Method of manufacturing a patterned flexible electrode

Abstract

This invention relates to a method for manufacturing patterned flexible electrodes. More specifically, the manufacturing method of this invention includes: a nanowire forming step, wherein a first dispersion containing metal nanowires is coated on a first sheet unwound from a wound state to form a nanowire mesh; a fiber forming step, wherein a second dispersion containing metal nanoparticles is electrospun onto the nanowire mesh to form a fiber-nanowire mesh in which metallic fibers composed of aggregated metal nanoparticles are mixed in; and a sintering step, wherein the fiber-nanowire mesh is photon sintered to form a conductive mesh, and a patterning step is performed, wherein the fiber-nanowire mesh is patterned before the sintering step, or the conductive mesh is patterned after the sintering step.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing patterned flexible electrodes, and more specifically, to a method for manufacturing patterned flexible electrodes that also have excellent electrical and optical properties with a fine electrode width. Background Technology

[0002] Traditional transparent electrodes based on transparent conductive oxides, such as ITO, are difficult to scale up to a large area and require expensive and demanding processes such as vacuum evaporation. Not only do their electrical properties decrease significantly when miniaturized, but they also lack flexibility, making them unsuitable for use in flexible micro-devices.

[0003] To address the problems of existing transparent electrodes, ongoing research is underway to develop flexible transparent electrodes using nanomaterials such as carbon nanotubes, graphene, and metal nanowires.

[0004] However, even when using nanomaterials, there are problems such as increased electrode resistance due to contact resistance between nanomaterials as the linewidth of the electrode becomes smaller. Furthermore, when a large current is passed through, there is a problem of damage to the nanomaterials due to electromigration and other factors.

[0005] To address the problems associated with this type of nanomaterial, a hybrid structure technology has been proposed, which combines a first nanostructure with a first diameter and a second nanostructure with a second diameter, wherein the second diameter is smaller than the first diameter (Korean Patent No. 1863818). Regarding the proposed composite electrode technology, it exhibits excellent electrical properties even when the electrode has a very fine linewidth. However, it suffers from reduced transparency when improving electrical properties, and its electrical properties deteriorate rapidly due to repeated bending, thus hindering its application in practical flexible or rollable devices.

[0006] [Existing technical documents]

[0007] [Patent Literature]

[0008] Korean Patent No. 1863818 Summary of the Invention

[0009] Technical problems to be solved

[0010] The present invention aims to provide a patterned flexible transparent electrode with excellent electrical, optical and mechanical properties through a commercially viable, simple and rapid continuous process, and a method thereof for manufacturing the same.

[0011] Technical solution

[0012] A method for manufacturing patterned flexible electrodes includes: a nanowire forming step, in which a first dispersion containing metal nanowires is coated on a first sheet unwound from a wound state to form a nanowire mesh; a fiber forming step, in which a second dispersion containing metal nanoparticles is electrospun onto the nanowire mesh to form a fiber-nanowire mesh in which metallic fibers composed of aggregated metal nanoparticles are mixed into the nanowire mesh; and a sintering step, in which the fiber-nanowire mesh is photon sintered to form a conductive mesh, and a patterning step is performed, wherein the fiber-nanowire mesh is patterned before the sintering step or the conductive mesh is patterned after the sintering step using a patterning roller.

[0013] In a manufacturing method according to one embodiment of the present invention, during the patterning step, a patterning roller forming protrusions rotates and contacts the first sheet and a second sheet, which is a transparent sheet unwound from a wound state, respectively. Through the contact between the first sheet and the patterning roller, the fiber-nanowire mesh or the conductive mesh is patterned in the shape of the protrusions and transferred to the patterning roller. Through the contact between the patterning roller and the second sheet, the patterned mesh located on the patterning roller can be transferred to the second sheet.

[0014] In a manufacturing method according to one embodiment of the present invention, the protrusions of the patterned roller may be siloxane-based elastomers.

[0015] In a manufacturing method according to an embodiment of the present invention, pressure can be applied when the first sheet contacts the patterning roller and when the second sheet contacts the patterning roller, respectively, by means of a first pressure roller and a second pressure roller. The first pressure roller and the patterning roller are disposed opposite to each other, and the first sheet is located between the first pressure roller and the patterning roller. The second pressure roller and the patterning roller are disposed opposite to each other, and the second sheet is located between the second pressure roller and the patterning roller.

[0016] In a manufacturing method according to one embodiment of the present invention, at least the surface of the second sheet in contact with the patterning roller may be a surface treated with corona, plasma or ozone.

[0017] In a manufacturing method according to one embodiment of the present invention, drying may be performed immediately after the nanowire forming step or the fiber forming step, the drying being carried out by irradiation with light including ultraviolet light, application of hot air or dry air, or heating.

[0018] In a manufacturing method according to one embodiment of the present invention, during the fiber forming step, during electrospinning, a coaxial dual nozzle including an internal nozzle and an external nozzle surrounding the internal nozzle can be used to spin the second dispersion through the internal nozzle and the polymer solution through the external nozzle to form a composite fiber in which the metallic fiber is encapsulated in a polymer sheath.

[0019] In a manufacturing method according to one embodiment of the present invention, after electrospinning, a step of removing the polymer sheath from the composite fiber may be included.

[0020] In a manufacturing method according to one embodiment of the present invention, the metallic fiber can be transformed into a conductive fiber through the sintering step, and the fibers and nanowires of the fiber-nanowire mesh can be fused together, as well as the nanowires and nanowires together.

[0021] In a manufacturing method according to one embodiment of the present invention, in the nanowire forming step, the nanowire fill factor, which is a proportion of the area covered by the metal nanowires in the area of ​​the first sheet, can be 3-11%, the fiber fill factor, which is a proportion of the area covered by the metallic fibers, can be 3-10%, and the mesh fill factor, which is a proportion of the sum of the areas covered by the fiber-nanowire mesh, can be 9-13%.

[0022] In a manufacturing method according to one embodiment of the present invention, the photonic sintering can be carried out by irradiation with an intensity of 800-1600 J / cm. 2 It uses pulsed white light.

[0023] In a manufacturing method according to one embodiment of the present invention, the ratio of the diameter of the metallic fiber to the diameter of the metallic nanowire can be 10-1000.

[0024] In a manufacturing method according to one embodiment of the present invention, the metal nanoparticles of the metallic fiber and the metal nanowires may respectively comprise silver (Ag), gold (Au), aluminum (Al), copper (Cu), chromium (Cr), nickel (Ni), iron (Fe) or alloys thereof.

[0025] The present invention includes a patterned flexible electrode manufactured by the above-described manufacturing method.

[0026] The patterned flexible electrode of the present invention comprises: a transparent sheet; a patterned electrode located on the transparent sheet, and comprising a conductive mesh containing metal nanowires and metallic conductive fibers, wherein, based on the electrode region in the transparent sheet where the patterned electrode is located, the nanowire filling factor, as a proportion of the area covered by the metal nanowires, is 3-11%, the fiber filling factor, as a proportion of the area covered by the conductive fibers, is 3-10%, and the conductive mesh filling factor, as a proportion of the area covered by the conductive mesh, is 9-13%.

