Electrode, device, and method for manufacturing electrode

Abstract

To provide an electrode capable of suppressing an increase in resistance of the electrode of a device even when the device is expanded and contracted.SOLUTION: An electrode comprising at least a substrate, a binder layer, and a conductive layer in this order, wherein the conductive layer contains a metal nanowire and a conductive polymer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electrode, a device, and a method for manufacturing an electrode. [Background technology]

[0002] An electrochromic device is a device that utilizes the property of an electrochromic material that changes color through an oxidation-reduction reaction, and has a pair of electrodes and an electrochromic layer positioned between them.

[0003] For example, Patent Document 1 discloses a low-resistance transparent porous electrode that is made by stacking a transparent porous conductive film, a metal thin film that is transparent to visible light, and an oxide thin film that is transparent to visible light and conductive, with the aim of achieving a high-speed electrochromic reaction at a low voltage. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-065994 Summary of the Invention [Problem to be solved by the invention]

[0005] However, metal thin films such as silver thin films and oxide thin films such as fluorine tin oxide thin films that are transparent to visible light have poor durability against deformation, and therefore, when such electrodes are used in devices such as flexible displays that have flexibility and stretchability, deformation can increase electrical resistance or cause the electrodes to break.

[0006] The present invention has been made in consideration of the above problems, and aims to provide an electrode that can suppress an increase in the resistance of the electrode of a device even when the device is stretched or contracted. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result have found that the above-mentioned problems can be solved by an electrode including a base material, a binder layer, and a conductive layer, at least in this order, in which the conductive layer contains metal nanowires and a conductive polymer, thereby completing the present invention.

[0008] That is, the present invention is as follows. [1] A substrate, a binder layer, and a conductive layer are provided at least in this order; the conductive layer includes metal nanowires and a conductive polymer; electrode. [2] the metal nanowires include silver nanowires; [1] The electrode according to [1]. [3] The conductive polymer includes a thiophene-based polymer. The electrode according to [1] or [2]. [4] the conductive layer has a first conductive layer containing the conductive polymer, a second conductive layer containing the conductive polymer, and a metal nanowire-containing layer containing the metal nanowires and located between the first conductive layer and the second conductive layer; The electrode according to any one of [1] to [3]. [5] the binder layer contains one or more resins selected from the group consisting of epoxy-based resins, urethane-based resins, and polyamide-based resins; The electrode according to any one of [1] to [4]. [6] The thickness of the binder layer is 10 μm or less. The electrode according to any one of [1] to [5]. [7] The resistance per unit length of the electrode when the elongation rate is 0% is 250 Ω / cm or less. The electrode according to any one of [1] to [6]. [8] The resistance per unit length of the electrode when the elongation rate is 60% is 1000 Ω / cm or less. The electrode according to any one of [1] to [7]. [9] When the electrode is stretched and the resistance of the electrode becomes 60 MΩ / cm or more, the elongation rate of the electrode is 250% or more. The electrode according to any one of [1] to [8].

[10] The visible light transmittance of the electrode when no voltage is applied is 10% or more. The electrode according to any one of [1] to [9].

[11] The electrode according to any one of [1] to

[10] , which is used in an electrochromic device.

[12] A first electrode; A second electrode; an electrochromic layer located between the first electrode and the second electrode; The first electrode and / or the second electrode is the electrode according to any one of [1] to

[11] . device.

[13] a binder layer forming step of applying one or more resins selected from the group consisting of epoxy resins, urethane resins, and polyamide resins onto a substrate to form a binder layer; and a conductive layer forming step of applying one or more liquids in which a conductive polymer and / or metal nanowires are dispersed onto the binder layer to form a conductive layer. Electrode manufacturing method.

[14] The conductive layer forming step a first conductive layer forming step of applying a liquid in which the conductive polymer is dispersed onto the binder layer to form a first conductive layer; a metal nanowire-containing layer forming step of applying a liquid in which the metal nanowires are dispersed onto the first conductive layer to form a metal nanowire-containing layer; a second conductive layer forming step of applying a liquid in which the conductive polymer is dispersed onto the metal nanowire-containing layer to form a second conductive layer; having

[13] A method for producing an electrode according to

[13] . [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an electrode that can suppress an increase in the resistance of the electrode of a device even when the device is stretched or contracted. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a cross-sectional view showing an example of the configuration of an electrode. [Figure 2] FIG. 2 is a cross-sectional view showing an example of the configuration of a device. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail with reference to the drawings as necessary, but the present invention is not limited to this, and various modifications are possible without departing from the spirit of the present invention. In the drawings, the same elements are given the same reference numerals, and redundant explanations will be omitted. Furthermore, positional relationships such as up, down, left, and right will be based on the positional relationships shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios of the drawings are not limited to those shown in the drawings.

[0012] 1. Electrode Fig. 1 is a cross-sectional view showing an example of the configuration of electrode 1. As shown in Fig. 1, electrode 1 includes a substrate 10, a conductive layer 12 disposed on one surface of substrate 10, and a binder layer 14 between substrate 10 and conductive layer 12, and conductive layer 12 includes a conductive polymer and metal nanowires.

[0013] The conductive layer 12 may be a single layer containing a conductive polymer and metal nanowires, or may have a conductive layer 120 containing a conductive polymer and a metal nanowire-containing layer 122 containing metal nanowires, as shown in FIG. 1 . The conductive layer 12 may also have a three-layer structure including a first conductive layer 120A, a metal nanowire-containing layer 122 on the first conductive layer 120A, and a second conductive layer 120B on the metal nanowire-containing layer 122. Alternatively, although not shown, the conductive layer may have a three-layer structure in which a conductive layer is located between two metal nanowire-containing layers. With such a three-layer structure, when the conductive layer is bent in either direction or stretched, the outer layers can more easily compensate for the conductivity of the central layer, which tends to further improve deformation durability.

