Electrode

Abstract

An electrode (1) is provided with a base film (2), a first underlayer (3), a second underlayer (4), and a conductive carbon layer (5) in this order toward one side in the thickness direction, the first underlayer (3) being a metal layer or a semimetal layer, the second underlayer (4) being a metal layer, and the specific resistance of the first underlayer (3) being 10 times or more of the specific resistance of the second underlayer (4).

Description

TECHNICAL FIELD

[0001] The present application relates to an electrode. BACKGROUND

[0002] As an electrode (working electrode) used in an electrochemical measurement method, a carbon electrode has been known.

[0003] As such a carbon electrode, for example, an electrode provided with a film substrate, a titanium thin film, and a carbon thin film in this order in the thickness direction has been proposed (for example, see Patent Literature 1 below).

[0004] In addition, as such a carbon electrode, for example, an electrode provided with a film substrate, a silicon oxide thin film, a titanium thin film, and a carbon thin film in this order in the thickness direction has been proposed (for example, see Patent Literature 2 below).

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: International Publication No. 2019 / 117112

[0008] Patent Literature 2: International Publication No. 2022 / 019299 SUMMARY

[0009] PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] On the other hand, in the electrode used in the electrochemical measurement, in order to improve the measurement sensitivity, it is necessary to reduce the absolute value of the resistance, and in addition, in order to ensure the measurement accuracy, high reliability is required.

[0011] In the carbon electrode of Patent Literature 1, the absolute value of the resistance can be reduced by the titanium thin film, but on the other hand, the absolute value of the resistance sometimes changes over time due to outgassing from the film substrate, and higher reliability is desired.

[0012] In the electrode of Patent Literature 2, outgassing from the film substrate is suppressed by the silicon oxide thin film, and high reliability is ensured, but on the other hand, the titanium thin film is oxidized at the time of film formation due to the silicon oxide thin film, and thus the absolute value of the resistance of the entire electrode sometimes becomes high, and further reduction of the absolute value of the resistance of the entire electrode is desired.

[0013] The present application provides an electrode having a low absolute value of the resistance, and in addition, high reliability.

[0014] MEANS FOR SOLVING THE PROBLEMS

[0015] The present application [1] includes an electrode which has, in order toward a thickness direction side, a base material film, a first base layer, a second base layer, and a conductive carbon layer, the first base layer is a metal layer or a semi-metal layer, the second base layer is a metal layer, and the specific resistance of the first base layer is 10 times or more of the specific resistance of the second base layer.

[0016] The present application [2] includes the electrode described in [1], wherein the conductive carbon layer has sp 2 bond and sp 3 bond.

[0017] The present application [3] includes the electrode described in [1] or [2], wherein the second base layer contains titanium.

[0018] The present application [4] includes the electrode described in any one of [1] to [3], wherein the specific resistance of the second base layer is 3.0 x 10 -4 Ω·cm or less.

[0019] The present application [5] includes the electrode described in any one of [1] to [4], wherein the first base layer is a semi-metal layer and contains silicon.

[0020] The present application [6] includes the electrode described in any one of [1] to [5], wherein the thickness of the first base layer is 3 nm or more.

[0021] The present application [7] includes the electrode described in any one of [1] to [6], which is an electrode for electrochemical measurement.

[0022] Effects of Invention

[0023] The electrode of the present application has a low absolute value of resistance and also has high reliability. BRIEF DESCRIPTION OF DRAWINGS

[0024] [ Figure 1 ] Figure 1 is a cross-sectional view of an embodiment of the electrode of the present application. DETAILED DESCRIPTION

[0025] <Embodiment>

[0026] Reference Figure 1 An embodiment of the electrode film of the present application is described. Figure 1 In the present application, the up-and-down direction on a paper surface is the up-and-down direction (thickness direction, first direction), the upper side on the paper surface is the upper side (thickness direction side, first direction side), and the lower side on the paper surface is the lower side (thickness direction other side, first direction other side). In addition, the left-and-right direction on the paper surface and the depth direction are surface directions orthogonal to the up-and-down direction. Specifically, the directions are indicated by the arrows in the respective drawings.

