Hydrogen sensor and design method

Abstract

The invention discloses a hydrogen sensor and a design method, the hydrogen sensor comprises a rigid frame, the rigid frame is filled with a deformation material to form a first deformation layer, and the surface of the first deformation layer is sequentially provided with a gas sensitive layer made of a gas sensitive material and a top shell made of a hard material; a light-transmitting part is reserved on the rigid frame, and a micro-nano structure is arranged on the surface of the first deformation layer at the light-transmitting part; the rigid frame, the first deformation layer, the gas-sensitive layer and the top shell are designed to form a deformation quantity transfer structure, deformation generated after the gas-sensitive layer absorbs hydrogen is accumulated and transferred to a micro-nano structure with a smaller area, and the deformation of the gas-sensitive layer is converted into the deformation of the micro-nano structure, namely, time accumulation is converted into area quantity; all the areas in contact with hydrogen at the same time are deformed, so that the variable quantity of the micro-nano structure is amplified, the time required to be accumulated is converted into the volume advantage of the gas sensitive layer, and finally, quick response is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of gas sensors, and particularly relates to a hydrogen sensor and a design method thereof. Background Art

[0002] Hydrogen is an important chemical raw material and also an important clean energy source, so it has been widely used. In the aerospace industry, hydrogen has become the main fuel for spacecraft engines. Hydrogen molecules are very small and prone to leakage during storage and transportation. When the hydrogen content in the air reaches more than 4%, a strong explosion may occur; in a vacuum, although hydrogen is not easily explosive, even a very small leakage (leakage rate of 10-8 Pa·m3 / s) can significantly shorten the life of the hydrogen battery carried by the spacecraft. Therefore, with the wide application of hydrogen, the research on low-concentration hydrogen detection technology is of great significance.

[0003] At present, there are many types of hydrogen sensors on the market. According to different working principles, they are mainly divided into several types such as electrochemical sensors, semiconductor sensors, thermoelectric hydrogen sensors, and fiber optic sensors. The working principle of an electrochemical hydrogen sensor is to work by chemically reacting with the gas to be detected and generating an electrical signal proportional to the gas concentration. The disadvantages of this sensor are its high price, short service life, and susceptibility to external environmental conditions such as temperature, pressure, and humidity. A semiconductor sensor is a sensor made by utilizing the property that the properties of semiconductors are easily affected by external conditions, using ZnO, SnO2, WO3, etc. as the gas-sensitive materials. The disadvantage is that the baseline is prone to drift, and the signal is easy to saturate when monitoring high-concentration hydrogen. The working principle of a thermoelectric hydrogen sensor is to place the hydrogen-sensitive element in a hydrogen environment, where hydrogen reacts with oxygen under the catalysis of a catalyst in the hydrogen sensor to generate water vapor and release heat, and then use a thermocouple to measure the temperature and combine a processing program to calculate and output the hydrogen concentration. The disadvantages are high working temperature, weak output signal, and low sensitivity. A fiber optic sensor is a method of detecting the volume fraction of hydrogen in a gas by measuring changes in optical parameters such as the transmittance and reflectivity of a thin film using fiber optic technology. Platinum and its alloys are often used as the hydrogen-sensitive materials for fiber optic hydrogen sensors. The disadvantages are weak output signal and short service life. In addition, the hydrogen-sensitive materials of fiber optic hydrogen sensors are all precious metals such as Pt, and the cost is high. Most importantly, the above types of hydrogen sensors are likely to give false alarms and cannot truly achieve accurate detection of hydrogen concentration. For example, it has been reported that In2O3 can be used as a gas-sensitive element for gases such as H2, NH3, and CO2. However, because In2O3 is a semiconductor-type sensor material, H2, NH3, etc. can all react with this type of hydrogen sensor. Therefore, when measuring H2, if there are gases such as NH3 and CO2, the sensor will also alarm, resulting in false alarms.

[0004] Therefore, the defects of the above types of sensors are as follows: (1) Insufficient detection accuracy: The problem of weak output signals of hydrogen sensors is a common one. The reason can be considered that when hydrogen sensors convert hydrogen concentration into measurable physical quantities such as resistance, capacitance, and temperature, the measurement accuracy is reduced, and microscopic changes are converted into macroscopic signals, which poses higher requirements for the detection of low-concentration signal changes. (2) Slow response speed at low concentrations: Whether it is a capacitive, resistive, electrochemical, or optical gas sensor, its principle is to detect the physical or chemical changes generated after the gas-sensitive material combines with hydrogen. At lower concentrations, smaller signal changes are more difficult to detect, resulting in detector failure. Current solutions, such as capacitive ones, can achieve the accumulation of signal strength and finally reach the detectable range. The disadvantage is that the response time is sacrificed. It is reported that the response time of the detectors prepared by them can reach about 30 minutes at low concentrations (and even some products have response times of several hours).

