JP7238636B2 - Quantum dots, quantum dot-containing compositions, inkjet inks and printed matter - Google Patents

Description

The present invention provides a quantum dot, a quantum dot-containing composition containing the quantum dot, an inkjet ink, and a printed material formed using the inkjet ink.

Quantum dots are extremely small particles (dots) formed to confine electrons in a minute space in order to develop unique optical properties according to quantum mechanics. A single quantum dot has a diameter of 1 nanometer to several tens of nanometers and is composed of approximately 10,000 or less atoms. It has been attracting attention in recent years because the wavelength of the emitted fluorescence can be controlled continuously by the size of the particles, and because the wavelength distribution of the fluorescence intensity is highly symmetrical and sharp emission can be obtained.
Quantum dots can adjust fluorescence to a wavelength that easily penetrates the human body and can be delivered anywhere in the body. Patent Literature 1), and investigations are underway to develop it into electronics and photonics applications (Patent Literatures 2 and 3) as a bright light-emitting material and a wavelength conversion material.

Quantum yield of fluorescence is one of the required properties for these applications. In order to improve the fluorescence quantum yield, Non-Patent Document 2 discloses an example in which semiconductor fine particles made of In—P are coated with myristic acid, which is an organic aliphatic carboxylic acid.

However, when the quantum dots are mixed with a solvent, a monomer, a resin, or the like, there arises a problem that not only the viscosity stability is lowered, but also the fluorescence quantum yield after coating or printing is significantly lowered.

JP-A-2006-216560 JP 2008-112154 A JP 2009-251129 A

Shenlong, "Semiconductor Quantum Dots, Their Synthesis Method and Application to Life Science", Production and Technology, Vol.63, No.2, 2011, p58-p65 Journal of the American Chemical Society 2007 129 15432-15433

Therefore, an object of the present invention is to have an excellent fluorescence quantum yield, to have good viscosity stability even when it is made into a composition, and to maintain an excellent fluorescence quantum yield even after coating and printing. It is to provide a quantum dot and a quantum dot-containing composition, inkjet ink and printed matter using the quantum dot.

In order to solve the above-mentioned problems, the present inventors have made intensive studies and found that by using semiconductor fine particles surface-treated with a treatment agent having a specific structure, the quantum efficiency of fluorescence is improved and a composition is obtained. Viscosity stability in the case and maintenance of fluorescence quantum efficiency after printing were achieved.

That is, the present invention relates to inventions [1] to [8] below.

[1] A quantum dot containing semiconductor fine particles,
The semiconductor fine particles have at least one partial structure selected from the group consisting of a carbazole skeleton, a diarylamine skeleton, a triarylamine skeleton, a quinoline skeleton, and an indole skeleton, and at least one kind selected from the group consisting of a carboxyl group and a sulfanyl group. Quantum dots surface-treated with a treatment agent having adsorption sites for

[2] The quantum dots according to [1], wherein the treatment agent is represented by the following general formula (1), general formula (2), or general formula (3).

General formula (1)

[In general formula (1),
X ¹ is a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, or an optionally substituted acyl group,
R ¹ to R ⁸ each independently represent a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted alkoxy group, or a substituent An aryloxy group which may have a substituent, an acyl group which may have a substituent, an amino group which may have a substituent, a (poly)organosiloxane group which may have a substituent, a carboxyl group or a sulfanyl group,
At least one of X ¹ and R ¹ to R ⁸ is a group having a carboxyl group or a group having a sulfanyl group. ]

general formula (2)

[In general formula (2),
R ¹¹ to R ²⁵ each independently represent a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted alkoxy group, or a substituent an aryloxy group which may have a substituent, an acyl group which may have a substituent, a (poly)organosiloxane group which may have a substituent, a nitro group, an amino group which may have a substituent, It is a carboxyl group or a sulfanyl group, and at least one of R ¹¹ to R ²⁵ is a group having a carboxyl group or a group having a sulfanyl group. ]

General formula (3)

[In general formula (3),
X ² is a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group (excluding a phenyl group), or an optionally substituted acyl group,
R ²⁶ to R ³⁵ each independently represent a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted alkoxy group, or a substituent An aryloxy group which may have a substituent, a (poly)organosiloxane group which may have a substituent, an amino group which may have a substituent, an acyl group which may have a substituent, a carboxyl group or a sulfanyl group,
At least one of X ² and R ²⁶ to R ³⁵ is a group having a carboxyl group or a group having a sulfanyl group. ]

[3] The quantum dots according to [1] or [2], wherein the semiconductor fine particles are compound semiconductors.

[4] The quantum dot according to any one of [1] to [3], wherein the semiconductor fine particles are core-shell type.

[5] A quantum dot-containing composition containing the quantum dots according to any one of [1] to [4] and a solvent.

[6] An inkjet ink containing the quantum dot-containing composition according to [5] and having a viscosity of 3 to 50 mPa·s.

[7] A printed material formed from the quantum dot-containing composition according to [5] or the inkjet ink according to [6].

[8] A light-emitting device having an anode, a light-emitting layer and a cathode on a substrate, wherein the light-emitting layer contains the quantum dots according to any one of [1] to [4].

According to the present invention, it has an excellent fluorescence quantum yield, has good viscosity stability even when it is made into a composition, and can maintain an excellent fluorescence quantum yield even after coating and printing. Quantum dots and quantum dot-containing compositions, inkjet inks, and printed matter using the quantum dots can be provided. A printed material using the quantum dots has a good retention rate of fluorescence quantum yield, and thus can be suitably used as a light-emitting layer of an electroluminescent device.

<Quantum dots>
The quantum dot of the present invention includes at least one partial structure selected from the group consisting of a carbazole skeleton, a diarylamine skeleton, a triarylamine skeleton, a quinoline skeleton and an indole skeleton, and at least one selected from the group consisting of a carboxyl group and a sulfanyl group. It is characterized by being surface-treated with a treating agent having one type of adsorption site.
The present invention will be described in detail below.

<Semiconductor microparticles>
The semiconductor fine particles in the present invention are semiconductors containing an inorganic substance as a component, and may have a single composition, a core-shell type, or a multi-layer structure of three or more layers.
The semiconductor is selected from the group of elements represented by Group 1 elements, Group 2 elements, Group 10 elements, Group 11 elements, Group 12 elements, Group 13 elements, Group 14 elements, Group 15 elements, Group 16 elements and Group 17 elements. It is a semiconductor made of a compound containing at least two selected elements. Compound semiconductors are more preferred.
The compound semiconductor is selected from the group of elements represented by Ag, Cu, Zn, Cd, B, Al, Ga, In, C, Si, Ge, Sn, N, P, As, Sb, Pb, S, Se and Te. It is a semiconductor made of a compound containing at least two kinds of elements. More preferably, the semiconductor is a compound containing at least two elements selected from the group of elements represented by Zn, B, Al, Ga, In, C, Si, Ge, Sn, N, P, S and Te. .
For applications that emit visible light, a semiconductor containing In as a constituent element is more preferable because of its narrow bandgap.

