JP4651347B2 - Photoelectric conversion device and photovoltaic device using the same - Google Patents

Description

  The present invention relates to a photoelectric conversion device such as a dye-sensitized solar cell excellent in long-term reliability and productivity, and a photovoltaic device using the photoelectric conversion device.

  In recent years, a dye-sensitized solar cell that can obtain high conversion efficiency from light energy to electric energy by using a semiconductor such as titanium oxide carrying a dye has been attracting attention.

The structure of this type of solar cell is, for example, provided on a transparent conductive layer formed on the surface of a transparent substrate in a state where a semiconductor carrying a pigment is placed in an electrolyte layer containing iodine, and platinum or the like is formed on the electrolyte layer. Is provided on the lower surface, and the electrolyte layer is covered with a sealing material. With this structure, when sunlight enters from a transparent substrate, the dye absorbs light energy, emits electrons to the semiconductor by charge separation, and delivers the electrons to the transparent conductive layer. On the other hand, in the vicinity of the interface of the conductive substrate of the counter electrode, an electrical energy is taken out by an I ⁻ / I ₃ ⁻ redox reaction.

  In general, in a solar cell, it is necessary to ensure a long-term reliability of 10 years or more, and it depends on a solvent of an electrolyte layer (including an electrolyte, a solvent, an additive, etc.) that is a constituent member of the dye-sensitized solar cell. Prevents dissolution of the sealing material, prevents leakage of the solvent from the sealing material, suppresses moisture, oxygen, etc. in the air from entering the electrolyte layer. High safety is demanded by absorbing the impact caused by the damage and suppressing the destruction.

  In particular, when a halogen-based electrolyte containing iodine or the like is used, it is highly corrosive, so that the sealing material for the electrolyte layer is required to have corrosion resistance against halogen. In addition, under conditions where oxygen enters a halogen-based electrolyte and oxygen and light coexist, the dye is liable to oxidize and deteriorate, leading to a decrease in conversion efficiency. Therefore, a barrier property against oxygen is necessary. When water enters the electrolyte, active oxygen is formed from water on the surface of the porous semiconductor, thereby degrading the dye and reducing the conversion efficiency. Further, in the case of a halogen-based electrolyte, in particular, adhesion between the substrate and the sealing material, adhesion between the electrode and the sealing material, weather resistance, and the like are required.

For example, a film-like ionomer resin is used as a sealing material for the electrolyte layer (see Patent Document 1), an epoxy resin, an epoxy resin containing insulating fine particles, and a silicone resin (refer to Patent Document 2). Reference), silicone rubber, silicone resin, thermosetting or photo-curable epoxy resin, and fluorine resin (see Patent Document 3), and epoxy resin that is difficult to dissolve in a solvent (Patent Document) 4), use of glass frit (see Patent Document 5), and use of polyisobutylene resin (see Patent Document 6) have been proposed.
JP 2003-331935 A Japanese Patent Laid-Open No. 11-307141 JP 2000-30767 JP 2000-150005 A Japanese Patent Laid-Open No. 2001-185244 Japanese Patent Laid-Open No. 2002-313443

  However, in the formation of a sealing material for solar cells, when a film-like ionomer resin is used, it is necessary to heat the entire substrate when thermocompression bonding the substrates to be electrodes, and for this reason, a large area soaking A heater and a large-sized crimping device are required, the equipment becomes large-scale, and a long sealing time is required. This causes thermal degradation of the dye, and thus labor and time are required to suppress it as much as possible. In addition, since the sealing material is in the form of a film, thermal shrinkage is large, and further, gap variation between substrates and adhesion are reduced, thereby reducing product yield.

  Also, when using epoxy resin or silicone resin as the sealing material, the durability is not sufficient for long-term use over several years under outdoor conditions, so dissolution of the sealing material by the solvent that constitutes the electrolyte layer It is difficult to prevent the leakage of the solvent from the sealing material, and to prevent the moisture, oxygen, etc. in the air from entering the electrolyte layer.

  In addition, when epoxy resin, silicone resin, and polyisobutylene resin, which are thermosetting resins, are used as the sealant, if the reactant comes into contact with a highly corrosive electrolyte layer before curing, reliability is reduced due to insufficient curing. Decreases.

  In addition, when a thermoplastic fluorine-based resin is used as the sealing material, the adhesion is poor and leakage of the electrolyte layer cannot be prevented. In addition, since intrusion of moisture, oxygen and the like in the air cannot be suppressed, a long-term highly reliable solar cell cannot be obtained after all.

  In addition, when glass frit is used, an operation of 400 ° C. or higher is necessary to fuse it to the substrate.For example, it is impossible to seal after forming a semiconductor layer carrying a dye for a long time. Become.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a photoelectric conversion device that has long-term reliability in sealing of a conventional electrolyte layer, can be easily manufactured, and has excellent productivity. It is to provide a photovoltaic device.

In order to achieve the above object, in the photoelectric conversion device of the present invention, a first base whose one main surface is one electrode and a second base whose one main surface is the other electrode are the one electrode and the other electrode. are arranged so as to face the door, becomes with intervening electrolytic electrolyte layer between the first substrate and the second substrate, an electron-transporting material having a dye for photoelectric conversion to the one on the electrodes are provided In the photoelectric conversion device, a hot melt resin is formed in a region extending from the side surface of one of the first substrate and the second substrate to the outer peripheral portion of the electrolyte layer and extending to the one main surface of the other substrate. However, it is applied so that the thickness in the direction parallel to the side surface decreases as the distance from the one substrate increases.

  The photovoltaic power generation means of the present invention is characterized in that the photoelectric conversion device is used as a power generation means, and the generated power of the power generation means is supplied to a load.

According to the photoelectric conversion device of the present invention, the result with intervening electrolytic electrolyte layer between the first substrate and the second substrate, an electron-transporting material having a dye for photoelectric conversion to the one on the electrode is provided In the region extending from the side surface of one of the first substrate and the second substrate to the outer peripheral portion of the electrolyte layer and extending to the one main surface of the other substrate , the hot melt resin is Since the thickness in the direction parallel to the side surface is applied so as to decrease as the distance from the one substrate increases, even if the electrolyte layer is made of a highly reactive material containing halogen such as iodine, oxygen Since no substances such as water and water are mixed in the electrolyte layer, a photoelectric conversion device capable of sealing with extremely high durability and weather resistance can be provided.

