Metasurface wave absorber with surface-enhanced raman scattering characteristics and preparation method thereof

Abstract

The application discloses a metasurface wave absorber with surface-enhanced Raman scattering characteristics and a preparation method thereof. The metasurface wave absorber has an Au nano-octahedron hybrid Ag nanowire structure, and the preparation method of the metasurface wave absorber is based on chemical synthesis and self-assembly in a solution environment. The working wave band of the metasurface wave absorber is located in the wavelength range of 200-800 nm, the metasurface wave absorber can effectively absorb incident light (the average light absorption rate is greater than 95%), and meanwhile, the metasurface wave absorber can realize high-sensitivity surface-enhanced Raman scattering response to 4-mercaptopyridine molecules (the detection concentration is 1x10 ‑5 mol / L, the intensity factor is 6.4-9.1x10 7 , and low-concentration detection (the detection concentration limit is 1x10 ‑ 11 mol / L).

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of functional metasurface absorber, and particularly relates to a metasurface absorber with surface enhanced Raman scattering characteristics and a preparation method thereof. BACKGROUND

[0002] In recent years, metasurface absorber has been widely concerned due to its adjustable light absorption characteristics and important application value in the field of optical sensing analysis technology-surface enhanced Raman scattering (SERS). The traditional manufacturing technology of metasurface absorber is physical lithography, nano-imprinting and the like, and this kind of technology has been reported to realize the construction design of metasurface absorber in low-frequency microwave, terahertz, high-frequency infrared, visible light and even ultraviolet light bands, and a series of exploration researches on related SERS effect have been carried out. However, due to the high cost and low production efficiency of lithography and nano-imprinting technology, the SERS functional metasurface absorber faces challenges in large-area manufacturing and practical application.

[0003] Self-assembly technology is a new emerging metasurface absorber preparation research technology, which has the advantages of low cost and large-area manufacturing in theory. By self-assembly, specific morphological noble metal nanostructures are compounded with each other to form a plasmonic resonance cavity, which can realize effective absorption and regulation of specific frequency incident light. At the same time, due to the plasmonic resonance, field enhancement and hot spot effect will also be caused, which will also make the self-assembly metasurface absorber have excellent SERS characteristics and possible applications. However, due to the limited morphologies of noble metal nano-composite structures (mostly metal nanoparticle-dielectric film-metal film “sandwich” structure) prepared by the existing reported chemical synthesis and self-assembly methods, the plasmonic resonance modes, field enhancement and hot spot effect available for design are limited. Therefore, the working waveband of the metasurface absorber prepared by the self-assembly technology is mostly concentrated in the visible-near infrared band, and the effective absorption rate of the incident light is generally low (mostly less than 90%). In addition, the SERS performance of the current self-assembly metasurface absorber is not outstanding, and related researches are rarely reported.

[0004] In summary, in the current SERS research field of self-assembly metasurface absorber, it is of great significance to explore new structure design and related manufacturing technology to obtain metasurface absorber with wide working waveband and high SERS performance, which promotes the development of practical application of metasurface absorber SERS. SUMMARY

[0005] The present application proposes a metasurface absorber with excellent surface enhanced Raman scattering characteristics and a preparation method thereof, aiming at the scientific problems such as narrow working waveband, low light absorption efficiency and non-outstanding SERS performance in the current SERS research field of self-assembly metasurface absorber.

[0006] The application adopts the following technical solutions:

[0007] The application discloses an ultrathin metamaterial absorber with surface-enhanced Raman scattering characteristics, which comprises Au nanooctahedron hybrid Ag nanowire structures.

[0008] Specifically, the ultrathin metamaterial absorber with surface-enhanced Raman scattering characteristics comprises Au nanooctahedron hybrid Ag nanowire structures. The Au nanooctahedron is attached to the surface of the Ag nanowire in a random orientation and a suitable coverage, and the formed hybrid structure presents a three-dimensional interlaced state. The ultrathin metamaterial absorber has an average light absorption rate of >95% in the ultraviolet-visible light band of 200-800 nm, and the surface-enhanced Raman scattering detection enhancement factor of the ultrathin metamaterial absorber for 4-mercaptopyridine molecules (concentration of 1×10 -5 mol / L) is 6.4-9.1×10 7 , and the detection concentration limit is 1×10 -11 mol / L.

