JP2002020740A - Semiconductive crystal ultrafine particle having ligand with hyperbranched structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide semiconductive crystal ultrafine particles excellent in solubility to a medium, uniform thin film formability and chemical stability owing to screening effect from the outside, and having controlled extinction or luminescent properties owing to its quantum effect. SOLUTION: The semiconductive crystal ultrafine particles are such that a hyperbranched molecule is bound at its focal point thereto as the ligand having preferably a dendrimer structure (especially polybenzyl ether dendrone); wherein the focal point functional group contain preferably a phosphorus or sulfur atom, and the semiconductor crystal contain preferably at least one of group 12 to 17 elements.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to ultrafine semiconductor crystal particles. More specifically, the present invention relates to ultrafine semiconductor crystal particles that are excellent in solubility and dispersibility in a medium such as various solvents and polymers and in uniform thin film formation, and are also excellent in chemical stability. The ultrafine particles of the present invention may have controlled absorption or emission characteristics due to the quantum effect, giving an ultra-high-density recording material using optical characteristics, or an optical material used as a light-emitting element or an optical waveguide, It is used in fields such as information, communication, optical computers, and fluorescence diagnostics.

[0002]

2. Description of the Related Art As a method for producing ultrafine semiconductor crystal particles,
Conventional vacuum manufacturing processes such as molecular beam epitaxy (MBE), metalorganic vapor phase epitaxy (MOVPE),
Alternatively, an atomic layer epitaxy method (ALE method) or the like may be used. Although a product of high purity can be obtained by such a vacuum manufacturing process, the ultrafine particles generated can be obtained only in a state of being firmly adhered to the substrate, and cannot be freely dispersed and used in a medium such as a solvent or a polymer.

On the other hand, in recent years, there have been many reports on ultrafine semiconductor crystal particles having controlled absorption or emission characteristics by the quantum effect. For example, C.I. B. Murr
ay et al .; Am. Chem. Soc. , 115, 8
On page 706 (1993), semiconductor crystal ultrafine particles having excellent solubility in an organic solvent such as toluene using an organic ligand such as trioctylphosphine (hereinafter abbreviated as TOPO) are reported. Further, the use of a thin film-shaped molded article containing such ultrafine particles is described in, for example, V.S. L. Colvin et al .;
Nature, vol. 370, p. 354 (1994) and JP-T-7-502479. However, conventional ultrafine semiconductor crystal particles contain organic ligands typified by trialkylphosphine oxides such as TOPO or trialkylphosphine (hereinafter abbreviated as TOP) such as polystyrene and polyalkylene. Solubility in general-purpose transparent organic polymer media such as methyl methacrylate is not always sufficient, and often gives a heterogeneous composition due to phase separation in the polymer matrix of ultrafine particles, and optics that require a high degree of transparency There were limitations on the application to the field.

On the other hand, it is known that a molecule having a hyperbranched structure represented by a dendrimer has excellent solvent solubility as compared with a linear molecule having a similar molecular weight. For example, V. Chechik et al .; Langmuir, 15,
On page 6364 (1999), Aldrich
Polyamideamine (PAMAM) dendrimer commercially available under the trademark "Starburst" (4th generation, theoretical molecular weight 1)
When part or all of the surface amino group (containing 4215 surface amino groups in one molecule) is converted to 3-mercaptopropanoic acid amide, the mercapto group coordinates on the surface of the colloidal gold particles, and this is converted to water-soluble. It has been reported that In this case, the dendrimer molecular chain has a spherical spatial spread, which is considered to be flexible and flattened to cover the surface of the gold colloid particles. Although an absorption band having a peak at 515 nanometers (hereinafter referred to as nm), which is considered to be due to the quantum effect of the colloidal gold particles, has been reported, such metal particles have a valence band (Valence band) found in semiconductors. In principle, it does not have emission characteristics based on electronic excitation to a conduction band, and it was not possible to coordinate the PAMAM dendrimer on the surface of semiconductor ultrafine particles by the technique described in this report.

[0005] K. Sooklal et al .; Adv. Mate
r. 10: 1083 (1998) describes the fourth-generation amino-terminal PAMAM or the 3.5-generation PA having the same number of terminal carboxyl groups.
A composite of a MAM dendrimer and cadmium sulfide (CdS) ultrafine particles has been reported, and it has been reported that this composite composition has a blue light emitting ability. However, this report does not discuss the use of elements such as sulfur and phosphorus that form stable coordination bonds with ultrafine CdS particles, and the dendrimer used has a spherical aliphatic amidoamine molecular chain. It was limited to those having a hydrophilic functional group such as an amino group or a carboxyl group attached to its terminal, so in terms of stability of such a complex or solubility in a general-purpose organic medium such as a solvent or a transparent resin. Practical problems remained.

[0006] Z. Bo et al .; Chem. Lett. , 11
P. 97 (1998) states that the focal point is a mercapto group (-SH) or a disulfide group (-SS).
It has been reported that a polybenzyl ether dendrimer having-) and bonding to a bulk gold surface via the sulfur functional group are reported. However, the dendrimer could not be coordinated to the surface of the ultrafine semiconductor crystal particles by the technique disclosed herein.

[0007] Another effect of dendrimers is the Site Exclusion effect due to the spatial expansion of their large hyperbranched skeleton. Kawa
Chem. Mater. Volume 10, 286-296
(1998), when such an effect is exerted on the surface of a semiconductor crystal, undesirable effects from the outside (for example, surface alteration by reactive molecules such as solvents, acids, bases, oxygen, and ozone) are caused. Although an effect of shielding is expected, the technique of the above-mentioned literature could not coordinate the dendrimer on the surface of the semiconductor crystal.

[0008]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its main object to provide an unprecedented excellent solubility of ultrafine semiconductor crystal in a medium and uniform film formation. In addition, the present invention is to provide a property of shielding the particles from unwanted influences from the outside and to provide a suitable production method and application of such ultrafine particles.

[0009]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that the focal point of a hyperbranched molecule such as a dendron has a coordination force to a transition metal such as sulfur or phosphorus. When an element having an introduced element is used as a ligand of a semiconductor crystal ultrafine particle, the ultrafine particle has extremely excellent solubility in a medium, a thin film forming property, and a shielding effect from undesired influence from the outside. It has been found that the present invention works, and the present invention has been achieved.

That is, the gist of the present invention is as follows. 1. Ultrafine semiconductor crystal particles in which a hyperbranched molecule is bonded as a ligand at its focal point; 2. A method for producing ultrafine semiconductor crystal particles, comprising a step of performing a ligand exchange reaction with a hyperbranched molecule. 3. The method for producing ultrafine semiconductor crystal particles as described above, wherein the hyperbranched molecule is introduced by a chemical reaction of a functional group present on the surface of the ultrafine semiconductor crystal particles. A thin film-shaped compact containing the semiconductor crystal ultrafine particles,
There are four points.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION [Hyperbranched Molecule] The hyperbranched molecule in the present invention is a molecule having a dendrimer structure or a dendritic hyperbranched structure similar thereto. For example, D.
A. Tomalia et al .; Angew. Chem. In
t. Ed. Engl. 29, pp. 138-175 (1
990) or Kakimoto; Chemistry, 50, 608-61
The so-called Hyper described on page 2 (1995)
Molecules referred to collectively as branched polymers correspond to this. As schematically shown in FIG. 1, the starting point of such a hyperbranch is called a focal point. Molecular weight
From the molecular weight distribution and variability of the terminal group and its controllability, a dendrimer structure which is a molecule having a completely regular hyperbranched structure is most suitable for the present invention. Note that, as schematically shown in FIG. 1, the degree of branching of the dendrimer structure is referred to as “generation”.

The hyperbranched molecule used in the present invention coordinates at the focal point to the semiconductor crystal body described later to form the ultrafine particles of the present invention. The commercially available PAMAM dendrimer used in the above-mentioned literature does not fall under the ultrafine particles of the present invention because it is bonded to the ultrafine particles by its surface functional group. Therefore, a typical structural concept of the hyperbranched molecule suitably used in the present invention is a structure generally called a dendron, that is, for example, G.I. R. Newcome
"Dendritic Molecules: Co
ncepts, Synthesis, Perspect
eves "; VCH Verlagsgesellsc
Haft mbH (Weinheim, Germany)
ny, 1996), page 110,
An example is a structure mainly used as a "part" of a dendrimer molecule obtained by a synthesis strategy assembled from constituent units on the hyperbranched terminal side called a Convergent method.

In general, when a structural formula is written on a sheet of paper, a dendron is represented by a form in which dendritic branches are sequentially spread in a fan shape (or wedge shape; also called a wedge). In addition, actually taking such a conformation has been reported by, for example, the study of polybenzyl ether dendron having an alcoholic hydroxyl group as a focal point functional group by a structural study of a monomolecular film (LB film) on the water surface. M. Sa
Ville et al .; J. Phys. Chem., 99, 8
283 (1995).

As schematically shown in FIG. 2, when the wedge-shaped conformation of the dendron has a metal coordinating element such as phosphorus or sulfur described below in its focal point functional group, the spherical shape of the semiconductor crystal ultrafine particles It is presumed that one of the factors of the excellent effect of the present invention is to efficiently coat.
Examples of the structure of the hyperbranched molecule that can be used in the present invention include those described in G. R. Various structures described in a new book by Newcome et al.
For example, E. Buhleier et al .; Synthesi
s, 1978, p. 155; M. M. de
Brabander-van den Berg et al .;
Angew. Chem. Int. Ed. Engl. , 3
2, 1308 (1993), C.I. J. Hawker et al .; A
m. Chem. Soc. 112, 7638 (19
90) the polybenzyl ether structure reported in
A. Morikawa et al .; Macromolecule
s, 26, 6324-6329 (1993);
M. Miller et al .; Am. Chem. Soc. ,
115, 356-357 (1993); J. H
awker et al .; Macromolecules, 29
Vol., 4370-4380 (1996); Mori
Kawa; Macromolecules, Vol. 31, 5
Various aromatic polyether ketone structures reported on pages 999 to 6009 (1998) and the like. J. Hawke
R et al. Am. Chem. Soc. , 113, 45
P. 83 (1991); Malmstrom et al .; Macromol
ecules, 28, 1698 (1995), the poly [2,2-bis (hydroxymethyl) propionic acid] structure; Morikawa et al .; Poly
mer J .; , 24, p. 573 (1992); Roovers et al .;
Polym. Preprints, vol. 33, p. 182 (1992), a polycarbosilane structure,
G. FIG. R. Newcome et al .; Org. Chem. ,
50, 2003 (1985), the same polyamidoamine structure as the above-mentioned PAMAM dendrimer commercially available from Aldrich, or M.I. Jayaraman et al .; Am.
Chem. Soc. 120, 12996 (199
8) aliphatic polyether structures reported in H .; I
Hre et al; Macromolecules, Vol. 31, 4
P.061 (1998), from the viewpoint of ease of synthesis and stability, the polypropylene imine structure, the polyamidoamine structure, the aliphatic polyether structure, the polybenzyl ether structure, The aromatic polyether ketone structure; The aliphatic polyester structure by Ihr et al. Is preferable, and the aliphatic polyether structure, the aromatic polyether ketone structure, the polybenzyl ether structure, or the H.I. The aliphatic polyester structure and the like according to Ihr et al. Are more preferable, and among them, those containing an aromatic group such as the polybenzyl ether structure or the aromatic polyether ketone structure in the repeating unit are more preferable, and 3,5-dioxybenzyl residue is preferable. Most preferred is a polybenzyl ether structure having a group as a repeating unit. When a dendron having a polybenzyl ether structure having a 3,5-dioxybenzyl group as a repeating unit or the aromatic polyether ketone structure is used as a ligand, the dendron becomes UV
Since light is absorbed, the sensitizing effect may enhance the emission of the ultrafine semiconductor crystal particles, which is very preferable.

Particularly preferred specific structures of polybenzyl ether dendron are the following general formula (1) of the first generation, the following general formula (2) of the second generation, and the following general formula (3) of the third generation: ). The general formula (1)
In (3), L represents a focal point functional group.