[0027] According to one embodiment of the present invention, the light transmittance of the patterned flexible electrode based on the electrode area can be more than 90%, and the sheet resistance based on a linear pattern with a line width of 1 mm can be less than 80 Ω / sq.

[0028] According to one embodiment of the present invention, for a patterned flexible electrode, when a bending test is performed 100,000 times with a bending radius of 3 mm based on a linear pattern with a line width of 1 mm, the increase rate of the thin film resistance can be less than 8%.

[0029] Beneficial effects

[0030] The manufacturing method of the present invention is based on a simple and rapid in-line continuous process without utilizing lithography or etching processes. Therefore, the manufacturing method has the advantage of being able to mass-produce patterned flexible electrodes with excellent optical, mechanical and electrical properties. Attached Figure Description

[0031] Figure 1 This is an example of a flowchart illustrating a patterning step using a patterning roller after a sintering step according to an embodiment of the present invention.

[0032] Figure 2 This is an example of a flowchart illustrating a patterning step using a patterning roller prior to a sintering step according to another embodiment of the invention.

[0033] Figure 3 It is a scanning electron microscope image of a conductive grid manufactured according to one embodiment of the present invention.

[0034] Figure 4 These are scanning electron microscope images of the mesh portions between nanowires in a conductive mesh manufactured according to an embodiment of the present invention.

[0035] Figure 5This is a graph showing the sheet resistance measured according to the number of bends after performing 100,000 bending tests on a transparent electrode with a radius of curvature of 3 mm, wherein the transparent electrode is manufactured by photonic sintering an unpatterned grid layer.

[0036] Figure 6 This is a graph showing the sheet resistance measured according to the number of bends after performing 100,000 bending tests on a transparent electrode with a radius of curvature of 3 mm. The transparent electrode is manufactured by photonic sintering a grid of linear electrodes with a width of 1 mm. Detailed Implementation

[0037] Hereinafter, with reference to the accompanying drawings, the patterned flexible electrode and its manufacturing method of the present invention will be described in detail.

[0038] The accompanying drawings described below are provided as examples to fully convey the spirit of the invention to those skilled in the art. Therefore, the invention is not limited to the drawings and can be implemented in other embodiments, and the drawings may be enlarged to illustrate the spirit of the invention. Here, unless otherwise defined, technical and scientific terms used have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In the following description and drawings, descriptions of well-known functions and structures that might unnecessarily obscure the spirit of the invention are omitted.

[0039] Furthermore, unless otherwise specified, the singular form used in the specification and claims also includes the plural form in the text.

[0040] In this specification and claims, the terms "first," "second," etc., are not limiting in meaning, but are used to distinguish one constituent element from other constituent elements.

[0041] In this specification and claims, terms such as include, comprise, or have refer to the presence of a feature or constituent element described in the specification, and unless otherwise specified, do not preclude the possibility of adding more than one other feature or constituent element.

[0042] In this specification and claims, when describing a membrane (layer), region, constituent element, etc., as being above or on top of other parts, it includes not only the case where it is in contact with other parts and directly above them, but also the case where other membranes (layers), other regions, other constituent elements, etc. are disposed in between.

[0043] The method for manufacturing patterned flexible electrodes according to the present invention includes: a nanowire forming step, wherein a first dispersion containing metal nanowires is coated on a first sheet unwound from a wound state to form a nanowire mesh; a fiber forming step, wherein a second dispersion containing metal nanoparticles is electrospun onto the nanowire mesh to form a fiber-nanowire mesh in which metallic fibers composed of aggregated metal nanoparticles are mixed in; and a sintering step, wherein the fiber-nanowire mesh is photonically sintered to form a conductive mesh, and a patterning step is performed, wherein the fiber-nanowire mesh is patterned before the sintering step or the conductive mesh is patterned after the sintering step using a patterning roller.

[0044] As described above, in the method for manufacturing patterned flexible electrodes according to the present invention, a metal nanowire mesh is first formed on a first thin sheet. Then, a second dispersion is electrospun onto the metal nanowire mesh, incorporating a mesh of metallic fibers to form a fiber-nanowire mesh. The manufactured fiber-nanowire mesh is then photonically sintered to transform it into a conductive mesh. This method allows for the fabrication of flexible electrodes with very high transparency and significantly superior electrical properties, as well as flexible electrodes exhibiting excellent flexibility that shows almost no deterioration in electrical properties even under fine electrode spacing and repeated deformation. Here, the mesh can refer to a structure where nanowires or fibers are randomly contacted and provide a continuous path between any two locations.

[0045] Furthermore, as described above, in the method for manufacturing patterned flexible electrodes of the present invention, before or after photonic sintering, a patterning roller is used to pattern the mesh layer (fiber-nanowire mesh layer or conductive mesh layer) formed on the first sheet into a designed pattern. Therefore, in the absence of lithography as a precise multi-step process or etching process that generates toxic waste, the fiber-nanowire mesh layer or conductive mesh layer can be patterned by using a physical method with a patterning roller.

[0046] By utilizing physical patterning with patterning rollers and sintering with light (photonic sintering), the process for manufacturing patterned flexible electrodes, including nanowire formation, fiber formation, electrode patterning, and sintering, can be realized as a continuous sequential process. Hereinafter, the layered fiber-nanowire mesh or conductive mesh located on the first sheet is referred to as the "mesh layer" or "mesh," and the fiber-nanowire mesh or conductive mesh patterned by the patterning roller is referred to as the "patterned mesh."

[0047] In one specific embodiment, the first dispersion may contain metal nanowires and a first dispersion medium. The metal nanowires may be silver (Ag), gold (Au), aluminum (Al), copper (Cu), chromium (Cr), nickel (Ni), iron (Fe), or alloys thereof, but are not limited thereto. In the case of micropatterning with micro-pitch (width) on the order of tens of micrometers, the average diameter of the metal nanowires may also be on the order of 5-100 nm, and the aspect ratio may be 100-10000, so that a stable mesh can be formed by the nanowires, but is not necessarily limited thereto.

[0048] The first dispersion medium can be any solvent that facilitates the dispersion of metal nanowires and can be volatilized and removed at low temperatures. As a specific example, the first dispersion medium may include ethyl butoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethylene glycol butyl ether, cyclohexanone, cyclohexanol, 2-ethoxyethyl acetate, ethylene glycol diacetate, terpineol, isobutanol, water, or mixtures thereof, but the present invention is not limited to the type of first dispersion medium.

[0049] Based on 100 parts by weight of the first dispersion medium, the first dispersion may contain 0.01-70 parts by weight of metal nanowires, but the present invention is not limited to the content of metal nanowires in the first dispersion.

[0050] If necessary, in addition to the metal nanowires and the first dispersion medium, the first dispersion may also include additives commonly used in nanowire dispersions in the field of nanowire-based transparent electrodes, such as dispersants, corrosion inhibitors, binders, etc., for improving the dispersibility of nanowires.

[0051] The coating of the first dispersion can be performed using any method employed in semiconductor or display manufacturing to create films or patterns by coating a liquid or dispersed phase and drying it. As an example, the coating of the first dispersion can include various methods such as coating, spraying, and printing. Specific examples include spin coating, screen printing, inkjet printing, rod coating, gravure coating, doctor blade coating, roller coating, slot extrusion coating, electrospinning, and jet spinning, but are not limited to these.

