KR20200045395A - Graphene laminate with improved bendability, method for manufacturing same, eletrode material using same, and electronic device - Google Patents

Abstract

Provided are a graphene laminate with improved bendability, a manufacturing method thereof, an electrode material using the same, and an electronic device. The present invention provides the graphene laminate, including: a basic material; a first layer arranged on the basic material and including graphene; and a second layer arranged on the first layer and including a conductive high molecule and a binder resin, thereby allowing the graphene layer to be protected from the outside, complementing electrical conductivity, and having improved durability and bendability.

Description

Graphene laminate with improved bending resistance, manufacturing method thereof, and electrode material and electronic device using the same {GRAPHENE LAMINATE WITH IMPROVED BENDABILITY, METHOD FOR MANUFACTURING SAME, ELETRODE MATERIAL USING SAME, AND ELECTRONIC DEVICE}

The present invention relates to a graphene laminate having improved flex resistance, a method for manufacturing the same, an electrode material using the same, and an electronic device.

Graphene is a carbon allotrope having a structure in which carbon atoms are arranged in a two-dimensional hexagonal shape. Since carbon atoms are sp ² hybrids, they are not only structurally and chemically stable, but also have excellent electrical and thermal conductivity, high mechanical strength, and flexibility at the same time. Therefore, it can be used in various forms such as graphite stacked in three dimensions, carbon nanotubes rolled in one dimension, or ball-shaped fullerenes with a zero-dimensional structure.

In particular, the graphene film produced using graphene has flexibility and electrical conductivity and transparency, and thus is used in transparent electrode materials in display elements, touch panels, and organic solar cells, or in organic solar cells, secondary cells, and fuel cells. Its application as an energy electrode material has been actively studied. Furthermore, the application area of the graphene film is not limited to the above-mentioned fields, and is expanding to semiconductor materials or gas barrier films in various devices such as memory devices, biosensors, and organic thin film transistors.

The present invention is described; A first layer including graphene disposed on the substrate; And a second layer including a conductive polymer and a binder resin disposed on the first layer, so that the graphene layer is protected from the outside, supplements electrical conductivity, and provides a graphene laminate with improved durability and flex resistance. do.

According to one aspect,

materials;

A first layer disposed on the substrate and including graphene; And

A graphene laminate is provided on the first layer and includes a second layer including a conductive polymer and a binder resin.

According to another aspect,

Forming a first layer comprising graphene on a substrate;

Applying a coating composition comprising a conductive polymer, a binder resin, and a solvent on the first layer; And

Forming a second layer including the conductive polymer and the binder resin by removing at least a portion of the solvent in the coating composition;

Provided is a method of manufacturing a graphene laminate, including.

According to another aspect, an electrode material including the graphene laminate is provided.

According to another aspect, an apparatus including an electrode using the electrode material is provided.

According to one embodiment, a graphene layer is provided in which the graphene layer is protected from the outside, supplements electrical conductivity, and improves durability and flex resistance.

1 shows the results of evaluation of flexural resistance of the graphene laminates of Examples 1 to 4 and the graphene laminates of Comparative Example 1 according to one embodiment.

Hereinafter, detailed contents and possible implementations for carrying out the present invention will be described. However, with respect to the configuration not specifically described below, unless contrary to the object of the present invention, the contents known in the art may be applied.

In this specification, when a layer or member is said to be located “on” another layer or member, this means that another layer or member or another layer between the two layers or members, as well as when the layer or member is in contact with the other layer or member, or This includes the case where another member is present.

In addition, when a part of the present specification “includes” a certain component, this means that other components may be further included instead of excluding other components, unless otherwise stated.

[Graphene laminate]

Graphene laminate according to an embodiment of the present invention,

materials;

A first layer disposed on the substrate and including graphene; And

It is disposed on the first layer, and includes a second layer including a conductive polymer and a binder resin.

The substrate may be used without limitation, various types of substrates known in the art, as long as it does not contradict the object of the present invention.

