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

Abstract

Disclosed are an ink composition including (A) a semiconductor nanorod and (B) a solvent including a compound having a specific structure, in which the solvent has a conductivity of less than 2.0 [mu] S / m at 25 DEG C, a layer manufactured using the ink composition, and an electrophoretic apparatus and a display device each including the layer.

Description

Technical Field

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

[0002] LEDs have been actively developed since Nakamura et al. of Nichia Corporation of Japan successfully fused high-quality single-crystal GaN nitride semiconductors by applying a low-temperature GaN compound buffer layer in 1992. 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 bonded to each other.

[0003] This LED semiconductor has a high light conversion efficiency, so it consumes very little energy, has a semi-permanent lifespan, and is environmentally friendly, so it is called a revolution in light as a green material. Recently, with the development of compound semiconductor technology, high-brightness red, orange, green, blue and white LEDs have been developed and applied to many fields (such as traffic lights, mobile phones, car headlights, outdoor billboards, LCD BLU (backlight units) and indoor / outdoor lighting), and it has been actively studied at home and abroad. Specifically, 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 is being conducted on this.

[0004] Among these series of research, research on using ultra-small LED devices having a size in nanometer or micrometer units is being actively conducted, and research on utilizing these ultra-small LED devices in lighting and display is being continuously conducted. 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 for mounting ultra-small LED devices on the arranged electrodes, and the like continue to attract attention.

[0005] Among these, 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-sized or micro-sized, so it cannot be set and mounted one by one on the target electrode area 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 or InGaN-based compound semiconductors into rods, but there is a problem that the dispersion stability of the nanorods themselves in a solvent (or a polymerizable compound) is greatly deteriorated. So far, no technology has been introduced to improve the dispersion stability of semiconductor nanorods in a solvent (or a polymerizable compound). Therefore, research on an ink composition including semiconductor nanorods that can improve the dispersion stability of semiconductor nanorods in a solvent (or a polymerizable compound) and achieve a high dielectrophoretic rate is underway. 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 electrophoresis device comprising the layer.

[0011] Another embodiment provides a display device including the layer.

[0012] Technical Solution

[0013] The embodiment provides an ink composition including: (A) semiconductor nanorods; and (B) a solvent including a compound represented by Chemical Formula 1, wherein the solvent has a conductivity of less than 2.0 μS / m at 25° C.

[0014] [Chemical formula 1]

[0015]

[0016] In Chemical Formula 1,

[0017] R 1 is a hydrogen atom or *-C(=O)R' (wherein R' is a hydrogen atom or a substituted or unsubstituted C1 to C10 alkyl group),

[0018] R 2 To R 4 are independently substituted or unsubstituted C2 to C20 alkyl, and

[0019] L 1 and L 2 Each is independently a substituted or unsubstituted C1 to C20 alkylene group.

[0020] The solvent may have a dielectric constant (ε) of about 5 to about 10 at 25°C. r ).

[0021] The compound represented by Chemical Formula 1 may include a compound represented by Chemical Formula 1-1 or Chemical Formula 1-2.

[0022] [Chemical formula 1-1]

[0023]

[0024] [Chemical formula 1-2]

[0025]

[0026] The solvent may further include at least one compound having a structure different from that of the compound represented by Chemical Formula 1.

[0027] The solvent further including at least one compound having a structure different from that of the compound represented by Chemical Formula 1 may have an electrical conductivity of less than or equal to about 0.3 μS / m at 25° C.

[0028] The solvent may further include a compound represented by Chemical Formula 2.

[0029] [Chemical formula 2]

[0030]

[0031] In chemical formula 2,

[0032] R 5 and R 6 are independently a hydrogen atom or a substituted or unsubstituted C1 to C10 alkyl group, and

[0033] L 3 is a substituted or unsubstituted C1 to C20 alkylene group.

[0034] The solvent may further include the compound represented by Chemical Formula 3, the compound represented by Chemical Formula 4, or a combination thereof.

