KR101932584B1 - Structure-Integrated Flexible Transparent Electrode and Method for Manufacturing the Same - Google Patents

Abstract

The present invention relates to a flexible transparent electrode in which a concavo-convex structure for improving optical characteristics is integrated on a surface of a flexible transparent electrode in which metal nanowires are embedded. The present invention also relates to a flexible transparent electrode in which a concave-convex structure for non-optically patterning a flexible transparent electrode in which metal nanowires are embedded and for improving optical characteristics is integrated on the surface.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a flexible transparent electrode,

The present invention relates to a flexible transparent electrode in which a concavo-convex structure for improving optical characteristics is integrated on a surface of a flexible transparent electrode in which metal nanowires are embedded. The present invention also relates to a flexible transparent electrode in which a concave-convex structure for non-optically patterning a flexible transparent electrode in which metal nanowires are embedded and for improving optical characteristics is integrated on the surface.

Generally, a transparent transparent electrode can be prepared by coating a metal nanowire on a flexible substrate or by coating a metal nanowire on a substrate having a sacrificial layer and separating it with a polymer. The metal nano wire embedded flexible electrode, which is formed by coating the metal nanowire on the sacrificial layer and removing it, has a low possibility of occurrence of short circuit when the electronic device is applied due to low surface roughness,

In order to apply a flexible transparent electrode based on a metal nanowire to an electronic device, a patterning process is indispensable and is mainly performed by using a photolithography method. That is, a photoresist is coated on a flexible transparent electrode based on a metal nanowire, and light is irradiated using an exposure apparatus, and then a pattern can be formed through development and etching processes. However, in the case of the photolithography process, additional materials such as photoresist are required, and the process equipment is expensive, raising a problem of raising the process cost.

In order to solve the problem of process unit cost of photolithography, several studies have been made to pattern metal nanowire-based flexible transparent electrodes by methods other than photolithography. In other words, a method of forming a pattern by selectively etching metal nanowires using laser equipment has been proposed. A method of selectively transferring metal nanowires on a flexible substrate using microcontact printing, a method of forming a metal nanowire seed on a substrate And a method of fabricating a flexible transparent electrode based on a metal nanowire in which a pattern is formed by selectively forming the metal nanowire. In addition, a method of patterning metal nanowires on a substrate using inkjet printing or gravure offset printing equipment has been proposed. When a curable polymer is coated thereon and cured, a flexible transparent electrode having embedded patterns of metal nanowires can be manufactured have.

However, all of the above methods require expensive patterning equipment and complicated processes. Therefore, the problems of photolithography can not be totally removed, and a new patterning technology capable of securing cost competitiveness, especially a metal nanowire embedded type Development of new patterning technology suitable for flexible transparent electrodes is needed.

That is, since the flexible transparent electrode having the embedded metal nano wire has a smooth surface, it exhibits superior performance to the transparent electrode coated with the metal nanowire on the flexible substrate when the electronic device is applied. However, there is little research to improve the fabrication process of metal nanowire embedding type transparent electrode, and it is a simple modification step of metal nanowire electrode patterning technique coated on flexible substrate. In other words, as shown in the following patents, metal nanowires are patterned using expensive equipment, and polymer nanotubes are coated and cured on the metal nanowires to fabricate patterned metal nanowires embedded flexible electrodes. The details and limitations are as follows Respectively.

Korean Patent No. 10-1161301 discloses a method for manufacturing a semiconductor device, comprising: (a) a step of pretreating a substrate by irradiating plasma on a substrate surface (step 1); Forming a metal wiring on the substrate pretreated in step 1 (step 2); Coating the curable polymer on the substrate having the metal wiring formed thereon in step 2 and curing the metal to form a polymer layer having the metal wiring embedded therein (step 3); And separating the polymer layer prepared in the step 3 from the substrate of the step 1 (step 4). The method of manufacturing a flexible substrate in which a metal wiring is embedded using plasma is disclosed. The metal wiring of step 2 is formed by inkjet printing, gravure printing, gravure offset, aerosol printing, screen printing, electroplating, vacuum deposition or photolithography. The above-mentioned patent discloses a method of delamination of a polymer material from a substrate by a plasma treatment. However, as described above, expensive equipment is required to form a metal wiring, and there is a problem in that the process is complicated.

In addition, Korean Patent No. 10-1191865 discloses a method comprising: (1) coating a sacrificial layer made of water, an organic solvent-soluble polymer, or a photodegradable polymer on a substrate; Forming a metal wiring on the sacrificial layer of step 1 (step 2); Coating a curable polymer on the sacrificial layer formed with the metal interconnection of step 2 and curing it to prepare a polymer layer having a metal interconnection embedded therein (step 3); And separating the substrate of step 1 and the polymer layer of step 3 by dissolving or removing only the sacrifice layer present between the substrate of step 1 and the polymer layer of step 3 in water or an organic solvent, 4) is embedded in a metal substrate.

Also, there is provided a method of manufacturing a semiconductor device, comprising the steps of: (1) coating a release layer on a substrate; Coating a sacrificial layer made of water or organic solvent-soluble polymer or photodegradable polymer on the peeling layer coated in step 1 (step 2); Forming a metal wiring on the sacrificial layer of step 2 (step 2); Coating the curable polymer on the sacrificial layer formed with the metal interconnection of step 3 and curing the metal to form a polymer layer having the metal interconnection embedded therein (step 4); Removing the substrate and the release layer of step 1 by applying a physical force (step 5); And a step (step 6) of dissolving or removing only the sacrifice layer exposed by removing the substrate of step 1 in water or an organic solvent (step 6) in step 5 (step 6). .

The patent provides a method for cleanly peeling a flexible substrate from a substrate by removing a sacrificial layer applied to the substrate using light or a solvent. However, in order to form a metal wiring, expensive equipment such as inkjet printing, gravure printing, gravure offset, aerosol printing, screen printing, electroplating, vacuum deposition or photolithography is required as in the above-mentioned Japanese Patent No. 10-1191865 , The process is complicated. In addition, since the sacrificial layer is coated on the substrate and is fixed, it is difficult to completely remove the sacrificial layer. In order to solve this problem, by exposing the sacrificial layer by peeling the sacrificial layer by coating the release layer, the area exposed to the organic solvent or light can be increased, but an additional step of forming the release layer is required, If the sacrificial layer is not completely removed, there is a problem that may affect the physical properties of the flexible substrate.

Next, the patterned flexible transparent electrode is attached to the transparent electrode to improve the characteristics of the optoelectronic device in order to improve its characteristics in the application of the optoelectronic device. . For example, in an organic solar cell, external light enters a light absorbing layer through a transparent electrode and converts light into electricity in the light absorbing layer. Therefore, the amount of light incident on the light absorbing layer is very important, and a lens having a light collecting function is manufactured and adhered to the outside of the transparent electrode to increase the amount of incident light and the light conversion efficiency (light-electricity conversion efficiency). However, since the transparent electrode manufacturing process, the optoelectronic device manufacturing process, the light collecting film manufacturing process, and the attaching process are separately performed, the process efficiency is decreased and the process cost is increased. In addition, there is a problem that it is difficult to control the optical property by the difference in refractive index between the medium of the material used for the transparent substrate and the medium of the material used for the structure. Accordingly, there is a need for a novel flexible transparent electrode manufacturing method that can increase the process efficiency by integrating the transparent electrode manufacturing process, the electrode patterning process, and the light collecting structure manufacturing process. However, to date, the research has been limited to the fabrication of transparent electrodes and optical films as independent processes and to attach them to transparent electrodes by separate processes.

Korean Registered Patent No. 10-1161301 (June 25, 2012) Korean Patent No. 10-1191865 (October 10, 2012)

SUMMARY OF THE INVENTION The present invention provides a method for manufacturing a flexible transparent electrode with a built-in structure capable of integrating a physical structure for changing a light path on a surface simultaneously with the production of a flexible metal nanowire-type transparent electrode. Specifically, the present invention provides a flexible transparent electrode having a structure that can increase the process efficiency by omitting the step of attaching or laminating a separate structure in manufacturing a solar cell or an OLED, and a method of manufacturing the same.

