KR101884980B1 - Elcetrode structure including paper substrate, manufacturing method therof - Google Patents

Abstract

An electrode structure of an electronic device is disclosed. This includes a paper layer, a hydrophobic coating layer formed on the paper layer, a surface coating layer formed on the hydrophobic coating layer, and a metal layer formed on the surface coating layer. Such an electrode structure can be used as an electrode structure of a foldable electronic device at an economical cost by using paper. The laminated structure of the hydrophobic coating layer and the surface coating layer can be preferably applied to the foldable electronic device by preventing the polymer solution used as the surface coating layer from penetrating into the paper layer and providing higher flatness.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode structure including a paper substrate,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device field, and more particularly, to a foldable electrode structure including a paper substrate and a manufacturing method thereof.

A technique for manufacturing a foldable electrode structure for an electronic device using a paper substrate has been developed and used.

For example, as an example of the prior art, there is a method of forming a metal electrode by sputtering using a stencil mask on a paper substrate itself. Here, a small IC chip, an LED, a diode and the like are attached using an adhesive such as epoxy around the metal electrode. However, although such an electrode structure can be folded, there is a problem in that folding safety is poor.

Further, another example of the prior art is that a paper substrate is applied to an organic device. For example, there is an example in which parylene is coated on a copy paper, and Ni metal is formed by sputtering to prevent water absorption and improve surface roughness and conductivity. This example produced a top-emitting organic device in this manner, although the efficiency is poor. As a similar example of prior art, it has been reported that the efficiency of the entire organic light emitting device is improved by coating the copy paper with parylene and SiO ₂ and then sputtering Ni metal.

As another example of the prior art, research has been reported on the production of organic solar cells using tracing paper. This is not as efficient as a glass-based device / module, but it also exhibits folded or warped behavior. Here, a photoactive layer structure of an organic molecule donor / acceptor formed by applying a conductive polymer material by an oxidative vapor-patterned CVD process on a paper substrate and spin coating process was used.

The transparency is limited due to the characteristics of the paper substrate. Therefore, when the organic light emitting device is manufactured, the whole light emitting method is suitable. The structure of an organic light emitting device applicable to a metal foil substrate, which is a typical opaque substrate, is a structure in which aluminum (Al) is deposited as a reflective electrode (anode) on a substrate, molybdenum trioxide (MoO ₃ ) is used as a charge injection layer, Tris- (8-hydroxy-quinoline) aluminum (Alq ₃ ) was deposited as an electron transport layer and a light emitting layer, and a transparent electrode Lithium fluoride (LiF), aluminum (Al), and silver (Ag) are sequentially deposited on the substrate (anode). In order to produce such an organic electronic device on a paper substrate, surface roughness control through surface modification of a paper substrate is a top priority. Also, high reflectivity and low resistance of fabricated electrodes are required.

Korean Patent Publication No. 10-2012-0035998

SUMMARY OF THE INVENTION The present invention has been made in view of the problems of the prior art described above, and provides an electrode structure including a paper substrate having excellent folding stability.

The present invention also provides a method of manufacturing the above-described improved electrode structure.

The present invention also provides an organic light emitting device comprising the above-described improved electrode structure.

The present invention provides an electrode structure for an electronic device comprising: a paper layer; A hydrophobic coating layer formed on the paper layer; A surface coating layer formed on the hydrophobic coating layer; And a metal layer formed on the surface coating layer.

The paper layer may be pulp-based paper, and the hydrophobic coating layer may include a surface roughness reducing layer and a hydrophobicity imparting layer.

The paper layer may be a polymer-based paper.

The present invention also provides an organic light emitting device comprising: a first electrode layer comprising a paper layer; An organic layer formed on the first electrode layer; And a second electrode layer formed on the organic layer, wherein the first electrode layer includes a paper layer, a hydrophobic coating layer formed on the paper layer, a surface coating layer formed on the hydrophobic coating layer, and a metal layer formed on the surface coating layer do.

