JP2019108410A - Semiconductor nanoparticle, dispersion including the particle, semiconductor layer, production method of laminate, and electroluminescence element - Google Patents

Abstract

To provide: a dispersion of semiconductor nanoparticles, which has excellent dispersion stability, an excellent emission quantum yield and heat resistance, and which can form a semiconductor layer which can exhibit an emission quantum yield almost equal to that of the dispersion; to provide a semiconductor layer which has an excellent emission quantum yield and heat resistance by using the dispersion; and further to provide an electroluminescence element which has long life, excellent emission efficiency, and high relative luminance by using the dispersion.SOLUTION: Semiconductor nanoparticles 2 comprise semiconductor nanoparticles 1 of which at least a portion of the surfaces are covered with a ligand described below and of which the average particle diameter is 50 nm or less, in which the ligand has a main chain with no conjugated structure and a side chain bonded to the main chain, and in which the side chain has a conjugated structure and an adsorptive group.SELECTED DRAWING: None

Description

  The present invention relates to semiconductor nanoparticles, a dispersion containing the particles, a semiconductor layer, a method of manufacturing a laminate, and an electroluminescent device.

Electroluminescent elements (EL, ElectroLuminescence) have attracted attention as surface-emitting elements that are lightweight, thin, have low power consumption, and have excellent shape freedom. Such an electroluminescent element has many excellent features such as high luminance light emission, high-speed response, wide viewing angle, thin and light weight, high resolution, etc., and its application to flat panel displays and illumination is being studied.
In recent years, the use of so-called quantum dots has attracted attention as one of the electroluminescent elements.

Quantum dots are small particles in nanoscale, and exhibit an intermediate behavior between atomic or molecular behavior and behavior of macroscopic solid (bulk form). A nanoscale material (semiconductor nanoparticle) in which charge carriers and excitons are confined in all three dimensions is called a quantum dot, and the effective band gap increases as the size decreases. That is, as the size of the quantum dot decreases, its absorption and emission shift to shorter wavelengths, in other words, from the red direction to the blue direction. In addition, by controlling the composition and size of the quantum dot in combination, a wide spectrum from the infrared region to the ultraviolet region can be obtained, and by further controlling the size distribution, the color purity with a narrow half width Excellent spectrum can be obtained.
Therefore, in recent years, a quantum dot type organic EL element using quantum dots made of semiconductor nanocrystals as a light emitting material has been proposed by making use of these characteristics.

For example, Patent Document 1 discloses an electroluminescent device using a composition containing quantum dots and a non-conjugated polymer compound (claims 1 and 18). Specifically, a red quantum dot is disclosed which is composed of a CdSe core and a ZnS shell and is coated with trioctyl phosphine oxide ([0272]).
Further, Patent Document 2 describes an invention in which a chemical bond is formed between a quantum dot and a block copolymer polymer having a functional group containing sulfur to stabilize a colloid of a quantum dot-block copolymer hybrid. (Claims 1, 8 and [0008]). Specifically, the use of poly (styrene-b-cysteamine acrylamide) is disclosed as one of the block copolymers having a functional group containing sulfur.
Furthermore, Patent Document 3 describes that a light emitting layer is formed using a dispersion of semiconductor ultrafine particles in a polymer compound (claims 1 and 5). And, as the polymer compound, polyparaphenylene polymer, polyparaphenylene vinylene polymer, polythiophene polymer, polyaniline polymer, polypyrrole polymer, polycarbazole polymer, polyvinylcarbazole polymer, etc. Are illustrated ([0026]). In addition, it is disclosed that trioctyl phosphine oxide or the like is supported on the surface of the semiconductor ultrafine particles ([0025]).

Japanese Patent Application Publication No. 2013-531883 JP, 2011-195810, A JP, 2004-172102, A

Since the quantum dots themselves are made of inorganic compounds, high durability can be expected, and since sharp emission spectra that are difficult with organic substances can be obtained, their application to displays excellent in color reproducibility is expected.
However, the ligand specifically disclosed in Patent Documents 1 and 3 is trioctyl trioctyl phosphine oxide, which has hindered the injection of electrons and holes into the semiconductor nanoparticles.
Further, Patent Documents 1 to 3 do not suggest any technical idea that a polymer having a side chain having an aromatic skeleton is adsorbed to a semiconductor nanoparticle and used as a ligand. The non-conjugated polymer described in Patent Document 1 can be obtained by radical copolymerization of a vinyl compound ([0174]), and can have an aromatic skeleton such as anthracene or benzoanthracene in the side chain. There is no suggestion of a technical idea that disclosed ([0182]) has an adsorption group for semiconductor nanoparticles in the side chain.

Semiconductor nanoparticles as quantum dots are generally synthesized in the liquid phase in the presence of a ligand, and the surface is covered with the ligand and obtained in a dispersed state in the liquid phase. In addition to the control of the particle size, it is for stably dispersing the purified semiconductor nanoparticles in the liquid phase.
However, the conventional ligand is one in which an aliphatic carbon chain is bonded to an adsorptive group such as a functional group containing sulfur, and since it is insulating, it impairs the electrical properties of the quantum dot. In addition, the number of adsorption groups per one molecule is one, and there is a problem that the adsorption to semiconductor nanoparticles is weak and they are desorbed for some reason.
An object of the present invention is a dispersion of semiconductor nanoparticles which is excellent in dispersion stability, light emission quantum yield and heat resistance thereof, and can exhibit a light emission quantum yield which is substantially the same as the light emission quantum yield of the dispersion. Providing a dispersion capable of forming a semiconductor layer, and providing a semiconductor layer excellent in light emitting quantum yield and heat resistance using the dispersion, and further using the dispersion, a long lifetime and luminous efficiency An object of the present invention is to provide an electroluminescent device having a high relative luminance.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining, in order to solve the said subject, the present inventors discovered that it was important to use what has a side chain which has a conjugated structure and an adsorption group as a ligand with respect to a semiconductor nanoparticle.
That is, the present invention relates to the following [1] to [11].

[1] A semiconductor nanoparticle 2 having an average particle diameter of 50 nm or less, in which at least a part of the surface of the semiconductor nanoparticle 1 is covered with the following ligand,
The ligand has a main chain not having a conjugated structure, and a side chain bonded to the main chain,
The side chain has a conjugated structure and an adsorptive group,
Semiconductor nanoparticles 2.

[2] The semiconductor nanoparticle 1 has a core made of a first semiconductor, and a shell made of a second semiconductor which covers at least a part of the core and is different from the first semiconductor.
Semiconductor nanoparticles 2 described in the above [1].

[3] The semiconductor nanoparticle 2 according to the above [2], wherein the core and the shell are each independently composed of a II-VI semiconductor or a III-V semiconductor.

[4] The ligand has a main chain not having a conjugated structure, and a plurality of side chains linked to the main chain,
At least one of the plurality of side chains has a conjugated structure and does not have an adsorptive group,
At least one of the other side chains among the plurality of side chains has an adsorptive group and does not have a conjugated structure,
The semiconductor nanoparticle 2 according to any one of the above [1] to [3].

[5] The semiconductor nano according to the above [4], wherein the side chain having a conjugated structure and not having an adsorptive group and the side chain having an adsorptive group and not having a conjugated structure respectively form a block. Particles 2.

[6] The ligand has a main chain not having a conjugated structure, and a plurality of side chains attached to the main chain,
At least one of the side chains has a conjugated structure and an adsorptive group,
The semiconductor nanoparticle 2 according to any one of the above [1] to [3].

[7] The adsorptive group is an amino group, a hydroxyl group, a carboxyl group, a thiol group, a sulfuric acid group, a sulfonic acid group, a phosphine group, a phosphonic acid group,-(P = O) R'R '', a cyano group, -CH = The semiconductor nanoparticle 2 according to any one of the above [1] to [6], which is at least one functional group selected from the group consisting of C (CN) ₂ and —CH = C (CN) COOH .
Here, R′R ′ ′ represents an aliphatic hydrocarbon group.

[8] A dispersion liquid containing the semiconductor nanoparticle 2 according to any one of the above [1] to [7] and a liquid dispersion medium.

[9] A semiconductor layer comprising the semiconductor nanoparticle 2 according to any one of the above [1] to [7].

[10] A method for producing a laminate comprising a base material and a semiconductor layer composed of semiconductor nanoparticles 2;
The dispersion described in the above [8] is coated on a substrate, and the liquid dispersion medium is dried,
Method of manufacturing a laminate.

[11] An electroluminescent device comprising an anode, a cathode, and the semiconductor layer according to the above [9] between the anode and the cathode.

  According to the present invention, it is a dispersion of semiconductor nanoparticles which is excellent in dispersion stability, light emission quantum yield and its heat resistance, and can exhibit a light emission quantum yield which is substantially the same as the light emission quantum yield of the dispersion. A dispersion capable of forming a semiconductor layer can be provided, and the dispersion can be used to provide a semiconductor layer excellent in light emission quantum yield and heat resistance, and the dispersion can be used to extend the life. An electroluminescent element with high luminous efficiency and high relative luminance can be provided.

The semiconductor nanoparticle 1 in the present invention will be described.
As a material of the semiconductor nanoparticles, periodic table group IV elements such as carbon (C) (amorphous carbon, graphite, graphene, carbon nanotubes, diamond etc.), silicon (Si), germanium (Ge), tin (Sn) etc. Of the periodic table group V element such as phosphorus (P) (black phosphorus),
A simple substance of a periodic table group VI element such as selenium (Se) or tellurium (Te),
Tin (IV) boron nitride (BN), boron phosphide (BP), boron arsenide (BAs), aluminum nitride (AlN), aluminum phosphide (AlP), aluminum arsenide (AlAs), aluminum antimonide (AlSb), Gallium nitride (GaN), gallium phosphide (GaP), gallium arsenide (GaAs), gallium antimonide (GaSb), indium nitride (InN), indium phosphide (InP), indium arsenide (InAs), indium antimonide (InSb) Compounds of periodic table group III elements and periodic table group V elements such as
Aluminum sulfide (Al ₂ S ₃ ), aluminum selenide (Al ₂ Se ₃ ), gallium sulfide (Ga ₂ S ₃ ), gallium selenide (GaSe, Ga ₂ Se ₃ ), gallium telluride (GaTe, Ga ₂ Te ₃ ) , Periodic table group III elements such as indium oxide (In ₂ O ₃ ), indium sulfide (In ₂ S ₃ , InS), indium selenide (In ₂ Se ₃ ), indium telluride (In ₂ Te ₃ ), etc. Compounds with Group VI elements,
Zinc oxide (ZnO), zinc sulfide (ZnS), zinc selenide (ZnSe), zinc telluride (ZnTe), cadmium oxide (CdO), cadmium sulfide (CdS), cadmium selenide (CdSe), cadmium telluride (CdTe) A compound of a periodic table group II element and a periodic table group VI element such as mercury sulfide (HgS), mercury selenide (HgSe), mercury telluride (HgTe), etc.
Compound of periodic table group I element with periodic table group VI element such as copper (I) oxide (Cu ₂ O),
Periodic group I elements such as copper (I) chloride (CuCl), copper (I) bromide (CuBr), copper iodide (I) (CuI), silver chloride (AgCl), silver bromide (AgBr) and the like Examples thereof include compounds with Group VII elements of the periodic table, and two or more of these may be used in combination, as necessary.
In addition, a compound of a periodic table group II element and a periodic table group VI element is referred to as a II-VI group semiconductor, or a compound of a periodic table group III element and a periodic table group V element is a group III-V semiconductor It is called.

