WO2012057472A2

WO2012057472A2 - Method for manufacturing a photoelectrode, and solar cell including a photoelectrode manufactured by the method

Info

Publication number: WO2012057472A2
Application number: PCT/KR2011/007874
Authority: WO
Inventors: 김은경; 김종학; 김정훈; 고종관
Original assignee: 연세대학교 산학협력단
Priority date: 2010-10-25
Filing date: 2011-10-24
Publication date: 2012-05-03
Also published as: KR101073118B1; WO2012057472A3

Abstract

The present invention relates to a method for manufacturing a photoelectrode, and to a solar cell including a photoelectrode manufactured by the method. The method for manufacturing a photoelectrode includes: a step of adsorbing a dye onto a porous metal-oxide thin film; a step of impregnating the dye-adsorbed porous metal-oxide thin film with a conductive polymer dissolved in a solvent; and a step of synthesizing the conductive polymer through solid-state thermal polymerization. The manufacturing method enables a simple photoelectrode, which has excellent efficiency and on which various conductive polymers or dyes are can be applied, to be obtained, as well as a solar cell including the photoelectrode.

Description

Method for manufacturing photoelectrode and solar cell comprising photoelectrode manufactured thereby

The present invention relates to a photovoltaic cell manufacturing method and a photovoltaic cell including a photoelectrode manufactured by the method, which simplifies the manufacturing process and can be applied to a variety of conductive polymers or dyes, but also has excellent efficiency. It relates to a solar cell comprising a method and a photoelectrode produced thereby.

As one of the technical fields for solving the problems caused by environmental pollution and energy depletion, there is a growing interest in technology related to solar cells that can generate electricity without generating environmental pollutants.

Solar cells can be divided into inorganic solar cells made of inorganic materials such as silicon compound semiconductors and organic solar cells containing organic materials. The organic solar cells include dye-sensitized solar cells and organic molecular junction solar cells. Included.

Solar cells have been recognized as next-generation alternative energy sources due to high energy conversion efficiency and low manufacturing cost, and research on this is being actively conducted.

The prototype of the dye-sensitized solar cell is a photoelectric conversion element, namely solar cell [M. Graetzel, Nature, 353, 737 (1991), also called dye-sensitized solar cells or wet solar cells.

Dye-sensitized solar cells use the principle of forming excitons by irradiating light onto nanoparticle semiconductor oxide electrodes on which chemical dye molecules are chemically adsorbed, and double electrons being injected into the conduction band of the semiconductor oxide to generate current. .

The structure of a dye-sensitized solar cell generally makes a film of an electrode material (eg, a titanium oxide porous film) capable of adsorbing a dye on a conductive substrate (glass, plastic or metal), and ruthenium-based or organic material on the surface of the film. The dye is adsorbed, the counter electrode is made, and an electrolyte is injected between both electrodes to form one cell.

In this dye-sensitized solar cell, the electrolyte is used to control the flow of electrons between the working electrode and the counter electrode, and the flow of electrons is effectively controlled by using a liquid electrolyte containing iodine. Induction showed an efficiency of 12% (O'Regan, B. et al; Nature (1991), 353, p. 737, WO 91/16719).

However, when a solar cell containing a liquid electrolyte is exposed to hot sunlight and heat for a long time or is used for a long time, the liquid electrolyte expands due to heat, causing electrolyte leakage, which is pointed out as a cause of deterioration of the efficiency and stability of the dye-sensitized solar cell. Has been.

To overcome this problem, solid electrolytes using polymers have been developed (classified as semi-solid dye-sensitized solar cells), which have lower photoelectric conversion efficiencies than solar cells using liquid electrolytes. Due to the problem of poor stability, commercialization is being delayed.

Iodine is used as an electron transporting material in solid electrolytes using liquid electrolytes and polymers. Recently, corrosion of solar cell electrodes and toxicity of iodine caused by iodine have become a problem. Attention has been focused on the development of solid-state dye-sensitized solar cells that are not used as transfer materials.

As a hole transporting material (HTM) to replace iodine, inorganic materials and organic materials may be used. As inorganic materials, CuI and CuSCN may be used, and a study showing 4.7% efficiency has been reported. (1) J. Photochem. Photobiol. A 2004, 164, 183., (2) Adv. Mater. 2000, 12, 1263., (3) Langmuir 2003, 19, 3572.].

However, dye-sensitized solar cells using inorganic materials as hole transporting materials require complex synthesis processes such as high temperature treatment and electrodeposition, and thus are not only low in photoelectric conversion efficiency but also difficult to fabricate. It is not suitable for mass production, and economical.

Organic materials used as hole transporting materials can be divided into two types, organic monomolecules and organic polymers. Spiro-OMeTAD ((2,2-7.7-tetrakis (N, N'-) di paramethoxyphenyl-amine 9,9'-spirobifluorene) showed an efficiency of up to 5% and suggested a direction for the development of solid-state dye-sensitized solar cells without iodine [(1) Nature 1998, 395, 583. (2) Nano Lett. 2009, 9, 2487. (3) Nano Lett. 2007, 7, 3372. (4) J. Phys. Chem. C 2009, 113, 16816. (5) J. Am. Chem. Soc (6) Adv.Funct.Mate. 2009, 19, 1810. (7) Adv.Funct.Mate. 2009, 19, 2163. (8) Adv.Funct.Mate.2009, 19, 2431-436.

However, when the organic monomolecule is used as the hole transport material, the material may be easily changed by solar heat, which may greatly affect the efficiency of the solar cell. In addition, compared to the high price of Spiro-OMeTAD (235 $ / 10 mg, santa cruz biotechnology, Inc. as of July 25, 2010, santa cruz biotechnology, inc), the efficiency is limited in terms of both economic and efficiency characteristics.

