Hierarchical cube-on-cube-shaped plasmonic n-type semiconductor nanocrystals on dopant surface

Abstract

The present invention comprises: a method for preparing nanocrystals; ITO nanocrystals and a core-shell-structured FITO as products using same; and a method for preparing and depositing FITO nanocrystals that can be deposited in a single layer. According to the present invention, the method for preparing ITO nanocrystals comprises a step of highly-efficiently preparing ITO nanocrystals by using a mixture comprising indium acetate and a tin compound, and a method for preparing a core-shell-structured FITO coats FITO core particles with indium, thereby producing stable FITO nanocrystals having high durability even in extreme environments. In addition, the method for depositing FITO comprises injecting FITO on a polar solution so as to implement uniform monolayer deposition through phase separation and self-assembly, thereby enabling precise fine patterning. Therefore, the present invention efficiently produces a high-performance nanomaterial, thereby providing a technical advantage suitable for various industrial applications such as smart windows, highly durable materials and precision electronic and optical devices.

Description

Hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystals on the dopant surface

[0001] The present invention relates to hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystals on a dopant surface, and more particularly, to the technical field of synthesis and deposition of ITO (Indium Tin Oxide) and FITO (Fluorine-doped Indium Tin Oxide) nanocrystals. The purpose of the present invention is to provide a nanomaterial that can be effectively utilized in various semiconductor and electromagnetic applications as well as in areas requiring high-performance optical filtering by optimizing the infrared plasmonic properties and structural properties of the nanocrystals.

[0002]

[0003] Existing synthesis and deposition methods for ITO and FITO nanocrystals have presented several challenges in achieving mass production, uniform monolayer formation, and material savings, all of which are essential for high-performance infrared plasmonic materials. First, the ITO synthesis process relies on expensive imported raw materials and small quantities of synthesis solutions, making mass production difficult. Furthermore, the long synthesis time and high cost pose challenges for applications requiring mass production. Consequently, a new manufacturing method utilizing large reactors to reduce production time and costs has been required.

[0004] In addition, existing deposition technologies such as drop casting and spin coating have limitations in forming a thick film in multiple layers or having non-uniform light absorption characteristics because it is difficult to form a uniform monolayer film. Although the drop casting method is simple, it forms a thick film, making it difficult to manufacture a precise monolayer film. In addition, the spin coating method has problems in that the coating solution splashes out due to centrifugal force, causing material loss and making it difficult to maintain a uniform monolayer. In particular, the existing spin coating cannot deposit FITO nanocrystals in a monolayer with a regular arrangement, so the plasmonic performance cannot be implemented uniformly.

[0005] Additionally, while regular nanoparticle arrangement is crucial for applications leveraging infrared absorption and plasmonic properties, conventional methods have struggled to achieve this arrangement reliably, making them unsuitable for applications requiring high plasmonic performance and optical control. Self-assembly-based deposition methods are required, enabling the implementation of precise structures, such as micropatterning.

[0006] The prior art document of the present invention is disclosed in Korean Patent No. 10-1752541 (June 23, 2017).

[0007]

[0008] The purpose of the present invention is to solve existing problems and provide an improved method for manufacturing and utilizing nanocrystals. Another object of the present invention is to provide a method for manufacturing FITO, a method for manufacturing core-shell structured FITO and ITO nanocrystals, ITO nanocrystals manufactured thereby, and a method for depositing FITO.

[0009]

[0010] In order to achieve the above technical task, one embodiment of the present invention regarding hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystals on a dopant surface may be characterized by including the steps of: adding a first solution of a mixture of indium acetate (In(ac)3) and a tin compound and oleic acid into a first reactor; flowing nitrogen gas into the first reactor and then forming a vacuum state inside the first reactor; stirring the first solution at 120 to 150°C and 500 to 700 rpm for 20 to 40 minutes; extracting the stirred first solution and transferring it to a second reactor at a temperature of 230 to 320°C at a rate of 0.1 to 0.3 ml / min, and then mixing oleyl alcohol to form a second solution; and cooling the second solution to room temperature.

[0011] In one embodiment of the present invention, the first solution may be characterized by including indium acetate (In(ac)3), a tin compound, and oleic acid in a weight ratio of 1300 to 1400:80 to 95:10.

[0012] In one embodiment of the present invention, the first reactor and the second reactor may be characterized by having a volume of 10 ml to 10 L.

[0013] In one embodiment of the present invention, the method may include continuously supplying a mixture of indium acetate and a tin compound to the first reactor.

[0014] In one embodiment of the present invention, the tin compound may be characterized as being tin acetate (Sn(ac)4) or stannous chloride pentahydrate (SnCl4 · 5H2O), and may include 1 to 15 wt% of the tin compound and the remainder being indium acetate.

[0015] In one embodiment of the present invention, the method may further include a step of mixing the cooled second solution with isopropyl alcohol (IPA) and centrifuging the mixture after the step of cooling the second solution to room temperature, a step of redispersing the centrifuged material with hexane, and a step of mixing the redispersed material with the isopropyl alcohol and centrifuging the mixture again.

[0016] In one embodiment of the present invention, the step of redispersing and the step of centrifuging may be repeated two or more times.

[0017] In one embodiment of the present invention, in the hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystals of any one of the dopant surfaces of one embodiment for carrying out the present invention, the solution of the nanocrystals may be characterized in that it has a volume of 10 ml to 10 L, and the electron concentration of the nanocrystals may be characterized in that it has a range of 1.00 X 1020 to 1.00 X 1025.

[0018] In one embodiment of the present invention, the method may be characterized by including a step of synthesizing FITO (F,Sn:In2O3, Fluorine Indium Tin Oxide) core particles having a tin (Sn) content of 2 to 10 wt% in a hierarchical cube-on-cube shape plasmonic n-type semiconductor nanocrystal on a dopant surface, and a step of coating indium on the FITO core particles.

[0019] In one embodiment of the present invention, the step of manufacturing the FITO core particle may be characterized by including a step of mixing Sn(ac), SnF4, In(ac) and oleic acid to prepare a first solution, a step of mixing the first solution with oleyl alcohol heated to a temperature of 230 to 320°C to prepare a second solution, and a step of centrifuging the second solution to prepare a third solution.

