WO2011158531A1 - Semiconductor nanoparticle aggregate - Google Patents

Semiconductor nanoparticle aggregate Download PDF

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Publication number
WO2011158531A1
WO2011158531A1 PCT/JP2011/054296 JP2011054296W WO2011158531A1 WO 2011158531 A1 WO2011158531 A1 WO 2011158531A1 JP 2011054296 W JP2011054296 W JP 2011054296W WO 2011158531 A1 WO2011158531 A1 WO 2011158531A1
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semiconductor
core
aggregate
semiconductor nanoparticle
shell
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PCT/JP2011/054296
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French (fr)
Japanese (ja)
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優 高橋
秀樹 星野
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コニカミノルタエムジー株式会社
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Publication of WO2011158531A1 publication Critical patent/WO2011158531A1/en

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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B25/00—Phosphorus; Compounds thereof
    • C01B25/08—Other phosphides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B19/00—Selenium; Tellurium; Compounds thereof
    • C01B19/007—Tellurides or selenides of metals
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/02—Silicon
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G11/00—Compounds of cadmium
    • C01G11/02—Sulfides
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G15/00—Compounds of gallium, indium or thallium
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G9/00—Compounds of zinc
    • C01G9/08—Sulfides
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    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/02—Use of particular materials as binders, particle coatings or suspension media therefor
    • C09K11/025—Use of particular materials as binders, particle coatings or suspension media therefor non-luminescent particle coatings or suspension media
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/56—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing sulfur
    • C09K11/562—Chalcogenides
    • C09K11/565—Chalcogenides with zinc cadmium
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/59—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing silicon
    • C09K11/592—Chalcogenides
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/62—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing gallium, indium or thallium
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/88—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing selenium, tellurium or unspecified chalcogen elements
    • C09K11/881—Chalcogenides
    • C09K11/883—Chalcogenides with zinc or cadmium
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer
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    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/80—Particles consisting of a mixture of two or more inorganic phases
    • C01P2004/82—Particles consisting of a mixture of two or more inorganic phases two phases having the same anion, e.g. both oxidic phases
    • C01P2004/84—Particles consisting of a mixture of two or more inorganic phases two phases having the same anion, e.g. both oxidic phases one phase coated with the other
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/40—Electric properties

Definitions

  • the present invention relates to a semiconductor nanoparticle assembly with high emission luminance.
  • III-V group semiconductor nanoparticles As semiconductor nanoparticles emitting fluorescence, II-VI group and III-V group semiconductor nanoparticles are widely known. If these semiconductor nanoparticles are used as a fluorescent diagnostic agent, the brightness per particle is still insufficient.
  • the brightness of the particles is much lower with the core semiconductor nanoparticles alone than with the semiconductor nanoparticles having a core / shell structure.
  • a semiconductor material having a wider band gap than the core particle as the shell quantum wells are formed, and the luminance is significantly improved by the quantum confinement effect.
  • a method of increasing the brightness a method of increasing the brightness per particle by integrating the core / shell semiconductor nanoparticles can be considered.
  • concentration quenching is considered to be caused by the fact that electron transfer occurs when the core / shell particles come into contact with each other and the quantum confinement effect is lowered.
  • Patent Document 1 discloses a reverse micelle method and a sol-gel method using a mixture of an organoalkoxysilane and an alkoxide having an organic functional group having a good adsorptivity to semiconductor nanoparticles at the end of a molecule as a glass precursor.
  • a glass phosphor having semiconductor nanoparticles dispersed and fixed therein is disclosed.
  • a decrease in luminous efficiency is observed due to the influence of the reaction in the sol-gel method.
  • the hydrolysis product of an organic alkoxysilane and an alkoxide is included, there exists a problem that the distance between semiconductor nanoparticles becomes long and a semiconductor particle cannot be collected so much concentration.
  • the present invention has been made in view of the above-described problems and situations, and a solution to the problem is a semiconductor nanoparticle aggregate having high emission luminance that does not quench the concentration even when semiconductor nanoparticles emitting fluorescence are densely integrated. Is to provide.
  • a semiconductor nanoparticle aggregate comprising a semiconductor nanoparticle having a core / shell structure, wherein the semiconductor nanoparticle aggregate is formed by re-shelling an aggregate of semiconductor nanoparticles.
  • the material constituting the core part of the semiconductor nanoparticles having the core / shell structure is selected from the group consisting of indium phosphide (InP), silicon (Si), cadmium selenide (CdSe), and cadmium telluride (CdTe). 4.
  • a poor solvent is added to form an aggregate of core / shell semiconductor nanoparticles.
  • the aggregate does not have the brightness corresponding to the number of core / shell semiconductor nanoparticles due to the concentration quenching as it is.
  • the light emission luminance is about 40% of the original light emission luminance of each core / shell semiconductor nanoparticle constituting the aggregate.
  • the semiconductor nanoparticle assembly of the present invention is a semiconductor nanoparticle assembly containing semiconductor nanoparticles having a core / shell structure, and is formed by re-shelling an aggregate of the semiconductor nanoparticles. And This feature is a technical feature common to the inventions according to claims 1 to 5.
  • the material constituting the shell part of the semiconductor nanoparticles having the core / shell structure and the material for re-shelling are the same compound, or It is preferable to contain the same compound.
  • material which constitutes the shell portion of the semiconductor nanoparticles having the core / shell structure is preferably a zinc sulfide (ZnS) or silicon dioxide (SiO 2).
  • the material which comprises the core part of the semiconductor nanoparticle which has the said core / shell structure consists of indium phosphide (InP), silicon (Si), cadmium selenide (CdSe), and cadmium telluride (CdTe). It is preferably a simple substance or a compound selected from
  • the average particle diameter of the semiconductor nanoparticle aggregate is in the range of 50 to 500 nm.
  • ⁇ is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.
  • the semiconductor nanoparticle assembly of the present invention is a semiconductor nanoparticle assembly containing semiconductor nanoparticles having a core / shell structure, and is formed by re-shelling an aggregate of the semiconductor nanoparticles.
  • the “semiconductor nanoparticle having a core / shell structure” is a particle having a nanosize (1 to 1000 nm) particle size containing a semiconductor forming material (material) described later, ) And a shell part (covering part) covering the same.
  • aggregate refers to an aggregate in which a plurality of semiconductor nanoparticles are in contact with each other.
  • Aggregate refers to particles obtained by shelling the aggregate.
  • Re-shelling refers to shelling a core / shell structure semiconductor nanoparticle aggregate.
  • the peak of pores derived between the particles of the semiconductor nanoparticles is within the range of 5 to 50 nm in the aggregate.
  • the aggregate is characterized in that no pore peak is observed at 5 to 50 nm, but only a pore peak (100 nm or more) derived between the aggregates.
  • pores are found in the aggregate and it is very porous.
  • pores such as micropores and mesopores are not seen, and the aggregate surface is coated. it is conceivable that.
  • the pore size distribution measurement using N 2 molecules can be performed using BELSORP-mini gas adsorption instrument of BEL.
  • the adsorption / desorption curve is measured at 77 k, and the pore size distribution can be calculated by the BJH (Barrett, Joyner, and Halenda) method using the adsorption curve.
  • the TEM image can be observed using, for example, Hitachi H-9000NA (300 kV).
  • the aggregate of semiconductor nanoparticles according to the present invention can be formed by using a poor solvent that hardly dissolves the semiconductor nanoparticles and their materials in the semiconductor nanoparticle formation process or the dispersion process after the formation.
  • the poor solvent for example, alcohols (methanol, ethanol, propanol, etc.) and ketones (acetone, methyl ethyl ketone, etc.) can be used.
  • the average particle size of the semiconductor nanoparticle aggregate is preferably within the range of 5 to 1000 nm, and more preferably within the range of 50 to 500 nm.
  • the particle size (volume average particle size) of the semiconductor nanoparticles having a core / shell structure and the semiconductor nanoparticle aggregate is measured by a particle size measuring device by a dynamic light scattering method (Malvern Instruments, Zetasizer Nano S). It was determined by measuring the particle size distribution immediately after the production of semiconductor nanoparticles or aggregates (before aggregation). The average particle size (volume average particle size) was the particle size at the peak (center) position of the particle size distribution.
  • the elemental ratio of semiconductor nanoparticles is measured using a sequential high-frequency plasma emission analyzer (ICPS-7500, manufactured by Shimadzu Corporation). Thereafter, the element ratio of the re-shelled semiconductor nanoparticle assembly is measured by the high-frequency plasma emission analyzer (ICP-AES) to calculate the concentration used for the re-shelling. Since the densities of the semiconductor nanoparticles and the re-shelling compound are known, it is possible to estimate the number of inclusions together with the average particle diameter calculated by the dynamic light scattering method.
  • ICPS-7500 sequential high-frequency plasma emission analyzer
  • ICP-AES high-frequency plasma emission analyzer
  • the number of semiconductor nanoparticles having a core / shell structure contained in the semiconductor nanoparticle aggregate is preferably as large as possible.
  • the number of inclusions is preferably 800 or more.
  • Core part forming material examples include semiconductors such as Si, Ge, InN, InP, GaAs, AlSe, CdSe, AlAs, GaP, ZnTe, CdTe, and InAs. Or the raw material which forms these can be used.
  • InP, Si, CdTe, and CdSe are particularly preferably used.
  • the average particle size of the core portion (“core particle”) according to the present invention is preferably 0.5 to 15 nm.
  • II-VI group, III-V group, and IV group inorganic semiconductors can be used as a material for forming the shell portion according to the present invention.
  • a semiconductor having a larger band gap than each core-forming inorganic material such as Si, Ge, InN, InP, GaAs, AlSe, CdSe, AlAs, GaP, ZnTe, CdTe, InAs, etc. Is preferred.
  • ZnS is applied to InP, CdTe, and CdSe, and SiO 2 is applied to Si as a shell.
  • the shell portion according to the present invention may not completely cover the entire surface of the core particle as long as the core particle is not partially exposed to cause a harmful effect.
  • the average particle size of the core / shell structure semiconductor nanoparticle according to the present invention is preferably 1 to 20 nm.
  • Re-shelling material As a material used for reselling the aggregate of semiconductor nanoparticles, the same material as the shell portion forming material can be used.
  • Si, Ge, InN, InP, GaAs, AlSe, CdSe, AlAs, GaP, ZnTe, CdTe, and InAs are preferable.
  • a shell having the same composition as the shell part of the core / shell structure semiconductor nanoparticles is applied (if the core / shell structure semiconductor nanoparticles are InP / ZnS, CdTe / ZnS, and CdSe / ZnS, ZnS In the case of Si / SiO 2 , SiO 2 ).
  • the shell thickness at the time of re-shelling can be easily controlled by changing the amount added at the time of re-shelling.
  • the shell thickness at the time of re-shelling is a value obtained by subtracting the average particle size of the semiconductor nanoparticle aggregate from the average particle size of the semiconductor nanoparticle aggregate, and the thickness is preferably 2 to 200 nm.
