KR20100125068A - The method for fabricating transparent conducting film from carbon nanotube and the transparent conducting film using the same - Google Patents

Abstract

PURPOSE: A manufacturing method of a transparent conductive film, and the transparent conductive film manufactured therefrom are provided to offer the strong adhesive force to the film. CONSTITUTION: A manufacturing method of a transparent conductive film using carbon nanotubes comprises the following steps: pre-treating the surface of substrate using ultraviolet rays and ozone(S300); spreading a solution dispersed with the carbon nanotubes on the substrate to form the transparent conductive film(S400); and post-treating the film using a mixed solution containing nitric acid(S500).

Description

A method for fabricating a transparent conductive film using carbon nanotubes and a transparent conductive film produced using the method {The method for fabricating transparent conducting film from carbon nanotube and the transparent conducting film using the same}

The present invention relates to a method for manufacturing a transparent conductive film using carbon nanotubes and to a transparent conductive film produced using the method. More specifically, the carbon undergoes a purification process and a dispersion process on a substrate subjected to pretreatment. Method of preparing a transparent conductive film using carbon nanotubes and post-treatment using a mixed solution containing nitric acid after uniformly coating the dispersion solution of nanotubes and the transparent conductive film produced using the method It is about.

Because of the unique structural, mechanical and electrical properties of carbon nanotubes, flexible conductive transparent films (TCFs) based on carbon nanotubes are excellent in display applications, still image recorders, solar cells, electro-optics, and solid state light emitting applications. Interest is on the rise, showing characteristics. To date, most of the known methods for growing carbon nanotubes, such as electric arc-discharge, laser vaporization, and chemical vapor deposition, are mostly small catalytic metal grains, plugs, etc. It contains many impurities, such as fullerene, amorphous or graphitic carbon grains.

Various methods for purifying carbon nanotubes containing such impurities are currently reported, but these methods partially destroy the carbon nanotubes and damage or fragment the walls of the carbon nanotubes.

In addition, very pure carbon nanotubes have to be dispersed in order to produce high adhesion TCF with low resistance and high permeability, but the large aspect ratio (> 1000) of carbon nanotubes and the strong anisotropic interaction (0.5 eV nm) ^-1 ) has a problem in that it is bundled in the form of rope-like bundles. Effective methods for dispersing carbon nanotubes at high concentrations without agglomeration include chemical functionalization, mechanically cutting nanotubes, using surfactants, and using small molecules or polymers. However, these methods cause structural damage of the carbon nanotubes by physically cutting or chemically processing the carbon nanotubes, thereby degrading the actual characteristics of the carbon nanotubes.

In addition, methods for fabricating TCFs from carbon nanotube solutions, such as dipping techniques, vacuum filtration, printing techniques, and spray coatings, can produce TCFs with uniform and strong adhesion. There are many limitations in making it. For example, the vacuum filtration method has an advantage in that the thickness of the film is easily controlled, but there are many restrictions on the size of the filter, which acts as an obstacle for a large area device. Spray coating or inkjet printing method has a problem that the nozzle is clogged, in the case of dipping technology there is a problem that the film is non-uniform.

Therefore, the problem to be solved by the present invention in order to solve the above problems, the coating of carbon nanotubes through a purification process and a dispersion process on a glass substrate or a plastic substrate, a glass substrate or a plastic substrate of a double layer structure coated with a thin transparent film It is to provide a method for producing a transparent conductive film using carbon nanotubes, and a transparent conductive film produced using the method that can produce a film having a strong adhesive force by using.

Another technical problem to be achieved by the present invention is to easily remove impurities through post-treatment of the transparent conductive film generated using carbon nanotubes, thereby improving conductivity while maintaining the transmittance of the transparent conductive film, carbon nanotubes. It is to provide a method for producing a transparent conductive film and a transparent conductive film produced using the method.

In addition, another technical problem to be achieved by the present invention is to use a method and a method for producing a transparent conductive film using carbon or notube, which can produce a pattern of a desired shape using a simple photolithography process and an etching process It is to provide a transparent conductive film produced by.

Problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

Method for producing a transparent conductive film using a carbon nanotube according to an embodiment of the present invention for achieving the above technical problem, the step of performing a pretreatment using ultraviolet and ozone on the surface of the substrate; Preparing a transparent conductive film by uniformly applying a solution in which carbon nanotubes are dispersed on the substrate; And performing a post-treatment of the prepared transparent conductive film using a mixed solution containing nitric acid.

In addition, the transparent conductive film according to another embodiment of the present invention for achieving the above technical problem is a transparent conductive film produced by using the method of manufacturing the transparent conductive film described above, pretreatment using ultraviolet and ozone A substrate performed; It includes a carbon nanotube layer coated on the substrate and subjected to a purification process and a dispersion process.

Specific details of other embodiments are included in the detailed description and the drawings.

According to the method of manufacturing a transparent conductive film using the carbon nanotubes according to the embodiment of the present invention as described above and the transparent conductive film produced using the method, one or more of the following effects are present.

First, a film having a strong adhesive force may be manufactured by coating a carbon nanotube through a refining process and a dispersion process on a glass substrate or a plastic substrate or a glass substrate or a plastic substrate having a thin transparent film coated thereon.

Second, by easily removing impurities through post-treatment of the transparent conductive film generated using carbon nanotubes, it is possible to improve conductivity while maintaining the transmittance of the transparent conductive film.

Third, the resulting transparent conductive film can be obtained using a photolithography and etch process to obtain a desired pattern without damaging the remaining carbon nanotubes.

The effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and only the embodiments make the disclosure of the present invention complete, and the general knowledge in the art to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. As used herein, “comprises” and / or “comprising” refers to the presence of one or more other components, steps, operations and / or elements. Or does not exclude additions. Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used in a sense that can be commonly understood by those skilled in the art. In addition, the terms defined in the commonly used dictionaries are not ideally or excessively interpreted unless they are specifically defined clearly.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to describe the present invention in more detail.

The carbon nanotubes used to fabricate the transparent conductive film described below will include both double-walled and multi-walled carbon nanotubes as well as single-walled carbon nanotubes.

1 is an overall flowchart of a method of manufacturing a transparent conductive film using carbon nanotubes according to an embodiment of the present invention.

First, carbon nanotubes (CNTs) produced by an arc discharge method were used as a material for manufacturing a transparent conductive film according to an embodiment of the present invention. In the case of the used carbon nanotubes, 25 bundles of carbon nanotubes having an average length of 5-7 μm and an average diameter of 1.3 nm were bundled in the factory. These materials were removed from most of the amorphous carbon and the metal catalyst, and it was confirmed by thermogravimetry analysis (TGA) that the purity reached about 85 wt%. In addition, the remaining residues are impurities including carbon, such as graphitic flakes, which are separated into small pieces during the purification and dispersion processes described below, which are formed after film formation. It will get stuck inside the film, which will adversely affect the conductivity of the film. Therefore, it is required to remove the graphite flakes without damaging the carbon nanotubes, which will be described in detail through the process described below.

Referring to FIG. 1, first, a process of purifying carbon nanotubes is performed (S100).

In order to perform purification, dry oxidation of carbon nanotubes is performed at high temperature. Dry oxidation is suitable for about 10 hours at a temperature of 360 ℃ at atmospheric pressure.

In addition, acid treatment is performed by mixing dry oxidized carbon nanotubes with 4 M (molar concentration) nitric acid solution and then performing ultrasonic treatment at 20 ° C. for 2 hours in a tank-type ultrasonic generator (Ultrasonicator). Do The carbon nanotubes are filtered from the solution containing the carbon nanotubes subjected to the sonication using a vacuum filter of a membrane filter and then washed with DI (Deionized water). After repeating the filtering process several more times, the membrane filter may be dried for about 3 hours and the Bucky Paper of carbon nanotubes may be extracted from the membrane filter. Such bucky paper may be used after the heat treatment for 3 hours at a temperature of about 360 ℃ after drying, the dispersion process to be described later.

