JP6539081B2 - Photoelectric conversion element - Google Patents

Description

  The present invention relates to a photoelectric conversion element.

  The dye-sensitized solar cell is a next-generation photoelectric conversion element that has been attracting attention because it has been developed by Gretzel et al., Switzerland, and has advantages such as high photoelectric conversion efficiency and low manufacturing cost.

  A photoelectric conversion element using a dye such as such a dye-sensitized solar cell generally has at least one photoelectric conversion cell, and the photoelectric conversion cell comprises an electrode substrate, an opposing substrate facing the electrode substrate, and an electrode substrate Alternatively, an oxide semiconductor layer provided over the counter substrate, a sealing portion provided so as to surround the oxide semiconductor layer, and connecting the electrode substrate and the counter substrate, and an electrolyte provided between the electrode substrate and the counter substrate Have.

  As such photoelectric conversion elements, those aiming at weight reduction have also been developed (see, for example, Patent Document 1 below), and in the photoelectric conversion elements described in Patent Document 1 below, the electrode substrate is a transparent resin film and And the laminated body of the conductive layer provided on it.

JP, 2006-159886, A

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

  That is, the photoelectric conversion element described in Patent Document 1 has room for improvement in terms of long-term durability.

  This invention is made in view of the said situation, and it aims at providing the photoelectric conversion element which can improve long-term durability.

  The inventors of the present invention examined the cause of the above problems in the photoelectric conversion element described in Patent Document 1. As a transparent resin film is important for achieving weight reduction, it is more desirable than an inorganic material such as glass. The inventors of the present invention thought that air and moisture from the air easily penetrated, and this air and moisture eventually penetrated into the electrolyte to reduce the long-term durability of the photoelectric conversion element. Therefore, as a result of further intensive studies, the present inventor has found that the above-mentioned problems can be solved by providing a glass layer on the opposite side of the transparent resin film to the conductive layer, and the present invention has been completed.

That is, the present invention includes at least one photoelectric conversion cell, and the photoelectric conversion cell includes an electrode substrate, an opposing substrate facing the electrode substrate, and an oxide semiconductor layer provided on the electrode substrate or the opposing substrate. The electrode substrate is provided so as to surround the oxide semiconductor layer, and includes a sealing portion connecting the electrode substrate and the opposite substrate, and an electrolyte provided between the electrode substrate and the opposite substrate. A resin film, a conductive layer provided on the electrolyte side of the resin film, a glass layer provided on the opposite side of the resin layer of the resin film, and the resin film and the glass layer the photoelectric conversion element having an adhesive layer for bonding the resin film and the glass layer, the peripheral portion and the contact of at least the resin film in the electrode substrate It further comprises a covering part which covers the peripheral part of a layer, and the covering part is constituted by a part of back sheet provided so that the counter substrate may be arranged between the photoelectric conversion cell and the electrode substrate. The photoelectric conversion element, wherein the back sheet includes a metal layer .

  According to the photoelectric conversion element of the present invention, in the electrode substrate, the glass layer is provided on the side opposite to the conductive layer in the resin film, so the area of the surface on which air and moisture enter in the resin film is sufficiently reduced. Thus, the gas barrier properties of the electrode substrate can be improved. For this reason, it becomes difficult for air and moisture from the outside to penetrate into the resin film of the electrode substrate, and it can be sufficiently suppressed that air and moisture will eventually enter the electrolyte of the photoelectric conversion cell. Therefore, according to the photoelectric conversion element of the present invention, long-term durability can be improved.

