The Unique Origin of Colors of Armchair Carbon Nanotubes

TL;DR

This paper reveals that armchair carbon nanotubes exhibit size-dependent colors due to excitonic resonance, despite being metallic, highlighting a unique coloration mechanism distinct from other colloidal particles.

Contribution

It introduces a novel understanding of color origins in armchair carbon nanotubes, emphasizing their size-dependent excitonic resonance as a metallic yet color-producing phenomenon.

Findings

Distinct colors observed in armchair-enriched nanotube suspensions

Color depends on size-dependent excitonic resonance

Highlights a unique metallic coloration mechanism

Abstract

The colors of suspended metallic colloidal particles are determined by their size-dependent plasma resonance, while those of semiconducting colloidal particles are determined by their size-dependent band gap. Here, we present a novel case for armchair carbon nanotubes, suspended in aqueous medium, for which the color depends on their size-dependent excitonic resonance, even though the individual particles are metallic. We observe distinct colors of a series of armchair-enriched nanotube suspensions, highlighting the unique coloration mechanism of these one-dimensional metals.