A preparation method of SERS substrate for multi-component residue detection

Abstract

The present invention belongs to the technical field of SERS substrate preparation, and specifically relates to a method for preparing an SERS substrate for multi-component residue detection. The steps include: selecting a patterned sapphire substrate with a micro-nano structured surface; designing various arrangement methods and establishing a physical model of a laminate with a longitudinal layer-by-layer deposition distribution of a multi-component SERS effect material; obtaining a laminate substrate with a multi-layer deposition structure according to physical vapor deposition and chemical vapor deposition methods; using a mechanical cutting method to obtain a flat surface with a transverse distribution of multi-component materials; using a mechanical scribing method to scribe an ordered array structure to complete the processing steps of the SERS substrate with a transverse and longitudinal distribution of multi-component materials; soaking the processed SERS substrate in a solution and drying it, and evaluating the SERS activity through Raman spectroscopy to complete the preparation. By constructing a transverse and longitudinal distribution of multi-component materials on the surface of the SERS substrate, the present invention can increase the detection sensitivity of multi-component residues.

Description

Technical Field

[0001] The present invention belongs to the technical field of SERS substrate preparation, and particularly relates to a method for preparing an SERS substrate for multi-component residue detection. Background Art

[0002] As an emerging spectral detection technology, surface-enhanced Raman scattering (SERS) technology uses the "fingerprint characteristics" of molecules to identify target substances, and has significant advantages in terms of detection cycle, technical difficulty, and detection cost. Therefore, SERS technology has become one of the methods with great application potential and research value in trace detection fields such as environmental detection, food safety, and biomedicine. However, with the requirements of detection technology and inspection scope for SERS technology, especially for multi-component detection substances in complex mixtures, such as the detection of harmful substances in foods such as milk and tea, the detection sensitivity of the current SERS substrate is unstable. Therefore, there is an urgent need to develop an SERS substrate suitable for a variety of detection substances.

[0003] Since different substances to be detected have different detection sensitivities to different SERS effect materials, if it is possible to explore and construct a multi-component SERS effect material to be distributed in a certain way on the same SERS substrate, and realize the combination and redistribution of the SERS effect material on the substrate, the ability of SERS to detect multi-component substances will be raised to a new level.

[0004] Currently, common SERS substrate materials are generally of a single type or in the form of a fixed two types of materials. Therefore, when detecting multi-component substances to be detected, the detection ability is very limited. In order to prepare an SERS substrate with higher sensitivity, it is possible to break through the conventional thinking, combine and deposit multi-component SERS effect materials according to a certain rule, and combine methods such as mechanical processing to obtain an SERS substrate with a multi-component material distribution in the horizontal and vertical directions, so that it can be competent for the highly sensitive detection of multi-component residues. Summary of the Invention

[0005] According to the deficiencies in the above prior art, the purpose of the present invention is to provide a method for preparing an SERS substrate for multi-component residue detection, which can increase the detection sensitivity of multi-component residues by constructing a horizontal and vertical distribution of multi-component materials on the SERS substrate surface.

[0006] To achieve the above object, the present invention provides a method for preparing an SERS substrate for multi-component residue detection, including the following steps:

[0007] S1. Select a patterned sapphire substrate with a micro-nano structure surface as the base mold for longitudinally depositing multi-component SERS effect materials;

[0008] S2. Design various permutations by combining three factors: material type, deposition thickness, and deposition sequence, and establish a physical model of a laminate for the longitudinal layer-by-layer deposition distribution of the multi-component SERS effect material, where the material types are gold, silver, transition metal oxides, and two-dimensional materials;

[0009] S3. According to the physical vapor deposition and chemical vapor deposition methods, and based on the physical model of the laminate, select any one permutation and perform layer-by-layer deposition of the multi-component SERS effect material on a patterned sapphire substrate with a micro-nano structured surface to obtain a laminate substrate with a multi-layer deposition structure;

[0010] S4. Use the mechanical cutting method, set the cutting thickness, and horizontally cut the surface material of the laminate substrate to obtain a flat surface with a lateral distribution of multi-component materials;

[0011] S5. Use the mechanical scribing method to scribe an ordered array structure on the surface with a lateral distribution of multi-component materials, and form grooves or structures with a longitudinal distribution of multi-component materials in the scribing depth direction to complete the processing step of the SERS substrate with a transverse and longitudinal distribution of multi-component materials;

[0012] S6. Immerse the processed SERS substrate in a test molecular solution containing two or more components, then naturally dry it in a dust-free environment, and evaluate the SERS activity by Raman spectroscopy after drying to complete the preparation of the SERS substrate.

