Molecular versus excitonic disorder in individual artificial light-harvesting systems

Björn Kriete, Anna S Bondarenko, Riccardo Alessandri, Ilias Patmanidis, Victor V Krasnikov, Thomas L C Jansen, Siewert J Marrink, Jasper Knoester, Maxim S Pshenichnikov*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

2 Citations (Scopus)
63 Downloads (Pure)

Abstract

Natural light-harvesting antennae employ a dense array of chromophores to optimize energy transport via the formation of delocalized excited states (excitons), which are critically sensitive to spatio-energetic variations of the molecular structure. Identifying the origin and impact of such variations is highly desirable for understanding and predicting functional properties yet hard to achieve due to averaging of many overlapping responses from individual systems. Here, we overcome this problem by measuring the heterogeneity of synthetic analogues of natural antennae-self-assembled molecular nanotubes-by two complementary approaches: single-nanotube photoluminescence spectroscopy and ultrafast 2D correlation. We demonstrate remarkable homogeneity of the nanotube ensemble and reveal that ultrafast (∼50 fs) modulation of the exciton frequencies governs spectral broadening. Using multiscale exciton modeling, we show that the dominance of homogeneous broadening at the exciton level results from exchange narrowing of strong static disorder found for individual molecules within the nanotube. The detailed characterization of static and dynamic disorder at the exciton as well as the molecular level presented here opens new avenues in analyzing and predicting dynamic exciton properties, such as excitation energy transport.

Original languageEnglish
Article numberjacs.0c07392
Pages (from-to)18073-18085
Number of pages13
JournalJournal of the American Chemical Society
Volume142
Issue number42
Early online date26-Sep-2020
DOIs
Publication statusPublished - 21-Oct-2020

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