KR20140086325A - multi-functional flexible laminate for smart window - Google Patents

Abstract

The present invention relates to a multi-functional flexible laminated film for a smart window whereby thermo-chromic and electro-chromic laminates, or thermo-chromic and polymer dispersed liquid crystal (PDLC) laminates are formed on both surfaces of a flexible substrate, such that light is blocked or transmitted in responses to temperature and/or electric; and a method of fabricating the same. Functional graphene is used as a base of a temperature sensing material such that the phase transition temperature is relatively decreased. In addition, a size of a crystal structure is uniformly controlled such that surface roughness is reduced, thereby allowing the multi-functional flexible laminated film have a smooth surface. Since the functional graphene has superior electric conductivity, the response speed of the electro-chromic or PDLC electrode layer is improved.

Description

Multi-functional flexible laminate film for smart windows [0002]

The present invention relates to a multi-functional smart window laminate having thermochromic laminates, electrochromic laminates, thermochromic laminates and polymer dispersed liquid crystals (PDLC) formed on both sides of a flexible substrate, And a production method thereof.

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 of changing the color of a material by 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 thermochromic discoloration material is characterized in that light transmittance and reflectivity vary greatly based on the phase change temperature. Typical examples of the thermochromic discoloration material include vanadium dioxide (VO ₂ ). Vanadium dioxide has metal-insulator transition (MIT) characteristics at around 340K (68 ° C). That is, the 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.

Accordingly, 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 a heating and cooling efficiency of a building. The window is formed on a substrate and on a surface of the substrate. And a thermochromic thin film having a controlled transmittance. However, in the case of coating only vanadium dioxide on glass, the absolute value of the light transmittance is relatively low, and thus it is limited to apply to 'smart window'. Further, in order to utilize the thermal discoloration 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 VO ₂ laminate for smart windows based on a graphene layer but there is a difficulty in controlling the grain size of the graphene, The size of the graphene layer decreases the transmittance of light.

In addition, a smart window using electrochromic materials using a phenomenon in which a color change occurs due to a redox reaction due to charge transfer when a voltage is applied along with a smart window using a thermochromic material is increasing. Electrochromic materials are expected to be widely used in various flat panel displays including smart windows because they are excellent in reflectance, excellent in flexibility and portability, and light in weight because they do not require an external light source. For example, smart window, smart sunroof, filter, rear-view mirrors and displays using electrochromic principles have recently been introduced.

ITO (Indium Tin Oxide) has been mainly used as the electrode material of the device using such electrochromism. However, the ITO electrode is manufactured under process conditions suitable for a glass substrate, and when the ITO electrode is sputtered on a plastic substrate, the flexibility of the electrode layer is insufficient. In addition, ITO electrodes are expensive to manufacture, and indium (In), which constitutes ITO, is dominated by China, and the supply amount is not sufficient. For this reason, Japan is developing a technology to replace ITO transparent electrodes as a national project.

As a means for replacing the ITO transparent electrode, a transparent electrode using graphene has been developed. On the other hand, Korean Patent Laid-Open Publication No. 2010-0091664 discloses an electrochromic device using graphene and a manufacturing method thereof. The patent does not use graphene alone as an electrode but forms a graphene layer on an electrode made of ITO or the like. Since it still uses ITO, it is not free from the above-mentioned problems. At present, graphene-based electrode elements are difficult to efficiently synthesize or transfer graphene, and have low electrical conductivity and thus can not secure the quality required for actual production.

Meanwhile, smart windows using polymer dispersed liquid crystals (PDLC) are being developed in addition to smart windows using thermochromic materials and electrochromic materials.

When a PDLC is applied to a smart window, fine liquid crystal droplets are formed in a matrix of a polymer material, and in response to a voltage applied from the outside, when the voltage is applied, light is transmitted through the smart window The liquid crystal is irregularly arranged in a state in which no voltage is applied and scattered light because the liquid crystal is not arranged according to the traveling direction of the light passing through the smart window.

Korean Patent Laid-Open Publication No. 2011-0062215 discloses a method of producing a PDLC light modulator. In addition, although a smart window using PDLC is disclosed in Korean Laid-Open Patent Publication Nos. 2004-0045543 and 2012-0040541, it is possible to use ITO, IZO (In-ZnO), GZO (Ga-ZnO), AZO (Al-ZnO), AgZO (Al-Ga ZnO), IGZO (In-Ga ZnO), IrOx, RuOx, RuOx / ITO, Ni / IrOx / Au and Ni / IrOx / Au / ITO. As described in the electrochromic material, when sputtering is performed on a plastic substrate, the flexibility of the electrode layer is not only insufficient, but also the manufacturing cost is high.

