WO2017222311A1

WO2017222311A1 - Method for preparing metal composite structure in which metal nanowire and metal particles are welded

Info

Publication number: WO2017222311A1
Application number: PCT/KR2017/006553
Authority: WO
Inventors: 박성주; 이효주; 홍상현; 오세미
Original assignee: 광주과학기술원
Priority date: 2016-06-21
Filing date: 2017-06-21
Publication date: 2017-12-28
Also published as: KR20170143307A; KR101828578B1

Abstract

Provided is a method for preparing a metal composite structure formed by using a work function and a standard electrode potential difference of a metal nanowire and metal particles. A metal nanowire and metal particles are formed on a conductive substrate, and water is introduced such that the metal particles are welded to the metal nanowire by a work function and a standard electrode potential difference, and thus a metal composite structure is formed. The formed metal composite nanostructure does not deteriorate crystallinity of the metal nanowire, and can be used as a transparent electrode material by using an environmentally-friendly nano welding technique.

Description

Method for manufacturing metal composite structure welded with metal nanowires and metal particles

The present invention relates to a method for manufacturing a metal nanowire, and more particularly, to a method for manufacturing a metal composite structure formed by welding metal particles and metal nanowires.

Transparent electrodes are applied to various optical devices such as solar light, displays, light emitting diodes, etc., and much research is being conducted. In the case of the ITO transparent electrode commercialized as a transparent electrode, a high temperature thin film process of 300 ° C. or higher is required to form a high conductivity thin film. However, in the case of flexible polymer substrates (PET, PEN, PAR, PES), it is difficult to process at a temperature of 200 degrees or more, so that an amorphous ITO thin film deposited at room temperature is used as a flexible transparent electrode. Amorphous ITO thin films have high sheet resistance with higher defect density than crystalline ITO. In addition, there is a limit to the application to the flexible element because the durability against bending is weak.

Therefore, transparent electrodes based on metal nanowires have been actively studied as transparent electrode materials applicable to flexible devices. The metal nanowire-based transparent electrode has a problem that the electrical properties are improved when the metal nanowire density is high, but the transmittance is decreased. Therefore, a transparent electrode having high permeability and high conductivity characteristics using only a small amount of metal nanowires has been studied. In particular, nano-welding technology for welding junctions between metal nanowires has been studied as a method of improving conductivity characteristics in metal nanowire-based transparent electrodes.

As nano welding technology, various methods such as a method using heat, plasma welding using light, and chemical welding using salt and reducing agent have been studied. However, the conventional nano welding technology has a disadvantage of deteriorating the crystallinity of the metal nanowires or using additional chemicals to increase the process cost and lower the stability.

Therefore, it is also a problem to be solved that process cost improvement and stability are inhibited due to the reduction in crystallinity of the metal nanowires to which the conventional nano welding technology is applied and additionally used chemicals.

The problem to be solved by the present invention is to provide a method for producing a metal composite structure welded metal nanowires and metal particles as a transparent electrode material.

The present invention for solving the above problems, forming a metal nanowire on a conductive substrate, forming a metal particle on the conductive substrate on which the metal nanowire is formed, and by applying water to weld the metal nanowires It can provide a method for producing a metal composite structure comprising the step of.

In the forming of the metal particles on the conductive substrate on which the metal nanowires are formed, the metal particles may include a method of manufacturing a metal composite structure, wherein the metal particles have a lower work function and a standard electrode potential than the metal nanowires. have.

In the forming of the metal particles on the conductive substrate on which the metal nanowires are formed, the metal particle formation method may be performed by applying a solution to particles or metal particles having a core shell structure in which metal oxide particles are surrounded by vacuum deposition or metal particle surfaces. It is possible to provide a method for producing a metal composite structure, characterized in that formed using a solution process.

In the step of applying water to the metal nanowires by applying water, the method of manufacturing a metal composite structure further comprises adding a salt containing a metal ion or adjusting the acidity to increase the reaction rate can do.

In the step of applying water to the metal nanowires by welding, electrons of the metal particles having a low work function and a standard potential electrode may be released, thereby providing a method of manufacturing a metal composite structure.

The metal particles have a lower work function than the metal nanowires, and electrons separated from the metal particles move to the junction portion of the metal nanowires through the conductive substrate. can do.

