Ink composition, layers using it, electrophoresis apparatus, and display device.

Abstract

An ink composition, a layer manufactured using the ink composition, and an electrophoresis apparatus and display device including the ink composition are provided. The ink composition comprises (A) semiconductor nanorods and (B) a mixed solvent, the mixed solvent comprising a first solvent and a second solvent, the first solvent comprising a compound represented by chemical formula 1, and the second solvent comprising a compound represented by chemical formula 2. The definitions of chemical formula 1 and chemical formula 2 are the same as in the specification. The ink composition may exhibit excellent dielectric properties and storage stability.

Description

Technical Field

[0001] This disclosure relates to an ink composition, a layer using the same, an electrophoresis apparatus, and a display device including the layer. Background Technology

[0002] Since 1992, when Nakamura et al. of Japanese Nichia Corp. successfully fused high-quality single-crystal GaN nitride semiconductors using a low-temperature GaN compound buffer layer, light-emitting diodes (LEDs) have been actively developed. An LED is a semiconductor device that utilizes the properties of compound semiconductors to convert electrical signals into light with wavelengths in a desired region. It has a structure in which an n-type semiconductor crystal, in which multiple carriers are electrons, is bonded to a p-type semiconductor crystal, in which multiple carriers are holes.

[0003] This type of LED semiconductor boasts high light conversion efficiency, thus consuming minimal energy and possessing a semi-permanent lifespan. Furthermore, it is environmentally friendly, earning it the title of a "light revolution" 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 in numerous fields, including traffic lights, mobile phones, car headlights, outdoor billboards, liquid crystal display backlight units (LCD BLUs), and indoor / outdoor lighting. This has been actively researched both domestically and internationally. Specifically, GaN-based compound semiconductors with wide bandgap are used to manufacture LED semiconductors that emit light in the green, blue, and ultraviolet (UV) regions. Extensive research has been conducted on using blue LED devices to manufacture white LED devices.

[0004] In these studies, research is actively underway on ultra-miniature LED devices with dimensions of nanometers or micrometers, and further research is ongoing on their application in light emission and displays. In these studies, the electrodes capable of applying power to the ultra-miniature LED devices, electrode arrangement methods to reduce the space occupied by the electrodes, and methods for mounting the ultra-miniature LED devices on the arranged electrodes are attracting increasing attention.

[0005] However, due to the size limitations of ultra-miniature LED devices, the method of mounting ultra-miniature LED devices on the electrodes still faces difficulties in achieving the desired setup and installation. This is because ultra-miniature LED devices are at the nanometer or micrometer scale, and therefore cannot be manually set and installed one by one on the target electrode area.

[0006] Recently, with the increasing demand for nanoscale ultra-miniature LED devices, attempts have been made to fabricate nanoscale GaN-based or InGaN-based compound semiconductors into rods. However, the dispersion stability of the nanorods themselves in solvents (or polymerizable compounds) can be significantly reduced. Furthermore, to date, no technology has been introduced to improve the dispersion stability of semiconductor nanorods in solvents (or polymerizable compounds). Therefore, research on curable compositions including semiconductor nanorods to improve the dispersion stability of semiconductor nanorods in solvents (or polymerizable compounds) and achieve high dielectrophoresis rates continues. Summary of the Invention

[0007] Technical challenges

[0008] The embodiment provides an ink composition with excellent dielectric properties and storage stability of semiconductor nanorods.

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

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

[0011] Problem-solving methods

[0012] An embodiment provides an ink composition comprising (A) semiconductor nanorods; and (B) a mixed solvent comprising a first solvent and a second solvent, the first solvent comprising a compound represented by chemical formula 1 and the second solvent comprising a compound represented by chemical formula 2.

[0013] [Chemical Formula 1]

[0014]

[0015] In chemical formula 1,

[0016] R 1 To R 3 Each is independently a hydrogen atom or a C1 to C10 alkyl group.

[0017] R 4 It is a hydrogen atom or *-C(=O)R 5 , where R 5It is a C1 to C10 alkyl group.

[0018] L 1 and L 2 Each is independently a substituted or unsubstituted C1 to C20 alkyl or a substituted or unsubstituted C6 to C20 aryl, and

[0019] L 3 It can be *-O-*, *-S-*, or *-NH-*, where * is a connection point.

[0020] [Chemical Formula 2]

[0021]

[0022] In chemical formula 2,

[0023] R 6 and R 7 Each is independently a hydrogen atom, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, or a substituted or unsubstituted C6 to C20 aryl group, and

[0024] R 8 and R 9 Each is independently a hydrogen atom or *-(C=O)R 10 , where R 10 It is a substituted or unsubstituted C1 to C20 alkyl, a substituted or unsubstituted C3 to C20 cycloalkyl, or a substituted or unsubstituted C6 to C20 aryl, and * is the connecting point.

[0025] Chemical formula 2 can be represented by chemical formula 2A.

[0026] [Chemical Formula 2A]

[0027]

[0028] In chemical formula 2A,

[0029] R 6 and R 7 Each is independently a hydrogen atom, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, or a substituted or unsubstituted C6 to C20 aryl group, and

[0030] R 8 and R 9 Each is independently a hydrogen atom or *-(C=O)R 10 , where R 10It is a substituted or unsubstituted C1 to C20 alkyl, a substituted or unsubstituted C3 to C20 cycloalkyl, or a substituted or unsubstituted C6 to C20 aryl, and * is the connecting point.

