Effects of Light and Electricity on Mechanical Properties of Metal Halide Perovskite Single Crystals

Metal halide perovskites (MHPs) have emerged as promising light absorber materials for their use in perovskite solar cells (PSCs). Although significant progress has been made in enhancing the efficiency and operational stability of PSCs, their mechanical reliability needs to be improved if they are to operate efficiently for many years. However, the mechanical properties of MHPs have not been fully explored. This is especially important because MHPs possess poor mechanical properties — they are compliant, soft, and brittle. To that end, we have used nanoindentation and micro-indentation to study the plastic deformation, elastic deformation, and fracture properties of MHP single crystals of various compositions. We also investigated the effects of creep as well as light and electricity on the mechanical properties of MHP single crystals. These parameters impact the mechanical properties of other similar semiconductors, and in MHPs such effects could translate to important implications for PSCs. Through this we aim to provide a more comprehensive understanding of mechanical properties of MHPs, which are relevant for understanding and enhancing the mechanical reliability of PSCs.