The welding of the metal nanowires and the metal particles by coating water may provide a method of manufacturing a metal composite structure, in which water is coated on the substrate and reacted for 1 to 5 minutes.

The step of applying water to apply water to weld the metal nanowires and the metal particles, after the water coating reaction is a method of manufacturing a metal composite structure, characterized in that to remove the water applied on the conductive substrate with nitrogen gas It may include.

According to the method for manufacturing a metal composite structure according to the present invention, using metal particles and metal nanowires, water is applied to weld the metal particles to the metal nanowires to form a metal composite structure is not inhibited even in the crystallinity of the metal nanowires The electrical conductivity and the light transmittance can be improved without.

In addition, the manufactured metal composite structure can be manufactured without chemicals added to an environmentally friendly process of applying water by welding, and thus can have high economical efficiency as a material of a transparent electrode.

However, the effects of the invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a view for explaining a method of manufacturing a metal composite structure according to an embodiment of the present invention.

2 is an SEM image for explaining a metal composite structure formed according to the presence or absence of a conductive substrate according to an embodiment and a comparative example of the present invention.

3 is a graph for comparing the sheet resistance according to an embodiment of the present invention and a comparative example.

4 is a light transmittance graph according to an embodiment of the present invention.

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

Embodiment of the present invention can be modified in various other forms, the scope of the present invention is not limited to the embodiments described below. In addition, the embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Therefore, the shape and size of the elements in the drawings may be exaggerated for more clear description, and the elements denoted by the same reference numerals in the drawings are the same elements.

Example

Referring to Figure 1, a method of manufacturing a metal composite structure of the present invention is disclosed.

First, the metal nanowires 100 are formed on the conductive substrate 10.

Subsequently, the metal particles 200 are formed on the metal nanowires 100.

Finally, by applying water, the metal particles 200 are welded to the metal nanowires 100 to form a metal composite structure 300.

Hereinafter, the manufacturing method disclosed in FIG. 1 will be described in more detail.

The metal nanowires 100 are formed on the conductive substrate 10, and the metal particles 200 are formed on the metal nanowires 100. The method of forming the metal particles 200 may be formed using a vacuum deposition or a solution process of applying a solution to the particles of the core shell structure or the metal particles 200 surrounded by metal oxide particles on the surface of the metal particles 200. . In addition, the metal nanowires 100 and the metal particles 200 formed on the conductive substrate 10 pass current through the ohmic junction with the conductive substrate 10. Depending on the type of semiconductor and the relative work function difference between the metal and the semiconductor, current characteristics may vary and may have an ohmic junction or a rectifying junction.

However, the metal particles 200 have a lower work function and lower standard electrode potential than the metal nanowires 100, and the crystallinity and structure of the metal particles 200 are not limited. The work function is a measure of the attraction force of the electrons in the metal to bond, and the energy required to excite one electron from the metal surface. That is, when the work function is low, the bonding force of the electrons is relatively low, and the electrons of the metal particles 200 having the low work function are easily separated.

As a result, the metal particles 200 have a lower work function than the metal nanowires 100, and electrons separated from the metal particles 200 move to the junction portion of the metal nanowires 100 through the conductive substrate 10. do. In addition, water may be applied and reacted for 1 to 5 minutes. In the step of applying water and welding the metal nanowires 100, salts containing metal ions may be added or acidity may be adjusted to increase the reaction rate in water.

As a result, electrons of the metal particles 200 are supplied along the conductive layer to the metal nanowires 100 having a large standard electrode potential, and many electrons are present at the junctions of the metal nanowires 100 to generate relatively strong negative charges. Will be visible.

Therefore, the cations of the metal particles 200 dissolved in the water are combined to move to the portion having a negative charge in order to meet the standard state. Therefore, the metal particles 200 are dissolved and the metal particles 200 are welded to the metal nanowire 100 junction to form the metal composite structure 300.

Referring to FIG. 2, an SEM image for explaining a metal composite structure 300 formed according to the presence or absence of a conductive substrate 10 according to an embodiment of the present invention is disclosed.

In FIG. 2A, a metal composite structure 300 manufactured by the manufacturing method disclosed in FIG. 1 is disclosed.

