JP2003064278A - Core-shell type semiconductor nanoparticles - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide semiconductor nanoparticles having both reduced photocatalytic activity and dispersibility in an organic matrix, and a resin composition using the same. SOLUTION: Core-shell type semiconductor nanoparticles comprising surface-modified molecules bonded to the surface of a core-shell type particle having a number average particle diameter of 2 to 50 nm comprising a semiconductor nanocrystal core and a conductive shell.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to semiconductor nanoparticles having a core-shell structure composed of a core (inner core) of semiconductor nanocrystals and a shell (outer shell) of a conductor.

[0002]

2. Description of the Related Art A method for dispersing semiconductor nanocrystal particles in a polymer matrix has been reported for the purpose of utilizing useful properties such as high refractive index and absorption / emission of light. JP-A-8-1
No. 10401 discloses that a semiconductor nanocrystal such as zinc oxide is formed into a composition with a curable resin monomer (such as an epoxy-based or acrylic-based) or an organic solvent by using a mechanical pulverizing / mixing device such as a ball mill, and then a curing film-forming step. By performing the above, a technique for obtaining a transparent film having a haze (turbidity) of about 0.2 at a film thickness of about 50 μm is disclosed. However, although the haze value is practical for film applications, a composition having a very high optical transparency in bulk (for example, the number average dispersed particle diameter of semiconductor nanocrystals is 50 nm at most). A composition having a haze value of zero in the measurement error range cannot be obtained by a mechanical grinding and mixing method such as this method.

On the other hand, a method of dispersing inorganic fine particles such as semiconductor crystal particles having an average primary particle diameter of about 1 to 150 nm in a polymer matrix to form a high refractive index film is disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-47004. Is disclosed in. In this publication, for example, titanium oxide having an average primary particle diameter of 50 nm is mixed with a photo-curable epoxy resin monomer in a solution in the presence of an organic surface treatment agent such as alkoxyaluminum, and the mixture is coated and then exposed to light. Cured, refractive index 2.0
0, a cured epoxy resin composition film having a film thickness of 127 nm (titanium oxide content is about 40 to 50% by volume) is described. Then, this publication teaches that the surface of the inorganic fine particles may be modified with a known organic surface treatment agent such as a silane coupling agent, and a coating film having a haze of about 5% or less can be formed. There is. However, generation of coarse secondary particles due to aggregation of primary particles of the inorganic fine particles cannot be sufficiently suppressed, and particularly preferably manufactured 50 to 200 n
Even in an ultra-thin film of about m, there is a problem in that haze is present at about 1%. In other words, the composition in the best dispersed state obtained by this method is also practical for ultrathin film applications, but it does not have a very high optical transparency in the bulk state.

Another one of the conventional techniques for dispersing semiconductor nanocrystals in a resin matrix represented by the above two publications.
One of the problems is the photocatalytic ability of semiconductor crystals such as zinc oxide and titanium oxide (the ability of semiconductor crystals to absorb light to generate electron-hole pairs, which decomposes organic substances on the semiconductor surface redoxly). It is pointed out that no measures have been taken to reduce this.

As a technique for reducing the photocatalytic activity of such semiconductor crystal particles, coating with silica has been proposed. For example, Nobuaki Ishii et al .; Fragrance Journal
1, 2001-1, Vol. 74-80 (2001), silica coating of semiconductor nanocrystals such as titanium oxide and zinc oxide has been investigated in cosmetic applications. But,
The particle diameter of the silica-coated semiconductor particles obtained by this conventional technique is at least about 88 nm, and it is possible to obtain a particle diameter (for example, about 50 nm or less) that does not impair the transparency of a transparent resin matrix such as an acrylic resin. There wasn't. This is a mechanical pulverization and mixing principle in which semiconductor nanocrystals in which particles having a primary particle diameter of about 25 nm are secondarily aggregated are used as raw materials, and a silica alkoxide, which is a silica raw material, is coated using a wet disintegrator. This is because you are using. Moreover, since the silica coating technology requires a silica layer having a theoretical film thickness of about 2.8 nm to reduce the photocatalytic activity to the extent required for sunscreen cosmetics, a transparent resin requiring higher light resistance. In the use of the composition for optical parts, it is necessary to use core-shell type particles having a thicker silica layer. Therefore, in the case of silica-coated core-shell type particles having a particle size (about 50 nm or less) that does not impair the transparency of the transparent resin matrix, the upper limit of the volume fraction of semiconductor crystals in one particle is limited. However, there has been a problem that the characteristics of the semiconductor crystal in the transparent resin composition (such as ultraviolet absorption and high refractive index) are insufficient.

As a technique for coating semiconductor crystal particles with another substance, there is a technique for coating the surface of inorganic particles such as semiconductor crystals (for example, titanium oxide) with a metal.
It is disclosed in the publication. This technique is a chemical plating method or a pretreatment method thereof, in which a reducing agent or the like is added in a metal salt aqueous solution to reduce a metal cation to generate a zero-valent metal, and the primary particle diameter is 10 mμ to 10 μm. On the surface of the inorganic particles, palladium, gold, silver, platinum, nickel,
It coats a metal such as cobalt, iron, or copper. Such a reaction is described in G.W. Schmid Edition; "Clusters
and Colloids ", VCH (Weinhe
Im, 1994). A coating liquid in which similar metal-coated inorganic particles are dispersed in a dispersion medium (solvent) is disclosed in JP-A-7-304616.
Here, colorless inorganic oxide ultrafine particles (having an average particle size of 80 nm or less) are used as the inorganic particles, and metal silver coating is used to form composite particles having an average particle size of 100 nm or less. However, in the metal-coated inorganic particles obtained by these two techniques, an organic compound other than the organic reducing agent used for the preparation is not intentionally bound to the surface of the particles, and therefore the average particle size of about 50 nm or less is particularly preferable. When the ultrafine particles having a diameter are used, there is a problem that secondary aggregation easily occurs and the dispersibility in the resin matrix is extremely deteriorated.

A method for synthesizing semiconductor nanocrystal particles in which surface-modifying molecules, which are expected to have good dispersibility in organic polymers and organic solvents, are bound to the surface is described in, for example, J. E. B. Ka
tari et al .; Phys. Chem. , Volume 98, 41
09-4117 (1994). The semiconductor nanocrystal particles obtained by this method have a structure in which a surface modifying molecule such as trioctylphosphine (hereinafter abbreviated as TOPO) is bonded to the surface of a compound semiconductor crystal particle such as cadmium selenide (CdSe). It not only has excellent solubility in organic solvents such as toluene and methylene chloride, but also has the characteristic that the particle size distribution is controlled to be extremely narrow. However, the semiconductor nanocrystal particles obtained by this method are acrylic resin typified by polymethylmethacrylate (commonly called PMMA), styrene resin typified by polystyrene, or aromatic polycarbonate resin typified by bisphenol A polycarbonate. However, the dispersibility in the general-purpose amorphous resin is insufficient, resulting in a drawback that an opaque resin composition is provided. In addition, applicable semiconductor nanocrystal species are zinc selenide (Zn
Se), cadmium sulfide (CdS), the above CdSe, cadmium telluride (CdTe), and other II-VI group compound semiconductors.

As a technique for improving such a defect, J. Lee et al .; Adv. Mater. , 12 volumes, 110
On page 2 (2000), there is reported a light emitting material in which the semiconductor nanocrystal particles having TOPO as a ligand are dispersed in a polylauryl methacrylate (abbreviated as PLMA) resin. However, since a special acrylic resin matrix called PLMA having a side chain of 12 carbon atoms is required, there is a problem that heat resistance and mechanical strength are poor.