[0052] In the nanowire formation step, drying can be performed after coating the first dispersion, if necessary. Drying can be carried out by natural drying, irradiation with light including ultraviolet light, hot air drying, methods utilizing the flow of dry air, heating using a heat source, etc. However, electrospinning in the fiber formation step can also be performed without a separate drying step.

[0053] The fiber formation step involves electrospinning to incorporate metallic fibers into a nanowire mesh, forming a fiber-nanowire mesh. Here, unless otherwise specified, metallic fibers refer to metal nanoparticles aggregated into a fibrous form, possessing a high electrical resistance to the extent that they cannot be used as electrodes. As described below, the aggregated metal nanoparticles are fused together through photonic sintering in the sintering step, thereby transforming the metallic fibers into conductive fibers with electrical conductivity. Therefore, it is necessary to clearly distinguish between metallic fibers and conductive fibers.

[0054] The fiber forming step may include the following steps: using a coaxial dual nozzle including an internal nozzle and an external nozzle surrounding the internal nozzle, spinning a second dispersion containing metal nanoparticles through the internal nozzle, and spinning a polymer solution through the external nozzle, to form a composite fiber in which metallic fibers are encapsulated in a polymer sheath.

[0055] Polymers are spun from external nozzles, encapsulating metal nanoparticles spun from internal nozzles. The metal nanoparticles are not sprayed over a wide area and can form and maintain the fiber shape.

[0056] The metal nanoparticles and metal nanowires in the second dispersion can be independently silver (Ag), gold (Au), aluminum (Al), copper (Cu), chromium (Cr), nickel (Ni), iron (Fe), or alloys thereof, but are not limited thereto. However, the metal nanoparticles are preferably the same metal as the metal nanowires, so that the metal nanoparticles fuse together during photonic sintering in the sintering step, and that the contact sites between the conductive fibers (or the metallic fibers in the process of converting to conductive fibers) and the metal nanowires, as well as between the metal nanowires, can be uniformly and stably fused together easily.

[0057] The metal nanoparticles only need to be of a size that allows them to be easily spun through an internal nozzle. As an example, the diameter of the metal nanoparticles can be in the range of 5-200 nm. However, preferably, the diameter of the metal nanoparticles is in the range of 5-100 nm, specifically 5-60 nm, and more specifically 20-60 nm, so that the metal nanoparticles can provide a high sintering driving force during photonic sintering in the sintering step.

[0058] The content of metal nanoparticles in the second dispersion can be 60-85% by weight, but is not limited to this. The dispersion medium of the second dispersion can be alkanes, aromatics, ethers, haloalkanes, esters, aldehydes, ketones, amines, alcohols, amides, water, or mixtures thereof. As an example, the dispersion medium of the second dispersion can be methanol, acetone, tetrahydrofuran, toluene, diethyl ether, dimethylformamide, chloroform, α-terpineol, etc., but is not limited to this.

[0059] The polymer in the polymer solution can be polyvinylpyrrolidone, polyvinyl alcohol, polymethyl methacrylate, polydimethylsiloxane, polyurethane, polyether urethane, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, polymethyl methacrylate, polyvinyl acetate, polyacrylonitrile, polyfurfuryl alcohol, polystyrene, polyethylene oxide, polypropylene oxide, polycarbonate, polyvinyl chloride, polycaprolactone, polyvinyl fluoride, polyamide, or copolymers thereof, etc. However, any polymer can be used as long as it is a substance that can be easily electrospun. The solvent in the polymer solution can be any liquid phase substance that can dissolve the polymer and is easily volatilized and removed, such as alkanes, aromatics, ethers, haloalkanes, esters, aldehydes, ketones, amines, alcohols, amides, water, or mixtures thereof. The concentration of the polymer in the polymer solution only needs to be at the level of 20-80% by weight.

[0060] The diameter of the metallic fiber can be controlled by the diameter of the inner nozzle of the coaxial dual nozzle, and the thickness of the polymer sheath can be controlled by the spacing between the inner and outer nozzles.

[0061] Compared to nanowires, metallic fibers, which are transformed into conductive fibers through a sintering process, have lower resistance and can form the main current flow path. When the main current flow path through the fiber is interrupted due to micropatterning, the relatively fine nanowires can act as a connector between fibers.

[0062] Therefore, the diameter of the metallic fiber (internal nozzle diameter) can be 10. 2 From nm to 10 1 The level is on the μm scale, specifically 10 0 μm scale to 10 1 At the μm level, the metallic fibers can provide the main current movement path with a resistance lower than that of nanowires. As an example, the diameter of the metallic fibers can be from 500 nm to 10 μm or from 1 μm to 5 μm. Furthermore, the ratio of the diameter of the metallic fiber to the diameter of the metallic nanowire can be 10-1000, specifically 50-1000, but is not necessarily limited to this. In this case, the metallic fibers (or composite fibers) are formed by electrospinning, so the length of the metallic fibers (or composite fibers) is substantially unlimited. As an example, the length of the metallic fibers (or composite fibers) can reach several centimeters to tens of centimeters; as an extreme example, the metallic fibers (or composite fibers) introduced into the nanowire mesh can be randomly bent and wound single fibers.

[0063] The thickness of the polymer sheath (the spacing between the inner and outer nozzles) can be sufficient to stably constrain the metal nanoparticles spun from the inner nozzle into a fibrous morphology. As an example, the thickness of the polymer sheath can be in the range of 0.1-1D, based on the diameter (D) of the metallic fiber, but is not limited to this.

[0064] In one specific implementation, during electrospinning for forming metallic fibers, the nozzle discharge rate can be at the level of 0.1-1.0 ml / h, and the voltage can be at the level of 5-10 kV, but is not limited thereto.

[0065] As described above, composite fibers can be introduced into a nanowire mesh through electrospinning. The composite fibers are core-sheath structures with metallic fibers as the core and polymers as the sheath.

[0066] After electrospinning in the fiber forming step and before sintering in the sintering step, or during the patterning step before the sintering step, a sheath removal step can also be performed after electrospinning and before patterning in the patterning step to remove the polymer sheath from the composite fiber. The polymer sheath can be removed by wet removal using organic solvents, dry removal using reactive ion etching (RIE), thermal decomposition removal by heat treatment in air at a level of 150-200°C, or a combination thereof. However, in sequential continuous processes, removing the polymer sheath by spraying or immersing (soaking) in organic solvents is advantageous. Therefore, a method for manufacturing a patterned flexible electrode according to an advantageous example may include: a nanowire forming step, coating a first dispersion containing metal nanowires onto a first sheet unwound from a wound state to form a nanowire mesh; electrospinning using a coaxial dual nozzle, spinning a second dispersion containing metal nanoparticles through an internal nozzle and spinning a polymer solution through an external nozzle to introduce composite fibers into the nanowire mesh, wherein metallic fibers formed by the aggregation of metal nanoparticles in the composite fibers are encapsulated in a polymer sheath; a fiber forming step, removing the polymer sheath of the composite fibers using an organic solvent to form a fiber-nanowire mesh incorporating metallic fibers; and a sintering step, photonic sintering the fiber-nanowire mesh to form a conductive mesh, and may include a patterning step, wherein the fiber-nanowire mesh is patterned before the sintering step using a patterning roller, or the conductive mesh is patterned after the sintering step, wherein the removal of the polymer sheath using an organic solvent can be performed by spraying an organic solvent or immersing (soaking) in an organic solvent.