[0020] In one embodiment of the present invention, the step of preparing the first solution may be characterized by including the steps of measuring Sn(ac), SnF4, In(ac), and oleic acid in a ratio of 0.35 to 2:1:25 to 30 and placing them in a spherical body, flowing nitrogen (N2) gas into the spherical body to form a vacuum in the spherical body, heating the spherical body at 100 to 150°C for 10 to 20 minutes in a vacuum, and flowing nitrogen (N2) gas into the spherical body and placing the solution in a container.

[0021] In one embodiment of the present invention, the step of preparing the second solution includes the steps of injecting oleyl alcohol into a three-necked flask and forming a vacuum state, heating the three-necked flask to a temperature of 230 to 320°C while flowing nitrogen gas into the three-necked flask, injecting the first solution into the three-necked flask at a constant rate when the temperature of the oleyl alcohol is 230 to 320°C, cooling the three-necked flask to 80 to 100°C, and centrifuging the solution in the three-necked flask to obtain the second solution. In the case of the centrifugation, the step may include adding hexane.

[0022] In one embodiment of the present invention, the step of coating the indium may include a step of mixing the third solution and oleyl alcohol to prepare a fourth solution, a step of mixing indium acetate and oleic acid with the fourth solution to prepare a fifth solution, a step of heating the fifth solution at 100 to 150°C for 10 to 20 minutes, a step of cooling the fifth solution in a three-necked flask to a range of 80 to 100°C, a step of mixing the cooled fifth solution with isopropyl to prepare a sixth solution, and a step of centrifuging the sixth solution to obtain FITO having a core-shell structure, wherein the step may include adding isopropyl alcohol and hexane when centrifuging the sixth solution.

[0023] In one embodiment of the present invention, in the hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystals of the dopant surface of the core-shell structure manufactured by any one of the methods of one embodiment of the present invention, the size of the FITO core particles is 10 to 20 nm, and the size of the FITO shell particles is 20 to 40 nm, and the product may be characterized by having a shape that changes from a uniform shelling to a hierarchical shelling as the tin content increases.

[0024] In one embodiment of the present invention, the hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystals on the surface of the dopant include the steps of preparing a polar solution such as dimethylformamide (DMF) or water, and the steps of injecting FITO (F,Sn:In2O3, Fluorine Indium Tin Oxide) onto the polar solution and self-assembling through phase separation, wherein the self-assembling step is characterized in that indium oxide (In2O3) and tin oxide (SnO2) self-assemble while phase separation occurs on the polar solution, and may include the steps of adjusting the concentration of the FITO solution by adding a polar solvent or an organic solvent such as hexane that enables phase separation.

[0025] In one embodiment of the present invention, the hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystals on the dopant surface may be characterized by the steps of preparing a substrate inside a container, immersing the substrate in a polar solution such as DMF (dimethylformamide) or water, injecting FITO (F,Sn:In2O3, Fluorine Indium Tin Oxide) onto the polar solution, and removing the polar solution using heat treatment.

[0026] In one embodiment of the present invention, the step of removing the polar solution may include a step of heating the substrate at 100 to 200°C for 20 to 60 minutes.

[0027] In one embodiment of the present invention, the step of injecting FITO may be characterized by including a step of controlling the FITO concentration by an organic solvent such as a polar solvent or hexane that enables phase separation.

[0028] In one embodiment of the present invention, the hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystals on the surface of the dopant by any one of the methods of one embodiment of the present invention may be characterized by a substrate on which FITO is deposited in a single layer and a FITO product manufactured.

[0029]

[0030] According to embodiments of the present invention, the core-shell structure of FITO improves durability by providing higher resistance to extreme environments than conventional FITO. Furthermore, the ability to fabricate diverse geometric nanoparticles with plasmonic properties expands the scope of plasmonic applications. This enables diverse high-functionality applications, such as photocatalysis.

[0031] According to embodiments of the present invention, mass production of ITO nanocrystals is possible using a large-scale reactor, and manufacturing costs are reduced by using domestic raw materials. The large quantities of ITO nanocrystals produced in this manner can be utilized in large-scale applications such as smart windows.

[0032] Furthermore, according to embodiments of the present invention, precise micropatterning is enabled by self-assembling FITO into a uniform monolayer, and precise self-assembly is realized by preventing side reactions through phase separation and self-assembly processes in polar solutions such as DMF. Furthermore, by minimizing FITO solution loss during the deposition process, material waste can be reduced and efficiency can be increased.

[0033] Further scope of the applicability of the present invention will become apparent from the detailed description below. However, since various modifications and variations within the spirit and scope of the present invention will become apparent to those skilled in the art, it should be understood that the detailed description and specific examples, such as preferred embodiments of the present invention, are given by way of example only.

[0034] 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 detailed description of the present invention or the composition of the invention described in the claims.

[0035]

[0036] Figure 1 is a flowchart showing a manufacturing process of ITO nanocrystals related to one embodiment of the present invention.

[0037] Figure 2 is a flowchart showing a dispersion process of ITO nanocrystals related to one embodiment of the present invention.

[0038] Figure 3 is a schematic diagram of an ITO manufacturing device related to one embodiment of the present invention.

[0039] Figure 4 is an infrared absorption spectrum of ITO related to one embodiment of the present invention.

[0040] Figure 5 is an SEM photograph of ITO related to one embodiment of the present invention.

[0041] Figure 6 is a flowchart showing a FITO manufacturing process related to one embodiment of the present invention.

[0042] Figure 7 is a flowchart showing a manufacturing process of a FITO core related to one embodiment of the present invention.

[0043] Figure 8 is a flowchart showing a manufacturing process of a first solution related to one embodiment of the present invention.

[0044] Figure 9 is a flowchart showing a manufacturing process of a second solution related to one embodiment of the present invention.

[0045] Figure 10 is a flowchart showing a process for coating indium according to one embodiment of the present invention.

[0046] FIG. 11 is a TEM image of FITO containing 4% tin according to one embodiment of the present invention.

