KR20230173408A - Triple frame nanoparticles and manufacturing method thereof - Google Patents

Abstract

The present invention can provide triple frame nanoparticles and a method for manufacturing the same according to an embodiment, and triple frame nanoparticles in which multiple nanoparticles are integrated in one space through the formation of a thin film layer by the Kirkendall process and an elaborate chemical reaction in an aqueous solution. can be manufactured. In addition, the triple frame nanoparticles have a larger hot spot area than existing single or double nanostructures, so the Raman signal of single particle surface-enhanced Raman scattering is increased by 15 times, increasing the resolution of the single particle surface-enhanced Raman signal. There is an effect that can dramatically improve.

Description

Triple frame nanoparticles and manufacturing method thereof}

The present invention relates to triple frame nanoparticles, and more specifically, to a method of synthesizing triple frame nanoparticles using the Kirkendall effect and an aqueous solution etching method, and to a surface enhanced Raman scattering analysis method using triple frame nanoparticles.

Precious metal nanoparticles (gold, silver, copper nanoparticles) are frequently used in surface-enhanced Raman scattering techniques due to the local surface plasmon resonance phenomenon that occurs in the noble metal nanoparticles. The surface-enhanced Raman scattering technique is an ultra-sensitive analysis technique that enables detection of single molecules and is widely used in fields such as life science, chemical production, and environmental management.

At this time, the electromagnetic field near the noble metal nanoparticles is maximized between the narrow gaps between the noble metal nanoparticles, also called hot spots, and as a result, the Raman scattering signal of the target molecule can be amplified.

To create hot spots from noble metal nanoparticles, nanoparticles are controlled to have gaps between particles, or particles with gaps within a single particle, rough surfaces, or porous structures are synthesized. In particular, particles with gaps inside the particles are synthesized. Synthesis of particles allows for uniform control of the size of the hot spot, improving sensitivity and reproducibility when applied to surface-enhanced Raman analysis.

DNA or polymers with sulfur functional groups are used to synthesize nanoparticles so that there are gaps within the particles. Alternatively, particles with a porous structure have a high density of hot spots and can be used in surface-enhanced Raman scattering analysis, or have a large surface area to volume ratio and can be used in catalysts, plasma etching methods, acid dealloying corrosion methods, and galvanic substitution reactions. A porous structure can be synthesized using the method.

Because changes in the shape of metal nanoparticles can lead to changes in the electrical and optical properties of metal nanoparticles, research on synthesizing various shapes of metal nanoparticles is active.

In particular, the nanoframe structure has a larger surface area than the nanoparticle structure and can smoothly interact with external light, so it is widely used in catalysts, surface-enhanced Raman scattering, and medical fields. To synthesize the nanoframe structure, Lithography and galvanic substitution methods are mainly used.

Republic of Korea Public Patent No. 10-2018-0065493

In order to solve the problems of the prior art as described above, the technical problem to be achieved by the present invention is to provide triple frame nanoparticles and a method of manufacturing the same.

In addition, the triple frame nanoparticles can precisely control their internal spacing and shape, maximizing interaction with light to provide a surface-enhanced Raman scattering substrate that can be used in applied research such as bio and chemical detection. .

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

In order to achieve the above technical problem, an embodiment of the present invention provides a method for manufacturing triple frame nanoparticles.

A triple frame nanoparticle manufacturing method according to an embodiment of the present invention includes preparing a single frame made of gold or platinum with a closed loop structure; forming a first ring structure with a silver thin film layer by concentrically growing silver nanoparticles on the single frame; Gold nanoparticles are formed on the first ring structure, and the silver thin film layer is transformed into a gold-silver alloy layer spaced apart from the single frame by performing a Kirkendall process, with the inner and inner sides based on the single frame. forming a second ring structure by forming a gold-silver alloy layer in which the thickness of the layer formed on the outer side is thicker than the thickness of the layer formed on the upper and lower sides; and the gold-silver alloy layer of the second ring structure It may include forming triple frame nanoparticles with nanogaps by etching them in an aqueous solution to remove the upper and lower regions.

Additionally, in the step of preparing a single frame made of gold or platinum according to an embodiment of the present invention, the gold single frame may have a structure in which a gold thin film is formed on a platinum single frame having a closed loop structure.

Additionally, in the step of forming the second ring structure according to an embodiment of the present invention, the Kirkendall process may be performed in an aqueous solution containing trivalent gold ions, a reducing agent, and a stabilizer.

Additionally, in the step of forming the triple frame nanoparticle according to an embodiment of the present invention, the etching may be performed in an aqueous solution containing trivalent gold ions and a stabilizer.

Additionally, in the step of forming the triple frame nanoparticle according to an embodiment of the present invention, the gold-silver alloy layer may be transformed into a gold thin film layer during the etching process.