  In addition, since the hot melt resin has few reactive substituents and high gas barrier properties, volatilization of the electrolyte and solvent in the electrolyte layer can be suppressed, and as a result, a photoelectric conversion device having excellent weather resistance can be provided.

  Furthermore, since only the hot melt resin is heated and melted and applied, sealing can be easily performed, so that the necessary amount of the hot melt resin can be used and the first substrate and the second substrate are deformed so as to be deformed. In addition, it is possible to provide a highly reliable photoelectric conversion device with high productivity.

  When a reactive sealing material such as a thermosetting type such as an epoxy resin or a silicone resin of a conventional example is cured, the reactive sealing material comes into contact with a highly reactive electrolyte layer, and the sealing material component is Although there is a case where the reaction does not occur or the reaction product of the sealing material deteriorates and the durability is lowered, there is no such concern in the case of the present invention. In addition, the reactive resin has many reactive substituents such as —OH group, —CO— group, —NH— group, —CN group, —OCO— group, —COOR— group even after curing is completed. Therefore, the reactive sealing material is easily swollen by the electrolyte component or is easily attacked by the highly reactive electrolyte layer.

  For example, when the dye is first adsorbed or bonded to the semiconductor layer and then the hot melt resin is applied to the peripheral edge of the substrate and the substrate is sealed, the portion that comes into contact with the hot melt resin (hot melt applicator or hot melt resin) Since only the tip of the gun and the container) need to be heated, there is no deterioration of the dye or the electrolyte layer. In addition, since it is not necessary to heat a large substrate, the manufacturing cost can be reduced.

  In addition, when a hot melt resin is first applied to the peripheral edge of the base and the gap between the bases is sealed, and then the dye is adsorbed or bonded to the semiconductor layer, the hot melt resin is first applied to the base by a hot melt applicator or printing. Apply by etc. Thereafter, the opposing substrates are heated and pressure bonded to seal and bond the substrates together. Thereafter, a dye is injected from the injection port of the substrate, and the dye is adsorbed on the semiconductor layer. Thereafter, a solvent is injected from the injection port, and excess dye is washed. Thereafter, the semiconductor layer is dried. Thereafter, an electrolyte layer component is further injected. Thereafter, the inlet is coated and sealed using a hot melt resin. Thereby, a pigment | dye is not heated and a pigment | dye is not deteriorated.

  Moreover, since hot melt resin has few reactive substituents, the sealing property fall by the electrolyte layer with high reactivity does not occur.

  The sealing material comprising the coating type hot melt resin of the present invention is a resin film having an oxygen barrier property on the side in contact with the electrolyte layer, such as an ethylene-vinyl alcohol copolymer resin, an ethylene-vinyl acetate copolymer resin, An ethylene-vinyl acetate-vinyl chloride copolymer resin or an ionomer resin is used. These resins have dense polymer chain gaps and suppressed thermal vibration (segment motion), so the gas diffusion coefficient is low, and there is a strong interaction of hydrogen bonds between polymer chains, and segment motion is constrained. (However, hydrogen bonds are weak in water because they break in the presence of water).

  Further, a resin having a water vapor barrier property (for example, polyvinylidene chloride, polypropylene) or an inorganic film (for example, a function-separated multilayer structure made of silica, aluminum, or the like) is used on the side in contact with the outside. These materials have relatively large atoms and molecules such as chlorine in the polymer side chains filling the polymer chain gaps and do not have hydrogen bond substituents. As a result, the gas barrier properties of the electrolyte, solvent, and additive that are the volatile components of the electrolyte layer (weak gas barrier property against water) against the electrolyte layer containing no solvent but containing solvent and the outside environment containing no solvent but containing water ) Resin with high ethylene-vinyl alcohol copolymer resin, ethylene-vinyl acetate copolymer resin, ethylene-vinyl acetate-vinyl chloride copolymer resin, or ionomer resin is provided on the electrolyte layer side, affecting water By providing polyvinylidene chloride, which is a resin that has a high gas barrier property, or polypropylene on the outside, and sealing the substrates, it is not necessary to heat the substrates at the time of sealing, without deteriorating the dye, The long-term reliability of the dye-sensitized solar cell can be improved.

  Thus, by combining both advantages by laminating, a high-performance barrier property that neither permeates water nor oxygen can be obtained.

  When used as a sealing material for the coating-type hot melt resin of the present invention, the hot melt resin and a film having a water vapor barrier property may be used in an overlapping manner. For example, an ethylene-vinyl acetate copolymer resin, which is a hot-melt resin, is sealed with a sealing material in which a metal film such as an aluminum alloy or a laminated metal film made of an inorganic film such as silica is laminated. Can be stopped. Thereby, the volatile component of an electrolyte layer can be suppressed and the long-term reliability of a dye-sensitized solar cell can be improved.

  Hereinafter, a photoelectric conversion device of the present invention and a photovoltaic device using the photoelectric conversion device will be described in detail with reference to the drawings schematically shown.

  FIG. 1 shows a schematic cross-sectional view of a dye-sensitized solar cell which is a photoelectric conversion device of the present invention. As shown in FIG. 1, this dye-sensitized solar cell has a first base whose one main surface is the first conductive film 2 of one electrode, and a first base whose second main surface is the second conductive film 4 of the other electrode. Two substrates. In this embodiment, a first base body in which the first conductive film 2 as one electrode is formed on one main surface of the first substrate 1, and the second conductive film 4 as the other electrode is one main surface of the second substrate 3. And a second substrate formed on the substrate. In addition, while the first conductive film 2 and the second conductive film 4 face each other, an electrolyte layer 6 containing an electron transporter 5 having a dye that performs photoelectric conversion is interposed. Further, the region extending from the first base to the outer periphery of the electrolyte layer 6, the outer periphery of the electrolyte layer 6 and the region extending from the second base to the outer periphery of the electrolyte layer 6 prevent permeation of components, oxygen and water of the electrolyte layer 6. It is applied with a sealing material 7 made of hot melt resin.