[0067] When forming a nanowire mesh in the nanowire formation step and forming metallic fibers in the fiber formation step, in the first sheet, the nanowire fill factor (area covered by nanowires / area of ​​the first sheet), which is the proportion of the area covered by the metallic nanowires, can be 3-11%, and the fiber fill factor (area covered by fibers / area of ​​the first sheet), which is the proportion of the area covered by the metallic fibers, can be 3-10%. Furthermore, while satisfying the nanowire fill factor and the fiber fill factor, the mesh fill factor (area covered by the fiber-nanowire mesh / area of ​​the first sheet), which is the proportion of the sum of the areas covered by the metallic nanowires and the areas covered by the metallic fibers, can be 9-13%, specifically 11-13%.

[0068] That is, during the coating process in the nanowire formation step, a first dispersion can be coated to achieve a nanowire filling coefficient of 3-11%, and during the electrospinning process in the fiber formation step, a second dispersion can be electrospinned to achieve a fiber filling coefficient of 3-10%. Furthermore, the coating process in the nanowire formation step and the electrospinning process in the fiber formation step can be combined to achieve a fiber-nanowire mesh filling coefficient of 9-13%.

[0069] By ensuring that the nanowire filling coefficient and fiber filling coefficient meet the above-mentioned ranges, and preferably by ensuring that the nanowire filling coefficient, fiber filling coefficient, and fiber-nanowire mesh filling coefficient meet the above-mentioned ranges, the manufactured electrode can have excellent electrical conductivity and high transparency (transmittance).

[0070] Specifically, the nanowire filling factor can be 3-5%, the fiber filling factor can be 8-10%, and the mesh filling factor can be 11-13%. Alternatively, the nanowire filling factor can be 8-11%, the fiber filling factor can be 3-5%, and the mesh filling factor can be 11-13%. When the filling factors described above are met, the electrode manufactured by photonic sintering of the mesh layer can have a transmittance of over 90%, specifically over 91%, and more specifically over 92%, exhibiting excellent optical properties as described above while also possessing excellent electrical properties with a sheet resistance of less than 1.9 Ω / sq, specifically less than 1.8 Ω / sq, and more specifically less than 1.7 Ω / sq. In this case, the transmittance can be measured according to ASTM D 1003, specifically at a wavelength of 550 nm. Furthermore, experimentally, the sheet resistance can be measured using a four-point probe. Furthermore, the sheet resistance can be the average of sheet resistance values ​​measured in 5 or more arbitrary regions, specifically, the average of sheet resistance values ​​measured in 5-50 arbitrary regions. Experimentally, the filling factor of the nanowires or fibers can be the value measured for samples where, similar to electrode manufacturing, a first dispersion is coated onto a first sheet to create a sample forming a nanowire mesh, and the measured value is the nanowire filling factor; or, similar to electrode manufacturing, a second dispersion is electrospun onto a first sheet (the first sheet without nanowire coating), and the polymer sheath is removed to create a sample forming a fiber mesh, and the measured value is the fiber filling factor. The mesh filling factor can also be the value measured for samples where, similar to electrode manufacturing, a first dispersion is coated onto a first sheet to form a nanowire mesh, and then a second dispersion is electrospun onto the nanowire mesh and the polymer sheath is removed to create a sample forming a fiber-nanowire mesh, and the measured value is the mesh filling factor. For measuring the various filling coefficients, images of the fine tissue can be obtained using a scanning electron microscope or similar instrument. The filling coefficient can then be calculated by determining the area of ​​fibers (fiber filling coefficient), the area of ​​nanowires (nanowire filling coefficient), or the area occupied by fibers and nanowires (mesh filling coefficient) within the total area of ​​the image. For ease of calculation, the observed image can be converted to black and white, and nanowires or fibers can be designated as black or white. The covered area can be calculated using the number of black or white pixels relative to the total number of pixels in the image. Furthermore, each filling coefficient can be the average of the filling coefficient values ​​measured in 5 to 50 arbitrary regions of each sample.

[0071] As described above, the fiber-nanowire mesh manufactured through the fiber forming step can be in a state with very high sintering driving force through metallic nanoparticles of metallic fibers.

[0072] A sintering step can be performed on the fiber-nanowire mesh before or after the patterning step.

[0073] Photonic sintering, through a sintering step, allows metal nanoparticles aggregated into fiber form to melt and bond together, and the metallic fibers can be transformed into conductive fibers. At the same time, fusion (bonding) can be achieved at the contact points between fibers and nanowires, as well as at the contact points between nanowires.

[0074] Photonic sintering can be achieved by irradiation intensity of 800-1600 J / cm. 2 Specifically, the strength is 1300-1600 J / cm. 2 The process involves using pulsed white light. The white light can have a bandwidth of 300-1000 nm, and the pulse width can be 500-2000 microseconds, specifically 1000-2000 microseconds. The number of pulses used during photon sintering can be 1-5, specifically 1-3, but is not limited to these values.

[0075] When sintering by heat treatment, the laminate, including the first sheet located beneath the fiber-nanowire mesh, needs to be heated as a whole, posing a risk of thermal damage to the first sheet. Furthermore, there is a limitation requiring the use of a first sheet with appropriate heat resistance. Additionally, sintering by heat treatment requires performing the heat treatment at the lowest possible temperature, necessitating long heat treatment sessions lasting several hours to achieve high electrical conductivity, making it difficult to use in industrial processes. Moreover, according to the present invention, since the nanowire mesh is formed first and then the metallic fibers are mixed into it, the nanowire mesh can only be heat-treated together with the metallic fibers. For fiber sintering, the nanowires are unnecessarily heated at high temperatures for extended periods, leading to nanowire breakage and a risk of thermal damage to the nanowire mesh.

[0076] On the other hand, photonic sintering can be completed in milliseconds or seconds, with no thermal damage to the first sheet. It is also an extremely simple and low-cost energy-saving process, thus offering superior commercial viability compared to heat treatment. Furthermore, according to the present invention, when a nanowire mesh is first formed and then metallic fibers are mixed into it before photonic sintering, the nanowires are pressed by the metallic fibers, thus effectively suppressing the reduction of contact points caused by the twisting of the nanowires during photonic sintering.

[0077] Unlike this invention, where the second dispersion is electrospun onto a substrate and sintered after removing the polymer sheath to form a conductive fiber mesh, followed by coating with metal nanowires, the metal nanowires are introduced into the conductive fiber mesh. However, because the metal nanoparticles are already sintered and have lost most of their sintering driving force, there is a limitation that the metal nanowires and conductive fibers are substantially difficult to fuse. In fact, to fuse the metal nanowires to the sintered conductive fibers, a higher thermal or optical energy is required compared to the energy needed for fusion at the contact points between the nanowires. Therefore, there is a risk that partial melting of the metal nanowires may lead to nanowire breakage and damage to the nanowire mesh.