Further, according to the photoelectric conversion element of this, since the resin film and the glass layer are fixed by the adhesive layer, between the resin film and the glass layer when the photoelectric conversion element is placed in a large environment of temperature change It is sufficiently suppressed that the gap between For this reason, the output characteristics of the photoelectric conversion element are more stable.
In addition, by covering the peripheral portion of the resin film and the peripheral portion of the adhesive layer with the covering portion, the area of the surface on which air and moisture enter in the resin film and the adhesive layer can be sufficiently reduced. The gas barrier properties of the substrate can be further improved. For this reason, it is difficult for air and moisture from the outside to penetrate the resin film and the adhesive layer from the peripheral edge of the resin film and the peripheral edge of the adhesive layer, and air and moisture enter the electrolyte of the photoelectric conversion cell. It can be more sufficiently suppressed. Therefore, according to the photoelectric conversion element of the present invention, long-term durability can be further improved.
In addition, the sealing portion and the back sheet are particularly hard to pass moisture and air. For this reason, when the covering portion is configured of a part of the sealing portion or a part of the back sheet, air or moisture from the outside hardly penetrates the covering portion. For this reason, it becomes difficult for air and moisture from the outside to penetrate into the resin film and the adhesive layer, and the air and moisture can be more sufficiently suppressed from entering the electrolyte of the photoelectric conversion cell. Therefore, according to the photoelectric conversion element of the present invention, long-term durability can be further improved.

  In the photoelectric conversion element, it is preferable that at least one of the resin film, the adhesive layer, and the glass layer contains an ultraviolet absorber.

  According to this photoelectric conversion element, ultraviolet light is absorbed by the ultraviolet light absorber contained in at least one of the resin film, the adhesive layer, and the glass layer among the light incident on the electrode substrate. For this reason, deterioration of the photoelectric conversion cell due to ultraviolet light is sufficiently suppressed.

  According to the present invention, a photoelectric conversion element capable of improving long-term durability is provided.

It is sectional drawing which shows 1st Embodiment of the photoelectric conversion element of this invention. It is sectional drawing which shows 2nd Embodiment of the photoelectric conversion element of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings, the same or equivalent constituent elements are given the same reference numerals, and repeated descriptions are omitted.

First Embodiment
First, a first embodiment of the photoelectric conversion element of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view showing a first embodiment of the photoelectric conversion element of the present invention.

  As shown in FIG. 1, the photoelectric conversion element 100 is configured of one photoelectric conversion cell 60, and the photoelectric conversion cell 60 is opposed to the electrode substrate 10 capable of transmitting light and the electrode substrate 10. An annular sealing portion 40 provided so as to surround the substrate 20, the oxide semiconductor layer 30 provided over the counter substrate 20, and the oxide semiconductor layer 30, and connecting the electrode substrate 10 and the counter substrate 20, oxidation A dye to be adsorbed to the object semiconductor layer 30 and an electrolyte 50 provided between the electrode substrate 10 and the counter substrate 20 are provided.

  The electrode substrate 10 includes a resin film 11, a conductive layer 12 provided on the electrolyte 50 side of the resin film 11, and a glass layer 14 provided on the opposite side (light incident side) of the resin film 11 to the conductive layer 12. A catalyst layer 15 is provided which is provided on the opposite substrate 20 side of the conductive layer 12 and contributes to the reduction of the electrolyte 50. Furthermore, in the present embodiment, the electrode substrate 10 further includes an adhesive layer 13 for bonding the resin film 11 and the glass layer 14 between the resin film 11 and the glass layer 14.

  The opposing substrate 20 is made of a conductive substrate 21.

  According to the photoelectric conversion element 100, since the glass layer 14 is provided on the opposite side of the resin film 11 to the conductive layer 12, the area of the surface of the resin film 11 where air and moisture enter can be sufficiently reduced. The gas barrier properties of the electrode substrate 10 can be improved. For this reason, it becomes difficult for air and moisture from the outside to penetrate into the resin film 11 of the electrode substrate 10, and it can be sufficiently suppressed that air and moisture will eventually enter the electrolyte 50 of the photoelectric conversion cell 60. Therefore, according to the photoelectric conversion element 100, long-term durability can be improved.

