| Since the surface-enhanced Raman scattering(SERS)active substrate has an extremely high stability and high sensitivity,it has been eagerly concerned by many researchers at home and abroad since it was first discovered in 1974.Researchers' research on the application of SERS is mainly concentrated in the fields of biology,environment and chemistry.A large number of experimental results show that SERS is an easy-to-operate and non-destructive analysis method for detection objects,which circumvents the main shortcomings of ordinary Raman scattering detection,such as susceptibility to interference and weak signal.SERS is generally able to increase the weak Raman scattering signal inherent in the detection object by hundreds of millions.At present,the SERS substrate,especially the "suspended SERS active substrate",has been studied for a long time,and there have been a large number of research results in its theory and practice,and their application has also been greatly developed.Therefore,it is of great significance for the further development and application of SERS to prepare the "solid SERS active substrates" which are stable,reproducible,highly sensitive and can be prepared by a simple preparation method.This thesis systematically studies the preparation mechanism,preparation method,and nanomorphology of porous silicon composite silver nanoparticles / dendritic structures from both theoretical and experimental aspects,and reveals the microstructure of composite structures with different concentrations of silver nitrate solution in the electrolyte.The effects of surface appearance and composition distribution on SERS performance were studied comprehensively and systematically.This thesis will systematically elaborate on the main research content and innovations of the subject from the following three aspects:First,a porous silicon-silver nanoparticle / dendritic composite substrate was prepared based on the electrochemical anodic corrosion oxidation method commonly used to prepare porous silicon.By exploring the effects of different corrosion conditions(different concentrations,different currents,different voltage,etc.)on the fabrication of composite structures,a one-step rapid preparation method of porous silicon-silver nanoparticle / dendritic composite structure was proposed.Secondly,the SERS properties of the porous silicon-silver nanoparticle / dendritic composite structure were studied and it was proved that the structure has high SERS activity.The specific effect of the different concentrations of the silver nitrate solution in the electrolyte on the surface morphology of the SERS active substrate was investigated,and the microscopic surface morphology of the sample was observed and analyzed to obtain the optimal value of the experimental variable silver nitrate solution concentration.To study the high SERS active substrate prepared in this thesis further,the effect of the concentration of the silver nitrate solution on the SERS performance of porous silicon-silver nanoparticle / dendritic substrate is further explored,and the optimal concentration value of silver nitrate solution is obtained with SERS performance as a reference and the component mass ratio of each SERS substrate are analysed in detail by X-ray diffraction.Finally,based on the porous silicon-silver nanoparticle / dendritic composite structure designed and prepared in this thesis,the application research was carried out,and the SERS detection of rhodamine 6G was achieved.In addition,this thesis also further explores the stability,reproducibility,and sensitivity of the SERS active substrate.This thesis proposes a one-step preparation method of porous silicon-silver nanoparticle / dendritic composite structure based on electrochemical corrosion to rapidly prepare a porous silicon-silver nanoparticle/dendritic composite structure with high SERS properties,and this kind of substrates have huge potential applications in biological detection and environmental monitoring. |
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