[0027] As Figure 1As shown, the electrode 1 has a prescribed thickness. The electrode 1 has a film shape (including a sheet shape). The electrode 1 has, in order toward a thickness direction side, a base material film 2, a first base layer 3, a second base layer 4, and a conductive carbon layer 5. Specifically, the electrode 1 has only the base material film 2, the first base layer 3, the second base layer 4, and the conductive carbon layer 5.

[0028] [Base material film]

[0029] The base material film 2 is a base material that supports the first base layer 3, the second base layer 4, and the conductive carbon layer 5. The base material film 2 is the lowermost layer of the electrode 1 and has a film shape.

[0030] The base material film 2 has a prescribed thickness. As a material of the base material film 2, for example, an organic material can be cited.

[0031] As the organic material, for example, a resin material can be cited.

[0032] As the resin material, for example, a polyester resin, an acetate resin, a polyether sulfone resin, a polycarbonate resin, a polyamide resin, a polyimide resin, a polyolefin resin, an acrylic resin, a polyvinyl chloride resin, a polyvinylidene chloride resin, a polystyrene resin, a polyvinyl alcohol resin, a polyarylate resin, and a polyphenylene sulfide resin can be cited, and preferably, a polyester resin can be cited.

[0033] As the polyester resin, for example, a polyethylene terephthalate and a polyethylene naphthalate can be cited, and preferably, a polyethylene terephthalate can be cited.

[0034] The material of the base material film 2 can be used alone or in combination.

[0035] The thickness of the base material film 2 is not particularly limited. The thickness of the base material film 2 is, for example, 2 μm or more, preferably 20 μm or more, more preferably 50 μm or more, and further preferably 100 μm or more, and, for example, 1000 μm or less, preferably 500 μm or less, and more preferably 300 μm or less.

[0036] [First base layer]

[0037] The first base layer 3 is a layer that suppresses the influence of the base material film 2 on the second base layer 4. The first base layer 3 is disposed on one face of the base material film 2 in the thickness direction. Specifically, the first base layer 3 is in contact with the entire face of one face of the base material film 2 in the thickness direction. The first base layer 3 has a prescribed thickness.

[0038] As the first base layer 3, a metal layer or a semi-metal layer can be cited. The first base layer 3 is preferably not a metal oxide layer and a semi-metal oxide layer.

[0039] In the case where the first base layer 3 is not a metal oxide layer and a semi-metal oxide layer, when the second base layer 4 described later is formed, oxidation can be suppressed, and the absolute value of the resistance of the electrode 1 can be reduced.

[0040] The metal layer as the first base layer 3 is made of a metal.

[0041] As the metal as the material of the first base layer 3, for example, platinum, tin, tantalum, chromium, palladium, niobium, rhenium, strontium, vanadium, ytterbium, gallium, hafnium, zirconium, titanium, germanium, scandium, lutetium, yttrium, lanthanum, neodymium, thulium, praseodymium, holmium, cerium, erbium, europium, dysprosium, samarium, radium, bismuth, terbium, gadolinium, manganese, and alloys thereof can be given.

[0042] The metal as the material of the first base layer 3 can be used alone or in combination.

[0043] The semi-metal layer as the first base layer 3 is made of a semi-metal. The semi-metal is not limited.

[0044] As the semi-metal as the material of the first base layer 3, for example, silicon can be given.

[0045] The semi-metal as the material of the first base layer 3 can be used alone or in combination.

[0046] The first base layer 3 is preferably a semi-metal layer.

[0047] The specific resistance (measured value of a thin film) of the first base layer 3 is, for example, 10 x 10 -6 Ω·cm or more, preferably 4.0 x 10 -5 Ω·cm or more, more preferably 10 x 10 -5 Ω·cm or more, further preferably 5.0 x 10 -4 Ω·cm or more, particularly preferably 10 x 10 -4 Ω·cm or more, and, for example, 1.0 x 10 3 Ω·cm or less.

