KR20220151424A - Preparation method of quantum dots by ultrasonic irradiation - Google Patents

Abstract

The present invention relates to a method for manufacturing quantum dots using ultrasonic irradiation, and by manufacturing quantum dots through ultrasonic irradiation without controlling a high temperature reaction temperature, the manufacturing time can be reduced and quantum dots having a stable core-shell form can be manufactured. In addition, it is possible to adjust the size of the quantum dot core according to the intensity of ultrasound and the irradiation time, so it is possible to control the size thereof during the production of quantum dots, and by substituting an organic capping ligand of the quantum dot with a hydrophilic ligand, the quantum dot can be dispersed in a water-soluble solvent, thereby being able to be applied to bio industries such as cosmetics and diagnostic kits.

Description

Quantum dot manufacturing method using ultrasonic irradiation {Preparation method of quantum dots by ultrasonic irradiation}

The present invention relates to a method for manufacturing quantum dots using ultrasonic irradiation and quantum dots manufactured thereby.

Recently, interest in nanomaterials is rapidly increasing. Unlike particles in a bulk state, nanomaterials have unique electrical and physical properties. Among them, quantum dots having an ultrafine structure change significantly in electrical and optical properties depending on the quantum confinement effect. Nanomaterials can control the band gap, which is the distance between the valence band and the conduction band, according to the size of the quantum dots, and usually has a size of about 10 to 100 nm. Due to the particle control characteristics, the band gap decreases as the size of the quantum dots increases, resulting in a red color, which is long-wavelength light. In this way, depending on the particle size, light in the entire visible light range can be realized, both color purity and light stability are high, and unlike organic materials, light stability can be guaranteed as inorganic materials are used. It can be applied in various fields such as solar cells and biosensors.

In general, examples of methods for producing luminescent nanoparticles include a thermal decomposition method, a thermal decomposition method of a metal precursor at a high temperature, and an ultrasonic irradiation method. The thermal decomposition method is a method applied to the synthesis of the initial luminescent nanoparticles, and is still mainly used. The method for producing nanoparticles by thermal decomposition is a method of rapidly adding a metal precursor to a hot organic solvent (150 to 350 ° C) containing long-chain alkyl phosphine, alkyl phosphine oxide, and alkyl amine.

Non-Patent Document 1 (M. G. Bawendi, et al., Annu. Rev. Mater. Sci. 2000, 30, 545) discloses the synthesis of various luminescent nanoparticles by a thermal decomposition method, which requires a high temperature, During the reaction, water or oxygen must be blocked, and there are disadvantages in that a long reaction time is required.

Non-Patent Document 2 (MG Bawendi, et al., J. Am. Chem. Soc. 1993, 115, 8706, P. Guyot-Sionnest, et al., J. Phys. Chem. B 1998, 102, 3655) The synthesis of group II-VI luminescent nanoparticles is disclosed. Group II mainly uses metals (dimethyl cadmium, diethyl cadmium, diethyl zinc) having an alkyl group, and group VI mainly uses organic phosphine chalcogenides. (R ₃ PE, E = S, Se, Te). However, in this case, since only one luminescent nanoparticle can be synthesized in one reaction, it is not easy to synthesize a large amount of samples.

Non-Patent Document 3 (S. Kuwabata, J. Am. Chem. Soc. 2007, 129, 12388) relates to the synthesis by thermal decomposition of a metal precursor at high temperature, and a metal complex is added to an organic solvent to generate nanoluminescent nanoparticles by thermal decomposition. It is carried out in such a way as to synthesize particles. However, since the above method can only synthesize luminescent nanoparticles having one composition in one reaction, it is difficult to synthesize materials having various compositions.

On the other hand, Non-Patent Document 4 (A. Gedanken, et al., J. Sol. Stat. Chem. 2003, 172, 102) discloses a method using an ultrasonic irradiation method, and the method uses alcohol, water, amine-based, etc. For the solvent, metal acetate and metal chloride are used as metal raw materials, and sulfur, thioacetamide, and thiourea are used as sulfur raw materials. In this way, luminescent nanoparticles are synthesized by dissolving metal and sulfur raw materials in a solvent and then irradiating ultrasonic waves, which is simpler than the pyrolysis method and suitable for mass production.

