Regulation of Optical Absorption Characteristics and SERS Performance of Cascaded Nanoparticles

It is extensively utilized in surface-enhanced Raman scattering (SERS) to achieve significant amplification of local electromagnetic fields through plasmon coupling of nanomaterials. The formation of metal nanostructures with varying sizes, resulting in minuscule gaps, will provide a more pronounced cascade amplification effect on the incident light field. In this research, chemical reduction and nanoparticle growth procedures were utilized to generate Au nanoparticles (AuNPs) of varied sizes. A mixed AuNPs (M-AuNPs) substrate with a cascade structure was prepared by the pin-two mixing method. The optimal results show that the relative peak strength of SERS is 30 times higher than that of a single size. By employing Mesna and Hemoglobin (HGB) as the probe molecules for SERS detection, the substrate showed reliable detection sensitivity and reproducibility, even if HGB is denatured. The M-AuNPs substrate with a cascade structure was confirmed to significantly enhance local electromagnetic fields, offering a novel approach for the preparation of high-efficiency SERS substrates.