  The photoelectric conversion element 100 further includes an adhesive layer 13 between the resin film 11 and the glass layer 14 for bonding the resin film 11 and the glass layer 14. In this case, since the resin film 11 and the glass layer 14 are fixed by the adhesive layer 13, the gap between the resin film 11 and the glass layer 14 when the photoelectric conversion element 100 is placed under a large temperature change environment. Changes are sufficiently suppressed. For this reason, the output characteristics of the photoelectric conversion element 100 are more stable.

  Next, the electrode substrate 10, the counter substrate 20, the oxide semiconductor layer 30, the sealing portion 40, the electrolyte 50, and the dye are described in detail.

<Electrode substrate>
As described above, the electrode substrate 10 has the resin film 11, the conductive layer 12 as an electrode provided on the electrolyte 50 side of the resin film 11, and the side opposite to the conductive layer 12 of the resin film 11 (light incident side) And a catalyst layer 15 which is provided on the side of the opposite substrate 20 of the conductive layer 12 and which contributes to the reduction of the electrolyte 50.

(Resin film)
The material constituting the resin film 11 may be a transparent resin material, and as such a transparent resin material, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyimide (PI) And polyether sulfone (PES). Although the thickness of the resin film 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 50-500 micrometers.

(Conductive layer)
Examples of the material constituting the 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 conductive layer 12 may be a single layer or a laminate of a plurality of layers composed of different conductive metal oxides. When the conductive layer 12 is formed of a single layer, the conductive layer 12 is preferably formed of FTO because it has high heat resistance and chemical resistance. The thickness of the conductive layer 12 may be, for example, in the range of 0.01 to 2 μm.

(Adhesive layer)
The adhesive layer 13 may be made of an adhesive capable of adhering the resin film 11 and the glass layer 14. As such an adhesive, for example, an adhesive such as an acrylic adhesive or an epoxy adhesive can be used. These adhesives may be any of a photocurable adhesive, a thermosetting adhesive or a two-component adhesive.

  However, it is preferable that the adhesive layer 13 have a refractive index between the refractive index of the resin film 11 and the refractive index of the glass layer 14. In this case, reflection of light at the interface between the resin film 11 and the adhesive layer 13 and at the interface between the adhesive layer 13 and the glass layer 14 can be reduced, so that light can be sufficiently guided to the oxide semiconductor layer 30.

(Glass layer)
The glass layer 14 may be made of a glass material, and examples of the glass layer 14 include borosilicate glass, soda lime glass, alkali-free glass and quartz glass.

  The glass layer 14 may or may not have flexibility, but preferably has flexibility. In this case, not only the resin film 11 but also the glass layer 14 has flexibility, and the photoelectric conversion element 100 is fixed to the curved surface even if the installation surface of the installation object of the photoelectric conversion element 100 is a curved surface. In that case, since the curved surface shape can be made to follow without damaging the glass layer 14, the photoelectric conversion element 100 can be installed on the curved surface.

The term “flexible” means that the long edges of the 50 mm × 200 mm glass layer (each 5 mm wide) are horizontally fixed in an environment of 20 ° C., and the center of the glass layer is The maximum deformation rate of the deflection of the glass layer when the load is applied is over 20%. Here, the maximum deformation rate refers to a value calculated based on the following equation.
Maximum deformation rate (%) = 100 × (maximum displacement / thickness of glass layer)
Therefore, for example, when the glass layer having a thickness of 0.04 mm is bent by applying a load as described above and the maximum deformation amount is 0.01 mm, the maximum deformation rate is 25%, and this glass layer is flexible. It will have sex.

  The thickness of the glass layer 14 may be smaller than the thickness of the resin film 11, but is usually 0.2 mm or less, preferably 0.1 mm or less.

(Catalyst layer)
The catalyst layer 15 is made of platinum, a carbon-based material, a conductive polymer, or the like.

(UV absorber)
It is preferable that at least one of the resin film 11, the adhesive layer 13 and the glass layer 14 described above contains an ultraviolet absorber. In this case, of the light incident on the electrode substrate 10, the ultraviolet light is absorbed by the ultraviolet light absorber contained in at least one of the resin film 11, the adhesive layer 13 and the glass layer 14. For this reason, deterioration of the photoelectric conversion cell 60 due to ultraviolet light is sufficiently suppressed.

