KR101995096B1 - Transparent electrode using belt-shaped metal line embedded colorless transparent polyimide for OLED Display and process for manufacturing the same - Google Patents

Abstract

The present invention relates to a highly heat-resistant, flexible transparent electrode having a random arrangement or a metal nano-belt arranged in a specific direction, or a metal mesh electrode in the form of a micro-belt or grid embedded in a colorless transparent transparent polyimide substrate, . The metal nano-belt, micro-belt, or grid-shaped metal wire is manufactured by using polymer nanofibers produced by electrospinning or electrohydraulic printing apparatus as an etch mask, and thus manufacturing without an expensive photolithography process There are advantages. In particular, since metal electrode lines are embedded on one side of a completely transparent polyimide substrate, they have a smooth surface flatness and can be applied to a flexible OLED display substrate. Since it is a polyimide-based substrate, it can also be used as a substrate for a solar cell or a display requiring a high-temperature process.

Description

 BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a polyimide transparent electrode for a flexible OLED display having a belt-shaped metal electrode line and a method of manufacturing the transparent electrode using a transparent electrode,

TECHNICAL FIELD The present invention relates to a highly heat-resistant flexible polyimide-based transparent electrode having a flat surface structure by incorporating a metal electrode wire (nano belt or micro belt) of a belt-like shape constituting a transparent electrode in a colorless transparent flexible polyimide substrate, . More specifically, a metal thin film layer is formed on a glass substrate, a polymeric fiber is selectively coated on the metal thin film layer to use as an etching protection pattern, a belt-shaped metal electrode wire obtained through an etching process and a polymer fiber removing process is formed as a transparent polyimide film High conductivity, high refractive index flexible polyimide transparent electrode, which has a high thermal, mechanical and chemical stability and a uniform surface flatness.

OLED (Organic Light Emitting Diode) has attracted a great deal of attention as a next-generation display as the LCD (Liquid Crystal Display) TV market has entered a mature stage in 2010. In particular, AMOLED (Active Matrix OLED) has a mechanism of directly emitting light by using organic materials, which is considered to be suitable for a flexible display market in the future.

Therefore, in recent electronics industry, efforts are being made to realize flexible display by combining substrate technology, transistor technology, display mode technology, process technology, and material technology. Currently, transparent electrodes are used for electrode materials such as solar cells, touch panels, and displays, electromagnetic wave shielding films for cathode ray tubes (CRT), plasma display panels (PDP), and static electricity generation, As a flexible device, it is subject to a great limitation in applications. Therefore, for application as a next-generation transparent electrode, the flexibility of the electrode and the substrate must be secured. In order to realize this, electrodes such as graphene, carbon nanotube, metal nanowire, and metal mesh are proposed as promising materials. In the case of substrates, flexible and flexible organic materials such as plastic are mainly used.

In the case of metal nanowires, they are mainly made by a solution process, and a wire having a high aspect ratio can be easily produced, and thus various applications have been made. In the case of a metal mesh, the metal mesh can be designed and formed by using processes such as vacuum deposition, sputtering, ion plating, chemical vapor deposition, inkjet printing, screen printing, and the like. Korean Patent Publication No. 10-1266985 discloses a technique for manufacturing a touch screen panel transparent electrode using an electrohydrodynamic ink jet method. The electrohydrodynamic patterning method is known as a technique for manufacturing a micro-level metal mesh using relatively low-cost equipment and is expected to be widely used as a new concept metal mesh manufacturing technique.

A lithography process using a photoresist (PR) as a mask has a high technological power in forming a fine pattern and is currently used in fields requiring a semiconductor industry and various fine patterning technologies. However, the above process has a disadvantage in that equipment and mask manufacturing cost are expensive and the process is complicated.

For this reason, it is possible to manufacture electrodes using roll-to-roll, gravure, and ink-jet printing processes in an industry in which relatively low patterning technology is required compared to a semiconductor industry such as a touch panel. However, most patterning processes still suffer from low cost competitiveness and complex process steps. Recently, patterning techniques using low cost materials and processes such as patterning using grain boundaries, patterning using electrospinning method, and electrohydrodynamic jet printing method have been studied.

Electrospinning is a process capable of producing nanofibers through an electrically charged polymer solution and a jet of a melt. Such electrospinning technology is inexpensive equipment, and it is possible to easily manufacture nanofibers by using all the polymer materials which can be melted and mixed in the solvent, and it is possible to control the shape and size of the nanofibers, so that it is applicable to various application fields . However, in the electrospinning process, a random arrangement of fibers can be easily produced, but it is difficult to obtain a patterned pattern of the desired shape.

Electrohydrodynamics printing is similar to electrospinning, and is a method of ejecting fine droplets using an electric field. When a uniform electric field is generated between the nozzle and the substrate, the charged ink moves from the nozzle end to the substrate by the electrostatic force. At this time, at the nozzle end, the meniscus is maintained in a conical Taylor cone shape, Various types of discharging are performed depending on the electrostatic force magnitude. Electrohydraulic printing liquid droplets can be formed in nano and micro size at the end of Taylor cone, enabling to realize high resolution pattern of nano size and patterning in desired shape unlike electrospinning. Technology.

The colorless transparent flexible polyimide film is a polymer film having chemical resistance, heat resistance and electrical insulation properties by preparing a polyamic acid solution as a precursor solution of polyimide, coating it, and subjecting it to heat treatment for imidization at a temperature of about 200 ° C . The polyamic acid solution may be prepared by polymerizing an aromatic diamine or an aromatic diisocyanate solution with an aromatic dianhydride. Currently polyimide films are widely used in the fields of insulating films, electrode protection films, flexible device wiring boards and the like due to their flexible and flexible properties and their excellent insulating properties and thermal resistance which can withstand temperatures of around 300 ° C.

However, the polyimide film has a large disadvantage that the yellow index of the light transmittance is high because the π-π electron transition occurs in the aromatic ring molecule existing in the imide chain, and the color becomes brown and yellow. In order to solve such a problem, Korean Patent Laid-Open Publication Nos. 10-2003-0009437 and 10-2013-0110589 disclose a process for producing a π-conjugated diene polymer by changing the molecular structure of a diimine and a dianhydride, which are polyimide monomers, discloses a technique for producing a colorless, transparent and flexible polyimide by decreasing? transference.