[0014] The electrode 1 includes a conductive layer 12 containing metal nanowires and a conductive polymer. Nanowires are wires with diameters on the order of nanometers. The length of the nanowires is not particularly limited, but the ratio of the length to the diameter (length / diameter) is, for example, 10 to 100,000. Although a single metal nanowire is small, the electrical conductivity of the metal nanowire-containing layer 122 is maintained by the gathering of numerous metal nanowires and the complex contact between the nanowires. Furthermore, even if the metal nanowire-containing layer 122 is deformed, only the contact points between the nanowires within the layer change, and the electrical conductivity of the electrode as a whole is maintained. Therefore, compared to metal foil layers that are prone to cracking or breaking due to deformation, the electrode 1 having the metal nanowire-containing layer 122 tends to have excellent durability against deformation.

[0015] Furthermore, the conductive layer 12 contains a conductive polymer. This allows conductivity in the conductive layer 12 to be achieved not only by contact between the metal nanowires but also by contact between the metal nanowires and the conductive polymer and between the conductive polymers. That is, by containing the conductive polymer in the conductive layer 12, the number of conductive paths in the conductive layer 12 increases. With this increase in conductive paths, the conductive polymer maintains electrical conductivity, particularly when the electrode 1 is deformed and the nanowires are partially disconnected from each other. Therefore, the electrode 1 tends to have a resistance that is less likely to change even when deformed, and has excellent durability against deformation.

[0016] The electrode 1 also includes a binder layer 14 between the substrate 10 and the conductive layer 12. When the electrode 1 is stretched, a restoring force acts on the substrate 10 to return it to its original length, and this restoring force is transmitted to the binder layer 14 in contact with the substrate 10. Here, because the binder layer 14 is flexible, this restoring force is alleviated by the binder layer 14 and is less likely to be transmitted to the conductive layer 12, thereby preventing the conductive layer 12 from cracking or breaking due to this restoring force. Therefore, the electrode 1 tends to have excellent durability against deformation.

[0017] Furthermore, the high deformation durability of electrode 1 and the high conductivity of conductive layer 12 can reduce the voltage required to operate a device equipped with electrode 1, thereby realizing energy savings in the device.

[0018] From the viewpoint of improving the color development of the device, the electrode 1 is preferably transparent to visible light (light having a wavelength of 400 to 800 nm). For example, the visible light transmittance in the thickness direction of the electrode 1 is 10% or more, 10 to 100%, 15 to 100%, 20 to 100%, or 25 to 100%. Alternatively, the transmittance of light with a wavelength of 555 nm in the thickness direction of the electrode 1 is preferably 10% or more, 10 to 100%, 15 to 100%, 20 to 100%, or 25 to 100%. The thickness direction refers to the stacking direction of the substrate 10, binder layer 14, and conductive layer 12.

[0019] When no horizontal tension is applied to electrode 1, i.e., when the elongation rate is 0%, the resistance R0 per unit length of electrode 1 is preferably 250 Ω / cm or less, 0 to 250 Ω / cm, or 5 to 225 Ω / cm. When the resistance is within the above range, a small voltage is required to operate a device including electrode 1, which tends to improve the energy saving properties of the device.

[0020] Resistance R per unit length of electrode 1 when horizontal tension is applied to electrode 1 and the elongation rate is 60% 60 is preferably 1000 Ω / cm or less, 0 to 1000 Ω / cm, 50 to 750 Ω / cm, or 50 to 500 Ω / cm. When the resistance is within the above range, even when a device including electrode 1 is used in a stretching environment, a small voltage is required to operate the device, which tends to improve the energy saving properties of the device.

[0021] Resistance R to resistance R0 60 The ratio (R 60 / R0) is preferably 1.0 to 20.0, 1.1 to 15.0, or 1.2 to 10.0. 60 / R0) within the above range tends to improve the energy saving properties of the device.

[0022] When the resistance of electrode 1 becomes 60 MΩ / cm or more by stretching in the horizontal direction, the elongation percentage of electrode 1 is preferably 250% or more, 250 to 1000%, 260 to 1000%, 270 to 1000%, or 280 to 1000%. When the elongation percentage is within the above range, devices including electrode 1 tend to be usable in environments where stretching is more likely.

[0023] In addition to the metal nanowires, which have excellent deformation durability and conductivity, the electrode 1 of this embodiment also contains a conductive polymer that compensates for the conductive path even when excessive deformation prevents current flow through the metal nanowires. This allows the electrode 1 to reduce not only the resistance at 0% elongation but also the resistance per unit length at high elongation. Further reduction in resistance can be achieved by adjusting the amount of metal nanowires or conductive polymer used or the layer thickness, or by using a material that is both flexible and highly conductive. The same applies to the elongation at which the resistance of the electrode 1 becomes 60 MΩ / cm or higher.

[0024] In this embodiment, unless otherwise specified, the resistance is a value measured at room temperature (25° C.).

[0025] In this embodiment, 25°C is used as a reference value for the temperature when the electrode 1 is used. In this regard, it is expected that the electrode 1 may be used at temperatures higher or lower than 25°C depending on the environment in which the electrode 1 is used. However, even if the temperature when the electrode 1 is actually used is not 25°C but is higher or lower than this, it can be said that the energy saving properties of a device including the electrode 1 can be improved if the resistance measured with 25°C as the reference falls within a predetermined range.

[0026] In this embodiment, the elongation of electrode 1 is measured at 0% and 60%. Being able to measure the resistance at an elongation of 60% means that the electrode itself can be stretched to 60% without breaking, and that even when stretched to 60%, the electrode does not break internally and maintains conductivity. In other words, the resistance at an elongation of 60% is one criterion for determining the deformation durability of the electrode, and does not mean that the use of the electrode is limited to an elongation of 60%.

[0027] Furthermore, in this embodiment, the elongation of electrode 1 is measured when the resistance of electrode 1 is 60 MΩ / cm or more. In this regard, it is conceivable that even electrodes with a resistance of 60 MΩ / cm or more can be applied to devices, or that only electrodes with a resistance of less than 60 MΩ / cm can be applied to devices. However, even if the applicability of an electrode to a device is not determined based on 60 MΩ / cm in an actual device including electrode 1, if the elongation of electrode 1 measured based on 60 MΩ / cm falls within a predetermined range, it can be said that a device including electrode 1 can be used in an environment where elongation is more likely to occur.