In order to solve these problems of organic single molecules, researches using organic polymers as hole transport materials have been conducted. BACKGROUND OF THE INVENTION Conductive polymers have been studied for chemical and physical properties such as polymer type, polymerization method and conductivity, and organic polymers have been applied to various electric devices because they are relatively inexpensive and easy to handle.

The conductivity of the conductive polymer is different depending on the method of synthesis. The morphology of the conductive polymer, the degree of conjugation of the main chain, and the degree of warpage are determined by the polymerization method, and these properties affect the conductivity. to be. Therefore, in order to apply the conductive polymer as an efficient hole transport material of the dye-sensitized solar cell, it is important to apply a polymerization method of the conductive polymer to increase the electrical conductivity.

In order to increase the photoelectric conversion efficiency of the solar cell, it is important to penetrate the hole transport material well into the metal oxide thin film in addition to using a conductive polymer having high electrical conductivity. In other words, how well the hole transport material penetrates into the space between the metal oxide nanoparticles inside the thin film on which the dye is adsorbed is also an important factor to increase the photoelectric conversion efficiency of the solar cell.

In general, the conductive polymer is poorly soluble in most solvents, and the polymerized polymer is also very large, making it difficult to penetrate into the thin film. The solar cell using the polyaniline synthesized by electro-deposition by immersing the device in the organic solvent showed an efficiency of 1.15% [J. Phys. Chem. B 2004, 108, 18693.], The study using conjugated structure by optical coupling after penetrating the diacetylene monomer shows an efficiency of 0.8% [J. Chem. Mater. 2006, 18, 4215.]. In addition, solar cells using polyoctylthiophene showed an efficiency of about 1.3% [AdV. Mater. 2006, 18, 2579.], the use of these conductive polymers still showed low efficiency.

These methods are complex synthesis methods that go through a multi-step process, such as dipping the dye into a solution by dipping the device in a solution, and a method such as simple spin coating did not effectively penetrate the conductive polymer.

In order to effectively penetrate and synthesize the conductive polymer, a photoelectric polymerization method has been developed, which is a method of polymerization using a voltage generated from oxidation of a dye when the dye is exposed to light.

In this method, the conductive polymer monomer can be polymerized after penetrating the inside of the nanoparticle thin film. In this way, polypyrrole was initially used to show a low efficiency of 0.1% [Chem. Lett. 1997, 26,471.], And then 2.8% [J. J. using 3,4-ethylenedioxythiophene (EDOT) monomers to use highly conductive PEDOT (poly-3,4-ethylenedioxythiophene). AM. CHEM. SOC. 2008, 130, 1258], and recently, 6.1% [Adv. Mater. 2010, 22, E150-E155].

However, when the photoelectric polymerization method is used, the oxidation potential of the dye acts as a limiting factor.

Dyes have different oxidation voltages resulting from chemical structures and components, and various conductive polymer monomers have different oxidation voltages required for polymerization, and thus are very limited in the selection of dyes and conductive polymer monomers. In addition, using a wet process (wet process) is necessary after the polymerization washing process, the dye desorption and air exposure may be a problem. This complexity and problems in the process can be a major problem in mass production potential and battery stability.

In fact, in the above studies showing efficiency of 2.8% and 6.1%, bis-EDOT with two EDOT monomolecules attached rather than EDOT monomer was used. In order to induce the polymerization of EDOT, an oxidation voltage of 1.0V is required. But [Adv. Mater. 9 (1997) 795.], since the oxidation voltage generated by light by dye is only about 0.59V [Chem. Rev. 95 (1995) 49.] It is not possible to polymerize EDOT into monomers, and to make PEDOT, bis-EDOT with the same oxidation voltage of 0.4 V [Adv. Mater. 9 (1997) 795.] There was an additional problem that had to be synthesized and used.

This phenomenon is photoelectric polymerization method is very limited in the selection of dyes and conductive polymer monomers, it is a problem in the use of various dyes and conductive polymer monomers and the mass production process.

Therefore, for high efficiency and mass production of solar cells, not only the development of conductive polymers effective for use as hole transport materials but also various conductive polymers can be applied, the efficiency can be increased, and various dyes can be applied easily. There is an urgent need for the polymerization of conductive polymers and the development of solar cell manufacturing processes.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a photoelectrode which is simple in manufacturing method and is applicable to various conductive polymers or dyes and has excellent efficiency. Another object of the present invention is to provide a solar cell comprising a photoelectrode manufactured by the above manufacturing method.

In order to achieve the above object, a method of manufacturing a photoelectrode according to an embodiment of the present invention is a dye adsorption step of adsorbing a dye on the porous metal oxide thin film layer, the conductive metal monomer dissolved in a solvent, the dye is porous metal oxide A monomer penetrating step of penetrating the thin film layer, and a polymer synthesis step of synthesizing the conductive polymer monomer into a polymer by solid phase thermal polymerization.

The method may further include a solvent evaporation step of evaporating a solvent in which the conductive polymer monomer is dissolved between the monomer penetration step and the polymer synthesis step.

The polymer synthesis step may be made at 20 ℃ to 200 ℃.

The conductive polymer monomer may be any one selected from the group consisting of Formula 1, Formula 2, Formula 3, Formula 4, and combinations thereof.

[Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

In Chemical Formulas 1 to 4, each X is independently one selected from the group consisting of S, NR ₁₁ , Se, and Te, and R ₁₁ is any one selected from the group consisting of hydrogen, an alkyl group, and a heteroalkyl group. Y ₁ to Y ₈ are each independently selected from the group consisting of I, Br, Cl and F, and Z ₁ to Z ₆ are each independently CR ₁₂ R ₁₃ , NR ₁₄ , O and S in the group consisting of Any one selected, and R ₁₂ , R ₁₃ and R ₁₄ are each independently selected from the group consisting of hydrogen, an alkyl group and a heteroalkyl group, and R ₁ to R ₈ are each independently hydrogen, an alkyl group, a heteroalkyl group, Any one selected from the group consisting of an alkyl ester group, an alkyl carbonate group, a cycloalkyl group, an aryl group, a heteroaryl group, a heterocycloalkyl group, and a combination thereof.

