Intermediate 1 (0.049 g), Intermediate 2 (0.059 g), and 3 mL of toluene / n-butanol (v / v = 1: 1) mixed solvent are mixed and refluxed using a Dean-stark tube for 2 hours. Reacted. The reaction solution was concentrated and purified using silica gel column chromatography (developing solvent was a mixed solution of dichloromethane and methanol 9: 1) to obtain 0.016 g of the squarylium dye of Example 1. In addition, it confirmed by the identification by < ¹ > H-NMR that the obtained pigment | dye has the said structure. Further, the maximum absorption wavelength of the squarylium dye of Example 1 in ethanol was 620 nm.

上記中間体３（０．４１１ｇ）、中間体２（０．４１４ｇ）、キノリン０．１ｍＬ、トルエン／n−ブタノール（ｖ/ｖ＝1：1）混合溶媒１０ｍＬを混合し、Ｄｅａｎ−ｓｔａｒｋ管を用いて６時間還流反応させた。反応溶液を濃縮し、シリカゲルカラムクロマトグラフィー（展開溶媒は、ジクロロメタンとメタノール９：１の混合溶液）を用いて精製し、実施例２のスクアリリウム色素を０．０４７ｇ得た。なお、得られた色素が上記構造となっていることは、¹Ｈ−ＮＭＲによる同定で確認した。また、この実施例２のスクアリリウム色素のエタノール中での極大吸収波長は６３５ｎｍであった。 In addition, the squarylium pigment | dye of Example 2 was synthesize | combined as follows.

The above intermediate 3 (0.411 g), intermediate 2 (0.414 g), quinoline 0.1 mL, toluene / n-butanol (v / v = 1: 1) mixed solvent 10 mL are mixed, and a Dean-stark tube is connected. And refluxed for 6 hours. The reaction solution was concentrated and purified using silica gel column chromatography (developing solvent was a mixed solution of dichloromethane and methanol 9: 1) to obtain 0.047 g of the squarylium dye of Example 2. In addition, it confirmed by the identification by < ¹ > H-NMR that the obtained pigment | dye has the said structure. In addition, the maximum absorption wavelength of the squarylium dye of Example 2 in ethanol was 635 nm.

上記中間体４（０．１３７ｇ）、中間体２（０．１２８ｇ）、トルエン／n−ブタノール（ｖ/ｖ＝1：1）混合溶媒３ｍＬを混合し、Ｄｅａｎ−ｓｔａｒｋ管を用いて２時間還流反応させた。反応溶液を濃縮し、シリカゲルカラムクロマトグラフィー（展開溶媒は、ジクロロメタンとメタノール９：１の混合溶液）を用いて精製し、実施例３のスクアリリウム色素を０．０８０ｇ得た。なお、得られた色素が上記構造となっていることは、¹Ｈ−ＮＭＲによる同定で確認した。また、この実施例３のスクアリリウム色素のエタノール中での極大吸収波長は６２３ｎｍであった。 In addition, the squarylium pigment | dye of Example 3 was synthesize | combined as follows.

The above intermediate 4 (0.137 g), intermediate 2 (0.128 g), and toluene / n-butanol (v / v = 1: 1) mixed solvent 3 mL are mixed and refluxed using a Dean-stark tube for 2 hours. Reacted. The reaction solution was concentrated and purified using silica gel column chromatography (developing solvent was a mixed solution of dichloromethane and methanol 9: 1) to obtain 0.080 g of the squarylium dye of Example 3. In addition, it confirmed by the identification by < ¹ > H-NMR that the obtained pigment | dye has the said structure. Further, the maximum absorption wavelength of the squarylium dye of Example 3 in ethanol was 623 nm.

上記中間体５（０．１２０ｇ）、中間体２（０．１２４ｇ）、トルエン／n−ブタノール（ｖ/ｖ＝1：1）混合溶媒３ｍＬを混合し、Ｄｅａｎ−ｓｔａｒｋ管を用いて２時間還流反応させた。反応溶液を濃縮し、シリカゲルカラムクロマトグラフィー（展開溶媒は、ジクロロメタンとメタノール９：１の混合溶液）を用いて精製し、実施例４のスクアリリウム色素を０．０８５ｇ得た。なお、得られた色素が上記構造となっていることは、¹Ｈ−ＮＭＲによる同定で確認した。また、この実施例４のスクアリリウム色素のエタノール中での極大吸収波長は６２４ｎｍであった。 In addition, the squarylium pigment | dye of Example 4 was synthesize | combined as follows.

