Regensburg 2016 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 90: Poster III

HL 90.12: Poster

Thursday, March 10, 2016, 16:00–19:00, Poster A

Stabilization of CH₃NH₃PbI₃ in Humid Air by Partial Substitution of Iodide by Bromide — •Raffael Ruess, Martina Stumpp, and Derck Schlettwein — Institute of Applied Physics, Justus Liebig University Giessen, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany.

Thin films of methylammonium lead halides CH₃NH₃Pb(I_1−xBr_x)₃ were prepared onto FTO substrates and exposed to humid air in the dark. To characterize the stability of the materials, UV-vis spectra were acquired at fixed intervals, accompanied by X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron and confocal laser scanning microscopy. Two different degradation mechanisms were observed. It was confirmed that bromide slowed down the formation of PbI₂. Furthermore, it was found that the formation of the perovskite monohydrate phase was successfully suppressed, presumably caused by stronger hydrogen bonding interactions between the organic cation and bromide ions. The use of an increased bromide content in methylammonium lead halide absorbers is discussed for the application in perovskite solar cells.