KR20190104095A - Method for Manufacturing Conductive Layer consisted of Metallic Clusters onto Substratea - Google Patents

Abstract

The present invention relates to a method for manufacturing a conductive film with excellent electromagnetic shielding efficiency by forming the conductive film consisting of metallic cluster layers on a substrate of various materials such as metal, paper, plastic, and carbon materials. More specifically, the present invention relates to the method for manufacturing a conductive film consisting of metallic cluster layers by a deposition process comprising the following steps: (A) coating a metal precursor solution on a surface of a substrate to form a metal precursor coating layer; (B) drying the metal precursor coating layer during a predetermined time to induce supersaturation of the solution; and (C) treating the supersaturated metal precursor coating layer with plasma to form a metal cluster layer.

Description

Method for Manufacturing Conductive Layer consisted of Metallic Clusters onto Substratea}

The present invention relates to a method for manufacturing a conductive film on a substrate of various materials such as metal, paper, plastic, carbon material, more specifically, by forming a conductive film consisting of a metal cluster layer on the substrate as described above It is related with the manufacturing method of this excellent electrically conductive film.

With the recent increase in the use of various electrical equipment and electronic application equipment, interest in electromagnetic waves is also increasing. Electromagnetic waves are classified into radio waves (long wave, medium wave, short wave, microwave, microwave, microwave), infrared ray, visible ray, ultraviolet ray, X ray, gamma ray in order of low frequency according to frequency.

On the other hand, it is already widely known that the danger of radiation such as X-rays and gamma rays with strong energy, and ultraviolet rays cause various diseases such as skin cancer. The recent controversy of electromagnetic hazards is the 'extremely low frequency' (ELF) generated from transmission and distribution lines and home appliances, and the 'high frequency' in radio frequency due to the increase in the use of mobile communication terminals and base station facilities. Frequency: RF). Electromagnetic waves are also known to induce malfunctions and disturbances of various electrical and electronic devices. With the emphasis on the harmfulness of electromagnetic waves, the UN Agency for International Cancer Research in 1999 defined electromagnetic waves as a "carcinogenic substance", a class 2 carcinogen.

Despite the above hazards, various electronic / electrical devices (various electronic / electrical devices including white appliances, smart phones, and electric vehicles), which are the main causes of the emission of electromagnetic waves, provide convenience to human life. The situation is increasing rapidly. Therefore, there is an urgent need to develop a technology capable of shielding the emission of electromagnetic waves in various electronic / electrical devices, as well as a technology capable of shielding the inflow of electromagnetic waves from the outside.

The shielding of the electromagnetic waves may be possible by forming a conductive film on the case of the component or the whole device that generates electromagnetic waves of the electronic / electrical device. In addition, the conductive film may be used in various fields such as manufacturing printed circuit boards, forming and packaging circuits of semiconductors, manufacturing various types of electrodes and antistatic plates, and shielding agents according to electrical conductivity. Hereinafter, a method of manufacturing a conductive film will be described based on the conventional art.

First, the manufacturing method of the conductive film can be largely divided into dry plating and wet plating.

Dry plating is a method of depositing a metal on a surface in a vacuum, such as vacuum deposition such as sputtering. The vacuum deposition method has the advantage that it is possible to form a conductive film on the surface of a non-conductor such as plastic, and to easily form the thickness of the conductive film to be formed. However, since the plating film formed by evaporation has poor abrasion resistance, and the evaporated metal is condensed on the surface after evaporation of the metal to form a thin film, the degree of vacuum must be kept high, which is expensive and forms a conductive film uniformly in a large area. There is a problem that it is difficult.

The wet plating method is an electroplating method, an electroless plating method, or a conductive paste (paint) coating method in which a paint or paste containing metal powder is coated on a coated object. Among them, the electroplating method can not be used to form a conductive film on the surface of the insulator, so its application is extremely limited. The electroless plating method requires pretreatment of the substrate by a complex process so that a reduction reaction can occur on the surface of the substrate (registered patent 10-1371088, published patent 10-2004-0015090), or use a special kind of material. In addition, environmental problems caused by the waste liquid are inevitable. The method of manufacturing a conductive film using conductive paint or paste has little influence on the material of the substrate, and the adhesion of the paint or paste is also good. However, in order to enhance adhesion, a high temperature heat treatment is required in the process of treating the substrate with plasma or baking the paint or paste, and most conductive paints and pastes are imported and have a high price. In addition, compared with the dry deposition method or the plating method, the thickness of the conductive film is not easy to control, and thus the conductivity of the formed conductive film is not easy to control.