Surface roughness is very important for flexible transparent electrodes made of various materials to be used in devices such as displays, solar cells, and touch screens. If the surface is not uniform, electrical shorting may occur at the step and the interfacial characteristics between materials may be greatly degraded, which may have a large effect on the device. Therefore, the development of a transparent electrode having both a heat resistance characteristic and a high refractive index characteristic, which is transparent, smooth, smooth, and able to withstand a high temperature process, is also required for the application of flexible solar cells and OLED displays.

It is an object of the present invention to provide a transparent electrode having excellent surface flatness, flexibility, oxidation resistance and heat resistance by incorporating a belt-shaped metal wire into a colorless transparent flexible polyimide substrate which can withstand high temperatures by applying a low- And a manufacturing method thereof.

It is another object of the present invention to provide an electrohydrodynamic deposition (EHD) or electrohydrodynamic deposition (EHD) process without complicated process steps such as photoresist coating, exposure, and development required for expensive photolithography In order to apply low-cost polymer fibers as an etching mask by using a printing method, it is necessary to pattern directly on the metal thin film layer at high speed, etch the metal thin film not covered with the polymer fibers, and remove the polymer fibers And a method of manufacturing a transparent polyimide electrode having a belt-shaped metal wire embedded therein at a high speed and a large area.

It is another object of the present invention to provide a transparent polyimide substrate and a method of manufacturing the same, which can solve the copper etching problem that may occur when a copper wire electrode is embedded in a polyimide substrate, And the copper layer is prevented by introducing a protective layer at the interface between the copper electrode and the copper wire electrode, thereby improving the electrical stability of the electrode.

It is another object of the present invention to provide a conductive polyimide substrate which is further provided with a conductive thin film on an upper layer of a metal wire electrode (random shape or mesh shape) And to provide a process for manufacturing a transparent electrode having high heat resistance.

It is another object of the present invention to provide a method of controlling the width and interval of a metal wire electrode in a belt shape by controlling the diameter of a polymer fiber obtained by electrospinning or electrohydrodynamic deposition (EHD printing) Method.

In an embodiment of the present invention, the electrode layer may be a randomly oriented metal line, or may be a grid-like mesh or a grid-like mesh, in which the electrode layer constituting the transparent electrode is embedded in one side of the flexible transparent substrate, Color transparent polyimide is used as the transparent transparent substrate. When the electrode layer is embedded in the substrate, the protective layer is included at the interface between the electrode and the substrate, thereby preventing the metal electrode from being etched by the transparent polyimide precursor solution, The conductivity of the transparent polyimide substrate is maintained at a high level, and a transparent polyimide substrate having uniform flatness is provided.

A method of manufacturing a transparent polyimide substrate having a belt-shaped metal wire embedded therein, the method comprising the steps of: (a) depositing a metal thin film layer on a glass substrate; (b) forming a grid-shaped polymeric fiber mask on the metal thin film layer by using electrospinning or electrohydrostatic printing processes; (c) swelling the polymer nanofiber mask to increase adhesion between the polymeric fiber mask and the metal foil layer; (d) etching the metal thin film layer and removing the polymeric fiber mask; (e) coating a protective layer on the randomly arranged belt-shaped metal wire or grid-shaped metal wire electrode obtained through the etching; (f) coating a polyamic acid solution, which is a precursor solution of polyimide, on the metal electrode layer including the protective layer formed on the glass substrate; (g) heat-treating the polyamic acid solution to produce a transparent transparent electrode having a metal electrode layer including a protective layer embedded in one surface of a transparent polyimide substrate; (h) separating the transparent polyimide substrate having the metal wire or grid-shaped metal wire electrode arranged in the disorderly arranged belt shape from the glass substrate; (i) coating a conductive nano- or micro-belt-added conductive film on a transparent polyimide substrate having a belt-shaped metal wire separated from the glass substrate.

The method of depositing the metal thin film layer on the upper surface of the glass substrate in the step (a) may be a DC or RF sputtering method, a pulsed laser deposition (PLD) method, a thermal evaporation method, an E-beam evaporation method, Chemical vapor deposition (CVD), or atomic layer deposition (CVD). The metal electrode constituting the metal thin film layer is not limited to a specific metal if it is a metal having high conductivity, and Ag, Cu, Ni, etc. may be preferably used.

In step (a), in order to improve adhesion properties between the glass and the metal thin film layer before depositing the metal thin film, gold, silver, titanium, chromium, nickel, platinum ), Or one of plasma, ozone ultraviolet treatment.

In the step (b), the polymer forming the polymeric fiber mask is not soluble in water. The polyacrylonitrile (PAN), polyvinylacetate (PVAc), polymethylmethacrylate (PMMA) , Polymethylmethacrylate, polystyrene (PS), polyvinylchloride (PVC), and polycarbonate (PC). The polymer nanofiber mask may be formed by an electrospinning method or an electrohydrodynamic printing method Can be used to form disordered arrangement or aligned nanofibers in the form of a grid.

In order to improve the adhesion between the polymer nanofiber mask and the metal thin film layer, a solvent capable of swelling a polymer mask, such as acetone, ethanol, N, N-dimethyl One or more of the following compounds may be used: at least one of formamide, dimethyformamide, N-methyl-2-pyrrolidone, dimethylaceteamide, tetrahydrofuran, You can choose.

In the step (d), one of a dry etching method and a wet etching method is selected and etched to etch a portion of the metal thin film not protected by the polymer nanofiber mask, and the dry etching method includes ion beam etching, Plasma etching, and high-temperature chlorine gas etching. In the wet etching method, when the interconnection interval of the polymer nanofiber mask is as wide as 5 μm or more and the thickness of the polymer nanofiber is 1 μm or more, distilled water-FeCl ₃ , distilled water - At least one of hydrochloric acid-FeCl ₃ , distilled water-nitric acid, distilled water-nitric acid-silver nitrate, distilled water-ammonium persulfate-hydrochloric acid, distilled water-copper ammonium chloride-ammonia water solution can be selected.

In the step (e), in order to protect the disorderly arranged metal line or grid-shaped metal line electrode layer obtained through etching from the polyamic acid solution as the precursor solution of the transparent polyimide substrate, a metal, ceramic, Selectively forming;

The metal and ceramic protective layers may be formed by any suitable method, such as DC or RF sputtering, Pulsed Laser Deposition (PLD), thermal evaporation, E-beam evaporation, Chemical Vapor Deposition, Atomic Layer Deposition);

The polymer protective layer may be formed by coating a solution of polyarylamine hydrochloride having a concentration of 1 wt% to 10 wt% at room temperature by any one of a spin coating method, a printing method, a dipping coating method and a spraying method Can be used.