[0047] FIG. 12 is a TEM photograph of a FITO core containing 1% tin, 4% tin, and 5% tin according to one embodiment of the present invention.

[0048] FIG. 13 is a TEM image of FITO having a core-shell structure containing 1% tin, 4% tin, and 5% tin according to one embodiment of the present invention.

[0049] FIG. 14 is a graph showing the size distribution of cores and shells containing 1% tin, 4% tin, and 5% tin in accordance with one embodiment of the present invention.

[0050] Figure 15 is a conceptual diagram of a uniform shell structure related to one embodiment of the present invention.

[0051] Figure 16 is a conceptual diagram of a hierarchical shell structure related to one embodiment of the present invention.

[0052] FIG. 17 is an FTIR analysis graph of a core and shell containing 1% tin, 4% tin, and 5% tin according to one embodiment of the present invention.

[0053] Figure 18 is a flowchart showing a FITO manufacturing process related to one embodiment of the present invention.

[0054] Figure 19 is a flowchart showing a FITO deposition process related to one embodiment of the present invention.

[0055] Figure 20 is a schematic diagram of a FITO deposition process related to one embodiment of the present invention.

[0056] Figure 21 is a TEM image of FITO formed as a single layer according to one embodiment of the present invention.

[0057]

[0058] Hereinafter, the present invention will be described with reference to the attached drawings. However, the present invention can be implemented in various different forms and is therefore not limited to the embodiments described herein. In the drawings, irrelevant parts have been omitted for clarity of description, and similar parts have been designated with similar reference numerals throughout the specification.

[0059] Throughout the specification, when a part is said to be "connected (connected, contacted, or coupled)" to another part, this includes not only cases where it is "directly connected," but also cases where it is "indirectly connected" with another part in between. Furthermore, when a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0060] The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this specification, it should be understood that the terms "comprises" or "has" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0061] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0062] One embodiment of the present invention relates to a method for producing ITO nanocrystals, which can synthesize a larger quantity of ITO, an infrared plasmonic nano-semiconductor material, using a large-scale reactor, and to ITO nanocrystals produced thereby. This method reduces the time required to synthesize ITO, and enables mass production scale-up from 10 mL to 10 L volumes.

[0063] FIG. 1 is a flowchart showing a manufacturing process of ITO nanocrystals related to one embodiment of the present invention, FIG. 2 is a flowchart showing a dispersion process of ITO nanocrystals related to one embodiment of the present invention, and FIG. 3 is a schematic diagram of an ITO manufacturing apparatus related to one embodiment of the present invention. Hereinafter, a method for manufacturing ITO nanocrystals according to one embodiment of the present invention will be described with reference to FIGS. 1 to 3.

[0064] First, referring to FIG. 1, a method for manufacturing ITO nanocrystals in one embodiment of the present invention includes a step (S110) of adding a first solution containing a mixture of indium acetate (In(ac)3) and a tin compound and oleic acid to a first reactor, a step (S120) of forming a vacuum state inside the first reactor after flowing nitrogen gas into the first reactor, a step (S130) of stirring the first solution, a step (S140) of extracting the stirred first solution and transferring it to a second reactor, and then mixing oleyl alcohol to form a second solution, and a step (S150) of cooling the second solution to room temperature. At this time, the tin compound may be tin acetate (Sn(ac)4) or stannous chloride pentahydrate (SnCl4 5H2O). For example, the indium acetate may be a 99% solution, the tin acetate may be a 99.99% solution, and the stannous chloride pentahydrate may be a 95% solution.

[0065] In one embodiment of the present invention, a three-necked flask is used, and a thermometer (111) for measuring the temperature inside the reactor is connected to three holes of the three-necked flask, a Schlenk line (113) that can supply nitrogen, an inert gas, or be connected to a vacuum pump to suck in the air inside, and a syringe (115) that can inject or extract another solution is provided. At this time, a manifold port valve is provided to the Schlenk line (113), and two pipes are connected to the valve, and the inert gas can be blown in by turning the valve in one direction or air can be sucked in by turning it in the opposite direction.

[0066] In addition, in one embodiment of the present invention, a cation doping element is used to form a semiconductor-type plasmonic nanocrystal, and the cation is tin (Sn). In the mixture, the tin compound is 1 to 15 wt%, and the remainder is indium acetate. If the doping tin (Sn) content exceeds 15%, the material is defined as an alloy, and phase separation may occur in which free electrons are not formed, which may result in a decrease in infrared absorption performance. That is, the concentration of free electrons is reduced, and the peak shift of the localized surface plasmon resonance (LSPR) may redshift to a long wavelength region, resulting in a decrease in performance. Therefore, the content of the doping element in one embodiment of the present invention is limited to 15% or less.

[0067] And, in the step of stirring the first solution, the solution is heated to a temperature range of 120 to 150°C using a heating mantle (120), and stirred for 20 to 40 minutes at 500 to 700 rpm using a stirrer (130). Thereafter, the speed of extracting the stirred first solution and transferring it to the second reactor is set to 0.1 to 0.3 ml / min. At this time, the transfer of the first solution may be performed using a syringe (115), but is not limited thereto, and the first solution may be transferred from the first reactor to the second reactor by connecting the first reactor and the second reactor through a tube or the like. The first reactor and the second reactor may have the same structure and the same size, but are not necessarily limited thereto.

[0068] In addition, the temperature of the second reactor is set to 230 to 320°C. If it is lower than 230°C, the synthesis may not occur properly, and if it exceeds 320°C, the solvent may not be able to withstand it, so the heating temperature of the first solution is limited as above.

[0069] Meanwhile, in one embodiment of the present invention, after the step of cooling the second solution to room temperature (S150), the method further includes the step of mixing the cooled second solution with isopropyl alcohol (IPA) and centrifuging (S160), the step of redispersing the centrifuged material with hexane (S170), and the step of mixing the redispersed material with the isopropyl alcohol and centrifuging again (S180). This is to ensure proper dispersion. In addition, the step of redispersing (S170) and the step of centrifuging again (S180) may be repeated two or more times (S190).

