Environmental Effect on the UV Optical Absorption of Single-Walled Carbon Nanotubes

TL;DR

This study investigates how the dielectric environment affects the UV optical absorption of single-walled carbon nanotubes, revealing spectral changes linked to surface plasmons and questioning traditional attributions of absorption features.

Contribution

It provides new insights into the environmental dependence of UV absorption features in carbon nanotubes and challenges existing interpretations of the ~4.5 eV absorption component.

Findings

The 5.0 - 5.3 eV component shows significant spectral changes with environment.

The ~4.5 eV component remains unchanged across different dielectric environments.

The ~4.5 eV feature may be related to graphite interband transitions.

Abstract

We studied optical absorption of single-walled carbon nanotubes by varying the dielectric environment. For the two different components of the broad UV absorption feature conventionally referred to as the pi-plasmon, we find that the component at 5.0 - 5.3 eV exhibits remarkable spectral changes, based on which we attribute this to a dipolar radial surface plasmon. However, the component at ~4.5 eV remains unchanged, raising a fundamental question as to its conventional attribution. We discuss its relation with the absorption feature at ~4.5 eV in graphite arising from an interband transition.