JP5535718B2 - Composite, photoelectrode, dye-sensitized solar cell, and dye-sensitized solar cell module - Google Patents

Description

  The present invention relates to a composite, a photoelectrode, a dye-sensitized solar cell, and a dye-sensitized solar cell module.

  A dye-sensitized solar cell is a solar cell that is excited when a sensitizing dye adsorbed on a semiconductor material receives light, and generates a photocurrent by injecting electrons from the sensitizing dye into the semiconductor material. is there. Since this dye-sensitized solar cell has been proposed by Gretzel et al., It is expected to be put to practical use because of the advantages that the material used is inexpensive and that it can be manufactured by a relatively simple process. The dye-sensitized solar cell is required to have durability for sufficiently extending the battery life and high energy conversion efficiency for practical use. In order to improve the durability of the dye-sensitized solar cell, it is effective to use a sensitizing dye having excellent heat resistance, light resistance and chemical stability. As such a sensitizing dye, for example, Metal complex dyes in which a bidentate ligand in which bidentate ligands such as 2,2′-bipyridyl and the like are bonded to each other via a divalent group are coordinated to the metal have been proposed ( Patent Document 1).

JP 2003-3083 A

  However, the dye-sensitized solar cell of Patent Document 1 described above uses a metal complex dye excellent in heat resistance and the like, and although the durability of the dye-sensitized solar cell can be further improved, There was room for improvement. In addition, photoelectric conversion characteristics and the like are still not sufficient, and improvement of photoelectric conversion characteristics has been demanded.

  This invention is made | formed in view of such a subject, The composite body which can improve the light absorption characteristic of an organic pigment | dye more, a photoelectrode, a dye-sensitized solar cell, and a dye-sensitized solar cell module The main purpose is to provide.

  As a result of diligent research to achieve the above-described object, the present inventors have found that when an organic dye molecule having a CN group or rhodanine molecular structure is combined with a semiconductor containing Cu, the light absorption characteristics of the organic dye molecule are reduced. It has been found that the wavelength is extended to the long wavelength side, and the present invention has been completed.

  That is, the complex of the present invention includes an organic dye molecule having an electron accepting site containing at least one of S and N, and at least one of Cu, Ag, Au, Ni, Co, Cr, Pt, and Pd. And a metal-containing material that is at least one of the semiconductor and the conductor.

  The photoelectrode of the present invention is a photoelectrode used for a dye-sensitized solar cell, and an organic dye molecule having an electron accepting site containing at least one of S and N, and Cu, Ag, Au, Ni, Co, A composite containing a semiconductor containing at least one of Cr, Pt, and Pd and a metal-containing material that is at least one of conductors, and an n-type semiconductor on which organic dye molecules of the composite are adsorbed And a conductive substrate on which the n-type semiconductor layer is formed.

  The dye-sensitized solar cell of the present invention has a transparent substrate through which light is transmitted and a transparent conductive film is formed, and an electron accepting site that is provided adjacent to the transparent substrate and includes at least one of S and N A composite containing an organic dye molecule, a semiconductor containing at least one of Cu, Ag, Au, Ni, Co, Cr, Pt, and Pd, and a metal-containing material that is at least one of conductors, and the composite A photoelectrode comprising an n-type semiconductor layer on which organic dye molecules of the body are adsorbed and a conductive substrate on which the n-type semiconductor layer is formed, and a counter electrode provided adjacent to the photoelectrode It is provided.

  The dye-sensitized solar cell module of the present invention includes a transparent substrate on which light is transmitted and a transparent conductive film is formed, and an electron accepting site that is provided adjacent to the transparent substrate and includes at least one of S and N. A composite containing an organic dye molecule having a semiconductor containing at least one of Cu, Ag, Au, Ni, Co, Cr, Pt, and Pd and a metal-containing material that is at least one of conductors; A photoelectrode comprising an n-type semiconductor layer on which the organic dye molecules of the complex are adsorbed and disposed on the light-receiving side; and a conductive substrate on which the n-type semiconductor layer is formed; and adjacent to the photoelectrode And a plurality of dye-sensitized solar cells provided with a counter electrode provided.

  The present invention can further improve the light absorption characteristics of organic dyes. The reason why such an effect is obtained is not clear, but for example, the intramolecular charge transfer interaction of an organic dye molecule having an electron accepting site such as a CN group or a rhodanine molecular structure is at least one of a semiconductor and a conductor. It is presumed that the change is caused by the interaction with a metal-containing material (for example, Cu-based material such as CuI), and the light absorption characteristics of the organic dye molecules are expanded to the long wavelength side. In dye-sensitized solar cells, metal-containing materials (for example, Cu-based materials) function as solid electrolytes, so there is no need to use electrolytes, which can further suppress liquid leakage and electrolyte alteration. Thus, the durability can be improved and the photoelectric conversion characteristics can be further improved. In addition, since the light absorption characteristics of organic dyes are further improved, the photoelectric conversion characteristics can be further improved as compared with conventional dye-sensitized solar cells using a metal complex such as Ru and a solid electrolyte. Inferred.

