Nanostructure array, hydrogen detection element, and hydrogen detection device

Abstract

The present invention relates to a nanostructure array, a hydrogen detection element, and a hydrogen detection device. The nanostructure array comprises a substrate and a nanostructure formed on the substrate, wherein a plurality of the nanostructures are arranged in the nanostructure array, the nanostructure is formed of a metal having surface plasmons and having the property of absorbing and releasing hydrogen, the substrate is formed of a hydrogen responsive material that reacts with hydrogen and reversibly changes from a conductor to a dielectric, and surface plasmon resonance occurs due to light incident on the nanostructure.

Description

Technical Field

[0001] The present invention relates to a nanostructure array, a hydrogen detection element and a hydrogen detection device.

[0002] This application claims priority based on Japanese Patent Application No. 2019-028846, which was filed in Japan on February 20, 2019, the contents of which are incorporated herein by reference. Background Art

[0003] In recent years, the use of hydrogen has attracted much attention as a major next-generation energy source. On the other hand, hydrogen is a highly flammable gas, and in order to use it safely, it is necessary to quickly detect leaks.

[0004] Among them, due to safety concerns and low social awareness of hydrogen, the development of highly reliable hydrogen detection technology has become one of the most important issues in the promotion of hydrogen-based industries.

[0005] As conventional hydrogen detection methods, the contact combustion method and the semiconductor method are widely used. In addition to these methods, a hydrogen detection method in which the sensor unit is entirely composed of an optical system is also being studied.

[0006] For example, Patent Document 1 describes a technique for detecting hydrogen by using a hydrogen-sensitive chromatic mirror and detecting changes in the reflectivity and transmittance of light accompanying hydrogenation.

[0007] Patent Document 2 describes a technique for detecting hydrogen by detecting changes in optical frequency characteristics associated with hydrogen absorption in a surface plasmon resonance element having periodic openings formed in a thin film of palladium, which is a hydrogen absorption metal.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2005-265590

[0011] Patent Document 2: International Publication No. 2011 / 027899 Summary of the invention

[0012] However, in the above-mentioned prior art, it takes time for hydrogen to be absorbed and released by the hydrogen absorption metal, and there is a problem in the response speed of hydrogen. In addition, there is also a demand for further improvement in the detection sensitivity of hydrogen in the above-mentioned prior art.

[0013] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a hydrogen detection element and a hydrogen detection device that respond quickly to hydrogen and have improved hydrogen detection sensitivity, and a nanostructure array useful therefor.

[0014] In order to solve the above-mentioned problems, the present invention adopts the following configuration.

[0015] That is, the first embodiment of the present invention is a nanostructure array, characterized in that it comprises a substrate and a nanostructure formed on the substrate, and the nanostructure array is composed of a plurality of the above-mentioned nanostructures, the above-mentioned nanostructures are formed of a metal having surface plasmons and having the property of absorbing and releasing hydrogen, the above-mentioned substrate is formed of a hydrogen-responsive material that reacts with hydrogen and reversibly changes from a conductor to a dielectric, and surface plasmon resonance occurs when light is incident on the above-mentioned nanostructures.

[0016] A second aspect of the present invention is a hydrogen detecting element that detects hydrogen based on surface plasmon resonance, and includes the nanostructure array according to the first aspect of the present invention on a substrate.

[0017] The third embodiment of the present invention is a hydrogen detection device, characterized in that it comprises: the hydrogen detection element involved in the second embodiment of the present invention; a light source unit capable of emitting light to the hydrogen detection element; a light receiving unit for receiving the light passing through the hydrogen detection element; and a detection unit for detecting hydrogen based on the light reception result of the light receiving unit.

[0018] According to the present invention, it is possible to provide a hydrogen detection element and a hydrogen detection device that respond quickly to hydrogen and have improved hydrogen detection sensitivity, and a nanostructure array useful therefor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] [ Figure 1 ] is a diagram showing the schematic structure of the hydrogen detection device of this embodiment.

[0020] [ Figure 2 ] is a schematic cross-sectional view showing an embodiment of a hydrogen detection element.

[0021] [ Figure 3 ] is a stereoscopic diagram showing one embodiment of a nanostructure array.

[0022] [ Figure 4 ] is a stereoscopic diagram showing another embodiment of a nanostructure array.

[0023] [ Figure 5] is a graph showing the relationship between infrared light wavelength and reflectivity (reflection spectrum), measured using a Fourier transform infrared spectrophotometer (FT-IR) for a hydrogen detection device that applies each hydrogen detection element of Example 1 and Example 2, and Example 3 and Example 4.

[0024] Description of Reference Numerals

[0025] 10 Hydrogen detection element,

[0026] 12 substrate layer,

[0027] 14. Nanostructure array layer,

[0028] 30 light quantity measuring unit,

[0029] 40 Detection Department,

[0030] 100 Hydrogen detection device,

[0031] 200 nanostructure arrays,

[0032] 210 metal layer,

[0033] 220 laminated body,

[0034] 222 matrix,

[0035] 224 Nanostructures,

[0036] 300 nanostructure arrays,

[0037] 310 metal layer,

[0038] 322 base layer,

[0039] 324 Nanostructures DETAILED DESCRIPTION

[0040] A hydrogen detection device according to one embodiment of the present invention is characterized by the hydrogen detection element, and various known hydrogen detection devices can be appropriately applied to other configurations.

