Identification of excitonic phonon sideband by photoluminescence spectroscopy of single-walled carbon-13 nanotubes

TL;DR

This study uses photoluminescence and Raman spectroscopy to identify excitonic phonon sidebands in single-walled carbon-13 nanotubes, confirming isotope effects on exciton-phonon interactions.

Contribution

It provides direct experimental evidence of excitonic phonon sidebands and their isotope shifts in carbon nanotubes, advancing understanding of exciton-phonon coupling.

Findings

Clear identification of excitonic phonon sideband in carbon-13 nanotubes.

Observed Raman shift downshift consistent with isotope mass change.

Confirmed strong exciton-phonon interaction through isotope shift analysis.

Abstract

We have studied photoluminescence (PL) and resonant Raman scatterings of single-walled carbon nanotubes (SWNTs) consisting of carbon-13 (SW13CNTs) synthesized from a small amount of isotopically modified ethanol. There was almost no change in the Raman spectra shape for SW13CNTs except for a downshift of the Raman shift frequency by the square-root of the mass ratio 12/13. By comparing photoluminescence excitation (PLE) spectra of SW13CNTs and normal SWNTs, the excitonic phonon sideband due to strong exciton-phonon interaction was clearly identified with the expected isotope shift.