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 the pigment | dyes 1-6 which are an example of the organic pigment | dye molecule | numerator which has CN group. Explanatory drawing of the pigment | dyes 7-9 which is an example of the organic pigment | dye molecule | numerator which has a rhodanine structure. Explanatory drawing of the pigment | dye 10 and 11 which is an example of a pigment | dye. The measurement result of the absorption spectrum of the composite_body | complex of Example 1. FIG. The measurement result of the absorption spectrum of the composite_body | complex of Example 2. FIG. The measurement result of the absorption spectrum of the composite_body | complex of Example 3. FIG. The measurement result of the absorption spectrum of the composite_body | complex of Example 4. FIG. The measurement result of the absorption spectrum of the composite_body | complex of Example 5. FIG. The measurement result of the absorption spectrum of the composite_body | complex of Example 6. FIG. The measurement result of the absorption spectrum of the composite_body | complex of Example 7. FIG. The measurement result of the absorption spectrum of the composite_body | complex of Example 8. FIG. The measurement result of the absorption spectrum of the composite_body | complex of Example 9. FIG. The measurement result of the absorption spectrum of the composite_body | complex of the comparative example 1. The measurement result of the absorption spectrum of the composite_body | complex of the comparative example 2. The measurement result of the absorption spectrum of the photoelectrode of Example 3. The measurement result of the absorption spectrum of the photoelectrode of Example 6. The measurement result of the absorption spectrum of the photoelectrode of Example 7. The measurement result of the absorption spectrum of the photoelectrode of Example 8. The measurement result of the absorption spectrum of the photoelectrode of Example 9. The measurement result of the absorption spectrum of the photoelectrode of Comparative Example 1. The measurement result of the absorption spectrum of the photoelectrode of Comparative Example 2. The IPCE measurement result with respect to the wavelength of the cell of Example 7. The IPCE measurement result with respect to the wavelength of the cell of Example 8. The IPCE measurement result with respect to the wavelength of the cell of Example 9. The IPCE measurement result with respect to the wavelength of the cell of the comparative example 1. The IPCE measurement result with respect to the wavelength of the cell of Comparative Example 2. The current-voltage characteristic measurement result of Examples 7 and 8 and Comparative Example 1.

  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 12 having a transparent conductive film 12 formed on the surface of a transparent substrate 11 through which light is transmitted, and the transparent conductive film 12 via a base layer 22. And a counter electrode 30 provided to the porous semiconductor layer 24 with a solid p-type semiconductor layer 26 and a separator 29 interposed therebetween. The photoelectrode 20 is disposed on the transparent conductive substrate 14, the underlying layer 22 disposed on the transparent conductive film 12 formed separately on the surface opposite to the light receiving surface 13 of the transparent substrate 11, and the underlying layer 22. And a porous semiconductor layer 24 that emits electrons upon receiving light. This dye-sensitized solar cell 40 is configured as a so-called all-solid-type dye-sensitized solar cell in which the photoelectrode 20 and the counter electrode 30 are connected via a solid p-type semiconductor layer 26. As described above, the dye-sensitized solar cell 40 has a configuration capable of generating power without using an electrolyte such as an organic solvent or an ionic liquid.

The transparent conductive substrate 14 is composed of the transparent substrate 11 and the transparent conductive film 12, has light transparency and conductivity, and those used for silicon solar cells and liquid crystal display panels may be used. it can. Specific examples include fluorine-doped SnO ₂ coated glass, ITO coated glass, ZnO: Al coated glass, and antimony-doped tin oxide (SnO ₂ —Sb). 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, provided 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 underlayer 22 is a layer that suppresses or prevents leakage current (reverse electron transfer) from the transparent conductive substrate 14 to the solid p-type semiconductor layer 26. For example, a light-transmitting and conductive material is preferable. In addition, n-type semiconductors such as titanium oxide, zinc oxide, and tin oxide can be used, and among these, titanium oxide is more preferable. This is because titanium oxide suppresses and prevents leakage current and easily allows electrons to flow from the porous semiconductor layer 24 to the transparent conductive substrate 14. The underlayer 22 is preferably made of a denser material than the porous semiconductor layer 24. Even if the base layer 22 is not formed, the base layer 22 may be omitted because it functions sufficiently as the dye-sensitized solar cell 40.