[0028] The electrode 1 of this embodiment has excellent durability against deformation and is therefore suitable for use in electrochromic devices that change color when a voltage is applied. Electrochromic devices are used in environments where the device is prone to deformation. For example, electronic paper, which is an electrochromic device, can be deformed by applying pressure with a human finger or pen. Furthermore, light-control glass, which is an electrochromic device, is used in environments where temperature changes are large due to sunlight, etc. Large temperature changes can cause large volume changes in the light-control glass, resulting in deformation.

[0029] The total thickness of the electrode 1, which is the sum of the substrate, conductive layer, and binder layer, is preferably 0.01 to 1.5 mm, and more preferably 0.01 to 1.3 mm. When the total thickness of the electrode 1 is within the above range, the electrode 1 tends to have both good conductivity and transparency.

[0030] Each component of the electrode 1 will be described in detail below.

[0031] 1.1. Base material The electrode 1 of this embodiment includes a substrate 10. In a display device in which pixels are arranged on a plane, electrodes are arranged above and below the pixels, such as an electrochromic layer, in the thickness direction, with the pixels sandwiched between the pair of electrodes. Therefore, at least one of the electrodes is configured to be transparent so that light emitted from the pixels can be extracted. Therefore, when the electrode 1 is used as a transparent electrode in a display device such as an electrochromic device, the substrate 10 is preferably transparent to visible light. More specifically, the transmittance of visible light in the thickness direction of the substrate 10 is preferably 50% or more, 50 to 100%, or 60 to 100%. Alternatively, the transmittance of light with a wavelength of 555 nm in the thickness direction of the substrate 10 is preferably 50% or more, 50 to 100%, or 60 to 100%.

[0032] The substrate 10 is not particularly limited, but may include, for example, glass, quartz, a semiconductor, or a resin. Among these, glass or resin is preferred from the viewpoints of transparency and cost, and resin is preferred from the viewpoints of flexibility and stretchability. The resin is preferably a transparent resin that is transparent to visible light or has a visible light transmittance of 50% or more. The transparent resin is not particularly limited, but examples thereof include episulfide-based copolymers, thiourethane-based copolymers, acrylic-based copolymers, polycarbonate-based copolymers, urethane-based copolymers, polyamide-based copolymers, polyester-based copolymers, cellulose-based copolymers, cycloolefin polymers, cycloolefin copolymers, norbornene-based copolymers, and silicone-based copolymers. The transparent resin is preferably an acrylic-based copolymer.

[0033] The resin content in the substrate 10 is preferably 70 to 100 mass %, 80 to 100 mass %, or 90 to 100 mass % relative to the total amount of the substrate 10, and may consist essentially of resin or may consist only of resin. When the resin content in the substrate 10 is within the above range, the transparency and flexibility of the electrode 1 tend to be improved.

[0034] The Young's modulus of the acrylic copolymer at room temperature is preferably 2.0 MPa or less, 0.0 to 2.0 MPa, 0.1 to 1.5 MPa, or 0.2 to 1.0 MPa. When the Young's modulus of the acrylic copolymer is within the above range, the deformation durability of the electrode 1 tends to be further improved. The Young's modulus can be measured, for example, in accordance with JIS K 7161.

[0035] The tensile elongation of the substrate at room temperature is preferably 100 to 2000%, 200 to 1800%, 300 to 1600%, or 400 to 1400%. When the tensile elongation of the substrate is within the above range, the substrate is less likely to break and its deformation durability tends to be further improved. The tensile elongation is the maximum elongation when the substrate is stretched until it breaks, and can be measured, for example, in accordance with JIS C 2151.

[0036] The thickness of the substrate 10 is preferably 0.01 to 1 mm. When the thickness of the substrate 10 is within the above range, the transparency of the substrate 10 tends to be improved.

[0037] 1.2.Conductive Layer The electrode 1 of this embodiment includes a conductive layer 12. When the electrode 1 is used as a transparent electrode of a display device such as an electrochromic device, the conductive layer 12 is preferably transparent to visible light. More specifically, the transmittance of the conductive layer 12 in the thickness direction of visible light is preferably 10% or more, 10 to 100%, or 15 to 100%. Alternatively, the transmittance of the conductive layer 12 in the thickness direction of light with a wavelength of 555 nm is preferably 10% or more, 10 to 100%, or 15 to 100%.

[0038] The conductive layer 12 contains metal nanowires and a conductive polymer. The metal nanowires and the conductive polymer have high conductivity. As described above, when the electrode 1 is applied to an electrochromic device, the conductive layer 12 is preferably transparent. On the other hand, from the viewpoint of improving the conductivity of the conductive layer 12 and improving the energy saving of a device including the electrode 1, it is preferable to increase the content of the conductive polymer and metal nanowires in the conductive layer 12.

[0039] Here, if the content of metal nanowires in the conductive layer 12 is increased too much, the conductive layer 12 may become colored. On the other hand, conductive polymers tend to be transparent to visible light, and even if the content of the conductive polymer in the conductive layer 12 is increased, the transparency of the conductive layer 12 is unlikely to decrease. In other words, by including a conductive polymer in the conductive layer 12, it tends to be possible to achieve both conductivity and transparency of the conductive layer 12.

[0040] The content of the metal nanowires and the conductive polymer is preferably 60 to 100 mass %, 70 to 100 mass %, 80 to 100 mass %, 90 to 100 mass %, or 95 to 100 mass % relative to the total amount of the conductive layer 12, and the conductive layer 12 may consist essentially of the metal nanowires and the conductive polymer, or may consist of the metal nanowires and the conductive polymer. When the content of the metal nanowires and the conductive polymer is within the above range, the conductivity of the conductive layer 12 tends to be further improved.

[0041] The thickness of the conductive layer 12 is preferably 10 μm or less, and is preferably 0.05 to 10 μm. When the thickness of the conductive layer 12 is within the above range, the transparency of the conductive layer 12 tends to be improved.

[0042] <Metal nanowires> Examples of metal nanowires include gold nanowires, silver nanowires, copper nanowires, aluminum nanowires, and nickel nanowires. Among these, silver nanowires are preferred from the viewpoint of achieving both high conductivity and low cost. The metal nanowires may be used singly or in combination of two or more types.

[0043] The content of the metal nanowires is preferably 20.0 to 60.0 mass%, 25.0 to 55.0 mass%, or 27.5 to 50.0 mass% relative to the total amount of the conductive layer 12. When the content of the metal nanowires is within the above range, the conductivity of the conductive layer 12 tends to be further improved.