[0078] Furthermore, unlike the present invention, when the second dispersion is electrospun onto a substrate and the polymer sheath is removed to form a network of metallic fibers, followed by coating with metal nanowires to introduce them into the metallic fiber network, and then sintering to transform the metallic fiber network into a conductive fiber network, the electrical / mechanical properties of the electrode are significantly reduced during photonic sintering. Therefore, there is a limitation that photonic sintering, which is advantageous for industrialization, cannot be utilized. In fact, when photonic sintering is performed after introducing metal nanowires into the metallic fiber network, there is a risk that the lower portion of the metallic fiber in the region where contact points between the metal nanowires accumulate may not be completely transformed into conductive fibers. When the electrode deforms, stress concentrates in this incompletely transformed region, leading to fiber breakage and potentially a significant reduction in electrical properties.

[0079] On the other hand, according to the present invention, a metal nanowire mesh is first formed on a first thin sheet, and metallic fibers are introduced into the nanowire mesh. Then, when the nanowire mesh with introduced metallic fibers (fiber-nanowire mesh) is sintered simultaneously, the entire metallic fiber is uniformly sintered through photon sintering and transformed into conductive fiber. At the same time, stable and uniform fusion can be achieved between the fiber and the nanowire, and between the nanowires.

[0080] Therefore, electrodes manufactured by photonic sintering of the mesh layer can also exhibit extremely excellent physical / electrical properties, with the thin-film resistance increase rate remaining below 5%, even when subjected to 100,000 bending tests with a bending radius of 3 mm.

[0081] As described above, a patterning step can be performed before or after the sintering step to physically pattern the mesh layer using a patterning roller.

[0082] Figure 1 This is an example of a flowchart illustrating a patterning step using a patterning roller after the sintering step according to an embodiment of the present invention. Figure 2This is an example of a flowchart illustrating a patterning step using a patterning roller prior to a sintering step according to another embodiment of the invention.

[0083] However, since the nanowires and fibers instantaneously heated by light irradiation during photonic sintering are both metals with excellent thermal conductivity, the transparent sheet region in contact with the conductive mesh is heated above its glass transition temperature (Tg), and the conductive mesh can be bonded to the transparent sheet. Therefore, regarding the excellent bonding with the transparent sheet, such as... Figure 2 As shown, preferably, a patterning step is performed after the fiber forming step, in which light is irradiated onto the patterned mesh and photonic sintering is performed. However, bonding between the mesh and the sheet during photonic sintering can be prevented by forming a release layer with a high Tg on the first sheet, so patterning using a patterning roller can also be performed after photonic sintering. The present invention does not exclude the case of patterning after photonic sintering.

[0084] like Figure 1 In the example shown, after performing the nanowire formation step (metal nanowire coating), the fiber formation step (metal nanofiber coating), and the sintering step (photonic sintering), a physical patterning step using a patterning roll can be performed. Alternatively, as... Figure 2 As shown in one example, after performing the nanowire formation step (coating metal nanowires) and the fiber formation step (coating metal nanofibers), a patterning step and a sintering step (photon sintering) using a physical method with a patterning roller can be performed.

[0085] In the patterning step, the patterning roller forming the protrusions rotates and interacts with the first sheet (1) respectively. st (sheet) and a second sheet (2) which is a transparent sheet unwound from the rolled-up state. nd In the first sheet contact with the patterning roller, the grid layer is patterned in the shape of the protrusion of the patterning roller and transferred to the patterning roller. In the second sheet contact with the patterning roller, the patterned grid on the patterning roller can be transferred to the second sheet.

[0086] The patterning roller may include protrusions having shapes and sizes corresponding to the designed electrode patterns. Therefore, the shape and size of the protrusions can be appropriately varied depending on the application of the flexible electrodes. As an example, considering applications such as touch panels or fingerprint recognition sensors, linear protrusions spaced apart from each other in the direction of roller rotation or the width direction of the roller can be formed on the patterning roller. Figure 1One example is the formation of linear protrusions spaced apart from each other along the width direction of the roller, which corresponds to an instance where the width of the roller has a length corresponding to the width of the first or second sheet. In this case, the width of the linear protrusions can be 10... 1 μm scale to 10 4 The invention is at the μm level, but it is not limited to the specific shape or size of the protrusions on the patterned roller.

[0087] The grid layer on the first sheet contacts the protrusion of the patterning roller. The portion of the grid layer in contact with the protrusion does not fall off and adheres to the protrusion, thereby achieving physical patterning. The protrusion then contacts the second sheet, and the portion of the grid layer attached to the protrusion is transferred to the second sheet, thus forming a patterned grid on the second sheet.

[0088] like Figure 1 and Figure 2 In one example shown, when patterning is performed using a patterning roller, the first pressure roller (1) is used. st When the first sheet comes into contact with the patterning roller, pressure can be applied (first pressure). The first pressure roller and the patterning roller are arranged opposite to each other. The first sheet (1 st The sheet is located between the first pressure roller and the patterning roller, and passes through the second pressure roller (2). nd When the second sheet comes into contact with the patterning roller, pressure can be applied (second pressure). The second pressure roller and the patterning roller are arranged opposite to each other. The second sheet (2 nd A sheet is positioned between the second pressure roller and the patterning roller. This pressure facilitates the physical patterning of the mesh layer through the protrusions and makes the patterned mesh easy to transfer. The first pressure of the first pressure roller can be appropriately adjusted to the extent that the protrusions compress the mesh layer and can easily cut the mesh layer at the edge region of the protrusions. As a specific embodiment, the first pressure can be at the level of 50-1000 kPa, specifically at the level of 100-1000 kPa, but is not necessarily limited to this. Furthermore, the second pressure of the second pressure roller can be appropriately adjusted to the extent that the patterned mesh located on the protrusions of the patterning roller can be stably transferred to the second sheet. As a specific embodiment, the second pressure can be at the level of 50-1000 kPa, specifically at the level of 50-700 kPa, but is not limited to this.

[0089] At least the protrusions of the patterning roller can be made of siloxane elastomers. Siloxane elastomers have high elasticity and are not easily damaged even when physical forces are applied, making them suitable as roller materials for transfer printing. Furthermore, the metal mesh layer adheres well to the protrusions, thus facilitating easy transfer from the first sheet to the patterning roller.

[0090] Siloxane elastomers can be aliphatic polysiloxanes, aromatic polysiloxanes, or polysiloxane polymers comprising repeating siloxane units containing both aliphatic and aromatic groups, or independently containing both aliphatic and aromatic groups. As a non-limiting specific embodiment, aliphatic polysiloxanes can be selected from polydimethylsiloxane, polydiethylsiloxane, polymethylethylsiloxane, dimethylsiloxane-diethylsiloxane copolymer, dimethylsiloxane-ethylmethylsiloxane copolymer, etc., and aromatic polysiloxanes can be selected from polydiphenylsiloxane, polymethylphenylsiloxane, polyethylphenylsiloxane, (dimethylsiloxane-diphenylsiloxane) copolymer, etc. A polysiloxane comprising repeating siloxane units containing both aliphatic and aromatic groups, or individually each containing both aliphatic and aromatic groups, can refer to a form comprising repeating units of both aliphatic and aromatic siloxanes as exemplified above, or a form in which the aliphatic and aromatic substituents exemplified above are each combined with a silicon element located in one repeating unit, but is not limited thereto. As an example, siloxane elastomers can be used in the field of transferring fine patterns using soft-lithography, such as with stamps. An example of a polysiloxane from Dow Corning is a polysiloxane from... 184, etc., but not limited to this.

