WO2021054650A2 - Method for manufacturing quantum dots and quantum dots manufactured thereby - Google Patents

Method for manufacturing quantum dots and quantum dots manufactured thereby Download PDF

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WO2021054650A2
WO2021054650A2 PCT/KR2020/011741 KR2020011741W WO2021054650A2 WO 2021054650 A2 WO2021054650 A2 WO 2021054650A2 KR 2020011741 W KR2020011741 W KR 2020011741W WO 2021054650 A2 WO2021054650 A2 WO 2021054650A2
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solution
precursor
organic solvent
znsete core
halide
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French (fr)
Korean (ko)
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WO2021054650A3 (en
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강현진
길경훈
박지솔
김경남
하성민
남춘래
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주식회사 한솔케미칼
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/88—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing selenium, tellurium or unspecified chalcogen elements
    • C09K11/881—Chalcogenides
    • C09K11/883—Chalcogenides with zinc or cadmium
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/56—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing sulfur
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/56—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing sulfur
    • C09K11/562—Chalcogenides
    • C09K11/565—Chalcogenides with zinc cadmium
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/88—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing selenium, tellurium or unspecified chalcogen elements

Definitions

  • the present invention relates to a method of manufacturing a quantum dot and a quantum dot manufactured thereby.
  • Quantum dot is a material having a crystal structure of several nano to tens of nanometers, and it is easy to adjust the band gap by controlling the size and composition of nanoparticles, and can realize light of various wavelengths. It can have electrical, magnetic, optical, chemical, and mechanical properties. These quantum dots can be applied to various devices such as light-emitting diodes (LEDs), organic-inorganic hybrid electroluminescent devices, inorganic electroluminescent devices, solar cells, and transistors.
  • LEDs light-emitting diodes
  • organic-inorganic hybrid electroluminescent devices organic-inorganic hybrid electroluminescent devices
  • inorganic electroluminescent devices solar cells, and transistors.
  • an LED display to which a quantum dot is applied such as a quantum dot TV, uses a blue-emitting LED as a light source, and the quantum dot absorbs light having a predetermined wavelength and emits light having a different wavelength-a quantum dot-polymer composite sheet (QD It is included in the form of a sheet).
  • QD quantum dot-polymer composite sheet
  • OLED displays to which quantum dots are applied like OLED TVs, are in the spotlight as next-generation light emitting displays because, unlike conventional OLEDs, they have excellent color reproduction and color purity.
  • An object of the present invention is to provide a method for manufacturing quantum dots having a light emission wavelength of 445 nm or more and having high quantum efficiency by uniformly controlling the particle diameter of a ZnSeTe core in synthesizing quantum dots.
  • another object of the present invention is to provide a quantum dot having a light emission wavelength of 445 nm or more and high quantum efficiency.
  • the present invention includes heating a first solution including a first zinc precursor, a first carboxylic acid compound, and a first organic solvent; Forming a second solution by injecting a first mixture of a first selenium (Se) precursor and a telenium (Te) precursor into a second organic solvent; Mixing the heated first solution and the second solution to form a ZnSeTe core; And forming a shell of at least one layer on the ZnSeTe core, wherein the second organic solvent has a difference in polarity index with the first organic solvent in the range of 0 to 0.4.
  • the present invention provides a quantum dot having an emission wavelength of 445 nm or more, including a ZnSeTe core, and at least one layer of a shell, manufactured by the above-described method.
  • quantum dots having a light emission wavelength of 445 nm or more and high quantum efficiency can be manufactured.
  • Example 1 is a graph showing emission spectra of quantum dots prepared in Example 1 and Comparative Example 2, respectively.
  • an organic solvent having the same or similar polarity as the organic solvent used in the zinc precursor-containing solution is added to the zinc precursor-containing solution together with the selenium precursor and the telenium precursor and reacted to form a ZnSeTe core.
  • a quantum dot having a light emission wavelength of 445 nm or more and having high quantum efficiency can be manufactured.
  • a method of manufacturing a quantum dot includes heating a first solution including a first zinc precursor, a first carboxylic acid compound, and a first organic solvent; Forming a second solution by injecting a first mixture of a first selenium (Se) precursor and a telenium (Te) precursor into a second organic solvent; Mixing the heated first solution and the second solution to form a ZnSeTe core; And forming a shell of at least one layer on the ZnSeTe core, wherein the second organic solvent has a difference in polarity index with the first organic solvent in the range of 0 to 0.4.
  • step S100' After preparing a first solution including a first zinc (Zn) precursor, a first carboxylic acid compound, and a first organic solvent, the first solution is heated (hereinafter referred to as'step S100').
  • the step S100 includes (S110) preparing a first solution by introducing a first zinc precursor and a first carboxylic acid-based compound into a first organic solvent; And (S120) heating the first solution under vacuum and then raising the temperature to a higher temperature under a nitrogen gas atmosphere, but is not limited thereto.
  • the first zinc precursor usable in the present invention is not particularly limited as long as it is a zinc metal itself or a compound containing zinc (Zn), as long as it is commonly known in the art.
  • Zn zinc
  • the zinc precursor may be zinc acetate.
  • the first carboxylic acid-based compound usable in the present invention is a material capable of uniformly dispersing the first zinc precursor in the first organic solvent, such as oleic acid, myristoleic acid, palmitolein C 6 ⁇ C 30 unsaturated fatty acids such as Palmitoleic acid, Linoleic acid, Eicosapentaenoic acid (EPA), Docosapentaenoic acid (DPA), and the like; Lauric acid, palmitic acid, stearic acid, myristic acid, elaidic acid, eicosanoic acid, Heneicos Heneicosanoic acid, tricosanoic acid, docosanoic acid, tetracosanoic acid, hexacosanoic acid, heptacosanoic acid, octacosanoic acid There are saturated fatty acids of C 3 to C 30 such as (octacosanoic acid) and
  • the first organic solvent usable in the present invention may be used without limitation, as long as it is an organic solvent used in the synthesis of ZnSeTe core in the art, for example, C 6 ⁇ C 22 primary alkylamines such as hexadecylamine, dioctylamine Amine-based organic solvents such as C 6 to C 22 secondary alkylamines and C 6 to C 40 tertiary alkylamines such as trioctylamine; Nitrogen (N)-containing heterocyclic compounds such as pyridine; Pentene, hexine, heptene, octadecene, nonene, decene, undecene, dodecene, tridecene, tetra Aliphatic hydrocarbons of C 5 to C 40 such as tetradecene, pentadecene, octane, hexadecane, octadecane, octadecen
  • the content of the first zinc precursor, the first carboxylic acid compound, and the first organic solvent is not particularly limited.
  • the content of the first carboxylic acid-based compound may be about 1 to 5 mol per 1 mol of the first zinc precursor.
  • the content of the first organic solvent may be about 100 to 50,000 ml per 1 mol of the first zinc precursor.
  • This first solution may be heated under vacuum and then heated to a higher temperature under a nitrogen atmosphere.
  • the heating temperature and time under vacuum are not particularly limited, and may be heated at, for example, about 100° C. or higher, specifically about 100 to 160° C. for about 0.5 to 24 hours.
  • heating temperature and time are not particularly limited, and for example, the temperature may be raised to about 200° C. or more, specifically about 250 to 350° C.
  • This step is a step of forming a second solution containing a selenium precursor and a telenium precursor by injecting a first mixture of a first selenium (Se) precursor and a telenium precursor into a second organic solvent (hereinafter referred to as'step S200'). Is).
  • the second organic solvent a solvent having the same or similar polarity index as the first organic solvent used in step S100, specifically the same or similar polarity, and the same or similar boiling point (Boiling Point, BP), more specifically the same solvent is used.
  • the polarity index of the solvent generally indicates the polarity of the solvent, and when the polarity of water is 1.000, it means a relative polarity.
  • the second organic solvent is a solvent having a difference in polarity with the first organic solvent of about 0 to 0.4.
  • the second organic solvent may be a solvent having a difference in polarity with the first organic solvent of about 0 to 0.4 and a difference in boiling point with the first organic solvent of about 0 to 100°C.
  • the second organic solvent may be the same solvent as the first organic solvent.
  • This second organic solvent prevents aggregation of the first selenium precursors and telenium precursors when storing and injecting the second solution, while mixing the second solution with the first solution to react the second solution and the first solution.
  • it also induces a uniform reaction by preventing a difference in boiling point (BP) between the second solution and the first solution. Therefore, in the present invention, a ZnSeTe core having a uniform particle diameter can be synthesized.
  • This step S200 has no temporal precedence relationship with the step S100. For example, it may be performed after step S100, but may be performed before step S100 or may be performed separately at the same time as step S100.
  • the first mixture in this step includes a first selenium precursor and a telenium precursor.
  • the first selenium precursor is not particularly limited as long as it is known in the art as a compound containing selenium (Se), and for example, selenium-diphenylphosphine selenide, selenium-trioctylphosphine, selenium-tri It may be butylphosphine, selenium-triphenylphosphine, diethyl diselenide, dimethyl selenide, bis(trimethylsilyl)selenide [bis(trimethylsilyl)selenide], and the like. These may be used alone or in combination of two or more.
  • the telenium precursor is not particularly limited as long as it is known as a compound containing telenium (Te) in the art, for example, tellurium-trioctylphosphine, tellurium-tributylphosphine, or tellurium-triphenylphosphine. There are, and these may be used alone or in combination of two or more.
  • Te telenium
  • the content of the first mixture in which the first selenium precursor and the telenium precursor are mixed is not particularly limited, for example, the total content of selenium and telenium in the first mixture is about 0.05 to 2 with respect to 1 mol of zinc in the first zinc precursor. mol range.
  • the mixing ratio of the first selenium precursor and the telenium precursor is not particularly limited, and may be, for example, a molar ratio of 1: 0.0001 to 0.029, specifically a molar ratio of 1: 0.001 to 0.01. If the content ratio of the telenium precursor to the content of the first selenium precursor exceeds 0.029 molar ratio, the tail in the long wavelength region of the emission wavelength may increase, and thus the color purity of blue may decrease.
  • the second organic solvent used in this step is the same as those described for the first organic solvent, and thus are omitted.
  • the second organic solvent of the present invention is a solvent having a difference in polarity with the first organic solvent used in step S100 in the range of 0 to 0.4, and specifically, the difference in polarity with the first organic solvent. It is a solvent in the range of 0 to 0.4 and a boiling point difference of 0 to 100°C with the first organic solvent, and more specifically, the same solvent as the first organic solvent.
  • the second organic solvent when the first organic solvent is an amine-based organic solvent, specifically a tertiary alkylamine, in consideration of the difference in polarity with the first organic solvent and further, the difference in boiling point with the first organic solvent, the second organic solvent It may also be an amine-based organic solvent, specifically a tertiary alkylamine. According to an example, both the first organic solvent and the second organic solvent may be a tertiary amine containing a C 6 ⁇ C 40 alkyl group, specifically trioctylamine.
  • the content of the second organic solvent is adjusted according to the content of the first mixture, and may be, for example, about 1 to 100 parts by volume based on 100 parts by volume of the first mixture.
  • This step is a step of mixing and reacting the first solution heated in step (S100) with the second solution formed in step (S200) to form a ZnSeTe core (hereinafter referred to as'step S300').
  • the second solution is added to the heated first solution, or the heated first solution is added to the second solution to mix the heated first solution and the second solution.
  • the use ratio (mixing ratio) of the first solution and the second solution is not particularly limited, and may be 1: 0.001 to 1 volume ratio.
  • the temperature, speed, and time are not particularly limited, and vary depending on the amount of the second solution.
  • the second solution may be added to the first solution for about 6 hours or less at room temperature or higher, specifically, about 15 to 30°C. At this time, the injection rate can be adjusted according to the content of the second solution.
  • a halide solution may be additionally added.
  • the halide solution is a solution in which halide is dispersed or dissolved in a solvent, and by etching and coating the surface of the ZnSeTe core with the halide in the halide solution, the growth and surface of the ZnSeTe core are stabilized, leading to high quantum efficiency of the ZnSeTe core.
  • the organic material layer e.g., organic ligand layer
  • a material constituting the halide such as a metal cation-halide anion or a hydrocarbon group-halogen
  • a material constituting the halide such as a metal cation-halide anion or a hydrocarbon group-halogen
  • the occurrence of defects on the surface of the ZnSeTe core due to the removal of the organic ligand layer is suppressed by the coating layer formed of halide, the growth of the ZnSeTe core and stability of the surface are improved, thereby obtaining quantum dots having high quantum efficiency.
  • the manufactured quantum dot has a halide layer interposed in some or all of the interface between the ZnSeTe core and the shell.
  • the halide usable in the present invention is not particularly limited as long as it is a halide known in the art, and not only inorganic halide such as fluoride, chloride, bromide, iodide, etc., but also halogenated hydrocarbons (eg, C 1 ⁇ C 12 alkyl halide) It may be an organic halide such as. Specific examples include, but are not limited to, NH 4 Cl, NH 4 Br, NH 4 I, ZnCl 2 , ZnBr 2 , ZnI 2 , CH 3 Cl, CH 3 Br, CH 3 I, and the like.
  • the solvent in the halide solution is not particularly limited as long as it is a polar solvent or non-polar solvent known in the art capable of dissolving or dispersing the halide.
  • the content of the halide solution is not particularly limited, and may be, for example, in the range of about 0.01 to 100 parts by volume based on 100 parts by volume of the second solution.
  • the concentration of the halide solution is not particularly limited, and may be, for example, about 1 to 30% by weight, specifically about 5 to 20% by weight, and more specifically about 8 to 15% by weight based on the total amount of the halide solution. .
  • the concentration of the halide solution may be about 10% by weight.
  • the ZnSeTe core particles formed in the above-described step (S300) are dissolved together with impurities in a solvent.
  • the ZnSeTe core particles may be separated.
  • a halide may be added together with an anti-solvent. This purification process may be repeatedly performed one or more times.
  • Non-limiting examples of the anti-solvent include acetone, ethanol, methanol, butanol, propanol, isopropyl alcohol, tetrahydrofuran, dimethyl sulfoxide, dimethylformamide, and the like, and these may be used alone or in combination of two or more. have.
