A micro-nano sensing structure and its application

Abstract

The present invention provides a micro-nano sensing structure and its application, which relates to the field of gas detection. Specifically, the micro-nano sensing structure provided by the present invention includes a substrate, a humidity sensitive material and a gas sensitive material, wherein the humidity sensitive material is placed on the surface of the substrate, and the gas sensitive material is placed on the surface of the humidity sensitive material. The micro-nano structure also includes a metal reflective layer and an adhesion layer, wherein the metal reflective layer is bonded to the substrate through the adhesion layer, and the humidity sensitive material is placed on the surface of the metal reflective layer. The micro-nano sensing structure provided by the present invention is a micro-nano sensing structure based on optical principles, which does not generate electric sparks during use, and can effectively avoid the risk of gas explosion caused by traditional sensors. At the same time, the micro-nano sensing structure provided by the present invention also has the advantages of low cost and high integration.

Description

Technical Field

[0001] The present invention relates to the field of gas detection, and in particular to a micro-nano sensing structure and applications thereof. Background Art

[0002] In the underground working environment, there may be a variety of toxic and harmful gases (such as carbon monoxide CO, hydrogen sulfide H2S, etc.) and combustible gases. The mixed gas formed by combustible gases and other combustion-supporting gases often has flammable and explosive properties. Therefore, in the underground working environment and during the production, storage, transportation and use of related combustible gases, it is often necessary to monitor the concentration of combustible gases in real time. Based on this, the application research of combustible gas sensors has received widespread attention. However, at present, common combustible gas sensors are generally electrochemical sensors. Such sensors are extremely susceptible to electromagnetic interference when in use. At the same time, electrochemical sensors may generate electric sparks during use, which will further increase the risk of combustible gas explosion.

[0003] In addition, humidity is also an important factor affecting the safety of underground operations. High humidity may cause equipment failure or discomfort to personnel. Therefore, gas humidity is an important indicator for judging the storage status of related gases. However, most of these sensors are still electrochemical sensors, and in actual production and use, almost all sensors only support a single detection indicator of humidity or gas content. Multiple sensors need to be used in complex environments, which increases costs and has a low degree of integration. In addition, if the gas concentration and humidity detection sensors are integrated into one, the detection accuracy of the related sensors will be limited due to changes in the detection samples. Therefore, how to improve the detection accuracy of integrated sensors is also an urgent problem to be solved. Summary of the invention

[0004] The object of the present invention is to provide a gas sensing structure which does not generate electric sparks and supports multifunctional detection.

[0005] To achieve the above objectives, the first aspect of the present invention provides a micro-nano sensing structure, which is a penetrating micro-nano sensing structure, specifically including a substrate, a humidity sensitive material and a gas sensitive material, wherein the humidity sensitive material is placed on the surface of the substrate, and the gas sensitive material is placed on the surface of the humidity sensitive material.

[0006] When visible light is incident on the penetrating micro-nano sensing structure described in the present invention from a specific direction, two valley-shaped bands regarding gas content and humidity will appear in the spectrum lines of the transmission spectrum of the penetrating micro-nano structure. When the gas sensitive material reacts with the gas, its refractive index and transmittance will change, thereby changing the center wavelength position of the valley-shaped band regarding gas content in the spectrum line. When the humidity sensitive material reacts with water, it will absorb water and expand, and its refractive index and transmittance will also change, thereby changing the center wavelength position of the valley-shaped band regarding humidity in the spectrum line. Based on this, the penetrating micro-nano sensing structure provided by the present invention can determine the gas concentration according to the center wavelength position of the gas content valley-shaped band of the penetrating spectrum line when in use, and determine the ambient humidity by the center wavelength position of the humidity valley-shaped band.

[0007] Preferably, the micro-nano sensing structure may also be a reflective micro-nano sensing structure, which, based on the penetrating micro-nano sensing structure, further includes a metal reflective layer and an adhesion layer, wherein the metal reflective layer is bonded to the substrate via the adhesion layer, and the humidity sensitive material is placed on the surface of the metal reflective layer.