The above intermediate 5 (0.120 g), intermediate 2 (0.124 g), and toluene / n-butanol (v / v = 1: 1) mixed solvent 3 mL are mixed and refluxed using a Dean-stark tube for 2 hours. Reacted. The reaction solution was concentrated and purified using silica gel column chromatography (developing solvent was a mixed solution of dichloromethane and methanol 9: 1) to obtain 0.085 g of the squarylium dye of Example 4. In addition, it confirmed by the identification by < ¹ > H-NMR that the obtained pigment | dye has the said structure. Further, the maximum absorption wavelength of the squarylium dye of Example 4 in ethanol was 624 nm.

上記中間体６（０．１０４ｇ）、中間体２（０．０７９ｇ）、トルエン／n−ブタノール（ｖ/ｖ＝1：1）混合溶媒３ｍＬを混合し、Ｄｅａｎ−ｓｔａｒｋ管を用いて２時間還流反応させた。反応溶液を濃縮し、シリカゲルカラムクロマトグラフィー（展開溶媒は、ジクロロメタンとメタノール９：１の混合溶液）を用いて精製し、実施例５のスクアリリウム色素を０．０４１ｇ得た。なお、得られた色素が上記構造となっていることは、¹Ｈ−ＮＭＲによる同定で確認した。また、この実施例５のスクアリリウム色素のエタノール中での極大吸収波長は６２５ｎｍであった。 In addition, the squarylium pigment | dye of Example 5 was synthesize | combined as follows.

The above intermediate 6 (0.104 g), intermediate 2 (0.079 g), and toluene / n-butanol (v / v = 1: 1) mixed solvent 3 mL are mixed and refluxed using a Dean-stark tube for 2 hours. Reacted. The reaction solution was concentrated and purified using silica gel column chromatography (developing solvent was a mixed solution of dichloromethane and methanol 9: 1) to obtain 0.041 g of the squarylium dye of Example 5. In addition, it confirmed by the identification by < ¹ > H-NMR that the obtained pigment | dye has the said structure. Further, the maximum absorption wavelength in ethanol of the squarylium dye of Example 5 was 625 nm.

上記中間体１（０．１７９ｇ）、中間体７（０．２６１ｇ）、キノリン０．１ｍＬ、トルエン／n−ブタノール（ｖ/ｖ＝1：1）混合溶媒１０ｍＬを混合し、Ｄｅａｎ−ｓｔａｒｋ管を用いて５時間還流反応させた。反応溶液を濃縮し、シリカゲルカラムクロマトグラフィー（展開溶媒は、ジクロロメタンとメタノール９：１の混合溶液）を用いて精製し、比較例１のスクアリリウム色素を０．０６６ｇ得た。なお、得られた色素が上記構造となっていることは、¹Ｈ−ＮＭＲによる同定で確認した。また、この比較例１のスクアリリウム色素のエタノール中での極大吸収波長は６２１ｎｍであった。 In addition, the squarylium pigment | dye of the comparative example 1 was synthesize | combined as follows.

The above intermediate 1 (0.179 g), intermediate 7 (0.261 g), quinoline 0.1 mL, toluene / n-butanol (v / v = 1: 1) mixed solvent 10 mL are mixed, and a Dean-stark tube is connected. And refluxed for 5 hours. The reaction solution was concentrated and purified using silica gel column chromatography (developing solvent was a mixed solution of dichloromethane and methanol 9: 1) to obtain 0.066 g of the squarylium dye of Comparative Example 1. In addition, it confirmed by the identification by < ¹ > H-NMR that the obtained pigment | dye has the said structure. Further, the maximum absorption wavelength in ethanol of the squarylium dye of Comparative Example 1 was 621 nm.

上記中間体１（０．１０２ｇ）、中間体８（０．０９２ｇ）、キノリン０．１ｍＬ、トルエン／n−ブタノール（ｖ/ｖ＝1：1）混合溶媒３ｍＬを混合し、Ｄｅａｎ−ｓｔａｒｋ管を用いて５時間還流反応させた。反応溶液を濃縮し、シリカゲルカラムクロマトグラフィー（展開溶媒は、ジクロロメタンとメタノール９：１の混合溶液）を用いて精製し、比較例２のスクアリリウム色素を０．０５１ｇ得た。なお、得られた色素が上記構造となっていることは、¹Ｈ−ＮＭＲによる同定で確認した。また、この比較例２のスクアリリウム色素のエタノール中での極大吸収波長は６４２ｎｍであった。 In addition, the squarylium pigment | dye of the comparative example 2 was synthesize | combined as follows.

The above intermediate 1 (0.102 g), intermediate 8 (0.092 g), quinoline 0.1 mL, toluene / n-butanol (v / v = 1: 1) mixed solvent 3 mL are mixed, and a Dean-stark tube is connected. And refluxed for 5 hours. The reaction solution was concentrated and purified using silica gel column chromatography (developing solvent was a mixed solution of dichloromethane and methanol 9: 1) to obtain 0.051 g of the squarylium dye of Comparative Example 2. In addition, it confirmed by the identification by < ¹ > H-NMR that the obtained pigment | dye has the said structure. Further, the maximum absorption wavelength in ethanol of the squarylium dye of Comparative Example 2 was 642 nm.

