KR101696300B1 - Electrode and manufacturing method thereof - Google Patents

Abstract

A highly reliable electrode and a method of manufacturing the same are provided. In the electrode manufacturing method according to the present invention, nanowire is coated on a substrate to form a nanowire layer. When the nanowire layer includes a pattern region and a removal region, adhesion between the nanowire layer and the substrate in the pattern region Is adjusted to be greater than the adhesion force between the nanowire layer and the substrate in the removal region, and then the removal region is removed to prepare the electrode.

Description

ELECTRODE AND MANUFACTURING METHOD THEREOF

The present invention relates to an electrode and a manufacturing method thereof, and more particularly, to a reliable electrode and a manufacturing method thereof.

Indium tin oxide (ITO) has generally been used as the transparent electrode. However, indium tin oxide has been pointed out as a factor that hinders the price competitiveness of the final product because it is a typical rare material. Therefore, it is of great interest to use ITO or replace it with other materials.

As an attempt to replace the ITO electrode, the nanowire technology based on silver (Ag) has been widely used in the fields of solar cells such as touch panels and OPVs, wiring electrodes of various electronic circuits and OLED manufacturing fields . In the case of metal nanowires, due to the unique high conductivity and the shape of a large aspect ratio, they are attracting particular attention because they can be compatible with high transparency and high conductivity when used as a transparent electrode. Further, even when the transparent electrode is not used, it has been evaluated that it is highly likely to be utilized in the development of a next-generation flexible display or electronic parts due to its excellent flexibility.

When a metal nanowire is coated on a flexible substrate such as a plastic substrate for use in a flexible electronic device, the adhesion of the nanowire to the substrate is low, so that the nanowire peels off or breaks upon bending or physical stress . Further, the surface roughness becomes rough due to the pores existing between the nanowire and the substrate. If the material in the subsequent process penetrates into the voids on the nanowire and the substrate, problems such as shorts may also occur.

In addition, when a photoresist, which is a commonly used method for patterning nanowires, is coated, and etching and photoresist removal processes are used after exposure and development, there arises a problem that the nanowires are peeled off the substrate through various steps easy. Therefore, it is pointed out that patterning of nanowires is very difficult in a general photolithography process.

In order to solve this problem, a process of patterning after increasing the bonding force by adding a binder to the metal nanowire dispersion and a process of partially losing the conductivity of the nanowire by photo-oxidation method and then patterning have been developed.

Since the method of adding a binder is limited to the characteristics and color of the binder for use in a transparent electrode, it is difficult to select the material, and various processes are added, thus limiting the process time and the process step. In the photo-oxidation method, nanowire patterning is possible, but since the steps of using the photoresist are not performed, and the problem of adhesion between the nanowire and the substrate still remains, development of technologies for such problems is continuously being requested.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a highly reliable electrode and a method of manufacturing the same.

According to an aspect of the present invention, there is provided an electrode manufacturing method including: forming a nanowire layer on a substrate by applying nanowire on the substrate to form a nanowire layer; Wherein the nanowire layer comprises a pattern region and a removal region, the adhesion force adjusting step such that the adhesion force between the nanowire layer and the substrate in the pattern region is greater than the adhesion force between the nanowire layer and the substrate in the removal region; And a removal step of removing the removal area.

The method further comprises an adhesive layer forming step of forming an adhesive layer on the substrate before the nanowire layer forming step and the adhesive strength adjusting step is performed so that the pattern area adhesion force of the adhesive layer in the pattern area is larger than the removal area adhesion force of the adhesive layer in the removal area .

The adhesion adjustment step may be performed by photo-sintering the pattern region and photo-sintering the nanowire in the pattern region.

Alternatively, the adhesion adjusting step may be performed so as to photo-sinter the nanowire layer, wherein the light sintering light amount in the pattern area is larger than the light sintering light amount in the removal area.

The removing step may be a step of separating the removal region from the substrate using an adhesive object.

Alternatively, the removing step may be performed by immersing the substrate in which the adhesion-controlled nanowire layer is formed in the solution and applying a physical impact.

At this time, it is preferable that the nanowires in the removed region have an average aspect ratio of 50% to 100% of the average aspect ratio of the nanowires before the adhesion adjustment step is performed.