[0031] In chemical formula 2 or chemical formula 2A, R 8 and R 9 Each can be an independent hydrogen atom.

[0032] In chemical formula 2 or chemical formula 2A, R 6 and R 7 Each can be an independent hydrogen atom.

[0033] Compounds represented by chemical formula 2 may include compounds represented by any of chemical formulas 2-1 to 2-4.

[0034] [Chemical Formula 2-1]

[0035]

[0036] [Chemical Formula 2-2]

[0037]

[0038] [Chemical Formula 2-3]

[0039]

[0040] [Chemical Formula 2-4]

[0041]

[0042] Compounds represented by chemical formula 2A may include compounds represented by any of chemical formulas 2A-1 to 2A-4.

[0043] [Chemical Formula 2A-1]

[0044]

[0045] [Chemical Formula 2A-2]

[0046]

[0047] [Chemical Formula 2A-3]

[0048]

[0049] [Chemical Formula 2A-4]

[0050]

[0051] The first solvent and the second solvent can be mixed in a weight ratio of 1:1 to 1:3. For example, when the mixed solvent consists of the first solvent and the second solvent, the first solvent and the second solvent can be mixed in a weight ratio of 1:1 to 1:3.

[0052] The mixed solvent may also include a third solvent comprising a compound represented by chemical formula 3.

[0053] [Chemical Formula 3]

[0054]

[0055] In chemical formula 3,

[0056] R 11 To R 13 Each is independently a substituted or unsubstituted C1 to C20 alkoxy group.

[0057] In chemical formula 3, R 11 To R 13 Each can be independently a C1 to C20 alkoxy group with or without C2 to C10 alkenyl substitution.

[0058] The first solvent may be included in an amount of 100 to 1600 parts by weight based on 100 parts by weight of the second solvent, and the third solvent may be included in an amount of 50 to 900 parts by weight based on 100 parts by weight of the second solvent.

[0059] The mixed solvent may consist of a first solvent, a second solvent, and a third solvent, wherein the sum of the amounts of the first solvent and the second solvent may be greater than the amount of the third solvent, and the sum of the amounts of the first solvent and the third solvent may be greater than the amount of the second solvent.

[0060] The mixed solvent may consist of a first solvent, a second solvent, and a third solvent, wherein the sum of the amounts of the second solvent and the third solvent may be greater than the amount of the first solvent.

[0061] The mixed solvent may consist of a first solvent, a second solvent, and a third solvent, wherein the sum of the amounts of the second solvent and the third solvent may be less than the amount of the first solvent.

[0062] The semiconductor nanorods may have a diameter of 300 nanometers to 900 nanometers.

[0063] The semiconductor nanorods can have a length of 3.5 micrometers to 5 micrometers.

[0064] The semiconductor nanorods may comprise GaN-based compounds, InGaN-based compounds, or combinations thereof.

[0065] The semiconductor nanorod may have a surface coated with a metal oxide.

[0066] The metal oxide may include aluminum oxide, silicon dioxide, or a combination thereof.

[0067] The semiconductor nanorods may be contained in an amount from 0.01% to 10% by weight, based on the total amount of ink composition.

[0068] The ink composition may further include malonic acid; 3-amino-1,2-propanediol; silane coupling agent; leveling agent; fluorine surfactant; or a combination thereof.

[0069] The ink composition may be an ink composition used in electrophoresis apparatus.

[0070] Another embodiment provides a layer manufactured using the ink composition.

[0071] Another embodiment provides an electrophoresis apparatus including the said layer.

[0072] Another embodiment provides a display device including the layer.

[0073] Other embodiments of the invention are included in the following detailed description.

[0074] Invention Effects

[0075] The ink composition containing semiconductor nanorods according to the embodiments can be a curable composition with excellent dielectric properties and storage stability. Attached Figure Description

[0076] Figure 1 This is an example of a cross-sectional view of a semiconductor nanorod used in a curable composition according to an embodiment. Detailed Implementation

[0077] Embodiments of the invention are described in detail below. However, these embodiments are exemplary, and the invention is not limited thereto, and the scope of the claims defines the invention.

[0078] As used herein, unless otherwise specifically defined, “alkyl” refers to C1 to C20 alkyl, “alkenyl” refers to C2 to C20 alkenyl, “cycloalkenyl” refers to C3 to C20 cycloalkenyl, “heterocyclic alkenyl” refers to C3 to C20 heterocyclic alkenyl, “aryl” refers to C6 to C20 aryl, “arylalkyl” refers to C6 to C20 arylalkyl, “extrinalkyl” refers to C1 to C20 exrinalkyl, “extrinaryl” refers to C6 to C20 exrinaryl, “alkylextrinaryl” refers to C6 to C20 alkylextrinaryl, “extrinheteroaryl” refers to C3 to C20 exrinheteroaryl, and “extrinalkoxy” refers to C1 to C20 exrinalkoxy.

[0079] As used herein, unless otherwise specifically defined, “substituted” means that at least one hydrogen atom is replaced by one of the following: a halogen atom (F, Cl, Br or I), a hydroxyl group, a C1 to C20 alkoxy group, a nitro group, a cyano group, an amino group, an imino group, an azide group, an amido group, a hydrazine group, a hydrazone group, a carbonyl 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 heterocyclic alkyl group, a C2 to C20 heterocyclic alkenyl group, a C2 to C20 heterocyclic alkynyl group, a C3 to C20 heteroaryl group, or a combination thereof.

[0080] As used herein, unless otherwise specifically defined, “heterogeneous” means a group in a chemical formula that includes at least one heteroatom selected from N, O, S and P.

[0081] As used herein, unless otherwise specifically defined, “(meth)acrylate” means both “acrylate” and “methacrylate”, and “(meth)acrylic acid” means both “acrylic acid” and “methacrylic acid”.

[0082] As used in this article, unless otherwise defined, the term "combination" refers to a mixture or copolymer.

[0083] As used herein, unless otherwise specifically defined, a hydrogen atom is bonded at the location where a chemical bond should be drawn.

[0084] As used in this article, "semiconductor nanorod" refers to a rod-shaped semiconductor with a diameter of nanometer size.

[0085] As used herein, unless otherwise defined, "*" indicates a point connecting identical or different atoms or chemical formulas.

[0086] The ink composition according to the embodiment includes (A) semiconductor nanorods; and (B) a mixed solvent comprising a first solvent and a second solvent, the first solvent comprising a compound represented by chemical formula 1 and the second solvent comprising a compound represented by chemical formula 2.

[0087] [Chemical Formula 1]

[0088]

[0089] In chemical formula 1,

[0090] R1 to R3 are each independently a hydrogen atom or a C1 to C10 alkyl group.

[0091] R4 is a hydrogen atom or *-C(=O)R5, where R5 is a C1 to C10 alkyl group.

[0092] L1 and L2 are each independently a substituted or unsubstituted C1 to C20 alkyl or a substituted or unsubstituted C6 to C20 aryl, and

[0093] L3 is *-O-*, *-S-*, or *-NH-*.

[0094] [Chemical Formula 2]

[0095]

[0096] In chemical formula 2,

[0097] R6 and R7 are each independently a hydrogen atom, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, or a substituted or unsubstituted C6 to C20 aryl group, and

[0098] R8 and R9 are each independently a hydrogen atom or *-(C=O)R10, wherein R10 is a substituted or unsubstituted C1 to C20 alkyl, a substituted or unsubstituted C3 to C20 cycloalkyl, or a substituted or unsubstituted C6 to C20 aryl.

[0099] Recently, research has been actively conducted on various concepts that can improve the energy efficiency of conventional LEDs, such as micro LEDs, miniature LEDs, and similar LEDs, and prevent the efficiency degradation of these conventional LEDs. Among these, the alignment (electrophoresis) of InGaN-based nanorod LEDs using an electric field has attracted attention as a method to significantly reduce the complexity and expensive manufacturing costs of micro LEDs, miniature LEDs, and similar LEDs.

[0100] However, the organic solvents traditionally used in displays and electronic materials (propylene glycol monomethyl ether acetate (PGMEA), gamma-butyrolactone (GBL), polyethylene glycol methyl ether (PGME), ethyl acetate, isopropyl alcohol (IPA), and the like) have low viscosity, and therefore the high-density inorganic nanorod particles may settle too quickly and thus agglomerate. In addition, the organic solvents may evaporate rapidly and thus the alignment properties may deteriorate during solvent drying after dielectrophoresis. Therefore, in order to develop ink compositions containing inorganic material nanorods (semiconductor nanorods), solvents with excellent dielectric properties due to their high viscosity, low dielectric constant, and conductivity are needed to improve the sedimentation stability of the nanorods. After numerous experiments, the inventors of this invention have significantly improved the dielectric properties of the semiconductor nanorods in the ink composition while maintaining the inkjet properties of the ink composition. Furthermore, excellent storage stability has been achieved by mixing compounds with specific structures as solvents for the semiconductor nanorods.

[0101] The components will be described in detail below.

[0102] (A) Semiconductor nanorods

[0103] Semiconductor nanorods may contain GaN-based compounds, InGaN-based compounds, or combinations thereof, and their surfaces may be coated with metal oxides.

[0104] To ensure the dispersion stability of semiconductor nanorod ink solutions (semiconductor nanorods + solvent), a typical process takes 3 hours, which is insufficient for large-area inkjet printing. Therefore, after numerous experiments, the inventors of this invention have developed an insulating film (Al2O3 or SiOx) by coating the surface of semiconductor nanorods with metal oxides (e.g., aluminum oxide, silicon dioxide, or combinations thereof) to maximize compatibility with the solvents described below.

[0105] For example, an insulating film coated with a metal oxide can have a thickness of 40 nanometers to 60 nanometers.

[0106] The semiconductor nanorod includes an n-type confinement layer and a p-type confinement layer, and the active region of the multi-quantum well (MQW) can be disposed between the n-type confinement layer and the p-type confinement layer.

[0107] For example, semiconductor nanorods can have a diameter of 300 nanometers to 900 nanometers, such as 600 nanometers to 700 nanometers.

[0108] For example, semiconductor nanorods can have lengths ranging from 3.5 micrometers to 5 micrometers.

[0109] For example, when semiconductor nanorods may include an alumina insulating layer, they may have a density of 5 g / cm³ to 6 g / cm³.

[0110] For example, semiconductor nanorods can have a mass of 1×10⁻¹³ grams to 1×10⁻¹¹ grams.

[0111] When semiconductor nanorods have the aforementioned diameter, length, density, and type, surface coating with metal oxides can be easily performed, thereby maximizing the dispersion stability of the semiconductor nanorods.

[0112] Semiconductor nanorods may be included in an amount from 0.01 wt% to 10 wt%, for example, from 0.01 wt% to 5 wt%, based on the total amount of the ink composition. Alternatively, semiconductor nanorods may be included in an amount from 0.01 wt% to 0.5 wt%, for example, from 0.01 wt% to 0.1 wt%, based on 100 parts by weight of solvent in the ink composition. When semiconductor nanorods are included within the above range, they exhibit good dispersibility in the ink, and the prepared pattern can have excellent brightness.

[0113] (B) Solvent

[0114] The ink composition according to the embodiment includes a mixed solvent, the mixed solvent comprising a first solvent and a second solvent, the first solvent comprising a compound represented by chemical formula 1 and the second solvent comprising a compound represented by chemical formula 2.

[0115] In recent years, with the increasing demand for nanoscale micro-LED devices, attempts have been made to fabricate nanoscale GaN-based or InGaN-based compound semiconductors into rods. However, nanorods themselves suffer from significantly deteriorated dispersion stability in solvents (or polymerizable compounds). To date, no technology has been introduced to improve the dispersion stability of semiconductor nanorods in solvents.

[0116] To ensure high viscosity / high dielectric constant of ink compositions used for inkjet printing, compounds such as 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, or similar compounds are typically used as solvents. However, these solvents exhibit poor compatibility with citric acid-based or triazine-based solvents, leading to deterioration in low-temperature storage stability and precipitation problems when mixed solvents are used to prepare ink compositions. Therefore, the inventors have solved these problems by including a compound represented by Formula 2 in the mixed solvent, which significantly improves the compatibility of the solvent with citric acid-based and triazine-based solvents, while also providing improved dielectric properties and low-temperature storage stability.

[0117] For example, chemical formula 2 can be represented by chemical formula 2A.

[0118] [Chemical Formula 2A]

[0119]

[0120] In chemical formula 2A,

[0121] R6 and R7 are each independently a hydrogen atom, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, or a substituted or unsubstituted C6 to C20 aryl group, and

[0122] R8 and R9 are each independently a hydrogen atom or *-(C=O)R10, wherein R10 is a substituted or unsubstituted C1 to C20 alkyl, a substituted or unsubstituted C3 to C20 cycloalkyl, or a substituted or unsubstituted C6 to C20 aryl.

[0123] For example, in chemical formula 2 and / or chemical formula 2A, R8 and R9 can each be hydrogen atoms independently. In this case, the compatibility of the second solvent with the first and third solvents, which will be described later, can be further improved.

[0124] For example, in chemical formula 2 and / or chemical formula 2A, R6 and R7 can each be hydrogen atoms independently. In this case, the compatibility of the second solvent with the first and third solvents, which will be described later, can be further improved.

[0125] For example, in formula 2 and / or formula 2A, R6 to R9 can each be a hydrogen atom independently. In this case, the compatibility of the second solvent with the first and third solvents, which will be described later, can be maximized.

[0126] Compounds represented by chemical formula 2 may include, but are not limited to, compounds represented by any of chemical formulas 2-1 to 2-4.

[0127] [Chemical Formula 2-1]

[0128]

[0129] [Chemical Formula 2-2]

[0130]

[0131] [Chemical Formula 2-3]

[0132]

[0133] [Chemical Formula 2-4]

[0134]

[0135] For example, a compound represented by chemical formula 2A may include, but is not limited to, compounds represented by any of chemical formulas 2A-1 to 2A-4.

[0136] [Chemical Formula 2A-1]

[0137]

[0138] [Chemical Formula 2A-2]

[0139]

[0140] [Chemical Formula 2A-3]

[0141]

[0142] [Chemical Formula 2A-4]

[0143]

[0144] For example, the first solvent and the second solvent can be mixed in a weight ratio of 1:1 to 1:3. For example, when the mixed solvent consists of the first solvent and the second solvent, the first solvent and the second solvent can be mixed in a weight ratio of 1:1 to 1:3. When the mixed solvent consists of the first solvent and the second solvent, if the mixing weight ratio of the first solvent and the second solvent is controlled within the above range, the compatibility of the first solvent and the second solvent can be further improved.

[0145] The mixed solvent may also include compounds represented by chemical formula 3.

[0146] [Chemical Formula 3]

[0147]

[0148] In chemical formula 3,

[0149] R11 to R13 are each independently a substituted or unsubstituted C1 to C20 alkoxy group.

[0150] For example, in Formula 3, R11 to R13 may each be independently a C1 to C20 alkoxy group substituted with a C2 to C10 alkenyl group (e.g., vinyl group, etc.) or unsubstituted with a C2 to C10 alkenyl group.

[0151] When the mixed solvent in the ink composition according to the embodiment includes a third solvent in addition to the first solvent and the second solvent, the compatibility between solvents with different structures can be further improved, and thus the storage stability at low temperatures can be maximized.

[0152] For example, a compound represented by chemical formula 3 may include at least one compound selected from those represented by chemical formula 3-1 and chemical formula 3-2, but is not necessarily limited to this.

[0153] [Chemical Formula 3-1]

[0154]

[0155] [Chemical Formula 3-2]

[0156]

[0157] For example, when the mixed solvent consists of a first solvent, a second solvent and a third solvent, the first solvent is included in an amount of 100 to 1600 parts by weight based on 100 parts by weight of the second solvent, and the third solvent is included in an amount of 50 to 900 parts by weight based on 100 parts by weight of the second solvent.

