KR101518315B1 - preparing method of multishell semiconductor nano particles using seed - Google Patents

Abstract

The present invention relates to a method for manufacturing multi-layered semiconductor nanoparticles using a seed. Specifically, the invention relates to the method for manufacturing multi-layered semiconductor nanoparticles having the size of 7-9 mm and a peak in the light-emitting wavelength range of 400-700 mm regardless of changes in the size of the particle by adopting a seed formed of spherical nanoparticles including carbon. The method for manufacturing multi-layered semiconductor nanoparticles using a seed according to an embodiment of this invention comprises the steps of: (a) reacting a compound, which contains spherical nanoparticles including carbon among organic solvents, with a compound containing IIB group element to form a seed formed of spherical nanoparticles including carbon, a first shell including a compound comprising IIB group element and VIA group element and semiconductor nanoparticles having a structure of a seed or the first shell; (b) reacting a compound IIB element among organic solvents with a compound containing VIA group element to form a second shell, which includes a compound comprising IIB group element and VIA group element on the surface of the first shell and has a wider ban gap than the first shell; (c) reacting a compound containing IIB group element among organic solvents with a compound containing VIA group element to form a third shell, which includes a compound comprising IIB group element and VIA group element on the surface of the second shell and has a wider bandgap than the second shell; and (d) reacting a compound containing IIB group element among organic solvents with a compound containing VIA group element to form a fourth shell, which includes a compound comprising IIB group element and VIA group element on the surface of the third shell and has a wider bandgap than the third shell.

Description

[0001] The present invention relates to a method for preparing a semiconductor nanoparticle,

More particularly, the present invention relates to a method for producing a semiconductor nanoparticle having a multilayer structure using seeds, and more particularly, to a method for manufacturing a semiconductor nanoparticle having a grain size of 7 to 9 nm by introducing a seed made of spherical nanoparticles containing carbon as a seed And has a peak within an emission wavelength range of 400 to 700 nm irrespective of a change in particle size, and does not decrease the luminescence characteristics of the semiconductor nanoparticles.

In general, the chemical and physical properties of solid crystals are independent of the size of the crystals. However, when the size of a solid crystal becomes a region of several nanometers, its size may be a variable that influences the chemical and physical properties of the crystal. Research on the formation of semiconductor nanocrystals (nanoclusters) or quantum dots among such nanotechnologies has been actively conducted worldwide.

Quantum dots having a size of several nanometers exhibit a unique behavior of a quantum effect, and are known to be applicable to a semiconductor structure for creating a high-efficiency light emitting device, and an emission mark of a molecule in a living body.

Group IIB-VIA Group Compounds Having Various Compositions The study of quantum dots and group IIA and group VA compound quantum dots can be achieved by varying the semiconductor structure such as the size and surface of semiconductor crystals in the nanometer range, The basic principle is to change the gap.

Among these IIB group-VIA group compound quantum dots and Group IIIA and VA Group compound quantum dots, much attention has been focused on quantum dots having a core / shell structure. Core / shell quantum dots have been developed to change the crystal surface and to maintain or improve the chemical and physical properties of the quantum dots, such as the luminescence properties, in various surrounding environments.

The quantum dots of such a core / shell structure are generally quantum dots having a shell formed on the core surface with a bandgap wider than the bandgap of the core. The shell of the core surface has a lower energy sharing band than the core, And has a band gap due to a conduction band of energy higher than that of the band.

As the core / shell quantum dots, zinc selenide (ZnSe) / zinc sulfide (ZnS) (Korean Patent Registration No. 10-0376403) and the like are known.

These various Group IIB-VIA group compound quantum dots and Group IIIA and Group VA compound quantum dots are different in luminescence range, luminescence efficiency, chemical stability, and thermal stability depending on their composition, and thus the application range of each quantum dot And application methods are limited. The quantum dots of the conventional core / shell structure do not satisfy high luminescence efficiency, high luminescence sharpness and chemical stability at the same time. Particularly, the emission intensity reduction phenomenon due to light and heat is very apparent, .

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a semiconductor nanoparticle having a particle size of 7 to 9 nm by introducing a seed made of spherical nanoparticles containing carbon into a multi-layered semiconductor nanoparticle, The present invention relates to a method for producing excellent semiconductor nanoparticles in which a peak is present within an emission wavelength range of 400 to 700 nm and emission characteristics are not reduced.

According to an aspect of the present invention, there is provided a method for preparing a semiconductor nanoparticle comprising the steps of: (a) mixing a spherical nanoparticle-containing compound containing carbon in an organic solvent with a compound containing a Group IIB element, And a first shell containing a compound consisting of a group consisting of spherical nanoparticles containing carbon and a group IIB element and a group VIA element to form semiconductor nanoparticles of a seed / ; (b) reacting a Group IIB element-containing compound and a Group VIA element-containing compound in an organic solvent to form a compound comprising a Group IIB element and a Group VIA element on the surface of the first shell; Forming a second shell having a large bandgap; (c) reacting a Group IIB element-containing compound and a Group VIA element-containing compound in an organic solvent to form a compound comprising a group IIB element and a Group VIA element on the surface of the second shell; Forming a third shell having a large bandgap; And (d) a step of reacting a Group IIB element-containing compound and a Group VIA element-containing compound in an organic solvent to form a compound comprising a Group IIB element and a Group VIA element on the surface of the third shell, And forming a fourth shell having a larger bandgap.