[0008] When visible light is incident on the reflective micro-nano sensing structure described in the present invention from a specific direction, two valley-shaped bands regarding gas content and humidity will appear in the spectrum lines of the reflective spectrum of the reflective micro-nano sensing structure. When the gas sensitive material reacts with the gas, its refractive index will change, thereby changing the center wavelength of one of the valley-shaped bands of the spectrum line. When the humidity sensitive material reacts with water, it will absorb water and expand, and its refractive index will also change, thereby changing the depth of the valley-shaped band regarding humidity in the spectrum line. Based on this, the reflective micro-nano sensing structure provided by the present invention can determine the gas concentration according to the depth of the gas content valley-shaped band of the reflective spectrum line when in use, and determine the ambient humidity by the center wavelength of the humidity valley-shaped band of the spectrum line.

[0009] Preferably, the moisture sensitive material has a morphology selected from any one of a grating structure, a waveguide structure and a grating-waveguide composite structure.

[0010] Preferably, the gas sensitive material has a form selected from any one of a grating structure, a square array and a disk array.

[0011] Preferably, the humidity sensitive material is made of any material having water absorption properties.

[0012] Preferably, the gas sensitive material is made of metal, alloy or metal compound that can react with gas.

[0013] Preferably, the substrate is a rigid substrate or a flexible substrate.

[0014] Preferably, the metal reflective layer is made of a metal material with a reflectivity greater than 70%.

[0015] Preferably, the adhesion layer is any one of titanium, chromium, nickel and polymer glue.

[0016] Furthermore, the second aspect of the present invention provides an application of the micro-nano sensing structure described in the first aspect, and the application includes using the aforementioned micro-nano sensing structure for humidity and / or concentration detection of gas.

[0017] Furthermore, the third aspect of the present invention provides a sensor, which specifically includes the micro-nano sensing structure as described in the first aspect.

[0018] The micro-nano sensing structure provided by the present invention can detect humidity and various gases separately or simultaneously by optical methods, and the detection processes do not affect each other. The reflective and transmissive structures are characterized by the changes in reflected light and transmitted light signals respectively, and various types of sensors can be constructed based on this.

[0019] Compared with the prior art, the present invention has the following beneficial effects: the sensors for detecting gas concentration and humidity in the prior art are usually electrochemical sensors, which are prone to sparks and have the risk of gas explosion. The micro-nano sensing structure provided by the present invention is a micro-nano sensing structure based on optical principles. The gas concentration and / or humidity data are obtained by reading the penetration spectrum or reflection spectrum of the micro-nano sensing structure. No electric sparks will be generated during the use of the micro-nano sensing structure, which can effectively avoid the risk of gas combustion and explosion. At the same time, the sensors in the prior art can only detect a single indicator, and multiple sensors need to be used in complex scenarios. The micro-nano sensing structure provided by the present invention integrates gas sensitive materials and humidity sensitive materials on the substrate, and a single device can be used to detect both gas concentration and humidity, thereby reducing costs and improving integration. While improving the integration of the micro-nano sensing structure, the present invention can ensure the accuracy of the micro-nano sensing structure during detection and improve anti-interference ability because the data of gas concentration and humidity are expressed through different spectral lines. In addition, when using the micro-nano sensing structure provided by the present invention, relevant data can be quickly and accurately obtained based on the valleys of gas content or humidity in the reflection spectrum or transmission spectrum of the micro-nano sensing structure, which has the advantages of simple operation and high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a transmission type micro-nano sensing structure in a specific embodiment of the present invention;

[0021] Figure 2 It is a structural schematic diagram of a reflective micro-nano sensing structure in a specific implementation manner of the present invention;

[0022] Figure 3 A schematic diagram of a light-incident transmission type micro-nano sensing structure in a specific embodiment of the present invention;

