Plasmon Tunability and Field Enhancement of Gold Nanostar

Abstract

In terms of LSPR and field enhancement, a comparison of gold nanostar and nanosphere has been done. Thanks to developments in theoretical methodologies for understanding plasmonic behavior in nanoscale metallic structures and dependable nanofabrication procedures, complex metal nanostructures can now be exploited for a range of applications. Star-shaped particles have piqued interest due to their plasmonic properties, which enable a greater number of enhanced field locations than simpler forms. The localized surface plasmon resonance (LSPR) and field enhancement of Gold nanosphere and nanostar were evaluated. The electromagnetic simulations in this study were carried out using FDTD solutions, a product of Lumerical solutions Inc., Vancouver, Canada. Quantitative research was done on the effect of particle size and spike number on peak wavelength. By altering the particle size and amount of spikes, we were able to detect a hot zone around nanostar. For Au nanostar, the peak wavelength for nanostar varies from visible to near-infrared. When compared to a nanosphere of the same dimension, the shift seen in nanostar is substantially higher, making it more suitable for biosensing applications. When the refractive index of the surrounding medium is increased, a red shift in peak wavelength is noticed, forming the basis for a plasmonic refractive index sensor. Aside from having a higher sensitivity, nanostar has a twofold hot spot system due to its unique surfaces. There is no evidence of spike aggregation in the near-field pattern. As a result, it is thought to be a better nanostructure for biosensing applications. The LSPR and field enhancement for Au nanosphere and Nanostar were investigated using the FDTD method. The nanosphere's peak wavelength is in visible region, whereas the nanostar's range extends from visible to near-infrared, depending on the size and number of spikes. At 517 nm, the enhancement factor for a nanosphere was 102, but at 1282 nm, the enhancement factor for a nanostar with six spikes was 108. NA