JP6969351B2 - Semiconductor fine particle compositions, quantum dots, coating liquids containing them, ink compositions, and their uses. - Google Patents

Description

The present invention relates to semiconductor fine particle compositions and quantum dots, coating liquids and ink compositions containing them, inkjet inks, coating materials and printed materials using them, wavelength conversion films, color filters, and light emitting elements.

Quantum dots, which are the main constituents of the present invention, are extremely small particles (dots) formed to confine electrons in a minute space in order to exhibit unique optical properties according to quantum mechanics. The size of one quantum dot is from 1 nanometer to several tens of nanometers in diameter, and is composed of about 10,000 or less atoms. In recent years, attention has been focused on the fact that the wavelength of the emitted fluorescence can be continuously controlled by the grain size and that sharp emission with high symmetry in the wavelength distribution of the fluorescence intensity can be obtained.
Quantum dots can be adjusted for fluorescence to a wavelength that easily penetrates the human body and can be delivered to any location in the body, so they are used for bioimaging as a light emitting material (Non-Patent Document 1), and as a wavelength conversion material without the risk of fading (solar cell applications). Patent Document 1), a clear light emitting material, and a wavelength conversion material are being studied for development in electronics and photonics applications (Patent Documents 2 and 3).

When developing for these applications, it is necessary to form fine patterns. A method of preparing a resist solution using a photosensitive material for pattern formation and irradiating it with light through a mask has been proposed (Patent Document 4). However, there are problems that the quantum dots are deteriorated when the photosensitive material or light is irradiated, and the quantum dots are also contained in the portion removed by development, and the utilization efficiency of the quantum dot material is poor.
The inkjet method is known as a method of not resisting. So far, quantum dot inks that can be used in the inkjet method have not been produced.

Japanese Unexamined Patent Publication No. 2006-216560 Japanese Unexamined Patent Publication No. 2008-11254 Japanese Unexamined Patent Publication No. 2009-251129 Japanese Unexamined Patent Publication No. 2015-127733

Kamitaka, "Semiconductor Quantum Dots, Their Synthesis Methods and Applications to Life Sciences", Production and Technology, Vol. 63, No. 2, 2011, p58-p65 Journal of the American chemical society 2007 129 15432-15433

An object of the present invention is to provide a coating liquid or an ink, particularly an ink that can be printed by an inkjet method, without impairing various characteristics of the semiconductor fine particle composition, particularly the fluorescence characteristics of quantum dots, and the use thereof is used. Further, it is an object of the present invention to provide a coated or printed matter having excellent characteristics and stability over time, more specifically, a wavelength conversion film, a color filter and a light emitting element having excellent fluorescence characteristics.

As a result of diligent studies to solve the above problems, the present inventor has made a semiconductor fine particle composition having a specific composition, so that the coating liquid and ink, particularly inkjet, without impairing various properties such as quantum dots. It is possible to produce inks that can be printed by the method, and to provide the coated matter and printed matter using them, particularly the printed matter by the ink jet method, and the wavelength conversion film, the color filter, and the light emitting element using them. I found it.

That is, the present invention relates to a semiconductor fine particle composition comprising a semiconductor fine particle (A) having a core / shell structure, fine particles (B) consisting only of compounds constituting the shell, and a solvent.

Further, in the present invention, the weight ratio of the semiconductor fine particles (A) having the core / shell structure to the fine particles (B) composed only of the compounds constituting the shell is 1:99 to 99: 1. The present invention relates to the above-mentioned semiconductor fine particle composition.

The present invention also relates to the semiconductor fine particle composition, wherein the fine particles (B) composed of only the compounds constituting the shell contain ZnS particles.

The present invention also relates to the semiconductor fine particle composition, wherein the semiconductor fine particles (A) having a core / shell structure are quantum dots.

The present invention also relates to the above-mentioned semiconductor fine particle composition, which further contains a resin.

The present invention also relates to a coating liquid containing the semiconductor fine particle composition.

The present invention also relates to a coated product using the coating liquid.

The present invention also relates to an ink composition comprising the semiconductor fine particle composition.

The present invention also relates to an inkjet ink containing the ink composition.

The present invention also relates to a printed matter made by using the ink composition.

The present invention also relates to a wavelength conversion film formed by using the coating liquid or the ink composition.

The present invention also relates to a color filter formed by using the coating liquid or the ink composition.

The present invention also relates to a light emitting device in which the light emitting layer is formed by using the coating liquid or the ink composition.

INDUSTRIAL APPLICABILITY The present invention provides a coating liquid or an ink, particularly an ink that can be printed by an inkjet method, without impairing various characteristics of the semiconductor fine particle composition, particularly the fluorescence characteristics of quantum dots. Further, by using it, a coated or printed matter having excellent characteristics and stability over time, more specifically, a wavelength conversion film, a color filter and a light emitting element having excellent fluorescence characteristics are provided.

Hereinafter, the present invention will be described in detail.

<Semiconductor fine particle composition and quantum dots>
The quantum dots constituting the main constitution of the present invention are compositions composed of specific semiconductor fine particles, and the semiconductor fine particles are semiconductors containing an inorganic substance as a component.
(Semiconductor fine particles (A))
The semiconductor fine particles of the present invention have a core / shell structure.
The semiconductor of the present invention is a single element selected from the group of elements represented by Group 2 elements, Group 10 elements, Group 11 elements, Group 12 elements, Group 13 elements, Group 14 elements, Group 15 elements and Group 16 elements, or 2 It is a semiconductor made of a compound containing more than one kind of element. Specifically, Si, Ge, Sn, Se, Te, B, C (including diamond), P, Co, Au, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdSeZn, CdTe, HgS, HgSe, HgSe BeSe, BeTe, MgS, MgSe, GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si 3 N 4, Ge 3 N 4, Al 2 O 3 , (Al, Ga, In) ₂ (S, Se, Te) ₃ , Al ₂ CO ₃ and the appropriate combination of two or more such materials.
Of the above, a compound semiconductor is preferable. The compound semiconductor is at least two kinds selected from the element group represented by Zn, Cd, B, Al, Ga, In, C, Si, Ge, Sn, N, P, As, Sb, Pb, S, Se and Te. It is a semiconductor composed of a compound containing the above elements.
More preferably, it is selected from the group of elements represented by Zn, B, Al, Ga, In, C, Si, Ge, Sn, N, P, S and Te, excluding the elements that may be safe for humans. It is a semiconductor composed of a compound containing at least two kinds of elements. For applications that emit visible light, semiconductors containing In as a constituent element are more preferable because of the narrow bandgap.

Of these, the core / shell type semiconductor fine particles (A) preferably used in the present invention have a structure in which the core structure is covered with a semiconductor component different from the semiconductor component forming the core. Since the outside is a semiconductor with a large bunt gap, excitons (electron-hole pairs) generated by energy excitation such as light are confined in 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 characteristics of the semiconductor quantum dots are improved. When used as quantum dots, suitable combinations of materials satisfying the above conditions include CdSe / ZnS, CdSe / ZnSe, CdS / ZnS, CdSe / CdS, CdTe / CdS, InP / ZnS, PbSe / PbS, and the like. Examples thereof include GaP / ZnS, Si / ZnS, InN / GaN, InP / CdSSe, InP / ZnSeTe, InGaP / ZnSe, InGaP / ZnS, Si / AlP, InP / ZnSTe, InGaP / ZnSTe, and InGaP / ZnSSe.
Further, ZnS, CdS, ZnSe and the like are often used as the shell component of the fine particles (A), but among them, when the core component of the fine particles (A) is a semiconductor fine particle containing In as a constituent element, ZnS is elementally toxic. However, it is particularly excellent in characteristics such as exciton confinement as a quantum dot, and is preferably used.