In the monomer penetration step, the solvent of the conductive polymer monomer is dichloromethane (MC), chloroform, acetonitrile, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, dimethylvinylene carbonate, vinylethylene carbonate, methylethyl Carbonate (MEC), methylpropyl carbonate, methylbutyl carbonate, ethylpropyl carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, dibutyl carbonate, methanol, ethanol, butanol, propanol, isopropyl alcohol, Hexanol, heptanol, octanol, heptol, decaol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, pinacol, methyl propionate, methyl pivalate, butyl pivalate, hexyl pivalate, Octyl pivalate, dimethyl oxalate, ethyl methyl oxalate, diethyl oxalate, tetrahydrofuran, 2-methyltet Hydrofuran, 1,4-dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,2-dibutoxyethane, dimethylformamide, trimethyl phosphate, tributyl phosphate, trioctyl phosphate, di Vinyl sulfone, γ-butyrolactone, δ-valerolactone, α-angelicalactone, adiponitrile, 1,4-propane sultone, 1,4-butanediol dimethane sulfonate, propylene sulfite, glycol sulfate , Propylene sulphate, dipropargyl sulphite, methyl propargyl sulphite, ethyl propargyl sulphite, propylene sulphite, glycol sulphate, propylene sulphate, toluene, hexane, xylene, acetone and combinations thereof It may be any one selected from.

The conductive polymer monomer may include 0.0000001 to 10000 parts by weight based on 100 parts by weight of the solvent of the conductive polymer monomer in the monomer penetration step.

An additive injection step of injecting an additive including a nonvolatile ionic liquid and an ionic salt may be further included after the polymer synthesis step.

The non-volatile ionic liquid is 1-methyl-3-propylimidazolium iodine, 1-ethyl-3-methylimidazolium dicyanamid, 1-butyl-3-methyl-imidazolium chromide, 1-butyl 3-Methyl-imidazolium tetrafluoroborate, 1-butyl-3-methyl-imidazolium hexafluorophosphate, 1-butyl-3-methyl-imidazolium bis (trifluoromethanesulfonyl) De, 1-butyl-3-methyl-imidazolium trifluoromethanesulfonate, 1-butyl-3-methyl-imidazolium trifluoroacetate, 1-butyl-3-methyl-imidazolium dicyana Mead, 1-butyl-3-methyl-imidazolium thiocyanate, 1-butyl-3-methyl-imidazolium salt, 1-butyl-3-methyl-imidazolium tetrachloroperate, 4-tert- It may be any one selected from the group consisting of butylpyridine, saccharin and combinations thereof.

The ion salt may be any one selected from the group consisting of ammonium salt, sodium salt, lithium salt and combinations thereof.

The additive may further include 4-tert-butylpyridine.

The solar cell according to another embodiment of the present invention includes a photoelectrode manufactured by the method of manufacturing the photoelectrode.

Hereinafter, the present invention will be described in more detail.

All compounds or substituents herein may be substituted or unsubstituted unless otherwise specified.

Herein, substituted Iran hydrogen is a halogen atom, a hydroxy group, a carboxy group, a cyano group, a nitro group, an amino group, a thio group, a methyl thio group, an alkoxy group, a nitrile group, an aldehyde group, an epoxy group, an ether group, an ester group, an ester group , Carbonyl group, acetal group, ketone group, alkyl group, cycloalkyl group, heterocycloalkyl group, allyl group, benzyl group, aryl group, heteroaryl group, derivatives thereof, and any combination thereof. do.

Unless stated otherwise in the present specification, the prefix hetero means that one to three heteroatoms selected from the group consisting of -N-, -O-, -S-, and -P- replace a carbon atom. For example, a heteroalkyl group means that the said hetero atom substitutes 1-3 carbon atoms in the carbon atom of an alkyl group.

Unless otherwise specified in the present specification, an alkyl group is a linear or pulverized alkyl group having 1 to 30 carbon atoms, a heteroalkyl group is a heteroalkyl group having 1 to 30 carbon atoms, an alkylester group is an alkyl ester group having 1 to 20 carbon atoms, and an alkylcarbonate group having 1 to 30 carbon atoms 20 alkyl carbonate group, cycloalkyl group is a cycloalkyl group having 3 to 32 carbon atoms, aryl group is an aryl group having 6 to 30 carbon atoms, heteroaryl group is a heteroaryl group having 2 to 30 carbon atoms, heterocycloalkyl group is a heterocycloalkyl having 2 to 32 carbon atoms It means an alkyl group.

Unless stated otherwise in the specification, an alkylester group means a compound including an ester group and an alkyl group and a derivative thereof, and an alkylcarbonate group means a compound including a carbonate group and an alkyl group and a derivative thereof.

Unless otherwise specified in the present specification, a solar cell includes a dye-sensitized solar cell, an all-solid-type thin film cell, a thin film silicon solar cell, and a hybrid thereof, and the following description will be made based on the dye-sensitized solar cell, but is not limited thereto. no.

Referring to Figure 1, the manufacturing method of the photoelectrode of the present invention includes a dye adsorption step (S10), a monomer penetration step (S20), and a polymer synthesis step (S30).

The dye adsorption step (S10) includes the step of adsorbing the dye on the porous metal oxide thin film layer.

The porous metal oxide thin film layer may be formed on a conductive transparent electrode, and the conductive transparent electrode may be formed on a substrate.

The substrate is not limited as long as it is a substrate commonly used in solar cells, and includes a glass or plastic substrate.

