KR101508144B1 - Vo2 laminate with functionalized graphene for active thermo-chromic smart window - Google Patents

Abstract

More particularly, the present invention relates to a laminate of active temperature discoloration VO ₂ (Vanadium Dioxide), more specifically, a laminate of a thermochromic layer and a heating heater, Functionalized graphene-based VO ₂ laminate.
The invention VO ₂ by using a functionalized yes pin layer by doping, artificially structural defects created in the base of the vanadium dioxide layer The light transmittance of the layered product can be improved and the user can actively control the temperature of the layered product by using a functionalized graphene-based heat generating heater.

Description

TECHNICAL FIELD [0001] The present invention relates to a functionalized graphene-based heating substrate,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a functionalized graphene-based heating substrate, and more particularly, to a heating substrate having electrodes formed on the top and / or bottom of a substrate edge or functionalized graphene layer.

It has been widely known that energy loss in buildings is the most common through window, and various methods have been tried to prevent such energy loss.

Particularly, recently, a thermochromic material, which is a characteristic in which the color of a material changes due to heat, is coated on a glass to control the energy inflow through the infrared transmittance. Such a thermochromic glass has been attracting interest in the development of a so-called 'smart window' capable of controlling light transmittance and reflectance freely.

The heat-sensitive coloring material has a characteristic that light transmittance and reflectivity vary greatly with the phase-change temperature. A representative example of the heat-sensitive coloring material is vanadium dioxide (VO ₂ ). Vanadium dioxide has metal-insulator transition (MIT) characteristics at around 340K (68 ° C). That is, vanadium dioxide exists in a metal form at a phase transition temperature of 68 ° C or higher to shield infrared rays, and when it is less than 68 ° C, it exists in an insulator form to transmit infrared rays. Accordingly, various attempts have been made to apply vanadium dioxide to smart window development.

Korean Patent Laid-Open Publication No. 2012-0127043 discloses an energy-saving window for coating a substrate with a thermochromic thin film and a transparent conductive film to improve the cooling and heating efficiency of a building. The window is formed on a substrate and on the upper surface of the substrate. Chromium thin film in which the transmittance of the vanadium dioxide is controlled. However, in the case where only vanadium dioxide is coated on the glass, the absolute value of the light transmittance is relatively low, . Further, in order to utilize the thermochromic characteristic of vanadium dioxide in a smart window, the phase transition temperature should be reduced to about room temperature, and it is necessary to control the phase transition temperature of vanadium dioxide. Accordingly, a method for improving light transmittance in a smart window and lowering the phase transition temperature of vanadium dioxide has been sought.

No. 10-2011-0080007 filed by the present applicant discloses a VO2 laminate for smart windows based on a graphene layer but there is a difficulty in controlling the grain size of the graphene, The transmittance of light is lowered by the graphene layer of the light emitting layer.

Meanwhile, the conventional smart window using the thermochromic discoloring material passively blocks or transmits light by changing the color according to the temperature of the external, so that it is inconvenient that the light is blocked or passed through regardless of the user's desired mode, .

In order to solve the above problems, the inventors of the present invention have proposed a method of forming a graphene layer by doping a graphene layer with a dopant, or by applying oxygen plasma, UV irradiation, chemical treatment, or the like to artificially generate a structural defect in the graphene layer, Functionalized graphene can improve the light transmittance and electrical conductivity by uniformly controlling the grain size and form a functionalized graphene-based substrate having electrodes and a heating portion in the functionalized graphene layer, The temperature can be controlled to actively block the light, and the present invention has been completed.

The invention functionalized for the active thermochromic VO ₂ (vanadium dioxide, Vanadium Dioxide) laminated relates to a body, and more particularly, laminated with the thermochromic layer and the heating heater, and utilized in the transfer or attaching to a smart window capable SmartWindow To provide a graphene-based VO ₂ laminate.

The functionalized graphene-based heating substrate according to the present invention comprises a substrate; A copper and / or silver electrode formed on both ends of the substrate; And a heating element between the copper and / or silver electrodes at both ends, wherein the heating element includes at least one of CNT, graphene, silver nanowire, and PEDOT / PSS.

