Silver nanopore-particle co-intercalation array, and preparation method and application thereof

Abstract

The present application relates to the field of micro-nano structure, and provide a kind of silver nanopore-particle co-embedded array and its preparation method and application, the diameter of the silver nanopore is about 250-350nm, and about 0.6 μm deep.The present application can perfectly avoid the problem of plugging and mutual interference between units, and silver nanopore is independent of each other, avoid the problem of mutual interference between units, the silver nanopore-particle co-embedded array structure designed inherits the good signal reproducibility foundation of ordered substrate, and increases chemical adsorption site by silver nanoparticle, realizes trace detection with super-sensitivity.

Description

Technical Field

[0001] This invention belongs to the field of micro-nano structures and relates to a silver nanopore-particle co-embedded array, its preparation method and application. Background Technology

[0002] Micro-nano structures refer to material structures or components with scales ranging from micrometers (μm) to nanometers (nm). They typically exhibit unique physical, chemical, and mechanical properties that differ from the macroscopic world. Micro-nano technology, as an important component of modern science and technology, involves the design, fabrication, manipulation, and application of materials at the micrometer and nanometer scales. Micro-nano technology has wide applications in many fields, particularly in electronics, energy, medicine, environment, and materials science. Significant breakthroughs have been achieved in micro-nano structures over the past few decades, especially in materials, electronics, energy, and biomedicine. With the continuous development of new technologies, micro-nano structures will have a profound impact on a wider range of fields, driving further advancements in science and technology.

[0003] SERS is a technique that uses the Raman scattering effect (the scattering that occurs when molecules interact with light) to detect substances. Raman scattering refers to the phenomenon where, when light shines on molecules, the molecules scatter the light, and the frequency of the scattered light undergoes a slight change. This change is closely related to information such as the vibrational modes, chemical composition, and structure of the molecules. However, traditional Raman scattering signals are very weak and often difficult to detect. Therefore, enhancing the Raman scattering signal is an important issue. Summary of the Invention

[0004] This invention enhances Raman scattering signals by preparing nested microsurface structures.

[0005] Surface-enhanced Raman scattering (SERS) technology significantly enhances the Raman signal by utilizing the surface effect of nanomaterials, thereby greatly improving detection sensitivity.

[0006] Due to their surface effects, micro- and nanostructures typically exhibit greater reactivity and stronger optical properties than bulk materials. Micro- and nanostructures can significantly enhance Raman scattering signals; this effect is known as localized surface plasmon resonance (LSPR). Metal nanoparticles, especially gold and silver nanoparticles, display strong optical responses because they can support surface plasmon oscillations. In SERS, nanostructures primarily enhance Raman signals through two mechanisms: electromagnetic enhancement and chemical enhancement. When a laser irradiates a metal nanoparticle, it excites collective oscillations of free electrons on the surface, forming surface plasmon waves. These waves focus near the metal surface, generating a strong local electric field. If molecules approach the nanoparticle surface, the Raman scattering signal is significantly amplified by this enhanced electric field. Besides electromagnetic effects, the interaction between molecules and the metal surface also affects the Raman signal. This effect is usually related to chemical bonding and electron transfer processes between molecules and nanostructures, and can sometimes further enhance the Raman signal. Therefore, metal nanoparticles, especially silver (Ag) and gold (Au), are commonly used as enhancing substrates in SERS detection.

[0007] The enhancement of the SERS signal mainly stems from optical gain (based on surface plasmon resonance) and localized enhancement of the electromagnetic field, and these enhancement effects are closely related to the design of micro / nanostructures. The design of micro / nanostructures can optimize surface plasmon resonance, further enhancing the interaction between light and matter, thereby increasing the SERS signal intensity. Common micro / nanostructures include nanoparticles, nanopore arrays, nanowires and nanostructure arrays, metal thin films, and coatings. The micro / nanostructure chosen in this study is based on a nanopore array. Nanopore structures can increase the interaction region between molecules and the surface at the nanoscale, causing an enhancement of the local electromagnetic field, thus further improving the SERS signal. This structure not only possesses the excellent plasmon properties of silver itself but also generates unique optical phenomena through periodic arrangement. The porous structure creates dense electromagnetic field "hot spots." The periodic array introduces lattice resonance, further amplifying and homogenizing the enhancement effect.

