Berlin 2024 – scientific programme
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O: Fachverband Oberflächenphysik
O 15: Organic Molecules on Inorganic Substrates II: Electronic, Optical and other Properties
O 15.2: Talk
Monday, March 18, 2024, 15:15–15:30, MA 043
Influence of Core-Substitution on the Electronic Structure of Thiadiazole Derivatives — •Mohsen Ajdari1, Felix Landwehr1, Ronja Pappenberger1, Marvin Hoffmann2, Hendrik Hoffmann3, Lukas Ahrens3, Uwe H. F. Bunz3, Andreas Dreuw2, and Petra Tegeder1 — 1Physikalisch-Chemisches Institut — 2Interdisziplinäres Zentrum für Wissenschaftliches Rechnen — 3Organisch-Chemisches Institut, Universität Heidelberg
Thiadiazole derivatives, such as naphtothiadiazole (NTD) and benzobisthiadiazole (BBT) are of great interest for the use as electron acceptor in (opto)electronic applications.
In this study, vibrational and electronic high-resolution electron energy loss spectroscopy (HREELS) in combination with quantum-chemical calculations are utilized to investigate the influence of core-substitution via halogens or aromatic groups on the adsorption geometry and electronic structure of NTD and its halogenated derivatives (NTD- Cl/Br) as well as phenyl (BBT-Ph) and thiophene (BBT-Th) substituted BBT on Au(111).
Our findings indicate that core-substitution influences the electronic structure of the corresponding molecules by narrowing of the optical gap from 2.6 eV for NTD to 2.4 eV for NTD-Cl/Br, as well as a reduction from 2.2 eV for BBT-Ph to 1.8 eV for BBT-Th. Additionally, the first triplet state energies of NTD at 1.7 eV is reduced to 1.6 eV for NTD-Cl/Br and BBT-Ph at 1.2 eV to 0.7 eV for BBT-Th.