[0048] Note that the specific resistance (measured value of a thin film) of the first base layer 3 can be obtained by multiplying the absolute value of the resistance (Ω / □) of the single layer of the first base layer 3 (in a state where the first base layer 3 is formed on the base material film 2) by the thickness of the first base layer 3. Specifically, the measurement is performed as described in the examples described later.

[0049] When the specific resistance of the first base layer 3 is the above lower limit or more, even if the first base layer 3 is oxidized by the outgassing from the base material film 2, the influence on the absolute value of the resistance of the electrode 1 is small, and thus the absolute value of the resistance of the electrode 1 can be reduced.

[0050] The thickness of the first base layer 3 is not particularly limited. The thickness of the first base layer 3 is, for example, 1 nm or more, preferably 3 nm or more, and, on the other hand, for example, 50 nm or less, preferably 25 nm or less, more preferably 10 nm or less.

[0051] When the thickness of the first base layer 3 is the above lower limit or more, the first base layer 3 is excellent in uniformity in the planar direction. In addition, the permeation of the outgas from the base material film 2 can be suppressed, the temporal change in the absolute value of the resistance of the second base layer 4 described later can be suppressed, and the reliability of the electrode 1 is excellent.

[0052] <Second Base Layer>

[0053] The second base layer 4 is disposed on one face in the thickness direction of the first base layer 3. Specifically, the second base layer 4 is in contact with the entire face of one face in the thickness direction of the first base layer 3. The second base layer 4 has a thickness.

[0054] As the second base layer 4, a metal layer can be given.

[0055] The metal layer as the second base layer 4 is made of a metal.

[0056] As the metal as the material of the second base layer 4, a metal that can form a carbide with carbon of the conductive carbon layer 5 described later is preferable.

[0057] As the metal as the material of the second base layer 4, from the viewpoint of ensuring the chemical stability of the conductive carbon layer 5, for example, silver, copper, gold, aluminum, magnesium, rhodium, tungsten, iridium, cobalt, nickel, ruthenium, indium, osmium, iron, platinum, tin, tantalum, chromium, palladium, niobium, rhenium, strontium, vanadium, ytterbium, gallium, hafnium, zirconium, titanium, germanium, scandium, lutetium, yttrium, lanthanum, neodymium, thulium, praseodymium, holmium, cerium, erbium, europium, dysprosium, samarium, radium, bismuth, terbium, gadolinium, molybdenum, and manganese can be given, and titanium and niobium are preferable.

[0058] The metal as the material of the second base layer 4 can be used alone or in combination.

[0059] The specific resistance (measured value of a thin film) of the second base layer 4 is, for example, 10 x 10 -4 Ω·cm or less, preferably 5.0 x 10 -4 Ω·cm or less, more preferably 3.0 x 10 -4 Ω·cm or less, further preferably 2.0 x 10 -4 Ω·cm or less, particularly preferably 1.5 x 10 -4 Ω·cm or less, and, on the other hand, for example, 1.0 x 10 -7 Ω·cm or more.

[0060] Note that the specific resistance of the second base layer 4 (measured value of the thin film) can be calculated by multiplying the resistance absolute value (Ω / □) of the electrode (the electrode having the substrate film 2, the second base layer 4, and the conductive carbon layer 5) by the thickness of the second base layer 4. As with the first base layer 3, it can also be the resistance absolute value (Ω / □) when the second base layer 4 is a single layer, but the specific resistance of the second base layer 4 is sufficiently lower than the specific resistance of the conductive carbon layer 5, so the influence of the resistance absolute value (Ω / □) of the conductive carbon layer 5 on the electrode can be ignored, and thus the above-mentioned resistance absolute value (Ω / □) of the electrode can be used. Specifically, it is measured as described in the examples described later.

