JP6539146B2 - Photoelectric conversion element - Google Patents

Description

  The present invention relates to a photoelectric conversion element.

  As a photoelectric conversion element, a photoelectric conversion element using a dye is attracting attention because it is inexpensive and high photoelectric conversion efficiency can be obtained, and various developments have been made with respect to a photoelectric conversion element using such a dye.

  A photoelectric conversion element using a dye generally includes a photoelectric conversion cell, and the photoelectric conversion cell is provided on a transparent conductive substrate, a counter substrate facing the conductive substrate, a conductive substrate or a counter substrate, An oxide semiconductor layer on which a dye is supported, an annular sealing portion for connecting the conductive substrate and the counter substrate, and an electrolyte which is disposed between the conductive substrate and the counter substrate and contains a redox couple. Have. However, in such a photoelectric conversion cell, when the photoelectric conversion cell is viewed from the light incident side of the conductive substrate, an internal structure such as a color or a shape may be visible around the oxide semiconductor layer through the sealing portion. The That is, there were cases where the appearance was not good.

  Therefore, in the photoelectric conversion element, by providing a colored insulating material between the sealing portion and the conductive substrate, an internal structure such as color or shape can be seen around the oxide semiconductor layer through the sealing portion. It has been proposed to impart excellent durability to a photoelectric conversion element while suppressing the above and achieving a good appearance (see Patent Document 1 below).

WO 2015/098914

  However, the photoelectric conversion element described in Patent Document 1 has the following problems.

  That is, although the photoelectric conversion element described in Patent Document 1 can realize a good appearance, it still has room for improvement in terms of durability over a long period of time.

  This invention is made in view of the said situation, and it aims at providing the photoelectric conversion element which has the outstanding durability, maintaining a favorable external appearance.

  The present inventors diligently studied to solve the above-mentioned problems. As a result, the present inventors have found that the above-mentioned problems can be solved by the following invention.

  That is, the present invention has a conductive substrate having at least one photoelectric conversion cell, the photoelectric conversion cell having a transparent substrate and a transparent conductive layer provided on the transparent substrate, and facing the conductive substrate. A counter substrate, an oxide semiconductor layer provided on the conductive substrate or the counter substrate, an electrolyte disposed between the conductive substrate and the counter substrate, the conductive substrate and the counter substrate are joined Ring-shaped sealing portion, an insulating material provided between the conductive substrate and the sealing portion, which is colored, and a surface of the insulating material, between the insulating material and the electrolyte And a protective layer having a covering portion provided on the insulating layer, wherein the insulating material contains a coloring material, and the content of the coloring material in the protective layer is smaller than the content of the coloring material in the insulating material. It is a photoelectric conversion element.

  According to this photoelectric conversion element, the protective layer has a covering portion provided on the surface of the insulating material and between the insulating material and the electrolyte, and the coloring material content in the protective layer is the insulating material The content of the coloring material in the electrolyte can be reduced as compared with the case where the protective layer is not provided because the content of the coloring material is smaller than the content of the coloring material in the inside. For this reason, according to the photoelectric conversion element of this invention, the fall of the photoelectric conversion characteristic by mixing of a coloring material can be suppressed, and it becomes possible to have the outstanding durability. Also, since it is not necessary to remove the coloring material from the insulating material, a good appearance can be maintained.

  In the photoelectric conversion device, the protective layer preferably contains no coloring material.

  In this case, it is possible to prevent the colorant from entering the electrolyte. For this reason, according to the photoelectric conversion element of the present invention, the deterioration of the photoelectric conversion characteristic due to the mixing of the coloring material can be sufficiently suppressed, and it is possible to have more excellent durability.

  In the photoelectric conversion element, preferably, the protective layer is interposed between the sealing portion and the insulating material.

  In this case, the protective layer can prevent the coloring material in the insulating material from migrating to the interface between the sealing portion and the insulating material, and mixing in the electrolyte through the interface.

  In the photoelectric conversion element, the coloring material is made of, for example, an oxide of a transition metal.

  The photoelectric conversion device is useful when the redox couple contains a halogen atom.

  If the colorant is composed of a transition metal oxide and the redox couple in the electrolyte contains a halogen atom, there is a possibility that the colorant and the redox couple in the electrolyte react in some way. In that respect, in the present invention, since the protective layer is provided on the surface of the insulating material, the amount of the colorant mixed in the electrolyte can be reduced. For this reason, it is possible to reduce the amount of colorant that reacts with the redox couple in the electrolyte.

