JP4647292B2 - Counter electrode of dye-sensitized solar cell and dye-sensitized solar cell using the same - Google Patents

Description

  The present invention relates to a counter electrode of a dye-sensitized solar cell and a dye-sensitized solar cell using the same.

  The dye-sensitized solar cell has been proposed since a photoelectric conversion element using dye-sensitized semiconductor fine particles was proposed (“Nature”, Vol. 353, pages 737-740, (1991)). It is attracting attention as a new solar battery that replaces batteries. Compared to silicon-based solar cells, it is possible to reduce the manufacturing cost, and is attracting attention.

Most dye-sensitized solar cells include a working electrode obtained by laminating a porous titanium oxide film on a transparent conductive layer on glass and adsorbing the surface with a sensitizing dye, an electrolyte, and a counter electrode. Most of the counter electrodes used in dye-sensitized solar cells that are known at present are made by carrying platinum on a transparent conductive material such as ITO glass. However, since platinum is a noble metal and expensive, it has been studied to use a cheaper conductive polymer and to carry it on a transparent conductive layer provided on a glass substrate.
Chemistry Letters 2002 1060-1061

In a conventional technique, when a conductive polymer is used as a counter electrode of a dye-sensitized solar cell, a conductive polymer dispersion or a monomer dispersion thereof is placed on a transparent conductive layer on a glass substrate. The method of applying, drying or polymerizing was taken. However, it is necessary to use a highly polar solvent with low solubility for the conductive polymer and its monomers, and the wettability to the base material is poor, so a limited coating method such as spin coating is required for uniform coating. Met. . Furthermore, when the electrolyte is used as a solution when assembled into a solar cell, sufficient adhesiveness is required to suppress peeling from the transparent conductive layer.
Moreover, when glass was used as the substrate, the impact resistance was low, and the impact resistance when a solar cell was obtained was also low.

  An object of the present invention is to solve the problems of the prior art. That is, the object of the present invention is to provide a counter electrode for a dye-sensitized solar cell, which is composed of a conductive polymer bonded with a substrate having high impact resistance and poor wettability with sufficiently high adhesive strength, and resistance resistance using the same. The object is to provide a dye-sensitized solar cell with high impact.

That is, the present invention provides a plastic film, a transparent conductive layer provided thereon, and Ri Do a conductive polymer layer provided on top of the transparent conductive layer, the surface energy of the transparent conductive layer is located at 40~72mN / m And a dye-sensitized solar cell counter electrode , wherein the conductive polymer layer is the outermost layer, and a method for producing the counter electrode, and a dye-sensitized solar cell using the counter electrode of the dye-sensitized solar cell. is there.

  According to the present invention, there is provided a counter electrode for a dye-sensitized solar cell that has high impact resistance and is bonded to a substrate with sufficiently high adhesive strength.

Hereinafter, the present invention will be described in detail.
[Plastic film]
The plastic film in the present invention is made of plastic. Plastics include polyester, polycarbonate, amorphous olefin, polyether, polyether ether ketone, polyphenylene ether, polymethacrylate, polystyrene, acrylic, polyamide, polyarylate, polysulfonic acid, polyethersulfone, polyarylene sulfide, phenol resin, Examples include urea resin, melamine resin, epoxy resin, diallyl phthalate, polyurethane, silicon resin, fluororesin, polyimide, polyetherimide, and polyamideimide. Of these, polyester is preferred.

  As polyester, aromatic polyester is used, and polyethylene naphthalene dicarboxylate and polyethylene terephthalate can be exemplified. In particular, polyethylene naphthalene dicarboxylate is preferred.

The thickness of the plastic film in the present invention is preferably 10 to 500 μm, more preferably 20 to 400 μm, and particularly preferably 50 to 300 μm. If the thickness is less than 10 μm, handling becomes difficult and the subsequent solar cell assembly process is hindered. A thickness of more than 500 μm is not preferable because the flexibility of the dye-sensitized solar cell is lowered.
When polyester is used as the plastic, it is preferable to use the polyester as a stretched film, particularly a biaxially stretched film from the viewpoint of mechanical strength.