[0009] Further, the Au nanooctahedron has a uniform morphology, and the edge length size is about 75 nm.

[0010] Further, the diameter of the Ag nanowire is about 130 nm, and the length is about 40 μm.

[0011] Further, the suitable coverage of the Au nanooctahedron on the surface of the Ag nanowire is 15-25%.

[0012] Further, the Au nanooctahedron has a uniform morphology, and the edge length size is 50-80 nm; for example, the edge length size of the Au nanooctahedron is 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm or 80 nm.

[0013] Ag nanowires with a diameter of 100-150 nm (e.g., 100 nm, 105 nm, 110 nm, 115 nm, 120 nm, 125 nm, 130 nm, 135 nm, 140 nm, 145 nm, or 150 nm) and a length of 20-50 μm (e.g., 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, or 50 μm); Au nanooctahedra with a suitable coverage on the surface of the Ag nanowires of 10-30% (e.g., 10%, 11%, 15%, 20%, 25%, 29%, or 30%); the working wavelength range of the metasurface wave absorber is 200-800 nm, and the average absorption rate of the metasurface wave absorber to incident light is >95% (e.g., 99% or 99.9%); the surface-enhanced Raman scattering detection enhancement factor of the metasurface wave absorber to 4-mercaptopyridine molecules (concentration of 1 x 10 - 5 mol / L) is 5-10 x 10 7 , and the detection concentration limit is 1 x 10 -11 mol / L.

[0014] Preferably, the Au nanooctahedra have a uniform morphology with a side length of about 75 nm; preferably, the Ag nanowires have a diameter of about 130 nm and a length of about 40 μm; preferably, the Au nanooctahedra have a suitable coverage on the surface of the Ag nanowires of 15-25%; preferably, the surface-enhanced Raman scattering detection enhancement factor of the metasurface wave absorber to 4-mercaptopyridine molecules (concentration of 1 x 10 -5 mol / L) is 6.4-9.1 x 10 7 , and the detection concentration limit is 1 x 10 -11 mol / L.

[0015] A method for preparing a metasurface wave absorber with surface-enhanced Raman scattering properties, comprising the following operation steps:

[0016] S1: Under ultrasonic oscillation conditions, Au nanooctahedra suspension is added dropwise into Ag nanowire suspension to form Au nanooctahedra hybrid Ag nanowire mixed solution; preferably, in the mixed solution, the mass ratio of Au nanooctahedra to Ag nanowires is 0.08-0.5 (e.g., 0.08, 0.09, 0.11, 0.13, 0.15, 0.2, 0.25, 0.3, 0.4, or 0.5);

[0017] S2: The Au nanooctahedra hybrid Ag nanowire mixed solution is dropped on the surface of a clean substrate, and then the substrate is placed horizontally in a thermostat. After the droplet is completely evaporated, the Au nanooctahedra hybrid Ag nanowires form a three-dimensional interlocking and interlaced structure state, and the preparation of the metasurface wave absorber with surface-enhanced Raman scattering properties is finally completed.

[0018] Further, the Au nanooctahedra are obtained by reducing chloroauric acid in pentanediol at 220-250 °C using ethylene glycol in the presence of poly(diallyldimethylammonium chloride) as a morphology control agent, wherein the molar ratio of poly(diallyldimethylammonium chloride) to chloroauric acid is 100-30 (e.g. 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35 or 30); the Ag nanowires are obtained by reducing silver nitrate at 150-180 °C using ethylene glycol in the presence of polyvinylpyrrolidone as a surfactant, wherein the molar ratio of polyvinylpyrrolidone to silver nitrate is 8-4 (e.g. 8, 7.5, 7, 6.5, 6, 5.5, 5, 4.5 or 4); preferably, the Au nanooctahedra are obtained by reducing chloroauric acid in pentanediol at 240 °C using ethylene glycol in the presence of poly(diallyldimethylammonium chloride) as a morphology control agent, wherein the molar ratio of poly(diallyldimethylammonium chloride) to chloroauric acid is 50:1; the Ag nanowires are obtained by reducing silver nitrate at 160 °C using ethylene glycol in the presence of polyvinylpyrrolidone as a surfactant, wherein the molar ratio of polyvinylpyrrolidone to silver nitrate is 5:1.