As such, although the conductive film, particularly the conductive film formed on the surface of the polymer material, may be usefully used for various purposes such as electromagnetic shielding in electronic device components, its application is limited due to the above problems.

Therefore, while maintaining the advantages of dry deposition method that is easy to control the thickness of the conductive film irrespective of the material of the base material, it does not require expensive equipment, and large-area by a simple process under low temperature conditions that do not cause deformation of the atmospheric pressure and the base material There is a demand for the development of a new method capable of forming a conductive film having excellent adhesion to a substrate.

Patent 10-1371088 Patent Publication 10-2004-0015090 Patent Registration 10-1355726

SUMMARY OF THE INVENTION The present invention has a first object to provide a method for producing a large-area conductive film relatively easily on the surface of a substrate even with a simple process utilizing plasma.

In addition, a second object is to provide a method for easily forming a conductive film having a low cost and a desired range of sheet resistance in a large area without using expensive vacuum equipment or expensive raw materials.

In addition, it is possible to easily form a large-area conductive film on substrates of various materials such as metal, glass, polymer resin, paper, carbon nanotube, graphene and graphite, and unlike the prior art, it does not generate wastewater. A third purpose is to provide a method for forming a large-area conductive film in a wide range while being environmentally friendly.

In addition, a fourth object is to provide an electromagnetic wave shielding agent using the conductive film formed by the above method.

Hereinafter, a solution for achieving the object of the present invention will be described.

In order to achieve the above object, the present invention comprises the steps of (A) coating a metal precursor solution on the surface of the substrate of any material to form a metal precursor coating layer; (B) drying the metal precursor coating layer for a predetermined time to induce supersaturation of the solution; And (C) treating the supersaturated metal precursor coating layer with plasma to form a metal cluster layer. The present invention relates to a conductive film manufacturing method comprising a metal cluster layer by a deposition process. Of course, the step of washing and drying the conductive film prepared after the step (C) may be added. The metal precursor is reduced to metal by plasma treatment to form a cluster layer.

In the present invention, the '(one) cluster layer' may be irregularly entangled with metal nanoparticle aggregates of various sizes and roughly cocoon shapes, ranging from tens to hundreds of nm, as shown in the electron micrograph illustrated in FIG. 9. It means the layer with many voids of several hundred-several micrometers thick which were three-dimensionally formed three-dimensionally.

In the present invention, in order to increase the conductivity of the conductive film, the deposition process including the steps (A) to (C) may be repeated 3 to 15 times. The three-dimensional metal cluster layer is deposited (formed) on the substrate by the deposition process, and the repetition frequency of the deposition process is defined as the deposition frequency below. In this case, the repetition of the deposition process is to further deposit the metal cluster layer on the upper surface of the metal cluster layer on the substrate formed in the previous deposition process.

For example, in the case of the conductive film produced by performing the deposition process 1 to 2 times according to the present invention, the sheet resistance is not only higher than several hundreds of kPa / sq, depending on the concentration of the precursor solution used and the type of metal. According to the measurement position in the formed conductive film, a large difference in sheet resistance value may result in low uniformity of the conductive film. When the number of depositions was three or more times, the sheet resistance was not only rapidly decreased, but also the uniformity of the formed conductive film was excellent. Although the number of deposition times exceeds 15 times, it does not become a problem, but considering the economical efficiency of the process, it was preferable that it is 15 times or less.

In the present invention, the substrate may be used as long as the material is not deformed by the solvent constituting the metal precursor solution, and examples thereof include metals, metal oxides, ceramics, polymer resins, glass, and carbon materials. Examples of the carbon material may include carbon nanotubes, graphene or graphite. In addition, the present invention, as can be seen in the following examples, there is no process requiring a high temperature, it is possible to form a conductive film on a substrate that is weak to heat, such as paper or polymer resin. In addition, even when the substrate is an insulator to which the electroplating method cannot be applied, the method of the present invention may be more usefully applied.