A core-shell type semiconductor fine particle has a structure in which a core structure is covered with a semiconductor composed of a component different from that of the semiconductor forming the core. By using a semiconductor with a large bandgap for the shell, excitons (electron-hole pairs) generated by photoexcitation are confined within the core. As a result, the probability of non-radiative transition on the surface of the semiconductor fine particles is reduced, and the quantum yield of light emission and the stability of the fluorescence properties of the semiconductor quantum dots are improved, which is preferable.

The average particle size of the semiconductor fine particles including the core and shell is preferably 0.5 nm to 100 nm, and the particle size can be selected so that desired color development can be obtained. In the case of the core-shell type, one semiconductor fine particle may contain a plurality of shell fine particles. The average particle size of the semiconductor fine particles in the case of a single semiconductor composition and the average particle size of the core-shell type core are preferably 0.5 nm or more in terms of synthesis, and 10 nm or less improve the quantum confinement effect. It is preferable because the desired fluorescence can be easily obtained. Further, the average particle size of quantum dots containing ligands is preferably 2 nm to 1 μm. The shape of the quantum dots is not limited to spherical, but may be rod-like, disk-like, or other shapes.

The average particle diameter as used herein refers to a value obtained by observing semiconductor fine particles with a transmission electron microscope, randomly measuring the size of 30 particles, and adopting the average value thereof. At this time, since the semiconductor fine particles are accompanied by a processing agent, which will be described later, a scanning transmission electron microscope with energy dispersive X-ray analysis is used to identify the semiconductor material part, and then electrons are detected in the transmission electron microscope image. The particle diameter is measured by utilizing the fact that the semiconductor fine particle portion is imaged darker than the processing agent described later due to the difference in density.

<Treatment agent>
The treating agent in the present invention has at least one partial structure selected from the group consisting of a carbazole skeleton, a diarylamine skeleton, a triarylamine skeleton, a quinoline skeleton and an indole skeleton, and at least one selected from the group consisting of a carboxyl group and a sulfanyl group. It suffices to have one type of adsorption site, and one type can be used alone or two or more types can be used in combination. The triarylamine skeleton is preferably a triphenylamine skeleton, the indole skeleton includes an isoindole skeleton, and the quinoline skeleton includes an isoquinoline skeleton.

From the viewpoint of QY retention rate and viscosity stability when made into a composition, the treatment agent has at least one partial structure selected from the group consisting of a carbazole skeleton, a diarylamine skeleton and a triarylamine skeleton, a carboxyl group and a sulfanyl and at least one adsorption site selected from the group consisting of groups. This is considered to be due to the suppression of the aggregation of quantum dots as the steric repulsion increases. More preferably, a treating agent having a carbazole skeleton represented by the following general formula (A), a treating agent having a triarylamine skeleton represented by the following general formula (B), or a diaryl represented by the general formula (C) A processing agent having an amine skeleton.

General formula (A)

General formula (B)

General formula (C)

[In the general formulas (A) to (C),
X ¹ is a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted acyl group, a nitro group, a halogeno group, a formyl group, a nitrile a group, a carboxyl group or a sulfanyl group,
X ² is a hydrogen atom, an optionally substituted alkyl group, an optionally substituted acyl group, a nitro group, a halogeno group, a formyl group, a nitrile group, a carboxyl group or a sulfanyl group,
R ¹ to R ⁸ , R ¹¹ to R ²⁵ and R ²⁶ to R ³⁵ each independently represent a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, a substituted alkoxy group optionally having a group, aryloxy group optionally having a substituent, (poly)organosiloxane group optionally having a substituent, amino group optionally having a substituent, substituent an acyl group, a nitro group, a halogeno group, a formyl group, a nitrile group, a carboxyl group or a sulfanyl group, which may have
At least one of X ¹ , X ² , R ¹ to R ⁸ , R ¹¹ to R ²⁵ and R ²⁶ to R ³⁵ is a group having a carboxyl group or a group having a sulfanyl group. ]

More preferably, a treating agent having a carbazole skeleton represented by the following general formula (1), a treating agent having a triarylamine skeleton represented by the following general formula (2), or represented by the general formula (3) A treatment agent having a diarylamine skeleton.

General formula (1)

[In general formula (1),
X ¹ is a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, or an optionally substituted acyl group,
R ¹ to R ⁸ each independently represent a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted alkoxy group, or a substituent An aryloxy group which may have a substituent, an acyl group which may have a substituent, an amino group which may have a substituent, a (poly)organosiloxane group which may have a substituent, a carboxyl group or a sulfanyl group,
At least one of X ¹ and R ¹ to R ⁸ is a group having a carboxyl group or a group having a sulfanyl group. ]

general formula (2)

[In general formula (2),
R ¹¹ to R ²⁵ each independently represent a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted alkoxy group, or a substituent an aryloxy group which may have a substituent, an acyl group which may have a substituent, a (poly)organosiloxane group which may have a substituent, a nitro group, an amino group which may have a substituent, It is a carboxyl group or a sulfanyl group, and at least one of R ¹¹ to R ²⁵ is a group having a carboxyl group or a group having a sulfanyl group. ]

General formula (3)

[In general formula (3),
X ² is a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group (excluding a phenyl group), or an optionally substituted acyl group,
R ²⁶ to R ³⁵ each independently represent a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted alkoxy group, or a substituent An aryloxy group which may have a substituent, a (poly)organosiloxane group which may have a substituent, an amino group which may have a substituent, an acyl group which may have a substituent, a carboxyl group or a sulfanyl group,
At least one of X ² and R ²⁶ to R ³⁵ is a group having a carboxyl group or a group having a sulfanyl group. ]

The substituents in the general formulas (A) to (C) and (1) to (3) are described below.
The alkyl group is a linear, branched or cyclic alkyl group, from which some hydrogen atoms may be dropped to form double bonds or triple bonds. The molecular weight of the treatment agent is preferably small, and the number of carbon atoms in the alkyl group is preferably 1 to 30, in order to increase the content of semiconductor fine particles in the composition.
Examples of the alkyl group include linear alkyl groups such as methyl group, ethyl group, hexyl group, dodecyl group and eicosyl group; branched alkyl groups such as 2-ethylhexyl group; cyclic groups such as cyclohexyl group and 3-cyclohexylpropyl group; Alkyl groups; alkenyl groups such as ethenyl group and dodecene group; and alkynyl groups such as prop-2-yn-1-group and propargyl group.

The aryl group is a residue obtained by formally removing one hydrogen atom from an aromatic ring, more preferably a residue obtained by formally removing one hydrogen atom from an aromatic ring having 6 to 30 carbon atoms.
Examples of aromatic rings include benzene ring, naphthalene ring, pyrene ring, pyridine ring, pyrimidine ring, pyridazine ring, pyrazine ring, quinoline ring, furan ring, pyrrole ring, thiophene ring, imidazole ring, pyrazole ring, oxazole ring, and thiazole ring. , indole ring, benzimidazole ring, benzofuran ring, purine ring, acridine ring, phenothiazine ring, biphenyl group, or terphenyl group.

An alkoxy group is a functional group to which an alkyl group is bonded via an ether bond, and the alkyl group has the same meaning as the alkyl group in the general formulas (A) to (C) and (1) to (3) described above. be.

An aryloxy group is a functional group to which an aryl group is bonded via an ether bond, and the aryl group is synonymous with the aryl group in the above-described general formulas (A) to (C) and (1) to (3). is.

