KR102358680B1 - Preparation method for core-shell quantum dot comprising iii-v core, and quantum dot manufactured thereby - Google Patents

Abstract

(상기 화학식 1에서 R1 및 R2는 서로 동일하거나 동일하지 않은 탄소수가 1 내지 5인 알킬기이고, n은 1 내지 10인 정수이다)The present invention relates to a method for manufacturing a quantum dot of a core-shell structure comprising a group III-V core and a quantum dot prepared thereby, the method for manufacturing a quantum dot according to an embodiment of the present invention includes a group III solution in a solvent represented by the following formula (1) 1 step of adding and stirring a compound including a precursor and zinc (Zn); and a second step of growing a group III-V core by adding and stirring a group V precursor to the stirred solution.
[Formula 1]

(In Formula 1, R1 and R2 are the same as or not identical to each other, and an alkyl group having 1 to 5 carbon atoms, and n is an integer of 1 to 10)

Description

A method for manufacturing a quantum dot of a core-shell structure comprising a group III-V core, and a quantum dot manufactured thereby

The present invention relates to a method for preparing a quantum dot having a core-shell structure including a group III-V core using a glyme solvent having a chelating effect as a high-temperature pyrolysis solvent.

A lot of effort is being made to develop a quantum dot material having semiconductor properties without defects while being manufactured through a simple and economical process. Quantum dot-sized semiconductor particles are being applied to solar cells, light emitting devices, sensors, light emitting indicators, and biodiagnostic reagents. is the material In particular, among semiconductor quantum dot materials, ‘CdSe’ has very excellent light emitting properties and has been developed as a ‘full color’ light emitting material. However, the fatal weakness of this material is that it violates RoHS (Restriction of Hazardous Substances Directives), so products containing this material cannot be sold to the general public. Accordingly, there is a demand for the development of novel quantum dot materials that do not contain Cd atoms. As a material that can replace CdSe, a group II-VI semiconductor, which is the first-generation high-efficiency light emitting device, InP made of group III-V elements is currently the most promising material.

As a method of synthesizing InP quantum dots, high-temperature pyrolysis is being used. This is a method of forming InP nanoparticles using thermal decomposition of materials by adding surfactant, indium (In) and phosphorus (P) source, and heat-treating it at a high temperature. In this case, tri-n-octylphosphine oxide (TOPO) has been conventionally used, and a solvent commonly used at present is 1-octadecene (ODE). However, when synthesizing using these two solvents, defects often occurred in the InP core, resulting in low luminescence properties. ODE is difficult to completely remove from the ligand region after reaction, and TOPO has a problem of decomposition during high-temperature thermal decomposition.

The biggest challenge that group III-V quantum dot materials such as InP quantum dots have to overcome is to increase luminous efficiency. When manufactured according to a conventional manufacturing method, the photoluminescent quantum yield (PLQY) is very low. The reason why the quantum yield is low is because of the defect structure created in the III-V group nanocrystals during manufacturing. In particular, since group III elements need to thoroughly exclude oxygen and moisture when manufacturing quantum dots, a defect structure occurs in the process to avoid oxygen and moisture. However, while minimizing these defects, the reality is that there is no simple and economical process at the same time. In particular, the process of manufacturing group III-V quantum dots is very difficult than manufacturing quantum dots such as group II-VI.

Republic of Korea Patent Publication No. 10-1029242 Republic of Korea Patent Publication No. 10-2013-0046849

The present invention is free from defects and in order to produce a quantum dot including a III-V core having excellent luminous efficiency, a glyme solvent specialized for the production of a quantum dot including a III-V core is used in a large amount in one reactor. An object of the present invention is to provide a simple and economical manufacturing method that can be produced.

A quantum dot manufacturing method comprising a group III-V core according to an embodiment of the present invention comprises: a first step of adding and stirring a compound containing a group III precursor and zinc (Zn) to a solvent represented by the following formula (1); and a second step of growing a group III-V core by adding and stirring a group V precursor to the stirred solution.

[Formula 1]

(In Formula 1, R1 and R2 are the same as or not identical to each other, and an alkyl group having 1 to 5 carbon atoms, and n is an integer of 1 to 10)

In the method for manufacturing a quantum dot including a group III-V core according to an embodiment of the present invention, in the solvent represented by Formula 1, R1 and R2 may be a methyl (methyl) group.

In the method for producing quantum dots including a group III-V core according to an embodiment of the present invention, the solvent represented by Chemical Formula 1 in step 1 is monoglyme (n=1), diglyme (n=2), triglyme (n=3), tetraglyme (n=4) and mixtures thereof.

In the method for manufacturing a quantum dot including a group III-V core according to an embodiment of the present invention, the group III element of the group III precursor of the first step may be indium (In).

In the quantum dot manufacturing method comprising a group III-V core according to an embodiment of the present invention, the group III precursor of the first step is an indium (In) precursor, In ₂ O ₃ , In ₂ S ₃ , InF ₃ , InCl ₃ , InBr ₃ , InI ₃ , In(CH ₃ CO ₂ ) ₃ , In(OH) ₃ , In(NO ₃ ) ₃ , In(OH) ₃ , In(CN) ₃ , In(ClO ₃ ) ₃ , In(PO ₄ ) and mixtures thereof.

In the quantum dot manufacturing method comprising a group III-V core according to an embodiment of the present invention, the compound containing zinc (Zn) is ZnF ₂ , ZnCl ₂ , ZnBr ₂ , ZnI ₂ , Zn(CH ₃ CO ₂ ) ₂ , Zn(OH) ₂ , Zn(NO ₃ ) ₂ , Zn(SO ₄ ), Zn(CN) ₂ , Zn(ClO ₃ ) ₂ , Zn ₃ (PO ₄ ) ₂ , and mixtures thereof have.