According to another embodiment of the present invention, there is provided a method for preparing a multi-layered semiconductor nanoparticle comprising: (a) a step of preparing a spherical nanoparticle-containing compound containing carbon in an organic solvent, a compound containing a Group IIB element and a compound containing a Group VIA element And a second compound obtained by reacting the first compound obtained by reacting the first compound and the Group A element-containing compound with the Group A element-containing compound, and a second compound obtained by reacting the first compound and the Group A element- Forming a seed / first shell structure semiconductor nanoparticle of a first shell comprising a mixture of a first compound and a second compound; (b) reacting a Group IIIA element-containing compound with a Group V element-containing compound in an organic solvent to form a compound comprising a group IIIA element and a Group V element on the surface of the first shell, Forming a second shell having a large bandgap; (c) reacting a compound containing a group IIIA element and a group-A element-containing compound in an organic solvent to form a compound comprising a group IIIA element and a group VI element on the surface of the second shell; Forming a third shell having a large bandgap; And (d) a step of reacting a Group IIB element-containing compound and a Group VIA element-containing compound in an organic solvent to form a compound comprising a Group IIB element and a Group VIA element on the surface of the third shell, And forming a fourth shell having a larger bandgap.

The semiconductor nanoparticles of the multi-layer structure manufactured by the production method of the present invention have a particle size of 7-9 nm by introducing a seed composed of spherical nanoparticles containing carbon and have a particle size of 400-700 nm There is an effect that a peak is present within the emission wavelength range of the emission spectrum and the emission characteristic is not reduced.

In particular, since the semiconductor nanoparticles of the present invention have peaks within the emission wavelength range of 400 to 700 nm irrespective of the change in particle size, there is no need to adjust the particle size to change the emission color, So that the manufacturing process is simplified.

1 is a graph showing changes in emission wavelength of semiconductor nanoparticles synthesized up to the seed / first shell according to Examples 1 to 7.
FIG. 2 is a graph showing a change in emission wavelength of a thin film prepared using semiconductor nanoparticles synthesized up to the seed / fourth shell according to Examples 8 to 12. FIG.
3, 4, and 5 are TEM photographs of the semiconductor nanoparticles produced in Examples 1, 2, and 3, respectively.
FIG. 6 is a graph showing a change in emission wavelength of a thin film during LED operation for 13 days after the thin film is formed on the surface of 5050 LED with the semiconductor nanoparticles prepared in Example 1. FIG.
FIG. 7 is a graph showing a change in emission wavelength of a thin film during LED operation for 13 days after a thin film is formed on the surface of a 5050 LED using the semiconductor nanoparticles prepared in Comparative Example 1. FIG.
8 is a graph showing a change in the color coordinates of a thin film when the blue light emitting diode is operated after the thin film is formed of the semiconductor nanoparticle of Example 1 on the surface of the blue light emitting diode. 9 is a graph showing changes in the wavelength of light emitted from the thin film of the blue light emitting diode after the thin film of the semiconductor nanoparticle of Example 1 is formed on the surface of the blue light emitting diode.
10 is a graph showing a change in the color coordinates of a thin film when the blue light emitting diode is operated after a thin film is formed of the semiconductor nanoparticle of Comparative Example 1 on the surface of the blue light emitting diode.
11 is a graph showing changes in the emission wavelength of a thin film of blue light emitting diode after forming a thin film of semiconductor nanoparticles of Comparative Example 1 on the surface of the blue light emitting diode.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving it, will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

A method for manufacturing semiconductor nanoparticles according to a preferred embodiment of the present invention will be described in detail as follows.

The method for producing semiconductor nanoparticles of the present invention comprises sequentially forming a seed-first shell forming step, a second shell forming step, a third shell forming step and a fourth shell forming step, and more specifically, (a) Containing compound and a Group VIA element-containing compound to form a seed consisting of spherical nanoparticles containing carbon and a compound composed of a group IIB element and a Group VIA element, by reacting a spherical nanoparticle- Forming a semiconductor nanoparticle of a seed / first shell structure of a first shell comprising a first seed and a second seed; (b) reacting a Group IIB element-containing compound and a Group VIA element-containing compound in an organic solvent to form a compound comprising a Group IIB element and a Group VIA element on the surface of the first shell; Forming a second shell having a large bandgap; (c) reacting a Group IIB element-containing compound and a Group VIA element-containing compound in an organic solvent to form a compound comprising a group IIB element and a Group VIA element on the surface of the second shell; Forming a third shell having a large bandgap; And (d) a step of reacting a Group IIB element-containing compound and a Group VIA element-containing compound in an organic solvent to form a compound comprising a Group IIB element and a Group VIA element on the surface of the third shell, And forming a fourth shell having a larger bandgap.

According to another embodiment of the present invention, there is provided a method for preparing a multi-layered semiconductor nanoparticle comprising: (a) a step of preparing a spherical nanoparticle-containing compound containing carbon in an organic solvent, a compound containing a Group IIB element and a compound containing a Group VIA element And a second compound obtained by reacting the first compound obtained by reacting the first compound and the Group A element-containing compound with the Group A element-containing compound, and a second compound obtained by reacting the first compound and the Group A element- Forming a seed / first shell structure semiconductor nanoparticle of a first shell comprising a mixture of a first compound and a second compound; (b) reacting a Group IIIA element-containing compound with a Group V element-containing compound in an organic solvent to form a compound comprising a group IIIA element and a Group V element on the surface of the first shell, Forming a second shell having a large bandgap; (c) reacting a compound containing a group IIIA element and a group-A element-containing compound in an organic solvent to form a compound comprising a group IIIA element and a group VI element on the surface of the second shell; Forming a third shell having a large bandgap; And (d) a step of reacting a Group IIB element-containing compound and a Group VIA element-containing compound in an organic solvent to form a compound comprising a Group IIB element and a Group VIA element on the surface of the third shell, And forming a fourth shell having a larger bandgap.