According to one embodiment, the substrate is a polymer film, polyethylene terephthalate (polyethyleneterephthalate, PET), polyethylene (polyethylene, PE), polypropylene (polypropylene, PP), polycarbonate (polycarbonate, PC), polymethyl methacrylate (poly (methyl methacrylate), PMMA), polyimide (PI), oriented polypropylene (OPP), biaxially oriented polypropylene (BOPP), polyethylene 2,6-dicarboxynaphthalate (polyethylene 2,6-dicarboxyl naphthalate, PEN), polyethersulfone (PES), polyester (polyester, PE) or polystyrene (polystyrene, PS). For example, the substrate may be PET.

According to one embodiment, the substrate may be flexible.

Among the first layers, a substrate having various thicknesses may be used as necessary, and is not particularly limited. For example, the thickness of the substrate may be 0.1 μm to 200 μm.

The graphene laminate is disposed on the substrate and includes a first layer including graphene.

In the present specification, “graphene” refers to a structure in which a plurality of carbon atoms are connected to each other by sp ² -sp ² bonds to form a ring. The graphene may be a two-dimensional single layer or a structure including multiple layers in which several of these single layers are stacked.

The ring formed by the carbon atoms among the graphene is generally a 6-membered ring composed of 6 carbon atoms, but may be a 5-membered ring composed of 5 carbon atoms or a 7-membered ring composed of 7 carbon atoms. The graphene may also include atoms other than carbon, for example, atoms such as N, O, S, and Si instead of some of the carbon atoms.

Among the graphene, graphene having a relatively high proportion of a six-membered ring structure composed only of carbon is generally referred to as high-quality graphene, and has high crystallinity, transparency, and electrical conductivity.

According to one embodiment, the graphene included in the first layer may include at least one selected from CVD graphene, graphene oxide (GO) and reduced graphene oxide (rGO). You can.

The "CVD graphene" means graphene formed by a chemical vapor deposition method. The chemical vapor deposition method may use a method known in the art, and for example, an apparatus such as an induced coupled plasma (ICP).

The CVD graphene includes high-quality graphene as described above. However, the CVD graphene is not a monocrystalline structure arranged in the same direction as the atoms are regularly arranged, but because the atoms are arranged regularly but have a polycrystalline structure composed of several parts having different directions. The electrical and mechanical properties of the graphene surface are lower than that of the single crystal structured graphene.

In this specification, "graphene oxide (graphene oxide)" refers to a compound in which the graphene is oxidized. Since the graphene oxide is a polar material having a functional group such as an epoxy group, a carbonyl group, a carboxyl group, a hydroxyl group, etc., it has excellent dispersibility in a solvent, but it must be reduced back to graphene in order to obtain desired properties such as electrical conductivity.

In the present specification, "reduced graphene oxide" means graphene obtained by reducing the graphene oxide using a thermal reduction method or a chemical reduction method.

The reduction of graphene oxide is Yes because the production by way of which after reducing it back to the oxidation of the pin, well formed a variety of functional groups other than the hydrocarbon group in the pin, sp ² addition sp ³ carbon chemical vapor deposition such that a plurality formation (Chemical Vapor Deposition: CVD) shows a different irregular structure from the graphene.

The irregular structure of the reduced graphene oxide may be generally expressed as a D / G (I _D / I _G ) value obtained by analyzing a Raman spectrum. For example, the reduced graphene oxide in the present specification may have a D / G ratio of 0.8 to 1.2 according to the Raman spectrum.

Since the reduced graphene oxide can be prepared through a solution process, a large amount of reduced graphene oxide can be obtained at a relatively low process cost, which is economical. For example, the graphene oxide can be coated on a substrate and then thermally reduced to produce reduced graphene oxide.

In this specification, the shape of the graphene is not particularly limited. For example, the graphene may have a form of a film, flake, particle, or paste.

According to one embodiment, the graphene may be CVD graphene or graphene flake in the form of a film formed by chemical vapor deposition, and may be suitably applied to a laminate in consideration of productivity and conductivity.

The graphene laminate of the present invention, by introducing a second layer containing a conductive polymer and a binder resin on the first layer containing the graphene, while effectively supplementing the properties of the graphene as described above, the graphene layer It can protect from the outside, complement the electrical conductivity, and improve durability and flex resistance.

