Abstract
The ensemble PL quantum yield for raw single-walled carbon nanotubes (SWNTs) dispersed in sodium ctiolate (SC) is ∼5 times greater than that for the same raw SWNTs dispersed in sodium dodecyl sulfate (SDS) and ∼10 times greater than the quantum yield of purified SWNTs dispersed In SC. Absorbance and Raman spectra indicate that purified SC-dispersed SWNTs and raw SDS-dispersed SWNTs are hole-doped by protonation. Experiments comparing PL emission efficiency using E 2 and E 1 excitation show that protonation significantly affects the E 2 → E 1 relaxation process, which has typically been assumed to occur with unit efficiency. The E 2 → E 1 relaxation is 5 times more efficient in producing E 1 PL when SWNTs are unprotonated and protected by the SC surfactant. The results provide clear evidence that extrinsic factors, such as residual acids and the specific nature of SWNT-surfactant and SWNT-solvent interactions, can significantly affect measured SWNT luminescence quantum yields.
Original language | English |
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Pages (from-to) | 1047-1054 |
Number of pages | 8 |
Journal | Nano letters |
Volume | 8 |
Issue number | 4 |
DOIs | |
Publication status | Published - Apr 1 2008 |
ASJC Scopus subject areas
- Bioengineering
- Chemistry(all)
- Materials Science(all)
- Condensed Matter Physics
- Mechanical Engineering