JP2014053263A - Dye-sensitized solar battery, dye-sensitized solar battery module and method of manufacturing organic dye - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the durability of a dye-sensitized solar battery.SOLUTION: A dye-sensitized solar battery module 10 includes a plurality of dye-sensitized solar batteries 40. Each dye-sensitized solar battery 40 includes: a photoelectrode 20 including a porous semiconductor layer 24 containing an organic dye on a transparent conductive substrate 14; a counter electrode 30 arranged so as to be opposed to the photoelectrode 20; and an electrolyte layer 26 including an electrolyte interposed between the photoelectrode 20 and the counter electrode 30. The organic dye has a cyanophosphoric acid group as an anchor group. The electrolyte contains ionic liquid. It is preferred that this dye has an indoline skeleton, and that the electrolyte includes an imidazolium salt. This organic dye is produced by a method of manufacturing an organic dye of introducing a phosphoric acid ester group to a compound having the indoline skeleton and an aldehyde group in acetonitrile, and performing hydrolysis of a reactant resulting from the introduction in dichloromethane by alcohol.

Description

  The present invention relates to a dye-sensitized solar cell, a dye-sensitized solar cell module, and a method for producing an organic dye.

  In recent years, various organic dye-based compounds having no metal have been proposed (for example, see Patent Document 1). This Patent Document 1 proposes a structure having an acidic group at the terminal and an organic residue or substituent bonded to a nitrogen atom. Further, the durability of a dye-sensitized solar cell using an organic dye having an indoline skeleton and a carboxylic acid as an anchor group has been studied in detail (for example, see Non-Patent Document 1). According to this Non-Patent Document 1, it becomes clear that carboxylic acid, which is an anchor group that binds titanium oxide and an organic dye, is decarboxylated during the durability test. As a result, the solar cell deteriorates and becomes durable. It is considered to be less prone.

JP 2007-84684 A

Solar Energy Materials & Solar Cells, 93 (2009), 1143-1148

As described above, Non-Patent Document 1 points out that it is necessary to use other than carboxylic acid as the anchor group. In this regard, Patent Document 1 discloses that in addition to carboxylic acid, phosphoric acid is used as an anchor group (for example, see Table 8 of Patent Document 1 and Comparative Example 2). However, when an organic solvent, such as acetonitrile, was used as the electrolyte, the durability as a solar cell was very low, such as a 50% reduction in conversion efficiency after 100 hours of exposure to AM1.5 simulated sunlight. In addition, in patent document 1, although the durability at the time of using an organic pigment | dye for a solar cell is examined, durability evaluation here is as durability tests, such as 100 hours by the light quantity of 100 mW / cm < ² >, It is considered to be a mild condition. There are still few literatures that have evaluated and published durability according to practical use. Thus, in the dye-sensitized solar cell using the organic dye, it has been demanded to further improve the durability.

  This invention is made | formed in view of such a subject, and provides the manufacturing method of the dye-sensitized solar cell which can improve durability more, a dye-sensitized solar cell module, and an organic dye. Main purpose.

  As a result of diligent research to achieve the above-described object, the present inventors have found that in an organic dye having an indoline skeleton, when an ionic liquid is used as an electrolytic solution after using a cyanophosphate group as an anchor group, the durability is improved. Has been found to be significantly improved, and the present invention has been completed. In addition, the present inventors introduced a phosphate ester group in acetonitrile to a compound having an indoline skeleton and an aldehyde group, and then hydrolyzed in dichloromethane to obtain an organic dye having a cyanophosphate group and an indoline skeleton in a yield. The inventors have found that they can be synthesized well and have completed the present invention.

That is, the dye-sensitized solar cell of the present invention is
A photoelectrode provided with a semiconductor layer containing an organic dye on a transparent conductive substrate, a counter electrode disposed so as to face the photoelectrode, and an electrolyte layer containing an electrolytic solution interposed between the photoelectrode and the counter electrode And comprising
The organic dye has a cyanophosphate group as an anchor group,
The electrolytic solution contains an ionic liquid.

