KR20120086209A - Method for forming uniform conducting polymer electrode and the electrode material - Google Patents

Abstract

PURPOSE: A method for forming a uniform conductive polymer electrode and an electrode material are provided to have better electrical conductivity than a conventional conductivity polymer since electrodes including the conductivity polymer are formed. CONSTITUTION: A conductive polymer solution is prepared. A mixture solution is formed by mixing an addictive solvent and a surfactant with the conductive polymer solution(S601). The mixture solution is coated on a substrate(S602). The mixture solution is thermally treated(S603).

Description

Uniform conductive polymer electrode formation method and electrode material {METHOD FOR FORMING UNIFORM CONDUCTING POLYMER ELECTRODE AND THE ELECTRODE MATERIAL}

The present disclosure relates to a method of forming a uniform conductive polymer electrode and an electrode material.

Display devices, solar cells, touch panels and the like are provided with electrodes for the movement of charge or the supply of power.

In such touch panels, conductive polymers are used as alternative electrodes suitable for flexible devices. However, when the electrode including the conductive polymer is formed on a polyethylene terephthalate (poly (ethylene terephthalate), PET) substrate, it is difficult to uniform coating due to the opposite characteristics of the electrode and the substrate. This requires an additional process on the substrate, which leads to an increase in process cost.

Embodiments provide an electrode material having excellent electrical and physical stability and an electrode forming method using the same.

An electrode material according to an embodiment includes a conductive polymer, a dopant and a surfactant.

Electrode forming method according to an embodiment, preparing a conductive polymer solution; Mixing an additional solvent and a surfactant with the conductive polymer solution to form a mixed solution; Coating the mixed solution on a substrate; And heat treating the mixed solution.

In the electrode material according to the embodiment, since the electrode including the conductive polymer is formed, the electrical conductivity is very excellent compared to the existing touch panel. In addition, due to the nature of the conductive polymer can be applied to a large-area flexible device can greatly improve the physical properties. These electrodes have high transmittance and conductivity, and have low sheet resistance, thereby improving performance of the display to which the electrodes are applied.

On the other hand, in the electrode forming method according to the embodiment, the electrode can be formed without a high temperature process and a vacuum process, so the process is simple, and defects and manufacturing costs can be reduced. In addition, an additional process for uniform coating of the conductive polymer and the polyethylene terephthalate substrate can be omitted.

1 is a schematic plan view illustrating an embodiment of a touch panel.
FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1.
3 is a chemical formula for explaining the molecular structure of the electrode material according to the embodiment.
4 is a chemical formula for explaining the molecular structure of Triton X-100 included in the electrode material according to the embodiment.
5 is an enlarged view illustrating an enlarged view of portion A of FIG. 2.
6 is a schematic view for explaining the electrode forming method according to the embodiment.
7 is a photograph of an electrode surface formed by Example 1. FIG.
8 is a photograph of an electrode surface formed by Comparative Example 1. FIG.
9 is a photograph of an electrode surface formed by Example 2. FIG.
10 is a photograph of an electrode surface formed by Comparative Example 2. FIG.

In the description of embodiments, each layer, region, pattern, or structure may be “on” or “under” the substrate, each layer, region, pad, or pattern. Substrate formed in ”includes all formed directly or through another layer. Criteria for the top / bottom or bottom / bottom of each layer will be described with reference to the drawings.

The thickness or the size of each layer (film), region, pattern or structure in the drawings may be modified for clarity and convenience of explanation, and thus does not entirely reflect the actual size.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

An electrode material according to an embodiment will be described in detail with reference to FIGS. 1 to 5.

First, an example in which an electrode material according to an embodiment may be applied with reference to FIGS. 1 and 2 will be described in detail with reference to FIGS. 3 to 5.

1 is a schematic plan view illustrating an embodiment of a touch panel, and FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1. 3 is a chemical formula for explaining the molecular structure of the electrode material according to the embodiment, Figure 4 is a chemical formula for explaining the molecular structure of the Triton X-100 contained in the electrode material according to the embodiment, Figure 5 Is an enlarged view showing an enlarged view.

