<p>Quasi-fractal gold nanoparticles can be synthesized via a modified
and temperature controlled procedure initially used for the synthesis of star-like
gold nanoparticles. The surface features of nanoparticles leads to improved
enhancement of Raman scattering intensity of analyte molecules due to the
increased number of sharp surface features possessing numerous localized
surface plasmon resonances (LSPR). The LSPR is affected by the size and shape
of surface features as well as inter-nanoparticle interactions, as these affect
the oscillation modes of electrons on the nanoparticle surfaces. The effect of
the particle morphologies on the LSPR and further on the surface-enhancing
capabilities of these nanoparticles is explored by comparing different
nanoparticle morphologies and concentrations. We show that in a fixed nanoparticle
concentration regime, Quasi-fractal gold nanoparticles provide the highest
level of surface enhancement, whereas spherical nanoparticles provide the
largest enhancement in a fixed gold concentration regime. The presence of
highly branched features enables these nanoparticles to couple with a laser
wavelength despite having no strong absorption band and hence no single surface
plasmon resonance. This cumulative LSPR may allow these nanoparticle to be used
in a variety of applications where laser wavelength flexibility is beneficial,
such as in medical imaging applications where fluorescence at short laser
wavelengths may be coupled with non-fluorescing long laser wavelengths for
molecular sensing. </p>
Assembly-induced microwave band resonance in gold nanoparticles-based ultrathin and flexible spoof localized surface Plasmon