[0061] When the specific resistance of the second base layer 4 is the above upper limit or less, the resistance absolute value of the electrode 1 can be reduced.

[0062] The thickness of the second base layer 4 is not particularly limited. The thickness of the second base layer 4 is, for example, 1 nm or more, preferably 3 nm or more, and more preferably 5 nm or more, and, for example, 50 nm or less, and preferably 30 nm or less.

[0063] When the thickness of the second base layer 4 is the above lower limit or more, the second base layer 4 is excellent in uniformity in the planar direction.

[0064] On the other hand, when the thickness of the second base layer 4 is the above upper limit or less, the conductivity of the second base layer 4 is also excellent.

[0065] The specific resistance of the first base layer 3 is 10 times or more, preferably 100 times or more, and more preferably 1 x 10 3 times or more, and further preferably 1 x 10 4 times or more, and, for example, 1 x 10 20 times or less.

[0066] When the specific resistance of the first base layer 3 is the above lower limit times or more than the specific resistance of the second base layer 4, even if the first base layer 3 is oxidized by the outgassing oxygen from the substrate film 2, the influence on the resistance absolute value of the entire electrode 1 can be suppressed, and the resistance change can be suppressed.

[0067] <Conductive Carbon Layer>

[0068] The conductive carbon layer 5 has electrode properties and is a layer that functions as an electrode. The conductive carbon layer 5 is disposed on one face in the thickness direction of the second base layer 4. Specifically, the conductive carbon layer 5 is in contact with the entire face of one face in the thickness direction of the second base layer 4. The conductive carbon layer 5 is the uppermost layer of the electrode 1 and has a prescribed thickness.

[0069] The material of the conductive carbon layer 5 is carbon, and preferably has sp 2 bonds and sp3 The carbon having sp 2 bond and sp 3 The carbon having sp 3 The number of atoms bonded to sp 3 The number of atoms bonded to sp 2 The ratio of the sum of the number of atoms bonded to sp 3 / sp 3 +sp 2 ) is not particularly limited. The ratio (sp 3 / sp 3 +sp 2 ) is, for example, 0.1 or more, preferably 0.2 or more, and, for example, 0.9 or less, preferably 0.5 or less. The ratio (sp 3 / sp 3 +sp 2 ) is calculated based on the peak intensity of sp 2 bond and the peak intensity of sp 3 bond in a spectrum obtained by measuring one face in the thickness direction of the conductive carbon layer 5 by X-ray photoelectron spectroscopy.

[0070] The thickness of the conductive carbon layer 5 is not particularly limited. The thickness of the conductive carbon layer 5 is, for example, 5 nm or more, preferably 8 nm or more, and, for example, 200 nm or less, preferably 100 nm or less, more preferably 50 nm or less. The thickness of the conductive carbon layer 5 can be calculated by measuring the X-ray reflectance.

[0071] In addition, it is preferable that a carbide layer (not shown) be formed at the interface between the conductive carbon layer 5 and the second base layer 4. The carbide layer is formed from a compound, i.e., a carbide, formed from the metal that is the second base layer 4 and the carbon of the conductive carbon layer 5. By the carbide layer, the adhesion between the conductive carbon layer 5 and the second base layer 4 is improved. In this case, the electrode 1 has, in order toward the thickness direction side, the substrate film 2, the first base layer 3, the second base layer 4, the carbide layer not shown, and the conductive carbon layer 5.

[0072] Note that the conductive carbon layer 5 can contain other elements in addition to carbon.

[0073] <Method for manufacturing electrode>

[0074] Next, the method for manufacturing the electrode 1 will be described. First, the substrate film 2 is prepared. Next, the first base layer 3, the second base layer 4, and the conductive carbon layer 5 are formed in order toward the thickness direction side of the substrate film 2.

