KR102001773B1 - Conductive polymer solution controlled particle size and preparing method the same - Google Patents

Abstract

According to the present invention, a conductive polymer solution homogeneous-treats conductive polymer solutions under a high-pressure of 1,000 bar or more and manufactures a homogeneous solution containing conductive polymer particles having a particle diameter distribution of 10-200 nm, thereby improving dispersibility and permeability. According to the present invention, the conductive polymer solution additionally comprises a step of mixing dopants in a solution after the homogeneous treatment, thereby doping in manufacture of conductive polymer solutions to simplify processes and improve electrical conductivity, compared with existing methods which perform an additional doping process by soaking a conductive polymer film in a solution containing dopants after manufacturing the same. In addition, the conductive polymer solution further comprises a step of filtering by using a filtration film after manufacturing the solution to filter unnecessary materials such as ions, unreacted monomers, unreacted oligomers and polymer electrolytes in excessive amounts which are not removed after the reaction in the conductive polymer solution, thereby improving the electrical conductivity of a film manufactured by using the conductive polymers. Moreover, the present invention filters only particles having a desirable particle diameter by controlling a porous size of the filtration film to manufacture a homogeneous conductive polymer solution.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive polymer solution having controlled particle diameters and a method of manufacturing the conductive polymer solution.

The present invention relates to a conductive polymer solution whose particle diameter is controlled by homogeneous treatment and a method for producing the same.

BACKGROUND OF THE INVENTION [0002] As various home appliances and communication devices including computers are digitized and rapidly improved in performance, development of transparent conductive materials for use as electrodes of electronic devices is required. For example, in order to realize a portable display, the electrode material for a display must have transparency and low resistance as well as high flexibility to cope with mechanical impact, and even if the device is overheated and exposed to a high temperature, Should not be large.

ITO (indium-tin oxide) is the most commonly used transparent electrode material for displays. However, when the transparent electrode is formed of ITO, not only is an excessive cost consumed, but also it is difficult to realize a large area. In particular, when the ITO is coated on a large area, the change of the sheet resistance is large, and the luminance and luminous efficiency of the display are reduced. In addition, indium, which is the main raw material of ITO, is a limited minerals and is rapidly depleting as the display market expands.

In order to overcome the disadvantages of ITO, studies are being conducted to form a transparent electrode using a conductive polymer having excellent flexibility and a simple coating process.

In order to form the transparent electrode, it is preferable to use a conductive polymer having high conductivity. As a method of synthesizing the conductive polymer having the high conductivity, the conductive polymer monomer and the ionic polymer electrolyte are mixed to cause polymerization of the conductive polymer monomer. At this time, the size of the particles present in the mixture of the conductive polymer monomer and the ionic polymer electrolyte is made constant. However, because of the ionic electrolyte, existing particles are clumped together and become larger than the size of the originally formed particles, and a process of physically removing these entangled particles from each other after synthesis is essential. When such a process is carried out, a dispersion having a very uniform particle distribution is produced. However, when the particles are pulverized to a too small size, it is difficult to assemble the particles such as dense particles during coating, resulting in poor coating property and troublesome to use additives And it may not be easy to produce a thick film and a highly conductive film at a specific viscosity. Therefore, particle size control during pulverization of the particles can be a very important technique.

Korean Patent Publication No. 2016-0028630

The present invention relates to a conductive polymer solution having a controlled particle diameter and a method for producing the conductive polymer solution. The conductive polymer solution is homogenized to control the particle diameter of the conductive polymer, thereby providing a nanometer-sized homogeneous conductive polymer solution and a method for producing the conductive polymer solution.

In order to solve the above problems,

The present invention, in one embodiment,

There is provided a conductive polymer solution containing conductive polymer particles having a particle diameter within a range of 10 to 200 nm.

In addition, the present invention, in one embodiment,

And homogenizing the conductive polymer solution under a high-pressure condition of 1000 bar or more.

The conductive polymer solution according to the present invention can improve the dispersibility by preparing a homogeneous solution containing the conductive polymer particles having a particle size distribution within the range of 10 to 200 nm by homogenizing the conductive polymer solution under high pressure of 1000 bar or more So that the transmittance can be improved.