The porous semiconductor layer 24 includes a composite 28 including an organic dye molecule having an electron accepting site including at least one of S and N, and a metal-containing material that is at least one of a semiconductor and a conductor, and the composite The n-type semiconductor layer to which the organic dye molecules of the body 28 are adsorbed is formed. That is, the porous semiconductor layer 24 is a layer in which the composite 28 and the n-type semiconductor layer are combined. The organic dye molecules are dyes that emit electrons upon receiving light, as will be described in detail later. Examples of the metal-containing material include Cu, Ag, Au, Ni, Co, Cr, Pt, and Pd. Among these, a Cu containing at least one of a semiconductor containing Cu and a conductor containing Cu. More preferably, it is a system material. Examples of the Cu-based material include one or more of CuI, CuSCN, CuO, Cu ₂ O, and Cu, and among these, CuI is more preferable because it easily interacts with organic dye molecules. Hereinafter, for convenience of explanation, a Cu-based material will be used as the metal-containing material. 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. The organic dye may be adsorbed on the surface of the 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 an organic dye-containing solution onto the n-type semiconductor layer and drying it, or dipping in a dye solution and drying After that, a Cu-based material solution can be dropped and dried. Here, the photoelectrode 20 is a composite 28 in which an organic dye contained in the porous semiconductor layer 24 interacts with a Cu-based material. It is considered that this interaction expands the light absorption characteristics of the organic dye molecules to the longer wavelength side, and as a result, higher photoelectric conversion characteristics can be obtained. Although this complex 28 is considered to be a complex of organic dye molecules and Cu-based material, the form may be, for example, a complex. The complex 28, particularly the organic dye molecule, will be described in detail below.

The organic dye molecule has an electron accepting site containing at least one of S and N. For example, the organic dye molecule may have a CN group, and preferably has an ethylene structure to which a CN group represented by Formula (1) is bonded. Alternatively, the organic dye molecule may have a rhodanine structure represented by the formula (2). In the formulas (1) and (2), the substituents R ^{1 to} R ⁶ may be the same or different, for example, hydrogen, alkyl group, cycloalkyl group, heterocyclic group, alkenyl group, cycloalkenyl group, Alkynyl group, alkoxy group, alkylthio group, aryl ether group, aryl thioether group, aryl group, heteroaryl group, halogen, cyano group, carbonyl group, carboxyl group, oxycarbonyl group, carbamoyl group, amino group, phosphine oxide group, adjacent It may be selected from a condensed ring formed between the substituent and sulfur. Among these substituents, the alkyl group is, for example, a saturated aliphatic hydrocarbon group such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, or a tert-butyl group. This may or may not have a substituent. There are no particular limitations on the additional substituent when it is substituted, and examples include an alkyl group, an aryl group, a heteroaryl group, and the like, and this point is common to the other substituents. The number of carbon atoms of the substituent such as an alkyl group is not particularly limited, but is usually in the range of 1 to 20 and more preferably 1 to 12 from the viewpoint of ease of production and cost.

FIG. 2 is an explanatory diagram of dyes 1 to 6 which are examples of organic dye molecules having a CN group according to this embodiment, and FIG. 3 is a dye 7 which is an example of organic dye molecules having a rhodanine structure according to this embodiment. It is explanatory drawing of -9. First, organic dye molecules having a CN group will be described (see dyes 1 to 6 in FIG. 2). As for this organic pigment | dye molecule | numerator, it is preferable that the carboxyl group has couple | bonded as shown in Formula (3). For example, the fixation to a metal oxide such as titanium oxide becomes stronger due to the chemical adsorption of the carboxyl group of the dye and the metal oxide, and the efficiency of electron transfer is also increased. Further, in the organic dye molecule, a CN group is bonded to at least one of an aromatic ring containing at least one of N and S and an aromatic ring bonded with at least one of N and S via an ethylene structure. It is more preferable. For example, as an example of an aromatic ring containing at least one of N and S, as shown in the formula (4), one or more thiophene structures (aromatic rings containing S) are bonded to carbon having a double bond of an ethylene structure. Examples include a bonded structure (see dyes 1 to 3 in FIG. 2). In the formula (4), the substituent R ¹ in the formula (1) has a thiophene structure, but any of the substituents R ^{1 to} R ³ may have a thiophene structure (hereinafter referred to as “substituent R ^1”). The same). In this thiophene structure, n is preferably 1 or more and 5 or less. The substituent R ^{8 serving as} the terminal of the thiophene structure may be, for example, a substituent represented by the formula (5) or a substituent represented by the formula (6). The substituent R ⁷ may be, for example, any one of hydrogen and an alkyl group having 1 to 20 carbon atoms. Examples of the aromatic ring to which at least one of N and S are bonded include a substituent having an aromatic ring to which N is bonded as shown in formulas (5) to (7) (Dye 1 in FIG. 2). ~ 5). The organic dye molecule having a CN group may have a structure in which two or more ethylene structures are linked, or a conjugated structure. That is, it is preferable that at least one of the substituents R ¹ and R ^{2 in} the formula (1) contains an ethylene structure. At this time, it is preferable that a substituent represented by the formula (7) is bonded to at least one terminal of the substituents R ¹ and R ² of the formula (1) (see dyes 4 and 5 in FIG. 2). Adopting any one of these configurations is preferable because interaction with the Cu-based material of the solid p-type semiconductor layer 26 is induced, and the light absorption characteristics of the organic dye molecules are easily improved.

