JP2005228614A - Counter electrode for dye-sensitized solar cell, and dye-sensitized solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate manufacture of a dye-sensitized solar cell having a plurality of cells (unit cell) connected in series, and to reduce its manufacturing cost. <P>SOLUTION: On a film substrate 1, as a transparent electrode 2, a transparent electrode 2a of the size of two cells and a transparent electrode 2b of the size of one cell are installed. On this transparent electrode 2a, a dye-sensitized semiconductor (titania electrode) 3a of the share of one cell size and the counter electrode 6a of the share of one cell size having light transmittance are installed. On the film substrate 7, the counter electrode 6a of the share of one cell size, and the electrode 10 of the share of two cell sizes are installed. As for the electrode 10, a thin film of platinum is preferable, but not limited to this. The counter electrode 6a is arranged opposed to the semiconductor electrode 3a. On the electrode 10, the semiconductor electrode 3A of the share of one cell size and the counter electrode 6b of the share of one cell size are installed, and this semiconductor electrode 3A is opposedly installed to the counter electrode 6a, and the counter electrode 6b is opposedly installed to the semiconductor electrode 3b. Output voltage is taken out from the middle of the semiconductor electrode 2b and the counter electrode 6a. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a dye-sensitized solar cell, and more particularly to a dye-sensitized solar cell in which an output voltage is increased by connecting a plurality of unit cells in series.

  It is already known that a solar cell is configured using an oxide semiconductor adsorbed with a sensitizing dye as an electrode. FIG. 3 is a sectional view showing a general structure of such a dye-sensitized solar cell. A transparent electrode 2 is provided on the film substrate 1, and a semiconductor electrode 3 on which a spectral sensitizing dye is adsorbed is formed on the transparent electrode 2. A counter electrode 6 is disposed opposite to the semiconductor electrode 3, and an electrolyte solution 5 is sealed between the dye-sensitized semiconductor electrode 3 and the counter electrode 6. The counter electrode 6 is formed on a film substrate 7.

  The dye-adsorbing semiconductor film 3 is usually composed of a titanium oxide thin film on which a dye is adsorbed. The dye adsorbed on the titanium oxide thin film is excited by visible light, and power is generated by passing the generated electrons to the titanium oxide fine particles. In the counter electrode 6, a transparent conductive film such as ITO (indium tin oxide) or FTO (fluorine-doped tin oxide) is formed on a substrate 7, and on the transparent conductive film, between the transparent conductive film and the sensitizing dye. A platinum film or a carbon film as a catalyst for promoting the transfer of electrons is formed to a thickness that does not decrease the transmittance.

As the electrolyte in the electrolyte solution 5, the redox substance, for example, LiI, NaI, KI, combinations of metal iodides and iodine, such as CaI _2, LiBr, NaBr, KBr, the metal bromide and bromine, such as CaBr ₂ combination, Preferably, an electrolytic solution is used in which a redox material comprising a combination of metal iodide and iodine is dissolved in a solvent such as a carbonate compound such as propylene carbonate or a nitrile compound such as acetonitrile.

  When assembling such a dye-sensitized solar cell, the substrate 1 provided with the transparent electrode 2 and the semiconductor electrode 3 and the substrate 7 provided with the counter electrode 6 are arranged with the liquid sealing material 4 at the periphery. The electrolyte solution 5 is injected into the gap between the semiconductor electrode 3 and the counter electrode 6 and sealed.

  Dye-sensitized solar cells have a maximum open circuit voltage of about 0.7 V in a single cell, so it is necessary to produce a module in which a plurality of cells (unit cells) are connected in series in actual use. was there.

  FIG. 2 is a schematic cross-sectional view of a conventional dye-sensitized solar cell having such a series connection structure of unit cells. In this dye-sensitized solar cell, the transparent electrode 2 and the top thereof are formed so that a plurality (three in the drawing) of unit cells (first cell, second cell, and third cell) are formed. The semiconductor electrode 3 and the counter electrode 6 are each divided into three pieces. The transparent electrode 2 of the first cell and the counter electrode 6 of the second cell are electrically connected by the conductor 8, and the transparent electrode 2 of the second cell and the counter electrode 6 of the third cell are electrically connected by the conductor 8. Thereby, the first, second and third cells are connected in series, and an output voltage is obtained between the counter electrode 6 of the first cell and the transparent electrode 2 of the third cell.

  In the conventional dye-sensitized solar cell shown in FIG. 2, the semiconductor electrode 3 is necessarily disposed on the upper substrate 1 on which sunlight is incident, while the counter electrode 6 is necessarily disposed on the lower substrate 7. . Therefore, in order to connect adjacent cells in series, it is necessary to establish conduction between the transparent electrode 2 on the upper substrate and the counter electrode 6 on the lower substrate 7 by the conductor 8, and for this reason, a module is manufactured. The process was complicated and expensive.

