Metasurface optical hydrogen sensor and optical device

Abstract

The utility model discloses a metasurface optical type hydrogen sensor and an optical device, the metasurface optical type hydrogen sensor comprises a metasurface micro-nano structure, a gas sensitive material is evaporated on the surface of the metasurface micro-nano structure, the metasurface micro-nano structure is a nanorod array structure, and nanorods are arranged at fixed intervals; different hydrogen concentrations can be measured by combining the hydrogen sensor designed by the utility model with a simple optical system, and compared with a traditional electrochemical sensor and a traditional optical fiber sensor, the hydrogen sensor is simpler in structure, lower in cost, free of sparks in use and easy to popularize and apply on a large scale.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of super surface optical hydrogen sensors and optical devices of optical type. BACKGROUND

[0002] Hydrogen is a major industrial raw material, and is also the most important industrial gas and special gas, and has a wide range of applications in petrochemical, metallurgical, semiconductor and power industries. Compared with conventional gases, hydrogen has many properties that are not conducive to safety: hydrogen has a wider explosion range in air (4% to 75% vol), a lower ignition energy (0.019 mJ), is more easily leaked, and has a higher flame propagation speed. Therefore, hydrogen leakage and explosion are one of the important causes of safety accidents, and it is necessary to detect the hydrogen concentration in the hydrogen use environment and monitor the leakage thereof.

[0003] Hydrogen sensors are special sensors for hydrogen concentration measurement and hydrogen leakage monitoring. In traditional solutions, electrochemical and catalytic combustion type hydrogen sensors have a relatively high market share. For example, the patent application document with publication number CN117388330A mentions a palladium-chromium alloy film hydrogen sensor that uses a hydrogen measurement unit based on a Wheatstone bridge structure, which eliminates measurement errors caused by temperature fluctuations and increases the stability of the sensor. However, considering the high flammability of hydrogen, the electrical sparks that may occur in electrochemical hydrogen sensors increase the safety risk, and cannot fully meet the application scenarios of the current new energy industry.

[0004] Optical hydrogen sensors obtain information through changes in light signal intensity, require less energy, and do not produce electrical sparks during testing, providing a high safety factor. For example, the optical fiber hydrogen sensor mentioned in the patent application document CN117630694A has the advantages of intrinsic safety, high temperature and pressure resistance, and electromagnetic interference resistance. Moreover, due to its high sensitivity and measurement accuracy, it can achieve real-time response characteristics. However, the structure of this optical fiber hydrogen sensor is relatively complex, and the cost is higher. The optical hydrogen sensor with gold-palladium nanostructure mentioned in the patent application document CN104749101A has high sensitivity and can detect extremely low concentrations. However, when depositing the gold-palladium nanostructure onto the transparent base, the array distribution is relatively random, and the palladium film thickness is not certain. Moreover, this nanostructure requires a high-precision spectrometer to detect hydrogen concentration, which is costly and time-consuming. The optical fiber hydrogen sensor mentioned in the patent application document CN110389122A uses a metamaterial coupling method, which requires controlling the correspondence between the transmission coefficient and the incident angle. When the incident light wavelength is 550 nanometers, the resonance angle of the metamaterial is 22°. The metamaterial is prepared on the optical fiber end face with a 22° inclination. Under the condition that the incident light wavelength is 550 nanometers, the metamaterial will resonate and couple with the incident light, forming a strong local light field on its surface, which will excite the fluorescent nanomaterial and produce strong fluorescence. The fluorescence does not resonate and couple with the metamaterial, and can be well transmitted through the metamaterial and coupled into the optical fiber, and then detected. Therefore, this scheme is essentially a reflective hydrogen sensor, and it is difficult to control the correspondence between the transmission coefficient and the incident angle. Moreover, the relationship between the optical fiber hydrogen sensor and the hydrogen concentration is not mentioned. In addition, this scheme requires the use of lasers, optical fiber structures, and fluorescent materials, which increases the production cost. Practical new type content

[0005] The technical problem to be solved by the present utility model lies in how to provide an optical hydrogen sensor with a simple structure and reduce the production cost of the hydrogen sensor.