[0041] Figure 1 It is a diagram showing a schematic configuration of a hydrogen detection device according to this embodiment.

[0042] Figure 1 In the embodiment, the hydrogen detection device 100 is a hydrogen sensor that detects hydrogen using an optical method, and includes: a hydrogen detection element 10 ; a light quantity measuring unit 30 having a light source unit and a light receiving unit; and a detection unit 40 .

[0043] (Hydrogen detection element)

[0044] The hydrogen detecting element 10 in this embodiment includes a nanostructure array on a substrate. In the hydrogen detecting element 10, surface plasmon resonance occurs due to light incident on the nanostructure.

[0045] Figure 2 This is a schematic cross-sectional view in the thickness direction showing one embodiment of the hydrogen detecting element.

[0046] Figure 2 In the embodiment, the hydrogen detecting element 10 includes a nanostructure array layer 14 on a base layer 12 .

[0047] The thickness of the base material layer 12 is, for example, 100 to 2000 μm.

[0048] The thickness of the nanostructure array layer 14 is, for example, 300 to 500 nm.

[0049] Examples of the material for forming the base layer 12 include a silicon wafer, a sapphire substrate, a silica glass substrate, a quartz glass substrate, a borosilicate glass substrate, an alumina substrate, an acrylic resin film, and a polyimide resin film.

[0050] As the nanostructure array layer 14 in this embodiment, for example, Figure 3 The layer formed by the nanostructure array shown (first embodiment), Figure 4 The layer formed by the nanostructure array shown (second embodiment).

[0051] <First Embodiment>

[0052] Figure 3 FIG. 1 is a perspective view showing one embodiment of a nanostructure array.

[0053] Figure 3 In the embodiment, the nanostructure array 200 is obtained by arranging a plurality of stacked bodies 220 in a two-dimensional manner vertically and horizontally on a metal layer 210. The stacked body 220 is obtained by stacking a base 222 and a nanostructure 224.

[0054] In the nanostructure array 200 , the metal layer 210 is adjacent to the base 222 , the base 222 is disposed between the metal layer 210 and the nanostructure 224 , and the nanostructure 224 is disposed on the outermost surface.

[0055] The stacked body 220 in the nanostructure array 200 is substantially cylindrical, and its height (h1) is preferably, for example, 100 to 300 nm in view of the responsiveness to hydrogen and the detection sensitivity of hydrogen.

[0056] The radius (d1) of the stacked body 220 is set according to the detection target (resonance wavelength), and is preferably 100 to 800 nm, and more preferably 400 to 800 nm, for example.

[0057] From the perspective of responsiveness to hydrogen and detection sensitivity of hydrogen, the thickness of the base 222 is, for example, 50 to 200 nm.

[0058] The base 222 is made of a hydrogen-responsive material that reacts with hydrogen to reversibly change from a conductor to a dielectric, and is a material that changes the behavior of the surface plasmon resonance of the nanostructure 224 .

[0059] As a material forming the substrate 222, for example, yttrium, lanthanum series elements (lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium) and the like can be cited. Among these, from the aspects of responsiveness to hydrogen and detection sensitivity of hydrogen, it is preferred to include at least one selected from the group consisting of yttrium and lanthanum series elements, and it is particularly preferred to include at least yttrium. Yttrium is a substance that is a metal before absorbing hydrogen (Y), and reversibly changes to an insulator after absorbing hydrogen (YH3).

[0060] From the viewpoint of responsiveness to hydrogen and detection sensitivity of hydrogen, the thickness of the nanostructure 224 is, for example, 30 to 150 nm.

[0061] The nanostructure 224 is made of a metal having surface plasmons and a property of absorbing and releasing hydrogen, and is a material whose dielectric constant (refractive index) changes when hydrogen is absorbed.

[0062] As the material forming the nanostructure 224, for example, transition metal elements from the 7th group to the 11th group of the periodic table (about the transition metal elements from the 7th group to the 10th group of the periodic table, preferably the transition metal elements from the 5th period or the 6th period) etc. can be cited, wherein, palladium, precious metals other than palladium (gold, silver, platinum, rhodium, iridium, ruthenium, osmium) are preferred. Among these, from the aspect of hydrogen absorption and release of hydrogen, it is preferred that the metal at least comprises palladium, and the combination of palladium simple substance, palladium and gold is particularly preferred.

[0063] The size of the metal layer 210 can be appropriately determined according to the usage scenario and the like.

[0064] From the perspective of strength, responsiveness to hydrogen, and hydrogen detection sensitivity, the thickness of the metal layer 210 is, for example, 100 to 500 nm.

[0065] As materials for forming the metal layer 210, for example, transition metal elements from Group 7 to Group 11 of the periodic table such as gold, silver, copper, palladium, platinum, rhodium, and osmium (with respect to transition metal elements from Group 7 to Group 10 of the periodic table, transition metal elements from Period 5 or Period 6 are preferred); aluminum, cesium, or alloys selected from these elements. Among these, from the aspects of responsiveness to hydrogen and detection sensitivity of hydrogen, it is preferred to include at least one selected from the group consisting of gold, silver, copper, palladium, and platinum, more preferably to include at least one selected from the group consisting of gold and palladium, and particularly preferably to include at least gold.