[0091] In one embodiment, the second sheet may have a surface coating with a hydrophilic surface treatment or a low Tg coating, or it may have a low Tg coating with a hydrophilic surface treatment. More specifically, the surface of the second sheet that contacts the patterning roller may be a hydrophilic surface-treated transparent sheet. Alternatively, the second sheet may include: a transparent substrate; and a coating formed on the surface of the transparent substrate that contacts the patterning roller. Alternatively, the second sheet may include: a transparent substrate; and a coating located on the surface of the transparent substrate that contacts the patterning roller and has undergone a hydrophilic surface treatment.

[0092] By utilizing a hydrophilic surface treatment to form a second sheet with hydrophilic functional groups, the patterned grid located on the patterning roller can be easily and readily transferred to the second sheet when the patterning roller comes into contact with the second sheet.

[0093] Hydrophilic surface treatment can be any method commonly used to modify polymer surfaces to be hydrophilic, such as corona treatment, plasma treatment, and / or ozone treatment. However, hydrophilic surface treatment is not limited to surface modification and can also be achieved by forming a primer layer with hydrophilic functional groups. The primer layer can be any primer material commonly used to form hydrophilic surfaces in existing transparent electrodes based on metal nanowires. Examples include monomers, oligomers, polymers, or combinations thereof of urethane acrylates, acryloyl acrylates, epoxy acrylates, urethanes, etc., but are not limited to these.

[0094] The coating can be a transparent polymer layer with a low glass transition temperature (Tg), specifically, the glass transition temperature (Tg) can be 80-140°C, more specifically 100-140°C, and even more specifically 100-130°C. For example... Figure 2As shown, during photonic sintering after patterning, a conductive mesh can be bonded to a second sheet simultaneously through a coating of a transparent polymer layer with low Tg. As an example, the transparent polymer layer may be one or a mixture of two or more of the following: polyester, polyethylene terephthalate (PET), acrylate (AC), polybutylene terephthalate (PB), polymethyl methacrylate (PMMA), acrylic resin, polycarbonate (PC), polystyrene, triacetate (TAC), polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, polyethylene, ethylenevinylacetate copolymer, polyvinyl butyral, metal ion-crosslinked ethylene-methacrylic acid copolymer, polyurethane, cellophane, and polyolefin, but is not limited thereto. As a more specific example, the transparent polymer layer can be made of one or more substances selected from nonionic polyurethane and acrylic polymers. In this case, the weight-average molecular weight of the transparent polymer can be between 1,000 and 500,000,000, but is not limited to this range. In specific examples of transparent polymer materials, various known methods can be used to achieve the physical properties that satisfy the proposed glass transition temperature, such as the type of substance, degree of polymerization, molecular weight distribution, mixing ratio of different substances, introduction of functional groups, additives, etc. Considering the application of patterned flexible electrodes, the thickness of the transparent polymer layer can be appropriately adjusted. As an example, the thickness of the transparent polymer layer (coating) can be from 50 nm to 10 μm, but is not limited to this range.

[0095] The first and second sheets (or transparent substrates) can be appropriately selected considering the intended use and specific process conditions. As examples, the first and second sheets (or transparent substrates) can be independently listed as follows: polyesters, such as polynaphthalene ester or polycarbonate; polyolefin films, such as linear, branched, and cyclic polyolefins; polyethylene films, such as polyvinyl chloride, polyvinylidene chloride, polyvinyl acetal, polystyrene, and polyacrylate; cellulose ester films, such as cellulose triacetate or cellulose acetate; polysulfone films, such as polyethersulfone; polyimide films; or silicon films, etc., but the present invention is not limited to the specific material of the sheets. The transmittance of the transparent sheet (or transparent polymer layer) to light with a wavelength of 550 nm can be above 90%, specifically above 93%, more specifically above 95%, and even more specifically above 97%.

[0096] The present invention includes a patterned flexible electrode manufactured by the above-described manufacturing method.

[0097] This invention provides a patterned flexible electrode having a patterned conductive mesh in which metal nanowires and metallic conductive fibers are mixed. Here, the metal nanowires correspond to the metal nanowires described in the manufacturing method, the metallic conductive fibers correspond to the conductive fibers obtained by sintering metallic fibers in the sintering step of the manufacturing method, the conductive mesh corresponds to the mesh obtained by photonic sintering of a fiber-nanowire mesh in the manufacturing method, and the pattern of the patterned conductive mesh corresponds to the pattern of the protrusions described in the manufacturing method. Therefore, the transparent electrode includes all the contents of the manufacturing method described above.

[0098] The patterned flexible electrode of the present invention comprises: a transparent sheet; a patterned electrode located on the transparent sheet, and comprising a conductive mesh containing metal nanowires and metallic conductive fibers, wherein, based on the electrode region where the patterned electrode is located in the transparent sheet, the nanowire filling factor, which is a proportion of the area covered by the metal nanowires, is 3-11%, the fiber filling factor, which is a proportion of the area covered by the conductive fibers, is 3-10%, and the mesh filling factor, which is a proportion of the area covered by the conductive mesh, is 9-13%.

[0099] In one embodiment of the patterned flexible electrode, the nanowire filling factor can be 3-5%, the conductive fiber filling factor can be 8-10%, and the conductive mesh filling factor can be 11-13%. In another embodiment of the patterned flexible electrode, the nanowire filling factor can be 8-11%, the conductive fiber filling factor can be 3-5%, and the mesh filling factor can be 11-13%. When the filling factors described above are met, the transparent electrode can have a transmittance of 90% or more, specifically 91% or more, and more specifically 92% or more. While possessing the excellent optical properties described above, when the unpatterned mesh layer is photonically sintered, it can exhibit excellent electrical properties with a sheet resistance of 1.9 Ω / sq or less, specifically 1.8 Ω / sq or less, and more specifically 1.7 Ω / sq or less.

[0100] Furthermore, in a patterned flexible electrode according to one embodiment, when photonic sintering is performed on an unpatterned grid layer, the increase rate of thin-film resistance can be less than 5% when 100,000 bending tests are conducted with a bending radius of 3 mm.

[0101] Furthermore, according to one embodiment, the transmittance of the patterned flexible electrode, based on the electrode area, can be over 90%, with a linear pattern having a line width of 1 mm (see reference). Figure 1 The sheet resistance based on ) can be below 80Ω / sq.

[0102] Furthermore, in a patterned flexible electrode according to one embodiment, when a linear pattern with a line width of 1 mm is used as a reference and a bending radius of 3 mm is used for 100,000 bending tests, the increase rate of thin film resistance can be less than 8%, specifically less than 7.5%.

[0103] The bending test can be performed using a conventional two-point bending tester with a radius of 3 mm. The width × length of the sample used for the bending test can be 5-30 cm × 5-30 cm horizontally.

[0104] The present invention includes a transparent electrode manufactured by the above-described manufacturing method or a display device including the above-described transparent electrode.

[0105] As one specific embodiment, the present invention includes a transparent electrode manufactured by the above-described manufacturing method or a liquid crystal display device including the above-described transparent electrode.