  The dye-sensitized solar cell module of the present invention includes a plurality of the dye-sensitized solar cells described above.

The method for producing the organic dye of the present invention comprises:
(A) introducing a phosphate ester group into a compound having an indoline skeleton and an aldehyde group in acetonitrile;
(B) The reaction product in the step (a) is hydrolyzed with alcohol in dichloromethane to produce an organic dye having a cyanophosphate group and an indoline skeleton.

  The dye-sensitized solar cell and the dye-sensitized solar cell module of the present invention can further improve the durability. The reason why such an effect is obtained is not clear, but is presumed as follows. For example, in a dye-sensitized solar cell, the organic dye is formed on the surface of titanium oxide, which is an n-type semiconductor, for example. According to the theory of Hard and Soft Acids and Bases (HSAB), the chemical bond between titanium metal, which is a hard acid, and phosphoric acid, which is a hard base, becomes stronger even when the temperature of the solar cell is high, for example. It is presumed that the detachment into the liquid is further prevented and the durability of the solar cell is further improved. That is, it is presumed that the bond between atoms (molecules) becomes stronger at the phosphate group and the surface of the n-type semiconductor, thereby further suppressing the elimination of the organic dye. Moreover, since the phosphoric acid group has two hydroxyl groups, the adsorption state on the surface of the n-type semiconductor is more diverse than that of carboxylic acid, and it is presumed that the elimination of the organic dye is further suppressed. Moreover, from the viewpoint of pKa, carboxylic acid has one proton, whereas phosphoric acid has two protons and exhibits weak acidity. Is considered to be higher than carboxylic acid. In addition, by using a highly viscous ionic liquid with low vapor pressure and low volatility as the solvent of the electrolyte, the organic dye is less soluble in the organic solvent, thereby further suppressing the elimination of the organic dye. Inferred. As a result, it is presumed that the durability of the dye-sensitized solar cell can be further improved.

  In addition, the method for producing an organic dye of the present invention can synthesize an organic dye having a cyanophosphate group and an indoline skeleton with high yield. The reason why such an effect is obtained is not clear, but is presumed as follows. For example, it is speculated that the solvent used in each step is more suitable for the compound used as a raw material and the like, and the side reaction and the like are efficiently suppressed.

FIG. 3 is a cross-sectional view showing an example of a schematic configuration of the dye-sensitized solar cell module 10. Explanatory drawing of an example of the organic pigment | dye which has a cyanophosphate group. Explanatory drawing of an example of the organic pigment | dye which has a cyanophosphate group. FIG. 3 is a cross-sectional view illustrating an example of a schematic configuration of a dye-sensitized solar cell 40. A synthesis scheme of an organic dye having a cyanophosphate group introduced therein. The durability test evaluation result in 1 sun60 degreeC of Example 1 and the comparative example 1. FIG. The evaluation result of the 85 degreeC dark place heat endurance test of Example 1 and Comparative Example 1. FIG. The measurement result of the absorption spectrum of the solution containing an organic solvent, an ionic liquid, and an organic pigment. The measurement result of the light absorption spectrum of the organic pigment | dye of Example 1 and Comparative Example 1. FIG.

  An embodiment of the dye-sensitized solar cell module of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view illustrating an example of a schematic configuration of a dye-sensitized solar cell module 10. As shown in FIG. 1, the dye-sensitized solar cell module 10 according to this embodiment has a configuration in which a plurality of dye-sensitized solar cells 40 (hereinafter also referred to as cells) are sequentially arranged on a transparent conductive substrate 14. It has become. These cells are connected in series. In this dye-sensitized solar cell module 10, a sealing material 32 is formed so as to fill between the cells, and a flat protective member is provided on the surface of the sealing material 32 on the side opposite to the transparent conductive substrate 14. 34 is formed. The dye-sensitized solar cell 40 according to this embodiment includes a transparent conductive substrate 14 having a transparent conductive film 12 formed on the surface of a transparent substrate 11 through which light is transmitted, and a dye formed on the transparent conductive film 12. A porous semiconductor layer 24 and a counter electrode 30 provided on the porous semiconductor layer 24 via an electrolyte layer 26 are provided. The photoelectrode 20 is disposed on the transparent conductive substrate 14 and the transparent conductive film 12 formed separately on the surface opposite to the light receiving surface 13 of the transparent substrate 11 and is provided with a porous semiconductor layer 24 that emits electrons upon receiving light. It has. The dye-sensitized solar cell 40 includes an electrolyte layer 26 formed by containing an electrolyte in a porous body, and has a configuration capable of generating power via an electrolyte such as an ionic liquid.

