KR101486636B1 - Light transmittance composite film and method for fabricating the same - Google Patents

Abstract

And a method for producing the same. The light-transmitting composite film includes a metal nanowire film and a carbon nanotube film disposed on the metal nanowire film. The method of manufacturing a light-transmitting composite film includes forming a metal nanowire film, Forming a carbon nanotube film on the surface of the metal nanowire film, wherein the metal nanowires contained in the metal nanowire film exist in a state of being connected to each other, The carbon nanotubes are connected to the metal nanowires to cover the substrate in the empty space and disperse heat generated locally in the metal nanowires to uniformly heat the entire surface of the substrate, And the carbon nanotubes are bonded to the metal nanowires It is possible to reduce the haze generated from the film to improve the visibility of the film.

Description

TECHNICAL FIELD The present invention relates to a light transmittance composite film,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a composite film and a method for manufacturing the same, and more particularly, to a composite film for light transmission and a method of manufacturing the same.

Indium tin oxide (ITO) has excellent optical and electrical properties and is applied as a light transmitting heat-generating film that removes moisture or germs from airplanes, automobiles, refrigerator showcases, and window glass of buildings. Such an ITO film has a sheet resistance of about 10? /? Or less at a transmittance of 90% or more.

However, the ITO film tends to be fragile, requires a high vacuum at the time of manufacture, and is difficult to apply in a large area, resulting in a high manufacturing cost. Therefore, studies on a material film that can replace the ITO film have been actively conducted.

Recently, silver nanowires (AgNW) and single walled carbon nanotubes (SWCNTs) have been studied as alternative materials for such ITO films. Such silver nanowires and single-walled carbon nanotubes have high transmittance and low resistance, are flexible and do not break easily, can be manufactured in a solution state, and are easy to apply in a large area.

Silver (Ag) is one of the metals with the lowest resistance, and exhibits high heat-generating properties. However, silver nanowires having a nanometer-level diameter have a low melting point and easily break into high heat, resulting in poor stability of heat generation.

On the other hand, single-walled carbon nanotubes have a very high stability due to heat generation due to a covalent bond of carbon-carbon (C-C). However, the single-walled carbon nanotube film has a very high resistance as compared with the ITO film or the silver nanowire film, and thus there is a problem that a high voltage is required for use as a heat-generating film.

Korean Patent Registration No. 10-1091744 discloses a conductive film production method using a metal wire and a conductive film. The conductive film may be prepared by pretreating carbon nanotubes through at least one of cutting by ultrasonic waves and chemical reaction with acids, adding an ionic liquid material to a solvent, dispersing the carbon nanotubes in the solvent, Mixing a metal wire with a carbon nanotube dispersion produced by dispersing carbon nanotubes in the solvent, and coating the dispersion with the metal wire on a substrate to form an electrode layer.

Since the above method is a method of coating a dispersion on which a metal wire and a carbon nanotube are mixed, there is a high probability that the carbon nanotubes are interposed between the metal wires. Therefore, since the metal wire can exhibit a very high resistance due to the contact resistance generated at the point where the metal wire and the carbon nanotube are in contact, it is difficult to use it as a heat generating film.

SUMMARY OF THE INVENTION The present invention provides a light-transmitting composite film having excellent exothermic characteristics under low voltage and improved heat stability, and a method for producing the same.

According to one aspect of the present invention, there is provided a light-transmitting composite film. The film includes a metal nanowire film and a carbon nanotube film disposed on the metal nanowire film.

The metal nanowires contained in the metal nanowire film are randomly arranged such that a part of one metal nanowire overlaps with another part of another metal nanowire and can be connected to each other.

The metal nanowires contained in the metal nanowire film are randomly arranged, and the carbon nanotubes contained in the carbon nanotube film are connected to each other on the surface of the metal nanowire to form a network structure.

And a carbon nanotube film disposed under the metal nanowire film.

And a protective film disposed on the carbon nanotube film.

The protective film may contain a light-transmitting polymer.

The metal nanowire may be any one of gold, silver, platinum, copper, and nickel nanowires.

The carbon nanotube may be a single-walled carbon nanotube, a double-walled carbon nanotube, or a multi-walled carbon nanotube.

A metal nanowire film, a first electrode disposed on one end of the carbon nanotube film, and a second electrode disposed on the other end of the metal nanowire film and the carbon nanotube film.