In order to achieve the above technical problem, another embodiment of the present invention provides triple frame nanoparticles.

The triple frame nanoparticles are characterized in that they are manufactured by the triple frame nanoparticle manufacturing method described above.

The triple frame nanoparticles may be connected by at least one gold bridge.

Additionally, according to an embodiment of the present invention, the spacing between nanogaps of the triple frame nanoparticles may be 7 nm to 23 nm.

Additionally, according to one embodiment of the present invention, the diameter of the triple frame nanoparticle may be 148 nm to 194 nm.

Additionally, according to an embodiment of the present invention, the triple frame nanoparticles have a symmetrical geometry, and through the symmetrical geometry, Raman scattering of light of near-infrared wavelengths in all directions may be possible.

In order to achieve the above technical problem, another embodiment of the present invention provides a substrate for surface-enhanced Raman scattering.

The substrate for surface-enhanced Raman scattering according to an embodiment of the present invention may include triple-frame nanoparticles manufactured by the triple-frame nanoparticle production method described above.

According to one embodiment of the present invention, triple frame nanoparticles in which multiple nanoparticles are integrated in one space can be manufactured by forming a thin film layer by the Kirkendall process and performing a sophisticated chemical reaction in an aqueous solution.

In addition, the triple frame nanoparticles have a larger hot spot area than existing single or double nanostructures, so the Raman signal of single particle surface-enhanced Raman scattering is increased by 15 times, increasing the resolution of the single particle surface-enhanced Raman signal. There is an effect that can dramatically improve.

In addition, the single particle surface-enhanced Raman scattering signal detected from the triple frame nanoparticle has high reproducibility and has the effect of showing uniform Raman signal and high resolution regardless of the direction of light.

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

Figure 1 is a schematic diagram showing triple frame nanoparticles and their manufacturing method according to an embodiment of the present invention.
Figure 2 is a flow chart showing a method for manufacturing triple frame nanoparticles according to an embodiment of the present invention.
Figure 3 is a schematic diagram of the etching process of triple frame nanoparticles according to an embodiment of the present invention.
Figure 4 is a plan view showing triple frame nanoparticles according to an embodiment of the present invention.
Figure 5 is a cross-sectional view showing a triple frame nanoparticle according to an embodiment of the present invention.
Figure 6 is an SEM image of (C) a single frame nanoparticle made of platinum, (D) a first ring structure, (E) a second ring structure, and (F) a triple frame nanoparticle according to an embodiment of the present invention.
Figure 7 is a visible-near-infrared optical spectrum graph of platinum single-frame nanoparticles, first ring structures, second ring structures, and triple-frame nanoparticles according to an embodiment of the present invention.
Figure 8 is a TEM image and an EDS mapping image of (A, B) gold-platinum-gold triple frame nanoparticles according to an embodiment of the present invention.
Figure 9 is a schematic diagram and graph showing the near-field electromagnetic field aggregation effect through measuring the spacing and surface enhanced Raman scattering of gold-platinum-gold triple frame nanoparticles according to an embodiment of the present invention.
Figure 10 is a schematic diagram and graph showing the characteristics of gold-gold-gold triple frame nanoparticles and the near-field electromagnetic field aggregation effect through surface-enhanced Raman scattering measurement according to an embodiment of the present invention.

Hereinafter, the present invention will be described with reference to the attached drawings. However, the present invention may be implemented in various different forms and, therefore, is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts that are not related to the description are omitted, and similar parts are given similar reference numerals throughout the specification.

Throughout the specification, when a part is said to be "connected (connected, contacted, combined)" with another part, this means not only "directly connected" but also "indirectly connected" with another member in between. "Includes cases where it is. In addition, when a part is said to “include” a certain component, this does not mean that other components are excluded, but that other components can be added, unless specifically stated to the contrary.

The terms used herein are only used to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as “comprise” or “have” are intended to indicate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Hereinafter, triple frame nanoparticles according to an embodiment of the present invention will be described in detail with reference to the attached drawings.

Hereinafter, a method for manufacturing triple frame nanoparticles according to an embodiment of the present invention will be described in detail with reference to the attached drawings.

Referring to Figures 1 to 3, a method for manufacturing triple frame nanoparticles will be described.

Figure 1 is a schematic diagram showing triple frame nanoparticles and their manufacturing method according to an embodiment of the present invention.

Figure 2 is a flow chart showing a method for manufacturing triple frame nanoparticles according to an embodiment of the present invention.

Figure 3 is a schematic diagram of the etching process of triple frame nanoparticles according to an embodiment of the present invention.

