JP2014044881A - Composite solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a solar cell that generates power even under low light intensity.SOLUTION: Two glass substrates on which transparent conductive films are formed are arranged so that the transparent conductive films are opposed to each other. A titanium dioxide electromotive force body and a dye-sensitization electromotive force body are aligned on one of the glass substrates, and a colorless transparent electrolyte is filled between the two glass substrates. The dye-sensitization electromotive force body is split, or the titanium dioxide electromotive force body is arranged at a center of the glass substrate, so that the dye-sensitization electromotive force body is arranged at a peripheral part of the glass substrate. Furthermore, a silicon dioxide electromotive force body is arranged on the glass substrate opposed to the glass substrate on which the titanium dioxide electromotive force body and the dye-sensitization electromotive force body are arranged. A composite solar cell outputs sufficient power even under low light intensity. Furthermore, the silicon dioxide electromotive force body is incorporated, so as to obtain a larger output current.

Description

  The present invention relates to a composite solar cell in which solar cells having different configurations are combined.

  A semiconductor solar cell using a semiconductor such as silicon has high conversion efficiency, but is expensive because a high-purity material is used.

In contrast to expensive semiconductor cells, there are solar cells using titanium dioxide (TiO ₂ ) or zinc oxide (ZnO) as relatively inexpensive solar cells.

FIG. 1A shows a basic configuration of a titanium dioxide solar cell.
In this figure, 1 and 3 are glass substrates each having an FTO (fluorine-doped tin oxide) layer 2 and an FTO layer 4, and the FTO layers 2 and 4 function as charge extraction electrodes.
5 is a titanium dioxide electromotive body made of a porous titanium dioxide sintered body, and 6 is an electrolyte. The electrolyte 6 is generally an iodine-based electrolyte in which iodine is dissolved in a potassium iodide aqueous solution.

  Electrons are excited from the porous titanium dioxide sintered body 5 by the ultraviolet light incident through the FTO transparent conductive film 2 on the glass substrate 1, and the excited electrons are taken out from the FTO transparent conductive layer 2 to the outside. It returns from the FTO transparent conductive film 4 to the porous titanium dioxide sintered body 15 via the electrolyte 6 via the load 7.

FIG. 1B shows a basic structure of a dye-sensitized solar cell (DSSC: Dye Sentitized Solar Cell) obtained by improving a titanium dioxide solar cell.
The light that can be used for the electromotive force of titanium dioxide is only ultraviolet light having a wavelength of 380 nm or less. The ultraviolet light in this wavelength region is only 4% of sunlight, and the utilization efficiency of sunlight is actually 4% at maximum. Is at most 1%, so the utilization efficiency of sunlight is very low.
The dye-sensitized titanium dioxide generator 7 in which the ruthenium complex dye is attached to the titanium dioxide generator 5 in order to expand the range of light that can be used by the titanium dioxide solar cell and increase the utilization rate of sunlight is visible light. Because the dye-sensitized solar cell can also generate electricity with a part of visible light, the utilization efficiency of sunlight is theoretically 30% (actually 10% at maximum). .

  A ruthenium complex dye is generally used as the dye to be used, but a dye other than the ruthenium complex dye may be used as long as it is a dye that generates electricity with light having a wavelength that does not contribute to the electromotive force of titanium dioxide.

  The present inventors have discovered that artificial quartz or fused silica, which is silicon dioxide, has photovoltaic ability, and proposed a silicon dioxide solar cell described in International Publication No. WO2011 / 049156.

FIG. 1 (c) shows a silicon dioxide solar cell.
In this figure, 11 and 13 are glass substrates each having an FTO film 12 and an FTO film 14, and the FTO film 12 and the FTO film 14 function as charge extraction electrodes.
15 is a silicon dioxide electromotive body consisting of silicon dioxide (SiO ₂₎ fired body obtained by mixing an electrolyte with a thickness of 0.15 to 0.20 mm.