[0023] Figure 4 It is the spectrum line diagram and field distribution diagram of the micro-nano sensing structure in Example 1 of the specific implementation mode of the present invention when the nitrogen concentration is 0%;

[0024] Figure 5 This is a graph showing the variation of the spectral lines of the micro-nano sensing structure under different nitrogen concentrations in Example 1 of the specific implementation mode of the present invention;

[0025] Figure 6 This is a statistical diagram of the central wavelength deviation of the micro-nano sensing structure under different humidity conditions in Example 1 of the specific implementation mode of the present invention;

[0026] Figure 7 A schematic diagram of a visible light incident reflective micro-nano structure in a specific embodiment of the present invention;

[0027] Figure 8 It is a spectrum line diagram and field distribution diagram of the reflective micro-nano sensing structure in Example 2 of the specific implementation mode of the present invention when detecting a hydrogen concentration of 0%;

[0028] Fig. 9 This is a schematic diagram of the change of the spectral line of the micro-nano sensing structure in the hydrogen concentration range of 0% to 2% in Example 2 of the specific implementation mode of the present invention;

[0029] Fig.10 This is a statistical diagram of the central wavelength deviation of the micro-nano sensing structure under different humidity conditions in Example 2 of the specific implementation manner of the present invention.

[0030] Description of reference numerals:

[0031] 1. Substrate; 2. Adhesion layer; 3. Metal reflective layer; 4. Humidity sensitive material; 5. Gas sensitive material. DETAILED DESCRIPTION

[0032] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below. It should be noted that the following embodiments are only used to illustrate the implementation method and typical parameters of the present invention, and are not used to limit the parameter range described in the present invention. Reasonable changes derived therefrom are still within the scope of protection of the claims of the present invention.

[0033] It should be noted that the endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in this article.

[0034] Unless otherwise defined, all terms, symbols and other scientific terms used herein are intended to have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. In some cases, terms with conventionally understood meanings are defined herein for the purpose of clarification or ease of reference, and such definitions herein should not be construed as indicating significant differences from conventional understandings in the art. The technical methods described or cited herein are generally well understood by those skilled in the art and are adopted by conventional methods. Unless otherwise stated, the use of commercially available instruments is carried out in accordance with the protocols and parameters given by the manufacturer.

[0035] As described in the background technology, since the current gas concentration and humidity detection sensors are often electrochemical sensors that are prone to generate electric sparks and cause combustible gas explosions, and the gas sensors provided by the prior art only support the separate detection of humidity or concentration, in order to solve the above problems, the specific embodiment of the present invention provides a new optical principle micro-nano sensing structure that can be used for separate or simultaneous detection of gas concentration and humidity. The micro-nano sensing structure is a reflective micro-nano sensing structure ( Figure 2 ) or transmissive micro-nano sensing structure ( Figure 1 ).

[0036] See also Figure 1 The transmissive micro-nano sensing structure includes a substrate 1, a humidity sensitive material 4 and a gas sensitive material 5, wherein the humidity sensitive material 4 is placed on the surface of the substrate 1, and the gas sensitive material 5 is placed on the surface of the humidity sensitive material 4.