The triple frame nanoparticle manufacturing method according to an embodiment of the present invention includes preparing a single frame (100, 110) made of gold or platinum with a closed loop structure (S100);

Concentrically growing silver nanoparticles on the single frames 100 and 110 to form first ring structures 200 and 210 with silver thin film layers 201 and 211 (S200);

Gold nanoparticles are formed on the first ring structures 200 and 210, and the silver thin film layer is transformed into gold-silver alloy layers 301 and 311 spaced apart from the single frame by performing a Kirkendall process. Based on the step (S300) of forming the second ring structures (300,310) by forming gold-silver alloy layers (301,311) where the thickness of the layers formed on the inner and outer sides is thicker than the thickness of the layers formed on the upper and lower sides. );and

A step (S400) of forming triple frame nanoparticles (400,410) with nanogaps by etching them in an aqueous solution to remove the upper and lower regions of the gold-silver alloy layers (301,311) of the second ring structures (300,310). It can be included.

The first step may include preparing a single frame (100, 110) made of gold or platinum. (S100)

At this time, in the case of the single frame made of gold, the gold single frame 110 can be prepared by concentrically growing a gold thin film on the platinum single frame 100.

That is, the single frame according to an embodiment of the present invention can use platinum as a starting material, and the reason why platinum was selected as a starting material is because platinum has high structural stability and can be used as an excellent internal support.

In the second step, it may include concentrically growing silver nanoparticles on the single frames 100 and 110 to form first ring structures 200 and 210 in which silver thin film layers 201 and 211 are formed. (S200)

In this specification, “concentric growth” means that when nanoparticles grow along a closed-loop single frame, growth progresses on both the inner and outer boundaries of the closed-loop single frame, thereby forming a closed-loop type. It can refer to a growth method in which nanoparticles grow non-selectively and evenly along a single frame.

At this time, the concentric growth occurs when the potential applied during the reduction reaction is higher than both the surface energy of the inner boundary (E _inner -boundary) and the surface energy of the outer boundary (E _outer -boundary). A reduction reaction may occur at both the internal and external boundaries to form a silver thin film.

For example, according to an embodiment of the present invention, when forming a silver thin film on a platinum single frame 100, CTAC (hexadecyltrimethylammonium chloride), a silver precursor containing Ag ⁺ _, NaOH, and AA (ascorbic acid) are used. The platinum single frame 100 is added to a solution containing silver and concentric growth is performed to form a silver thin film layer, thereby forming the first ring structure 200. At this time, the detailed method of forming the silver thin film layer will be described later in the following examples.

In addition, when forming a silver thin film on the gold single frame 110, the first ring structure 210 is formed by forming the silver thin film layer in the same manner as in the case of forming the silver thin film on the platinum single frame 100. can do.

At this time, the reason for forming the silver thin film layer on the platinum single frame is to create a second ring structure through the Kirkendall process between the silver thin film layer and the gold thin film layer subsequently stacked thereon.

In the third step, gold nanoparticles are formed on the first ring structure, and the silver thin film layer is transformed into a gold-silver alloy layer spaced apart from the single frame by performing a Kirkendall process, based on the single frame. This may include forming a gold-silver alloy layer in which the thickness of the layers formed on the inner and outer sides is thicker than the thickness of the layers formed on the upper and lower sides to form a second ring structure. (S300)

The second ring structure includes preparing a mixed solution containing gold ions, a reducing agent, and a surfactant consisting of CTAC (hexadecyltrimethylammonium chloride); It can be manufactured by performing the step of adding the first ring structure to the mixed solution.

The solution providing trivalent gold ions is preferably HAuCl ₄ ·nH2O or HAuCl ₄ solution, but is not limited thereto.

Referring to FIG. 3, the second ring structures 300 and 310 will be described in detail.

Figure 3 is a schematic diagram of the etching process of triple frame nanoparticles according to an embodiment of the present invention.

Referring to FIG. 3(a), it can be seen that the gold-silver alloy layers 301 and 311 have empty spaces formed on the single frames 100 and 110, and the gold-silver alloy layers 301 and 311 are formed on the inner and outer sides of the single frame. The thickness of the silver alloy layer may be thicker than the thickness of the gold-silver alloy layer formed on the upper and lower sides.

At this time, in order to form a gold-silver alloy layer while forming an empty space on the single frame, a galvanic substitution reaction and a Kirkendall process must be performed. The galvanic substitution reaction involves a metal ion having a higher reduction potential than itself. As an electrochemical reaction that occurs when silver is added to Au ³⁺ cations or Pt ⁴⁺ cations, a galvanic substitution reaction proceeds, for example, a reaction shown in Scheme 1 or Scheme 2 below.

[Reaction Formula 1]

The X is a halogen element.