In contrast to a smart window having only one function in the past, the present inventors have found that, in order to pass or block light in response to temperature and / or electricity, a thermochromic material, an electrochromic material, The present inventors have accomplished a flexible multi-functional smart window laminate by forming them on both sides. In particular, as described above, in order to prevent deterioration of light transmittance by an irregular sized graphene layer and to improve the conductivity of graphene, By applying doping with dopant, or by applying oxygen plasma, UV irradiation, chemical treatment or the like, artificial graphene layer is formed with structural defects to impart functionality to the graphene layer, and functionalized graphene uniformly adjusts the grain size And the light transmittance can be improved. Thus, the present invention has been completed.

The present invention provides a multifunctional smart window laminate for passing or blocking light in response to temperature and / or electricity by forming a thermosensitive coloring material, an electrochromic material, or a thermochromic material and PDLC on both sides of a flexible substrate, respectively I want to.

In addition, the present invention intends to improve the light transmittance of graphene by adding functionalities to the graphene by pretreating the graphene by doping, defect formation, or the like.

A flexible smart window multi-functional laminate according to an embodiment of the present invention includes a first step of forming a functionalized graphene layer on a flexible substrate, and a graphene layer on a bottom of the flexible substrate; A second step of depositing vanadium dioxide (VO ₂ ) on the functionalized graphene layer formed in the above step to form a vanadium dioxide layer, and depositing an electrochromic material and an electrode layer on the lower graphene layer surface to form an electrochromic layer and an electrode layer ≪ / RTI >

The flexible smart window multi-functional laminate according to an embodiment of the present invention includes a flexible substrate having at least one or more layers on the top and having a functionalized graphene layer and a first electrode layer formed on the bottom; A vanadium dioxide (VO2) layer formed on one surface of the functionalized graphene layer; An electrochromic layer laminated on the first electrode layer; And a second electrode layer laminated on the electrochromic layer.

According to another embodiment of the present invention, a flexible smart window multi-functional laminate includes a first step of forming a first functionalized graphene layer on a first flexible substrate and a second graphene layer on a bottom;

A second step of depositing vanadium dioxide (VO ₂ ) on one surface of the first functionalized graphene layer / flexible substrate / second functionalized graphene layer of the first functionalized graphene layer formed in the above step to form a vanadium dioxide layer; A third step of forming a third graphene layer on one side of the second flexible substrate; A laminate of a vanadium dioxide layer / a first functionalized graphene layer / a flexible substrate / a second graphene layer laminate formed in the second step, a PDLC layer, a third graphene layer / a second flexible substrate laminate formed in the third step And a fourth step of producing a laminate comprising a vanadium dioxide layer / a first functionalized graphene layer / a flexible substrate / a second graphene layer / a PDLC layer / a third graphene layer / a second flexible substrate layer do.

The flexible smart window multi-functional laminate according to an embodiment of the present invention includes a first flexible substrate having at least one layer on top and having a first functionalized graphene layer and a first electrode layer on the bottom; A vanadium dioxide (VO2) layer formed on one side of the first functionalized graphene layer; A PDLC layer stacked on the other surface of the electrode layer; A second electrode layer laminated on the PDLC layer; And a second flexible substrate on which the second electrode layer is laminated.

The flexible multi-functional smart window laminate according to the present invention forms a thermosensitive material and an electrochromic material or a PDLC on both sides of a flexible substrate to block or transmit light in response to temperature and / or electricity.

By using the functionalized graphene as the base of the thermosensitive material, the phase transition temperature of the thermosensitive material can be relatively lowered and the size of the crystal structure can be uniformly controlled, so that the surface roughness can be lowered to have a smooth surface, The electrical conductivity is excellent, so the response speed is improved by electrochromic or PDLC electrodes.

Further, the functionalized Yes Yes pin layer or pinned layer, so the transfer is possible at a variety of substrates VO ₂ for the smart window It is possible to simplify the related processes at the time of manufacturing the electrochromic laminates and PDLC laminates including the laminate, the electrode, and the large area, so that it is possible to mass-produce a flexible multi-functional smart window laminate.

