KR20150035346A - Transparent electrode and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a transparent electrode and a manufacturing method thereof. The transparent electrode is able to improve optical characteristics such as visibility by reducing the reflectivity of a metal part, improve electric characteristics with an increase in oxidation stability, and show excellent flexibility by selectively covering a mesh-patterned metal layer with a graphene oxide. The transparent electrode includes a substrate; the mesh-patterned metal layer; and a graphene oxide-covered layer.

Description

TECHNICAL FIELD [0001] The present invention relates to a transparent electrode,

The present invention relates to a transparent electrode having improved optical properties such as visibility and improved electrical characteristics due to an increase in oxidation stability, and a method for producing the transparent electrode.

The touch panel transparent electrode material has been developed based on indium tin oxide (ITO). This is made by depositing ITO on glass or film. Although the ITO transparent electrode has a low sheet resistance of less than 100 ohms and excellent optical characteristics with a transmittance of 90% or more, the performance is limited when it is applied to a large area of 10 inches or more, and there is a limit to warping And the fact that indium, which is a constituent of the material, is a scarce resource. Therefore, efforts to develop a material that can replace them have been continuing.

Up to now, metal mesh, graphene, metal oxide (ZnO), conductive polymer (PEDOT), silver nanowire (AgNW), fluorinated tin (FTO) . However, the aluminum-based metal mesh is not suitable for a large area touch screen such as a monitor requiring a sheet resistance of several tens of ohms because the sheet resistance is more than 100 ohms. When the mesh line width exceeds 5 mu m, there is a problem that it is difficult to realize a fine line width in a negative photoresist as compared with a positive photoresist due to problems such as visible visibility. Further, in the case of a metal mesh made of a copper material, there is a problem such as surface oxidation. In addition, in the case of a transparent electrode based on a metal mesh, distortion of light due to high reflectance of a patterned metal part, and deterioration of visibility may occur, which is difficult to apply as a transparent electrode. This is because the reflectance of gold (Au), silver (Ag), and copper (Cu) is 90% or more based on light in the visible light region.

In addition, although ZnO has been proposed as a representative metal oxide transparent electrode material, it is difficult to overcome the electrical resistance of several ohms of sheet resistance and has low flexibility. On the contrary, conductive polymers and silver nanowires are advantageous in terms of flexibility, but in the case of conductive polymers, sheet resistance is several hundreds of ohms, which is difficult to apply to electrostatic touch screens. Silver nanowires can realize low resistivity of tens of ohms, There is a problem that the visibility is low due to a high haze. In the case of fluorine-doped tin (FTO) in which tin is doped with fluorine without indium, it is possible to realize a low specific resistance of several ohms. However, since heat treatment at 600 ° C or more is required, it is difficult to apply to film materials and is not suitable as a transparent electrode material due to high haze .

Accordingly, it is required to develop a transparent electrode material having high transmittance comparable to ITO, excellent optical characteristics of low haze, electrical characteristics having a low specific resistance of several tens of ohms, and flexibility capable of realizing a large area touch screen.

Korean Patent Laid-Open Publication No. 2013-0033538 (published on Apr. 4, 2013)

An object of the present invention is to provide a transparent electrode having improved optical properties such as visibility and improved electrical characteristics due to an increase in oxidation stability, and also having excellent flexibility and a method for producing the transparent electrode.

In order to achieve the above object, a transparent electrode according to an embodiment of the present invention includes a substrate; A metal layer formed on the substrate and having a mesh pattern; And a coating layer of graphene oxide coated on the mesh patterned metal layer.

In the transparent electrode, the metal layer may include a transition metal selected from the group consisting of copper (Cu), nickel (Ni), iron (Fe), zinc (Zn), aluminum (Al), and molybdenum .

The metal patterned metal layer may have a mesh pattern of 1 to 10 mu m in line width and 100 to 200 mu m in line.

In addition, the mesh-patterned metal layer may have a thickness of 0.03 to 2 mu m.

