Berlin 2018 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 72: Hybrid and Perovskite Photovoltaics I

CPP 72.5: Vortrag

Donnerstag, 15. März 2018, 16:15–16:30, C 264

Correlation of ion migration and charge carrier trap states in organic-inorganic lead halide perovskites — •Susanne Koch, Susanne T. Birkhold, and Lukas Schmidt-Mende — Department of Physics, University of Konstanz, Konstanz, 78457, Germany

While the efficiencies of organic-inorganic perovskite solar cells have seen a strong rise in recent years, the understanding of physical processes inside the material is still limited and devices face stability issues. Many observed phenomena, like current-voltage hysteresis, have been attributed to mobile ions and their interaction with charge carriers. Additionally charge carrier trap states are known to have a strong impact on the carrier dynamics inside the perovskite. Since both ion migration and charge carrier trapping occur simultaneously and are influenced by common material modifications, a correlation between them is possible and could provide information on their origins and contribution to conduction processes. To characterize this possible coupling and to understand electronic and ionic conduction in the perovskite material, the energetic distribution of electronic trap states is studied by measuring thermally stimulated current, while temperature-dependent impedance spectroscopy measurements are employed to extract activation energies for the movement of ionic charges in the material. Using both techniques on comparable systems, where the perovskite is modified targeting specific trap states, should give insights into the correlation of ion migration and trap state distribution.