[0013] As a preferred embodiment of the present invention, in S1, the patterned sapphire substrate has a functionalized curved surface formed by an ordered array of micro-nano structures, and the micro-nano structures are spherical, pyramid-shaped, or conical.

[0014] As a preferred embodiment of the present invention, in S2, the transition metal oxides include titanium dioxide, copper oxide, and zinc oxide, and the two-dimensional materials include graphene and molybdenum disulfide.

[0015] As a preferred embodiment of the present invention, in S2, the arrangement method is specifically as follows: for each material, set its deposition thickness and the deposition sequence of each material, where each material can be deposited in multiple layers.

[0016] As a preferred embodiment of the present invention, in S3, gold, silver, and transition metal oxides are deposited by physical vapor deposition, that is, using a vacuum multi-target magnetron sputtering coating machine for deposition, and two-dimensional materials are deposited by chemical vapor deposition method, and finally form a multi-layer material stack with a curved structure in the longitudinal section, that is, a SERS substrate with a surface layer having a multi-layer deposition structure.

[0017] As a preferred embodiment of the present invention, in S4, use ultra-precision turning to horizontally cut the surface material of the multi-layer deposition structure.

[0018] As a preferred embodiment of the present invention, in step S5, two sets of mutually perpendicular parallel lines are scribed on the surface with a lateral distribution of multi-component materials by atomic force scribing to form a surface micro-texture structure.

[0019] As a preferred embodiment of the present invention, in step S6, a binary mixed solution of rhodamine 6G with a concentration of 10 -7 M and malachite green with a concentration of 10 -6 M is prepared. The SERS substrate with lateral and longitudinal distributions of multi-component materials is immersed in the binary mixed solution for 20 minutes. When evaluating the SERS activity by Raman spectroscopy, a 633 nm laser is used for excitation with a power of 5 mW and an exposure time of 20 s, and the characteristic peak values of the Raman signals of R6G molecules and MG molecules are observed.

[0020] The beneficial effects of the present invention are as follows:

[0021] The present invention fully considers the sensitivities of different SERS-effect materials to different detection molecules, and at the same time considers the mutual interference of multi-component substances to be detected. Based on deposition technology and machining technology, the preparation of a multi-component material SERS substrate is realized, providing technical support for the sensitive detection of multi-component substances to be detected.

[0022] The present invention proposes a method for preparing an SERS substrate for multi-component residue detection, and elaborates in detail the preparation process of an SERS substrate with lateral and longitudinal distributions of multi-component materials by layer-by-layer deposition on the deposited surface of a substrate with a functional curved surface, and by using mechanical cutting methods and scribing methods, which can improve the adaptability and sensitivity of the SERS substrate, and thus realize the effective detection of multi-component substances to be detected. Description of the Drawings

[0023] Figure 1 is the process schematic diagram of the present invention;

[0024] Figure 2 is the PSS structure diagram used in the embodiment of the present invention, Figure 2 where (a) in Figure 2 is the surface structure of a 2-inch PSS;

[0025] Figure 3 is the schematic cross-sectional view of the laminated substrate with a multi-layer deposition structure after cutting in the embodiment of the present invention, Figure 3 where (a) in Figure 3 is the schematic cross-sectional view of the surface of a 2-inch structured PSS after cutting;

[0026] Figure 4 is the schematic diagram of the atomic force scribing path in the embodiment of the present invention;

[0027] Figure 5 It is the surface-enhanced Raman test curve graph of the binary solution in the embodiment of the present invention. Specific embodiments

[0028] The embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0029] As Figure 1 shown, a method for preparing a SERS substrate for multi-component residue detection includes the following steps:

[0030] S1. Select a patterned sapphire substrate with a micro-nano structured surface as the substrate mold for longitudinally depositing multi-component SERS effect materials;

[0031] S2. Design a variety of arrangement modes combined with three factors of material type, deposition thickness, and deposition order, and establish a physical model of a laminate for the longitudinal layer-by-layer deposition distribution of multi-component SERS effect materials, where the material types are gold, silver, transition metal oxides, and two-dimensional materials (i.e., multi-component SERS effect materials);

[0032] S3. According to the physical vapor deposition (PVD) and chemical vapor deposition (CVD) methods, and based on the physical model of the laminate, select any one of the arrangement modes based on material type, deposition thickness, and deposition order, and implement the layer-by-layer deposition of multi-component SERS effect materials on the patterned sapphire substrate with a micro-nano structured surface to obtain a laminate substrate with a multi-layer deposition structure;