These materials may contain elements other than the constituent elements.
For example, in the case of group III-V as an example, alloy systems such as INGaP and INGaN may be used. In addition, semiconductor nanoparticles doped with rare earth elements or transition metal elements are also used in the above-mentioned materials. For example, ZnS: Mn, ZnS: Tb, ZnS: Ce, LaPO ₄ : Ce, etc. may be mentioned.
Among these, silicon (Si), germanium (Ge), gallium nitride (GaN), gallium phosphide (GaP), gallium arsenide (GaAs), indium nitride (InN), indium phosphide (InP), indium arsenide (InAs), gallium selenide (GaSe, Ga2Se3), indium sulfide _{(In 2 S 3, InS)} , zinc oxide (ZnO), zinc sulfide (ZnS), zinc selenide (ZnSe), zinc telluride (ZnTe), cadmium oxide (CdO Alloy systems such as cadmium sulfide (CdS), cadmium selenide (CdSe), cadmium telluride (CdTe), InGaP, InGaN, etc. are preferably used, and in particular, indium phosphide (InP), cadmium selenide (CdSe), Zinc sulfide (ZnS), zinc selenide (ZnSe) in particular Used Mashiku.

Furthermore, a perovskite crystal can be particularly preferably used as the semiconductor nanoparticle 1. The perovskite crystal referred to in the present invention has a composition represented by the following formula and has a three-dimensional crystal structure.
Composition formula: AQX ₃
In the above formula, A is a monovalent cation of an amine compound which is at least one selected from methyl ammonium (CH ₃ NH ₂ ) and formamidinium (NH ₂ CHNH), or rubidium (Rb) A metallic element which is a monovalent cation of at least one alkali metal element selected from cesium (Ce) and franch (Fr), and Q is at least one selected from lead (Pb) and tin (Sn) And X is a monovalent anion of at least one halogen element selected from iodine (I), bromine (Br), and chlorine (Cl).

  The semiconductor nanoparticle 1 preferably has a core-shell structure. The core-shell type semiconductor nanoparticle 1 is one in which the core is covered with a material comprising a component different from the material forming the core. By making the shell a semiconductor with a large band gap, excitons (electron-hole pairs) generated by light excitation are confined in the core. As a result, the probability of non-radiative transition on the particle surface is reduced, and the quantum yield of light emission and the stability of the fluorescence characteristics are improved. Also, there may be multiple layers of shells. Furthermore, the boundaries between the core and the shell and between one shell and the other shell may be defined as well as in a gradually joined gradient structure with a concentration gradient.

In the semiconductor nanoparticle 2 of the present invention, at least a part of the surface of the semiconductor nanoparticle 1 is covered with a ligand, and the average particle diameter is 100 nm or less.
As a method of covering at least a part of the surface of the semiconductor nanoparticle 1 with a ligand, for example,
A method of synthesizing a semiconductor nanoparticle 1 in the presence of a ligand and producing a semiconductor nanoparticle 2 on which the ligand is adsorbed,
A method of obtaining semiconductor nanoparticles 2 in which the ligand is adsorbed on the surface of the semiconductor nanoparticle 1 by stirring the semiconductor nanoparticle 1 and the ligand in a liquid phase;
After substantially removing the liquid phase (dispersion medium) from the dispersion containing the semiconductor nanoparticles 1 by centrifugal sedimentation etc., the ligand was adsorbed when the semiconductor nanoparticles 1 were redispersed in the liquid phase (dispersion medium) containing the ligand The method of producing the semiconductive nanoparticle 2 etc. can be mentioned as an example.

The ligand in the present invention is described.
The ligand in the present invention has a main chain not having a conjugated structure and a side chain bonded to the main chain, and the side chain has a conjugated structure and an adsorptive group. Examples of combinations of the conjugated structure and the adsorptive group include the following cases (1) to (2).
(1) having a plurality of side chains attached to the main chain,
At least one of the plurality of side chains has a conjugated structure and does not have an adsorptive group,
In the case where the other side chain among the plurality of side chains has an adsorptive group and does not have a conjugated structure.
In this case, the former side chain (hereinafter sometimes abbreviated as a side chain having a conjugated structure) and the latter side chain (hereinafter sometimes abbreviated as a side chain having an adsorptive group) are opposite to the main chain , Can form a block.
(2) having a plurality of side chains attached to the main chain,
In the case where at least one of the side chains has a conjugated structure and an adsorptive group.

  The ligand in the present invention is considered to be polyacrylate, polymethacrylate, polyvinylate, polyamide, polyurethane, polycarbonate, polyimide, cellulose or a combination thereof. In particular, although there is no limitation, polyacrylate or vinyl resin or a combination thereof is preferable. In other words, the main chain of the ligand is preferably formed by polymerization of a vinyl group, an allyl group, an acryl group, a methacryl group, an acrylimide group, a methacrylimide group and the like.

  The conjugated structure in the side chain of the ligand is described. The conjugated structure includes a substituted or unsubstituted aromatic hydrocarbon structure or a substituted or unsubstituted aromatic heterocycle.

  Here, as a substituted or unsubstituted aromatic hydrocarbon structure, benzene, naphthalene, anthracene, naphthacene, bentacene, fluorene, phenanthrene, pyrene, perylene, perylene, biphenyl, p-terphenyl, m-terphenyl, and o- Terphenyl etc. are mentioned.

  Here, as the substituted or unsubstituted aromatic heterocyclic structure, pyrrole, furan, thiophene, imidazole, pyrazole, oxazole, isoxazole, thiazole, isothiazole, pyridine, pyrimidine, pyridazine, pyrazine, 1,2,3- Triazine, 1,3,5-triazine, quinoline, isoquinoline, quinazoline, phthalazine, pterazine, coumarin, chromone, chromone, indole, benzimidazole, benzofuran, purine, acridine, phenoxazine, phenothiazine, porphyrin, phthalocyanine and the like. Here, porphyrin and phthalocyanine may be accompanied by a central metal.

  Here, as the substituted or unsubstituted aromatic hydrocarbon structure and the substituted or unsubstituted aromatic heterocyclic ring structure, a structure of condensation or linking of at least two or more rings is preferable. This is because in a single ring, the interaction between π electrons is small and the electrical conductivity is inferior.

The adsorbing group in the side chain of the ligand is described.
As an adsorption group, an amino group, a hydroxyl group, a carboxyl group, a thiol group, a sulfuric acid group, a sulfonic acid group, a phosphine group, a phosphonic acid group,-(P = O) R'R ", a cyano group, -CH = C ( CN) ₂ , and -CH = C (CN) COOH, and the like.
Here, R′R ′ ′ represents an aliphatic hydrocarbon group. Moreover, as an aliphatic hydrocarbon group, the below-mentioned thing is mentioned.

  A preferred example of the ligand of the present invention is represented by the following general formula (1).

(In the general formula (1),
R ¹ represents a hydrogen atom or a methyl group,
L ¹ represents a direct bond or-(C = O).
L ² is, ^{L 1} is - (C = O) - For a direct bond, -NR ⁷ -, or represents -O-, ^{L 1} is, if it represents a direct bond, the ^{L 2} is a direct bond Represent.
L ³ is a structure comprising a direct bond, or a substituted or unsubstituted divalent aliphatic hydrocarbon group, -O-, -NR ⁸ -,-(C = O)-, and a combination thereof If it is not a direct bond, a divalent aliphatic hydrocarbon group is always bonded to L ² first.
Here, R ⁷ and R ⁸ each independently represent a hydrogen atom or an aliphatic hydrocarbon group.
R ² is a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted aromatic heterocyclic group.

R ³ represents a hydrogen atom or a methyl group,
L ⁴ represents a direct bond or-(C = O).
L ⁵ represents, ^{L 4} is - (C = O) - For a direct bond, -NR ⁹ -, or represents -O-, ^{if L 4} represents a direct bond represents the ^{L 5} also direct bond.
L ⁶ is a structure comprising a direct bond, or a substituted or unsubstituted divalent aliphatic hydrocarbon group, —O—, —NR ¹⁰ —, — (COO) —, and a combination thereof If it is not a direct bond, a divalent aliphatic hydrocarbon group is always bonded to L ⁵ first.
Here, R ⁹ and R ¹⁰ each independently represent a hydrogen atom or an aliphatic hydrocarbon group.
R ⁴ is a substituted or unsubstituted aliphatic hydrocarbon group or a substituted or unsubstituted aliphatic heterocyclic group.
However, at least one of L ⁶ and R ⁴ has at least one adsorptive group. However, it specifically includes the case where L ⁴ is —NH—, L ⁵ and L ⁶ are a direct bond, and R ⁴ is a hydrogen atom, and in this case, it has an adsorptive group as a substituent. You do not have to.

R ⁵ represents a hydrogen atom or a methyl group,
L ⁷ represents a direct bond or-(C = O).
L ⁸ is, ^{L 7} is - (C = O) - For a direct bond, ^{-NR 11} -, or represents -O-, ^{if L 7} represents a direct bond represents a bond directly be ^{L 8.}
L ⁹ is a structure comprising a direct bond, or a substituted or unsubstituted divalent aliphatic hydrocarbon group, -O-, -NR ¹² -,-(C = O)-, and a combination thereof If it is not a direct bond, a divalent aliphatic hydrocarbon group is always bonded to L ⁸ first.
Here, R ¹¹ and R ¹² each independently represent a hydrogen atom or an aliphatic hydrocarbon group.
Furthermore, R ⁶ is a substituted or unsubstituted aliphatic hydrocarbon group or a substituted or unsubstituted aliphatic heterocyclic group.
However, L ⁹ and R ¹⁶ do not have an adsorptive group.

  x, y and z represent quantity ratios, and x + y + z = 100, which are respectively selected so as to satisfy 100 ≧ x ≧ 50, 50> y ≧ 0.1, and 50> Z00. )

  Although the specific example regarding General formula (1) is given to the following, these do not restrict | limit this invention at all.

