Characterization of Single-Walled Carbon Nanotubes with Nodal Structural Defects

TL;DR

This study uses computational methods to characterize nodal defects in single-walled carbon nanotubes, revealing their impact on mechanical strength and electronic properties, and aligning well with experimental observations.

Contribution

It introduces a graphene-helix growth model to describe nodal defects and demonstrates their significant effects on SWNT properties using atomistic simulations.

Findings

Nodal defects lower tensile strength by four- to six-fold.

SWNTs with defects are more prone to damage under compression.

Nodal defects significantly reduce the electronic band-gap.

Abstract

Recently experiments showed that nodal structural defects are readily formed in the synthesis of single-walled carbon nanotubes (SWNTs) and consequently, SWNTs are likely to deviate from well-defined seamless tubular structures. Here, using graphene-helix growth model, we describe structural details of feasible nodal defects in SWNTs and investigate how mechanical and electronic properties of SWNTs would change in the presence of them using computational methods. Surprisingly atomistic simulations of SWNTs with nodal defects show excellent agreement with previous structural, tensile, and ball-milling experiments whose results cannot be explained using conventional models. The tensile failure of SWNTs with nodal defects requires about four- or six-fold lower strength than pristine ones and these SWNTs are comparatively prone to damage under a lateral compressive biting. We reveal that electronic band-gap of SWNT(12,8) would be remarkably reduced in the presence of nodal defects. This study strongly indicates universality of nodal defects in SWNTs requesting new theoretical framework in SWNT modelling for proper characteristics prediction.