  In the present invention, "colorant" refers to a substance having an absorption peak in the visible light wavelength range. Here, the wavelength range of visible light refers to a wavelength range of 380 to 800 nm.

  Moreover, in this invention, the unit of "content rate of a coloring material" is mass%.

  Furthermore, in the present invention, "containing no colorant" means that the content of the colorant is 0.4% by mass or less.

  According to the present invention, a photoelectric conversion element having excellent durability while maintaining a good appearance is provided.

It is a cut surface end view which shows 1st Embodiment of the photoelectric conversion element of this invention. It is a cut surface end view which shows 2nd Embodiment of the photoelectric conversion element of this invention.

  Hereinafter, a preferred embodiment of the photoelectric conversion element of the present invention will be described in detail with reference to FIG. FIG. 1 is a sectional end view showing a first embodiment of the photoelectric conversion element of the present invention.

  As shown in FIG. 1, the photoelectric conversion element 100 has a plurality (four in FIG. 1) of photoelectric conversion cells (hereinafter simply referred to as “cells”) 50. The plurality of cells 50 are connected in series.

  Each of the plurality of cells 50 includes a conductive substrate 15, an oxide semiconductor layer 13 provided on the conductive substrate 15, a counter substrate 20 facing the conductive substrate 15, a conductive substrate 15, and a counter substrate 20. Between the conductive substrate 15 and the sealing portion 30A, the electrolyte 40 containing a redox couple, the annular sealing portion 30A joining the conductive substrate 15 and the counter substrate 20, and , And a protective layer 35 for protecting the insulating material 34 from the electrolyte 40. The oxide semiconductor layer 13 is disposed inside the annular sealing portion 30A. Further, a dye is supported on the oxide semiconductor layer 13. The electrolyte 40 is surrounded by an annular seal 30A.

  The counter substrate 20 includes a metal substrate 21 and a catalyst layer 22 provided on the conductive substrate 15 side of the metal substrate 21 to promote a catalytic reaction. In the two adjacent cells 50, the opposing substrates 20 are separated from each other.

  The conductive substrate 15 has a transparent substrate 11 and a transparent conductive layer 12 provided on the transparent substrate 11. The transparent substrate 11 is used as a common transparent substrate of the plurality of cells 50.

  The transparent conductive layers 12 of the plurality of cells 50 are provided in a mutually insulated state. That is, the transparent conductive layers 12 of two adjacent cells 50 are arranged via the grooves 90.

  The sealing portion 30A is provided, for example, between the conductive substrate 15 and the counter substrate 20. In addition, although adjacent sealing part 30A is integrated as shown in FIG. 1, and it comprises the integral sealing part, it does not need to be integrated.

  The insulating material 34 is made of an insulating material, and is provided so as to enter the groove 90 between the adjacent transparent conductive layers 12 and to straddle the adjacent transparent conductive layers 12.

  The protective layer 35 has a covering portion 35 a provided on the surface of the insulating material 34 and between the insulating material 34 and the electrolyte 40. Specifically, the protective layer 35 covers the entire surface of the insulating material 34 other than the portions in contact with the transparent substrate 11 and the transparent conductive layer 12. That is, the protective layer 35 is interposed not only between the insulating material 34 and the electrolyte 40 but also between the insulating material 34 and the sealing portion 30A. Here, the protective layer 35 is configured of a covering portion 35a, a sandwiching portion 35b sandwiched between the insulating material 34 and the sealing portion 30A, and an exposed portion 35c exposed to the covering portion 35a or the air. Specifically, the protective layer 35 covering a portion of the insulating material 34 which is in the groove 90 between the transparent conductive layers 12 of the adjacent cells 50 is a covering portion 35a, a sandwiching portion 35b, a covering portion 35a, and the like. The protective layer 35 covering the portion of the insulating material 34 which does not enter the groove 90 between the transparent conductive layers 12 of the adjacent cells 50 is a cover portion 35a, a sandwiching portion 35b, and an exposed portion 35c. It is configured.

  Then, the content of the coloring material in the protective layer 35 is smaller than the content of the coloring material in the insulating material 34.