L ^3, examples of the divalent aliphatic hydrocarbon group for _{^{L 6, L 9, -CH 2}} -, - (CH 2) 2 -, - (CH 2) 3 -, - (CH 2) 4 -, - _{(CH 2) 5} -, and, - _{(CH 2) 6} -, and the like.

The aromatic hydrocarbon group for R ² includes a single ring, a condensed ring and a ring-aggregated hydrocarbon group.
Among the above aromatic hydrocarbon groups, those of monocyclic type include phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, 2,4-xylyl group, p-cumenyl group, mesityl group, etc. And a monocyclic aromatic hydrocarbon group having 6 to 18 carbon atoms.

  Further, among the above aromatic hydrocarbon groups, as a condensed ring type, 1-naphthyl group, 2-naphthyl group, 1-anthryl group, 2-anthryl group, 5-anthryl group, 1-phenanthryl group, 9 -A fused ring hydrocarbon group having 10 to 18 carbon atoms such as phenanthryl group, 1-acenaphthyl group, 2-azulenyl group, 1-pyrenyl group, 2-pyrenyl group, 4-pyrenyl group, 2-triphenylyl group and the like can be mentioned.

  Further, among the above-mentioned aromatic hydrocarbon groups, as a ring assembly type, o-biphenylyl group, m-biphenylyl group, p-biphenylyl group, 9,9H-fluorin-2-yl group, 9H-fluorine A C12-18 ring assembly hydrocarbon group, such as a -9-yl group, can be mentioned.

Examples of the aromatic heterocyclic group for R ² include triazolyl group, 3-oxadiazolyl group, 2-furanyl group, 3-furanyl group, 2-furyl group, 3-furyl group, 2-thienyl group, 3-thienyl group, 1 -Pyrrolyl group, 2-pyrrolyl group, 3-pyrrolyl group, 2-pyridyl group, 3-pyridyl group, 4-pyridyl group, 2-pyrazyl group, 2-oxazolyl group, 3-isoxazolyl group, 2-thiazolyl group, 3-isothiazolyl group, 2-imidazolyl group, 3-pyrazolyl group, 2-quinolyl group, 3-quinolyl group, 4-quinolyl group, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group, 8-quinolyl group, 1-isoquinolyl group, 2-quinoxalinyl group, 2-benzofuryl group, 2-benzothienyl group, N-indolyl group, N-carbazolyl group, N-acridinyl group, 2- Examples thereof include C2-C18 aromatic heterocyclic groups such as thiophenyl group, 3-thiophenyl group, bipyridyl group and phenanthrolyl group.

The aliphatic hydrocarbon group as R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ and R ¹² refers to an aliphatic hydrocarbon group having 1 to 18 carbon atoms, and as such, an alkyl group, And alkenyl groups, alkynyl groups and cycloalkyl groups.

  Among the above aliphatic hydrocarbon groups having 1 to 18 carbon atoms, as an alkyl group, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group And alkyl groups having 1 to 18 carbon atoms such as isopentyl group, hexyl group, heptyl group, octyl group, decyl group, dodecyl group, pentadecyl group and octadecyl group.

  Among the above aliphatic hydrocarbon groups having 1 to 18 carbon atoms, as an alkenyl group, a vinyl group, 1-propenyl group, 2-propenyl group, isopropenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group And alkenyl groups having 2 to 18 carbon atoms such as 1-octenyl group, 1-decenyl group and 1-octadecenyl group.

  Among the above aliphatic hydrocarbon groups having 1 to 18 carbon atoms, the alkynyl group is preferably an ethynyl group, 1-propynyl group, 2-propynyl group, 1-butynyl group, 2-butynyl group, 3-butynyl group, 1- C2-C18 alkynyl groups, such as an octynyl group, 1-decynyl group, and 1-octadecynyl group, are mentioned.

  Among the above aliphatic hydrocarbon groups having 1 to 18 carbon atoms, as a cycloalkyl group, a cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclooctadecyl group, 1-adamantyl group And C2-C18 cycloalkyl groups such as 2-adamantyl group.

Examples of the aliphatic heterocyclic group for R ⁴ and R ⁶ include aliphatic heterocyclic groups having 3 to 18 carbon atoms such as 2-pyrazolino group, piperidino group, morpholino group, and 2-morpholinyl group.
As an adsorptive group in R ⁴ and R ⁶ , amino group, hydroxyl group, carboxyl group, thiol group, sulfuric acid group, sulfonic acid group, phosphinic acid group, phosphonic acid group,-(P = O) R′R ′ ′, cyano Groups, -CH = C (CN) ₂ , and -CH = C (CN) COOH, and the like.
Here, R′R ′ ′ represents an aliphatic hydrocarbon group. Moreover, as an aliphatic hydrocarbon group, the above-mentioned thing is mentioned.

When the adsorptive group is an acidic functional group, hydrogen ions may be exchanged with other monovalent cations, and as monovalent cations mentioned here, Li ⁺ , Na ⁺ , and K ⁺ , Etc.

Moreover, in the state which the adsorption group is adsorb | sucking to a semiconductor nanoparticle, the case where the adsorption group is ionizing is anticipated, and this invention also includes the concept. For ^{example, -OH → -O -, -CООH →} -CОО -, -NH 2 → -NH 3 +, -SH → -S -, -SO 3 H → -SO 3 -, -O-SO 3 H → - _{^{O-SO 3 -, -PO 4}} H 2 → -PO 4 2-, and the like.

As a substituent which L ³ and R ² may independently have, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aliphatic heterocyclic group, a substituted or unsubstituted aromatic Group hydrocarbon groups, substituted unsubstituted aromatic heterocyclic groups, halogen elements, and adsorptive groups.
Examples of the halogen element include fluorine atom, chlorine atom, bromine atom and iodine atom.
As examples other than the halogen element, the above-mentioned ones can be mentioned.

As a substituent which L ⁶ and R ⁴ may independently have, a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aliphatic heterocyclic group, a halogen element, and an adsorption Groups, and examples of these include those mentioned above. However, at least one of L ⁶ and R ⁴ has at least one adsorptive group.

Examples of the substituent which L ⁹ and R ⁶ may independently have include a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aliphatic heterocyclic group, and a halogen element. Examples of these include those mentioned above. However, L ⁹ and R ⁶ do not have an adsorptive group.

In addition, the case where L ⁴ is —NH—, L ⁵ and L ⁶ are a direct bond, and R ⁴ is a hydrogen atom is specifically included, and in this case, it has an adsorptive group as a substituent. Although it may not be necessary, an amino group contained in the side chain is used as an adsorptive group.

  The polymer of the general formula (1) may be either a random copolymer or a block copolymer, and the exemplified compounds described below may contain both concepts.

  In addition, each of the repeating units in the general formula (1) may be used in combination of two or more types within the range according to the description of the general formula (1). In that case, x, y, z are handled by the total value.

  In the general formula (1), when two or more direct bonds are continuous, they are collectively treated as one direct bond.

  As a method of synthesizing the ligand represented by the general formula (1) in the present invention, for example, by polymerizing a monomer having a vinyl group, an allyl group, an acryl group, a methacryl group, an acrylimide group, a methacrylimide group and the like. You can get it.

  For example, solution polymerization, which is a method in which various monomers serving as raw materials and a catalyst are introduced into a solvent which hardly reacts with the monomer and the catalyst, and polymerization is carried out in a solution may be mentioned as a synthesis method.

The method for producing the block copolymer is not particularly limited. The block polymer can be obtained, for example, by sequentially polymerizing monomers by block polymerization using a living radical polymerization method or the like. Living radical polymerization is a polymerization method that enables precise control of molecular structure while maintaining the simplicity and versatility of radical polymerization. In living radical polymerization methods, methods using transition metal catalysts (ATRP), methods using sulfur-based reversible chain transfer agents (RAFT), methods using organic tellurium compounds, depending on the method of stabilizing the polymerization growth terminal There are methods such as (TERP). Among these methods, it is preferable to use a method (TERP) using an organic tellurium compound from the viewpoint of the variety of usable monomers and the control of molecular weight in the polymer region. The RAFT method is detailed in the Australian Journal of Chemistry, 2009, 62, 1402-1472.
Moreover, as for the TERP method, for example, the method described in WO 2015/072333 can be mentioned.

In addition, the thiol group, which is an adsorptive group, has strong reactivity to vinyl, allyl, acryl, methacryl, acrylimido, methacrylimido and the like. Therefore, after the polymerization is carried out, the target ligand can be obtained by using a removal or exchange reaction of a protective group.
Such a method is described in detail, for example, in JP 2011-195810, Macromolecules, 2102, 45 (2), 821-827, Polymer International, 63 (5), 2014, 887, 893 and the like.

  Below, the ligand represented by General formula (1) of this invention is shown.

  The semiconductor nanoparticle 2 of the present invention may be covered by the conventionally known ligands listed below in addition to the above-mentioned ligands.