The thus obtained semiconductor nanoparticles of the present invention have a structure including a seed, a first shell, a second shell, a third shell, and a fourth shell sequentially and have a particle size of 7 to 9 nm.

In the method for producing semiconductor nanoparticles of the present invention, the Group IIB element-containing compound may include cadmium oxide, zinc acetate, cadmium acetate, cadmium chloride, zinc chloride, zinc oxide, zinc stearate, mercury chloride, mercury oxide, The compound containing the Group VIA element is preferably a sulfur powder, a selenium powder, a tellurium powder, a polonium powder, an octanethiol or a combination thereof. The compound containing the Group VIA element is preferably used in combination with trioctylphosphine, Tributylphosphine, trioctylamine or the like is more preferably used.

The Group IIIA element-containing compound may be one or more selected from the group consisting of an In-containing compound, a Ga-containing compound, an Al-containing compound and a Ti-containing compound. Or more. Specifically, the Group IIIA element-containing compound may be at least one selected from the group consisting of indium acetate, indium chloride, indium hydroxide, indium oxide, gallium chloride, aluminum chloride, aluminum chlorohydrate, aluminum hydroxide, aluminum nitrate, aluminum oxide, It is preferable that the Group V element-containing compound is at least one member selected from the group consisting of trioctylphosphine oxide, trioctylphosphine, triphenylphosphine, tris (dimethyl (meth) acrylate) Amino) phosphine, tris (trimethylsilyl) phosphine, acenic trichloride, or a combination thereof.

In the method for producing semiconductor nanoparticles of the present invention, the organic solvent is preferably toluene, hexadecylamine, trioctylamine, octadecene, octadecane, trioctylphosphine, oleylamine, or a combination thereof . In addition, in the method for producing semiconductor nanoparticles according to the present invention, it is preferable that the organic solvent further contains an unsaturated fatty acid in addition to an organic solvent. Examples of the unsaturated fatty acid include oleic acid, stearic acid, myristic acid, lauric acid, There may be used acid, elaidic acid, eicosanoic acid, heneicosanoic acid, tricosanoic acid, docosanoic acid, tetracosanoic acid, hexacosanoic acid, octacosanoic acid heptacosanoic acid or cis-13- have.

In the method for producing semiconductor nanoparticles of the present invention, the reaction temperature in each step is about 110 to 350 ° C, specifically 280 to 350 ° C in step (a), 280 to 320 ° C in step (b) And 300 to 320 ° C in the step (d).

In the method for producing semiconductor nanoparticles according to the present invention, the spherical nanoparticle-containing compound containing carbon in step (a) may be selected from among C60, C70, C76, C84, C80, C84, C180, C240, Containing compound is at least one selected from a Cd-containing compound or a Zn-containing compound, and the VIA group-containing compound is at least one selected from a Se-containing compound or an S-containing compound. Specifically, the Cd-containing compound or the Zn-containing compound may be CdO or ZnO, respectively, and the Se-containing compound or S-containing compound may be Se powder or 1-dodecanethiol dissolved in trioctylphosphine. At this time, the spherical nanoparticle-containing compound, the Group IIB element-containing compound, and the Group VIA element-containing compound all belong to the non-implantation method in which the reaction is carried out under uniform conditions.

When a mixture of the group IIIA element-containing compound and the group VA element-containing compound is used, the group IIIA element-containing compound may be at least one selected from an In-containing compound or a Ga-containing compound, an Al- The Group VA element-containing compound may be at least one selected from the P-containing compound and the As-containing compound.

In the method for producing semiconductor nanoparticles according to the present invention, the Group IIB element compound in the step (b) is a Cd-containing compound, specifically, CdO, and the Group VIA element compound is an S-containing compound, Thiol may be dissolved in trioctylamine or S powder may be dissolved in trioctylphosphine.

When a mixture of the group IIIA element-containing compound and the group VA element-containing compound is used, the group IIIA element-containing compound may be at least one selected from an In-containing compound or a Ga-containing compound, an Al- The Group VA element-containing compound may be at least one selected from the P-containing compound and the As-containing compound.

The reactant after the step (b) includes semiconductor nanoparticles having a multilayered structure having a seed / first shell / second shell structure, wherein the reactants are cooled to room temperature and then reacted with acetone, methanol, butanol or toluene, Hexane, chloroform, or a dispersion solvent comprising a combination of two or more thereof, at a specific concentration, and is preferably used in step (c).

At this time, the concentration of the semiconductor nanoparticles dispersed in the dispersion solvent can be represented by the absorbance value at a specific wavelength (for example, 430 nm, 605 nm, etc.), and the absorbance value of the semiconductor nanoparticles dispersed in the dispersion solvent is about 0.05 - 0.5. Also, the thickness of the third shell and the fourth shell formed in the subsequent step are adjusted in consideration of the thickness.

In the method for producing semiconductor nanoparticles according to the present invention, the molar ratio of the heterogeneous Group IIB element-containing compound, that is, the Cd-containing compound and the Zn-containing compound in the step (c) may be 1: 5 to 10, 1: 3 to 4, more specifically 1: 3.5. Here, the Cd-containing compound may be CdO, and the Zn-containing compound may be zinc acetate or ZnO. The Group VIA element-containing compound may be an S-containing compound, and specifically, octane thiol may be dissolved in trioctylamine or S powder may be dissolved in trioctylphosphine.

When a mixture of the group IIIA element-containing compound and the group VA element-containing compound is used, the group IIIA element-containing compound may be at least one selected from an In-containing compound or a Ga-containing compound, an Al- The Group VA element-containing compound may be at least one selected from the P-containing compound and the As-containing compound.

