Characterization of the Electronic Properties of Single‐Walled Carbon Nanotubes Filled with an Electron Donor-Rubidium Iodide: Multifrequency Raman and X‐ray Photoelectron Spectroscopy Studies

Abstract

Single-walled carbon nanotubes (SWCNTs) with a mean diameter of 1.4 nm are filled with rubidium iodide. The filling of nanotubes is proved by high-resolution scanning transmission electron microscopy. The chemical composition of the filler is confirmed by X-ray photoelectron spectroscopy (XPS). The electronic properties of the filled SWCNTs are studied by XPS and Raman spectroscopy. The encapsulated salt leads to n-doping of nanotubes. The detailed multifrequency Raman spectroscopy investigation of the alteration of Raman modes of SWCNTs upon filling is conducted. The doping-induced changes in the radial breathing mode and G-band are revealed. It is found that these changes differ for the metallic and semiconducting SWCNTs. The obtained data and revealed trends are expected to be helpful for forthcoming studies to interpret the observed changes in Raman spectra of filled metallic and semiconducting SWCNTs.