WO2011008064A2

WO2011008064A2 - Particles containing quantum dot and method for producing same

Info

Publication number: WO2011008064A2
Application number: PCT/KR2010/004716
Authority: WO
Inventors: 이윤식; 전봉현; 이혁재; 정흥수; 최평
Original assignee: 서울대학교 산학협력단; 주식회사 나노스퀘어
Priority date: 2009-07-17
Filing date: 2010-07-19
Publication date: 2011-01-20
Also published as: KR101609618B1; WO2011008064A9; WO2011008064A3; KR20150121722A; KR101651798B1; KR20120049273A

Abstract

The present invention relates to particles containing a quantum dot and a method for producing thereof. More particularly, the present invention relates to particles containing a quantum dot which comprises a core particle and at least one quantum dot nanoparticle which is fixed on the surface of the core particle and a method for producing thereof.

Description

Quantum dot-containing particles and methods for preparing the

The present invention relates to quantum dot-containing particles and a method for producing the same. More specifically, the present invention is inorganic or polymeric core particles; And at least one quantum dot nanoparticle bonded to a surface of the core particle, and a quantum dot-containing particle and a method of manufacturing the same.

Recently, nanometer-sized materials are attracting attention as the size of the materials down to nanometers introduces new physical properties that are not seen in bulk, and as these nanomaterials change in size and shape, This is due to the fact that new characteristics change. Changes in physical properties at the nanometer scale are not only due to the so-called 'scale factors' that come from shrinking in size, but also from the more fundamental properties of the material. In other words, the different physical properties of nanomaterials vary according to their causes, suggesting that they do not simply depend on size.

Among these nanomaterials, the quantum dot is a nano-sized semiconductor material, and when it is smaller than a certain size, the quantum dot is more restricted in the electron motion characteristics of the semiconductor material in the bulk state, and thus the quantum limitation in which the emission wavelength is different from the bulk state (quantum confinement) A substance that exhibits an effect. When the quantum dot receives light from an excitation source and reaches an energy excited state, the quantum dot emits energy according to a corresponding energy band gap. Therefore, by adjusting the size of the quantum dot it is possible to adjust the band gap, to obtain energy of various wavelength bands, thereby showing optical, electrical and magnetic properties that are completely different from the original physical properties.

The wavelength of the light emitted by the quantum dots may be selected according to the physical properties of the quantum dots, such as the size of the quantum dots used, the material constituting the nanocrystals. Quantum dots are known to emit light at wavelengths of about 300 nm to 1700 nm (ie, from ultraviolet to near infrared and infrared). Light that emits light using quantum dots mainly includes red, blue, green, and the like, but is not limited thereto. These colors and fluorescence wavelengths are continuously adjustable. That is, the wavelength band emitted by the quantum dots is determined by the size of the core or the size of the core and the cap, and depends on the material constituting the core and the cap.

That is, the wavelength band emitted can be adjusted by configuring one or more of the combination, size, and cap of the quantum dots.

In addition, the brightness of the light emitted by the quantum dot can also be adjusted. For each color, when it has 10 levels of brightness (0 to 9), since the background "0" cannot be identified, it can be classified into 9 codes except this. In general, n brightness levels and m colors can generate (n ^m -1) codes. Quantum dots can absorb a wide or narrow band of energy from the electromagnetic beam and, when excited, emit a detectable electromagnetic beam with a narrow wavelength band. Here, since the narrow wavelength band is 40 nm or less on a FWHM (full width at a half maximum) basis, ideally, quantum dots emitting a plurality of colors can be used simultaneously without overlapping the spectrum.

Quantum dots having these characteristics, combined with nanotechnology that synthesizes and uses them, have been studied in various and wide fields such as electronics, optical communication, biosystems, and new materials.

For example, as an application in electronic technology, Klein et al. Prepared a single electron transistor (SET) from CdSe quantum dots [Klein DL, et al., A single-electron transistor made from a cadmium selenide nanocrystal, Nature 389, pp. .699-701 (1997)], U.S. Pat.No. 5,710,18, discloses one sulfur of dithiol having sulfur, which is covalently bonded to the metal on the surface of a metal such as gold or aluminum. After forming a monolayer by combining with a metal used as a substrate, a method of forming a single layer of quantum dots by forming the other sulfur to be combined with the surface of the compound semiconductor quantum dots has been developed. Subsequently, research is being conducted for application to general electronic products such as flat panel displays, solar cell photosensitizers, and light sources, which are spotlighted as next-generation displays, such as light emitting diodes (LEDs) and white lights.

In particular, starting with the study of measuring the fluorescence emitted from the quantum dots by infiltrating the quantum dots into the cells using quantum dot nanoparticles, the approach to the biotechnology field using nanoparticles has been in the spotlight recently.