According to one aspect of the present invention, there is provided a method of manufacturing a light-transmitting composite film. The method includes forming a metal nanowire film and forming a carbon nanotube film on the metal nanowire film, wherein the carbon nanotube contained in the carbon nanotube film is formed on the metal nanowire film And is formed so as to cover the surface of the metal nanowires while being connected to each other at the surface of the metal nanowires.

The method may further include forming a carbon nanotube film before forming the metal nanowire film.

Forming a carbon nanotube film on the metal nanowire film, and then forming a protective film on the carbon nanotube film.

According to the present invention, the carbon nanotubes are arranged so as to form a tight network structure on the surface of the metal nanowires, so that the carbon nanotubes connect the metal nanowires to disperse the heat generated from the metal nanowires. This makes it possible to uniformly generate heat on the entire surface of the substrate, thereby exhibiting stable heat generation characteristics.

In addition, the carbon nanotubes may contribute to improving the visibility of the film by removing haze generated from the metal nanowires.

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

1A is a perspective view of a light-transmitting composite film according to an embodiment of the present invention.
1B is a perspective view of a light-transmitting composite film according to another embodiment of the present invention.
2 is a plan view of a light-transmitting composite film according to an embodiment of the present invention.
3 is a cross-sectional view of a light-transmitting composite film according to another embodiment of the present invention.
4 is a flowchart illustrating a manufacturing process of a light-transmitting composite film according to an embodiment of the present invention.
FIGS. 5A and 5B are SEM images showing the silver nanowire film of Comparative Example 1 and the carbon nanotube film of Comparative Example 2. FIG.
6A and 6B are SEM images showing a light-transmitting composite film according to Comparative Example 3. Fig.
7A and 7B are SEM images showing a light-transmitting composite film according to an embodiment of the present invention.
FIG. 8 is a graph showing a temperature change according to a voltage of a silver nanowire film of Comparative Example 1. FIG.
9 is a graph showing the temperature change of the carbon nanotube film of Comparative Example 2 according to the voltage.
10A and 10B are graphs showing changes in temperature of a light-transmitting composite film of Comparative Example 3 and a light-transmitting composite film according to an embodiment of the present invention, respectively.
FIGS. 11A and 11B are graphs showing changes in temperature of a silver nanowire film of Comparative Example 1 and a light-transmitting composite film according to an embodiment of the present invention, according to a voltage.
FIGS. 12A and 12B are SEM images illustrating heat generation according to voltage application of the light-transmitting composite film according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It is to be understood, however, that the present invention is not limited to the embodiments described herein but may be embodied in other forms and includes all equivalents and alternatives falling within the spirit and scope of the present invention.

When a layer is referred to herein as being "on" another layer or substrate, it may be formed directly on another layer or substrate, or a third layer may be interposed therebetween. In the present specification, directional expressions of the upper side, upper side, upper side, and the like can be understood as meaning lower, lower, lower, and the like according to the standard. That is, the expression of the spatial direction should be understood in the relative direction and should not be construed as limiting in the absolute direction.

In the drawings, the thicknesses of the layers and regions may be exaggerated or omitted for the sake of clarity. Like reference numerals designate like elements throughout the specification.

1A is a cross-sectional view of a light-transmitting composite film according to an embodiment of the present invention.

2 is a plan view of a light-transmitting composite film according to an embodiment of the present invention.

Referring to FIGS. 1A and 2, a substrate 10 may be disposed. The substrate 10 may be made of a light transmissive material. For example, the substrate 10 may be an inorganic substrate such as glass, sapphire, or quartz, or may be an inorganic substrate such as PET (polyethylene terephthalate), polyethylene naphthalate (PEN), polyether sulfonate (PES), polymethyl methacrylate Or an organic material substrate such as polycarbonate (PC). However, the present invention is not limited thereto.

A metal nanowire film (20) is disposed on the substrate (10). The metal nanowire film 20 may contain a plurality of metal nanowires 21. The metal nanowires 21 may be any of nanowires selected from silver, gold, platinum, copper, and nickel. The metal nanowires 21 may be randomly arranged in the film 20. At this time, the metal nanowires 21 may be arranged so that a part thereof overlaps with each other. That is, a portion of one metal nanowire may be arranged to overlap with a portion of another metal nanowire, and may be directly connected to each other.