  Here, the first substrate 1 is a transparent substrate provided on the light incident side, and examples thereof include blue plate glass and white glass. However, the first substrate 1 is not limited to these, and various resins (PET (polyethylene terephthalate) are used. Or PEN (polyethylene naphthalate)). Alternatively, the first substrate 1 itself may constitute one electrode, and the first substrate itself may be the one electrode. In this case, the entire first base is made of the same material as that of the first conductive film 2, and for example, the whole may be made of the same conductive material.

  In addition, the first conductive film 2 or the second conductive film 4 in the case of transmitting light is made of a transparent material such as tin oxide (FTO), tin-doped indium oxide (ITO) or zinc oxide doped with an appropriate amount of fluorine. However, it is not limited to these materials. In particular, the transparent second conductive film 4 is preferably a transparent conductive film to which platinum, carbon or the like, which is a reduction catalyst for the electrolyte layer 6, is attached because the reduction efficiency of the electrolyte layer 6 can be improved.

  In order to prevent the second conductive film 4 from transmitting light, the second substrate itself can be used as the other electrode by using the same material as the second substrate 3 described below. That is, when the second substrate 3 itself is a conductive substrate, titanium, tantalum, niobium, nickele, stainless steel, aluminum alloy, or the like is used. When the second conductive film 4 is made of titanium, tantalum, niobium, nickel, stainless steel, aluminum alloy, or the like, and the second substrate 3 is an insulating substrate, for example, blue plate glass, white glass, polyethylene terephthalate, polyethylene which is a transparent substrate. It is preferable to use glass ceramics, which are ceramics that are opaque substrates, such as naphthalate and polycarbonate, alumina, cement, clay, fluorine resin, or olefin resin, but is not limited to these materials.

  Moreover, as the semiconductor layer 5 which is an electron transporter made of a semiconductor to which a dye is adsorbed, a porous material such as titanium oxide, tin oxide, tungsten oxide, zinc oxide, tantalum oxide, niobium oxide, zirconium oxide or strontium titanate is used. Although it is suitable in that it has a large band gap, it is not limited to these materials.

  As the electrolyte layer 6, an iodine-based electrolytic solution made of iodine, potassium iodide, tetrapropylammonium iodine, dimethylpropylimidazolyl iodine, or the like is preferable in that the redox potential of the electrolyte iodine is more negative than the redox potential of the dye. However, it is not limited to these materials. For example, chloroplatinic acid, bromo or EMIBF4 / poly (2-hydroxyethyl methacrylate) or EMIFSI / polymethyl methacrylate gel-like electrolyte, polypyrrole, triphenyldiamine, Solid electrolytes such as CuDCN and CuI are also possible.

  In addition, the encapsulant 7 made of a coating type hot melt resin has a low gas diffusion coefficient because the polymer chains are dense and thermal vibration (hereinafter referred to as segment motion) is suppressed, or between the polymer chains. There is a strong interaction of hydrogen bonds, and segment motion is constrained.

  The hot melt resin may be, for example, an olefin resin, an ethylene copolymer resin, a polyester resin, a nylon resin, a vinyl acetate resin, a styrene / elastomer resin, a polyamide resin, or a urethane resin. However, the present invention is not limited to this, and any one of these materials or a mixture of two or more selected materials may be used. In addition, a functional separation type comprising an ethylene-vinyl alcohol copolymer resin, an ethylene-vinyl acetate copolymer resin, an ethylene-vinyl acetate-vinyl chloride copolymer resin, an ionomer resin, polyvinylidene chloride in contact with the outside world, or polypropylene. A multilayer structure may be used. The hot-melt resin that is the material of these sealing materials 7 has few volatile components and is in contact with a highly reactive electrolyte layer and components (such as oxygen gas and water vapor) containing external oxygen atoms, and therefore has a gas barrier property. Must be high and chemically stable. A hot melt resin, which is also a thermoplastic resin, has fewer reactive substituents than a thermosetting resin, and therefore can satisfy the above required characteristics such as high gas barrier property and chemical stability. In particular, if the hot melt resin is made of a polyvinyl alcohol resin, there is a strong hydrogen bond interaction between the polymer chains and the segment motion is constrained, so the polymer chain gap is dense and the segment motion is suppressed. Therefore, the gas diffusion coefficient is low, and the gas barrier property is the highest if there is no moisture. In addition, if it is made of polyvinylidene chloride resin, segment movement is suppressed because the polymer side chains are filled with relatively large atoms and molecules such as chlorine between the polymer chains, resulting in steric hindrance. In addition, it can be expected that the gas diffusion coefficient is low and the gas barrier property is high. Furthermore, if it is made of an ethylene-vinyl alcohol copolymer resin or an ethylene-vinyl acetate copolymer resin, the segment motion is restricted by the strong interaction of hydrogen bonds between the polymer chains. In other words, since the polymer chains are dense and the segment motion is suppressed, it is possible to expect actions and effects such as a low gas diffusion coefficient, a relatively strong moisture, and a high gas barrier property.

  2A to 2C, one electrode (first conductive film 2) formed on one main surface of the first substrate 1 and the other electrode (first electrode) formed on one main surface of the second substrate 3. 2 in the state where the two conductive films 4) are kept parallel to each other, the gap between the first base and the outer periphery of the electrolyte layer 6 and the gap between the outer periphery of the electrolyte layer 6 and the second base and the outer periphery of the electrolyte layer 6 are as follows. FIG. 2 is a plan view showing a state where the electrolyte layer 6 is applied with a sealing material 7 made of a hot melt resin that prevents permeation of oxygen and water.

  As shown in FIGS. 2A to 2C, the positional relationship between the first base (first substrate 1 and first conductive film 2) and the second base (second substrate 3 and second conductive film 4) is shown. It is possible to secure the gap between the two bases with the sealing material 7 by appropriately shifting. Further, by shifting the first substrate 1 and the second substrate 3 by an appropriate length in this way, as shown in FIG. 1, the one electrode (first conductive film 2) and the other electrode (second conductive film 4) This is preferable because a portion for taking out generated power can be easily secured.