  Here, it is preferable that the adhesive layer 13 of the resin film 11, the adhesive layer 13, and the glass layer 14 contain an ultraviolet absorber. In this case, as compared with the case where the ultraviolet light absorber is contained in the resin film 11 or the glass layer 14, scratches and peeling are less likely to occur in the adhesive layer 13, and the deterioration of the ultraviolet light absorbing performance can be sufficiently suppressed.

  An ultraviolet absorber should just be a material which absorbs an ultraviolet-ray. Such UV absorbers include, for example, cerium oxide, zinc oxide, triazine derivatives, benzotriazole derivatives and benzophenone derivatives. These can be used singly or in combination of two or more.

  In addition, although the addition ratio in particular of the ultraviolet absorber in the electrode substrate 10 is not restrict | limited, Preferably it is 0.01-50 mass parts (phr).

<Opposite substrate>
As described above, the counter substrate 20 includes the conductive substrate 21 which doubles as a substrate and an electrode.

(Conductive substrate)
The conductive substrate 21 is made of, for example, a corrosion-resistant metal material such as titanium, nickel, platinum, molybdenum, tungsten, aluminum, stainless steel or the like. In addition, the conductive substrate 21 may be formed of a laminate in which a conductive layer made of a conductive oxide such as ITO or FTO is formed as an electrode on the above-described resin film 11 by dividing the substrate and the electrode. It may be a laminate in which a conductive layer made of a conductive oxide such as ITO or FTO is formed thereon. Here, in the case where the conductive substrate 21 is formed of a laminate in which a conductive layer is formed on the resin film 11, the conductive substrate 21 may have the same configuration as the electrode substrate 10. That is, the conductive substrate 21 may have the glass layer 14 provided on the side opposite to the conductive layer in the resin film 11. In this case, since the glass layer 14 is provided on the opposite side of the resin film 11 to the conductive layer, the area of the surface of the resin film 11 where air and moisture enter can be sufficiently reduced, and the gas barrier properties of the conductive substrate 21 can be improved. It can be improved. For this reason, air and moisture from the outside are less likely to penetrate into the resin film 11 of the conductive substrate 21, and it can be sufficiently suppressed that air and moisture will eventually enter the electrolyte 50 of the photoelectric conversion cell 60. Therefore, the long-term durability of the photoelectric conversion element 100 can be improved. The thickness of the conductive 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, 0.01 to 4 mm.

<Oxide semiconductor layer>
The oxide semiconductor layer 30 is composed of oxide semiconductor particles. The oxide semiconductor particles are, for example, titanium oxide (TiO ₂ ), zinc oxide (ZnO), tungsten oxide (WO ₃ ), niobium oxide (Nb ₂ O ₅ ), strontium titanate (SrTiO ₃ ), tin oxide (SnO ₂ ) , Indium oxide (In ₃ O ₃ ), zirconium oxide (ZrO ₂ ), thallium oxide (Ta ₂ O ₅ ), lanthanum oxide (La ₂ O ₃ ), yttrium oxide (Y ₂ O ₃ ), holmium oxide (Ho ₂ O ₃ ) ₃ ) Bismuth oxide (Bi ₂ O ₃ ), cerium oxide (CeO ₂ ), aluminum oxide (Al ₂ O ₃ ) or two or more of these. The thickness of the oxide semiconductor layer 30 may be, for example, 0.1 to 100 μm.

<Sealing part>
Examples of the sealing portion 40 include thermoplastic resins such as modified polyolefin resin and vinyl alcohol polymer, and resins such as ultraviolet curing resin. Examples of the modified polyolefin resin include ionomers, ethylene-vinyl acetate anhydride copolymers, ethylene-methacrylic acid copolymers and ethylene-vinyl alcohol copolymers. These resins can be used alone or in combination of two or more.