In step (f), an amine monomer and an anhydride monomer are required to synthesize a precursor solution (polyamic acid) for forming a colorless transparent polyimide which is not a conventional yellowish polyimide. Wherein the amine monomer is selected from the group consisting of 3,3'-bis (4-aminophenoxy) biphenyl, 3-aminophenoxy benzene, p-BAPB, 2,2-bis (4-aminophenyl ), hexafluoropropane (m-BAPS), ammonium persulfate (APS), BAPF (9-Fluorenylidene) dianiline), p-BAPS (para-amino-bis metabisaminophenoxy diphenyl sulfone), BAMF 2,2'-bis (3-amino-4-methylphenyl) hexafluoropropane) and TFB (2,2'-bis (trifluoromethyl) benzidine);

Examples of the anhydride monomer include 4,4'-oxydiphthalic dianhydride (PMDA), pyromellitic dianhydride (PMDA), 3,3 ', 4,4'-diphenylsulfonetetracarboxylic dianhydride (BPDA), 4'- biphenyl tetracarboxylic acid dianhydride, (4,4 '- (4,4'-Benzophenonetetracarboxylic Dianhydride), CBDA (1, 4' , 2,3,4-cyclobutanetetracaroxylic dianhydride), and CHDA (1,4-cyclohexanedicarboxylic acid).

In the step (g), the polyamic acid solution is heat-treated at a temperature of 200 to 300 ° C to produce a transparent polyimide substrate having a metal electrode layer containing a protective layer.

In the step (h), in order to separate the transparent polyimide substrate having the metal wire or the grid-shaped metal wire electrode arranged in an uncontrolled manner from the glass substrate, the transparent polyimide substrate is immersed in water or laser- The mid substrate can be separated.

The inorganic material used as the electrode oxidation protective film having conductivity in the step (i) may include at least one of Al, Ga-doped ZnO, and ITO.

According to the present invention, a metal mesh electrode in the form of a metal nano, micro-belt, or grid is embedded in a colorless transparent flexible polyimide substrate that is not in a grid form (when having a random arrangement or aligned in a specific direction) The heat-resistant transparent electrode can dramatically lower the time and economic effort by manufacturing the polymer mask with a simple and low-cost process. In addition, it can be used in many industries that have higher temperature than solar cell and display industry by incorporating electrodes in a polyimide substrate having high heat resistance and high permeability and flexibility.

In addition, the carboxylic acid contained in the polyamic acid structure, which is a precursor of colorless transparent polyimide, can reduce the performance of the electrode by etching a metal electrode which is easily etched in an acid such as copper. To prevent this, the use of a metal electrode etch protection layer such as PAH or a ceramic thin film has opened the possibility of manufacturing a low-cost, high-performance metal electrode.

FIG. 1 is a cross-sectional schematic view of a high-temperature-resistant transparent electrode in which a metal electrode (nano, micro-metal belt or mesh) is embedded in a transparent polyimide substrate according to an embodiment.
FIG. 2 is a cross-sectional view of a metal mesh electrode having a metal nano, micro-belt, or grid shape, which is not in a grid form (in a random arrangement or in a predetermined direction only) FIG. 2 is a schematic plan view of a highly heat-resistant transparent electrode.
FIG. 3 is a flowchart showing a manufacturing process of a highly heat-resistant transparent electrode in which a metal electrode layer (metal nano, micro-belt or grid-shaped metal mesh electrode, not a grid electrode) is embedded in a colorless transparent polyimide substrate according to an embodiment.
4 is a scanning electron microscope sectional photograph of a metal thin film sacrificial layer deposited on a glass substrate according to an embodiment.
FIG. 5 is an optical microscope photograph of a PVAc polymer mask formed by an electrospinning process in a metal nano-or micro-belt, not in the form of a grid, according to an embodiment.
FIG. 6 is a scanning electron microscope photograph of a PVAc polymer mask formed by a electrospinning process in a metal nano-or micro-belt, not in the form of a grid, according to an embodiment.
FIG. 7 is an optical microscope photograph of a PAN mask patterned with a grid-shaped mesh mask by an electrohydrodynamic jet deposition process according to an embodiment.
8 is an optical microscope photograph of a PVAc polymer mask formed by an electrospinning process annealed in an organic solvent according to an embodiment.
Figure 9 is a scanning electron micrograph of a PVAc polymer mask formed by an electrospinning process annealed in an organic solvent according to an embodiment.
10 is an optical microscope image of a PAN mesh mask formed by an electrohydrodynamic jet deposition process according to an embodiment, annealed in an organic solvent.
Figure 11 is an optical micrograph of a metal nano- or micro-belt metal electrode with a random arrangement (not in the form of a grid) formed on a glass substrate according to an embodiment.
12 is a scanning electron microscope (SEM) surface photograph of a metal nano-or micro-belt metal electrode with a random arrangement (not in the form of a grid) formed on a glass substrate according to an embodiment. The nano belt is the upper picture, and the micro picture is the lower picture.
13 is an optical microscope photograph of a grid-shaped metal mesh electrode formed on a glass substrate according to an embodiment.
14 is a microscope showing the degree of metal etching by a polyamic acid depending on the presence or absence of a protective layer on a thin metal (for example, copper) electrode layer according to an embodiment.
15 is a scanning electron microscope (SEM) surface photograph of a transparent transparent electrode in which a metal nano-or micro-belt electrode having a random arrangement according to an embodiment is embedded in a transparent polyimide substrate.
16 is a scanning electron microscope (SEM) surface photograph of a transparent transparent electrode in which a metal mesh electrode is embedded in a transparent polyimide substrate according to an embodiment.
17 is a tilted scanning electron microscope cross-sectional photograph of a transparent electrode before and after the metal belt electrode is embedded in the transparent polyimide substrate according to the embodiment. The upper photograph is a photograph before it is embedded in the transparent polyimide substrate, and the lower photograph is a photograph after the electrode is embedded in the transparent polyimide substrate.
18 is a scanning electron microscope sectional photograph of a transparent transparent electrode before and after the metal mesh electrode layer is embedded in the transparent polyimide substrate according to the embodiment. The upper photograph is a photograph before the electrode is embedded in the transparent polyimide substrate, and the lower photograph is the image after the electrode is embedded in the transparent polyimide substrate.
19 is a scanning electron micrograph showing the thickness of a transparent electrode in which a metal mesh electrode is embedded in a transparent polyimide substrate according to an embodiment.
Fig. 20 shows an optical microscope photograph according to the embodiment, in which the metal mesh electrodes are embedded in the transparent polyimide substrate and are spaced apart from each other by the interval between the electrode wirings.
21 is a scanning electron microscope sectional photograph of a high heat-resistant transparent electrode in which a metal electrode layer is embedded in a transparent polyimide substrate according to an embodiment.
22 is a scanning electron micrograph of a transparent electrode of a metal mesh electrode non-integrated transparent polyimide substrate according to a comparative example.
FIG. 23 is a table showing the sheet resistance and transmittance of a metal-copper (niobium) non-grid type non-grid type electrode fabricated on the basis of the embodiment, and a high heat-resistant transparent electrode integrated with a transparent polyimide substrate.
FIG. 24 is a table showing sheet resistance and transmittance of a transparent electrode of a metal (copper) mesh fabricated on the basis of an embodiment, which is incorporated in a transparent polyimide substrate and integrated with a high heat-resistant transparent electrode.

