KR20120065070A - Polymer electrolyte for dye-sensitized solarcell comprising peo-ppo-peo triblock copolymer - Google Patents

Abstract

The present invention relates to a polymer electrolyte for dye-sensitized solar cells using a PEO-PPO-PEO terpolymer block copolymer and a dye-sensitized solar cell using the same. The polymer electrolyte for dye-sensitized solar cells of the present invention, an electrolyte solution containing an organic solvent, a redox derivative and an additive; And an aqueous solution comprising PEO-PPO-PEO terpolymer.
According to the polymer electrolyte for dye-sensitized solar cell of the present invention and the dye-sensitized solar cell using the same, the sol-gel transition phenomenon at a specific temperature improves the ease of storage and solves the problem of leakage of liquid electrolyte and the same level as liquid electrolyte. It can represent the energy conversion efficiency of.

Description

POLYMER ELECTROLYTE FOR DYE-SENSITIZED SOLARCELL COMPRISING PEO-PPO-PEO TRIBLOCK COPOLYMER}

The present invention relates to a dye-sensitized solar cell, and more particularly to a polymer electrolyte for dye-sensitized solar cell using a PEO-PPO-PEO terpolymer block copolymer and a dye-sensitized solar cell using the same.

Recently, various researches are being conducted to replace the existing fossil fuels to solve the energy problem. In particular, extensive research is being conducted to harness natural energy such as wind, nuclear power and solar power to replace petroleum resources that will be exhausted within decades. Unlike other energy sources, solar cells using solar energy have unlimited resources and are environmentally friendly. Therefore, since the development of Se solar cells in 1983, research has been continued and silicon solar cells have been in the spotlight recently.

However, such a silicon solar cell is difficult to commercialize because of the high manufacturing cost, and there are many difficulties in improving the battery efficiency. In order to overcome this problem, the development of dye-sensitized solar cells, which are significantly cheaper to manufacture, 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.

Such dye-sensitized solar cells have the advantage of being cheaper to manufacture than conventional silicon solar cells and applicable to glass windows or glass greenhouses due to transparent electrodes, but have limited photoelectric conversion efficiency. to be.

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 consisting of a catalyst layer formed from a platinum catalyst which serves to promote a reduction reaction of an electrolyte in a liquid electrolyte on a conductive transparent substrate including a transparent substrate and a transparent conductive oxide layer formed on the transparent substrate. A liquid electrolyte is generally used as a solution in which an electrolyte is dissolved. The liquid electrolyte is placed in a sidewall made of a thermoplastic polymer resin or the like that is formed to form a space between the semiconductor electrode and the counter electrode and is in contact with both electrodes.

However, these dye-sensitized solar cells contain a liquid electrolyte, so that the stability problem of the battery module is emerging, especially the liquid electrolyte is difficult to seal and there is a problem of volatilization or leakage of the electrolyte due to the rise of the external temperature, In this case, problems such as lack of electrochemical stability occur.

In order to solve this problem, an inorganic solid electrolyte and a polymer solid electrolyte have been recently developed in place of the liquid electrolyte. However, when the solid electrolyte is used, the light transfer efficiency is lowered compared to the liquid electrolyte because the interface transfer of electrons and ions is not good. There is a problem. In addition, gel-type polymer electrolytes have been developed to solve the problems of the non-liquid electrolytes, but the gel polymer electrolytes developed to date have been improved to some extent in terms of the volatilization or leakage of the conventional liquid electrolytes. There is a disadvantage that the conversion efficiency is lowered, the polymer electrolyte cured in a gel state has a problem that is difficult to transition to the sol state.

An object of the present invention is a polymer electrolyte for dye-sensitized solar cells, including the PEO-PPO-PEO terpolymer block copolymer exhibiting a sol-gel transition phenomenon at a specific temperature to improve the ease of storage and to solve the leakage problem of liquid electrolyte and the same To provide a dye-sensitized solar cell used.

