KR102331951B1 - Methods for manufacturing nanostructured tungsten oxide thin film and nanostructured tungsten oxide thin film made by the same - Google Patents

Abstract

The technology disclosed herein provides a method for manufacturing a nanostructured tungsten oxide thin film having a predetermined shape and a small amount of deformation during sintering. According to the method for manufacturing a nanostructured tungsten oxide thin film according to an embodiment of the technology disclosed herein, it is possible to reproducibly provide a tungsten oxide thin film having a nanostructure of a certain shape, and it is possible to form a three-dimensional nanostructure through an iterative process .
Due to the large surface area of the nanostructured tungsten oxide disclosed herein, there is an effect of contributing to the improvement of the efficiency of electrochromic, display, hydrogen production, water decomposition, secondary battery, chemical sensor, gas sensor, and the like.

Description

Nanostructured tungsten oxide thin film manufacturing method and nanostructured tungsten oxide thin film manufactured thereby

The present invention relates to a method for manufacturing a nanostructured tungsten oxide thin film, and more particularly, to a method for manufacturing a nanostructured tungsten oxide thin film having a predetermined shape and a small amount of deformation during sintering, and to a nanostructured tungsten oxide thin film manufactured thereby.

Tungsten oxide is a metal oxide semiconductor with a band gap of 2.8 eV. Recently, it has been used as a material for hydrogen production electrodes through water decomposition, an electrode material for an electrochromic display or smart window, a material for a gas sensor electrode, a chemical sensor, and a secondary battery. is being applied

When tungsten oxide is manufactured in a nanostructure, the surface area with the reactant becomes large, so that hydrogen production efficiency, electrochromic reaction rate, sensitivity of gas sensing, etc. are increased.

In the conventional case, nanostructured tungsten oxide was prepared by hydrothermal synthesis (J. Mater. Chem. A, 2013, 1,3479). A tungsten oxide having a nanorod or nanosheet structure was prepared on the substrate by immersing the substrate on which the seed layer was formed in a hydrothermal synthesis solution and maintaining it at a high temperature for a certain period of time. However, in this case, there is a problem in that the nanostructures are randomly arranged on the substrate, the size of the nanostructures is not constant, and the reproducibility is low.

In another method, nanostructured tungsten oxide was fabricated through a nanoimprint method (Advanced Functional Materials 23(17):2201-2211). After forming a precursor thin film by applying a precursor for tungsten oxide on a substrate, a mold engraved with nanostructures was brought into contact with the thin film. A tungsten oxide having a nanostructure was prepared by applying temperature, pressure, ultraviolet light, etc. to the substrate in contact with the mold to form the complementary structure of the nanostructure engraved on the mold on the precursor thin film. However, in this case, since a large amount of solvent is contained in the precursor thin film formed on the substrate, there is a problem in that the shape of the nanostructure of the tungsten oxide is severely deformed after sintering.

Therefore, there is a need for a method for manufacturing a nanostructured tungsten oxide thin film having a certain shape and having a small amount of deformation during sintering.

One of the objects of the present invention is to provide a method for manufacturing a nanostructured tungsten oxide thin film having a certain shape and a small amount of deformation during sintering and to provide a nanostructured tungsten oxide thin film prepared thereby, according to the technical spirit of the technology disclosed in the present specification. The technical task to be achieved by the method for manufacturing the nanostructured tungsten oxide thin film is not limited to the task for solving the above-mentioned problems, and another task not mentioned can be clearly understood by those skilled in the art from the following description will be.

In order to achieve the above-described exemplary task, an embodiment of the technology disclosed herein provides a method for manufacturing a nanostructured tungsten oxide thin film. The method for manufacturing the nanostructured tungsten oxide thin film includes: a first step of forming a tungsten oxide precursor thin film on a nanomold; a second step of forming an adhesive layer on the substrate; and a third step of transferring the precursor thin film formed on the nano-mold onto the substrate on which the adhesive layer is formed.

