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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 28: Poster III
CPP 28.45: Poster
Wednesday, March 20, 2024, 11:30–13:30, Poster C
Extension of parametrization for long-range corrected DFTB and its application on organic photovoltaics — •Wenbo Sun1, Tammo van der Heide1, Carlos R. Lien-Medrano1, Thomas Frauenheim2, and Bálint Aradi1 — 1University of Bremen, Bremen 28359, Germany — 2Constructor University, Bremen 28759, Germany
In recent years, the field of organic photovoltaics (OPV) has witnessed significant progress, marked by the synthesis of novel donor and acceptor molecules. To gain deeper insights into the mechanisms of OPV and predict the electronic properties of molecules, theoretical computational methods are frequently employed. However, the application of Density Functional Theory (DFT) calculations faces limitations when dealing with large systems, such as dimers of donor-acceptor molecules or aggregates, due to their computational requirements. As an alternative, the Density Functional Tight Binding (DFTB) method is an approximation to Kohn-Sham DFT, usually being orders of magnitudes faster. For the description of charge transfer excited states by DFTB, the incorporation of long-range corrected hybrid functionals into DFTB (LC-DFTB) becomes essential.
Based on the existing ob2-1-1 parameter set [1] containing the chemical elements C, H, N, and O, the present work extends these parameters to include S, F, and Cl. The extension of parametrization broadens the scope for investigating novel OPV molecules via LC-DFTB, such as non-fullerene acceptor Y6, as well as small-molecule donors BTR and BTR-Cl, along with their respective dimers and aggregates.
[1] J. Chem. Theory Comput., 2018, 14, 115-145.
Keywords: Density Functional Tight Binding (DFTB); Organic Photovoltaics; Long-range corrected hybrid functionals; Excited states