[0070] In one embodiment of the present invention, ITO nanocrystals having a volume of about 10 mL to 10 L are manufactured, and for this purpose, a mixture of indium acetate and a tin compound is continuously supplied to the first reactor. In one embodiment of the present invention, a pump is used for continuous supply to enable continuous growth. That is, in one embodiment of the present invention, a base material including indium acetate and a tin compound is prepared, the base material is manufactured into a colloidal solution, and nucleation and growth are performed using a nanoparticle synthesis technique. At this time, a doping element (Sn) is injected into the solution to synthesize nanocrystals. Thereafter, the synthesized nanoparticles are separated and purified and dispersed in a polar solution or a non-polar solution, thereby manufacturing ITO nanocrystals.

[0071] Hereinafter, a method for manufacturing ITO nanocrystals according to one embodiment of the present invention will be described in more detail.

[0072] First, ITO nanocrystals are synthesized. Below is an experimental example.

[0073] <Experimental Example 1>

[0074] (1) A first solution containing indium acetate (In(ac)3) (1386.76 mg, 99%, Uniam), tin acetate (Sn(ac)4) (88.72 mg, 99.99%, Sigma Aldrich), and oleic acid (10 ml, 99%, Sigma Aldrich) is placed in a three-necked flask (110).

[0075] (2) After placing the three-necked flask (110) into the heater (120) (heating mantle), N2 gas is passed through the first solution.

[0076] (3) After creating a vacuum inside the three-neck flask (110), stir at 600 rpm at 120°C for 30 minutes in a vacuum state.

[0077] (4) Transfer the stirred first solution to a syringe (115) (19-gauge-needle) under a N2 gas flow.

[0078] (5) Add oleyl alcohol (13 ml, 75%, Daejung) to the second reactor.

[0079] (6) Add the first solution stirred at a rate of 0.2 ml / min to the second reactor maintained at 290 ℃.

[0080] (7) After the first solution injection is complete, slowly cool to room temperature.

[0081]

[0082] <Experimental Example 2>

[0083] (1) A first solution containing indium acetate (In(ac)3) (1386.76 mg, 99%, Uniam), stannous chloride pentahydrate (SnCl4 · 5H2O, SnCl4 Tin (IV) Chloride Pentahydrate) (87.65 mg, 95%, Junsei Chemical), and oleic acid (10 ml, 99%, Sigma Aldrich) is placed in a three-necked flask (110).

[0084] (2) After placing the three-necked flask (110) into the heater (120) (heating mantle), N2 gas is passed through the first solution.

[0085] (3) After creating a vacuum inside the three-neck flask (110), stir at 600 rpm at 120°C for 30 minutes in a vacuum state.

[0086] (4) Transfer the stirred first solution to a syringe (115) (19-gauge-needle) under a N2 gas flow.

[0087] (5) Add oleyl alcohol (13 ml, 75%, Daejung) to the second reactor.

[0088] *66(6) Add the first solution stirred at a rate of 0.2 ml / min to the second reactor maintained at 290 ℃.

[0089] (7) After the first solution injection is complete, slowly cool to room temperature.

[0090]

[0091] <Experimental Example 3>

[0092] (1) A first solution containing indium acetate (In(ac)3) (13.868 g, 99%, Uniam), stannous chloride pentahydrate (SnCl4 · 5H2O, SnCl4 Tin (IV) Chloride Pentahydrate) (876.5 mg, 95%, Junsei Chemical), and oleic acid (100 ml, 99%, Sigma Aldrich) is placed in a three-necked flask (110).

[0093] (2) After placing the three-necked flask (110) into the heater (120) (heating mantle), N2 gas is passed through the first solution.

[0094] (3) After creating a vacuum inside the three-neck flask (110), stir at 600 rpm at 120°C for 30 minutes in a vacuum state.

[0095] (4) Transfer the stirred first solution to a syringe (115) (19-gauge-needle) under a N2 gas flow.

[0096] (5) Add oleyl alcohol (13 ml, 75%, Daejung) to the second reactor.

[0097] (6) Add the first solution stirred at a rate of 0.2 ml / min to the second reactor maintained at 290 ℃.

[0098] (7) After the first solution injection is complete, slowly cool to room temperature.

[0099] At this time, the three-necked flask functions as a reactor in which ITO nanocrystals are synthesized.

[0100] Once the ITO nanocrystals are synthesized above, a dispersion process is performed to ensure good dispersion. The dispersion process is performed as follows.

[0101] (1) Add the synthesized material and isopropyl alcohol (IPA) in a 1:1 ratio, then centrifuge at 3600 rpm for 3 minutes.

[0102] (2) Redisperse the solid material in 15 ml of hexane, inject isopropyl alcohol in a 1:1 ratio, and then centrifuge.

[0103] (3) Repeat the above step (2) twice more.

[0104] (4) Collect the solution after centrifugation at 2000 rpm for 3 minutes with hexane.

[0105] ITO nanocrystals, which are infrared plasmonic nano semiconductor materials obtained through this process, have the characteristic of being able to absorb infrared rays, and their electron concentration ranges from 1.00 X 1020 to 1.00 X 1025. They can be synthesized using raw materials from domestic companies, which reduces the cost during synthesis. In addition, they can be synthesized in large quantities and used in smart windows that block infrared rays, which require a large amount of ITO nanocrystals.

[0106] In addition, as can be seen from the experimental example above, the first solution in one embodiment of the present invention has a weight ratio of indium acetate (In(ac)3), tin compound, and oleic acid of 1300 to 1400:80 to 95:10.

[0107] FIG. 4 is an infrared absorption spectrum of ITO according to an embodiment of the present invention, and FIG. 5 is an SEM photograph of ITO according to an embodiment of the present invention. The left graph of FIG. 4 is an infrared absorption spectrum according to the tin content of small ITO nanocrystals manufactured by a conventional method, and the right graph of FIG. 4 is an infrared absorption spectrum according to the tin content of ITO nanocrystals according to an embodiment of the present invention, and it can be seen that the infrared absorption wavelength bands are almost similar. In addition, the left photograph of FIG. 5 is an SEM photograph of small ITO nanocrystals manufactured by a conventional method, and the right photograph of FIG. 5 is an SEM photograph of ITO nanocrystals according to an embodiment of the present invention, and it can be seen that their structures and shapes are almost similar. Accordingly, it can be seen that there is almost no difference in the physical properties of ITO nanocrystals manufactured by a conventional method or a method according to an embodiment of the present invention.