The acyl group is a functional group in which an alkyl group or an aryl group is bonded via a carbonyl group. is synonymous with the alkyl group and aryl group in

A (poly)organosiloxane group is a residue obtained by formally removing one hydrogen atom from a siloxane compound, and the silicon of the siloxane compound may be substituted with an alkyl group. The optionally substituted alkyl group has the same definition as the alkyl group in the general formulas (A) to (C) and (1) to (3). Examples of siloxane compounds include, for example, pentamethyldisiloxane, heptaethyltrisiloxane, undecamethyltetrasiloxane, trimethylsiloxydimethylsilanol, 1,1,3,3,tetramethyl-1,3-dihydroxydisiloxane or 1 , 1,3,3,5,5-hexamethyl-1,5-dihydroxy-trisiloxane and the like.
From the viewpoint of increasing the content of semiconductor fine particles in the composition, the molecular weight of the treatment agent is preferably small, and the number of repeating siloxane bonds is preferably 4 or less.

The amino group which may have a substituent includes an amino group and a substituted amino group, and examples of the substituent of the substituted amino group include an alkyl group, an aryl group and an acyl group. The above alkyl group, aryl group and acyl group are synonymous with the alkyl group, aryl group and acyl group in the above general formulas (A) to (C) and (1) to (3).

In addition, the alkyl group, aryl group, alkoxy group, amino group, aryloxy group and acyl group in general formulas (A) to (C) and (1) to (3) may have a substituent.
Substituents which may be present include, for example, a halogeno group, a cyano group, a hydroxy group, a nitro group, an alkoxy group, an alkyl group, an aralkyl group, an aryl group, an aryloxy group, a silyloxy group, a heterocyclicoxy group, and an acyloxy group. , carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, amino group (including anilino group), acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfamoylamino group, alkyl and arylsulfonylamino groups, sulfanyl groups, alkylthio groups, arylthio groups, heterocyclicthio groups, alkyl and arylsulfinyl groups, alkyl and arylsulfonyl groups, acyl groups, aryloxycarbonyl groups, alkoxycarbonyl groups, carbamoyl groups, imido groups, Examples thereof include a phosphino group, a phosphinyl group, a phosphinyloxy group, a phosphinylamino group, a silyl group, or a group containing a siloxane bond.
Substituents that may be present in the present invention include the monovalent substituents described above, and optionally an alkylene group, an alkenylene group, an arylene group, a heteroarylene group, an ether bond, an ester bond, a sulfide bond, a carbonyl group, It may be a monovalent group combining an imino group or a divalent linking group combining them.

In addition, a group having a carboxyl group or a sulfanyl group means, in addition to a carboxyl group and a sulfanyl group, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an amino group, a (poly ) containing organosiloxane groups or acyl groups. Here, in addition to a carboxyl group and a sulfanyl group, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a (poly)organosiloxane group, an acyl group or a nitro group having a carboxyl group or a sulfanyl group as a substituent is is synonymous with the group in general formulas (A) to (C) and (1) to (3).

Examples of alkyl groups having a carboxyl group or aryl groups having a carboxyl group include, for example, a 2-carboxylethyl group, a 2,2-dicarboxylethyl group, a 2-carboxylethenyl group, a 2-cyano- 2-carboxylethenyl group, 2-trifluoromethyl-2-carboxylethenyl group, 2-fluoro-2-carboxylethenyl group and the like.

Examples of the alkyl group having a sulfanyl group, the aryl group having a sulfanyl group, or the acyl group having a sulfanyl group include a [(3-sulfanylpropanoyl)oxy]ethyl group and a [(2-sulfanylacetyl)oxy]ethyl group. , 4-(sulfanylmethyl)phenyl group, [(3-sulfanylpropanoyl)oxy]propyl group, 3-sulfanyl[(3-sulfanylpropanoyl)oxy]ethyl group, or {[(2-sulfanylethoxy)propanoyl] oxy}ethyl group and the like.

It is preferable that the treatment agent in the present invention has one adsorption site from the viewpoint of suppression of viscosity increase due to cross-linking between semiconductor fine particles.
When the treating agent in the present invention has a carboxyl group, the group having the carboxyl group is preferably bonded to an aryl group or a carbon atom forming a multiple bond. Above all, in general formula (1), at least one of R ² and R ⁷ is preferably a carboxyl group, an aryl group having an alkyl group having a carboxyl group, or an aryl group having a carboxyl group. In general formula (2), at least one of R ¹³ , R ¹⁸ and R ²³ is preferably a carboxyl group, an alkyl group having a carboxyl group, or an aryl group having a carboxyl group. In general formula (3), at least one of R ²⁷ and R ³² is preferably a carboxyl group, an alkyl group having a carboxyl group, or an aryl group having a carboxyl group.

When the treating agent in the present invention has a sulfanyl group, the group having a sulfanyl group is preferably an alkyl group having a sulfanyl group as a substituent, from the viewpoint of the stability of the treating agent in air. Furthermore, from the viewpoint of solvent compatibility, a group having a sulfanyl group as a substituent and an ester bond is more preferable. Among them, in general formula (1), X ¹ is an alkyl group having a sulfanyl group, and R ¹ to R ⁸ each independently represent a hydrogen atom, an optionally substituted alkyl group, or a substituent. It is preferably an aryl group which may have or an alkoxy group which may have a substituent. In the general formula (2), any one of R ¹³ and R ¹⁸ is an alkyl group having a carboxyl group or an alkyl group having a sulfanyl group, and R ¹¹ , R ¹² , R ¹⁴ to R ¹⁷ and R ¹⁹ to R ²⁵ are Each independently is preferably a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group or an optionally substituted alkoxy group. In general formula (3), X ² is an alkyl group having a sulfanyl group, and R ²⁶ to R ³⁵ each independently have a hydrogen atom, an optionally substituted alkyl group, or a substituent. It is preferably an aryl group which may be substituted or an alkoxy group which may have a substituent.

Specific examples of the treatment agent are shown below, but are not limited to these. In the following structural formula, when cis-type and trans-type geometric isomers exist, they may be cis-type or trans-type, or a mixture of cis-type and trans-type isomers. good too. The same applies to the syn-anti geometric isomerism.

<Quantum dot-containing composition>
The quantum dot-containing composition of the present invention contains the quantum dots described above and a solvent. The solvent that the quantum dot-containing composition may contain is to disperse the quantum dots and apply the quantum dot-containing composition of the present invention on a substrate such as a glass substrate so that the dry film thickness becomes a desired film thickness. Used for ease.

