Super-localization of excitons in carbon nanotubes at cryogenic temperature

TL;DR

This study uses super-resolved microscopy to analyze exciton localization in single-wall carbon nanotubes at cryogenic temperatures, revealing how disorder induces quantum confinement effects and alters optical properties.

Contribution

It provides the first hyperspectral imaging of exciton self-localization at the single nanotube level, including statistical analysis and numerical modeling of localized states.

Findings

Localization causes nearly 0D optical behaviors.

Disorder leads to discretized excitonic spectra.

Exciton diffusion is significantly affected by interface disorder.

Abstract

At cryogenic temperature and at the single emitter level, the optical properties of single-wall carbon nanotubes depart drastically from that of a one-dimensional (1D) object. In fact, the (usually unintentional) localization of excitons in local potential wells leads to nearly 0D behaviors such as photon antibunching, spectral diffusion, inhomogeneous broadening, etc. Here, we present an hyperspectral imaging of this exciton self-localization effect at the single nanotube level using a super-resolved optical microscopy approach. We report on the statistical distribution of the traps localization, depth and width. We use a quasi-resonant photoluminescence excitation approach to probe the confined quantum states. Numerical simulations of the quantum states and exciton diffusion show that the excitonic states are deeply modified by the interface disorder inducing a remarkable discretization of the excitonic absorption spectrum and a quenching of the free 1D exciton absorption.