Layer Shift Factor in Layered Hybrid Perovskites: Univocal Quantitative Descriptor of Composition-Structure-Property Relationships

The increasing interest of the scientific community in layered hybrid halide perovskites (LHHPs) as materials for innovative photovoltaic and optoelectronic applications has led to an unprecedented expansion of this family of compounds, reaching several hundred refined structures. Despite the unique structural diversity of LHHPs, traditional approaches of describing their structures, such as dividing into Dion-Jacobson (DJ) or Ruddlesden-Popper (RP) phases for most structures, are ambiguous and unquantifiable. Here, we introduced a quantitative layer shift factor (LSF) for a univocal classification and quantitative comparison of the structures. We also developed an algorithm for the automatic calculation of the LSF for such structures. We demonstrate the application of the proposed approach for an analysis of the correlations between the LSF and the band gap to reveal the structure-property relationships. Our study gives a simple and useful approach to classify either the layered perovskite-like structures or other layered compounds composed of layers of vertex-connected octahedra as a structural unit.

Automated summary

This study introduces a quantitative layer shift factor (LSF) method for unambiguous classification and quantitative comparison of LHHPs structures, along with an algorithm for automatic LSF calculation. The analysis of correlations between LSF and band gap reveals structure-property relationships, providing a simple and useful approach to classify layered compounds composed of octahedra layers.