[0019] Further, the Au nanooctahedra suspension is a deionized water solution having a concentration of about 0.0005-0.0015 g / mL (e.g. 0.0005 g / mL, 0.0007 g / mL, 0.0009 g / mL, 0.001 g / mL, 0.0012 g / mL, 0.0014 g / mL or 0.0015 g / mL); the Ag nanowire suspension is also a deionized water solution having a concentration of about 0.003-0.008 g / mL (e.g. 0.003 g / mL, 0.004 g / mL, 0.005 g / mL, 0.006 g / mL, 0.007 g / mL or 0.008 g / mL).

[0020] Further, when preparing the Au nanooctahedra hybrid Ag nanowire mixture, the volume ratio of the amount of the Au nanooctahedra suspension to the amount of the Ag nanowire suspension is 0.5-5:1.5-3.3; the volume ratio of the amount of the Au nanooctahedra suspension to the amount of the Ag nanowire suspension can be 0.5:1.5-3.3, 0.7:1.5-3.3, 0.9:1.5-3.3, 1.5:1.5-3.3, 2:1.5-3.3, 2.5:1.5-3.3, 3:1.5-3.3, 3.5:1.5-3.3, 4:1.5-3.3, 4.5:1.5-3.3 or 5:1.5-3.3.

[0021] Further, when preparing the metasurface wave absorber, the amount of the Au nanooctahedra hybrid Ag nanowire mixture dropped on the substrate is 50-200 μL; preferably, the area of the substrate is 1-4 cm 2; preferably, the Au nanooctahedron suspension is a deionized water solution with a concentration of about 0.001 g / mL; the Ag nanowire suspension is also a deionized water solution with a concentration of about 0.005 g / mL. When the metasurface wave absorber is prepared, the amount of the Au nanooctahedron hybrid Ag nanowire mixed solution dropped on the substrate is 100 μL.

[0022] Further, in step S1, the Au nanooctahedron used is obtained by reducing chloroauric acid pentanediol solution at 240°C with ethylene glycol, under the action of poly diallyl dimethyl ammonium chloride morphology control agent, wherein the reaction molar ratio of poly diallyl dimethyl ammonium chloride to chloroauric acid is 50:1; the Ag nanowire is obtained by reducing silver nitrate at 160°C with polyvinylpyrrolidone as a surfactant, wherein the reaction molar ratio of polyvinylpyrrolidone to silver nitrate is 5:1.

[0023] Further, in step S2, the Au nanooctahedron suspension is a deionized water solution with a concentration of about 0.001 g / mL; the Ag nanowire suspension is also a deionized water solution with a concentration of about 0.005 g / mL; when the Au nanooctahedron hybrid Ag nanowire mixed solution is prepared, the dropping amount of the Au nanooctahedron is 1.5-3.3 mL. When the metasurface wave absorber is prepared, the amount of the Au nanooctahedron hybrid Ag nanowire mixed solution dropped on the substrate is 100 μL.

[0024] The beneficial effects of the present application are as follows:

[0025] The Au nanooctahedron hybrid Ag nanowire structure and related self-assembly technology are applied for the first time in the design and preparation of metasurface wave absorbers with surface-enhanced slow scattering characteristics; the working wavelength range of the metasurface wave absorber realized by the present application is widened to the ultraviolet-visible light wavelength range (200-800 nm), and the average light absorption efficiency is more than 95%; the metasurface wave absorber of the present application realizes high-sensitivity surface-enhanced Raman scattering detection response for 4-mercaptopyridine molecules (the enhancement factor and detection concentration limit reach 10 7 -11 mol / L, respectively); the present application provides certain reference for the design and preparation method of self-assembled metasurface wave absorbers in the research field, and is expected to be applied in the detection and analysis of trace substances related to SERS performance. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 : SEM image of the metasurface wave absorber when the Au nanooctahedron coverage is 20% in Example 1;

[0027] Figure 2 : Response of the metasurface wave absorber to 4-mercaptopyridine molecules (concentration 1×10 -5 ​SERS spectrum of (mol / L);

[0028] Figure 3 Example 1: When Au nano-octahedral coverage is 20%, the metasurface absorber effectively absorbs 4-mercaptopyridine molecules (concentration 1×10⁻⁶). -11 SERS spectrum of (mol / L);