[0008] After the nanopore array structure is fabricated, nanoparticle structures are introduced into each pore of the array to form a nanopore-particle co-embedded array. This novel structure, by constructing a three-dimensional, multi-level composite structure, can produce enhancement effects far exceeding those of simple pore arrays or nanoparticles. Compared to a simple silver nanopore array structure, the pore-particle co-embedded structure can generate extremely strong electromagnetic field localization by forming three-dimensional hot spots, especially controllable nano-gap structures. This significantly increases the number and distribution density of hot spots, resulting in a synergistic enhancement effect. Although the random distribution of nanoparticles may introduce signal fluctuations, this can be optimized through precise sputtering control. By accurately controlling the sputtering time, the position of the plasma resonance peak can be finely adjusted to better match the excitation light and the Raman characteristics of the target molecules, thereby maximizing the enhancement effect.

[0009] Introducing Ag nanoparticles into ordered silver nanopores essentially combines the advantages of periodic light modulation with the extreme field enhancement advantages of random nano-interstic gaps by constructing a synergistic system of "ordered large structures + disordered small particles." This is a powerful strategy for achieving ultra-high sensitivity and high hotspot density SERS substrates. Although it places higher demands on the fabrication process, the potential for performance improvement is enormous.

[0010] This invention employs a bottom-up approach to fabricate a silver nanopore-particle co-embedded array. This method is low-cost, easily scalable, and the finished product is simple and easy to synthesize. The multi-level composite system, with disordered small particles embedded within an ordered macrostructure framework, synergistically produces superior SERS performance. The pore structure provides a regular, periodic light modulation platform, while the nanoparticles within the pores form numerous uniformly distributed sub-nanometer gaps with the pore walls and between the particles. These three-dimensional "hot spots" significantly enhance both the electromagnetic field enhancement effect and the hot spot density, thereby pushing detection sensitivity to new heights. Simultaneously, this structure inherits the excellent signal reproducibility of ordered substrates and increases chemisorption sites through nanoparticles, demonstrating great potential for ultrasensitive trace detection (such as biomarkers and environmental pollutants), making it one of the ideal designs for practical high-performance SERS substrates. By adjusting the pore size, pore spacing, and the size of the nanoparticles within the pores, the resonance peak during SERS detection can be precisely tuned to the required excitation laser wavelength and Raman scattering wavelength range, achieving maximum signal enhancement.

[0011] To achieve the above objectives, this application provides the following technical solution: A method for preparing a silver nanopore-particle co-embedded array includes the following steps: A self-assembled polymer microsphere array was constructed on a silicon substrate; the size of the microspheres was reduced using reactive ion etching. The microsphere array, after being shrunk, is placed on the sample stage; the sample stage is placed above the target material, and a silver film is sputtered onto the microsphere array by magnetron sputtering; thus, a polymer microsphere array covered with a silver film is obtained. A silver nanopore array was obtained by removing the microsphere array from the substrate. The Si substrate exposed at the bottom of the micropores by removing the microsphere array is etched by reactive ion etching to form regularly arranged recesses on the upper surface of the substrate; the diameter of the recesses is between 250 and 350 nm, and the depth of the recesses is not less than their diameter. Silver is then magnetron sputtered again on the substrate surface. Utilizing the shadowing effect of the edge of the recess, Ag particles are deposited in the central region at the bottom of the recess, forming a silver nanopore-particle co-embedded array; the Ag particles have a particle size of 45nm~135nm.

[0012] Preferably, the reduction of microsphere size using reactive ion etching specifically includes: The etching gas used was O2, the etching power was 125W, the pressure was 20 Pa, the gas flow rate was 50 sccm, and the etching time was 40s.