[Easily adhesive layer]
A transparent conductive layer is provided on the plastic film, but an easy-adhesion layer may be provided between the plastic film and the transparent conductive layer in order to improve the adhesion between the plastic film and the transparent conductive layer. When providing an easily bonding layer, the thickness becomes like this. Preferably it is 10-200 nm, More preferably, it is 20-150 nm. If the thickness of the easy-adhesion layer is less than 10 nm, the effect of improving the adhesion is poor, which is not preferable. If the thickness exceeds 200 nm, the easy-adhesion layer tends to cause cohesive failure and the adhesion may be lowered.

  The easy adhesion layer may be provided after the plastic film is formed, or may be provided by coating during the production process of the plastic film. It is preferably provided by coating during the production process of the plastic film. In particular, when the plastic film is produced by being drawn, it may be applied before the drawing and heat setting steps are completed in the production process of the plastic film. preferable.

  Here, the plastic film before crystal orientation is completed is an unstretched film, a uniaxially oriented film in which the unstretched film is oriented in either the longitudinal direction or the transverse direction, and further in two directions, the longitudinal direction and the transverse direction. And a film that has been stretched and oriented at a low magnification (a biaxially stretched film before it is finally re-stretched in the machine direction or the transverse direction to complete oriented crystallization).

  The constituent material of the easy-adhesion layer is preferably a constituent material that exhibits excellent adhesion to both the plastic film and the transparent conductive layer. Specifically, polyester resin, acrylic resin, urethane acrylic resin, silicon acrylic resin And melamine resin and polysiloxane resin. These resins may be used alone, or two or more kinds thereof may be used as a mixture, for example.

[Hard coat layer]
Furthermore, a hard coat layer may be provided between the easy-adhesion layer and the transparent conductive layer in order to improve the adhesion between the plastic film and the transparent conductive layer, particularly the durability of the adhesion.
The hard coat layer is preferably provided by a method of coating on a plastic film provided with an easy adhesion layer. The hard coat layer is preferably composed of a material that exhibits excellent adhesion to both the easy-contact layer and the transparent conductive layer. From the viewpoint of industrial productivity, thermosetting and energy ray curable resins are acrylic. A resin component such as resin, urethane resin, silicon resin, and epoxy resin, and a mixture of these with inorganic particles such as alumina, silica, and mica are preferable. The thickness of the hard coat layer is preferably 0.01 to 20 μm, more preferably 1 to 10 μm.

[Transparent conductive layer]
In the present invention, the transparent conductive layer is formed using a conductive metal oxide. Examples thereof include fluorine-doped tin oxide, indium-tin composite oxide (ITO), indium-zinc composite oxide, metal thin films (eg, platinum, gold, silver, copper, aluminum, etc.), and carbon materials. One type of transparent conductive layer may be used, or two or more types may be laminated or combined. In particular, ITO and indium-zinc composite oxide are particularly preferable because of high light transmittance and low resistance.

The surface resistance of the transparent conductive layer is preferably 100Ω / □ or less, more preferably 40Ω / □ or less. Exceeding 100Ω / □ is not preferable because the internal resistance of the solar cell increases and current does not sufficiently flow.
The thickness of the transparent conductive layer is preferably 100 to 500 nm. If it is thinner than this, the surface resistance value cannot be lowered sufficiently, and if it is thick, the transparent conductive layer is easily broken, which is not preferable.

  The surface energy of the transparent conductive layer is preferably 40 to 72 mN / m. When the surface energy is less than 40 mN / m, it becomes difficult to apply a dispersion of conductive polymer and monomer, and when the surface energy exceeds 72 mN / m, the surface energy is applied to the film at a necessary level. This is not preferable because the surface of the transparent conductive layer may be destroyed in the step of performing.

  Means for achieving the above surface energy include, for example, (1) a method of activating the surface of a transparent conductive thin film with an acidic or alkaline solution, and (2) activation by irradiating the surface of the thin film with ultraviolet rays or an electron beam. And (3) a method of activating the surface by performing corona treatment or plasma treatment can be applied. Among these, a method of activating the surface by performing corona treatment or plasma treatment, particularly plasma treatment, is particularly preferable because high surface energy can be obtained.

[Conductive polymer layer]
Examples of the conductive polymer in the present invention include polythioephene, polypyrrole and polyaniline.
As the polythiophene, those represented by the following formula can be used. Polythiophene may be a copolymer or a mixture.

