Protonation effects on the branching ratio in photoexcited single-walled carbon nanotube dispersions

Jeffrey L. Blackburn, Timothy J. McDonald, Wyatt K. Metzger, Chaiwat Engtrakul, Garry Rumbles, Michael J. Heben

Research output: Contribution to journalArticlepeer-review

39 Citations (Scopus)


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 languageEnglish
Pages (from-to)1047-1054
Number of pages8
JournalNano letters
Issue number4
Publication statusPublished - Apr 1 2008

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

Fingerprint Dive into the research topics of 'Protonation effects on the branching ratio in photoexcited single-walled carbon nanotube dispersions'. Together they form a unique fingerprint.

Cite this