Mechanical properties of hybrid organic-inorganic perovskites

Hybrid organic-inorganic perovskites (HOIPs) have attracted significant attention in recent years attributed to their outstanding physical properties and striking application potentials in the fields of photovoltaic and optoelectronic devices. For the commercialization of devices employing hybrid perovskite materials, their mechanical properties critically influence the manufacturing, processing as well as the device durability, and hence need to be well understood. In this review, we summarize recent mechanical studies of the known HOIPs. Firstly, we present a comprehensive account of the relationship between crystal structures and properties, where the influence of different chemical and bonding factors on the load response of HOIPs are extensively discussed. The functional abnormalities of HOIP materials under the stress stimuli are also reviewed, addressing the effects of negative linear compressibility, negative Poisson's ratio and barocaloric effect. Finally, we briefly summarize the significant effect of strain and stress in thin-film halide perovskite materials, which have been widely employed in solar cells and Light-emitting diodes. This review aims to raise more awareness about the fundamental understanding of the mechanical properties of hybrid perovskite materials, and attract more research attention to this interdisciplinary field. (C) 2019 Elsevier B.V. All rights reserved.