The present invention relates to a transparent electrode and a flexible transparent substrate integrated with an electrode layer constituting a transparent electrode, and a metal nano, micro-belt or grid-like metal mesh which is not in the form of a grid having high heat resistance is embedded in a colorless transparent polyimide substrate, Electrode, and a method for producing the same, and the manufacturing method is described in detail from Examples 1, 2, 3, 4, 5, 6, and 7 in detail. In Comparative Example 1, a metal mesh electrode non-integral transparent polyimide transparent electrode was manufactured and the difference from the present invention was emphasized structurally.

1 is a schematic cross-sectional view of a highly heat-resistant transparent electrode in which a metal electrode layer (metal nano, micro-belt, or metal mesh) is embedded in a transparent polyimide substrate according to an embodiment of the present invention. As shown in FIG. 1, the metal electrode layer-integrated transparent electrode 100 uses a colorless and transparent flexible polyimide 110 as a substrate. By inserting a protective layer 120 for protecting the metal electrode part 130, Part was prevented from being etched by polyamic acid which is a precursor of colorless transparent polyimide. As shown in the cross-sectional structure of FIG. 1, transparent flexible polyimide 110 is present between intermediate intervals of the metal electrode portions 130, so that a completely integrated and integrated shape is shown. In order to improve the oxidation resistance and the conductive property of the metal electrode part 130 such as a copper mesh, the additional conductive layer 140 may be formed of a metal nano, micro-belt or metal mesh type transparent electrode 100 embedded in the polyimide, A metal nano, a micro-belt, or a metal mesh including a conductive protective film having a dense thin film structure can be embedded in a transparent polyimide substrate to produce a highly heat-resistant transparent electrode having a uniform surface. The conductive layer 140 may be formed by a DC or RF sputtering method, a pulsed laser deposition (PLD) method, a thermal evaporation method, or a sputtering method using an inorganic thin film layer having a thickness ranging from 10 nanometers (nm) to 200 nanometers The transparent electrode 100 may be coated on the transparent electrode 100 using any one of E-beam evaporation, Chemical Vapor Deposition, and Atomic Layer Deposition. The protective layer may be made of any one of SiO ₂ , SiN, MgO, ZnO, SnO ₂ , WO ₃ , Fe ₂ O ₃ , Fe ₃ O ₄ , NiO, TiO ₂ , ZrO ₂ , Al ₂ O ₃ , B ₂ O ₃ , _{Cr 3 O 4, Cr 2 O} 3, CeO 2, Nd 2 O 3, Sm 2 O 3, Eu 2 O 3, Gd 2 O 3, Tb 4 O 7, Dy 2 O 3, Er 2 O 3, Yb 2 O ₃ and Lu ₂ O ₃ . In another embodiment, the protective layer may comprise a polymer wherein the molecular weight of the polyallylamine hydrochloride having oxidation resistance ranges from 10,000 to 450,000.

FIG. 2 is a schematic plan view of a highly heat-resistant transparent electrode in which an electrode layer (metal nano, micro-belt or metal mesh) is embedded in a transparent polyimide substrate according to an embodiment of the present invention. As shown in the plane conceptual diagram, the shape of the electrode is not particularly limited if it is advantageous in terms of conduction from metal nano, micro-belt or metal mesh. The metal electrode layer 120 in the plan view is a metal having a thickness in the range of 100 nanometers (nm) to 20 micrometers (μm) in the electrode wiring thickness, and a gap of 10 millimeters (mm) ) Range so that the conductivity and the transmittance can be adjusted according to the wiring thickness and the wiring interval. The transparent polyimide 110 exists in a rectangular shape having a uniform height corresponding to the height of the electrode portion on the surface in such a form as to fill the space between the wiring electrodes and not to impede the conductive property such as covering the upper end of the electrode portion. This makes it possible to easily obtain a transparent transparent electrode having a uniform surface.

FIG. 3 is a diagram illustrating a manufacturing process of a highly heat-resistant transparent electrode in which a metal mesh patterned in the form of a metal nano, a micro-belt, or a grid rather than a grid pattern is embedded in a transparent polyimide substrate according to an embodiment.

Step S10 is a step of depositing a metal thin film layer on a glass substrate. Here, the deposition method may be a DC or RF sputtering method, a pulsed laser deposition (PLD) method, a thermal evaporation method, an E-beam evaporation method, a chemical vapor deposition method or an atomic layer deposition method Deposition) may be used.

Step S20 is a step of forming a polymer mask on the metal thin film layer. For example, a polymer mask can be formed on the metal thin film layer using an electrospinning process or an electrohydraulic patterning method.

Step S30 may be a step of improving the adhesion property between the polymer mask and the metal thin film layer and making a junction at the interface between the polymer mask fibers. For this purpose, the adhesion can be improved by using the swelling phenomenon of the polymer, UV-Ozone, or plasma treatment.

Step S40 may be a step of etching the metal thin film portion not covered by the polymer mask in the metal thin film layer. In other words, the step S40 may be a process of touching a portion of the metal thin film layer not protected by the polymer mask, and etching the metal thin film layer by a wet method to make an electrode of a desired shape.

Step S50 may be a step of coating a protective layer on the metal electrode (metal nano, micro-belt or metal mesh electrode) obtained through etching. For example, as a protective layer, a metal, a polymer, and an oxide layer or the like may be coated on the metal electrode to protect the metal electrode from etching by the polyamic acid solution.