Next, organic dye molecules having a rhodanine structure will be described (see dyes 1 to 3 in FIG. 3). This organic dye molecule is represented by the formula (2) wherein the substituent R ⁴ bonded to N of the rhodanine structure is an alkyl group having 3 to 20 carbon atoms and a carboxyl group bonded to a carbon chain having 1 to 20 carbon atoms. Any one of them is preferable. When the substituent R ⁴ is an alkyl group, it is preferable that the number of carbon atoms is 3 or more, which is chemically more stable, and the number of carbon atoms of 20 or less is preferable because an organic dye molecule can be easily produced. The number of carbon atoms of the substituent R ⁴ is more preferably 5 or more and 12 or less. Further, in the organic dye molecule, it is preferable that at least one of the substituents R ⁵ and R ⁶ of the rhodanine structure further has a similar rhodanine structure. For example, examples of the substituent R ⁵ having a rhodanine structure include those represented by formula (8). Further, the organic dye molecule has an aromatic ring in which at least one of the substituents R ⁴ , R ⁵ and R ⁶ having a rhodanine structure includes at least one of N and S, and an aromatic in which at least one of N and S is bonded. It is preferable that at least one of the rings is included. Examples of the aromatic ring in which at least one of N and S are bonded include those represented by the formula (8). The organic dye molecule represented by the formula (8) has a structure in which the substituent R ⁶ is S, and an acetic acid group is bonded to N of the rhodanine structure in the substituent R ⁵ . Among these configurations, it is preferable to employ any one of the modes because an interaction between the organic dye molecule and the Cu-based material is induced, and the light absorption characteristics of the organic dye molecule are easily improved.

The solid p-type semiconductor layer 26 may be a layer formed of a semiconductor containing Cu. As the semiconductor containing Cu, for example, one or more of CuI, CuSCN, CuO, and Cu ₂ O are preferably used, and CuI is more preferably used, like the Cu-based material. Alternatively, the solid p-type semiconductor layer 26 may be a conductor layer formed of a conductor containing Cu. The solid p-type semiconductor layer 26 may be made of a material different from the Cu-based material of the composite 28, but is preferably made of the same material because it is easy to produce.

  The separator 29 is formed in an I-shaped cross section so as to be adjacent to one side surface of the photoelectrode 20 on which the base layer 22, the porous semiconductor layer 24 and the solid p-type semiconductor layer 26 are laminated. One end of the separator 29 is in contact with the groove 18 on the transparent conductive substrate 14. Thereby, the direct contact with the photoelectrode 20 and the counter electrode 30 is avoided. The separator 29 is made of an insulating material, and may be formed of, for example, glass beads, silicon dioxide (silica), rutile titanium oxide, or the like. The separator 29 is preferably an insulator in which silica particles are sintered. Silica particles are preferable for the separator because they have a low refractive index, low light scattering, and good transparency. The separator 29 preferably has an average particle size of 5 to 200 nm from the viewpoint of ensuring good transparency.

  The counter electrode 30 is formed in an L-shaped cross section so as to contact the outer surface of the separator 29 and the back surface 27 of the solid p-type semiconductor layer 26. The counter electrode 30 has one end connected to the back surface of the solid p-type semiconductor layer 26 and the other end 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 faces the photoelectrode 20 at a predetermined interval. The counter electrode 30 is not particularly limited as long as it has conductivity and bondability to the solid p-type semiconductor layer 26, and examples thereof include Pt, Au, and carbon. Among these, carbon is preferable.

  The sealing material 32 can be used without particular limitation as long as it is an insulating member. As the sealing material 32, for example, a thermoplastic resin film such as polyethylene or an epoxy adhesive 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 this dye-sensitized solar cell 40 is irradiated with light from the light-receiving surface 13 side of the transparent substrate 11, the light is transmitted through the light-receiving surface 15 of the transparent conductive film 12 and the light-receiving surface 23 of the base layer 22 into the porous semiconductor. Reaching the layer 24, the organic dye absorbs light and generates electrons and holes. Holes move from the porous semiconductor layer 24 to the solid p-type semiconductor layer 26. On the other hand, 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 holes, and the power generation action of the battery can be obtained. In this dye-sensitized solar cell module 10, the interaction between the organic dye and the Cu-based material is induced in the composite 28, and the light absorption characteristics of the organic dye molecules are further improved, resulting in higher photoelectric conversion characteristics. Show.

