Reliable Method for Assembling Silver Nanosheets on Different Materials for Effective and Reproducible SERS Substrates

Silver (Ag) nanosheets were successfully coated on the glass slides, filter paper, bottle cap-PP, and bottle body-PET substrates using Ag seed-induced aggregation. The Ag nanoparticles acting as the crystal nucleus were first grown on the supporting substrates, and then citric acid and ascorbic acid were introduced to act as morphology-controlling agents to enable the assembly of silver nanosheets on the supporting substrate. The as-prepared Ag substrates were used as effective surface-enhanced Raman scattering (SERS) substrates for the detection of trace amounts of small molecules. Using Rhodamine 6G (R6G) as probing molecules, it was found that the Raman signal of R6G could be still detected when the concentration of R6G was as low as 10–10 mol/L for the glass slides, filter paper, bottle cap-PP, and bottle body-PET SERS substrates, and the enhancement factor (EF) values of glass slide, filter paper, bottle cap-PP and bottle body-PET substrates were 1.21 × 107, 0.82 × 107, 1.93 × 107 and 2.07 × 107, respectively. In addition, the relative standard deviation (RSD) was also calculated, and the values for the four SERS substrates were 9.7, 21.6, 6.3, and 6.1%, respectively. This method has been proven to be suitable for the growth of Ag nanosheets on different substrates and has broad potential applications in the detection of trace small molecules.