  According to this photoelectric conversion element 100, the protective layer 35 has the covering portion 35 a provided on the surface of the insulating material 34 and between the insulating material 34 and the electrolyte 40, and coloring in the protective layer 35. Since the content rate of the material is smaller than the content rate of the coloring material in the insulating material 34, the amount of the coloring material entering the electrolyte 40 can be reduced as compared with the case where the protective layer 35 is not provided. For this reason, according to the photoelectric conversion element 100, the deterioration of the photoelectric conversion characteristic due to the mixing of the coloring material can be suppressed, and it is possible to have excellent durability. Moreover, according to the photoelectric conversion element 100, since it is not necessary to remove a coloring material from the insulating material 34, a favorable external appearance can also be maintained.

  Further, in the photoelectric conversion element 100, since the protective layer 35 (specifically, the sandwiching portion 35b) is interposed between the sealing portion 30A and the insulating material 34, the coloring material in the insulating material 34 is the sealing portion The protective layer 35 can prevent the transition to the interface between 30 A and the insulating material 34 and the mixing into the electrolyte 40 through the interface.

  Next, the insulating material 34, the protective layer 35, the conductive substrate 15, the counter substrate 20, the oxide semiconductor layer, the dye, the sealing portion 30A, and the electrolyte 40 will be described in detail.

(Insulating material)
The insulating material 34 may be made of an insulating material and be colored.

Since the insulating material 34 is colored, the color of the insulating material 34 can be made close to the color of the oxide semiconductor layer 13, and a good appearance can be maintained. Here, "being colored" refers to L ^* of ^L * ^a * ^{b *} color space of the insulating material 34 is less than 70. Here, L ^* is defined by the following equation, where x is a spectral reflectance of 700 nm with respect to CIE D65 standard light, y is 546.1 nm, and z is 435.8 nm.
L ^* = 116 * (0.2126z + 0.7152y + 0.0722x) ¹ /3-16

The color of the insulating material 34 is not particularly limited, and various colors can be used depending on the purpose. For example, in the case where characters or design are not displayed on the conductive substrate 15, the color of the insulating material 34 may be the same as that of the oxide semiconductor layer 13. Here, the color of the same system means a color in which the difference between L ^* , a ^* and b ^{* in} the L ^* a ^* b ^* color space is within ± 5.

  The insulating material 34 is preferably a light transmission preventing layer that prevents the transmission of light. Here, the “light transmission preventing layer” refers to a layer having an average light transmittance of 50% or less in the visible light wavelength region. Moreover, the wavelength range of visible light means the wavelength range of 380-800 nm.

  Examples of the insulating material include inorganic insulating materials such as glass frit, thermosetting resins such as polyimide resin, and thermoplastic resins. Among them, it is preferable to use an inorganic insulating material such as glass frit or a thermosetting resin. In this case, even if the sealing portion 30A comes to have fluidity at high temperature, the insulating material 34 is less likely to be fluidized even at high temperature than when it is made of thermoplastic resin. Therefore, the contact between the conductive substrate 15 and the counter substrate 20 can be sufficiently suppressed, and the short circuit between the conductive substrate 15 and the counter substrate 20 can be sufficiently suppressed. Among these, inorganic insulating materials such as glass frit are preferable. In this case, the dimensional change of the insulating material 34 is smaller than when the insulating material is an organic insulating material.

  The coloring material contained in the insulating material 34 may be any coloring material that colors the insulating material 34. Examples of such coloring materials include oxides of transition metals, carbon-based materials, organic dyes, and the like. It can be mentioned. These may be used alone or in combination of two or more.

  Examples of the transition metal oxide include copper oxide, iron oxide, cobalt oxide and manganese oxide. These may be used alone or in combination of two or more.

  The thickness of the insulating material 34 from the transparent substrate 11 is usually 10 to 30 μm, preferably 15 to 25 μm.

(Protective layer)
The protective layer 35 is made of an insulating material. As the insulating material, the same material as the insulating material constituting the insulating material 34 can be used.

  The protective layer 35 may or may not contain a coloring material, as long as the coloring material is contained at a content rate smaller than the content rate in the insulating material 34.

  Here, the protective layer 35 preferably contains no coloring material. Here, "containing no colorant" means that the content of the colorant is 0.4% by mass or less, as described above. In this case, the colorant can be prevented from entering the electrolyte 40. For this reason, according to the photoelectric conversion element 100, the deterioration of the photoelectric conversion characteristic due to the mixing of the coloring material can be sufficiently suppressed, and it is possible to have more excellent durability.