Specifically, radioisotopes were initially used as markers in the fields of DNA sequencing, clinical diagnostic assays, etc. There was a problem such as a short half-life. In order to solve this problem, as a nonisotopic detection method in recent years, organic reporter molecules with fluorescence, luminescence, and electron activating properties are combined with enzymes to cause color change. Mainly used [Kricka; Ed., Nonisotopic Probing, Blotting and Sequencing, Academic Press, New York, 1995; Issac, Ed., Protocols for Nucleic Acid Analysis by Nonradioactive Probes, Humana, Totowa, J. J., 1994; Diamandis and Christopoulos, Eds., Immunoassay, Academic Press, New York, 1996]. These non-isotopic systems have solved most of the above-mentioned problems of radioisotope detection, but the use of these materials, so-called photobleaching, dramatically reduces the inherent luminescence properties of quantum dots due to sensitivity and continuous use. In addition to the deterioration of stability due to the occurrence of a problem, there were problems such as narrow excitation region having a wide emission profile, peak overlap in multiple tests, and limitation on the number of labeling substances.

Luminescent semiconductor quantum dots, such as Zn-S capped CdSe, are about 20 times brighter than those of organic dyes such as fluorescent rhodamine and 100 times more stable against photobleaching. In addition, it has a spectral line width that is about 3 times narrower and has a large number of labeling materials, and has been widely used recently.

In the last decades, research on the synthesis and characterization of these quantum dots has been conducted. For example, several studies have enabled the mass production of relatively monodisperse quantum dots with relatively monodisperse properties [Murray et al., J Am. Chem. Soc., 115, 8706-15 (1993); Bowen Katari et al., J Phys. Chem., 98, 4109-17 (1994); Hines et al., J Phys. Chem., 100, 468-71 (1996)], and other studies have characterized the lattice structure of quantum dots [Henglein, Chem. Rev., 89, 1861-73 (1989); Weller et al., Chem, Int. Ed. Engl. 32, 41-53 (1993)], and also a method for manufacturing a quantum dot array (Murray et al., Sceience, 270, 1335-38 (1995)). In particular, II-VI group semiconductors are receiving attention, thereby achieving an unprecedented degree of monodispersity and crystalline order. As a representative method for synthesizing such quantum dots, according to high temperature pyrolysis, Group II in a solvent such as tri-n-octylphoshpine oxide (hereinafter referred to as 'TOPO') at high temperature If the metal precursor and the Group VI chalcogenide precursor are added, the Group II-VI metal chalcogenide (CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe) semiconductor quantum dots can be obtained (Murray (1993), tactical). One document].

In addition, recent studies have demonstrated that the luminescent properties are enhanced by capping the shell having a high band gap on a core particle having a controllable low band gap. For example, by capping a ZnS layer on a CdSe quantum dot to obtain a strong light emission characteristics (35-50% quantum yields) at room temperature, by adjusting the size of the powder, the light emission wavelength can be adjusted from blue to red Techniques for achieving this have been proposed. Moreover, the ZnS capping protects the surface of the core, ensuring good stability of the quantum dots [Dabbousi et al., J Phys. Chem. B 101, 9463-75 (1997).

However, despite these remarkable advances in luminescent quantum dot technology, capped quantum dots are not bioavailable, which means that their surfaces are not hydrophilic and that most nanoparticles, including these quantum dots, are exemplified by Cd, Zn, Co, and others. This is because it is made of heavy metals. Therefore, in order to utilize them as a bio-system, biocompatible treatment and hydrophilicity treatment should be performed on the surface of the synthesized nanoparticles. For example, by introducing inorganic or organic compounds such as silica or polyethyleneglycol, which are known to be harmless to the living body, to the surface of the synthesized nanoparticles, not only can the hydrophilicity of the nanoparticles be increased, but also in vivo. Increasing the circulation time of the research (Suming Nie et al., In vivo Cancer Targeting And Imaging with semiconductor Quantum Dots' Nat. Biotechnol., 2004 (22), 969; Republic of Korea Patent No. 821192].

However, when the quantum dots are capped with a hydrophilic harmless substance such as silica, the quantum dots are encapsulated in the capped material, and thus the size or number of the quantum dots are very difficult to control, the synthesis technique is complicated, and the difficult conditions must be performed. In the process of performing surface modification, the luminous efficiency is rapidly increased due to stabilizers such as polyvinylpyrrolidone (PVP), which is added to convert hydrophobicity of quantum dot nanoparticles to hydrophilicity by TOPO, a hydrophobic material coated on the surface. There was a problem of deterioration. In addition, even when this is applied to electronic devices such as flat panel displays and light sources, the luminous efficiency is low, mass synthesis is difficult and difficult to handle.