The dye-sensitized solar cell module 10 is manufactured through a substrate manufacturing process, a porous semiconductor layer forming process, a p-type semiconductor layer forming process, a separator forming process, a counter electrode forming process, and a protective member forming process as a manufacturing method. Can do. In the substrate manufacturing process, the transparent conductive film 12 is formed on the transparent substrate 11 while forming the grooves 18 between the plurality of transparent conductive films 12. In the porous semiconductor layer forming step, an n-type semiconductor layer is formed on the transparent conductive film 12 via the base layer 22, and an organic dye is adsorbed to the n-type semiconductor layer, and then a Cu-based material is added to form a composite. 28 is formed, and the porous semiconductor layer 24 is formed. Here, as the organic dye, the organic dye molecule having an electron accepting site including at least one of S and N described above, for example, one having a CN group or a rhodanine structure is used. Further, porous titanium oxide is used as the n-type semiconductor layer. In addition, a semiconductor containing Cu (for example, any one or more of CuI, CuSCN, CuO, and Cu ₂ O) is used as the Cu-based material. When the porous semiconductor layer 24 is formed, an organic dye molecule having an electron accepting site containing at least one of S and N contained in the porous semiconductor layer 24 interacts with a Cu-based material, and the organic dye It is considered that the light absorption characteristics of the molecules expand to the long wavelength side. This long wavelength shift is considered to improve the photoelectric conversion characteristics of the dye-sensitized solar cell 40 by expanding the wavelength region that can be used for photoelectric conversion. Next, in the p-type semiconductor layer formation step, the solid p-type semiconductor layer 26 may be formed by supplying a solid p-type semiconductor to the back surface 25 of the porous semiconductor layer 24 and then drying it. Here, a semiconductor containing Cu is used as the solid p-type semiconductor. Subsequently, in the separator forming step, a separator 29 is formed on the side surface of the photoelectrode 20 in alignment with the groove 18. In the counter electrode forming step, the counter electrode 30 is formed in contact with the separator 29 and the solid p-type semiconductor layer 26. The counter electrode 30 may be carbon, for example. In the protective member forming step, the sealing material 32 is formed so as to cover each cell, and the protective member 34 is formed on the sealing material 32. In this manner, the dye-sensitized solar cell 40 and the dye-sensitized solar cell module 10 with improved power generation characteristics can be produced.

  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 dye-sensitized solar cell module 10 is not particularly limited thereto, and the dye-sensitized solar cell 40 may be used. The photoelectrode 20 may be formed of a semiconductor layer and a Cu-based material, or may be a composite 28 containing an organic dye and a Cu-based material. When the dye-sensitized solar cell 40 is used alone, the counter electrode 30 may be formed in a flat plate shape instead of an L shape.

  Hereinafter, examples in which the composite, the photoelectrode, and the dye-sensitized solar cell of the present invention were specifically manufactured will be described as examples.

[Evaluation of light absorption characteristics of composite]
The composite of the present invention was prepared using CuI as the solid p-type semiconductor layer and dyes 1 to 11 (see FIGS. 2 to 4) as organic dye molecules, and the light absorption spectrum was examined. Here, the dye alone, CuI only, and the complex of CuI and dye are measured, the absorption spectrum of CuI is subtracted from the absorption spectrum of the complex, and the absorption spectrum obtained only with the dye and the dye contained in the complex The properties were evaluated by comparing with the absorption spectrum obtained in (1).
The absorption spectrum was measured with a spectrophotometer (U-3400 manufactured by Hitachi, Ltd.) in a wavelength region of 290 nm to 900 nm.

[Examples 1 to 9 (complex)]
The complex was prepared by mixing the dye and CuI in acetonitrile (AcCN) as a solvent so that the dye was 5 μM and CuI was 30 mM. The composites produced using the dyes 1 to 9 shown in FIGS. 2 and 3 were used as composites of Examples 1 to 9, respectively.

[Comparative Examples 1 and 2 (composite)]
The Ru complex shown in FIG. The dye 10 and CuI were mixed with acetonitrile (AcCN) so that the dye 10 was 10 μM and CuI was 30 mM, and the resultant was used as the composite of Comparative Example 1. An organic dye molecule containing S and N but having no electron accepting site shown in FIG. The dye and CuI were mixed with acetonitrile (AcCN) so that the dye 11 was 5 μM and CuI was 30 mM, and the resultant was used as the composite of Comparative Example 2.