The conductive polymer solution according to the present invention may further include a step of mixing the dopant in the solution after the homogenization treatment so that the conductive polymer solution is prepared by adding the dopant to the solution containing the dopant after the preparation of the conductive polymer film, The doping can be performed, the process can be simplified, and the electric conductivity can be improved.

In addition, the conductive polymer solution according to the present invention may further include a step of filtration using a filtration membrane after the production, so that the ions, unreacted monomers, unreacted oligomers and excess polyelectrolytes, which are not removed after the reaction in the conductive polymer solution Unnecessary materials can be filtered to improve the electrical conductivity of the film produced using the conductive polymer and to control the pore size of the filtration membrane during filtration to filter only particles having a desired particle size to produce a homogeneous conductive polymer solution .

When the film is produced using the conductive polymer solution according to the present invention, the average light transmittance in the visible light region is 79% or more and the haze is 1 or less under the sheet resistance of 80? / Sq, and the CIE color coordinate standard b * The conductive polymer film having a thickness in the range of 3 to -2 can be produced.

1 is a TEM photograph of a conductive polymer solution according to an embodiment.
FIG. 2 shows the electrical conductivity measurement results of the films prepared using the conductive polymer solution according to the examples and the comparative examples.
FIG. 3 shows the results of measurement of light transmittance of a film prepared using the conductive polymer solution according to Examples and Comparative Examples.
FIG. 4 shows the haze measurement results of the films prepared using the conductive polymer solution according to Examples and Comparative Examples.
FIG. 5 shows the results of measurement of b * values of the films prepared using the conductive polymer solution according to the examples and the comparative examples.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In the present invention, the terms "comprising" or "having ", and the like, specify that the presence of a feature, a number, a step, an operation, an element, a component, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Hereinafter, the present invention will be described in detail.

ITO (indium-tin oxide) is the most commonly used transparent electrode material for displays. However, when the transparent electrode is formed of ITO, it is not only an excessive cost but also a difficulty in realizing a large area. In order to overcome the drawbacks of ITO, it is necessary to use a conductive polymer having excellent flexibility and a simple coating process Studies for forming a transparent electrode are underway.

In order to form the transparent electrode, it is preferable to use a conductive polymer having high conductivity. As a method of synthesizing the conductive polymer having the high conductivity, the conductive polymer monomer and the ionic polymer electrolyte are mixed to cause polymerization of the conductive polymer monomer. At this time, the size of the particles present in the mixture of the conductive polymer monomer and the ionic polymer electrolyte is made constant. However, because of the ionic electrolyte, existing particles tend to clump together and become larger than the size of the originally formed particles, so that a process of physically removing these entangled particles from each other after synthesis is essential. When such a process is carried out, a dispersion having a very uniform particle distribution is produced. However, when the particles are pulverized to a too small size, it is difficult to assemble such as dense particles between the particles during coating, And it may not be easy to produce a thick film and a highly conductive film at a specific viscosity.

Therefore, it is very important to control the particle size when pulverizing the particles.

Accordingly, the present invention can provide a conductive polymer solution containing conductive polymer particles having a particle diameter in the range of 10 to 200 nm.

Specifically, the conductive polymer solution according to the present invention can improve dispersibility by producing a homogeneous solution containing conductive polymer particles having a particle size of nanometer size within a range of 10 to 200 nm, thereby improving the permeability And it is possible to prevent a phenomenon of scattering caused by voids between large-size particles.

The conductive polymer particles having a particle diameter within the range of 10 to 200 nm may be 90 wt% or more of the total conductive polymer particles. For example, the particle size may be in the range of 10 to 150 nm, 10 to 100 nm, 10 to 80 nm, or 10 to 50 nm. The conductive polymer particles having a particle diameter in the range of 10 to 200 nm in the conductive polymer solution may be 90 to 100% by weight, 95 to 100% by weight, or 98 to 100% by weight of the total conductive polymer particles. In the conductive polymer solution, particles having a particle diameter of less than 10 nm and a particle diameter of more than 200 nm may be present in an amount of 10 parts by weight or less, 5 parts by weight or less, or 3 parts by weight or less. This may mean that the problem due to the size of the particulate component in the conventional solution can be reduced.