  Here, the colorant refers to a substance having an absorption peak in the wavelength region of visible light, but usually means the same colorant as the colorant contained in the insulating material 34. For example, if the colorant contained in the insulating material 34 is an oxide of a transition metal, the colorant in the protective layer 35 is also an oxide of a transition metal.

  The thickness of the protective layer 35 from the surface of the insulating material 34 is usually 3 to 20 μm, preferably 5 to 10 μm.

(Conductive substrate)
The conductive substrate 15 has the transparent substrate 11 and the transparent conductive layer 12 as described above.

  The material constituting the transparent substrate 11 may be, for example, a transparent material, and as such a transparent material, for example, glass such as borosilicate glass, soda lime glass, white sheet glass, quartz glass, polyethylene terephthalate (PET) And polyethylene naphthalate (PEN), polycarbonate (PC), and polyether sulfone (PES). Although the thickness of the transparent substrate 11 is suitably determined according to the size of the photoelectric conversion element 100 and is not specifically limited, For example, what is necessary is just to make it the range of 50-5000 micrometers.

Examples of the material constituting the transparent conductive layer 12 include conductive metal oxides such as tin-doped indium oxide (ITO), tin oxide (SnO ₂ ), and fluorine-doped tin oxide (FTO). The transparent conductive layer 12 may be composed of a single layer or a laminate of multiple layers containing different conductive metal oxides. When the transparent conductive layer 12 is comprised by a single | mono layer, since it has high heat resistance and chemical resistance, it is preferable that the transparent conductive layer 12 contains FTO. The thickness of the transparent conductive layer 12 may be, for example, in the range of 0.01 to 2 μm.

(Opposite substrate)
The counter substrate 20 includes the metal substrate 21 and the catalyst layer 22 as described above.

  The metal substrate 21 may be made of a metal, which is preferably a metal that can form a passive state. In this case, since the metal substrate 21 is less likely to be corroded by the electrolyte 40, the photoelectric conversion element 100 can have more excellent durability. As a metal which can form a passive state, titanium, nickel, molybdenum, tungsten, aluminum, stainless steel or these alloys etc. are mentioned, for example. The thickness of the metal substrate 21 is appropriately determined in accordance with the size of the photoelectric conversion element 100 and is not particularly limited, but may be, for example, 0.005 to 0.1 mm.

  The catalyst layer 22 is made of platinum, a carbon-based material, a conductive polymer, or the like. Here, carbon black and carbon nanotubes are suitably used as the carbon-based material.

(Oxide semiconductor layer)
The oxide semiconductor layer 13 is composed of oxide semiconductor particles. Examples of such oxide semiconductor particles include titanium oxide (TiO ₂ ), silicon oxide (SiO ₂ ), zinc oxide (ZnO), tungsten oxide (WO ₃ ), niobium oxide (Nb ₂ O ₅ ), and strontium titanate. (SrTiO ₃ ), tin oxide (SnO ₂ ), and the like.

  The thickness of the oxide semiconductor layer 13 is not particularly limited, but is usually 0.5 to 50 μm.

(Pigment)
As the dye, for example, a ruthenium complex having a ligand containing a bipyridine structure, a terpyridine structure or the like, a photosensitizing dye such as an organic dye such as porphyrin, eosin, rhodamine or merocyanine, or an organic matter such as a lead halide perovskite crystal -Inorganic composite dyes and the like can be mentioned. For example, CH ₃ NH ₃ PbX ₃ (X = Cl, Br, I) is used as the lead halide-based perovskite. Among the above dyes, a ruthenium complex having a ligand containing a bipyridine structure or a terpyridine structure is preferable. In this case, the photoelectric conversion characteristics of the photoelectric conversion element 100 can be further improved. In addition, when using a photosensitizing dye as a pigment | dye, the photoelectric conversion element 100 turns into a dye-sensitized photoelectric conversion element.

(Sealing part)
Examples of the material constituting the sealing portion 30A include ionomer, ethylene-vinyl acetate anhydride copolymer, ethylene-methacrylic acid copolymer, modified polyolefin resin including ethylene-vinyl alcohol copolymer, and the like, UV curable resin, And resins such as vinyl alcohol polymers.

  The thickness of the sealing portion 30A is usually 20 to 90 μm, preferably 40 to 80 μm.

