Refractive Index Sensitivity (RIS) and Thermoplasmonic Response of Au-/Ag-Decorated Alloy Nanoshells

The present study is centered around investigating the thermo-optical features and the performance concerning the inflection points (IFs) in hybrid composite nanostructures, focusing on Au- and Ag-decorated alloy configurations, and their response in diverse refractive index (RI) conditions (n = 1.30 to 1.55). Au-decorated alloys demonstrate intriguing localized plasmonic resonance (LSPR) exhibiting LSPR shifts in response to various RI’s, indicating improved response with notable red and blue shifts ( \({\lambda }_{max}=\) ${\lambda }_{\mathit{max}}=$ 502–564 nm) indicating effective absorption efficiency. In contrast, Ag-decorated alloys exhibit enhanced absorption efficiency at higher RI’s, presenting minimal LPSR shifts ( \({\lambda }_{max}=\) ${\lambda }_{\mathit{max}}=$ 398–449 nm) among various RI’s. In the context of thermoplasmonics, the surface temperature of Au/Ag-decorated nanocomposites exhibits ranges of 2.39 to 3.03 \(^\circ{\rm C}\) ${}^{\circ }\mathrm{C}$ , and 2.09 to 3.55 \(^\circ{\rm C}\) ${}^{\circ }\mathrm{C}$ for specific optical flux, respectively. Furthermore, an improvement in RI sensitivity is achieved, ranging from 144 to 308 nm/RIU for Au-decorated and 164 to 180 nm/RIU for Ag-decorated alloy nanocomposites. Detailed scrutiny of Au and Ag-layered alloy nanostructures suggests new opportunities towards ultra-sensitive biosensors and precise biomedical uses.