1 is a cross-sectional view schematically illustrating a flexible multi-functional laminate according to an embodiment of the present invention.
2 is a cross-sectional view schematically illustrating a flexible multi-functional laminate according to another 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.

The functionalized graphene-based VO ₂ for smart windows described herein It is to be noted that each layer of the laminate, the electrochromic laminates, and the PDLC laminate is only presented 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 " in this specification are intended to refer to the relative positional concept relative to the attached drawings, (Particularly surfaces having a three-dimensional shape), although other layers or components may be present or present, as well as those present in the upper layer in relation to the layer referred to, It is possible to include the case where the cover is not 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.

First, a flexible multi-functional laminate in which a thermosensitive material and an electrochromic material are combined according to an embodiment of the present invention will be described with reference to FIG. 1 is a cross-sectional view schematically illustrating a flexible multi-functional laminate according to an embodiment of the present invention.

1. Functionalized Grapina  Produce

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, first, And a graphene layer is formed. 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. Functionalized Grapina  Transcription for flexible substrates

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.

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.

A functionalized graphene layer 102 and a graphene layer 104 are formed on the flexible substrate 103. The functionalized graphene layer 102 serves as a base on which titanium dioxide of the thermosensitive unit 109 is formed. The graphene layer 104 is transparent and serves as an electrode. The electrode is closely related to the response speed of the electrochromic device have.

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.

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 graphene layer 104 laminated on the lower portion of the flexible substrate 103 is transferred to the flexible substrate 103 in a manner similar to the functionalized graphene layer 102. In the case of the graphene layer 104 laminated on the lower portion of the flexible substrate 103, the first functionalized graphene layer 102 transferred to the upper portion of the flexible substrate is transferred to the graphene 104 ) Is passed through a plurality of roller portions facing each other, and the first base material on which the graphene 104 is formed is passed through another roller portion (for example, a transfer roller) to remove the first base material by using the etching method The graphene layer 104 can be transferred to the flexible substrate 103 at the same time.

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

Of course, in the above description, the first functionalized graphene 102 located on the upper portion of the flexible substrate is transferred to the flexible substrate, and then the graphen 104 positioned at the lower portion is transferred to the flexible substrate. However, And the order in which the functionalized graphene layers or graphene layers 102 and 104 stacked on the bottom are transferred to the substrate are irrelevant to those skilled in the art.

The graphene layer 104 may be formed of ITO, FTO, or silver nanowire, silver nanomesh, PEDOT: PSS, or a combination thereof, in addition to graphene as an electrode.

3. Warmth  Material and electrochromic material lamination

The functionalized graphene layer 102 functions as a warming unit 109 together with the vanadium dioxide layer 101 to improve the light transmittance of the warming unit as well as to increase the phase transition temperature of the vanadium dioxide layer 101 relatively Can be lowered.

The functionalized graphene layer 102 may also serve to protect the vanadium dioxide layer 101 during processing. In addition, the functionalized graphene layer 102 can function as a seed base in the shape of the vanadium dioxide layer 101 and function to provide a smooth surface by lowering the surface roughness of the temperature sensing unit 109 .

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 vanadium dioxide layer 101 is formed on the upper surface of the functionalized graphene layer 102 and includes vanadium dioxide (VO ₂ ). The vanadium dioxide has a metal-insulator transition (MIT) characteristic from an insulator to a metal at about 340K (68 DEG C). Accordingly, the vanadium dioxide is present in a metal form at a phase transition temperature of 68 캜 or higher and shields infrared rays, and when it is less than 68 캜, it is present in an insulator form to transmit infrared rays.

Since the vanadium dioxide corresponds to a material having a temperature sensitive property, the shielding function of the smart window can be controlled by using the MIT characteristic and the temperature sensitive characteristic of the vanadium dioxide.

The vanadium dioxide layer 101 may be formed on the upper surface of the functionalized graphene layer 102 by thermal deposition, CVD (chemical vapor deposition), sputtering, -gel), but the present invention is not limited thereto.

Titanium dioxide (TiO ₂ ), zinc oxide (ZnO) or tungsten oxide (WO ₃ ) may be used as the electrochromic material, respectively.