As a resin composition containing other semiconductor nanocrystals, for example, a material in which CdSe ultrafine particles are dispersed in a matrix of poly (4-vinylpyridine) in an amount of about 10% by volume is described in EP 928245 (1999). But S. W. Haggata et al .; Mater. Ch
em. , Vol. 7, p. 1969 (1997), containing 31% by weight and 25% by weight of CdSe and ZnSe ultrafine particles, respectively.
The material dispersed to the extent that S. W. Haggata et al .;
Mater. Chem. , 6, 1771 (199
In 6), materials in which CdS and zinc sulfide (ZnS) ultrafine particles are dispersed by about 25% by weight and about 18% by weight, respectively, are reported. However, each of them requires a special polymer matrix containing a pyridine ring, and thus has a problem of poor light resistance (for example, color fastness).

As can be seen from the above-mentioned prior art, when dispersing semiconductor nanocrystals in a polymer matrix, there is no essential high transparency as a bulk material, but transparency that can be used as a film or thin film is provided. Distributed technology,
There are known techniques for reducing the photocatalytic activity of semiconductor nanocrystals by silica coating that reduces the semiconductor content, and nanocrystal dispersion techniques applicable only to special polymer matrices.
None of them were excellent in both transparency and efficient reduction of photocatalytic activity.

[0011]

DISCLOSURE OF THE INVENTION The present invention has a high degree of transparency in a bulk state even though it contains a semiconductor nanocrystal and has a function typified by ultraviolet absorption and high refractive index derived from the semiconductor nanocrystal. It is intended to provide semiconductor nanoparticles and a resin composition using the same, which can provide a transparent resin composition having excellent light resistance because the photocatalytic activity of the semiconductor nanocrystals is diminished. And

[0012]

Means for Solving the Problems As a result of extensive studies made by the present inventors in order to achieve the above object, as a result of coating the surface of a semiconductor nanocrystal with a conductor represented by a transition metal such as gold or silver, a core shell The photocatalytic activity of the semiconductor nanocrystals is remarkably diminished by forming the shaped particles, and at the same time, an organic compound having copolymerizability with the resin monomer or compatibility with the resin matrix is bound to the core-shell type particles as a surface-modifying molecule. The present invention has been accomplished by finding that by using the core-shell type semiconductor nanoparticles, it is possible to produce a resin composition having excellent transparency when the core-shell type semiconductor nanoparticles are dispersed in a resin. That is, the gist of the present invention lies in the following three points. 1. A semiconductor nanoparticle in which a surface-modifying molecule is bonded to the surface of a core-shell type particle having a number average particle diameter of 2 to 50 nm composed of a semiconductor nanocrystal core and a conductor shell. 2. The semiconductor nanoparticles are 0.01 to 80 in terms of ash content.
A resin composition containing 100% by weight. 3. Made of the above resin composition and having a film thickness of 0.05 to 3000
A thin film shaped article having a thickness of μm.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. [Semiconductor Nanoparticles] The semiconductor nanoparticles of the present invention are core-shell type particles composed of a core (inner core) of semiconductor nanocrystals and a shell (outer shell) of a conductor such as a metal. It will be. Such semiconductor nanoparticles are well dispersed in the resin matrix due to the effect of the surface-modifying molecules to give the resin composition of the present invention described later.

The number average particle diameter of the core-shell type particles is 2-5.
It is 0 nm. If the number average particle diameter is too small, the volume fraction of the semiconductor becomes small, or the crystallinity of the semiconductor becomes extremely low. Expression may be insufficient. Therefore, the lower limit is preferably 3n
m, more preferably 4 nm. On the other hand, if the number average particle size is too large, the transparency of the resin composition of the present invention may be extremely reduced. Therefore, the upper limit is preferably 4
It is 0 nm, more preferably 30 nm.

In determining the number average particle diameter in the present invention, a numerical value measured from a transmission electron microscope (TEM) observation image of a given particle is used. That is, the diameter of a circle having the same area as the observed particle image is defined as the particle size of the particle image. The number average particle diameter is calculated, for example, by a known statistical processing method of image data using the thus determined particle diameter. The number of particle images used for the statistical processing (the number of statistically processed data) is as large as possible. Naturally, it is desirable in the present invention that the number of the particle images randomly selected from the viewpoint of reproducibility is at least 50 or more, preferably 80 or more, more preferably 1 or more.
00 or more.

The thickness of the conductor shell in the core-shell type particles is usually about 0.5 to 10 nm. If the lower limit of the thickness of the shell is too small, the effect of reducing the photocatalytic activity of the semiconductor nanocrystals may be extremely reduced. Therefore, the thickness is preferably 1 nm, more preferably 2 nm. On the other hand, when the upper limit of the thickness of the shell is too large, the volume fraction of the semiconductor becomes small, which may result in insufficient expression of physical properties such as absorption and emission characteristics and high refractive index characteristics of semiconductor crystals. It is preferably 8 nm, more preferably 5 nm.
The thickness of the shell can be determined by the above TEM observation,
If necessary, the quantitative ratio with the core semiconductor, which is calculated from the elemental analysis value of the given particles, can be taken into account to determine with high accuracy.

The main effect of the conductor shell in the semiconductor nanoparticles of the present invention is to reduce the photocatalytic activity of the semiconductor nanocrystal core. The mechanism is not clear, but when an electron-hole pair generated by absorption of light by the semiconductor nanocrystal reaches the surface of the semiconductor nanocrystal, the conductor shell efficiently recombines them. The deactivating mechanism is speculated. Although the absorption spectrum of the semiconductor nanoparticles of the present invention is not limited,
In applications where light in a specific wavelength range such as the ultraviolet region is absorbed, the absorption edge wavelength of the absorption spectrum is 300 to 600 n.
It is preferably within the range of m. The lower limit value of the absorption edge wavelength range is more preferably 330 n for the purpose of absorbing the ultraviolet region which deteriorates the organic matrix such as synthetic resin.
m, more preferably 370 nm, while the upper limit is more preferably 550 in view of transparency in the visible region.
nm, more preferably 500 nm, most preferably 45 nm
It is 0 nm.

The content of the surface-modifying molecule in the semiconductor nanoparticles of the present invention depends on the molecular weight of the molecule, but is usually 5 to 70% by weight. From the viewpoint of efficiently dispersing the core-shell type particles with the minimum weight of the surface-modifying molecule,
The upper limit of the content of the surface modification molecule is preferably 50% by weight, more preferably 40% by weight, while the lower limit thereof is preferably 10% by weight, more preferably 15% by weight in view of dispersibility of nanoparticles. %. The content of such surface-modifying molecules is determined by thermogravimetric analysis in which the given semiconductor nanoparticles are heated at 600 ° C. for 90 minutes or more in a nitrogen atmosphere.

[Semiconductor Nanocrystal] The composition of the semiconductor nanocrystal constituting the core of the semiconductor nanoparticle of the present invention is not limited as long as it is a semiconductor crystal. The fact that the semiconductor composition has crystallinity means that, for example, the presence of a lattice pattern derived from the semiconductor crystal lattice in the TEM observation image,
Alternatively, it is confirmed by giving a diffraction peak corresponding to a known semiconductor crystal diffraction peak in the X-ray scattering spectrum.