[Scheme 2]

When using the galvanic substitution reaction, while 3 equivalents of Ag(s) are oxidized and dissolved, only 1 equivalent of Au(s) is reduced. That is, as the galvanic substitution reaction progresses, the oxidation rate of silver becomes faster, so vacancies are created in the entire metal mixture, and ultimately holes are created, forming a void structure.

In addition, the Kirkendall process refers to the effect on movement at the interface between metal atoms, and the direction in which the alloy moves is in a direction that minimizes surface energy. That is, in an alloy where silver and gold are mixed, the surface energy of silver is smaller than that of gold, so the silver inside the mixture moves to the surface.

Considering the galvanic substitution reaction and the Kirkendall effect together, in an alloy containing a mixture of silver and gold, the silver is continuously dissolved by gold ions through a galvanic substitution reaction, and gold nanoparticles will take its place. At this time, due to the Kirkendall effect, the gold nanoparticles move back to the center of the alloy, and the silver atoms inside the alloy move to the surface of the alloy.

The silver atoms that have moved to the surface of the alloy in this way will be able to proceed again with a galvanic substitution reaction, and this reaction is repeated, so that the second ring structure of the present invention is a gold-silver alloy layer with an empty space formed on the single frame (100, 110). (301,311) can be formed.

In the fourth step, it may include forming triple frame nanoparticles with nanogaps by etching them in an aqueous solution to remove the upper and lower regions of the gold-silver alloy layer of the second ring structure (S400).

Preparing a mixed solution containing the triple frame nanoparticles and a surfactant composed of CTAC (hexadecyltrimethylammonium chloride) and gold ions; It may include adding the second ring structure to the mixed solution and etching it.

The gold-silver alloy layer of the second ring structures 301 and 311 has a characteristic in which the thickness of the gold-silver alloy layer formed on the inner and outer sides is thicker than the thickness of the gold-silver alloy layer formed on the upper and lower sides. .

At this time, by the etching process, the inner, outer, upper, and lower sides of the gold-silver alloy layer can all be etched at the same speed, and the gold-silver alloy layer formed on the upper and lower sides is formed on the inner and outer sides. Because it is thinner than the gold-silver alloy layer formed on the side, the gold-silver alloy layer on the upper and lower sides is etched and removed, and the gold-silver alloy layer on the inner and outer sides is etched at the same rate and remains. .

Describing in detail with reference to FIG. 3, the gold-silver alloy layer of FIG. 3(a) formed with a non-uniform thickness can be uniformly etched using the following Chemical Formulas 1 and 2.

[Formula 1]

2Au(s)+AuCl ₄ ^- (aq)+2Cl ^- (aq) → 3AuCl ₂ ^- (aq)

[Formula 2]

3Ag(s)+AuCl ₄ ^- (aq)→ Au(s)+3Ag ⁺ (aq)+4Cl ^- (aq)

When using the etching reaction using the aqueous solution, referring to Chemical Formula 1, it can be confirmed that 2 equivalents of Au(s) are oxidized and dissolved. Additionally, referring to Chemical Formula 2, while 3 equivalents of Ag(s) are oxidized and dissolved, only 1 equivalent of Au(s) is reduced.

That is, as the redox reaction progresses, the oxidation rate of silver is faster and the rate of reduction of gold is slower, making it possible to etch the gold-silver alloy layer of the entire second ring frame.

When etching is continued as shown in FIGS. 3(b) and 3(c), triple frame nanoparticles having a gold-platinum-gold structure can be ultimately formed as shown in FIG. 3(d).

At this time, when the concentration of gold ions required for etching, the temperature for etching, and the time for etching are simultaneously adjusted in the etching process, the gold-silver alloy layer on the inner and outer sides remains and the upper and lower sides remain. The gold-silver alloy layer can be etched to form triple frame nanoparticles.

Accordingly, the frames remaining on the inside can become internal frames (401 and 411), and the frames remaining on the outside can become external frames (403 and 413).

Referring to FIG. 2, the upper and lower sides of the existing gold-silver alloy layer are etched, and the inner frame and outer frame are residual after a certain portion of the gold-silver alloy layer is etched, so the inner frame and outer frame are based on the ring frame. It may be a single-walled tube shape with a curved surface structure bent outward.

Accordingly, the triple frame nanoparticle has a closed loop structure and includes ring frames 402 and 412 made of gold or platinum; Gold inner frames 401 and 411 in the shape of a single-walled tube located inside the ring frame and having a closed loop structure and a curved surface structure bent outward with respect to the ring frame; and a gold outer frame (403, 413) located outside the ring frame, having a closed loop structure and a single-wall tube shape having a curved surface structure bent outward with respect to the ring frame, between the ring frame and the inner frame. And there may be a nano gap between the ring frame and the external frame.

