KR20180099962A - Smart glass including vanadium dioxide film and method for manufactruing thereof - Google Patents

Abstract

According to an embodiment of the present invention, smart glass comprises: a flexible substrate; a TiO_2 layer formed on the flexible substrate; and a vanadium dioxide film formed on the TiO_2 layer, and deposited and heat-treated at a temperature less than 175°C.

Description

TECHNICAL FIELD [0001] The present invention relates to a smart glass including a vanadium dioxide thin film and a method of manufacturing the same. [0002]

The present invention relates to a smart glass including a vanadium dioxide thin film and a method of manufacturing the same, and more particularly, to a flexible smart glass having a vanadium dioxide thin film and a method of manufacturing the same.

In recent years, with the rapid increase in energy consumption, rising oil prices, environmental problems caused by global warming, exhaustion due to limitations of fossil energy reserves and rising prices, and serious environmental problems such as air pollutant discharge and global warming, And smart windows that can effectively manage heat insulation are attracting much attention.

In addition, considering that the energy lost in windows is 45% of the energy lost in the entire building, it is urgent to develop a new smart window technology that can minimize heat loss.

As a functional glass applicable to smart windows, vanadium dioxide (VO ₂ , vanadium dioxide) is attracting attention. Vanadium dioxide is a material having a metal-insulator transition (MIT) characteristic and a thermochromic characteristic, and optical characteristics and electrical characteristics change near the phase transition temperature.

Vanadium Dioxide (VO ₂ ) has a monoclinic phase structure below the phase transition temperature of 68 ℃. As a result, it is optically transmitted through the IR region and becomes electrically nonconductive. On the other hand, it changes from a phase transition temperature to a rutile phase structure, optically shields the IR region, and becomes electrically conductive. This structural change phenomenon is called a metal-insulator transition (MIT) phenomenon.

Conventional vanadium dioxide thin films are prepared by depositing a vanadium dioxide thin film on a substrate and then heat-treating the substrate. At least 400 ° C of heat is applied to the vanadium dioxide thin film for a long time. Particularly, considering the temperature rise / down time of the chamber for reducing the reactivity with the atmosphere, the vanadium dioxide thin film is heat-treated for several hours. However, when the high-temperature deposition method is used, the crystallinity of the vanadium dioxide thin film can be improved. However, since there is a restriction on the material of the base substrate and a high processing cost, it is suitable for manufacturing a large- not.

Korean Patent Publication No. 2009-0090839, "Method for forming vanadium oxide film using atomic layer deposition method" Korean Patent Publication No. 2015-011214, "Stabilization Technology of Thermodynamically Unstable Insulator Phase in Metal-Insulator Phase Transition Material at Room Temperature by Simple Oxygen Control"

SUMMARY OF THE INVENTION An object of the present invention is to provide a smart glass including a vanadium dioxide thin film having good amorphous properties without forming a base substrate, and a method for manufacturing the same, by forming a vanadium dioxide thin film by a low temperature deposition method.

Smart glass according to an embodiment of the present invention include TiO ₂ layer and the deposition and heat treatment dioxide vanadium thin film in the TiO ₂ layer is formed on a temperature not higher than 175 ℃ formed on a flexible substrate, the flexible substrate.

Here, the vanadium dioxide thin film may be an amorphous thin film.

Here, the vanadium dioxide thin film may be deposited using a sputtering apparatus in an atmosphere of argon (Ar) and oxygen (O ₂ ) at a temperature of 175 ° C and a pressure of 6 mtorr.

Here, the partial pressure of oxygen (O ₂ ) may be 0.275 sccm (cm ³ / min).

Here, the flexible substrate may be a polyimide substrate.

A smart glass manufacturing method according to an embodiment of the present invention includes the steps of preparing a flexible substrate, depositing a TiO ₂ layer on the flexible substrate, depositing a vanadium dioxide thin film on the TiO ₂ layer at a temperature of 175 ° C or lower .

Here, the step of depositing the vanadium dioxide thin film may include depositing a thin film while maintaining the pressure of the chamber at 6 mtorr with a partial pressure of 10 sccm of argon (Ar) gas and a partial pressure of 0.275 sccm of oxygen (O ₂ ) gas.

Here, the step of depositing the vanadium dioxide thin film may include a heat treatment at 175 ° C for 2 hours under argon (Ar) gas at a partial pressure of 10 sccm.

The step of depositing the TiO ₂ layer on the flexible substrate may include depositing a layer having a thickness of 200 nm on the flexible substrate using ION (Ion-beam Assisted Deposition) equipment.

Here, the flexible substrate may be a polyimide substrate.