Constituting the semiconductor nanocrystal in the present invention
The semiconductor composition is represented by C, S when the following specific examples are represented by composition formulas.
i, Ge, Sn, etc. Periodic Table Group 14 element simple substance, P (black
(Phosphorus) etc. Periodic Table Group 15 element simple substance, such as Se and Te
Periodic table Group 16 element simple substance, multiple periodic table such as SiC
Compound consisting of Group 14 element, SnO₂, Sn (II) Sn (I
V) S₃, SnS₂, SnS, SnSe, SnTe, Pb
Periodic table group 14 elements such as S, PbSe, PbTe and the period
Table Compounds with Group 16 elements, BN, BP, BAs, Al
N, AlP, AlAs, AlSb, GaN, GaP, G
aAs, GaSb, InN, InP, InAs, InS
Conversion of elements of Group 13 of the periodic table such as b to elements of Group 15 of the periodic table
Compound (or III-V compound semiconductor), Al₂S₃,
Al₂Se₃, Ga₂S₃, Ga₂Se₃, Ga₂Te₃, In
₂O₃, In₂S₃, In₂Se₃, In₂Te₃Periodic table number such as
Compound of Group 13 element and Group 16 element of the periodic table, TlC
Periodic table of the 13th group elements of the periodic table such as l, TlBr, and TlI
Compounds with Group 17 elements, ZnO, ZnS, ZnSe,
ZnTe, CdO, CdS, CdSe, CdTe, Hg
Periodic table group 12 elements such as S, HgSe, HgTe, etc.
Table Compounds with Group 16 elements (or II-VI group compounds)
Conductor), As₂S₃, As₂Se₃, As₂Te₃, Sb
₂S₃, Sb₂Se₃, Sb₂Te₃, Bi₂S₃, Bi₂S
e₃, Bi₂Te₃Periodic table group 15 elements and the periodic table first
Compound with Group 6 element, Cu₂O, Cu₂Periodic table such as Se
CuC, a compound of Group 11 element and Group 16 element of the periodic table
Periodic table of l, CuBr, CuI, AgCl, AgBr, etc.
NiO, a compound of Group 11 element and Group 17 element of the periodic table
Of periodic table group 10 elements and other periodic table group 16 elements
, Group 9 elements of the periodic table such as CoO, CoS and the first of the periodic table
Compound with Group 6 element, α-Fe₂O₃, Γ-Fe₂O₃, F
e₃O_FourOxides such as FeS, and elements of Group 8 of the periodic table such as FeS
Periodic Table Group 7 compounds such as compounds with Group 16 elements in the Periodic Table, MnO, etc.
Compounds of elements with elements of Group 16 of the periodic table, MoS₂, WO₂
Of periodic table group 6 element and other periodic table group 16 element
Thing, VO, VO₂, Ta₂O_FivePeriodic Table Group 5 elements such as
Compounds with Group 16 elements, TiO₂, Ti₂O_Five, T
i₂O₃, Ti_FiveO₉Titanium oxides such as rutile (crystal type is rutile
Type, rutile / anatase mixed crystal type, anatase type
It doesn't matter), ZrO₂Periodic table group 4 elements such as
Compounds with Group 16 elements in the periodic table, Y₂O₃, La₂O₃Circumference
Periodic Table Group 3 elements (including lanthanoid elements) and Periodic Table No.
Periodic table of compounds such as MgS, MgSe with group 16 elements
CdCr, a compound of Group 2 element and Group 16 element of the periodic table₂
O_Four, CdCr₂Se_Four, CuCr₂S_Four, HgCr₂Se_Four
Such as chalcogen spinel, or BaTiO₃Etc.
Can be mentioned. In addition, G. Schmid et al .; Adv. Ma
ter. , Vol. 4, p. 494 (1991).
(BN)₇₅(BF₂)₁₅F₁₅, D. Fenske
Angew. Chem. Int. Ed. Eng
l. , 29, p. 1452 (1990).
Cu ₁₄₆Se₇₃(Triethylphosphine)_{twenty two}like
Semiconductor clusters whose structure is well defined are also exemplified.
Be done.

Of these, those practically important are, for example, SnO ₂ , SnS ₂ , SnS, SnSe, SnTe, P.
Compounds of periodic table group 14 element and periodic table group 16 element such as bS, PbSe, PbTe, GaN, GaP, GaA
s, GaSb, InN, InP, InAs, III-V group compound semiconductor such as _{InSb, Ga 2 O 3, Ga} 2 S 3, Ga 2
Se ₃ , Ga ₂ Te ₃ , In ₂ O ₃ , In ₂ S ₃ , In ₂ S
e ₃ and In ₂ Te ₃ etc. Periodic Table Group 13 elements and Periodic Table 1
Compounds with Group 6 elements, ZnO, ZnS, ZnSe, Zn
Te, CdO, CdS, CdSe, CdTe, HgO,
II-VI group compound semiconductors such as HgS, HgSe, and HgTe, As ₂ O ₃ , As ₂ S ₃ , As ₂ Se ₃ , As ₂ Te ₃ , and S.
b ₂ O ₃ , Sb ₂ S ₃ , Sb ₂ Se ₃ , Sb ₂ Te ₃ , Bi
₂ O ₃ , Bi ₂ S ₃ , Bi ₂ Se ₃ , Bi ₂ Te ₃ and other compounds of periodic table group 15 element and periodic table group 16 element, α-Fe
₂ O ₃ , γ-Fe ₂ O ₃ , iron oxides such as Fe ₃ O ₄ and compounds of periodic table group 8 element such as FeS and periodic table group 16 element,
Compounds of periodic table group 4 elements and periodic table group 16 elements such as titanium oxides and ZrO ₂ described above, and periodic table group 3 elements (including lanthanoid elements) such as Y ₂ O ₃ and La ₂ O ₃ And a compound of Group 16 element of the periodic table.

Among these, SnO ₂ , GaN, Ga
P, In ₂ O ₃ , InN, InP, Ga ₂ O ₃ , Ga ₂ S ₃ ,
In ₂ O ₃ , In ₂ S ₃ , ZnO, ZnS, CdO, Cd
S, the above-mentioned iron oxides, rutile-type or anatase-type titanium dioxide, ZrO ₂ , Y ₂ O ₃ , MgS and the like do not contain a highly toxic negative element, and are therefore preferable in terms of environmental pollution resistance and safety to living organisms. From this viewpoint, SnO ₂ , In ₂ O ₃ , ZnO,
ZnS, α-Fe ₂ O ₃ , rutile titanium dioxide, ZrO
_A composition that does not contain a highly toxic positive element such as ₂ , Y ₂ O ₃ is more preferable.

Metal oxide semiconductor crystals such as ZnO, α-Fe ₂ O ₃ , rutile type titanium dioxide and Y ₂ O ₃ have a light absorption capacity
Since it has a high refractive index, safety and low cost, it is most preferable for applications such as an ultraviolet absorbing material and a high refractive index coating. In addition, colored semiconductor crystals having absorptivity in the visible region, such as iron oxides such as α-Fe ₂ O ₃ are important for coloring materials such as pigments.

In the case of utilizing the light emitting ability of semiconductor nanocrystals, GaN and Ga having an emission band in the visible region and its vicinity are used.
III-V group compound semiconductors such as P, GaAs, InN, InP, ZnO, ZnS, ZnSe, ZnTe, CdO,
II- such as CdS, CdSe, CdTe, HgO and HgS
Group VI compound semiconductors, In ₂ O ₃ , In ₂ S _3, etc. are important, and among them, ZnO, ZnS, ZnSe, ZnTe, CdO
It is a II-VI group compound semiconductor such as CdS or CdSe, and ZnO, ZnS, ZnSe, CdS, CdSe and the like are more preferably used for this purpose.

In the composition of any of the semiconductor crystals exemplified above, Al, Mn, Cu, Zn, A, etc. may be added as a trace amount of a doping substance (meaning impurities intentionally added) if necessary.
Elements such as g, Cl, Ce, Eu, Tb and Er may be added. The semiconductor nanocrystal according to the present invention is, for example, A. R. Kortan et al .; Am. Chem. So
c. 112, p. 1327 (1990) or US Pat. No. 5,985,173 (1999), a so-called core shell structure composed of an inner core (core) and an outer shell (shell) may be used. Together with the conductor shell described below, the semiconductor nanoparticles of the present invention having a two-layer shell structure will be provided.