[0044] <Conductive polymer> The conductive polymer is preferably a transparent conductive polymer that is transparent to visible light. More specifically, the visible light transmittance in the thickness direction of a 0.1 μm-thick thin film made of the conductive polymer is preferably 50% or more, 50 to 100%, or 60 to 100%. Furthermore, the light transmittance in the thickness direction of a 0.1 μm-thick thin film made only of the conductive polymer is preferably 50% or more, 50 to 100%, or 60 to 100% at a wavelength of 555 nm.

[0045] Examples of conductive polymers include polyacetylene-based polymers and polythiophene-based polymers, with polythiophene-based polymers being preferred. Examples of polythiophene-based polymers include polyethylenedioxythiophene-based polymers. More specifically, examples of polyethylenedioxythiophene-based polymers include polyethylenedioxythiophene with added polystyrene sulfonic acid (PEDOT / PSS). The conductive polymers may be used alone or in combination of two or more.

[0046] The content of the conductive polymer is preferably 35.0 to 80.0 mass %, 37.5 to 75.0 mass %, or 40.0 to 70.0 mass % relative to the total amount of the conductive layer 12. When the content of the conductive polymer is within the above range, the conductive layer 12 tends to have both good conductivity and transparency.

[0047] In the conductive layer 12, the content W of the metal nanowires M Conductive polymer W O The ratio of the content of (W O / W M) is preferably 1.1 to 2.0, 1.2 to 1.8, or 1.3 to 1.6. When the ratio is within the above range, the conductive layer 12 tends to have a better balance between conductivity and transparency.

[0048] <Other additives> The conductive layer 12 may or may not contain other additives in addition to the metal nanowires and conductive polymer. Examples of such additives include, but are not limited to, a binder for fixing the metal nanowires and conductive polymer, a thickener, and an antioxidant. When the conductive layer 12 contains other additives, the content of the other additives relative to the total amount of the conductive layer 12 is, but is not limited to, 0.1 to 20.0 mass %, for example.

[0049] In the conductive layer 12, the metal nanowires and the conductive polymer may be uniformly mixed together or unevenly distributed relative to each other. Alternatively, in the conductive layer 12, the metal nanowires may be unevenly distributed within the conductive polymer. When the metal nanowires and the conductive polymer are unevenly distributed relative to each other, or when the metal nanowires are unevenly distributed within the conductive polymer, the conductive layer 12 comprises a metal nanowire-containing layer containing the metal nanowires and a conductor layer containing the conductive polymer. When the metal nanowire-containing layer is present between two conductor layers, one conductor layer is referred to as the first conductor layer and the other conductor layer is referred to as the second conductor layer. In this embodiment, the layer containing the metal nanowires and the conductive polymer is referred to as the metal nanowire-containing layer.

[0050] Below, we will explain in detail the case where the conductive layer 12 has a first conductive layer 120A containing a conductive polymer, a second conductive layer 120B containing a conductive polymer, and a metal nanowire-containing layer 122 containing metal nanowires, located between the first conductive layer 120A and the second conductive layer 120B.

[0051] 1.2.1. First Conductive Layer The first conductive layer 120A has high conductivity because it contains a conductive polymer. The content of the conductive polymer in the first conductive layer 120A is preferably 60 to 100 mass %, 70 to 100 mass %, 80 to 100 mass %, 90 to 100 mass %, or 95 to 100 mass %, and the first conductive layer 120A may consist essentially of a conductive polymer, or may consist of only a conductive polymer. When the content of the conductive polymer is within the above range, the conductivity of the conductive layer 12 tends to be improved.

[0052] The thickness of the first conductive layer 120A is preferably 10 μm or less, and is preferably 0.01 to 10 μm. When the thickness of the first conductive layer 120A is within the above range, the deformation durability of the electrode 1 tends to be further improved.

[0053] 1.2.2. Second Conductive Layer The second conductive layer 120B has high conductivity because it contains a conductive polymer. The content of the conductive polymer in the second conductive layer 120B is preferably 60 to 100 mass %, 70 to 100 mass %, 80 to 100 mass %, 90 to 100 mass %, or 95 to 100 mass %, and the second conductive layer 120B may consist essentially of a conductive polymer, or may consist of only a conductive polymer. When the content of the conductive polymer is within the above range, the conductivity of the conductive layer 12 tends to be improved.

[0054] The thickness of the second conductive layer 120B is preferably 10 μm or less, and is preferably 0.01 to 10 μm. When the thickness of the second conductive layer 120B is within the above range, the deformation durability of the electrode 1 tends to be further improved.

[0055] 1, in one embodiment, the second conductive layer 120B constitutes the exposed surface of the electrode 1 and comes into contact with an object to which a voltage is applied by the electrode 1. At this time, sufficient contact between the object and the electrode 1 tends to reduce the interfacial resistance. In this regard, the second conductive layer 120B does not contain metal nanowires, and therefore tends to improve the smoothness of the exposed surface of the electrode 1. In other words, by including the second conductive layer 120B in the electrode 1, the interfacial resistance tends to be reduced, and the energy saving properties of a device including the electrode 1 tend to be improved.

[0056] 1.2.3. Metal nanowire-containing layer The metal nanowire-containing layer 122 contains metal nanowires. Therefore, as described above, the electrode 1 having the metal nanowire-containing layer 122 tends to be less susceptible to an increase in resistance even when deformed, and the electrode 1 tends to have excellent durability against deformation. The metal nanowire-containing layer 122 may contain a conductive polymer.

[0057] Furthermore, the metal nanowire content in the metal nanowire-containing layer 122 is preferably 60 to 100 mass %, 70 to 100 mass %, 80 to 100 mass %, 90 to 100 mass %, or 95 to 100 mass %, and may consist essentially of metal nanowires or may consist of metal nanowires. When the metal nanowire content is within the above range, the electrode 1 tends to have better durability against deformation.

[0058] The thickness of the metal nanowire-containing layer 122 is preferably 10 μm or less, and is preferably 0.01 to 10 μm. When the thickness of the metal nanowire-containing layer 122 is within the above range, the conductivity of the electrode 1 tends to be further improved.