[0016]

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[0017]

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[0018]

Embedded imagePolybe having such a focal point functional group L
The benzyl ether dendron is described in, for example, Z. et al. Bo et al.
As described in the well-known literature, a suitable reagent providing a functional group L
In the above C. J. Hawker et al .; Am. Che
m. Soc. 112, 7638 (1990).
Known generation dendritic benzyl bromine
Can be synthesized by a nucleophilic substitution reaction acting on
You. Suitable reagents that provide such a functional group L include, for example,
If ammonia, phosphine (PH _Three) And arsine (A
sH_Three) And other hydrides of primary group 15 elements
Amines having active hydrogen such as amines and secondary amines, azide
Sodium azide, hydrogen sulfide and hydrogen selenide
Or hydrogenation of Group 16 elements of the periodic table, such as hydrogen telluride
Material, sodium sulfide or sodium selenide
Alkali metal salts of Group 16 elements, thiourea, thioa
Sulfating agents such as cetamide and ammonium thiocyanate
Is mentioned. Such a nucleophilic substitution reaction is, for example, N, N-
Amines such as dimethylformamide and N-methylpyrrolidone
Ethers such as tetrahydrofuran
A suitable base (eg, sodium hydride,
Metal hydrides such as calcium hydride, sodium hydroxide
Alkalis such as sodium hydroxide and potassium hydroxide, sodium carbonate
Metal carbonates such as potassium and potassium carbonate, triethyl alcohol
3 such as min, ethyldiisopropylamine, 9-BBN
Amines, pyridine and 4-dimethylaminopyridine (D
MAP) and other nitrogen-containing aromatic compounds).
It is. In this case, if necessary, increase the temperature to about 30 to 150 ° C.
You can heat it. Also, products or reaction intermediates
If easily decomposed by light irradiation or oxidation, block light
Conditions or under an atmosphere of inert gas such as nitrogen or argon
In some cases, it is preferable to carry out the reaction.

Since the hyperbranched molecule used in the present invention is not limited in its branched structure as long as it is a hyperbranched molecule, it does not have to be a completely controlled dendron. No restrictions. When dendrons are used, the number of generations is usually 1 to 5, preferably 1 to 4, more preferably 1 to 3, and most preferably 2 to 3 in view of solubility and ease of synthesis.

The weight average molecular weight of the hyperbranched molecule preferably used in the present invention is from 250 to 30,000, preferably from 300 to 20,000, more preferably from 300 to 10,000, even more preferably from 300 to 8,000. 0
00, most preferably 300-6,000. If the molecular weight is too small, the effect of imparting solubility to the ultrafine semiconductor crystal particles, which is the object of the present invention, may be insufficient, while if too large, the coordination ability may be extremely reduced.

The molecular weight distribution of the hyperbranched molecule is ideally 1 (ie, there is no distribution in the molecular weight such as an ideal dendron, etc.) as the value of the ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn. State), but it is usually preferably 1 to 10, more preferably 1 to 7, further preferably 1 to 5, and most preferably 1 to 3. The molecular weight and molecular weight distribution of the hyperbranched molecule can be determined, for example, by mass spectrometry, in particular, by MALDI-TOF-MS (Matr
ix-assisted laser desorpt
ion ionization time-of-fl
It is preferably measured by a light mass spectrum.

Since the non-focal point end of the hyperbranched molecule (ie, the hyperbranched end) comes to the outermost shell when functioning as a ligand, its terminal group structure affects the solubility of the whole ultrafine particles. Is an important factor to give. Preferred terminal group structures include a phenyl group, a 4-methylphenyl group, a 4-ethylphenyl group, a 4-isopropylphenyl group, and a 4-tert-butylphenyl group as shown in the general formulas (1) to (3). Alkyl-substituted phenyl groups, phenyl groups having a carbon-carbon multiple bond as a substituent, such as 4-vinylphenyl group, 3-vinylphenyl group and 4-ethynylphenyl group, 4-methoxyphenyl group and 4-ethoxyphenyl Group, 3-methoxyphenyl group, 3,5-dimethoxyphenyl group, alkoxy-substituted phenyl groups such as phenyl group in which triethylene glycol monomethyl ether residue is bonded to the 4-position, 4-chlorophenyl group, 3-chlorophenyl group, Halogen-substituted phenyl groups such as 4-bromophenyl group and 4-iodophenyl group, 4-acetoxy And acyl-substituted phenyl groups such as phenyl, 3-acetoxyphenyl, 3,5-diacetoxyphenyl, 4-acryloyloxyphenyl, 3-acryloyloxyphenyl, and 4-methacryloyloxyphenyl. You. Among these, alkyl-substituted phenyl groups such as phenyl group, 4-methylphenyl group, 4-isopropylphenyl group and 4-tert-butylphenyl group, 4-methoxyphenyl group, Alkoxy-substituted phenyl groups such as methoxyphenyl group and 3,5-dimethoxyphenyl group, 4-acetoxyphenyl group, 3-acetoxyphenyl group, 3,5-
Acyl-substituted phenyl groups such as diacetoxyphenyl group; and alkyl-substituted phenyl groups such as phenyl group and 4-methylphenyl group, 4-methoxyphenyl group, 3-methoxyphenyl group, and 3,5-dimethoxy. More preferred are alkoxy-substituted phenyl groups such as phenyl groups. A 4-vinylphenyl group, a 3-vinylphenyl group, a 4-ethynylphenyl group, a 4-acryloyloxyphenyl group, a 3-acryloyloxyphenyl group,
-Phenyl groups having a carbon-carbon multiple bond such as a methacryloyloxyphenyl group in a substituent impart polymerization reactivity such as a radical reaction or an ionic reaction to the surface of the ultrafine particles. After dissolving in a general-purpose transparent resin monomer of the above, it is suitable as a terminal group for obtaining a resin composition by radical copolymerization in the presence of a radical initiator such as azobisisobutyronitrile, and particularly a 4-vinylphenyl group is Ideal for this purpose.

In the present invention, a plurality of different types of hyperbranched molecules may be mixed and used as a coordination. [Focal Point Functional Group] In the hyperbranched molecule used in the present invention, the focal point functional group is the first in the periodic table.
It is desirable to contain a Group 5 or 16 element. This is because the group 15 or 16 element of the periodic table has a strong coordination force with respect to the metal element, so that it is easy to realize the coordination to the semiconductor crystal ultrafine particles at the focal point as schematically shown in FIG. is there.

The term "focal point functional group" as used herein means a focal point structure of a hyperbranched molecule (for example, a benzene ring located at the focal point in the above general formulas (1) to (3) corresponds to a PAMAM dendrimer). (It may be a single atom such as a nitrogen atom in a structure or a polypropyleneimine structure.) The terminal functional group is bonded via 0 to 5 linking groups as the number of atoms bonded linearly. Preferred as such a linking group are a methylene chain having 5 or less carbon atoms, an oxygen atom (ether bond), a sulfur atom (thioether bond or sulfide bond), a disulfide bond, an ester bond, a carbonate bond, an amide bond, a urea bond, and a urethane bond. And so on.
The focal point functional group may be directly bonded to the above-mentioned focal point structure without such a linking group, or the focal point structure itself contains the focal point functional group or is the same as the focal point functional group itself. It does not matter. For example, a tertiary amino group, a phosphine group, a phosphine oxide group, or the like can itself have a three-branch focal point structure.

Preferred focal point functional groups containing Group 15 or 16 elements of the Periodic Table include a primary amino group (—NH ₂ ) and a secondary amino group (—NHR; where R is a methyl group, an ethyl group, a propyl group). A hydrocarbon group having 6 or less carbon atoms, such as a butyl group, a butyl group or a phenyl group;
A ^primary amino group (—NR ¹ R ² ; provided that R ¹ and R ² are independently a hydrocarbon group having 6 or less carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a phenyl group, and the like); Nitrogen-containing functional groups such as pyridyl groups, primary phosphine groups (-PH
₂ ) Secondary phosphine group (-PHR), tertiary phosphine group (-PR ¹ R ² ), primary phosphine oxide group (-PH
₂ = 0) secondary phosphine oxide group (-PHR =
O) a tertiary phosphine oxide group (—PR ¹ R ² ＯO),
Primary phosphine selenide group (-PH ₂ = Se), ₂ phosphine selenide group (-PHR = Se), such as phosphorus-containing functional group such as a tertiary phosphine selenides group (-PR ¹ R ² = Se) A functional group containing a Group 15 element of the periodic table, a hydroxyl group (-
OH), a methyl ether group (—OCH ₃ ), a phenyl ether group (—OC ₆ H ₅ ), a carboxyl group (—COO
H) the oxygen-containing functional group such as a mercapto group (or thiol group; -SH), methyl sulfide group (-SCH _3), ethyl sulfide group (-SCH ₂ CH _3), phenyl sulfide group (-SC ₆ H ₅₎ , A methyl disulfide group (-S-
S-CH _3), phenyl disulfide group (-S-S-C ₆
H ₅ ), thioic acid group (—COSH), dithioic acid group (—CS
SH), xanthate, xanthate group, isothiocyanate group, thiocarbamate group, a thiophene sulfur-containing functional group ring and, similarly -SeH, -SeCH _3, -S
Functional groups containing elements of Group 16 of the periodic table, such as selenium-containing functional groups such as eC ₆ H ₅ and —Se—Se—CH ₃ are exemplified. Of these, preferred are Group 15 elements of the periodic table such as nitrogen-containing functional groups such as pyridyl groups, tertiary phosphine groups, tertiary phosphine oxide groups, and phosphorus-containing functional groups such as tertiary phosphine selenide groups. And a functional group containing a Group 16 element of the periodic table such as a sulfur-containing functional group such as a mercapto group and a methylsulfide group.
Phosphorus-containing functional groups such as tertiary phosphine groups and tertiary phosphine oxide groups, and sulfur-containing functional groups such as mercapto groups are more preferably used, and mercapto groups are most preferably used.

A particularly preferred specific structure of the dendron having a focal point functional group is L in formulas (1) to (3) having a polybenzyl ether structure.
Is a mercapto group (—SH), or a dendron having a polybenzyl ether structure having a phosphine group as a focal point structure described in the following formulas (4) and (5); )
And a dendron having a polybenzyl ether structure having a phosphine oxide group as a focal point structure.

[0027]

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[0028]

Embedded image

[0029]

Embedded image

[0030]

Embedded image Such a dendron having a phosphine group or a phosphine oxide group as a focal point structure (hereinafter abbreviated as phosphine dendron or phosphine oxide dendron, respectively) is, for example, tris (3-hydroxypropyl) phosphine or a corresponding phosphine oxide, tris (3 -Hydroxypropyl) phosphine oxide and the above-mentioned dendritic benzyl bromide are ether-bonded by condensation in the presence of a suitable base.

In particular, when phosphine dendrons are obtained, the phosphine group is easily oxidized in the presence of molecular oxygen. Therefore, the reaction is preferably carried out in an atmosphere of an inert gas such as nitrogen or argon. In some cases, it is preferable to perform the replacement and degassing by bubbling with such an inert gas. When the product or the reaction intermediate is easily decomposed by light irradiation or oxidation, it may be preferable to carry out the reaction under light-shielding conditions.

The hyperbranched molecule having a focal point functional group which is easily oxidized, such as a mercapto group or a phosphine group, may be refrigerated or frozen as required under an inert atmosphere such as nitrogen or argon and / or under light-shielding conditions. May be desirable. It is to be noted that the bonding mode in which such a focal point functional group is actually bonded to the semiconductor crystal ultrafine particles has not been completely elucidated, but the fifteenth table of the periodic table such as phosphorus or sulfur has not been completely elucidated.
Alternatively, it is presumed that the group 16 element has an ionic bond, a covalent bond, or a coordinate bond with a metal element in a semiconductor crystal composition described later.

[Ultrafine Particles] The ultrafine semiconductor crystal particles of the present invention contain a semiconductor crystal as an essential component as exemplified below, and are exciton quasi-quantized by a quantum effect controlled by the semiconductor crystal particle diameter. It is desirable to show the phenomenon of absorption and / or generation of electromagnetic waves in which the position is involved. The wavelength range of absorption and / or generation of electromagnetic waves that is particularly useful for application is light in the far ultraviolet to infrared region, and is usually 150 to 1.
0000 nm, preferably 180-8000 nm, more preferably 200-6000 nm, most preferably 22
The range is about 0 to 4000 nm.

The ultrafine semiconductor crystal particles of the present invention have a semiconductor crystal body and a hyperbranched molecule coordinated on the surface thereof as essential components. The semiconductor crystal body may be any of a semiconductor single crystal, a mixed crystal in which a plurality of semiconductor crystal compositions are phase-separated, and a mixed semiconductor crystal in which phase separation is not observed, and may have a core-shell structure described later. The particle size of the semiconductor crystal body is usually 1 to 20 nm as a number average particle size, and preferably 2 to 1 in terms of electromagnetic characteristics such as light absorption and light emission.
It is about 2 nm, more preferably about 2.5 to 10 nm.
Such a particle size can usually be determined by observation with a transmission electron microscope (TEM). However, when the atomic number of the contained element is small and it is difficult to obtain a contrast with an electron beam, observation with an atomic force microscope (AFM) or It can be estimated by combining the results of composition analysis such as elemental analysis with the light scattering or neutron scattering measurement in a solution.