(Electrolytes)
The electrolyte 40 contains a redox couple and an organic solvent. As the organic solvent, acetonitrile, methoxyacetonitrile, methoxypropionitrile, propionitrile, ethylene carbonate, propylene carbonate, diethyl carbonate, γ-butyrolactone, valeronitrile, and the like can be used. As a redox pair, in addition to a redox pair containing a halogen atom such as iodide ion / polyiodide ion (eg, I ⁻ / I ₃ ⁻ ), bromide ion / polybromide ion, etc., a zinc complex, iron complex, cobalt complex, etc. And redox couples of The iodide ion / polyiodide ion can be formed of iodine (I ₂ ) and a salt (ionic liquid or solid salt) containing iodide (I ⁻ ) as an anion. When using an ionic liquid having an iodide as an anion, only iodine may be added, and when using an organic solvent, or using an ionic liquid other than an iodide as an anion, as an anion such as LiI or tetrabutylammonium iodide. iodide (I ^-) may be added salt containing. The photoelectric conversion element 100 is useful when the redox couple contains a halogen atom. When the colorant is composed of a transition metal oxide and the redox couple in the electrolyte 40 contains a halogen atom, the colorant and the redox couple in the electrolyte 40 may react in some way. In that respect, in the photoelectric conversion element 100, since the protective layer 35 is provided on the surface of the insulating material 34, the amount of the coloring material mixed in the electrolyte 40 can be reduced. As a result, the amount of coloring material that reacts with the redox couple in the electrolyte 40 can be reduced.

  The electrolyte 40 may be replaced with an organic solvent and an ionic liquid may be used. As the ionic liquid, for example, a known iodine salt such as pyridinium salt, imidazolium salt, triazolium salt and the like, which is a normal temperature molten salt in a molten state at around room temperature is used. As such room temperature molten salt, for example, 1-hexyl-3-methylimidazolium iodide, 1-ethyl-3-propylimidazolium iodide, 1-ethyl-3-methylimidazolium iodide, 1,2 -Dimethyl-3-propylimidazolium iodide, 1-butyl-3-methylimidazolium iodide, or 1-methyl-3-propylimidazolium iodide is preferably used.

  In addition, as the electrolyte 40, a mixture of the ionic liquid and the organic solvent may be used instead of the organic solvent.

  Also, additives can be added to the electrolyte 40. As the additive, LiI, tetrabutylammonium iodide, 4-t-butylpyridine, guanidinium thiocyanate, 1-methylbenzimidazole, 1-butylbenzimidazole and the like can be mentioned.

Furthermore, as the electrolyte 40, a nanocomposite gel electrolyte which is a quasi-solid electrolyte formed by kneading nanoparticles such as SiO ₂ , TiO ₂ and carbon nanotubes into the above-mentioned electrolyte may be used, and polyvinylidene fluoride may be used. An electrolyte gelled with an organic gelling agent such as polyethylene oxide derivative or amino acid derivative may be used.

Incidentally, the electrolyte 40, an iodide ion / polyiodide ions (e.g. ^I - / _{I 3} ^-) comprises a redox pair consisting of, polyiodide ions (e.g. _{I 3} ^-) concentration is less than 0.010 mol / l Is preferred. In this case, the leakage current can be further reduced because the concentration of the electron carrying polyiodide ion is low. Therefore, the open circuit voltage can be further increased, so that the photoelectric conversion characteristics can be further improved. In particular, the concentration of polyiodide ion is preferably 0.005 mol / liter or less, and more preferably 0 to 2 × 10 ⁻⁴ mol / liter. In this case, when the photoelectric conversion element 100 is viewed from the light incident side of the conductive substrate 15, the color of the electrolyte 40 can be made inconspicuous.

  Next, a method of manufacturing the photoelectric conversion element 100 will be described.

  First, a laminate formed by forming a transparent conductive layer on one transparent substrate 11 is prepared.

  As a method for forming the transparent conductive layer, a sputtering method, a vapor deposition method, a spray thermal decomposition method, a CVD method, or the like is used.

  Next, grooves 90 are formed in the transparent conductive layer, and a plurality of transparent conductive layers 12 disposed in an insulated state via the grooves 90 are formed.

The groove 90 can be formed by a laser scribing method using, for example, a YAG laser or a CO ₂ laser as a light source.

  Thus, the plurality of transparent conductive layers 12 are formed on the transparent substrate 11.

