Preparation Of Two-dimensional SERS Substrates With Different Configurations And Detection Study

The surface enhanced Raman scattering?SERS?can make the molecules signal enhanced on rough metal surface near 104¹06 times.Itmakes up for the shortcomings of low sensitivity of Raman spectroscopy.The application of SERS depends on the SERS substrate,so this thesis focuses on the preparation and application of the SERS substrate:We make up the SERS substrate based on the spherical Ag nanoparticles self-assembly membrane.We grow a layer of silver shell on the surface ofSiO₂@Au nanoparticles rapidly.Thegap between the nanoparticles of the self-assembly membranecan format the hotspot.Especially the incident light reflect in the wall among SiO₂@Au@Ag nanoparticles.They both make the signal of probe molecules greatly enhanced.4-mercaptopyridine is used as probe molecules,the detection limit can reach 10-11 M,the Raman enhancement factor is 2.57 ×107.However,For the spherical self-assembly nanoparticles,the detection limit is 10-8M.The result shows the spherical Ag nanoparticles self-assembly membrane has absolutely advantage compared with the spherical structure.Meanwhile we can use it to detect pesticide residues on the surface of apple.We only need to use this self-assembly substrate to rub against the apple surface gently before SERS detection.This method is simple and easy to operate.Environmental pollution is a worldwide growing concern and it is imperative to detect natural and anthropogenic toxic contaminants,especially organic species that pose serious health effects.We make the sandwich structure consists of graphene oxide/molecular imprinting polymers?GO/MIPs?,target molecules,and surface-enhanced Raman scattering?SERS?active sliver nanoparticles?Ag NPs?.We combine the advantages of molecular imprinting technique and surface enhanced Raman technology to realize the ultra-sensitive detection of organic compounds.In this structure,GO provides good binding sites for MIPs.This sandwich structure has good SERS performance and anti-interference and selective adsorption to template molecule,the SERS detection limit is 10-11 M.When the template and other analogues were mixed,the sandwich structure can selective adsorb the template molecule and its anti-interference property is good,This method can be easily extended to other small molecules,which shows great promise in the ultrasensitive detection of a wide variety of organic pollutions.