［式中、Ｒ_１、Ｒ_２はそれぞれ同一であっても異なっていてもよく、水素原子、炭素数が１〜１２の置換されていてもよいアルキル基、および炭素数が１〜６の置換されていてもよいアルコキシ基からなる群から選択されるいずれかを示す。またＲ_１とＲ_２が分子鎖で連結していても良い。］

[Wherein R ₁ and R ₂ may be the same or different from each other, a hydrogen atom, an optionally substituted alkyl group having 1 to 12 carbon atoms, and a substitution having 1 to 6 carbon atoms. Any one selected from the group consisting of optionally substituted alkoxy groups is shown. R ₁ and R ₂ may be linked by a molecular chain. ]

  Moreover, what is shown to a following formula can be used as a polypyrrole. Polypyrrole may be a copolymer or a mixture.

［式中、Ｒ_３、Ｒ_４はそれぞれ同一であっても異なっていてもよく、水素原子、炭素数が１〜１２の置換されていてもよいアルキル基、および炭素数が１〜６の置換されていてもよいアルコキシ基からなる群から選択されるいずれかを示す。］

[Wherein R ₃ and R ₄ may be the same or different from each other, a hydrogen atom, an optionally substituted alkyl group having 1 to 12 carbon atoms, and a substitution having 1 to 6 carbon atoms. Any one selected from the group consisting of optionally substituted alkoxy groups is shown. ]

  In order to form a conductive polymer layer, 1) a method of applying a dispersion containing a conductive polymer to a transparent conductive layer on a plastic film and removing the solvent, 2) a monomer of the conductive polymer and a polymerization catalyst An example is a method in which the dispersion is applied to a transparent conductive layer on a plastic film, and then polymerization is advanced to finally remove the solvent.

  The solvent of 1) and 2) may be any solvent that sufficiently disperses the conductive polymer and monomer, the polymerization catalyst, and the like, and that does not dissolve or attack the plastic film. For example, proton solvents such as water, methanol, ethanol, propanol, isopropanol, butanol, 2-butanol, t-butanol, ethylene glycol, diethylene glycol, nitrile solvents such as acetonitrile, propironitrile, 3-methoxypropironitrile, butyronitrile, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, hexamethylphosphoramide, 1,3-dimethylimidazolidinone, tetramethylurea, 1,3-dipyropyrimidazolidinone, N --Aprotic polar solvents such as methyl caprolactam, dimethyl sulfoxide, dimethyl sulfone and tetramethyl sulfone; halogen solvents such as methylene chloride, chloroform and tetrachloroethane; Rahidorofuran can be used. These solvents may be used alone or as a mixture.

  Examples of the polymerization catalyst in 2) include iron chloride, iron organic sulfonate, and hydrates thereof. The catalyst may be added in an amount sufficient to allow the reaction to proceed sufficiently. For example, the amount is 0.1 to 5 times, preferably 0.5 to 3 times the amount of the monomer. If it is less than 0.1 times, the reaction does not proceed sufficiently. This is not preferable, and if it exceeds 5 times, it is excessively large and not industrially preferable.

  In order to improve the film-forming property in 2), a polymerization controller may be added. Examples of the polymerization control agent include imidazole and aromatic oxysulfonic acid. The polymerization controller may be added in an amount sufficient to allow the polymerization reaction to proceed sufficiently while increasing the film-forming property. From this viewpoint, it is, for example, 9 times mol or less, preferably 5 times mol or less with respect to the monomer. If it exceeds 9 moles, the polymerization reaction does not proceed sufficiently, which is not preferable.

In 1), a dispersant may be used as necessary to improve dispersibility. Examples of the dispersant include sulfonic acid compounds or polymers.
The addition amount is 0.01 to 5 times mol, preferably 0.5 to 3 times mol per the number of repeating units of the conductive polymer. If the amount is less than 0.01 moles, the dispersibility is not sufficiently improved, and if it exceeds 5 moles, the internal resistance is increased and the function as a conductive polymer cannot be exhibited.

  Furthermore, you may add a binder in order to suppress peeling of the conductive polymer film obtained in 1) and 2). As the binder, for example, an acrylic resin, a urethane resin, a silicon resin, or an epoxy resin can be used. These resin components may be used alone, but can also be used as a mixture of these and inorganic particles such as alumina, silica, and mica.

  The amount of the binder to be added is preferably 5 times or less by weight based on the conductive polymer. Addition exceeding 5 times the weight is not preferable because the internal resistance increases and the function as the conductive polymer cannot be exhibited.

