KR20130142423A - Electrolyte for dye-sensitized solarcell - Google Patents

Abstract

The present invention relates to an electrolyte for a dye-sensitized solar cell and the dye-sensitized solar cell including the same. The electrolyte for a dye-sensitized solar cell contains an organic solvent, an oxidation-reduction inducer, and a compound denoted by chemical formula 1. The electrolyte for a dye-sensitized solar cell prevents the separation of dye absorbed to a working electrode and the oxidation of a counter electrode by moisture inside the electrolyte and moisture applied from the outside to prevent the deterioration of functions after long-term use and to improve photoelectric transformation efficiency. [Reference numerals] (AA) Sunlight

Description

Electrolyte for dye-sensitized solar cell {ELECTROLYTE FOR DYE-SENSITIZED SOLARCELL}

The present invention relates to a dye-sensitized solar cell, and more particularly, an electrolyte of a dye-sensitized solar cell which can improve the efficiency of the cell by preventing dye detachment and electrode oxidation by moisture present in the electrolyte and water penetrating from the outside. And it relates to a dye-sensitized solar cell comprising the same.

Recently, a variety of researches are being conducted to replace existing fossil fuels in order to solve the energy problems faced. Extensive research is underway to utilize natural energy sources such as wind, nuclear, and solar power to replace petroleum resources that will be depleted within decades. Among these solar cells, unlike other energy sources, the resources are infinite and environmentally friendly. So, since the development of Se solar cells in 1983, steady research has been continued, and silicon solar cells are in the spotlight recently.

However, since such a silicon solar cell is extremely expensive to manufacture, it is difficult to put it into practical use, and it is difficult to improve the battery efficiency. In order to overcome such problems, development of a dye-sensitized solar cell having a remarkably low manufacturing cost has been actively studied.

Dye-sensitized solar cells, developed in 1991 by Gratzel et al., Switzerland, are photosensitive dye molecules capable of absorbing visible light to produce electron-hole pairs, and nanocrystals that deliver the resulting electrons. A photoelectrochemical solar cell using an oxide semiconductor electrode made of oxidized titanium oxide particles, also called a dye-sensitized solar cell or a wet solar cell. Such a solar cell has a feature of having a photoelectric conversion efficiency that is simple in manufacturing process, low in manufacturing cost, and practically usable as compared with a silicon type solar cell, and many studies have been conducted on this.

In general, the dye-sensitized solar cell comprises a semiconductor electrode, a counter electrode, a liquid electrolyte. The semiconductor electrode is a porous nano oxide layer on a transparent substrate and a transparent conductive oxide layer formed on the transparent substrate, for example, a porous nano oxide layer on a conductive transparent substrate including fluorine-doped tin oxide (FTO) or indium tin oxide (ITO). Has a structure in which dye is adsorbed. The counter electrode has a structure in which a platinum catalyst layer is formed on a conductive transparent substrate including a transparent substrate and a transparent conductive oxide layer formed on the transparent substrate to promote a reduction reaction of the electrolyte in the liquid electrolyte. In the liquid electrolyte, a solution in which an electrolyte is dissolved is generally used. The liquid electrolyte is disposed between the semiconductor electrode and the counter electrode to be in contact with both electrodes electrochemically. Here, a sidewall made of a thermoplastic polymer resin or the like is formed between the semiconductor electrode and the counter electrode to form a space in which the electrolyte is injected between the semiconductor electrode and the counter electrode.

Such dye-sensitized solar cells are attracting attention because they are cheaper to manufacture than conventional silicon solar cells and can be applied to glass windows or glass greenhouses due to transparent electrodes, but they are practically applied due to their low photoelectric conversion efficiency. There is a limit.

Accordingly, researches for improving the photoelectric conversion efficiency of dye-sensitized solar cells have been conducted from various viewpoints, and the present invention provides a dye by preventing dye desorption and electrode deterioration caused by moisture in the electrolyte or water introduced from the outside. To improve the photoelectric conversion efficiency of the sensitized solar cell.

An object of the present invention is an electrolyte of a dye-sensitized solar cell that can prevent desorption of dye adsorbed to the working electrode and oxidation of the counter electrode by moisture present in the electrolyte and moisture introduced from the outside, thereby preventing performance deterioration in long-term use. It is to provide a dye-sensitized solar cell comprising the same.