Therefore, by using the above triple-frame nanoparticle manufacturing method, triple-frame nanoparticles in which multiple nanoparticles are integrated in one space can be manufactured by forming a thin film layer by the Kirkendall process in an aqueous solution and performing a sophisticated chemical reaction in the aqueous solution.

In addition, by the method of manufacturing triple frame nanoparticles, more hot spot areas are formed within the triple frame nanoparticles than in existing single or double nano structures, so that the Raman signal of single particle surface-enhanced Raman scattering is increased by 15 times. This has the effect of dramatically improving the resolution of single particle surface-enhanced Raman signals.

In addition, the single particle surface-enhanced Raman scattering signal detected from the triple frame nanoparticle has high reproducibility, the Raman signal is uniform regardless of the direction of light, and can exhibit high resolution.

With reference to FIGS. 4 to 5, triple frame nanoparticles will be described.

Figure 4 is a plan view showing triple frame nanoparticles according to an embodiment of the present invention.

Additionally, Figure 5 is a cross-sectional view showing a triple frame nanoparticle according to an embodiment of the present invention.

Referring to Figure 4, triple frame nanoparticles according to an embodiment of the present invention can be manufactured by the triple frame nanoparticle manufacturing method described above, and have a closed loop structure and ring frames 402 and 412 made of gold or platinum. ); Gold inner frames 401, 411 in the shape of a single-walled tube, located inside the ring frame, have a closed loop structure, and have a curved surface structure bent outward with respect to the ring frame; And a gold outer frame (403, 413) located outside the ring frame, has a closed loop structure, and has a single-wall tube shape with a curved surface structure bent outward with respect to the ring frame, and the ring frame (402, 412) and the inner frames 401 and 411, and between the ring frames 402 and 412 and the outer frames 403 and 413, there is a nano gap.

At this time, the inner frames 401 and 411 and the outer frames 403 and 413 may be connected by at least one gold bridge.

First, the triple frame nanoparticle according to an embodiment of the present invention includes a ring frame 402.

The ring frame may be in the form of a ring with a closed loop structure and may be made of gold (412) or platinum (402).

At this time, if the ring frame is made of gold 412, it may have a structure in which a gold thin film is grown on a single platinum frame.

That is, platinum of the ring frame according to an embodiment of the present invention can be used as a starting material, and the reason why platinum was selected as a starting material is that platinum has high structural stability and can be used as an excellent internal support.

The ring frames 402 and 412 may have a diameter of 100 nm to 110 nm. Specifically, the ring frame 402 made of platinum may have a diameter of 100 nm to 110 nm, and the ring frame 412 made of gold may have a diameter of 100 nm to 110 nm. The diameter may be 110 nm to 120 nm.

Additionally, the triple frame nanoparticle according to an embodiment of the present invention may include gold internal frames 401 and 411.

The gold inner frame is located inside the ring frame, has a closed loop structure, and may be in the shape of a single-walled tube having a curved structure bent outward with respect to the ring frame.

Referring to FIG. 4, when the triple frame nanoparticles 400 and 410 are viewed from above, it can be seen that the gold inner frame has a circular structure and a hollow structure is formed inside.

In addition, referring to the side cross-sectional view of the figure, it can be seen that the gold inner frame is located inside the ring frame, has a closed loop structure, and has a single-wall tube shape with a curved surface structure bent outward with respect to the ring frame.

At this time, the spacing between the nano gaps between the ring frames 402 and 412 and the internal frames 401 and 411 may be 7 nm to 23 nm.

The gap between the inner frame and the ring frame is formed by the Kirkendall process, and the size of the nanogap of the triple frame nanoparticle can be adjusted by adjusting the thickness of the silver thin film layer in the silver thin film layer forming step (S200).

In addition, referring to FIG. 5, the size of the nano gap of the triple frame nanoparticle 410 including the gold ring frame 412 is the nano gap of the triple frame nanoparticle 400 including the platinum ring frame 402. You can see that it is smaller than the size of .

Additionally, the triple frame nanoparticle according to an embodiment of the present invention may include gold outer frames 401 and 411.

Referring to the side cross-sectional view of FIG. 5, it can be seen that the gold outer frame is located outside the ring frame, has a closed loop structure, and has a single-walled tube shape with a curved surface structure bent outward with respect to the ring frame. .

At this time, the spacing of the nano gap between the ring frames 402 and 412 and the internal frames 401 and 411 may be 7 nm to 23 nm.

Since the triple frame nanoparticles (400, 410) according to an embodiment of the present invention have a symmetrical geometry, the gap between the ring frames (402, 412) and the inner frames (401, 411) is the ring frame (402) , 412) and the outer frames 403 and 413 may have the same spacing.

