JPWO2013035362A1 - Ion-resistant semiconductor nanoparticle assembly - Google Patents

Abstract

[Problem] To provide semiconductor nanoparticles free from ion elution of constituent elements of semiconductor nanoparticles in an aqueous solution. [Solution] It is possible to provide a semiconductor nanoparticle aggregate that solves the above-mentioned problems by enclosing semiconductor nanoparticles with a water-soluble semiconductor nanoparticle aggregate and having a core / shell structure inside together with a surfactant. It becomes.

Description

  The present invention relates to a semiconductor nanoparticle assembly having high luminance and no ion elution in an aqueous solution. More specifically, the present invention relates to a matrix-coated assembly in which a semiconductor nanoparticle assembly containing semiconductor nanoparticles having a core / shell structure and a surfactant are coated with a silica matrix, and a method for producing the same.

  When semiconductor nanoparticles that emit fluorescence are used as the labeling agent, the higher the luminance per particle, the higher the sensitivity. Therefore, particles with higher luminance per particle are desired.

  As semiconductor nanoparticles that emit fluorescence, II-VI and III-V semiconductor nanoparticles are widely known. However, when these semiconductor nanoparticles are used as a fluorescent diagnostic agent, the problem is that the brightness per particle is still insufficient, and that ions constituting the semiconductor nanoparticles leak out in an aqueous solution. Yes.

  On the other hand, in general, the brightness of the particles is extremely low with only the core semiconductor nanoparticles as compared with the semiconductor nanoparticles having a core / shell structure. By using a semiconductor material having a wider band gap than the core particles as the shell, quantum wells are formed, and the luminance is significantly improved by the quantum confinement effect.

  Therefore, as a method of increasing the brightness, a method of increasing the brightness per particle by integrating the core / shell semiconductor nanoparticles can be considered.

  For example, Patent Document 1 discloses that a silica bead surface is converted to an amino group by silane coupling treatment, and a carboxyl group-terminated semiconductor nanoparticle is reacted to bond the silica bead and the semiconductor nanoparticle by an amide bond. Techniques for making them disclosed are disclosed. However, cadmium ion elution is observed even in the semiconductor nanoparticle assembly produced in this way. For example, when used for labeling a substance, elution of cadmium into cells causes a decrease in safety and further deterioration of the phosphor. It is done.

JP 2005-281019 A

  An object of the present invention is to provide a semiconductor nanoparticle assembly in which ions constituting the semiconductor nanoparticles are less likely to elute in an aqueous solvent.

The present inventors can obtain the core / shell structure semiconductor nanoparticles thus precipitated by stirring with a higher amine as a surfactant and water and then hydrolyzing TEOS with ethanol and NH _3. The present inventors have found that the matrix-covered aggregate (semiconductor nanoparticle-encapsulated particles) has less elution of ions forming the core portion, and has completed the present invention.

  That is, the present invention includes the following matters.

  [1] A semiconductor nanoparticle aggregate containing semiconductor nanoparticles having a core / shell structure, to which a surfactant is bound, and the semiconductor nanoparticle aggregate to which the surfactant is bound A matrix-coated assembly comprising a silica matrix.

  [2] The matrix-coated assembly according to [1], wherein the surfactant is a higher amine.

  [3] The matrix-coated aggregate according to [1] or [2], wherein the core part of the core / shell structure is indium phosphide [InP], cadmium selenide [CdSe], or cadmium telluride [CdTe].

[4] Step (X) of water-solubilizing a semiconductor nanoparticle aggregate containing semiconductor nanoparticles having a core / shell structure using an amount of a surfactant that exceeds a limit amount that dissolves in water; and step (X And a step (Y) of coating the periphery of the water-solubilized semiconductor nanoparticle aggregate obtained in (1) with a silica matrix.

  [5] The production method according to [4], wherein the surfactant is a higher amine.

[6] The silica matrix is obtained by adding ethanol, ammonia [NH ₃ ] and tetraethoxysilane [TEOS] in this order to the water-soluble semiconductor nanoparticle aggregate obtained in the step (X) [ 4] or the production method according to [5].