The electrolyte layer 106 may be composed of a solution in which an electrolyte salt such as a lithium salt, a potassium salt, a sodium salt, or an ammonium salt is dissolved in an aqueous solvent or a non-aqueous organic solvent. These salts may be used by mixing one or more of them. Preferably, the salt is a lithium salt. Examples of the non-aqueous solvent include carbonates, alcohols, ethers, and the like. Specific examples of the non-aqueous solvent include ionic organic solvents such as methylene carbonate, ethylene carbonate, propylene carbonate, ethylmethyl carbonate,? -Butyrolactone, ethylene glycol, polyethylene glycol and imidazolium- roneun tantalum oxide _{(Ta 2 O 5), Li} 3 PO 4, LiNBO 3, Li 3 + x PO 4 - x N x (LiPON), LiVO 3 / SiO 2 / Li 4 SiO 4 -Li 3 VO 4 (LVSO ) Layer is used.

The electrolyte may be deposited on the surface to be formed by injecting an electrolyte between the substrates and then sealing or, in the case of a solid electrolyte, by a sputtering method.

WO ₃ (105), Ta ₂ O ₅ (106), and NiO (107) thin films are deposited on the respective graphene layers. At this time, a sputtering method can be used to form a thin film. At this time, the working pressure is preferably 0.7 Pa, and the oxygen partial pressure is 0% to 10%. More preferably is, WO ₃ The oxygen partial pressure during deposition is 2 ~ 3%, the oxygen partial pressure during Ta ₂ O ₅ deposition is 0 ~ 5%, and the oxygen partial pressure during NiO deposition is 10%.

In addition, an electrode layer is formed of the ITO layer for electrodes (108, 104) or the FTO layer in the lower portion (or upper portion) of the electrochromic layer by a sputtering method. At this time, graphene, Ag nanowire, Ag nano mesh, PEDOT: PSS and a combination thereof can be substituted for the electrochromic layer on the wet process basis instead of the dry process.

4. PDLC  Include Smart For Windows The laminate  Produce

Another embodiment of the present invention, a flexible multi-functional laminate for smart windows, including PDLC, is schematically illustrated in Fig.

PDLC includes liquid crystals, dyes, oligomers, monomers and photoinitiators. Preferred examples of photoinitiators include diphenyl (2,4,6-trimethylbenzoyl) -phosphine oxide (MAPO-based photoinitiator), phenylbis (Trimethylbenzoyl) -phosphine oxide (BAPO-based photoinitiator), bis (eta 5-2,4-cyclopentadien-1-yl) bis [2,6-difluoro- 1-phenyl) titanium (Metallocene photoinitiator).

The liquid crystal, the dye, the oligomer, the monomer and the like can be selected from the conventional ones used in the conventional liquid crystal dispersion composition for general PDLC type light control.

Typically, the liquid crystal used in the PDLC is 4-n-propyl-4'-cyanobiphenyl, 4-n-butyl-4'-cyanobiphenyl, 4- cyanobiphenyl, 4-n-octyloxy-4'-cyanobiphenyl, 4-trans-propylcyclohexylcyanobenzene, 4-trans-butylcyclohexylcyanobenzene, 4-trans Trans-hexylcyclohexylcyanobenzene, 4-trans-heptylcyclohexylcyanobenzene, 4-cyanoheptyl-4'-trans-propylcyclohexylcarboxylate, 4-cyan 4-trans-butyl cyclohexyl carboxylate, 4-cyanoheptyl-4'-trans-pentyl cyclohexyl carboxylate, 4-cyanophenyl-t-butyl benzoate, 4-cyano-phenyl-4'-trans-pentylcyclohexylbenzoate, 4-trans-propylcyclohexylcyclohexylbenzoate, Hexyl-4'-ethylbiphenyl, 4-trans-pentylcyclo 4-ethylphenyl-4'-trans-pentylcyclohexylbenzoate, 4-ethoxyphenyl-4- Phenyl-4'-trans-pentylcyclohexylbenzoate, and 4-fluoro-phenyl-4'-trans-pentylcyclohexylbenzoate can be used singly or in combination.

