JP4467879B2 - Manufacturing method of dye-sensitized solar cell - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a dye-sensitized solar cell , and more particularly to a method of bonding and sealing two substrates constituting the dye-sensitized solar cell with high durability.
[0002]
[Prior art]
Dye-sensitized solar cells were developed by Grezel in Switzerland and have the advantages of high photoelectric conversion efficiency, low manufacturing costs, and environmental friendliness. Reference 1).
[0003]
FIG. 3 shows an example of this dye-sensitized solar cell. Reference numeral 1 in the drawing denotes a first substrate that forms a working electrode. The first substrate 1 is made of a sheet made of a transparent resin such as a glass plate, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, or polyethersulfone.
[0004]
A transparent conductive film 2 such as tin-doped indium oxide (ITO) or fluorine-doped tin oxide (FTO) is formed on the first substrate 1. A grid-like metal wiring layer 3 for collecting current is formed on the transparent conductive film 2 so as not to impair the light transmittance.
[0005]
An oxide semiconductor porous film 4 made of a metal oxide semiconductor such as titanium oxide, tin oxide, tungsten oxide, zinc oxide, or neodymium oxide is formed on the metal wiring layer 3. A photosensitizing dye such as bipyridine or terpyridine is supported, and a transparent conductive film 2, a metal wiring layer 3, an oxide semiconductor porous film 4, and a photosensitizing dye are provided on the first substrate 1. And constitutes a working electrode.
[0006]
Moreover, the code | symbol 5 in a figure shows the 2nd board | substrate which makes a counter electrode. The second substrate 5 is made of a glass plate, a resin sheet, a metal sheet or the like, and is made of an insulating material such as a glass plate or a resin sheet. On the second substrate 5, a metal thin film such as platinum, FTO, ITO or the like is formed. The conductive film 6 is used, which is used alone or in combination.
[0007]
Further, an electrolytic solution 7 is filled in a gap between the first substrate 1 constituting the working electrode and the second substrate 5 constituting the counter electrode. The electrolytic solution 7 includes an ionic liquid such as a volatile solvent such as acetonitrile, propionitrile, or propylene carbonate as a solvent, or a salt formed of 1-ethyl-3-methylimidazolium cation and bis (trifluoromethylsulfonyl) imide anion. For example, a solution obtained by dissolving iodine ions / iodine, bromine ions / bromine, etc. as a redox pair, or a solid electrolyte solution obtained by gelling these electrolyte solutions is used. Further, in place of the electrolytic solution 7, a p-type semiconductor such as copper iodide or copper thiocyanide can be used as the charge transfer layer.
[0008]
Moreover, the 1st board | substrate 1 and the 2nd board | substrate 5 are joined and sealed by the sealing material 8 which consists of resin, such as an epoxy resin, an ultraviolet curable resin, and an olefin resin, in the peripheral part. It is configured to prevent leakage of the electrolyte 7 inside the cell to the outside and entry of foreign matter and moisture from the outside into the cell.
[0009]
The dye-sensitized solar cell having such a structure is mainly used outdoors. In that case, the surface temperature is exposed to a high temperature exceeding 80 ° C. Moreover, it will also be exposed to wind and rain for a long time. Under such conditions of use, the substrates 1 and 5 are sealed with the sealing material 8 made of resin, so that concerns such as durability and safety remain.
[0010]
In order to solve such problems, there has been proposed a method for joining and sealing the substrates by using an inorganic material glass frit for the substrate constituting the dye-sensitized solar cell and melting the substrate (patent) Reference 2).
However, since this method melts the glass frit, it is necessary to heat the entire cell to about 400 ° C. When the substrate is exposed to such a high temperature, the photosensitizing dye supported on the oxide semiconductor porous film is thermally deteriorated. For this reason, in this method, a small hole is formed when the substrate is sealed, and the dye solution is introduced and circulated inside the cell using this small hole, which complicates the manufacturing process. Therefore, there is a disadvantage that the cost increases.
[0011]
[Patent Document 1]
Japanese Patent No. 2664194 [Patent Document 2]
JP 2001-185244 A
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to perform sealing excellent in durability, safety, and the like by a simple operation when bonding and sealing a substrate constituting a dye-sensitized solar cell. .
[0013]
[Means for Solving the Problems]
To solve this problem,
The invention according to claim 1 is the first substrate on which the transparent conductive film and the oxide semiconductor porous film are formed, and the oxide semiconductor porous film carries a photosensitizing dye as a working electrode,
Then, when this first substrate and the second substrate as a counter electrode are overlapped and sealed at the peripheral edge,
A glass frit layer is disposed on the peripheral edge of one or both substrates, and the first and second glass frit layers are melted by irradiating the glass frit layer through one of the substrates and melting the glass frit layer. A method for producing a dye-sensitized solar cell , comprising bonding and sealing a substrate.
[0014]
The invention according to claim 2 is a method for producing a dye-sensitized solar cell according to claim 1, wherein a glass frit layer is formed by applying a paste containing glass frit.