Additionally, referring to Figure 5, the thickness of the outer frame 403 of the triple frame nanoparticle 400 including a platinum ring frame is 15 nm, and the outer frame of the triple frame nanoparticle 410 including a gold ring frame ( 413) can be confirmed to have a thickness of 15 nm.

Figure 5 is a schematic diagram showing the cross-sectional structure of the triple frame nanoparticle according to an embodiment of the present invention when viewed from the side.

Referring to FIG. 5, it can be seen that the diameter of the triple frame nanoparticle including the platinum ring frame is 154 nm, and the diameter of the triple frame nanoparticle including the gold ring frame is 156 nm.

In addition, since the cross-sectional diameter of the platinum single frame 402 is 15 nm and the cross-sectional diameter of the gold single frame 412 is 20 nm, it is confirmed that the cross-sectional diameter of the gold single frame 412 is 5 nm thicker than that of the platinum single frame 402. can do.

In addition, it can be seen that the inner frames 401 and 411 and the outer frames 403 and 413 have a single-walled tube shape with a curved surface structure bent outward with respect to the ring frame.

At this time, when the ring frame 402 is made of platinum, the hollow size between the inner frames 401 is 24 nm, and when the ring frame 412 is made of gold, the hollow size between the inner frames 402 is 24 nm. can do.

At this time, since the triple frame nanoparticle has a symmetrical geometry, the spacing between the ring frame and the inner frame may be the same as the spacing between the ring frame and the outer frame.

Referring to FIG. 5, the gap between the inner frame or outer frame of the triple frame nanoparticle including the platinum ring frame and the ring frame is 10 nm, and the inner frame or outer frame of the triple frame nanoparticle including the gold ring frame is 10 nm. It can be seen that the gap between and ring frame is 8nm.

At this time, when the ring frame is made of platinum, the spacing of the nano gap between the ring frame 402 and the internal frame 401 is the nano gap between the ring frame 402 and the internal frame 401 when the ring frame is gold. It can be seen that it is relatively larger than the interval of .

Therefore, triple-frame nanoparticles when the ring frame is gold may have better near-field aggregation properties than triple-frame nanoparticles when the ring frame is platinum.

The thickness of the internal frame can control the concentration of gold ions in the aqueous solution, the concentration of the gold ion reducing agent, and the time of the process (S300) of growing gold ions on the silver thin film layer. The specific method is described in the description of the triple frame nanoparticle manufacturing method. This will be described later.

Additionally, a surface-enhanced Raman scattering substrate according to an embodiment of the present invention will be described.

The surface-enhanced Raman scattering substrate may include triple-frame nanoparticles manufactured by a triple-frame nanoparticle manufacturing method.

In this way, the triple frame nanoparticle forms two circular hot spots that can maximize the near-field electromagnetic field, allowing it to display a high-resolution single particle surface-enhanced Raman signal regardless of the direction of light.

As the distance between the inner frame and the outer frame of this single particle surface enhanced Raman signal is reduced, the single particle surface enhanced Raman efficiency can be increased by more than 15 times compared to the existing double nanoring structure.

Manufacturing example 1

First, a single frame made of platinum with a diameter of 110 nm was prepared.

Next, 0.5 mL of 0.1 M Hexadecyltrimethylammonium chloride (CTAC), 20 μL of 50 mM sodium hydroxide, and 200 μL of 0.2 mM silver nitrate solution were added to the platinum single frame as a metal nanoparticle stabilizer, and 40 μL of 10 mM ascorbic acid was added to the vial. After addition, the solution was maintained at 30°C for 30 minutes to form a silver thin film, thereby forming the first ring structure.

Next, 25 ㎕ of 10 mM ascorbic acid in 0.5 ml of 0.1 M hexadecyltrimethylammonium chloride (CTAC) aqueous solution as a metal nanoparticle stabilizer and 25 ㎕ of 0.2 mM HAuCl ₄ aqueous solution as a gold precursor were subjected to the Kirkendall process at 30 °C for 15 minutes. A second ring structure was formed.

Next, the second ring structure was added to a mixed solution containing 0.5 ml of 0.1 M hexadecyltrimethylammonium chloride (CTAC) aqueous solution as a metal nanoparticle stabilizer and 100 ㎕ of 0.2 mM HAuCl ₄ aqueous solution as a gold precursor and maintained at 30°C for 15 minutes. It was etched to form a triple frame structure.

Manufacturing example 2

First, a single frame made of platinum with a diameter of 110 nm was prepared.

Next, 0.5 mL of 50mM Hexadecyltrimethylammonium bromide (CTAB) as a metal nanoparticle stabilizer, 40μL of 1mM HAuCl ₄ aqueous solution as a gold precursor, and 40μL of 100mM ascorbic acid were added to the platinum single frame, and then the solution was heated to 30°C. It was maintained for 30 minutes to form a gold thin film to form a gold single frame.