  In the case of these 1) and 2), the weight content of the conductive polymer and its monomer contained in the dispersion is, for example, 0.01 to 50% by weight, preferably 0.05 to 40% by weight, more preferably 0. .1 to 30% by weight. If the amount is less than 0.01% by weight, a sufficient film thickness cannot be obtained. Therefore, when used in a solar cell, electrons are not sufficiently transferred, which is not preferable. If it exceeds 50% by weight, the viscosity of the dispersion is increased, and uniform application cannot be achieved.

  The above-mentioned dispersion of the conductive polymer of 1) and the dispersion of the monomer of 2) are applied onto the transparent conductive layer by known coating methods such as spin coating, casting, spray coating, dip coating, roll coating, and bead coating. Can be performed.

  After the application, the target conductive polymer film can be formed by removing the solvent by heating and, if necessary, reducing the pressure. The temperature at this time is equal to or higher than the temperature at which the solvent volatilizes in the case of 1), and is equal to or higher than the temperature at which the polymerization proceeds and the solvent volatilizes in the case of 2).

  In the case of 2), it is preferable to remove excess polymerization catalyst after polymerization. An example of the removal method is washing. The solvent for washing may be any solvent that dissolves the polymerization catalyst and does not dissolve the conductive polymer. Preferably, water, methanol, ethanol and isopropanol are used. Moreover, it is preferable to dry after washing. The drying temperature may be lower than the temperature at which the plastic film and the conductive polymer are not deteriorated.

  The thickness of the conductive polymer layer thus obtained is preferably 0.1 to 500 nm, preferably 1 to 200 nm. If it is less than 0.1 nm, it is not preferable because the intended delivery of electrons becomes insufficient. If it exceeds 500 nm, peeling of the film or the like becomes a problem, which is not preferable.

[Creation of dye-sensitized solar cell]
In order to produce a dye-sensitized solar cell using the electrode of the present invention, a known method can be used. Specifically, for example, it can be created by the following method.

(1) Creation of porous semiconductor A transparent conductive layer is formed on a plastic film, and a porous semiconductor layer is formed thereon. The porous semiconductor layer is formed by applying a dispersion of titanium oxide crystal fine particles dispersed in a solvent such as water or alcohol on the transparent conductive layer of the electrode by spin coating, casting, spray coating, dip coating, roll coating, or beading. It can apply by apply | coating by well-known methods, such as a coating, and removing a solvent.

  In addition, for forming the porous semiconductor layer, a method of supporting a thin film of particles by electrodeposition may be used. That is, the semiconductor fine particles are added to an appropriate low-conductivity solvent such as pure water, polar organic solvents such as alcohol, acetonitrile and THF, nonpolar organic solvents such as hexane and chloroform, or a mixed solvent thereof, so that there is no aggregation. The conductive resin sheet electrode to be electrodeposited and the counter electrode are made to face each other in parallel at a constant interval, the dispersion liquid is injected into the gap, and a DC voltage is applied between the electrodes. By selecting the concentration of the dispersion and the electrode spacing, a porous semiconductor layer that is an electrodeposition film having a constant and uniform thickness can be formed on the substrate electrode.

  The coated porous semiconductor layer may be further subjected to a high temperature treatment in order to enhance the electronic contact between the semiconductor particles and improve the adhesion to the support. In addition, the semiconductor particles are irradiated with ultraviolet light or the like that the particles strongly absorb, the microwave layer is irradiated to heat the fine particle layer, and the amorphous component of the semiconductor particles is added to form a physical bond between the fine particles. Processing such as strengthening may be performed.

(2) Production of working electrode A dye is adsorbed to the porous semiconductor layer produced in (1) above. Examples of the dye include a dye having a characteristic of absorbing light in the visible light region and the infrared light region, for example, an organometallic complex dye represented by a ruthenium bipyridine complex (ruthenium complex), a cyanine dye, a coumarin dye, and a xanthene. System dyes and porphyrin dyes can be used. These are dissolved in a solvent such as alcohol or toluene to prepare a dye solution, and the porous semiconductor layer is immersed, or sprayed or applied to the porous semiconductor layer.