Another object of the present invention is to provide a flexible transparent electrode having a structure capable of solving the problem caused by the difference in refractive index due to the difference in the medium between the transparent electrode and the structure which may occur when a separate structure film is attached, and a method for manufacturing the same.

The present invention also relates to a flexible transparent electrode having a structure in which metal nanowires are embedded in an organic material, and a method for manufacturing the flexible transparent electrode, wherein the metal nanowires are embedded in an organic material To provide a flexible transparent electrode in which the structure for changing the optical path on the surface of the transparent electrode is unified without detaching the metal nanowires from the organic material substrate and a method for manufacturing the same.

The present invention also provides a flexible transparent electrode in which a structure capable of patterning is integrated in a relatively simple manner without requiring a photolithography process, a sacrificial layer removal process, and a wire coating process using expensive equipment, and a method for manufacturing the same do. Specifically, the present invention provides a novel patterning method for forming a pattern by controlling the adhesive force between a metal nanowire and a polymer resin by plasma or ultraviolet-ozone treatment of the polymer resin.

The present invention also provides a transparent electrode having a metal nanowire embedded in a curable polymer resin to solve the surface roughness caused by the use of the metal nanowire, And a method of manufacturing a flexible transparent electrode.

The inventors of the present invention have conducted studies to solve the problem of separately attaching a light control film when a metal nanowire impregnated transparent electrode is applied to an optoelectronic device. As a result, it has been found that a curable polymer resin It has been found that a metal nano wire impregnated transparent electrode having a physical structure for light control can be manufactured by forming a release layer made of an inert resin and forming an uneven structure in the release layer, Respectively.

In addition, the hydrophilic treatment of the release layer can improve the adhesion between the substrate and the metal nanowire. Particularly, when the hydrophilic treatment is partially performed using a mask, a fine pattern can be formed on the metal nanowire layer of the transparent electrode. And completed the present invention.

Specifically, the metal nanowire impregnated transparent electrode can be manufactured by coating a metal nanowire on a substrate having a release layer formed thereon, coating a curable polymer resin thereon, curing the metal nanowire, and separating the metal nanowire into a release layer. The inventors of the present invention formed a physical structure for light control on a substrate through various surface treatment processes or imprint processes such as a heat treatment process, a plasma treatment process, and an electrospinning process, and formed a release layer on the physical structure. Next, the metal nanowires were coated on the release layer having the same physical shape as the substrate, and UV curable polymer was coated and cured. Then, the flexible transparent electrode was fabricated by removing it from the release layer substrate and integrating the physical structure capable of optical path control.

One aspect of the present invention is

a) curing a substrate with a curable polymer resin and curing the substrate, forming a concave-convex structure on the surface through a surface treatment process or an imprinting process, applying a hydrophobic polymer resin on the concave- Forming a layer;

b) applying a metal nanowire solution to the entire surface of the release layer and then drying to form a metal nanowire coating layer;

c) coating the entire surface of the metal nanowire coating layer with a curable polymer resin and curing the metal nanowire coating to produce a polymer film having the metal nanowires embedded therein; And

d) separating the polymer film embedded with the metal nanowires from the release layer to produce a flexible transparent electrode having a metal nanowire layer having a concave-convex structure;

Wherein the hydrophobic polymer resin and the curable polymer resin are non-compatible with each other.

Another aspect of the present invention is a method for producing a molded article, comprising the steps of: a) applying a hydrophobic polymer resin to a substrate, drying the same with a mold made of a siloxane polymer having an uneven structure before the hydrophobic polymer resin is dried, Forming a release layer on which the concavo-convex structure is formed;

b) applying a metal nanowire solution to the entire surface of the release layer and then drying to form a metal nanowire coating layer;

c) applying a curable polymer resin on the metal nanowire coating layer and curing the polymer nanofibers to produce a polymer film having embedded metal nanowires; And

d) separating the polymer film embedded with the metal nanowires from the release layer or the hydrophobic polymer substrate to produce a flexible transparent electrode having a concavo-convex structure;

Wherein the hydrophobic polymer resin and the curable polymer resin are non-compatible with each other.

According to still another aspect of the present invention, in the step a), after forming a release layer having a concavo-convex structure on the substrate, a mask is placed on the release layer, and a hydrophilic treatment is performed on the release layer, step; And removing the mask to form a patterned metal nanowire layer.

In another aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of: providing a polymer film and a metal nanowire layer, the metal nanowire layer being patterned according to the shape of a mask; And the uneven structure is integrated with the surface of the metal nanowire layer to form a structure-integrated flexible transparent electrode.

Since the transparent electrode manufactured according to the manufacturing method of the present invention is formed by embedding the metal nanowire layer in the polymer film and simultaneously the uneven structure is integrated in the metal nanowire layer, , OLED and other electronic devices to change the optical path.

Therefore, it is possible to prevent deterioration of the optical characteristics due to the difference in refractive index according to the separate structure stacking, and it is possible to form the concavo-convex structure by a relatively simple method.

In addition, the present invention can provide a new patterning method capable of controlling the adhesive force between materials through plasma or ultraviolet-ozone treatment, thereby forming a pattern.

In addition, the present invention can produce a flexible transparent electrode having a pattern formed by a simple process as compared with a conventional method using photolithography.

In addition, the present invention is advantageous in that it does not require expensive equipment, is simple in process, and easily adjusts the line width of the pattern, compared with a method of forming patterns by gravure offset, gravure printing, inkjet prining and the like.

In the manufacturing method of the present invention, since the adhesion is controlled through the surface treatment and the pattern is formed due to the difference in adhesive force, the silver nanowire-based integrated structure type flexible transparent electrode having no trace of the silver nanowire being etched can be manufactured.

The flexible transparent electrode manufactured by the manufacturing method of the present invention is less likely to cause a short circuit when applied to an electronic material because the metal nanowire is embedded in the polymer resin and the surface is smooth, and can be applied to an OLED, a solar cell, and the like.

1 is an image of a transparent electrode obtained by photographing an uneven structure of a transparent electrode according to Example 1 of the present invention with an optical microscope (OM).
2 is an image obtained by photographing a pattern of a transparent electrode according to Example 2 of the present invention with an optical microscope (OM).
3 is a photograph showing a metal mask used in Example 4 of the present invention.
FIG. 4 is a graph illustrating the effect of dispersed light according to the structure of the structure-integrated flexible transparent electrode according to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described more fully hereinafter with reference to the accompanying drawings, It should be understood, however, that the invention is not limited thereto and that various changes and modifications may be made without departing from the spirit and scope of the invention.

Unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention is merely intended to effectively describe a specific embodiment and is not intended to limit the invention.

Also, the singular forms as used in the specification and the appended claims are intended to include the plural forms as well, unless the context clearly indicates otherwise.

In the present invention, the term " concavo-convex structure " means that the concave and convex portions are formed periodically, regularly, or randomly, and the form thereof is not limited. As a specific example, various structures such as a three-dimensional wrinkle structure and a micro lens structure can be introduced as a physical structure.

In the present invention, the "width of the recess" means the shortest length among the structures forming the concave portion in the concave-convex structure and the "width of the convex portion" means the shortest length among the structures forming the convex portion in the concave-convex structure .

'Incompatibility' in the present invention means that they have no compatibility with each other and have different solubility parameters and different release properties. Specifically, it means that the difference in solubility constant between the two resins satisfies the following expression (2).

[Formula 2]

2 < / =

In the above formula 2, the unit is J ^1/2 / cm ^2/3 .

In the present invention, 'release properties' are loosely attached to each other, meaning that they can be easily removed by applying a physical force using a finger or a cotton swab.

Hereinafter, one aspect of the present invention will be described in more detail.

The present invention relates to a method of manufacturing a transparent electrode by integrating a concave-convex structure in a transparent electrode by using a mold releasing property between a metal nanowire and a polymer resin and a moldability of a polymer resin. The present invention also relates to a simple and novel method of forming a pattern of transparent electrodes by controlling the adhesion between metal nanowires and polymeric resins.

