Abstract: The optical excitations of elongated graphene nanoflakes of finite length are investigated theoretically through quantum chemistry semiempirical approaches. The spectra and the resulting dipole fields are analyzed, accounting in full atomistic details for quantum confinement effects, which are crucial in the nanoscale regime. We find that the optical spectra of these nanostructures are dominated at low energy by excitations with strong intensity, comprised of characteristic coherent combinations of a few single-particle transitions with comparable weight. They give rise to stationary collective oscillations of the photoexcited carrier density extending throughout the flake and to a strong dipole and field enhancement. This behavior is robust with respect to width and length variations, thus ensuring tunability in a large frequency range. The implications for nanoantennas and other nanoplasmonic applications are discussed for realistic geometries.

Optical Excitations and Field Enhancement in Short Graphene Nanoribbons / COCCHI, CATERINA; PREZZI, Deborah; RUINI, Alice; BENASSI, Enrico; Marilia J., Caldas; Stefano, Corni; MOLINARI, Elisa. - In: THE JOURNAL OF PHYSICAL CHEMISTRY LETTERS. - ISSN 1948-7185. - ELETTRONICO. - 3:(2012), pp. 924-929. [10.1021/jz300164p]

Optical Excitations and Field Enhancement in Short Graphene Nanoribbons

COCCHI, CATERINA;PREZZI, Deborah;RUINI, Alice;BENASSI, Enrico;MOLINARI, Elisa
2012

Abstract

Abstract: The optical excitations of elongated graphene nanoflakes of finite length are investigated theoretically through quantum chemistry semiempirical approaches. The spectra and the resulting dipole fields are analyzed, accounting in full atomistic details for quantum confinement effects, which are crucial in the nanoscale regime. We find that the optical spectra of these nanostructures are dominated at low energy by excitations with strong intensity, comprised of characteristic coherent combinations of a few single-particle transitions with comparable weight. They give rise to stationary collective oscillations of the photoexcited carrier density extending throughout the flake and to a strong dipole and field enhancement. This behavior is robust with respect to width and length variations, thus ensuring tunability in a large frequency range. The implications for nanoantennas and other nanoplasmonic applications are discussed for realistic geometries.
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Optical Excitations and Field Enhancement in Short Graphene Nanoribbons / COCCHI, CATERINA; PREZZI, Deborah; RUINI, Alice; BENASSI, Enrico; Marilia J., Caldas; Stefano, Corni; MOLINARI, Elisa. - In: THE JOURNAL OF PHYSICAL CHEMISTRY LETTERS. - ISSN 1948-7185. - ELETTRONICO. - 3:(2012), pp. 924-929. [10.1021/jz300164p]
Cocchi, Caterina; Prezzi, Deborah; Ruini, Alice; Benassi, Enrico; Marilia J., Caldas; Stefano, Corni; Molinari, Elisa
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11380/737861
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