  The dye-sensitized solar cell 40 of the present invention includes a photoelectrode 20 provided with a porous semiconductor layer 24 containing a dye on a transparent conductive substrate 14, a counter electrode 30 disposed so as to face the photoelectrode 20, a light An electrolyte layer 26 containing an electrolytic solution interposed between the electrode 20 and the counter electrode 30, the organic dye has a cyanophosphate group as an anchor group, and the electrolytic solution contains an ionic liquid.

The transparent conductive substrate 14 is composed of the transparent substrate 11 and the transparent conductive film 12, and has light transmittance and conductivity. Specific examples include fluorine-doped SnO ₂ coated glass, ITO coated glass, ZnO: Al coated glass, and antimony-doped tin oxide (SnO ₂ —Sb) coated glass. Also, a transparent electrode obtained by doping tin oxide or indium oxide with cations or anions having different valences, or a metal electrode having a structure capable of transmitting light such as a mesh shape or a stripe shape on a substrate such as a glass substrate Can be used. Current collecting electrodes 16 and 17 are provided at both ends of the transparent conductive substrate 14 on the transparent conductive film 12 side. Electric power generated by the dye-sensitized solar cell 40 via the current collecting electrodes 16 and 17 is provided. Can be used.

  Examples of the transparent substrate 11 include transparent glass, a transparent plastic plate, a transparent plastic film, and an inorganic transparent crystal, and among these, transparent glass is preferable. The transparent substrate 11 may be a transparent glass substrate, a glass substrate whose surface is appropriately roughened to prevent reflection of light, or a transparent glass substrate such as a ground glass-like translucent glass substrate. The transparent conductive film 12 can be formed, for example, by depositing tin oxide on the transparent substrate 11. In particular, if a metal oxide such as tin oxide (FTO) doped with fluorine is used, a suitable transparent conductive film 12 can be formed. In the transparent conductive film 12, grooves 18 are formed at predetermined intervals, and a plurality of regions of the transparent conductive film 12 are separately formed at intervals corresponding to the width of the grooves 18.

The porous semiconductor layer 24 is formed of a dye that is a photosensitizer and a porous n-type semiconductor layer containing the dye. As the n-type semiconductor, a metal oxide semiconductor or a metal sulfide semiconductor is suitable. For example, titanium oxide (TiO ₂ ), tin oxide (SnO ₂ ), zinc oxide (ZnO), cadmium sulfide (CdS), sulfide It is preferable that it is at least 1 or more among zinc (ZnS), and among these, porous titanium oxide is more preferable. By thinning these semiconductor materials into a microcrystalline or polycrystalline state, a good porous n-type semiconductor layer can be formed. In particular, the porous titanium oxide layer is suitable as an n-type semiconductor layer included in the photoelectrode 20. Further, as titanium oxide, anatase TiO ₂ is preferable to rutile TiO ₂ because the energy level at the lower end of the conduction band is higher and the open-circuit voltage is higher.

