JP2005216505A - Dye-sensitized solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dye-sensitized solar cell having weather resistance preventing deterioration for a long time. <P>SOLUTION: The dye-sensitized solar cell comprises at least an adhesive layer, facing electrodes comprising a base material layer and a transparent electrode layer, a charge transport layer, a photoelectrode comprising a metal oxide semiconductor layer carried with dye, a transparent electrode and a base material layer, an adhesive layer, and a transparent protection layer formed on a substrate in this order. An ultraviolet ray absorber comprising a metal oxide and/or a light stabilizer are/is added to the base material layer of the photoelectrode, and the ultraviolet ray absorber comprising the metal oxide and/or the light stabilizer are/is added to the transparent protection layer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In the present invention, an ultraviolet absorber made of a metal oxide is added to a thermoplastic resin layer among dye-sensitized solar cells that absorb light and convert it into electricity by a sensitizing dye adsorbed on a metal oxide semiconductor. The present invention relates to a dye-sensitized solar cell with improved weather resistance.

  Conventionally, single crystal silicon solar cells, amorphous silicon solar cells, and compound semiconductor solar cells have been known as solar cells. However, a large amount of energy such as electric energy is consumed to produce silicon single crystals and amorphous silicon. Therefore, the cost was high. On the other hand, it is known that a dye-sensitized solar cell using an electrode configured by holding a dye on a semiconductor surface has low cost and high conversion efficiency. A dye-sensitized solar cell using a plastic film as a base material is also known.

  However, there has been no large-sized dye-sensitized solar cell made of a material that is flexible, lightweight, and hardly uses harmful substances. There was also no dye-sensitized solar cell made of a rigid body made of a material that is light and uses almost no harmful substances.

  The configuration of the dye-sensitized battery is as follows. For the photoelectrode, a porous metal oxide semiconductor obtained by applying a metal oxide semiconductor sol on a transparent conductive film and drying is usually used for the electrode. Furthermore, by immersing these metal oxide semiconductor electrodes in a solution in which the dye is dissolved, a photoelectrode is manufactured by forming a dye layer by adsorbing a single molecule of the dye on the porous metal oxide semiconductor surface. The Further, after forming a transparent or opaque conductive film and / or a conductive film as a catalyst as a counter electrode, a dye-sensitized solar cell is manufactured by sandwiching a photoelectrode and a counter electrode through a charge transport layer.

  The operating principle of the dye-sensitized solar cell is as follows. Light incident from the photoelectrode side is absorbed by the transparent conductive film and the dye supported on the surface of the metal oxide semiconductor, and the sensitizing dye that has absorbed the light is excited. The excited dye quickly passes electrons to the metal oxide semiconductor, and the electrons travel through the metal oxide semiconductor and flow to the transparent conductive film. After emitting electrons, the positively charged dye returns to neutral by receiving electrons from the charge transport layer. As described above, the dye-sensitized solar cell operates with the photoelectrode as the negative electrode and the counter electrode as the positive electrode.

In the charge transport layer, an electrolyte in which iodine and lithium iodide or potassium iodide are dissolved in an organic solvent such as acetonitrile is generally used. In the case of using a liquid, sealing for preventing liquid leakage is important from the viewpoint of the environment at the time of destruction and the lifetime of the solar cell, but it is difficult to maintain the sealing over a long period of time. Therefore, in recent years, a dye-sensitized solar cell using a polymer gel that does not cause a spill is proposed.
Japanese Patent No. 2664194 Japanese Patent Laid-Open No. 2003-3272 JP 2001-210390

  In view of the above, the problem to be solved by the present invention is to provide a dye-sensitized solar cell having weather resistance that does not deteriorate over a long period of time.

  The present invention has been made in order to solve the above-mentioned problems. That is, the invention according to claim 1 is that at least an adhesive layer on a substrate, a counter electrode comprising a base material layer and a transparent electrode layer, a charge transport layer, In the dye-sensitized solar cell in which a photoelectrode comprising a metal oxide semiconductor layer, a transparent electrode layer, and a base material layer in which a dye is held, an adhesive layer, and a transparent protective layer are provided in this order, the base material of the photoelectrode A dye-sensitized solar cell comprising an ultraviolet absorber and / or a light stabilizer made of a metal oxide in a layer, and the invention according to claim 2 is characterized in that the transparent protective layer is made of a metal oxide. The dye-sensitized solar cell is characterized by adding an ultraviolet absorber and / or a light stabilizer.

  Since the dye-sensitized solar cell of the present invention uses a metal oxide UV absorber, the weather resistance is increased because the deterioration of the bleed and UV absorber is less than that of the organic UV absorber.