[0059] 1.3.Binder layer When the electrode 1 is applied to an electrochromic device, the device includes an electrochromic layer. The electrochromic layer typically contains a solvent such as acetone, and such a solvent may penetrate from the electrochromic layer into the electrode 1. If the solvent penetrates into the substrate 10 of the electrode 1, the substrate 10 may be dissolved or altered by the solvent. As a result, the substrate 10 may peel off from the conductive layer 12 or the transparency of the substrate 10 may deteriorate. In this regard, by including the binder layer 14 in the electrode 1, the penetration of the solvent into the substrate 10 is inhibited, and the substrate 10 is likely to be inhibited from being dissolved or altered by the solvent. In other words, the solvent resistance of the electrode 1 tends to be improved.

[0060] The binder layer 14 preferably contains a resin, and the resin is preferably one or more selected from the group consisting of epoxy resins, urethane resins, and polyamide resins. The resins may be used alone or in combination of two or more. Among these, polyamide resins are preferred from the viewpoint of further improving solvent resistance.

[0061] The epoxy resin is not particularly limited, and examples thereof include bisphenol A type epoxy resin, bisphenol E type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, bisphenol A novolac type epoxy resin, glycidyl ester type epoxy resin, triglycidyl isocyanurate, aralkyl novolac type epoxy resin, biphenyl aralkyl type epoxy resin, naphthylene ether type epoxy resin, cresol novolac type epoxy resin, xylene novolac type epoxy resin, dicyclopentadiene novolac type epoxy resin, biphenyl novolac type epoxy resin, phenol Examples of the epoxy resin include aralkyl novolac epoxy resins, naphthol aralkyl novolac epoxy resins, polyfunctional phenol epoxy resins, naphthalene epoxy resins, anthracene epoxy resins, naphthalene skeleton-modified novolac epoxy resins, phenol aralkyl epoxy resins, naphthol aralkyl epoxy resins, dicyclopentadiene epoxy resins, biphenyl epoxy resins, alicyclic epoxy resins, polyol epoxy resins, phosphorus-containing epoxy resins, glycidyl amines, glycidyl esters, compounds in which the double bonds of butadiene or the like have been epoxidized, and compounds obtained by reacting hydroxyl group-containing silicone resins with epichlorohydrin.

[0062] The urethane-based resin is not particularly limited, but examples thereof include polyester-based urethane resins using polyester polyol as the polyol compound, polycarbonate-based urethane resins using polycarbonate polyol as the polyol compound, and polyether-based urethane resins using polyether polyol as the polyol compound.

[0063] The polyamide resin is not particularly limited, but examples thereof include aliphatic polyamides such as polyamide 4 (poly-α-pyrrolidone), polyamide 6 (polycaproamide), polyamide 11 (polyundecaneamide), polyamide 12 (polydodecanamide), polyamide 46 (polytetramethylene adipamide), polyamide 66 (polyhexamethylene adipamide), polyamide 610, and polyamide 612; semi-aromatic polyamides such as polyamide 6T (polyhexamethylene terephthalamide), polyamide 9T (polynonamethylene terephthalamide), and polyamide 6I (polyhexamethylene isophthalamide); wholly aromatic polyamides such as poly-p-phenylene terephthalamide, poly-p-benzamide, poly-p-amide hydrazide, and poly-p-phenylene terephthalamide-3,4-diphenyl ether terephthalamide; and copolymer polyamides containing these as constituent components.

[0064] The resin content is preferably 60 to 100 mass %, 65 to 95 mass %, or 70 to 90 mass % relative to the total amount of the binder layer 14. When the resin content is within the above range, the solvent resistance of the electrode 1 tends to be further improved.

[0065] The binder layer 14 may or may not contain other additives besides the resin. Examples of such additives include, but are not limited to, thickeners, crosslinking agents, and antioxidants. When the binder layer 14 contains other additives, the content of the other additives relative to the total amount of the binder layer 14 is, but is not limited to, for example, 0.5 to 10.0 mass %, or 1.0 to 5.0 mass %.

[0066] The thickness of binder layer 14 is preferably 10 μm or less, and is preferably 0.05 to 10 μm. When the thickness of binder layer 14 is within the above range, the solvent resistance of electrode 1 tends to be further improved, and the transparency of electrode 1 tends to be further improved.

[0067] 2. Electrode manufacturing method The method for producing electrode 1 of this embodiment includes a binder layer forming step of applying one or more resins selected from the group consisting of epoxy resins, urethane resins, and polyamide resins onto substrate 10 to form binder layer 14, and a conductive layer forming step of applying one or more liquids in which conductive polymers and / or metal nanowires are dispersed onto binder layer 14 to form conductive layer 12. The method for producing electrode 1 will be described in detail below.

[0068] 2.1. Binder layer formation process In the binder layer forming step, the method for applying the resin is not particularly limited, and examples thereof include spin coating, spray coating, dip coating, roll coating, inkjet coating, and manual application using a brush. In addition, to make it easier to apply the resin, the resin may be dissolved or dispersed in a solvent to obtain a mixed liquid, and the mixed liquid may be applied onto the substrate 10. The solvent is not particularly limited as long as it dissolves or disperses the resin, and examples thereof include alcohols such as 1-isopropanol and ethanol, and acetone.

[0069] 2.2. Conductive layer formation process In the conductive layer forming step, a liquid in which a conductive polymer is dispersed and a liquid in which metal nanowires are dispersed may be prepared and each may be applied to form the conductive layer 12. Alternatively, a liquid in which a conductive polymer and a metal nanowire are dispersed may be prepared and applied to form the conductive layer 12.

[0070] The liquid in which the conductive polymer is dispersed is not particularly limited, but examples thereof include water, propylene carbonate, nitromethane, alcohols such as methanol and ethanol, acetonitrile, etc. The liquid in which the metal nanowires are dispersed is not particularly limited, but examples thereof include water, alcohols such as methanol and ethanol, etc. The liquid in which the conductive polymer and / or metal nanowires are dispersed is also referred to as a dispersion medium hereinafter.

[0071] The method for applying the liquid in which the conductive polymer is dispersed and the liquid in which the metal nanowires are dispersed is not particularly limited, but examples thereof include spin coating, spray coating, dip coating, roll coating, and inkjet coating.

