Effective Negative Diffusion of Singlet Excitons in Organic Semiconductors

Anton Matthijs Berghuis (Corresponding author), T. V. Raziman, Alexei Halpin, Shaojun Wang, Alberto G. Curto, Jaime Gómez Rivas (Corresponding author)

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Using diffraction-limited ultrafast imaging techniques, we investigate the propagation of singlet and triplet excitons in single-crystal tetracene. Instead of an expected broadening, the distribution of singlet excitons narrows on a nanosecond time scale after photoexcitation. This narrowing results in an effective negative diffusion in which singlet excitons migrate toward the high-density region, eventually leading to a singlet exciton distribution that is smaller than the laser excitation spot. Modeling the excited-state dynamics demonstrates that the origin of the anomalous diffusion is rooted in nonlinear triplet–triplet annihilation (TTA). We anticipate that this is a general phenomenon that can be used to study exciton diffusion and nonlinear TTA rates in semiconductors relevant for organic optoelectronics.
Original languageEnglish
Pages (from-to)1360-1366
Number of pages7
JournalThe Journal of Physical Chemistry Letters
Volume12
Issue number4
DOIs
Publication statusPublished - 28 Jan 2021

Bibliographical note

PMID: 33507078

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