The thermogravimetric analysis (TGA) shows that carbon nanotubes subjected to the aforementioned purification process start to burn after about 500 ° C., whereas carbon nanotubes that do not undergo the purification process start to burn from about 450 ° C., which is lower temperature. It was confirmed through. This is because impurities in the unrefined carbon nanotubes generate excessive heat on the surface of the tubes, making them burnable at lower temperatures.

After performing the above-described purification process, a process of dispersing a solution containing carbon nanotubes is performed (S200). When the dispersion process is not performed, carbon nanotubes are present in the form of bundles. Therefore, in order to perform the dispersion process, after soaking the purified carbon nanotubes in the DCB (1,2-dichlorobenzene) solution it can be again subjected to ultrasonic treatment in the ultrasonic generator. Herein, the concentration of the DCB solution is preferably 0.1 mg / ml, and the sonication is preferably performed at a temperature of 20 ° C. for about 3 hours.

After sonication for about 3 hours, the carbon nanotube solution dispersed in DCB was homogeneous black, and experimentally confirmed that it is stable even after 24 hours without any precipitation. This is because the DCB forms a negatively charged molecule around the carbon nanotubes, making it stable in a state where no agglomeration occurs due to the repulsive force between charges generated through the ultrasonic treatment in the DCB. Due to the similar structural properties between DCB and carbon nanotubes, the solvent molecules (DCB) align well with carbon nanotubes during sonication.

Of course, there are dispersion methods using polymers, surfactants, and amines other than DCB, but the surfactants or polymers used in these methods surround the carbon nanotubes to form an insulating layer. This causes a sudden drop in the conductivity of the film. Moreover, it is very difficult to remove the surfactant or the polymer after film formation, which increases the cost of the process and may cause the film to peel off from the substrate. Therefore, there is an advantage that does not affect the original structure of the carbon nanotubes by dispersing the purified carbon nanotubes in the DCB solution, which can be confirmed with reference to FIG.

FIG. 6 shows a scanning electron microscope (SEM) photograph showing the quality of carbon nanotubes in a DCB solution produced by a dispersion process according to an embodiment of the present invention. Referring to the photograph of FIG. 6, it can be seen that the carbon nanotube-dispersed solution is composed of a mixture of well-dispersed carbon nanotubes and a small-sized bundle forming a three-dimensional network on a substrate. As can be seen from the photograph of FIG. 6, the quality of the dispersed carbon nanotubes may depend on the difference in diameter of the carbon nanotubes, purity and / or solvent (DCB) suitable for a liquid-based process.

Of course, the solution used in the dispersion process may be a DCB (1,2-dichlorobenzene) solution, but the embodiment of the dispersion process of the present invention is not limited thereto. That is, after dipping the extracted bucky paper in a mixed solution of PVP and DI (Deionized Water), the ultrasonic dispersion is performed to perform the first dispersion, and the PVP is removed by vacuum filtering. As a result, a bucky paper is produced. After immersing the bucky paper in ethanol and performing a second dispersion, which is subjected to sonication again, it is left to settle for a certain period of time to precipitate impurities. It can be used to

Through the above-described dispersion process, even if the carbon nanotubes are left in a dispersion solution such as DCB, it is possible to maintain a stable state (Stable) that does not form a bundle.

Meanwhile, after performing the dispersion process, a transparent conductive film should be manufactured. For this, pretreatment using ultraviolet and ozone may be performed on the surface of the substrate (S300). The pretreatment process will be described in detail with reference to FIG. 2.

2 is a flowchart of a pretreatment process in a method of manufacturing a transparent conductive film using carbon nanotubes according to an embodiment of the present invention.

First, the substrate is irradiated with ultraviolet light of a single wavelength at a predetermined distance from the substrate for a predetermined time (S310). The surface of the substrate is changed from hydrophobic to hydrophilic by irradiation of ultraviolet light. The wavelength of ultraviolet light is preferably 172 nm single wavelength, and irradiation in the atmosphere for about 10 minutes at atmospheric pressure of 760 mTorr and temperature of 25 ℃.