(Experimental result of complex)
The measurement results of the absorption spectra of the composites of Examples 1 to 9 are shown in FIGS. 5 to 13, and the measurement results of the absorption spectra of Comparative Examples 1 and 2 are shown in FIGS. First, in Examples 1 to 9, it was predicted that the color development of the solution changed at the time when the dye and CuI were mixed, and some kind of interaction occurred in the production of the composite. On the other hand, in Comparative Examples 1 and 2, there was no change in the color of the solution. As shown in FIG. 14, in the dye 10 of Comparative Example 10, the peak of the absorption spectrum shifted to the short wavelength side, that is, shifted in a disadvantageous direction as a dye-sensitized solar cell. This is because, in the case of a Ru complex having an SCN group such as the dye 10, MLCT (Metal to Ligand Charge Transfer) between Ru (Metal) -ligand (Ligand) is determined by S and CuI of the ligand SCN group. It was inferred that it changed due to the interaction of and shifted to the short wavelength side. Moreover, as shown in FIG. 15, in the pigment | dye 11 of the comparative example 11, there was no change in the peak position of an absorption spectrum. For this reason, it was guessed that there was no clear interaction between the pigment | dye 11 and CuI. On the other hand, in the composites of dyes 1 to 9 in Examples 1 to 9, the absorption spectrum peak shifted to the longer wavelength side, that is, shifted in an advantageous direction as a dye-sensitized solar cell. Thus, the interaction was clearly recognized between the pigment | dyes 1-9 and CuI.

[Evaluation of light absorption characteristics of photoelectrode]
On the TCO glass substrate, a porous titanium oxide film is applied as an n-type semiconductor layer of the porous semiconductor layer 24 by a screen printing method, dried at 150 ° C., and then heated to 450 ° C. in an electric furnace. A membrane substrate was prepared. Next, a dye solution containing each of the dyes 1 to 11 was prepared. A mixed solution prepared by mixing acetonitrile and tert-butyl alcohol in which 0.4 mM of the above-described dyes 1, 2, 4 to 9, 11 was dissolved was prepared and used as each dye solution. In addition, toluene in which 0.4 mM of the above-described dye 3 was dissolved was prepared and used as a dye solution. Moreover, the mixed solution which mixed acetonitrile and tert- butyl alcohol which melt | dissolved 0.3 mM of the pigment | dyes 10 mentioned above was prepared, and it was set as the pigment | dye solution. Subsequently, the titanium oxide film substrate was respectively immersed in the dye solutions containing the prepared dyes 1 to 11 and allowed to stand for 15 hours under a temperature condition of 25 ° C. Thus, the board | substrate which adsorb | sucked the pigment | dyes 1-11 to the titanium oxide film board | substrate was each produced. Subsequently, CuI was saturated with acetonitrile, and 1-methyl 3-ethylimidazolium thiocyanate (EMISCN) was added to prepare a CuI solution. The dye-adsorbed titanium oxide film substrate obtained above was placed on a hot plate at 40 ° C. to 120 ° C. so that the titanium oxide film was on top. 10 μL of the prepared CuI solution was dropped on the dye-adsorbed titanium oxide film to form a complex with the dye in the titanium oxide film adsorbed by CuI, and the solvent contained in the CuI solution was evaporated to fill the CuI. . In this way, a photoelectrode was produced. Those obtained using the dyes 1 to 9 were used as the photoelectrodes of Examples 1 to 9, respectively, and those obtained using the dyes 10 and 11 were used as the photoelectrodes of Comparative Examples 1 and 2, respectively. Here, only TiO _2, those containing TiO ₂ and a dye, the optical electrode comprising TiO ₂ and dye and CuI, the three measures, the absorption spectrum and TiO ₂ and a dye of those containing TiO ₂ and dye Was compared with the absorption spectrum of a photoelectrode containing CuI, and its characteristics were evaluated.

(Photoelectrode experiment results)
The measurement results of the absorption spectra of the photoelectrodes of Examples 3 and 6 to 9 are shown in FIGS. 16 to 20, and the measurement results of the absorption spectra of Comparative Examples 1 and 2 are shown in FIGS. As shown in FIG. 21, in the optical electrode using a dye 10 in Comparative Example 10, relative to those containing TiO ₂ and a dye, the absorption spectrum of the photoelectrode containing TiO ₂ and a dye and CuI are short wavelength side That is, it shifted in a disadvantageous direction as a dye-sensitized solar cell. Moreover, as shown in FIG. 22, in the photoelectrode using the pigment | dye 11 of the comparative example 11, there was no change in the peak position of the absorption spectrum of a photoelectrode. In contrast, in Example 3,6～9 shown in FIG. 16 to 20 in the photoelectrode of a dye, with respect to those containing TiO ₂ and a dye, the photoelectrode including the TiO ₂ and the dye and CuI The peak of the absorption spectrum was shifted to the longer wavelength side, that is, shifted in an advantageous direction as a dye-sensitized solar cell. These results support the results with the complex. In the lower part of FIG. 17, the spectrum obtained by subtracting the measurement result of TiO ₂ from the measurement result of (TiO ₂ / dye) in Example 6 and the measurement result of (TiO ₂ / dye / CuI) of TiO ₂ are shown. The spectrum obtained by subtracting the measurement results is shown. Since the light transmittance changes due to the addition of CuI, the absolute value of the amount of absorption cannot be compared in FIG. 17, but the latter is shifted to the longer wavelength side for the peak position of the absorption spectrum. . From these results, it was found that in the photoelectrodes of Examples 3 and 6 to 9, the photoelectric conversion characteristics can be further improved by combining TiO ₂ , a dye, and CuI to form a photoelectrode. The same applies to the photoelectrodes of the other examples.