[0029] Figure 4 Example 2: When the Au nano-octahedral coverage is 15%, the metasurface absorber effectively absorbs 4-mercaptopyridine molecules (concentration 1×10⁻⁶). -8 SERS spectrum of (mol / L);

[0030] Figure 5 Example 2: Light absorption curve of metasurface absorber with Au nano-octahedral coverage of 15%;

[0031] Figure 6 Example 3: SEM image of a metasurface absorber with 25% Au nano-octahedral coverage;

[0032] Figure 7 Example 3: When the Au nano-octahedral coverage is 25%, the metasurface absorber effectively absorbs 4-mercaptopyridine molecules (concentration 1×10⁻⁶). -5 SERS spectrum of (mol / L);

[0033] Figure 8 Example 4: Light absorption curve of metasurface absorber with Au nano-octahedral coverage of 18%;

[0034] Figure 9 Example 4: When the Au nano-octahedral coverage is 18%, the metasurface absorber effectively absorbs 4-mercaptopyridine molecules (concentration 1×10⁻⁶). -6 SERS spectrum of mol / L. Detailed Implementation

[0035] The present invention will be further described in conjunction with the following specific embodiments and accompanying drawings, but the scope of protection of the present invention is not limited to the following embodiments. Those skilled in the art can modify the following examples and apply the general principles to other examples without inventive effort. Therefore, all modifications and improvements made to the present invention by those skilled in the art based on the description provided are within the scope of protection of the present invention, and are protected by the appended claims.

[0036] In this invention, both the Au nano-octahedrons and Ag nanowires are self-made.

[0037] The preparation method of the Au nanooctahedron is as follows: firstly, 3 mL of ethylene glycol gold chloride solution (concentration of 0.02 mol / L) and 2.4 mL of polydiallyldimethylammonium chloride (molecular weight of about 450000) are sequentially added into a flask containing 50 mL of pentanediol, and stirring is continuously carried out at room temperature for about 2 min without sealing; then, the flask containing the above mixed solution is sealed and placed in a 240℃ oil bath for reflux reaction for 1 h; after the reaction is completed, the red-brown sample is centrifuged and washed (centrifuge speed of 12000 rpm, and deionized water is used as the washing solution). Finally, the obtained Au nanooctahedron sample is resuspended and dispersed in deionized water for subsequent experiments.

[0038] The preparation method of the Ag nanowire is as follows: firstly, 10 mL of ethylene glycol is introduced into a brown glass flask under continuous stirring, and then the flask is placed in a 160℃ oil bath for reflux for about 15 min; then, 5 mL of silver nitrate ethylene glycol solution (concentration of 0.06 mol / L) and 5 mL of polyvinylpyrrolidone (molecular weight of about 1300000) ethylene glycol solution (concentration of 0.3 mol / L) are added into the refluxing ethylene glycol solution at the same injection speed (1 mL / min), and the light gray Ag nanowire sample is generated after about 1 h of reaction; finally, the Ag nanowire sample is centrifuged and washed (centrifuge speed of 3000 rpm, and anhydrous ethanol is used as the washing solution), and the final sample is resuspended and dispersed in deionized water in the dark for subsequent experiments.

[0039] The coverage of the Au nanooctahedron attached to the surface of the Ag nanowire in the present application is obtained by software Nano-Measure analysis: specifically, the surface area S1 of a single Ag nanowire and the total area S2 of all Au nanooctahedrons attached to the single Ag nanowire are measured by the software respectively, and then the specific coverage is calculated by S2 / S1.

[0040] Example 1

[0041] Under ultrasonic oscillation, 2.5 mL of Au nanooctahedron water suspension (concentration of about 0.001 g / mL) is added dropwise into 2 mL of Ag nanowire water suspension (concentration of about 0.005 g / mL) to form an Au nanooctahedron hybrid Ag nanowire mixed solution. Then, 100 μL of the Au nanooctahedron hybrid Ag nanowire mixed solution is dropped on the surface of a clean substrate (substrate area of 3 cm 2 ), and then the substrate is horizontally placed in a 4℃ constant temperature box. After the droplet is completely evaporated, an Au nanooctahedron coverage of about 20% of the metasurface wave absorber is obtained, and the structure and optical properties of the metasurface wave absorber are tested and characterized.

