KR101685069B1 - Manufacturing method of patterned flexible transparent electrode - Google Patents

Abstract

The present invention relates to a method for forming a pattern of a flexible transparent electrode and, more particularly, a method for forming a pattern of a flexible transparent electrode in which a metal nano-wire is embedded. The present invention may provide a novel method for manufacturing an electrode, which may form a pattern of a flexible transparent electrode through adjusting an adhesive force between materials using a plasma process, an ultraviolet-ozone process, an electron beam process or an ion beam process. Further, the present invention may manufacture a flexible transparent electrode having a pattern through a simpler process than the conventional method using photolithography. Further, the present invention does not require high-price equipment, has a simple process, and easily adjust a line width of the pattern as compared with a method for forming a pattern using schemes such as a gravure offset, gravure printing, and inkjet printing. In the flexible transparent electrode that is manufactured by the manufacturing method of the present invention, a metal nano-wire is embedded in polymer resin, so that a surface thereof is flattened. Thus, when the flexible transparent electrode is applied to an electronic material, a probability that short-circuiting occurs is low and the flexible transparent electrode may be applied to an OLED, a solar cell and the like.

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 method of forming a flexible transparent electrode in which a pattern is formed without introducing a lithographic apparatus by introducing a surface treatment process in the process of manufacturing a flexible transparent electrode, and is remarkably superior to a flexible transparent electrode manufacturing process in which patterning is performed through a lithography process We propose a method to fabricate flexible transparent electrodes with embedded metal nano wires patterned with low process water and process cost.

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 essential 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, since all of the above methods require expensive patterning equipment and complicated processes, it is impossible to completely eliminate the problems of photolithography, and a new patterning technology capable of securing cost competitiveness, in particular, a metal nanowire embedded flexible It is necessary to develop a new patterning technique suitable for a transparent electrode.

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.

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

It is an object of the present invention to provide a novel manufacturing method of a flexible transparent electrode patterned by a relatively simple method without requiring a wiring coating process and a sacrificial layer removal process using expensive equipment such as a photolithography process.

Specifically, the present invention aims to provide a novel method of forming a pattern by controlling the adhesive force between a metal nanowire and a polymer resin by applying plasma or ultraviolet-ozone treatment to the polymer resin.

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

The problem of surface roughness in the manufacture of flexible transparent electrode based on metal nanowires is that the metal nanowires are coated on a glass or silicon wafer substrate and then the flexible curable polymer resin is coated and impregnated with the metal nanowires in the curable polymer resin I could solve it.

However, due to the high adhesion strength between the metal nanowire and the glass substrate, there is a problem that only the polymer film is separated and the metal nanowires remain on the substrate even after the curable polymer resin is cured and removed.

In order to solve this problem, it is possible to solve this problem by introducing a release layer having excellent adhesion to the substrate and at the same time weakening the adhesion between the metal nanowire and the substrate.

However, the problem of separating the metal nanowires from the substrate by the introduction of the release layer has been solved, but the flexible transparent electrode manufactured by this method has a difficulty in applying to the electronic device because the pattern is not formed. The patterning of such a transparent electrode can be generally solved by a photolithography technique, but it has a disadvantage that the process is complicated and a cost is high.

The inventors of the present invention have studied a patterning technique capable of being applied to an electronic device and minimizing a process step and a cost. As a result, the adhesion between the substrate and the metal nanowire can be improved by hydrophilizing the release layer or the hydrophobic polymer film substrate In particular, it has been found that a minute pattern can be formed when a hydrophilic treatment is partially performed using a mask, thereby completing the present invention.

One aspect of the present invention is

a) a step of positioning a mask on a hydrophobic polymer substrate made of a substrate having a release layer made of a hydrophobic polymer resin or a hydrophobic polymer resin and performing a hydrophilization treatment to hydrophilize the portion without a mask;

b) removing the mask, applying a metal nanowire solution, and drying the metal nanowire solution 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 patterned metal nanowire layer;

/ RTI >

Wherein the release layer or the hydrophobic polymer substrate and the polymer film are incompatible with each other.

