Construction And Performance Of Layered SERS Substrates

In recent years,micro/nanostructured noble metal substrates have become the research hotspot in the field of surface enhanced Raman scattering(SERS),and graphite oxide(GO),as a new nanomaterial,has great research significance for SERS.In this study,we proposed the idea of layered construction,designed and prepared three new multi-layer SERS substrates,studied the SERS performance and enhancement mechanism of the substrates,and applied them to the detection of environmental organic pollutants.The following are the innovations and contents of this thesis:1.To fully utilize the advantages of noble metal micro/nanostructures and GO,we designed and constructed the Au spherical shell@GO@Au particle sandwich structure array.The array structure can be regulated through multiple parameters.This substrate exhibits excellent SERS performance and potential for detecting environmental organic pollutants,as it combines multiple advantages:significant chemical enhancement of GO;effective capture of GO toward detection molecules;GO reducing the fluorescence background;large physical enhancement of Au(sufficient coupling between spherical shells and particles);template induced structural consistency.In addition,the process is simple,green,and capable of macro preparation,which is expected to be used for practical environmental detection.2.Based on the idea of constructing substrates by assembly of polystyrene colloidal spheres of different sizes,new technologies were developed.Micro/nanostructured array templates were synthesized with the upper layer composed of small spheres,the lower layer of large spheres,and the small spheres uniformly distributed on the surface of the large spheres.After sputtering of Au on the templates and removal of Au,a double-layer Au spherical shell array inheriting the template morphology is obtained.The array structure can be tuned by the process parameters.SERS testing shows that due to its large number of nanogaps(hotspots)and periodicity,the substrate exhibits significant enhancement ability and good signal uniformity.3.In order to deeply explore the role of GO on noble metal micro/nanostructure substrates,basing on the first work,we modified GO on the surface of the double-layer Au spherical shell array and obtained a double-layer Au spherical shell@GO composite substrate.The results indicate that GO further increases the enhancement ability of the substrate and also improves signal uniformity to a certain extent.