[0066] Figure 3 In the embodiment, a plurality of stacked bodies 220 are arranged at a predetermined period (pitch) on the metal layer 210. In view of the responsiveness to hydrogen and the detection sensitivity of hydrogen, the distance (period) between the stacked bodies 220 is preferably greater than the diameter (2d1), and more preferably 1.1 to 2 times the diameter (2d1).

[0067] The hydrogen detecting element including a layer formed of the nanostructure array 200 according to the first embodiment on the base layer 12 can be produced, for example, by the following steps (A1) to (A4).

[0068] Step (A1): forming a metal layer 210 on the substrate layer 12 by thermal evaporation.

[0069] Step (A2): A positive photoresist is applied on the metal layer 210 by spin coating or the like to form a photoresist film. Thereafter, the photoresist film is exposed through a mask having an opening corresponding to the arrangement and diameter of the plurality of stacked bodies 220. Then, the photoresist film in the region where the plurality of stacked bodies 220 are formed is removed by development, and a photoresist pattern is formed on the metal layer 210.

[0070] Step (A3): A layer formed of a material forming the base 222 and a layer formed of a material forming the nanostructure 224 are sequentially stacked on the metal layer 210 on which the photoresist pattern is formed by sputtering or the like.

[0071] Step (A4): using an organic solvent or the like, the photoresist pattern formed on the metal layer 210 and the two layers stacked on the photoresist pattern are removed (ie, a lift-off method).

[0072] Alternatively, a hydrogen detecting element including a layer formed of the nanostructure array 200 according to the first embodiment on the base layer 12 may be manufactured by, for example, the following steps (B1) to (B4).

[0073] Step (B1): forming a metal layer 210 on the substrate layer 12 by thermal evaporation.

[0074] Step (B2): A layer formed of a material forming the base 222 and a layer formed of a material forming the nanostructure 224 are sequentially stacked on the metal layer 210 by sputtering or the like.

[0075] Step (B3): A negative photoresist is applied on the layer formed by the material forming the nanostructure 224 by spin coating or the like to form a photoresist film. Thereafter, the photoresist film is exposed through a mask having an opening corresponding to the configuration and diameter of the plurality of stacked bodies 220. Then, the photoresist film outside the region where the plurality of stacked bodies 220 are formed is removed by development, and a photoresist pattern is formed on the layer formed by the material forming the nanostructure 224.

[0076] Step (B4): The two layers stacked on the metal layer 210 in the area outside the photoresist pattern are removed by etching.

[0077] As described above, the hydrogen detecting element 10 of the present embodiment includes the specific nanostructure array 200 , and therefore the response to hydrogen is rapid, and the detection sensitivity of hydrogen is improved.

[0078] In the nanostructure array 200, the substrate 222 before hydrogen absorption is a conductor (metal), and the substrate 222 after hydrogen absorption reversibly changes to an insulator. Along with this, the behavior of the surface plasmon resonance changes before and after hydrogen absorption, so the optical properties change. That is, with respect to the hydrogen detection device 100, the detection sensitivity of hydrogen is improved, and the change amount of the reflectivity becomes larger.

[0079] In the nanostructure array 200 of the first embodiment described above, the stacked body 220 formed by stacking the base 222 and the nanostructures 224 is cylindrical, but the present invention is not limited thereto and may be a prism such as a quadrangular prism or a triangular prism.

[0080] In addition, in the laminated body 220 in the first embodiment, the base 222 and the nanostructure 224 have the same diameter, but the present invention is not limited thereto, and the shapes and sizes of the base 222 and the nanostructure 224 may be different.

[0081] In addition, the nanostructure array 200 of the first embodiment is obtained by arranging a plurality of stacked bodies 220 in a two-dimensional manner vertically and horizontally at a predetermined period (pitch) on the metal layer 210, but the present invention is not limited thereto. The arrangement of the plurality of stacked bodies 220 can be appropriately set according to the purpose and the like.

[0082] <Second Embodiment>

[0083] Figure 4 FIG. 4 is a perspective view showing another embodiment of a nanostructure array.

[0084] Figure 4 In FIG. 3 , the nanostructure array 300 is obtained by arranging a plurality of nanostructures 324 in a two-dimensional manner vertically and horizontally on a base layer 322 adjacent to a metal layer 310 .

[0085] In the nanostructure array 300 , the metal layer 310 and the base layer 322 are adjacent to each other, the base layer 322 is arranged between the metal layer 310 and the nanostructures 324 , and the nanostructures 324 are arranged on the outermost surface.

[0086] From the perspective of responsiveness to hydrogen and detection sensitivity of hydrogen, the thickness of the base layer 322 is, for example, 50 to 200 nm.

[0087] The base layer 322 is made of a hydrogen-responsive material that reacts with hydrogen to reversibly change from a conductor to a dielectric, and is a material that changes the behavior of the surface plasmon resonance of the nanostructure 324 .

[0088] Examples of a material for forming the base layer 322 include metal trioxides, metal pentoxides, and alloys containing magnesium.

[0089] Examples of the metal trioxide include WO 3 , MoO 3 , and ReO 3 .

