BPCPPDYSOE21 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 7: Perovskites - organized by Eva M. Herzig (University of Bayreuth, Bayreuth)
CPP 7.12: Vortrag
Dienstag, 23. März 2021, 15:20–15:40, CPPa
Thermal decomposition dynamics of lead halide perovskite thin films — Thomas Burwig, Karl Heinze, Roland Scheer, and •Paul Pistor — MLU Martin-Luther-Universität Halle-Wittenberg
Despite the remarkable progress of lead halide perovskites, their low stability severely limits practical applications. To understand degradation pathways and pinpoint optimal compositions in terms of stability is therefore of utmost importance. Here we investigate the thermal stability of lead halide perovskite thin films grown by co-evaporation and analyze their thermal decomposition at elevated temperatures. Our approach allows to investigate the thermal decomposition by time-resolved in situ X-ray diffraction inside the vacuum growth chamber, without exposing the perovskite thin film to moisture or ambient air at any time. By applying fixed temperature ramps of 3-4 K/min. , we compare the onset of decomposition for a variety of different ABX3 compositions and explore perovskites throughout the compositional space with A=MA,FA,Cs; B=Pb,Sn,(Ag,Bi) and X=I,Br,Cl. We find an increasing decomposition temperature for the series MAPbCl3 - MAPbI3 - MAPbBr3, where the perovskite decomposes via degassing of MAX. The cation variation shows increased stability for CsPbBr3 over FAPbBr3 and MAPbBr3, mainly due to the increased sublimation temperature of CsX, which is even higher than that of PbX2. Finally, for the case of the most common and less stable MAPbX3 perovskites, a series of time-resolved degradation experiments at constant temperatures provides detailed insights into the degradation kinetics of these materials.