In one embodiment of the present invention, the solubility parameter? ₁ of the hydrophobic polymer resin and the solubility parameter? 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 ≤ Δδ

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

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

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-based resin, a polyacetal-based resin, and a polyacrylic 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 embodiment of the present invention, in the substrate on which the release layer is formed, the substrate may be any one selected from silicon, quartz, glass, silicon wafer, polymer, metal and metal oxide.

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 hydrophilization treatment in step a) 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, in the hydrophilization treatment, the treatment condition is A _{1 when} the adhesion between the metal nanowire and the curable polymer resin is A ₁ , and when the adhesion between the release layer or the hydrophobic polymer substrate and the metal nanowire is A ₂ , May be performed in a range that satisfies the following formula (3).

[Formula 3]

A ₁ < A ₂

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 nm, and an aspect ratio of 500 to 800.

In one embodiment of the present invention, the metal nanowire solution may be one wherein 0.2 to 0.5% by weight of the metal nanowire is dispersed in one or two or more solvents selected from purified water, ethanol, methanol, 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.

In one embodiment of the present invention, in the step d), the polymer film in which the metal nanowires are embedded may be separated from the release layer by applying physical force during separation.

In another aspect of the present invention, there is provided a method of fabricating a polymer film, comprising the steps of: fabricating a polymer film and a metal nanowire layer sequentially, wherein the metal nanowire layer is patterned according to the shape of a mask, And the transparent electrode is a flexible transparent electrode in which a pattern is formed.

In one embodiment of the present invention, the transparent electrode may have a surface roughness of 0.5 to 2.5 nm.

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 lighting, an e-paper, an e-book, a touch panel or a display substrate.

The present invention can provide a new manufacturing method capable of forming a pattern by a method of adjusting the adhesive force between materials through plasma, ultraviolet-ozone, electron beam, or ion beam treatment.

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.

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 it can be applied to various electronic devices such as OLED and solar cell Do.

1 is a SEM photograph of a transparent electrode manufactured according to Example 1. Fig.
2 is an OM picture of a transparent electrode prepared according to Example 2. Fig.
3 is a photograph showing an embodiment of the metal mask used in Example 3. Fig.
4 is an OM picture of a transparent electrode manufactured according to Example 3. Fig.
5 is an OM picture of a transparent electrode manufactured according to Example 5. Fig.
6 is an OM picture of a transparent electrode manufactured according to Example 6. Fig.

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.

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

[Formula 2]

2 ≤ Δδ

In the above formula (2) units are 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 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, plasma, ultraviolet-ozone treatment, electron beam or ion beam treatment. That is, by treating a substrate or a hydrophobic polymer substrate having a release layer made of a hydrophobic polymer resin having weak adhesion with metal nanowires, that is, a releasable hydrophobic polymer substrate, with plasma, ultraviolet-ozone, electron beam or ion beam treatment, The adhesion between the metal nanowire and the release layer or the polymer substrate can be improved and the metal nanowire can be fixed to the substrate. At this time, the pattern can be formed by partially hydrophilizing by hydrophilizing treatment using a mask. When the metal nanowires are applied and the curable polymer resin is applied after the hydrophilization treatment, the metal nanowires not subjected to the hydrophilization treatment are weakly adhered to the release layer or the hydrophobic polymer substrate and are embedded in the curable polymer resin, By separating the polymer film in which the nanowires are embedded, a pattern is formed, and a flexible transparent electrode having a smooth surface can be produced.

More specifically, one aspect of the present invention is

a) a step of positioning a mask on a hydrophobic polymer substrate made of a substrate having a release layer made of a hydrophobic polymer resin or a hydrophobic polymer resin and performing a hydrophilization treatment to hydrophilize the portion without a mask;

b) removing the mask, applying a metal nanowire solution, and drying the metal nanowire solution 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 patterned metal nanowire layer;

/ RTI &gt;

Wherein the release layer or the hydrophobic polymer substrate and the polymer film are incompatible with each other.

Specifically, each step will be described. In the step a), the adhesive force is adjusted to form a pattern of the metal nanowires. The release layer is used to weaken adhesion between the substrate and the metal nanowires 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.

In addition, the hydrophobic polymer substrate may be a substrate made of a hydrophobic polymer resin without needing to form a separate release layer. Specifically, for example, an acrylic resin, a polyester resin, and more specifically, a polyethylene terephthalate resin , But is not limited thereto.

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

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 or the surface of the hydrophobic polymer substrate may have a contact angle with respect to water specifically 65 ° or more, more specifically 65 to 85 °. The surface of the release layer or the surface of the hydrophobic polymer substrate after plasma, ultraviolet-ozone, electron beam or ion beam treatment can be adjusted in hydrophilicity depending on the degree of plasma treatment. Specifically, for example, the contact angle with water is 50 ° or less, Lt; RTI ID = 0.0 &gt; 50 ~. &Lt; / RTI &gt;

In one embodiment of the present invention, the release layer or the hydrophobic polymer substrate formed of the hydrophobic polymer resin is preferably compatible with the polymer film formed of the curable polymer resin. In the present invention, the solubility parameter of the polymer parameter.

Specifically, the solubility parameter δ ₁ of the hydrophobic polymer resin and the solubility parameter 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 ≤ Δδ

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 polyacrylic 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, in the substrate on which the release layer is formed, silicon, quartz, glass, silicon wafer, polymer, metal, and metal oxide may be used as the substrate. 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.

As a method of forming the release layer on the substrate, spin coating, bar coating, roll-to-roll coating, or the like may be used, but the present invention is not limited thereto and can be modified using known techniques.

In addition, the thickness of the release layer formed on the substrate is not limited as long as it is capable of releasing the polymer nanowire-embedded polymer film from the substrate by physical force, while releasing the separation between the metal nanowire and the substrate Do 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, it may be formed by spin-coating polymethylmethacrylate on a glass or silicon wafer substrate, but is not limited thereto. Polymethylmethacrylate was applied to the entire surface of the substrate using a micropipette during spin coating, spin-coated at 2000 to 3000 rpm for 30 to 40 seconds, and heat-treated at 170 to 190 ° C for 30 seconds to 1 minute to form a release layer . &Lt; / RTI &gt; It is to be understood that this is for illustrative purposes only, and is not intended to be limiting.

Next, a mask is placed on a substrate or a hydrophobic polymer substrate on which a release layer made of a hydrophobic polymer resin is formed, and subjected to plasma, ultraviolet-ozone, electron beam, or ion beam treatment to hydrophilize the maskless portion.

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 the hydrophobic polymer substrate, or may be spaced apart from the release layer or the hydrophobic polymer substrate.

The adhesion of the release layer or the hydrophobic polymer substrate to the hydrophilic polymer substrate can be further improved by positioning the mask on the release layer or the hydrophobic polymer substrate and then performing plasma or ultraviolet-ozone, electron beam, or ion beam treatment. 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 adhesion of the release layer or the hydrophobic polymer substrate can be controlled by adjusting the pressure, power, and time during the plasma treatment or ultraviolet-ozone, electron beam, and ion beam treatment. More specifically, it is preferable to carry out in a range so as to satisfy the following equation 3 adhesion (A ₁₎ and a release layer or a predetermined adhesive force between the transport polymer substrate and a metal nanowire (A ₂₎ between the metal nanowires and the curable polymeric resin .

[Formula 3]

A ₁ < A ₂

When the curable polymer resin of step c) is applied in the range satisfying the formula 3, the metal nanowires not subjected to plasma treatment or ultraviolet-ozone, electron beam, or ion beam treatment have a strong adhesive force to the curable polymer resin The curable polymer resin impregnates and buries the metal nanowires to form a smooth surface in which the metal nanowires do not protrude on the surface. In this case, the hydrophobic resin or the hydrophobic polymer substrate used for the release layer and the non- So that a polymer film is formed while forming a smoother surface, and at the same time, it can be easily released from a release layer or a hydrophobic polymer substrate. In addition, the portion without the mask is hydrophilized by plasma treatment or ultraviolet-ozone, electron beam, or ion beam treatment, and the metal nanowires are fixed on the surface of the release layer or the hydrophobic polymer substrate. Therefore, when the polymer film is peeled off, And remains on the hydrophobic polymer substrate.

