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Two‐photon photoluminescence and exciton binding energies in single‐walled carbon nanotubes
Author(s) -
Pomraenke R.,
Maultzsch J.,
Reich S.,
Chang E.,
Prezzi D.,
Ruini A.,
Molinari E.,
Strano M. S.,
Thomsen C.,
Lienau C.
Publication year - 2006
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200668080
Subject(s) - exciton , carbon nanotube , rydberg formula , photoluminescence , binding energy , photoluminescence excitation , spectral line , ab initio , atomic physics , molecular physics , luminescence , excitation , ab initio quantum chemistry methods , materials science , chemistry , physics , condensed matter physics , nanotechnology , quantum mechanics , optoelectronics , ionization , ion , organic chemistry , molecule
We compare experimental one‐ and two‐photon luminescence excitation spectra of single‐walled carbon nanotubes at room temperature to ab initio calculations. The experimental spectra reveal a Rydberg‐like series of excitonic states. The energy splitting between these states is a clear fingerprint of excitonic correlations in carbon nanotubes. From those spectra, we derive exciton binding energies of 0.3–0.4 eV for nanotubes with diameters between 6.8 Å and 9.0 Å. These energies are in quantitative agreement with our theoretical calculations, which predict the symmetries of the relevant excitonic wave functions and indicate that a low‐lying optically dark excitonic state may be responsible for the low luminescence quantum yields in nanotubes. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)