The average particle size of the inorganic material portion of the semiconductor fine particles (A) of the present invention is preferably 0.5 nm to 100 nm, and a particle size that gives desired characteristics can be selected. In the case of the core-shell type, a plurality of shell fine particles may be contained in one semiconductor fine particle. 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 to 10 nm. It is difficult to synthesize an average particle size of less than 0.5 nm, and in the case of quantum dots, if it exceeds 10 nm, the quantum confinement effect cannot be obtained and the desired fluorescence cannot be obtained. The feature of quantum dots is that the fluorescence wavelength can be arbitrarily changed by changing the core particle size even if the same material is used, and the particle size is set according to the desired fluorescence wavelength. The average thickness of the shell corresponds to the difference between the particle radius of the inorganic material part and the core particle radius. In the case of quantum dots, it is difficult to excite the core depending on the excitation method. Further, the average particle size of the entire fine particles including the coating material is preferably 2 nm to 1 μm. The shape of the semiconductor fine particles (A) is not limited to a spherical shape, and may be a rod shape, a disk shape, or any other shape.

(Particles (B))
Further, the semiconductor fine particle composition of the present invention is characterized by containing fine particles (B) composed of only compounds constituting the shell of the core / shell type semiconductor fine particles (A). Here, it is assumed that the composition of the fine particles (B) composed of only the compounds constituting the shell of the semiconductor fine particles (A) does not contain the ligand described later. This is because the ligand is adsorbed and may be attached or detached.
In the semiconductor fine particle composition, inorganic particles or a resin may be used in order to improve the dispersion stability of the coating liquid or ink, and the environmental resistance and stability of the coated matter or printed matter using them. However, since the characteristics of the semiconductor fine particles may be adversely affected, it is necessary to limit the types or limit the amount to the minimum necessary.
Here, if the fine particles (B) are made of the same compound as the compound constituting the shell of the semiconductor fine particles, these adverse effects are significantly reduced, so that the semiconductor fine particle composition is maintained while maintaining the characteristics of the semiconductor fine particles. It is possible to improve the dispersion stability of coating liquids and inks of materials, and the environmental resistance and stability of coated materials and printed materials using them.

As the component of the fine particles (B), ZnS, CdS, ZnSe and the like are preferably used as in the shell component of the fine particles (A) described above, and among these, ZnS is preferable because it has no elemental toxicity.

The average particle size of the inorganic material portion of the fine particles (B) of the present invention is preferably 0.5 nm to 100 nm, and the average particle size of the entire fine particles including the coating material is preferably 2 nm to 1 μm. As with the fine particles (A), if they are too small, they are difficult to synthesize, and if they are too large, the dispersion stability and environmental resistance after use may be impaired. The particle size ratio of the fine particles (B) / fine particles (A) is not particularly specified, but considering that the radius ratio to be inserted into the gap of the fine filling of the spherical particles is about 0.29, the coated material or When the final form of the printed matter is reached, in order to fill the particles uniformly as a whole, the fine particles (A) are finely divided between 0.25 to 4 in consideration of the shape of the particles and the particle size distribution. When you want to fill the filling gap with small diameter fine particles (B) and make it denser, 0.25 or less, and conversely, evenly arrange the fine particles (A) in the fine packing gap of the large diameter fine particles (B) to improve the characteristics. 4 or more is preferable for aiming. The shapes of the semiconductor fine particles (A) and / or (B) are not limited to spherical shapes, but may be rod-shaped, disk-shaped, or other shapes, in which case. The classification based on the particle size ratio will be different, and in that sense, it is just a guideline.

The weight ratio of the semiconductor fine particles (A) having a core / shell structure in the present invention to the fine particles (B) composed only of the compounds constituting the shell is preferably 1:99 to 99: 1. This ratio is determined by the balance between the good effect of the addition of the fine particles (B) due to the direct action of the fine particles (B), the adverse effect caused by the excessive addition, and the diluting effect of the fine particles (B) on the fine particles (A). NS. When the amount of the fine particles (B) added is 1 or less, no substantial effect is often seen. Further, since the excitation light absorption efficiency is often low in general quantum dots, it is not preferable to significantly reduce the weight ratio of the fine particles (A) when used in a wavelength conversion film or a color filter. However, in the case of a light emitting device, since a method other than photoexcitation is used, it is often preferable to significantly reduce the weight ratio of the fine particles (A) as in the case of so-called organic dopants. Further, in order to adjust the composition ratio of the semiconductor fine particles (A) in the final form of the coating liquid of the fine particles (A), the ink and the coated product, and the printed matter, an inorganic compound having a composition different from that of the fine particles (B) is further adjusted. Or, it does not prevent the addition of the resin.

The semiconductor fine particles (A) and the semiconductor fine particles (B) of the present invention may be further coated with an organic substance. These organic substances are often referred to as coating materials or protective materials, and are often referred to as treatment agents for the surface of fine particles during synthesis, and even in the case of quantum dots, ligands or ligands. Organic substances that can be generally used as a coating material have a strong polarity that adsorbs to the metal portion of the inorganic semiconductor fine particles, or an unshared electron pair, and further have a structure in which a carbon chain or an aromatic ring is linked, and a polyalkylene glycol. By having a structure or the like, it is an organic substance having a partial structure having a high affinity with a solvent or resin used as a coating liquid or an ink. Such organic substances are generally well known as dispersants for organic and inorganic pigments and inorganic compound materials, and surfactants and emulsifiers used in detergents and emulsion formation. These compounds can also be used in the invention. Further, a compound having a partial structure used as a ligand of a metal complex, particularly a compound having a chelate ligand structure having two or more coordination bonds to a metal, is adsorbed on the metal portion of the semiconductor fine particles. It is easy to use and difficult to remove, so it can be used.

In the present invention, the organic substance that can be used as a treatment agent at the time of synthesis is preferably an organic substance having an alkyl group having 8 or more carbon atoms as a partial structure, which has a high boiling point and can be expected to interact with an alkyl chain portion. Further, it may have a polar group in order to strengthen the action on the semiconductor fine particles, and examples of the organic substance that can be treated include organic acids, organic amines, sulfur-containing organic substances, and phosphorus-containing organic substances.

As the organic acid, a compound having a carboxylic acid at the terminal can be used, an aromatic ring and an ether group can be contained, and a plurality of carboxylic acids may be contained in the molecule. Specific examples include benzoic acid, biphenylcarboxylic acid, butylbenzoic acid, hexylbenzoic acid, cyclohexylbenzoic acid, naphthalenecarboxylic acid, hexanoic acid, heptanic acid, octanoic acid, ethylhexanoic acid, hexenoic acid, octenoic acid, citronellic acid, and sverin. Acids, ethylene glycol bis (4-carboxyphenyl) ether, (2-butoxyethoxy) acetic acid and the like can be mentioned.
The organic acid having an alkyl group having 8 or more carbon atoms as a partial structure is a compound having an alkyl group having 8 or more carbon atoms among the organic acids, and specifically, nonanoic acid, decanoic acid, lauric acid, and myristin. Examples thereof include acids, palmitic acid, stearic acid, trichosanoic acid, lignoseric acid, oleic acid, eicosazienoic acid, linolenic acid, sebacic acid, (2-octyloxy) acetic acid and the like.

As the organic amine, a compound having an amino group at the terminal can be used, and examples thereof include aromatic ring n-butylamine, iso-butylamine, tert-butylamine, n-hexylamine, n-heptylamine, and cyclohexylamine.
As an organic amine having an alkyl group having 8 or more carbon atoms as a partial structure,
Examples thereof include octylamine, dodecaamine, heptadecane-9-amine, N, N-dimethyl-n-octylamine and the like.

Examples of sulfur-containing organic substances include thiols and disulfides.
Thiols include allyl mercaptan, 1,3-benzenedimethanethiol, 2-amino-5-mercapto-1,3,4-thiadiazole, 3-amino-5-mercapto-1,2,4-triazolebutanethiol. , N-hexanethiol, n-heptanethiol, and the like.
Examples of sulfur-containing organic substances of thiols having an alkyl group having 8 or more carbon atoms as a partial structure include dodecanethiol, 1-docosanthiol, tert-dodecyl mercaptan and the like.
Examples of disulfides include bis (4-chloro-2-nitrophenyl) disulfide, hexyl sulfide, 3,3', 5,5'-tetrachlorodiphenyl disulfide and the like.
Examples of the sulfur-containing organic substances of sulfides having an alkyl group having 8 or more carbon atoms as a partial structure include dodecyl disulfide, octadecyl disulfide, and dodecyl octadecyl disulfide.

