Recently, the State Key Laboratory of Applied Optics of the Changchun Institute of Optics, Chinese Academy of Sciences has used the lyotropic liquid crystal soft template for the first time in the world to controllably grow a large area of ​​uniform and highly active surface Raman scattering enhanced substrate, and the enhancement factor has reached the international advanced level. Related results were published in the recent Scientific Reports.
Surface Raman scattering enhancement is a technique that can significantly increase the sensitivity of Raman spectroscopy. Usually, rare metal nanostructures are used to prepare surface Raman scattering enhanced substrates, but there are currently many preparation methods such as etching and seed growth. Laws and various chemical deposition methods are not ideal. There is no systematic solution to the problems of long time, poor repeatability, high costs, and uncontrollable issues. Therefore, the development of a new simple low-cost controllable growth method has important application value for the development of surface Raman scattering technology.
This work utilizes the three-phase lyotropic liquid crystal soft template combined with the synergistic self-assembly growth principle to controllably prepare a large-area uniform nano-silver surface scattering enhanced substrate. The sodium succinate, paraxylene and silver nitrate solution were mixed according to the three-phase diagram. The phase separation occurred at the appropriate temperature. The hydrophilic side of the sodium succinate molecule was brought close together and the silver nitrate solution was confined to it. The hydrophobic end was outward. Combined with paraxylene. The localized silver ions at the hydrophilic end crystallize and nucleate during the electrochemical deposition process, gradually grow up, eventually breaking the bond of the liquid crystal soft template, and growing into a flower-shaped structure under the synergy of the self-assembly effect.
The nanostructures have more tips and crevices and can form a large number of "hot spots" to achieve enhanced Raman scattering and enhanced fluorescence. The method has the advantages of simple process, low cost, repeated model, controllable morphology, and easy growth over a large area, and provides a new research idea for surface Raman scattering enhancement and preparation of a fluorescence enhanced substrate, and can be widely used in food safety, Environmental protection, biochemical testing and other fields have laid the foundation for mass industrial production. The research work was supported by funds from the National Natural Science Foundation and other projects. (Li Rong reporter Zhang Zhaojun)
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