The present invention also provides a method for manufacturing an electrode structure for an electronic device comprising a paper substrate, comprising the steps of: (a) forming a hydrophobic coating layer on a paper layer; (b) forming a surface coating layer on the hydrophobic coating layer; And (c) forming a metal layer on the surface coating layer, wherein the surface coating layer can be formed through a solution process.

The step (a) may include a first coating step of forming a surface roughness reducing layer on the paper layer and a second coating step of forming a hydrophobicity imparting layer.

The primary coating process may use a material including clay and CaCO ₃ .

The second coating process may use a material including siloxane, ethylene oxide polymer, and water repellent agent.

The surface coating layer may be poly (pyromellitic dianhydride-co-4,4'-oxydianiline).

According to the present invention, a foldable electrode structure for an electronic device and a method of manufacturing the same are provided. The electrode structure of the present invention has a hydrophobic coating layer on a paper substrate so that the surface coating layer formed thereon is not absorbed by the paper substrate itself. As a result, the flatness of the surface coating layer can be ensured and excellent folding stability can be obtained, which can be preferably applied as an electrode structure of various foldable electronic devices. Furthermore, the hydrophobic coating layer formed on the paper substrate of the present invention includes the surface roughness reducing layer and the hydrophobicity imparting layer, and finally the surface coating layer having excellent flatness and the metal layer can be formed thereon. Therefore, folding stability, conductivity, reflectance, and the like can be improved.

1 is a cross-sectional view schematically showing an electrode structure according to the present invention.
2A to 2F are photographs showing surface roughness of the paper layer 10 according to Comparative Examples and Examples 1 to 5, respectively, according to the presence or absence of the surface coating layer 30. FIG.
3A to 3E are images of the folded portions of the electrode structures formed by depositing the metal layer 40 on the paper substrate shown in FIGS. 2A to 2E by thermal evaporation and forming the reflective electrodes at an angle of +180 degrees.
4 is a graph showing the sheet resistance of the reflective electrode in Comparative Examples and Examples 1 to 5. FIG.
5 is a graph showing the reflectance of the reflective electrode of the electrode structure of Comparative Examples and Examples 1 to 5. FIG.
6 is a graph showing the conductivity of the electrode structure of Comparative Examples and Examples 1 to 5 after extreme folding.
FIG. 7 is a graph showing electrode stability according to Comparative Example and Examples 1 to 5 according to repetitive folding. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

As technology develops, electronics become lighter and cheaper, and there is a greater desire for foldable form and structure. Recently, researches for utilizing paper substrates have been actively carried out. Paper can be folded differently from conventional glass substrates or silicon substrates, and is lightweight, inexpensive, and easy to use after use. Accordingly, the paper substrate will be applied to various fields such as a light emitting device field and a display field. The present invention forms a hydrophobic coating layer on a paper substrate, and then forms a surface coating layer on the surface of which a surface roughness can be controlled. This suppresses the water absorbency of the paper substrate and prevents the surface coating layer from being absorbed into the paper substrate, so that the flatness can be secured. Thus, the folding stability of the metal layer formed thereon is improved, and as a result, the reflectance and the conductivity are improved. The present invention provides suitable materials for hydrophobic coatings, suitable coating processes, and suitable polymeric materials for use in surface roughness control.

1 is a cross-sectional view schematically showing an electrode structure according to a preferred embodiment of the present invention.

The electrode structure of an electronic device according to the present invention includes a paper layer 10, a hydrophobic coating layer 20, a surface coating layer 30, and a metal layer 40.

Examples of paper layers 10 that are preferably applied in the present invention may include pulp based paper or polymer based paper.