Examples of phosphorus-containing organic substances include butyl phosphate, hexyl phosphate, diisopropyl phosphate, mono-2-ethylhexyl phosphonate (2-ethylhexyl), propylphosphonic acid, hexylphosphonic acid, methyl hexylphosphonate, and hexyl isopropylphosphonate. can give.
Examples of phosphorus-containing organic substances having an alkyl group having 8 or more carbon atoms as a partial structure include octyl phosphate, didodecyl phosphate, dodecyl phosphate, dodecylphosphonic acid, dodecyl hexylphosphonate, decylphosphonic acid, and isopropyl decylphosphonate. Be done.

As a method for synthesizing the semiconductor fine particles (A) and / or (B) of the present invention, a method for producing in glass, a method for synthesizing in an aqueous solution, a method for synthesizing in an organic solvent, and the like are generally known. The method can be used. In particular, regarding InP / ZnS core-shell type quantum dots, the technical documents "Journal of American Chemical Society. 2007, 129, 15432-15433", "Journal of American Chemical Science. 2016, 138, 5923-59" Technical document "JournalofAmericanChemicalSociacy.2009,131,5691-5697" for quantum dots, technical document "ChemistryofMaterials.2009,21,242-2249" for Si quantum dots, technical document "JournalofAmelician. It can be synthesized by referring to the methods used.

As a method for producing the semiconductor fine particles (B) of the present invention, it may be synthesized by a method different from the shell forming process of the semiconductor fine particles (A), or it may be produced by a pulverization method using a massive compound or coarse particles as a raw material. It is preferable to synthesize the semiconductor fine particles (A) by the same method as the shell forming process because there are few differences in the type and amount of impurities mixed in and the physical properties of the produced particles. However, in order to surely obtain fine particles (B), fine adjustment of conditions such as temperature and time different from shell formation and addition of a new core component of crystal growth, that is, a composition different from that of the particles to be produced. In some cases, it may be necessary to add a nucleating agent or fine seed crystals having the same composition as the particles to be produced. By adding a nucleating agent and seed crystals, fine particles (A) and (B) can be simultaneously produced at a desired composition ratio.

In addition, the semiconductor fine particle composition that has already been surface-treated with the coating material and another coating material to be replaced are stirred in a solvent, or the semiconductor fine particle composition that has already been surface-treated with the coating material is roughly subjected to the solvent by centrifugal sedimentation or the like. After removal, the coating material of the semiconductor fine particles can be replaced, such as by redispersing the semiconductor nanoparticles in a solvent containing another coating material to be replaced, which is a desired solvent suitable for coating liquids and inks. By surface-treating a coating material having a high affinity with a resin or a resin, the final form of the desired coated or printed matter can be obtained.

When the semiconductor fine particles (A) of the present invention are quantum dots, the quantum dots in the coating liquid or the ink have a plurality of types having different particle sizes in order to obtain a plurality of emission peaks, such as red and green. Quantum dots can be mixed and used, and the ratio can be freely selected within the range of the content in the ink in total.

<Solvent and resin, additives>
The solvent used in the present invention includes toluene, 1,2,3-trichloropropane, 1,3-butylene glycol, 1,3-butylene glycol diacetate, 1,4-dioxane, 2-heptanone, and 2-methyl. -1,3-Propanediol, 3,5,5-trimethyl-2-cyclohexene-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, o-xylene, o-chlorotoluene, o-diethylbenzene, o- Dichlorobenzene, P-chlorotoluene, P-diethylbenzene, sec-butylbenzene, tert-butylbenzene, γ-butyrolactone, water, methanol, ethanol, isopropyl alcohol, tershal tarshalbutanol, 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 monotarsial 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, cyclo Hexanol, cyclohexanol acetate, cyclohexanone, dipropylene glycol dimethyl ether, dipropylene glyco Lumethyl 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 propio Nate, benzyl alcohol, methylisobutylketone, methylcyclohexanol, n-amyl acetate, n-butyl acetate, isoamyl acetate, isobutyl acetate, propyl acetate, dibasic acid ester and the like can be mentioned.
Of these, in order to print by the inkjet method, it is necessary to use a solvent having a boiling point of 120 ° C. or higher at normal pressure in order to prevent drying at the ejection head. An example of a solvent having a boiling point of 120 ° C. or higher at normal pressure is given. 1,4-Butanediol (228 ° C), 1,3-Butanediol (208 ° C), 2-ethyl-1-hexanol (185 ° C), benzyl alcohol (205 ° C), diisobutylketone (168 ° C), cyclohexanone (18 ° C) 156 ° C), diacetone alcohol (168 ° C), butyl acetate (121 ° C), methoxybutyl acetate (171 ° C), cellosolve acetate (156 ° C), propylene glycol monomethyl ether acetate (146 ° C), amyl acetate (130 ° C). , Methyl Lactate (145 ° C.) Ethyl Lactate (154 ° C.), Butyl Lactate (188 ° C.), Ethylene Glycol Monomethyl Ether Acetate (145 ° C.), Ethylene Glycol Monomethyl Ether (125 ° C.), Ethylene Glycol Monoethyl Ether (134 ° C.), Ethylene glycol monobutyl ether (171 ° C), ethylene glycol (197 ° C), propylene glycol (187 ° C), propylene glycol monomethyl ether (121 ° C), methoxymethylbutanol (173 ° C), diethylene glycol dimethyl ether (162 ° C), ethylene glycol diethyl Ether (121 ° C), perchloroethylene (121 ° C), dichlorobenzene (180 ° C), N-methyl-2-pyrrolidone (202 ° C), dimethylformamide (153 ° C), ethyl 3-ethoxypropionate (170 ° C) , Gamma-butyrolactone (203 ° C.), dimethylsulfoxyside (189 ° C.) and the like.
From the viewpoint of solubility, a hydrocarbon-based solvent having a boiling point of 120 ° C. or higher at normal pressure is preferable, and an aromatic hydrocarbon-based solvent having a boiling point of 120 ° C. or higher at normal pressure is particularly preferable.

Hydrocarbon solvents having a boiling point of 120 ° C or higher at normal pressure include octane (125 ° C), decane (174 ° C), 1-decene (171 ° C), decahydronaphthalene (191 ° C), and butylcyclohexane (180 ° C). , 2,3, -Dimethylheptane (140 ° C.) and the like.
Examples of the aromatic hydrocarbon solvent having a boiling point of 120 ° C. or higher at normal pressure include xylene (138 ° C.), mesitylene (164 ° C.), methylnaphthalene (245 ° C.), tert-butylbenzene (168 ° C.), and n-butylbenzene. (183 ° C) and the like.

Further, the inkjet ink of the present invention can also contain a solvent having a boiling point of less than 120 ° C. Solvents contained include methanol, ethanol, isopropyl alcohol, normal propyl alcohol, butanol, isobutanol, tertiary butanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, methyl acetate, normal propyl acetate, isopropyl acetate, 1,4. -Dioxane, methyl tertiary butyl ether, isopropyl ether), ethylene glycol dimethyl ether, methylene chloride, trichloroethylene, fluorocarbon, bromopropane, chloroform, tetrahydrofuran, dimethyl carbonate, diethyl carbonate, acetonitrile, 1,3-dioxolane and the like.
Solvents having a boiling point of less than 120 ° C. are preferably mixed in the range of 0 to 60% of the volatile content. If the content is higher than this, the ink dries quickly and it becomes difficult to eject the ink jet.

Examples of the resin include petroleum-based resin, maleic acid resin, nitrocellulose, cellulose acetate butyrate, cyclized rubber, rubber chloride, alkyd resin, acrylic resin, polyester resin, amino resin, vinyl resin, butyral resin and the like. It can be selected in a timely manner depending on the coating, printing method and base material. Further, as the resin that may be contained, a linear olefin resin, an aromatic polyether resin, a polyimide resin, a fluorene polycarbonate resin, a fluorene polyester resin, a polycarbonate resin, a polyamide (aramid) resin, and a polyarylate Resins, polysulfone resins, polyether sulfone resins, polyparaphenylene resins, polyamideimide resins, polyethylene naphthalate (PEN) resins, fluorinated aromatic polymer resins, (modified) acrylic resins, epoxy Examples thereof include based resins, allyl ester-based curable resins and silsesquioxane-based ultraviolet curable resins.

