Enhanced moisture stability of cesium lead iodide perovskite solar cells – a first-principles molecular dynamics study†
An understanding of the interaction of water with perovskite is crucial in improving the structural stability of the perovskite. Hence, in this study, the structural and electronic properties of the γ-CsPbI3(220) perovskite surface upon the adsorption of water molecules have been investigated based on density functional theory calculations. Also, we perform first-principles ab initio molecular dynamics simulations (AIMD) to explore the structural stability of the γ-CsPbI3(220) perovskite surface in the presence of water molecules, and the results are compared with the conventional cubic CH3NH3PbI3(100) perovskite surface. The water molecules show stronger interactions with the (220) surface of γ-CsPbI3 than the (100) surface of CH3NH3PbI3. However, AIMD results demonstrate that the former is much more stable, and no trace of surface degradation was observed upon the adsorption of water molecules.