1 and 2, in the touch panel according to the embodiment, an effective area AA for detecting a position of an input device and a dummy area DA positioned outside the effective area AA are defined. .

Here, the electrode 30 may be formed in the effective area AA to detect the input device. In the dummy area DA, a wiring 40 connected to the electrode 30 and a printed circuit board (not shown, the same below) that connects the wiring 40 to an external circuit (not shown, the same below), etc. This can be located. An outer dummy layer 20 may be formed in the dummy area DA, and a logo 20a may be formed in the outer dummy layer 20. The touch panel will be described in more detail as follows.

The outer dummy layer 20 is formed on the substrate 10, and the electrode 30 and the wiring 40 are formed on the polyethylene terephthalate (PET) substrate 60. An optically clear adhesive (OCA) 50 may be formed to adhere the substrate 10 and the polyethylene terephthalate substrate 60. Although not shown, a printed circuit board may be connected to the wiring 50.

In the drawings and description, the touch panel is illustrated as a device to which the electrode material of the present invention can be applied, but the present invention is not limited thereto. Thus, the electrode material according to the present invention can also be used to form electrodes or wiring of display devices such as plasma display panels, liquid crystal display panels, electrodes or dashed lines of solar cells, and the like.

The thickness of the electrode 30 may be 10 nm to 1000 nm. If the thickness of the electrode 30 is less than 10 nm, the sheet resistance is too large to deteriorate the conductivity, and if the thickness of the electrode 30 is greater than 1000 nm, the resistance is lowered, but the transmittance is also lowered, thereby degrading the visibility of the display to which the electrode 30 is applied. .

3 to 5, an electrode material according to an embodiment includes a conductive polymer, a dopant and a surfactant 32.

The conductive polymer may include at least one of polyethylene (3,4-Ethylenedioxythiophene, PEDOT), polyaniline, polypyrrole, polythiophene, and derivatives thereof. That is, the conductive polymer is a π-conjugated polymer, and may include a material in which electrical conductivity is increased by the addition of a dopant. The π-conjugated polymer has a chain structure in which carbon atoms repeat a single bond and a double bond, and the π-electron can move freely.

The dopant may include at least one of polystyrene sulfonate (PSS), dodecylbenzene sulfonate, toluene sulfonyl, chemposulfonic acid, benzenesulfonic acid, hydrochloric acid, and derivatives thereof. That is, the dopant may include a material capable of increasing the electrical properties of the conductive polymer.

As such, when the electrode material includes the conductive polymer and the dopant, the electrode material may be variously applied to forming the electrode of the flexible device due to the flexible characteristics of the conductive polymer. In addition, compared to the conventional indium tin oxide (ITO) used inexpensive price and easy manufacturing process can improve the productivity when forming the electrode.

In one embodiment, a composite (PEDOT: PSS complex) 31 of polyethylenedioxythiophene (hereinafter referred to as "PEDOT") 31b and polystyrenesulfonic acid (hereinafter referred to as "PSS") 31a is formed. It can be used as an electrode material.

PEDOT 31b is a conjugated polymer based on polythiophene and serves to transfer positive charges. The sulfonyl group of PSS 31a is deprotonated to become negatively charged. Both positively and negatively charged materials are hydrophilic.

Specifically, the PSS 31a induces the PEDOT 31b to be effectively dispersed in the aqueous solution. In addition, by matching the charge balance between the PEDOT 31b and the PSS 31a, the PEDOT 31b performs ionic bonding to the PSS 31a polymer chain very strongly, whereby the PEDOT 31b and the PSS 31a are in an aqueous solution. ) Can be well dispersed without being separated from each other. PEDOT 31b serves to maintain electrical conductivity for electrode characteristics. At this time, the weight ratio of PEDOT 31b: PSS 31a may be 1: 0.01 to 1:20. If PSS has a weight ratio of less than 0.01 to 0.01, it is difficult to disperse the composite 31 of PEDOT: PSS, etc., and if the weight ratio is greater than 1:20 to 20, the weight ratio of PEDOT 31b is relatively high. May decrease, resulting in weak conductivity.