A carbon nanotube film (30) is disposed on the metal nanowire film (20). The carbon nanotube film 30 may contain carbon nanotubes. For example, the carbon nanotubes 31 contained in the carbon nanotube film 30 may be single wall carbon nanotubes, double wall carbon nanotubes, or multiwall carbon nanotubes. However, the present invention is not limited thereto, and various known carbon nanotubes can be used.

The carbon nanotubes 31 may be connected to each other with a tight network structure. The carbon nanotubes 31 may cover the surfaces of the metal nanowires 21.

As described above, the metal nanowires 21 are connected to each other, and the carbon nanotubes 31 may exist in a form covering the surface of the metal nanowires 21. In this case, due to the metal nanowires 21 connected to each other, a large current can flow due to a low resistance, so that heat generation is easy, and the heat generated by the current can disperse and discharge the carbon nanotubes 31 have.

Since the metal nanowires 21 have a nanometer size, they have a lower melting point than the melting point inherent in bulk metals. For example, when the metal nanowire 21 is a silver nanowire, the intrinsic melting point of silver having a bulk shape is very high at 961 ° C., while the melting point of nanometer-sized silver nanowires is about 150 ° C. to 200 ° C. Lower.

Therefore, when a voltage is applied to the substrate 10 on which only the metal nanowire film 20 is disposed, the heat generated in the metal nanowires 21 by the flow of current flows to the heat generated on the average surface of the substrate 10 So that the metal nanowires 21 may melt in the heat, resulting in breakage. On the other hand, the carbon nanotube 31 has high stability against heat due to strong covalent bonding of carbon-carbon (C-C) and has excellent thermal conductivity at the same time.

Therefore, when the carbon nanotubes 31 are arranged on the surface of the metal nanowires 21 so as to form a tight network structure, the carbon nanotubes 31 connect between the metal nanowires 21, The heat generated from the nanowires 21 can be dispersed. As a result, uniform heat generation occurs on the entire surface of the substrate 10, and stable heat generation characteristics can be exhibited.

The metal nanowires 21 have a low resistance, while the thermal stability is poor. The carbon nanotubes 31 have the advantages of excellent thermal stability and high thermal conductivity, and high resistance. In this case, when the carbon nanotubes 31 are arranged on the surface of the metal nanowires 21 in a network structure, the thermal conductivity of the carbon nanotubes 31 is about twice (~ 6000 W / mK) So that the heat generated from the metal nanowires 21 is rapidly transferred to the substrate 10 or the periphery to induce uniform heat generation and the temperature of the metal nanowires 21 is reduced through rapid heat transfer, And can also serve to protect the metal nanowires 21 having low stability.

In addition, since the carbon nanotubes 31 cover the surface of the metal nanowires 31, haze generated from the metal nanowires 21 can be removed to improve the visibility of the film.

The protective film 40 may be disposed on the carbon nanotube film 30. The protective film 40 may be employed for various applications. The protective film 40 may be made of a light transmitting polymer material. For example, the protective film 40 may be made of a material selected from the group consisting of PET (PolyEthylene Terephthalate), PI (Polyimide), PAI (Polyamide Imide), PBI (Polybenzimidazole), OPP (Oriented PolyPropylene), BOPP Alcohol, PVB (Polyvinyl Butyryl), PVDF (Polyvinylidene Fluoride), TPE (Thermo Plastic Elastomer), EVA (Ethylene Vinyl Acetate), EEA (Ethylene-ethyl Acrylic Acid), PE (Polyethylene), ETFE Tetrafluoro Ethylene), PPQ (Polyphenylquinoxaline), PBO (Polybenzoxazole) and PBT (Polybutylene Terephthalate).

The light-transmitting composite film according to the present invention can be used as a moisture-removing film on a conductive transparent electrode used in an electronic device such as a solar cell or a light emitting diode, or on a glass used for an automobile or an aircraft.

1B is a cross-sectional view of a light-transmitting composite film according to another embodiment of the present invention.

Referring to FIG. 1B, a first carbon nanotube film 30a disposed on a substrate 10 and a second carbon nanotube film 30b disposed on the first carbon nanotube film 30a The metal nanowire film 20 may be interposed.

The first and second carbon nanotube films 30a and 30b contain carbon nanotubes and the metal nanowire film 20 may include a plurality of metal nanowires.

In this case, since the carbon nanotubes are closely networked on the upper and lower sides of the metal nanowires, the heat generated from the metal nanowires can be more effectively dispersed on the entire surface of the substrate 10. The detailed description of each configuration of FIG. 1B is the same as FIG. 1A, and a description thereof will be omitted.