[0013] Preferably, the further magnetron sputtering of silver on the substrate surface specifically includes: a sputtering pressure of 0.6 Pa, an Ag sputtering power of 0.01 kW, and a sputtering time of 35 s to 85 s. By adjusting the sputtering time, different Ag nanostructures are formed inside the recessed holes. Figure 5 In (b), it can be observed that when the sputtering time is 35 s, the particle size of most nanoparticles remains between 45 nm and 135 nm, the nanoparticles are very compactly arranged, and the gap between particles remains within 10 nm. When the sputtering time reaches 85 s, the particle size can be observed from... Figure 5 In (c), it was observed that the Ag in the pores had aggregated into a bulk nanostructure.

[0014] Preferably, silver film is sputtered on the microsphere array by magnetron sputtering, specifically including: Ag sputtering using magnetron sputtering, sputtering pressure of 0.6 Pa, Ag sputtering power of 0.01 KW, and total sputtering time of 2 min 30 s.

[0015] Preferably, in step S4, the coating process specifically includes the following steps: during the coating process, Ag single sputtering is selected, ensuring that the pressure inside the chamber is 0.6 Pa during sputtering, adjusting the Ag sputtering power to 0.01 KW, and the sputtering time to 150s.

[0016] Preferably, the etching of the Si substrate at the bottom of the micropores exposed by removing the microsphere array through reactive ion etching specifically includes: using SF6 as the etching gas, with a flow rate of 65 sccm, a working pressure of 20 Pa, a power of 125 W, and an etching time of 40 s.

[0017] The present invention also provides a silver nanopore-particle co-embedded array structure prepared by the above preparation method.

[0018] This invention also provides an application of the aforementioned silver nanopore-particle co-embedded array structure for the detection of low concentrations of 4-MBA, comprising the following steps: Silver nanopore-particle co-intercalation array structure at concentrations as low as 10 -3 mol L -1 After soaking in 4-MBA ethanol solution for 30 min, the silver nanopore-particle co-embedded array structure was cleaned to remove unabsorbed 4-MBA molecules, and then soft-dried under N2 gas. Select a laser wavelength of 532 nm or 633 nm for SERS detection; The Raman signal of 4MBA molecules was amplified by 10 using the aforementioned silver nanopore-particle co-embedded array structure. 6 ~10 14 Double the value to identify the characteristic peaks of 4MBA molecules; The characteristic peaks of the 4MBA molecule include: 1078 cm⁻¹ -1 CS stretching vibration, 1185 cm -1 CH in-plane bending vibration, 1585cm -1 C=C stretching vibration.

[0019] This invention also provides an application of the aforementioned silver nanopore-particle co-embedded array structure for pesticide residue detection of tetramethylthiuram disulfide, comprising the following steps: Obtain an acetone solution of tetramethylthiuram disulfide. The concentration of tetramethylthiuram disulfide in the solution was 10. -8 mol L -1 ~10 -3 mol L -1 ; The silver nanopore-particle co-embedded array structure is immersed in the solution, so that the sulfur atoms in the pesticide molecules form Ag-S chemical bonds with the silver surface. The silver nanopore-particle co-embedded array structure is then cleaned to remove unadsorbed molecules and then dried. SERS detection was performed using laser wavelengths of 532 nm or 633 nm. Residue detection was performed by identifying the characteristic peak of tetramethylthiuram disulfide, including the peak at 1379 cm⁻¹. -1 CN stretching vibration, 1142 cm -1 C=S stretching vibration, 1500-1550 cm -1 NCS skeletal vibration or CH3 deformation vibration.

[0020] The technical solution provided in this application can achieve the following beneficial effects: This application addresses the shortcomings of existing technologies by proposing a method for preparing a silver nanopore-particle co-embedded array structure, which combines two regular arrays of nanopores and particles. This structure inherits the good signal reproducibility of ordered substrates and adds chemical adsorption sites through nanoparticles, demonstrating great potential for achieving ultrasensitive trace detection (such as biomarkers and environmental pollutants).