The adhesion may be controlled using a hydrophilic treatment, more specifically a plasma or ultraviolet-ozone treatment. The metal nanowire can be fixed by treating the surface of the release layer made of the hydrophobic polymer resin having weak adhesion with the metal nanowire, that is, the release property, by plasma or ultraviolet-ozone treatment to oxidize the surface to have hydrophilicity . At this time, a pattern can be formed by partial hydrophilization by plasma or ultraviolet-ozone treatment using a mask. When the metal nanowires are applied after the plasma or ultraviolet-ozone treatment and the curable polymer resin is applied, the metal nanowires not subjected to plasma or ultraviolet-ozone treatment have weak adhesive force with the substrate due to the release layer, And the polymer film having the metal nanowires embedded therein is separated to form a pattern, and a flexible transparent electrode having a smooth surface can be produced.

More specifically, the first aspect of the method for manufacturing the structure-integrated flexible transparent electrode of the present invention

a) curing a substrate with a curable polymer resin and curing the substrate, forming a concave-convex structure on the surface through a surface treatment process or an imprinting process, applying a hydrophobic polymer resin on the concave- Forming a layer;

b) applying a metal nanowire solution to the entire surface of the release layer and then drying to form a metal nanowire coating layer;

c) coating the entire surface of the metal nanowire coating layer with a curable polymer resin and curing the metal nanowire coating to produce a polymer film having the metal nanowires embedded therein; And

d) separating the polymer film embedded with the metal nanowires from the release layer to produce a flexible transparent electrode having a metal nanowire layer having a concave-convex structure;

Wherein the hydrophobic polymer resin and the curable polymer resin are non-compatible with each other.

A second aspect of the method for manufacturing the integral transparent flexible electrode of the present invention

a) a step of applying a hydrophobic polymer resin to the substrate and drying the same before the hydrophobic polymer resin is dried in a state in which a mold made of a siloxane polymer having a concavo-convex structure is closely adhered to the substrate, Forming a release layer;

b) applying a metal nanowire solution to the entire surface of the release layer and then drying to form a metal nanowire coating layer;

c) applying a curable polymer resin on the metal nanowire coating layer and curing the polymer nanofibers to produce a polymer film having embedded metal nanowires; And

d) separating the polymer film embedded with the metal nanowires from the release layer or the hydrophobic polymer substrate to produce a flexible transparent electrode having a concavo-convex structure;

Wherein the hydrophobic polymer resin and the curable polymer resin are non-compatible with each other.

A third aspect of the method of manufacturing a structure-integrated flexible transparent electrode of the present invention

In the first aspect, a step of forming a release layer having a concavo-convex structure on the substrate in the step a), a step of positioning a mask on the release layer and performing a hydrophilization treatment to hydrophilize the maskless portion; And removing the mask, wherein the pattern is formed on the flexible transparent electrode.

A fourth aspect of the method for manufacturing a structure-integrated flexible transparent electrode of the present invention

Forming a release layer having a concavo-convex structure on the substrate in the step (a) of the second aspect, placing the mask on the release layer, and performing hydrophilization treatment to hydrophilize the maskless part; And removing the mask, wherein the pattern is formed on the flexible transparent electrode.

A fifth aspect of the method of manufacturing a structure-integrated flexible transparent electrode of the present invention

In the second or fourth aspect, the substrate may be cured by coating a curable polymer resin on the substrate before step a), and then the substrate may be subjected to a surface treatment or an imprinting process to form a concavo-convex structure on the surface, Coating a siloxane-based polymer on the above-mentioned siloxane-based polymer, and heat-treating the resultant to prepare a mold.

The first, second, third, fourth, and fifth aspects are only examples for explaining the present invention, but the present invention is not limited thereto.

In one embodiment of the present invention, the solubility parameter δ ₁ of the hydrophobic polymer resin and the solubility constant δ ₂ of the curable polymer resin The difference value Δδ in the following formula 1 may satisfy the following formula 2.

[Formula 1]

Δδ = | δ ₂ - δ ₁ |

[Formula 2]

2 < / =

In the above formula (2) units are J ^{1/2 /} cm ^2/3.

In one embodiment of the present invention, the contact angle of the surface of the release layer with respect to water before the hydrophilization treatment is 65 ° or more and the contact angle of the surface of the release layer after the hydrophilization treatment with water is 50 ° or less.

In one embodiment of the present invention, the hydrophilization treatment may be plasma, ultraviolet-ozone, electron beam or ion beam treatment.

In one embodiment of the present invention, the plasma or ion beam treatment may be performed using one or more gases selected from the group consisting of O ₂ , H ₂ , N ₂ , and Ar.

In one aspect of the present invention, the hydrophilization treatment is performed in a range in which the adhesion force between the metal nanowire and the curable polymer resin is A ₁ , and the adhesion force between the release layer and the metal nanowire is A ₂ , . ≪ / RTI >

[Formula 3]

A ₁ < A ₂

In one aspect of the present invention, the mask may be made of a siloxane-based polymer, a silicone rubber, or a metal material.

In one embodiment of the present invention, the concave-convex structure may be such that the width of the concave portion and the width of the convex portion are larger than the size of the metal nanowire.

In one aspect of the present invention, the surface treatment may be plasma, ultraviolet-ozone, electron beam or ion beam treatment.

In one embodiment of the present invention, the hydrophobic polymer resin may be an olefin resin, a vinyl resin, a polyester resin, a polyurethane resin, a polyamide resin, a silicone resin, a cellulose resin, a polyimide resin, , A polyether sulfone type resin, a polyacetal type resin, and a poly (meth) acrylic type resin.

In one embodiment of the present invention, the curable polymer resin may be selected from an ultraviolet curable polymer resin, a thermosetting polymer resin, a room temperature moisture curing polymer resin, and an infrared curing polymer resin.

In one aspect of the present invention, the substrate may be any one selected from silicon, quartz, glass, silicon wafer, polymer, metal, and metal oxide.

In one embodiment of the present invention, the metal nanowire is made of a metal such as silver (Ag), copper (Cu), aluminum (Al), gold (Au), platinum (Pt), nickel (Ni), titanium And may have a diameter of 10 to 50 nm, a length of 10 to 50 μm, and an aspect ratio of 500 to 800.

In one embodiment of the present invention, the metal nanowire solution may be one wherein 0.1 to 1.0 wt% of metal nanowires are dispersed in one or two or more solvents selected from purified water, ethanol, isopropyl alcohol, and butyl carbitol.

In one embodiment of the present invention, the application may be selected from spin coating, bar coating, roll to roll coating.

Another aspect of the present invention is a method for fabricating a polymer film, comprising the steps of: providing a polymer film and a metal nanowire layer, wherein the metal nanowire layer is patterned according to the shape of the mask, And the uneven structure is integrally formed on the surface of the metal nanowire layer.

In one aspect of the structure-integrated flexible transparent electrode of the present invention, the structure-integrated flexible transparent electrode is one used for a solar cell, an organic light emitting diode (OLED), a surface lighting, an e-paper, an e-book, .

Hereinafter, each step of the present invention will be described in more detail.

The step a) is for forming a concave-convex structure on the surface, and the release layer is used for forming a concave-convex structure at the same time while weakening the adhesion force between the substrate and the metal nanowire. The release layer is formed by using a resin having excellent releasability from the metal nanowire and the curable polymer resin so as to be easily released by applying a physical force using a finger or a cotton swab when separating the polymer film in which the metal nanowires are embedded desirable.

In one embodiment of the present invention, the release layer may be formed by applying a hydrophobic polymer resin, and spin coating, bar coating, roll-to-roll coating or the like may be used as a coating method.

In one aspect of the invention, the degree of hydrophobicity may be measured by the contact angle to water. The surface of the release layer made of the hydrophobic polymer resin may have a contact angle with respect to water specifically 65 ° or more, more specifically 65 to 85 °.

In one embodiment of the present invention, the release layer formed of the hydrophobic polymer resin is preferably non-compatible with the polymer film formed of the curable polymer resin. In the present invention, the concept of the solubility parameter of the polymer Respectively.

Specifically, the solubility parameter δ ₁ of the hydrophobic polymer resin and the solubility constant δ ₂ of the curable polymer resin The difference value Δδ in the following formula 1 may satisfy the following formula 2.

[Formula 1]

Δδ = | δ ₂ - δ ₁ |

[Formula 2]

2 &lt; / =

In the above formula (2) units are J ^{1/2 /} cm ^2/3.