[Dye-sensitized solar cell IPCE characteristic and solar cell characteristic evaluation]
Similar to the production of the photoelectrode, a titanium oxide film substrate, a dye solution, and a CuI solution are prepared, and the titanium oxide film is placed on the obtained dye-adsorbed titanium oxide film substrate on a hot plate at 40 ° C. to 120 ° C. Left to stand. Next, 500 μL of the prepared CuI solution is dropped on the dye-adsorbed titanium oxide film to form a complex with the dye in the titanium oxide film adsorbed by CuI, and the CuI solution is evaporated by evaporating the solvent contained in the CuI solution. A CuI layer (solid p-type semiconductor layer) was also formed on the titanium oxide film. And the Pt thin film as a counter electrode was arrange | positioned on this CuI layer, and the dye-sensitized solar cell was produced. First, the characteristics of the dye-sensitized solar cell of the present invention using CuI with respect to the dye-sensitized solar cell using the iodine redox electrolyte were examined. For iodine redox, a γ-butyrolactone solution in which iodine and 1,2-dimethyl-3-propylimidazolium iodide were dissolved was used. The evaluation was performed using the IPCE value and the short-circuit current density J _SC value. The short-circuit current density J _SC value of the dye-sensitized solar cell using the iodine redox reaction to "1" to determine the short-circuit current density J _SC value of the dye-sensitized solar cells of Examples and Comparative Examples as a ratio. Here, the dye-sensitized solar cells of Examples 7 and 8 and Comparative Examples 1 and 2 were evaluated. Moreover, the pigment | dye was compared with the characteristic of the pigment | dye sensitized solar cell at the time of using CuI. Here, the short-circuit current density J _SC value, the open circuit voltage V _OC , and the conversion efficiency η of the dye-sensitized solar cell using the dye 10 of Comparative Example 1 are set to “1” and compared with Examples 7 and 8. It was. IPCE refers to a value obtained by calculating the photoelectric conversion efficiency (external quantum yield) per monochromatic light from the number of electrons obtained with respect to the irradiation light quantity (or the number of photons).

(Experimental result of dye-sensitized solar cell)
The IPCE measurement results with respect to the wavelengths of the cells of Examples 7 to 9 are shown in FIGS. 23 to 25, the IPCE measurement results with respect to the wavelengths of the cells of Comparative Examples 1 and 2 are shown in FIGS. The current-voltage characteristic measurement results of Examples 7 and 8 and Comparative Example 1 are shown in FIG. Further, the short-circuit current density ratio of the CuI electrolyte to the iodine redox electrolyte is shown in Table 1, and the short-circuit current density ratio, open-circuit voltage ratio, and conversion efficiency ratio of Examples 7 and 8 relative to Comparative Example 1 are shown in Table 2. As shown in FIG. 26, in the cell using the dye 10 of Comparative Example 10, the IPCE spectrum was shifted to the short wavelength side as compared with the cell using the iodine redox electrolyte, that is, as a dye-sensitized solar cell. Shifted in a disadvantageous direction. Moreover, as shown in FIG. 27, in the cell using the pigment | dye 11 of the comparative example 11, there was no change in the peak position of an IPCE spectrum. On the other hand, in the cells using the composites of Examples 7 to 9, the absorption spectrum of the cell containing the composites was shifted to the longer wavelength side compared to the cells using the iodine redox electrolyte solution, that is, the dye increase. It shifted to an advantageous direction as a sensitive solar cell. These results support the results with the complex. As shown in Table 1, the ratio of the short-circuit current density (J _SC ) of the cell using the composite to the short-circuit current density (J _SC ) of the cell using iodine redox electrolyte was 0. In contrast to the low value of 8, the cells of Examples 7 and 8 showed high values of 1.7 and 1.2. Thus, it was found that the photoelectric conversion characteristics can be further improved in the cells of Examples 7 to 9. The same applies to the cells of the other examples. Further, as shown in Table 2 and FIG. 28, the short circuit current density J _SC value of the cell when using CuI was found to be higher than that of the dye 10 of Comparative Example 1 in Examples 7 and 8 due to the above-mentioned IPCE improvement effect. The dye-sensitized solar cells using the dyes 7 and 8 were increased. In addition, regarding the open-circuit voltage V _OC of the cell when CuI is used, it is presumed that the dyes 7 and 8 have an advantageous effect of controlling the interface between titanium oxide and CuI as compared with the dye 10. The dye-sensitized solar cell using the dyes 7 and 8 of Examples 7 and 8 increased more than the dye 10 of Example 1. It was also found that the cell conversion efficiency η when using CuI was improved in the dye-sensitized solar cells of Examples 7 and 8 as compared with Comparative Example 1.