Next, 0.5 mL of 0.1 M Hexadecyltrimethylammonium chloride (CTAC), 40 μL of 50 mM sodium hydroxide, and 360 μL of 0.2 mM silver nitrate solution were added to the gold single frame as a metal nanoparticle stabilizer, and 80 μL of 10 mM ascorbic acid was added. Afterwards, the solution was maintained at 30°C for 30 minutes to form a silver thin film, thereby forming the first ring structure.

Next, 25 ㎕ of 10 mM ascorbic acid in 0.5 ml of 0.1 M hexadecyltrimethylammonium chloride (CTAC) aqueous solution as a metal nanoparticle stabilizer and 25 ㎕ of 0.2 mM HAuCl ₄ aqueous solution as a gold precursor were subjected to the Kirkendall process at 30 °C for 15 minutes. A second ring structure was formed.

Next, the second ring structure was added to a mixed solution containing 0.5 ml of 0.1 M hexadecyltrimethylammonium chloride (CTAC) aqueous solution as a metal nanoparticle stabilizer and 300 ㎕ of 0.2 mM HAuCl ₄ aqueous solution as a gold precursor and maintained at 30°C for 15 minutes. It was etched to form a triple frame structure.

Experiment example

Figure 6 is an SEM image of (C) a single frame nanoparticle made of platinum, (D) a first ring structure, (E) a second ring structure, and (F) a triple frame nanoparticle according to an embodiment of the present invention.

Referring to FIG. 6 (D), it can be seen that silver nanoparticles grow concentrically on the single frame nanoparticle made of platinum to form a silver thin film layer, and referring to FIG. 6 (E), the silver thin film layer It can be confirmed that gold nanoparticles are formed spaced apart from the single frame, forming a second ring structure transformed into a gold-silver alloy layer.

In addition, Figure 6 (F) shows that the upper and lower regions of the gold-silver alloy layer of the second ring structure were removed to form triple frame nanoparticles with nanogaps.

Figure 7 is a visible-near-infrared optical spectrum graph of platinum single-frame nanoparticles, first ring structures, second ring structures, and triple-frame nanoparticles according to an embodiment of the present invention.

Referring to FIG. 7, since a peak was formed at the wavelength of 385, it can be confirmed that a silver thin film layer was formed on the single frame nanoparticle made of platinum, and since a peak was formed at a wavelength of 420 nm, it can be confirmed that gold nanoparticles were formed on the silver thin film layer. It can be confirmed that was formed.

Additionally, since a peak was formed at a wavelength of 1060 nm, it can be confirmed that gold-platinum-gold triple frame nanoparticles were formed.

Figure 8 is a TEM image and an EDS mapping image of (A, B) gold-platinum-gold triple frame nanoparticles according to an embodiment of the present invention.

Referring to Figure 8 (A), it can be seen that the diameter of the gold-platinum-gold triple frame nanoparticle according to an embodiment of the present invention is 165 nm.

Additionally, referring to Figure 8 (B), it can be seen that it contains 76% gold (Au), 19% silver (Ag), and 5% platinum (Pt).

Figure 9 is a schematic diagram and graph showing the near-field electromagnetic field aggregation effect through measuring the spacing and surface enhanced Raman scattering of gold-platinum-gold triple frame nanoparticles according to an embodiment of the present invention.

Figure 9 (A) is a schematic diagram showing the spacing of triple frame nanoparticles with a gold-platinum-gold structure, and Figure 9 (B) is a SEM image, TEM, of triple frame nanoparticles with a gold-platinum-gold structure. Figure 9(C) is a histogram of size information of triple frame nanoparticles with a gold-platinum-gold structure, and Figure 9(D) is a surface-enhanced Raman measurement of triple frame nanoparticles with a gold-platinum-gold structure. It is a spectrum graph.

Referring to Figures 9 (A, B, C) of Figure 9, it can be seen that the size of the triple frame nanoparticles of the gold-platinum-gold structure is adjusted, and the size of the nano gap of the triple frame nanoparticles is 9 nm. to 23 nm, the diameter of the triple frame is 148 nm to 194 nm, and the thickness of the external frame is 13 nm to 20 nm. Referring to Figure 9(D) of Figure 9, it can be seen that triple frame nanoparticles with a gold-platinum-gold structure have a near-field aggregation effect at the single particle level, showing a surface-enhanced Raman scattering signal at the single particle level. .

Figure 10 is a schematic diagram and graph showing the characteristics of gold-gold-gold triple frame nanoparticles and the near-field electromagnetic field aggregation effect through surface-enhanced Raman scattering measurement according to an embodiment of the present invention.