The plastic substrate is polyethylene terephthalate (poly (ethylene terephthalate)), polyethylene naphthalate (poly (ethylene naphthalate)), polycarbonate (polycarbonate), polypropylene (polypropylene), polyimide (polyimide), triacetyl cellulose (triacetyl cellulose ), Polyethersulfone, and any one selected from the group consisting of copolymers thereof, and mixtures thereof.

The conductive transparent electrode is not limited as long as it is used as a conductive transparent electrode, but is indium tin oxide (ITO), fluorine tin oxide (FTO), ZnO-Ga ₂ O ₃ , ZnO-Al _It may be any one selected from the group consisting of ₂ O ₃ , tin oxide, antimony tin oxide (ATO), zinc oxide (zinc oxide) and combinations thereof.

The porous metal oxide thin film layer may be formed in a thickness of 3 um or more on the substrate, it may be formed of 3 um to 30 um. Preferably it can be formed in a thickness of 11um or more, it can be formed in 11um to 30um.

As the metal oxide thin film layer is made thicker, the amount of dye adsorption increases, which is advantageous for increasing the current density. When the porous metal oxide thin film layer is formed at the thickness, the conductive polymer can be sufficiently penetrated to synthesize a conductive polymer having a large surface area. Photoelectric conversion efficiency can be improved.

The porous metal oxide thin film layer may be formed using a nanoparticle sol, the particle diameter of the nanoparticles may be 1 nm to 300 nm, may be 10 nm to 60 nm. When the porous metal oxide thin film layer is formed using the nanoparticle sol, adhesion and durability between the transparent electrode and the metal oxide thin film layer may be improved.

The porous metal oxide thin film layer may be formed by applying a solution containing the nanoparticles to the substrate, the coating method is not particularly limited, screen printing method, spray coating method, coating method using a doctor blade, gravure coating Method, dip coating method, silk screen method, painting method, coating method using slit die, spin coating method, roll coating method, transfer coating method and the like can be used, and the doctor blade suitable for forming a porous film with a uniform thickness It can be applied using a method.

The metal oxide forming the porous metal oxide thin film layer formed on the transparent electrode may be represented by an oxide network of -MOM-, and M may be selected from the group consisting of Ti, Zn, Nb, W, and combinations thereof. It is not limited.

The dye includes a metal complex including any one selected from the group consisting of aluminum (Al), platinum (Pt), palladium (Pd), europium (Eu), lead (Pb), iridium (Ir), and ruthenium (Ru). May be used, an indoline dye may be used, or two or more of the dyes may be mixed.

The monomer penetration step (S20) includes a step of infiltrating the conductive polymer monomer dissolved in the solvent into the porous metal oxide thin film layer adsorbed by the dye.

As the solvent of the monomer used in the monomer penetration step (S20), a non-aqueous solvent may be used. Specifically, dichloromethane (MC), chloroform, acetonitrile, ethylene carbonate (EC), propylene carbonate (PC), butyl Ethylene carbonate, dimethylvinylene carbonate, vinylethylene carbonate, methylethyl carbonate (MEC), methylpropyl carbonate, methylbutyl carbonate, ethylpropyl carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, dibutyl Carbonate, methanol, ethanol, butanol, propanol, isopropyl alcohol, hexanol, heptanol, octanol, heptaol, decaol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, pinacol, methyl propionate, blood Methyl valine, butyl pivalate, hexyl pivalate, octyl pivalate, dimethyl oxalate, ethyl methyl oxalate, oxalic acid Ethyl, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,2-dibutoxyethane, dimethylformamide, trimethyl phosphate , Tributyl phosphate, trioctyl phosphate, divinyl sulfone, γ-butyrolactone, δ-valerolactone, α-angelicalactone, adiponitrile, 1,4-propane sultone, 1,4-butanediol dimethane Sulfonate, Propylene Sulfate, Glycol Sulfate, Propylene Sulfate, Dipropargyl Sulfite, Methyl Propargyl Sulfite, Ethyl Propargyl Sulfite, Propylene Sulfite, Glycol Sulfate, Propylene Sulfate, Toluene, Hexane, Xyl It may be any one selected from the group consisting of ene, acetone and combinations thereof, preferably alcohols and glycols.

When the non-aqueous solvent is used as the solvent of the monomer used in the monomer penetration step (S20), the conductive polymer monomer can effectively penetrate the metal oxide thin film.

The conductive polymer monomer may be a conductive polymer monomer capable of thermal polymerization, and specifically, may be any one selected from the group consisting of Formula 1, Formula 2, Formula 3, Formula 4, and combinations thereof.

[Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

In Chemical Formulas 1 to 4,

X is each independently selected from the group consisting of S, NR ₁₁ , Se and Te, wherein R ₁₁ is any one selected from the group consisting of hydrogen, an alkyl group and a heteroalkyl group, preferably R ₁₁ is hydrogen and It may be any one selected from the group consisting of alkyl groups having 1 to 5 carbon atoms.

Y ₁ to Y ₈ are each independently selected from the group consisting of I, Br, Cl and F, and Z ₁ to Z ₆ are each independently selected from CR ₁₂ R ₁₃ , NR ₁₄ , O and S Any one selected from.

R ₁₂ , R ₁₃ and R ₁₄ are each independently one selected from the group consisting of hydrogen, an alkyl group and a heteroalkyl group, and preferably may be any one selected from the group consisting of hydrogen and an alkyl group having 1 to 5 carbon atoms.

R ₁ to R ₈ are each independently selected from the group consisting of hydrogen, an alkyl group, a heteroalkyl group, an alkylester group, an alkylcarbonate group, a cycloalkyl group, an aryl group, a heteroaryl group, a heterocycloalkyl group, and a combination thereof .

