JP2007265634A - Dye-sensitized solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dye-sensitized solar cell capable of reducing cost and increasing the freedom of a material used for a facing substrate. <P>SOLUTION: By installing an anode 2 in a transparent substrate 4, the use of an expensive material in a facing substrate 5 and the installation of the anode 2 through strict processes are made unnecessary, and cost can be reduced. Since the installation of the anode 2 in the facing substrate 4 is made unnecessary, the use of an optional material is made possible, and the freedom of the material for forming the facing substrate 4 can be increased. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a dye-sensitized solar cell in which a semiconductor layer and an electrolyte layer are provided between two substrates.

  In the dye-sensitized solar cell, a conductive layer is formed on each of two substrates, a semiconductor layer is formed on one of the conductive layers, and between the semiconductor layer and the conductive layer between the two substrates. An electrolyte layer is provided. Such a dye-sensitized solar cell includes a transparent substrate with a transparent conductive film, and a semiconductor electrode and an electrolyte layer in which a dye is supported between the transparent substrate and a conductive substrate as a counter electrode. In a wet solar cell that generates electrical energy between a transparent conductive film and the conductive substrate, the semiconductor electrode is an oxide film obtained by oxidizing at least a part of a metal constituting the conductive substrate. A wet solar cell is disclosed (for example, see Patent Document 1).

Japanese Patent Laid-Open No. 10-112337

  However, the conductive layer is generally formed through a strict process using an expensive material, and the substrate on which the conductive layer is formed is expensive, so that the dye-sensitized solar cell is expensive. It was. Further, since it is necessary to form a conductive layer on the counter substrate, the material used for forming the counter substrate has many restrictions such as a smooth surface.

  The present invention has been made in view of the problems as described above, and is intended to provide a dye-sensitized solar cell that can reduce the cost and has an increased degree of freedom of materials used for the counter substrate. is there.

  In order to achieve the above object, the present invention is configured as follows. That is, a dye-sensitized solar cell according to the present invention includes a transparent substrate, a counter substrate, a photoelectrode layer in which a sensitizing dye is supported on a semiconductor material, an electrolyte layer, and a current collector provided on the transparent substrate. A transparent conductive film also serving as a cathode; and an anode, wherein the photoelectrode layer is formed on the transparent conductive film, and the electrolyte layer is interposed between the photoelectrode layer and the anode. The dye-sensitized solar cell is characterized in that the anode is provided on the transparent substrate.

  According to the dye-sensitized solar cell according to the present invention, since the anode is provided on the transparent substrate, it is not necessary to use an expensive material for the counter substrate and perform an strict process to reduce the cost. can do. Further, since it is not necessary to provide an anode for the counter substrate, any material can be used, and the degree of freedom of the material for forming the counter substrate is increased.

  In addition, it is preferable that the anode is provided on the conductive coating because it is not necessary to provide other means such as a conductive wire to electrically connect the anode and the photoelectrode layer.

  According to the dye-sensitized solar cell according to the present invention, since the anode is provided on the transparent substrate, it is not necessary to use an expensive material for the counter substrate and perform an strict process to reduce the cost. can do. Further, since it is not necessary to provide an anode for the counter substrate, any material can be used, and the degree of freedom of the material for forming the counter substrate is increased.

  BEST MODE FOR CARRYING OUT THE INVENTION The best embodiment according to the present invention will be specifically described below with reference to the drawings.

  FIG. 1 is a longitudinal sectional view showing an embodiment of a dye-sensitized solar cell according to the present invention. The dye-sensitized solar cell 10 includes a transparent substrate 4 made of a cyclic polyolefin resin and a transparent conductive thin film made of ITO (tin-doped indium oxide). The cathode 1 also serves as a current collector. A photoelectrode layer 3 in which a sensitizing dye is supported on a semiconductor layer made of high-quality zinc oxide is formed. On the transparent substrate 4, there is further provided a + electrode 71 that is electrically insulated from the cathode 1 and the photoelectrode layer 3 and formed of ITO (tin-doped indium oxide) for taking out electric power. On the electrode 71, an anode 2 made of platinum, which is also insulated from the cathode 1 and the photoelectrode layer 3, is formed. The + electrode 71 is exposed to the outside from one end of the dye-sensitized solar cell 10, and the − electrode 72 formed continuously to the cathode 1 at the other end and exposed to the outside is exposed to the outside. Electric power can be taken out using the + electrode 71 and the − electrode 72. An electrolyte layer 6 that is an iodine solution is provided between the anode 2 and the photoelectrode layer 3 and the counter substrate 5 made of a cyclic polyolefin resin, and the photoelectrode layer 3 and the anode 2 are interposed between them. Electrons are exchanged through the intervening electrolyte layer 6. The electrolyte layer 6 is sealed with a sealing material 8 provided near both ends between the transparent substrate 4 and the counter substrate 5 so as not to leak.