The thickness of the graphene may be 0.1 nm to 10 nm, but the thickness is not limited in a range that does not impair the electrical conductivity, durability or bending resistance of the graphene laminate. According to one embodiment, the graphene may be a single-layer graphene, and the thickness of the single-layer graphene may be 0.1 nm to 0.5 nm.

According to another embodiment, the first layer of the graphene laminate may have a film form.

The thickness of the first layer is not particularly limited in a range that does not impair the electrical conductivity, durability or bending resistance of the graphene laminate. According to one embodiment, the thickness of the first layer may be 1 nm to 100 μm, for example, 10 nm to 10 μm.

(2nd floor)

The graphene laminate includes a second layer disposed on the first layer. The second layer complements the electrical conductivity and durability of the first layer, and serves as an overcoating layer that improves flex resistance while protecting the first layer from the outside.

The expression that the second layer is disposed on the first layer has a different configuration between when the first layer and the second layer are in contact with, and between the first layer and the second layer. It is meant to include all of the intervening cases. According to one embodiment, the first layer and the second layer may be in direct contact, but are not limited thereto.

The second layer includes a conductive polymer and a binder resin.

As the conductive polymer, various conductive polymers known in the technical field of the present invention can be used, and is not particularly limited.

According to one embodiment, the conductive polymer

Polyphenylene, polyfluorene, polypyrene, polyazulene, polynaphthalene,

Polypyrrole [poly (pyrrole)], polycarbazole, polyindole, polyazepine, polyaniline,

Polythiophene, poly (3,4-ethylenedioxythiophene); PEDOT], poly (p-phenylene sulfide): PPS,

Polyacetylene [poly (acetylene)], poly (p-phenylene vinylene) [poly (p-phenylene vinylene)] and derivatives thereof;

It may include any one selected from or any combination thereof.

According to one embodiment, the conductive polymer may be PEDOT, polyaniline or polypyrrole. The conductive polymer is included in the second layer, so that the electrical conductivity of the first layer can be supplemented and improved.

According to one embodiment, the conductive polymer may be doped with a water-soluble polymer. For example, the water-soluble polymer may be polystyrene sulfonate (PSS), and the conductive polymer may be PEDOT: PSS.

The water-soluble polymer may serve as a dopant that improves electrical conductivity of the conductive polymer by doping the conductive polymer to form an ionic complex.

According to one embodiment, per 100 parts by weight of the second layer, the content of the conductive polymer may be 60 parts by weight to 98 parts by weight, for example, 70 parts by weight to 96 parts by weight. When the content of the conductive polymer is 80 parts by weight or more, particularly 85 parts by weight or more, the electrical conductivity of the graphene laminate can be secured to a desired level, and transparency is lowered when 90 parts by weight or more, particularly 98 parts by weight or more It may not be suitable for forming a coating layer.

The binder resin serves as a support so that the second layer of the graphene laminate can maintain the form of a coating film.

According to one embodiment, the binder resin may include polyester, polyurethane, acrylic resin, acrylic urethane resin, polyvinyl alcohol, or any combination thereof. For example, the binder resin may include polyvinyl alcohol.

According to one embodiment, per 100 parts by weight of the second layer, the content of the binder resin may be 0.01 parts by weight to 10 parts by weight, for example, 0.05 parts by weight to 5 parts by weight. When the content of the binder resin is within the above-described range, mechanical properties of the first layer may be maintained or improved.

The polyvinyl alcohol may be used having a variety of saponification and molecular weight range, it may be obtained from commercially available manufacturers.

The polyvinyl alcohol may protect the first layer by improving the coating property of the second layer with respect to the first layer.

According to one embodiment, the degree of saponification of the polyvinyl alcohol may be 88% to 92%. When the saponification degree range of the polyvinyl alcohol is satisfied, while maintaining the solubility of the polyvinyl alcohol in a solvent at a certain level or more, it is possible to prevent a phenomenon in which the surface tension is excessively low due to strong hydrogen bonding between polyvinyl alcohol molecules. You can.