[0005] The working characteristics of palladium (palladium alloy) hydrogen sensors are determined by the properties of the hydrogen-sensitive material itself, such as sensitivity, stability, and service life. When the gas-sensitive material encounters a hydrogen-containing environment, hydrogen adsorption occurs, and its physical or chemical properties change accordingly. Hydrogen sensors detect signals based on this principle and obtain the relationship between hydrogen and these physical or chemical property changes. From the current research situation, mainly the physical properties of the hydrogen-sensitive material change after hydrogen absorption. These physical properties include: crystal structure, thermal stability, electrical properties, and surface wavelength, etc. Among these hydrogen-sensitive materials, metallic palladium shows the most obvious performance, and it has high selectivity for hydrogen. The hydrogen absorption range of pure palladium is limited. When the hydrogen concentration is high, pure palladium will undergo hydrogen embrittlement and cause the film to fall off, resulting in the failure of hydrogen sensors made of pure palladium at high hydrogen concentrations. Adding metals such as silver and nickel to palladium can well stabilize the palladium-hydrogen alloy and prevent the palladium hydride compound from transforming from the α phase to the β phase. These palladium alloys have good reversibility and fast response ability at room temperature. Therefore, the palladium alloy system has currently become an important source of hydrogen-sensitive materials for hydrogen sensors.

[0006] In the related art, a patent application document with publication number CN104749101A proposed an optical hydrogen sensor. The optical principle is that after the gas-sensitive material absorbs hydrogen, it deforms, and then the deformation signal is converted into an electrical signal through an optical signal. However, this solution completely relies on the deformation amount of the micro-nano structure per unit area, which is not conducive to improving the sensitivity and the response time in a low-concentration hydrogen environment. Moreover, the material structure used in it causes no signal difference at the peak of its measurement curve (the most sensitive position of the signal), which will reduce the sensitivity. In the patent application document with publication number CN110389122A, a fluorescence-enhanced all-fiber hydrogen sensor based on metamaterials was proposed. Its detection principle is that after the hydrogen-sensitive layer expands, it stretches the metamaterial layer, thereby changing the period of the metamaterial, and further changing the resonance coupling relationship between the incident light and the metamaterial, making the intensity of the surface local optical field change. However, since the deformation of the gas-sensitive material itself is small and it has to drive the substrate material under the micro-nano structure, that is, the material carrying the metasurface structure. Since the deformation of the gas-sensitive material has to drive the carrier under the metasurface to cause the deformation of the metasurface structure, the deformation efficiency of the gas-sensitive material causing the deformation of the micro-nano material is surely not high. Moreover, a fluorescence probe needs to be used, and the fluorescence probe will also fall off, resulting in failure. Laser and metamaterial resonance coupling also need to be used, and the cost and energy consumption are relatively high. Summary of the Invention

[0007] The technical problem to be solved by the present invention lies in how to improve the response sensitivity in a low-concentration hydrogen environment.

[0008] The present invention solves the above technical problem by the following technical means:

[0009] A hydrogen sensor is proposed, which includes a rigid frame. The rigid frame is filled with a deformation material to form a first deformation layer. A gas-sensitive layer made of a gas-sensitive material and a top shell made of a hard material are sequentially arranged on the surface of the first deformation layer. The rigid frame reserves a light-transmitting part, and a micro-nano structure is arranged on the surface of the first deformation layer at the light-transmitting part.

[0010] Further, the rigid frame forms an I-shaped structure after being filled with the deformation material.

[0011] Further, the deformation material is polydimethylsiloxane.

[0012] Further, the gas-sensitive material is a palladium-gold alloy.

[0013] Further, the hard material is a hard porous material.

[0014] Further, the rigid frame is prepared from ceramics.

[0015] Further, the rigid frame includes upper and lower support plates. Two connecting plates are arranged between the upper support plate and the lower support plate to form a cavity, and the upper support plate communicates with the cavity;

[0016] The upper support plate and the cavity are filled with the deformation material to form an I-shaped structure.

[0017] Further, light-transmitting holes are formed in both of the connecting plates to form the light-transmitting part, or light-transmitting holes are formed in one of the connecting plates to form the light-transmitting part.