The present invention to achieve the above object, an organic solvent; Oxidation-reduction derivatives; And it provides a dye-sensitized solar cell electrolyte comprising a compound represented by the formula (1).

[Formula 1]

The organic solvent may be selected from the group consisting of acetonitrile, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, tetrahydrofuran, 3-methoxypropionnitrile and gamma-butyrolactone. However, the present invention is not limited thereto.

The redox derivative is iodine; And at least one material selected from the group consisting of lithium iodide, sodium iodide, potassium iodide, lithium bromide, sodium bromide, potassium bromide, quaternary ammonium salts, imidazolium salts and pyridinium salts. However, the present invention is not limited thereto.

The electrolyte for dye-sensitized solar cells of the present invention may further include an additive selected from the group consisting of t-butylpyridine and 2-dimethylamino pyridine.

The dye-sensitized solar cell electrolyte of the present invention may further include a supporting electrolyte selected from the group consisting of imidazolium-based iodide, pyridinium-based iodide, and pyrrolinium-based iodide.

The content of the compound of Formula 1 is preferably 1.0 to 5.0 parts by weight based on 100 parts by weight of the electrolyte.

The electrolyte for a dye-sensitized solar cell of the present invention is a compound represented by the following formula (2), PMMA resin-containing compound, Benzophenone compound, Benzotriazole compound, Salicylate compound, Cyanoacrylate compound, Oxanilide compound, Hindered amine (HALS) compound It may further comprise a light absorber selected from the group consisting of.

(2)

The present invention also provides a dye-sensitized solar cell comprising the electrolyte.

According to the dye-sensitized solar cell electrolyte of the present invention, it is possible to prevent desorption of dye adsorbed to the working electrode and oxidation of the counter electrode due to moisture present in the electrolyte and moisture introduced from the outside, thereby preventing deterioration of performance during long-term use. Photoelectric conversion efficiency can be improved.

1 is a view schematically showing the structure of a dye-sensitized solar cell according to an embodiment of the present invention.
2 is a photograph showing the effect of moisture in the electrolyte on the dye and the electrode.
3 is a flowchart illustrating a method of manufacturing a dye-sensitized solar cell according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

1 is a view schematically showing the structure of a dye-sensitized solar cell according to an embodiment of the present invention. Referring to the dye-sensitized solar cell of the present invention with reference to Figure 1 as follows.

The dye-sensitized solar cell of the present invention includes a semiconductor electrode 100, a counter electrode 200, and an electrolyte 300 interposed between the semiconductor electrode 100 and the counter electrode 200.

The semiconductor electrode 100 includes a transparent substrate 110, a transparent conductive film 120 formed on the transparent substrate 110, and a photoelectrode 130 formed on the transparent conductive film 120. Can be configured.

The transparent substrate 110 is polyethersulfone, polyacrylate, polyetherimide, polyethylene naphthalate, polyethylene terephthalate, polyphenylene sulfide, polyarylate, polyimide, polycarbonate, cellulose triacetate and cellulose acetate propio It may be a plastic material or a glass material containing at least one selected from the group consisting of nates.

The transparent conductive layer 120 may be formed of indium tin oxide (FTO) or indium tin oxide (ITO) doped with fluorine.

The photoelectrode 130 may be formed of a composition including at least one metal oxide selected from the group consisting of titanium dioxide (TiO ₂ ), tin dioxide (SnO ₂ ), and zinc oxide (ZnO), and the photoelectrode 130 ) The dye is adsorbed. It is preferable that the thickness of the photoelectrode 130 is 5-30 micrometers.

The dye may be adsorbed using a solution containing a ruthenium complex or an organic dye. As dyes, ruthenium complexes, including ruthenium complexes, which can absorb visible light, and any dyes capable of improving long-wavelength absorption in visible light to improve efficiency and efficient electron emission can be used. to be. Specifically, xanthine-based dyes such as rhodamine B, rosebengal, eosin, erythrosin and the like; Cyanine-based dyes such as quinocyanine and cryptocyanine; Basic dyes such as phenosafranin, cabrioblue, thiocin and methylene blue; Porphyrin compounds such as chlorophyll, zinc porphyrin and magnesium porphyrin; Other azo dyes; Phthalocyanine compounds; Anthraquinone dyes; Or polycyclic quinone dye etc. can be used individually or in mixture of 2 or more types.