A surfactant may be added to the coating liquid and the ink of the present invention for the purpose of adjusting the surface tension and ensuring the wettability of the ink on the printing substrate. In the present invention, any cationic, anionic, amphoteric, or nonionic surfactant can be used.
Examples of the cationic surfactant include fatty acid amine salts, aliphatic quaternary ammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts, and imidazolinium salts.

Anionic surfactants include fatty acid soaps, N-acyl-N-methylglycine salts, N-acyl-N-methyl-β-alanine salts, N-acylglutamates, acylated peptides, alkylsulfonates, etc. Alkylbenzene sulphonate, alkylnaphthalen sulphonate, dialkyl sulfosuccinic acid ester salt, alkyl sulfoacetate salt, α-olefin sulfonate, N-acylmethyl taurine, sulfated oil, higher alcohol sulfate ester salt, secondary higher alcohol Examples thereof include sulfate ester salts, alkyl ether sulfate salts, secondary higher alcohol ethoxysulfates, fatty acid alkylolamide sulfate ester salts, alkyl ether phosphate ester salts, and alkyl phosphate ester salts.
Examples of the amphoteric tenside agent include carboxybetaine type, sulfobetaine type, aminocarboxylate, and imidazolinium betaine.
Examples of the nonionic surfactant include polyoxyethylene secondary alcohol ether, polyoxyethylene alkylphenyl ether, polyoxyethylene sterol ether, polyoxyethylene lanolin derivative polyoxyethylene polypropylene alkyl ether, polyoxyethylene glycerin fatty acid ester, and poly. Oxyethylene castor oil, hardened castor oil, polyoxyethylene sorbitol fatty acid ester, polyethylene glycol fatty acid ester, fatty acid monoglyceride, polyglycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, sucrose fatty acid ester, fatty acid alkanolamide, polyoxyethylene Examples thereof include fatty acid amide, polyoxyethylene alkylamine, alkylamine oxide, acetylene glycol, and acetylene alcohol.

Among the surfactants, it is preferable to use a surface tension adjusting agent in order to improve the wettability to the printing substrate, and specifically, acetylenediol-based, silicon-based, acrylic-based, and fluorine-based are preferable. .. The above-mentioned surfactant may be used alone or in combination of two or more.

As the coating liquid and ink of the present invention, various additives such as plasticizers, ultraviolet inhibitors, light stabilizers, antioxidants, and hydrolysis inhibitors can also be used.

<Printing method>
The coated matter and printed matter of the present invention can be obtained by forming or coating the coating liquid of the present invention on a substrate. Known wet film forming methods such as spin coating method, casting method, micro gravure coating method, gravure coating method, bar coating method, roll coating method, wire bar coating method, dip coating method, spray coating method, screen printing method, It can be produced by using a coating method such as a flexographic printing method, an offset printing method, an inkjet printing method, a capillary coating method, and a nozzle coating method.
Examples of the base material include a glass plate and a resin plate.

Of these, the inkjet printing method used in the present invention is a single-pass method in which inkjet ink is ejected to a recording medium only once for recording, and a method perpendicular to the transport direction of the recording medium between the maximum recording width of the recording medium. Any serial type method in which recording is performed while reciprocating scanning a short shuttle head in the direction may be adopted. Further, the inkjet recording device needs to include an inkjet head (ink ejection means) for ejecting inkjet ink and a drying step for drying the ink ejected from the inkjet head. When the ink is ejected from the inkjet head, the ejected ink lands on the printing substrate and an image is recorded, and the image is conveyed into the drying device as the printing substrate is conveyed and the drying process is performed. ..

The inkjet method is not particularly limited, and is known as a known method, for example, a charge control method for ejecting ink by using an electrostatic attraction, a drop-on-demand method (pressure pulse method) using the vibration pressure of a piezo element, or an electric signal. An acoustic inkjet method that converts the ink into an acoustic beam and irradiates the ink to eject the ink using radiation pressure, and a thermal inkjet method that heats the ink to form bubbles and uses the generated pressure (Bubble Jet (registered trademark)). Any method may be used.

The inkjet head used in the inkjet method may be an on-demand method or a continuous method. Further, as the discharge method, an electric-mechanical conversion method (eg, single cavity type, double cavity type, bender type, piston type, shared mode type, shared wall type, etc.), an electric-heat conversion method (eg, thermal inkjet). Specific examples include molds, bubble jet (registered trademark) types, electrostatic suction methods (eg, electrolytic control type, slit jet type, etc.), and discharge methods (eg, spark jet type, etc.). However, any discharge method may be used. The ink nozzle or the like used when recording by the inkjet method is not particularly limited, and can be appropriately selected according to the purpose.

As the amount of ink droplets ejected from the inkjet head, 0.2 to 20 picolitres (pL) are preferable, and 1 to 15 picolitres (pL) are preferable from the viewpoint of greatly reducing the drying load and improving image quality. Is more preferable.

The wavelength conversion film and color filter, which are the final forms of the present invention, are used for absorbing light from a light source and extracting light of a desired wavelength by transmitted light that has not been absorbed or fluorescence emission generated by light absorption. Is. In particular, when quantum dots are used in the present invention, fluorescence emission with an excellent quantum yield will be used. The wavelength conversion film of the present invention is a coating or printing film obtained by applying the coating liquid or the ink composition of the present invention to a substrate and containing quantum dots emitting fluorescent colors of green and red. It is a planar member that converts blue light of a light source into white light mainly in a display panel or lighting, or adjusts pseudo-white light having an unbalanced color tone to a desired color tone.

Further, the color filter of the present invention is a color filter obtained by forming at least one segment of a filter segment using the coating liquid or the ink composition of the present invention, and is particularly used for a liquid crystal display panel. Specifically, a fine striped filter segment having three or more different hues arranged in parallel or crossing each other on the surface of a transparent substrate such as glass, or a fine mosaic-like filter segment. It consists of those arranged in a constant vertical and horizontal arrangement. In the present invention, unlike the light absorption type color filter that extracts blue, green, and red light from a conventional white light source, green and red are extracted mainly by a blue LED or the like as a light source and a fluorescent filter. When quantum dots are used, energy loss is reduced because the fluorescence is extracted with high quantum yield instead of dimming due to light absorption, and the wavelength distribution is narrow and colors close to pure colors can be obtained, resulting in a highly efficient display. It can be manufactured.

In general, a color filter is often manufactured by a resist method of patterning exposure and removing unnecessary parts in development after producing a solid thin film, and it cannot be applied to the fine particle composition of the present invention. Although it is possible, it is advantageous to apply the inkjet method in the present invention from the viewpoint of productivity due to the difference in the number of processes and low cost of no material loss in the developing process.

Further, a light emitting device having a light emitting layer formed by using a coating liquid or an ink composition, which is one of the final forms of the present invention, will be described in detail.

The light emitting device in the present invention is generally referred to as an electroluminescent element, and is composed of an element in which a single layer or a multilayer organic layer is formed between an anode and a cathode. Here, the single-layer electroluminescent element is an anode. Refers to an element consisting only of an electroluminescent layer between the cathode and the light emitting layer. On the other hand, the multi-layer electroluminescent element facilitates the injection of holes and electrons into the light emitting layer in addition to the light emitting layer, and facilitates the recombination of holes and electrons in the light emitting layer. It refers to a stack of a hole injection layer, a hole transport layer, a hole blocking layer, an electron injection layer, and the like. Further, an interconnect layer that exists adjacent to the light emitting layer between the light emitting layer and the anode and has a role of separating the light emitting layer and the anode or the light emitting layer from the hole injection layer or the hole transport layer. Layers may be inserted. Therefore, typical element configurations of the multilayer electro-emitting element are (1) anode / hole injection layer / light emitting layer / cathode, and (2) anode / hole injection layer / hole transport layer / light emitting layer / cathode. , (3) anode / hole injection layer / light emitting layer / electron injection layer / cathode, (4) anode / hole injection layer / hole transport layer / light emitting layer / electron injection layer / cathode, (5) anode / positive Pore 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) Anodic / 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) Anodium / hole injection layer / interlayer layer / light emitting layer / electron injection layer / cathode, (11) anode / hole injection layer / hole transport layer / interlayer layer / light emitting layer / electron injection It is conceivable that the element structure is laminated with a multi-layer structure such as a layer / cathode.