[0037] See also Figure 3 When the visible light source is incident on the penetrating micro-nano sensing structure provided in the above embodiment, the transmission spectrum line of the penetrating micro-nano sensing structure will appear as follows: Figure 4 The four valley shapes shown in the figure have field distribution diagrams corresponding to each valley shape. Figure 4 As shown in the field distribution diagram of the C valley corresponding to the central wavelength, it can be seen that the field intensity of the gas sensitive material is much higher than that of other parts, indicating that the energy is mainly concentrated in the gas sensitive material part. If the parameters of the gas sensitive material change, the impact on the C valley is most obvious. Therefore, it can be determined Figure 4 The C valley in the figure is the valley shape related to the gas concentration. As the gas concentration changes, the refractive index of the gas sensitive material 5 will change, and the position of the corresponding central wavelength of the C valley will also change. The concentration of the relevant gas can be read according to the position of the central wavelength of the C valley. In the field distribution diagram corresponding to the central wavelength of the D valley, it can be seen that the field intensity of the humidity sensitive material is much higher than that of other parts, indicating that the energy is mainly concentrated in the humidity sensitive material part at this time. If the parameters of the humidity sensitive material change, the impact on the D valley is most obvious. Therefore, Figure 4The D valley in the diagram is the valley shape related to humidity. As the water content changes, the volume of the humidity sensitive material will also change, and the transmittance will also change, thereby changing the central wavelength position of the D valley. The humidity data can be read based on the central wavelength position of the D valley. Figure 4 It can be seen from the field distribution diagram of the central wavelength of the F valley in that the energy on the micro-nano structure is also strong on the gas sensitive material. However, if the data of the F valley is selected as the valley-shaped band about the gas concentration, since the F valley is closer to the D valley than the C valley, the stability of its data is weaker than that of the C valley. Therefore, in this embodiment, the F valley is not used as a selection indicator. Figure 4 It can be seen from the field distribution diagram of the G valley that the energy on the micro-nano structure is more distributed on the substrate than the D valley, and its sensitivity is lower than that of the D valley. Therefore, it is not used as a selection indicator in this embodiment. In the above embodiment, the detection indicators of gas concentration and humidity are displayed through the transmission spectrum of the micro-nano sensing structure rather than directly through the light emission position. Therefore, no matter the incident light is incident from the substrate at any angle or from the gas sensitive material at any angle, the detection task can be completed.

[0038] See also Figure 2 The reflective micro-nano sensing structure, based on the transmissive micro-nano structure, further includes a metal reflective layer 3 and an adhesion layer 2, wherein the metal reflective layer 3 is bonded to the substrate 1 through the adhesion layer 2, the humidity sensitive material 4 is prepared on the surface of the metal reflective layer 3, and the gas sensitive material 5 is placed on the humidity sensitive material 4.

[0039] See also Figure 7 When the incident angle of the visible light source is incident on the reflective micro-nano sensor structure provided by the above embodiment at a specific angle, the reflection spectrum line of the reflective micro-nano sensor structure appears as follows: Figure 8 The three valley shapes shown in the figure have field distribution diagrams corresponding to each valley shape. Figure 8 As shown in the field distribution diagram of the central wavelength corresponding to valley A, it can be seen that the field intensity of the gas sensitive material is much higher than that of other parts, indicating that the energy is mainly concentrated in the gas sensitive material part. If the parameters of the gas sensitive material change, the impact on valley A is the most obvious. Therefore, it can be determined Figure 8 The A valley in the figure is the valley shape related to the gas concentration. As the gas concentration changes, the refractive index of the gas sensitive material 5 will change, and the corresponding depth of the A valley will also change. The concentration of the relevant gas can be read according to the depth of the A valley. In the field distribution diagram corresponding to the central wavelength of the B valley, it can be seen that the field intensity of the humidity sensitive material is much higher than that of other parts, indicating that the energy is mainly concentrated in the humidity sensitive material part at this time. If the parameters of the humidity sensitive material change, the impact on the B valley is the most obvious. Therefore, Figure 8The B valley in the diagram is the valley shape related to humidity. As the water content changes, the volume of the humidity-sensitive material will change, and the refractive index will also change, which will affect the central wavelength position of the B valley. The humidity data can be read based on the central wavelength position of the B valley. Figure 8 It can be seen from the field distribution diagram of the central wavelength of the E valley that the energy distribution on the micro-nano structure is not concentrated enough and is not mainly concentrated on the humidity sensitive material or the gas sensitive material. Therefore, the E valley is interference data and is not used as a selection indicator.

[0040] In the above embodiment, the form of the humidity sensitive material 4 is selected from any one of a grating structure, a waveguide structure and a grating-waveguide composite structure.

