U.S. patent application number 14/128791 was filed with the patent office on 2014-08-07 for method of fabricating nano wire and nano wire complex.
This patent application is currently assigned to LG INNOTEK CO., LTD.. The applicant listed for this patent is Kyoung Hoon Chai, Joon Rak Choi, Jong Woon Moon, Young Sun You. Invention is credited to Kyoung Hoon Chai, Joon Rak Choi, Jong Woon Moon, Young Sun You.
Application Number | 20140220341 14/128791 |
Document ID | / |
Family ID | 47423115 |
Filed Date | 2014-08-07 |
United States Patent
Application |
20140220341 |
Kind Code |
A1 |
Choi; Joon Rak ; et
al. |
August 7, 2014 |
METHOD OF FABRICATING NANO WIRE AND NANO WIRE COMPLEX
Abstract
Disclosed are a method of fabricating a nano wire and a nano
wire complex. The method of fabricating a nano wire includes
forming a plurality of seed particles by allowing a first ion to
react with a second ion in a solvent, and forming a metallic nano
wire by adding and heating a metallic compound in the solvent.
Inventors: |
Choi; Joon Rak; (Seoul,
KR) ; Moon; Jong Woon; (Seoul, KR) ; You;
Young Sun; (Seoul, KR) ; Chai; Kyoung Hoon;
(Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Choi; Joon Rak
Moon; Jong Woon
You; Young Sun
Chai; Kyoung Hoon |
Seoul
Seoul
Seoul
Seoul |
|
KR
KR
KR
KR |
|
|
Assignee: |
LG INNOTEK CO., LTD.
Seoul
KR
|
Family ID: |
47423115 |
Appl. No.: |
14/128791 |
Filed: |
June 25, 2012 |
PCT Filed: |
June 25, 2012 |
PCT NO: |
PCT/KR2012/004977 |
371 Date: |
April 7, 2014 |
Current U.S.
Class: |
428/372 ;
75/343 |
Current CPC
Class: |
B22F 1/0025 20130101;
B22F 2009/245 20130101; Y10T 428/2927 20150115; B22F 9/24 20130101;
B22F 2301/255 20130101; B82Y 30/00 20130101; B82Y 40/00
20130101 |
Class at
Publication: |
428/372 ;
75/343 |
International
Class: |
B22F 9/24 20060101
B22F009/24 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 23, 2011 |
KR |
10-2011-0061028 |
Claims
1. A method of fabricating a nano wire, the method comprising:
forming a plurality of seed particles by allowing a first ion to
react with a second ion in a solvent; and forming a metallic nano
wire by adding and heating a metallic compound in the solvent.
2. The method of claim 1, wherein the seed particles have a
diameter in a range of 5 nm to 10nm.
3. The method of claim 1, wherein the first ion is a metallic ion,
and the second ion is a halogen ion.
4. The method of claim 1, wherein the seed particles include a
metal equal to a metal constituting the metallic compound.
5. The method of claim 1, wherein the seed particles and the
metallic compound include silver.
6. The method of claim 1, wherein the seed particles include silver
chloride.
7. A nano wire complex comprising: a metallic nano wire; and a seed
particle bonded with the metallic nano wire, wherein the seed
particle has a diameter in a range of 5 nm to 100 nm.
8. The nano wire complex of claim 7, wherein the seed particle is
provided in the metallic nano wire.
9. The nano wire complex of claim 7, wherein the seed particle is
provided at one end of the metallic nano wire.
10. The nano wire complex of claim 7, wherein the seed particle
includes chloride.
11. The nano wire complex of claim 10, wherein the metallic nano
wire includes silver, and the seed particle includes silver
chloride.
Description
TECHNICAL FIELD
[0001] The embodiment relates to a method of fabricating a nano
wire and a nano wire complex.
BACKGROUND ART
[0002] A transparent electrode including transparent material has
been applied to various electronic products such as a display
device, a solar cell, and a mobile device. Researches and studies
on a nano wire, which has a wire-shape structure in a nano-meter
size, as the transparent conductive material for the transparent
electrode, have been actively carried out.
