Ink composition, film using the ink composition, and electrophoretic device and display device including the film

Abstract

Provided are an ink composition containing (A) a semiconductor nanorod containing a functional group of a specific structure and (B) a solvent, a film manufactured using the ink composition, and an electrophoretic device and a display device including the film.

Description

Technical Field

[0001] The present disclosure relates to an ink composition, a layer using the ink composition, an electrophoretic device including the layer, and a display apparatus. Background Art

[0002] LEDs have been actively developed since 1992 when Nakamura and others from Japanese Nichia Corp. succeeded in fusing high-quality single-crystal GaN nitride semiconductors by applying a low-temperature GaN compound buffer layer. LEDs are semiconductor devices that convert electrical signals into light having a wavelength in a desired region by using the characteristics of compound semiconductors, and have a structure in which an n-type semiconductor crystal in which a plurality of carriers are electrons and a p-type semiconductor crystal in which a plurality of carriers are holes are combined with each other.

[0003] This LED semiconductor has high light conversion efficiency, and therefore consumes very little energy, and has a semi-permanent service life, and is also environmentally friendly, and is therefore called a light revolution as a green material. In recent years, with the development of compound semiconductor technology, high-brightness red, orange, green, blue, and white LEDs have been developed, and are being applied to many fields such as traffic lights, mobile phones, headlights, outdoor billboards, LCD BLUs (backlight units), and indoor / outdoor lighting, and they are actively studied at home and abroad. In particular, GaN-based compound semiconductors with a wide bandgap are materials for manufacturing LED semiconductors that emit light in the green, blue, and ultraviolet (UV) regions, and since blue LED devices are used to manufacture white LED devices, a lot of research has been done on this.

[0004] In these series of research, research on using ultra-small LED devices with nanometer or micrometer unit sizes is being actively carried out, and in addition, research on using these ultra-small LED devices in lighting and displays is being continuously carried out. In these studies, electrodes capable of applying power to ultra-small LED devices, the arrangement of electrodes for reducing the space occupied by electrodes, methods of mounting ultra-small LED devices on the arranged electrodes, etc. continue to attract attention.

[0005] Among them, due to the size limitation of the ultra-small LED device, the method of mounting the ultra-small LED device on the set electrode still has the difficulty of arranging and mounting the ultra-small LED device on the electrode as expected. The reason is that the ultra-small LED device is nano-scale or micro-scale, and therefore cannot be arranged and mounted on the target electrode area one by one by hand.

[0006] Recently, as the demand for nano-scale ultra-small LED devices increases, attempts have been made to manufacture nano-scale GaN-based compounds or InGaN-based compound semiconductors into rods, but there is a problem that the dispersion stability of the nanorods themselves in the solvent (or polymerizable compound) is greatly deteriorated. So far, there has been no introduction of a technology for improving the dispersion stability of semiconductor nanorods in solvents (or polymerizable compounds). Therefore, research is being conducted on curable compositions containing semiconductor nanorods that can improve the dispersion stability of semiconductor nanorods in solvents (or polymerizable compounds) and achieve high dielectric electrophoresis rates. Summary of the invention

[0007] Technical issues

[0008] The embodiment provides an ink composition having excellent electrophoretic characteristics of semiconductor nanorods.

[0009] Another embodiment provides a layer manufactured using the ink composition.

[0010] Another embodiment provides an electrophoretic device and a display device including the layer.

[0011] Technical Solution

[0012] The embodiment provides an ink composition including: (A) a semiconductor nanorod including at least one of the functional groups represented by Chemical Formula 1-1 to Chemical Formula 1-3; and (B) a solvent.

[0013] [Chemical formula 1-1]

[0014]

[0015] [Chemical formula 1-2]

[0016]

[0017] [Chemical formula 1-3]

[0018]

[0019] In Chemical Formula 1-1 to Chemical Formula 1-3,

[0020] R 1 To R 3 are each independently hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C1 to C20 alkoxy group, or a substituted or unsubstituted C6 to C20 aryl group,

[0021] L 1 and L 2are each independently a substituted or unsubstituted C1 to C20 alkylene group,

[0022] n is an integer from 0 to 20, and

[0023] ☆ indicates a portion connected to the semiconductor nanorod.

[0024] L 1 and L 2 may each independently be an unsubstituted C1 to C20 alkylene group. In this case, L 1 and L 2 Each may be independently represented by Chemical Formula L-1 or Chemical Formula L-2.

[0025] [Chemical formula L-1]

[0026]

[0027] [Chemical formula L-2]

[0028]

[0029] L 1 and L 2 may each independently be a substituted C1 to C20 alkylene group. In this case, L 1 and L 2 Each may be independently represented by one of Chemical Formula L-3 to Chemical Formula L-7.

[0030] [Chemical formula L-3]

[0031]

[0032] [Chemical formula L-4]

[0033]

[0034] [Chemical formula L-5]

[0035]

[0036] [Chemical formula L-6]

[0037]

[0038] [Chemical formula L-7]

[0039]

[0040] R 1 and R 2 Each independently may be a substituted or unsubstituted C1 to C20 alkoxy group.

[0041] R 3 It may be a substituted or unsubstituted C1 to C20 alkyl group.

[0042] The semiconductor nanorods may have a diameter of about 300 nm to about 900 nm.

[0043] The semiconductor nanorods may have a length of about 4 μm to about 6 μm.

[0044] The semiconductor nanorods may include a GaN-based compound, an InGaN-based compound, or a combination thereof.

[0045] The semiconductor nanorods may have a surface coated with a metal oxide.

[0046] The metal oxide may include aluminum oxide, silicon dioxide, or a combination thereof.

[0047] The functional group represented by Chemical Formula 1 may be connected to the metal oxide coating on the surface of the semiconductor nanorod.

[0048] The semiconductor nanorods may be included in an amount of about 0.01 wt % to about 10 wt % based on the total amount of the ink composition.

[0049] The solvent may be a citrate based solvent.

[0050] The ink composition may include: malonic acid; 3-amino-1,2-propanediol; a silane-based coupling agent; a leveling agent; a fluorine-based surfactant; or a combination thereof.

[0051] The ink composition may be an ink composition for an electrophoretic device.

[0052] Another embodiment provides a layer manufactured using the ink composition.

[0053] Another embodiment provides an electrophoresis device comprising the layer.

[0054] Another embodiment provides a display device including the layer.

[0055] Other embodiments of the invention are included in the detailed description below.

[0056] Beneficial Effects

[0057] The ink composition including the semiconductor nanorods can provide a curable composition having excellent electrophoretic characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 is an example of a cross-sectional view of a semiconductor nanorod for a curable composition according to an embodiment. DETAILED DESCRIPTION

[0059] Hereinafter, embodiments of the present invention are described in detail. However, these embodiments are only examples, the present invention is not limited thereto, and the present invention is defined by the scope of the claims.

[0060] As used herein, when a specific definition is not otherwise provided, an “alkyl group” refers to a C1 to C20 alkyl group, an “alkenyl group” refers to a C2 to C20 alkenyl group, a “cycloalkenyl group” refers to a C3 to C20 cycloalkenyl group, a “heterocycloalkenyl group” refers to a C3 to C20 heterocycloalkenyl group, an “aryl group” refers to a C6 to C20 aryl group, an “arylalkyl group” refers to a C6 to C20 arylalkyl group, an “alkylene group” refers to a C1 to C20 alkylene group, an “arylene group” refers to a C6 to C20 arylene group, an “alkylarylene group” refers to a C6 to C20 alkylarylene group, a “heteroarylene group” refers to a C3 to C20 heteroarylene group, and an “alkyleneoxy group” refers to a C1 to C20 alkyleneoxy group.

[0061] As used herein, when a specific definition is not otherwise provided, “substituted” may refer to substitution in which at least one hydrogen is replaced by a halogen atom (F, Cl, Br, I), a hydroxyl group, a C1 to C20 alkoxy group, a nitro group, a cyano group, an amine group, an imino group, an azido group, an amidino group, a hydrazine group, a hydrazone group, a carbonyl group, a carbamoyl group, a thiol group, an ester group, an ether group, a carboxyl group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid or a salt thereof, a C1 to C20 alkyl group, a C2 to C20 alkenyl group, a C2 to C20 alkynyl group, a C6 to C20 aryl group, a C3 to C20 cycloalkyl group, a C3 to C20 cycloalkenyl group, a C3 to C20 cycloalkynyl group, a C2 to C20 heterocycloalkyl group, a C2 to C20 heterocycloalkenyl group, a C2 to C20 heterocycloalkynyl group, a C3 to C20 heteroaryl group, or a combination thereof.

[0062] As used herein, when a specific definition is not otherwise provided, “hetero” may refer to one substituted with at least one hetero atom of N, O, S, and P in a chemical formula.

[0063] As used herein, when specific definition is not otherwise provided, “(meth)acrylate” refers to both “acrylate” and “methacrylate”, and “(meth)acryl-based” refers to both “acryl-based” and “methacryl-based”.