Example smart glass production process according to the present invention is maintaining the step, step, flexible substrate on which is deposited the TiO ₂ layer to deposit the TiO ₂ layer to the flexible substrate to prepare the flexible substrate at a 175 ℃ , Fixing the vanadium target to a position of 15 cm from the flexible substrate on which the TiO ₂ layer is deposited, discharging the vacuum in the sputter chamber to 3 × 10 ^-6 torr, and then performing a partial pressure of 10 sccm of argon gas and a partial pressure of 0.275 sccm of oxygen gas Maintaining the pressure at 6 mTorr, applying a sputtering power of 100 W to form a plasma on the vanadium target, depositing the vanadium dioxide thin film to a thickness of 50 nm, and then subjecting to heat treatment at 175 캜 for 2 hours under a partial pressure of 10 sccm of argon gas.

According to an embodiment of the present invention, a flexible smart glass on which a vanadium dioxide thin film is formed is provided.

In addition, according to the embodiment of the present invention, it is possible to manufacture a smart glass using a flexible base substrate while maintaining a good amorphous property for MIT characteristics of the vanadium dioxide thin film by forming the low temperature deposition method at 175 ° C or less.

1 is a cross-sectional view of a smart glass according to an embodiment of the present invention.
2A and 2B are schematic diagrams of MIT characteristics of a smart glass according to an embodiment of the present invention.
3 is a flowchart of a smart glass manufacturing method according to an embodiment of the present invention.
4 is a schematic view of a sputter apparatus for depositing vanadium dioxide according to an embodiment of the present invention.
5 is a hysteresis curve of a smart glass manufactured according to an embodiment of the present invention.
6 is a graph showing binding energy of a vanadium dioxide thin film produced according to an embodiment of the present invention.
7 is a graph depicting a depression profile of a vanadium dioxide thin film produced according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and accompanying drawings, but the present invention is not limited to or limited by the embodiments.

It is to be understood that when an element or layer is referred to as being "on" or " on "of another element or layer, All included. On the other hand, when a device is referred to as "directly on" or "directly above ", it does not intervene another device or layer in the middle.

The terms spatially relative, "below", "beneath", "lower", "above", "upper" May be used to readily describe a device or a relationship of components to other devices or components. Spatially relative terms should be understood to include, in addition to the orientation shown in the drawings, terms that include different orientations of the device during use or operation. For example, when inverting an element shown in the figure, an element described as " below or beneath "of another element may be placed" above "another element. Thus, the exemplary term "below" can include both downward and upward directions. The elements can also be oriented in different directions, in which case spatially relative terms can be interpreted according to orientation.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is noted that the terms "comprises" and / or "comprising" used in the specification are intended to be inclusive in a manner similar to the components, steps, operations, and / Or additions.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. And terminologies used herein are terms used to properly represent embodiments of the present invention, which may vary depending on the user, intent of the operator, or custom in the field to which the present invention belongs. Therefore, the definitions of these terms should be based on the contents throughout this specification.

Hereinafter, a smart glass according to an embodiment of the present invention will be described with reference to the drawings.

1 is a cross-sectional view of a smart glass according to an embodiment of the present invention.

On a smart glass is flexible substrate 110, TiO ₂ layer 120, and the TiO ₂ layer 120 is formed on the flexible substrate 110 according to an embodiment of the present invention as shown in Figure 1 And a vanadium dioxide thin film 130 deposited and heat-treated at a temperature of 175 ° C or lower.

The flexible substrate 110 may be a freely bendable plastic substrate, preferably a polyimide substrate, but is not limited thereto.

A TiO ₂ layer 120 is formed on the base substrate 110. Here, the TiO ₂ layer 120 has temperature stability and functions as a seed layer in forming the vanadium dioxide thin film 130.

A vanadium dioxide thin film 130 is formed on the TiO ₂ layer 120 and is deposited and heat-treated at a temperature of 175 ° C or lower. As such, the vanadium dioxide thin film 130 is formed on the TiO ₂ layer 120 functioning as a seed layer, so that the vanadium dioxide thin film 130 has good amorphousness, that is, amorphousness even if formed by low temperature deposition.

A vanadium dioxide thin film 130 is formed on the TiO ₂ layer 120 and is deposited and heat-treated at a temperature of 175 ° C or lower. Specifically, the vanadium dioxide thin film 130 was irradiated with a 100 W power to a vanadium target in an atmosphere of argon (Ar) and oxygen (O ₂ ) at 175 ° C. and 6 mTorr using a DC / RF reactive magnetron sputtering apparatus And is heat-treated in an argon (Ar) atmosphere at 175 DEG C or less. At this time, the partial pressure of oxygen (O ₂ ) may be 0.275 sccm (cm ³ / min).