In the quantum dot manufacturing method including a group III-V core according to an embodiment of the present invention, when the group III element of the group III precursor in step 1 is indium (In), the mixing molar ratio of indium (In) and zinc (Zn) may be 1:4 to 1:20.

In the method for manufacturing a quantum dot including a group III-V core according to an embodiment of the present invention, step 1 may further add and stir oleylamine.

In the method for producing quantum dots comprising a group III-V core according to an embodiment of the present invention, the stirring of step 1 may include step 1-1 of heating the temperature to 110 to 130° C. and then stirring for 25 to 35 minutes. can

In the quantum dot manufacturing method comprising a group III-V core according to an embodiment of the present invention, step 1 is after step 1-1, heating the temperature to 170 to 190° C., and then stirring for 5 to 15 minutes -2 may be included.

In the method for manufacturing a quantum dot including a group III-V core according to an embodiment of the present invention, the group V element of the group V precursor of the second step may be phosphorus (P).

In the method for manufacturing a quantum dot including a group III-V core according to an embodiment of the present invention, the group V precursor of the second step is a phosphorus (P) precursor, including tris(dimethylamino)phosphine. can do.

In the quantum dot manufacturing method comprising a group III-V core according to an embodiment of the present invention, the second step may include a step 2-1 of stirring at 170 to 190° C. for 25 to 35 minutes after adding the group V precursor. can

After step 2 in the method for manufacturing quantum dots including a group III-V core according to an embodiment of the present invention, sulfur (S) in the solvent represented by Formula 1 and the compound containing the grown group III-V core 3 steps of adding and stirring the precursor; and a fourth step of adding and stirring a zinc (Zn) precursor to the solution of step 3 to form a first ZnS shell on the group III-V core.

In the method for manufacturing quantum dots including a group III-V core according to an embodiment of the present invention, the sulfur (S) precursor in step 3 may be tris(octylphosphine)sulfide.

In the quantum dot manufacturing method comprising a group III-V core according to an embodiment of the present invention, the zinc (Zn) precursor in the 4th step is a zinc-stearate (Zn(stearate) ₂ ) solution in which 1-octadecine is dissolved in a solvent. can be

Before adding the sulfur (S) precursor in step 3 in the method for manufacturing a quantum dot comprising a group III-V core according to an embodiment of the present invention, the solvent represented by Formula 1 and the grown group III-V core It may include the step of maintaining the compound containing the at 170 to 190 ℃ for 15 to 25 minutes.

In the method for manufacturing a quantum dot including a group III-V core according to an embodiment of the present invention, step 3 includes a step 3-1 of stirring at 170 to 190° C. for 55 to 65 minutes after adding the sulfur (S) precursor can do.

In the quantum dot manufacturing method comprising a III-V core according to an embodiment of the present invention, step 3 is 3-2 step of stirring the temperature at 180 to 200° C. for 110 to 130 minutes after step 3-1. may include

In the method for manufacturing a quantum dot including a group III-V core according to an embodiment of the present invention, step 4-1 includes adding the zinc (Zn) precursor and stirring at 200 to 230° C. for 140 to 160 minutes. may include

In the quantum dot manufacturing method comprising a group III-V core according to an embodiment of the present invention, step 4 is after step 4-1, after adding a sulfur (S) precursor, at 220 to 240° C. for 170 to 190 minutes. may include 4-2 steps of stirring while

In the quantum dot manufacturing method including a III-V core according to an embodiment of the present invention, step 4 is after step 4-2, after adding the zinc (Zn) precursor, heating to 240 to 260° C. , may include 4-3 steps of stirring for 200 to 220 minutes.

After step 4 in the quantum dot manufacturing method comprising a group III-V core according to an embodiment of the present invention, the solvent represented by Formula 1 and the compound containing the group III-V core on which the first ZnS shell is formed 5 step of adding and stirring the sulfur (S) precursor; and step 6 of adding and stirring the zinc (Zn) precursor to the solution of step 5 to form a second ZnS shell.

Before adding the sulfur (S) precursor in step 5 in the method for manufacturing a quantum dot including a group III-V core according to an embodiment of the present invention, the solvent represented by Formula 1 and the first ZnS shell are formed maintaining the temperature of the compound comprising the group III-V core at 170 to 190° C. for 15 to 25 minutes.

In the quantum dot manufacturing method comprising a group III-V core according to an embodiment of the present invention, step 5 is 5- which is stirred at a temperature of 180 to 200 ° C. for 90 to 130 minutes after adding the sulfur (S) precursor. It may include step 1.

In the method for manufacturing quantum dots including a group III-V core according to an embodiment of the present invention, step 6 is 6-1 in which the zinc (Zn) precursor is added and then stirred at a temperature of 200 to 220° C. for 110 to 130 minutes. may include steps.

In the quantum dot manufacturing method comprising a III-V core according to an embodiment of the present invention, step 6 is after the step 6-1, after adding the sulfur (S) precursor, the temperature is increased to 140 at 220 to 240° C. It may include a step 6-2 of stirring for 160 minutes.