  Here, as shown in FIG. 2A, when the first base and the second base (the first substrate 1 and the second substrate 3) have the same main surface (as shown, The first conductive film 2 and the second conductive film 4 can be formed to have the same width.) By using a substrate having the same width, the manufacturing is simple and the alignment is easy, and the transport apparatus is shared. This is advantageous in that it can.

  2B, one of the first substrate 1 and the second substrate 3 may have a large area (in the case of FIG. 2B, the first substrate 1 is wide. Thus, the first conductive film 2 is wider than the second conductive film 4). For example, as shown in FIG. 2 (b), by aligning the outer peripheral portion of the electrolyte layer 6 covered with the sealing material 7 with the width of the second substrate 3 as much as possible, it is possible to secure the region for photoelectric conversion as effectively as possible. This is preferable. In addition, since the coating surface is substantially flat, the coating operation is extremely easy.

  In addition, as shown in FIG. 2C, when the first substrate 1 and the second substrate 3 have the same size and are shifted in an oblique direction, the front and back coating surfaces are symmetrical, so that the thermal expansion occurs. This is preferable in that it can be made symmetrical, which is advantageous in terms of reliability, and is easy to apply because the application surface is almost flat.

  Next, the manufacturing method of the dye-sensitized solar cell of this invention is demonstrated. As shown in FIG. 3A, first, the first conductive film 2 made of the above-described material is formed on the first substrate 1 to a thickness of about 1 μm by, for example, a sputtering method or a CVD method. Further, the porous semiconductor layer 10 made of the above-described material is formed on the first conductive film 2 to a thickness of about 10 μm by, for example, a doctor blade method or a screen printing method.

  Next, the dye is carried as follows. First, when using, for example, a ruthenium complex as a dye, a solvent (for example, ethanol, acetonitrile, or dimethylformaldehyde) used for dissolving the dye is used. A first substrate made of the first substrate 1 and the first conductive film 2 on which the semiconductor layer 10 is formed is immersed in a solution in which the dye is dissolved, and the dye is supported on and adsorbed to the semiconductor layer for 1 to 24 hours. As shown in FIG. 3B, the semiconductor layer 5 carrying the dye on the first substrate was obtained.

  Next, as shown in FIG. 3C, a coating process of the electrolyte layer 6 is performed. That is, an appropriate amount of the electrolyte layer 6 is applied on the semiconductor layer 5 on the first substrate provided with the semiconductor layer 5 on which the dye is adsorbed by a casting method, a doctor blade method, a spray method, a screen printing method, or the like. Here, the liquid electrolyte layer 6 may be injected into the gap between the substrates by a dispenser or the like after the pasting step of both the substrates in FIG. Further, a certain gap between the first substrate 1 and the second substrate 3 may be formed by adding a bead-like, spherical, or cylindrical solid material made of ceramic, glass, plastic, or the like to the electrolytic solution.

  Next, as shown in FIG. 3 (d), when the second substrate made of the second substrate 3 and the second conductive film 4 is used as a counter electrode substrate in the substrate bonding step, the reduction catalyst for the electrolyte layer 6 is illustrated. A material in which platinum or carbon not shown is coated on the second conductive film 4 of the second substrate 3 as a counter electrode substrate by sputtering to a few nm is prepared. Then, the semiconductor layer 5 side of the first substrate 1 and the platinum side of the second substrate 3 in which platinum is covered with the second conductive film 4 are opposed to and closely adhered to each other. At this time, if bubbles are mixed in the electrolyte layer 6 between the two substrates, this step may be performed in a vacuum chamber or a vacuum chamber. Further, this step is performed in the glow box in order to suppress as much as possible the entry of external oxygen, moisture, and the like, which are degradation components of the dye and the electrolyte layer 6.

  Finally, as shown in FIGS. 3E and 3F, in the step of applying the sealing material 7, between the first base and the outer periphery of the electrolyte layer 6, the outer periphery of the electrolyte layer 6 and the second base. And the outer peripheral part of the electrolyte layer 6 are heated and coated with an olefin resin or the above-described ethylene copolymer resin as the sealing material 7 to seal the electrolyte layer 6. Here, the sealing material 7 may be applied up to the upper surface of the substrate or between the substrates so as not to block light. Further, this step may be performed in the glow box in order to suppress the contamination of the oxygen, moisture, and the like, which are deterioration components of the dye and the electrolyte layer 6, as much as possible.

  Next, as shown in FIG. 4, a dye-sensitized solar cell provided with an injection port 8 for injecting the electrolyte layer 6 can be obtained. Here, the injection port 8 was formed by a grinding method using a router such as an electrodeposited diamond bar, a carbide cutter, a carbon random grindstone, or a laser ablation method. In this way, a configuration using the second sealing material 9 made of a coating-type hot-melt resin is used for coating and sealing the interior between the substrates and the peripheral portion between the substrates and coating and sealing the inlet 8 of the electrolyte layer 6. Can be adopted. Further, since the injection port 8 has a smaller area than the outer periphery sealing portion of the electrolyte, the injection port 8 is sealed with a photo-curing resin or a thermosetting resin such as an epoxy resin having a gas barrier property lower than that of the olefin resin or the like. You can stop it.

  Hot melt resins are preferred because they have less or less reactivity than conventional epoxy resins and the like, and thus have a long pot life and can be stored in a cool and dark place, and are easy to handle. In addition, a hot melt resin such as an olefin resin has a high cohesive energy density, that is, a high gas barrier property, so that it is possible to suppress the volatilization of components of the electrolyte layer 6 and the intrusion of oxygen and moisture in the outside world. The weather resistance of the sensitive solar cell can be improved, and high productivity can be achieved by coating and sealing without heating the substrate.

  Next, a method for manufacturing the dye-sensitized solar cell shown in FIG. 4 will be described.

  5A to 5G are schematic process cross-sectional views schematically showing a typical method for manufacturing the photoelectric conversion device. First, in FIG. 5 (a), the porous semiconductor is baked in the same manner as in FIG. 3 (a), and in the same manner as in FIG. 3 (b), the dye carrying step shown in FIG. 5 (b). To do.

