Controllable Synthesis Of Ag-au Nanocomposites Mimicking Micro-nano Structure Of Butterfly Wings And Research Of SERS Property

Surface enhanced Raman scattering（SERS）has been widely used in the field of material science,surface analysis,biomedicine and other fields as a high-sensitivity and rapid analysis tool.SERS substrate is the key factor of affecting SERS detection technology.In order to improve its sensitivity and repeatability,more economical and efficient preparation methods are of great significance.The sensitivity of SERS substrate depends on the surface plasmon resonance characteristics,whose main factors include the composition,size,morphology,structure and so on.Therefore,this study was carried out in three aspects:component optimization,structural optimization and morphology optimization.The nano Ag-Au was selected while the forewing of euploea mulciber with fine micro-nano structure was introduced as biological template to develop a simple and convenient SERS substrate preparation method.The main results are as follows:Firstly,choosing the forewing of euploea mulciber as a biological template,controlling the 30-50nm Ag-Au nanoparticles,50-80nm hollow Ag-Au nanospheres and irregular nano Ag-Au particles uniform,loaded on the butterfly’s wing to obtain the finely graded nanometer Ag-Au/wing composite material by means of step-by-step chemical reduction method.Analyzing the function of the butterfly’s wing template and the formation mechanism of gold,silver and nano-particles were made with different shapes,which provided an important reference to prepare fine structure and multi-component functionalities nanocomposites effectively.Secondly,the micro-nano structure Au-Ag/wing and Au-Ag-Au/wing composite material were prepared by chemical deposition method by optimizing the impregnation solution concentration,impregnation time and other process parameters.After the process optimization,the surface of the wing was uniformly covered by the 40-50nm gold-silver composite particles,achieving the perfect replication of the wing’s fine micro-nano structure.Thirdly,the SERS properties of the fine nano structure of Au-Ag/wing and Au-Ag-Au/wing composite were detected with R6G as signal molecules.Study the relationship with structure and composition of Au-Ag-Au/wing samples and the SERS properties.The results showed that Au-Ag/wing and Au-Ag-Au/wing composites with fine micro Ag-Au/wing composite materials can detect 10^-9mol/L R6G signaling molecules.The results could provide a reference for the development of simple and efficient preparation of SERS substrate with high sensitivity and reproducibility.