  • the thickness is preferably in the range of ⁇ 20 nm.
  • Method for producing semiconductor nanoparticles As a method for producing semiconductor nanoparticles according to the present invention, a liquid phase method or a gas phase method can be employed.
  • liquid phase method examples include a precipitation method, a coprecipitation method, a sol-gel method, a uniform precipitation method, and a reduction method.
  • the reverse micelle method, the supercritical hydrothermal synthesis method, and the like are also excellent methods for producing nanoparticles (for example, JP 2002-322468, JP 2005-239775, JP 10-310770 A). No., JP 2000-104058 A, etc.).
  • the semiconductor precursor according to the present invention is a compound containing an element used as the semiconductor material.
  • the semiconductor precursor includes SiCl 4 .
  • 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 for reducing the semiconductor precursor various conventionally known reducing agents can be selected and used according to the reaction conditions.
  • lithium aluminum hydride (LiAlH 4 ) is preferable because of its reducing power.
  • solvents can be used as the solvent for dispersing the semiconductor precursor.
  • Alcohols such as ethyl alcohol, sec-butyl alcohol and t-butyl alcohol, and hydrocarbon solvents such as toluene, decane and hexane are used. It is preferable to use it.
  • a hydrophobic solvent such as toluene is particularly preferable as the dispersion solvent.
  • ⁇ 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.
  • special care must be taken.
  • 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.
  • the opposing raw material semiconductor is evaporated by the first high temperature plasma generated between the electrodes, and in the second high temperature plasma generated by electrodeless discharge in a reduced pressure atmosphere.
  • a method of separating and removing nanoparticles from an anode made of a raw material semiconductor by electrochemical etching for example, see Japanese Patent Application Laid-Open No. 2003-515459).
  • laser ablation for example, see JP-A-2004-356163
  • high-speed sputtering method for example, see JP-A-2004-296781
  • a method of synthesizing a powder containing particles by reacting a raw material gas in a gas phase in a low pressure state is also preferably used.
  • the semiconductor nanoparticle 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 generated from the fluorescent semiconductor fine particles according to the excitation light, fluorescence dynamic imaging of the target (tracking) substance can be performed.
  • the biological material labeling agent according to the present invention can be used for a bioimaging method (technical means for visualizing biological molecules constituting the biological material and dynamic phenomena thereof).
  • hydrophilic treatment method for example, there is a method in which a surface modifying agent is chemically and / or physically bonded to the surface of the semiconductor nanoparticle assembly after removing the lipophilic group on the surface with pyridine or the like.
  • a surface modifying agent for example, those having a carboxyl group / amino group as a hydrophilic group are preferably used, and specific examples include mercaptopropionic acid, mercaptoundecanoic acid, aminopropanethiol and the like.
  • 10 ⁇ 5 g of Ge / GeO 2 type nanoparticles are dispersed in 10 ml of pure water in which 0.2 g of mercaptoundecanoic acid is dissolved, and stirred at 40 ° C. for 10 minutes to treat the surface of the shell.
  • the surface of the shell of the inorganic nanoparticles can be modified with a carboxyl group.
  • the biological material labeling agent according to the present invention is obtained by binding the above-described hydrophilic nanoparticle aggregate, the molecular labeling material, and an organic molecule.
  • the biological substance labeling agent according to the present invention can label a biological substance by specifically binding and / or reacting with the target biological substance.
  • Examples of the molecular labeling substance include nucleotide chains, antibodies, antigens, and cyclodextrins.
  • a hydrophilic semiconductor nanoparticle aggregate and a molecular labeling substance are bound by an organic molecule.
  • the organic molecule is not particularly limited as long as it is an organic molecule that can bind the semiconductor nanoparticle aggregate and the molecular labeling substance.
  • the form of the bond is not particularly limited, and examples thereof include covalent bond, ionic bond, hydrogen bond, 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.
  • the semiconductor nanoparticle aggregate is hydrophilized with mercaptoundecanoic acid
  • avidin and biotin can be used as organic molecules.
  • the carboxyl group of the nanoparticles subjected to hydrophilic treatment is preferably covalently bonded to avidin, and avidin further selectively binds to biotin, and biotin further binds to the biological material labeling agent to become a biological material labeling agent.
  • InP core particles were synthesized by the following heated solution method.
  • the InP core particles thus obtained were particles having a maximum emission wavelength at 630 nm.
  • the InP / ZnS core / shell semiconductor nanoparticles thus obtained were particles having a maximum emission wavelength at 630 nm, similar to the InP core particles.
  • the semiconductor nanoparticle aggregate-containing dispersion is centrifuged and washed several times with ethanol. Octadecene was added to the washed precipitate, and the solvent was replaced with octadecene. At that time, re-dispersion of the aggregate did not occur and the particle size of the aggregate was maintained.
  • the temperature was raised from 80 ° C. to 230 ° C. and reacted for 30 minutes to re-shell, thereby obtaining a semiconductor nanoparticle aggregate.
  • ZnS was added in an amount 10 times the amount of InP or InP / ZnS core particles.
  • Si / SiO 2 core / shell semiconductor nanoparticles were obtained by treating amorphous Si (manufactured by Sigma-Aldrich) with an HNO 3 / HF solution.
  • Si core particles were particles having a maximum emission wavelength at 630 nm.
  • Si or Si / SiO 2 aggregate is crystallized as HF as CaF by adding CaCO 3 to the Si / SiO 2 core / shell or Si core semiconductor nanoparticle dispersion, the CaF is removed by filtration. It is obtained by adding acetone, which is a poor solvent.
  • TEOS tetraethoxysilane
  • CdSe / ZnS core / shell semiconductor nanoparticle synthesis was performed 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.
  • the semiconductor nanoparticle aggregate-containing dispersion is centrifuged and washed several times with ethanol. Octadecene was added to the washed precipitate, and the solvent was replaced with octadecene. At that time, re-dispersion of the aggregate did not occur and the particle size of the aggregate was maintained.
  • This octadecene-substituted aggregate solution is transferred to a three-necked flask, heated to 80 ° C., zinc stearate + sulfur is added, the temperature is raised from 80 ° C. to 230 ° C., and reacted for 30 minutes to re-shell. A nanoparticle assembly was obtained. The re-shelling when the aggregates were aggregated added ZnS in a 10-fold molar amount of CdSe or CdSe / ZnS core particles.
  • Example 12 (Examples 12, 13, and 14) (Synthesis of CdTe core particles and CdTe / ZnS core / shell semiconductor nanoparticles) CdTe core particles and CdTe / ZnS core / shell semiconductor nanoparticles were synthesized according to Example 1 of JP-A-2005-281019.
  • the CdTe core particles were synthesized according to the method according to Hemy, Volume 100, page 1772 (1996).
  • the CdTe core particles thus obtained were particles having a maximum emission wavelength at 640 nm.
  • the semiconductor nanoparticle aggregate-containing dispersion is centrifuged and washed several times with ethanol. Octadecene was added to the washed precipitate, and the solvent was replaced with octadecene. At that time, re-dispersion of the aggregate did not occur and the particle size of the aggregate was maintained.
  • Zn / S 1 and 10 times the molar amount of ZnS as CdTe or CdTe / ZnS core particles.
  • ZnS is added in an amount 10 times the amount of CdTe or CdTe / ZnS core particles.
  • Example 4 According to Example 1 described in Japanese Patent Application Laid-Open No. 2005-281019, a semiconductor nanoparticle aggregate in which InP / ZnS, CdSe / ZnS, and CdTe / ZnS exist in the silica matrix was produced.
  • the surfactant bis (2-ethylhexyl) sulfosuccinate sodium (required for forming reverse micelle (reverse microemulsion) in 25 ml of isooctane (2,2,4-trimethylpentane) as a hydrophobic organic solvent ( (Aerosol OT) (also referred to as “AOT”) 1.1115 g was dissolved and then 0.74 ml of water and the above water-soluble InP / ZnS, CdSe / ZnS, CdTe / ZnS were mixed while stirring the solution. 0.3 ml of the core / shell semiconductor nanoparticle solution was added and dissolved.
  • AOT hydrophobic organic solvent
  • TEOS tetraethoxysilane
  • APS aminopropyltrimethoxysilane
  • the dispersion was stirred for 2 days to obtain a semiconductor nanoparticle aggregate in which InP / ZnS, CdSe / ZnS, and CdTe / ZnS were present in the silica matrix, respectively.
  • Table 1 summarizes the contents of the various semiconductor nanoparticle assemblies obtained above and the results of luminance measurement.
  • the luminance measurement uses a 146 nm vacuum ultraviolet lamp (USHIO Inc.) as a light source, sets a sample in a vacuum chamber, and irradiates excitation light from a certain distance at a vacuum degree of 1.33 ⁇ 10 Pa. Measured with The luminance value is shown as a relative value when the luminance of the InP particle assembly of Example 1 is 1000.
  • USHIO Inc. 146 nm vacuum ultraviolet lamp
  • the particle size (volume average particle size) of the semiconductor nanoparticles and the semiconductor nanoparticle aggregate is determined by using a particle size measuring device (Malvern Instruments, Zetasizer Nano S) by dynamic light scattering method. It was determined by measuring the particle size distribution immediately after production (before aggregation). The average particle size (volume average particle size) was the particle size at the peak (center) position of the particle size distribution.
  • a particle size measuring device Malvern Instruments, Zetasizer Nano S
  • the elemental ratio of the semiconductor nanoparticles was measured using a sequential type high frequency plasma emission analyzer (ICPS-7500, manufactured by Shimadzu Corporation). Thereafter, the element ratio of the re-shelled semiconductor nanoparticle assembly was measured with the high-frequency plasma emission analyzer (ICP-AES) to calculate the concentration used for re-shelling. Since the densities of the semiconductor nanoparticles and the re-shelling compound are known, the inclusion number was estimated together with the average particle diameter calculated by the dynamic light scattering method.
  • ICPS-7500 sequential type high frequency plasma emission analyzer
  • ICP-AES high-frequency plasma emission analyzer
  • the emission luminance of the semiconductor nanoparticle aggregate formed by re-shelling the aggregate of semiconductor nanoparticles of the present invention is superior to that of the comparative example. I understand.

Abstract

Disclosed is a semiconductor nanoparticle aggregate with a high emission luminance and without concentration quenching even when semiconductor nanoparticles that emit fluorescent light are densely accumulated. The semiconductor nanoparticle aggregate contains semiconductor nanoparticles with a core/shell structure and is characterized by being formed by re-shelling semiconductor nanoparticle agglomerates.

Description

半導体ナノ粒子集積体Semiconductor nanoparticle assembly
　本発明は、発光輝度の高い半導体ナノ粒子集積体に関する。 The present invention relates to a semiconductor nanoparticle assembly with high emission luminance.
