Layer-by-layer assembly of silver nanoparticles on diatom frustules for surface-enhanced Raman scattering

Abstract

Surface-enhanced Raman Scattering (SERS) is an emerging analytical technique used for characterization of biological and non-biological structures. Plasmonic properties of nanostructures are main factors influencing SERS performance. Thus, fabrication of plasmonic nanostructures having different plasmonic properties is a significant research interest. Recently, guided-mode resonances (GMRs) in diatoms have significant attention due to their potential contribution to SERS enhancement. Furthermore, there is also evidence showing that diatoms can be utilized in improving SERS enhancement by optically coupling the GMRs of the diatom frustules with the LSPRs of the nanostructures. In this study, inexpensive, robust, and flexible diatom-based SERS platforms having different number of layers on a box tape are fabricated using layer-by-layer assembly of silver nanoparticles (AgNPs). The fabricated SERS platforms are characterized using UV-Vis spectroscopy and scanning electron microscopy (SEM). The SERS performance of the platforms was evaluated using 4 aminothiophenol (4-ATP) and rhodamine-6G. The results demonstrate that SERS performance of the platforms is dependent on the number of layers of the structures. The SERS platform having highest SERS activity can be used for the characterization of any molecules of interest