[0006] The present utility model solves the above technical problems through the following technical means:

[0007] An optical hydrogen sensor with a metasurface is proposed, which includes a metasurface micro-nano structure. The surface of the metasurface micro-nano structure is coated with a gas-sensitive material. The metasurface micro-nano structure is a nano-pillar array structure, and each nano-pillar is arranged at a fixed distance.

[0008] Further, the gas-sensitive material is a palladium-gold alloy.

[0009] Further, the surface of the metasurface micro-nano structure is uniformly coated with a palladium-gold alloy to form a palladium-gold alloy film.

[0010] Further, the size of the nanorod and the size of the palladium-gold alloy film are determined by simulation in advance.

[0011] Further, the hydrogen sensor is located on the path of the light emitted by the LED light source, and a diode is arranged on the path of the emitted light.

[0012] In addition, the utility model provides an optical device, including the super surface optical type hydrogen sensor as described above.

[0013] The utility model has the advantages of:

[0014] (1) the utility model discloses that gas sensitive material is evaporated on the surface of super surface micro-nano structure, forms hydrogen sensor, and the super surface micro-nano structure is nanorod array structure, because hydrogen gas can react with gas sensitive material, causes the refractive index of this gas sensitive material to change, and then causes the light signal after hydrogen sensor to change, just needs to adopt some low -cost component and spare to detect the change of light signal, can measure different hydrogen concentration.

[0015] (2) the hydrogen sensor designed by the utility model combines the optical system and adopts specific material to solve the problem that traditional characteristic spectrum method (NDIR) cannot be applied to hydrogen detection, and compared with traditional electrochemical sensor and traditional optical fiber type sensor, the structure is simpler, and the cost is lower, and in use, will not produce spark, and is easy to mass popularization and application.

[0016] The additional aspects and advantages of the utility model will be partly given in the following description, partly will become obvious from the following description, or be understood by the practice of the utility model. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is the schematic diagram of super surface micro-nano structure under SEM in an embodiment of the utility model;

[0018] Figure 2 It is the schematic diagram of test light path principle in an embodiment of the utility model;

[0019] Figure 3 It is the schematic diagram of different hydrogen concentration test result in an embodiment of the utility model. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described in combination with the embodiments of the utility model below. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.

[0021] As Figure 1 shown, an embodiment of the utility model provides a kind of super surface optical hydrogen sensor, including super surface micro-nano structure, the super surface micro-nano structure surface evaporation gas sensitive material, the super surface micro-nano structure is nano column array structure, each nano column is arranged with fixed distance spacing.

[0022] Specifically, the embodiment is determined by simulation and experimental verification that the super surface micro-nano structure adopts nano column array structure, and is processed using traditional semiconductor processing technology, such as nano-imprint lithography (NIL) technology, to prepare super surface micro-nano structure, and the nano column structure at each position is completely consistent;And after processing is completed, using evaporation technology, gas sensitive material is evaporated on the surface of super surface micro-nano structure, to form super surface optical hydrogen sensor. Since hydrogen will react with gas sensitive material, the refractive index of the gas sensitive material changes, and the light signal changes after passing through the hydrogen sensor, so that different hydrogen concentrations can be measured by detecting the change of light signal using some low-cost components.

[0023] Super surface optics is an artificial optical material composed of subwavelength microstructures, which can realize precise control of phase, amplitude, polarization and wavefront of light waves. The development of super surface technology has brought a series of revolutionary progress in the field of optics, including high-efficiency optical elements, super-compact optical systems and new optoelectronic devices. The embodiment is finally determined that the super surface structure is column structure by simulation and experimental test, and the result observed under SEM in local area is as shown in Figure 1 .

[0024] As a further preferred technical solution, the gas sensitive material adopts palladium-gold alloy.

[0025] The embodiment evaporates gold and palladium in a certain proportion on the surface of super surface micro-nano structure uniformly to form super surface hydrogen sensor chip

[0026] It should be noted that, since the reaction of pure palladium with high concentration of hydrogen may cause hydrogen embrittlement phenomenon, which will cause the stability of the chip to be poor, and the service life will also be reduced accordingly, forming palladium alloy with other metals in a certain proportion can effectively solve this phenomenon, the higher the surface area of palladium, the better the hydrogen absorption performance, but the super surface effect generated should also be considered.

