Cooperative Singlet and Triplet Exciton Transport in Tetracene Crystals Visualized by Ultrafast Microscopy

Yan Wan, Zhi Guo, Tong Zhu, Suxia Yan, Justin Johnson, Libai Huang

Research output: Contribution to journalArticlepeer-review

185 Scopus Citations

Abstract

Singlet fission presents an attractive solution to overcome the Shockley-Queisser limit by generating two triplet excitons from one singlet exciton. However, although triplet excitons are long-lived, their transport occurs through a Dexter transfer, making them slower than singlet excitons, which travel by means of a Förster mechanism. A thorough understanding of the interplay between singlet fission and exciton transport is therefore necessary to assess the potential and challenges of singlet-fission utilization. Here, we report a direct visualization of exciton transport in single tetracene crystals using transient absorption microscopy with 200 fs time resolution and 50 nm spatial precision. These measurements reveal a new singlet-mediated transport mechanism for triplets, which leads to an enhancement in effective triplet exciton diffusion of more than one order of magnitude on picosecond to nanosecond timescales. These results establish that there are optimal energetics of singlet and triplet excitons that benefit both singlet fission and exciton diffusion.

Original languageAmerican English
Pages (from-to)785-792
Number of pages8
JournalNature Chemistry
Volume7
Issue number10
DOIs
StatePublished - 2015

Bibliographical note

Publisher Copyright:
© 2015 Macmillan Publishers Limited. All rights reserved.

NREL Publication Number

  • NREL/JA-5900-64151

Keywords

  • diffusion
  • photovoltaics (PV)
  • singlet fission
  • solar-photochemistry
  • tetracene

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