  An organic dye is a compound having a cyanophosphate group as an anchor group. This organic dye may further have an indoline skeleton represented by the following formula (1). Moreover, this organic pigment | dye is good also as what is represented by basic formula (2). The organic dye represented by the basic formula (2) is bright yellow. For this reason, if this is used, it can contribute to the diversity of the color variation of a solar cell panel. In addition, an anchor group is a functional group couple | bonded with an n-type semiconductor, for example, What has a hydroxyl group at the terminal etc. is mentioned, for example. Moreover, it is good also as an organic pigment | dye which has a cyano phosphate group as an anchor group as shown in FIG. For example, organic dyes C201P to C208P, C211P, C212P, JK2P, JK45P, JK46P, D21L6P, etc. having an anchor group such as organic dyes C201 to C208, C211, C212, JK2, JK45, JK46, and D21L6 as cyanophosphate groups. (FIGS. 2 and 3). This organic dye may be adsorbed on the surface of a porous n-type semiconductor. This adsorption can be performed by chemical adsorption or physical adsorption. Specifically, after forming a porous n-type semiconductor layer on the transparent conductive substrate 14, a method of dropping a solution containing an organic dye onto the n-type semiconductor layer and drying it, or forming an n-type semiconductor layer The transparent conductive substrate 14 can be produced by immersing it in a solution containing an organic dye and then drying it.

  The electrolyte layer 26 is a layer that mediates the transfer of electrons between the counter electrode 30 and the photoelectrode 20, and may include, for example, a liquid or gel electrolyte. For example, the electrolyte layer 26 is preferably a layer containing an electrolytic solution in a porous body. The porous body is not particularly limited as long as it is capable of holding an electrolytic solution and does not have electron conductivity. For example, a porous body formed of rutile titanium oxide particles is used as the porous body. May be used. This porous body has a separator function. The porous body has a portion that covers the back surface 25 of the porous semiconductor layer 24 and a jaw-shaped edge portion that is in close contact with the side surface of the porous semiconductor layer 24 adjacent to the back surface 25. This bowl-shaped edge portion is in direct contact with the transparent substrate 11. In the connection portion between the transparent conductive substrate 14 and the porous body of the electrolyte layer 26, a part of the transparent conductive film 12 is completely scraped off by a technique such as laser scribing, and the surface of the transparent substrate 11 is exposed. A groove 18 having a depth is formed. The groove 18 is inserted with an edge portion of the electrolyte layer 26 formed in the shape of a bowl of a porous body.

  The electrolytic solution contained in the electrolyte layer 26 includes an ionic liquid. Examples of the ionic liquid include 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide (EMI-TFSI), 1-allyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide (AMII-TFSI). ), Imidazolium salts such as 1-ethyl-3-methylimidazolium tetracyanoborate (EMI-TCB) and 1-butyl-3-methylimidazolium tetrafluoroborate (BMI-BF4). If this ionic liquid is included, dissolution of the organic dye having a cyanophosphate group into the electrolytic solution can be further suppressed, and as a result, the durability of the solar cell can be further improved. In addition to the ionic liquid, the electrolyte includes, for example, a nitrile solvent such as methoxyproponitrile and acetonitrile, a lactone solvent such as γ-butyrolactone and valerolactone, and a carbonate system such as ethylene carbonate and propylene carbonate. One or more of the solvents and the like may be included.

The electrolytic solution contained in the electrolyte layer 26 may include a redox pair. This redox pair mediates the transfer of electrons between the photoelectrode 20 and the counter electrode 30. A part of the electrolytic solution is usually impregnated in the photoelectrode 20 which is a porous body. Examples of the redox pair include I ₃ ⁻ / I ⁻ , Br ₃ ⁻ / Br ⁻ , hydroquinone / quinone, cobalt ion, iron ion, etc. Among these, I ₃ ⁻ / I ⁻ is particularly preferably used. Can do. Moreover, it is preferable that an electrolytic solution contains an ionic liquid containing iodine as a redox pair (iodine ionic liquid). Examples of the iodine-based ionic liquid include 1-propyl-3-methylimidazolium iodide (hereinafter abbreviated as PMII), 1,2 dimethyl-3-propylimidazolium iodide (DMPII), 1- Butyl-3-methylimidazolium iodide, 1-hexyl-3-methylimidazolium iodide, 1-allyl-3-ethylimidazolium iodide, 1,3-dimethylimidazolium iodide, 1,2-dimethyl-3 -Propyl imidazolium iodide etc. are mentioned.