(solvent)
The solvent is not particularly limited, and examples include 1,2,3-trichloropropane, 1,3-butylene glycol, 1,3-butylene glycol diacetate, 1,4-dioxane, 2-heptanone, 2-methyl- 1,3-propanediol, 3,5,5-trimethyl-2-cyclohexen-1-one, 3,3,5-trimethylcyclohexanone, ethyl 3-ethoxypropionate, 3-methyl-1,3-butanediol, 3-methoxy-3-methyl-1-butanol, 3-methoxy-3-methylbutyl acetate, 3-methoxybutanol, 3-methoxybutyl acetate, 4-heptanone, m-xylene, m-diethylbenzene, m-dichlorobenzene, N,N-dimethylacetamide, N,N-dimethylformamide, n-butyl alcohol, n-butylbenzene, n-propyl acetate, N-methylpyrrolidone, toluene, octane, nonane, hexane, o-xylene, o-chlorotoluene , o-diethylbenzene, o-dichlorobenzene, p-chlorotoluene, p-diethylbenzene, sec-butylbenzene, tert-butylbenzene, γ-butyrolactone, water, methanol, ethanol, isopropyl alcohol, tert-tert-butanol, isobutyl alcohol, isophorone, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monotertiary butyl ether, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, ethylene Glycol monopropyl ether, ethylene glycol monohexyl ether, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, diisobutyl ketone, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether Acetate, diethylene glycol monomethyl ether, cyclohexanol, cyclohexanol acetate, cyclohexanone, dipropylene glycol dimer Tyl ether, dipropylene glycol methyl ether acetate, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monomethyl ether, diacetone alcohol, triacetin, tripropylene glycol monobutyl ether, tripropylene glycol Monomethyl ether, propylene glycol diacetate, propylene glycol phenyl ether, propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether, propylene glycol monopropyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether propionate, benzyl alcohol, methyl isobutyl ketone, methylcyclohexanol, n-amyl acetate, n-butyl acetate, isoamyl acetate, isobutyl acetate, propyl acetate, and dibasic acid esters.
These solvents can be used singly or as a mixture of two or more at an arbitrary ratio as required.

<Inkjet ink>
The composition containing the quantum dots of the present invention can also be used as an inkjet ink by adjusting the viscosity using a solvent, a resin component or a polymerizable monomer described below, or the like. When used as an inkjet ink, it is preferable to adjust the viscosity at 25° C. to 3 to 50 mPa·s.

In the case of inkjet ink, the solvent is selected from the viewpoint of solubility in resin, swelling effect on device members, viscosity, and ink drying property in the nozzle, and the following solvents (A-1) and (A-2) and (A-3) and having a boiling point of 135° C. or higher at 760 mmHg.
Solvent (A-1): R ³⁶ —(O—C ₂ H ₄ )m—O—C(=O)—CH ₃
[where R ³⁶ is an alkyl group having 1 to 8 carbon atoms, C ₂ H ₄ is a linear or branched ethylene chain, and 1≦m≦3. ]
Solvent ₍ A-2): ^R37- ( _OC3H6 )p-OC(=O) _-CH3
[where R ³⁷ is an alkyl group having 1 to 8 carbon atoms, C ₃ H ₆ is a linear or branched propylene chain, and 1≦p≦3. ]
Solvent (A-3): Organic solvent having two or more acetate structures

Specific examples of the solvents (A-1) to (A-3) include propylene glycol methyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, dipropylene glycol methyl ether acetate, propylene glycol diacetate, 1, Examples include 3-butylene glycol diacetate, 1,6-hexanediol diacetate, triacetin, etc., but are not necessarily limited thereto. Among them, diethylene glycol monoethyl ether acetate, dipropylene glycol methyl ether acetate, propylene glycol methyl ether acetate, and 1,3-butylene glycol diacetate are preferred from the viewpoint of ejection stability.
More preferably, the content of the solvent having a boiling point of 135° C. or higher at 760 mmHg is 60% by mass or more in the total solvent, from the viewpoint of ejection stability and ink drying property in nozzles.

Further, the inkjet ink can be added with a resin, a cross-linking agent, a polymerizable monomer, a photo-sensitive substance, or a heat-sensitive substance depending on the physical properties required for the printed matter. The amount of additive substances such as resins, cross-linking agents, polymerizable monomers, photosensitive substances, and heat-sensitive substances is 0 to 0 per part by mass of quantum dots, depending on the desired quantum dot concentration. 100 parts by mass can be added. If the amount exceeds 100 parts by mass, the quantum dot content may become low, and sufficient fluorescence intensity may not be obtained.

When the composition containing the quantum dots of the present invention is applied and patterned by photolithography by ultraviolet irradiation, a photosensitive substance and a polymerizable monomer are added to form a positive resist or a negative film. It can be a mold resist. These additive substances can be used alone or in combination of two or more.

(resin)
As the resin, either thermoplastic resin or thermosetting resin can be used, and petroleum resin, maleic acid resin, nitrocellulose, cellulose acetate butyrate, cyclized rubber, chlorinated rubber, alkyd resin, acrylic resin, polyester. Resins, amino resins, vinyl resins, butyral resins, and the like can be mentioned, and can be appropriately selected depending on the base material.

(crosslinking agent)
Cross-linking agents include melamine compounds, benzoguanamine compounds, acrylate monomers, carbodiimide compounds, epoxy compounds, oxetane compounds, phenol compounds, benzoxazine compounds, blocked carboxylic acid compounds, blocked isocyanate compounds, and silane coupling agents. One or two or more compounds selected from the group consisting of are preferable from the viewpoint of being a heat-crosslinking cross-linking agent having heat resistance.

(Polymerizable monomer)
Polymerizable monomers include monomers or oligomers that form resins by curing with ultraviolet light, heat, or the like, and these can be used alone or in combination of two or more.
Examples of polymerizable monomers include methyl (meth) acrylate, ethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, cyclohexyl (meth) acrylate, β-carboxyethyl (meth)acrylate, polyethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, glycerin di(meth)acrylate, triethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, Neopentyl glycol-modified trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, 1,6-hexanediol diglycidyl ether di(meth)acrylate ) acrylate, bisphenol A diglycidyl ether di(meth)acrylate, neopentyl glycol diglycidyl ether di(meth)acrylate, dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, tricyclodecanyl Various acrylates and methacrylates such as (meth)acrylates, ester acrylates, methylolated melamine (meth)acrylates, epoxy (meth)acrylates, urethane acrylates, (meth)acrylic acid, styrene, vinyl acetate, hydroxyl Ethyl vinyl ether, ethylene glycol divinyl ether, pentaerythritol trivinyl ether, (meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-vinylformamide, acrylonitrile and the like can be mentioned, but are not necessarily limited to these. .
These polymerizable compounds can be used singly or as a mixture of two or more at an arbitrary ratio as required.

(Thermal Sensitive Substance, Photosensitive Substance)
Examples of heat-sensitive substances include thermal polymerization initiators such as organic peroxide initiators and azo initiators. Moreover, a photopolymerization initiator, a photoacid generator, and a photobase generator are mentioned as a photosensitive substance. These can be used singly or as a mixture of two or more at any ratio as required.

(Photopolymerization initiator, photoacid generator)
Photopolymerization initiators include acetophenone compounds, benzoin compounds, benzophenone compounds, thioxanthone compounds, triazine compounds, oxime ester compounds, phosphine compounds, quinone compounds, borate compounds; carbazole compounds;
imidazole-based compounds; or titanocene-based compounds and the like are used.
Photoacid generators include sulfonium salts, tetrahydrothiophenium salts, N-sulfonyloxyimide compounds and the like.

The amount of the photopolymerization initiator and/or photoacid generator is preferably 0.01 to 20 parts per 100 parts of the polymerizable monomer. If the amount is less than 0.01 part, curing is insufficient, and if the amount is more than 20 parts, coloration derived from the photoacid generator and deterioration of other physical properties are caused.