The solubility constants can be calculated according to the method described by Hoftyzer-Van Krevelen of Van Krevelen, "Properties of Polymers: Their Correlation with Chemical Structure", 3rd Ed, Elsevier, 1990.

More specifically, the delta of the formula 2 may be 2 to 10, more preferably 3 to 10. The larger the value of DELTA delta is, the more the non-compatibility is increased and the releasability is further improved.

In one embodiment of the present invention, examples of the hydrophobic polymer resin include an olefin resin, a vinyl resin, a polyester resin, a polyurethane resin, a polyamide resin, a silicone resin, a cellulose resin, a polyimide resin, But are not limited to, one or more kinds of copolymers selected from the group consisting of a phthalic resin, a polyether sulfone resin, a polyacetal resin and a poly (meth) acrylic resin. More specifically, examples thereof include polyolefins such as polyethylene, polypropylene, poly 4-methyl 1-pentene, polyvinyl chloride, polystyrene, polybutadiene, polyvinylacetate, polychloroprene, polyvinylidene chloride, polyvinyl butyral, Polyacrylate, polyurethane, nylon 6, nylon 66, silicone rubber, ethyl cellulose, polysulfone, polyacetal, polyacrylonitrile, polyimide and the like can be used , But is not limited thereto. The present invention can be used without limitation as long as it is a resin having non-compatibility with the curable polymer resin having a releasing property with the metal nanowire and used in the polymer film in which the metal nanowire is embedded.

In one embodiment of the present invention, the substrate may be silicon, quartz, glass, silicon wafer, polymer, metal, and metal oxide, but is not limited thereto. The polymer substrate may be a film substrate such as polyethylene terephthalate, polycarbonate, polyimide, polyethylene naphthalate, cycloolefin polymer, or the like. It is not. From the standpoint of ease of manufacture and supply, glass or silicon wafers may be used.

In one embodiment of the present invention, the method of forming the concavo-convex structure in the release layer may be various. Specifically, for example, after the curable polymer resin is coated on the substrate, the concavo- A resin or a hydrophobic polymer resin may be coated on a substrate and then imprinted with a mold. Here, the concavo-convex structure by imprinting can be manufactured by injection from a mold, or by a method such as soft lithography, but is not limited thereto. In addition, the size of the irregularities is not limited, and the size of the irregularities is preferably larger than that of the metal nanowires to maintain the embedded state of the metal nanowires, more preferably several micrometers. Specifically, it may be, for example, 1 to 100 탆, but is not limited thereto. Further, the shape of the concavities and convexities is not limited, and various shapes such as a wrinkle structure and a leaf structure are possible.

More specifically, the method of forming the concavo-convex structure on the release layer can be manufactured by the following two methods, but is not limited thereto.

In the first aspect, the substrate is cured by curing the curable polymer resin, and then the substrate is subjected to a surface treatment or an imprinting process to form a concavo-convex structure on the surface, and then a hydrophobic polymer resin is applied on the concavo- Is formed.

The curable polymer resin used in the step a) of the first embodiment may be the same or different from the curable polymer resin used in the step c), and may be selected from the group consisting of an ultraviolet curable polymer resin, a thermosetting polymer resin, a room temperature moisture curable polymer resin, Curable polymer resin and the like can be used.

The curable polymer resin may be applied by spin coating, bar coating, roll-to-roll coating or the like, but the present invention is not limited thereto and can be modified using known techniques. The coating thickness of the curable polymer resin is not limited and may be determined according to the width of the concavo-convex structure to be formed. Specifically, it may be, for example, 100 to 500 μm, more preferably 300 to 400 μm, .

The surface treatment process for forming the concavo-convex structure may be performed by plasma treatment, ultraviolet-ozone, electron beam or ion beam treatment using one or more gases selected from the group consisting of O ₂ , H ₂ , N ₂ and Ar . Further, the method may further include the step of further curing the curable polymer resin so that there is no deformation of the structure after forming the uneven structure through the surface treatment step as necessary.

The imprinting process for forming the concavo-convex structure may be a process in which a mold having a concavo-convex structure is manufactured in advance, the mold is placed on a curable polymer resin coated on a substrate, have.

Although the mold used in the imprinting process is not limited, it is possible to form a concavo-convex structure on the surface through a surface treatment process or an imprint process by coating the substrate with a curable polymer resin, And then heat-treating the siloxane-based polymer. Further, it may be a mold having a microlens structure manufactured by a hydroforming method, a shrinking method or the like. In addition, molds made of various materials such as rubber, polymer, and metal can be used.

Next, a hydrophobic polymer resin is coated on the curable polymer resin layer having the unevenness formed thereon and cured to form a release layer having a concavo-convex structure on its surface. More specifically, when polymethyl methacrylate is used as the hydrophobic polymer resin, And then heat-treated at 170 to 190 ° C for 30 seconds to 1 minute to form a release layer. It is to be understood that this is for illustrative purposes only, and is not intended to be limiting. The thickness of the releasing layer imparts releasability between the metal nanowire and the substrate, facilitates the formation of the concavo-convex structure, and at the same time, when the polymer film having the metal nanowires embedded therein is peeled off, It does not. Considering such characteristics, it may be 200 to 500 mu m, preferably 380 to 420 mu m, but is not limited thereto.

In one embodiment of the present invention, more specifically, a curable polymer resin is coated on a glass or silicon wafer substrate and cured. Then, O ₂ gas is injected at 2 to 20 sccm, plasma treatment is performed at a power of 15 W to 75 W for 20 to 40 seconds And may be formed by forming a concave-convex structure and spin-coating polymethyl methacrylate thereon, but the present invention is not limited thereto. In spin coating, polymethylmethacrylate may be applied over the entire surface of the substrate using a micropipette, followed by spin coating at 2000 to 3000 rpm for 30 to 40 seconds.

The second aspect of forming the concavo-convex structure on the release layer is that the hydrophobic polymer resin is applied to the substrate, and the mold having the concavo-convex structure and the siloxane polymer is closely contacted and dried before the hydrophobic polymer resin is dried , And the mold may be removed to form a concavo-convex structure.

In this case, the mold can be made of a variety of molds manufactured by various methods as described above. For example, the mold may be formed by coating a substrate with a curable polymer resin, curing the substrate, An irregular structure may be formed on the surface through an imprinting process, and then a siloxane polymer may be coated on the irregular structure and then heat-treated.

Next, the step (b) of the present invention will be described in more detail.

In the step b), a metal nanowire coating layer is formed. The metal nanowire solution may be applied and then dried. In the step b) of the present invention, since the metal nanowire solution is coated on the release layer having the concavo-convex structure on the surface, the metal nanowire coating layer having the concavo-convex structure formed on the surface along the concavo- .

In one embodiment of the present invention, the metal nanowire solution is added to one or two or more solvents selected from purified water, ethanol, isopropyl alcohol and butyl carbitol in an amount of 0.1 to 1.0 wt%, more preferably 0.2 to 0.8 wt% But may not be limited thereto.

In one embodiment of the present invention, the metal nanowire is made of a metal such as silver (Ag), copper (Cu), aluminum (Al), gold (Au), platinum (Pt), nickel (Ni), titanium , But is not limited thereto.

In one aspect of the present invention, since the transmittance and the electrical conductivity change when the length of the metal nanowire changes, it is preferable to select the length and the diameter in consideration of the transmittance and the sheet resistance depending on the purpose of use. More specifically, the metal nanowires may have a diameter of 10 to 50 nm, a length of 10 to 50 μm, and an aspect ratio of 500 to 800, but the present invention is not limited thereto.

In one embodiment of the present invention, the application of the metal nanowire solution may be performed by a method such as spin coating, bar coating, roll to roll coating, and the like, but is not limited thereto.

In one embodiment of the present invention, the thickness of the metal nanowire coating layer may be 20 to 90 nm, more preferably 40 to 70 nm, although not limited.

More specifically, the metal nanowire solution is spin-coated by spin coating at 500 to 700 rpm for 30 seconds to 2 minutes and then heat-treated at 80 to 110 ° C for 30 seconds to 1 minute to form a metal nanowire coating layer . At this time, when the metal nanowire solution is slowly applied, it may remain unevenness, so it is preferable to uniformly apply the coating solution by controlling the application time and the spin coating speed. In addition, since the density of the metal nanowires may vary depending on the application speed during spin coating, it is preferable to adjust the spin coating speed so that the density of the metal nanowires can be adjusted according to the application of the transparent electrode.

