Exciton dynamics of a fused ring π-conjugated nonfullerene molecule based on dithienonaphthobisthiadiazole

Abstract Herein, we have studied the exciton dynamics of a novel fused ring π -conjugated molecule (YS3) in solution and film states by spectroscopic measurements. This molecule incorporates dithienonaphthobisthiadiazole as a core unit that is a two-dimensionally π -extended fused ring. As a result, we found a long exciton lifetime in YS3 films originating from reduced radiative and nonradiative transitions. This is partly because radiative deactivation is effectively suppressed because of the dipole-forbidden transition in H-aggregates and partly because rotational deactivation is effectively suppressed in the crystalline film state.