Probing the wave function and dynamics of the quintet multiexciton state with coherent control in a singlet fission material

Bayliss, S. L. , Weiss, L. R., Kraffert, F., Granger, D. B., Anthony, J. E., Behrends, J. and Bittl, R. (2020) Probing the wave function and dynamics of the quintet multiexciton state with coherent control in a singlet fission material. Physical Review X, 10(2), 021070. (doi: 10.1103/PhysRevX.10.021070)

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Abstract

High-spin states play a key role in chemical reactions found in nature. In artificial molecular systems, singlet fission produces a correlated triplet-pair state, a spin-bearing excited state that can be harnessed for more efficient solar-energy conversion and photocatalysis. In particular, triplet-pair states with overall quintet character (total spin S = 2 ) have been discovered, but many of the fundamental properties of these biexciton states remain unexplored. The net spin of these pair states makes spin-sensitive probes attractive for their characterization. Combined with their surprisingly long spin coherence (of order microseconds), this opens up techniques relying on coherent spin control. Here we apply coherent manipulation of triplet-pair states to (i) isolate their spectral signatures from coexisting free triplets and (ii) selectively couple quintet and triplet states to specific nuclear spins. Using this approach, we separate quintet and triplet transitions and extract the relaxation dynamics and hyperfine couplings of the fission-borne spin states. Our results highlight the distinct properties of correlated and free triplet excitons and demonstrate optically induced nuclear spin polarization by singlet fission.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Bayliss, Dr Sam
Authors: Bayliss, S. L., Weiss, L. R., Kraffert, F., Granger, D. B., Anthony, J. E., Behrends, J., and Bittl, R.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:Physical Review X
Publisher:American Physical Society
ISSN:2160-3308
Published Online:29 June 2020
Copyright Holders:Copyright © 2020 The Authors
First Published:First published in Physical Review X 10(2): 021070
Publisher Policy:Reproduced under a Creative Commons licence

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