We report on the generation of new low-energy photoluminescence (PL) bands in the spectra of semiconducting single-walled carbon nanotubes (SWNTs). The new bands, that are brightened because of local modifications of the nanotube structure or the metal adsorption on the SWNT surface, are attributed to PL from different nominally dark excitons that are "brightened" due to defect-induced mixing of states with different parity and/or spin. The effect of the created structural disorder on the dynamical properties of the emission is studied by time-resolved PL measurements revealing a significant reduction of the bright exciton lifetime. The lowest energy dark state has a longer lifetime and is not in thermal equilibrium with the bright state.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics