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Excited state properties of neutral and charged ter‐fluorene with and without a keto‐defect
Author(s) -
Beenken W. J. D.,
Sun M.,
Zhao G.,
Pullerits T.
Publication year - 2008
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.200743442
Subject(s) - excited state , fluorene , atomic physics , exciton , ground state , ion , density functional theory , electron , chemistry , molecular physics , physics , computational chemistry , condensed matter physics , polymer , quantum mechanics , organic chemistry
Stimulated by the recent experimental report of optical properties of charged oligofluorenes [S. Fratiloiu et al., J. Phys. Chem. B 110 , 5984–5993 (2006)], we have used time‐dependent density functional theory (TD‐DFT) to study the electronic structure of neutral and charged ter‐fluorene with and without keto‐defect. We have characterized the excited states by site‐ and space‐based representations of the density matrix. For the defectless neutral species we found typical excitons, while the first excited states of the corresponding charged species represent long‐range oscillations of the electron or hole along the whole oligomer. For the neutral ketonized ter‐fluorene we found trapping of the excited electron. Similarly, the unpaired electron of the anion ground state is trapped. The excited state properties of the cation, however, are insensitive to the keto‐defect. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)