According to another aspect of the present invention there is provided an electrode comprising a substrate and a patterned nanowire layer on the substrate, wherein the nanowire layer and the nail are optically sintered from the interface of the substrate.

As described above, according to the embodiments of the present invention, the electrodes are formed by using nanowires. By forming patterns by differentiating the adhesive force between the pattern portion and the portion to be removed at the time of electrode formation, It is possible to form a pattern at a low cost, thereby reducing the cost.

In addition, since the formed nanowire layer has high adhesion to the substrate, the nanowire is less likely to be separated during the subsequent process, thereby improving the reliability of the final product.

In addition, as the adhesion between the nanowire and the substrate is increased, the gap between the nanowire and the substrate can be minimized, and the flexibility and surface roughness can be minimized. Thus, high quality products can be produced, There is an effect available.

Finally, in the case of nanowires removed from the removal region, since the nanowires are removed without changing the characteristics of the nanowires as in the photo-oxidation method, the separated nanowires can be easily reused, resulting in a large cost reduction effect.

FIGS. 1 to 4 are views for explaining a method of manufacturing an electrode according to an embodiment of the present invention.
Figs. 5 and 6 are SEM images of the nanowire layer on the substrate, respectively, Fig. 5 is an image before light sintering, and Fig. 6 is an image after light sintering.
FIG. 7 is a view showing an electrode in which a silver nanowire layer is formed on a PET film, only a part of the IPL is irradiated, and then an ultrasonic wave is irradiated to remove the region where the IPL is not irradiated.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. The embodiments of the present invention are provided to enable those skilled in the art to more fully understand the present invention. It should be understood that while the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, The present invention is not limited thereto.

FIGS. 1 to 4 are views for explaining a method of manufacturing an electrode according to an embodiment of the present invention. Hereinafter, an electrode according to the present invention and a method of manufacturing the same will be described with reference to FIGS. 1 to 4 and FIG. 5 showing a nanowire on a substrate of a non-irradiated region.

The electrode manufacturing method according to the present embodiment includes: a nanowire layer forming step of forming a nanowire layer by applying nanowire on a substrate; Wherein the nanowire layer comprises a pattern region and a removal region, the adhesion force adjusting step such that the adhesion force between the nanowire layer and the substrate in the pattern region is greater than the adhesion force between the nanowire layer and the substrate in the removal region; And a removal step of removing the removal area.

1, a nanowire layer forming step of forming a nanowire layer 120 by applying nanowires on a substrate 110 is performed. The substrate 110 may be a flexible substrate such as a glass substrate or a silicon substrate and may be a flexible plastic substrate such as a polyethylene terephthalate A polyether sulfone (PES) substrate can be used. In addition, when the electrode is used for a display, the substrate should be a transparent electrode since it is a transparent electrode.

The nanowire layer 120 includes a pattern region 121 and a removal region 122. The pattern region 121 is an area where the patterned nanowire layer 123 remains after the patterning process for the electrode pattern. The removal region 122 is the area to be patterned and separated to form the patterned nanowire layer 123. The pattern shape of Fig. 1 is illustrative and can be formed differently depending on the use of the electrode.

The nanowire layer may comprise metal nanowires in the form of nanometers of wire. For example, the metal nanowires may be silver (Ag), gold (Au), copper (Cu), nickel (Ni), platinum (Pt), palladium (Pd), or aluminum (Al) And a core-shell wire made of a combination of the two.

The portion required to function as an electrode in the nanowire layer 120 is the pattern region 121. [ Therefore, it is necessary to pattern the nanowire layer 120 more effectively, leaving only the pattern region 121, and removing the removed region 122.

The nanowire layer 120 is a form in which metallic nanowires are two-dimensionally coated on the upper surface of the substrate 110. Referring to FIG. 5, a nanowire is coated on a substrate 410 to form a nanowire layer 420. Since the metal nanowires can form a percolated network with only a small distribution density, even if there is a vacant area as shown in FIG. 5, high electrical conductivity can be exhibited, Electrode formation is possible.