The half width of the particle size distribution diagram may be 30 to 60 nm. For example, the hemispheric width may be between 35 and 55 nm or between 40 and 50 nm. The particle size of the particles in the conductive polymer solution is uniform, and the dispersibility can be improved, thereby improving the permeability.

In the present invention, the half-width refers to the difference between two values of the point at half the maximum value in the particle size distribution diagram.

The concentration of the conductive polymer may be 1 to 5 wt%. For example, the concentration of the conductive polymer particles may be 1 to 4 wt%, 1 to 3 wt%, 1 to 2 wt%, 2 to 5 wt%, 3 to 5 wt%, or 4 to 5 wt% .

In addition, the present invention can provide a method for producing a conductive polymer solution including homogenizing a conductive polymer solution under a high-pressure condition of 1000 bar or more.

For example, the homogenizing step may be performed at a high pressure of 1000 to 1800 bar, 1200 to 1800 bar, 1500 to 1800 bar, or 1600 to 1800 bar.

The conventional method of homogenizing the conductive polymer solution is homogenized at a micrometer-sized particle diameter under a medium-low pressure condition, while the conductive polymer solution of the present invention is homogenized under high pressure or ultra-high pressure conditions to have a nanometer size, specifically 10 to 200 nm It is possible to produce a homogeneous conductive polymer solution having a particle diameter distribution in the range of from about 10 <

By this homogenization, it is possible that at least 90% by weight of the total particles in the conductive polymer solution have a particle diameter within the range of 10 to 200 nm. For example, at least 90% by weight of the total particles in the conductive polymer solution may have a particle diameter in the range of 10 to 150 nm, 10 to 100 nm, 10 to 80 nm, or 10 to 50 nm. For example, the particles having a particle diameter within the range of 10 to 200 nm in the conductive polymer solution may be 90 to 100% by weight, 95 to 100% by weight, or 98 to 100% by weight of the total particles in the conductive polymer solution. In the conductive polymer solution, particles having a particle diameter of less than 10 nm and a particle diameter of more than 200 nm may be present in an amount of 10 parts by weight or less, 5 parts by weight or less, or 3 parts by weight or less. This may mean that the problem due to the size of the particulate component in the conventional solution can be reduced.

The half width of the particle size distribution diagram may be 30 to 60 nm. For example, the hemispheric width may be between 35 and 55 nm or between 40 and 50 nm. The particle size of the particles in the conductive polymer solution is uniform, and the dispersibility can be improved, thereby improving the permeability.

The homogenization step may be repeated at least twice. The homogenization can be performed by a homogenizer and can be repeated two or more times to produce a solution having a more uniform particle size.

And then cooling to 10-20 < 0 > C after the homogenization step. During the homogenization, high temperature heat may be generated, which may lead to aggregation of dispersed particles in the solution, so that the step of cooling to 10 to 20 캜 after the homogenization step may be further included. Therefore, the solution after the cooling step can improve the solution stability.

And mixing the dopant after the homogenization step.

Further, it may further include a step of filtering using a filtration membrane after the homogenization step.

As a method for improving the electrical conductivity of a transparent electrode formed of a conventional conductive polymer, there has been studied a method of forming a film using a conductive polymer solution and further dipping it in a solution containing a dopant, Which is complicated and requires a long process time. Alternatively, the doping rate of the conductive polymer can be increased by adding a dopant to the conductive polymer solution. However, when the ion dopant is added to the PEDOT: PSS solution containing a large amount of the ionic substance, the viscosity of the solution gradually increases, There is a disadvantage in that a phenomenon of falling and gel hardening occurs, and thus existing methods are difficult to be used industrially.

However, since the conductive polymer solution according to the present invention further includes a step of mixing the dopant in the solution after the homogenization treatment, the conductive polymer solution may be added to the solution containing the dopant after the preparation of the conductive polymer film, It can be doped at the time of manufacture, the process can be simplified, and the electric conductivity can be improved.

In addition, the conductive polymer solution according to the present invention may further include a step of filtration using a filtration membrane after the production, so that the ions, unreacted monomers, unreacted oligomers and excess polyelectrolytes, which are not removed after the reaction in the conductive polymer solution Unnecessary materials can be filtered to improve the electrical conductivity of the film produced using the conductive polymer and to control the pore size of the filtration membrane during filtration to filter only particles having a desired particle size to produce a homogeneous conductive polymer solution .