As conventionally known ligands, thiols such as methanethiol, ethanethiol, propanethiol, butanethiol, pentanethiol, hexanethiol, octanethiol, dodecanethiol, hexadecanethiol, octadecanethiol, benzylthiol, etc .; mercaptomethanol, mercaptoethanol, Mercapto spacer alcohols such as mercaptopropanol, mercaptobutanol, mercaptopentanol and mercaptohexanol; Mercapto spacer carboxylic acids such as mercaptoacetic acid, mercaptopropionic acid, mercaptobutanoic acid, mercaptohexanoic acid, and mercaptoheptane; Mercaptomethanesulfonic acid, mercaptoethane Sulfonic acid, mercaptopropane sulfonic acid, mercapto benzene sulfone Mercapto spacer sulfonic acids such as mercaptomethanamine, mercaptoethanamine, mercaptopropanamine, mercaptobutaneamine, mercaptopentanamine, mercaptohexanamine, mercaptopyridine etc. mercapto spacer amines; mercapto methyl thiol, mercapto ethyl thiol, mercapto propyl Mercapto spacer thiols such as thiol, mercapto butyl thiol and mercapto pentyl thiol; methanamine, ethane amine, propane amine, propane amine, butane amine, pentane amine, hexane amine, octano amine, dodecane amine, hexadecyl amine, octadecyl amine, dimethyl amine, diethyl amine, diamine Amines such as propylamine; aminomethanol, aminoethanol Amino spacer alcohols such as aminopropanol, aminobutanol, aminopentanol and aminohexanol; amino spacer carboxylic acids such as aminoacetic acid, aminopropionic acid, aminobutanoic acid, aminohexanoic acid and aminoheptanoic acid; aminomethanesulfonic acid, amino Amino spacer sulfonic acids such as ethanesulfonic acid, aminopropanesulfonic acid, aminobenzenesulfonic acid; aminomethanamine, aminoethanamine, aminopropanamine, aminobutylamine, aminopentylamine, aminohexylamine, aminobenzeneamine, aminopyridine etc. Amino spacer amines or diamines; methane acid (formic acid), ethanoic acid, propanoic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, dode Carboxylic acids such as kanamic acid, hexadecanoic acid, octadecanoic acid, oleic acid, benzoic acid, etc .; carboxylic acid methanol (ie, carboxylic acid group separated from alcohol group by —CH ₂ — group or 2-hydroxyethanoic acid), Carboxylic acid spacer alcohols such as ethanol (that is, 3-hydroxypropanoic acid), carboxylic acid propanol, carboxylic acid butanol, carboxylic acid pentanol, carboxylic acid hexanol; carboxylic acid methanesulfonic acid, carboxylic acid ethanesulfonic acid, carboxylic acid Carboxylic acid spacer sulfonic acids such as propane sulfonic acid and carboxylic acid benzene sulfonic acid; carboxylic acid methane carboxylic acid (ie propane diacid) carboxylic acid ethane carboxylic acid (ie butane di acid) carboxylic acid pro Carboxylic acid, carboxylic acid propanecarboxylic acid, carboxylic acid benzenecarboxylic acid, such as carboxylic acid benzene carboxylic acid; methyl phosphine, ethyl phosphine, propyl phosphine, butyl phosphine, phosphine such as pentyl phosphine; phosphine methanol, phosphine ethanol, phosphine propanol, Phosphine spacer alcohols such as phosphine butanol, phosphine pentanol, phosphine hexanol; Phosphine spacer sulfonic acids such as phosphine methanesulfonic acid, phosphine ethane sulfonic acid, phosphine propane sulfonic acid, phosphine benzene sulfonic acid, etc. phosphine methane carboxylic acid, phosphine ethane carboxylic acid Acid, phosphine propane carboxylic acid, phosphine benzene carboxylic acid, etc. Phosphine spacer carboxylic acids; Phosphine spacer amines such as phosphine methanamine, phosphine ethanamine, phosphine propanamine, phosphine benzene amine; phosphine oxides such as methyl phosphine oxide, ethyl phosphine oxide, propyl phosphine oxide, butyl phosphine oxide, etc. phosphine oxide Phosphine oxide alcohols such as methanol, phosphine oxide ethanol, phosphine oxide propanol, phosphine oxide butanol, phosphine oxide pentanol, phosphine oxide hexanol; phosphine oxide methanesulfonic acid, phosphine oxide ethane sulfonic acid, phosphine oxide propane sulfonic acid, phosphine oxide benzene Sulfonic acid etc Phosphine oxide spacer sulfonic acids; Phosphine oxide spacer carboxylic acids such as phosphine oxide methanecarboxylic acid, phosphine oxide ethane carboxylic acid, phosphine oxide propane carboxylic acid, phosphine oxide benzene carboxylic acid, etc .; and phosphine oxide methanamine, phosphine oxide ethanamine, phosphine And phosphine oxide spacer amines such as oxide propanamine and phosphine oxide benzenamine.

  The average particle size of the semiconductor nanoparticles 1 and 2 is 100 nm or less, preferably 1 to 50 nm, and more preferably 1 to 15 nm.

  The average particle size said here refers to the value which observed the semiconductor nanoparticle 1 or the semiconductor nanoparticle 2 with a transmission electron microscope, measured the size of 30 pieces at random, and adopted the average value. Under the present circumstances, in the semiconductor nanoparticle 2, after specifying a semiconductor material part by using the scanning transmission electron microscope attached to energy dispersive X-ray analysis, the difference of the electron density in a transmission electron microscope image shows the below-mentioned. The particle diameter is measured using the fact that the semiconductor nanoparticle 1 portion is imaged dark relative to the ligand.

  The shape of the quantum dots as the shape of the semiconductor nanoparticles 1 and 2 is not limited to the spherical shape, and may be a rod shape, a disk shape, or any other shape.

  Next, a dispersion containing the semiconductor nanoparticles 2 of the present invention and a liquid dispersion medium (hereinafter, the dispersion of the present invention) will be described.

  The dispersion liquid of the present invention is excellent in resistance and dispersion stability of the semiconductor nanoparticles 2 by covering at least a part of the semiconductor nanoparticles 2 with the ligand of the present invention.

  Although the reason is not clear, since the ligand of the present invention has a plurality of adsorbing groups in the polymer, it is difficult to be released by multipoint adsorption to the semiconductor nanoparticles, and hence the ligand is a semiconductor compared to conventionally known ligands. It is assumed that the nanoparticles are strongly and densely coated. Therefore, it is considered to exhibit excellent properties in the effect of maintaining dispersion and the effect of protecting semiconductor nanoparticles.

  As the organic liquid dispersion medium, so-called various organic solvents can be applied and are not particularly limited. For example, aromatic hydrocarbons such as toluene, o-xylene, m-xylene, p-xylene, methycylene, cyclohexylbenzene and tetralin; halogenated aromatic hydrocarbons such as chlorobenzene, dichlorobenzene and trichlorobenzene; Aromatic ethers such as benzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole; phenyl acetate, Aromatic esters such as phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, n-butyl benzoate; alicyclic ketones such as cyclohexanone and cyclooctanone; aliphatic ketones such as methyl ethyl ketone and dibutyl ketone; Me Alicyclic alcohols such as ethyl ethyl ketone, cyclohexanol and cyclooctanol; aliphatic alcohols such as butanol and hexanol; aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol 1-monomethyl ether acetate (PGMEA) Aliphatic esters such as ethyl acetate, n-butyl acetate, ethyl lactate and n-butyl lactate; n-hexane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, Aliphatic hydrocarbons such as n-heptane, n-decane, 2,2,4-trimethylpentane, cyclohexane, methylcyclohexane, mineral spirits, and the like.

Among these, aromatic hydrocarbons such as toluene, xylene, methycylene, cyclohexylbenzene and tetralin are preferable in that they have low water solubility and do not easily deteriorate.
Since many materials that are significantly degraded by moisture are used in the electroluminescent element for the cathode etc., the liquid dispersion medium used is also such that moisture is unlikely to remain in the film after drying from the point of view of element characteristics. It is preferable to select one that is rich in hydrophobicity.

  These liquid dispersion media may be used alone or in combination of two or more. The usable liquid dispersion medium is not limited to these.

  The dispersion of the present invention is mainly used to form a light emitting layer, but may be used in other layers such as a hole transport layer.

  The dispersion liquid of the present invention may contain other known light emitting materials described later as long as the object of the present invention is not impaired.

  Known additives may be added to the dispersion of the present invention as required. Examples of known additives include, but are not limited to, antifoaming agents, leveling agents, and thickeners.

  The dispersion of the present invention can be prepared by known wet film forming methods such as coating method, ink jet method, dip coating method, die coating method, spray coating method, spin coating method, roll coater method, wet coating method, screen printing method, Film formation can be performed by flexographic printing, screen printing, LB method or the like. In addition, JP 2002-534782 and S.E. T. Lee, et al. , Proceedings of SID'02, p. The film may be formed by LITI (Laser Induced Thermal Imaging) method described in 784 (2002).

The semiconductor layer consisting of the semiconductor nanoparticle 2 of the present invention (hereinafter, the semiconductor layer of the present invention) will be described.
The semiconductor layer of the present invention contains at least one kind of the semiconductor particles 2 of the present invention, may contain two or more kinds at the same time, and may further contain various electroluminescent element materials described above.

The semiconductor layer of the present invention can be formed by applying the dispersion of the present invention on a substrate and drying the liquid dispersion medium.
The semiconductor layer of the present invention is excellent in the resistance of the semiconductor nanoparticle 2 by covering at least a part of the semiconductor nanoparticle 2 with the specific ligand described above, and maintaining its light emitting property over a long period of time Can. Furthermore, it is known that, in the case of powders and films obtained by drying the dispersion liquid, the emission quantum yield is reduced, as compared with the emission quantum yield exhibited in the dispersion liquid, although general semiconductor nanoparticles are used. The semiconductor layer can maintain the light emission quantum yield equivalent to that of the dispersion.

Next, as a specific application of the semiconductor nanoparticle 2 of the present invention, an electroluminescent device using the semiconductor nanoparticle 2 will be described.
The electroluminescent device of the present invention comprises a semiconductor layer composed of the semiconductor nanoparticle 2 of the present invention between an anode and a cathode, and the semiconductor layer composed of the semiconductor nanoparticle 2 is a light emitting layer.
The light emitting layer may be in direct contact with the anode and the cathode (a single-layer type electroluminescent device).
Alternatively, in addition to the light emitting layer, it facilitates the injection of holes and electrons into the light emitting layer between the anode and the cathode, and facilitates the recombination of holes and electrons in the light emitting layer. A hole injection layer, a hole transport layer, a hole blocking layer, an electron injection layer and the like may be stacked for the purpose of forming a so-called multilayer electroluminescent device.
Furthermore, an interlayer which is adjacent to the light emitting layer between the light emitting layer and the anode and has a function of separating the light emitting layer from the anode or the light emitting layer and the hole injection layer or the hole transport layer It is also possible to insert layers.