In the method for producing semiconductor nanoparticles according to the present invention, the group IIB element-containing compound in the step (d) may be a Zn-containing compound, and the group 16 element-containing compound may be an S-containing compound. Specifically, the Zn-containing compound may be zinc acetate or ZnO, and the S-containing compound may be one obtained by dissolving octanethiol in trioctylamine or S-powder in trioctylphosphine.

At this time, the Zn-containing compound reacts in step (c), and the S-containing compound is injected according to the molar ratio of Zn, and the reaction proceeds.

The semiconductor nanoparticles of the present invention thus produced are provided as semiconductor nanoparticle solutions (more precisely, semiconductor nanoparticle sols) dispersed in toluene, hexene, chloroform, or a dispersion solvent comprising a combination of two or more of them. A light emitting device can be manufactured by applying a particle solution to the surface of a light emitting element to form a thin film.

More specifically, a composition for forming a thin film in which a semiconductor nanoparticle solution of the present invention and a curing agent are mixed is coated on the surface of a light emitting diode and cured at a temperature of about 120 to 150 ° C for about 1 to 2 hours to form a semiconductor nanoparticle LED (The curing temperature and the curing time may vary depending on the characteristics of the curing agent). The LED manufactured from the semiconductor nanoparticles of the present invention does not decrease the luminescence characteristics even during long operation and has a peak within the emission wavelength range of 400 to 700 nm irrespective of the change of the particle size. There is no need to adjust the particle size, so that a further process of forming a shell is unnecessary, and the manufacturing process is simplified.

The semiconductor nanoparticles according to the preferred embodiments of the present invention will now be described in detail.

The multi-layered semiconductor nanoparticles of the present invention include a seed consisting of spherical nanoparticles containing carbon; And a plurality of shells sequentially surrounding the surface of the seed, wherein the plurality of shells comprises a semiconductor compound consisting of Group IIB elements and Group VIA elements; Or a semiconductor compound consisting of Group IIIA elements and Group VA elements; Or mixtures thereof; Or CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS , HgZnSeTe, HgZnSTe, GaNP, GaNAs, GaPAs, AlNP, AlNAs, AlPAs, InNP, InNAs, InPAs, GaAlNP, GaAlNAs, GaAlPAs, GaInNP, GaInNAs, GaInPAs, InAlNP, InAlNAs, InAlPAs, SnS, CuInS, CuZnS, CuSnS, CuSnSe , CuSnGaS, and CuSnGaSe, and has a larger bandgap as the distance from the seed increases.

The band gap of each layer of the multi-layered semiconductor nanoparticles of the present invention becomes larger from the seed to the outermost shell, and thereby the quantum mechanical wave function of electrons and holes generated in the inside of the semiconductor nanoparticles can be better maintained .

According to the present invention, semiconductor nanoparticles of a seed / multishell structure in which the bandgap of each layer becomes larger toward the outermost shell from the seed can be designed by adjusting the kind and composition ratio of the components constituting the seed and each shell.

The seeds in the multi-layered semiconductor nanoparticles of the present invention are composed of spherical nanoparticles containing carbon. The carbon of the spherical nanoparticles containing carbon is 60 to 540. Specifically, the seed of the present invention is a fullerene which is selected from among C60, C70, C76, C84, C80, C84, C180, C240 and C540 desirable.

Spherical nanoparticles comprising carbon, which can be used as the seeds of the present invention, refer to carbon-based compounds in closed basket form, which can be referred to as fullerenes. Since the spherical nanoparticles containing carbon which can be used as the seed of the present invention have an n-orbital resonance structure, light of almost all wavelengths in the visible light region can be absorbed. Therefore, the wavelength of the light absorbed by the electrons can be changed by the reaction of the seed / one shell in the multi-layered semiconductor nanoparticle of the present invention.

This is completely different from the quantum dots of a conventional core / shell structure using a principle of showing a selective peak within the emission wavelength range by changing the particle size. The multi-layered semiconductor nanoparticle of the present invention has the above- The completed semiconductor nanoparticles can have a quantum efficiency of 70% for blue, 80% for green, and 90% or more for red, while realizing the semiconductor nanoparticles of the completed multilayer structure in almost the same size.

In the present invention, the number of moles of spherical nanoparticles containing carbon is preferably 0.001 to 0.0005 mol. If it is out of the above range, the luminous efficiency in the visible light region is lowered.

In the multilayered semiconductor nanoparticle of the present invention, a plurality of shells are formed on the surface of the seed, the plurality of shells include a first shell formed on a surface of the seed; A second shell formed on a surface of the first shell, the second shell having a larger bandgap than the first shell; A third shell formed on the surface of the second shell, the third shell having a larger bandgap than the second shell; And a fourth shell formed on the surface of the third shell, the fourth shell having a larger bandgap than the third shell.

More specifically, the plurality of shells comprise a semiconductor compound consisting of Group IIB elements and Group VIA elements; Or a semiconductor compound consisting of Group IIIA elements and Group VA elements; Or mixtures thereof; Or CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS , HgZnSeTe, HgZnSTe, GaNP, GaNAs, GaPAs, AlNP, AlNAs, AlPAs, InNP, InNAs, InPAs, GaAlNP, GaAlNAs, GaAlPAs, GaInNP, GaInNAs, GaInPAs, InAlNP, InAlNAs, InAlPAs, SnS, CuInS, CuZnS, CuSnS, CuSnSe , CuSnGaS, CuSnGaSe, and has a larger bandgap away from the seed.