Figure 10(A) is a schematic diagram showing the manufacturing method of gold-gold-gold triple frame nanoparticles, and Figure 10(B) is a schematic diagram showing the size of the nanogap interval of triple frame nanoparticles containing a gold single frame. and a graph, Figure 10 (C) is an SEM image that confirms the actual shape of the triple frame nanoparticle containing a gold single frame, and Figure 10 (D) is a graph showing the wavelength of the triple frame nanoparticle containing a gold single frame. This is a graph showing the visible-near-infrared optical spectrum.

In addition, Figure 10 (E) is a TEM image (top) and EDS mapping image (bottom) that can confirm the microstructure and element distribution of the triple frame nanoparticles containing the gold single frame, and Figure 10 (F) is This is a graph showing the single particle surface enhanced Raman scattering signal of triple frame nanoparticles with a gold-gold-gold structure.

Referring to FIG. 10 (A), the manufacturing method of gold-gold-gold triple frame nanoparticles can be confirmed as a schematic diagram, and referring to FIG. 10 (B), the size of the nano gap of the triple frame nanoparticle is 7 nm. to 9 nm, the diameter of the gold single frame is 22 nm to 28 nm, and the thickness of the external frame is 12 nm to 14 nm.

Additionally, referring to FIG. 10 (C), it can be seen that the triple frame nanoparticle according to an embodiment of the present invention forms two nanogaps.

In addition, referring to Figure 10 (D), it can be confirmed that the triple frame nanoparticles are made of gold because they show a peak at 518 nm.

In addition, referring to FIG. 10 (E), it can be confirmed that the triple frame nanoparticles contain gold, silver, and platinum through the graph located in the lower part of FIG. 10 (E), and the upper part of FIG. 10 (F) It can be confirmed that a gap structure has been formed through the TEM image located in .

Additionally, referring to FIG. 10(F), it can be seen that the gold-gold-gold structured triple frame nanoparticles exhibit a surface-enhanced Raman scattering signal at the single particle level.

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

The scope of the present invention is indicated by the patent claims described below, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

100: Platinum single frame
110, 111: Gold single frame
200,210: First ring structure
201, 211: silver thin film layer
300,310: 2nd ring structure
301, 311: Gold thin film layer
400, 410: triple frame nanoparticles
401, 411: inner frame
402, 412: Ring frame
403, 413: external frame

Claims (11)

Preparing a single frame made of gold or platinum with a closed loop structure;
forming a first ring structure with a silver thin film layer by concentrically growing silver nanoparticles on the single frame;
Gold nanoparticles are formed on the first ring structure, and the silver thin film layer is transformed into a gold-silver alloy layer spaced apart from the single frame by performing a Kirkendall process, with the inner and inner sides based on the single frame. Forming a second ring structure by forming a gold-silver alloy layer in which the thickness of the layer formed on the outer side is thicker than the thickness of the layer formed on the upper and lower sides; And
A triple frame nanoparticle manufacturing method comprising the step of forming triple frame nanoparticles having a nanogap by etching in an aqueous solution to remove the upper and lower regions of the gold-silver alloy layer of the second ring structure. . According to paragraph 1,
In the step of preparing a single frame made of gold or platinum,
The gold single frame is a triple frame nanoparticle manufacturing method, characterized in that the gold thin film is formed on a platinum single frame having a closed loop structure. According to paragraph 1,
In the step of forming the second ring structure,
The Kirkendall process is a method of producing triple frame nanoparticles, characterized in that it is performed in an aqueous solution containing trivalent gold ions, a reducing agent, and a stabilizer. According to paragraph 1,
In the step of forming the triple frame nanoparticles,
A triple frame nanoparticle manufacturing method, characterized in that the etching is performed in an aqueous solution containing trivalent gold ions and a stabilizer. According to paragraph 1,
In the step of forming the triple frame nanoparticles,
A triple frame nanoparticle manufacturing method, characterized in that the gold-silver alloy layer is transformed into a gold thin film layer during the etching process. Triple frame nanoparticles, characterized in that manufactured by the triple frame nanoparticle production method of claim 1. According to clause 6,
The triple frame nanoparticle is characterized in that the triple frame nanoparticle is connected by at least one gold bridge. According to clause 6,
A triple frame nanoparticle, characterized in that the spacing of nanogaps of the triple frame nanoparticle is 7nm to 23nm. According to clause 6,
Triple frame nanoparticles, characterized in that the diameter of the triple frame nanoparticles is 148 nm to 194 nm. According to clause 6,
The triple frame nanoparticle has a symmetrical geometry, and is capable of Raman scattering of light of near-infrared wavelengths in all directions through the symmetrical geometry. A substrate for surface-enhanced Raman scattering, comprising triple-frame nanoparticles manufactured by the triple-frame nanoparticle production method of claim 1.

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