Quantum Dynamics of Exciton Transport and Dissociation in Multichromophoric Systems

Due to the subtle interplay of site-to-site electronic couplings, exciton delocalization, nonadiabatic effects, and vibronic couplings, quantum dynamical studies are needed to elucidate the details of ultrafast photoinduced energy and charge transfer events in organic multichromophoric systems. In this vein, we review an approach that combines first-principles parameterized lattice Hamiltonians with accurate quantum dynamical simulations using advanced multiconfigurational methods. Focusing on the elementary transfer steps in organic functional materials, we address coherent exciton migration and creation of charge transfer excitons in homopolymers, notably representative of the poly(3-hexylthiophene) material, as well as exciton dissociation at polymer:fullerene heterojunctions. We emphasize the role of coherent transfer, trapping effects due to high-frequency phonon modes, and thermal activation due to low-frequency soft modes that drive a diffusive dynamics.

Automated summary

The study of ultrafast photoinduced energy and charge transfer events in organic multichromophoric systems requires quantum dynamical studies due to the complex interplay of electronic couplings, exciton delocalization, nonadiabatic effects, and vibronic couplings. By combining first-principles lattice Hamiltonians with accurate quantum dynamical simulations, a detailed understanding of the coherent exciton migration, charge transfer exciton creation, and exciton dissociation in organic functional materials can be achieved. Key factors such as coherent transfer, trapping effects from high-frequency phonon modes, and thermal activation from low-frequency soft modes are highlighted in driving diffusive dynamics.