[0075] As a method of forming the first base layer 3, for example, a dry method and a wet method can be given. A dry method is preferable. As the dry method, for example, a PVD method (physical vapor deposition method) and a CVD method (chemical vapor deposition method) can be given. As the dry method, a PVD method is preferable. As the PVD method, for example, a sputtering method, a vacuum evaporation method, a laser evaporation method, and an ion plating method (arc evaporation method) can be given. As the PVD method, a sputtering method is preferable. The sputtering method is not particularly limited. As the sputtering method, for example, an unbalanced magnetron sputtering method (UBM sputtering method), a high power impulse sputtering method, an electron cyclotron resonance sputtering method, an RF sputtering method, a DC sputtering method (DC magnetron sputtering method), a DC pulse sputtering method, and an ion beam sputtering method can be given.

[0076] In addition, in the sputtering method, for example, a sputtering gas containing an inactive gas and a target formed of an inorganic substance are used. Further, the sputtering gas preferably does not contain oxygen.

[0077] When the sputtering gas does not contain oxygen, oxidation of the metal or semimetal as the material of the first base layer 3 can be suppressed.

[0078] As the inactive gas, for example, argon can be given.

[0079] As the material of the first base layer 3, for example, the above-mentioned metal or semimetal can be given, and a semimetal is preferable.

[0080] As a method of forming the second base layer 4, the same method as the above-mentioned method of forming the first base layer 3 can be given.

[0081] In addition, as the material of the second base layer 4, from the viewpoint of ensuring chemical stability of the electrically conductive carbon layer 5, for example, the above-mentioned metal can be given, and titanium and niobium are preferable.

[0082] As a method of forming the electrically conductive carbon layer 5, the same method as the above-mentioned method of forming the first base layer 3 can be given. In the case where the electrically conductive carbon layer 5 is formed by a sputtering method, for example, carbon can be used, and sintered carbon is preferable as the target material.

[0083] Thus, the electrode 1 is obtained.

[0084] The total thickness of the obtained electrode 1 is, for example, 2 μm or more, preferably 20 μm or more, more preferably 50 μm or more, and further preferably 100 μm or more, and is, for example, 1000 μm or less, preferably 500 μm or less, and more preferably 300 μm or less.

[0085] The absolute value of the resistance of the electrode 1 is, for example, 1.0 x 10 3 Ω / □ or less, preferably 5.0 x 10 2 Ω / □ or less, and more preferably 3.0 x 10 2Ω / □ or less. The absolute value of the resistance can be measured by the method described later.

[0086] The rate of change of the absolute value of the resistance (reliability) of the electrode 1 is, for example, 50% or less, preferably 10% or less, more preferably 5% or less, further preferably 3% or less, and particularly preferably 1% or less. The rate of change of the absolute value of the resistance (reliability) can be measured by the method described later.

[0087] <Effects>

[0088] The electrode 1 has, in order from the side in the thickness direction, the substrate film 2, the first base layer 3, the second base layer 4, and the conductive carbon layer 5, the first base layer 3 is a metal layer or a semi-metal layer, the second base layer 4 is a metal layer, and the specific resistance of the first base layer 3 is 10 times or more the specific resistance of the second base layer 4. Thus, the absolute value of the resistance is low and the reliability is high.

[0089] More specifically, the first base layer 3 is provided on the side in the thickness direction of the substrate film 2. Thus, the permeation of the gas from the substrate film 2 can be suppressed, and the oxidation of the second base layer 4 can be suppressed.

[0090] Even if the first base layer 3 is oxidized by the gas from the substrate film 2 and the absolute value of the resistance of the first base layer 3 increases, since the specific resistance of the first base layer 3 is 10 times or more the specific resistance of the second base layer 4, the influence on the absolute value of the resistance of the entire electrode 1 can be suppressed, and the absolute value of the resistance of the electrode 1 can be reduced.

[0091] In addition, the permeation of the gas from the substrate film 2 can be suppressed by the first base layer 3, and the oxidation of the second base layer 4 can be suppressed. Thus, the reliability of the electrode 1 is excellent.