When the paper layer 10 is pulp-based paper, the hydrophobic coating layer 20 may include a surface roughness reducing layer 210 and a hydrophobicity imparting layer 220 formed thereon. The surface roughness reducing layer 210 may be formed of a material including clay and CaCO ₃ and the hydrophobicity imparting layer 220 may be formed of a material including siloxane, ethylene oxide polymer, and water repellent agent . The primary coating is made of paper made of pulp because the paper is intertwined with the fibrous structure. The secondary coating provides shielding and hydrophobicity to prevent destruction of the primary coating layer or penetration and diffusion into the paper layer when a material containing a strong organic solvent is formed on the paper layer. The first and second coatings are prepared by dispersing the materials required for coating in water in appropriate proportions and then coating the desired amount of paper on the surface of the roll paper using blades, rods, air knives, rollers, etc., followed by hot air dryer, , An IR dryer, or the like, so that a coating layer of a solid content containing an appropriate moisture of 3 to 6% of the final moisture is formed on the paper.

The hydrophobic coating layer 20 is interposed between the paper layer 10 and the surface coating layer 30 to prevent the surface coating layer 30 formed of a polymer from being absorbed into the paper layer 10 and further to prevent the surface coating layer 30 ) Is further increased.

A preferred example of the surface coating layer 30 employed in the present invention may be, for example, poly (pyromellitic dianhydride-co-4,4'-oxydianiline), and these materials have the advantage of good interfacial adhesion. In addition, since the heat resistance / chemical resistance is good, when the electrode layer or the like is formed on the electrode layer by thermal evaporation, the paper substrate can be prevented from being damaged or damaged by being exposed to the heat, It is chemically stable and can suppress the damage of the paper layer. In addition, when poly (pyromellitic dianhydride-co-4,4'-oxydianiline) applied to the surface coating layer 30 of the present invention is applied to a paper substrate having a hydrophobic surface, the folding stability is remarkably improved.

When the paper layer 10 is a polymer-based paper, the formation process of the surface roughness reducing layer may be omitted, and a hydrophobic coating layer for imparting hydrophobicity may be formed on the paper layer 10.

The electrode structure of the present invention can be applied to a reflective electrode of an organic light emitting device, for example. In this case, the organic light emitting device may include a first electrode layer including a paper layer, an organic layer formed on the first electrode layer, and a second electrode layer formed on the organic layer.

Here, the electrode structure of the present invention is applied to the first electrode layer to realize the reflective electrode of the foldable organic light emitting device as described above.

Hereinafter, a method of manufacturing an electrode structure for an electronic device including the paper substrate of the present invention will be described.

A method of manufacturing an electrode structure for an electronic device including a paper substrate of the present invention includes forming a hydrophobic coating layer (20) on a paper layer.

In the case where the paper layer 10 is pulp-based paper, the hydrophobic coating layer 20 is formed by a first coating process for forming the surface roughness reducing layer 210 on the paper layer 10 and a hydrophobicity imparting layer 220 formed thereon And a second coating process. The primary coating process may be to form the surface roughness reducing layer 210 using a material including clay and CaCO ₃ . In the secondary coating process, the hydrophobicity imparting layer 220 is formed on the surface roughness reducing layer 210 by using a material including siloxane, ethylene oxide polymer, and water repellent agent.

When the paper layer 10 is a polymer-based material, a hydrophobic coating layer that imparts hydrophobicity can be formed on the paper layer without separately forming a surface roughness reducing layer. The hydrophobic coating layer that can be applied at this time may be a material of poly ethylene series.

Next, the step of forming the surface coating layer 30 on the hydrophobic coating layer 20 is carried out.

The surface coating layer 30 is formed of poly (pyromellitic dianhydride-co-4,4'-oxydianiline) as described above. In the present invention, the surface coating layer 30 can be formed through a solution process. Since the manufacturing method of the present invention includes the hydrophobic coating layer 20, even if the surface coating layer 30 is formed thereon through a solution process, the surface coating layer 30 is prevented from being absorbed into the paper layer 10, Can be obtained.

Next, a metal layer 40 is formed on the surface coating layer 30. The metal layer 40 may be formed, for example, of silver (Ag), which may utilize thermal deposition.

Hereinafter, embodiments of the present invention and comparative examples will be compared and described.

[Comparative Example]

In the comparative example, a reflective electrode was formed on a paper layer having no hydrophobic coating layer and a surface coating layer to prepare an electrode structure.