  The electrolyte solution contained in the electrolyte layer 26 may contain an additive. As an additive, for example, guanidine thiocyanate, 4-tert-butylpyridine, N-methyl-benzimidazole, and the like may be appropriately added. The concentration of the additive in the electrolytic solution is preferably in the range of 0.001 mol / L to 1.0 mol / L.

  The counter electrode 30 is formed in an L-shaped cross section having a bowl-shaped edge portion so as to contact the back surface 27 of the electrolyte layer 26 and the bowl-shaped edge portion. The counter electrode 30 is connected to the back surface of the electrolyte layer 26, and the flange-shaped edge portion is connected to the adjacent transparent conductive film 12 via the connection portion 21. The surface of the counter electrode 30 that is in contact with the back surface 27 of the electrolyte layer 26 faces the photoelectrode 20 at a predetermined interval. The counter electrode 30 is not particularly limited as long as it has conductivity and bondability with the electrolyte layer 26, and examples thereof include Pt, Au, and carbon. Among these, carbon is preferable. The counter electrode 30 may be, for example, a porous carbon electrode formed using carbon black particles, graphite particles, and conductive oxide particles such as anatase-type titanium oxide particles as constituent materials. The counter electrode 30 may be dispersedly supported with catalyst fine particles such as Pt fine particles, for example, from the viewpoint of more rapidly increasing the speed of the electrode reaction.

  The sealing material 32 is formed so as to cover the outer peripheral side of each dye-sensitized solar cell 40, and the main purpose is to prevent the electrolyte filled in the electrolyte layer 26 from leaking outside. Is provided. As the sealing material 32, for example, any insulating member can be used without any particular limitation, and a thermoplastic resin film such as polyethylene or ionomer resin, an epoxy adhesive, or the like can be used.

  The protection member 34 is a member that protects the dye-sensitized solar cell 40, and can be, for example, a moisture-proof film or protective glass.

  When the dye-sensitized solar cell 40 is irradiated with light from the light receiving surface 13 side of the transparent substrate 11, the light reaches the porous semiconductor layer 24 through the light receiving surface 15 and the light receiving surface 23 of the transparent conductive film 12. The dye absorbs light and generates electrons. Electrons move from the photoelectrode 20 to the adjacent counter electrode 30 via the transparent conductive film 12 and the connection portion 21. In the dye-sensitized solar cell 40, an electromotive force is generated by the movement of the electrons, and the power generation action of the battery is obtained. In this dye-sensitized solar cell module 10, the porous semiconductor layer 24 includes an organic dye having a cyanophosphate group as an anchor group, and the electrolyte layer 26 includes an electrolytic solution containing an ionic liquid. In particular, durability at high temperatures can be further improved. The reason is presumed as follows. In general, carboxylic acid is used in addition to phosphoric acid as the anchor group. In the dye-sensitized solar cell of the present invention, the bonding force between atoms (molecules) becomes stronger between the phosphate group and the titanium oxide surface of the porous semiconductor layer 24, or the phosphate group has two hydroxy groups. Because of this, the adsorption state of titanium oxide on the surface is more diverse than that of carboxylic acid, and phosphoric acid shows weak acidity with two protons. This is presumably because the organic dye is strongly adsorbed to the porous semiconductor layer 24 because it is higher than the carboxylic acid. In addition, since an ionic liquid with low vapor pressure and low volatility and high viscosity is used as the solvent of the electrolytic solution, the solubility of the organic dye is low with respect to the organic solvent, and desorption of the organic dye is further suppressed. Inferred. As a result, it is presumed that the durability of the dye-sensitized solar cell can be further improved. Moreover, since the organic pigment | dye represented by basic formula (2) is bright yellow, if it is used, it will be guessed that it can contribute to the diversity of the color variation of a solar cell panel.

  Next, a method for synthesizing the organic dye of the present invention will be described. The organic dye synthesis method of the present invention includes a step (a) of introducing a phosphate ester group into a compound having an indoline skeleton and an aldehyde group (hereinafter also referred to as a raw material compound) in acetonitrile, and a reaction in the step (a). And a step (b) of hydrolyzing the product with alcohol in dichloromethane to produce an organic dye having a cyanophosphate group and an indoline skeleton.

