Atomic-Level Design of Water-Resistant Hybrid Perovskites for Solar Cells by Using Cluster Ions

Organic-inorganic hybrid perovskites have emerged as the most promising material in the development of next-generation solar cells. However, the stability of these materials exemplified by CH₃NH₃PbI₃ is the most pressing challenge; it readily decomposes when exposed to moisture. Here, we show how one can use a particular type of cluster ions, known as pseudohalides, to enhance the water resistance of the hybrid perovskite, while maintaining its favorable electronic properties. Starting with a simple physical model, we propose a new class of water-resistant hybrid perovskites as solar-cell absorbers based on the cluster ions by using DFT calculations and ab initio molecular dynamics. Limitations of applying the currently known pseudohalides for our purpose are also discussed.