[0090] Examples of the metal pentoxide include V2O5, Nb2O5, and Ta2O5.

[0091] Examples of the alloy containing magnesium include MgTi, NiMg, ErMg, GdMg, and SmMg.

[0092] Among these, as a material for forming the base layer 322, from the aspects of responsiveness to hydrogen and detection sensitivity of hydrogen, it is preferred to include at least one selected from the group consisting of metal trioxides, metal pentoxides, and alloys containing magnesium, more preferably at least metal trioxides, and particularly preferably at least WO3. Tungsten oxide is an insulator before absorbing hydrogen (WO3) and is a dielectric after absorbing hydrogen (H x WO3) is a substance that can reversibly change into a metal-like (conductor) state.

[0093] The nanostructures 324 in the nanostructure array 300 are substantially cylindrical, and their height (h2) is preferably, for example, 50 to 150 nm in view of the responsiveness to hydrogen and the detection sensitivity of hydrogen.

[0094] The radius (d2) of the nanostructure 324 is set according to the detection target (resonance wavelength), and is preferably 100 to 800 nm, and more preferably 400 to 800 nm, for example.

[0095] The nanostructure 324 is made of a metal having surface plasmons and the property of absorbing and releasing hydrogen, and is a material whose dielectric constant (refractive index) changes when hydrogen is absorbed.

[0096] As the material forming the nanostructure 324, for example, transition metal elements from the 7th group to the 11th group of the periodic table (about the transition metal elements from the 7th group to the 10th group of the periodic table, preferably the transition metal elements from the 5th period or the 6th period) etc. can be cited, wherein, palladium, precious metals other than palladium (gold, silver, platinum, rhodium, iridium, ruthenium, osmium) are preferred. Among these, from the aspect of hydrogen absorption and release of hydrogen, it is preferred that the metal at least comprises palladium, and the combination of palladium simple substance, palladium and gold is particularly preferred.

[0097] The size of the metal layer 310 can be appropriately determined according to the usage scenario and the like.

[0098] From the perspective of strength, responsiveness to hydrogen, and hydrogen detection sensitivity, the thickness of the metal layer 310 is, for example, 100 to 500 nm.

[0099] As materials for forming the metal layer 310, for example, transition metal elements from Group 7 to Group 11 of the periodic table such as gold, silver, copper, palladium, platinum, rhodium, and osmium (with respect to transition metal elements from Group 7 to Group 10 of the periodic table, transition metal elements from Period 5 or Period 6 are preferred); aluminum, cesium, or alloys selected from these elements. Among these, from the aspects of responsiveness to hydrogen and detection sensitivity of hydrogen, it is preferred to include at least one selected from the group consisting of gold, silver, copper, palladium, and platinum, more preferably to include at least one selected from the group consisting of gold and palladium, and particularly preferably to include at least gold.

[0100] Figure 4 In the embodiment, a plurality of nanostructures 324 are arranged at a predetermined period (pitch) on the base layer 322. From the perspective of responsiveness to hydrogen and detection sensitivity of hydrogen, the distance (period) between the nanostructures 324 is preferably greater than the diameter (2d2), and more preferably 1.1 to 2 times the diameter (2d2).

[0101] The hydrogen detecting element including the layer formed of the nanostructure array 300 according to the second embodiment on the base layer 12 can be manufactured by, for example, the following steps (C1) to (C5).

[0102] Step (C1): forming a metal layer 310 on the substrate layer 12 by thermal evaporation.

[0103] Step (C2): forming a base layer 322 on the metal layer 310 by sputtering or the like.

[0104] Step (C3): A positive photoresist is applied on the base layer 322 by spin coating or the like to form a photoresist film. Thereafter, the photoresist film is exposed through a mask having an opening corresponding to the arrangement and diameter of the plurality of nanostructures 324. Then, the photoresist film in the region where the plurality of nanostructures 324 are formed is removed by development to form a photoresist pattern on the base layer 322.

[0105] Step (C4): A layer formed of a material for forming the nanostructure 324 is stacked on the base layer 322 on which the photoresist pattern is formed by sputtering or the like.

[0106] Step (C5): Using an organic solvent or the like, the photoresist pattern formed on the base layer 322 and the layers stacked on the photoresist pattern are removed (ie, a lift-off method).

[0107] Alternatively, a hydrogen detecting element including a layer formed of the nanostructure array 300 according to the second embodiment on the base layer 12 may be manufactured by, for example, the following steps (D1) to (D4).

[0108] Step (D1): forming a metal layer 310 on the substrate layer 12 by thermal evaporation.

[0109] Step (D2): The base layer 322 and a layer formed of a material for forming the nanostructure 324 are sequentially stacked on the metal layer 310 by sputtering or the like.

[0110] Step (D3): A negative photoresist is applied on the layer formed by the material forming the nanostructure 324 by spin coating or the like to form a photoresist film. Thereafter, the photoresist film is exposed through a mask having an opening corresponding to the arrangement and diameter of the plurality of nanostructures 324. Then, the photoresist film outside the region where the plurality of nanostructures 324 are formed is removed by development, and a photoresist pattern is formed on the layer formed by the material forming the nanostructure 324.

[0111] Step (D4): The layer formed of the material forming the nanostructure 324 and stacked on the base layer 322 in the area outside the photoresist pattern is removed by etching.