(Photobase generator)
Photobase generators include heterocyclic group-containing photobase generators, 2-nitrobenzylcyclohexylcarbamate, [[(2,6-dinitrobenzyl)oxy]carbonyl]cyclohexylamine, bis[[(2-nitrobenzyl)oxy ]Carbonyl]hexane-1,6-diamine, triphenylmethanol, o-carbamoylhydroxylamide, o-carbamoyloxime, hexaamminecobalt (III) tris(triphenylmethylborate) and the like.

(sensitizer)
Additionally, the composition of the present invention may contain a sensitizer.
Sensitizers include chalcone derivatives, unsaturated ketones such as dibenzalacetone, 1,2-diketone derivatives such as benzyl and camphorquinone, benzoin derivatives, fluorene derivatives, naphthoquinone derivatives, and anthraquinone derivatives. , xanthene derivatives, thioxanthene derivatives, xanthone derivatives, thioxanthone derivatives, coumarin derivatives, ketocoumarin derivatives, cyanine derivatives, merocyanine derivatives, polymethine dyes such as oxonol derivatives, acridine derivatives, azine derivatives, thiazine derivatives, oxazine derivatives, indoline derivatives, Azulene derivatives, azulenium derivatives, squarylium derivatives, porphyrin derivatives, tetraphenylporphyrin derivatives, triarylmethane derivatives, tetrabenzoporphyrin derivatives, tetrapyrazinoporphyrazine derivatives, phthalocyanine derivatives, tetraazaporphyrazine derivatives, tetraquinoxalyloporphyrazine derivatives , naphthalocyanine derivatives, subphthalocyanine derivatives, pyrylium derivatives, thiopyrylium derivatives, tetraphylline derivatives, annulene derivatives, spiropyran derivatives, spirooxazine derivatives, thiospiropyran derivatives, metal arene complexes, organic ruthenium complexes, or Michler ketone derivatives, α-acyloxyesters , acylphosphine oxide, methylphenylglyoxylate, benzyl, 9,10-phenanthrenequinone, camphorquinone, ethylanthraquinone, 4,4′-diethylisophthalophenone, 3,3′, or 4,4′ -tetra(t-butylperoxycarbonyl)benzophenone, 4,4'-diethylaminobenzophenone and the like.
These sensitizers can be used singly or as a mixture of two or more at any ratio as required.

<Printed Matter>
A printed matter has a quantum dot-containing layer containing the quantum dots of the present invention on a substrate. The quantum dot-containing layer can be formed by the above-described quantum dot-containing composition or inkjet ink, and a method of forming a film by drying an organic solvent after coating and printing the composition or the like, or by ultraviolet irradiation. It can be formed by a method for forming a cured film.
The base material is not particularly limited, but plastic base materials such as polycarbonate, hard vinyl chloride, soft vinyl chloride, polystyrene, styrofoam, PMMA, polypropylene, polyethylene, PET, mixed or modified products thereof, fine paper, art paper, coated paper, Examples include paper substrates such as cast-coated paper, glass substrates, and metal substrates such as stainless steel.

<Light wavelength conversion layer>
A layer containing quantum dots of the present invention can be used as a light wavelength conversion layer. The light wavelength conversion layer is capable of converting excitation light into fluorescence on the long wavelength side and emitting it, and is not particularly limited as long as the relationship between the excitation light wavelength and the emission fluorescence wavelength can be maintained. is used as excitation light to obtain green or red fluorescence, and ultraviolet light or visible light is used as excitation light to obtain fluorescence in the near-infrared region.
The thickness of the light wavelength conversion layer is preferably 1 to 500 μm, more preferably 1 to 50 μm, still more preferably 1 to 10 μm. A thickness of 1 μm or more is preferable because a high wavelength conversion effect can be obtained. Moreover, when the thickness is 500 μm or less, the light source unit can be made thin when incorporated into the light source unit, which is preferable.

<Light wavelength conversion member>
A light wavelength conversion member can also be obtained by using the light wavelength conversion layer described above.
The light wavelength conversion member is a member in which the light wavelength conversion layer described above is formed on at least one side of a specific base material. The base material is not particularly limited, but plastic base materials such as polycarbonate, hard vinyl chloride, soft vinyl chloride, polystyrene, styrofoam, PMMA, polypropylene, polyethylene, PET, mixed or modified products thereof, fine paper, art paper, coated paper, Paper substrates such as cast-coated paper, glass, metal substrates such as stainless steel, and the like can be used.
The base material to be used is selected according to the application, but in the case of prepaid cards, transit cards, etc., plastic base materials and mixtures or modified products thereof are preferable from the viewpoint of durability. In the case of one-dimensional barcodes, two-dimensional barcodes, and QR codes (matrix two-dimensional codes) as information recording media, paper substrates are preferable in addition to plastic substrates. A transparent substrate is preferable for a wavelength conversion color filter.

<Light emitting element>
A layer containing quantum dots of the present invention can be used as a light-emitting layer in a light-emitting device. A light-emitting element has a substrate, a cathode and an anode provided on the substrate, a light-emitting layer between the electrodes, and a charge transport layer on at least one of the cathode and the anode. Furthermore, due to the nature of the light emitting device, at least one of the anode and cathode electrodes is transparent.
As a mode of lamination of the light-emitting element, a mode in which a hole-transporting layer, a light-emitting layer, and an electron-transporting layer are stacked in this order from the anode side is preferable. Furthermore, a charge blocking layer or the like may be provided between the hole-transporting layer and the light-emitting layer or between the light-emitting layer and the electron-transporting layer. A hole injection layer may be provided between the anode and the hole transport layer, and an electron injection layer may be provided between the cathode and the electron transport layer. Further, the light emitting layer may be a single layer, or the light emitting layer may be divided into a first light emitting layer, a second light emitting layer, a third light emitting layer, and the like. Further, each layer may be divided into multiple sublayers.

As a substrate for forming a light-emitting element, for example, a substrate used for a known organic EL element can be used. The substrate may be a resin film or a gas barrier film, such as JP-A-2004-136466, JP-A-2004-148566, JP-A-2005-246716, JP-A-2005-262529, etc. The gas barrier film described in 1. can also be preferably used.
Although the thickness of the substrate is not particularly specified, it is preferably 30 μm to 700 μm, more preferably 40 μm to 200 μm, still more preferably 50 μm to 150 μm. Furthermore, in any case, the haze is preferably 3% or less, more preferably 2% or less, still more preferably 1% or less, and the total light transmittance is preferably 70% or more, more preferably 80% or more, and still more preferably 90%. That's it.

<Anode>
The anode usually has a function as an electrode that supplies holes to an organic compound or inorganic compound layer, and its shape, structure, size, etc. are not particularly limited. Depending on the requirements, it can be appropriately selected from known electrode materials. As mentioned above, the anode is usually provided as a transparent anode. The transparent anode is described in detail in "New Development of Transparent Electrode Films" supervised by Yutaka Sawada, published by CMC (1999). When a plastic base material having low heat resistance is used as the substrate, a transparent anode formed by using ITO, IZO or IGZO at a low temperature of 150° C. or less is preferable.