However, since most of the synthesized core luminescent nanoparticles have low quantum efficiency, it is necessary to increase the quantum efficiency in order to apply them to various fields. At this time, a method of covering the surface of the nanoparticle with a stable organic or inorganic material is used. Non-Patent Document 5 (Dmitri V. Talapin, et al., Nano letters, 2001, 1, 207) discloses a method of treating the surface of CdSe quantum dots with allylamine or dodecylamine. It has the effect of increasing the luminous efficiency by 40-50%.

In addition, Patent Document 1 (U.S. Patent No. 6,322,901) and Patent Document 2 (U.S. Patent No. 6,207,229) disclose a material and manufacturing method using an inorganic material as a protective film for quantum dots, and the methods disclosed in the above patent documents disclose nanomaterials. When treating the particles, the luminous efficiency increases by about 30-50%.

However, the above methods have disadvantages in that the synthesis process of the core and the shell is complicated and a long reaction time is required. At the same time, luminous efficiency may decrease due to interstitial mismatch between core-shell structures, interface strain according to shell thickness, and the like. Accordingly, efforts have been made to solve the conventional problems and to synthesize luminescent nanoparticles of various compositions having high quantum efficiency and low toxicity.

As a conventional technology related to core-shell synthesis, Patent Document 3 (Korean Patent Registration No. 10-1238662) discloses a zinc oxide core-zinc sulfide shell structure nanopowder synthesis method. Specifically, adding thioacetamide to a solvent and ultrasonicating at 28 to 50 kHz for 10 minutes to 1 hour to form a thioacetamide solution in which the thioacetamide is dissolved in the solvent; Adding ZnO powder to the thioacetamide solution and uniformly dispersing it by ultrasonic treatment for 10 minutes to 1 hour; The thioacetamide solution in which the ZnO powder is dispersed is charged into an oven, and the temperature of the oven is maintained at 60 to 95° C. so that sulfur ions generated as thioacetamide is hydrolyzed react with zinc ions of the ZnO powder to obtain ZnO Forming a ZnS shell on the surface of the powder; Forming a ZnS shell on the surface of the ZnO powder to selectively separate the precipitate; and drying the precipitate to obtain a nanopowder having a ZnS shell formed on the surface of the ZnO powder. However, the core-shell synthesis method is a solution method using an oven, and has a disadvantage in that cost and time are consumed compared to the case of ultrasonic synthesis, which is not economical.

On the other hand, conventionally, cadmium-based quantum dots have been the main research field, but this not only causes serious problems in terms of environmental hazards and toxicity, but also has a problem of adversely affecting the human body when applied to the bio field. Accordingly, there is a trend to limit the use of cadmium, a toxic substance, worldwide, and research is being conducted to replace cadmium-based quantum dots. Therefore, there is a need for an easy manufacturing technology of quantum dots that are non-toxic and harmless to the environment and can be applied to the bio and medical fields.

In order to solve the above problems, an object of the present invention is to provide a method for manufacturing quantum dots using ultrasonic irradiation.

In addition, an object of the present invention is to provide a surface treatment method of quantum dots that can be dispersed in a water-soluble solvent through surface modification of the quantum dots.

In addition, another object of the present invention is to provide a quantum dot prepared according to the above manufacturing method.

In order to achieve the above object, the present invention 1) preparing a quantum dot core having an InP composition by mixing an indium (In) precursor, a phosphorus (P) precursor and a solvent and then irradiating ultrasonic waves; 2) adding a zinc (Zn) precursor, a selenium (Se) precursor, and a sulfur (S) precursor to the solution of step 1) and then irradiating ultrasonic waves to prepare a core-shell structured quantum dot having an InP/ZnSeS composition; and 3) washing and dispersing the quantum dots of step 2).

The indium precursor is a metal salt selected from the group consisting of indium-containing nitrates, carbonates, chlorides, phosphates, borates, oxides, sulfonates, sulfates, stearates, myristates, acetates and undecylenic salts. .