[0042] Example 2

[0043] Under the condition of ultrasonic oscillation, 1.5 mL of Au nanooctahedron water suspension (concentration ~ 0.0006 g / mL) was added dropwise into 2 mL of Ag nanowire water suspension (concentration ~ 0.005 g / mL) to form Au nanooctahedron hybrid Ag nanowire mixture. Subsequently, 100 μL of Au nanooctahedron hybrid Ag nanowire mixture was dropped on the surface of a clean substrate (substrate area 3 cm 2 ), and then the substrate was horizontally placed in a 4°C incubator. After the liquid drop was completely evaporated, an ultrathin surface wave absorber with Au nanooctahedron coverage of about 15% was obtained, and the structure and optical properties of the ultrathin surface wave absorber were tested and characterized.

[0044] Example 3

[0045] Under the condition of ultrasonic oscillation, 3.3 mL of Au nanooctahedron water suspension (concentration ~ 0.0013 g / mL) was added dropwise into 2 mL of Ag nanowire water suspension (concentration ~ 0.005 g / mL) to form Au nanooctahedron hybrid Ag nanowire mixture. Subsequently, 100 μL of Au nanooctahedron hybrid Ag nanowire mixture was dropped on the surface of a clean substrate (substrate area 3 cm 2 ), and then the substrate was horizontally placed in a 4°C incubator. After the liquid drop was completely evaporated, an ultrathin surface wave absorber with Au nanooctahedron coverage of about 25% was obtained, and the structure and optical properties of the ultrathin surface wave absorber were tested and characterized.

[0046] Example 4

[0047] Under the condition of ultrasonic oscillation, 2 mL of Au nanooctahedron water suspension (concentration ~ 0.0008 g / mL) was added dropwise into 2 mL of Ag nanowire water suspension (concentration ~ 0.005 g / mL) to form Au nanooctahedron hybrid Ag nanowire mixture. Subsequently, 100 μL of Au nanooctahedron hybrid Ag nanowire mixture was dropped on the surface of a clean substrate (substrate area 3 cm 2 ), and then the substrate was horizontally placed in a 4°C incubator. After the liquid drop was completely evaporated, an ultrathin surface wave absorber with Au nanooctahedron coverage of about 18% was obtained, and the structure and optical properties of the ultrathin surface wave absorber were tested and characterized.

[0048] Comparative Example 1

[0049] Under the condition of ultrasonic oscillation, 0.7 mL of Au nanooctahedron water suspension (concentration ~ 0.00028 g / mL) was added dropwise into 2 mL of Ag nanowire water suspension (concentration ~ 0.005 g / mL) to form Au nanooctahedron hybrid Ag nanowire mixture. Subsequently, 100 μL of Au nanooctahedron hybrid Ag nanowire mixture was dropped on the surface of a clean substrate (substrate area 3 cm 2), and then the substrate was placed horizontally in a 4 °C incubator. After the droplet was completely evaporated, the super surface wave absorber with an Au nanooctahedron coverage of about 8% was obtained, and the structure and optical properties of the super surface wave absorber were tested and characterized.

[0050] Comparative Example 2

[0051] Under ultrasonic oscillation conditions, 0.3 mL of an Au nanooctahedron water suspension (concentration ~ 0.00012 g / mL) was added dropwise into 2 mL of an Ag nanowire water suspension (concentration ~ 0.005 g / mL) to form an Au nanooctahedron hybrid Ag nanowire mixture. Subsequently, 100 μL of the Au nanooctahedron hybrid Ag nanowire mixture was dropped onto the surface of a clean substrate (substrate area 3 cm 2 ), and then the substrate was placed horizontally in a 4 °C incubator. After the droplet was completely evaporated, the super surface wave absorber with an Au nanooctahedron coverage of about 8% was obtained, and the structure and optical properties of the super surface wave absorber were tested and characterized.

[0052] Comparative Example 3

[0053] 100 μL of an Au nanooctahedron water suspension (concentration ~ 0.001 g / mL) was dropped onto the surface of a clean substrate (substrate area 3 cm 2 ), and then the substrate was placed horizontally in a 4 °C incubator. After the droplet was completely evaporated, the Au nanooctahedron film layer was obtained, and the structure and optical properties of the film layer were tested and characterized.

[0054] Comparative Example 4

[0055] 100 μL of an Ag nanowire water suspension (concentration ~ 0.005 g / mL) was dropped onto the surface of a clean substrate (substrate area 3 cm 2 ), and then the substrate was placed horizontally in a 4 °C incubator. After the droplet was completely evaporated, the Ag nanowire film layer was obtained, and the structure and optical properties of the film layer were tested and characterized.

[0056] Note: The optical absorption properties of all the example and comparative example samples were completed on an ultraviolet-visible-near infrared spectrophotometer (Lambda 1050, PerkinElmer), the test wavelength band was 200-800 nm, the step size was set to 1 nm, and the light incidence mode was selected to be normal incidence; the SERS properties of all the example and comparative example samples were completed on a micro-Raman spectrometer (Horiba LabRamanHR Evolution), the laser excitation wavelength was 785 nm, the laser energy was 0.2 mW, the focusing time was 1 s, 4-mercaptopyridine was used as the detection molecule, and a deionized water solution with a concentration of 1 x 10 -5 ~ 1 x 10 -11 mol / L was prepared.

[0057] Table 1: Optical properties of the samples prepared in the examples and the control example of the present application

[0058] Sample name Average light absorption efficiency SERS enhancement factor SERS detection concentration limit Test wavelength range Example 1 96.7％ 9.1 x 10 7 ]]> 1 x 10 -11 mol / L 200-800 nm Example 2 95.2％ 6.4 x 10 7 ]]> 1 x 10 -10 mol / L 200-800 nm Example 3 96.3％ 7.6 x 10 7 ]] 1 x 10 -11 mol / L 200-800 nm Example 4 95.8％ 8.3 x 10 7 ]] 1 x 10 -11 mol / L 200-800 nm Comparative Example 1 93.5％ 2.3 x 10 7 ]]> 1 x 10 -9 mol / L 200-800 nm Comparative Example 2 90.6％ 8.5 x 10 6 ]]> 1 x 10 -8 mol / L 200-800 nm Comparative Example 3 37.8％ 4.2 x 10 6 ]]> 1 x 10 -7 mol / L 200-800 nm Comparative Example 4 88.6％ 2.6 x 10 6 ]]> 1 x 10"7mol / L 200-800 nm

[0059] Figure 1 is a typical SEM image of the metasurface wave absorber prepared in Example 1 of the present application. It can be seen that the Au nanooctahedra are randomly oriented and attached to the surface of the Ag nanowires in a hybrid structure (three-dimensional interlaced and staggered) with a coverage of about 20%;

[0060] Figure 2 is a typical SERS performance test image (analysis of the enhancement factor) of the metasurface wave absorber prepared in Example 1 of the present application. In this test, 4-mercaptopyridine (concentration of 1 x 10 -5 mol / L) was selected as the detection molecule, and the excitation laser wavelength was 785 nm. It can be seen that the Raman spectrum measured intensity reached about 3300 at the wave number of 1098 cm -1 , and the calculated SERS enhancement factor was about 9.1 x 10 7 ;

[0061] Figure 3 is a typical SERS performance test image (analysis of the detection limit) of the metasurface wave absorber prepared in Example 1 of the present application. In this test, 4-mercaptopyridine (concentration of 1 x 10 -11 mol / L) was selected as the detection molecule, and the excitation laser wavelength was 785 nm. It can be seen that the Raman spectrum measured intensity was about 140 at the wave number of 1098 cm -1 , and the Raman signal could be distinguished;

[0062] Figure 4 is a typical SERS performance test image (analysis of the detection limit) of the metasurface wave absorber prepared in Example 2 of the present application. In this test, 4-mercaptopyridine (concentration of 1 x 10 -8 mol / L) was selected as the detection molecule, and the excitation laser wavelength was 785 nm. It can be seen that the Raman spectrum measured intensity reached about 310 at the wave number of 1098 cm -1 , and the Raman signal could be distinguished;

[0063] Figure 5 is a typical absorption spectrum of the metasurface wave absorber prepared in Example 2 of the present application. It can be seen that the average light absorption rate of the metasurface wave absorber in the wavelength range of 200-800 nm was about 95.2%, and there were light absorption peaks near the wavelengths of 239 nm and 316 nm;

[0064] Figure 6is a typical SEM image of the super surface wave absorber prepared by the embodiment 3 of the present application. It can be seen that the Au nano-octahedron is randomly oriented and attached to the surface of the Ag nanowire in a hybrid structure (three-dimensional interlaced, staggered) with a coverage of about 25%.