  Accordingly, among the electroluminescent devices of the present invention, typical device configurations of multilayer electroluminescent devices are (1) anode / hole injection layer / light emitting layer / cathode, (2) anode / hole injection layer / Hole transport layer / luminescent layer / cathode, (3) anode / hole injection layer / luminescent layer / electron injection layer / cathode, (4) anode / hole injection layer / hole transport layer / luminescent layer / electron injection layer / Cathode, (5) anode / hole injection layer / light emitting layer / hole blocking layer / electron injection layer / cathode, (6) anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / Electron injection layer / cathode, (7) anode / light emitting layer / hole blocking layer / electron injection layer / cathode, (8) anode / light emitting layer / electron injection layer / cathode (9) anode / hole injection layer / hole Transport layer / interlayer layer / light emitting layer / cathode, (10) anode / hole injection layer / interlayer / light emitting layer / electron injection layer / cathode, (11) anode / positive Injection layer / hole transport layer / interlayer layer / light emitting layer / electron injection layer / cathode, an element formed by laminating a multilayer structure etc. can be considered.

  Each organic layer mentioned above may be formed by layer composition of two or more layers, respectively, and several layers may be repeatedly laminated. As such an example, in recent years, for the purpose of improving the light extraction efficiency, a device configuration called “multi-photon emission” has been proposed in which some layers of the above-described multi-layered electroluminescence are multilayered. This corresponds to, for example, the charge generation layer and the light emission unit in an electroluminescent device comprising glass substrate / anode / hole transport layer / electron transport light emission layer / electron injection layer / charge generation layer / light emission unit / cathode There is a method of laminating a plurality of portions.

  Although the semiconductor layer which consists of the semiconductor nanoparticle 2 of this invention may be used for any layer mentioned above, it can be used suitably especially for a light emitting layer. Moreover, the semiconductor layer which consists of the semiconductor nanoparticle 2 of this invention may contain the other compound and the semiconductor nanoparticle.

For the hole injection layer, a hole injection material is used which exhibits an excellent hole injection effect on the light emitting layer and can form a hole injection layer excellent in adhesion to the anode interface and thin film formation. In addition, when such a material is laminated in multiple layers, and a material with a high hole injection effect and a material with a high hole transport effect are laminated, the materials used for each are called a hole injection material and a hole transport material. Sometimes. The material for an organic EL device of the present invention can be suitably used as either a hole injecting material or a hole transporting material. These hole injecting materials and hole transporting materials are required to have a high hole mobility and a small ionization energy of usually 5.5 eV or less. As such a hole injection layer, a material which transports holes to the light emitting layer with lower electric field strength is preferable, and further, the hole mobility is at least at the time of electric field application of 10 ⁴ to 10 ⁶ V / cm, for example. What is 10 ^<-6 > cm ^{< 2} > / V * second is preferable. Other hole injecting materials and hole transporting materials that can be used by mixing with the material for an organic EL device of the present invention are not particularly limited as long as they have the above-mentioned preferable properties, and In the transport material, any one can be selected and used from those commonly used as a charge transport material of holes and known materials used in a hole injection layer of an organic EL device.

  Specific examples of such hole injecting materials and hole transporting materials include triazole derivatives (see, eg, US Pat. No. 3,112,197) and oxadiazole derivatives (US Pat. No. 3,189,447). No. 3, etc., imidazole derivatives (see Japanese Patent Publication No. 37-16096 etc.), polyarylalkane derivatives (US Pat. Nos. 3,615,402 and 3,820,989) No. 3,542,544, JP-B-45-555, JP-A-51-10983, JP-A-51-93224, JP-A-55-17105, JP-A-56-4148, JP-A-55- 108667, 55-156953, 56-36656, etc.), pyrazoline derivatives and pyrazolone derivatives (US Pat. No. 3,180, No. 29, No. 4, 278, 746, JP-A No. 55-88064, No. 55-88065, No. 49-105537, No. 55-51086, and No. 56-80051. Nos. 56-88141, 57-45545, 54-112637, 55-74546 and the like), phenylenediamine derivatives (US Pat. No. 3,615,404, and the like). JP-B-51-10105, JP-A-46-3712, JP-A-47-25336, JP-A-54-53435, JP-A-54-110536, JP-A-54-119925, etc., arylamines Derivatives (US Pat. Nos. 3,567,450, 3,180,703, 3,240,597, and 3) No. 658,520, No. 4,232,103, No. 4,175,961, No. 4,012,376, Japanese Patent Publication No. 49-35702, No. 39 See, for example, JP-27577, JP-A-55-144250, JP-A-56-119132, JP-A-56-22437, West German Patent No. 1,110,518, etc., amino-substituted chalcone derivatives (US Patent No. 3,526,501), oxazole derivatives (as disclosed in US Pat. No. 3,257,203), styrylanthracene derivatives (see JP-A-56-46234), Fluorinone derivatives (see JP-A-54-110837 etc.), hydrazone derivatives (US Pat. No. 3,717,462, JP-A-54-59143), 55-52063, 55-52064, 55-46760, 55-85495, 57-11350, 57-148749, JP-A 2-311591, etc. See stilbene derivatives (JP 61-210363, JP 61-228451, JP 61-14642, JP 61-72255, JP 62-47646, JP 62-36674) 62-10652, 62-30255, 60-93455, 60-94462, 60-174749, 60-175052, etc., silazane derivatives (US Patent No. 4,950,950), polysilane system (Japanese Patent Application Laid-Open No. 2-204996), aniline type copolymerization (JP-A-2-282263), an electroconductive oligomer (particularly a thiophene oligomer) disclosed in JP-A-1-211399 and the like.

  As the hole injecting material and the hole transporting material, those described above can be used, but porphyrin compounds (JP-A-63-2956965), aromatic tertiary amine compounds and styrylamine compounds (US Pat. U.S. Pat. No. 4,127,412, JP-A-53-27033, JP-A-54-58445, JP-A-54-149634, JP-A-54-64299, JP-A-55-79450, and JP-A-55-144250. Nos. 56-119132, 61-295558, 61-98353 and 63-295695) can also be used. For example, 4,4′-bis (N- (1-naphthyl) -N-phenylamino) biphenyl having two fused aromatic rings in the molecule described in US Pat. No. 5,061,569, etc. And 4,4 ′, 4 ′ ′-tris (N- (3-methylphenyl) -N-phenyl in which three triphenylamine units are linked in a star-burst form as described in JP-A-4-308688. (Amino) triphenylamine etc. Moreover, as a hole injection material, phthalocyanine derivatives such as copper phthalocyanine and hydrogen phthalocyanine can also be mentioned Furthermore, aromatic dimethylidene compounds, p-type Si, p-type SiC etc. Inorganic compounds of the above can also be used as hole injecting materials and hole transporting materials.

Furthermore, as materials that can be used for the hole injection layer, molybdenum oxide (MnO _x ), vanadium oxide (VO _x ), ruthenium oxide (RuO _x ), copper oxide (CuO _x ), tungsten oxide (WO _x ), iridium oxide Also included are inorganic oxides such as (IrO _x ) and their dopants.

  Specific examples of the aromatic tertiary amine derivative include, for example, N, N′-diphenyl-N, N ′-(3-methylphenyl) -1,1′-biphenyl-4,4′-diamine, N, N , N ', N'-(4-methylphenyl) -1,1'-phenyl-4,4'-diamine, N, N, N ', N'-(4-methylphenyl) -1,1'- Biphenyl-4,4'-diamine, N, N'-diphenyl-N, N'-dinaphthyl-1,1'-biphenyl-4,4'-diamine, N, N '-(methylphenyl) -N, N '-(4-n-Butylphenyl) -phenanthrene-9,10-diamine, N, N-bis (4-di-4-tolylaminophenyl) -4-phenyl-cyclohexane, N, N'-bis (4) '-Diphenylamino-4-biphenylyl) -N, N'-diphenyl Indidine, N, N'-bis (4'-diphenylamino-4-phenyl) -N, N'-diphenylbenzidine, N, N'-bis (4'-diphenylamino-4-phenyl) -N, N ' -Di (1-naphthyl) benzidine, N, N'-bis (4'-phenyl (1-naphthyl) amino-4-phenyl) -N, N'-diphenylbenzidine, N, N'-bis (4'-) Phenyl (1-naphthyl) amino-4-phenyl) -N, N'-di (1-naphthyl) benzidine and the like can be mentioned, and these can be used as both the hole injecting material and the hole transporting material.

Particularly preferable examples of the hole injection material are shown in Table 2.

Moreover, as a positive hole transport material which can be used with the semiconductor nanoparticle 2 of this invention, the compound shown in following Table 3 is also mentioned.

  In order to form the hole injection layer described above, the above-mentioned compound is thinned by a known method such as, for example, a vacuum evaporation method, a spin coating method, a casting method, or an LB method. The thickness of the hole injection layer is not particularly limited, but is usually 5 nm to 5 μm.

  Examples of materials used for the interlayer layer include polyvinyl carbazole and derivatives thereof, and polymers containing aromatic amines such as polyarylene derivatives having aromatic amines in the side chain or main chain, arylamine derivatives, triphenyldiamine derivatives and the like. Moreover, the film-forming method of an interlayer layer is a method by film-forming from a solution, when using high molecular weight material.

  For forming an interlayer layer from a solution, known wet film forming methods such as spin coating, casting, microgravure coating, gravure coating, bar coating, roll coating, wire bar coating, Coating methods such as dip coating method, spray coating method, screen printing method, flexographic printing method, offset printing method, ink jet printing method, capillary coating method, nozzle coating method and the like can be used.

  The thickness of the interlayer may be selected to be an optimum value depending on the material to be used, and may be selected so that the driving voltage and the light emission efficiency become appropriate values, usually 1 nm to 1 μm, preferably 2 to 500 nm, More preferably, it is 5-200 nm.

  On the other hand, for the electron injection layer, an electron injection material is used which exhibits an excellent electron injection effect on the light emitting layer and can form an electron injection layer excellent in adhesion to the cathode interface and thin film formation. Examples of such electron injection materials include metal complex compounds, nitrogen-containing five-membered ring derivatives, fluorenone derivatives, anthraquinodimethane derivatives, diphenoquinone derivatives, thiopyrandioxide derivatives, perylene tetracarboxylic acid derivatives, fluorenylidene methane Derivatives, anthrone derivatives, silole derivatives, triaryl phosphine oxide derivatives, polyquinoline and its derivatives, polyquinoxaline and its derivatives, polyfluorene and its derivatives, calcium acetylacetonate, sodium acetate and the like. In addition, inorganic / organic composite materials in which metals such as cesium are doped to bathophenanthroline (Proceeds of the Polymer Society of Japan, Vol. 50, No. 4, p. 660, published 2001) and the 50th Conference on Applied Physics Proceedings of the lecture No. BCP, TPP, T5MPyTZ, etc. described on page 3, 1402 in 2003 can also be mentioned as an example of the electron injecting material, but a thin film necessary for device preparation can be formed, electrons from the cathode can be injected, and electrons can be transported. The material is not particularly limited as long as it is a material.