The phosphorus precursor is tris (trimethylsilyl) phosphine, triphenyl phosphate, trioctylphosphine, triphenylphosphine and triethyl phosphine. ) It is characterized in that selected from the group consisting of.

The solvent is characterized in that it is ether-based, hydrocarbon-based, alcohol-based or amine-based.

The zinc precursor is zinc acetate; zinc undecylenate; zinc stearate; zinc acetylacetonate; zinc nitrate; zinc acetate; And zinc chloride; any one or more selected from the group consisting of,

The selenium precursor is selenium; C ₆ ~ C ₈ aryl selenol; Straight or branched C ₁ ~ C ₂₀ alkyl selenol; Straight or branched C ₁ ~C ₂₀ alkenyl selenol; And straight-chain or branched C ₁ ~ C ₂₀ alkynyl selenol; any one or more selected from the group consisting of;

The sulfur precursor is sulfur; diethyldithiocarbamate; dimethyldithiocarbamate; C ₆ ~ C ₈ Arylthiol; straight-chain or branched-chain C ₁ ~C ₂₀ alkylthiol; Straight or branched C ₁ ~C ₂₀ alkenylthiol; and linear or branched C ₁ ~ C ₂₀ alkynylthiol; characterized in that any one or more selected from the group consisting of.

In the steps 1) and 2), the ultrasonic intensity is 2 to 200 kHz, and the ultrasonic irradiation time is 1 minute to 12 hours.

In step 3), the quantum dots are washed with an alcohol-based solution or a hydrocarbon-based solution and then dispersed in the hydrocarbon-based solution.

In addition, the present invention, after step 3), 4) obtaining quantum dots after centrifuging the solution of step 3); 5) redispersing the obtained quantum dots in an organic solvent; 6) replacing the quantum dot surface ligand by adding and stirring a hydrophilic ligand; 7) obtaining quantum dots after centrifuging the solution of step 6); and 8) washing the quantum dots obtained in step 7) and then dispersing them in distilled water to form an aqueous solution.

In addition, the present invention provides a quantum dot prepared by the above manufacturing method.

Unlike the conventional solution process synthesis method, the quantum dot manufacturing method according to the present invention does not require high-temperature reaction temperature control, and synthesizes quantum dots by irradiating uniform ultrasonic waves for a short time, thereby producing more economically stable core-shell quantum dots in a short time. can be manufactured

In addition, it is possible to manufacture quantum dots in a wide range from green to red by adjusting the size of the core and the temperature for forming the core of the quantum dots according to the intensity and irradiation time of the ultrasonic waves.

In addition, as organic capping ligands are replaced with hydrophilic capping ligands through surface treatment of quantum dots, they can be dispersed in aqueous solutions instead of organic solvents, and thus can be applied to bio industries such as cosmetics and diagnostic kits.

1 is a schematic diagram of water dispersion of quantum dots according to an embodiment of the present invention.
2 is an XRD measurement result of an InP core of a quantum dot according to an embodiment of the present invention.
3 is an XPS spectrum of (a) green quantum dots and (b) red quantum dots according to an embodiment of the present invention.
4 is a PL spectrum of (a) green quantum dots and (b) red quantum dots according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail. The embodiments and drawings introduced below are provided as examples to sufficiently convey the spirit of the present invention to those skilled in the art. Accordingly, the present invention may be embodied in other forms without being limited to the embodiments and drawings presented below. At this time, unless there is another definition in the technical terms and scientific terms used, they have meanings commonly understood by those of ordinary skill in the art to which this invention belongs, and the gist of the present invention in the following description and accompanying drawings Descriptions of well-known functions and configurations that may be unnecessarily obscure are omitted.

The present invention provides a method for manufacturing quantum dots using an ultrasonic irradiation method.