In such a core-shell type semiconductor nanocrystal,
It may be suitable for applications using the exciton absorption / emission band. In this case, it is generally effective to form an energy barrier by using a semiconductor crystal composition of the shell having a band gap (band gap) larger than that of the core. It is presumed that this is due to a mechanism that suppresses the influence of an undesired surface level or the like due to the influence of the external environment or the crystal lattice defect on the crystal surface.

The composition of the semiconductor crystal preferably used for such a semiconductor shell depends on the band gap of the core semiconductor crystal, but the band gap in the bulk state has a temperature of 3 ° C.
Those having a voltage of 2.0 eV or more at 00K, for example, BN, BAs, III-V group compound semiconductors such as GaN and GaP, ZnO, ZnS, ZnSe, ZnTe, Cd.
II-VI group compound semiconductors such as O and CdS, MgS and MgS
A compound of a group 2 element of the periodic table and a group 16 element of the periodic table such as e is preferably used. Among these, the semiconductor crystal composition which is more preferable as the shell is a III-V group compound semiconductor such as BN, BAs, and GaN, ZnO, ZnS, and ZnS.
II-VI group compound semiconductors such as e and CdS, MgS, MgS
The band gap of the bulk state of the compound of the periodic table group 2 element such as e and the periodic table group 16 element is 2.3 eV or more at a temperature of 300 K, and BN, BAs, and GaN are most preferable. , ZnO, ZnS, ZnS
The bandgap of e, MgS, MgSe and the like in the bulk state is 2.5 eV or more at a temperature of 300 K, and ZnS is most preferably used in chemical synthesis.

A particularly preferred combination example of the core-shell composition used for the semiconductor nanocrystal of the present invention is expressed by a composition formula, CdSe-ZnS, CdSe-ZnO, CdS.
Examples thereof include e-CdS, CdS-ZnS, CdS-ZnO and the like. When the semiconductor nanoparticles of the present invention are used for the purpose of absorbing light in a specific wavelength range such as the ultraviolet region, the absorption edge wavelength of the absorption spectrum of the semiconductor nanocrystals constituting the core may be in the range of 300 to 600 nm. preferable. The lower limit of the range of the absorption edge wavelength is more preferably 330 nm, further preferably 370 nm for the purpose of absorbing the ultraviolet region that deteriorates the organic matrix such as synthetic resin, while the upper limit is the transparency in the visible region. From the viewpoint, it is more preferably 550 nm, further preferably 500 nm,
Most preferably, it is 450 nm.

[Manufacturing Method of Semiconductor Nanocrystal] The manufacturing method of the semiconductor nanocrystal is not limited, but the following three liquid phase methods are exemplified. (1) A method of allowing a raw material aqueous solution to exist as a reverse micelle in a non-polar organic solvent and growing crystals in the reverse micelle phase (hereinafter referred to as "reverse micelle method"). S. Zou
Int. J. Quant. Chem. , Volume 72, 4
39 (1999). A well-known reverse micelle stabilization technology can be used in a general-purpose reaction kettle, a relatively inexpensive and chemically stable salt can be used as a raw material, and it is performed at a relatively low temperature that does not exceed the boiling point of water. This method is suitable for production. However, the current state of the art may be inferior to the light emission characteristics as compared with the case of the hot soap method described below. (2) A method of injecting a thermally decomposable raw material into a high temperature liquid-phase organic medium for crystal growth (hereinafter referred to as a hot soap method), for example, the method described in J. E. B. This is the method reported in the literature by Katari et al. Compared with the reverse micelle method, semiconductor crystal particles having an excellent particle size distribution and purity can be obtained, and the product has excellent light emitting characteristics and is usually soluble in an organic solvent. In order to desirably control the reaction rate of the crystal growth process in the liquid phase in the hot soap method, a coordinating organic compound having an appropriate coordinating force for a semiconductor constituent element is used as a liquid phase component (also serves as a solvent and a ligand). ) Is selected as. Examples of the coordinating organic compound include the trialkylphosphines, the trialkylphosphine oxides, ω-aminoalkanes such as dodecylamine, tetradecylamine, hexadecylamine, and octadecylamine. Of these, preferred are trialkylphosphine oxides such as TOPO and ω-aminoalkanes such as hexadecylamine. (3) A method suitable for industrial production in which a semiconductor crystal or a precursor thereof is generated at a relatively low temperature of about 100 ° C. or lower in a protic solvent such as water or ethanol by using an acid-base reaction as a driving force (hereinafter referred to as “sol. -"Gel method"). For example, a synthesis example of titanium oxide nanocrystals is Seijiro Ito et al .; Coloring Material, Vol. 57, No. 6, 305-308 (1984).
A synthetic example of zinc oxide nanocrystals is described in L. et al. Spanhel
J. et al. Am. Chem. Soc. , Volume 113, 282
Each is reported on page 6 (1991). Examples of suitable raw materials in the sol-gel method include titanyl sulfate for the synthesis of titanium oxide nanocrystals, and zinc salts such as zinc acetate and zinc nitrate for the synthesis of zinc oxide nanocrystals. Tetraethyl orthosilicate (abbreviation TEO)
Metal alkoxides such as S) and tetraisopropoxy orthotitanate can also be preferably used as a raw material. In particular, in the case of synthesizing oxide nanocrystals by the sol-gel method, for example, as in the synthesis of titanium oxide nanocrystals using titanyl sulfate as a raw material, a precursor such as hydroxide is used, and then acid or alkali (preferably It is also possible to use dehydration condensation or deflocculation of this to form a hydrosol. In the procedure via such a precursor, it is preferable in terms of purity of the final product to isolate and purify the precursor by an arbitrary method such as filtration or precipitation separation (centrifugation if necessary). A suitable surfactant such as sodium dodecylbenzene sulfonate (abbreviated as DBS) may be added to the hydrosol to make the sol particles (that is, the nanoparticles of the semiconductor or its precursor) water-insoluble and then isolated.

[Conductor Shell] The conductor which constitutes the shell in the semiconductor nanoparticles of the present invention has an electric conductivity σ of 1,000 S / c in a bulk state at a temperature of 300K.
It is a substance of m or more, and its electric conductivity value is preferably 10,000 S / cm or more, more preferably 10
It is at least 10,000 S / cm. Examples of the substance of such a conductor are represented by transition metals such as gold, platinum, silver, palladium, rhodium, zinc, copper, nickel and iron, alloys of these transition metals, graphite, carbon black and C _60. Examples thereof include carbon materials such as fullerenes and carbon nanotubes, and conductive inorganic substances such as barium titanate. Among these conductors, those preferably used in order to form a conductor shell with a uniform and controlled film thickness are copper, simple transition metals of the fifth and sixth periods of the periodic table, that is, gold, platinum, silver. , Palladium and the like, and among them, silver, copper, gold, platinum and the like are more preferable in terms of conductivity, chemical stability, and easiness of binding surface-modifying molecules to be described later, and most preferable is silver. Alloys of these transition metals are also preferably used for the same reason.

The conductor shell does not necessarily completely cover the surface of the semiconductor nanocrystal core,
Such coverage is usually 50% of the surface of the semiconductor nanocrystal core.
The above is preferably 70% or more, more preferably 90% or more. The coverage is determined by combining the TEM observation and analysis techniques such as surface elemental analysis. If this coverage is too small, the effect of reducing the photocatalytic activity may be insufficient.