The inventors have found that when a polymer electrolyte for dye-sensitized solar cells is prepared by mixing a liquid electrolyte and a PEO-PPO-PEO terpolymer, a sol-like polymer electrolyte is capable of reversible transition to a gel-like polymer electrolyte at a specific temperature. Thus, the present invention has been completed.

In order to achieve the above object, the present invention is an electrolyte solution comprising an organic solvent, a redox derivative and an additive; And it provides a polymer electrolyte for dye-sensitized solar cell comprising an aqueous solution comprising a PEO-PPO-PEO terpolymer block copolymer.

In addition, the present invention is a dye-sensitized solar cell comprising a semiconductor electrode, a counter electrode and an electrolyte disposed in the space between the semiconductor electrode and the counter electrode,

The electrolyte is an electrolyte solution comprising an organic solvent, a redox derivative and an additive; And it provides a dye-sensitized solar cell, characterized in that the polymer electrolyte for dye-sensitized solar cell comprising an aqueous solution comprising a PEO-PPO-PEO terpolymer block copolymer.

The polymer electrolyte for dye-sensitized solar cells according to the present invention is prepared by mixing 50-90 parts by weight of an aqueous solution containing PEO-PPO-PEO terpolymer block copolymer with respect to 100 parts by weight of an electrolyte solution containing an organic solvent, an oxidation-reducing derivative and an additive. Can be.

In one embodiment of the present invention, the organic solvent is acetonitrile, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, tetrahydrofuran, 3-methoxypropionnitrile and gamma-butyro One or two or more mixed solutions selected from the group consisting of lactones can be used.

In one embodiment of the present invention, the redox derivatives include iodine; And a 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 additive may be t-butylpyridine, 2-dimethylamino pyridine and the like, but is not limited thereto.

The aqueous solution containing the PEO-PPO-PEO terpolymer block copolymer is preferably used by mixing 10 to 40% by weight PEO-PPO-PEO terpolymer block copolymer and 60 to 90% by weight of deionized water.

The present invention exhibits a sol-gel transition phenomenon at a specific temperature, which improves the ease of storage, solves the problem of leakage of the liquid electrolyte, and at the same time shows a polymer electrolyte for a dye-sensitized solar cell having the same level of energy conversion efficiency as the liquid electrolyte, and The dye-sensitized solar cell used can be provided.

1 is a view schematically showing the structure of 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. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

The present invention is an electrolyte solution comprising an organic solvent, a redox derivative and an additive; And it provides a polymer electrolyte for dye-sensitized solar cell comprising an aqueous solution comprising a PEO-PPO-PEO terpolymer block copolymer.

In one embodiment of the present invention, the dye-sensitized solar cell polymer electrolyte according to the present invention is an aqueous solution containing a PEO-PPO-PEO terpolymer block copolymer based on 100 parts by weight of an electrolyte solution containing an organic solvent, a redox derivative and an additive It is preferable to manufacture by mixing 50-90 weight part.

The electrolyte solution used in the preparation of the polymer electrolyte for dye-sensitized solar cells according to the present invention may be prepared by mixing an organic solvent, a redox derivative and an additive.

The organic solvent is one selected from the group consisting of acetonitrile, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, tetrahydrofuran, 3-methoxypropionnitrile and gamma-butyrolactone. Alternatively, two or more kinds of mixed solutions may be used, but an organic solvent used in a liquid electrolyte used in dye-sensitized solar cells may be used without limitation.

As the redox derivative, a normal redox system electrolyte composed of a halogen group anion such as iodine or bromine and a counter metal cation can be used. Iodine as the redox derivative; And 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, and the like. no.

As the additive, t-butylpyridine, 2-dimethylamino pyridine and the like may be used, but various additives may be included.

The polymer electrolyte for dye-sensitized solar cells according to the present invention is characterized in that the aqueous solution containing the PEO-PPO-PEO terpolymer block copolymer is mixed with the above-described electrolyte solution.