  The titanium dioxide solar cell of FIG. 1A, the dye-sensitized solar cell of FIG. 1B, and the silicon dioxide solar cell of FIG. 1C all have iodine (LiI) aqueous solution as an electrolyte. An iodine electrolyte in which I2) is dissolved is used.

This iodine-related electrolyte has a yellowish brown color due to iodine as a component.
When the electrolyte needs to be colorless, an electrolyte having the following composition can be used.
1-ethyl-3-methylimidazolium iodide 0.4 mol, tetrabutylammonium iodide 0.4 mol, 4-tert-butyl pyridine: 0.2 mol, guanidinium isothiocyanate 0.1 mol using propylene carbonate solution as solvent Prepared.
This electrolyte is almost colorless and transparent in the visible light region when the concentration of halogen molecules is 0.0004 mol / L or less.

In addition, the following electrolytes can also be used.
A solution prepared by using 0.5 mol of lithium iodide (LiI) and 0.05 mol of metal iodine (I2) using polyethylene glycol having a molecular weight of 220 as a solvent.

Furthermore, the following electrolyte can also be used.
To increase the open electromotive force and the fill factor, 4-tert-butyl is added to a solution of 0.5 mol of lithium iodide (LiI) and 0.05 mol of metal iodine (I2) in methoxypropionitrile. Added with pyridine.

The following electrolytes have obtained the highest value.
LiI and I2, 3-methoxypropionitrile as a solvent, 1-propyl-2,3 dimethylimidazolium iodide as a room temperature molten salt that lowers viscosity and smoothes the diffusion of ions, 4-tert increases the open electromotive force by preventing reverse current A mixture of -butyl pyridine in a specified ratio.

In the case of a dye-sensitized titanium dioxide solar cell, an organic solvent that is a mixed solution of 20% by volume of acetonitrile and 80% by volume of ethylene carbonate is used in order to shorten the life of the dye when the solvent is aqueous.
In addition, an organic acid such as acetic acid or citric acid can be used as a colorless electrolyte.

International Publication WO2011 / 049156

Titanium dioxide solar cells are colorless but generate electricity only by ultraviolet light, so that the output current is not large.
On the other hand, the dye-sensitized solar cell contributes to the electromotive force of not only ultraviolet light but also visible light, so the output current is large. However, since it is colored, it cannot be used for applications that need to be colorless.
Further, even in the dye-sensitized solar cell, it is a part of ultraviolet light and visible light that contributes to electromotive force, and infrared light that is important as a light component does not contribute to electromotive force.

An object of the present invention is to provide a solar cell that is basically colorless and can obtain a sufficient current.
It is another object of the present invention to provide a solar cell that can generate electricity using infrared light that is not used.

In this application, a colorless titanium dioxide electromotive material and a colored dye-sensitized electromotive material are combined to form a composite solar cell having the following configuration.
(1) Two glass substrates on which a transparent conductive film is formed are arranged with each transparent conductive film facing each other, and a titanium dioxide electromotive body and a dye-sensitized electromotive body are disposed side by side on one side of the glass substrate. A colorless and transparent electrolyte is filled between the two glass substrates.
(2) The dye-sensitized electromotive member is divided and arranged.
(3) A silicon dioxide electromotive body is disposed on a glass substrate facing a glass substrate on which a titanium dioxide electromotive body and a dye-sensitized electromotive body are disposed.
(4) A titanium dioxide electromotive body is disposed in the central portion of the glass substrate, and a dye-sensitized electromotive body is disposed in the peripheral portion of the glass substrate.

A colorless and transparent titanium dioxide oxide generator with a small output current because it is generated only by ultraviolet light, and a dye-sensitized generator with a large output current because it is also colored and opaque but also generates visible current. The composite solar cell outputs sufficient current even under low illumination.
Furthermore, a larger output current can be obtained by combining a silicon dioxide generator that can generate a larger output current because it is colorless and transparent, and can be generated by infrared light.