3 is a cross-sectional view of a light-transmitting composite film according to another embodiment of the present invention.

Referring to FIG. 3, a substrate 10 may be disposed. The substrate 10 may be made of a light transmissive material. For example, the substrate 10 may be an inorganic substrate such as glass, sapphire, or quartz, or may be an inorganic substrate such as PET (polyethylene terephthalate), polyethylene naphthalate (PEN), polyether sulfonate (PES), polymethyl methacrylate Or an organic material substrate such as polycarbonate (PC). However, the present invention is not limited thereto.

A metal nanowire film (20) is disposed on the substrate (10). The metal nanowire film 20 may contain a plurality of metal nanowires 21. The metal nanowires 21 may be any one selected from silver, gold, platinum, copper, and nickel.

The metal nanowires 21 may be randomly arranged in the film 20. At this time, the metal nanowires 21 may be arranged so that a part thereof overlaps with each other. That is, the metal nanowires 21 may be connected to each other.

A carbon nanotube film (30) is disposed on the metal nanowire film (20). The carbon nanotube film 30 may contain carbon nanotubes. For example, the carbon nanotubes 31 contained in the carbon nanotube film 30 may be single wall carbon nanotubes, double wall carbon nanotubes, or multiwall carbon nanotubes. However, the present invention is not limited thereto, and various known carbon nanotubes can be used.

The carbon nanotubes 31 may be connected to each other with a tight network structure. The carbon nanotubes 31 may cover the surfaces of the metal nanowires 21.

As described above, the metal nanowires 21 are connected to each other, and the carbon nanotubes 31 may exist in a form covering the surface of the metal nanowires 21.

The first electrode 50a and the second electrode 50b are disposed at both ends of the substrate 10 in which the metal nanowire film 20 and the carbon nanotube film 30 are sequentially stacked. The electrodes 50a and 50b may be made of a common electrode material such as silver, copper, nickel, chromium, or aluminum. When a voltage is applied through the electrodes 50a and 50b, a current flows into the light-transmitting composite film in which the metal nanowire film 20 and the carbon nanotube film 30 are sequentially laminated, Heat may be generated. Accordingly, the light-transmitting composite film can be used as a heat generating film.

4 is a flowchart illustrating a manufacturing process of a light-transmitting composite film according to an embodiment of the present invention.

Referring to FIG. 4, a metal nanowire film is formed on a substrate (S100).

The substrate may be made of a light transmissive material. For example, the substrate may be an inorganic substrate such as glass, sapphire, or quartz, or an inorganic substrate such as PET (polyethylene terephthalate), polyethylene naphthalate (PEN), polyether sulfonate (PES), polymethyl methacrylate (PC) or the like. However, the present invention is not limited thereto. The substrate may be removed when applied to future applications.

The metal nanowire film may be formed by coating a metal nanowire solution on the substrate. The metal nanowire solution may be an aqueous solution containing metal nanowires. At this time, the diameter of the metal nanowire may be 1 to 100 nm and the length may be 1 to 50 탆.

The viscosity of the solution can be increased by adding the thickener to the metal nanowire solution. For example, hydroxypropylmethyl cellulose (HPMC) and carboxymethyl cellulose (CMC) may be used as the above-mentioned thickener, but the present invention is not limited thereto.

The metal nanowire solution to which the thickener is added may be dispersed by ultrasonication and then coated on the substrate. Before the coating, a metal mesh may be used to remove impurities present in the metal nanowire solution. The coating can be, for example, spin coating. Thereafter, the solvent is volatilized through the drying process, and a metal nanowire film can be formed on the substrate.

A carbon nanotube film is formed on the metal nanowire film (S200).

For example, the carbon nanotube film may be formed by coating a carbon nanotube solution on the metal nanowire film. The carbon nanotube solution may be an aqueous solution containing carbon nanotubes.

The carbon nanotube solution may be subjected to ultrasonic treatment and then centrifuged. By doing so, fine-dispersed carbon particles can be precipitated and removed. After centrifugation, the supernatant can be collected.

Thereafter, the carbon nanotube solution may be coated on the metal nanowire film. The coating can be, for example, a spray coating. Thereafter, the solvent is volatilized through the drying process, and a carbon nanotube film can be formed on the metal nanowire film.

