Formamidinium Haloplumbate Intermediates: The Missing Link in a Chain of Hybrid Perovskites Crystallization

Abstract

A complete screening of compositions of crystallizing products of hybrid perovskites in the most popular dimethylformamide (DMF)/ dimethyl sulfoxide (DMSO) solvents is performed for various cations (FA + / MA + ) and anions (I − /Br − ). We found four new solvate phases of formamidinium hybrid perovskites, (FA) 2 Pb 3 I 8 •4DMF, FAPbI 3 •2DMF, (FA) 5 Pb 2 I 9 •0.5DMSO, and even the bromide solvate (FA) 2 PbBr 4 •DMSO. These compounds are observed for the first time, and their refined crystal structures showed large cells of unique types dependent on solvent and perovskite compositions. We also monitored crystallization pathways of multicompositional thin films and identified phases that are able to crystallize from mixed cation and anion solutions. Based on the obtained data, we performed a deep analysis of the structural peculiarities of all the solvate phases observed in the screened compositional space and discussed how the solution composition would predetermine the early stages of crystallization of target perovskite films.

FA2PbBr4: Synthesis, Structure, and Unusual Optical Properties of Two Polymorphs of Formamidinium-Based Layered (110) Hybrid Perovskite

“…In the same manner, we attempted to obtain crystals of MABr-excessive phases from solutions of MABr:PbBr2 with different precursor ratios (up to 3:1). However, in all the cases, only bright orange MAPbBr3 perovskite crystals grew from DMF and DMSO solutions as well known for this system 17 .…”

A Theoretical Framework for Microscopic Surface and Interface Dipoles, Work Functions, and Valence Band Alignments in 2D and 3D Halide Perovskite Heterostructures

“…terminated surfaces for CsPbI 3 slab and MAI and PbI 2 -terminated surfaces for MAPbI 3 slab. To insert DMSO at the surface, we place the oxygen (O) atom of the molecule at the position of an outer terminal I (iodine) atom 41. In doing so, we remove a neighboring Cs atom or MA molecule to keep the charge neutrality of the system.…”

Manipulating Crystallization Kinetics in High‐Performance Blade‐Coated Perovskite Solar Cells via Cosolvent‐Assisted Phase Transition

“…This characteristic peak belongs to the (002) plane of FA 2 PbBr 4 •DMSO adduct (orthorhombic, Pca2 1 ). [45] No DMF-based solvent complexes are observed despite the host solvent being DMF, mainly due to the stronger Lewis basic coordination ability of DMSO than DMF. [46] A slight decrease of the (100) perovskite peak was also observed in both 10:0 and 9:1 films (Figure S2B TSAT process confirms a partial reconstruction and transformation of the metastable perovskite nuclei through the concatenation of nanostructures, thus leading to the formation of a solvent complex.…”