  In FIG. 1, the structure of the cross section of one Example of the dye-sensitized solar cell of this invention is shown. In this example, the dye-sensitized solar cell 16 has an adhesive layer 2, a counter electrode 18, a charge transport layer 7, a photoelectrode 17, an adhesive layer 11, a transparent protective film 12, a transparent protective layer, an anti-protection layer on the support substrate 1. The dirty layer 14 is formed in this order.

  The photoelectrode 17 is composed of a base material layer 10, a transparent electrode layer 9, and a metal oxide semiconductor layer 8 in which a pigment is held from the surface side. The counter electrode 18 includes the transparent electrode layer 6 and the base material layer 5 from the surface side.

  Although the aluminum plate etc. can be used as the support substrate 1 in this invention, it is not specifically limited to these.

  As the adhesive used in the adhesive layers 2, 11 and the like in the present invention, it can be appropriately used as long as it has adhesiveness between layers and has transparency, and preferably has few harmful substances. Most suitable is a two-component curable urethane resin.

  The material used for the base material layers 5 and 10 used in the present invention is a thermoplastic resin film having insulation and transparency, such as polyethylene terephthalate, polypropylene, polymethyl methacrylate, polycarbonate, polystyrene, polyethylene sulfide, polyether sulfide. Polyether sulfone, polyethylene naphthalate, triacetyl cellulose, polyphenylene ether, and the like can be used. In particular, a polyester resin and a polyolefin resin with weather resistance and heat resistance are preferable from the viewpoint of the environment in which the solar cell is used and the life span, and a polyolefin resin is most suitable, and the most suitable is a composite resin film composed of an appropriately blended polyester resin and polyolefin resin. is there.

  As the transparent electrode layers 6 and 9 in the present invention, tin oxide, zinc oxide doped with fluorine, indium or the like, and other conductive transparent conductors with little absorption in the visible light region are preferable. The transparent electrode layers 6 and 9 can be formed by a vacuum conductive film (ITO) formed by a vacuum film forming process such as a vacuum vapor deposition method, a reactive vapor deposition method, an ion beam assist method, an ion plating method, or a plasma CVD (Chemical vapor deposition) method. The layer (indium / tin oxide) can be used, but is not particularly limited to this, and any film forming method may be used.

  As a method for forming the metal oxide semiconductor layer 8 of the metal oxide semiconductor layer 8 holding the pigment, a vacuum deposition method using a metal, a metal oxide, a metal suboxide, a reactive deposition method, an ion plating method, or the like. , Ion beam assisted deposition, sputtering, reactive sputtering, plasma CVD using metal halide, quinzoku alkoxide, or other vacuum deposition methods can be used. Further, by disposing the thermoplastic resin layer obliquely with respect to the evaporation surface or the target surface, the porosity is increased and the actual surface area relative to the projected area can be increased. Further, the metal oxide semiconductor layer 8 of the metal oxide semiconductor layer 8 in which the pigment is held may be subjected to plasma treatment, corona treatment, UV treatment, acid or base treatment, or other post-treatments.

  As the dye of the metal oxide semiconductor layer 8 in which the dye is held in the present invention, any dye can be selected as long as it absorbs light capable of generating an electromotive force. Such dyes include, for example, ruthenium-tris, ruthenium-bis, osmium-tris, osmium-bis type transition metal complexes, or ruthenium-cis-diaqua-bipyridyl complexes, or phthalocyanines, porphines, dithiolate complexes, acetyl acetate complexes. And so-called metal chelate complexes, and organic dyes such as cyanidin dyes, merocyanine dyes, and rhodamine dyes, and oxadiazole derivatives, benzothiazole derivatives, coumarin derivatives, stilbene derivatives, aromatic organic compounds, and others are preferable. These dyes desirably have a large extinction coefficient and are stable against repeated redox. The dye is preferably chemically adsorbed on the metal oxide semiconductor and has a functional group such as a carboxyl group, a sulfonic acid group, a phosphoric acid group, an amide group, an amino group, a carbonyl group, or a phosphine group. preferable. It is preferable that several such functional groups are present in the dye molecule.

  The holding of the dye of the metal oxide semiconductor layer 8 having the dye held by the present invention to the metal oxide semiconductor is prepared by preparing a dye solution in which the dye is dissolved in an aqueous solvent or an organic solvent by the dye used, A metal oxide semiconductor is immersed in the dye solution. After a sufficient time has elapsed for the dye to be adsorbed to the metal oxide semiconductor, the metal oxide semiconductor can be lifted from the dye solution, washed, and dried. If necessary, when the metal oxide semiconductor is immersed in the dye solution, it may be heated, or the dye solution may be acidic or basic.