[0018] Further, the micro-nano structure includes a second deformation layer, and a nano-column array formed by a metasurface thin film is disposed on the surface of the second deformation layer.

[0019] Further, the micro-nano structure includes a second deformation layer, a base layer, an insulating layer, and a nano-column array formed by a metasurface thin film which are arranged in sequence;

[0020] The base layer is made of a metal material, and the insulating layer is prepared from a dielectric material.

[0021] In addition, the present invention also provides a design method of a hydrogen sensor as described above, including:

[0022] Preparing a rigid frame by replication using a master mold;

[0023] Filling the rigid frame with a deformation material to form a first deformation layer;

[0024] Evaporating or sputtering a gas-sensitive material on the surface of the first deformation layer to form a gas-sensitive layer;

[0025] Coating a hard material on the gas-sensitive layer to form a top shell;

[0026] Fabricating a micro-nano structure, where the deformation material is used as the base layer of the micro-nano structure;

[0027] Fixing the micro-nano structure on the surface of the first deformation layer at the light-transmitting part to form a hydrogen sensor.

[0028] Further, the preparing a rigid frame by replication using a master mold includes:

[0029] Printing and preparing a first master mold corresponding to a transmissive sensor, and preparing a first rigid frame by replication using the first master mold;

[0030] Printing and preparing a second master mold corresponding to a reflective sensor, and preparing a second rigid frame by replication using the second master mold.

[0031] Further, the fabricating a micro-nano structure, where the deformation material is used as the base layer of the micro-nano structure, includes:

[0032] Coating glue on the surface of a substrate layer to prepare the deformation material, forming the second deformation layer;

[0033] Grow a metasurface thin film on the surface of the second deformed layer, and etch a nano-pillar array on the metasurface thin film;

[0034] Use a lift-off process to peel off the second deformed layer and the nano-pillar array from the substrate layer to obtain the micro-nano structure.

[0035] Furthermore, when fabricating the micro-nano structure, with the deformed material as the base layer, the micro-nano structure includes:

[0036] Coat glue on the surface of the substrate layer to prepare the deformed material to form the second deformed layer;

[0037] Grow a metal material on the surface of the second deformed layer to form a base layer;

[0038] Grow a dielectric on the surface of the base layer to form an insulating layer;

[0039] Grow a metasurface thin film on the surface of the insulating layer, and etch a nano-pillar array on the metasurface thin film;

[0040] Use a lift-off process to peel off the second deformed layer, the base layer, the insulating layer and the nano-pillar array from the substrate layer to obtain the micro-nano structure.

[0041] Furthermore, before filling the deformed material into the rigid frame to form the first deformed layer, the method further includes:

[0042] Simulate and determine the design parameters of the hydrogen sensor, where the design parameters include the thickness and material of each layer of the hydrogen sensor;

[0043] Fabricate a hydrogen sensor based on the design parameters.

[0044] The advantages of the present invention are:

[0045] (1) The process of the hydrogen sensor designed by the present invention for detecting hydrogen concentration is as follows: when the gas-sensitive material absorbs hydrogen, it will deform, and the area of the gas-sensitive layer increases. Since the top of the gas-sensitive layer is designed with a non-deformable top shell, the deformation can only be transmitted downward to the first deformation layer, and then the deformation of the gas-sensitive layer is transmitted to the micro-nano structure by the first deformation layer. The micro-nano structure driven by the first deformation layer to deform will form a periodic change in the internal structure, resulting in a change in light transmittance. By measuring the change in light intensity before and after the deformation of the micro-nano structure, the hydrogen concentration can be quantitatively determined. The present invention designs a deformation transfer structure composed of a rigid frame, a first deformation layer, a gas-sensitive layer, and a top shell. The deformation generated after the gas-sensitive layer absorbs hydrogen accumulates and is transmitted to the micro-nano structure with a smaller area, converting the deformation of the gas-sensitive layer into the deformation of the micro-nano structure, which is equivalent to converting time accumulation into an area quantity. At the same time, deformation will occur on all the areas in contact with hydrogen, realizing the amplification of the change amount of the micro-nano structure, converting the time that needs to be accumulated into the volume advantage of the gas-sensitive layer, and finally achieving a fast response.

[0046] (2) The present invention provides a micro-nano structure as a conversion carrier for H2 concentration signals. When light with a specific wavelength irradiates the hydrogen sensor, it can provide the maximum detection signal through the nano-scale size and periodic change of the micro-nano structure.