Next, step (c) of the present invention will be described in more detail.

In the step c), since the metal nanowire is impregnated to lower the surface roughness and the flexible transparent electrode having a concavo-convex structure on the surface is formed, the curable polymer resin having excellent compatibility with the metal nanowire and capable of impregnating the metal nanowire To thereby form a concavo-convex structure on the surface along the concavo-convex structure formed in the release layer by impregnating the metal nanowire in the polymer film.

In one embodiment of the present invention, the curable polymer resin is preferably a flexible resin, and at the same time, it is preferable to use a hydrophobic polymer resin used in the release layer and a resin having an incompatible solubility. More specifically, And &lt; RTI ID = 0.0 &gt; 2. &Lt; / RTI &gt;

[Formula 1]

Δδ = | δ ₂ - δ ₁ |

In the above formula 1 δ ₁ is Is the solubility parameter of the hydrophobic polymer resin, and? ₂ is the solubility constant of the curable polymer resin.

[Formula 2]

2 &lt; / =

In the above formula (2) units are J ^{1/2 /} cm ^2/3.

From the viewpoint of forming a transparent electrode, it is more preferable that the total light transmittance is 80 to 99%, but it is not limited thereto.

In one embodiment of the present invention, the curable polymer resin may be an ultraviolet curable polymer resin, a thermosetting polymer resin, a room temperature moisture curing polymer resin, an infrared curing polymer resin, or the like, but is not limited thereto.

In one embodiment of the present invention, the curable polymer resin is preferably in the form of a liquid in order to smoothly form a surface layer by embedding metal nanowires not fixed to the release layer. The liquid phase is preferably a polymeric resin in which the polymer resin is dissolved in water or a solvent, And the polymer resin itself is a liquid having a viscosity.

In one embodiment of the present invention, the curable polymer resin does not inhibit the physical properties of the release layer, does not inhibit the physical properties of the metal nanowire, and uses an ultraviolet curable polymer in order to form a polymer film having excellent transmittance . The ultraviolet curable polymer is not limited as long as it is a resin which is cured to a solid state when exposed to ultraviolet light having a wavelength of 280-350 nm, and more preferably a transparent colorless liquid. In this respect, Norland Optical Adhesive series from Norland Products can be used as an example of commercialization from this viewpoint. Specifically, for example, NOA60, NOA61, NOA63, NOA65, NOA68, NOA68T, NOA71, NOA72, NOA73, NOA74, NOA75, NOA76 and NOA78 , NOA81, NOA83H, NOA84, NOA85, NOA85V, NOA86, NOA86H, NOA87, NOA88, NOA89, and the like.

In one embodiment of the present invention, the thickness of the polymer film formed by applying the curable polymer resin is not limited, but may be 50 to 2,000 m, more preferably 100 to 300 m. In the above range, a flexible transparent electrode in the form of a polymer film having a concavo-convex structure formed on its surface by embedding metal nanowires on the surface can be formed.

Next, in the step d), the polymer film having the metal nanowires embedded therein is separated from the release layer to produce a flexible transparent electrode having a metal nanowire layer having a concavo-convex structure on the surface thereof. Since the polymer film is incompatible with the hydrophobic polymer resin used in the release layer, the polymer film can be easily pushed out by applying a physical force, that is, by using a finger or a cotton swab.

Next, the third and fourth aspects of the present invention will be described in detail.

In the third and fourth aspects of the present invention, in the first and second aspects, a concavo-convex structure is formed on the surface and a pattern is formed on the metal nanowire layer. In the third and fourth aspects, , A mask is placed and a plasma or ultraviolet-ozone treatment is performed to add a process of hydrophilizing the portion having no mask.

More specifically, in the third and fourth aspects, the step a) is for forming a concave-convex structure on the surface while simultaneously forming a pattern on the metal nanowire coating layer. The release layer is used to weaken the adhesion between the substrate and the metal nanowire while simultaneously forming a concave-convex structure. The release layer is characterized in that the adhesion strength is controlled by hydrophilizing to form a pattern of the metal nanowire. When separating the polymer film in which the metal nanowires are embedded, it is preferable to use a resin having excellent releasability from the metal nanowire and the curable polymer resin so as to easily release the polymer film by applying a physical force using a finger or a cotton swab.

Specifically, for example, a mask may be placed on a release layer on which a concave-convex structure made of a hydrophobic polymer resin is formed, and plasma or ultraviolet-ozone treatment may be performed to hydrophilize the maskless portion.

The adhesion between the release layer and the metal nanowire is greatly improved in the portion where the mask is not located by plasma, ultraviolet-ozone, electron beam, or ion beam treatment, and the metal nanowire is already fixed on the release layer or the hydrophobic polymer substrate When the polymer film is separated, the metal nanowires excluding the metal nanowires fixed to the release layer or the hydrophobic polymer substrate are separated in a state of being buried, so that a pattern is formed. That is, the pattern of the metal nanowire coating layer is determined according to the pattern of the mask.

In addition, since the polymer film is incompatible with the hydrophobic polymer resin or the hydrophobic polymer substrate used in the release layer, physical force can be applied thereto, that is, it can be easily pushed out by using a finger or a cotton swab.

In one aspect of the present invention, the mask is used for forming a metal nanowire pattern, and the mask is formed in a pattern shape to be formed on the transparent electrode. The material of the mask may be, for example, a siloxane-based polymer, a silicone rubber, or a metal material, but not limited thereto, and any mask used for the plasma treatment or ultraviolet-ozone treatment may be used without limitation. More specifically, the siloxane-based polymer may be a polydimethylsiloxane (PDMS) from the viewpoint of preventing the plasma from penetrating through the strong contact with the release layer, but the present invention is not limited thereto. In addition, from the viewpoint of forming a fine pattern, it may be a metal, and the kind of the metal is not limited.

The mask may be adhered to the release layer, or may be spaced a distance from the release layer.

By placing the mask on the release layer and subjecting the surface of the release layer to plasma or ultraviolet-ozone treatment, the surface of the release layer is oxidized to have hydrophilicity, so that the adhesion with the metal nanowire can be further improved. The present invention is advantageous in that a simple process and a fine pattern can be easily formed by a method of forming a pattern by controlling the adhesive force.

In one embodiment of the present invention, the adhesive force of the release layer can be controlled by adjusting the pressure, power and time during the plasma treatment or ultraviolet-ozone treatment. More specifically, it is preferable that the adhesive force (A ₁ ) between the metal nanowire and the curable polymer resin and the adhesive force (A ₂ ) between the release layer and the metal nanowire satisfy the following formula (3).

[Formula 3]

A ₁ < A ₂

When the curable polymer resin of the step c) is applied in the range satisfying the formula 3, the metal nanowires not subjected to plasma treatment or ultraviolet-ozone treatment have a strong adhesive force with the curable polymer resin, Impregnated with the metal nanowires can form a smooth surface in which the metal nanowires do not protrude on the surface and can be formed into a smooth surface. In this case, since the hydrophobic resin used in the release layer is incompatible with the metal nanowire, To form a polymer film, and at the same time, release from the release layer easily. Further, the portion without the mask is hydrophilized by plasma treatment or ultraviolet-ozone treatment, and the metal nanowires are fixed on the surface of the release layer, so that they remain on the release layer without peeling together when the polymer film is peeled off.

That is, the release layer has a weak adhesive force between the release layer and the metal nanowire at the portion where the mask is located, and the adhesion between the release layer and the metal nanowire is improved by the plasma or ultraviolet-ozone treatment at the portion without the mask The metal nanowires are fixed to the release layer. In addition, when the polymer film embedded with the metal nanowires is separated in the step d), the metal nanowires strongly fixed to the release layer are not separated and remain in the release layer to form a pattern.