  In the step (a), a treatment for introducing a phosphate group into the raw material compound is performed. In this raw material compound, for example, a compound represented by the basic formula (3) is preferably used. In this step (a), it is preferable to react the raw material compound and diethyl cyanomethylphosphonate in acetonitrile. In this way, a phosphate group can be introduced into the raw material compound relatively easily. In this step (a), it is preferable to purify the reaction product using a mixed solvent for the silica column. As the mixed solvent, for example, a mixed solution of dichloromethane and ethyl acetate is preferably used. This facilitates purification of the reaction product. Moreover, it is more preferable to achieve high purity of the product using a Kugelrohr method. In this way, a reaction product (intermediate) can be obtained with a higher yield. In the Kugelrohr method, it is preferable to heat the impurities to 150 ° C.

  At a process (b), the process which hydrolyzes the reaction material in a process (a) is performed. In this step (b), it is preferable to add trimethylsilane iodide in dichloromethane to the reaction product of step (a) and stir, followed by hydrolysis with methanol. After hydrolysis, the product (target product) is preferably eluted and purified by gel filtration using methanol. By doing so, it is possible to produce an organic dye having a cyanophosphate group and an indoline skeleton as shown in the basic formula (2).

  In the method for producing an organic dye according to this embodiment described in detail above, an organic dye having a cyanophosphate group and an indoline skeleton can be synthesized with high yield. The reason why such an effect is obtained is presumed to be that, for example, the solvent used in each step is more suitable for the compound used as a raw material and the like, and the side reaction and the like are efficiently suppressed. .

  It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that the present invention can be implemented in various modes as long as it belongs to the technical scope of the present invention.

  For example, in the above-described embodiment, the dye-sensitized solar cell module 10 is used. However, the present invention is not particularly limited thereto, and the dye-sensitized solar cell 40 may be used. FIG. 4 is a cross-sectional view showing an example of a schematic configuration of the dye-sensitized solar cell 40. In FIG. 4, the same components as those described in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted. As shown in FIG. 4, in the dye-sensitized solar cell 40 alone, the electrolyte layer 26 and the counter electrode 30 are not L-shaped in cross section, and the plate-like edge portion is omitted to form a flat plate shape. Good. The counter electrode 30 may be, for example, one having the same configuration as that of the transparent conductive substrate 14, or may be one in which platinum is attached to the transparent conductive film 12, or a metal thin film such as platinum. Further, the electrolyte layer 26 may be configured such that the porous body is omitted and the electrolytic solution is accommodated in the space between the photoelectrode 20 and the counter electrode 30.

  Below, the example which produced the dye-sensitized solar cell 40 of this invention concretely is demonstrated as an Example.

[Synthesis of organic dyes]
FIG. 5 is a synthesis scheme of an organic dye (D131P) having a cyanophosphate group introduced therein. First, diethyl cyanomethylphosphonate, piperidine, and a compound having an indoline skeleton and an aldehyde group (formula (3)) in acetonitrile in a molar ratio of 1.0: 2.0: 1 0.0 and mixing at reflux for 2 hours. Next, the reaction product was purified by a silica column using a mixed solvent of dichloromethane and ethyl acetate having a mass ratio of 10: 1. Impurities were heated to 150 ° C. using a Kugelrohr method to obtain a high-purity target product. Structural analysis was performed using a ¹ H-NMR apparatus (ECX-400P manufactured by JEOL Ltd.) and an LC-MS mass spectrometer (Accu TOF JMS-T100LC manufactured by JEOL Ltd.), and the structure of the compound of formula (4) was confirmed. did. The yield was 81% by mass.

Next, 90 mg of the obtained reaction product was placed in 10 mL of dichloromethane, 200 μL of trimethylsilane iodide was added dropwise, and the mixture was stirred for 5 hours at room temperature. Then, after adding methanol and making it hydrolyze, it stirred at room temperature for 2 hours in the state which suppressed reaction. Subsequently, the desired product was eluted and purified by gel filtration using methanol. Structural analysis was performed using a ¹ H-NMR apparatus and a MALDI-MS mass spectrometer (Autoflex manufactured by Bruker Daltonics) to confirm the structure of the compound of formula (2). The yield was 92% by mass.