The coating layer of the graphene oxide may have a line width of 1 to 5 times the pattern line width in the mesh-patterned metal layer.

A method of manufacturing a transparent electrode according to another embodiment of the present invention includes: forming a photoresist film on a substrate; Patterning the photoresist film to expose a substrate positioned below the photoresist film in a mesh pattern; Metal plating on the exposed substrate to form a mesh patterned metal layer; And forming a coating layer of graphene oxide on the mesh patterned metal layer.

In the method of manufacturing the transparent electrode, the photoresist may have a hydrophobic property such that water on the photoresist film exhibits a surface contact angle of 80 to 100 DEG.

When the contact angle contrast is defined as in Equation (1), the contact angle of the photoresist and the metal patterned metal layer may be 0.3 to 0.9.

[Equation 1]

Contact angle = (contact angle of mesh-patterned metal layer) / (contact angle of photoresist)

The metal patterned metal layer may be formed by electroless plating.

The metal patterned metal layer may have a mesh pattern of 1 to 10 mu m in line width and 100 to 200 mu m in line.

In addition, the metal patterned metal layer may have a thickness of 1/3 to 1 times the thickness of the photoresist film.

The graphene oxide may have an average particle size of 0.05 to 3 mu m.

The coating layer of the graphene oxide may be formed by dipping a mesh-patterned metal layer into a composition containing graphene oxide particles, and then adsorbing graphene oxide only on the mesh-patterned metal layer.

Other details of the embodiments of the present invention are included in the following detailed description.

The transparent electrode according to the present invention is improved in optical characteristics such as visibility by reducing the reflectance of the metal part by selectively covering the metal patterned metal part with the graphene oxide and the coating layer of the graphene oxide is formed into a mesh- It is possible to exhibit excellent flexibility by using graphene oxide which is excellent in flexibility and stretchability as a covering material.

FIG. 1 is a process diagram schematically showing a manufacturing process of a transparent electrode according to an embodiment of the present invention.
2 is a flow chart of the transparent electrode manufacturing process in the first embodiment.
3 is a scanning electron microscope (SEM) image of the patterned copper layer prepared in Example 1. Fig.
Fig. 4 is a photograph of graphene oxide observed before and after formation of a coating layer on the mesh-patterned copper layer in Example 1, wherein a) is a graphite oxide layer before formation of a coating layer, and b) to be.
5 is a photograph showing the result of observing the flexibility of the transparent electrode prepared in Example 1. Fig.

The present invention is capable of various modifications and various embodiments and is intended to illustrate and describe the specific embodiments in detail. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present invention, terms such as "comprises" or "having" are used to designate the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

A transparent electrode according to an embodiment of the present invention includes a substrate; A metal layer formed on the substrate and having a mesh pattern; And a coating layer of graphene oxide coated on the mesh patterned metal layer.

The substrate may be a transparent inorganic substrate such as glass and quartz or a transparent plastic substrate such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyether sulfone (PES), polyimide A substrate or a film, and a flexible plastic substrate or film may be preferable.

The substrate may be surface-treated with a urethane primer or the like.

In addition, the thickness of the substrate may be appropriately determined depending on the application field of the transparent electrode, but may be 50 to 200 탆, and preferably 100 to 150 탆.

On the substrate, a mesh-patterned metal layer (hereinafter simply referred to as a 'metal mesh layer') is placed.

The metal is not particularly limited as long as it is usually used for a transparent electrode. However, in order to selectively adsorb graphene oxide only on the metal mesh layer at the time of formation of the coating layer of the graphene oxide, it is preferable that the graphene oxide exhibits hydrophilicity. In consideration of this point, copper (Cu), nickel (Ni), iron (Fe), zinc (Zn), aluminum (Al) Or a transition metal such as molybdenum (Mo) may be more preferable.