  [7] The method according to any one of [4] to [6], wherein the core part of the core / shell structure is indium phosphide [InP], cadmium selenide [CdSe], or cadmium telluride [CdTe]. .

  In the present invention, when an aqueous solution containing a 0.1 μM matrix-coated aggregate is allowed to stand for 1 day, the elution of ions forming the core portion is 100 ppm or less, preferably 50 ppm or less, more preferably 10 ppm or less. An integrated body and a manufacturing method thereof can be provided.

  Furthermore, the present invention can provide a matrix-covered aggregate with high emission luminance and a method for producing the same without reducing the emission intensity even when the concentration of the semiconductor nanoparticle aggregate that emits fluorescence is less than a certain level.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail.

<Matrix coating assembly>
The matrix-covered aggregate of the present invention includes a semiconductor nanoparticle aggregate containing semiconductor nanoparticles having a core / shell structure, to which a surfactant is bound, and the semiconductor nanoparticle to which the surfactant is bound. And a silica matrix covering the particle aggregate.

  As an embodiment of the present invention, it is preferable to produce semiconductor nanoparticle aggregates by hydrolyzing semiconductor nanoparticles with TEOS in the presence of a surfactant such as amine.

[Semiconductor nanoparticles having a core / shell structure]
The “semiconductor nanoparticle having a core / shell structure” used in the present invention is a particle having a nanosize (1 to 1000 nm) particle size containing a material (material) for forming a semiconductor described later, and having a core part A particle having a multiple structure composed of a (core part) and a shell part (covering part) covering the core part.

(Core part)
Examples of the material for forming the core portion (also referred to as “core particle”) according to the present invention include silicon [Si], germanium [Ge], indium nitride [InN], indium phosphide [InP], and arsenic. Gallium phosphide [GaAs], aluminum selenide [AlSe], cadmium selenide [CdSe], aluminum arsenide [AlAs], gallium phosphide [GaP], zinc telluride [ZnTe], cadmium telluride [CdTe], arsenic A semiconductor such as indium [InAs] or indium-gallium-phosphorus [InGaP] or a raw material for forming these can be used.

  In the present invention, InP, CdTe or CdSe is particularly preferably used.

(Shell part)
As a material for forming the shell portion according to the present invention, II-VI group, III-V group, and IV group inorganic semiconductors can be used. For example, the core portion forming inorganic material such as Si, Ge, InN, InP, GaAs, AlSe, CdSe, AlAs, GaP, ZnTe, CdTe, InAs or the like has a larger band gap and does not have toxicity. Raw materials are preferred.

  More preferably, ZnS is applied as a shell part to the core part of InP, CdTe, or CdSe.

  Hereinafter, in this specification, as a notation method of the semiconductor nanoparticles having a core / shell structure, for example, when the core part is CdSe and the shell part is ZnS, it may be expressed as “CdSe / ZnS”.

(Method for producing semiconductor nanoparticles)
As a method for producing semiconductor nanoparticles according to the present invention, a liquid phase method can be employed.

  Examples of the liquid phase method include a precipitation method, a coprecipitation method, a sol-gel method, a uniform precipitation method, and a reduction method. In addition, the reverse micelle method, the supercritical hydrothermal synthesis method, and the like are also excellent methods for producing semiconductor nanoparticles (for example, JP 2002-322468 A, JP 2005-239775 A, and JP 10 Hei 10). No. -371070, JP-A No. 2000-104058, etc.).

In addition, when manufacturing the semiconductor nanoparticle aggregate | assembly (semiconductor nanoparticle aggregate | assembly) mentioned later by a liquid phase method, it is also preferable that it is a manufacturing method which has the process of reduce | restoring the said semiconductor precursor by a reductive reaction. . (* The reducing agent that reduces the semiconductor precursor will be described later.)
Moreover, the aspect which has the process of reacting the said semiconductor precursor in presence of surfactant (* mentioned later) is preferable. The semiconductor precursor according to the present invention is a compound containing an element used as the semiconductor material, for example, when the semiconductor is Si, and the like SiCl ₄ as semiconductor precursor. Other semiconductor precursors include InCl ₃ , P (SiMe ₃ ) ₃ , ZnMe ₂ , CdMe ₂ , GeCl ₄ , tributylphosphine selenium and the like.

