KR20200037000A - Recovery of electrical properties and oxidation stability improvement method for two-dimensional materials - Google Patents

Abstract

The present invention relates to a method for recovering electrical properties and improving oxidation stability in a two dimensional material and, more specifically, to a method comprising the steps of: (a) preparing a MXene solution containing a transition metal carbide and a transition metal carbonitride, each of which has a two-dimensional structure; (b) forming the prepared MXene solution into a MXene film containing a composite material in a film form; (c) storing the formed MXene film at room temperature; (d) disposing the MXene film oxidized through the room temperature storage in vacuum equipment so as to use the MXene film; (e) injecting hydrogen gas into the vacuum equipment in which the MXene film has been disposed; and (f) annealing the MXene film to recover electric properties of the MXene film exposed to the injected hydrogen gas to a pre-oxidation level. Electrical properties of the MXene film, which have become poor due to oxidation at room temperature, can be recovered by annealing the MXene film with the exposure thereof to hydrogen gas in the vacuum equipment.

Description

Method of restoring electrical properties of 2D materials and improving oxidation stability {RECOVERY OF ELECTRICAL PROPERTIES AND OXIDATION STABILITY IMPROVEMENT METHOD FOR TWO-DIMENSIONAL MATERIALS}

The present invention relates to a method for recovering electrical properties and improving oxidation stability of a two-dimensional material, and more particularly, by annealing an oxidized maxine film at a high temperature, recovering electrical properties and recovering electrical properties of a two-dimensional material that improves oxidation stability. And a method for improving oxidation stability.

As one of the two-dimensional materials, the MAX phase (MAX phase, where M is a transition metal, A is a group 13 or 14 element, X is carbon and / or nitrogen) is a quasi-ceramic property MX, and a metal element A different from M is The combined crystals are excellent in physical properties such as electrical conductivity, oxidation resistance, and machinability. To date, more than 60 types of MAX phases are known to be synthesized.

The MAX phase is a two-dimensional material, but unlike graphite or metal dichalcogenide materials, the transition metal carbides are stacked with weak chemical bonds between element A and transition metal M between layers of each other. Therefore, it is difficult to transform into a two-dimensional structure using a general mechanical peeling method or a chemical peeling method.

However, in recent years, researchers led by Professor Michel W. Barsoum of Drexel University in 2011 used a hydrofluoric acid to selectively remove the aluminum layer from the MAX trader's three-dimensional titanium-aluminum carbide, resulting in a two-dimensional structure with completely different properties. Successful transformation. The researchers named the two-dimensional material obtained by exfoliating the MAX phase as "MXene." MXene has similar electrical conductivity and strength as graphene, and can be applied to various application technologies ranging from energy storage devices to biomedical applications and complexes.

However, such a maxine is dispersed in water to prepare a maxine solution, and this is formed into a film-like maxine film, so that it is oxidized by air and water during storage, so it is easy to lose its original properties.

Therefore, there is a need for a method capable of restoring the electrical properties of the maxine film oxidized by air and water and preventing oxidation from moisture or oxygen.

Patent Publication No. 10-2017-0036507 (2017.04.03.)

Technical problem to be achieved by the present invention is a two-dimensional material that improves the oxidation stability and recovery of the electrical properties of the maxine film by exposing the maxine film, which has been oxidized at room temperature and deteriorated in electrical properties, to hydrogen gas in a vacuum device to anneal at a high temperature. It is to provide a method of restoring electrical properties and improving oxidation stability.

The technical problems to be achieved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by those skilled in the art from the following description. There will be.

In order to achieve the above technical problem, a method for recovering electrical properties and improving oxidation stability of a two-dimensional material according to the present invention comprises: (a) preparing a maxine solution composed of a two-dimensional transition metal carbide and a transition metal carbonitride, (b ) Forming the prepared maxine solution into a maxine film composed of a composite material in the form of a film, (c) storing the formed maxine film at room temperature, and (d) using the oxidized maxine film through storage at room temperature. Placing in the vacuum equipment, (e) injecting hydrogen gas into the vacuum equipment in which the maxine film is placed, and (f) recovering electrical properties of the maxine film exposed to the injected hydrogen gas to a level before oxidation. To provide an annealing process for the maxin film.

In an embodiment of the present invention, the maxinic solution is Ti ₂ C, Ti ₃ C ₂ , V ₂ C, Nb ₂ C, (Ti _0.5 , Nb _0.5 ) ₂ CT _x , Ti ₃ CN, (V _0.5 , Cr _0.5 ) ₃ C ₂ , Ta ₄ C ₃ And any of Nb ₄ C ₃ may also be used. .