The basic object of the present invention is an inorganic or polymeric core particle; And at least one quantum dot nanoparticle bonded to the surface of the core particle.

It is still another object of the present invention to provide a method for preparing quantum dot-containing particles, comprising bonding at least one quantum dot nanoparticle to a core particle in a hydrophilic organic solvent through covalent bonding, ionic bonding or physical adsorption.

As shown in FIG. 1A, the quantum dot-containing particles of the present invention include core particles 100; At least one quantum dot nanoparticle 200 coupled to the surface of the core particle. The number of the quantum dot nanoparticles 200 introduced to the surface of the core particle 100 is preferably 1 to 8,200,000, more preferably 10 to 640,000.

The inorganic core particles may be silica, alumina (Al ₂ O ₃ , AlO ₂ ), titanium dioxide or zinc dioxide. Alternatively, the polymeric core particles may be polystyrene or polymethylmethacrylate. It is preferable that the diameter of the said core particle is 2 micrometers-1,000 micrometers.

The core particles and the quantum dot nanoparticles may be bonded by covalent bonds, ionic bonds or physical adsorption. In this case, the covalent bond may be formed by a functional group including one atom of sulfur, nitrogen or phosphorus bonded to the quantum dot nanoparticle on one side and bonded to the core particle on the other side. The functional group may be a silane group, an amino group, a sulfone group, a carboxy group or a hydroxyl group.

The quantum dot nanoparticles are a single core structure consisting of a II-VI-based semiconductor, a III-V-based semiconductor, or a IV-IV-based semiconductor, or a II-VI-based semiconductor is capped on the single core structure. Core / shell structure. The diameter of the quantum dot nanoparticles is preferably 1 nm to 20 nm.

Here, the quantum dots corresponding to the core of the single core or the core / cap structure may use all the above kinds of semiconductors. For example, the semiconductors of the group II-VI series are periodic tables. At least one group IIB element and at least one group VIB element are bonded to each other. Examples of the group II-VI type semiconductors include CdS, CdSe, CdTe, ZnSe, ZnS, PbS, PbSe, HgS, HgSe, HgTe, CdHgTe, CdSe _x Te _1-x, etc. are mentioned. Examples of the III-V group semiconductors include GaAs, InAs, InP, and the like. Among the semiconductor materials, the II-VI-based semiconductor is most preferably used as the core, and the diameter thereof is 1 nm to 20 nm, more preferably 2 nm to 10 nm.

In addition, in a core / shell structure, a shell refers to a semiconductor quantum dot that forms a coating layer on the surface of a core semiconductor in combination with the core semiconductor quantum dot. By the shell) structure, nanoparticles having higher luminous efficiency than single core structure can be obtained. The shell has a larger band gap than the core semiconductor and serves as a passivation layer to protect the core semiconductor from the outside. As the shell, a II-VI series semiconductor having a high band gap is used. For example, ZnS, CdS or ZnSe may be preferably used. In the combination of core / shell structures using the same, when the core is composed of CdSe or CdS, the shell may use ZnS, and when the core is CdSe, CdS or ZnSe is used as the shell. Various combinations can be used without limitation.

The quantum dot-containing particles of the present invention may further include an inorganic material or a polymer shell covering the quantum dot-containing particles. That is, as shown in Figure 1b, the quantum dot-containing particles of the present invention may include an inorganic material or a polymer shell (300) surrounding the core particle 100-quantum dot nanoparticles 200 structure as a whole. The inorganic material may be selected from silica, alumina (Al ₂ O ₃ , AlO ₂ ), titanium dioxide or zinc dioxide, and the polymer may be polystyrene or polymethylmethacrylate.

The quantum dot-containing particles and the inorganic or polymer shell may be bonded by covalent bonds, ionic bonds or physical adsorption. Particularly, the quantum dot-containing particles and the inorganic material may be formed by a functional group which includes an atom of any one of sulfur, nitrogen, or phosphorus bonded to the quantum dot nanoparticle on one side and the core particle or the inorganic or polymer shell on the other side. Covalent bonds can be made between the polymer shells.

When stable particles, such as inorganic or polymeric core particles, are used as the support for the quantum dots, it is easy to control the size of the core particles, and thus, quantum dot-containing particles having various sizes can be manufactured in a stable structure, thereby providing various characteristics. It has the characteristic that a fluorescent label can be obtained. Furthermore, due to the configuration in which at least one, preferably a plurality of quantum dot nanoparticles are bonded to the surface of the core particle, it has the advantage that the quantum yield (QY) is much greater than that of using a single quantum dot. do. That is, by controlling the size of the core particles, it is possible to control the size of the quantum dot nanoparticles as a ligand binding thereto, thereby having an advantage of easy control of the emission wavelength, while maximizing the number of quantum dot nanoparticles bound to the core particles. Thus, it has the advantage of maximizing the luminous efficiency. In other words, even if the luminous efficiency of the individual quantum dot nanoparticles is low, since they are attached to the core particles in a large amount, the luminous efficiency can be significantly improved as compared with the conventional quantum dots as a whole.