[0064] As used herein, when no specific definition is otherwise provided, the term "combination" means mixing or copolymerization.

[0065] As used herein, unless a specific definition is otherwise provided, when a chemical bond is not drawn where it should be given, a hydrogen atom is bonded at that position.

[0066] In this specification, semiconductor nanorods refer to rod-shaped semiconductors having a nanometer-sized diameter.

[0067] As used herein, when a specific definition is not otherwise provided, "*" indicates a point of connection of the same or different atoms or chemical formulas.

[0068] The ink composition according to the embodiment includes: (A) a semiconductor nanorod including at least one of the functional groups represented by Chemical Formula 1-1 to Chemical Formula 1-3; and (B) a solvent.

[0069] [Chemical formula 1-1]

[0070]

[0071] [Chemical formula 1-2]

[0072]

[0073] [Chemical formula 1-3]

[0074]

[0075] In Chemical Formula 1-1 to Chemical Formula 1-3,

[0076] R 1 To R 3 are each independently hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C1 to C20 alkoxy group, or a substituted or unsubstituted C6 to C20 aryl group,

[0077] L 1 and L 2 are each independently a substituted or unsubstituted C1 to C20 alkylene group,

[0078] n is an integer from 0 to 20, and

[0079] ☆ indicates the portion connected to the semiconductor nanorod.

[0080] Recently, research has been actively conducted on various concepts having the effect of improving energy efficiency and preventing efficiency degradation of conventional LEDs such as micro LEDs, mini LEDs, etc. Among them, alignment (electrophoresis) of InGaN-based nanorod LEDs using an electric field has attracted attention as a method for significantly reducing the complexity and expensive process costs of micro LEDs, mini LEDs, etc.

[0081] However, organic solvents (PGMEA, GBL, PGME, ethyl acetate, IPA, etc.) conventionally used in displays and electronic materials have low viscosity, and thus inorganic nanorod particles having a high density may precipitate too quickly and thus agglomerate, and further, may volatilize quickly during solvent drying after dielectrophoresis and thus may deteriorate the alignment characteristics. Conventionally, efforts have been made to change the composition of the solvent, etc. to solve the above problems, but unlike conventional methods, the present inventors have confirmed that it is not the solvent but the surface treatment of the semiconductor nanorods to ensure excellent dispersion stability in organic solvents, etc. and improve the precipitation rate and dielectrophoretic alignment characteristics, thereby completing the present invention.

[0082] Hereinafter, each component is described in detail.

[0083] (A) Semiconductor Nanorods

[0084] The semiconductor nanorods are particularly surface-treated by using the compound represented by Chemical Formula 1 to increase dispersion stability in an organic solvent and greatly improve precipitation speed and dielectrophoretic alignment characteristics.

[0085] For example, when L 1 and L 2 When each independently is an unsubstituted C1 to C20 alkylene group, L 1 and L 2 It may be represented by Chemical Formula L-1 or Chemical Formula L-2, but is not necessarily limited thereto.

[0086] [Chemical formula L-1]

[0087]

[0088] [Chemical formula L-2]

[0089]

[0090] For example, when L 1 and L 2 When each is independently a substituted C1 to C20 alkylene group, L 1 and L 2 It may be represented by any one of Chemical Formula L-3 or Chemical Formula L-7, but is not necessarily limited thereto.

[0091] [Chemical formula L-3]

[0092]

[0093] [Chemical formula L-4]

[0094]

[0095] [Chemical formula L-5]

[0096]

[0097] [Chemical formula L-6]

[0098]

[0099] [Chemical formula L-7]

[0100]

[0101] For example, the functional group represented by Chemical Formula 1 is a silane group containing a substituted or unsubstituted alkyleneoxy group, particularly a siloxane group containing a substituted or unsubstituted alkyleneoxy group. The semiconductor nanorods surface-treated with such a functional group have significantly better dispersion stability in an organic solvent than when the surface is not treated with a functional group or the surface is treated with a functional group not containing a substituted or unsubstituted alkyleneoxy group. Therefore, it can greatly affect the improvement of the dielectrophoretic characteristics of the ink composition.

[0102] For example, R 1 and R 2 Each independently may be a substituted or unsubstituted C1 to C20 alkoxy group.

[0103] For example, R 3 It may be a substituted or unsubstituted C1 to C20 alkyl group.

[0104] The semiconductor nanorods may include a GaN-based compound, an InGaN-based compound, or a combination thereof, and may have a surface coated with a metal oxide.