Meanwhile, the counter electrode 200 includes a transparent substrate 210, a transparent conductive film 220 formed on the transparent substrate 210, and a catalyst layer 230 formed on the transparent conductive film 220. Can be configured.

The transparent substrate 210 and the transparent conductive film 220 may be the same as mentioned in the semiconductor electrode 100, the catalyst layer 230 may be used a catalyst that serves to promote the reduction reaction of the electrolyte And representatively, a platinum catalyst may be used.

The electrolyte 300 disposed between the semiconductor electrode 100 and the counter electrode 200 includes an organic solvent, an oxidation-reduction derivative, and a compound represented by the following Chemical Formula 1.

As the organic solvent, for example, acetonitrile, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, tetrahydrofuran, 3-methoxypropionnitrile, gamma-butyrolactone, and the like may be used.

The redox derivatives are for example iodine; And at least one selected from the group consisting of lithium iodide, sodium iodide, potassium iodide, lithium bromide, sodium bromide, potassium bromide, quaternary ammonium salts, imidazolium salts and pyridinium salts.

The electrolyte 300 includes a compound represented by Chemical Formula 1 in addition to an organic solvent and a redox derivative. The electrolyte of the dye-sensitized solar cell may include some moisture due to moisture contained in the constituent materials or moisture introduced through the air during the manufacturing process. In the long term, the moisture contained in the electrolyte desorbs the dye adsorbed onto the TiO 2 electrode surface and oxidizes the Pt electrode. Therefore, the dye-sensitized solar cell electrolyte of the present invention includes pyridine to remove or reduce moisture in the electrolyte, thereby preventing dye detachment and Pt electrode oxidation during long-term use.

2 is a photograph showing the effect of moisture in the electrolyte on the dye and the electrode. 2A is a photograph showing a state in which the dye of the TiO ₂ electrode is detached by the moisture in the electrolyte, B is a photograph showing the oxidized state of the Pt electrode by the moisture in the electrolyte. In FIG. 2A, the color faded portion is a portion from which the dye is detached, and in FIG. 2B, the black portion is a phenomenon in which Pt is oxidized. C shows the electrode with 20% moisture and D shows the electrode without moisture. In the case of C, it can be seen that the color is lighter due to desorption of the dye by moisture.

The content of the compound represented by Formula 1 in the electrolyte 300 is preferably 1.0 to 5.0 parts by weight based on 100 parts by weight of the electrolyte. If the content exceeds 5.0 parts by weight, the function of the electrolyte may be impaired, and if it is less than 1.0, it is difficult to expect a sufficient efficiency improvement by water absorption in the electrolyte.

In addition, additives such as t-butylpyridine or 2-dimethylamino pyridine may be further added to the dye-sensitized solar cell of the present invention.

The additive is preferably added in the range of 1 to 7 times the weight of pyridine.

In addition, the dye-sensitized solar cell of the present invention may further comprise a supporting electrolyte in addition to the organic solvent, redox derivatives, pyridine and additives, the supporting electrolyte is imidazolium-based iodide, pyridinium-based iodide or Pyrrolinium-based iodide and the like can be used. Specific examples thereof include 1-ethyl-3-methylimidazolium iodide, 1-methyl-3-methylimidazolium iodide, and 1-methyl-3-methylimidazolium iodide. ) Or 1-butylpyridinium iodide (1-Butylpyridinium iodide) and the like.

In addition, the dye-sensitized solar cell of the present invention may further include a light absorber. A light absorber is a material that absorbs light of a certain wavelength to cause rotation, vibration, and translational movement of atoms and molecules, and emits energy and heat as the motion of these materials occurs.

When the light absorbing agent is introduced into the electrolyte, light corresponding to the vibration level energy difference is incident to vibrate motion of the ions and molecules in the electrolyte, so that the movement of the ions and molecules is accelerated. Ions are transferred.