PEO-PPO-PEO three won block copolymer (polyethyleneoxide-polypropyleneoxide-polyethyleneoxide triblock copolymers ) are F127 by the number of PEO and _{PPO [(PEO) 98 - (} PPO) 67 - (PEO) 98, 12500g / mol] and F68 [ (PEO) _80- (PPO) _30- (PEO) ₈₀ , 8750 g / mol]. The lower critical solution temperature (LCST) can be determined by the mixing ratio of Pluronic F127 and Pluronic F68, and shows a sol-gel transition at a specific temperature.

In one embodiment of the present invention, the PEO-PPO-PEO three won block copolymer is _{F127 [(PEO) 98 - (} PPO) 67 - (PEO) 98, 12500g / mol] and F68 [(PEO) ₈₀ - ( PPO) _30- (PEO) ₈₀ , 8750g / mol] is prepared by mixing in a ratio of 7: 3 to 3: 7 by weight, it is possible to transition from sol to gel at 35 ~ 40 ℃, 35 ~ 40 ℃ When the temperature reached the following temperature, the gel phase was further changed from sol to sol.

In the present invention, to prepare a polymer electrolyte using the reversible sol-gel transition phenomenon of the PEO-PPO-PEO terpolymer block copolymer, 10 to 40% by weight of PEO-PPO-PEO terpolymer block copolymer and deionized water in the electrolyte solution A polymer electrolyte for dye-sensitized solar cells is prepared by mixing an aqueous solution comprising a PEO-PPO-PEO terpolymer block copolymer prepared by mixing 60 to 90 wt%.

As such, the present invention provides a polymer electrolyte for dye-sensitized solar cells that can exhibit a sol-gel transition phenomenon at a specific temperature by including a PEO-PPO-PEO terpolymer block copolymer, thereby storing it compared with a liquid electrolyte of a conventional dye-sensitized solar cell. It is easy to solve the problem of leakage of liquid electrolyte, and can exhibit the same level of energy conversion efficiency as liquid electrolyte.

The present invention also provides a dye-sensitized solar cell including a semiconductor electrode, a counter electrode, and an electrolyte disposed in a space between the semiconductor electrode and the counter electrode, wherein the electrolyte includes an organic solvent, an redox derivative, and an additive. solution; And it provides a dye-sensitized solar cell, characterized in that the polymer electrolyte for dye-sensitized solar cell comprising an aqueous solution comprising a PEO-PPO-PEO terpolymer block copolymer.

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

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

In an exemplary embodiment, the semiconductor electrode 100 is formed on the transparent substrate 110, the transparent conductive film 120 formed on the transparent substrate 110, and the transparent conductive film 120. It may be configured to include a photoelectrode 130.

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 is a layer formed from indium tin oxide (FTO) or indium tin oxide (ITO) doped with fluorine.

The photoelectrode 130 is formed from 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 (SnO), and dye is adsorbed. The photoelectrode 130 preferably has a thickness of 5 to 30 μm.

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-based 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.

In one embodiment of the present invention, the counter electrode 200 is disposed on the transparent substrate 210, the transparent conductive film 220 formed on the transparent substrate 210, and the transparent conductive film 220. It may be configured to include a catalyst layer 230 formed.

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 Typically, platinum catalyst may be used.

As the polymer electrolyte 300 disposed between the semiconductor electrode 100 and the counter electrode 200, the polymer electrolyte for dye-sensitized solar cells according to the present invention described above is used.

In one embodiment of the present invention, the polymer electrolyte 300 is applied to the photoelectrode 130 on which the dye on the semiconductor electrode 100 is adsorbed, and then the counter electrode 200 is opposed to each other using an adhesive. The surface can be joined. As the adhesive, a thermoplastic polymer film may be used, for example, the trade name SURLYN (manufactured by Du Pont). The thermoplastic polymer film is positioned between the two electrodes and then sealed by heat compression.