The reaction temperature of the reaction precursor is not particularly limited as long as it is not lower than the boiling point of the semiconductor precursor and not higher than the boiling point of the solvent, but is preferably in the range of 70 to 110 ° C.
* Reducing agent that reduces the semiconductor precursor:
As such a reducing agent, various conventionally known reducing agents can be selected and used according to the reaction conditions. In the present invention, from the viewpoint of the strength of reducing power, lithium aluminum hydride [LiAlH ₄ ], sodium borohydride [NaBH ₄ ], sodium bis (2-methoxyethoxy) aluminum hydride, tri (sec- butyl) boron lithium _{[LiBH (sec-C 4 H 9} ) 3 ] and hydrogenated tri (sec-butyl) potassium boron reducing agent such as lithium triethylborohydride being preferred. In particular, lithium aluminum hydride [LiAlH ₄ ] is preferable because of its reducing power.
* Surfactant used for reaction of semiconductor precursor:
As such a surfactant, various conventionally known surfactants can be used, and anionic, nonionic, cationic, and amphoteric surfactants are included. Of these, tetrabutylammonium chloride, bromide or hexafluorophosphate, tetraoctylammonium bromide [TOAB] or tributylhexadecylphosphonium bromide, which are quaternary ammonium salts, are preferred. Tetraoctyl ammonium bromide is particularly preferable.

The reaction by the liquid phase method varies greatly depending on the state of the compound containing the solvent in the liquid (* described later). When producing nano-sized particles with excellent monodispersity, special care must be taken. For example, in the reverse micelle reaction method, the size and state of the reverse micelle serving as a reaction field vary depending on the concentration and type of the surfactant, so that the conditions under which nanoparticles are formed are limited. Therefore, an appropriate combination of surfactant and solvent is required.
* Solvent used in the liquid phase method:
As the solvent for dispersing the semiconductor precursor, various conventionally known solvents can be used. Alcohols such as ethyl alcohol, sec-butyl alcohol and t-butyl alcohol; hydrocarbon solvents such as toluene, decane and hexane are used. It is preferable to use it. In the present invention, a hydrophobic solvent such as toluene is particularly preferable as the dispersion solvent.

[Semiconductor nanoparticle assembly]
The semiconductor nanoparticle assembly used in the present invention is an assembly of semiconductor nanoparticles containing semiconductor nanoparticles having a core / shell structure.

  Calculation of the inclusion number of the semiconductor nanoparticles in the integrated body is performed as follows. First, the element ratio of semiconductor nanoparticles is measured using ICP-AEC (ICPS-7500, Shimadzu Corporation), and the number of moles is calculated from the dry weight. Further, the molar extinction coefficient is obtained by measuring the absorbance. Thereafter, the dry weight of the semiconductor nanoparticle assembly is calculated and the absorbance is measured. Since the density of the semiconductor nanoparticle and the semiconductor nanoparticle assembly constituent compound is known, the concentration can be estimated together with the average particle size calculated by the dynamic light scattering method and the absorbance of the semiconductor nanoparticle assembly.

(Manufacturing method of semiconductor nanoparticle assembly)
As a manufacturing method of the semiconductor nanoparticle assembly, a liquid phase method may be used as described above, or another manufacturing method may be used. Examples of other manufacturing methods include gas phase methods such as sputtering. Among these, from the viewpoint of particle size uniformity, a method for producing a semiconductor nanoparticle assembly by a liquid phase method is preferred.

[Surfactant]
Examples of the surfactant used in the present invention include higher amines such as dodecylamine, hexadecylamine, and octadecylamine, and organic phosphorus compounds such as trioctylphosphine and trioctylphosphine oxide. For this reason, higher amines are preferred.

<Method for producing matrix-coated assembly>
The method for producing a matrix-covered aggregate of the present invention includes at least the following steps (X) and (Y).

  Process (X): The process of making the semiconductor nanoparticle aggregate | assembly containing the semiconductor nanoparticle which has a core / shell structure water-soluble using the quantity of surfactant exceeding the limit quantity melt | dissolved in water.