<Electrolyte>
The electrolyte 50 contains, for example, a redox couple (such as I ⁻ / I ₃ ⁻ ) formed by mixing iodine and an iodide salt, and an organic solvent. As the organic solvent, acetonitrile, methoxyacetonitrile, methoxypropionitrile, propionitrile, ethylene carbonate, propylene carbonate, diethyl carbonate, γ-butyrolactone, valeronitrile, pivalonitrile, glutaronitrile, methacrylonitrile, isobutyronitrile, Phenyl acetonitrile, acrylonitrile, succinonitrile, oxalonitrile, pentanitrile, adiponitrile and the like can be used. Examples of the redox couple include, in addition to I ⁻ / I ₃ ⁻ , redox pairs such as bromine / bromide ion, zinc complex, iron complex, cobalt complex and the like. The electrolyte 50 may be replaced with an organic solvent and an ionic liquid may be used. As the ionic liquid, for example, known iodine salts such as pyridinium salts, imidazolium salts and triazolium salts are used. As such an iodine salt, for example, 1-hexyl-3-methylimidazolium iodide, 1-ethyl-3-propylimidazolium iodide, dimethylimidazolium iodide, ethylmethylimidazolium iodide, dimethylpropylimidazo Preferably, lithium iodide, butylmethylimidazolium iodide or methylpropylimidazolium iodide is used.

  Further, as the electrolyte 50, 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 50. Examples of the additive include benzimidazole such as 1-methylbenzimidazole (NMB) and 1-butylbenzimidazole (NBB), LiI, I ₂ , 4-t-butylpyridine, guanidinium thiocyanate and the like. Among them, benzimidazole is preferred as the additive.

Furthermore, as the electrolyte 50, 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.

<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. When a photosensitizing dye is used as the dye, the photoelectric conversion element 100 is a dye-sensitized photoelectric conversion element.

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

  First, the counter electrode consisting of the electrode substrate 10 is prepared. In the electrode substrate 10, the conductive layer 12 is formed on one surface of the resin film 11, the catalyst layer 15 is formed thereon, and the glass layer 14 is adhered on the other surface via the adhesive layer 13. You can get it.

  The conductive layer 12 can be formed on one surface of the resin film 11 by a sputtering method, a vapor deposition method, a CVD method, or the like.

  The catalyst layer 15 can be formed on the conductive layer by a sputtering method or the like.

  Next, the opposing substrate 20 made of the conductive substrate 21 is prepared, and the oxide semiconductor layer 30 is formed on the opposing substrate 20 to form a working electrode. The oxide semiconductor layer 30 can be formed by printing and then baking a porous oxide semiconductor layer-forming paste containing oxide semiconductor particles.

  The oxide semiconductor layer-forming paste contains, in addition to the above-described oxide semiconductor particles, a resin such as polyethylene glycol 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.

  Although a calcination temperature changes with materials of oxide semiconductor particles, it is usually 350-600 ° C. The firing time also varies depending on the material of the oxide semiconductor particles, but is usually 1 to 5 hours.

  Next, a dye is adsorbed on the surface of the oxide semiconductor layer 30 of the working electrode. For this purpose, the working electrode is immersed in a solution containing a dye, and after the dye is adsorbed to the oxide semiconductor layer 30, excess dye is washed away with the solvent component of the solution and dried. The dye may be adsorbed to the oxide semiconductor layer 30. However, after the solution containing a dye is applied to the oxide semiconductor layer 30, the dye may be adsorbed to the oxide semiconductor layer 30 by drying.

  Next, the electrolyte 50 is prepared. The electrolyte 50 may be composed of a solution including a redox couple.

  Next, the electrolyte 50 is disposed on the oxide semiconductor layer 30. The electrolyte 50 can be disposed, for example, by a dropping method or the like.

