Controlled Doping of Double Walled Carbon Nanotubes and Conducting Polymers in a Composite: An in situ Raman Spectroelectrochemical Study

TL;DR

This study uses in-situ Raman spectroelectrochemistry to investigate how doping affects the electronic structure of double-walled carbon nanotubes embedded in a conducting polymer, revealing selective doping effects on different nanotube layers.

Contribution

It provides new insights into the doping behavior of DWCNTs within a polymer matrix, highlighting layer-specific electronic changes during electrochemical doping.

Findings

Outer tubes of DWCNTs are partially doped by the polymer.

Inner tubes remain largely unaffected at low doping levels.

High doping levels induce changes in inner tubes similar to free DWCNTs.

Abstract

The interaction of double wall carbon nanotubes (DWCNTs) and the conducting polymer poly(3,4-ethylenedioxythiphene/polystyrenesulfonate (PEDOT/PSS) was studied by in-situ Raman spectroelectrochemistry. The mixing of DWCNTs with PEDOT/PSS caused a partial doping of the outer tube of DWCNTs, which was indicated by the relative change of the Raman intensity of the DWCNTs features. On the other hand, the bands corresponding to inner tubes of DWCNTs and to the polymer were almost untouched by assembling both species into a composite. The in situ Raman spectroelectrochemical experiments have shown that the changes in electronic structure of inner tubes of DWCNTs embedded in PEDOT/PSS matrix are dependent on the doping level. While at the low doping level of the composite, the Raman features of inner tubes of DWCNTs do not change significantly, at high doping level they reflect the changes caused by the applied electrochemical potential similar to that observed in the polymer-free DWCNTs.