上記中間体９（０．３３７ｇ）、中間体２（０．４１４ｇ）、キノリン０．１ｍＬ、トルエン／n−ブタノール（ｖ/ｖ＝1：1）混合溶媒１０ｍＬを混合し、Ｄｅａｎ−ｓｔａｒｋ管を用いて５時間還流反応させた。反応溶液を濃縮し、シリカゲルカラムクロマトグラフィー（展開溶媒は、ジクロロメタンとメタノール９：１の混合溶液）を用いて精製し、比較例３のスクアリリウム色素を０．０８５ｇ得た。なお、得られた色素が上記構造となっていることは、¹Ｈ−ＮＭＲによる同定で確認した。また、この比較例３のスクアリリウム色素のエタノール中での極大吸収波長は６３０ｎｍであった。 In addition, the squarylium pigment | dye of the comparative example 3 was synthesize | combined as follows.

The above intermediate 9 (0.337 g), intermediate 2 (0.414 g), quinoline 0.1 mL, toluene / n-butanol (v / v = 1: 1) mixed solvent 10 mL are mixed, and a Dean-stark tube is connected. And refluxed for 5 hours. The reaction solution was concentrated and purified using silica gel column chromatography (developing solvent was a mixed solution of dichloromethane and methanol 9: 1) to obtain 0.085 g of the squarylium dye of Comparative Example 3. In addition, it confirmed by the identification by < ¹ > H-NMR that the obtained pigment | dye has the said structure. The maximum absorption wavelength in ethanol of the squarylium dye of Comparative Example 3 was 630 nm.

上記中間体１（０．５８７ｇ）、化合物ａ（０．２０１ｇ）、キノリン０．６ｍＬ、トルエン／ベンゼン（ｖ/ｖ＝1：1）混合溶媒１０ｍＬを混合し、Ｄｅａｎ−ｓｔａｒｋ管を用いて１９時間還流反応させた。反応溶液を冷却して沈澱物を得た。該沈殿物をシリカゲルカラムクロマトグラフィー（展開溶媒は、ジクロロメタンとメタノール９：１の混合溶液）を用いて精製し、比較例４のスクアリリウム色素を０．５４４ｇ得た。なお、得られた色素が上記構造となっていることは、¹Ｈ−ＮＭＲによる同定で確認がなされている。また、この比較例４のスクアリリウム色素のエタノール中での極大吸収波長は６３０ｎｍであった。 In addition, the squarylium pigment | dye of the comparative example 4 was synthesize | combined as follows.

The above intermediate 1 (0.587 g), compound a (0.201 g), quinoline 0.6 mL, toluene / benzene (v / v = 1: 1) mixed solvent 10 mL were mixed, and 19 using a Dean-stark tube. The reaction was refluxed for an hour. The reaction solution was cooled to obtain a precipitate. The precipitate was purified using silica gel column chromatography (the developing solvent was a mixed solution of dichloromethane and methanol 9: 1) to obtain 0.544 g of the squarylium dye of Comparative Example 4. In addition, it is confirmed by identification by ¹ H-NMR that the obtained dye has the above structure. Moreover, the maximum absorption wavelength in ethanol of the squarylium dye of Comparative Example 4 was 630 nm.

(Creation of photoelectric conversion element)
(Create photoelectrode layer)
Using an FTO glass having an FTO electrode film formed on one side as an electrode substrate, a zinc oxide porous film having a thickness of 3 μm was formed on the electrode surface of the FTO glass by electrodeposition.
The FTO glass on which this zinc oxide porous body film was formed was immersed in the sensitizing dye solution of each example and comparative example for 1 hour to prepare a photoelectrode layer.
As this FTO glass, “SnO ₂ conductive substrate: A110U80” (thickness: 1.1 mm, surface resistance 9Ω / □, transmittance 82%) manufactured by Asahi Glass Co., Ltd. was used.
At this time, the following three types of sensitizing dye solutions were used.
Sensitizing dye solution 1: Sensitizing dye 100 μM / ethanol 10 mL
Sensitizing dye solution 2: (sensitizing dye 100 μM + DCA 1 mM) / ethanol 10 mL
Sensitizing dye solution 3: (sensitizing dye 100 μM + DCA 0.5 mM) / ethanol 10 mL
(DCA: deoxycholic acid)

(Formation of electrolyte layer)
To a solution in which acetonitrile and ethylene carbonate are mixed at a volume ratio of acetonitrile: ethylene carbonate = 1: 4, tetrapropylammonium iodide and iodine are mixed with tetrapropylammonium iodide at 0.5 mol / L and iodine at 0.05 mol / L. An electrolyte solution was prepared by mixing so as to be L.
This electrolyte solution was disposed between the counter substrate using the same FTO glass as the electrode base material and the above-mentioned photoelectrode layer, thereby forming an electrolyte layer.

