Probing the ultrafast dynamics of excitons in single semiconducting carbon nanotubes

Excitonic states govern the optical response of low-dimensional nanomaterials and are key for a wide range of applications. Here, the authors investigate the exciton decay dynamics in single carbon nanotubes with few-exciton detection sensitivity. Excitonic states govern the optical spectra of low-dimensional semiconductor nanomaterials and their dynamics are key for a wide range of applications, such as in solar energy harvesting and lighting. Semiconducting single-walled carbon nanotubes emerged as particularly rich model systems for one-dimensional nanomaterials and as such have been investigated intensively in the past. The exciton decay dynamics in nanotubes has been studied mainly by transient absorption and time-resolved photoluminescence spectroscopy. Since different transitions are monitored with these two techniques, developing a comprehensive model to reconcile different data sets, however, turned out to be a challenge and remarkably, a uniform description seems to remain elusive. In this work, we investigate the exciton decay dynamics in single carbon nanotubes using transient interferometric scattering and time-resolved photoluminescence microscopy with few-exciton detection sensitivity and formulate a unified microscopic model by combining unimolecular exciton decay and ultrafast exciton-exciton annihilation on a time-scale down to 200 fs.

Automated summary

Excitonic states play a crucial role in the optical response of low-dimensional nanomaterials, and understanding their decay dynamics is important for various applications. In this study, the authors investigate the exciton decay dynamics in single carbon nanotubes using advanced techniques and develop a unified microscopic model. The findings provide insights into the behavior of excitons in nanotubes and contribute to the development of nanomaterials for energy harvesting and lighting.