　標識剤として蛍光発光する半導体ナノ粒子を用いる場合、一粒子当たりの輝度が大きいほど感度が高くなることから、一粒子当たりの輝度のより高い粒子が望まれている。 When semiconductor nanoparticles that fluoresce as a labeling agent are used, the higher the luminance per particle, the higher the sensitivity. Therefore, particles with higher luminance per particle are desired.
　蛍光発光する半導体ナノ粒子としては、II－VI族、及びIII－Ｖ族の半導体ナノ粒子が広く知られている。これらの半導体ナノ粒子を蛍光診断薬として使用するとなると、一粒子当たりの輝度がまだまだ足りないというのが現状である。 As semiconductor nanoparticles emitting fluorescence, II-VI group and III-V group semiconductor nanoparticles are widely known. If these semiconductor nanoparticles are used as a fluorescent diagnostic agent, the brightness per particle is still insufficient.
　一方、一般的に、コア／シェル構造を有する半導体ナノ粒子に比べ、コア半導体ナノ粒子だけでは粒子の輝度は非常に低い。コア粒子よりもバンドギャップの広い半導体材料をシェルとして用いることにより、量子井戸が形成され量子閉じ込め効果により輝度は著しく向上する。 On the other hand, in general, the brightness of the particles is much lower with the core semiconductor nanoparticles alone than with the semiconductor nanoparticles having a core / shell structure. By using a semiconductor material having a wider band gap than the core particle as the shell, quantum wells are formed, and the luminance is significantly improved by the quantum confinement effect.
　したがって、高輝度化する方法として、コア／シェル半導体ナノ粒子を集積させ一粒子当たりの輝度を上げる方法が考えられる。 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.
　しかし、高密度で半導体ナノ粒子を集積させると、粒子間の距離が近くなりすぎてしまい濃度消光が起こる。ここでの濃度消光はコア／シェル粒子が接触することにより電子移送が起こり、量子閉じ込め効果が低くなることが原因であると考えられる。 However, when semiconductor nanoparticles are accumulated at high density, the distance between the particles becomes too close and concentration quenching occurs. The concentration quenching here is considered to be caused by the fact that electron transfer occurs when the core / shell particles come into contact with each other and the quantum confinement effect is lowered.
　また、一方、このような半導体ナノ粒子については、水溶液中で合成する方法と非水溶液中で合成する方法が開発されている。しかしながら、溶液中で合成した半導体ナノ粒子は、合成した直後から、次第に粒子の凝集等が起こって発光特性が劣化し、また、特に非水溶液中で合成したナノ粒子は、水分に弱く、微量の水分の共存によって蛍光が急速に衰え、さらに、ナノ粒子の溶液のままでは材料として工学的に応用しにくいという問題があった。そのため、半導体ナノ粒子を透明なガラス等のマトリックス中に分散固定する形で閉じ込め、種々の環境下で長期にわたって高輝度発光特性を示す工学的応用に適した固体材料とする技術が提案されている。 On the other hand, a method of synthesizing such semiconductor nanoparticles in an aqueous solution and a method of synthesizing in a non-aqueous solution have been developed. However, the semiconductor nanoparticles synthesized in the solution are deteriorated in light emission characteristics immediately after the synthesis due to the aggregation of the particles, and the nanoparticles synthesized in the non-aqueous solution are particularly vulnerable to moisture and have a trace amount. Due to the coexistence of moisture, the fluorescence rapidly decays, and further, there is a problem that it is difficult to apply the material as a material if it is in a solution of nanoparticles. For this reason, a technology has been proposed in which semiconductor nanoparticles are confined in a form of being dispersed and fixed in a matrix such as transparent glass, and a solid material suitable for engineering applications exhibiting high-luminance emission characteristics over a long period of time in various environments. .
　例えば、特許文献１には、逆ミセル法と、ガラスの前駆体として分子の末端に半導体ナノ粒子への吸着性が良い有機官能基を有する有機アルコキシシランとアルコキシドの混合物を用いたゾル－ゲル法とを組み合わせることにより、半導体ナノ粒子を内部に分散固定したガラス蛍光体が開示されている。しかしながら、ゾル－ゲル法における反応の影響により発光効率の低下が見られる。また、有機アルコキシシラン及びアルコキシドの加水分解生成物を含むため、半導体ナノ粒子間の距離が長くなってしまい、それほど高濃度に半導体粒子を集めることはできないという問題がある。 For example, Patent Document 1 discloses a reverse micelle method and a sol-gel method using a mixture of an organoalkoxysilane and an alkoxide having an organic functional group having a good adsorptivity to semiconductor nanoparticles at the end of a molecule as a glass precursor. In combination with the above, a glass phosphor having semiconductor nanoparticles dispersed and fixed therein is disclosed. However, a decrease in luminous efficiency is observed due to the influence of the reaction in the sol-gel method. Moreover, since the hydrolysis product of an organic alkoxysilane and an alkoxide is included, there exists a problem that the distance between semiconductor nanoparticles becomes long and a semiconductor particle cannot be collected so much concentration.
特開２００５－２８１０１９号公報JP 2005-281019 A
　本発明は、上記問題・状況にかんがみてなされたものであり、その解決課題は、蛍光発光する半導体ナノ粒子を高密度に集積させても濃度消光せず、発光輝度の高い半導体ナノ粒子集積体を提供することである。 The present invention has been made in view of the above-described problems and situations, and a solution to the problem is a semiconductor nanoparticle aggregate having high emission luminance that does not quench the concentration even when semiconductor nanoparticles emitting fluorescence are densely integrated. Is to provide.
　本発明に係る上記課題は、以下の手段により解決される。 The above-mentioned problem according to the present invention is solved by the following means.
　１．コア／シェル構造を持つ半導体ナノ粒子を含有する半導体ナノ粒子集積体であって、半導体ナノ粒子の凝集体を再シェリングすることにより形成されたことを特徴とする半導体ナノ粒子集積体。 1. A semiconductor nanoparticle aggregate comprising a semiconductor nanoparticle having a core / shell structure, wherein the semiconductor nanoparticle aggregate is formed by re-shelling an aggregate of semiconductor nanoparticles.
　２．前記コア／シェル構造を持つ半導体ナノ粒子のシェル部を構成する素材と再シェリング用の素材が、同一の化合物であること又は当該同一の化合物を含有することを特徴とする前記第１項に記載の半導体ナノ粒子集積体。 2. 2. The material according to item 1, wherein the material constituting the shell part of the semiconductor nanoparticle having the core / shell structure and the material for re-shelling are the same compound or contain the same compound. Semiconductor nanoparticle assembly.
　３．前記コア／シェル構造を持つ半導体ナノ粒子のシェル部を構成する素材が、硫化亜鉛（ＺｎＳ）又は二酸化珪素（ＳｉＯ2）であることを特徴とする前記第１項又は第２項に記載の半導体ナノ粒子集積体。 3. 3. The semiconductor according to item 1 or 2, wherein a material constituting the shell part of the semiconductor nanoparticles having the core / shell structure is zinc sulfide (ZnS) or silicon dioxide (SiO 2 ). Nanoparticle assembly.
　４．前記コア／シェル構造を持つ半導体ナノ粒子のコア部を構成する素材が、リン化インジウム（ＩｎＰ）、ケイ素（Ｓｉ）、セレン化カドミウム（ＣｄＳｅ）、及びテルル化カドミウム（ＣｄＴｅ）からなる群から選ばれる単体又は化合物であることを特徴とする前記第１項から第３項までのいずれか一項に記載の半導体ナノ粒子集積体。 4. The material constituting the core part of the semiconductor nanoparticles having the core / shell structure is selected from the group consisting of indium phosphide (InP), silicon (Si), cadmium selenide (CdSe), and cadmium telluride (CdTe). 4. The semiconductor nanoparticle assembly according to any one of items 1 to 3, wherein the semiconductor nanoparticle assembly is a simple substance or a compound.
　５．平均粒径が、５０～５００ｎｍの範囲内であることを特徴とする前記第１項から第４項までのいずれか一項に記載の半導体ナノ粒子集積体。 5. The semiconductor nanoparticle assembly according to any one of items 1 to 4, wherein an average particle diameter is in a range of 50 to 500 nm.
　本発明の上記手段により、蛍光発光する半導体ナノ粒子を高密度に集積させても濃度消光せず、発光輝度の高い半導体ナノ粒子集積体を提供することができる。 By the above means of the present invention, it is possible to provide a semiconductor nanoparticle aggregate with high emission brightness without concentration quenching even when semiconductor nanoparticles emitting fluorescent light are integrated at high density.
　本発明では、貧溶媒を加えてコア／シェル半導体ナノ粒子の凝集体を形成させる。当該凝集体は、そのままでは、前記濃度消光を起こしコア／シェル半導体ナノ粒子の個数分の輝度にはならない。凝集体を構成する各コア／シェル半導体ナノ粒子の本来の発光輝度の４割程度の発光輝度となる。 In the present invention, a poor solvent is added to form an aggregate of core / shell semiconductor nanoparticles. The aggregate does not have the brightness corresponding to the number of core / shell semiconductor nanoparticles due to the concentration quenching as it is. The light emission luminance is about 40% of the original light emission luminance of each core / shell semiconductor nanoparticle constituting the aggregate.
　しかし、本発明では、コア／シェル半導体ナノ粒子の凝集体を再シェリングすることにより濃度消光が起こる程度を少なくすることを可能とした。コア／シェル半導体ナノ粒子間で起こっていた電子移送が再シェリングによって妨げられ、再び量子閉じ込め効果が表れたことによると考えられる。 However, in the present invention, it is possible to reduce the degree of concentration quenching by re-shelling the aggregate of core / shell semiconductor nanoparticles. It is considered that the electron transfer that occurred between the core / shell semiconductor nanoparticles was hindered by re-shelling, and the quantum confinement effect appeared again.
　本発明の半導体ナノ粒子集積体は、コア／シェル構造を持つ半導体ナノ粒子を含有する半導体ナノ粒子集積体であって、当該半導体ナノ粒子の凝集体を再シェリングすることにより形成されたことを特徴とする。この特徴は、請求項１から請求項５までの請求項に係る発明に共通する技術的特徴である。 The semiconductor nanoparticle assembly of the present invention is a semiconductor nanoparticle assembly containing semiconductor nanoparticles having a core / shell structure, and is formed by re-shelling an aggregate of the semiconductor nanoparticles. And This feature is a technical feature common to the inventions according to claims 1 to 5.
