Influences of Exciton Diffusion and Exciton-Exciton Annihilation on Photon Emission Statistics of Carbon Nanotubes

TL;DR

This study investigates how exciton diffusion and exciton-exciton annihilation affect photon emission statistics in single-walled carbon nanotubes, revealing environmental influences and conditions for photon antibunching at room temperature.

Contribution

It provides new insights into the relationship between exciton dynamics and photon emission statistics in SWCNTs, highlighting environmental disorder effects and conditions for antibunching.

Findings

Linear correlation between exciton diffusion constant and Auger recombination coefficient.

Suppression of photon antibunching due to multiple exciton creation within laser spot.

Complete antibunching requires enhanced exciton-exciton annihilation rates.

Abstract

Pump-dependent photoluminescence imaging and 2nd order photon correlation studies have been performed on individual single-walled carbon nanotubes (SWCNTs) at room temperature that enable the extraction of both the exciton diffusion constant and the Auger recombination coefficient. A linear correlation between these is attributed to the effect of environmental disorder in setting the exciton mean free-path and capture-limited Auger recombination at this lengthscale. A suppression of photon antibunching is attributed to creation of multiple spatially non-overlapping excitons in SWCNTs whose diffusion length is shorter than the laser spot size. We conclude that complete antibunching at room temperature requires an enhancement of exciton-exciton annihilation rate that may become realizable in SWCNTs allowing for strong exciton localization.