Methylammonium Polyiodides: Remarkable Phase Diversity of the Simplest and Low-Melting Alkylammonium Polyiodide System

Andrey A. Petrov, Sergey A. Fateev, Yan V. Zubavichus, Pavel V. Dorovatovskii, Victor N. Khrustalev, Irina A. Zvereva, Andrey V. Petrov, Eugene A. Goodilin, Alexey B. Tarasov

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Newly discovered methylammonium polyiodides (MAIx) are unique precursors for innovative solvent-free technologies in perovskite photovoltaics because MAIx are liquids at room temperature and demonstrate high chemical reactivity. We investigated the features of an MAI-I2 system and built up a first phase diagram in wide temperature and composition ranges using data from differential scanning calorimetry, single-crystal X-ray diffraction, and visual thermal analysis. The phase diagram has been found to differ drastically from that of any related systems owing to the unique propensity of methylammonium toward forming a diversity of polyiodides with complicated crystal structures, namely, MAI2, MAI2.67, MAI4, and MAI5.5, found in this system for the first time. The performed density functional theory calculations revealed the crucial role of entropy contributing to the formation of higher methylammonium polyiodides, in good agreement with experimental data.

Original languageEnglish
Pages (from-to)5776-5780
Number of pages5
JournalJournal of Physical Chemistry Letters
Volume10
Issue number19
DOIs
Publication statusPublished - 3 Oct 2019
Externally publishedYes

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