  Next, an annular sealing portion forming body is prepared. The sealing portion forming body can be obtained, for example, by preparing a sealing resin film and forming one rectangular opening in the sealing resin film.

  Then, the sealing portion forming body is adhered on the counter substrate 20. At this time, adhesion of the sealing portion forming body to the opposite substrate 20 can be performed, for example, by heating and melting the sealing portion forming body.

  Next, after arranging the electrode substrate 10 so as to close the opening of the sealing portion forming body, the electrode substrate 10 is bonded to the sealing portion forming body. At this time, the sealing portion forming body may be adhered to the electrode substrate 10 in advance, and the sealing portion forming body may be bonded to the sealing portion forming body on the counter substrate 20 side. The bonding of the electrode substrate 10 to the sealing portion forming body 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.

Second Embodiment
Next, a second embodiment of the photoelectric conversion element of the present invention will be described with reference to FIG. FIG. 2 is a cross-sectional view showing a second embodiment of the photoelectric conversion element of the present invention.

  As shown in FIG. 2, the photoelectric conversion element 200 of the present embodiment further includes a back sheet 210 provided so that the counter substrate 20 is disposed between the photoelectric conversion cell 60 and the electrode substrate 10. This differs from the photoelectric conversion element 100 of the first embodiment.

  Here, the peripheral portion 210 a of the back sheet 210 covers the peripheral portion of the adhesive layer 13 of the electrode substrate 10 and the peripheral portion of the resin film 11 as a covering portion.

  In the photoelectric conversion element 100 of the first embodiment, the glass layer 14 is not provided on the peripheral portion of the resin film 11 and the peripheral portion of the adhesive layer 13. Therefore, as in the photoelectric conversion element 200 of the present embodiment, the resin film 11 and the adhesive layer are covered by covering the peripheral portion of the resin film 11 and the peripheral portion of the adhesive layer 13 with the peripheral portion 210a of the back sheet 210. 13, the area of the surface on which air and moisture enter can be sufficiently reduced, and the gas barrier properties of the electrode substrate 10 can be further improved. Therefore, air and moisture from the outside hardly enter the resin film 11 and the adhesive layer 13 from the peripheral portion of the resin film 11 and the peripheral portion of the adhesive layer 13, and eventually become within the electrolyte 50 of the photoelectric conversion cell 60. Air and moisture can be more fully suppressed. Therefore, according to the photoelectric conversion element 200, long-term durability can be further improved.

  The back sheet 210 at least includes a weather resistant layer and a metal layer.

  The weather resistant layer may be made of, for example, polyethylene terephthalate or polybutylene terephthalate.

  The thickness of the weathering layer may be, for example, 50 to 300 μm.

  The metal layer may be made of, for example, a metal material containing aluminum. The metal material is usually composed of aluminum alone, but may be an alloy of aluminum and another metal. Other metals include, for example, copper, manganese, zinc, magnesium, lead and bismuth. Specifically, 1000 series aluminum in which a trace amount of other metals is added to 98% or more of pure aluminum is desirable. This is because the 1000 series aluminum is inexpensive and excellent in processability as compared with other aluminum alloys.

  The thickness of the metal layer is not particularly limited, and may be, for example, 12 to 30 μm.

  The back sheet 210 can be bonded to the electrode substrate 10 with a resin. Examples of such resin include butyl rubber, nitrile rubber, thermoplastic resin and the like. These can be used alone or in combination of two or more.

  The present invention is not limited to the above embodiment. For example, although the electrode substrate 10 has the adhesive layer 13 between the resin film 11 and the glass layer 14 in the first and second embodiments, for example, as in the photoelectric conversion element 200 of the second embodiment. If the resin film 11 and the glass layer 14 are fixed by the back sheet 210, the adhesive layer 13 is not necessarily required and can be omitted.