[0035] [Chemical formula 3]

[0036]

[0037] [Chemical formula 4]

[0038]

[0039] In Chemical Formula 3 and Chemical Formula 4,

[0040] R 7 and R 8 are independently a hydrogen atom or a substituted or unsubstituted C1 to C10 alkyl group, and

[0041] L 4 To L9 Each is independently a substituted or unsubstituted C1 to C20 alkylene group.

[0042] The solvent may further include the compound represented by Chemical Formula 5, the compound represented by Chemical Formula 6, the compound represented by Chemical Formula 7, or a combination thereof.

[0043] [Chemical formula 5]

[0044]

[0045] [Chemical formula 6]

[0046]

[0047] [Chemical formula 7]

[0048]

[0049] In Chemical Formulae 5 to 7,

[0050] R 9 To R 15 are independently a hydrogen atom or a substituted or unsubstituted C1 to C10 alkyl group, and

[0051] L 10 To L 12 Each is independently a substituted or unsubstituted C1 to C20 alkylene group.

[0052] The solvent may further include a compound represented by Chemical Formula 8.

[0053] [Chemical formula 8]

[0054]

[0055] In Chemical Formula 8,

[0056] R 16 and R 17 are independently a hydrogen atom or a substituted or unsubstituted C1 to C10 alkyl group, and

[0057] L 13 and L 14 Each is independently a substituted or unsubstituted C1 to C20 alkylene group.

[0058] In Chemical Formula 8, R 16 and R 17 may be independently substituted or unsubstituted C1 to C10 alkyl, and R 16 and R 17 Can be different from each other.

[0059] The semiconductor nanorods may have a diameter of about 300 nm to about 900 nm.

[0060] The semiconductor nanorods may have a length of about 3.5 μm to about 5 μm.

[0061] The semiconductor nanorods may include GaN-based compounds, InGaN-based compounds, or a combination thereof.

[0062] The semiconductor nanorods may have a surface coated with a metal oxide.

[0063] The metal oxide may include aluminum oxide, silicon dioxide, or a combination thereof.

[0064] 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.

[0065] The ink composition may further include: malonic acid; 3-amino-1,2-propanediol; a silane coupling agent; a leveling agent; a fluorine-based surfactant; or a combination thereof.

[0066] The ink composition may be an ink composition for an electrophoretic device.

[0067] Another embodiment provides a layer manufactured using the ink composition.

[0068] Another embodiment provides an electrophoresis device comprising the layer.

[0069] Another embodiment provides a display device including the layer.

[0070] Other embodiments of the invention are included in the detailed description below.

[0071] Beneficial Effects

[0072] The ink composition including the semiconductor nanorods according to the embodiment may have excellent electrophoretic characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 is an example of a cross-sectional view of a semiconductor nanorod used in an ink composition according to an embodiment. DETAILED DESCRIPTION

[0074] 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.

[0075] As used herein, when a specific definition is not otherwise provided, “alkyl” refers to a C1 to C20 alkyl group, “alkenyl” refers to a C2 to C20 alkenyl group, “cycloalkenyl” refers to a C3 to C20 cycloalkenyl group, “heterocycloalkenyl” refers to a C3 to C20 heterocycloalkenyl group, “aryl” refers to a C6 to C20 aryl group, “arylalkyl” refers to a C6 to C20 arylalkyl group, “alkylene” refers to a C1 to C20 alkylene group, “arylene” refers to a C6 to C20 arylene group, “alkylarylene” refers to a C6 to C20 alkylarylene group, “heteroarylene” refers to a C3 to C20 heteroarylene group, and “alkyleneoxy” refers to a C1 to C20 alkyleneoxy group.

[0076] As used herein, when a specific definition is not otherwise provided, “substituted” may refer to substitution with 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 phosphate group 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 to replace at least one hydrogen.

[0077] As used herein, when a specific definition is not otherwise provided, "hetero" may refer to a group substituted with at least one hetero atom among N, O, S and P in a chemical formula.

[0078] As used herein, when specific definitions are not otherwise provided, “(meth)acrylate” refers to both “acrylate” and “methacrylate”, and “(meth)acryl” refers to both “acryl” and “methacryl”.

[0079] As used herein, when no specific definition is otherwise provided, the term "combination" means mixing or copolymerization.