[0092] Further, since the first base layer 3 is a metal or a semi-metal, the oxidation of the second base layer 4 can be suppressed, and the absolute value of the resistance of the electrode 1 can be reduced.

[0093] <Use>

[0094] The use of the electrode 1 is not particularly limited. As the use of the electrode 1, for example, an electrode for electrochemical measurement can be given. Specifically, the electrode 1 can be provided in an electrochemical measurement system including the electrode 1 as a working electrode.

[0095] Example

[0096] The following Examples and Comparative Examples further specifically illustrate the present application. Note that the present application is not limited to any of the Examples and Comparative Examples. In addition, the specific numerical values of the compounding ratio (content ratio), physical property values, parameters, etc. used in the following description can be replaced with the upper limit (numerical value defined as "below", "less than") or lower limit (numerical value defined as "above", "more than") of the compounding ratio (content ratio), physical property values, parameters, etc. corresponding thereto, which are described in the above "DETAILED DESCRIPTION".

[0097] Example 1

[0098] A substrate film 2 of 188 μm in thickness formed of polyethylene terephthalate was prepared.

[0099] Next, a semimetal layer (first base layer 3) formed of silicon was formed on one face in the thickness direction of the substrate film 2 by a magnetron sputtering method. The conditions of the magnetron sputtering method were as described below.

[0100] Target material: silicon

[0101] Target power: 1.1 W / cm 2

[0102] Sputtering gas: argon

[0103] Pressure in sputtering chamber: 0.2 Pa

[0104] The thickness of the semimetal layer was 5 nm.

[0105] Next, a metal layer (second base layer 4) formed of titanium was formed on one face in the thickness direction of the semimetal layer (first base layer 3) by a magnetron sputtering method. The conditions of the magnetron sputtering method were as described below.

[0106] Target material: titanium

[0107] Target power: 0.4 W / cm 2

[0108] Sputtering gas: argon

[0109] Pressure in sputtering chamber: 0.2 Pa

[0110] The thickness of the second base layer 4 was 8 nm.

[0111] Next, a conductive carbon layer 5 was formed on one face in the thickness direction of the second base layer 4 by a DC pulse sputtering method. The conditions of the DC pulse sputtering method were as described below.

[0112] Target material: sintered carbon

[0113] Target power: 3.0 W / cm 2

[0114] Sputtering gas: argon

[0115] Pressure in sputtering chamber: 0.2 Pa

[0116] The thickness of the conductive carbon layer 5 was 10 nm.

[0117] Thus, an electrode 1 was produced which had, toward one side in the thickness direction, the substrate film 2, the semi-metal layer (first base layer 3), the second base layer 4, and the conductive carbon layer 5 in that order.

[0118] Example 2

[0119] Example 2 was produced in the same manner as the electrode of Example 1, except that the following. The thickness of the semi-metal layer was set to 3 nm, and, as the second base layer 4, a metal layer formed from niobium was formed on one face of the semi-metal layer (first base layer 3) in the thickness direction, with a thickness of 15 nm. Note that the conditions for the magnetron sputtering method at the time of forming the second base layer 4 were as follows.

[0120] Target material: niobium

[0121] Target power: 0.4 W / cm 2

[0122] Sputtering gas: argon

[0123] Pressure in sputtering chamber: 0.2 Pa

[0124] Example 3 and Example 4

[0125] Example 3 and Example 4 were produced in the same manner as the electrode of Example 2, except that the thickness of the metal layer formed from niobium (second base layer 4) was changed as shown in Table 1.

[0126] Comparative Example 1

[0127] Example 1 was processed in the same manner, except that the first base layer 3 was not formed. That is, the electrode 1 had, toward one side in the thickness direction, the substrate film 2, the second base layer 4, and the conductive carbon layer 5 in that order.