[0108] One embodiment of the present invention relates to a method for manufacturing FITO (F,Sn:In2O3, Fluorine Indium Tin Oxide), which is a nanoparticle that absorbs infrared rays, and in particular, to a method for manufacturing FITO having a core-shell structure and FITO having a core-shell structure manufactured thereby.

[0109] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0110] First, FIG. 6 is a flowchart showing a FITO manufacturing process related to one embodiment of the present invention, FIG. 7 is a flowchart showing a FITO core manufacturing process related to one embodiment of the present invention, FIG. 8 is a flowchart showing a first solution manufacturing process related to one embodiment of the present invention, FIG. 9 is a flowchart showing a second solution manufacturing process related to one embodiment of the present invention, and FIG. 10 is a flowchart showing an indium coating process related to one embodiment of the present invention.

[0111] In one embodiment of the present invention, the core-shell structured FITO is manufactured by a method of forming an indium (In)-based shell on a tin (Sn)-based core FITO. That is, the FITO manufacturing method according to one embodiment of the present invention includes a step of synthesizing FITO (F,Sn:In2O3, Fluorine Indium Tin Oxide) core particles (S2110) and a step of coating indium on the FITO core particles (S2120).

[0112] At this time, the tin (Sn) content contained in the FITO is set to be 2 to 10 wt%. If the tin content is less than 2 wt%, the FITO core and shell grow separately, and if it exceeds 10 wt%, a new resulting material is generated. Therefore, in one embodiment of the present invention, the tin content is limited to 2 to 10 wt%. Preferably, tin can contain 4 wt%.

[0113] Referring to FIG. 7, the step of manufacturing the FITO core particle may include a step of mixing Sn(ac), SnF4, In(ac), and oleic acid to prepare a first solution (S2111), a step of mixing the first solution with oleyl alcohol heated to a temperature of 230 to 320°C to prepare a second solution (S2113), and a step of centrifuging the second solution to prepare a third solution (S2115). As such, in one embodiment of the present invention, the heating temperature of the first solution is limited to 230 to 320°C. If it exceeds 320°C, the solvent cannot withstand it, so the heating temperature of the first solution is limited as above.

[0114] At this time, the step of preparing the first solution includes a step of measuring Sn(ac), SnF4, In(ac), and oleic acid, placing them in a sieve, and mixing them (S21111), a step of flowing nitrogen (N2) gas into the sieve to form the sieve into a vacuum (S21112), a step of heating the sieve at 100 to 150°C for 10 to 20 minutes in a vacuum (S21113), and a step of flowing nitrogen (N2) gas into the sieve and placing the solution in a container (S21114).

[0115] In addition, as illustrated in FIG. 9, the step of preparing the second solution includes the steps of injecting oleyl alcohol into a three-necked flask and forming a vacuum state (S21131), heating the three-necked flask to a temperature of 230 to 320°C while flowing nitrogen gas into the three-necked flask (S21132), injecting the first solution into the three-necked flask at a constant ratio when the temperature of the oleyl alcohol is 230 to 320°C (S21133), cooling the three-necked flask to 80 to 100°C (S21134), and centrifuging the solution in the three-necked flask (S21135) to obtain the second solution. At this time, the centrifugation is performed by adding hexane, and the temperature in the heating step is limited to a range that the solvent can withstand, as described above.

[0116] Meanwhile, the step of coating the indium according to one embodiment of the present invention includes, as illustrated in FIG. 10, a step of mixing the third solution and oleyl alcohol to prepare a fourth solution (S2121), a step of mixing indium acetate and oleic acid with the fourth solution to prepare a fifth solution (S2123), a step of heating the fifth solution at 100 to 150°C for 10 to 20 minutes (S2125), a step of cooling the fifth solution in the three-necked flask to a range of 80 to 100°C (S2127), a step of mixing the cooled fifth solution with isopropyl to prepare a sixth solution (S2128), and a step of centrifuging the sixth solution (S2129) to obtain FITO having a core-shell structure. At this time, the sixth solution is centrifuged and isopropyl alcohol and hexane are added.

[0117] By this process, it is possible to manufacture FITO with a core-shell structure.

[0118] Hereinafter, a FITO manufacturing process according to one embodiment of the present invention will be described in more detail.

[0119] FITO core synthesis process

[0120] To synthesize a FITO core (cube) containing 4 wt% tin, weigh 0.07098 g of Sn(ac)4, 0.04868 g of SnF4, 1.32837 g of In(ac)3, and 10 mL of oleic acid and mix them in a triangular container. Place a magnetic bar in the center of the triangular container, insert a thermometer into the left hole, and a rubber stopper into the right hole to block the hole. Then, turn on the vacuum pump, flow N2 gas into the triangular container, and create a vacuum. Set the temperature to 120°C in the vacuum state and heat for 15 minutes from the point where it reaches 120°C. After heating for 15 minutes, flow N2 gas again and put the solution into a container (syringe).

[0121] After that, inject 13 mL of oleyl alcohol into a new three-necked flask and block all holes with a magnetic bar to create a vacuum inside the three-necked flask. Heat to 290°C while flowing N2 gas, and when it reaches 290°C, inject the solution in the syringe into the three-necked flask at 0.2 mL / min. After the injection, cool the three-necked flask. If alcohol is used at this time, cooling can be done quickly. When the temperature of the solution cools to approximately 90°C, the solution is placed in a centrifuge tube and centrifuged. At this time, hexane is also added to the centrifuge tube to make a total volume of 30 mL.

[0122] Centrifuge at 3600 RPM for 3 minutes. Discard the supernatant into an organic waste container, fill with hexane to 15 mL, and centrifuge once more under the same conditions. After completing the above process, place the supernatant in a reagent bottle, tape it, label it, and store it. This process is how the FITO core is manufactured.