In one embodiment, the first step, preparing a precursor resin containing tungstic acid; Preparing a nano-mold imprinted with a nano structure; and applying the precursor resin to the nano-mold.

In one embodiment, the method for manufacturing the nanostructured tungsten oxide thin film comprises: a fourth step of separating the nanomold; and a fifth step of sintering, and repeating the first to fifth steps.

Another embodiment of the present invention provides a nanostructured tungsten oxide thin film in order to achieve the above-described exemplary task. This nanostructured tungsten oxide thin film is prepared by the first to fifth steps and in one embodiment, the nanostructured tungsten oxide thin film is manufactured by the repeating process of the first to fifth steps. will be.

According to the method for manufacturing a nanostructured tungsten oxide thin film according to an embodiment of the technology disclosed herein, it is possible to reproducibly provide a tungsten oxide thin film having a nanostructure of a certain shape. In addition, it is possible to form a three-dimensional nanostructure through an iterative process.

In addition, according to the embodiment of the technology disclosed in the present specification, due to the large surface area of the nanostructured tungsten oxide, the effect of contributing to the improvement of the efficiency of electrochromic, display, hydrogen production, water decomposition, secondary battery, chemical sensor, gas sensor, etc. have.

On the other hand, the effect that can be achieved by the method for manufacturing a nanostructured tungsten oxide thin film according to an embodiment of the technology disclosed in the present specification is not limited to those mentioned above, and other effects not mentioned can be obtained from those skilled in the art from the description below. can be clearly understood by

In order to more fully understand the drawings cited herein, a brief description of each drawing is provided.
1 is a flowchart of a method for manufacturing a nanostructured tungsten oxide thin film according to an embodiment of the technology disclosed herein.
Figure 2 is a process diagram showing in cross section the process of the nanostructure tungsten oxide thin film manufacturing method according to an embodiment of the technology disclosed herein.
Figure 3 is a process diagram showing a cross-section of the repeating process of the nanostructure tungsten oxide thin film manufacturing method according to an embodiment of the technology disclosed herein.
4 to 6 are photographs of a nanostructured tungsten oxide thin film by a method for manufacturing a nanostructured tungsten oxide thin film according to an embodiment of the technology disclosed herein.
7 is a photograph showing a hexa-hole pattern of a nanostructured tungsten oxide thin film according to an embodiment of the technology disclosed herein.
8 is a graph showing an ultraviolet-visible light absorption spectrum of a nanostructured tungsten oxide thin film and a comparative example according to an embodiment of the technology disclosed herein.
9 is an X-ray diffraction analysis (XRD) graph of a nanostructured tungsten oxide thin film according to an embodiment of the technology disclosed herein.

Since the technology disclosed in this specification can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings, and this will be described in detail through the detailed description. However, this is not intended to limit the technology disclosed herein to specific embodiments, and it is understood that the technology disclosed herein includes all modifications, equivalents and substitutes included in the spirit and scope of the technology disclosed herein. should be

In describing the technology disclosed in the present specification, if it is determined that a detailed description of a related known technology may unnecessarily obscure the subject matter of the technology disclosed in the present specification, the detailed description thereof will be omitted.

It will be understood that when an element, such as a layer, region, or substrate, is referred to as being “on” another component in the present disclosure, it may be directly on the other element or intervening elements may be present therebetween. will be able

In the present disclosure, the nanostructure is a concept including a shape having a specific shape of a nanometer size, not a general spherical or aggregated particle shape. The nano-mold may be formed of a metal such as Al, Cr, Ag, Cu, Ni, Co, Mo, or an alloy thereof, and in addition to various metal oxides. In addition, it may be made of various materials such as a silicon wafer or a polymer material such as PDMS, h-PDMS, PVC, PFPE, and PUA.

1 is a flowchart of a method for manufacturing a nanostructured tungsten oxide thin film according to an embodiment of the technology disclosed herein, and FIG. 2 is a cross-sectional view showing the process of a method for manufacturing a nanostructured tungsten oxide thin film according to an embodiment of the technology disclosed herein It is a process diagram.