[Example 1]
A titania paste containing nanoparticles (average particle size 20 nm) of titanium oxide (TiO ₂ ), which is an n-type semiconductor, was applied to a glass substrate with a transparent conductive film (TCO) by a screen printing method. The coating film was dried at 150 ° C. and further baked by heating at 450 ° C. for 30 minutes to form a titania layer of nanoparticles. Further thereon, a porous semiconductor layer (titania layer) composed of titania particles (average particle diameter 400 nm) which is an n-type semiconductor was laminated by the same method to form a titania electrode. A solution (concentration: 0.3 mM) in which an organic dye was dissolved in a mixed solvent of acetonitrile and t-butanol (volume ratio 50%) was prepared, and the titania electrode was immersed in this solution. As the organic dye, a compound having an indoline skeleton and a cyanophosphate group represented by the formula (1) was used. After being immersed in a solution containing this dye, it was washed with acetonitrile to obtain a photoelectrode on which the dye was adsorbed.

  An alcohol solution of chloroplatinic acid was applied to a glass substrate with a TCO film, and the coating film was baked at 400 ° C. to produce a transparent counter electrode (counter electrode) formed from platinum nanoparticles (particle diameter: several nm). . The obtained counter electrode and the titania electrode were arranged opposite to each other, and these were bonded together via a sealing material (thermoplastic polyolefin resin). An electrolyte was injected from the injection hole between the photoelectrode and the counter electrode, and the injection hole was sealed. As an electrolytic solution, 65% by volume of 1-propyl-3-methylimidazolium iodide (PMII), 1-ethyl-3-methylimidazolium ion (EMI), bis (trifluoromethanesulfonyl) imide ion (TFSI), An ionic liquid consisting of 35% by volume is homogeneously mixed, and guanidine thiocyanate (GuSCN) is added at 0.5 mol /%, and 4-tert-butylpyridine (4TBP) is added as an additive having an electric charge. A mixture was used. The obtained cell was designated as the cell of Example 1.

[Comparative Example 1]
Comparative Example 1 was the same as Example 1 except that the organic dye was a compound of the following formula (5) having a cyanocarboxylic acid group as an anchor group instead of a cyanophosphoric acid group.

(Measurement of photoelectric conversion efficiency; durability evaluation test)
Using an AM1.5G solar simulator (WXS-85-H, manufactured by Wacom Denso) equipped with a 500 W xenon lamp and an IV tester (IV-9701, manufactured by Wacom Denso), Example 1 and Comparative Example 1 The current (I) -voltage (V) characteristic (IV characteristic) of the dye-sensitized solar cell was measured, and the photoelectric conversion efficiency was measured. The measurement was performed at 1 sun 60 ° C. for 100 days.

(85 ° C dark heat durability test)
The produced cell was kept in a dark place at 85 ° C., and the photoelectric conversion efficiency was measured at room temperature for each measurement time.

(Absorbance between organic solvent and ionic liquid and organic dye)
The organic dye of Example 1 was dissolved in various solvents, and the light absorption spectrum was examined. Here, the solvent was methoxypropyl nitrile (MPN), gamma butyrolactone (GBL), acetonitrile (AcCN), and imidazolium salt (EMI), and a solution in which an organic dye was dissolved was placed in a cell, and an absorption spectrum was measured. The absorption spectrum was measured with a spectrophotometer (U-3400 manufactured by Hitachi, Ltd.) in a wavelength region of 290 nm to 900 nm. Moreover, the light absorption spectrum of the organic pigment | dye of Example 1 and Comparative Example 1 was examined. Here, an absorption spectrum was measured by putting a solution in which an imidazolium salt was used as a solvent and an organic dye was dissolved into a cell. The absorption spectrum was measured in a wavelength region of 300 nm to 550 nm.