In Chemical Formulas 1 to 4, preferably, X may be any one independently selected from the group consisting of S and Se, and each of R ₁ to R ₈ is independently hydrogen, an alkyl group having 1 to 10 carbon atoms, and 1 carbon atom. An alkyl ester group of 10 to 10, an alkyl carbonate group of 1 to 10 carbon atoms, a cycloalkyl group of 3 to 15 carbon atoms, an aryl group of 6 to 20 carbon atoms, a heteroaryl group of 2 to 20 carbon atoms, and a heterocycloalkyl group of 2 to 10 carbon atoms It may be any one selected from the group consisting of.

In the case of using the monomer of Chemical Formulas 1 to 4 as the conductive polymer monomer, the polymer can be polymerized into a conductive polymer in a solid state by thermal polymerization, has excellent electrical conductivity, and easily penetrates the monomer into the porous thin film.

Preferably, any one selected from the group consisting of EDOT, EDOS, and combinations thereof may be used as the conductive polymer monomer. In this case, mass synthesis of the conductive polymer in the photoelectrode is possible, but the synthesis is easy, and economical and high conductivity is possible, so that economic mass production of the solar cell is possible.

The conductive polymer monomer may be thermally polymerized, penetrated into the porous thin film in the form of monomer, and then polymerized in the form of Chemical Formulas 5 to 8 while undergoing thermal polymerization.

[Formula 5]

[Formula 6]

[Formula 7]

[Formula 8]

In Formulas 5 to 8, n is each independently a natural number between 1 and 1000000, and the definitions for X, Z ₁ to Z ₆ and R ₁ to R ₈ are the same as in Formulas 1 to 4 Omit the description.

The solution containing the conductive polymer monomer may include from 0.001 to 99.99% by weight of the monomer of the conductive polymer, it may comprise from 1 to 60% by weight.

When the concentration of the solution containing the conductive polymer monomer is less than 0.001% by weight, it is cumbersome and effective polymerization of the solution multiple times, and when the concentration of the solution exceeds 99.99% by weight, the monomer is effectively applied to the porous thin film. It can be difficult to penetrate.

The amount of the solution containing the conductive polymer monomer may be used in an appropriate amount in consideration of the kind of the monomer, the kind of the solution, the thickness of the photoelectrode layer, and the like.

The solvent of the solution containing the conductive polymer monomer may be removed before the polymer synthesis step of thermally polymerizing the conductive polymer monomer, and preferably may be removed by evaporation.

The polymer synthesis step (S30) includes a process of synthesizing the conductive polymer by solid-phase thermal polymerization.

The solid-phase thermal polymerization may be made at 20 ℃ to 200 ℃, it may be made at 50 ℃ to 100 ℃. When the thermal polymerization temperature is less than 20 ° C, the time required for the polymerization may be too long, and when the thermal polymerization temperature exceeds 200 ° C, polymerization may not occur or a conductive polymer having low conductivity may be polymerized. In order to maintain the temperature in the thermal polymerization, a warm air, a hot plate, an oven, or the like may be used, and if the temperature can be maintained, it is not limited, but it is preferable to use a chamber.

After the polymer synthesis step, an additive injection step (S40) for injecting an additive including a nonvolatile ionic liquid and an ionic salt may be further included.

The additive may be a mixture of a nonvolatile ionic liquid and an ionic salt, and the anion and ionic salt of the ionic liquid may be different in form and size.

The nonvolatile ionic liquid is preferably 1-methyl-3-propylimidazolium iodide, 1-ethyl-3-methylimidazolium dicyanamid (1-ethyl- 3-methylimidazolium dicyanamide), 1-Butyl-3-Methyl-Imidazolium Chloride, 1-butyl-3-methyl-imidazolium tetrafluoroborate (1- Butyl-3-Methyl-Imidazolium Tetrafluoroborate), 1-Butyl-3-Methyl-Imidazolium Hexafluorophosphate, 1-Butyl-3-methyl-imidazolium bis (Trifluoromethanesulfonyl) imide (1-Butyl-3-Methyl-Imidazolium bis (trifluoromethanesulfonyl) imide), 1-butyl-3-methyl-imidazolium trifluoromethanesulfonate (1-Butyl- 3-Methyl-Imidazolium trifluoromethanesulfonate), 1-Butyl-3-methyl-imidazolium trifluoroacetate, 1-Butyl-3-Methyl-Imidazolium trifluoroacetate, 1 -Butyl-3-methyl-imidazolium dicyanamide (1-Butyl-3-Methyl-Imidazolium Dicyanamide), 1-butyl-3-methyl-imidazolium thiocyanate (1-Butyl-3-Methyl-Imidazolium Tiocyanate), 1-butyl-3-methyl-imidazolium salt (1-Butyl-3-Methyl-Imidazolium salt), 1-butyl-3-methyl-imidazolium tetrachloroperate (1-Butyl-3- Methyl-Imidazolium Tetrachloroferrate), 4-tert-butylpyridine, 4-tert-butylpyridine, saccharin and any combination thereof may be used.

The ionic salt may be any one selected from the group consisting of ammonium salt, sodium salt, lithium salt and combinations thereof.

The ammonium salt is n-Bu₄NClO₄, n-Bu₄NPF₆, n-Bu₄NBF₄, n-Et₄NClO₄,And combinations thereof may be any one selected from the group consisting of, the sodium salt is NaPF₆, NaBF₄, NaClO₄And, and any combination thereof may be selected from the group consisting of, the lithium salt is LiClO₄, LiPF₆, LiBF₄, LiN (SO₂CF₃)₂, LiN (SO₂C₂F₅)₂, LiCF₃SO₃, LiC (SO₂CF₃)₃, LiPF₄(CF₃)₂, LiPF₃(C₂F₅)₃, LiPF₃(CF₃)₃, LiPF₃(iso-C₃F₇)₃, LiPF₅(iso-C₃F₇), (CF₂)₂(SO₂)₂NLi, (CF₂)₃(SO_{2) 2}It may be any one selected from the group consisting of Nli and combinations thereof, and hydrogen included in them may be substituted with a chain alkyl group.