[0105] For the dispersion stability of the semiconductor nanorod ink solution (semiconductor nanorods + solvent), it usually takes about 3 hours, which is very insufficient time for a large-area inkjet process. However, by coating the surface of the semiconductor nanorods with a metal oxide including aluminum oxide, silicon dioxide or a combination thereof to form a coating or insulating layer (Al 2 O 3 or SiO x ), the compatibility with the solvent described later can be maximized.

[0106] For example, the coating layer or the insulating layer coated with the metal oxide may have a thickness of about 40 nm to about 60 nm.

[0107] For example, the functional group represented by Chemical Formula 1 may be attached to a metal oxide coating or an insulating layer on the surface of the semiconductor nanorod. In this case, since the compatibility with a solvent described later becomes very excellent, the dispersion stability of the semiconductor nanorod and the dielectrophoretic characteristics of the ink composition can be greatly improved.

[0108] The semiconductor nanorod may include an n-type confinement layer and a p-type confinement layer, and a multi-quantum well active portion (MQW active region; multi-quantum well active region) may be located between the n-type confinement layer and the p-type confinement layer.

[0109] For example, the semiconductor nanorods may have a diameter of about 300 nm to about 900 nm, eg, about 600 nm to about 700 nm.

[0110] For example, the semiconductor nanorods may have a length of about 4 μm to about 6 μm.

[0111] For example, when the semiconductor nanorods include an aluminum oxide insulating layer, they may have a thickness of about 5 g / cm 3 To about 6g / cm 3 density.

[0112] For example, a semiconductor nanorod can have a -13 g to about 1×10 -11 The mass of g.

[0113] When the semiconductor nanorods have the above diameter, length, density, and type, surface coating of the metal oxide may be promoted, and the dispersion stability of the semiconductor nanorods may be maximized.

[0114] The semiconductor nanorods may be included in an amount of about 0.01 wt % to about 10 wt %, for example, about 0.01 wt % to about 5 wt %, based on the total amount of the ink composition. Alternatively, the semiconductor nanorods may be included in an amount of about 0.01 wt % to about 0.5 wt %, for example, about 0.01 wt % to about 0.1 wt %, based on 100 wt % of the solvent in the ink composition. When the semiconductor nanorods are included within the above range, the dispersibility in the ink is good, and the pattern produced may have excellent brightness.

[0115] (B) Solvent

[0116] Organic solvents such as propylene glycol monomethyl ether acetate (PGMEA), γ-butyrolactone (GBL), polyethylene glycol methyl ether (PGME), ethyl acetate, isopropyl alcohol (IPA), etc., which have been used in conventional displays and electronic materials, have such low viscosity that inorganic material nanorod particles with high density precipitate too quickly, resulting in unsatisfactory dielectrophoresis characteristics. According to the embodiment, the above problem can be solved by surface treatment of semiconductor nanorods, but if there is a solvent that can impart precipitation stability to semiconductor nanorods, it may be more desirable to use the solvent as a solvent.

[0117] For example, the solvent may be a citrate-based solvent, but is not necessarily limited thereto.

[0118] For example, the solvent can have a viscosity greater than or equal to about 3 cps at 50°C.

[0119] For example, the solvent may include a compound represented by Chemical Formula 2 or Chemical Formula 3.

[0120] [Chemical formula 2]

[0121]

[0122] [Chemical formula 3]

[0123]

[0124] In Chemical Formula 2 and Chemical Formula 3,

[0125] R 11 is a hydrogen atom or *-C(=O)R' (wherein R' is a hydrogen atom or a substituted or unsubstituted C1 to C10 alkyl group),

[0126] R 12 To R 14 are each independently a substituted or unsubstituted C2 to C20 alkyl group,

[0127] R 15 is a substituted or unsubstituted C1 to C20 alkyl group, or a C6 to C20 aryl group which is substituted or unsubstituted by a C2 to C10 alkoxy group,

[0128] L 11 To L 13 are each independently a substituted or unsubstituted C1 to C20 alkylene group, and

[0129] m is an integer of 1-20.

[0130] For example, the compound represented by Chemical Formula 2 may include a compound represented by Chemical Formula 2-1 or Chemical Formula 2-2.

[0131] [Chemical formula 2-1]

[0132]

[0133] [Chemical formula 2-2]

[0134]

[0135] For example, the compound represented by Chemical Formula 3 may include a compound represented by any one of Chemical Formula 3-1 to Chemical Formula 3-4.