(Measurement results and discussion)
6 shows the results of durability test evaluation at 1 sun 60 ° C. in Example 1 and Comparative Example 1. FIG. FIG. 6 shows the retention rate (%) with respect to time, where the initial power generation efficiency is 1.0. Under the condition of 1 sun 60 ° C., no great difference in durability was observed for organic dyes having either carboxylic acid or phosphoric acid as an anchor group. FIG. 7 shows the evaluation results of the 85 ° C. dark heat durability test of Example 1 and Comparative Example 1. FIG. 7 shows the retention rate (%) with respect to time, where the initial power generation efficiency is 1.0. Under a high temperature condition of 85 ° C., the organic dye having phosphoric acid as an anchor group in Example 1 had higher durability. Therefore, it was assumed that the durability of the cell of Example 1 was higher than that of Comparative Example 1 if power generation was performed for a long time even under conditions below 85 ° C. FIG. 8 shows the results of measurement of absorption spectra of a solution containing an organic solvent, an ionic liquid, and an organic dye. As shown in FIG. 8, the organic dye (D131P) having phosphoric acid as an anchor group has high absorbance in an organic solvent, and thus easily dissolves. In an ionic liquid (imidazolium salt), the absorbance is low and thus hardly soluble. I understood it. Thus, it was found that the reduction of organic dye due to dissolution from the n-type semiconductor layer is one of the causes of deterioration of the dye-sensitized solar cell.

  FIG. 9 shows measurement results of light absorption spectra of the organic dyes of Example 1 and Comparative Example 1. The organic dye of Example 1 was found to have a shorter wavelength than the organic dye of Comparative Example 1. The organic dye of Comparative Example 1 showed an orange color, but the organic dye of Example 1 was bright yellow. Therefore, it was found that the use of the organic dye of the present invention can contribute to the diversity of color variations of the solar cell panel.

  The present invention can be used in the technical field of solar cells.

  10 Dye-sensitized solar cell module, 11 Transparent substrate, 12 Transparent conductive film, 13 Light receiving surface, 14 Transparent conductive substrate, 15 Light receiving surface, 16, 17 Current collecting electrode, 18 Groove, 20 Photo electrode, 21 Connection portion, 23 Photosensitive surface, 24 Porous semiconductor layer, 25 Back surface, 26 Electrolyte layer, 27 Back surface, 30 Counter electrode, 32 Sealing material, 34 Protection member, 40 Dye-sensitized solar cell.

Claims (9)

A photoelectrode provided with a semiconductor layer containing an organic dye on a transparent conductive substrate, a counter electrode disposed so as to face the photoelectrode, and an electrolyte layer containing an electrolytic solution interposed between the photoelectrode and the counter electrode And comprising
The organic dye has a cyanophosphate group as an anchor group,
The electrolyte solution is a dye-sensitized solar cell including an ionic liquid.   The dye-sensitized solar cell according to claim 1, wherein the organic dye further has an indoline skeleton. The dye-sensitized solar cell according to claim 1 or 2, wherein the organic dye is represented by the basic formula (1).

  The dye-sensitized solar cell according to any one of claims 1 to 3, wherein the electrolytic solution contains an imidazolium salt.   A dye-sensitized solar cell module comprising a plurality of the dye-sensitized solar cells according to any one of claims 1 to 4. (A) introducing a phosphate ester group into a compound having an indoline skeleton and an aldehyde group in acetonitrile;
(B) a step of hydrolyzing the reaction product in the step (a) with an alcohol in dichloromethane to produce an organic dye having a cyanophosphate group and an indoline skeleton;
The manufacturing method of the organic pigment | dye containing this. The method for producing an organic dye according to claim 6, wherein the compound represented by the basic formula (2) is used in the step (a).

  The method for producing an organic dye according to claim 6 or 7, wherein in the step (a), the compound and diethyl cyanomethylphosphonate are reacted in acetonitrile.   9. The process according to claim 6, wherein in the step (b), trimethylsilane iodide is added to and stirred in the reaction product of the step (a), followed by hydrolysis with methanol. A method for producing an organic dye.

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