  • the method of separating the ZnSeTe core particles is not particularly limited as long as it is known as a liquid-solid separation method in the art, and includes, for example, a centrifugal separation method.
  • the halide not only prevents defects on the surface of the ZnSeTe core from occurring when the ZnSeTe core particles are separated and purified, but also improves the reaction between the ZnSeTe core and the shell precursor so that a shell is formed and grown on the ZnSeTe core. have.
  • halogen F, Cl, Br, I, etc.
  • metal fluoride metal chloride, metal bromide, metal iodide, etc. It may be the same metal halide salt.
  • ZnCl 2 , ZnBr 2 , ZnI 2 NH 4 Cl, NH 4 Br, NH 4 I, and the like.
  • the organic halide may be a halogenated hydrocarbon or the like, specifically, a C 1 ⁇ C 12 alkyl halide, and the like, such as CH 3 Cl, CH 3 Br, CH 3 I, and the like. These may be used alone or in combination of two or more.
  • the halide may be ZnCl 2.
  • the content of halide is not particularly limited, for example, the ratio of the volume (V 2 ) of the solution in which the halide is dissolved (hereinafter,'halide solution') to the volume (V 1 ) of the ZnSeTe core dispersion (V 2 /V 1 ) may be about 0.1 to 5, and the halide content in the halide solution is about 0.1 wt% or more, and the halide can be dissolved up to the solubility limit.
  • the ZnSeTe core particles separated above may be redispersed in a non-polar solvent.
  • the ZnSeTe core particles are colloidally dispersed and present in a non-polar solvent, they can be stably stored.
  • non-polar solvents examples include hexane, benzene, xylene, toluene, octane, chloroform, chlorobenzene, tetrahydrofuran (THF), methylene chloride, 1,4 -Dioxane (1,4-dioxane), diethyl ether (diethyl ether), cyclohexane, dichlorobenzene, and the like, but are not limited thereto.
  • This step is a step of forming and growing a shell of at least one layer on the ZnSeTe core formed in step (S300) (hereinafter referred to as'step S400'), in which a shell is formed and grown on the core of quantum dots in the industry. If it is a method, it is not particularly limited. In this case, the shell formation process may be appropriately selected according to the component, thickness, and number of layers of each shell.
  • step S400 may include forming a third solution by mixing the ZnSeTe core formed in step S410 with a solution containing a second zinc precursor; (S420) adding a second selenium precursor to the third solution and reacting to form a solution containing first particles having a ZnSeTe core/ZnSe shell structure; And (S430) adding a sulfur precursor to the solution containing the first particles and reacting to form a solution containing particles having a ZnSeTe core/ZnSe shell/ZnS shell structure, but is not limited thereto.
  • step (S410) is a step of forming a third solution by mixing the ZnSeTe core formed in step (S300) with a solution containing a second zinc precursor.
  • the solution containing the second zinc precursor may contain a second zinc precursor and a second carboxylic acid-based compound, and may optionally further contain a third organic solvent.
  • the solution containing the second zinc precursor may be heated under vacuum and then heated to a higher temperature under a nitrogen gas atmosphere. Accordingly, it is possible to increase the reaction rate between the ZnSeTe core, the second zinc precursor, and the second selenium precursor.
  • the second zinc precursor, the second carboxylic acid compound, and the third organic solvent that can be used in this step are the same as or different from the first zinc precursor, the first carboxylic acid compound, and the first organic solvent used in step S100, respectively, Each of these examples is as already described in step S100.
  • the contents of the second zinc precursor, the second carboxylic acid-based compound, and the third organic solvent are not particularly limited.
  • the content of the second carboxylic acid-based compound may be about 1 to 5 mol per 1 mol of the second zinc precursor.
  • the content of the third organic solvent may be about 0 to 50,000 ml per 1 mol of the second zinc precursor.
  • the solution containing this second zinc precursor is heated under vacuum and then heated to a higher temperature under a nitrogen atmosphere.
  • the heating temperature and time under vacuum are not particularly limited, and may be heated at, for example, about 100° C. or higher, specifically about 100 to 160° C. for about 0.5 to 24 hours.
  • the temperature and time of raising the temperature in a nitrogen atmosphere are not particularly limited, and the temperature may be raised to, for example, about 200° C. or more, and specifically, about 250 to 350° C.
  • the content of the solution containing the second zinc precursor is not particularly limited, and may be, for example, about 50 to 100,000 parts by weight based on 100 parts by weight of the ZnSeTe core.
  • step (S420) is a step of injecting and reacting a second selenium precursor into a third solution containing a ZnSeTe core and a second zinc precursor prepared in step (S410), and a ZnSe shell is formed on the surface of the ZnSeTe core.
  • a solution containing the first particles having a ZnSeTe core/ZnSe shell structure can be obtained.
  • the second selenium precursor may be added dropwise into the third solution.
  • the second selenium precursor by slowly adding the second selenium precursor, it is possible to form and grow a strong, stable and uniform ZnSe shell on the surface of the ZnSeTe core without being affected by temperature.
  • the second selenium precursor usable in step (S420) is a compound containing selenium, and may be the same as or different from the first selenium precursor used in step S200.
  • it may be selenium-diphenylphosphine selenide, selenium-trioctylphosphine, selenium-tributylphosphine, selenium-triphenylphosphine, and the like, but is not limited thereto. These may be used alone or in combination of two or more.
  • the content of the second selenium precursor may be adjusted according to the thickness and composition of the ZnSe shell.
  • the second selenium precursor and the second zinc precursor in the third solution may be used in a molar ratio of 1:1 to 1:100.
  • the temperature, speed, and time are not particularly limited, and may vary depending on the amount of the second selenium precursor.
  • the second selenium precursor may be added to the third solution for about 6 hours or less at room temperature or higher, specifically, about 15 to 30°C. At this time, the input rate is adjusted according to the content of the second selenium precursor.
  • step (S430) a sulfur precursor is additionally added and reacted to the solution containing the first particles of the ZnSeTe core/ZnSe shell structure formed in the step (S420), thereby forming a ZnS shell on the surface of the ZnSe shell.
  • a solution containing quantum dots having a ZnSeTe core/ZnSe shell/ZnS shell structure can be obtained.
  • the content of Zn and Se in the quantum dot has a concentration gradient that gradually decreases from the center toward the surface (outermost layer), and the content of S has a concentration gradient that gradually increases from the center toward the surface (outermost layer).
  • the introduction rate of the sulfur precursor is not limited, and may be the same, similar to, or faster than the introduction rate of the Se precursor in consideration of the reaction process.
  • the sulfur precursor is added to a solution containing the first particles having a ZnSeTe core/ZnSe shell structure and reacted, a ZnS shell can be formed and grown on the surface of the ZnSe shell.
  • the sulfur precursor usable in the present invention is not particularly limited as long as it is known as a compound containing sulfur in the art, such as sulfur-diphenylphosphine sulfide, sulfur-trioctylphosphine, sulfur-tpibutylphosphine , Sulfur-triphenylphosphine, sulfur-trioctylamine, trimethylsilyl sulfur, ammonium sulfide, sodium sulfide, hexane thiol, octane thiol, decane thiol, dodecane thiol, hexadecane thiol, and the like, but are not limited thereto. These may be used alone or in combination of two or more.
  • the content of the sulfur precursor can be adjusted according to the thickness of the ZnS shell.
  • the sulfur precursor may be mixed with particles of a ZnSeTe core/ZnSe shell structure in the solution of the step (S420) in a molar ratio of 1:0.01 to 10.
  • the thickness of the ZnS shell may be 0.1 to 5 nm.
  • the temperature, speed, and time are not particularly limited, and may vary depending on the amount of the sulfur precursor added.
  • the sulfur precursor may be added to the solution obtained in step (S420) for about 6 hours or less at room temperature or higher, specifically, about 15 to 30 °C. At this time, the input rate is adjusted according to the content of the sulfur precursor.
  • the quantum dots formed through the step (S400) may be purified.
  • an anti-solvent is added to the quantum dots formed in step (S400) to precipitate the quantum dots, and then the ZnSeTe core particles may be separated. This purification process may be repeatedly performed one or more times.
  • the quantum dots are cooled to room temperature, specifically about 23 to 28° C., thereby preventing the quantum dots from becoming excessively large. Accordingly, the particle diameter of the quantum dot particles may be uniform.
  • anti-solvents examples include acetone, ethanol, methanol, butanol, propanol, isopropyl alcohol, tetrahydrofuran, dimethyl sulfoxide, dimethylformamide, and the like, and these are used alone or in combination of two or more. I can.
  • the method of separating the quantum dots is not particularly limited as long as it is known as a liquid-solid separation method in the art, and includes, for example, a centrifugal separation method.
  • the quantum dots may be redispersed in a non-polar solvent and stored.
  • the quantum dots since they are colloidally dispersed in a non-polar solvent, they can be stably stored.
  • non-polar solvents that can be used at this time include hexane, benzene, xylene, toluene, octane, chloroform, chlorobenzene, tetrahydrofuran (THF), methylene chloride, 1,4 -Dioxane (1,4-dioxane), diethyl ether (diethyl ether), cyclohexane, dichlorobenzene, and the like, but are not limited thereto.
  • the quantum dots of the present invention manufactured according to the above-described method include a ZnSeTe core, and at least one layer of a shell, and, unlike conventional ZnSeTe-based quantum dots, have an emission wavelength of about 445 nm or more, specifically about 445 to 500 nm. . Further, the quantum dot according to the present invention may have a full width at half maximum (FWHM) of about 30 nm or less, an average particle diameter of about 5 to 20 nm, and a quantum efficiency of about 75% or more.
  • FWHM full width at half maximum
  • the quantum dot of the present invention is a ZnSeTe core; And a ZnSe shell and a ZnS shell continuously formed on the ZnSeTe core.
  • each shell has a layered gradient composition. That is, Zn, Se, and S in each shell may have different contents.
  • the Zn and Se content has a concentration gradient that gradually decreases from the center of the quantum dot to the surface (outermost layer) side
  • the content of S is a concentration gradient that gradually increases from the center to the surface (outermost layer) side.
  • the ZnSeTe core may have a Te content of more than about 0.1 part by weight and 1 part by weight or less based on 100 parts by weight of Se. Accordingly, the quantum dots of the present invention may have an emission wavelength of about 445 nm or more.
  • Such quantum dots can be variously applied to various electronic devices such as light emitting diode (LED) displays, organic light emitting diode (OLED) displays, sensors, imaging sensors, solar cells, and the like.
  • LED light emitting diode
  • OLED organic light emitting diode
  • a first solution was formed by adding 20 mmol of Zn acetate[Zn(CH 3 COO) 2 ] to a solution of 100 ml of oleic acid 60 mmol and trioctylamine(TOA) (boiling point at 1 atm: about 365 ⁇ 367 °C). After that, the first solution was heated at 120° C. for 120 minutes under vacuum, and then heated to a temperature of about 300° C. in a nitrogen gas atmosphere.
  • TOA trioctylamine
  • Se precursor is formed by dissolving 2 mmol of selenium (Se) powder in 2 ml of diphenylphosphine, and 0.1 mmol of telenium (Te) powder is dissolved in 0.5 ml of Trioctylphosphine to form a Te precursor, and then the Se precursor and the Te precursor are 1: The mixture was mixed at 0.01 molar ratio to obtain a first mixture. Thereafter, TOA was mixed with the first mixture in a volume ratio of 1:1 to obtain a second solution. The second solution was slowly injected into the heated first solution using an injection pump and reacted at 300° C.
  • Zn precursor-containing solution 20 mmol of Zn acetate was added to a solution in which 60 mmol of oleic acid and 100 ml of trioctylamine (TOA) were mixed to form a Zn precursor-containing solution, and the Zn precursor-containing solution was heated at 120° C. for 120 minutes under vacuum, and then, The temperature was raised to a temperature of about 280 °C in a nitrogen atmosphere. Thereafter, the ZnSeTe core synthesized in Example 1-1 was added to the 280° C. Zn precursor-containing solution to obtain a third solution. Subsequently, 0.13 M Se precursor was injected (injected) into the third solution for 4 hours using an injection pump to form a ZnSe shell on the surface of the ZnSeTe core.
  • TOA trioctylamine
  • Example 1-1 when the second solution was slowly injected into the first solution, a ZnSeTe core was performed in the same manner as in Example 1-1, except that 0.3 ml of a halide solution (containing HF) was added at regular intervals. Was synthesized.
  • Quantum dots were manufactured in the same manner as in Example 1-2, except that the ZnSeTe core synthesized in Example 2-1 was used instead of the ZnSeTe core of Example 1-1 used in Example 1-2. .
  • Quantum dots were manufactured in the same manner as in Example 1-2, except that the ZnSeTe core synthesized in Comparative Example 1-1 was used instead of the ZnSeTe core of Example 1-1 used in Example 1-2. .
  • a ZnSeTe core was synthesized.
  • Quantum dots were manufactured in the same manner as in Example 1-2, except that the ZnSeTe core synthesized in Comparative Example 2-1 was used instead of the ZnSeTe core of Example 1-1 used in Example 1-2. .
  • Example 1-1 instead of the second solution, a mixture of the first mixture and water (polarity: 1, boiling point at 1 atm: 100° C.) (1:1 volume ratio) was used. In the same manner as in 1-1, the ZnSeTe core was synthesized. However, the mixed solution was not mixed with the first solution and phase-separated, and some components (Se precursor) in the mixed solution were solidified and could not be injected, so that the ZnSeTe core could not be synthesized.
  • polarity 1, boiling point at 1 atm: 100° C.
  • Example 1-1 Except for using a mixture (1:1 volume ratio) of the first mixture and Toluene (polarity: 0.099, boiling point at 1 atm: about 110 to 111 °C) in Example 1-1 instead of the second solution in Example 1-1 , To synthesize a ZnSeTe core by performing the same as in Example 1-1. However, when the mixed solution was injected into the first solution, the reactor was exploded due to the vapor of Toluene, so that the ZnSeTe core could not be synthesized.