[0027] As a further preferred technical solution, the size of the nanorod and the size of the palladium-gold alloy film are determined in advance through simulation.

[0028] As a further preferred technical solution, the hydrogen sensor is located on the path of the light emitted by the LED light source, and a diode is arranged on the path of the outgoing light.

[0029] Specifically, in the operation of the previous optical hydrogen sensor, the response curve of different hydrogen concentrations is usually realized by analyzing the spectral characteristics of the spectrometer, which has high manufacturing cost and requires a long detection time. The embodiment determines the super surface micro-nano structure as a nanorod array through modeling simulation, and by analyzing the light signal change rate after different concentrations of hydrogen pass into the sensor, the hydrogen concentration information can be obtained, so the corresponding detection light path can be simplified, as shown in Figure 2 The detection light path includes an LED light source and a diode PD, the LED emits light of a specific wavelength to irradiate the surface of the super surface optical hydrogen sensor chip, and the PD receives the light signal. This light path can measure different hydrogen concentrations by receiving the change of the light signal of the PD under single wavelength irradiation. Therefore, the light path structure is simple and the cost is low.

[0030] Specifically, when there is no hydrogen, the AD value of the recording module in the normal environment is recorded as the initial AD value. In the hydrogen concentration range of 3000-40000ppm, several concentrations are selected to pass into the module. Since hydrogen will react with the palladium-gold alloy film on the surface of the super surface structure, the irradiated chip surface structure will change, and then the light signal after passing through the chip will change. The PD can obtain the response AD value change, and the test results are as shown in Figure 3 From the test results, it can be seen that after different concentrations of hydrogen pass into the module, not only the change rate of the AD value is different, the higher the concentration, the faster the change rate, but also the saturation value of the AD value is different, the higher the concentration, the greater the change.

[0031] It should be noted that in the past measurement, hydrogen gas is usually required to react completely with the structure before measurement, and in the present embodiment, by analyzing the light intensity change rate after different concentrations of hydrogen gas are introduced into the sensor chip, the concentration information can be obtained during the reaction process, and secondly, the time for obtaining information can be set, and the measurement can be performed in a short time; if it has been saturated within the specified time, then the signal change amount at the time of complete reaction can be used for further judgment, which serves as a double guarantee.

[0032] Therefore, the present embodiment utilizes the metasurface optical technology, and the strong specific reversible reaction of hydrogen gas and palladium-gold alloy material to produce physical quantity changes, and the optical signal is amplified and detected to characterize the hydrogen gas concentration.

[0033] In addition, another embodiment of the present application also provides an optical device, which comprises the metasurface optical hydrogen sensor according to the first embodiment.

[0034] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the description of the present application, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0035] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one feature. In the description of the present application, the meaning of "multiple" is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0036] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and cannot be understood as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A metasurface optical hydrogen sensor, characterized in that, It includes metasurface micro / nanostructures, on which gas-sensitive materials are vapor-deposited. The metasurface micro / nanostructures are nanopillar arrays, with each nanopillar arranged at a fixed distance from the others.

2. The metasurface optical hydrogen sensor as described in claim 1, characterized in that, The gas-sensitive material is a palladium alloy.

3. The metasurface optical hydrogen sensor as described in claim 1, characterized in that, The surface of the metasurface micro / nano structure is uniformly vapor-deposited with palladium-gold alloy to form a palladium-gold alloy film.

4. The metasurface optical hydrogen sensor as described in claim 3, characterized in that, The dimensions of the nanopillars and the palladium alloy film were determined in advance through simulation.

5. The metasurface optical hydrogen sensor as described in claim 1, characterized in that, The hydrogen sensor is located in the path of the light emitted by the LED light source, and diodes are arranged in the path of the emitted light.

6. An optical device, characterized in that, Including the metasurface optical hydrogen sensor as described in any one of claims 1-5.

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