Step S60 may be a step of coating the polyamic acid solution on the metal electrode covered with the protective layer. As a more specific example, step S60 may be a process of coating a polyamic acid solution on a metal mesh electrode in the form of a metal nano, micro-belt, or grid, which is not formed in a grid shape including a protective layer formed on a glass substrate.

Step S70 may be a step of imidizing heat treatment of the polyamic acid solution. For example, the polyamic acid solution may be converted to polyimide by heat treatment.

Step S80 may be a step of separating the flexible transparent electrode in which the metal electrode and the colorless transparent polyimide are integrated from the glass substrate. The metal electrode may be in the form of a metal nano that is not arranged in a grid shape, or a metal mesh that is arranged in a micro belt or grid shape.

Step S90 may be a step of coating a conductive film on the integrated flexible transparent electrode surface.

The present invention will be described in more detail with reference to the following specific examples. It is to be understood that the present invention is not limited thereto.

Example  1: metal sacrifice Thin film layer  deposition

An RF sputtering method equipped with a 3-inch copper target was used for copper metal sacrificial thin film deposition. Copper films were deposited for 20 minutes at 80W and argon at 0.01 torr while rotating the glass substrate. Based on such an embodiment, FIG. 4 shows a cross section of a copper metal sacrificial layer deposited on a glass substrate for 20 minutes, and the thickness of the copper sacrificial layer of the present invention is about 200 nanometers (nm) Respectively.

Example  2: Polymer mask formation

Polymer masks were formed in the form of a random arrangement instead of a grid shape by using an electrospinning device on the copper thin film. The grid-shaped mesh masks were formed using EHD equipment (ENJET, cNP-Expert-C) Respectively. In the present embodiment, PVAc (polyvinyl acetate) and PAN (polyacrylonitrile) polymers were prepared to form a polymer mask, but the present invention is not limited to specific polymers.

In the electrospinning process, 2.6 g, 3.15 g and 3.5 g of PVAc were added to 10 ml of DMF (N, N-dimethylformamide) solvent to prepare nano and micro-belt masks of various thicknesses and stirred at a rotational speed of 500 rpm at room temperature for 12 hours Solution. The solution thus prepared was placed in a syringe (ILS, 500 μl micro-syringes) and connected to a syringe pump. The spinning solution was pushed out at a discharge rate of 0.5 μl / min. ) And the current collector substrate was set to 15 kV. As the current collector to which the PVAc polymer was transferred, a glass substrate on which a Cu thin film of 200 nanometers (nm) thickness prepared in Example 1 was deposited was used, and the distance between the nozzle and the current collector was set to 500 μm.

Figures 5 and 6 are optical, scanning electron micrographs of a nano, micro-unit belt in the form of a random array of PVAc masks obtained after electrospinning. It can be seen that the one-dimensional polymer mask is transferred in the form of fiber, and the part that is not adhered to the surface at the contact point between the mask fibers is formed. The diameter of the polymer mask is 250 nm ~ 3 μm and it is freely adjustable according to the concentration of the electrospinning solution .

In the EHD jet printing process, 5 mg of CTAB (Cetylammonium bromide) was mixed with 300 mg of PAN (polyacrylonitrile) in 3.0 g of DMF (N, N-dimethylformamide) to control surface tension and smooth patterning. The mixture was stirred at 500 rpm for a period of time to prepare a solution. The solution was placed in a syringe (ILS, 500 μl micro-syringes) and connected to a syringe pump. The spinning solution was pushed at a discharge rate of 0.6 μl / min. μm of outer diameter) and the collector substrate was set to 1.4 kV. As the collector plate on which the PAN polymer was patterned, a glass substrate on which a Cu thin film of 200 nanometers (nm) thickness prepared in Example 1 was deposited was used, and the distance between the nozzle and the collector was set to 500 μm.

7 is an optical microscope photograph of the PAN mask obtained after EHD jet printing and patterned in the form of a mesh. Dimensional polymer meshes were formed. The diameter of the polymer meshes was about 5-7 micrometers (μm), and the spacing between the masks was about 400 micrometers (μm).

Example  3: Polymer Mask Annealing  fair

In order to improve the adhesion property between the polymer mask patterned in the desired shape and the glass substrate coated with the metal thin film on the metal sacrifice layer obtained in Example 2 and to make the junction point at the contact point between the mask fibers, Was exposed to DMF (N, N-dimethylformamide) steam at 60 < 0 > C for 30 seconds. In the case where a space is formed between the PVAc or PAN polymer used as the patterning mask and the glass substrate coated with the metal thin film, since the etching solution can not penetrate and an electrode having a uniform wiring diameter can not be manufactured, Is very important. In order to prevent the PVAc or PAN polymer from being washed out in the DMF solvent, a small amount of DMF solvent is added to the beaker, and the substrate is placed in direct contact with DMF to adjust the temperature to 60 ° C. The lid of the beaker is then closed. PAN polymer was attached to the metal substrate. A polymer mask coated on a copper foil in a desired shape can serve as a hard mask, and only a portion of the copper thin film that is not protected by a polymer mask can be etched by dry etching or wet etching.

8 and 9 show photographs of an optical microscope and a scanning electron microscope after a nano-micro-belt polymer mask having a random arrangement is exposed to an organic solvent and annealed. It can be seen that after the organic solvent annealing, not only the PVAc mask was sufficiently adhered to the metal thin film, but also the adhesion point was formed at the contact point between the mask fibers, so that the PVAc mask was uniformly adhered to all portions without being separated from the metal thin film. In addition, the swelling of the mask polymer through annealing resulted in an increase in the diameter of the mask fiber from 250 nm to 3 μm to 1 μm to 10 μm.

FIG. 10 shows an optical microscope photograph after polyacrylonitrile (PAN) polymer mesh mask is annealed by exposure to an organic solvent. After the organic solvent annealing, the adhesion to the substrate was increased, and the PAN fiber, which is a polymer mesh mask, also increased in diameter from 7 micrometers (μm) to 10 micrometers (μm).

Example  4: metal thin film Sacrificial layer Etching

In the fourth embodiment, wet etching was performed as a chemical method. In etching solution for copper thin film sacrificial layer etching, 0.486 g of FeCl ₃ was added to 1 L of deionized water and sufficiently dissolved at room temperature for 10 minutes. At this time, prepare a low-concentration solution containing 0.243 g of FeCl _{3 in} 1 L of deionized water for etching a fine pattern. Place the etching solution in a separating funnel and spread evenly over the metal sacrificial layer. The substrate was etched with a high concentration of etchant until it became transparent and then etched with a low concentration etchant for 1 minute. As a result, all of the metal thin film portions except for the metal thin film portions that were patterned and protected with the polymer were all etched. After the etching process, deionized water flowing through the electrodes was rinsed several times and washed for 1 minute at 60 ° C in dimethylformamide (DMF) to remove the PVAc or PAN mask present on the copper electrode.