  Next, as shown in FIG. 5 (c), in pasting the substrates, the second substrate is used as a counter electrode substrate, and platinum not shown as a reduction catalyst for the electrolyte layer 6 is formed on the second conductive film 4 of the counter electrode substrate. A substrate coated with about several nm by sputtering is prepared. Here, the second substrate 3 is provided with one or more injection ports 8 for injecting the electrolyte layer 6 by a router (in this case, when the electrolyte layer is injected under vacuum, the injection port 8 In addition, for example, when two places are provided, one may be used as an injection place and the other may be used as an air vent.)

  On one substrate side, a bead-like, spherical, or cylindrical solid material made of ceramics, glass, plastic, etc., or a gap material 11 made of a thermoplastic resin or thermosetting resin mixed therewith, is installed to cure the substrates. A space for injecting a liquid to be the electrolyte layer 6 is formed on the substrate by pressure-bonding by the action of contraction. The gap material 11 is optimally light-cured or heat-cured with an epoxy resin mixed with hard plastic balls in terms of printability, low-temperature curability, strength, and chemical stability.

  Next, as shown in FIGS. 5D and 5E, in the coating step of the sealing material 7, a resin similar to that described in FIG. , Apply to form battery cells. Here, the first sealing material 7 may be applied to the upper surface of the substrate as long as it does not block light, that is, as shown in FIG.

  Next, as shown in FIG. 5 (f), in injecting the liquid to be the electrolyte layer 6, the liquid is injected from one injection port 8 and the air is extracted from the other injection port 8. The electrolyte layer 6 without bubbles is formed. As described with reference to FIG. 3, in order to suppress the mixing of oxygen and moisture, which are the causes of pigment deterioration, as much as possible, this step may be performed in a glow box in terms of improving durability. Furthermore, when the dye and the electrolyte layer 6 dislike oxygen and moisture from the outside, the liquid that becomes the battery cell and the electrolyte layer 6 is placed under reduced pressure, the inside of the battery cell is decompressed, and the inlet 8 is immersed in the liquid. When the liquid that becomes the battery cell and the electrolyte layer 6 is brought to normal pressure with an inert gas, the liquid is injected from the inlet 8, and the electrolyte layer 6 can be formed in the battery cell. Moreover, when injecting the liquid which becomes the electrolyte layer under reduced pressure, only one injection port may be provided.

  Finally, as shown in FIG. 5G, in the application of the sealing material 7, a resin such as an olefin-based resin is heated and applied as the second sealing material 9 to the injection port 8 to seal the electrolyte layer 6. . Note that this step may be performed in a glow box in order to suppress as much as possible the entry of external oxygen, moisture, and the like, which are degradation components of the dye and electrolyte layer. Further, since the injection port 8 has a smaller area than the outer periphery sealing portion of the electrolyte, the injection port 8 is sealed with a photo-curing resin or a thermosetting resin such as an epoxy resin having a gas barrier property lower than that of the olefin resin or the like. You can stop it.

  Another dye-sensitized solar cell of the present invention is shown in FIG. This dye-sensitized solar cell is obtained by heating and applying and laminating resins having different gas permeability as a sealing material for the electrolyte layer 6. In particular, an ethylene-vinyl acetate copolymer resin having a high oxygen barrier property is heated and applied as an encapsulant 7 at the opening of the gap between both substrates to seal the electrolyte layer 6, and the encapsulant 7 is further covered. By heating and applying a fluorine-based resin (PCTFE (polychlorotrifluoroethylene)) having a high water vapor barrier property as the sealing material 12, a multilayer sealing structure is formed. It is suitable in that it can suppress the intrusion of as much as possible. Thereby, the dye-sensitized solar cell excellent in durability can be provided.

  Thus, the gas barrier property can be further improved by forming a plurality of hot melt resins having different gas barrier properties into a multilayer structure. The above-described ethylene-vinyl acetate copolymer resin having a high gas barrier property of oxygen or solvent cannot be used alone because it has a low gas barrier property of water vapor. However, the life of a dye-sensitized solar cell can be achieved by forming a multilayer sealing structure with an organic film such as a fluorine-based resin having a high gas barrier property of water vapor and an inorganic film such as silicon nitride or aluminum at a portion in contact with the outside. Detachment of volatile components that are remarkably involved in oxygen and invasion of oxygen and water vapor can be suppressed simultaneously, and the reliability of the dye-sensitized solar cell can be improved.

  Still another dye-sensitized solar cell of the present invention is shown in FIG. As shown in FIG. 7, this dye-sensitized solar cell is characterized in that an olefin-based resin having a different gas permeability and a different material are laminated as a sealing material for the electrolyte layer 6. With this configuration, it is possible to provide an excellent dye-sensitized solar cell that can suppress as much as possible the entry of oxygen and moisture, which cause dye deterioration, into the electrolyte layer and can improve durability. In particular, an ethylene-vinyl acetate copolymer resin having a high oxygen barrier property is heated and applied as a sealing material 7 to the opening of the gap between the two substrates to seal the electrolyte layer 6. An adhesive layer (for example, ethylene-vinyl alcohol copolymer resin) 13 having a thickness of about 15 μm covering the entire surface side, and an inorganic film (for example, aluminum) 14 having a thickness of about 50 nm covering the surface of the adhesive layer 13 When a multilayer protective film made of a support film (for example, polyethylene terephthalate or polyvinylidene chloride) 15 having a thickness of about 23 μm covering the entire surface of 14 is laminated so as to cover the opening of the gap between the substrates, oxygen and moisture are further increased. This is preferable in that it can suppress the intrusion of.

  Thus, according to the dye-sensitized solar cell of the present invention, most of the electrolyte layer contains halogen such as iodine, but the sealing material made of hot melt resin is durable against this highly reactive electrolyte layer. Is expensive. Moreover, since there are few reactive substituents, gas barrier property is also high, volatilization of an electrolyte layer and its solvent can be suppressed, and the weather resistance of a dye-sensitized solar cell can be improved. In addition, since the gas barrier property is high, the ingress of moisture (moisture) and oxygen in the outside world can be suppressed, and the weather resistance of the dye-sensitized solar cell can be improved.