  An object of the present invention is to facilitate manufacture of a dye-sensitized solar cell having a plurality of cells (unit cells) connected in series, and to reduce manufacturing costs.

  The dye-sensitized solar cell of the present invention (invention 1) includes a dye-sensitized semiconductor electrode, a counter electrode provided facing the dye-sensitized semiconductor electrode, and the dye-sensitized semiconductor electrode. A dye-sensitized solar cell having an electrolyte solution disposed between the counter electrode and the dye-sensitized semiconductor electrode and the counter electrode provided on the substrate. A sensitized semiconductor electrode and a counter electrode are disposed, a counter electrode facing the dye-sensitized semiconductor electrode on the first substrate, and a counter electrode on the first substrate on the second substrate. A plurality of unit cells are formed by disposing the opposed dye-sensitized semiconductor electrodes, and the dye-sensitized semiconductor electrodes provided on the first substrate and the second substrate are provided. Opposite provided on the first substrate adjacent to the unit cell comprising the counter electrode There is disposed a unit cell consisting of poles and a dye-sensitized semiconductor electrode provided on a second substrate, in which the unit cell is characterized in that it is connected in series.

  The dye-sensitized solar cell according to claim 2 is characterized in that, in claim 1, partition means for separating the electrolyte solution of each unit cell is provided.

  The dye-sensitized solar cell according to claim 3 is characterized in that, in claim 2, the partition means is made of an electrically insulating material.

  A dye-sensitized solar cell according to claim 4 is characterized in that, in claim 2 or 3, the partition means is a partition perpendicular to the first substrate and the second substrate.

  The dye-sensitized solar cell according to claim 5 is the dye-sensitized solar cell according to any one of claims 1 to 4, wherein an electrolyte solution sealing material is interposed between peripheral edges of the first substrate and the second substrate. It is characterized by.

  A dye-sensitized solar cell according to a sixth aspect is the method according to any one of the first to fifth aspects, wherein only one of the dye-sensitized semiconductor electrode and the counter electrode of the adjacent unit cells is electrically connected. It is characterized by being.

  The dye-sensitized solar cell according to claim 7 is the dye-sensitized solar cell according to any one of claims 1 to 6, wherein the counter electrode formed on the substrate on the side irradiated with the light has light transmittance. To do.

  In the unit cells adjacent to each other in the dye-sensitized solar cell of the present invention, since the arrangement of the semiconductor electrode and the counter electrode is reversed, the conductive member required in the conventional example of FIG. It becomes unnecessary, and manufacture of a dye-sensitized solar cell becomes easy.

  In the present invention, since the arrangement of the semiconductor electrode and the counter electrode is reversed in adjacent unit cells, the direction of movement of ions in the electrolyte solution of each unit cell (accordingly, the ion concentration gradient) is determined during power generation operation. The opposite is true between adjacent unit cells. Therefore, in the present invention, it is desirable to provide partition means for preventing the electrolyte solution of adjacent unit cells from being mixed.

  The partition means is preferably made of an electrically insulating material in order to prevent a short circuit between the electrodes.

  As the partitioning means, partition walls perpendicular to the first and second substrates are suitable. This partition is merely for preventing the electrolyte solutions from being mixed with each other, and a simple structure is sufficient.

  In the present invention, it is preferable that only the semiconductor electrodes of adjacent unit cells or only the counter electrodes are made conductive. Thereby, adjacent unit cells can be easily arranged in series.

  Note that the counter electrode provided on the substrate on the side irradiated with light is preferably excellent in light transmittance.

  FIG. 1 is a schematic cross-sectional view showing an example of the dye-sensitized solar cell of the present invention.

  In this dye-sensitized solar cell, a plurality (three in the drawing) of cells (unit cells) are arranged in series.

  In this dye-sensitized solar cell, a transparent electrode 2a having a size corresponding to two cells and a transparent electrode 2b having a size corresponding to one cell are provided on the film substrate 1 as a transparent electrode 2.

  On the transparent electrode 2a, a dye-sensitized semiconductor electrode (titania electrode) 3a having a size corresponding to one cell and a counter electrode 6A having a light-transmitting size corresponding to one cell are provided. As the counter electrode 6A having optical transparency, a platinum (Pt) thin film is suitable, but is not limited thereto.

  On the film substrate 7, a counter electrode 6a having a size corresponding to one cell and an electrode 10 having a size corresponding to two cells are provided. The electrode 10 is preferably a platinum thin film, but is not limited thereto. The counter electrode 6a is disposed to face the semiconductor electrode 3a.

  On the electrode 10, a semiconductor electrode 3A having a size corresponding to one cell and a counter electrode 6b having a size corresponding to one cell are provided. The semiconductor electrode 3A is disposed to face the counter electrode 6A, and the counter electrode 6b. Is disposed opposite to the semiconductor electrode 3b.