[0128] Comparative Example 2

[0129] Example 1 was processed in the same manner, except that a semi-metal oxide layer was formed instead of the semi-metal layer. That is, a semi-metal oxide layer formed from silicon oxide was formed on one face of the substrate film 2 in the thickness direction by a magnetron sputtering method. The conditions for the magnetron sputtering method were as follows.

[0130] Target material: silicon

[0131] Target power: 3.3 W / cm 2

[0132] Sputtering gas: argon and oxygen (flow rate ratio: 9:1)

[0133] Pressure of sputtering: 0.2 Pa

[0134] The thickness of the semimetal oxide layer was 5 nm.

[0135] Thus, an electrode 1 having the substrate film 2, the semimetal oxide layer, the second base layer 4, and the conductive carbon layer 5 in this order toward one side in the thickness direction was manufactured.

[0136] Comparative Examples 3 to 5

[0137] The first base layer 3 was not formed, and otherwise, the same processes as in Examples 2 to 4 were performed. That is, the electrode 1 of Comparative Examples 3 to 5 had the substrate film 2, the second base layer 4, and the conductive carbon layer 5 in this order toward one side in the thickness direction.

[0138] [Specific resistance of the first base layer (measured value of thin film)]

[0139] A sample 1 was prepared in which a semimetal layer (first base layer 3) formed of silicon was formed on one face in the thickness direction of a substrate film 2 formed of polyethylene terephthalate having a thickness of 188 μm using a magnetron sputtering method. The conditions of the magnetron sputtering method at the time of forming the first base layer 3 were set to be the same as in Example 1. In addition, the thickness of the semimetal layer was set to be 5 nm.

[0140] The absolute value of the resistance of the prepared sample 1 was measured by the same method as described in the method described in the evaluation described later. The absolute value of the resistance (Ω / D) of the sample 1 exceeded the upper limit of measurement (1.0 x 10 7 Ω / D) of the measuring device, and measurement could not be performed. That is, the specific resistance of the silicon thin film having a thickness of 5 nm was greater than 50,000 x 10 -4 Ω-cm. Note that the specific resistance of the sample 1 corresponds to the specific resistance of the first base layer (measured value of thin film) of Example 1.

[0141] A semimetal layer (first base layer 3) formed of silicon having a thickness of 3 nm was formed, and otherwise, the same operations as in the sample 1 were performed to prepare a sample 2, and the absolute value of the resistance was measured. The absolute value of the resistance of the sample 2 also exceeded the upper limit of measurement (1.0 x 10 7 Ω / D) of the measuring device, and measurement could not be performed. That is, the specific resistance of the silicon thin film having a thickness of 3 nm was greater than 30,000 x 10 -4 Ω-cm. Note that the specific resistance of the sample 2 corresponds to the specific resistance of the first base layer (measured value of thin film) of Examples 2 to 4.

[0142] The conditions of the magnetron sputtering method were set to be the same as in Comparative Example 2, except that the sample 3 was prepared in the same manner as the sample 1. That is, the sample 3 was provided with the first underlayer 3 of 5 nm in thickness formed of the semi-metal oxide layer on one face in the thickness direction of the base film 2. The resistance absolute value was also measured for the sample 3. The resistance absolute value of the sample 3 also exceeded the upper limit of the measurement device (1.0 x 10 7 Ω / □), and the measurement could not be performed. That is, the specific resistance of the semi-metal oxide layer of 5 nm in thickness was greater than 50,000 x 10 -4 Ω·cm. Note that the specific resistance of the sample 3 corresponds to the specific resistance of the first underlayer (measured value of the thin film) of Comparative Example 2.

