(220i) Computational Design of Stable Hybrid Perovskite Systems: From Mixed Cations to Surface Passivation and Elastic Properties

Here, we discuss how density functional theory (DFT) methods can help us understand the stability and efficiency challenges for hybrid organic-inorganic perovskite (HOIP) systems. Recently, we have been studying the fundamental chemistry behind the moisture degradation mechanism of 3D hybrid perovskites.[1] We have now expanded this work to study layered quasi-2D systems. A fundamental understanding of chemical interactions in these hybrid systems, garnered by a range of DFT-based computations, allows us to put forth strategies to help improve stability and efficiency of a range of HOIP-based devices. Few examples of these strategies discussed here include: mixed short organic cations, supramolecular interactions between long cations, surface passivation with acid and amine ligands and the use of defect-healing agents. We have applied these design strategies to e.g., create better efficiency LED devices. We also discuss the role of fundamental chemistry and interactions between different organic and inorganic constituents in dictating the mechanical and elastic properties of such HOIP systems, as we have discussed in a recent article.[2] It is elucidated how a multipronged computational approach which studies a range of physical and chemical phenomena from elastic properties to water intercalation, dimensional engineering and cations mixing, can create a comprehensive framework for optimization and design of this complex class of hybrid systems.

[1] Kakekhani, A., Katti, R. N., & Rappe, A. M. (2019). Water in hybrid perovskites: Bulk MAPbI3 degradation via super-hydrous state. APL Materials, 7(4), 041112.

[2] Reyes-Martinez, M. A., P. Tan, A. Kakekhani, S. Banerjee, A. A. Zhumekenov, W. Peng, O. M. Bakr, A. M. Rappe, and Y. L. Loo. "Unraveling the Elastic Properties of (Quasi) Two-Dimensional Hybrid Perovskites: A Joint Experimental and Theoretical Study." ACS Applied Materials & Interfaces (2020).