(3) Seal The working electrode prepared in (2) above and the counter electrode of the present invention are overlapped with a thermocompressible polyethylene film frame spacer (thickness 20 μm) sandwiched between them, and the spacer portion is heated. Crimp the electrode. Further, the edge portion is sealed with an epoxy resin adhesive.
Through a small hole for electrolyte injection provided in advance in the corner of the sheet, an aqueous electrolyte solution containing lithium iodide and iodine (molar ratio 3: 2) and 3% by weight of nylon beads having an average particle diameter of 20 μm as a spacer is injected. Thoroughly deaerate the inside and finally seal the small holes with an epoxy resin adhesive.

Next, the present invention will be described in more detail with reference to examples. In addition, each characteristic value in an example was measured with the following method.
(1) Film thickness Using a micrometer (K-402B type manufactured by Anritsu Co., Ltd.), the film thickness is measured at 10 cm intervals in the continuous film-forming direction and the width direction of the film, and the film thickness is measured at a total of 300 locations. did. The average value of the film thicknesses of the obtained 300 locations was calculated and used as the film thickness.

(2) Surface resistance value Any five points were measured using a 4-probe type surface resistivity measuring device (Made by Mitsubishi Chemical Corporation, Loresta GP), and the average value was used as a representative value.

(3) Surface energy Contact angle: θw, θy of water having a known surface energy and methylene iodide to the transparent conductive thin film using a contact angle meter (“CA-X type” manufactured by Kyowa Interface Science Co., Ltd.) It measured on 25 degreeC and 50% RH conditions. Using these measured values, the surface energy γs of the transparent conductive thin film was calculated as follows.
The surface energy γs of the transparent conductive thin film is the sum of the dispersive component γsd and the polar component γsp. That is,
γs = γsd + γsp (Formula 1)
From the Young equation,
γs = γsw + γw · cos θw (Formula 2)
γs = γsy + γy · cos θy (Formula 3)
Here, γsw is the tension acting between the transparent conductive thin film and water, γsw is the tension acting between the transparent conductive thin film and methylene iodide, γw is the surface energy of water, and γy is the surface energy of methylene iodide. It is.
From the Fowkes equation,
γ _sw = γ _s + γ _w −2 × (γ _sd · γ _wd ) ^1/2 −2 × (γ _sp · γ _wp ) ^1/2 (Formula 4)
γ _sy = γ _s + γ _y −2 × (γ _sd · γ _yd ) ^1/2 −2 × (γ _sp · γ _yp ) ^1/2 (Formula 5)
It is. Where γ _wd is the dispersive component of the surface energy of water, γ _wp is the polar component of the surface energy of water, γ _yd is the dispersive component of the surface energy of methyl iodide, and γ _yp is the surface energy of methylene iodide. It is a polar component.

By solving the simultaneous equations of Equations 1 to 5, the surface tension γ _s = γ _sd + γ _sp of the transparent conductive thin film can be calculated. At this time, the surface energy of water (γ _w ): 72.8 mN / m, the surface energy of methylene iodide (γ _y ): 50.5 mN / m, the dispersive component of the surface energy of water (γ _wd ): 21. 8 mN / m, polar component of surface energy of water (γ _wp ): 51.0 mN / m, dispersive component of surface energy of methylene iodide (γ _y d): 49.5 mN / m, surface energy of methylene iodide Polar component (γ _yp ): 1.3 mN / m was used.

(4) IV characteristics (photocurrent-voltage characteristics)
A 15 mm ² large dye-sensitized solar cell was formed, and the photovoltaic power generation efficiency was calculated by the following method. Using a solar simulator (PEC-L10) manufactured by Pexel Technologies, simulated sunlight with an incident light intensity of 100 mW / cm ² was measured in an atmosphere at a temperature of 25 ° C. and a humidity of 50%. Using a current-voltage measuring device (PECK 2400), the DC voltage applied to the system is scanned at a constant speed of 10 mV / sec, and the photocurrent output from the device is measured to measure the photocurrent-voltage characteristics. Photovoltaic efficiency was calculated.

