Improved Electrical Conductivity of Copper and Nitrogen Functionalized Carbon Nanotubes

TL;DR

This study uses first-principles calculations to show that doping carbon nanotubes with copper and nitrogen significantly enhances their electrical conductivity, especially in semiconducting variants, aiding the development of high-performance CNT composites.

Contribution

It provides a detailed theoretical analysis of how copper and nitrogen doping improve CNT conductivity, highlighting the impact of specific functional groups like N-pyrrolic.

Findings

Copper and nitrogen doping significantly increase CNT conductivity.

N-pyrrolic groups cause up to a 30-fold increase in conductivity.

Results align with recent experimental data on doped CNTs.

Abstract

In this work, we investigate the electrical conductivity of carbon nanotubes (CNTs), with a particular focus on the effects of doping. Using a first-principles approach, we study the electronic structure, phonon dispersion, and electron-phonon scattering to understand the finite-temperature electrical transport properties in CNTs. Our study covers both prototypical metallic and semiconducting CNTs, with special emphasis on the influence of typical defects such as vacancies and the incorporation of copper or nitrogen, such as pyridinic N, pyrrolic N, graphitic N, and oxidized N. Our theoretical study shows significant improvements in the electrical conduction properties of copper-CNT composites, especially when semiconducting CNTs are functionalized with nitrogen. Doping is found to cause significant changes in the electronic density of states near the Fermi level, which affects the electrical conductivity. Calculations show that certain types of functional groups, such as N-pyrrolic, result in a ~30-fold increase in the conductivity of semiconducting CNTs compared to Cu-incorporated CNTs alone. For metallic CNTs, the conductivity is in agreement with existing experimental data, and our prediction of significant increases in conductivity with N-pyrrolic functional group is consistent with recent experimental results, demonstrating the effectiveness of doping in modifying conductivity. Our study provides valuable insight into the electronic properties of doped CNTs and contributes to the development of ultra-high conductivity CNT composites.