[0136] [Chemical formula 3-1]

[0137]

[0138] [Chemical formula 3-2]

[0139]

[0140] [Chemical formula 3-3]

[0141]

[0142] [Chemical formula 3-4]

[0143]

[0144] The solvent may be included in an amount of about 5 wt % to about 99.99 wt %, for example, about 20 wt % to about 99.95 wt %, based on the total amount of the ink composition.

[0145] Polymerizable monomer

[0146] The ink composition according to the embodiment may further include a polymerizable compound, if necessary. The polymerizable compound may be used by mixing a monomer or an oligomer generally used in a conventional curable composition.

[0147] For example, the polymerizable compound may be a polymerizable monomer having a carbon-carbon double bond at its terminal.

[0148] For example, the polymerizable compound may be a polymerizable monomer having at least one functional group represented by Chemical Formula A-1 or a functional group represented by Chemical Formula A-2 at its terminal.

[0149] [Chemical formula A-1]

[0150]

[0151] [Chemical formula A-2]

[0152]

[0153] In Chemical Formula A-1 and Chemical Formula A-2,

[0154] L a is a substituted or unsubstituted C1 to C20 alkylene group, and

[0155] R a is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group.

[0156] The polymerizable compound contains at least one carbon-carbon double bond at the terminal, specifically, a functional group represented by Chemical Formula A-1 or a functional group represented by Chemical Formula A-2, thereby forming a crosslinked structure with the surface modification compound. The crosslinked body thus formed can further enhance the dispersion stability of the semiconductor nanorods by further doubling one type of steric hindrance effect.

[0157] For example, the polymerizable compound including at least one functional group represented by Chemical Formula A-1 at the terminal may be divinylbenzene, triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, triallyl phosphate, triallyl phosphite, triallyl triazine, diallyl phthalate, or a combination thereof, but is not necessarily limited thereto.

[0158] For example, the polymerizable compound including at least one functional group represented by Chemical Formula A-2 at the terminal may be ethylene glycol diacrylate, triethylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, dipentaerythritol diacrylate, dipentaerythritol triacrylate, dipentaerythritol pentaacrylate, pentaerythritol hexaacrylate, bisphenol A diacrylate, trimethylolpropane triacrylate, novolac epoxy acrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, multifunctional epoxy (meth) acrylate, multifunctional urethane (meth) acrylate, KAYARAD from Nippon Chemical Co., Ltd. DPCA-20, KAYARAD DPCA-30, KAYARAD DPCA-60, KAYARAD DPCA-120 or KAYARAD DPEA-12, or a combination thereof, but not necessarily limited thereto.

[0159] The polymerizable compound may be used after being treated with an acid anhydride to impart better developability.

[0160] Polymerization initiator

[0161] If necessary, the curable composition according to the embodiment may further include a polymerization initiator, for example, a photopolymerization initiator, a thermal polymerization initiator, or a combination thereof.

[0162] The photopolymerization initiator may be a commonly used initiator for a curable composition, and may be, for example, an acetophenone-based compound, a benzophenone-based compound, a thioxanthone-based compound, a benzoin-based compound, a triazine-based compound, an oxime-based compound, an aminoketone-based compound, or the like, but is not necessarily limited thereto.

[0163] Examples of the acetophenone-based compound may be 2,2′-diethoxyacetophenone, 2,2′-dibutoxyacetophenone, 2-hydroxy-2-methylpropiophenone, p-tert-butyltrichloroacetophenone, p-tert-butyldichloroacetophenone, 4-chloroacetophenone, 2,2′-dichloro-4-phenoxyacetophenone, 2-methyl-1-(4-(methylthio)phenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, and the like.

[0164] Examples of the benzophenone-based compound may be benzophenone, benzoyl benzoate, benzoylmethyl benzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-dimethylaminobenzophenone, 4,4'-dichlorobenzophenone, 3,3'-dimethyl-2-methoxybenzophenone, and the like.

[0165] Examples of the thioxanthone-based compound may be thioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 2-chlorothioxanthone, and the like.

[0166] Examples of the benzoin-based compound may be benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, and the like.

[0167] Examples of the triazine-based compound may include 2,4,6-trichloro-s-triazine, 2-phenyl-4,6-bis(trichloromethyl)-s-triazine, 2-(3',4'-dimethoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4'-methoxynaphthyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(p-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(p-tolyl)-4,6-bis(trichloromethyl)-s-triazine, )-s-triazine, 2-biphenyl-4,6-bis(trichloromethyl)-s-triazine, bis(trichloromethyl)-6-phenylvinyl-s-triazine, 2-(naphthalen-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxynaphthalen-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2-4-bis(trichloromethyl)-6-piperonyl-s-triazine, 2-4-bis(trichloromethyl)-6-(4-methoxyphenylvinyl)-s-triazine, etc.

