Ink composition, layer using the same, and electrophoretic device and display device including the layer

Abstract

Provided is an ink composition comprising (A) a semiconductor nanorod comprising a functional group of a specific structure and (B) a solvent; a layer manufactured using the ink composition; and an electrophoretic device and a display device comprising the layer.

Description

Technical Field

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

[0002] LEDs have been actively developed since 1992 when Nakamura and others from Japanese Nichia Corp. successfully fused 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 n-type semiconductor crystals in which a plurality of carriers are electrons and p-type semiconductor crystals 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 further, research on using these ultra-small LED devices in lighting and displays is being continuously carried out. In these researches, electrodes capable of applying power to ultra-small LED devices, arrangement of electrodes for reducing the space occupied by electrodes, methods of mounting ultra-small LED devices on arranged electrodes, etc. continue to receive 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 setting 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 manually set and mounted on the target electrode area one by one.

[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 a functional group represented by Chemical Formula 1; and (B) a solvent.

[0013] [Chemical formula 1]

[0014]

[0015] In Chemical Formula 1,

[0016] R 1 and R 2 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;

[0017] R 3 is a substituted or unsubstituted C1 to C10 alkyl group.

[0018] R 1 and R 2 can be the same as each other, R 3 Can be used with R 1 and R 2 different.

[0019] R 1 and R 2Each independently may be a substituted or unsubstituted C1 to C20 alkoxy group.

[0020] R 3 It may be an unsubstituted C1 to C10 alkyl group.

[0021] R 3 It may be an unsubstituted C1 to C8 alkyl group.

[0022] R 3 It may be an unsubstituted C1 to C6 alkyl group.

[0023] R 3 It may be an unsubstituted C2 to C6 alkyl group.

[0024] The semiconductor nanorods may have a diameter of about 300 nm to about 900 nm.

[0025] The semiconductor nanorods may have a length of about 4 μm to about 6 μm.

[0026] The semiconductor nanorods may include a GaN-based compound, an InGaN-based compound, or a combination thereof.

[0027] The semiconductor nanorods may have a surface coated with a metal oxide.

[0028] The metal oxide may include aluminum oxide, silicon dioxide, or a combination thereof.

[0029] The functional group represented by Chemical Formula 1 may be connected to the metal oxide coating layer on the surface of the semiconductor nanorod.

[0030] 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.

[0031] The solvent may include a citrate-based compound.

[0032] The ink composition may further include malonic acid; 3-amino-1,2-propanediol; a silane-based coupling agent; a leveling agent; a fluorine-based surfactant; or a combination thereof.

[0033] The ink composition may be an ink composition for an electrophoretic device.

[0034] Another embodiment provides an ink composition including: (A) semiconductor nanorods surface-modified with a surface-modifying material represented by Chemical Formula 2; and (B) a solvent.

[0035] [Chemical formula 2]

[0036]

[0037] In chemical formula 2,

[0038] R 1 , R 2 and R 4 are each independently a substituted or unsubstituted C1 to C20 alkoxy group, and

[0039] R 3 is a substituted or unsubstituted C1 to C10 alkyl group.

[0040] Another embodiment provides a layer produced using the ink composition.

[0041] Another embodiment provides an electrophoretic device comprising the layer.

[0042] Another embodiment provides a display device including the layer.

[0043] Other embodiments are included in the detailed description below.

[0044] [Beneficial Effects]

[0045] The ink composition including the semiconductor nanorods may provide a curable composition having excellent electrophoretic characteristics (slow sedimentation rate and high dielectrophoretic rate). BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a cross-sectional view of a semiconductor nanorod used in a curable composition according to an embodiment. DETAILED DESCRIPTION

[0047] Hereinafter, the embodiments 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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”.

[0052] As used herein, when no specific definition is otherwise provided, the term "combination" means mixing or copolymerization.

[0053] 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.

[0054] In this specification, semiconductor nanorods refer to rod-shaped semiconductors having a nanometer-sized diameter.

[0055] 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.

[0056] The ink composition according to the embodiment includes: (A) a semiconductor nanorod including a functional group represented by Chemical Formula 1; and (B) a solvent.

[0057] [Chemical formula 1]

[0058]

[0059] In Chemical Formula 1,

[0060] R 1 and R 2are 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;

[0061] R 3 is a substituted or unsubstituted C1 to C10 alkyl group.

[0062] 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.

[0063] 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 settle too quickly and thus aggregate, and further, the organic solvent may volatilize quickly and thus may deteriorate the orientation characteristics during solvent drying after dielectrophoresis. 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 semiconductor nanorods that are surface-treated to ensure excellent dispersion stability in organic solvents, etc. and to improve the sedimentation rate and dielectric orientation characteristics, completing the present invention.