In addition, only hot-melt resin can be heated, hot-melt resin can be melted, applied to the sealing part, and the electrolyte layer can be sealed. Can be improved.

  Conventionally, when a reactive sealing material such as a thermosetting type such as an epoxy resin or a silicone resin hardens, it comes into contact with a highly reactive electrolyte layer, and the reaction product of the sealing material deteriorates and becomes durable. May decrease. Further, the reactive resin has many reactive substituents such as —OH group, —CO— group, —NH— group, —CN group, —OCO— group, —COOR— group even after the curing is completed. Therefore, it is easily eroded by the highly reactive electrolyte layer. On the other hand, the encapsulant made of the coating-type hot melt resin of the present invention seals the periphery of the substrate (step of adsorbing or binding the dye to the semiconductor layer before sealing) The part to be contacted is filled and sealed in a sealed part by a hot melt applicator heated by a heater or a hot melt gun. Therefore, since there is no need to heat the sealing portion, there is no deterioration of the dye or the electrolyte layer. Further, since heating of a large area substrate or the like is not required, manufacturing is simplified and productivity can be expected to be improved.

  In addition, when the inside of the substrate is sealed and adhered (step of sealing the substrate before the step of adsorbing or bonding the dye to the semiconductor layer), after applying a hot melt resin on the substrate by a hot melt applicator or printing, The opposite substrates are heated and pressure-bonded to seal and bond the substrates, and then the dye is injected from the injection port of the substrate, the dye is adsorbed to the semiconductor layer, the solvent is injected from the injection port, and the excess dye is injected. Wash. Then, after the semiconductor layer is dried, a liquid to be an electrolyte layer is further injected, and then the inlet is coated and sealed using a hot melt resin, so that the dye is not heated and the dye is deteriorated. There is no.

  The sealing material comprising the hot melt resin of the present invention includes an olefin resin, an ethylene copolymer resin, a polyester resin, a nylon resin, a vinyl acetate resin, a vinyl alcohol resin, an ionomer resin, a vinyl chloride resin, According to styrene / elastomeric resin, polyamide resin, urethane resin, or mixed system thereof or copolymer system thereof, gas barrier properties are high, so that the volatilization of components of the electrolyte layer and the external oxygen and water vapor, etc. Since the intrusion of moisture can be suppressed, the long-term reliability of the dye-sensitized solar cell can be improved. Moreover, since hot melt resin has few reactive substituents, the sealing property fall by the electrolyte layer with high reactivity does not occur.

  Resin film having an oxygen barrier property on the side where the encapsulating material comprising the coating type hot melt resin of the present invention contacts the electrolyte layer, such as ethylene-vinyl alcohol copolymer resin, ethylene-vinyl acetate copolymer resin, ethylene- Functional separation type comprising a vinyl acetate-vinyl chloride copolymer resin or ionomer, and a water vapor barrier resin such as polyvinylidene chloride, polypropylene or an inorganic membrane (for example, silica or aluminum) on the side in contact with the outside world With this multilayer structure, ethylene-vinyl alcohol has a high gas barrier property of the solvent, which is a volatile component of the electrolyte layer, with respect to an electrolyte layer that does not contain moisture but contains a solvent and an external environment that contains no solvent but contains moisture. Copolymer resin, ethylene-vinyl acetate copolymer resin, ethylene-vinyl acetate-vinyl chloride A resin such as a copper copolymer resin or an ionomer is provided on the electrolyte layer side, and polyvinylidene chloride or polypropylene having a high gas barrier property for moisture and oxygen in the outside world is provided on the outside side, and the substrates are sealed by sealing the substrates. There is no need to heat the substrate at the time of stopping, and the dye is not further deteriorated. Thereby, the long-term reliability of the dye-sensitized solar cell can be improved.

  By sealing the coating type hot melt resin sealing material of the present invention with a film having a water vapor barrier property, for example, a laminated film made of an ethylene-vinyl acetate copolymer resin and a metal film such as an aluminum alloy. The volatile components of the electrolyte layer can be suppressed, and the long-term reliability of the dye-sensitized solar cell can be improved.

  By mixing a gap material (maximum particle size of 10 μm or more and 500 μm or less) into the sealing material made of the coating type hot melt resin of the present invention, variation in sealing and sealing gaps between substrates can be suppressed, Variations in the conversion efficiency of the dye-sensitized solar cell can be suppressed. Here, since the thickness of the semiconductor layer is 10 μm, the gap between the substrates needs to be 10 μm or more. On the other hand, when the gap is 500 μm or more, the thickness of the electrolyte layer is 500 μm or more, and the distance that the charge of the electrolyte layer moves increases, resulting in a decrease in conversion efficiency.

  By mixing a light absorber into the sealing material made of the hot melt resin of the present invention, the sealing material can be locally heated by light, the thermal expansion of the substrate can be suppressed, and the sealing reliability is improved. can do.

  In addition, the photoelectric conversion apparatus of this invention is not limited to the dye-sensitized solar cell mentioned above, What is necessary is just to have a photoelectric conversion function, and it can apply also to various light receiving elements, an optical sensor, etc.

  The photoelectric conversion device described above can be used as a power generation unit, and a photovoltaic power generation device configured to supply the generated power from the power generation unit to a load can be obtained.

  That is, when one or more of the above-described photoelectric conversion devices (if there are a plurality of photoelectric conversion devices connected in series, parallel, or series-parallel) are used as power generation means for power supply, The generated power may be directly supplied to the DC load.

  In addition, after converting the above-described photovoltaic power generation means to appropriate AC power via power conversion means such as an inverter, this generated power is supplied to an AC load such as a commercial power supply system or various electric devices. It is good also as a power generator which can be.

  Furthermore, such a power generation apparatus can be used as a photovoltaic power generation apparatus such as a solar power generation system of various aspects by installing it in a building with a good sunlight.

  Thus, a highly efficient and durable photovoltaic device can be provided.

  In the following, specific examples of the dye-sensitized solar cell of the present invention will be described.

