Regensburg 2019 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 37: Poster Session III
CPP 37.15: Poster
Mittwoch, 3. April 2019, 11:00–13:00, Poster B1
Charge Carrier Dynamics of the Double Perovskite Cs2AgBiBr6 — •Robin Kentsch1, Mirko Scholz1, Jonas Horn2, Derck Schlettwein2, Kawon Oum1, and Thomas Lenzer1 — 1Physikalische Chemie, Universität Siegen, Adolf-Reichwein-Str. 2, 57076 Siegen, Germany — 2Institut für Angewandte Physik, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 16, 35392 Gießen, Germany
Hybrid lead perovskites have reached power conversion efficiencies above 23% in photovoltaic applications. Yet, major drawbacks remain. These include the toxicity of lead as well as the insufficient long-term stability. The ongoing search for environmentally friendly alternatives has identified so-called "double perovskites" with the general formula A2MM’X6 as potential replacements. Here, we report results for the charge carrier dynamics of the lead-free silver-bismuth double perovskite Cs2AgBiBr6 by employing time-resolved optical spectroscopy and electrical measurements.[1] Upon photoexcitation, we identify fast charge carrier cooling processes and pronounced coherent oscillations in the picosecond range. This is consistent with strong electron-phonon coupling. Furthermore, excitonic contributions are found. Electron-hole recombination occurs in the time range from several hundred picoseconds to microseconds. Implications of this charge carrier dynamics for the energy conversion efficiency of this lead-free perovskite in the real device will be discussed.
[1] R. Kentsch, M. Scholz, J. Horn, D. Schlettwein, K. Oum, T. Lenzer, J. Phys. Chem. C, 122, 25940 (2018).