[Example 1]
<Creation of easy-adhesion layer composition (Coating A)>
A reactor was charged with 66 parts of dimethyl 2,6-naphthalenedicarboxylate, 47 parts of dimethyl isophthalate, 8 parts of dimethyl 5-sodium sulfoisophthalate, 54 parts of ethylene glycol, and 62 parts of diethylene glycol, and 0.05 parts of tetrabutoxy titanium. Was added and heated under a nitrogen atmosphere while controlling the temperature at 230 ° C., and the produced methanol was distilled off to conduct a transesterification reaction. Subsequently, the temperature of the reaction system was gradually raised to 255 ° C., and the pressure inside the system was reduced to 1 mmHg to carry out a polycondensation reaction to obtain a polyester. 25 parts of this polyester was dissolved in 75 parts of tetrahydrofuran, and 75 parts of water was dropped into the resulting solution under high-speed stirring at 10,000 rpm to obtain a milky white dispersion. Then, this dispersion was subjected to a reduced pressure of 20 mmHg. Distillation was performed, and tetrahydrofuran was distilled off to obtain an aqueous dispersion of polyester having a solid content of 25% by weight.

  Next, 3 parts of sodium lauryl sulfonate as a surfactant and 181 parts of ion-exchanged water are charged into a four-necked flask and the temperature is raised to 60 ° C. in a nitrogen stream. Part, 0.2 part of sodium hydrogen nitrite is added, and further monomers 30.1 parts of methyl methacrylate, 21.9 parts of 2-isopropenyl-2-oxazoline, polyethylene oxide (n = 10) methacrylic acid A mixture of 39.4 parts and 8.6 parts of acrylamide was added dropwise over 3 hours while adjusting the liquid temperature to 60 to 70 ° C. After the completion of dropping, the reaction was continued with stirring while maintaining the same temperature range for 2 hours, and then cooled to obtain an acrylic aqueous dispersion having a solid content of 35% by weight.

On the other hand, 0.2% by weight of silica filler (average particle size: 100 nm) (trade name Snowtex ZL manufactured by Nissan Chemical Co., Ltd.), polyoxyethylene (n = 7) lauryl ether (Sanyo Chemical Co., Ltd.) as a wetting agent An aqueous solution containing 0.3% by weight of the trade name NAROACTY N-70) was prepared.
A coating agent A was prepared by mixing 8 parts by weight of the polyester aqueous dispersion, 7 parts by weight of the acrylic water dispersion and 85 parts by weight of the aqueous solution.

<Creation of plastic film>
Polyethylene-2,6-naphthalene dicarboxylate pellets having an intrinsic viscosity of 0.63 and containing substantially no particles are dried at 170 ° C. for 6 hours, then fed to an extruder hopper, and melted at a melting temperature of 305 ° C. Then, it was filtered through a stainless steel fine wire filter having an average opening of 17 μm, extruded through a 3 mm slit die on a rotary cooling drum having a surface temperature of 60 ° C., and rapidly cooled to obtain an unstretched film. The unstretched film thus obtained was preheated at 120 ° C., and further heated by an IR heater at 850 ° C. from above 15 mm between low-speed and high-speed rolls and stretched 3.1 times in the longitudinal direction. The easy-coating layer was formed by applying the coating agent A on one side of the film after the longitudinal stretching with a roll coater so that the coating thickness after drying was 0.25 μm.

  Subsequently, it was supplied to the tenter and laterally at 140 ° C. 3. Stretched 3 times. The obtained biaxially oriented film was heat-fixed at a temperature of 245 ° C. for 5 seconds to form a film having an intrinsic viscosity of 0.58 dl / g and a thickness of 125 μm. It was heat relaxed at a temperature of 205 ° C. to obtain a plastic film. A UV curable hard coat agent (Desolite R7501 from JSR) was applied to the easy-contact layer side of the plastic film so as to have a thickness of about 5 μm, and UV cured to form a hard coat layer.

<Transparent conductive layer formation>
On the surface on which the hard coat layer was formed, a transparent conductive layer made of ITO having a thickness of 400 nm was formed by a direct current magnetron sputtering method using an ITO target (tin concentration is 10% by weight in terms of tin dioxide). The transparent conductive layer is formed by sputtering, after the inside of the chamber is evacuated to 5 × 10 ⁻⁴ Pa before plasma discharge, and then a mixed gas of argon and oxygen (oxygen concentration is 0.5% by volume) is introduced into the chamber. Then, the pressure was set to 0.3 Pa, and 1000 W was applied to the ITO target. The surface resistance value of the transparent conductive layer was 15Ω / □, and the surface energy was 30.0 mN / m.