The ion salt is preferably n-Bu4NClO ₄ , n-Bu4NPF _6, n-Bu _4N BF ₄ , NaClO ₄ , n-Et ₄ NClO ₄ , LiClO ₄ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiCF ₃ SO ₃ , LiC (SO ₂ CF ₃ ) ₃ , LiPF ₄ (CF ₃ ) ₂ , LiPF ₃ (C ₂ F ₅ ) _3, LiPF ₃ (CF ₃ ) ₃ , LiPF ₃ ( iso-C ₃ F ₇ ) ₃ , LiPF ₅ (iso-C ₃ F ₇ ) and combinations thereof, in which case the ion salt is further doped into the conductive polymer to The amount of may increase.

The ionic salt may be used in a molar of 1: 0.0000001 to 1: 200 in the nonvolatile ionic liquid.

In addition, the additive may further include 4-tert-butylpyridine. When the additive further comprises the 4-tert-butylpyridine can increase the photoelectric conversion efficiency.

Another embodiment of the present invention is a solar cell includes a photoelectrode manufactured by the manufacturing method. Specifically, the solar cell is manufactured by covering, pressing, and sealing the opposite electrode of the photoelectrode, but any method may be used without limitation as long as it is a method of manufacturing the solar cell.

The counter electrode may be indium tin oxide (ITO), fluorine tin oxide (FTO), ZnO-Ga ₂ O ₃ , ZnO-Al ₂ O ₃ , tin oxide, antimony tin oxide , ATO), zinc oxide, and a substrate having a conductive layer including one selected from the group consisting of a combination thereof, the substrate may include a transparent glass or plastic substrate.

The description of the substrate is the same as the description of the substrate used in the manufacture of the photoelectrode of the present invention, the description thereof is omitted.

The method of manufacturing the photoelectrode dissolves a conductive polymer monomer capable of solid-phase polymerization in an organic solvent and then inserts it into a space between nanoparticles in a metal oxide nanoparticle thin film in which dye is adsorbed, thereby effectively penetrating the conductive polymer monomer by heat. By simply polymerizing the conductive polymer, a conductive polymer having high conductivity is introduced into the hole transport material.

The solar cell including the photoelectrode according to another embodiment of the present invention may be a dye-sensitized solar cell, an all-solid-state thin film cell, a thin film silicon solar cell, and a hybrid thereof, and preferably, may be a dye-sensitized solar cell.

The solar cell including the photoelectrode manufactured by the above method simply improves the complex manufacturing method of the existing solar cell, and provides a method of manufacturing a solar cell having high stability and mass production. In addition, the dye-sensitized solar cell including the photoelectrode of the present invention enables to manufacture a solid-state dye-sensitized solar cell having high photoelectric conversion efficiency that does not include iodine as a hole transport material.

The manufacturing method of the photoelectrode of the present invention is easy to manufacture and can be applied to various conductive polymers or dyes, but also has excellent photoelectric conversion efficiency. In addition, the solar cell including the photoelectrode is easy to manufacture and can be applied to a variety of conductive polymers or dyes, but also has excellent photoelectric conversion efficiency.

1 is a flowchart illustrating a method of manufacturing a photoelectrode according to an embodiment of the present invention.

Fig. 2 is a FE-SEM photograph of a cross section of a titanium dioxide thin film layer formed in the preparation example of the photoelectrode.

3 is a FE-SEM photograph of the surface of the titanium dioxide thin film layer formed in the production example of the photoelectrode.

4 is a FE-SEM photograph of the cross section of the photoelectrode after polymerizing the conductive polymer.

5 is a FE-SEM photograph of the surface of the photoelectrode after polymerizing the conductive polymer.

FIG. 6 is a Niquist plot showing the resistance between the electrodes and the electrolytes of the solar cells A and B of the embodiment. In Figure 6,-▲-is a measure of the resistance of the battery A,-■-is a measure of the resistance of the battery B.

7 is a bode plot of solar cell A and solar cell B of the embodiment. -●-indicates a board plot of solar cell A, and-■-shows a board plot of solar cell B.

FIG. 8 is a graph showing the current densities of solar cell A (dotted line) and solar cell B (solid line) of the embodiment. FIG.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice 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.

광전극의 제조예Production Example of Photoelectrode

1. Formation of titanium dioxide thin film layer and adsorption of dye

TiO ₂ paste solution (TiO ₂ sol of 20-30 nm size) was drop cast on a 1.5 × 2.0 cm sized FTO glass substrate and applied by a doctor blade method. After drying in an oven at 50 ° C. for 30 minutes, the resultant was calcined at 450 ° C. to remove the polymer material and the residue contained in the paste, thereby improving anatase crystallinity, thereby preparing a titanium dioxide thin film having many pores and having a large surface area.

In order to adsorb the dye to the titanium dioxide thin film layer of the substrate, ruthenium-based dye N719 (Solaronix Solaronix Co., Ltd.) was prepared using a ethanol solvent, a 0.02% by weight dye-containing solution, the substrate containing the dye-containing solution Was impregnated at 50 ° C. for at least 3 hours to prepare a substrate on which the dye was adsorbed.

Referring to FIG. 2, which is an FE-SEM photograph (2,650 times) of the cross section of the substrate on which the dye is adsorbed, it was confirmed that the porous TiO ₂ layer having a thickness of about 11 μm was formed on the glass substrate. In addition, referring to FIG. 3, which is a FE-SEM photograph (200,000 times) of the surface of the substrate on which the dye is adsorbed, a titanium dioxide thin film having a porous structure having a large surface area having a size of about 20 to 30 nm of TiO ₂ inorganic particles is prepared. It could be confirmed.