At this time, the carbon nanotubes contained in the carbon nanotube film may be connected to each other with a dense network structure to cover the surface of the metal nanowires randomly arranged in the metal nanowire film. Therefore, when a voltage is applied, carbon nanotubes can disperse heat generated by flowing a large amount of current through a metal nanowire having a low resistance. Therefore, there is an advantage that stability against heat generation of the metal nanowire and uniformity of heat generation of the substrate are improved.

Hereinafter, preferred examples will be given to facilitate understanding of the present invention. It should be understood, however, that the following examples are intended to aid in the understanding of the present invention and are not intended to limit the scope of the present invention.

Experimental Example

1. Silver Nanowire  Solution preparation

A silver nanowire solution (SNW-004a-02, N & B) containing 2 wt.% Of silver nanowires was prepared in the aqueous solution. The silver nanowire has a diameter of 40 nm and a length of 15 mu m. HPMC (hydroxy propyl methyl cellulose, Aldrich) and CMC (carboxy methyl cellulose, Aldrich) were added to increase the viscosity of the silver nanowire solution. More specifically, an aqueous solution containing 2.4 wt.% Of HPMC and an aqueous solution containing 6 wt.% Of CMC were respectively prepared in distilled water. 3.66 g of the HPMC solution was added to 4.4 g of the nanowire solution, stirred for 5 minutes, and sonicated for 5 minutes to disperse uniformly. Thereafter, 0.74 g of CMC aqueous solution was further added, and the stirring and ultrasonic treatment were repeated. Thereafter, it was charged into a vacuum chamber to remove air bubbles in the mixed solution, and the large silver nanowire particles or impurities present in the mixed solution were removed by filtration using a 500 mesh mesh.

2. Preparation of carbon nanotube solution

It was prepared SWNTs (ASP-100F, Hanwha Nanotech ^®). The single-walled carbon nanotube solution was prepared by mixing 10 mg of carbon nanotubes and 0.5 g of sodium dodecylbenzene sulfate (SDBS) in 100 ml of distilled water, treating the mixture with ultrasound (700 W, 43% power) for 30 minutes and centrifuging The finely dispersed particles were precipitated and an 80% solution of the upper layer was taken.

3. Manufacture of light transmission composite film

The glass substrate was immersed in a 3M NaOH solution for 12 hours, then washed in distilled water for 10 minutes and methanol for 5 minutes. It said cleaned substrate is 1 wt% APS in-washed in the ^{(3-Aminopropyltriethoxy silane, Aldrich ®} ) was treated for 15 minutes in an aqueous solution for 5 min in methanol and distilled water for 10 minutes, dried at 110 ℃ for 15 minutes. .

The silver nanowire solution prepared in the above step 1 was spin-coated on a glass substrate at a speed of 2000 rpm for 60 seconds, washed with distilled water for 10 minutes, and then dried at 120 ° C for 10 minutes to form a silver nanowire film. The carbon nanotube solution prepared in the above step 2 was spray coated on the silver nanowire film, washed with distilled water for 10 minutes, and dried to form a carbon nanotube film.

Comparative Example  One

The silver nanowire solution prepared through the procedure of Experimental Example 1 was spin-coated on the same glass substrate as in the above Experimental Example to form a silver nanowire film.

Comparative Example  2

The carbon nanotube solution prepared in the step 2 of the Experimental Example was spin-coated on the same glass substrate as in the Experimental Example to form a carbon nanotube film.

Comparative Example  3

The mixed solution prepared by mixing the silver nanowire solution prepared in Step 1 of the Experimental Example and the carbon nanotube solution prepared in Step 2 of the Experimental Example was spin-coated on the same glass substrate as in the experimental example, To form a composite film.

FIGS. 5A and 5B are SEM images showing the silver nanowire film of Comparative Example 1 and the carbon nanotube film of Comparative Example 2. FIG.

5A and 5B, silver nanowires of the silver nanowire film of Comparative Example 1 are randomly distributed on a glass substrate, and a space between the silver nanowires is wide (FIG. 5A). On the other hand, in the carbon nanotube film of Comparative Example 2, it was confirmed that the carbon nanotubes were arranged in a tight net shape, and the entire surface of the film was relatively uniformly covered (FIG. 5B).

6A and 6B are SEM images showing a light-transmitting composite film according to Comparative Example 3. Fig.