That is, the release layer or the hydrophobic polymer substrate has a weak adhesive force between the release layer or the hydrophobic polymer substrate and the metal nanowire at the portion where the mask is placed, The adhesion between the release layer or the hydrophobic polymer substrate and the metal nanowire is improved, and the metal nanowire is fixed to the release layer or the hydrophobic polymer substrate. In addition, when separating the polymer film in which the metal nanowires are embedded in the step d), the metal nanowires strongly fixed on the release layer or the hydrophobic polymer substrate are not separated and remain on the release layer or the hydrophobic polymer substrate to form a pattern can do.

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 , H ₂ , N ₂ , and Ar, and may be one in which a release layer or a hydrophobic polymer substrate is hydrophilized Any that is available 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. By enhancing the adhesion strength with the metal nanowires in the above range, it is possible to have a stronger adhesion force 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.

The 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.

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 one embodiment of the present invention, the metal nanowire solution is prepared by adding 0.1 to 1.0% by weight, more preferably 0.2% by weight, of the metal nanowire to any one or two or more solvents selected from purified water, ethanol, isopropyl alcohol, methanol and butyl carbitol. To 0.5% by weight dispersed in water.

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, as the density of the metal nanowires decreases, the transmittance increases, but the electrical conductivity decreases. Therefore, it is preferable to select the density, length and diameter of the metal nanowires considering the permeability 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 nm, and an aspect ratio of 500 to 800, but are 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 is not limited, but may be 25 to 90 nm, more preferably 70 to 40 nm.

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), a polymer film is prepared using a curable polymer resin having excellent compatibility with metal nanowires to impregnate the metal nanowires so as to lower the surface roughness of the metal nanowires. Thus, So that the wire can be impregnated to form a smooth surface. At this time, the metal nanowire in the part where the mask is located in step (a) is more adhesive and compatible with the curable polymer resin than the adhesive force between the metal nanowire and the release layer or the hydrophobic polymer substrate, The nanowires are embedded, and the metal nanowires in the hydrophilicized portion without the mask are firmly fixed to the release layer or the hydrophobic polymer substrate, so that they can not be embedded in the curable polymer resin.

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 or a resin having an incompatibility with a hydrophobic polymer substrate used for the release layer. More specifically, Is not limited as long as it satisfies the following equations (1) and (2).

[Formula 1]

Δδ = | δ ₂ - δ ₁ |

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

[Formula 2]

2 ≤ Δδ

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.

Further, from the viewpoint of heat treatment stability that can be introduced in the production of an electronic device, the glass transition temperature is more preferably 100 to 150 ° C or higher, but is not limited thereto.

In addition, in view of the application of the flexible device, the elastic modulus of the curable polymer is preferably 1 to 2,000 MPa, but 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 that are not fixed on a release layer or a hydrophobic polymer substrate. In the liquid phase, Or 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 or the hydrophobic polymer substrate and does not impair the physical properties of the metal nanowire. From the viewpoint of forming a polymer film having excellent transmittance, the ultraviolet curable polymer . &Lt; / RTI &gt; The ultraviolet curable polymer is not limited as long as it is a resin which is cured to complete solid when it is exposed to ultraviolet light of 280 to 350 nm, and it is more preferably a transparent colorless liquid. In this respect, Norland Optical Adhesive series from Norland Products can be used as a commercialized example. Specific examples thereof include NOA60, NOA61, NOA63, NOA65, NOA68, NOA68T, NOA71, NOA72, NOA73, NOA74, NOA75, NOA76, 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. The metal nanowires are embedded in the surface in the above-mentioned range, and a polymer film having a smooth surface can be formed.

Next, in step d), a flexible transparent electrode having a patterned metal nanowire layer is prepared by separating the polymer film embedded with the metal nanowires from the release layer. The plasma, ultraviolet-ozone, Electron beam, or ion beam treatment.