[0080] As used herein, unless a specific definition is otherwise provided, when a chemical bond is not drawn at a position where it should be given, a hydrogen atom is bonded at that position.

[0081] In this specification, a semiconductor nanorod refers to a rod-shaped semiconductor having a nanometer-sized diameter.

[0082] 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.

[0083] The ink composition according to the embodiment includes (A) semiconductor nanorods and (B) a solvent including a compound represented by Chemical Formula 1 and having a conductivity of less than 2.0 μS / m at 25° C.

[0084] [Chemical formula 1]

[0085]

[0086] In Chemical Formula 1,

[0087] R 1 is a hydrogen atom or *-C(=O)R' (wherein R' is a hydrogen atom or a substituted or unsubstituted C1 to C10 alkyl group),

[0088] R 2 To R 4 are independently substituted or unsubstituted C2 to C20 alkyl, and

[0089] L 1 and L 2 Each is independently a substituted or unsubstituted C1 to C20 alkylene group.

[0090] 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, the use of an electric field to align InGaN-based nanorod LEDs (electrophoresis) has attracted attention as a method of significantly reducing the complicated and expensive process costs of micro-LEDs, mini-LEDs, etc.

[0091] However, conventional organic solvents (PGMEA, GBL, PGME, ethyl acetate, IPA, diethylene glycol monophenyl ether, etc.) used for displays and electronic materials have low viscosity, so inorganic nanorod particles with high density may settle too quickly and thus agglomerate, and in addition, the organic solvent may volatilize quickly and thus may deteriorate the alignment characteristics during solvent drying after dielectrophoresis. Therefore, in order to develop an ink composition including inorganic nanorods (semiconductor nanorods), since a solvent having high viscosity and a high boiling point and thus excellent dielectrophoretic properties is required to improve the precipitation stability of the nanorods, the inventors, after repeated multiple trials and errors, significantly improved the dielectrophoretic properties of the semiconductor nanorods in the ink composition (specifically, simultaneously improved the center alignment and offset alignment) by including a compound represented by Chemical Formula 1 in a solvent used with the semiconductor nanorods while controlling the conductivity to be less than 2.0 μS / m at 25°C.

[0092] Hereinafter, each component is described in detail.

[0093] (A) Semiconductor Nanorods

[0094] 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.

[0095] The dispersion stability of the semiconductor nanorod ink solution (semiconductor nanorods + solvent) usually takes about 3 hours, which is extremely insufficient time for a large-area inkjet process. Therefore, after many trials and errors, the inventors coated the surface of the semiconductor nanorods with a metal oxide including aluminum oxide, silicon dioxide or a combination thereof to form an insulating layer (Al 2 O 3 or SiO x ), thereby maximizing compatibility with the solvent described later.

[0096] For example, the insulating layer coated with the metal oxide may have a thickness of about 40 nm to about 60 nm.

[0097] 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.

[0098] For example, the semiconductor nanorods can have a diameter of about 300 nm to about 900 nm (eg, about 600 nm to about 800 nm).

[0099] For example, the semiconductor nanorods may have a length of about 3.5 μm to about 5 μm.

[0100] 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.

[0101] For example, a semiconductor nanorod can have a -13 g to about 1×10 -11 The mass of g.

[0102] When the semiconductor nanorods have the above diameter, length, density, and type, surface coating of the metal oxide may be promoted, and dispersion stability of the semiconductor nanorods may be maximized.

[0103] Based on the total amount of the ink composition, the semiconductor nanorods may be included in an amount of about 0.01 wt % to about 10 wt % (e.g., about 0.01 wt % to about 5 wt %). Alternatively, based on 100 parts by weight of the solvent in the ink composition, the semiconductor nanorods may be included in an amount of about 0.01 parts by weight to about 0.5 parts by weight (e.g., about 0.01 parts by weight to about 0.1 parts by weight). 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.

[0104] (B) Solvent

[0105] The ink composition according to the embodiment includes a solvent having a conductivity of less than about 2.0 μS / m at 25° C. (eg, a conductivity of greater than or equal to about 0.1 μS / m and less than about 2.0 μS / m at 25° C.) while including the compound represented by Chemical Formula 1.

[0106] Recently, as the demand for nano-scale ultra-small LED devices has increased, attempts have been made to manufacture nano-scale GaN-based or InGaN-based compound semiconductors into rods, but there is a problem that the dispersion stability of the nanorods themselves in a solvent (or polymerizable compound) is greatly deteriorated. So far, no technology has been introduced to improve the dispersion stability of semiconductor nanorods in a solvent (or polymerizable compound).

[0107] Organic solvents (such as propylene glycol monomethyl ether acetate (PEGMEA), γ-butyrolactone (GBL), polyethylene glycol methyl ether (PGME), ethyl acetate, isopropyl alcohol (IPA), diethylene glycol monophenyl ether (DGPE), etc.) that have been used for 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. Therefore, as described above, in order to develop an ink composition for an electrophoresis device including inorganic nanorods (semiconductor nanorods), it is desirable to use a solvent that can impart nanorod precipitation stability.

[0108] Specifically, in order to improve storage stability and impart precipitation stability to the nanorods, the solvent should have a high viscosity at room temperature and should also have an appropriate dielectric constant and conductivity to ensure excellent dielectrophoretic properties.

[0109] When the nanorods are aligned in the ink composition by using an AC electric field, electrophoresis and dielectrophoresis occur simultaneously, so that the particles can be aligned in the correct direction (biased alignment) in the correct position (center alignment) on the substrate. Electrophoresis and dielectrophoresis are greatly affected by the dielectric constant and conductivity of the nanorods and the solvent. Since the electrical properties of the nanorods are almost similar, the alignment properties of the inkjet nanorods can be determined by the electrical properties of the solvent in which the nanorods are dispersed.

[0110] However, conventional materials (e.g., diethylene glycol monophenyl ether (DGPE)) exhibit a dielectric constant of about 9.4 and a conductivity of about 2.0 μS / m at about 25° C., wherein the alignment characteristics exhibit a center alignment of about 85% and a bias alignment of about 74%. Here, as a result of applying triethyl citrate having a relatively low dielectric constant (a dielectric constant of about 8.3 at about 25° C.) and a high conductivity (a conductivity of about 5.7 μS / m at about 25° C.), the center alignment is improved, but the bias alignment is significantly deteriorated.

[0111] Therefore, the inventors have confirmed that the bias alignment is more affected by the conductivity of the solvent, wherein the lower the conductivity, the more the bias alignment is improved, and in addition, when the solvent has a dielectric constant within a specific range, the center alignment is maintained at a similar level, and the present invention has been completed based on this finding after multiple experiments and repeated trials and errors. In other words, the inventors have found that when a solvent having too high a dielectric constant is used, the solvent other than the nanorods may be attracted to the electrode by the dielectrophoretic force, so that the nanorods are not well aligned, but when the solvent has too low a dielectric constant, the electric field of the ink composition becomes weak, weakening the force that attracts the nanorods, and confirmed that when an AC electric field is used to align the nanorods, by simultaneously controlling the dielectric constant and the conductivity in the solvent in the ink composition, the nanorods can be aligned in an excellent alignment shape, and in order to achieve a solvent having the above-mentioned characteristics, the center alignment and the bias alignment are simultaneously improved by controlling the solvent including the compound represented by Chemical Formula 1 to have a conductivity of less than about 2.0 μS / m at about 25°C.

[0112] For example, the solvent may have a dielectric constant (ε) of about 5 to about 10 at 25°C. r ) (e.g., a dielectric constant (ε) of about 5 to about 9 r ), for example, a dielectric constant (ε r ), for example, a dielectric constant (ε r )).

[0113] For example, the compound represented by Chemical Formula 1 may include a compound represented by Chemical Formula 1-1 or Chemical Formula 1-2, but is not necessarily limited thereto.

[0114] [Chemical formula 1-1]

[0115]

[0116] [Chemical formula 1-2]

[0117]

[0118] For example, the solvent may be a mixed solvent further including at least one compound having a structure different from that of the compound represented by Chemical Formula 1. In this case, it may be more desirable to improve both the center alignment degree and the offset alignment degree.