[0003] Since the nano wire has superior electrical conductivity,
flexibility, and transmittance, the transparent electrode can
represent superior characteristics. However, nano wires are easily
aggregated during the reaction process, so that nano-particles are
formed. Accordingly, the nano wire may not be easily fabricated. As
a result, the product yield of the nano wire is significantly
lowered to about 10%, so that the practical use of the nano wire
may be difficult. Further, materials such as catalysts used to
accelerate the reaction of forming the nano wire remain on the
surface of the nano wire, so that the surface oxidation or the
surface corrosion of the nano wire may occur, or the electrical
conductivity may be degraded.
DISCLOSURE OF INVENTION
Technical Problem
[0004] The embodiment provides a long thin wire.
Solution to Problem
[0005] A method of fabricating a nano wire according to the
embodiment includes forming a plurality of seed particles by
allowing a first ion to react with a second ion in a solvent, and
forming a metallic nano wire by adding and heating a metallic
compound in the solvent.
[0006] According to the embodiment, the first ion may be a metallic
ion, and the second ion may be a halogen ion.
[0007] According to the embodiment, the seed particles may include
a metal equal to a metal constituting the metallic compound.
[0008] According to the embodiment, the seed particles and the
metallic compound may include silver.
[0009] According to the embodiment, the seed particles may include
silver chloride.
[0010] According to the embodiment, a nano wire complex includes a
metallic nano wire, and a seed particle bonded to the metallic nano
wire. The seed particle has a diameter in a range of 5 nm to 100
nm.
[0011] According to the embodiment, the seed particle is provided
in the metallic nano wire or provided at one end of the metallic
nano wire.
Advantageous Effects of Invention
[0012] As described above, according to the method of fabricating
the nano wire of the embodiment, after forming the seed particles
from the solvent, the metallic nano wire is formed by using the
seed particles. In this case, according to the method of
fabricating the nano wire of the embodiment, the diameter of the
seed particles can be properly adjusted. For example, the seed
particles may have a very small diameter of about 5 nm to about 100
nm.
[0013] In this case, the metallic nano wire may be grown from the
seed particles. Since the seed particles have a very small
diameter, the metallic nano wire may have very thin diameter.
BRIEF DESCRIPTION OF DRAWINGS
[0014] FIG. 1 is a block diagram showing a method of fabricating a
nano wire according to the embodiment;
[0015] FIG. 2 is a view showing a nano wire complex according to
the embodiment; and
[0016] FIG. 3 is a view showing another example of a nano wire
complex.
MODE FOR THE INVENTION
[0017] A method of fabricating a nano wire of the embodiment
includes a step of forming a plurality of seed particles by
allowing first ions to react to second ions in a solvent and a step
of forming a metallic nano wire by adding a metallic compound to
the solvent and heating the solvent having the metallic compound
added thereto.
[0018] In addition, the first ions may include metallic ions, and
the second ions may include halogen ions.
[0019] In addition, the seed particles and the metallic compound
may include the same metal.
[0020] Further, the seed particles and the metallic compound may
include silver (Ag).
[0021] In addition, the seed particles may include silver chloride
(AgCl).
[0022] Besides, each seed particle may have a diameter of about 5
nm to about 100 nm.
[0023] Hereinafter, the disclosure will be described in detail with
reference to accompanying drawings.
[0024] FIG. 1 is a flowchart chart showing the method of
fabricating the nano wire according to the embodiment.
[0025] Referring to FIG. 1, a method for manufacturing a nano wire
according to the disclosure may include a step of heating a solvent
(step ST10), a step of adding a capping agent to the solvent (step
ST20), a step of forming a plurality of seed particles in the
solvent (step ST30), a step of adding a fourth metallic compound to
the solvent (step ST40), a step of adding a room-temperature
solvent to the solvent (step ST50), and a step of refining a nano
wire (step ST60). The steps are not essential steps, parts of the
steps may not be performed according to the manufacturing method,
and the sequence of the steps may be changed. Hereinafter, each
step will be described in more detail.
[0026] According to the step of heating a solvent (step ST10), the
solvent is heated at the reaction temperature suitable for forming
the metallic nano wire.