Ozone (O ₃ ) gas generated by the irradiation can be removed using nitrogen gas (S320).

The substrate used in the embodiment of the present invention is a double layer coated with all plastic substrates, glass substrates, and thin transparent films, including a flexible and highly transparent polyethylene naphthalate (PEN) or polyethylene sulfonate (PES) substrate. It is preferable to use a glass substrate and a plastic substrate having a structure.

After performing the pretreatment process on the substrate, a transparent conductive film may be manufactured using the solution in which the carbon nanotubes generated by the S200 process are dispersed and the substrate on which the pretreatment process is completed (S400). A process of manufacturing the transparent conductive film will be described in detail with reference to FIGS. 3 and 4.

3 is a flow chart of the spin coating in the manufacturing process of the transparent conductive film according to the embodiment of the present invention, Figure 4 is a flow chart of the slit coating in the manufacturing process of the transparent conductive film according to the embodiment of the present invention.

Referring to FIG. 3, the solution in which the carbon nanotubes generated by the S200 process of FIG. 1 is dispersed is gradually dropped onto the substrate on which the pretreatment is performed by the S300 process (S410). If the dispersed solution is uniformly spread on the substrate is rotated while changing the rotational speed of the substrate (S420). The substrate coated by the dispersed solution is dried for about 3 minutes at a temperature of 30 to 100 ℃ (S430). The above-mentioned rotating step (S420) and drying step (S430) are repeatedly performed until the substrate obtains a predetermined level of transmittance (S440).

After the coating, the film of carbon nanotubes showed a transmittance of 93% at a wavelength of 550 nm at a thickness of 32 nm. Through repeated coatings, the thickness and transmittance of the film were adjusted, thereby allowing for optimized optical properties and sheet resistance. That is, the thickness of the film can be precisely controlled by adjusting the concentration of carbon nanotubes or the speed of spin coating in a solution in which carbon nanotubes are dispersed.

Referring to FIG. 4, a solution in which carbon nanotubes are dispersed is uniformly coated on the substrate on which the pretreatment is performed by the S300 process of FIG. Drying the substrate coated by the dispersed solution at a temperature of 30 to 100 ° C. for about 3 minutes (S460), and drying the substrate (S450) and drying (S450) as described above until the substrate obtains a certain level of permeability. S460) is repeatedly performed (S470).

While spin coating has the potential to cause loss of solution as it rotates, slit coating has the advantage that the entire surface can be uniformly coated at low cost by using only the required amount of solution, and the process is simple and can be used for large areas. have.

In order to improve the transmittance of the transparent conductive film generated through the above process, a post-treatment process may be performed using a mixed solution containing nitric acid (S500). The post-treatment process of the transparent conductive film will be described in detail with reference to FIG. 5.

5 is a flowchart of a post-treatment process in a method of manufacturing a transparent conductive film using carbon nanotubes according to an embodiment of the present invention.

First, the transparent conductive film produced by the S400 process is immersed in a solution in which IPA (isopropyl alcohol) and HNO ₃ are mixed (S510). At this time, the ratio of the mixed solution is preferably IPA and HNO ₃ is mixed in a volume ratio of 3: 1 to 100: 1, soaking time is preferably 20 to 120 minutes.

After performing the S510 process, the IPA is evaporated at room temperature after washing using the IPA (S520).

Meanwhile, a pattern may be formed on the transparent conductive film on which the above-described post-treatment process is performed by a general photolithography process and a process using a developer (S600).

Looking at the general photolithography process, after applying the photoresist (PR) to the front of the resulting transparent conductive film, using a mask to irradiate UV to only the portion to form a pattern, and the UV-irradiated film developer ( developer) and the hard baking of the resistor at a high temperature, and then remove the remaining carbon nanotubes using oxygen plasma. The stripper is used to form the pattern by removing the photoresist.