Further, each of the above-mentioned layers may be formed by a layer structure of two or more layers, or several layers may be repeatedly laminated. As such an example, in recent years, for the purpose of improving the light extraction efficiency, an element configuration called "multi-photon emission" in which a part of the layers of the above-mentioned multi-layer electroluminescent element is multi-layered has been proposed. This is, for example, in an electroluminescent element composed of a glass substrate / anode / hole transport layer / electron transporting light emitting layer / electron injection layer / charge generating layer / light emitting unit / cathode. A method of laminating a plurality of layers of the portions can be mentioned.

For the hole injection layer, a hole injection material that exhibits an excellent hole injection effect on the light emitting layer and can form a hole injection layer having excellent adhesion to the anode interface and thin film forming property is used. Further, when such a material is laminated in multiple layers and a material having a high hole injection effect and a material having a high hole transport effect are laminated in multiple layers, the materials used for each are referred to as a hole injection material and a hole transport material. Sometimes. The material for an electroluminescent device of the present invention can be suitably used for both a hole injection material and a hole transport material. These hole injection materials and hole transport materials need to have a large hole mobility and a small ionization energy of usually 5.5 eV or less. As such a hole injection layer, a material that transports holes to the light emitting layer with a lower electric field strength is preferable, and further ^{, when an electric field with a hole mobility of, for example, 10 4} to 10 ⁶ V / cm is applied, at least. ^{It is preferably 10-6} cm ² / V · sec. The other hole injecting material and hole transporting material that can be mixed with the electroluminescent device material of the present invention are not particularly limited as long as they have the above-mentioned preferable properties. Any material can be selected and used from those commonly used as hole charge transport materials in transmission materials and known materials used for the hole injection layer of electroluminescent devices.

Specific examples of such hole injecting materials and hole transporting materials include triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, and arylamine derivatives. , Amino-substituted carcon derivatives, oxazole derivatives, styrylanthracene derivatives (, fluorenone derivatives, hydrazone derivatives, stilben derivatives, silazane derivatives, polysilane-based derivatives, aniline-based copolymers, conductive polymer oligomers (particularly thiophene oligomers), etc. Can be done.

Of these, porphyrin compounds, aromatic tertiary amine compounds and styrylamine compounds can also be used as suitable ones. For example, 4,4'-bis (N- (1-naphthyl) -N-phenylamino) biphenyl having two fused aromatic rings in the molecule, or three triphenylamine units linked in a starburst type. Examples thereof include 4,4', 4 "-tris (N- (3-methylphenyl) -N-phenylamino) triphenylamine, etc., and copper phthalocyanine, hydrogen phthalocyanine, etc. as the hole injection material. Further, phthalocyanine derivatives can also be mentioned. In addition, inorganic compounds such as aromatic dimethylidene compounds, p-type Si and p-type SiC can also be used as hole injection materials and hole transport materials.

Further, materials that can be used for the hole injection layer include molybdenum oxide (MnO _x ), vanadium oxide (VO _x ), ruthenium oxide (RuO _x ), copper oxide (CuO _x ), tungsten oxide (WO _x ), and iridium oxide. Inorganic oxides such as (IrO _x ) can also be mentioned.

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

Examples of the material used for the interlayer layer include polyvinylcarbazole and its derivatives, polyarylene derivatives having aromatic amines in the side chain or main chain, arylamine derivatives, and polymers containing aromatic amines such as triphenyldiamine derivatives. Further, as the film forming method of the interlayer layer, when a high molecular weight material is used, a method of forming a film from a solution is exemplified.

For the film formation of the interlayer layer from the solution, known wet film forming methods such as spin coating method, casting method, micro gravure coating method, gravure coating method, bar coating method, roll coating method, wire bar coating method, etc. A coating method such as a dip coating method, a spray coating method, a screen printing method, a flexo printing method, an offset printing method, an inkjet printing method, a capillary coating method, or a nozzle coating method can be used.

The optimum value of the thickness of the interlayer layer differs depending on the material used, and it may be selected so that the drive voltage and the luminous efficiency are appropriate values. Usually, it is 1 nm to 1 μm, preferably 2 to 500 nm. More preferably, it is 5 to 200 nm.

On the other hand, as the electron injection layer, an electron injection material that exhibits an excellent electron injection effect on the light emitting layer and can form an electron injection layer having excellent adhesion to the cathode interface and thin film forming property is used. Examples of such electron-injected materials include metal complex compounds, nitrogen-containing five-membered ring derivatives, fluorenone derivatives, anthraquinodimethane derivatives, diphenoquinone derivatives, thiopyrandioxide derivatives, perylenetetracarboxylic acid derivatives, fleolenilidenemethane. Examples thereof include derivatives, anthron derivatives, silol derivatives, triarylphosphin oxide derivatives, polyquinolin and its derivatives, polyquinoxalin and its derivatives, polyfluorene and its derivatives, calcium acetylacetonate, sodium acetate and the like. Inorganic / organic composite materials in which a metal such as cesium is doped with vasophenanthroline, and the proceedings of the 50th Joint Lecture Meeting on Applied Physics, No. BCP, TPP, T5MPyTZ, etc. described on page 3, 1402, published in 2003 are also given as examples of electron injection materials, but they can form a thin film necessary for device fabrication, inject electrons from the cathode, and transport electrons. As long as it is a material, it is not particularly limited to these.

Among the electron-injected materials, preferred examples include a metal complex compound, a nitrogen-containing five-membered ring derivative, a silol derivative, and a triarylphosphine oxide derivative. As a preferable metal complex compound that can be used in the present invention, a metal complex of 8-hydroxyquinoline or a derivative thereof is suitable. Specific examples of the metal complex of 8-hydroxyquinoline or a derivative thereof include tris (8-hydroxyquinolinate) aluminum, tris (2-methyl-8-hydroxyquinolinate) aluminum, and tris (4-methyl-8-). Hydroxyquinolinate) Aluminum, Tris (5-Methyl-8-Hydroxyquinolinate) Aluminum, Tris (5-phenyl-8-Hydroxyquinolinate) Aluminum, Bis (8-Hydroxyquinolinate) (1-naphtholat) ) Aluminum, bis (8-hydroxyquinolinate) (2-naphtholat) Aluminum, bis (8-hydroxyquinolinate) (phenorate) aluminum, bis (8-hydroxyquinolinate) (4-cyano-1-naphtholate) ) Aluminum, bis (4-methyl-8-hydroxyquinolinate) (1-naphtholate) aluminum, bis (5-methyl-8-hydroxyquinolinate) (2-naphtholate) aluminum, bis (5-phenyl-8) -Hydroxyquinolinate) (phenorate) aluminum, bis (5-cyano-8-hydroxyquinolinate) (4-cyano-1-naphtholate) aluminum, bis (8-hydroxyquinolinate) chloroaluminum, bis (8) -Aluminum complex compounds such as hydroxyquinolinate (o-cresolate) 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-hydroxyquinolinate) (2-naphtholate) gallium, bis (2-methyl-8-hydroxyquinolinate) (phenorate) 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) (phenorate) gallium, bis (2-methyl-5- Cyano-8-hydroxyquinolinate) (4-cyano-1-naphtholate) gallium, bis (2-methyl-8-hydroxyquinolinate) chlorogallium, bis (2-methyl-8-hydroxyquinolinate) ( In addition to gallium complex compounds such as o-cresolate) gallium, 8-hydroxyquinolinate lithium, bis (8-hydroxyquinolinate) copper, bis (8-hydroxyquinolinate) manganese, bis (10-hydroxybenzo [h] ] Kinolinate) Metal complex compounds such as berylium, bis (8-hydroxyquinolinate) zinc, and bis (10-hydroxybenzo [h] quinolinate) zinc can be mentioned.

Among the electron-injected materials that can be used in the present invention, preferred examples of the nitrogen-containing five-membered ring derivative include an oxadiazole derivative, a thiazole derivative, an oxadiazole derivative, a thiadiazole derivative, and a triazole derivative. , 5-bis (1-phenyl) -1,3,4-oxadiazole, 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-butyl Benzene], 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-phenylthiazolyl)] benzene, 2- (4'-tert-butylphenyl) -5- (4 "-biphenyl) -1,3,4-triazole, 2 , 5-Bis (1-naphthyl) -1,3,4-triazole, 1,4-Bis [2- (5-phenyltriazolyl)] benzene and the like can be mentioned.