  • polarity 0.099, boiling point at 1 atm: about 110 to 111 °C
  • the emission peak (PL peak), half width (FWHM), and quantum efficiency (QE) were measured at an excitation wavelength of 370 nm using a wavelength equipment of Otsuka QE2100. And the results are shown in Table 1 and FIG. 1 below. At this time, each quantum dot was measured while being dispersed in octane.
  • Both of the quantum dots of Examples 1 and 2 had emission peaks of 445 nm or more, whereas the emission peaks of Comparative Examples 1 and 2 were less than 445 nm.
  • both of the quantum dots of Examples 1 and 2 had a half width as small as 17 nm or less, and a quantum efficiency as high as 75% or more.
  • the quantum dots synthesized according to the present invention had an emission wavelength of 445 nm or more while having a uniform particle diameter of the core.
  • the quantum dots synthesized using the halide solution according to the present invention can further improve the quantum efficiency compared to the quantum dots without the halide solution.

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Abstract

The present invention relates to a method for manufacturing quantum dots and quantum dots manufactured thereby, the method for manufacturing quantum dots comprising the steps: heating a first solution containing a first zinc precursor, a first carboxylic acid-based compound, and a first organic solvent; adding a first mixture of a first selenium (Se) precursor and a telenium (Te) precursor to a second organic solvent to form a second solution; mixing the heated first solution and the second solution to form a ZnSeTe core; and forming at least one layered shell on the ZnSeTe core, wherein the difference in polarity index of the second organic solvent from the first organic solvent is in the range of 0-0.4.

Description

양자점의 제조방법, 및 이에 의해 제조된 양자점Method of manufacturing quantum dots, and quantum dots manufactured thereby
본 발명은 양자점의 제조방법 및 이에 의해 제조된 양자점에 관한 것이다.The present invention relates to a method of manufacturing a quantum dot and a quantum dot manufactured thereby.
양자점(quantum dot, QD)은 수 나노 내지 수십 나노 크기의 결정 구조를 가진 물질로, 나노 입자의 크기 및 조성 성분을 제어함에 따라 밴드갭 조절이 쉽고, 다양한 파장의 빛을 구현할 수 있으며, 또 독특한 전기적, 자기적, 광학적, 화학적, 기계적 특성을 가질 수 있다. 이러한 양자점은 발광 다이오드(LED), 유무기 하이브리드 전기 발광소자, 무기 전기 발광 소자, 태양전지, 트랜지스터 등의 각종 소자에 적용될 수 있다.Quantum dot (QD) is a material having a crystal structure of several nano to tens of nanometers, and it is easy to adjust the band gap by controlling the size and composition of nanoparticles, and can realize light of various wavelengths. It can have electrical, magnetic, optical, chemical, and mechanical properties. These quantum dots can be applied to various devices such as light-emitting diodes (LEDs), organic-inorganic hybrid electroluminescent devices, inorganic electroluminescent devices, solar cells, and transistors.
예를 들어, 양자점 TV와 같은 양자점이 적용된 LED 디스플레이는 청색 발광하는 LED를 광원으로 사용하며, 양자점은 소정의 파장을 갖는 빛을 흡수하여 다른 파장을 갖는 빛으로 방출하는 양자점-폴리머 복합체 시트(QD 시트)의 형태로 포함된다. 이러한 양자점이 적용된 LED 디스플레이는 일반적인 LED 디스플레이의 작동 원리와 동일한 반면, 색 순도 및 효율이 우수하여 주목을 받고 있다. For example, an LED display to which a quantum dot is applied, such as a quantum dot TV, uses a blue-emitting LED as a light source, and the quantum dot absorbs light having a predetermined wavelength and emits light having a different wavelength-a quantum dot-polymer composite sheet (QD It is included in the form of a sheet). The LED display to which such quantum dots are applied is attracting attention because of its excellent color purity and efficiency, while the same as the general operating principle of LED displays.
또한, OLED TV와 같이, 양자점이 적용된 OLED 디스플레이도, 종래 OLED와 달리, 색 재현율 및 색 순도가 우수하기 때문에, 차세대 발광 디스플레이로 각광을 받고 있다. In addition, OLED displays to which quantum dots are applied, like OLED TVs, are in the spotlight as next-generation light emitting displays because, unlike conventional OLEDs, they have excellent color reproduction and color purity.
그러나, 양자점을 이용하여 청색 발광하는 데에 한계가 있다. 게다가, 청색 발광 양자점으로는 Cd계열 양자점이 대부분이고, 비(非)-Cd계열 양자점으로는 ZnSe계 양자점이 알려졌으나, 이의 발광 파장은 약 420~430 nm으로, 약 440 nm 이상인 ZnSe계 양자점은 아직 개발되지 못하고 있다. 게다가, 종래 ZnSe계 양자점은 양자 효율이 낮기 때문에, 고효율의 자발광 TV용 소재에 사용되기 어려웠다. However, there is a limitation in emitting blue light using quantum dots. In addition, most of the blue light-emitting quantum dots are Cd-based quantum dots, and ZnSe-based quantum dots are known as non-Cd-based quantum dots, but their emission wavelength is about 420 to 430 nm, and ZnSe-based quantum dots with more than about 440 nm are It has not been developed yet. In addition, since conventional ZnSe-based quantum dots have low quantum efficiency, it has been difficult to be used for high-efficiency self-luminous TV materials.
본 발명의 목적은 양자점을 합성함에 있어서 ZnSeTe 코어의 입경을 균일하게 제어하여 발광 파장이 445 ㎚ 이상이면서, 양자 효율이 높은 양자점을 제조할 수 있는 방법을 제공하는 것이다.An object of the present invention is to provide a method for manufacturing quantum dots having a light emission wavelength of 445 nm or more and having high quantum efficiency by uniformly controlling the particle diameter of a ZnSeTe core in synthesizing quantum dots.
또, 본 발명의 다른 목적은 발광 파장이 445 ㎚ 이상이면서, 양자 효율이 높은 양자점을 제공하는 것이다.In addition, another object of the present invention is to provide a quantum dot having a light emission wavelength of 445 nm or more and high quantum efficiency.
전술한 목적을 달성하기 위해서, 본 발명은 제1 아연 전구체, 제1 카르복실산계 화합물 및 제1 유기 용매를 포함하는 제1 용액을 가열하는 단계; 제1 셀레늄(Se) 전구체와 텔레늄(Te) 전구체의 제1 혼합물을, 제2 유기 용매에 투입하여 제2 용액을 형성하는 단계; 상기 가열된 제1 용액과 상기 제2 용액을 혼합하여 ZnSeTe 코어를 형성하는 단계; 및 상기 ZnSeTe 코어 상에 적어도 1층의 쉘을 형성하는 단계를 포함하고, 상기 제2 유기 용매는 상기 제1 유기 용매와의 극성도(polarity index) 차이가 0 내지 0.4 범위인, 양자점의 제조방법을 제공한다.In order to achieve the above object, the present invention includes heating a first solution including a first zinc precursor, a first carboxylic acid compound, and a first organic solvent; Forming a second solution by injecting a first mixture of a first selenium (Se) precursor and a telenium (Te) precursor into a second organic solvent; Mixing the heated first solution and the second solution to form a ZnSeTe core; And forming a shell of at least one layer on the ZnSeTe core, wherein the second organic solvent has a difference in polarity index with the first organic solvent in the range of 0 to 0.4. Provides.
또, 본 발명은 전술한 방법에 의해 제조되고, ZnSeTe 코어, 및 적어도 1층의 쉘을 포함하되, 445 ㎚ 이상의 발광 파장을 갖는 양자점을 제공한다.In addition, the present invention provides a quantum dot having an emission wavelength of 445 nm or more, including a ZnSeTe core, and at least one layer of a shell, manufactured by the above-described method.
본 발명은 ZnSeTe 코어의 입경을 균일하게 제어함으로써, 발광 파장이 445 ㎚ 이상이면서, 양자 효율이 높은 양자점을 제조할 수 있다.In the present invention, by uniformly controlling the particle diameter of the ZnSeTe core, quantum dots having a light emission wavelength of 445 nm or more and high quantum efficiency can be manufactured.
도 1은 실시예 1 및 비교예 2에서 각각 제조된 양자점의 발광 스펙트럼을 나타낸 그래프이다.1 is a graph showing emission spectra of quantum dots prepared in Example 1 and Comparative Example 2, respectively.
이하, 본 발명에 대해 설명한다.Hereinafter, the present invention will be described.
본 발명에서는 양자점을 제조함에 있어, 아연 전구체-함유 용액에 사용된 유기 용매와 극성도가 동일하거나 유사한 유기 용매를, 셀레늄 전구체 및 텔레늄 전구체와 함께 아연 전구체-함유 용액에 투입하고 반응시켜 ZnSeTe 코어를 합성한다. 이로써, 본 발명은 발광 파장이 445 ㎚ 이상이고, 양자 효율이 높은 양자점을 제조할 수 있다.In the present invention, in manufacturing a quantum dot, an organic solvent having the same or similar polarity as the organic solvent used in the zinc precursor-containing solution is added to the zinc precursor-containing solution together with the selenium precursor and the telenium precursor and reacted to form a ZnSeTe core. To synthesize. Accordingly, in the present invention, a quantum dot having a light emission wavelength of 445 nm or more and having high quantum efficiency can be manufactured.
본 발명의 제1 실시예에 따르면, 양자점의 제조방법은 제1 아연 전구체, 제1 카르복실산계 화합물 및 제1 유기 용매를 포함하는 제1 용액을 가열하는 단계; 제1 셀레늄(Se) 전구체와 텔레늄(Te) 전구체의 제1 혼합물을, 제2 유기 용매에 투입하여 제2 용액을 형성하는 단계; 상기 가열된 제1 용액과 상기 제2 용액을 혼합하여 ZnSeTe 코어를 형성하는 단계; 및 상기 ZnSeTe 코어 상에 적어도 1층의 쉘을 형성하는 단계를 포함하되, 상기 제2 유기 용매는 상기 제1 유기 용매와의 극성도(polarity index) 차이가 0 내지 0.4 범위이다.According to a first embodiment of the present invention, a method of manufacturing a quantum dot includes heating a first solution including a first zinc precursor, a first carboxylic acid compound, and a first organic solvent; Forming a second solution by injecting a first mixture of a first selenium (Se) precursor and a telenium (Te) precursor into a second organic solvent; Mixing the heated first solution and the second solution to form a ZnSeTe core; And forming a shell of at least one layer on the ZnSeTe core, wherein the second organic solvent has a difference in polarity index with the first organic solvent in the range of 0 to 0.4.
이하, 본 발명에 따라 양자점을 제조하는 방법의 각 단계에 대하여 설명한다.Hereinafter, each step of the method of manufacturing a quantum dot according to the present invention will be described.
(1) 제1 용액의 준비 및 가열 단계(1) Preparation and heating step of the first solution
먼저, 제1 아연(Zn) 전구체, 제1 카르복실산계 화합물 및 제1 유기 용매를 포함하는 제1 용액을 준비한 후 상기 제1 용액을 가열한다(이하, 'S100 단계'라 함).First, after preparing a first solution including a first zinc (Zn) precursor, a first carboxylic acid compound, and a first organic solvent, the first solution is heated (hereinafter referred to as'step S100').
본 발명의 일례에 따르면, 상기 S100 단계는 (S110) 제1 아연 전구체 및 제1 카르복실산계 화합물을, 제1 유기 용매에 투입하여 제1 용액을 준비하는 단계; 및 (S120) 상기 제1 용액을 진공하에서 가열한 다음, 질소 가스 분위기하에서 더 높은 온도로 승온시키는 단계를 포함할 수 있는데, 이에 한정되지 않는다. According to an example of the present invention, the step S100 includes (S110) preparing a first solution by introducing a first zinc precursor and a first carboxylic acid-based compound into a first organic solvent; And (S120) heating the first solution under vacuum and then raising the temperature to a higher temperature under a nitrogen gas atmosphere, but is not limited thereto.
본 발명에서 사용 가능한 제1 아연 전구체는 아연 금속 자체이거나 또는 아연(Zn)을 함유하는 화합물로서, 당 업계에 통상적으로 알려진 것이라면 특별히 한정되지 않는다. 예를 들어, 아연 아세테이트(zinc acetate), 디메틸아연(dimethyl zinc), 디에틸아연(diethyl zinc), 아연 아세틸아세토네이트(zinc acetylacetonate), 아연 아이오다이드(zinc iodide), 아연 브로마이드(zinc bromide), 아연 클로라이드(zinc chloride), 아연 플루오라이드(zinc fluoride), 아연 카보네이트(zinccarbonate), 아연 시아나이드(zinc cyanide), 아연 나이트레이트(zinc nitrate), 아연 옥사이드(zinc oxide), 아연 퍼옥사이드(zinc peroxide), 아연 퍼클로레이트(zinc perchlorate), 아연 설페이트(zinc sulfate) 등이 있는데, 이에 한정되지 않는다. 이들은 단독으로 사용되거나 2종 이상이 혼합되어 사용될 수 있다. 일례에 따르면, 아연 전구체는 아연 아세테이트일 수 있다.The first zinc precursor usable in the present invention is not particularly limited as long as it is a zinc metal itself or a compound containing zinc (Zn), as long as it is commonly known in the art. For example, zinc acetate, dimethyl zinc, diethyl zinc, zinc acetylacetonate, zinc iodide, zinc bromide , Zinc chloride, zinc fluoride, zinc carbonate, zinc cyanide, zinc nitrate, zinc oxide, zinc peroxide peroxide), zinc perchlorate, zinc sulfate, and the like, but are not limited thereto. These may be used alone or in combination of two or more. According to one example, the zinc precursor may be zinc acetate.
