The past decade has seen an explosion of interest in the field of hybrid organic-inorganic perovskite materials. Their attractive semiconductor traits find highly promising practical use for applications such as photovoltaics (PVs), light-emitting diodes (LEDs), laser devices, ferroelectricity and multiferroicity. Initially, the term “perovskite” was coined to represent the mineral CaTiO₃, but now refers to a variety of materials possessing structures similar to that observed in CaTiO₃, i.e. ABX₃, in which A is a cation, B is a metal ion and X is an anion. The ideal perovskite adopts a cubic structure where the B-site cations are six-coordinated with X-site anions to form a corner-sharing network of BX₆ octahedra, and the larger A-site cations are caged in the three-dimensional (3D) framework. Recently, organic A-site cations and/or X-site anions were introduced into the ABX₃ structure to endow perovskites with greater structural flexibility and chemical variety, and these materials were consequently named hybrid organic-inorganic perovskites (HOIPs). Although the prototypical HOIPs exhibit 3D configurations like purely inorganic perovskites, two-dimensional (2D) HOIPs are also known, where larger organic A-site cations can separate the BX₆ octahedral layers as spacers, and these materials typically exhibit higher chemical stability. The chemistry of HOIPs almost exclusively revolves around their crystalline states. These materials show abundant and complex phase transition behaviours, which typically originate from e.g. octahedral tilting, displacements, and molecular disordering. More can be found about the chemistry and applications of HOIPs here.

The chemistry of HOIPs almost exclusively revolves around their crystalline states. These materials show abundant and complex phase transition behaviours, which typically originate from e.g. octahedral tilting, displacements, and molecular disorderin^]. By contrast, non-crystalline HOIP materials are often overlooked and receive comparatively little attention. The growing interest in non-crystalline hybrid materials has led to an increased research focus on the amorphization of HOIPs in recent years. Melt-quenched glasses formed from HOIPs are of particular interest, given their exhibition of properties not usually present in their crystalline counterparts. Such research expands the scope of the relatively new hybrid glass family, i.e., glasses containing both inorganic and organic components.

Selected References