Nonradiative Recombination of Excitons in Carbon Nanotubes Mediated by Free Charge Carriers

TL;DR

This paper investigates how free charge carriers facilitate nonradiative exciton recombination in carbon nanotubes, revealing a thermal activation barrier and suggesting doping impacts exciton lifetimes and quantum yields.

Contribution

It introduces a model explaining nonradiative recombination mediated by free carriers in carbon nanotubes, highlighting the role of kinematic constraints and thermal activation.

Findings

Recombination rate by free electrons is comparable to two-exciton recombination.

Doping may reduce exciton lifetimes and quantum yields.

Thermal activation barrier influences recombination processes.

Abstract

Free electrons or holes can mediate the nonradiative recombination of excitons in carbon nanotubes. Kinematic constraints arising from the quasi one-dimensional nature of excitons and charge carriers lead to a thermal activation barrier for the process. However, a model calculation suggests that the rate for recombination mediated by a free electron is the same order of magnitude as that of two-exciton recombination. Small amounts of doping may contribute to the short exciton lifetimes and low quantum yields observed in carbon nanotubes.