Referring to FIG. 3, n and m of the PSS 31a and PEDOT 31b units may be 1000 or more, respectively.

Although the drawings and the description include including both the PSS and the PEDOT, the embodiment is not limited thereto and may include only the PEDOT maintaining the electrical conductivity.

While the electrode material including the conductive polymer is hydrophilic, the polyethylene terephthalate substrate 60 on which the electrode 30 is formed exhibits hydrophobicity. Due to these opposing characteristics, the repulsive force between materials is shown, and as a result, coating is not uniform. Therefore, in order to form the electrode 30 including the conductive polymer, a pretreatment process of the polyethylene terephthalate substrate 60 is required. Specifically, the pretreatment process may be performed by coating the polyethylene terephthalate substrate 60 with a hydrophilic material or treating the polyethylene terephthalate substrate 60 with ultraviolet ozone. However, this additional process complicates the process and raises the cost of the process. In particular, these additional processes are not suitable for roll to roll continuous processes suitable for mass production. In the present embodiment, the electrode material may further include a surfactant 32 in addition to the conductive polymer 31 to enable uniform coating without an additional process.

Surfactant 32 may comprise a non-ionic surfactant. Nonionic surfactants may include a saturated alcohol, a polyoxyethylene glycol alkyl ester, a polyoxyethylene glycol octiphenol ester, and a polyoxyethylene glycol alkylphenol ester series as surfactants that are not polarized in the solvent.

In one example, the non-ionic surfactant may include Triton X-100. Triton X-100 is a nonionic surfactant, which is divided into a hydrophobic tetramethylbutyl-phenyl group 32a and a hydrophilic ethylene oxide 32b group. When the electrode material including the surfactant 32 and the PEDOT: PSS composite material 31 is coated on the polyethylene terephthalate substrate 60, it may have a structure as shown in FIG. 5. That is, tetramethylbutyl-phenyl group 32a, which is a hydrophobic group of the surfactant 32, is positioned on the surface of the hydrophobic polyethylene terephthalate substrate 60, and an ethylene oxide group 32b, which is a hydrophilic group, is positioned thereon. The hydrophilic PEDOT: PSS complex (31) helps to uniformly coat.

Hereinafter, a method of forming an electrode will be described in detail with reference to FIG. 6. For the sake of clarity and simplicity, the same or very similar parts to those described above will be omitted, and the different parts will be described in detail.

6 is a schematic view for explaining the electrode forming method according to the embodiment.

First, the step (S601) of mixing the solution will be described in detail. In this step, a mixed solution is formed, including the conductive polymer solution, the addition solvent, and the surfactant.

First, the conductive polymer solution includes a conductive polymer, a dopant and a solvent. The conductive polymer may be prepared in a dispersed state in a solvent. In one embodiment, the conductive polymer may comprise PEDOT and the dopant may comprise PSS. The solvent may be water, for example. However, as described above, PSS may not be included and only PEDOT may be included, which is also within the scope of the present embodiment. The conductive polymer and the dopant may include 0.1 wt% to 20 wt% of the conductive polymer solution. Therefore, if less than 0.1% by weight is included in the low electrical conductivity can not serve as an electrode, when contained in more than 20% by weight, it does not dissolve well in the solvent but aggregates in the solvent may be a problem during coating have.

In addition, the addition solvent includes dimethyl sulfoxide (DMSO) or en-methylpyrrolidone (N-Methyl-pyrrolidone, NMP), it is preferable to add dimethyl sulfoxide. However, the embodiment is not limited thereto, and various organic solvents such as methanol, dimethyl formamide (DMF), and ethylene glycol may be used. These solvents can grow the PEDOT particles during the heat treatment after coating the mixed solution to make the grain size of the PEDOT to an appropriate size can greatly improve the electrical properties.

