Tunable Molecular Plasmons in Polycyclic Aromatic Hydrocarbons
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- 作者：Alejandro Manjavacas ; Federico Marchesin ; Sukosin Thongrattanasiri ; Peter Koval ; Peter Nordlander ; Daniel S谩nchez-Portal ; F. Javier Garc铆a de Abajo
- 刊名：ACS Nano
- 出版年：2013
- 出版时间：April 23, 2013
- 年：2013
- 卷：7
- 期：4
- 页码：3635-3643
- 全文大小：595K
- 年卷期：v.7,no.4(April 23, 2013)
- ISSN：1936-086X
文摘
We show that chemically synthesized polycyclic aromatic hydrocarbons (PAHs) exhibit molecular plasmon resonances that are remarkably sensitive to the net charge state of the molecule and the atomic structure of the edges. These molecules can be regarded as nanometer-sized forms of graphene, from which they inherit their high electrical tunability. Specifically, the addition or removal of a single electron switches on/off these molecular plasmons. Our first-principles time-dependent density-functional theory (TDDFT) calculations are in good agreement with a simpler tight-binding approach that can be easily extended to much larger systems. These fundamental insights enable the development of novel plasmonic devices based upon chemically available molecules, which, unlike colloidal or lithographic nanostructures, are free from structural imperfections. We further show a strong interaction between plasmons in neighboring molecules, quantified in significant energy shifts and field enhancement, and enabling molecular-based plasmonic designs. Our findings suggest new paradigms for electro-optical modulation and switching, single-electron detection, and sensing using individual molecules.