  Here, in the conventional dye-sensitized solar cell, the + electrode 71 such as ITO is provided over almost the entire surface of the counter electrode 5, and the anode 2 such as platinum is provided over the entire surface of the + electrode 71. Therefore, a lot of very expensive materials such as platinum and ITO are required, resulting in high cost, and it is necessary to apply a large area when forming by vapor deposition or the like, so that the process becomes complicated. Since the photoelectrode layer 3 has a power generation amount proportional to the light receiving area, a large area is required to generate power with high efficiency. However, the anode 2 is connected to the photoelectrode layer 3 via the electrolyte layer 6. A wide area is not required because it is only necessary to exchange electrons, and the function as the anode 2 can be achieved only by providing an extremely small area as shown in the figure. You can also save money.

  Although the cathode 1 and the + electrode 71 may be formed using different materials, a conductive film such as ITO is formed on substantially the entire surface of the transparent substrate 4, and a part of the conductive film is formed on the transparent substrate 4. A transparent substrate 4 provided with the cathode 1 and the anode 2 is very simply provided by forming a scratch to reach with a cutter or the like, and providing the photoelectrode layer 3 on one side and the anode 2 on the other side across the scratch. Can be formed. When the + electrode 71 is formed using a material different from that of the cathode 1, it is necessary to use a transparent conductive film that serves as a current collector and the cathode 1 in order to transmit light to the photoelectrode layer 3. Since the anode 2 does not need to transmit light, it is not necessarily formed of a transparent conductive film, and can be formed using an appropriate conductive material.

  The anode 2 may also serve as the + electrode 71 as shown in FIG. The cathode 1 and the photoelectrode layer 3 are formed leaving a part near the end of the transparent substrate 4, and the anode 2 insulated from the cathode 1 and the photoelectrode layer 3 is formed in a portion where the cathode 1 is not formed. The positive electrode 71 is formed by continuously exposing the anode 2 to the outside. Such a + electrode 71 can save the material forming the + electrode 71 such as ITO, and can directly extract electric power from the material forming the anode 2 such as platinum having a lower electrical resistance than ITO. A decrease in power generation efficiency due to the resistance of the electrode 71 can be suppressed.

  Furthermore, if the counter substrate 5 is translucent, light from both the front and back surfaces of the dye-sensitized solar cell 10 can contribute to power generation in the photoelectrode layer 3 to increase power generation efficiency.

  FIG. 3 is a longitudinal sectional view showing an example of a modification of the dye-sensitized solar cell according to the present invention. First, in the dye-sensitized solar cell 10A at the left end in the figure, a photoelectrode layer 3 is further formed on the cathode 1 formed on the transparent substrate 4 in the same manner as shown in FIG. The layer 3 and the anode 2 are insulated from each other, and electrons can be exchanged between the photoelectrode layer 3 and the anode 2 by the electrolyte layer 6 interposed between the photoelectrode layer 3 and the anode 2. The − electrode 72 is exposed to the outside from one end, but the + electrode 71 on which the anode 2 is formed is not exposed to the outside, and further, the dye-sensitized solar cell 10 </ b> B continuously adjacent on the transparent substrate 4. The cathode 1 is formed. Adjacent dye-sensitized solar cells 10 </ b> A and 10 </ b> B are electrically connected only by the + electrode 71 and the cathode 1 because the electrolyte layer 6 is isolated by the sealing material 8. Further, the positive electrode 71 is continuously formed from the dye-sensitized solar cell 10B to the adjacent dye-sensitized solar cell 10C to form the cathode 1. By sequentially forming a plurality of dye-sensitized solar cells with this structure, the dye-sensitized solar cells 10A to 10D are connected in series, and a high voltage value can be obtained during power generation.

  Normally, the generated current around the integral of the dye-sensitized solar cell 10 is about 0.3 to 0.5 mV, and a plurality of dye-sensitized solar cells 10 are connected in series to obtain a practically required voltage value. However, according to the above-described structure, the pigment in the state of being connected in series by the integral transparent substrate 4 and the counter substrate 5 has been generated. The sensitized solar cell 10 can be formed, no work related to connection is required, and there is no problem of strength because there is no connection portion as a joint.

  FIG. 4 is a longitudinal sectional view showing an example of connection between dye-sensitized solar cells of the dye-sensitized solar cell according to the present invention. The dye-sensitized solar cell 10 to be connected may be a single one as shown in FIG. 1 or may be in a series state as shown in FIG. 3 to obtain a desired voltage value. It shows a connection. First, as shown in (a), a plurality of dye-sensitized solar cells 10 are arranged such that the upper side is the transparent substrate 4, and the gap between the end portions of the + electrode 71 and the − electrode 72 is electrically connected by the conductor E. Connected. (B) shows the exposed + electrode 71 of the dye-sensitized solar cell 10A arranged so that the upper side becomes the transparent substrate 4, and the dye-sensitized solar cell arranged so that the transparent substrate 4 becomes lower side. The exposed −electrode 72 of 10B is superposed in the vertical direction, and a conductor E is provided between the + electrode 71 and the −electrode 72 to be electrically connected. The counter substrate 5 of the dye-sensitized solar cell 10B is transparent, and light incident from above passes through the counter substrate 5 and the electrolyte layer 6 and enters the photoelectrode layer 3. With this structure, the contact area between the positive electrode 71 and the negative electrode 72 and the conductor E can be increased to ensure conductivity, and the strength of the connection portion is not limited to the conductor E, but the transparent substrate 4 and the counter substrate 5. By supporting by, the intensity | strength of a connection part can be raised.

