KR101514743B1 - The method for manufacturing patterned metal nanowire transparent electrode and the patterned metal nanowire transparent electrode thereby - Google Patents

Abstract

The present invention relates to a method of manufacturing a metal nanowire transparent electrode having a pattern and a metal nanowire transparent electrode having a pattern formed thereby, and more particularly, to a method of manufacturing a metal nanowire transparent electrode by forming a SiO ₂ pattern on a substrate (step 1); The SiO ₂ of step 1 Forming a metal seed layer on the pattern (step 2); And growing a nanowire using a solution containing a reducing agent and a metal precursor from the metal seed layer in step 2 (step 3), and a method of manufacturing a patterned metal nanowire transparent electrode, To provide a transparent metal nanowire transparent electrode.
Unlike conventional metal nanowires synthesized by first forming a metal seed wire layer on a substrate patterned with SiO ₂ to grow metal nanowires and patterning them after coating them, complex and difficult processes are not required And the manufacturing cost is reduced. Further, since the nanowires are directly synthesized on the substrate, the adhesion between the substrate and the nanowires can be increased.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing a metal nanowire transparent electrode having a pattern formed thereon and a patterned metal nanowire transparent electrode,

The present invention is a metal nanowire transparent electrode manufacturing method having a pattern formed, and this relates to a metal nanowire transparent electrode pattern is formed is prepared in accordance with, after pre-forming an SiO ₂ pattern on the substrate, growing the metallic nanowires on the pattern And a metal nanowire transparent electrode having a pattern formed by the method.

The transparent conductor refers to a thin conductive film coated on a high transmittance insulating surface or substrate. The transparent conductor can be made to have surface conductivity while maintaining proper optical transparency.

Such a surface conductive transparent conductor is widely used as a transparent electrode in a flat liquid crystal display, a touch panel, an electroluminescent device, a thin film photovoltaic cell, And is widely used as an electrification-preventing layer and an electromagnetic wave shielding layer.

[0003] A lot of research has been conducted on transparent electrodes using the transparent conductor to realize transparent electronic elements and flexible printed electronic elements.

In general, a well-known transparent electrode is indium-doped tin oxide (ITO). Recently, attempts have been made to manufacture transparent electrodes using carbon nanotubes, conductive polymers or silver nanowires.

BACKGROUND OF THE INVENTION Vacuum deposited metal oxide such as indium tin oxide (ITO) is an industry standard for providing optical transparency and electrical conductivity to dielectric surfaces such as glass and polymeric films. Material.

In the case of such an ITO electrode, transparency of 80% or more and low sheet resistance of 10 to 50 Ω / □ are widely used in transparent electronic device applications.

However, the metal oxide film is weak and prone to damage by warping or other physical stresses. In addition, they require high deposition temperatures and / or high annealing temperatures to achieve high conductivity levels.

In addition, it is also very limited to apply a metal oxide film on a flexible substrate, since adhesion of the metal oxide film to substrates that are susceptible to moisture, such as plastic and organic substrates, for example, polycarbonate, may also be a problem .

Furthermore, in order to deposit a metal oxide film, a vacuum deposition process such as a sputtering or a chemical vapor deposition process must be performed, which is costly and requires special equipment. In addition, when patterns and circuits are formed, There is a problem in that it is necessary to perform a patterning process which requires a lot of time.

In order to overcome this problem, studies have been actively conducted to form a transparent electrode by spray coating or printing a single-wall or double-walled carbon nanotube, or to print a conductive polymer such as PEDOT to form a transparent electrode. However, The use of metal nanowires such as silver nanowires is considered to be an optimal solution for manufacturing transparent electrodes having excellent electrical conduction characteristics comparable to ITO.

On the other hand, nanoparticles are used in a wide range of fields such as electronic materials, sensors, adsorbents, chromatography fillers, and catalyst carriers because they exhibit unique electrical, magnetic, optical, and mechanical properties compared to bulk phase materials having the same chemical composition have.

In particular, many metallic materials with one-dimensional structures (rods, wires, tubes, belts) are expected to play an important role in forming nanoscale devices. Recently, nanowires have been actively studied for their manufacture and characterization among materials having a one-dimensional structure.