In one embodiment of the present invention, the plasma treatment may be one using one or more gases selected from the group consisting of O ₂ , N ₂ O, H ₂ O and C ₂ H ₅ OH, Any material capable of oxidizing and hydrophilizing the surface can be used without limitation. More specifically, for example, the plasma treatment may be performed at a pressure of 2.0 x 10 ^-1 to 8.0 x 10 ^-1 Torr, an RF power of 20 to 50 W using an O ₂ gas of 5 to 20 sccm For 5 to 30 minutes. More specifically, the treatment may be performed at a pressure of 3.9 x 10 ^-1 to 4.2 x 10 ^-1 Torr and an RF power of 20 to 30 W for 5 to 30 minutes using a gas of 8 to 15 sccm. In the above range, the adhesive strength of the release layer increases at the portion where no mask is present, and the adhesion strength with the metal nanowires is improved, so that the adhesive strength can be made stronger than the adhesion strength between the metal nanowires and the curable polymer resin.

In addition, ultraviolet-ozone treatment is a method of cutting a main chain of a polymer by ozone generated by ultraviolet ray and ultraviolet ray irradiation and forming a surface oxidation layer. By forming an oxide layer on a hydrophobic surface using ultraviolet irradiation, So that the adhesive strength can be further improved. Specifically, for example, a mercury lamp having a main wavelength of 200 to 280 nm, which is a UV-C region, is irradiated with an ultraviolet / ozone irradiator having an output of 100 to 200 mW / cm ² for 10 minutes or more, more specifically 10 Minute to 30 minutes. In this range, the contact angle of the release layer of the maskless portion is reduced to about 40 degrees or less, and the adhesion between the metal nanowire and the release layer or the hydrophobic polymer is improved, so that the metal nanowire is fixed on the release layer or the hydrophobic polymer substrate And remains on the substrate during coating and removal of the curable polymer.

Since the subsequent steps are the same as those of the first and second embodiments described above, further explanation is omitted.

Another aspect of the present invention relates to a method for manufacturing a metal nanowire including a polymer film and a metal nanowire layer, the metal nanowire layer having a pattern, a metal nanowire layer embedded in the polymer film, And the uneven structure is formed integrally with the flexible transparent electrode.

In one embodiment of the present invention, the size of the concavo-convex structure is preferably larger than the size of the metal nanowire because it is suitable for application to a solar cell, an OLED, and the like, while preventing the nanowire from protruding to the surface. More preferably a few micrometers in size, but is not limited thereto. In addition, the shape is not limited because it can be changed for various purposes.

In one aspect of the present invention, the transparent electrode may be one used for a solar cell, an organic light emitting diode (OLED), a surface light, an e-paper, an e-book, a touch panel, or a display substrate, It is applicable to device field.

Hereinafter, the present invention will be described in more detail based on examples and comparative examples. However, the following examples and comparative examples are merely examples for explaining the present invention in more detail, and the present invention is not limited by the following examples and comparative examples.

The physical properties were measured by the following measurement methods.

1) solubility parameter

The solubility constants were calculated according to the method described by Hoftyzer-Van Krevelen of Van Krevelen ("Properties of Polymers: Their Correlation with Chemical Structure", 3rd Ed, Elsevier, 1990).

2) Contact angle

Contact angle of distilled water was measured at constant temperature and humidity condition (20 ° C, 65% RH) using a contact angle meter of KRUSS EasyDrop FM 40 model. More specifically, a drop of 20 mg was dropped on the surface of the sample using a microsyringe, and the contact angle was measured using a tangent method in software. The contact angle was measured five times or more and the average value was obtained.

3) Surface roughness

Surface roughness was analyzed using AFM (Atomic force microscopy) equipment.

4) Transmittance (%)

The transmittance of the fabricated flexible transparent electrode was measured according to ASTM D1003 and expressed as a percentage. The light transmittance was measured in the visible light region using a UV-Visible-NIR spectrometer (Agilent, Cary-5000).

5) Surface resistance (Ω / sq.)

The surface resistivity (Ω / sq) of the sheet resistance of the manufactured flexible transparent electrode was measured according to ASTM D257 under conditions of 23 ° C. and 60% RH.

6) Thickness

The film thickness of the transparent electrode prepared in the examples was measured.

The film thickness was measured using a vernier caliper against a 1 cm x 1 cm area at the center of the sample.

[Example 1]

The glass substrate was immersed in acetone, washed with an ultrasonic washing machine for 10 minutes to remove foreign substances, and then immersed in isopropyl alcohol and washed with an ultrasonic washing machine for 10 minutes to remove acetone. The glass substrate from which the acetone had been removed was placed in an oven at 100 ° C to quickly remove the remaining isopropyl alcohol to prepare a clean glass substrate.

NOA 63 (NOA63, Norland Products Inc, USA), which is a colorless liquid, was coated on the dried glass substrate by optical adhesive of Norland Co., and then spin-coated at 500 rpm for 15 seconds and 3000 rpm for 60 seconds in two steps. Then cured at 365 nm UV and cured until the total UV energy reached 1.5 J. At this time, the coating thickness of NOA 63 was 30 탆.

Subsequently, a substrate coated with NOA 63 was submerged in the plasma chamber, and a vacuum was formed at a low pressure and oxygen gas of 8 sccm was injected. Thereafter, it was treated with 45 W of plasma for 30 seconds to form a concave-convex structure on the NOA 63 layer. NOA 63 with irregular structure was further cured at 365 nm UV for 30 minutes so that the structure was not deformed.

Thereafter, 300 쨉 l of polymethyl methacrylate (495 PMMA A2, 495 PMMA A2, manufactured by Micro CHEM) was coated on the entire surface using a micropipette, and then spin-coated at 3000 rpm for 30 seconds. It was confirmed that the shape of the acrylate was controlled along the concavo-convex structure formed on the substrate, followed by drying at 180 ° C for 1 minute to form a release layer.

500 ㎕ of silver nanowire solution was rapidly applied to the entire surface of the substrate on which the release layer having the concavo-convex structure was formed by using a micropipette, and then spin-coated for 1 minute at a rotation speed of the spin coater of 600 rpm. Dried for a minute to evaporate the solvent, and the adhesion between silver nanowires was increased to form a network to form a silver nanowire coating layer.

At this time, the silver nanowire solution used was a silver nanowire dispersion product synthesized by Nanopics Co., Ltd. The silver nanowire having a diameter of 35 ± 5 nm, a length of 20 ± 5 μm and an aspect ratio of 500 or more was dissolved in purified water ) At a specific gravity of 0.3 wt%.

1 g of the curable polymer resin was applied on the silver nanowire coating layer on the entire surface, and the bubbles were removed, followed by spin coating at a speed of 500 rpm for 1 minute. At this time, the curable polymer resin used was NOA 63 (NOA63, Norland Products Inc, USA), which is a colorless liquid, as optical adhesive of Norland Co. NOA 63 requires about 4.5 J / sq of energy for curing and has a viscosity of 2000 cPs at 25 ° C and has a refractive index of 1.56 when cured, an elongation of 6%, a modulus of elasticity of 240000 psi, a tensile strength of 5000 psi, .

After the spin coating, the polymer film was irradiated with 5.0 J / sq of ultraviolet ray for 15 minutes.

The completely cured polymer film was separated from the substrate. The silver nanowire having weakened adhesion to the substrate by the release layer was embedded in the curable polymer resin, so that a flexible transparent electrode having a concavo-convex structure as shown in FIG. 1 was produced on the surface.

Also, as shown in FIG. 4, it was confirmed that the dispersed light was further improved compared to when the concavo-convex structure was not formed (indicated by W / O wrinkle) by forming the concave-convex structure (indicated with wrinkle).

[Example 2]

The glass substrate was immersed in acetone, washed with an ultrasonic washing machine for 10 minutes to remove foreign substances, and then immersed in isopropyl alcohol and washed with an ultrasonic washing machine for 10 minutes to remove acetone. The glass substrate from which the acetone had been removed was placed in an oven at 100 ° C to quickly remove the remaining isopropyl alcohol to prepare a clean glass substrate.

NOA 63 (NOA63, Norland Products Inc, USA), which is a colorless liquid, was coated on the dried glass substrate by optical adhesive of Norland Co., and then spin-coated at 500 rpm for 15 seconds and 3000 rpm for 60 seconds in two steps. Then cured at 365 nm UV and cured until the total UV energy reached 1.5 J. At this time, the coating thickness of NOA 63 was 30 탆.