First, the metal nanowires 100 are formed on the conductive substrate 10.

Subsequently, the metal particles 200 are formed on the metal nanowires 100.

The formed metal particles 200 have a lower work function and a standard electrode potential than the metal nanowires 100, and the size of the metal particles 200 is not limited.

Subsequently, the application of water initiates the reaction. Water is applied onto the conductive substrate 10 and reacted for 1 to 5 minutes. In addition, the metal particles 200 are welded with a metal nanowire 100 having a large work function and a standard electrode potential to form a metal composite structure 300.

Finally, after the water coating reaction, the applied water on the conductive substrate 10 is removed with nitrogen gas.

2 (b) to (c) disclose comparative examples.

Referring to (b) of FIG. 2, an SEM image of the synthesis of the metal nanowires 100 and the metal particles 200 on the glass is disclosed. Hereinafter, the preparation method will be described in detail in Comparative Example 1.

Comparative Example 1

Synthesis of Metal Nanowires and Metal Particles on Glass

First, the metal nanowires 100 are formed on the glass. Subsequently, the metal particles 200 are formed on the metal nanowires 100. The formed metal particles 200 may have a work function and a standard electrode potential smaller than those of the metal nanowires 100. Finally, apply water for 10 minutes and remove the water with nitrogen gas.

2 (b) is formed by the same manufacturing method as (a) of FIG. 2, but (a) of FIG. 2 shows that the metal nanowires 100 and the metal particles 200 are formed on the conductive substrate 10. 2B is formed on the glass.

In FIG. 2B, the metal particles 200 are not welded to the metal nanowires 100, and the metal particles 200 deposited on the glass are distributed on the front surface, and the metal nanoparticles are interposed between the metal particles 200. The wire 100 is located. The metal nanowires 100 intersect on parallel lines which are not equal to each other. The conductive substrate 10, the metal particles 200, and the metal nanowires 100 are ohmic bonded to each other, and electrons of the metal particles 200 are transferred to the metal nanoparticles by the conductive substrate 10 due to the difference in work function and standard electrode potential. The metal particles 200 are welded to the metal nanowires 100 by moving to the wire 100. However, in the case of glass, since no current flows, the movement of electrons does not occur, and thus the metal particles 200 and the metal nanowires 100 cannot be welded to each other.

Referring to FIG. 2C, an SEM image of the metal composite structure 300 formed by welding the metal particles 200 on the SI substrate with the metal nanowires 100 is disclosed. Hereinafter, the preparation method will be described in detail in Comparative Example 2.

Comparative Example 2

Metal composite structure formed on SI substrate

An SI substrate is used as the conductive substrate 10. First, a metal nanowire 100 is formed on an SI substrate. Subsequently, the metal particles 200 are formed on the metal nanowires 100. Finally, apply water for 10 minutes and remove the water with nitrogen gas.

2 (a) to 2 (c) are manufactured by the same manufacturing method. However, the SI substrate is used as the conductive substrate 10 in (c) and water is applied to move the electrons of the metal particles 200 through the SI substrate, which is the conductive substrate 10. 100 to be welded to form a metal composite structure (300). Therefore, the kind of the conductive substrate 10 used in the manufacturing method of applying the water to the metal particles 200 by welding the metal nanowires 100 to form the metal composite structure 300 is not limited.

Referring to FIG. 3, sheet resistance graphs according to Examples and Comparative Examples are disclosed.

3A illustrates a sheet resistance graph according to an embodiment.

The first sample is a metal nanowire 100 formed on the conductive substrate 10.

In the second sample, the metal particles 200 are formed at 5 nm on the first sample.

The third sample was reacted for 10 minutes by applying water on the second sample and dried with nitrogen gas.

The fourth sample was reacted for 24 hours by applying water on the second sample and dried with nitrogen gas.

3 (b) discloses a sheet resistance graph according to a comparative example.

The first sample is a metal nanowire 100 formed on the glass.

