Regensburg 2025 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 36: Organic Electronics and Photovoltaics IV

CPP 36.2: Talk

Thursday, March 20, 2025, 15:15–15:30, H38

Deciphering vibronic interactions in NDI-T2 based donor-acceptor type oligomers with theoretical and experimental spectroscopy — •Maximilian F.X. Dorfner¹, Marko Medugorac¹, Ajeet Kumar², Jürgen Hauer¹, and Frank Ortmann¹ — ¹TUM School of Natural Sciences, Technische Universität München, 85748 Garching b. München, Germany — ²Department of Chemistry, Lund University, Naturvetarvägen 14 222 62 Lund, Sweden

In this study, we investigate the alternating Naphthalendiimide-bithiophene co-oligomer (T2-NDI2OD-T2), a fundamental building block of the high charge-mobility polymer-semiconductor PNDI(2OD)2T. This class of materials has garnered significant attention for its exceptional charge transport properties, making it a promising candidate for applications in field-effect transistors and as non-fullerene acceptors in organic photovoltaics. We use Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT) to examine the ground and singlet excited state properties to understand the electronic structure and vibrational excitations. Additionally, we analyze the coupling between electronic and vibrational degrees of freedom by means of a Linear Exciton-Vibrational Coupling Model parameterized by DFT. We compare the computed optical observables to the experiment and discuss the role of molecular vibrations in this system.

Keywords: Organic Semiconductors; Density Functional Theory; Exciton-Vibrational Interaction