  Step (Y): A step of coating the periphery of the water-soluble semiconductor nanoparticle aggregate obtained in the step (X) with a matrix.

  The surfactant and matrix are the same as those described above.

Specifically, as a method for producing a matrix-covered aggregate when silica is used as the matrix, first, the semiconductor nanoparticles are water-solubilized with a surfactant (step (X)). Here, an amine compound can be used as the surfactant, and it is particularly preferable to use a higher amine such as dodecylamine. The semiconductor nanoparticles solubilized with this surfactant are added with ethanol, ammonia [NH ₃ ] and tetraethoxysilane [TEOS] in this order to hydrolyze TEOS, and the semiconductor nanoparticles are coated with a silica matrix. A body, that is, a matrix-coated aggregate can be obtained (step (Y)). Note that the matrix-covered aggregate contains little or no water that acts as a catalyst for the TEOS reaction.

  In the step (X) in the case of using dodecylamine as a surfactant, dodecylamine is added in an amount exceeding the limit amount that dissolves in water (for example, 78 mg / L at 25 ° C.). Use of an amount exceeding the limit amount for dissolving the surfactant in water is preferable in that the semiconductor nanoparticles having a core / shell structure are water-solubilized.

  In general, when a small amount of a surfactant other than an amine compound or an organic phosphorus compound is added to water, the semiconductor nanoparticles having a core / shell structure are water-solubilized. However, for example, when dodecylamine is used as the surfactant, the semiconductor nanoparticles do not become water-soluble unless a large amount of the surfactant exists because the water solubility of dodecylamine itself is extremely low. When dodecylamine is added in an amount that dissolves in water, the semiconductor nanoparticles are not mixed with water and completely separated from the aqueous phase.

  Further, by adding dodecylamine in an amount exceeding 100 times that of the semiconductor nanoparticles by molar ratio, the phase of dodecylamine is separated into an aqueous phase in which the semiconductor nanoparticles are present. On the other hand, when the molar ratio is 100 times or less, the semiconductor nanoparticles are also present in the dodecylamine phase. This can be confirmed visually by irradiating with a UV lamp.

  That is, the surfactant used in the present invention with respect to the semiconductor nanoparticles having a core / shell structure is preferably 10 to 400, more preferably in molar ratio [(surfactant) / (the semiconductor nanoparticles)]. Is added to water in an amount satisfying about 50 to 200, most preferably about 100.

  The hydrolysis of TEOS is represented by the following reaction formula.

Hydrolysis:
{Si (OC ₂ H ₅ ) ₄ } + x {H ₂ O} → {Si (OH) (xOC ₂ H ₅ ) _4-x } + {C ₂ H ₅ OH}
dehydration:
{-Si-OH} + {HO-Si-} → {-Si-O-Si-} + {H ₂ O}
Dealcohol:
{-Si-OC ₂ H ₅ } + {HO-Si-} → {-Si-O-Si-} + {C ₂ H ₅ OH}
By repeating such hydrolysis, dehydration and dealcoholization reactions, SiO ₂ constituting the silica matrix is produced from TEOS.

  The reaction formula for the overall hydrolysis of TEOS is shown below.

{Si (OC ₂ H ₅ ) ₄ } +2 {H ₂ O} → {SiO ₂ } +4 {C ₂ H ₅ OH}
Such a matrix-covered aggregate of the present invention is excellent in that in the ion elution test, elution of ions forming the core portion is extremely small, specifically 100 ppm or less, preferably 50 ppm or less, more preferably 10 ppm or less. It has the effect. This ion elution test is a core / shell that is dispersed in an aqueous solvent at a concentration of 0.1 μM and left to stand overnight (for example, 8 to 16 hours, to 24 hours, etc.) and then oozes into the supernatant. In this test, the amount of ions of constituent elements of the semiconductor nanoparticles having a structure is measured, and the degree of elution of ions of the matrix-covered aggregate is evaluated. The ion amount was measured by using an inductively coupled plasma-atomic emission spectrometer (ICP-AES).

  The outline of the matrix-coated aggregate, the method for producing the matrix-coated aggregate, and the ion elution test of the matrix-coated aggregate have been described above.

