Seed-mediated growth of flexible Ag NFs with high activity and their application for SERS detection of thiram in tomato juice

In this study, a prospective strategy on seed-mediated growth in vacuum is provided and used to prepare flexible silver nanofilms (AC 0–3 NFs) with high purity, crystallinity and SERS performance. Noteworthy, AC 2 NFs surface is uniformly covered with silver nanoparticles (Ag NPs), following the appearance of numerous nano-gaps between Ag NPs. Through the finite-difference time-domain (FDTD) simulation, it is found that the ultra-small nano-gaps less than 5 nm can generate abundant “hot spots” to amplify the Raman signal. Therefore, the above AC 2 NFs as SERS substrates exhibit superior activity for the SERS detection of thiram in tomato juice, with the limit of detection (LOD) of 10 −15 M and the enhancement factor (EF) of 3.7 × 10 11 . Meanwhile, AC 2 NFs show outstanding reproducibility and stability during the SERS detection. Additionally, the calibration curve is established, by which the thiram (10 −7 to 10 −15 M) can be quantitatively detected. Clearly, the as-prepared flexible AC 2 NFs have great potential in the SERS detection and analysis.