본 발명에서 사용 가능한 제1 카르복실산계 화합물은 제1 아연 전구체를 제1 유기 용매 내에 균일하게 분산시킬 수 있는 물질로, 예컨대 올레산(oleic acid), 미리스톨레인산(Myristoleic acid), 팔미톨레인산(Palmitoleic acid), 리놀레인산(Linoleic acid), 에이코사펜타에노인산(Eicosapentaenoic acid, EPA), 도코사펜타에노인산(Docosapentaenoic acid, DPA) 등과 같은 C6~C30의 불포화 지방산; 라우르산(lauric acid), 팔미트산(palmitic acid), 스테아르산(stearic acid), 미리스트산(myristic acid), 엘라이드산(elaidic acid), 에이코사논산(eicosanoic acid), 헤네이코사논산(heneicosanoic acid), 트리코사논산(tricosanoic acid), 도코사논산(docosanoic acid), 테트라코사논산(tetracosanoic acid), 헥사코사논산(hexacosanoic acid), 헵타코사논산(heptacosanoic acid), 옥타코사논산(octacosanoic acid), 시스-13-도코세논산(cis-13-docosenoic acid) 등과 같은 C3~C30의 포화 지방산이 있는데, 이에 한정되지 않는다. 이들은 단독으로 사용하거나 또는 2종 이상이 혼합되어 사용될 수 있다. 일례에 따르면, 카르복실산계 화합물은 올레산(oleic acid) 등과 같은 불포화 지방산일 수 있다.The first carboxylic acid-based compound usable in the present invention is a material capable of uniformly dispersing the first zinc precursor in the first organic solvent, such as oleic acid, myristoleic acid, palmitolein C 6 ~ C 30 unsaturated fatty acids such as Palmitoleic acid, Linoleic acid, Eicosapentaenoic acid (EPA), Docosapentaenoic acid (DPA), and the like; Lauric acid, palmitic acid, stearic acid, myristic acid, elaidic acid, eicosanoic acid, Heneicos Heneicosanoic acid, tricosanoic acid, docosanoic acid, tetracosanoic acid, hexacosanoic acid, heptacosanoic acid, octacosanoic acid There are saturated fatty acids of C 3 to C 30 such as (octacosanoic acid) and cis-13-docosenoic acid, but are not limited thereto. These may be used alone or in combination of two or more. According to an example, the carboxylic acid-based compound may be an unsaturated fatty acid such as oleic acid.
본 발명에서 사용 가능한 제1 유기 용매는 당 업계에서 ZnSeTe 코어 합성에 사용되는 유기 용매라면 제한없이 사용될 수 있고, 예를 들어 헥사데실아민 등의 C6~C22의 1차 알킬아민, 다이옥틸아민 등의 C6~C22의 2차 알킬아민, 트리옥틸아민 등의 C6~C40의 3차 알킬아민 등과 같은 아민계 유기 용매; 피리딘 등의 질소(N)-함유 헤테로고리 화합물; 펜틴(pentene), 헥신(hexene), 헵틴(heptene), 옥타데신(octadecene), 노닌(nonene), 데킨(decene), 운데킨(undecene), 도데킨(dodecene), 트리데킨(tridecene), 테트라데킨(tetradecene), 펜타데킨(pentadecene), 옥테인(octane), 헥사데칸(hexadecane), 옥타데칸(octadecane), 옥타데센(octadecene), 스쿠알렌(squalane) 등과 같은 C5~C40의 지방족 탄화수소; 페닐도데칸, 페닐테트라데칸, 페닐 헥사데칸 등과 같은 C6~C30의 방향족 탄화수소; 트리옥틸포스핀 등과 같이 C6~C22의 알킬기로 치환된 포스핀; 트리옥틸포스핀옥사이드 등과 같이 C6~C22의 알킬기로 치환된 포스핀옥사이드; 페닐 에테르, 벤질 에테르 등과 같이 C12~C22의 방향족 에테르 등이 있는데, 이에 한정되지 않는다. 이들은 단독으로 사용되거나 또는 2종 이상이 혼합되어 사용될 수 있다. 일례에 따르면, 제1 유기 용매는 아민계 유기 용매, 구체적으로 C6~C40의 3차 알킬아민일 수 있다. The first organic solvent usable in the present invention may be used without limitation, as long as it is an organic solvent used in the synthesis of ZnSeTe core in the art, for example, C 6 ~ C 22 primary alkylamines such as hexadecylamine, dioctylamine Amine-based organic solvents such as C 6 to C 22 secondary alkylamines and C 6 to C 40 tertiary alkylamines such as trioctylamine; Nitrogen (N)-containing heterocyclic compounds such as pyridine; Pentene, hexine, heptene, octadecene, nonene, decene, undecene, dodecene, tridecene, tetra Aliphatic hydrocarbons of C 5 to C 40 such as tetradecene, pentadecene, octane, hexadecane, octadecane, octadecene, squalene, and the like; C 6 ~ C 30 aromatic hydrocarbons such as phenyldodecane, phenyltetradecane, and phenyl hexadecane; Phosphine substituted with a C 6 ~ C 22 alkyl group such as trioctylphosphine; Phosphine oxide substituted with a C 6 ~ C 22 alkyl group such as trioctyl phosphine oxide; There are aromatic ethers of C 12 ~ C 22 such as phenyl ether and benzyl ether, but are not limited thereto. These may be used alone or in combination of two or more. According to an example, the first organic solvent may be an amine-based organic solvent, specifically a C 6 ~ C 40 tertiary alkylamine.
(S100) 단계의 제1 용액에서, 제1 아연 전구체, 제1 카르복실산계 화합물 및 제1 유기 용매의 함량은 특별히 한정되지 않는다. 일례에 따르면, 제1 카르복실산계 화합물의 함량은 제1 아연 전구체 1 ㏖당 약 1 내지 5 ㏖ 일 수 있다. 이때, 제1 유기 용매의 함량은 제1 아연 전구체 1 ㏖당 약 100 내지 50,000 ㎖일 수 있다.In the first solution of step (S100), the content of the first zinc precursor, the first carboxylic acid compound, and the first organic solvent is not particularly limited. According to an example, the content of the first carboxylic acid-based compound may be about 1 to 5 mol per 1 mol of the first zinc precursor. In this case, the content of the first organic solvent may be about 100 to 50,000 ml per 1 mol of the first zinc precursor.
이러한 제1 용액은 진공하에서 가열된 후, 질소 분위기하에서 더 높은 온도로 승온될 수 있다.This first solution may be heated under vacuum and then heated to a higher temperature under a nitrogen atmosphere.
상기 진공하에서의 가열 온도 및 시간은 특별히 한정되지 않으며, 예컨대 약 100 ℃ 이상, 구체적으로 약 100 내지 160 ℃에서 약 0.5 내지 24 시간 동안 가열할 수 있다.The heating temperature and time under vacuum are not particularly limited, and may be heated at, for example, about 100° C. or higher, specifically about 100 to 160° C. for about 0.5 to 24 hours.
또, 상기 승온 온도 및 시간은 특별히 한정되지 않으며, 예컨대 약 200 ℃ 이상, 구체적으로 약 250 내지 350 ℃까지 승온시킬 수 있다. In addition, the heating temperature and time are not particularly limited, and for example, the temperature may be raised to about 200° C. or more, specifically about 250 to 350° C.
(2) 제2 용액의 형성 단계(2) Formation step of the second solution
이 단계는 제1 셀레늄(Se) 전구체 및 텔레늄 전구체의 제1 혼합물을 제2 유기 용매에 투입하여 셀레늄 전구체 및 텔레늄 전구체를 함유하는 제2 용액을 형성하는 단계(이하, 'S200 단계'라 함)이다.This step is a step of forming a second solution containing a selenium precursor and a telenium precursor by injecting a first mixture of a first selenium (Se) precursor and a telenium precursor into a second organic solvent (hereinafter referred to as'step S200'). Is).
본 발명에서는 제2 유기 용매로서 전술한 S100 단계에서 사용된 제1 유기 용매와 동일 또는 유사한 극성도(Polarity index)를 갖는 용매, 구체적으로 동일 또는 유사한 극성도를 가지면서, 동일 또는 유사한 비점(Boiling Point, BP)을 갖는 용매, 더 구체적으로 동일한 용매를 사용한다. 여기서, 용매의 극성도(Polarity index)는 일반적으로 용매의 극성 정도를 나타낸 것으로서, 물의 극성도를 1.000으로 할 때 상대 극성도를 의미한다.In the present invention, as the second organic solvent, a solvent having the same or similar polarity index as the first organic solvent used in step S100, specifically the same or similar polarity, and the same or similar boiling point (Boiling Point, BP), more specifically the same solvent is used. Here, the polarity index of the solvent generally indicates the polarity of the solvent, and when the polarity of water is 1.000, it means a relative polarity.
일례에 따르면, 제2 유기 용매는 제1 유기 용매와의 극성도 차이가 약 0 내지 0.4인 용매이다.According to an example, the second organic solvent is a solvent having a difference in polarity with the first organic solvent of about 0 to 0.4.
다른 일례에 따르면, 제2 유기 용매는 제1 유기 용매와의 극성도 차이가 약 0 내지 0.4이면서, 제1 유기 용매와의 비점 차이가 약 0 내지 100 ℃인 용매일 수 있다.According to another example, the second organic solvent may be a solvent having a difference in polarity with the first organic solvent of about 0 to 0.4 and a difference in boiling point with the first organic solvent of about 0 to 100°C.
또 다른 일례에 따르면, 제2 유기 용매는 제1 유기 용매와 동일한 용매일 수 있다.According to another example, the second organic solvent may be the same solvent as the first organic solvent.
이러한 제2 유기 용매는 제2 용액의 보관 및 투입시, 제1 셀레늄 전구체들 및 텔레늄 전구체들의 응집을 방지하면서, 제2 용액을 제1 용액과 혼합하여 반응시킬 때 제2 용액과 제1 용액 간의 상분리를 방지할 뿐만 아니라, 제2 용액과 제1 용액 간의 끓는점(Boiling Point, BP) 차이가 생기는 것을 방지하여 균일한 반응을 유도한다. 따라서, 본 발명에서는 균일한 입경을 가진 ZnSeTe 코어를 합성할 수 있다. 이러한 S200 단계는 S100 단계와 시간적 선후 관계가 없다. 예컨대, S100 단계 이후에 진행될 수도 있으나, S100 단계 이전에 진행되거나 또는 S100 단계와 동시에 별도로 진행될 수도 있다.This second organic solvent prevents aggregation of the first selenium precursors and telenium precursors when storing and injecting the second solution, while mixing the second solution with the first solution to react the second solution and the first solution. In addition to preventing the phase separation of the liver, it also induces a uniform reaction by preventing a difference in boiling point (BP) between the second solution and the first solution. Therefore, in the present invention, a ZnSeTe core having a uniform particle diameter can be synthesized. This step S200 has no temporal precedence relationship with the step S100. For example, it may be performed after step S100, but may be performed before step S100 or may be performed separately at the same time as step S100.
본 단계의 제1 혼합물은 제1 셀레늄 전구체 및 텔레늄 전구체를 포함한다. The first mixture in this step includes a first selenium precursor and a telenium precursor.
여기서, 제1 셀레늄 전구체는 당 업계에서 셀레늄(Se)을 함유하는 화합물로 알려진 것이라면 특별히 한정되지 않으며, 예를 들어 셀렌-디페닐포스핀(Diphenylphosphine selenide), 셀렌-트리옥틸포스핀, 셀렌-트리부틸포스핀, 셀렌-트리페닐포스핀, 디에틸 디셀레나이드(Diethyl diselenide), 디메틸 셀레나이드(Dimethyl selenide), 비스(트리메틸 실리)셀레나이드 [bis(trimethylsilyl)selenide] 등일 수 있다. 이들은 단독으로 또는 2종 이상이 혼합되어 사용될 수 있다.Here, the first selenium precursor is not particularly limited as long as it is known in the art as a compound containing selenium (Se), and for example, selenium-diphenylphosphine selenide, selenium-trioctylphosphine, selenium-tri It may be butylphosphine, selenium-triphenylphosphine, diethyl diselenide, dimethyl selenide, bis(trimethylsilyl)selenide [bis(trimethylsilyl)selenide], and the like. These may be used alone or in combination of two or more.
또, 텔레늄 전구체는 당 업계에서 텔레늄(Te)을 함유하는 화합물로 알려진 것이라면 특별히 한정되지 않으며, 예를 들어 텔루르-트리옥틸포스핀, 텔루르-트리부틸포스핀 또는 텔루르-트리페닐포스핀 등이 있고, 이들은 단독으로 또는 2종 이상이 혼합되어 사용될 수 있다.In addition, the telenium precursor is not particularly limited as long as it is known as a compound containing telenium (Te) in the art, for example, tellurium-trioctylphosphine, tellurium-tributylphosphine, or tellurium-triphenylphosphine. There are, and these may be used alone or in combination of two or more.
이러한 제1 셀레늄 전구체와 텔레늄 전구체가 혼합된 제1 혼합물의 함량은 특별히 한정되지 않으며, 예컨대 제1 혼합물 내 셀레늄과 텔레늄의 전체 함량이 제1 아연 전구체 내 아연 1 mol에 대하여 약 0.05 내지 2 mol 범위일 수 있다. 이때, 제1 셀레늄 전구체와 텔레늄 전구체의 혼합 비율은 특별히 한정되지 않으며, 예컨대 1 : 0.0001~0.029 몰비율, 구체적으로 1 : 0.001~0.01 몰비율일 수 있다. 만약, 제1 셀레늄 전구체의 함량에 대한 텔레늄 전구체의 함량 비율이 0.029 몰비율을 초과할 경우, 발광 파장의 장파장 영역에서의 테일(tail)이 증가하여 청색의 색순도가 저하될 수 있다. The content of the first mixture in which the first selenium precursor and the telenium precursor are mixed is not particularly limited, for example, the total content of selenium and telenium in the first mixture is about 0.05 to 2 with respect to 1 mol of zinc in the first zinc precursor. mol range. In this case, the mixing ratio of the first selenium precursor and the telenium precursor is not particularly limited, and may be, for example, a molar ratio of 1: 0.0001 to 0.029, specifically a molar ratio of 1: 0.001 to 0.01. If the content ratio of the telenium precursor to the content of the first selenium precursor exceeds 0.029 molar ratio, the tail in the long wavelength region of the emission wavelength may increase, and thus the color purity of blue may decrease.