[0168] Examples of oxime-based compounds may be O-acyl oxime-based compounds, 2-(O-benzoyl oxime)-1-[4-(phenylthio)phenyl]-1,2-octanedione, 1-(O-acetoximo)-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone, O-ethoxycarbonyl-α-oxyamino-1-phenylpropan-1-one, and the like. Specific examples of O-acyl oxime-based compounds may be 1,2-octanedione, 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one, 1-(4-phenylthiophenyl)-butane-1,2-dione-2-oxime-O-benzoate, 1-(4-phenylthiophenyl)-octane-1,2-dione-2-oxime-O-benzoate, 1-(4-phenylthiophenyl)-octane-1,2-dione-2-oxime-O-benzoate, 1-(4-phenylthiophenyl)-octane-1-one oxime-O-acetate, 1-(4-phenylthiophenyl)-butan-1-one oxime-O-acetate, and the like.

[0169] Examples of the aminoketone-based compound may be 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 and the like.

[0170] The photopolymerization initiator may further include a carbazole-based compound, a diketone-based compound, a sulfonium borate-based compound, a diazo-based compound, an imidazole-based compound, a biimidazole-based compound, and the like, in addition to the compounds.

[0171] The photopolymerization initiator may be used together with a photosensitizer capable of causing a chemical reaction by absorbing light and becoming excited, and then transferring its energy.

[0172] Examples of the photosensitizer may include tetraethylene glycol bis-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate, dipentaerythritol tetrakis-3-mercaptopropionate, and the like.

[0173] Examples of thermal polymerization initiators may include peroxides, specifically, benzoyl peroxide, dibenzoyl peroxide, lauryl peroxide, dilauryl peroxide, di-tert-butyl peroxide, cyclohexane peroxide, methyl ethyl ketone peroxide, hydroperoxides (e.g., tert-butyl hydroperoxide, cumene hydroperoxide, etc.), dicyclohexyl peroxydicarbonate, 2,2-azo-bis(isobutyronitrile), tert-butyl perbenzoate, 2,2'-azobis-2-methylpropionitrile, and the like, but are not necessarily limited thereto, and any one widely known in the art may be used.

[0174] The polymerization initiator may be included in an amount of about 1 wt % to about 5 wt %, for example, about 2 wt % to about 4 wt %, based on the total amount of solid components constituting the ink composition. When the polymerization initiator is included within the above range, excellent reliability may be obtained due to sufficient curing during exposure or heat curing.

[0175] Other additives

[0176] The curable composition according to the embodiment may further include a polymerization inhibitor as needed, the polymerization inhibitor including a hydroquinone-based compound, a catechol-based compound, or a combination thereof. Since the ink composition according to the embodiment further includes a hydroquinone-based compound, a catechol-based compound, or a combination thereof, crosslinking at room temperature can be prevented during exposure after printing (coating) the ink composition.

[0177] For example, the hydroquinone-based compound, the catechol-based compound or a combination thereof can be hydroquinone, methylhydroquinone, methoxyhydroquinone, tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, 2,5-bis(1,1-dimethylbutyl)hydroquinone, 2,5-bis(1,1,3,3-tetramethylbutyl)hydroquinone, catechol, tert-butylcatechol, 4-methoxyphenol, pyrogallol, 2,6-di-tert-butyl-4-methylphenol, 2-naphthol, tris(N-hydroxy-N-nitrosophenylamino-O,O')aluminum or a combination thereof, but are not necessarily limited thereto.

[0178] The hydroquinone-based compound, the catechol-based compound, or a combination thereof may be used in the form of a dispersion, and the polymerization inhibitor in the form of a dispersion may be included in an amount of about 0.001 wt % to about 1 wt %, for example, about 0.01 wt % to about 0.1 wt %, based on the total amount of the ink composition. When the polymerization inhibitor is included within the range, the aging problem at room temperature may be solved, and at the same time, sensitivity deterioration and surface delamination phenomena may be suppressed.

[0179] In addition to the polymerization inhibitor, the ink composition according to the embodiment may include: malonic acid; 3-amino-1,2-propanediol; a silane-based coupling agent; a leveling agent; a fluorine-based surfactant; or a combination thereof as needed.

[0180] For example, the ink composition may further include a silane-based coupling agent having a reactive substituent (eg, a vinyl group, a carboxyl group, a methacryloxy group, an isocyanate group, an epoxy group, etc.) to improve close contact properties with a substrate.

