Preparation And Study Of New Type Surface Enhanced Raman Scattering Substrate

Surface-enhance Raman scattering,a fingerprint method to characterize the vibrational levels of molecules,has been widely studied for tracing a tiny amount of chemical substances in analytical chemistry,biology and environmental science.SERS has many advantages,such as:rapid detection,high sensitivity,low demand on the sample preparation,strong anti-interference ability..The typical material for SERS is noble metal,such as Au,Ag and Cu and the majority of earlier fabrication techniques relied on the first provision of a hard template such as glass and silicon wafer that makes the traditional substrate has two shortcomings.(1)The substrate is liable to oxidation.(2)The substrate can not fit non-planar surface and provide in situ ultrasensitive SERS analysis.To solve these problems,his article has carried out a series of research works.(1)A novel surface-enhanced Raman scattering(SERS)substrate based on a double-deck structure of monolayer graphene and Ag nanoparticles(AgNPs)layer was proposed.Using adenosine as the probe molecule,shows that the graphene film can significantly improve the signal-to-noise ratio and protect the AgNPs from oxidation.The minimum detected concentration of adenosine can be as low as 10-7M.Moreover,a good linear response between Raman intensity and adenosine concentration was obtained in a range of 10-3 to 10-7M,which shows good potentialities in biomolecule detection.(2)Few layers MoS2 were directly synthesized on Ag nanoparticles(AgNPs)by thermal decomposion method to fabricate a MoS2/AgNPs hybrid system for surface-enhanced Raman scattering(SERS).The MoS2/AgNPs hybrid system shows high performance in terms of sensitivity,signal-to-noise ratio,reproducibility and stability.The minimum detected concentration from MoS2/AgNPs hybrid system for R6 G can reach 10-9 M,which is one order of magnitude lower than that from AgNPs system.The hybrid system shows the reasonable linear response between the Raman intensity and concentration that R2 is reached to 0.988.Besides,the hybrid system has a good stability,the Raman intensity only drop by 20% in a month.(3)A high cost-performance surface-enhanced Raman scattering(SERS)flexible substrate is demonstrated,which endowed with excellent optical transparency,high SERS activity and largescale.This SERS flexible substrate of Ag/Cu/Polyethylene Terephthalate(PET)was prepared by replacing Cu atoms with Ag atoms in situ on Cu nano-film.The Ag/Cu/PET flexible substrate shows high sensitivity in SERS detection and the minimum detected concentration of R6 G can reach 1010 M.In addition,the residual methylene blue(MB)on a fish surface was selected as the analyte,the results no doubt shows the potential of SERS technology application in food detection...