In the metal mesh layer, the mesh pattern may be a pattern in which a plurality of openings are regularly or irregularly repeated, and the shape of the opening may be various shapes such as circular, triangular, rectangular, and zigzag shapes. Of these, a mesh pattern in which openings of a square are regularly formed may be preferable.

In addition, the line width or density of the mesh pattern can be adjusted in consideration of transparency, flexibility, or mechanical strength of the transparent electrode required. Specifically, it is preferable that the mesh pattern has a line width of 1 to 10 mu m and a line width of 100 to 200 mu m.

The thickness of the metal mesh layer may preferably be 0.03 to 2 탆.

A coating layer of graphene oxide is located on the metal mesh layer.

The coating layer of the graphene oxide may be formed by selectively adsorbing graphene oxide particles only on the metal mesh layer. The coating layer of the graphene oxide selectively formed only on the metal mesh layer as described above can improve the optical characteristics by reducing the reflectance of the transparent electrode by covering the metal of the mesh pattern. In addition, The stability can be improved. Further, since the coating layer of graphene oxide is excellent in flexibility and stretchability, the flexibility of the transparent electrode can be increased without deformation of the surface such as peeling and cracking of the transparent electrode.

Specifically, it is preferable that the coating layer of the graphene oxide has a line width of 1 to 5 times the mesh line width of the metal mesh layer. When the linewidth of the coating layer is less than 1 times, the effect of reducing the reflectance due to the metal not coated with the graphene oxide is insignificant, and there is a risk of oxidation in the uncoated metal portion. On the other hand, if it is more than 5 times, there is a fear that the permeability may be reduced due to overlaying on the transmissive portion without the metal portion.

It is preferable that the coating layer of the graphene oxide has a thickness of 2 to 100 nm. If the thickness of the coating layer is less than 2 nm, the effect of forming the coating layer is insignificant. If the thickness exceeds 100 nm, the effect of electrical conduction due to an increase in sheet resistance of the metal portion may be deteriorated. The graphene oxide coating layer may be a monolayer having a single layer of a graphene oxide film, a bi-layer having a two-layer structure, or a multi-layer structure having a multi-layer structure .

The transparent electrode having the above-described structure includes: forming a photoresist film on a substrate; Patterning the photoresist film to expose a substrate positioned below the photoresist film in a mesh pattern; Forming a metal mesh layer on the exposed substrate by metal plating; And forming a coating layer of graphene oxide on the metal mesh layer.

FIG. 1 is a process diagram schematically showing a manufacturing process of a transparent electrode according to an embodiment of the present invention. FIG. 1 is an illustration for illustrating the present invention, but the present invention is not limited thereto.

Hereinafter, each step will be described in detail with reference to FIG.

Step 1 is a step of forming a photoresist film on the substrate (S1).

The substrate is the same as described above,

The photoresist usable for forming the photoresist film may be a negative photoresist or a positive photoresist. Of these, a positive photoresist having excellent fine pattern forming property may be more preferable.

The photoresist film is patterned to serve as a mask in forming a metal layer thereafter, and acts as a hydrophobic group to induce a coating layer selectively formed only on a metal layer when forming a coating layer of hydrophilic graphene oxide. Accordingly, it is preferable that the photoresist has proper hydrophobicity so as to exhibit the above-mentioned effect. Specifically, it is preferable that the water on the photoresist film has a surface contact angle of 80 DEG or more, and a surface contact angle of 80 to 150 DEG The hydrophobicity may be preferably as high as the hydrophobicity. If the contact angle is less than 80 °, selective coating of the graphene oxide coating layer is not easy, and there is a possibility that the permeability may be lowered due to the entire coating on the transmissive portion without the metal portion and the metal portion.

When the contact angle contrast is defined as in Equation (1), the contact angle of the photoresist and the metal patterned metal layer may preferably be 0.3 to 0.9.