The dopant is not particularly limited, but may include an organic compound containing oxygen and nitrogen. For example, the dopant may include at least one selected from the group consisting of an ammonium salt electrolyte, a sodium salt electrolyte, a lithium salt electrolyte, an iron salt electrolyte, a sulfonic acid compound, and sulfuric acid.

The ammonium salt electrolyte may include at least one of tetra-n-Bu ₄ NClO ₄ , n-Bu ₄ NPF ₆ , n-Bu ₄ NBF ₄ and n-Et ₄ NClO ₄ .

The sodium salt electrolyte may include, for example, at least one of NaPF ₆ , NaBF _4, and NaClO ₄ .

The lithium salt electrolyte, for _{example, LiClO 4, LiPF 6, LiBF} 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 a lithium salt electrolyte having a cyclic alkylene group.

For example, the lithium salt having a cyclic alkylene group may include (CF ₂ ) ₂ (SO ₂ ) ₂ NLi and (CF ₂ ) ₃ (SO ₂ ) ₂ NLi.

The iron salt electrolyte may include, for example, iron (III) oxide p-toluenesulfonic acid.

The sulfonic acid compound is, for example, an alkanesulfonic acid having 1 to 20 carbon atoms, a perfluoroalkanesulfonic acid having 1 to 20 carbon atoms, an alkylhexylcarboxylic acid having 1 to 20 carbon atoms, a purple having 1 to 20 carbon atoms An aromatic sulfonic acid substituted or unsubstituted by an alkyl group having 1 to 20 carbon atoms, and a cycloalkanesulfonic acid (e.g., camphorsulfonic acid).

Specifically, the sulfonic acid compound may be selected from the group consisting of methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, butanesulfonic acid, dodecanesulfonic acid, octadecanesulfonic acid, nonadecanesulfonic acid, trifluoromethanesulfonic acid, perfluorobutane Sulfonic acid, perfluorooctanesulfonic acid, ethylhexylcarboxylic acid, benzenesulfonic acid, o-toluenesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, P-toluenesulfonic acid and p-toluenesulfonic acid.

The dopant may be discontinued or a mixture of two or more dopants may be used.

For example, the dopant may be either a sulfuric acid or a sulfonic acid compound, or two or more thereof.

The dopant may be dissolved and mixed in a solvent.

The solvent used in mixing the dopant is not particularly limited as long as it can dissolve the dopant and can be mixed with water.

For example, the solvent may be at least one selected from the group consisting of water, tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), acetonitrile, and an alcohol-based solvent.

Wherein the step of filtering the conductive polymer solution using the filtration membrane comprises:

After mixing the conductive polymer solution and the dopant, the unreacted dopant can be removed by filtration. For example, in the course of mixing the conductive polymer solution and the dopant, the dopant may be doped in the conductive polymer. In this case, when the unreacted dopant that is not doped in the conductive polymer is excessive, The electric conductivity may be lowered. Therefore, the unreacted dopant can be removed by filtration to prevent a decrease in electric conductivity.

The order and method of mixing the dopant solution are not particularly limited. For example, the step of mixing the conductive polymer solution and the dopant and the step of filtering the solution using the filtration membrane may be performed at the same time.

The conductive polymer may include a repeating unit represented by the following Formula 1:

[Chemical Formula 1]

In Formula 1,

X and Y each independently represent O, S, Si or N; R ₁ and R ₂ each independently represent hydrogen, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxy group having 3 to 20 carbon atoms An aryl group or a heteroaryl group having 2 to 20 carbon atoms, and n is an integer of 2 to 2000, and optionally, R ₁ and R ₂ are bonded to each other to form a fused ring structure.

At this time, the alkyl group may mean a functional group derived from a linear or branched saturated hydrocarbon.

Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a 1,1-dimethylpropyl group, Ethylpropyl group, 2-ethylpropyl group, n-hexyl group, 1-methyl-2-ethylpropyl group, 1-ethyl- Methylbutyl group, 1,1-dimethylbutyl group, 1,2-dimethylbutyl group, 2,2-dimethylbutyl group, Dimethylbutyl group, 2,3-dimethylbutyl group, 2-ethylbutyl group, 2-methylpentyl group, 3-methylpentyl group and the like.