As the light absorbing agent, the compound of Formula 1 may be, for example, PMMA resin-containing compound, Benzophenone compound, Benzotriazole compound, Salicylate compound, Cyanoacrylate compound, Oxanilide compound, Hindered amine (HALS) compound, Metal complex salt light Purification can be used. They do not react with existing liquid electrolyte components and can be prepared by simple mixing without a separate process.

The content of the light absorbing agent in the electrolyte 300 is preferably 0.05 to 5.0 parts by weight based on 100 parts by weight of the electrolyte. When the content of the light absorbent exceeds 5.0 parts by weight, the transparency of the battery is reduced, and thus the transmittance of light is lowered. When the content of the light absorber is less than 0.05, it is difficult to expect an improvement in light conversion efficiency by activation of an electrolyte due to the addition of the light absorber.

2 is a flowchart illustrating a method of manufacturing a dye-sensitized solar cell according to an embodiment of the present invention. Referring to Figure 2 describes the manufacturing method of the dye-sensitized solar cell of the present invention.

Method for manufacturing a dye-sensitized solar cell according to the present invention comprises the steps of manufacturing the semiconductor electrode 100, manufacturing the counter electrode 200, attaching the semiconductor electrode 100 and the counter electrode 200, the semiconductor electrode And injecting an electrolyte 300 between the 100 and the counter electrode 200.

The manufacturing of the semiconductor electrode 100 may include preparing a transparent substrate 110 and forming a transparent conductive film 120 on the prepared transparent substrate 110; Forming a photoelectrode 130 by applying a composition including a metal oxide on the formed transparent conductive film 120; And adsorbing the dye by applying a solution in which the dye is dissolved to the formed photoelectrode 130.

Specifically, first, after preparing the transparent substrate 110, the indium tin oxide or indium tin oxide doped with a transparent conductive oxide fluorine doped on the upper portion of the transparent substrate 110 using an adhesive or a sputtering method It may be coated to form a transparent conductive film (120). Next, in order to form the photoelectrode 130, after preparing a coating composition comprising at least one metal oxide selected from the group consisting of titanium dioxide (TiO ₂ ), tin dioxide (SnO ₂ ) and zinc oxide (ZnO) The photoelectrode 130 may be formed by applying a coating composition to the upper portion of the formed transparent conductive film 120 by a doctor blade method and performing heat treatment. Next, in order to adsorb the dye to the metal oxide of the formed photoelectrode 130, the dye is dissolved in a solvent to prepare a dye solution. Then, the substrate on which the photoelectrode 130 is formed is immersed and dried. The dye may be adsorbed.

The manufacturing of the counter electrode 200 may include preparing a transparent substrate 210; Forming a transparent conductive film 220 on the prepared transparent substrate 210; And forming a catalyst layer 230 on the formed transparent conductive film 220.

Specifically, first, after preparing the transparent substrate 210, indium tin oxide or indium tin oxide doped with a transparent conductive oxide fluorine doped on top of the transparent substrate 210 using an adhesive or coated by a sputtering method The transparent conductive film 220 can be formed. Next, a platinum paste may be applied to the upper portion of the transparent conductive film 220 and then heat-treated to form a platinum catalyst layer. In this case, the platinum catalyst layer may be formed using a doctor blade method, a sputtering method, a chemical vapor deposition method, a vapor deposition method, a thermal oxidation method, an electrochemical deposition method, etc. using a screen printer.

Next, the semiconductor electrode 100 and the counter electrode 200 are opposed to each other and joined. The junction between the semiconductor electrode 100 and the counter electrode 200 is coated with a thermoplastic polymer such as SURLYN (manufactured by Du Pont) on the joint surface of the semiconductor electrode 100 (or counter electrode 200), and then the counter electrode 200. (Or the semiconductor electrode 100) by placing and heat treatment.