　本発明の実施態様としては、本発明の効果発現の観点から、前記コア／シェル構造を持つ半導体ナノ粒子のシェル部を構成する素材と再シェリング用の素材が、同一の化合物であること又は当該同一の化合物を含有することが好ましい。また、当該コア／シェル構造を持つ半導体ナノ粒子のシェル部を構成する素材が、硫化亜鉛（ＺｎＳ）又は二酸化珪素（ＳｉＯ2）であることが好ましい。さらに、当該コア／シェル構造を持つ半導体ナノ粒子のコア部を構成する素材が、リン化インジウム（ＩｎＰ）、ケイ素（Ｓｉ）、セレン化カドミウム（ＣｄＳｅ）、及びテルル化カドミウム（ＣｄＴｅ）からなる群から選ばれる単体又は化合物であることが好ましい。 As an embodiment of the present invention, from the viewpoint of manifesting the effects of the present invention, the material constituting the shell part of the semiconductor nanoparticles having the core / shell structure and the material for re-shelling are the same compound, or It is preferable to contain the same compound. Furthermore, material which constitutes the shell portion of the semiconductor nanoparticles having the core / shell structure is preferably a zinc sulfide (ZnS) or silicon dioxide (SiO 2). Furthermore, the material which comprises the core part of the semiconductor nanoparticle which has the said core / shell structure consists of indium phosphide (InP), silicon (Si), cadmium selenide (CdSe), and cadmium telluride (CdTe). It is preferably a simple substance or a compound selected from
　本発明においては、半導体ナノ粒子集積体の平均粒径が、５０～５００ｎｍの範囲内であることが好ましい。 In the present invention, it is preferable that the average particle diameter of the semiconductor nanoparticle aggregate is in the range of 50 to 500 nm.
　以下、本発明とその構成要素、及び本発明を実施するための形態・態様について詳細な説明をする。なお、本願において、「～」は、その前後に記載される数値を下限値及び上限値として含む意味で使用する。 Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In the present application, “˜” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.
　（半導体ナノ粒子集積体）
　本発明の半導体ナノ粒子集積体は、コア／シェル構造を持つ半導体ナノ粒子を含有する半導体ナノ粒子集積体であって、当該半導体ナノ粒子の凝集体を再シェリングすることにより形成されたことを特徴とする。 (Semiconductor nanoparticle assembly)
The semiconductor nanoparticle assembly of the present invention is a semiconductor nanoparticle assembly containing semiconductor nanoparticles having a core / shell structure, and is formed by re-shelling an aggregate of the semiconductor nanoparticles. And
　本願において、「コア／シェル構造を持つ半導体ナノ粒子」とは、後述する半導体形成材料（素材）を含有するナノサイズ（１～１０００ｎｍ）の粒径を有する粒子であって、コア部（芯部）とそれを被覆するシェル部（被覆部）で構成される多重構造を有する粒子をいう。 In the present application, the “semiconductor nanoparticle having a core / shell structure” is a particle having a nanosize (1 to 1000 nm) particle size containing a semiconductor forming material (material) described later, ) And a shell part (covering part) covering the same.
　また、「凝集体」とは、複数の半導体ナノ粒子が相互に接触した状態で集まった集合体をいう。「集積体」とは、当該凝集体をシェリングして得られる粒子のことをいう。「再シェリング」とは、コア／シェル構造半導体ナノ粒子凝集体をシェリングすることをいう。 Also, “aggregate” refers to an aggregate in which a plurality of semiconductor nanoparticles are in contact with each other. “Aggregate” refers to particles obtained by shelling the aggregate. “Re-shelling” refers to shelling a core / shell structure semiconductor nanoparticle aggregate.
　粒子の細孔径分布を下記測定法及び透過型電子顕微鏡像（ＴＥＭ像）観察等により見ると、凝集体では、半導体ナノ粒子の粒子間に由来する細孔のピークが５～５０ｎｍの範囲内に見られるのに対して、集積体では５～５０ｎｍに細孔のピークは見られず、凝集体間に由来する細孔のピーク（１００ｎｍ以上）のみとなることが特徴である。凝集体では凝集体内に細孔が見られ、非常に多孔質になっているが、集積体にするとミクロ孔やメソ孔といった細孔は見られず、凝集体の表面が被覆された粒子であると考えられる。 When the pore size distribution of the particles is observed by the following measurement method and observation with a transmission electron microscope image (TEM image), the peak of pores derived between the particles of the semiconductor nanoparticles is within the range of 5 to 50 nm in the aggregate. In contrast, the aggregate is characterized in that no pore peak is observed at 5 to 50 nm, but only a pore peak (100 nm or more) derived between the aggregates. In the aggregate, pores are found in the aggregate and it is very porous. However, when the aggregate is formed, pores such as micropores and mesopores are not seen, and the aggregate surface is coated. it is conceivable that.
　なお、上記の細孔径分布の測定については、例えば、ＢＥＬ社のＢＥＬＳＯＲＰ－ｍｉｎｉ　ｇａｓ　ａｄｓｏｒｐｔｉｏｎ　ｉｎｓｔｒｕｍｅｎｔを用いて、Ｎ2分子を用いた細孔径分布測定行うことができる。吸脱着曲線は７７ｋで測定を行い、細孔径分布は吸着曲線を用いてＢＪＨ（Ｂａｒｒｅｔｔ，Ｊｏｙｎｅｒ，ａｎｄＨａｌｅｎｄａ）法により計算することができる。なお、ＴＥＭ像の観察は、例えば、日立Ｈ－９０００ＮＡ（３００ｋＶ）を用いて行うことができる。 As for the measurement of the above pore size distribution, for example, the pore size distribution measurement using N 2 molecules can be performed using BELSORP-mini gas adsorption instrument of BEL. The adsorption / desorption curve is measured at 77 k, and the pore size distribution can be calculated by the BJH (Barrett, Joyner, and Halenda) method using the adsorption curve. The TEM image can be observed using, for example, Hitachi H-9000NA (300 kV).
　本発明に係る半導体ナノ粒子の凝集体は、半導体ナノ粒子形成過程、又は形成後の分散過程において、半導体ナノ粒子及びその材料を殆ど溶解しない貧溶媒を使用することにより形成することができる。 The aggregate of semiconductor nanoparticles according to the present invention can be formed by using a poor solvent that hardly dissolves the semiconductor nanoparticles and their materials in the semiconductor nanoparticle formation process or the dispersion process after the formation.
　ここで、貧溶媒としては、例えば、アルコール類（メタノール、エタノール、プロパノール等）、ケトン類（アセトン、メチルエチルケトン等）を用いることができる。 Here, as the poor solvent, for example, alcohols (methanol, ethanol, propanol, etc.) and ketones (acetone, methyl ethyl ketone, etc.) can be used.
　本発明において、半導体ナノ粒子集積体の平均粒径は、５～１０００ｎｍの範囲内であることが好ましく、さらに５０～５００ｎｍの範囲内であることが好ましい。 In the present invention, the average particle size of the semiconductor nanoparticle aggregate is preferably within the range of 5 to 1000 nm, and more preferably within the range of 50 to 500 nm.
　本願において、コア／シェル構造を持つ半導体ナノ粒子及び半導体ナノ粒子集積体の粒径（体積平均粒径）は、動的光散乱法による粒径測定装置（Ｍａｌｖｅｒｎ　Ｉｎｓｔｒｕｍｅｎｔｓ社製、Ｚｅｔａｓｉｚｅｒ　Ｎａｎｏ　Ｓ）を用いて、半導体ナノ粒子又は集積体作製直後（凝集前）の粒径分布を測定することにより求めた。なお、平均粒径（体積平均粒径）は、粒径分布のピーク（中心）位置の粒径とした。 In the present application, the particle size (volume average particle size) of the semiconductor nanoparticles having a core / shell structure and the semiconductor nanoparticle aggregate is measured by a particle size measuring device by a dynamic light scattering method (Malvern Instruments, Zetasizer Nano S). It was determined by measuring the particle size distribution immediately after the production of semiconductor nanoparticles or aggregates (before aggregation). The average particle size (volume average particle size) was the particle size at the peak (center) position of the particle size distribution.
　また、半導体ナノ粒子の内包数の計算は以下のようにして行った。 Moreover, the calculation of the number of semiconductor nanoparticles included was performed as follows.
　まず、半導体ナノ粒子の元素比を、シーケンシャル形高周波プラズマ発光分析装置（ＩＣＰＳ－７５００　島津製作所製）を用いて計測する。その後、再シェリングされた半導体ナノ粒子集積体の元素比を上記高周波プラズマ発光分析装置（ＩＣＰ－ＡＥＳ）で計測することにより、再シェリングに用いられた濃度を計算する。半導体ナノ粒子、再シェリング化合物の密度は既知であるので、上記動的光散乱法で計算した平均粒径と合わせて内包数を見積もることが可能である。 First, the elemental ratio of semiconductor nanoparticles is measured using a sequential high-frequency plasma emission analyzer (ICPS-7500, manufactured by Shimadzu Corporation). Thereafter, the element ratio of the re-shelled semiconductor nanoparticle assembly is measured by the high-frequency plasma emission analyzer (ICP-AES) to calculate the concentration used for the re-shelling. Since the densities of the semiconductor nanoparticles and the re-shelling compound are known, it is possible to estimate the number of inclusions together with the average particle diameter calculated by the dynamic light scattering method.
　半導体ナノ粒子集積体の粒径を一定にした場合、当該半導体ナノ粒子集積体に含まれるコア／シェル構造を持つ半導体ナノ粒子の数（内包数）は、多ければ多いほど好ましい。 When the particle size of the semiconductor nanoparticle aggregate is constant, the number of semiconductor nanoparticles having a core / shell structure contained in the semiconductor nanoparticle aggregate (the number of inclusions) is preferably as large as possible.
　例えば、粒径が１００ｎｍの半導体ナノ粒子集積体では、内包数が８００以上であることが好ましい。 For example, in a semiconductor nanoparticle assembly having a particle size of 100 nm, the number of inclusions is preferably 800 or more.
　（コア部形成素材）
　本発明に係るコア部（「コア粒子」ともいう。）を形成するための素材としては、Ｓｉ、Ｇｅ、ＩｎＮ、ＩｎＰ、ＧａＡｓ、ＡｌＳｅ、ＣｄＳｅ、ＡｌＡｓ、ＧａＰ、ＺｎＴｅ、ＣｄＴｅ、ＩｎＡｓなどの半導体又はこれらを形成する原料を用いることができる。 (Core part forming material)
Examples of the material for forming the core portion (also referred to as “core particle”) according to the present invention include semiconductors such as Si, Ge, InN, InP, GaAs, AlSe, CdSe, AlAs, GaP, ZnTe, CdTe, and InAs. Or the raw material which forms these can be used.
　本発明においては、特に、ＩｎＰ、Ｓｉ、ＣｄＴｅ、ＣｄＳｅがより好ましく用いられる。 In the present invention, InP, Si, CdTe, and CdSe are particularly preferably used.
　本発明に係るコア部（「コア粒子」）の平均粒径に関しては、０．５～１５ｎｍであることが好ましい。 The average particle size of the core portion (“core particle”) according to the present invention is preferably 0.5 to 15 nm.