[0112] As described above, the hydrogen detecting element 10 of the present embodiment has the specific nanostructure array 300 , and therefore responds quickly to hydrogen and has improved hydrogen detection sensitivity.

[0113] In the nanostructure array 300, the substrate 322 before hydrogen absorption is an insulator, and the substrate layer 322 after hydrogen absorption reversibly changes to a metalloid (metal). Along with this, the behavior of the surface plasmon resonance changes before and after hydrogen absorption, so the optical properties change. That is, with respect to the hydrogen detection device 100, the detection sensitivity of hydrogen is improved, and the change amount of the reflectivity becomes larger.

[0114] In the nanostructure array 300 of the second embodiment described above, the nanostructures 324 are cylindrical, but the present invention is not limited thereto and may be prisms such as quadrangular prisms or triangular prisms.

[0115] In addition, the nanostructure array 300 of the second embodiment is obtained by arranging a plurality of nanostructures 324 in a two-dimensional manner vertically and horizontally at a predetermined period (pitch) on the base layer 322, but is not limited thereto. The arrangement of the plurality of nanostructures 324 can be appropriately set according to the purpose and the like.

[0116] <Other Implementation Methods>

[0117] In the hydrogen detection element 10 of the first embodiment described above, a plurality of stacked bodies 220 (obtained by stacking a substrate 222 and a nanostructure 224) are arranged on the metal layer 210, but it is not limited thereto, and it may also be configured as follows: a plurality of nanostructures 224 are arranged in a two-dimensional manner vertically and horizontally on a substrate layer (a layer formed by the substrate 222) adjacent to the metal layer 210. However, there are substances with high oxidizability in the material forming the substrate 222, such as yttrium Y. Therefore, it is preferred to cover the exposed portion of the substrate layer (a layer formed by the substrate 222) with an anti-oxidation film in advance.

[0118] Each of the hydrogen detecting elements 10 of the first and second embodiments described above is configured to include the metal layers 210 and 310 , but the present invention is not limited thereto and the element may be configured to lack the metal layers 210 and 310 .

[0119] That is, the hydrogen detection element may be configured as a plurality of stacked bodies of a substrate and a nanostructure arranged on a substrate layer (the third embodiment), or the hydrogen detection element may be configured as a plurality of nanostructures arranged on a substrate layer adjacent to the substrate layer (the fourth embodiment).

[0120] The hydrogen detecting device to which the hydrogen detecting element of the third embodiment or the fourth embodiment is applied may be configured to receive infrared light transmitted through the hydrogen detecting element or to receive infrared light reflected by the hydrogen detecting element.

[0121] According to the third embodiment or the fourth embodiment, a hydrogen detecting element in a metal hole array format or a nanodisk array format can be employed.

[0122] (Hydrogen detection device)

[0123] A hydrogen detection device according to one embodiment of the present invention comprises: a hydrogen detection element; a light source unit capable of emitting light to the hydrogen detection element; a light receiving unit for receiving the light passing through the hydrogen detection element; and a detection unit for detecting hydrogen based on a light reception result of the light receiving unit.

[0124] Figure 1 The hydrogen detection device 100 shown includes: a hydrogen detection element 10 ; a light quantity measurement unit 30 including a light source unit and a light receiving unit; and a detection unit 40 .

[0125] In the hydrogen detecting device 100 of the present embodiment, the present invention is applied to the hydrogen detecting element 10 (the nanostructure array layer 14 is provided on the base layer 12). The nanostructure array layer 14 can adopt the nanostructure array of the first embodiment or the second embodiment described above.

[0126] The hydrogen detecting element 10 is housed in the chamber 20 .

[0127] A pipe 94 for introducing a mixed gas containing hydrogen from the outside and a pipe 95 for discharging the mixed gas to the outside are connected to the chamber 20. The chamber 20 is also connected to a mixer 93 via the pipe 94.

[0128] In the mixer 93 , the nitrogen supplied from the nitrogen supply unit 91 and the hydrogen-containing gas supplied from the hydrogen supply unit 92 are mixed at a predetermined mixing ratio.

[0129] The hydrogen detection device 100 of this embodiment can detect hydrogen contained in the mixed gas when the concentration is, for example, 4 volume % or more, and can fully detect hydrogen even when it is 1 volume % or more. By appropriately selecting a nanostructure array, etc., it can also detect hydrogen even when it is 0.01 volume % or more.

[0130] The flow rate of the mixed gas flowing from the mixer 93 into the chamber 20 can be appropriately set according to the scale of the device, etc. For example, when the capacity of the chamber 20 is 1.5L, the flow rate of the mixed gas is preferably set to 1500mL / h or more, and the higher the flow rate per unit time, the better.

[0131] In the hydrogen detection device 100 of this embodiment, the light quantity measuring unit 30 has both a light source unit and a light receiving unit. The light quantity measuring unit 30, as a light source unit, emits light of a predetermined wavelength to the hydrogen detection element 10 in the chamber 20. The light emitted by the light source unit can be appropriately selected according to the size of the nanostructure, for example, infrared light can be cited, and preferably near infrared to mid-infrared light can be cited.

