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Vacancy control in acene blends links exothermic singlet fission to coherence
DOI:
10.1038/s41467-021-25395-9
Authors:
Clemens
Zeiser
(Universität Tübingen)
,
Chad
Cruz
(University of California at Riverside)
,
David R.
Reichman
(Columbia University)
,
Michael
Seitz
(University of Tübingen)
,
Jan
Hagenlocher
(University of Tübingen)
,
Eric L.
Chronister
(University of Nevada)
,
Christopher J.
Bardeen
(University of California at Riverside)
,
Roel
Tempelaar
(Columbia University; Northwestern University)
,
Katharina
Broch
(University of Tübingen)
Co-authored by industrial partner:
No
Type:
Journal Paper
Journal:
Nature Communications
, VOL 12
State:
Published (Approved)
Published:
August 2021
Diamond Proposal Number(s):
21899

Abstract: The fission of singlet excitons into triplet pairs in organic materials holds great technological promise, but the rational application of this phenomenon is hampered by a lack of understanding of its complex photophysics. Here, we use the controlled introduction of vacancies by means of spacer molecules in tetracene and pentacene thin films as a tuning parameter complementing experimental observables to identify the operating principles of different singlet fission pathways. Time-resolved spectroscopic measurements in combination with microscopic modelling enables us to demonstrate distinct scenarios, resulting from different singlet-to-triplet pair energy alignments. For pentacene, where fission is exothermic, coherent mixing between the photoexcited singlet and triplet-pair states is promoted by vibronic resonances, which drives the fission process with little sensitivity to the vacancy concentration. Such vibronic resonances do not occur for endothermic materials such as tetracene, for which we find fission to be fully incoherent; a process that is shown to slow down with increasing vacancy concentration.
Journal Keywords: Excited states
Subject Areas:
Materials,
Physics
Instruments:
I07-Surface & interface diffraction
Other Facilities: SixS at Soleil
Added On:
31/08/2021 10:24
Documents:
s41467-021-25395-9.pdf
Discipline Tags:
Surfaces
Physics
Materials Science
interfaces and thin films
Technical Tags:
Diffraction
X-ray Reflectivity (XRR)