<Cathode>
The cathode generally has a function as an electrode for injecting electrons into an organic compound or inorganic compound layer, and its shape, structure, size, etc. are not particularly limited. Accordingly, it can be appropriately selected from known electrode materials.
Materials constituting the cathode include, for example, metals, alloys, metal oxides, electrically conductive compounds, and mixtures thereof. Specific examples include group 2 metals (eg, Mg, Ca, etc.), gold, silver, lead, aluminum, lithium-aluminum alloys, magnesium-silver alloys, and rare earth metals such as indium and ytterbium. These may be used alone, but from the viewpoint of achieving both stability and electron injection properties, two or more of them can be preferably used in combination.

Among these materials, a material mainly composed of aluminum is preferable as the material constituting the cathode. The material mainly composed of aluminum refers to aluminum alone, and alloys of aluminum with 0.01 to 100% by mass of alkali metals or Group II metals (eg, lithium-aluminum alloy, magnesium-aluminum alloy, etc.). The materials for the cathode are described in detail in JP-A-2-15595 and JP-A-5-121172. In addition, a dielectric layer made of a fluoride, oxide, or the like of an alkali metal or group II metal may be inserted between the cathode and the organic compound or inorganic compound layer with a thickness of 0.1 to 5 nm. This dielectric layer can also be viewed as a kind of electron injection layer.

The thickness of the cathode can be appropriately selected depending on the material constituting the cathode, and cannot be defined unconditionally, but is usually about 10 nm to 5 μm, preferably 50 nm to 1 μm. Also, the cathode may be transparent or opaque. The transparent cathode can be formed by forming a thin film of a cathode material with a thickness of 1 to 10 nm and laminating a transparent conductive material such as ITO, IZO or IGZO.

<Light emitting layer>
When an electric field is applied, the light-emitting layer receives holes from the anode, the hole-injection layer, or the hole-transport layer, receives electrons from the cathode, the electron-injection layer, or the electron-transport layer, and forms a recombination field for the holes and electrons. It is a layer having a function of providing light to emit light. The light-emitting layer may be composed only of the quantum dots of the present invention, or may be composed of a mixed layer of quantum dots and a host material. The light-emitting material may further contain a fluorescent light-emitting material or a phosphorescent light-emitting material, and may contain one or more dopants. Preferably, the host material is a charge transport material. The number of host materials may be one or two or more, and examples thereof include a configuration in which an electron-transporting host material and a hole-transporting host material are mixed. Furthermore, the light-emitting layer may contain a material that does not have a charge-transporting property and does not emit light. Further, the light-emitting layer may be one layer or two or more layers, and each layer may emit light of a different color.

Examples of the fluorescent material include benzoxazole derivatives, benzimidazole derivatives, benzothiazole derivatives, styrylbenzene derivatives, polyphenyl derivatives, diphenylbutadiene derivatives, tetraphenylbutadiene derivatives, naphthalimide derivatives, coumarin derivatives, condensed aromatic compound, perinone derivative, oxadiazole derivative, oxazine derivative, aldazine derivative, pyraridine derivative, cyclopentadiene derivative, bisstyrylanthracene derivative, quinacridone derivative, pyrrolopyridine derivative, thiadiazolopyridine derivative, cyclopentadiene derivative, styrylamine derivative, di Various metal complexes such as ketopyrrolopyrrole derivatives, aromatic dimethylidine compounds, metal complexes of 8-quinolinol derivatives and metal complexes of pyrromethene derivatives, polymer compounds such as polythiophene, polyphenylene, and polyphenylene vinylene, compounds such as organic silane derivatives, etc. is mentioned.

Examples of the phosphorescent materials include complexes containing transition metal atoms or lanthanide atoms.
The transition metal atom is not particularly limited, but preferably includes ruthenium, rhodium, palladium, tungsten, rhenium, osmium, iridium and platinum, more preferably rhenium, iridium and platinum.
The lanthanide atoms include lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutecium. Among these lanthanide atoms, neodymium, europium and gadolinium are preferred.

As the ligand of the complex, for example, G. Wilkinson et al., Comprehensive Coordination Chemistry, Pergamon Press, 1987, H. Yersin, "Photochemistry and Photophysics of Coordination Compounds", Springer-Verlag, 1987, Akio Yamamoto Examples include ligands described in "Organometallic Chemistry - Fundamentals and Applications -" published by Shokabosha (1982).

Examples of the host material contained in the light-emitting layer include those having a carbazole skeleton, those having a diarylamine skeleton, those having a pyridine skeleton, those having a pyrazine skeleton, those having a triazine skeleton, and those having an arylsilane skeleton. and materials exemplified in the sections of the hole injection layer, the hole transport layer, the electron injection layer, and the electron transport layer described below.

<Hole injection layer, hole transport layer>
The hole injection layer and the hole transport layer are layers having a function of receiving holes from the anode or from the anode side and transporting them to the cathode side. It may be an organic compound or an inorganic compound, a low-molecular-weight compound, a high-molecular-weight compound, or a metal oxide, as long as it has the functions described above. Specifically, the hole injection layer and the hole transport layer include carbazole derivatives, triphenylamine derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylene diamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic tertiary amine compounds, styrylamine compounds, aromatic dimethylidine compounds, porphyrin compounds, Phthalocyanine compounds, low molecular compounds such as organic silane derivatives, carbon compounds such as carbon and fullerenes, inorganic compounds composed of metal oxides such as vanadium pentoxide and molybdenum trioxide, polyvinylcarbazole, polypyrrole, poly(3,4-ethylene) It is preferably a layer containing a polymer compound such as dioxythiophene)-poly(styrenesulfonic acid) (PEDOT-PSS).

<Electron injection layer, electron transport layer>
The electron injection layer and the electron transport layer are layers having a function of receiving electrons from the cathode or the cathode side and transporting them to the anode side. Specifically, the electron injection layer and the electron transport layer include triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, fluorenone derivatives, anthraquinodimethane derivatives, anthrone derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, Carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, aromatic ring tetracarboxylic acid anhydrides such as naphthalene and perylene, phthalocyanine derivatives, metal complexes of 8-quinolinol derivatives, metal phthalocyanine, benzoxazole and benzothiazole as ligands Various metal complexes represented by metal complexes, low-molecular-weight compounds such as organic silane derivatives, metal oxides such as zinc oxide (ZnO) and titanium oxide (TiO ₂ ), and organic or inorganic compounds doped with alkali metals. It is preferably a layer that

<Hole blocking layer>
The hole blocking layer is a layer having a function of preventing holes transported from the anode side to the light-emitting layer from passing through to the cathode side. In the present invention, a hole blocking layer can be provided as an organic compound layer adjacent to the light emitting layer on the cathode side. Further, the electron transport layer/electron injection layer may also function as a hole blocking layer.
Examples of the organic compound forming the hole blocking layer include aluminum complexes such as BAlq, triazole derivatives, phenanthroline derivatives such as BCP, and the like. Also, a layer having a function of preventing electrons transported from the cathode to the light-emitting layer from passing through to the anode can be provided at a position adjacent to the light-emitting layer on the anode side. The hole transport layer/hole injection layer may also serve this function.