The particle size distribution of the semiconductor crystal body is not limited as long as it is within the range of the above average particle size.
If the light absorption and light emission characteristics of the semiconductor crystal body due to the quantum effect are used, there is a case where the required light emission wavelength width can be changed by changing the distribution. When the wavelength width needs to be narrowed, the particle size distribution is narrowed, but the standard deviation is usually within ± 30%, preferably within ± 20%, and more preferably within ± 10%. In the case of a particle size distribution exceeding the standard deviation range, it is difficult to sufficiently achieve the purpose of narrowing the emission wavelength width due to the quantum effect.

[Semiconductor crystal] Semiconductor crystal in the present invention
There is no particular limitation on the semiconductor crystal composition contained in the ultrafine particles
Preferably contains an element belonging to Groups 12 to 17 of the periodic table.
Good. A set of semiconductor crystals usable for the ultrafine particles of the present invention
If the example is illustrated as an element symbol or a composition formula, C,
P, elemental element of group 14 of the periodic table such as Si, Ge, Sn
Simple substance of Group 15 element such as (black phosphorus), Se or Te
Of Periodic Table Group 16 elements, multiple periods of SiC, etc.
Compounds composed of elements of Table 14 Group, SnO_Two, Sn (II)
Sn (IV) S_Three, SnS_Two, SnS, SnSe, SnT
e, PbS, PbSe, PbTe, etc., periodic table group 14 elements
Of element and element of group 16 of the periodic table, BN, BP, BA
s, AlN, AlP, AlAs, AlSb, GaN, G
aP, GaAs, GaSb, InN, InP, InA
Group 13 elements of the periodic table such as s and InSb and Group 15 of the periodic table
Compounds with elements (or III-V compound semiconductors),
Al_TwoS_Three, Al_TwoSe_Three, Ga_TwoS_Three, Ga_TwoSe_Three, Ga_Two
Te_Three, In_TwoO_Three, In_TwoS_Three, In_TwoSe_Three, In_TwoTe_Three
Of group 13 elements of the periodic table with elements of group 16 of the periodic table
, TlCl, TlBr, TlI, etc.
Compound of element and element of group 17 of the periodic table, ZnO, ZnS,
ZnSe, ZnTe, CdO, CdS, CdSe, Cd
Group 12 of the periodic table such as Te, HgS, HgSe, HgTe
Compound of element and element of group 16 of the periodic table (or II-VI
Group compound semiconductor), As_TwoS_Three, As_TwoSe_Three, As_TwoT
e_Three, Sb_TwoS_Three, Sb_TwoSe_Three, Sb_TwoTe_Three, Bi_TwoS_Three,
Bi_TwoSe_Three, Bi_TwoTe_ThreeGroup 15 elements and period of the periodic table
Table 16 Compounds with Group 16 Elements, Cu_TwoO, Cu_TwoCircumference of Se etc.
A compound of a Group 11 element of the Periodic Table and a Group 16 element of the Periodic Table, C
circumference of uCl, CuBr, CuI, AgCl, AgBr, etc.
A compound of an element of Group 11 of the Periodic Table and an element of Group 17 of the Periodic Table, N
of group 10 elements of the periodic table such as iO and group 16 elements of the periodic table
Group 9 elements of the periodic table such as compounds, CoO, and CoS and the periodic table
Compounds with Group 16 elements, Fe_ThreeO_FourSuch as iron oxides, Fe
Compounds of group 8 elements of the periodic table such as S with elements of group 16 of the periodic table
, Group 16 elements of the periodic table, such as substances and MnO
With MoS_Two, WO_TwoPeriodic Table 6 elements such as
Compounds with Group 16 elements, VO, VO_Two, Ta_TwoO_Five
Of group 5 elements of the periodic table with elements of group 16 of the periodic table
Object, TiO_Two, Ti_TwoO_Five, Ti_TwoO _Three, Ti_FiveO₉Oxidation of etc.
Titanium (crystal type is rutile type, mixed rutile / anatase
Crystalline or anatase type), ZrO_Two
Of group 4 elements of the periodic table with elements of group 16 of the periodic table
, MgS, MgSe and other elements of the Periodic Table
Compound with group 16 element, CdCr_TwoO_Four, CdCr_TwoS
e_Four, CuCr_TwoS_Four, HgCr_TwoSe_FourEtc. chalcogens
Pinels or BaTiO_ThreeAnd the like. What
Contact, G. Schmid et al .; Adv. Mater. , 4
Volume, page 494 (1991) (BN)₇₅
(BF_Two)_FifteenF_FifteenAnd D. Fenske et al .; Ang
w. Chem. Int. Ed. Engl. , 29 volumes, 1
Cu reported on page 452 (1990)₁₄₆Se₇₃
(Triethylphosphine)_{twenty two}Like the structure is determined
Semiconductor clusters are also exemplified.

Among these, those which are practically important are, for example, SnO ₂ , SnS ₂ , SnS, SnSe, SnTe, P
Compounds of Group 14 elements and Group 16 elements such as bS, PbSe, PbTe, etc., GaN, GaP, GaAs
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, In ₂ Te periodic table Group 13 element ₃ or the like and the Periodic Table 1
Compounds with Group 6 elements, ZnO, ZnS, ZnSe, Zn
Te, CdO, CdS, CdSe, CdTe, HgO,
HgS, HgSe, II-VI group compound such as HgTe _{semiconductor, As 2 O 3, As 2} S 3, As 2 Se 3, As 2 Te 3, 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 periodic table Group 15 element and the periodic table compounds of Group 16 elements such as _3, the periodic table, such as titanium oxides and ZrO ₂ of the It is a compound of an element of Group 4 and an element of Group 16 of the periodic table, and a compound of an element of Group 2 of the periodic table such as MgS and MgSe and an element of Group 16 of the periodic table.

Among these, SnO_Two, GaN, Ga
P, In_TwoO_Three, InN, InP, Ga_TwoO_Three, Ga_TwoS_Three,
In_TwoO_Three, In_TwoS_Three, ZnO, ZnS, CdO, Cd
S, the above-mentioned titanium oxides and ZrO_Two, MgS, etc. have high bending
It has a high refractive index and does not contain highly toxic negative elements.
It is preferable in terms of environmental pollution and safety to living organisms.
Then SnO_Two, In_TwoO_Three, ZnO, ZnS, oxidation as described above
Titanium and ZrO_TwoDoes not contain highly toxic positive elements such as
The composition is more preferable, among which ZnO or the above-mentioned acid
Titanium iodides (rutile crystals are particularly preferred for high refractive index
Preferred) and ZrO _TwoOxide semiconductor crystals such as
New The rutile titanium oxide crystal particles have a longer wavelength absorption.
The end is usually around 400 nm in the bulk state.
The number average particle size of the crystal particles is 0.5 to 3 which is within the range of the present invention.
By setting the wavelength to about 0 nm, the absorption wavelength at the longer wavelength side becomes shorter.
Wavelength, making it possible to reduce colorlessness in the visible region.
There may be advantages to improve.

GaN, GaP, GaAs, InN, InP having an emission band near and in the practically important visible region
III-V compound semiconductors such as ZnO, ZnS, ZnS
e, ZnTe, CdO, CdS, CdSe, CdTe,
II-VI compound semiconductors such as HgO and HgS, In ₂
O ₃ , In ₂ S _{3 and the} like are important, and among them, ZnO, ZnS, Z
II such as nSe, ZnTe, CdO, CdS, CdSe
-VI group compound semiconductors, particularly ZnSe, CdS,
CdSe and the like are more preferably used for this purpose.

The composition of any of the semiconductor crystals exemplified above may include, for example, Al, Mn, Cu, Zn, A as a small amount of a doping substance (meaning the intentionally added impurity) as necessary.
Elements such as g, Cl, Ce, Eu, Tb, and Er may be added. [Semiconductor Crystal Particles Having Core-Shell Structure] The semiconductor crystal particles are, for example, A.I. R. Kortan et al .; A
m. Chem. Soc. 112, 1327 (19
90) or US Pat. No. 5,985,173 (199).
As reported in 9), the inner core and outer shell are used to improve the electronic excitation characteristics of the semiconductor crystal.
When a so-called core-shell structure is used, the stability of the quantum effect of the semiconductor crystal forming the core may be improved in some cases. Therefore, applications utilizing an absorption band or an emission band based on exciton levels, such as a spherical fine particle optical resonator May be suitable. In this case, it is generally effective to form an energy barrier by using a semiconductor crystal having a band gap larger than that of the core as a composition of the semiconductor crystal of the shell. This is presumed to be due to a mechanism for suppressing the influence of an undesirable surface level or the like due to the influence of the outside world or a crystal lattice defect on the crystal surface.

The composition of the semiconductor crystal preferably used for such a shell depends on the band gap of the core semiconductor crystal.
At least 2.0 eV, for example, B
N, BAs, III-V compound semiconductors such as GaN and GaP, ZnO, ZnS, ZnSe, ZnTe, CdO, C
II-VI group compound semiconductors such as dS, and compounds of Group 2 element and Group 16 element such as MgS and MgSe are preferably used. Among these, the semiconductor crystal composition that is a more preferable shell is III, such as BN, BAs, and GaN.
-V group compound semiconductor, ZnO, ZnS, ZnSe, Cd
1. The bandgap of a bulk state of a compound of a II-VI compound semiconductor such as S, a compound of a Group 2 element of the Periodic Table and a Group 16 element of the Periodic Table such as MgS and MgSe, etc. at 300K.
3 eV or more, most preferably B
N, BAs, GaN, ZnO, ZnS, ZnSe, Mg
The band gap of bulk state of S, MgSe, etc. is 3
At 00K, it is 2.5 eV or more, and ZnS is most preferably used in chemical synthesis.

A particularly preferable example of the combination of the core-shell composition used in the semiconductor crystal body of the present invention is represented by a composition formula: CdSe-ZnS, CdSe-ZnO, CdS
e-CdS, CdS-ZnS, CdS-ZnO and the like can be mentioned. [Auxiliary ligand] The ultrafine semiconductor crystal particles of the present invention have an auxiliary ligand other than the above-mentioned hyperbranched molecule on the surface thereof for the purpose of suppressing and stabilizing undesired effects such as aggregation. It does not matter. Such ligands are exemplified below. (A) Sulfur-containing compound: mercaptoethane, 1-mercapto-n-propane, 1-mercapto-n-butane, 1-mercapto-n-hexane, mercaptocyclohexane, 1-mercapto-n-octane, 1-mercapto Mercaptoalkanes such as -n-decane; thiophenol derivatives such as thiophenol, 4-methylthiophenol and 4-tert-butylthiophenol; dimethyl sulfide, diethyl sulfide, dibutyl sulfide, dihexyl sulfide, dioctyl sulfide, didecyl sulfide and the like Dialkyl sulfoxides, dimethyl sulfoxide, diethyl sulfoxide, dibutyl sulfoxide, dihexyl sulfoxide, dioctyl sulfoxide, dialkyl sulfoxides such as didecyl sulfoxide, and dimethyl disulfide. Rufido, diethyl disulfide, dibutyl disulfide, dihexyl disulfide,
Dialkyl disulfides such as dioctyl disulfide and didecyl disulfide; compounds having a thiocarbonyl group such as thiourea and thioacetamide; sulfur-containing aromatic compounds such as thiophene; and one end represented by the following general formula (8) became a mercapto group. Polyethylene glycols and the like.