The present invention relates to a method for synthesizing quantum dots by irradiating uniform ultrasonic waves for a short time without adjusting the high-temperature reaction temperature reaching 200 ° C to 320 ° C, unlike the previously disclosed solution process quantum dot synthesis method, which shortens the synthesis time of quantum dots. And, it is possible to manufacture quantum dots in a stable core-shell form. In addition, since the formation temperature of the quantum dot core is determined according to the ultrasonic intensity, and the size of the core can be adjusted according to the ultrasonic irradiation time, it is possible to synthesize quantum dots in a wide range from green to red.

In addition, the present invention provides a surface treatment method for quantum dot particles. By substituting the organic capping ligand of the quantum dots with a hydrophilic capping ligand, the quantum dots can be dispersed in a hydrophilic solvent such as distilled water rather than an organic solvent, and thus can be widely applied to the bioindustry such as cosmetics and diagnostic kits.

A method for producing a quantum dot according to the present invention includes: 1) preparing a quantum dot core having an InP composition by mixing an indium (In) precursor, a phosphorus (P) precursor, and a solvent and then irradiating ultrasonic waves; 2) adding a zinc (Zn) precursor, a selenium (Se) precursor, and a sulfur (S) precursor to the solution of step 1) and then irradiating ultrasonic waves to prepare a core-shell structured quantum dot having an InP/ZnSeS composition; and 3) washing and dispersing the quantum dots of step 2).

The indium precursor may be a metal salt selected from the group consisting of nitrates, carbonates, chlorides, phosphates, borates, oxides, sulfonates, sulfates, stearates, myristates, acetates, and undecylenic salts containing indium as a metal ion. have. For example, it may be indium nitrate, indium chloride, or indium acetate, preferably indium acetate, but is not limited thereto. In the case of indium chloride, equipment may be corroded by chlorine generation. On the other hand, indium acetate has a lower raw material cost than indium nitrate, and indium acetate forms acetic acid due to the reaction of Acetate(oAc ^- ) + H ⁺ → acetic acid in the reaction solution and is slightly acidic, which makes it difficult to grow cores. It can affect the luminous intensity by cutting the surface of the core.

The phosphorus precursor is tris (trimethylsilyl) phosphine; (TMS) ₃ P), triphenyl phosphate, trioctylphosphine, triphenylphosphine (TPP) Or it may be selected from the group consisting of triethyl phosphite (TEP), preferably tris (trimethylsilyl) phosphine, but is not limited thereto. TPP has a PC bond that is difficult to break, making it difficult to form an InP core, whereas (TMS) 3P has the _best reactivity with indium and has a silyl group that is easy to fall off, so it prevents the growth of an InP core when irradiated with ultrasonic waves for a short time. It is judged to be the most favorable raw material to proceed.

Table 1 below shows ultrasonic irradiation conditions for InP core formation. As can be seen in Table 1 below, it can be seen that (TMS) ₃ P is synthesized in the shortest time.

ultrasonic output synthesis time Triphenylphosphine (TPP) more than 50% 30~60min Triethyl phosphite (TEP) more than 50% 30~60min Tris(trimethylsilyl)phosphine ((TMS) ₃ P) 30% or more ≤5min

The solvent may be ether-based, hydrocarbon-based, alcohol-based, or amine-based, but is not limited thereto, and a solvent capable of dissolving the metal salt may be appropriately selected and used.

The ether-based solvent may be, for example, octyl ether, butyl ether, hexyl ether, benzyl ether, phenyl ether or decyl ether, but is not limited thereto. The solutions are high-boiling solvents and have the advantage of increasing the reaction temperature in a short time and maintaining a high temperature during ultrasonic irradiation.

The hydrocarbon-based solvent may be hexane, toluene, xylene, chlorobenzoic acid, benzene, hexadecyne, tetradecyne, or octadecine, but is not limited thereto. The above solutions have the advantage of raising the reaction temperature high in a short time as a high boiling point solvent and maintaining a high temperature state.

The alcoholic solvent may be octyl alcohol, decanol, hexadecanol, ethylene glycol, 1,2-octanediol, 1,2-dodecanediol or 1,2-hexadecanediol, but is not limited thereto not. These solutions have the advantage of stabilizing the formed quantum dots because they have a hydroxyl group at the end of a long alkyl chain.