Figs. 11 and 12 are optical microscope and scanning electron micrographs of a copper nano / micro-belt electrode having a random arrangement formed on a glass substrate. In FIG. 12, the diameters of the copper belt electrodes have values similar to those of the annealed polymer mask shown in FIGS. 8 and 9 at 800 nm (upper photo) and 3 μm (lower photo), respectively, and two scanning electron micrographs of FIG. It was confirmed that the diameter of the metal belt can be adjusted from nano unit to micro unit simply and easily by controlling the diameter of the polymer mask.

13 is an optical microscope photograph of a copper mesh electrode formed on a glass substrate. The copper mesh diameter has a value between 10 micrometers (μm) similar to the annealed polymer mask formed in FIG. 6, and the spacing between the electrodes is 400 micrometers (μm). Based on the above results, it was confirmed that the polymer mask is not damaged from the etchant, and thus the hard mask can sufficiently function. As a result, it is confirmed that the electrode is very similar to the mask shape after etching.

Example  5: Copper On the electrode layer Polyamic acid  Protective layer coating from solution

In order to prevent the copper electrode formed on the organic substrate from being etched away from the polyamic acid (polyimide precursor solution), a 2.5 wt% polyallylamine hydrochloride (PAH) solution dissolved in deionized water was prepared and subjected to a two- Lt; / RTI > The spin coating conditions were 800 rpm in the first step, 10 seconds in the acceleration speed, 5 seconds in the retention time, and set at 3000 rpm in the second step, 10 seconds in the acceleration time, and 30 seconds in the retention time.

FIG. 14 is a microscope showing the degree of etching of copper by a polyamic acid with or without a PAH protective layer on a thin copper thin film layer. When the PAH protective layer is coated at different rotational speeds, the PAH protection layer protects the copper from the etching by the polyamic acid, irrespective of the rotational speed, so that the copper color even after contact with the polyamic acid can be confirmed. On the other hand, in the case of the copper thin film specimen without the protective layer, the copper color became clear after the contact with the polyamic acid, and the thin film was etched. As a result, it can be seen that when polyamic acid is etched into the copper layer and the polyamic acid is coated without a protective layer such as PAH, the conductivity of the copper electrode may be seriously damaged.

Example  6: Copper The electrode layer  Integration of transparent polyimide

In order to integrate the metal electrode layer formed on the glass substrate with the transparent polyimide substrate, a polyamic acid solution which is a precursor of a colorless transparent polyimide should first be prepared, and the polyamic acid is made by polymerization reaction of an anhydride and an amine. In the present invention, 8 g of DMF was used as an organic solvent, 4.073 g of 6FDA (4,4 '- (hexafluoroisopropylidene) diphthalic anhydride) having a trifluoromethyl group as the anhydride and a sulfone structure And 2.276 g of ammonium persulfate (APS) was added thereto, followed by stirring at about 20 ° C and 500 rpm for 5 hours to synthesize a liquid polyamic acid. The synthesized polyamic acid solution was applied uniformly to the top of a randomly arranged copper nano, micro-belt or grid-shaped copper mesh electrode obtained from Example 5 at a thickness of 100 micrometers (μm) using a doctor's blade . The coated polyamic acid was heated to 2 ° C / min and heat-treated at 100 ° C, 200 ° C and 230 ° C for 1 hour to form a colorless transparent polyimide, and then immersed in deionized water for 30 minutes or more at room temperature to remove the polyimide film from the glass substrate A flexible transparent electrode in which the copper electrode is embedded in the transparent polyimide film can be obtained.

FIG. 15 is a photograph of a surface of a transparent electrode having a random arrangement of copper nano-particles and a micro-belt electrode embedded in a colorless transparent polyimide substrate.

Fig. 16 shows a surface and cross-sectional photograph of a scanning electron microscope photograph of a transparent electrode in which a grid-shaped copper mesh electrode is embedded in a colorless transparent polyimide substrate. 15 and 16, it is confirmed that there is almost no step between the electrode and the transparent polyimide, and the electrode portion is exposed to the surface without the portion blocked by the polyimide, so that there is no problem in electrical contact on the surface .

FIG. 17 is a scanning electron microscope sectional photograph before and after a metal micro-belt electrode having a random arrangement is embedded in a transparent polyimide substrate, FIG. 18 is a cross-sectional photograph of a metal mesh electrode having a grid shape before and after being embedded in a transparent polyimide substrate, Sectional view of the electron microscope.

17 and 18 are photographs before being embedded in the polyimide substrate, and the photographs after the lower photograph of FIG. 17 and the lower photograph of FIG. 18 are embedded in the polyimide substrate. Before the electrode layer was embedded in the transparent polyimide substrate, there was a step as much as the thickness of the metal thin film deposited in Example 1, but after the metal electrode layer was completely embedded in the polyimide, the surface had a very uniform surface . The degree of smoothness of the surface improves the interfacial property when the transparent electrode is used to make the device, and thus it shows applicability to many devices.

FIG. 19 is an optical microscope photograph of the mesh diameter of a transparent electrode in which a copper mesh is embedded in a transparent polyimide substrate. FIG. The electrode thickness in Figure 19 (a) of Figure 19 is about 3 micrometers (m), but in Figure 19 (b) of Figure 19 it is about 5 micrometers (m). When the electrode thickness is thinned, the conductivity characteristics are improved, but when the transmission characteristics are deteriorated and thinned, the opposite characteristics are exhibited.

20 shows an optical microscope photograph according to the interval between the mesh wirings of the transparent electrode embedded in the transparent polyimide substrate of the copper mesh. The electrode interval in the photograph a) of FIG. 20 is about 100 micrometers (μm), the electrode interval in the photograph b) of FIG. 20 is about 200 micrometers (μm) Is about 400 micrometers (μm), respectively. As the electrode interval is widened, the conductive characteristics are deteriorated and the transmission characteristics are improved. When the electrode interval is reduced, the conductive characteristics are improved and the transmission characteristics are degraded.