[0072] The conductive layer forming process may include a first conductive layer forming process in which a liquid in which a conductive polymer is dispersed is applied onto the binder layer 14 to form a first conductive layer 120A, a metal nanowire-containing layer forming process in which a liquid in which a metal nanowire is dispersed is applied onto the first conductive layer 120A to form a metal nanowire-containing layer 122, and a second conductive layer forming process in which a liquid in which a conductive polymer is dispersed is applied onto the metal nanowire-containing layer 122 to form a second conductive layer 120B.

[0073] The dispersion media used in the first conductor layer forming step, the second conductor layer forming step, and the metal nanowire-containing layer forming step may be the same or different. The conductive polymers used in the first conductor layer forming step and the second conductor layer forming step may be the same or different, but from the viewpoint of reducing the resistance of the electrode 1, it is preferable to use the same conductive polymer.

[0074] 3. Devices The device of this embodiment has a first electrode, a second electrode, and an electrochromic layer located between the first electrode and the second electrode, and the first electrode and / or the second electrode is electrode 1 described above.

[0075] Fig. 2 is a cross-sectional view showing an example of the configuration of a device. As shown in Fig. 2, device 2 may include a first electrode 1A, an electrochromic layer 22 on the first electrode 1A, and a second electrode 1B on the electrochromic layer 22. It is preferable that at least one of the first electrode 1A and the second electrode 1B is electrode 1, and it is more preferable that both are the above-mentioned electrode 1.

[0076] Hereinafter, each component of the device 2 other than the first electrode 1A and the second electrode 1B will be described in detail.

[0077] 3.1. Electrochromic Layer The electrochromic layer 22 includes an electrochromic composition. The electrochromic composition includes an electrochromic compound. An electrochromic compound is a compound that changes color when a voltage is applied.

[0078] The content of the electrochromic composition in the electrochromic layer 22 is preferably 80 to 100 mass %, or 90 to 100 mass %, and may consist essentially of the electrochromic composition, or may consist entirely of the electrochromic composition. When the content of the electrochromic composition is within the above range, the color development of the device tends to be further improved.

[0079] The thickness of the electrochromic layer is preferably 0.05 to 0.50 mm, more preferably 0.10 to 0.40 mm. When the thickness of the electrochromic layer is within the above range, the color development of the device tends to be further improved.

[0080] The device of this embodiment may include multiple electrochromic layers. For example, the device may include three electrochromic layers, and depending on the type of color to be expressed, one of the three electrochromic layers may be colored, two of the three electrochromic layers may be colored, or all three electrochromic layers may be colored.

[0081] Each component of the electrochromic composition will be described in detail below.

[0082] 3.1.1. Electrochromic Compounds The electrochromic composition of this embodiment contains an electrochromic compound. Examples of the electrochromic compound include viologens such as heptyl viologen, polypyrrole, tetrathiofulvalene, pasophenanthroline complexes, polypyrrole, polyacetylene, styryl compounds, rare earth phthalocyanines, anthraquinone, pyrazoline, and bipyridinium compounds such as 1,1'-diheptyl-4,4'-bipyridinium dibromide. The content of the electrochromic compound is preferably 1.0 to 20.0 mass%, 1.5 to 15.0 mass%, or 2.0 to 10.0 mass% relative to the total amount of the electrochromic composition. When the content of the electrochromic compound is within the above range, the color development of the electrochromic layer tends to be improved.

[0083] 3.1.2. Organic Solvents The electrochromic composition of this embodiment may contain an organic solvent. Examples of organic solvents include protic solvents, such as water and alcohol, which have hydrogen atoms bonded to oxygen or nitrogen and can donate protons, and aprotic solvents, such as N,N-dimethylformamide (DMF), acetone, and acetonitrile, which do not have such hydrogen atoms and therefore do not easily donate protons. Of these, aprotic solvents are preferred.

[0084] The aprotic solvent is not particularly limited, but examples thereof include DMF, acetone, acetonitrile, as well as hexane, benzene, toluene, 1,4-dioxane, chloroform, diethyl ether, N-methylpyrrolidone, dichloromethane, tetrahydrofuran, ethyl acetate, dimethyl sulfoxide (DMSO), and propylene carbonate.

[0085] The content of the organic solvent relative to the total amount of the electrochromic composition is not particularly limited, but is, for example, 0.1 to 10.0 mass %, 0.1 to 5.0 mass %, or 0.1 to 1.0 mass %.

[0086] 3.1.3. Electrolytes The electrochromic composition of the present embodiment may contain an electrolyte. The electrolyte is not particularly limited, but examples thereof include ion-dissociating salts that have good solubility in organic solvents.

[0087] The electrolyte is not particularly limited, but examples thereof include inorganic ion salts such as alkali metal salts and alkaline earth metal salts; quaternary ammonium salts; etc. Among these, alkali metal salts are preferred, and as the alkali metal salt, lithium salts are preferred.

[0088] More specifically, examples of the electrolyte include alkali metal salts of Li, Na, and K, such as LiClO4, LiSCN, LiBF4, LiAsF6, LiCF3SO3, LiPF6, LiI, LiBr, Li(CF3SO2)2N, NaI, NaSCN, NaClO4, NaBF4, NaAsF6, KSCN, and KCl; quaternary ammonium salts, such as (CH3)4NBF4, (C2H5)4NBF4, (n-C4H9)4NBF4, (n-C4H9)4NPF6, (C2H5)4NBr, (C2H5)4NClO4, and (n-C4H9)4NClO4; and imidazolium compounds, such as 1-butyl-3-methylimidazolium tetrafluoroborate.

[0089] The content of the electrolyte is preferably 50.0 to 90.0 mass %, 60.0 to 87.5 mass %, or 65.0 to 85.0 mass % relative to the total amount of the electrochromic composition. When the content of the electrolyte is within the above range, the conductivity of the electrochromic composition is improved, and the electrochromic composition tends to be more easily colored.

