(Invited) High-Yield and Long-Lived Individual Triplet Exciton Generation Using Covalently-Linked Tetracene Dimers through Intramolecular Singlet Fission

Abstract

Singlet fission (SF) is a multi-exciton generation process in two neighboring organic chromophores (S1 + S0) where two individual triplet excitons (T1 + T1) are generated from one-photon absorption through a correlated triplet pair (TT) (see: the following equation). Therefore, SF is highly promising for construction of next-generation light energy conversion systems.S1 + S0 → TT → T1 + T1 In addition to the close interaction of two neighboring chromophores, energy-level matching condition between a singlet and two triplet states: [E(S1) ≥ 2E(T1)] are required for efficient SF. Acene derivatives such as pentacene satisfy the above condition. However, the number of high-yield and long-lived triplet excited states through SF using tetracene derivatives is extremely limited because of the acceleration of the reverse reaction: triplet-triplet annihilation.1-2 Namely, the precise structural control of orientation and distance between two nearby tetracene units is required for long-lived individual triplets through SF. In this presentation, we mainly focus on the high-yield and long-lived individual triplet exciton generation through intramolecular SF (ISF) using a series of phenylene-spacer-bridged tetracene dimers.3 References Nakamura, S.; Sakai, H.; Nagashima, H.; Kobori, Y.; Tkachenko, N. V.; Hasobe, T. ACS Energy Lett. 2019, 4, 26-31.Saegusa, T.; Sakai, H.; Nagashima, H.; Kobori, Y.; Tkachenko, N. V.; Hasobe, T. J. Chem. Soc. 2019, 141, 14720-14727.Nakamura, S.; Sakai, H.; Nagashima, H.; Fuki, M.; Onishi, K.; Khan, R.; Kobori, Y.; Tkachenko, N. V.; Hasobe, T. Phys. Chem. C 2021, 125, 18287-18296.