(Evaluation)
Applying light at an irradiation intensity of 100 mW / cm ² using a “CEP-2000” manufactured by Spectrometer Co., Ltd. to a photoelectric conversion element (light receiving area 4 mm × 5 mm) using a sensitizing dye of each example and comparative example, The short-circuit current I ₀ (mA / cm ² ) and the open circuit voltage E ₀ (V) of the photoelectric conversion element were measured.
Subsequently, the maximum power Wmax was observed by changing the resistance value connected between the electrodes of the photoelectric conversion element, and the fill factor and the photoelectric conversion efficiency were obtained by calculation.
Table 1 shows the fill factor (ff) and photoelectric conversion efficiency (η) when the sensitizing dyes of Examples and Comparative Examples are used as the sensitizing dye solution 1 and the sensitizing dye solution 2.

  In the results of the sensitizing dye solution 1 in Table 1, the photoelectric conversion efficiencies of Examples 1 to 5 show large values for all the comparative examples, and in Examples 1 and 3, the photoelectric conversion efficiency is the smallest for the comparative examples. The photoelectric conversion efficiency was about twice, and a maximum of 15 times or more. Moreover, in the result of the sensitizing dye solutions 2 and 3, Examples 1-5 showed the outstanding photoelectric conversion efficiency of about 1.5 times or more with respect to all the comparative examples.

This also shows that the squarylium-based sensitizing dye having the structures of the above formulas (1) to (3) can be made superior in photoelectric conversion efficiency as compared with the conventional squarylium-based dye. In particular, it can be seen that the squarylium-based sensitizing dye having the structure of the formula (5) is excellent in photoelectric conversion efficiency.
Therefore, it turns out that it can be set as the blue sensitizing dye by which the photoelectric conversion characteristic was improved compared with the conventional blue sensitizing dye by making a sensitizing dye into the structure of said Formula (1)-(3).

The fragmentary sectional view which shows the dye-sensitized photoelectric conversion element of one Embodiment.

Explanation of symbols

  1: photoelectrode layer, 2: electrode base material, 3: first conductive film, 4: electrolyte layer, 5: second conductive film, 6: counter substrate, 10: dye-sensitized photoelectric conversion element

Claims (6)

A sensitizing dye that is used in a dye-sensitized photoelectric conversion element and has a structure represented by the following general formula (1) .

(Note that R ₁₁ and R ₁₂ are alkyl groups having 1 to 10 carbon atoms, and the carbon numbers of R ₁₁ and R ₁₂ may be the same or different. R ₁₃ and R ₁₄ are the same carbon. The alkyl groups having different numbers or different carbon numbers, or R ₁₃ and R ₁₄ are bonded to each other to form an alicyclic structure, and the total number of carbon atoms of R ₁₃ and R ₁₄ Is 2 to 25. Moreover, n represents an integer of 1 to 3.) A sensitizing dye that is used in a dye-sensitized photoelectric conversion element and has a structure represented by the following general formula (2) .

(Note that R ₂₁ and R ₂₂ are alkyl groups having 1 to 10 carbon atoms, R ₂₃ and R ₂₄ are alkyl groups having 1 to 5 carbon atoms, and the carbon numbers of R ₂₁ and R ₂₂ are the same or different. And the carbon number of R ₂₃ and R ₂₄ may be the same or different, and n represents an integer of 1 to 3.) A sensitizing dye which is used in a dye-sensitized photoelectric conversion element and has a structure represented by the following general formula (3) .

(Note that R ₃₁ and R ₃₂ are alkyl groups having 1 to 10 carbon atoms, R ₃₃ and R ₃₄ are alkyl groups having 1 to 5 carbon atoms, and the carbon numbers of R ₃₁ and R ₃₂ are the same or different. And the carbon number of R ₃₃ and R ₃₄ may be the same or different, and n represents an integer of 1 to 3.)   A dye-sensitized photoelectric conversion element comprising a photoelectrode layer in which the sensitizing dye according to claim 1 is used.   5. The photoelectrode layer is formed by impregnating a porous zinc oxide with an alcohol solution containing the sensitizing dye according to any one of claims 1 to 3 in the presence of deoxycholic acid. Dye-sensitized photoelectric conversion element.   A dye-sensitized solar cell, wherein the dye-sensitized photoelectric conversion element according to claim 4 or 5 is used.

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