Abstract
Triplet pairs (TT) in crystalline molecular semiconductors have unique spin properties of interest for quantum information or enhancing solar photoconversion. The population and diffusion dynamics of TT have been the subject of recent studies, both in covalent dimers and in crystalline systems. Here, we monitor the triplet population in neat polycrystalline and amorphous films of a heteroacene with known TT spectral properties and tunable spin polarization depending on the intermolecular geometry. Transient measurements reveal an anomalous power dependence in polycrystalline films that we attribute to the fast diffusion and interaction of dissociated triplet pairs confined to one-dimensional stacks of strongly coupled molecules. The nongeminate triplet interaction after dephasing facilitates conversion to the triplet 3TT and eventually T1+S0. Amorphous films have no power dependence and proceed directly from 1TT to 3TT and subsequently T1+S0 via state mixing facilitated by nonparallel geometries and weak exchange coupling.
| Original language | English |
|---|---|
| Article number | e202400224 |
| Journal | ChemPhotoChem |
| Volume | 9 |
| Issue number | 3 |
| DOIs | |
| State | Published - Mar 2025 |
Bibliographical note
Publisher Copyright:© 2024 Wiley-VCH GmbH.
Funding
This work was funded by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Biosciences, and Geosciences under Contract No. DE-AC36-08GO28308 with NREL. L.H., A.D., S.S., and Q.M. acknowledge the support for fluorescence microscopy work from U.S. Department of Energy, Office of Basic Energy Sciences through award DE-SC0016356. This work was authored in part by Alliance for Sustainable Energy, Limited Liability Company, the manager and operator of the National Renewable Energy Laboratory. The views expressed in the article do not necessarily represent the views of the Department of Energy or the U.S. Government. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes. This work was funded by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Biosciences, and Geosciences under Contract No. DE\u2010AC36\u201008GO28308 with NREL. L.H., A.D., S.S., and Q.M. acknowledge the support for fluorescence microscopy work from U.S. Department of Energy, Office of Basic Energy Sciences through award DE\u2010SC0016356. This work was authored in part by Alliance for Sustainable Energy, Limited Liability Company, the manager and operator of the National Renewable Energy Laboratory. The views expressed in the article do not necessarily represent the views of the Department of Energy or the U.S. Government. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid\u2010up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes.
| Funders | Funder number |
|---|---|
| National Renewable Energy Laboratory | |
| DOE Basic Energy Sciences | |
| U.S. Government | |
| U.S. Department of Energy Oak Ridge National Laboratory U.S. Department of Energy National Science Foundation National Energy Research Scientific Computing Center | |
| Chemical Sciences, Geosciences, and Biosciences Division | DE-AC36-08GO28308, DE‐SC0016356 |
Keywords
- Annihilation
- Exciton
- Singlet fission
- Transport
- Triplet
ASJC Scopus subject areas
- Analytical Chemistry
- Physical and Theoretical Chemistry
- Organic Chemistry