Stone-Wales defects in nitrogen-doped C$_{20}$ fullerenes: Insight from $\textit{ab initio}$ calculations

TL;DR

This study uses density functional theory to analyze how Stone-Wales defects form in pure and nitrogen-doped C20 fullerenes, revealing how doping affects activation energies and stability at various temperatures.

Contribution

It provides detailed insights into the defect formation mechanisms and energy barriers in nitrogen-doped C20 fullerenes using ab initio calculations, highlighting the influence of nitrogen doping.

Findings

Nitrogen doping reduces the activation energy for defect formation.

Doped fullerenes remain kinetically stable at room temperature.

Stability decreases significantly at temperatures around 750 K.

Abstract

Density functional theory is applied to study the mechanism of the Stone-Wales defect formation in pure and nitrogen-doped dodecahedral C$_{20}$ fullerenes. The molecular structures of initial and defected cages as well as transition states dividing them are obtained. Depending on the number of nitrogen atoms and their relative position in the cage, Stone-Wales defect is formed through the single additional intermediate state or directly. The activation energy barrier of the defect formation reduces from 4.93 eV in pure C$_{20}$ to 2.98 eV in single-doped C$_{19}$N, and reaches $\sim$ 2 eV under further doping. All nitrogen-doped fullerenes considered possess high kinetic stability at room temperature. However, they become much less stable at temperatures of about 750 K that are typical for the fullerene annealing process.