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Lookup NU author(s): Dr Pablo Docampo
This is the authors' accepted manuscript of an article that has been published in its final definitive form by American Chemical Society, 2019.
For re-use rights please refer to the publisher's terms and conditions.
© Copyright 2019 American Chemical Society. To increase the moisture stability of hybrid perovskite photovoltaics, a combination of three-dimensional (3D) and a thin layer of two-dimensional (2D) perovskite incorporating long-chained organic cations is often employed as photoabsorber. However, the detailed interaction between water and 3D/2D perovskite heterojunctions has not been elucidated yet. Using in situ neutron and X-ray scattering techniques, we reveal surprisingly strong water uptake into 3D/2D perovskite films despite the presence of hydrophobic bulky cations. Our results show rapid disproportionation of the initial 2D phase (number of layers, m = 5) in methylammonium lead iodide (MAPI)/2D films into lower m phases under humidity. Nevertheless, the 2D perovskite inhibits the irreversible PbI 2 formation, which suggests that the suppression of I - and MA + ion migration and consequently of MAI escape is related to the improved moisture stability of MAPI/2D perovskite films. In comparison, quadruple-cation perovskites including Rb + exhibit poor stability toward phase segregation upon exposure to moisture regardless of the 2D perovskite layer.
Author(s): Schlipf J, Hu Y, Pratap S, Biessmann L, Hohn N, Porcar L, Bein T, Docampo P, Muller-Buschbaum P
Publication type: Article
Publication status: Published
Journal: ACS Applied Energy Materials
Online publication date: 06/02/2019
Acceptance date: 06/02/2019
Date deposited: 29/07/2019
ISSN (electronic): 2574-0962
Publisher: American Chemical Society
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