In the method for manufacturing a quantum dot including a group III-V core according to an embodiment of the present invention, step 6 is after step 6-2, after adding a zinc (Zn) precursor, at 240 to 260° C. for 170 to 190 minutes. It may include 6-3 steps of stirring during the

Precipitating a compound including the grown group III-V core after the second step in the method for manufacturing a quantum dot comprising a group III-V core according to an embodiment of the present invention; precipitating a compound including a group III-V core on which the first ZnS shell is formed after step 4; Alternatively, the method may further include precipitating a compound including a group III-V core in which the second ZnS shell is formed on the first ZnS shell after step 5.

Each step of precipitating each compound in the quantum dot manufacturing method comprising a III-V core according to an embodiment of the present invention lowers the temperature to 20 to 35 °C, and then evaporates the solvent represented by the first formula It may include the step of

Each of the steps of precipitating each compound in the method for manufacturing quantum dots including a III-V core according to an embodiment of the present invention may include a step of recrystallization from alcohol.

It is manufactured by the manufacturing method including the group III-V core according to an embodiment of the present invention, and emits light in a visible light wavelength band.

A quantum dot including a III-V core according to an embodiment of the present invention may have a photoluminescence quantum yield (PLQY) of 50% or more in an organic solvent.

A quantum dot including a group III-V core according to an embodiment of the present invention has a cubic crystal structure, and when measured by X-ray diffraction analysis (XRD) with the CuKα radiation = 1.5406 Å wavelength It may have peaks at (110), (200), (220), (311), and (222).

The quantum dot manufacturing method according to an embodiment of the present invention produces a quantum dot including a group III-V core having almost no defects, uniform size and shape, and excellent luminous efficiency even at a high temperature process.

In addition, since the method for producing quantum dots according to an embodiment of the present invention can be performed using only one solvent in one reactor, it is possible to mass-produce quantum dots including group III-V cores simply and economically. .

In addition, the solvent used in the manufacturing process of quantum dots according to an embodiment of the present invention is eco-friendly, does not involve side reactions while having essential chelating properties in quantum dots including group III-V cores, and includes group III-V cores It has good dispersion and can be completely removed from the ligand region after the process. In addition, multiple chelate coordination is possible, so that several types of precursors can be maintained in a constant arrangement at the same time, and it is possible to differentiate the binding of the precursors differently.

1 illustrates a manufacturing process of quantum dots according to an embodiment of the present invention.
2 is a chelate structure by a solvent according to an embodiment of the present invention.
Figure 3 illustrates the chelate bond of a solvent according to an embodiment of the present invention.
4 illustrates a manufacturing process of quantum dots including an InP core according to an embodiment of the present invention.
5 illustrates a manufacturing process of quantum dots including an InP core having a first ZnS shell formed thereon according to an embodiment of the present invention.
6 illustrates a process for manufacturing a quantum dot including an InP core on which a first ZnS shell and a second ZnS shell are formed according to an embodiment of the present invention.
7 is a graph showing measurement results of absorption and emission spectra of quantum dots including an InP core having a first ZnS shell formed thereon according to an embodiment of the present invention.
8 is a graph showing measurement results of absorption and emission spectra of quantum dots including an InP core having a first ZnS shell and a second ZnS shell formed according to an embodiment of the present invention.
9 is a transmission electron microscope (TEM) image of a quantum dot including an InP core having a first ZnS shell formed thereon according to an embodiment of the present invention.
10 is a transmission electron microscope (TEM) image of a quantum dot including an InP core on which a first ZnS shell and a second ZnS shell are formed according to an embodiment of the present invention.
11 is a graph by X-ray diffraction analysis (XRD) of a quantum dot including an InP core with a ZnS shell formed according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail through examples. These examples are only for illustrating the present invention, and therefore, the scope of the present invention is not to be construed as being limited by these examples.

As used herein, an expression such as “comprising” is understood as an open-ended term that includes the possibility of including other embodiments, unless specifically stated otherwise in the phrase or sentence in which the expression is included. should be

As used herein, “preferred” and “preferably” refer to embodiments of the invention that may provide certain advantages under certain circumstances. However, other embodiments may also be desirable, under the same or other circumstances. Additionally, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the invention.

Unlike quantum dots having a group II-IV core, such as CdSe, a quantum dot having a group III-V core is difficult to manufacture. Since the group III-V core is more unstable than the group II-IV core such as CdSe, a continuous process for continuously forming the core and the shell is essential.

In addition, it is essential to use a solvent having a chelating effect, unlike the group II-IV core. More specifically, since In the case of In is +3, since +2 in the case of In is much more Lewis acidic than the Cd element, a much more stable intermediate with a base that forms a "chelate-coordination" such as 'glyme' to facilitate synthesis. Referring to FIG. 2 , in the case of 'tetraglyme', a stable intermediate is formed as a structure in which In + 3 is pentavalent to a cation. In addition, in the case of FIG. 3 , the glyme solvent having a different structure forms a stable intermediate by forming a chelate bond with the In + 3 cation.

In addition, especially in the case of In, it requires a difficult condition not to be mixed with a solvent. In addition, since quantum dots including group III-V cores are manufactured by high-temperature pyrolysis, the solvent used should not participate in the pyrolysis process, and should be easily removed after growth of the InP core. Therefore, it is essential to use a solvent specialized for preparing quantum dots including group III-V cores.

In the process of manufacturing a quantum dot including a group III-V core according to an embodiment of the present invention, a group III-V core that is difficult to prepare a uniform and almost defect-free core by using the glyme solvent represented by the following Chemical Formula 1 To enable mass production of quantum dots containing In addition, since the glyme solvent does not accompany side reactions while having a chelating property, it is possible to prepare quantum dots including group III-V cores having few defects. In addition, in order to increase the luminous efficiency, the ZnS shell can be manufactured by stacking multiple layers, so that the process at high temperature is simplified, and the ZnS shell that is laminated can be effectively protected. In addition, since the group III-V element has better dispersion than other elements, it can be used as a particularly optimized solvent when preparing quantum dots including a group III-V core.