  Moreover, in the said 2nd Embodiment, although the peripheral part of the resin film 11 and the peripheral part of the contact bonding layer 13 are covered by the peripheral part 210a of the back sheet 210, in the photoelectric conversion element 100 of 1st Embodiment, a sealing part A portion of 40 may cover the peripheral portion of the resin film 11 and the peripheral portion of the adhesive layer 13 as a covering portion. Further, a covering portion which is neither the sealing portion 40 nor the back sheet 210 may cover the peripheral portion of the resin film 11 and the peripheral portion of the adhesive layer 13. In this case, the covering portion is preferably made of, for example, the same material as the sealing portion 40.

  Furthermore, in the photoelectric conversion element 100 according to the first embodiment, the oxide semiconductor layer 30 is provided on the counter substrate 20, but the oxide semiconductor layer 30 may be provided on the conductive layer 12 of the electrode substrate 10. In this case, the catalyst layer 15 is provided on the conductive substrate 21 of the counter substrate 20.

  Furthermore, in the first and second embodiments, although the electrode substrate 10 and the counter substrate 20 are connected by the sealing portion 40, a porous member impregnated with the electrolyte 50 between the electrode substrate 10 and the counter substrate 20. In the case where a conductive insulating layer is included, the electrode substrate 10 and the counter substrate 20 may not be connected by the sealing portion 40. In this case, it is preferable to provide an insulating base on the opposite side of the counter substrate 20 to the electrode substrate 10, and join the insulating base and the electrode substrate 10 at the sealing portion.

  Moreover, in the said embodiment, although the photoelectric conversion element 100,200 has one photoelectric conversion cell 60, the photoelectric conversion element 100,200 may be equipped with two or more photoelectric conversion cells 60. FIG. Here, the plurality of photoelectric conversion cells 60 may be connected in series or in parallel.

  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, an ITO / PEN film (manufactured by Pexcel Technologies, Inc.) in which an ITO film was formed on a polyethylene naphthalate film (PEN film) was prepared. Then, a 0.2 mm-thick glass layer (manufactured by Nippon Electric Glass Co., Ltd.) is pasted using an acrylic adhesive that becomes an adhesive layer on the surface opposite to the ITO film of the PEN film in the ITO / PEN film. The Here, as the glass layer, one having flexibility is used. Furthermore, Pt was deposited on the surface of the ITO film by a sputtering method to such an extent that the light transmittance was not significantly impaired. Thus, an electrode substrate serving as a counter electrode was prepared.

  Next, a 50 μm-thick Ti foil was prepared, and a titanium oxide paste containing titanium oxide was applied by screen printing on the Ti foil and dried to form a precursor of the oxide semiconductor layer. Thus, an unfired substrate was obtained. Finally, the unbaked substrate was placed in an oven and fired at 450 ° C. for 1 hour to obtain a porous titanium oxide layer having dimensions of 50 mm × 50 mm × 10 μm. Thus, the working electrode was obtained.

  Next, a dye solution is prepared by dissolving Z907 dye, which is a photosensitizing dye, in a mixed solvent of acetonitrile and t-butyl alcohol at a ratio of 1: 1 (volume ratio) to a concentration of 0.2 mM. did. Then, the working electrode was immersed in this dye solution at normal temperature for 24 hours to adsorb the photosensitizing dye to the porous titanium oxide layer.

  Next, on the working electrode, a cyclic thermoplastic resin sheet made of a trade name "HIMIRAN" (manufactured by Du Pont-Mitsui Polychemicals Co., Ltd.) was disposed. At this time, the porous titanium oxide layer was disposed on the inner side of the annular thermoplastic resin sheet. Then, the thermoplastic resin sheet was heated and melted at 180 ° C. for 5 minutes to be adhered to the working electrode.

On the other hand, an electrolyte was applied to cover the porous titanium oxide layer. At this time, the composition of the electrolyte was as follows.