In the embodiment of the present invention, the maxinic solution may be formed of the formula M _n + ₁ X _n .

In an embodiment of the present invention, M in the formula of M _n + ₁ X _n may be a front transition metal.

In an embodiment of the present invention, X in the formula of M _n + ₁ X _n may also include at least one of carbon and nitrogen.

In the embodiment of the present invention, in step (b), the maxinic solution may be manufactured in a film form through spin coating, drop casting, and vacuum filtration.

In the embodiment of the present invention, in the step (f), the maxin film may be annealed for 20 minutes to 40 minutes at a temperature of 800 ° C to 1000 ° C.

In an embodiment of the present invention, the ratio of the sheet resistance value of the maxine film annealed through step (f) and the sheet resistance value formed through step (b) may have a ratio of 0.9 to 1.2.

In an embodiment of the present invention, the functional group bound to the surface of the maxine film may be one in which the proportion of fluorine is reduced through oxidation and reduction.

In an embodiment of the present invention, the maxine film may be formed by forming a solid network on the surface through annealing to prevent oxidation under the infiltration of oxygen and moisture.

In an embodiment of the present invention, the maxin film may be annealed at a temperature of 900 ° C. for 30 minutes to maintain a sheet resistance value of 3.1 times or less compared to an initial value.

In an embodiment of the present invention, the vacuum equipment includes a body part formed in a hollow cylindrical shape, a quartz tube provided so that the maxine film is disposed on top of the body part, and a maxine film disposed on the top of the quartz tube. A gas supply unit provided to supply the hydrogen gas at one lower end of the body portion so as to be exposed to the hydrogen gas, and the hydrogen gas supplied from the gas supply unit flows inside the body portion and contacts the maxine film and then discharges to the outside It is also possible to include an annealing portion which is disposed to surround the side wall of the body portion in which the quartz tube is disposed so that the maxima film is annealed, and a gas discharge portion provided at the other end of the body portion.

In an embodiment of the present invention, a pulse element may be configured as an electrode material through a stored pulse film through a method of recovering electrical properties and improving oxidation stability of the two-dimensional material.

According to an embodiment of the present invention, by oxidizing at room temperature, the annealing at a high temperature by exposing the maxine film, which has been deteriorated in electrical properties, to hydrogen gas in a vacuum equipment, thereby improving the recovery of the electrical properties of the maxine film and improving the oxidation stability. .

It should be understood that the effects of the present invention are not limited to the above-described effects, and include all effects that can be deduced from the configuration of the invention described in the detailed description or claims of the present invention.

1 is a flowchart of a method for recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention.
2 is a cross-sectional view of a vacuum device in which a maxine film of a method for recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention is disposed.
3 is a graph showing a sheet resistance ratio according to a change in temperature of a method for recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention.
4 is a graph showing a sheet resistance ratio according to a change in time in a method of recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention.
5 is a graph showing the recovery rate of sheet resistance according to the degree of oxidation of a method for improving electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention.
6 is a graph showing a change in sheet resistance during annealing according to an oxidation degree of a method of recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention according to temperature.
7 is a graph showing a sheet resistance ratio according to the number of annealing times of a method for recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention.
8 is a graph showing the overall sheet resistance ratio according to the time and temperature annealing frequency of a method for recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention.
9 is a table showing the bonding state of functional groups through oxidation and reduction of a method for improving electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention.
10 is a graph comparing the oxidation degree of maxine film to which hydrogen annealing is applied and non-applied in a method of recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention.
FIG. 11 is an enlarged photograph of a maxine film to which a hydrogen annealing is applied and not applied to a method of restoring electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention.
12 is a graph showing the relationship between Counts / s of Titanium Dioxide and Binding Energy by high temperature annealing of a method of recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention.
13 is a graph showing the relationship between temperature and time and sheet resistance ratio through annealing of an oxidized maxine film in a method of recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention.
14 is a view showing the contact angle of moisture when exposing the maxine film, which has not been annealed and the annealing process, to a high humidity in a method of recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention. It is a graph showing the relationship.
Figure 15 shows the difference between the electrical properties and heater properties of the oxidized maxine film and the oxidized maxine film and the annealed maxine film of the method for recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention. It is a graph shown.
FIG. 16 is a diagram illustrating heater characteristics according to voltages of an oxidized maxine film and an oxidized maxine film and an annealed maxine film in a method for recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention. It is a graph.
17 shows the relationship between the sheet resistance ratio of the non-oxidized maxine film and the oxidized maxine film and the anoxidized maxine film of the method for recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention, and a heater characteristic. It is a graph shown.
18 is a graph showing a relationship between a sheet resistance ratio and a heater characteristic of a non-oxidized maxine film and an annealing performed in a method for recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention.
19 is a graph showing the relationship between sheet resistance and heater characteristics of a maxine film without annealing and an annealing maxine film in a method of recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention. .
20 is a graph of sheet resistance of a maxine film according to a hydrogen atmosphere in a method of recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention.