A quantum dot manufacturing method comprising a group III-V core according to an embodiment of the present invention comprises: a first step of adding and stirring a compound containing a group III precursor and zinc (Zn) to a solvent represented by the following formula (1); and a second step of growing a group III-V core by adding and stirring a group V precursor to the stirred solution.

[Formula 1]

(In Formula 1, R1 and R2 are the same as or not identical to each other, and an alkyl group having 1 to 5 carbon atoms, and n is an integer of 1 to 10)

In the method for manufacturing a quantum dot including a group III-V core according to an embodiment of the present invention, in the solvent represented by Formula 1, R1 and R2 may be a methyl (methyl) group. When R1 and R2 are methyl groups, it is named as Ethylene Glycol Dimethyl Ether (EGME).

Referring to FIGS. 2 and 3 , the glyme solvent represented by Chemical Formula 1 may form a chelate bond with an In ion, which is a group III element. Unlike mono-ether systems, mono-, di-, tri-, tetra-glyme structures are used to form multiple chelate coordination bonds with Group III elements such as In. This allows several kinds of precursors to be maintained in a precursor state in a constant arrangement at the same time. It is thus possible to differentiate the binding of the precursors differently.

In addition, the glyme solvent is a compound in the form of a saturated acyclic polyether, which is less volatile and less toxic than conventional organic solvents, and thus is an environmentally friendly solvent. These glyme compounds have both hydrophilic and hydrophobic properties, and in particular, by having hydrophilic properties on both carbon alkyl chains, they can form complexes with ions in thermal and chemical stability. In addition, unlike the mono-ether system, by effectively chelating a group III element, it is possible to prevent the core elements from aggregating with each other.

In addition, since the solvent represented by Formula 1 has two carbon chains between two oxygen atoms, it is possible to form a chelate coordination bond while maintaining the most optimal distance to the group III element.

In addition, in the high-temperature pyrolysis process used as a method for manufacturing a quantum dot including a III-V core and a ZnS shell, the solvent does not participate in the thermal decomposition process, and can be easily removed after the group III-V core is grown.

In addition, since Group III elements have strong Lewis acidity, the oxygen atoms of the glyme solvent also act as a regenerative ligand to prevent decomposition in advance in the process before and after synthesis. In addition, it is useful for washing excess ligands after preparing QDs with a group III-V core-shell structure in the future.

The solvent represented by Formula 1 according to an embodiment of the present invention is monoglyme (n=1), diglyme (n=2), triglyme (n=3), tetraglyme ( n=4) and the like.

In the method for manufacturing a quantum dot including a group III-V core according to an embodiment of the present invention, the group III element of the group III precursor of the first step may be indium (In), but is not particularly limited thereto.

In the quantum dot manufacturing method comprising a group III-V core according to an embodiment of the present invention, the group III precursor of the first step is an indium (In) precursor, In ₂ O ₃ , In ₂ S ₃ , InF ₃ , InCl ₃ , InBr ₃ , InI ₃ , In(CH ₃ CO ₂ ) ₃ , In(OH) ₃ , In(NO ₃ ) ₃ , In(OH) ₃ , In(CN) ₃ , In(ClO ₃ ) ₃ , In(PO ₄ ) and mixtures thereof, but is not particularly limited thereto.

In the quantum dot manufacturing method comprising a group III-V core according to an embodiment of the present invention, the compound containing zinc (Zn) is ZnF ₂ , ZnCl ₂ , ZnBr ₂ , ZnI ₂ , Zn(CH ₃ CO ₂ ) ₂ , Zn(OH) ₂ , Zn(NO ₃ ) ₂ , Zn(SO ₄ ), Zn(CN) ₂ , Zn(ClO ₃ ) ₂ , Zn ₃ (PO ₄ ) ₂ , and mixtures thereof However, it is not particularly limited thereto.

In the quantum dot manufacturing method including a group III-V core according to an embodiment of the present invention, when the group III element of the group III precursor in step 1 is indium (In), the mixing molar ratio of indium (In) and zinc (Zn) is 1:4 to 1:20, 1:8 to 1:20, 1:12 to 1:20, 1:16 to 1:20, 1:4 to 1:16, 1:4 to 1:12, or It may be 1:4 to 1:8.

In the method for manufacturing a quantum dot including a group III-V core according to an embodiment of the present invention, the group V element of the group V precursor of the second step may be phosphorus (P), but is not particularly limited thereto.

In the method for manufacturing a quantum dot including a group III-V core according to an embodiment of the present invention, the group V precursor of the second step is a phosphorus (P) precursor, including tris(dimethylamino)phosphine. However, it is not particularly limited thereto.

When the group V element is phosphorus (P), In ^{3 +} reacts with EGME to form [In(EGME) ₃ ] ³⁺ , and the formed [In(EGME) ₃ ] ³⁺ molecule-molecular bond proceeds (Fig. 2). When tris(dimethylamino)phosphine, that is, P(Me ₂ N) ₃ is added thereto, the reaction may proceed to a step of forming InP by reacting with the previously formed [In(EGME) ₃ ] ³⁺ .