　（シェル部形成素材）
　本発明に係るシェル部を形成するための素材としては、II－VI族、III－Ｖ族、IV族の無機半導体を用いることができる。例えば、Ｓｉ、Ｇｅ、ＩｎＮ、ＩｎＰ、ＧａＡｓ、ＡｌＳｅ、ＣｄＳｅ、ＡｌＡｓ、ＧａＰ、ＺｎＴｅ、ＣｄＴｅ、ＩｎＡｓなどの各コア形成無機材料よりバンドギャップが大きく、毒性を有さない半導体又はこれらを形成する原料が好ましい。 (Shell forming material)
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, a semiconductor having a larger band gap than each core-forming inorganic material such as Si, Ge, InN, InP, GaAs, AlSe, CdSe, AlAs, GaP, ZnTe, CdTe, InAs, etc. Is preferred.
　より好ましくは、ＩｎＰ、ＣｄＴｅ、及びＣｄＳｅにはＺｎＳが、ＳｉにはＳｉＯ2がシェルとして適用される。 More preferably, ZnS is applied to InP, CdTe, and CdSe, and SiO 2 is applied to Si as a shell.
　なお、本発明に係るシェル部は、コア粒子が部分的に露出して弊害を生じない限り、コア粒子の全表面を完全に被覆するものでなくてもよい。 It should be noted that the shell portion according to the present invention may not completely cover the entire surface of the core particle as long as the core particle is not partially exposed to cause a harmful effect.
　本発明に係るコア／シェル構造半導体ナノ体粒子の平均粒径は、１～２０ｎｍであることが好ましい。 The average particle size of the core / shell structure semiconductor nanoparticle according to the present invention is preferably 1 to 20 nm.
　（再シェリング用素材）
　本発明において、半導体ナノ粒子の凝集体を再シェリングするために用いる素材としては、上記シェル部形成素材と同様の素材を用いることができる。 (Re-shelling material)
In the present invention, as a material used for reselling the aggregate of semiconductor nanoparticles, the same material as the shell portion forming material can be used.
　例えば、Ｓｉ、Ｇｅ、ＩｎＮ、ＩｎＰ、ＧａＡｓ、ＡｌＳｅ、ＣｄＳｅ、ＡｌＡｓ、ＧａＰ、ＺｎＴｅ、ＣｄＴｅ、ＩｎＡｓが好ましい。 For example, Si, Ge, InN, InP, GaAs, AlSe, CdSe, AlAs, GaP, ZnTe, CdTe, and InAs are preferable.
　より好ましくはコア／シェル構造半導体ナノ粒子のシェル部と同一の組成を持つシェルが適用される（コア／シェル構造半導体ナノ粒子がＩｎＰ／ＺｎＳ、ＣｄＴｅ／ＺｎＳ、及びＣｄＳｅ／ＺｎＳであればＺｎＳが、Ｓｉ／ＳｉＯ2であればＳｉＯ2）。 More preferably, a shell having the same composition as the shell part of the core / shell structure semiconductor nanoparticles is applied (if the core / shell structure semiconductor nanoparticles are InP / ZnS, CdTe / ZnS, and CdSe / ZnS, ZnS In the case of Si / SiO 2 , SiO 2 ).
　再シェリング時のシェル厚は、再シェリング時に添加する量を変化させることで容易にコントロール可能である。再シェリング時のシェル厚は、半導体ナノ粒子集積体の平均粒径から半導体ナノ粒子凝集隊の平均粒径を引いた値であり、その厚さは２～２００ｎｍの厚さが好ましく、さらに、５～２０ｎｍの範囲内の厚さとすることが好ましい。 The shell thickness at the time of re-shelling can be easily controlled by changing the amount added at the time of re-shelling. The shell thickness at the time of re-shelling is a value obtained by subtracting the average particle size of the semiconductor nanoparticle aggregate from the average particle size of the semiconductor nanoparticle aggregate, and the thickness is preferably 2 to 200 nm. The thickness is preferably in the range of ˜20 nm.
　（半導体ナノ粒子の製造方法）
　本発明に係る半導体ナノ粒子の製造方法としては、液相法又は気相法による方法を採用できる。 (Method for producing semiconductor nanoparticles)
As a method for producing semiconductor nanoparticles according to the present invention, a liquid phase method or a gas phase method can be employed.
　液相法の製造方法としては、沈殿法、共沈法、ゾル－ゲル法、均一沈殿法、還元法などがある。そのほかに、逆ミセル法、超臨界水熱合成法、などもナノ粒子を作製する上で優れた方法である（例えば、特開２００２－３２２４６８号、特開２００５－２３９７７５号、特開平１０－３１０７７０号、特開２０００－１０４０５８号公報等を参照。）。 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 nanoparticles (for example, JP 2002-322468, JP 2005-239775, JP 10-310770 A). No., JP 2000-104058 A, etc.).
　なお、液相法により、半導体ナノ粒子の集合体を製造する場合においては、当該半導体の前駆体を還元反応により還元する工程を有する製造方法であることも好ましい。 In addition, when manufacturing the aggregate | assembly of a semiconductor nanoparticle 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.
　また、当該半導体前駆体の反応を界面活性剤の存在下で行う工程を有する態様が好ましい。なお、本発明に係る半導体前駆体は、上記の半導体材料として用いられる元素を含む化合物であり、たとえば半導体がＳｉの場合、半導体前駆体としてはＳｉＣｌ4などが挙げられる。その他半導体前駆体としては、ＩｎＣｌ3、Ｐ（ＳｉＭｅ3）3、ＺｎＭｅ2、ＣｄＭｅ2、ＧｅＣｌ4、トリブチルホスフィンセレンなどが挙げられる。 Moreover, the aspect which has the process of performing reaction of the said semiconductor precursor in presence of surfactant 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, the semiconductor precursor includes SiCl 4 . Other semiconductor precursors include InCl 3 , P (SiMe 3 ) 3 , ZnMe 2 , CdMe 2 , GeCl 4 , tributylphosphine selenium and the like.
　反応前駆体の反応温度としては、半導体前駆体の沸点以上かつ溶媒の沸点以下であれば、特に制限はないが、７０～１１０℃の範囲が好ましい。 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.
　〈還元剤〉
　半導体前駆体を還元する還元剤としては、従来周知の種々の還元剤を反応条件に応じて選択し用いることができる。本発明においては、還元力の強さの観点から、水素化アルミニウムリチウム（ＬｉＡｌＨ4）、水素化ホウ素ナトリウム（ＮａＢＨ4）、水素化ビス（２－メトキシエトキシ）アルミニウムナトリウム、水素化トリ（ｓｅｃ－ブチル）ホウ素リチウム（ＬｉＢＨ（ｓｅｃ－Ｃ4Ｈ9）3）及び水素化トリ（ｓｅｃ－ブチル）ホウ素カリウム、水素化トリエチルホウ素リチウムなどの還元剤が好ましい。特に、還元力の強さから水素化アルミニウムリチウム（ＬｉＡｌＨ4）が好ましい。 <Reducing agent>
As the reducing agent for reducing the semiconductor precursor, 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, trihydride (sec- Preferred are reducing agents such as lithium (butyl) boron (LiBH (sec-C 4 H 9 ) 3 ), potassium tri (sec-butyl) borohydride, lithium triethylborohydride. In particular, lithium aluminum hydride (LiAlH 4 ) is preferable because of its reducing power.
　〈溶媒〉
　半導体前駆体の分散用溶媒としては、従来周知の種々の溶媒を使用できるが、エチルアルコール、ｓｅｃ－ブチルアルコール、ｔ－ブチルアルコール等のアルコール類、トルエン、デカン、ヘキサンなどの炭化水素類溶媒を使用することが好ましい。本発明においては、特に、トルエン等の疎水性の溶媒が分散用溶媒として好ましい。 <solvent>
Various known solvents can be used as the solvent for dispersing the semiconductor precursor. Alcohols such as ethyl alcohol, sec-butyl alcohol and t-butyl alcohol, and 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.
　〈界面活性剤〉
　界面活性剤としては、従来周知の種々の界面活性剤を使用でき、陰イオン、非イオン、陽イオン、両性界面活性剤が含まれる。なかでも第四級アンモニウム塩系である、テトラブチルアンモニウムクロリド、ブロミド又はヘキサフルオロホスフェート、テトラオクチルアンモニウムブロミド（ＴＯＡＢ）、又はトリブチルヘキサデシルホスホニウムブロミドが好ましい。特に、テトラオクチルアンモニウムブロミドが好ましい。 <Surfactant>
As the 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.
　なお、液相法による反応は、液中の溶媒を含む化合物の状態により大きく変化する。単分散性の優れたナノサイズの粒子を製造する際には、特に注意を要する必要がある。例えば、逆ミセル反応法では、界面活性剤の濃度や種類により、反応場となる逆ミセルの大きさや状態が変わってくるため、ナノ粒子が形成される条件が限られてしまう。したがって、適切な界面活性剤と溶媒との組み合わせが必要となる。 The reaction by the liquid phase method varies greatly depending on the state of the compound containing the solvent in the liquid. 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.
　気相法の製造方法としては、（１）対向する原料半導体を電極間で発生させた第一の高温プラズマによって蒸発させ、減圧雰囲気中において無電極放電で発生させた第二の高温プラズマ中に通過させる方法（例えば特開平６－２７９０１５号公報参照。）、（２）電気化学的エッチングによって、原料半導体からなる陽極からナノ粒子を分離・除去する方法（例えば特表２００３－５１５４５９号公報参照。）、（３）レーザーアブレーション法（例えば特開２００４－３５６１６３号参照。）、（４）高速スパッタリング法（例えば特開２００４－２９６７８１号参照。）などが用いられる。また、原料ガスを低圧状態で気相反応させて、粒子を含む粉末を合成する方法も、好ましく用いられる。 As a manufacturing method of the vapor phase method, (1) the opposing raw material semiconductor is evaporated by the first high temperature plasma generated between the electrodes, and in the second high temperature plasma generated by electrodeless discharge in a reduced pressure atmosphere. (2) A method of separating and removing nanoparticles from an anode made of a raw material semiconductor by electrochemical etching (for example, see Japanese Patent Application Laid-Open No. 2003-515459). ), (3) laser ablation (for example, see JP-A-2004-356163), (4) high-speed sputtering method (for example, see JP-A-2004-296781), etc. A method of synthesizing a powder containing particles by reacting a raw material gas in a gas phase in a low pressure state is also preferably used.
　なお、半導体ナノ粒子の凝集体及び半導体ナノ粒子集積体の製造方法の概要については、上述したが、具体的方法は、実施例の説明において詳述する。 In addition, although the outline | summary of the manufacturing method of the aggregate of a semiconductor nanoparticle and a semiconductor nanoparticle aggregate | assembly was mentioned above, the specific method is explained in full detail in description of an Example.
　（応用例）
　以下において、代表的な応用例について説明する。 (Application examples)
In the following, typical application examples will be described.
　（生体物質標識剤とバイオイメージング）
　本発明の半導体ナノ粒子集積体は、生体物質蛍光標識剤に適応することができる。また、標的（追跡）物質を有する生細胞もしくは生体に本発明に係る生体物質標識剤を添加することで、標的物質と結合もしくは吸着し、当該結合体もしくは吸着体に所定の波長の励起光を照射し、当該励起光に応じて蛍光半導体微粒子から発生する所定の波長の蛍光を検出することにより、上記標的（追跡）物質の蛍光動態イメージングを行うことができる。 (Biological substance labeling agents and bioimaging)
The semiconductor nanoparticle 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 generated from the fluorescent semiconductor fine particles according to the excitation light, fluorescence dynamic imaging of the target (tracking) substance can be performed.