At this time, as described above, adhesion strength between the release layer and the metal nanowires is greatly improved at portions where the mask is not placed by plasma, ultraviolet-ozone, electron beam, or ion beam treatment, and the metal nanowires have already been formed on the release layer or the hydrophobic polymer substrate The metal nanowires excluding the metal nanowires fixed on the release layer or the hydrophobic polymer substrate are separated in a state of being buried when the polymer film is separated, 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 another aspect of the present invention, there is provided a method of fabricating a polymer film, comprising the steps of: fabricating a polymer film and a metal nanowire layer sequentially, wherein the metal nanowire layer is patterned according to the shape of a mask, And the transparent electrode is a flexible transparent electrode in which a pattern is formed.

In one embodiment of the present invention, the transparent electrode may be formed with a pattern having a surface roughness of 0.5 to 2.5 nm, but is not limited thereto.

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 material 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

Solubility parameters 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

The contact angle with distilled water was measured at constant temperature and humidity condition (20 ° C, 65% RH) using a contact angle meter of KRUSS DSA 100 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.

5) Transmittance (%)

The transmittance of the fabricated flexible transparent electrode was measured according to ASTM D1003 and expressed as a percentage. The haze and light transmittance were measured in the visible light region using a UV-Visible (SHIMADZU, UV-2600).

6) 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.

7) 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 and washed with an ultrasonic grinder for 10 minutes to remove foreign substances. Then, the glass substrate was immersed in isopropyl alcohol and washed with an ultrasonic grinder 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 의 of polymethyl methacrylate (Micro CHEM, 495 PMMA A2, weight average molecular weight of 495000 g / mol) was coated on the dried glass substrate using a micropipette, and then spin-coated at 3000 rpm for 30 seconds. Thereafter, the resultant was dried at 180 DEG C for 1 minute to form a release layer. The contact angle of the release layer was 70.0 °.

A polydimethylsiloxane (PDMS) block was well adhered to the substrate with the release layer formed thereon as a mask, and subjected to a hydrophilization treatment by plasma 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 using a micropipette. The spin speed of the spin coater was adjusted to 600 rpm by spin coating for 1 minute, followed by drying at 100 캜 for 1 minute to evaporate the solvent The adhesion between the 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 ultraviolet rays of 5.0 J / s · m ² for 15 minutes.

The completely cured polymer film was separated from the substrate, and silver nanowires having weakened adhesion to the substrate by the release layer were embedded in the curable polymer resin to form a flexible transparent electrode having a pattern, as shown in FIG.

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

[Example 2]

The same procedure as in Example 1 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 as shown in FIG. 2 to produce a flexible transparent electrode having a pattern.

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

[Example 3]

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 pattern was formed and is shown in FIG.

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 1, except that the coating density and the thickness of the silver nanowire solution were different.

That is, after rapidly applying 500 ㎕ of silver nanowire solution, the spin speed of the spin coater was adjusted to 1,200 rpm and spin-coated for 1 minute and dried at 100 캜 for 1 minute to evaporate the solvent and increase the adhesion between the silver nanowires A network was formed to form a silver nanowire coating layer.

As a result, it was confirmed that silver nanowires having different densities and thicknesses were embedded in the curable polymer resin to produce a flexible transparent electrode having a pattern.

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

[Example 5]

Example 2 was the same as Example 2 except that the treatment was carried out for 10 minutes under ultraviolet irradiation. As a result, as shown in FIG. 5, it was confirmed that the silver nanowire was embedded in the curable polymer resin to produce a flexible transparent electrode having a pattern.

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

[Example 6]

Example 2 was the same as Example 2 except that ultraviolet irradiation was performed for 60 minutes. As a result, as shown in FIG. 6, it was confirmed that the silver nanowire was embedded in the curable polymer resin to produce a flexible transparent electrode having a pattern.

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

[Example 7]

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 pattern.

[Example 8]

In Example 1, the release layer was made of polymethyl methacrylate having a solubility parameter of 19, and the curable polymer resin was a UV curable epoxy resin having a solubility parameter of 17, . 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 pattern.

[Example 9]

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 pattern.

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

[Example 10]

In Example 1, polymethyl methacrylate having a solubility parameter of 19 was used as the release layer, and a UV curable epoxy resin having a solubility parameter of 25 was used as the curable polymer resin. In the same manner as in Example 1, . 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 pattern.