  Furthermore, a precursor of the insulating material 34 is formed so as to enter the groove 90 and also cover the edge of the transparent conductive layer 12. The insulating material 34 can be formed, for example, by applying and drying an insulating material forming paste containing an insulating material and a coloring material.

  Subsequently, a precursor of the protective layer 35 is formed so as to cover the entire surface of the precursor of the insulating material 34 other than the portions in contact with the transparent substrate 11 and the transparent conductive layer 12. The protective layer 35 can be formed, for example, by applying and drying a protective layer-forming paste containing an insulating material. At this time, the content of the coloring material in the precursor of the protective layer 35 is made smaller than the content of the coloring material in the precursor of the insulating material 34.

  Furthermore, a precursor of the oxide semiconductor layer 13 is formed on each of the transparent conductive layers 12.

  The precursor of the oxide semiconductor layer 13 is obtained by printing and then drying a paste for forming an oxide semiconductor layer for forming the oxide semiconductor layer 13. The oxide semiconductor layer-forming paste contains, in addition to the oxide semiconductor particles, a resin such as polyethylene glycol or ethyl cellulose and a solvent such as terpineol.

  As a printing method of the oxide semiconductor layer forming paste, for example, a screen printing method, a doctor blade method, or a bar coating method can be used.

  Next, the precursor of the insulating material 34, the precursor of the protective layer 35, and the precursor of the oxide semiconductor layer 13 are fired at once to form the insulating material 34, the protective layer 35, and the oxide semiconductor layer 13.

  At this time, the firing temperature varies depending on the type of the oxide semiconductor particles and the glass frit, but is usually 350 to 600 ° C., and the firing time also varies depending on the type of the oxide semiconductor particles etc. is there.

  Thus, an electrode structure having the conductive substrate 15 on which the insulating material 34 and the protective layer 35 are formed and the oxide semiconductor layer 13 is obtained.

  Next, a dye is supported on the oxide semiconductor layer 13 of the electrode structure obtained as described above. For this purpose, for example, the electrode structure is immersed in a solution containing a dye, and after the dye is adsorbed to the oxide semiconductor layer 13, excess dye is washed away with the solvent component of the solution and dried. Just do it.

  Next, the electrolyte 40 is disposed on the oxide semiconductor layer 13.

  Next, an integrated sealing portion forming body for forming an integrated sealing portion is prepared. The integrated sealing portion forming body prepares one sealing resin film made of a material constituting the integrated sealing portion, and the rectangular resin opening corresponding to the number of cells 50 is provided in the sealing resin film. Can be obtained by forming The integrated sealing portion forming body has a structure in which a plurality of annular sealing portion forming bodies to be the sealing portion 30A are integrated.

  As a resin film for sealing, for example, ionomer, ethylene-vinyl acetate anhydride copolymer, ethylene-methacrylic acid copolymer, modified polyolefin resin including ethylene-vinyl alcohol copolymer etc., UV curable resin, and vinyl And resins such as alcohol polymers.

  Then, the integrated sealing portion forming body is adhered to the protective layer 35 of the conductive substrate 15. At this time, the integrated sealing portion forming body is adhered so as to overlap with the protective layer 35. The adhesion of the integrated sealing portion forming body to the protective layer 35 can be performed by heating and melting the integrated sealing portion forming body.

  On the other hand, the same number of counter substrates 20 as the number of cells 50 are prepared.

  The counter substrate 20 can be obtained by forming the catalyst layer 22 on the metal substrate 21.

  Next, the opposing substrate 20 and the integrated sealing portion forming body bonded to the electrode structure are stacked and heated and melted while pressing the integrated sealing portion forming body. Thus, an integrated sealing portion is formed between the electrode structure and the counter substrate 20. The formation of the integral sealing portion may be performed under atmospheric pressure or under reduced pressure, but is preferably performed under reduced pressure.

  The photoelectric conversion element 100 is obtained as described above.

  In the above description, in order to form the insulating material 34, the protective layer 35, and the oxide semiconductor layer 13, the precursor of the insulating material 34, the precursor of the protective layer 35, and the precursor of the oxide semiconductor layer 13 are collectively provided. The insulating material 34, the protective layer 35, and the oxide semiconductor layer 13 may be separately formed by firing a precursor.