[0119] For example, the solvent further including at least one compound having a structure different from that of the compound represented by Chemical Formula 1 may have an electrical conductivity of less than or equal to about 0.3 μS / m at 25° C.

[0120] For example, the solvent may include the compound represented by Chemical Formula 1 and the compound represented by Chemical Formula 2.

[0121] [Chemical formula 2]

[0122]

[0123] In chemical formula 2,

[0124] R 5 and R 6 are independently a hydrogen atom or a substituted or unsubstituted C1 to C10 alkyl group, and

[0125] L 3 is a substituted or unsubstituted C1 to C20 alkylene group.

[0126] For example, the solvent may include the compound represented by Chemical Formula 3, the compound represented by Chemical Formula 4, or a combination thereof, and the compound represented by Chemical Formula 1.

[0127] For example, the solvent may include a compound represented by Chemical Formula 1, a compound represented by Chemical Formula 3, and a compound represented by Chemical Formula 4.

[0128] [Chemical formula 3]

[0129]

[0130] [Chemical formula 4]

[0131]

[0132] In Chemical Formula 3 and Chemical Formula 4,

[0133] R 7 and R 8 are independently a hydrogen atom or a substituted or unsubstituted C1 to C10 alkyl group, and

[0134] L 4 To L 9 Each is independently a substituted or unsubstituted C1 to C20 alkylene group.

[0135] For example, the solvent may include the compound represented by Chemical Formula 5, the compound represented by Chemical Formula 6, the compound represented by Chemical Formula 7, or a combination thereof as well as the compound represented by Chemical Formula 1.

[0136] For example, the solvent may include a compound represented by Chemical Formula 1, a compound represented by Chemical Formula 5, a compound represented by Chemical Formula 6, and a compound represented by Chemical Formula 7.

[0137] [Chemical formula 5]

[0138]

[0139] [Chemical formula 6]

[0140]

[0141] [Chemical formula 7]

[0142]

[0143] In Chemical Formulae 5 to 7,

[0144] R 9 To R 15 are independently a hydrogen atom or a substituted or unsubstituted C1 to C10 alkyl group, and

[0145] L 10 To L 12 Each is independently a substituted or unsubstituted C1 to C20 alkylene group.

[0146] For example, the solvent may further include a compound represented by Chemical Formula 8.

[0147] [Chemical formula 8]

[0148]

[0149] In Chemical Formula 8,

[0150] R 16 and R 17 are independently a hydrogen atom or a substituted or unsubstituted C1 to C10 alkyl group, and

[0151] L 13 and L 14 Each is independently a substituted or unsubstituted C1 to C20 alkylene group.

[0152] For example, in Formula 8, R 16 and R 17 may be independently substituted or unsubstituted C1 to C10 alkyl, and R 16 and R 17 Can be different from each other.

[0153] For example, the solvent may include the compound represented by Chemical Formula 1 and the compound represented by Chemical Formula 8.

[0154] For example, the solvent may include a compound represented by Chemical Formula 1, a compound represented by Chemical Formula 2, and a compound represented by Chemical Formula 8.

[0155] For example, the solvent may include a compound represented by Chemical Formula 1, a compound represented by Chemical Formula 3, a compound represented by Chemical Formula 4, and a compound represented by Chemical Formula 8.

[0156] For example, the solvent may include a compound represented by Chemical Formula 1, a compound represented by Chemical Formula 5, a compound represented by Chemical Formula 6, a compound represented by Chemical Formula 7, and a compound represented by Chemical Formula 8.

[0157] The solvent may be included in an amount of about 15 wt % to about 99.99 wt % (eg, about 20 wt % to about 99.7 wt %) based on the total amount of the ink composition.

[0158] Polymerizable monomer

[0159] The ink composition according to the embodiment may further include a polymerizable compound. The polymerizable compound may be used by mixing a monomer or an oligomer generally used in a conventional curable composition.

[0160] For example, the polymerizable compound may be a polymerizable monomer having a carbon-carbon double bond at its terminal.

[0161] 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 a terminal thereof.

