Exciton annihilation in molecular aggregates suppressed through qu antum interference

Sarath Kumar, Ian S. Dunn, Shibin Deng, Tong Zhu, Qiuchen Zhao, Olivia F. Williams, Roel Tempelaar*, Libai Huang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Exciton–exciton annihilation (EEA), an important loss channel in optoelectronic devices and photosynthetic complexes, has conventionally been assumed to be an incoherent, diffusion-limited process. Here we challenge this assumption by experimentally demonstrating the ability to control EEA in molecular aggregates using the quantum phase relationships of excitons. We employed time-resolved photoluminescence microscopy to independently determine exciton diffusion constants and annihilation rates in two substituted perylene diimide aggregates featuring contrasting excitonic phase envelopes. Low-temperature EEA rates were found to differ by more than two orders of magnitude for the two compounds, despite comparable diffusion constants. Simulated rates based on a microscopic theory, in excellent agreement with experiments, rationalize this EEA behaviour based on quantum interference arising from the presence or absence of spatial phase oscillations of delocalized excitons. These results offer an approach for designing molecular materials using quantum interference where low annihilation can coexist with high exciton concentrations and mobilities. [Figure not available: see fulltext.].

Original languageEnglish (US)
Pages (from-to)1118-1126
Number of pages9
JournalNature chemistry
Volume15
Issue number8
DOIs
StatePublished - Aug 2023

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering

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