[Equation 1]

Contact angle = (contact angle of mesh-patterned metal layer) / (contact angle of photoresist)

The hydrophobicity of the photoresist may be controlled by controlling the hydrophobicity and hydrophilicity of the photoresist-forming material or the amount thereof, or by adding alcohols such as alcohols, acetone, and acetonitrile, which are low in surface tension and capable of water- , And can be controlled by adding a hydrophobic substance such as BYK®DYNWET® or BYK-3440, a product of BYK Co., Ltd., a surface tension reducer. As another method, a method of surface-treating a photoresist film with a reactive gas containing fluorine (F) in an atmospheric pressure plasma atmosphere or using a hydrophobic compound such as hexamethyldisilazane (HMDS) may be used have.

The formation of the photoresist film on the substrate may be performed by applying the photoresist directly on the substrate, followed by drying, or by laminating the photoresist film on the substrate and selectively heat-treating or pressing the photoresist film. When a photoresist film is formed by coating, it can be carried out according to a conventional slurry coating method. Specific examples thereof include spin coating, bar coating, slit die coating, roll coating and the like, but are not limited thereto. It is also preferable that the photoresist is applied so that the thickness of the photoresist film after drying becomes 0.1 to 2 占 퐉.

The drying process after application of the photoresist may be performed at 50 to 200 ° C, preferably 70 to 130 ° C.

Step 2 is a step of patterning the photoresist film by lithography so that the substrate positioned below the photoresist film formed on the substrate is exposed as a mesh pattern (S2).

Specifically, after a mask having a predetermined pattern is placed on the photoresist film, a part of the photolithography is removed through a photolithography process including exposure and development to form a photolithography pattern, and at the same time, To expose the substrate located below the photoresist film.

The patterning of the photoresist film may be patterned in consideration of the fine metal wiring, and then the metal layer to be formed may be patterned to have the mesh pattern. More specifically, it may be more preferable that the substrate is patterned to expose the substrate in a mesh pattern having a line width of 1 to 10 mu m and a line length of 100 to 200 mu m.

The patterned photoresist includes a channel formed by a mesh pattern. The channel formed between the photoresist acts as a capillary in the subsequent metal layer formation so that a water-soluble metal plating solution can selectively form a plating area in the channel.

The exposure conditions such as the exposure atmosphere or the exposure dose in the exposure process for patterning the photoresist film are not particularly limited. However, in order to ensure that the transparent electrode has a sufficient transmittance, it may be preferable to irradiate light with a wavelength of 350 to 400 nm .

The developing process may be performed by immersing the developer in a basic solution such as tetramethyl ammonium hydroxide (TMAH). At this time, when the developing solution temperature is 20 to 40 ° C, the efficiency and speed of the developing process are increased So that it can be preferable.

Step 3 is a step of forming a metal layer on the substrate exposed as a mesh pattern between the photoresist patterns as a result of the step 2 (S3).

At this time, the photoresist pattern serves as a mask, and the metal layer is formed only on the substrate exposed between the photoresist patterns.

The metal mesh layer may be formed by an electroless or electrolytic plating method using a metal plating liquid such as copper (Cu), nickel (Ni), iron (Fe), zinc (Zn), aluminum (Al), molybdenum Or may be formed by CVD or sputtering of the metal element. In particular, damage to the substrate, which may occur in comparison with CVD or sputtering, can be minimized particularly for the film substrate material, and the metal It may be preferable to be formed by electroless plating for reasons such as to reduce unnecessary use of the element material and to enable a rapid processing time. The electroless plating may be performed according to a conventional electrolytic plating method.

The metal mesh layer formed on the substrate exposed between the photoresist patterns has a mesh pattern depending on the shape of the exposed substrate. In this case, the line width or density of the mesh pattern of the metal mesh layer can be adjusted in consideration of the required transparency, flexibility, or mechanical strength of the transparent electrode. Specifically, the mesh can have a mesh width of 1 to 10 탆, Pattern.

The metal mesh layer may preferably have a thickness of 1/3 to 1 times the thickness of the photoresist film in consideration of transparency, flexibility, or mechanical strength of the transparent electrode.