Hereinafter, the present invention will be described with reference to the accompanying drawings. However, the present invention may be implemented in various different forms, and thus is not limited to the embodiments described herein. In addition, in order to clearly describe the present invention in the drawings, parts irrelevant to the description are omitted, and like reference numerals are assigned to similar parts throughout the specification.

Throughout the specification, when a part is "connected (connected, contacted, coupled)" to another part, this is not only when it is "directly connected", but also "indirectly" with another member in between. "It also includes the case where it is. Also, when a part is said to “include” a certain component, this means that other components may be further provided instead of excluding the other component unless otherwise stated.

The terms used in this specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “include” or “have” are intended to indicate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, and that one or more other features are present. It should be understood that the existence or addition possibilities of fields or numbers, steps, operations, components, parts or combinations thereof are not excluded in advance.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flowchart of a method for recovering electrical properties and improving oxidation stability of a 2D material according to an embodiment of the present invention, and FIG. 2 is a method for recovering electrical properties and improving oxidation stability of a 2D material according to an embodiment of the present invention Figure 3 is a cross-sectional view of the vacuum equipment is a maxine film is disposed, Figure 3 is a graph showing the sheet resistance ratio according to the change in temperature of the electrical properties recovery and oxidation stability improvement method according to an embodiment of the present invention, 4 is a graph showing a sheet resistance ratio according to a change in time in a method of recovering electrical properties and improving oxidation stability of a 2D material according to an embodiment of the present invention, and FIG. 5 is a 2D material according to an embodiment of the present invention It is a graph showing the recovery rate of the sheet resistance according to the degree of oxidation of the method of improving the electrical properties and improving the oxidation stability, and FIG. 6 is the electrical properties of the two-dimensional material according to an embodiment of the present invention A graph showing the change in sheet resistance during annealing according to the degree of oxidation of the method of improving recovery and oxidation stability according to temperature, and FIG. 7 is an annealing method of recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention 8 is a graph showing the sheet resistance ratio according to the number of times, and FIG. 8 is a graph showing the total sheet resistance ratio according to the time and temperature annealing times of the method for improving electrical properties and improving oxidation stability of a 2D material according to an embodiment of the present invention. , Figure 9 is a table showing the bonding state of the functional groups through the oxidation and reduction of the electrical property recovery and oxidation stability improvement method of a two-dimensional material according to an embodiment of the present invention, Figure 10 is an embodiment of the present invention It is a graph comparing the oxidation degree of maxine film with and without applying hydrogen annealing in a method of restoring electrical properties and improving oxidation stability of a two-dimensional material. 11 is a close-up picture of the electrical properties and film recovery of the hydrogen annealing of improved oxidative stability method is applied, and non-application of the two-dimensional Maxine material according to an embodiment of the present invention by a scanning electron microscope.

1 to 11, a method for recovering electrical properties and improving oxidative stability of a two-dimensional material according to the present invention includes (a) preparing a maxine solution composed of a two-dimensional transition metal carbide and a transition metal carbonitride, ( b) forming the prepared maxine solution into a maxine film composed of a composite material in the form of a film;

(c) storing the formed maxine film at room temperature, (d) placing it in a vacuum device to use the oxidized maxine film through storage at room temperature, and (e) hydrogen in the vacuum device in which the maxine film is placed. It provides a step of injecting gas and (f) annealing the maxine film to reduce the sheet resistance value of the maxine film exposed to the injected hydrogen gas.

In an embodiment of the present invention, a method of restoring electrical properties and improving oxidation stability of a two-dimensional material includes preparing a maxine solution composed of a transition metal carbide and a transition metal carbonitride of a two-dimensional structure (S110).

More specifically, the maxin solution is a two-dimensional layered structure, and a layer composed of atoms is stacked to form a multi-layer structure. The two-dimensional multilayer structure, maxin solution, is light and has low density, has excellent electrical conductivity, and can be easily separated from each other, and thus can be used as a radio wave absorber in various fields.

