Dynamics of charged excitons in electronically and morphologically homogeneous single-walled carbon nanotubes

Yusong Bai, Jean-Hubert Olivier, George Bullard, Chaoren Liu, Michael J. Therien

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

The trion, a three-body charge-exciton bound state, offers unique opportunities to simultaneously manipulate charge, spin, and excitation in one-dimensional single-walled carbon nanotubes (SWNTs) at room temperature. Effective exploitation of trion quasi-particles requires fundamental insight into their creation and decay dynamics. Such knowledge, however, remains elusive for SWNT trion states, due to the electronic and morphological heterogeneity of commonly interrogated SWNT samples, and the fact that transient spectroscopic signals uniquely associated with the trion state have not been identified. Here, we prepare length-sorted SWNTs and precisely control charge-carrier-doping densities to determine trion dynamics using femtosecond pump–probe spectroscopy. Identification of the trion transient absorptive hallmark enables us to demonstrate that trions (i) derive from a precursor excitonic state, (ii) are produced via migration of excitons to stationary hole-polaron sites, and (iii) decay in a first-order manner. Importantly, under appropriate carrier-doping densities, exciton-to-trion conversion in SWNTs can approach 100% at ambient temperature. Our findings open up possibilities for exploiting trions in SWNT optoelectronics, ranging from photovoltaics and photodetectors to spintronics.

Original languageEnglish (US)
Pages (from-to)674-679
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume115
Issue number4
DOIs
StatePublished - Jan 23 2018
Externally publishedYes

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Keywords

  • Charge
  • Dynamics
  • Exciton
  • Single-walled carbon nanotube
  • Trion

ASJC Scopus subject areas

  • General

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