Dresden 2026 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 22: Hybrid, Organic and Perovskite Optoelectronics and Photovoltaics I
CPP 22.4: Vortrag
Dienstag, 10. März 2026, 10:30–10:45, ZEU/0260
Rational Design of Donor-Acceptor Oligomers for Enhanced Charge Separation — •Jannik Theile1, Michele Guerrini2, Surender Kumar2, and Caterina Cocchi2 — 1Physics Department and Center for Nanoscale Dynamics, Carl von Ossietzky Universität Oldenburg, Germany — 2Physics Department for Solid-State Physics and Optics, Friedrich-Schiller Universität Jena, Germany
Intramolecular charge transfer (ICT) in donor-acceptor (D-A) oligomers is central to organic optoelectronics, yet symmetric D-A-D and A-D-A systems often suffer from delocalized frontier molecular orbitals (FMOs) that hinder efficient photoinduced charge separation. To address this, we present a first-principles study based on (time-dependent) density functional theory of 22 dithieno[3,2-b:2’,3’-d]pyrrole oligomers, exploring the interplay between structural asymmetry and site-selective fluorination. Donor fluorination widens the electronic gap, while acceptor fluorination enhances charge imbalance and promotes confinement and spatial segregation of FMOs onto distinct molecular segments. The resulting optical properties reveal asymmetric, acceptor-fluorinated systems as optimal for ICT due to strong charge-transfer excitations with large oscillator strengths in the visible region. This work establishes rational design rules for conjugated D-A oligomers, showing that combining asymmetry with targeted halogenation is key to achieving robust, directional ICT and enabling high-performance organic semiconductors.
Keywords: TDDFT; D-A oligomers; halogenation; energetic properties; partial charge analysis