Toward Plasmon-Controlled Generation of the Activating Ag Hotspot Nanospheres for Quantitative SERS Analysis

Abstract

Introduction: Surface-enhanced Raman scattering (SERS) has attracted enormous concern as a robust vibrational spectroscopy technique with widespread applications, primarily for the ultrasensitive detection of low-concentration molecules and selective identification. Nevertheless, the optimization of SERS efficiency has been impeded by limitations in controlling the size of nanoparticles utilized in this technique. Method: In this study, the morphology, structure, chemical components, and optical properties of the as-synthesized Ag nanoparticles (Ag NPs) via a hydrothermal method were thoroughly investigated by sophisticated analyses. The synthesized Ag NPs were characterized for its morphological characteristics using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-Vis absorption spectroscopy, Raman spectroscopy, and assessed for their SERS performance in detecting organic substances including Crystal Violet (CV) and Rhodamine B (RhB). Results: The results showed that Ag NPs with different sizes could be obtained from 10 to 30 nm. These sizes corresponded to the duration of the hydrothermal method, which was 15, 20, and 25 hours, respectively. The optimal sample exhibited the capability to detect dye molecule solutions at diluted-low concentrations as low as 10-8 M. Conclusion: Through these results, we contribute to advancing the understanding of tailored nanoparticle synthesis for superior SERS performance, thus opening avenues for enhanced molecular detection in various applied analytical fields.