In the multilayered semiconductor nanoparticles of the present invention, the first shell may be a compound composed of at least one kind selected from the group IIB elements, at least one combination selected from the group VIA elements, or a semiconductor compound composed of the group IIB elements and the group VIA elements, Element and a group of semiconductor compounds consisting of Group VA elements.

In the multi-layered semiconductor nanoparticle of the present invention, the first shell is formed on the surface of the seed, and by controlling the molar ratio between the elements constituting the first shell, the characteristics of the seed absorbing light of almost all wavelengths in the visible light region And can be suitably used. That is, by controlling the molar ratio between the atoms constituting the first shell, the emission color can be adjusted as desired so that the semiconductor nanoparticles of the seed / first shell can emit light peaks within the range of 400 to 560 nm at almost the same particle size have.

When the first shell is a compound composed of at least one kind selected from Group IIB elements and at least one kind selected from the group consisting of a combination of at least one element selected from Group VIA elements, specifically, in the case of a CdZnSeS compound, the molar ratio of Cd: Zn is 1: 0.5-10 And the molar ratio of Se: S based on the sum of the molar ratios of CdZn may be 1: 0.5 to 10. For example, when the molar ratio of Cd: Zn is 1:10, the emission peak is about 400 to 430 nm. When the ratio of Cd: Zn is 2: 1, the emission peak is about 540 to 560 nm. The emission color can be controlled as desired.

On the other hand, when the first shell is a mixture of the semiconductor compound consisting of the Group IIB element and the Group VIA element and the semiconductor compound composed of the Group IIIA element and the Group A element, specifically, in the case of the S (InZn) P compound, May be 1: 0.5 to 10, and the molar ratio of P: S may be 1: 0.5 to 10 based on the sum of mole ratios of InZn. For example, when the molar ratio of In: Zn is 1: 10, the emission peak is about 400 to 430 nm, and when the mole ratio of In: Zn is 2: 1, the emission peak appears at about 540 to 560 nm. The emission color can be controlled as desired.

In the multilayered semiconductor nanoparticle of the present invention, the second shell is formed on the surface of the first shell, and includes a compound made of a group IIB element and a group VIA element or a semiconductor compound made of a group IIIA element and a group VA element, And has a band gap larger than the band gap of the first shell.

In the multi-layered semiconductor nanoparticle of the present invention, the third shell is formed on the surface of the second shell, and includes a semiconductor compound composed of Group IIB elements and Group VIA elements or a semiconductor compound composed of Group IIIA elements and Group VA elements , And has a band gap larger than the band gap of the second shell.

In the multilayered semiconductor nanoparticle of the present invention, the fourth shell is formed on the surface of the third shell, and includes a compound consisting of Group IIB elements and Group VIA elements, and has a band gap larger than the band gap of the third shell Respectively.

The multi-layered semiconductor nanoparticles according to the present invention have a particle size of about 5 to 9 nm, preferably about 7 to 9 nm, and more preferably about 7.5 to 8.5 nm, in consideration of light- nm. The quantum dot of the present invention has a particle size of 7.5-8.5 nm and has a peak within the emission wavelength range of 400-700 nm irrespective of particle size change. It is necessary to control the particle size to change the emission color There is an effect that a further process of forming a shell is unnecessary and the manufacturing process is simplified.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments of the present invention and comparative examples thereof. The following examples are intended to clearly illustrate the present invention and are not intended to limit the scope of protection of the present invention.

Example  One : C60  The seed / CdZnSeS  The first shell / CdS  The second shell / CdS Wow ZnS Lt; RTI ID = 0.0 > shell / ZnS  Fabrication of multi-layered semiconductor nanoparticles of the fourth shell structure

(1) Example 1-1: Synthesis of C60 seed / CdZnSeS first shell

1) Preparation of first stock solution: C60 content

In a 50 ml flask, 0.001 to 0.0005 mol of C60 was added to 5 ml of toluene and dispersed by stirring for 1 hour. Then, 3 ml of oleic acid was added, and then 10 ml of 1-octadecene was added, followed by stirring for 2 hours. Then, the temperature was elevated to 110 ° C. for 30 minutes in a vacuum state to remove toluene. After that, the temperature was raised to 310 ° C. in a nitrogen atmosphere to obtain a clear solution containing C60 and then cooled to room temperature to obtain a first stock solution containing C60 .

2) Preparation of second stock solution: Containing Cd precursor and Zn precursor

(0.001 mol) of CdO, 6 ml of oleic acid and 6 ml of octadecene were charged and vigorously stirred while nitrogen gas was being filled to prepare a Cd precursor solution.

0.095 g (0.001 mol) of ZnO, 6 ml of oleic acid and 6 ml of octadecene were charged and vigorously stirred in a nitrogen gas filled state to prepare a Zn precursor solution.

The prepared Cd precursor solution (4.8 ml) and Zn precursor solution (4.8 ml) were mixed to obtain a second stock solution having a molar ratio of Cd and Zn of 1: 1.

3) Synthesis of seed / first shell

A first stock solution containing a second stock solution having a molar concentration of Cd and Zn of 0.1 mol / L and a molar ratio of Cd: Zn of 1: 1 and 0.0005 mol of C60 was placed in a 50 ml flask, and a Se stock powder 8.4 and 0.015 ml of 1-dodecanethiol (C12-SH) were heated to 300 DEG C and heated for 30 minutes to obtain semiconductor nanoparticles of the C60 seed / CdZnSeS first shell structure. At this time, the mole ratio of Se: S was 1: 5.