There is no limitation on the purity of the chemical composition of the conductor shell as long as it exerts the effect of diminishing the photocatalytic activity of the semiconductor nanocrystal core, and it may be, for example, an alloy of two or more kinds of metals. In the case of a transition metal shell, the surface thereof may contain a chalcogenide composition such as an oxide or a sulfide. As particularly suitable semiconductor nanoparticles, titanium oxides (for example, rutile-type or anatase-type titania) and zinc oxide having excellent ultraviolet absorption ability are used as cores,
Examples thereof include those having a transition metal shell such as silver and gold having excellent electrical conductivity and chemical stability.

[Method for Forming Conductor Shell] There is no limitation on the method for forming the above-mentioned conductor shell on the surface of the semiconductor nanocrystal core, but a typical conductor shell of transition metal such as gold or silver is used. For example, it can be formed by a reaction of adding a reducing agent or the like in the metal salt aqueous solution which is the chemical plating method or the pretreatment method thereof described in the above-mentioned prior art to reduce a metal cation and generate a zero-valent metal. For example, chloroauric acid or a salt thereof (for example, sodium chloroaurate), silver nitrate, silver perchlorate, a transition metal ion compound such as copper chloride or a salt thereof, citric acid or a salt thereof (for example sodium citrate), tartaric acid or By a reduction reaction in which the salt (for example, sodium tartrate), a borohydride salt such as sodium borohydride or lithium borohydride, an aldehyde such as acetaldehyde or formaldehyde, or an alcohol such as ethanol or methylcellosolve is contacted. It is possible. Such reduction reaction may be accelerated by irradiation with light.

The reduction reaction is preferably carried out in a protic solvent such as water, methanol, ethanol, propanol or butanol, and a hydrophobic organic solvent such as toluene or xylene may coexist therewith. Two or more kinds of solvents may be mixed and used. Such a solvent may also serve as the reducing agent. Among these solvents, alcohols having 3 or less carbon atoms such as methanol, ethanol, n-propanol, and isopropyl alcohol, and water are preferable from the viewpoint of solubility of raw materials. When the reduction reaction is carried out in an aqueous phase, it is necessary to use an organic solvent such as toluene or hexane which is immiscible with water.
Alternatively, the surface modification molecule may be dissolved in the organic solvent, and the surface modification molecule may be extracted into the organic phase while being bound to the surface of the core-shell type particle by a two-phase interfacial reaction.

The temperature condition of the reduction reaction is usually 0 to 1
It is about 00 ° C., and is preferably 10 from the viewpoint of reaction controllability.
-80 degreeC, More preferably, it is about 20-60 degreeC. On the other hand, the reaction time is usually 1 minute to 24 hours, preferably 5 minutes to 12 hours, and more preferably 10 minutes to 6 hours. [Surface-modifying molecule] The surface-modifying molecule in the semiconductor nanoparticles of the present invention is an organic molecule bonded to the surface of a core-shell type particle composed of a semiconductor nanocrystal core and a conductor shell, and is a secondary molecule of the core-shell type particle. It mainly exhibits the effect of preventing aggregation and the effect of imparting dispersibility to a desired organic matrix such as a resin. There is no limitation on the structure of the surface-modifying molecule as long as it exerts such an effect, but a carbon-carbon double bond, a carbon-carbon triple bond, a carbonyl group (ester bond, amide bond, carbonate bond, urethane bond, urea bond, (Including ketone group), ether bond, carboxyl group, acid anhydride group, amino group, hydroxyl group,
It is preferable to have at least one chemical structure arbitrarily selected from the group consisting of an epoxy group and an aliphatic ring (hereinafter, such a chemical structure is referred to as “matrix affinity structure”) in its molecular structure.

The matrix-affinity structure exemplified here is a chemical reaction with an organic matrix such as a resin, a chemical reaction with a precursor of the organic matrix (for example, a polymerizable monomer) (for example, copolymerization), or with the organic matrix. Physicochemical affinity (for example, relatively strong chemical bond such as coordination bond or ionic bond, hydrogen bond, hydrophobic-hydrophobic interaction, π electron interaction, relatively weak attractive interaction such as van der Waals force) The above mechanism imparts affinity between the core-shell type particles and an organic matrix such as a resin. Among these exemplified matrix affinity structures, carbon-carbon double bond, ester bond, carboxyl group, acid anhydride group, amino group, hydroxyl group and epoxy group are preferable from the viewpoint of chemical reactivity, and among them, carbon-carbon. The double bond is particularly useful in terms of copolymerizability with important radically polymerizable monomers such as methyl methacrylate and styrene, and the ester bond, the carboxyl group, the hydroxyl group and the epoxy group are bisphenol A polycarbonate resin (PC resin) or Chemical reactivity with transparent resins containing ester groups such as polymethylmethacrylate resin (PMMA resin) or some amorphous polyolefin resins in the molecular structure (for example, transesterification reaction and opening of epoxy groups by polymer end groups). It is particularly useful in terms of ring reaction).

The above-mentioned aliphatic ring is a hydrocarbon cyclic structure composed only of non-aromatic carbon atoms, and is composed of an arbitrary number of ring units such as a monocyclic ring, a bicyclic ring or a polycyclic ring such as a tricyclo ring. It is composed. Such an aliphatic ring is
It has excellent compatibility with a highly hydrophobic transparent resin matrix such as an amorphous polyolefin resin. The above-mentioned aliphatic ring has a hydrogen atom which has an arbitrary substituent (for example, an alkyl group such as a methyl group or an ethyl group, a phenyl group, etc.) as long as the compatibility with a highly hydrophobic transparent resin matrix is not extremely impaired. Aryl group, alkoxy group such as methoxy group, aryloxy group such as phenoxy group, hydroxyl group, amino group, carboxyl group, ester group, amide group, acid anhydride group, nitrile group, carbonyl group, etc.) Good. The number of carbon atoms contained in the aliphatic ring is
As a carbon atom constituting the ring structure excluding the above-mentioned substituents, it is usually 3 to 10, and preferably 5 to 1 from the viewpoint of chemical stability.
0, more preferably 5 to 9 and still more preferably 5 to 7 in terms of compatibility with a highly hydrophobic transparent resin matrix. Specific examples include a monocyclic structure such as a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring and a cyclooctane ring, an adamantane ring, a noradamantane ring, a norbornane ring, a norbornene ring, a dicyclopentadiene ring and the like. And the like. Among them, preferred are the monocyclic structures such as cyclopentane ring and cyclohexane ring, and the polycyclic structures such as noradamantane ring and norbornane ring.

The surface-modifying molecule used in the present invention has a chemical structure (hereinafter referred to as “particle-bonding structure”) that binds to the surface of the core-shell type particle together with the above-mentioned matrix-affinity structure. The particle binding structure is not limited, and the binding mode is also not limited. For example, a nitrogen-containing functional group such as an amino group, a pyridine ring and a nitrile group, a mercapto group (or a thiol group), a methylsulfide group (-SC
H _3), methyl disulfide group _{(-S-S-CH 3)} , thio groups (-COSH), dithio group (-CSSH), xanthate, xanthate group, isothiocyanate group, thiocarbamate group, and a thiophene ring Sulfur-containing functional groups such as, carboxyl group, sulfonic acid group, phosphonic acid group, phosphinic acid group, acidic group such as phosphonic acid partial ester group and phosphinic acid partial ester group, carboxylic acid amide group, sulfonic acid amide group, phosphonic acid Amido group such as amide group and phosphinic acid amide group, salt of acidic group such as carboxylate group, sulfonate group, phosphonate group and phosphinate group, and three phosphorus-carbon bonds such as phosphine group and phosphine oxide group Examples thereof include a group and a hydroxyl group. Among these, preferably used in terms of binding to the transition metal shell, amino group, nitrogen-containing functional group such as pyridine ring, sulfur-containing functional group such as mercapto group,
An acid group such as a carboxyl group, a sulfonic acid group and a phosphonic acid group, and a group having three phosphorus-carbon bonds such as a phosphine group and a phosphine oxide group, and among them, a mercapto group, an amino group, a phosphonic acid group, a phosphine group and a phosphine The oxide group is more preferable, the mercapto group, the amino group and the phosphonic acid group are further preferable, and the mercapto group is most preferably used from the viewpoint of the coordination power to the transition metal element.