  Next, using a normal pressure plasma surface treatment apparatus (AP-T03-L manufactured by Sekisui Chemical Co., Ltd.), the surface of the transparent conductive layer is subjected to plasma treatment at 1 m / min under a nitrogen stream (60 L / min), and transparent A plastic film having a layer was obtained. The surface resistance value of the transparent conductive layer was 16Ω / □, and the surface energy was 70.5 mN / m.

<Formation of counter electrode>
Dispersion containing 1% by weight of PEDOT-PSS by adding isopropanol to S-300 manufactured by Agfa, which is an aqueous dispersion of polyethylene dioxythiophene (hereinafter referred to as “PEDOT-PSS”) using polystyrene sulfonic acid as a dispersant. Liquid. The PEDOT-PSS dispersion is applied onto the transparent conductive layer of the plastic film having the transparent conductive layer using a Mayer bar so that the dry thickness is 50 nm, and the counter electrode is formed by drying at 110 ° C. for 1 minute. did. The PEDOT-PSS dispersion could be applied uniformly.

<Formation of working electrode>
After thoroughly stirring the titanium oxide dispersion PECC01 manufactured by Pexel Technologies, it was applied onto the transparent conductive layer of the plastic film having the transparent conductive layer using a 100 μm doctor blade, and then at 150 ° C. in the atmosphere for 5 minutes. The porous semiconductor layer was formed by drying, and this was immersed in a 300 μM ethanol solution of ruthenium complex (Ru535bisTBA, manufactured by Solaronix) for 24 hours, and the working electrode was prepared by adsorbing the ruthenium complex on the surface.

<Creation of dye-sensitized solar cell>
The counter electrode and the working electrode are overlapped via a thermocompression-bondable polyethylene film frame spacer (thickness 20 μm), the spacer portion is heated to 120 ° C., and both electrodes are pressure-bonded. Further, the edge portion is sealed with an epoxy resin adhesive. After injecting an electrolyte solution (3-methoxypropionitrile solution containing 0.5% lithium iodide, 0.05M iodine, 0.5M tert-butylpyridine, 3% by weight of nylon beads having an average particle size of 20 μm) And sealed with an epoxy adhesive.

As a result of measuring the IV characteristics of the completed dye-sensitized solar cell (effective area 25 mm ² ), the open circuit voltage, short circuit current density, and fill factor were 0.70 V, 6.2 mA / cm ² , 0, respectively. As a result, the photovoltaic power generation efficiency was 1.4%.

[Example 2]
Similar to Example 1, a plastic film was prepared, and a hard coat, a transparent conductive layer, and a porous semiconductor layer were formed. A dye-sensitized solar cell was prepared in the same manner as in Example 1 except that the Meyer bar was changed so that the thickness when PEDOT-PSS was dried was 100 nm when the counter electrode was prepared. As a result of measuring the IV characteristics (effective area 25 mm ² ) of the completed dye-sensitized solar cell, the open circuit voltage, short circuit current density, and fill factor were 0.70 V, 7.5 mA / cm ² , 0, respectively. As a result, the photovoltaic power generation efficiency was 1.6%.

[Comparative Example 1]
As in Example 1, a plastic film was prepared and a hard coat was prepared. PEDOT-PSS was applied to the transparent conductive layer in the same manner as in Example 1 except that the sputtering process was not performed when forming the transparent conductive layer. Results The PEDOT-PSS dispersion liquid aggregated on the transparent conductive layer and could not be applied uniformly.

  The present invention can be suitably used as a counter electrode of a dye-sensitized solar cell.

Claims (3)

Plastic film, a transparent conductive layer provided thereon, and Ri Do a conductive polymer layer provided on top of the transparent conductive layer, the surface energy of the transparent conductive layer is 40~72mN / m, and the conductive The counter electrode of the dye-sensitized solar cell , in which the polymer layer is the outermost layer . A dye-sensitized solar cell using the counter electrode of the dye-sensitized solar cell according to claim 1 . Production of counter electrode of dye-sensitized solar cell comprising plastic film, transparent conductive layer provided thereon, and conductive polymer layer provided on transparent conductive layer, wherein the conductive polymer layer is the outermost layer A method of activating the surface of the transparent conductive layer, setting the surface energy of the transparent conductive layer to 40 to 72 mN / m, and providing a conductive polymer layer on the transparent conductive layer by coating A method for producing a counter electrode of a dye-sensitized solar cell, characterized in that: