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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 32: Poster Session II
CPP 32.38: Poster
Donnerstag, 20. März 2025, 09:30–12:00, P3
Simulating light induced phase separation in MAPbBr1.8I1.2 perovskites — •Sebastian Schwartzkopff, Ivan Zaluzhnyy, Ekaterina Kneschaurek, Paul Zimmermann, Dmitry Lapkin, Hans Mauser, Alexander Hinderhofer, and Frank Schreiber — University of Tübingen
By changing the ratio of halides within mixed organic halide perovskites, such as MAPbBr1.8I1.2 (MA -methylammonium), one can adjust the band gap. This is quite desirable for solar cell applications where precisely tunable bandgaps enable the creation of high efficiency solar cells. However, when illuminated with visible light, these materials undergo a phase separation into Br-rich and I-rich phases, which destroys the tuned band gap. To better understand; and hopefully control this process, we utilize phenomenological approaches, such as Cahn-Hilliard and Monte Carlo models, to simulate the light-induced phase separation. We compared the results of our simulations with the experimental diffraction data. Cahn-Hilliard simulations presented quite a few difficulties in replicating the observations. The Monte Carlo simulations on the other hand allow us to investigate the influence of various material parameters on the phase separation, such as iodine-to-bromine ratio, charge carrier density and intensity of illumination. In general, we found that Monte Carlo simulations with the right choice of model parameters are quite capable of reproducing the experimental observations.
Keywords: Perovskite; X-ray diffraction; Monte Carlo; Cahn-Hilliard; Phase transition