And forming a maxine solution composed of a transition metal carbide and a transition metal carbonitride having a two-dimensional structure into a maxine film composed of a composite material in the form of a film (S120).

More specifically, the prepared maxine solution is prepared in a film form through spin coating, drop cast, and vacuum filtration to prepare a maxine film, and spin coating as described above, By manufacturing the maxin film through various methods such as drop-casting and decompression filtration, the maxin film can be effectively produced according to manufacturing conditions or conditions.

In addition, the step of storing the formed maxine film at room temperature (S130).

More specifically, when the maxine film formed through the maxine solution is not in use, it may be stored at room temperature, and the maxine film is exposed to air and moisture to cause an oxidation reaction, thereby reducing surface resistance and electrical properties.

In addition, the step (S140) of placing in a vacuum equipment to use the oxidized oxidized film through normal temperature storage.

More specifically, since the electrical properties of the oxidized film oxidized through the storage at room temperature are reduced, it is placed in a vacuum device having a vacuum inside to restore it.

In addition, the step of injecting hydrogen gas into the vacuum equipment is placed maxine film (S150).

More specifically, the oxidized maxine film is reduced by exposing the maxine film to hydrogen gas. Therefore, the oxidized maxine film can be restored to a state before oxidation of electrical properties and sheet resistance values through a reduction process.

That is, the hydrogen gas is stored at room temperature, and oxygen and hydrogen gas are combined in the oxidized maxine film, and hydrogen gas is injected into the vacuum equipment to perform the reduction process of the maxine film.

Therefore, the hydrogen gas can reduce the oxidation degree of the maxine film and restore electrical properties.

In addition, an annealing step (S160) of the maxine film to restore the electrical properties of the maxine film exposed to the injected hydrogen gas.

In more detail, the maxine film is provided in the vacuum equipment to be exposed to hydrogen gas, and the vacuum equipment heats the inside to anneal the maxine film. Therefore, since the maxine film is heated to a high temperature in a state exposed to hydrogen gas, the original electrical properties can be restored through a reduction process in an oxidized state through storage at room temperature.

In addition, in the step (S160) of annealing the maxine film, it is annealed for a predetermined temperature and time.

In more detail, the maxine film can be annealed for a predetermined temperature and time to recover the original electrical properties through a reduction process. The predetermined temperature and time is not particularly limited as long as the maxine film can restore its original electrical properties, but is preferably annealed for 20 to 40 minutes at a temperature of 800 ° C to 1000 ° C.

When annealed at a temperature of less than 800 ° C or less than 20 minutes, the electrical properties cannot be restored to the original level, and when annealed at a temperature greater than 1000 ° C or for more than 40 minutes, the working time is increased, and rather the electrical properties are increased. Will decrease.

In addition, in the step (S160) of annealing the maxine film, the sheet resistance value of the maxine film annealed for a predetermined temperature and time and the sheet resistance value of the initial state maxine film before oxidation have a predetermined ratio.

More specifically, the maxine film is stored at room temperature and oxidized due to oxygen and moisture to reduce electrical properties, and can be reduced through an annealing process to restore the original electrical properties. Accordingly, the maxine film is annealed at a temperature of 800 ° C to 1000 ° C for a time of 20 minutes to 40 minutes, so that the sheet resistance value of the maxine film annealed through step (f) and the sheet resistance of the maxine film formed through step (b). The ratio of values has a ratio of 0.9 to 1.2.

In addition, various functional groups such as -O, -OH, and -F are bonded to the surface of the maxine film, and the proportion of fluorine bound to the surface is reduced through an oxidation process.

In addition, the maxin solution is Ti ₂ C, Ti ₃ C ₂ , V ₂ C, Nb ₂ C, (Ti _0.5 , Nb _0.5 ) ₂ CT _x , Ti ₃ CN, (V _0.5 , Cr _0.5 ) ₃ C ₂ , Ta ₄ C ₃ And Nb ₄ C ₃ .

In addition, the maxin solution may be of the formula M _n + ₁ X _{n, in} the formula of M _n + ₁ X _n , M is an early transition metal, and X is at least one of carbon and nitrogen. And n may be an integer from 1 to 4.

On the other hand, the vacuum equipment is a hollow body portion formed in a cylindrical shape, the inside of the body portion is a quartz tube provided so that the maxine film is disposed on the top, the maxine film disposed on the top of the quartz tube is exposed to the hydrogen gas At the lower end of one side of the body portion, a gas supply portion provided to supply the hydrogen gas, and the other end of the body portion so that the hydrogen gas supplied from the gas supply portion flows inside the body portion and is contacted with the maxine film and then discharged to the outside. It may include a gas discharge portion provided in the annealing portion is heated to a high temperature is disposed to surround the side wall of the body portion, the quartz tube is arranged to anneal the maxine film.