A heating substrate according to the present invention includes a first step of forming copper and / or silver electrodes on upper and / or lower sides of the substrate at both ends of the substrate; And a second step of forming a heating element between the copper and / or silver electrodes on both ends of the substrate, between the copper and / or silver electrodes on both ends of the heating substrate, wherein the heating element is CNT, Is made by a method comprising selecting at least one of a nanowire, PEDOT / PSS.

According to another embodiment of the present invention, there is provided a method for manufacturing a touch panel, comprising: a first step of forming a functionalized graphene-based VO2 laminate for an active type temperature-sensitive color changing window on a functionalized graphene layer on a flexible substrate; A second step of depositing vanadium dioxide (VO ₂ ) on one surface of the functionalized graphene layer / functionalized graphene layer of the flexible substrate / graphene layer formed in the above step to form a vanadium dioxide layer; A third step of depositing silver nanowires on the graphene layer; And a fourth step of laminating a heating substrate on the graphene layer on which the silver nanowires are deposited in the third step, wherein the heating substrate is bonded to both ends of the substrate or the upper and / A third step of forming a copper and / or silver electrode on the first electrode; (3-2) applying PEDOT between the copper and / or silver electrodes on both ends of the substrate, and (3-3) depositing a nanowire layer on the substrate.

The first step may include a first step of forming a graphene layer on the first base material; A first step of functionalizing the graphene layer formed in the step 1-1 to form a functionalized graphene layer; Laminating the flexible substrate to form a laminate including the first substrate / functionalized graphene layer / flexible substrate; Removing the first base material from the laminate formed in the step 1-3 by using an etching method and transferring the functionalized graphene layer onto the flexible base material to form functionalized graphene layer / Steps 1-4; (1-5) forming a graphene layer on the second substrate; Laminating the functionalized graphene layer / flexible substrate formed in the step 1-4 to form a laminate including the second substrate / the graphene layer / the flexible substrate / the functionalized graphene; And a 1-7 step of removing the second base material from the laminate formed in the step 1-6 by using the etching method and simultaneously transferring the graphene layer onto the flexible base material.

According to another embodiment of the present invention, the functionalized graphene-based VO2 laminate for an active type thermochromic window includes a functionalized graphene layer having at least one or more layers: a vanadium dioxide (VO2) layer formed on one surface of the functionalized graphene layer; A flexible substrate laminated below the vanadium dioxide (VO2) layer; An electrode layer laminated on the lower portion of the flexible substrate; And a heating substrate laminated on the electrode layer.

The protective layer may further include at least one material selected from the group consisting of polymethylnathacrylate (PMMA), polyvinylidene fluoride (PVDF), polystyrene (PS) -co-PMMA-co- ), ER (electroresist), SiOx, TiOx, TiOx-Ag, ITO, FTO, or AlOx.

In addition, the functionalized graphene layer may further include a flexible substrate such as an adhesive tape to be transferred or adhered, a paste, an adhesive resin, a lightening tape, a heat-peelable tape, or a water-soluble tape.

The invention VO ₂ by using a functionalized yes pin layer by doping, artificially structural defects created in the base of the vanadium dioxide layer The light transmittance of the layered product can be improved and the user can actively control the temperature of the layered product by using a functionalized graphene-based heat generating heater.

In addition, functionalized yes pin layer is of a possible because not only can be further simplified to the relevant process, in the manufacture VO ₂ film for smart windows, since the large area upset possible active thermochromic VO ₂ film for smart windows transferred to various substrates Mass production is possible.

FIG. 1 is a schematic view of a VO ₂ stacked body for active temperature-sensitive color change smart window according to an embodiment of the present invention.
2 is a schematic view illustrating a heating substrate and a heating element based on a functionalized graphene layer according to an embodiment of the present invention.
3 is a Raman spectroscopic analysis result when gases such as NH3, N2, CH4, and H2 are doped (doped) while synthesizing graphene in a large area using CVD (Chemical Vapor Deposition)
FIG. 4 is a TEM image showing a case where a gas such as NH 3, N 2, CH 4, and H 2 is doped while doping with a large area of graphene using CVD (Chemical Vapor Deposition).
FIG. 5 is a Raman spectroscopic analysis result of inducing nitrogen substitution according to process parameters (plasma power, reactive time, gas flow) using a plasma induction apparatus (Reactive Ion Etching Plasma) and changing the doping time.