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.

[ Example  One]

(1) Fabrication of Semiconductor Electrodes

An FTO substrate having a sheet resistance of 8 Ω was cut to a size of 2 cm * 2 cm using a diamond glass cutter. Acetone, alcohol, and deionized water were used for three-stage ultrasonic cleaning. Then, the colloidal TiO ₂ nanopaste having a particle size of 20 nm was coated on the FTO substrate with an area of 0.1 cm ² and a thickness of 100 μm using a screen printer, and the temperature was increased for 1 hour from room temperature to 550 ° C. in an electric furnace. Sintering was carried out for 30 minutes. After preparing anhydrous alcohol and N719 at a concentration of 0.3mM, the sintered TiO ₂ semiconductor electrode is immersed at 40 ℃ for 18 hours to allow the dye to adsorb.

(2) Preparation of counter electrode

An FTO substrate having a sheet resistance of 8 Ω was cut to a size of 2 cm * 2 cm using a diamond glass cutter. Acetone, alcohol, and deionized water were used to wash the ultrasonic waves in three steps, and then Pt solution was applied in a dropping manner. The Pt solution used was prepared by adding ₂ -propanol and H ₂ PtCl ₆ ˜6H ₂ O. The electrode coated with Pt was dried at 60 ° C. for 5 minutes and then sintered at 400 ° C. for 30 minutes through a temperature raising step of 1 hour to prepare a counter electrode.

(3) Preparation of Polymer Electrolyte

An electrolyte solution was prepared by mixing 3-methoxy propionitrile, 0.1M LiI, 0.05MI ₂ , 0.3M 1-hexylpyridinium iodide, and 0.3M 0.5M t-butyl pyridine for 15 minutes. Thereafter, 30 wt% of pluronic F127 and pluronic F68 were mixed in deionized water at a ratio of 7: 3 to prepare an aqueous solution including the PEO-PPO-PEO terpolymer block copolymer. Used. Thereafter, the electrolyte solution and the aqueous solution including the PEO-PPO-PEO terpolymer block copolymer were mixed at a ratio of 100: 80 and stirred for 3 hours to prepare a polymer electrolyte.

(4) Manufacture of Dye-Sensitized Solar Cell

The polymer electrolyte was applied to an area of 0.1 cm ² on the photoelectrode on which the dye of the semiconductor electrode was adsorbed using a screen printer, and then the counter electrode was joined to face each other. After forming a thermoplastic polymer layer having a thickness of about 60 μm formed of SURLYN (manufactured by Du Pont) on the joint surface of the semiconductor electrode and the counter electrode, the dye-sensitized solar cell was manufactured by sintering at 100 to 130 ° C. for 5 minutes.

[ Example  2]

A dye-sensitized solar cell was manufactured in the same manner as in Example 1, except that the electrolyte solution and the aqueous solution including the PEO-PPO-PEO terpolymer block copolymer were mixed at a ratio of 100: 70 by weight.

[ Comparative example  One]

A dye-sensitized solar cell was manufactured in the same manner as in Example 1, except that the electrolyte solution used in preparing the polymer electrolyte of Example 1 was used as the electrolyte.

[ Test Example  One]

As a result of confirming whether the electrolyte leaked through the long-term stability test of the electrolyte for the dye-sensitized solar cells prepared in Examples 1, 2 and Comparative Example 1 it was confirmed that the operation without leakage of the electrolyte for 200 hours.

[ Test Example  2]

The light conversion efficiency of the dye-sensitized solar cells prepared in Examples 1 and 2 and Comparative Example 1 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 1 below.

division Current density
(mA / cm ² ) Voltage (V) Fill factor Optical conversion efficiency (%) Example 1 13.18 0.66 0.61 5.37 Example 2 13.80 0.59 0.63 5.14 Comparative Example 1 13.31 0.61 0.61 5.01

Through the results of Table 1, the dye-sensitized solar cell using the polymer electrolyte of Examples 1 and 2 according to the present invention shows an equivalent or superior electrical characteristics compared to the dye-sensitized solar cell of Comparative Example 1 using a liquid electrolyte. You can check it.