[0047] (3) The micro-nano structure set by the present invention is a nano-column array composed of relatively simple metal nano-columns. For the micro-nano processing technology, it can be realized only by imprinting or photolithography after coating. The processing technology is relatively simple and can ensure consistency.

[0048] Additional aspects and advantages of the present invention will be given in part in the following description, will become apparent in part from the following description, or will be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 is a schematic structural diagram of a transmissive hydrogen sensor proposed in Embodiment 1 of the present invention;

[0050] Figure 2 is a schematic diagram of the change in transmittance of the transmissive hydrogen sensor in different hydrogen concentration environments in Embodiment 1 of the present invention;

[0051] Figure 3 is a schematic structural diagram of a reflective hydrogen sensor proposed in Embodiment 2 of the present invention;

[0052] Figure 4 is a schematic diagram of the change in transmittance of the reflective hydrogen sensor before and after introducing hydrogen in Embodiment 2 of the present invention;

[0053] Figure 5 is a schematic diagram of the design process flow of a transmissive hydrogen sensor proposed in Embodiment 3 of the present invention;

[0054] Figure 6 It is a schematic diagram of the design process flow of a reflective hydrogen sensor proposed in the fourth embodiment of the present invention.

[0055] In the figure:

[0056] 11 - Rigid frame 1; 12 - Deformation layer 1; 13 - Gas - sensitive layer 1; 14 - Top shell 1; 15 - Light - transmitting part 1; 16 - Micro - nano structure 1;

[0057] 21 - Rigid frame 2; 22 - Deformation layer 2; 23 - Gas - sensitive layer 2; 24 - Top shell 2; 25 - Light - transmitting part 2; 26 - Micro - nano structure 2;

[0058] 31 - Upper support plate; 32 - Lower support plate; 33 - Connecting plate;

[0059] 41 - Light source; 42 - Light detector;

[0060] 161 - Deformation layer 3; 162 - Nanopillar array 1;

[0061] 261 - Deformation layer 4; 262 - Base layer; 263 - Insulating layer; 264 - Nanopillar array 2. Detailed implementation manners

[0062] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0063] Embodiment 1

[0064] As Figure 1 shown, the first embodiment of the present invention proposes a transmissive hydrogen sensor, including a rigid frame 11. The rigid frame 11 is filled with a deformation material to form a deformation layer 12. A gas - sensitive layer 13 made of a gas - sensitive material and a top shell 14 made of a hard - type material are sequentially arranged on the surface of the deformation layer 12; The rigid frame 11 is reserved with a light - transmitting part 15, and a micro - nano structure 16 is arranged on the surface of the deformation layer 12 at the light - transmitting part 15.

[0065] Among them, the rigid frame 11 includes an upper support plate 31 and a lower support plate 32. Two connecting plates 33 are arranged between the upper support plate 31 and the lower support plate 32 to form a cavity, and the upper support plate 31 is communicated with the cavity; The upper support plate 31 and the cavity are filled with the deformation material to form an I - shape, and the rigid frame can reduce the influence of temperature change on the deformation amount.

[0066] Further, light-transmitting holes are formed at corresponding positions of the two connecting plates 33 to form the first light-transmitting part 15. Among them, the light-transmitting hole formed on one connecting plate 33 is located on the path of the incident light emitted by the light source 41, and a first micro-nano structure 16 is arranged on the surface of the deformation layer 12 corresponding to the light-transmitting hole; a light detector 42 is arranged on the path of the outgoing light of the light-transmitting hole formed on the other connecting plate 33 for detecting the light intensity signal.

[0067] Further, the micro-nano structure includes a third deformation layer 161, which serves as the substrate for the deformation of the metasurface. A nano-column array 162 formed by a metasurface thin film is arranged on the surface of the third deformation layer 161. Among them, the micro-nano structure is fixed on the surface of the first deformation layer 12 by glue coating.

[0068] It should be noted that the material of the metasurface thin film in the transmissive structure is aluminum.

[0069] Specifically, the micro-nano structure designed in this embodiment is an array structure formed by a plurality of identical metal columns, and the metal columns are arranged at a fixed distance from each other, so there is a light transmission intensity value. When there is hydrogen, the gas-sensitive material absorbs it and the area will increase, resulting in deformation, which in turn drives the deformation of the substrate of the metal nano-column array, that is, the third deformation layer 161. The deformation of the third deformation layer 161 changes the distance between the metal nano-columns, thereby changing the transmitted light intensity. The light detector 42 can calculate the hydrogen concentration based on the detected light intensity signal.

[0070] In this embodiment, the micro-nano structure is used as the conversion carrier of the H2 concentration signal. When light of a specific wavelength irradiates the micro-nano structure, the maximum detection signal can be provided through the nano-scale size and periodic change of the micro-nano structure; and the set micro-nano structure is a nano-column array composed of relatively simple metal nano-columns. For the micro-nano processing technology, it can be realized only by imprinting or photolithography after coating, and the processing technology is relatively simple, which can ensure consistency.

[0071] Further, the thickness and material of each layer of the transmissive hydrogen sensor in this embodiment are obtained by pre-modeling and simulating the transmissive sensor. Among them, the gas-sensitive material is palladium-gold alloy (the preparation method of the palladium-gold alloy can be realized by conventional methods, which will not be elaborated in this embodiment). The area of the palladium-gold alloy will increase and deform after absorbing hydrogen; the deformation material is polydimethylsiloxane PDMS, which is used as the transfer medium for the deformation of the gas-sensitive material; the hard material is a hard porous material, specifically, polymethyl methacrylate material PMMA or porous ceramic material that cannot generate deformation can be used, so that hydrogen can enter, but deformation cannot occur; the rigid frame is also made of ceramic material.

[0072] It should be noted that the present embodiment does not limit the specific types of gas-sensitive materials, deformation materials and hard materials. Those skilled in the art may select other materials to manufacture the deformation layer 12, gas-sensitive layer 13 and top shell 14 in the present embodiment according to actual conditions, as long as the rigid frame and the top shell cannot be deformed.

[0073] Furthermore, through simulation, this embodiment determines that the thickness of the deformation layer 12 is 200-400 nanometers, the thickness of the gas-sensitive layer 13 is 20 nanometers, the thickness of the top shell 14 is 300 nanometers, the thickness of the deformation layer 3 161 is 50 nanometers, and the thickness of the metal nanocolumn is 20 nanometers.

[0074] It should be understood that the thickness of each layer of the transmissive hydrogen sensor described in this embodiment is obtained by pre-modeling simulation, and other thickness parameters can also be obtained by simulation based on different material sizes. The deformation layer 12 and the deformation layer 3 161 can be prepared with the same material or the same material, which is not specifically limited in this embodiment.

[0075] It should be noted that the traditional super surface structure is to make the gas-sensitive material into a super surface, so the gas-sensitive material is usually very small in volume, and the deformation after absorbing hydrogen is also very small, and a more sensitive detector is needed to detect the change. The transmission type hydrogen sensor designed in this embodiment is to place the gas-sensitive material externally to form a gas-sensitive layer 13, which can be hundreds of times the volume of the gas-sensitive material of the traditional super surface. When the external gas-sensitive material absorbs hydrogen, it will be deformed. Because the top of the gas-sensitive layer 13 is designed with a top shell that cannot be deformed, the deformation can only be transmitted downward to the deformation layer 12. The material PDMS used in the deformation layer 12 is an easy-to-deform material, which will transfer the deformation of the gas-sensitive layer 13 to the micro-nano structure in the middle of the bracket, thereby driving the deformation layer 3 161 to deform. The micro-nano structure driven to deform by the deformation layer 3 161 will form a periodic change of the internal metal nanocolumn structure, thereby causing a change in light transmittance. By measuring the change in light intensity before and after the micro-nano structure is deformed, the concentration of hydrogen can be quantitatively determined.

[0076] Since the micro-nano structure is more delicate and smaller in size, even smaller deformations can form detectable data, thereby improving the detection sensitivity. However, the sensitivity of the micro-nano structure is also limited. Because it absorbs hydrogen to produce deformation, the volume fraction of hydrogen itself is relatively small, and the deformation that can be caused is also limited. For low-concentration environments, it takes time to accumulate hydrogen from the surface to the inside of the gas-sensitive material, increasing the number of hydrogen combinations, thereby achieving the accumulation of deformation, so that the response time at low hydrogen concentrations will increase.

[0077] In this embodiment, the deeper penetration of hydrogen into the gas-sensitive material is converted into a large-area gas-sensitive material, and due to the increase in the volume of the gas-sensitive material, more hydrogen will be absorbed in the same time, resulting in a greater deformation. Enough deformation can be formed in a short time. Combining with the non-deformable rigid frame, the deformation of the gas-sensitive material can be transmitted to the deformation layer 12, and then to the micro-nano structure substrate in the middle of the rigid frame. Since both the rigid frame and the top shell at the top of the gas-sensitive layer are non-deformable, there is only one position where the deformation can be transmitted, which is the micro-nano structure. Therefore, the distance between the columns of the micro-nano structure will change, and the change in the distance between the metal nano-columns can be detected by light, and the signal of the distance change can be converted into the change of the voltage signal on the photodetector 42, so that it can be detected, making the hydrogen sensor more sensitive and shortening the response time at low hydrogen concentrations. Moreover, the wavelength band used by the photodetector 42 is the signal at the peak of the wave, with the strongest and most sensitive signal.