[0021] The nanoporous structure also allows each unit to be isolated and not affect each other. Each pore unit is only about 0.5 µm in size, which can avoid the problems of clogging and mutual interference between units. The silver nanopores are independent of each other, avoiding the problem of mutual interference between units.

[0022] The present invention provides an application of a nanopore array in SERS detection. The size of the nanopores is adapted to that of 4MBA and thiram. Based on the good signal reproducibility of the present invention, it can be used to detect trace amounts of 4MBA and pesticide residues. Attached Figure Description

[0023] Figure 1 is a schematic diagram of the preparation process of the present invention.

[0024] Figure 2 shows the SEM image of the microsphere array assembled on the Si substrate.

[0025] Figure 3 shows the SEM image of the microsphere array after 40 s of reactive ion etching treatment.

[0026] Figure 4 shows the SEM image of the nanopore array left after the microsphere array is removed, after sputtering an Ag film of about 60 nm onto the microsphere array using magnetron sputtering.

[0027] Figure 5 shows the SEM images of the finished nanopore arrays observed at a tilted 45° angle after the silicon substrate was treated with reactive ion etching for 40 s and then sputtered again for different times. Among them, (a) is the SEM image of the finished product after sputtering for 0 s, (b) is the SEM image of the finished product after sputtering for 35 s, and (c) is the SEM image of the finished product after sputtering for 85 s.

[0028] Figure 6 shows the SERS test results of the finished product. The data in the upper right corner is the sputtering time of Ag during the second sputtering.

[0029] Figure 7 shows the data graph of the finished product used for pesticide residue detection. All test reagents were at a concentration of 10. -4 mol L -1 The data in the upper right corner of the tetramethylthiuram disulfide solution represents the sputtering time of Ag during the second sputtering. 5000 in the figure represents the Raman intensity scale on the vertical axis. It can be observed that the detection effect is best when the sputtering time is moderate and the Ag within the pores exhibits a nanoparticle structure. Without a second sputtering, the SERS enhancement effect of the pore array without Ag particle modification mainly relies on the two-dimensional planar "hot spots" at the nanopore edges. However, with the second sputtering, the pore array modified with Ag nanoparticles forms three-dimensional hot spots between "pore walls and particles" and between "particles," especially the controllable nano-gap (e.g., <10 nm) which can generate extremely strong electromagnetic field localization. As the sputtering time further increases, the Ag structure within the pores accumulates into a blocky structure. At this point, the Ag structure surface tends to be flat, lacking the nano-gap that can generate ultra-high enhancement; its enhancement effect mainly relies on the rough surface, far less than the former.

[0030] Figure 8 shows the data of the finished product used for pesticide residue detection. a, b, c, d, e, and f correspond to a concentration of 10. -8 10 -7 10 -6 10 -5 10 -4 10 -3 mol L -1 Tetramethylthiuram disulfide solution. Detailed Implementation

[0031] To further understand this application, the preparation method of the silver nanopore-particle co-embedded array provided in this application will be described in detail below with reference to the embodiments. The scope of protection of this application is not limited to the following embodiments.

[0032] The silver nanopore-particle co-embedded array provided by this invention belongs to the category of defined region nanopore arrays, comprising: a silicon wafer substrate with a micropore array on its surface, and a metal nanostructure distributed in each micropore; the size of the metal nanostructure is 0.3~0.5 μm; in the micropore array, each micropore has the same shape and size, so that each reaction is carried out under the same conditions without affecting each other.