The vacuum equipment is provided with a body portion formed in a hollow cylindrical shape.

More specifically, the body portion is formed in a cylindrical shape, and is provided with a hollow so that the maxine film is disposed inside the body portion.

In addition, a quartz tube is provided inside the body so that the maxin film is disposed on the top.

More specifically, the quartz tube is a tube formed of quartz and is provided so as not to be deformed even when the body portion is heated to a high temperature, and is disposed inside the hollow body portion.

In addition, a gas supply unit is provided at one lower end of the body unit to supply the hydrogen gas.

More specifically, the gas supply unit is supplied with the hydrogen gas to the lower end of one side of the body portion so that the maxine film disposed on the upper end of the quartz tube is exposed to the hydrogen gas.

Therefore, the maxine film is in contact with the hydrogen gas supplied through the gas supply unit to perform the reduction process.

In addition, a gas discharge portion provided at the other end of the body portion is provided.

In more detail, the gas discharge portion is provided at the other end of the body portion so that the hydrogen gas supplied from the gas supply portion flows inside the body portion and is discharged to the outside after contacting the maxine film.

Therefore, the hydrogen gas supplied from the gas supply unit passes through the maxine film and is discharged to the gas discharge unit.

In addition, an annealing portion is provided to surround the side wall of the body portion on which the quartz tube is arranged to heat the body portion at a high temperature so that the maxine film is annealed. Therefore, the maxine film is heated through the annealing portion, and through the reduction process, the electrical properties of the maxine film are restored to a level before oxidation.

In addition, a pulse element may be configured as an electrode material through a stored pulse film through a method of recovering electrical properties and improving oxidation stability of the two-dimensional material.

Referring to FIG. 3, a method for recovering electrical properties and improving oxidation stability of a two-dimensional material according to the present invention was annealed at a temperature of 100 ° C. to 900 ° C. for 30 minutes. ₀ ) and the sheet resistance ratio (Rs) of the maxine film after oxidation increased to 3.19 after oxidation and decreased to 0.93 through annealing.

Therefore, the recovery of the oxidized maxine film decreases as the sheet resistance ratio increases in an annealing process at a high temperature, so that the high temperature is more effective.

Referring to FIG. 4, a method of recovering electrical properties and improving oxidation stability of a two-dimensional material according to the present invention was performed by annealing for 30 minutes or 60 minutes at a temperature of 500 ° C., which was annealed for 60 minutes at a temperature of 500 ° C. It is more effective to perform annealing for 30 minutes at a temperature of 500 ° C. than to perform.

Therefore, as the annealing time becomes longer, the sheet resistance ratio increases, so that the efficiency decreases.

Referring to FIG. 5, a method of recovering electrical properties and improving oxidation stability of a two-dimensional material according to the present invention is a graph showing a recovery rate of sheet resistance according to oxidation degree according to temperature, and a large difference in recovery rate according to oxidation degree rather than temperature have.

That is, when the annealing is performed at temperatures of 500 ° C and 900 ° C for 30 minutes depending on the degree of oxidation, the higher the degree of oxidation, the greater the recovery rate of the sheet resistance due to annealing, and the lower the oxidation rate, the lower the rate of recovery of sheet resistance due to annealing.

Referring to FIG. 6, a method for recovering electrical properties and improving oxidation stability of a two-dimensional material according to the present invention was annealed at temperatures of 500 ° C. and 900 ° C. for 30 minutes, and there is a difference in recovery rate according to the degree of oxidation.

That is, when annealing is performed under the same conditions in the case of the high-oxidation maxine film and the low-oxidation maxine film, the reduction in the sheet resistance ratio of the high-oxidation maxine film is higher than that of the low-oxidation maxine film.

Referring to FIG. 7, a method of recovering electrical properties and improving oxidation stability of a two-dimensional material according to the present invention was annealed several times for 30 minutes at a temperature of 500 ° C or 10 minutes at a temperature of 900 ° C. The initial oxidized maxine film had a reduced sheet resistance ratio, but the annealing performed several times thereafter did not decrease the sheet resistance ratio but slightly increased.