[0078] Furthermore, in this embodiment, the light source 41 can be a single-wavelength LED, eliminating the need for expensive lasers, resulting in lower costs and energy consumption, and a richer range of usage scenarios.

[0079] It should be noted that the transmittance changes of the transmissive hydrogen sensor in different hydrogen concentration environments in this embodiment are as Figure 2 shown, indicating that different hydrogen concentrations will result in different amounts of hydrogen bound to palladium and different amounts of deformation. Curves 1-6 represent that as the hydrogen concentration increases, the amount of deformation also increases, the period of the metasurface becomes larger, the light transmission amount increases, and the light intensity signal strength increases.

[0080] Embodiment Two

[0081] As Figure 3 shown, the second embodiment of the present invention proposes a reflective hydrogen sensor, which includes a second rigid frame 21. The second rigid frame 21 is filled with a deformable material to form a second deformation layer 22. A second gas-sensitive layer 23 made of a gas-sensitive material and a second top shell 24 made of a hard material are sequentially arranged on the surface of the second deformation layer 22; a second light-transmitting part 25 is reserved in the second rigid frame 21, and a second micro-nano structure 26 is arranged on the surface of the second deformation layer 22 at the position of the second light-transmitting part 25.

[0082] Among them, the second rigid frame 21 includes an upper support plate 31 and a lower support plate 32. Two connecting plates 33 are arranged between the upper support plate 31 and the lower support plate 32 to form a cavity, and the upper support plate 31 communicates with the cavity; the upper support plate 31 and the cavity are filled with the deformable material to form an I-shaped structure.

[0083] Further, a light-transmitting hole is formed in a connection plate 33 to form the second light-transmitting portion 25. Among them, the light-transmitting hole is located on the path of the incident light emitted by the light source 41, and a second micro-nano structure 26 is provided on the surface of the corresponding second deformation layer 22. A light detector 42 is arranged on the path of the outgoing light of the light-transmitting hole for detecting the light intensity signal.

[0084] Further, the second micro-nano structure 26 includes a fourth deformation layer 261, a base layer 262, an insulating layer 263, and a second nano-column array 264 formed by a metasurface thin film arranged in sequence; the base layer 262 is made of a metal material such as silver, the insulating layer 263 is prepared from a dielectric material such as silicon dioxide, and the second nano-column array 264 is prepared from a nickel material.

[0085] It should be noted that since different materials are required for transmission and reflection to achieve the processes of transmission and reflection, the second micro-nano structure 26 designed in this embodiment is different from the first micro-nano structure 16 provided in the first embodiment above, but the strain transfer structures adopted by both are the same.

[0086] Further, the thickness and material of each layer of the reflection-type hydrogen sensor in this embodiment are obtained by pre-modeling and simulating the reflection-type sensor. Among them, the gas-sensitive material is palladium-gold alloy; the deformation material is polydimethylsiloxane PDMS used as the transfer medium for the deformation of the gas-sensitive material; the hard material is a hard porous material, and specifically, polymethyl methacrylate material PMMA or porous ceramic material that cannot generate deformation can be used, so that hydrogen can enter but cannot deform; the rigid frame is also made of ceramic material.

[0087] It should be noted that the specific types of the gas-sensitive material, the deformation material, and the hard material are not limited in this embodiment. Those skilled in the art can select other materials to make the second deformation layer 22, the second gas-sensitive layer 23, and the second top shell 24 in this embodiment according to the actual situation, as long as the rigid frame and the top shell at the top cannot deform.

[0088] Further, through simulation in this embodiment, it is determined that the thickness of the second gas-sensitive layer 23 is 20 nanometers, the thickness of the second top shell 24 is 300 nanometers, the thickness of the fourth deformation layer 261 is 50 nanometers, the thickness of the base layer 262 is 60 nanometers, the thickness of the insulating layer 263 is 200 nanometers, and the thickness of the metal nano-columns is 100 nanometers. Among them, the base layer 262 is made of silver, and the insulating layer 263 is made of silicon dioxide.

