A Multilayer Interlaced Ag Nanosheet Film Prepared by an Electrodeposition Method on a PPy@PEDOT:PSS Film: A Strategy to Prepare Sensitive Surface-Enhanced Raman Scattering Substrates

A highly sensitive multilayer interlaced silver (Ag) nanosheet (MISN) film was prepared on a PPy@PEDOT:PSS film via an electrodeposition method for surface-enhanced Raman scattering (SERS) applications. After the PPy@PEDOT:PSS film was pretreated with ascorbic acid solution, many sparse Ag nanoparticles (NPs) could be directly reduced on the surface of the PPy@PEDOT:PSS film in AgNO3 solution. Then, the MISN film was directionally grown along the surface of sparse Ag NPs by using an electrochemical galvanostatic method to form a Ag/PPy@PEDOT:PSS film for a SERS substrate. The results indicated that with the increase in electrodeposition time, the density of Ag nanosheets was also increased for boosting the SERS effect. Accordingly, owing to the directional growth of Ag NPs, the increase in the length–width ratio of single Ag nanosheets would further promote the SERS signal of the substrate. Moreover, the maximum enhancement factor of the SERS substrate could reach to 12,478, and the minimum limit of detection of melamine solution was down to 5.42 ng/mL. The SERS sensitivity of the Ag nanosheet film reached 100.65. This method of preparing the SERS substrate provides a novel and robust strategy for the low-cost and high-sensitivity detection in biomedicine, drugs, and food.