The amine-based solvent may be dodecylamine, hexadecylamine, octylamine, trioctylamine, dimethyloctylamine, or dimethyldodecylamine, but is not limited thereto. The above solutions have an amine group at the end of a long alkyl chain, and thus have the advantage of stabilizing the formed quantum dots.

The zinc precursor is zinc acetate; zinc undecylenate; zinc stearate; zinc acetylacetonate; zinc nitrate; zinc acetate; And zinc chloride; may be any one or more selected from the group consisting of, but is not limited thereto. In addition, in the present invention, in order to improve the reactivity (reaction rate) of zinc on the surface of the InP core particle, the zinc precursor may be dissolved in a solvent together with an organic acid and used in the form of a zinc precursor solution. The organic acid may be oleic acid, myristic acid or palmitic acid, but is not limited thereto. The organic acid acts as a role of dissolving the Zn complex into Zn ^{2+ and} as a capping ligand on the surface of InP/ZnSeS core-shell particles.

The selenium precursor is selenium; C ₆ ~ C ₈ aryl selenol; Straight or branched C ₁ ~ C ₂₀ alkyl selenol; Straight or branched C ₁ ~C ₂₀ alkenyl selenol; And linear or branched C ₁ ~ C ₂₀ alkynyl selenol; may be any one or more selected from the group consisting of, but is not limited thereto.

The sulfur precursor is sulfur; diethyldithiocarbamate; dimethyldithiocarbamate; C ₆ ~ C ₈ Arylthiol; straight-chain or branched-chain C ₁ ~C ₂₀ alkylthiol; Straight or branched C ₁ ~C ₂₀ alkenylthiol; And linear or branched C ₁ ~ C ₂₀ alkynylthiol; may be any one or more selected from the group consisting of, but is not limited thereto.

In the present invention, quantum dots are manufactured through ultrasonic irradiation. When ultrasonic waves are irradiated, energy is transferred in the process of generating and destroying microcavities inside the solution due to ultrasonic waves, and thus has a catalytic effect on the reaction.

In the present invention, the intensity of ultrasound may be 2 to 200 kHz. Preferably, the ultrasonic irradiation intensity in step 1) may be 20 kHz. When the intensity is less than 20 kHz, the quantum dot core does not grow, and when the intensity exceeds 20 kHz, the quantum dot core does not grow and is decomposed by super-intense ultrasound, making it impossible to synthesize the quantum dot.

Also, preferably, the ultrasonic irradiation intensity in step 2) may be 12 kHz. When the intensity is less than 12 kHz, it is a reaction temperature at which the zinc shell formation reaction does not occur on the surface of the quantum dot core, and when the intensity exceeds 12 kHz, the zinc shell is not formed on the surface of the quantum dot core and the core may be decomposed.

In addition, the ultrasonic irradiation time in the present invention may be 1 minute to 12 hours. Preferably, the ultrasonic irradiation time of step 1) may be 10 to 20 minutes, and core synthesis of quantum dots having emission wavelengths of 520 nm to 650 nm is possible with a reaction time within the above range. If the reaction time is shorter than the reaction time, the core does not grow, and if the reaction time exceeds the reaction time, the quantum dot core growth progresses too much, making it impossible to synthesize the red quantum dots and reducing the luminous efficiency.

Also, preferably, the ultrasonic irradiation time in step 2) may be 30 minutes. When reacting for less than 30 minutes, a shell is formed, but the thickness of the shell is thin, which lowers the luminous efficiency, and the shell is not formed with a stable lattice structure on the surface of the core.

In step 3), the quantum dots of step 2) are washed and dispersed.

The washing in step 3) is performed to remove and separate the quantum dots from the metal precursor solution.

The washing may be performed with an alcohol-based solution and/or a hydrocarbon-based solution, and it is preferable to perform the washing 2 to 10 times in terms of improving the purity of the quantum dots, but is not limited thereto.

Examples of the alcohol-based solvent include ethanol, methanol, and octyl alcohol, and the solutions are polar solvents, which induce precipitation of quantum dots dispersed in a non-polar solvent to facilitate separation of the produced quantum dots. .