<Application example of matrix coating assembly>
Below, the typical application example of a matrix coating | stacking assembly is demonstrated.

[Biological substance labeling agents and bioimaging]
The matrix-coated assembly of the present invention can be applied to a biological material fluorescent labeling agent. Further, by adding the biological material labeling agent according to the present invention to a living cell or living body having a target (tracking) substance, the target substance is bound or adsorbed, and excitation light having a predetermined wavelength is applied to the conjugate or adsorbent. By irradiating and detecting fluorescence of a predetermined wavelength emitted from the semiconductor nanoparticles according to the excitation light, fluorescence dynamic imaging of the target (tracking) substance can be performed.

  That is, the biomaterial labeling agent using the present invention can be used for bioimaging methods (technical means for visualizing biomolecules constituting the biomaterial and dynamic phenomena thereof).

(Biological substance labeling agent)
The biological substance labeling agent using the present invention is obtained by binding the matrix-coated aggregate subjected to the hydrophilic treatment as described above and a molecular labeling substance (* described later) via an organic molecule (* described later). It is preferred that
* Molecular labeling substance:
The biological substance labeling agent using the present invention can be labeled with a biological substance when the molecular labeling substance specifically binds and / or reacts with the target biological substance.

Examples of the molecular labeling substance include nucleotide chains, antibodies, antigens, cyclodextrins and the like.
* Organic molecules:
In the biological material labeling agent using the present invention, the matrix-coated aggregate subjected to the hydrophilization treatment and the molecular labeling material are bound by organic molecules. The organic molecule is not particularly limited as long as it is an organic molecule that can bind the matrix-covered aggregate and the molecular labeling substance. For example, proteins such as albumin, myoglobin, casein, or avidin that is a kind of protein. It is also suitable to use with biotin. The form of the bond is not particularly limited, and examples thereof include a covalent bond, an ionic bond, a hydrogen bond, a coordinate bond, physical adsorption, and chemical adsorption. A bond having a strong bonding force such as a covalent bond is preferable from the viewpoint of bond stability.

  Specifically, when the matrix-coated aggregate is hydrophilized with mercaptoundecanoic acid, avidin and biotin can be used as organic molecules. In this case, the carboxyl group of the matrix-coated assembly subjected to the hydrophilic treatment is preferably covalently bonded to avidin, the avidin is further selectively bonded to biotin, and biotin is further bonded to the biological material labeling agent to thereby bind the biological material labeling agent. It becomes.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these. In addition, the ratio of the element in an Example and a comparative example shows molar ratio.

[Comparative Example 1] Synthesis of semiconductor nanoparticles having a core / shell structure of InP / ZnS:
InP core particles were synthesized according to the following heated solution method.

Put 6 mL of octadecene into a three-necked flask, and mix In (acac) ₃ and tris (trimethylsilyl) phosphine dissolved in 1 mL of octadecene in the solvent so that the ratio of In to P becomes In / P = 1/1. In addition, an InP core particle (dispersion) was obtained by reacting at 300 ° C. for 1 hour in an argon atmosphere.

  InP / ZnS core / shell particles were synthesized by allowing the InP core particle dispersion after reaction at 300 ° C. for 1 hour to cool to 80 ° C., and then adding zinc stearate + sulfur dissolved in 1 mL of octadecene to the dispersion. , P, Zn and S were added so that the ratio of In / P / Zn / S = 1/1/1/1 was increased from 80 ° C. to 230 ° C. and reacted for 30 minutes.

  The thus obtained InP / ZnS core / shell semiconductor nanoparticles were particles having a maximum emission wavelength at 630 nm.

[Comparative Example 2] Synthesis of semiconductor nanoparticles having a core / shell structure of CdSe / ZnS:
CdSe / ZnS core / shell semiconductor nanoparticles were synthesized as follows.

  Under an Ar stream, 2.9 g of stearic acid, 620 mg of n-tetradecylphosphonic acid, and 250 mg of cadmium oxide were added to 7.5 g of tri-n-octylphosphine oxide [TOPO], and the mixture was heated and mixed at 370 ° C. After allowing this to cool to 270 ° C., a solution of 200 mg of selenium dissolved in 2.5 mL of tributylphosphine was added and dried under reduced pressure to obtain CdSe core semiconductor nanoparticles coated with TOPO.

