CN-118577787-B - Preparation method and application of patterned silver-coated Au@Ag nanostructure substrate

CN118577787BCN 118577787 BCN118577787 BCN 118577787BCN-118577787-B

Abstract

The invention belongs to the technical field of Raman substrates, and particularly relates to a preparation method and application of a patterned silver-coated gold Au@Ag nanostructure substrate. The patterned silver coated Au@Ag nanostructure substrate takes the patterned Au nanostructure with uniform particle size and compact stacking as a template to synthesize an Ag shell layer in situ, and Ag uniformly coats each Au nanoparticle to obtain a high-quality patterned silver coated Au@Ag core-shell nanostructure, no additional stabilizer is required to be introduced, no complicated experimental step flow is required, and the stable and general preparation of the SERS substrate with high sensitivity and high enhancement uniformity is provided for reference. Due to the synergistic effect of Au and Ag, the SERS effect of the substrate is enhanced, the Raman enhancement effect of the nanostructure is stronger than that of the patterned Au nanostructure, the Raman enhancement effect is more beneficial to detection and analysis of molecules, the problem that an Ag shell is easy to oxidize is avoided, and the Raman enhancement effect has good signal enhancement uniformity.

Inventors

HUANG ZHENKAI
PENG JIANPING

Assignees

佛山科学技术学院

Dates

Publication Date: 20260512
Application Date: 20240603

Claims (8)

1. The preparation method of the patterned silver-coated Au@Ag nanostructure substrate is characterized by comprising the following steps of: 1) Preparing a silicon wafer with a patterned Au nano structure; The patterned Au nanostructure is shown below: The lower end of the crystal is grown on a silicon wafer, wherein m and n are natural numbers; 2) Preparing patterned silver-coated Au@Ag nanostructure substrate And (3) under the inert gas atmosphere, adding the silicon wafer with the patterned Au nano structure in the step (1) into a mixed solution containing Ag + for soaking, then carrying out reaction at 80 ℃, taking out the silicon wafer after the reaction is released, carrying out ultrasonic treatment, cleaning to remove metal precipitate, and drying to obtain the substrate with the patterned silver-coated Au@Ag nano structure.
2. The method according to claim 1, wherein the mixed solution containing Ag + is a mixture of silver salt and an organic solution.
3. The preparation method according to claim 2, wherein the solid-to-liquid ratio of the silver salt to the organic solution is 1 (100-120) mg/mL.
4. The preparation method according to claim 2, wherein the organic solution comprises more than one of ethanol and DMF.
5. A patterned silver-coated au@ag nanostructure substrate obtained by the method of any one of claims 1 to 4, characterized in that it has nanoparticles with Ag as a shell layer and Au as a core, forming a patterned core-shell nanostructure with uniform particle size and close packing.
6. Use of a patterned silver-coated au@ag nanostructure substrate according to claim 5 for the preparation of SERS sensors.
7. Use of the patterned silver-coated au@ag nanostructure substrate of claim 5 for quantitative and qualitative detection of pesticide residues, wherein the pesticide residues comprise thiram.
8. Use of the patterned silver-coated au@ag nanostructure substrate of claim 5 in chemical dye detection; The chemical dyes include 4-AMTP, 4-MBA and methylene blue.

Description

Preparation method and application of patterned silver-coated Au@Ag nanostructure substrate Technical Field The invention belongs to the technical field of Raman substrates, and particularly relates to a preparation method and application of a patterned silver-coated gold Au@Ag nanostructure substrate. Background Surface Enhanced Raman Scattering (SERS), a highly sensitive non-destructive characterization technique, is widely used in trace detection, biological imaging, and compound analysis applications. With the continuous development of the nano material preparation technology and the continuous improvement of the signal detection system, the SERS detection technology is developed suddenly and rapidly, plays an indispensable role in a plurality of fields, and has good development prospect and wide application space. To date, SERS detection techniques have faced challenges such as stability of the structure and properties of SERS substrates. In the test environment, if the substrate structure and chemical properties are unstable, such as aggregation of particles in the nanoparticle substrate, oxidation of the metal surface in the metal nanostructure substrate, etc., the raman enhancement effect of the substrate is greatly impaired until the raman enhancement capability is completely lost. The Ag nano particle is a nano material with surface plasmons, and can show a strong Raman effect in an excitation light range with a wavelength of 300-1200 nm. However, ag nanoparticles are very unstable, the surface is easily oxidized, and the raman enhancement effect of the oxidized Ag nanoparticles is greatly reduced. Au has a very good raman enhancement effect at an excitation light of 632.8nm, whereas Au exhibits only a very weak raman enhancement effect when the excitation light becomes 514.2 nm. Except that Ag has a strong raman enhancement effect under different excitation light. Studies have shown that the plasmon resonance peaks of gold-silver bimetallic change with the change of the gold-silver composition because the plasmon resonance peaks of Au and Ag are different. In recent years, many methods have been tried to prepare bimetallic nanoparticles, such as a deposition-precipitation method, a seed-mediated method, a co-precipitation method, a displacement method, a template growth method, and the like. The synergy between the different noble metal nanoparticles makes these bimetallic nanoparticles with raman enhancement effect suitable for detection of a variety of illegal food additives, explosives, DNA chains, proteins and environmental pollutants. However, the introduction of surfactants has some effect on trace detection. The added active agent may become impurities or adsorb on the surface of the nanoparticle, affecting the sensitivity and signal reproducibility of the raman analysis. In addition, these preparation methods have difficulty in preparing raman substrates with uniformly distributed "hot spots" and poor uniformity of raman signals, which are unsuitable for practical analysis. Therefore, it is particularly critical to develop a simpler method of synthesizing a bimetallic SERS substrate that can produce synergistic, enhanced raman effects. Disclosure of Invention Aiming at the problems, the invention aims to provide a preparation method and application of a patterned silver-coated gold Au@Ag nanostructure substrate. The technical content of the invention is as follows: the invention provides a preparation method of a patterned silver-coated gold Au@Ag nanostructure substrate, which comprises the following steps: 1) Preparing a silicon wafer with a patterned Au nano structure; the Au nanostructures are shown below: the lower end grows on a silicon wafer, wherein m and n are natural numbers; 2) Preparing patterned silver-coated Au@Ag nanostructure substrate Under the inert gas atmosphere, adding the silicon wafer with the patterned Au nano structure in the step 1) into a mixed solution containing Ag + for soaking, then carrying out reaction at 80 ℃, taking out the silicon wafer after the reaction is released, carrying out ultrasonic treatment, cleaning to remove metal precipitate, and drying to obtain a substrate with the patterned silver-coated Au@Ag nano structure; The mixed solution containing Ag + is a mixture of silver salt and organic solution; the solid-liquid ratio of the silver salt to the organic solution is 1 (100-120) mg/mL; the organic solution comprises more than one of ethanol and DMF. In the mixed solution containing Ag +, the mixing proportion can be selected according to the thickness of the silver layer, and under different proportions, the more DMF is, the thicker the silver layer is. The preparation of the silicon wafer with the patterned Au nano-structure in the step 1) is as follows: 1.1 Silicon wafer surface grafting initiator The method comprises the steps of (1) treating and cleaning a silicon wafer by using a piranha solution (H 2O2:H2SO4 =3:7), soaking the silicon wa