  The present invention is not limited to the above embodiment. For example, in the above embodiment, although the protective layer 35 is interposed not only between the insulating material 34 and the electrolyte 40 but also between the insulating material 34 and the sealing portion 30A, the photoelectric conversion element shown in FIG. Like 200, the protective layer 35 may not be interposed between the insulating material 34 and the sealing portion 30A. That is, the protective layer 35 may not have the sandwiching portion 35 b. In this case, the sealing portion 30A and the insulating material 34 are in direct contact with each other.

  Moreover, in the said embodiment, although the protective layer 35 is comprised by the coating | coated part 35a, the clamping part 35b, and the coating | coated part 35a or the exposure part 35c, the protective layer 35 is comprised only by the coating | coated part 35a. It is also good. That is, the protective layer 35 may not have the sandwiching portion 35 b and the exposed portion 35 c.

  Furthermore, in the said embodiment, although the photoelectric conversion element 100 has the some cell 50, the photoelectric conversion element of this invention may have only one cell.

  In the above embodiment, the plurality of cells 50 are connected in series, but may be connected in parallel.

  Furthermore, in the above embodiment, the counter substrate 20 has conductivity, but if a counter electrode is separately provided closer to the oxide semiconductor layer 13 than the counter substrate 20, the counter substrate 20 has conductivity. You do not have to.

  Hereinafter, the contents of the present invention will be more specifically described by way of examples, but the present invention is not limited to the following examples.

Example 1
First, a laminate was prepared by forming a transparent conductive layer of FTO having a thickness of 1 μm on a transparent substrate of a thickness of 1 mm made of glass. Next, grooves 90 were formed in the transparent conductive layer with a CO ₂ laser (V-460 manufactured by Universal Systems Inc.) to form four transparent conductive layers 12. At this time, the width of the groove 90 was 1 mm. The transparent conductive layers 12 were each formed in a rectangular shape of 4.6 cm × 2.0 cm.

  Furthermore, the precursor of the insulating material 34 was formed so as to enter the groove 90 between the adjacent transparent conductive layers 12 and to cover the edge of the transparent conductive layer 12 on both sides of the groove 90. The precursor of the insulating material 34 was formed by applying and drying an insulating material forming paste containing a glass frit and a coloring material by screen printing. At this time, in the paste for insulating material formation, the coloring material was contained so that the content rate of the coloring material in the insulating material 34 was 15% by mass. As a coloring material, what consists of iron oxide, copper oxide, and manganese oxide was used.

  Subsequently, a precursor of the protective layer 35 was formed to cover the entire precursor of the insulating material 34. The protective layer 35 was formed by applying and drying a protective layer forming paste made of glass frit. At this time, the content of the coloring material in the protective layer-forming paste was 0 mass%.

  Furthermore, on each of the transparent conductive layers 12, a precursor of the oxide semiconductor layer 13 was formed. The precursor of the oxide semiconductor layer 13 was formed by applying a paste for forming an oxide semiconductor layer containing titania particles by screen printing and drying it.

  Next, the precursor of the insulating material 34, the precursor of the protective layer 35, and the precursor of the oxide semiconductor layer 13 were baked at 500 ° C. for 1 hour. Thus, an electrode structure having the conductive substrate 15 on which the insulating material 34 and the protective layer 35 were formed and the oxide semiconductor layer 13 was obtained.

  Next, the above electrode structure is contained in a dye solution containing 0.2 mM of a photosensitizing dye consisting of N719, and a solvent containing a mixed solvent of acetonitrile and tert-butanol in a volume ratio of 1: 1. After soaking overnight, it was taken out and dried, and the photosensitizing dye was supported on the oxide semiconductor layer.

Next, on the oxide semiconductor layer, 1-hexyl-3-methylimidazolium iodide 2M, I ₂ 0.002M, n-methylbenzimidazole 0.3M in a solvent consisting of 3-methoxypropionitrile An electrolyte consisting of guanidinium thiocyanate 0.1 M was dropped and dried to arrange the electrolyte.

  Next, an integrated sealing portion forming body for forming a sealing portion was prepared. An integrated sealing part formation body prepares the resin film for sealing of 1 sheet which consists of maleic anhydride modified polyethylene (brand name: made by DuPont) 8.0 cm x 4.6 cm x 50 micrometers, and it seals It obtained by forming four square-shaped openings in the resin film for termination. At this time, an integrated sealing portion forming body was produced so that each opening had a size of 1.7 cm × 4.4 cm × 50 μm and the width of the integrated sealing portion forming body was 4 mm.

