SKM 2023 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 18: Organic Electronics and Photovoltaics I (joint session CPP/HL)

CPP 18.13: Talk

Tuesday, March 28, 2023, 12:45–13:00, GÖR 226

Delocalization Enhances Conductivity at High Doping Concentrations — •Dennis Derewjanko¹, Dorothea Scheunemann¹, Emmy Järsvall², Anna I. Hofmann², Christian Müller², and Martijn Kemerink¹ — ¹IMSEAM, Heidelberg University, Im Neuenheimer Feld 225, 69120 Heidelberg, Germany — ²Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Gothenburg, Sweden

Many p-type organic semiconductors are experimentally found to follow a universal power-law trend between conductivity and charge carrier concentration at practically relevant high doping levels. This behavior cannot consistently be explained by conventional charge transport models. Here, we develop a physically transparent model based on the combination of a tight binding model and a variable range hopping model to show that the observed power-law trend can be explained by consideration of an energy dependent localization length. The underlying cause is an energetic lifting of the charge carriers to partly delocalized states due to the rising Fermi energy level at high charge carrier concentration. At low charge carrier concentrations, the well-known Mott-Martens model is recovered.