The Study Of Surface-enhanced Raman Scattering Substrate Developed By Spin Self-assembly

The effective detection of trace elements in matter has always been a problem to be solved.The Raman Effect can form different characteristic peak in the Raman spectrum for different material,so that it can able to effectively detect the substance.The surface enhanced Raman scattering?SERS?was first discovered in 1974.After decades of the development of SERS substrate preparation and the study of enhancement mechanism,surface enhanced Raman scattering?SERS?technique has become a non-contact,high sensitivity,low cost,real-time technique.By combination of the spin self-assembly and vacuum ion sputtering,this paper proposes an improved SERS substrate preparation method.This method has the advantages of low cost,simple process and uniform preparation of large area.For different sizes of colloidal microspheres,effective control of the regulation of large area and the thickness of the coating can be achieved.The optimization of the coating gap and the size of Au microspheres make the enhancement effect reach more than 10⁷orders of magnitude.By means of scanning electron microscopy and other experimental methods,the mechanism of the optimized morphology has been analyzed.The results have been verified by FDTD simulation and Raman spectroscopy analysis.The SERS preparation methods and techniques of 200nm and 360nm polystyrene colloidal spheres by ion sputtering coating have been studied.The study finds that:1?In the process of ion sputtering,when gold film coating thickness is over 30nm,SERS substrate surface temperature will exceed PS glass transition temperature.Under the effect of the plastic deformation and the gravity of gold film,the point gap between polystyrene microspheres and microspheres evolves into about 10 nm line gap?top view of SEM is quasi hexagonal?,significantly increasing the density for hot structure spots.2?The optimal coating thickness of 200nm and 360nm diameter polystyrene colloidal spheres are respectively 50nm and 80nm.And the SERS hot spot structure density of 200nm diameter colloidal spheres in unit area is significantly larger than that of 360nm diameter colloidal spheres.For the gold particles roughened structure that prepared by ion sputtering coating on the surface of spherical colloidal,the analysis of its formation mechanism has been made.3?Aiming at the problem of food safety,SERS substrate realized the detection of low concentration of 10^-5mol/L Sudan red III and melamine.At the same time,combined with photo catalytic technology,the SERS substrate catalysis research of methylene blue has been studied.