본 단계에서 사용되는 제2 유기 용매의 구체적인 예는 제1 유기 용매에 기재된 바와 동일하기 때문에, 생략한다. 다만, 본 발명의 제2 유기 용매는 전술한 바와 같이, S100 단계에서 사용된 제1 유기 용매와의 극성도 차이가 0 내지 0.4 범위인 용매이고, 구체적으로 제1 유기 용매와의 극성도 차이가 0 내지 0.4 범위이면서 제1 유기 용매와의 비점 차이가 0 내지 100 ℃인 용매이고, 더 구체적으로 제1 유기 용매와 동일한 용매이다. 예를 들어, 제1 유기 용매가 아민계 유기 용매, 구체적으로 3차 알킬아민일 경우, 제1 유기 용매와의 극성도 차이, 나아가 제1 유기 용매와의 비점 차이를 고려하여, 제2 유기 용매도 아민계 유기 용매, 구체적으로 3차 알킬아민일 수 있다. 일례에 따르면, 제1 유기 용매 및 제2 유기 용매는 모두 C6~C40의 알킬기를 함유하는 3차 아민, 구체적으로 트리옥틸아민일 수 있다.Specific examples of the second organic solvent used in this step are the same as those described for the first organic solvent, and thus are omitted. However, as described above, the second organic solvent of the present invention is a solvent having a difference in polarity with the first organic solvent used in step S100 in the range of 0 to 0.4, and specifically, the difference in polarity with the first organic solvent. It is a solvent in the range of 0 to 0.4 and a boiling point difference of 0 to 100°C with the first organic solvent, and more specifically, the same solvent as the first organic solvent. For example, when the first organic solvent is an amine-based organic solvent, specifically a tertiary alkylamine, in consideration of the difference in polarity with the first organic solvent and further, the difference in boiling point with the first organic solvent, the second organic solvent It may also be an amine-based organic solvent, specifically a tertiary alkylamine. According to an example, both the first organic solvent and the second organic solvent may be a tertiary amine containing a C 6 ~ C 40 alkyl group, specifically trioctylamine.
이러한 제2 유기 용매의 함량은 제1 혼합물의 함량에 따라 조절하며, 예컨대 제1 혼합물 100 부피부에 대하여 약 1 내지 100 부피부일 수 있다. The content of the second organic solvent is adjusted according to the content of the first mixture, and may be, for example, about 1 to 100 parts by volume based on 100 parts by volume of the first mixture.
(3) ZnSeTe 코어의 형성 단계(3) Formation step of ZnSeTe core
이 단계는 (S100) 단계에서 가열된 제1 용액과 (S200) 단계에서 형성된 제2 용액을 혼합하고 반응시켜 ZnSeTe 코어를 형성하는 단계이다(이하, 'S300 단계'라 함). This step is a step of mixing and reacting the first solution heated in step (S100) with the second solution formed in step (S200) to form a ZnSeTe core (hereinafter referred to as'step S300').
이때, 가열된 제1 용액에 제2 용액을 투입하거나, 또는 제2 용액에 가열된 제1 용액을 투입하여 가열된 제1 용액과 제2 용액을 혼합한다.At this time, the second solution is added to the heated first solution, or the heated first solution is added to the second solution to mix the heated first solution and the second solution.
상기 제1 용액과 제2 용액의 사용 비율(혼합 비율)은 특별히 한정되지 않으며, 1 : 0.001~1 부피 비율일 수 있다.The use ratio (mixing ratio) of the first solution and the second solution is not particularly limited, and may be 1: 0.001 to 1 volume ratio.
상기 제2 용액의 투입시, 온도, 속도 및 시간은 특별히 한정되지 않으며, 제2 용액의 투입량 등에 따라 달라진다. 예를 들어, 제2 용액은 상온 이상, 구체적으로 약 15 내지 30 ℃의 온도에서 약 6시간 이하 동안 제1 용액에 투입될 수 있다. 이때, 투입 속도는 제2 용액의 함량에 따라 조절할 수 있다.When the second solution is added, the temperature, speed, and time are not particularly limited, and vary depending on the amount of the second solution. For example, the second solution may be added to the first solution for about 6 hours or less at room temperature or higher, specifically, about 15 to 30°C. At this time, the injection rate can be adjusted according to the content of the second solution.
한편, 선택적으로 본 발명에서는 제1 용액과 제2 용액의 혼합시, 할라이드(halide) 용액을 추가적으로 더 투입할 수 있다. Meanwhile, in the present invention, when the first solution and the second solution are mixed, a halide solution may be additionally added.
할라이드 용액은 용매에 할라이드가 분산 또는 녹아 있는 용액으로, 할라이드 용액 내 할라이드가 ZnSeTe 코어의 표면을 에칭하고 코팅함으로써, ZnSeTe 코어의 성장 및 표면이 안정화되어 ZnSeTe 코어의 높은 양자 효율이 유도된다.The halide solution is a solution in which halide is dispersed or dissolved in a solvent, and by etching and coating the surface of the ZnSeTe core with the halide in the halide solution, the growth and surface of the ZnSeTe core are stabilized, leading to high quantum efficiency of the ZnSeTe core.
구체적으로, ZnSeTe 코어의 표면에 존재하는 유기물층(예, 유기 리간드층)의 일부 또는 전부가 할라이드 용액의 할라이드에 의해 제거되고, 대신 할라이드를 구성하는 물질, 예컨대 금속 양이온-할라이드 음이온 또는 탄화수소기-할로겐기가 각각 ZnSeTe 코어의 표면 일부 또는 전부와 결합하여 치환된다. 이로써, 유기 리간드층의 제거로 인한 ZnSeTe 코어 표면의 결함 발생이 할라이드로 형성된 코팅층에 의해 억제되기 때문에, ZnSeTe 코어의 성장 및 표면의 안정성이 향상되어 높은 양자 효율을 갖는 양자점을 얻을 수 있다. 이때, 제조된 양자점은 ZnSeTe 코어와 쉘 간의 계면 일부 또는 전부에 할라이드층이 개재(介在)되어 있다. Specifically, some or all of the organic material layer (e.g., organic ligand layer) present on the surface of the ZnSeTe core is removed by the halide of the halide solution, and instead, a material constituting the halide, such as a metal cation-halide anion or a hydrocarbon group-halogen Each group is substituted by bonding with some or all of the surface of the ZnSeTe core. Accordingly, since the occurrence of defects on the surface of the ZnSeTe core due to the removal of the organic ligand layer is suppressed by the coating layer formed of halide, the growth of the ZnSeTe core and stability of the surface are improved, thereby obtaining quantum dots having high quantum efficiency. At this time, the manufactured quantum dot has a halide layer interposed in some or all of the interface between the ZnSeTe core and the shell.
본 발명에서 사용 가능한 할라이드는 당 업계에 알려진 할로겐화물이라면 특별히 한정되지 않으며, 예컨대 불화물, 염화물, 브롬화물, 요오드화물 등과 같은 무기 할라이드 뿐만 아니라, 할로겐화 탄화수소(예, C1~C12의 알킬 할라이드) 등과 같은 유기 할라이드일 수 있다. 구체적인 예로는, NH4Cl, NH4Br, NH4I, ZnCl2, ZnBr2, ZnI2, CH3Cl, CH3Br, CH3I 등이 있는데, 이에 한정되지 않는다.The halide usable in the present invention is not particularly limited as long as it is a halide known in the art, and not only inorganic halide such as fluoride, chloride, bromide, iodide, etc., but also halogenated hydrocarbons (eg, C 1 ~ C 12 alkyl halide) It may be an organic halide such as. Specific examples include, but are not limited to, NH 4 Cl, NH 4 Br, NH 4 I, ZnCl 2 , ZnBr 2 , ZnI 2 , CH 3 Cl, CH 3 Br, CH 3 I, and the like.
또, 할라이드 용액 내 용매는 할라이드를 용해 또는 분산시킬 수 있는 당 업계에 알려진 극성 용매, 비극성 용매라면, 특별히 한정되지 않는다. In addition, the solvent in the halide solution is not particularly limited as long as it is a polar solvent or non-polar solvent known in the art capable of dissolving or dispersing the halide.
이러한 할라이드 용액의 함량은 특별히 한정되지 않으며, 예컨대 상기 제2 용액 100 부피부를 기준으로 약 0.01 내지 100 부피부 범위일 수 있다. 이때, 할라이드 용액의 농도는 특별히 한정되지 않으며, 예를 들어 할라이드 용액의 총량을 기준으로 약 1 내지 30 중량%, 구체적으로 약 5 내지 20 중량%, 더 구체적으로 약 8 내지 15 중량%일 수 있다. 일례로, 할라이드 용액의 농도는 약 10 중량%일 수 있다.The content of the halide solution is not particularly limited, and may be, for example, in the range of about 0.01 to 100 parts by volume based on 100 parts by volume of the second solution. At this time, the concentration of the halide solution is not particularly limited, and may be, for example, about 1 to 30% by weight, specifically about 5 to 20% by weight, and more specifically about 8 to 15% by weight based on the total amount of the halide solution. . For example, the concentration of the halide solution may be about 10% by weight.
전술한 (S300) 단계에서 형성된 ZnSeTe 코어 입자는 용매 내에 불순물과 함께 용해되어 있다. 따라서, 선택적으로, ZnSeTe 코어 입자를 정제 및 분리할 수 있다. 예를 들어, 상기 (S300) 단계에서 얻은 ZnSeTe 코어 입자를 함유하는 용액에 반용매(anti-solvent)를 투입하여 ZnSeTe 코어 입자를 침전시킨 후 ZnSeTe 코어 입자를 분리시킬 수 있다. 다만, 본 발명에서는 ZnSeTe 코어 입자의 정제시, 반용매와 함께 할라이드(halide)를 투입할 수 있다. 이러한 정제 공정은 1회 이상 반복적으로 수행될 수 있다. The ZnSeTe core particles formed in the above-described step (S300) are dissolved together with impurities in a solvent. Thus, optionally, it is possible to purify and separate the ZnSeTe core particles. For example, after the ZnSeTe core particles are precipitated by adding an anti-solvent to the solution containing the ZnSeTe core particles obtained in step (S300), the ZnSeTe core particles may be separated. However, in the present invention, when purifying the ZnSeTe core particles, a halide may be added together with an anti-solvent. This purification process may be repeatedly performed one or more times.
상기 반용매의 비제한적인 예로는 아세톤, 에탄올, 메탄올, 부탄올, 프로판올, 아이소프로필알코올, 테트라하이드로퓨란, 디메틸설폭시드, 디메틸포름아미드 등이 있고, 이들은 단독으로 또는 2종 이상이 혼합되어 사용될 수 있다. Non-limiting examples of the anti-solvent include acetone, ethanol, methanol, butanol, propanol, isopropyl alcohol, tetrahydrofuran, dimethyl sulfoxide, dimethylformamide, and the like, and these may be used alone or in combination of two or more. have.
상기 ZnSeTe 코어 입자의 분리 방법은 당 업계에서 액체-고체 분리 방법으로 알려진 것이라면 특별히 한정되지 않으며, 예컨대 원심분리법 등이 있다.The method of separating the ZnSeTe core particles is not particularly limited as long as it is known as a liquid-solid separation method in the art, and includes, for example, a centrifugal separation method.
상기 할라이드는 ZnSeTe 코어 입자의 분리 및 정제시, ZnSeTe 코어 표면의 결함이 발생하지 않도록 방지할 뿐만 아니라, ZnSeTe 코어 상에 쉘(shell)이 형성 및 성장하도록 ZnSeTe 코어와 쉘 전구체 간의 반응을 향상시킬 수 있다.The halide not only prevents defects on the surface of the ZnSeTe core from occurring when the ZnSeTe core particles are separated and purified, but also improves the reaction between the ZnSeTe core and the shell precursor so that a shell is formed and grown on the ZnSeTe core. have.
본 발명에서 사용 가능한 할라이드로는 무기 할라이드나 유기 할라이드를 제한 없이 사용할 수 있다. 구체적으로, 무기 할라이드는 당 분야에서 알려진 할로겐(X=F, Cl, Br, I 등) 및 1종의 금속을 함유하는 물질로, 구체적으로 금속불화물, 금속염화물, 금속브롬화물, 금속요오드화물 등과 같은 할로겐화 금속염일 수 있다. 예컨대, ZnCl2, ZnBr2, ZnI2, NH4Cl, NH4Br, NH4I 등이 있다. 또, 유기 할라이드는 할로겐화 탄화수소 등일 수 있고, 구체적으로 C1~C12의 알킬 할라이드 등일 수 있으며, 예컨대 CH3Cl, CH3Br, CH3I 등이 있다. 이들은 단독으로 사용되거나, 2종 이상이 혼합되어 사용될 수 있다. 일례에 따르면, 할라이드는 ZnCl2일 수 있다.As the halide usable in the present invention, an inorganic halide or an organic halide may be used without limitation. Specifically, inorganic halide is a material containing halogen (X=F, Cl, Br, I, etc.) and one metal known in the art, and specifically, metal fluoride, metal chloride, metal bromide, metal iodide, etc. It may be the same metal halide salt. For example, ZnCl 2 , ZnBr 2 , ZnI 2 , NH 4 Cl, NH 4 Br, NH 4 I, and the like. In addition, the organic halide may be a halogenated hydrocarbon or the like, specifically, a C 1 ~ C 12 alkyl halide, and the like, such as CH 3 Cl, CH 3 Br, CH 3 I, and the like. These may be used alone or in combination of two or more. According to an example, the halide may be ZnCl 2.
할라이드의 함량은 특별히 한정되지 않으며, 예컨대 ZnSeTe 코어(core) 분산액의 부피(V1)에 대한 할라이드가 녹아있는 용액(이하, '할라이드 용액')의 부피(V2)의 비율(V2/V1)은 약 0.1 내지 5일 수 있으며, 이때 상기 할라이드 용액 내 할라이드의 함유량은 약 0.1 wt% 이상이며, 용해도 한계까기 할라이드를 용해시킬 수 있다.The content of halide is not particularly limited, for example, the ratio of the volume (V 2 ) of the solution in which the halide is dissolved (hereinafter,'halide solution') to the volume (V 1 ) of the ZnSeTe core dispersion (V 2 /V 1 ) may be about 0.1 to 5, and the halide content in the halide solution is about 0.1 wt% or more, and the halide can be dissolved up to the solubility limit.