[0043]

R- (OCH ₂ CH ₂ ) n-SH (8) In the general formula (1), R represents a hydrogen atom or a carbon atom
0 or less hydrocarbon group (for example, methyl group, ethyl group, n-
A propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a hexyl group, an octyl group, a nonyl group, a phenyl group or the like, and preferably a methyl group or an ethyl group), and n is a natural number representing the degree of polymerization. Yes, usually 2 ≦ n
≦ 50, preferably 2 ≦ n ≦ 40, more preferably 2 ≦ n ≦ 30, most preferably 2 ≦ n ≦ 20 from the viewpoint of avoiding excessive steric hindrance. (B) Phosphorus-containing compound: trialkylphosphines such as triethylphosphine, tributylphosphine, trihexylphosphine, trioctylphosphine, tridecylphosphine, triethylphosphine oxide, tributylphosphine oxide, trihexylphosphine oxide, trioctylphosphine oxide , Trialkylphosphine oxides such as tridecylphosphine oxide; aromatic phosphines such as triphenylphosphine and triphenylphosphine oxide; and aromatic phosphine oxides. (C) Nitrogen-containing compounds: nitrogen-containing aromatic compounds such as pyridine and quinoline, trimethylamine, triethylamine, tributylamine, trihexylamine, trioctylamine, tridecylamine, triphenylamine, methyldiphenylamine, diethylphenylamine, Tertiary amines such as tribenzylamine, diethylamine, dibutylamine, dihexylamine, dioctylamine, didecylamine, diphenylamine, secondary amines such as dibenzylamine, hexylamine, octylamine, decylamine, dodecylamine, hexadecylamine, Primary amines such as octadecylamine, phenylamine and benzylamine; carboxylic acid esters having an amino group such as triethyl nitrilotriacetic acid ester;

Of these exemplified auxiliary ligands, preferred are mercaptoethane, 1-mercapto-n-propane, 1-mercapto-n-butane, 1-mercapto-
6 carbon atoms such as n-hexane and mercaptocyclohexane
The following mercaptoalkanes, thiophenol, 4-methylthiophenol, thiophenol derivatives such as 4-tert-butylthiophenol, dimethyl sulfide,
Dialkyl sulfides having a total carbon number of 8 or less such as diethyl sulfide and dibutyl sulfide; sulfur-containing compounds such as dialkyl sulfoxides having a total carbon number of 8 or less such as dimethyl sulfoxide, diethyl sulfoxide and dibutyl sulfoxide; tributyl phosphine, trihexyl phosphine; Trialkylphosphines having a total carbon number of 24 or less such as octylphosphine, triethylphosphine oxide, tributylphosphine oxide, trihexylphosphine oxide, trialkylphosphine oxides having a total carbon number of 24 or less such as trioctylphosphine oxide, triphenylphosphine and the like. Aromatic phosphines such as triphenylphosphine oxide or phosphorus-containing compounds such as aromatic phosphine oxides, and nitrogen-containing aromatic compounds such as pyridine , And the inter alia mercapto ethane,
Total of mercaptoalkanes having 4 or less carbon atoms such as 1-mercapto-n-butane, thiophenol derivatives such as thiophenol, 4-methylthiophenol and 4-tert-butylthiophenol, dimethyl sulfide, diethyl sulfide and dibutyl sulfide Sulfur-containing compounds such as dialkyl sulfoxides having a total of 8 or less carbon atoms such as dialkyl sulfides having 8 or less carbon atoms, dimethyl sulfoxide, diethyl sulfoxide, and dibutyl sulfoxide; and trialkyls having a total carbon number of 18 or less such as tributyl phosphine and trihexyl phosphine. Phosphines, triethylphosphine oxide, tributylphosphine oxide,
Trialkyl phosphine oxides having a total carbon number of 18 or less such as trihexyl phosphine oxide, aromatic phosphines such as triphenyl phosphine and triphenyl phosphine oxide, and phosphorus-containing compounds such as aromatic phosphine oxides are more preferable.

[Method for Producing Ultrafine Semiconductor Crystal Particles] Any method such as the following conventional method for producing ultrafine semiconductor crystal particles may be used. Although the above-mentioned vacuum production process may be used, the following three liquid phase methods are exemplified as preferred methods. (A) A method in which a raw material aqueous solution is present as reverse micelles in a nonpolar organic solvent and crystals are grown in the reverse micelle phase (hereinafter referred to as “reverse micelle method”). S. Zou
Int. J. Quant. Chem. , 72, 4
39 (1999). A well-known reverse micelle stabilization technique can be used in a general-purpose reactor, relatively inexpensive and chemically stable salts can be used as raw materials, and the reaction is performed at a relatively low temperature that does not exceed the boiling point of water. It is a suitable method for production. However, the current technology may be inferior in light emission characteristics as compared with the hot soap method described below. (B) A method of injecting a thermally decomposable raw material into a high-temperature liquid-phase organic medium to grow crystals (hereinafter referred to as a hot soap method), for example, a method reported in the above-mentioned literature by Katari et al. . Semiconductor crystal particles having excellent particle size distribution and purity are obtained as compared with the above reverse micelle method, and the product is characterized by having excellent luminescence characteristics and being generally soluble in an organic solvent. For the purpose of desirably controlling the reaction rate during the crystal growth process in the liquid phase in the hot soap method, a coordinating organic compound having an appropriate coordinating power for a semiconductor constituent element is used as a liquid phase component (also serves as a solvent and a ligand). ). Examples of such coordinating organic compounds include the above trialkylphosphines, the above trialkylphosphine oxides, dodecylamine,
Ω-aminoalkanes such as tetradecylamine, hexadecylamine, and octadecylamine; and the above-mentioned dialkyl sulfoxides. Of these, trialkyl phosphine oxides such as TOPO and ω-aminoalkanes such as hexadecylamine are preferable. (C) A solution reaction involving semiconductor crystal growth similar to the above-mentioned hot soap method, but a method in which an acid-base reaction is performed at a relatively low temperature as a driving force has been known for a long time (for example, PA Jackson). J. Cryst. Growth
h, 3-4, 395 (1968)). Such a method is sometimes referred to as a sol-gel method.

The semiconductor raw materials usable in the three liquid phase production methods include a substance containing a positive element selected from Groups 2 to 15 of the periodic table and a negative element selected from Groups 15 to 17 of the periodic table. And the like. For example, in the above-mentioned hot soap method, an organic metal such as dimethylcadmium or diethylzinc, a tertiary phosphine such as trioctylphosphine or tributylphosphine dissolved in a tertiary phosphine or a chalcogenide element such as bis (trimethylsilyl) sulfide are used. A method of reacting the compound with TOPO is preferably used. Further, when, for example, zinc oxide is produced by the solution reaction of the above (c), L. Spa
nhel et al .; Am. Chem. Soc. , 113
Vol., P. 2826 (1991), wherein zinc acetate and lithium hydroxide are reacted in ethanol. When there are a plurality of semiconductor raw materials, these may be mixed in advance, or each of them may be independently injected into the reaction liquid phase. These raw materials may be used as a solution using an appropriate diluting solvent.

Examples of the compound containing a positive element serving as a semiconductor raw material compound include dialkylated compounds of Group 2 elements of the periodic table such as diethyl magnesium and di-n-butyl magnesium, methyl magnesium chloride, methyl magnesium bromide, and methyl iodide. Alkyl halides of Group 2 elements of the Periodic Table, such as magnesium and ethynyl magnesium chloride; dihalides of Group 2 elements of the Periodic Table, such as magnesium iodide; titanium tetrachloride (IV); titanium tetrabromide (IV); Halides of Group 4 elements of the periodic table, such as titanium (IV) halide;
Vanadium dichloride (II), vanadium tetrachloride (IV), vanadium dibromide (II), vanadium tetrabromide (IV), vanadium diiodide (II), vanadium tetraiodide (IV), tantalum pentachloride ( V), tantalum pentabromide (V), tantalum pentaiodide (V) and the like, halides of elements of Group 5 of the periodic table;
Chromium (III) tribromide, Chromium (III) triiodide, Molybdenum tetrachloride (IV), Molybdenum tetrabromide (IV), Molybdenum tetraiodide (IV), Tungsten tetrachloride (IV), Tungsten tetrabromide (IV) and other halides of Group 6 elements of the Periodic Table, such as manganese dichloride (II), manganese (II) dibromide, and manganese (II) diiodide. Iron (II) chloride, iron (III) trichloride, iron dibromide (I
I), iron (III) tribromide, iron (II) diiodide, iron (III) triiodide, halides of Group VIII elements, cobalt (II) chloride, cobalt (II) II), Periodic Table 10 such as Cobalt (II) and other halides of Group 9 elements, nickel dichloride (II), nickel dibromide (II) and nickel diiodide (II) Halides of group elements,
Halides of Group 11 elements of the Periodic Table, such as copper (I) iodide, dimethyl zinc, diethyl zinc, di-n-propyl zinc, diisopropyl zinc, di-n-butyl zinc, diisobutyl zinc, di-n-hexyl zinc , Dicyclohexyl zinc, dimethyl cadmium, diethyl cadmium, dimethyl mercury (II), diethyl mercury (II), dibenzyl mercury (II), etc., dialkylates of Group 12 elements, methyl zinc chloride, methyl zinc bromide, iodide Alkyl halides of Group 12 elements such as methyl zinc, ethyl zinc iodide, methyl cadmium chloride, methyl mercury (II) chloride, zinc dichloride, zinc dibromide, zinc diiodide, cadmium dichloride, Cadmium bromide, cadmium diiodide, mercury dichloride (II), zinc chloroiodide, cadmium chloroiodide, mercury chloroiodide (II) Bromide zinc iodide, 12 of the periodic table, such as bromide, iodide, cadmium bromide mercury iodide (II)
Group element dihalides, trimethylboron, tri-n
-Propyl boron, triisopropyl boron, trimethyl aluminum, triethyl aluminum, tri-n-
Butyl aluminum, tri-n-hexyl aluminum, trioctyl aluminum, tri-n-butyl gallium (III), trimethyl indium (III), triethyl indium (III), tri-n-butyl indium (I
II) trialkylated compounds of Group 13 elements such as dimethylaluminum chloride, diethylaluminum chloride, di-n-butylaluminum chloride, diethylaluminum bromide, diethylaluminum iodide, di-n-butylgallium chloride (III) ), Di-n-butylindium chloride (I
II) Dialkyl monohalides of Group 13 elements such as methylaluminum dichloride, ethylaluminum dichloride, ethylaluminum dibromide, ethylaluminum diiodide, n-butylaluminum dichloride, n-dichloride
Monoalkyl dihalides of Group 13 elements of the periodic table, such as -butyl gallium (III) and n-butyl indium (III) dichloride, boron trichloride, boron tribromide, boron triiodide, aluminum trichloride, triodor Aluminum iodide, aluminum triiodide, gallium (III) trichloride, gallium (III) tribromide, gallium (III) triiodide, indium (III) trichloride, indium (III) tribromide, indium triiodide (III), gallium dibromide (III), gallium dichloride (III), gallium diiodide (II)
I), periodic table 13 of indium (III) dichloride, etc.
Group trihalide, germanium tetrachloride (I
V), germanium tetrabromide (IV), germanium tetraiodide (IV), tin (II) dichloride, tin tetrachloride (IV), tin (II) dibromide, tin (IV) tetrabromide, Tin (II) iodide, tin (IV) tetrabromide, tin (IV) dichloride, tin (IV) tetraiodide,
Halides of Group 14 elements such as lead (II) dichloride, lead (II) dibromide, lead (II) diiodide, trimethylantimony (III), triethylantimony (III), tri-
n-butylantimony (III), trimethylbismuth (I
II), trialkylated compounds of Group 15 elements such as triethyl bismuth (III), tri-n-butyl bismuth (III), methyl antimony dichloride (III), methyl antimony dibromide (III), diiodide Methylantimony chloride (II
Monoalkyl dihalides of Group 15 elements of the Periodic Table, such as I), ethyl antimony (III) diethyl iodide, methyl bismuth (III) dichloride, ethyl bismuth (III) diiodide, arsenic trichloride (III), Arsenic (III) bromide, arsenic triiodide (III), antimony trichloride (III), antimony tribromide (III), antimony triiodide (III), bismuth trichloride (III), bismuth tribromide ( III), and trihalides of Group 15 elements of the periodic table such as bismuth (III) triiodide.

Incidentally, germanium tetrachloride (IV), germanium tetrabromide (IV), germanium tetraiodide (IV), tin dichloride (II), tin tetrachloride (IV), tin dibromide (II), Tin (IV) tetrabromide, Tin (II) diiodide, Tin (IV) tetrabromide, Tin (II) dichloride (IV), Tin (IV) tetraiodide, Lead (I) chloride
Halides of Group 14 elements of the periodic table, such as I), lead (II) dibromide, and lead (II) diiodide, are ultrafine particles of a single semiconductor of the Group 14 elements of the periodic table, such as germanium and tin. May be used as a raw material.

