Surface Plasmon Resonances in Silver Nanostars

• DOI: 10.3390/s18113821
• Publication Date: 2018-11-09T08:08:02Z
• Authors: Faustino Reyes Gómez; Rafael J. G. Rubira; Sabrina A. Camacho; Cibely S. Martin; Robson R. Da Silva; Carlos J. L. Cons...; Priscila Alessio; Osvaldo N. Oliveira; J. Ricardo Mejía-...
• Keywords: Chemical technology; Plasmonic biosensing; Ag nanostars; 500; 535; TP1-1185; metallic nanoparticles; 01 natural sciences; Article; 0104 chemical sciences; 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.