Gold nanoparticle hollow frustum array surface-enhanced Raman scattering substrate and detection method

Abstract

This invention discloses a gold nanoparticle hollow frustum array surface-enhanced Raman scattering substrate and detection method, solving the technical problems of existing gold nanoparticle array surface-enhanced Raman scattering substrates lacking hollow frustum structures, resulting in a narrow Raman spectroscopy detection wavelength range and low detection resolution. This invention includes a substrate and several gold nanoparticle hollow frustums on the substrate. The height of the gold nanoparticle hollow frustums is 800-1200 nm, the top outer diameter is 120-180 nm, the bottom outer diameter is 350-450 nm, the thickness is 30-50 nm, and the density is 1-3 frustums / μm. 2 The invention discloses the use of this gold nanoparticle hollow frustum array for Raman detection and analysis of organic compounds. This invention offers advantages such as higher detection sensitivity for organic analysis and a wider detection wavelength range.

Description

Technical Field

[0001] This invention relates to the field of nano-optics technology, specifically to a gold nano-hollow frustum array surface-enhanced Raman scattering substrate and detection method. Background Technology

[0002] Raman scattering spectroscopy gives molecules "fingerprints," which has aroused special research interest in the fields of molecular sensing and biology.

[0003] Compared to conventional Raman spectroscopy, surface-enhanced Raman scattering (SERS) spectroscopy offers significantly higher detection sensitivity, and has therefore gained rapid attention in the study of biomolecules adsorbed on metal surfaces. SERS spectroscopy enables the detection and analysis of trace analytes because it achieves substantial scattering enhancement in the subwavelength molecular range to obtain high-quality SERS spectra.

[0004] The enhancement mechanism of SERS can be partly attributed to the huge localized electromagnetic field generated by resonant surface plasmons, which can be excited by light of specific wavelengths on metal particles of different shapes or closely packed particle groups. Aggregates of interacting particles can be excited by plasmon resonances across a very broad spectral range. In addition to electromagnetic field enhancement, metal nanostructures and molecules can form charge-transfer complexes, further enhancing SERS. The resulting overall enhancement is critically dependent on the morphology of the particles or aggregated nanostructures.

[0005] Based on the current nanostructure morphology, surface-enhanced Raman scattering spectroscopy has improved detection sensitivity to some extent, but further broadening the detection wavelength range and improving detection resolution remain long-standing technical challenges in this field. Summary of the Invention

[0006] The technical problem to be solved by this invention is that existing gold nanoarray surface-enhanced Raman scattering substrates lack hollow frustum structures, resulting in a narrow Raman spectroscopy detection wavelength range and low detection resolution.

[0007] This invention is achieved through the following technical solution:

[0008] A surface-enhanced Raman scattering substrate comprising a gold nanoparticle hollow frustum array structure includes a substrate and a plurality of gold nanoparticle hollow frustums on the substrate. The dimensions of the gold nanoparticle hollow frustums gradually increase from top to bottom. The height of each gold nanoparticle hollow frustum is 800-1200 nm, the outer diameter of the top is 120-180 nm, the outer diameter of the bottom is 350-450 nm, the thickness is 30-50 nm, and the density is 1-3 frustums / μm. 2 .

[0009] This invention develops a novel surface-enhanced Raman scattering substrate, which is composed of several gold nano-hollow frustums. It possesses the shape characteristics of several structures, including cylinders, rings, and cones, and is a hollow frustum that is smaller at the top and larger at the bottom. Its morphology is uniform, and it has a strong focusing ability for light intensity, which can be used for Raman spectroscopy detection.

[0010] The present invention preferably provides a surface-enhanced Raman scattering substrate with a gold nano-hollow frustum array structure, wherein the plurality of gold nano-hollow frustums are uniformly distributed on the substrate and arranged in parallel on the same plane.

[0011] The present invention preferably provides a surface-enhanced Raman scattering substrate with a gold nano-hollow frustum array structure. The substrate includes an upper gold film and a copper film below the gold film. The plurality of gold nano-hollow frustums are uniformly distributed on the gold film, and the thickness of the copper film is 10-20 μm.