[0064] Specifically, the electrophoresis of semiconductor nanorods can be achieved by inkjetting or slit coating semiconductor nanorod dispersions, but the dispersion stability of the nanorods is a necessary parameter for large-area coatings. In other words, the interaction between "the hydrophilicity or hydrophobicity of the solvent in which the semiconductor nanorods are dispersed" and "the solubility of the surface of the semiconductor nanorods" contributes to the dispersion stability of the semiconductor nanorods. Herein, dispersion stability is an important property that determines processability such as the sedimentation rate of semiconductor nanorods, aggregation between semiconductor nanorods, etc. during dielectrophoresis. According to an embodiment, the solubility interaction between the organic solvent and the ligand in which the semiconductor nanorods are dispersed can be maximized to increase the dispersion stability between the semiconductor nanorods during dielectrophoresis and reduce the sedimentation rate of the semiconductor nanorods, ultimately improving the inkjet processability and orientation characteristics of the ink composition containing semiconductor nanorods.

[0065] Hereinafter, each component is described in detail.

[0066] (A) Semiconductor Nanorods

[0067] The higher the dispersion stability of the ink composition comprising semiconductor nanorods and a solvent, the better the large-area inkjet and dielectrophoresis processability. According to the embodiment, in order to prepare a semiconductor nanorod inkjet solution that can be applied to a large display panel, a ligand having a specific structure can be added to a coating or insulating layer (Al2O3) on the surface of the semiconductor nanorod. 2 O 3 or SiO x ) combines and optimizes the interaction between the ligand and the solvent to maximize dispersion stability.

[0068] The properties of the ink composition containing the semiconductor nanorods can be determined according to whether the semiconductor nanorods are surface treated with ligands. When the surface treatment is performed by applying a hydrophobic ligand, the dispersibility and dielectrophoretic characteristics of the ink composition can be improved compared with the ink composition containing the semiconductor nanorods that have not been surface treated. In particular, in the hydrophobic ligand applied during the surface treatment, the properties can vary depending on the length of the alkyl group constituting the ligand, and after repeating the experiment many times, the inventors have studied the ligand structure with the optimal length, which brings excellent properties, and completed the present invention.

[0069] Surface treatment of semiconductor nanorods, specifically, surface treatment of semiconductor nanorods by using the ligand represented by Chemical Formula 1 (surface modification material represented by Chemical Formula 2) can increase dispersion stability in an organic solvent and significantly improve sedimentation rate and dielectrophoresis orientation characteristics.

[0070] [Chemical formula 2]

[0071]

[0072] In chemical formula 2,

[0073] R 1 , R 2 and R 4 are each independently a substituted or unsubstituted C1 to C20 alkoxy group, and

[0074] R 3 is a substituted or unsubstituted C1 to C10 alkyl group.

[0075] For example, in Formula 1, R 1 and R 2 can be identical to each other, and R 3 Can be used with R 1 and R 2 different.

[0076] For example, in Formula 2, R 1 , R 2 and R 4 can be identical to each other, and R3 Can be used with R 1 and R 2 different.

[0077] For example, in Formula 1, R 1 and R 2 Each independently may be a substituted or unsubstituted C1 to C20 alkoxy group.

[0078] For example, in Formula 2, R 1 , R 2 and R 4 Each independently may be a substituted or unsubstituted C1 to C20 alkoxy group.

[0079] For example, in Formula 1, R 1 and R 2 may each independently represent a substituted or unsubstituted C1 to C20 alkoxy group, and R 3 It may be an unsubstituted C1 to C10 alkyl group.

[0080] For example, in Formula 2, R 1 , R 2 and R 4 may each independently be a substituted or unsubstituted C1 to C20 alkoxy group, and R 3 It may be an unsubstituted C1 to C10 alkyl group.

[0081] For example, in Formula 1, R 1 and R 2 may each independently represent a substituted or unsubstituted C1 to C20 alkoxy group, and R 3 It may be an unsubstituted C1 to C8 alkyl group.

[0082] For example, in Formula 2, R 1 , R 2 and R 4 may each independently be a substituted or unsubstituted C1 to C20 alkoxy group, and R 3 It may be an unsubstituted C1 to C8 alkyl group.

[0083] For example, in Formula 1, R 1 and R 2 may each independently represent a substituted or unsubstituted C1 to C20 alkoxy group, and R 3 It may be an unsubstituted C1 to C6 alkyl group.

[0084] For example, in Formula 2, R 1 , R 2 and R 4may each independently be a substituted or unsubstituted C1 to C20 alkoxy group, and R 3 It may be an unsubstituted C1 to C6 alkyl group.