As a result, referring to FIG. 8, which summarizes the experimental data, the maxine film has excessive annealing time and repetitive annealing, thereby reducing electrical characteristics and increasing sheet resistance ratio. Therefore, performing annealing once for 20 minutes to 40 minutes at a temperature of 800 ° C to 1000 ° C can restore the electrical properties of the maxine film and reduce the sheet resistance ratio.

Referring to FIG. 9, the maxine film stored at room temperature has a number of functional groups such as -O, -OH, and -F bonded to the surface. Coarse maxine film can reduce the proportion of fluorine (-F) on the surface.

In the case of a fluorine group, the functional group is bound to the surface during acid treatment (LiF, HF) for exfoliation of maxine. Fluorine bound to the maxine surface has a work function of about 5 eV. When used as an electrode, the injection of electrons can be limited.

Therefore, during the acid treatment of the maxine film, the fluorine group among the various functional groups (-O, -OH, -F, etc.) attached to the surface is released from the surface of the maxine film through a high temperature annealing method, thereby converting the maxine film to an electrode. When used, it is possible to prevent the fluorine group from limiting electron injection.

Referring to FIG. 10, as a graph comparing the oxidation degree of the maxine film to which hydrogen annealing was applied and not applied, oxidation of the maxine film was performed in a 70 degree oven containing water vapor, and the hydrogen annealed maxine film (solid red line) After performing annealing at a temperature of 900 ° C for 30 minutes, oxidation is hardly generated even when exposed to an environment in which oxidation is promoted, but the maxine film (black solid line) without hydrogen annealing was oxidized.

That is, through hydrogen annealing, maxine film forms a solid network, and even after 60 hours of sheet resistance, the change is not large compared to the initial value, which prevents the penetration of oxygen and moisture to prevent oxidation, but hydrogen annealing The unapplied maxin film increased to 1126 times compared to the initial value after the sheet resistance had passed for 60 hours, which means that oxygen and moisture penetrated, and oxidation proceeded rapidly.

Referring to FIG. 11, the oxidizing degree was compared by expanding the maxine film to which hydrogen annealing was applied and not applied with a scanning electron microscope (SEM).

The maxine film to which hydrogen annealing has been applied (top) has a solid network formed on the surface, but the maxine film without hydrogen annealing (bottom) has been changed to porosity by surface oxidation. Therefore, the maxine film to which hydrogen annealing is applied is resistant to oxidation due to the penetration of oxygen and moisture, so that oxidation can be prevented.

12 is a graph showing the relationship between Counts / s of Titanium Dioxide and Binding Energy by high temperature annealing of a method of recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention.

Referring to FIG. 6, in the case of the oxidized maxine film as mentioned above, when annealing is performed, the sheet resistance ratio of the oxidized maxine film is recovered. Referring to FIG. 12, the recovery of the sheet resistance ratio of the oxidized maxine film is reduced by a high temperature annealing, and the peak ratio of titanium dioxide is reduced by comparing annealing (a) and annealing (b). Through the reduction of titanium, the sheet resistance ratio of the maxine film is restored.

That is, titanium dioxide is generated through the oxidation process of the maxine film, and the produced titanium dioxide is reduced through high temperature annealing with hydrogen, thereby recovering the sheet resistance ratio of the maxine film.

13 is a graph showing the relationship between temperature and time and sheet resistance ratio through annealing of an oxidized maxine film in a method of recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention.

Referring to FIG. 13, when the maxine film is exposed to an environment at 70 ° C. and 100% humidity, which is easily oxidized, and heat treatment is not performed (black line), when annealing is performed at 300 ° C. for 30 minutes (green), 500 ° C. When the experiment was performed as in the case where annealing was performed for 30 minutes (blue), and annealing was performed at 900 ° C for 30 minutes (red), when the annealing was not performed, the sheet resistance ratio increased rapidly, but the sheet resistance ratio increased as the temperature increased. Since it is kept constant, electrical characteristics can also be kept constant.

14 is a view showing the contact angle of moisture when exposing the maxine film, which has not been annealed and the annealing process, to a high humidity in a method of recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention. It is a graph showing the relationship.

Referring to FIG. 14, after exposing the maxine film (a, b) without annealing and the maxine film (c, d) with annealing to an environment having a humidity of 100%, moisture is passed after 1 minute (b, d). When measuring the contact angle of the, the maxin film without annealing initially has a contact angle of 44 degrees with the water droplet, and then the moisture rapidly permeates into the inside, and the contact angle with the droplet decreases by 10 degrees, and with hydrogen at 900 ℃. In the case of the maxine film in which annealing has been performed, the contact angle with the water droplets is maintained at 42 degrees after 1 minute from the beginning.

