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Updated: Jan 15, 2026

Low Pressure Vapor-assisted Solution Process for Tunable Band Gap Pinhole-free Methylammonium Lead Halide Perovskite Films
Published on: September 8, 2017
Dimensionality Reduction of Formamidinium-Rich Lead Iodide Perovskite-Derived Structures
Takuya Ohmi1,2,3, Wataru Taniguchi1, Bhawna1,4
1Materials and Structures Laboratory, Institute of Integrated Research, Institute of Science Tokyo, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8501, Japan.
Abstract:
Formamidinium lead iodide, FAPbI3 (FA+ = CH(NH2)2+), with a cubic perovskite structure is among the most studied organic-inorganic hybrid perovskites. Despite several reports only on thin films of FA-rich lead iodide perovskites, such as FA2PbI4, their structures remain unknown due to challenges in characterizing polycrystalline films. Here, we report two new phases of FA-rich lead iodide perovskite-derived structures, FA2PbI4 and FA3PbI5, in the bulk form. These materials feature two- and one-dimensional octahedral networks of perovskite, respectively, allowing for bandgap tuning among FA-Pb-I compositions. This study presents a novel approach to controlling the structural dimensionality of perovskites and their optical properties.
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