Paramagnetic centers in graphene nanoribbons prepared from longitudinal unzipping of carbon nanotubes

TL;DR

This study uses ESR to identify paramagnetic centers in graphene nanoribbons created from carbon nanotubes, revealing details about their electronic structure and spin dynamics.

Contribution

It provides new insights into the paramagnetic centers and spin behavior in graphene nanoribbons derived from nanotubes, linking ESR signals to their electronic properties.

Findings

Presence of C-related dangling bond centers in GNRs

ESR signal broadening explained by hyperfine structure and conductivity effects

Spin dynamics follow a variable range hopping mechanism

Abstract

Electron spin resonance (ESR) investigation of graphene nanoribbons (GNRs) prepared through longitudinal unzipping of multiwalled carbon nanotubes (MWCNTs) indicates the presence of C-related dangling bond centers, exhibiting paramagnetic features. ESR signal broadening from pristine or oxidized graphene nanoribbons (OGNRs) is explained in terms of unresolved hyperfine structure, and in the case of reduced GNRs (RGNRs), the broadening of ESR signal can be due to enhancement in conductivity upon reduction. The spin dynamics observed from ESR linewidth-temperature data reflect a variable range hopping (VRH) mechanism through localized states, consistent with resistance-temperature data.