[0041] In the above embodiment, the shape of the gas sensitive material 5 is selected from any one of a grating structure, a square array and a disk array.

[0042] In the above embodiment, the humidity sensitive material 4 is made of any material having water absorption performance.

[0043] More specifically, the material of the humidity sensitive material 4 can be selected from any one of high molecular polymer, silica gel, fiber, ceramic or graphene.

[0044] In the above embodiment, the gas sensitive material 5 is made of metal, alloy or metal compound that can react with a specific gas.

[0045] More specifically, the material of the gas sensitive material 5 can be selected from any one of metal palladium, metal magnesium, metal yttrium, nickel-manganese alloy, tin dioxide, and zinc oxide.

[0046] More specifically, the thickness of the gas sensitive material 5 should be greater than 5 nm.

[0047] In the above embodiments, the substrate 1 is a rigid substrate or a flexible substrate.

[0048] More specifically, the material of the substrate 1 can be selected from any one of silicon, silicon dioxide, PU, ​​and PDMS.

[0049] In the above embodiment, the metal reflective layer 3 is made of a metal material with a reflectivity greater than 70%.

[0050] More specifically, the material of the metal reflective layer 3 can be selected from any one of gold, silver, copper and aluminum.

[0051] More specifically, the thickness of the metal reflective layer 3 should be greater than 100 nm.

[0052] In the above embodiment, the adhesion layer 2 is a titanium adhesion layer.

[0053] The technical solution of the present invention is further described below through specific embodiments. Example 1

[0054] The target gas detected in this embodiment is nitrogen.

[0055] The micro-nano sensing structure provided in this embodiment is a transmissive micro-nano sensing structure, wherein the substrate material is silicon dioxide, the humidity sensitive material is polyvinyl alcohol with a grating structure, the grating bar has a thickness of 260nm and a width of 180nm, and the spacing between two adjacent grating bars is 110nm, and the gas sensitive material is a metal aluminum bar with a width of 60nm and a thickness of 5nm.

[0056] When the above-mentioned micro-nano sensing structure is placed in an environment with a nitrogen concentration of 0%, visible light is vertically irradiated into the micro-nano sensing structure. The spectrum line diagram of the relevant spectrum is as follows: Figure 4 shown.

[0057] At high temperatures, aluminum metal reacts with nitrogen to form aluminum nitride, and the position of the center wavelength of the relevant valley line is used to characterize nitrogen detection. When aluminum metal reacts completely with nitrogen, the center wavelength of the relevant valley line in the transmission spectrum of the micro-nano structure will appear as follows: Figure 5 movement.

[0058] Under different humidity conditions, the central wavelength of the humidity-related spectrum of the above micro-nano sensing structure was measured. The relevant results are as follows: Figure 6 As shown, it can be seen that the higher the humidity in the gas environment, the more water molecules are absorbed by the polyvinyl alcohol structure, the greater the volume expansion and transmittance change, and the greater the change in the transmission spectrum. Example 2

[0059] The target gas detected in this embodiment is hydrogen.

[0060] The micro-nano sensing structure provided in this embodiment is a reflective micro-nano sensing structure, wherein the substrate material is silicon, the metal reflective layer material is a gold film with a thickness of 120nm, the adhesion layer between silicon and the gold film is titanium, the humidity sensitive material material is polyvinyl alcohol of a grating structure, the grating strip is 250nm thick, the width is 150nm, and the spacing between two adjacent grating strips is 200nm. The material of the gas sensitive material 5 is a metal palladium strip with a width of 60nm and a thickness of 5nm.

[0061] When the above-mentioned micro-nano sensing structure is placed in an environment with a hydrogen concentration of 0%, visible light is irradiated into the micro-nano sensing structure at an incident angle of 30°. The spectrum line diagram of the relevant spectrum is as follows: Fig. 9 As shown in the Pd line.