In particular, when the core particles and the quantum dot nanoparticles are bonded by covalent bonding, the strong bonding between the two prevents deterioration of stability due to photobleaching, and the long-term continuous use In addition, it is possible to maintain the unique light emission characteristics of the quantum dot.

The quantum dot-containing particles having the core particle-quantum dot nanoparticle structure of the present invention having the configuration of FIG. 1A are light emitting devices, such as light emitting diodes (LEDs), and single-electron transistors, using the excellent luminous efficiency and stability thereof. It can be applied to solar cell photosensitizer and light source. For example, a method of preparing a thin film by coating a composition including the quantum dot-containing particles on a substrate may be used.

In addition, the core particle-quantum dot nanoparticle-inorganic or polymer shell structure of the quantum dot-containing particles of the present invention as shown in Figure 1b, the inorganic material or the polymer shell having biocompatibility and hydrophilicity to prevent the expression of quantum dots inherent toxicity is best As coated on the outer portion, it can be utilized as a bio labeling material or a biolabeling tag.

Another object of the present invention can be achieved by providing a method for producing quantum dot-containing particles, comprising the step of bonding at least one quantum dot nanoparticles to the core particles in a hydrophilic organic solvent through covalent bonding, ionic bonding or physical adsorption. have.

The core particles used in the method of the present invention may be silica, alumina (Al ₂ O ₃ , AlO ₂ ), titanium dioxide or zinc dioxide. As an alternative, the core particles may be polystyrene or polymethylmethacrylate. It is preferable that the diameter of the said core particle is 2 micrometers-1,000 micrometers.

The quantum dot nanoparticles used in the method of the present invention is a single core structure consisting of a II-VI-based semiconductor, a III-V-based semiconductor, or a IV-IV-based semiconductor, or The group VI-based semiconductor may be capped core / shell structure. The diameter of the quantum dot nanoparticles is preferably 1 nm to 20 nm.

The method for preparing quantum dot-containing particles of the present invention may further include coating the core particles to which the quantum dot nanoparticles are bound with an inorganic material or a polymer through covalent bonding, ionic bonding, or physical adsorption. The inorganic material may be silica, alumina (Al ₂ O ₃ , AlO ₂ ), titanium dioxide, or zinc dioxide, and the polymer may be polystyrene or polymethylmethacrylate.

In the method of the present invention, the step of bonding at least one quantum dot nanoparticles to the core particles in the hydrophilic organic solvent through the covalent bond, (i) is selected from the group consisting of phosphine groups, amine groups and thiol groups on one side Modifying the surface of the core particles by reacting the core particles with a reactive compound including a functional group and a hydrophilic substituent on the other side in a hydrophilic organic solvent; And (ii) adding at least one quantum dot nanoparticle to the surface of the core particle by adding quantum dot nanoparticles to the hydrophilic organic solvent.

In addition, the step of coating the core particles to which the quantum dot nanoparticles are bonded through the covalent bond with an inorganic material or a polymer, the core particles to which the quantum dot nanoparticles are bonded, from the group consisting of a phosphine group, an amine group and a thiol group on one side Modifying the surface by reacting with a reactive compound comprising a functional group of choice and a hydrophilic substituent on the other; And reacting the silica with the modified surface to form a silica shell. In this case, the silica shell forming step may be performed by adding a tetraethoxysilane solution.

The functional group serves to bond the quantum dot nanoparticles with the core particles or the shell. The reactive functional groups impart hydrophilicity to the quantum dots having a hydrophobic surface, thereby allowing the quantum dots to bond with the core and the shell, which are hydrophilic materials, and to prevent the quantum dots from losing their luminescent properties for a long time. Therefore, such reactive functional groups must be provided with a hydrophilic moiety. Preferably such hydrophilic moieties should be exposed outwards relative to the quantum dot nanoparticles. Specifically, it is preferable to include an atom of any one of sulfur, nitrogen, or phosphorus directly bonded to the quantum dot nanoparticles on one side and a hydrophilic substituent bonded to the core particle or shell on the other side. .

The hydrophilic substituent is, for example, a silane group (silane group), amino group (amino group), sulfonic group (sulfonic group), carboxylic group (carboxylic group), isocyanate group (isocyantate group), azide group (azide group), Carbene or a hydroxyl group, and the like, but are not limited thereto. Most preferably it is preferable to have a silane group in order to bond with silica. That is, it is preferable that the said reactive functional group is a silane type functional group which has a silane group as a hydrophilic substituent.