[0033] This invention also provides the application of the aforementioned silver nanopore-particle co-embedded array in SERS detection. Using 4-methylbenzoic acid (4MBA) as a probe molecule, it is dissolved in ethanol to prepare a 1 mM solution. The substrate is immersed in the 4MBA solution and incubated for a period of time (e.g., 1 hour). After the 4MBA molecules are adsorbed onto the metal surface via thiol groups, the substrate is removed, washed with solvent to remove unadsorbed 4MBA molecules, and then dried. Before SERS detection, a suitable laser wavelength (e.g., 532 nm or 633 nm) is selected to avoid photodegradation of the sample. After adjusting the laser power and integration time, the prepared sample is placed on the sample stage of a Raman spectrometer. The laser beam is focused on the sample surface, and the SERS spectrum is acquired. Finally, the acquired SERS spectrum is analyzed using software to identify the characteristic peaks of 4MBA. Common 4MBA characteristic peaks include: 1078 cm⁻¹. -1 (CS stretching vibration), 1185 cm -1 (In-plane bending vibration of CH), 1585 cm -1 (C=C stretching vibration), etc.

[0034] This invention also provides an application of silver nanopore-particle co-embedded array in the detection of pesticide residues. Tetramethylthiuram disulfide (Thiram) is used as the detection substance. It is dissolved in acetone to prepare detection solutions of different concentrations. The substrate is immersed in the solution and incubated for a period of time (e.g., 1 hour) until the sulfur atoms in the molecules form Ag-S chemical bonds with the silver surface, achieving tight chemical adsorption. The substrate is then removed, washed with a solvent to remove unadsorbed molecules, and then dried. Before SERS detection, a suitable laser wavelength (e.g., 532 nm or 633 nm) is selected to avoid photodegradation of the sample. After adjusting the laser power and integration time, the prepared sample is placed on the sample stage of a Raman spectrometer. The laser beam is focused on the sample surface, and the SERS spectrum is acquired. Finally, the acquired SERS spectrum is analyzed using software to identify the characteristic peaks of tetramethylthiuram disulfide. Common characteristic peaks include: 1379 cm⁻¹. -1 (CN stretching vibration), 1142 cm -1 (C=S stretching vibration), 1500-1550 cm -1 (NCS skeleton vibration or CH3 deformation vibration), etc.

[0035] In some examples, the diameter of the metal nanopore structure is about 0.3 μm and the depth is about 0.6 μm, wherein the metal layer at the pore opening of the metal nanopore is about 0.2 μm deep and the pit in the Si layer below the metal nanopore is about 0.4 μm deep.

[0036] This invention also provides a method for preparing the above-mentioned silver nanopore-particle co-embedded array, such as... Figure 1 As shown, it includes the following steps: S1 obtains a silicon wafer as a substrate; S2 involves slowly adding the well-dispersed microsphere solution dropwise into a container filled with deionized water, thus fabricating a polystyrene microsphere array on a silicon wafer through gas-liquid interface self-assembly. Figure 2 As shown, a substrate assembled with a microsphere array was obtained; S3 involves etching the assembled microspheres onto the array substrate, specifically including the following steps: the etching gas is O2, the gas flow rate is 50 sccm, the working pressure is 20 Pa, the power is 125 W, and the etching time is 40 s, so that the organic microspheres are etched into smaller sizes, such as... Figure 3 As shown.

[0037] S4 involves coating the substrate with assembled microspheres, specifically including the following steps: Ag sputtering is performed using magnetron sputtering at a sputtering pressure of 0.6 Pa, an Ag sputtering power of 0.01 kW, and a total sputtering time of 2 min 30 s. After sputtering, a metal film is obtained on the substrate. Then, adhesive tape is adhered to the substrate surface to remove the organic microspheres, thus forming the nanopore array. Figure 4As shown.

[0038] S5 performs reactive ion etching on the substrate with the Ag nanopore array attached. The gas used is SF6 with a flow rate of 65 sccm, a working pressure of 20 Pa, a power of 125 W, and an etching time of 40 s. This process etches the Si substrate, which is exposed to air at the bottom of the micropores after the microsphere array is removed, forming a recessed pore-like structure.