The dye may be one or more kinds selected from azo dyes, anthraquinone dyes, phenylene dyes, melocyanine dyes, azomethine dyes, phthalo perylene dyes, indigo dyes, azulene dyes, dioxazine dyes and polythiophene dyes Can be selected and combined. At this time, the dye may be a combination of two or more dyes depending on the color intended to be expressed in the light adjuster, or may be included alone. Azo dyes, anthraquinone dyes and perylene dyes are preferable, and azo dyes and anthraquinone dyes are particularly preferable. As the azo dye, any of a monoazo dye, a bisazo dye, a trisazo dye, a tetrakisazo dye, a pentakisazo dye and the like is preferable, and a monoazo dye, a bisazo dye and a trisazo dye are preferable. The azo dye usually includes a ring structure, and examples of the ring structure include a carbon ring (benzene ring, naphthalene ring and the like) and a heterocyclic ring (a quinoline ring, a pyridine ring, a thiazole ring, a benzothiazole ring, A benzooxazole ring, an imidazole ring, a benzimidazole ring, a pyrimidine ring, etc.). The anthraquinone dye preferably contains an oxygen atom, a sulfur atom or a nitrogen atom as a substituent, and it preferably contains, for example, alkoxy, aryloxy, alkylthio, arylthio, alkylamino or arylamino group. The substitution number of the substituent may be any number, but it may be di-, tri-, tetrakis-

Is particularly preferred, and particularly preferably is di-substituted or tri-substituted. The substitution position of the substituent may be any position, but is preferably 1,4-position di-substituted, 1,5-position di-substituted, 1,4,5-position tri-substituted, 1,2,5-position tri-substituted, 1,2,4,5-tetra-substituted, 1,2,5,6-tetra-substituted structure.

As the composition for forming the polymer material matrix, the oligomer may be selected from the group consisting of an achiral 3-mercaptopropionate, an alkyl thiocate, an alkyl thiol, a urethane oligomer having at least one allyl group, a urethane acrylate oligomer, a fliester acrylate oligomer, Epoxy acrylate oligomers may be used alone or in combination of two or more. The monomers can be used in combination in monofunctional or multifunctional acrylate monomers and vinyl ether monomers. For example, it is possible to use acrylic acid esters such as hydroxyethyl acrylate (HEA), hydroxyethyl methacrylate (HEMA), 1,6-hexanediol acrylate (HDDA), tripropylene glycol diacrylate (TPGDA) and trimethylolpropane triacryl (TMPTA), butanediol monovinyl ether, 1,4-cyclohexanedimethanol monovinyl ether, and triethylene glycol divinyl ether can be used singly or in combination of two or more.

Here, as an additive, an antioxidant, an ultraviolet absorber, a surfactant, a defoaming agent and the like may be further included if necessary.

The thermosensitive material unit 208 is the same in construction and manufacturing method as the flexible multi-functional laminate for smart window by the above-described laminate of the thermosensitive material and the electrochromic material.

The second graphene layer 204 formed under the first flexible substrate 203 is also the same as described above.

The third graphene layer 206 is formed on the first base material and the third graphene layer 206 is formed by the roll-to-roll method while the first base material is removed by etching as described in the laminate of the thermosensitive material and the electrochromic material And transferred to the second flexible substrate 207.

The PDLC layer may be introduced and laminated with a thermochromic material 201 - a first functionalized graphene layer 202 - a first flexible substrate 203 - a second graphene layer 204, May be introduced into the roller portion together with the flexible base material 207-third graphene layer 206 and stacked.

Finally, a flexible multi-functional laminate for SmartWindows comprising PLDCs is produced by laminating the two bodies by passing the PDLC layer-laminated body and the PDLC-unbonded body together through a plurality of roller portions facing each other.

The second and third graphene layers 204 and 206 may be formed of ITO, FTO or silver nanowire, silver nanomesh, PEDOT: PSS, and combinations thereof, in addition to graphene.

1 according to an embodiment of the present invention may further include a protective layer (not shown) formed on the vanadium dioxide layer 120 and / or under the ITO electrode. In addition, the flexible smart window multi-functional laminate shown in FIG. 2 may further include a protective layer (not shown) formed on the vanadium dioxide layer 120. The protective layer functions to protect the vanadium dioxide layer 120. For example, the protective layer protects the vanadium dioxide layer 120, and may include, for example, polymethyl methacrylate (PMMA), polystyrene (co) ), SiOx, TiOx, TiOx-Ag, ITO, FTO, or AlOx.

Production Example 1. Manufacture of laminate for smart window consisting of VO2 / functionalized graphene / PET / functionalized graphene / WO3 / Ta2O5 / NiO

 1) PET substrate preparation

A polyethylene terephthalate substrate was prepared.

 2) Functionalized graphene film formation

 A rolled foil of Cu was placed in a quartz tube,

Lt; / RTI > (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.