In addition, the aryl group may mean a monovalent substituent derived from an aromatic hydrocarbon.

Specific examples of the aryl group include a phenyl group, a naphthyl group, an anthracenyl group, a phenanthryl group, a naphthacenyl group, a pyrenyl group, A tolyl group, a biphenylyl group, a terphenyl group, a chrycenyl group, a spirobifluorenyl group, a fluoranthenyl group, a fluorine group, A perfluoroalkyl group, a fluorenyl group, a perylenyl group, an indenyl group, an azulenyl group, a heptalenyl group, a phenalenyl group, a phenanthrenyl group phenanthrenyl group).

Further, the heteroaryl group represents an aromatic heterocycle or a heterocyclic group derived from a monocyclic or condensed ring. The heteroaryl group may include at least one of nitrogen (N), sulfur (S), oxygen (O), phosphorus (P), selenium (Se), and silicon (Si) as a heteroatom.

Specific examples of the heteroaryl group include pyrrolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazolyl, tetrazolyl, benzotriazolyl, pyrazolyl, imidazolyl, An imidazolyl group, an imidazolyl group, a thiazolyl group, an isothiazolyl group, a benzothiazolyl group, a benzothiadiazolyl group, a phenothiazyl group, an isoxazolyl group, a furazanyl group, a phenoxazinyl group, , A benzooxazolyl group, an oxadiazolyl group, a pyrazoloxazolyl group, an imidazothiazolyl group, a thienopuranyl group, a furopyrrolyl group, and a pyridoxazinyl group.

As an example, the conductive polymer may be represented by the following formula (1): K (K is an arbitrary integer between 2 and 2000) repeating structure, X, Y, R ₁ and R < ₂ > may be different from each other. For example, the conductive polymer having the structure of Formula 1 may include at least one selected from the structures represented by Chemical Formulas 2 to 4 below.

(2)

(3)

[Chemical Formula 4]

In the above Chemical Formulas 2 to 4,

and n is an integer of 2 to 2000.

Specifically, the conductive polymer may be at least one selected from the group consisting of poly (3,4-ethylenedioxythiophene): polystyrene sulfonic acid, polypyrrole: polystyrene sulfonic acid, and polythiophene: polystyrene sulfonic acid.

The conductive polymer may be PEDOT: PSS.

The conductive polymer solution may be prepared by homogenizing the conductive polymer solution under a high pressure of 1000 bar or more to prepare a homogeneous solution having a particle size distribution of nanometer size to improve dispersibility and permeability, The process can be simplified and the electrical conductivity can be improved. By filtration using a filtration membrane, impurities can be filtered and only particles having a desired particle diameter can be filtered to produce a more homogeneous conductive polymer solution.

When the film is produced using the conductive polymer solution according to the present invention, the average light transmittance in the visible light region is 79% or more and the haze is 1 or less under the sheet resistance of 80? / Sq, and the CIE color coordinate standard b * The conductive polymer film having a thickness in the range of 3 to -2 can be produced.

When the conductive polymer solution is used, the average light transmittance in the visible light region is 79% or more and the haze is 1 or less under the sheet resistance of 80? / Sq as the dispersibility of the conductive polymer solution is improved. A conductive polymer film having a CIE color coordinate standard b * in the range of -3 to -2 can be produced. For example, the average light transmittance in the visible light region may be 79 to 82%, 80 to 82%, or 81 to 82%, and the haze may be 1 or less, 0.8 or less, or 0.5 ≪ / RTI >

Hereinafter, the present invention will be described in more detail with reference to the following Examples. However, the scope of the present invention is not limited by the following Examples.

Example

12.53 g of polystyrene sulfonic acid (PSS, Mw 75,000) was dissolved in 1400 g of distilled water and 0.2 g of iron sulfate as a catalyst was added to the reaction vessel and stirred until it was dissolved. When all of the iron sulfate was dissolved, the temperature of the solution was lowered to 13 캜, and 30 g of an aqueous solution containing 11.9 g of sodium persulfate as a dopant was mixed. Then, 5.014 g of 3,4-ethylenedioxythiophene (EDOT) monomer was added and the polymerization reaction was carried out for 35 hours. Conductive polymer solution was prepared by removing unnecessary ions by adding 500 mL of a mixed ion exchange resin mixed with cation exchange resin and anion exchange resin in a ratio of 1: 1.