As described above, the method for producing quantum dots according to an embodiment of the present invention is easy because it is possible to prepare quantum dots of the final 'core @ shell @ shell' multi-structure while putting all the reactants in one reaction vessel and gradually raising the temperature. The scale can be increased, so it can be easily applied to mass production in the industrial sense.

In addition, as described above, the quantum dots of the 'core @ shell @ shell' multi-structure can avoid aggregation of particles, so high-efficiency light emission can be expected, and the size of the quantum dot of the core-shell @ shell 'multi-structure' by controlling the core-shell formation time It is possible to selectively generate light in a wide visible ray wavelength band. Therefore, it is possible to manufacture a high-efficiency light emitting device by utilizing these characteristics.

In the method for manufacturing a quantum dot including a group III-V core according to an embodiment of the present invention, step 1 may further add and stir oleylamine.

In the method for producing quantum dots comprising a group III-V core according to an embodiment of the present invention, the stirring of step 1 may include step 1-1 of heating the temperature to 110 to 130° C. and then stirring for 25 to 35 minutes. can

In the quantum dot manufacturing method comprising a group III-V core according to an embodiment of the present invention, step 1 is after step 1-1, heating the temperature to 170 to 190° C., and then stirring for 5 to 15 minutes -2 may be included.

In the quantum dot manufacturing method comprising a group III-V core according to an embodiment of the present invention, the second step may include a step 2-1 of stirring at 170 to 190° C. for 25 to 35 minutes after adding the group V precursor. can

After step 2 in the method for manufacturing quantum dots including a group III-V core according to an embodiment of the present invention, sulfur (S) in the solvent represented by Formula 1 and the compound containing the grown group III-V core 3 steps of adding and stirring the precursor; and a fourth step of adding and stirring a zinc (Zn) precursor to the solution of step 3 to form a first ZnS shell on the group III-V core.

A quantum dot material including a III-V core, such as InP, has a problem in that a photoluminescence quantum yield (PLQY) is very low. The low quantum yield is due to the defect structure of the core, and in order to minimize this, process conditions completely excluding oxygen or moisture are required.

A ZnS shell is formed on the outer layer of the core as a post-process to compensate for the defect structure created during the manufacturing process. In particular, the ZnS shell is best suited for the InP core. The band gap of ZnS is 2.26 eV, and the threshold energy of the valence band is 3.61 eV, which is because the lattice mismatch with the InP core is less than 8%. However, it is necessary to remove oxygen and moisture in order to manufacture quantum dots of InP core and ZnS shell structures. Conventionally, a number of organic solvents and a complex multi-step process were required to prepare a quantum dot of a core-shell structure including a group III-V core. In the present invention, a glyme solvent such as an EGME solvent is used in one reactor. Since quantum dots having an InP-ZnS shell structure can be synthesized only with the present solvent, the problem of contact with oxygen and moisture can be minimized.

In the method for manufacturing quantum dots including a group III-V core according to an embodiment of the present invention, the sulfur (S) precursor in the three steps may be tris(octylphosphine)sulfide, but is not particularly limited thereto.

In the quantum dot manufacturing method comprising a group III-V core according to an embodiment of the present invention, the zinc (Zn) precursor in the 4th step is a zinc-stearate (Zn(stearate) ₂ ) solution in which 1-octadecine is dissolved in a solvent. may be, but is not particularly limited thereto.

Before adding the sulfur (S) precursor in step 3 in the method for manufacturing a quantum dot comprising a group III-V core according to an embodiment of the present invention, the solvent represented by Formula 1 and the grown group III-V core It may include the step of maintaining the compound containing the at 170 to 190 ℃ for 15 to 25 minutes.

In the method for manufacturing a quantum dot comprising a group III-V core according to an embodiment of the present invention, step 3 includes a step 3-1 of stirring at 170 to 190° C. for 55 to 65 minutes after adding the sulfur (S) precursor can do.

In the quantum dot manufacturing method comprising a III-V core according to an embodiment of the present invention, step 3 is 3-2 step of stirring the temperature at 180 to 200° C. for 110 to 130 minutes after step 3-1. may include

In the method for manufacturing a quantum dot including a group III-V core according to an embodiment of the present invention, step 4-1 includes adding the zinc (Zn) precursor and stirring at 200 to 230° C. for 140 to 160 minutes. may include

In the quantum dot manufacturing method comprising a group III-V core according to an embodiment of the present invention, step 4 is after step 4-1, after adding a sulfur (S) precursor, at 220 to 240° C. for 170 to 190 minutes. It may include a 4-2 step of stirring during the

In the quantum dot manufacturing method including a III-V core according to an embodiment of the present invention, step 4 is after step 4-2, after adding the zinc (Zn) precursor, heating to 240 to 260° C. , may include 4-3 steps of stirring for 200 to 220 minutes.

After step 4 in the quantum dot manufacturing method comprising a group III-V core according to an embodiment of the present invention, the solvent represented by Formula 1 and the compound containing the group III-V core on which the first ZnS shell is formed 5 step of adding and stirring the sulfur (S) precursor; and step 6 of adding and stirring the zinc (Zn) precursor to the solution of step 5 to form a second ZnS shell.

Before adding the sulfur (S) precursor in step 5 in the method for manufacturing a quantum dot including a group III-V core according to an embodiment of the present invention, the solvent represented by Formula 1 and the first ZnS shell are formed maintaining the temperature of the compound comprising the group III-V core at 170 to 190° C. for 15 to 25 minutes.

In the quantum dot manufacturing method comprising a group III-V core according to an embodiment of the present invention, step 5 is 5- which is stirred at a temperature of 180 to 200 ° C. for 90 to 130 minutes after adding the sulfur (S) precursor. It may include step 1.