[0106] As one specific embodiment, the present invention includes a transparent electrode manufactured by the above manufacturing method or a touch panel including the above transparent electrode.

[0107] As one specific embodiment, the present invention includes a transparent electrode manufactured by the above-described manufacturing method or an electroluminescent device including the above-described transparent electrode.

[0108] As one specific embodiment, the present invention includes a transparent electrode manufactured by the above-described manufacturing method or a photovoltaic cell including the above-described transparent electrode.

[0109] As one specific embodiment, the present invention includes a transparent electrode manufactured by the above manufacturing method or an anti-static layer including the above transparent electrode.

[0110] As one specific embodiment, the present invention includes a transparent electrode manufactured by the above-described manufacturing method or a fingerprint recognition sensor including the above-described transparent electrode.

[0111] Figure 3 These are scanning electron microscope images of a conductive grid manufactured according to one embodiment of the present invention. Figure 4 These are scanning electron microscope images of the mesh portions between nanowires within a conductive mesh. More detailed... Figure 3 (and Figure 4 The conductive mesh was fabricated using a transparent electrode sample (sample 5 in Table 1) as follows: An Ag nanowire dispersion (80 nm diameter, 1000 aspect ratio) was coated onto a substrate (polyethylene terephthalate film) to form a nanowire mesh, achieving a nanowire filling factor of 9.5%. Then, 78 wt% silver nanoparticles (20 nm diameter) and a polyethylene oxide polymer liquid were electrospun onto the nanowire mesh using a coaxial dual nozzle to incorporate fibers (metallic fiber diameter = 1 μm), achieving a metallic fiber filling factor of 4.4%. The mesh was then washed with an organic solvent to remove the polyethylene oxide polymer sheath, creating a fiber-nanowire mesh. Finally, the mesh was subjected to a pulse width of 1500 μsec and a pulse strength of 1201.5 J / cm. 2 Transparent electrode samples (sample 5 in Table 1) were fabricated by irradiating the sample with white light pulses (300-1000 nm) at high intensity three times. At this time, the fill factor of the conductive mesh was 12.4%. The transmittance of the fabricated electrode was 91%, and the sheet resistance was 1.7 Ω / sq.

[0112] according to Figure 3 and Figure 4 It can be confirmed that conductive fibers were uniformly sintered without internal pores or surface cracks through photonic sintering, and it can be known that a conductive mesh was formed by the fusion of contact points between nanowires while the silver nanoparticles that produced the metallic fibers were being sintered.

[0113] In addition to incorporating the nanowires to achieve a nanowire filling factor of 4.2% when coating the first dispersion and a metallic fiber filling factor of 8.9% when electrospinning the second dispersion, the nanowires are also incorporated through... Figure 3 and Figure 4 The transparent electrode was fabricated using the same method as the sample (sample 3 in Table 1). The fill factor of the conductive mesh was 11.6%. The fabricated transparent electrode had a transmittance of 92% and a sheet resistance of 1.9 Ω / sq.

[0114] Similarly, transparent electrodes were fabricated by changing the nanowire filling factor (Wir.FF) when coating the first dispersion and the metallic fiber filling factor (Fib.FF) when electrospinning the second dispersion, and the conductive mesh filling factor (Net.FF), transmittance and thin-film resistance of the transparent electrodes are summarized and shown in Table 1.

[0115] (Table 1)

[0116] Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Sample 7 Sample 8 Sample 9 Nanowire filling factor (%) 4.2 4.2 4.2 9.5 9.5 9.5 14.1 14.1 14.1 Fiber filling factor (%) 2.1 4.4 8.9 2.1 4.4 8.9 2.1 4.4 8.9 Mesh fill factor (%) 4.8 8.9 11.6 10.1 12.4 16.9 14.7 17 21.5 Transmission rate (%) 95 94 92 93 91 87 89 86 82 Thin film resistance (Ω / sq) 9.5 3.1 1.9 7.9 1.7 1.4 7.5 1.5 1.3

[0117] According to Table 1, it can be seen that when the nanowire filling factor is 3-5% and the conductive fiber filling factor is 8-10%, and when the nanowire filling factor is 8-11% and the conductive fiber filling factor is 3-5%, it can simultaneously have excellent transparency of more than 91% light transmittance and excellent electrical properties of less than 1.9Ω / sq.

[0118] Figure 5 This is a graph showing the sheet resistance measured according to the number of bends after subjecting a manufactured transparent electrode (sample 5) to 100,000 bending tests with a curvature radius of 3 mm. According to... Figure 5 It can be seen that the sheet resistance after 100,000 bending tests is 1.76Ω / sq, and the resistance increase rate [=(sheet resistance after 100,000 bending tests - sheet resistance immediately after manufacturing) / (sheet resistance immediately after manufacturing)×100] is only 3.5%.

[0119] For comparison, a transparent electrode (comparative sample 1) was fabricated using the same method and filling factor as sample 5, except that the second dispersion was first electrospun and washed with an organic solvent to create a fiber mesh, and then the first dispersion containing nanowires was coated onto the fiber mesh and photonic sintered. While the fabricated transparent electrode (comparative sample 1) showed similar transmittance to sample 5, its sheet resistance increased to 2.0 Ω / sq, and a significant increase to 4.7 Ω / sq was confirmed during 100,000 bending tests at a curvature radius of 3 mm.

[0120] In addition, besides electrospinning the second dispersion and washing it with an organic solvent to create a fiber mesh, then heat-treating it at 200°C for 2 hours to transform the metallic fiber mesh into a conductive fiber mesh, and then coating the first dispersion containing nanowires onto the conductive fiber mesh and performing photonic sintering in the same manner, a transparent electrode (comparative sample 2) was fabricated using the same method and the same filling factor as sample 5. Although the fabricated transparent electrode (comparative sample 2) showed similar transmittance to sample 5, its sheet resistance increased to 1.8 Ω / sq, and it was confirmed that the sheet resistance increased to 2.3 Ω / sq after 100,000 bending tests at a radius of curvature of 3 mm.

[0121] Figure 6 This is a graph showing the increase in sheet resistance (sheet resistance after bending test / sheet resistance before bending test, normalized sheet resistance) as measured by the number of bending cycles after subjecting a patterned flexible electrode manufactured as follows to 100,000 bending tests with a radius of curvature of 3 mm. Figure 2 The flowchart describes a process where a polydimethylsiloxane patterning roller with protrusions is used to transfer 1 mm wide linear electrodes arranged parallel to each other at 1 mm intervals. A polyethylene terephthalate (PET) film is used as the first sheet, and an ozone-treated PET film is used as the second sheet. A pressure roller is used, applying 500 kPa when the patterning roller contacts the first sheet and 100 kPa when the patterning roller contacts the second sheet, to transfer an unsintered fiber-nanowire mesh pattern onto the second sheet. Photonic sintering is then performed to fabricate a patterned flexible electrode. The conditions for nanowire formation, fiber formation, and photonic sintering are the same as those for sample 5. Through micro-patterning, the sheet resistance increases to 79 Ω / sq, but it can be confirmed that the resistance increase rate after 100,000 bending tests is only 7.48% when linear patterning with a width of 1 mm is performed.

