Forecasting the structural
stability of hybrid organic/inorganic
compounds, where polyatomic molecules replace atoms, is a challenging
task; the composition space is vast, and the reference structure for
the organic molecules is ambiguously defined. In this work, we use
a range of machine-learning algorithms, constructed from state-of-the-art
density functional theory data, to conduct a systematic analysis on
the likelihood of a given cation to be housed in the perovskite structure.
In particular, we consider both ABC3 chalcogenide (I–V–VI3) and halide (I–II–VII3) perovskites.
We find that the effective atomic radius and the number of lone pairs
residing on the A-site cation are sufficient features to describe
the perovskite phase stability. Thus, the presented machine-learning
approach provides an efficient way to map the phase stability of the
vast class of compounds, including situations where a cation mixture
replaces a single A-site cation. This work demonstrates that advanced
electronic structure theory combined with machine-learning analysis
can provide an efficient strategy superior to the conventional trial-and-error
approach in materials design.