In the method for manufacturing quantum dots including a group III-V core according to an embodiment of the present invention, step 6 is 6-1 in which the zinc (Zn) precursor is added and then stirred at a temperature of 200 to 220° C. for 110 to 130 minutes. may include steps.

In the quantum dot manufacturing method comprising a III-V core according to an embodiment of the present invention, step 6 is after the step 6-1, after adding the sulfur (S) precursor, the temperature is increased to 140 at 220 to 240° C. It may include a step 6-2 of stirring for 160 minutes.

In the method for manufacturing a quantum dot including a group III-V core according to an embodiment of the present invention, step 6 is after step 6-2, after adding a zinc (Zn) precursor, at 240 to 260° C. for 170 to 190 minutes. It may include 6-3 steps of stirring during the

The ZnS shell may have a single layer or a multilayer structure of two or more layers. When the ZnS shell is formed, the thickness of the shell layer may vary depending on the reaction temperature and time, and thus the effect may also vary.

Precipitating a compound including the grown group III-V core after the second step in the method for manufacturing a quantum dot comprising a group III-V core according to an embodiment of the present invention; precipitating a compound including a group III-V core on which the first ZnS shell is formed after step 4; Alternatively, the method may further include precipitating a compound including a group III-V core in which the second ZnS shell is formed on the first ZnS shell after step 5.

Each step of precipitating each of the compounds in the method for producing quantum dots comprising a III-V core according to an embodiment of the present invention lowers the temperature to 20 to 35 °C, and then evaporates the solvent represented by the first formula It may include the step of

Each step of precipitating each of the compounds in the method for manufacturing quantum dots including a III-V core according to an embodiment of the present invention may include a step of recrystallizing from alcohol.

1, 4 to 6, performing a reaction to sequentially form ZnS shells in the core InP, or to sequentially form the shells as soon as the core InP is formed by a one-pot reaction in one reactor It is possible.

A quantum dot including a group III-V core according to an embodiment of the present invention is manufactured by the above manufacturing method, and emits light in a wavelength band of visible light.

Quantum dots including group III-V cores according to an embodiment of the present invention have a photoluminescence quantum yield (PLQY) of 45% or more, more preferably 55% or more, more preferably 70% or more in an organic solvent. can

A quantum dot including a III-V core according to an embodiment of the present invention has a cubic crystal structure, and when measured by X-ray diffraction (XRD) with a wavelength of CuKα radiation = 1.5406 Å It may have peaks at (110), (200), (220), (311), and (222) (FIG. 10).

<General Experiment>

Indium trichloride (InCl ₃ , Alfa Aeser), zinc chloride (ZnCl ₂ , Sigma-Aldrich), tetra-Glyme (Sigma-Aldrich), sulfur powder (90%, Sigma-Aldrich), tris(dimethylamino) ) phosphine (Sigma-Aldrich), trioctylphosphine sulfide (TOP-S, Sigma-Aldrich), zinc-stearate (industrial use), 1-octadecene (ODE, 90%, Sigma-Aldrich), olylamine ( OA, 70%, Sigma-Aldrich) and hexanes (99%, Sigma-Aldrich) were used. In addition, a Schlenk reaction method was applied using a vacuum box, a high vacuum line, and the like. Other reagents were supplied by Aldrich, and the vacuum box was manufactured by Yujeon Co., Ltd. and other high-vacuum glassware was used.

<Example>

InP core synthesis

First, indium trichloride (0.45 mmol) and zinc chloride (300 mg, 2,2 mmol) were dissolved in tetraglyme (5 mL), and then this solution was added dropwise to olylamine (5.0 mL, 15 mmol). The reaction was stirred at 120° C. for 30 minutes under a vacuum atmosphere. Then, argon gas was injected and heated to 180°C. After 10 min, tris(dimethylamino)phosphine (0.45 mL, 1.6 mmol) was quickly injected into the solution. In this process, an InP core was formed, and the InP core formation was completed within 30 minutes. After the reaction was completed, the temperature of the solution was lowered to room temperature, and the InP core was recrystallized in a solid state with ethanol (50 mL).

InP@ZnS core-shell synthesis

The InP core was dissolved in tetraglyme (5 mL) and stirred at 180° C. for 20 minutes. To this solution was added trioctylphosphinesulfide liquid (2.2 M, 1 mL). The mixture was stirred at the same temperature of 180° C. for an additional 60 minutes. The temperature was then heated from 180° C. to 200° C. and stirred for an additional 120 minutes. To this solution, a solution of zinc-stearate (1 g) in 1-octadecene (4 mL) was slowly added dropwise. The temperature was then heated from 200° C. to 220° C. and stirred for an additional 150 minutes. To this solution was slowly added trioctylphosphinesulfide liquid (2.2 M, 0.7 mL). The temperature was then heated from 220° C. to 240° C. and stirred for an additional 180 minutes. To this solution, a solution of zinc-stearate (0.5 g) in 1-octadecene (2 mL) was slowly added dropwise. The temperature was then heated from 240° C. to 260° C. and stirred for an additional 210 minutes. In this process, an InP@ZnS core-shell is formed. After the reaction was completed, the temperature of the solution was lowered to room temperature, and the InP@ZnS core-shell was recrystallized in a solid state with ethanol (50 mL).