According to one embodiment, the molecular weight of the polyvinyl alcohol may be 25,000 g / mol to 100,000 g / mol, for example, 50,000 g / mol to 100,000 g / mol. When the molecular weight range of the polyvinyl alcohol is satisfied, the surface tension and viscosity are maintained at an appropriate level to form a coating layer.

According to one embodiment, in the second layer, the content of the polyvinyl alcohol per 100 parts by weight of the conductive polymer may be 0.1 parts by weight to 5 parts by weight.

According to one embodiment, the content of the polyvinyl alcohol per 100 parts by weight of the second layer may be 0.01 parts by weight to 10 parts by weight, for example, 0.05 parts by weight to 5 parts by weight.

According to one embodiment, the second layer may further include an auxiliary dopant.

The auxiliary dopant is dimethylsulfoxide (dimethylsulfoxide: DMSO), N-methylpyrrolidinone (NMP), N, N-dimethylformamide (DMF), N-methylacetamide ( N-methylacetamide (NMAA), N-dimethylacetamide (DMA), N-methylpropionamide (NMPA), or any combination thereof.

For example, the auxiliary dopant may be DMSO. The auxiliary dopant may improve the electrical conductivity of the conductive polymer.

According to one embodiment, the thickness of the second layer may be 10 nm to 1000 nm, for example, 100 nm to 600 nm, and for example, 400 nm to 600 nm. For another example, the thickness of the second layer may be 10 nm to 800 nm, or 100 nm to 600 nm, or 200 nm to 400 nm.

According to another embodiment, the transmittance of the graphene laminate may be 90% to 95%. That is, the graphene laminate does not lower transparency while compensating for the physical properties of the graphene surface.

According to another embodiment, the surface roughness of the graphene laminate may be 1.0 nm to 10.0 nm.

[Method of manufacturing graphene laminate]

Method of manufacturing a graphene laminate according to an embodiment

Forming a first layer comprising graphene on a substrate;

Applying a coating composition comprising a conductive polymer, a binder resin, and a solvent on the first layer; And

And removing at least a portion of the solvent in the coating composition to form a second layer including the conductive polymer and the binder resin.

The graphene may include at least one selected from CVD graphene, graphene oxide (GO) and reduced graphene oxide (rGO) as described above, and the type of the graphene Accordingly, the step of forming the first layer can be appropriately selected.

According to one embodiment, the graphene includes CVD graphene, and forming the first layer is performed by chemical vapor deposition of a carbon source (eg, methane, etc.) on the first layer on the substrate. And growing the CVD graphene layer.

According to another embodiment, the graphene includes reduced graphene oxide, and the forming of the first layer includes applying a solution including graphene oxide and a solvent on the first layer (a); And reducing the graphene oxide to form a first layer including the reduced graphene oxide (b).

For example, the concentration of the graphene oxide per 100 parts by weight of the solution containing the graphene oxide and the solvent may be 0.02% to 0.2%, or 0.03% to 0.1%. When the concentration of the graphene oxide is 0.03% or more, the surface resistance value is kept low, and when it is 0.1% or more, the transparency of the graphene laminate is lowered.

According to one embodiment, the step (a) of applying a solution containing graphene oxide and a solvent on the first layer is performed by dip coating the substrate using a solution containing the graphene oxide and a solvent. Can be.

For example, graphene oxide may be coated on the substrate by immersing the substrate in a solution containing the graphene oxide and a solvent for 30 seconds to 30 minutes. The shorter the immersion time, the better the transmittance of the graphene laminate.

However, the step (a) of applying a solution containing graphene oxide and a solvent on the first layer is not limited to the above-described dip coating method, and spin coating, spray coating, dip coating, and slit It may be performed by a method such as coating, slot die coating, bar coating, or the like.

According to one embodiment, the solution including the graphene oxide and the solvent applied on the first layer may be hot-air dried at a temperature of 50 ° C to 100 ° C.

However, the step of forming the first layer including the graphene is not limited to the above-described embodiment, for example, by adjusting the concentration of the graphene, the coating method, the time required for the process, or the temperature at which the process is performed. Properties of the graphene laminate of the present invention, such as transmittance, electrical conductivity, and bending resistance, can be controlled.