Examples of the compound containing a negative element which is a semiconductor raw material compound include nitrogen, phosphorus, arsenic, antimony, bismuth, oxygen, sulfur, selenium, tellurium, fluorine, chlorine, bromine, iodine and the like. Elemental group element, ammonia, phosphine (PH ₃ ), arsine (AsH ₃ ),
A hydride of a Group 15 element of the periodic table such as stibine (SbH ₃ ), a silylated product of a Group 15 element of the periodic table such as tris (trimethylsilyl) amine, tris (trimethylsilyl) phosphine, tris (trimethylsilyl) arsine, hydrogen sulfide, selenium Periodic table of hydrogen fluoride, hydrogen telluride, etc.
Periodic Table 1 of hydrides of group elements, bis (trimethylsilyl) sulfide, bis (trimethylsilyl) selenide, etc.
Alkali metal salts of Group 16 elements such as silylated compounds of Group 6 elements, sodium sulfide, sodium selenide, etc., tributylphosphine sulfide, trihexylphosphine sulfide, trioctylphosphine sulfide, tributylphosphine selenide, trihexylphosphine selenide , Trialkylphosphine chalcogenides such as trioctylphosphine selenide, hydrides of Group 17 elements of the periodic table such as hydrogen fluoride, hydrogen chloride, hydrogen bromide, hydrogen iodide, trimethylsilyl chloride, trimethylsilyl bromide, trimethylsilyl iodide, etc. Periodic Table No. 17
Group-containing silylated products. Among them, in terms of reactivity, stability and operability of compounds, phosphorus, arsenic, antimony, bismuth, sulfur, selenium, tellurium, iodine and the like, a simple substance of Group 15 to 17 elements of the periodic table, tris (trimethylsilyl) Phosphine, tris (trimethylsilyl) arsine, etc., a silylated product of a Group 15 element of the periodic table, hydrogen sulfide,
Hydrides of Group 16 elements such as hydrogen selenide and hydrogen telluride; silylates of Group 16 elements such as bis (trimethylsilyl) sulfide and bis (trimethylsilyl) selenide; sodium sulfide; sodium selenide; Alkali metal salts of Group 16 elements of the periodic table, tributylphosphine sulfide, trihexylphosphine sulfide, trioctylphosphine sulfide, tributylphosphine selenide, trihexylphosphine selenide,
Trialkyl phosphine chalcogenides such as trioctyl phosphine selenide, silylated products of Group 17 elements of the periodic table such as trimethylsilyl chloride, trimethylsilyl bromide and trimethylsilyl iodide are preferably used, among which phosphorus, arsenic, antimony, sulfur, selenium Periodic elements such as simple substances of elements of groups 15 and 16 of the periodic table, tris (trimethylsilyl) phosphine, tris (trimethylsilyl) arsine, and the like, silylated products of group 15 elements of the periodic table, bis (trimethylsilyl) sulfide, bis (trimethylsilyl) selenide, etc. Table 16 Alkali metal salts of Group 16 elements such as silylated products of Group 16 elements, sodium sulfide, sodium selenide, etc., tributylphosphine sulfide, trioctylphosphine sulfide, tributylphosphine selenide, Trialkyl phosphine chalcogenide such as trioctylphosphine selenide, etc. are particularly preferably used.

In the hot soap method, which is a particularly preferred liquid phase production method, there is no limitation on the supply rate of the raw material compound to the reaction liquid phase. It may be preferable to inject a predetermined amount in a short time of about 1 to 60 seconds. The appropriate crystal growth reaction time (residence time in the case of the flow method) after the injection of the raw material solution varies depending on the type of semiconductor, the desired particle size, or the reaction temperature.
The reaction temperature is about 350 ° C. for about 1 minute to 10 hours.

In such a hot soap method, isolation and purification are usually performed after the completion of the growth reaction of the semiconductor crystal. As this method, concentration of liquid phase components or precipitation method is suitable. A preferred representative procedure of the precipitation method is as follows. That is, after cooling to a temperature not reaching the solidification temperature of the reaction solution, toluene or hexane is added to suppress solidification at room temperature, and then a poor solvent for the semiconductor ultrafine particles, for example, methanol, ethanol, n-propanol, isopropyl alcohol , N
-A procedure in which ultrafine semiconductor particles are precipitated by mixing with lower alcohols such as butanol or water, and separated by physical means such as centrifugation or decantation. It is possible to further increase the purification degree by dissolving the precipitate thus obtained in toluene, hexane or the like again and repeating the procedure of precipitation and separation. The precipitation solvent may be a mixed solvent.

[Binding of Hyperbranched Molecules to the Surface of Ultrafine Semiconductor Crystal Particles] An example of a preferred method of introducing the above hyperbranched molecules into the ultrafine semiconductor crystal particles obtained by any of the manufacturing methods exemplified above is described below. This will be described below. (A) Method by Ligand Exchange Reaction Ultrafine semiconductor crystal particles to which a ligand having a relatively weak coordination force (hereinafter referred to as a “weak ligand”) such as an amino group, a phosphine oxide group, or a phosphine group are bound By contacting the desired hyperbranched molecule with the weak ligand in an excess molar number in a liquid phase containing semiconductor ultrafine particles, the weak ligand can be replaced by the desired hyperbranched molecule. There may be. In particular, when the desired hyperbranched molecule has a functional group having a strong coordination force such as a mercapto group, such a ligand exchange reaction proceeds extremely well.

A first step of dispersing in a liquid phase containing a large excess (usually used as a solvent) of a weakly coordinating compound such as pyridine, followed by a desired hyperbranched molecule (preferably a strong molecule such as a mercapto group) In some cases, ligand exchange by a two-step process comprising a second step of adding a hyperbranched molecule having a functional focal point functional group) is preferred. The ligand exchange reaction is usually performed in a temperature range of about −10 to 200 ° C., and preferably in a temperature range of about 0 to 170 ° C., more preferably about 0 to 170 ° C. in order to avoid thermal degradation of the organic substance and incomplete completion of the exchange reaction. Is about 10 to 140 ° C., most preferably 20 to 120 ° C.
About ℃. In addition, the reaction time of each step depends on the raw materials and the temperature.
0 hours, preferably 5 minutes to 70 hours, more preferably 1 hour
It is about 0 minute to 50 hours, most preferably about 10 minutes to 30 hours.

The ligand exchange reaction is preferably performed in an atmosphere of an inert gas such as nitrogen or argon in order to avoid side reactions such as oxidation. In some cases, not only the ligand exchange reaction but also the post-treatment process for producing ultrafine particles is preferably carried out under light-shielding conditions. After such ligand exchange reaction, in order to isolate the product, filtration, combined use of precipitation and centrifugation, distillation, any method such as sublimation may be used,
Particularly effective is a combination of precipitation and centrifugation utilizing the fact that the specific gravity of a semiconductor crystal is larger than that of a normal organic compound. Centrifugation is performed by throwing the solution after the ligand exchange reaction into a poor solvent of the semiconductor crystal ultrafine particles of the present invention having a hyperbranched molecule as a ligand, and centrifuging a suspension containing a generated precipitate. Done. The obtained precipitate is separated from the supernatant by decantation or the like, and if necessary, washing with a solvent, re-dissolution and re-precipitation / centrifugation are repeated to improve the degree of purification. The rotation speed of the centrifugation is usually about 100 to 8000 rotations per minute, preferably about 300 to 6000 rotations per minute, more preferably about 500 to 4000 rotations per minute, and most preferably about 700 to 3000 rotations per minute. Is usually -10 to 1
It is carried out at a temperature of about 00 ° C, preferably about 0 to 80 ° C, more preferably about 10 to 70 ° C, and most preferably about 20 to 60 ° C. In some cases, it is desirable that the purification step is performed in an inert gas atmosphere such as nitrogen or argon in order to avoid side reactions such as oxidation. (B) Method of bonding hyperbranched molecules by a chemical reaction of surface functional groups This method utilizes a chemical reaction of a functional group (hereinafter, referred to as “surface reaction point”) present on the surface of the semiconductor crystal ultrafine particles.
The chemical reaction referred to here is a reaction for generating a covalent bond between the surface functional group and the hyperbranched molecule, and is different from the ligand exchange reaction. Such methods are broadly classified into two methods. The first is a method in which a hyperbranched molecule that has already been completed is reacted with and bonded to the surface reaction point, and the second is to synthesize a hyperbranched molecular skeleton from the surface reaction point. Is the way.

As the first method, for example, the number of generations of the skeleton of the polybenzyl ether dendron can be increased by a condensation reaction between a phenolic hydroxyl group and a benzyl bromide structure existing at the focal point of the dendron. Therefore, a molecule having a phenolic hydroxyl group and a ligand (for example, 4-mercaptophenol, 3,5-dihydroxybenzenethiol, etc.) on the surface of the semiconductor crystal is first bonded to the surface of the semiconductor crystal, and then a benzyl bromide structure is formed. Potassium carbonate / 18
By performing the reaction in the presence of an appropriate base such as a crown-6 ether system, the dendron can be bonded to the semiconductor crystal surface by a new benzyl ether bond.

As the second method, for example, the PA
MAM dendrimers and polypropyleneimine dendrimers are synthesized by the so-called Divergent method (a synthesis strategy of expanding and synthesizing a hyperbranched structure from the focal point to the outside) by the Michael addition reaction of amino groups to acrylonitrile. A molecule having a ligand and an amino group (eg, 4-aminobenzenethiol) is first bonded to the surface of the semiconductor crystal, and then acrylonitrile is acted on the amino group, thereby constructing the dendron skeleton on the surface of the semiconductor crystal. It is possible.

The progress of the chemical reaction on the surface of the semiconductor crystal can be confirmed by, for example, the presence of a dendron structure by NMR or IR, or the detection of an organic component increased by the binding of the dendron by thermogravimetric analysis. (C) Addition to a semiconductor crystal formation reaction liquid phase A method of adding a coordinating hyperbranched molecule to a semiconductor crystal formation reaction liquid phase by the liquid phase method such as a hot soap method, a reverse micelle method, or a sol-gel method. is there. In the case of the hot soap method, a hyperbranched molecule suitable for such a method is one having a phosphine group or a phosphine oxide group such as the above-mentioned phosphine dendron or phosphine oxide dendron, and the latter is particularly optimal. In the case of the reverse micelle method or the sol-gel method, a dendron having a mercapto group is also preferably used. The addition of such a coordinating hyperbranched molecule is preferably performed at a later stage of the semiconductor crystal formation reaction. The reason for this is that after the semiconductor crystal ultrafine particles of a desired size are generated, a coordinating hyperbranched molecule is coordinated on the surface thereof. The timing of the addition of such a hyperbranched molecule is arbitrarily selected depending on the desired semiconductor crystal grain size.
10 nm, preferably 2-8 nm, more preferably 2.
It is at the time when it has grown to about 5 to 7 nm. In order to suppress undesired thermal decomposition of the hyperbranched molecule and to secure sufficient coordination reactivity, the reaction temperature during the addition is usually 20 to
The range is 300 ° C., preferably 40 to 250 ° C., more preferably 60 to 200 ° C., and most preferably about 80 to 150 ° C. In such a method, a post-treatment similar to that described in the above (A), that is, a step of isolating the product is usually performed.
Again, a combination of precipitation and centrifugation is particularly preferred.

[Thin Film-Shaped Compact Containing Ultrafine Particles] In order to utilize any useful property of the semiconductor crystal ultrafine particles of the present invention, it is very useful to form a thin film-shaped compact. Such useful properties include absorption and / or emission in the ultraviolet, visible, near-infrared, and infrared regions, and absorption and scattering of electromagnetic waves in general, including not only light in these various wavelength regions but also X-rays and gamma rays. Examples include the property of diffracting and interfering, and the property of absorbing, scattering, diffracting, and interfering elementary beams such as electron beams and neutron beams.

There is no particular limitation on the method for obtaining such a thin film-shaped molded product, but for example, a general-purpose method such as applying and drying a liquid containing ultrafine semiconductor crystal particles of the present invention onto a substrate (if necessary) An optional process such as heating or deformation may be added). Such a liquid may be a visually uniform solution or an emulsion or suspension. The solvent used for preparing such a liquid is not particularly limited as long as it has a necessary affinity for the ultrafine particles used.

The concentration of the liquid containing the ultrafine semiconductor crystal particles of the present invention is not particularly limited, and varies depending on the coating method, the intended film thickness, etc., but is usually 0.01 to 1%.
000 mg / mL, preferably 0.1-100 mg / m
It is about L. The substrate used is not particularly limited,
For example, inorganic substances such as metals, metal oxides, ceramics, and compound semiconductors, organic substances such as various polymers and paper, or liquid surfaces such as water, alcohols, and mercury can be used. Among them, it is preferable to use inorganic substances such as metals, metal oxides, ceramics, and compound semiconductors, or polymers in view of the stability of the obtained thin film.