Subsequently, a substrate coated with NOA 63 was submerged in the plasma chamber, and a vacuum was formed at a low pressure and oxygen gas of 8 sccm was injected. Thereafter, the substrate was treated with 45 W of plasma for 30 seconds to form a concave-convex structure on the NOA 63 layer. NOA 63 with irregular structure was further cured at 365 nm UV for 30 minutes so that the structure was not deformed.

Thereafter, 300 쨉 l of polymethyl methacrylate (495 PMMA A2, 495 PMMA A2, manufactured by Micro CHEM) was coated on the entire surface using a micropipette, and then spin-coated at 3000 rpm for 30 seconds. It was confirmed that the shape of the acrylate was controlled along the concavo-convex structure formed on the substrate, followed by drying at 180 ° C for 1 minute to form a release layer.

Polydimethylsiloxane (PDMS) blocks were well adhered to the substrate having the release layer having the concavo-convex structure formed thereon as a mask, and subjected to a plasma treatment to perform hydrophilization treatment. The plasma treatment was carried out at 10 sccm of O ₂ gas at a pressure of 3.9 × 10 ^-1 Torr and an RF power of 30 W for 1 minute. The contact angle of the plasma treated portion after the plasma treatment was 40 DEG.

The mask was removed and 500 ㎕ of silver nanowire solution was quickly applied to the entire surface using a micropipette. The spin speed of the spin coater was adjusted to 600 rpm by spin coating for 1 minute and drying at 100 캜 for 1 minute to remove the solvent Evaporated and the adhesion between the silver nanowires was increased to form a network to form a silver nanowire coating layer.

At this time, the silver nanowire solution used was a silver nanowire dispersion product synthesized by Nanopics Co., Ltd. The silver nanowire having a diameter of 35 ± 5 nm, a length of 20 ± 5 μm and an aspect ratio of 500 or more was dissolved in purified water ) At a specific gravity of 0.3 wt%.

1 g of the curable polymer resin was applied on the silver nanowire coating layer on the entire surface, and the bubbles were removed, followed by spin coating at a speed of 500 rpm for 1 minute. At this time, the curable polymer resin used was NOA 63 (NOA63, Norland Products Inc, USA), which is a colorless liquid, as optical adhesive of Norland Co. NOA 63 requires about 4.5 J / sq of energy for curing and has a viscosity of 2000 cPs at 25 ° C and has a refractive index of 1.56 when cured, an elongation of 6%, a modulus of elasticity of 240000 psi, a tensile strength of 5000 psi, .

After the spin coating, the polymer film was irradiated with 5.0 J / sq of ultraviolet ray for 15 minutes.

The completely cured polymer film was separated from the substrate, and it was confirmed that a silver nanowire having weak adhesion to the substrate by the release layer was embedded in the curable polymer resin to form a pattern, and a flexible transparent electrode having a concavo-convex structure on its surface was produced . The pattern structure is shown in Fig.

The properties of the prepared transparent electrode were measured and are shown in Table 1 below.

[Example 3]

The same procedure as in Example 2 was carried out except that a hydrophilic treatment was performed using an ultraviolet / ozone irradiator instead of the plasma treatment. Ultraviolet irradiation was carried out with a mercury lamp for surface treatment having a dominant wavelength in the UV-C region at a power of 110 mW / cm ² for 30 minutes. The contact angle of the release layer after the ultraviolet / ozone irradiation treatment was 35 °.

As a result, it was confirmed that the silver nanowire was embedded in the curable polymer resin and patterned, and a flexible transparent electrode having a concavo-convex structure was formed on the surface.

The properties of the prepared transparent electrode were measured and are shown in Table 1 below.

[Example 4]

A transparent electrode was prepared in the same manner as in Example 2 except that a patterned metal mask was used instead of the polydimethylsiloxane (PDMS) block in Example 2 above. It was confirmed that a flexible transparent electrode having a patterned silver nanowire on its surface and formed with a concave-convex structure was produced.

The properties of the prepared transparent electrode were measured and are shown in Table 1 below.

[Example 5]

Example 1 In the release layer has a solubility parameter of 19 J ^{1/2 /} cm ^2/3 of polymethyl methacrylate using the rate, curable polymer resin with a solubility parameter of the 22.46 J ^{1/2 /} cm ^2/3 of Penta Except that 0.1 g of pentaerythritol propoxylate triacrylate (Aldrich, USA) was applied by a spin coating method, and then the polyethylene terephthalate film was raised and cured, To prepare a transparent electrode. The curable polymer resin was spin-coated in the same manner as in Example 1, and cured by irradiating ultraviolet rays for 40 minutes.

As a result, it was confirmed that the silver nanowire was embedded in the curable polymer resin to produce a flexible transparent electrode having a concavo-convex structure on its surface.

[Example 6]

The same procedure as in Example 1 was repeated except that the release layer in Example 1 was a polymethyl methacrylate having a solubility parameter of 19 and the curable polymer resin was a UV curable epoxy resin having a solubility parameter of 21, . The curable polymer resin was spin-coated in the same manner as in Example 1, and cured by irradiating ultraviolet rays for 40 minutes.

As a result, it was confirmed that the silver nanowire was embedded in the curable polymer resin to produce a flexible transparent electrode having a concavo-convex structure on its surface.

[Example 7]

A mold having a physical structure for imprinting was prepared using polydimethylsiloxane (PDMS). For the preparation of PDMS molds, monomers and initiators of Sylgard 184 elastomer kit (Dow Corning Corporation, USA) were first mixed at a weight ratio of 10: 1. The master pattern was fixed on the bottom of the Petri dish and the prepared PDMS was poured. The PDMS was then cured at 80 ° C for 24 hours, and the cured PDMS was separated from the substrate to complete the mold.

Then, the glass substrate was immersed in acetone, washed with an ultrasonic washing machine for 10 minutes to remove foreign substances, and then immersed in isopropyl alcohol and washed with an ultrasonic washing machine for 10 minutes to remove acetone. The glass substrate from which the acetone had been removed was placed in an oven at 100 ° C to quickly remove the remaining isopropyl alcohol to prepare a clean glass substrate.

On the dried glass substrate, a colorless liquid NOA 63 (NOA63, Norland Products Inc, USA) was coated on the entire surface with Norland Optical Adhesive, and the prepared PDMS mold was covered and cured at 365 nm UV for 15 minutes to imprint the structure. The PDMS was removed after curing and further cured at 365 nm UV for 30 minutes for complete curing of NOA 63. Thereafter, 300 쨉 l of polymethyl methacrylate (495 PMMA A2, 495 PMMA A2, manufactured by Micro CHEM) was coated on the entire surface using a micropipette, and then spin-coated at 3000 rpm for 30 seconds. It was confirmed that the shape of the acrylate was controlled along the concavo-convex structure formed on the substrate, followed by drying at 180 ° C for 1 minute to form a release layer.

500 ㎕ of silver nanowire solution was rapidly applied to the entire surface of the substrate on which the release layer having the concavo-convex structure was formed by using a micropipette, and then spin-coated for 1 minute at a rotation speed of the spin coater of 600 rpm. Dried for a minute to evaporate the solvent, and the adhesion between silver nanowires was increased to form a network to form a silver nanowire coating layer.

At this time, the silver nanowire solution used was a silver nanowire dispersion product synthesized by Nanopics Co., Ltd. The silver nanowire having a diameter of 35 ± 5 nm, a length of 20 ± 5 μm and an aspect ratio of 500 or more was dissolved in purified water ) At a specific gravity of 0.3 wt%.

1 g of the curable polymer resin was applied on the silver nanowire coating layer on the entire surface, and the bubbles were removed, followed by spin coating at a speed of 500 rpm for 1 minute. At this time, the curable polymer resin used was NOA 63 (NOA63, Norland Products Inc, USA), which is a colorless liquid, as optical adhesive of Norland Co. NOA 63 requires about 4.5 J / sq of energy for curing and has a viscosity of 2000 cPs at 25 ° C and has a refractive index of 1.56 when cured, an elongation of 6%, a modulus of elasticity of 240000 psi, a tensile strength of 5000 psi, .