[0162] [Chemical formula A-1]

[0163]

[0164] [Chemical formula A-2]

[0165]

[0166] In Chemical Formula A-1 and Chemical Formula A-2,

[0167] L 15 is a substituted or unsubstituted C1 to C20 alkylene group, and

[0168] R 18 is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group.

[0169] The polymerizable compound includes 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.

[0170] 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.

[0171] 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 DPCA-20 of Nippon Chemical Co., Ltd., KAYARAD DPCA-30, KAYARAD DPCA-60, KAYARAD DPCA-120 or KAYARAD DPEA-12 or a combination thereof, but not necessarily limited thereto.

[0172] The polymerizable compound may be used after being treated with an acid anhydride to impart better developability.

[0173] Polymerization initiator

[0174] The ink composition according to an embodiment may further include a polymerization initiator (eg, a photopolymerization initiator, a thermal polymerization initiator, or a combination thereof).

[0175] The photopolymerization initiator may be a commonly used initiator for a curable composition, and may be, for example, acetophenone compounds, benzophenone compounds, thioxanthone compounds, benzoin compounds, triazine compounds, oxime compounds, aminoketone compounds, etc., but is not necessarily limited thereto.

[0176] Examples of acetophenone compounds include 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.

[0177] Examples of benzophenone compounds include benzophenone, benzoyl benzoate, benzoyl benzoate methyl ester, 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.

[0178] Examples of the thioxanthone-based compound may include thioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 2-chlorothioxanthone, and the like.

[0179] Examples of the benzoin-based compound include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, and the like.

[0180] Examples of the triazine 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, and 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-(naphthalene-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxynaphthalene-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.

[0181] Examples of oxime compounds include O-acyloxime compounds, 2-(O-benzoyloxime)-1-[4-(phenylthio)phenyl]-1,2-octanedione, 1-(O-acetyloxime)-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-acyloximine compounds can be 1,2-octanedione, 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl)-butane-1-one, 1-(4-phenylsulfanylphenyl)-butane-1,2-dione-2-oxime-O-benzoate, 1-(4-phenylsulfanylphenyl)-octane-1,2-dione-2-oxime-O-benzoate, 1-(4-phenylsulfanylphenyl)-octane-1-one oxime-O-acetate, 1-(4-phenylsulfanylphenyl)-butane-1-one oxime-O-acetate, and the like.

[0182] Examples of aminoketone compounds include 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butane-1-one and the like.

[0183] In addition to the above compounds, the photopolymerization initiator may further include carbazole compounds, diketone compounds, sulfonium borate compounds, diazo compounds, imidazole compounds, biimidazole compounds, and the like.

[0184] The photopolymerization initiator may be used together with a photosensitizer that is capable of causing a chemical reaction by absorbing light and being excited and then transferring its energy.

[0185] Examples of the photosensitizer may include tetraethylene glycol bis-3-mercaptopropionate, pentaerythritol tetrakis-3-mercaptopropionate, dipentaerythritol tetrakis-3-mercaptopropionate, and the like.

[0186] Examples of thermal polymerization initiators may include peroxides (specifically, benzoyl peroxide, dibenzoyl peroxide, lauroyl peroxide, dilauroyl peroxide, di-tert-butyl peroxide, cyclohexane peroxide, methyl ethyl ketone peroxide), oxides, hydroperoxides (e.g., tert-butyl hydroperoxide, cumene hydroperoxide, etc.), dicyclohexyl peroxydicarbonate, 2,2-azo-bis(isobutyronitrile), tert-butyl perbenzoate, 2,2'-azo-bis-2-methylpropionitrile, and the like, but are not necessarily limited thereto, and any one widely known in the art may be used.

[0187] The polymerization initiator may be included in an amount of about 1 wt % to about 5 wt % (e.g., 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 thermal curing.

[0188] Other additives

[0189] The ink composition according to the embodiment may further include a polymerization inhibitor including a hydroquinone compound, a catechol compound, or a combination thereof. Since the ink composition according to the embodiment also includes a hydroquinone compound, a catechol compound, or a combination thereof, crosslinking at room temperature may be prevented during exposure after printing (coating) the ink composition.