In addition, referring to the process using a developer, after applying photoresist (PR) to the entire surface of the resulting transparent conductive film, and irradiating UV only to the portion to form a pattern using a mask, the UV-irradiated film After developing in a developer, the carbon nanotubes are removed from the substrate by washing. The developer serves to weaken the adhesion between the film and the substrate. Finally, a stripper is used to remove the photoresist to form a pattern, which is illustrated in FIG. 7. Referring to FIG. 7, it can be seen that a pattern is formed by a process using a developer.

Hereinafter, the improved characteristics of the transparent conductive film produced as a result of the above-described post-treatment process will be described with reference to the drawings.

8 is a graph showing the correlation between the thickness and the light transmittance of the transparent conductive film as a result of the post-treatment process according to an embodiment of the present invention.

Referring to FIG. 8, it can be seen that as the thickness of the PEN substrate increases, the transmittance decreases slowly. In FIG. 8, only the PEN substrate is shown, but similar results may be obtained for the PES substrate.

9 is a view showing a correlation between the sheet resistance and the transmittance of the spin-coated film and the film subjected to the post-treatment process before performing the post-treatment process on the PEN substrate and the PES substrate according to an embodiment of the present invention.

Referring to FIG. 9, the sheet resistance decreased by about 6 times by the post-treatment process irrespective of each substrate, and the decrease ratio was lowered as the film thickness increased. In addition, it can be seen that the correlation between the sheet resistance and the transmittance of the film subjected to the post-treatment process is almost linear. In this experiment, after using IPA-HNO ₃ of a transparent conductive film made from a PEN substrate, the result was 110 Ω / □ of sheet resistance for 80% transmittance and 200 Ω / □ of sheet resistance for 90% transmittance at 550 nm. Got. Through post-treatment using IPA-HNO ₃ of the transparent conductive film produced on the PES substrate, the sheet resistance was 100 Ω / □ for 80% transmittance and 193 Ω / □ for 90% transmittance at 550 nm.

These experimental results clearly show that they are suitable for commercial applications such as touch screens (TS: 500 Ω / □, 85% T) and flexible displays (FD: 100 Ω / □, 80% T).

FIG. 10 is a view illustrating a correlation between wavelength and light transmittance of a spin coated film before performing a post-treatment process on a PEN substrate according to an embodiment of the present invention and a film subjected to the post-treatment process.

The picture inserted in FIG. 10 shows the flexibility and optical transparency of the carbon nanotube-based transparent conductive film which has been subjected to the post-treatment process. In FIG. 10, the sheet resistance (Rs) of the coating-only film before the post-treatment process is 1330 Ω / □ over the region of the visible wavelength and the infrared wavelength, but the 60-minute post-treatment process is performed. In this case, it can be seen that the sheet resistance Rs is reduced to 200 Ω / □. In contrast to ITO in which the peak value of transparency is observed around 550 nm, it can be seen that the transparent conductive film according to the embodiment of the present invention exhibits high transparency as it approaches the infrared region of the electromagnetic spectrum.

11 (a), 11 (b) and 11 (c) are photographs showing SEM side views of a spin coated film prior to performing a post treatment process on a PEN substrate (thickness 110 nm) according to an embodiment of the invention. 11 (d) is a photograph showing an SEM side view of a film that is subjected to a post-treatment process.

Referring to FIGS. 11 (a), 11 (b) and 11 (c), it can be seen that carbon nanotubes protrude from the substrate from several nm to several mm in the circled portion. This lowers the density of the carbon nanotubes on the surface of the substrate and constrains the carbon nanotubes from contacting each other, resulting in an increase in sheet resistance. In addition, this protrusion can increase the surface roughness and instability of the film. However, as shown in FIG. 11 (d), it can be seen that the protrusion of the surface disappeared after performing the post-treatment using IPA-HNO ₃ for 60 minutes.

This fact can also be confirmed through the AFM analysis of FIG. 12.

12 is a diagram illustrating AFM topography and line profile of a film subjected to a post-treatment process according to an embodiment of the present invention.

