Raman spectroscopy of iodine-doped double-walled carbon nanotubes

TL;DR

This study uses Raman spectroscopy to analyze iodine-doped double-walled carbon nanotubes, revealing charge transfer primarily affecting the outer tubes and identifying poly-iodine anions.

Contribution

It provides detailed Raman spectral analysis of iodine-doped DWCNTs and clarifies the charge transfer mechanism involving only the outer tubes.

Findings

Charge transfer occurs mainly in outer tubes.

Poly-iodine anions are identified.

Raman spectra changes upon doping are characterized.

Abstract

We present a Raman spectroscopy study of iodine-intercalated (p-type-doped) double-walled carbon nanotubes. Double-walled carbon nanotubes (DWCNTs) are synthesized by catalytic chemical vapor deposition and characterized by Raman spectroscopy. The assignment of the radial breathing modes and the tangential modes of pristine DWCNTs is done in the framework of the bond polarization theory, using the spectral moment method. The changes in the Raman spectrum upon iodine doping are analyzed. Poly-iodine anions are identi- fied, and the Raman spectra reveal that the charge transfer between iodine and DWCNTs only involves the outer tubes.