When the metal mesh layer is formed through electroless plating, a cleaning process for removing the remaining plating liquid may be further performed. The washing process may be carried out according to a conventional method. Specifically, it may be preferable to conduct the washing process so as to have a pH of 4 to 7 through distilled water.

Step 4 is a step of forming a coating layer of graphene oxide on the metal mesh layer formed in step 3 (S4).

The coating layer of the graphene oxide may be formed by applying a composition for forming a coating layer of graphene oxide on the metal mesh layer and drying the coating layer or by dipping and drying the substrate on which the metal mesh layer is formed . When a coating layer of graphene oxide is formed by an immersion process, the immersion process may be performed for 0.5 to 12 hours, preferably for 2 to 5 hours.

The coating layer forming composition of graphene oxide may be prepared by dispersing graphene oxide in water or an organic solvent.

The graphene oxide may be commercially available or may be prepared by treating the undifferentiated graphite with a modified hummer`s method (Chem.Mater. 1999. 11. 771) by a conventional milling process such as ball milling .

In addition, the graphene oxide may have an average particle size of 0.05 to 3 탆, preferably 0.1 to 0.5 탆. If the average particle size of the graphene oxide is out of the above range, if it is excessively large, the coating may exceed the pattern line width of the metal layer, which is not preferable.

The graphene oxide may be contained in an amount of 0.1 to 2% by weight based on the total weight of the coating layer-forming composition of graphene oxide.

Examples of the organic solvent include acetone, methyl ethyl ketone, methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol, ethylene glycol, polyethylene glycol, tetrahydrofuran, dimethylformamide, dimethylacetamide, N- Methylene-2-pyrrolidone, hexane, cyclohexanone, toluene, chloroform, distilled water, dichlorobenzene, dimethylbenzene, trimethylbenzene, pyridine, methylnaphthalene, nitromethane, acrylonitrile, octadecylamine, , Or methylene chloride.

The composition for forming a coating layer of the graphene oxide may further contain 0.01 to 0.5% by weight of a thickening agent such as hydroxymethyl cellulose (HPMC).

In order to selectively form a coating layer of graphene oxide only on the metal mesh layer, it is preferable to control the hydrophilicity or hydrophobicity of the composition for forming a coating layer of graphene oxide. Specifically, in consideration of the contact angle of the photoresist and the metal layer, it may be preferable to impart hydrophilic or hydrophobic properties to the coating layer forming composition.

When the substrate having the metal mesh layer formed thereon is immersed in the composition for forming a coat layer of graphene oxide as described above, stripping is omitted in the photolithography process, so that hydrophobicity of the photoresist surface and hydrophilicity of the metal mesh layer are respectively present. Due to the hydrophilicity and hydrophobicity of each part, the hydrophilic graphene oxide is selectively adsorbed only on the metal mesh layer. The adsorption phenomenon of graphene oxide is advantageous in transition metal, and is more effective in copper, nickel, iron and the like.

The coating range of the graphene oxide is preferably 1 to 5 times the line width of the metal mesh layer. If it is less than 1 time, the effect of reducing the reflectance due to the metal not coated with the graphene oxide is insignificant, and there is a risk of oxidation in the uncoated metal part. On the other hand, if it is more than 5 times, there is a fear of reduction of permeability due to excessive coating of the transmissive portion without the metal portion, which is not preferable.

After the coating layer of the graphene oxide is formed, a cleaning process and a hot air drying process may be further performed.

The washing process may be performed using distilled water or a mixed solvent of distilled water and alcohol (for example, ethanol, etc.), and the hot air drying process may be performed by supplying hot air at 80 to 150 ° C.

After the coating layer of the graphene oxide is formed, a step of removing the photoresist pattern by a conventional method such as an atmospheric plasma treatment may be further performed.

Since the method of forming a transparent electrode as described above forms a mesh patterned metal layer through photolithography, cracks are generated in the photoresist film through conventional heat treatment or the like, and compared with forming a mesh pattern of the metal layer using the cracks, It is easy to control the pattern such as the interval and the density, and the uniformity of the pattern can be increased.