[0123]

[0124] Process of forming a shell by coating with indium

[0125] In a three-necked flask, add 3 ml of the 4% FITO Sn solution manufactured with the above FITO core and 13 ml of oleyl alcohol, heat at 290℃ for 15 minutes by controlling the gas flow, and then flow N2 gas. After that, add 0.43792 g of indium acetate and 3 ml of oleic acid to the three-necked flask, heat for 15 minutes by controlling the gas flow in vacuum mode without turning on the vacuum pump, then flow N2 gas and withdraw the solution inside the three-necked flask with a syringe. Into the flowing N2 gas, inject 1 ml of the precursor solution maintained at 290℃ at a constant rate of 0.2 ml / min. After the injection, when the temperature of the solution has cooled to approximately 90℃, place the solution in a centrifuge tube, add the same amount of isopropyl as the above solution, and disperse it at 3600 RPM for 3 minutes. Afterwards, discard the supernatant as organic waste, add 15 ml of isopropyl alcohol and 15 ml of hexane, mix the nanoparticles that have settled in the tube, and redisperse them at 3600 RPM for 3 minutes. Finally, discard the supernatant, add 15 ml of hexane, mix the settled particles, and disperse them in a centrifuge at 2000 RPM for 2 minutes. Place the resulting solution in a reagent bottle, tape it, label it, and store it.

[0126] FITO obtained through this process has a core-shell structure. FIG. 11 is a TEM image of FITO containing 4% tin according to an embodiment of the present invention. As shown in FIG. 11, it can be seen that FITO is formed into an indium shell structure surrounding a central core FITO.

[0127] Meanwhile, FIG. 12 is a TEM photograph of a FITO core containing 1% tin, 4% tin, and 5% tin according to an embodiment of the present invention, FIG. 13 is a TEM photograph of FITO having a core-shell structure containing 1% tin, 4% tin, and 5% tin according to an embodiment of the present invention, and FIG. 14 is a graph showing the size distribution of cores and shells containing 1% tin, 4% tin, and 5% tin according to an embodiment of the present invention. In FIG. 14, the red graph represents the average value and histogram after measuring the size of 100 nanoparticle cores selected from the TEM photograph, and the blue graph represents the average value and histogram after measuring the size of 100 nanoparticle shells selected from the TEM photograph. In the case of 1% tin, it can be seen that a cube shape was synthesized.

[0128] The mass of dopant reagent according to the content (concentration) of the annotation is as shown in below.

[0129] < Dopant reagent mass by Sn(ac)4 concentration >Sn(ac)4Sn(ac)4 (mg)SnF4 (mg)In(ac)3 (mg)0%0.0048.681386.761%17.7448.681372.172%35.4948.681357.573%53.2348.681342.974%70.9848.681328.375%88.7248.681313.78

[0130] In one embodiment of the present invention, Sn(ac), SnF4, and In(ac) were prepared in a ratio of 0.35 to 2:1:25 to 30 as shown in Table 1. More specifically, as shown in Table 1, the experiment was conducted while maintaining the weight of SnF4 as is and increasing the weight of Sn(ac)4 by about 14.6 mg each time, while decreasing the weight of In(ac)3 by 17.75 mg each time.

[0131] Referring to FIGS. 12 to 14, it can be seen that the size of the FITO core particle is approximately 10 to 25 nm, and the size of the FITO shell particle is approximately 10 to 40 nm. In addition, FIG. 15 is a conceptual diagram of a uniform shell structure related to an embodiment of the present invention, and FIG. 16 is a conceptual diagram of a hierarchical shell structure related to an embodiment of the present invention. It can be seen that the shape changes from a uniform shell structure to a hierarchical shell structure as the tin content increases. The uniform shell structure is a shape in which the indium shell wraps the entire FITO core, and the hierarchical shell structure is a shape in which the indium shell partially wraps a part of the FITO core. In an embodiment of the present invention, it was confirmed that when 4% of tin was contained, a uniform shell structure was provided, and when 5% of tin was contained, a more hierarchical shell structure was provided. That is, when synthesizing FITO Core & shell, separate growth occurred rather than shell growth depending on the Sn(ac)4 ratio, and when 4% Sn(ac)4 was added, nanoparticles with a new geometric structure were created.

[0132] In addition, FIG. 17 is a Fourier transform infrared spectroscopy (FTIR) analysis graph of a core and shell containing 1% tin, 4% tin, and 5% tin in accordance with one embodiment of the present invention. Referring to FIG. 17, when the dopant concentration of the core increases, a large number of free electrons are generated, which increases the frequency and wavelength, but after the shell is formed, the wavelength decreases, and the graph shifts to the right compared to when there is only a core.

[0133] One embodiment of the present invention relates to a method for manufacturing FITO (F,Sn:In2O3, Fluorine Indium Tin Oxide) nanocrystal nanocubes in a single layer using a self-assembly method, and a FITO single-layer lamination method utilizing the same. The self-assembly is a process in which disorderly constituent materials spontaneously form patterns or high-dimensional structures through interactions between constituent elements without external intervention, and in one embodiment of the present invention, van der Waals interactions existing between monomers are utilized. Here, van der Waals forces refer to attractive or repulsive forces between molecules or between parts within a molecule, rather than covalent bonds or ionic electrical interactions. In addition, the term 'self-assembly' used in one embodiment of the present invention is a concept encompassing assembling on a support induced by non-covalent bonds, such as hydrogen bonds, ionic bonds, van der Waals bonds, hydrophobic bonds, and electrostatic bonds. Indium oxide (In2O3) and tin oxide (SnO2), which constitute ITO, form a certain structure through physical secondary bonding such as van der Waals attraction. Furthermore, in one embodiment of the present invention, indium oxide (In2O3) and tin oxide (SnO2) are formed through phase separation without contact with air or the substrate, thereby eliminating the possibility of side reactions and enabling more precise self-assembly.

[0134] FIG. 18 is a flowchart showing a FITO manufacturing process related to one embodiment of the present invention. Hereinafter, a FITO manufacturing method according to one embodiment of the present invention will be described with reference to FIG. 18.