또 필요에 따라, 상기에서 분리된 ZnSeTe 코어 입자는 비극성 용매에 재분산시킬 수 있다. 이로써, ZnSeTe 코어 입자는 비극성 용매 내에서 콜로이드상으로 분산되어 존재하기 때문에, 안정적으로 보관될 수 있다. 이때 사용 가능한 비극성 용매의 예로는 헥산(hexane), 벤젠, 자일렌 (xylene), 톨루엔(toluene)，옥테인, 클로로포름(chloroform), 클로로벤젠, 테트라히드로푸란(THF), 염화메틸렌, 1,4-디옥세인(1,4-dioxane), 디에틸에테르(diethyl ether), 사이클로헥세인, 디클로로벤젠 등이 있는데, 이에 한정되지 않는다.Also, if necessary, the ZnSeTe core particles separated above may be redispersed in a non-polar solvent. As a result, since the ZnSeTe core particles are colloidally dispersed and present in a non-polar solvent, they can be stably stored. Examples of non-polar solvents that can be used at this time include hexane, benzene, xylene, toluene, octane, chloroform, chlorobenzene, tetrahydrofuran (THF), methylene chloride, 1,4 -Dioxane (1,4-dioxane), diethyl ether (diethyl ether), cyclohexane, dichlorobenzene, and the like, but are not limited thereto.
(4) 쉘의 형성 단계(4) the formation stage of the shell
본 단계는 (S300) 단계에서 형성된 ZnSeTe 코어 상에 적어도 1층의 쉘을 형성하고 성장시키는 단계(이하, 'S400 단계'라 함)로, 당 업계에서 양자점의 코어 상에 쉘을 형성하고 성장시키는 방법이라면 특별히 한정되지 않는다. 이때, 쉘 형성 공정은 각 쉘의 성분, 두께 및 쉘의 층수에 따라 적절히 선택될 수 있다.This step is a step of forming and growing a shell of at least one layer on the ZnSeTe core formed in step (S300) (hereinafter referred to as'step S400'), in which a shell is formed and grown on the core of quantum dots in the industry. If it is a method, it is not particularly limited. In this case, the shell formation process may be appropriately selected according to the component, thickness, and number of layers of each shell.
일례에 따르면, S400 단계는 (S410) 상기 (S300) 단계에서 형성된 ZnSeTe 코어를, 제2 아연 전구체를 함유하는 용액과 혼합하여 제3 용액을 형성하는 단계; (S420) 제2 셀레늄 전구체를 상기 제3 용액에 투입하고 반응시켜 ZnSeTe 코어/ZnSe 쉘 구조의 제1 입자를 함유하는 용액을 형성하는 단계; 및 (S430) 황 전구체를 상기 제1 입자를 함유하는 용액에 투입하고 반응시켜 ZnSeTe 코어/ZnSe 쉘/ZnS 쉘 구조의 입자를 함유하는 용액을 형성하는 단계를 포함할 수 있는데, 이에 한정되지 않는다.According to an example, step S400 may include forming a third solution by mixing the ZnSeTe core formed in step S410 with a solution containing a second zinc precursor; (S420) adding a second selenium precursor to the third solution and reacting to form a solution containing first particles having a ZnSeTe core/ZnSe shell structure; And (S430) adding a sulfur precursor to the solution containing the first particles and reacting to form a solution containing particles having a ZnSeTe core/ZnSe shell/ZnS shell structure, but is not limited thereto.
구체적으로, (S410) 단계는 상기 (S300) 단계에서 형성된 ZnSeTe 코어를, 제2 아연 전구체를 함유하는 용액과 혼합하여 제3 용액을 형성하는 단계이다. Specifically, step (S410) is a step of forming a third solution by mixing the ZnSeTe core formed in step (S300) with a solution containing a second zinc precursor.
상기 제2 아연 전구체를 함유하는 용액은 제2 아연 전구체, 및 제2 카르복실산계 화합물을 함유할 수 있고, 선택적으로 제3 유기 용매를 더 함유할 수 있다. 이러한 제2 아연 전구체를 함유하는 용액에 ZnSeTe 코어가 투입되기 전에, 제2 아연 전구체를 함유하는 용액을 진공하에서 가열한 다음, 질소 가스 분위기하에서 더 높은 온도로 승온시킬 수 있다. 이로써, ZnSeTe 코어, 제2 아연 전구체 및 제2 셀레늄 전구체 간의 반응 속도를 높일 수 있다.The solution containing the second zinc precursor may contain a second zinc precursor and a second carboxylic acid-based compound, and may optionally further contain a third organic solvent. Before the ZnSeTe core is added to the solution containing the second zinc precursor, the solution containing the second zinc precursor may be heated under vacuum and then heated to a higher temperature under a nitrogen gas atmosphere. Accordingly, it is possible to increase the reaction rate between the ZnSeTe core, the second zinc precursor, and the second selenium precursor.
본 단계에서 사용 가능한 제2 아연 전구체, 제2 카르복실산계 화합물 및 제3 유기 용매는 각각 S100 단계에서 사용된 제1 아연 전구체, 제1 카르복실산계 화합물 및 제1 유기 용매와 동일하거나 상이하고, 이들 각각의 예는 S100 단계에서 이미 기재된 바와 같다.The second zinc precursor, the second carboxylic acid compound, and the third organic solvent that can be used in this step are the same as or different from the first zinc precursor, the first carboxylic acid compound, and the first organic solvent used in step S100, respectively, Each of these examples is as already described in step S100.
상기 제2 아연 전구체를 함유하는 용액에서, 제2 아연 전구체, 제2 카르복실산계 화합물 및 제3 유기 용매의 함량은 특별히 한정되지 않는다. 일례에 따르면, 제2 카르복실산계 화합물의 함량은 제2 아연 전구체 1 ㏖당 약 1 내지 5 ㏖ 일 수 있다. 이때, 제3 유기 용매의 함량은 제2 아연 전구체 1 ㏖당 약 0 내지 50,000 ㎖일 수 있다.In the solution containing the second zinc precursor, the contents of the second zinc precursor, the second carboxylic acid-based compound, and the third organic solvent are not particularly limited. According to an example, the content of the second carboxylic acid-based compound may be about 1 to 5 mol per 1 mol of the second zinc precursor. In this case, the content of the third organic solvent may be about 0 to 50,000 ml per 1 mol of the second zinc precursor.
이러한 제2 아연 전구체를 함유하는 용액은 진공하에서 가열된 후, 질소 분위기하에서 더 높은 온도로 승온된다.The solution containing this second zinc precursor is heated under vacuum and then heated to a higher temperature under a nitrogen atmosphere.
상기 진공하에서의 가열 온도 및 시간은 특별히 한정되지 않으며, 예컨대 약 100 ℃ 이상, 구체적으로 약 100 내지 160 ℃에서 약 0.5 내지 24 시간 동안 가열할 수 있다.The heating temperature and time under vacuum are not particularly limited, and may be heated at, for example, about 100° C. or higher, specifically about 100 to 160° C. for about 0.5 to 24 hours.
또, 질소 분위기하에서의 승온 온도 및 시간은 특별히 한정되지 않으며, 예컨대 약 200 ℃ 이상, 구체적으로 약 250 내지 350 ℃까지 승온시킬 수 있다. In addition, the temperature and time of raising the temperature in a nitrogen atmosphere are not particularly limited, and the temperature may be raised to, for example, about 200° C. or more, and specifically, about 250 to 350° C.
(S410) 단계에서, 제2 아연 전구체를 함유하는 용액의 함량은 특별히 한정되지 않으며, 예컨대 ZnSeTe 코어 100 중량부를 기준으로 약 50 내지 100,000 중량부일 수 있다.In step (S410), the content of the solution containing the second zinc precursor is not particularly limited, and may be, for example, about 50 to 100,000 parts by weight based on 100 parts by weight of the ZnSeTe core.
이후, (S420) 단계는 상기 (S410) 단계에서 준비된, ZnSeTe 코어 및 제2 아연 전구체를 함유하는 제3 용액에 제2 셀레늄 전구체를 투입하고 반응시키는 단계로, ZnSeTe 코어의 표면에 ZnSe 쉘이 형성됨으로써, ZnSeTe 코어/ZnSe 쉘 구조의 제1 입자를 함유하는 용액을 얻을 수 있다. Thereafter, step (S420) is a step of injecting and reacting a second selenium precursor into a third solution containing a ZnSeTe core and a second zinc precursor prepared in step (S410), and a ZnSe shell is formed on the surface of the ZnSeTe core. Thus, a solution containing the first particles having a ZnSeTe core/ZnSe shell structure can be obtained.
이때, 제2 셀레늄 전구체는 제3 용액 내에 드롭 방식(dropwise)으로 첨가될 수 있다. 이와 같이, 제2 셀레늄 전구체를 천천히 첨가함으로써, 온도에 영향을 받지 않고 ZnSeTe 코어 표면에 견고하고 안정적이며 균일한 ZnSe 쉘을 형성하고 성장시킬 수 있다.In this case, the second selenium precursor may be added dropwise into the third solution. In this way, by slowly adding the second selenium precursor, it is possible to form and grow a strong, stable and uniform ZnSe shell on the surface of the ZnSeTe core without being affected by temperature.
(S420) 단계에서 사용 가능한 제2 셀레늄 전구체는 셀레늄을 함유하는 화합물로, S200 단계에서 사용된 제1 셀레늄 전구체와 동일하거나 상이할 수 있다. 예컨대, 셀렌-디페닐포스핀(Diphenylphosphine selenide), 셀렌-트리옥틸포스핀, 셀렌-트리부틸포스핀, 셀렌-트리페닐포스핀 등일 수 있는데, 이에 한정되지 않는다. 이들은 단독으로 또는 2종 이상이 혼합되어 사용될 수 있다.The second selenium precursor usable in step (S420) is a compound containing selenium, and may be the same as or different from the first selenium precursor used in step S200. For example, it may be selenium-diphenylphosphine selenide, selenium-trioctylphosphine, selenium-tributylphosphine, selenium-triphenylphosphine, and the like, but is not limited thereto. These may be used alone or in combination of two or more.
이러한 제2 셀레늄 전구체의 함량은 ZnSe 쉘의 두께, 성분 등에 따라 조절할 수 있다. 예컨대, 제2 셀레늄 전구체와 제3 용액 내 제2 아연 전구체는 1:1 ~ 1:100 몰비율로 사용될 수 있다. The content of the second selenium precursor may be adjusted according to the thickness and composition of the ZnSe shell. For example, the second selenium precursor and the second zinc precursor in the third solution may be used in a molar ratio of 1:1 to 1:100.
(S420) 단계에서, 제2 셀레늄 전구체를 투입시, 온도, 속도 및 시간은 특별히 한정되지 않으며, 제2 셀레늄 전구체의 투입량 등에 따라 달라질 수 있다. 예를 들어, 제2 셀레늄 전구체는 상온 이상, 구체적으로 약 15 내지 30 ℃의 온도에서 약 6시간 이하 동안 제3 용액에 투입될 수 있다. 이때, 투입 속도는 제2 셀레늄 전구체의 함량에 따라 조절한다.In step (S420), when the second selenium precursor is introduced, the temperature, speed, and time are not particularly limited, and may vary depending on the amount of the second selenium precursor. For example, the second selenium precursor may be added to the third solution for about 6 hours or less at room temperature or higher, specifically, about 15 to 30°C. At this time, the input rate is adjusted according to the content of the second selenium precursor.
이어서, (S430) 단계에서는 상기 (S420) 단계에서 형성된 ZnSeTe 코어/ZnSe 쉘 구조의 제1 입자를 함유하는 용액에, 황 전구체를 추가로 투입하고 반응시킴으로써, ZnSe 쉘의 표면에 ZnS 쉘이 형성되어 ZnSeTe 코어/ZnSe 쉘/ZnS 쉘 구조의 양자점을 함유하는 용액을 얻을 수 있다. 이때, 양자점 내 Zn 및 Se 함량은 중심에서 표면(최외층) 측으로 갈수록 점진적으로 작아지는 농도 구배(gradient)를 가지며, S의 함량은 중심에서 표면(최외층) 측으로 갈수록 점진적으로 커지는 농도 구배를 갖는다.Subsequently, in step (S430), a sulfur precursor is additionally added and reacted to the solution containing the first particles of the ZnSeTe core/ZnSe shell structure formed in the step (S420), thereby forming a ZnS shell on the surface of the ZnSe shell. A solution containing quantum dots having a ZnSeTe core/ZnSe shell/ZnS shell structure can be obtained. At this time, the content of Zn and Se in the quantum dot has a concentration gradient that gradually decreases from the center toward the surface (outermost layer), and the content of S has a concentration gradient that gradually increases from the center toward the surface (outermost layer). .
본 단계에서, 황 전구체의 투입 속도는 한정되지 않으며, 반응 공정을 고려하여 Se 전구체의 투입 속도와 동일, 유사하거나 또는 이보다 더 빠를 수 있다. 이와 같이, 황 전구체를 ZnSeTe 코어/ZnSe 쉘 구조의 제1 입자를 함유하는 용액에 첨가하여 반응시키면, ZnS 쉘이 ZnSe 쉘 표면에 형성되고 성장될 수 있다.In this step, the introduction rate of the sulfur precursor is not limited, and may be the same, similar to, or faster than the introduction rate of the Se precursor in consideration of the reaction process. In this way, when the sulfur precursor is added to a solution containing the first particles having a ZnSeTe core/ZnSe shell structure and reacted, a ZnS shell can be formed and grown on the surface of the ZnSe shell.