[0012] The Raman spectroscopy detection method based on the gold nanoparticle hollow frustum array structure includes the following steps:

[0013] Step 1: Fabricate a gold nano-hollow frustum array structure surface-enhanced Raman scattering substrate sample;

[0014] Step 2: Analyze the optical properties of the sample using a near-field scanning optical microscope;

[0015] Step 3: Prepare organic solutions of different concentrations and drop the organic solutions of different concentrations onto the substrate sample prepared in Step 1;

[0016] Step 4: Use a Raman spectrometer to test the spectral data of the substrate sample under different concentrations of organic solutions;

[0017] Step 5: Analyze the spectral data obtained in Step 4 to obtain the detection function of the substrate sample for organic solutions of different concentrations.

[0018] Furthermore, in step 1, the method for preparing the gold nanoparticle hollow frustum array structure surface-enhanced Raman scattering substrate sample is as follows:

[0019] S1: Template preparation;

[0020] S2: The template is asymmetrically etched to obtain a template with tapered nanopores;

[0021] S3: Sputter gold into the conical nanopores in step S2;

[0022] S4: Deposit copper onto a template and a gold-sputtered conical nanopore to obtain a gold-coated copper substrate with a frustum, wherein the copper substrate has a frustum.

[0023] S5: Peel the copper substrate from the template in step S4 and plate gold again in the conical nanopores. Repeat this process multiple times to obtain the gold nano hollow frustum array structure.

[0024] Further, in step S1, using 209 Bi 31+ Ions at 9.5 MeV u -1 The initial kinetic energy was used to irradiate a 30 mm thick polycarbonate foil to obtain a template with ion tracks.

[0025] Furthermore, in step S2, the etchant used is a mixed aqueous solution of methanol and sodium hydroxide.

[0026] The preferred method of this invention is a Raman spectroscopy detection method based on a gold nano-hollow frustum array structure, wherein the organic solution is a Rhodamine 6G solution.

[0027] The preferred Raman spectroscopy detection method of this invention is based on a gold nanoparticle hollow frustum array structure, wherein the concentration of the Rhodamine 6G solution is 10. -6 mol / L, 10 -8 mol / L and 10 -12 mol / L.

[0028] This invention prepares three different concentrations of Rhodamine 6G solution to test the advantages of the above-mentioned gold nanoparticle hollow frustum array structure surface-enhanced Raman scattering substrate in terms of sensitivity and resolution for detecting organic molecules.

[0029] The preferred Raman spectroscopy detection method of the present invention based on a gold nano hollow frustum array structure includes the following steps: In step 3, an organic solution of a certain concentration is dropped onto the substrate sample and then air-dried. In step 4, after the spectral data is measured, the substrate sample is cleaned with alcohol and dried. Then, the operation is repeated twice with two other concentrations of organic solution.

[0030] The present invention has the following advantages and beneficial effects:

[0031] 1. The gold nano-hollow frustum array structure surface-enhanced Raman scattering substrate of the present invention has a hollow frustum array structure with uniform morphology and size, and has shape characteristics of several structures such as cylinder, ring and cone. It is a novel morphology that can be used for Raman spectroscopy analysis.

[0032] 2. This invention analyzes the optical properties of the surface-enhanced Raman scattering substrate of the gold nano-hollow frustum array structure using near-field scanning optical microscopy. The analysis shows that the substrate has a strong focusing ability for light intensity and can be used for Raman spectroscopy detection.

[0033] 3. This invention enables the spectral analysis of solutions with different concentrations of Rhodamine 6G by preparing solutions of different concentrations and using a surface-enhanced Raman scattering substrate with a gold nano-hollow frustum array structure to perform Raman spectral analysis on solutions of different concentrations, demonstrating high sensitivity.

[0034] 4. Compared with traditional Raman spectroscopy detection substrates, this invention has higher detection sensitivity and the ability to detect a wider wavelength range. The substrate is composed of high-density gold nano-hollow frustum structures, which allows for more convenient and rapid detection of light waves of various wavelengths.