[0132] The light quantity measuring unit 30 serves as a light receiving unit and receives light reflected by the hydrogen detecting element 10. The light quantity measuring unit 30 outputs information received by the light receiving unit to the detecting unit 40.

[0133] As the light quantity measuring unit 30 , for example, a spectrophotometer such as a Fourier transform infrared spectrophotometer (FT-IR) can be used.

[0134] The detection unit 40 detects hydrogen by performing calculation based on surface plasmon resonance according to the light reception result of the light receiving unit in the light quantity measuring unit 30. Specifically, the detection unit 40 detects hydrogen according to the difference between the reflectivity of infrared light before hydrogen absorption and the reflectivity of infrared light after hydrogen absorption of the hydrogen detection element 10 based on the received information.

[0135] In the hydrogen detection device 100 of this embodiment, light (for example, infrared light with a wavelength of 1300 nm) emitted from the light source unit of the light quantity measuring unit 30 illuminates the hydrogen detecting element 10 , and a portion of the light is reflected by the hydrogen detecting element 10 and enters the light receiving unit in the light quantity measuring unit 30 .

[0136] A mixed gas containing hydrogen is supplied from the mixer 93 to the chamber 20. In the hydrogen detection element 10 housed in the chamber 20, surface plasmon resonance occurs by light incident on the nanostructure. Moreover, the metal constituting the nanostructure array absorbs hydrogen. The hydrogen absorbed in the metal is purified in the metal, diffuses into the matrix and reacts with the hydrogen responsive material. Along with this, the behavior of the surface plasmon resonance changes before and after the absorption of hydrogen, so the optical properties change. In the hydrogen detection device 100, the reflection spectrum shifts to the short wavelength or long wavelength side. In this way, the hydrogen contained in the mixed gas is detected, and the hydrogen detection device 100 acts as a hydrogen sensor.

[0137] In addition, the hydrogen detection device 100 of the present embodiment preferably uses a hydrogen detection element that is exposed to hydrogen in advance before being used for hydrogen detection.

[0138] When the hydrogen detecting element of the first embodiment or the second embodiment described above is used as the hydrogen detecting element 10, the element is preferably exposed to hydrogen for 0.5 hours or more and 2 days or less, and more preferably 1 hour or more and 1 day or less before being used for hydrogen detection. By using the hydrogen detecting element pre-exposed to hydrogen within the above-mentioned preferred time range, the response to hydrogen is accelerated and the detection sensitivity of hydrogen is also improved.

[0139] When using a hydrogen detection element pre-exposed to hydrogen, the reflection spectrum is shifted to the short wavelength side in the hydrogen detection device 100 to which the hydrogen detection element of the first embodiment is applied. The reflection spectrum is shifted to the long wavelength side in the hydrogen detection device 100 to which the hydrogen detection element of the second embodiment is applied. That is, the hydrogen detection device 100 has excellent responsiveness to hydrogen and detection sensitivity of hydrogen.

[0140] In the nanostructure arrays 200 and 300 of the present embodiment, the nanostructures 224 and 324 are formed on the substrates 222 and 322, respectively, so the response to hydrogen is rapid, and the detection sensitivity of hydrogen is improved. In addition, the nanostructure arrays 200 and 300 are provided with metal layers 210 and 310, respectively, so that the detection sensitivity of hydrogen is particularly improved.

[0141] The hydrogen detection device 100 of the above-described embodiment is configured to receive light reflected by the hydrogen detection element 10 , but is not limited thereto. For example, the device may be configured to receive light transmitted through the hydrogen detection element 10 or diffracted light.

[0142] [Example]

[0143] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

[0144] <Manufacturing of Hydrogen Detection Element>

[0145] The following are respectively produced and Figure 2 The hydrogen detecting element 10 shown is a hydrogen detecting element of the same embodiment, that is, a hydrogen detecting element including a nanostructure array layer on a base layer.

[0146] The hydrogen detecting elements of Examples 1, 2, 5 to 12 include Figure 3 The nanostructure array layer is the same as that of the first embodiment shown.

[0147] The hydrogen detecting elements of Examples 3, 4, 13 to 20 are provided with Figure 4 The nanostructure array layer is the same as the second embodiment shown.

[0148] (Example 1)

[0149] Step (a1): A chromium (Cr) layer with a thickness of 3 nm and a gold (Au) layer with a thickness of 200 nm are deposited in sequence on a glass substrate by thermal evaporation.

[0150] Step (a2): A photoresist pattern (a pattern of holes with a radius of 400 nm and a period of 1.5 times the diameter) is formed on the gold (Au) layer by electron beam lithography.

[0151] Step (a3): Using electron beam evaporation, a 100 nm thick yttrium (Y) layer and a 50 nm thick palladium (Pd) layer are sequentially deposited on the gold (Au) layer having the photoresist pattern formed thereon.

[0152] Step (a4): Using a lift-off method, the photoresist pattern formed on the gold (Au) layer and the two layers (yttrium (Y) layer and palladium (Pd) layer) stacked on the photoresist pattern are removed.

[0153] As a result, a hydrogen detecting element was obtained having a nanodisk array layer in which a disk-shaped stack (Y layer and Pd layer) with a radius of 400 nm was arranged two-dimensionally vertically and horizontally on a gold (Au) layer (period: 1.5 times the diameter).

