Berlin 2018 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 46: Poster Session IV
CPP 46.19: Poster
Mittwoch, 14. März 2018, 11:00–13:00, Poster A
Rotational dynamics of methyl ammonium ions in the hybrid organic-inorganic perovskite CH3NH3PbI2.94Cl0.06 by means of QENS investigations — •Götz Schuck1, Frederike Lehmann1,2, and Susan Schorr1,3 — 1Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany — 2Universität Potsdam, Institut für Chemie, Potsdam OT Golm, Germany — 3Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
Perovskites with ABX3 - structure show a huge possibility on element substitutions on A-, B- and X-site which leads to a broad variety of physical properties. Our main field of interest is chloride substituted methyl ammonium lead triiodide in which A is the organic unit [CH3NH3]+ = MA, B = Pb2+ and X = I3−xClx. The aim is to get an inside into the interrelationship of static and dynamic structure of MAPbI3−xClx and MAPbCl3 by studying the temperature dependent methyl ammonium dynamics by means of QENS investigations in order to understand the influence of chloride on the rotational dynamics of the methyl ammonium cation.
In recent QENS investigations on MAPbI3 [1] two quasielastic components were identified in the tetragonal (165 K < T < 327 K) and cubic (T > 327 K) phase. From the QENS results, it was interpreted that in the cubic and tetragonal phases the MA ion exhibit four-fold rotational symmetry perpendicular to the C-N axis (C4) along with threefold rotation parallel to the C-N axis (C3), while in the orthorhombic Pnma phase (T < 165 K) only C3 rotation is present.
[1] Li et al., Nature Communications 2017, 8, 16086