Exciton localization in semiconductor CNT


Svetlana V. Kilina, skilina@u.washington.edu, Department of Chemistry, University of Washington, Seattle, WA 98195-1700 and Sergei Tretiak, serg@lanl.gov, Theoretical Division, Los Alamos National Laboratory, MS B268, Los Alamos, NM 87545.
The extended investigations of both excitonic and vibrational effects in carbon nanotubes and their dependence on tube's chiralities and diameters has been done for wide range of tubes, using time-dependent Hartree Fock approach incorporating with semiempirical Hamiltonian. The first time, the localization of electronic excitations, so called self-trapped excitons, well known in conjugated polymers, has been detected in tubes with diameters ~0.1 nm. Our analysis identifies that the photo-excitation strongly affects the excited state geometry, especially in wide tubes. Experimental fluorescence spectrum were reproduced, showing the contribution of main phonon modes (G and RBM) coupled to electronic states.