Referring to FIG. 1 , a method for manufacturing a nanostructured tungsten oxide thin film (S100, hereinafter, a nanostructured tungsten oxide thin film manufacturing method) according to an embodiment of the technology disclosed herein is a method for forming a tungsten oxide precursor thin film on a nanomold A first step (S110), a second step (S120) of forming an adhesive layer on the substrate, and a third step (S130) of transferring the precursor thin film formed on the nano-mold onto the substrate on which the adhesive layer is formed a fourth step of separating the nano-mold (S140); and a fifth step (S150) of sintering may be further included, and the first step (S110) to the fifth step (S150) may be repeated.

Each step will be described below.

First step (S110)

Referring to FIG. 2 , the first step (S110) of forming a tungsten oxide precursor thin film on the nanomold 110 includes preparing a precursor resin (A) containing tungstic acid, and the nanostructure imprinted with the nanostructure. It may include preparing the mold 110 and applying the precursor resin (A) to the nano-mold 110 .

The precursor resin (A) containing tungstic acid may be, for example, _{a hydrogen peroxide solution containing 2 to 30% of tungsten oxide (H 2} WO ₄ ) and 1 to 10% of polyvinyl alcohol (PVA), but must be limited thereto it's not going to be

The precursor resin (A) in this embodiment is characterized in that the solvent content is low, and there is an advantage that the shape of the nanostructure can be maintained even after sintering. The solvent content of the precursor resin (A) may be preferably 95% or less.

As a method of forming the precursor thin film on the nano-mold 110 , it may be formed by spin coating, bar coating, spray coating, or inkjet printing method, but it must be It is not limited.

Second step (S120)

As a second step of forming an adhesive layer 140 on the substrate 120 , as exemplarily shown in FIG. 2 , an adhesive layer 140 is formed on the substrate 120 .

The substrate 120 is not particularly limited as long as it is an insulator and on which the adhesive layer 140 can be easily deposited, and may be used by depositing a desired number of layers.

Such substrates include, for example, oxide substrates such as _{SiO 2} substrates, ITO substrates, SnO ₂ substrates, TiO ₂ substrates, Al ₂ O _{3 substrates;} From the group consisting of Cu, Ni, Fe, Pt, Al, Co, Ru, Pd, Cr, Mn, Au, Ag, Mo, Rh, Ta, Ti, W, U, V, Zr, Ir and combinations thereof a selected metal substrate; Polyethylene Terephthalate (PET), Polyethylene Sulfone (PES), Polymethyl Methacrylate (PMMA), Polyimide, Polyehylene Naphthalate (PEN), Polycarbonate flexible substrates such as (Polycarbonate; PC); or a glass substrate; etc.

In this embodiment, the adhesive layer 140 may be formed to have a thickness of approximately 50 nm to 500 nm. When the thickness of the adhesive layer is within the above range, the occurrence of defects due to pressing may be prevented and the adhesive strength of the adhesive layer may be properly maintained. The composition of the adhesive layer 140 may be an aqueous solution containing 6 to 25% of polyvinyl alcohol (PVA) and 1.25% to 50% of hydrogen peroxide.

The adhesive layer 140 may include the substrate 120 and the nanostructured tungsten oxide thin film to be formed on the substrate 120 , or the tungsten oxide thin film formed on the substrate 120 and the nanostructured tungsten oxide thin film to be formed on the substrate 120 . may exist in between.

Such an adhesive layer may be, for example, polyvinyl alcohol (PVA), polyvinylpyrrolidone (poly(vinylpyrrolidone), PVP), polyaniline (PANI), poly(diallyldimethylammonium chloride) , PDDA), polyethylene oxide (poly(ethylene oxide), PEO), polyethylene imine (poly(ethylene imine), PEI), poly(allylamine hydrochloride), PAH), poly(acrylic acid) )), Nafion (Nafion, tetrafluoroethylene-perfluoro-3,6-dioxa-4-methyl-7-octenesulfonic acid copolymer), and the like.

