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.

Details

Title
Robust singlet fission in pentacene thin films with tuned charge transfer interactions
Author
Broch, K 1 ; Dieterle, J 2 ; Branchi, F 3 ; Hestand, N J 4   VIAFID ORCID Logo  ; Olivier, Y 5 ; Tamura, H 6 ; Cruz, C 7 ; Nichols, V M 7 ; Hinderhofer, A 2 ; Beljonne, D 8 ; Spano, F C 4 ; Cerullo, G 3 ; Bardeen, C J 7 ; Schreiber, F 2 

1  Institute of Applied Physics and Center for Light Matter Interactions, Sensors and Analytics, LISA+, University of Tübingen, Tübingen, Germany; Fritz-Haber Institute of the Max-Planck Society, Berlin, Germany 
2  Institute of Applied Physics and Center for Light Matter Interactions, Sensors and Analytics, LISA+, University of Tübingen, Tübingen, Germany 
3  IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Milano, Italy 
4  Department of Chemistry, Temple University, Philadelphia, PA, USA 
5  Laboratory for Chemistry of Novel Materials, University of Mons, Mons, Belgium 
6  Department of Chemical System Engineering, The University of Tokyo, Tokyo, Japan 
7  Department of Chemistry, University of California at Riverside, Riverside, CA, USA 
8  Laboratory for Chemistry of Novel Materials, University of Mons, Mons, Belgium; School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, GA, USA 
Pages
1-9
Publication year
2018
Publication date
Mar 2018
Publisher
Nature Publishing Group
e-ISSN
20411723
Source type
Scholarly Journal
Language of publication
English
DOI
https://doi.org/10.1038/s41467-018-03300-1
ProQuest document ID
2010823924
Copyright
© 2018. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.