[0039] S6 performs a second coating process on the substrate after reactive ion etching, specifically including the following steps: Ag sputtering is performed using magnetron sputtering at a sputtering pressure of 0.6 Pa and an Ag sputtering power of 0.01 KW. Sputtering times are 35s, 60s, and 85s. The effects of no sputtering, sputtering for 35s, and sputtering for 85s are as follows: Figure 5 As shown, the recessed circular hole structure can be regarded as a high aspect ratio structure. When Ag particles generated by magnetron sputtering fly towards the recessed structure, the edge of the circular hole will act like an eave, creating a "shielding" or "shadowing" effect on the incident particles. By adjusting different sputtering times, different Ag nanoparticle structures can be formed in the central region at the bottom of the circular hole.

[0040] The SERS detection pattern of the product prepared by the above steps is shown in Figure 6.

[0041] Adjusting the sputtering time of Ag in step S6 affects the morphology of the product, thus influencing its effectiveness in pesticide residue detection. The experiment used tetramethylthiuram disulfide solution of the same concentration, and the detection results are shown in Figure 7. The figure shows that the intensity is highest when the Ag sputtering time is 50 seconds, and lowest when no Ag sputtering is performed (Ag sputtering time is 0 seconds). The effects of adjusting the concentration of tetramethylthiuram disulfide solution in pesticide residue detection experiments are shown in Figure 7. Figure 8 As shown.

[0042] In one embodiment, when performing gas-liquid interface self-assembly, the selected polystyrene microspheres have a diameter of 500 nm. The etching time is 40 s, thereby avoiding the situation where the nanopore array cannot be formed due to an etching time that is too short, and also avoiding the situation where the polystyrene microspheres disappear or the diameter of the microspheres is smaller than the film thickness due to an etching time that would prevent the microspheres from being removed by adhesive tape after coating.

[0043] Example 1 Polystyrene microsphere arrays were prepared on silicon wafer substrates via a self-assembly method at the gas-liquid interface.

[0044] 850 μL of a 0.27% w / v polystyrene microsphere solution was loaded into a syringe. A clean silicon wafer with a diameter of 15 cm was placed at the bottom of a culture dish. A second silicon wafer was then placed in the dish at a 45° angle. Ultrapure water was then slowly added to the dish until the water level was centered on the second silicon wafer. The syringe containing the polystyrene microsphere solution was held close to the edge of the culture dish. The injection rate was adjusted to ensure that each drop of solution was evenly dispersed on the water surface through the second silicon wafer. The syringe was stopped when a PS monolayer film formed on the culture dish. To remove PS particles below the water level, a peristaltic pump was used at a rate of 80 mL / min. -1 Change the water at a rate of 2 h, then use a peristaltic pump at a rate of 40 mL / min. -1 Water was pumped at a rate until the monolayer PS film fell onto the silicon wafer. Finally, the two-dimensional (2D) PS template on the silicon wafer was dried and stored at room temperature.

[0045] The size of PS spheres was reduced by reactive ion etching (RIE-10NR) with a working power of 125 W, an O2 gas flow rate of 50 sccm, a working pressure of 20 Pa, and an etching time of 40 s.

[0046] The processed micropore array was placed on the target material and coated by magnetron sputtering. During the coating process, Ag single sputtering was selected to ensure that the pressure inside the chamber was 0.6 Pa, the Ag sputtering power was adjusted to 0.01 KW, and the sputtering time was 150s.

[0047] The Si substrate between the Ag thin films was etched using reactive ion etching (RIE-10NR) to form a recessed pore structure on the substrate. The operating power was 125 W, the SF6 gas flow rate was 65 sccm, the operating pressure was 20 Pa, and the etching time was 40 s.

[0048] The processed micropore array was placed on the target material and coated by magnetron sputtering. During the coating process, Ag single sputtering was selected to ensure that the pressure inside the chamber was 0.6 Pa, the Ag sputtering power was adjusted to 0.01 KW, and the sputtering time was 35s.