Here, the volume ratio of the addition solvent: the conductive polymer solution may be 1: 20 to 3: 10. If the amount of the added solvent is less than 1: 20, it is difficult to improve the particle as much as desired, and if it is included more than 3 of 3: 10, the mixed solution may be diluted, which may be a problem when coating later.

The surfactant may include a nonionic surfactant, and the volume ratio of the nonionic surfactant to the conductive polymer solution may be 1: 200 to 1:10. If the non-ionic surfactant is included less than 1 in 1: 200, as described above, it may not function properly to uniformize the coating. In addition, when the non-ionic surfactant is added more than 1 of 1: 10, the non-ionic surfactants may aggregate with each other and may rather hinder the coating of the conductive polymer.

Subsequently, the mixed solution is coated on the polyethylene terephthalate substrate (S602). It can be formed by conventional wet coating methods of spin coating, flow coating, spray coating, dip coating, slit die coating and roll coating. This wet coating method is advantageous in that it is easy for mass production and low in equipment cost compared to the dry coating method.

Subsequently, the coated mixture solution is subjected to a heat treatment step (S603). Through this step (S603) it is possible to evaporate the solvent and the addition solvent contained in the mixed solution, and the morphology formation (conductive) of the conductive polymer. Conventional indium tin oxide requires a high temperature process of more than 300 ℃ to make a crystalline structure, in this embodiment, it is possible to form an electrode having high conductivity and transmittance even in a low temperature process (approximately, 90 ℃).

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the examples are only for illustrating the present invention, and the present invention is not limited thereto.

Example  One

To a glass vial was added 3 ml of a conductive polymer solution in which PSS and PEDOT (CLEVIOS PH 510, HC Starck) and 0.21 ml of dimethyl sulfoxide were added. This solution was stirred and 0.06 ml of Triton X-100 was added. This was placed in a voltex mixer and stirred again. This solution was coated with a bar coating on a polyethylene terephthalate substrate and heat treated for about 30 minutes in a heated stirrer heated to a temperature of about 90 ^° .

Example  2

An electrode was formed in the same manner as in Example 1, except that the coating was performed by spin coating.

Comparative example  One

An electrode was formed in the same manner as in Example 1 except that Triton X-100 was not added.

Comparative example  2

An electrode was formed in the same manner as in Example 2 except that Triton X-100 was not added.

7 to 10 show photographs for comparing coating states of the electrodes formed by Examples 1 and 2 and Comparative Examples 1 and 2. FIG. 7 is a photograph of the electrode surface formed by Example 1, Figure 8 is a photograph of the electrode surface formed by Comparative Example 1. 9 is a photograph of the electrode surface formed by Example 2, Figure 10 is a photograph of the electrode surface formed by Comparative Example 2.

First, referring to FIGS. 7 and 8, Example 1 and Comparative Example 1 both coated the electrode material with a bar coating, but Comparative Example 1 did not add Triton X-100. In Figure 7, it can be seen that in Example 1, the surface of the substrate is clean so that the coating is very uniform. On the other hand, the substrate surface of Comparative Example 1 in FIG. 8 looks like a stain, and it can be seen that the coating state is uneven.

9 and 10, both Example 2 and Comparative Example 2 coated the electrode material by spin coating, but Comparative Example 2 did not add Triton X-100. In Figure 9 it can be seen that Example 2 is a very uniform coating. In contrast, it can be seen that the surface of the substrate of Comparative Example 2 is not clean and the coating state is uneven in FIG. 10.

Therefore, it can be seen from the above results that the coating properties are improved by the addition of Triton X-100 regardless of the coating method.

Although not shown in the drawings, the electrodes formed by Examples 1 and 2 and Comparative Examples 1 and 2 were measured for transmittance using a Perkin-Elmer Lambda 12 UV / Vis spectrophotometer. The transmittance at 550 nm was measured to be about 88% in both Examples 1 and 2 and Comparative Examples 1 and 2 to confirm that addition of Triton X-100 did not reduce the transmittance of the electrode.