Silver nanowires have a short axis width of 10 to 100 nm and a long axis length of 3 to 100 mu m so that a small amount of silver nanowires are networked and connected to each other like a network and have high electrical conductivity characteristics and 80 To 90% or more of transparency.

Silver nanowire transparent electrodes developed until now have been formed by synthesizing silver nanowires and forming them into ink or paste, and then performing a front coating such as spin coating or spray coating on the substrate.

In the case of the silver nanowire transparent electrode manufactured by the above method, there is a problem that the patterning process such as forming a pattern by burning with a high output laser is difficult or complicated. In addition, in order to improve the adhesion between the substrate and the silver nanowire, an inorganic filler has to be added, or it has been troublesome to form the protective film separately from the protective film by using a protective polymer material.

Korean Patent Laid-Open Publication No. 10-2013-0072064 discloses a nanowire composition and a method of manufacturing a transparent electrode as a conventional technique related to silver nanowire transparent electrodes. Specifically, there is provided a method comprising: preparing a nanowire composition; Coating the nanowire composition on a substrate; And heat treating the nanowire composition, wherein the nanowire composition comprises: a metal nanowire; Organic binders; Surfactants; And a solvent, wherein the metal nanowires have a diameter of 30 nm to 50 nm and a length of 15 to 40 μm, and the weight percentage of the metal nanowires is 0.01% to 0.4% .

However, when the transparent electrode is manufactured by the above-described manufacturing method, there is a problem in that the process of forming the pattern is complicated and the adhesion of the patterned electrode and the substrate is not easy.

The inventors of the present invention conducted research on a method for manufacturing a metal nanowire transparent electrode having improved adhesion and improved electrode patterning. In this process, a pattern is formed on a substrate with SiO ₂ , and a metal nano- A method of manufacturing a metal nanowire transparent electrode in which a pattern for growing a wire is formed has been developed and the present invention has been completed.

SUMMARY OF THE INVENTION

And a method of manufacturing a metal nanowire transparent electrode in which a pattern is formed.

Another object of the present invention is

There is provided a metal nanowire transparent electrode having a pattern formed according to the above method.

According to an aspect of the present invention,

Forming a SiO ₂ pattern on the substrate (step 1);

The SiO ₂ of step 1 Forming a metal seed layer on the pattern (step 2); And

And growing a nanowire using a solution containing a reducing agent and a metal precursor from the metal seed layer in step 2 (step 3).

Further, according to the present invention,

A metal nanowire transparent electrode having a pattern formed according to the above method is provided.

The method of fabricating a metal nanowire transparent electrode with a pattern according to the present invention is characterized in that a metal seed wire is formed on a substrate patterned with SiO ₂ to grow metal nanowires, Unlike the conventional patterning method, complicated and difficult processes are not required, and the manufacturing cost is reduced.

Further, since the nanowires are directly synthesized on the substrate, the adhesion between the substrate and the nanowires can be increased.

1 is a schematic view showing a method of manufacturing a metal nanowire transparent electrode in which a pattern according to the present invention is formed;
FIG. 2 is a schematic view showing a process of forming a metal nanowire according to the present invention; FIG.
FIG. 3 is a photograph of a metal nanowire transparent electrode formed with the pattern prepared in Example 1 by scanning electron microscopy (SEM). FIG.

The present invention

Forming a SiO ₂ pattern on the substrate (step 1);

Forming a metal seed layer on the SiO ₂ pattern of step 1 (step 2); And

And growing a nanowire using a solution containing a reducing agent and a metal precursor from the metal seed layer in step 2 (step 3).

Here, an example of a method for fabricating a metal nanowire transparent electrode having a pattern according to the present invention is schematically shown in FIG. 1,

Hereinafter, a method of fabricating a metal nanowire transparent electrode having a pattern according to the present invention will be described in detail.

In the method of manufacturing a metal nanowire transparent electrode having a pattern according to the present invention, step 1 is a step of forming a SiO ₂ pattern on a substrate.

Conventionally, there has been a problem that it is difficult or complicated to pattern the metal nanowires after synthesizing the metal nanowires and coating them on the substrate in the form of ink or paste, and then burning them with a high-power laser to form a pattern.

On the other hand, in the method of manufacturing a transparent electrode according to the present invention, since the process is simple since the SiO ₂ pattern is formed in advance in the step 1 and the metal nanowires are grown on the pattern, the nanowires are grown directly on the substrate, The adhesion between the metal nanowires can be improved.