At present, it is preferable to use a compound such as VO ₂ , V ₂ O ₃ , V ₃ O ₅ , V ₄ O ₇ , V ₆ O ₁₁ , V ₅ O ₉ , V ₆ O ₁₃ , V ₄ O ₉ , V ₃ O ₇ , V ₂ O ₅ Various vanadium oxides are present, but the metal-insulator transition (MIT) and thermochromic properties are only present in vanadium dioxide (VO ₂ ). That is, the vanadium dioxide (VO ₂ ) optically transmits the IR region and becomes electrically nonconductive at a phase transition temperature or lower, and when the temperature is above the phase transition temperature, the IR region is optically cut off and becomes electrically conductive. This phase transition phenomenon is known to be caused by the change of the VOV bond of vanadium dioxide from a covalent bond to a metal bond.

In order to deposit vanadium dioxide on a flexible substrate having the above-mentioned MIT characteristics and thermochromic characteristics, it is possible to deposit at a relatively low temperature and to maintain the properties of the material even after deposition. The vanadium dioxide according to the embodiment of the present invention is an amorphous thin film due to the characteristics of the flexible substrate.

Especially, the substrate of the flexible plastic substrate has a low melting point, so that the substrate is deformed during a general substrate processing. However, in the smart glass according to the embodiment of the present invention, the vanadium dioxide thin film is deposited at a relatively low temperature of 175 ° C Deposition is possible on a flexible substrate.

2A and 2B are schematic diagrams of MIT characteristics of a smart glass according to an embodiment of the present invention.

Referring to FIG. 2A, when sunlight is irradiated in an environment below the phase transition temperature as in the winter, the smart glass 100 transmits visible light and IR light in the sunlight and reflects some light. Accordingly, the smart glass 100 can transmit the infrared ray in a low-temperature environment such as winter so as to increase the indoor temperature and prevent radiant heat in the room from flowing out to the outside.

Referring to FIG. 2B, when sunlight is irradiated in an environment above the phase transition temperature as in the summer, the smart glass 100 transmits visible light in the sunlight and reflects light in the IR area and some other light. Therefore, the smart glass 100 can prevent infrared rays from being reflected into the room by reflecting infrared light in a high temperature environment such as summer.

By manufacturing the smart glass 100 as described above in a large area and applying it to a smart window, it is possible to reduce the heating and cooling energy of the room.

Hereinafter, a method of manufacturing a smart glass according to another embodiment of the present invention will be described with reference to FIGS. 3 and 4. FIG.

3 is a flowchart of a smart glass manufacturing method according to an embodiment of the present invention.

4 is a schematic view of a sputter apparatus for depositing vanadium dioxide according to an embodiment of the present invention.

Smart glass production process according to the embodiment of the present invention as shown in Figure 3 in the TiO ₂ layer in step 175 ℃ below a temperature of depositing a TiO ₂ layer in step, the flexible substrate to prepare the flexible substrate And depositing a vanadium dioxide thin film.

The step of depositing a TiO ₂ layer on the flexible substrate includes depositing a 200 nm thick layer on the flexible substrate using an ION (Ion-beam Assisted Deposition) equipment.

Specifically, after the flexible substrate 110 is mounted on an ION (Ion beam Assisted Deposition) chamber, the TiO ₂ layer 120 is vacuum deposited, and ions are ion-gunned onto the TiO ₂ layer 120 And the TiO ₂ layer 120 is formed into a dense film shape.

The TiO ₂ layer 120 having a thickness of 200 nm can be formed by performing heat treatment at 175 ° C for several minutes. The TiO ₂ layer 120 thus produced functions as a seed layer for a vanadium dioxide thin film to be formed in a subsequent process.

The step of depositing the vanadium dioxide thin film on the TiO ₂ layer at a temperature of 175 ° C or less uses a DC / RF reactive magnetron sputter 10 as shown in FIG.

Specifically, the substrate on which the flexible substrate 110 and the TiO ₂ layer 120 are sequentially formed is mounted on the holder 12 in the vacuum chamber 11, and the vanadium target 14 is mounted on the sputter gun 13. Here, the structure 410 is dropped from the vanadium target 14 by about 15 cm. The vacuum in the vacuum chamber 11 was extracted to 3 × 10 ^-6 torr by using a vacuum pump 17 and the substrate was maintained at a temperature of 175 ° C., (18).

