Surface Plasmon Resonances in Silver Nanostars

• Main Author: Reyes Gómez, Faustino
• Publication Date: 2018
• Other Authors: Rubira, Rafael J G [UNESP], Camacho, Sabrina A. [UNESP], Martin, Cibely S. [UNESP], da Silva, Robson R., Constantino, Carlos J L [UNESP], Alessio, Priscila [UNESP], Oliveira, Osvaldo N., Mejía-Salazar, J Ricardo
• Format: Article
• Language: eng
• Source: Repositório Institucional da UNESP
• Download full: http://dx.doi.org/10.3390/s18113821; http://hdl.handle.net/11449/188343
• topic: Ag nanostars; metallic nanoparticles; plasmonic biosensing

The recent development of silver nanostars (Ag-NSs) is promising for improved surface-enhanced sensing and spectroscopy, which may be further exploited if the mechanisms behind the excitation of localized surface plasmon resonances (LSPRs) are identified. Here, we show that LSPRs in Ag-NSs can be obtained with finite-difference time-domain (FDTD) calculations by considering the nanostars as combination of crossed nanorods (Ag-NRs). In particular, we demonstrate that an apparent tail at large wavelengths ( λ ≳ 700 nm) observed in the extinction spectra of Ag-NSs is due to a strong dipolar plasmon resonance, with no need to invoke heterogeneity (different number of arms) effects as is normally done in the literature. Our description also indicates a way to tune the strongest LSPR at desired wavelengths, which is useful for sensing applications.