Example  7: Metal on transparent polyimide The electrode layer Intrinsic  Above the transparent electrode Conductive layer  coating

On the surface of the electrode portion of the transparent polyimide film having the metal electrode layer thereon, a sputtering method with a 2-inch ZnO target was used for deposition of a conductive layer for enhancing the oxidation resistance of the electrode. ZnO thin films were deposited for 10 minutes at 40W and argon at 0.01 torr while rotating the glass substrate. Based on such an embodiment, a copper mesh was finally embedded in a transparent polyimide substrate to produce an integrated high heat-resistant transparent electrode.

21 is a scanning electron microscope (SEM) image of a section of a highly heat-resistant transparent electrode in which a copper electrode layer is embedded in a transparent polyimide substrate based on Example 7. It can be seen that the ZnO thin film layer completely covers the electrode surface to a thickness of about 200 nanometers (nm). Such a conductive layer not only provides stability in terms of conductivity, but also can be advantageously used in terms of heat resistance, corrosion resistance, and oxidation resistance.

Comparative Example  1: Copper Mesh Unintegrated  Transparent polyimide transparent electrode

To obtain a transparent polyimide film, 4.073 g of 6FDA (4,4 '- (hexafluoroisopropylidene) diphthalic anhydride) having an trifluoromethyl group as an anhydride in 8 g of DMF as an organic solvent and 4.07 g of APS 2.276 g of ammonium persulfate was added and stirred at about 20 ° C and 500 rpm for 5 hours to form a liquid polyamic acid. Use a doctor's blade to uniformly apply a liquid polyamic acid to the surface of the glass substrate at a thickness of 100 μm. The coated polyamic acid was heated to 2 ° C / min and heat treated at 100 ° C, 200 ° C and 230 ° C for 1 hour, and immersed in deionized water at room temperature for 30 minutes or longer to obtain a transparent polyimide film. A copper mesh transparent electrode not contained in the polyimide can be obtained from the transparent polyimide film through the steps 1, 2, and 3 of the transparent polyimide film sequentially.

22 is a scanning electron microscope (SEM) image of a copper mesh non-integral transparent polyimide transparent electrode prepared on the basis of Comparative Example 1. FIG. The shape of the copper mesh is maintained, and the interval between the electrodes is 200 μm and the width is 3 μm. As can be seen from the enlarged photograph on the right side of FIG. 14, unlike the highly heat-resistant transparent electrode built in the transparent polyimide substrate made from the embodiment, the copper mesh non-integral transparent polyimide transparent electrode has a transparent polyimide substrate and a copper mesh electrode And the height difference between them is about 200 nanometers (nm). In the case of such an electrode, since the copper mesh is not embedded in the substrate, the copper mesh can be easily separated from the substrate, and electrical shorting can occur due to the step difference.

FIG. 23 is a table showing sheet resistance and transmittance of a high heat-resistant transparent electrode in which a copper nano-scale, micro-belt having a random arrangement manufactured on the basis of the embodiment is embedded in a transparent polyimide substrate. The sheet resistances were 2.13 and 3.29 ohm / sq for the electrode diameter of 1 ~ 10 μm, respectively, and the permeability was 75.1% and 83.6%, respectively.

24 is a table showing sheet resistance and transmittance of a high heat-resistant transparent electrode in which a copper mesh fabricated on the basis of the embodiment is embedded in a transparent polyimide substrate. The sheet resistances at 25, 205, and 280 ohm / sq were 100, 200, and 400 micrometers, respectively, and the transmittances were 75.64, 86.53, and 85.96%, respectively. As the electrode spacing increased, the permeability increased and the sheet resistance decreased.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments described in the present invention are not intended to limit the technical spirit of the present invention but to illustrate the present invention. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents thereof should be construed as being included in the scope of the present invention.

Claims (28)