[0033] S4. Use a mechanical cutting method, set the cutting thickness, and horizontally cut the surface material of the laminate substrate to obtain a flat surface with a horizontal distribution of multi-component materials;

[0034] S5. Use a mechanical scribing method to scribe an ordered array structure on the surface with a horizontal distribution of multi-component materials, and form grooves or structures with a longitudinal distribution of multi-component materials in the scribing depth direction to complete the processing step of the SERS substrate with a horizontal and longitudinal distribution of multi-component materials;

[0035] S6. Immerse the processed SERS substrate in a test molecular solution containing two or more components, then naturally dry it in a dust-free environment, and evaluate the SERS activity by Raman spectroscopy after drying to complete the preparation of the SERS substrate.

[0036] A patterned sapphire substrate (Patterned Sapphire Substrate, PSS) is a substrate with a specific pattern formed on a sapphire substrate through photolithography and etching techniques.

[0037] In this embodiment, patterned sapphire substrates with sizes of 2 inches and 4 inches are used as molds respectively. The 2-inch and 4-inch patterned sapphire substrates have different surface micro-nano structures, such as Figure 2 as shown.

[0038] As can be seen from Figure 2 , the micro-nano structures on the surfaces of the 2-inch and 4-inch patterned sapphire substrates are arranged in an ordered array form, and the overall surface has a complex functionalized curved surface.

[0039] A surface-structured substrate can also be prepared by precision machining as a base mold to replace the patterned sapphire substrate. The precision machining methods include plasma high-temperature machining, micro-EDM, electron beam, ion beam, etc.

[0040] In S1, the patterned sapphire substrate has a functionalized curved surface formed by an ordered array of micro-nano structures, and the micro-nano structures are spherical, pyramid-shaped or conical.

[0041] In S2, the transition metal oxides include titanium dioxide, copper oxide, and zinc oxide, and the two-dimensional materials include graphene and molybdenum disulfide.

[0042] The arrangement method is specifically as follows: for each material, its deposition thickness is set, and the deposition order of each material is set. Among them, each material can be deposited in multiple layers. A stacked material for each layer in sequence is generated in tabular form, as shown in Table 1.

[0043] Table 1 Arrangement of material types, deposition thicknesses, and deposition orders

[0044]

[0045] As can be seen from Table 1, by designing various arrangement methods combined with three factors: material type, deposition thickness, and deposition order, multiple preparation schemes for SERS substrates with horizontal and vertical distributions of multiple materials can be formed. The sequence selection in Table 1 is an example of one of the arrangement methods.

[0046] In S3, gold, silver, and transition metal oxides are deposited by physical vapor deposition, that is, deposited using a vacuum multi-target magnetron sputtering coating machine, and two-dimensional materials are deposited by chemical vapor deposition method, finally forming a multi-layer material stack with a curved structure in the longitudinal section, that is, an SERS substrate with a multi-layer deposition structure surface layer.

[0047] The vacuum multi-target magnetron sputtering coating machine is a high-performance equipment for both scientific research and production, equipped with more than 2 magnetron targets, and has the function of multi-target time-sharing / simultaneous sputtering.

[0048] In S4, the surface material of the multi-layer deposition structure is horizontally cut using ultra-precision turning. Ultra-precision turning is a machining method with extremely high machining accuracy, with a form accuracy reaching the sub-micron level and a surface roughness reaching the nano level. Its principle is to use a high-speed and high-precision turning tool to perform cutting on the workpiece.

[0049] By controlling the cutting thickness, a substrate with the same arrangement (in the case where the material type, deposition thickness, and deposition order remain completely unchanged) can be prepared, and substrates with different lateral and longitudinal distributions can be obtained according to the different positions of the cutting plane.

[0050] Taking the arrangement of ②④③⑤③①⑥ in Table 1 as an example, the vertical cross-sectional view of the laminated substrate with a multi-layer deposition structure after cutting is as Figure 3 shown, where different colors represent different material types, and the 1, 2, and 3 on the left represent the cutting surfaces corresponding to different cutting thicknesses. From Figure 3 it can be seen that for the distribution of SERS effect materials deposited on patterned sapphire substrates with different sizes and structures, it is different, and different lateral multi-material distributions of the surface material will be obtained by mechanical cutting at different cross-sections.