2. Synthesis of hole transport material using conductive polymer monomer

The dye-adsorbed substrate was washed with alcohol to remove dye residue and dried in a vacuum oven at 50 ° C. The solution containing the monomer of the conductive polymer was dropped on the dried dye-adsorbed substrate several times.

The monomer of the conductive polymer represented by the following Chemical Formula 1-1 was dissolved in an alcohol solvent to prepare a solution of 1% by weight and 3% by weight for the drop casting.

[Compound 1-1]

After evaporating the alcohol solvent and wrapping it in aluminum foil, it was placed in a chamber and sealed, put in an oven having an oven temperature of 60 ° C., and synthesized for 24 hours to prepare a photoelectrode.

Referring to FIG. 4, which is a FE-SEM photograph (150,000 times) of the photoelectrode cross-section after polymerization of the conductive polymer, and FIG. 5, which is a FE-SEM photograph (100,000 times) of the photoelectrode surface after polymerization of the conductive polymer, TiO _{Since the} conductive polymer is filled between the porous thin film layers having ₂ , it was confirmed that the monomer which penetrated into the TiO ₂ pores into the liquid phase was well penetrated into the pores even after the polymerization.

태양전지의 제조예Production Example of Solar Cell

3. Electrolytic Casting and Manufacturing Step of Solar Cell-Solar Cell A and Solar Cell B

Cast an ionic liquid, MPII (1-methyl-3-propylimidazolium iodide), an electrolyte to the photoelectrode, assemble a conductive glass coated with platinum (Pt) as a counter electrode, and pressurize the conductive polymer layer to form two electrodes. It was strongly attached to the surface of, and sealed with an epoxy bond (sealing) to manufacture a solar cell A.

In addition, an ionic liquid, MPII (1-methyl-3-propylimidazolium iodide), and LiTFSI and 4-tert-butylpyridine, which are electrolytes, are cast on the photoelectrode and platinum (Pt) is used as a counter electrode. ) Was coated with a conductive glass, pressurized to strongly adhere the conductive polymer layer to the surfaces of the two electrodes, and sealing using an epoxy bond to prepare a solar cell B.

태양전지의 물성평가Property evaluation of solar cell

1. Conductivity and resistance measurement

In the Nyquist plot, the resistance between each electrode and the electrolyte of the solar cell A and the solar cell B was confirmed (see FIG. 6). In Fig. 6, the value representing the resistance between the counter electrode and the electrolyte and the value representing the resistance between the TiO ₂ particles and the electrolyte were significantly smaller. In addition, in the case of solar cell B in which lithium salt (LiTFSI) was added to the ionic liquid, the resistance of each was further reduced.

In FIG. 7, referring to the board plots of solar cell A and solar cell B of the embodiment, it can be seen that the life time of the electrons generated at the position of the intermediate frequency of the bode plot is added rather than solar cell A. In the case of solar cell B incorporating furnace salt, the life time of the electron was longer.

2. Efficiency Analysis of Solar Cell

The photoelectric conversion efficiency is 0.8% in the efficiency analysis of the dye-sensitized solar cell using the conventional titanium dioxide thin film as the photoelectrode, the conductive polymer as the hole transport material, and the addition of iodine using the ruthenium-based dye. (1) J. Phys. Chem. B 2004, 108, 18693. [2] J. Chem. Mater. 2006, 18, 4215. [3] AdV. Mater. 2006, 18, 2579. [4] Chem. Lett. 1997, 26,471. [5] J. AM. CHEM. SOC. 2008, 130, 1258).

However, referring to FIG. 8 and Table 1 below, it can be seen that the efficiency of the solar cell A and the solar cell B of the embodiment is about 4.3% and about 5.4%, which are superior to those in the above case. Adv. Mater. 2011,23,1641-1646]

Table 1

	Pin (mW / cm ² )	Voc (V)	Jsc (mA / cm ² )	Voc * Jsc (mW / cm ² )	Vmax * Jmax (mW / cm ² )	FF	efficiency(%)
Solar cell B	100	0.642	14.2	9.11640	5.4456250	0.5973438	5.446
Solar cell A	100	0.595	11.9	7.08050	4.2868750	0.6054481	4.287

The high efficiency of Table 1 is difficult to infiltrate the monomer into the TiO ₂ pores of the thin film in the previous studies, the monomer was more difficult to penetrate when the thickness of the thin film, but in the case of the present invention can be dissolved in an organic solvent effectively It seems to solve the problem of monomer penetration and limitation of the thickness of the TiO ₂ layer by thermally polymerizing the hole transport material using a monomer that can penetrate into the pores of the thin film to form a solid phase. Due to the problem of penetration, even if the thickness of the existing TiO ₂ photoelectrode layer of about 6 um or more is 11 um or more, the monomer can be sufficiently penetrated into the thin film, and the dye can be adsorbed at the increased thickness. ) Is one of the reasons for the improvement of the efficiency of the solar cell of the present invention. In addition, the addition of more ionic salts reduced the resistance between the structures and showed higher efficiency.

3. Improvement of solar cell efficiency by introducing interfacial layer

In order to confirm that the photoelectrode according to an embodiment of the present invention is effectively applied and operated when introducing another technology for improving the efficiency of the solar cell, a lot of light is introduced by introducing an interface layer that can transmit a lot of light To reach.

Since most FTO substrates are cloudy due to the nature of the material, and have low transmittance, a thin TiO layer is coated and then TiO2 photoelectrode layer is coated thereon to improve the bonding and interfacial properties of the substrate and the TiO 2 layer. . At this time, the transmittance decreases, so that a lot of light cannot effectively reach the photoelectrode layer, so high efficiency is difficult to expect.

