Theoretical analysis of the relaxation dynamics in perylene bisimide dimers excited by femtosecond laser pulses.
We present a model for the relaxation dynamics in perylene bisimide dimers, which is based on ab initio electronic structure and quantum dynamics calculations including effects of dissipation. The excited-state dynamics proceeds via a mixing of electronic states of local Frenkel and charge-transfer characters, which becomes effective upon a small distortion of the dimer geometry. In this way, it is possible to explain the fast depopulation of the photoexcited state, which we characterize by femtosecond transient absorption measurements. The combined theoretical and experimental analysis hints at a trapping mechanism, which involves nonadiabatic and dissipative dynamics in an excited-state vibronic manifold and provides an atomistic picture that might prove valuable for future design of photovoltaic materials.
Institut für Physikalische und Theoretische Chemie, Universität Würzburg , Hubland Campus Nord, Emil-Fischer-Strasse 42, 97074 Würzburg, Germany.
Alexander
A
Schubert
Mirjam
M
Falge
Martin
M
Kess
Volker
V
Settels
Stefan
S
Lochbrunner
Walter T
WT
Strunz
Frank
F
Würthner
Bernd
B
Engels
Volker
V
Engel
D019281:Dimerization; D007094:Imides / Q000737:chemistry*; D007834:Lasers; D008956:Models, Chemical; D056004:Molecular Dynamics Simulation; D010569:Perylene / Q000031:analogs & derivatives* / Q000737:chemistry; D011789:Quantum Theory; D055672:Static Electricity; D013816:Thermodynamics; D013997:Time Factors
D007094:Imides; C510697:perylene bisimide; D010569:Perylene