That is, by performing annealing with hydrogen, a solid network is formed on the surface of the maxine film to change from a porous structure to a structure in which pores have disappeared before performing annealing, thereby preventing the penetration of moisture and oxygen. .

Figure 15 shows the difference between the electrical properties and heater properties of the oxidized maxine film and the oxidized maxine film and the annealed maxine film of the method for recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention. It is a graph shown.

Referring to FIG. 15, the electrical properties and heater characteristics according to the temperature and time of the oxidized maxine film (a), the oxidized maxine film (b), and the maxine film (c) subjected to annealing in a hydrogen atmosphere are maxima films. When oxidized (b) is reduced, in the case of maxine film (c), which has been re-annealed to a hydrogen atmosphere and 900 ° C, electrical and heater properties are restored.

Accordingly, by performing annealing of the oxidized maxine film in a hydrogen atmosphere, electrical characteristics and heater characteristics can be restored.

FIG. 16 is a diagram illustrating heater characteristics according to voltages of an oxidized maxine film and an oxidized maxine film and an annealed maxine film in a method for recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention. It is a graph.

Referring to FIG. 16, the oxidized maxine film and the oxidized maxine film and the annealed maxine film change heater characteristics according to voltages (10V, 15V, 20V, and 25V). In the case of oxidized maxine film, heater characteristics It is reduced than the non-oxidized maxine film.

At this time, when annealing the oxidized maxine film in a hydrogen atmosphere at 900 ° C, the heater characteristics are increased again.

17 shows the relationship between the sheet resistance ratio of the non-oxidized maxine film and the oxidized maxine film and the anoxidized maxine film of the method for recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention, and a heater characteristic. It is a graph shown.

Referring to FIG. 17, the sheet resistance ratio of the non-oxidized maxine film is 65.3 ohm / sq, and when the sheet resistance ratio is increased to 95.5 ohm / sq by oxidizing it, the heater characteristic is reduced.

At this time, when annealing the oxidized maxine film in a hydrogen atmosphere, the sheet resistance ratio is reduced to 68.5 ohm / sq, and the heater characteristics are also increased.

In addition, when the oxidized maxine film is oxidized to a high value and the sheet resistance ratio is increased to 990.1 ohm / sq and the heater characteristics are reduced, by performing annealing the oxidized maxine film in a hydrogen atmosphere, the sheet resistance ratio is reduced to a certain level and the heater Traits can also be restored.

Therefore, the oxidized maxine film can recover sheet resistance ratio and heater characteristics by performing annealing in a hydrogen atmosphere.

18 is a graph showing a relationship between a sheet resistance ratio and a heater characteristic of a non-oxidized maxine film and an annealing performed in a method for recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention.

Referring to FIG. 18, even if the unoxidized maxine film and the annealing-executed maxine film at 900 ° C. and a hydrogen atmosphere have the same similar sheet resistance, or the annealed maxine film has a higher sheet resistance than the unoxidized maxine film The maxine film, which is annealed in the atmosphere, exhibits higher heater characteristics.

19 is a graph showing the relationship between sheet resistance and heater characteristics of a maxine film without annealing and an annealing maxine film in a method of recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention. .

Referring to FIG. 19, when an annealing-free maxin film (a, b) and an annealing maxin film (c, d) are exposed to an environment at 70 ° C. and humidity of 100% for 24 hours (b, d), , Maxine film (b) without annealing was significantly increased in sheet resistance, but maxine film (d) with annealing was not significantly increased, and maxine film (b) without annealing was significantly reduced in heater properties. However, the maxine film (d) subjected to annealing did not significantly reduce the heater characteristics.

In addition, when looking at the color change according to the temperature, the maxine film (a, b) that has not been annealed is exposed to the environment at 70 ° C. and 100% humidity for 24 hours, and the color has changed as the temperature decreases, but annealing is performed. The maxine film (c, d) is not changed in color even after exposure to 70 ° C. and 100% humidity for 24 hours.

Therefore, by performing annealing on the maxine film in a hydrogen atmosphere, the sheet resistance and heater characteristics can be kept constant, and by performing annealing on the maxine film in the hydrogen atmosphere, the sheet resistance and heater characteristics can be restored to a certain level. You can.

20 is a graph of sheet resistance of a maxine film according to a hydrogen atmosphere in a method of recovering electrical properties and improving oxidation stability of a two-dimensional material according to an embodiment of the present invention.