Next, after preparing a liquid electrolyte by mixing an organic solvent, a redox derivative, pyridine, and the like, the prepared liquid electrolyte is injected and sealed between the semiconductor electrode 100 and the counter electrode 200. Encapsulants may be used to seal the liquid electrolyte.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

Test Example  One

Electrolyte A was prepared by mixing 0.15M iodine, 0.6M 1,3-dimethylididazolium iodine, 0.5M t-butylpyridine, 0.1M guanidinethiocyanate, 3-methoxypropionnitrile (the above in Electrolyte A) The concentration of the components is based on the total liquid electrolyte). After adding 5% by weight of H ₂ O to Electrolyte A, the moisture content of 5% by weight of pyridine and when it was not was measured. The measurement results are shown in Table 1 below.

Electrolyte A + 5% H ₂ O

Electrolyte A + 5% H ₂ O + 5% Pyridine
Moisture content
2832.0 ppm (0.28%)
2713.2 ppm (0.27%)

When the pyridine is added as shown in Table 1, it can be seen that the water content decreases as the pyridine is added to the electrolyte through a 0.01% decrease in the water content.

Test Example  2

Electrolyte B was prepared by mixing 0.15M iodine, 0.6M 1,3-dimethylididazolium iodine, 0.5M t-butylpyridine, 0.1M guanidinethiocyanate, 3-methoxypropionitrile (the above in electrolyte B). The concentration of the components is based on the total liquid electrolyte). The moisture content was measured when 2 wt% pyridine was added thereto and when it was not. The measurement results are shown in Table 2 below.

Electrolyte B

Electrolyte B + 5% Pyridine
Moisture content
435.1 ppm (0.04%)
314.3 ppm (0.03%)

When the pyridine is added as shown in Table 2, it can be seen that the water content decreases as the pyridine is added to the electrolyte through a 0.01% decrease in the water content.

Test Example  3 (production of dye-sensitized solar cell)

(1) Fabrication of Semiconductor Electrodes

After cutting the FTO substrate having a sheet resistance of 8Ω using a diamond glass cutter, three-stage ultrasonic cleaning was performed using deionized water, alcohol, and acetone. Then, a colloidal TiO ₂ nano paste having a particle size of 20 nm was coated on the FTO substrate with an area of 8 mm * 87 mm and a thickness of 80 μm using a screen printer, and then heated in an electric furnace for 1 hour from room temperature to 550 ° C. Sintering was carried out for 30 minutes. Since anhydrous alcohol and ruthenium-based dye N719 (Taiwan, EVERLIGHT) was prepared at a concentration of 0.3 mM, the sintered TiO ₂ semiconductor electrode was immersed at 40 ° C. for 18 hours to allow the dye to adsorb.

(2) Preparation of counter electrode

After cutting the FTO substrate having a sheet resistance of 8Ω using a diamond glass cutter, an electrolyte injection hole was formed, and then three-stage ultrasonic cleaning was performed using deionized water, alcohol, and acetone. Thereafter, Pt paste (Dysol) was applied using a screen printer, and the counter electrode was manufactured by sintering for 30 minutes in an electric furnace through a temperature raising step of 1 hour from room temperature to 400 ° C.

(3) Preparation of Electrolyte

a. In Test Example 2, an electrolyte prepared by adding pyridine was used (Example 1).

b. In Test Example 2, an electrolyte prepared without adding pyridine was used (Comparative Example 1).

c. An electrolyte prepared by adding 20% H 2 O and 2% Pyridine to the electrolyte B of Test Example 2 was used (Example 2).

d. An electrolyte prepared by adding 20% H ₂ O to Electrolyte B of Test Example 2 was used (Example 2).

(4) Manufacture of Dye-Sensitized Solar Cell

Surlyn (Dupont) having a thickness of about 60 μm was formed on the junction surface of the semiconductor electrode and the counter electrode, and then the electrode was bonded by sintering at 100 to 140 ° C. for 1 to 4 minutes. Next, after the electrolyte was injected between the semiconductor electrode and the counter electrode through the electrolyte injection hole to seal the injection hole using a PI tape to manufacture a dye-sensitized solar cell.

< Evaluation example  1>

After the aging for 48 hours for the dye-sensitized solar cells prepared in Examples 1, 2 and Comparative Examples 1, 2, the cell was exposed to the outside to perform an outdoor test. Long-term stability of the electrolyte was evaluated by the outdoor test, and as a result of checking the leakage of the electrolyte, it was confirmed that it operated without leakage of the electrolyte for 360 hours.

