Preparation method for nano gold-silver composite material substrate of core-shell structure

Abstract

The invention relates to a preparation method for a nano gold-silver composite material substrate of a core-shell structure, and belongs to the technical field of surface-enhanced Raman scattering (SERS). The preparation method comprises the following steps that HAuCl4 is reduced into elemental gold by using Na3C6H5O72H2O by means of a hydrothermal reduction method, and cleaning and dispersing are conducted to obtain Au seed solutions; the Au seed solutions, Na3C6H5O72H2O solutions and ascorbic acid solutions are added into deionized water, uniformly stirred, and subjected to a water bath at 40 DEG C for 15 minutes; silver nitrate solutions are added dropwise at a constant speed, continuously stirred, and subjected to a water bath at 40 DEG C for 30-40 minutes; nano gold-silver composite material sol of a core-shell structure is obtained after cleaning; and the sol is dripped on a clean silicon wafer and covers the surface of the silicon wafer, vacuum drying is performed, and the substrate is prepared. According to the preparation method, the problem of remarkable anisotropism of single noble metal nanoparticles is greatly solved; and the SERS signal on the substrate is greatly enhanced, and the lowest detection limit of the substrate is 109M.

Description

technical field [0001] The invention relates to a preparation method of a nano-gold-silver composite material substrate with a core-shell structure, and belongs to the technical field of surface-enhanced Raman scattering (SERS). Background technique [0002] Surface-enhanced Raman scattering (SERS) technology is a special optical phenomenon at the nanometer scale, and it is an important tool for studying the molecular structure and microscopic properties of materials. However, three major obstacles were encountered in the course of its development: [0003] 1) Only precious metals such as gold (Au), silver (Ag) and copper (Cu) or the surface of corresponding sol particles and a few alkali metals have a strong SERS effect; [0004] 2) It is difficult to prepare a rough surface with good stability and reproducibility; [0005] 3) The enhancement mechanism of SERS is relatively complicated, and there has been great controversy about its theoretical research. [0006] Therefo...

AI Technical Summary

Problems solved by technology

[0004] 2) It is difficult to prepare a rough surface with good stability and reproducibility;

[0005] 3) The SERS enhancement mechanism is relatively complex, and there has been great controversy about its theoretical research

Tran Thi Bich Quyen et al. synthesized Ag / Au / Pt NPs (nanoparticles) by means of electro-displacement. Through the interaction of three elements, excitation with an excitation wavelength matching the ultraviolet absorption wavelength can significantly enhance SERS signal, but these methods have the disadvantages of low stability and reproducibility, and difficulty in controlling the core-shell thickness

Wang Lihua et al prepared Au@Ag nanoparticles by oil bath heating method, but the preparation process of this method is more complicated, and the oil bath heating is also more dangerous.

Images