As a silane compound for obtaining such a silane functional group, mercaptomethylmethylethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltriethoxysilane , 3-mercaptopropyltrimethoxysilane, 2-diphenylphosphinoethyltriethoxysilane, diphenylphosphinoethyldimethylethoxysilane, 3-aminopropyl Methyl diethoxysilane (3-aminopropylmethyldiethoxysilane), 3-aminopropyldimethylethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane ), 4-aminobutyltrimethoxysilane, 3- (meth-aminophenoxy) propyltri Methoxysilane (3- (maminophenoxy) propyltrimethoxysilane), and normal- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane (n- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane), and the like. It is not.

In addition, carboxylic acid or salts thereof, sulfonic acid or salts thereof, sulfamic acid or salts thereof, amino substituents, quaternary ammonium salts ), A hydroxyl group may be applied, and among these, thiol carboxylic acid or thiol alcohol is preferable. Among these, it is more preferable to use mercaptoacetic acid.

Hereinafter, referring to FIG. 2, a method of preparing quantum dot-containing particles according to an exemplary embodiment of the present invention will be described. In Fig. 2, silica particles are used as core particles, and silica shells are introduced as inorganic shells.

First, the method for manufacturing the quantum dot-containing silica particles of the present invention having the silica core particle 100-quantum dot nanoparticles 200 structure, including the first surface modification step (S10) and quantum dot bonding step (S20) Is done.

Surface modification step (S10)

The first surface modification step (S10) is a reactive compound for producing the aforementioned (reactive) functional group, and on one side, a phosphine-based, amine-based, or thiol-based functional group And reacting a compound including a hydrophilic substituent on the other side with the silica core particles in a hydrophilic organic solvent to modify the surface of the silica core particles. Here, as the hydrophilic organic solvent, a relatively hydrophilic solvent such as aqueous ammonia solution (NH ₄ OH (aq)), ethanol or methanol is used.

In FIG. 2, ethanol is used as a hydrophilic organic solvent, and 3-mercaptopropyltrimethoxysilane (hereinafter referred to as 'MPTS') is used as a reactive compound, and the silica core together with MPTS in the ethanol. A process of dispersing the particles 100 is shown. For example, 600 μl of 100 nm-sized silica nanoparticles mixed with MPTS at a concentration of 50 mg / ml is placed in an eppen tube, and then filled with 400 μl of ethanol or methanol to make 1 ml and reacted with stirring. By the reaction, the surface modification is performed while the thiol group is introduced to the surface of the silica core particles (100).

Quantum dot combining step (S20)

In the quantum dot bonding step (S20), solid phase quantum dot nanoparticles 200 are added to the hydrophilic organic solvent to bind at least one quantum dot nanoparticle to the surface of the silica core particles.

As described above, in the case of general quantum dot nanoparticles, a hydrophobic material such as TOPO is coated on the surface and dispersed in a hydrophobic solvent. The quantum dot nanoparticles dispersed in the hydrophobic solvent are dispersed in a hydrophilic (or ethanol, methanol, etc.) solvent. Since it is difficult to introduce dispersed silica particles directly, conventionally, amphiphilic polymers such as polyvinylpyrrolidone (PVP) are added, so that the hydrophobic portion is adjacent to the quantum dot surface and the hydrophilic portion is By facing outward, the surface properties of the entire nanoparticles were made hydrophilic, thereby modifying the surface of the quantum dot nanoparticles. However, when the surface modifier is added in this way, the luminous efficiency of the quantum dots generated by attaching and dropping foreign matters decreases, or when the surface modifier is first applied to the quantum dots and then introduced into the silica center particles, the silica center particles of the quantum dots are introduced. There is a problem that the introduction of the furnace may not be efficient. Accordingly, in the present invention, in order to hydrophilically modify the surface of the quantum dot without hydrolyzing the quantum dot nanoparticles without the addition of additional surface modifiers, only a very small amount of hydrophobic solvent is left on the surface of the quantum dot nanoparticles. The method of adding solid-state quantum dot nanoparticles as it is to the hydrophilic solvent in which the silica core particle 100 is disperse | distributed was used. As a result, the trace amount of hydrophobic solvent existing on the surface of the quantum dot nanoparticles is dissolved in a large amount of hydrophilic organic solvent (the hydrophobic: hydrophilic solvent ratio of 1: 1 or more), the quantum dot nanoparticles 200 are dispersed in the solvent Not shown, the silica core particles 100 will react in a dispersed form. Since the surface modification is performed so that the quantum dot nanoparticles 200 can be introduced into the silica core particles 100 well, the injected quantum dot nanoparticles 200 and the silica core particles 100 dispersed in the organic solvent are formed. Meet and combine.