[0049] Example 2 includes Example 2-1 and Example 2-2.

[0050] Example 2-1 The difference from Example 1 is that the second coating sputtering time is 60s, while the other preparation methods and conditions are the same as in Example 1.

[0051] Example 2-2 The difference from Example 1 is that the second coating sputtering time is 85s, while the other preparation methods and conditions are the same as in Example 1.

[0052] Example 3 The difference from Example 1 is that the reactive ion etching time for processing the microsphere array is 55s, while the other preparation methods and conditions are the same as in Example 1.

[0053] Example 4 includes Example 4-1 and Example 4-2.

[0054] Example 4-1 The difference from Example 1 is that the second coating sputtering time is 60s, while the other preparation methods and conditions are the same as in Example 1.

[0055] Example 4-2 The difference from Example 3 is that the second coating sputtering time is 85s, while the other preparation methods and conditions are the same as in Example 3.

[0056] Example 5 The difference from Example 1 is that the reactive ion etching time for processing the microsphere array is 70s, while the other preparation methods and conditions are the same as in Example 1.

[0057] Example 6 includes Example 6-1 and Example 6-2.

[0058] Example 6-1 The difference from Example 1 is that the second coating sputtering time is 60s, while the other preparation methods and conditions are the same as in Example 1.

[0059] Example 6-2 The difference from Example 1 is that the second coating sputtering time is 85s, while the other preparation methods and conditions are the same as in Example 1.

[0060] Example 7 The difference from Example 1 is that the second coating sputtering time is 0s, while the other preparation methods and conditions are the same as in Example 1.

[0061] Example 8 Application of silver nanopore-particle co-embedded array in SERS detection Silver nanopore-particle co-intercalation array substrates in 10 -3 mol L -1 The sample was immersed in 4-MBA ethanol solution for 30 min and thoroughly washed three times to remove unabsorbed 4-MBA molecules. Finally, the sample was soft-dried under N2 gas. The SERS intensity of the sample was measured together with the substrate sputtered at different times during the second sputtering, and the changes in the second sputtering time were observed.

[0062] Silver nanopore-particle co-intercalation array substrates in 10 -8 mol L-1 ~10 -3 mol L -1 The samples were immersed in tetramethylthiuram acetone solutions of different concentrations for 30 min, and thoroughly washed three times to remove unabsorbed tetramethylthiuram acetone molecules. Finally, the samples were soft-dried under N2 gas.

[0063] Using a scanning electron microscope (SEM), we can observe the morphology of a silver nanopore-particle co-embedded array. A Renishaw Raman System 2000 confocal microscopy spectrometer was used, equipped with a charge-coupled device (CCD) detector and a holographic notch filter, to acquire Raman spectra. The SERS radiation wavelength of the air-cooled argon-ion laser (20 mW) was 532 nm. The laser beam was focused onto a 1-micrometer diameter spot using a 50x telephoto objective lens, a Leica DMLM system with a 180° backscattering geometry, and a signal acquisition time set to 10 seconds.

[0064] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for preparing a silver nanopore-particle co-embedded array, characterized in that, Includes the following steps: A self-assembled polymer microsphere array was constructed on a silicon substrate; the size of the microspheres was reduced using reactive ion etching. The microsphere array, after being shrunk, is placed on the sample stage; the sample stage is placed above the target material, and a silver film is sputtered onto the microsphere array by magnetron sputtering; thus, a polymer microsphere array covered with a silver film is obtained. A silver nanopore array was obtained by removing the microsphere array from the substrate. The Si substrate exposed at the bottom of the micropores by removing the microsphere array is etched by reactive ion etching to form regularly arranged recesses on the upper surface of the substrate; the diameter of the recesses is between 250 and 350 nm, and the depth of the recesses is not less than their diameter. Silver is then magnetron sputtered again on the substrate surface. Utilizing the shadowing effect of the edge of the recess, Ag particles are deposited in the central region at the bottom of the recess, forming a silver nanopore-particle co-embedded array; the Ag particles have a particle size of 45nm~135nm.