(2) Example 1-2: Synthesis of second shell composed of CdS

4 ml (0.0003 mol) of a cadmium stock solution and 70 μl (0.4 mol) of n-octanethiol were dissolved in 3 ml of trioctylamine. The solution was subjected to a CdZnSeS Was dropped into the reactor in which the C60 seed having the first shell formed was present. Thereafter, the reaction was carried out at 280 to 320 ° C for about 17 minutes to form a second shell made of CdS on the surface of the CdZnSeS first shell formed on the surface of the C60 seed. The semiconductor nanoparticles formed up to the second shell were washed with butanol and dispersed in toluene to prepare a semiconductor nanoparticle solution having an absorbance of 0.1 at about 515 to 525 nm , and 6 ml of the solution was prepared in advance. Absorbance values in semiconductor nanoparticle solutions indirectly indicate the concentration of semiconductor nanoparticles.

(3) Example 1-3: Synthesis of third shell composed of CdS and ZnS

0.4 g (0.0025 mol) of zinc acetate, 0.08 g (0.0006 mol) of cadmium oxide, 2.5 ml (7.8 mmol) of oleic acid and 20 ml of trioctylamine were placed in a separate reactor (equipped with a syringe, a condenser and a thermometer) The temperature was raised to about 110 ° C in the state of being depressurized and then heated to about 320 ° C in a state filled with nitrogen gas and stirred to obtain a clear solution containing a complex of cadmium and oleic acid and a complex of zinc and oleic acid. Thereafter, the temperature of the solution in the reactor was adjusted to about 320 ° C, and 6 ml of the semiconductor nanoparticle solution having the second shell prepared in Example 1-2 was quickly injected. Immediately, 560 μl (3.2 mmol) Octylamine was dropwise added to the reactor at a rate of about 0.5 ml / min by using a metering pump. And then reacted at 320 ° C for about 48 minutes to form a third shell of CdS and ZnS on the surface of the second shell made of CdS. The molar ratio of CdS to ZnS in the third shell was about 1: 3. Here, the Zn ²⁺ ions remaining as unreacted materials were used for the synthesis of the fourth shell.

(4) Example 1-4: Synthesis of fourth shell composed of ZnS

The n-octanethiol was injected once again with a dosing pump (0.5 ml / min) between 280 and 320 ° C according to the molar ratio of Zn remaining in the third shell, and reacted for 2 hours. After the reaction was completed, the solution was slowly cooled to room temperature, washed, and stored in toluene to complete the solution containing the semiconductor nanoparticles of the present invention.

Example  2: C60  The seed / CdZnSeS  The first shell / CdS  The second shell / CdS Wow ZnS Lt; RTI ID = 0.0 > shell / ZnS  Fabrication of multi-layered semiconductor nanoparticles of the fourth shell structure

In Example 1-1, a second stock solution having a molar ratio of Cd: Zn of 1:10 was prepared, the molar ratio of Se: S was 1: 9,

In Example 1-3, instead of octanethiol, 0.1 g of S powder was dispersed in 3 ml of trioctylphosphine, which was used as a sulfur precursor solution,

The other conditions were the same as those of Example 1 to prepare semiconductor nanoparticles having a multilayer structure.

Example  3: C60  The seed / CdZnSeS  The first shell / CdS  The second shell / CdS Wow ZnS Lt; RTI ID = 0.0 > shell / ZnS  Fabrication of multi-layered semiconductor nanoparticles of the fourth shell structure

In Example 1-1, a second stock solution having a molar ratio of Cd: Zn of 2: 1 was prepared, and the molar ratio of Se: S was 9: 1,

The other conditions were the same as those of Example 1 to prepare semiconductor nanoparticles having a multilayer structure.

Example  4: C60  The seed / CdZnSeS  The first shell / CdS  The second shell / CdS Wow ZnS Lt; RTI ID = 0.0 > shell / ZnS  Fabrication of multi-layered semiconductor nanoparticles of the fourth shell structure

A second stock solution having a molar ratio of Cd: Zn of 1: 5 was prepared in Example 1-1, and the molar ratio of Se: S was 1: 5 to 6,

The other conditions were the same as those of Example 1 to prepare semiconductor nanoparticles having a multilayer structure.

Example  5: C60  The seed / CdZnSeS  The first shell / CdS  The second shell / CdS Wow ZnS Lt; RTI ID = 0.0 > shell / ZnS  Fabrication of multi-layered semiconductor nanoparticles of the fourth shell structure

A second stock solution having a molar ratio of Cd: Zn of 1: 3 was prepared in Example 1-1, and the molar ratio of Se: S was 1: 4 to 5,

The other conditions were the same as those of Example 1 to prepare semiconductor nanoparticles having a multilayer structure.

Example  6: C60  The seed / CdZnSeS  The first shell / CdS  The second shell / CdS Wow ZnS Lt; RTI ID = 0.0 > shell / ZnS  Fabrication of multi-layered semiconductor nanoparticles of the fourth shell structure

In Example 1-1, a second stock solution having a molar ratio of Cd: Zn of 1: 2 was prepared, and the molar ratio of Se: S was 1: 3 to 4,

The other conditions were the same as those of Example 1 to prepare semiconductor nanoparticles having a multilayer structure.

Example  7: C60  The seed / CdZnSeS  The first shell / CdS  The second shell / CdS Wow ZnS Lt; RTI ID = 0.0 > shell / ZnS  Fabrication of multi-layered semiconductor nanoparticles of the fourth shell structure

A second stock solution having a molar ratio of Cd: Zn of 1: 4 was prepared in Example 1-1, and the molar ratio of Se: S was 1: 3.5 to 4.5,

The other conditions were the same as those of Example 1 to prepare semiconductor nanoparticles having a multilayer structure.

