Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

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 CH₃NH₃PbI_2.94Cl_0.06 by means of QENS investigations — •Götz Schuck¹, Frederike Lehmann^1,2, and Susan Schorr^1,3 — 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 = I_3−xCl_x. The aim is to get an inside into the interrelationship of static and dynamic structure of MAPbI_3−xCl_x 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