[0027] The solvent may include polyol. The polyol serves as a mild
reducing agent while serving as a solvent of mixing different
materials, so that the polyol helps the formation of the metallic
nano wire. For example, the polyol may include ethylene glycol
(EG), propylene glycol (PG), glycerine, glycerol, or glucose. The
reaction temperature may be variously adjusted by taking the types
and the characteristics of solvents and the metallic compounds into
consideration.
[0028] For example, if a silver nano wire is formed by using
propylene glycol (PG) representing superior reduction power as a
solvent, the reaction temperature may be in the range of about
80.degree. C. to 140.degree. C. If the reaction temperature is less
than 80.degree. C., the reaction speed is reduced, so that reaction
may not smoothly occur, and the fabricating time may be increased.
If the reaction temperature exceeds 140.degree. C., the silver nano
wire may not be formed due to the aggregation phenomenon, and the
product yield may be degraded.
[0029] As described above, according to the present embodiment, the
silver nano wire may be fabricated at a reaction temperature lower
than the reaction temperature (e.g., 160.degree. C.) according to
the related art by using propylene glycol (PG) representing
superior reduction power. According to the related art, since the
reaction temperature is high, silver nano wires having a short
length (e.g., less than 5 .mu.m), which is disadvantageous when
forming a network structure, may be formed, and the product yield
of the silver nano wires may be lowered. In contrast, according to
the present embodiment, silver nano wires having a length of 20
.mu.m or more can be fabricated at a high product yield by reducing
the reaction temperature.
[0030] Thereafter, according to the step of adding the capping
agent to the solvent (step ST20), the capping agent inducing the
forming of the wire is added to the solvent. If reduction for the
forming of the nano wire is rapidly performed, metals are
aggregated, so that the forming of the nano wire may be difficult.
Accordingly, the capping agent prevents the metals from being
aggregated by properly dispersing materials contained in the
solvent.
[0031] The capping agent may include various materials. For
example, the capping agent may include material selected from the
group consisting of polyvinylpyrrolidone (PVP), polyvinyl alcohol
(PVA), cetyl trimethyl ammonium bromide (CTAB), cetyl trimethyl
ammonium chloride (CTAC), and polyacrylamide (PAA).
[0032] Then, according to the step of forming the seed particles in
the solvent (step ST30), first and second metallic compounds are
added to the solvent. Accordingly, first ions contained in the
first metallic compounds may react to second ions contained in the
second metallic compounds, thereby forming the seed particles. In
this case, the first ions may react to the second ions to form a
third metallic compound, and the seed particles may include the
third metallic compound.
[0033] The first ions may include metallic ions. In more detail,
the first ions may include gold ions, silver ions, platinum ions,
or palladium ions
[0034] The second ions may include halogen ions. In more detail,
the second ions may include chorine ions, bromide ions, or iodide
ions.
[0035] In other words, the third metallic compound contained in the
seed particles may be expressed in following chemical formula
1.
Chemical Formula 1
[0036] MX
[0037] In this case, X represents Cl, Br, or I, and M represents
Au, Ag, Pt, or Pd.
[0038] The third metallic compound may have very low solubility
with respect to the solvent. Accordingly, the third metallic
compound is extruded from the solvent and constitutes the seed
particles.
[0039] The seed particles may have a very small diameter. The seed
particles may have the diameter in the range of about 1 nm to about
1 .mu.m. In more detail, the seed particles may have the diameter
in the range of about 5 nm to about 100 nm. The above seed
particles may be uniformly dispersed in the solvent.
[0040] The molar ratio of the second metallic compound to the first
metallic compound may be about 1:1. In addition, the first metallic
compound may be added to the solvent with the content of about
0.0001 wt % to about 0.3 wt %. Further, the second metallic
compound may be added to the solvent with the content of about
0.0001wt % to about 0.3 wt %.
[0041] The first metallic compound may include salts including the
first ions. In addition, the first metallic compound may include
nitrates. In more detail, the first metallic compound may include
silver nitrate.
[0042] The second metallic compound may include salts including the
second ions. In addition, the second metallic compound may include
sodium salts. In more detail, the second metallic compound may
include sodium chloride.
[0043] Thereafter, in the step of adding a fourth metallic compound
to the solvent (step ST40), a reaction solution is prepared by
adding the fourth metallic compound to the solvent.