[0143] [Resistance Absolute Value]

[0144] [Resistance Absolute Value]

[0145] The electrodes of each of the examples and the comparative examples were cut into a size of 210 x 297 mm, and the resistance absolute value was measured by the eddy current method using NC-80 LINE manufactured by NAPSON Co. The average value of the sheet resistance value except for the data of 10 mm at both ends in the long direction was used as the resistance absolute value by performing scanning of the non-contact measurement probe unit in the long direction. The results of the resistance absolute value are shown in Table 1. In addition, the resistance absolute value of the electrodes of Comparative Example 1, Comparative Examples 3 to 5 was multiplied by the thickness of the second underlayer 4, and the specific resistance of the second underlayer 4 (measured value of the thin film) was calculated. Note that, as described above, the specific resistance of the second underlayer 4 is sufficiently lower than the specific resistance of the conductive carbon layer 5, and thus the influence of the resistance absolute value (Ω / □) of the conductive carbon layer 5 on the electrode can be ignored. The results are shown in Table 1. Note that the specific resistance of the second underlayer 4 (measured value of the thin film) of Comparative Example 1, Comparative Examples 3 to 5 corresponds to the specific resistance of the second underlayer 4 (measured value of the thin film) of Examples 1 to 4.

[0146] [Reliability]

[0147] In each of the examples and the comparative examples, the reliability of the electrode was evaluated by the following method. That is, the electrodes of Example 1 and each of the comparative examples were cut into a size of 210 x 297 mm, and were stored for 1 month under room temperature and atmosphere. The resistance absolute value before storage and after storage was measured by the above-described method. The change rate of the resistance absolute value (reliability) was calculated from the resistance absolute value before storage and the resistance absolute value after storage based on the following equation. The results of the reliability are shown in Table 1.

[0148] Change rate of resistance absolute value (%) = (|resistance absolute value before storage - resistance absolute value after storage|) / resistance absolute value before storage x 100

[0149] [Table 1]

[0150]

[0151] The specific resistance (measured value of thin film) of the first base layer used in each of the embodiments is 10 times or more the specific resistance (measured value of thin film) of the second base layer. Note that in the measurement of the absolute value of resistance used in the specific resistance (measured value of thin film) of the first base layer and the specific resistance (measured value of thin film) of the second base layer, the measurement is performed in a state where the base material film is provided, but when the ratio of the specific resistances is compared, the effects cancel each other out, and thus can be ignored.

[0152] In each of the embodiments, the first base layer is a metal layer or a semi-metal layer, and the specific resistance (measured value of thin film) of the first base layer is 10 times or more the specific resistance (measured value of thin film) of the second base layer, and thus the absolute resistance value and reliability of the electrode are excellent. On the other hand, Comparative Example 1 and Comparative Examples 3 to 5 do not have the first base layer, and thus the reliability is poor. In addition, the first base layer of Comparative Example 2 is a semi-metal oxide layer, and thus the absolute resistance value is poor.

[0153] Note that the above-described application is provided as an example embodiment of the present application, but is simply an example and should not be interpreted restrictively. Variations of the present application that will be obvious to those skilled in the art are included in the scope of the preceding claims.

[0154] Industrial Applicability

[0155] The electrode of the present application can be suitably used as an electrode (working electrode) for electrochemical measurement.

[0156] Explanation of Reference Signs

[0157] 1 Electrode

[0158] 2 Base material film

[0159] 3 First base layer

[0160] 4 Second base layer

[0161] 5 Conductive carbon layer

Claims

1. An electrode comprising, in order toward a thickness direction side: a base material film; a first base layer; a second base layer; and a conductive carbon layer, the first base layer is a metal layer or a semi-metal layer, the second base layer is a metal layer, a specific resistance of the first base layer is 10 times or more of a specific resistance of the second base layer.

2. The electrode of claim 1, wherein, The electrically conductive carbon layer has sp 2 bonds and sp 3 bonds.

3. The electrode of claim 1, wherein, the second base layer contains titanium or niobium.

4. The electrode of claim 1, wherein, The specific resistance of the second base layer is 3.0 x 10 -4 Ω·cm or less.

5. The electrode of claim 1, wherein, the first base layer is a semi-metal layer and contains silicon.

6. The electrode of claim 1, wherein, a thickness of the first base layer is 3 nm or more.

7. The electrode according to any one of claims 1 to 6, which is an electrode for electrochemical measurement.

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