At this time, the argon gas supplied through the argon gas container 16a is controlled to a partial pressure of 10 sccm and the oxygen gas to a partial pressure of 0.275 sccm by using an MFC (Mass Flow Controller) 15, and the pressure in the vacuum chamber 11 is controlled to 6 mTorr, and then a power of 100 W is supplied to the vanadium target 14 to generate plasma. In this manner, the vanadium dioxide thin film 130 can be deposited to a thickness of 50 nm for 1 hour and 30 minutes.

Then, the argon gas supplied through the argon gas container 16a is adjusted to a partial pressure of 10 sccm, and the vanadium dioxide thin film 130 is heat-treated at a temperature of 175 DEG C for about 2 hours.

By performing the vapor deposition and heat treatment process of the vanadium dioxide thin film 130 at a low temperature of 175 ° C or lower, it is possible to deposit the vanadium dioxide thin film on the flexible substrate 110 and manufacture a large-area smart glass.

5 is a hysteresis curve of a smart glass manufactured according to an embodiment of the present invention.

As shown in FIG. 5, the resistance change of each smart glass was measured while heating and cooling the ambient temperature of the smart glass according to the embodiment of the present invention.

Smart glass has a hysteresis characteristic of 47.9 ° C (Tc) during heating and cooling. It can be seen that the vanadium dioxide thin film (VO ₂ ) contained in the smart glass shows the phase transition characteristic at 47.9 ° C.

6 is a graph showing binding energy of a vanadium dioxide thin film produced according to an embodiment of the present invention.

7 is a depth profile graph of a vanadium dioxide thin film produced according to an embodiment of the present invention.

As shown in FIGS. 6 and 7, the binding energy of the thin film and the depth profile of the thin film were measured. As a result, it can be confirmed that the thin film was vanadium dioxide.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. This is possible.

Therefore, the scope of the present invention should not be limited by the described embodiments, but should be determined by the equivalents of the appended claims, as well as the appended claims.

110 base substrate
120 TiO ₂ layer
130 vanadium dioxide thin film

Claims (12)

A flexible substrate;
A TiO ₂ layer formed on the flexible substrate; And
And a vanadium dioxide thin film formed on the TiO ₂ layer and deposited and heat-treated at a temperature of 175 ° C or less. The method according to claim 1,
Wherein the vanadium dioxide thin film is an amorphous thin film. The method according to claim 1,
Wherein the vanadium dioxide thin film is deposited in an atmosphere of argon (Ar) and oxygen (O ₂ ) at 175 ° C and 6 mtorr using a sputtering equipment. The method of claim 3,
Wherein the partial pressure of oxygen (O ₂ ) is 0.275 sccm (cm ³ / min). The method according to claim 1,
Wherein the flexible substrate is a polyimide substrate. Preparing a flexible substrate;
Depositing a TiO ₂ layer on the flexible substrate;
At temperatures below 175 ℃ smart glass manufacturing method comprising the steps of depositing a vanadium dioxide thin film on the TiO ₂ layer. The method according to claim 6,
Wherein the step of depositing the vanadium dioxide thin film includes depositing a thin film while maintaining the pressure of the chamber at 6 mtorr with a partial pressure of 10 sccm of argon (Ar) gas and a partial pressure of 0.275 sccm of oxygen (O ₂ ) Glass manufacturing method. 8. The method of claim 7,
Wherein the step of depositing the vanadium dioxide thin film includes a step of heat-treating at 175 캜 for 2 hours under argon (Ar) gas at a partial pressure of 10 sccm. The method according to claim 6,
Wherein depositing a TiO ₂ layer on the flexible substrate comprises depositing a 200 nm thick layer on the flexible substrate using an Ion-beam Assisted Deposition (IAD) equipment. The method according to claim 6,
Wherein the flexible substrate is a polyimide substrate. Preparing a flexible substrate;
Depositing a TiO ₂ layer on the flexible substrate;
Maintaining the flexible substrate on which the TiO ₂ layer is deposited at 175 ° C;
Fixing the vanadium target at a position of 15 cm from the flexible substrate on which the TiO ₂ layer is deposited;
A vacuum in the sputtering chamber 3 × 10 ^{- 6} torr and then discharged to maintaining the argon gas partial pressure of 10sccm and oxygen gas and the chamber pressure with a partial pressure 0.275sccm 6mtorr;
Applying a sputter power of 100 W to form a plasma on the vanadium target;
Depositing the vanadium dioxide thin film to a thickness of 50 nm, and then subjecting the thin vanadium dioxide to heat treatment at 175 ° C for 2 hours under a partial pressure of 10 sccm of argon gas. A smart glass produced by the method of claim 11.

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