4) WO ₃ thin film deposition

An electrochromic material, WO _3, was deposited on the functionalized graphene / PET / functionalized graphene film complex by sputtering. The sputtering conditions were RF Power 250 W, O ₂ partial pressure 2%, and pressure 0.7 Pa. This process yielded functionalized graphene / PET / functionalized graphene / WO ₃ composites.

5) Ta ₂ O ₅ , NiO ₂ thin film deposition

Ta ₂ O ₅ and NiO ₂ were deposited on the other functionalized graphene / PET / functionalized graphene / WO 3 composite that had been processed to the above step by sputtering. At this time, the sputtering conditions were RF Power 150W, O2 partial pressure 10%, and pressure 0.7Pa. Through this process, a functionalized graphene / PET / functionalized graphene / WO ₃ / Ta ₂ O ₅ / NiO ₂ laminate was obtained.

6) VO2 thin film deposition

The VO ₂ was deposited by sputtering on another functionalized graphene / PET / functionalized graphene WO ₃ / Ta ₂ O ₅ / NiO ₂ composite that had been processed to the above step. At this time, the sputtering conditions were RF Power 150 W, O ₂ partial pressure 10%, and pressure 0.7 Pa. Through this process, a VO ₂ / functionalized graphene / PET / graphene / WO ₃ / Ta ₂ O ₅ / NiO ₂ laminate was obtained.

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: Functionalized graphene layer
103: Flexible substrate 104: ITO, FTO, graphene layer or silver nano wire
105: WO ₃ layer 106: Ta ₂ O ₅ layer (electrolyte layer)
107: NiO ₂ layer 108: ITO, FTO, graphene layer or silver nano wire
109: thermal deterioration unit 110: electrochromic unit
201: VO ₂ layer 202: first functionalized graphene layer
203: first flexible substrate 204: second graphene layer (or first electrode layer)
205: PDLC layer 206: third graphene layer (or second electrode layer)
207: second flexible substrate 208: thermochromic discoloration unit
209: PDLC unit

Claims (17)