2. The method for preparing the silver nanopore-particle co-embedded array as described in claim 1, characterized in that, The method of reducing the size of microspheres using reactive ion etching specifically includes: The etching gas used was O2, the etching power was 125W, the pressure was 20 Pa, the gas flow rate was 50 sccm, and the etching time was 40s.

3. The method for preparing the silver nanopore-particle co-embedded array structure as described in claim 1, characterized in that, The process of magnetron sputtering silver again on the substrate surface specifically includes: sputtering pressure of 0.6 Pa, Ag sputtering power of 0.01 KW, and sputtering time of 35s to 60s. By adjusting the sputtering time, different Ag nanostructures are formed inside the concave holes.

4. The method for preparing the silver nanopore-particle co-embedded array structure as described in claim 1, characterized in that, Silver films were sputtered onto a microsphere array by magnetron sputtering, specifically including: Ag sputtering using magnetron sputtering, with a sputtering pressure of 0.6 Pa, an Ag sputtering power of 0.01 KW, and a total sputtering time of 2 min 30 s.

5. The method for preparing the silver nanopore-particle co-embedded array structure as described in claim 1, characterized in that, In step S4, the coating process specifically includes the following steps: during the coating process, Ag single sputtering is selected, ensuring that the pressure inside the chamber is 0.6 Pa during sputtering, adjusting the Ag sputtering power to 0.01 KW, and the sputtering time to 150s.

6. The method for preparing the silver nanopore-particle co-embedded array structure as described in claim 1, characterized in that, The etching of the Si substrate at the bottom of the micropores exposed by removing the microsphere array via reactive ion etching specifically includes: using SF6 as the etching gas, with a flow rate of 65 sccm, an operating pressure of 20 Pa, a power of 125 W, and an etching time of 40 s.

7. The silver nanopore-particle co-embedded array structure prepared by the preparation method according to any one of claims 1 to 6.

8. The application of the silver nanopore-particle co-embedded array structure as described in claim 7, characterized in that, The method for detecting low concentrations of 4-MBA includes the following steps: Silver nanopore-particle co-intercalation array structure at concentrations as low as 10 -3 mol L -1 After soaking in 4-MBA ethanol solution for 30 min, the silver nanopore-particle co-embedded array structure was cleaned to remove unabsorbed 4-MBA molecules, and then soft-dried under N2 gas. Select a laser wavelength of 532 nm or 633 nm for SERS detection; The Raman signal of 4MBA molecules was amplified by 10 using the aforementioned silver nanopore-particle co-embedded array structure. 6 ~10 14 Double the value to identify the characteristic peaks of 4MBA molecules; The characteristic peaks of the 4MBA molecule include: 1078 cm⁻¹ -1 CS stretching vibration, 1185 cm -1 CH in-plane bending vibration, 1585 cm -1 C=C stretching vibration.

9. The application of the silver nanopore-particle co-embedded array structure as described in claim 7, characterized in that, The pesticide residue detection method for tetramethylthiuram disulfide includes the following steps: Obtain an acetone solution of tetramethylthiuram disulfide; The concentration of tetramethylthiuram disulfide in the solution was 10. -8 mol L -1 ~10 -3 mol L -1 ; The silver nanopore-particle co-embedded array structure is immersed in the solution, so that the sulfur atoms in the pesticide molecules form Ag-S chemical bonds with the silver surface. The silver nanopore-particle co-embedded array structure is then cleaned to remove unadsorbed molecules and then dried. SERS detection was performed using laser wavelengths of 532 nm or 633 nm. Residue detection was performed by identifying the characteristic peak of tetramethylthiuram disulfide, including the peak at 1379 cm⁻¹. -1 CN stretching vibration, 1142 cm -1 C=S stretching vibration, 1500-1550 cm -1 NCS skeletal vibration or CH3 deformation vibration.

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