Comparative Example  One: CdSe core/ CdS  The first shell / ZnS  Fabrication of multi-layered semiconductor nanoparticles of second shell structure

(1) Comparative Example 1-1: Synthesis of CdSe Core

0.103 g (0.8 mmol) of cadmium oxide, 1 ml of oleic acid and 20 ml of trioctylamine were placed in a reactor equipped with a syringe, a condenser and a thermometer (J type thermocouple). The solution was vigorously stirred while being filled with nitrogen gas, . Then, the temperature of the solution in the reactor was adjusted to about 320 DEG C, and 100 mu l of 2M TOPSe solution (0.2 mmol based on selenium) was rapidly injected. Thereafter, CdSe was grown at 320 DEG C for about 10 minutes to synthesize a core made of CdSe. After the synthesis of the CdSe core is completed, about 0.6 mmol of cadmium is present in the solution in the form of a complex with oleic acid.

(2) Comparative Example 1-2: Synthesis of first shell composed of CdS

As soon as the synthesis of the CdSe core of Comparative Example 1-1 was completed, 105 μl (0.6 mmol) of n-octanethiol was dissolved in 3 ml of trioctylamine. The CdSe core was present at a rate of about 1 ml / min using a metering pump Lt; / RTI > Thereafter, the reaction was carried out at 320 DEG C for about 27 minutes to form a first shell of CdS on the surface of the CdSe core.

(3) Comparative Example 1-3: Synthesis of second shell made of ZnS

0.55 g (3.0 mmol) of zinc acetate, 1.5 ml of oleic acid and 10 ml of trioctylamine were placed in a separate reactor (equipped with a syringe, a condenser and a thermometer), and the temperature was raised to about 110 DEG C while being reduced to a vacuum. The solution was heated to about 320 DEG C while being filled with gas and stirred to obtain a clear solution containing the complex.

As soon as the synthesis of the first shell composed of CdS of Comparative Example 1-2 was completed, a clear solution containing the complex of cadmium and oleic acid was added to a reactor in which the quantum dots having the structure of CdSe core / CdS first shell existed in the reactor of about 2 ml / min. < / RTI > At the end of the injection, 560 μl (3.2 mmol) of n-octanethiol dissolved in 3 ml of trioctylamine was added dropwise into the reactor at a rate of about 2 ml / min using a metering pump. And then reacted at 320 ° C for about 60 minutes to form a second shell made of ZnS on the surface of the first shell made of CdS.

Subsequently, the reaction mixture was slowly cooled to room temperature, added with acetone and butanol, and then centrifuged to wash red light emitting quantum dots having the structure of CdSe core / CdS first shell / ZnS second shell. Then, red light emitting semiconductor nanoparticles having a structure of CdSe core / CdS first shell / ZnS second shell were dispersed in toluene to prepare semiconductor nanoparticle solution.

evaluation

One. Evaluation of luminescence characteristics

The semiconductor nanoparticles synthesized up to the seed / first shell according to Examples 1 to 7 were each dispersed in toluene to prepare a semiconductor nanoparticle solution. The concentration of the semiconductor nanoparticle solution was adjusted so that the absorbance at about 535 nm became 0.1, Fig. 1 shows the change in the emission wavelength with the use of the intensity measuring device.

.

1, the semiconductor nanoparticles of the present invention having a seed / first shell structure have a wavelength range of 400 to 560 nm by changing the molar ratio of the Group 12 elements constituting the first shell, that is, Cd and Zn. It can be seen that various emission peaks can be designed in the light emitting layer. It was also found that semiconductor nanoparticles having an emission peak in a wavelength range of 560 nm or more can be obtained by further synthesizing a shell.

2. Particle size evaluation

TEM photographs were taken of the semiconductor nanoparticles of the seed / first shell / second shell / third shell / fourth shell structure prepared in Examples 1, 2 and 3, and the results are shown in FIGS. 2, 3 and 4 Respectively. As a result, it was confirmed that they exhibited luminescence in different wavelength ranges with the same particle size. As a result, it was confirmed that the semiconductor nanoparticles of the present invention had peaks within the emission wavelength range of 400 to 700 nm irrespective of the change in particle size, so that it was not necessary to adjust the particle size to change the emission color.

3. Quantum efficiency test of semiconductor nanoparticles

The semiconductor nanoparticles of Examples 1, 2 and 3 of the present invention were repeatedly produced three times each, and their quantum efficiency, absorbance, half width and the like were measured, and the results are shown in Tables 1, 2 and 3, respectively.

Quantum yield (%) Abs Peak wave
length Peak count Peak FWHM Peak wave
length Peak count Peak FWHM standard - - 439.74 37757.8 5.36 458.52 74.17 50.94 Example
1 (1) 86.70% 0.675 439.74 23550.01 5.36 519.18 1142.71 37.79 Example
1 (2) 86.20% 0.675 439.74 23513.23 5.37 521.42 1135.11 37.76 Example
1 (3) 85.90% 0.675 439.74 23519.71 5.36 521.42 1141.34 37.65

Quantum yield (%) Abs Peak wave
length Peak count Peak FWHM Peak wave
length Peak count Peak FWHM standard - - 359.88 73131.51 5.6 394.59 85.72 103.58 Example
2 (1) 71.70 0.625 359.88 12736.83 5.62 438.24 5648.49 19.88 Example
2 (2) 71.80 0.624 359.88 12827.86 5.6 437.49 8668.26 19.85 Example
2 (3) 71.80 0.624 359.88 12858.58 5.61 437.49 8664.39 19.87

Quantum yield (%) Abs Peak wave
length Peak count Peak FWHM Peak wave
length Peak count Peak FWHM standard - - 480.27 35803.53 5.37 527.4 7.33 125.89 Example
3 (1) 85.50 0.627 480.27 27322.12 5.38 625.64 777.55 32.94 Example
3 (2) 85.80 0.626 480.27 27356.16 5.37 626.38 777.77 33.03 Example
3 (3) 85.80 0.627 480.27 27413.21 5.36 625.64 778.67 33.14

5. 5050 LED Performance test

The thin film was formed on the surface of 5050 LED with the semiconductor nanoparticles prepared in Example 1 and Comparative Example 1, and the change in the wavelength of the thin film was measured during the operation of the LED for 13 days, and the results are shown in FIGS. 5 and 6, respectively .