7A and 7B are SEM images showing a light-transmitting composite film according to an embodiment of the present invention.

6A, 6B, 7A, and 7B, in the light-transmitting composite film of Comparative Example 3, silver nanowires are randomly arranged, and carbon nanotubes are often interposed between the silver nanowires can confirm. That is, carbon nanotubes covering the surface of silver nanowires are rarely found, and carbon nanotubes are interposed in spaces between silver nanowires (FIGS. 6A and 6B).

On the other hand, in the light-transmitting composite film of the present invention, it is confirmed that the silver nanowires are randomly arranged, and the carbon nanotubes are covered with a bundled network structure on the surface of the silver nanowires (FIGS. 7A and 7B) 7b).

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Experimental Example Permeability (%) 85.7 85.7 85.5 85.7 Sheet resistance (Ω / □) 10.5 359.6 21.6 14

Table 1 shows the transmittance and sheet resistance of the light-transmitting composite film according to Comparative Example 1, Comparative Example 2, Comparative Example 3 and one embodiment of the present invention.

Referring to Table 1, the silver nanowire film of Comparative Example 1 had a transmittance of 85.7% and a sheet resistance of 10.5? / ?, the transmittance of the carbon nanotube film of Comparative Example 2 was 85.7%, and the sheet resistance was 359.6? /? The transmittance of the composite film of Comparative Example 3 is 85.5% and the sheet resistance is 21.6? / ?. On the other hand, the transmittance of the composite film of the present invention is 85.7% and the sheet resistance is 14.0? / ?. Scattering occurs when light is transmitted because the Noyer is a metal, and it can be confirmed that both films show similar transmittance in spite of the difference in density between silver nanowires and carbon nanotubes (see FIGS. 5A and 5B).

In the case of the composite film of the present invention, the transmittance is similar to that of the silver nanowire film of Comparative Example 1, the carbon nanotube film of Comparative Example 2, and the composite film of Comparative Example 3, Of the composite film of Comparative Example 3, which is lower than that of the composite film of Comparative Example 3. [

FIG. 8 is a graph showing a temperature change according to a voltage of a silver nanowire film of Comparative Example 1. FIG.

9 is a graph showing the temperature change of the carbon nanotube film of Comparative Example 2 according to the voltage.

8 and 9, when the DC voltage condition was changed and applied to the silver nanowire film of Comparative Example 1, the silver nanowire film achieved a temperature rise of about 80 DEG C at a voltage of 9V (FIG. 8) . On the other hand, in the carbon nanotube film of Comparative Example 2, when a low voltage of 25 V was applied to measure the heat generation (Fig. 9), the amount of current flowing was small and the temperature change was as low as about 10 캜. This is because the carbon nanotube film has a relatively higher resistance than the silver nanowire film.

FIGS. 10A and 10B are graphs showing temperature changes according to voltage of the composite film of Comparative Example 3 and the light-transmitting composite film according to an embodiment of the present invention.

10A and 10B, the composite film of Comparative Example 3 had a sheet resistance of 21.6? /? At a transmittance of 85.5% (FIG. 10A), whereas the composite film of the present invention had a sheet resistance of 14.0? / (Fig. 10B). As described above, the difference in sheet resistance between the composite film of Comparative Example 3 and the composite film of the present invention is due to the large contact resistance occurring at the point where the metal and the carbon nanotube are in contact with each other in the composite film of Comparative Example 3, do.

That is, since the composite film of the present invention forms a carbon nanotube film on the silver nanowire film after first forming the silver nanowire film, the resistance of the composite film is determined by the contact between the silver nanowires, The carbon nanotube film formed on the upper side has a low resistance because it does not greatly affect the resistance of the composite film due to the parallel connection of the resistors. On the other hand, since the composite film of Comparative Example 3 forms a film by mixing the silver nanowire solution and the carbon nanotube solution, the carbon nanotubes are interposed between the silver nanowires, And the resistance between the carbon nanotubes are connected in series to determine the resistance of the composite film. Therefore, the resistance of the composite film is larger than that of the composite film of the present invention. As a result, they exhibit a large sheet resistance difference at similar permeability.

Also, based on the application of a voltage of 9V, the composite film of Comparative Example 3 exhibited a temperature change of about 40 ° C (FIG. 10a), while the composite film of the present invention exhibited a temperature of about 90 ° C (Fig. 10B). This is because, as described above, since the light-transmitting composite film of the present invention has a lower sheet resistance than that of the light-transmitting composite film of Comparative Example 3, a large current can flow at the same voltage and heat generation becomes larger.