After the spin coating, the polymer film was irradiated with 5.0 J / sq of ultraviolet ray for 15 minutes.

The fully cured polymer film was separated from the substrate, and it was confirmed that the silver nanowire having weakened adhesion to the substrate by the release layer was embedded in the curable polymer resin to produce a flexible transparent electrode having a concavo-convex structure on the surface.

[Example 8]

A PDMS mold was fabricated through the same process as in Example 7. Then, the glass substrate was immersed in acetone, washed with an ultrasonic washing machine for 10 minutes to remove foreign substances, and then immersed in isopropyl alcohol and washed with an ultrasonic washing machine for 10 minutes to remove acetone. The glass substrate from which the acetone had been removed was placed in an oven at 100 ° C to quickly remove the remaining isopropyl alcohol to prepare a clean glass substrate.

300 쨉 l of polymethylmethacrylate (Micro CHEM, 495 PMMA A2, weight average molecular weight: 495000 g / mol) was coated on the dried glass substrate using a micropipette, and then spin-coated at 3000 rpm for 30 seconds. Then, the prepared release layer was imprinted on the release layer to form a concave-convex structure, followed by drying at 180 DEG C for 1 minute to form a release layer.

500 ㎕ of silver nanowire solution was rapidly applied to the entire surface of the substrate on which the release layer having the concavo-convex structure was formed by using a micropipette, and then spin-coated for 1 minute at a rotation speed of the spin coater of 600 rpm. Dried for a minute to evaporate the solvent, and the adhesion between silver nanowires was increased to form a network to form a silver nanowire coating layer.

At this time, the silver nanowire solution used was a silver nanowire dispersion product synthesized by Nanopics Co., Ltd. The silver nanowire having a diameter of 35 ± 5 nm, a length of 20 ± 5 μm and an aspect ratio of 500 or more was dissolved in purified water ) At a specific gravity of 0.3 wt%.

1 g of the curable polymer resin was applied on the silver nanowire coating layer on the entire surface, and the bubbles were removed, followed by spin coating at a speed of 500 rpm for 1 minute. At this time, the curable polymer resin used was NOA 63 (NOA63, Norland Products Inc, USA), which is a colorless liquid, as optical adhesive of Norland Co. NOA 63 requires about 4.5 J / sq of energy for curing and has a viscosity of 2000 cPs at 25 ° C and has a refractive index of 1.56 when cured, an elongation of 6%, a modulus of elasticity of 240000 psi, a tensile strength of 5000 psi, .

After the spin coating, the polymer film was irradiated with 5.0 J / sq of ultraviolet ray for 15 minutes.

The fully cured polymer film was separated from the substrate, and it was confirmed that the silver nanowire having weakened adhesion to the substrate by the release layer was embedded in the curable polymer resin to produce a flexible transparent electrode having a concavo-convex structure on the surface.

Release layer contact angle
(°) Contact angle (°) after hydrophilization treatment Transmittance Sheet resistance Film thickness Example 2 70 40 83.9% 30.5 Ω / □ 200μm Example 3 70 35 84.7% 28.8Ω / □ 200μm Example 4 70 35 84.7% 28.8Ω / □ 200μm

Claims (18)

a) curing a substrate with a curable polymer resin, curing the substrate, forming a physical uneven structure for controlling the optical path on the surface through a surface treatment process or an imprint process, and then forming a hydrophobic polymer resin on the uneven structure Thereby forming a release layer having a concavo-convex structure;
b) applying a metal nanowire solution to the entire surface of the release layer and then drying to form a metal nanowire coating layer;
c) coating the entire surface of the metal nanowire coating layer with a curable polymer resin and curing the metal nanowire coating to produce a polymer film having the metal nanowires embedded therein; And
d) separating the polymer film embedded with the metal nanowires from the release layer to produce a flexible transparent electrode having a metal nanowire layer having a physical irregular structure on the surface for optical path control;
Wherein the hydrophobic polymer resin and the curable polymer resin are non-compatible with each other. a) a step of applying a hydrophobic polymer resin to the substrate and drying the same before the hydrophobic polymer resin is dried in a state in which a mold made of a siloxane polymer having physical irregularities for optical path control is in close contact with the mold, Forming a release layer on which the concavo-convex structure is formed;
b) applying a metal nanowire solution to the entire surface of the release layer and then drying to form a metal nanowire coating layer;
c) applying a curable polymer resin on the metal nanowire coating layer and curing the polymer nanofibers to produce a polymer film having embedded metal nanowires; And
d) separating the polymer film embedded with the metal nanowires from the release layer to produce a flexible transparent electrode having a physical uneven structure for optical path control on the surface;
Wherein the hydrophobic polymer resin and the curable polymer resin are non-compatible with each other. 3. The method of claim 2,
The mold of step a) may be formed by coating a substrate with a curable polymer resin and curing the substrate, forming a concavo-convex structure on the surface through a surface treatment process or imprint process, applying a siloxane polymer on the concavo- Wherein the transparent electrode is formed by heat treatment. 3. The method according to claim 1 or 2,
The solubility parameter δ ₁ of the hydrophobic polymer resin and the solubility constant δ ₂ of the curable polymer resin And a difference value Δδ of the following formula (1) satisfies the following formula (2).
[Formula 1]
Δδ = | δ ₂ - δ ₁ |
[Formula 2]
2 &lt; / =
In the above formula 2, the unit is J ^1/2 / cm ^2/3 . 3. The method according to claim 1 or 2,
In the step a), after forming a release layer having a concavo-convex structure on the substrate,
Placing a mask on the release layer and performing a hydrophilization treatment to hydrophilize the maskless portion; And removing the mask, thereby forming a pattern. 6. The method of claim 5,
Wherein the contact angle of the surface of the release layer before the hydrophilization treatment with respect to water is 65 ° or more and the contact angle of the surface of the release layer after the hydrophilization treatment with water is 50 ° or less. 6. The method of claim 5,
Wherein the hydrophilic treatment is plasma, ultraviolet-ozone, electron beam or ion beam treatment. 8. The method of claim 7,
Wherein the plasma or ion beam treatment uses one or more gases selected from the group consisting of O ₂ , H ₂ , N ₂ and Ar. 6. The method of claim 5,
Wherein the hydrophilization treatment is carried out in a range that the adhesion force between the metal nanowire and the curable polymer resin is A ₁ and the adhesion force between the release layer and the metal nanowire is A ₂ , A method of manufacturing a flexible transparent electrode.
[Formula 3]
A ₁ < A ₂ 6. The method of claim 5,
Wherein the mask is made of a siloxane-based polymer, a silicone rubber, or a metal material. 3. The method according to claim 1 or 2,
Wherein the concave-convex structure has a width of the concave portion and a width of the convex portion larger than that of the metal nanowire. The method according to claim 1 or 3,
Wherein the surface treatment is plasma, ultraviolet-ozone, electron beam or ion beam treatment. 3. The method according to claim 1 or 2,
The hydrophobic polymer resin may be an olefin resin, a vinyl resin, a polyester resin, a polyurethane resin, a polyamide resin, a silicone resin, a cellulose resin, a polyimide resin, a polysulfone resin, A polyacetal resin, and a poly (meth) acrylic resin. 2. The method according to claim 1, 3. The method according to claim 1 or 2,
Wherein the curable polymer resin is selected from an ultraviolet curable polymer resin, a thermosetting polymer resin, a room temperature moisture curable polymer resin, and an infrared curable polymer resin. 4. The compound according to any one of claims 1 to 3,
Wherein the substrate is any one selected from the group consisting of silicon, quartz, glass, silicon wafer, polymer, metal, and metal oxide. 3. The method according to claim 1 or 2,
Wherein the metal nanowire is selected from silver (Ag), copper (Cu), aluminum (Al), gold (Au), platinum (Pt), nickel (Ni), titanium To 50 nm, a length of 10 to 50 μm, and an aspect ratio of 500 to 800. 3. The method according to claim 1 or 2,
Wherein the metal nanowire solution is prepared by dispersing 0.1 to 1.0 wt% of metal nanowires in one or more solvents selected from purified water, ethanol, isopropyl alcohol, and butyl carbitol. 3. The method according to claim 1 or 2,
Wherein the application is selected from spin coating, bar coating, and roll to roll coating.

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