Specific examples of the surface modifying molecule are shown below. (1) Compound having a mercapto group as a particle-bonding structure ... Alkanethiols such as 1-mercaptobutane, 1-mercaptooctane, 1-mercaptododecane and mercaptocyclohexane, arylthiols such as thiophenol and 4-hydroxythiophenol Mercapto fatty acids such as mercaptoacetic acid, 3-mercaptopropanoic acid and 11-mercaptoundecanoic acid, mercaptoalcohols such as 2-mercaptoethanol and 6-mercapto-1-hexanol, and 1-amino-2-mercaptoethane Compounds having an amino group and a mercapto group, compounds having an amino group such as cysteine, a carboxyl group and a mercapto group, 3-mercaptopropanoic acid glycidyl ester and 11-mercaptoundecanoic acid glycidyl ester Compounds having an epoxy group and a mercapto group, such as glycidyl esters of mercapto fatty acids, 3-mercapto propanoic acid vinyl ester and 1
Vinyl esters of mercapto fatty acids such as 1-mercaptoundecanoic acid vinyl ester, allyl esters of mercapto fatty acids such as 3-mercaptopropanoic acid allyl ester and 11-mercaptoundecanoic acid allyl ester, 3-mercaptopropanoic acid triethylene glycol Polyalkylene glycol esters of mercapto fatty acids such as monomethyl ether ester, 11-mercaptoundecanoic acid triethylene glycol monomethyl ether ester and 11-mercaptoundecanoic acid triethylene glycol ester, or 4- (mercaptomethyl) vinylbenzene or 2-mercapto Compounds having a carbon-carbon double bond such as ethyl methacrylate and a mercapto group. 1H, 1H, 2H, 2H-perfluorooctyl-1-thiol, 1H, 1H, 2H,
2H-perfluorodecyl-1-thiol, 1H, 1
1H, 1H, 2H, 2H-perfluoroalkyl- such as H, 2H, 2H-perfluorododecyl-1-thiol
1-thiols, 1H, 1H, 2H, 2H-perfluorodecanol 3-mercaptopropanoic acid ester, 1
11 of H, 1H, 2H, 2H-perfluorobutanol
-Mercaptoundecanoic acid ester, 1H, 1H, 2
1 of mercapto fatty acids such as 11-mercaptoundecanoic acid ester of H, 2H-perfluorododecanol
A compound having a fluorinated alkyl group such as H, 1H, 2H, 2H-perfluoroalkyl-1-ol esters and a mercapto group can be converted into a fluorine atom-containing polymer such as poly (perfluoroethylene) (trade name Teflon). It is preferably used when imparting the compatibility of. (2) A compound having an amino group as a particle-bonding structure ...
Ω-aminoalkanes such as 1-aminohexane, 1-aminododecane and 1-aminohexadecane, aminoalkanes having an aliphatic ring such as cyclohexylamine, laromine and isophoronediamine, 2-aminoethanol,
Compounds having a hydroxyl group and an amino group such as diethanolamine and tris (hydroxymethyl) aminomethane, 4
-Vinylaniline, 2-aminoethylmethacrylate,
Carbon such as monomaleimide of 1,6-diaminohexane
Compounds having a carbon double bond and an amino group, 6-aminohexanoic acid, 12-aminododecanoic acid, compounds having a carboxyl group such as α-amino acid (eg, arginine and lysine) and an amino group, 6-aminohexanoic acid Compounds having an epoxy group and an amino group, such as glycidyl ester and 12-aminododecanoic acid glycidyl ester. (3) Compounds having a phosphonic acid group as a particle-bonding structure: n-butylphosphonic acid, n-hexylphosphonic acid, dodecylphosphonic acid, hexadecylphosphonic acid and other chain alkylphosphonic acids, cyclohexylphosphonic acid, cyclohexylmethylphosphonic acid Alkylphosphonic acids having aliphatic rings such as acids, p-butylphenylphosphonic acid, p-hexylphenylphosphonic acid, phenylphosphonic acids having chain alkyl groups such as p-dodecylphenylphosphonic acid, p-cyclohexylphenylphosphonic acid Such as phenylphosphonic acids having an aliphatic ring, hydroxymethylphosphonic acids, alkylphosphonic acids having a hydroxyl group such as 1-hydroxyethylphosphonic acid, (4-vinylphenoxy) methylphosphonic acid, phosphonomethylacrylate, phosphono Carbon atoms, such as chill methacrylate -
Alkylphosphonic acids having a carbon double bond, glycidyloxymethylphosphonic acid and 1- (glycidyloxy)
Alkylphosphonic acids having an epoxy group such as ethylphosphonic acid.

[Resin Composition] The resin composition of the present invention is a matrix resin described below in which the semiconductor nanoparticles of the present invention are dispersed, and the semiconductor nanoparticles are 0.01 in terms of ash content.
-80% by weight. There is no limitation on the dispersion state of the semiconductor nanoparticles in the resin composition, but preferably, as the transparency of the resin composition, the light transmittance at an optical path length of 50 μm is 70% or more in the incident light wavelength range of 450 to 650 nm. .

If the ash content is too small, the properties of the semiconductor in the resin composition (for example, light absorption and emission characteristics, high refractive index, non-water absorption, non-gas permeability, hydrolysis resistance, heat decomposition resistance, heat deformation). Properties, flame retardancy, surface hardness, high elastic modulus, etc.) are hardly reflected, so the lower limit of the ash content is preferably 0.1% by weight, more preferably 1% by weight. On the other hand, if the ash content is too large, the mechanical properties of the resin composition (particularly the toughness such as impact resistance) may be extremely deteriorated, so the upper limit of the ash content is preferably 70% by weight, It is preferably 60% by weight. The above ash content is
600 given resin composition in a nitrogen atmosphere at atmospheric pressure
Calculated from the residue obtained by heating to ℃.

If the light transmittance is too small, it may cause inconvenience in applications requiring transparency such as optical members and films. Therefore, a larger value is desirable, preferably 80% or more, and more preferably 85. % Or more. The matrix resin used in the resin composition is a polymer material that forms a continuous phase in which the semiconductor nanoparticles are dispersed. The type is not limited, but an amorphous resin is preferably used in applications requiring transparency. The amorphous resin in the present invention is a resin material having a light transmittance of 80% or more of sodium D rays in an optical path length of 3 mm,
It may be a single composition or a mixture of plural kinds of polymers (so-called polymer alloy).

Specific examples of such an amorphous resin include, as the thermoplastic resin, an acrylic resin containing acrylic acid ester or methacrylic acid ester as a main monomer component (for example, polymethylmethacrylate or abbreviated PMMA), bisphenol. Aromatic polycarbonate resin containing bisphenols represented by A and a carbonic acid derivative (for example, phosgene, diphenyl carbonate, etc.) as monomer main components (abbreviated as P
C), a styrene-based resin containing styrene as a monomer main component (for example, polystyrene or abbreviated as PS), and an amorphous polyolefin resin containing a vinyl compound having an aliphatic ring as a monomer main component (for example, Arton, Apel, Zeonex). (Trademarks known to those skilled in the art) and the like. Examples of the crosslinkable resin include a thermosetting resin that is cured using a thermal polymerization initiator and a photocurable resin that is cured using a photopolymerization initiator.The chemical composition of the crosslinkable resin is acrylic. Examples thereof include acrylic curable resins containing acrylic acid derivatives such as acid esters and methacrylic acid esters as a monomer main component, and epoxy curable resins obtained by ring-opening polymerization of epoxy groups. Among these, aromatic polycarbonate resin is preferable in terms of heat distortion resistance,
An amorphous polyolefin resin and the above crosslinkable resin,
Amorphous polyolefin resins are more preferable in that the dimensional change in water absorption is small. PMMA resin is preferable from the viewpoint of light transmittance, but since the glass transition point is about 100 ° C., acrylic having improved heat distortion resistance by copolymerizing a monomer having an ester group with greater steric hindrance. A system resin can also be used.

