We show that new low-energy photoluminescence (PL) bands can be created in the spectra of semiconducting single-walled carbon nanotubes by intense pulsed excitation. The new bands are attributed to PL from different nominally dark excitons that are "brightened" because of a defect-induced mixing of states with different parity and/or spin. Time-resolved PL studies on single nanotubes reveal a significant reduction of the bright exciton lifetime upon brightening of the dark excitons. The lowest-energy dark state has longer lifetimes and is not in thermal equilibrium with the bright state.
|Autori:||Harutyunyan H; Gokus T; Green AA; Hersam MC; Allegrini M; Hartschuh A|
|Titolo:||Defect-induced Photoluminescence from Dark Excitonic States in Individual Single-Walled Carbon Nanotubes RID G-3268-2010 RID B-6512-2008 RID B-6739-2009|
|Anno del prodotto:||2009|
|Digital Object Identifier (DOI):||10.1021/nl9002798|
|Appare nelle tipologie:||1.1 Articolo in rivista|