Chemphyschem. 2016 May 18;17(10):1505-11. doi: 10.1002/cphc.201501168. Epub 2016 Mar 03.

Stabilization of Organic-Inorganic Perovskite Layers by Partial Substitution of Iodide by Bromide in Methylammonium Lead Iodide.

Chemphyschem : a European journal of chemical physics and physical chemistry

Raffael Ruess, Felix Benfer, Felix Böcher, Martina Stumpp, Derck Schlettwein

PMID: 26853438 DOI: 10.1002/cphc.201501168

Abstract

Thin films of the methylammonium lead halides CH3 NH3 Pb(I1-x Brx )3 are prepared on fluorine-doped tin oxide substrates and exposed to humid air in the dark and under illumination. To characterize the stability of the materials, UV/Vis spectra are acquired at fixed intervals, accompanied by XRD, energy-dispersive X-ray spectroscopy, SEM, and confocal laser scanning microscopy. Different degradation mechanisms are observed depending on the environmental conditions. It is found that bromide can successfully suppress the transformation of the perovskite into the monohydrate, presumably owing to stronger hydrogen-bonding interactions with the organic cation. However, under illumination in humid air, rather rapid decomposition of the perovskites was still observed, which is due to phase segregation. The use of increased bromide content in methylammonium lead halide absorbers is discussed in terms of their application in perovskite solar cells.

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Keywords: halides; hydrates; lead; perovskites; thin films

Publication Types

• Journal Article
• Research Support, Non-U.S. Gov't