본 발명에서 사용 가능한 황 전구체는 당 업계에서 황을 함유하는 화합물로 알려진 것이라면 특별히 한정되지 않으며, 예컨대 설퍼-디페닐포스핀(Diphenylphosphine sulfide), 설퍼-트리옥틸포스핀, 설퍼-트피부틸포스핀, 설퍼-트리페닐포스핀, 설퍼-트리옥틸아민, 트리메틸실릴 설퍼, 황화 암모늄, 황화 나트륨, 헥산 티올, 옥탄 티올, 데칸 티올, 도데칸 티올, 헥사데칸 티올 등이 있는데, 이에 한정되지 않는다. 이들은 단독으로 또는 2종 이상이 혼합되어 사용될 수 있다.The sulfur precursor usable in the present invention is not particularly limited as long as it is known as a compound containing sulfur in the art, such as sulfur-diphenylphosphine sulfide, sulfur-trioctylphosphine, sulfur-tpibutylphosphine , Sulfur-triphenylphosphine, sulfur-trioctylamine, trimethylsilyl sulfur, ammonium sulfide, sodium sulfide, hexane thiol, octane thiol, decane thiol, dodecane thiol, hexadecane thiol, and the like, but are not limited thereto. These may be used alone or in combination of two or more.
이러한 황 전구체의 함량은 ZnS 쉘의 두께 등에 따라 조절할 수 있다. 예컨대, 황 전구체는 상기 (S420) 단계의 용액 내 ZnSeTe 코어/ZnSe 쉘 구조의 입자와 1 : 0.01~10 몰비율로 혼합되어 사용될 수 있다. 이 경우, ZnS 쉘의 두께는 0.1~5 ㎚일 수 있다.The content of the sulfur precursor can be adjusted according to the thickness of the ZnS shell. For example, the sulfur precursor may be mixed with particles of a ZnSeTe core/ZnSe shell structure in the solution of the step (S420) in a molar ratio of 1:0.01 to 10. In this case, the thickness of the ZnS shell may be 0.1 to 5 nm.
(S430) 단계에서, 황 전구체의 투입시, 온도, 속도 및 시간은 특별히 한정되지 않으며, 황 전구체의 투입량 등에 따라 달라질 수 있다. 예를 들어, 황 전구체는 상온 이상, 구체적으로 약 15 내지 30 ℃의 온도에서 약 6시간 이하 동안 (S420) 단계에서 얻은 용액에 투입될 수 있다. 이때, 투입 속도는 황 전구체의 함량에 따라 조절한다.In step (S430), when the sulfur precursor is introduced, the temperature, speed, and time are not particularly limited, and may vary depending on the amount of the sulfur precursor added. For example, the sulfur precursor may be added to the solution obtained in step (S420) for about 6 hours or less at room temperature or higher, specifically, about 15 to 30 °C. At this time, the input rate is adjusted according to the content of the sulfur precursor.
한편, 선택적으로, 본 발명에서는 상기 (S400) 단계를 통해 형성된 양자점을 정제할 수 있다. 예를 들어, 상기 (S400) 단계의 반응 종료 후 냉각시킨 다음, 상기 (S400) 단계에서 형성된 양자점에 반용매(anti-solvent)를 투입하여 양자점을 침전시킨 후 ZnSeTe 코어 입자를 분리시킬 수 있다. 이러한 정제 공정은 1회 이상 반복적으로 수행될 수 있다. Meanwhile, optionally, in the present invention, the quantum dots formed through the step (S400) may be purified. For example, after cooling after the reaction in step (S400) is completed, an anti-solvent is added to the quantum dots formed in step (S400) to precipitate the quantum dots, and then the ZnSeTe core particles may be separated. This purification process may be repeatedly performed one or more times.
상기 양자점의 냉각은 상온, 구체적으로 약 23 내지 28 ℃로 냉각시키는 것으로, 양자점이 과도하게 커지는 현상을 방지할 수 있다. 이에 따라, 양자점 입자의 입경이 균일해질 수 있다. The quantum dots are cooled to room temperature, specifically about 23 to 28° C., thereby preventing the quantum dots from becoming excessively large. Accordingly, the particle diameter of the quantum dot particles may be uniform.
본 발명에서 사용 가능한 반용매의 예로는 아세톤, 에탄올, 메탄올, 부탄올, 프로판올, 아이소프로필알코올, 테트라하이드로퓨란, 디메틸설폭시드, 디메틸포름아미드 등이 있고, 이들은 단독으로 또는 2종 이상이 혼합되어 사용될 수 있다. Examples of anti-solvents that can be used in the present invention include acetone, ethanol, methanol, butanol, propanol, isopropyl alcohol, tetrahydrofuran, dimethyl sulfoxide, dimethylformamide, and the like, and these are used alone or in combination of two or more. I can.
상기 양자점의 분리 방법은 당 업계에서 액체-고체 분리 방법으로 알려진 것이라면 특별히 한정되지 않으며, 예컨대 원심분리법 등이 있다.The method of separating the quantum dots is not particularly limited as long as it is known as a liquid-solid separation method in the art, and includes, for example, a centrifugal separation method.
또 필요에 따라, 상기 양자점을 비극성 용매에 재분산시켜 보관할 수 있다. 이로써, 양자점은 비극성 용매 내에서 콜로이드상으로 분산되어 있기 때문에, 안정적으로 보관할 수 있다. 이때 사용 가능한 비극성 용매의 예로는 헥산(hexane), 벤젠, 자일렌 (xylene), 톨루엔(toluene)，옥테인, 클로로포름(chloroform), 클로로벤젠, 테트라히드로푸란(THF), 염화메틸렌, 1,4-디옥세인(1,4-dioxane), 디에틸에테르(diethyl ether), 사이클로헥세인, 디클로로벤젠 등이 있는데, 이에 한정되지 않는다.In addition, if necessary, the quantum dots may be redispersed in a non-polar solvent and stored. As a result, since the quantum dots are colloidally dispersed in a non-polar solvent, they can be stably stored. Examples of non-polar solvents that can be used at this time include hexane, benzene, xylene, toluene, octane, chloroform, chlorobenzene, tetrahydrofuran (THF), methylene chloride, 1,4 -Dioxane (1,4-dioxane), diethyl ether (diethyl ether), cyclohexane, dichlorobenzene, and the like, but are not limited thereto.
전술한 방법에 따라 제조된 본 발명의 양자점은 ZnSeTe 코어, 및 적어도 1층의 쉘을 포함하는 것으로, 종래 ZnSeTe계 양자점과 달리, 약 445 ㎚ 이상, 구체적으로 약 445 내지 500 ㎚의 발광 파장을 갖는다. 또한, 본 발명에 따른 양자점은 반치폭(Full Width at Half Maximum, FWHM)이 약 30 ㎚ 이하로 작고, 평균 입경이 약 5 내지 20 ㎚이면서, 양자 효율이 약 75 % 이상일 수 있다. The quantum dots of the present invention manufactured according to the above-described method include a ZnSeTe core, and at least one layer of a shell, and, unlike conventional ZnSeTe-based quantum dots, have an emission wavelength of about 445 nm or more, specifically about 445 to 500 nm. . Further, the quantum dot according to the present invention may have a full width at half maximum (FWHM) of about 30 nm or less, an average particle diameter of about 5 to 20 nm, and a quantum efficiency of about 75% or more.
일례에 따르면, 본 발명의 양자점은 ZnSeTe 코어; 및 상기 ZnSeTe 코어 상에 연속적으로 형성된 ZnSe 쉘 및 ZnS 쉘을 포함한다. 이때, 각 쉘은 층상 구배 조성을 갖는다. 즉, 각 쉘 내 Zn, Se 및 S는 서로 다른 함량을 가질 수 있다. 구체적으로, Zn 및 Se 함량은 양자점의 중심에서 표면(최외층) 측으로 갈수록 점진적으로 작아지는 농도 구배(gradient)를 가지며, S의 함량은 중심에서 표면(최외층) 측으로 갈수록 점진적으로 커지는 농도 구배를 갖는다. According to one example, the quantum dot of the present invention is a ZnSeTe core; And a ZnSe shell and a ZnS shell continuously formed on the ZnSeTe core. At this time, each shell has a layered gradient composition. That is, Zn, Se, and S in each shell may have different contents. Specifically, the Zn and Se content has a concentration gradient that gradually decreases from the center of the quantum dot to the surface (outermost layer) side, and the content of S is a concentration gradient that gradually increases from the center to the surface (outermost layer) side. Have.
상기 ZnSeTe 코어는 Te 함량이 Se 100 중량부를 기준으로 약 0.1 중량부 초과, 1 중량부 이하일 수 있다. 이로써, 본 발명의 양자점은 약 445 ㎚ 이상의 발광 파장을 가질 수 있다.The ZnSeTe core may have a Te content of more than about 0.1 part by weight and 1 part by weight or less based on 100 parts by weight of Se. Accordingly, the quantum dots of the present invention may have an emission wavelength of about 445 nm or more.
이와 같은 양자점은 발광 다이오드(light emitting diode, LED) 디스플레이,유기발광 다이오드(OLED) 디스플레이, 센서(sensor), 이미징 센서, 태양전지 등과 같은 각종 전자 소자에 다양하게 적용될 수 있다.Such quantum dots can be variously applied to various electronic devices such as light emitting diode (LED) displays, organic light emitting diode (OLED) displays, sensors, imaging sensors, solar cells, and the like.
이하에서, 실시예를 통하여 본 발명을 보다 상세히 설명한다. 그러나, 이하의 실시예는 본 발명을 예시하기 위한 것일 뿐, 본 발명의 범위가 실시예로 한정되는 것은 아니다.Hereinafter, the present invention will be described in more detail through examples. However, the following examples are for illustrative purposes only, and the scope of the present invention is not limited to the examples.
<실시예 1> - 양자점의 제조<Example 1>-Preparation of quantum dots
1-1. ZnSeTe 코어의 합성1-1. Synthesis of ZnSeTe core
oleic acid 60 mmol 및 trioctylamine(TOA)(1 atm에서의 비점: 약 365~367 ℃) 100 ㎖가 혼합된 용액에 Zn acetate[Zn(CH3COO)2] 20 mmol을 투입하여 제1 용액을 형성한 후, 상기 제1 용액을 진공하에서 120 ℃로 120분 동안 가열한 후 질소 가스 분위기에서 약 300 ℃의 온도까지 승온시켰다. Diphenylphosphine 2 ㎖에 셀레늄(Se) 분말 2 mmol을 용해시켜 Se 전구체를 형성하고, Trioctylphosphine 0.5 ㎖에 텔레늄(Te) 분말 0.1mmol을 용해시켜 Te 전구체를 형성한 다음, Se 전구체와 Te 전구체를 1 : 0.01 몰비로 혼합하여 제1 혼합물을 얻었다. 이후, 상기 제1 혼합물에 TOA를 1:1 부피비로 혼합하여 제2 용액을 얻었다. 상기 제2 용액을 상기 승온된 제1 용액에 주사 펌프를 이용하여 천천히 주사하여 300 ℃에서 120분 동안 반응시켜 ZnSeTe 코어를 합성한 다음, Acetone, Ethanol 및 ZnCl2를 이용하여 ZnSeTe 코어를 원심 분리한 후, 분리된 ZnSeTe 코어를 Hexane에 분산시켜 ZnSeTe 코어가 분산된 분산용액을 얻었다.A first solution was formed by adding 20 mmol of Zn acetate[Zn(CH 3 COO) 2 ] to a solution of 100 ml of oleic acid 60 mmol and trioctylamine(TOA) (boiling point at 1 atm: about 365~367 ℃). After that, the first solution was heated at 120° C. for 120 minutes under vacuum, and then heated to a temperature of about 300° C. in a nitrogen gas atmosphere. Se precursor is formed by dissolving 2 mmol of selenium (Se) powder in 2 ml of diphenylphosphine, and 0.1 mmol of telenium (Te) powder is dissolved in 0.5 ml of Trioctylphosphine to form a Te precursor, and then the Se precursor and the Te precursor are 1: The mixture was mixed at 0.01 molar ratio to obtain a first mixture. Thereafter, TOA was mixed with the first mixture in a volume ratio of 1:1 to obtain a second solution. The second solution was slowly injected into the heated first solution using an injection pump and reacted at 300° C. for 120 minutes to synthesize a ZnSeTe core, and then the ZnSeTe core was centrifuged using Acetone, Ethanol and ZnCl 2. Then, the separated ZnSeTe core was dispersed in Hexane to obtain a dispersion solution in which the ZnSeTe core was dispersed.
1-2. 쉘의 형성1-2. Shell formation
oleic acid 60mmol 및 trioctylamine(TOA) 100 ml가 혼합된 용액에 Zn acetate 20 mmol을 투입하여 Zn 전구체-함유 용액을 형성하고, 상기 Zn 전구체-함유 용액을 진공하에서 120 ℃로 120분 동안 가열한 다음, 질소 분위기에서 약 280 ℃의 온도까지 승온시켰다. 이후, 상기 280 ℃의 Zn 전구체-함유 용액에, 실시예 1-1에서 합성된 ZnSeTe 코어를 투입하여 제3 용액을 얻었다. 이어서, 0.13 M의 Se 전구체를, 주사 펌프를 이용하여 4시간 동안 상기 제3 용액에 투입(주사)하여 ZnSeTe 코어 표면에 ZnSe 쉘을 형성하였다. 이후, 1 M의 S 전구체를 주사 펌프를 이용하여 ZnSeTe 코어/ZnSe 쉘의 입자를 함유하는 용액에 2시간 동안 투입하여 ZnSe 쉘의 표면에 ZnS 쉘을 형성하였다. 반응 종료 후, 상온으로 냉각시킨 다음, Acetone과 Ethanol의 혼합 용액을 투입하고 원심 분리하여 ZnSeTe 코어-ZnSe/ZnS 쉘 구조의 양자점을 제조하였다. 이때, 사용된 0.13 M의 Se 전구체는 Trioctylphosphine에 셀레늄(Se) 분말을 용해시켜 얻은 것이고, 1 M의 S 전구체는 Trioctylphosphine에 황(S) 분말을 용해시켜 얻은 것이었다.20 mmol of Zn acetate was added to a solution in which 60 mmol of oleic acid and 100 ml of trioctylamine (TOA) were mixed to form a Zn precursor-containing solution, and the Zn precursor-containing solution was heated at 120° C. for 120 minutes under vacuum, and then, The temperature was raised to a temperature of about 280 °C in a nitrogen atmosphere. Thereafter, the ZnSeTe core synthesized in Example 1-1 was added to the 280° C. Zn precursor-containing solution to obtain a third solution. Subsequently, 0.13 M Se precursor was injected (injected) into the third solution for 4 hours using an injection pump to form a ZnSe shell on the surface of the ZnSeTe core. Thereafter, 1 M of the S precursor was added to a solution containing particles of the ZnSeTe core/ZnSe shell for 2 hours using an injection pump to form a ZnS shell on the surface of the ZnSe shell. After the reaction was completed, cooled to room temperature, a mixed solution of Acetone and Ethanol was added and centrifuged to prepare a quantum dot having a ZnSeTe core-ZnSe/ZnS shell structure. At this time, the 0.13 M Se precursor used was obtained by dissolving selenium (Se) powder in Trioctylphosphine, and the 1 M S precursor was obtained by dissolving sulfur (S) powder in Trioctylphosphine.