Hereinafter, embodiments of the present invention will be described in detail. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted so as to avoid obscuring the subject matter of the present invention.

The terms "about "," substantially ", etc. used to the extent that they are used herein are intended to be taken to mean an approximation of, or approximation to, the numerical values of manufacturing and material tolerances inherent in the meanings mentioned, Accurate or absolute numbers are used to help prevent unauthorized exploitation by unauthorized intruders of the referenced disclosure.

It should be noted that each layer of the VO ₂ laminate for active window type SMOOK described in this specification is only based on the attached drawings. That is, not only the case where only the layer referred to in this specification is made, but also the case where another layer intervenes or exists between the layers can be included in the scope of the present invention.

It is also to be understood that the expressions " above ", " above ", or " above " are intended to refer to the relative positional concept based on the attached drawings, Other layers or components may be intervened or present, as well as the surface of the layer referred to above (particularly, the layer having a three-dimensional shape ) May not be completely covered. Likewise, the expression " lower, " " under, " or " under " may also be understood as a relative concept of the position between a particular layer (component)

Functionalization of functionalized graphene or functionalized graphene layer herein means that the dopant is displaced by atoms of the graphene structure or artificially created defects in the graphene structure by doping.

Figure 1 is a simplified view of the VO ₂ laminate (100, VO ₂ or less active laminate) for active thermochromic smart window according to one embodiment of the present invention.

1, active VO ₂ The laminate is formed by forming functionalized graphene layers or graphene layers 102 and 103 on both sides of the flexible substrate 103 and forming a first functionalized graphene layer 102 and a first functionalized graphene layer 102 It may include fever formed based on the second pinned yes formed at the bottom of the VO _2, vanadium dioxide), the flexible substrate 103 hiteoeul;) vanadium dioxide layer (101 is formed on the top surface.

The first functionalized graphene layer 102 is formed with VO ₂ layer 101, By forming the laminate, not only the light transmittance of the VO ₂ laminate is enhanced, but also the phase transition temperature of the vanadium dioxide layer 101 can be relatively lowered.

In addition, the first functionalized graphene layer 102 may also serve to protect the vanadium dioxide layer 101 during processing. In addition, the first functionalized graphene layer 102 may serve as a seeded base during the formation of the vanadium dioxide layer 102 and may provide a smooth surface by lowering the surface roughness of the VO ₂ stack can do.

The refractive index of unfunctionalized graphene is 2.35 to 2.7, while the refractive index of functionalized graphene is 1.8, which is a relatively low value. When a laminate is formed of vanadium dioxide having a refractive index of 2.4 to 2.7 and a functionalized graphene layer, Control (when high-deflection / low-refractive-index laminated optical design) is possible.

The flexible substrate 103 is flexible and may have additional transparency. The flexible substrate P may be a tape or a thin film including a heat peelable polymer, but is not limited thereto.

For example, the flexible substrate 103 may be made of a material such as polydimethylsiloxane (PDMS), a polyurethane film, a water based adhesive, a water soluble adhesive, a vinyl acetate emulsion adhesive, a hot melt adhesive, a light curing (UV, visible, Polyvinyl alcohol (PBI), polyimide (PBI), silicone / imide, bismaleimide (BMI), modified epoxy resin, PVA (polyvinylalcohol) tape / thin film, general adhesive tape and the like.

Poly (3,4-ethylenedioxythiophene) (PEDOT) and poly (styrenesulfonate) (PSS) were coated on the upper or lower surface of the substrate, and the graphene coated with the metal nanowire was placed on the PEDOT / PSS layer A heating element is formed, and electrodes are formed at both ends or top and / or bottom of the substrate. The material of the heating substrate corresponds to both glass and flexible substrates, and as flexible substrates, it may include transparent plastic substrates such as PET, PES, PI, and the like. The minimum thickness of the plastic is 25 microns up to 5 cm. The conductive coating material can be coated by bar coating, spray coating, spin coating, or the like. In particular, when an auxiliary electrode such as graphene is further applied, it can be transferred to a target substrate using a lamination process.