Examples of the hydrocarbon-based solvent include hexane, toluene, chloroform, and the like, and the solutions are non-polar solvents and have the advantage of uniformly dispersing quantum dots stabilized by an alkyl chain.

Next, after the washed quantum dots are precipitated, the supernatant is removed to separate the quantum dots. The method for removing the supernatant is preferably centrifugal separation, but is not limited thereto. When centrifugal separation is used, undissolved quantum dots mixed with the solvent in the reactor can be separated using centrifugal force and difference in specific gravity.

The dispersion in step 3) is performed to obtain the separated quantum dots by dispersing them in a solvent. The dispersion may secure stability of the quantum dots by dispersing in a hydrocarbon-based solution such as hexane, toluene, or chloroform.

In addition, the present invention may further include a surface treatment step of the quantum dots in which organic capping ligands on the surface of the quantum dots are replaced with hydrophilic capping ligands.

In general, uniform size semiconductor nanoparticles with high stability have a disadvantage that they cannot be used in aqueous solutions because their surfaces are hydrophobic. However, in order to apply nanoparticles to biomaterials or biofields, the surface of the particles must be treated with a hydrophilic property to overcome these disadvantages.

In more detail, after step 3), 4) obtaining quantum dots after centrifuging the solution in step 3); 5) redispersing the obtained quantum dots in an organic solvent; 6) replacing the quantum dot surface ligand by adding and stirring a hydrophilic ligand; 7) obtaining quantum dots after centrifuging the solution of step 6); and 8) washing the quantum dots obtained in step 7) and then dispersing them in distilled water to form an aqueous solution.

The hydrophilic ligand may be an organic ligand including a hydroxy group, a carboxyl group, an amino group, a mercapto group, etc., preferably a mercapto acid containing a mercapto group and a carboxyl group, more preferably a C ₂ ~ C ₈ mercaptosanyl. can For example, it may be any one selected from the group consisting of 3-mercaptopropionic acid (MPA), mercaptoacetic acid (MAA), or mercaptosuccinic acid (MSA), but is not limited thereto. The hydrophilic ligand may be chemically or physically bonded to the surface of the shell.

In another aspect, the present invention provides a quantum dot prepared by the above manufacturing method.

Hereinafter, the present invention will be described in more detail through examples. However, the following examples are only one reference for explaining the present invention in detail, but the present invention is not limited thereto, and may be implemented in various forms. Also, unless defined otherwise, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description herein is merely to effectively describe specific embodiments and is not intended to limit the present invention.

Example 1. Green quantum dot synthesis using ultrasonic irradiation

0.0876 g of Indium acetate (In(oAc) ₃ ) and 0.2055 g of Myristic acid (MA) are dissolved in 5 ml of 1-Octadecene (ODE). Add 88 μl of Tris(trimethylsilily)phosphine ((TMS) ₃ P) and irradiate for 10 minutes at an ultrasonic intensity of 20 kHz. After adding 0.03 ml each of Selenium (TOPSe) and Sulfur (TOPS) dissolved in 5 ml of Zinc precursor solution and Trioctylphosphine (TOP), ultrasonic waves were irradiated at 12 kHz for 30 minutes. To improve the stability of the particles, transfer to a 3-necked flask and maintain at 320 ° C for 20 minutes to complete the reaction.

Example 2. Red quantum dot synthesis using ultrasonic irradiation

In the same manner as in Example 1, Indium acetate (In(oAc) ₃ ) and Myristic acid (MA) were dissolved in 1-Octadecene (ODE), and then Zn (Zinc) precursor and (TMS) ₃ P were added. Irradiated at an ultrasonic intensity of 20 kHz for 20 minutes to grow an InP core larger than that of Example 1. After adding 0.03 ml each of Selenium (TOPSe) and Sulfur (TOPS) dissolved in 5 ml of Zinc precursor solution and Trioctylphosphine (TOP), ultrasonic waves were irradiated at 12 kHz for 30 minutes. To improve the stability of the particles, transfer to a 3-necked flask and maintain at 320 ° C for 20 minutes to complete the reaction.