[0158] For example, when the mixed solvent consists of a first solvent, a second solvent, and a third solvent, the sum of the amounts of the first solvent and the second solvent can be greater than the amount of the third solvent, and the sum of the amounts of the first solvent and the third solvent can be greater than the amount of the second solvent.

[0159] For example, when the mixed solvent consists of a first solvent, a second solvent, and a third solvent, the sum of the amounts of the second solvent and the third solvent can be greater than the amount of the first solvent.

[0160] For example, when the mixed solvent consists of a first solvent, a second solvent, and a third solvent, the sum of the amounts of the second solvent and the third solvent may be less than the amount of the first solvent.

[0161] For example, the mixed solvent may also contain a compound represented by chemical formula 4.

[0162] [Chemical Formula 4]

[0163]

[0164] In chemical formula 4,

[0165] R14 to R16 are each independently a substituted or unsubstituted C1 to C20 alkyl group.

[0166] For example, in Formula 4, R3 to R5 may each be independently C1 to C20 alkyl groups substituted with C2 to C10 alkenyl groups (e.g., vinyl groups) or unsubstituted with C2 to C10 alkenyl groups.

[0167] For example, a compound represented by chemical formula 4 may include at least one compound selected from either chemical formula 4-1 or chemical formula 4-2, but is not necessarily limited to this.

[0168] [Chemical Formula 4-1]

[0169]

[0170] [Chemical Formula 4-2]

[0171]

[0172] Meanwhile, compounds represented by chemical formula 1 can be represented by any of chemical formulas 1-1 to 1-6, but are not necessarily limited to these.

[0173] [Chemical Formula 1-1]

[0174]

[0175] [Chemical Formula 1-2]

[0176]

[0177] [Chemical Formulas 1-3]

[0178]

[0179] [Chemical Formulas 1-4]

[0180]

[0181] [Chemical Formulas 1-5]

[0182]

[0183] [Chemical Formulas 1-6]

[0184]

[0185] The solvent is contained in an amount of 20% to 99.99% by weight (e.g., 20% to 99.7% by weight, 20% to 95% by weight, 30% to 90% by weight) based on the total amount of the ink composition.

[0186] polymerizable monomers

[0187] The ink composition according to the embodiments may further include a polymerizable compound as needed. The polymerizable compound can be used by mixing monomers or oligomers commonly used in conventional curable compositions.

[0188] For example, a polymerizable compound can be a polymerizable monomer having a carbon-carbon double bond at the end.

[0189] For example, a polymerizable compound may be a polymerizable monomer having at least one of a functional group represented by chemical formula A-1 or a functional group represented by chemical formula A-2 at the end.

[0190] [Chemical Formula A-1]

[0191]

[0192] [Chemical Formula A-2]

[0193]

[0194] In chemical formulas A-1 and A-2,

[0195] La is a substituted or unsubstituted C1 to C20 alkyl group, and

[0196] Ra is a hydrogen atom or a substituted or unsubstituted C1 to C20 alkyl group.

[0197] The polymerizable compound can form a cross-linked structure with the surface-modifying compound through a functional group including at least one carbon-carbon double bond, specifically a functional group represented by chemical formula A-1 or a functional group represented by chemical formula A-2. The product with the cross-linked structure can further improve the dispersion stability of the semiconductor nanorods by doubling a type of steric hindrance effect.

[0198] For example, examples of polymerizable compounds that include at least one functional group represented by the chemical formula A-1 at the end may include, but are not limited to, divinylbenzene, triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, triallyl phosphate, triallyl phosphite, triallyl triazine, diallyl phthalate, or combinations thereof.

[0199] For example, polymerizable compounds comprising at least one functional group represented by the chemical formula A-2 at the end may include 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, phenolic epoxy acrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, polyfunctional epoxy (meth)acrylate, polyfunctional aminocarbamate (meth)acrylate, and KAYARAD manufactured by Japan Chemical Co., Ltd. DPCA-20, KAYARAD DPCA-30, KAYARAD DPCA-60, KAYARAD DPCA-120, KAYARAD DPEA-12 or combinations thereof, but not necessarily limited to these.

[0200] To impart better developability, polymerizable compounds can be treated with acid anhydrides.

[0201] Polymerization initiator

[0202] The curable composition according to the embodiments may further include, as needed, a polymerization initiator, such as a photopolymerization initiator, a thermal polymerization initiator, or a combination thereof.

[0203] Photopolymerization initiators can be initiators commonly used in curable components, such as acetophenone-based compounds, benzophenone-based compounds, thioxanthone-based compounds, benzoin-based compounds, triazine-based compounds, oxime-based compounds, and amino ketone-based compounds, but are not necessarily limited to these.

[0204] Examples of acetophenone compounds include 2,2'-diethoxyacetophenone, 2,2'-dibutoxyacetophenone, 2-hydroxy-2-methylacetophenone, p-tert-butyltrichloroacetophenone, p-tert-butyldichloroacetophenone, 4-chloroacetophenone, 2,2'-dichloro-4-phenoxyacetophenone, 2-methyl-1-(4-(methylthio)phenyl)-2-morpholinylprop-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-but-1-one, and the like.

[0205] Examples of benzophenone compounds may include benzophenone, benzoyl benzoate, benzoyl 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.