  Among the above-mentioned electron injecting materials, metal complex compounds, nitrogen-containing five-membered ring derivatives, silole derivatives and triarylphosphine oxide derivatives can be mentioned. Preferred metal complex compounds usable in the present invention are metal complexes of 8-hydroxyquinoline or derivatives thereof. Specific examples of metal complexes of 8-hydroxyquinoline or derivatives thereof include tris (8-hydroxyquinolinate) aluminum, tris (2-methyl-8-hydroxyquinolinate) aluminum, tris (4-methyl-8-) Hydroxyquinolinate) aluminum, tris (5-methyl-8-hydroxyquinolinate) aluminum, tris (5-phenyl-8-hydroxyquinolinate) aluminum, bis (8-hydroxyquinolinate) (1-naphtholate) ) Aluminum, bis (8-hydroxyquinolinate) (2-naphtholate) aluminum, bis (8-hydroxyquinolinate) (phenolate) aluminum, bis (8-hydroxyquinolinate) (4-cyano-1-naphtholate) ) Aluminum, bis (4-methyl-8) Hydroxyquinolinate) (1-naphtholato) aluminum, bis (5-methyl-8-hydroxyquinolinate) (2-naphtholate) aluminum, bis (5-phenyl-8-hydroxyquinolinate) (phenolate) aluminum, Bis (5-cyano-8-hydroxyquinolinate) (4-cyano-1-naphtholate) aluminum, bis (8-hydroxyquinolinate) chloroaluminum, bis (8-hydroxyquinolinate) (o-cresolate) Aluminum complex compounds such as aluminum, tris (8-hydroxyquinolinate) gallium, tris (2-methyl-8-hydroxyquinolinate) gallium, tris (4-methyl-8-hydroxyquinolinate) gallium, tris 5-Methyl-8-hydroxyquinolinate Gallium, tris (2-methyl-5-phenyl-8-hydroxyquinolinate) gallium, bis (2-methyl-8-hydroxyquinolinate) (1-naphtholate) gallium, bis (2-methyl-8-hydroxy) Quinolinate) (2-naphtholate) gallium, bis (2-methyl-8-hydroxyquinolinate) (phenolate) gallium, bis (2-methyl-8-hydroxyquinolinate) (4-cyano-1-naphtholate) ) Gallium, bis (2,4-dimethyl-8-hydroxyquinolinate) (1-naphtholate) gallium, bis (2,5-dimethyl-8-hydroxyquinolinate) (2-naphtholate) gallium, bis (2 -Methyl-5-phenyl-8-hydroxyquinolinate) (phenolate) gallium, bis (2-methyl-5-) Cyano-8-hydroxyquinolinate) (4-cyano-1-naphtholate) gallium, bis (2-methyl-8-hydroxyquinolinate) chlorogallium, bis (2-methyl-8-hydroxyquinolinate) ( 8-hydroxyquinolinate lithium, bis (8-hydroxyquinolinate) copper, bis (8-hydroxyquinolinate) manganese, bis (10-hydroxybenzo [h, in addition to gallium complex compounds such as o-cresolato) gallium And metal complexes such as beryllium, beryllium, bis (8-hydroxyquinolinate) zinc, and bis (10-hydroxybenzo [h] quinolinate) zinc.

  Further, among electron injecting materials that can be suitably used in the present invention, preferable nitrogen-containing five-membered ring derivatives include oxazole derivatives, thiazole derivatives, oxadiazole derivatives, thiadiazole derivatives, and triazole derivatives, and specifically, 2,5-bis (1-phenyl) -1,3,4-oxazole, 2,5-bis (1-phenyl) -1,3,4-thiazole, 2,5-bis (1-phenyl) -1 , 3,4-oxadiazole, 2- (4'-tert-butylphenyl) -5- (4 "-biphenyl) 1,3,4-oxadiazole, 2,5-bis (1-naphthyl)- 1,3,4-oxadiazole, 1,4-bis [2- (5-phenyloxadiazolyl)] benzene, 1,4-bis [2- (5-phenyloxadiazolyl) -4-tert- Butylbenzene ], 2- (4′-tert-butylphenyl) -5- (4 ′ ′-biphenyl) -1,3,4-thiadiazole, 2,5-bis (1-naphthyl) -1,3,4 Thiadiazole, 1,4-bis [2- (5-phenylthiadiazolyl)] benzene, 2- (4′-tert-butylphenyl) -5- (4 ′ ′-biphenyl) -1,3,4-triazole And 2,5-bis (1-naphthyl) -1,3,4-triazole, 1,4-bis [2- (5-phenyltriazolyl)] benzene and the like.

Furthermore, as materials that can be used for the electron injection layer, inorganic oxides such as zinc oxide (ZnO _x ), titanium oxide (TiO _x ), and the like, and doped materials thereof can also be mentioned.

  Further, among the electron injection materials usable in the present invention, specific examples of particularly preferable oxadiazole derivatives are shown in Table 4.

  Among the electron injection materials that can be suitably used in the present invention, specific examples of particularly preferable triazole derivatives are shown in Table 5. In Table 5, Ph represents a phenyl group.

  Among the electron injection materials that can be suitably used in the present invention, specific examples as preferable silole derivatives are shown in Table 6.

  Furthermore, for the hole blocking layer, a hole blocking material that can prevent holes that have passed through the light emitting layer from reaching the electron injecting layer and that can form a layer excellent in thin film formability is used. Examples of such hole blocking materials include aluminum complex compounds such as bis (8-hydroxyquinolinate) (4-phenylphenolate) aluminum, and bis (2-methyl-8-hydroxyquinolinate) ( Examples include gallium complex compounds such as 4-phenylphenolate) gallium, and nitrogen-containing condensed aromatic compounds such as 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP).

As a light emitting layer of the electroluminescent element of the present invention, one having the following functions is preferable.
Injection function: A function that can inject holes from the anode or hole injection layer when an electric field is applied, and a function that can inject electrons from the cathode or electron injection layer Transport function: injected electric charges (electrons and holes) to the electric field Function to move by force light emitting function; function to provide a field of electron and hole recombination and connect it to light emission However, there is a difference between the ease of hole injection and the ease of electron injection. Also, the transport ability represented by the mobility of holes and electrons may be large or small.

When the semiconductor layer composed of the semiconductor nanoparticle 2 of the present invention is used as a light emitting layer, fluorescent brightening agents such as benzothiazole, benzimidazole and benzoxazole, metal chelated oxinoid compounds, styryl benzene in the light emitting layer Additional compounds can be included.
Moreover, other light emitting layers other than the semiconductor layer which consists of the semiconductor nanoparticle 2 of this invention can also be provided, and compounds, such as a benzothiazole type, can also be used for formation of the said other light emitting layer.
Compounds such as benzothiazole series are suitable for obtaining blue to green emission.

  As a specific example of these compounds, the compound currently indicated by Unexamined-Japanese-Patent No. 59-194393 can be mentioned, for example. Still other useful compounds are listed in Chemistry of Synthetic Soybean (1971) pages 628-637 and page 640.

  As said metal chelated oxinoid compound, the compound currently disclosed by Unexamined-Japanese-Patent No. 63-295695 can be used, for example. As a typical example thereof, 8-hydroxyquinoline metal complexes such as tris (8-quinolinol) aluminum and the like, and dilithium epintridione can be mentioned as preferable compounds.

  Further, as the styrylbenzene-based compound, those disclosed in, for example, European Patent No. 0319881 and European Patent No. 0373582 can be used. And, a distyrylpyrazine derivative disclosed in JP-A-2-252793 can also be used as a material of the light emitting layer. Besides these, polyphenyl compounds disclosed in EP 0 387 715 can also be used as the material of the light emitting layer.

  Furthermore, in addition to the above-mentioned fluorescent whitening agents, metal chelated oxinoid compounds and styrylbenzene compounds, for example, 12-phthaloperinone (J. Appl. Phys., Vol. 27, L713 (1988)), 1,4- Diphenyl-1,3-butadiene, 1,1,4,4-tetraphenyl-1,3-butadiene (above Appl. Phys. Lett., Vol. 56, L 799 (1990)), Naphthalimide derivatives 2-305886), perylene derivatives (JP-A-2-189890), oxadiazole derivatives (JP-A-2-216791, or disclosed by Hamada et al. At the 38th Joint Conference on Applied Physics) Oxadiazole derivatives), aldazine derivatives (Japanese Patent Laid-Open No. 2-220393), pyrazirin Conductor (Japanese Patent Laid-Open No. 2-220394), cyclopentadiene derivative (Japanese Patent Laid-Open No. 2-289675), pyrrolopyrrole derivative (Japanese Patent Laid-open No. 2-296891), styrylamine derivative (Appl. Phys. Lett., 56) Volume, L799 (1990), coumarin compounds (Japanese Patent Application Laid-Open No. 2-191694), International Patent Publication WO 90/13148, and Appl. Phys. Lett., Vol 58, 18, P 1982 (1991). Polymer compounds, 9,9 ′, 10,10′-tetraphenyl-2,2′-bianthracene, PPV (polyparaphenylene vinylene) derivatives, polyfluorene derivatives, copolymers thereof and the like, for example, 2] to those having the structures of the general formula [4].

(Wherein, R ^x1 and R ^X2 each independently represent a monovalent aliphatic hydrocarbon group, and n1 represents an integer of 3 to 100).

(Wherein, R ^x3 and R ^X4 each independently represent a monovalent aliphatic hydrocarbon group, and n2 and n3 each independently represent an integer of 3 to 100).

General formula [4]

(Wherein, R ^X5 and R ^X6 each independently represent a monovalent aliphatic hydrocarbon group, n4 and n5 each independently represent an integer of 3 to 100. Ph represents a phenyl group.)

In addition, general formula (Rs-Q) _2- Al-O-L3 (wherein L3 is a hydrocarbon having 6 to 24 carbon atoms containing a phenyl moiety) described in JP-A-5-258862 and the like. , O-L3 is a phenolato ligand, Q is a substituted 8-quinolinolate ligand, Rs is sterically bound to the aluminum atom with more than two substituted 8-quinolinolate ligands Compounds having the 8-quinolinolate ring substituent selected to interfere are also specifically mentioned: bis (2-methyl-8-quinolinolate) (para-phenylphenolate) aluminum (III) And bis (2-methyl-8-quinolinolato) (1-naphtholate) aluminum (III) and the like.