[0154] (Example 2)

[0155] The same operation as in Example 1 was performed to carry out steps (a1) to (a4). After that, pure hydrogen exposure was performed for 1 hour to obtain a hydrogen detection element of Example 2 having a nanodisk array layer in which a stacked body (Y layer and Pd layer) having a disk shape with a radius of 400 nm was arranged vertically and horizontally two-dimensionally on a gold (Au) layer (period: 1.5 times the diameter).

[0156] (Example 3)

[0157] Step (c1): A chromium (Cr) layer with a thickness of 3 nm and a gold (Au) layer with a thickness of 200 nm are deposited in sequence on a glass substrate by thermal evaporation.

[0158] Step (c2): using electron beam evaporation, a 100 nm thick tungsten oxide WO3 layer is deposited on the gold (Au) layer.

[0159] Step (c3): A photoresist pattern (a pattern of holes with a radius of 400 nm and a period of 1.5 times the diameter) is formed on the tungsten oxide (WO3) layer by electron beam lithography.

[0160] Step (c4): A palladium (Pd) layer having a thickness of 50 nm is deposited on the tungsten oxide (WO 3 ) layer having a photoresist pattern formed thereon by electron beam evaporation.

[0161] Step (c5): using a lift-off method, the photoresist pattern formed on the tungsten oxide (WO3) layer and the palladium (Pd) layer stacked on the photoresist pattern are removed.

[0162] As a result, a hydrogen detecting element was obtained having a nanodisk array layer in which disk-shaped palladium (Pd) nanostructures with a radius of 400 nm were arranged two-dimensionally (period: 1.5 times the diameter) on a WO3 layer adjacent to a gold (Au) layer.

[0163] (Example 4)

[0164] The same operation as in Example 3 was performed to carry out steps (c1) to (c5). After that, pure hydrogen exposure was performed for 1 hour to obtain a hydrogen detection element of Example 4 having a nanodisk array layer in which palladium (Pd) nanostructures with a radius of 400 nm were arranged in a two-dimensional manner vertically and horizontally on a WO3 layer adjacent to a gold (Au) layer (period: 1.5 times the diameter).

[0165] (Examples 5 to 12)

[0166] Except for changing the radius of the hole to 450nm, 500nm, 550nm, 600nm, 650nm, 700nm, 750nm and 800nm ​​respectively in the above step (a2), the same operation as in Example 2 is carried out, steps (a1) to (a4) and pure hydrogen exposure for 1 hour are performed to obtain the hydrogen detection elements of Examples 5 to 12.

[0167] (Examples 13 to 20)

[0168] Except for changing the radius of the hole to 450nm, 500nm, 550nm, 600nm, 650nm, 700nm, 750nm and 800nm ​​respectively in the above step (c3), the same operation as in Example 4 is carried out, steps (c1) to (c5) and pure hydrogen exposure for 1 hour are performed to obtain the hydrogen detection elements of Examples 13 to 20.

[0169] (Comparative Example 1)

[0170] A 3 nm thick chromium (Cr) layer and a 200 nm thick gold (Au) layer were deposited on a glass substrate in sequence by thermal evaporation. Next, a 100 nm thick yttrium (Y) layer and a 50 nm thick palladium (Pd) layer were deposited on the entire surface of the gold (Au) layer in sequence by electron beam evaporation. After that, pure hydrogen exposure was performed for 4 seconds to obtain a hydrogen detection element of Comparative Example 1 formed of a laminate of Au layer / Y layer / Pd layer.

[0171] <Evaluation>

[0172] Production and Figure 1The hydrogen detection device 100 shown is a device of the same embodiment, in which a mixed gas is supplied into a chamber and a reflection spectrum is measured.

[0173] The hydrogen detecting element 10 is applied to each of the hydrogen detecting elements of Examples 1 to 20 and Comparative Example 1. A Fourier transform infrared spectrophotometer (FT-IR) is used as the light quantity measuring unit 30 including a light source unit and a light receiving unit.

[0174] [Measurement conditions]

[0175] Light emitted from the light source section in the light quantity measuring section 30: infrared light with a wavelength of 1300 nm

[0176] ·Ratio of mixed gas: Nitrogen / Hydrogen=96 / 4 (volume ratio)

[0177] · Flow rate of mixed gas supplied from mixer 93 to chamber 20: 1500 mL / h

[0178] Figure 5 This is a graph showing the relationship between infrared light wavelength and reflectance (reflection spectrum) measured using a Fourier transform infrared spectrophotometer (FT-IR). The horizontal axis represents wavelength (μm) and the vertical axis represents reflectance (%).

[0179] Figure 5 This is a graph showing the relationship between infrared light wavelength and reflectivity (reflection spectrum) measured using a Fourier transform infrared spectrophotometer (FT-IR) for hydrogen detection devices that apply the hydrogen detection elements of Examples 1 and 2, and Examples 3 and 4.

[0180] When the hydrogen detecting element of Comparative Example 1 is used, the hydrogen response speed is about the same as that of the hydrogen detecting element of Example 2. On the other hand, when the hydrogen detecting element of Comparative Example 1 is used, the change in reflectivity is very small, and the hydrogen detection sensitivity is very weak.