As a method of applying to the substrate, a general method such as a spin coating method, a dip coating method, a wetting film method, and a spray coating method can be used. Such a thin film-shaped molded product is formed by hydrolysis and condensation of a styrene resin such as polystyrene, an acrylic resin such as polymethyl methacrylate, a transparent resin matrix such as an aromatic polycarbonate resin, or a metal alkoxide such as tetraethoxysilane (so-called sol. -Gel method), a composition obtained by dispersing the ultrafine semiconductor crystal particles of the present invention in a transparent matrix material such as a glass matrix such as silica synthesized by silica or the like may be formed into a film. In this case, a matrix material such as a transparent resin may be previously dissolved in a liquid containing the semiconductor crystal ultrafine particles of the present invention, and then coated and dried on a base material to form a film, Alternatively, the ultrafine semiconductor crystal particles of the present invention may be previously dissolved or dispersed in a solution containing a metal alkoxide such as tetraethoxysilane, and then a sol-gel reaction may be performed to form a film as a glass matrix composition. .

In addition to the method described above, when the ultrafine particles used or a composition obtained by dispersing the ultrafine particles in a transparent resin matrix or the like has thermoplasticity, a T-die molding method may be used.
A general-purpose heat-melt extrusion film forming method such as a blow molding method and an inflation molding method can be applied. The film thickness, size, shape, and surface properties (eg, attributes such as flat, spherical, curved, concave, convex, porous surfaces, smoothness, and thickness distribution) of the resulting film are Although there is no particular limitation, for example, the film thickness is usually 1 to 100,000 nm, preferably 1 to 10,000 nm, more preferably 1 to 100 nm.
It is about 1,000 nm.

An optional additive, for example, a stabilizer such as an antioxidant, a heat stabilizer, or a light stabilizer, may be added to the thin film-shaped product containing the ultrafine particles of the present invention obtained as described above.
Fillers such as glass fiber, glass beads, mica, talc, kaolin, clay mineral, carbon fiber, carbon black, graphite, metal fiber, metal powder, antistatic agent, release agent,
Additives such as plasticizers, ultraviolet absorbers, coloring agents such as pigments and dyes, impact-resistance imparting agents such as rubber and elastomers, and thermoplastic resins may be mixed with optional additives as necessary. It is possible.

[0064]

EXAMPLES Hereinafter, specific embodiments of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples unless it exceeds the gist thereof.
The raw material reagents are Aldric unless otherwise specified.
The product of Company h was used without purification. However, some solvents were purified as follows.

Toluene: concentrated sulfuric acid, water, saturated aqueous sodium bicarbonate,
After washing with water in order, the extract was dried over anhydrous magnesium sulfate, filtered through filter paper, and distilled from diphosphorus pentoxide (P ₂ O ₅ ). Methanol: After drying with calcium sulfate and calcium hydride, sodium hydride was further added, followed by direct distillation. n-Butanol: Directly distilled after drying with calcium sulfate and calcium oxide.

[0066] Measurement apparatus and conditions, etc.] (1) Nuclear magnetic resonance spectrum (NMR): JEOL Ltd. JNM-EX270 type FT-NMR ⁽¹ H: 270MH
z, ¹³ C: 67.8 MHz). The solvent used was deuterated chloroform unless otherwise specified. Measured at 23 ° C. (2) Infrared absorption spectrum (FT-IR): FT / IR-8000 type FT-IR manufactured by JASCO Corporation. Measured at 23 ° C. (3) Mass spectrometry (MALDI-TOF-MS): KOMPACTMALDI III laser ionization TOF-MS manufactured by Shimadzu Corporation. (4) X-ray diffraction spectrum (XRD): RINT 1500 manufactured by Rigaku Corporation (X-ray source: copper Kα ray, wavelength 1.541)
8Å). (5) Transmission electron microscope (TEM): Hitachi, Ltd.
H-9000UHR transmission electron microscope (acceleration voltage 30
0 kV, degree of vacuum at the time of observation is about 7.6 × 10 ⁻⁹ Torr). (6) Photoexcitation emission spectrum (PL): F-2500 type spectrofluorimeter manufactured by Hitachi, Ltd., scan speed 60 nm / min, excitation side slit 5 nm, fluorescence side slit 5 nm, photomultiplier voltage 400 V The measurement was performed using a quartz cell having an optical path length of 1 cm.

[Preparation of dendritic benzyl bromide] J. Hawker et al .; Am. Che
m. Soc. , 112, 7638 (1990), it is possible to synthesize dendritic benzyl bromide having a polybenzyl ether structure having a 3,5-dioxybenzyl residue as a repeating unit. In the present invention, the first generation dendritic benzyl bromide, 3,5-bis (benzyloxy)
Benzyl bromide (hereinafter abbreviated as [G-1] -Br) and 3,5-bis [3,5-bis (benzyloxy) benzyloxy] benzyl bromide, a second-generation dendritic benzyl bromide (hereinafter referred to as [G -2] -Br) used in each case was supplied by Tokyo Chemical Industry Co., Ltd. 3,5-bis {3,5-bis [3,5-bis (benzyloxy) benzyloxy] benzyloxy}, a third generation dendritic benzyl bromide
Benzyl bromide (hereinafter abbreviated as [G-3] -Br) was synthesized as follows. That is, [G-2] -Br
(2.05 eq.), 3,5-dihydroxybenzyl alcohol (1.0 eq.), And 18-crown-6 ether (0.2 eq.) Were dissolved in dry acetone and freshly ground anhydrous potassium carbonate (2 eq.). .5 eq.) And heated in a dry nitrogen atmosphere to give a third
3, the next generation of dendritic benzyl alcohol
Thus, 5-bis {3,5-bis [3,5-bis (benzyloxy) benzyloxy] benzyloxy} benzyl alcohol (hereinafter abbreviated as [G-3] -OH) was obtained. Purified by recrystallization from a methanol / ethyl acetate system [G-3]-
OH is then dissolved in a minimum amount of dry tetrahydrofuran with carbon tetrabromide (1.25 equivalents) and [G-3] -Br is obtained by a bromination reaction in which triphenylphosphine (1.25 equivalents) is added while cooling with ice. To methanol /
It was purified by recrystallization from ethyl acetate. This structure is ¹
H and ¹³ C-NMR spectrum and FT-IR spectrum are as described in the above C.I. J. It was confirmed from the agreement with the report by Hawker et al.

[Synthesis of Dendritic Benzyl Bromide Terminaled with 4-Vinylphenyl Group] Benzyl bromide (1.
0 eq), 3,5-dihydroxybenzyl alcohol (1.0 eq), and 18-crown-6 ether (0.2 eq) in dry acetone and freshly ground anhydrous potassium carbonate (2.5 eq) ) And heated at 60 ° C. with stirring in a dry nitrogen atmosphere. Merc
k thin-layer silica gel chromatography (TL
The reaction was followed by C), and after confirming the disappearance of benzyl bromide, 4-vinylbenzyl chloride (1.0 equivalent), tetraethylammonium bromide (1.0 equivalent), and a catalytic inhibitor of 2,6 equivalents as a polymerization inhibitor. -Ji-te
rt-Butyl-4-methylphenol was added, and the reaction was continued under the same conditions. After confirming the disappearance of 4-vinylbenzyl chloride by TLC, the reaction solution was concentrated, separated between two phases of water and methylene chloride, and the obtained organic phase was washed with water, dried (anhydrous sodium sulfate), filtered, and After concentration, the obtained residue was purified by silica gel column chromatography. The first-generation dendritic benzyl alcohol thus obtained was combined with carbon tetrabromide (1.25 equivalents) and triphenylphosphine (1.
(25 equivalents) to give the corresponding first generation dendritic benzyl bromide. The reaction solution was poured into a large amount of ice water, extracted with methylene chloride, the organic phase was washed with water, dried (anhydrous sodium sulfate), filtered, and concentrated. The obtained residue was purified by silica gel column chromatography and recrystallization. By repeating these two kinds of reactions, it is possible to increase the number of generations of polybenzyl ether dendron having a 4-vinylphenyl group at a terminal.

When the ¹ H-NMR spectrum of this product was measured, a vinyl group (3 protons), a terminal phenyl group (4 protons) having a 4-vinyl group bonded thereto, a phenyl group (5 protons), and a benzene at the focal point Ring (3
Protons) and each of the protons assigned to the benzyl position (total of 6 protons) are observed at reasonable integration values, and the chemical shift of the benzyl position proton at the focal point is about 4.3 ppm, which is a typical benzyl bromide structure. Given the values, generation of the first-generation dendritic benzyl bromide (hereinafter abbreviated as V- [G-1] -Br) in which one end is a 4-vinylphenyl group was confirmed.

[Synthesis of thiol dendron] Using the dendritic benzyl bromide synthesized above, Z. Bo et al .; Chem. Lett. , P. 1197 (1
998), a thiol dendron having a polybenzyl ether structure having first and second generation 3,5-dioxybenzyl residues as repeating units was synthesized.

<Synthesis Example 1> An excess of thiourea in excess of [G-1] -Br, which is the above-mentioned first-generation dendritic benzyl bromide, was mixed by heating under reflux in a nitrogen atmosphere with ethanol / tetrahydrofuran (1: 2). The mixture was allowed to act in a solvent for 4 hours, and then an aqueous solution containing a small excess of potassium hydroxide relative to the added thiourea was added, and the mixture was further heated under reflux for 4 hours. The reaction solution was concentrated to remove the organic solvent, and the resulting aqueous alkaline solution was added dropwise to ice-cooled diluted hydrochloric acid (containing an excess of hydrogen chloride in excess of potassium hydroxide used) with stirring. The organic phase obtained by extracting the precipitate with methylene chloride is washed with water, dried over anhydrous sodium sulfate, filtered and concentrated, and the residue obtained is dried using a mixed solvent of n-hexane / methylene chloride / diethyl ether as a developing solvent. Purification by silica gel flash column chromatography under nitrogen pressure to obtain a first-generation thiol dendron (hereinafter abbreviated as [G-1] -SH) in which L in Formula (1) corresponds to a mercapto group (-SH). Was. This structure
¹ H and ¹³ C-NMR spectra showed signals of proton or carbon assigned to a terminal phenyl group, a benzene ring at a focal point, and two kinds of benzyl positions, respectively, and an FT-IR spectrum of around 2570 cm ^-1. The absorption band attributed to the mercapto group was observed, and the peak given by the target structure was observed in the MALDI-TOF-MS spectrum. Since this synthetic product was easily oxidized, it was refrigerated and stored under a light-shielded condition in a dry nitrogen atmosphere until immediately before the next use.

<Synthesis Example 2> [G-1] in Synthesis Example 1
The same synthetic operation was performed using [G-2] -Br, which is the above-mentioned second-generation dendritic benzyl bromide, in place of -Br, and the above-mentioned Z.-Br. A second generation thiol dendron having a synthesis example in Bo et al. Was synthesized (hereinafter abbreviated as [G-2] -SH). This compound is a compound in which L in the general formula (2) corresponds to a mercapto group (-SH), and various spectrum measurement values similar to those in Synthesis Example 1 are obtained from Z.I. The structure was confirmed from the agreement with the literature by Bo et al. Since this synthetic product was easily oxidized, it was refrigerated and stored under a light-shielded condition in a dry nitrogen atmosphere until immediately before the next use.

<Synthesis Example 3> [G-1] in Synthesis Example 1
A similar synthetic operation was performed using the first-generation dendritic benzyl bromide V- [G-1] -Br in which one end was a 4-vinylphenyl group instead of -Br to obtain the corresponding one end. Is a 4-vinylphenyl group
Generation of thiol dendrons (hereinafter V- [G-
1] -SH). This structure, vinyl group in ¹ H-NMR spectrum, 4-vinyl group bound phenyl group, a phenyl group, the focal point benzene ring,
A proton signal assigned to each of the benzyl positions was observed, and in the FT-IR spectrum, 2
It was confirmed from the fact that an absorption band attributed to a mercapto group was observed at around 570 cm ⁻¹ , and furthermore, from the MALDI-TOF-MS spectrum that a peak given by the target structure was observed. Since this synthetic product was easily oxidized, it was refrigerated and stored under a light-shielded condition in a dry nitrogen atmosphere until immediately before the next use.