The resin composition of the present invention may contain any additives such as heat stabilizers, antioxidants, light absorbers, coloring agents such as dyes and pigments, and plasticizers, as long as they do not significantly deviate from the object of the present invention. Agents, mold release agents, flame retardants, antistatic agents, reaction initiators, etc., or arbitrary fillers such as glass fibers, glass flakes, glass powder, hollow glass spheres, porous silica, silica having nanopores, talc, montmorillonite Clay minerals represented by, metal powders, metal fibers, metal whiskers, ceramic powders, ceramic whiskers, carbon fibers, carbon black, graphite, carbon nanotubes and the like may be mixed.

[Production Method of Resin Composition] Although the production method of the resin composition of the present invention is not limited, for example, a method of melt mixing or solution mixing the semiconductor nanoparticles and the matrix resin, Examples thereof include a method of first mixing with a polymerizable monomer forming a matrix resin and then polymerizing the monomer (hereinafter referred to as “internal addition polymerization method”).

For the melt mixing, a known melt mixing apparatus such as a single screw extruder, a twin screw extruder, a Brabender, a roll can be used. Such melt mixing may be performed by preparing a master batch in advance. The solution mixing is performed by dispersing (preferably dissolving) the semiconductor nanoparticles in a solution of the matrix resin used, and then removing the solvent. The solvent used at this time is preferably a common solvent for the matrix resin and the semiconductor nanoparticles. When the representative amorphous resin is used, for example, an ether solvent such as tetrahydrofuran (abbreviated as THF), a halogen solvent such as methylene chloride or chloroform, an amide such as N, N-dimethylformamide or N-methylpyrrolidone. A system solvent, an aromatic solvent such as toluene, xylene, chlorobenzene, or chloronaphthalene is preferably used. The solvent is removed by, for example, a method such as distillation or evaporation by vaporizing the solvent, a reprecipitation method by adding the solution into a solvent that does not dissolve the matrix resin, or the like.

The internal polymerization method may be carried out by any polymerization method (eg, radical polymerization, anionic polymerization, cationic polymerization, coordination polymerization, ring-opening polymerization, condensation polymerization, etc.). The polymerizable monomer used is not particularly limited as long as the solubility and dispersibility are not extremely deteriorated. If necessary, a non-polymerizable solvent may be added to carry out the polymerization. As the polymerizable monomer suitable for the internal addition polymerization method, for example, a linear polymer such as methyl methacrylate or styrene that gives a linear polymer, or a combination of bisphenol A and a carbonic acid derivative (for example, phosgene or diphenyl carbonate) is used. As described above, which gives an aromatic polycarbonate resin by an interfacial polymerization method (for example, methylene chloride / water system) or a melt polymerization method, and a bis (meth) having an alicyclic skeleton represented by the following general formula (1) as a crosslinkable monomer. ) Acrylates and (meth) acrylates having a sulfur atom represented by the following general formula (2) are exemplified. When performing the above radical polymerization, a thermal radical initiator and / or a photo radical initiator is usually used as a radical initiator.

[0048]

[Chemical 1]

However, in the general formula (1), R ^a and R ^b
Each independently represent a hydrogen atom or a methyl group, R ^c and R ^d each independently represent an alkylene group having 6 or less carbon atoms, x represents 1 or 2, and y represents 0 or 1. .

[0050]

[Chemical 2]

However, in the general formula (2), R ^a and R ^b
Is the same as in the case of the general formula (1), R ^e is an alkylene group having 1 to 6 carbon atoms, and Ar is 6 to 6 carbon atoms.
An arylene group or an aralkylene group which is 30, or a group in which a hydrogen atom is replaced with a halogen atom except fluorine, X represents an oxygen atom or a sulfur atom,
Regarding Y, when X is an oxygen atom, a sulfur atom or a sulfonyl group (—SO ₂ —) is used, and when X is a sulfur atom, a sulfur atom, a sulfonyl group, a carbonyl group (—CO—), or a carbon number is 1 to 12 represents an alkylene group, an aralkylene group, an alkylene ether group, an aralkylene ether group, an alkylene thioether group, or an aralkylene thioether group, and j and p each independently represent an integer of 1 to 5, k represents an integer of 0 to 10, respectively. When k is 0, X represents a sulfur atom.

[Thin Film Molded Product] The thin film molded product comprising the resin composition of the present invention and having a film thickness of 0.05 to 3000 μm is, for example, an optical panel excellent in light resistance or a light absorbing coating layer for ultraviolet rays and the like. Is useful as The lower limit of the film thickness is preferably 0.1 μm, more preferably 0.5 μm in terms of mechanical strength and light absorption ability. on the other hand,
The upper limit of the film thickness is preferably 2000 μm, more preferably 10 μm, in view of moldability and cost-effectiveness balance of the thin film.
It is 00 μm.

Such a thin-film molded product is usually in the form of a film or a thin plate (that is, a sheet), and depending on the application, paper pulp, wood, resin, organic crystals, diamond, glass,
It is molded in close contact with any solid material substrate such as ceramics, inorganic crystals, metals, and semiconductors. The thin film shaped product of the present invention does not necessarily have to be flat, and is formed on a substrate of any shape such as a spherical shape, an aspherical curved surface shape, a cylindrical shape, a conical shape, or a bottle shape such as a PET bottle. It doesn't matter. Further, the thin-film molded body made of a flexible substrate such as paper pulp, wood, or resin may be physically deformed by bending, stretching, compressing or the like before or after the molding operation.

If necessary, the thin film-shaped molded product may have a layer for coating the coating surface, for example, a protective layer for preventing mechanical damage to the coating surface due to friction or abrasion, a cause of deterioration of semiconductor crystal particles, a base material or the like. A light absorbing layer that absorbs light having an undesired wavelength, a transmission blocking layer that suppresses or prevents the transmission of reactive low molecules such as water and oxygen gas, an antiglare layer, an antireflection layer,
A multilayer structure may be provided by providing an optional additional functional layer such as a low refractive index layer or the like, an undercoat layer for improving the adhesiveness between the base material and the coated surface, an electrode layer or the like.

[0055]

EXAMPLES Specific examples of the present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples as long as the gist thereof is not exceeded. [Measuring device] (1) Transmission electron microscope (TEM): Hitachi, Ltd.
H-9000UHR transmission electron microscope (accelerating voltage 3
00kV, vacuum degree during observation: 7.6 × 10 ^-9 Tor
r). (2) Absorption spectrum: Hewlett Packard H
P8453 UV / Visible absorptiometer.