[0085] For example, in Formula 1, R 1 and R 2 may each independently represent a substituted or unsubstituted C1 to C20 alkoxy group, and R 3 It may be an unsubstituted C2 to C8 alkyl group.

[0086] For example, in Formula 2, R 1 , R 2 and R 4 may each independently be a substituted or unsubstituted C1 to C20 alkoxy group, and R 3 It may be an unsubstituted C2 to C8 alkyl group.

[0087] For example, in Formula 1, R 1 and R 2 may each independently be a substituted or unsubstituted C1 to C20 alkoxy group, and R 3 It may be an unsubstituted C2 to C6 alkyl group.

[0088] For example, in Formula 2, R 1 , R 2 and R 4 may each independently be a substituted or unsubstituted C1 to C20 alkoxy group, and R 3 It may be an unsubstituted C2 to C6 alkyl group.

[0089] That is, by controlling the alkyl group R in the functional group represented by Chemical Formula 1 3 The length and substituents of the nanoparticles can greatly improve the sedimentation rate and dielectrophoretic orientation properties.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] For example, the semiconductor nanorods may have a length of about 4 μm to about 6 μm.

[0097] For example, when the semiconductor nanorods include an aluminum oxide insulating layer, they may have a thickness of about 5 g / cm 3 About 6g / cm 3 density.

[0098] For example, a semiconductor nanorod can have a -13 g to about 1×10 -11 The mass of g.

[0099] 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.

[0100] 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.

[0101] (B) Solvent

[0102] 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 settle 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 sedimentation stability to the semiconductor nanorods, it may be more desirable to use such a solvent.

[0103] For example, the solvent may include a citrate-based compound, but is not necessarily limited thereto.

[0104] For example, the solvent can have a viscosity greater than or equal to about 3 cps at 50°C.

[0105] For example, the solvent may include a compound represented by Chemical Formula 3 or Chemical Formula 4.

[0106] [Chemical formula 3]

[0107]

[0108] [Chemical formula 4]

[0109]

[0110] In Chemical Formula 3 and Chemical Formula 4,

[0111] 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),

[0112] R 12 To R 14 are each independently a substituted or unsubstituted C2 to C20 alkyl group,

[0113] 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,

[0114] L 11 To L 13 are each independently a substituted or unsubstituted C1 to C20 alkylene group, and

[0115] m is an integer of 1-20.

[0116] For example, the compound represented by Chemical Formula 3 may include a compound represented by Chemical Formula 3-1 or Chemical Formula 3-2.

[0117] [Chemical formula 3-1]

[0118]

[0119] [Chemical formula 3-2]

[0120]

[0121] For example, the compound represented by Chemical Formula 4 may include a compound represented by any one of Chemical Formula 4-1 to Chemical Formula 4-4.

[0122] [Chemical formula 4-1]

[0123]

[0124] [Chemical formula 4-2]

[0125]

[0126] [Chemical formula 4-3]

[0127]

[0128] [Chemical formula 4-4]

[0129]

[0130] 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 %, for example about 90 wt % to about 99.99 wt %, based on the total amount of the ink composition.

[0131] Polymerizable monomer

[0132] 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.

[0133] For example, the polymerizable compound may be a polymerizable monomer having a carbon-carbon double bond at its terminal.

[0134] 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.

[0135] [Chemical formula A-1]

[0136]

[0137] [Chemical formula A-2]

[0138]

[0139] In Chemical Formula A-1 and Chemical Formula A-2,

[0140] L a is a substituted or unsubstituted C1 to C20 alkylene group,

[0141] R a is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group.

[0142] 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.

[0143] 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.

[0144] 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.

[0145] The polymerizable compound may be used after being treated with an acid anhydride to impart better developability.

[0146] Polymerization initiator

[0147] The ink composition according to the embodiment may further include a polymerization initiator, for example, a photopolymerization initiator, a thermal polymerization initiator, or a combination thereof, as needed.

[0148] 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.

[0149] 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.

[0150] 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.

[0151] Examples of the thioxanthone-based compound may be thioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 2-chlorothioxanthone, and the like.

[0152] 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.

[0153] 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.

[0154] 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.

[0155] Examples of the aminoketone-based compound may be 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 and the like.

[0156] 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.

[0157] 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.

[0158] Examples of the photosensitizer may include tetraethylene glycol bis-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate, dipentaerythritol tetrakis-3-mercaptopropionate, and the like.

[0159] 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 they are not necessarily limited thereto, and any one widely known in the art may be used.

[0160] 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.

[0161] Other additives

[0162] The curable composition according to the embodiment may further include a 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.

[0163] 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.

[0164] 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.

[0165] 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.

[0166] 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.

