Dresden 2020 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 90: Perovskite and photovoltaics V (joint session HL/CPP)

CPP 90.6: Talk

Thursday, March 19, 2020, 11:15–11:30, POT 251

Charge Carrier Transport in Halide Perovskites Investigated by Optical-Pump Terahertz-Probe Spectroscopy — Hannes Hempel¹, •Andrei Petsiuk¹, Martin Stolterfoht², Pascal Becker¹, Dieter Neher², Rainer Eichberger¹, and Thomas Unold¹ — ¹Helmholtz Zentrum Berlin für Materialien und Energie GmbH — ²Institute of Physics and Astronomy, Universität Potsdam

Metal-halide hybrid perovskites exhibit excellent optoelectronic properties except for their rather moderate charge carrier mobilities. The origin of these moderate mobilities has been attributed to several (contradicting) effects, such as the formation of large and small polarons, dynamic disorder due to the soft nature of these materials, slow rotational modes of the organic molecules, as well as to the confinement of charge carriers in grains, ferroelectric domains or nanostructures. To clarify the nature of the charge carrier transport, we probed different hybrid and inorganic halide perovskites thin films and nano-crystals by temperature dependent Optical-Pump Terahertz-Probe (OPTP) spectroscopy. We find a strongly increasing mobilities with lower temperature, thus excluding small polaron formation and hopping transport. Instead, this behavior can be modeled by conventional large polaron theory and Fröhlich-type electron-phonon scattering.