[0181] Examples of silane-based coupling agents may be trimethoxysilylbenzoic acid, γ-methacryloyloxypropyltrimethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, γ-isocyanatepropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, β-epoxycyclohexyl)ethyltrimethoxysilane, and the like, and these may be used alone or in a mixture of two or more.

[0182] The silane-based coupling agent may be used in an amount of about 0.01 parts by weight to about 10 parts by weight based on 100 parts by weight of the ink composition. When the silane-based coupling agent is included within the range, close contact performance, storage ability, etc. are improved.

[0183] Furthermore, if necessary, the ink composition may further include a surfactant, such as a fluorine-based surfactant, in order to improve coating properties and prevent defect formation.

[0184] Examples of fluorine-based surfactants can be BM-Chemie Inc.'s etc.; MEGAFACE F from Dainippon Ink Kagaku Kogyo Co., Ltd. MEGAFACE F MEGAFACE F MEGAFACE F etc.; FULORAD of Sumitomo 3M Co., Ltd. FULORAD FULORAD FULORAD etc.; SURFLON from ASAHI Glass Co., Ltd. SURFLON SURFLON SURFLON SURFLON etc.; Toray Silicone Co., Ltd. etc.; F-482, F-484, F-478, F-554, etc. from DIC Co., Ltd.

[0185] The fluorine-based surfactant may be included in an amount of about 0.001 parts by weight to about 5 parts by weight based on 100 parts by weight of the ink composition. When the fluorine-based surfactant is included within the above range, coating uniformity is ensured, stains are not generated, and wettability to a glass substrate is excellent.

[0186] In addition, unless the performance is deteriorated, the ink composition may further contain a predetermined amount of other additives such as an antioxidant, a stabilizer, and the like.

[0187] Another embodiment provides a layer using an ink composition.

[0188] Another embodiment may provide an electrophoretic device and / or a display apparatus including the layer.

[0189] Hereinafter, the present invention is illustrated in more detail with reference to Examples. However, these Examples are not intended to be interpreted as limiting the scope of the present invention in any sense.

[0190] (Preparation of Curable Composition)

[0191] Example 1

[0192] 40 ml of 2-[methoxy(polyethyleneoxy) 6 Propyl] trimethoxysilane (CAS No.: 65994-07-2, EO 6-9 -CA, 1% solution in PGMEA) was reacted on a nanorod patterned GaN wafer (4 inches) at room temperature for 15 hours. After the reaction, the wafer was soaked in 50 ml of acetone for 5 minutes to remove excess ligands, and the surface of the wafer was rinsed using 40 ml of acetone. The washed wafer was placed in a 27 kW bath ultrasonic generator together with 35 ml of GBL and ultrasonicated for 5 minutes to separate the rods from the wafer surface by ultrasonic treatment. The separated rods were placed in a FALCON tube for centrifugation, and 10 ml of GBL was added thereto to additionally wash the rods on the bath surface. After discarding the supernatant by centrifugation at 4000 rpm for 10 minutes, the precipitate was redispersed in 40 ml of acetone and foreign matter was filtered out with a 10 μm mesh filter. After additional centrifugation (4000 rpm, 10 minutes), the precipitate was dried in a drying oven (100° C., 1 hour), and then weighed so that the precipitate was dispersed in triethyl 2-acetylcitrate (TEC-Ac) to 0.05 w / w % to prepare an ink composition.

[0193] Example 2

[0194] An ink composition was prepared in the same manner as in Example 1 except that 2-[methoxy(polyethyleneoxy) 9 Propyl] trimethoxysilane (CAS No.: 65994-07-2, EO 9 -CA, 1% solution in PGMEA) to replace 2-[methoxy(polyethyleneoxy) 6 propyl]trimethoxysilane as ligand.

[0195] Comparative Example 1

[0196] An ink composition was prepared in the same manner as in Example 1, except that no ligand was used.

[0197] Comparative Example 2

[0198] An ink composition was prepared in the same manner as in Example 1, except that octadecyltrimethoxysilane (CAS No. 3069-42-9, OD-CA, 1% solution in dodecane) was used instead of 2-[methoxy(polyethyleneoxy) 6 propyl]trimethoxysilane as ligand.

[0199] Comparative Example 3

[0200] The ink composition was prepared in the same manner as in Example 1, except that triethoxy(2,4,4-trimethylpentyl)silane (CAS No. 35435-21-3, TMPCA, 1% solution in PGMEA) was used instead of 2-[methoxy(polyethyleneoxy) 6 propyl]trimethoxysilane as ligand.