Although there is no restriction | limiting in particular as a light emitting layer in the case of obtaining white light emission, The following can be used. What defines the energy level of each layer of an organic electroluminescent laminated structure, and is made to light-emit using a tunnel injection (European patent 0390551).
Similarly, a device using a tunnel injection in which a white light emitting device is described as an example (Japanese Patent Application Laid-Open No. 3-230584). A light emitting layer having a two-layer structure is described (Japanese Patent Application Laid-Open Nos. 2-220390 and 2-216790). A light emitting layer is divided into a plurality of parts each made of materials having different light emission wavelengths (Japanese Patent Laid-Open No. 4-51491). The thing of the structure which laminated | stacked the blue light-emitting body (fluorescent peak 380-480 nm) and the green light-emitting body (480-580 nm), and was made to contain a red fluorescent substance (Unexamined-Japanese-Patent No. 6-207170). A structure in which the blue light emitting layer contains a blue fluorescent dye, the green light emitting layer has a region containing a red fluorescent dye, and further contains a green fluorescent substance (JP-A-7-142169).

Further, as the material used for the anode of the electroluminescent device of the present invention, a material having a high work function (4 eV or more) metal, an alloy, an electrically conductive compound or a mixture thereof is preferably used. Specific examples of such an electrode material include metals such as Au, and conductive materials such as CuI, ITO, SnO ₂ , and ZnO. In order to form this anode, a thin film can be formed on these electrode materials by a method such as vapor deposition or sputtering. The anode desirably has a characteristic such that the transmittance of the anode to the light emission is greater than 10% when light emitted from the light emitting layer is taken out from the anode. The sheet resistance of the anode is preferably several hundreds Ω / sq or less. Furthermore, although the film thickness of an anode is based also on material, 10 nm-1 micrometer, Preferably it selects in 10-200 nm.

  Further, as the material used for the cathode of the electroluminescent device of the present invention, a material having a small work function (4 eV or less), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such an electrode material include sodium, sodium-potassium alloy, magnesium, lithium, magnesium-silver alloy, aluminum / aluminum oxide, aluminum-lithium alloy, indium, rare earth metals and the like. The cathode can be produced by forming a thin film of such an electrode material by a method such as vapor deposition or sputtering. Here, when light emission from the light emitting layer is taken out from the cathode, the transmittance of the cathode to the light emission is preferably greater than 10%. The sheet resistance as the cathode is preferably several hundred ohms / square or less, and the film thickness is usually 10 nm to 1 μm, preferably 50 to 200 nm.

  With regard to the method of producing the electroluminescent device of the present invention, the above materials and methods form the anode, the light emitting layer, the hole injection layer as needed, and the electron injection layer as needed, and finally the cathode do it. In addition, the electroluminescent element can be manufactured in the reverse order to the above from the cathode to the anode.

  This electroluminescent element is fabricated on a translucent substrate. The light transmitting substrate is a substrate for supporting the electroluminescent element, and the light transmitting property thereof is preferably one having a light transmittance of 50% or more, preferably 90% or more, in the visible region of 400 to 700 nm. It is preferable to use a smooth substrate.

  These substrates have mechanical and thermal strengths and are not particularly limited as long as they are transparent, but for example, glass plates, synthetic resin plates, etc. are suitably used. Examples of the glass plate include plates made of soda lime glass, glass containing barium and strontium, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, quartz and the like. Moreover, as a synthetic resin board, boards, such as a polycarbonate resin, an acrylic resin, a polyethylene terephthalate resin, polyether sulfide resin, poly sulfone resin, are mentioned.

  In the electroluminescent device of the present invention, the layers other than the semiconductor layer consisting of the semiconductor nanoparticles 2 can be formed by vacuum deposition, electron beam irradiation, sputtering, plasma, dry film forming methods such as ion plating, spin coating, Any of wet film formation methods such as dipping and flow coating can be applied. In addition, JP 2002-534782 and S.E. T. Lee, et al. , Proceedings of SID'02, p. Methods such as LITI (Laser Induced Thermal Imaging), printing (offset printing, flexographic printing, gravure printing, screen printing), inkjet, etc. described in 784 (2002) can also be applied.

  The organic layer is preferably a molecular deposition film. Here, a molecular deposition film is a thin film deposited and formed from a material compound in a gas phase, or a film solidified and formed from a material compound in a solution or liquid phase, and this molecular deposition film is usually used. And the thin film (molecular accumulated film) formed by the LB method can be classified according to the difference in the aggregation structure, the higher order structure, and the functional difference resulting therefrom. Further, as disclosed in JP-A-57-51781, a binder such as a resin and a material compound are dissolved in a solvent to form a solution, which is then thinned by spin coating or the like. , An organic layer can be formed. The film thickness of each layer is not particularly limited, but if the film thickness is too thick, a large applied voltage is required to obtain a constant light output, and the efficiency deteriorates, and conversely, if the film thickness is too thin, pinholes etc. This makes it difficult to obtain sufficient light emission luminance even if an electric field is applied. Therefore, the film thickness of each layer is suitably in the range of 1 nm to 1 μm, and more preferably in the range of 10 nm to 0.2 μm.

  Further, in order to improve the stability of the electroluminescent element against temperature, humidity, atmosphere and the like, a protective layer may be provided on the surface of the element, or the entire element may be covered or sealed with a resin or the like. In particular, when covering or sealing the entire element, a photocurable resin which is cured by light is suitably used.

  The current applied to the electroluminescent device of the present invention is usually direct current, but pulse current or alternating current may be used. The current value and the voltage value are not particularly limited as long as they do not break the element, but it is desirable to efficiently emit light with as small electrical energy as possible in consideration of the power consumption and the life of the element.

  The driving method of the electroluminescent device of the present invention can be driven not only by the passive matrix method but also by the active matrix method. Further, as a method of extracting light from the organic EL element of the present invention, not only a method of bottom emission for extracting light from the anode side, but also a method of top emission for extracting light from the cathode side can be applied. These methods and techniques are described in Koji Kido, "All About Organic EL", Nippon Keizai Publisher (issued in 2003).

  As a main system of the full color system of the electroluminescent element of this invention, a three-color paint system, a color conversion system, and a color filter system are mentioned. The three-color application method includes an evaporation method using a shadow mask, an inkjet method, and a printing method. In addition, JP 2002-534782 and S.E. T. Lee, et al. , Proceedings of SID'02, p. The laser thermal transfer method (also called Laser Induced Thermal Imaging, also referred to as LITI method) described in 784 (2002) can also be used. The color conversion method is a method of converting a blue and green light having a longer wavelength than the blue through a color conversion (CCM) layer in which a fluorescent dye is dispersed, using a blue light emitting layer. The color filter method is a method of extracting light of three primary colors through a liquid crystal color filter using a white light emitting organic EL element, but in addition to these three primary colors, a part of white light is directly extracted and used for light emission Thus, the luminous efficiency of the entire device can be increased.

  Furthermore, the electroluminescent device of the present invention may adopt a microcavity structure. This is a structure in which the light emitting layer is sandwiched between the anode and the cathode, and the emitted light causes multiple interference between the anode and the cathode, but the reflectance and transmission of the anode and the cathode are transmitted. It is a technology to control the emission wavelength taken out from the element by positively utilizing the multiple interference effect by appropriately selecting the optical characteristics such as the ratio and the film thickness of the organic layer sandwiched by these. . This also makes it possible to improve the emission chromaticity. For the mechanism of this multiple interference effect, see J. Yamada et al. AM-LCD Digest of Technical Papers, OD-2, p. 77-80 (2002).

  As described above, the electroluminescent device using the semiconductor layer formed of the semiconductor nanoparticle 2 of the present invention can obtain light emission for a long time at a low driving voltage. Therefore, the present organic EL element is used as a flat panel display such as a wall-mounted television or various flat light emitters, and further, a light source such as a copying machine or a printer, a light source such as a liquid crystal display or meter, a display board, a marker lamp, etc. The application of

EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not particularly limited to the examples.
<Production Example 1>
An additive solution was prepared by heating and dissolving 0.55 g of anhydrous zinc acetate, 4.82 ml of dodecanethiol and 6 ml of oleylamine.
0.22 g of indium chloride and 10 ml of octylamine were placed in a reaction vessel and heated to 165 ° C. while blowing nitrogen gas. After the indium chloride was dissolved, 0.961 ml of diethylaminophosphine was injected in a short time, and the temperature was controlled at 165 ° C. for 20 minutes. It was then quenched and cooled to 40.degree.
Then, after the addition solution was injected, the solution was heated to 240 ° C., reacted at the same temperature for 2 hours, and allowed to cool to room temperature.
After leaving to cool, purification was performed by reprecipitation using hexane and ethanol. The solid content concentration was adjusted to 10% by mass using toluene to obtain a dispersion of semiconductor nanoparticles (hereinafter referred to as QD dispersion 1). The particle size of the obtained semiconductor nanoparticles was 10 nm.
The semiconductor nanoparticles were manufactured so that InP was a core and ZnS was a shell.

Production Example 2 Production Example of Ligand (Block Copolymer) in Table 1 (1) 6.38 g (50 mmol) of metallic tellurium (trade name: Tellurium (-40 mesh), Aldrich) was suspended in 50 ml of THF. To this, 34.4 ml (55 mmol) of n-butyllithium (Aldrich, 1.6 M solution in hexane) was slowly added dropwise at room temperature (10 minutes). The reaction solution was stirred until the metal tellurium disappeared completely (20 minutes). To this reaction solution, 10.7 g (55 mmol) of ethyl-2-bromo-isobutyrate was added at room temperature and stirred for 2 hours. After completion of the reaction, the solvent is concentrated under reduced pressure and then distilled under reduced pressure to obtain 8.98 g (yield 59.5%) of ethyl 2-methyl-2-n-butyl-teranyl-propionate (BTEE) as a yellow oil. I got
Next, 3.86 g (2 mol) of N-vinylcarbazole, 1.94 g of deionized water, 0.360 g of BTEE, and 2,2'-azobis (4-methoxy-2,4) in a flask equipped with an argon gas inlet tube and a stirrer. 0.0259 g of 4-dimethylvaleronitrile) (manufactured by Wako Pure Chemical Industries, Ltd.) was charged, and reacted at 30 ° C. for 24 hours.
In the above reaction solution, 0.36 g (0.5 mol) of acrylic acid (manufactured by Sigma Aldrich Japan Co., Ltd.) previously substituted with argon, 2,2′-azobis (2,4-dimethyl valeronitrile) (manufactured by Otsuka Chemical Co., Ltd.) 0. A mixed solution of 0076 g, 8.00 g of tetrahydrofuran and 3.59 g of methanol was added and allowed to react at 45 ° C. for 45 hours.
After completion of the reaction, 48.00 g of THF was added to the reaction solution and poured into 300 ml of heptane under stirring. The precipitated polymer was subjected to suction filtration and dried to obtain a ligand (1) in Table 1 as a block copolymer.
In the case other than (1) in Table 1, the block copolymer type ligand can be similarly obtained by appropriately selecting the raw materials and the amount thereof as appropriate.