The invention according to claim 3 is the dye-sensitized solar according to claim 1 or 2, wherein the wavelength of the laser light is in a wavelength region such that the transmittance of any of the substrates is 50% or more. It is a manufacturing method of a battery .
[0016]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below.
1 and 2 schematically show an example of the dye-sensitized solar cell of the present invention . 1 and 2, reference numeral 1 denotes a first substrate, and reference numeral 5 denotes a second substrate.
[0017]
In FIGS. 1 and 2, the transparent conductive film 2, the metal wiring layer 3, the photosensitizing dye-carrying oxide semiconductor porous film 4 on the first substrate 1, and the second are shown in FIG. The conductive film 6 on the substrate 5 is not shown, and these components are the same as those shown in FIG. 3 described above including the first substrate 1 and the second substrate 5. The description is omitted.
[0018]
The first substrate 1 and the second substrate 5 are overlaid at a predetermined interval, and a glass frit layer 11 is disposed on the peripheral edge of the substrate. As shown in FIG. 2, the glass frit layer 11 is arranged in a strip shape on the peripheral edge of one or both of the substrates 1 and 5. The glass frit layer 11 is formed by applying a paste containing glass frit to a substrate by an application means such as printing, heating, drying, or pre-baking.
[0019]
The glass frit used here is a mixture of one or more glasses of lead oxide, boron oxide, sodium oxide, barium oxide, silicon oxide, aluminum oxide, iron oxide, calcium oxide, magnesium oxide, titanium oxide, etc. Then, after cooling, a pulverized powder having a particle size of 0.1 to 10 μm is used. The glass frit is preferably a low-melting type whose melting temperature is 600 ° C. or lower.
[0020]
The powdery glass frit is kneaded by adding a resin component such as an acrylic resin serving as a binder and a solvent to be added as necessary to obtain the paste. Further, particles having a large particle diameter made of an inorganic material having a high melting point may be mixed in the paste so that the glass frit layer 11 functions as a spacer for keeping the substrates 1 and 5 at a predetermined interval. .
[0021]
The width and thickness of the glass frit layer 11 are not particularly limited and are appropriately selected depending on the dimensions of the substrate, the use environment, etc. The width is a minimum of 0.5 mm, and the thickness is the same as that of the dye-carrying oxide semiconductor porous film 4. It is determined to be at least the same height. Further, the formation position on the substrate is not particularly limited, and may be determined as appropriate according to the specifications.
[0022]
Next, the first and second substrates 1 and 5 that are overlapped with the glass frit layer 11 are irradiated with laser light 12 through the substrate 1 (5) and targeting the glass frit layer 11. Is done.
[0023]
As the laser beam 12 used here, a laser beam having a wavelength in a wavelength region in which the transmittance of one of the substrates 1 (5) is 50% or more is used. Specifically, a gallium arsenide semiconductor is used. Laser light from a laser, a gallium arsenide aluminum semiconductor laser, a YAG laser, or the like is used. If the transmittance at the substrate is less than 50%, the laser beam reaching the glass frit layer 11 decreases, and conversely, the substrate 1 (5) is heated and becomes inconvenient.
[0024]
The intensity of the laser beam only needs to be sufficient to melt the glass frit layer 11, and the size of the laser beam irradiation spot, the moving speed thereof, and the like may be appropriately determined. The laser beam irradiation trajectory is not particularly limited as long as the glass frit layer 11 is sufficiently heated. For example, a wobbling method or a painting method is preferable.
[0025]
In the wobbling method, the center of the irradiation spot of the laser beam is swung and the glass frit layer 11 is advanced along the longitudinal direction. In the painting method, the irradiation target region is filled with a trajectory that draws a large number of parallel lines.
The laser beam irradiation as described above can be performed using a commercially available scanning laser marker device or the like.
[0026]
The glass frit layer 11 is heated by irradiation of the laser beam 12 through one of the substrates 1 (5), and the glass frit layer 11 is melted by the heat. The substrates 1 and 5 are bonded and sealed.
[0027]
Next, a dye-sensitized solar cell is completed by filling and sealing the electrolyte between the two substrates 1 and 5. The electrolytic solution is filled by a method in which the glass frit layer 11 is previously passed through a thin pipe, the glass frit layer 11 is melted, two substrates are joined, and then the electrolytic solution is injected through the pipe. For example, a method of injecting through a small hole formed in advance in the second substrate 5 is performed. If the electrolytic solution has a high viscosity, the inside of the cell can be evacuated and injected into the cell using the pressure difference formed thereby.
[0028]
According to such a manufacturing method, since the sealing portion between the substrates 1 and 5 is composed of the glass frit of an inorganic material, the sealing portion is firmly bonded, and chemically, mechanically, and thermally. It has high characteristics and exhibits excellent durability and safety. Even if this dye-sensitized solar cell is used outdoors under severe conditions for a long time, the electrolyte leaks from the sealed part. And no intrusion of moisture or foreign matter.