[0167] 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.

[0168] 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.

[0169] 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.

[0170] 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.

[0171] 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.

[0172] 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.

[0173] Another embodiment provides a layer using an ink composition.

[0174] Another embodiment may provide an electrophoretic device and / or a display device including the layer.

[0175] 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.

[0176]

Invention Mode

[0177] 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.

[0178] (Preparation of Curable Composition)

[0179] Example 1

[0180] 40ml of hexyltrimethoxysilane (cas#:3069-19-0, HSCA, 1.5mM solution in dodecane) (ligand) was reacted at room temperature on a nanorod patterned GaN wafer (4 inches) for 15 hours. After the reaction, the wafer obtained therefrom was immersed in 50ml of acetone for 5 minutes to remove excess ligand, and the wafer surface was additionally rinsed by using 40ml of acetone. The cleaned wafer was placed in a 27kW bath sonicator with 35ml of GBL, and then ultrasonicated for 5 minutes to separate the rods from the wafer surface. The separated rods were placed in a FALCON centrifuge tube, and 10ml of GBL was added thereto to additionally wash the rods on the bath surface. After discarding the supernatant therefrom by centrifuging at 4000rpm for 10 minutes, the precipitate therefrom was redispersed in 40ml of acetone and passed through a 10μm mesh filter to filter out foreign matter. After additional centrifugation (4000 rpm, 10 minutes), the precipitate was dried in a drying oven (100° C., 1 hour), and then weighed and dispersed in triethyl 2-acetyl citrate (TEC-Ac) at 0.05 w / w% to prepare an ink composition.

[0181] Example 2

[0182] An ink composition was prepared in the same manner as in Example 1, except that octyltrimethoxysilane (cas#: 3069-40-7, OD-CA, 1.5 mM solution in dodecane) was used as a ligand instead of hexyltrimethoxysilane.

[0183] Example 3

[0184] An ink composition was prepared in the same manner as in Example 1, except that ethyltrimethoxysilane (cas#: 5314-55-6, OD-CA, 1.5 mM solution in dodecane) was used as a ligand instead of hexyltrimethoxysilane.

[0185] Comparative Example 1

[0186] An ink composition was prepared in the same manner as in Example 1, except that no ligand was used.

[0187] The ligands used in Example 1 to Example 3 each had the following structure shown in Table 1.

[0188] [Table 1]

[0189]

[0190] Evaluate

[0191] The sedimentation rates of the ink compositions according to Examples 1 to 3 and Comparative Example 1 were measured by using Turbiscan, and then the sedimentation rates and dielectrophoretic properties were evaluated 8 hours after the measurement by using backscattering (BS) reduction rate and TSI (Turbiscan Stability Index) in Turbiscan, and the results are shown in Table 2.

[0192] [Table 2]

[0193]

[0194] Referring to Table 2, the ink composition including semiconductor nanorods surface-modified with a hydrophobic ligand in which the length and substituent of the alkyl group were controlled (Examples 1 to 3) exhibited an improved sedimentation rate and also exhibited excellent dielectrophoresis characteristics compared to the composition of Comparative Example 1.

[0195] While the disclosure has been described in conjunction with what are presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but on the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. An ink composition comprising: (A) a semiconductor nanorod comprising a functional group represented by Chemical Formula 1; and (B) Solvent: [Chemical formula 1] in, In Chemical Formula 1, R 1 and R 2 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, and R 3 is a substituted or unsubstituted C1 to C10 alkyl group.

2. The ink composition according to claim 1, wherein R 1 and R 2 Same, and R 3 With R 1 and R 2 different.

3. 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.

4. The ink composition according to claim 3, wherein R 3 is an unsubstituted C1 to C10 alkyl group.

5. The ink composition according to claim 4, wherein R 3 is an unsubstituted C1 to C8 alkyl group.

6. The ink composition according to claim 4, wherein R 3 is an unsubstituted C1 to C6 alkyl group.

7. The ink composition according to claim 4, wherein R 3 is an unsubstituted C2 to C6 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 includes a citrate-based compound.

16. The ink composition according to claim 1, wherein The ink composition 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. An ink composition comprising: (A) a semiconductor nanorod, the semiconductor nanorod being surface-modified with a surface-modifying material represented by Chemical Formula 2; and (B) Solvent: [Chemical formula 2] in, In chemical formula 2, R 1 , R 2 and R 4 are each independently a substituted or unsubstituted C1 to C20 alkoxy group, and R 3 is a substituted or unsubstituted C1 to C10 alkyl group.

19. A layer produced using the ink composition of claim 1.

20. An electrophoretic device comprising the layer of claim 19.

21. A display device comprising the layer of claim 19.

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