  As the electrolyte to be contained in the charge transport layer 7 of the present invention, generally, materials used for the charge transport layer 7 of the dye-sensitized battery can be arbitrarily used. For example, iodide containing iodine, bromide, quinone complex, tetra Cyanoquinodimethane (TCNQ) complexes, dicyanoquinone diimine complexes, and others are preferred.

  Moreover, as an electrolyte contained in the charge transport layer 7 of the present invention, a solid charge transport layer including a solid electrolyte or a p-type semiconductor can be used. Such a charge transport layer is preferable because there is no possibility of liquid leakage that may occur when a liquid charge transport layer is used.

  Specific examples of materials that can be used for the charge transport layer 7 include, as donor skeletons, aromatic amine compounds such as triphenylamine, diphenylamine, and phenylenediamine, condensed polycyclic hydrocarbons such as naphthalene, anthracene, and pyrene, and azobenzene. Examples include azo compounds, compounds having a structure in which aromatic rings such as stilbene are linked by an ethyl bond or acetylene bond, amino group-substituted heteroaromatic ring compounds, porphyrins, phthalocyanines, etc., and acceptor skeletons are quinones, Examples include tetracyanoquinodimethanes, dicyanoquinone diimines, tetracyanoethylene, viologens, and dithiol metal complexes. Other materials that can be used for the solid charge transport layer include CuI, AgI, TiI, other metal iodides, and CuBr. Further, iodides, quinone complexes and the like may be conjugated to a polymer gel such as polyalkylene ether. These materials can be used in any combination as required.

  The method for forming the charge transport layer 7 in the present invention includes dipping, spin coater, bar coater, blade coater, knife coater, reverse roll coater, gravure roll coater, squeeze coater, curtain coater, spray coater, die coater, and gravure reverse coater. However, a method capable of continuous coating is more preferable. In the case of using a solid electrolyte or a p-type semiconductor, after making a solution using an arbitrary solvent, coating is performed using the above method, and the solvent is evaporated by heating the thermoplastic resin layer 5 to an arbitrary temperature. To form.

  As the transparent protective layer in the present invention, a resin may be appropriately selected in consideration of weather resistance, stain resistance, etc., and the transparent protective layer 12 and the transparent protective layer 13 are provided as in this embodiment. Although it is preferable to make two layers depending on the properties. As the transparent protective film layer 12 of the present embodiment, fluorine, acrylic, polypropylene, polyethylene terephthalate, fluorine resin, polymethyl methacrylate resin, and the like can be used, but are not particularly limited thereto.

  Moreover, as the transparent protective layer 13 of a present Example, although 2 liquid curable acrylic urethane resin etc. can be used, it is not specifically limited to these.

As the antifouling layer 14 in the present invention, a layer made of a two-component curable silicone-modified acrylic resin can be used.
As the ultraviolet absorber and / or light stabilizer composed of a metal oxide to be added to the base material layer and / or the transparent protective layer in the present invention, zinc oxide, fine powder of tin oxide, etc. are desirable, but are not particularly limited thereto. It can be used as long as it is made of a metal oxide and exhibits a desired effect.

  As the transparent electrode layers 6 and 9 in the present invention, tin oxide, zinc oxide doped with fluorine, indium or the like, and other conductive transparent conductors with little absorption in the visible light region are preferable, but are not particularly limited thereto. It can be used if it exhibits a desired effect.

  The dye-sensitized solar cell 16 having the layer configuration of FIG. 1 was produced as follows. The photoelectrode 17 has a roll-shaped polyethylene terephthalate having a thickness of 100 μm (opposite of vacuum sputtering in advance) by adding 1 part of a metal oxide ultraviolet absorber to 100 parts of the base resin to the base material layer 10 of a flexible material. On the side, an antifouling layer (two-component modified silicone acrylic resin coating layer) was used, on which indium tin oxide (ITO) was continuously formed as a transparent electrode layer 9 by a vacuum sputtering method. Titanium oxide was continuously applied as the metal oxide semiconductor layer 8 and then formed by in-line drying using a dryer at 120 ° C. As a raw material for titanium oxide, titanium tetra-t-butoxide was hydrolyzed with nitric acid. The titanium oxide sol was synthesized using the sol-gel method, and the obtained titanium oxide sol was used. The obtained laminate was in-line and continuously immersed in an ethanol solution of bis (4,4-dicarboxy-2,2-bipyridyl) dithiocyanate ruthenium, whereby bis (4,4-dicarboxy- 2,2-bipyridyl) dithiocyanate ruthenium was held, followed by washing with water and ethanol, and drying to obtain a photoelectrode 17. Subsequently, 0.5 MliI, 0.05 MI2, methoxy as the charge transport layer 7 was obtained. A gel electrolyte composed of acetonyl and polyethylene glycol was formed on the photoelectrode 17 by roll-to-roll spray coating.