Next, the method for producing the quantum dot-containing silica nanoparticles having the structure of the silica core particle 100-quantum dot nanoparticles 200-silica shell 300, the silica core particle 100-quantum dot nano After the production of the particle 200, it further comprises a second surface modification step (S30) and the shell coating step (S40).

Second surface modification step (S30)

The second surface modification step (S30) is a step of surface modification by reacting the quantum dot nanoparticles with the same reactive compound used in the first surface modification step (S10) after the quantum dot bonding step (S20). It is carried out in the same manner as the first surface modification step (S10).

Peel coating step (S40)

Shell coating step (S40) is a step of coating the silica 300 on the surface of the surface-modified quantum dot nanoparticles 200 after the second surface modification step (S30), for this purpose, the surface-modified silica core particles After dispersing the (100) -quantum dot nanoparticles 200 composite particles in a hydrophilic aqueous solution, a tetraethoxysilane (TEOS) solution and ammonia (NH ₄ OH) were added thereto, and a silica shell was formed on the surface of the composite particles. Induce to form. In the present invention, since the silica shell 300 becomes thicker as the amount of tetraethoxysilane (TEOS), which is a raw material of silica, increases, the size of the nanoparticles obtained by controlling the amount of TEOS can be controlled. The composite particles thus prepared are water soluble and are dispersed in water.

According to the method described above, when the quantum dot-containing silica nanoparticles of the present invention are prepared, the hydrophobic solvent in which the quantum dot nanoparticles are dispersed and the hydrophilic solvent in which the silica nanoparticles are dispersed are reacted by adding PVP to obtain composite nanoparticles. When the PVP is absorbed by the surface-modified silica-quantum dot composite nanoparticles, the silica shell is grown to about 1/2% of the quantum yield (QY) of the composite nanoparticles. When the silica shell is grown there, the QY is reduced by about 1/20. In addition, in the composite nanoparticles, the bonding between silica and quantum points is due to the electrostatic attraction (charge interaction), the bonding strength is weak, resulting in a decrease in stability due to photobleaching.

However, when the composite particles are manufactured according to the method for preparing quantum dot-containing particles of the present invention, the undispersed solid quantum dots are added as they are without addition of additional substances such as PVP during surface modification. In addition to minimization, since the bond between the silica and the quantum dots is due to covalent bonds significantly stronger than the electrostatic attraction, it is also possible to prevent deterioration of stability due to photobleaching. The quantum dot-containing particles according to the present invention prepared as described above can be used for various bio-system applications by combining various substances such as negatively charged genes, nucleic acids, antibodies, cancer cells and normal cells on the surface-modified silica shell surface, without silica shell When used to maximize the luminous efficiency, it can be applied to electronic products such as light emitting devices, single-electron transistors, photoresists for solar cells and light sources.

According to the present invention, the luminous efficiency is excellent and the number of quantum dots introduced is also large, and each nanoparticle can exhibit strong fluorescence characteristics, and when used by itself without surface modification, it can be utilized as a flat panel display element. When the outermost silica coating is carried out, the target material to be labeled can be analyzed with sensitive sensitivity, high stability due to no photobleaching, and simple surface modification can be used as a bioanalytical display material.

In addition, according to the present invention, by using the silica nanoparticles as a core support, it has a stable structure, it is possible to not only more various labels, but also has the advantage that the particle size can be adjusted. Because of these advantages, it can be widely used in the fields of medicine, pharmacy and chemistry, as well as electrical and electronics, such as the detection of biological materials.

1A and 1B show an embodiment of the quantum dot-containing particles of the present invention, respectively.

2 is a flowchart showing a method for producing quantum dot-containing particles according to one preferred embodiment of the present invention.

3A and 3B are electron micrographs of the silica core-quantum dot composite particle and the silica core-quantum dot-silica shell composite particle, respectively prepared according to the embodiment of the present invention.

Figure 4 is a photograph of the results of observing each sample of A, B, C prepared by the embodiment of the present invention in the dark room with an ultraviolet lamp.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following description of the embodiments is only intended to specifically describe the specific embodiments of the present invention, it is not intended to limit or limit the scope of the present invention to the contents described therein.

실시예 1. 실리카 나노입자 코어의 제조Example 1 Preparation of Silica Nanoparticle Cores

Silica nanoparticle cores of various sizes were prepared by the Stover method or the microemulsion method. The silica nanoparticle cores prepared by the Stober method were 100 nm in diameter, 200 nm, and 400 nm in size, and the microemulsion method was 50 nm in size. In addition, the content of the magnetic material in the silica quantified by Inductively Coupled Plasma (ICP) analysis was 25 mg / ml.

