Evidence for Charge-Transfer Mediation in the Primary Events of Singlet Fission in a Weakly Coupled Pentacene Dimer

Basel B, Zirzlmeier J, Hetzer C, Seelam RR, Phelan BT, Krzyaniak MD, Volland M, Brana Coto P, Young RM, Clark T, Thoss M, Tykwinski R, Wasielewski MR, Guldi DM (2018)

Publication Status: Published

Publication Type: Journal article

Publication year: 2018

Journal

Chem Elsevier (Cell Press)

Publisher: CELL PRESS

Book Volume: 4

Pages Range: 1092-1111

Journal Issue: 5

DOI: 10.1016/j.chempr.2018.04.006

Abstract

Singlet fission (SF) is a process that converts one singlet excited state into two triplet states. The mechanism of SF is still not well understood. Here, we report on the use of a combination of transient absorption and electron paramagnetic resonance spectroscopies in conjunction with theoretical calculations to probe SF in a pentacene dimer linked by a non-conjugated, 1,4-diethynylbicyclo[2.2.2]octane spacer. Next to observing the key intermediates in solution-based SF, including the formation and decay of a quintet state that precedes formation of the pentacene triplet excitons, we demonstrate that the coupling is sufficiently weak that SF is essentially inoperative in non-polar media. Transitioning to a polar medium, however, amplifies the coupling strength such that SF becomes operative and supports long triplet lifetimes. Our results offer strong evidence for a charge-transfer mediation and, in turn, provide a solid framework for decoding the complete mechanism of SF in systems beyond pentacene.

Authors with CRIS profile

Bettina Basel Lehrstuhl für Physikalische Chemie I Johannes Zirzlmeier Lehrstuhl für Physikalische Chemie I Constantin Hetzer Lehrstuhl für Anorganische und Allgemeine Chemie Rajagopala Reddy Seelam Professur für Theoretische Physik mit dem Schwerpunkt Molekulare Materialien Michel Volland Lehrstuhl für Physikalische Chemie I Pedro Brana Coto Professur für Theoretische Physik mit dem Schwerpunkt Molekulare Materialien Timothy Clark Computer-Chemie-Centrum Michael Thoss Professur für Theoretische Physik mit dem Schwerpunkt Molekulare Materialien Rik Tykwinski Lehrstuhl für Organische Chemie I Dirk Michael Guldi Lehrstuhl für Physikalische Chemie I

Involved external institutions

Northwestern University US United States (USA) (US)

How to cite

APA:

Basel, B., Zirzlmeier, J., Hetzer, C., Seelam, R.R., Phelan, B.T., Krzyaniak, M.D.,... Guldi, D.M. (2018). Evidence for Charge-Transfer Mediation in the Primary Events of Singlet Fission in a Weakly Coupled Pentacene Dimer. Chem, 4(5), 1092-1111. https://dx.doi.org/10.1016/j.chempr.2018.04.006

MLA:

Basel, Bettina, et al. "Evidence for Charge-Transfer Mediation in the Primary Events of Singlet Fission in a Weakly Coupled Pentacene Dimer." Chem 4.5 (2018): 1092-1111.

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