[0089] It should be understood that the thickness of each layer of the reflection-type hydrogen sensor in this embodiment is obtained by pre-modeling and simulating, and other thickness parameters can also be obtained by simulating based on different material dimensions. Among them, the transmittance change of the reflection-type hydrogen sensor in this embodiment under different hydrogen concentration environments is as Figure 4As shown, it shows that the increase in hydrogen concentration also leads to an increase in the metasurface period, a decrease in the plasmon resonance absorption of light between the structures, and an increase in the intensity of the reflected light signal.

[0090] It should be understood that the working principle and advantages of the reflective hydrogen sensor described in this embodiment are the same as those of the transmissive hydrogen sensor described in Embodiment 1 above, and will not be elaborated here.

[0091] Embodiment 3

[0092] As Figure 5 shown, this embodiment proposes a design method for a transmissive hydrogen sensor, which specifically includes:

[0093] 1-1) Print and prepare Master Plate 1;

[0094] 1-2) Replica mold to prepare Rigid Frame 1;

[0095] 1-3) Fill with a deformable material (PDMS is used in this embodiment) to form Deformation Layer 1, which serves as a transmission medium for the deformation of the gas-sensitive material;

[0096] 1-4) Evaporate / sputter a gas-sensitive material on the upper surface of the flat deformable material to form a gas-sensitive layer 1 with a thickness of 20 nanometers, which serves as the main substance for hydrogen detection;

[0097] 1-5) Prepare a hard porous material (PMMA or porous ceramic is used in this embodiment) to form a top shell 1 with a thickness of 300 nanometers. This top shell 1 allows hydrogen to enter but does not allow deformation;

[0098] 1-6) Clean the surface of the quartz substrate (the size can be 12 inches);

[0099] 1-7) Coat the quartz surface with glue to prepare a deformable material to form a deformation layer 3 with a thickness of 50 nanometers, which serves as the substrate for the metasurface deformation;

[0100] 1-8) Grow a metasurface thin film with a thickness of 20 nanometers on the surface of deformation layer 3, which serves as a medium for changing the light transmittance;

[0101] 1-9) Use a photomask for photolithography (or imprint template for nanoimprinting) to etch a nano-column array on the metasurface thin film;

[0102] 1-10) Use a lift-off process to peel off deformation layer 3 and the nano-column array from the quartz to obtain Micro-Nano Structure 1;

[0103] 1-11) Use photosensitive glue to fix the micro-nano structure 1 with the deformable material as the substrate to the corresponding position of the light-transmitting part on the rigid frame for fixing the light source and the light detector at the response position.

[0104] Embodiment 4

[0105] As shown Figure 6 in the figure, this embodiment proposes a design method for a reflective hydrogen sensor, which specifically includes:

[0106] 2-1) Printing and preparing master mold two;

[0107] 2-2) Replica molding to prepare rigid frame two;

[0108] 2-3) Filling the rigid frame two with a deformation transfer material (usually PDMS) to form gas-sensitive layer two, which serves as the transfer medium for the deformation of the gas-sensitive material;

[0109] 2-4) Evaporating / sputtering a gas-sensitive material on the surface of the flat deformation layer two to form a gas-sensitive layer two with a thickness of 20 nanometers, which serves as the main substance for hydrogen detection;

[0110] 2-5) Preparing a hard porous material (usually PMMA or porous ceramic) to form a top shell two with a thickness of 300 nanometers, which allows hydrogen to enter but does not deform;

[0111] 2-6) Cleaning the surface of the quartz substrate (with a size of 12 inches);

[0112] 2-7) Coating the quartz surface with glue to prepare a deformation material to form a deformation layer four with a thickness of 50 nanometers, which serves as the substrate for the deformation of the metasurface;

[0113] 2-8) Growing a metasurface metal film on the surface of the deformation layer four to form a base layer with a thickness of 60 nanometers;

[0114] 2-9) Growing a dielectric on the base layer to form an insulating layer with a thickness of 200 nanometers;

[0115] 2-10) Growing a metasurface thin film with a thickness of 100 nanometers on the surface of the insulating layer, which serves as the medium for changing the light transmittance;

[0116] 2-11) Using a photomask for photolithography (or imprint template nanoimprinting) on the metasurface thin film to etch out a nano-pillar array;

[0117] 2-12) Using a lift-off process to peel off the deformation layer four, the base layer, the insulating layer, and the nano-pillar array from the quartz to obtain the micro-nano structure two;

[0118] 2-13) Using a photosensitive glue to fix the micro-nano structure two to the corresponding position of the light-transmitting part of the rigid frame for fixing the light source and the light detector at the response position.