[0135] First, a FITO manufacturing method according to one embodiment of the present invention comprises a step (S3110) of preparing a polar solution, and a step (S3120) of injecting FITO (F,Sn:In2O3, Fluorine Indium Tin Oxide) onto the polar solution and self-assembling through phase separation. That is, a container is prepared, a polar solution is poured into the container, and then FITO is injected onto the polar solution.

[0136] At this time, DMF (dimethylformamide) or water is used as the polar solution. That is, when the FITO is immersed in the polar solution, after a certain period of time in the self-assembly step (S3120), indium oxide (In2O3) and tin oxide (SnO2) are phase-separated and self-assembled on the polar solution. In this case, a single layer of FITO can be formed without contact with external air.

[0137] Meanwhile, in order to facilitate smoother self-assembly, in one embodiment of the present invention, the concentration of FITO may be adjusted by adding a polar solvent or organic solvent that enables phase separation. For example, hexane may be used as the organic solvent, and the lower part of the FITO is blocked from the outside by the polar solution, and when the hexane is diluted and mixed with the FITO, it serves to block the outside air at the top of the FITO. However, the present invention is not limited to hexane, and any polar solvent or organic solvent that enables phase separation without being mixed with the polar solution is sufficient.

[0138] FITO having a single particle layer structure can be manufactured by this process.

[0139] In addition, Fig. 19 is a flowchart showing a FITO deposition process related to one embodiment of the present invention, and Fig. 20 is a schematic diagram of a FITO deposition process related to one embodiment of the present invention. In one embodiment of the present invention, the FITO single layer manufacturing method may be utilized to deposit on a substrate, and the FITO deposition method will be described below with reference to Figs. 19 and 20.

[0140] The above FITO deposition method relates to a method for depositing a single layer of FITO on a substrate such as a silicon wafer. The FITO deposition method comprises the steps of preparing a substrate inside a container (S3210), immersing the substrate in a polar solution (S3220), injecting FITO (F,Sn:In2O3, Fluorine Indium Tin Oxide) onto the polar solution (S3230), and removing the polar solution using heat treatment (S3250). The FITO deposition method at this time uses DMF (dimethylformamide) or water as the polar solution, the same as in the FITO manufacturing method described above. In addition, in the step of injecting FITO, a polar solvent or an organic solvent that enables phase separation is added to the FITO (S3240) to adjust the concentration of FITO so that phase separation can occur better. Hexane was used as the organic solvent, and the lower part of the FITO is blocked from the outside by the polar solution, and when the hexane is diluted and mixed with the FITO, it acts to block the outside air at the top of the FITO. By mixing the hexane with the FITO, it is further isolated from the outside air. However, it is not limited to hexane, and any polar solvent or organic solvent that allows phase separation without mixing with the polar solution is sufficient.

[0141] Additionally, in the step of removing the polar solution, the substrate was heated at 100 to 200°C for 20 to 60 minutes to remove organic impurities. This heat treatment process was performed in an oven.

[0142] In this way, a single particle layer of FITO can be deposited on the substrate, for example, a silicon wafer.

[0143] Hereinafter, a method of depositing FITO on a substrate according to one embodiment of the present invention will be described in more detail with reference to FIGS. 19 and 20.

[0144] Self-assembly stage

[0145] 100 μl of FITO solution diluted to 1 mg / ml is weighed and poured into a Teflon container (310) having a diameter of 4 cm and a depth of 2 cm. A Teflon base (320) no higher than the container (310) is placed in the center of the Teflon container (320). A silicon wafer (330) measuring 1 cm x 1 cm is placed on the Teflon base (320). The DMF solution (340) is filled to a level slightly higher than the Teflon base (320). The top of the Teflon container is covered with a glass microscope slide (350) to reduce air turbulence. The desired amount of 1 mg / ml FITO solution (360) is injected and deposited on the surface of the DMF solution (340) through the space between the glass plates using a micropipette. To slow down the evaporation rate, the Teflon container (310) is covered and waited for 1 to 2 minutes until the nanocrystals self-assemble. After self-assembly, the DMF solution (340) is removed. Self-assembly takes approximately 20 seconds, but whether self-assembly has occurred can be confirmed using TEM. Self-assembly takes approximately 1 to 2 minutes.

[0146] Heat treatment (impurity removal) stage

[0147] The silicon wafer (330) on which the self-assembled FITO monolayer is deposited is left in the air at room temperature (approximately 25°C) for about a day. The wafer on which FITO is deposited is heated in an oven at 100 to 200°C for 30 minutes to remove excessive organic impurities.

[0148] FIG. 21 is a TEM photograph of FITO formed as a single layer related to one embodiment of the present invention. FIG. 21 is obtained through the above process, and a single layer of FITO can be laminated by self-assembling through phase separation on a polar solution such as DMF without reacting when indium oxide (In2O3) and tin oxide (SnO2) come into contact with the substrate (330) using a polar solution such as DMF.

[0149]

[0150] The above detailed description should not be construed as limiting in any respect and should be considered illustrative only. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present invention are intended to be included within the scope of the present invention.

[0151] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will readily appreciate that the present invention can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single entity may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

[0152] The scope of the present invention is indicated by the claims described below, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

[0153]

[0154] The mode for carrying out the invention has been described together with the best mode for carrying out the invention above.

[0155]

[0156] The present invention relates to hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystals on a dopant surface, and more particularly, to the technical field of synthesis and deposition of ITO (Indium Tin Oxide) and FITO (Fluorine-doped Indium Tin Oxide) nanocrystals. The present invention has industrial applicability by optimizing the infrared plasmonic properties and structural properties of the nanocrystals, thereby providing a nanomaterial that can be effectively utilized in various semiconductor and electromagnetic applications as well as in areas requiring high-performance optical filtering.