On the first layer, the step of applying a coating composition including a conductive polymer, a binder resin and a solvent is spin coating, spray coating, dip coating, slit coating, slot die coating, It may be performed by a method such as bar coating, but is not limited thereto.

Regarding the conductive polymer and the binder resin included in the coating composition, the descriptions of the conductive polymer and the binder resin included in the second layer of the graphene laminate may be applied.

The solvent may be a solvent known in the technical field of the present invention without particular limitation, unless the conductive polymer and the binder resin included in the coating composition are modified.

According to one embodiment, the solvent may be water. According to another embodiment, as the solvent, an alcohol-based solvent, or an alcohol-based solvent and water may be mixed and used.

The sum of the components other than the solvent in the coating composition may be a solid content of the coating composition, and according to an embodiment, the content of each component in the solid content is described for the second layer of the graphene laminate This can be applied.

For example, per 100 parts by weight of the solid content, the content of the conductive polymer may be 70 parts by weight to 98 parts by weight, for example, 80 parts by weight to 96 parts by weight; The content of the binder resin may be 1 part by weight to 50 parts by weight, for example, 3 parts by weight to 35 parts by weight.

According to one embodiment, per 100 parts by weight of the coating composition, the content of the solvent may be 70 parts by weight to 99 parts by weight, for example, 80 parts by weight to 98 parts by weight, and another example, 85 to 98 parts by weight .

According to one embodiment, the step of forming a second layer including the conductive polymer and the binder resin by removing at least a portion of the solvent in the coating composition may be performed by a method of hot air drying.

For example, the third step may be performed at a temperature of 90 ° C to 160 ° C or 100 ° C to 140 ° C for 30 seconds to 120 seconds.

[Electrode materials and electronic devices]

According to one embodiment, the electrode material may include the graphene laminate.

According to another embodiment, an electrode using the electrode material may be provided. Also, an electronic device including an electrode using the electrode material may be provided.

The electrode including the electrode material may be used in devices in various electronic device fields. For example, the device may be a touch panel, an organic light emitting device, an organic thin film transistor, an organic solar cell, a secondary cell, a fuel cell, a memory device or a biosensor, but is not limited thereto.

In addition, the graphene laminate according to an embodiment of the present invention is excellent in durability and bending resistance, and thus, a small electronic device requiring a high level of flexibility, a flexible display, and a curved display ).

Hereinafter, the following examples illustrate the present invention without limiting the scope of the present invention.

[Example]

Examples 1 to 3: Preparation of graphene laminate

CVD graphene was formed on the copper substrate by using ICP as a carbon source, and transferred to a PET film to prepare a CVD graphene sheet.

0.2g of DMSO was added to the PEDOT: PSS aqueous dispersion 3.6g with a polyvinyl alcohol aqueous dispersion and an auxiliary dopant and stirred to prepare a composition for coating having the composition shown in Table 1 below. After coating the composition for coating on the first layer, the CVD graphene sheet, it was coated with # 10 bar using Mayer's bar coating equipment and dried in a 120 ° C convection oven for 1 minute to form a second layer.

Example
number Coating composition conductivity
Polymer PVA
DS 89%, MW 50,000
NV 20% Compared to conductive polymer
PVA content (based on NV) Example 1 PEDOT: PSS 0.01 20: 1 (5%) Example 2 0.02 10: 1 (10%) Example 3 0.04 5: 1 (20%) Example 4 0.10 2: 1 (50%)

Comparative Example 1

A graphene laminate was manufactured in the same manner as in Example 1, except that the second layer using the coating composition was not formed on the CVD graphene sheet.

Evaluation example: Evaluation of bending resistance of graphene laminate

The graphene laminates of Examples 1 to 4 and Comparative Example 1 were each cut to a size of 1 cm × 4 cm in length, and silver paste was separated 1 cm from both sides in the vertical direction (ie, silver paste). The interval between 2 cm) was applied as a dot and dried at 60 ° C. for 1 hour to prepare a test sample.