[0035] 5. The substrate based on a gold nano-hollow frustum array structure provided by this invention exhibits broadband response and efficient plasmonic near-field enhancement, making it suitable for optical focusing and enabling the analysis of light intensity variations over a wide wavelength range. It holds significant importance in fields such as Raman spectroscopy detection and nanoscale optical manipulation. Attached Figure Description

[0036] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0037] Figure 1 These are SEM images of the surface-enhanced Raman scattering substrate of the gold nano hollow frustum array structure of the present invention at different magnifications, where (a) is an SEM image magnified 10,000 times and (b) is an SEM image magnified 30,000 times.

[0038] Figure 2 These are near-field scanning optical microscope images of a gold nano-hollow frustum array structure surface-enhanced Raman scattering substrate, where 2(a) is a two-dimensional image and 2(b) is a three-dimensional image.

[0039] Figure 3 It is based on the surface-enhanced Raman scattering substrate of gold nanohollow frustum array structure for a concentration of 10 -6 Raman spectrum of 6 mol / L rhodamine 6G solution.

[0040] Figure 4 It is based on the surface-enhanced Raman scattering substrate of gold nanohollow frustum array structure for a concentration of 10 -8 Raman spectrum of 6 mol / L rhodamine 6G solution.

[0041] Figure 5 It is based on the surface-enhanced Raman scattering substrate of gold nanohollow frustum array structure for a concentration of 10 -12 Raman spectrum of 6 mol / L rhodamine 6G solution. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0043] Example 1

[0044] The surface-enhanced Raman scattering substrate of gold nano-hollow frustum array structure comprises two parts. The upper part consists of multiple gold nano-hollow frustum structures arranged in parallel on the same plane and uniformly distributed on a gold thin film. The lower part is a copper thin film.

[0045] The gold nano-hollow frustum gradually increases in size from top to bottom. In this embodiment, the height of the gold nano-hollow frustum structure is 900-1100 nm, the outer diameter of the top is 150-160 nm, the outer diameter of the bottom is 380-420 nm, the thickness is 35-45 nm, and the density is 1-3 frustums / μm. 2 The thickness of the copper film is 15 μm.

[0046] The method for preparing a gold nanoparticle hollow frustum array structure surface-enhanced Raman scattering substrate is as follows:

[0047] S1: Prepare template, using 209 Bi 31+ Ions at 9.5 MeV u -1 The initial kinetic energy was used to irradiate a 32 mm thick polycarbonate foil to obtain a template with ion tracks;

[0048] S2: The template is asymmetrically etched to obtain a template with conical nanopores. The etching agent used is a mixed aqueous solution of methanol and sodium hydroxide, wherein the concentration of sodium hydroxide is 10% and the volume ratio of methanol to sodium hydroxide is 99:1. The template is rinsed with deionized water within 30 seconds after etching to remove residual etching agent. Then, the template is allowed to air dry naturally.

[0049] S3: Sputter gold into the conical nanopores of step S2. The sputtering current is 12mA and the sputtering time for each sample is 240 seconds.

[0050] S4: Copper is deposited onto a gold-sputtered conical nanopore and a template to obtain a gold-coated copper substrate with a frustum. The copper thickness is about 15 μm. The deposition temperature is 20-22℃ at room temperature, the deposition voltage is 0.7V, and the deposition time is 35 min.

[0051] S5: Peel the copper substrate from the template in step S4 and plate gold again in the conical nanopores. Repeat this process multiple times to obtain a gold nano-hollow frustum array structure, such as... Figure 1 As shown.

[0052] The Raman spectroscopy detection method based on the gold nanoparticle hollow frustum array structure includes the following steps:

[0053] Step 1: Analyze the optical properties of the prepared gold nano-hollow frustum array structure surface-enhanced Raman scattering substrate sample using near-field scanning optical microscopy;

[0054] The substrate was fixed onto a glass slide and then placed on the scanning stage of a near-field scanning optical microscope. The microscope was then turned on to perform a near-field scan of the structure. The scanning results in this embodiment are as follows: Figure 2 As shown.

[0055] from Figure 2 The scanning results show that the uniformly distributed planar light is focused into multiple bright spots, which facilitates optical detection. The substrate of the gold nano hollow frustum array metasurface structure has a strong focusing ability for light, which indicates that the substrate can be used for Raman spectroscopy detection.

[0056] Step 2: Prepare solutions of Rhodamine 6G at different concentrations, drop the Rhodamine 6G solutions onto the substrate sample, and use a Raman spectrometer to test the spectral data of the sample under different concentrations of Rhodamine 6G solutions.