Through the line profile of the AFM image, the average surface roughness was measured at about 6 nm after the post-treatment, which is lower than about 12 nm, which is the average surface roughness of the coating-only film before performing the post-treatment process. From these experimental results, the post-treatment process using IPA-HNO ₃ mixed solution softened the carbon nanotubes so that the protrusions disappeared.

On the other hand, as another effect of the post-treatment process using the IPA-HNO ₃ mixed solution, it is possible to remove impurities embedded in the carbon or notube film, which will be described with reference to FIGS. 13 (a) and 13 (b).

FIG. 13 (a) is a photograph showing an SEM plan view from above of a spin coated film before performing a post-treatment process on a PEN substrate according to an embodiment of the present invention, and FIG. 13 (b) shows a post-treatment process. It is a photograph showing the SEM plan view of the film viewed from above.

13 (a), it can be seen that even though the carbon nanotubes have a purity of about 95% through a purification process, a small amount of impurities still appear in the film, which actually lowers the conductivity. However, in Figure 13 (b), it can be seen that impurities are reduced. The ideal post-treatment time was about 60 minutes, and the increase or decrease of post-treatment time did not increase the flatness or decrease the sheet resistance. It was confirmed that the film layer remained more strongly attached to the surface of the PEN substrate or the PES substrate.

The adhesion or stability of these films depends mainly on the surface energy of the pretreated substrate with UV-O ₃ . In the case of dispersions of carbon nanotubes prepared from charged surfactants such as sodium or lithium dodecyl sulfate (SDS, LDS) or cetyl trimethylammonium bromide (CTAB), films with low conductivity and weak adhesion to the substrate It is known to be made.

FIG. 14 is a view illustrating Micro Raman spectra of a spin coated film and a film subjected to the post-treatment process before performing the post-treatment process according to the embodiment of the present invention.

Referring to FIG. 14, no new peak was observed for the post-treatment using the IPA-HNO ₃ mixed solution in the observation region of the post-treated film. It can be seen that no additional peaks are observed in the measured spectral region representing the original structure of the carbon nanotubes. Moreover, although no peak shift in RBM or G-band was observed, no significant increase in D-band was seen.

FIG. 15 is a view illustrating a change in sheet resistance and bending angle of a carbon nanotube film on a PEN substrate and a PES substrate according to an embodiment of the present invention.

Referring to FIG. 15, even if the bending angle of the film is increased, the increase in sheet resistance is very small.

Although the properties of the film are highly dependent on the properties of the material such as purity, diameter, impurities, metallicity and degree of dispersion, the results of this experiment can provide a systematic way of making films with excellent properties. In general, the film subjected to the post-treatment using a strong acid such as nitric acid weakens the adhesion between the substrate and the film, resulting in peeling the film from the substrate, making it difficult to be used as an actual device. However, it can be seen that through the pretreatment process and the post-treatment process used in the embodiment of the present invention, the conductivity increased up to about 4 times without compromising optical transparency or stability.

Carbon nanotubes used to fabricate the transparent conductive film described above may include both single-walled, double-walled, and multi-walled carbon nanotubes.

On the other hand, the transparent conductive film produced using the method of manufacturing a transparent conductive film from the carbon nanotubes described above includes a substrate subjected to pretreatment using ultraviolet rays and ozone, and a carbon nanotube layer subjected to a purification process and a dispersion process. It can be configured, the scope of the present invention also extends to the transparent conductive film produced by using the method for producing a transparent conductive film described above.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be appreciated that one embodiment is possible. Accordingly, the true scope of the present invention should be determined by the technical idea of the claims.

1 is an overall flowchart of a method of manufacturing a transparent conductive film using carbon nanotubes according to an embodiment of the present invention.

2 is a flowchart of a pretreatment process in a method of manufacturing a transparent conductive film using carbon nanotubes according to an embodiment of the present invention.

