Segalina, Alekos
Assfeld, Xavier
Monari, Antonio
Pastore, Mariachiara
Computational Modeling of Exciton Localization in
Self-Assembled Perylene Helices: Effects of Thermal Motion and Aggregate
Size
The effects of aggregation
on the excited-state properties in a
solution of perylene diimide self-assembled helix-like structures
of different sizes are investigated by means of first-principles density
functional theory (DFT), time-dependent DFT (TD-DFT), and classical
molecular dynamics (MD) simulations. Excited-state analysis based
on the one-particle transition density matrices is then used to study
the exciton nature and its delocalization as a function of the thermal
motion and aggregate size. Overall, the results point to a rather
small delocalization of the Frenkel excitonic state even in large
aggregates also related to a concerted motion of blocks of four monomers
along the MD trajectories. Although dynamic effects do not remarkably
affect the calculated position and shape of the absorption spectrum,
they cause the appearance of several low-energy states of charge-transfer
character and hence of weak intensity (dark states) that might be
populated along the ultrafast exciton relaxation process potentially
influencing the charge-separation processes in PDI-sensitized photoactive
heterointerfaces.
charge-transfer character;one-particle transition density matrices;Self-Assembled Perylene Helices;ultrafast exciton relaxation process;delocalization;Exciton Localization;absorption spectrum;Thermal Motion;Frenkel excitonic state;Excited-state analysis;results point;Computational Modeling;excited-state properties;DFT;low-energy states;perylene diimide self-assembled helix-like structures;first-principles density;Aggregate Size;exciton nature;charge-separation processes;MD trajectories;PDI-sensitized photoactive heterointerfaces;TD-DFT
2019-02-25
https://acs.figshare.com/articles/Computational_Modeling_of_Exciton_Localization_in_Self-Assembled_Perylene_Helices_Effects_of_Thermal_Motion_and_Aggregate_Size/7811534

10.1021/acs.jpcc.9b00494.s001