[0051] In S5, atomic force scribing (a type of mechanical micro-scribing) is used to scribe two groups of mutually perpendicular parallel lines with a depth of 2 microns on the surface with a lateral multi-material distribution to form a surface micro-texture. The schematic diagram of the atomic force scribing path is as Figure 4 shown. Atomic force scribing is a micro-nano processing technology based on the atomic force microscope. Its principle is to scan the material surface with a probe (tool) and apply a certain force to perform micro-nano scale scribing on the material surface. This technology can achieve precise micro-nano structure processing with high processing accuracy and can precisely control the scribing depth and shape.

[0052] From Figure 4 it can be seen that the atomic force scribing tool scribes the surface texture with a certain depth on the surface with a lateral multi-material distribution according to a certain path to form a SERS substrate with lateral and longitudinal multi-material distributions on the surface.

[0053] In S6, a binary mixed solution of rhodamine 6G (R6G) with a concentration of 10 -7 M and malachite green (MG) with a concentration of 10 -6 M is prepared, and the SERS substrate with lateral and longitudinal multi-material distributions is immersed in the binary mixed solution for 20 minutes; when evaluating the SERS activity by Raman spectroscopy, a 633 nm laser is used for excitation with a power of 5 mW and an exposure time of 20 s, and the characteristic peak values of the Raman signals of R6G molecules and MG molecules are observed.

[0054] The surface-enhanced Raman test curve of the binary mixed solution is asFigure 5 As shown, from Figure 5 it can be seen that the R6G molecule has obvious Raman shift peaks at 613 cm -1 , 1360 cm -1 and 1510 cm -1 . The MG molecule has distinct Raman shift peaks at 1174 cm -1 , 1618 cm -1 . Raman testing of the binary-component solution using the SERS substrate designed and prepared in this example shows that different components can be effectively detected.

Claims

1. A method for preparing a SERS substrate for multi-component residue detection, characterized in that It includes the following steps: S1. Select a patterned sapphire substrate with a micro-nano structured surface as the substrate mold for longitudinally depositing multi-component SERS effect materials; S2. Design various permutations by combining three factors: material type, deposition thickness, and deposition order, and establish a physical model of a laminate for the longitudinal layer-by-layer deposition distribution of multi-component SERS effect materials. The material types are gold, silver, transition metal oxides, and two-dimensional materials. The transition metal oxides include titanium dioxide, copper oxide, and zinc oxide, and the two-dimensional materials include graphene and molybdenum disulfide. Specifically, for each material, set its deposition thickness and the deposition order of each material. Among them, graphene is deposited in multiple layers; S3. According to the physical vapor deposition and chemical vapor deposition methods, and based on the physical model of the laminate, select any one of the permutations and implement layer-by-layer deposition of multi-component SERS effect materials on the patterned sapphire substrate with a micro-nano structured surface to obtain a laminate substrate with a multi-layer deposition structure; S4. Use the mechanical cutting method, set the cutting thickness, and horizontally cut the surface material of the laminate substrate to obtain a flat surface with a lateral distribution of multi-component materials; S5. Use the mechanical scribing method to scribe an ordered array structure on the surface with a lateral distribution of multi-component materials, and form grooves or structures with a longitudinal distribution of multi-component materials in the scribing depth direction, completing the processing steps of the SERS substrate with a horizontal and vertical distribution of multi-component materials and completing the preparation of the SERS substrate.

2. The preparation method of the SERS substrate for multi-component residue detection according to claim 1, characterized in that: In the above S1, the patterned sapphire substrate has a functionalized curve surface formed by an ordered array of micro-nano structures, and the micro-nano structures are spherical, pyramid-shaped, or conical.

3. The preparation method of the SERS substrate for multi-component residue detection according to claim 1, characterized in that: In the above S3, gold, silver, and transition metal oxides are deposited using physical vapor deposition, that is, deposited using a vacuum multi-target magnetron sputtering coating machine, and two-dimensional materials are deposited using chemical vapor deposition, finally forming a multi-layer material stack with a curve structure in the longitudinal section, that is, an SERS substrate with a multi-layer deposition structure surface layer.

4. The preparation method of a SERS substrate for multi-component residue detection according to claim 1, wherein: In the above S4, ultra-precision turning is used to horizontally cut the surface material of the multi-layer deposition structure.

5. The preparation method of a SERS substrate for multi-component residue detection according to claim 1, characterized in that: In the above S5, atomic force scribing is used to scribe two groups of mutually perpendicular parallel lines on the surface with a lateral distribution of multi-component materials to form a surface micro-texture.

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