The metal precursor solution is prepared by dissolving a metal precursor in a solvent.

The metal precursor may be any metal precursor containing a noble metal or a transition metal, and may be tetrachloroplatinate, potassium hexachloroplatinate, potassium tetrachloroplatinate, tetrachlorogold (III) acid tetrahydrate. , Palladium chloride, silver nitrate, chloroplatinic acid, hexachloroplatinum (IV) acid, chloroplatinic acid hexahydrate, chloroplatinic acid hydrate, gold chloride, gold chloride trihydrate, palladium chloride (II), tetraminpalladium (II) nitrate and their Any one selected from the group of mixtures may be exemplified, but is not limited thereto.

The solvent used in the preparation of the solution is not limited to the kind as long as it can dissolve the metal precursor, but is preferably non-toxic in consideration of process safety. Examples of the solvent include, but are not limited to, water or C1 to C5 alcohols or diols, or mixtures thereof.

It is preferable that the density | concentration of the said metal precursor is 0.1-1.0M. Even when the concentration of the precursor is less than 0.1M, the conductive film is not formed, but the sheet resistance varies greatly depending on the measurement position, thereby confirming that the conductive film is not formed uniformly.In addition, the application of the conductive film such as a printed circuit or a shielding agent Regarding the formation of a conductive film that provides a sheet resistance that is equivalent to, a precursor solution of 0.1 M or less requires more deposition times than a precursor solution of 0.1 M or more, resulting in an economical process. Inefficient On the other hand, when the concentration of the precursor is higher than 1.0M, not only precipitation occurs but also a conductive film is not formed in a uniform thickness.

The coating of the metal precursor solution of step (A) may be applied by selecting an appropriate one from a known coating method, and the specific method is not limited.

In the step (B), a part of the solvent is removed so that the solution of the metal precursor coating layer is in an appropriate supersaturated state. The degree of drying to induce the 'supersaturated state' will vary depending on the type of precursor and solvent, the concentration of the precursor solution, and the amount coated on the substrate. Specific examples can be found in the examples.

Preliminary experiments have shown that the amount of coating liquid applied to a particular substrate (without overflowing), regardless of the concentration of the precursor solution, is limited, and if the coating liquid is excessive, the solvent evaporates during the plasma treatment, which prevents stable and uniform treatment of the plasma. It was.

On the other hand, when the solvent of the coating liquid is almost or completely evaporated, the sheet resistance increases and the electromagnetic wave shielding efficiency is reduced, so that the utility as the conductive film, the electromagnetic shielding film or the shielding agent is very low. In addition, in the case of plasma treatment of the solvent in the coating liquid almost or completely evaporated, the cluster layer is not formed, but metal nanoparticles having a diameter of 2-4 nm or aggregates of metal nanoparticles having a size of 10-20 μm are flat on the surface of the substrate. It is sparsely formed on the surface of the substrate in the form of dots. In this regard, the present inventors have been filed as a "Method for Producing Metal Nanoparticles Attached on the Surface of a Substrate Using Plasma" and registered under Patent No. 10-1355726 (Reference Invention).

The other conditions are the same, and the reason why the cluster layer is formed (the present invention) or the metal nanoparticle dots are formed (reference invention) due to the difference in the degree of drying of the solvent of the coating liquid during plasma treatment is another research subject to be solved later. However, the following inference is possible.

① Cluster layer formation

The solvent layer remaining after the coating liquid coated on the substrate is partially dried becomes a space in which the supersaturated precursor particles move in three dimensions. At this time, when the plasma is treated, unstable supersaturated precursor particles move freely in a three-dimensional space (some remaining solvent layers) to form aggregates. Gradually, when the solvent layer is removed, aggregates adhere to the substrate to form a steric, porosity cluster layer.

② Nanoparticle Formation

When the solvent in the coating liquid is excessively dried, the three-dimensional movement of the precursor particles is very limited because there is almost no solvent layer. At this time, the plasma treatment prevents the precursor particles from agglomerating to form nanoparticles on the surface of the substrate, or even form a dot on the surface of the substrate.

In the present invention, the plasma treatment is possible under normal pressure, as shown in the following examples. The use of atmospheric pressure plasma eliminates the need for ancillary equipment to maintain a vacuum, which makes it possible to manufacture a conductive film in a very simple process.

