Impact of electron delocalization on the nature of the charge-transfer states in model pentacene/C60 Interfaces: A density functional theory study
Aziz, Saadullah Gary
Coropceanu, Veaceslav P.
KAUST DepartmentKAUST Solar Center (KSC)
Physical Sciences and Engineering (PSE) Division
Materials Science and Engineering Program
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AbstractElectronic delocalization effects have been proposed to play a key role in photocurrent generation in organic photovoltaic devices. Here, we study the role of charge delocalization on the nature of the charge-transfer (CT) states in the case of model complexes consisting of several pentacene molecules and one fullerene (C60) molecule, which are representative of donor/acceptor heterojunctions. The energies of the CT states are examined by means of time-dependent density functional theory (TD-DFT) using the long-range-corrected functional, ωB97X, with an optimized range-separation parameter, ω. We provide a general description of how the nature of the CT states is impacted by molecular packing (i.e., interfacial donor/acceptor orientations), system size, and intermolecular interactions, features of importance in the understanding of the charge-separation mechanism.
PublisherAmerican Chemical Society (ACS)