Commercial paper (copy paper) was used as the paper layer 10, dried in an oven at 80 ° C. for 24 hours, and then silver was deposited at a rate of 1 Å / sec to a thickness of 100 nm using a thermal deposition process, . The reflective electrode was fabricated on a 2.5 cm * 2.5 cm paper substrate with a size of 2.5 cm * 1 cm and the reflectance was measured using a Uv-vis instrument. To confirm the folding stability, folding was performed ten times at angles of -180 °, -90 °, +90 ° and +180 °, and the conductivity was measured and compared.

[Example 1]

In Example 1, a commercial copy paper was used as the paper layer 10, and the paper layer 10 was dried in an oven at 80 ° C. for 24 hours, and then a poly (pyromellitic dianhydride- co-4,4'-oxydianiline solution was spin-coated at a speed of 4,000 rpm for 60 seconds to form a surface coating layer 30, and the solvent was removed at 100 ° C for 1 hour in the air. Then, a metal layer 40) to form a reflective electrode. The reflective electrode was formed by depositing silver with a thickness of 100 nm at a rate of 1 ANGSTROM / sec and a 2.5 cm * 1 cm size on a 2.5 cm * 2.5 cm paper substrate. The reflectance was measured using Uv-vis equipment. In order to confirm the folding stability, ten folds were folded at an angle of -180 °, -90 °, +90 ° and +180 °, and the conductivity was measured after the folding.

[Example 2]

In Example 2, a polymer-based paper layer 10 having a hydrophobic coating layer 20 on its surface was dried in an oven at 80 ° C for 24 hours, and then a reflective electrode was formed of the metal layer 40 without forming a surface coating layer. The reflective electrode was formed by depositing 100 nm of silver at a rate of 1 Å / sec, and was fabricated on a paper substrate of 2.5 cm * 2.5 cm with a size of 2.5 cm * 1 cm. The reflectance was measured using Uv-vis equipment. In order to confirm the folding stability, the conductivity was measured after folding 10 times at -180 °, -90 °, +90 °, +180 °, and compared. In order to check the stability of repeated folding, Respectively.

[Example 3]

In Example 3, a polymer-based paper layer 10 having a hydrophobic coating layer 20 on its surface was dried in an oven at 80 ° C. for 24 hours, and then a poly (pyromellitic dianhydride-co-4,4'-oxydianiline) To form a surface coating layer 30. The solvent was then removed from the surface coating layer 30 by a metal layer 40 to form a reflective electrode. The reflective electrode was formed by depositing 100 nm of silver at a rate of 1 Å / sec, and was fabricated on a paper substrate of 2.5 cm * 2.5 cm with a size of 2.5 cm * 1 cm. The reflectance was measured using Uv-vis equipment. In order to confirm the folding stability, the conductivity was measured after folding 10 times at -180 °, -90 °, +90 °, +180 °, and compared. In order to check the stability of repeated folding, Respectively.

[Example 4]

Example 4 is a process for forming a hydrophobic coating layer 20 including a surface roughness reducing layer 210 and a hydrophobicity imparting layer 220 on a pulp-based paper layer 10, After drying, a reflective electrode was formed of the metal layer 40 without forming a surface coating layer. The reflective electrode was formed by depositing 100 nm of silver at a rate of 1 Å / sec, and was fabricated on a paper substrate of 2.5 cm * 2.5 cm with a size of 2.5 cm * 1 cm. The reflectance was measured using Uv-vis equipment. In order to confirm the folding stability, the conductivity was measured after folding 10 times at -180 °, -90 °, +90 °, +180 °, and compared. In order to check the stability of repeated folding, Respectively.

