Berlin 2018 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 11: Thin Film Properties: Structure, Morphology and Composition (XRD, TEM, XPS, SIMS, RBS, AFM, ...): Session II
DS 11.14: Vortrag
Dienstag, 13. März 2018, 13:00–13:15, H 0111
Formation and thermal stability of co-evaporated lead halide perovskite thin films (ABX3, A=MA,Cs; B=Pb; X=I,Br,Cl) analysed by in situ XRD — •Paul Pistor, Thomas Burwig, Carlo Brzuska, Rene Csuk, Wolfgang Fränzel, and Roland Scheer — Martin-Luther-Universität Halle-Wittenberg, Halle(Saale), Deutschland
Methyl ammonium (MA) lead halide perovskites (e.g. MAPbI3) are widely used to prepare efficient solar cells. In our group with have built a co-evaporation chamber equipped with a dedicated X-ray diffractometer, which allows us to study the formation and evolution of the different phases during thin film growth and under thermal stress. In this contribution, we show our investigation of the formation of single halide MAPbI3, MAPbBr3 and MAPbCl3 thin films and their thermal decomposition into lead halides at temperatures between 150∘C -250∘C. Furthermore, the miscibility of MAPbI3 and MAPbBr3 is analyzed in detail. We find a preference for phase segregation if the formation is induced with PbBr2 precursors, in contrast to the case where PbI2 is used.
Then, MAPbX3 is compared to its inorganic CsPbX3 counterparts, where e.g. a stable cubic perovskite structure is easily obtained for CsPbBr3, while for CsPbI3 two polymorphs with cubic and orthorhombic crystal structure are observed at room temperature. Finally, we find that the inorganic CsPbX3 thin films are thermally more stable and decompose at much higher temperatures (>300∘C) through the evaporation of the PbX2, leaving behind the corresponding cesium halide.