Example 1
QD Dispersion 1 was diluted with toluene to a solids concentration of 0.5 wt%.
A ligand of block copolymer type shown in (1) of Table 1 was dissolved in toluene to prepare a 0.5 wt% ligand solution, and a double weight was added to the QD dispersion 1 and stirred for 12 hours.
Thereafter, purification was performed by reprecipitation using hexane and ethanol. The dispersion was prepared to a solid concentration of 10% by mass using toluene, to obtain a dispersion liquid of the semiconductor nanoparticles 2 of the present invention coated with a ligand.
A part of the obtained dispersion is diluted to 2 × 10 ^-3 wt%, and the luminescence quantum yield is measured under the conditions of an excitation wavelength of 400 nm using an absolute PL quantum yield measurement device C9920-02 manufactured by Hamamatsu Photonics Co., Ltd. did. The result was 89.5%.
Furthermore, the remaining part of the obtained dispersion was tightly sealed and heated at 80 ° C. for 24 hours, and then cooled to room temperature, and the luminescence quantum yield was similarly measured. Here, “a luminescence quantum yield after heating and holding / a luminescence quantum yield before heating and holding” was obtained, and it was 0.95. The results are also shown in Table 7. Note that “emission quantum yield after heating and holding 発 光 emission quantum yield before heating and holding” is abbreviated as “retention of the dispersion after heating test”.

Examples 2 to 99
Semiconductor nanoparticles in the same manner as in Example 1 except that the block copolymer type ligand in Table 1 described in Table 7 is changed instead of the block copolymer type ligand shown in (1) of Table 1 2 was adjusted, and the initial luminescence quantum yield and the retention of the dispersion after the heating test were determined. The results are shown in Table 7.

Comparative Example 1
With the QD dispersion 1 with dodecanethiol as a ligand, the initial luminescence quantum yield and the retention of the dispersion after a heating test were determined. The results are shown in Table 7. As a special note, the QD dispersion 1 after heating and holding had turbidity. This is a phenomenon not seen in the example.

Example 101
The dispersion (solid content: 10% by mass) of the semiconductor nanoparticle 2 of the present invention obtained in Example 1 is diluted 20 times, and coated on a glass substrate under the conditions of 1000 rpm for 30 seconds using a spin coater. The semiconductor layer was processed and dried under a nitrogen atmosphere at room temperature for 5 minutes to form a semiconductor layer of the present invention on a glass substrate.
The emission quantum yield of the obtained semiconductor layer was measured under the conditions of an excitation wavelength of 400 nm using an absolute PL quantum yield measurement device C9920-02 manufactured by Hamamatsu Photonics. The result was 85.0%, and the value of “emission quantum yield of semiconductor layer” / “emission quantum yield of dispersion” was calculated to be 0.89. Note that “emission quantum yield of semiconductor layer” / “emission quantum yield of dispersion liquid” is abbreviated as “ratio of emission quantum yield of semiconductor layer to dispersion liquid”.
Furthermore, the glass substrate with the semiconductor layer was heated and held at 110 ° C. for 24 hours, and then cooled to room temperature, and the luminescence quantum yield was similarly measured. Here, “a luminescence quantum yield after heating and holding / a luminescence quantum yield before heating and holding” was obtained, and it was 0.95. The results are also shown in Table 8. Note that “emission quantum yield after heating and holding ÷ emission quantum yield before heating and holding” is abbreviated as “retention of semiconductor layer after heating test”.

<Example 102 to Example 199>
The dispersion of the semiconductor nanoparticle 2 of the present invention obtained in Example 1 is changed to the one obtained in Example 2 or later as described in Table 8 in the same manner as in Example 101, except for The semiconductor layer was formed, and the light emission quantum yield of the semiconductor layer, the ratio of the light emission quantum yield of the semiconductor layer to the dispersion liquid, and the retention after the heat test of the semiconductor layer were determined. The results are shown in Table 8.

Comparative Example 101
A semiconductor layer is prepared in the same manner as in Example 101 except that the QD dispersion liquid 1 having dodecanethiol as a ligand is used instead of the dispersion liquid of semiconductor nanoparticles 2 of the present invention obtained in Example 1, evaluated. The results are shown in Table 8.

<Example of electroluminescent device>
Hereinafter, the electroluminescent element of the present invention will be described by way of the following examples, but the present invention is not limited to the following examples. In the examples, mixing ratios all indicate weight ratios unless otherwise noted. The deposition (vacuum deposition) was performed in a vacuum of 10 ⁻⁶ Torr under conditions where temperature control such as heating and cooling of the substrate was not performed. The light emission characteristics of the element were measured using an electroluminescent element with a light emitting element area of 2 mm × 2 mm.

Example 201
PEDOT / PSS (poly (3,4-ethylenedioxy) -2,5-thiophene / polystyrene sulfonic acid, CLEVIOUS® P VP CH8000 manufactured by Heraeus) is spin-coated on a cleaned ITO electrode-attached glass plate It coated by the method, it was made to dry at 110 degreeC for 20 minutes, and the hole injection layer with a film thickness of 35 nm was obtained.
Next, poly (N-vinylcarbazole) is dissolved in monochlorobenzene at a concentration of 1.0% by weight, coated by spin coating, and dried at 110 ° C. for 20 minutes to form holes of 35 nm thickness A transport layer was formed.
On top of that, the dispersion (solid content concentration: 10% by mass) of the semiconductor nanoparticle 2 of the present invention obtained in Example 1 is diluted 35 times and coated by spin coating, under a nitrogen atmosphere at room temperature. And dried for 5 minutes to form a 20 nm light emitting layer.
An isopropanol dispersion N-10 of zinc oxide manufactured by Avantama Co. was applied thereon by a spin coating method, and dried by heating on a hot plate at 80 ° C. for 20 minutes to form an electron transport layer of 80 nm.
Lastly, aluminum (Al) was deposited to a thickness of 200 nm to form an electrode, whereby an electroluminescent device was obtained.
This device exhibited a red emission with an external quantum efficiency of 4.5% and an emission luminance of 25000 (cd / m ² ) at 8 V, the peak wavelength of the emission spectrum was 625 nm, and the full width at half maximum was 25 nm. The half life of the device was measured when the device was driven at a constant current at room temperature and a light emission luminance of 1000 (cd / m ² ). In addition, luminous efficiency when driven at a current density of 10 (mA / cm ² ), and relative luminance after continuous driving for 100 hours in an environment of 80 ° C. (= (luminance after 100 hours) / (initial luminance) Was measured. The results are shown in Table 9.

Examples 202 to 299
An electroluminescent device was prepared in the same manner as in Example 201 except that the dispersion of semiconductor nanoparticles 2 of the present invention obtained in Example 1 was changed to those obtained in Example 2 or later as described in Table 9. Created and evaluated similarly. The results are shown in Table 9.

Comparative Example 201
An electroluminescent element is prepared in the same manner as in Example 201 except that the QD dispersion liquid 1 having dodecanethiol as a ligand is used instead of the dispersion liquid of the semiconductor nanoparticles 2 of the present invention obtained in Example 1, Evaluated. The results are shown in Table 9.

As described above, according to the present invention, semiconductor nanoparticles exhibiting excellent performance in electrical characteristics, light emission characteristics, dispersion stability, stability in a film state, and characteristics as an electroluminescent element can be obtained.

Claims (11)

A semiconductor nanoparticle 2 having an average particle diameter of 50 nm or less, in which at least a part of the surface of the semiconductor nanoparticle 1 is covered with the following ligand,
The ligand has a main chain not having a conjugated structure, and a side chain bonded to the main chain,
The side chain has a conjugated structure and an adsorptive group,
Semiconductor nanoparticles 2. The semiconductor nanoparticle 1 has a core made of a first semiconductor, and a shell made of a second semiconductor which covers at least a part of the core and is different from the first semiconductor.
The semiconductor nanoparticle 2 according to claim 1.   The semiconductor nanoparticle 2 according to claim 2, wherein the core and the shell are each independently composed of a II-VI semiconductor or a III-V semiconductor. The ligand has a main chain not having a conjugated structure, and a plurality of side chains attached to the main chain,
At least one of the plurality of side chains has a conjugated structure and does not have an adsorptive group,
At least one of the other side chains among the plurality of side chains has an adsorptive group and does not have a conjugated structure,
The semiconductor nanoparticle 2 according to any one of claims 1 to 3.   The semiconductor nanoparticle 2 according to claim 4, wherein the side chain having a conjugated structure and not having an adsorptive group and the side chain having an adsorptive group and having no conjugated structure respectively form a block. The ligand has a main chain not having a conjugated structure, and a plurality of side chains attached to the main chain,
At least one of the side chains has a conjugated structure and an adsorptive group,
The semiconductor nanoparticle 2 according to any one of claims 1 to 3. An adsorptive group is an amino group, a hydroxyl group, a carboxyl group, a thiol group, a sulfuric acid group, a sulfonic acid group, a phosphine group, a phosphonic acid group,-(P = O) R'R ", a cyano group, -CH = C (CN) The semiconductor nanoparticle 2 according to any one of claims 1 to 6, which is at least one functional group selected from the group consisting of ₂ ) and -CH = C (CN) COOH.
Here, R′R ′ ′ represents an aliphatic hydrocarbon group.   The dispersion liquid containing the semiconductor nanoparticle 2 of any one of Claims 1-7, and a liquid dispersion medium.   The semiconductor layer which consists of the semiconductor nanoparticle 2 of any one of Claims 1-7. A method of manufacturing a laminate comprising a base material and a semiconductor layer comprising semiconductor nanoparticles 2;
Coating the dispersion according to claim 8 on a substrate and drying the liquid dispersion medium
Method of manufacturing a laminate. With the anode,
With the cathode,
The semiconductor layer according to claim 9, between the anode and the cathode,
An electroluminescent device equipped.