The schematic diagram of the titanium dioxide solar cell of a prior art, a dye-sensitized titanium dioxide solar cell, and a silicon dioxide solar cell. 1 is a schematic diagram of a composite solar cell that is Embodiment 1. FIG. The schematic diagram of the silicon dioxide solar cell and tandem solar cell of a prior art. 4 is a schematic diagram of a composite tandem solar cell that is Embodiment 2. FIG. Application example of the composite tandem solar cell of Example 3.

  Embodiments of the invention according to this application will be described below with reference to the drawings.

FIG. 2 shows a schematic diagram of a composite solar cell configured as a combination of a titanium dioxide solar cell and a dye-sensitized solar cell in parallel as Example 1.
In (a), 1 and 3 are glass substrates each having an FTO (fluorine-doped tin oxide) layer 2 and an FTO layer 4, and the FTO layers 2 and 4 function as charge extraction electrodes.
5 is a porous titanium dioxide sintered body.
6 is an electrolyte. The colorless electrolyte shown in FIG. 1 as a prior art, 1-ethyl-3-methylimidazolium iodide 0.4 mol, tetrabutylammonium iodide 0.4 mol, 4-tert-butyl pyridine: 0 0.2 mol, guanidinium isothiocyanate 0.1 mol prepared using a propylene carbonate solution as a solvent can be used.

  7 is a dye-sensitized electromotive body in which a sensitizing dye such as a ruthenium complex dye is attached to a titanium dioxide sintered body.

In this figure, the titanium dioxide electromotive body 5 and the dye-sensitized electromotive body 7 have the same area, but the area is not limited to the same area.
Further, the titanium dioxide electromotive body 5 and the dye-sensitized electromotive body 7 can be arranged singly as shown in (a) or divided as shown in (b).
Further, the dye-sensitized electromotive body 7 can be arranged not on the same plane as the titanium dioxide electromotive body 5 but on a vertical plane or the like.

This composite solar cell has a configuration in which a colorless solar cell using a titanium dioxide electromotive body 5 and a colored solar cell using a dye-sensitized electromotive body 7 are connected in parallel.
Using this composite solar cell, a titanium dioxide electromotive material is used for a portion that is required to be colorless, and a dye-sensitized photovoltaic device is used for a portion that is not required to be colorless, Sufficient current can be obtained.

In the Japanese Patent Application No. 2011-91389 (PCT / JP2012 / 56291), the present inventors have proposed the solar cell of FIG. 3A configured by separating silicon dioxide without mixing an electrolyte.
In this figure, 11 and 13 are glass substrates each having an FTO film 12 and an FTO film 14, and the FTO film 12 and the FTO film 14 function as charge extraction electrodes.
Reference numeral 15 denotes a silicon dioxide electromotive body made of silicon dioxide.
Solar cells using silicon dioxide electromotive bodies generate electricity from ultraviolet light to visible light, and even infrared light.

Moreover, the present inventors proposed the tandem solar cell of FIG.3 (b) which has arrange | positioned the titanium dioxide electromotive body and the silicon dioxide oxide electromotive body in series in the same application.
In this figure, 21 and 23 are glass substrates each having an FTO film 22 and an FTO film 24, and the FTO film 22 and the FTO film 24 function as charge extraction electrodes.
5 is a titanium dioxide electromotive body, 15 is a silicon dioxide electromotive body, a titanium dioxide electromotive body is disposed on the light incident side, and a silicon dioxide electromotive body is disposed on the light exit side. Yes.

Furthermore, in the same application, the present inventors proposed the tandem solar cell of FIG. 3 (c) in which a dye-sensitized electromotive body and a silicon dioxide electromotive body are arranged in series.
In this figure, 21 and 23 are glass substrates each having an FTO film 22 and an FTO film 24, and the FTO film 22 and the FTO film 24 function as charge extraction electrodes.
7 is a dye-sensitized electromotive body, 15 is a silicon dioxide electromotive body, a titanium dioxide electromotive body is disposed on the light incident side, and a silicon dioxide electromotive body is disposed on the light emitting side. Yes.
This composite solar cell has a current increase of 20-50% compared to the dye-sensitized solar cell.