Referring to FIG. 20, when annealing is performed in a hydrogen atmosphere or in a hydrogen-free condition, an oxidized maxine film and an oxidized maxine film are annealed in a hydrogen atmosphere. It shows a higher value of sheet resistance than maxin film. Therefore, when the annealing is performed in a hydrogen atmosphere when the sheet resistance is increased due to oxidation of the maxine film, the effect of restoring the sheet resistance becomes greater.

In addition, when annealing a non-oxidized maxine film in a hydrogen atmosphere or in a hydrogen-free condition, even when annealing is performed in a hydrogen-free condition, the sheet resistance is maintained lower than that in an annealing-free maxin film, but in a hydrogen atmosphere When annealing is performed, a lower sheet resistance can be maintained.

Therefore, a predetermined oxidation resistance is generated by performing annealing, but it is possible to have a higher oxidation resistance by performing annealing in a hydrogen atmosphere.

The above description of the present invention is for illustration only, and those skilled in the art to which the present invention pertains can understand that it can be easily modified to other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts should be interpreted to be included in the scope of the present invention.

Claims (13)

(a) preparing a maxine solution composed of a two-dimensional transition metal carbide and a transition metal carbonitride;
(b) forming the prepared maxine solution into a maxine film composed of a composite material in the form of a film;
(c) storing the formed maxine film at room temperature;
(d) placing in a vacuum equipment to use the oxidized maxine film through the storage at room temperature;
(e) injecting hydrogen gas into the vacuum equipment in which the maxine film is disposed; And
(f) annealing the maxine film to restore the electrical properties of the maxine film exposed to the injected hydrogen gas to a level before oxidation;
Method for improving electrical properties and improving oxidation stability of a two-dimensional material comprising a. According to claim 1, wherein the maxin solution is Ti ₂ C, Ti ₃ C ₂ , V ₂ C, Nb ₂ C, (Ti _0.5 , Nb _0.5 ) ₂ CT _x , Ti ₃ CN, (V _0.5 , Cr _0.5 ) ₃ C ₂ , Ta ₄ C ₃ And Nb ₄ C ₃ A method of restoring electrical properties and improving oxidation stability of 2D materials. [3] The method of claim 2, wherein the maxine solution is composed of the formula M _n + ₁ X _n . [4] The method of claim 3, wherein M in the formula of M _n + ₁ X _n is a lead transition metal. The method of claim 4, wherein X in the formula of M _n + ₁ X _n includes at least one of carbon and nitrogen. According to claim 5, In step (b),
The maxin solution is a method of recovering electrical properties and improving oxidation stability of a two-dimensional material, characterized in that it is manufactured in a film form through spin coating, drop casting, and vacuum filtration. The method of claim 6, wherein in step (f),
The maxine film is a method for improving the electrical properties and improving the oxidation stability of a two-dimensional material, characterized in that it is annealed for 20 minutes to 40 minutes at a temperature of 800 ° C to 1000 ° C. The two-dimensional material according to claim 7, wherein the ratio of the sheet resistance value of the maxine film annealed through the step (f) and the sheet resistance value formed through the step (b) has a ratio of 0.9 to 1.2. To improve electrical properties and improve oxidation stability. 9. The method of claim 8, wherein the functional group bound to the surface of the maxine film is reduced in proportion to fluorine through oxidation and reduction. 10. The method of claim 9, wherein the maxine film forms a solid network on the surface through annealing to prevent oxidation under the membrane by preventing penetration of oxygen and moisture. 11. The method of claim 10, wherein the maxine film is subjected to annealing for 30 minutes at a temperature of 900 ℃ to improve the electrical properties and oxidation stability of the two-dimensional material characterized in that the surface resistance value is maintained 3.1 times or less compared to the initial value Way. The method of claim 11, wherein the vacuum equipment,
A body portion formed in a hollow cylindrical shape;
A quartz tube provided so that the maxine film is disposed on the inside of the body part;
A gas supply unit provided to supply the hydrogen gas to one lower end of the body portion so that the maxine film disposed on the upper end of the quartz tube is exposed to the hydrogen gas;
A gas discharge portion provided at the other end of the body portion so that the hydrogen gas supplied from the gas supply portion flows inside the body portion and is discharged to the outside after being in contact with the maxine film; And
An annealing part arranged to surround the side wall of the body part on which the quartz tube is arranged so that the maxine film is annealed and heated to a high temperature;
Method for recovering the electrical properties and improving the oxidation stability of the two-dimensional material comprising a. According to claim 1 to claim 12, Maxine device, characterized in that consisting of an electrode material through a maxine film formed through a method for improving the electrical properties and oxidation stability of the two-dimensional material.

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