In addition, since the transparent electrode prepared according to the above-described method is selectively coated with graphene oxide only on the mesh-patterned metal portion, the reflectance of the metal portion can be reduced and the optical characteristics related to visibility can be improved. Further, since the coating layer of the graphene oxide serves as a protective layer for suppressing the oxidation of the patterned metal, there is almost no change in electric resistance. In addition, since the graphene oxide excellent in flexibility and stretchability is used as a covering material, the flexibility of the transparent electrode is also excellent.

Accordingly, the transparent electrode according to the present invention can be used not only as a transparent electrode that can use copper or nickel wiring, but also as a transparent conductive film; FPCB (Flexible printed circuit board); An RFID (Radio Frequency Identification) antenna; Optical devices such as solar cells and light emitting diodes; A display element such as a liquid crystal display element or a plasma display element; Heat sink; Electromagnetic wave shielding agents; An anti-static sensor, and the like.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Example  One

Fig. 2 is a flowchart showing a process for manufacturing a transparent electrode according to the first embodiment, and will be described with reference to Fig.

In this embodiment, a polyethylene terephthalate (PET) film treated with a urethane primer having a thickness of 100 탆 was used. In the photoresist (PR) application step (S10), a positive photoresist was applied to the PET film, followed by heat treatment at 100 占 폚 to 30 占 폚 and drying. Then, a mesh patterning process of a line width of 10 mu m and a line spacing of 200 mu m was carried out through a photolithography process. Specifically, the exposure step (S11) was performed by irradiating a PET film on which the positive photoresist film was formed with light having a wavelength of 400 nm for 2 seconds. In the developing step (S12), the exposed film was immersed in TMAH at 30 占 占 폚. Subsequently, the electroless plating step (S13) was performed on the PET film on which the photoresist film was patterned, using a copper plating solution. At this time, since the photoresist film covering the PET film serves as a mask, copper is plated only on the PET film exposed between the photoresist film patterns. The plating solution remaining in addition to the PET film was removed and a cleaning step (S14) was performed using distilled water so that the pH was 4 to 7, thereby forming a copper metal layer having a mesh pattern. The sheet resistance of the copper layer of the formed mesh pattern was 21? / Sq.

Next, graphite (manufactured by Bay Carbon Co., Ltd.) was finely pulverized by ball milling to have a mean particle size of 1 탆 and treated according to a modified hummer`s method (Chem.Mater. 1999. 11. 771) Oxide. The prepared graphene oxide powder was dispersed in water in an amount of 1 wt%, and 0.2 wt% of HPMC was added thereto to prepare a composition for forming a coat layer of graphene oxide. The composition for forming a coating layer of the graphene oxide was immersed in a PET film containing a copper metal layer of the mesh pattern prepared above for 2 hours to form a coating layer of graphene oxide (S15). Thereafter, a washing step (S16) was performed with a mixed solution of distilled water and ethanol mixed at a volume ratio of 1: 1, and a hot air drying step (S17) at 80 to 150 ° C was carried out. As a result, a PET film in which only the mesh-patterned copper layer was selectively coated with graphene oxide was prepared as a transparent electrode.

Fig. 3 is a scanning electron microscope photograph of the patterned copper layer produced in Example 1. Fig.

As shown in Fig. 3, it can be confirmed that a mesh pattern having a line width of 10 mu m and a line-to-line spacing of 200 mu m is formed.

4 is a photograph of the copper layer of the mesh pattern formed in Example 1 before and after the formation of the coating layer of the graphene oxide.

As shown in Fig. 4, the composition for forming a coating layer of graphene oxide showed a bright copper color by the copper layer (Fig. 4 (a)) before dipping, while it showed a dark brown color after immersion (Fig. 4 (b) Reference). This color change can be confirmed by the fact that graphene oxide is coated on the copper layer.