<Example 1>
Examples of the dye-sensitized solar cell shown in FIG. 1 will be described. As shown in FIG. 3A, first, a transparent glass substrate is used as the first substrate 1, and a transparent first conductive film 2 made of fluorine-doped tin oxide (SnO ₂ ) is formed on one main surface. A first transparent conductive substrate of 1.1 mm thickness (conductive glass plate “A110U80” manufactured by Asahi Glass Co., Ltd. (a glass plate coated with fluorine-doped tin oxide (SnO ₂ ) on a glass plate)) was prepared. . Similarly, the second substrate 3 is a transparent second conductive film made of a second substrate 3 disposed to face one main surface of the first base and fluorine-doped tin oxide (SnO ₂ ) on the one main surface. A second transparent conductive substrate (the same material and the same thickness as the first substrate) of the second substrate composed of the film 4 was prepared.

  Next, in firing the porous semiconductor layer 10, the semiconductor layer 10 having a thickness of 10 μm was formed on the first conductive film 2. That is, an anatase powder of titanium oxide having an average particle size of about 20 nm was moistened with acetylacetone to increase the surface potential of titanium oxide and reduce the cohesiveness.

  Thereafter, a titanium oxide paste was prepared by kneading titanium oxide with deionized water and stabilizing with a surfactant (polyoxyethylene (10) octylphenyl ether). Then, this paste was applied to the thickness of 25 μm on the surface of the first conductive film 2 by a doctor blade method. And the porous semiconductor layer 10 was formed by baking at about 450 degreeC for 30 minutes in air | atmosphere.

  Next, as shown in FIG. 3B, the dye was carried. As this dye, a ruthenium complex was used, and acetonitrile and t-butanol (1: 1 by volume) were used as solvents used for dissolving the dye. A first substrate serving as a support substrate composed of the first substrate 1 and the first conductive film 2 on which the semiconductor layer 10 shown in FIG. 3A is formed is immersed in a solution in which the dye is dissolved, and the dye is added to the semiconductor layer. A semiconductor layer 5 having a thickness of 10 μm and supporting a dye was obtained by supporting and adsorbing on 10 for 12 hours.

  Next, as shown in FIG. 3C, the electrolyte layer 6 was applied and formed. An iodine-based electrolyte layer 6 (iodine, lithium iodide (inorganic iodide salt), dimethylpropylimidazolium iodine (imidazolium) is formed on the semiconductor layer 5 on the first substrate provided with the semiconductor layer 5 on which the dye is adsorbed. Iodide salt), tertiary butyl pyridine (additive), and methoxyacetonitrile (solvent)) were applied in an appropriate amount to a thickness of 25 μm by a casting method.

  Here, after the two substrates (the first substrate 1 and the second substrate 3) are pasted together, the electrolyte layer 6 may be injected into the gap between the two substrates by a dispenser or the like.

  Next, in the pasting of the substrates shown in FIG. 3D, when a second transparent conductive substrate that is a counter electrode substrate composed of the second substrate 3 and the second conductive film 4 is used, as a reduction catalyst for the electrolyte layer 6. A material in which platinum or carbon (not shown) was coated on the second conductive film 4 of the second substrate by sputtering to about 65 nm was prepared. Then, the semiconductor layer 5 side of the first substrate and the platinum layer side of the second substrate obtained by coating the platinum layer with the second conductive film 4 were opposed to each other and adhered. At this time, when air bubbles were mixed between the substrates and in the electrolyte layer 6, this step was performed in a vacuum chamber or a vacuum chamber. Further, this step was performed in a glow box in order to suppress the entry of external oxygen, moisture, etc., which are deterioration components of the dye and electrolyte layer 6.

  Finally, as shown in FIGS. 3 (e) and 3 (f), in the application of the sealing material 7, an olefin resin is heated and applied as the sealing material 7 to the opening of the gap between the two substrates, and the electrolyte layer 6 The outer periphery of was sealed. Here, it is preferable that the sealing material 7 is applied to the upper surfaces of the two bases or between the bases so as not to block light, and is soaked in the gaps between the bases. Furthermore, this step may be performed in a glow box in order to suppress the entry of external oxygen, moisture, etc., which are deterioration components of the dye and electrolyte layer 6.

  According to this dye-sensitized solar cell, leakage of the electrolyte layer 6 and the like were not visually observed even after 6 months from the production, and it was completely sealed.

<Example 2>
Next, an example of the dye-sensitized solar cell of FIG. 4 will be described. In the same manner as in Example 1, the porous semiconductor was baked as shown in FIG. 5 (a), and the dye was carried as shown in FIG. 5 (b).

  Next, as shown in FIG. 5 (c), in pasting the substrates together, the second substrate composed of the second substrate 3 and the second conductive film 4 described in Example 1 is used as the counter electrode substrate, and the electrolyte layer 6 is formed. A substrate was prepared by coating platinum (not shown) as a reduction catalyst onto the second conductive film 4 of the counter electrode substrate to a thickness of about 65 nm by sputtering. Here, the second substrate 3 is provided with one or more injection ports 8 for injecting a liquid to be the electrolyte layer 6 by a router. In addition, a gap material 11 obtained by photocuring or thermosetting an epoxy resin mixed with a hard plastic ball having a diameter of 25 μm is installed on one of the substrates, the substrates are pressure-bonded by the effect of curing shrinkage, and a liquid is injected into the substrate. A space was formed.

  Next, as shown in FIGS. 5D and 5E, in the step of applying the sealing material 7, an olefin-based resin is heated and applied as a sealing material 7 to the peripheral edge of the gap between the two substrates to form a battery cell. Formed. Here, the first sealing material 7 may be applied up to the upper surface of the substrate as long as it does not block light, that is, as shown in FIG.

  Next, as shown in FIG. 5 (f), in injecting the liquid to be the electrolyte layer 6, the liquid is injected from one injection port 8 and the air is extracted from the other injection port 8. The electrolyte layer 6 could be formed without generating bubbles. Here, this step was performed in a glow box in order to suppress as much as possible the mixing of oxygen and moisture, which are the causes of pigment deterioration.