　すなわち、本発明に係る生体物質標識剤は、バイオイメージング法（生体物質を構成する生体分子やその動的現象を可視化する技術手段）に利用することができる。 That is, the biological material labeling agent according to the present invention can be used for a bioimaging method (technical means for visualizing biological molecules constituting the biological material and dynamic phenomena thereof).
　〔半導体ナノ粒子集積体の親水化処理〕
　上述した半導体ナノ粒子集積体表面は、一般的には、疎水性であるため、例えば生体物質標識剤として使用する場合は、このままでは水分散性が悪く、半導体ナノ粒子集積体が凝集してしまう等の問題があるため、半導体ナノ粒子集積体の表面を親水化処理することが好ましい。 [Hydrophilic treatment of semiconductor nanoparticle assembly]
Since the surface of the semiconductor nanoparticle aggregate described above is generally hydrophobic, for example, when used as a biological material labeling agent, the water dispersibility is poor as it is, and the semiconductor nanoparticle aggregate is aggregated. Therefore, it is preferable to hydrophilize the surface of the semiconductor nanoparticle assembly.
　親水化処理の方法としては例えば、表面の親油性基をピリジン等で除去した後に半導体ナノ粒子集積体表面に表面修飾剤を化学的及び／又は物理的に結合させる方法がある。表面修飾剤としては、親水基として、カルボキシル基・アミノ基を持つものが好ましく用いられ、具体的にはメルカプトプロピオン酸、メルカプトウンデカン酸、アミノプロパンチオールなどがあげられる。具体的には、例えば、Ｇｅ／ＧｅＯ2型ナノ粒子１０-5ｇをメルカプトウンデカン酸０．２ｇが溶解した純水１０ｍｌ中に分散させて、４０℃、１０分間攪拌し、シェルの表面を処理することで無機ナノ粒子のシェルの表面をカルボキシル基で修飾することができる。 As a hydrophilic treatment method, for example, there is a method in which a surface modifying agent is chemically and / or physically bonded to the surface of the semiconductor nanoparticle assembly after removing the lipophilic group on the surface with pyridine or the like. As the surface modifier, those having a carboxyl group / amino group as a hydrophilic group are preferably used, and specific examples include mercaptopropionic acid, mercaptoundecanoic acid, aminopropanethiol and the like. Specifically, for example, 10 −5 g of Ge / GeO 2 type nanoparticles are dispersed in 10 ml of pure water in which 0.2 g of mercaptoundecanoic acid is dissolved, and stirred at 40 ° C. for 10 minutes to treat the surface of the shell. By doing so, the surface of the shell of the inorganic nanoparticles can be modified with a carboxyl group.
　〔生体物質標識剤〕
　本発明に係る生体物質標識剤は、上述した親水化処理された半導体ナノ粒子集積体と、分子標識物質と有機分子を介して結合させて得られる。 [Biological substance labeling agent]
The biological material labeling agent according to the present invention is obtained by binding the above-described hydrophilic nanoparticle aggregate, the molecular labeling material, and an organic molecule.
　〈分子標識物質〉
　本発明に係る生体物質標識剤は分子標識物質が目的とする生体物質と特異的に結合及び／又は反応することにより、生体物質の標識が可能となる。 <Molecular labeling substance>
The biological substance labeling agent according to the present invention can label a biological substance by specifically binding and / or reacting with the target biological substance.
　当該分子標識物質としては、例えば、ヌクレオチド鎖、抗体、抗原及びシクロデキストリン等が挙げられる。 Examples of the molecular labeling substance include nucleotide chains, antibodies, antigens, and cyclodextrins.
　〈有機分子〉
　本発明に係る生体物質標識剤は、親水化処理された半導体ナノ粒子集積体と、分子標識物質とが有機分子により結合されている。当該有機分子としては半導体ナノ粒子集積体と分子標識物質とを結合できる有機分子であれば特に制限はないが、例えば、タンパク質中でも、アルブミン、ミオグロビン及びカゼイン等、またタンパク質の一種であるアビジンをビオチンと共に用いることも好適に用いられる。上記結合の態様としては特に限定されず、共有結合、イオン結合、水素結合、配位結合、物理吸着及び化学吸着等が挙げられる。結合の安定性から共有結合などの結合力の強い結合が好ましい。 <Organic molecule>
In the biological material labeling agent according to the present invention, a hydrophilic semiconductor nanoparticle aggregate and a molecular labeling substance are bound by an organic molecule. The organic molecule is not particularly limited as long as it is an organic molecule that can bind the semiconductor nanoparticle aggregate and the molecular labeling substance. For example, among proteins, albumin, myoglobin, casein, etc. It is also preferably used together. The form of the bond is not particularly limited, and examples thereof include covalent bond, ionic bond, hydrogen bond, 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.
　具体的には、半導体ナノ粒子集積体をメルカプトウンデカン酸で親水化処理した場合は、有機分子としてアビジン及びビオチンを用いることができる。この場合親水化処理されたナノ粒子のカルボキシル基はアビジンと好適に共有結合し、アビジンがさらにビオチンと選択的に結合し、ビオチンがさらに生体物質標識剤と結合することにより生体物質標識剤となる。 Specifically, when the semiconductor nanoparticle aggregate is hydrophilized with mercaptoundecanoic acid, avidin and biotin can be used as organic molecules. In this case, the carboxyl group of the nanoparticles subjected to hydrophilic treatment is preferably covalently bonded to avidin, and avidin further selectively binds to biotin, and biotin further binds to the biological material labeling agent to become a biological material labeling agent. .
　以下、実施例により本発明をより詳細に説明するが、本発明はこれに限定されるものではない。 Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.
　（実施例１、２、３）；表１参照、以下同様。 (Examples 1, 2, and 3); see Table 1, and so on
　（ＩｎＰコア粒子及びＩｎＰ／ＺｎＳコア／シェル構造半導体ナノ粒子の合成）
　ＩｎＰコア粒子の合成は、下記の加熱溶液法によって行った。 (Synthesis of InP core particles and InP / ZnS core / shell structure semiconductor nanoparticles)
InP core particles were synthesized by the following heated solution method.
　三つ口フラスコに６ｍｌのオクタデセンを入れ、その溶媒中に１ｍｌのオクタデセンに溶解させたＩｎ（ａｃａｃ）3とトリス（トリメチルシリル）ホスフィンをＩｎとＰの比がＩｎ／Ｐ＝１／１となるように加え、アルゴン雰囲気中で３００℃、１ｈ反応させＩｎＰコア粒子（分散液）を得た。 6 ml of octadecene is placed in a three-necked flask, and In (acac) 3 and tris (trimethylsilyl) phosphine dissolved in 1 ml of octadecene are dissolved in the solvent so that the ratio of In to P becomes In / P = 1/1. In addition, an InP core particle (dispersion liquid) was obtained by reacting at 300 ° C. for 1 hour in an argon atmosphere.
　このようにして得られたＩｎＰコア粒子は６３０ｎｍに極大発光波長を持った粒子であった。 The InP core particles thus obtained were particles having a maximum emission wavelength at 630 nm.
　ＩｎＰ／ＺｎＳコア／シェル粒子の合成は、３００℃、１ｈ反応後のＩｎＰコア粒子分散液を８０℃まで放冷した後、その分散液に１ｍｌのオクタデセンに溶解させたステアリン酸亜鉛＋硫黄をＩｎ、Ｐ、Ｚｎ、Ｓの比がＩｎ／Ｐ／Ｚｎ／Ｓ＝１／１／１／１となるように加え、８０℃から２３０℃に昇温し、３０分反応させることにより得た。このようにして得られたＩｎＰ／ＺｎＳコア／シェル半導体ナノ粒子はＩｎＰコア粒子と同様に６３０ｎｍに極大発光波長を持った粒子であった。 InP / ZnS core / shell particles were synthesized by allowing the InP core particle dispersion after the 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 InP / ZnS core / shell semiconductor nanoparticles thus obtained were particles having a maximum emission wavelength at 630 nm, similar to the InP core particles.
　（半導体ナノ粒子凝集体形成）
　ＩｎＰ又はＩｎＰ／ＺｎＳの凝集体は上記反応後の分散液を放冷し、室温まで冷却した後に貧溶媒であるエタノールをＩｎＰコア粒子又はＩｎＰ／ＺｎＳコア／シェル半導体ナノ粒子の１０倍モル量加えることで得た。 (Semiconductor nanoparticle aggregate formation)
The aggregate of InP or InP / ZnS is allowed to cool the dispersion after the above reaction, and after cooling to room temperature, ethanol as a poor solvent is added in a 10-fold molar amount of InP core particles or InP / ZnS core / shell semiconductor nanoparticles I got it.
　（半導体ナノ粒子集積体形成）
　半導体ナノ粒子凝集体含有分散液を遠心分離し、数回エタノールで洗浄する。洗浄後の沈殿にオクタデセンを加え、溶媒をオクタデセンに再置換した。その際、凝集体の再分散は起こらず、凝集体の粒径を維持したままであった。 (Semiconductor nanoparticle assembly formation)
The semiconductor nanoparticle aggregate-containing dispersion is centrifuged and washed several times with ethanol. Octadecene was added to the washed precipitate, and the solvent was replaced with octadecene. At that time, re-dispersion of the aggregate did not occur and the particle size of the aggregate was maintained.
　このオクタデセン置換の凝集体分散液を三つ口フラスコに移し、８０℃に加熱し、ステアリン酸亜鉛＋硫黄を加え（量はＺｎ／Ｓ＝１でＩｎＰ又はＩｎＰ／ＺｎＳコア粒子の１０倍モル量のＺｎＳとなるように加えた）、８０℃から２３０℃に昇温し、３０分間反応させることで再シェリングし、半導体ナノ粒子集積体を得た。凝集体を集積体にする際の再シェリングはＩｎＰ又はＩｎＰ／ＺｎＳコア粒子の１０倍モル量のＺｎＳを加えた。 This octadecene-substituted aggregate dispersion is transferred to a three-necked flask, heated to 80 ° C., and zinc stearate + sulfur is added (the amount is Zn / S = 1 and the amount is 10 times the amount of InP or InP / ZnS core particles). The temperature was raised from 80 ° C. to 230 ° C. and reacted for 30 minutes to re-shell, thereby obtaining a semiconductor nanoparticle aggregate. In re-shelling when the aggregates were aggregated, ZnS was added in an amount 10 times the amount of InP or InP / ZnS core particles.