In addition to forming a heating substrate by using silver nanowires after applying PEDOT / PSS to the heating substrate, the heating element may be formed by using graphene alone on a substrate, by applying PEDOT / PSS on graphene, PEDOT / PSS coated with silver nanowires, graphene coated with silver nanowires, CNT alone, coated with CNT and silver nanowires, coated with PEDOT / PSS, coated with CNT and silver nanowires , PEDOT / PSS and CNT-graphene-coated nanowires can be used. That is, at least one of CNT, graphene, silver nanowire, and PEDOT / PSS can be selected and applied to a heating substrate.

The protective layer 130 may further include a protective layer formed on the vanadium dioxide. The protective layer 130 functions to protect the VO ₂ stack 100 and the functionalized graphene layer 110 from the outside. In this case, the protective layer may be made of a material selected from the group consisting of polymethylnaphthacrylate (PMMA), polyvinylidene fluoride (PVDF), polystyrene (co-PS), co-PS, PR, photoresist, FTO, or AlOx.

1. Functionalized graphene production

Graphene for forming functionalized graphene layers or graphene layers 102 and 104 is formed by grafting a plurality of carbon atoms to each other through a covalent bond to form polycyclic aromatic molecules. The carbon atoms linked by the covalent bond form a 6-membered ring as shown in FIG. 1 as the basic repeating unit, but are not limited thereto. That is, the carbon atoms may be formed of a 5-membered ring, a 7-membered ring, or the like.

The functionalized graphene layers or graphene layers 102 and 104 may be formed of a single layer, but not limited thereto, and may be formed of a plurality of layers. For example, the functionalized graphene layer or graphene layers 102 and 104 may be formed of more than 50 layers. For multiple layers, graphene can be prepared by CVD synthesis, but after formation of single-layer graphene through CVD, graphene oxide (GO) or reduced graphene oxide graphene oxide (R-GO) may be coated to form a functionalized graphene layer.

The functionalized graphene layer or graphene layers 102 and 104 may be formed in a large area, for example, in the transverse or longitudinal direction to have a length of about 1 mm to 1000 m. On the other hand, a method of forming a functionalized graphene layer or graphene layer 102 or 104 will be described later with reference to other drawings.

In order to form the functionalized graphene layer or the graphene layer, graphene is first grown on the first substrate to form a graphene layer. The first substrate serves as a seed layer for growing the graphene, and is not limited to a specific material. For example, the first base material may be at least one selected from the group consisting of silicon, Ni, Co, Fe, Pt, Au, Al, Cr, Cu, Mg, Mn, Mo, Rh, Si, Ta, Ti, W, , Bronze, white copper, stainless steel, and Ge.

In addition, the first substrate may include a catalyst layer to facilitate the growth of the graphene. The catalyst layer is not limited to a specific material, and may be formed of the same or different material as the first base material. The thickness of the catalyst layer is not limited, and may be a thin film or a thick film.

On the other hand, a conventional chemical vapor deposition method can be used as a method of growing the graphene on the first substrate. Examples of the chemical vapor deposition include chemical vapor deposition (RTCVD), inductively coupled plasma chemical vapor deposition (CVD), low pressure chemical vapor deposition (LPCVD), atmospheric pressure chemical vapor deposition (APCVD), metal organic chemical vapor deposition ) Or chemical vapor deposition (PECVD).

For example, in order to form a graphene layer on the first base material, the first base material is placed in a furnace, and a reaction gas containing a carbon source is supplied and heat-treated at a normal pressure (300 to 2000 ° C) The pin can be grown.

Examples of the carbon source include carbon monoxide, carbon dioxide, methane, ethane, ethylene, ethanol, acetylene, propane, butane, butadiene, pentane, pentene, cyclopentadiene, hexane, cyclohexane, benzene and toluene.

On the other hand, the substrate may be a metal substrate, or may further include a metal base layer (not shown) formed between the substrate and the polymer layer. The metal substrate layer may be formed on the substrate using a conventional deposition or coating method.

In this case, the metal in the metal substrate or the metal base layer may be, for example, silicon, Ni, Co, Fe, Pt, Au, Al, Cr, Cu, Mg, Mn, Mo, Rh, Si, One or more metals or alloys selected from the group consisting of W, U, V, Zr, brass, bronze, white copper, stainless steel and Ge.