3 is a flow chart of the spin coating in the manufacturing process of the transparent conductive film according to the embodiment of the present invention, Figure 4 is a flow chart of the slit coating in the manufacturing process of the transparent conductive film according to the embodiment of the present invention.

5 is a flowchart of a post-treatment process in a method of manufacturing a transparent conductive film using carbon nanotubes according to an embodiment of the present invention.

FIG. 6 shows a scanning electron microscope (SEM) photograph showing the quality of carbon nanotubes in a DCB solution produced by a dispersion process according to an embodiment of the present invention.

7 is a view showing a photo pattern formed by the process using a developer according to an embodiment of the present invention.

8 is a graph showing the correlation between the thickness and the light transmittance of the transparent conductive film as a result of the post-treatment process according to an embodiment of the present invention.

9 is a view showing a correlation between the sheet resistance and the transmittance of the spin-coated film and the film subjected to the post-treatment process before performing the post-treatment process on the PEN substrate and the PES substrate according to an embodiment of the present invention.

FIG. 10 is a view illustrating a correlation between wavelength and light transmittance of a spin coated film before performing a post-treatment process on a PEN substrate according to an embodiment of the present invention and a film subjected to the post-treatment process.

11 (a), 11 (b) and 11 (c) are photographs showing SEM side views of a spin coated film prior to performing a post treatment process on a PEN substrate (thickness 110 nm) according to an embodiment of the invention. 11 (d) is a photograph showing an SEM side view of a film that is subjected to a post-treatment process.

12 is a diagram illustrating AFM topography and line profile of a film subjected to a post-treatment process according to an embodiment of the present invention.

FIG. 13 (a) is a photograph showing an SEM plan view from above of a spin coated film before performing a post-treatment process on a PEN substrate according to an embodiment of the present invention, and FIG. 13 (b) shows a post-treatment process. It is a photograph showing the SEM plan view of the film viewed from above.

FIG. 14 is a diagram illustrating Micro Raman spectra of a spin coated film and a film subjected to a post treatment process before performing a post treatment process according to an embodiment of the present invention.

FIG. 15 is a view illustrating a change in sheet resistance and bending angle of a carbon nanotube film on a PEN substrate and a PES substrate according to an embodiment of the present invention.

Claims (19)

