Temperature dependence of exciton recombination in semiconducting single-wall carbon nanotubes

TL;DR

This study investigates how exciton recombination in semiconducting single-wall carbon nanotubes varies with temperature, revealing distinct decay processes and their underlying mechanisms through time-resolved photoluminescence experiments.

Contribution

It provides a detailed analysis of temperature-dependent exciton recombination dynamics and introduces a phenomenological model explaining photoluminescence variations across temperatures.

Findings

Fast decay is temperature independent, linked to residual bundles.

Slow decay shows strong temperature dependence, dominated by non-radiative processes.

Room temperature luminescence is unaffected by dark/bright excitonic coupling.

Abstract

We study the excitonic recombination dynamics in an ensemble of (9,4) semiconducting single-wall carbon nanotubes by high sensitivity time-resolved photo-luminescence experiments. Measurements from cryogenic to room temperature allow us to identify two main contributions to the recombination dynamics. The initial fast decay is temperature independent and is attributed to the presence of small residual bundles that create external non-radiative relaxation channels. The slow component shows a strong temperature dependence and is dominated by non-radiative processes down to 40 K. We propose a quantitative phenomenological modeling of the variations of the integrated photoluminescence intensity over the whole temperature range. We show that the luminescence properties of carbon nanotubes at room temperature are not affected by the dark/bright excitonic state coupling.