  CdSe / ZnS core / shell semiconductor nanoparticle synthesis was conducted by adding 15 g of TOPO to the obtained CdSe core particles and heating, followed by adding a solution of 1.1 g of zinc diethyldithiocarbamate in 10 mL of trioctylphosphine at 270 ° C. / ZnS core / shell semiconductor nanoparticles were obtained.

[Comparative Example 3] Synthesis of semiconductor nanoparticles having a core / shell structure of CdTe / ZnS:
CdTe / ZnS core / shell semiconductor nanoparticles were synthesized according to Example 1 described in JP-A-2005-281019.

  CdTe core particles were synthesized according to the method according to Chemie, Vol. 100, page 1772 (1996).

That is, hydrogen telluride gas while vigorously stirring an aqueous cadmium perchlorate solution adjusted to 25 ° C. and pH = 11.4 in the presence of thioglycolic acid [HOOCCH ₂ SH] as a surfactant under an argon gas atmosphere Was reacted. The aqueous solution was refluxed for 6 days in an air atmosphere to obtain CdTe core particles.

  The CdTe core particles thus obtained were particles having a maximum emission wavelength at 640 nm.

  CdTe / ZnS core / shell semiconductor nanoparticles were synthesized by heating this aqueous solution to 80 ° C., and then adding zinc stearate + sulfur dissolved in 1 mL of water to the solution so that the ratio of Cd, Te, Zn, S was In. It was obtained by adding / P / Zn / S = 1/1/1/1, raising the temperature from 80 ° C. to 230 ° C., and reacting for 30 minutes.

[Comparative Example 4] Fabrication of semiconductor nanoparticle assembly in which CdTe / ZnS is present in a silica matrix:
According to Example 1 described in Japanese Patent Application Laid-Open No. 2005-281019, a semiconductor nanoparticle aggregate in which CdTe / ZnS is present in a silica matrix was produced.

  The CdTe / ZnS core / shell semiconductor nanoparticle dispersion was water-solubilized by adding thioglycolic acid as a surfactant under the conditions of 25 ° C. and pH = 10. Thereafter, sodium bis (2-ethylhexyl) sulfosuccinate (aerosol OT) necessary for forming reverse micelles (reverse microemulsions) in 25 mL of isooctane (2,2,4-trimethylpentane) as a hydrophobic organic solvent. (Also referred to as “AOT”) 1.1115 g was dissolved, and then 0.74 mL of water and 0.3 mL of the water-soluble CdTe / ZnS core / shell semiconductor nanoparticle solution were added while stirring the solution. And dissolved. Next, while stirring this solution, 0.399 mL of tetraethoxysilane [TEOS], which is an alkoxide, and 3-aminopropyltrimethoxysilane [APS], which is an organic alkoxysilane, are used as sol-gel glass precursors. 079 mL was added.

  This dispersion was stirred for 2 days to obtain a semiconductor nanoparticle aggregate in which CdTe / ZnS was present in the silica matrix.

[Comparative Example 5] Preparation of semiconductor nanoparticles in which CdTe / ZnS and dodecylamine were swollen in a polystyrene matrix:
Using the CdTe / ZnS core / shell semiconductor nanoparticles synthesized in Comparative Example 3, acetone, which is a poor solvent, was added to the core / shell semiconductor nanoparticle solution to precipitate the semiconductor nanoparticles.

  To 0.1 mg of this precipitate, 0.1 mg of dodecylamine as a surfactant and 1 mL of ultrapure water were added and stirred strongly for 1 h to obtain a water-soluble semiconductor nanoparticle solution.

  CdTe / ZnS semiconductor nanoparticles were swollen in polystyrene by adding carboxyl group-terminated polystyrene particles (300 nm) manufactured by Invitrogen to this water-soluble semiconductor nanoparticle solution and stirring strongly for 1 h.

[Example 1]
Acetone, which is a poor solvent, was added to the solution of InP / ZnS core / shell semiconductor nanoparticles synthesized in Comparative Example 1 to precipitate the semiconductor nanoparticles.