[0206] Examples of thioxanthone compounds include thioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 2-chlorothioxanthone, and the like.

[0207] Examples of benzoin compounds include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, and the like.

[0208] Examples of triazine compounds include 2,4,6-trichloro-s-triazine, 2-phenyl-4,6-bis(trichloromethyl)-s-triazine, 2-(3',4'-dimethoxystyryl)-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, 2-biphenyl-4,6-bis(trichloromethyl)-s-triazine, bis(trichloromethyl)-6-styryl-s-triazine, 2-(naphthyl-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxynaphthol-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2-4-bis(trichloromethyl)-6-piperyl-s-triazine, 2-4-bis(trichloromethyl)-6-(4-methoxystyryl)-s-triazine and the like.

[0209] Examples of oxime compounds may include O-acyloxime compounds, 2-(O-benzoyloxime)-1-[4-(phenylthio)phenyl]-1,2-octanedione, 1-(O-acetyloxime)-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]acetone, O-ethoxycarbonyl-α-oxyamino-1-phenylprop-1-one, and the like. Specific examples of O-acyl oxime compounds may include 1,2-octanedione, 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl)-but-1-one, 1-(4-phenylthiophenyl)-but-1,2-dione-2-oxime-O-benzoate, 1-(4-phenylthiophenyl)-oct-1,2-dione-2-oxime-O-benzoate, 1-(4-phenylthiophenyl)-oct-1-one-oxime-O-acetate, 1-(4-phenylthiophenyl)-but-1-one-oxime-O-acetate, and the like.

[0210] Examples of amino ketone compounds may include 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1.

[0211] In addition to the compounds mentioned above, the photopolymerization initiator may also include carbazole compounds, diketone compounds, sulfonium borate compounds, diazo compounds, imidazole compounds, biimidazole compounds, and similar compounds.

[0212] Photopolymerization initiators can be used with photosensitizers that can induce a chemical reaction by absorbing light, become excited, and subsequently transfer their energy.

[0213] Examples of photosensitizers include tetraethylene glycol bis-3-mercaptopropionate, pentaerythritol tetra-3-mercaptopropionate, dipentaerythritol tetra-3-mercaptopropionate, and similar compounds.

[0214] Examples of thermal polymerization initiators may be peroxides, specifically benzoyl peroxide, dibenzoyl peroxide, lauroyl peroxide, dilauryl peroxide, di-tert-butyl peroxide, cyclohexane peroxide, methyl ethyl ketone peroxide, hydroperoxides (e.g., tert-butyl hydroperoxide, cumene hydroperoxide), dicyclohexyl percarbonate, 2,2-azobis(isobutyronitrile), tributyl perbenzoate and the like, and may also be 2,2'-azobis-2-methylpropionitrile and the like, but are not necessarily limited thereto, and may include any initiator known in the art.

[0215] The polymerization initiator may be included in an amount of 1% to 5% by weight, for example, 2% to 4% by weight, based on the total solids content of the ink composition. When the polymerization initiator is included within this range, the ink composition can be fully cured during exposure or thermal curing, and thus achieves excellent reliability.

[0216] Other additives

[0217] The ink composition according to the embodiments may further include, as needed, a polymerization inhibitor, which includes hydroquinone compounds, catechol compounds, or combinations thereof. Because the ink composition according to the embodiments further includes hydroquinone compounds, catechol compounds, or combinations thereof, crosslinking at room temperature can be prevented during exposure after printing (coating) the ink composition.

[0218] For example, hydroquinone compounds, catechol compounds, or combinations thereof may include hydroquinone, methylhydroquinone, methoxyhydroquinone, tributylhydroquinone, 2,5-di-tert-butylhydroquinone, 2,5-bis(1,1-dimethylbutyl)hydroquinone, 2,5-bis(1,1,3,3-tetramethylbutyl)hydroquinone, catechol, tributylcatechol, 4-methoxyphenol, gallnutol, 2,6-di-tert-butyl-4-methylphenol, 2-naphthol, tris(N-hydroxy-N-nitrosophenylamino-O,O')aluminum, or combinations thereof, but are not necessarily limited thereto.

[0219] Hydroquinone compounds, catechol compounds, or combinations thereof can be used in dispersed form, and the polymerization inhibitor in the dispersed form may be included in an amount of 0.001% to 1% by weight, for example, 0.01% to 0.1% by weight, based on the total amount of the ink composition. When a stabilizer is included within the above range, the problem of aging at room temperature can be solved, and the reduction in sensitivity and surface peeling can be prevented.

[0220] In addition to polymerization inhibitors, the ink composition according to the embodiments may also include, as needed, malonic acid; 3-amino-1,2-propanediol; silane coupling agents; leveling agents; fluorinated surfactants; or combinations thereof.

[0221] For example, the ink composition may also contain a silane-based coupling agent having reactive substituents such as carboxyl, methacryloyl, isocyanate, epoxy, and similar groups to improve its tight contact properties with the substrate.

[0222] Examples of silane-based coupling agents may include trimethoxysilylbenzoic acid, γ-methpropenyloxypropyltrimethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, γ-isocyanate propyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, β-(epoxycyclohexyl)ethyltrimethoxysilane, and the like. These coupling agents may be used alone or in mixtures of two or more.

[0223] Based on 100 parts by weight of ink composition, a silane coupling agent may be included in an amount from 0.01 parts by weight to 10 parts by weight. When a silane coupling agent is included within the range described above, it can improve contact properties, storage properties, and similar properties.