  As a material used for forming the transparent substrate 4, highly transparent glass, tempered glass, or a highly transparent synthetic resin such as polycarbonate resin, acrylic resin, polyarylate resin, polymethacrylate, or polyvinyl chloride may be used. it can. The counter substrate 5 can be formed by using an appropriate material when transparency is not required, but the materials listed in the transparent substrate 4 are preferably used when transparency is required. be able to. In addition to the highly durable polyethylene terephthalate resin for the electrolyte solution used for the electrolyte layer 6, polyester synthetic resins such as polybutylene terephthalate resin and polyethylene naphthalate resin, and polyolefin-based synthetic resins such as polyethylene, polypropylene, and cyclic polyolefin resins are also suitable. Can be used.

  As for the transparent conductive film forming the cathode 1, tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), gold, platinum, etc., which have excellent transparency and high conductivity, and combinations thereof are used. It is formed on the transparent substrate 4 by an appropriate method such as a vacuum deposition method, a sputter deposition method, an ion plating method, a CVD method, or an electrophoretic electrodeposition method, or a film on which these thin films are formed is attached to the transparent substrate 4 It can be formed by wearing or the like.

  The anode 2 is made of platinum, carbon, a conductive polymer, a metal oxide such as tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), or the like, and a composite material of the above-described substances, and causes a potential difference from the cathode 1. Using the material, it is formed on the conductive film or the transparent substrate 4 by an appropriate method such as a vacuum deposition method, a sputter deposition method, an ion plating method, a CVD method, an electrophoretic deposition method, or a thin film thereof is formed. The formed film can be formed by sticking to the transparent substrate 4 or the like.

  Further, it is preferable that the + electrode 71 and the − electrode 72 are formed separately from the cathode 1 and the anode 2 as shown in the above-described embodiment, but it is preferable that the + electrode 71 and the − electrode 72 are formed separately. It can be formed using an appropriate conductor.

The photoelectrode layer 3 is Fe ₂ O ₃ , Cu ₂ O, In ₂ O ₃ , WO ₃ , Fe ₂ TiO ₃ , PbO, V ₂ O ₅ , FeTiO ₃ , Bi ₂ O ₃ , Nb ₂ O ₃ , SrTiO _3. , ZnO, BaTiO ₃ , CaTiO ₃ , KTaO ₃ , SnO ₂ , ZrO _2, etc., can be formed by supporting a sensitizing dye on a thin film formed using a semiconductor material such as a semiconductor material. Titanium oxide (TiO ₂ ) or zinc oxide (ZnO) that is excellent in formability of a transparent thin layer and can be electrodeposited is preferable from the viewpoint of workability and the like, but is not limited thereto and is appropriate. Can be used.

  The electrolyte layer 6 includes a liquid electrolyte such as a mixed solution of acetonitrile and ethylene carbonate, a solvent such as methoxypropionitrile and an electrolyte such as lithium iodide and metallic iodine, a polymer gel electrolyte, and the like. Liquid electrolyte systems such as quasi-solidified electrolytes, solid electrolyte systems such as p-type semiconductors and hole transport agents can be used.

  The sealing material 8 is not particularly limited as long as it can prevent leakage of the electrolyte layer 42, but a sealing material such as silicone resin can be suitably used. Further, a ring-shaped synthetic resin having elasticity such as rubber or elastomer may be used.

  Furthermore, the conductor E is not particularly limited as long as it is a conductive material, and a metal material having a low electric resistance value can be suitably used. In addition, by using a conductive adhesive, the + electrode 71 and the-electrode 72 can be electrically connected, and adhesion between the dye-sensitized solar cells can be performed at the same time. This is preferable.

It is a longitudinal cross-sectional view which shows one Embodiment of the dye-sensitized solar cell concerning this invention. It is a longitudinal cross-sectional view which shows an example of a deformation | transformation of an anode of the dye-sensitized solar cell concerning this invention. It is a longitudinal cross-sectional view which shows an example of a deformation | transformation of the dye-sensitized solar cell concerning this invention. It is a longitudinal cross-sectional view which shows the example of a connection between the dye-sensitized solar cells concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cathode 2 Anode 3 Photoelectrode layer 4 Transparent substrate 5 Counter substrate 6 Electrolyte layer 10 Dye-sensitized solar cell

Claims (2)

A transparent substrate, a counter substrate, a photoelectrode layer in which a sensitizing dye is supported on a semiconductor material, an electrolyte layer, a transparent conductive film provided on the transparent substrate and serving as a current collector and a cathode, and an anode A dye-sensitized solar cell in which the photoelectrode layer is formed on the transparent conductive film, and the electrolyte layer is interposed between the photoelectrode layer and the anode, A dye-sensitized solar cell provided on the transparent substrate. The dye-sensitized solar cell according to claim 1, wherein the anode is provided on the conductive film.

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