Specifically, a photoresist layer is formed on a region where a metal nanowire is to be formed on a substrate, and an opposite region is exposed to etch the exposed region with an SiO ₂ etchant, a step to leave the _second layer can form an SiO ₂ layer.

In the method for fabricating a metal nanowire transparent electrode having a pattern according to the present invention, the step 2 is a step of forming a metal seed layer on the SiO ₂ pattern of the step 1.

Specifically, the substrate on which the SiO ₂ pattern of step 1 was formed was coated with SiO ₂ So that a metal seed layer is formed only on the surface of SiO ₂ .

At this time, the metal in step 2 may be a precious metal, and the precious metal may be at least one selected from the group consisting of platinum, gold, silver and copper, but the metal is not limited thereto.

The metal seed layer of step 2 may be formed using a coupling agent.

The coupling agent may be SiO ₂ Lt; RTI ID = 0.0 > layer. Therefore, the substrate on which SiO ₂ is formed is reacted with the coupling agent to selectively adsorb the coupling agent only on the SiO ₂ surface, and then the substrate is immersed in the metal seed solution to form the metal seed layer only on the SiO ₂ surface.

Wherein the coupling agent comprises at least one aminoalkylsilane group selected from the group consisting of 3-aminopropyltriethoxysilane, 4-aminopropyltrimethoxysilane and 4-aminobutyltrimethoxysilane, But the coupling agent is not limited thereto.

In the method for fabricating a metal nanowire transparent electrode having a pattern according to the present invention, the step 3 is a step of growing a nanowire from the metal seed layer of the step 2 using a solution containing a reducing agent and a metal precursor.

Specifically, when a substrate on which a metal seed layer is formed is immersed in a solution containing a reducing agent and a metal precursor, a metal precursor is reduced on the metal seed layer to grow metal nanowires.

Conventionally, the process has been complicated by synthesizing metal nanowires and then coating them on the substrate by making them ink or paste.

On the other hand, in the method of manufacturing a transparent electrode according to the present invention, since the metal nanowires are directly grown on the substrate, the process is simple and the adhesion between the substrate and the metal nanowires can be improved by growing the nanowires directly on the substrate.

The growth of the metal nanowires of step 3 may be carried out by further including a ligand in the solution of step 3 above.

The ligand can make strong bonds with the exposed metal seed layer. Therefore, when the substrate on which the metal seed layer is formed is immersed in a solution containing the ligand, the reducing agent, and the metal precursor, the lower part of the metal seed layer has no strong binding ligand. Thus, Bonding can be maintained to prevent bonding with the metal precursor, and metal nanowires can grow vertically from the lower portion of the metal seed layer. That is, the metal nanowires are made of SiO ₂ Lt; RTI ID = 0.0 > metal seed layer. ≪ / RTI >

At this time, the ligand may be at least one selected from the group consisting of mercapto aliphatic acid and mercapto aromatic acid. The ligand may be 4-mercaptobenzoic acid, 4-mercapto-2-methoxy-benzoic acid and 3-mercaptopropionic acid But the ligand is not limited thereto, and a ligand capable of strong binding with a metal electrode to be formed can be appropriately selected and used.

The reducing agent in step 3 reduces the metal from the metal precursor so that the metal nanowires can grow.

At this time, the reducing agent may be at least one selected from the group consisting of borohydride, hydrazine, citric acid or its salt and reducing sugar of L-ascorbic acid, alkali metal or alkaline earth metal, but the reducing agent is not limited thereto .

The metal precursor of step 3, _{AgNO 3, AgCl, AgNO 3,} HAuClO 4, H 2 PtCl 6 And H ₂ Pt (OH) ₆ may be used, but the metal precursor is not limited thereto.

The method may further include the step of forming the SiO ₂ pattern of the step 1, followed by O ₂ plasma or UV ozone treatment for 5 minutes to 1 hour to make the surface hydrophilic.

When the surface is made hydrophilic, the coupling agent can be more easily adsorbed only on SiO ₂ .

The nanowire of the step 3 may be grown and then coated with a polymer protective film.

When the polymer protective film is coated on the nanowire transparent electrode of step 3, the adhesion between the metal nanowire and the substrate can be further improved.