[0062] When the above-mentioned micro-nano sensing structure is placed in an environment with a hydrogen concentration of 2%, visible light is irradiated into the micro-nano sensing structure at an incident angle of 30°. The palladium metal is completely hydrogenated to palladium hydride, and the refractive index changes significantly, thereby significantly changing the spectrum lines. The spectrum lines of the relevant spectrum are shown in the figure below: Fig. 9 As shown in the PdH line.

[0063] like Fig. 9 As shown, the change of hydrogen concentration from 0% to 2% can be Fig. 9 The change in valley depth of the shaded part in the graph shows that the change in the depth of the valley representing the hydrogen concentration will not affect the central wavelength position of the valley representing the humidity.

[0064] The central wavelength of the B valley of the above micro-nano sensing structure was measured at different humidity levels. The relevant results are as follows: Fig.10 As shown, it can be seen that the higher the humidity in the gas environment, the more water molecules are absorbed by the polyvinyl alcohol structure, the greater the volume expansion and refractive index change, and the greater the change in the reflectance spectrum.

[0065] In the production, storage, transportation, and use of gases, due to differences in gas concentrations, such as hydrogen at around 4% and carbon four in the range of 10% to 80%, explosions are prone to occur. The electric sparks generated by traditional electrochemical sensors greatly increase the risk of gas explosion. The micro-nano sensing structure provided in the specific embodiment of the present invention is an optical principle, does not generate electric sparks, and greatly improves safety. At the same time, the micro-nano sensing structure provided in the specific embodiment of the present invention integrates humidity sensing materials and gas sensing materials on the same micro-nano structure, so that the micro-nano sensing structure has the advantage of dual-function detection of gas concentration and humidity. In summary, the micro-nano sensing structure provided in the specific embodiment of the present invention has the potential to become a dual-function detection sensor for gas concentration and humidity.

[0066] In the description of the present invention, it should be noted that the terms "left", "right", "inside", "outside", "front", "back", "head", "tail", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the inventive product is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0067] Although the disclosure is disclosed as above, the protection scope of the disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the disclosure, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A micro-nano sensing structure, characterized in that: The micro-nano sensing structure is a penetrating micro-nano sensing structure or a reflective micro-nano sensing structure, wherein: The penetrating micro-nano sensing structure comprises a substrate (1), a humidity sensitive material (4) and a gas sensitive material (5); the humidity sensitive material (4) is placed on the surface of the substrate (1), and the gas sensitive material (5) is placed on the surface of the humidity sensitive material (4); The reflective micro-nano sensing structure comprises a substrate (1), an adhesion layer (2), a metal reflective layer (3), a humidity sensitive material (4) and a gas sensitive material (5); the metal reflective layer (3) is bonded to the substrate (1) via the adhesion layer (2); the humidity sensitive material (4) is disposed on the surface of the metal reflective layer (3); and the gas sensitive material (5) is disposed on the surface of the humidity sensitive material (4). The humidity sensitive material is made of polyvinyl alcohol with a grating structure, the thickness of the grating strips is 250-260 nm, the width is 150-180 nm, and the spacing between two adjacent grating strips is 110-200 nm; The gas sensitive material is selected from any one of metal palladium, metal aluminum, metal magnesium, metal yttrium, nickel-manganese alloy, tin dioxide, and zinc oxide. The gas sensitive material is in the form of a strip with a width of 60 nm and a thickness of 5 nm.

2. The micro-nano sensing structure according to claim 1, characterized in that: The material of the metal reflective layer (3) is a metal material with a reflectivity greater than 70%.

3. The micro-nano sensing structure according to claim 1, characterized in that: The material of the adhesion layer (2) is any one of titanium, chromium, nickel, and polymer glue.

4. An application of the micro-nano sensing structure according to any one of claims 1 to 3, characterized in that: The micro-nano sensing structure is used for detecting the humidity and / or concentration of gas.

5. A sensor, characterized in that: It comprises the micro-nano sensing structure as described in any one of claims 1 to 3.

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