Method for synthesizing shell isolation silver nanoparticles

Abstract

The invention discloses a method for synthesizing controllable shell isolation silver nanoparticles. According to the controllable shell isolation silver nanoparticles, the silver nanoparticles within the grain diameter ranging from 20 nm to 300 nm serve as inner cores and are coated with dense and even silicon dioxide shells, and the grain diameter of the silicon dioxide shells can be adjusted with the grain diameter ranging from 1 nm to 30 nm. The method includes the following steps that firstly, gold nanoparticles with the grain diameter ranging from 8 nm to 20 nm are synthesized; secondly, the silver nanoparticles with the grain diameter ranging from 20 nm to 300 nm are synthesized; thirdly, the surfaces of the silver nanoparticles synthesized in the second step are coated with the silicon dioxide shells with the grain diameter ranging from 1 nm to 30 nm. According to the silicon-dioxide-coated silver nanoparticles acquired through the method, the shells are composed of silicon diode with chemical inertness, electrics insulation and optically-transparent characteristics, and the silver nanoparticles are extremely thin and dense.

Description

technical field [0001] The invention relates to a shell coating method of silver nanoparticles with a core-shell structure, in particular to a synthesis methodology for isolating silver nanoparticles with an extremely thin shell. Background technique [0002] Since the end of the 20th century, nanotechnology has developed rapidly, and the research on surface plasmon resonance theory in nanoscience has become more and more in-depth. Nanoparticles of metals (gold, silver, copper) with different particle sizes and shapes have been widely studied. And as an active substrate for surface-enhanced Raman spectroscopy. In the traditional technology in the past, noble metal nanoparticles were deposited and assembled electrochemically or physically on the Raman spectrum substrate to obtain a strong electromagnetic field enhancement factor. Factors of information: (probe) molecular contact, solution contact, electronic contact. In 2010, Professor Tian Zhongqun’s research group propose...

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Problems solved by technology

However, in the traditional chemical synthesis, it is difficult to obtain silver nanoparticles with high uniformity in the absence of strong adsorption surface protection agents, and the strong adsorption surface protection agents are not conducive to the subsequent shell coating and electrochemical experiments

The silica silver-coated nanoparticles obtained by the existing methods have respectively incompact shells, poor monodispersity, strong adsorption of surfactants, etc., and because the experimental reaction period is long (usually more than one day), it is easy to be polluted by impurities in the air. , forming a thicker oxide / sulfide layer on the silver surface

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