We focus on the possibility to study the optical properties of single metal particles using dark-field microscopy. It is now possible to routinely collect the scattered light from single metal nanocrystals and use this to study the effects of particle size and shape on the surface plasmon (SP) resonances. We show that the linewidth and energy of the SP resonance is acutely sensitive to the particle end cap geometry, to the aspect ratio and to atomic roughness on the particle surface. We map the surface plasmon resonance landscape for six different crystal morphologies of gold nanocrystals.

References:

1. “Gold Nanorods: Synthesis, Characterization and Applications”, J.Pérez-Juste, I. Pastoriza-Santos, L.M. Liz-Marzán, P. Mulvaney, Coord. Chem. Rev. 249, 1870-1901 (2005).

2. “On the temperature stability of gold nanorods: comparison between thermal and ultrafast laser-induced heating”, Hristina Petrova, Jorge Perez Juste, Isabel Pastoriza-Santos, Gregory V. Hartland, Luis M. Liz-Marzán and Paul Mulvaney, PCCP, 8,814-821 (2006).

3. “Drastic Surface Plasmon Mode Shifts in Gold Nanorods due to Electron Charging”, Paul Mulvaney,Jorge Pérez-Juste, Michael Giersig, Luis M. Liz-Marzán, Carlos Pecharromán, Plasmonics, 1, 61-66 (2006).

4. “Gold nanorod extinction spectra”,S.Prescott,P.Mulvaney,J. Appl. Phys. 99,123504 (2006).

5. “Redshift of surface plasmon modes of small gold rods due to their atomic roughness and end-cap geometry”, Carlos Pecharromán, Jorge Pérez-Juste, Gustavo Mata-Osoro, Luis M. Liz-Marzán, and Paul Mulvaney Phys. Rev. B 77, 035418 (1-7) (2008).

6. “Influence of the Medium Refractive Index on the Optical Properties of Single Gold Triangular Prisms on a Substrate”, Carolina Novo, Alison M. Funston, Isabel Pastoriza-Santos, Luis M. Liz-Marzán, Paul Mulvaney, J.Phys Chem C 112, 3-7 (2008).

7. “Contributions from radiation damping and surface scattering to the linewidth of the longitudinal plasmon band of gold nanorods: a single particle study” Novo C, Gomez D, Perez-Juste J, et al. Hartland, G.V.; Mulvaney, P.; PCCP 8, 3540-3546 (2006).

8. "Routine Spectroscopy and High Resolution Microscopy of the Same Individual Nanocrystal using a Focussed Ion Beam Registration Method", Carolina Novo, Alison M. Funston, Isabel Pastoriza-Santos, Luis M. Liz-Marzán, and Paul Mulvaney, Angew. Chem. 46, 3517-21 (2007).

9. “Charge Induced Rayleigh Instabilities in Small Gold Rods” Carolina Novo & Paul Mulvaney, Nanoletters 7, 520-524 (2007).