< Evaluation example  2>

The light conversion efficiency of the dye-sensitized solar cells prepared in Examples 1 and 2 and Comparative Examples 1 and 2 was evaluated by the following method.

Photovoltaic properties were observed by measuring the photovoltage and photocurrent, and the light conversion efficiency (ηe) was obtained using the current density (Jsc), the voltage (Voc), and the filling factor (ff) obtained through the photovoltaic characteristics. Equation 1 below was used to calculate the light conversion efficiency. In this case, a xenon lamp (Oriel) was used as the light source, and the solar condition (AM 1.5) of the xenon lamp was corrected using a standard solar cell.

[Equation 1]

ηe = (Voc × Jsc × ff) / (Pine)

Where (Pine) represents 100 mW / cm 2 (1 sun)

The values measured through the above process are shown in Table 3 below.

division Current density (mA / cm 2) Voltage (V) Fill factor Optical conversion efficiency (%) Example 1 (0day) 10.469 0.724 61.0 4.618 Example 2 (0day) 7.616 0.700 66.8 3.562 Comparative Example 1 (0 day) 10.630 0.707 59.7 4.487 Comparative Example 2 (0day) 7.372 0.685 65.7 3.319 Example 1 (15day) 10.916 0.741 63.3 5.123 Example 2 (15day) 8.171 0.708 64.4 3.703 Comparative Example 1 (15day) 11.158 0.740 61.0 5.039 Comparative Example 2 (15day) 8.565 0.699 58.1 3.476

Through the results of Table 3, the dye-sensitized solar cell using a liquid electrolyte of Example 2 was added to 2% Pyridine embodiment 1, 20% H ₂ O and 2% of Pyridine was added at a liquid electrolyte prepared 2% Compared with the dye-sensitized solar cell of Comparative Example 1, 20% H ₂ O added Comparative Example 1 without the addition of pyridine, the current density (Jsc), voltage (Voc) and fill factor (ff) is very excellent, Due to this, it can be seen that 2% Pyridine to actively perform the cell reaction in the electrolyte with high light conversion efficiency.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the claims, the detailed description of the invention, and the accompanying drawings. Naturally, it belongs to the scope of the invention.

100: semiconductor electrode 110: transparent substrate
120: transparent conductive film 130: photoelectrode
200: counter electrode 210: transparent substrate
220: transparent conductive film 230: catalyst layer
300: electrolyte 400: sidewalls

Claims (8)

Organic solvent;
Oxidation-reduction derivatives; And
The dye-sensitized solar cell electrolyte comprising a compound represented by the formula (1).
[Chemical Formula 1]

The method of claim 1,
The organic solvent is selected from the group consisting of acetonitrile, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, tetrahydrofuran, 3-methoxypropionnitrile and gamma-butyrolactone. Dye-sensitized solar cell electrolyte.
The method of claim 1,
The oxidation-reduction derivatives include iodine; And at least one mixture selected from the group consisting of lithium iodide, sodium iodide, potassium iodide, lithium bromide, sodium bromide, potassium bromide, quaternary ammonium salts, imidazolium salts and pyridinium salts. .
The method of claim 1,
A dye-sensitized solar cell electrolyte further comprising an additive selected from the group consisting of t-butylpyridine and 2-dimethylamino pyridine.
The method of claim 1,
An electrolyte for dye-sensitized solar cells, further comprising a supporting electrolyte selected from the group consisting of imidazolium-based iodide, pyridinium-based iodide, and pyrrolinium-based iodide.
The method of claim 1,
The content of the compound of Formula 1 is a dye-sensitized solar cell electrolyte, characterized in that 1.0 to 5.0 parts by weight based on 100 parts by weight of the electrolyte.
The method of claim 1,
A light absorber selected from the group consisting of a compound represented by Formula 2, a PMMA resin-containing compound, a Benzophenone compound, a Benzotriazole compound, a Salicylate compound, a Cyanoacrylate compound, an Oxanilide compound, and a Hindered amine (HALS) compound Dye-sensitized solar cell electrolyte comprising a.

(2)

A dye-sensitized solar cell comprising an electrolyte selected from claims 1 to 7.

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