The polymer layer containing a carbon source may serve as a seed layer for graphene synthesis, and may include, for example, polymethacrylate (PMMA), polystyrene, acrylonitrile butadiene styrene (ABS) A self-assembled monolayer (SAM), and polyimide.

The graphene layer may be formed by doping a graphene layer with a dopant selected from SiHN ₄ , NH ₃ , N ₂ , XeF ₂ , and B ₂ H ₆ in addition to a hydro-carbon gas during the CVD process, The film is produced by artificially generating defects in the graphene structure by at least one of plasma treatment, UV irradiation, and wet chemical treatment.

The dopant used for functionalized graphene fabrication may include, but is not limited to, an organic dopant, an inorganic dopant, or a combination thereof.

When the dopant vapor is used in the doping process, the dopant vapor may be formed in the container containing the doping solution by a heating device for vaporizing the doping solution. When a doping solution is used in the doping process, a container containing the doping solution may be provided with a height adjusting device for adjusting the gap between the graphene film and the solution.

The characteristics of the doped graphene film formed by the doping process can be controlled by varying the dopant and / or the doping time in the doping process. For example, the refractive index and transparency of the doped and / or doped graphene films can be controlled by varying the doping time and / or the doping time.

It is possible to functionalize graphene by artificially forming defects on the graphene surface by treating the surface of the graphene with an oxygen plasma, that is, by generating structural defects in the graphene, so that the electrical characteristics, light transmittance And refractive index.

Structural defects of graphene are characterized by the heating of graphene, contact with gases chemically reacting with graphene, UV irradiation, application of ultrasonic waves, or contact with oxygen plasma, Not only the electrical characteristics of the fin are controlled, but also the crystal growth can be controlled at the time of graphen generation, so that the grain size can be controlled to be uniform.

To generate defects in the graphene layer, an oxygen plasma (plasma finish GmbH V6-G) was produced at a plasma power of 5 to 500 W, an oxygen flow rate of 1 to 100 sccm, and a pressure of 100 Pa to bring the graphene layer and the oxygen plasma into contact.

And UV irradiation can control functional groups bound to graphene edge and organic matter remaining on graphene surface. The UV wavelength used is Hg lamp (LH-arc, Lichtzen, with an output of 20mWcm- ² , with a majority of the emitted light at a wavelength of 254nm and approximately 10% Do not exceed 30 minutes.

Finally, the wet chemical treatment can induce defects on the graphene surface or edge using chemicals consisting of hydrochloric acid, nitric acid, sulfuric acid, hydrogen peroxide, hydrofluoric acid, and combinations thereof. The chemical (liquid) The defect rate can be controlled by increasing the degree.

2. Flexibility of functionalized graphenes Transcription to substrate

A method of transferring the graphene layer can be either a direct transfer method or an indirect transfer method, and it is possible to use a known roll-to-roll process.

Functionalized graphene layers or graphene layers 102 and 104 are formed on the upper portion and the lower portion of the flexible substrate 103, respectively. The first functionalized graphene layer 102 serves as a base on which titanium dioxide of the thermosensitive unit 105 is formed and the second graphene layer 104 is transparent and serves as an electrode. .

As the electrode, in addition to graphene, ITO, FTO, or silver nanowire, silver nanomesh, PEDOT: PSS, and combinations thereof may be used.

Specifically, the first base material on which the functionalized graphene layer 102 is formed is laminated by passing a plurality of roller portions facing each other together with the flexible substrate 103, and then another roller portion (for example, a transfer roller) The first base material is removed by etching and the functionalized graphene layer 102 is transferred to the flexible substrate 103. Here, the above-mentioned etching method means using an etching solution capable of selectively etching the first base material, and can be selected corresponding to the type of the first base material. Examples of the etching solution include hydrogen fluoride (HF), buffered oxide etch (BOE), ferric chloride (FeCl ₃ ) solution, ferric nitrate (Fe (NO ₃ ) ₃ ) solution, sulfuric acid and water, But is not limited thereto.

That is, the first substrate - the first functionalized graphene layer 102 - the flexible substrate 103 is passed through the transfer roller, but the etching solution for etching only the first substrate during passing is constructed as a stationary structure, It is possible for the graphene layer 102 to be transferred onto the flexible substrate 103 while being removed by the etching solution.