[Synthesis Example of Semiconductor Nanocrystals] Synthesis Example 1: Zinc oxide nanocrystals Commercially available zinc nitrate hydrate (1 equivalent) is dispersed in ethanol, and heated under reflux at atmospheric pressure with stirring under a dry nitrogen atmosphere. Was carried out for 3 hours. Then, the concentrated liquid obtained by distilling off a part of the solvent at atmospheric pressure is dried under a nitrogen atmosphere to
It was cooled to about -5 ° C. Lithium hydroxide monohydrate (1 equivalent) was added to this, and most of the lithium hydroxide monohydrate was dissolved by irradiating with ultrasonic waves while gently shaking in an ultrasonic cleaner containing ice water, and further. When stirring was continued in an ice bath for 30 minutes to completely dissolve lithium hydroxide monohydrate, a transparent ethanol sol was obtained. When this ethanol sol was diluted with ethanol and the absorption spectrum was measured, the absorption spectrum of a ZnO crystal having a peak near 320 nm was given. From the wavelength of the absorption peak, the number average particle size of the obtained ZnO nanocrystals was estimated to be about 3.5 nm.

Synthetic Example 2: Titanium Oxide Nanocrystal The method described in the literature by Seishiro Ito et al. Was used as a reference. The procedure will be described below. While stirring an aqueous solution of titanyl chloride having a concentration of 0.1 mol / L, the same volume of an aqueous solution of sodium carbonate having a concentration of 1.5 mol / L was added dropwise at room temperature over 25 minutes. The thus-obtained suspension of white ultrafine particles was purified by an operation in which three steps of centrifugation (4000 rpm), removal of the supernatant by decantation, and washing with water were repeated in this order. However, the purification was carried out until the white turbidity of barium sulfate was not visually observed even if an aqueous barium hydroxide solution was added to the supernatant. The white precipitate thus obtained was stirred and dispersed in dilute hydrochloric acid having a concentration of 0.3 mol / L and heated at 60 ° C. for about 1 hour to obtain a transparent acidic hydrosol.

This acidic hydrosol was ice-cooled, and an aqueous solution of sodium dodecylbenzenesulfonate (abbreviated as DBS) (concentration of 0.05 mol / L) was added. As a white precipitate was formed, this was extracted with toluene and concentrated. . The TEM observation of this concentrated residue revealed that the titanium oxide nanocrystals contained in the titanium oxide hydrosol had a number average particle size of 5 nm.
I found out.

The above acidic hydrosol is diluted with ethanol and then contacted with an anion exchange resin to remove and purify chloride ions to obtain a titanium oxide hydrosol. [Synthesis of Surface Modification Molecule] Synthesis Example 3: 6-mercapto-1-supplied from ω-mercaptohexyl methacrylate Aldrich.
Methacrylic acid was added to hexanol to give a catalytic amount of 2,6-
Di-t-butyl-4-methylphenol was added as a radical inhibitor, and further a catalytic amount of concentrated sulfuric acid was added to the mixture to accelerate dehydration esterification by heating under reduced pressure, and 6'-mercapto-n- which was the target product. Hexyl methacrylate (hereinafter abbreviated as MHM) is generated. Purification of MHM is performed by silica gel column chromatography, and the presence of ester groups is confirmed by infrared absorption spectrum.

[Synthesis of Semiconductor Nanoparticles Having a Metal Shell] Example 1: Zinc Oxide Nanoparticles having a Silver Shell To the ethanol sol containing the zinc oxide nanocrystals of Example 1, an ethanol solution of silver nitrate was added to obtain metallic silver. A reduction reaction is performed to obtain a dispersion liquid of zinc oxide nanocrystals having a silver shell. The MHM obtained in Synthesis Example 3 is added thereto as a surface-modifying molecule to obtain zinc oxide nanoparticles having a silver shell coated with MHM (hereinafter abbreviated as MHM-Ag-ZnO). Purification of MHM-Ag-ZnO was performed by washing the extract solution with toluene in which this was dissolved, then throwing it into methanol, centrifuging the precipitate obtained, dissolving it again in toluene, and re-dissolving this toluene in methanol again. Perform by re-precipitation. A desired degree of purification is obtained by repeating such redissolution and reprecipitation.

[Resin Composition] Example 2: Acrylic Cross-Linked Resin Composition Under dimming conditions, the bifunctional acrylate of formula 3 (94% by weight) was mixed with MHM-Ag-ZnO (5% by weight) obtained in Example 1. %) And 2,4,6-trimethylbenzoyldiphenylphosphine oxide (1% by weight) as a photo-radical initiator were dissolved under light-shielding conditions, and then poured into a gap between glass plates with a spacer having a thickness of 0.1 mm. When exposed and photocured, a thin film-shaped molded product of a transparent crosslinked resin composition is obtained. This thin film-shaped molded product retains the ultraviolet absorbing property of the zinc oxide nanocrystals contained therein.

[0062]

[Chemical 3]

Example 3: PMMA resin composition Mmethacrylate (89% by weight) was added to MHM-Ag-ZnO (10% by weight) obtained in Example 1 and N, N'-azobisisobutyi as a thermal radical initiator. Ronitrile (1
(% By weight), and then poured into a gap between glass plates with a spacer having a thickness of 3 mm and then heated to 70 ° C. to obtain a transparent thin PMMA resin composition having a thickness of 3 mm. This thin film-shaped molded product retains the ultraviolet absorbing property of the zinc oxide nanocrystals contained therein.

[0064]

Since the core-shell type semiconductor nanoparticles of the present invention have the conductor shell on the surface of the semiconductor nanocrystal core, the photocatalytic ability of the semiconductor crystal surface is remarkably reduced. Therefore, when the semiconductor nanoparticles of the present invention are dispersed in an organic matrix such as a synthetic resin, decomposition of the organic matrix due to the photocatalytic ability is extremely suppressed. Moreover, since the semiconductor nanoparticles of the present invention have surface-modifying molecules bound to their surfaces, the dispersibility in an organic matrix is extremely good. Due to the characteristics of the photocatalytic activity and the dispersibility in the organic matrix, the transparent resin composition in which the semiconductor nanoparticles of the present invention are dispersed has a high light resistance such as ultraviolet absorption and high refractive index which are the characteristics of the semiconductor. Since it is provided, it is used as a component material for optical devices such as projectors and displays.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H048 CA05 CA13                 4J037 AA02 AA04 AA08 AA11 AA12                       AA15 AA22 CA02 CA03 CA14                       CB16 CB21 CB22 CB26 DD05                       DD13 EE04 EE18 EE19 EE28                       EE43 FF02 FF15 FF22

Claims (9)

[Claims] 1. A core-shell type semiconductor nanoparticle in which a surface-modifying molecule is bonded to the surface of a core-shell type particle composed of a semiconductor nanocrystal core and a conductor shell and having a number average particle size of 2 to 50 nm. 2. The absorption edge wavelength of the absorption spectrum is 300 to
The core-shell type semiconductor nanoparticles according to claim 1, which are in the range of 600 nm. 3. The core-shell type semiconductor nanoparticles according to claim 1, wherein the semiconductor nanocrystal core is a metal oxide. 4. The core-shell type semiconductor nanoparticles according to claim 1, wherein the conductor shell is a transition metal simple substance or an alloy. 5. The surface-modifying molecule is a carbon-carbon double bond,
At least one selected from the group consisting of carbon-carbon triple bond, carbonyl group, ether bond, carboxyl group, acid anhydride group, amino group, hydroxyl group, epoxy group and aliphatic ring.
The core-shell type semiconductor nanoparticles according to any one of claims 1 to 4, which have different chemical structures. 6. The core-shell type semiconductor nanoparticle according to claim 1, wherein the surface modification molecule has a group selected from a mercapto group, an amino group, a phosphonic acid group, a phosphine group and a phosphine oxide group. particle. 7. A resin composition containing the semiconductor nanoparticles according to claim 1 in an ash content of 0.01 to 80% by weight. 8. The resin composition according to claim 7, wherein the light transmittance in an optical path length of 50 μm is 70% or more in an incident light wavelength range of 450 to 650 nm. 9. A thin-film molded body comprising the resin composition according to claim 8 and having a film thickness of 0.05 to 3000 μm.