　（実施例５，６，７）
　（Ｓｉコア粒子及びＳｉ／ＳｉＯ2コア／シェル半導体ナノ粒子合成）
　Ｓｉ／ＳｉＯ2コア／シェル半導体ナノ粒子は、アモルファスＳｉ（Ｓｉｇｍａ－Ａｌｄｒｉｃｈ社製）をＨＮＯ3／ＨＦ溶液で処理することにより得た。 (Examples 5, 6, and 7)
(Synthesis of Si core particles and Si / SiO 2 core / shell semiconductor nanoparticles)
Si / SiO 2 core / shell semiconductor nanoparticles were obtained by treating amorphous Si (manufactured by Sigma-Aldrich) with an HNO 3 / HF solution.
　アモルファスＳｉ　２ｇを２％ＨＮＯ3／２％ＨＦ＝１／１の水溶液２０ｍｌ中に入れ、２０分間反応させることにより６００ｎｍに極大発光波長を持つＳｉ／ＳｉＯ2コア／シェル半導体ナノ粒子を得た。 2 g of amorphous Si was placed in 20 ml of an aqueous solution of 2% HNO 3 /2% HF = 1/1 and reacted for 20 minutes to obtain Si / SiO 2 core / shell semiconductor nanoparticles having a maximum emission wavelength at 600 nm.
　このＳｉ／ＳｉＯ2コア／シェル半導体ナノ粒子に５０％のＨＦを０．５ｍｌ加えて、表面のＳｉＯ2を溶解しＳｉコア粒子とした。このようにして得られたＳｉコア粒子は６３０ｎｍに極大発光波長を持った粒子であった。 To this Si / SiO 2 core / shell semiconductor nanoparticles, 0.5 ml of 50% HF was added to dissolve the surface SiO 2 to obtain Si core particles. The Si core particles thus obtained were particles having a maximum emission wavelength at 630 nm.
　（半導体ナノ粒子凝集体形成）
　Ｓｉ又はＳｉ／ＳｉＯ2凝集体は、上記Ｓｉ／ＳｉＯ2コア／シェルもしくはＳｉコア半導体ナノ粒子分散液にＣａＣＯ3を加えＨＦをＣａＦとして晶析させた後、濾過を行いＣａＦを除去した後、貧溶媒であるアセトンを加えることにより得ている。 (Semiconductor nanoparticle aggregate formation)
After Si or Si / SiO 2 aggregate is crystallized as HF as CaF by adding CaCO 3 to the Si / SiO 2 core / shell or Si core semiconductor nanoparticle dispersion, the CaF is removed by filtration. It is obtained by adding acetone, which is a poor solvent.
　（半導体ナノ粒子集積体形成）
　集積化に関しては上記Ｓｉ／ＳｉＯ2コア／シェル又はＳｉコア半導体ナノ粒子凝集体溶液に１００倍モル量のテトラエトキシシラン（ＴＥＯＳ）を加え、ＨＣｌを添加し、２５℃、ｐＨ＝６に調整し、強撹拌し加水分解反応を起こすことにより得た。 (Semiconductor nanoparticle assembly formation)
For integration, 100 times molar amount of tetraethoxysilane (TEOS) is added to the Si / SiO 2 core / shell or Si core semiconductor nanoparticle aggregate solution, HCl is added, and the pH is adjusted to 25 ° C. and pH = 6. It was obtained by stirring vigorously and causing a hydrolysis reaction.
　（実施例８、９、１０）
　（ＣｄＳｅコア粒子及びＣｄＳｅ／ＺｎＳコア／シェル半導体ナノ粒子の合成）
　ＣｄＳｅコア粒子、及びＣｄＳｅ／ＺｎＳコア／シェル半導体ナノ粒子の合成は以下のように行った。 (Examples 8, 9, and 10)
(Synthesis of CdSe core particles and CdSe / ZnS core / shell semiconductor nanoparticles)
Synthesis of CdSe core particles and CdSe / ZnS core / shell semiconductor nanoparticles was performed as follows.
　Ａｒ気流下、トリ－ｎ－オクチルホスフィンオキシド（ＴＯＰＯ）７．５ｇに、ステアリン酸２．９ｇ、ｎ－テトラデシルホスホン酸６２０ｍｇ、及び、酸化カドミニウム２５０ｍｇを加え、３７０℃に加熱混合した。これを２７０℃まで放冷させた後、トリブチルフォスフィン２．５ｍｌにセレン２００ｍｇを溶解させた溶液を加え、減圧乾燥し、ＴＯＰＯで被覆されたＣｄＳｅコア半導体ナノ粒子を得た。 In 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 to 370 ° C. After allowing 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コア／シェル半導体ナノ粒子合成は得られたＣｄＳｅコア粒子に、ＴＯＰＯ１５ｇを加えて加熱し、引き続き２７０℃でトリオクチルホスフィン１０ｍｌにジエチルジチオカルバミン酸亜鉛１．１ｇを溶解した溶液を加え、ＣｄＳｅ／ＺｎＳコア／シェル半導体ナノ粒子を得た。 CdSe / ZnS core / shell semiconductor nanoparticle synthesis was performed 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.
　（半導体ナノ粒子凝集体形成）
　ＣｄＳｅ又はＣｄＳｅ／ＺｎＳの凝集体は上記反応後の溶液を放冷し、室温まで冷却した後に貧溶媒であるエタノールをＣｄＳｅコア又はＣｄＳｅ／ＺｎＳコア／シェル半導体ナノ粒子の１０倍モル量加えることで得た。 (Semiconductor nanoparticle aggregate formation)
The aggregate of CdSe or CdSe / ZnS is allowed to cool the solution after the above reaction, and after cooling to room temperature, ethanol as a poor solvent is added in a 10-fold molar amount of CdSe core or CdSe / ZnS core / shell semiconductor nanoparticles. Obtained.
　（半導体ナノ粒子集積体形成）
　半導体ナノ粒子凝集体含有分散液を遠心分離し、数回エタノールで洗浄する。洗浄後の沈殿にオクタデセンを加え、溶媒をオクタデセンに置換した。その際、凝集体の再分散は起こらず、凝集体の粒径を維持したままであった。 (Semiconductor nanoparticle assembly formation)
The semiconductor nanoparticle aggregate-containing dispersion is centrifuged and washed several times with ethanol. Octadecene was added to the washed precipitate, and the solvent was replaced with octadecene. At that time, re-dispersion of the aggregate did not occur and the particle size of the aggregate was maintained.
　このオクタデセン置換の凝集体溶液を三つ口フラスコに移し、８０℃に加熱し、ステアリン酸亜鉛＋硫黄を加え、８０℃から２３０℃に昇温し、３０分反応させることで再シェリングし、半導体ナノ粒子集積体を得た。凝集体を集積体にする際の再シェリングはＣｄＳｅ又はＣｄＳｅ／ＺｎＳコア粒子の１０倍モル量のＺｎＳを加えた。 This octadecene-substituted aggregate solution is transferred to a three-necked flask, heated to 80 ° C., zinc stearate + sulfur is added, the temperature is raised from 80 ° C. to 230 ° C., and reacted for 30 minutes to re-shell. A nanoparticle assembly was obtained. The re-shelling when the aggregates were aggregated added ZnS in a 10-fold molar amount of CdSe or CdSe / ZnS core particles.
　（実施例１２、１３、１４）
　（ＣｄＴｅコア粒子及びＣｄＴｅ／ＺｎＳコア／シェル半導体ナノ粒子の合成）
　ＣｄＴｅコア粒子、ＣｄＴｅ／ＺｎＳコア／シェル半導体ナノ粒子に関しては特開２００５－２８１０１９号公報の実施例１に従い合成した。 (Examples 12, 13, and 14)
(Synthesis of CdTe core particles and CdTe / ZnS core / shell semiconductor nanoparticles)
CdTe core particles and CdTe / ZnS core / shell semiconductor nanoparticles were synthesized according to Example 1 of JP-A-2005-281019.
　ＣｄＴｅコア粒子については、ヒェミー、１００巻、１７７２頁（１９９６）による方法に従って合成した。 The CdTe core particles were synthesized according to the method according to Hemy, Volume 100, page 1772 (1996).
　すなわち、アルゴンガス雰囲気下、界面活性剤としてのチオグリコール酸（ＨＯＯＣＣＨ2ＳＨ）の存在下で２５℃、ｐＨ＝１１．４に調整した過塩素酸カドミウム水溶液を激しく撹拌しながら、テルル化水素ガスを反応させた。この水溶液を大気雰囲気下で６日間還流することにより、ＣｄＴｅコア粒子を得た。 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.
　このようにして得られたＣｄＴｅコア粒子は６４０ｎｍに極大発光波長を持った粒子であった。 The CdTe core particles thus obtained were particles having a maximum emission wavelength at 640 nm.
　ＣｄＴｅ／ＺｎＳコア／シェル粒子の合成は、この水溶液を８０℃まで加熱した後、その溶液に１ｍｌの水に溶解させたステアリン酸亜鉛＋硫黄をＣｄ、Ｔｅ、Ｚｎ、Ｓの比がＣｄ／Ｔｅ／Ｚｎ／Ｓ＝１／１／１／１となるように加え、８０℃から２３０℃に昇温し、３０分反応させることにより得た。 CdTe / ZnS core / shell particles were synthesized by heating the aqueous solution to 80 ° C., and then adding zinc stearate + sulfur dissolved in 1 ml of water to the Cd / Te / Zn / S ratio. It was obtained by adding / Zn / S = 1/1/1/1, raising the temperature from 80 ° C. to 230 ° C., and reacting for 30 minutes.
　（半導体ナノ粒子凝集体形成）
　ＣｄＴｅもしくはＣｄＴｅ／ＺｎＳの凝集体は上記反応後の溶液を放冷し、室温まで冷却した後に貧溶媒であるエタノールをＣｄＴｅコア粒子又はＣｄＴｅ／ＺｎＳコア／シェル半導体ナノ粒子の１０倍モル量加えることで得た。 (Semiconductor nanoparticle aggregate formation)
Aggregates of CdTe or CdTe / ZnS are allowed to cool the solution after the above reaction, and after cooling to room temperature, ethanol as a poor solvent is added in a 10-fold molar amount of CdTe core particles or CdTe / ZnS core / shell semiconductor nanoparticles. I got it.
　（半導体ナノ粒子集積体形成）
　半導体ナノ粒子凝集体含有分散液を遠心分離し、数回エタノールで洗浄する。洗浄後の沈殿にオクタデセンを加え、溶媒をオクタデセンに置換した。その際、凝集体の再分散は起こらず、凝集体の粒径を維持したままであった。 (Semiconductor nanoparticle assembly formation)
The semiconductor nanoparticle aggregate-containing dispersion is centrifuged and washed several times with ethanol. Octadecene was added to the washed precipitate, and the solvent was replaced with octadecene. At that time, re-dispersion of the aggregate did not occur and the particle size of the aggregate was maintained.