The plasma is not limited thereto as long as it can be generated using a direct current or alternating voltage, and examples thereof include an AC radio wave or a microwave plasma, and may be treated with a power of 1 to 1000 W. In addition, the plasma treatment time can be appropriately adjusted in consideration of the power of the plasma, and if the plasma power is too low or the treatment time is too short, the reduction to the metal particles does not occur sufficiently, so that even if the increase in the deposition frequency increases the desired degree of conductivity. It is difficult to represent. On the other hand, if the power of the plasma is too high or the processing time is too long, the temperature of the substrate may rise excessively, and the formed conductive film may not be uniformly formed. The quality of the plasma can be appropriately adjusted by the usual plasma processing conditions such as the type of carrier gas, flow rate, and processing temperature. However, the plasma treatment temperature was more preferably less than 100 ° C. When the plasma treatment temperature was too high, it was difficult to maintain the uniformity of the conductive film formed as well as to cause deformation of the substrate when using a polymer resin or paper substrate.

Even when the plasma is processed at room temperature, the temperature of the substrate may increase as the plasma processing time increases. Increasing the temperature not only causes deformation of the substrate when using a substrate that is weak in heat, but also adversely affects the uniformity of the conductive film, so that the substrate is subjected to 0.001 to 100 mm / in the plasma treatment step of (C). It is preferable to reciprocate back and forth at a linear speed of sec. The moving speed of the substrate may be appropriately adjusted according to the processing conditions of the plasma such as power or processing time of the plasma.

In addition, before the coating of the precursor solution in step (A), the surface of the substrate may be further subjected to a pretreatment for 0.1 to 15 minutes using an atmospheric pressure plasma. According to the pretreatment step, the adhesion between the metal particles reduced in step (C) and the substrate may be enhanced.

According to the conductive film production method according to the present invention as described above, it was easy to control to have a sheet resistance in a desired range by adjusting the concentration of the metal precursor solution, the degree of drying the coating solution, the plasma treatment conditions, the number of depositions and the like. In addition, since it can be manufactured at normal pressure, a uniform conductive film can be formed regardless of the type of substrate without using expensive raw materials or equipment.

The conductive film formed by the method of the present invention can be used for various purposes such as manufacturing printed circuit boards, forming and packaging circuits of semiconductors, various types of electrodes and antistatic plates, and shielding agents.

As described above, according to the present invention, the conductive film can be easily formed in a large area at room temperature and atmospheric pressure even without expensive equipment required for high vacuum or high temperature.

In addition, the conductive film can be formed on a non-conductive substrate such as glass, polymer resin, or paper without forming the conductive film. In addition, since the temperature is low when the conductive film is formed, the substrate is made of polymer resin or paper. Even in this case, the conductive film can be formed without causing deformation of the substrate.

In addition, the conductive film manufacturing method of the present invention is an environmentally friendly method that does not cause an environmental problem due to the waste liquid because the conductive film is formed using only a minimum solvent for coating the metal precursor solution.

In addition, since the conductive film formed by the method of the present invention can easily control the sheet resistance of the formed conductive film, it is suitable for various fields such as manufacturing printed circuit boards, forming and packaging semiconductors, various types of electrodes, antistatic plates, shielding agents, and the like. It is widely applicable.

1 is a drying curve of the coating liquid used in the present invention.
2 is a graph showing the effect of the drying time of the precursor coating layer on the sheet resistance of the conductive film.
3 is a graph showing the electromagnetic shielding rate of the conductive film according to the drying time of the precursor coating layer.
Figure 4 is a graph showing the sheet resistance according to the number of deposition of the conductive film formed using 0.1M AgNO ₃ solution.
Figure 5 is a graph showing the sheet resistance according to the number of deposition of the conductive film formed using H ₂ PtCl ₆ · xH ₂ O solution.
Figure 6 is a graph showing the sheet resistance according to the number of deposition of the conductive film formed using HAuCl ₄ solution.
Figure 7 is a graph comparing the sheet resistance of the conductive film formed by each metal precursor at the same number of deposition.
Figure 8 is a conductive film appearance photo according to the number of deposition in the manufacturing method according to the present invention.
9 is a SEM image of the surface and the vertical cut surface of the conductive film prepared in an embodiment of the present invention.
10 is a graph showing the effect of the concentration of the precursor solution on the sheet resistance of the conductive film.
11 is a graph of sheet resistance of conductive films according to precursor solution concentrations.
12 is a graph showing the electromagnetic shielding rate of the conductive film according to the concentration of the precursor solution.
13 is a graph showing the effect of atmospheric pressure plasma treatment time of the dried precursor coating layer on the sheet resistance of the conductive film.
14 is a graph showing the electromagnetic shielding rate of the conductive film according to the plasma treatment time of the dried precursor coating layer.

