Theoretical Study on Singlet Fission Dynamics in Pentacene Ring‐Shaped Aggregate Models with Different Configurations

Abstract

AbstractUsing the quantum master equation method, we investigate size and monomer configuration dependences of singlet fission (SF) in pentacene J‐ and H‐type ring‐shaped aggregate (N‐mer) models. Interestingly, it is found that SF rates in the J‐aggregate models monotonically decrease with increasing N, while those in the H‐aggregate models show different variation behaviors depending on the parity of N, where the H‐type pentamer model exhibits the maximum SF rate. It is also found that correlated triplet‐pair yields in the J‐aggregate models rapidly increase from ∼0.45 toward 1, while those in the H‐aggregate gradually decrease from ∼0.96 toward 0. These features are explained by relative relaxation factor analysis between adiabatic states and by the point group symmetry of the ring‐shaped aggregate models. The present results contribute to a deeper understanding of the correlation between the aggregate size, monomer configuration and SF dynamics, and thus to constructing new design guidelines for highly efficient SF ring‐shaped aggregates.