[Example 5]

In Example 5, after the hydrophobic coating layer 20 including the surface roughness reducing layer 210 and the hydrophobicity imparting layer 220 was formed on the pulp-based paper layer 10, the resultant was dried in an oven at 80 ° C for 24 hours After drying, a poly (pyromellitic dianhydride-co-4,4'-oxydianiline) solution was spin-coated at a speed of 4,000 rpm for 60 seconds to form a surface coating layer 30, and then the solvent was removed at 100 ° C for 1 hour A reflective electrode was formed of the metal layer (40). The reflective electrode was formed by depositing 100 nm of silver at a rate of 1 Å / sec, and was fabricated on a paper substrate of 2.5 cm * 2.5 cm with a size of 2.5 cm * 1 cm. The reflectance was measured using Uv-vis equipment. In order to confirm the folding stability, the conductivity was measured after folding 10 times at -180 °, -90 °, +90 °, +180 °, and compared. In order to check the stability of repeated folding, Respectively.

FIGS. 2A to 2F are photographs of surface roughness of the paper layer 10 in Comparative Examples and Examples 1 to 5, respectively, according to the presence or absence of the surface coating layer 30. FIG. 2A corresponds to a comparative example, and Figs. 2B to 2F correspond to Examples 1 to 5, respectively.

Three types of paper substrates were used in the comparative examples and the examples. The three types of paper substrates used were a pulp-based paper layer (commercial copy paper) without a hydrophobic coating layer, a polymer-based paper layer with a hydrophobic coating layer, and a pulp-based paper layer with a hydrophobic coating layer.

The surface roughness of these three types of paper substrates according to the presence or absence of the surface coating layer 30 is analyzed using Atomic Force Microscopy (AFM), and these are shown in a 3D image in FIGS. 2A to 2F.

2b, 2d and 2f in which the surface coating layer 30 was formed, the paper substrate was subjected to moisture removal in an oven at 80 deg. C for 24 hours, and then a poly (pyromellitic dianhydride-co-4,4'-oxydianiline) rpm for 60 seconds and the solvent was removed in air at 100 占 폚 for 1 hour. The surface roughness of the surface of the paper substrate on which the surface coating layer 30 is formed is remarkably reduced. However, it can be seen that the solution for forming the surface coating layer 30 is absorbed by the paper substrate itself and the effect is reduced because the surface of the copy paper having no hydrophobic coating layer is different from that of the surface treated with the water repellent treatment (with the hydrophobic coating layer). On the other hand, in the case of the pulp-based paper layer / hydrophobic coating layer / surface coating layer, the surface is very stable, and thus a preferable organic light emitting device can be produced.

3A to 3H are images obtained by depositing the metal layer 40 by thermal evaporation to form the reflective electrode and the electrode structures of Examples 1 to 5 at the folded portion after folding at +180 degrees. The electrode structure was folded at an angle of +180 degrees and the unfolded state was repeated ten times to show the folded portion.

In the case of the electrode structure using the copy paper (Comparative Example of Fig. 3A and Example 1 of Fig. 3B), the roughness of the cellulose was revealed as it was, and the conductivity was not measured when folded at an angle of +180 degrees. Also in the case of Example 2 in which the surface coating layer 30 is not provided among the polymer-based paper layers having hydrophobic coating layers (Examples 2 and 3), the electrode itself is not formed well due to the high surface roughness of the paper substrate, All of the connections between the reflective electrodes were cut off and failed to measure resistance. On the other hand, in Example 3 in which the surface coating layer 30 was formed on the polymer-based paper layer and in the case of the pulp-based paper layer having the hydrophobic coating layer (Example 4 and Example 5), the electrode of the folded portion was torn and stretched, When the electrode was folded again after folding, the electrode was maintained as it was, and it was confirmed that the conductivity did not decrease significantly even after 1000 repetitions.

4 is a graph showing the sheet resistance of the reflective electrode in Comparative Examples and Examples 1 to 5. FIG. The sheet resistance was measured using a 4-probe sheet resistance measuring instrument. Five samples were prepared and the average value was measured 10 times per sample.