Claims

1. In hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystals on the dopant surface, A step of adding a first solution containing a mixture of indium acetate (In(ac)3) and a tin compound and oleic acid to a first reactor; A step of forming a vacuum state inside the first reactor after flowing nitrogen gas into the first reactor; A step of stirring the first solution at 120 to 150 ℃ and 500 to 700 rpm for 20 to 40 minutes; A step of extracting the stirred first solution and transferring it to a second reactor at a temperature of 230 to 320°C at a speed of 0.1 to 0.3 ml / min, and then mixing oleyl alcohol to form a second solution; and A step of cooling the second solution to room temperature; Including, but not limited to, The above first solution is, It is characterized by having a weight ratio of indium acetate (In(ac)3), tin compound, and oleic acid of 1300~1400:80~95:

10. The above first reactor and second reactor, Characterized by having a volume of 10ml to 10L A hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystal on a dopant surface, characterized by continuously supplying a mixture of indium acetate and tin compound to the first reactor.

2. In claim 1, The above tin compound is, It is characterized by being tin acetate (Sn(ac)4) or stannous chloride pentahydrate (SnCl4 · 5H2O). Hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystals characterized by a dopant surface comprising 1 to 15 wt% of indium and the remainder being indium acetate.

3. In claim 1, After the step of cooling the above second solution to room temperature, A step of mixing the cooled second solution and isopropyl alcohol (IPA) and then centrifuging; A step of redispersing the centrifuged material in hexane; and A hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystal on a dopant surface, characterized by further comprising a step of mixing the redispersed material with the isopropyl alcohol and then centrifuging it.

4. In claim 3, A hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystal on a dopant surface, characterized in that the above-mentioned redispersing step and re-centrifuging step are repeated two or more times.

5. In the hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystal of the dopant surface of any one of claims 1 to 4, The solution of the above nanocrystals is, It is characterized by having a volume of 10ml to 10L. The electron concentration of the above nanocrystal is, Hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystals characterized by a dopant surface having a size in the range of 1.00 X 1020 to 1.00 X 1025.

6. In hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystals on the dopant surface, A step for synthesizing FITO (F,Sn:In2O3, Fluorine Indium Tin Oxide) core particles having a tin (Sn) content of 2 to 10 wt%; and A step of coating indium on the above FITO core particles; Hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystals on the dopant surface containing .

7. In claim 6, The steps for manufacturing the above FITO core particles are: A step of preparing a first solution by mixing Sn(ac), SnF4, In(ac) and oleic acid; A step of preparing a second solution by mixing the first solution with oleyl alcohol heated to a temperature of 230 to 320°C; and A hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystal on a dopant surface, comprising a step of centrifuging the second solution to prepare a third solution.

8. In claim 7, The step of preparing the first solution is as follows: A step of measuring Sn(ac), SnF4, In(ac) and oleic acid in a ratio of 0.35~2:1:25~30 and placing them in a ternary solution; A step of forming a vacuum within the above-mentioned triple sphere by flowing nitrogen (N2) gas into the inside of the above-mentioned triple sphere; A step of heating the above-mentioned three-dimensional body in a vacuum at 100 to 150°C for 10 to 20 minutes; and A hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystal on a dopant surface, comprising: a step of flowing nitrogen (N2) gas through the above three spheres and containing the solution in a container; 9. In claim 7, The step of preparing the second solution is: Step of injecting oleyl alcohol into a three-necked flask and forming a vacuum state; A step of heating the three-necked flask to a temperature of 230 to 320°C while flowing nitrogen gas into the flask; A step of injecting the first solution into the three-necked flask at a constant ratio when the temperature of the above oleyl alcohol is 230 to 320°C; A step of cooling the above three-necked flask to 80 to 100°C; and A step of centrifuging the solution in the three-necked flask to obtain a second solution; Including, but not limited to, In the case of the above centrifugation, Hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystals characterized by the addition of hexane on the dopant surface.

10. In claim 7, The step of coating the above indium is: A step of preparing a fourth solution by mixing the third solution and Oleyl alcohol; A step of preparing a fifth solution by mixing indium acetate and oleic acid into the fourth solution; A step of heating the above fifth solution at 100 to 150°C for 10 to 20 minutes; A step of cooling the fifth solution in the three-necked flask to a temperature of 80 to 100°C; A step of preparing a sixth solution by mixing the cooled fifth solution with isopropyl; and Including a step of centrifuging the above sixth solution to obtain FITO having a core-shell structure, When centrifuging the above 6th solution, Hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystals on the dopant surface characterized by addition of isopropyl alcohol and hexane.

11. A method for producing a core-shell structured nanocrystal manufactured by any one of the methods of claims 1 to 10 and a product utilizing the same, The size of the above FITO core particles is 10 to 20 nm, and the size of the FITO shell particles is 20 to 40 nm. Hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystals on the dopant surface having a morphology that changes from uniform shelling to hierarchical shelling as the content of the above annotation increases.

12. In hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystals on the dopant surface, A step of preparing a polar solution of DMF (dimethylformamide) or water; and A step of injecting FITO (F,Sn:In2O3, Fluorine Indium Tin Oxide) onto the above polar solution and self-assembling through phase separation; Including, but not limited to, The above self-assembling step is, It is characterized by self-assembly as indium oxide (In2O3) and tin oxide (SnO2) phase-separate on a polar solution. Hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystals on a dopant surface characterized by controlling the concentration of a FITO solution by adding an organic solvent such as a polar solvent or hexane that enables phase separation.

13. In hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystals on the dopant surface, Step of preparing a substrate inside the container; A step of immersing the above substrate in a polar solution such as DMF (dimethylformamide) or water; A step of injecting FITO (F,Sn:In2O3, Fluorine Indium Tin Oxide) onto the above polar solution; and A step of removing the polar solution by using heat treatment; Hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystals featuring a dopant surface comprising:

14. In claim 13, The step of removing the above polar solution is: It is characterized by a step of heating the above substrate at 100 to 200°C for 20 to 60 minutes, The step of injecting the above FITO is: A hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystal on a dopant surface, characterized by comprising a step of controlling the FITO concentration by an organic solvent such as a polar solvent or hexane that enables phase separation.

15. In a hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystal on the surface of a dopant by any one of the methods of claims 1 to 14, A substrate on which FITO is deposited in a single layer; and A hierarchical cube-on-cube shaped plasmonic n-type semiconductor nanocrystal characterized by comprising a dopant surface that is fabricated as FITO.

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