FIGS. 11A and 11B are graphs showing temperature changes with time of a silver-nanowire film of Comparative Example 1 and a light-transmitting composite film according to an embodiment of the present invention.

11A and 11B, when a voltage capable of reaching about 80 DEG C was applied for 30 minutes to measure the temperature change, the silver nanowire film of Comparative Example 1 was irradiated with a voltage of 9 V for about 8 minutes After the temperature rises to 80 캜, the temperature gradually decreases with time (Fig. 11 (A)). This is attributed to the damage of the nanowire during the exotherm. On the other hand, it can be confirmed that the temperature of the composite film of the present invention did not change with time after it was raised to a temperature of about 80 캜 by applying a voltage of 9V. It can be seen that the silver nanowires generate heat without damage (FIG. 11B). This is because the carbon nanotubes are disposed on the surface of the silver nanowires to disperse heat generated from the silver nanowires.

FIGS. 13A and 13B are SEM images illustrating the heat generation according to the voltage application of the light-transmitting composite film according to an embodiment of the present invention.

Referring to FIGS. 13A and 13B, a voltage was applied to the composite film of the present invention to measure the heat generation. As a result, it can be seen that carbon nanotubes are bundled on the locally broken silver nanowires. In this case, the carbon nanotubes connect the broken portion of the silver nanowire. As a result, the disadvantage of silver nanowires, which are susceptible to heat generation, is complemented by carbon nanotubes, which is advantageous in that the composite film acts as a heater in spite of silver nanowire damage as compared with a film made of silver nanowires alone.

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, This is possible.

10: substrate 20: metal nanowire film
21: metal nanowire 30: carbon nanotube film
31: Carbon nanotubes 40: Protective film

Claims (12)

Board;
A metal nanowire film randomly arranged on the substrate, the metal nanowire including a plurality of metal nanowires, wherein a portion of one metal nanowire is overlapped with and connected to a portion of another metal nanowire;
A carbon nanotube disposed on the metal nanowire film and having a resistance higher than that of the metal nanowire and having a thermal conductivity higher than that of the metal nanowire and connected to each other on the surface of the metal nanowire, A carbon nanotube film containing carbon nanotubes; And
A first electrode and a second electrode electrically connected to the left and right of the metal nanowire film and the carbon nanotube film, respectively,
When a voltage is applied to the first electrode and the second electrode, a current flows in a direction parallel to the surface of the metal nanowire film and the carbon nanotube film, and more current Wherein heat is generated in the metal nanowires, and the carbon nanotubes disperse the heat generated from the metal nanowires to the surroundings. delete delete The method according to claim 1,
And a carbon nanotube film disposed under the metal nanowire film. The method according to claim 1,
And a protective film disposed on the carbon nanotube film. 6. The method of claim 5,
Wherein the protective film comprises a light-transmitting polymer. The method according to claim 1,
Wherein the metal nanowire is any one of gold, silver, platinum, copper, and nickel nanowires. The method according to claim 1,
Wherein the carbon nanotube is a single-walled carbon nanotube, a double-walled carbon nanotube, or a multi-walled carbon nanotube. delete Forming a metal nanowire film randomly arranged on the substrate, the metal nanowire including metal nanowires, wherein a portion of one metal nanowire is overlapped with a portion of another metal nanowire and connected to each other;
And carbon nanotubes having a resistance higher than that of the metal nanowires and having a thermal conductivity higher than that of the metal nanowires and being connected to each other on the surface of the metal nanowires to form a network structure on the metal nanowire film To form a carbon nanotube film; And
Forming a first electrode and a second electrode electrically connected to the metal nanowire film and the carbon nanotube film, respectively, on the right and left sides,
When a voltage is applied to the first electrode and the second electrode, a current flows in a direction parallel to the surface of the metal nanowire film and the carbon nanotube film, and more current Wherein heat is generated in the metal nanowires, and the carbon nanotubes disperse heat generated from the metal nanowires around the nanowires. 11. The method of claim 10,
And forming a carbon nanotube film prior to the step of forming the metal nanowire film. 11. The method of claim 10,
The method of claim 1, further comprising forming a protective film on the carbon nanotube film after forming the carbon nanotube film on the metal nanowire film.

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