  The constituent materials of the transparent electrodes 2a, 2b, the semiconductor electrodes 3a, 3b, 3A and the counter electrodes 6a, 6b are not particularly limited, and for example, the same materials as those in the conventional example can be used.

  The liquid sealing material 4 is interposed between the peripheral portions of the substrates 1 and 7, and the electrolyte solution 5 is sealed between the substrates 1 and 7.

  In this dye-sensitized solar cell, the semiconductor cell 3a and the counter electrode 6a constitute a first cell, the semiconductor electrode 3A and the counter electrode 6A constitute a second cell, and the semiconductor electrode 3b and the counter electrode A third cell is configured by 6b.

  The semiconductor electrode 3a of the first cell and the counter electrode 6A of the second cell are formed on the common transparent electrode 2a and are conducted through the transparent electrode 2a. The semiconductor electrode 3 </ b> A of the second cell and the counter electrode 6 b of the third cell are formed on the common electrode 10 and are conducted through the electrode 10. Accordingly, the first, second and third cells are connected in series, and an output voltage is taken out between the semiconductor electrode 2b and the counter electrode 6a. This output voltage is three times the value of one cell (unit battery).

  In this form, in order to prevent mixing of the electrolyte solutions 5 in each cell, a partition wall 9 made of an electrically insulating material is disposed between the cells as partition means. The partition wall 9 is perpendicular to the substrates 1 and 7.

  The dye-sensitized solar cell thus configured has an output voltage corresponding to three cells as described above. Although the ion concentration gradient is reversed between the first, third, and second cells, in this embodiment, the partition wall 9 prevents the electrolyte solution from being mixed between the cells, so that the power generation efficiency is high.

  This partition wall 9 is not intended for electrical connection between the electrodes as in the conductor 8 in FIG. 2, but merely for preventing the electrolyte solution from being mixed between the cells. It is good and the positional accuracy is low. Therefore, this dye-sensitized solar cell is simpler to manufacture and lower in manufacturing cost than the dye-sensitized solar cell shown in the drawing. The partition wall 9 can be formed of a photolithograph, a strip-shaped polymer film, or the like.

  When a counter electrode that does not transmit light is used as the counter electrode 6A, efficiency can be gained by reducing the area occupied by the cell in the reverse direction relative to the cell in the positive direction. The cells in the reverse direction can exhibit efficiency even though they are small because scattered light from adjacent cells in the positive direction enters.

  In the above embodiment, three cells are connected in series, but two or four or more cells may be connected in series.

  In the above embodiment, a film substrate is used, but a glass substrate or the like may be used.

It is typical sectional drawing of the dye-sensitized solar cell of this invention. It is typical sectional drawing of the conventional dye-sensitized solar cell. It is typical sectional drawing of another conventional dye-sensitized solar cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,7 Film substrate 2,2a, 2b Transparent electrode 3,3a, 3b, 3A Semiconductor electrode 4 Liquid sealing material 5 Electrolyte solution 6,6a, 6b, 6A Counter electrode 8 Conductor 9 Partition

Claims (7)

A dye-sensitized semiconductor electrode, a counter electrode provided facing the dye-sensitized semiconductor electrode, and an electrolyte solution disposed between the dye-sensitized semiconductor electrode and the counter electrode, In the dye-sensitized solar cell in which the dye-sensitized semiconductor electrode and the counter electrode are respectively provided on a substrate,
The dye-sensitized semiconductor electrode and the counter electrode are disposed on the first substrate, the counter electrode facing the dye-sensitized semiconductor electrode on the first substrate, and the first electrode on the second substrate, A plurality of unit cells are formed by arranging a dye-sensitized semiconductor electrode facing a counter electrode on the substrate of
A counter electrode provided on the first substrate and a second electrode adjacent to a unit cell comprising a dye-sensitized semiconductor electrode provided on the first substrate and a counter electrode provided on the second substrate. A unit cell comprising a dye-sensitized semiconductor electrode provided on the substrate of
A dye-sensitized solar cell, wherein each unit cell is connected in series.   2. The dye-sensitized solar cell according to claim 1, wherein partition means for separating the electrolyte solution of each unit cell is provided.   3. The dye-sensitized solar cell according to claim 2, wherein the partition means is made of an electrically insulating material.   4. The dye-sensitized solar cell according to claim 2, wherein the partitioning means is a partition perpendicular to the first substrate and the second substrate.   5. The dye-sensitized solar cell according to claim 1, wherein an electrolyte solution sealing material is interposed between peripheral edges of the first substrate and the second substrate. 6.   6. The dye-sensitized solar cell according to any one of claims 1 to 5, wherein only one of the dye-sensitized semiconductor electrode and the counter electrode of adjacent unit cells is provided in conduction. .   The dye-sensitized solar cell according to any one of claims 1 to 6, wherein the counter electrode formed on the substrate on the side irradiated with light has light transmittance.

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