3 (a) shows that the metal nanowires 100 and the metal particles 200 are formed on the conductive substrate 10 to have overall low sheet resistance compared to (b) formed on the glass. (b) is the metal nanowires 100 and the metal particles 200 formed on the non-conductive glass, and generally have a high sheet resistance value. In addition, when the metal particles 200 are formed on the metal nanowire 100, the sheet resistance tends to decrease. In the case of (a), the sheet resistance has a relatively high sheet resistance due to the glass, and the sheet resistance due to the formation of the metal particles 200 is greatly reduced, but when the water is applied, the sheet resistance is increased. In the case of (b), the metal nanowires 100 and the metal particles 200 are formed on the conductive substrate 10 to have a relatively low sheet resistance, and after the water is applied, the sheet resistance value is greatly reduced. In the case of (a), the fourth sample measured the sheet resistance after 24 hours of water application, the sheet resistance value similar to that of 1 to 5 minutes after the third sample water application reaction time is maintained. This is an irreversible reaction in which the metal particles 200 are dissolved and welded to the junctions of the metal nanowires 100, and thus no chemical reactions proceed.

In particular, the metal nanowires 100 and the metal particles 200 are formed on the conductive substrate 10 and water is coated to weld to form the metal composite structure 300 (a) and the metal nanowires on the glass ( Compared with (b) in which 100) and the metal particles 200 are not welded, (a) generally has a low sheet resistance value.

Therefore, the metal nanowires 100 and the metal particles 200 are formed on the conductive substrate 10 to induce electron movement and the metal particles 200 are formed of the metal nanowires 100 according to the work function and the standard electrode potential difference. As a result of the welding, it can have a low sheet resistance.

In Comparative Example 1, the metal nanowires 100 and the metal particles 200 are formed on glass. The metal particles 200 on the glass are not welded to the metal nanowires 100. Therefore, the remaining metal particles 200 prevent the light from being transmitted, thereby lowering the light transmittance.

On the other hand, in the present invention, since the metal nanowires 100 and the metal particles 200 are formed on the conductive layer and the metal particles 200 are welded to the metal nanowires 100, the remaining metal particles 200 are formed. The light transmittance is improved by decreasing.

Accordingly, in the metal composite structure 300, the metal nanowires 100 and the metal particles 200 are formed on the conductive substrate 10, and the metal particles 200 are dissolved in water, so that the work function and the standard electrode potential difference are different. It is formed by welding to the metal nanowires (100). The formed metal composite structure 300 does not reduce the crystallinity of the metal nanowires 100 and is welded in water, so that no additional compound for welding may be required, thereby reducing process costs. In addition, the formed metal composite structure 300 may reduce sheet resistance and improve light transmittance, and thus may be used as a material of a transparent electrode.

Claims

Forming metal nanowires on the conductive substrate;

Forming metal particles on the conductive substrate on which the metal nanowires are formed; And

Method of manufacturing a metal composite structure comprising the step of welding the metal nanowires by applying water.
The method of claim 1, wherein the forming of the metal particles on the conductive substrate on which the metal nanowires are formed

The metal particle has a lower work function and a standard electrode potential than the metal nanowires manufacturing method of a metal composite structure.
The method of claim 2, wherein the forming of the metal particles on the conductive substrate on which the metal nanowires are formed

The metal particle formation method is a method of manufacturing a metal composite structure, characterized in that formed using a vacuum vapor deposition or a solution process of applying a solution to the particles or metal particles of the core shell structure surrounded by metal oxide particles on the metal particles surface.
The method of claim 1, wherein in the step of applying water to the metal nanowires,

Method for producing a metal composite structure further comprises the addition of a salt containing a metal ion or to adjust the acidity to increase the reaction rate.
The method of claim 1, wherein in the step of applying water to the metal nanowires,

A method of manufacturing a metal composite structure, wherein electrons of a metal particle having a low work function and a standard potential electrode are separated.
3. The metal complex of claim 2, wherein the metal particles have a lower work function than the metal nanowires, and electrons separated from the metal particles move to the junction portion of the metal nanowires through the conductive substrate. Method for producing a structure.
The method of claim 1, wherein the welding of the metal nanowires with the metal particles by applying water is performed.

Method of producing a metal composite structure, characterized in that for 1 minute to 5 minutes by applying water on the substrate.
The method of claim 7, wherein the step of applying water by applying water to weld the metal nanowires with the metal particles

After the water coating reaction method for producing a metal composite structure characterized in that to remove the water applied on the conductive substrate with nitrogen gas.