Regensburg 2022 – scientific programme
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 4: Perovskite and Photovoltaics 1 (joint session HL/CPP/KFM)
KFM 4.5: Talk
Monday, September 5, 2022, 10:30–10:45, H34
Chemical Engineering of Ferroelastic Twin Domains in MAPbI3 Thin Films — •Yenal Yalcinkaya1, Ilka Hermes1, Tobias Seewald2, Katrin Amann-Winkel1, Lothar Veith1, Lukas Schmidt-Mende2, and Stefan A.L. Weber1 — 1Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany — 2Department of Physics, University of Konstanz, Universitätsstr. 10, 78464, Germany
In this study, we introduce a new chemical method for controlling the strain in methylammonium lead iodide (MAPbI3) perovskite crystals by varying the ratio of Pb(Ac)2 and PbCl2 in the precursor solution. We used a combination of piezoresponse force microscopy (PFM) and X-ray diffraction (XRD) to observe the effect on crystal strain. We observed larger ferroelastic twin domains upon increasing the PbCl2 content, indicating increased crystal strain via PFM images. We confirmed the increased crystal strain via the XRD patterns with strong crystal twinning features. We suggest that this behaviour is caused by different evaporation rates of methylammonium acetate and methylammonium chloride which led to a strain gradient during the crystallization as revealed by time-of-flight secondary ion mass spectroscopy (ToF-SIMS) and grazing incidence x-ray diffraction (GIXRD) measurements. We observed films with larger twin domain structures show an increased carrier via time-resolved photoluminescence (TRPL). The results demonstrate the potential of chemical strain engineering as an easy method for controlling strain-related e*ects in lead halide perovskites.