Uniform and Controllable Preparation of Ag-Au Composite Cascade Hollow Nanoarrays and Applications in SERS Trace Molecules Detection

In recent years, surface-enhanced Raman scattering (SERS) technique based on localized electromagnetic field enhancement on noble metal surfaces has received extensive attention in the field of trace molecule sensing and detection. However, in the process of practical application, the current SERS detection performance is still unable to achieve high detection sensitivity and high repeatability at the same time. In this paper, an efficient and controllable preparation method of Ag-Au composite cascade hollow nanoarray SERS substrates were provided based on nanoimprinting, conformal transfer and electrodeposition techniques. Crystal Violet (CV) was used as the probe molecule, and a low relative standard deviation of 6.65% of SERS intensity was obtained, and the detection concentration could be as low as 10 (-9) M, which can meet the needs of practical applications. The structure has multi-scale cascade characteristics, and significantly broadens the electromagnetic field enhancement characteristics of traditional single-scale configuration nanostructures on the premise of ensuring the uniformity of SERS detection. Such substrates can provide more abundant molecular adsorption sites, which is conducive to improving SERS detection sensitivity and stability. This method is universal, simple and with controllable and repeatable preparation process, which has good application potential in the construction of large-area uniform cascaded nanoarray structure SERS substrates.