[0090] 3.1.4. Redox Compounds The electrochromic composition of the present embodiment may contain an oxidation-reduction compound. The oxidation-reduction compound is a compound that promotes and stabilizes the reaction when an electrochromic compound that changes color upon application of a voltage is oxidized or reduced to change color. The oxidation-reduction compound is also a compound that promotes and stabilizes the reaction when the electrochromic compound is oxidized or reduced to lose its color. By including an oxidation-reduction compound in the electrochromic composition of the present embodiment, the oxidation-reduction reaction for changing color in the electrochromic compound is facilitated, and color change tends to be achieved at a lower voltage, which is preferable.

[0091] The redox compound is not particularly limited, but examples thereof include oligothiophenes; phenazine compounds such as 5,10-dihydro-5,10-dimethylphenazine and 5,10-dihydro-5,10-diisopropylphenazine; pyrazoline compounds such as 1-phenyl-2-pyrazoline; ethanedione compounds; tetrazolium salts; formazan compounds; phenoxazine compounds; acridine compounds; diphenylethanedione compounds; metallocene compounds such as ferrocene, tetra-t-butylferrocene, titanocene, and cobaltocene; phenylenediamine compounds such as N,N',N,N'-tetramethyl-p-phenylenediamine; and phenothiazine compounds. Among these, metallocene compounds are preferred from the viewpoint of achieving color development at lower voltages, and ferrocene compounds having Fe as the central metal are more preferred.

[0092] The ferrocene compound has a ferrocene skeleton, and the two cyclopentadienyl rings may each independently have 1 to 5 monovalent alkyl groups having 1 to 5 carbon atoms. The ferrocene compound is not particularly limited, but examples thereof include ferrocene, methylferrocene, 1,1'-dimethylferrocene, decamethylferrocene, ethylferrocene, propylferrocene, butylferrocene, and pentylferrocene.

[0093] The content of the redox compound is preferably 0.5 to 10.0 mass %, 0.7 to 7.5 mass %, or 1.0 to 5.0 mass %, relative to the total amount of the electrochromic composition. When the content of the redox compound is within the above range, the electrochromic composition tends to be able to exhibit color at a lower voltage.

[0094] The ratio of the content of the redox compound to the content of the electrochromic compound (content of the redox compound / content of the electrochromic compound) is preferably 0.10 to 1.00, 0.15 to 0.75, or 0.20 to 0.50. When the ratio is within the above range, the color of the electrochromic composition tends to be achieved at a lower voltage.

[0095] 3.1.5. Gelling Agents The electrochromic composition of the present embodiment may contain a gelling agent. By containing a gelling agent, the electrochromic composition is less likely to leak from the device described below, and the composition tends to be easier to apply to the device.

[0096] The gelling agent is not particularly limited, but examples of the polymer include, but are not limited to, polyvinyl butyral (PVB), polyacrylonitrile, carboxymethyl cellulose, pullulan-based polymers, polyvinyl chloride, polyethylene oxide, polypropylene oxide, polyurethane, polyacrylate, polymethacrylate, polyamide, polyacrylamide, polyester, and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP).

[0097] The content of the gelling agent is preferably 5.0 to 30.0 mass%, 7.5 to 27.5 mass%, or 10.0 to 25.0 mass% relative to the total amount of the electrochromic composition. When the content of the gelling agent is within the above range, the electrochromic composition tends to be easily applied to devices.

[0098] 3.1.6. Other additives The electrochromic composition of this embodiment may or may not contain other additives. Examples of other additives include a pH adjuster, a plasticizer, a leveling agent, a dispersant, a surfactant, and an antioxidant. When the electrochromic composition of this embodiment contains other additives, the content of the other additives is not particularly limited, but is, for example, 0.1 to 10.0 mass% relative to the total amount of the electrochromic composition.

[0099] 3.2. Other Layers The device 2 of this embodiment may or may not have layers other than the first electrode 1A, the second electrode 1B, and the electrochromic layer 22. The other layers are not particularly limited, but examples thereof include an adhesive layer for improving adhesion between the first electrode 1A and the second electrode 1B and the electrochromic layer 22. [Example]

[0100] The present invention will be described in more detail below using examples and comparative examples. The present invention is not limited to the following examples. The experiments in the examples and comparative examples were carried out at room temperature (25°C) under 1 atmosphere unless otherwise specified.

[0101] 1. Device Fabrication [Example 1] An acrylic substrate (manufactured by Osaka Organic Chemical Industry Co., Ltd., product name SUAVE-15F100) was cut into a size of 2.5 cm x 2.5 cm. Onto the cut acrylic substrate, 1 mL of a mixture obtained by mixing a polyamide copolymer (manufactured by Toagosei Co., Ltd., product name Aronmighty FS175SV) and 1-propanol in a volume ratio of 1:1 was applied using a spin coater and allowed to dry. This formed a binder layer.

[0102] Next, a PEDOT / PSS-water dispersion (Sigma-Aldrich, catalog number 739324-100G) was prepared by dispersing a thiophene-based polymer, polyethylenedioxythiophene (PEDOT / PSS), with added polystyrene sulfonic acid (PSS) in water. This dispersion was then mixed with distilled water and Surflon s243 (AGC, product name) in a mass ratio of PEDOT / PSS:water:Surflon s243 = 100:100:1. 1 mL of the resulting mixture was then applied to the binder layer using a spin coater and dried. This formed the first conductive layer.

[0103] Then, 1 mL of AgNW-IPA dispersion (manufactured by Seiko PMC Corporation, silver nanowire concentration: 0.5 mass%, product name: T-AG224) prepared by dispersing silver nanowires (AgNWs) in 1-propanol was applied to the first conductive layer using a spin coater and dried. This application and drying process was repeated five times in total. This resulted in the formation of a metal nanowire-containing layer. The AgNWs in the AgNW-IPA dispersion had a length of approximately 10 μm and a diameter of approximately 20-25 nm.

[0104] Finally, 1 mL of the same mixture used to form the first conductive layer was applied to the metal nanowire-containing layer using a spin coater and dried. This formed a second conductive layer. In this way, the electrode of Example 1 was obtained.

[0105] Spin coating was performed as follows: the rotation speed was first increased to 500 rpm and maintained at 500 rpm for 10 seconds, then increased to 1500 rpm and maintained at 1500 rpm for another 10 seconds, and drying was performed at 120°C for 1 minute.

