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Broch K, Dieterle J, Branchi F, Hestand NJ, Olivier Y, Tamura H, Cruz C, Nichols VM, Hinderhofer A, Beljonne D, Spano FC, Cerullo G, Bardeen CJ, Schreiber F. Robust singlet fission in pentacene thin films with tuned charge transfer interactions. Nat Commun 2018; 9:954. [PMID: 29507287 PMCID: PMC5838205 DOI: 10.1038/s41467-018-03300-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 01/29/2018] [Indexed: 02/07/2023] Open
Abstract
Singlet fission, the spin-allowed photophysical process converting an excited singlet state into two triplet states, has attracted significant attention for device applications. Research so far has focused mainly on the understanding of singlet fission in pure materials, yet blends offer the promise of a controlled tuning of intermolecular interactions, impacting singlet fission efficiencies. Here we report a study of singlet fission in mixtures of pentacene with weakly interacting spacer molecules. Comparison of experimentally determined stationary optical properties and theoretical calculations indicates a reduction of charge-transfer interactions between pentacene molecules with increasing spacer molecule fraction. Theory predicts that the reduced interactions slow down singlet fission in these blends, but surprisingly we find that singlet fission occurs on a timescale comparable to that in pure crystalline pentacene. We explain the observed robustness of singlet fission in such mixed films by a mechanism of exciton diffusion to hot spots with closer intermolecular spacings.
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Affiliation(s)
- K Broch
- Institute of Applied Physics and Center for Light Matter Interactions, Sensors and Analytics, LISA+, University of Tübingen, Auf der Morgenstelle 10, 72076, Tübingen, Germany.
- Fritz-Haber Institute of the Max-Planck Society, Faradayweg 4-6, 14195, Berlin, Germany.
| | - J Dieterle
- Institute of Applied Physics and Center for Light Matter Interactions, Sensors and Analytics, LISA+, University of Tübingen, Auf der Morgenstelle 10, 72076, Tübingen, Germany
| | - F Branchi
- IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Milano, 20133, Italy
| | - N J Hestand
- Department of Chemistry, Temple University, Philadelphia, PA, 19122, USA
| | - Y Olivier
- Laboratory for Chemistry of Novel Materials, University of Mons, Place du Parc 20, 7000, Mons, Belgium
| | - H Tamura
- Department of Chemical System Engineering, The University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo, 113-8656, Japan
| | - C Cruz
- Department of Chemistry, University of California at Riverside, 501 Big Springs Rd, Riverside, CA, 92521, USA
| | - V M Nichols
- Department of Chemistry, University of California at Riverside, 501 Big Springs Rd, Riverside, CA, 92521, USA
| | - A Hinderhofer
- Institute of Applied Physics and Center for Light Matter Interactions, Sensors and Analytics, LISA+, University of Tübingen, Auf der Morgenstelle 10, 72076, Tübingen, Germany
| | - D Beljonne
- Laboratory for Chemistry of Novel Materials, University of Mons, Place du Parc 20, 7000, Mons, Belgium
- School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, GA, 30332-0400, USA
| | - F C Spano
- Department of Chemistry, Temple University, Philadelphia, PA, 19122, USA
| | - G Cerullo
- IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Milano, 20133, Italy
| | - C J Bardeen
- Department of Chemistry, University of California at Riverside, 501 Big Springs Rd, Riverside, CA, 92521, USA
| | - F Schreiber
- Institute of Applied Physics and Center for Light Matter Interactions, Sensors and Analytics, LISA+, University of Tübingen, Auf der Morgenstelle 10, 72076, Tübingen, Germany
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