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: polymer electrolyte 400: side wall

Claims (14)

An electrolyte solution comprising an organic solvent, a redox derivative and an additive; And a polymer electrolyte for dye-sensitized solar cell comprising an aqueous solution containing PEO-PPO-PEO terpolymer block copolymer.
The method according to claim 1,
The dye-sensitized solar cell polymer electrolyte is prepared by mixing 50 to 90 parts by weight of an aqueous solution containing a PEO-PPO-PEO terpolymer block copolymer based on 100 parts by weight of an electrolyte solution including an organic solvent, an oxidation-reducing derivative and an additive. Polymer electrolyte for dye-sensitized solar cell, characterized in that.
The method according to claim 1,
The organic solvent is one or more selected from the group consisting of acetonitrile, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, tetrahydrofuran, 3-methoxypropionnitrile and gamma-butyrolactone. A polymer electrolyte for dye-sensitized solar cells, characterized in that at least two kinds of mixed solution.
The method according to claim 1,
The redox derivative is iodine; And a mixture of 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. Electrolyte.
The method according to claim 1,
The additive is a polymer electrolyte for dye-sensitized solar cells, characterized in that t-butylpyridine or 2-dimethylamino pyridine.
The method according to claim 1,
The aqueous solution containing the PEO-PPO-PEO terpolymer block copolymer is a polymer for dye-sensitized solar cell, characterized in that prepared by mixing 10-40% by weight PEO-PPO-PEO terpolymer block copolymer and 60-90% by weight of deionized water Electrolyte.
The method of claim 6,
Wherein the PEO-PPO-PEO three won block copolymer _{(PEO) 98 - (PPO)} 67 - (PEO) 98 and _{(PEO) 80 - (PPO)} 30 - a _{(PEO) 80 7:? 3} 3: 7 weight ratio A polymer electrolyte for dye-sensitized solar cells, characterized in that prepared by mixing.
A dye-sensitized solar cell comprising a semiconductor electrode, a counter electrode, and an electrolyte disposed in a space between the semiconductor electrode and the counter electrode,
The electrolyte is an electrolyte solution comprising an organic solvent, a redox derivative and an additive; And dye-sensitized solar cell, characterized in that the polymer electrolyte for dye-sensitized solar cell comprising an aqueous solution containing PEO-PPO-PEO terpolymer block copolymer.
The method according to claim 8,
The dye-sensitized solar cell polymer electrolyte is prepared by mixing 50-90 parts by weight of an aqueous solution containing PEO-PPO-PEO terpolymer block copolymer based on 100 parts by weight of an electrolyte solution containing an organic solvent, an oxidation-reduction derivative and an additive. Dye-sensitized solar cell, characterized in that.
The method according to claim 8,
The organic solvent is one or more 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, characterized in that two or more kinds of mixed solution.
The method according to claim 8,
The redox derivative is iodine; And 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 according to claim 8,
The additive is a dye-sensitized solar cell, characterized in that t-butylpyridine or 2-dimethylamino pyridine.
The method according to claim 8,
The aqueous solution containing the PEO-PPO-PEO terpolymer block copolymer is a dye-sensitized solar cell, characterized in that prepared by mixing 10 to 40% by weight PEO-PPO-PEO terpolymer block copolymer and 60 to 90% by weight deionized water.
The method according to claim 13,
Wherein the PEO-PPO-PEO three won block copolymer _{(PEO) 98 - (PPO)} 67 - (PEO) 98 and _{(PEO) 80 - (PPO)} 30 - a _{(PEO) 80 7:? 3} 3: 7 weight ratio Dye-sensitized solar cell, characterized in that prepared by mixing.

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