As a method of forming the adhesive layer 140 on the substrate 120 , spin coating, dip coating, bar coating, spray coating, doctor blade ), may be formed by an inkjet printing method, but is not necessarily limited thereto.

Third step (S130)

Referring to FIG. 2, in the first step (S110), the mold coated with the precursor resin (A) is brought into contact with the substrate 120 on which the adhesive layer 140 is formed in the second step (S120) to transfer the precursor thin film ( transfer).

Examples of such a transfer method include an air knife method in which a roll is used on one side and a sheet or the like is pressed onto a roll or the like by air pressure such as air or nitrogen from the side opposite to the roll; a method of attaching a sheet or the like to a roll or the like with an electric force by applying static electricity or the like; and a method of mechanically contacting the pressure roll.

Preferably, a temperature of 200° C. or less and a pressure of 4 bar or less may be applied for about 3 minutes.

Fourth step (S140) and fifth step (S150)

As shown in FIG. 2 , the nano-mold 110 is separated from the substrate 120 to which the precursor thin film is transferred. The separated nano-mold 110 may be reused as the nano-mold 110 in the first step ( S110 ).

Referring to FIG. 2 , the precursor particles receive light energy and are sintered while the temperature rises high. At this time, the adhesive layer 140 present on the substrate 120 is decomposed by heat on the contrary.

This sintering temperature is characterized in that 300 ℃ ~ 1,000 ℃.

iterative process

Referring to FIG. 3 , the nanostructured tungsten oxide thin film prepared by the first step (S110) to the fifth step (S150) is used as the substrate 120 of the second step (S120) in the first step ( S110) to the fifth step (S150) may be repeated.

Through this repeated process, it is possible to form a three-dimensional nanostructure.

Nanostructured Tungsten Oxide Thin Film

Referring to FIG. 2 , the nanostructured tungsten oxide thin film is manufactured by the first steps ( S110 ) to the fifth steps ( S150 ).

The nanostructured tungsten oxide thin film may be used as the substrate 120 in the second step (S120) and manufactured by repeating the first steps (S110) to the fifth step (S150).

Pictures of the nanostructured tungsten oxide thin film prepared through this process are shown in FIGS. 4 to 6 . 4 is a photograph after separation of the nano-mold in the fourth step (S140), FIG. 5 is a cross-sectional photograph of the linear tungsten oxide after sintering in the fifth step (S150), and FIG. 6 is an adhesive layer of the nanostructured tungsten oxide thin film It's a photo.

Due to the large surface area of the nanostructured tungsten oxide thin film, there is an effect of contributing to the improvement of the efficiency of electrochromic, display, hydrogen production, water decomposition, secondary battery, chemical sensor, gas sensor, and the like.

Hereinafter, examples will be described in detail to help the understanding of the technology disclosed in the present specification. However, the following examples only illustrate the content of the technology disclosed in the present specification, and the scope of the technology disclosed in the present specification is not limited to the following examples. The embodiments of the technology disclosed herein are provided to more completely explain the present invention to those of ordinary skill in the art.

Example 1: Preparation of nanostructured tungsten oxide thin film

A precursor resin was prepared by dissolving 0.2 to 3 g of H ₂ WO _{4 and 0.1 to 1 g of PVA in hydrogen peroxide.} A nano-mold (PFPE; perfluoropolyether) imprinted with a nanostructure was used. The precursor resin was spin-coated at 1500 rpm for 15 seconds to form the nano-mold.

A composition obtained by dissolving 0.5 to 2.0 g of PVA and 0 to 4 ml of hydrogen peroxide in water was spin-coated at 3000 rpm for 45 seconds to form an adhesive layer to a thickness of 50-500 nm on a silicon substrate (thickness: 200 um, manufactured by SK Siltron), and the resin The precursor thin film was transferred by contacting the applied nano-mold and the substrate on which the adhesive layer was formed at 100° C. for 10 minutes.

