Synthesis and Plasmonic Property of Ag Nanorods

Abstract

In this paper, Ag nanorods (AgNRs) with different aspect ratios (ARs) were prepared by a seed-mediated fast growth approach. The possible growth mechanism of Ag nanostructures was proposed. With a strong interaction between CTAB and Ag seeds, the reduced Ag atoms agglomerated and attached to the performed Ag nanoparticles, where CTAB molecule layer plays a role of rod-like micelles template, leading to one dimensional growth of Ag atoms into AgNRs. The influences of the reaction conditions were discussed on the yield of AgNRs. The surface plasmon resonance (SPR) of AgNRs was studied by finite-difference time-domain (FDTD) simulations. The simulated results indicate that the transverse surface plasmon resonance (SPRT) has no obvious shifting, whereas the longitudinal surface plasmon resonance (SPRL) shows a significant redshift with the increase of AR of AgNRs, which agrees well with the experimental variation trend. It is also found that the absorption and scattering of AgNRs are stronger than that of Au nanorods (AuNRs), which is in accordance with the Raman signal enhancement by AgNRs compared with that of AuNRs, indicating that AgNR is a promising candidate in bio-molecular detection.