[0119] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0120] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0121] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A hydrogen sensor, characterized in that, It includes a rigid frame, and the rigid frame is filled with a deformable material to form a first deformable layer. A gas-sensitive layer made of a gas-sensitive material and a top shell made of a hard material are sequentially arranged on the surface of the first deformable layer. The rigid frame is reserved with a light-transmitting part, and a micro-nano structure is arranged on the surface of the first deformable layer at the light-transmitting part.

2. The hydrogen sensor according to claim 1, characterized in that, The rigid frame forms an I-shaped structure after being filled with the deformable material.

3. The hydrogen sensor according to claim 1, characterized in that, The deformable material uses polydimethylsiloxane.

4. The hydrogen sensor according to claim 1, characterized in that, The gas-sensitive material uses a palladium-gold alloy.

5. The hydrogen sensor according to claim 1, wherein, The hard material uses a hard porous material.

6. The hydrogen sensor according to claim 1, wherein The rigid frame is prepared by using ceramics.

7. The hydrogen sensor according to claim 1, characterized in that, The rigid frame includes upper and lower support plates. Two connecting plates are arranged between the upper support plate and the lower support plate to form a cavity, and the upper support plate communicates with the cavity. The upper support plate and the cavity are filled with the deformable material to form an I-shaped structure.

8. The hydrogen sensor according to claim 7, wherein, Both of the two connecting plates are provided with light-transmitting holes to form the light-transmitting part, or one of the connecting plates is provided with a light-transmitting hole to form the light-transmitting part.

9. The hydrogen sensor according to claim 1, characterized in that, The micro-nano structure includes a second deformable layer, and a nano-column array formed by a metasurface thin film is arranged on the surface of the second deformable layer.

10. The hydrogen sensor according to claim 1, wherein, The micro-nano structure includes a second deformable layer, a base layer, an insulating layer, and a nano-column array formed by a metasurface thin film arranged in sequence. The base layer is made of a metal material, and the insulating layer is prepared by using a dielectric material.

11. A design method for a hydrogen sensor as described in any one of claims 1-10, characterized in that, It includes: Preparing a rigid frame by using a master mold for replication; Filling a deformable material in the rigid frame to form a first deformable layer; Evaporating or sputtering a gas-sensitive material on the surface of the first deformable layer to form a gas-sensitive layer; Coating a hard material on the gas-sensitive layer to form a top shell; Fabricating a micro-nano structure, and using the deformable material as a base layer for the micro-nano structure; Fixing the micro-nano structure on the surface of the first deformable layer at the light-transmitting part to form a hydrogen sensor.

12. The design method of the hydrogen sensor according to claim 11, characterized in that, The preparing a rigid frame by using a master mold for replication includes: Printing and preparing a first master mold corresponding to a transmissive sensor, and using the first master mold for replication to prepare a first rigid frame; Printing and preparing a second master mold corresponding to a reflective sensor, and using the second master mold for replication to prepare a second rigid frame.

13. The design method of the hydrogen sensor according to claim 12, wherein, The fabricating a micro-nano structure, and using the deformable material as a base layer for the micro-nano structure includes: Coating glue on the surface of a substrate layer to prepare the deformable material to form the second deformable layer; Growing a metasurface thin film on the surface of the second deformable layer, and etching a nano-column array on the metasurface thin film; Using a lift-off process to peel the second deformable layer and the nano-column array from the substrate layer to obtain the micro-nano structure.

14. The design method of the hydrogen sensor according to claim 12, characterized in that, The fabricating a micro-nano structure, and using the deformable material as a base layer for the micro-nano structure includes: Coating glue on the surface of a substrate layer to prepare the deformable material to form the second deformable layer; Growing a metal material on the surface of the second deformable layer to form a base layer; Growing a dielectric on the surface of the base layer to form an insulating layer; Growing a metasurface thin film on the surface of the insulating layer, and etching a nano-column array on the metasurface thin film; Using a lift-off process to peel the second deformable layer, the base layer, the insulating layer, and the nano-column array from the substrate layer to obtain the micro-nano structure.

15. The design method of the hydrogen sensor according to any one of claims 11-14, characterized in that Before filling a deformable material in the rigid frame to form a first deformable layer, the method further includes: Simulating and determining the design parameters of the hydrogen sensor, where the design parameters include the thickness and material of each layer of the hydrogen sensor; Fabricating a hydrogen sensor based on the design parameters.

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