10.1021/acs.jpcc.9b00494.s001
Alekos Segalina
Xavier Assfeld
Antonio Monari
Mariachiara Pastore
Computational Modeling of Exciton Localization in
Self-Assembled Perylene Helices: Effects of Thermal Motion and Aggregate
Size
2019
American Chemical Society
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 00:00:00
article
https://acs.figshare.com/articles/Computational_Modeling_of_Exciton_Localization_in_Self-Assembled_Perylene_Helices_Effects_of_Thermal_Motion_and_Aggregate_Size/7811534
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.