　このオクタデセン置換の凝集体溶液を三つ口フラスコに移し、８０℃に加熱し、ステアリン酸亜鉛＋硫黄（量はＺｎ／Ｓ＝１でＣｄＴｅ又はＣｄＴｅ／ＺｎＳコア粒子の１０倍モル量のＺｎＳとなるように加えた）を加え、８０℃から２３０℃に昇温し、３０分反応させることで再シェリングし、半導体ナノ粒子集積体を得た。 This octadecene-substituted aggregate solution was transferred to a three-necked flask and heated to 80 ° C., and zinc stearate + sulfur (the amount was Zn / S = 1 and 10 times the molar amount of ZnS as CdTe or CdTe / ZnS core particles). Was added, and the temperature was raised from 80 ° C. to 230 ° C. and reacted for 30 minutes for re-shelling to obtain a semiconductor nanoparticle aggregate.
　凝集体を集積体にする際の再シェリングはＣｄＴｅ又はＣｄＴｅ／ＺｎＳコア粒子の１０倍モル量のＺｎＳを加えている。 For re-shelling when the aggregates are aggregated, ZnS is added in an amount 10 times the amount of CdTe or CdTe / ZnS core particles.
　（実施例４、１１、１５）
　特開２００５－２８１０１９号公報記載の実施例１に従い、シリカマトリックス中にそれぞれＩｎＰ／ＺｎＳ、ＣｄＳｅ／ＺｎＳ、ＣｄＴｅ／ＺｎＳが存在する半導体ナノ粒子集積体を作製した。 (Examples 4, 11, and 15)
According to Example 1 described in Japanese Patent Application Laid-Open No. 2005-281019, a semiconductor nanoparticle aggregate in which InP / ZnS, CdSe / ZnS, and CdTe / ZnS exist in the silica matrix was produced.
　ＩｎＰ／ＺｎＳ、ＣｄＳｅ／ＺｎＳコア／シェル、及びＣｄＴｅ／ＺｎＳ半導体ナノ粒子分散液を２５℃、ｐＨ＝１０の条件下、界面活性剤としてチオグリコール酸を加えることにより水溶化した。その後、疎水性有機溶媒としてのイソオクタン（２，２，４－トリメチルペンタン）２５ｍｌに、逆ミセル（逆マイクロエマルジョン）を形成させるために必要な界面活性剤ビス（２－エチルヘキシル）スルホこはく酸ナトリウム（エーロゾルＯＴ）（「ＡＯＴ」とも表記する。）１．１１１５ｇを溶解し、次に、この溶液を撹拌しながら、水０．７４ｍｌと、上記の水溶化ＩｎＰ／ＺｎＳ、ＣｄＳｅ／ＺｎＳ、ＣｄＴｅ／ＺｎＳコア／シェル半導体ナノ粒子溶液０．３ｍｌ加えて溶解した。次に、この溶液を撹拌しながら、ゾル－ゲルガラスの前駆体として、アルコキシドであるテトラエトキシシラン（ＴＥＯＳ）０．３９９ｍｌ、及び、有機アルコキシシランである３－アミノプロピルトリメトキシシラン（ＡＰＳ）０．０７９ｍｌを加えた。 The InP / ZnS, CdSe / ZnS core / shell, and CdTe / ZnS semiconductor nanoparticle dispersion were water-solubilized by adding thioglycolic acid as a surfactant under the conditions of 25 ° C. and pH = 10. Thereafter, the surfactant bis (2-ethylhexyl) sulfosuccinate sodium (required for forming reverse micelle (reverse microemulsion) in 25 ml of isooctane (2,2,4-trimethylpentane) as a hydrophobic organic solvent ( (Aerosol OT) (also referred to as “AOT”) 1.1115 g was dissolved and then 0.74 ml of water and the above water-soluble InP / ZnS, CdSe / ZnS, CdTe / ZnS were mixed while stirring the solution. 0.3 ml of the core / shell semiconductor nanoparticle solution was added and dissolved. Next, while stirring this solution, 0.399 ml of tetraethoxysilane (TEOS) as an alkoxide and 0.3 aminopropyltrimethoxysilane (APS) as an organoalkoxysilane as a sol-gel glass precursor. 079 ml was added.
　この分散液を２日間撹拌することによりシリカマトリックス中にそれぞれＩｎＰ／ＺｎＳ、ＣｄＳｅ／ＺｎＳ、ＣｄＴｅ／ＺｎＳが存在する半導体ナノ粒子集積体とした。 The dispersion was stirred for 2 days to obtain a semiconductor nanoparticle aggregate in which InP / ZnS, CdSe / ZnS, and CdTe / ZnS were present in the silica matrix, respectively.
　以上で得た各種半導体ナノ粒子集積体についての内容と輝度測定の結果をまとめて表１に示す。 Table 1 summarizes the contents of the various semiconductor nanoparticle assemblies obtained above and the results of luminance measurement.
　なお、輝度測定は、光源として１４６ｎｍの真空紫外線ランプ（ウシオ社製）を使用し、真空チャンバー内にサンプルをセットし、真空度１．３３×１０Ｐａにて一定距離から照射し励起発光を輝度計で測定した。輝度の値については、実施例１のＩｎＰ粒子集積体の輝度を１０００としたときの相対値で示した。 The luminance measurement uses a 146 nm vacuum ultraviolet lamp (USHIO Inc.) as a light source, sets a sample in a vacuum chamber, and irradiates excitation light from a certain distance at a vacuum degree of 1.33 × 10 Pa. Measured with The luminance value is shown as a relative value when the luminance of the InP particle assembly of Example 1 is 1000.
　半導体ナノ粒子及び半導体ナノ粒子集積体の粒径（体積平均粒径）は、動的光散乱法による粒径測定装置（Ｍａｌｖｅｒｎ　Ｉｎｓｔｒｕｍｅｎｔｓ社製、Ｚｅｔａｓｉｚｅｒ　Ｎａｎｏ　Ｓ）を用いて、半導体ナノ粒子又は集積体作製直後（凝集前）の粒径分布を測定することにより求めた。なお、平均粒径（体積平均粒径）は、粒径分布のピーク（中心）位置の粒径とした。 The particle size (volume average particle size) of the semiconductor nanoparticles and the semiconductor nanoparticle aggregate is determined by using a particle size measuring device (Malvern Instruments, Zetasizer Nano S) by dynamic light scattering method. It was determined by measuring the particle size distribution immediately after production (before aggregation). The average particle size (volume average particle size) was the particle size at the peak (center) position of the particle size distribution.
　また、半導体ナノ粒子の内包数の計算は以下のようにして行った。 Moreover, the calculation of the number of semiconductor nanoparticles included was performed as follows.
　まず、半導体ナノ粒子の元素比を、シーケンシャル形高周波プラズマ発光分析装置（ＩＣＰＳ－７５００　島津製作所製）を用いて計測した。その後、再シェリングされた半導体ナノ粒子集積体の元素比を上記高周波プラズマ発光分析装置（ＩＣＰ－ＡＥＳ）で計測することにより、再シェリングに用いられた濃度を計算した。半導体ナノ粒子、再シェリング化合物の密度は既知であるので、上記動的光散乱法で計算した平均粒径と合わせて内包数を見積もった。 First, the elemental ratio of the semiconductor nanoparticles was measured using a sequential type high frequency plasma emission analyzer (ICPS-7500, manufactured by Shimadzu Corporation). Thereafter, the element ratio of the re-shelled semiconductor nanoparticle assembly was measured with the high-frequency plasma emission analyzer (ICP-AES) to calculate the concentration used for re-shelling. Since the densities of the semiconductor nanoparticles and the re-shelling compound are known, the inclusion number was estimated together with the average particle diameter calculated by the dynamic light scattering method.
　以上の測定結果等を表１にまとめて示す。 The above measurement results are summarized in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に示した結果から明らかなように、本発明の半導体ナノ粒子の凝集体を再シェリングすることにより形成された半導体ナノ粒子集積体の発光輝度は、比較例に比べ、優れていることが分かる。 As apparent from the results shown in Table 1, the emission luminance of the semiconductor nanoparticle aggregate formed by re-shelling the aggregate of semiconductor nanoparticles of the present invention is superior to that of the comparative example. I understand.

Claims (5)

  1. 　コア／シェル構造を持つ半導体ナノ粒子を含有する半導体ナノ粒子集積体であって、半導体ナノ粒子の凝集体を再シェリングすることにより形成されたことを特徴とする半導体ナノ粒子集積体。 A semiconductor nanoparticle aggregate comprising semiconductor nanoparticles having a core / shell structure, wherein the semiconductor nanoparticle aggregate is formed by re-shelling an aggregate of semiconductor nanoparticles.
  2. 　前記コア／シェル構造を持つ半導体ナノ粒子のシェル部を構成する素材と再シェリング用の素材が、同一の化合物であること又は当該同一の化合物を含有することを特徴とする請求項１に記載の半導体ナノ粒子集積体。 The material constituting the shell part of the semiconductor nanoparticle having the core / shell structure and the material for re-shelling are the same compound or contain the same compound. Semiconductor nanoparticle assembly.
  3. 　前記コア／シェル構造を持つ半導体ナノ粒子のシェル部を構成する素材が、硫化亜鉛（ＺｎＳ）又は二酸化珪素（ＳｉＯ2）であることを特徴とする請求項１又は請求項２に記載の半導体ナノ粒子集積体。 3. The semiconductor nanostructure according to claim 1, wherein a material constituting the shell portion of the semiconductor nanoparticle having the core / shell structure is zinc sulfide (ZnS) or silicon dioxide (SiO 2 ). Particle aggregate.
  4. 　前記コア／シェル構造を持つ半導体ナノ粒子のコア部を構成する素材が、リン化インジウム（ＩｎＰ）、ケイ素（Ｓｉ）、セレン化カドミウム（ＣｄＳｅ）、及びテルル化カドミウム（ＣｄＴｅ）からなる群から選ばれる単体又は化合物であることを特徴とする請求項１から請求項３までのいずれか一項に記載の半導体ナノ粒子集積体。 The material constituting the core part of the semiconductor nanoparticles having the core / shell structure is selected from the group consisting of indium phosphide (InP), silicon (Si), cadmium selenide (CdSe), and cadmium telluride (CdTe). The semiconductor nanoparticle assembly according to any one of claims 1 to 3, wherein the semiconductor nanoparticle assembly is a simple substance or a compound.
  5. 　平均粒径が、５０～５００ｎｍの範囲内であることを特徴とする請求項１から請求項４までのいずれか一項に記載の半導体ナノ粒子集積体。 The semiconductor nanoparticle aggregate according to any one of claims 1 to 4, wherein the average particle diameter is in the range of 50 to 500 nm.
PCT/JP2011/054296 2010-06-16 2011-02-25 Semiconductor nanoparticle aggregate WO2011158531A1 (en)

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WO2009014588A2 (en) * 2007-06-29 2009-01-29 Eastman Kodak Company Light-emitting nanocomposite particles
JP2009281760A (en) * 2008-05-20 2009-12-03 Konica Minolta Medical & Graphic Inc Nanoparticle-containing silica, labeling material of biosubstance using it, and labeling method of biosubstance

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