FIG. 5 shows the case of Example 1, and FIG. 6 shows the case of Comparative Example 1. As can be seen from FIGS. 5 and 6, in the case of the semiconductor nanoparticles of the present invention, .

6. LED  Operation test

The nanoparticle concentration of the green light emitting semiconductor nanoparticle solution prepared in Example 1 and Comparative Example 1 was about After adjusting the absorbance at 535 nm to 0.1, a curing agent (product name: Dow Corning 6630) was added thereto to prepare a composition for forming a thin film. At this time, the content of the curing agent was about 1% by weight based on the total weight of the composition for forming a thin film. The composition for forming a thin film was applied to the surface of a blue light emitting diode and cured at about 130 캜 for 2 hours to form a thin film of red light emitting semiconductor nanoparticles. Then, the blue light emitting diode was operated for 30 to 120 minutes, and the color coordinates of the quantum dot thin film according to the operation time of the blue light emitting diode, the wavelength of the emitted light, and the hue observed by the naked eye were measured.

7 is a graph showing a change in the color coordinates of a thin film when the blue light emitting diode is operated after forming a thin film of the semiconductor nanoparticle of Example 1 on the surface of the blue light emitting diode. FIG. 2 is a graph showing a change in emission wavelength of a thin film when a blue light emitting diode is operated after a thin film is formed with nanoparticles. FIG.

9 is a graph showing a change in the color coordinates of the thin film when the blue light emitting diode is operated after the thin film of the semiconductor nanoparticle of Comparative Example 1 is formed on the surface of the blue light emitting diode. FIG. 2 is a graph showing a change in emission wavelength of a thin film when a blue light emitting diode is operated after a thin film is formed with nanoparticles. FIG.

From the results of FIGS. 8 and 10, the light emission intensity reduction rate after 30 to 120 minutes of operation of the contrast light emitting diode at the initial operation of the light emitting diode was calculated to be about -0.5% for the semiconductor nanoparticle of Example 1, The film formed from the semiconductor nanoparticles of Example 1 was about -27%. As a result, it was confirmed that the semiconductor nanoparticles of the present invention exhibited remarkably reduced light emission intensity due to light and heat, and thus were excellent in light emission characteristics.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. Such changes and modifications are intended to fall within the scope of the present invention unless they depart from the scope of the present invention. Accordingly, the scope of the present invention should be determined by the following claims.

Claims (4)

(a) reacting a spherical nanoparticle-containing compound containing carbon in an organic solvent with a compound containing a Group IIB element and a Group VIA element to form a seed comprising spherical nanoparticles containing carbon and a group IIB element Forming a semiconductor nanoparticle of a seed / first shell structure of a first shell containing a compound consisting of a Group VIA element and a Group VIA element;
(b) reacting a Group IIB element-containing compound and a Group VIA element-containing compound in an organic solvent to form a compound comprising a Group IIB element and a Group VIA element on the surface of the first shell; Forming a second shell having a large bandgap;
(c) reacting a Group IIB element-containing compound and a Group VIA element-containing compound in an organic solvent to form a compound comprising a group IIB element and a Group VIA element on the surface of the second shell; Forming a third shell having a large bandgap; And
(d) reacting a Group IIB element-containing compound and a Group VIA element-containing compound in an organic solvent to form a compound comprising a Group IIB element and a Group VIA element on the surface of the third shell; And forming a fourth shell having a large bandgap.
(METHOD FOR MANUFACTURING SEMICONDUCTOR.
(a) reacting a first compound obtained by reacting a spherical nanoparticle-containing compound containing carbon in an organic solvent with a compound containing a Group IIB element and a Group VIA element, and a Group IIIA element-containing compound and a Group V element- And a first shell containing a mixture of the first compound and the second compound, and a seed / first shell structure of a mixture of the first compound and the second compound, Forming semiconductor nanoparticles;
(b) reacting a Group IIIA element-containing compound with a Group V element-containing compound in an organic solvent to form a compound comprising a group IIIA element and a Group V element on the surface of the first shell, Forming a second shell having a large bandgap;
(c) reacting a compound containing a group IIIA element and a group-A element-containing compound in an organic solvent to form a compound comprising a group IIIA element and a group VI element on the surface of the second shell; Forming a third shell having a large bandgap; And
(d) reacting a Group IIB element-containing compound and a Group VIA element-containing compound in an organic solvent to form a compound comprising a Group IIB element and a Group VIA element on the surface of the third shell; And forming a fourth shell having a large bandgap.
(METHOD FOR MANUFACTURING SEMICONDUCTOR.
3. The method according to claim 1 or 2,
Wherein the spherical nanoparticles containing carbon are fullerenes selected from C60, C70, C76, C84, C80, C84, C180, C240 and C540.
(METHOD FOR MANUFACTURING SEMICONDUCTOR.
3. The method according to claim 1 or 2,
Wherein the multi-layered semiconductor nanoparticles have a particle size of 7 to 9 nm and a peak is present within an emission wavelength range of 400 to 700 nm irrespective of a change in particle size.
(METHOD FOR MANUFACTURING SEMICONDUCTOR.

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