Abstract
Triplet population dynamics of solution cast films of isolated polymorphs of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-Pn) provide quantitative experimental evidence that triplet excitation energy transfer is the dominant mechanism for correlated triplet pair (CTP) separation during singlet fission. Variations in CTP separation rates are compared for polymorphs of TIPS-Pn with their triplet diffusion characteristics that are controlled by their crystal structures. Since triplet energy transfer is a spin-forbidden process requiring direct wavefunction overlap, simple calculations of electron and hole transfer integrals are used to predict how molecular packing arrangements would influence triplet transfer rates. The transfer integrals reveal how differences in the packing arrangements affect electronic interactions between pairs of TIPS-Pn molecules, which are correlated with the relative rates of CTP separation in the polymorphs. These findings suggest that relatively simple computations in conjunction with measurements of molecular packing structures may be used as screening tools to predict a priori whether new types of singlet fission sensitizers have the potential to undergo fast separation of CTP states to form multiplied triplets.
Original language | English |
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Article number | 1703929 |
Journal | Advanced Functional Materials |
Volume | 27 |
Issue number | 46 |
DOIs | |
State | Published - Dec 8 2017 |
Bibliographical note
Funding Information:C.G. and G.S.D. contributed equally to this work. C.G., G.S.D., A.R., and J.B.A. thank the Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences of the U.S. Department of Energy through Grant DE-SC0008120 for support of this work. I.D. acknowledges support from the Soltis faculty support award and the Ralph E. Powe junior faculty award from Oak Ridge Associated Universities. J.E.A. and M.M.P. thank the National Science Foundation (CMMI-1255494) for supporting semiconductor synthesis. Y.L. and E.D.G. acknowledge financial support from the Office of Naval Research under Grant N000141410532. The Advanced Light Source is an Office of Science User Facility operated for the U.S. Department of Energy Office of Science by Lawrence Berkeley National Laboratory and is supported by the U.S. Department of Energy under Contract DE-AC02-05CH11231. C.G. thanks Ryan Pensack, Geoff Purdum, and Brian Conway for helpful discussions.
Publisher Copyright:
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Keywords
- molecular electronics
- singlet fission
- structure–property relationships
- triplet transfer
ASJC Scopus subject areas
- Chemistry (all)
- Materials Science (all)
- Condensed Matter Physics