The present invention will be described in more detail with reference to the following Examples.

EXAMPLE

Example 1: basic manufacturing method and conductive film characteristics analysis

(1) Preparation of conductive film

Of water and ethanol 1: 3 (v / v) a 0.1 ~ 1.0M AgNO ₃ solution and 0.1 ~ 1.0MH prepared using a 0.1 ~ 1.0M AgNO ₃ solution was prepared by using isopropanol or a mixture and ₂ PtCl ₆ xH ₂ The O solution was drop coated onto 1 × 1 cm 2 of PET substrate by 2.0 μl per 1 × 1 cm 2 of substrate. Thereafter, the solvent was partially or completely removed by drying at 70 ° C. for 0.5-10 minutes. The coated substrate was reduced to a plasma atmosphere (Ar, 150 W, 5 lpm) for 5-8 minutes while moving at a forward and backward reciprocating speed of 5 mm / sec. In more detail, the substrate to be reciprocated back and forth by the stepping motor is located in the lower portion, the atmospheric pressure plasma generator is located in the upper portion, the plasma is irradiated from the upper portion to the lower portion, the distance between the atmospheric pressure plasma and the substrate is Fixed to 2.5 mm. After the formation of the conductive film, the substrate was ultrasonically washed with ethanol to remove impurities, further washed with distilled water, and dried by nitrogen blowing. The repetition frequency of the coating-plasma treatment-cleaning and drying process of the metal precursor was defined as the deposition frequency, and the conductive film was formed by varying the deposition frequency.

(2) conductive film characteristics analysis

① Sheet resistance measurement

The conductive film formed on the dried substrate was subjected to the 4-probe method using a sheet resistance meter (CMT Series). The sheet resistance was expressed as an average value by measuring the surface resistance at three arbitrary points on the substrate.

② Measurement of electromagnetic shielding efficiency

The electromagnetic wave shielding rate was measured using the VNA master (MS2024B, Anritsu) which is an electromagnetic wave measuring apparatus with respect to the sample cut | disconnected the prepared conductive film (including a base material) in the shape of the circular disk of diameter 5cm.

Confirmation Experiment: Drying Characteristics of Coating Liquid

Water and ethanol 1: After 3 (v / v) drop in a 0.5 M AgNO ₃ solution 50.0 ㎕ [AgNO ₃ from about 2.13 mg] a 5 × 5 ㎠ PET substrate prepared by using the mixture coated, 0 and at 70 ℃ The degree of drying of the coating solution was measured at 2 minute intervals for 20 minutes. As a result, after about 6 minutes, it seems to have been 'dried' to the naked eye, and as can be seen in FIG.

Example 2 Characteristics of the Conductive Film According to the Precursor Coating Film Drying Time

A 1 M AgNO ₃ solution was used, and drying time was varied at a drying temperature of 70 ° C., and a conductive film was prepared under the condition of 5 times of deposition and 7 minutes of plasma treatment.

(1) Sheet resistance characteristics

The sheet resistance of the conductive film was largely increased as the drying time of the precursor coating was increased (FIG. 2). Another thing to note is that as the drying time increases, the deviation according to the measuring position, ie the standard error, increases. This is understood to be a phenomenon in which the uniformity of the conductive film is reduced because the free movement of the precursor is limited when the coating liquid is excessively dried, as in the following examples, in which the sheet resistance and the variation are increased at high concentrations. In the supersaturated state in which the precursor solution is not completely dried, the precursor is uniformly dispersed and reduced by plasma, so that a more uniform conductive film can be formed and the variation in sheet resistance according to the position can be understood.