[0029]
Further, since the laser beam 12 is irradiated only on the peripheral portions of the substrates 1 and 5, the photosensitizing dye carried on the oxide semiconductor porous film 4 formed on the first substrate 1 is heated. The first substrate 1 carrying the dye can be bonded and sealed without being deteriorated, and the manufacturing operation becomes simple.
[0030]
In the manufacturing method of this invention, the above-mentioned sealing method and various sealing methods, such as the sealing method using the conventional resin, can be used together.
[0031]
Specific examples are shown below.
(Example 1)
A glass frit layer was formed on the peripheral edge of a commercially available soda glass plate. This glass frit layer has a width of 4 mm and a thickness obtained by printing a glass frit having a melting temperature of 500 ° C. and a particle diameter of 5 μm or less, an acrylic resin and α-terpineol, and heating and baking at 300 ° C. 20 μm.
[0032]
Next, two glass plates were overlapped, and the laser beam was irradiated through one glass plate. As the laser light, laser light having a wavelength of 840 nm from a gallium arsenide semiconductor laser was used and irradiated while scanning.
Thereby, the two glass plates were firmly joined.
[0033]
This bonded glass plate was irradiated with ultraviolet rays for 300 hours continuously by an ultraviolet tester. A peeling test of the bonded surface of the glass plate after irradiation was conducted, but no significant decrease in adhesive strength was observed.
For comparison, a glass plate bonded and sealed using an olefin resin (“HIMILAN” manufactured by Mitsui Chemicals, Inc.) as a bonding material has a marked decrease in adhesive strength after ultraviolet irradiation.
[0034]
(Example 2)
On a glass plate having a transparent conductive film made of fluorine-added tin oxide, a titanium oxide dispersion having an average particle size of 25 nm was applied, dried, and heated and sintered at 450 ° C. for 1 hour. This was immersed in an ethanol solution of a ruthenium bipyridine complex (N3 dye) for 8 hours to carry the dye, thereby obtaining a working electrode.
[0035]
In addition, a platinum thin film was formed by sputtering on a glass plate having a transparent conductive film made of fluorine-added tin oxide, and used as a counter electrode.
These glass plates were bonded to face each other. The bonding here was performed in the same manner as in the laser irradiation method using the glass frit shown in Example 1.
As the electrolyte, a methoxyacetonitrile solution in which 0.5 mol / liter iodide salt and 0.05 mol / liter iodine are dissolved is injected into the gap between the glass plates through an injection hole formed in the counter electrode in advance. Thus, a test cell having a size of 10 mm × 10 mm was produced.
[0036]
The test cell was subjected to a continuous light irradiation test (300 hours) and a high temperature holding test (300 hours) using a sunshine weatherometer. When the change of the photoelectric conversion efficiency of the test cell before and after the continuous light irradiation test and the high temperature holding test was observed, the value of 80% or more of the initial value was held.
[0037]
For comparison, a similar test was performed on a comparative cell that had a similar structure and was bonded and sealed using an olefin resin ("Hi-Milan" manufactured by Mitsui Chemicals Co., Ltd.). However, the photoelectric conversion efficiency has decreased to a value of 50% or less of the initial value. When this comparative cell was observed after the test, it was confirmed that many bubbles were present inside. It is considered that this is because the sealing material is deteriorated and the electrolytic solution is volatilized, so that the cell characteristics are greatly deteriorated.
[0038]
【The invention's effect】
As described above, according to the present invention, since bonding and sealing between substrates are performed by glass frit of an inorganic material, it is possible to manufacture a dye-sensitized solar cell having high durability and safety over a long period of time. it can.
[0039]
In addition, since the glass frit is melted and bonded by irradiating laser light, the oxide semiconductor porous film formed on the substrate is not heated, so that the photosensitizing dye is supported on the oxide semiconductor porous film. Since the processed substrate can be targeted, the manufacturing operation is not troublesome.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an example of a production method of the present invention.
FIG. 2 is a schematic configuration diagram showing an example of the production method of the present invention.
FIG. 3 is a schematic cross-sectional view showing a dye-sensitized solar cell as a photoelectric conversion element in the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... 1st board | substrate, 5 ... 2nd board | substrate, 11 ... Glass frit layer, 12 ... Laser beam.

Claims (3)

For the first substrate on which the transparent conductive film and the oxide semiconductor porous film are formed, a photosensitizing dye is supported on the oxide semiconductor porous film as a working electrode,
Then, when this first substrate and the second substrate as a counter electrode are overlapped and sealed at the peripheral edge,
A glass frit layer is disposed on the peripheral edge of one or both substrates, and the first and second glass frit layers are melted by irradiating the glass frit layer through one of the substrates and melting the glass frit layer. A method for producing a dye-sensitized solar cell, comprising bonding and sealing a substrate. The method for producing a dye-sensitized solar cell according to claim 1, wherein a glass frit layer is formed by applying a paste containing glass frit. The method for producing a dye-sensitized solar cell according to claim 1 or 2, wherein the wavelength of the laser light is in a wavelength region such that the transmittance of any of the substrates is 50% or more.

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