A metal electrode layer having a metal line shape or a grid shape randomly arranged or aligned in a specific direction; And
The transparent electrode layer
/ RTI >
Wherein the metal electrode layer is integrated on one surface of the transparent substrate and has a flat surface,
When the metal constituting the metal electrode layer is copper, in order to prevent copper etching by the polyamic acid solution, which is a transparent polyimide precursor solution used for manufacturing the transparent substrate, the metal electrode layer and the transparent substrate are in contact with each other The protective layer
Further comprising a transparent electrode layer formed on the transparent electrode. delete The method according to claim 1,
Wherein the protective layer comprises one or more selected from metals, polymers, and ceramics having a thickness ranging from 10 nanometers (nm) to 100 nanometers (nm). The method according to claim 1,
Wherein the protective layer comprises one or two or more metals selected from gold, silver, nickel, platinum and titanium having oxidation resistance. The method according to claim 1,
The protective layer may include at least one of SiO ₂ , SiN, MgO, ZnO, SnO ₂ , WO ₃ , Fe ₂ O ₃ , Fe ₃ O ₄ , NiO, TiO ₂ , ZrO ₂ , Al ₂ O ₃ , B ₂ O _{3 , Cr 3 O 4, Cr 2} O 3, CeO 2, Nd 2 O 3, Sm 2 O 3, Eu 2 O 3, Gd 2 O 3, Tb 4 O 7, Dy 2 O 3, Er 2 O 3, Yb ₂ O _3, and Lu ₂ O ₃ . The method according to claim 1,
Wherein the protective layer comprises a polymer having a molecular weight ranging from 10,000 to 450,000, the polyallylamine hydrochloride having oxidation resistance. The method according to claim 1,
In order to adjust the conductivity and the transmittance according to the wire thickness and the wire spacing, the distance between the electrode wires is preferably in the range of 5 micrometers (μm) to 10 millimeters (mm). Wherein the transparent electrode is formed in a controlled manner. The method according to claim 1,
Wherein the transparent substrate comprises a colorless polyimide transparent substrate. The method according to claim 1,
Wherein the transparent substrate has a transmittance of 80 to 95% at a wavelength of 550 nanometers (nm) in a visible light region through an imidization heat treatment from a polyamic acid solution which is a polyimide precursor. The method according to claim 1,
Wherein the substrate thickness of the transparent substrate is in the range of 5 micrometers (μm) to 100 micrometers (μm). 10. A transparent electrode comprising a high heat-resistant flexible transparent electrode according to any one of claims 1 to 10,
The transmittance is in the range of 80 to 90%
Wherein the resistance is in the range of 0.1 to 200 W / sq. A method of manufacturing a transparent electrode having high heat resistance,
(a) depositing a metal thin film layer on a substrate;
(b) forming a polymer nanofiber electrode mask on the metal thin film layer;
(c) etching the unprotected metal thin film portion with the polymer nanofiber electrode mask;
(d) coating a precursor solution on the metal electrode layer obtained through the etching; And
(e) heat-treating the precursor solution to produce a highly heat-resistant flexible transparent electrode having the metal electrode layer embedded in one surface of the film and having a flat surface
The method of claim 1, 13. The method of claim 12,
The step (a)
A metal thin film layer having a thickness ranging from 10 nanometers (nm) to 1 micrometer (μm) may be formed on the upper surface of the substrate by DC or RF sputtering, pulsed laser deposition (PLD), thermal evaporation, Characterized in that the sheet resistance is deposited in the range of 0.001 to 10 Ω / sq using any one of E-beam evaporation, chemical vapor deposition, and atomic layer deposition. (JP) METHOD FOR MANUFACTURING RESISTANT TRANSPARENT ELECTRODE. 13. The method of claim 12,
The step (a)
Wherein an adhesion layer formed of at least one of titanium, chromium, platinum, and nickel is formed between the substrate and the metal thin film layer to increase adhesion characteristics between the substrate and the metal thin film layer before the metal thin film layer is deposited. Wherein the transparent electrode is deposited between the metal thin film layers. The method of claim 12, wherein
The step (a)
Wherein at least one of an oxygen plasma treatment and an ozone ultraviolet treatment is performed to increase adhesion characteristics between the substrate and the metal thin film layer before the metal thin film layer is deposited. 13. The method of claim 12,
The polymer nanofiber electrode mask may be formed on the metal thin film layer in the form of one of a belt mask having a random arrangement, a belt mask having an arrangement arranged in one direction, and a belt mask having an arrangement arranged in a grid shape by electrospinning Wherein the transparent electrode is directly drawn. 13. The method of claim 12,
Wherein the polymer nanofiber electrode mask is drawn in a grid shape directly on the metal thin film layer using an electrohydrodynamic jet deposition process. 13. The method of claim 12,
Wherein the polymer nanofiber electrode mask comprises a polymeric fiber mask formed through any one of roll-to-roll processing, gravure printing, and photolithography. A method of manufacturing a flexible transparent electrode. 13. The method of claim 12,
The thickness of the wiring of the polymer nanofiber electrode mask is in the range of 500 nanometers (nm) to 10 micrometers (μm)
Wherein the interval between the wirings of the polymer nanofiber electrode mask is in the range of 5 micrometers (μm) to 10 millimeters (mm). 13. The method of claim 12,
The polymer nanofiber electrode mask is not soluble in water. The polyacrylonitrile (PAN), polyvinylacetate (PVAc), polymethylmethacrylate (PMMA), polystyrene (PS) Wherein the transparent electrode is formed using at least one polymer selected from the group consisting of polyvinyl chloride (PVC), polycarbonate (PC), and polycarbonate (PC). 13. The method of claim 12,
Prior to step (c)
In order to improve adhesion between the metal thin film layer and the polymer nanofiber electrode mask, the polymer nanofiber electrode mask is immersed in a solvent capable of swelling, such as acetone, ethanol, N, N-dimethylformamide (DMF , Dimethyformamide), N-methyl-2-pyrrolidone (NMP), dimethylaceteamide (DMAc) and tetrahydrofuran (THF) Characterized in that solvent annealing is carried out at a temperature capable of evaporation within 30 seconds to 5 minutes. 13. The method of claim 12,
The step (c)
When the gap between the wirings of the polymer nanofiber electrode mask and the wiring thickness are in the range of 100 nanometers (nm) to 1 micrometer (μm), the ion beam etching, the subtractive plasma etching and the high temperature chlorine gas etching The metal thin film is etched using at least one dry method,
Distilled water - ferric chloride (FeCl ₃ ), distilled water - hydrochloric acid (HCl) - ferric chloride (FeCl ₃ ), distilled water - nitric acid (HNO ₃ ), distilled water - nitric acid (HNO ₃₎ - silver nitrate (AgNO- _3), distilled water - ammonium persulfate _{((NH 4) S 2 O} 8) , and distilled water - ammonium chloride (NH ₄ CI), - at least one solution of the aqueous ammonia Wherein the metal thin film is etched by using a wet process using the metal thin film. 13. The method of claim 12,
After the step (c)
(f) coating a protective layer for the precursor solution on the metal nano- and micro-belt-shaped or metal mesh-shaped metal electrode layer obtained through the etching
Further comprising the step of forming a transparent electrode on the transparent electrode. 24. The method of claim 23,
The step (f)
When the protective layer is made of a metal or a ceramic, it is possible to use a DC or RF sputtering method, a pulsed laser deposition (PLD) method, a thermal evaporation method, an E-beam evaporation method, a chemical vapor deposition method, The protective layer may be coated in a dense thin film form using any one of atomic layer deposition,
When the protective layer is a polymer, a polyallylamine hydrochloride (PAH) solution having a concentration range of 1 to 10 wt% at room temperature may be applied by any one of a spin coating method, a printing method, a dipping coating method and a spraying method Wherein the protective layer is coated on the transparent electrode by using a photoresist. 13. The method of claim 12,
The step (d)
The polyamic acid film formed by coating the polyamic acid solution as the precursor solution on the substrate having the metal electrode layer is heat treated in a gas containing hydrogen at a temperature ranging from 150 to 250 ° C to produce a colorless transparent and flexible polyimide substrate Wherein the transparent electrode is a transparent electrode. 13. The method of claim 12,
(g) separating the high heat-resistant flexible transparent electrode, which is integrated with the metal electrode layer on one surface of the film, from the substrate; And
(h) coating an additional conductive film on the surface of the high heat-resistant flexible transparent electrode separated from the substrate
Further comprising a step of forming a transparent electrode on the transparent electrode. 27. The method of claim 26,
The step (g)
Wherein the high heat resistant flexible transparent electrode is separated from the substrate by immersing the film in which the metal electrode layer is embedded in distilled water for 1 to 30 minutes. 27. The method of claim 26,
The step (h)
An inorganic thin film layer having a thickness in the range of 10 nanometers (nm) to 200 nanometers (nm) is formed on the top of the metal electrode layer in order to increase resistance to oxidation and resistance to external physical and chemical stimuli As the additional conductive film, an RF sputtering method, a pulsed laser deposition (PLD) method, a thermal evaporation method, an E-beam evaporation method, a chemical vapor deposition method and an atomic layer deposition method Wherein the deposition is performed using any one of a deposition method, a deposition method, and a deposition method.

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