  Then, after the integrated sealing portion forming body is superimposed on the protective layer 35 of the electrode structure, the integrated sealing portion forming body is heated and melted to adhere to the protective layer 35 on the electrode structure. I did.

  Next, four opposing substrates 20 were prepared. The four opposing substrates 20 were prepared by forming a catalyst layer consisting of platinum with a thickness of 5 nm on a 4.6 cm × 1.9 cm × 40 μm titanium foil by a sputtering method.

  Then, the integrated sealing portion forming body bonded to the above electrode structure and the opposing substrate 20 were placed to face each other. And in this state, the integrated sealing portion forming body was heated and melted while pressing the integrated sealing portion forming body. Thus, a sealing portion was formed between the electrode structure and the counter substrate 20.

  The DSC module was obtained as described above.

(Example 2)
A DSC module was produced in the same manner as in Example 1 except that the protective layer-forming paste contained a colorant such that the content of the colorant in the protective layer 35 was 3% by mass.

(Comparative example 1)
A DSC module was produced in the same manner as in Example 1 except that the protective layer forming paste was not applied on the precursor of the insulating material 34.

(Comparative example 2)
A DSC module was manufactured in the same manner as in Example 1 except that the protective layer forming paste of Example 1 was used instead of the insulating material forming paste when forming the precursor of the insulating material 34.

(Characteristics evaluation)
(durability)
The initial output ( _{0 0} ) was measured for the DSC modules obtained in Examples 1 and 2 and Comparative Examples 1 and 2. Then, the output ((eta)) after performing the heat cycle test according to JISC8938 was also measured about the DSC module obtained by Example 1-2 and Comparative Examples 1-2. And the following formula:
Output holding ratio (%) = / / _{0 0} × 100
The output retention ratio (output retention ratio) was calculated based on The results are shown in Table 1.

(appearance)
Moreover, the external appearance when it saw from the light-incidence side was evaluated about the DSC module obtained by Example 1-2 and Comparative Examples 1-2. The results are shown in Table 1. In addition, in Table 1, "(double-circle)", "(circle)", and "x" are each evaluated as follows about an external appearance.
・ ・ ・ · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·. Looks good

  As shown in Table 1, it was found that the DSC modules of Examples 1 and 2 exhibited higher output retention than the DSC module of Comparative Example 1. Moreover, it turned out that the DSC module of Examples 1-2 can maintain a favorable external appearance similarly to the DSC module of Comparative Example 1. Further, it was found that the DSC module of Comparative Example 2 exhibited a higher output retention rate than the DSC module of Comparative Example 1. However, it was found that the DSC module of Comparative Example 2 can not maintain a good appearance.

  As mentioned above, according to the photoelectric conversion element of this invention, it was confirmed that it has the outstanding durability, maintaining a favorable external appearance.

11 Transparent substrate 12 Transparent conductive layer 13 Oxide semiconductor layer 15 Conductive substrate 20 Counter substrate 30A Sealing portion 34 Insulating material 35 Protective layer 35a Coating portion 40 Electrolyte 50 Photoelectric conversion cell 90 ... groove 100, 200 ... photoelectric conversion element

Claims (5)

Has at least one photoelectric conversion cell,
The photoelectric conversion cell is
A transparent substrate and a conductive substrate having a transparent conductive layer provided on the transparent substrate;
An opposing substrate facing the conductive substrate;
An oxide semiconductor layer provided on the conductive substrate or the counter substrate;
An electrolyte disposed between the conductive substrate and the counter substrate and containing a redox couple;
An annular sealing portion for joining the conductive substrate and the counter substrate;
A colored insulating material provided between the conductive substrate and the sealing portion;
A protective layer having a covering portion provided on the surface of the insulating material and between the insulating material and the electrolyte;
The insulating material contains a colorant,
The photoelectric conversion element whose content rate of the coloring material in the said protective layer is smaller than the content rate of the coloring material in the said insulating material.   The photoelectric conversion element according to claim 1, wherein the protective layer does not contain a colorant.   The photoelectric conversion element according to claim 1, wherein the protective layer is interposed between the sealing portion and the insulating material.   The photoelectric conversion element according to any one of claims 1 to 3, wherein the coloring material is made of a transition metal oxide.   The photoelectric conversion element according to claim 4, wherein the redox couple contains a halogen atom.

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