In order to form the patterned nanowire layer 123 by removing the removal region 122 from the nanowire layer 120 to leave only the pattern region 121, the pattern region 121 and the removal region 122 The adhesion between the nanowire layer 120 and the substrate 110 is controlled. For the sake of convenience, the adhesion force between the nanowire layer 120 and the substrate 110 is referred to as an interfacial adhesion force. That is, the interfacial adhesion force in the pattern area 121 is adjusted to a level higher than the interfacial adhesion force in the removal area 122. Preferably, the pattern region 121 has an adhesive force and the removal region 122 has no adhesive force.

In this case, it is possible to pattern the nanowire layer 120 by controlling the method of removing the removed region to leave the pattern region 121. It is possible to perform patterning by adjusting only the adhesive force without requiring a complicated process such as photolithography.

Methods for adjusting the relative interfacial adhesion force in the pattern region 121 and the removal region 122 are shown in Figs. 3 and 4. Fig.

Referring to FIG. 3, an adhesive layer 230 may be formed on the substrate 210 before forming the nanowire layer. The shape of the adhesive layer 230 is the same as the shape of the pattern area. That is, the adhesive layer 230 is formed to correspond to the pattern region, and is not formed in the removed region. Accordingly, in the nanowire layer formed with the adhesive layer 230, the interfacial adhesion between the pattern region and the substrate is increased, and the interfacial adhesion with the substrate is very low in the removed region. Therefore, according to the removal method of the removal region to be described later, the nanowires of the removal region are easily removed, and only the pattern region remains, thereby allowing the patterning of the wire layer. That is, patterning can be performed by adjusting the interfacial adhesion between the pattern region and the removed region.

Alternatively, the interfacial adhesion between the pattern region and the removal region can be controlled. For example, as shown in FIG. 4, a mask 340 may be formed on the nanowire layer 320 to irradiate light, for example, intensified pulsed light (IPL). The mask 340 is formed so as to coincide with the shape of the removed region so that the IPL is irradiated only to the pattern region. Thus, the nanowire is photo-sintered in the pattern area irradiated with IPL. Alternatively, light irradiation may be performed not only on a part of the nanowire layer 220 but also on both the pattern region and the removal region. In this case, the amount of light irradiated to the pattern region is larger than the amount of light irradiated to the removal region The light sintering level of the nanowire in the pattern region can be increased. That is, the adhesive force between the pattern area and the removal area can be adjusted as desired by adjusting the amount of light to be irradiated. The adhesion adjustment step may be performed using both the adhesive layer and the light sintering step.

When the interfacial adhesion of the patterned and removed regions of the nanowire layer is adjusted, the removed regions are removed and the nanowire layer 120 is patterned.

Removal of the removal region can be performed, for example, by applying an adhesive material such as a roller coated with an adhesive on top of the nanowire layer with controlled adhesion. At this time, the adhesive force of the adhesive object for removal of the removal area is larger than the interfacial adhesion force of the removal area, and must be adjusted to be smaller than the interfacial adhesion force of the pattern area.

Alternatively, when the adhesion control is performed according to a light sintering process through light irradiation, the removing step may be performed by immersing the substrate on which the nanowire layer with the controlled adhesion strength is formed in a solution and applying a physical impact. When the substrate is immersed in a solution and a physical impact is applied, the nanowires in the removal region with low adhesion are released into the solution. The physical impact can be performed, for example, by irradiating ultrasonic waves. When a physical impact such as ultrasonic irradiation is applied, the nanowire layer in the removal region having a low adhesive force is separated, and an electrode including the nanowire layer having only the pattern region can be obtained.

An electrode 100 comprising a patterned nanowire layer 123 is shown in FIG. In this case, the electrode 100 is an electrode including a substrate 110 and a patterned nanowire layer 123 on the substrate 110. Due to the adjustment of the adhesive force of the nanowire layer, the photo- So that the nanowire is optically sintered at the interface between the nanowire layer and the substrate.

In this case, if the photo-sintering process is not performed in the removal region and the photo-sintering process is performed only in the pattern region, the nanowires separated in the removal solution may exhibit the original characteristics. In other words, it is preferable that the nanowires in the removed region remove at least one or more of the characteristics of the nanowires included in the original nanowire layer in terms of conductivity and the like, because the nanowires can be reused again, Cost effective.