InP@ZnS@ZnS core-shell-shell synthesis

The InP@ZnS core-shell was dissolved in tetraglyme (5 mL) and stirred at 180° C. for 20 minutes. To this solution was added trioctylphosphinesulfide liquid (2.2 M, 1 mL). At this temperature, 180° C., the mixture was stirred for an additional 30 minutes. The temperature was then heated from 180° C. to 200° C. and stirred for an additional 90 minutes. To this solution, a solution of zinc-stearate (1 g) in 1-octadecene (4 mL) was slowly added dropwise. The temperature was then heated from 200° C. to 220° C. and stirred for an additional 120 minutes. To this solution was slowly added trioctylphosphinesulfide liquid (2.2 M, 0.7 mL). The temperature was then heated from 220° C. to 240° C. and stirred for an additional 150 minutes. To this solution, a solution of zinc-stearate (0.5 g) in 1-octadecene (2 mL) was slowly added dropwise. The temperature was then heated from 240° C. to 260° C. and stirred for an additional 180 minutes. In this process, InP@ZnS@ZnS core-shell-shell was formed. After the reaction was completed, the temperature of the solution was lowered to room temperature, and the InP@ZnS@ZnS core-shell-shell was recrystallized in a solid state with ethanol (50 mL).

<Experimental example>

After the quantum dots were prepared according to the above example, they were analyzed by dissolving them in hexane as an organic solvent.

7 and 8 show absorption and emission spectra of InP quantum dots having a core @ shell and a core @ shell @ shell multi-structure prepared according to the above embodiment. According to this, it can be confirmed that a core@shell and a core@shell@shell structure including an InP core stably exhibiting excellent light emitting characteristics in the 620 nm wavelength band, respectively, were manufactured.

In addition, TEM images of InP quantum dots of core @ shell and core @ shell @ shell multi-structures prepared according to the above examples are shown in FIGS. 9 and 10 . According to this, it can be confirmed that the spherical InP quantum dots are manufactured.

In addition, the XRD measurement results of the core-shell and core-shell-shell multi-structured InP quantum dots prepared according to the above example are shown in FIG. 11 . According to this, it can be confirmed that the manufactured quantum dots have cubic phase crystallinity. This means that the InP quantum dots prepared according to an embodiment of the present invention can be usefully used as a high-efficiency light-emitting material. In addition, the InP quantum dots prepared according to the embodiment of the present invention showed a property of maintaining the shape of the weanal even during sonication.

Meanwhile, the light emission quantum yield of the quantum dot materials prepared according to the above example was calculated using Equation 1 below.

Equation 1: Q = Q _R (OD _R /OD)(I/I _R )( n _R ² / n ² )

In Equation 1, Q, OD, I, and n represent quantum yield, optical density, integrated light intensity, and refractive index of a solvent, respectively, and R means a reference sample.

The emission quantum yields of the core @ shell and core @ shell @ shell multi-structured InP quantum dots determined by this method were 0.49 and 0.80, respectively.

Claims (34)

1 step of adding and stirring a compound containing a Group III precursor and zinc (Zn) to a solvent represented by the following Chemical Formula 1; and
A second step of growing a group III-V core by adding and stirring a group V precursor to the stirred solution;
The group III element of the group III precursor in step 1 is indium (In),
A method for manufacturing quantum dots comprising a III-V core.
[Formula 1]

