Speaker
Description
Charge transfer (CT) processes in donor–acceptor systems are central to photochemical and optoelectronic applications; however, the microscopic factors governing ultrafast transfer remain incompletely understood. Recent experiments on the PM605–TCNQ donor–acceptor system report ultrafast CT (~180 fs) outside an optical cavity. Upon coupling to cavity modes, the energetic driving force is reduced to approximately 0.5 eV compared to the bare system, leading to further acceleration of CT.
In this work, we have investigated different configurations using electronic structure methods and nonadiabatic dynamics. The ground-state optimized structure shows that the lowest CT lies significantly below S1 state, suggesting that the optimized structure alone does not favor ultrafast CT. However, other configurations show CT approaching S1 state and exhibit avoided crossings or conical intersections, enabling strong nonadiabatic coupling. Dynamics simulation reveal rapid population transfer from S1 to CT. Additionally, geometries slightly distorted from optimized configuration reveal proximity between S1 and higher CT states, facilitating alternative transfer pathways.
Building on these insights, we will investigate the accessibility of different configurations in solvent and establish possible pathway for ultrafast CT. Further we will investigate whether cavity-induced enhancements arise from intrinsic modifications of the system or from altered excitation pathways due to modified absorption inside cavity.