Imaging Singlet Fission using Angle-Resolved Photoemission

Zachary H. Withers¹, Sergey Chernov¹, Jin Bakalis¹, Alice Kunin¹, Michael G. White², Gerd Schönhense³, and Thomas K. Allison<sup>1,2

1</sup>Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, USA

²Department of Chemistry, Stony Brook University, Stony Brook, New York 11794, USA

³Johannes Gutenberg-Universität, Institut für Physik, D-55099 Mainz, Germany



Many organic semiconductors exhibit a process called singlet fission, where an initially excited singlet exciton splits into two triplet excitons. This process makes these molecular materials attractive candidates for photovoltaic applications due to the additional charge carriers. However, the intermediate states involved in singlet exciton fission remain highly debated. High-performance time- and angle-resolved photoemission (tr-ARPES) using the combination of MHz repetition-rate high-harmonic generation (HHG) and time-of-flight momentum microscopy can be used to image the molecular orbitals involved in singlet fission [1,2,3]. We present results on the optimization of crystalline pentacene thin films for photoemission and initial tr-ARPES results elucidating the correlated triplet-pair intermediate states.



References

1. C. Corder, et al., Struct. Dyn. 5, 054301 (2018).

2. A. Kunin, et al., Phys. Rev. Letts. 130, 046202 (2023).

3. Wallauer, et al., Science, 371, 1056-1059, (2021).