Release layer contact angle
(°) Contact angle (°) after hydrophilization treatment Surface roughness Transmittance Sheet resistance Film thickness Example 1 70 40 1.04 nm 83.9% 15.5Ω / □ 200μm Example 2 70 35 0.77 nm 84.7% 14.8Ω / □ 200μm Example 3 70 35 0.77 nm 84.7% 14.8Ω / □ 200μm Example 4 70 40 0.77 nm 88.2% 26.12Ω / □ 200μm Example 5 70 50 1.02 nm 83.2% 12.6Ω / □ 200μm Example 6 70 20 0.75 nm 84.2% 13.8Ω / □ 200μm

Claims (17)

a) providing a mask on a hydrophobic polymer substrate made of a hydrophobic polymer resin or a hydrophobic polymer resin formed on a substrate, and performing a hydrophilization treatment to hydrophilize the maskless portion;
b) removing the mask and applying the metal nanowire solution to the release layer or the entire surface of the hydrophobic polymer substrate, followed by drying to form a metal nanowire coating layer;
c) applying a curable polymer resin to the metal nanowire coating layer and curing the polymer nanofibers to prepare a polymer film having embedded portions of the metal nanowires that have not been hydrophilized; 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 patterned metal nanowire layer;
/ RTI &gt;
Wherein the release layer or the hydrophobic polymer substrate and the polymer film are nonconductive.
The method according to claim 1,
The solubility parameter δ ₁ of the hydrophobic polymer resin and the solubility parameter δ ₂ of the curable polymer resin Wherein a difference is Δδ of the following formula (1) satisfies the following formula (2).
[Formula 1]
Δδ = | δ ₂ - δ ₁ |
[Formula 2]
2 ≤ Δδ
In the above formula (2) units are J ^{1/2 /} cm ^2/3.
The method according to claim 1,
Wherein a hydrophilic polymer substrate surface has a contact angle with respect to water of 65 deg. Or more before the hydrophilization treatment and a hydrophilic polymer substrate surface has a contact angle with water of 50 deg. Or less after the hydrophilization treatment.
The method according to claim 1,
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 polyacrylic resin. 2. The method of manufacturing a flexible transparent electrode according to claim 1,
The method according to claim 1,
Wherein the curable polymer resin is selected from an ultraviolet curing type polymer resin, a thermosetting type polymer resin, a room temperature moisture curing type polymer resin, and an infrared curing type polymer resin.
The method according to claim 1,
Wherein in the substrate on which the release layer is formed, the substrate is any one selected from silicon, quartz, glass, silicon wafer, polymer, metal, and metal oxide.
The method according to claim 1,
Wherein the mask is made of a siloxane-based polymer, a silicone rubber, or a metal material.
The method according to claim 1,
Wherein the hydrophilization treatment is plasma, ultraviolet-ozone, electron beam or ion beam treatment in the step (a).
9. The method of claim 8,
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.
9. The method of claim 8,
In the hydrophilization treatment, the processing conditions are set such that the adhesive force between the metal nanowire and the curable polymer resin is A ₁ , and the adhesion force between the release layer or the hydrophobic polymer substrate and the metal nanowire is A ₂ . Wherein the transparent electrode layer is formed on the surface of the flexible transparent electrode.
[Formula 3]
A ₁ < A ₂
The method according to claim 1,
Wherein the metal nanowire is selected from silver (Ag), copper (Cu), aluminum (Al), gold (Au), platinum (Pt), nickel (Ni), titanium A length of 10 to 50 nm, and an aspect ratio of 500 to 800. The method of manufacturing a flexible transparent electrode according to claim 1,
The method according to claim 1,
Wherein the metal nanowire solution is prepared by dispersing 0.2 to 0.5 weight% of the metal nanowires in one or two or more solvents selected from purified water, ethanol, methanol, isopropyl alcohol, and butyl carbitol. Way.
The method according to claim 1,
Wherein the application is selected from spin coating, bar coating, and roll to roll coating.
The method according to claim 1,
Wherein in step (d), the polymer film embedded with the metal nanowires is separated from the release layer by applying a physical force when the polymer film is separated.
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