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Updated: Feb 10, 2026

Monovalent Cation Doping of CH3NH3PbI3 for Efficient Perovskite Solar Cells
Published on: March 19, 2017
In situ identification of cation-exchange-induced reversible transformations of 3D and 2D perovskites
Weixin Huang1, Subha Sadhu, Pitambar Sapkota
1Radiation Laboratory, University of Notre Dame, Notre Dame, IN 46556, USA. Sylwia.Ptasinska.1@nd.edu.
Abstract:
The optical and structural properties of hybrid perovskites can be tuned by the post-synthetic introduction of new cations. To advance the development of this approach, knowledge of the reaction mechanism is essential, but has not yet been elucidated. Here, the effect of n-octylamine on three-dimensional (3D) methylammonium lead bromide (MAPbBr3) was investigated by in situ X-ray photoelectron spectroscopy. Spectroscopic analysis indicated equimolar substitutions between octylammonium (OcA+) and methylammonium (MA+) cations that cause the formation of two-dimensional (2D) octylammonium lead bromide ((OcA)2PbBr4). The introduction of methylamine reversed these changes, and the cation exchange between MA+ and OcA+ caused the reverse conversion to MAPbBr3.
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