[0190] For example, the hydroquinone compound, the catechol 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-nitrosoanilino-O,O′)aluminum or a combination thereof, but are not necessarily limited thereto.

[0191] The hydroquinone compound, the catechol 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 % (e.g., 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 problem of aging over time at room temperature may be solved, and at the same time, sensitivity degradation and surface delamination phenomena may be suppressed.

[0192] 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.

[0193] For example, in order to improve the close contact property with the substrate, the ink composition may further include a silane-based coupling agent having a reactive substituent such as a vinyl group, a carboxyl group, a methacryloxy group, an isocyanate group, an epoxy group, etc.

[0194] Examples of the silane coupling agent may be trimethoxysilylbenzoic acid, γ-methacryloylpropoxytrimethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, γ-isocyanatepropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, β-epoxycyclohexylethyltrimethoxysilane, and the like, and these may be used alone or in mixture of two or more.

[0195] 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 properties, storage ability, and the like are improved.

[0196] In addition, 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.

[0197] Examples of fluorinated surfactants include BM Chemie Inc. etc.; MEGAFACE F from Dainippon Ink Kagaku Kogyo Co., Ltd. MEGAFACE F MEGAFACE F MEGAFACE F etc.; FULORAD of Sumitomo3M 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.

[0198] 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 do not occur, and wettability to a glass substrate is excellent.

[0199] In addition, unless the properties are deteriorated, the ink composition may further include other additives (such as an antioxidant, a stabilizer, etc.) in a predetermined amount.

[0200] Another embodiment provides a layer using an ink composition.

[0201] Another embodiment provides a display device comprising the layer. For example, the display device may be an electrophoretic device.

[0202] Invention method

[0203] Hereinafter, the present invention is illustrated in more detail with reference to examples. However, these examples should not be interpreted as limiting the scope of the present invention in any sense.

[0204] (Preparation of ink composition)

[0205] Examples 1 to 4 and Comparative Examples 1 and 2

[0206] 40mL of stearic acid (1.5mM) was reacted on a nanorod patterned InGaN wafer (4 inches) at room temperature for 24 hours. After the reaction, the wafer was immersed in 50mL of acetone for 5 minutes to remove excess stearic acid, and the surface of the wafer was rinsed with 40mL of acetone in addition. The cleaned wafer was placed in a 27kW bath-type sonicator together with 35mL of GBL, and then sonicated for 5 minutes to separate the rods from the wafer surface. The separated rods were placed in a FALCON tube for centrifugation, and 10mL of GBL was added thereto to additionally wash the rods on the bath surface. After discarding the supernatant by centrifugation at 4000rpm for 10 minutes, the precipitate thus obtained was redispersed in 40mL of acetone, and then foreign matter was filtered out through a 10μm mesh filter. After additional centrifugation (4000 rpm, 10 minutes), the precipitate was dried in a drying oven (100° C., 1 hour), then weighed and dispersed to 0.05 w / w % to prepare an ink composition having the components shown in Table 1.

[0207] (The composition of the mixed solvent and the dielectric constant and conductivity of the solvent at 25°C are shown in Table 2.)

[0208] (Table 1)

[0209] (Unit: wt%)

[0210]

[0211] (Table 2)

[0212]

[0213] Evaluation: Electrophoretic properties

[0214] 500 μL of each ink composition according to Examples 1 to 4 and Comparative Examples 1 and 2 was coated on a thin film gold basic interdigitated linear electrode (ED-cIDE4-Au, MicruX Technologies), and after applying an electric field (25 kHz, ±30 V) thereto, it was left for 1 minute. After the solvent was dried by using a hot plate, the electrophoretic properties of each ink composition were evaluated by checking the number of aligned rods (ea) and the number of misaligned rods (ea) at the center between the electrodes using a microscope, and the results are shown in Table 3.

[0215] (Table 3)

[0216] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Center alignment (%) 91 92 94 89 85 93 Offset alignment (%) 90 96 94 98 74 51

[0217] As shown in Table 3, compared with Comparative Examples 1 and 2, Examples 1 to 4 simultaneously exhibited significantly improved center alignment and offset alignment (the center alignment and offset alignment were improved to 89% or more, respectively), which proves to be suitable for large-area coating and panel production.