[0181] It should be noted that for the hydrogen detection element of Comparative Example 1 formed by the stack of Au layer / Y layer / Pd layer, it was confirmed that: when pure hydrogen exposure was started, it reacted with hydrogen within 4 seconds (hydrogen absorption); when pure hydrogen exposure was stopped, hydrogen was released after 4 seconds.

[0182] Figure 5 In the case of using the hydrogen detection element of Example 2, a depression was observed where the reflectance became extremely small at a specific wavelength. This confirmed that the detection sensitivity of hydrogen was further improved by providing the nanostructure array.

[0183] Comparison of the application of each hydrogen detection element of Example 1 and Example 2:

[0184] The reflection spectrum when the hydrogen detection element of Example 2 was used was observed to be shifted to the short wavelength side (blue shift) compared to the reflection spectrum when the hydrogen detection element of Example 1 was used, and the depression where the reflectivity became extremely small at a specific wavelength was more significant (transmittance became higher). This confirmed that the response to hydrogen was accelerated by exposing the pure hydrogen for 1 hour before the hydrogen detection test, and the hydrogen detection sensitivity was also improved.

[0185] It should be noted that, regarding the hydrogen detecting element of Example 2, it is presumed that yttrium (Y) changes from Y to YH2 by exposing to pure hydrogen for 1 hour, making it easier for surface plasmon resonance to occur, thereby obtaining a shift in the reflection spectrum.

[0186] Comparison of the application of the hydrogen detection elements of Example 3 and Example 4:

[0187] The reflection spectrum of the hydrogen detection element of Example 4 was confirmed to be shifted to the long wavelength side (red shifted) and the reflectivity was improved compared with the reflection spectrum of the hydrogen detection element of Example 3. This confirmed that the response to hydrogen was accelerated and the detection sensitivity of hydrogen was improved by pre-exposing to pure hydrogen for 1 hour before the hydrogen detection test.

[0188] It should be noted that, regarding the hydrogen detection element of Example 4, it is presumed that the tungsten oxide WO3 is exposed to pure hydrogen for 1 hour, thereby changing from WO3 to H x In the state of WO3, the surface plasmon resonance is easily eliminated, so the reflection spectrum is shifted.

[0189] When the hydrogen detecting elements of Examples 5 to 12 were used, reflection spectra showing the same changes as those obtained when the hydrogen detecting element of Example 2 was used were obtained. However, the reflection spectra shifted toward the longer wavelength side as the disk radius increased.

[0190] When the hydrogen detecting elements of Examples 13 to 20 were used, reflection spectra showing the same changes as those obtained when the hydrogen detecting element of Example 4 was used were obtained. However, the reflection spectra shifted toward the longer wavelength side as the disk radius increased.

[0191] From the above, it was confirmed that the hydrogen detecting device using the hydrogen detecting element to which the hydrogen detecting elements of Examples 1, 2, and 5 to 12 were applied functioned as a hydrogen sensor.

[0192] Furthermore, it was confirmed that a hydrogen detecting device using the hydrogen detecting element to which the hydrogen detecting elements of Examples 3, 4, and 13 to 20 were applied operated as a hydrogen sensor.

[0193] Industrial Applicability

[0194] The hydrogen detection element and hydrogen detection device of the present invention can be widely used in equipment using hydrogen as fuel to detect hydrogen leakage, etc. The hydrogen detection element and hydrogen detection device of the present invention can be set in, for example, a fuel cell, a vehicle using hydrogen as energy, a gas turbine using hydrogen as energy, etc.

Claims

1. A nanostructure array comprising a substrate and a nanostructure formed on the substrate, wherein the nanostructure array comprises a plurality of the nanostructures arranged therein. The substrate and the nanostructure are stacked to form a disc-shaped stack. The nanostructure is formed of a metal having surface plasmons and the property of absorbing and releasing hydrogen, and the thickness of the nanostructure is 30 to 150 nm. The substrate is formed of a hydrogen-responsive material that reacts with hydrogen to reversibly change from a conductor to a dielectric, and the thickness of the substrate is 50 to 200 nm. Surface plasmon resonance occurs due to light incident on the nanostructure.

2. The nanostructure array according to claim 1, wherein: The nanostructure is formed of a metal including at least palladium.

3. The nanostructure array according to claim 1, wherein: The hydrogen responsive material includes at least one selected from the group consisting of yttrium and lanthanide elements.

4. The nanostructure array according to claim 1, wherein: The hydrogen responsive material includes at least one selected from the group consisting of metal trioxides, metal pentoxides, and alloys including magnesium.

5. The nanostructure array according to claim 1, further comprising a metal layer, wherein the metal layer comprises at least one selected from the group consisting of gold, silver, copper, palladium and platinum, The metal layer is adjacent to the substrate, and the substrate is arranged between the metal layer and the nanostructure.

6. A hydrogen detection element, which is a hydrogen detection element that detects hydrogen based on surface plasmon resonance, The hydrogen detecting element comprises the nanostructure array according to claim 1 on a substrate.

7. A hydrogen detection device having: The hydrogen detection element according to claim 6; a light source unit capable of emitting light to the hydrogen detecting element; a light receiving unit that receives the light that has passed through the hydrogen detecting element; and A detection unit detects hydrogen based on the light reception result of the light receiving unit.

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