Example 3. Surface modification of quantum dots using ultrasonic irradiation

1 shows a schematic diagram for surface modification of the quantum dots synthesized in Examples 1 and 2 to be hydrophilic for water dispersion. First, the quantum dot solutions of Examples 1 and 2 and acetone were mixed in a ratio of 1:3, centrifuged, and the supernatant was discarded. The obtained quantum dots are redispersed in chloroform. 200 μl of 3-mercaptopropionic acid (3-MPA) was added to 10 ml of methanol, and the pH was titrated to 13 using 1M KOH to prepare a 3-MPA solution. The prepared 3-MPA solution was added to the chloroform solution in which the quantum dots were dispersed and stirred for 1 hour. The quantum dots are centrifuged, the supernatant containing chloroform and 3-MPA is discarded, and the obtained quantum dots are washed twice or more with methanol or ethanol and then dispersed in distilled water.

Experimental Example 1. XRD measurement of InP core

In order to analyze the crystal phase of the InP core particles synthesized according to the present invention, X-ray diffraction analysis of only the InP core particles prepared by the ultrasonic irradiation method of the present invention was performed. It was analyzed by Rigaku's D/MAX2200V/PC, and the results are shown in FIG. 2.

As shown in FIG. 2, when confirming the XRD peak of the InP core particle, it can be confirmed that it has a peak of the InP crystal phase (JCPDF#01-070-2902). Through this, it was confirmed that the InP core was synthesized by the ultrasonic irradiation method of the present invention.

Experimental Example 2. ICP-AES measurement of InP/ZnSeS core-shell particles

In order to analyze the inorganic element content of the InP/ZnSeS core-shell particles synthesized according to the present invention, the InP/ZnSeS core-shell particles prepared in Examples 1 and 2 were subjected to ICP-AES analysis. Analysis was performed using Thermo Scientific's iCAP 7400 duo, and the results are shown in Table 2 below.

Zn (mg/kg) P (mg/kg) In (mg/kg) Example 1 649 988 1920 Example 2 938 610 7280

As shown in Table 2, it can be confirmed that InP/ZnSeS quantum dots having In, Zn, and P were synthesized in Examples 1 and 2. In the case of Example 2, it is determined that the amount of In was measured more because the core size increased because the core formation time through ultrasonic irradiation was longer than that of Example 1. Through this, it can be expected that the size of the core can be adjusted according to the ultrasonic irradiation time.

Experimental Example 3. XPS measurement of InP/ZnSeS core-shell particles

For elemental analysis of the InP/ZnSeS core-shell particles synthesized according to the present invention, X-ray photoelectron spectroscopy was performed on the InP/ZnSeS core-shell particles prepared in Examples 1 and 2 above. The analysis was performed with KRATOS' AXIS NOVA, and the results are shown in FIG. 3 .

3A is an XPS spectrum of InP/ZnSeS core-shell particles synthesized in Example 1, and FIG. 3B is an XPS spectrum of InP/ZnSeS core-shell particles synthesized in Example 2. By checking each XPS peak, it can be confirmed that the particles are particles having elements of In, Zn, P, and Se. On the other hand, S overlaps with the P peak and is difficult to observe. Through this, it was confirmed that the particles in which the ZnSeS shell was formed on the surface of the InP core in Example 1 and Example 2 were stably synthesized.

Experimental Example 4. PL spectrum of InP/ZnSeS core-shell particles

In order to analyze the photoluminescence of the InP/ZnSeS core-shell particles synthesized according to the present invention, the PL spectrum of the InP/ZnSeS core-shell particles prepared in Examples 1 and 2 was measured. Analysis was performed using PerkinElmer's LS50B Luminescence Spectrometer, and the results are shown in FIG. 4 .

