Optimizing gold nanorods dimer structure for sensing platform

The performance of gold nanorod (AuNR) dimer linked end-to-end by thin dielectric junction, as a sensor platform has been investigated. Three-dimensional finite element simulations (COMSOL Multiphysics) in frequency domain were carried out to study the influence of local environment on the optical features of AuNR dimer, with different junction lengths and aspect ratios. This computational approach focused on understanding the LSPR spectral peak position and spatial distribution of electromagnetic field enhancement near the surface of individual gold nanorod dimer, in order to reveal the behavior of crucial parameters such as figure of merit and bulk sensitivity, which predicts the LSPR sensor performance. We find the plasmon peak position of end-to-end connected Au nanorod dimer exhibited red shift by at least 60 nm from single Au nanorod. The simulations reveal that silica linked dimer of gold nanorod sensing platform shows higher sensitivity (717 nm/RIU) as compared to individual gold nanorod. We observed that silica bridge dimer also exhibit a high figure of merit value, up to 16.9. Our proposed model put forth a new paradigm in LSPR based sensing applications.