[0044] In this case, the fourth metallic compound melt in an
additional solvent may be added to a solvent having the capping
agent added thereto and the seed particles provided therein. The
additional solvent may include the same material as that
constituting an initial solvent or a material different from that
constituting the initial solvent. In addition, the fourth metallic
compound may be added after a predetermined time elapses from time
at which the seed particles are formed. Accordingly, the
temperature can be stabilized to a proper reaction temperature.
[0045] In this case, the fourth metallic compound may include metal
used to form a metallic nano wire to be fabricated. In order to
form silver nano wire, the metallic compound may include
AgNO.sub.3, or KAg(CN).sub.2.
[0046] As described above, if the fourth metallic compound is added
to the solvent including the capping agent and the seed particles,
reaction occurs so that the fabrication of the metallic nano wire
is started. In this case, the metallic nano wire may be grown from
the seed particles. In other words, metal extruded by reducing the
fourth metallic compound is grown from each seed particle to form
the metallic nano wire.
[0047] In this case, since the seed particles have a very small
diameter, the metallic nano wire may be grown with a small
diameter.
[0048] After the metallic nano wire has been completely grown, the
seed particles may be removed through the following processes such
as a refining process. In other words, in the following processes,
the seed particles may be separated from the metallic nano wire and
removed.
[0049] However, a portion of the seed particles may remain.
Accordingly, a portion of the third metallic compound may be
detected from the metallic nano wire according to the present
embodiment.
[0050] In other words, the seed particles may be bonded with the
metallic nano wire thereby forming a nano wire complex.
[0051] FIG. 2 is a view showing the nano wire complex according to
the embodiment. FIG. 3 is a view showing another nano wire
complex.
[0052] As shown in FIGS. 2 and 3, portions of the metallic nano
wire may have the form a nano wire complex 10 or 11. The seed
particles 100 are bonded with the metallic nano wire 200. The ratio
of the metallic nano wire representing the form of the nano wire
complex 10 or 11 may be about 0.1% to about 0.001%.
[0053] In particular, as shown in FIG. 2, the seed particles 100
may be provided at one end of the metallic nano wire 200. In
addition, as shown in FIG. 3, seed particles 110 may be provided in
the metallic nano wire 200.
[0054] In this case, as described above, the diameters of the seed
particles 100 and 110 may be in the range of about 1 nm to about 1
.mu.m, in more detail, the range of about 5 nm to about 100 nm. In
more detail, the diameters of the seed particles 110 and 110 may be
in the range of about 10 nm to about 50 nm. As described above,
when the seed particles 100 and 110 having a very small diameter
are detected, the metallic nano wire having a small diameter is
formed through the fabricating method according to the present
embodiment.
[0055] According to the present embodiment, 60 weight part to 330
weight part of the capping agent may be added based on 100 weight
part of the metallic compound such as AgNO.sub.3, or KAg(CN).sub.2.
If less than 60 weight part of the capping agent is added, the
aggregation phenomenon can be sufficiently prevented. If over 330
weight part of the capping agent is added, metallic nano particles
having a spherical shape or a cubic shape may be formed, and the
capping agent remains in the fabricated metallic nano wire, so that
the electrical conductivity of the metallic nano wire may be
degraded.
[0056] In addition, the first and second metallic compounds may
have the content in the range of 0.00001 weight part to 0.5 weight
part based on 100 weight part of the fourth metallic compound. If
less than 0.00001 weight part of the first and second metallic
compounds is added, the reaction may not be sufficiently
accelerated. In addition, if over 0.5 weight part of the first and
second metallic compounds is added, silver is rapidly reduced so
that silver nano particles are generated or the nano wire may have
a thick diameter and a short length. In addition, catalyst remains
in the metallic nano wire so that the electrical conductivity may
be degraded.
[0057] Thereafter, according to the step of adding the
room-temperature solvent to the solvent (step ST50), the
room-temperature solvent is added to the solvent in which reaction
is started. The room-temperature solvent may include a material
identical to or different from a material used in the initial
stage. For example, the room-temperature solvent may include polyol
such as ethylene glycol and propylene glycol.
[0058] As the solvent, in which the reaction is started, is
continuously heated in order to maintain the constant reaction
temperature, the temperature may be increased in the process of the
reaction. As described above, the reaction temperature may be more
constantly maintained by temporarily degrading the temperature of
the solvent by adding the room-temperature solvent to the solvent
in which the reaction is started.