As shown in FIG. 4a, it was confirmed that the quantum dots synthesized in Example 1 emit PL with the highest wavelength of 540 nm (FWHM=38). In addition, as shown in FIG. 4b, it was confirmed that the quantum dots synthesized in Example 2 emitted PL with the highest wavelength of 638 nm (FWHM = 45). Through this, it can be confirmed that the size of the core of the quantum dots prepared by ultrasonic irradiation according to the present invention can be adjusted according to the ultrasonic irradiation time, and PL emission is possible from green to red, that is, within a range of 520 nm to 650 nm.

The above description is merely illustrative of the present invention, and those skilled in the art will be able to make various modifications without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in this specification are intended to explain, not limit, the present invention, and the spirit and scope of the present invention are not limited by these embodiments. The protection scope of the present invention should be construed according to the following claims, and all technologies within the equivalent range should be construed as being included in the scope of the present invention.

Claims (12)

1) preparing a quantum dot core having an InP composition by mixing an indium (In) precursor, a phosphorus (P) precursor, and a solvent and then irradiating ultrasonic waves;
2) adding a zinc (Zn) precursor, a selenium (Se) precursor, and a sulfur (S) precursor to the solution of step 1) and then irradiating ultrasonic waves to prepare a core-shell structured quantum dot having an InP/ZnSeS composition; and
3) washing and dispersing the quantum dots of step 2); quantum dot manufacturing method using ultrasonic irradiation including
The method of claim 1, wherein the indium precursor is selected from the group consisting of indium-containing nitrates, carbonates, chlorides, phosphates, borates, oxides, sulfonates, sulfates, stearates, myristates, acetates, and undecylenic salts. Manufacturing method characterized in that the metal salt
The method of claim 1, wherein the phosphorus precursor is tris (trimethylsilyl) phosphine (Tris (trimethylsilyl) phosphine), triphenyl phosphate (Triphenyl phosphate), trioctylphosphine (Trioctylphosphine), triphenylphosphine (Triphenylphosphine) and tri Manufacturing method characterized by being selected from the group consisting of ethyl phosphine (Triethyl phosphite)
The method of claim 1, wherein the solvent is ether-based, hydrocarbon-based, alcohol-based or amine-based.
The method of claim 1, wherein the zinc precursor is zinc acetate; zinc undecylenate; zinc stearate; zinc acetylacetonate; zinc nitrate; zinc acetate; And zinc chloride; manufacturing method characterized in that any one or more selected from the group consisting of
According to claim 1, wherein the selenium precursor is selenium; C ₆ ~ C ₈ aryl selenol; Straight or branched C ₁ ~ C ₂₀ alkyl selenol; Straight or branched C ₁ ~C ₂₀ alkenyl selenol; And linear or branched chain C ₁ ~ C ₂₀ alkynyl selenol; manufacturing method characterized in that any one or more selected from the group consisting of
The method of claim 1, wherein the sulfur precursor is sulfur; diethyldithiocarbamate; dimethyldithiocarbamate; C ₆ ~ C ₈ Arylthiol; straight-chain or branched-chain C ₁ ~C ₂₀ alkylthiol; Straight or branched C ₁ ~C ₂₀ alkenylthiol; And linear or branched chain C ₁ ~ C ₂₀ alkynylthiol; manufacturing method characterized in that any one or more selected from the group consisting of
The method of claim 1, wherein in steps 1) and 2), the ultrasonic intensity is 2 to 200 kHz.
The method according to claim 1, wherein in steps 1) and 2), the ultrasonic irradiation time is 1 minute to 12 hours.
The method of claim 1, wherein in step 3), the quantum dots are washed with an alcohol-based solution or a hydrocarbon-based solution and then dispersed in the hydrocarbon-based solution.
The method of claim 1, wherein the quantum dots have a light emission wavelength of 520 nm to 650 nm.
The method of claim 1, after step 3),
4) obtaining quantum dots after centrifuging the solution of step 3);
5) redispersing the obtained quantum dots in an organic solvent;
6) replacing the quantum dot surface ligand by adding and stirring a hydrophilic ligand;
7) obtaining quantum dots after centrifuging the solution of step 6); and
8) washing the quantum dots obtained in step 7) and then dispersing them in distilled water to form an aqueous solution; manufacturing method characterized in that it further comprises

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