Next, after adjusting the bending radius of the film folding test machine (STS-RT-5AXIS manufactured by Sciencetown) to be 3R (the radius of curvature is 3 mm), after attaching the sample for testing, 120 refractions occur per minute. The speed was set to evaluate the bending resistance, and the results are shown in FIG. 1.

In FIG. 1, R ₀ is the line resistance of the test sample before refraction, R is the line resistance of the test sample after refraction one or more times, and R / R ₀ means resistance change according to the number of refractions.

Referring to FIG. 1, when the graphene laminate of Comparative Example 1 without forming a coating layer is refracted 5,000 or more times, the R / R ₀ value is 1.2 or more, that is, the line resistance is increased by 20% or more, deteriorating in terms of conductivity and durability It was confirmed. On the other hand, the graphene laminates of Examples 1 to 3 according to one embodiment have a R / R ₀ value of 1.03 or less, even if the number of refractions is increased to 100,000 or more, so the resistance change is 3% or less, so the bending resistance and durability are high. It was confirmed to be very excellent.

As described above, exemplary embodiments have been disclosed in the drawings and the specification. Although the embodiments have been described using specific terms in this specification, they are used only for the purpose of illustrating the technical spirit of the present disclosure and to limit the meaning of the terms or to limit the scope of the present disclosure described in claims. It is not done. Therefore, those skilled in the art will understand that various modifications and other equivalent embodiments are possible therefrom.

Claims (11)

materials;
A first layer disposed on the substrate and including graphene; And
It is disposed on the first layer, and includes a second layer comprising a conductive polymer and a binder resin,
The first layer is made of graphene (consist of),
The binder resin is made of polyvinyl alcohol (PVA),
The substrate is a polymer film,
The substrate and the first layer are in direct contact, the graphene laminate. According to claim 1,
The substrate is polyethylene terephthalate (polyethylene terephthalate, PET), polyethylene (polyethylene, PE), polypropylene (polypropylene, PP), polycarbonate (polycarbonate, PC), polymethyl methacrylate (poly (methyl methacrylate), PMMA), Polyimide (PI), oriented polypropylene (OPP), biaxially oriented polypropylene (BOPP), polyethylene 2,6-dicarboxyl naphthalate, PEN ), Polyethersulfone (PES), polyester (polyester, PE) or polystyrene (polystyrene, PS), a graphene laminate. According to claim 1,
The substrate is flexible, graphene laminate. According to claim 1,
The graphene is a graphene laminate including at least one selected from CVD graphene, graphene oxide (GO), and reduced graphene oxide (rGO). According to claim 1,
The graphene has a form of a film, a flake, a particle, or a paste, and the like, a graphene laminate. According to claim 1,
The conductive polymer is polyphenylene (polyphenylene), polyfluorene [poly (fluorene)], polypyrene (polypyrene), polyazulene (polyazulene), polynaphthalene (polynaphthalene),
Polypyrrole [poly (pyrrole)], polycarbazole, polyindole, polyazepine, polyaniline,
Polythiophene, poly (3,4-ethylenedioxythiophene); PEDOT], poly (p-phenylene sulfide): PPS,
Polyacetylene [poly (acetylene)], poly (p-phenylene vinylene) [poly (p-phenylene vinylene)] and derivatives thereof;
Graphene laminate, including any one selected from or any combination thereof. According to claim 1,
The first layer and the second layer are directly in contact, a graphene laminate. Forming a first layer comprising graphene on a substrate;
Applying a coating composition comprising a conductive polymer, a binder resin, and a solvent on the first layer; And
Forming a second layer including the conductive polymer and the binder resin by removing at least a portion of the solvent in the coating composition;
Including,
The first layer is made of graphene,
The binder resin is made of polyvinyl alcohol,
The substrate is a polymer film,
A method of manufacturing a graphene laminate, wherein the substrate and the first layer are in direct contact. Electrode material comprising the graphene laminate of any one of claims 1 to 7. An electronic device comprising an electrode using the electrode material of claim 9. The electronic device according to claim 10, wherein the electronic device is a touch panel, an organic light emitting device, an organic thin film transistor, an organic solar cell, a secondary cell, a fuel cell, a memory device or a biosensor.

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