The second graphene layer 104 laminated on the lower portion of the flexible substrate 103 is transferred to the flexible substrate 103 in a similar manner as the first functionalized graphene layer 102. In the case of the second graphene layer 104 laminated on the lower side of the flexible substrate 103, the first functionalized graphene layer 102 transferred on the upper side of the flexible substrate 103 is transferred to the second The graphenes 104 are laminated by passing a plurality of roller portions facing each other and then passed through another roller portion (for example, a transfer roller) to form the second graphenes 104, The second graphene layer 104 can be transferred to the flexible substrate 103 while being removed by an etching method.

That is, the first base-second graphene layer 104, the flexible substrate 103, and the first functionalized graphene layer 102 are passed through the transfer roller, The first base material is removed by the etching solution, and at the same time, the second graphene layer 104 can be transferred onto the flexible substrate 103.

Of course, it is described herein that the first functionalized graphene 102 positioned on the upper side of the flexible substrate is transferred to the flexible substrate, and then the second graphene 104 positioned below is transferred to the flexible substrate. However, It is obvious to those skilled in the art that the order in which the functionalized graphene layers 102 and 104 deposited on the top and bottom of the substrate are transferred to the substrate is irrelevant.

Example 1:

1) PET substrate preparation

A polyethylene terephthalate substrate was prepared.

2) Functionalized graphene film formation

A rolled foil of Cu was placed in the quartz tube and then heated to 1,000 DEG C under atmospheric pressure. (CH 4: H 2: He = 50: 15: 25-121000 sccm) containing a carbon source was supplied to grow the graphene on the Cu foil. Thereafter, He was allowed to flow in a short time, And cooled to room temperature to obtain a graphene film grown on the Cu foil.

① Graphene functionalization through nitrogen substitution during CVD process

FIGS. 3 and 4 are experimental results when a gas such as NH 3, N 2, CH 4, and H 2 is doped (doped) while synthesizing graphene in a large area using CVD (Chemical Vapor Deposition) .

Raman spectroscopy analysis reveals differences in electron structure and binding energy, such as when the nitrogen atom is replaced with a carbon atom of the graphene (graphitic) and when it is doped to the edge of the broken structure (pyridinic). Analysis of Raman Peak reveals that the D and G 'intensity values of the graph are increased by doping from the pristine graphene to the graphene of the N-type electron structure, and the 2D intensity reduction and the FWHM (full width half maximum) value increase Respectively.

(2) Graphene functionalization through plasma-assisted CVD graphene and graphite (HOPG) nitrogen substitution

CVD graphene (PDMS transfer method) and HOPG (Highly Ordered Pyrolytic Graphite) graphene were fabricated on SiO ₂ / Si substrate to induce nitrogen substitution of graphene. 5, the prepared graphene samples were subjected to nitrogen substitution according to process parameters (plasma power, reactive time, and gas flow) using Reactive Ion Etching Plasma (RIE Plasma) and the doping time was changed. The Raman spectroscopic analysis shown in FIG. 5 confirms that the N-type electron structure is doped with increasing time. However, at 10 seconds, the 2D peak disappears and the graphene is damaged due to the influence of plasma for a long time. The G 'peak, which appears next to G peak as it is doped, represents the graphene surface and edge defects through the plasma process.

3) Functionalized graphene transcription on PET substrate

Then, a thermal release tape was adhered to the functionalized graphene film formed on the Cu foil through an adhesive roller. Next, the Cu foil-graphene film-heat-peelable tape laminate was impregnated with a 0.5 M FeCl 3 etching aqueous solution, and the Cu foil was etched by electrochemical reaction. Thereafter, the functionalized graphene film is contacted with the PET substrate through a transfer roller, heat is applied while rolling, and the functionalized graphene film is detached from the thermally peelable tape, thereby forming the functionalized graphene film on the PET substrate Transcribe. The same method is repeated to transfer functionalized graphenes to both sides of the PET substrate.