The electrode according to the above-described embodiment is applicable to all devices to which the electrode is applied, such as not only a touch panel but various display devices, light emitting devices, and solar cells.

The features, structures, effects and the like described in the foregoing embodiments are included in at least one embodiment of the present invention and are not necessarily limited to one embodiment. In addition, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

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 present invention. It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiments may be modified. It is to be understood that the present invention may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof.

30: electrode
31: PEDOT: PSS Complex
31a: polystyrene sulfonate (PSS)
31b: Poly (3,4-Ethylenedioxythiophene), PEDOT
32: surfactant
60: polyethylene terephthalate substrate

Claims (18)

Preparing a conductive polymer solution;
Mixing an additional solvent and a surfactant with the conductive polymer solution to form a mixed solution;
Coating the mixed solution on a substrate; And
Electrode forming method comprising the step of heat-treating the mixed solution. The method of claim 1,
In the preparing of the conductive polymer solution, an electrode forming method of mixing a solvent, a conductive polymer and a dopant. The method of claim 2,
The conductive polymer is formed of an electrode including at least one of polyethylene (3,4-Ethylenedioxythiophene, PEDOT), polyaniline, polypyrrole, polythiophene and derivatives thereof Way. The method of claim 2,
The dopant is at least one of polystyrene sulfonate (PSS), dodecylbenzene sulfonate (Dodecylbenzene sulfonate), toluene sulfonyl (Toluene sulfonyl), chemposulfonic acid, benzenesulfonic acid, hydrochloric acid and derivatives thereof. The method of claim 2,
Wherein the conductive polymer: the weight ratio of the dopant is 1: 0.01 to 1: 20 electrode formation method. The method of claim 2,
In the preparing of the conductive polymer solution,
An electrode forming method comprising 0.1 to 20% by weight of the conductive polymer and the dopant with respect to the conductive polymer solution. The method of claim 1,
The additive solvent includes at least one of dimethyl sulfoxide (DMSO) and N-Methyl-pyrrolidone (NMP). The method of claim 7, wherein
In the step of forming the mixed solution,
A method of forming an electrode, wherein the volume ratio of the added solvent: the conductive polymer solution is 1:20 to 3:10. The method of claim 1,
Wherein said surfactant comprises a non-ionic surfactant. 10. The method of claim 9,
The non-ionic surfactant includes at least one of saturated alcohol, polyoxyethylene glycol alkyl ester, polyoxyethylene glycol octyphenol ester, and polyoxyethylene glycol alkylphenol ester series. 10. The method of claim 9,
The non-ionic surfactant: the electrode formation method of the volume ratio of the conductive polymer solution is 1: 200 to 1: 10. The method of claim 1,
The substrate comprises a polyethylene terephthalate (poly (ethylene terephthalate), PET) film forming method. An electrode material comprising a conductive polymer, a dopant and a surfactant. The method of claim 13,
The conductive polymer is an electrode material including at least one of polyethylene (3,4-Ethylenedioxythiophene, PEDOT), polyaniline, polypyrrole, polythiophene and derivatives thereof . The method of claim 13,
The dopant is an electrode material comprising at least one of polystyrene sulfonate (PSS), dodecylbenzene sulfonate, toluene sulfonyl, chemposulfonic acid, benzenesulfonic acid, hydrochloric acid and derivatives thereof. 15. The method of claim 14,
The conductive material: the electrode material of the weight ratio of the dopant is 1: 0.01 to 1: 20. The method of claim 13,
Wherein said surfactant comprises a non-ionic surfactant. 18. The method of claim 17,
The non-ionic surfactant includes at least one of saturated alcohol, polyoxyethylene glycol alkyl ester, polyoxyethylene glycol octyphenol ester, and polyoxyethylene glycol alkylphenol ester series.

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