(2) electromagnetic shielding characteristics

3 shows the electromagnetic shielding efficiency of the conductive film depending on the drying time.

As can be seen in the figure showed the highest shielding rate characteristics at 2.5 to 5 minutes of drying. When less than 2.5 minutes (eg 1.5 minutes) of drying, the coating liquid does not reach the supersaturated state and the collision (contact) frequency of the metal precursor particles for coagulation is low. It is estimated that the electromagnetic shielding efficiency decreases because free movement of the precursor or precursor aggregate is limited.

The results of (1) and (2) above show that the sheet resistance properties are high when the metal precursor solution is supersaturated and a significant amount of solvent remains so that the precursor particles can be frequently collided (contacted) while freely moving the solvent layer. This shows that it is possible to form a conductive film having excellent electromagnetic shielding efficiency.

In the conditions of Example 1, the supersaturated state was reached by drying for 2.5 to 5 minutes, but the conditions in which the coating solution reached the 'saturated state' may vary depending on the type of the metal precursor and the solvent, the concentration of the precursor solution, the drying temperature, and the surrounding environment. It will be natural.

Example 3 Characteristics of the Conductive Film According to Deposition Times

The conductive film was prepared at various precursors, precursor concentrations, and deposition times, and analyzed for its properties.

(1) Characteristic change by changing precursor type and deposition frequency

A conductive film was prepared using various precursor solutions and analyzed for its properties.

It was conditions for 2.5 minutes of drying time and 8 minutes of plasma treatment.

4 is an AgNO ₃ solution, FIG. 5 is an H ₂ PtCl ₆ .xH ₂ O solution, and FIG. 6 is a graph showing sheet resistance according to the number of depositions of a conductive film formed using a HAuCl ₄ solution. 5 shows the sheet resistance change according to the number of times of deposition of the conductive film formed by using 0.1MH ₂ PtCl ₆ ㆍ xH ₂ O solution from 1 to 8 times, and the lower figure shows the sheet resistance change from 4 times to 8 times. Is a graph showing an enlarged view. In addition, the upper drawing of FIG. 6 shows the sheet resistance change according to the number of deposition times of the conductive film formed using 0.1M HAuCl ₄ solution from 1 to 8 times, and the lower drawing further enlarges the sheet resistance change from 3 to 8 times. It is a graph shown.

As can be seen in Figures 4 to 6, the surface resistance is inversely proportional to the number of deposition irrespective of the type of precursor showed that the electrical conductivity of the conductive film increases as the number of deposition increases.

FIG. 7 shows the conductive film formed by each metal precursor (0.1 M AgNO ₃ solution, 0.1 MH ₂ PtCl ₆ · xH ₂ O solution, 0.1 M HAuCl ₄ solution) when the number of depositions was equally applied four times and eight times, respectively. As a graph comparing the sheet resistance, it was confirmed that the sheet resistance was high in the reverse order of silver>gold> platinum in the order of high electrical conductivity, so that the characteristics of the metal were reflected in the conductive film in the case of the conductive film formed under the same conditions.

(2) Changes in characteristics depending on precursor concentration and deposition frequency

A conductive film was prepared by increasing the number of depositions 1 to 5 times under 0.5M AgNO ₃ solution, 2.5 minutes drying time, and 7 minutes plasma treatment.

The produced conductive film photograph is shown in FIG. 8. As can be seen, as the number of depositions increased, the conductive film was formed more uniformly and clearly.

An electron micrograph of the conductive film deposited five times is shown in FIG. 9. As can be seen in the figures, agglomerative cluster layers of several hundreds to several micrometers thick formed three-dimensionally by irregularly entangled metal nanoparticle aggregates of various sizes ranging from tens to hundreds of nm and roughly silk cocoon shapes. .

Although not shown, the aggregate size increased with the concentration of the precursor solution and the thickness of the cluster layer also increased in the range of 0.5-2.0 μm.

The sheet resistance of the conductive film thus prepared was 3.6, 0.4 and 0.2, respectively. 0.1 and 0.01, the electric conductivity of the conductive film increased as the number of deposition increased in inverse proportion to the number of deposition.