  To 0.1 mg of this precipitate, 0.1 mg of dodecylamine as a surfactant and 1 mL of ultrapure water were added and stirred strongly for 1 h to obtain a water-soluble semiconductor nanoparticle solution.

To this water-soluble semiconductor nanoparticle solution, 0.1 mg of TEOS, 0.01 mL of ethanol, and 0.03 mL of NH ₃ were added in this order, and TEOS was hydrolyzed to obtain a matrix-covered aggregate.

[Example 2]
In Example 1, the same procedure as in Example 1 was used except that the CdSe / ZnS core / shell semiconductor nanoparticles synthesized in Comparative Example 2 were used instead of the InP / ZnS core / shell semiconductor nanoparticles synthesized in Comparative Example 1. A matrix coating assembly was produced.

[Example 3]
In Example 1, the same procedure as in Example 1 was used except that the CdTe / ZnS core / shell semiconductor nanoparticles synthesized in Comparative Example 3 were used instead of the InP / ZnS core / shell semiconductor nanoparticles synthesized in Comparative Example 1. A matrix coating assembly was produced.

[Example 4]
In Example 1, the CdTe / ZnS core / shell semiconductor nanoparticles synthesized in Comparative Example 3 were used instead of the InP / ZnS core / shell semiconductor nanoparticles synthesized in Comparative Example 1, and instead of dodecylamine as a surfactant. A matrix-coated assembly was produced in the same manner as in Example 1 except that trioctylphosphine [TOP] was used.

<Ion dissolution test>
In Examples 1-4 and Comparative Examples 1-5, the ion elution test was implemented as follows.

  The semiconductor nanoparticles synthesized in Comparative Examples 1 to 3 were precipitated with acetone as a poor solvent, the solvent was removed by centrifugation, 1 mL of ultrapure water and 1 μM mercaptopropionic acid were added, and the concentration of the semiconductor nanoparticles was 0. . Solubilized to 1 μM. After standing for 1 day, acetone was added again to precipitate water-soluble semiconductor nanoparticles, and the amount of ions eluted from the supernatant was calculated using ICP-AES.

  Semiconductor nanoparticle aggregate in which CdTe / ZnS is present in the silica matrix produced in Comparative Example 4, semiconductor nanoparticles in which CdTe / ZnS and dodecylamine are swollen in the polystyrene matrix produced in Comparative Example 5, and Example 1 Each of the matrix-coated aggregates produced in 4 was allowed to stand for 1 day, centrifuged, and the amount of ions eluted from the supernatant was measured using ICP-AES.

  These results are shown in Table 1.

  As is clear from the results shown in Table 1, it can be seen that the solvent resistance of the matrix-coated assemblies of Examples 1 to 4 is superior to that of the comparative example.

Claims (7)

A semiconductor nanoparticle assembly containing semiconductor nanoparticles having a core / shell structure, and a surfactant bonded thereto;
A matrix-covered aggregate comprising a silica matrix covering the semiconductor nanoparticle aggregate to which the surfactant is bound.   The matrix-coated assembly according to claim 1, wherein the surfactant is a higher amine.   3. The matrix-coated assembly according to claim 1, wherein the core part of the core / shell structure is indium phosphide [InP], cadmium selenide [CdSe], or cadmium telluride [CdTe]. Obtained by water-solubilizing a semiconductor nanoparticle aggregate containing semiconductor nanoparticles having a core / shell structure using an amount of a surfactant that exceeds the limit amount dissolved in water; and step (X). The periphery of the water-soluble semiconductor nanoparticle aggregate to be coated with a silica matrix (Y)
A process for producing a matrix-covered aggregate comprising the steps of:   The production method according to claim 4, wherein the surfactant is a higher amine. The silica matrix is obtained by adding ethanol, ammonia [NH ₃ ] and tetraethoxysilane [TEOS] in this order to the water-soluble semiconductor nanoparticle aggregate obtained in the step (X). 5. The production method according to 5.   The manufacturing method according to any one of claims 4 to 6, wherein the core portion of the core / shell structure is indium phosphide [InP], cadmium selenide [CdSe], or cadmium telluride [CdTe].