[0059] The step of adding the room-temperature solvent (step ST50)
may be performed one time or several times by taking the reaction
time, and the temperature of the reaction solution into
consideration.
[0060] Thereafter, in the step of refining the nano wire (step
ST60), the metallic nano wire is refined and collected in the
reaction solution.
[0061] In more detail, if acetone serving as a non-polar solvent is
added to the reaction solution instead of water, the metallic nano
wire is deposited at the lower portion of the solution due to the
capping agent remaining on the surface of the metallic nano wire.
This is because the capping agent is not dissolved in the acetone,
but aggregated and deposited although the capping agent is
sufficiently dissolved in the solvent. Thereafter, when the upper
portion of the solution is discarded, a portion of the capping
agent and nano particles are discarded.
[0062] If distill water is added to the remaining solution,
metallic nano wire and metallic nano particles are dispersed. In
addition, if acetone is more added, the metallic nano wire is
deposited, and the metallic nano particles are dispersed in the
upper portion of the solution. Thereafter, if the upper portion of
the solution is discarded, a part of the capping agent and the
aggregated metallic nano particles are discarded. After collecting
the metallic nano wire by repeatedly performing the above
processes, the metallic nano wire is stored in the distill water.
The metallic nano wire can be prevented from being re-aggregated by
storing the metallic nano wire into the distill water.
[0063] As described above, according to the method of fabricating
the metallic nano wire of the embodiment, the metallic nano wire is
grown by using seed particles having a very small diameter.
Accordingly, the metallic nano wire having a small diameter can be
formed.
EXPERIMENTAL EXAMPLE
[0064] 200 ml of propylene glycol was heated at a temperature of
126.degree. C., and 6.7 g of polyvinylpyrrolidone and 0.1 g of
potassium bromide were added and melted. Thereafter, 0.35 mmol of
sodium salt and 0.35 mmol of AgNO.sub.3 were added to form the seed
particles. After about 10 mins were elapsed, 2.3 g of AgNO.sub.3
was melted in 100 ml of propylene glycol and added to a solution
containing the polyvinylpyrrolidone and the seed particles. Then,
the reaction was continued for about 2 hours, so that the
fabrication of the silver nano wire was finished.
[0065] After the solution, which had been subject to the reaction,
was diluted by using 500 ml of acetone, 600 ml of acetone was added
to the diluted solution. Then, the upper portion of the solution
having propylene glycol, and silver nano particles dispersed
therein was discarded. After repeatedly performing the above
processes three times, the result was stored in 10 ml of distill
water.
COMPARATIVE EXAMPLE
[0066] Different from the experimental example, silver chloride
particles having the average diameter of about 2.5 .mu.m were added
to the solvent instead of forming seed particles through the
reaction between sodium salt and silver nitrate. Remaining
procedures were performed in the same manner as that of the
experimental example.
Result
[0067] As shown in Table 1, a thinner and longer silver nano wire
was formed in the experimental example.
TABLE-US-00001 TABLE 1 average diameter(nm) average length(.mu.m)
Experimental Example 45 22 Comparative Example 65 20
[0068] Any reference in this specification to "one embodiment," "an
embodiment," "example embodiment," etc., means that a particular
feature, structure, or characteristic described in connection with
the embodiment is included in at least one embodiment of the
invention. The appearances of such phrases in various places in the
specification are not necessarily all referring to the same
embodiment. Further, when a particular feature, structure, or
characteristic is described in connection with any embodiment, it
is submitted that it is within the purview of one skilled in the
art to effect such feature, structure, or characteristic in
connection with other ones of the embodiments.
[0069] Although embodiments have been described with reference to a
number of illustrative embodiments thereof, it should be understood
that numerous other modifications and embodiments can be devised by
those skilled in the art that will fall within the spirit and scope
of the principles of this disclosure. More particularly, various
variations and modifications are possible in the component parts
and/or arrangements of the subject combination arrangement within
the scope of the disclosure, the drawings and the appended claims.
In addition to variations and modifications in the component parts
and/or arrangements, alternative uses will also be apparent to
those skilled in the art.
* * * * *