Design and Fabrication of Ag Nanoparticles and Plasma Hybrid Polymer Thin Films for the New LSPR Sensor Application

ABSTRACT Enabling detection of target molecules at low concentration is a key feature in localized surface plasmon resonance (LSPR) biosensors, which utilizes the remarkable optical properties of gold based metal nanoparticles (NPs). For a schematic studies, we here propose and demonstrate an approach on a low‐cost Ag‐based LSPR platform that combines a nanostructured Ag layer formed from spin‐coated Ag ink and a plasma‐polymer dielectric overlayer (Me‐cyclohexane or Me‐cyclohexane+TEOS) deposited by plasma‐enhanced chemical vapor deposition (PECVD) on glass (or flexible polymer) substrates with different thickness layer and particle size. Rather than assuming ideal, monodisperse nanoparticles, the Ag layer is treated as an island/clustered nanostructure whose thickness (32 vs 50 nm) and surface roughness govern the optical response. Using p‐polarized readout, we observe a steeper concentration‐dependent intensity change for the 50 nm Ag nanostructure compared with the 32 nm sample when probing aqueous thioglycolic acid (TGA) and representative organic dyes. In addition, a theoretical calculation utilizing our experimental data carry out for making up some weakpoint especially on refractive index sensitivity (RIS) and figure of merit.