V. Amendola, O.M. Bakr and F. Stellacci
Plasmonics, 5(1), pp. 85-97, (2010)
The surface plasmon resonance (SPR) of silver nanoparticles (AgNPs) was
studied with the discrete dipole approximation considering different
shapes, sizes, dielectric environments, and supraparticles assemblies.
In particular, we focused our simulations on AgNPs with sizes below
10 nm, where the correction of silver dielectric constant for intrinsic
size effects is necessary. We found that AgNPs shape and assembly can
induce distinctive features in the extinction spectra and that SPR is
more intense when AgNPs have discoid or flat shapes and are embedded in a
dielectric shell with high refractive index. However, the SPR loses
much of its distinctive features when size effects and stabilizing
molecules induce significant broadening of the extinction bands that is
often observed in the case of thiolated AgNPs smaller than about 5 nm.
These results are useful indications for in situ characterization and
monitoring of AgNPs synthesis and for the engineering of AgNPs with new