Then, the prepared conductive polymer solution was put into a hopper of a homogenization treatment equipment, homogeneous treatment was performed once at a high pressure of 1000 bar or more, a cooler was connected to the treated pipe, and a continuous cooling process was added at 10 to 20 ° C Respectively. This homogeneous treatment was repeated twice or more at a high pressure of 1000 bar or more.

Comparative Example

The same conductive polymer solution as in the above example was prepared, and homogeneous treatment was not performed.

Experimental Example 1: TEM analysis of conductive polymer solution

The TEM analysis result of the conductive polymer solution prepared in the above example is shown in Fig.

1, it can be confirmed that particles having a uniform particle diameter are dispersed in the conductive polymer solution according to the embodiment, and it can be confirmed that the particle diameter is 100 nm or less.

Experimental Example 2: Electrical Conductivity Measurement

The electrical conductivity of the films prepared by curing the conductive polymer solution prepared in the above Examples and Comparative Examples was measured. The results are shown in Fig.

2, it can be seen that the conductive polymer film produced by the present invention exhibits a higher electric conductivity than the conductive polymer film produced by the comparative example.

Experimental Example 3: Measurement of light transmittance and sheet resistance

The transmittance and sheet resistance of the films prepared by curing the conductive polymer solution prepared in the above Examples and Comparative Examples were measured. The results are shown in FIG.

Referring to FIG. 3, the conductive polymer film prepared by the present invention has a light transmittance of 82% or more at a sheet resistance of 80 Ω / sq and a higher light transmittance than that of the conductive polymer film prepared by the comparative example have.

Experimental Example 4: Haze measurement

The haze of the films prepared by curing the conductive polymer solution prepared in the above Examples and Comparative Examples was measured. The results are shown in FIG.

It can be confirmed that the conductive polymer film produced by the present invention has a haze of 1 or less.

Experimental Example 5: Measurement of b * value

With respect to the film prepared by curing the conductive polymer solution prepared in the above Examples and Comparative Examples, the measurement area of 2.5 x 2.5 cm was measured by using a haze meter (color difference meter) and a b * value at a visible light wavelength of 550 nm Respectively. The results are shown in FIG.

It can be seen that the conductive polymer film produced by the present invention has a low b * absolute value in the low resistance range as compared with the comparative example, which means that the film is less distinctive in color and improved in visibility.

Claims (12)

A conductive polymer particle having a particle diameter in the range of 10 to 200 nm,
Wherein the conductive polymer particles have a half width of 30 to 60 nm in the particle diameter distribution diagram of the conductive polymer particles.
The method according to claim 1,
Wherein the conductive polymer particles having a particle diameter in the range of 10 to 200 nm are not less than 90% by weight of the total conductive polymer particles.
delete The method according to claim 1,
Wherein the concentration of the conductive polymer particles is 1 to 5% by weight.
Homogenizing the conductive polymer solution under a high pressure condition of 1000 to 1800 bar or more,
The conductive polymer solution has a particle size distribution in the range of 10 to 200 nm,
Wherein the half width of the particle size distribution of the particles in the conductive polymer solution is 30 to 60 nm.
6. The method of claim 5,
Wherein at least 90% by weight of the total particles in the conductive polymer solution are in the range of 10 to 200 nm.
delete 6. The method of claim 5,
Wherein the homogenization step is repeated twice or more.
6. The method of claim 5,
The method further comprising the step of mixing the dopant after homogenizing the conductive polymer solution.
6. The method of claim 5,
Wherein the conductive polymer solution is homogenized and then filtered using a filtration membrane.
6. The method of claim 5,
Wherein the conductive polymer comprises a repeating unit represented by the following Formula 1:
[Chemical Formula 1]

In Formula 1,
X and Y each independently represent O, S, Si or N,
R ₁ and R ₂ each independently represent hydrogen, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryl group having 3 to 20 carbon atoms, or a heteroaryl group having 2 to 20 carbon atoms,
n is an integer from 2 to 2000,
Alternatively, R ₁ and R ₂ are bonded to each other to represent a fused ring structure.
6. The method of claim 5,
Wherein the conductive polymer is PEDOT: PSS.

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