Defect-induced photoluminescence from dark excitonic states in individual single-walled carbon nanotubes.
basic_science · Level V
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- Record sourced from PubMed, PMID 19331347.
- Also identified by DOI 10.1021/nl9002798.
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Abstract
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.