Fabrication Of Cuag/Cicada Wing Composite Substrate And Study Of SERS Performance

Surface enhanced Raman scattering(SERS),as the “fingerprint”of molecules,has become one of the powerful and universal analytical tools in the fields of biosensor,analytical chemistry,food safety,etc.due to its advantages of rapid response,non-destructive analysis and ultra-sensitive detection.Compared with single metal nanostructures,SERS substrates with bimetallic core-shell structure have attracted more and more attention due to the enhancement of Raman signal of metal surface molecular probes,and the adjustment of surface plasmon resonance characteristics by adjusting the size of core-shell metal.Based on this,in this paper,bimetallic materials were constructed on the surface of natural cicada wings with large-scale nano-column array to obtain bimetallic@cicada wings SERS substrates with different core-shell,and their optical properties were systematically studied.The specific research contents are as follows:Firstly,the SERS properties of copper films were studied by modifying the regular array structure.Using cicada wing as substrate,copper nanoparticles were modified on the regular array structure by simple and fast magnetron sputtering technology.The growth of particles on the surface was observed by scanning electron microscope,and the sputtering time was used to optimize the structure of Cu@CW substrate.At the same time,rhodamine6 G and p-aminothiophenol were used as probe molecules to test the enhancement and SERS performance.Secondly,the dispersion and aggregation of silver nanoparticles on silver films and their optical properties were studied.A layer of silver film was sputtered on the surface of cicada wings by magnetron sputtering.The SERS enhancement performance of silver film was optimized by adjusting the sputtering time of silver film combined with Raman spectrometer.After that,silver nanoparticles with an average diameter of 30 nm were attached to the surface of silver film by oil-water separation method.The dispersion and aggregation of AgNPs@Ag@CW substrate and its optical properties were observed by scanning electron microscope and Raman spectroscopy.Finishly,the core-shell structure of Cu Ag thin films and their SERS properties were studied.Copper and silver films were sputtered successively on the surface of cicada wings.SERS substrates with different plasmon resonance characteristics were obtained by adjusting the film thickness of copper core and silver shell.With the help of scanning electron microscope and Raman spectrometer,the growth of core-shell substrate and the intensity of Raman signal were analyzed,and the best SERS enhanced substrate was obtained.At the same time,the SERS performance and local field distribution of the substrate were characterized by experimental spectrum and three-dimensional finite-difference time-domain simulation.