Further, examples of the material that can be used for the electron injection layer include inorganic oxides such as _{zinc oxide (ZnO) and titanium oxide (TiO 2).}

Further, as the hole blocking layer, a hole blocking material that can prevent holes that have passed through the light emitting layer from reaching the electron injection layer and can form a layer having excellent thin film forming properties is used. Examples of such hole blocking materials include aluminum complex compounds such as bis (8-hydroxyquinolinate) (4-phenylphenanthrate) aluminum and bis (2-methyl-8-hydroxyquinolinate) ( Examples thereof 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 the light emitting layer of the electroluminescent element of the present invention, one having the following functions is suitable.
Injection function; A function that can inject holes from the anode or hole injection layer when an electric field is applied, and can inject electrons from the cathode or electron injection layer. Transport function; Electric charge (electrons and holes) injected Light emitting function; a function that provides a field for recombination of electrons and holes and connects them to light emission. However, there is a difference between the ease of hole injection and the ease of electron injection. Also, the transport capacity expressed by the mobility of holes and electrons may be large or small.

The light emitting layer formed by using the coating liquid or the ink composition of the present invention can be preferably used. In order to obtain a light emitting layer formed by using the coating liquid or ink composition of the present invention, the light emitting layer is formed by combining the coating liquid or ink composition of the present invention with other light emitting compounds. Can be done.

As a compound exhibiting blue to green light emission that may be added to the coating liquid or ink composition of the present invention in order to obtain a light emitting layer formed by using the coating liquid or ink composition of the present invention. Can be used as a fluorescent whitening agent such as benzothiazole-based, benzimidazole-based, benzoxazole-based, metal chelated oxynoid compound, and styrylbenzene-based compound.

Examples of the metal chelated oxinoid compound include 8-hydroxyquinoline-based metal complexes such as tris (8-quinolinol) aluminum and dilithium epintridione as suitable compounds.

Further, as the styrylbenzene compound, for example, a distyrylpyrazine derivative can also be used as a material for the light emitting layer. In addition, a polyphenyl compound may be added to the coating liquid or ink composition of the present invention.

Further, in addition to the above-mentioned fluorescent whitening agent, metal chelated oxynoid compound, styrylbenzene compound and the like, for example, 12-phthaloperinone, 1,4-diphenyl-1,3-butadiene, 1,1,4,4-tetraphenyl -1,3-butadiene, naphthalimide derivative, perylene derivative, oxadiazole derivative, aldazine derivative, pyrazirin derivative, cyclopentadiene derivative, pyrolopyrrole derivative, styrylamine derivative, coumarin compound, polymer compound, 9,9', Examples thereof include 10,10'-tetraphenyl-2,2'-biantrasen, PPV (polyparaphenylene vinylene) derivatives, polyfluorene derivatives and their copolymers. Further, with phenolic ligands such as bis (2-methyl-8-quinolinolate) (para-phenylphenolate) aluminum (III) and bis (2-methyl-8-quinolinolate) (1-naphtholate) aluminum (III), Examples thereof include metal complexes having a substituted 8-quinolinolate ligand at the same time.

The light emitting layer for obtaining white light emission is not particularly limited, but the following can be used. An electroluminescent laminated structure that defines the energy level of each layer and emits light by using tunnel injection (European Patent No. 0390551).
Similarly, an element using tunnel injection and a white light emitting element is described as an example (Japanese Patent Laid-Open No. 3-230584). A light emitting layer having a two-layer structure is described (Japanese Patent Laid-Open No. 2-220390 and JP-A-2-216790). A light emitting layer is divided into a plurality of layers and each is composed of a material having a different emission wavelength (Japanese Patent Laid-Open No. 4-51491). A structure in which a blue light emitter (fluorescence peak 380 to 480 nm) and a green light emitter (480 to 580 nm) are laminated and further contained a red phosphor (Japanese Patent Laid-Open 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 phosphor (Japanese Unexamined Patent Publication No. 7-142169).

Further, as the material used for the anode of the electroluminescent element of the present invention, a metal, an alloy, an electrically conductive compound or a mixture thereof having a large work function (4 eV or more) as an electrode material 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, these electrode materials can be formed into a thin film by a method such as a thin film deposition method or a sputtering method. When the light emitted from the light emitting layer is taken out from the anode, it is desirable that the anode has a property that the transmittance of the anode with respect to the light emitted is larger than 10%. Further, the sheet resistance of the anode is preferably several hundred Ω / □ or less. Further, the film thickness of the anode is usually selected in the range of 10 nm to 1 μm, preferably 10 to 200 nm, depending on the material.

Further, as the material used for the cathode of the electroluminescent element of the present invention, a metal having a small work function (4 eV or less), an alloy, an electrically conductive compound, or a mixture thereof is used as an electrode material. 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 metal and the like. This cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. Here, when the light emitted from the light emitting layer is taken out from the cathode, the transmittance of the cathode with respect to the light emitted is preferably larger than 10%. The sheet resistance of the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually 10 nm to 1 μm, preferably 50 to 200 nm.

Regarding the method for producing the electroluminescent device of the present invention, an anode, a light emitting layer, a hole injection layer if necessary, and an electron injection layer if necessary are formed by the above materials and methods, and finally a cathode is formed. do it. Further, the electroluminescent device can be manufactured from the cathode to the anode in the reverse order of the above.

This electroluminescent element is manufactured on a translucent substrate. This translucent substrate is a substrate that supports an electroluminescent element, and its translucency is preferably such that the transmittance of light in the visible region of 400 to 700 nm is 50% or more, preferably 90% or more. It is preferable to use a smoother substrate.

These substrates are not particularly limited as long as they have mechanical and thermal strength and are transparent, but for example, a glass plate, a synthetic resin plate, or the like is preferably used. Examples of the glass plate include plates formed of soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, quartz and the like. Examples of the synthetic resin plate include a plate such as a polycarbonate resin, an acrylic resin, a polyethylene terephthalate resin, a polyether sulfide resin, and a polysulfon resin.

As a method for forming each layer excluding the light emitting layer of the electroluminescent element of the present invention, a dry film forming method such as vacuum vapor deposition, electron beam irradiation, sputtering, plasma, ion plating, or spin coating, dipping, flow coating, etc. Any method of the wet film forming method can be applied. In addition, the special table 2002-543782 and S.A. T. Lee, et al. , Proceedings of SID'02, p. The LITI (Laser Induced Thermal Imaging) method described in 784 (2002), printing (offset printing, flexographic printing, gravure printing, screen printing), inkjet printing, and the like can also be applied.

The organic layer excluding the polymer material is particularly preferably a molecular deposition film. Here, the molecular deposition film is a thin film deposited and formed from a material compound in a gas phase state, or a film solidified and formed from a material compound in a solution state or a liquid phase state, and is usually this molecular deposition film. Can be classified from the thin film (molecular cumulative film) formed by the LB method by the difference in aggregate structure, higher-order structure, and the functional difference caused by the difference. Further, as disclosed in Japanese Patent Application Laid-Open No. 57-57181, a binder such as a resin and a material compound are dissolved in a solvent to form a solution, which is then thinned by a spin coating method 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, resulting in inefficiency. On the contrary, if the film thickness is too thin, pinholes, etc. Is generated, and it becomes difficult to obtain sufficient emission brightness even when an electric field is applied. Therefore, the film thickness of each layer is preferably in the range of 1 nm to 1 μm, but more preferably in the range of 10 nm to 0.2 μm.

Further, in order to improve the stability of the electroluminescent element with respect to temperature, humidity, atmosphere and the like, a protective layer may be provided on the surface of the element, or the entire element may be coated or sealed with a resin or the like. In particular, when coating or sealing the entire element, a photocurable resin that is cured by light is preferably 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 voltage value are not particularly limited as long as they do not destroy the element, but considering the power consumption and life of the element, it is desirable to efficiently emit light with as little electric energy as possible.