Therefore, in order to improve the efficiency of solar cells by improving the transmittance through improving the interfacial properties, research on this interfacial layer has recently been carried out, among which the mesoporous interfacial layer manufacturing technology developed by the research team ([1] Korean application) No. 2010-0140059, [2] J. Mater. Chem. 2011, 21, 1772-1779) was introduced into the solar cell B prepared above to prepare a solar cell C. The efficiency of the manufactured solar cell C was measured in the same manner as in the solar cell B of Table 1, and the results are shown in Table 2 below.

TABLE 2

	Pin (mW / cm2)	Voc (V)	Jsc (mA / cm2)	Voc * Jsc (mW / cm2)	Vmax * Jmax (mW / cm2)	FF	efficiency(%)
Solar cell C	100	0.643	18.6	11.95980	6.7723408	0.5662587	6.772

Referring to Table 2, the solar cell C showed a high efficiency up to 6.77% and improved Jsc under the same solar cell evaluation conditions (Adv. Func. Mater. 2011, online published, DOI: 10.1002 / adfm.201101520) . It is believed that the efficiency is increased because a large amount of light reaches the photoelectrode through the electrode having higher transmittance.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims

A dye adsorption step of adsorbing a dye on the porous metal oxide thin film layer,

Monomer penetration step of penetrating the conductive polymer monomer dissolved in the solvent to the porous metal oxide thin film layer adsorbed, and

Polymer synthesis step of synthesizing the conductive polymer monomer into a polymer by solid phase thermal polymerization

Method of manufacturing a photoelectrode comprising a.
The method of claim 1,

And a solvent evaporation step of evaporating the solvent in which the conductive polymer monomer is dissolved between the monomer penetration step and the polymer synthesis step.
The method of claim 1,

The polymer synthesis step is a method of manufacturing a photoelectrode made at 20 ℃ to 200 ℃.
The method of claim 1,

The conductive polymer monomer is a method of producing a photoelectrode of any one selected from the group consisting of the following formula (1), (2), (3), (4) and combinations thereof.

[Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

In Chemical Formulas 1 to 4,

X is each independently selected from the group consisting of S, NR 11 , Se and Te, wherein R 11 is any one selected from the group consisting of hydrogen, an alkyl group and a heteroalkyl group,

Y 1 to Y 8 are each independently selected from the group consisting of I, Br, Cl, and F,

Z 1 to Z 6 are each independently selected from the group consisting of CR 12 R 13 , NR 14 , O and S, and R 12 , R 13 and R 14 are each independently hydrogen, an alkyl group and a heteroalkyl group. Any one selected from the group consisting of,

R 1 to R 8 are each independently selected from the group consisting of hydrogen, an alkyl group, a heteroalkyl group, an alkylester group, an alkylcarbonate group, a cycloalkyl group, an aryl group, a heteroaryl group, a heterocycloalkyl group, and a combination thereof .
The method of claim 1,

In the monomer penetration step, the solvent of the conductive polymer monomer is dichloromethane (MC), chloroform, acetonitrile, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, dimethylvinylene carbonate, vinylethylene carbonate, methylethyl Carbonate (MEC), methylpropyl carbonate, methylbutyl carbonate, ethylpropyl carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, dibutyl carbonate, methanol, ethanol, butanol, propanol, isopropyl alcohol, Hexanol, heptanol, octanol, heptol, decaol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, pinacol, methyl propionate, methyl pivalate, butyl pivalate, hexyl pivalate, Octyl pivalate, dimethyl oxalate, ethyl methyl oxalate, diethyl oxalate, tetrahydrofuran, 2-methyltet Hydrofuran, 1,4-dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,2-dibutoxyethane, dimethylformamide, trimethyl phosphate, tributyl phosphate, trioctyl phosphate, di Vinyl sulfone, γ-butyrolactone, δ-valerolactone, α-angelicalactone, adiponitrile, 1,4-propane sultone, 1,4-butanediol dimethane sulfonate, propylene sulfite, glycol sulfate , Propylene sulphate, dipropargyl sulphite, methyl propargyl sulphite, ethyl propargyl sulphite, propylene sulphite, glycol sulphate, propylene sulphate, toluene, hexane, xylene, acetone and combinations thereof Method for producing a photoelectrode which is any one selected from.
The method of claim 1,

The conductive polymer monomer is a method for producing a photoelectrode comprising 0.0000001 to 10000 parts by weight based on 100 parts by weight of the solvent of the conductive polymer monomer in the monomer penetration step.
The method of claim 1,

The method of manufacturing a photoelectrode further comprising an additive injection step of injecting an additive comprising a non-volatile ionic liquid and an ionic salt electrolyte after the polymer synthesis step.
The method of claim 7, wherein

The non-volatile ionic liquid is 1-methyl-3-propylimidazolium iodine, 1-ethyl-3-methylimidazolium dicyanamid, 1-butyl-3-methyl-imidazolium chromide, 1-butyl 3-Methyl-imidazolium tetrafluoroborate, 1-butyl-3-methyl-imidazolium hexafluorophosphate, 1-butyl-3-methyl-imidazolium bis (trifluoromethanesulfonyl) De, 1-butyl-3-methyl-imidazolium trifluoromethanesulfonate, 1-butyl-3-methyl-imidazolium trifluoroacetate, 1-butyl-3-methyl-imidazolium dicyana Mead, 1-butyl-3-methyl-imidazolium thiocyanate, 1-butyl-3-methyl-imidazolium salt, 1-butyl-3-methyl-imidazolium tetrachloroperate, 4-tert- Butyl pyridine, saccharin and any one selected from the group consisting of a combination thereof.
The method of claim 7, wherein

Ammonium salt, sodium salt, lithium salt, and any one selected from the group consisting of a combination thereof.
The method of claim 7, wherein

The additive is a method of manufacturing a photoelectrode further comprises 4-tert-butylpyridine.
A solar cell comprising a photoelectrode prepared according to any one of claims 1 to 10.