  The present invention can be suitably used for a dye-sensitized solar cell and a dye-sensitized solar cell module.

  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, 22 Underlayer, 23 Light-receiving surface, 24 Porous semiconductor layer, 25 Back surface, 26 Solid p-type semiconductor layer, 27 Back surface, 28 Composite, 29 Separator, 30 Counter electrode, 32 Sealing material, 34 Protection member, 40 Dye-sensitized type Solar cell.

Claims (15)

An organic dye molecule having an electron accepting site containing at least one of S and N;
A metal-containing material that is at least one of a semiconductor and a conductor containing at least one of Cu, Ag, Au, Ni, Co, Cr, Pt, and Pd ,
The organic dye molecule is a compound having any one of the structures represented by formulas (1) to (3) (provided that the substituent of the compound of formula (1) has the structure of formula (4)). even if well, the end of the substituents of the compounds of formula (3), equation (5) may have any structure of (6)), multiple combined.
  The composite according to claim 1, wherein the metal-containing material is a Cu-based material including at least one of a semiconductor including Cu and a conductor including Cu. The composite according to claim 2, wherein the Cu-based material includes one or more of CuI, CuSCN, CuO, Cu ₂ O, and Cu. The organic dye molecule includes an alkyl group having 3 to 20 carbon atoms and a carboxyl group having 1 to 20 carbon atoms and a substituent R ⁴ bonded to N of the rhodanine structure represented by the formula (2). The complex according to any one of claims 1 to 3, which is any one of the above. The organic dye molecules, the rhodanine at least one of the substituents R ⁵ and R ⁶ of the structure further comprises the rhodanine structure composite according to any one of claims 1 to 4. The organic dye molecule includes an aromatic ring in which at least one of the substituents R ⁴ , R ⁵ and R ⁶ of the rhodanine structure includes at least one of N and S, and an aromatic in which at least one of N and S is bonded. The complex according to any one of claims 1 to 5 , comprising at least one of rings. A photoelectrode used in a dye-sensitized solar cell,
The composite according to any one of claims 1 to 6 , an n-type semiconductor layer on which organic dye molecules of the composite are adsorbed, a conductive substrate on which the n-type semiconductor layer is formed, A photoelectrode. The photoelectrode according to claim 7 , wherein the n-type semiconductor layer contains at least one of titanium oxide, tin oxide, zinc oxide, cadmium sulfide, and zinc sulfide. The photoelectrode according to claim 8 , wherein the n-type semiconductor layer is titanium oxide. A transparent substrate through which light is transmitted and a transparent conductive film is formed;
An n-type semiconductor layer provided adjacent to the transparent substrate and adsorbed with the complex according to any one of claims 1 to 6 and an organic dye molecule of the complex and the n-type semiconductor layer are formed. A photoelectrode comprising a conductive substrate,
A counter electrode provided adjacent to the photoelectrode;
A dye-sensitized solar cell comprising: The dye-sensitized solar cell according to claim 10 , wherein the n-type semiconductor layer includes at least one of titanium oxide, tin oxide, zinc oxide, cadmium sulfide, and zinc sulfide. The dye-sensitized solar cell according to claim 11 , wherein the n-type semiconductor layer is titanium oxide. A transparent substrate on which light is transmitted and a transparent conductive film is formed, and provided adjacent to the transparent substrate. The complex according to any one of claims 1 to 6 and an organic dye molecule of the complex Dye-sensitized type comprising a photoelectrode comprising an adsorbing n-type semiconductor layer and a conductive substrate on which the n-type semiconductor layer is formed, and a counter electrode provided adjacent to the photoelectrode A dye-sensitized solar cell module comprising a plurality of solar cells. The dye-sensitized solar cell module according to claim 13 , wherein the n-type semiconductor layer includes at least one of titanium oxide, tin oxide, zinc oxide, cadmium sulfide, and zinc sulfide. The dye-sensitized solar cell module according to claim 14 , wherein the n-type semiconductor layer is titanium oxide.