[Synthesis of Ultrafine Semiconductor Crystal Particles] <Synthesis Example 4: Synthesis of Ultrafine ZnSe Crystalline Particles> Hexadecyl was placed in a brown glass three-necked flask equipped with an air-cooled Liebig reflux tube and a thermocouple for controlling the reaction temperature. The amine (8.6 g) was added, and the mixture was stirred for 3 hours with a magnetic stirrer while heating to 125 ° C. under vacuum, and preliminarily dried. During this time, the inside was replaced with dry argon gas several times.
Separately, in a glove box in a dry nitrogen atmosphere, a 1N concentration of diethyl zinc solution in n-hexane (0.91 m
L), selenium trioctylphosphine (abbreviated as TOP)
Solution (6.16% by weight, 1.463 g) and additional T
OP (4 mL) was wrapped tightly in aluminum foil and mixed in a light-shielded glass container to obtain a raw material solution. Reflux pipes and joints are wrapped tightly in aluminum foil to shield light, and kept at atmospheric pressure under argon gas atmosphere.
The temperature was raised to 20 ° C. While the stirring was continued, the above-mentioned raw material solution was injected at once by a syringe, and this time was regarded as the start of the reaction time. At this time, care must be taken because low-boiling organic substances such as n-hexane and decomposition products from the raw materials are vaporized at a stretch and pass through the reflux tube. Immediately thereafter, the temperature was set at 290 ° C. At 166 minutes after the start of the reaction, 12
Trioctylphosphine oxide (abbreviated as TOPO, approximately 5 mL) which had been heated and stirred under vacuum at 5 ° C. was added with a syringe, and the heat source was immediately removed and air-cooled. Toluene (5 mL) was added thereto with a syringe to dilute the mixture, and the mixture was allowed to cool to room temperature. This solution was added dropwise to a mixed solvent (40 mL) of methanol and n-butanol in an equal volume under a dry nitrogen atmosphere while stirring, and the insolubles were centrifuged (4000 rpm).
Minutes). The precipitate obtained by removing the supernatant by decantation was washed with the above mixed solvent, and the supernatant was removed again by decantation to obtain precipitated ultrafine particles. The powder obtained by drying and solidifying the ultrafine particles thus obtained was subjected to the XRD measurement. The diffraction peaks attributed to the 220 and 311 planes of the ZnSe crystal were observed, thereby confirming the formation of ZnSe nanocrystals. Also,
The TEM observation of the ZnSe ultrafine particles revealed that the ultrafine particles had an average particle diameter of 5 nm.

<Synthesis Example 5: Synthesis of Ultra Fine CdS Crystal Particles>
Using the reaction apparatus of Synthesis Example 4, trioctylphosphine oxide (abbreviated as TOPO,
4.0 g) and the inside was replaced with a dry argon atmosphere. Thereafter, the reaction temperature was set to 300 ° C., and stirring was started with a magnetic stirrer. The reaction system was covered with aluminum foil and shielded from light as in Synthesis Example 4. Liquid phase TOPO
Is stabilized at 300 ° C., a 10% concentration n-hexane solution (0.60%) of dimethylcadmium, which is a raw material solution separately prepared in a glove box in a dry nitrogen atmosphere.
g) and bis (trimethylsilyl) sulfide (0.03
0g) with tributylphosphine (hereinafter abbreviated as TBP, 2.
75 g) was injected at once with a syringe. This time was the start of the reaction time. At this time, care must be taken because low-boiling organic substances such as n-hexane and decomposition products from the raw materials are vaporized at a stretch and pass through the reflux tube. 1 after the start of the reaction
The heat source was removed over time, and the mixture was air-cooled. When cooled to about 60 ° C., methanol (0.5 mL) was added, and the mixture was allowed to cool to room temperature. This solution was put into methanol (15 mL) with stirring under a dry nitrogen atmosphere, and stirring was continued for 5 minutes. The insoluble material was centrifuged (4000 rpm / min, 3 minutes), and the supernatant obtained by removing the supernatant by decantation was redissolved in toluene (1.5 mL). This solution was dropped into methanol (10 mL) in the same manner as described above to produce a precipitate, which was subjected to centrifugation and then decantation to obtain a precipitate. By XRD measurement of the powder obtained by drying and solidifying the ultrafine particles thus obtained, a CdS crystal of 00 was obtained.
Since the diffraction peaks attributed to two planes were observed, CdS
The formation of nanocrystals was confirmed. This CdS ultrafine particle is TE
M observation revealed that the particles were ultrafine particles having an average particle diameter of 6 nm.

<Synthesis Example 6: Synthesis of Ultrafine CdSe Crystalline Particles> In Synthesis Example 5, the temperature inside the first flask containing TOPO (4.0 g) was set at 350 ° C. to stabilize the temperature.
Separately, in a glove box in a dry nitrogen atmosphere, a raw material solution obtained by adding a 10% concentration n-hexane solution (2.18 g) of dimethylcadmium to a solution of selenium (single unit; 0.10 g) dissolved in TBP (4.38 g). Was prepared.
Immediately before the injection of the raw material solution, the reaction temperature was set to 300 ° C., and a part (2 mL) of the raw material solution was injected into the flask at once with a syringe, and this time was defined as the start of the reaction time. At this time, care must be taken because low-boiling organic substances such as n-hexane and decomposition products from the raw materials are vaporized at a stretch and pass through the reflux tube. The heat source was removed 30 minutes after the start of the reaction.
A similar post-processing operation was performed. The XRD measurement of the powder obtained by drying and solidifying the ultrafine particles thus obtained showed diffraction peaks belonging to the 002 plane and the 110 plane of the CdSe crystal, thereby confirming the formation of CdSe nanocrystals. This C
TEM observation of the dSe ultrafine particles revealed that the particles were ultrafine particles having an average particle diameter of 4 nm.

<Synthesis Example 7: CdS having ZnS shell>
Synthesis of semiconductor ultrafine particles mainly composed of e-nanocrystal> T in a three-neck flask made of brown glass in a dry argon gas atmosphere
OPO (15 g) was added, and the mixture was stirred in a molten state at 130 to 150 ° C. under reduced pressure for about 2 hours. During this time, an operation of returning to atmospheric pressure with dry argon gas was performed several times in order to replace the remaining air and moisture. After about 1 hour with the temperature set to 100 ° C., a TOP (1.5 g) solution of the solid powder of CdSe nanocrystals (0.094 g) obtained in Synthesis Example 6 was added to obtain a transparent solution containing CdSe nanocrystals. Was. This one
After stirring under reduced pressure of 00 ° C. for about 80 minutes, the temperature was increased to 180 ° C.
C. and the pressure was restored to atmospheric pressure with dry argon gas. Separately, a 1N-concentration n-hexane solution of diethyl zinc (1.34 mL;
34 mmol) and bis (trimethylsilyl) sulfide (0.239 g; 1.34 mmol) in TOP (9 m
The raw material solution B dissolved in L) was sealed in a septum, wrapped tightly in aluminum foil, and prepared in a light-shielded glass bottle. This raw material solution B was mixed with the above 180
The solution was dropped into a transparent solution containing CdSe nanocrystals at 20 ° C. over 20 minutes. After the temperature was lowered to 90 ° C., stirring was continued for about 1 hour. After standing at room temperature for about 14 hours, the mixture was again heated and stirred at 90 ° C. for 3 hours. The heat source was removed and n-butanol (8 mL) was added to the reaction and cooled to room temperature to give a clear red solution.
This red solution had no odor of a sulfur compound such as bis (trimethylsilyl) sulfide as a raw material, but instead had a leek-like odor peculiar to selenium. Since the solution of CdSe nanocrystals obtained in Synthesis Example 6 did not have such selenium odor,
With the progress of the intended sulfide generation reaction on the surface of the CdSe nanocrystal, it is presumed that selenium was released by some mechanism such as a substitution reaction of a selenium atom with a sulfur atom on the surface of the nanocrystal. ZnS
It was considered that semiconductor ultrafine particles mainly composed of CdSe nanocrystals having a shell were generated (hereinafter referred to as CdS nanocrystals).
e / ZnS-TOPO). A part (8 mL) of this red solution was dropped into methanol (16 mL) at room temperature under a stream of dry nitrogen, and a red insoluble material was obtained by a precipitation operation in which stirring was continued for 20 minutes. Synthesis Example 2
Similarly, it was separated by centrifugation and decantation, and redissolved in toluene (14 mL). Using this re-dissolved toluene solution, a similar series of purification operations including precipitation, centrifugation, and decantation was performed again to obtain a solid product. This solid product was shaken with 1 mL of purified methanol, washed, and separated by decantation. This solid product gives a clear red toluene solution in which 46
Irradiation with excitation light having a wavelength of 8 nm gave an orange emission band (peak wavelength: 597 nm, half width: 41 nm).
At a similar solution concentration, the luminescence was clearly higher than the luminescence intensity of the CdSe nanocrystal obtained in Synthesis Example 6, so that the luminescence was converted to a CdSe nanocrystal having a ZnS shell and passed through a surface level and the like. It was considered that the contribution of the non-light emitting process was suppressed.

Example 1 Ligand Exchange with Synthesized Dendron Example 1 Ultrafine ZnSe crystals obtained in Synthesis Example 4 were dissolved in toluene in a dry nitrogen atmosphere and heated to 100 ° C. First generation thiol dendron [G-
1] An excess amount of -SH is added and the reaction is carried out with stirring for 3 hours or more. When the reaction solution is poured into methanol with stirring, insolubles are produced. When this suspension is centrifuged, a precipitated insoluble matter and a non-precipitable insoluble matter are generated. Therefore, only the precipitateable insoluble matter is separated by decantation and redissolved in toluene. The re-dissolved toluene solution thus obtained is poured into methanol, subjected to the same centrifugation, and then subjected to a series of purification operations of separating the precipitated insoluble matter consisting of decantation, until the non-precipitable insoluble matter is not seen after being poured into methanol. Repeat (the non-precipitable insolubles found here are presumed to be unreacted thiol dendron [G-1] -SH).

The solubility of the final precipitation product in toluene is:
It is much better than the ultrafine ZnSe crystal particles obtained in Synthesis Example 4. Such a toluene solution can be cast and dried on a glass plate to obtain a good thin film. Further, the NMR spectrum of the final precipitation product gives signals of aromatic and benzylic protons of polybenzyl ether dendron, and thus substantially contains free or unreacted thiol dendron [G-1] -SH. Instead of [G-1] -SH as a ligand bound to the surface
It is considered to be e-crystal ultrafine particles.

Example 2 In Example 1, the ultrafine CdS crystal obtained in Synthesis Example 5 was replaced with the [G-1] -SH
The same experiment is performed using the second-generation thiol dendron [G-2] -SH obtained in Synthesis Example 2 in place of, to obtain a final precipitated product. The solubility of this final precipitation product in toluene is much better than the ultrafine CdS crystal particles obtained in Synthesis Example 5. Such a toluene solution can be cast and dried on a glass plate to obtain a good thin film. Since the NMR spectrum of the final precipitate gives signals of aromatic and benzylic protons of polybenzyl ether dendron, the final precipitate is free or unreacted thiol dendron [G-2]. [G-2] containing substantially no SH
It is considered to be a CdS crystal ultrafine particle bonded to the surface using SH as a ligand.

Example 3 The same experiment as in Example 1 was carried out except that the ultrafine CdSe crystal particles obtained in Synthesis Example 6 were used instead of the ultrafine ZnSe crystal particles, to obtain a final precipitated product. The solubility of this final precipitation product in toluene is much better than the ultrafine CdSe crystal particles obtained in Synthesis Example 6. Such a toluene solution can be cast and dried on a glass plate to obtain a good thin film. Since the NMR spectrum of this final precipitate gives signals of aromatic and benzylic protons of polybenzyl ether dendron, this final precipitate is free or unreacted thiol dendron [G-1]. [G-
1] It is considered to be ultrafine CdSe crystal particles bonded to the surface using -SH as a ligand.

Example 4 In Example 3, a first-generation thiol dendron V- [G-1] having a 4-vinylphenyl group at one end obtained in Synthesis Example 3 in place of [G-1] -SH. Perform similar experiments using -Br to obtain the final precipitated product. The solubility of this final precipitation product in toluene was determined by the Cd obtained in Synthesis Example 6.
It is much better than Se crystal ultrafine particles. Such a toluene solution can be cast and dried on a glass plate to obtain a good thin film. In addition, the N
Since the MR spectrum gives signals of aromatic, benzylic and vinyl group protons of polybenzyl ether dendron, it substantially contains free or unreacted thiol dendron V- [G-1] -SH. Instead of V- [G-1] -SH as a ligand bound to the surface
It is considered to be dSe crystal ultrafine particles.

