Not dark yet for strong light-matter coupling to accelerate singlet fission dynamics

Polaritons are unique hybrid light-matter states that offer an alter-native way to manipulate chemical processes. In this work, we show that singlet fission dynamics can be accelerated under strong light-matter coupling. For superexchange-mediated singlet fission, state mixing speeds up the dynamics in cavities when the lower po-lariton is close in energy to the multiexcitonic state. This effect is more pronounced in non-conventional singlet fission materials in which the energy gap between the bright singlet exciton , the multiexcitonic state is large (> 0:1 eV). In this case, the dynamics is dominated by the polaritonic modes and not by the bare -mole-cule-like dark states, and, additionally, the resonant enhancement due to strong coupling is robust even for energetically broad molec-ular states. The present results provide a new strategy to expand the range of suitable materials for efficient singlet fission by making use of strong light-matter coupling.

Automated summary

In this work, it is shown that singlet fission dynamics can be accelerated under strong light-matter coupling. State mixing speeds up the dynamics when the lower polariton is close in energy to the multiexcitonic state. This effect is more pronounced in non-conventional singlet fission materials.