The polymer may be selected from the group consisting of polyurethane, polyether urethane, polyurethane copolymer, cellulose acetate, cellulose, acetate butyrate, cellulose acetate propionate, cellulose derivatives, polymethyl methacrylate, polymethyl acrylate, , Polyvinyl acetate copolymer, polyvinyl acetate, polyvinyl pyrrolidone, polyvinyl alcohol, polyperfuryl alcohol, polystyrene, polystyrene copolymer, polyethylene oxide, polypropylene oxide, polyethylene oxide copolymer, polypropylene oxide copolymer, At least one member selected from the group consisting of polycarbonate, polyvinyl chloride, polycaprolactone, polyvinyl fluoride, polyvinylidene fluoride copolymer and polyamide may be used, It is not.

On the other hand, the metal of the metal seed layer of step 2 and the metal of the metal nanowire of step 3 may be the same.

Further, according to the present invention,

The present invention provides a metal nanowire transparent electrode having a pattern formed according to the above manufacturing method.

The metal nanowire transparent electrode having a pattern according to the present invention can be produced by first forming a metal nanowire by forming a metal seed layer on a substrate patterned with SiO _{2 so} as to synthesize a conventional metal nanowire, Unlike the conventional method, since complicated and difficult process is not required, it can be manufactured easily and can be provided at a low price.

In addition, since the nanowires are directly synthesized on the substrate, the adhesion between the substrate and the nanowires is increased, and a metal nano wire transparent electrode having both a good adhesion and an improved electrode patternability can be provided.

≪ Example 1 >

Step 1: A photoresist layer was formed on the glass substrate in a region opposite to the electrode pattern to prevent exposure of the SiO ₂ layer, and conversely, the glass surface SiO ₂ layer of the desired pattern was exposed.

The exposed SiO ₂ layer was treated with O ₂ plasma or UV ozone for 10 minutes to make the surface hydrophilic.

Step 2: reacting the ethoxy silane (APTES) substrate on which the SiO ₂ in the step formed on the coupling agent to the 3-aminopropyl of from 5 to 10mM for 0.5 to 1 hour SiO ₂ APTES was selectively adsorbed only on the surface.

sodium citrate tribasic dihydrate was immersed in a silver seed solution stabilized in an aqueous solution for 2 hours and then rinsed twice with ultrapure water to form a seed layer only on the APTES surface.

Step 3: Silver substrate was immersed in a solution containing 30 mM of 4-mercaptobenzoic acid (MBA) ligand, 260 mM of L-ascorbic acid reducing agent and 100 mM of metal precursor AgNO ₃ for 15 to 30 minutes to form silver seed layer To grow the silver nanowires.

After the growth was completed, the substrate was washed with ultrapure water two to three times, and then dried to produce a patterned metal nanowire transparent electrode.

≪ Example 2 >

The procedure of Example 1 was repeated except that 3-mercaptopropionic acid ligand was used in Step 3 of Example 1 to prepare a patterned metal nanowire transparent electrode.

≪ Comparative Example 1 &

Step 1: Silver nanowires were synthesized by the ethylene glycol reduction method.

Step 2: The silver nanowires were mixed with toluene and applied to a glass substrate, and then the substrate was heated to remove toluene to prepare a silver nanowire transparent electrode layer.

Step 3: The silver nanowire transparent electrode was irradiated with a laser through a photolithography process to produce a patterned metal nanowire transparent electrode.

<Experimental Example 1>

In order to observe the metal nanowire transparent electrode having the pattern formed in Example 1, it was observed with a scanning electron microscope (SEM), and the result is shown in FIG.

As shown in Fig. 3, it can be seen that the silver nanowires are formed uniformly and densely on the substrate.

Thus, it can be seen that the adhesion can be improved by a simple solution process, and a metal nanowire transparent electrode having a pattern can be produced.

<Experimental Example 2>

In order to observe the characteristics of the metal nanowire transparent electrode formed with the patterns produced in Examples 1 and 2 and Comparative Example 1, the surface resistance was measured using a 4-point probe type device (MODEL SRM-232 equipment) The transmittance was measured at a wavelength of 550 nm using a permeability measuring instrument (NDH 5000W), and the adhesion was visually confirmed by peeling-off test using a 3M tape. The results are shown in Table 1.

