Parallel versus Twisted Pentacenes: Conformational Impact on Singlet Fission

Papadopoulos I, Reddy SR, Coto PB, Lehnherr D, Thiel D, Thoss M, Tykwinski RR, Guldi DM (2022)

Publication Type: Journal article

Publication year: 2022

Journal

Journal of Physical Chemistry Letters American Chemical Society

Pages Range: 5094-5100

DOI: 10.1021/acs.jpclett.2c01395

Abstract

We placed two pentacene chromophores at the termini of a diacetylene linker to investigate the impact of excitation wavelength, conformational flexibility, and vibronic coupling on singlet fission. Photoexcitation of the low-energy absorption results in a superposed mixture of states, which transform on an ultrafast time-scale into a spin-correlated and vibronically coupled/hot delocalized triplet pair 1(T1T1)deloc. Regardless of temperature, the lifetime for 1(T1T1)deloc is less than 2 ps. In contrast, photoexcitation of the high-energy absorption results in the formation of 1(T1T1)deloc lasting 1.0 ps, which then decays at room temperature within 4 ps via triplet-triplet annihilation. Lowering the temperature enables 1(T1T1)deloc to delocalize and vibronically decouple, in turn affording 1(T1T1)loc. In addition, our results suggest that the quasi-free rotation at the diacetylene spacer may lead to twisted conformations with very low SF quantum yields, highlighting the need of controlling this structural aspect in the design of new singlet fission active molecules.

Authors with CRIS profile

Ilias Papadopoulos Lehrstuhl für Physikalische Chemie I Dominik Thiel Lehrstuhl für Physikalische Chemie I Dirk Michael Guldi Lehrstuhl für Physikalische Chemie I

Involved external institutions

Central University of Rajasthan IN India (IN) Spanish National Research Council / Consejo Superior de Investigaciones Científicas (CSIC) ES Spain (ES) University of Alberta CA Canada (CA) Albert-Ludwigs-Universität Freiburg DE Germany (DE)

How to cite

APA:

Papadopoulos, I., Reddy, S.R., Coto, P.B., Lehnherr, D., Thiel, D., Thoss, M.,... Guldi, D.M. (2022). Parallel versus Twisted Pentacenes: Conformational Impact on Singlet Fission. Journal of Physical Chemistry Letters, 5094-5100. https://doi.org/10.1021/acs.jpclett.2c01395

MLA:

Papadopoulos, Ilias, et al. "Parallel versus Twisted Pentacenes: Conformational Impact on Singlet Fission." Journal of Physical Chemistry Letters (2022): 5094-5100.

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