Example 5 In Example 4, the core-shell type ultrafine particles CdSe / ZnS− obtained in Synthesis Example 7 were used instead of the ZnSe crystal ultrafine particles.
A similar experiment is performed using TOPO to obtain the final precipitated product. The solubility of this final precipitation product in toluene is:
It is much better than CdSe / ZnS-TOPO obtained in Synthesis Example 7. A good thin film can be obtained by casting and drying such a toluene solution on a glass plate, and the thin film has a property of emitting light when irradiated with, for example, ultraviolet light of a mercury lamp having a wavelength of 365 nm. The NMR spectrum of the final precipitation product gives signals of protons of aromatic, benzylic, and vinyl groups of polybenzyl ether dendron, so that free or unreacted thiol dendron V- [G-1 ] -SH is considered to be CdSe / ZnS core-shell type crystal ultrafine particles substantially free of -SH and bonded to the surface with V- [G-1] -SH as a ligand.

Example 6 Transparent Resin Composition and Thin Film Formed Thereof The ultrafine CdSe / ZnS core-shell type crystal grains obtained by bonding V- [G-1] -SH obtained in Example 5 as a ligand to the surface were prepared. Dissolved in styrene, 2,2'-azobisisobutyronitrile (commonly known as AIBN) was added as a radical initiator, and the solution was placed between two clean quartz plates with a thickness of about 0.1 mm.
A gap formed by interposing a 1 mm glass flat plate as a spacer is filled by capillary action, and when left at 90 ° C. in a nitrogen atmosphere, the polymerization reaction proceeds to give a thin film-shaped molded article of a transparent polystyrene composition. When the thin film thus obtained was irradiated with ultraviolet light having a wavelength of 365 nm using a mercury lamp, light emission was observed.

[Method of Bonding Dendron by Chemical Reaction of Surface Functional Group] <Synthesis Example 8: Synthesis of Ultra Fine CdS Crystal Particles> A 100 mL glass three-necked flask is wrapped in aluminum foil without gaps and light is shielded. TOPO (12 g) was charged and the inside was replaced with a dry argon atmosphere. Thereafter, the reaction temperature was increased to 3
The temperature was set to 00 ° C. and stirring was started with a magnetic stirrer. The reaction system was covered with aluminum foil and shielded from light as in Synthesis Example 4. When the TOPO in the liquid phase was stabilized at 300 ° C., a 10% concentration n of dimethylcadmium, which is a raw material solution separately prepared in a glove box in a dry nitrogen atmosphere, was used.
-Hexane solution (1.40 g) and bis (trimethylsilyl) sulfide (0.0825 mL) were added to TBP (5.6
25 g) was injected at once with a syringe. This time was the start of the reaction time. At this time, care must be taken because low-boiling organic substances such as n-hexane and decomposition products from the raw materials are vaporized at a stretch and pass through the reflux tube. After the reaction starts 2
At 0 minutes, the heat source was removed and air-cooled. After cooling to about 60 ° C., methanol (1.2 mL) was added, and the mixture was further allowed to cool to about 50 ° C., and stirred in methanol (45 mL) under a dry nitrogen atmosphere. I put in while. The obtained yellow precipitate was centrifuged (3000 rpm / minute, 3 minutes), and the supernatant obtained by removing the supernatant by decantation was used as a precipitate.
Redissolved in toluene (2 mL). This solution was added dropwise to methanol (30 mL) as above to produce a precipitate,
A precipitate was obtained by centrifugation and then decantation. The ultrafine particles thus obtained were dried and solidified (the yield after drying was 84.8 mg).

<Synthesis Example 9: CdS having ZnS shell>
Synthesis of semiconductor ultrafine particles mainly composed of nanocrystals> In a dry nitrogen atmosphere, the solid powder (0.060 g) of CdS nanocrystals obtained in Synthesis Example 8 and TOP (0.62 g) were mixed with n-
It was dissolved in hexane (0.5 mL) (hereinafter referred to as “CdS solution”). In a glove box in a dry nitrogen atmosphere, a 1N-concentration n-hexane solution of diethyl zinc (0.
75 mL) and bis (trimethylsilyl) sulfide (0.1574 mL) were dissolved in TOP (5 mL) to obtain a ZnS shell raw material solution. 50 made of brown glass
Put TOPO (6.2 g) in a 3-neck flask
In a molten state at 0 ° C., the mixture was stirred under a stream of dry argon and depressurized several times to replace and remove remaining air and moisture.
To this was added the CdS solution (rinse the vessel with an additional 2 mL of n-hexane and transfer completely), then reduce the pressure to n
-Hexane was distilled off. After the inside of the brown flask was set to a dry argon gas atmosphere and the liquid temperature was set to 210 ° C., the ZnS shell raw material solution was dropped therein for 29 minutes. After the dropping yield, the mixture was cooled to 90 ° C over 40 minutes, and stirring was continued at 90 ° C for 4 hours. After removing the heat source and cooling to near room temperature, n-
Butanol (3.3 mL) was added to the reaction, which was added to methanol (35 mL) with stirring to separate a yellow insoluble oil. The oil was centrifuged (4000
(Rpm / min) and decantation and redissolved in toluene (2 mL). The re-dissolved toluene solution was added to methanol (20 mL) with stirring to obtain a yellow precipitate, which was separated by centrifugation and decantation as described above. The yellow precipitate thus obtained was redissolved in toluene (2 mL) again, and methanol / n-
It was added to a mixture of butanol (10 mL / 10 mL) with stirring to obtain a yellow powder, which was separated by centrifugation and decantation as described above. The yellow powder was vacuum-dried at room temperature for 24 hours, and the core-shell type crystal ultrafine particles having a CdS crystal core and a ZnS shell (81.4 mg,
(Hereinafter abbreviated as CdS / ZnS-TOPO). The dried tetrahydrofuran (THF) solution of CdS / ZnS-TOPO thus obtained gave a broad emission band (half-width 127 nm) having a peak wavelength of 575 nm by irradiation with ultraviolet rays having a wavelength of 398 nm.

Examples 7 and 8: Bonding of polybenzyl ether dendron (2 types) to the surface of ultrafine semiconductor crystal particles via 4-mercaptophenol (hereinafter abbreviated as 4MP) Core-shell type crystal obtained in Synthesis Example 9 Ultra fine particles CdS / Zn
S-TOPO (15.8 mg) was added to dry THF (about 6 m
L). Part of this THF solution (0.9267)
g) was designated as "solution S" as a control sample, and sealed and stored. 4M in remaining THF solution (4.6304g)
P (53.1 mg, 0.421 mmol) was dissolved, dry THF (about 1 mL) was added thereto, and the mixture was dried under dry nitrogen atmosphere.
Stirred at C for 1 hour. After cooling this to room temperature,
The solution weight was 3.0 because some THF was lost by evaporation.
3387 g. This was subdivided into three, and each of “Solution A” (0.6580 g) and “Solution B” (1.33
87 g) and "Solution C" (1.3420 g). Solution A was sealed and stored as a sample to which only 4MP was acted. With respect to the remaining solution B and solution C, Will via a 4MP phenolic hydroxyl group was used as follows.
Reactions intended for binding of dendrons by iamson ether synthesis were performed. That is, in the solution B, dry THF (2
mL), 18-crown-6 ether (10.4 m
g), [G-1] -Br which is a first generation dendritic benzyl bromide (134.4 mg, 0.351
Mmol) and anhydrous potassium carbonate (61 mg immediately before crushed in a mortar) and stirred under a dry nitrogen atmosphere at 60 ° C. for 7.5 hours, while the solution C in the reaction using the solution B was [G-1 The above-mentioned [G-3]-, which is a third-generation dendritic benzyl bromide instead of -Br
The reaction was carried out under the same conditions except that Br (563.2 mg, 0.340 mmol) was used. Post treatment of these ether synthesis reactions was performed as follows. That is, the reaction solution is
The mixture was diluted with HF (5 mL) and filtered.
After washing three times with F (1 mL), the washing liquids were combined. The four kinds of THF solutions thus obtained are finally mixed with CdS as a raw material.
The weight was adjusted by appropriately adding dry THF so as to be 0.082 wt% in terms of / ZnS-TOPO, and PL measurement was performed one day later. FIG. 3 shows the emission spectrum obtained by the PL measurement. However, the excitation wavelength of each solution sample is
The solution S was 398 nm, the solution A was 399 nm, and the solution B was 3 nm.
86 nm and the solution C have a wavelength of 393 nm, and each of these excitation wavelengths is a wavelength that gives the maximum emission intensity in the excitation spectrum of each solution.

FIG. 3 shows that the raw material CdS / ZnS-T
When 4MP was allowed to act on OPO (solution S) (solution A), a remarkable decrease in luminescence intensity was observed, and the strong coordination ability of the thiol group of 4MP caused a ligand exchange reaction on the surface of CdS / ZnS-TOPO. It was considered advanced. When the dendron binding is attempted, the solution B, which is the result of reacting the first-generation dendron of Example 7, has a new emission band near 430 nm, which is considered to be light emission from an exciton level with a narrow half-value width. Clearly appears, and at the same time, a remarkable increase in the luminescence intensity as compared with the solution A in which only 4MP was acted is also confirmed from FIG. Since such a preferable luminous ability of enhancing the luminescence from the exciton level was remarkably exhibited, it was considered that the binding of the dendron via 4MP as shown in FIG. 4 progressed as expected. Such a change in the light emission behavior was slightly insignificant when the third-generation dendron of Example 8 was reacted.
Showed the same tendency. Although the reason for the difference in the emission behavior due to the difference in the number of generations is not clear, in the case of a large third-generation dendron, the number of molecules of the dendron actually bonded to the semiconductor crystal surface due to steric hindrance is smaller than that of the first-generation dendron. It is presumed that there is less. Therefore, in the case of Example 8, since a small number of dendrons are sparsely bonded to the semiconductor crystal surface, the change in the preferable electron level of the crystal surface caused by the bonding is smaller, or the excluded volume of the dendron (Site Exclusion) ) It is presumed that the effect is smaller and the influence of the external environment (for example, the coordination of THF molecule as a solvent) becomes remarkable.

[0089]

The ultrafine semiconductor crystal particles of the present invention are bonded to a dendrimer as a ligand, so that they have high solubility in a medium, good homogeneity of a thin film, and high chemical stability due to the shielding effect from the outside. Since it has excellent absorption and emission characteristics controlled by quantum effects, it provides ultra-high-density recording materials that use optical characteristics or optical materials that are used as light-emitting elements and optical waveguides. Used in fields such as computer and fluorescence diagnosis.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the structure of a dendrimer.

FIG. 2 is a schematic diagram showing coordination of hyperbranched molecules to ultrafine semiconductor crystal particles at a focal point.

FIG. 3 is a diagram showing a change in emission spectrum due to binding of a dendron to the surface of a core-shell type semiconductor crystal ultrafine particle.

FIG. 4 shows a graph of 4-
It is a schematic diagram which shows the binding reaction of a dendron via a mercaptophenol molecule.

Claims (12)

[Claims] 1. Ultrafine semiconductor crystal particles comprising a hyperbranched molecule bound as a ligand at its focal point. 2. The ultrafine semiconductor crystal particles according to claim 1, wherein the focal point functional group of the hyperbranched molecule contains a Group 15 or 16 element of the periodic table. 3. The ultrafine semiconductor crystal particles according to claim 1, wherein the semiconductor crystal contains an element belonging to Groups 12 to 17 of the periodic table. 4. The semiconductor according to claim 1, wherein the semiconductor is a II-VI compound semiconductor or III.
The semiconductor ultrafine particles according to any one of claims 1 to 3, which is a group V compound semiconductor. 5. The semiconductor crystal according to claim 1, wherein the semiconductor crystal has a core-shell structure, and the shell has a bandgap in a bulk state at a temperature of 300 K of 2.0 eV or more. 2. Ultrafine semiconductor crystal particles according to item 1. 6. The ultrafine semiconductor crystal particles according to claim 1, wherein the hyperbranched molecule has an aromatic group as a repeating unit. 7. The ultrafine semiconductor crystal particles according to claim 1, wherein the hyperbranched molecule has a dendrimer structure. 8. The ultrafine semiconductor crystal particles according to claim 1, wherein the hyperbranched molecule is polybenzyl ether dendron. 9. The ultrafine semiconductor crystal particles according to claim 1, which has a hyperbranched molecule having a carbon-carbon multiple bond at a non-focal point terminal as a ligand. 10. The ultrafine semiconductor crystal particles according to claim 1, wherein the focal point functional group of the hyperbranched molecule contains a phosphorus atom or a sulfur atom. 11. The method for producing ultrafine semiconductor crystal particles according to claim 1, further comprising a step of performing a ligand exchange reaction with a hyperbranched molecule. 12. A thin film-shaped compact containing the ultrafine semiconductor crystal particles according to claim 1.