Example 1 Example 2 Comparative Example 1 Sheet resistance (Ω / □) 17 19 20 Transmittance (%) 93 91 90 Adhesion test ○ ○ ×

(Judgment criterion of adhesion is represented by x: poor,?: Middle, and?: Good).

As shown in Table 1, the cases of Example 1 and Example 2 in which silver nanowire transparent electrodes were produced according to the present invention were compared with those of Comparative Example 1 in which conventional silver nanowires were synthesized by coating them on a substrate again The characteristics of the transparent electrode differing in the sheet resistance and the transmittance were superior.

From the viewpoint of adhesion, it was also found that Examples 1 and 2 in which silver nanowires were directly grown on a substrate were superior to those of Comparative Example 1.

As a result, it can be seen that the transparent electrode manufactured according to the present invention can be manufactured in a simple and inexpensive manner, while having excellent electrical characteristics and adhesion as an electrode.

Claims (13)

Forming a SiO ₂ pattern on the substrate (step 1);
Forming a metal seed layer on the SiO ₂ pattern of step 1 (step 2); And
Growing a nanowire from the metal seed layer of step 2 using a solution containing a reducing agent and a metal precursor (step 3)
The formation of the metal seed layer in the step 2 is carried out using a coupling agent,
Wherein the coupling agent is at least one aminoalkylsilane selected from the group consisting of 3-aminopropyltriethoxysilane, 4-aminopropyltrimethoxysilane, and 4-aminobutyltrimethoxysilane. Wherein the metal nanowire has a pattern formed thereon.
The method according to claim 1,
Further comprising the step of forming an SiO ₂ pattern of the step 1 and then performing O ₂ plasma or UV ozone treatment for 5 minutes to 1 hour to make the surface hydrophilic. Gt;
The method according to claim 1,
Wherein the metal of step 2 is a precious metal.
The method of claim 3,
Wherein the precious metals are at least one selected from the group consisting of platinum, gold, silver and copper.
delete The method according to claim 1,
The growth of the metal nanowires of step 3 is carried out by further comprising a ligand in the solution of step 3,
Wherein the ligand is at least one selected from the group consisting of mercapto-aliphatic acid and mercapto-aromatic acid.
The method according to claim 1,
The growth of the metal nanowires of step 3 is carried out by further comprising a ligand in the solution of step 3,
Wherein the ligand is at least one selected from the group consisting of 4-mercaptobenzoic acid, 4-mercapto-2-methoxy-benzoic acid and 3-mercaptopropionic acid.
The method according to claim 1,
Wherein the reducing agent in step 3 is at least one selected from the group consisting of borohydride, hydrazine, citric acid or its salt and reducing sugar of L-ascorbic acid, alkali metal or alkaline earth metal, Gt;
The method according to claim 1,
The metal precursor of step 3, _{AgNO 3, AgCl, AgNO 3,} HAuClO 4, H 2 PtCl 6 And H ₂ Pt (OH) _{6. The} method for manufacturing a transparent electrode of a metal nanowire according to claim 1,
The method according to claim 1,
The method of claim 1, further comprising the step of growing a nanowire of step 3 and then coating a polymer protective layer.
11. The method of claim 10,
The polymer may be selected from the group consisting of polyurethane, polyether urethane, polyurethane copolymer, cellulose acetate, cellulose, acetate butyrate, cellulose acetate propionate, cellulose derivatives, polymethyl methacrylate, polymethyl acrylate, polyacrylic copolymer, poly Vinyl acetate copolymer, polyvinyl acetate, polyvinyl pyrrolidone, polyvinyl alcohol, polyperfuryl alcohol, polystyrene, polystyrene copolymer, polyethylene oxide, polypropylene oxide, polyethylene oxide copolymer, polypropylene oxide copolymer, polycarbonate Wherein the metal nanowires are at least one selected from the group consisting of polyvinyl chloride, polycaprolactone, polyvinyl fluoride, polyvinylidene fluoride copolymer and polyamide. A transparent electrode method.

The method according to claim 1,
Wherein the metal of the metal seed layer of step 2 and the metal of the metal nanowire of step 3 are the same.
A metal nanowire transparent electrode having a pattern formed according to the manufacturing method of claim 1.

Images