The method for driving the electroluminescent element 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 electroluminescent element of the present invention, it can be applied not only to a method of bottom emission in which light is extracted from the anode side but also to a method of top emission in which light is extracted from the cathode side. These methods and techniques are described in Junji Kido, "All about Electroluminescence", Nihon Jitsugyo Publishing Co., Ltd. (published in 2003).

The main method of the full colorization method of the electroluminescent element of the present invention includes a three-color painting method, a color conversion method, and a color filter method. Examples of the three-color painting method include a vapor deposition method using a shadow mask, an inkjet method, and a printing method. In addition, the special table 2002-543782 and S.A. T. Lee, et al. , Proceedings of SID'02, p. The laser thermal transfer method described in 784 (2002) (also referred to as Laser Induced Thermo Imaging, LITI method) can also be used. The color conversion method is a method of converting from blue to green and red having a longer wavelength than blue through a color conversion (CCM) layer in which a fluorescent dye is dispersed by using a light emitting layer that emits blue light. The color filter method uses an electroluminescent element that emits white light to extract light of the three primary colors through a color filter for liquid crystal. In addition to these three primary colors, some white light is extracted as it is and used for light emission. As a result, the luminous efficiency of the entire element can be increased.

Further, the electroluminescent device of the present invention may adopt a microcavity structure. This is because the electroluminescent element has a structure in which a light emitting layer is sandwiched between an anode and a 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 that positively utilizes the multiple interference effect and controls the emission wavelength extracted from the element by appropriately selecting the optical characteristics such as the rate and the film thickness of the organic layer sandwiched between them. .. This also makes it possible to improve the emission chromaticity. For the mechanism of this multiple interference effect, refer to J.M. AM-LCD Digital Papers by Yamada et al., OD-2, p. 77-80 (2002).

As described above, the electroluminescent element using the light emitting layer formed by using the coating liquid or the ink composition of the present invention can obtain long-term light emission with a low driving voltage. Therefore, this electroluminescent element can be used as a flat panel display such as a wall-mounted television or various flat light emitters, as well as a light source such as a copier or a printer, a light source such as a liquid crystal display or an instrument, a display board, an indicator lamp, or the like. Can be applied.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not particularly limited to the examples. In the examples, "parts" and "%" represent "parts by weight" and "% by weight".

<Semiconductor fine particles (quantum dots) synthesis>
QD: InP / ZnS core-shell quantum dots were synthesized as follows according to the description of the technical document "Inorganic Chemistry 2016, (17), pp8831-8386". In addition, fine particles (B) composed of only the compounds constituting the shell were also synthesized according to this shell partial synthesis process.

<Synthesis and adjustment of quantum dot dispersion liquid QD-1>
1.35 parts of indium acetate, 1.30 parts of zinc octanate, 4.65 parts of stearic acid, and 92.7 parts of 1-octadecene were placed in a flask and heated to 100 ° C. Then, it was distilled off under reduced pressure at that temperature. The inside of the flask was filled with argon gas and heated to 300 ° C. Separately, 23 parts of a hexane solution containing 1.16 parts of tris (trimethylsilyl) phosphine prepared in a waterless glove box was injected, reacted at 280 ° C. for 9 minutes, and rapidly cooled. 15 parts of this solution, 46 parts of 1-octadecene and 11.5 parts of oleylamine were placed in a flask, stirred for 15 minutes, and then 4.3 parts of zinc dibenzyldithiocarbamate was added. The inside of the reaction flask was replaced with argon, the temperature was raised to 170 ° C. in 45 minutes, and the temperature was kept at 170 ° C. for 2 hours. After cooling, acetone was added, and the mixture was separated by centrifugal sedimentation. The precipitated paste was dispersed in toluene, 3.7 parts of dodecanethiol was added as a treatment agent, the mixture was stirred at room temperature for 24 hours, concentrated under reduced pressure, acetone was added, and the paste was separated by centrifugation. It was dispersed in toluene again to prepare a solid content concentration of 10%, and a quantum dot dispersion liquid QD-1 surface-treated with dodecanethiol was obtained.

<Adjustment of quantum dot dispersion liquid QD-2>
The quantum dot dispersion QD-1 was diluted with toluene to a solid content concentration of 1%. The same amount of a toluene solution of 5% hexanethiol was added, and the mixture was stirred for 12 hours. Purification was performed by the reprecipitation method using hexane and ethanol. Using trimethylbenzene, the solid content concentration was adjusted to 10%, and the surface-treated quantum dot dispersion liquid QD-2 was obtained with hexanethiol.

<Synthesis and adjustment of fine particle (B) dispersion liquid NP-1>
60 parts of 1-octadecene and 11.5 parts of oleylamine were placed in a flask, stirred for 15 minutes, and then 4.3 parts of zinc dibenzyldithiocarbamate was added. The inside of the reaction flask was replaced with argon, the temperature was raised to 170 ° C. in 45 minutes, and the temperature was kept at 170 ° C. for 2 hours. After cooling, acetone was added, and the mixture was separated by centrifugal sedimentation. The precipitated paste was dispersed in toluene, 3.7 parts of dodecanethiol was added as a treatment agent, the mixture was stirred at room temperature for 24 hours, concentrated under reduced pressure, acetone was added, and the paste was separated by centrifugation. It was dispersed in toluene again to prepare a solid content concentration of 10%, and a fine particle dispersion NP-1 surface-treated with dodecanethiol was obtained.

<Preparation of fine particle (B) dispersion liquid NP-2>
The fine particle dispersion NP-1 was diluted with toluene to a solid content concentration of 1%. The same amount of a toluene solution of 5% hexanethiol was added, and the mixture was stirred for 12 hours. Purification was performed by the reprecipitation method using hexane and ethanol. Using trimethylbenzene, the solid content concentration was adjusted to 10%, and a fine particle dispersion NP-2 surface-treated with hexanethiol was obtained.

<Adjustment of resin solution 1>
Paraffin wax 155 (manufactured by Nippon Seiro) was dissolved in decan so as to have an NV of 10%.

<Adjustment of resin solution 2>
A reaction vessel equipped with a thermometer, a cooling tube, a nitrogen gas introduction tube, and a stirrer was charged with 70.0 parts of xylene in a separable 4-neck flask, the temperature was raised to 80 ° C., the inside of the reaction vessel was replaced with nitrogen, and then the dropping tube was used. 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 completion of the dropping, the reaction was continued for another 3 hours to obtain a solution of an acrylic resin having a weight average molecular weight (Mw) of 26000. After cooling to room temperature, about 2 g of the resin solution was sampled, heated and dried at 180 ° C. for 20 minutes to measure the non-volatile content, and xylene was added to the previously synthesized resin solution so that the non-volatile content was 20% by weight. The resin solution 2 was prepared.

<Creation of inkjet ink>
(Examples 1 to 8 and Comparative Examples 1 to 2)
With the ink composition shown in Table 1, weigh the quantum dot solution, the fine particle (B) solution (not added to the comparative example), the resin solution, and the solvent in this order in a container that can be sealed, and then seal the ink 3 Penetrated for minutes to create an inkjet ink.

<Evaluation method>
Table 1 shows the evaluation results obtained by the following evaluation methods.
(Viscosity measurement)
The measurement was performed at 25 ° C. using a vibrating viscometer Viscomate VM-10A-L (manufactured by SEKONIC).
(Visual inspection)
Ink appearance It is not possible to make ink with Δ to ×, where 〇 is a transparent state without turbidity, Δ is turbidity, and × is a precipitate.
Inkjet ejection property 〇 is the one that can be ejected according to the printing pattern, × is the one that has an abnormality such as nozzle clogging, and × cannot be printed.
Appearance of printed matter △ ~ × is inappropriate, where 〇 is the image according to the print pattern, 〇 △ is the case where faintness is seen, Δ is the distorted image, and × is the state where the image is attached without any evidence of the print pattern.
(Inkjet ejection test conditions)
Printing Press DimaticsMaterialsPrinter
Cartridge 10DimaticsMaterialsCartriges, 10pL
Printed circuit board with grid pattern at 1 mm intervals Round cover glass, manufactured by Matsunami Glass Industry Substrate temperature 30 ° C
Dry after printing 40 ° C for 20 minutes (quantum yield measurement)
Measuring machine Absolute PL quantum yield measuring device C9920-02
Excitation wavelength 400nm Integral range 375-425nm
Fluorescence integration range 430-800 nm
The QY (quantum yield) maintenance rate was set to 1 at the initial stage of printing, and the ratio after 4 weeks was shown.

