| Launch：2019-08-13 |
Raman scattering effect is very weak, and its scattering light intensity is about 10-6~10-9 of the incident light intensity, which greatly limits the application and development of Raman spectrum. In 1974, Fleischmann et al. found that the Raman signal strength of tt molecules adsorped on the surface of rough gold and silver was greatly improved, and the signal strength changed with the change of the electrode potential. [5] in 1977,Jeanmaire, Van Duyne, Albrecht and Creighton et al. conducted systematic experimental research and theoretical calculation, so they called such enhanced effect related to rough surfaces such as silver, gold and copper Surface enhanced Raman Scattering, SERS, etc., so the corresponding spectrum is called Surface enhanced Raman spectrum. Subsequently, SERS phenomena were also observed on other rough surfaces. SERS technology developed rapidly and was widely used in the fields of analysis science, surface science and biological science, growing into a very powerful analytical tool. As for the nature of the enhancement mechanism, there is still no consensus in the academic circles. Most scholars believe that SERS enhancement mainly consists of physical enhancement and chemical enhancement, and the former is dominant, while the latter only contributes 1-2 orders of magnitude in the enhancement effect. Physical enhancement has no selectivity for the enhancement of molecules adsorbed near the substrate. A large number of experimental studies showed that the simple mechanism of physical or chemical enhancement was not enough to explain all SERS phenomenon, and the influencing factors of the enhancement process were very complex. In many systems, it was believed that the two factors may be acting simultaneously, and their relative contributions were different in different systems.
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