Iodine (I ₂ ) 0.002 M
Dimethylpropyl imidazolium iodide (DMPImI) 0.6 M
n-Butyl benzimidazole (NBB) 0.1 M
Solvent consisting of 3-methoxypropionitrile (MPN)

  Then, the electrode substrate was placed on the working electrode so as to sandwich the electrolyte with the working electrode, and the sealing portion was heated and melted under reduced pressure (1000 Pa) to bond the electrode substrate and the sealing portion . Thus, one photoelectric conversion cell was obtained. And with respect to this photoelectric conversion cell, the surface on the opposite side to the light-incidence surface (surface of the glass layer in an electrode substrate) was covered with the water blocking package as a back sheet. Thus, a photoelectric conversion element was obtained.

(Example 2)
By setting the thickness of the glass layer to 0.2 mm to 2 mm, a photoelectric conversion element was produced in the same manner as in Example 1 except that the glass layer did not have flexibility.

(Example 3)
The photoelectric conversion element was produced like Example 1 except having used what added the benzotriazole type ultraviolet absorber further to the acrylic adhesive used in Example 1 as an adhesion layer.

(Comparative example 1)
When preparing an electrode substrate, the photoelectric conversion element was produced like Example 1 except not having stuck a glass layer on the surface on the opposite side to ITO of a PEN film in an ITO / PEN film.

<Evaluation of characteristics>
(Long-term durability)
With respect to the photoelectric conversion elements of Examples 1 to 3 and Comparative Example 1 obtained as described above, a heating test was conducted in which they were left at 60 ° C. and 85% RH for 200 hours in the atmosphere. Then, based on the results of the output Pm ₀ measured before the heating test and the output Pm measured after the heating test, the output reduction rate was calculated by the following equation. The results are shown in Table 1.
Power reduction rate = 100 × (Pm _0- Pm) / Pm ₀
The light source, illuminance meter, power source and illuminance used for the output measurement are as follows.

Light source: White LED (Product name "LEL-SL5N-F" manufactured by Toshiba Lighttech Co., Ltd.)
Light meter: Product name "AS ONE LM-331", manufactured by As One Corporation Power supply: Voltage / current generator (product name "ADVANTEST R6246", manufactured by ADVANTEST CORPORATION)
Illumination: 1000 lux

  From the results shown in Table 1, it was found that the photoelectric conversion elements of Examples 1 to 3 have a smaller reduction rate of output than the photoelectric conversion element of Comparative Example 1.

  As mentioned above, according to the photoelectric conversion element of this invention, it was confirmed that long-term durability can be improved.

DESCRIPTION OF SYMBOLS 10 ... Electrode substrate 11 ... Resin film 12 ... Conductive layer 13 ... Adhesion layer 14 ... Glass layer 15 ... Catalyst layer 20 ... Counter substrate 30 ... Oxide semiconductor layer 40 ... Sealing part 50 ... Electrolyte 60 ... Photoelectric conversion cell 100, 200 ... photoelectric conversion element 210 ... back sheet

Claims (2)

At least one photoelectric conversion cell,
The photoelectric conversion cell is
An electrode substrate,
An opposing substrate facing the electrode substrate;
An oxide semiconductor layer provided on the electrode substrate or the counter substrate;
A sealing portion provided so as to surround the oxide semiconductor layer and connecting the electrode substrate and the counter substrate;
An electrolyte provided between the electrode substrate and the counter substrate;
The electrode substrate is
Resin film,
A conductive layer provided on the electrolyte side of the resin film;
A glass layer provided on the side of the resin film opposite to the conductive layer;
Wherein between the resin film and the glass layer, a photoelectric conversion element having an adhesive layer for bonding the resin film and the glass layer,
The electrode substrate further includes a covering portion that covers at least a peripheral portion of the resin film and a peripheral portion of the adhesive layer,
The covering portion is constituted by a part of a back sheet provided so that the counter substrate is disposed between the photoelectric conversion cell and the electrode substrate,
The photoelectric conversion element in which the said back sheet contains a metal layer. The photoelectric conversion element according to claim 1, wherein at least one of the resin film, the adhesive layer, and the glass layer contains an ultraviolet absorber.

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