It was confirmed that the inkjet ink of the present invention can be used for inkjet printing and can be printed with a high quantum yield. It is assumed that other coating liquids, coatings made by printing methods using ink, and printed matter have almost the same characteristics, and wavelength conversion films and color filters using these have the desired performance. It was shown that it can exert.

<Creation of electroluminescent element>
As described below, an electroluminescent device was created. In the examples, all mixing ratios indicate weight ratios unless otherwise specified. Thin-film deposition (vacuum vapor 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.
Inkjet ejection test conditions Printing machine DimaticsMaterialsPrinter
Cartridge 10DimaticsMaterialsCartriges, 10pL
Print pattern solid (area in the range of 1.2 cm x 1.2 cm where a total of 6 elements of 2 mm x 2 mm are formed)
Substrate temperature 30 ° C
After printing and drying at 40 ° C. for 20 minutes, the light emitting characteristics of the element were measured using an electroluminescent element having a light emitting element area of 2 mm × 2 mm.

(Example 9)
In a container that can be sealed, 1 part of the quantum dot dispersion liquid QD-1, 1 part of the fine particle (B) dispersion liquid NP-1, 2 parts of the resin solution 1, and then 60 parts of decan as a solvent are weighed in this order. Then, it was sealed and infiltrated for 3 minutes to prepare an inkjet ink.
PEDOT / PSS (poly (3,4-ethylenedioxy) -2,5-thiophene / polystyrene sulfonic acid, CLEVIOUS (registered trademark) PVP CH8000 manufactured by Heraeus) is spin-coated on the cleaned glass plate with ITO electrode. A film was formed by the method and dried at 110 ° C. for 20 minutes to obtain a hole injection layer having a film thickness of 35 nm. Next, poly (N-vinylcarbazole) was dissolved in monochlorobenzene at a concentration of 1.0% by weight, a film was formed by a spin coating method, and dried at 110 ° C. for 20 minutes to transport holes having a film thickness of 35 nm. Formed a layer. Using the prepared inkjet ink, a light emitting layer having a film thickness of 20 nm was formed by inkjet ejection printing under the above conditions, and then spin-coated with an isopropanol dispersion N-10 of zinc oxide manufactured by Avantama. A film was formed by the method to form an electron transport layer of 80 nm. Finally, aluminum (Al) was vapor-deposited at 200 nm to form an electrode, and an electroluminescent device was obtained. This element exhibited red emission at 8 V with an external quantum efficiency of 3.5% and an emission luminance of 15,000 (cd / m2), the peak wavelength of the emission spectrum was 653 nm, and the full width at half maximum was 55 nm. When this device was driven at a constant current at room temperature with a luminous brightness of 1000 (cd / m2), the luminance half life was 1000 hours or more. The luminous efficiency when driven at a current density of 10 (mA / cm ² ) is 3.5 (cd / A), and the relative brightness after continuous driving for 100 hours in an environment of 80 ° C. (= (100 hours). Later brightness) / (initial brightness)) was 0.85.

(Example 10)
In a container that can be sealed, weigh 1 part of the quantum dot dispersion liquid QD-2, 1 part of the fine particle (B) dispersion liquid NP-2, 2 parts of the resin solution 2, and then 60 parts of trimethylbenzene as a solvent. After that, the ink was sealed and infiltrated for 3 minutes to prepare an inkjet ink.
Each layer was prepared in the same manner as in Example 9 except that this was replaced with the inkjet ink of Example 9 to form a light emitting layer, and an electroluminescent element was obtained. This element exhibited green emission with an external quantum efficiency of 4.4% and an emission luminance of 25,000 (cd / m2) at 8 V, the peak wavelength of the emission spectrum was 545 nm, and the full width at half maximum was 45 nm. When this device was driven at a constant current at room temperature with a luminous brightness of 1000 (cd / m2), the luminance half life was 1000 hours or more. The luminous efficiency when driven at a current density of 10 (mA / cm2) is 6.1 (cd / A), and the relative brightness after 100 hours of continuous driving in an environment of 80 ° C. (= (after 100 hours). Luminance) / (initial luminance)) was 0.90.

(Example 11)
In a container that can be sealed, 0.1 part of the quantum dot dispersion liquid QD-2, 1.9 parts of the fine particle (B) dispersion liquid NP-2, 2 parts of the resin solution 2, and then 60 parts of trimethylbenzene as a solvent. Weighed in order, then sealed and infiltrated for 3 minutes to make an inkjet ink.
Each layer was prepared in the same manner as in Example 9 except that this was replaced with the inkjet ink of Example 9 to form a light emitting layer, and an electroluminescent element was obtained. This element exhibited green emission with an external quantum efficiency of 5.5% and an emission luminance of 33000 (cd / m2) at 8 V, the peak wavelength of the emission spectrum was 542 nm, and the full width at half maximum was 30 nm. When this device was driven at a constant current at room temperature with a luminous brightness of 1000 (cd / m2), the luminance half life was 1000 hours or more. The luminous efficiency when driven at a current density of 10 (mA / cm2) is 8.2 (cd / A), and the relative brightness after 100 hours of continuous driving in an environment of 80 ° C. (= (after 100 hours). Luminance) / (initial luminance)) was 0.92.

(Comparative Example 3)
In a container that can be sealed, weigh 2 parts of the quantum dot dispersion QD-2, 2 parts of the resin solution 2, and then 60 parts of trimethylbenzene as the solvent, then seal and infiltrate for 3 minutes. Inkjet ink was created.
Each layer was prepared in the same manner as in Example 9 except that this was replaced with the inkjet ink of Example 9 to form a light emitting layer, and an electroluminescent element was obtained. This element exhibited green emission at 8 V with an external quantum efficiency of 2.9% and an emission luminance of 12000 (cd / m2), the peak wavelength of the emission spectrum was 546 nm, and the full width at half maximum was 60 nm. When this device was driven at a constant current at room temperature with a luminous brightness of 1000 (cd / m2), the luminance half life was 1000 hours or more. The luminous efficiency when driven at a current density of 10 (mA / cm2) is 3.3 (cd / A), and the relative brightness after 100 hours of continuous driving in an environment of 80 ° C. (= (after 100 hours). Luminance) / (initial luminance)) was 0.79.

By producing a light emitting device using the inkjet ink made of the semiconductor fine particle composition of the present invention, it was possible to produce an element having excellent light emitting characteristics and stability. It is expected that excellent characteristics can be exhibited in light emitting devices manufactured by other coating methods and printing methods using other coating liquids and inks.

Claims (12)

A semiconductor fine particle composition comprising a semiconductor fine particle (A) having a core / shell structure, fine particles (B) composed only of compounds constituting the shell, and a solvent .
The first aspect of claim 1, wherein the mass ratio of the semiconductor fine particles (A) having a core / shell structure to the fine particles (B) composed only of the compounds constituting the shell is 1: 5 to 5: 1. Semiconductor fine particle composition . The semiconductor fine particle composition according to claim 1 , wherein the fine particles (B) composed of only the compounds constituting the shell contain ZnS particles. The semiconductor fine particle composition according to claim 1 or 2 , wherein the semiconductor fine particles (A) having a core / shell structure are quantum dots. The semiconductor fine particle composition according to any one of claims 1 to 3, further comprising a resin. A coating liquid comprising the semiconductor fine particle composition according to any one of claims 1 to 4. A coated product formed by using the coating liquid according to claim 5. An ink composition comprising the semiconductor fine particle composition according to any one of claims 1 to 4. An inkjet ink comprising the ink composition according to claim 7. A printed matter formed by using the ink composition according to claim 7. A wavelength conversion film formed by using the coating liquid according to claim 5 or the ink composition according to claim 7. A color filter formed by using the coating liquid according to claim 5 or the ink composition according to claim 7. A light emitting device in which the light emitting layer is formed by using the coating liquid according to claim 5 or the ink composition according to claim 7.