[0106] [Comparative Example 1] An electrode of Comparative Example 1 was obtained by forming a metal nanowire-containing layer and a second conductive layer in the same manner as in Example 1, except that a binder layer was not formed and the first conductive layer was formed directly on the acrylic substrate.

[0107] Comparative Example 2 An electrode of Comparative Example 2 was obtained in the same manner as in Example 1, except that the first conductive layer and the second conductive layer were not formed and the metal nanowire-containing layer was formed directly on the binder layer.

[0108] [Resistance measurement] For each electrode, the resistance was measured when the elongation rate was 0% or 60%, and the resistance per unit length was calculated. A Fluke 177 True RMS Multimeter was used for the measurement. The calculation results are shown in Table 1. The resistance per unit length and the elongation rate can be calculated using the following formulas. Resistance per unit length (Ω / cm) = measured resistance value (Ω) / distance between probes during measurement (cm) Elongation rate (%) = (lateral length of electrode in stretched state - original lateral length of electrode) / original lateral length of electrode × 100

[0109] Next, the resistance of each electrode was measured and the resistance per unit length was calculated while the electrode was stretched laterally. The elongation was measured at the point when the resistance per unit length reached 60 MΩ / cm. The measurement results are shown in Table 1. In Example 1, the resistance per unit length at an elongation rate of 0% was 200 Ω / cm, and the resistance per unit length at an elongation rate of 60% was 250 Ω / cm.

[0110] [Table 1]

[0111] 2. Evaluation 2.1.Transparency The transparency of the electrode in each example in the thickness direction was evaluated by the transmittance of visible light at a wavelength of 555 nm using an ultraviolet-visible spectrophotometer (Shimadzu Corporation, UV-1900i). Shown in Table 3.

[0112] 2.2.Solvent resistance First, the resistance value per unit length of the electrode of each example was measured. Next, 40 μL of DMF or acetone was dropped onto the electrode of each example and left for 30 minutes. Thereafter, the DMF or acetone on the surface was wiped off, and the resistance value per unit length was measured. The measurement results are shown in Table 3. In Comparative Example 1, the resistance value increased significantly after the dropping of DMF or acetone. This is thought to be because Comparative Example 1 did not have a binder layer and had low solvent resistance.

[0113] 2.3.Durability to deformation For each electrode, the elongation rate at which the resistance per unit length reached 60 MΩ / cm was evaluated based on the following criteria. The evaluation results are shown in Table 3. By using an electrode rated A in a device, the device will have sufficiently low electrode resistance even when used in an environment where it will be significantly deformed. Such a device can be said to be excellent in energy conservation. [Evaluation criteria] A: The elongation rate is 250% or more when the resistance per unit length reaches 60MΩ / cm. B: The elongation rate at which the resistance per unit length reaches 60 MΩ / cm is 200% or more and less than 250%. C: The elongation rate is less than 200% when the resistance per unit length reaches 60 MΩ / cm.

[0114] Furthermore, the resistance per unit length of each electrode example at an elongation rate of 60% was evaluated based on the following evaluation criteria. The evaluation results are shown in Table 3. By using an electrode rated A in a device, the device will have sufficiently low electrode resistance even when used in an environment where it will be significantly deformed. Such a device can be said to be excellent in energy conservation. [Evaluation criteria] A: The resistance per unit length at an elongation rate of 60% is 300 Ω / cm or less. B: The resistance per unit length at an elongation rate of 60% is more than 300 Ω / cm and 500 Ω / cm or less. C: Resistance per unit length at an elongation rate of 60% is more than 500 Ω / cm.

[0115] [Table 2] [Explanation of symbols]

[0116] 1...electrode, 1A...first electrode, 1B...second electrode, 10...substrate, 12...conductive layer, 120A...first conductive layer, 120B...second conductive layer, 122...metal nanowire-containing layer, 14...binder layer, 2...device, 22...electrochromic layer

Claims

1. A substrate, a binder layer, and a conductive layer are provided at least in this order; the conductive layer includes metal nanowires and a conductive polymer; electrode.

2. the metal nanowires include silver nanowires; 10. The electrode of claim 1.

3. The conductive polymer includes a thiophene-based polymer.

10. The electrode of claim 1.

4. the conductive layer includes a first conductive layer containing the conductive polymer, a second conductive layer containing the conductive polymer, and a metal nanowire-containing layer located between the first conductive layer and the second conductive layer and containing the metal nanowires; 10. The electrode of claim 1.

5. the binder layer contains one or more resins selected from the group consisting of epoxy-based resins, urethane-based resins, and polyamide-based resins; 10. The electrode of claim 1.

6. The thickness of the binder layer is 10 μm or less.

10. The electrode of claim 1.

7. The resistance per unit length of the electrode when the elongation rate is 0% is 250 Ω / cm or less.

10. The electrode of claim 1.

8. The resistance per unit length of the electrode when the elongation rate is 60% is 1000 Ω / cm or less.

10. The electrode of claim 1.

9. When the electrode is stretched and the resistance of the electrode becomes 60 MΩ / cm or more, the elongation rate of the electrode is 250% or more.

10. The electrode of claim 1.

10. The visible light transmittance of the electrode when no voltage is applied is 10% or more.

10. The electrode of claim 1.

11. The electrode according to any one of claims 1 to 10, for use in an electrochromic device.

12. A first electrode; A second electrode; an electrochromic layer located between the first electrode and the second electrode; The first electrode and / or the second electrode is an electrode according to any one of claims 1 to 10. device.

13. a binder layer forming step of applying one or more resins selected from the group consisting of epoxy resins, urethane resins, and polyamide resins onto a substrate to form a binder layer; and a conductive layer forming step of applying one or more liquids in which a conductive polymer and / or metal nanowires are dispersed onto the binder layer to form a conductive layer. Electrode manufacturing method.

14. The conductive layer forming step a first conductive layer forming step of applying a liquid in which the conductive polymer is dispersed onto the binder layer to form a first conductive layer; a metal nanowire-containing layer forming step of applying a liquid in which the metal nanowires are dispersed onto the first conductive layer to form a metal nanowire-containing layer; a second conductive layer forming step of applying a liquid in which the conductive polymer is dispersed onto the metal nanowire-containing layer to form a second conductive layer; having The method for manufacturing the electrode according to claim 13.

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