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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 8: Hybrid and Perovskite Photovoltaics I

CPP 8.3: Vortrag

Montag, 17. März 2025, 15:45–16:00, H38

Dynamics and kinetics of light-induced phase segregation in MAPbBr_1.8I_1.2 perovskites — •Ivan Zaluzhnyy¹, Linus Pithan², Rustam Rysov², Frederik Unger^1,2, Jakub Hagara¹, Ekaterina Kneschaurek¹, Paul Zimmermann¹, Sebastian Schwartzkopff¹, Lena Merten¹, Dmitry Lapkin¹, Alexander Hinderhofer¹, Fabian Westermeier², Michael Sprung², Yana Vaynzof^3,4, Fabian Paulus^5,4, and Frank Schreiber¹ — ¹University of Tübingen — ²Deutsches Elektronen-Synchrotron DESY — ³Technical University of Dresden — ⁴Center for Advancing Electronics Dresden (cfaed) — ⁵IFW Dresden

Hybrid organic-inorganic perovskites tend to undergo several structural transformations that can be caused by temperature, humidity and light. Here we use X-ray photon correlation spectroscopy (XPCS) to study the dynamics of light-induced phase segregation in MAPbBr_1.8I_1.2 and the formation of Br-rich and I-rich domains. We observe that the phase segregation is characterized by three distinct time scales corresponding to the rapid formation of small seeds of the I-rich phase, fluctuations of the ion distribution around the quasi-equilibrium state (dynamics), and a directional drift of the ions within the crystal grains (kinetics). We also observe the influence of defects in the halide sublattice on phase separation and find that samples with interstitial halides exhibit slower phase separation as samples with vacancies in the halide sublattice.

Keywords: XPCS; X-ray; perovskites; ion migration; phase transition