<Light emitting device>
Also, the light wavelength conversion member and the light emitting element can be combined and used as a light emitting device. In the light emitting device, at least one of the light wavelength conversion layer of the light wavelength conversion member and the light emitting layer of the light emitting element may be formed using the ink composition of the present invention.
The light wavelength conversion member converts the excitation light into fluorescent light on the long wavelength side and emits it. It can be converted to fluorescence in the outer region. The light wavelength conversion member is not particularly limited as long as it maintains the relationship between the wavelength of the excitation light and the wavelength of the emitted fluorescence light, and an optimum one can be selected as appropriate.
In addition, as the light source of the conventionally known light emitting element, semiconductor light emitting elements such as light emitting diodes (LED) and semiconductor lasers (LD); organic electroluminescence (organic EL); or quantum dots can be used. .

EXAMPLES The present invention will be described in more detail with reference to examples below, but the examples below do not limit the scope of the present invention. "Parts" and "%" in the examples represent "mass parts" and "mass%".

<Production of resin>
[Preparation of resin solution 1]
70.0 parts of mesitylene was charged into a separable 4-necked flask equipped with a thermometer, a cooling tube, a nitrogen gas inlet tube, and a stirring device, and the temperature was raised to 80°C. A mixture of 18.0 parts of n-butyl methacrylate, 12.0 parts of methyl methacrylate and 0.4 parts of 2,2'-azobisisobutyronitrile was added dropwise over 2 hours. After the dropwise addition, the reaction was continued for 3 hours to obtain an acrylic resin solution having a mass average molecular weight (Mw) of 26,000. After cooling to room temperature, about 2 g of the resin solution was sampled and dried by heating at 180° C. for 20 minutes to measure the non-volatile content. to prepare an acrylic resin solution 1.

[Preparation of resin solution 2]
70.0 parts of diethylene glycol monobutyl ether acetate (DBCA) was charged into a reaction vessel equipped with a separable four-necked flask, a thermometer, a condenser, a nitrogen gas inlet tube, and a stirrer, and the temperature was raised to 80° C., and the inside of the reaction vessel was After purging with nitrogen, 2 parts of a mixture of 14.0 parts of n-butyl methacrylate, 10.0 parts of methyl methacrylate, 6.0 parts of styrene and 0.4 parts of 2,2'-azobisisobutyronitrile were added from the dropping tube. It dripped over time. After the dropwise addition, the reaction was continued for 3 hours to obtain an acrylic resin solution having a mass average molecular weight (Mw) of 26,000. After cooling to room temperature, about 2 g of the resin solution was sampled and dried by heating at 180 ° C. for 20 minutes to measure the non-volatile content. was added to prepare an acrylic resin solution 2.

[Preparation of resin solution 3]
200 parts of norbornene, 50 parts of cyclopentene, 180 parts of 1-hexene and 750 parts of toluene were placed in a reaction vessel purged with nitrogen and heated to 60°C. This was modified with 0.62 parts of a toluene solution of triethylaluminum (1.5 mol/l) and tert-C ₄ H ₅ OH/CH ₃ OH (tert-C ₄ H ₉ OH/CH ₃ OH/W=0 .35/0.3/1; molar ratio) added 3.7 parts of WCl ₆ solution (concentration 0.05 mol / l), heated and stirred at 80 ° C. for 3 hours, ring-opening polymerization reaction, hydrogenation reaction Then, trimethylbenzene was used to adjust the non-volatile content to 30% to obtain a cyclopentadiene resin solution 3.

<Production of quantum dot-containing composition>
[Comparative Example 1]
(Quantum dot R1-containing composition)
0.55 parts of anhydrous zinc acetate, 7.0 parts of dodecanethiol (treating agent R1), and 5.0 parts of oleylamine were heated and dissolved to prepare an additive solution. Next, 0.22 parts of indium chloride and 8.25 parts of octylamine were placed in a reactor and heated to 165° C. while bubbling with nitrogen. After dissolving the indium chloride, 0.86 parts of diethylaminophosphine was briefly injected and the temperature was controlled at 165° C. for 20 minutes. It was then quenched and cooled to 40°C.
The additive liquid was poured into the cooled solution, heated at 240° C. for 2 hours, and then allowed to cool to room temperature. After standing to cool, purification was performed by a reprecipitation method using hexane and ethanol to obtain quantum dots R1 in which core-shell type semiconductor fine particles having a core of InP and a shell of ZnS were surface-treated with dodecanethiol (treatment agent R1). . Furthermore, trimethylbenzene was used to adjust the solid content concentration to 10% to obtain a composition containing quantum dots R1.

[Example 1]
(Quantum dot 1-containing composition)
The quantum dots R1 obtained in Comparative Example 1 were diluted with toluene to a solid concentration of 1%. A toluene solution of the same amount of 5% treatment agent 1 was added and stirred for 12 hours. Purification was performed by a reprecipitation method using toluene and ethanol. Diethylene glycol monobutyl ether acetate was used to prepare a solid content concentration of 10%, and a composition containing quantum dots 1 in which core-shell type semiconductor fine particles having a core of InP and a shell of ZnS were surface-treated with a treatment agent 1 was obtained.

[Examples 2 to 21, Comparative Examples 2 to 4]
InP core was prepared in the same manner as in Example 1, except that the treatment agent was changed to treatment agents 2 to 21 and R2 to R4 shown in Tables 1 to 3, and the purification was performed using diethylene glycol monobutyl ether acetate and ethanol. A composition with a solid concentration of 10% containing quantum dots 2 to 21 and R2 to R4 obtained by surface-treating the core-shell type semiconductor fine particles whose shell is ZnS with the treatment agents shown in Tables 1 to 3 was obtained.

<Production of inkjet ink (IJ ink)>
[Examples 22 to 45, Comparative Examples 5 to 8]
A quantum dot-containing composition, a resin solution, and a solvent were blended in a sealable container according to the blending composition shown in Table 4. After that, the mixture was stirred in a sealed state, filtered using a membrane filter with a pore size of 1 μm, and inkjet inks 1 to 24 and inkjet inks R1 to R4 were prepared.

<Evaluation method for inkjet ink>
The following evaluations were performed on the resulting inkjet inks. Table 4 shows the results.

[Initial viscosity]
The initial viscosity of the inkjet ink was measured at 25° C. using a vibrating viscometer Viscomate VM-10A-L (manufactured by SEKONNIC).

[Viscosity stability]
After storing the inkjet ink for 7 days in an environment of 40° C., the viscosity was measured in the same manner as the initial viscosity evaluation, and the change rate was calculated by dividing the viscosity after time by the initial viscosity. If the change rate is less than 10%, ◎ (very good), 10% or more and less than 20% is ○ (good), 20% or more and less than 30% is △ (usable), and 30% or more is × (cannot be used). bottom. The rate of change should be less than 30%.