  As the counter electrode 18, a roll-shaped polyethylene terephthalate having a thickness of 100 μm was used as the flexible substrate 5. On this, indium tin oxide (ITO) was continuously formed as a transparent electrode layer 6 by vacuum sputtering. Next, lamination was performed such that the film-forming surfaces face each other, and the side surfaces were sealed with an epoxy adhesive to produce a dye-sensitized solar cell.

  Next, E60L (made by Toray Industries, Inc.) having a thickness of 188 μm in white polyethylene terephthalate resin is coated with an ultraviolet absorbent added two-component acrylic urethane resin, and then the coated surface and the side opposite to the transparent electrode layer 6 of the flexible base material layer 5 Were laminated with a two-component polycarbonate adhesive. Next, the support substrate (aluminum plate) 1 was laminated with a two-component polycarbonate adhesive.

  A dye-sensitized solar cell was produced in the same manner as in Example 1 except that the flexible base materials 10 and 5 of Example 1 were changed to polypropylene resin.

Comparative Example 1

  A dye-sensitized solar cell was produced in the same manner as in Example 1 except that the inorganic ultraviolet absorber was removed from the flexible base materials 10 and 5 of Example 1.

Comparative Example 2

A dye-sensitized solar cell was produced in the same manner as in Example 1 except that the inorganic ultraviolet absorber was removed from the flexible base materials 10 and 5 of Example 2.
<Performance evaluation>
Metal halide lamp type testing machine JTM G 01 2000 Japan Testing Machine Industry Association Standard JTM STANDARD Metal halide Lamp type appa ratus
Daipla Metal Weather (KU-R5DCI-A) (Daipla Wintes Co., Ltd.)
Light source lamp: MW-60W, filter: KF-1 (295 nm to 780 nm)
Condition: Illuminance 65 ± 3 mW / square cm (measurement range from 330 nm to 390 nm)
Light (irradiation) (53 ° C., 70% RH) 20 hours, Dew (dark condensation) (30 ° C., 95% RH) 4 hours, Rest (rest) (30 ° C., 95% RH) 0.01 hours. Shower is 30 seconds before and after Dew.

  The above 24.01 hours were defined as one cycle, and four cycles were performed.

  In addition, as for pure water b) and c), the city water of Sakai City was used as pure water having a conductivity of 2 μS / cm or less by the following apparatus.

Pure water production machine is Kurita Kogyo Co., Ltd., residual chlorine remover: Carbonator CF50, water softener: KS-MA-28J, reverse osmosis membrane device: Mac Ace KN-600 type, continuous deionizer: Pure Ace PA-240X type <Test results>
Evaluation criteria Pigment fading appearance, coating layer deterioration (whitening, cracks, etc.), overlay layer and base film layer deterioration (peeling), and color difference meter CR-200 (Minolta Camera Co., Ltd., aperture 8 mm JIS Z8729 L * a) * B * color system) and measured with a D65 light source.
As a result, there was no problem in Examples 1 and 2, but the appearances of Comparative Examples 1 and 2 were fading and yellowing.

  The dye-sensitized solar cell of the present invention can be used particularly on the back side of large outdoor displays, houses, apartments, condominiums, factory rooftops and the like because of its weather resistance.

It is explanatory drawing which shows the structure of the cross section of the dye-sensitized solar cell in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Support base material 2 ... Adhesive layer 5 ... Base material layer 6 ... Transparent electrode layer 7 ... Charge transport layer 8 ... Metal oxide semiconductor layer 9 in which the pigment | dye was held up ... Transparent electrode layer 10 ... Base material layer 11 ... Adhesive layer 12 ... Transparent protective film layer 13 ... Transparent protective layer 14 ... Antifouling layer 15 ... Electron 16 ... Dye-sensitized solar cell 17 ... Photoelectrode 18 ... Counter electrode

Claims (2)

  At least an adhesive layer on a substrate, a counter electrode consisting of a base material layer and a transparent electrode layer, a charge transport layer, a metal oxide semiconductor layer holding a pigment, a photoelectrode consisting of a transparent electrode layer and a base material layer, and an adhesive In a dye-sensitized solar cell in which a layer and a transparent protective layer are provided in this order, an ultraviolet absorber made of a metal oxide and / or a light stabilizer is added to the base layer of the photoelectrode. Dye-sensitized solar cell.   A dye-sensitized solar cell obtained by adding an ultraviolet absorber and / or a light stabilizer made of a metal oxide to the transparent protective layer.

Images