<실시예 2> - 양자점의 제조<Example 2>-Preparation of quantum dots
2-1. ZnSeTe 코어의 합성2-1. Synthesis of ZnSeTe core
실시예 1-1에서 제1 용액에 제2 용액을 천천히 주사할 때, 일정 간격으로 0.3ml의 할라이드 용액(HF 함유)을 넣는 것을 제외하고는, 실시예 1-1과 동일하게 수행하여 ZnSeTe 코어를 합성하였다.In Example 1-1, when the second solution was slowly injected into the first solution, a ZnSeTe core was performed in the same manner as in Example 1-1, except that 0.3 ml of a halide solution (containing HF) was added at regular intervals. Was synthesized.
2-2. 쉘의 형성2-2. Shell formation
실시예 1-2에서 사용된 실시예 1-1의 ZnSeTe 코어 대신 상기 실시예 2-1에서 합성된 ZnSeTe 코어를 사용하는 것을 제외하고는, 실시예 1-2와 동일하게 수행하여 양자점을 제조하였다.Quantum dots were manufactured in the same manner as in Example 1-2, except that the ZnSeTe core synthesized in Example 2-1 was used instead of the ZnSeTe core of Example 1-1 used in Example 1-2. .
<비교예 1> - 양자점의 제조<Comparative Example 1>-Preparation of quantum dots
1-1. ZnSeTe 코어의 합성1-1. Synthesis of ZnSeTe core
실시예 1-1에서 제1 용액에 제2 용액을 천천히 주사하는 대신, 제1 용액에 Se 전구체와 Te 전구체의 혼합물(Se 전구체 : Te 전구체 = 1 : 0.01 몰비)을 한번에 빠르게 주사하는 것을 제외하고는, 실시예 1-1과 동일하게 수행하여 ZnSeTe 코어를 합성하였다. In Example 1-1, instead of slowly injecting the second solution into the first solution, a mixture of Se precursor and Te precursor (Se precursor: Te precursor = 1: 0.01 molar ratio) was rapidly injected into the first solution at once. In the same manner as in Example 1-1, a ZnSeTe core was synthesized.
1-2. 쉘의 형성1-2. Shell formation
실시예 1-2에서 사용된 실시예 1-1의 ZnSeTe 코어 대신 상기 비교예 1-1에서 합성된 ZnSeTe 코어를 사용하는 것을 제외하고는, 실시예 1-2와 동일하게 수행하여 양자점을 제조하였다.Quantum dots were manufactured in the same manner as in Example 1-2, except that the ZnSeTe core synthesized in Comparative Example 1-1 was used instead of the ZnSeTe core of Example 1-1 used in Example 1-2. .
<비교예 2> - 양자점의 제조<Comparative Example 2>-Preparation of quantum dots
2-1. ZnSeTe 코어의 합성2-1. Synthesis of ZnSeTe core
실시예 1-1에서 제1 용액에 제2 용액을 천천히 주사하는 대신, 제1 용액에 Se 전구체와 Te 전구체의 혼합물(Se 전구체 : Te 전구체 = 1 : 0.03 몰비)을 한번에 빠르게 주사하는 것을 제외하고는, 실시예 1-1과 동일하게 수행하여 ZnSeTe 코어를 합성하였다. In Example 1-1, instead of slowly injecting the second solution into the first solution, except for rapidly injecting a mixture of Se precursor and Te precursor (Se precursor: Te precursor = 1: 0.03 molar ratio) to the first solution at once. In the same manner as in Example 1-1, a ZnSeTe core was synthesized.
2-2. 쉘의 형성2-2. Shell formation
실시예 1-2에서 사용된 실시예 1-1의 ZnSeTe 코어 대신 상기 비교예 2-1에서 합성된 ZnSeTe 코어를 사용하는 것을 제외하고는, 실시예 1-2와 동일하게 수행하여 양자점을 제조하였다.Quantum dots were manufactured in the same manner as in Example 1-2, except that the ZnSeTe core synthesized in Comparative Example 2-1 was used instead of the ZnSeTe core of Example 1-1 used in Example 1-2. .
<비교예 3> - 양자점의 제조<Comparative Example 3>-Preparation of quantum dots
실시예 1-1에서 제2 용액 대신, 상기 제1 혼합물과 물(극성도: 1, 1 atm에서의 비점: 100 ℃)의 혼합액(1:1 부피비)을 사용하는 것을 제외하고는, 실시예 1-1과 동일하게 수행하여 ZnSeTe 코어를 합성하고자 하였다. 그러나, 상기 혼합액은 제1 용액과 혼합되지 않고 상분리되었고, 또 상기 혼합액 내 일부 성분(Se 전구체)이 고체화되어 주사할 수 없어 ZnSeTe 코어를 합성할 수 없었다.In Example 1-1, instead of the second solution, a mixture of the first mixture and water (polarity: 1, boiling point at 1 atm: 100° C.) (1:1 volume ratio) was used. In the same manner as in 1-1, the ZnSeTe core was synthesized. However, the mixed solution was not mixed with the first solution and phase-separated, and some components (Se precursor) in the mixed solution were solidified and could not be injected, so that the ZnSeTe core could not be synthesized.
<비교예 4> - 양자점의 제조<Comparative Example 4>-Preparation of quantum dots
실시예 1-1에서 제2 용액 대신, 상기 제1 혼합물과 Toluene(극성도: 0.099, 1 atm에서의 비점: 약 110~111 ℃)의 혼합액(1:1 부피비)을 사용하는 것을 제외하고는, 실시예 1-1과 동일하게 수행하여 ZnSeTe 코어를 합성하고자 하였다. 그러나, 상기 혼합액을 제1 용액에 주사할 때 Toluene의 증기 때문에 반응기의 폭발이 발생하여 ZnSeTe 코어를 합성할 수 없었다.Except for using a mixture (1:1 volume ratio) of the first mixture and Toluene (polarity: 0.099, boiling point at 1 atm: about 110 to 111 °C) in Example 1-1 instead of the second solution in Example 1-1 , To synthesize a ZnSeTe core by performing the same as in Example 1-1. However, when the mixed solution was injected into the first solution, the reactor was exploded due to the vapor of Toluene, so that the ZnSeTe core could not be synthesized.
<실험예 1> <Experimental Example 1>
실시예 1~2 및 비교예 1~2에서 각각 제조된 양자점에 대하여 오츠카 QE2100의 파장장비를 이용하여 여기 파장 370nm으로 발광 피크(PL peak), 반치폭(FWHM) 및 양자 효율(QE)을 각각 측정하였고, 그 결과를 하기 표 1 및 도 1에 나타내었다. 이때, 각 양자점은 옥탄에 분산된 상태에서 측정되었다.For the quantum dots prepared in Examples 1 to 2 and Comparative Examples 1 to 2, respectively, the emission peak (PL peak), half width (FWHM), and quantum efficiency (QE) were measured at an excitation wavelength of 370 nm using a wavelength equipment of Otsuka QE2100. And the results are shown in Table 1 and FIG. 1 below. At this time, each quantum dot was measured while being dispersed in octane.
PL peak (㎚)PL peak (nm) FWHM (㎚)FWHM (nm) QE (%)QE (%)
실시예 1Example 1 447447 1616 7878
실시예 2Example 2 448448 1717 8888
비교예 1Comparative Example 1 435435 1313 5858
비교예 2Comparative Example 2 441441 2121 6666
실시예 1 및 2의 양자점은 모두 발광 피크가 445 ㎚ 이상인 반면, 비교예 1~의 발광 피크는 445 ㎚ 미만이었다. 또한, 실시예 1 및 2의 양자점은 모두 반치폭이 17 ㎚ 이하로 작으면서, 양자 효율이 75 % 이상으로 높았다. Both of the quantum dots of Examples 1 and 2 had emission peaks of 445 nm or more, whereas the emission peaks of Comparative Examples 1 and 2 were less than 445 nm. In addition, both of the quantum dots of Examples 1 and 2 had a half width as small as 17 nm or less, and a quantum efficiency as high as 75% or more.
이와 같이 본 발명에 따라 합성된 양자점은 코어의 입경이 균일하면서 445 ㎚ 이상의 발광 파장을 가진다는 것을 확인할 수 있었다. 또한, 본 발명에 따라 할라이드 용액을 이용하여 합성된 양자점은 할라이드 용액을 이용하지 않은 양자점에 비해 양자 효율이 더 향상될 수 있다는 것을 확인할 수 있었다. As described above, it was confirmed that the quantum dots synthesized according to the present invention had an emission wavelength of 445 nm or more while having a uniform particle diameter of the core. In addition, it was confirmed that the quantum dots synthesized using the halide solution according to the present invention can further improve the quantum efficiency compared to the quantum dots without the halide solution.

Claims (9)

  1. 제1 아연 전구체, 제1 카르복실산계 화합물 및 제1 유기 용매를 포함하는 제1 용액을 가열하는 단계;Heating a first solution comprising a first zinc precursor, a first carboxylic acid compound, and a first organic solvent;
    제1 셀레늄(Se) 전구체와 텔레늄(Te) 전구체의 제1 혼합물을, 제2 유기 용매에 투입하여 제2 용액을 형성하는 단계; Forming a second solution by injecting a first mixture of a first selenium (Se) precursor and a telenium (Te) precursor into a second organic solvent;
    상기 가열된 제1 용액과 상기 제2 용액을 혼합하여 ZnSeTe 코어를 형성하는 단계; 및Mixing the heated first solution and the second solution to form a ZnSeTe core; And
    상기 ZnSeTe 코어 상에 적어도 1층의 쉘을 형성하는 단계Forming at least one layer of shell on the ZnSeTe core
    를 포함하고,Including,
    상기 제2 유기 용매는 상기 제1 유기 용매와의 극성도(polarity index) 차이가 0 내지 0.4 범위인, 양자점의 제조방법.The second organic solvent has a polarity index difference with the first organic solvent in the range of 0 to 0.4.
  2. 제1항에 있어서,The method of claim 1,
    상기 제2 유기 용매는 상기 제1 유기 용매와의 비점(boiling point) 차이가 0 내지 100 ℃ 범위인, 양자점의 제조방법.The second organic solvent has a boiling point difference with the first organic solvent in the range of 0 to 100°C.
  3. 제2항에 있어서,The method of claim 2,
    상기 제2 용매는 상기 제1 유기 용매와 동일한 것인, 양자점의 제조방법.The second solvent is the same as the first organic solvent, the method of manufacturing a quantum dot.
  4. 제1항에 있어서,The method of claim 1,
    상기 제1 용액과 제2 용액의 혼합시, 할라이드(halide) 용액을 추가로 투입하는, 양자점의 제조방법.When the first solution and the second solution are mixed, a halide solution is additionally added.
  5. 제4항에 있어서,The method of claim 4,
    상기 할라이드 용액 내 할라이드는 무기 할라이드 및 유기 할라이드로 이루어진 군에서 선택된 1종 이상인 것인, 양자점의 제조방법.The halide in the halide solution is one or more selected from the group consisting of inorganic halide and organic halide.
  6. 제1항에 있어서,The method of claim 1,
    상기 제1 셀레늄 전구체와 텔레늄 전구체의 혼합 비율은 1 : 0.0001~0.029 몰비율인, 양자점의 제조방법.The mixing ratio of the first selenium precursor and the telenium precursor is 1: 0.0001 ~ 0.029 molar ratio, the method of manufacturing a quantum dot.
  7. 제1항에 있어서,The method of claim 1,
    상기 ZnSeTe 코어를 형성하는 단계 후, After the step of forming the ZnSeTe core,
    상기 ZnSeTe 코어를 할라이드(Halide)를 이용하여 분리하는 단계;Separating the ZnSeTe core using a halide;
    를 더 포함하는, 양자점의 제조방법.A method of manufacturing a quantum dot further comprising a.
  8. 제1항에 있어서,The method of claim 1,
    상기 쉘을 형성하는 단계는,Forming the shell,
    상기 ZnSeTe 코어를 제2 아연 전구체를 함유하는 용액에 투입하여 제3 용액을 형성하는 단계; Forming a third solution by introducing the ZnSeTe core into a solution containing a second zinc precursor;
    제2 셀레늄 전구체를 상기 제3 용액에 투입하고 반응시켜 ZnSeTe 코어/ZnSe 쉘 구조의 제1 입자를 함유하는 용액을 형성하는 단계; 및Adding a second selenium precursor to the third solution and reacting to form a solution containing first particles having a ZnSeTe core/ZnSe shell structure; And
    황 전구체를 상기 제1 입자를 함유하는 용액에 투입하고 반응시켜 ZnSeTe 코어/ZnSe 쉘/ZnS 쉘 구조의 입자를 함유하는 용액을 형성하는 단계Injecting a sulfur precursor into the solution containing the first particles and reacting to form a solution containing particles having a ZnSeTe core/ZnSe shell/ZnS shell structure
    를 포함하는, 양자점의 제조방법.Containing, a method of manufacturing a quantum dot.
  9. 제1항 내지 제8항 중 어느 한 항에 기재된 방법에 의해 제조되고, ZnSeTe 코어, 및 적어도 1층의 쉘을 포함하되, 445 ㎚ 이상의 발광 파장을 갖는 양자점.A quantum dot manufactured by the method according to any one of claims 1 to 8, comprising a ZnSeTe core, and a shell of at least one layer, and having an emission wavelength of 445 nm or more.
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