Performing pretreatment using ultraviolet and ozone on the surface of the substrate; Preparing a transparent conductive film by uniformly applying a solution in which carbon nanotubes are dispersed on the substrate; Method for producing a transparent conductive film using a carbon nanotube comprising the step of performing a post-treatment using the mixed solution containing the nitric acid prepared transparent conductive film. The method of claim 1, Wherein: Method of manufacturing a transparent conductive film using a carbon nanotube, comprising one of a glass substrate, a plastic substrate, a glass substrate coated with a transparent thin film, and a plastic substrate coated with a transparent thin film. The method of claim 1, Performing the pretreatment, Irradiating with ultraviolet light of a single wavelength at a distance from the substrate for a predetermined time; Method of manufacturing a transparent conductive film using a carbon nanotube, comprising the step of removing ozone generated by the irradiation. The method of claim 1, Producing the transparent conductive film, Dropping the solution in which the carbon nanotubes are dispersed on the substrate; Rotating the substrate while changing the rotational speed of the substrate when the dispersed solution is uniformly spread on the substrate; Drying the substrate coated with the dispersed solution at a temperature of 30 to 100 ° C. for a predetermined time; And repeating the step of rotating and drying until the substrate obtains a certain level of transmittance, using the carbon nanotubes to produce a transparent conductive film. The method of claim 1, Producing the transparent conductive film, Coating the solution in which the carbon nanotubes are dispersed by using a slit to control a thickness in nanometers; Drying the substrate coated with the dispersed solution at a temperature of 30 to 100 ° C. for a predetermined time; And repeating the coating and drying until the substrate obtains a certain level of transmittance, using the carbon nanotubes. The method of claim 1, Performing the post-processing, Dipping the prepared transparent conductive film in a solution in which IPA (isopropyl alcohol) and HNO ₃ are mixed; Method of manufacturing a transparent conductive film using carbon nanotubes comprising the step of evaporating the IPA at room temperature after washing the prepared transparent conductive film using the IPA. The method of claim 6, The dipping step, The IPA and the HNO ₃ is immersed in a solution mixed in a volume ratio of 3: 1 to 100: 1 for 20 to 120 minutes, a method for producing a transparent conductive film using carbon nanotubes. The method of claim 1, Before performing the pretreatment, Purifying the carbon nanotubes; A method for producing a transparent conductive film using carbon nanotubes, further comprising the step of performing a dispersion treatment on the purified carbon nanotubes. The method of claim 8, The purification step, Dry Oxidation of the carbon nanotubes at a high temperature; Mixing the dry oxidized carbon nanotubes with a nitric acid solution and then performing ultrasonic treatment in a bath-type ultrasonic generator; Producing a transparent conductive film using carbon nanotubes, comprising extracting carbon nanotubes from a solution containing the carbon nanotubes subjected to the ultrasonic treatment by using a bucky paper by vacuum filtering. How to. The method of claim 9, The performing of the distribution process, Dipping carbon nanotubes extracted using the bucky paper in a DCB (1,2-dichlorobenzene) solution to perform a dispersion treatment by performing an ultrasonic treatment. The method of claim 9, The performing of the distribution process, Immersing the bucky paper in a mixed solution of PVP and DI (Deionized Water) and then performing a first dispersion in which sonication is performed; Generating a bucky paper by removing the PVP from the mixed solution in which the primary dispersion was performed using vacuum filtering; Performing a secondary dispersion in which the carbon nanotubes extracted using the bucky paper are soaked in ethanol and then subjected to sonication; Leaving the solution produced by the secondary dispersion for a predetermined time to precipitate impurities downward, and using the remaining solution on the top to produce the transparent conductive film. How to make. The method of claim 1, A method of manufacturing a transparent conductive film using carbon nanotubes, further comprising the step of forming a pattern by a process using a photolithography process and a developer using the post-processing transparent conductive film. 13. The method of claim 12, The photolithography process, Applying a photoresist (PR) on the entire surface of the transparent conductive film, and then irradiating UV only to a portion where a pattern is to be formed using a mask; Developing the UV-irradiated film in a developer, hard baking the resistor, and then removing residual carbon nanotubes using an oxygen plasma; Removing the photoresist using a stripper to form a pattern, the method of manufacturing a transparent conductive film using carbon nanotubes. 13. The method of claim 12, The process using the developer, Applying a photoresist (PR) on the entire surface of the transparent conductive film, and then irradiating UV only to a portion where a pattern is to be formed using a mask; Developing the UV-irradiated film in a developer, and then removing carbon nanotubes from the substrate by washing; Removing the photoresist using a stripper to form a pattern, the method of manufacturing a transparent conductive film using carbon nanotubes. A transparent conductive film produced using the method of any one of claims 1 to 14, A substrate on which pretreatment is performed using ultraviolet and ozone; The transparent conductive film is coated on the substrate and comprises a carbon nanotube layer subjected to a purification process and a dispersion process. The method of claim 15, The transparent conductive film, After the IPA (isopropyl alcohol) and HNO ₃ is immersed in a solution mixed in a volume ratio of 3: 1 to 100: 1 for 20 minutes to 120 minutes to perform a post-treatment process in which the IPA is evaporated. The method of claim 15, Wherein: A transparent conductive film comprising one of a glass substrate, a plastic substrate, a transparent thin film coated glass substrate, and a transparent thin film coated plastic substrate. The method of claim 15, The purification process, After dry oxidation at high temperature, carbon nanotubes are mixed with nitric acid solution and subjected to ultrasonic treatment. Transparent conductive film, which is performed by extracting carbon nanotubes using a paper). The method of claim 18, The dispersion process, And dipping the bucky paper into a DCB (1,2-dichlorobenzene) solution or a mixed solution of PVP and DI (Deionized Water), followed by sonication.

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