A first step of forming a functionalized graphene layer on the upper portion of the flexible substrate and a graphene layer on the lower portion;
A second step of depositing vanadium dioxide (VO ₂ ) on the functionalized graphene layer formed in the above step to form a vanadium dioxide layer, and depositing an electrochromic material and an electrode layer on the lower graphene layer surface to form an electrochromic layer and an electrode layer And a flexible smart window.
[2] The method of claim 1, wherein the first step comprises: a 1-1 step of forming a graphene layer on the first substrate;
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 a second substrate / a graphene layer / a flexible substrate / functionalized graphene;
And removing the second base material from the laminate formed in the step 1-6 by using an etching method and transferring the graphene layer onto the flexible base material, A method for producing a multifunctional laminate.
The electrochromic device according to claim 1 or 2, wherein the electrochromic material is titanium dioxide (TiO ₂ ), zinc oxide (ZnO) or tungsten oxide (WO ₃ ), and the electrode layer comprises graphene, ITO, FTO, silver nanowire, Silver nano-mesh, PEDOT: PSS, or a combination thereof.
The method of claim 1 or 2, wherein the electrochromic layer comprises tungsten oxide (WO ₃ ) / electrolyte layer / NiO 2.
The lithium _secondary battery according to claim 4, wherein the electrolyte layer is a Ta ₂ O ₅ layer, Li ₃ PO ₄ , LiNBO ₃ , Li _{3 + x} PO _{4 - x} N _x (LiPON), LiVO ₃ / SiO ₂ / Li ₄ SiO ₄ -Li ₃ > VO < ₄ > (LVSO) layer.
A flexible substrate having a functionalized graphene layer having at least one or more layers on its upper portion and a first electrode layer formed on its lower portion;
A vanadium dioxide (VO2) layer formed on one surface of the functionalized graphene layer;
An electrochromic layer laminated on the first electrode layer;
And a second electrode layer laminated on the electrochromic layer.
The electrochromic device according to claim 6, wherein the electrochromic layer is made of titanium dioxide (TiO ₂ ), zinc oxide (ZnO) or tungsten oxide (WO ₃ ), and the first and second electrode layers are made of graphene, ITO, Wire, silver nanomesh, PEDOT: PSS, or a combination thereof.
The flexible multi-functional laminate according to claim 6, wherein the electrochromic layer comprises tungsten oxide (WO ₃ ) / electrolyte layer / NiO 2.
The lithium _secondary battery according to claim 8, wherein the electrolyte layer comprises a Ta ₂ O ₅ layer, Li ₃ PO ₄ , LiNBO ₃ , Li _{3 + x} PO _{4 - x} N _x (LiPON), LiVO ₃ / SiO ₂ / Li ₄ SiO ₄ -Li ₃ VO ₄ (LVSO) layer is selected.
A first step of forming a first functionalized graphene layer on top of the first flexible substrate and a second graphene layer on the bottom;
A second step of depositing vanadium dioxide (VO ₂ ) on one surface of the first functionalized graphene layer / flexible substrate / second functionalized graphene layer of the first functionalized graphene layer formed in the above step to form a vanadium dioxide layer;
A third step of forming a third graphene layer on one side of the second flexible substrate;
A laminate of a vanadium dioxide layer / a first functionalized graphene layer / a flexible substrate / a second graphene layer laminate formed in the second step, a PDLC layer, a third graphene layer / a second flexible substrate laminate formed in the third step And a fourth step of producing a laminate comprising a vanadium dioxide layer / a first functionalized graphene layer / a flexible substrate / a second graphene layer / a PDLC layer / a third graphene layer / a second flexible substrate layer For producing a multifunctional laminate.
The method of claim 10, wherein the first step comprises: a 1-1 step of forming a graphene layer on the first substrate;
A first step of functionalizing the graphene layer formed in the step 1-1 to form a functionalized first functionalized graphene layer;
Laminating the flexible substrate to form a laminate including the first substrate / the first functionalized graphene layer / the flexible substrate;
Removing the first base material from the laminate formed in the step 1-3 by using an etching method and simultaneously transferring the first functionalized graphene layer onto the flexible base material to form a first functionalized graphene layer / (1-4);
(1-5) forming a second graphene layer on the second substrate;
The first functionalized graphene layer / flexible substrate formed in the step 1-4 is laminated to form a laminate comprising a second substrate / a second graphene layer / a flexible substrate / a first functionalized graphene, Step 6;
And a step 1-7 of removing the second base material from the laminate formed in the step 1-6 by using the etching method and simultaneously transferring the second graphene layer onto the flexible base material. A method for manufacturing a multifunctional laminate for windows.
[10] The method of claim 10, wherein the third step comprises: a third step of forming a third graphene layer on the third substrate;
Laminating the flexible substrate to form a laminate including a third substrate / a third graphene layer / a flexible substrate;
Removing the third base material from the laminate formed in the step 3-3 by using an etching method and simultaneously transferring the third graphene layer onto the flexible base material to form a third functionalized graphene layer / And a third step of forming the flexible multi-functional laminate body.
A first flexible substrate having at least one layer above the first functionalized graphene layer and a first electrode layer below the functionalized substrate;
A vanadium dioxide (VO2) layer formed on one side of the first functionalized graphene layer;
A PDLC layer stacked on the other surface of the electrode layer;
A second electrode layer laminated on the PDLC layer;
And a second flexible substrate having the second electrode layer laminated thereon.
The electrochromic device according to claim 13, wherein the electrochromic layer is made of titanium dioxide (TiO ₂ ), zinc oxide (ZnO) or tungsten oxide (WO ₃ ), and the first and second electrode layers are made of graphene, ITO, Wire, silver nanomesh, PEDOT: PSS, or a combination thereof.
The flexible multi-functional laminate of claim 13, wherein the electrochromic layer comprises tungsten oxide (WO ₃ ) / electrolyte layer / NiO 2.
The method according to any one of claims 6 to 9, further comprising a protective layer formed on the vanadium dioxide layer and / or under the ITO electrode layer, wherein the protective layer comprises at least one of polymethylnaphthacrylate (PMMA), polyvinylidene fluoride (PVDF) a multifunctional laminate for a flexible smart window which is at least one selected from the group consisting of polystyrene-co-PMMA-co-PS, photoresist (PR), electroresist, SiOx, TiOx, TiOx-Ag, ITO, FTO, .
14. The method of claim 13, further comprising a protective layer formed on the vanadium dioxide layer, wherein the protective layer comprises at least one of polymethylnaphthacrylate (PVMA), polyvinylidene fluoride (PVDF), polystyrene- photoresist, ER (electroresist), SiOx, TiOx, TiOx-Ag, ITO, FTO, or AlOx.

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