3. Manufacture of heating substrate

A heating substrate is schematically shown in Fig. 2, in which PEDOT is applied to the top or bottom of the substrate, the coated PEDOT layer is coated with metal nanowires to form a heating element, and the top and / Or an electrode is formed on the bottom. The heat-generating substrate can be made of glass or flexible substrate, and a transparent plastic substrate such as PET, PES, PI or the like can be included in order to impart heat to the flexible substrate. The minimum thickness of the plastic is 25 microns up to 5 cm. The conductive transparent electrode ink material (PEDOT: PSS: PSS-Ag hybrid ink) can be coated by bar coating, spray coating or spin coating. . Particularly, when an auxiliary electrode such as graphene is additionally applied to the upper or lower surface of the ink material, the graphene can be transferred to the target substrate using a lamination process (same as VO2 / functionalized graphene transfer method).

The electrode is made of silver, copper, or an alloy thereof.

At this time, the nanowire 201 may be formed on the second functionalized graphene layer to which PEDOT is applied as shown in FIG. 2, between the substrate and the graphene layer, or between both the substrate and the graphene layer, .

The metal nanowire may be a metal, a metal alloy, a plated metal, or a metal oxide. The metal nanowires may include any one or more selected from the group consisting of silver nanowires, gold nanowires, copper nanowires, nickel nanowires, gold plated silver nanowires, platinum nanowires, and palladium nanowires. have.

In order to form the nanowire, the metal nanowire may be formed of an ink composition. The ink composition may be prepared by mixing and stirring an urethane water dispersion, a dispersion stabilizer, ultrapure water and an alcohol, and then ultrasonically dispersing the mixture with an ultrasound disperser.

The ink composition may be based on the desired concentration of nanowires and the coating method may be selected from the group consisting of spin coating, gravure coating, slit coating, bar coating, spray coating, vacuum filtration coating, electrophoretic deposition, casting, inkjet printing, A printing method can be used.

Example 2:

1) Manufacture of nanowires

A solution was prepared by dissolving 2 g of EMIMEtOSO3 (1-Ethyl-3-methylimidazolium ethylsulfate, product of BASF) in 30.926 g of ethylene glycol (manufactured by Daikin Kinko Co., Ltd.). 0.79 g of silver nitrate (AgNO3, manufactured by Daqing Kagaku Co., Ltd.) was dissolved in 10 g of ethylene glycol to prepare a solution. The two solutions were mixed in a 250 ml three-necked flask and stirred at 25 ° C for 10 minutes. The mixed solution was stirred at 160 캜 for 3 hours through a magnetic bar to obtain a gray nanowire. After completion of the reaction, the reaction mixture was cooled to room temperature, and the reaction mixture was filtered through a membrane filter (1-3 μm, Advantec). The filtered material was dried in a 100 < 0 > C vacuum oven for one day and weighed.

The filter material was diluted about 10 times with acetone and ethanol and centrifuged at 2000 rpm for about 10 minutes using a centrifuge (Continent R, Hanil Scientific Co., Ltd.) to collect the wire-like particles, The resultant was dried again in a vacuum oven at about 40 ° C for one day, and the weight of the sample was measured. The generated silver nanowires were 70 nm in diameter, 12 μm in length, and the nanowire formation rate was 82 wt%.

2) Deposition of the nanowire layer

The silver nanowires were agitated for about 10 minutes with a urethane aqueous dispersion (NeoRez R986, DSM), a dispersion stabilizer (Dynol 604, air product), ultra pure water and alcohol, and then homodispersed (TK HOMODISPER, The ink composition was prepared by ultrasonic dispersion at 5 MJ for 5 minutes using an ultrasonic disperser (VCX-750, Sonics). The ink composition was deposited on the second functionalized graphene composite by a spin coating method. The coating conditions were spin-coated at a speed of 500 rpm for 60 seconds, then dried at 50 DEG C for 90 seconds and at 180 DEG C for 90 seconds.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit of the invention as set forth in the appended claims. The present invention can be variously modified and changed by those skilled in the art, and it is also within the scope of the present invention.

101: VO2 layer 102: first functionalized graphene layer
103: Flexible substrate 104: Second graphene layer
105: Thermal sensation discoloration unit 106: Heat generating unit
201: silver nanowire 202: graphene layer

Claims (4)

Board;
A heating element comprising a PEDOT / PSS layer applied on top of the substrate and a functionalized graphene layer overlying the PEDOT / PSS layer and coated with silver nanowires;
And at least one electrode selected from copper and silver at both ends of the substrate. delete delete delete

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