[0218] Although the invention has been described in conjunction with what are currently considered to be practical example embodiments, it will be understood that the invention is not limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Therefore, the foregoing embodiments should be understood as examples and not limiting the present invention in any way.

Claims

1. An ink composition, comprising: (A) Semiconductor nanorods; as well as (B) a solvent including a compound represented by Chemical Formula 1, Wherein, the solvent has a conductivity of less than 2.0 μS / m at 25°C: [Chemical formula 1] Wherein, in Chemical Formula 1, R 1 is a hydrogen atom or *-C(=O)R', wherein R' is a hydrogen atom or a substituted or unsubstituted C1 to C10 alkyl group, R 2 To R 4 are independently substituted or unsubstituted C2 to C20 alkyl, and L 1 and L 2 Each is independently a substituted or unsubstituted C1 to C20 alkylene group.

2. The ink composition according to claim 1, wherein The solvent has a dielectric constant (ε) of 5 to 10 at 25°C. r ).

3. The ink composition according to claim 1, wherein The compound represented by Chemical Formula 1 includes a compound represented by Chemical Formula 1-1 or Chemical Formula 1-2: [Chemical formula 1-1] [Chemical formula 1-2] 4. The ink composition according to claim 1, wherein The solvent further includes at least one compound having a structure different from that of the compound represented by Chemical Formula 1.

5. The ink composition according to claim 4, wherein The solvent further including at least one compound having a structure different from that of the compound represented by Chemical Formula 1 has an electrical conductivity of less than or equal to 0.3 μS / m at 25° C.

6. The ink composition according to claim 4, wherein The solvent also includes a compound represented by Chemical Formula 2: [Chemical formula 2] Wherein, in Chemical Formula 2, R 5 and R 6 are independently a hydrogen atom or a substituted or unsubstituted C1 to C10 alkyl group, and L 3 is a substituted or unsubstituted C1 to C20 alkylene group.

7. The ink composition according to claim 4, wherein The solvent further includes a compound represented by Chemical Formula 3, a compound represented by Chemical Formula 4, or a combination thereof: [Chemical formula 3] [Chemical formula 4] Among them, in Chemical Formula 3 and Chemical Formula 4, R 7 and R 8 are independently a hydrogen atom or a substituted or unsubstituted C1 to C10 alkyl group, and L 4 To L 9 Each is independently a substituted or unsubstituted C1 to C20 alkylene group.

8. The ink composition according to claim 4, wherein The solvent further includes a compound represented by Chemical Formula 5, a compound represented by Chemical Formula 6, a compound represented by Chemical Formula 7, or a combination thereof: [Chemical formula 5] [Chemical formula 6] [Chemical formula 7] Among them, in Chemical Formula 5 to Chemical Formula 7, R 9 To R 15 are independently a hydrogen atom or a substituted or unsubstituted C1 to C10 alkyl group, and L 10 To L 12 Each is independently a substituted or unsubstituted C1 to C20 alkylene group.

9. The ink composition according to claim 4, wherein The solvent also includes a compound represented by Chemical Formula 8: [Chemical formula 8] Among them, in chemical formula 8, R 16 and R 17 are independently a hydrogen atom or a substituted or unsubstituted C1 to C10 alkyl group, and L 13 and L 14 Each is independently a substituted or unsubstituted C1 to C20 alkylene group.

10. The ink composition according to claim 9, wherein R 16 and R 17 are independently substituted or unsubstituted C1 to C10 alkyl, and R 16 and R 17 Different from each other.

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

12. The ink composition according to claim 1, wherein The semiconductor nanorods have a length of 3.5 μm to 5 μm.

13. The ink composition according to claim 1, wherein The semiconductor nanorods include GaN compounds, InGaN compounds or a combination thereof.

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

15. The ink composition according to claim 14, wherein The metal oxide includes aluminum oxide, silicon dioxide or a combination thereof.

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

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

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

19. An electrophoretic device comprising a layer according to claim 18.

20. A display device comprising a layer according to claim 18.

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