Observation of spectral anisotropy of gold nanoparticles.
Metallic nanoparticles synthesized by solution-phase chemistry usually exhibit various polygonal morphologies. The shape is known to have a great impact on a nanoparticle's optical properties, for instance, the surface plasmon resonance frequency. It remains unclear, however, whether the scattering spectrum of nanoparticles is generally anisotropic in the far field as a result. This simple question turns out to be extremely challenging to address because of the particle-to-particle shape inhomogeneity in a bulk sample, and the high sensitivity of surface plasmon resonance to local environments. We report the observation of scattering angle-dependent spectra using a newly developed single-particle tracking spectroscopy (SPS). Furthermore, we show that SPS has provided a way to directly visualize the rotational random walk of individual gold nanoparticles in water for the first time.
Cang
Hu
H
Department of Chemistry, University of California at Berkeley, Berkeley, California 94720, USA.
Montiel
Daniel
D
Xu
C Shan
CS
Yang
Haw
H
D016880:Anisotropy; D003116:Color; D006046:Gold / Q000737:chemistry*; D008027:Light; D053768:Metal Nanoparticles / Q000737:chemistry*; D013057:Spectrum Analysis / Q000379:methods*
D006046:Gold