  Finally, in the application of the sealing material 7 in FIG. 5G, an olefin resin was heated and applied as the second sealing material 9 to the injection port 8 to seal the electrolyte layer 6. This process was also performed in the glow box.

  This dye-sensitized solar cell was also completely sealed without any leakage of the electrolyte layer 6 even after 6 months from the production.

<Example 3>
Next, examples of the dye-sensitized solar cell of FIG. 6 will be described. First, as in Example 1, a first substrate was prepared. Then, titanium oxide was used as the semiconductor layer 10. After adding acetylacetone to an anatase powder of titanium oxide having a particle size of about 20 nm, a paste of titanium oxide stabilized with a surfactant was prepared by kneading with deionized water. On the surface on which the first conductive film 2 is formed, the above paste is applied by a casting method and baked at 450 ° C. for 30 minutes in the air, thereby forming a porous semiconductor layer 10 similar to that in Example 1. .

  Next, a ruthenium complex was used as a dye in carrying the dye. Moreover, acetonitrile and t-butanol (1: 1 by volume) were used as the solvent used for dissolving the dye. Example 1 in which the support substrate, which is the first substrate on which the semiconductor layer 10 was formed, was immersed in a solution in which the dye was dissolved, and the dye was supported and adsorbed on the semiconductor layer 10 for 1 to 24 hours. A similar semiconductor layer 5 was obtained.

  Next, the second substrate was prepared as the same material as the first substrate. Then, platinum or carbon (not shown) as a reduction catalyst for the electrolyte layer 6 was coated on the second conductive film 4 of the second base as a counter electrode substrate by sputtering to a thickness of about 65 nm. The semiconductor layer 5 side of the first substrate and the platinum side of the second substrate in which platinum was covered with the second conductive film 4 were opposed to each other. This process was performed in a glow box to suppress the entry of external oxygen and moisture, which are degradation components of the dye and electrolyte layer.

  Next, after pasting the two substrates (the first substrate 1 and the second substrate 3), the iodine-based electrolyte layer 6 was injected into the gap between the two substrates using a dispenser or the like.

  Next, an electrolyte layer 6 was sealed by heating and applying an ethylene-vinyl acetate copolymer resin as the sealing material 7 to the opening of the gap between the two substrates. Furthermore, a multi-layer sealing structure was formed using fluororesin (PCTFE (polychlorotrifluoroethylene) as the sealing material 12. In order to suppress the entry of external oxygen, moisture, etc., which are degradation components of the dye and electrolyte layer, This step was performed in the box.

  This dye-sensitized solar cell was completely sealed without any leakage of the electrolyte layer 6 even after 6 months from the production.

<Example 4>
Next, an example of the dye-sensitized solar cell in FIG. 7 will be described.

  Since this dye-sensitized solar cell is the same as that of Example 1 until the production of the battery cell, description thereof is omitted.

  This dye-sensitized solar cell is characterized in that, as a sealing material for the electrolyte layer 6, olefin resins and different materials having different gas permeability are laminated in multiple layers. As a result, both oxygen and moisture that cause pigment deterioration can be prevented from entering the electrolyte layer 6 as much as possible, and durability can be improved. In particular, the electrolyte layer 6 is sealed by heating and applying an ethylene-vinyl acetate copolymer resin having a high oxygen barrier property as a sealing material 7 to the opening of the gap between the two substrates. Furthermore, a 15 μm thick Kuraray Eval-F ethylene-vinyl alcohol copolymer resin is laminated as an adhesive layer 13 covering the entire main surface of the first substrate, and the surface of the adhesive layer 13 is inorganic. The film 14 is coated with aluminum, and the entire surface of the inorganic film 14 is formed of polyethylene terephthalate as the support film 15. Thus, a multilayer protective film Toyobo Ester film E7078 is formed in multiple layers, thereby opening the gaps in the substrate. Covering the portion is preferable in that the intrusion of oxygen and moisture can be further suppressed. The formation of these multilayer protective films was performed in the glow box.

  Even in this dye-sensitized solar cell, leakage of the electrolyte layer 6 was not observed at all even after 6 months from fabrication, and it was completely sealed.

It is sectional drawing which shows typically an example of the photoelectric conversion apparatus of this invention. (A)-(c) is a top view which shows typically an example in the planar view of the photoelectric conversion apparatus of this invention, respectively. (A)-(f) is sectional drawing which shows typically an example of the manufacturing process of the photoelectric conversion apparatus of this invention, respectively. It is sectional drawing which shows typically an example of the other photoelectric conversion apparatus of this invention. (A)-(g) is sectional drawing which shows typically an example of the manufacturing process of the other photoelectric conversion apparatus of this invention, respectively. It is sectional drawing which shows typically an example of the other photoelectric conversion apparatus of this invention. It is sectional drawing which shows typically an example of the other photoelectric conversion apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 1st board | substrate 2 ... 1st electrically conductive film (one electrode)
3 ... 2nd substrate 4 ... 2nd electrically conductive film (other electrode)
5 ... Semiconductor layer carrying a dye (electron transporter)
6 ... electrolyte layer 7 ... sealing material 8 ... inlet 9 ... second sealing material
10 ... Semiconductor layer
11 ... Gap material
12 ... Third sealing material
13 ... Adhesive layer
14 ... Inorganic membrane
15 ... Support membrane

Claims (2)

A first substrate whose one principal surface is one electrode and a second substrate whose one principal surface is the other electrode are disposed with the one electrode and the other electrode facing each other, and the first substrate and the second electrode it with intervening electrolytic electrolyte layer between the substrate, the a photovoltaic device electron transporter having a dye that performs photoelectric conversion is provided on the other hand on an electrode, wherein the first substrate and the second substrate The hot melt resin covers the outer periphery of the electrolyte layer from the side surface of one of the substrates and extends over the one main surface of the other substrate , and the thickness in the direction parallel to the side surface is from the one substrate. A photoelectric conversion device, wherein the photoelectric conversion device is applied so as to become smaller as it leaves. A photovoltaic device comprising the photoelectric conversion device according to claim 1 as a power generation means, and the power generated by the power generation means is supplied to a load.

Images