[0224] Additionally, if necessary, the ink composition may also contain surfactants (e.g., fluorinated surfactants) to improve coating and prevent defects.

[0225] An example of a fluorinated surfactant is BM Chemie Inc. and Dainippon Ink Kagaku Kogyo Co., Ltd.'s MEGAFACE F Meijiafa F Meijiafa F and Meijiafa F FULORAD of Sumitomo 3M Co., Ltd. Florard Florard and Florard SURFLON from Asahi Glass Co., Ltd. Shafulong Shafulong Shafulong and Shafulong And Toray Silicone Co., Ltd. and And similar items; F-482, F-484, F-478, F-554 and similar items of DIC Co., Ltd.

[0226] Based on 100 parts by weight of ink composition, a fluorinated surfactant may be included in an amount from 0.001 parts by weight to 5 parts by weight. When a fluorinated surfactant is included within the above range, excellent wettability and coating uniformity on the glass substrate can be ensured, and no stains will be generated.

[0227] In addition, a certain amount of other additives (e.g., antioxidants and stabilizers) may be added to the ink composition without impairing its physical properties.

[0228] Adhesive resin

[0229] The ink composition may also include adhesive resin.

[0230] Adhesive resins may include acryloyl adhesive resins, caloyl adhesive resins, or combinations thereof.

[0231] Acryloyl-based adhesive resins and calorie-based adhesive resins may be any known resin commonly used in curable or photosensitive compositions, and the adhesive resins are not limited to a particular type.

[0232] The binder resin may be included in an amount of 1% to 30% by weight (e.g., 1% to 20% by weight) based on the total amount of the ink composition. When the binder resin is included within the above range, the curing shrinkage rate can be reduced.

[0233] Another embodiment provides a layer using the ink composition.

[0234] Another embodiment may provide an electrophoresis apparatus and / or a display device including the layer.

[0235] The invention is illustrated in more detail below with reference to examples. However, these examples should not be construed in any way as limiting the scope of the invention.

[0236] (Preparation of ink composition)

[0237] Examples 1 to 8 and Comparative Examples 1 to 2

[0238] GaN wafers (4 inches) patterned with nanorods were reacted in 40 mL of stearic acid (1.5 mmol / L mM) at room temperature for 24 hours. After the reaction, the GaN nanorods were immersed in 50 mL of acetone for 5 minutes to remove excess stearic acid, and the wafer surface was rinsed with 40 mL of acetone. The cleaned wafer was placed in a 27 kW ultrasonic bath with 35 mL of γ-butyrolactone (GBL) and then ultrasonicated for 5 minutes to separate the rods from the wafer surface. The separated rods were centrifuged in FALCON tubes, and 10 mL of GBL was added to further wash the rods on the surface of the bath. The supernatant was then discarded by centrifugation at 4000 rpm for 10 minutes, and the precipitate was redispersed in 40 mL of acetone and filtered through a 10-micron sieve. After additional centrifugation (4000 rpm, 10 min), the precipitate was dried in a drying oven (100 °C, 1 h), its weight was measured, and the corresponding nanorods were dispersed in each mixed solvent to 0.2 wt% to obtain each ink composition having the compositions shown in Table 1.

[0239] (The composition of each mixed solvent is the same as that in Table 2.)

[0240] (Table 1)

[0241] (Unit: % by weight)

[0242]

[0243] (Table 2)

[0244]

[0245] Assessment 1: Storage Stability

[0246] Storage stability was evaluated for pure mixed solvents according to Examples 1 to 8, and Comparative Examples 1 and 2, and the results are shown in Table 3. Specifically, each mixed solvent was allowed to stand at each temperature for 4 hours, and the morphological changes (phase separation of the solvent) were examined by visual inspection. In addition, 1 ml was taken from the top of each sample, and the change in composition ratio (change in solvent area %) of each sample relative to the initial solvent composition ratio was examined by gas chromatography analysis, and then evaluated according to the following criteria.

[0247] (1) Morphological changes

[0248] ○: No phase separation

[0249] X: Phase separation was observed.

[0250] (2) Changes in composition ratio

[0251] ○: The change in solvent composition ratio is less than 1%.

[0252] X: The change in solvent composition ratio is greater than or equal to 1%.

[0253] (Table 3)

[0254]

[0255] As shown in Table 3, Examples 1 to 8 exhibited superior storage stability at low temperatures compared to Comparative Examples 1 and 2.

[0256] Evaluation 2: Viscosity and Dielectrophoretic Properties

[0257] The initial viscosity of each nanorod-containing ink composition according to Examples 1 to 8 and Comparative Examples 1 and 2 at 25°C was measured using a viscometer (RV-2 rotor, 23 rpm, DV-II manufactured by Brookfield Engineering Laboratories, Inc., USA), and the results are shown in Table 4. In addition, the dielectric properties (deflection alignment and center alignment) of the ink compositions were measured using a Turbiscan analyzer, and the results are shown in Table 4.

[0258] Specifically, the dielectrophoretic properties were measured using the following method.

[0259] First, 500 μL of each ink composition was applied to a thin-film gold basic interdigitated linear electrode (ED-cIDE4-Au, Micrux Technologies), and then an electric field (25 kHz, ±30 V) was applied, followed by a 1-minute wait. Subsequently, after drying the solvent using a hot plate, the number of aligned and unaligned particles in the center between the electrodes was counted using a microscope to evaluate the dielectrophoretic properties.