Then, the nanomold was separated. 4 is a photograph of a structure in which the nano-mold is separated. After separation of the nano mold, sintered at 500 ° C. to prepare a tungsten oxide thin film having a nanostructure of a certain shape.

Example 2: Preparation of a three-dimensional nanostructured tungsten oxide thin film

On the nanostructured tungsten oxide thin film prepared under the same conditions and process as in Example 1, the composition of Example 1 was spin-coated at 3000 rpm for 45 seconds to form an adhesive layer to a thickness of 150 nm, and the resin of Example 1 was applied The precursor thin film was transferred by contacting the nano-mold and the substrate on which the adhesive layer was formed at 100° C. and 0.4 bar for 10 minutes.

Then, after separating the nano-mold, sintering at 500 ℃, and repeating the above process to prepare a tungsten oxide thin film having a three-dimensional nanostructure.

Confirmation of large surface area characteristics of nanostructured tungsten oxide thin film

Referring to FIG. 7 , it can be seen that a hexahole pattern is formed in the nanostructured tungsten oxide thin film prepared in Example 1. It can be seen that the light absorption of the patterned nanostructured tungsten oxide thin film is higher than that of the unpatterned tungsten oxide thin film (comparative example) (see FIG. 8 ). When the surface area increased by the nanopattern was calculated in a geometric way, it was confirmed that the surface area of the nanostructured tungsten oxide thin film prepared in Example 1 was about 1.1256 times wider than that of the tungsten oxide thin film of Comparative Example.

Confirmation of crystal structure of nanostructured tungsten oxide thin film

Referring to FIG. 9 , it can be confirmed that the nanostructured tungsten oxide thin film prepared in Example 1 has a WO _{3 monoclinic crystal structure.}

Although the present invention has been described in detail above, the scope of the technology disclosed in the present specification is not limited thereto, and various modifications and variations are possible within the scope without departing from the technical spirit of the technology disclosed in the present specification as described in the claims. It will be apparent to one of ordinary skill in the art.

110: nano mold
120: substrate
A: Precursor resin
B: adhesive layer

Claims (12)

A method for manufacturing a nanostructured tungsten oxide thin film, comprising:
A first step of forming a tungsten oxide precursor thin film on the nano-mold;
a second step of forming an adhesive layer on the substrate;
a third step of transferring the precursor thin film formed on the nano-mold onto the substrate on which the adhesive layer is formed;
a fourth step of separating the nano-mold; and
a fifth step of sintering;
It is characterized in that the first to fifth steps are repeated,
The composition of the adhesive layer is characterized in that it is an aqueous solution containing 6 to 25% of polyvinyl alcohol (PVA) and 1.25% to 50% of hydrogen peroxide,
The first step is
Comprising the step of preparing a precursor resin containing tungstic acid,
The precursor resin containing tungstic acid is characterized in that it is a hydrogen peroxide solution containing 2 to 30% tungstic acid and 1 to 10% polyvinyl alcohol (PVA),
A method for manufacturing a nanostructured tungsten oxide thin film. The method of claim 1,
The thickness of the adhesive layer, characterized in that 50nm ~ 500nm
A method for manufacturing a nanostructured tungsten oxide thin film. delete The method of claim 1,
wherein the adhesive layer is present between the substrate and the nanostructured tungsten oxide thin film to be formed on the substrate, or between the tungsten oxide thin film formed on the substrate and the nanostructured tungsten oxide thin film to be formed on the substrate
A method for manufacturing a nanostructured tungsten oxide thin film. The method of claim 1,
The first step is
Preparing a nano-mold imprinted with a nano structure; and
Further comprising the step of applying the precursor resin to the nano-mold
A method for manufacturing a nanostructured tungsten oxide thin film. The method of claim 1,
The precursor resin containing tungstic acid is characterized in that the solvent content is 95% or less.
A method for manufacturing a nanostructured tungsten oxide thin film. delete delete delete delete delete delete

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