If the nanowire in the removal region is obtained in the form of nanoparticles, it is difficult to reuse because it does not show the physical properties of the nanowire anymore. Thus, the nanowires in the removal region should be in nanowire form to retain the electrical and physical properties of the nanowire before the adhesion control step is performed. In this case, since the physical properties of the nanowire can be expressed by the aspect ratio of the diameter to the length, if the nanowire has an aspect ratio of 50% to 100% of the initial nanowire, the nanowire exhibits properties similar to those of the initial nanowire, have. Preferably, the average aspect ratio of the nanowires in the removed region is 80% of the average aspect ratio of the initial nanowires, and most preferably 100% of the average aspect ratio of the initial nanowires.

In addition, if the solution used for ultrasonic irradiation for physical impact is the same as the solvent of the nanowire dispersion liquid when the nanowire layer is applied to the substrate, the nanowire can be directly reused in the electrode manufacturing process without the necessity of separate extraction, There is an advantage that a highly efficient and complicated purification process or reduction process need not be performed.

Figs. 5 and 6 are SEM images of the nanowire layer on the substrate, respectively, Fig. 5 is an image before light sintering, and Fig. 6 is an image after light sintering. FIG. 5 is an SEM image after silver nano wire on a PET substrate is applied, and FIG. 6 is an SEM image of a pattern portion after photo-sintering the same. 5 and 6 show minute differences in the air gap between the substrate and the nanowire layer, respectively. 5, the nanowire 420 on the substrate 410 has an air gap formed therebetween. Particularly, if the nanowire 420 is located more than two layers, a gap exists between the upper nanowire 420 and the substrate 410.

In contrast, in FIG. 6, the gap between the nanowire 520 and the substrate 510 is relatively reduced. The nanotube 520 may be optically sintered so that the photo-sintered portion may be pushed into the gap with the substrate 510 and the temperature of the substrate 510 may be increased by the heat generated during the photo- It may have been located closer. In any case, as shown in FIG. 5, it can be seen from the image that the interface adhesion is higher than when the nanowire 420 is adsorbed to the substrate 410 only physically.

FIG. 7 is a view showing an electrode in which a silver nanowire layer is formed on a PET film, only a part of the IPL is irradiated, and then an ultrasonic wave is irradiated to remove the region where the IPL is not irradiated. The method of controlling the adhesion between the pattern region and the removal region by photo-sintering the nanowire using the IPL is a method of effectively patterning the nanowire layer by a very simple method, It is possible to manufacture a high-quality electrode and an electronic device using the same, in particular, a flexible electronic device.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the invention as defined by the appended claims. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

100 electrodes
110, 210, 310, 410, 510 substrate
120, 220, 320, 420, 520 nanowire layers
121 Pattern area
122 removal area
123 patterned nanowire layer
230 adhesive layer
340 Mask

Claims (8)

delete delete A nanowire layer forming step of applying a nanowire on a substrate to form a nanowire layer; Wherein the nanowire layer comprises a pattern region and a removal region such that the adhesion force between the nanowire layer and the substrate in the pattern region is greater than the adhesion force between the nanowire layer and the substrate in the removal region An adhesive force adjusting step; And a removal step of removing the removal region,
Wherein the adhesive strength adjusting step comprises:
And photo-sintering the pattern region to photo-sinter the nanowire in the pattern region to increase the adhesion between the nanowire layer and the substrate.
A nanowire layer forming step of applying a nanowire on a substrate to form a nanowire layer; Wherein the nanowire layer comprises a pattern region and a removal region such that the adhesion force between the nanowire layer and the substrate in the pattern region is greater than the adhesion force between the nanowire layer and the substrate in the removal region An adhesive force adjusting step; And a removal step of removing the removal region,
Wherein the adhesive strength adjusting step comprises:
The nanowire layer is photo-sintered,
Wherein the amount of photo-sintering light in the pattern region is greater than the amount of photo-sintering light in the removed region, thereby increasing the adhesion between the nanowire layer and the substrate in the pattern region.
The method according to claim 3 or 4,
Wherein,
And separating the removal region from the substrate using an adhesive object.
The method according to claim 3 or 4,
Wherein,
Wherein the nanowire layer is formed by immersing the substrate on which the adhesion-controlled nanowire layer is formed in a solution, and applying a physical impact.
The method according to claim 3 or 4,
Wherein the nanowires in the removed removal region have an average aspect ratio that is 50% to 100% of the average aspect ratio of the nanowires before the adhesion adjustment step is performed.
delete

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