Hybrid Halide Perovskites: Discussions on Terminology and Materials

Hybrid halide perovskites (HP) have emerged in the last decade as a new class of semiconductors with superior performances in photovoltaic and electronic devices. The literature about these halide semiconductors is abundant and a lot of names/expressions are used to define networks, structures, or materials. In this context, there is a need to offer some discussions about the relevance of using the word perovskite and the associated expressions (RP (Ruddlesden-Popper), DJ (Dion-Jacobson), ACI (alternating cations in the interlayer space), hexagonal perovskites, hollow perovskites, d-HP (deficient 3D HP),...). Moreover, the description of perovskite networks through elimination/substitution processes from the ABX(3) structure will be compared to the known dimensional reduction concept.