[0065] Figure 7 is a typical SERS performance test image (analysis of enhancement factor) of the super surface wave absorber prepared by the embodiment 3 of the present application. In the test, 4-mercaptopyridine (concentration of 1×10 -5 mol / L) is selected as the detection molecule, and the excitation laser wavelength is 785 nm. It can be seen that the corresponding wave number 1098 cm -1 , the measured intensity of the Raman spectrum reaches about 2700, and the calculated SERS enhancement factor is about 7.6×10 7 .

[0066] Figure 8 is a typical absorption spectrum of the super surface wave absorber prepared by the embodiment 4 of the present application. It can be seen that the average light absorption rate of the super surface wave absorber in the wave band of 200-800 nm is about 95.8%, and there are light absorption peaks near the wavelengths of 235 nm and 310 nm.

[0067] Figure 9 is a typical SERS performance test image (analysis of detection limit) of the super surface wave absorber prepared by the embodiment 4 of the present application. In the test, 4-mercaptopyridine (concentration of 1×10 -6 mol / L) is selected as the detection molecule, and the excitation laser wavelength is 785 nm. It can be seen that the corresponding wave number 1098 cm -1 , the measured intensity of the Raman spectrum reaches about 600, and the Raman signal can be distinguished.

[0068] The part of the present application not described in detail belongs to the known technology of those skilled in the art. The above-described embodiments only describe the preferred embodiments of the present application, and the preferred embodiments do not describe all the details and limit the application to the specific embodiments described. Without departing from the design spirit of the present application, various modifications and improvements of the technical solutions of the present application made by those skilled in the art shall fall within the protection scope of the claims of the present application.

Claims

1. A method for preparing a metasurface wave absorber with surface-enhanced Raman scattering characteristics, characterized in that: The super surface wave absorber comprises Au nano-octahedron hybrid Ag nanowire structure; wherein the Au nano-octahedron is attached to the surface of the Ag nanowire in a random orientation and suitable coverage, and the formed hybrid structure presents a three-dimensional interlaced and staggered state; the super surface wave absorber has a broadband absorption optical performance in the ultraviolet-visible light waveband, and the super surface wave absorber has surface enhanced Raman scattering characteristics for 4-mercapto pyridine molecules; The Au nano-octahedron has a uniform morphology, and the edge length size is 50-80 nm; the Ag nanowire has a diameter of 100-145 nm and a length of 20-50 μm; the suitable coverage of the Au nano-octahedron on the surface of the Ag nanowire is 10-30%, and the working waveband of the super surface wave absorber is located in the wavelength range of 200-800 nm, and the average absorption rate of the super surface wave absorber to incident light is >95%; The method comprises the following operation steps: S1: under ultrasonic oscillation conditions, Au nano-octahedron suspension is added dropwise into Ag nanowire suspension to form Au nano-octahedron hybrid Ag nanowire mixed solution; the mass ratio of Ag nanowire is 0.08-0.5; S2: the Au nano-octahedron hybrid Ag nanowire mixed solution is dropped on the surface of a clean substrate, and then the substrate is horizontally placed in a thermostat; After the droplet is completely evaporated, the Au nano-octahedron hybrid Ag nanowire forms a three-dimensional interlaced and staggered structure state, and finally the preparation of the super surface wave absorber with surface enhanced Raman scattering characteristics is completed; The Au nano-octahedron is obtained by reducing chloroauric acid pentanediol solution at 220-250℃ using poly diallyl dimethyl ammonium chloride morphology control agent, wherein the reaction molar ratio of poly diallyl dimethyl ammonium chloride to chloroauric acid is 100-30; the Ag nanowire is obtained by reducing silver nitrate at 150-180℃ using polyvinylpyrrolidone as a surfactant, wherein the molar ratio of polyvinylpyrrolidone to silver nitrate is 8-4.

2. The method of claim 1, wherein: The surface-enhanced Raman scattering detection enhancement factor of the metasurface wave absorber on 4-mercaptopyridine molecules is 5~10×10 7 , and the detection concentration limit is 1×10 -11 mol / L.

3. The method of claim 1, wherein: The Au nano-octahedron suspension is a deionized water solution, and the concentration is 0.0005-0.0015 g / mL; the Ag nanowire suspension is a deionized water solution, and the concentration is 0.003-0.008 g / mL.

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