실시예 2. 실리카 나노입자 코어에 양자점 나노 입자의 도입Example 2 Introduction of Quantum Dot Nanoparticles to Silica Nanoparticle Cores

10 ml of 1% (v / v) 3-mercaptopropyltrimethoxysilane (MPTS) and 25% aqueous ammonia (NH ₄ ) in 1 ml of the silica nanoparticle core prepared in Example 1 10 μl of OH (aq)) was added and stirred at 25 ° C. for 12 hours to introduce a thiol group to the silica nanoparticle core surface. In order to bind the quantum dot nanoparticles to generate fluorescence around the silica nanoparticle core into which the thiol group was introduced, the magnetic nanoparticle core was washed with ethanol, and then 10 mg of quantum dot nanoparticles (CdSe / ZnS) were added. After stirring for 5 minutes. Then chloroform solution was added and stirred for another 10 minutes. Subsequently, the silica nanoparticle core (composite nanoparticles) into which the quantum dot nanoparticles precipitated by centrifugation was introduced, and the remaining filtrate was removed. The precipitated composite nanoparticles were stirred to be well dispersed in chloroform. Electron micrographs of the composite nanoparticles thus prepared are shown in FIG. 3A.

실시예 3. 양자점 나노입자가 도입된 실리카 나노입자 코어의 표면개질Example 3 Surface Modification of Silica Nanoparticle Cores Incorporated with Quantum Dot Nanoparticles

In order to coat the silica shell on the composite particles obtained in Example 2, 200 μl of MPTS was added, followed by stirring at 25 ° C. for 15 minutes. This was then washed three times with ethanol to obtain a surface-modified silica-quantum dot composite particle.

실시예 4. 표면개질된 실리카-양자점 복합입자 표면에 대한 실리카 껍질의 형성Example 4 Formation of Silica Shells on Surface-Modified Silica-Quantum Composite Particle Surfaces

In order to form a silica shell around the composite particles obtained in Example 3, the composite particles were dispersed in 1 ml of an aqueous solution, 20 μl of TEOS was added thereto, and stirred at 25 ° C. for 12 hours. The obtained particle aggregate was washed three times with water and ethanol, respectively. This gave silica shell-coated silica-quantum dot composite particles, that is, quantum dot-containing silica nanoparticles according to the present invention (luminescence color: green). Electron micrographs of the composite nanoparticles thus prepared are shown in FIG. 3B.

실시예 5. 발광효율(quantum yield, QY)의 측정Example 5 Measurement of Quantum Yield (QY)

The quantum dot-containing silica nanoparticles prepared in Example 4 was confirmed whether and the degree of light emission with an ultraviolet lamp (UV LAMP) in the dark room, and specifically measured the QY. QY measurements were performed using an integrating sphere system of the Jasco FP-6500 Spectroflurometer. The measurement object was a dispersion (A) of only the silica nanoparticles obtained in Example 1, a particle dispersion (B) in which a quantum dot was introduced into the silica surface obtained in Example 2, and a silica shell introduced in Example 4- It was a quantum dot composite particle (C).

First, as shown in FIG. 4, when the samples of A, B, and C were observed with an ultraviolet lamp in a dark room, pure silica nanoparticles (A) do not emit light, whereas B and C emit light. It was found that, even if visually confirmed, it can be seen that the degree of light emission of C rather than B is somewhat weak. This is due to the addition of silica shells as described above, and the quantitative QY for this is shown in Table 1 below.

Table 1

Sample	QY (%)	Difference
Unique QY of quantum dots (Cd / Se / ZnS)	40	-
B	26	-14
C	10	-16

That is, as shown in Table 1, the intrinsic QY of the CdSe / ZnS quantum dot nanoparticles having the core / shell structure is 40%, and when the quantum dots are introduced into the silica nanoparticle core (B), about 14% of the luminescence loss is lost. When the silica shell was coated here (C), there was an additional 16% luminescence loss. However, it can be seen that the degree of deterioration is considerably smaller than in the case of manufacturing by the conventional method in which PVP and the like are added.

