Application And Construction Of Silver-Based Composite Sers Substrates Based On "Hot Spot" Effect

Surface-enhanced Raman scattering（SERS）has been rapidly paid more and more attentions and applied in medical diagnosis,environmental monitoring,food and medicines supervision and many other fields due to its high sensitivity,specificity,mild reaction conditions and rich fingerprint information.In order to meet the growing demand for highly sensitive analysis and detection,designing and constructing functional SERS substrates with high-density hotspots has gradually become key and research focus in this field.Three types of Ag-based composite SERS substrates based on different carriers have been constructed to achieve rapid and highly sensitive detection of target molecules,and expected to provide new options for practical application.（1）Acanthosphere CuO structure was firstly synthesized by hydrothermal synthesis method,then,AgNPs were assembled on the surface of CuO by in-situ redox method to obtain like-acanthosphere CuO/AgNPs nano-composite structure.With adjustment of the temperature of the hydrothermal reaction,the performance of the prepared SERS active substrate was optimized.As the SERS substrate,the results show a higher sensitivity,lower detection limit and have high uniformity and reproducibility for CV.In addition,the substrate showed high sensitivity(LOD=10^-8 M)for illegal additive Sudan III in chili powder.The results indicated that the prepared SERS substrates had great potential in food inspection,environment protection,and some other application fields.（2）Under acidic conditions,APS is used as an oxidizing agent to prepare conductive polymer PANI.And then the AgNPs are decorated on the surface of PANI by redoxreaction.With adjustment of the concentration of the Silver nitrate solution,the performance of the prepared SERS active substrate was optimized.As the SERS substrate,the results show a good SERS enhancement effect and have high uniformity and reproducibility for CV.In the actual application,the detection of Sudan III was preliminary explored,and the detection limit could reach 10^-8 M.（3）The needle-like Si nanowires jungle structure was constructed by PECVD method.And then the silver nanoparticles（AgNPs）are decorated on the surface of Si nanoneedles by galvanic displacement.The as-prepared micro-nanostructure SERS substrates（AgNPs decorated needle-like Si nanowires）showed an outstanding SERS enhancement effect and low detection limit for Sudan I、Sudan II.This work explores the growth mechanism of needle-like Si nanowires and provides new ideas for the preparation of various semiconductor nanowires and needle-like nanowires SERS substrates.