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Presenter: Yao Cui - Nordlander Nanophotonics group, Rice University, Houston, Texas
Supervisor: SPIE Student Chapter, University of Victoria

Date: Mon, June 8, 2015
Time: 13:30:00 - 00:00:00
Place: ECS 660

ABSTRACT

Abstract:

We report the experimental observation of plasmon resonances in polycyclic aromatic molecules (PAHs) with the addition of a single electron to the neutral molecule. We observe that the charged PAHs support intense absorption in the visible regime with geometrical tunability analogous to plasmonic resonances of much larger nanoscale systems. These observations confirm earlier predictions that picoscale-confinement of graphene structures, containing only a few dozen atoms, should possess a plasmon resonance fully switched on by the addition or removal of a single electron. Graphene supports surface plasmons in the mid- to far-infrared that are both electrically and spatially tunable. Reduced-dimensional graphene structures including nanoribbions and nanodisks exhibit higher frequency plasmons throughout the mid- and near-infrared regimes due to additional electronic confinement of the electrons to smaller length scales. In contrast to larger graphene nanostructures, the PAH absorption spectra possess a rich and complex fine structure that we attribute to the coupling between the molecular plasmon and the vibrational modes of the molecules. The vibrationally-resolved absorption spectra were calculated following the procedure developed by Bloino et al., which relies on the Franck-Condon principle to obtain the strength of the transitions between the vibrational levels of the ground state and the excited electronic states obtained by time-dependent density functional theory (TDDFT).

Biography:

Yao Cui is currently a graduate student in Peter Nordlanders Nanophotonic group at Rice University. She has a broad background in Computational Science specializing in Chemistry and Photonics. Prior to attending Rice she completed her bachelor's degree in Materials chemistry in Nankai University in China. Currently she is focusing on Molecular plasmons as it relates to polycyclic aromatic molecules. Yao Cui is also the president of Rice's SPIE student chapter.

Sent on behalf of Levi Smith - levismit@uvic.ca