FIG. 4 shows a composite solar cell based on these solar cells.
In this figure, 21 and 23 are glass substrates each having an FTO film 22 and an FTO film 24, and the FTO film 22 and the FTO film 24 function as charge extraction electrodes.
5 is a titanium dioxide electromotive body, and 7 is a dye-sensitized electromotive body.
6 is an electrolyte. The colorless electrolyte shown in FIG. 1 as a prior art, 1-ethyl-3-methylimidazolium iodide 0.4 mol, tetrabutylammonium iodide 0.4 mol, 4-tert-butyl pyridine: 0 0.2 mol, guanidinium isothiocyanate 0.1 mol prepared using a propylene carbonate solution as a solvent can be used.

  Reference numeral 15 denotes a silicon dioxide electromotive body. A titanium dioxide electromotive body is disposed on the light incident side, and a silicon dioxide electromotive body is disposed on the light emitting side.

In (a), the titanium dioxide electromotive body 5 and the dye-sensitized electromotive body 7 have the same area, but the area is not limited to the same area.
Further, the titanium dioxide electromotive body 5 and the dye-sensitized electromotive body 7 can be arranged singly as shown in (a) or divided as shown in (b).
Further, the dye-sensitized electromotive body 7 can be arranged not on the same plane as the titanium dioxide electromotive body 5 but on a vertical plane or the like.

FIG. 5 shows an example of using a composite solar cell.
(A) shows an example of use of the split-arrangement composite solar cell shown in FIGS. 2 (b) and 4 (b).
(A) is an example used for a window of a building, a transportation device, etc., (b) is an example using a glass of a watch, a titanium dioxide electromotive body 5 is used in the central part, and the peripheral part. Is a composite solar cell in which a dye-sensitized electromotive body 7 is disposed.

FIG. 2C shows a cross section of the composite solar cell shown in FIG. 2B, and FIG. 4D shows a cross section of the composite solar cell shown in FIG. 4B.
Also in these cases, the dye-sensitized electromotive body 7 can be arranged not on the same plane as the titanium dioxide electromotive body 5 but on a vertical plane or the like.

  A colorless and transparent titanium dioxide oxide generator with a small output current because it is generated only by ultraviolet light, and a dye-sensitized generator with a large output current because it is also colored and opaque but also generates visible current. Combined with a solar cell and a silicon dioxide generator that can generate even larger output current because it is colorless and transparent but can be generated by infrared light, the composite cell is a variety of devices that need to be used under low illumination It is extremely useful as a power source for

1, 3, 11, 13, 21, 23 Glass substrate 2, 4, 12, 14, 22, 24 Transparent conductive film 5 Titanium dioxide oxide generator 6, 16, 26 Electrolyte 7 Dye-sensitized photovoltaic element

Claims (5)

Two glass substrates on which transparent conductive films are formed are arranged with each transparent conductive film facing each other,
A titanium dioxide electromotive material and a dye-sensitized electromotive material are arranged side by side on one side of the glass substrate,
A composite solar cell, wherein a colorless and transparent electrolyte is filled between the two glass substrates.   The composite solar cell according to claim 1, wherein the dye-sensitized photovoltaic element is divided and arranged.   Furthermore, the silicon dioxide electromotive body is arrange | positioned at the glass substrate facing the glass substrate in which the said titanium dioxide electromotive body and the dye-sensitized electromotive body are arrange | positioned, The Claim 1 or Claim 2 characterized by the above-mentioned. Composite solar cell.   The composite solar cell according to claim 1, wherein the titanium dioxide electromotive body is disposed in a central portion of the glass substrate, and the dye-sensitized electromotive body is disposed in a peripheral portion of the glass substrate. 5. The composite solar cell according to claim 4, further comprising a silicon dioxide electromotive material disposed on a glass substrate opposite to the glass substrate on which the titanium dioxide electromotive material and the dye-sensitized electromotive material are disposed. .

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