Mechanical Properties of Halide Perovskites: First Principles Calculations and Nanoindentation Measurements

Halide perovskites AM^IIX₃ (A = amine or alkali metal cation; M^II = divalent cation; X = Cl, Br and I) have emerged as potentially useful light-absorbing materials for solar cell applications. [1,2] One interesting and important feature is their mechanical flexibility and softness, which is crucial for the design and fabrication of devices. We have previously explored the mechanical properties of hybrid double perovskites using density functional theory combined with nanoindentation. [3–5] In this paper we review these studies and also present very recent results [6] which combine ab initio molecular dynamics and nano-indentation to investigate the mechanical properties of FAPbX₃ (FA = formamidinium). We show that the inorganic framework is the primary factor determining mechanical behavior but that hydrogen bonding can also have a significant influence.

Reference
[1] J. Am. Chem. Soc. 131, 6050 (2009).
[2] Science 338, 643 (2012).
[3] J. Mater. Chem. A 4, 12025 (2016).
[4] Chem. Mater. 29, 1089 (2017).
[5] J. Phys. Chem. Lett. 8, 5015 (2017).
[6] ChemSusChem 10, 3740 (2017).