[0057] Configured with 10 -6 mol / L, 10 -8 mol / L and 10 -12 Three concentrations of Rhodamine 6G solutions (10⁻⁴ mol / L) were prepared. A 10⁻⁴ mol / L Rhodamine 6G solution was dropped onto a gold nanoparticle hollow frustum array substrate. After air drying, Raman spectra were measured using a Raman spectrometer. After measurement, the substrate was cleaned with alcohol and dried. This process was repeated twice with the other two concentrations of Rhodamine 6G solutions.

[0058] Step 3: Analyze the spectral data to obtain the detection function of the substrate sample for different concentrations of Rhodamine 6G solution.

[0059] The Raman spectra of the three concentrations of Rhodamine 6G solutions obtained are as follows: Figures 3-5 As shown.

[0060] analyze Figures 3-5 The Raman spectrum shows that this invention can perform spectral analysis on solutions with low solubility, and can detect up to 10... -12 Raman spectroscopy was performed on a mol / L Rhodamine 6G solution to infer the molecular components contained in the solution from the spectrum, providing a more accurate and effective method for the detection of organic components.

[0061] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A surface-enhanced Raman scattering substrate with a gold nano-hollow frustum array structure, characterized in that, The system comprises a substrate and several gold nanotube hollow frustums on the substrate. The dimensions of the gold nanotube hollow frustums gradually increase from top to bottom. The height of each frustum is 800-1200 nm, the outer diameter of the top is 120-180 nm, the outer diameter of the bottom is 350-450 nm, the thickness is 30-50 nm, and the density is 1-3 frustums / μm. 2 , The substrate was prepared using the following method: S1: Prepare a template, wherein the template is a polycarbonate foil with ion tracks after being irradiated by ions; S2: The template is asymmetrically etched to obtain a template with tapered nanopores; S3: Sputter gold into the conical nanopores in step S2; S4: Copper substrate with frustum coated with gold is obtained by depositing copper on a template through a gold-sputtered conical nanopore. S5: Peel the copper substrate from the template in step S4 and plate gold again in the conical nanopores. Repeat this process multiple times to obtain the gold nano hollow frustum array structure.

2. The surface-enhanced Raman scattering substrate of a gold nano-hollow frustum array structure according to claim 1, characterized in that, The plurality of gold nano-hollow frustums are uniformly distributed on the substrate and arranged in parallel on the same plane.

3. A surface-enhanced Raman scattering substrate for a gold nano-hollow frustum array structure according to claim 1 or 2, characterized in that, The substrate is a copper thin film with a thickness of 10-20 μm.

4. A Raman spectroscopy detection method based on a gold nanoparticle hollow frustum array structure, characterized in that, Includes the following steps: Step 1: Prepare a surface-enhanced Raman scattering substrate sample with a gold nano-hollow frustum array structure as described in any one of claims 1-3; Step 2: Analyze the optical properties of the sample using a near-field scanning optical microscope; Step 3: Based on the optical properties obtained in Step 2, prepare organic solutions of different concentrations and drop the organic solutions of different concentrations onto the substrate sample prepared in Step 1. Step 4: Use a Raman spectrometer to test the spectral data of the substrate sample under different concentrations of organic solutions; Step 5: Analyze the spectral data obtained in Step 4 to obtain the detection function of the substrate sample for organic solutions of different concentrations.

5. The Raman spectroscopy detection method based on a gold nano-hollow frustum array structure according to claim 4, characterized in that, The organic solution is a Rhodamine 6G solution.

6. The Raman spectroscopy detection method based on a gold nano-hollow frustum array structure according to claim 5, characterized in that, The concentration of the Rhodamine 6G solution is 10. -6 mol / L, 10 -8 mol / L and 10 -12 mol / L.

7. The Raman spectroscopy detection method based on a gold nano-hollow frustum array structure according to claim 6, characterized in that, In step 3, an organic solution of a certain concentration is dropped onto the substrate sample and then air-dried. In step 4, after the spectral data is measured, the substrate sample is cleaned with alcohol and dried. The process is then repeated twice with two other concentrations of organic solution.

Images