The results of the measurement are 10.1843 ohm / sq, 2.39282 ohm / sq, 6.20822 ohm / sq, 1.20532 ohm / sq, And a sheet resistance of 0.99386 ohm / sq. When the coating of the surface coating layer 30 (Examples 1, 3, and 5) was performed, the decrease in sheet resistance was confirmed in all the paper samples.

5 is a graph showing the reflectance of the reflective electrode of the electrode structure of Comparative Examples and Examples 1 to 5. FIG. In the case of Examples 1, 3 and 5 having the surface coating layer 30, the reflectance was relatively improved. Particularly, the polymer-based paper layer 10 having the stable hydrophobic coating layer 20 and the pulp having the hydrophobic coating layer 20 Based paper layer 10, the increase in the reflectance is remarkable.

6 is a graph showing the conductivity of the electrode structure of Comparative Examples and Examples 1 to 5 after extreme folding.

The relative conductivities were compared by measuring the resistance of the connecting electrodes by folding ten times from the inner extremely folded state (-180 degrees) to the outer extreme folded state (+180 degrees). In the case of the comparative example using the commercial copy paper and the case of the example 1, it was confirmed that the electrode was cut off in the extremely folded state and the conductivity did not flow. In Example 3 in which the unstable characteristics were shown in Example 2 but the surface coating layer was formed, the conductivity was measured even after the extreme folded state. In Examples 4 and 5, the electrode was not broken even in the extremely folded state, and the flow of conductivity was confirmed. In the case of Example 5, the performance was very stable.

FIG. 7 is a graph showing electrode stability according to Comparative Example and Examples 1 to 5 according to repetitive folding. FIG.

In the case of Comparative Example, Example 1 and Example 2, measurement was impossible due to breakage of the electrode at +180 degrees, and evaluation was made for Examples 3, 4, and 5. The conductivity was measured while folded at an angle of +180 degrees (Examples x-F), and the conductivity was measured again after the original state was restored (Example x-S). The measurements were made at 1, 3, 5, 10, 20, 30, 50, 100, 200, 300, 500, and 1,000 times. Five samples were prepared for each sample. As shown in the drawing, in Example 3, the conductivity is shown even after 1000 measurements in the edged state, but the conductivity is not measured after 200 times in the folded state. In the case of Example 4, it can be confirmed that the conductivity becomes zero at a predetermined number of times or more. However, in the case of Example 5, it was confirmed that the conductive property was stable up to 1,000 times in both the folded state and the flat state.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

10: paper layer 20: hydrophobic coating layer
210: Surface roughness reducing layer 220: Hydrophobicity imparting layer
30: surface coating layer 40: metal layer

Claims (9)

An electrode structure for a foldable electronic device comprising:
A pulp-based paper layer;
A hydrophobic coating layer composed of a surface roughness reducing layer formed on the paper layer and a hydrophobic imparting layer formed on the surface roughness reducing layer;
A surface coating layer formed on the hydrophobic coating layer; And
And a metal layer for electrodes formed on the surface coating layer,
The hydrophobic coating layer is formed using water as a solvent. The surface roughness reducing layer is formed of a material containing clay and CaCO3. The hydrophobic imparting layer is formed of a material including siloxane, ethylene oxide polymer, and water repellent agent Wherein the surface coating layer is formed of poly (pyromellitic dianhydride-co-4,4'-oxydianiline) using a solution process.
delete delete delete A method for manufacturing an electrode structure for a foldable electronic device comprising a paper substrate,
(a) forming a hydrophobic coating layer consisting of a surface roughness reducing layer and a hydrophobicity imparting layer on a pulp-based paper layer;
(b) forming a surface coating layer on the hydrophobic coating layer by a solution process; And
(c) forming a metal layer for the electrode on the surface coating layer,
Wherein the hydrophobic coating layer is formed using water as a solvent and the surface roughness reducing layer is formed of a material including clay and CaCO3, and the hydrophobic imparting layer is formed of a material including siloxane, ethylene oxide polymer, and water repellent agent And the surface coating layer is formed of poly (pyromellitic dianhydride-co-4,4'-oxydianiline) by using a solution process. delete delete delete delete

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