In addition, the coating layer of the graphene oxide thus formed can reduce the reflectance and improve the optical characteristics. In fact, the reflectance of the clean copper layer surface before the formation of the coating layer of graphene oxide was 91%, but after coating the coating layer of graphene oxide, the reflectance decreased sharply to 9%.

Further, the electrical resistance change of the graphene-coated metal layer prepared above can be confirmed by a resistance change rate measured after storage at room temperature (25 ° C) for one month.

The resistance change rate after storage for 1 month at room temperature was less than 2%. From these experimental results, it can be confirmed that the formation of the coating layer of the graphene oxide on the copper layer acts as an oxidation preventing film in addition to the improvement of the optical characteristics.

5 is a photograph showing the result of observing the flexibility of the graphene-coated copper pattern film prepared in Example 1. Fig.

As shown in Fig. 5, due to the characteristics of graphene oxide, which is excellent in flexibility and stretchability, no distortion on the surface such as peeling or cracking was observed even when the graphene-coated copper pattern film was warped.

The metal portion exhibits relatively hydrophilic property and the photoresist film exhibits relatively hydrophobic property. Accordingly, graphene oxide can be coated only on the metal mesh layer using the hydrophobic and hydrophilic properties of the photoresist film and the metal layer. Referring to FIG. 4 and FIG. 5, it can be confirmed that only graphene oxide is coated on the metal mesh layer using the above properties.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit of the invention as set forth in the appended claims. The present invention can be variously modified and changed by those skilled in the art, and it is also within the scope of the present invention.

100: substrate 200: photoresist film
300: metal layer 400: coating layer of graphene oxide

Claims (13)

Board;
A metal layer formed on the substrate and having a mesh pattern; And
The coating layer of the graphene oxide coated on the mesh patterned metal layer
. The method according to claim 1,
Wherein the mesh patterned metal layer comprises a transition metal selected from the group consisting of copper (Cu), nickel (Ni), iron (Fe), zinc (Zn), aluminum (Al), and molybdenum Transparent electrode. The method according to claim 1,
Wherein the mesh-patterned metal layer has a mesh pattern of 1 to 10 mu m in line width and 100 to 200 mu m in line. The method according to claim 1,
Wherein the mesh patterned metal layer has a thickness of 0.03 to 2 占 퐉. The method according to claim 1,
Wherein the coating layer of the graphene oxide has a line width of 1 to 5 times the mesh line width in the mesh-patterned metal layer. Forming a photoresist film on the substrate;
Patterning the photoresist film to expose a substrate positioned below the photoresist film in a mesh pattern;
Metal plating is performed on the exposed substrate to form a mesh-patterned metal layer; And
Forming a coating layer of graphene oxide on the mesh patterned metal layer
And forming a transparent electrode on the transparent electrode. The method according to claim 6,
Wherein the photoresist has a hydrophobic property such that the water on the photoresist film exhibits a surface contact angle of 80 to 100 DEG. The method according to claim 6,
Wherein the contact angle contrast of the photoresist and the metal patterned metal layer is 0.3 to 0.9 when defining the contact angle contrast as in Equation 1 below:
[Equation 1]
Contact angle = (contact angle of mesh-patterned metal layer) / (contact angle of photoresist) The method according to claim 6,
Wherein the mesh-patterned metal layer has a mesh pattern of 1 to 10 mu m in line width and 100 to 200 mu m in line. The method according to claim 6,
Wherein the mesh-patterned metal layer is formed by electroless plating. The method according to claim 6,
Wherein the mesh-patterned metal layer has a thickness of 1/3 to 1 times the thickness of the photoresist film. The method according to claim 6,
Wherein the graphene oxide has an average particle size of from 0.05 to 3 占 퐉. The method according to claim 6,
Wherein the coating layer of graphene oxide is formed by dipping a mesh patterned metal layer in a composition comprising graphene oxide particles and then adsorbing graphene oxide only on the mesh patterned metal layer.

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