[0122] As described above, the present invention has been illustrated with specific content, limited embodiments, and drawings. However, this is only provided to help to understand the present invention more fully. The present invention is not limited to the above embodiments, and those skilled in the art can make various modifications and variations based on this description.

[0123] Therefore, the concept of this invention should not be limited to the described embodiments, and all claims of this invention and all contents that are equivalent or have equivalent variations to the claims are within the scope of this invention.

Claims

1. A method of manufacturing a patterned flexible electrode, comprising: a nanowire forming step of applying a first dispersion liquid containing metal nanowires on a first sheet unwound from a roll state to form a nanowire mesh; a fiber forming step of electrospinning a second dispersion liquid containing metal nanoparticles onto the nanowire mesh to form a fiber-nanowire mesh in which metal nanoparticle aggregates are mixed into the metal fibers of the nanowire mesh; and a sintering step of sintering the fiber-nanowire mesh by photonic sintering to form a conductive mesh, and a patterning step in which the fiber-nanowire mesh is patterned by a patterning roll before the sintering step or the conductive mesh is patterned after the sintering step, wherein in the patterning step, a patterning roll having a protrusion portion is rotated and brought into contact with the first sheet and a second sheet as a transparent sheet unwound from a roll state, respectively, the fiber-nanowire mesh or the conductive mesh is patterned in the shape of the protrusion portion and transferred to the patterning roll by the contact of the first sheet with the patterning roll, and the patterned mesh on the patterning roll is transferred to the second sheet by the contact of the patterning roll with the second sheet.

2. The method of manufacturing a patterned flexible electrode according to claim 1, wherein, The protrusion portion of the patterning roll is a silicone elastomer.

3. The method of manufacturing a patterned flexible electrode according to claim 1, wherein, A first pressure roll and a second pressure roll are provided so as to be opposed to each other with the first sheet interposed therebetween and so as to be opposed to each other with the second sheet interposed therebetween, respectively, and pressure is applied to the first sheet when the first sheet is brought into contact with the patterning roll and to the second sheet when the second sheet is brought into contact with the patterning roll.

4. The method of manufacturing a patterned flexible electrode according to claim 1, wherein, At least a surface of the second sheet which comes into contact with the patterning roll is subjected to a corona treatment, a plasma treatment, or an ozone treatment.

5. The method of manufacturing a patterned flexible electrode according to claim 1, wherein, Drying is performed immediately after the nanowire forming step or after the fiber forming step by irradiation of light including ultraviolet rays, application of hot air or dry air, or heating.

6. The method of manufacturing a patterned flexible electrode according to claim 1, wherein, In the fiber forming step, a coaxial double nozzle including an inner nozzle and an outer nozzle surrounding the inner nozzle is used in electrospinning, the second dispersion liquid is spun through the inner nozzle, and a polymer solution is spun through the outer nozzle to form a composite fiber in which the metal fiber is wrapped in a polymer sheath.

7. The method of manufacturing a patterned flexible electrode according to claim 6, wherein, A step of removing the polymer sheath from the composite fiber is further included after the electrospinning.

8. The method of manufacturing a patterned flexible electrode according to claim 1, wherein, The metal fiber is converted into a conductive fiber by sintering in the sintering step, and fusion is achieved between the fibers and the nanowires of the fiber-nanowire mesh and between the nanowires.

2. The method of manufacturing a patterned flexible electrode according to claim 1, wherein the protrusion portion of the patterning roll is a silicone elastomer.

3. The method of manufacturing a patterned flexible electrode according to claim 1 or 2, wherein a first pressure roll and a second pressure roll are provided so as to be opposed to each other with the first sheet interposed therebetween and so as to be opposed to each other with the second sheet interposed therebetween, respectively, and pressure is applied to the first sheet when the first sheet is brought into contact with the patterning roll and to the second sheet when the second sheet is brought into contact with the patterning roll.

4. The method of manufacturing a patterned flexible electrode according to any one of claims 1 to 3, wherein at least a surface of the second sheet which comes into contact with the patterning roll is subjected to a corona treatment, a plasma treatment, or an ozone treatment.

5. The method of manufacturing a patterned flexible electrode according to any one of claims 1 to 4, wherein drying is performed immediately after the nanowire forming step or after the fiber forming step by irradiation of light including ultraviolet rays, application of hot air or dry air, or heating.

6. The method of manufacturing a patterned flexible electrode according to any one of claims 1 to 5, wherein in the fiber forming step, a coaxial double nozzle including an inner nozzle and an outer nozzle surrounding the inner nozzle is used in electrospinning, the second dispersion liquid is spun through the inner nozzle, and a polymer solution is spun through the outer nozzle to form a composite fiber in which the metal fiber is wrapped in a polymer sheath.

7. The method of manufacturing a patterned flexible electrode according to claim 6, wherein a step of removing the polymer sheath from the composite fiber is further included after the electrospinning.

8. The method of manufacturing a patterned flexible electrode according to any one of claims 1 to 7, wherein the metal fiber is converted into a conductive fiber by sintering in the sintering step, and fusion is achieved between the fibers and the nanowires of the fiber-nanowire mesh and between the nanowires.

9. The method of manufacturing a patterned flexible electrode according to claim 1, wherein, In the nanowire forming step, a nanowire filling factor, which is a proportion of an area covered by the metal nanowires in the area of the first sheet, is 3-11%, a fiber filling factor, which is a proportion of an area covered by the metallic fibers, is 3-10%, and a mesh filling factor, which is a proportion of an area covered by the fiber-nanowire mesh, is 9-13%.

10. The method of manufacturing a patterned flexible electrode according to claim 1, wherein, The photonic sintering is performed by irradiation of a pulsed white light having an intensity of 800-1600 J / cm 2 .

11. The method of manufacturing a patterned flexible electrode according to claim 1, wherein, A ratio of a diameter of the metallic fibers to a diameter of the metal nanowires is 10-1000.

12. The method of manufacturing a patterned flexible electrode according to claim 1, wherein, The metallic fibers and the metal nanowires each comprise silver (Ag), gold (Au), aluminum (Al), copper (Cu), chromium (Cr), nickel (Ni), iron (Fe), or an alloy thereof.

13. A patterned flexible electrode made according to the method of any one of claims 1-12, comprising: A transparent sheet; A patterned electrode, which is located on the transparent sheet and includes a conductive mesh in which metal nanowires and metallic conductive fibers are mixed, In an electrode region of the transparent sheet in which the patterned electrode is located, a nanowire filling factor, which is a proportion of an area covered by the metal nanowires, is 3-11%, a fiber filling factor, which is a proportion of an area covered by the conductive fibers, is 3-10%, and a conductive mesh filling factor, which is a proportion of an area covered by the conductive mesh, is 9-13%.

14. The patterned flexible electrode of claim 13, wherein, The patterned flexible electrode has a light transmittance of 90% or more with respect to an electrode region, and a sheet resistance of 80 Ω / sq or less with respect to a linear pattern having a line width of 1 mm.

15. The patterned flexible electrode of claim 13, wherein, When a bending test is performed 100,000 times with respect to the patterned flexible electrode, with a bending radius of 3 mm, with respect to a linear pattern having a line width of 1 mm, an increase rate of the sheet resistance is 8% or less.

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