[0260] (Table 4)

[0261]

[0262] As shown in Table 4, Examples 1 to 3, which contain a two-component solvent, exhibit superior dielectric properties compared to Comparative Example 1, which contains a two-component solvent. Furthermore, Examples 4 to 8, which contain a three-component solvent, exhibit superior dielectric properties and maintain high viscosity at 25°C compared to Comparative Example 2, which contains a three-component solvent. Therefore, the ink compositions according to the embodiments significantly improve the dispersion stability of semiconductor nanorods while exhibiting excellent dielectric properties, thus proving their suitability for large-area coating and panel production.

[0263] Although the invention has been described in conjunction with exemplary embodiments currently considered feasible, it should be understood that the invention is not limited to the disclosed embodiments, but rather is intended to cover various modifications and equivalent configurations included within the spirit and scope of the appended claims. Therefore, the above embodiments should be understood as exemplary and not as limiting the invention in any way.

Claims

1. An ink composition comprising (A) A semiconductor nanorod, wherein the semiconductor nanorod comprises a GaN-based compound, an InGaN-based compound, or a combination thereof; and (B) A mixed solvent comprising a first solvent and a second solvent, wherein the first solvent comprises a compound represented by chemical formula 1 and the second solvent comprises a compound represented by chemical formula 2. The ink composition mentioned above is an ink composition used in electrophoresis apparatus: [Chemical Formula 1] in, In chemical formula 1, R 1 To R 3 Each is independently a hydrogen atom or a C1 to C10 alkyl group. R 4 It is a hydrogen atom or *-C(=O)R 5 , where R 5 It is a C1 to C10 alkyl group and * indicates a connection point. L 1 and L 2 Each is independently a substituted or unsubstituted C1 to C20 alkyl or a substituted or unsubstituted C6 to C20 aryl, and L 3 It can be *-O-*, *-S-*, or *-NH-*, where * is a connection point. [Chemical Formula 2] In chemical formula 2, R 6 and R 7 Each is independently a hydrogen atom, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, or a substituted or unsubstituted C6 to C20 aryl group, and R 8 and R 9 Each is independently a hydrogen atom or *-(C=O)R 10 , where R 10 It is a substituted or unsubstituted C1 to C20 alkyl, a substituted or unsubstituted C3 to C20 cycloalkyl, or a substituted or unsubstituted C6 to C20 aryl, and * is the connecting point.

2. The ink composition according to claim 1, wherein chemical formula 2 is represented by chemical formula 2A: [Chemical Formula 2A] in, In chemical formula 2A, R 6 and R 7 Each is independently a hydrogen atom, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, or a substituted or unsubstituted C6 to C20 aryl group, and R 8 and R 9 Each is independently a hydrogen atom or *-(C=O)R 10 , where R 10 It is a substituted or unsubstituted C1 to C20 alkyl, a substituted or unsubstituted C3 to C20 cycloalkyl, or a substituted or unsubstituted C6 to C20 aryl, and * is the connecting point.

3. The ink composition according to claim 1, wherein R 8 and R 9 Each is an independent hydrogen atom.

4. The ink composition according to claim 1, wherein R 6 and R 7 Each is an independent hydrogen atom.

5. The ink composition according to claim 1, wherein the compound represented by chemical formula 2 includes compounds represented by any one of chemical formulas 2-1 to 2-4: [Chemical Formula 2-1] [Chemical Formula 2-2] [Chemical Formula 2-3] [Chemical Formula 2-4] 6. The ink composition according to claim 1, wherein the first solvent and the second solvent are mixed in a weight ratio of 1:1 to 1:

3.

7. The ink composition according to claim 1, wherein the mixed solvent further comprises a third solvent comprising a compound represented by chemical formula 3: [Chemical Formula 3] in, In chemical formula 3, R 11 To R 13 Each is independently a substituted or unsubstituted C1 to C20 alkoxy group.

8. The ink composition according to claim 7, wherein in chemical formula 3, R 11 To R 13 Each is independently a C1 to C20 alkoxy group with or without C2 to C10 alkenyl substitution.

9. The ink composition according to claim 7, wherein The first solvent is contained in an amount ranging from 100 parts by weight to 1600 parts by weight, based on 100 parts by weight of the second solvent. The third solvent is contained in an amount of 50 to 900 parts by weight, based on 100 parts by weight of the second solvent.

10. The ink composition according to claim 7, wherein The mixed solvent is composed of the first solvent, the second solvent, and the third solvent. The sum of the amounts of the first solvent and the second solvent is greater than the amount of the third solvent, and The sum of the amount of the first solvent and the amount of the third solvent is greater than the amount of the second solvent.

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

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

13. The ink composition according to claim 1, wherein the semiconductor nanorod has a surface coated with a metal oxide.

14. The ink composition of claim 13, wherein the metal oxide comprises aluminum oxide, silicon dioxide, or a combination thereof.

15. The ink composition of claim 1, wherein the semiconductor nanorod is contained in an amount of 0.01% to 10% by weight, based on the total amount of the ink composition.

16. 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 fluorinated surfactant; or a combination thereof.

17. A layer manufactured using an ink composition as described in any one of claims 1 to 16.

18. An electrophoresis apparatus comprising the layer as described in claim 17.

19. A display device comprising the layer as claimed in claim 17.

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