(In Formula 1, R1 and R2 are the same as or not identical to each other, an alkyl group having 1 to 5 carbon atoms, and n is an integer of 3 to 10)
The method of claim 1,
In the solvent represented by Formula 1, R1 and R2 are methyl (methyl) groups,
A method for manufacturing quantum dots comprising a III-V core.
The method of claim 1,
The solvent represented by Formula 1 in step 1 is selected from the group consisting of triglyme (n=3), tetraglyme (n=4) and mixtures thereof,
A method for manufacturing quantum dots comprising a III-V core.
delete The method of claim 1,
The group III precursor of step 1 is an indium (In) precursor, In ₂ O ₃ , In ₂ S ₃ , InF ₃ , InCl ₃ , InBr ₃ , InI ₃ , In(CH ₃ CO ₂ ) ₃ , In(OH) ₃ , In(NO ₃ ) ₃ , In(OH) ₃ , In(CN) ₃ , In(ClO ₃ ) ₃ , In(PO ₄ ) and mixtures thereof,
A method for manufacturing quantum dots comprising a III-V core.
The method of claim 1,
The compound containing zinc (Zn) is ZnF ₂ , ZnCl ₂ , ZnBr ₂ , ZnI ₂ , Zn(CH ₃ CO ₂ ) ₂ , Zn(OH) ₂ , Zn(NO ₃ ) ₂ , Zn(SO ₄ ), selected from the group consisting of Zn(CN) ₂ , Zn(ClO ₃ ) ₂ , Zn ₃ (PO ₄ ) ₂ , and mixtures thereof,
A method for manufacturing quantum dots comprising a III-V core.
delete The method of claim 1,
The first step is to further add and stir oleylamine,
A method for manufacturing a quantum dot comprising a III-V core.
The method of claim 1,
The stirring of step 1 includes step 1-1 of heating the temperature to 110 to 130° C. and then stirring for 25 to 35 minutes,
A method for manufacturing quantum dots comprising a III-V core.
10. The method of claim 9,
In step 1, after step 1-1, heating the temperature to 170 to 190° C., and then stirring for 5 to 15 minutes, including 1-2 steps,
A method for manufacturing a quantum dot comprising a III-V core.
The method of claim 1,
The group V element of the group V precursor of step 2 is phosphorus (P),
A method for manufacturing quantum dots comprising a III-V core.
The method of claim 1,
The group V precursor of the second step is a phosphorus (P) precursor, including tris (dimethylamino) phosphine (tris (dimethylamino) phosphine),
A method for manufacturing quantum dots comprising a III-V core.
The method of claim 1,
Step 2 includes step 2-1 of stirring at 170 to 190° C. for 25 to 35 minutes after adding the group V precursor,
A method for manufacturing quantum dots comprising a III-V core.
The method of claim 1,
After step 2 above,
A third step of adding and stirring a sulfur (S) precursor to the compound including the solvent represented by Formula 1 and the grown group III-V core; and
Further comprising; adding and stirring a zinc (Zn) precursor to the solution of step 3 to form a first ZnS shell on the group III-V core;
A method for manufacturing a quantum dot comprising a III-V core.
15. The method of claim 14,
The sulfur (S) precursor of step 3 is tris (octylphosphine) sulfide,
A method for manufacturing quantum dots comprising a III-V core.
15. The method of claim 14,
The zinc (Zn) precursor of step 4 is a solution in which zinc-stearate (Zn (stearate) ₂ ) is dissolved in 1-octadecine solvent,
A method for manufacturing quantum dots comprising a III-V core.
15. The method of claim 14,
Before adding the sulfur (S) precursor in step 3, maintaining the compound including the solvent represented by Formula 1 and the grown group III-V core at 170 to 190° C. for 15 to 25 minutes containing,
A method for manufacturing quantum dots comprising a III-V core.
15. The method of claim 14,
Step 3 includes a step 3-1 of stirring at 170 to 190° C. for 55 to 65 minutes after adding the sulfur (S) precursor,
A method for manufacturing quantum dots comprising a III-V core.
19. The method of claim 18,
Step 3 includes a 3-2 step of stirring the temperature at 180 to 200° C. for 110 to 130 minutes after the 3-1 step,
A method for manufacturing quantum dots comprising a III-V core.
15. The method of claim 14,
Step 4 includes step 4-1 of adding the zinc (Zn) precursor and stirring at 200 to 230°C for 140 to 160 minutes,
A method for manufacturing quantum dots comprising a III-V core.
21. The method of claim 20,
Step 4 comprises a 4-2 step of stirring at 220 to 240° C. for 170 to 190 minutes after adding a sulfur (S) precursor after step 4-1,
A method for manufacturing quantum dots comprising a III-V core.
22. The method of claim 21,
In step 4, after step 4-2, adding the zinc (Zn) precursor, heating to 240 to 260° C., and then stirring for 200 to 220 minutes, including step 4-3,
A method for manufacturing a quantum dot comprising a III-V core.
15. The method of claim 14,
After step 4 above,
a fifth step of adding and stirring the sulfur (S) precursor to the compound including the solvent represented by Formula 1 and the group III-V core on which the first ZnS shell is formed; and
Further comprising; adding and stirring the zinc (Zn) precursor to the solution of step 5 to form a second ZnS shell;
A method for manufacturing quantum dots comprising a III-V core.
24. The method of claim 23,
Before adding the sulfur (S) precursor in step 5, the temperature of the compound including the solvent represented by Chemical Formula 1 and the group III-V core on which the first ZnS shell is formed is 15 to 170° C. to 190° C. holding for 25 minutes,
A method for manufacturing a quantum dot comprising a III-V core.
24. The method of claim 23,
Step 5 includes step 5-1 of stirring at a temperature of 180 to 200° C. for 90 to 130 minutes after adding the sulfur (S) precursor,
A method for manufacturing quantum dots comprising a III-V core.
24. The method of claim 23,
Step 6 includes adding the zinc (Zn) precursor, followed by stirring at a temperature of 200 to 220° C. for 110 to 130 minutes, 6-1.
A method for manufacturing quantum dots comprising a III-V core.
27. The method of claim 26,
Step 6 includes a 6-2 step of stirring the temperature at 220 to 240° C. for 140 to 160 minutes after adding the sulfur (S) precursor after step 6-1,
A method for manufacturing a quantum dot comprising a III-V core.
28. The method of claim 27,
Step 6 includes a step 6-3 of stirring at 240 to 260° C. for 170 to 190 minutes after adding a zinc (Zn) precursor after step 6-2,
A method for manufacturing quantum dots comprising a III-V core.
24. The method of claim 1, 14 or 23,
precipitating a compound including the grown group III-V core after step 2;
precipitating a compound including a group III-V core on which the first ZnS shell is formed after step 4; or
Further comprising the step of precipitating a compound including a group III-V core in which the second ZnS shell is formed on the first ZnS shell after step 5;
A method for manufacturing quantum dots comprising a III-V core.
30. The method of claim 29,
Each step of precipitating each compound comprises a step of evaporating the solvent represented by Formula 1 after lowering the temperature to 20 to 35 °C,
A method for manufacturing a quantum dot comprising a III-V core.
29. The method of claim 28,
Each step of precipitating each compound comprises a step of recrystallization from alcohol,
A method for manufacturing a quantum dot comprising a III-V core.
It is prepared by the manufacturing method of claim 1,
Emitting light in the visible wavelength band,
Quantum dots comprising III-V cores.
33. The method of claim 32,
Photoluminescence Quantum Yield (PLQY) of 45% or more in an organic solvent,
Quantum dots comprising III-V cores.
33. The method of claim 32,
The crystal structure is cubic,
CuKα radiation = having peaks at (110), (200), (220), (311), and (222) measured by X-ray diffraction (XRD) with a wavelength of 1.5406 Å
Quantum dots comprising III-V cores.

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