[Inkjet printability]
Inkjet printing was performed under the following printing conditions, and the case where the print pattern could be printed without any problem was rated as ◯ (usable), and the case where printing could not be performed due to ejection failure or the like was rated as x (unusable).
≪Inkjet printing conditions≫
Printer: Dimatix Materials Printer
Cartridges: 10 Dimatix Materials Cartridges, 10 pL
Print pattern: Circular pattern with a diameter of 9 mm Substrate: Round cover glass manufactured by Matsunami Glass Industry Temperature: 30°C
Drying after printing: 40°C for 20 minutes

[Quantum yield (QY) retention rate]
The quantum yield of fluorescence is measured under the following measurement conditions for the inkjet ink and the printed matter obtained in the above-described inkjet printability evaluation, and the quantum yield ratio of the printed matter is calculated when the quantum yield of the inkjet ink is set to 1. Quantum yield retention rate. The quantum yield retention ratio is preferably close to 1, and if it is 0.6 or more, it can be practically used.
◎: 0.8 ≤ QY retention rate (very good)
○: 0.7 ≤ QY retention rate < 0.8 (good)
△: 0.6 ≤ QY retention rate < 0.7 (usable)
×: QY maintenance rate < 0.6 (cannot be used)
≪Quantum yield measurement conditions≫
Measuring device Quantum efficiency measurement system QE-2000 manufactured by Otsuka Electronics Co., Ltd. Excitation wavelength 400 nm Integration range 375 to 425 nm
Fluorescence integration range 430-800 nm

Abbreviations in Table 4 are shown below.
DBCA: diethylene glycol monobutyl ether acetate

From the results in Table 4, the semiconductor fine particles were treated to have at least one partial structure selected from the group consisting of a carbazole skeleton, a diarylamine skeleton, a triarylamine skeleton, a quinoline skeleton and an indole skeleton, and at least one carboxyl group. It has been shown that the use of quantum dots surface-treated with a chemical agent can be used as an inkjet ink, has good viscosity stability, and can maintain an excellent fluorescence quantum yield even after printing. rice field.
Although the detailed mechanism of the above effects has not been clarified, the treatment agent specified in the present application having at least one partial structure selected from the group consisting of a carbazole skeleton, a triarylamine skeleton, a quinoline skeleton and an indole skeleton is an electron donating This is probably because the quantum dots have a structure in which the phenyl group is substituted with a phenyl group, which suppresses the aggregation of the quantum dots.

<Production of quantum dot-containing composition>
[Examples 46 to 66, Comparative Examples 9 to 12]
A quantum dot-containing composition and a solvent were blended in a sealable container according to the formulation shown in Table 5. After that, the mixture was sealed and stirred, and filtered using a membrane filter with a pore size of 1 μm to prepare quantum dot-containing compositions 1 to 21 and quantum dot-containing compositions R1 to R4.

<Evaluation of quantum dot-containing composition>
The following evaluation was performed about the obtained quantum dot containing composition. Table 5 shows the results.

[Sedimentation stability]
Sedimentation stability was evaluated according to the following criteria by visually observing the appearance after storing the quantum dot-containing composition for 7 days in a 40° C. environment.
◎: No sediment and turbidity (very good),
○: No sediment, very thin turbidity (good),
△: No sediment, cloudy (can be used)
×: Precipitation (unusable)

From the results in Table 5, the semiconductor fine particles have at least one partial structure selected from the group consisting of a carbazole skeleton, a diarylamine skeleton, a triarylamine skeleton, a quinoline skeleton and an indole skeleton, and a group consisting of a carboxyl group and a sulfanyl group. A composition using quantum dots surface-treated with a treatment agent having at least one selected adsorption site has excellent sedimentation stability of quantum dots and can be used stably over a long period of time.
When the treatment agent has a triphenylamine skeleton, it preferably has one carboxyl group or sulfanyl group as an adsorption site from the viewpoint of sedimentation stability, more preferably the carboxyl group is directly bonded to the aromatic ring. or a treating agent in which a sulfanyl group is bonded to an aromatic ring via an alkylene group. Furthermore, it is particularly preferable that the substituent that the triphenylamine skeleton may have is a hydrogen atom, an unsubstituted alkyl group, or an unsubstituted alkoxy group.
When the treating agent has a carbazole skeleton or a diphenylamine skeleton, a treating agent in which X ¹ or X ³ is a group having a sulfanyl group is preferable from the viewpoint of sedimentation stability. More preferably, the group having a sulfanyl group has an alkylene group and an ester bond.
Although the mechanism of action has not been clarified, it is thought that one adsorption site per molecule of the treatment agent is preferable so that there is no possibility of aggregation due to pseudo-crosslinking between quantum dots. It is presumed that good results were obtained when there was a significant interaction and a good combination was obtained.

Claims (7)

Quantum dots in which semiconductor fine particles are surface-treated with a treating agent represented by the following general formula (1), general formula (2), or general formula (3) .
General formula (1)

[In general formula (1),
X ¹ is a hydrogen atom, an optionally substituted alkyl group or an optionally substituted acyl group,
R ¹ to R ⁸ each independently represent a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted alkoxy group, or a substituent An aryloxy group which may have a substituent, an acyl group which may have a substituent, an amino group which may have a substituent, a (poly)organosiloxane group which may have a substituent, a carboxyl group or a sulfanyl group,
At least one of X ¹ and R ¹ to R ⁸ is a group having a carboxyl group, or X ¹ is an alkyl group having a sulfanyl group and an ester bond. ]

general formula (2)

[In general formula (2),
at least one of R 13 , R 18 and R 23 is each independently a carboxyl group or an alkyl group having a carboxyl group, or a sulfanyl group or an alkyl group ^having a ^sulfanyl group ^;
When at least one of R ¹³ , R ¹⁸ and R ²³ is a carboxyl group or an alkyl group having a carboxyl group, R ¹¹ to R ²⁵ each independently have a hydrogen atom or a substituent. optionally substituted alkyl group, optionally substituted alkoxy group, optionally substituted aryloxy group, optionally substituted acyl group, optionally substituted amino a group, a carboxyl group or a sulfanyl group,
When at least one of R ¹³ , R ¹⁸ and R ²³ is a sulfanyl group or an alkyl group having a sulfanyl group, R ¹¹ to R ²⁵ each independently have a hydrogen atom or a substituent. and an alkoxy group which may have a substituent. ]

General formula (3)

[In general formula (3),
X ² is a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group (excluding a phenyl group), or an optionally substituted acyl group,
R ²⁶ to R ³⁵ each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted alkoxy group, or a substituent An aryloxy group which may have a substituent, a (poly)organosiloxane group which may have a substituent, an amino group which may have a substituent, an acyl group which may have a substituent, a carboxyl group or It is a sulfanyl group, and at least one of X ² and R ²⁶ to R ³⁵ is a group having a carboxyl group or a group having a sulfanyl group. ] 2. The quantum dot according to claim 1, wherein the semiconductor fine particles are compound semiconductors. 3. The quantum dot according to claim 1 , wherein the semiconductor fine particle is core-shell type. A quantum dot-containing composition comprising the quantum dots according to any one of claims 1 to 3 and a solvent. An inkjet ink containing the quantum dot-containing composition according to claim 4 and having a viscosity of 3 to 50 mPa·s. A printed matter formed by the quantum dot-containing composition according to claim 4 or the inkjet ink according to claim 6. A light-emitting device having an anode, a light-emitting layer and a cathode on a substrate, wherein the light-emitting layer contains the quantum dots according to any one of claims 1 to 3 .