Claims

Inorganic or polymeric core particles; And at least one quantum dot nanoparticle bonded to a surface of the core particle.
The quantum dot-containing particles according to claim 1, wherein the inorganic core particles are selected from the group consisting of silica, alumina (Al 2 O 3 , AlO 2 ), titanium dioxide and zinc dioxide.
The quantum dot-containing particles according to claim 1, wherein the polymer core particles are polystyrene or polymethyl methacrylate.
The quantum dot-containing particles according to claim 1, wherein the core particles and the quantum dot nanoparticles are bonded by a bond selected from the group consisting of covalent bonds, ionic bonds, and physical adsorption.
The covalent bond according to claim 4, wherein the covalent bond is formed by a functional group containing one atom of sulfur, nitrogen, or phosphorus bonded to the quantum dot nanoparticle on one side and bonded to the core particle on the other side. Quantum dot-containing particles.
The quantum dot-containing particle according to claim 5, wherein the functional group is selected from the group consisting of a silane group, an amino group, a sulfone group, a carboxy group and a hydroxyl group.
The quantum dot-containing particles according to claim 1, wherein the core particles have a diameter of 2 µm to 1,000 µm.
The method according to claim 1, wherein the quantum dot nanoparticle is a single core structure consisting of any one selected from the group consisting of a II-VI-based semiconductor, a III-V-based semiconductor and a IV-IV-based semiconductor, or A quantum dot-containing particle, characterized in that the core / shell structure of the group II-VI-based semiconductor is capped in a single core structure.
The quantum dot-containing particles according to claim 1, wherein the quantum dot nanoparticles have a diameter of 1 nm to 20 nm.
The quantum dot-containing particles according to claim 1, further comprising an inorganic material or a polymer shell covering the quantum dot-containing particles.
The quantum dot-containing particles according to claim 10, wherein the inorganic material is selected from the group consisting of silica, alumina (Al 2 O 3 , AlO 2 ), titanium dioxide and zinc dioxide.
The quantum dot-containing particles according to claim 10, wherein the polymer is polystyrene or polymethyl methacrylate.
The quantum dot-containing particles according to claim 10, wherein the quantum dot-containing particles and the inorganic or polymer shell are bonded by a bond selected from the group consisting of covalent bonds, ionic bonds, and physical adsorption.
12. The functional group according to claim 11, wherein the covalent bond comprises an atom of any one of sulfur, nitrogen or phosphorus bonded to the quantum dot nanoparticle on one side and bonded to the core particle or the inorganic or polymer shell on the other side. Quantum dot-containing particles, characterized in that consisting of.
Bonding at least one quantum dot nanoparticle to the core particle in a hydrophilic organic solvent through covalent bonding, ionic bonding or physical adsorption.
The method of claim 15, further comprising coating the core particles to which the quantum dot nanoparticles are bound with an inorganic material or a polymer through covalent bonding, ionic bonding, or physical adsorption.
The method of claim 15, wherein the core particles are selected from the group consisting of silica, alumina (Al 2 O 3 , AlO 2 ), titanium dioxide, and zinc dioxide.
The method for producing quantum dot-containing particles according to claim 15, wherein the core particles are polystyrene or polymethyl methacrylate.
The method of claim 15, wherein the core particles have a diameter of 2 μm to 1,000 μm.
The method of claim 15, wherein the quantum dot nanoparticle is a single core structure consisting of any one selected from the group consisting of a semiconductor of the II-VI series, a semiconductor of the III-V series and a semiconductor of the IV-IV series, or A method for producing quantum dot-containing particles, characterized in that the single-core structure is a core / shell structure in which a II-VI-based semiconductor is capped.
16. The method of claim 15, wherein the quantum dot nanoparticles have a diameter of 1 nm to 20 nm.
The method of claim 15, wherein the step of coupling at least one quantum dot nanoparticles to the core particles in the hydrophilic organic solvent through the covalent bond,

(i) Reacting the surface of the core particles by reacting the core particles with a reactive group comprising a functional group selected from the group consisting of a phosphine group, an amine group and a thiol group on one side and a hydrophilic substituent on the other side in a hydrophilic organic solvent. Making; And

(ii) adding at least one quantum dot nanoparticle to the surface of the core particle by adding quantum dot nanoparticles to the hydrophilic organic solvent,

Method for producing quantum dot-containing particles.
The method of claim 16, wherein the coating the core particles to which the quantum dot nanoparticles are bonded through the covalent bond with an inorganic material or a polymer shell,

Modifying the surface by reacting the quantum dot nanoparticle-bound core particles with a reactive compound including a functional group selected from the group consisting of a phosphine group, an amine group and a thiol group on one side and a hydrophilic substituent on the other side; And

Reacting the inorganic surface or the polymer with the modified surface to form a shell, characterized in that

Method for producing quantum dot-containing particles.
The method of claim 22, wherein the hydrophilic substituent is selected from the group consisting of a silane group, an amino group, a sulfone group, a carboxyl group, an isocyanate group, an azide group, a carbene group, and a hydroxyl group.
The method for producing quantum dot-containing particles according to claim 22, wherein the hydrophilic substituent is a silane group.
24. The method of claim 23, wherein the silica shell forming step is performed by adding a tetraethoxysilane solution.
The method for producing quantum dot-containing particles according to claim 16 or 23, wherein the inorganic material is selected from the group consisting of silica, alumina (Al 2 O 3 , AlO 2 ), titanium dioxide and zinc dioxide.
The method for producing quantum dot-containing particles according to claim 16 or 23, wherein the polymer is polystyrene or polymethyl methacrylate.