Example 4 Characteristics of the Conductive Film According to Precursor Concentration

(1) Example of deposition once

The conductive film was prepared at different concentrations of AgNO ₃ solution and its properties were evaluated. The number of depositions was applied equally to one time. It was conditions for 2.5 minutes of drying time and 8 minutes of plasma treatment.

① sheet resistance

10 is a graph showing the results. As can be seen in FIG. 10, the sheet resistance of the conductive film decreased as the concentration of the precursor increased. Although not shown in the data, when the precursor concentration is 1M or more, the sheet resistance tended to increase according to the measurement position.

(2) Example of deposition five times by concentration

The conductive film was prepared at different concentrations of AgNO ₃ solution and its properties were evaluated. The number of depositions was the same five times. It was conditions for 2.5 minutes of drying time and 8 minutes of plasma treatment.

11 shows the sheet resistance and the surface roughness of the conductive film in a graph. As shown in the drawing, when the precursor solution concentration was 0.5 M, the sheet resistance was the lowest, and above that, the sheet resistance reduction effect no longer occurred. The surface roughness of the conductive film was also the lowest when it was 0.5M. Therefore, it can be estimated that the conductive film having the best function when the metal precursor concentration is 0.5M under the process conditions of this embodiment can be prepared.

12 is a graph showing the shielding rate according to the concentration of the precursor solution, showing a high shielding rate at 0.5 ~ 0.9M, the lower the shielding rate is significantly lower or higher. The low shielding rate at low concentrations is associated with a high sheet resistance, and the lower shielding rate at higher concentrations may be due to the nonuniformity of the conductive film with an increase in sheet resistance.

Example 5 Characteristics of the Conductive Film According to the Plasma Treatment Time

It dried for 2.5 minutes using the 1M AgNO ₃ solution, and the conductive film was prepared by varying the plasma treatment time. The number of depositions was the same five times.

FIG. 13 is a graph showing the sheet resistance of the conductive film. As the plasma treatment time increases, the sheet resistance gradually decreases.

14 is a graph showing the shielding rate according to the plasma treatment time. It can be seen that the highest shielding rate is shown in the plasma treatment for 7-8 minutes. This shows that there is an optimal plasma treatment time, which means that the optimum treatment time can be found according to the type and concentration of the precursor coating solution. Although not shown, when the plasma is treated for 9 minutes or more, a phenomenon in which silver oxide is formed on the surface of the conductive film turns black.

The above embodiments are merely examples for easily describing the contents and scope of the technical idea of the present invention, and thus the technical scope of the present invention is not limited or changed. It will be apparent to those skilled in the art that various modifications and variations are possible within the scope of the present invention based on these examples.

Claims (8)

(A) coating a metal precursor solution on the surface of the substrate of any material to form a metal precursor coating layer;
(B) drying the metal precursor coating layer for a predetermined time to induce supersaturation of the solution; And
(C) treating the supersaturated metal precursor coating layer with plasma to form a metal cluster layer;
Containing, conductive film manufacturing method consisting of a metal cluster layer.
The method according to claim 1,
The method comprising the steps (A) to (C) is repeated 3 to 15 times, characterized in that the conductive film manufacturing method consisting of a metal cluster layer.
The method according to claim 1,
The substrate is a conductive film manufacturing method comprising a metal cluster layer, characterized in that the conductor or insulator.
The method according to claim 3,
The material of the substrate is a metal, glass, polymer resin, paper, carbon nanotubes, graphene and graphite, characterized in that the combination of one or two or more selected from the group consisting of, a conductive film production method consisting of a metal cluster layer.
The method according to any one of claims 1 to 3,
Plasma treatment of the step (C) is characterized in that at a normal pressure, a conductive film manufacturing method consisting of a metal cluster layer.
The method according to any one of claims 1 to 3,
The concentration of the solution of the metal precursor of step (A) is characterized in that 0.1 ~ 1.0M, conductive film manufacturing method consisting of a metal cluster layer.
The method according to any one of claims 1 to 3,
Before the coating of the precursor solution in the step (A), further comprising the step of pre-treating the surface of the substrate for 0.1 to 15 minutes, the conductive film manufacturing method consisting of a metal cluster layer.
An electromagnetic wave shielding agent comprising a conductive film formed by the method of any one of claims 1 to 3.

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