[0201] Each structure of the ligands of Example 1 and Example 2 and Comparative Example 2 and Comparative Example 3 is shown in Table 1.

[0202] (Table 1)

[0203]

[0204] evaluate

[0205] The sedimentation speed of the ink compositions of Examples 1 and 2 and Comparative Examples 1 to 3 was evaluated by using Turbiscan, and the dielectrophoresis characteristics were evaluated by reducing the rate using backscattering (BS) 8 hours after measuring the sedimentation speed, TSI (Turbiscan stability index), etc. in Turbiscan, and the results are shown in Table 2.

[0206] (Table 2)

[0207]

[0208]

[0209] Referring to Table 2, Examples 1 and 2 using semiconductor nanorods surface-modified with a hydrophilic ligand containing an alkylene oxide structural unit exhibited improved precipitation rates compared to Comparative Examples 1 to 3, and further exhibited excellent dielectrophoretic properties (improved BS reduction rate, which is not shown in Table 2).

[0210] Although the present invention has been described in conjunction with what are currently considered to be practical exemplary embodiments, it should be understood that the present invention is not limited to the disclosed embodiments, but on the contrary, the present invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Therefore, the above-mentioned embodiments should be understood to be merely examples and not to limit the present invention in any way.

Claims

1. An ink composition comprising: (A) a semiconductor nanorod comprising at least one of the functional groups represented by Chemical Formula 1-1 to Chemical Formula 1-3; and (B) Solvent: [Chemical formula 1-1] [Chemical formula 1-2] [Chemical formula 1-3] in, In Chemical Formula 1-1 to Chemical Formula 1-3, R 1 To R 3 are each independently hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C1 to C20 alkoxy group, or a substituted or unsubstituted C6 to C20 aryl group, L 1 and L 2 are each independently a substituted or unsubstituted C1 to C20 alkylene group, n is an integer from 0 to 20, and ☆ indicates a portion connected to the semiconductor nanorod.

2. The ink composition according to claim 1, wherein L 1 and L 2 Each is independently an unsubstituted C1 to C20 alkylene group.

3. The ink composition according to claim 2, wherein L 1 and L 2 Each is independently represented by Chemical Formula L-1 or Chemical Formula L-2: [Chemical formula L-1] [Chemical formula L-2] 4. The ink composition according to claim 1, wherein L 1 and L 2 Each is independently a substituted C1 to C20 alkylene group.

5. The ink composition according to claim 4, wherein L 1 and L 2 Each is independently represented by any one of Chemical Formula L-3 to Chemical Formula L-7: [Chemical formula L-3] [Chemical formula L-4] [Chemical formula L-5] [Chemical formula L-6] [Chemical formula L-7] 6. The ink composition according to claim 1, wherein R 1 and R 2 Each is independently a substituted or unsubstituted C1 to C20 alkoxy group.

7. The ink composition according to claim 1, wherein R 3 is a substituted or unsubstituted C1 to C20 alkyl group.

8. The ink composition according to claim 1, wherein The semiconductor nanorods have a diameter of about 300 nm to about 900 nm.

9. The ink composition according to claim 1, wherein The semiconductor nanorods have a length of about 4 μm to about 6 μm.

10. The ink composition according to claim 1, wherein The semiconductor nanorods include a GaN-based compound, an InGaN-based compound, or a combination thereof.

11. The ink composition according to claim 1, wherein The semiconductor nanorods have surfaces coated with a metal oxide.

12. The ink composition according to claim 11, wherein The metal oxide includes aluminum oxide, silicon dioxide or a combination thereof.

13. The ink composition according to claim 11, wherein The functional group represented by Chemical Formula 1 is connected to the metal oxide coating layer on the surface of the semiconductor nanorod.

14. The ink composition according to claim 1, wherein The semiconductor nanorods are included in an amount of about 0.01 wt % to about 10 wt % based on the total amount of the ink composition.

15. The ink composition according to claim 1, wherein The solvent is a citrate based solvent.

16. The ink composition according to claim 1, wherein The ink composition further comprises: malonic acid; 3-amino-1,2-propanediol; a silane-based coupling agent; a leveling agent; a fluorine-based surfactant; or a combination thereof.

17. The ink composition according to claim 1, wherein The ink composition is an ink composition for an electrophoretic device.

18. A layer produced using the ink composition according to any one of claims 1 to 17.

19. Electrophoretic device comprising the layer of claim 18.

20. A display device comprising the layer of claim 18.

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